GENERAL STATEMENT OF THE CLASS SUBJECT MATTER
A. This is the generic class for optical elements and optical systems not elsewhere classified.
Among the optical elements included in this class are:
Lenses; Polarizers; Diffraction gratings; Prisms; Reflectors;
Filters; Projection screens; Optical Modulators; Optical Demodulators; Optical Transmitters; Optical Receivers
B. Among the optical systems included in this class are:
Optical Communication; Compound lens systems; Light reflecting signalling systems (e.g., retroreflectors); Stereoscopic systems; Binocular devices; Systems of lenticular elements; Systems involving light interference; Glare reducing systems; Light dividing and combining systems; Light control systems (e.g., light valves); Building illumination with natural light; Systems for protecting or shielding elements; Optical systems whose operation depends upon polarizing, diffracting, dispersing, reflecting, or refracting light; Kaleidoscopes
C. Further included are certain apertures, closures, and viewing devices of a specialized nature which involve no intentional reflection, refraction, or filtering of light rays.
D. This class also includes optical elements combined with another type of structure(s) to constitute an optical element combined with a nonoptical structure or a perfection or improvement in the optical element. This includes filters with supports or frames; reflectors with handles, vehicles, or controlling motors; and prisms with mountings. Also, included are lenses with supports or mountings, lenses with diverse art tools, instruments or machines, lenses with casings and lenses with viewed object supports or viewed object or field illumination. Additionally, included are stereo-viewers with view changers, illumination or supporting, mounting, enclosing or light shielding structure; lenses with spacing structure such as barrels with or without an additional support, handle or illumination; and optical elements with moisture or foreign particle control.
E. Included here also are certain accessories or attachments combined with optical elements such as blinds, shields, shades, and caps or covers for preventing the accumulation of dust, moisture, or other foreign material.

LINES WITH OTHER CLASSES AND WITHIN THIS CLASS
SUPPORTS OR MOUNTS FOR OPTICAL ELEMENTS AND SYSTEMS
Included here (359) also are supports, mounts, and frames which are particularly adapted for use with optical elements. The nominal recitation of a mirror or filter in combination with such structure is generally not sufficient for classification here, if the mirror or filter is treated as a panel or lamina of general utility. Such panels with associated components, such as frames, edging, backing, etc., mechanically and permanently assembled thereto are provided for elsewhere. Supports for such panel type structures are classified elsewhere. (See References to the Current Class, below.) However, combinations of a detailed mirror with its
support are classified in this class. In the case of other optical elements, such as prisms or lenses, the broad recitation of the element in combination with the support or mounting is sufficient for classification in this class. This Class (359) provides for lenses, prisms, and filters respectively with supports. (See Subclass References to the Current Class, below.)
Stereo-viewer supports and mountings are provided for in this class. (See Subclass References to the Current Class, below.)
NONVISIBLE RADIATION
Included in this class are not only those elements which operate in the visible portion of the spectrum, but also those which operate in the near visible portion of the spectrum (i.e., infrared and ultraviolet) in accordance with optical principles. Systems which function in both the visible and near visible portions of the spectrum are classified here unless a specific structure is claimed as a result of the utilization of invisible ray energy. Systems whose operation is restricted to the nonvisible portion of the spectrum are classified elsewhere. (See References to Other Classes, below.)
OPTICAL SYSTEM INCLUDING PHOTOCELL
Generally, where a photocell is claimed as a part of the optical system, the subject matter is excluded from this class. Such subject matter is typically provided for with the art for radiant energy or measuring and testing. However, where a modulating signal is recovered from a modulated light wave (as in an optical communication receiver or in an optical demodulator), classification is in Class 359. (See References to Other Classes, below.)
OPTICAL WAVEGUIDES
Optical waveguiding elements, per se, are classified in elsewhere. Also, combinations of an optical waveguide with an associated mechanical connecting device or a device coupling light into or out of the optical waveguide are classified elsewhere. (See References to Other Classes, below.)
OPTICAL MODULATION
An optical modulator, in general, is classified in this class (359). However, optical modulation occuring solely within the confines of an optical waveguide is excluded from this class. Such subject matter is provided for in Class 385.
OPTICAL AMPLIFICATION OR FREQUENCY CONVERSION
A detailed optical amplifier/frequency converter, per se, or such subject matter in combination with an additional waveguide structure is classified in this class (359).
However, the nominal recitation of any type of optical amplifier/frequency converter together with an additional waveguide structure is classified elsewhere where such combination meets the class requirements.
MEASURING AND TESTING
A claimed image forming optical system plus a reticle is classified in this class. Sighting instruments for determining geometrical relationships where no significant optical system is claimed are classified elsewhere. Measuring and testing systems which determine the optical characteristics of light so as to measure materials and provides for lens or reflective image former testing are classified elsewhere. Eye examining and testing instruments are classified elsewhere. (See References to Other Classes, below.)
LASERS
Lasers and similar devices, per se, are excluded from this class. See References to Other Classes for lasers and similar devices when they function as a generator of coherent electromagnetic waves in the optical range.
OPTICAL TELEMETRY
Optical telemetry includes the combination of an optical data link between multiple locations together with a specific sensor used in a particular environment. Since the overall combination specifies an environment or specific sensor, the environment or sensor will control the classification. The following are examples of proper art areas for optical telemetry:
(1) Wellbore telemetry including any type of radiant energy; (i.e., optical, radio, etc.). (See References to Other Classes, below.)
(2) An optical data link in combination with a specific sensor, unless there is a place for the specific sensor in another class. (See References to Other Classes, below.)
COMPOSITIONS AND STOCK MATERIAL
Where there is no shape or structure peculiar to optical elements as in compositions or stock material, the subject matter is excluded from this class. See References to Other Classes, below, for classes that provide for these compositions and stock material.
OPTICAL ELEMENTS CLASSIFIED ELSEWHERE
For Optical Elements Classified Elsewhere, see References to Other Classes, below.
OPTICAL ELEMENTS COMBINED WITH DIVERSE TYPE ART DEVICES
An optical element combined with a diverse type art device where the element results in an improvement or perfection of the device is generally classified with the device. See Subclass References to the Current Class, below, for a reference to details of this distinction with reference to lenses, and also for references to combinations of a reflector and diverse type art device. The combination of an optical element and an electric discharge device is provided for elsewhere. See Class Definition, section D, above. (See References to Other Classes, below.)
For Classes that are more common external classifications of systems including or combined with optical elements, see References to Other Classes, below.
METHODS OF MAKING OPTICAL ELEMENTS CLASSIFIED ELSEWHERE
For Methods of Making Optical Elements Classified Elsewhere, see References to Other Classes, below.

SEE OR SEARCH THIS CLASS, SUBCLASS:
477 for stereo-viewer supports and mountings.
871 for combinations of a detailed mirror with its support.
811 831, and 892 provide for lenses, prisms, and filters respectively with supports.
809 see (1) Note for details of the following distinction with reference to lenses: an optical element combined with a diverse type art device where the element results in an improvement or perfection of the device is generally classified with the device.
838 under "SEARCH CLASS" for numerous combinations of a reflector and diverse type art device.

REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:
33, Geometrical Instruments, 227 for sighting devices for determining geometrical relationships. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
33, Geometrical Instruments, for sighting instruments for determining geometrical relationships where no significant optical system is claimed. (Lines With Other Classes and Within This Class, "Measuring and Testing")
52, Static Structures (e.g., Buildings), provides for such panels with associated components, such as frames, edging, backing, etc., mechanically and permanently assembled thereto. (See Lines With Other Classes and Within This
Class, "Supports or Mounts for Optical Elements and Systems, " above.)
65, Glass Manufacturing, 385 for processes for forming optical fibers, waveguides, or preforms; subclass 31 for chemical glass etching; subclasses 37+ for glass lens making. (See Lines With Other Classes, "Methods of Making Optical Elements Classified Elsewhere.")
117, Single-Crystal, Oriented-Crystal, and Epitaxy Growth Processes; Non-Coating Apparatus Therefor, for processes and non-coating apparatus for growing therein-defined single-crystal of all types of materials, including inorganic or organic. (See Lines With Other Classes, "Methods of Making Optical Elements Classified Elsewhere.")
156, Adhesive Bonding and Miscellaneous Chemical Manufacture, 99 for optically transparent glass sandwich making. (See Lines With Other Classes, "Methods of Making Optical Elements Classified Elsewhere.")
205, Electrolysis: Processes, Compositions Used Therein, and Methods of Preparing the Compositions, subclass 71 for the electroforming of a mirror or reflector and subclass 116 for producing a mirror or reflector by electrolytic coating. (See Lines With Other Classes, "Methods of Making Optical Elements Classified Elsewhere.")
248, Supports, 466 provides for supports for panel type structures. (See Lines With Other Classes and Within This Class, "Supports or Mounts for Optical Elements and Systems," above.)
250, Radiant Energy, 200 for optical systems for controlling or controlled by a photocell and subclasses 336.1 to 395 for methods and apparatus for the detection of invisible, radiation or the testing of material by invisible radiation for the production, transmission, control or general utilization of invisible radiant energy, including cathode rays, ultra-violet rays and the radiations and emanations of radio-active substances and the irradiation of material not limited to particular arts. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.'')
250, Radiant Energy, for systems whose operation is restricted to the nonvisible portion of the spectrum. (See Lines With Other Classes and Within This Class, "Nonvisible Radiation.")
250, Radiant Energy, 200 generally, where a photocell is claimed as a part of the optical system. (See Lines With Other Classes and Within This Class, "Optical System Including Photocell.")
252, Compositions, for compositions generally, 299.01 providing for compositions of liquid crystals and subclasses
582+ providing for other light transmission modifying compositions. (See Lines With Other Classes and Within This Class, "Compositions and Stock Material.")
264, Plastic and Nonmetallic Article Shaping or Treating: Processes, 1.1 for optical article shaping or treating. (See Lines With Other Classes, "Methods of Making Optical Elements Classified Elsewhere.")
313, Electric Lamp and Discharge Devices, 110 for an electron lamp or discharge device having an optical device structurally combined therewith. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
340, Communications: Electrical, subclass 815.76 for lens type indicator. (See Lines With Other Classes and Within This Class, "Optical Elements Classified Elsewhere.'')
340, Communications: Electrical, 853.1 for wellbore telemetry including any type of radiant energy; (i.e., optical, radio, etc.). (See Lines With Other Classes and Within This Class, "Optical Telemetry," above.)
340, Communications: Electrical, 870.28 for an optical data link in combination with a specific sensor. (See Lines With Other Classes and Within This Class, "Optical Telemetry," above.)
343, Communications: Radio Wave Antennas, 909 for radio wave refracting means and filters. (See Lines With Other Classes and Within This Class, "Optical Elements Classified Elsewhere.")
348, Television, 195, 335+, 744+, and 832+ for optical systems included in television systems. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
351, Optics: Eye Examining, Vision Testing and Correcting, 159 for spectacle lenses. (See Lines With Other Classes and Within This Class, "Optical Elements Classified Elsewhere.")
351, Optics: Eye Examining, Vision Testing and Correcting, for spectacles and instruments for vision testing and eye examining. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
351, Optics: Eye Examining, Vision Testing and Correcting, 200 for eye examining and testing instruments. (Lines With Other Classes and Within This Class, "Measuring and Testing")
352, Optics: Motion Pictures, for optical systems used in motion picture apparatus. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse
Type Art Devices.")
353, Optics: Image Projectors, for image projectors. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
356, Optics: Measuring and Testing, subclass 396 for measurements involving moire patterns caused by plural optical grids relatively movable with respect to each other and subclass 242.1 for moire pattern examination of mesh or grid like material including knitted fabrics to determine the number of threads, lines or the spacing between the lines. (See Lines With Other Classes and Within This Class, "Optical Elements Classified Elsewhere.")
356, Optics: Measuring and Testing, for methods and apparatus for analyzing light, determining the optical or nonoptical properties of materials, measuring optically dimensions, determining optically spatial relations and inspecting optically for flaws and imperfections, within the scope of this class and not otherwise classifiable. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Device.")
356, Optics: Measuring and Testing, provides generally for measuring and testing systems which determine the optical characteristics of light so as to measure materials and provides in 124 for lens or reflective image former testing. (Lines With Other Classes and Within This Class, "Measuring and Testing")
358, Facsimile and Static Presentation Processing, 400 for optical systems included in facsimile systems. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
362, Illumination, 341 and 326+ respectively for reflecting and refracting elements to be used with an artificial source of illumination.
362, Illumination, appropriate subclasses for light sources combined with optical light modifiers, especially subclass 19 for light sources with polarizers; subclasses 166+ and 293 for light sources with selected wavelength filters; subclass 268 for light sources combined with plural serial lens elements; subclasses 296+ for light sources with reflectors; subclasses 326+ and 341+ for refractors and reflectors, respectively for use with light sources. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
365, Static Information Storage and Retrieval, subclass 64, 106+, 120+, 215+, and 234+ for systems and circuits utilizing radiant energy. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
372, Coherent Light Generators, appropriate subclasses for oscillators of the quantum electronic type for generating coherent electromagnetic waves in the optical range by stimulated emission of radiation (e.g., lasers, irasers). (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
372, Coherent Light Generators, appropriate subclasses for lasers and similar devices, per se, when they function as a generator of coherent electromagnetic waves in the optical range. (See Lines With Other Classes and Within This Class, "Lasers," above.)
378, X-Ray or Gamma Ray Systems or Devices, 145 for X-ray beam control devices. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
385, Optical Waveguides, appropriate subclasses for light wave transmitting devices. (See Lines With Other Classes and Within This Class, "Optical Elements Classified Elsewhere.")
396, Photography, appropriate subclasses for still cameras. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
399, Electrophotography, 9 for diagnostics, subclasses 38+ for controls, subclasses 130+ for image formation, subclasses 168+ for charging, subclasses 177+ for exposure, subclasses 222+ for development, subclasses 297+ for transfer, subclasses 320+ for fixing, subclasses 343+ for cleaning, and subclasses 361+ for document handling. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
424, Drug, Bio-Affecting and Body Treating Compositions, 59 for a sun or radiation screening or sun tanning composition intended for topical application to a living body. (See Lines With Other Classes and Within This Class, "Compositions and Stock Materia.")
427, Coating Processes, 162 for coating processes, per se, wherein the product is an optical element. (See Lines With Other Classes, "Methods of Making Optical Elements Classified Elsewhere.")
428, Stock Material or Miscellaneous Articles, subclass 1.1 for miscellaneous liquid crystal articles and appropriate subclasses for a metallic or nonmetallic stock material product in the form of a single or plural layer web or sheet or a structurally defined or coated rod, strand, fiber flake or other element and a nonstructural metallic or nonmetallic composite web or sheet defined by the compositions of the layers. Note subclass 910 (a cross-reference art collection) for a product with molecular orientation. (See Lines With Other Classes and Within This Class, "Compositions and Stock Material.")
451, Abrading, 42 for a lens grinding process and subclasses 323 and 325 for a machine for grinding an optical lens. (See Lines With Other Classes, "Methods of Making Optical Elements Classified Elsewhere.")
505, Superconductor Technology: Apparatus, Material, Process, 100 for high temperature (T[subscrpt]c[end subscrpt] 30 K) superconducting material. (See Lines With Other Classes and Within This Class, "Compositions and Stock Materia.")
505, Superconductor Technology: Apparatus, Material, Process, 150 for high temperature (T[subscrpt]c[end subscrpt] 30 K) superconducting device, and particularly subclasses 181+ for photoconductive, light transmissive, light emissive, or light responsive device or component. (See Lines With Other Classes and Within This Class, "Optical Elements Classified Elsewhere.")
505, Superconductor Technology: Apparatus, Material, Process, 150 for high temperature (T[subscrpt]c[end subscrpt] 30 K) superconducting device; and particularly subclasses 181+ for photoconductive, light transmissive, light emissive, or light responsive device or component. (See Lines With Other Classes and Within This Class, "Optical Elements Combined With Diverse Type Art Devices.")
702, Data Processing: Measuring, Calibrating, or Testing, subclass 40, 49, 134+, and 172 for the use of radiant energy (e.g., X-ray, light, etc.) in a mechanical measurement system, flow metering, temperature measuring system, or system for measuring thickness or width, respectively, and subclass 159 for measuring of linear distance or length by reflected signal (e.g., ultrasonic, light, laser).
708, Electrical Computers: Arithmetic Processing and Calculating, subclass 816 for optical correlation or convolution and subclass 831 for electro-optical analog integrators. This class will accept optical computers where the resultant mathematical operation is in the form of an electrical signal. For mathematical operations performed by optical means, classification is in Class 359.

GLOSSARY:
BINOCULAR
Pertaining to the use of both eyes in the act of viewing.
BIREFRINGENT
Certain crystalline materials have their outer electrons bound more strongly in one direction than another resulting in the material having two refractive indices depending on the direction of the oscillation. Such materials are termed birefringent and, if an unpolarized light ray enters such a
material obliquely, it will be refracted into two different linearly polarized rays having directions of polarization which are normal to one another.
DICHROIC
As used in one sense, the term dichroic refers to (1) the property of some materials to absorb to a greater degree one or the other of the two orthogonal component vectors which can be considered as constituting ordinary light. This results in producing light polarized to a degree depending upon the relative absorption of the two components. The term dichroic is also used to refer to (2) an optical element which will transmit light of one color and reflect other colors with little light being absorbed. These elements are usually composed of superimposed strata of dielectric materials.
DIFFRACTION
A phenomenon resulting from the wave nature of light, e.g., light passing through a slit of decreasing width, forms a narrower and narrower beam until the slit width approaches the wavelength of light, after which further decreasing of the slit width results in a beam having a larger and larger divergence.
DIFFRACTION PATTERN
The intensity profile of a light beam after having passed by a diffracting aperture or object.
DIFFUSE
Pertaining to the scattering or random deviation of transmitted or reflected light.
HOLOGRAPHY
The optical recording of an object wave formed by the resulting interference pattern of two (or more) mutually coherent, component light beams. Generally, a coherent beam is first split into two component beams, one of which irradiates an object, the second of which irradiates a recording medium. The diffraction or scattering of the first wave by the object forms an object wave which proceeds to and interferes with a second coherent beam (i.e., reference beam) at the medium. The resulting pattern is a two-dimensional (thin) or three-dimensional (thick) hologram of the object wave, depending on the thickness of the recording medium.
IMAGE FORMER
An optical device capable of producing an image from light rays proceeding from an object.
INTERFERENCE
The interaction of two light waves which, as a result of their relative phases, produce a cancellation or reinforcement of wave energy.
LIGHT, VISIBLE LIGHT
Visible light is radiation which stimulates the optical receptors of the eye and has a wavelength from 3850 to 7600 Angstrom units. The term light is used to refer to wavelengths in the above mentioned range and, often, also to refer to the ranges immediately adjacent, i.e., the ultra violet and infrared ranges which are nonvisible.
OPTICAL COMMUNICATION
The conveyance of information from one location to another via at least one optical transmitter and one optical receiver. These are used to transfer the information with an optical beam and this beam can be used in various communication schemes to enable the most effective or desired method of moving the information, including optical multiplexing when plural information signals or plural transmitters and receivers are utilized.
OPTICAL ELEMENT
A structure which performs a basic optical function, i.e., the structure, when exposed to or placed in the path of a light beam, will cause refraction, diffraction, attenuation, or blocking of the light or a modification in the character or properties of the light. In lenses, the complete lens is considered an optical element, while the individual masses of a plural element lens are considered as lens elements or lens components.
OPTICAL MODULATION
The change of some characteristic of an optical beam in direct relation to a varying signal applied thereto. The change may be temporal (e.g., amplitude, frequency, or phase) or directional.
OPTICAL SYSTEM
A combination of two or more similar or diverse optical elements which are optically related.
OPTICS, OPTICAL
The science of light and vision and the construction of optical instruments.
POLARIZATION
In a beam of polarized electromagnetic radiation, the polarization direction is the direction of the electric field
vector (with no distinction between positive and negative as the field oscillates back and forth). The electric field vector is always in the plane which is normal to the beam propagation direction. At a given stationary point in space, the electric field vector of a beam can vary with time at random (unpolarized beam), can remain constant (plane-polarized beam), or can rotate. In the latter two cases, the beam is said to be "polarized" and can be thought of as the resultant vector of two orthogonal component vectors having equal amplitudes. If the phase difference of the two component vectors is 0 degrees, the light is plane polarized; if 90 degrees, the light is circularly polarized; and if it is between 0 and 90 degrees, the light is elliptically polarized. Elliptical and plane polarized light can be converted into each other by means of birefringent optical systems which retard one of the orthogonal component vectors relative to the other.
REFLECTION
Light striking a surface and returning back into the medium from which it came, at an angle equal but opposite to the angle of incidence.
REFRACTION
The deviation of light which results when a ray of light passes obliquely from a medium of one refractive index to a medium of another refractive index.
RETROREFLECTION
Light striking a surface and returning back into the medium in the reverse direction (i.e., a 180 degree change from its original path).
SPECTRUM
The band of colors produced by separating a beam of white light into its component frequencies.
TERMINAL IMAGE
The last image formed by a compound system.
ULTRAVIOLET/INFRARED
Electromagnetic radiation immediately above and below the optical visible frequency spectrum is termed ultraviolet and infrared, respectively. This entire range of frequencies is encompassed by the term "light."

HOLOGRAPHIC SYSTEM OR ELEMENT:
This subclass is indented under the class definition. Subject matter wherein apparatus for forming a record of the phase and amplitude information of a wavefront where the information can be used to reconstruct the original wavefront; apparatus to reconstruct the original wavefront from a record containing the phase and amplitude information of this wavefront; or the record itself is recited.
(1) Note. This subclass is the generic locus for subject matter relating to holography. However, where particular use or application is claimed, classification is in the appropriate use or application class.
(2) Note. Nominally claimed subject matter external to this class in combination with holography is classified here. Significantly claimed subject matter external to this class in combination with holography is classified in the class appropriate to the external subject matter.
(3) Note. Interferometers are excluded from this subclass and are classified in Class 356, subclasses 345+.
(4) Note. Holos:graphic memories including those having a nominal recitation of a photodetector or photocell are included in this or the indented subclasses. Static holos:graphic storage and retrieval systems having electrical circuitry are classified in Class 365.
(5) Note. Dynamic holos:graphic storage and retreival systems having eletrical circuitry are classified in Class 369.
(6) Note. Mere nominal recitation of developing, fixing, bleaching, or etching a photos:graphic recording medium does not exclude the subject matter from this class. Holos:graphic systems including significant chemical processing steps are classifed in Class 430, Radiation Imagery Chemistry: Process, Composition, or Product Thereof.
(7) Note. Systems for making holos:graphic matched filters are included in this and the indented subclasses.

SEE OR SEARCH THIS CLASS, SUBCLASS:
558 for correlation systems using holos:graphic matched filters.

SEE OR SEARCH CLASS:
73, Measuring and Testing, 603 and 656 for acoustic holos:graphic testing and for holos:graphic interferometry in which an object is acted upon during the test, as for example, stressed or vibrated.
235, Registers, subclass 457 for holos:graphic coded record sensors with particular circuitry to process electrical signals.
250, Radiant Energy, appropriate subclasses, for holos:graphic systems that use radiation entirely outside of the optical or microwave ranges and which is not acoustic, and subclass 550 for photocell circuits and apparatus for interference pattern analysis (e.g., holography).
283, Printed Matter, appropriate subclasses for holograms in combination with credit or identification cards.
340, Communications: Electrical, subclass 980 for nonalarm flight indicator visible in pilot's line-of-sight through windscreen..
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation), 176 for head up display combined with radar.
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, 7 for heads-up displays with selective electrical control.
348, Television, 40 for television systems which use holography.
355, Photocopying, subclass 2 for photos:graphic copying of holograms by nonholos:graphic means.
356, Optics: Measuring and Testing, subclass 457 for holos:graphic interferometry in general.
364, Electrical Computers and Data Processing Systems, for electrical computers or data processing systems which may use holography.
365, Static Information Storage and Retrieval, subclass 125, 216, and 235 for holos:graphic storage and retrieval of information systems including significant and particular electrical circuitry.
367, Communications, Electrical: Acoustic Wave Systems and Devices, 8 for acoustic holography in general.
369, Dynamic Information Storage or Retrieval, subclass 103 for dynamic storage or retrieval using a holos:graphic storage medium.
378, X-Ray or Gamma Ray Systems or Devices, subclass 36 for X-ray holography or interferometry.
380, Cryptography, subclass 54 for this subject matter used in a device for revealing concealed information.
382, Image Analysis, 210 for spatial filtering (e.g., holography) in a pattern recognition system.
396, Photography, for photography in general.
430, Radiation Imagery Chemistry: Process, Composition, or Product Thereof, 1 for holos:graphic systems involving significant chemical processing steps, composition, or product.
600, Surgery, 101 for endoscopes.

Authentication:
This subclass is indented under subclass 1. Subject matter wherein a hologram is used to provide proof that a document is not counterfeit or to make a document copy-proof.

SEE OR SEARCH CLASS:
283, Printed Matter, for document authentification with nominally recited holograms.
380, Cryptography, subclass 54 for modifying an optical image in order to conceal or reveal a hidden message.

Having particular recording medium:
This subclass is indented under subclass 1. Subject matter in which details of the internal structure of a holos:graphic recording medium is defined either physically or chemically.
(1) Note. An example of such a physical definition: "a multilayer emulsion, each layer being sensitive to a different color". A chemical defintion: "thermoplastic tape".

SEE OR SEARCH CLASS:
430, Radiation Imagery Chemistry: Process, Composition, or Product Thereof, subclass 1 for holos:graphic processes involving significant chemical processing steps composition or product; and appropriate subclasses for radiation chemical recording media, per se.

Recyclable:
This subclass is indented under subclass 3. Subject matter in which the recording medium is of such a nature that the recorded information can be erased to permit further record-erase cycles.
(1) Note. Included here are photochromics, thermochromics, dye cells, magnetic films, etc.

Magnetic material:
This subclass is indented under subclass 4. Subject matter wherein the recording medium is a material which is alterable by application of magnetic force.

Sandwich having photoconductor:
This subclass is indented under subclass 4. Subject matter in which the recording medium is integral with a layer of material which, when illuminated, undergoes a decrease in resistance.

SEE OR SEARCH CLASS:
257, Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), subclass 10, 11, 21, 53-56, 72, 113-118, 184-189, 225-234, 257, 258, 290-294, 414, 431-466, and 910 for light responsive active semiconductor devices.

Cyrstalline material:
This subclass is indented under subclass 4. Subject matter in which the recording material is either a single crystal or in polycrystalline form.

Having nonplanar recording medium surface:
This subclass is indented under subclass 3. Subject matter in which an illuminated portion of the recording medium surface is curved, as into a cylinder, or bent or folded
during recording or readout.

For synthetically generating a hologram:
This subclass is indented under subclass 1. Subject matter including means for providing a hologram of a single object by other than a single exposure to the interference pattern of light from the object as a whole and a reference beam.
(1) Note. Holos:graphic stereograms are considered recordings of different images and are excluded from this subclass.
(2) Note. Holos:graphic memories are excluded in which an object beam is scanned so as to act as a page composer when each bit is intended to be separately detected.

SEE OR SEARCH THIS CLASS, SUBCLASS:
23 for holos:graphic stereograms.

Using modulated or plural reference beams:
This subclass is indented under subclass 1. Subject matter in which a hologram is formed by interfering an object-modulated beam with another beam which is spatially or temporally modulated or with a plurality of other beams.
(1) Note. Phase modulation systems to compensate for object motion and systems for extending the depth of fluid are included here.

Spatial, phase or amplitude modulation:
This subclass is indented under subclass 10. Subject matter in which the reference beam is modulated by changing its phase, path length, or amplitude so as to have a nonuniform wavefront.

SEE OR SEARCH THIS CLASS, SUBCLASS:
22 for spatial multiplexed holograms.

SEE OR SEARCH CLASS:
365, Static Information Storage and Retrieval, subclass 49 for associative holos:graphic memories.

Copying by holos:graphic means:
This subclass is indented under subclass 1. Subject matter in which an image reconstructed from one hologram is used as the object in making a second hologram.
(1) Note. Systems in which a holos:graphic analog to an ordinary optical element is used to shape or form a beam used to make a second hologram, but which does not by itself provide the object information for the second hologram are excluded. Such systems are classified based on the other claimed features in subclass 1 and its indented subclasses.

SEE OR SEARCH CLASS:
355, Photocopying, appropriate subclasses for photos:graphic copying, in general.
399, Electrophotography, subclass 118 for optics with particular modular or displaceable structure, subclass 137 optical intermediate storage of original image, subclasses 196+ for variable magnification during exposure, subclass 216 for slit exposure by pivoting mirror, subclass 218 for lens used in exposure, and subclass 219 for fiber optics used in exposure.

Head up display:
This subclass is indented under subclass 1. Subject matter wherein a first image is optically superimposed upon a second image within a field of view.

SEE OR SEARCH CLASS:
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, 7 for heads-up displays with selective electrical control.

Holograph on curved substrate:
This subclass is indented under subclass 13. Subject matter wherein a holograph is formed on a medium which is not flat.

Using a hologram as an optical element:
This subclass is indented under subclass 1. Subject matter wherein a holos:graphic equivalent to an ordinary optical element is formed or used and wherein the holos:graphic equivalent does not itself contain any intelligence or image information more significant than a point image.
(1) Note. The optical elements for which the hologram may be substituted include lenses, reflectors, diffusers, gratings, polarizers, beam splitters or combiners, filters, and phase plates or beam couplers.

With aberration correction:
This subclass is indented under subclass 15. Subject matter which compensates for the inability of an optical system to provide a point to point correspondence between an object and its image.

Scanner:
This subclass is indented under subclass 15. Subject matter in which a hologram is used to direct a beam of light successively over the elements of a given region.
(1) Note. Systems using a holos:graphic element to convert one scan pattern to another are included here.

Flat rotating disk:
This subclass is indented under subclass 17. Subject matter where the scanning element is a planar surface, containing holos:graphic segments, which is rotated about an axis normal to the surface.

Lens:
This subclass is indented under subclass 15. Subject matter in which the holos:graphic equivalent is an optical device which focuses light.
(1) Note. Holograms which are used to form a single image of an extended two- or three-dimensional object are included here.

SEE OR SEARCH THIS CLASS, SUBCLASS:
362 for compound lens systems.
642 for lenses.

Multiple point hologram (e.g., fly-eye lens, etc.):
This subclass is indented under subclass 19. Subject matter wherein a hologram, which simulates one produced by the interference of two beams with one of the beams consisting of a plurality of separate subbeams, is produced which is the analog of a plurality of lenses in a plane such as lenticular or fly eye lens array.

Having defined page composer:
This subclass is indented under subclass 1. Subject matter including the details of the internal structure of a changeable modulator, which serves as the principle object in a system for making a plurality of holograms, where the internal conditions of the modulator represent the intelligence to be recorded in the holograms.
(1) Note. Systems in which a page composer is merely nominally recited are excluded from this subclass and are classified on the basis of the other claimed features in subclass 1 and its indented subclasses.

For producing or reconstructing images from multiple holograms (e.g., color, etc.):
This subclass is indented under subclass 1. Subject matter comprising systems specifically adapted for making a plurality of holograms, simultaneously or sequentially, of
different intelligence or for reading out images from a plurality of holograms.
(1) Note. Holos:graphic stereograms are classified in subclass 23.

SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for synthetically generating holograms.
23 for holos:graphic stereograms.

Holos:graphic stereogram:
This subclass is indented under subclass 22. Subject matter including a series of holograms made from a series of two-dimensional pictures of a three-dimensional object, each picture representing a different parallactic view of the object, and upon readout the hologram series represents a three-dimensional view to an observer.

SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for synthetically generating a hologram.
462 for nonholos:graphic stereoscopic devices.

Superimposed holograms only:
This subclass is indented under subclass 22. Subject matter in which the plurality of holograms are fully overlapped on the same recording medium only.
(1) Note. Typical subject matter of this subclass include (a) holograms made with multicolor illumination and (b) systems using spatial frequency multiplexing or pupil separation.

Discrete hologram only:
This subclass is indented under subclass 22. Subject matter in which the plurality of holograms are arranged in a side-by-side relationship on only one integral recording medium or have an equivalent fixed side-by-side spatial relationship to each other such as in a frame having windows
containing the holo-grams.
(1) Note. Space division multiplexing systems wherein holograms are discretely recorded and interlaced are included here.

SEE OR SEARCH THIS CLASS, SUBCLASS:
23 for holos:graphic stereograms.

Sequential frames on moving film:
This subclass is indented under subclass 25. Subject matter in which the plurality of holograms will, upon readout, produce images whose spatial location will move as a function of the movement of the holograms and in which movement of the holograms is used to provide for sequential readout of the individual images at a fixed location in space.
(1) Note. Holos:graphic movies or books and holograms of time varying electrical signals are typical of the subject matter included here.

Having particular laser source:
This subclass is indented under subclass 1. Subject matter including a laser as a light source wherein the physical or chemical internal structure of the laser is explicity defined.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, appropriate subclasses for lasers, per se.

Having multiple object beam or diffuse object illumination:
This subclass is indented under subclass 1. Subject matter in which a plurality of light beams are used to illuminate an object whose image is to be recorded or in which the light illuminating the object has been modulated by a diffuser or the equivalent.

Fourier transform holography:
This subclass is indented under subclass 1. Subject matter where the transmission factor of a hologram closely approximates a Fourier integral.
(1) Note. The Fourier Transform, F(w), of a function, f(t), is given by

Having optical element between object and recording medium:
This subclass is indented under subclass 1. Subject matter comprising systems for producing holograms in which an optical element, such as a lens, grating, mask, or mirror is located in the path of the light between the object whose image is to be recorded and the holos:graphic recording medium and systems for reconstructing an image from such holograms in which an equivalent optical element having an equivalent spatial location relative to the holo-gram must be used during readout.

Focused image holography:
This subclass is indented under subclass 30. Subject matter in which an image of the intelligence to be recorded is formed on, in, or very close to the recording medium when producing a hologram or in which an image is formed on, in, or very close to the hologram during readout.

For reconstructing image:
This subclass is indented under subclass 1. Subject matter used for reading out the intelligence recorded in a hologram.

Real image:
This subclass is indented under subclass 32. Subject matter for recon-structing a hologram made of an image formed by
light collected at a single point as opposed to a virtual image.

With optical waveguide:
This subclass is indented under subclass 1. Subject matter including one or more optically transparent elongated structures (e.g., rods, fibers, or waveguides) are used to transmit light rays from one point to another through modal transmission or within the confines of their outer surfaces through internal reflection.

SEE OR SEARCH CLASS:
385, Optical Waveguides, appropriate subclasses for optical waveguides, per se.

Hardware for producing a hologram:
This subclass is indented under subclass 1. Subject matter including physical components (e.g., fittings, tools, or metal equipment of a system, etc.) used in creating a holos:graphic image.

OPTICAL COMPUTING WITHOUT DIFFRACTION:
This subclass is indented under the class definition. Subject matter wherein basic and more involved mathematical processes of comparing, adding, substracting, multiplying, dividing, integrating, etc., are perfomed by optical elements on an optical beam prior to any conversion to another form of energy.
(1) Note. The optical beam itself performs the computing.
(2) Note. The computing of this and the indented subclass optically works on a single input optical beam to produce a desired output optical beam, but this optical computing is not intended to encompass convolution (crosscorrela-tion) or correlation functions performed by a diffration grating.
(3) Note. Electrical computing for optical purposes without any computation using an optical beam are not classified in this subclass (See Search Class for Class 364, subclass 200).

SEE OR SEARCH THIS CLASS, SUBCLASS:
560 for convolution or cross-correlation using a diffraction grating.
561 for correlation using a diffraction grating.

SEE OR SEARCH CLASS:
235, Registers, 200 for fluid logic.
364, Electrical Computers and Data Pro-cessing Systems, subclass 200 for general purpose programmable digital com-puter systems, and subclass 900 for miscellaneous digital data processing systems.

Logic gate:
This subclass is indented under subclass 107. Subject matter wherein the optical beam performs the operation known to be performed by an AND, OR, NOR, NOT, etc., gate and the optical beam output is the resultant of the relationship of all the input optical beams as designed prior to the application of the optical beams.

SEE OR SEARCH CLASS:
235, Registers, 200 for fluid gates.
326, Electronic Digital Logic Circuitry, for electrical digital logic circuits.
364, Electrical Computers and Data Processing Systems, subclass 194 for data processing with specific algorithm.

OPTICAL COMMUNICATION:
This subclass is indented under the class definition. Subject matter wherein an information signal is transmitted through a medium between an optical transmitter and optical receiver by means of variation in a characteristic of light waves.
(1) Note. "Light" includes infrared and ultraviolet radiation.
(2) Note. The characteristic which is varied may include, e.g., amplitude, frequency, phase, polarity, or color.
(3) Note. This subclass includes subject matter that communicates data or information from one location to another via some optical system.
(4) Note. Apparatus having a source of light signal containing information to be conveyed to a light source via an optical link are classified in this and indented subclasses regardless of the source being controlled by a different form of energy (e.g., electrical or electromagnetic field) or the optical output of the sensor being converted to a different form of energy.
(5) Note. Optical communication to objects only within a predetermined location (i.e., direction, etc.) from the source would be classified in this or indented subclasses since the prime objective is to communicate information and the actual location is only a factor to ensure that the message goes there. The detection of range, direction, etc., of the object, without any data communication to that object, would be classified in Class 356.
(6) Note. Optical switching, per se, is classified in Class 385, Optical Waveguides, but optical switching to perform a specified function would be classified with the function. Optical switching in an optical communication system, where data is moved from one location to another, is classified in this or indented subclasses.
(7) Note. The optical telemetry of Class 340, subclasses 853.1+ and Class 340, subclasses 870.28+ includes the combination of an optical communcation system, as in this subclass or the indents thereunder, combined with a particular claimed sensor. The optical communication systems of this and indented subclasses transfer optical data from one location to another via a data link but no specific sensor is set forth in the claims. For example, wellbore telemetry using any type of energy (i.e., radio, acoustic, magnetic, optic, etc.) is classified in the single art area, presently located in Class 340, subclasses 553+, since the wellbore environment is important for searching. Telemetry having a specified claimed sensor belongs with the type of sensing or in Class 340, subclasses 870.28+, if not elsewhere classified.
(8) Note. Optical communication by turning the light on and off without any modulation of the transmitted light is classified in Class 116, Signals and Indicators, subclass 20.
(9) Note. Optical communication in combination with electrical communication (Class 455, Telecommunication or Class 370, Multiplex Communications) is classified in this class.

SEE OR SEARCH THIS CLASS, SUBCLASS:
115 for optical multiplex communication with plural signal communication.
152 for optical transceivers.
174 for a repeater or relay which does not alter message content.

SEE OR SEARCH CLASS:
116, Signals and Indicators, appropriate subclasses (e.g., 20) for hellios:graphic signalling wherein signals are given by mechanically-controlled intermittant flashes of light, usually reflected sunlight.
250, Radiant Energy, 200 for electrical circuits whose operations are controlled by means of a photocell, electrical circuits for supplying current and/or potential to a photocell and photocells in combination with optical means for controlling the radiant energy which illuminated the photocell, subclasses 336.1+ for systems for detecting the presence of or measuring the quantity or quality of invisible radiant energy rays, and subclass 551 for an optical signal isolator, per se.
257, Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), subclass 13, 79-103, and 918 for incoherent light emitting injection luminescent devices.
315, Electric Lamp and Discharge Devices: Systems, appropriate subclasses for control systems for controlling the operation of electric lamps or discharge devices in which system the lamp or discharge device is the endload.
329, Demodulators, for demodulation of modulated electrical signals.
330, Amplifiers, subclass 59 for amplifiers having light-controlled or activated devices (i.e., not optical signal), and subclass 308 for amplifiers having radiant energy impinging on a semiconductor.
331, Oscillators, subclass 66 for electrical oscillators with a device responsive to heat or light.
332, Modulators, for modulators of electrical signals.
340, Communications: Electrical, 853 for wellbore telemetry that could use optical energy, and subclasses 870.28+ for telemetering systems employing radiant energy beam (e.g., Infrared) transmission.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation), appropriate subclasses for radio wave range and direction finding apparatus (Range and Direction Finding).
348, Television, 335 for electro-optical means utilized in a TV system.
352, Optics: Motion Pictures, 1 for motion picture apparatus with sound accompaniment.
356, Optics: Measuring and Testing, 3 includes optics and the optical range or remote distance finding apparatus, subclasses 26+ include optical velocity measuring, and subclasses 139+ include optical angle measuring or axial alignment.
361, Electricity: Electrical Systems and Devices, 173 for relay or electromagnet circuits utilizing photosensitive devices.
362, Illumination, 257 for light source and subclasses 317+ for light modifiers.
365, Static Information Storage and Retrieval, subclass 108 for liquid crystal radiant energy type.
369, Dynamic Information Storage or Retrieval, 100 for sound recording or reproduction utilizing electrooptical transducers or photos:graphic sound records.
372, Coherent Light Generators, for laser amplifiers and oscillators.
374, Thermal Measuring and Testing, 121 in particular for radiation responsive thermometers.
375, Pulse or Digital Communications, 219 for transceivers operated at radio frequencies.
378, X-Ray or Gamma Ray Systems or Devices.
379, Telephonic Communications, 56.1 for a light wave link for speech or a paging signal, subclasses 74+ for remote control over a telephone line, and subclasses 379+ for an optical link between the line and switching system used as a part of the line or loop condition detection.
380, Cryptography, subclass 54 for modifying an optical image to appear to be something other than what it is, i.e., to change the content to not be understandable, and subclasses 255 - 276 for communication system using cryptography particularly subclass 256 for fiber optic network using cryptography.
455, Telecommunications, for Radio Frequency Telecommunications.

Diagnostic testing of optical communication:
This subclass is indented under subclass 109. Subject matter wherein the system as a whole, not just a single piece of the system, is evaluated prior to the communication use.
(1) Note. The overall combination of an optical communication system having, for example, an optical link between a transceiver and a repeater is classified in this class.
(2) Note. If the transceiver, while operating in the total optical communication system as classified in this class, is being tested by a device using optical signals, the claimed subject matter is classified in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
177 for monitoring an optical regenerative repeater during operation.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, for optically testing of individual pieces of an optical communication system. subclass 73.1 for optical fiber or waveguide inspection.
714, Error Detection/Correction and Fault Detection/Recovery, 712 for the electrical testing of a transmission facility.

Interference signal transmission or elimination (e.g., jamming or antijamming):
This subclass is indented under subclass 109. Subject matter wherein a signal, used to interfere with a selected signal so as to prevent the intelligible reception of the selected signal, is either transmitted or eliminated.
(1) Note. The jamming signal of this subclass is independent of the information signal.

SEE OR SEARCH CLASS:
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation), 13 for radio wave jamming and antijamming.
380, Cryptography, subclasses 252-254 for concealment of information by masking (i.e., coding) of an interference bearing signal.
455, Telecommunications, subclass 1 for in-terference signal transmissions (e.g., jamming) that are telecommunication, not
optical signals.

Eavesdropping:
This subclass is indented under subclass 109. Subject matter wherein the information content of an optical communication message intended for one receiver is obtained surreptitiously by another without the other parties being notified.

SEE OR SEARCH CLASS:
379, Telephonic Communications, subclass 35 for listening-in or eavesdropping type telephonic service monitoring or observation.

Duplex:
This subclass is indented under subclass 109. Subject matter wherein a single optical link between an optical transmitter and receiver permits simultaneous transmission and reception of plural optical signals in the same or opposite directions.
(1) Note. Full duplex allows the simultaneous transmission in either of two directions, but only one direction at a time.
(2) Note. Half duplex allows data transmission in either of two directions, but only one direction at a time.

SEE OR SEARCH THIS CLASS, SUBCLASS:
152 for optical transceivers which transmit a signal in response to the received signal.

Wavelength division:
This subclass is indented under subclass 113. Subject matter wherein bi-directional transmission over a single fiber is permitted by causing two light beams to travel in different wavelength bands and different directions within the same medium.

SEE OR SEARCH THIS CLASS, SUBCLASS:
124 for wavelength division only in one direction within the same medium for multiplexing purposes.

Multiplex:
This subclass is indented under subclass 109. Subject matter wherein two or more information signals are controlled to be interleaved or simultaneously transmitted in either or both directions over a common (same) transmission medium in such a manner that the information signals may be directly recovered.
(1) Note. The use of a waveguide with an optical coupler switch to effect the multiplexing would be classified in this subclass.
(2) Note. Optical Time Slot interchange should not be included in this class since all scrambling of any energy type should go to Class 380, Cryptography.
(3) Note. Since optical demultiplex communication would often require the use of a photocell to convert the optical signal to an electrical signal, the demultiplexing is often done electrically, which is not classifiable in Class 359.

SEE OR SEARCH CLASS:
340, Communications: Electrical, 870.28 for telemetering via radiant energy beam.
348, Television, 343 for camera optical multiplexing.
380, Cryptography, subclass 36 for time segment interchange wherein slot portions of the signal are interchanged prior to transmission in order to scramble the signal.
385, Optical Waveguides, 16 for the combination of a waveguide and switch not included in an optical communication system.

Mode:
This subclass is indented under subclass 115. Subject matter wherein each light beam is applied to an optical cable at an angle which differs from the other light beams in order to be able to distinguish the light beams when they are applied to the cable simultaneously.

Spatial or switching:
This subclass is indented under subclass 115. Subject matter wherein multiple information beams are separated by the use of a switch to selectively direct individual information portions of a light beam to either separate individual light conductive elements or separate directions in space.
(1) Note. This subject matter may include a waveguide with a switch as a subcombination thereof (see Search Class Note for Class 385).
(2) Note. The optical telemetry of Class 340, subclasses 853+ and Class 340, subclasses 870.28+, include the combination of an optical communication system, as in this subclass or the indents thereunder, combined with a particular claimed sensor. The optical communication systems of this and indented subclasses transfer optical data from one location to another via a data link, but no specific sensor is set forth in the claims. For example, wellbore teleme-try using any type of energy (i.e., radio, acoustic, magnetic, optic, etc.) belongs in the single art area, presently located in Class 340, subclasses 553+, since the wellbore environment is important for searching. Telemetry having a specified claimed sensor belongs with the type of sensing or in Class 340, subclasses 870.28+.

SEE OR SEARCH CLASS:
385, Optical Waveguides, 16 for the combination of a waveguide and switch not included in an optical communications system.

Optical local area network (LAN):
This subclass is indented under subclass 115. Subject matter wherein multiple optical stations are interconnected via a network of fiber optics to enable transmission and reception between the stations.
(1) Note. Electrical wiring networks are excluded since they are not optical waveguides.

SEE OR SEARCH CLASS:
370, Multiplex Communications, appropriate subclasses for a nonoptical bus transmission local area network having token passing, loop or ring, etc.
385, Optical Waveguides, appropriate subclasses for the
fibers themselves without the optical multiplex communication environment.

Loop:
This subclass is indented under subclass 118. Subject matter wherein the local area network consists of a series of stations connected to each other and the last station is connected to the first station.

SEE OR SEARCH CLASS:
370, Multiplex Communications, appropriate subclasses, particularly 222 for fault recovery of a ring or loop network, subclass 258 for network configuration determination in a ring system, subclasses 403+ and 406 for packet switching in a ring network, and 452+ for channel assignment by polling on a ring network.

Active star:
This subclass is indented under subclass 118. Subject matter wherein an optical data distribution system, containing a common node connected to one end of each of three or more branches and the other end of the branches are connected to each member of a local area network multiplex system, permits optical information flow between all of the members; and each member receives its power (i.e., active) from the received optical signals.
(1) Note. A collision detection device in a star has its own power supply yet the incoming optical signals are not converted to electrical energy and this subject matter would be classified in this subclass.
(2) Note. Incoming optical signals which become the source of power within the star for all terminals as a result of conversion into electrical signals would be classified in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
121 for passive star local area networks (LAN's).

Passive star:
This subclass is indented under subclass 118. Subject matter wherein an optical data distribution system, containing a common node connected to one end of each of three or more branches and the other end of the branches are connected to each member of a local area network multiplex system, permits optical information flow between all of the members; and each member has its own power supply (i.e., passive) and does not change the power of the optical signals it receives from each member.

SEE OR SEARCH THIS CLASS, SUBCLASS:
120 for active star local area networks (LAN's).
178 for a star in an optical repeater.

Polarization:
This subclass is indented under subclass 115. Subject matter wherein the multiple signals are distinguished from one another by the particular individual signal vibration perpendicular to the ray direction of travel.
(1) Note. The vibrations are straight lines, circles, or ellipses which produce, respectively, plane, circular or elliptical polarization.
(2) Note. The light waves are modulated by altering the polarization (relative to a reference) in accordance with the information signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
246 for electro-optical modulation of polarized light.
281 for magneto-optical modulation of polarized light.
301 for light wave directional modulation acting on polarized light.
483 for polarization without modulation.

Time and frequency division:
This subclass is indented under subclass 115. Subject matter wherein information is transmitted on different segments of a transmission medium, which segments are divided based upon the frequency spectrum and discrete time intervals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
124 for frequency division multiplexing only.
135 for time division multiplexing only.

SEE OR SEARCH CLASS:
370, Multiplex Communications, appropriate subclasses, particularly subclass 330 and 436 for combined time and frequency channels assignments in wireless or wired multiplex communications, and subclass 478 for combined time and frequency division multiplexing.
385, Optical Waveguides, 31 for the combination of a waveguide and an input/output coupler not included in an optical communications system.

Wavelength division/frequency division (includes scattering, e.g., Raman, Brillouin, etc.):
This subclass is indented under subclass 115. Subject matter wherein (1) two or more information optical signals simultaneously present on a common optical waveguide are differentiated by optical wavelength or (2) the frequency spectrum of the optical transmission medium is divided into segments and respective information channels are transmitted in differing segments.
(1) Note. Waveguide division multiplexing (fiber optics) are identified as WDM.
(2) Note. Differing segments need not be associated on a one-to-one basis with the information channels.
(3) Note. This subject matter may include waveguide with an input/output coupler as a subcombination thereof (see Search Class Notes for Class 385).
(4) Note. Stimulated Raman effect is the amplification, built up strongly and generally exhibiting the characteristic of stimulated emission of the small portion of light that is scattered in random directions when a monochromatic light beam of high intensity is transmitted through matter. This small portion of light is equal to the frequencies of the matter.
(5) Note. A Brillouin type nonlinear opitcal device spontaneously scatters light in a medium by its interaction with sound waves passing through the medium. If this includes frequency shifted radiation with optical multiplexing, it would go into this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
114 for optical transceiver wavelength duplex wherein two optical beams having different wavelengths are transmitted in opposite directions in the same medium.
123 for time and frequency division multi-plex.
149 for photophone wherein an audio signal is directly modulated onto a light beam.
327 for Raman type frequency translators, per se.

SEE OR SEARCH CLASS:
370, Multiplex Communications, appropriate subclasses, particularly subclass 281 and 295 for frequency division in wireless or wired nonoptical duplex systems, respectively, and subclasses 343+ and 480+ for frequency division in wireless or wired nonoptical multiplex communications systems, respectively.
385, Optical Waveguides, 31 for the combination of a waveguide and an input/output coupler not included in an optical communications system.

Subscriber system:
This subclass is indented under subclass 124. Subject matter comprising plural stations prearranged to enable preselected stations to receive identified information at the same time it is transmitted.
(1) Note. These systems transmit the data without any coding, but the data itself identifies the specific stations that are to receive the transmitted data.

SEE OR SEARCH CLASS:
379, Telephonic Communications, appropriate subclasses for nonoptical subscriber checking.
380, Cryptography, appropriate subclasses for coding of the information signal to prevent unauthorized users from receiving the information.

Optical source at only one station:
This subclass is indented under subclass 125. Subject matter wherein the optical beam communicated to all of the other stations in the system originates from a single station.
(1) Note. This single station could be considered the master station since it is the source of energy for all other stations in the system.

By optical coupling:
This subclass is indented under subclass 124. Subject matter wherein the multiplexing is accomplished by the optical device itself, which permits the transfer of light from one element to another.
(1) Note. The combination of an optical coupler or input/output coupler, and wavelength division or frequency division optical communication system is classified in this subclass.

SEE OR SEARCH CLASS:
385, Optical Waveguides, subclass 15 (optical coupler) and 31 (input/output coupler) for couplers not included in an optical communication system.

Switch:
This subclass is indented under subclass 127. Subject matter wherein the optical coupler selectively determines which output receives the input light beam.

Prism:
This subclass is indented under subclass 127. Subject matter wherein a beam is coupled in or out of a waveguide to accomplish the desired multiplexing by one or more transparent bodies bounded in part by two plane surfaces which are angularly related (i.e., not parallel), at least one of these surfaces being internally reflecting or refracting to impinging incident light.
(1) Note. This subject matter includes the combination of a prism and wavelength division or frequency division optical communiction system (see Search Class Note for Class 385).

SEE OR SEARCH THIS CLASS, SUBCLASS:
831 for prisms, per se.

SEE OR SEARCH CLASS:
385, Optical Waveguides, subclass 36 for prism coupling not included in an optical communication system.

Grating:
This subclass is indented under subclass 127. Subject matter wherein (1) a beam is coupled in or out of a waveguide to accomplish the desired multiplexing by narrow parallel slits in a plate or (2) narrow parallel reflecting surfaces made by ruling grooves on polished metal break up the light waves as they emerge.
(1) Note. This subject matter includes the combination of a grating and wavelength division or frequency division optical communication system (see Search Class Note for Class 385).

SEE OR SEARCH CLASS:
385, Optical Waveguides, subclass 37 for a grating coupling not included in an optical communication sytem.

Lens:
This subclass is indented under subclass 127. Subject matter wherein a beam is coupled in or out of a waveguide to accomplish the desired multiplexing by a trans-parent optical component consisting of one or more pieces of optical glass with the surfaces so curved (usually spherical) that they serve to converge or diverge the transmited rays.
(1) Note. This subject matter includes the combination of a lens and wavelength division or frequency division optical communication system (see Search Class Note for Class 385).

SEE OR SEARCH CLASS:
385, Optical Waveguides, subclass 33 for lens coupling not included in an optical communication system.

Single source, electrically controlled:
This subclass is indented under subclass 124. Subject matter wherein a single source of light is either wavelength division or frequency division optical multiplexed via an external electrical control signal.

Different sources:
This subclass is indented under subclass 124. Subject matter wherein each channel of the common optical waveguide is supplied with data from separate origins of light.

With pump:
This subclass is indented under subclass 133. Subject matter wherein the atoms, in at least one of the sources of a medium, are caused to be raised from certain lower to certain higher energy levels to cause population inversion between certain intermediate levels in order to ultimately produce photons when the energy level moves from higher to lower levels.

SEE OR SEARCH THIS CLASS, SUBCLASS:
160 for pumping in an optical transmitter and receiver system.
345 for a particular pumping type in an optical amplifier.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, 69 for particular pumping type which is not used for amplification of a light beam input.

Time division:
This subclass is indented under subclass 115. Subject matter wherein access to the optical transmission medium is divided into discrete time intervals and information from respective channels is transmitted in differing time intervals.
(1) Note. Differing time intervals need not be associated
on a one-to-one basis with the information channels.

SEE OR SEARCH CLASS:
370, Multiplex Communications, appropriate subclasses, particularly subclass 280 and 294 for time division in wireless or wired nonoptical duplex systems, respectively, and subclasses 345+ and 498+ for time division in wireless or wired nonoptical multiplex communications systems, respectively.

Multiple access (e.g., CSMA, CDMA):
This subclass is indented under subclass 135. Subject matter wherein stations use a protocol to obtain access of a channel before sending a packet of information.
(1) Note. Frequently, CSMA networks have a collision detection capability in which the transmission is immediatedly terminated when a collision of opposing carrier signals is detected.

SEE OR SEARCH CLASS:
370, Multiplex Communications, appropriate subclasses, particularly 319, 329+, 342, 344, and 347+ for multiple access in wireless communications, and 431+ for multiple access in wired communications.

Subscriber System:
This subclass is indented under subclass 135. Subject matter wherein the system is developed to communicate with prearranged plural time division multiplexed stations, thus enabling all preselected stations to receive identified information at the same time it is transmitted.
(1) Note. These systems transmit the data without any coding, but the data itself identifies the specific stations that are to receive the transmitted data.

SEE OR SEARCH CLASS:
379, Telephonic Communications, appropriate subclasses for nonoptical subscriber checking.
380, Cryptography, appropriate subclasses for coding of the information signal to prevent unauthorized users from receiving the information.

By specific optical element:
This subclass is indented under subclass 135. Subject matter wherein the time division optical multiplexing is produced by specifically identified optical elements.

Optical switch:
This subclass is indented under subclass 138. Subject matter wherein the input light beam is optically directed to selected outputs in order to accomplish time division optical multiplexing.

With delay:
This subclass is indented under subclass 135. Subject matter wherein the time division optical multiplexing is accomplished by the use of some delay of the input light beam.

Underwater:
This subclass is indented under subclass 109. Subject matter wherein optical communication is performed via a light beam actually travelling through the water.
(1) Note. This communication can be used by underwater divers.
(2) Note. This subject matter can also be used in underwater repeaters.

SEE OR SEARCH CLASS:
367, Communications, Electrical: Acoustic Wave Systems and Devices, 131 for underwater acoustic communications systems.

Remote control:
This subclass is indented under subclass 109. Subject matter wherein a variable device is used to modulate an optical transmitter at a first location in order to control a remote electrically operated second device at a second location via an optical communication link between the transmitter and an optical receiver located at the second location and connected to the second device.
(1) Note. The devices herein specifically exclude devices solely for making information or intelligence perceptible to an individual.
(2) Note. Optical signal control devices for particular or broadly recited art devices are classified in this subclass unless there is provision for this combination in the art devices.
(3) Note. Optical signal control devices for particular art devices are classified with the art device if the features thereof are particularly recited.
(4) Note. Optical telemetry includes the combination of an optical data link between multiple locations together with a specific sensor used in a particular environment. Since the overall combination specifies an environment and specific sensor, the environment or sensor will control the classification. The following are examples of proper art areas for optical telemetry: (a) Wellbore telemetry including any type of radiant energy (i.e., optical, radio, etc.) is classified in Class 340, subclasses 853.1+; (b) An optical data link in combination with a specific sensor go to Class 340, subclasses 870.28+ unless there is a place for the specific sensor in another class, other than Class 359.

SEE OR SEARCH CLASS:
330, Amplifiers, subclass 59 for electrical amplifiers combined with a nonmodulated light controlled or activated device that is not part of the amplifying device.
379, Telephonic Communications, 74 for remote control over a telephone line.

Bidirectional (i.e., monitoring or acknowledge):
This subclass is indented under subclass 142. Subject matter wherein the optical equipment remotely controls the second device, which is unrelated to the optical system, and either (1) receives a response from the second device indicating
that the optical control signal was received or (2) monitors the second device.

SEE OR SEARCH CLASS:
340, Communications: Electrical, subclass 503 for an electrical ring back acknowledgement condition responsive indicating system and subclass 825.06 for electrical monitoring or control.

In industrial environment (e.g., robot control):
This subclass is indented under subclass 142. Subject matter wherein the second device, which is remotely controlled with optical communication, is used in the production of some manufactured product.
(1) Note. Although all patents in this subclass should be placed in Class 901, subclass 47, as a cross-reference, no orginal classifications can be placed in Class 901.

SEE OR SEARCH CLASS:
901, Robots (Cross-Reference Art Collections), subclass 47 for optical sensing device.

With radio link:
This subclass is indented under subclass 142. Subject matter wherein multiple remote devices are optically controlled via a single optical beam, but the beam is only directed at one device and this device relays control to another device via radio waves.

Wth television or radio system:
Subject matter under subclasses 142 wherein the optical link remotely controls a television or radio.
(1) Note. Optical beam control of a nominally recited T.V. or video is classified in this subclass, but specifically recited T.V. or video in combination with optical beam control is classified in Class 386, subclasses 42+ and 128+.

SEE OR SEARCH CLASS:
348, Television, subclass 734 for remote control receiver circuitry by wired or radio circuits to electrically control or mechanically control such as by a flexible shaft.
455, Telecommunications, 151 for analog modulated carrier radio wave receivers with remote control of the receiver tuning.

Switching:
This subclass is indented under subclass 142. Subject matter wherein specific connections of the remote device are controlled by an optical beam.

Plural functions:
This subclass is indented under subclass 142. Subject matter wherein more than one control is activated via the optical beam received at the remote device.

Photophone:
This subclass is indented under subclass 109. Subject matter wherein an audio signal, as the information signal, is directly modulated onto a light beam.
(1) Note. This subclass includes direct modulation of the light beam by a sound responsive mechanical device (e.g., a diaphragm).
(2) Note. The optical telephones of this subclass require the use of an optical carrier for communication information.

SEE OR SEARCH CLASS:
379, Telephonic Communications, 56.1 for a light wave link for speech or a paging signal. These would include optical telephones where connection is made through a telephone operator or exchange.

Transducer, per se:
This subclass is indented under subclass 149. Subject matter wherein the details of a device are specified, which produces a conversion between an optical beam and nonoptical energy (e.g., acoustic, electrical).

With optical fiber or waveguide:
This subclass is indented under subclass 150. Subject matter wherein the transducer either contains an optical fiber or waveguide or is connected to one.
(1) Note. An optical fiber or waveguide produces total internal confinement of an optical beam.

SEE OR SEARCH CLASS:
385, Optical Waveguides, appropriate subclasses for optical fiber or waveguides, per se.

Optical transceiver:
This subclass is indented under subclass 109. Subject matter wherein an optical transmitter and receiver are at a common location for transmission and reception of separate signals, and an optical signal is transmitted using some of the same equipment used for the reception of another optical signal.
(1) Note. The optical transmitter and receiver are confined to a common housing in a transceiver and termed "a station".
(2) Note. The simultaneous separation of a transmitter and receiver is a duplex operation and is classified in subclass 113, Duplex.

SEE OR SEARCH THIS CLASS, SUBCLASS:
113 for a duplexer which uses a single transmission line to both transmit and receive.
152 for optical transceivers in an optical communication system.
154 for an optical transmitter and receiver system in an optical communication system.
164 for plural stations having the transmitter and receiver in different housings and locations.
174 for an optical repeater communication system.
180 for an optical transmitter in an optical communication system.
189 for an optical receiver in an optical communication system.

Including compensation:
This subclass is indented under subclass 152. Subject matter wherein structure is provided within the optical transceiver to eliminate any information errors that the transceiver would produce while transmitting a response.
(1) Note. This compensation is to be effective to eliminate noise, effects of temperature, or any errors produced on the information signal caused by apparatus external or internal to the communication system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
161 for compensation in an optical communication transmitter and receiver system.

Transmitter and receiver system:
This subclass is indented under subclass 109. Subject matter wherein both the transmitter and receiver are located at separate stations for point-to-point communication from the transmitter at one location to the receiver at another location, remote from the transmitter.
(1) Note. This includes active systems wherein the receiver has its own power source for an optical beam activation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
152 for optical transceivers in an optical communication system.
174 for an optical repeater communication system.
180 for an optical transmitter in an optical communication system.
189 for an optical receiver in an optical communication system.

Presence detection:
This subclass is indented under subclass 154. Subject matter wherein an optical transmitter and receiver system is used to determine if an object is present within the range of the optical beam.

SEE OR SEARCH CLASS:
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation), 27 for radio frequency presence detection.
356, Optics: Measuring and Testing, 3 for range or remote distance (e.g., height) finding, which is useful in identifying the actual location of an object.

With polarization:
This subclass is indented under subclass 154. Subject matter wherein the optical beam of the transmitter and receiver system vibrates perpendicular to the beam's travelling direction.
(1) Note. These vibrations are in straight lines (plane polarization), circles (circular polarization), or ellipses (elliptical polarization).

SEE OR SEARCH THIS CLASS, SUBCLASS:
192 for polarization in a heterodyne optical receiver.

One transmitter, plural receivers:
This subclass is indented under subclass 154. Subject matter wherein optical information received at multiple locations is delivered by a single transmitter.

With synchronization:
This subclass is indented under subclass 154. Subject matter wherein all transmitters and receivers operate in the same time frame and their respective clocks are maintained to be at the same time and operating in an identical manner.

With alignment between transmitter and receiver:
This subclass is indented under subclass 154. Subject matter wherein the transmitter and receiver are always pointed at one another.
(1) Note. The alignment of this subclass is in an optical communication system.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, 138 for axial alignment which requires measuring to determine how to align, but not in an optical communication environment; and subclasses 399+ for lateral alignment which moves the receiver or transmitter for alignment between the two, but not in an optical communication environment.

With pumping:
This subclass is indented under subclass 154. Subject matter wherein the atoms of a medium at the transmitter are caused to be raised from certain lower to certain higher energy levels to cause a population inversion between certain intermediate levels in order to ultimately produce photons when the energy level moves from higher to lower levels.
(1) Note. This is a form of optical amplification.

SEE OR SEARCH THIS CLASS, SUBCLASS:
134 for a pump in at least one of the plural sources to produce wavelength division or frequency division multiplex.
345 for a particular pumping type in an optical amplifier.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, 69 for particular pumping type which is not used for amplification of a light beam input.

With compensation:
This subclass is indented under subclass 154. Subject matter wherein structure is provided within the optical system to eliminate from the transmitted response any information errors that the system would produce.
(1) Note. This compensation is to be effective to eliminate noise, effects of temperature, or any errors produced on the information signal as the result of apparatus external or internal to the communication system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
153 for compensation in an optical transceiver.

With electrical oscillator:
This subclass is indented under subclass 154. Subject matter wherein the transmitter and receiver optical communication system uses an electrical device whose output voltage or current is a periodic function of time.

With optical circuit board:
This subclass is indented under subclass 154. Subject matter wherein a waveguide breadboard is used to plug the transmitter and receiver into any desired location along the breadboard.
(1) Note. The circuit board is essentially an empty bus with provision for plugging an optical transmitter and receiver into it.

SEE OR SEARCH THIS CLASS, SUBCLASS:
107 for computing by the use of optical beams.

Plural stations:
This subclass is indented under subclass 154. Subject matter including at least two spaced apart stations each having a transmitter which communicates with a receiver located remote
from the transmitter.
(1) Note. Since this subclass requires that a transmitter communicate with a remote receiver, an adjacent transmitter and receiver (i.e., within a single transceiver) do not constitute a spaced apart station.

SEE OR SEARCH THIS CLASS, SUBCLASS:
152 for optical transceivers where the transmitter and receiver are adjacent one another and within a single housing.

Address directing connections:
This subclass is indented under subclass 164. Subject matter wherein the optical beam is directed to the proper station as a result of the station destination information (address) attached to the communication data on the same optical beam.
(1) Note. The address is the optical code which identifies which station is to receive the transmitted data.

Unidirectional or loopback:
This subclass is indented under subclass 164. Subject matter wherein plural stations, each having both a transmitter and receiver, are serially linked by the transmitter of the preceding station transmitting to the receiver of the next station and the last station of the system transmits to the receiver of the first station of the system.
(1) Note. If one of the stations or lines develops a fault; the last transmitted signal, which is not received by the next station intended for receipt, will be returned (loop back) to the preceding station so this station knows that the transmitted signal has not been transmitted through the entire system.

Central or master station:
This subclass is indented under subclass 164. Subject matter wherein a single central or master station, having both an optical transmitter and receiver, transmits to all of the stations in the system and also receives responses from all
of the stations of the system.
(1) Note. The central or master station can broadcast via optical signals or use fiber optic cables to link the transmitted and received optical signals.
(2) Note. The central or master station can be used in an asynchronous system of stations.

Passive system:
This subclass is indented under subclass 154. Subject matter wherein the receiver derives its power to activate itself from the beam transmitted by the transmitter.
(1) Note. The received light beam is the source for the receiver.

SEE OR SEARCH THIS CLASS, SUBCLASS:
154 for an active system.

SEE OR SEARCH CLASS:
200, Electricity: Circuit Makers and Breakers, subclass 310 for an electrical switch together with details of the indicators; Dig. 47 light guide for indicators.
250, Radiant Energy, 227.11 for shutter type optical switches.

Retroreflection:
This subclass is indented under subclass 168. Subject matter wherein the transmitted response to a received optical beam is transmitted in the opposite direction of the received beam to ensure that the original transmitter receives the response.

Retroreflection:
This subclass is indented under subclass 154. Subject matter wherein the transmitted response to a received optical beam is transmitted in the opposite direction of the received beam to ensure that the original transmitter receives the
response.

Received signal supplies power distribution to diverse devices:
This subclass is indented under subclass 154. Subject matter wherein the power for operation of devices unrelated to the transmitter and receiver system is obtained from the received signal.

Satellite communications:
This subclass is indented under subclass 154. Subject matter wherein communication is accomplished with either (1) a space orbiting satellite or (2) a land satellite.
(1) Note. The satellite communicates light waves through the air without the use of any optical conducting device.
(2) Note. The land satellite is usually located within a computer room to control multiple computers within that room or multiple rooms without the need to physically connect the computers to the satellite via optical fibers or waveguides.

Including optical waveguide:
This subclass is indented under subclass 154. Subject matter which further includes one or more transparent elongated structures (e.g., rods, fibers, or pipes) which are used to transmit light waves from one point to another within the confines of their outer surface by means of internal reflections or modal transmission.
(1) Note. An optical waveguide requires total internal reflection.
(2) Note. This subject matter includes an optical waveguide in combination with an optical transmitter and receiver system (see Search Class Note for Class 385).

SEE OR SEARCH CLASS:
250, Radiant Energy, 227.11 for photocell control that could be optical communication type modulator.
324, Electricity: Measuring and Testing, subclass 95 for measuring, testing, or sensing electricity, per se, with waveguide or long line.
385, Optical Waveguides, appropriate subclasses for optical waveguide structure, per se.

Optical repeater system:
This subclass is indented under subclass 109. Subject matter including apparatus for receiving a light wave signal and reradiating the signal at a different carrier frequency and usually at a higher energy level or in a desired direction.
(1) Note. Where the transmitted signal has a different information content than the received signal, classification is not in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
152 for optical transceivers in an optical communication system.
154 for an optical transmitter and receiver system in an optical communication system.
180 for an optical transmitter in an optical communication system.
189 for an optical receiver in an optical communication system.

SEE OR SEARCH CLASS:
178, Telegraphy, 70 for repeaters specific to telegraphy.
330, Amplifiers, for amplifier systems in general, particularly subclass 10 for modulator-demodulator type amplifiers for amplifying direct current or slowly varying alternating current signals.
332, Modulators, subclass 183 for modulation converters for converting one modulated wave to a differently modulated wave (e.g., pulse modulation to frequency modulation or frequency modulation to amplitude modulation); subclass 108 for plural stage modulation systems wherein each stage is of the same or diverse type of modulation, the last stage being of the pulse modulation type; subclasses 119+ or 144+ for plural stage modulation systems wherein the last stage is of the phase or frequency modulation type; and subclasses 151+ for plural stage modulation systems wherein the last stage is of the amplitude modulation type.
333, Wave Transmission Lines and Networks, 117 for hybrid type networks.
340, Communications: Electrical, subclass 291 for signal box repeaters which repeat, for example, signals received at a central station to a plurality of fire houses.
375, Pulse or Digital Communications, 211 for repeater for a pulse or digital signal in the radio frequency range.
455, Telecommunications, 7 for repeaters for analog signals in the radio frequency range.

Demodulating:
This subclass is indented under subclass 174. Subject matter wherein the optical repeater extracts the information content of the signal it receives prior to reradiating the signal at the same or different carrier frequency.
(1) Note. Although there are various reasons for demodulating prior to transmission, the following are examples:
(a) To enable retransmission with a different modulation than received, or
(b) The demodulation is necessary to determine the reradiated destination for the received signal.

Regenerative:
This subclass is indented under subclass 174. Subject matter wherein the repeater samples the incoming optical beam without any demodulation and then transmits it with perfect timing and no distortion.
(1) Note. This involves positive feedback of the incoming signal.

Monitoring:
This subclass is indented under subclass 176. Subject matter wherein the regenerative repeater includes apparatus to check the system during operation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
110 for diagnostic testing of the optical communication system prior to communication use.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, for optical testing of individual pieces of an optical communication system, e.g., subclass 73.1 for optical fiber or waveguide inspection.
714, Error Detection/Correction and Fault Detection/Recovery, 712 for the electrical testing of the information content of a transmission facility.

Star:
This subclass is indented under subclass 174. Subject matter wherein an optical data distribution system contains a common node connected to one end of each of three or more branches and the other end of the branches are connected to appropriate elements of an optical repeater.

SEE OR SEARCH THIS CLASS, SUBCLASS:
120 for an active star LAN.
121 for a passive star local area network (LAN).

Including optical waveguide:
This subclass is indented under subclass 174. Subject matter which further includes one or more transparent elongated structures (e.g., rods, fibers, or pipes) which are used to transmit light waves from one point to another within the confines of their outer surface by means of internal reflections or modal transmission.
(1) Note. This requires total internal reflection.
(2) Note. This subject matter includes an optical waveguide in combination with an optical repeater system (see Search Class Notes for Class 385).

SEE OR SEARCH CLASS:
250, Radiant Energy, 227.11 for photocell control that could be optical communication type modulator.
324, Electricity: Measuring and Testing, subclass 95 for measuring, testing, or sensing electricity, per se, with waveguide or long line.
385, Optical Waveguides, appropriate subclasses for optical waveguide structure, per se.

Transmitter:
This subclass is indented under subclass 109. Subject matter which converts information signals into modulated light wave signals suitable for propagation through or along a transmission medium.
(1) Note. There are some documents in this subclass that use incandescent bulbs for the transmitter.
(2) Note. An optical transmitter contains an optical modulator together with the other elements required to communicate the information from one location to another via an optical beam.

SEE OR SEARCH THIS CLASS, SUBCLASS:
152 for optical transceivers in an optical communication system.
154 for an optical transmitter and receiver system in an optical communication system.
174 for an optical repeater communication system.
189 for an optical receiver in an optical communication system.
237 for optical modulators, per se.

With particular modulation:
This subclass is indented under subclass 180. Subject matter wherein apparatus is set forth to include the information signal in a specified manner onto a light wave carrier entering the device.

SEE OR SEARCH THIS CLASS, SUBCLASS:
237 for optical beam modulation without a transmitter.

SEE OR SEARCH CLASS:
250, Radiant Energy, 493.1 for radiant energy generation and sources.
348, Television, for projection TV modulated laser beam which requires scanning as distinguished from the optical communication of Class 359.
369, Dynamic Information Storage or Retrieval, subclass 104 for a ribbon light modulator for radiation beam modification of or by a storage medium.
372, Coherent Light Generators, subclass 38 for coherent light generators with particular component circuitry.

Frequency modulation:
This subclass is indented under subclass 181. Subject matter wherein the instantaneous amplitude of the information signal (i.e., modulating signal) modulates a carrier so that its instantaneous frequency differs from the carrier frequency by an amount proportional to the information signal amplitude.
(1) Note. Combinations of phase and frequency modulation are commonly referred to as frequency modulation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
183 for an optical transmitter using phase modulation.

Phase modulation:
This subclass is indented under subclass 181. Subject matter wherein the instantaneous amplitude of the information signal (i.e., modulating signal) modulates a sine-wave carrier so that its instantaneous angle (i.e., phase) deviates from the original (no-signal) angle by an amount proportional to the information signal amplitude.

SEE OR SEARCH THIS CLASS, SUBCLASS:
182 for an optical transmitter using frequency or frequency and phase modulation.

Pulse modulation:
This subclass is indented under subclass 181. Subject matter wherein the carrier signal is transmitted in a series of pulses, having a normally constant value with a variation of a rise and a decay approaching infinitesimal duration, to convey the information contained in the modulating signal.
(1) Note. This subclass includes pulse amplitude, delta, and pulse frequency modulation.
(2) Note. Pulse amplitude modulation uses the amplitude of the transmitted carrier signal to convey the information contained in the modulating signal.
(3) Note. A delta pulse code modulation converts audio signals into corresponding trains of digital pulses to provide greater freedom from interference during transmission.
(4) Note. Pulse frequency modulation varies the transmitted pulse repetition rate as a function of the instantaneous value of the information signal (i.e., modulating signal).

SEE OR SEARCH THIS CLASS, SUBCLASS:
186 for pulse time modulation.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, 100 for miscellaneous pulse parameter (e.g., amplitude) control.
329, Demodulators, 311 for electrical pulse demodulators.
332, Modulators, 106 for electrical pulse modulators.
370, Multiplex Communications, subclass 533 for multiplexers/distributors using pulse amplitude modulation.
375, Pulse or Digital Communications, subclass 353 for electrical pulse amplitude modulation. Subclasses 259+, 301+, and 321+ for pulse or digital communications via modulated carrier waves.

Pulse-code:
This subclass is indented under subclass 184. Subject matter wherein the information signal is periodically sampled and each sample is quantized and transmitted as a digital binary code.

SEE OR SEARCH THIS CLASS, SUBCLASS:
186 for pulse time modulation.

Pulse time:
This subclass is indented under subclass 184. Subject matter wherein the values of instantaneous samples of the information signal (i.e., modulating signal) are made to modulate the occurrence time of some characteristic of a pulse carrier.
(1) Note. This subclass includes pulse position and pulse width modulation.
(2) Note. Pulse position modulation modulates the position in time of a transmitted pulse with respect to each sampled instantaneous value of the information signal (i.e., modulating signal).
(3) Note. Pulse width, also identified as pulse duration, modulation controls the width of the transmitted pulse relative to each sampled instantaneous value of the information signal (i.e., modulating signal).

With feedback:
This subclass is indented under subclass 180. Subject matter wherein at least a portion of the optically transmitted light wave is sampled and used to further control the transmitted light beam.
(1) Note. The actual signal feedback that controls the transmitter can be either optical or an electrical equivalent of the sampled transmitted optical light beam.

Including optical waveguide:
This subclass is indented under subclass 180. Subject matter which further includes one or more transparent elongated structures (e.g., rods, fibers, or pipes) which are used to transmit light waves from one point to another within the confines of their outer surface by means of internal reflections or modal transmission.
(1) Note. This requires total internal reflection.
(2) Note. This subject matter includes an optical waveguide in combination with an optical transmitter (see Search Notes for Class 385).

SEE OR SEARCH CLASS:
250, Radiant Energy, 227.11 for photocell control that could be optical communication type modulator.
324, Electricity: Measuring and Testing, subclass 95 for measuring, testing, or sensing electricity with waveguide or long line.
385, Optical Waveguides, appropriate subclasses for optical waveguide structure, per se.

Receiver:
This subclass is indented under subclass 109. Subject matter wherein the information or modulating signal which has been transmitted may be derived from the received modulated light wave signals and converted into signals corresponding to the information transmitted.
(1) Note. This classification is restricted to those devices peculiar to light wave communication with information modulated thereon not merely a nonmodulated light control signal to control or activate an electrical amplifier in Class 330, subclass 59.
(2) Note. An optical receiver contains an optical demodulator together with other elements required to communicate information from one location to another via an optical beam.

SEE OR SEARCH THIS CLASS, SUBCLASS:
152 for optical transceivers in an optical communication system.
154 for an optical transmitter and receiver system in an optical communication system.
174 for an optical repeater communication system.
180 for an optical transmitter in an optical communcation system.

SEE OR SEARCH CLASS:
250, Radiant Energy, 206 for photocell controlled circuits
of general utility, and subclasses 336.1+ for invisible radiant energy responsive electric signalling.
330, Amplifiers, subclass 59 for electrical amplifiers combined with a nonmodulated light controlled or activated device that is not part of the amplifying device.
356, Optics: Measuring and Testing, appropriate subclasses for the measuring or testing of an optical property.

Homodyne:
This subclass is indented under subclass 189. Subject matter wherein a locally generated voltage at the received carrier frequency will result in a zero beat reception for detection of the transmitted information signal.
(1) Note. This is also called a zero-beat demodulator.
(2) Note. Any further processing of the output of the demodulator will use electrical signals since the intermediate frequency (IF) output is outside the frequency spectrum of optical signals.
(3) Note. An electrical or optical local oscillator used in combination with a homodyne optical receiver is classified in this subclass.

Heterodyne:
This subclass is indented under subclass 189. Subject matter wherein the received wave is combined with a locally generated wave in a nonlinear device to produce sum and difference frequencies at the output.
(1) Note. This is also called a beat demodulator.
(2) Note. Any further breakdown of the output of the demodulator will use electrical signals since the intermediate frequency (IF) output is outside the frequency spectrum of optical signals.
(3) Note. An electrical or optical oscillator used in combination with a heterodyne optical receiver is classified in this subclass.

With polarization:
This subclass is indented under subclass 191. Subject matter wherein the heterodyne optical demodulating receiver is used to detect a light wave having vibrations perpendicular to the direction of travel of the light beam.
(1) Note. These vibrations are in straight lines (plane polarization), circles (circular polarization), or ellipses (elliptical polarization).

SEE OR SEARCH THIS CLASS, SUBCLASS:
156 for polarization in an optical transmitter and receiver communication system.
190 for homodyne demodulation.
246 for electro-optic modulation of polarized light.
281 for magneto-optic modulation of polarized light.
301 for light wave directional modulation acting on polarized light.
483 for polarization without modulation.

With optical element (e.g., lens, mirror, etc.):
This subclass is indented under subclass 189. Subject matter wherein an optical receiver comprises some type of optical device such as a lens, etc., other than an optical waveguide.
(1) Note. The optical elements for this subclass are those defined as being classified in Class 359, not the optical waveguides of Class 385.

SEE OR SEARCH THIS CLASS, SUBCLASS:
195 for an optical receiver with an optical waveguide.

SEE OR SEARCH CLASS:
385, Optical Waveguides, appropriate subclasses for optical waveguide structure, per se.

Automatic gain control:
This subclass is indented under subclass 189. Subject matter wherein the amplitude of an output signal amplitude is maintained constant either by an optical or electrical device.
(1) Note. This control must be in the environment of an optical receiver.

With optical waveguide:
This subclass is indented under subclass 189. Subject matter which further includes one or more transparent elongated structures (e.g., rods, fibers, or pipes) which are used to transmit light waves from one point to another within the confines of their outer surface by means of internal reflections or modal transmission.
(1) Note. An optical waveguide requires total internal reflection.
(2) Note. The combination of an optical receiver with an optical waveguide as defined in Class 385 is classified in this subclass (see Search Class Note for Class 385).

SEE OR SEARCH THIS CLASS, SUBCLASS:
193 for an optical receiver in combination with an optics element as classified in Class 359.

SEE OR SEARCH CLASS:
250, Radiant Energy, subclass 206 for photocell control that could be an optical communication type modulator.
324, Electricity: Measuring and Testing, subclass 95 for measuring, testing, or sensing electricity, per se, with waveguide or long line.
385, Optical Waveguides, appropriate subclasses for optical waveguide structure, per se.

DEFLECTION USING A MOVING ELEMENT OR MEDIUM (OFFSETTING OR CHANGING AT LEAST A PORTION OF THE BEAM):
This subclass is indented under the class definition. Subject matter comprising structure for offsetting or changing the direction of at least a portion of the incident light by moving a light reflecting or transmitting element or
medium into or out of the light beam or by changing the position of a reflecting or transmitting element or medium in the light beam.
(1) Note. A prism may be employed for refracting or reflecting light. Prism reflections are considered to be internal reflections; that is, the light is inside the prism body before and immediately after reflection. Light beam deflection by a movable prism is included in this subclass.
(2) Note. Lenses or curved surface mirrors movable for focusing are classified elsewhere in this class.

SEE OR SEARCH THIS CLASS, SUBCLASS:
197 for light beam deflection by a periodically moving element.
298 for light wave directional modulation.
577 for light control by light interference.
831 for prisms in general.

SEE OR SEARCH CLASS:
250, Radiant Energy, 503.1 for an invisible radiation source with a radiation modifying member, in general, and subclasses 505.1+ for radiation-controlling elements, per se, exclusive of infrared, visible, and ultraviolet types.
348, Television, for mechanical-optical scanning by moving a lens or refractor.

Using a periodically moving element (periodic change of optically reflecting, refracting or diffracting element):
This subclass is indented under subclass 196. Subject matter including an optically reflecting, refracting, or diffracting element as the scanning element whose orientation is changed in a periodic manner.
(1) Note. The motion of reflectors resulting from vehicle vibration, the motion of vehicle wheels, the action of wind, etc., is considered to be of an irregular nature and not periodic within the meaning of this definition.

SEE OR SEARCH THIS CLASS, SUBCLASS:
227 for light interrupting by means of movable elements containing alternating transparent and opaque areas.

SEE OR SEARCH CLASS:
348, Television, 195 for mechanical-optical scanning and subclasses 474+ for a facsimile scanning signal generator.
352, Optics: Motion Pictures, subclass 84 for high speed cameras which use rotating optical elements and subclasses 105+ for motion picture optical rectifiers using rotating or scanning optical elements.
358, Facsimile and Static Presentation Processing, 474 for a facsimile scanning signal generator.

Particular mount or driver for element:
This subclass is indented under subclass 197. Subject matter wherein details of the structure for supporting the moving element or for moving it are claimed.

Particular oscillating driver:
This subclass is indented under subclass 198. Subject matter wherein a specific device imparting back and forth motion to the element is recited.

Bearing or shaft for rotary driver:
This subclass is indented under subclass 198. Subject matter wherein a specific rod transmitting rotational motion from a driver or the supporting device within which the rod turns is recited.

Plural moving scanning elements:
This subclass is indented under subclass 197. Subject matter wherein deflection is achieved by multiple optical elements which are not stationary.

X-Y scanner:
This subclass is indented under subclass 201. Subject matter wherein the multiple elements cause a deflection of light in two mutually perpendicular directions.

Having a common axis of rotation:
This subclass is indented under subclass 201. Subject matter wherein the multiple elements revolve around the same line.

Utilizing plural light beams:
This subclass is indented under subclass 197. Subject matter wherein the periodically moving element deflects or scans more than a single light beam simultaneously.

Having particular focusing element to receive scanned light:
This subclass is indented under subclass 197. Subject matter wherein a specific optical element gathers light from the actual scanning element.

High distortion lens (e.g., fQ lens, etc.):
This subclass is indented under subclass 205. Subject matter including a lens which forms an image which is not in proportion to a respective image source.
(1) Note. An fQ lens is one in which the image height is equal to the product of the lens focal length and the angle at which a beam enters the lens.

SEE OR SEARCH THIS CLASS, SUBCLASS:
662 for an fQ lens, per se.

Anamorphic element:
This subclass is indented under subclass 205. Subject matter including an element (usually a lens) for producing magnification in a first plane which differs from that in a plane perpendicular thereto.

SEE OR SEARCH THIS CLASS, SUBCLASS:
668 for an anamorphic lens, per se.

Concave reflector:
This subclass is indented under subclass 205. Subject matter wherein a mirror-like element indented away from incident light receives the scanned light.

SEE OR SEARCH THIS CLASS, SUBCLASS:
838 for reflectors, in general.

Including transmissive type moving element:
This subclass is indented under subclass 197. Subject matter wherein the medium of the scanning element permits the passage of light rays.

Having moving lens:
This subclass is indented under subclass 209. Subject matter including opposed shaped and spaced refracting surfaces either of a (1) single transparent mass or (2) plurality of such masses arranged in series along an optical axis to produce a single output image from an object, which are both external to the mass or masses, from the object light rays passing therethrough.

SEE OR SEARCH THIS CLASS, SUBCLASS:
642 for lenses generally.

Having moving prism:
This subclass is indented under subclass 209. Subject matter including one or more transparent bodies bounded in part by two plane surfaces which are angularly related (i.e., not parallel), at least one of these surfaces being internally reflecting or refracting to impinging incident light.
(1) Note. A prism may be employed for refracting or reflecting light. Prism reflections are considered to be internal reflections; that is, the light is inside the prism body both before and immediately after the reflection.

SEE OR SEARCH THIS CLASS, SUBCLASS:
592 for refracting elements employed in natural light directing systems.
606 for prismoidal antiglare mirrors.
618 for plural path optical systems which divide or combine the light paths.
831 for a prism, per se.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, 51 for optical test devices having prisms used in the infrared or ultraviolet range alone or in combination with visible light, subclasses 300+ for prism type spectroscopic instruments, and subclasses 331+ for prism type monochromators.

Including reflective type moving element:
This subclass is indented under subclass 197. Subject matter wherein a light wave that strikes the medium of the moving element is returned to the original medium with the angles of incidence and reflection equal and lying in the same plane.

SEE OR SEARCH THIS CLASS, SUBCLASS:
838 for reflectors in general.

Having oscillating element:
This subclass is indented under subclass 212. Subject matter wherein the reflecting element has oscillating or vibrating motion.

SEE OR SEARCH THIS CLASS, SUBCLASS:
520 for signal reflectors vibrating, oscillating, and rotating.

Single plane mirror element:
This subclass is indented under subclass 213. Subject matter wherein the element is unitary, flat and reflecting.

With imaging lens:
This subclass is indented under subclass 214. Subject matter having a lens typically referred to as an imaging lens.

Having multifaceted rotating element:
This subclass is indented under subclass 212. Subject matter wherein the reflecting element has plural sides or faces.

With facets parallel to rotation axis:
This subclass is indented under subclass 216. Subject matter wherein the faces or sides of the reflective element are parallel to the axis of rotation.

Having six, seven, or eight facets:
This subclass is indented under subclass 217. Subject matter wherein the element has more than five facets and less than nine facets.

Having five or fewer facets:
This subclass is indented under subclass 217. Subject matter wherein the element has less than six facets.

Having planar rotating reflector with transverse rotation axis:
This subclass is indented under subclass 212. Subject matter wherein the faces of the rotating reflector are not curved and the faces are tilted with respect to the rotation axis.

Having planar rotating reflector with rotation axis in its plane:
This subclass is indented under subclass 212. Subject matter wherein the faces of the rotating reflector are not curved and the faces are parallel to the axis of rotation.

By frustrated total internal reflection:
This subclass is indented under subclass 196. Subject matter wherein a light transparent element has a surface adjacent a second element or medium which is movable into and out of optical contact with the surface.
(1) Note. A light beam incident on the surface undergoes total internal reflection. By bringing the second element or medium into proximity with the surface of the transparent element, total internal reflection becomes frustrated and the light beam is no longer totally internally reflected, but instead, is passed into the second element or medium.

By moving a reflective element:
This subclass is indented under subclass 196. Subject matter wherein the direction of at least a portion of an incident light beam is offset or changed by moving a light-reflecting element into or out of the light beam or by changing the orientation of the reflecting element in the light beam.

SEE OR SEARCH THIS CLASS, SUBCLASS:
196 for light beam deflection by a movable reflective prism.
212 for light beam deflection by periodically moving reflectors.
291 for light control by deforming or flexing a reflector.
838 for reflectors or reflecting systems in general.

SEE OR SEARCH CLASS:
250, Radiant Energy, subclass 230 for reflection-type light valves used in photocell systems.
324, Electricity: Measuring and Testing, subclass 97 for galvanometers of the light beam type.
348, Television, 203 for mechanical-optical scanning by a moving reflector.

Reflective element moved by deformable support:
This subclass is indented under subclass 223. Subject matter wherein a support element is extended or contracted to modify the position of the reflecting element.

Pivoting or moving in circular arc:
This subclass is indented under subclass 223. Subject matter wherein the motion of the moving element traces out a portion of a complete revolution.

Rotating:
This subclass is indented under subclass 223. Subject matter wherein the reflective element revolves completely around an axis.

LIGHT CONTROL BY OPAQUE ELEMENT OR MEDIUM MOVABLE IN OR THROUGH LIGHT PATH:
This subclass is indented under the class definition. Subject matter comprising the control of the amount of light transmitted through an area defined by an optical beam via an element or material, which is either completely opaque or opaque only in certain portions whereas the other portions are transparent, by (1) selectively intercepting the light path by the element or (2) changing the orientation of the element within the light path.
(1) Note. Where the element is not substantially opaque, but is used to reduce the light intensity, the subject matter is not classified here but in subclass 889.
(2) Note. Class 359 provides for optical diaphragms and shutters, per se, in subclasses 227+ for lenses combined with shutters generally in subclasses 738+, and for lenses combined with diaphragms generally in subclasses 739+. However, a camera shutter and diaphragm, per se, are classifiable in Class 396, Photography, subclasses 452+ and subclasses 505+ respectively, the indicated use in cameras or camera background being sufficient for classification in Class 396 as opposed to Class 359. Class 396 also provides for lenses broadly or specifically combined with camera shutter or diaphragm details, it being emphasized that such combinations involving noncamera shutters or diaphragms or plural disclosures of utility are classified in subclasses 738+ and 739+ of Class 359 as indicated above. The combination of a lens broadly or specifically claimed and a camera shutter or diaphragm broadly claimed are classifiable in subclasses 738+ and 739+ of this class (359).

SEE OR SEARCH THIS CLASS, SUBCLASS:
196 for light deflection by a moving element.
738 for light controlling means combined with a lens.

SEE OR SEARCH CLASS:
396, Photography, particularly 452 and 505+ for shutters and diaphragms used in cameras and see (2) Note above.

Fluid:
This subclass is indented under subclass 227. Subject matter including a liquid or gas.
(1) Note. The fluid itself or an element in the fluid may constitute the light controlling element.

SEE OR SEARCH THIS CLASS, SUBCLASS:
296 for realignment or repositioning of particles (possibly opaque) suspended in a fluid in response to an applied field.
665 for a fluid lens.
886 for a fluid filter.

With glare or flicker elimination:
This subclass is indented under subclass 227. Subject matter comprising structure for equalizing light intensity reaching the eye or for reducing glare or flicker.

SEE OR SEARCH THIS CLASS, SUBCLASS:
601 for generic glare reduction.

Electro-mechanical:
This subclass is indented under subclass 227. Subject matter wherein electrical energy is used to control the movement of the light controlling element.
(1) Note. This includes solenoid and tuning fork structures and electrostatic type effects.

SEE OR SEARCH THIS CLASS, SUBCLASS:
228 for electro-mechanically controlled light control systems using a liquid.

String or ribbon type:
This subclass is indented under subclass 230. Subject matter wherein electric current is applied across a resilient, electrically conducting opaque element which as a result of its location in the field of an electromagnet vibrates, thus interrupting a light path or a portion thereof in accordance with variations in the current or in the strength of the field of the electromagnet.

Slit type:
This subclass is indented under subclass 227. Subject matter wherein the light controlling structure comprises a pair of jaws having opposed parallel edges which can be moved toward or away from each other and which can be fixed in a variety of intermediate positions between fully open and fully closed.
(1) Note. Typically the location of the center of the slit remains fixed.

With relative motion of two apertured elements:
This subclass is indented under subclass 227. Subject matter where the light control results from the relative movement of two opaque elements, each containing openings which allow light to pass.

With rotating or pivoting element (e.g., scanning discs):
This subclass is indented under subclass 227. Subject matter comprising means wherein the light control results from revolving, completely or partially, an opaque element or an element containing opaque and transparent portions.
(1) Note. Included here are generic optical shutters or diaphragms, per se, which have rotating vanes or blades.

SEE OR SEARCH THIS CLASS, SUBCLASS:
229 for similar subject matter used in reducing glare.
233 for two relative moving apertured elements which may rotate.

SEE OR SEARCH CLASS:
250, Radiant Energy, 201.1 for scanning elements of this type used in photo-cell controlled optical systems and subclass 232 for the combination of a light chopper and photocell.

Continuously rotating apertured element:
This subclass is indented under subclass 234. Subject matter wherein the light controlling element revolves nonstop during the operation of the device.
(1) Note. Apertures as used here encompass slots removed around the periphery of an otherwise opaque element.

SEE OR SEARCH THIS CLASS, SUBCLASS:
233 for relative motion of two apertured elements where one may be continuously rotating.

Element rotates about axis perpendicular to light path:
This subclass is indented under subclass 234. Subject matter wherein the light controlling element is revolved about an axis substantially at right angles to the direction of the light rays.

OPTICAL MODULATOR:
This subclass is indented under the class definition. Subject matter wherein an optical element varies a characteristic of a traversing optical light beam in direct proportion to an applied time-varying signal which may be in any energy form.
(1) Note. Characteristics of a traversing light beam that may be varied include its direction or characteristics such as amplitude, frequency, phase, or polarization.

SEE OR SEARCH THIS CLASS, SUBCLASS:
109 for optical communication systems or devices which may include an optical modulator.
325 for an optical demodulator, per se.

SEE OR SEARCH CLASS:
250, Radiant Energy, 200 for photocell circuit and subclasses 503.1+ for an invisible radiation source with a radiation modifying member, generally.
332, Modulators, appropriate subclasses for modulators of an electrical wave.
348, Television, 195 for mechanical-optical scanning.
352, Optics: Motion Pictures, subclass 84 for high speed cameras which use rotating optical elements and subclasses 105+ for motion picture optical rectifiers using roatating or scanning optical elements.
372, Coherent Light Generators, appropriate subclasses for lasers including internal light control apparatus.
385, Optical Waveguides, 1 and 4+ for light wave modulation within an optical waveguide.
396, Photography, particularly 452 and 505+ for shutters and diaphragms used in cameras and see (2) Note in subclass 227 above.

Light wave temporal modulation (e.g., frequency, amplitude, etc.):
This subclass is indented under subclass 237. Subject matter wherein a device varies a property of light which is a function of time only as it traverses the device where such variation is in accordance with the applied varying signal which can be of any energy form.
(1) Note. Such properties of the traversing light include amplitude, frequency, or phase.
(2) Note. Optical modulation occuring exclusively within a waveguide is classified in Class 385.

SEE OR SEARCH THIS CLASS, SUBCLASS:
298 for directional modulation.

SEE OR SEARCH CLASS:
385, Optical Waveguides, 1 for light temporal modulation inside of a waveguide.

Modulator output feedback to modulator:
This subclass is indented under subclass 238. Subject matter wherein the light beam output from the modulator is fed back into the modulator input.

Changing bulk optical parameter:
This subclass is indented under subclass 238. Subject matter comprising structure for controlling a light parameter by changing a bulk optical parameter of an optically transmitting medium.
(1) Note. "Bulk optical parameter" refers to those inherent internal characteristics of an optical element which can be defined by mathematical expressions describing their effect on light radiation (e.g., index of refraction, transmissivity, etc.) and which can be changed without producing a significant change in the shape, size, or contours of the optical element itself.
(2) Note. Included here are devices in which an optical parameter of the light control element is changed as a result of an applied electrical or magnetic field, an applied acoustic wave, a change in chemical structure, or by any other mechanism which primarily alters the bulk optical parameters rather than the physical shape, size, or contours of an optical medium.

SEE OR SEARCH THIS CLASS, SUBCLASS:
577 for light control by light interference.
738 for light controlling structure combined with a lens.

SEE OR SEARCH CLASS:
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, 48 and 84+ for selective electrical control of displays having light-controlling display elements.
372, Coherent Light Generators, appropriate subclasses for lasers including light control means.

By actinic radiation (e.g., photochromic):
This subclass is indented under subclass 240. Subject matter wherein an optical parameter of the light control element is changed by or in response to either the light to be controlled or a separate external source of optical radiation.

Display device:
This subclass is indented under subclass 241. Subject matter wherein the temporal modulation is in an information conveying element.

SEE OR SEARCH CLASS:
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, 1 for visual display systems with selective electrical control.

Bistable device:
This subclass is indented under subclass 241. Subject matter wherein an optical device has two distinct, stable output states which toggle between one another by a single application of actinic radiation.

Opto-optical device:
This subclass is indented under subclass 241. Subject matter wherein the temporal modulation is achieved by an externally applied modulating light wave.

Electro-optic:
This subclass is indented under subclass 240. Subject matter wherein the optical properties (e.g., index of refraction) of an optical element are changed in response to an applied electrical signal.

Modulation of polarized light via modulating input signal:
This subclass is indented under subclass 245. Subject matter wherein a property of a polarized optical beam, such as amplitude, phase, polarization, frequency, or color are varied in a controlled manner by the applied electrical signal.

Using reflective or cavity structure:
This subclass is indented under subclass 246. Subject matter wherein the modulation is effected by structure which redirects the entire beam or a part of the beam at an angle equal to that of incidence, or wherein the medium through which the beam passes is confined in a cavity.

SEE OR SEARCH THIS CLASS, SUBCLASS:
302 for reflecting structures used in beam deflection.

Semiconductor:
This subclass is indented under subclass 247. Subject matter wherein barrier layer (i.e., semiconducting) material is used in the modulating structure, generally, as a variable reflector.

Compensation technique:
This subclass is indented under subclass 246. Subject matter wherein unwanted effects due to the action of the medium or the field on the beam such as those due to temperature, birefringences, or color are eliminated.

SEE OR SEARCH THIS CLASS, SUBCLASS:
250 for plural mediums in the beam path where the plural mediums are not for the purpose of compensation.

Using plural mediums:
This subclass is indented under subclass 246. Subject matter wherein more than one medium or structure, each of which modulates the beam, are provided.
(1) Note. The mediums or structures in the beam path, layered mediums transverse to the beam path or parallel paths, each containing a medium where the output beam is the result of the combined action of the medium or structure.
Not all of the mediums need to be field responsive.
(2) Note. Initial polarizers and final analyzers are not considered part of the plural mediums where the only affect is to select a polarization. Plural areas formed by a matrix of electrodes whose sole function is to act on a portion of the beam are not considered plural mediums. Nonbirefringent lenses are also not considered a medium in the sense of the definition.

SEE OR SEARCH THIS CLASS, SUBCLASS:
249 for plural mediums where the purpose of the mediums is compensation.
301 for plural mediums used to deflect the beam or a portion of the beam.
497 for polarization achieved by plural birefringent elements.

With particular direction of the field in relation to the medium, beam direction or polarization:
This subclass is indented under subclass 246. Subject matter wherein details of the medium are given, especially crystal cut or orientation, and the direction of the applied field is specified in relation to the medium or in relation to the incident beam direction or polarization.

SEE OR SEARCH THIS CLASS, SUBCLASS:
252 for a particular medium where no field directional particulars, in relation to the medium, are specified.

With particular medium or state of the medium:
This subclass is indented under subclass 246. Subject matter wherein the details of the medium structure, state of the medium, shape of the medium, or treatment of the medium are recited.
(1) Note. For classification herein, there should be more than just the recitation of the name or abbreviation of the name of the material.

SEE OR SEARCH THIS CLASS, SUBCLASS:
251 where details of the medium are combined with a
particular field direction.
488 for a particular medium used for reflectively or refractively polarizing light.

SEE OR SEARCH CLASS:
23, Chemistry: Physical Processes, for preparation or treatment of nonmetallic elements involving only physical treatments.
252, Compositions, for compositions, per se.
264, Plastic and Nonmetallic Article Shaping or Treating: Processes, for melt shaping or treatment of nonmetallic materials.
423, Chemistry of Inorganic Compounds, for nonmetallic elements and for processes for producing nonmetallic elements involving a chemical reaction.

Liquid medium:
This subclass is indented under subclass 252. Subject matter wherein the medium is in a nongaseous fluid state.

SEE OR SEARCH THIS CLASS, SUBCLASS:
36 for similar structures using liquid crystals for the medium.

With particular electrode structure or arrangement, or medium mounting structure or arrangement:
This subclass is indented under subclass 246. Subject matter wherein the physical structure, geometry or arrangement of the electrodes is detailed or there is detailed mounting structure for the medium (e.g., to prevent physical distortion).
(1) Note. Included here are structures which perform auxiliary functions such as protection or index matching. Also, see subclasses 488 and 500.

SEE OR SEARCH THIS CLASS, SUBCLASS:
251 for the arrangement of the electrodes as related to the medium for a particular direction of the field in combination with details of the medium.
253 for those structures used with a liquid medium where the structure is peculiar to the medium.

SEE OR SEARCH CLASS:
310, Electrical Generator or Motor Structure, 365 for electrode arrangements with respect to a piezoelectric element.

With particular field:
This subclass is indented under subclass 246. Subject matter wherein the field which modulates the medium is of a specific magnitude, phase, or frequency or is of a specific type (e.g., pulse).

SEE OR SEARCH THIS CLASS, SUBCLASS:
251 for a field direction or polarization specified in relation to the medium (e.g., crystal cut).
484 for polarization by an applied magnetic field.

With birefringent element:
This subclass is indented under subclass 246. Subject matter including an element having the property of dividing a ray or beam of energy into two polarized rays or beams (known as the ordinary and extraordinary rays), the directions of polarization being at right angles to each other.
(1) Note. A birefringent material which has been treated with a dichroic dye to absorb the ordinary or extraordinary ray is no longer considered to be birefrin-gent within the meaning of this definition. A birefringent element in the form of a Nicol prism, where the unwanted ray is deflected, is classified here.

Pockel's cell:
This subclass is indented under subclass 246. Subject matter wherein the variation of a polarized light characteristic is achieved by an element which advances or retards the phase of an induced ordinary wave relative to the extraordinary wave
when the electrical signal is applied.

Kerr cell:
Subject matter under 246 wherein the variation of a polarized light characteristic is achieved by an element including a material (usually liquid) whose refractive index change is proportional to the square of the field of the applied electrical signal.

Plural modulation cells:
This subclass is indented under subclass 245. Subject matter wherein the temporal light modulator utilizes multiple elemental units each of which is electro-optically controlled.

Etalon structure:
This subclass is indented under subclass 245. Subject matter wherein the modulating structure consists of two parallel dielectric mirrors separated by an active electro-optic material.

Multiple reflections within cell:
This subclass is indented under subclass 245. Subject matter wherein the electro-optic temporal modulator includes plural internal redirections of the light passing therethrough.

Excitation by electron beam:
This subclass is indented under subclass 245. Subject matter wherein a collimated ray of electrons applied to the modulator is used to vary a temporal characteristic of the light passing therethrough.

By reflection:
This subclass is indented under subclass 245. Subject matter wherein the electro-optic temporal modulator includes a single internal redirection of the light passing therethrough.

Pulse Modulation:
This subclass is indented under subclass 245. Subject matter wherein a parameter of a train of optical pulses is varied in accordance with the amplitude of the applied signal.
(1) Note. Pulse modulation may involve changes in pulse amplitude (pam), pulse position (ppm), or pulse duration (pdm).
(2) Note. Pulse modulation includes pulse-code modulation wherein the light beam is transmitted as a digital binary code.
(3) Note. This subclass will include a combination of pulse modulation with amplitude, frequency, or phase modulation.

Electrochromic:
This subclass is indented under subclass 245. Subject matter wherein the electrical signal applied to the optical control element produces a color change in the element resulting in a change in the absorption characteristics of the element at a given wavelength of light.

SEE OR SEARCH CLASS:
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, subclass 49 and 105 for selective electrical control of displays having electrochromic display elements.
349, Liquid Crystal Cells, Elements and Systems, appropriate subclasses for liquid crystal light modulators.

Particular nonplanar electrode arrangement:
This subclass is indented under subclass 265. Subject matter wherein solid electrically conductive elements within the electrochromic device are not located on a single flat surface.

Reflection-type (e.g., display device):
This subclass is indented under subclass 265. Subject matter wherein the modulator utilizes a surface upon which light strikes and which is coated with a material that simultaneously changes color with the applied electrical signal and reflects a significant portion of incident light.

SEE OR SEARCH THIS CLASS, SUBCLASS:
275 for transmission-type (e.g., windows).

Complementary device:
This subclass is indented under subclass 267. Subject matter wherein an oxidizing material operates in conjunction with a reducing material.

Particular counter electrode:
This subclass is indented under subclass 267. Subject matter wherein details are recited of an electrode (the counter-electrode) which actually takes part in the electrochromic reaction.

Particular electrolyte layer:
This subclass is indented under subclass 267. Subject matter which recites details of an electrically conductive liquid layer which transports ions between the electrochromic material and the counter electrode.

Particular planar electrode pattern:
This subclass is indented under subclass 267. Subject matter including an electrically conductive solid element having a configuration which is uniformly flat.

Liquid cell:
This subclass is indented under subclass 267. Subject matter wherein the device comprises a cell containing a substance which is in a state intermediate that of a solid and a gas.

Particular electrochromic layer structure:
This subclass is indented under subclass 267. Subject matter which specifies details of the form of the electrochromic substance.

Diverse layer:
This subclass is indented under subclass 267. Subject matter including a specified miscellaneous layer within the reflection-type electrochromic device.
(1) Note. This might include, for example, an insulating layer.

Transmission-type (e.g., windows):
This subclass is indented under subclass 265. Subject matter wherein the modulator utilizes a surface upon which light strikes which is coated with a material that simultaneously changes color with the applied electrical signal and transmits a significant portion of incident light.

SEE OR SEARCH THIS CLASS, SUBCLASS:
267 for reflection-type (e.g., display device).

Amplitude modulation:
This subclass is indented under subclass 245. Subject matter wherein the amplitude of a constant frequency optical wave varies in synchronization with the amplitude of the applied signal (i.e., modulating signal).

SEE OR SEARCH THIS CLASS, SUBCLASS:
284 for magneto-optic amplitude modulation.
286 for acousto-optic amplitude modulation.
289 for thermal-optic amplitude modulation.

SEE OR SEARCH CLASS:
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, 48 and 84+ for selective electrical control of displays having light-controlling display elements.

Within display element:
This subclass is indented under subclass 276. Subject matter wherein the amplitude modulator is in an information conveying element.

SEE OR SEARCH CLASS:
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, 1 for visual display systems with selective electrical control.

Frequency modulation:
This subclass is indented under subclass 245. Subject matter wherein the frequency of a constant amplitude optical wave (i.e., carrier wave) varies in synchronization with the amplitude of the applied signal (i.e., modulating signal).

SEE OR SEARCH THIS CLASS, SUBCLASS:
287 for acousto-optic frequency modulation.

Phase modulation:
This subclass is indented under subclass 245. Subject matter wherein the normal zero phase of a constant amplitude optical wave (i.e., carrier wave) is shifted by an angle proportional to the amplitude of the applied signal (i.e., modulating signal).
(1) Note. A sinusoidal signal of zero phase will have a zero amplitude at the intersection of the x-y axis.

SEE OR SEARCH THIS CLASS, SUBCLASS:
278 for electro-optic frequency modulation.
287 for acousto-optic frequency modulation.

Magneto-optic:
This subclass is indented under subclass 240. Subject matter wherein a bulk optical parameter of an optical element is controlled by a magnetic signal applied to the element.

Modulation of polarized light via modulating input signal:
This subclass is indented under subclass 280. Subject matter wherein a property of a polarized optical beam, such as amplitude, phase, polarization, frequency, or color are varied in a controlled manner by the applied varying magnetic signal.

Using layered structure or plural mediums:
This subclass is indented under subclass 281. Subject matter wherein the structure through which the beam passes or is acted upon consists of more than one contiguous film or layer which forms a composite structure which modulates the beam or wherein there are plural mediums or structures in the beam path, each of which modulates the beam.
(1) Note. The composite structure can be dielectric or reflective films or layers for the purposes such as compensation, increased Kerr rotation or index (e.g., impedance) matching.

SEE OR SEARCH THIS CLASS, SUBCLASS:
250 for plural mediums where at least one medium is electric field responsive.
254 488 and 500, for layered structures where the purpose of the layers is for such things as protection or index matching..
487 for layered structure or plural mediums formed for polarization or beam-splitting purposes.
490 for layered structures formed with at least one layer of dichroic material where additional layers may be provided for purposes such as protection or particular bonding and for layered structures formed for interference effects.
497 for plural mediums including a birefringent medium which is not field responsive.

With particular direction of the field in relation to the medium, beam direction or polarization:
This subclass is indented under subclass 281. Subject matter wherein details of the medium are given, especially crystal cut or orientation, and the direction of the applied field is specified in relation to the medium or in relation to the incident beam direction or polarization.

SEE OR SEARCH THIS CLASS, SUBCLASS:
281 for magnetic modulating structures using a particular medium, state of the medium, particular electrode structure or arrangement, medium mounting structure or arrangement or with a particular field.

Amplitude modulation:
This subclass is indented under subclass 280. Subject matter wherein the amplitude of a constant frequency optical wave varies in synchronization with the amplitude of the applied signal (i.e., modulating signal).

SEE OR SEARCH THIS CLASS, SUBCLASS:
276 for electro-optic amplitude modulation.
286 for acousto-optic amplitude modulation.
289 for thermal-optic amplitude modulation.

Acousto-optic:
This subclass is indented under subclass 240. Subject matter wherein an ultrasonic wave generated at the surface or within the confines of the light control element sets up conditions in the element which produce a change in the optical parameters (e.g., refractive index) directly controlling the light.

Amplitude modulation:
This subclass is indented under subclass 285. Subject matter wherein the amplitude of a constant frequency optical wave varies in synchronization with the amplitude of the applied signal (i.e., modulating signal).

SEE OR SEARCH THIS CLASS, SUBCLASS:
276 for electro-optic amplitude modulation.
284 for magneto-optic amplitude modulation.
289 for thermal-optic amplitude modulation.

Frequency modulation:
This subclass is indented under subclass 285. Subject matter wherein the frequency of a constant amplitude optical wave (i.e., carrier wave) varies in synchronization with the amplitude of the applied signal (i.e., modulating signal).

SEE OR SEARCH THIS CLASS, SUBCLASS:
278 for electro-optic frequency modulation.

Thermo-optic:
This subclass is indented under subclass 240. Subject matter wherein optical properties (e.g., index of refraction) of an optical element are changed by or in response to applied heat.

Amplitude modulation:
This subclass is indented under subclass 288. Subject matter wherein the amplitude of a constant frequency optical wave varies in synchronization with the amplitude of the applied signal (i.e., modulating signal).

SEE OR SEARCH THIS CLASS, SUBCLASS:
276 for electro-optic amplitude modulation.
284 for magneto-optic amplitude modulation.
286 for acousto-optic amplitude modulation.

By changing physical characteristics (e.g., shape, size or contours) of an optical element:
This subclass is indented under subclass 238. Subject matter wherein the light property is controlled by a substantial alteration in the optical characteristics of a light control surface or interface or by changing the physical shape, position, or orientation of a light control surface or interface in response to the modulating signal.
(1) Note. Any change in or to the light control surface or interface occur wholly within the region of the light path in which control is effected. The control surface or interface is neither totally nor partially inserted into nor removed from the light path.

Shape or contour of light control surface altered:
This subclass is indented under subclass 290. Subject matter wherein the light property is controlled by means of a light control surface which is temporarily altered or modified in some way so as to produce distortions in the surface contours
which differ significantly from the normal or unmodified surface contours.

Light control surface forms image on projected light beam:
This subclass is indented under subclass 291. Subject matter wherein the contours of a light control surface are modified in accordance with a control signal so as to impart image or picture information to the contour of the control surface which is then transferred to a light beam projected on or through the control surface.

Electron beam causes surface alteration:
This subclass is indented under subclass 292. Subject matter wherein the light control surface is changed by a ray of electrons.

Using photoconductive layer:
This subclass is indented under subclass 291. Subject matter which utilizes a layer whose electrical conductivity varies as a function of light incident thereon.

Having multiple electrodes:
This subclass is indented under subclass 291. Subject matter which includes a plurality of solid electrically conducting elements.

Changing position or orientation of suspended particles:
This subclass is indented under subclass 290. Subject matter wherein the light control surface consists of a group of elongated light absorbing or reflecting particles suspended in a fluid media, which collectively change their orientation within the light path in response to an applied signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
228 for fluid light control elements.

Light control surface formed or destroyed:
This subclass is indented under subclass 290. Subject matter wherein a light property is controlled by creating or destroying a light absorbing or reflecting surface or interface in response to a modulating signal.

Light wave directional modulation (e.g., deflection or scanning is representative of the modulating signal):
This subclass is indented under subclass 237. Subject matter wherein the relative spatial orientation of a light wave exiting a device is changed in accordance with a varying signal of any energy form (i.e., modulating signal) applied to the device.
(1) Note. Optical directional modulation occuring exclusively inside of a waveguide is classified in Class 385.

SEE OR SEARCH THIS CLASS, SUBCLASS:
238 for light wave temporal modulation outside of a waveguide.

SEE OR SEARCH CLASS:
385, Optical Waveguides, 4 for optical directional modulation within an optical waveguide.

Opto-optical device:
This subclass is indented under subclass 298. Subject matter wherein the directional modulation is achieved by an externally applied modulating light wave.

Phase conjugate:
This subclass is indented under subclass 298. Subject matter including the return of a light beam through the media at precisely the same angles, distances, and intensities as prior to a reflection.

Acting on polarized light:
This subclass is indented under subclass 298. Subject matter wherein the direction of a polarized light beam is varied in accordance with a varying input signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
495 for beam deflection and splitting systems using birefringent elements.

Using reflecting or cavity structure:
This subclass is indented under subclass 301. Subject matter wherein the deflection is effected by structures which redirect the entire beam or a part of the beam at an angle equal to that of incidence or where the medium through which the beam passes is confined in a cavity.

SEE OR SEARCH THIS CLASS, SUBCLASS:
247 for reflecting structures used in beam temporal modulation.

Using more than one polarization (e.g., digital):
This subclass is indented under subclass 301. Subject matter wherein at least two distinct beams, corresponding to two different polarizations, are obtained.
(1) Note. The systems use a polarization modulation element to switch the polarization of the incoming beam followed by a birefringent polarization discriminator whereby two distinct beams are obtained corresponding to the ordinary and extraordinary rays.

SEE OR SEARCH THIS CLASS, SUBCLASS:
302 for reflecting structures where different polarizations are used.

Using single polarization:
This subclass is indented under subclass 301. Subject matter wherein the beam is given an initial polarization and then deflected or where only one polarization is allowed to be deflected by blocking or removing any other polarization component.

Acousto-optic:
This subclass is indented under subclass 298. Subject matter wherein directional modulation is achieved by applying a modulating sound wave to a device through which a light beam is traversing.

Correlation or convolution:
This subclass is indented under subclass 305. Subject matter wherein the correlation or convolution integral of two optical waves is formed by an acousto-optical directional modulator.

Utilizing optical feedback:
This subclass is indented under subclass 305. Subject matter wherein an acousto-optic modulator has a portion of the optical output therefrom returned to the input therefor.

Filter:
This subclass is indented under subclass 305. Subject matter wherein one frequency band present in an incident light beam is suppressed by an acousto-optic deflection technique.

Acting on polychromatic light:
This subclass is indented under subclass 305. Subject matter wherein directional modulation of a light wave which is a composite of many frequencies is achieved.

Plural cell array:
This subclass is indented under subclass 305. Subject matter wherein directional modulation is achieved by multiple acousto-optic devices.

Plural transducers on single cell:
This subclass is indented under subclass 305. Subject matter wherein the directional modulator consists of a single element having multiple input devices each capable of imposing a separate sound wave on the modulator.

Single transducer generating composite plural frequency acoustic wave:
This subclass is indented under subclass 305. Subject matter wherein a composite sound wave of diverse frequencies is generated and applied to the acousto-optic modulator.

Particular cell shape:
This subclass is indented under subclass 305. Subject matter wherein detailed structure of the overall configuration of the directional modulator is recited.

Particular cell orientation:
This subclass is indented under subclass 305. Subject matter wherein a specific location of the modulator relative to an incident light beam is recited.

Electro-optic:
This subclass is indented under subclass 298. Subject matter wherein directional modulation is achieved by applying a varying electrical signal to an element through which a light beam is traversing.

Plural modulation cells:
This subclass is indented under subclass 315. Subject matter wherein the directional light modulator utilizes multiple elemental units each of which is electro-optically controlled.

Multiple reflections within cell:
This subclass is indented under subclass 315. Subject matter wherein the electro-optic directional modulator includes plural internal redirections of the light passing therethrough.

By reflection:
This subclass is indented under subclass 315. Subject matter wherein the electro-optic directional modulator includes a single internal redirection of the light passing therethrough.

Focusing:
This subclass is indented under subclass 315. Subject matter wherein light beam focusing is achieved by the application of
the electrical signal to a device through which the beam transits.

Switching:
This subclass is indented under subclass 315. Subject matter wherein a discrete change in the path of a light beam is achieved by the application of the electrical signal to a device through which the beam transits

Having particular chemical composition or structure:
This subclass is indented under subclass 237. Subject matter wherein chemical details of an optical modulator are recited.

Electro-optic crystal material:
This subclass is indented under subclass 321. Subject matter wherein the material of the modulator is particularly responsive to an applied electrical signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
245 electro-optic light wave temporal modulation for changing bulk optical parameter.

PLZT material:
This subclass is indented under subclass 322. Subject matter wherein the material is a transparent lead-lanthanum zir- conate titanate ceramic with optical qualities that can be controlled by applying voltages to thin plates of the material.

Magneto-optic crystal material:
This subclass is indented under subclass 321. Subject matter wherein the material of the modulator is particularly responsive to an applied magnetic signal.

OPTICAL DEMODULATOR:
This subclass is indented under the class definition. Subject matter wherein an original modulating wave is recovered from a previously modulated light wave.
(1) Note. These devices may include a photodetector as long as a modulating wave is isolated.

SEE OR SEARCH THIS CLASS, SUBCLASS:
189 for optical communication receivers which include an optical demodulator.
237 for an optical modulator, per se.

SEE OR SEARCH CLASS:
250, Radiant Energy, 200 for photocell circuits and systems which convert light wave energy into electricity.
329, Demodulators, for electrical demodulators in general.

OPTICAL FREQUENCY CONVERTER:
This subclass is indented under the class definition. Subject matter wherein a nonlinear device alters the frequency of an applied traversing optical electromagnetic wave.
(1) Note. The frequencies here are quasi-optical (i.e., infrared through ultraviolet).
(2) Note. Such optical frequency devices include second harmonic generators and other types of frequency conversion devices such as downshifters, oscillators, mixers, etc.
(3) Note. A detailed optical frequency converter, per se, or such subject matter in combination with additional waveguide structure is classified in this class (359). However, the nominal recitation of any type of optical frequency converter together with additional waveguide structure is classified in Class 385, where such combination meets the class requirements.

SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, subclass 424 for a nonoptical parametric frequency converter.
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, 113 for miscellaneous frequency control.

Raman type:
This subclass is indented under subclass 326. Subject matter wherein the nonlinear optical device involves radiation-active materials in which many lines of frequency-shifted radiation can be obtained in response to incident radiation.
(1) Note. Raman radiation is a radiation produced in response to incident radiation by a change in the rotational or vibrational energy of scattering molecules. The resultant optical radiation is often referred to as Stokes or antiStokes radiation dependent upon its frequency relative to that of the incident light.

SEE OR SEARCH THIS CLASS, SUBCLASS:
334 for a Raman optical amplifier.

Harmonic generator:
This subclass is indented under subclass 326. Subject matter wherein a nonlinear optical device generates a wave having a frequency which is an integral multiple of a fundamental input wave frequency.
(1) Note. A wave with twice the frequency of the fundamental is called the second harmonic.

SEE OR SEARCH THIS CLASS, SUBCLASS:
240 for light wave temporal modulation via a nonlinear device.
255 for electro-optic polarization modulation by a nonlinear device.

SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, subclass 424 for a nonoptical parametric frequency converter.
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, 113 for miscellaneous frequency control such as electrical wave harmonic generation.
385, Optical Waveguides, subclass 122 for optical fiber waveguide with cladding having significant nonlinear property.

Third harmonic:
This subclass is indented under subclass 328. Subject matter wherein the generated optical wave has a frequency that is three times that of the fundamental input optical wave.

Parametric oscillator:
This subclass is indented under subclass 326. Subject matter wherein the frequency conversion of electromagnetic radiation, in the near and the visible spectrum, is based on the nonlinear dependence of polarizability on wave amplitude.
(1) Note. A parametric oscillation is an oscillation in which substantial power is applied at a frequency called the pump frequency. Signal and idler waves, the sum of whose frequencies equals the pump frequency, are generated in an interaction resulting from some nonlinear effect in the optical crystal.

Optical laser acoustic delay line type:
This subclass is indented under subclass 326. Subject matter wherein the output from a laser is mode-locked and passed through an acoustic cell in which a radio frequency acoustic wave has been generated; the laser beam is diffracted, and one of the frequency shifted diffracted modes is heterodyned at a detector with an unshifted mode to produce a time delayed radio frequency output signal lower in frequency than the input signal.

Dielectric optical waveguide type:
This subclass is indented under subclass 326. Subject matter wherein the depletion layer of a semiconductor whose dielectric material exhibits nonlinear susceptibility is used as an optical waveguide to achieve frequency translation.

SEE OR SEARCH CLASS:
374, Thermal Measuring and Testing, subclass 177 for an electrical thermometer having a ferroelectric sensor.
385, Optical Waveguides, 129 for a planar optical waveguide.

OPTICAL AMPLIFIER:
This subclass is indented under the class definition. Subject matter wherein the amplifying device produces an output light beam which is only changed to increase the magnitude of a light beam applied as input.
(1) Note. This amplification can be produced by applying electrical energy to the device to first cause excitation to a higher energy level via certain molecular, atomic, or nuclear particles of a substance and later causing the high energy state to be relaxed to a lower state to produce the emission of the particles.
(2) Note. This amplifcation is the optical or quasi-optical wavelength range, which is generally in the range from ultra-violet (100 Angstroms) to far infrared (10 million Angstroms) of the optical spectrum. See (1) Note of subclass 350 for specific IR and UV wavelength units.
(3) Note. This subclass necessitates light input into a medium prior to amplification. Production of a light beam output without an input light beam is classified in Class 372.
(4) Note. This subclass includes details of an optical amplifier wherein amplification is produced within the optical fiber by the interaction of externally applied energy and a unique property of the fiber (e.g., lazing material). The mere nominal recitation of an optical amplifier in combination with an optical waveguide structure is classified in Class 385.
(5) Note. Infrared to Ultraviolet light emitting junction is classified in Class 357, subclass 17, unless a cavity is
set forth for Class 372 or amplification is set forth for this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
109 for optical communication.
237 for optical modulators external to an optical fiber.
326 for optical frequency translators.
341 for details of an optical amplier wherein amplification is produced within the fiber optics, wherein the optical fiber has some unique property (i.e., lasing material), to produce the amplification when external energy is applied.

SEE OR SEARCH CLASS:
219, Electric Heating, 121.6 for metal heating by arc using a laser.
250, Radiant Energy, 200 for photocells, circuits and apparatus, and subclasses 552+ for solid state light emitting source which is detected by a photocell.
257, Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), subclasses 80-85 for incoherent light emitting devices combined with, or also constituting a light responsive device.
313, Electric Lamp and Discharge Devices, subclass 371 for a cathode-ray tube with optics and subclass 372 for a cathode-ray tube with light conducting fiber or rod.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation), subclass 53 for the combination with an infrared device, and subclass 54 for the combination with a laser.
348, Television, subclass 217 and 300 for camera with image intensifier or amplifier, subclass 707 for television amplifier circuit and subclass 777 for cathode-ray tube image source with intensifier.
351, Optics: Eye Examinating, Vision Testing, and Correcting, subclass 213 including light filter or absorber, subclass 214 including diaphragm or slit, and subclass 215 including light polarizing.
356, Optics: Measuring and Testing, 300 for dispersed light spectroscopy.
362, Illumination, subclass 32 for light fibers, rods or pipes, subclass 259 for laser type light source (or support therefor) and modifier, and subclasses 317+ for light modifier.
365, Static Information Storage and Retrieval, subclass 108 for liquid crystal memory and subclasses 120+ for information masking using polarization, Bragg cells, diffraction, holograms electron beams, etc.
369, Dynamic Information Storage or Retrieval, subclass 110 where the information is stored or retrieved from the medium by polarized radiant energy subclass 116 where the information is stored or retrieved from the medium by light intensity adjustment or maintenance and subclass 117 where the information is stored or retrieved from the medium by a movable shutter or light gate.
372, Coherent Light Generators, for lasers and optical oscillators wherein a light output beam is generated without the application of a light input beam.
376, Induced Nuclear Reactions: Processes, Systems, and Elements, subclass 103 for photon beam (e.g., laser) irradiation nuclear fusion, subclass 104 for optics nuclear fusion, and subclass 105 for particle beam irradiation (excluding photons) nuclear fusion.
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems, subclass 102 for bistable electro - optical devices.
385, Optical Waveguides, 1 for temporal optical modulation produced within the fiber, and subclasses 4+ for directional modulation produced within the fiber. Class 385 contains patents claiming optical modulation within the fiber but optical amplification (333+) or frequency translation (326+) within the fiber are specifially excluded from Class 385, unless the amplifier or frequency translator are only nominally set forth.
427, Coating Processes, 163.1 for processes of coating an optical polarizer, windshield, fiber, waveguide, rod, projection screen, or retroreflector.
430, Radiation Imagery Chemistry: Process, Composition, or Product Thereof, subclass 363 for laser or radiation color imaging exposure other than visible light and subclass 945 for laser beam cross-reference art collection.

Raman or Brillouin process:
This subclass is indented under subclass 333. Subject matter wherein the scattered light beam output from a medium, resulting from either the Raman or Brillouin effects, is amplified relative to the input to the medium.
(1) Note. The Raman effect claimed specifically for the
optical amplification properties is classified in this subclass, whereas the Raman effect claimed for the frequency translation by itself or together with optical amplification is classified in subclass 327.
(2) Note. Stimulated Raman effect is the amplification exhibiting the characteristic of stimulated emission of the small portion of light that is scattered in random directions when a monochromatic light beam of high intensity is transmitted through matter. The characteristic of the small portion of light is related to the frequencies of the matter.
(3) Note. The Raman effect results in the re-radiation of light from a bombarded molecule, having a longer wavelength than the original bombaring beam of coherent light. Part of the energy of the coherent beam is distributed throughout the molecule whereas the remaining energy is re-radiated. This effect may be described as being feeble, instantaneous, independent of absorption, independent of the wavelength of the exciting radiation; and it results in the re-emission of light generally having a wavelength longer than the existing one. Although there is a difference in wavelengths or frequency between the wavelengths of each re-emitted spectral line, or Raman line, and the wavelength of the incident or exciting radiation; the intensity of Raman increases as the fourth power of the incident frequency except in the neighborhood of an absorption band, where the scattering intensity increases still more markedly.
(4) Note. Brillouin scattering is the nonlinear optical phenomenon of the spontaneous scattering of light in a medium by its interaction with sound waves passing through the medium

SEE OR SEARCH THIS CLASS, SUBCLASS:
327 for Raman type frequency translators.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, subclass 3 for Raman lasers without a light input beam.

Free electron:
This subclass is indented under subclass 333. Subject matter wherein a beam of "free" and unbound electrons of an atom or molecule are passed through an undulator (i.e., "wiggler"), which creates a magnetic field of alternating polarity, to cause the electrons to move along a helical path (i.e., "wiggle") for the release of a high power light radiation (i.e., amplification of the light input beam).
(1) Note. The use of a free-electron laser for light amplificatoin belongs in this subclass.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, subclass 2 for free electron lasers and subclass 74 for electron beam pumping without a light input beam.

Bistable:
This subclass is indented under subclass 333. Subject matter wherein a two level output is produced (i.e., an amplified output or no output at all) dependent upon the specific characteristic (e.g., amplitude or frequency) of the input light beam that the amplifier is designed to amplify.
(1) Note. The specific type of amplifier (i.e., material type, cavity structure, resonant cavity length, leachable material, etc.) determines which input signal characteristic will produce an amplified output. All other inputs will result in a zero output.

SEE OR SEARCH CLASS:
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems, subclass 102 using bistable electro-optical devices.

Correction of deleterious effects:
This subclass is indented under subclass 333. Subject matter wherein an amplifier is corrected to overcome actions that prohibit its proper operation.
(1) Note. In order to overcome laser overheating, extraneous gasses that prohibit population inversion, laser medium losing energy that would deplete energy, an excess of power density, etc., the correction is applied to the optical amplifier itself.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, subclass 33 for particular operating compensation.

Using phase conjugation:
This subclass is indented under subclass 337. Subject matter wherein the light beam returns through the medium at precisely the same angles, distances, and intensities it was directed prior to the reflection.
(1) Note. The medium causes the light to return to its origin after reflection in precisely the same identical path it took to reach the reflector.
(2) Note. See the January 1986 Scientific American article on this subject matter.
(3) Note. This is often used to clear up poor images.

SEE OR SEARCH THIS CLASS, SUBCLASS:
300 for phase conjugate light wave directional modulation (e.g., deflection or scanning).

Using saturable or spatial filter:
This subclass is indented under subclass 337. Subject matter wherein the correction is accomplished by allowing light transmission through the filter of an input light beam only after a particular amount of energy is either applied (saturable filter) or a specific portion of the light beam is passed (spatial filter).
(1) Note. A saturable filber is opaque to a light beam input until one of the atoms of its material is excited to a second energy level as a result of striking photons. Upon reaching this second energy level, the filter becomes "saturated" and thus transparent to the input beam due to the equalization between the original and second energy levels causing no net absorption of additional photons as they strike the filter.
(2) Note. A spatial filter generally consists of either (a) an emulsion mask having a clean annular region in an otherwise opaque region or (b) a pinhole, placed at a focal plane in a laser expander; to remove unwanted radiation generally referred to as amplified spontaneous emission.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, subclass 11 for absorption filter Q-Switch and subclass 14 for mechanical spatial filter Q-Switch.

Mode locked:
This subclass is indented under subclass 333. Subject matter wherein the energy content of each state (i.e., mode) of an oscillating system (e.g., laser) is internally modulated in a particular field pattern and is one of the possible resonant frequencies of the system to selectively give rise to energy bursts of high peak power and short duration which can be in the picosecond domain.
(1) Note. This laser, referred to as a mode-locked laser could also be in a continuous wave mode or a pulsed mode.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, subclass 18 for mode locking particular beam control without a light input beam.

Optical fiber:
This subclass is indented under subclass 333. Subject matter wherein amplification is produced within the optical fiber by the interaction of externally applied energy and a unique property of the fiber (e.g., lasing material).
(1) Note. The details of an optical amplifier within an optical waveguide or combination with additional external waveguide structure are classified in this subclass.
(2) Note. Optical waveguides or fibers having the amplification performed within the waveguide of fiber are classified in this subclass.
(3) Note. Class 385 contains patents claiming optical modulation within the fiber but optical amplification (subclasses 333+) or frequency translation (subclasses 326+) within the fiber are specifically excluded from Class 385, unless the amplifier or frequency translator are only nominally set forth.

SEE OR SEARCH THIS CLASS, SUBCLASS:
332 for optical waveguides which produce frequency translation.

SEE OR SEARCH CLASS:
385, Optical Waveguides, 1 for temporal modulation performed within the optical waveguides and subclasses 4+ for
directional modulation performed within the optical waveguide.

Particular active medium (e.g., crystal, plasma, fluid, etc.):
This subclass is indented under subclass 333. Subject matter wherein a specified type of active medium, which uniquely causes the amplification of the light input, is used to change the number of atoms or atomic system in a set of energy levels as a result of the absorption of light incident on the material of the medium.
(1) Note. The examples of crystal, plasma, and fluid define the physical state of the active medium.

SEE OR SEARCH THIS CLASS, SUBCLASS:
343 for a glass (amorphous) medium.
344 for a semiconductor medium.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, 39 for a particular active medium which is not used for amplification of a light beam input.

Glass (amorphous):
This subclass is indented under subclass 342. Subject matter wherein the solid active medium does not have a definite crystalline structure.

SEE OR SEARCH THIS CLASS, SUBCLASS:
342 for crystal, plasma, fluid, etc., active medium.
344 for a semiconductor medium.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, subclass 40 for an amorphous (e.g., glass) active medium which is not used to amplify a light beam input.

Semiconductor:
This subclass is indented under subclass 342. Subject matter wherein the active medium is a solid or liquid having a resistivity midway between that of an insulator and a metal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
342 for crystal, plasma, fluid, etc., active medium.
343 for a glass (amorphous) medium.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, 43 for a semiconductor active medium which is not used for amplification of a light beam input.

Particular pumping type (e.g., electrical, optical, nuclear, magnetic, etc.):
This subclass is indented under subclass 333. Subject matter wherein a specified type of pumping is used to change the number of atoms or atomic system in a set of energy levels as a result of the absorption of light incident on the material.
(1) Note. This pumping causes the atoms of a medium to be raised from certain lower to certain higher energy levels, and it may cause a population inversion between certain intermediate levels in order to ultimately produce photons when the energy level moves from higher to lower.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, 69 for particular pumping type which is not used for amplification of a light beam input.

Particular resonator cavity (e.g., scanning, confocal or folded mirrors, etc.):
This subclass is indented under subclass 333. Subject matter wherein the optical beam goes back and forth within an optical cavity without any standing waves, similar to an oscillating cavity, but resulting in the amplification of the light input beam.
(1) Note. This can be a mode-selecting high gain optical structure in which the laser action takes place by the build-up of electromagnetic field intensity upon multiple reflections.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, 92 for laser particular resonant cavities which are not used for amplification of a light beam input.

Multiple pass:
This subclass is indented under subclass 333. Subject matter wherein the laser material does not have to be continually pumped since the laser stays in a lasing state for multiple traverses of light throughout the lasing medium to produce amplified light beams that last longer than the period for the pumping itself.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, subclass 350 for ring lasers with interfering different frequency beams.
372, Coherent Light Generators, subclass 94 for ring configuration folded resonant cavity.

Regenerative:
This subclass is indented under subclass 347. Subject matter wherein the lasing medium is pumped more than once to amplify a single input pulse.

SEE OR SEARCH CLASS:
372, Coherent Light Generators, 69 for particular pumping.

Beam combination or separation:
This subclass is indented under subclass 333. Subject matter wherein a light beam is either combined with another light beam or many light beams are created from a single light beam in order to produce the desired amplification.

HAVING SIGNIFICANT INFRARED OR ULTRAVIOLET PROPERTY:
This subclass is indented under the class definition. Subject matter including structure which is specifically adapted, as by structure or composition, to function as an optical element in the infrared (IR) or ultraviolet (UV) portion of the spectrum, or wherein an optical element is constructed or composed to extend its operation into the infrared or ultraviolet from the visible portion of the spectrum.
(1) Note. IR (0.7 micrometers to 1000 micrometers wavelength) according to Van Nostrand's Encyclopedia, 7th Edition
Meters: 7 X 10[supscrpt]-7[end supscrpt] m to .001 m
Centimeters: 7 X 10[supscrpt]-5[end supscrpt] cm to .1 cm
Millimeters: 7 X 10[supscrpt]-4[end supscrpt] mm to 1 mm
Micrometers: .7 micrometers to 1000
micrometers
Nanometers: 700 nm to 10[supscrpt]6[end supscrpt] nm
Angstroms: 7000 A to 10[supscrpt]7[end supscrpt] A
UV (100 Angstroms to 4000 Angstroms wavelength) according to Van Nostrand's Encyclopedia, 7th Edition
Meters: 10[supscrpt]-8[end supscrpt] m to 4 X 10[supscrpt]-7[end supscrpt] m
Centimeters: 10[supscrpt]-6[end supscrpt] cm to 4 X 10[supscrpt]-5[end supscrpt] cm
Millimeters: 10[supscrpt]-5[end supscrpt] mm to 4 X 10[supscrpt]-4[end supscrpt] mm
Micrometers: .01 micrometers to .4
micrometers
Nanometers: 10 nm to 400 nm
Angstroms: 100 A to 4000 A
Metric Conversion Units:
Centimeters = 10[supscrpt]-2[end supscrpt] meters
Millimeters = 10[supscrpt]-3[end supscrpt] meters
Micrometers = 10[supscrpt]-6[end supscrpt] meters
Nanometers = 10[supscrpt]-9[end supscrpt] meters
Angstroms = 10[supscrpt]-10[end supscrpt] meters
(2) Note. Holos:graphic systems and modulators of Class 359 and fibers or waveguides of Class 385 that operate in the IR or UV portion of the spectrum are excluded from this and the indented subclasses.
(3) Note. This subclass and those indented thereunder are limited to elements which operate as optical elements in the infrared and ultraviolet portion of the spectrum but a detector to convert IR/UV energy to visible light is classified in Class 250.
(4) Note. "Heat Filters" are considered infrared filters.

SEE OR SEARCH THIS CLASS, SUBCLASS:
358 for IR or UV fluid filter or fluid mirror.
634 for wavelength selective beam splitting or combining surface (e.g., dichroic mirror).
859 for concave and convex mirrors in series for successive reflections in mirrors.
885 for absorption filters.

SEE OR SEARCH CLASS:
89, Ordnance, subclass 41.06 for light reception traning mechanism.
165, Heat Exchange, 279 for temperature or pressure automatic control (Thermal-IR).
219, Electric Heating, subclass 203 for combined vehicle or vehicle component windshield or window heating device.
250, Radiant Energy, subclass 216 for optical or pre-optical photocell system, subclass 226 for color filter or spectroscope optical or pre-photocell system, subclasses 330+ for infrared-to-visible imaging, subclass 333 image tube type imaging wherein the output screen is used to visualize an intensified image or the IR image is converted to electrical signals to control the display device, subclass 336.1 for IR energy responsive electric signalling, subclasses 338.1+ for
infrared responsive invisible radiant energy responsive electric signalling, subclass 351 for periodic scanning of an IR beam, subclass 365 for UV light source, subclass 372 for UV light responsive means, subclass 493.1 for radiant energy generation and sources, subclass 504 for ultraviolet or infrared source radiation modifying member, and subclasses 505.1+ for radiation controlling elements exclusive of infrared, visible and ultraviolet optical elements.
252, Compositions, subclass 587 for infrared light transmission modifying compositions, and subclasses 588+ for ultraviolet transmission modifying compositions.
283, Printed Matter, subclass 88 for IR filter with electromagnetic radiation having revealable concealed information, fraud preventer or detector, use preventer or detector, or identifier, subclass 89 for UV filter with electromagnetic radiation having revealable concealed information, fraud preventer or detector, use preventer or detector, or identifier, and subclass 90 for polarized IR filter with electromagnetic radiation having revealable concealed information, fraud preventer or detector, use preventer or detector, or identifier.
313, Electric Lamp and Discharge Devices, subclass 112 for polarizer or special ray transmission with optical device or special ray transmission envelope.
348, Television, 164 for IR television.
351, Optics: Eye Examining, Vision Testing and Correcting, 44 for antiglare or shading spectacles and eyeglasses, and subclass 163 for light filtering opthalmic lens or blanks.
352, Optics: Motion Pictures, subclass 202 for projection light sources with cooling means.
353, Optics: Image Projectors, subclass 55 for an image projector having a heat filter.
356, Optics: Measuring and Testing, subclass 51 for IR and UV.
374, Thermal Measuring and Testing, subclass 124 for thermally emitted radiation with scanning or temperature distribution display.
424, Drug, Bio-Affecting and Body Treating Compositions, 59 for a sun or radiation screening or suntanning composition intended for topical application to a living body.
427, Coating Processes, subclass 160 for a coating with X-ray, Ultrasonic, or Infrared properties, subclasses 162+ for coating processes, per se, wherein the product is an optical element.
607, Surgery: Light, Thermal, and Electrical Application,
subclass 1 for light, thermal, and electrically applied surgery.

Having folded optical path:
This subclass is indented under subclass 350. Subject matter including an element which modifies the path of incident light so as to cause the light to repeatedly traverse the same or overlapping volumes of space.
(1) Note. The system generally includes plural reflectors to sequentially reverse the direction of the optical axis.

SEE OR SEARCH THIS CLASS, SUBCLASS:
495 for birefringent element beam deflection or splitting for polarization without modulation or external input.

Having polarizing element:
This subclass is indented under subclass 350. Subject matter having an element which restricts the direction of vibration of radiant energy.
(1) Note. The restriction may have a time variation.
(2) Note. The polarized radiant energy may be visible light accompanying the infrared or ultraviolet radiation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
359 for an IR/UV multilayer filter or multilayer reflector.
360 for an IR/UV multilayer filter or multilayer reflector having a metal layer.
372 for plural optical axis microscope.
419 for plural optical axis telescope.
483 for a visible light polarizer absent any infrared or ultraviolet characteristic.
486 for light polarization without modulation or external energy by grid or dipoles.
487 for polarization without modulation by reflection or refraction.
490 for polarization without modulation by dichroic medium, which transmits light of one color and reflects light of the complementary color with little light absorbed.
494 for polarization without modulation by a birefringent element, which divides a ray or beam of energy into two polarized rays or beams separated by 90 degrees (known as ordinary and extraordinary).

SEE OR SEARCH CLASS:
283, Printed Matter, subclass 88 for IR filter with electromagnetic radiation having revealable concealed information, fraud preventer or detector, use preventer or detector, or identifier.
313, Electric Lamp and Discharge Devices, subclass 112 for polarizer or special ray transmission (e.g., filter) with an electric discharge device.

Including alternative optical path or optical element (e.g., day-night, hi-low magnification):
This subclass is indented under subclass 350. Subject matter which has an element allowing a variable radiation path or which alternatively places an optical element into or out of a fixed optical path, thereby producing plural distinct radiation processing configurations.
(1) Note. One or more configurations may be limited to visible light.

SEE OR SEARCH THIS CLASS, SUBCLASS:
421 for telescope compound lens selectable magnification.
672 for lens with selective magnification by exchanging or adding lens components.
708 for aspherical lens.
744 for afocal Galilean telescope lens.

Including continuously variable magnification or focal length (zoom lens, adjustable lens):
This subclass is indented under subclass 350. Subject matter wherein the focal point or image magnification of an imaging device or element is continuously or intermittantly changed
as desired.
(1) Note. This includes various selected positions of different optical elements to fit the user selected application.
(2) Note. This incudes IR/UV variable elements adjacent to or part of the zoom lens.
(3) Note. This also includes FLIR (Forward Looking Infrared systems).

SEE OR SEARCH THIS CLASS, SUBCLASS:
421 for telescope selectable magnification in a compound lens for the visible portion of the spectrum.
422 for telescope variable magnification in a compound lens for the visible portion of the spectrum.
676 for zoom lens in the visible portion of the spectrum.
744 for an afocal lens (e.g., Galilean Telescope).

Lens, lens system or component:
This subclass is indented under subclass 350. Subject matter including a refractive imaging element or a serially arranged group thereof having a significant property in the infrared or ultraviolet area of the electromagnetic spectrum.
(1) Note. Compound lens systems are a plurality of lenses or lens groups arranged in series coaxially along an optical axis, such lenses or lens groups being so spaced along the axis that the second focal plane of the entrant lens of the series lies at or near the first focal plane of the next succeeding lens or lens group of the series whereby the light entrant lens is capable of producing from light rays passing therethrough from an object external to the plurality of lenses an image of that object, which image is viewed or relayed by the said succeeding lens or lens group.
(2) Note. Lens systems designate either a single transparent mass of refractive material having opposed refracting surfaces or a plurality of such masses arranged in series along an optical axis with their opposed refracting surfaces disposed transversely of such axis, the said opposed surfaces being so shaped and spaced that the mass or plurality of masses are capable of producing from light rays passing therethrough from an object external to the mass or masses a single image of that object, which image is also external to the mass or masses of material.
(3) Note. The term "component" as applied to a lens designates either a single transparent mass of refractive material having two opposed refracting surfaces or a grouped plurality of such masses arranged in series along the optical axis of the lens with their adjacent refracting surfaces either in full over-all contact or in spaced parallel relation with the spacing being of such small magnitude that it does not enter into the lens computations, the two refracting surfaces of the single mass and the two axially extreme refracting surfaces of the plurality of masses having at least a portion thereof axially air spaced from all other adjacent refracting surfaces that may be present in the lens. The axial dimension of the air spacing between either the opposed surfaces of the single mass or the axially extreme surfaces of the grouped plurality of masses and the other adjacent refracting surfaces that may be present in the lens must be of sufficient magnitude to enter into the lens computations in order to limit the axial extent of the lens component.

SEE OR SEARCH THIS CLASS, SUBCLASS:
356 for an infrared lens.
357 for an infrared lens having four or more components.
642 for lenses in the visible portion of the spectrum.
722 for lenses which are selective in the visible spectrum by transmitting or blocking certain wavelengths.

SEE OR SEARCH CLASS:
427, Coating Processes, subclass 160 for a coating having X-ray, ultraviolet, or infrared properties.

Infrared lens:
This subclass is indented under subclass 355. Subject matter having significant properties in the infrared area of the electromagnetic spectrum.

Having four or more components:
This subclass is indented under subclass 356. Subject matter which includes four or more components which have significant properties in the infrared area of the electromagnetic spectrum.

SEE OR SEARCH THIS CLASS, SUBCLASS:
754 for multiple component lenses, in general.

Fluid filter or fluid mirror:
This subclass is indented under subclass 350. Subject matter including filters or mirrors having a liquid or gas which is specially adapted as by composition to transmit or absorb infrared or ultraviolet radiation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
665 for fluid lenses.
832 for fluid filled prisms.
845 for fluid cooled mirrors.
886 for fluid absorption filters which operate in the visible portion of the spectrum.

SEE OR SEARCH CLASS:
250, Radiant Energy, subclass 226 for color filter or spectroscope optical or pre-photocell system.
252, Compositions, 582 for light transmission modifying compositions and subclass 588 for those compositions used for ultraviolet light transmission modifying.

Multilayer filter or multilayer reflector:
This subclass is indented under subclass 350. Subject matter having a substrate and one or more superimposed coatings or laminae and which as a whole is designed to have significant absorbent or redirective properties in the infrared or ultraviolet portion of the spectrum.
(1) Note. Interference filters wherein the multiple reflected beams of various different frequencies will automatically interfere with one another upon reflection are classified in this subclass if significant IR/UV is specified.
(2) Note. Multi-layer absorption would not be interference since waves are not produced which interfere with one another.
(3) Note. Multi-layer absorbing elements are classifed in this subclass if significant IR/UV is specified.
(4) Note. Semiconductor elements are classifed in this subclass since they are not considered metals for subclass 360.

SEE OR SEARCH THIS CLASS, SUBCLASS:
580 for light interference produced by coating or lamina.
581 for transmissive coating on interference lens.
589 for selective wavelength interference.
590 for selective wavelength interference with another filter.
839 for mirrors with a transmissive property.
884 for mirrors with a selective absorption or transparent overcoating.
885 for absorptive filters.

SEE OR SEARCH CLASS:
204, Chemistry: Electrical and Wave Energy, 192.26 for optical or photoactive specified deposition material glow discharge sputter deposited coating.

Having metal layer:
This subclass is indented under subclass 359. Subject matter wherein at least one coating or lamina or the substrate is composed of a metal.
(1) Note. Semiconductor elements are not considered as metal and are included under subclass 359.
(2) Note. Only an elemental metal layer is classified in this subclass. Metal alloys or compositions in a multilayer structure are classified in subclass 359.

SEE OR SEARCH THIS CLASS, SUBCLASS:
722 for lenses with selective wavelength transmitting or blocking.

SEE OR SEARCH CLASS:
250, Radiant Energy, subclass 226 for color filter or spectroscope optical or pre-photocell system.
351, Optics: Eye Examining, Vision Testing and Correcting, subclass 44 for sunglasses with antiglare or shading.
607, Surgery: Light, Thermal, and Electrical Application, subclass 95 for solar cabinets.

Having ultraviolet absorbing or shielding property:
This subclass is indented under subclass 350. Subject matter wherein light in the ultraviolet portion of the spectrum is blocked or otherwise filtered.

SEE OR SEARCH THIS CLASS, SUBCLASS:
359 for a multilayer ultraviolet filter.

COMPOUND LENS SYSTEM:
This subclass is indented under the class definition. Subject matter including a plurality of image formers arranged for forming a series of real images along the optical axis, at least one of the real images being formed between two of the image formers.
(1) Note. The terminal image former may be an "eyepiece" designed to form a real image only in combination with the human eye.

SEE OR SEARCH THIS CLASS, SUBCLASS:
642 for lenses suitable for use in compound lens systems of this subclass type.

SEE OR SEARCH CLASS:
33, Geometrical Instruments, 245 for compound lens systems combined with firearms.
356, Optics: Measuring and Testing, 245 for optical test instruments containing compound lens systems.

With image recorder:
This subclass is indented under subclass 362. Subject matter
including a device to record an image of the object being directly viewed, the compound lens system being primarily designed for direct viewing.

SEE OR SEARCH THIS CLASS, SUBCLASS:
372 for a microscope with plural optical axes, one axis of which may be directed to an image recorder.
403 for a periscope with plural optical axes, one axis of which may be directed to an image recorder.
419 for a telescope with plural optical axes, one axis of which may be directed to an image recorder.

SEE OR SEARCH CLASS:
396, Photography, subclass 432 for significant camera structure combined with a diverse compound lens system.

With curved reflective imaging element:
This subclass is indented under subclass 362. Subject matter including a curved reflector which contributes to the formation of at least one of the real images.

SEE OR SEARCH THIS CLASS, SUBCLASS:
727 for lenses that employ both refraction and reflection in forming an image (catadioptric lenses).

SEE OR SEARCH CLASS:
362, Illumination, 296 for reflectors in illumination systems.

Two or more in a series:
This subclass is indented under subclass 364. Subject matter including a plurality of curved reflectors contributing to the formation of one or more of the real images.

SEE OR SEARCH THIS CLASS, SUBCLASS:
858 for image forming reflectors having plural curved surfaces in series.

Concave, convex combination:
This subclass is indented under subclass 365. Subject matter wherein the plurality of curved reflectors include at least one concave and at least one convex reflector.

Right angle inspector:
This subclass is indented under subclass 362. Subject matter including a compound lens system with an objective deflector to provide viewing at a right angle to the main optical axis.

SEE OR SEARCH THIS CLASS, SUBCLASS:
434 for a relay system which may be used in a compound lens system of the structure classified in this subclass (367).

Microscope:
This subclass is indented under subclass 362. Subject matter wherein the objective of the compound lens system is designed to focus highly divergent light from an object very close to the objective.
(1) Note. Also illuminators, stages, slide carriers, and transparent slides designed specifically for use with that type of compound lens system are classified in subclasses indented under this subclass (368).

With viewed screen:
This subclass is indented under subclass 368. Subject matter including structure for displaying a real image on a viewed screen.
(1) Note. The screen may be at an intermediate or terminal image plane and may, for example, comprise a ground glass screen, a front projection screen, a fiber optic output face, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:
400 for a telescope with a viewed screen.
443 for a viewing screen.
505 for an extended spacing structure for optical elements including a screen.

SEE OR SEARCH CLASS:
250, Radiant Energy, 370.08 for invisible radiant energy responsive signalling, including imaging.
313, Electric Lamp and Discharge Devices, 364 for cathode-ray tubes and subclasses 523+ for image intensifier tubes, etc.
315, Electric Lamp and Discharge Devices: Systems, 1 for cathode-ray tube circuits, including image intensifiers.
353, Optics: Image Projectors, subclass 18, 47, 67, 72+, 74+, and 79+ for an image projection and viewing screen in combination.

Interference:
This subclass is indented under subclass 368. Subject matter wherein light from the object is combined with light of different phase or diffraction characteristics either from the object or bypassing the object.

SEE OR SEARCH THIS CLASS, SUBCLASS:
1 for interference microscopes having holos:graphic features or for making holograms.

Using polarized light:
This subclass is indented under subclass 370. Subject matter wherein light with a particular polarization characteristic is present.

SEE OR SEARCH THIS CLASS, SUBCLASS:
386 for illuminators for microscopes other than interference microscopes using polarized light.
483 for optics, systems, and elements for polarization of light or using polarized light.

With plural optical axes:
This subclass is indented under subclass 368. Subject matter wherein light from an object may follow any of a plurality of substantially different optical axes through the microscope.
(1) Note. The different optical axes may be partly colinear and may be used either simultaneously or alternately.

SEE OR SEARCH THIS CLASS, SUBCLASS:
363 for a compound lens system with an image recorder.
403 for a periscope with plural optical axes.
419 for a telescope with plural optical axes.

Side-by-side fields:
This subclass is indented under subclass 372. Subject matter wherein at least two of the separate paths provide different images which are adjacent in a common field of view.

Plural oculars:
This subclass is indented under subclass 372. Subject matter wherein at least two of the separate paths terminate in separate eyepieces.

Binocular:
This subclass is indented under subclass 374. Subject matter wherein at least two of the plural oculars are separated at approximately the interocular distance to provide simultaneous viewing by both eyes of one observer.

SEE OR SEARCH THIS CLASS, SUBCLASS:
404 for a binocular periscope.
407 for a binocular telescope.
480 for a binocular viewing device in general.

Stereoscopic:
This subclass is indented under subclass 375. Subject matter wherein at least two of the binocular eyepieces provide stereoscopic viewing.

SEE OR SEARCH THIS CLASS, SUBCLASS:
462 for steroscopic viewing systems.

With single or parallel objectives:
This subclass is indented under subclass 376. Subject matter including one objective for two stereoscopic views or two objectives with parallel optical axes for two stereoscopic views.

For viewing stereo pairs:
This subclass is indented under subclass 377. Subject matter wherein separate objective channels view different object fields, each field being filled by a separate parallax object view for viewing.
(1) Note. The devices of this subclass provide for two separate fields. The stereoscopic property is related to the objects being viewed taken from two slightly different directions of a three-dimensional object. The views usually comprise a pair of transparencies, each transparency being a separate object view.

SEE OR SEARCH THIS CLASS, SUBCLASS:
466 for stereo-viewing devices.

Spacing of optical elements axially adjustable:
This subclass is indented under subclass 368. Subject matter
including means for varying the axial separation of the optical elements, for example, for focusing or varying magnification.
(1) Note. Other subclasses in this class indented under subclass 399, Telescope, and titled "Separation of optical elements axially adjustable" or including the word "focusing" may include subject matter related to subject matter in this subclass (379).

SEE OR SEARCH THIS CLASS, SUBCLASS:
506 for an adjustable extended spacing structure for optical elements.

Variable magnification:
This subclass is indented under subclass 379. Subject matter wherein varying the axial separation varies the size of an in focus terminal image while the object distance remains constant.
(1) Note. Other subclasses in this class indented under subclass 407, Binocular, and titled "Spacing of optical elements axially adjustable" may include subject matter related to variable magnification.

SEE OR SEARCH THIS CLASS, SUBCLASS:
422 for a telescope with variable magnification.
432 for variable magnification in nonmagnifying compound lens systems.
506 for adjustable extended spacing structure for optical elements.
676 for a lens having its equivalent focal length variable continuously between limits.

Imaging elements movable in and out of optical axis:
This subclass is indented under subclass 368. Subject matter wherein an imaging element is selectively positionable in or out of the optical axis to change the image distance or image size.

SEE OR SEARCH THIS CLASS, SUBCLASS:
421 for a telescope with selective magnification.

Entire microscope adjustable along optical axis:
This subclass is indented under subclass 368. Subject matter wherein the microscope translates along the optical axis to vary the distance to an object plane.

SEE OR SEARCH THIS CLASS, SUBCLASS:
392 for devices wherein the stage or slide carrier translates along the optical axis.

SEE OR SEARCH CLASS:
74, Machine Element or Mechanism, 25 for a mechanism converting rotary motion to or from reciprocating or oscillatory motion.

Focus adjustment:
This subclass is indented under subclass 382. Subject matter wherein the adjustment along the optical axis effects the focus of the compound optical system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
410 for binocular telesopes with adjustable focus.
425 for telescopes with focusing.

With rotatable adjustment:
This subclass is indented under subclass 368. Subject matter including means for swinging the microscope about an axis.

Illuminator:
This subclass is indented under subclass 368. Subject matter including (a) structure for illuminating an object being viewed in combination with a microscope or (b) object
illuminating structure designed specifically for use with a microscope.

SEE OR SEARCH THIS CLASS, SUBCLASS:
798 for lenses with viewed object or viewed field illumination.

SEE OR SEARCH CLASS:
362, Illumination, 257 and 317+ for an illuminator with a modifier or a light modifier.

Using polarized light:
This subclass is indented under subclass 385. Subject matter wherein the illuminating structure provides polarized light.

SEE OR SEARCH THIS CLASS, SUBCLASS:
371 for an interference microscope using polarized light.
483 for systems and elements for the polarization of light without modulation.

SEE OR SEARCH CLASS:
362, Illumination, subclass 19 for an illuminator with a polarizer.

With annular lighting structure:
This subclass is indented under subclass 385. Subject mattter including means for providing an annulus of light surrounding a dark central portion for illuminating the object.

With optical switching means:
This subclass is indented under subclass 385. Subject matter including means for changing optical elements in the illuminating beam path to change the type of illumination.
(1) Note. The optical elements may be movable in and out of the illuminating beam path or the illuminating beam may be
deflected to pass through different optical elements.

With illuminating and viewing paths coaxial at the image field:
This subclass is indented under subclass 385. Subject matter wherein the illuminating light is transmitted through a space occupied by the image field.
(1) Note. A partially transmitting beam splitter is commonly used in devices in this subclass (389).

SEE OR SEARCH THIS CLASS, SUBCLASS:
799 for a lens with a coaxial illuminating beam.

With illuminator support:
This subclass is indented under subclass 385. Subject matter including (a) means for maintaining the illuminator in a fixed position or (b) means for limiting the movement of the illuminator.

SEE OR SEARCH CLASS:
362, Illumination, 382 for an illuminator with a support.

Stage or slide carrier:
This subclass is indented under subclass 368. Subject matter including (a) structure for supporting an object to be viewed or tools to be placed in the field of view in combination with a microscope or (b) structure for supporting an object or tools designed specifically for use with a microscope.

SEE OR SEARCH THIS CLASS, SUBCLASS:
801 and 804+, for lenses with a viewed object support.

SEE OR SEARCH CLASS:
248, Supports, for supports generally.

Adjustable along optical axis:
This subclass is indented under subclass 391. Subject matter wherein the stage or slide carrier translates along the optical axis to vary its distance from the microscope.

SEE OR SEARCH THIS CLASS, SUBCLASS:
382 for devices wherein the microscope translates along the optical axis.

SEE OR SEARCH CLASS:
74, Machine Element or Mechanism, 25 for a mechanism converting rotary motion to or from reciprocating or oscillatory motion.
108, Horizontally Supported Planar Surfaces, 144.11 for a vertically adjustable platform.

With plural transverse movements:
This subclass is indented under subclass 391. Subject matter wherein the stage or slide carrier is movable in a plurality of directions perpendicular to the optical axis of the microscope.

SEE OR SEARCH CLASS:
74, Machine Element or Mechanism, subclass 471 for X-Y control devices.
108, Horizontally Supported Planar Surfaces, 137 for a horizontally adjustable platform.

With turntable:
This subclass is indented under subclass 391. Subject matter wherein the stage or slide carrier is rotatable about the optical axis or an axis parallel to the optical axis of the microscope.

With temperature control:
This subclass is indented under subclass 391. Subject matter including means to vary or keep constant the temperature at the location of the stage or slide carrier.

SEE OR SEARCH THIS CLASS, SUBCLASS:
396 for devices including a transparent slide which may include temperature control means.

Transparent slide:
This subclass is indented under subclass 368. Subject matter including (a) a transparent mass, usually a glass plate, for supporting an object to be viewed in combination with a microscope or (b) a transparent mass, usually a glass plate, designed specifically for supporting an object to be viewed by a microscope.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, 244 for sample or specimen holders.

Reference lines or grids:
This subclass is indented under subclass 396. Subject matter including indicia on the transparent slide.

Specimen cavity or chamber:
This subclass is indented under subclass 396. Subject matter including a container for holding, isolating, or limiting the flow of an object.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, subclass 246 for fluid sample containers.

Telescope:
This subclass is indented under subclass 362. Subject matter wherein the compound lens system is designed for viewing distant objects.

With viewed screen:
This subclass is indented under subclass 399. Subject matter including a semi-transparent or opaque structure for displaying one of the series of real images.
(1) Note. The screen may be at an interminate or terminal image plane and may, for example, comprise a ground glass screen, a front projection screen, a fiber optic output face, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:
369 for a microscope with a viewed screen.
443 for a viewing screen.
505 for an extended spacing structure for optical elements including a screen.

SEE OR SEARCH CLASS:
250, Radiant Energy, subclass 213 for circuits having image intensifier or nonvisible to visible imaging vacuum tubes.
313, Electric Lamp and Discharge Devices, subclass 524 for a telescope (or any optical system) combined with an image intensifier.
353, Optics: Image Projectors, subclass 18, 47, 67, 72+, 74+, and 79+ for an image projector and viewing screen in combination.

With image anti-rotation:
This subclass is indented under subclass 399. Subject matter wherein the telescope maintains an erect terminal image as at least part of the telescope is turned to rotate an intermediate image.

SEE OR SEARCH THIS CLASS, SUBCLASS:
554 for an image stabilization system including image anti-rotation.

Periscope:
This subclass is indented under subclass 399. Subject matter wherein the entrance optical axis and the exit optical axis of the telescope are parallel and offset and perpendicular to the main axis of the telescope.

SEE OR SEARCH THIS CLASS, SUBCLASS:
401 for a periscope with image anti-rotation.

With plural optical axes:
This subclass is indented under subclass 402. Subject matter wherein light from an object may follow any of a plurality of substantially different optical axes through the periscope.
(1) Note. The different optical axes may be partly colinear and may be used either simultaneously or alternately.

SEE OR SEARCH THIS CLASS, SUBCLASS:
372 for a microscope with plural optical axes.
419 for a telescope with plural optical axes.

Binocular:
This subclass is indented under subclass 403. Subject matter wherein at least two of the substantially different axes provide separate views to separate eyepieces for binocular viewing.

SEE OR SEARCH THIS CLASS, SUBCLASS:
375 for a binocular microscope.
407 for a binocular telescope.
480 for a binocular viewing device in general that does not use a compound lens system.

With mechanical adjustment:
This subclass is indented under subclass 402. Subject matter wherein all or a portion of the periscope relative to another structure is moved.

SEE OR SEARCH THIS CLASS, SUBCLASS:
429 for a telescope with line of sight adjustment.

Extensible structure:
This subclass is indented under subclass 405. Subject matter wherein the extension or elevation of the periscope is changed, usually by the use of telescoping structures.

Binocular:
This subclass is indented under subclass 399. Subject matter wherein at least two exit optical axes are spaced at approximately the interocular distance to provide simultaneous viewing by both eyes of one observer.
(1) Note. This is the type of device used by fans at a ball game to see distant players.

SEE OR SEARCH THIS CLASS, SUBCLASS:
375 for a binocular microscope.
404 for a binocular periscope.
480 for a binocular viewing device in general that does not use a compound lens system.

Foldable or collapsible:
This subclass is indented under subclass 407. Subject matter wherein the binocular telescope is hinged or provided with telescoping or bellows sections to provide a more compact unit when not in use or prior to assembly.

SEE OR SEARCH THIS CLASS, SUBCLASS:
474 for a collapsible stereoscope.
817 for a lens with a foldable or collapsible support.

Body supported or with handle:
This subclass is indented under subclass 407. Subject matter wherein the binocular telescopes are combined with (a) an elongated structure for providing a handhold or (b) a structure for engaging a portion of the body or apparel for support.

With focusing means:
This subclass is indented under subclass 409. Subject matter wherein the supported binocular telescope includes means for bringing an object at varying distances into focus.
(1) Note. Other subclasses in this class indented under subclass 412 with adjustable interocular distance and titled "Spacing of optical elements axially adjustable" may include subject matter related to focusing.

SEE OR SEARCH THIS CLASS, SUBCLASS:
379 for a microscope with the spacing of optical elements axially adjustable.
425 for a telescope with focusing or relatively sliding barrels.
506 for an adjustable extended spacing structure for optical elements.

With adjustable interocular distance:
This subclass is indented under subclass 409. Subject matter wherein the supported binocular telescopes are connected by means which vary and maintain lateral spacing of the two binocular optical axes.

With adjustable interocular distance:
This subclass is indented under subclass 407. Subject matter wherein the binocular telescopes are connected by means which vary and maintain lateral spacing of the two binocular optical axes.

Oculars swing about central axis:
This subclass is indented under subclass 412. Subject matter wherein the lateral spacing is changed by swinging the binocular telescopes about a common axis.

Spacing of optical elements axially adjustable:
This subclass is indented under subclass 413. Subject matter wherein the axial separation of optical elements, usually lenses, prisms, or mirrors, may be varied, usually for focusing or varying magnification.
(1) Note. Other subclasses in this class indented under subclass 362, Compound lens system, and titled "Separation of elements axially adjustable", "Variable magnification" or including the word "focusing" may include subject matter related to subject matter in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
506 for an adjustable extended spacing structure for optical elements.

Oculars rotate about separate axes:
This subclass is indented under subclass 412. Subject matter wherein the lateral spacing is varied by rotating the binocular telescopes about different axes displaced from their optical axes.

Spacing of optical elements axially adjustable:
This subclass is indented under subclass 415. Subject matter wherein the axial separation of optical elements, usually lenses, prisms, or mirrors, may be varied, usually for focusing or varying magnification.
(1) Note. Other subclasses in this class indented under subclass 362, Compound lens system, and titled "Separation of optical elements axially adjustable", "Variable magnification" or including the word "focusing" may include subject matter related to subject matter in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
506 for an adjustable extended spacing structure for optical elements.

Spacing of optical elements axially adjustable:
This subclass is indented under subclass 412. Subject matter wherein the axial separation of optical elements, usually lenses, prisms, or mirrors, may be varied, usually for focusing or varying magnification.
(1) Note. Other subclasses in this class indented under subclass 362, Compound lens system, and titled "Separation of optical elements axially adjustable", "Variable magnification", or including the word "focusing" may include subject matter related to subject matter in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
506 for an adjustable extended spacing structure for optical elements.

Spacing of optical elements axially adjustable:
This subclass is indented under subclass 407. Subject matter wherein the axial separation of optical elements, usually lenses, prisms, or mirrors, may be varied, usually for focusing or varying magnification.
(1) Note. Other subclasses in this class indented under subclass 362, Compound lens system, and titled "Separation of optical elements axially adjustable", "Variable magnification" or including the word "focusing" may include subject matter related to subject matter in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
506 for an adjustable extended spacing structure for optical elements.

With plural optical axes:
This subclass is indented under subclass 399. Subject matter wherein light from an object may follow any of a plurality of substantially different paths through the telescope.
(1) Note. The different optical axes may be partly colinear and may be used either simultaneously or alternately.

SEE OR SEARCH THIS CLASS, SUBCLASS:
372 for a microscope with plural optical axes.
403 for a periscope with plural optical axes.

Plural magnification in same viewing field:
This subclass is indented under subclass 419. Subject matter wherein telescope images of different magnification are simultaneously viewable in a common field of view.

Selectable magnification:
This subclass is indented under subclass 399. Subject matter wherein the telescope includes means for step variations of the image size while the object distance remains constant.

SEE OR SEARCH THIS CLASS, SUBCLASS:
381 for a microscope with an imaging element movable in and out of the optical axis.

Variable magnification:
This subclass is indented under subclass 399. Subject matter wherein the telescope continuously varies the size of the image while the object distance remains constant.
(1) Note. Other subclasses in this class indented under subclass 407, Binocular, and titled "Separation of optical elements axially adjustable" may include subject matter related to variable magnification.

SEE OR SEARCH THIS CLASS, SUBCLASS:
380 for a microscope with variable magnification.
432 for a compound lens system with variable magnification.
506 for adjustable extended spacing structure for optical elements.
676 for a lens having its equivalent focal length variable continously between limits.

With relay:
This subclass is indented under subclass 399. Subject matter wherein the telescope includes at least one lens system which forms a real image of a real image.

SEE OR SEARCH THIS CLASS, SUBCLASS:
402 for a periscope including a relay.
422 for a variable magnification telescope including a relay.
434 for a compound lens system with a relay.

With reticle:
This subclass is indented under subclass 423. Subject matter wherein a cross-hair or emblem is present at a real image plane of the telescope.

SEE OR SEARCH THIS CLASS, SUBCLASS:
422 for a variable magnification telescope including a relay and a reticle.
427 for focusing or relatively sliding barrels with a reticle.
428 for a telescope with a reticle.
505 for an extended spacing structure for optical elements
with a reticle.

Focusing or relatively sliding barrels:
This subclass is indented under subclass 399. Subject matter wherein the telescope includes (a) a device for forming an in focus image of an object of varying distances or (b) tubes supporting optical elements movable axially into and out of one another.
(1) Note. Other subclasses in this class indented under subclass 362, Compound lens system, and titled "Separation of optical elements axially adjustable" may include subject matter related to subject matter in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
410 for a binocular telescope that is body supported or with a handle and includes focusing means.
506 for an adjustable extended spacing structure for optical elements.

Internal focusing:
This subclass is indented under subclass 425. Subject matter wherein the entrance and exit lenses remain a fixed distance apart while the telescope is focused.

With reticle:
This subclass is indented under subclass 425. Subject matter wherein a cross-hair or emblem is present at a real image plane of the telescope.

SEE OR SEARCH THIS CLASS, SUBCLASS:
422 for a variable magnification telescope including a relay and a reticle.
424 for a telescope with a relay and a reticle.
428 for a telescope with a reticle.
505 for an extended spacing structure for optical elements
with a reticle.

With reticle:
This subclass is indented under subclass 399. Subject matter wherein a cross-hair or emblem is present at a real image plane of the telescope.

SEE OR SEARCH THIS CLASS, SUBCLASS:
422 for a variable magnification telescope including a relay and a reticle.
424 for a telescope with a relay and a reticle.
427 for a telescope with focusing or relatively sliding barrels and with a reticle.
505 for an extended spacing structure for optical elements with a reticle.

With line of sight adjustment:
This subclass is indented under subclass 399. Subject matter wherein the telescope includes adjusting the direction of view and maintaining the adjustment.

SEE OR SEARCH THIS CLASS, SUBCLASS:
401 for a telescope with image anti-rotation.
405 for a periscope with mechanical adjustment.

SEE OR SEARCH CLASS:
248, Supports, 127 for stands in general.

Equatorial mount:
This subclass is indented under subclass 429. Subject matter wherein the telescope includes structure to establish an axis (polar axis) parallel to the earth's rotational axis about which the telescope viewing axis rotates (right ascension) at a selected angle (declination) between the polar axis and the viewing axis.

With prism or U-shaped optical path:
This subclass is indented under subclass 399. Subject matter wherein the telescope includes two right angle deflections in series to reverse the optical path.

SEE OR SEARCH THIS CLASS, SUBCLASS:
413 for adjustable binoculars including a prism or a U-shaped optical path.

Variable magnification:
This subclass is indented under subclass 362. Subject matter wherein the compound lens system continuously varies the size of a terminal image while the object distance remains constant.
(1) Note. Other subclasses in this class indented under subclass 407, Binocular, and titled "Spacing of optical elements axially adjustable" may include subject matter related to variable magnification.

SEE OR SEARCH THIS CLASS, SUBCLASS:
380 for variable magnification in microscopes.
422 for variable magnification in telescopes.

With tilted lens or tilted image plane:
This subclass is indented under subclass 362. Subject matter wherein the compound lens system includes (a) at least one lens whose optical axis is oblique to the optical axis of the system or (b) is designed to produce at least one image plane tilted with respect to the optical axis of the system.

With relay:
This subclass is indented under subclass 362. Subject matter
wherein the compound lens system includes at least one lens system that forms a real image of a real image.

SEE OR SEARCH THIS CLASS, SUBCLASS:
423 for a telescope with a relay.

Repetitious lens structure:
This subclass is indented under subclass 434. Subject matter wherein the compound lens system includes (a) a plurality of identical relays in series or side by side or (b) at least one relay comprised of identical elements or elements symmetrically reversed about a center point.

SCALE OR INDICIA READING:
This subclass is indented under the class definition. Subject matter including optical structure for facilitating the reading of a scale, with or without a pointer or indicator, having spaced lines or other indicia thereon; or for facilitating reading a vernier type indicator where lines from two different scales are matched.
(1) Note. The scale may be on a weighing instrument, slide rule, compass or speed indicator, etc.; and classification is here unless sufficient scale supporting structure is recited to classify with the particular art such as Class 33, Geometrical Instruments; Class 73, Measuring and Testing; Class 177, Weighing Scales; and Class 235, Registers.

SEE OR SEARCH CLASS:
116, Signals and Indicators, 327 for signal pointers and indicating arms.
177, Weighing Scales, subclass 234 for self-positioning scales with magnified indication of spring deformation.
356, Optics: Measuring and Testing, subclass 242.1 for thread counters and similar subject matter where a relationship between the counter and the fabric is recited such as a viewing aperture or support for the counter on the fabric or a fabric support, subclasses 247+ for optical reticles and crosshairs and subclasses 373 and 397 for distance measuring devices which have a scale or optical grid displaced relative to a remote fiducial mark.
362, Illumination, 23 for dial illuminators.

Polarizer:
This subclass is indented under subclass 436. Subject matter including a polarizing element.
(1) Note. A polarizing element causes incident light polarization as defined in the class definition.

SEE OR SEARCH THIS CLASS, SUBCLASS:
485 for specific polarizing elements.

Prism:
This subclass is indented under subclass 436. Subject matter including a prism which may reflect or refract light for better viewing the scale or indicia.
(1) Note. See subclass 831 for the definition of a prism.

SEE OR SEARCH THIS CLASS, SUBCLASS:
831 for specific prism elements.

Mirror:
This subclass is indented under subclass 436. Subject matter including a mirror to reflect light from the scale or indicia to the viewer.
(1) Note. See subclass 838 for the definition of a mirror.

SEE OR SEARCH THIS CLASS, SUBCLASS:
838 for mirrors, per se.

Lens:
This subclass is indented under subclass 436. Subject matter including a lens.
(1) Note. See subclass 642 for the definition of a lens.
(2) Note. The lens is usually employed to magnify the image of the scale markings or indicia.

SEE OR SEARCH THIS CLASS, SUBCLASS:
806 for optical reading devices including line markers.
809 for lenses combined with diverse type art devices in general.

SEE OR SEARCH CLASS:
73, Measuring and Testing, subclass 327 for a reflector or magnifier used for sighting in a liquid level or depth gauge.

Movable or adjustable:
This subclass is indented under subclass 440. Subject matter including means for adjusting or moving the lens with respect to the scale or indicia as for positioning or focusing the lens.

SEE OR SEARCH THIS CLASS, SUBCLASS:
642 for lenses, per se.

Along scale or indicia:
This subclass is indented under subclass 441. Subject matter including means to guide a lens along the reading direction of a linear scale or indicia.
(1) Note. The lens may be movable along a nonlinear (e.g., circular) scale as well as a linear scale and the structure must be included which constricts or guides the movement of the lens along the scale or indicia.
(2) Note. An actuator, per se, is not classified in this subclass.

PROJECTION SCREEN:
This subclass is indented under the class definition. Subject matter including a sheet or other extending surface or area which is especially adapted to render an image of an object which is projected thereon visible to an observer, usually by diffusing the projected light.
(1) Note. This subclass and those indented thereunder in this class (359) include screens where the size, shape, or refractive index of embedded particles is claimed or screens with elements having geometric curves, with relative refractive indices or parts with claimed patterns, with wave plates, acoustical characteristics or other optical criterion. Such criterion must be more than mere "light diffusing particles" or a "light diffusing surface" to classify a patent in Class 359 as opposed to Class 139 or Class 428. See Class 427, appropriate subclasses for methods of making screens by coating.
(2) Note. The screen may be merely tracing paper or a canvas as in indented subclass 447.

SEE OR SEARCH THIS CLASS, SUBCLASS:
350 for a viewing screen having infrared or ultraviolet characteristics.
900 for miscellaneous methods of making screens not classified in Class 427, Coating Processes, or Class 156, Adhesive Bonding and Miscellaneous Chemical Manufacture, etc.

SEE OR SEARCH CLASS:
139, Textiles: Weaving, 383 for light diffusing woven screens.
160, Flexible or Portable Closure, Partition, or Panel, especially 19 and 371+ for framed screens without optical details other than merely "translucent" or something similar.
248, Supports, especially 158 for screen supports.
264, Plastic and Nonmetallic Article Shaping or Treating: Processes, 1.1 for processes directed to forming optical articles capable of producing an optical effect other than mere transparency or planar reflection.
312, Supports: Cabinet Structure, 21 for screens supported in a cabinet.
352, Optics: Motion Pictures, subclass 61 for a motion picture projector combined with a screen.
353, Optics: Image Projectors, subclass 18, 47, 67, 72+, 74+, and 79+ for cabinet which encloses projector and one
side of screen or structurally related projector and screen.
427, Coating Processes, 162 for coating processes, per se, wherein the product is an optical element.
428, Stock Material or Miscellaneous Articles, especially 143 for embedded light diffusing particles or for light diffusing stock material in the form of a single or plural layer web or stock material which may be useful for projection purposes.

With sound producer:
This subclass is indented under subclass 443. Subject matter including a loudspeaker or other sound producing means combined with the screen.

SEE OR SEARCH CLASS:
352, Optics: Motion Pictures, subclass 36 for motion picture devices combined with screens and sound producers.
353, Optics: Image Projectors, subclass 18 for an image projector in combination with a sound producer.
381, Electrical Audio Signal Processing Systems and Devices, 150 for electrical loudspeakers, per se.

Acoustical:
This subclass is indented under subclass 443. Subject matter wherein the screen is especially adapted to transmit or damp sound waves.

SEE OR SEARCH THIS CLASS, SUBCLASS:
444 for acoustical screens combined with means to produce sound.

SEE OR SEARCH CLASS:
181, Acoustics, 175 for mufflers and sound filters.

Moving during projection:
This subclass is indented under subclass 443. Subject matter including means to rotate or oscillate the screen, usually for the purpose of improving the image seen by viewers or for imparting a three dimensional effect.

SEE OR SEARCH THIS CLASS, SUBCLASS:
520 for vibrating, oscillating, or rotating signal reflectors.

Tracing (e.g., camera lucida, etc.):
This subclass is indented under subclass 443. Subject matter wherein the screen upon which an image is formed is adapted to have an outline of the image traced or sketched thereon.
(1) Note. The instrument, commonly referred to as a camera lucida, usually includes a prism or mirrors and sometimes a lens to cause a virtual image of an object to appear as if projected upon a plane surface so that an outline may be traced.

SEE OR SEARCH THIS CLASS, SUBCLASS:
369 and 400, for a compound lens system combined with a viewing screen.
448 for a lens combined with a viewing screen.
449 for a reflector combined with a viewing screen.

SEE OR SEARCH CLASS:
353, Optics: Image Projectors, subclass 44 and 45 for an image projector having a concentrated source of light to project an image for the purpose of tracing it.

With lens (e.g., camera obscura, etc.):
This subclass is indented under subclass 443. Subject matter including a lens combined with the screen, the screen usually being positioned in the second principle focal plane of the lens.
(1) Note. The device, commonly known as a camera obscura, usually has a darkened chamber with a lens at the entrance thereof to permit light from external objects to enter and to form an image of the objects on a screen in the chamber.
(2) Note. The combinations classified here are often constructed to function normally only when the light rays approaching the entrant lens from the object are substantially parallel, under which conditions the image produced by the device is always greatly reduced relative to the size of the object. The lens and screen combinations classified in Class 353, Optics: Image Projectors, differ from those classified here in that they are constructed to operate normally only when the light rays approaching the entrant lens from the object are of the widely diverging type, that is, when the object is near the first principal focal plane of the entrant lens, under which conditions the image produced by the device is enlarged relative to the size of the object, a condition that usually necessitates the use of intense artifical object illumination to provide an adequately illuminated image. Moreover, the lens and screen combinations of Class 353, Optics: Image Projectors, always have their object and screen in the conjugate focal planes of the projection lens employed with the screen spaced more distant from the lens than the object, while the lens and screen combinations of this subclass 448 have their object and screen substantially at infinity and at the principal focal plane of the lens respectively.

SEE OR SEARCH THIS CLASS, SUBCLASS:
369 and 400, for a compound lens system combined with a viewing screen.

SEE OR SEARCH CLASS:
353, Optics: Image Projectors, subclass 18, 47, 67, 72+, 74+, and 79+ for an image projector having a light source or means to concentrate solar light and including a lens and screen combination. See (2) Note above.

With reflector or additional screen:
This subclass is indented under subclass 443. Subject matter including another screen or a reflector which usually is between the first screen and a projector.

SEE OR SEARCH THIS CLASS, SUBCLASS:
447 for camera lucidas which include reflectors.

SEE OR SEARCH CLASS:
353, Optics: Image Projectors, subclass 67, 73, 77, and 78 for an image projector having a screen and a reflector.

Border, mask, shade, or curtain:
This subclass is indented under subclass 443. Subject matter including means connected to the screen to shield or shade the screen or to modify the contrast between the screen and the surrounding area.
(1) Note. For the purpose of this subclass, drapes, hoods, and covers are considered to be curtains.

Curved:
This subclass is indented under subclass 443. Subject matter wherein the surface of the screen is articulated rather than flat.
(1) Note. In this subclass the overall shape or surface of the screen is curved but subclasses 455 and 459 have curved individual elements but the overall surface of the screen is generally flat.

Embedded particles:
This subclass is indented under subclass 443. Subject matter including a mass or sheet of material (e.g., resin, etc.) with particles partially or fully embedded therein to affect the light transmission or reflection characteristics of the screen, the particles having characteristics such as a particular geometric shape, size, or refractive index.
(1) Note. The screens in Class 428, Stock Material or Miscellaneous Articles, subclasses 143+ may include particles claimed as light diffusing or as causing translucency. However, if the particles are claimed as having certain refractive index, size or shape, or an index or size relative to the remainder of the screen material, the patent is classified here in subclass 452. Further, if a geometric configuration is formed by the particles in the screen the patent is also classified here in subclass 452.

SEE OR SEARCH CLASS:
427, Coating Processes, 162 for coating processes, per se, wherein the product is an optical element.
428, Stock Material or Miscellaneous Articles, 143 for a stock material product containing embedded particles which
diffuse light, and see (1) Note above.

Rear projection screen:
This subclass is indented under subclass 452. Subject matter wherein an image is projected on one side of a screen and viewed from the opposite side.

Unitary sheet comprising plural refracting areas:
This subclass is indented under subclass 443. Subject matter wherein a plurality of refracting elements are each part of a unitary plate or mass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
455 for a lenticular screen.
542 for signal reflectors with plural refracting elements formed as a unitary mass.

Lenticular:
This subclass is indented under subclass 454. Subject matter wherein at least some of the plurality of refracting elements have spherical or cylindrical curvature.

SEE OR SEARCH THIS CLASS, SUBCLASS:
542 for signal reflectors with plural refracting elements formed as a unitary mass.
619 for surfaces composed of lenticular elements.

Rear projection screen:
This subclass is indented under subclass 455. Subject matter wherein an image is projected on one side of a screen and viewed from the opposite side.

With Fresnel lens:
This subclass is indented under subclass 456. Subject matter wherein the lenticulated rear projection screen includes a Fresnel lens or a lens resembling a plano-convex or plano-concave lens that is cut into narrow rings and flattened out.
(1) Note. See subclass 742 for the definition of Fresnel type lens.

Stereoscopic imaging or three dimensional imaging:
This subclass is indented under subclass 455. Subject matter wherein a lenticulated refractive screen is placed between a picture and a viewer eye to provide an illusion of relief or an illusory three dimension picture of a single perspective.

SEE OR SEARCH THIS CLASS, SUBCLASS:
462 for stereoscopic device that may include a nominal recitation of a projection screen.
478 for relief illusion.

SEE OR SEARCH CLASS:
352, Optics: Motion Pictures, 57 for stereoscopic camera or projectors and subclasses 85+ for special effects, particularly subclass 86 for devices creating an illusion of three dimensional viewing without employing separate left and right images.

Unitary sheet comprising plural reflecting areas:
This subclass is indented under subclass 443. Subject matter wherein a plurality of discrete reflecting elements are part of a unitary plate or sheet, the reflecting elements redirecting the impinging light in different directions.
(1) Note. The discrete elements are usually angularly related or curved.

SEE OR SEARCH THIS CLASS, SUBCLASS:
530 for a unitary sheet comprising a plurality of cube
corner or triple reflectors.
546 for discrete reflecting elements formed as a unitary mass.
619 for surfaces composed of lenticular elements.

Rear projection screen:
This subclass is indented under subclass 443. Subject matter wherein an image is projected on one side of a screen and viewed from the opposite side.

Roll up screen:
This subclass is indented under subclass 443. Subject matter wherein the screen is flexible and can be wound around a roller for easy storage or for portability.

STEREOSCOPIC:
This subclass is indented under the class definition. Subject matter comprising (1) a separate optical system for each eye of one person, which are looking at a common object, for producing separate visual records containing information from the two different points of view relative to that object, or (2) the stereoscopic record itself, or (3) the devices for viewing such records.
(1) Note. This subclass takes optical systems of stereo projectors and cameras which are not sufficient to constitute a complete projector or camera.

SEE OR SEARCH THIS CLASS, SUBCLASS:
478 for devices giving an illusion of relief but where information is obtained only from a single point of view.

SEE OR SEARCH CLASS:
33, Geometrical Instruments, subclass 1 for measuring stereoscopes and subclass 20.4 for plotting stereoscopes combined with a stylus.
40, Card, Picture, or Sign Exhibiting, subclass 1 for
exhibitors in general, and subclasses 361+ for nonstereo transparent film viewers.
348, Television, 42 for stereoscopic television systems.
352, Optics: Motion Pictures, 57 for stereoscopic motion picture cameras.
353, Optics: Image Projectors, 7 for attachments which convert a conventional projector to a stereoscopic image projector.
356, Optics: Measuring and Testing, 12 for base line type range or height finders which include stereoscopic viewers and subclass 390 for mensuration or configuration comparison devices which may involve stereo-viewers.
378, X-Ray or Gamma Ray Systems or Devices, 41 for a stereoscopic X-ray or gamma ray system.
396, Photography, 324 for stereoscopic camera.

Having record with lenticular surface:
This subclass is indented under subclass 462. Subject matter comprising a record with a plurality of reflecting or transmitting elements, each having a curved or figured surface.

SEE OR SEARCH THIS CLASS, SUBCLASS:
455 for lenticular projection screens.
619 for surfaces composed of lenticular elements.
642 for lenses generally.
727 for lenses having concave and/or convex reflecting surfaces with coatings.

With right and left channel discriminator (e.g., polarized or colored light):
This subclass is indented under subclass 462. Subject matter associated with stereo systems wherein by appropriate viewing devices (e.g., colored or polarizing spectacles), light rays representing the right and left stereoscopic channels and having different optical properties (e.g., color, direction of polarization), in accordance with the channel they
represent, will affect only the eye appropriate to a given channel.
(1) Note. This subclass includes for example, (1) apparatus for forming superimposed images from light rays having different optical properties, (2) the record containing right and left stereo images characterized by having different optical properties, or (3) the viewing devices for discriminating between the light rays from the right and left images.

Using polarized light:
This subclass is indented under subclass 464. Subject matter wherein the particles of the light vibrate perpendicular to the direction of travel and these vibrations are either in straight lines, circles, or ellipses.

SEE OR SEARCH THIS CLASS, SUBCLASS:
483 for optics, systems and elements for polarization of light or using polarized light.

Stereo-viewers:
This subclass is indented under subclass 462. Subject matter comprising either (1) viewing devices which are used to aid the observer in fusing adjacently mounted right and left stereoscopic pictures or (2) the adjacently mounted right and left stereoscopic pictures themselves.

SEE OR SEARCH THIS CLASS, SUBCLASS:
804 for nonstereo viewers with a significant lens system.

View changers:
This subclass is indented under subclass 466. Subject matter including means to facilitate changing from one stereoscopic slide or picture to another.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, 446 for changeable exhibitors in general.
353, Optics: Image Projectors, subclass 92 and 103+ for a slide changer for an image projector.

Picture moves linearly past viewing aperture:
This subclass is indented under subclass 467. Subject matter wherein the slide or picture being viewed moves linearly past the viewing aperture, i.e., each point on the picture generates a straight line as it passes the aperture.

Using film-strips:
This subclass is indented under subclass 468. Subject matter wherein a carrier is formed as a tape or strip with individual elements of a motion picture sequence uniformly spaced along the strip.
(1) Note. Film strips may include moving film, film-roll band, ribbon of film, film tape, or film spools.

SEE OR SEARCH CLASS:
352, Optics: Motion Pictures, subclass 37 for strip type films with a sound record, subclass 56 for methods of working or making a film strip, subclass 59 for stereoscopic apparatus involving plural film strips, subclasses 166+ for drive mechanisms for film strips, and subclasses 232+ for motion picture carriers.
353, Optics: Image Projectors, subclass 120 for picture carriers for still projectors.

Compensates for camera position (e.g., plotting or mapping type):
This subclass is indented under subclass 466. Subject matter wherein compensation is made for the orientation or position of the recording device or devices which produced the stereo pictures.
(1) Note. This subject matter generally involves stereoscopes for plotting, mapping, or measuring where the raw data must be adjusted to compensate for such things as parallax, different image size, skew, or tilt, etc., caused
by a particular camera orientation.

SEE OR SEARCH CLASS:
33, Geometrical Instruments, subclass 1 for similar subject matter combined with measuring means and subclass 20.4 for similar subject matter combined with scribing means.
250, Radiant Energy, 200 for similar devices employing photocells.
353, Optics: Image Projectors, subclass 6 for an image projector for stereoscopic mapping or for rectifying an aerial photograph.
356, Optics: Measuring and Testing, subclass 2 for contour plotting devices which may involve stereo-viewers.

Reflected line of sight:
This subclass is indented under subclass 466. Subject matter including means for reflecting the line of sight of at least one eye of the observer.

Pictures offset, transposed, or have respective right or left sides adjacent:
This subclass is indented under subclass 471. Subject matter wherein (1) the pictures viewed are vertically offset (i.e., the tops and bottoms are not in line), (2) the picture to be viewed by the right eye is on the left side of the picture to be viewed by the left eye, or (3) the respective right or left sides of the stereo pictures are adjacent.

Ocular spacing or angle between ocular axes adjustable:
This subclass is indented under subclass 466. Subject matter comprising means for adjusting the spacing of the stereoscope oculars or means for adjusting the angular relationship of their optical axes.

SEE OR SEARCH THIS CLASS, SUBCLASS:
412 for binocular lenses having adjustable interocular spacing.

Collapsible:
This subclass is indented under subclass 466. Subject matter wherein the stereoscope after use can be folded, collapsed, or dismantled to form a more compact package or wherein the stereoscope, prior to use, is folded, collapsed, or dismantled.

SEE OR SEARCH THIS CLASS, SUBCLASS:
817 for lenses with foldable or collapsible supports.

Having Illumination:
This subclass is indented under subclass 466. Subject matter including means to illuminate or improve the illumination of the stereo picture.

SEE OR SEARCH THIS CLASS, SUBCLASS:
798 for illuminating a viewer including a significant lens system.

Ocular to picture distance adjustable:
This subclass is indented under subclass 466. Subject matter including adjustment of the distance between the stereoscopic eyepieces and the viewed picture.

Supporting, mounting, enclosing, or light shielding structure:
This subclass is indented under subclass 466. Subject matter comprising supporting, mounting, enclosing or light shielding structure for stereo viewer or its components.
(1) Note. Examples of this subclass are stereoscopic hoods, cases or handles.

SEE OR SEARCH THIS CLASS, SUBCLASS:
407 for compound lens binocular with supports or handles.
811 for lenses with supports.

RELIEF ILLUSION:
This subclass is indented under the class definition. Subject matter for giving a depth or relief effect comprising a visual record which contains information of the object viewed obtained from only one point of view.

SEE OR SEARCH THIS CLASS, SUBCLASS:
462 for stereoscopic devices where the visual record contains information obtained from two different points of view.

SEE OR SEARCH CLASS:
348, Television, subclass 44 for pseudo stereoscopic television.
352, Optics: Motion Pictures, subclass 86 for a motion picture device for depth illusion.

Reflected line of sight:
This subclass is indented under subclass 478. Subject matter wherein the line of sight of at least one eye of the observer is reflected.

BINOCULAR DEVICES:
This subclass is indented under the class definition. Subject matter comprising one separate optical element, aperture or tube for each eye of the user or comprising a single optical element used alternately by each eye.

SEE OR SEARCH THIS CLASS, SUBCLASS:
404 for telescopic binocular having plural optical axes.
407 for binocular type compound lens system.
466 for stereoscopic viewing devices.
618 for systems including a single optical channel which merges to or from a plural optical channel, the plural channel lacking the binocular use.

Binocular loupe type:
This subclass is indented under subclass 480. Subject matter including a support shaped to position one or more lenses before each eye so that the lenses move with the head of the user.
(1) Note. The support may be adapted to be attached directly to either the head, e.g., a head band, or spectacle frames.

SEE OR SEARCH THIS CLASS, SUBCLASS:
407 for binocular type compound lens systems.
815 for such structure which is body or apparel carried.
816 for monocular loupes.

SEE OR SEARCH CLASS:
2, Apparel, 426 for goggles.
351, Optics: Eye Examining, Vision Testing and Correcting, 41 for spectacles and eyeglasses. See Lines With Other Classes and Within This Class, Lenses, in the 351 Class Definition for the distinction between the vision correcting structure of Class 351 and the magnifying structure of Class 359.

Reflected line of sight:
This subclass is indented under subclass 480. Subject matter wherein the line of sight of at least one eye of the observer is reflected.

POLARIZATION WITHOUT MODULATION:
This subclass is indented under the class definition.
Subject matter wherein the polarization of an incoming light beam is modified in a time invariant fashion as a result of passing through some optical device.
(1) Note. Where both a polarizing device and a composition are claimed, the patent is classified here and cross-referenced to Class 252, subclass 585.
(2) Note. Where a method of making the polarizing device is claimed as well as the polarizing device, the patent is classified here and cross-referenced to any other class providing for the method.
(3) Note. The nominal recitation of a polarizing area in the form of a design, image, etc., is sufficient to include this subject matter in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
122 for optical multiplex communications, using polarization.
246 for electro-optic modulation of polarized light.
281 for magneto-optic modulation of polarized light.
301 for light wave directional control of polarized light.
371 and 386, for compound lens systems combined with polarizers.
437 for polarizers used in a scale or indicia reading.
465 for polarizers used in stereoscopic systems.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, particularly subclass 548 for illuminated signs utilizing polarizers.
250, Radiant Energy, subclass 225 for a light polarizer and a photocell and subclasses 505.1+ for invisible radiation control devices exclusive of infrared and ultraviolet devices which may include polarization devices.
252, Compositions, subclass 585 for chemical compositions which produce polarized light.
313, Electric Lamp and Discharge Devices, subclass 112 for electric lamps and electronic tubes combined with a polarizer.
343, Communications: Radio Wave Antennas, subclass 756 for antennas with a polarization converter and subclasses 909+ for radio wave polarizations, per se.
349, Liquid Crystal Cells, Elements and Systems, subclass 194
for liquid crystal polarizer.
351, Optics: Eye Examining, Vision Testing and Correcting, subclass 49, 215, and 232 for light-polarizing devices used in eye examining vision testing and correcting means.
353, Optics: Image Projectors, subclass 20 for polarizers used with image projectors.
356, Optics: Measuring and Testing, 30 for gem or crystal examining using polarized light; subclass 326 for spectrometers which utilize polarized light; and subclasses 364+ for polarized light examination devices generally.
365, Static Information Storage and Retrieval, subclass 121 for polarization techniques used in the storage and retrieval of information.
472, Amusement Devices, 57 for a theatrical stage device which may use a polarizer.

Time invariant electric, magnetic or electromagnetic field responsive (e.g., electro-optical, magneto-optical):
This subclass is indented under subclass 483. Subject matter wherein an electrical, magnetic, or electromagnetic field, which is unchanging in time, is applied to the device producing the polarization.
(1) Note. This would include optical isolators and circulators.

SEE OR SEARCH CLASS:
360, Dynamic Magnetic Information Storage or Retrieval, subclass 114 for magneto-optical storage systems.
365, Static Information Storage and Retrieval, subclass 122 for information masking using magneto-optical polarization.

Light polarization without any external input:
This subclass is indented under subclass 483. Subject matter wherein an optical device causes optical energy to vibrate in accordance with a regular pattern that differs from the input without the application of any supplemental energy.

SEE OR SEARCH CLASS:
346, Recorders, 107.1 for photos:graphic recorder systems where a phenomenal record is made of an output signal.
347, Incremental Printing of Symbolic Information, 224 for apparatus or processes for marking record receiver using radiation energy (e.g., light or beam), subclasses 129+ for electrostatic marking apparatus or processes including photo scanning device.
356, Optics: Measuring and Testing, subclass 368 for polarimeters which include electro-optical light rotation.

By grid or dipoles:
This subclass is indented under subclass 485. Subject matter wherein electrical conductors in the form of a grid (i.e., each grid opening forms a half wavelength of the applied light) or half wavelength dipoles embedded in the medium produce polarization of the applied light.

By reflection or refraction (e.g., Brewster angle):
This subclass is indented under subclass 485. Subject matter wherein a light beam is polarized as a result of either (1) striking a surface and returning into the originating medium or (2) redirection as it passes through media of differing optical densities.

SEE OR SEARCH THIS CLASS, SUBCLASS:
486 for dipole and grid polarizers.

With particular medium:
This subclass is indented under subclass 487. Subject matter wherein details of the reflecting or refracting medium are recited (e.g., physical composition, structure, specific indexes of refraction, or thickness of layers).
(1) Note. Physical shape (other than layered mediums) or arrangement of elements or mediums is not considered a particular medium for this subclass.

SEE OR SEARCH CLASS:
252, Compositions, subclass 585 for chemical compositions, per se, which produce polarized light.

Polarization (direction or magnitude) varies over surface of the medium (e.g., vectograph):
This subclass is indented under subclass 485. Subject matter comprising a surface which transmits or reflects light and whose ability to polarize light is not uniform across the surface.
(1) Note. This variation in polarizing ability may be continuous or discontinuous and may form any type of pattern. For example, the different areas of a surface may form an image or design as in a "vectograph".

By dichroic medium:
This subclass is indented under subclass 485. Subject matter including an optical element which effects the degree of polarization dependent upon the relative absorption therein of the two components or vectors of light.
(1) Note. A dichroic element will transmit light of one color and reflect light of the complementary color with little light being absorbed. These elements are composed of superimposed strata of dielectric material, which are classified in subclass 580.
(2) Note. Included here are elements where the medium comprises a lamination or a coating on a supporting structure and where the supporting structure is significant or the means to form the lamination or coating is significant.

SEE OR SEARCH CLASS:
156, Adhesive Bonding and Miscellaneous Chemical Manufacture, appropriate subclasses for processes of adhesively bonding laminae.
427, Coating Processes, 162 for coating processes, per se, where the product is an optical element.

Stain or dye:
This subclass is indented under subclass 490. Subject matter wherein a coloring agent is absorbed by the polarization medium to affect the polarization of the applied light beam.

Oriented particles:
This subclass is indented under subclass 490. Subject matter wherein the polarization of the applied light is dependent upon the spatial positioning of microscopic particles embedded in the dichroic medium.

SEE OR SEARCH THIS CLASS, SUBCLASS:
486 for embedded dipoles.
490 for polarization caused by the molecular orientation of the matrix material or of a reaction product.
491 for stain or dye molecules acting as oriented particles.

Glare prevention by discriminating against polarized light:
This subclass is indented under subclass 485. Subject matter wherein unwanted glare-producing light, having a particular polarization, is eliminated by a polarizing structure.

SEE OR SEARCH THIS CLASS, SUBCLASS:
501 for two superimposed relatively adjustable polarizers mounted as a unit and used to reduce or control light intensity.
601 for glare reduction not utilizing a polarizer.

By birefringent element:
This subclass is indented under subclass 485. Subject matter including an element having the property of dividing a ray or beam of energy into two polarized rays or beams (known as the ordinary and extraordinary rays), the directions of polarization being at right angles to each other.
(1) Note. A birefringent material which has been treated with a dichroic dye to absorb the ordinary or extraordinary
ray is no longer considered to be birefringent within the meaning of this definition. A birefringent element in the form of a Nicol prism where the unwanted ray is deflected is classified here.

For beam deflection or splitting:
This subclass is indented under subclass 494. Subject matter wherein the entire beam or a portion of the beam is caused to change direction for positioning purpose or wherein the beam is split into two or more portions.

SEE OR SEARCH THIS CLASS, SUBCLASS:
301 for polarized beam directional modulation.
487 for beam deflection and splitting using nonbirefringent medium.
496 for prism structures which could be used for beam splitting.

Prisms:
This subclass is indented under subclass 494. Subject matter wherein the birefringent element is formed into a structure bound in part by two plane faces that are not parallel and combinations of the structure.

SEE OR SEARCH THIS CLASS, SUBCLASS:
831 for prisms, per se.

Using plural elements:
This subclass is indented under subclass 494. Subject matter wherein beam polarization is achieved by multiple birefringent elements.

SEE OR SEARCH THIS CLASS, SUBCLASS:
250 for plural mediums in electro-optic polarized light modulation.
301 for plural mediums used to deflect the beam where at
least one of the mediums is field responsive.
371 and 386, for microscopes using polarized light which may utilize birefringent elements.
455 for lenticular projection screens with birefringent elements
496 and 497+, for prism structures made up of plural elements and for plural element polarization.

Frequency filter or interference effects:
This subclass is indented under subclass 497. Subject matter wherein plural elements act to pass a particular frequency or band of frequencies, or wherein interference effects are used to produce effects such as color or an interference pattern.

SEE OR SEARCH THIS CLASS, SUBCLASS:
370 for interference microscopes which may utilize birefringent elements.
490 for color effects using dichroic medium.
634 for wavelength selective beam splitting systems.
885 for an absorption filter.

Using compensation techniques:
This subclass is indented under subclass 497. Subject matter wherein at least one of the elements corrects for unwanted effects, such as those due to temperature.

SEE OR SEARCH THIS CLASS, SUBCLASS:
249 for compensating systems in a polarized light electro-optic modulator.

With particular material or mounting structure:
This subclass is indented under subclass 494. Subject matter wherein details of the birefringent material, such as the type, size, shape, crystal cut, or treatment thereof or
detailed structures for mounting the material are recited.

SEE OR SEARCH THIS CLASS, SUBCLASS:
496 for polarization by a prism.

By relatively adjustable superimposed or in series polarizers:
This subclass is indented under subclass 485. Subject matter wherein the polarizers are positioned one on top of another or arranged in a row and their positions are adjustable.

SEE OR SEARCH THIS CLASS, SUBCLASS:
500 for mounting structure of superimposed birefringent elements.

With color filter:
This subclass is indented under subclass 485. Subject matter where a polarizing structure is combined with structure to selectively absorb or transmit specific light wavelengths.

SEE OR SEARCH THIS CLASS, SUBCLASS:
490 for similar subject matter where the color is produced by a dichroic medium. (See (1) Note under subclass 490 for definition of dichroic.)
498 for similar subject matter where the only color produced is a result of interference between the ordinary and extraordinary light rays.

EXTENDED SPACING STRUCTURE FOR OPTICAL ELEMENTS:
This subclass is indented under the class definition. Subject matter including (a) means for maintaining different types of optical elements significantly separated in a fixed or adjustable relationship along the optical axis or (b) means for maintaining lenses significantly separated as in a Galilean telescope or door peep.

SEE OR SEARCH THIS CLASS, SUBCLASS:
744 for afocal lenses (e.g., Galilean telescopes).
894 for optical apertures or tubes or transparent closures.
896 for miscellaneous optical devices.

Wide angle (e.g., door peep):
This subclass is indented under subclass 503. Subject matter wherein an objective element is designed to give a wide field of view, usually at least 120 degrees.

SEE OR SEARCH THIS CLASS, SUBCLASS:
744 for afocal lenses (e.g., Galilean telescopes).
819 for lens mounts.

With screen or reticle in real image plane:
This subclass is indented under subclass 503. Subject matter including a real image display structure or a cross-hair or emblem at a real image plane.

SEE OR SEARCH THIS CLASS, SUBCLASS:
369 for a microscope with a screen.
400 for a telescope with a screen.
422 for a variable magnification telescope including a relay and a reticle.
424 for a telescope with a relay and reticle.
427 for a telescope with focusing or relatively sliding barrels and a reticle.
428 for a telescope with reticle.

Extension of tubular element adjustable:
This subclass is indented under subclass 503. Subject matter including a sliding structure, a bellows, or a telescoping structure for adjusting an optical barrel along the optical
axis relative to another structure.
(1) Note. Other subclasses in this class indented under subclass 362, Compound lens system and titled "Separation of optical elements axially adjustable", "Variable magnification" or including the word "focusing" may include subject matter related to subject matter in this subclass.

PROTECTION FROM MOISTURE OR FOREIGN PARTICLE:
This subclass is indented under the class definition. Subject matter including structure to stop moisture or foreign matter from coming into contact with optical elements or means to remove moisture or foreign matter from optical elements.
(1) Note. Storage or container, per se, for an optical element is classified in Class 206, Special Receptacle or Package, particularly subclasses 5+ for eyeglasses or spectacles and subclasses 316.1+ for other optical or photos:graphic devices or elements.

SEE OR SEARCH CLASS:
15, Brushing, Scrubbing, and General Cleaning, 300.1 for clean-ing machines involving air blast or suction.
134, Cleaing and Liquid Contact With Sol-ids, appropriate subclasses.
427, Coating Processes, 162 for an optical element produced with a coating process.

Optical element rotates:
This subclass is indented under subclass 507. Subject matter where an optical element or a shield therefor is rotated or otherwise moved to throw off moisture or other foreign matter, usually by centrifugal force.
(1) Note. The optical element may be rotated by any motor including one operated by air passing over vanes as in an air operated turbine.

Fluid directed across optical element:
This subclass is indented under subclass 507. Subject matter with structure to direct a fluid across an optical element to blow or wash moisture, or other foreign matter off or to pull such matter off by suction created by the moving fluid.

SEE OR SEARCH THIS CLASS, SUBCLASS:
508 for apparatus where fluid is directed to vanes, as in a turbine, which rotates the optical element or a shield therefor, such as a transparent disc in fron of an objective lens.

SEE OR SEARCH CLASS:
15, Brushing, Scrubbing, and General Cleaning, 300.1 for cleaning machine involving air blast or suction.

Microscope drape:
This subclass is indented under subclass 507. Subject matter including a thin flexible structure loosely encircling a microscope to isolate the microscope from its surroundings.

SEE OR SEARCH THIS CLASS, SUBCLASS:
368 for microscope, per se.

SEE OR SEARCH CLASS:
206, Special Receptacle or Package, subclass 305 and 316.1+ for a special container for an optical instrument.

Cap or cover:
This subclass is indented under subclass 507. Subject matter wherein a usually flanged or flat member covers the end of a barrel of an optical device in order to protect an unused lens, located within a barrel, from dust or from damage by impact with foreign objects.

SEE OR SEARCH THIS CLASS, SUBCLASS:
611 for a shade to deflect unwanted light from a lens.

SEE OR SEARCH CLASS:
15, Brushing, Scrubbing, and General Cleaning, subclass 247 for a cover or cover holder.
439, Electrical Connectors, appropriate subclasses for movable or removable nonuse covering means.

Humidity or temperature control:
This subclass is indented under subclass 507. Subject matter with means for maintaining a desired humidity level or temperature or for increasing or decreasing the humidity level or temperature from its ambient value.

SEE OR SEARCH THIS CLASS, SUBCLASS:
395 for a stage or slide carrier with temperature control.

SEE OR SEARCH CLASS:
34, Drying and Gas or Vapor Contact With Solids, appropriate subclasses.
219, Electric Heating, subclass 219 for an electrically heated mirror.

Sealing:
This subclass is indented under subclass 507. Subject matter with means to seal the optical elements from the atmosphere so that dust or moisture, etc., does not fall on them.

Mirror, prism or signal reflector:
This subclass is indented under subclass 513. Subject matter wherein an element being sealed includes a mirror, prism, or signal reflecting structure.

SIGNAL REFLECTOR:
This subclass is indented under the class definition. Subject matter wherein elements may be specular or diffusing to reflect a light to an observer for signalling purposes.
(1) Note. The presence of a reflector usually is the desired information com-unicated to an observer, i.e., any light, as from an observer's automobile headlights, reflected from the reflector makes the presence of the reflector, and thus danger or need for caution, known to the observer; however, in indented subclass 527, below, some of the reflectors reflect light from a traffic signal light to an observer or reflect light from a source to an observer merely to determine if the source is operating.
(2) Note. The structure of signs with the nominal recitation of a signal reflector are classified in Class 40. In particular an "indicia" design or the conveyance of specific information would be classifiable in Class 40.
(3) Note. Most of the patents in these subclasses relate to highway traffic in the form of indicating the presence of an approaching curve, vehicle, or pedestrian on a roadway.
(5) Note. Since Class 359 is considered superior to Class 116 (See Lines With Other Classes and Within This Class), the use of a signal reflector as a signal source or indicator will be clasified in Class 359, unless the details of the signals and indicators are specified.
(6) Note. Track reflectors having utility with railroads are classified in Class 246.
(7) Note. A nominal recitation, i.e., no optical limitations, of a signal reflector combined with the specifics of its support is classified in Class 248.
(8) Note. The patents of this and indented subclasses are to use the signal reflector to attract attention as opposed to being the source of illumination of Class 362.
(9) Note. A lens, as in a plastic tail light of an automobile used to identify an automobile's presence to a following automobile, is classified in Signal Reflectors (subclasses 515+), rather than Lens (subclasses 642+).
(10) Note. A mirror, located along the side of the road to cause a light flash for identification of the edge of the road as an automobile approaches, is classified in Signal Reflectors (subclasses 515+), rather than Mirror, (subclasses 838+) since a nominal recitation of a mirror claimed with other structure is classified with the other structure.
(11) Note. The combination of an article of clothing and a signal reflector is classified in this subclass since the combination only is classified in Class 2, if not otherwise classifiable.
(12) Note. The combination of an animal collar (i.e., nominal recitation of a collar or harness) together with a signal reflector is classified with the signal reflector of this and indented sub-classes, while a reflector claimed in
combination with more than a nominal collar is classified in Class 119, subclass 858.

SEE OR SEARCH THIS CLASS, SUBCLASS:
514 for signal reflector sealing from mois-ture or foreign particles.
838 for mirrors which reflect a substantial portion of incident light, but the re-flected light is not used for signalling purposes.

SEE OR SEARCH CLASS:
36, Boots, Shoes, and Leggings, subclass 137 for light reflecting or illumination at-tached to a shoe.
40, Card, Picture, or Sign Exhibiting, sub-class 208 for a license plate and reflector, subclass 219 for translucent mirrors with indicia, and subclasses 582+ for illuminated signs which may include reflective elements.
116, Signals and Indicators, subclass 20 for helios:graphic code signaling and subclasses 63+ for mechanical street traffic signalling structure, such as a semphore, light shutter, or pointer.
119, Animal Husbandry, subclass 858 for an animal collar including a reflector.
246, Railway Switches and Signals, subclass 474 for railway track reflectors which are disclosed as having special utility with railroads.
248, Supports, 201 for brackets and subclasses 466+ for mirror or picture type supports.
250, Radiant Energy, 483.1 for reflectors including luminescent, fluorescent or phosphorescent material.
264, Plastic and Nonmetallic Article Shaping or Treating Processes, subclass 1.9 for reflective type.
301, Land Vehicles: Wheels and Axles, subclass 37 for protectors or trim members.
313, Electric Lamp and Discharge Devices, 113 for an electric lamp or discharge device with a reflector integral therewith.
340, Communications: Electrical, appropri-ate subclasses for traffic and vehicle signal lights, 815.4 for visual indicator, and subclass 815.76 for lens type indicator.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Ra-dar, Radio Navigation), 5 for radar reflectors, i.e., reflectors of radio frequency waves.
362, Illumination, for artificial illumination means, 459 contains illumination with vehicle structure, subclasses 296+ for projectors with reflec-tors, and subclasses 341+ for constant reflectors.
404, Road Structure, Process, or Apparatus, 9 includes reflector support structure combined with road structure.
427, Coating Processes, 162 for optical element produced.
428, Stock Material or Miscellaneous Ar-ticles, subclass 98 for structurally de-fined web or sheet.

Body carried:
This subclass is indented under subclass 515. Subject matter including apparatus to enable a user (human or animal) to carry the reflector.
(1) Note. A reflector carried by the hand or wrist but not worn by the user, belongs in this subclass, rather than subclass 517.
(2) Note. The combination of either a flashlight or a cane with an attached reflector, which is normally carried by the hand, belongs in this subclass.
(3) Note. The combination of an article of clothing and a signal reflector belongs in this subclass not with the apparel of Class 2, since the combination only belongs in Class 2, if not otherwise classifiable.
(4) Note. The combination of an animal collar (i.e., nominal recitation of a collar or harness) together with a signal reflector is classified with the signal reflector not the collar of Class 119, subclass while a reflector claimed in combination with more than a nominal collar is classified in Class 119, subclass 858.

SEE OR SEARCH THIS CLASS, SUBCLASS:
517 for a signal reflector that is part of or attached to an article worn on the hand or wrist of the user.
518 for reflectors that are an integral part of the clothing used as apparel.
519 for reflectors that are worn over clothing, but not held.

SEE OR SEARCH CLASS:
36, Boots, Shoes, and Leggings, subclass 137 for light reflecting or illumination attached to a shoe.
63, Jewelry.
116, Signals and Indicators, subclass 35 for motion and direction indicators for vehicles.
119, Animal Husbandry, subclass 858 for an animal collar including a reflector.
340, Communications: Electrical, subclass 321 for portable self-contained (e.g., movie usher's signalling flashlight) and subclass 475 for turn signals.
362, Illumination, subclass 103 for wearing apparel or body support, subclass 104 for jewelry with wearing apparel or body support.

Worn by hand or wrist:
This subclass is indented under subclass 516. Subject matter wherein the reflector is a part of or attached to clothing or a device both of which are worn by the wrist or hand.
(1) Note. A glove having a reflector is classified in this subclass.
(2) Note. A wrist band having a reflector is classified in this subclass.
(3) Note. A reflector carried by the hand or wrist, but not worn, is classified in subclass 516.
(4) Note. Safety belts, pins, etc., wherein the sole function of the apparatus is to mount a signal reflector for safety purposes are classified in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
516 for reflectors that are carried by the body and not worn by the user.

SEE OR SEARCH CLASS:
2, Apparel, 158 for hand or arm covering.
36, Boots, Shoes, and Leggings, subclass 71.5 for preformed, externally applied, wear-connecting attachments.
63, Jewelry, 3 for bracelets and subclasses 15+ for finger rings.
362, Illumination, subclass 104 for jewelry with wearing apparel or body support.

Permanently fixed to clothing:
This subclass is indented under subclass 516. Subject matter wherein a reflector is attached to an article of clothing and remains on the clothing when a person discontinues wearing the clothing.
(1) Note. Signal reflectors that are part of the clothing a person wears and the clothing serves other purposes than as a mount for a reflector are classified in this subclass.
(2) Note. A belt, having a reflector, worn through the loops of a pair of trousers functions as an article of clothing and is classified and in this subclass.
(3) Note. Signal reflectors that are transparent spheres permanently fixed to clothing by glue, transparency, etc., are classified in this subclass.
(4) Note. A helmet, hat, shoe, or boot is considered clothing for this subclass, but Class 36, subclass 137 takes light reflecting or illumination attached to a shoe.
(5) Note. A pin with a reflector is not permanently fixed to clothing, but is classified in subclass 519.
(6) Note. A signal reflector permanently attached to an animal collar, leash, or harness is classifed in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
519 for safety belts, pins, etc., having a reflector and the sole purpose of wearing the article is for safety reasons. A safety belt is not worn through the loops of a pair of trousers.
538 for minute transparent reflective spheres mounted on a flexible substrate that is not clothing.

SEE OR SEARCH CLASS:
2, Apparel, 158 for hand or arm covering.
36, Boots, Shoes, and Leggings, subclass 71.5 for preformed, externally applied, wear-connected attachments.
63, Jewelry, 3 for bracelets and subclasses 15+ for finger rings.

Worn over clothing:
This subclass is indented under subclass 516. Subject matter wherein the reflector is mounted on apparatus that is placed over the apparel of a user.
(1) Note. This would include a safety belt, a safety belt harness, and pins that are worn solely for the reflecting properties not as part of the normal dress of the person. A safety belt is not used through the loops of a pair of trousers.

SEE OR SEARCH THIS CLASS, SUBCLASS:
516 for a signal reflector that is held by the user rather than worn.
518 for a belt used as an article of clothing for a pair of trousers which also has a reflector integral or as part of the belt.

SEE OR SEARCH CLASS:
2, Apparel, 158 for hand or arm covering.
36, Boots, Shoes, and Leggings, subclass 71.5 for preformed, externally applied, wear-connecting attachments.
63, Jewelry, 3 for bracelets and subclasses 15+ for finger rings.

Moving:
This subclass is indented under subclass 515. Subject matter where the signal reflector is in a continuous state of motion to be more easily observed.
(1) Note. The continuous state of motion could be vibration, oscillation, or rotation on a specified device whether or not they are "claimed" as rotating etc.
(2) Note. The motion of reflectors resulting from vehicle vibration, vehicle wheels, wind action, etc., are considered to be an irregular nature for this subclass and not periodic.
(3) Note. The beam deflection caused by a nonperiodic moving reflector solely to present a clearer observation of the reflector belong in this subclass not beam deflection by
the reflector to communicate some specific information via the modulation produced by the signal reflector beam deflection.
(4) Note. Rigidly mounted reflectors such as bicycle reflectors mounted on the frame do not belong here but in subclass 550.

SEE OR SEARCH THIS CLASS, SUBCLASS:
212 for a periodically moving reflector to produce light beam deflection/scanning without modulation.
508 for rotating reflector to throw off moisture or foreign particle.
526 for reflectors that are wobbly mounted on the support.
549 for reflectors rigidly mounted to a vehicle in order to move exactly as the vehicle.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, subclass 208 for a license plate and reflector, subclasses 427+ and 446+ for display devices that simulate motion or a changing exhibitor, subclasses 582+ for illuminated signs which may include reflective elements.
116, Signals and Indicators, 28 for vehicle, subclasses 46+ for rotatable motion and direction indicators for vehicles, and subclass 56 for vehicle-energy actuated.
246, Railway Switches and Signals, subclass 125 for electric automatic highway signals, mine doors, and gates.

Pedal mounted:
This subclass is indented under subclass 520. Subject matter wherein the reflector is attached to the pedal of a vehicle that requires pedal movement for vehicle motion.
(1) Note. These patents are generally bicycle pedals but are not limited only to bicycles.

SEE OR SEARCH THIS CLASS, SUBCLASS:
523 for spoke mounted moving reflectors.
524 for tire, valve stem, wheel, hub cap, or axle mounted moving reflectors.
550 for reflectors rigidly mounted to a bicycle or
motorcycle.

SEE OR SEARCH CLASS:
74, Machine Element or Mechanism, subclass 560 for pedals and subclasses 594.4 for pedals connected to a crank.

Rotating:
This subclass is indented under subclass 520. Subject matter wherein the reflector movement is rotational about some axis.
(1) Note. This includes reflectors that are rotated by the gases expelled from the exhaust pipe of a vehicle.
(2) Note. The structure of signs with the nominal recitation of a signal reflector are classified in Class 40. In particular, an "indicia" design or the conveyance of specific information would be classifiable in Class 40.

SEE OR SEARCH THIS CLASS, SUBCLASS:
508 for optical elements that are rotated for protection from moisture or foreign particles.
520 for reflectors that appear to move but are stationary and moving apertures in front of the reflectors make them appear to be moving.
525 for wind driven rotating reflectors.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, 430 for rotatable displays with special effects.
116, Signals and Indicators, 28 for vehicle, subclasses 46+ for rotatable motion and direction indicators for vehicles, and subclass 56 for vehicle-energy actuated.

Spoke mounted:
This subclass is indented under subclass 522. Subject matter wherein the reflector is attached onto one or more spokes that position the rim from the hub.
(1) Note. This subclass includes bicycle and motorcycle spokes as well as any other type of spoked wheel.

SEE OR SEARCH THIS CLASS, SUBCLASS:
521 for pedal mounted moving reflectors.
524 for tire, valve stem, wheel, hub cap, or axle mounted moving signal reflectors.
550 for reflectors rigidly mounted on a bicycle or motorcycle.

SEE OR SEARCH CLASS:
301, Land Vehicles: Wheels, and Axles, subclass 37 for wheel covers fastened to the spokes of a wheel.
340, Communications: Electrical, appropriate subclasses for bicycle traffic and vehicle communications.
362, Illumination, 473 with a bicycle or motorcycle supporting the illumination source.

Tire, wheel, valve stem, hub cap, or axle mounted:
This subclass is indented under subclass 522. Subject matter wherein the reflector is attached to either a rotating tire, valve stem, wheel, hub cap, or axle of a vehicle.
(1) Note. This also includes reflectors attached to or part of a dust cover of a valve stem.

SEE OR SEARCH THIS CLASS, SUBCLASS:
521 for pedal mounted moving reflectors.
523 for spoke mounted moving reflectors.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, subclass 587 for tire and wheel signs.
138, Pipes and Tubular Conduits, subclass 89.4 for inflation stem dust covers.
301, Land Vehicles: Wheels, and Axles, subclass 37 for wheel protectors or trim members, or wheel covers fastened to the spokes of a wheel, and subclass 108 for wheel hub caps.
340, Communications: Electrical, appropriate subclasses for bicycle traffic and vehicle communications.
362, Illumination, 473 with a bicycle or motorcycle
supporting the illumination source.

Wind driven:
This subclass is indented under subclass 522. Subject matter wherein the rotation of the reflector, attached to a vehicle, is controlled by wind.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, subclass 440 for rotatable fluid operated display with special effects and subclass 479 for rotatable fluid operated changing exhibitor.
116, Signals and Indicators, digest 7 for fluid actuated.
446, Amusement Devices: Toys, 217 for fluid driven rotatable blade (e.g., pinwheel).

Vibration:
This subclass is indented under subclass 520. Subject matter wherein the signal reflector attracts attention by its own random movement relative to its support.
(1) Note. This reflector is not driven by any motor or other source of energy such as the wheel of a vehicle or the wind.
(2) Note. The reflector is wobbly mounted with respect to its support.
(3) Note. The reflector has additional movement from that created by its support (i.e., it is suspended from its support bracket).
(4) Note. Reflectors rigidly mounted to a support via a helical or other spring belong in this subclass since they will vibrate.
(5) Note. A reflector attached to a mudflap of a vehicle would be classified here since the movement of the mudflap having the reflector attracts attention.
(6) Note. Rigidly mounted reflectors such as bicycle reflectors mounted on the frame do not belong here but in subclass 550.

SEE OR SEARCH THIS CLASS, SUBCLASS:
520 for reflectors that are in a continuous state of motion relative to their support.
549 for reflectors that are rigidly mounted on a moving vehicle.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, 613 for vibratory signs.

For a signal source remote from observer:
This subclass is indented under subclass 515. Subject matter including structure to reflect light from a signal originating from a source remote from the observer, i.e., not coming from a light source at the location of the observer.
(1) Note. This structure may be merely a plane mirror mounted on an automobile hood to reflect light from an overhead traffic signal to the driver or it may be a reflector at a street intersection which reflects light from the headlights of one car to the driver of another car travelling in a direction approximately 90 degrees different than that of the first car.
(2) Note. Road reflectors remote from the vehicle, to reflect all of an automobile's headlight beams back to the driver are not classified in this subclass since the source of the vehicle headlight beams are at the location of the observer.
(3) Note. The reflection of the light beams of one vehicle's headlights to another vehicle would be classified in this subclass.
(4) Note. A reflector which reflects a portion of the light output of a vehicle's headlight or taillight to be observable by the driver of the vehicle is classified in this subclass, rather than Class 362, since the reflection is for observation rather than illumination.

SEE OR SEARCH THIS CLASS, SUBCLASS:
529 for 3 corner retroreflectors which return a light beam back to the source.
531 for unitary retroreflectors mounted on the road surface.
546 for plural reflecting elements for a single sheet or
plate such as in some road reflectors.
551 for reflectors mounted on the roadway that reflect the light from a vehicle back to the driver of the vehicle.
552 for reflectors mounted adjacent the roadway which reflect the light beams from a vehicle's headlights back to the driver of the vehicle.
838 for similar mirrors which are not dis-closed as signal mirrors, which only have to reflect light, but which are disclosed as reflecting images.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, subclass 559 for illuminated sign external light source if indicia is present.
246, Railway Switches and Signals, subclass 474 for track reflectors. A railway and switch in combination with a nominally recited signal reflector are also classified in this class (246).
248, Supports, 476 for adjustable mirror or picture position.
296, Land Vehicles: Bodies and Tops, subclass 97.1 for glare or screen body and subclass 97.2 for specific structure or properties for diffusing or reflecting light to reduce the glare on the viewer's eyes.
362, Illumination, 341 for a reflector light modifier.
404, Road Structure, Process, or Appara-tus, subclass 16 for reflectors used to detect the presence of traffic.

Light transmitting from source behind a reflector:
This subclass is indented under subclass 515. Subject matter where the reflector is adapted to transmit light from a source which is behind the surface of the reflector which is normally viewed, such as in a tail-light reflector which transmits light from a light bulb behind the reflector or lens and also reflects a large amount of light which is directed to the front surface of the reflector by an external source such as the headlights of an approaching automobile.
(1) Note. The patents of this subclass use a signal reflector combination with a light source behind the reflector in order to attract attention of other vehicles, either by the light source itself or reflection of the other vehicle's light.
(2) Note. The use of a reflector to change (i.e., concentrate, disperse, collimate) the light from a source for illumination purposes belong in Class 362 (e.g., the reflector behind the light source of a headlight used to direct the outgoing beam in a particular pattern).

SEE OR SEARCH THIS CLASS, SUBCLASS:
549 for a taillight that reflects incoming light from a reflector behind the light source that transmits away from the vehicle.

SEE OR SEARCH CLASS:
362, Illumination, 459 for illumination with vehicle structure, subclass 494 for mirror or reflector with vehicle structure (e.g., rear view mirror), subclasses 296+ for a light source and modifier including a reflector where the reflector is used to modify the outgoing source light beam, and subclasses 341+ for reflector light modifiers.
428, Stock Material or Miscellaneous Articles, subclass 31 for vehicle body ornament.

3-Corner retroreflective (i.e., cube corner, trihedral, or triple reflector type):
This subclass is indented under subclass 515. Subject matter wherein the light is reflected from three reflecting surfaces and wherein after the three reflections, it moves in a direction opposite to and parallel to its direction before the three reflections.
(1) Note. The reflections may be external or internal, i.e., the light may be reflected without entering the material from which the reflector is made or the light may enter one surface of the reflector, be reflected three times internally, and exit through the same sur-face.
(2) Note. Single or plural 3-corner reflectors are classified in this subclass but plural reflectors formed into a single substrate are classified in subclass 530.

SEE OR SEARCH THIS CLASS, SUBCLASS:
527 for a structure which reflects light from a signal source remote from an observer.
530 for plural 3-corner reflectors in a single substrate.
831 for prisms, per se.

SEE OR SEARCH CLASS:
65, Glass Manufacturing, 357 for a mold with separating or clamping.
72, Metal Deforming, 379.2 for deforming sheet metal.
204, Chemistry: Electrical and Wave Energy, subclass 281 for electroforming mold or strips, plates, electrodes apparatus for forming electrolytic elements.
228, Metal Fusion Bonding, 141.1 for the process of shaping.
249, Static Molds, subclass 117 for container type molding device.
264, Plastic and Nonmetallic Article Shaping or Treating: Processes, subclass 1.9 for reflective composite or multilayer optical article shaping or treating.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation), 7 for radio wave cube corner reflectors.
425, Plastic Article or Earthenware Shaping or Treating: Apparatus, subclass 403 for shaping surfaces, per se, and subclass 808 for lens mold.

Unitary plate or sheet comprising plural reflecting elements:
This subclass is indented under subclass 529. Subject matter wherein the reflective elements, such as the individual triple reflectors, are part of a single plate or sheet comprising a plurality of the 3-corner reflective elements.
(1) Note. The reflective elements are a part of the structure of the plate or sheet.
(2) Note. Many of these retroreflectors are used on highways for road makers.
(3) Note. Plural reflectors combined into a single substrate are classified in this subclass whereas plural reflectors using multiple substrates are classified in subclass 529.

SEE OR SEARCH CLASS:
65, Glass Manufacturing, 357 for a mold with separating or clamping.
72, Metal Deforming, 379.2 for deforming sheet metal.
204, Chemistry: Electrical and Wave Energy, subclass 281 for electroforming mold or strips, plates, electrodes apparatus for forming electrolytic elements.
228, Metal Fusion Bonding, 141.1 for the process of shaping.
249, Static Molds subclass 117 for container type molding device.
264, Plastic and Nonmetallic Article Shaping or Treating: Processes, subclass 1.9 for reflective composite or multilayer optical article shaping or treating.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation), 7 for radio wave cube corner reflectors.
404, Road Structure, Process, or Apparatus, subclass 14 for lane marker impregnated with reflective material, subclass 16 for vibration inducing member including a reflector.
425, Plastic Article or Earthenware Shaping or Treating: Apparatus, subclass 403 for shaping surfaces, per se, and subclass 808 for lens mold.

Mounted on roadway:
This subclass is indented under subclass 530. Subject matter wherein the reflector is positioned onto the vehicle road surface in order to enable easier viewing of that portion of the roadway.
(1) Note. A reflector sign, having a unitary plate of 3-corner reflectors, permanently fastened to a road surface would belong in this subclass but the same reflector counterbalanced within a recess in the roadway - ordinarily up and visible but capable of retraction into the recess when contacted by the vehicle wheel - is classified in Class 404.

SEE OR SEARCH THIS CLASS, SUBCLASS:
514 for signal reflector sealing from moisture or foreign particle.
547 for a unitary mass of discrete reflecting elements mounted on or adjacent the roadway.
551 for a broad reflector mounted on the roadway.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, subclass 612 for highway or street marker.
180, Motor Vehicles, subclass 168 having controlling apparatus adapted to interact with stationary apparatus which describes the course of the vehicle's travel.
404, Road Structure, Process, or Apparatus, 9 for traffic director where the reflector is not permanently fixed to the road surface.

Mounted adjacent roadway:
This subclass is indented under subclass 530. Subject matter wherein the reflector is positioned off of the roadway surface but within viewing distance of the driver of a vehicle in order to enable easier viewing of the edge of the roadway.
(1) Note. A reflector sign permanently fastened to a road surface would belong in this subclass but the same reflector counterbalanced within a recess in the roadway - ordinarily up and visible but capable of retraction into the recess when contacted by the vehicle wheel is classified in Class 404.

SEE OR SEARCH THIS CLASS, SUBCLASS:
514 for signal reflector sealing from moisture or foreign particle.
547 for a unitary mass of discrete reflecting elements mounted on or adjacent the roadway.
552 for a broadly recited reflector mounted adjacent the roadway.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, subclass 612 for highway or street marker.
116, Signals and Indicators, 63 for street traffic where the device for giving signals are generally due to some movement of some part or element from a normal or nonsignalling or signal-controlled position (e.g., a semaphore).
180, Motor Vehicles, subclass 168 having controlling apparatus adapted to interact with stationary apparatus which describes the course of the vehicle's travel.
404, Road Structure, Process, or Apparatus, 9 for traffic director where the reflector is not permanently fixed to the
road surface.

Mounted on vehicle:
This subclass is indented under subclass 530. Subject matter wherein the reflector is positioned on a vehicle.
(1) Note. This vehicle could be an airplane, boat, automobile, train, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:
548 for discrete reflecting elements formed as a unitary mass mounted on a vehicle.
549 for broadly recited reflectors mounted on a vehicle.

Including a curved refracting surface:
This subclass is indented under subclass 515. Subject matter including a surface which is curved and which refracts or bends the light before or after it is reflected.
(1) Note. The reflector operates as a separate function and is located behind the actual curved refracting surface.

SEE OR SEARCH THIS CLASS, SUBCLASS:
546 for reflecting elements formed as a unitary piece.
642 for lenses generally, and especially subclasses 727+ for lenses including concave or convex reflecting surfaces.

Within individual indentations:
This subclass is indented under subclass 534. Subject matter wherein the curved refracting surface is positioned either within an indentation of the substrate or within a socket created by a plurality of elements to hold it in place.
(1) Note. Multiple minute spheres used to retain a much larger curved refracting optical element within a socket for the larger element belong in this subclass.
(2) Note. These indentations can be produced by a platen
which forces refracting beads against a substrate to form indentations, thus producing separate indentations for each bead.

SEE OR SEARCH THIS CLASS, SUBCLASS:
543 for individual reflector (not microsphere) element mount.

Minute transparent spheres:
This subclass is indented under subclass 534. Subject matter where the elements which refract and reflect are tiny transparent spheres, commonly called "little glass beads".
(1) Note. The elements may be partially or fully embedded. The matrix may be attached to a surface of any shape such as a spherical or a flat surface.
(2) Note. These spheres range in size between 3-6 mils (i.e., 0.003 - 0.006 inches).

SEE OR SEARCH THIS CLASS, SUBCLASS:
539 for a mixture of spheres in a liquid binder (e.g., paint or resin).
540 for spheres placed on top of a binder (e.g., resin, asphalt, glue).

SEE OR SEARCH CLASS:
501, Compositions: Ceramic, subclass 34 for reflective glass beads.
523, Synthetic Resins or Natural Rubbers, subclass 219 for process of forming glass void.

Directional reflection (e.g., prevent viewing unless critical angle of light is used):
This subclass is indented under subclass 536. Subject matter wherein the reflective structure behind the spheres is arranged to permit viewing of the image behind the spheres, only if the incident light is transmitted to the spheres at the desired critical angle.
(1) Note. The directional reflection of this subclass permits viewing of the image only by those authorized (i.e.,
knowing the angle).
(2) Note. The image is not changed by the directional reflection but observation is accomplished dependent upon viewing at the proper angle.
(3) Note. A picture that is covered by a substrate containing minute glass spheres to permit viewing of the picture via the reflected light only if the incident light is at a predetermined angle belongs in this subclass.

SEE OR SEARCH CLASS:
380, Cryptography, subclass 54 for modifying optical image (e.g., transmissive overlay) by changing its visible appearance.

On flexible substrate (e.g., flexible sheeting, bumper sticker, etc.):
This subclass is indented under subclass 536. Subject matter wherein the spheres are placed on a flexible material by transfer, glue, etc., and this material can be used for an reflective purpose.
(1) Note. Spheres embedded in a resin that remains flexible (e.g., elastomeric composition) are classified in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
518 for signal reflectors (e.g., transparent spheres, etc.) permanently fixed to clothing (e.g., by glue, transparency, etc.).

SEE OR SEARCH CLASS:
2, Apparel, for apparel, per se.

Mixture in liquid binder (e.g., paint, resin):
This subclass is indented under subclass 536. Subject matter wherein the spheres are located within the mixture of paint or resin and are simultaneously applied to the surface as a complete mixture.
(1) Note. This mixture can be painted onto signs, vehicles, or roadway surfaces.

SEE OR SEARCH THIS CLASS, SUBCLASS:
540 for spheres that are placed on top of a binder prior to the hardening of the binder.
551 for reflective paint that does not have minute spheres.

SEE OR SEARCH CLASS:
106, Compositions: Coating or Plastic, subclass 228 and 253 for a natural resin or derivative containing filler, dye, or pigment.
523, Synthetic Resins or Natural Rubbers, subclass 527 for glass DNRM nonreactive material mixed with a composition.

Placed on top of binder (e.g., resin, asphalt, glue, etc.):
This subclass is indented under subclass 536. Subject matter wherein the binder is first placed on the surface and subsequently, prior to hardening of the binder, the spheres are placed thereon to ensure that they are fixed to the surface via the binder.
(1) Note. This includes exposed spheres which are glued to the surface, resulting in an exposed glass-sphere surface.
(2) Note. Spheres which are not completely surrounded by the binder belong in this subclass.
(3) Note. A monolayer (single) of spheres on a binder belong in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
539 for spheres which are completely surrounded by the binder.

With single transparent coating between spheres and atmosphere:
This subclass is indented under subclass 540. Subject matter wherein a single coating, which is transparent to light, surrounds and either (1) completely envelopes the normally exposed surface of the sphere, (2) touches only a portion of the spheres, or (3) is an interface for the minute spheres where the spheres are confined but not touching the exposed surface.
(1) Note. This single coating will cover the sphere relative to the environment yet have no optical effect on the light that would impinge on a normally exposed surface of the sphere. If reference is made to protection of the reflector from moisture or foreign particle it belongs in subclass 514.
(2) Note. A transparent coating used simply to hold the spheres onto the binder is not considered a sealer as in subclass 514.

SEE OR SEARCH THIS CLASS, SUBCLASS:
514 for a sealed signal reflector to protect it from moisture or foreign particle.

SEE OR SEARCH CLASS:
428, Stock Material or Miscellaneous Articles, subclass 34 for light transmissive sheets with gas space therebetween and edge sealed (e.g., double glazed storm window, etc.).

Plural refracting elements formed as a unitary mass:
This subclass is indented under subclass 534. Subject matter including a unitary mass of transparent material which comprises a plurality of curved refracting sur-faces.
(1) Note. This unitary mass performs refraction of the incoming light prior to reflection by the reflector, and also of the outgoing light after reflection.

SEE OR SEARCH THIS CLASS, SUBCLASS:
454 for projection screens having a unitary sheet of plural refracting areas.
530 for plural cube corner reflectors which together make up a unitary plate.
546 for discrete reflecting elements which comprise a unitary mass.

With individual reflector element mount:
This subclass is indented under subclass 534. Subject matter including means for mounting the individual optical elements such as small socket-like mounts in which the elements are inserted and held or further including means for mounting the
small socket-like mounts.
(1) Note. Reflector buttons that simply reflect light falling on them, autocollimating, without the creation of a single image of an object at a focal point are classified in this subclass rather than the lens subclasses of this class.
(2) Note. Although reflector buttons are often called "lenses" they are not classified in the lens subclasses of this class unless they create a single image of an object at a focal point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
535 for minute transparent spheres within individual indentations.
546 for a multifaceted single glass reflector which is considered a unitary mass of discrete reflecting elements.
642 for lenses, per se.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, 201 for a license plate with a theft-preventive feature.
404, Road Structure, Process, or Apparatus, 9 for reflector support structure combined with road structure.

Including a snap, spring clip, or spring retainer:
This subclass is indented under subclass 543. Subject matter wherein either the curved refracting surface or the reflecting surface behind the refractor are individually mounted on a support by being pushed into a retainer which opens for entrance and closes around a portion of the element when it is in the settled position or a coil spring holds each element in place.
(1) Note. The snap or spring clip retainer could either clamp onto the refractor/reflector or could be used to clamp a retainer to a housing and the refractor/reflector force fitted into the retainer. The combination of a refractor/reflector and a retainer that is snapped into a third device belong in this subclass.
(2) Note. A rubber slot into which the refractor or reflector are pushed into for retention in the slot belong in subclass 543.
(3) Note. Although the reflector buttons of this subclass are often referred to as lenses, these have not been crossed
into lenses since these simply reflect the light falling on them rather than create a single image of an object at a focal point. These buttons are often referred to as auto collimating.

SEE OR SEARCH THIS CLASS, SUBCLASS:
545 for a mount using a threaded member.

SEE OR SEARCH CLASS:
248, Supports, subclass 27.3 for holding an instrument in a panel by a biased clip.
267, Spring Devices, subclass 159 for a snap spring and subclasses 166+ for coil springs.

Including a threaded member:
This subclass is indented under subclass 543. Subject matter where the means for mounting includes a threaded member for screw attachment and this can be used to mount the curved refracting surface that is located in fron of the reflecting surface.
(1) Note. Reflector buttons that simply reflect light falling on them, autocollimating, without the creation of a single image of an object at a focal point are classified in this subclass rather than the lens subclasses of this class.
(2) Note. Although reflector buttons are often called "lenses" they are not classified in the lens subclasses of this class unless they create a single image of an object at a focal point.

SEE OR SEARCH CLASS:
411, Expanded, Threaded, Driven, Headed, Tool-Deformed, or Lock-Threaded Fastener, 81 for threaded fastener and means for restricting rotation thereof relative to coacting substructure.

Discrete reflecting elements formed as a unitary mass:
This subclass is indented under subclass 515. Subject matter wherein a plurality of reflective elements are each part of a unitary plate or sheet.
(1) Note. This unitary mass performs the actual reflection
of the incoming beam.
(2) Note. This includes a single glass reflector having multiple facets.
(3) Note. The individual reflectors are arranged to reflect light as if it came from one single reflector having a particular characteristic.

SEE OR SEARCH THIS CLASS, SUBCLASS:
459 for a unitary sheet comprising plural reflecting elements on a projection screen.
527 for reflectors that reflect headlight beams to the eyes of the driver.
529 for retroreflective reflectors that reflect the light directly to the source of the light.
530 for a plurality of triple reflectors which are each part of a unitary plate or sheet.
542 for a plurality of signal reflectors with a curved reflecting and a curved refracting surface which are each part of a unitary plate or sheet.

Mounted on or adjacent roadway:
This subclass is indented under subclass 546. Subject matter wherein the unitary mass is positioned either on or off of the roadway surface within viewing distance of the driver of a vehicle in order to enable an easier view of that portion of the roadway or the edge of the roadway.
(1) Note. A reflector sign, having discrete reflecting elements, permanently fastened to a road surface would belong in this subclass but the same reflector counterbalanced within a recess in the roadway - ordinarily up and visible but capable of retraction into the recess when contacted by the vehicle wheel is classified in Class 404.

SEE OR SEARCH THIS CLASS, SUBCLASS:
514 for signal reflector sealing from mois-ture or foreign particle.
531 for a unitary plate of 3-corner reflectors mounted on the roadway.
532 for a unitary plate of 3-corner retrore-flectors mounted adjacent the roadway.
551 for a broad reflector mounted on the roadway.
552 for a broadly recited reflector mounted adjacent the roadway.

SEE OR SEARCH CLASS:
40, Card, Picture, or Sign Exhibiting, subclass 612 for highway or street marker.
116, Signals and Indicators, 63 for street traffic where the device for giving signals are generally due to some movement of some part or element from a normal or nonsignalling or signal-controlled position (e.g., a semaphore).
404, Road Structure, Process, or Apparatus, 9 for traffic director where the reflector is not permanently fixed to the road surface.

Mounted on vehicle:
This subclass is indented under subclass 546. Subject matter wherein the unitary mass is positioned on a vehicle.
(1) Note. This vehicle could be an airplane, boat, automobile, train, etc.
(2) Note. This includes a single glass reflector having multiple facets.

SEE OR SEARCH THIS CLASS, SUBCLASS:
533 for a unitary plate of 3-corner retroreflectors mounted on a vehicle.
549 for broadly recited reflectors mounted on a vehicle.

Rigidly mounted on vehicle:
This subclass is indented under subclass 515. Subject matter wherein the reflector is rigidly attached to any type of vehicle used to carry passengers.
(1) Note. This vehicle could be an airplane, boat, automobile, train, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:
520 for reflectors that are in a continuous state of motion
relative to a vehicle.
526 for reflectors that attract attention by the random movement with respect to the support.
533 for a unitary plate of 3-corner retroreflectors mounted on a vehicle.
548 for discrete reflecting elements formed as a unitary mass mounted on a vehicle.

Bicycle or motorcycle:
This subclass is indented under subclass 549. Subject matter wherein the vehicle is a two wheeled vehicle in the form of either a bicycle or motorcycle.

SEE OR SEARCH THIS CLASS, SUBCLASS:
521 for pedal mounted reflectors.
523 for spoke mounted reflectors.