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 ro