CPC Definition - Subclass G02B

Last Updated Version: 2021.01
OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS (G02F takes precedence; measuring instruments, see the relevant subclass of G01, e.g. optical rangefinders G01C; testing of optical elements, systems, or apparatus G01M 11/00; spectacles G02C; sound lenses G10K 11/30; electron and ion "optics" H01J; X-ray "optics" H01J, H05G 1/00; optical elements structurally combined with electric discharge tubes H01J 5/16, H01J 29/89, H01J 37/22; microwave "optics" H01Q; combination of optical elements with television receivers H04N 5/72; heating arrangements specially adapted for transparent or reflecting areas H05B 3/84)
Definition statement

This place covers:

Passive optical elements and systems, i.e. elements and systems which are not based on the optical properties of the material used being altered by the application of an external field.

In particular:

  • Optical elements characterised by the material of which they are made
  • Simple or compound lenses
  • Optical elements other than lenses (e.g. prisms, diffusers, mirrors, diffraction gratings, filters, polarisers)
  • Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings (Note: to be dealt with in a further FCR document relating to G02B 6/00)
  • Mountings, adjusting means, or light-tight connections, for optical elements
  • Optical objectives or lens systems characterised both by the number of the optical components and their arrangements according to their sign, i.e. + or -
  • Optical objectives specially designed for specific purposes
  • Optical objectives with means for varying the magnification, e.g. zoom lenses
  • Systems with reflecting surfaces, with or without refracting elements, i.e. catadioptric or catoptric systems
  • Optical condensers
  • Microscopes
  • Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies
  • Eyepieces (e.g. for telescopes, microscopes); Magnifying glasses
  • Optical devices or arrangements using movable or deformable optical elements
Relationships with other classification places

Whereas G02B relates to passive optics, "active" optics, i.e. where the optical properties of the material used in the optical device are altered by the application of an external field, e.g. electro-optical devices, magneto-optical devices, LCDs, is covered by G02F.

References
Limiting references

This place does not cover:

Ophthalmic lenses, e.g. spectacles

G02C

Devices or arrangements, the optical operation of which is modified by changing the optical properties of the medium of the devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light; Non-linear optics; Optical logical elements; Optical analogue / digital converters

G02F

Microwave and Terrahertz optics

H01Q

Application-oriented references

Examples of places where the subject matter of this place is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Medical endoscopes

A61B 1/00

Surgical microscopes

A61B 90/36

Optical elements specially adapted for use in lighting devices or systems thereof

F21V 1/00
-F21V 13/00

Refractors for light sources

F21V 5/00

Reflectors for light sources

F21V 7/00

Filters for light sources

F21V 9/00

Optical rangefinders

G01C

Apparatus or arrangements for taking photographs or for projecting or viewing them

G03B

Optics integrated in LED packages

H01L 33/58

Optics of laser cavities

H01S

Combination of optical elements with television receivers

H04N 5/72

Heating arrangement for transparent or reflecting areas

H05B 3/84

Informative references

Attention is drawn to the following places, which may be of interest for search:

Hand, pocket, or shaving mirrors

A45D 42/00

Household mirrors

A47G 1/00

Apparatus for testing the eyes

A61B 3/00

Treatment for or protection of the eyes, e.g. protective goggles

A61F 9/00

Optical toys

A63H 33/22

Applying liquid films, e.g. spin coating

B05D 1/00

Working by laser beam, e.g. welding, cutting or boring

B23K 26/00

Grinding or polishing lenses or gratings

B24B 13/00

Producing optical elements from plastics

B29D 11/00

Layered products

B32B

Printing using a scanning light deflector

B41J 2/471, G06K 15/12

Diffractive or holographic structures on credit cards

B42D 25/00

Vehicle mirrors, e.g. rear-view or side-view

B60R 1/00

Optical micromechanical [MEMS] devices

B81B

Pressing lenses from molten glass

C03B 11/08

Surface treatment of glass by coating

C03C 17/00

Liquid crystals per se

C09K 19/00

Coating in general, e.g. CVD or sputtering

C23C

Supports, stands or frames in general

F16M

Solar heat collectors

F24S

Sighting devices for weapons

F41G 1/00

Interferometers

G01B 9/02

Measuring microscopes

G01B 9/04

Surveying

G01C

Spectrometry

G01J 3/00

Testing of optical systems

G01M 11/00

Optical benches

G01M 11/04

Investigating or analysing materials by the use of optical means

G01N 21/00

Scanning probe techniques, e.g. near field microscopy

G01Q

Systems using reflection of light e.g. lidar

G01S 17/00

Spectacles, sunglasses or contact lenses

G02C

Liquid crystal displays [LCDs]

G02F 1/13

Photography

G03B

Projection screens

G03B 21/56

Photosensitive materials

G03C 1/00

Photolithography

G03F 7/00

Fourier/Laplace transform optics, correlation

G06E 3/003

Optics of barcode scanners

G06K 7/10831

Laser printers

G06K 15/12, B41J 2/471

Record carriers with diffractive or holographic structures

G06K 19/16

Holograms on banknotes

G07D 7/0032

Control arrangements or circuits for displays other than CRTs

G09G 3/00

Sound lenses

G10K 11/30

Recording or reproducing by optical means, e.g. optical disks

G11B 7/135

Adjusting position or attitude, e.g. level, of instruments

G12B 5/00

Casings; Housings; Cabinets; Supports etc.

G12B 9/00

X-ray optics, gamma ray optics

G21K 1/06

Electron and ion focusing devices; X-ray "optics"

H01J

Plasma display panels

H01J 17/49, H01J 2217/49292

Optical arrangements associated with CRTs, e.g. AR means

H01J 29/89

Electron or particle beam optics, e.g. electron microscopes

H01J 37/00

Electroluminescent OLED displays

H01L 27/32

Light concentrating means for solar cells

H01L 31/054

Optics of microwaves or millimetre waves

H01Q 15/00

Wavelength division multiplexing [WDM] systems

H04J 14/02

Facsimile transmission

H04N 1/00

TV cameras

H04N 5/225

Projection TV

H04N 5/74

Colour projection TV

H04N 9/3197

Stereoscopic TV

H04N 13/00

X-ray technique

H05G

Special rules of classification

Indexing Codes in general:

Classification of additional information is mandatory. E.g., a document describing the detailed structure of a wire grid polarizer should be classified in G02B 5/3058, whereas a document describing a display system making explicit use of a wire grid polarizer without providing structural details of the polarizer itself should be given in G02B 5/3058 as an additional invention symbol.

Indexing Codes special cases (the following additional sets of Indexing Codes are used):

  • The set of Indexing Codes G02B 2207/00 - G02B 2207/129 provide classification entries for "orthogonal" features, i.e. features which may arise in the field in general.
  • The set of Indexing Codes under G02B 27/01 provide classification entries to cover further details of subject matter covered by G02B 27/01 and not provided for in its subgroups.
Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Optics, optical

Infrared, visible or ultraviolet optics

Active optics

Optics based on the optical properties of a material used being altered by the application of external energy, e.g. electrical, magnetic, thermal or optical energy

Passive optics

Optics in which the optical properties of a material used are not altered by the application of external energy; external forces may act, however, to alter the shape, position or orientation of an optical element used.

Catoptric

Optical systems involving reflective surfaces only

Catadioptric

Optical systems involving reflective and refractive surfaces

simple lens or prism

single lens or prism; simple lens, simple; lenses, simple prism; simple prisms, simple; Single lens; prism

compound lens or prism,compound lens, compound lenses, compound prism, compound prisms

Optical member the constituents of which are either close together without air-space or in broken contact; see also the Note after group G02B.

objective, objectives

Lens or optical system designed to produce a real image of a real object.

Eyepiece, Eyepieces

Lens or optical system designed to produce a virtual image for viewing by the eye or by another optical system

Front, rear

is determined by looking from the more distant conjugate

in broken contact

such that the air-space between the constituents of an optical member has no essential optical influence

Essential

Fundamental

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

LCD

Liquid Crystal Display

MEMS

Microelectromechanical System

DMD

Digital Micromirror Device

Optical elements characterised by the material of which they are made (compositions of optical glasses C03C 3/00; cements for glass C03C 27/00)
Definition statement

This place covers:

Optical elements characterised by the material of which they are made.

References
Limiting references

This place does not cover:

Composition of optical glasses

C03C 3/00

Cements for glass

C03C 27/00

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

CVD

Chemical Vapour Deposition

PVD

Physical Vapour Deposition

Optical coatings produced by application to, or surface treatment of, optical elements (G02B 1/08 takes precedence)
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Reflection coatings

G02B 5/08

Coating of glass in general

C03C 17/00

having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Surface plasmon devices

G02B 5/008

Anti-glare structures

G02B 5/08

by surface treatment, e.g. by irradiation
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Surface treatment of glass by irradiation

C03C 23/0005

Simple or compound lenses (artificial eyes A61F 2/14; spectacle lenses or contact lenses for the eyes G02C; watch or clock glasses G04B 39/00)
Definition statement

This place covers:

Simple or compound lenses including arrays.

References
Limiting references

This place does not cover:

Artificial eyes

A61F 2/14

Ophthalmic lenses

G02C

Watch or clock glasses

G04B 39/00

Optical elements other than lenses (light guides G02B 6/00; optical logic elements G02F 3/00)
Definition statement

This place covers:

Optical elements other than lenses, e.g. prisms, diffusers, mirrors, diffraction gratings, filters, polarisers,light absorbing elements, diaphragms, surface plasmon devices or birefringent or phase retarding elements

Relationships with other classification places

Filters for plasma panel displays are classified under H01J and in H01J 2217/49292. A further classification in G02B 5/20 is optional.

References
Limiting references

This place does not cover:

Light guides

G02B 6/00

Optical logic elements

G02F 3/00

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Mirror

device for which the essential characteristic is maximum reflectivity over a given spectral range. A reflecting layer in a mirror is defined as a layer adapted to play a role in the reflection of light, and thus it does not refer to other layers having essentially no reflective function, e.g. protective layers

Filter

device for which the essential characteristic is spectral selectivity, i.e. not only the spectral range passed (for example, by transmission, reflection) but also the spectral range rejected (for example, by absorption, transmission, reflection)

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

FSS

frequency selective surface

Prisms
Definition statement

This place covers:

Optical elements being prisms

Mirrors {(vehicle mirrors involving special optical features B60R 1/08)}
Definition statement

This place covers:

Optical elements being mirrors

References
Limiting references

This place does not cover:

Vehicle mirrors as such

B60R 1/08

{in which spectral selection is performed by means of a conductive grid or array, e.g. frequency selective surfaces (for use with wavelengths longer than the infra-red light H01Q 15/0006)}
Definition statement

This place covers:

Filters in which the spectral filtering is performed by a conductive grid or mesh. The background is that for microwave optics, there has long existed a technique in which a conductive periodic pattern (a so-called "frequency selective surface" or FSS) is used to select a particular set of frequencies. For microwaves they are found in the subgroup H01Q 15/0006. In recent years this technique has been extended to IR and even visible wavelengths. It is these types of filters (and only these) which should go into G02B 5/204. Basically they look something like this:

media0.png

References
Limiting references

This place does not cover:

Frequency filtering for aerials

H01Q 15/0006

Special rules of classification

G02B 5/204 is not to be used for classifying normal spectral filters which just happen to have some additional conducting elements for other purposes not to do with spectral selection. In particular it is not for filters having a conductive EM shielding layer or a conductive louvre light blocking grid attached. For such arrangements, the following places may be appropriate:

Interference filters
References
Application-oriented references

Examples of places where the subject matter of this place is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Use of dichroic reflectors in lighting devices

F21V 7/22

Use of dichroic filters in lighting devices

F21V 9/20

Holograms used as optical elements
References
Application-oriented references

Examples of places where the subject matter of this place is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Scanning systems using holograms, e.g. holographic scanners

G02B 26/106

Informative references

Attention is drawn to the following places, which may be of interest for search:

Processes or apparatus for producing holograms

G03H

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

HOE

Holographic optical element

Light guides
Definition statement

This place covers:

Light guides per se, coupling light guides and mechanical protection of light guides.

The term "light" as used in G02B 6/00 refers to visible, infrared and ultraviolet light only.

The group covers the optical and mechanical aspects of light guides and light guide coupling, including the coupling of light into, out of and between light guides, as well as positioning, holding and protecting the light guides. This includes optical cables and arrangements for handling optical cables. The group covers the manufacture of some light guides, in particular optical waveguides of the integrated circuit kind.

The group covers light guides for illumination.

Light guides occur in many areas of technology. To avoid unnecessary double classification, the implementation of light guides in optical systems and instruments for which specific entries exist elsewhere (for example in surgical instruments or for chemical sensing) are not generally given a secondary class in G02B 6/00. This applies particularly to systems and instruments where light guide use is well established. The brief mention of a light guide does not in itself justify classifying in G02B 6/00. Exceptionally, where an optical aspect of the light guide coupling of general interest is disclosed, such a secondary class may be given. A class in G02B 6/00 is always given where a passive light guide per se has been specially adapted.

Relationships with other classification places

"Active" optics, i.e. where the optical property of the light guide or of an optical element coupled to the light guide is altered by the application of an external field are classified in G02F. Backlights characterised by the light guides for liquid crystal display panels are classified in G02B 6/0001 - G02B 6/0096.

Light amplifying light guides are classified in H01S.

Systems for communication are classified in H04, in particular optical transmission systems in general are classified in H04B 10/00, optical multiplex systems are classified in H04J 14/00, and optical switching systems are classified in H04Q 11/0001. Network and system aspects are classified in H04 and not in G02B 6/00. Light guide arrangements as components, modules or subsystems of communication systems are classified in G02B 6/00: "in the box" aspects are classified in G02B 6/00. For example modules based on light guides for coupling, splitting, mixing, switching and dispersion compensation are classified in G02B 6/00.

References
Application-oriented references

Examples of places where the subject matter of this place is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Endoscopes using optical fibres for illumination

G02B 23/2469

Endoscopes with light guides

G02B 23/26

Medical endoscopes

A61B 1/00

Surgical instruments

A61B 18/22

Devices for illuminating a surgical field

A61B 90/36

Sensing by attenuation

G01D 5/353

Measuring temperature using optical fibre gratings

G01K 11/3206

Measuring force or strain using an optical fibre

G01L 1/246

Investigating or analysing materials

G01N 21/00

Informative references

Attention is drawn to the following places, which may be of interest for search:

Organic materials for light guides

G02B 1/045

Christmas trees

A47G 33/04

Manufacture of plastic optical fibres

B29D 11/00663

Manufacture of glass optical fibres

C03B 37/01

Glass compositions for optical fibres

C03C 13/04

Process of coating of optical fibres

C03C 25/10

Surveying of bore holes

E21B 47/135

Variable effect lighting

F21S 10/005

Measuring vibrations or sonic waves

G01H 9/004

Testing of light guide systems

G01M 11/30

Indicating arrangements using optical fibre ends

G09F 9/305

Scanners with light guides for illumination

H04N 1/02855

Special rules of classification

The primary protective coating immediately surrounding the cladding of an optical fibre is considered to be a component of an optical fibre and is thus classified in the G02B 6/02 subgroup. Further layers around the optical fibre are considered to form optical cables and are thus classified in G02B 6/44 and subgroups. This definition is also used to decide on the subgroup to be used for classifying a coupling. For example a clamp for an optical fibre is classified in G02B 6/36 whereas a clamp for an optical cable is classified in G02B 6/4471.

Light guides for illumination

G02B 6/0001 - G02B 6/0096

Optical fibres with or without a coating

G02B 6/02 - G02B 6/08 , G02B 6/102, G02B 6/105, G02B 6/14

Waveguides of the integrated circuit kind

G02B 6/12 - G02B 6/14, G02B 6/102, G02B 6/105, G02B 6/107

Subwavelength diameter waveguides

G02B 6/107

Other waveguides

G02B 6/10

Optical cables

G02B 6/44 - G02B 6/4438, G02B 6/4479 - G02B 6/4498

The following arrangement is observed for the coupling aspects of the various types of light guides:

Coupling light guides for illumination

G02B 6/0001 - G02B 6/0096

Coupling of optical fibres

G02B 6/24 - G02B 6/43

Coupling waveguides of the integrated circuit kind

G02B 6/12 - G02B 6/14, G02B 6/26, G02B 6/30, G02B 6/34, G02B 6/3596, G02B 6/42, G02B 6/43

Coupling subwavelength diameter waveguides

G02B 6/107

Coupling of other waveguides

G02B 6/10, G02B 6/26, G02B 6/34, G02B 6/4298

Coupling, installation and handling of optical cables

G02B 6/4439 - G02B 6/4478, G02B 6/4495, G02B 6/4497, G02B 6/46 - G02B 6/54

Storage of optical fibres

G02B 6/4439

Polarisation aspects

The following arrangement is observed in relation to polarisation aspects of light guides and light guide couplings

Polarisation maintaining optical fibres

G02B 6/024

Polarisation issues within light guides per se, including optical fibres and planar waveguides (not polarisation maintaining optical fibres)

G02B 6/105

Polarisation manipulation by planar waveguide coupling

G02B 6/126

Polarisation manipulation by optical fibre coupling

G02B 6/27 - G02B 6/2793

Polarisation manipulating elements between light guides and optoelectronic elements

G02B 6/4215, G02B 6/4246

Wavelength selective aspects

The following arrangement is observed in relation to wavelength aspects of light guides and light guide couplings

Wavelength affecting properties of optical fibres (e.g. performance and mounting of single gratings or filters in optical fibre, dispersion tailoring)

G02B 6/02 - G02B 6/03694, especially G02B 6/02052 - G02B 6/02209 and G02B 6/02214 - G02B 6/02285

Wavelength selective elements (e.g. gratings, filters) in planar waveguides

G02B 6/122 - G02B 6/138, especially G02B 6/124, and G02B 6/12007 - G02B 6/12033

Coupling of planar waveguides for wavelength selection

G02B 6/12007 - G02B 6/12033

Coupling of optical fibres for wavelength selection

G02B 6/293 - G02B 6/29398

Wavelength selective elements between light guides and optoelectronic elements

G02B 6/4215, G02B 6/4246

Indexing Codes are used in some subgroups related particularly to coupling aspects to indicate additional details not available for the particular type of light guide, for example G02B 6/293 - G02B 6/29398 are assigned to waveguides of the integrated circuit kind with wavelength selective elements in addition to G02B 6/12007.

The Indexing Codes corresponding to G02B 6/0001 - G02B 6/001 and G02B 6/0096 are in F21V 2200/00.

Indexing Codes with additional detail compared to the subgroups exist in various parts of G02B 6/00, including G02B 6/032, G02B 6/02123, G02B 6/2804, G02B 6/36, G02B 6/4292 and G02B 6/4296.

G02B 2006/0098 is assigned to light guides for scanning in addition to the appropriate invention group which depends on the type of light guide.

An Indexing Code is occasionally given as a tag to the implementation of light guides in optical systems which are not covered by G02B 6/00 for assisting awareness of the existence of the related subclasses.

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Planar waveguides

waveguides of the integrated circuit kind

{specially adapted for lighting devices or systems (lighting or signalling on vehicles using light guides B60Q 1/00; lighting devices for vehicle dashboards B60Q 3/10; lighting devices for vehicle interior using light guides B60Q 3/62; lighting devices mounted on the vehicle rear part using light guides F21S 43/235; measuring arrangements having light conducting pointers G01D 13/265; illumination of liquid crystal displays G02F 1/1336; illuminated signs G09F 13/00)}
Definition statement

This place covers:

Aspects of the light guides for illumination per se as well as light coupling aspects.

Further details of subgroups

Illustrative example of the subject matter classified in this group:

media165.png

Grooves in the light input face of light guide 100. (Source US2004/0207775 A1).

Illustrative example of the subject matter classified in this group:

media166.png

Redirecting reflective surfaces 13. (Source EP1113218 A1).

Illustrative example of the subject matter classified in this group:

media167.png

Input face 2 shaped as a lens surface. (Source WO 2004/104476).

Illustrative example of the subject matter classified in this group:

media168.png

Recesses 9 in the light guide housing the light sources 8. (Source EP1666936 A1).

Illustrative example of the subject matter classified in this group:

media169.png

Prismatic sheets 56a, 56b between light source 52 and light guide 34. (Source US2003/0117793 A1).

Illustrative example of the subject matter classified in this group:

media172.png

Interference reflector 30 as wavelength selective element between light source 20 and light guide 12. (Source US2006/0002678 A1).

Illustrative example of the subject matter classified in this group:

media174.png Intermediate light guides (optical fibers 121, 122, 123) for coupling into light guide plate 13. (source US2006/0007702 A1). media175.png

Intermediate light guide rod 2 with sideways coupling into light guide 1. (Source EP 1139015 A1).

Illustrative example of the subject matter classified in this group:

media176.png

Intermediate lens 105, also used for lens sheets. (Source EP 1574780 A1)

Illustrative example of the subject matter classified in this group:

media177.png

Reflector 5. (Source WO2004/109380).

Illustrative example of the subject matter classified in this group:

media178.pngmedia179.png

Protrusions 20 arranged in a 2D-array (applied for both regular and irregular arrays). (Source US2003/0156403 A1).

Illustrative example of the subject matter classified in this group:

media180.pngmedia181.png

Grooves 11. (Source EP 939273 A1)

Illustrative example of the subject matter classified in this group:

media182.pngmedia183.png

Scattering particles 29, 30 in the bulk. (Source WO2005/024478).

Illustrative example of the subject matter classified in this group:

media185.png

Scattering dots 31 on the surface of the light guide 20. (Source US 2004/0228109 A1).

Illustrative example of the subject matter classified in this group:

media187.png

Variation of the thickness of light guide plates. (Source WO2005/080863).

Illustrative example of the subject matter classified in this group:

media188.png

Stepped variation of the thickness of light guide plates. (source US2005/0248959 A1).

The mere indication that a diffusion film, a prism film or a reflecting film is present does not justify classifying in G02B 6/005 and its subclasses. At least some details of these elements have to be given in the document.

Illustrative example of the subject matter classified in this group:

media305.png

media189.pngDiffusion film 14. (Source EP 1677047 A1).

Illustrative example of the subject matter classified in this group:

media190.pngmedia191.png

Prism film 11. (Source WO2005/026793).

Illustrative example of the subject matter classified in this group:

media304.png

Reflection sheet 5. (Source US 6,486,931 B1).

Illustrative example of the subject matter classified in this group:

media193.png (Source EP 0597261 A1).

Illustrative example of the subject matter classified in this group:

media195.png

Variations purposely generating inhomogeneous light output, e.g. to display indicia or text. (Source US 5,846,070).

Illustrative example of the subject matter classified in this group:

media196.png

Variations (dot size) to compensate non-uniformities of light propagating in the light guide, so as to achieve homogeneous output intensity. (Source US2004/0136173 A1).

Illustrative example of the subject matter classified in this group:

media198.png Light exits through top and bottom surfaces. (Source DE102004038344 A1).

Manufacturing and material aspects of light guides having one of the features classified in G02B 6/0033 and G02B 6/0013 and lower.

Note: when classifying in this group, classification must also be made in one or more of the groups of G02B 6/0013 or G02B 6/0033 for the related device aspects

Illustrative example of the subject matter classified in this group:

media200.png

The invention relates to the manufacturing apparatus for surface light source apparatus 10 and includes a pattern design system for designing the light guide pattern portions 15. (Source US 2003/0210539 A1).

Illustrative example of the subject matter classified in this group:

media203.png

Plural light sources 22. (Source US 2006/0245210 A1).

Illustrative example of the subject matter classified in this group:

media205.png

Lamp 11. (Source GB 2180051 A).

Illustrative example of the subject matter classified in this group:

media208.png

Lamp tubes 212 and 222. (Source US 2003/0198038 A1).

The mere indication that an LED is used does not justify classifying in this group.

Illustrative example of the subject matter classified in this group:

media209.png Translucent concave end face 3a has the same curvature as a translucent convex face 6 of the LED lamp 2 (Source EP 1434277 A1).

Illustrative example of the subject matter classified in this group:

media211.png

Stacked light guide plates 11 and 13. (Source US 2006/0164862 A1).

Illustrative example of the subject matter classified in this group:

media212.png

(Source DE 102004046256).

Illustrative example of the subject matter classified in this group:

media306.png

Sections 7b and 7c of adjacent light guides overlap. (Source EP 2241800 A1).

Illustrative example of the subject matter classified in this group:

media215.png

Chips 62, Wiring elements 66. (Source US 2010/0246209 A1).

Illustrative example of the subject matter classified in this group:

media217.png

Heat sink 224. (Source US2010/0027293 A1).

Illustrative example of the subject matter classified in this group:

media219.png

Fixing projections 110, 210 in the housing and support grooves 130, 230 in the light guide for fixing the light guide in the housing. (Source EP 2259104 A2).

Illustrative example of the subject matter classified in this group:

media220.png

Guiding structure 300 and securing device 202 for fixing the light source in the housing. (Source US2009/0290381 A1).

Illustrative example of the subject matter classified in this group:

media221.png

This group is used for devices holding the light source(s) and being directly attached to the light guide, like clamp 8 containing light emitter 9 and being attached to light guide plate 1. (Source US 2007/0285944 A1).

Illustrative example of the subject matter classified in this group:

media224.png

Protective cover 28. (Source EP 1283391 A2).

Illustrative example of the subject matter classified in this group:

media225.png

Shelves 32 formed as light guide panels. (Source US 2004/0264161 A1).

media226.png

Bath tub with light guide 11 and light source 16. (Source WO 02/100230).

Relationships with other classification places

G02B 6/0001 and subgroups include backlights comprising light guides for liquid crystal display panels. Other aspects (other than the light guide) of liquid crystal display backlights are classified in G02F 1/1336. Direct backlights not including a light guide are classified in G02F 1/133602

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Lighting or signalling on vehicles using light guides

B60Q 1/00

Lighting devices for vehicle dashboards

B60Q 3/10

Lighting devices for vehicle interior using light guides

B60Q 3/62

Lighting devices mounted on the vehicle rear part using light guides

F21S 43/235

Measuring arrangements having light conducting pointers

G01D 13/265

Illumination of liquid crystal displays

G02F 1/1336

Illuminated signs

G09F 13/00

Special rules of classification

Light guides in the form of long rods for illumination are classified in G02B 6/0005 and subgroups. The Indexing Codes corresponding to G02B 6/0001 - G02B 6/001 and G02B 6/0096 are in F21V 2200/00.

Optical fibre with cladding {with or without a coating} (mechanical structures for providing tensile strength and external protection G02B 6/44)
Definition statement

This place covers:

Optical and mechanical properties of optical fibres per se as well as optical fibres with an integral optical element, such as a Bragg grating.

Further details of subgroups

What is considered large or small usually depends on the type of fibre. For example an area of 50 square microns can be considered large for a dispersion compensating fibre (then G02B 6/02009 and G02B 6/02261 should be given) but not large for a non-zero dispersion shifted fibre (i.e. not classified in G02B 6/02004).

Graded multimode plastic optical fibres are classified in G02B 6/02038 not G02B 6/0288. Fibres compensating modal dispersion are usually classified in G02B 6/0288 or G02B 6/02038 as they typically involve a graded index multimode fibre. 1 mm core graded POF is classified in G02B 6/02038.

G02B 6/02214 is for dispersion tailoring only at wavelengths other than around the 1550nm window (e.g. for 850 nm, 1300 nm). G02B 6/02223 is for dispersion tailoring at 1550nm and another wavelength, e.g. 1300 nm, in the same optical fibre.

Illustrative example of the subject matter classified in this group:

media303.png

Illustrative example of the subject matter classified in this group:

media228.png (Source WO9942869).

Illustrative example of the subject matter classified in this group:

media229.png (Source WO9733188).

Illustrative example of the subject matter classified in this group:

media230.png (Source WO9942869).

Graded multimode plastic optical fibres are classified in G02B 6/02038 not G02B 6/0288. Fibres compensating modal dispersion are usually classified in G02B 6/0288 or G02B 6/02038 as they typically involve a graded index multimode fibre. 1 mm core graded POF is classified in G02B 6/02038.

Illustrative example of the subject matter classified in this group:

media231.png (Source WO03012489).

media232.png (Source WO02088041).

With reference to the notes to G02B 6/03616, graded inner clad 2 is not considered a layer in the sense of G02B 6/03616. Hence these examples are not for G02B 6/03633.

Some documents define the central core as the segment from the centre to where the refractive index delta is zero (e.g. US6421490 defines "the radius from the waveguide centerline to the location of the last refractive index point is the outer radius of the core segment."). The definition in the G02B 6/03616 notes takes precedence.

The outer cladding is also considered a layer. If the coating affects the guiding due to its refractive index then it is also considered a cladding layer. Care must be taken not to count beyond the external clad e.g. the following example has 2 clad layers, the top figure can be misleading.

media233.png

(Source EP1439408).

When the profile shows many alternating refractive index layers possibly G02B 6/023 will be relevant.

Illustrative example of the subject matter classified in this group:

media234.png

Radial asymmetry concept not reflected in lower subgroups. (Source WO2004023182).

Illustrative example of the subject matter classified in this group:

media235.png

(Source US2005089289).

Illustrative example of the subject matter classified in this group:

media236.png (Source EP1158323).

G02B 6/03611 as additional information is used for some documents where the profile has a centreline depression as a result of the manufacturing procedure but there is no purposeful effect on the guiding properties or dispersion properties.

media237.png (Source US2006045449).

This is however not classified in G02B 6/03611 Since the centreline dip does not affect the optical fibre properties and it is not discussed in the document in detail.

Illustrative example of the subject matter classified in this group:

e.g. W profile

media238.png Layers 2 (- relative to central core of width a) and 7 (+ relative to 2). (Source US2007009218).

Illustrative example of the subject matter classified in this group:

media239.png

Two layers 2 and 5 around central core segment 1. Layer 2 is a layer in the sense of the G02B 6/03616 definitions, and thus G02B 6/0285 is not appropriate. (Source EP1189082).

media240.png

Central core segment between -a and a, first layer (ring) between a and b, second layer (ring) between b and d. (Source EP856754).

Illustrative example of the subject matter classified in this group:

media241.png

(Source US2007116418).

Illustrative example of the subject matter classified in this group:

e.g. WT profile

media242.pngLayer 1 -, layer 2 +, layer 3 -. (Source: Li et al in Optical Engineering, Dec. 1994, Vol. 33, p. 3999 (XP484832)).

media243.png

Central core segment 41 (design), 60 (measurement) with three surrounding layers arranged - + -. (Source US5659649).

Illustrative example of the subject matter classified in this group:

media244.png- (21) - (22) + (23). (Source EP260795).

Illustrative example of the subject matter classified in this group:

media245.png (Source US5032001).

Illustrative example of the subject matter classified in this group:

media246.png(Source US2007009218).

Illustrative example of the subject matter classified in this group:

media247.png(Source WO9733188).

Illustrative example of the subject matter classified in this group:

media248.png(Source US2004067034).

Illustrative example of the subject matter classified in this group:

media249.png

- (74) + (76) + (78) - (79). (Source WO0017680).

Illustrative example of the subject matter classified in this group:

media250.png

EP260795: - (21) - (22) + (40) + (41). (Source EP260795).

Illustrative example of the subject matter classified in this group:

media251.png

74-80= 5 layers. (Source WO0017680).

media252.png

6 layers. (Source US2005013571).

Illustrative example of the subject matter classified in this group:

media253.png

Layers 122 and 123 have the same refractive index but different loss properties. (Source EP0260795).

media254.pngmedia255.png

The Ge and Ge+Al l have the same refractive index but different acoustic properties. (Source US2007116416).

media256.png Layers 15 and 16 have the same refractive index but are formed by different methods so that layer 15 has lower losses but takes longer to form. (Source US2007204657).

Indexing Codes

Fluid core or claddings are classified in G02B 6/032 and G02B 2006/0325. No corresponding group exists for Indexing Code G02B 2006/0325.

References
Limiting references

This place does not cover:

Mechanical structures for providing tensile strength and external protection

G02B 6/44

Informative references

Attention is drawn to the following places, which may be of interest for search:

Optical fibres for infra-red or ultra-violet radiation

G02B 6/102

Optical fibres having polarisation effects except for polarisation maintaining optical fibres

G02B 6/105

Special rules of classification

All embodiments of patent documents are classified. This is of particular relevance for classifying multilayered optical fibre refractive index profiles in G02B 6/036 - G02B 6/03694.

of the optical waveguide type (G02B 6/02, G02B 6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F 1/00; transferring the modulation of modulated light G02F 2/00; optical logic elements G02F 3/00; optical analogue/digital converters G02F 7/00; stores using opto-electronic devices G11C 11/42; electric waveguides H01P; transmission of information by optical means H04B 10/00; multiplex systems H04J 14/00)
References
Limiting references

This place does not cover:

Optical fibres except for infra-red and ultraviolet transmitting optical fibres and optical fibres having polarisation effects

G02B 6/02

Optical fibre coupling, and coupling of light guides which are neither of the integrated circuit kind nor for illumination.

G02B 6/24

Devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means

G02F 1/00

Transferring the modulation of modulated light

G02F 2/00

Optical logic elements

G02F 3/00

Optical analogue/digital converters

G02F 7/00

Stores using opto-electronic devices

G11C 11/42

Electric waveguides

H01P

Transmission of information by optical means

H04B 10/00

Multiplex systems

H04J 14/00

Informative references

Attention is drawn to the following places, which may be of interest for search:

Light guides for illumination

G02B 6/0001

Polarisation maintaining optical

G02B 6/024

Probes and tips for near field optical microscopy

G01Q 60/18

Stores using electro-optical elements

G11C 13/047

Special rules of classification

Waveguides which are not of the integrated circuit kind, are not optical fibres and are not used for illumination are classified in the subgroups G02B 6/10 - G02B 6/107. There are three exceptions: the subgroups G02B 6/102 and G02B 6/105 include both optical fibres and waveguides of the integrated circuit kind, and G02B 6/107 includes all sub-wavelength diameter waveguides.

of the integrated circuit kind (production or processing of single crystals C30B; electric integrated circuits H01L 27/00)
Definition statement

This place covers:

Light guiding paths in an integrated circuit, particularly waveguides formed in a planar substrate, including single paths as well as multiple paths which interact with each other with or without optical elements in or between the light guiding paths. This subgroup further covers methods of producing the waveguides.

References
Limiting references

This place does not cover:

Production or processing of single crystals

C30B

Electric integrated circuits

H01L 27/00

Informative references

Attention is drawn to the following places, which may be of interest for search:

Photonic crystals not for waveguiding

G02B 1/005

Surface plasmon devices not for light guiding

G02B 5/008

Planar waveguides for infra-red or ultra-violet radiation

G02B 6/102

Planar waveguide paths having polarisation effects

G02B 6/105

Sub-wavelength diameter waveguides

G02B 6/107

Coupling fibres and integrated optical circuits

G02B 6/30

Optical analysis of materials by means of surface plasmons

G01N 21/553

Semiconductor devices sensitive to light

H01L 31/00

Semiconductor devices for light emission

H01L 33/00

Special rules of classification

Wavelength selective arrangements are classified in G02B 6/12007 with the corresponding Indexing Code symbols G02B 6/293 - G02B 6/29398 assigned. For example a planar waveguide arrangement of ring resonators for wavelength selection is classified in G02B 6/12007 and G02B 6/29338.

The coupling of light within planar waveguide substrates is classified in G02B 6/12 and subgroups. Coupling light into or out of an integrated circuit having light guiding paths is classified in the appropriate one of G02B 6/26, G02B 6/30 - G02B 6/305, G02B 6/34, G02B 6/3596, G02B 6/42 and G02B 6/43.

Indexing Codes

G02B 2006/12085 - G02B 2006/12092, G02B 2006/12111 and G02B 2006/12035 are inactive, i.e. they contain some documents but are not used for classification of new documents.

Some of the remaining Indexing Codes correspond to groups as shown in the table below.

The Indexing Codes G02B 2006/12095 - G02B 2006/12104, G02B 2006/12109, G02B 2006/12114 - G02B 2006/12128, G02B 2006/12135 - G02B 2006/12161, G02B 2006/12169, G02B 2006/12173, G02B 2006/12192 and G02B 2006/12197 are used for additional details not listed in the G02B 6/12 subgroups, for example a bent planar waveguide is classified in group G02B 6/125 and with Indexing Code G02B 2006/12119.

The status of the use of the Indexing Codes G02B 2006/12083 - G02B 2006/12197 is shown in the table below:

Coupling light guides (for electric waveguides H01P 1/00)
References
Limiting references

This place does not cover:

Electric waveguides

H01P 1/00

Informative references

Attention is drawn to the following places, which may be of interest for search:

Coupling of light guides of the planar or plate like form for lighting devices or systems

G02B 6/0011

Special rules of classification

Mechanical coupling aspects of optical elements other than the light guides is classified in the subgroup relating to the optical coupling. For example the mechanical coupling of a fixed reflective bulk diffraction grating between optical fibres is classified in G02B 6/2931, and mechanical means for holding a lens between an optical fibre and an opto-electronic element are classified in G02B 6/4204.

The mechanical coupling of light guides is classified in G02B 6/36-G02B 6/406 and/or G02B 6/42-G02B 6/43. When the mechanical coupling is for a particular type of optical coupling between light guides then the appropriate one of G02B 6/26-G02B 6/3596 is also given. For example a lens coupling together light guides which are mechanically coupled on a substrate is classified in G02B 6/36 - G02B 6/3696 and G02B 6/32.

{using thermal methods, e.g. fusion welding by arc discharge, laser beam, plasma torch}
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Making optical fibres with heat application

C03B 37/15

Optical coupling means (G02B 6/36, G02B 6/42 take precedence)
Definition statement

This place covers:

The optical coupling of light into, out of or between light guides.

Further details of subgroups

Illustrative example of the subject matter classified in this group:

media257.png

(Source US6208442).

NOTE US6804057 not for G02B 6/29302 as wavelength selection based on etalons not wavelength dependent polarisation effect

See additional explanation in the special rules section for more details relating to separation between G02B 6/29305 and G02B 6/29316 (concerning diffractive elements attached to optical fibres)

Free space means not confined, not necessarily that there is no material

media258.png

Bulk grating 25. (Source WO0137021).

Illustrative example of the subject matter classified in this group:

media259.png

Transparent block formed of 26', 28 and 22. (Source WO9931532).

Illustrative example of the subject matter classified in this group:

media260.png

Curved bulk grating 47. (Sources US2002181856 for fig. 11, US4784935 for fig.8).

Illustrative example of the subject matter classified in this group:

media261.png

(Source WO0137021).

Illustrative example of the subject matter classified in this group:

media262.png

Transmissive grating 9. (Source WO0029888).

Illustrative example of the subject matter classified in this group:

media263.png

Adjustable support 14 for positioning optical fibres 5 to 8. (Source US5305402).

Illustrative example of the subject matter classified in this group:

media264.png

Screw 17 for moving grating 9. (Source US4763969).

includes gratings in contact with the light guide causing diffraction in the light guide, e.g. in contact with the side of a polished fibre (i.e. no free space, no intermediate element other than coupling medium, closely linked to diffractive elements integrated in the light guide) i.e. beam interacting with the diffractive element confined in at least one dimension transverse to propagation. EP1574883 fig. 1 has collimator between fibre and diffractive film thus is not for group G02B 6/29317 (Indexing Code G02B 6/29317 is appropriate). US4148556 fig. 3 is for group G02B 6/29322 as grating is butt coupled.

Illustrative example of the subject matter classified in this group:

media265.png

Optical fibre 71 with grating 72. (Source US6334014).

Illustrative example of the subject matter classified in this group:

media266.png

Cascade of optical fibre gratings 325. (Source EP1024378).

Illustrative example of the subject matter classified in this group:

media267.png

Directional router 18 (circulator) and optical fibre grating cascade 12, 14. (Source EP857988).

Illustrative example of the subject matter classified in this group:

media268.png

Tunable optical fibre gratings 104 to 109. (Source EP95385).

media269.png

Tunable Bragg gratings (indicated by electrodes). (Source US6097861).

Illustrative example of the subject matter classified in this group:

media270.png

Light coupled via grating 12 through bottom (lateral) surface of light guide 10. (Source US6016375).

Illustrative example of the subject matter classified in this group:

media271.png

Slab light guide 50. (Source WO9211517).

Illustrative example of the subject matter classified in this group:

media272.png

Curved grating 22 on plate light guide 20. (Source US4784935).

Illustrative example of the subject matter classified in this group:

media273.png

Evanescent coupling in tapered portion 3. (Source EP416537).

Illustrative example of the subject matter classified in this group:

media274.png

Grating 130 in evanescent coupling region. (Source US20020028040).

Emphasis is on evanescent coupling from a waveguide mode to a resonant mode of a closed loop resonator but see US4720160 fig. 1 where loop resonators are not used. NB in a Sagnac, light only circulates once before interfering thus G02B 6/29347

NOTE: see additional explanation in the special rules section below for more details relating to separation between G02B 6/29335 and G02B 6/29356 or G02B 6/29358 (evanescent and non-evanescent coupling of resonators)

Illustrative example of the subject matter classified in this group:

media275.png

Linear resonator between 5 and 8 coupled via evanescent coupling at region 6. (Source US4859017).

Illustrative example of the subject matter classified in this group:

media276.png

Ring resonator 1404. (Source US6718086).

Illustrative example of the subject matter classified in this group:

media277.png

Evanescent coupling to a loop cavity 14a. (Source US4720160).

Whispering gallery mode (WGM) resonance corresponds to light that is trapped in circular orbits just within the surface of the structure. The modes are most strongly coupled along the equatorial plane and they can be thought to propagate along a zig-zag paths around the sphere.

media278.pngmedia279.png

Microsphere 120 supports WGM resonance. (Source US6389197).

media280.png

(Source US2005128566).

Illustrative example of the subject matter classified in this group:

media281.png

Cascade of loop resonators 1004, 1008, 1016, 1018,1020, 1022. (Source US6643421).

media282.pngmedia283.png

At wavelength L1 shown in FIG. 1a, the dual-mode section W2 is n beatlengths long and the filter (fig. 5) passes radiation. At wavelength L2 shown in FIG. 1b, the dual-mode W2 section is n-1/2 beatlengths long and so radiation is not coupled from the dual-mode filter to the output single-mode filter (W3). (Source US5796891).

Emphasis is on interference between split beams at least one of which travels a loop delay distance

media284.png

Loops 27 and 37 apply two different delays to beams along optical paths, so that the beams are interfered to form respective output beams corresponding to odd and even communication channels. (Source US2003234935).

Illustrative example of the subject matter classified in this group:

US6252716

media285.png

(Source US6252716).

Illustrative example of the subject matter classified in this group:

media286.png

(Source EP1293814).

Illustrative example of the subject matter classified in this group:

media287.png

Ring resonator 310 coupled to arm 322 of Mach-Zehnder Interferometer. (Source US6834141).

media288.png

Gratings 212 & 214 in arms 208 & 201 of Mach-Zehnder Interferometer. (Source US2006002653).

Illustrative example of the subject matter classified in this group:

media289.png

Cascade of Mach-Zehnder Interferometers 13a-13d. (Source WO2005071453).

Illustrative example of the subject matter classified in this group:

media290.png

End coupling into cavities formed by reflective gratings 209, 210. (Source EP1024378).

NOTE: see additional explanation in the special rules section for more details relating to separation between G02B 6/29335 and G02B 6/29356 or G02B 6/29358 (evanescent and non-evanescent coupling of resonators)

media291.png

Interferometer 1. (Source EP1703307).

NOTE: see additional explanation in the special rules section for more details relating to separation between G02B 6/29335 and G02B 6/29356 or G02B 6/29358 (evanescent and non-evanescent coupling of resonators)

Cavity outside light guide, does not include intermediate elements between fibre end face and filter.

media292.png

Cavity 26 between mirrors 30 & 32 on ends of light guides 38 & 40. (Source US5202939).

Illustrative example of the subject matter classified in this group:

media293.png

Cascade of filters 131, 132, 133. (Source US2008112668).

media294.png

Cascade of filters 73 & 75. (Source WO2006080249).

Illustrative example of the subject matter classified in this group:

media295.png

Cascade of filtering operations on single filter 24 by light guide 12. (Source WO03021319).

Illustrative example of the subject matter classified in this group:

media296.png

Zigzag path between filter film 7 and reflector film 8. (Source GB2304204).

Illustrative example of the subject matter classified in this group:

media297.png

Zigzag path in solid block formed of components 74,78,81 and single solid block 2 (Sources WO2006080249 for fig. 30, GB2304204 for fig. 1).

No coupling optics (such as a lens) between fibre and filter

media298.png (Source Yokosuka et al. Proc. 40th Electronic components and technology conference, May 20-23, 1990, p. 865, XP144764).

Illustrative example of the subject matter classified in this group:

media299.png

(Source US2004042719)

media300.png

(Source US2003025967)

Illustrative example of the subject matter classified in this group:

media301.png

Dispersive prism 3. (Source JP55057804).

Illustrative example of the subject matter classified in this group:

media302.png

Light guides 103, 105, 107 and 109 with different dispersion. (Source EP0684709).

Illustrative example of the subject matter classified in this group:

media140.png

Input signal A demultiplexed into different wavelength signals. (Source US6643421).

Illustrative example of the subject matter classified in this group:

media141.png

Signal added at F-A and dropped at F-D. (Source US6718086).

Illustrative example of the subject matter classified in this group:

media142.png

Input signal 1610 de-interleaved into odd and even channels 1620, 1630. (Source EP1293814).

References
Limiting references

This place does not cover:

Mechanical coupling means

G02B 6/36

Coupling light guides with optoelectronic elements

G02B 6/42

Informative references

Attention is drawn to the following places, which may be of interest for search:

Coupling of light within planar waveguide substrates of the integrated circuit kind

G02B 6/12

Scanning using movable fibres

G02B 26/103

Systems for wavelength dispersion compensation

H04B 10/2513

Systems for polarisation mode dispersion compensation

H04B 10/2569

Systems for wavelength division multiplexing

H04J 14/02

Optical switching systems

H04Q 11/0001

Special rules of classification

G02B 6/287 is not used for classification. G02B 6/255, G02B 6/2835, G02B 6/2856 and G02B 6/29331 are used instead.

The following arrangement is observed in relation to optical fibre couplers:

Optical fibre couplers of the NxN type (e.g. 2x2)

G02B 6/2821

Optical fibre couplers of the 1xN type formed by thermal treatment

G02B 6/2856

Prisms or gratings coupled to light guides for purposes other than wavelength selection are classified in G02B 6/34.

Systems for wavelength division multiplexing based on optical fibres are classified in H04J 14/02. Reference is made to the section "Relationship between large subject-matter areas" under G02B 6/00.

Planar waveguides

Couplings between separate planar waveguide substrates, e.g. using intermediate bulk optics, are classified in G02B 6/26. Planar waveguide couplings are also classified in G02B 6/30-G02B 6/305, G02B 6/34, G02B 6/3596, G02B 6/42 and G02B 6/43.

G02B 6/262-G02B 6/29398, G02B 6/32-G02B 6/327 are restricted to light guides of the optical fibre type.

The coupling of light within planar waveguide substrates is classified in G02B 6/12 and subgroups. For example optical fibre couplers are classified in G02B 6/2804 whereas planar waveguide couplers are classified in G02B 6/125. The one exception is G02B 6/3596.

In G02B 6/35 and subgroups a single subgroup is assigned (the most relevant) with further aspects classified in the Indexing Code.

Indexing Codes

No groups correspond to Indexing Codes G02B 2006/2839 and G02B 2006/2865.

Separation between G02B 6/29305 and G02B 6/29316

G02B 6/29305 is for bulk diffraction elements (gratings) with free space between the light guide and grating. This means that before interacting with the grating the light beams are not guided in the light guide for a certain distance (or vice-versa).

G02B 6/29316 is for light guides comprising the grating. This means there is no free space between the light guide and the grating and the light beams are guided in the light guide onto the grating (or vice-versa).

Examples.

media144.png

Diffractive film DF is on a collimator C. (Source EP1574883).

media145.png

Butt coupled grating 50, no free space to light guide 42. (Source US4148556).

media146.png

No free space between grating and fiber. (Source Sorin et al. in Journal of Lightwave Technology, Vol. LT-3, Oct 1985, p. 1041, XP1652325).

Separation between G02B 6/29346 and G02B 6/29335

Parallel plate resonators can be in either G02B 6/29358 or G02B 6/29335 - the correct group depends on how the resonator is coupled to the light guide.

Where light is coupled into the resonator from the light guide by evanescence G02B 6/29335 is appropriate (i.e. the evanescent field of the light guided in the light guide overlaps with the resonant mode of the resonator). This is usually the case with lateral coupling, but not always.

Examples

US20070104421 in G02B 6/29358

media147.png

Parallel plate resonators formed by resonator members 18, 19, 28 and 29 external to light guides 13, 23 and light coupled between resonators and light guides by deflector means 16 and 26. (Source US20070104421).

media148.png

Linear resonator between 5 and 8 coupled via evanescent coupling at region 6. (Source US4859017).

Devices of the type shown in fig. 1-3 below with evanescent coupling to a linear cavity between mirrors 24 & 26 are classified in G02B 6/29337, of the type shown in fig. 4 below with evanescent coupling to a loop cavity 14a are classified in G02B 6/2934

media149.png(Source US4720160).

Devices of the type shown in fig. 6B with evanescent coupling to a cascade of loop resonators 180 are classified in G02B 6/29343. Devices of the type shown in fig. 7A & 9C below with end coupling into cavities formed by reflective gratings (i.e. without evanescent coupling into a resonator cavity) are classified in G02B 6/29356.

media150.pngmedia151.png

(Source EP1024378).

Mechanical coupling means (G02B 6/255, G02B 6/42 take precedence)
Definition statement

This place covers:

The mechanical coupling of optical fibres, e.g. mechanical means for holding optical fibres on a substrate, and mechanical means such as connectors for the interconnection of optical fibres.

Further details of subgroups

Illustrative example of the subject matter classified in this group:

media152.png

(Source US2003/0179980).

Illustrative example of the subject matter classified in this group:

media153.png

(Source EP 1 182 483).

Illustrative example of the subject matter classified in this group:

media154.png

(Source US2006/0251374).

Illustrative example of the subject matter classified in this group:

media155.png

(Source US 4,799,755).

Illustrative example of the subject matter classified in this group:

media156.png

Optical fibre (16). (Source WO03/021312).

Illustrative example of the subject matter classified in this group:

media157.png

(Source US 2004/0086255).

Illustrative example of the subject matter classified in this group:

media158.png

(Source US2001/0042756).

Illustrative example of the subject matter classified in this group:

media159.png

(Source WO01/37005).

Illustrative example of the subject matter classified in this group:

media160.png

(Source US2004/0208422).

Illustrative example of the subject matter classified in this group:

media161.png

(Source US2003/0031436). (also classified in G02B 6/3676).

Illustrative example of the subject matter classified in this group:

media162.png

(Source US2003/0215206).

Illustrative example of the subject matter classified in this group:

media163.png

(Source WO03/007036).

Illustrative example of the subject matter classified in this group:

media164.png

(Source GB2331161).

References
Limiting references

This place does not cover:

Splicing of light guides by fusion or bonding

G02B 6/255

Coupling light guides with optoelectronic elements

G02B 6/42

Informative references

Attention is drawn to the following places, which may be of interest for search:

Light guides formed by bundle of fibres, the relative position of the fibres being the same at both ends, e.g. for transporting images

G02B 6/06

Optical coupling means for use between fibre and thin-film device

G02B 6/30

Optical coupling means having switching means

G02B 6/35

Optical coupling means having fibre to fibre mating means

G02B 6/38

Cleaning of optical fibres and connectors

B08B 1/00

Special rules of classification

The mechanical coupling between optical fibres or of optical fibres with opto-electronic elements is classified in the appropriate groups of G02B 6/38 - G02B 6/3897 and G02B 6/42-G02B 6/43 and additionally in Indexing Codes G02B 6/3608-G02B 6/3696, especially when the latter are more detailed. Light guides coupled together as a splice by mechanical holding means, i.e. mechanical splices, are classified in G02B 6/3801.

The mechanical coupling of optical fibre cables and the storage of optical fibres is classified in G02B 6/4401 and subgroups.

In G02B 6/3608-G02B 6/3696 as far as possible only one subgroup is assigned with further aspects classified in Indexing Codes G02B 6/3608-G02B 6/3696.

A demountable optical fibre connector is often classified in several of the G02B 6/3807 - G02B 6/3897 subgroups and/or Indexing Codes G02B 6/3807-G02B 6/3897 to reflect the various aspects of the connector. This is especially important to allow retrieval of mechanical configurations which are not easily searchable using words.

Optical fibre connector accessories and tools, e.g. for assembling, insertion or extraction of connectors not provided for elsewhere are classified in G02B 6/3807. The testing of optical fibre connectors is classified in G01M 11/00 and subgroups. Devices for cleaning optical fibre connectors are classified in G02B 6/3807 and circulated to B08B 1/00.

G02B 6/40-G02B 6/403 relate to optical fibre bundles in the sense of G02B 6/04.

Planar Waveguides

The mechanical coupling of planar waveguides is classified in the appropriate one of G02B 6/12-G02B 6/12033, G02B 6/30-G02B 6/305, G02B 6/42 and G02B 6/43.

{Permanent connections, i.e. wherein fibres are kept aligned by mechanical means (splices by bonding G02B 6/255; fusion splices G02B 6/2551)}
References
Limiting references

This place does not cover:

Splices by bonding optical fibres together

G02B 6/255

Fusion splices

G02B 6/2551

{without a ferrule embedding the fibre end, i.e. with bare fibre end}
Definition statement

This place covers:

Demountable optical fibre connectors presenting a protuding free optical fibre end

Illustrative example of subject matter classified in this group:

media307.png

(Sources: US5,694,506, FR2818839)

{of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres}
Definition statement

This place covers:

Demountable optical fibre connectors having ferrules.

Illustrative example of subject-matter classified in this group:

media308.png

Ferrules 11a, 11b. (Source: JPS5674211)

{Details of mounting fibres in ferrules; Assembly methods; Manufacture}
Definition statement

This place covers:

Details of the ferrule, mounting of prepared optical fibre in the ferrule.

{Mounting ferrules to connector body, i.e. plugs}
Definition statement

This place covers:

Mounting of the assembled fibre and ferrule into the connector body and details of the connector body.

Coupling light guides with opto-electronic elements
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Beam shaping of a semiconductor light source

G02B 27/0916

Beam shaping using a light guide

G02B 27/0994

High frequency adaptations of semiconductor devices

H01L 23/66

Semiconductor devices sensitive to light per se

H01L 31/00

Semiconductor devices for light emission per se

H01L 33/00

Semiconductor light sources with optical field shaping elements

H01L 33/58

Electrical conduction aspects of semiconductor light sources

H01L 33/62

Arrangements for extracting light from an organic light source

H01L 51/5262

Optical interconnects

H04B 10/801

Printed circuit boards

H05K 1/18

Cooling, ventilating or heating electrical apparatus

H05K 7/20

Special rules of classification

Optical coupling aspects of light guides for illumination are classified in G02B 6/0001 - G02B 6/0096. The coupling of non coherent light, including lamps, into optical fibres for purposes other than illumination is classified in G02B 6/4298.

Electric, thermal and mechanical aspects of packages not covered by G02B 6/4202 - G02B 6/4298 are classified in G02B 6/4201. G02B 6/4201 - G02B 6/4215 also include documents where the light guide is implicit.

The coupling of light guides with opto-electronic elements using a wavelength selective or polarisation selective and adjusting optical element are classified in G02B 6/4215 or G02B 6/4246 and the relevant G02B 6/27 - G02B 6/2793 and/or G02B 6/293 - G02B 6/29398, since the latter are more detailed.

Mechanical coupling aspects of optical fibre arrangements classified in G02B 6/42 - G02B 6/43 are additionally classified in G02B 6/36 - G02B 6/3696 especially when the latter are more detailed.

Connector aspects of disconnectable light guide arrangements classified in G02B 6/4292 are also classified in G02B 6/3807 - G02B 6/3897 and/or G02B 6/3807 - G02B 6/3897.

Planar Waveguides

Planar waveguides coupled with optoelectronic elements are classified in G02B 6/42 with G02B 6/4201 - G02B 6/4296 assigned for the details (e.g. G02B 6/42 and G02B 6/4214), however monolithic configurations, i.e. where the planar waveguide and optoelectronic element are grown on the same substrate are classified in G02B 6/12004.

Indexing Codes

G02B 6/4292 has the additional Indexing Code G02B 2006/4297 for protection means, e.g. using shutters to avoid inadvertent exposure

Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables (cables incorporating electric conductors and optical fibres {where features relating to the optical fibres are not of interest} H01B 11/22)
References
Limiting references

This place does not cover:

Cables incorporating electric conductors and optical fibres (where features relating to the optical fibres are not of interest)

H01B 11/22

Special rules of classification

G02B 6/4439-G02B 6/4478 are also used for classifying auxiliary devices with uncabled optical fibres. For example the storage of optical fibres in spools is classified in G02B 6/4457.

Optical cable installations in buildings, for example over multiple floors, are classified in G02B 6/4466.

Indexing Codes

Processes or apparatus adapted for installing optical fibres or optical cables (installation of cables containing electric conductors and optical fibres H02G)
References
Limiting references

This place does not cover:

Installation of cables containing electric conductors and optical fibres

H02G

Special rules of classification

G02B 6/52 is not used, G02B 6/4464 and G02B 6/50-G02B 6/508 are used instead.

G02B 6/54 is not used, G02B 6/4465 and G02B 6/50 are used instead.

Indexing Codes

No Indexing Codes exist.

Mountings, adjusting means, or light-tight connections, for optical elements
Definition statement

This place covers:

Mountings, adjusting means, including means for effecting focusing and zooming, and light-tight connections for optical elements like lenses, prisms or mirrors or the like.

Special rules of classification

The following simplified arrangements are to be observed in relation to mechanical aspects of focusing and zooming (G02B 7/04):

  • Non-zoom systems: Manual focusing: G02B 7/04
  • Non-zoom systems: Automatic (motorized) focusing: G02B 7/08
  • Zoom systems: Manual focusing and zooming: G02B 7/10
  • Zoom systems: Automatic (motorized ) focusing and zooming: G02B 7/102
  • G02B 7/10 and G02B 7/102 relate to the mechanical aspects of zoom lenses (e.g. cam arrangements). The optical aspects of the design of zoom lenses are covered by G02B 15/00.

The following IPC subclasses are not used for classification: G02B 7/185 - G02B 7/198 (subject-matter covered by G02B 7/182 and other subgroups of G02B 7/182).

Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - (G02B 15/00 takes precedence)
Definition statement

This place covers:

Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -. The plus (+) symbol represents a positive lens, and the minus (-) symbol represents a negative lens

References
Limiting references

This place does not cover:

Optical objectives with means for varying the magnification

G02B 15/00

Optical objectives specially designed for the purposes specified below (with variable magnification {in general} G02B 15/00)
Definition statement

This place covers:

Optical objectives specially designed for specific purposes.

Further details of subgroups

Concerning the subgroup G02B 13/001 (miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras), symbols from G02B 13/0015 and G02B 13/0055 will usually be assigned. In G02B 13/002, one compound lens counts as one lens. The symbol G02B 13/006 indicates the presence of a compound element. The following figures illustrate typical examples of the subject-matter found in the indicated subdivisions:

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

With variable magnification in general

G02B 15/00

Special rules of classification

With the exception of G02B 13/06, optical objectives having reflecting surfaces are not classified under G02B 13/00, but under G02B 17/00.

Unless specified in the title of the subgroups, this group and its subgroups do not cover objectives comprising reflecting surfaces, which are covered by G02B 17/06, G02B 17/08 and their subgroups

{characterised by the lens design}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media1.jpg

{having at least one aspherical surface}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media2.jpg

(note: second group G02B 13/007)

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Aspherical lenses per se

G02B 3/02

{having one lens only}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media3.jpg

{having two lenses}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media4.jpg

{having three lenses}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media5.jpg

{having four lenses}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media6.jpg

{having five or more lenses}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:media7.jpg

{having spherical lenses only}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media8.jpg

{employing a special optical element}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media9.jpg

(as a tag, double classification with the group for the respective element)

{at least one element being a compound optical element, e.g. cemented elements}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media10.jpg

{having a beam-folding prism or mirror}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media11.jpg

{the beam folding prism having at least one curved surface}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media12.jpg

{having an element with variable optical properties}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media13.jpg(lenses 310 are deformed by exerting radial force on the lens bodies; other variable elements, diaphragm, LC-elements, etc.)

{designed for infrared light}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media14.jpg

{employing wafer level optics}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media15.jpg

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Lens arrays per se

G02B 3/0006

{having zoom function}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media16.jpgDetails covered by G02B 15/00 are to be classified there as well.

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Zoom lenses per se

G02B 15/00

Panoramic objectives; So-called "sky lenses" {including panoramic objectives having reflecting surfaces}
Definition statement

This place covers:

Objectives designed to cover a very wide field of view not achievable by standard lens systems.

For example:

  • Very wide objectives, e.g. fisheye lenses, were the increase in coverage is done at the expense of distortion correction
  • Reflecting optical systems
  • Multiple lens systems providing an extended field coverage
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

optical sysyems for splitting a field on multiple detectors

G02B 27/1066

Special rules of classification

G02B 13/06 is also used to classify catadioptric optical systems providing a 360°overage

Rectilinear,e.g. non-distorting, wide angle objective are classified in G02B 13/04

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Sky lens

Objective designed for full sky coverage, e.g. for an hemispheric field of view

Optical objectives with means for varying the magnification (anamorphotic objectives G02B 13/08)
Definition statement

This place covers:

Refractive optical objectives with means for varying the magnification, e.g. zoom lenses;

optical aspects thereof.

References
Limiting references

This place does not cover:

Anamorphotic objectives

G02B 13/08

Informative references

Attention is drawn to the following places, which may be of interest for search:

The mechanical aspects of zoom lenses (e.g. cam arrangements) are covered by

G02B 7/04

Simple miniaturized zoom lenses for mobile electronic devices

G02B 13/009

Catoptric systems having a variable magnification

G02B 17/0694

Catadioptric systems having a variable magnification

G02B 17/0896

Optical systems with movable elements for controlling the degree of correction of specific optical aberrations

G02B 27/0068

Special rules of classification

The range G02B 15/142 - G02B 15/1465 covers zoom objectives characterised by the number of groups and the corresponding refractive power sign sequence of the groups.

The refractive power of a group is the combined refractive power of the lenses constituting the group.

Groups are counted as consecutive sets of one or more lenses that remain fixed or move in unison, e.g., distances between lenses are constant within a group whereas distances between groups are variable during zooming.

Lens groups having two or more separate subgroups with a variable spacing are to be counted as multiple groups.

The symbols have the following systematic structure:

"A" is the number of groups

"B" defines the sign of the first group: 1 if the refractive power of the group is positive and 5 if negative

"CD" is a two-digit number with an eventual leading zero defining the remaining refractive power sequence on the basis of a decimal conversion of the plus (1) or minus (0) binary sequence of the positive groups, e.g. the sum of the values of the remaining positive groups, plus one (1):

media310.png

The first group has always the value of one (1) regardless of the sign of the first group, e.g. one (1) is added to the total, to avoid trailing zeros.

The sign of the first group is coded in position B.

Examples:

  • A four group zoom arranged - + + - ("0110")

A = 4 groups

B = 5 (1st negative)

CD = 1*1+2*1+4*1+8*0 = 07

G02B 15/144507 { arranged - + + - }

  • A five group zoom arranged + + + - + ("11101")

A = 5 groups

B = 1 (1st positive)

CD = 1*1+2*1+4*1+8*0+16*1 = 23

G02B 15/145123 { arranged + + + - + }

Synonyms and Keywords

In patent documents, the word/expression in the first column is often used instead of the word/expression in the second column, which is used in the classification scheme of this place:

Lens group

A consecutive set of one or more lenses that remain fixed or move in unison.

Systems with reflecting surfaces, with or without refracting elements (microscopes G02B 21/00; telescopes, periscopes G02B 23/00; for beam splitting or combining G02B 27/10; for optical projection G02B 27/18)
Definition statement

This place covers:

Systems with reflecting surfaces, with or without refracting elements, e.g. catoptric systems, catadioptric systems

G02B 17/00, as the main group, is only for reflecting systems which do not fit into any of the sub-groups.

Example: a polar to rectangular coordinates converter:

media17.png

References
Limiting references

This place does not cover:

Panoramic objectives

G02B 13/06

Reflective microscope objectives

G02B 21/04

Telescopes, periscopes

G02B 23/00

Scanning optics with mirrors

G02B 26/126

Beamsplitters or combiners

G02B 27/10

Devices for optical projection

G02B 27/18

Optical derotators, e.g. rotating dove prisms

G02B 27/642

Special rules of classification

G02B 17/00 in general should be seen as an optical design group.

The division with G02B 17/08 (catadioptric systems) is strict, the presence of any refracting element having power or asphere to correct the aberrations of the system qualifies the combination as catadioptric.

Solid systems (where the air is replaced by glass) are also catadioptric, even with zero power air interfaces.

Some application specific mirror systems relating to G02B are covered by groups outside this main group. However details might be classified in G02B 17/00. Examples are:

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Zero power surface

a flat reflective or refractive surface without optical power, i.e. having no converging or diverging effect on light

{Arrays of reflective systems}
Definition statement

This place covers:

Arrays of reflective systems. This is essentially to mirror systems what lens arrays are for lenses. The class can be combined with other G02B 17/02, G02B 17/04, G02B 17/06, G02B 17/08 classes describing the optical design.

media18.png

{Systems comprising a plurality of reflections between two or more surfaces, e.g. cells, resonators (multipass arrangements for optical cuvettes G01N 21/031; laser resonators H01S 3/05)}
Definition statement

This place covers:

Systems comprising multiple reflections between at least two reflecting surfaces, e.g. cells, resonators. This subgroup covers both catadioptric and catoptric systems, as the number of documents is too small to justify a division between G02B 17/06 and G02B 17/08.

media19.png

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Multipass "cuvettes" in spectrophotometers

G01N 21/031

Laser cavities

H01S 3/00

{Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses (Fresnel mirrors G02B 5/09, Fresnel lenses G02B 3/08)}
Definition statement

This place covers:

Systems in which the light is reflected on a plurality of parallel laminas (venetian blind lens, louvre mirror, TIR - total internal reflection lens). This subgroup covers both catadioptric and catoptric systems, as the number of documents is too small to justify a division between G02B 17/06 and G02B 17/08. Fresnel mirrors are in G02B 5/09.

media20.png

{Systems specially adapted to form image relays or chained systems}
Definition statement

This place covers:

Reflective systems specially adapted to form relays or chainable optical systems. Mainly unit magnification systems like Dyson optics or Offner relays.

media21.png

Catoptric systems, e.g. image erecting and reversing system
Definition statement

This place covers:

Sequences of flat reflective (zero power) surfaces made of mirrors and prisms.

media22.png

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Sequences of flat reflective (zero power) surfaces using prisms only

G02B 17/04

{for extending or folding an optical path, e.g. delay lines}
Definition statement

This place covers:

Essentially sequences of flat mirrors to extend a path length, e.g. in a flatbed scanner.

For extending an optical path length, e.g. delay lines

media23.png

{having static image erecting or reversing properties only (G02B 17/045 takes precedence; optical derotators G02B 27/642; optical devices for controlling the direction of light using movable or deformable optical elements G02B 26/08)}
Definition statement

This place covers:

Image erecting and reversing systems, beam redirecting.

Static systems for changing the direction of a beam or pivoting an image

media24.png

References
Limiting references

This place does not cover:

Prismatic systems with reflecting surfaces having static image erecting or reversing properties only

G02B 17/045

Movable reflecting elements for controlling the direction of light

G02B 26/08

optical derotators

G02B 27/642

using prisms only
Definition statement

This place covers:

Prism sequences as far as the reflecting surfaces have no power. Powered prisms generally go in the catadioptric class G02B 17/08 (unless an image erecting effect is produced).

media25.png

{having static image erecting or reversing properties only (optical derotators G02B 27/642; optical devices for controlling the direction of light using movable or deformable optical elements G02B 26/08)}
Definition statement

This place covers:

Image erecting and reversing systems, including classical erecting prisms. Similar to G02B 17/026, but with prisms only. Some overlap with G02B 5/04 and G02B 27/14.

media26.png

The class might also be given for solid catadioptric systems that integrate an erecting function.

media27.png

References
Limiting references

This place does not cover:

Movable or deformable reflecting elements for controlling the direction of light

G02B 26/08

Optical derotators

G02B 27/642

using mirrors only {, i.e. having only one curved mirror (used in non-imaging applications G02B 19/00)}
Definition statement

This place covers:

Systems comprising mirrors only.

combinations of a single curved mirror (on or off axis) with any number of plane mirrors go into the group G02B 17/06. Single segmented mirrors are classified in G02B 5/09. Synthetic aperture systems G02B 27/58)

media28.png

References
Limiting references

This place does not cover:

Mirror based non imaging systems

G02B 19/00

Special rules of classification

Further details of subgroups

The subgroups G02B 17/0605, G02B 17/0626 and G02B 17/0647 relate to systems having 2 mirrors, 3 mirrors and more than 3 mirrors respectively, and are strictly imaging groups, including linear field imaging systems (scanner optics).

The structure of these groups, by way of example for G02B 17/0605 is the following:

  • G02B 17/0605 On axis systems without a central aperture.
  • G02B 17/061 On axis systems, with at least one central aperture.
  • G02B 17/0615 Off-axis, unobscured, optical systems, the mirrors having a common optical axis.
  • G02B 17/0621 Off-axis or unobscured optical systems, the mirrors without a common optical axis, e.g. the mirrors have tilts and decenters. This includes also so-called free-form surfaces without rotational symmetry.

The general rule is to count the number of optical surfaces relevant for the optical design process:

  • An optical surface on which the beam is reflected twice counts as one mirror, however single mirror having multiple zones figured with different optical surfaces counts as two mirrors.
  • Simple flat folding mirrors are normally not counted when they are not essential to the invention, e.g. not relevant in the lens design process, for example a folding mirror.
  • Flat mirrors are counted when they are used to achieve a double reflexion on the same mirror, e.g. when a powered mirror surface is used twice. Flat reflecting surfaces in solid catadioptric systems count also.
  • When several systems are chained together, e.g. a telescope and a relay, the subsystems are counted and classified individually.
{using two curved mirrors (G02B 17/0668, G02B 17/0694 take precedence)}
Definition statement

This place covers:

On axis systems, without a central aperture.

media29.png

References
Limiting references

This place does not cover:

Having non-imaging properties

G02B 17/0668

With variable magnification or multiple imaging planes, including multispectral systems

G02B 17/0694

{on-axis systems with at least one of the mirrors having a central aperture}
Definition statement

This place covers:

On axis systems, with at least one central aperture.

media30.png

{off-axis or unobscured systems in wich all of the mirrors share a common axis of rotational symmetry}
Definition statement

This place covers:

Off-axis, unobscured, optical systems, the mirrors having a common optical axis.

media31.png

media32.png

{off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements}
Definition statement

This place covers:

  • Off-axis or unobscured optical systems, the mirrors without a common optical axis, e.g. the mirrors have tilts and decenters. This includes also so-called free-form surfaces without rotational symmetry.

media33.png

{using three curved mirrors (G02B 17/0668, G02B 17/0694 take precedence)}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

media34.png

References
Limiting references

This place does not cover:

Having non-imaging properties

G02B 17/0668

With variable magnification or multiple imaging planes, including multispectral systems

G02B 17/0694

{on-axis systems with at least one of the mirrors having a central aperture}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

mirror 2 is actually two mirrors 1 and 3.

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{off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{on-axis systems with at least one of the mirrors having a central aperture}
Definition statement

This place covers:

Illustrative examples of subject matter classified in this group:

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{off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{having non-imaging properties}
Definition statement

This place covers:

Non imaging systems.

Devices that are not emitter or receiver specific.

The group has been subdivided to cover systems disclosed as being used to illuminate a detector, or used in close conjunction with a light source (e.g. for LED illumination). Often the emitter/detector is an integral part of the device. Reflecting pipes are in G02B 27/0994 or G02B 6/00.

Example: a non-imaging system in the form of a rotating optical joint

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Special rules of classification

Further details of subgroups

G02B 17/0673 ..for light condensing (emitters)

G02B 17/0678 ... in a 360° plane or hemisphere

G02B 17/0684 ...for light collecting (receivers)

G02B 17/0689 ...in a 360° plane or hemisphere

{with variable magnification or multiple imaging planes, including multispectral systems (systems with only refractive elements G02B 15/14)}
Definition statement

This place covers:

Zoom mirror systems, but also multiple focus or multiple magnification systems, and systems having both large and small FOVs.

Catadioptric systems {(used in non-imaging applications G02B 19/00)}
Definition statement

This place covers:

Catadioptric systems

This group is subdivided according to the same scheme as the systems of G02B 17/06.

In addition, subgroups have been added to cover the structure or function of the refractive element.

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Special rules of classification

Further details of subgroups

G02B 17/0852: Field Corrector

Systems where a set of field lenses correct the aberrations of the mirrors.

The field corrector definition should be taken broadly to include systems where all lenses are located between the focal plane and the first mirror (starting from the FP).

Systems with field flattener lenses and pupil correctors get also this class when the design of the field corrector is detailed or discussed.

G02B 17/0884: Pupil Corrector

The pupil corrector having spherical surfaces, e.g. Maksutov or Houghton telescopes

G02B 17/0888: Pupil Corrector

The pupil corrector having an aspheric surface, e.g. Schmidt camera

G02B 17/0856 : Mangin mirror, i.e. a lens with a mirrored surface

G02B 17/086: Solid Catadioptric, e.g. comprising solid blocks

G02B 17/0864: Non imaging catadioptric

The G02B 17/0864 subgroup is subdivided according to the same scheme as the systems of G02B 17/0668.

G02B 17/0892: Specially adapted for UV (includes lithography objectives even without an explicit UV reference)

G02B 17/0896: With means for varying the magnification or providing a plurality of image planes from a single pupil (same rules as for G02B 17/0694)

The following table gives examples of patent documents classified in the subgroups of G02B 17/06 or G02B 17/08:

{using two curved mirrors (G02B 17/0864, G02B 17/0896 takes precedence)}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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References
Limiting references

This place does not cover:

Having non-imaging properties

G02B 17/0668

With variable magnification or multiple imaging planes, including multispectral systems

G02B 17/0694

{on-axis systems with at least one of the mirrors having a central aperture}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{using three curved mirrors (G02B 17/0864, G02B 17/0896 take precedence)}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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References
Limiting references

This place does not cover:

Having non-imaging properties

G02B 17/0668

With variable magnification or multiple imaging planes, including multispectral systems

G02B 17/0694

{on-axis systems with at least one of the mirrors having a central aperture}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{on-axis systems with at least one of the mirrors having a central aperture}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{having a field corrector only}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{wherein the system is made of a single block of optical material, e.g. solid catadioptric systems}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{having a pupil corrector}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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{the corrector having at least one aspheric surface, e.g. Schmidt plates}
Definition statement

This place covers:

Illustrative example of subject matter classified in this group:

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Condensers, {e.g. light collectors or similar non-imaging optics} (for microscopes G02B 21/08)
Definition statement

This place covers:

Optical condensers, light collectors and similar non-imaging optics.

References
Limiting references

This place does not cover:

Illumination arrangement in microscopes

G02B 21/08

Informative references

Attention is drawn to the following places, which may be of interest for search:

Lighting

F21V

Solar heat collectors

F24S

Optical elements combined with semiconductor receivers

H01L 31/0232

Optical elements combined with semiconductor emitters

H01L 33/58

Special rules of classification

Concerning optical arrangements for illumination from LEDs, the practice is to classify in G02B 19/0061 (or G02B 19/0066 for LED arrays) and in one or more other classes under G02B 19/00 according to the optical means employed. In particular:

  • Arrangements involving refractive surfaces only, at least one surface having optical power, and adapted for a single LED are classified in G02B 19/0061 and in G02B 19/0014. For example:

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  • Arrangements involving reflective surfaces only, at least one surface having optical power, and adapted for a single LED are classified in G02B 19/0061 and in G02B 19/0023.
  • Arrangements involving reflective and refractive surfaces adapted for a single LED are classified in G02B 19/0061 and in G02B 19/0028. For example:

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In the above examples, the classification G02B 19/0071 is additionally given in the case of adaptation to illuminate a complete hemisphere or a plane extending 360° around the source. For example, the following arrangement would be classified in G02B 19/0061, G02B 19/0028 and G02B 19/0071:

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Microscopes (eyepieces G02B 25/00; polarising systems G02B 27/28; measuring microscopes G01B 9/04; microtomes G01N 1/06; scanning-probe techniques or apparatus G01Q)
Definition statement

This place covers:

Optical microscopes including conventional microscopes, as well as laser scanning microscopes, confocal microscopes, fluorescence microscopes, video microscopes or optical aspects of surgical microscopes.

References
Limiting references

This place does not cover:

Eyepieces

G02B 25/00

Polarising systems

G02B 27/28

Ophthalmic microscopes

A61B 3/13

Measuring microscopes

G01B 9/04

Microtomes

G01N 1/06

Scanning probe microscopes (SPM), e.g. scanning tunnelling microscopes (STM), atomic force microscopes (AFM), scanning near-field optical microscopes (SNOM), magnetic force microscopes (MFM)

G01Q

Electron microscopes

H01J 37/00

Informative references

Attention is drawn to the following places, which may be of interest for search:

Medical aspects of surgical microscopes

A61B 90/36

Special rules of classification

Non-confocal fluorescence microscopes, including visible and infrared ones, are classified in G02B 21/16

Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies (diagnostic instruments A61B); Viewfinders (objectives G02B 9/00, G02B 13/00, G02B 15/00, G02B 17/00; eyepieces G02B 25/00); Optical aiming or sighting devices (non-optical aspects of weapon aiming or sighting devices F41G)
Definition statement

This place covers:

  • Telescopes, e.g. binoculars;
  • Periscopes;
  • Instruments for viewing the inside of hollow bodies e.g. endoscopes
References
Limiting references

This place does not cover:

Optical design aspects or layout of objectives

G02B 9/00, G02B 13/00, G02B 15/00, G02B 17/00

Optical design aspects or layout of eyepieces

G02B 25/00

Medical diagnostic instruments in general

A61B

Endoscopes specifically for medical applications, e.g. structural aspects for the intended medical procedure

A61B 1/00

non-optical details of weapon aiming or sighting devices

F41G

Eyepieces; Magnifying glasses (simple lenses G02B 3/00)
Definition statement

This place covers:

Eyepieces (e.g. for microscopes or telescopes); Magnifying glasses

References
Limiting references

This place does not cover:

Viewfinders for photographic apparatus

G03B 13/02

Informative references

Attention is drawn to the following places, which may be of interest for search:

Simple lenses

G02B 3/00

Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating (mechanically operable parts of lighting devices for the control of light order F21V; specially adapted for measuring characteristics of light G01J; devices or arrangements, the optical operation of which is modified by changing the optical properties of the medium of the devices or arrangements G02F 1/00; control of light in general G05D 25/00; control of light sources H01S 3/10, H05B 39/00H05B 47/00)
Definition statement

This place covers:

Optical devices or arrangements using movable or deformable optical elements for controlling the intensity, colour, phase, polarisation or direction of light, e.g. switching, gating, modulating

Relationships with other classification places

Optical devices or arrangements the optical operation of which involves changing the optical properties of the material used by an applied field or force G02F 1/00

References
Limiting references

This place does not cover:

Mechanically operable parts of lighting devices for the control of light order

F21V

Measuring characteristic of light, spectroscopy

G01J

Devices or arrangements, the optical operation of which is modified by changing the optical properties of the medium of the devices or arrangements

G02F 1/00

Control of light in general

G05D 25/00

Control of light sources

H01S 3/10, H05B 39/00 - H05B 47/00

Special rules of classification

Looping references between G02B 26/00 and G05D 25/00 have been identified. Until this inconsistency is resolved, the current classification practice in CPC is as follows: Reference G05D 25/00 is non-limiting in the main group G02B 26/00.

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Gyricon

The term gyricon refers to a type of electronic paper in the form of a thin layer of transparent plastic in which millions of small "bichromal" beads (i.e. with hemispheres of two contrasting colors) are randomly dispersed. When a voltage is applied, the beads rotate to present one colored side to the viewer, allowing images such as text and pictures to be displayed.

{based on interference in an adjustable optical cavity (interference filters G02B 5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J 3/26)}
Definition statement

This place covers:

Systems providing spectral filtering by an adjustable, e.g. variable spacing, optical cavity.

Relationships with other classification places

Adjustable Fabry-Perot devices in spectroscopy applications, e.g. as monochromators or for spectral analysis are classified in G01J 3/26. A further classification in G02B 26/001 is optional.

References
Limiting references

This place does not cover:

Non adjustable interference filters

G02B 5/28

Devices or arrangements using multiple reflections in spectrometry or monochromators

G01J 3/26

{based on the rotation of particles under the influence of an external field, e.g. gyricons, twisting ball displays (based on orientable dipolar particles G02F 1/172; based on electrophoresis G02F 1/167)}
Definition statement

This place covers:

All documents describing rotating particle displays ("gyricons" etc.) are to be classified in G02B 26/026, for example:

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However, electrophoretic displays (involving particles moving linearly under the influence of an electric field) are classified in G02F 1/167.

Control of the intensity of light based on variable absorption of orientable dipolar particles is classified in G02F 1/172.

References
Limiting references

This place does not cover:

Displays based on electrophoresis

G02F 1/167

Displays based on orientable dipolar particles

G02F 1/172

{the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B 26/0825 takes precedence; micromechanical devices in general B81B)}
Definition statement

This place covers:

G02B 26/0833 is directed to optical MEMS per se with a high emphasis on the optical properties of the devices and their interaction with other optical elements in the apparatus.

References
Limiting references

This place does not cover:

Deformable or flexible reflecting membrane devices

G02B 26/0825

Informative references

Attention is drawn to the following places, which may be of interest for search:

Mictomechanical devices in general

B81B

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

DLP

Digital Light Processing

DMD

Digital Micromirror System

MEMS

Microelectrical Mechanical System

MOEMS

Microoptical Electro Mechanical System

Optical systems or apparatus not provided for by any of the groups G02B 1/00 - G02B 26/00, G02B 30/00
Definition statement

This place covers:

Other optical systems, for example, head-up displays, head-mounted displays, beam-shaping systems, beam-splitting or combining systems, systems for producing stereoscopic or three-dimensional effects, polarising systems, diffraction systems.

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Showcases

A47F

Optical toys

A63H 33/22

Designs or pictures characterized by special light effects

B44F 1/00

Special rules of classification

Further details of other subgroups of G02B 27/00, like G02B 27/10 through G02B 27/44, see the definition of G02B 27/01.

The following IPC group is not used for classification: G02B 27/18, see the relevant subclasses according to the projector type. The subclass G02B 27/20 is, however, used for laser pointers or the like.

Head-up displays
Definition statement

This place covers:

Devices for superimposing a synthetic image on a background scene by projection of a synthetic image on a background scene on a partially transparent surface:

  • head mounted, e.g. pilot helmets
  • non head mounted, e.g. windscreen of a car
  • optical features
  • mechanical features
  • display position adjusting means not related to the information which is to be displayed
  • sight systems

Examples of subject matter covered are:

Projection of flight or drive data on the windscreen of a plane or of a car (see for example US2011298693 paragraphs [0022],[0023], figure 1).

Vizor of pilots helmet with a partially transparent surface ("helmet mounted displays")

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Special rules of classification

Further details covered by G02B 27/01 and not provided for in any of its subgroups is provided for in the subgroups of Indexing Codes G02B 27/01 and below. Classification is obligatory.

Further details of other subgroups of G02B 27/00

G02B 27/10: Beam splitting or combining systems

The scheme comprises subgroups covering specific structural technical solutions ("means") and a parallel set of subgroups covering the purposes of the devices, independently of the specific type of beamsplitter used.

The subgroup G02B 27/10 is intended for beamsplitting/combining systems which cannot be given any lower means subgroup in the scheme. In general, documents should be assigned at least one means subgroup and at least one purpose subgroup.

Purpose Subgroups: Examples

G02B 27/1006 for splitting or combining different wavelengths

For wavelength specific documents which are not covered by any lower entry.

All color imaging related documents are in the color sensing subgroup (G02B 27/1013) or in one of the color reproducing subgroups (G02B 27/102 and subgroups). These subgroups are not limited to RGB devices and cover also non visible or pseudocolor devices as long as the final image is intended for the human viewer.

For color or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors.

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The devices must be imaging devices, including line scanning. Other spectral sensing devices belong to G02B 27/1006.

For generating a color image from monochromatic image signal sources.

Essentially covers color generating systems not specifically designed for a particular type of SLM, e.g. illumination systems combining multiple light sources

For use with reflective spatial light modulators

WO0038432

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US2001000973

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Having a single light modulator for all colour channels

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For use with scanning systems

Beams splitter/combiner arrangement for color scanning display arrangements

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For use with transmissive spatial light modulators

The "classic" 3 LCD projector;

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Using a single light modulator for all colour channels

for example time sequential led sources used with a single SLM, US2006196944

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could be extended to light pipes: EP1003064

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For splitting or combining a plurality of identical beams or images, e.g. image replication.

Quite a few documents deal with obtaining multiple identical copies of a beam. The numbers of beam should be four or more, color aspects are not relevant for this class.

US2006082890: construction laser

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DE3502382: Laser beam replication.

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Characterized by manufacturing or alignment methods, e.g. assembly of cross dichroic cubes.

media81.png US5455678

media82.pngEP0947869

The subgroup is also relevant for mechanical aspects and devices where the alignment of the beams requires a particular construction (equivalent to G02B 7/00 for beamsplitters).

For enhancing image performance, e.g. resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view. Covers sensing or imaging devices where fields are either

  • overlapping, e.g. dual resolution or pixel shifted systems, to increase the perceived resolution or
  • abutted, save some border blending, for dividing or combining a larger field of view into or from subfields, e.g. detector or display tiling, image slicing.

Resolution should be taken in a broad sense, including high dynamic range systems.

GB2222892: high resolution CRT with a low resolution LCD

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WO2008129552: "foveal" devices, narrow HD field with a large low resolution field

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WO98/10402: mosaic displays

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CA1073715: Slicing/dividing an image

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For sampling a portion of a beam or combining a small beam in a larger one, e.g. wherein the area ratio or power ratio of the divided beams significantly differs from unity, without spectral selectivity. Sampling devices for high power laser, laser beam insertion.

US4746205

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GB2027222

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Means Subgroups: Examples

The decisive criterion is the physical principle leading to the splitting or combining, and not other aspects of the device. For example a cube beamsplitting prism operates by reflecting (part of) the beam, and hence operates by reflection, even though it also has refracting surfaces. Following the optical path, the relevant surface marks the boundary between the single beam and the multiple beams.

IPC classes G02B 27/12 and G02B 27/14 refer to "refraction only" or "reflection only" but some devices use both reflecting and refracting beamsplitting structure, e.g. US6400512 :

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Applying strictly the IPC wording of the headers G02B 27/12 or G02B 27/14, such documents would not have their details classified in these subgroups. For the purpose of CPC classification, the limitation "only" should be disregarded. The above document would therefore be classified in G02B 27/12 (or a subgroup thereof) and G02B 27/14 (or a subgroup thereof).

Operating by diffraction only

Polychromatic diffractive combiners may be additionally classified in G02B 27/1013 or G02B 27/102.

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US2006109876

For use with monochromatic radiation only, e.g. devices for splitting a single laser source

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Since diffractive elements are intrinsically wavelength dependent, purely monochromatic devices represent special applications. G02B 27/1086 and G02B 27/1093 cover passive diffractive devices only

Operating by refraction only.

This subgroup comprises inter alia systems using birefringent materials for standard beamsplitting applications, for example not polarization relevant (polarization beamsplitters G02B 27/283).

The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive power.

FR2889746: beam splitting takes place at 110a,110b

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In G02B 27/123 the optical path should be branched. Fly eye beam shaping devices belong to G02B 27/0961, lens arrays per se in G02B 3/0006.

The splitting element being a prism or prismatic array, including systems based on total internal reflection.

The class covers both refracting deviating prisms, including spectral deviation and systems where the splitting/combining is achieved by total internal reflection without reflecting coatings:

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US2005174658

Operating by reflection only

For example a non conventional reflective beamsplitter as in US6266359:

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Using dichroic mirrors

For simple dichroic mirror arrangements transmitting a wavelength band and reflecting the other. G02B 27/1006 covers color splitting in general, and RGB image analysis or synthesis is covered by G02B 27/1013 or G02B 27/102 and lower.

Coating structure, e.g. thin films multilayers.

When the focus is the structure of the beam splitter coatings (thicknesses, materials, refractive indexes) including single thin metallic layers.

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JP58208701: a polarisation independent multilayer semi-transparent coating.

Macroscopically faceted or segmented reflective surfaces

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The segmentation here is macroscopic, compare with G02B 27/147.

Using partially transparent surfaces without spectral selectivity (G02B 27/147 takes precedence) for conventional half-mirrors.

US5198930:

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Having sequential partially reflecting surfaces

GB2153546

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With a tree or branched structure

EP1626585

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Using averaging effects by spatially variable reflectivity on a microscopic level, e.g. polka dots, chequered or discontinuous patterns, or rapidly moving surfaces (G02B 27/1086 takes precedence).

US4941012

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The subgroup also covers time averaging systems such as chopper mirrors rotating at high speed to emulate a beamsplitter.

JP52011894:

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Devices incorporating crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes. Not limited to three channels

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Including stacked surfaces having at least one double-pass partially reflecting surface

A special type but common type of beamsplitter where at least the front surface is crossed twice. Common for RGB angular separation, the last surface can be fully reflective.

US2009251783

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Used as aids for focusing

Covers split prisms historically used to focus an image in reflex cameras and has almost no activity.

There are two groups for autostereoscopic systems (i.e. systems in which left and right images projected to the left and right eyes of an observer who is not required to view the images through special glasses optical systems placed adjacent to the eyes:

Autostereoscopic systems which comprise lenticular arrays or parallax barriers are classified in G02B 30/27.

Autostereoscopic displays which do not comprise lenticular arrays or parallax barriers, for example systems in which the left and right images are projected directly into the left and right eyes of the observer, are classified in G02B 30/26. An example of such a display is shown in the figure below

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Concerns volumetric displays, i.e. in which an image is built up from image elements distributed over a three-dimensional volume. An example is US2007/0242324, in which visible fluorescence is excited at the crossing points of two scanned invisible lasers:

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There are three subgroups:

The image being built up using a stack of two dimensional planes, e.g. US 2002/0130820:

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The volume being generated by a moving (vibrating or rotating) surface, e.g. US6115006:

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Projecting an aerial or floating image, typical examples of which would be WO02/061492:

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or WO95/19584

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G02B 27/42: Diffraction optics

G02B 27/42 deals with systems comprising a DOE (diffractive optical element) having a significant interaction with another component of the optical system. If the document also discloses significant details about the diffractive element as such, it should be additionally classified in G02B 5/18. This subgroup contains documents in which the diffractive effect results from a purposeful design of a DOE. It does NOT include documents in which light is merely diffracted by an aperture, an edge or a particle. G02B 27/4266 is an exception to this rule. G02B 27/42 is essentially structured into two major groups:

.. imaging systems (G02B 27/4205 and lower)

.. non-imaging systems (G02B 27/4233 and lower).

Besides this major differentiation, there are three further divisions:

.. physical properties of the DOE:

polarization G02B 27/4261,

thermal G02B 27/4283,

.. sequential DOEs G02B 27/4272 and G02B 27/4277

.. theory, models G02B 27/4266

In deciding whether a system is an imaging system or a non-imaging system, concepts such as image resolution or extended objects/images are strong hints towards imaging systems. On-axis point-like objects/images are pointers to non-imaging systems. It is important to note that G02B 27/4205 (and lower) and G02B 27/4233 (and lower) relate to the specific role played by the DOE in the system: a DOE within an imaging system, but merely deviating light for illumination purposes in a subsystem of the imaging system, is classified in G02B 27/4233 (or lower).

Specific rules

G02B 27/4233 (and lower) should preferably not contain documents which have a more specific class e.g. G02B 6/00 (optical fibers, waveguides), H01S (laser pulse compression), G01J (spectroscopy).

G02B 27/4238 should contain no document from the field of optical pick-up devices (these documents should be classified in G11B 7/1353).

G02B 27/425 should preferably contain no document about mask illumination in a lithographic apparatus (these documents should be classified in G03F 7/70158). This should not be confused with a DOE projecting an image of the mask onto a wafer, which is classified in G02B 27/4222).

G02B 27/4272 and G02B 27/4277 relate to plural diffractive elements positioned sequentially along the optical path means that the distance between sequential diffractive elements is large enough to ensure that each period of the subsequent grating receives diffracted light from several periods of the previous grating, i.e. far-field diffraction. For instance, DOEs which, at least in certain portions of the DOE are in direct contact or multilayered DOEs are normally not plural diffractive elements in the sense of G02B 27/4272 and G02B 27/4277.

When allocating G02B 27/42, consider also the relevance of the following classes in G02B relating to diffraction or gratings:

G02B 1/005 (photonic crystals)

G02B 1/118 (moth-eye anti-reflection structures)

G02B 5/0252 (diffusers using holographic or diffractive means)

G02B 5/18 (diffraction gratings per se)

G02B 5/203 (filters using holographic or diffractive means)

G02B 5/32 (holographic optical elements)

G02B 26/0808 (controlling direction of light)

G02B 26/106 (scanners using movable diffraction gratings)

G02B 27/0944 (beam shaping using diffractive optical elements)

G02B 27/1086 (beam splitting and combining by diffraction)

G02B 27/46 (spatial filters)

G02B 27/58 (superresolution, apodization)

G02B 27/60 (systems using moiré fringes)

Exemplary drawings for G02B 27/42

Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect (G02B 27/60 takes precedence)

G02B 27/4205

having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevantmedia114.pngmedia115.png e.g. WO2008081070: microdisplay (110) projected by diffractive beam expander (50)

G02B 27/4211

correcting chromatic aberrations (G02B 27/0056, G02B 27/4222, G02B 27/4227 take precedence) media116.pngmedia117.png e.g. US6130785: eyepiece (800) with diffractive surfaces (28b, 29b)

G02B 27/4216

correcting geometrical aberrationsmedia118.pngmedia119.png e.g. US2002027712: L6 comprises DOE; monochromatic aberrations are smaller than compared to a solution without DOE; fig 25B shows polychromatic MTF

G02B 27/4222

in projection exposure systems, e.g. photolithographic systemsmedia120.pngmedia121.pngmedia122.png e.g. EP1022589: projection system (12) including DOE (21), illumination system (20), reticle (11)

G02B 27/4227

in image scanning systemsmedia123.pngmedia124.pngmedia125.png e.g. US2007211324: at least one of the lenses (2, 4, 6, 8) includes a DOE

G02B 27/4233

having a diffractive element [DOE] contributing to a non-imaging application (diffusers having a diffractive element G02B 5/0252; filters having a diffractive element G02B 5/203; systems for controlling the direction of light having diffractive elements G02B 26/0808; scanning systems having diffractive elements G02B 26/106; beam shaping systems using diffractive optical elements G02B 27/0944; beam splitting or combining systems operating by diffraction G02B 27/1086 ) => consists of non-imaging systems whose application has no dedicated class B1 to B7 media126.png e.g. US2007024978: achromatized scanner with rotating prisms (14, 15); due to DOE (18), different wavelengths are scanned at the same angle

G02B 27/4238

in optical recording or readout devices (optical pick-up devices such as for CD, DVD or BD reader or recorder using diffraction optics G11B 7/1353 ) => comprises mostly older documentsmedia127.png e.g. US4019817: DOE (21), color image carrier film (12), monochrome recording film (10); use of diffraction screens (21) for recording colour data as diffraction fringes (10)

G02B 27/4244

in wavelength selecting devices (spectrometry G01J)media128.png e.g. WO2011016002: DOE (82) with a conical grating (84) for reflecting light at different wavelength-dependent angles

G02B 27/425

in illumination systems (mask illumination systems in photolithographic systems G03F 7/70158)media129.png e.g. US2009310377: projection-type vehicle lamp with a light source (101) and a projector lens (107) comprising a DOE on one of its surfaces

G02B 27/4255

for alignment or positioning purposes (optical displacement encoding scales G01D 5/347)media130.pngmedia131.png e.g. WO2006028183: substrate (24) is formed with diffraction elements (23); the diffracted light spots are used to align the optical axis of the lens system (22)

G02B 27/4261

having a diffractive element with major polarization dependent propertiesmedia132.pngmedia133.png e.g. US2008117508: polarizing beamsplitter (23) with periodic grating structures (see fig 2)

G02B 27/4266

Diffraction theory; Mathematical models => background on diffractive patterns; diffracted wave propagation; a real DOE is not necessarily present

G02B 27/4272

having plural diffractive elements positioned sequentially along the optical pathmedia134.png e.g. US5808799: two sequentially diffracting surfaces (72, 74)

G02B 27/4277

G02B 27/4283

having a diffractive element with major temperature dependent propertiesmedia135.png e.g. US5808799: The diffractive pattern (42) of the athermalization element (34) compensates temperature induced changes in the focal length of the lens assembly (16)

G02B 27/4288

having uniform diffraction efficiency over a large spectral bandwidthmedia136.pngmedia137.png e.g. US2010134889: DOE (1) with a resin layer (26) and a glass layer (27) having 100% diffraction efficiency over the visible bandwidth

G02B 27/4294

in multispectral systems, e.g. UV and visiblemedia138.pngmedia139.png e.g. WO2010100648, imager forming images in two spectral bandwidths (1, 2) and comprising DOE (120), which diffracts light at different diffraction orders

G02B 27/44

Grating systems: NOT IN USE IN CPC(documents classified in G02B 27/42 and subgroups).