|  | G |
SECTION G — PHYSICS

INSTRUMENTS

|  | G02 |
OPTICS (making optical elements or apparatus Fulltext... Hierarchy... Expanded...B24B, Fulltext... Hierarchy... Expanded...B29D, Fulltext... Hierarchy... Expanded...C03, or other appropriate sub-classes or classes)

|  | G02B |
OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS (Fulltext... Hierarchy... Expanded...G02F takes precedence; measuring-instruments, see the relevant sub-class of class Fulltext... Hierarchy... Expanded...G01, e.g. optical rangefinders Fulltext... Hierarchy... Expanded...G01C; testing of optical elements, systems, or apparatus Fulltext... Hierarchy... Expanded...G01M 11/00; spectacles Fulltext... Hierarchy... Expanded...G02C; sound lenses Fulltext... Hierarchy... Expanded...G10K 11/06; electron and ion "optics" Fulltext... Hierarchy... Expanded...H01J; X-ray "optics" Fulltext... Hierarchy... Expanded...H01J, Fulltext... Hierarchy... Expanded...H05G 1/00; optical elements structurally combined with electric discharge tubes Fulltext... Hierarchy... Expanded...H01J 5/16, Fulltext... Hierarchy... Expanded...H01J 29/89, Fulltext... Hierarchy... Expanded...H01J 37/22; microwave "optics" Fulltext... Hierarchy... Expanded...H01Q; combination of optical elements with television receivers Fulltext... Hierarchy... Expanded...H04N 5/72)

|  | G02B |
Note(s) In this sub-class, the following terms are used with the meanings indicated: "Simple lens or prism" denotes a single lens or prism. "Compound lens or prism" denotes an optical member, the constituents of which either are close together without air-space or (except in group Fulltext... Hierarchy... Expanded...G02B 11/00) are "in broken contact", i.e. with the air-space between the constituents having no essential optical influence "Objective" denotes a lens or an optical system designed to produce a real image of a real object. "Eyepiece" denotes a lens or an optical system designed to produce a virtual image for viewing by the eye or by another optical system. "Front" and "rear" are determined by looking from the more distant conjugate. "Optical" applies not only to visible light but also to ultra-violet and infra-red radiations.

|  | G02C |
SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES (trial frames for opticians' use Fulltext... Hierarchy... Expanded...A61B 3/04; goggles or eyeshields not having the same features as spectacles Fulltext... Hierarchy... Expanded...A61F 9/00)

|  | G02C |
Note(s) This sub-class also includes contact lenses for the eyes, monocles, pince-nez, and lorgnettes.

|  | G02F |
CONTROLLING THE INTENSITY, COLOUR, PHASE, POLARISATION, OR DIRECTION OF LIGHT BEAMS, e.g. SWITCHING, GATING, MODULATING, OR DEMODULATING; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS (optical transfer means between sensing member and indicating or recording part in connection with measuring Fulltext... Hierarchy... Expanded...G01D 5/26; devices in which mathematical operations are carried out with optical elements Fulltext... Hierarchy... Expanded...G06G 9/00; electrical signal transmission systems using optical means to convert the input signal Fulltext... Hierarchy... Expanded...G08C 19/36; information-recording by electric or magnetic means and reproducing by sensing optical properties Fulltext... Hierarchy... Expanded...G11B 11/00; static stores using optical elements Fulltext... Hierarchy... Expanded...G11C 13/04; transmission systems employing electromagnetic waves other than radio waves, e.g. light, infra-red radiation, Fulltext... Hierarchy... Expanded...H04B 9/00; television Fulltext... Hierarchy... Expanded...H04N) [2]