(under the class definition) Subject matter including opaque or translucent light limiting or controlling means such as a diaphragm, hood, curtain, aperture plate, framing plate, light baffle or shield.
(1) Note. The light-limiting or controlling means may be positioned either in the light path to block a portion of the light from the lamp or may be positioned near the light path to reduce undesired light to or from the light path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70, for means to eliminate Keystone effects.
75, for light shields, etc., in cabinet-type projectors.
79, for a hood which may structurally connect the projector and viewing screen.
88, for a projector having a shutter. 98, for specular reflectors in the light path.
SEE OR SEARCH CLASS
359, Optics: Systems (Including Communication) and Elements,
738+, for a lens in combination with a diaphragm or mask of general utility and subclasses 227+ for light control by an opaque element or medium movable in or through a light path.
369, Dynamic Information Storage or Retrieval,
118+, for a slit aperture in an optical system for recording or reproducing sound.