(under subclass 216) Subject matter having means for moving an element of the optical system.
(1) Note. Examples of such means are means for adjusting the photocell so that its axis is aligned with the optical axis, a hand crank for adjusting the photocell to sense in a desired direction or a vehicle upon which the entire photocell apparatus is mounted.
SEE OR SEARCH THIS CLASS, SUBCLASS:
218, for photocell sensing means in which a fluent material is moved through the optical path between light source and photocell.
223, and 224, for photocell sensing means in which an inanimate object is moved to or from or while in the optical path.
229+, for photocell sensing means having a light valve in the optical path, particularly indented subclass 231, where the light valve is adjusted in accordance with an external physical quantity and subclasses 232+, where the light valve continuously moves to chop the light.
559.01+, and 566+, for similar subject where the object is a coded record or a web, strand, strip or sheet which is conveyed to the sensing point.
