(under subclass 201) Subject matter wherein the illumination which falls on the photocell comes from a light source which comprises a cathode-ray tube and said photocell electrically controls the cathode-ray tube.
(1) Note. See (4) Note under the definition of subclass 200 for a general distinction between subject matter of this class (250) and Class 315 and Class 348.
SEE OR SEARCH THIS CLASS, SUBCLASS:
202, for optical systems wherein the photocell follows the edge of a pattern under control of the illumination.
SEE OR SEARCH CLASS
315, Electric Lamp and Discharge Devices: Systems,
10+, for photocell circuits in which the photocell controls a cathode-ray tube but does not include the combination of mechanical devices, optical devices or specific input sources of information. Examples of cathode-ray tube control of this class (315) include means to control the intensity of the tube, means to automatically control the contrast of said tube under quiescent conditions or means to generate a scale or grid on the face of said tube. 340, Communication: Electrical, including a cathode-ray tube in combination with an input circuit for processing a signal for the purpose of communication. Note appropriate subclasses, specifically
146.3, and 343.
348, Television,
602+, for control of brightness or contrast of display on a cathode-ray tube dependent on ambient light sensed by photocells.
