(under subclass 1) Subject matter where the digital pattern carrier is read by an optical device.
(1) Note. For optical shaft encoders in combination with a photocell absent any signal processing circuitry, search Class 250, subclass 231.
SEE OR SEARCH THIS CLASS, SUBCLASS:
137, for analog to or from digital conversion using optical devices.
SEE OR SEARCH CLASS
250, Radiant Energy,
231, for a photocell shaft encoder, subclass 271 for invisible radiant energy coded record readers, subclasses 555+ for coded record controlled photocell circuits and subclasses 566+ for coded record reading optical or
prephotocell systems absent any signal processing circuitry. 346, Recorders,
225, and 246 through 264 for recording of a code disc by scanning of light.
369, Dynamic Information Storage or Retrieval,
100+, for information retrieval from an optical information carrier.
