Apparatus for detecting the presence and position of an object

摘要

Here is disclosed a photoelectric detector comprising first and second light sources respectively having different light emitting areas, a photoelectric transducer member adapted to receive the light emitted from these light sources and then reflected on an object to be detected, and a signal processing circuit functioning to separate electric signals corresponding to the first and second light sources from an output of the photoelectric transducer member and to compare these separated two electric signals to each other so that presence or absence and a position of the object are detected on the basis of such comparison of the two electric signals.