| 摘要 |
<p>PURPOSE:To provide shaping function of an output waveform of a signal detected from a photodetection output by connecting a light emitting element to a photodetector in series to form a positive feedback circuit, and connecting a bypass circuit for limiting a value to be self-recovered to the photodetector in a negative direction in parallel. CONSTITUTION:A light emitting element 2 like a light emitting diode LED and a photodetector 3 like a phototransistor P.Tr mounted oppositely at a predetermined interval are connected in series to form a positive feedback circuit, a predetermined light emitting current is supplied to the element 2, and a bypass circuit 4 made of a constant-current circuit for limiting a value to be self-recovered to the element 3 in a negative direction is connected in parallel with the element 3. Thus, a switch mechanism having excellent switching characteristic and small erroneous operations including chattering, etc., can be formed. Further, the number of terminals can be reduced, an assembling is facilitated, and the cost of an apparatus can be reduced.</p> |
