| 摘要 |
PROBLEM TO BE SOLVED: To provide a photodetector which completely prevents the erroneous determination that "a detected object is present" and which prevents the decrease in light sensitivity and resistance to a power line noise.SOLUTION: A signal processing circuit 8 detects a noise pulse by a first gate signal (H) synchronized with a first light-emitting pulse and an output (G) of a comparator circuit 7, and detects synchronous light by a second gate signal (I) synchronized with a second light-emitting pulse and the output (G) of the comparator circuit 7. |
