| 摘要 |
PURPOSE:To reject noise ad to enable to continuously extend the photodetection signal, by providing a D type FF of edge trigger type with a photodetector, in a reflection type photoelectric switch which incorporates the projector and the photodetector in one case. CONSTITUTION:Modulated light emitted from a light emitting circuit 3 of a light emitter 1 is detected at a photodetection circuit 6 of a photodetector 6, the output of the circuit 6 is amplified 7 and level-discriminated 8, and the output is input to a D type FF15 of edge trigger type. FF15 reads in the data at the trailing of an oscillation circuit 2 and set at the trailing of the first oscillation signal after the absence of data, then the output is kept at H level while the photodetection signal is present. The output of FF15 is integrated 10 and wave-shaped 11, and an output circuit 12 is operated with the output. When the path of modulation light is interrupted and the output of the circuit 8 is absent, the output of FF15 is at L level and the circuit 12 is inverted. Since FF15 does not read in the data in the timing other than the trailing of oscillation output, it is not malfunctioned with noise. |
