| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the impact of environmental temperature change as much as possible, by reducing the influence of reflection light from a reflector on a detection element for monitor.SOLUTION: In a reflective sensor device having a LED3, and a light-receiving element 4 for receiving light from a reflector 10 on the basis of the light emission from the LED3, the light-receiving element 4 and a photodetector 13 for temperature compensation are arranged via a light-shielding wall 7, so as to block the light from the LED3, and an upper surface light-shielding wall 16 is provided on the upper surface (on which the reflection light from the reflector impinges) of a sealing part 14 sealing the photodetector 13 for temperature compensation. A light shielding plate may be provided in the photodetector 13 for temperature compensation itself. A constant current is applied by a constant current circuit to the photodetector 13 for temperature compensation, and the sensor output is subjected to temperature compensation, by calibration based on the variation of the photodetector 13 for temperature compensation.SELECTED DRAWING: Figure 1 |
