| 摘要 |
An object of the present invention is to enable the detection of the presence/absence of an object over a plurality of detection areas without using a plurality of light-receiving devices and light-emitting devices. A sensor detects the presence/absence of an object in a detection area where a light-emitting area of a light-emitting device and a light-receiving area of a light-receiving device are overlapped with each other, and includes: a power supply unit that outputs a driving current I of the light-emitting device such that its current value is variable; a control unit that has the function of controlling the power supply unit to change in magnitude of the driving current I of the light-emitting device, and determining the presence/absence of an object based on an output from the light-receiving device to output the result of determination as a detection signal; and an output signal 50 that converts the detection signal into an analog signal to output the converted signal as a signal alpha.
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