| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect an object to be detected where light can be easily transmitted, by gradually decreasing a set test current as an original supply current value for detecting the minimum value of the output signal of a photo detector, and by adding a specific test current value when setting a photosensor device body to a test mode. SOLUTION: When a power supply is turned on by starting the operation of, for example, an automatic ticket machine where a photosensor device is incorporated, a photosensor device body is set to a test mode. A test current value being adjusted by a current limitation resistor 3 is supplied to a light- emitting device 1 for emission. When there are no objects to be detected between the light-emitting device 1 and a photo detector 10, the test current value is set to a signal value without detection from a detection circuit 11. Then, a new test current value is obtained by subtracting a specific minute current value from the test current value for supplying to the light-emitting device. The minimum output current value is compared with a down reference current value for stopping the function of the photosensor device. Then, when the comparison value is not large, the minute current value is added for determining a supply current value.</p> |
