| 摘要 |
PURPOSE:To secure high distance measurement precision by compensating fluctuations of an emitted-light output. CONSTITUTION:A monostable multivibrator MM is triggered with pulses phi0 to generate pulses phi1-phi3. When the pulse phi1 is applied to a projector LED1, light is emitted to an object 1 intermittently and its freflected light is detected by a photodiode PD. Then, an LED2, LED3 and LED4 turn on selectively according to the position of the object 1 which is at close distance, intermediate distance and long distance. At this time, the time width of the pulse phi1 varies with a circuit constant varying with temperature, and the gate time of an analog switch S1 varies, thereby varying the luminous intensity of the LED1. As a result, the time when the reflected light is integrated 5 varies to compensate the output variations of the LED1. |
