| 摘要 |
PURPOSE:To shorten the distance measurement time without lowering the distance measurement precision by integrating and comparing the output signal of a photodetecting element with a specific voltage and switching input registers of an integration circuit corresponding to the level. CONSTITUTION:A level decision circuit 60 compares the output of the integration circuit 50. i.e., an integrated voltage Vi with the reference V1 selected with a switch 62 and outputs the comparison result, i.e., an output voltage Vo to a CPU 70. While light projection is repeated. the switch 62 is turned ON to a reference voltage source 63 at the moment the integrated voltage Vi reaches V2 of a reference voltage source 64, and while similar operation is repeated. the operation is ended once the integrated voltage Vi reaches the reference V1. Further, while the light projection is repeated, the switch 6 is connected to the side of an input resistance 53 and the switch 62 is connected to the side of the reference voltage source 63 once the integrated voltage Vi reaches V2 of the reference voltage source 64 to attenuate the input signal to the integration circuit 50 to 1/10. Consequently, higher resolution than before is obtained. |
