| 摘要 |
PURPOSE:To shorten a total range finding time and to make the range finder favorable to a shutter opportunity by detecting an integrated voltage and simultaneously counting the number of light projecting times while the light is being projected on an object and then, finishing range-finding when either satisfies a prescribed condition. CONSTITUTION:A light projection circuit 10 is operated by a CPU 80, and a light projection signal is generated and a near infrared ray emitting element 14 is driven so as to start projecting light. And after a time T1 is obtained after projecting light, a switch 7 is turned on so as to integrate only for a time T2. When the integration is finished, projecting the light is stopped, and also, the switch 7 is turned on, and after standing by only for a time T3, a count-up signal is generated, '1' is added to a number of times Nf. After repeatedly performing the aforesaid operation only the previously decided number of times, a voltage between terminals of an integrating capacitor 63, that is, the integrated voltage is outputted to an ADC 70, the result is converted by the ADC 70 into a digital signal so as to be outputted to the CPU 80. the range-finding is finished when the number of times reaches a prescribed number of times, or when the integrated voltage reaches a prescribed value, and a distance signal is obtained from a value obtained at that point of time. |
