| 摘要 |
PURPOSE:To monitor an adjustment state and to make an accurate focus adjustment by outputting dummy data corresponding to a range finding signal from a CPU and monitoring the dummy data. CONSTITUTION:When range finding is executed, a timer T2 (90ms) is set at the start of the range finding and the range finding data is inputted to the CPU 1 the 90ms of the timer T2 later. An LED illuminates during the range finding, but a capacitor C3 begins to be recharged on the illumination. Its charging current, however, increases considerably, so a measurement voltage Va obtained with the reflected light of projected infrared rays varies owing to the fluctuation of installation in the beginning of the charging and accurate range finding data can not be obtained in this state even when the voltage Va is converted into time data. For the purpose, a transistor Q2 is turned off the set time of the timer T2 later to start the charging of a capacitor C2 with a constant current, and the range finding voltage Va is inputted in terms of time, thereby obtaining the accurate range finding data. |
