| 摘要 |
<p>PURPOSE:To prevent an image intensifier from being troubled owing to the forgetful neglect of switching by detecting the quantity of a visible light beam which passes through a 1st lens and is reflected by a half-mirror by a photodetector and driving a 1st day/night switching mirror and a 2nd day/night switching mirror to specific positions according to the detected quantity of light. CONSTITUTION:Part of light which passes through the 1st lens from the side of an object 1 to be monitored is reflected by the half-mirror 2 and converged on the photodetector 22. The detection signal supplied from the photodetector 22 is inputted to a motor control circuit 23. The detection signal is compared with a previously set target value and the motor control circuit 23 judges whether or not day/night switching is performed. Switching driving motors 24 and 25 operate for the day/night switching according to the judgement, thereby performing the day/night switching automatically. Consequently, the image intensifier 10 is prevented from being troubled owing to the incidence of intense light on the image intensifier due to the neglect of switching.</p> |
