| 摘要 |
PURPOSE:To maintain the best state as a light transmission system at all times by controlling and adjusting the angle of each reflecting mirror according to the detection result of a four-division photodetector which detects the optical axis or spot position of an adjusting light beam reflected by the reflecting mirror. CONSTITUTION:When the reflecting surface of a 1st mirror 12 slants from a reference slanting position, the beam spot shifts in position on the detection surface of the 4-division photodetector 28 and detection outputs of its four division detector do not coincide with one another. Those output detection signals are inputted to a control driving device 34. The control driving device 34 finds the slanting direction of the optical axis of the adjusting light beam L or the slanting direction of the reflecting surface of a 1st mirror 12 from the four detection signals from the 4-division photodetector 28 and drives the 1st mirror 12 so that the reflecting surface slants to the reference position. Consequently, the optical axis of the adjusting light beam L reflected by the 1st mirror 12 is held invariably; constant and 2nd and 3rd mirrors 14 and 16 are also controlled similarly. |
