| 摘要 |
PURPOSE:To enable always stable positional adjustment by detecting the incident position of light in a one-dimensional direction by a photoelectric convertion means which reads said position to know the position of an optical element and controlling an optical element by a position adjusting means based on said detection. CONSTITUTION:An arithmetic circuit 16 moves roughly a pulse motor 7 in an open loop by as much as a prescribed number of pulses via a driver 17. The mirror 5 driven by said motor is moved within the prescribed range near the position (a), i.e., within the range wherein the reflected light R from the mirror 5 can be detected by a sensor 15. The signals (h) and (i) of the sensor 15 are thereafter subjected to precise position control so that the mirror 5 is stabilized in the normal position (a). |
