Position change detector

Abstract

Abstract PURPOSE:To detect changes in the position of a moving mirror satisfactorily, by arranging a first detection means for detecting relative positional deviation between an optical member and a moving body and a second detection means for detecting the inclination of a reflecting surface in comparison of positional deviations detected. CONSTITUTION:An MPU 54 calculates the capacitance difference between capacitors Cya and Cyb and determines the inclination value theta0 corresponding to the difference from a table stored in a memory 56. Moreover, the MPU 54 determines the positional deviation beta0 corresponding to the difference from the initial value of the capacitance of the capacitors Cya and Cyb in the same way. The inclination value theta0 and the positional deviation value beta0 are outputted to an arithmetic circuit 20 as data LY indicating variations. Then, the arithmetic circuit 20 calculates what position a laser flux LA is irradiated in the direction (x) on a reflecting surface 12A of a moving mirror 12. The y-way deviation DELTAy of the laser flux LA is determined at an incident point on the reflecting surface 12A.

Inventors

• 👤 Kunihiro Nakano
• 👤 中野　邦博

Bibliographic Details