TURNING ANGLE DETECTING MECHANISM FOR MIRROR TURNING ACTUATOR

摘要

PURPOSE:To improve the precision by providing a light emitting member which irradiates light to the rear face of the reflection face of a mirror and a light receiving element which receives the reflected light and detecting the angle of turning of the reflection face of the mirror by the output of the light receiving element. CONSTITUTION:A driving mechanism which turnably supports a mirror 1 to turn the mirror, a light emitting element 61 which throws light to the reflection face of the mirror 1, a light receiving element 62 which receives the reflected light, and an angle detecting circuit 7 are provided. The angle of turning of the reflection face of the mirror 1 is detected by the output of the light receiving element 62. That is, the mirror 1 is turned with a shaft in a reflection face 1a as the center, and a control beam is reflected from the center of turning on the rear face of the reflection face 1a. Thus, an influence of the translational oscillation mode or the rotational oscillation mode due to the thickness of the mirror is reduced to detect and track the angle of turning of the mirror with a high precision 0.