Angle detection apparatus, optical signal switch system and information recording and reproduction system

摘要

A reflective surface for detection is provided in an object being detected. Laser light condensed by a condensing lens is emitted from a laser light source and angle detection is performed by performing angle detection of the reflected light. The reflected light is irradiated onto a beam splitter and the optical path thereof is split by an optical path splitting surface to form luminous flux spots on light receiving surfaces of two four section light receivers. Optical path lengths from the reflective surface for detection to the respective light receiving surfaces are changed enabling the angle detection sensitivity to be altered. In an angle detection apparatus, an optical signal switch system, and an information recording and reproduction system, it is possible to make multiple detections of an inclination angle of a detection object using a compact structure. Consequently, improvements in various performances such as apparatus reliability, inclination angle detection precision, and detection range can be achieved.