| 摘要 |
PURPOSE:To contrive miniaturization of the subject device in lighter weight at low cost by diffracting or refracting reflected light of a recording medium with a grating and a reflecting surface, receiving the light with two photodetectors and detecting track error and focus error signals. CONSTITUTION:The reflected light from a magneto-optical disk is made incident upon the grating 24 of an optical path separating means 22 and separated into zero-th light T and 1st light K in orthogonal polarization directional components. The zero-th light T is reflected by the reflecting surface 25 and refracted at a prescribed angle of refraction to go out to the exterior, while the 1st light K is reflected by the reflecting surface 25 and refracted to go out to the exterior. Then, the 1st light K is made incident upon a bisected 1st photodetector 27 to detect the track error signal, while astigmatism is generated by the zero-th light T and is made incident upon tetrasected 2nd photodetector 28 to detect the focus error signal. By this method, the number of parts are reduced, and the miniaturization and light weight are achieved, and also the production is simplified, reducing the cost. |
