Optical information reproducing device forming light spot on photo-detector with major axis along push-pull signal detection

摘要

An optical information reproducing device for reading informations recorded on the opto-magnetic recording medium is disclosed. The device comprises a first beam splitter for separating an inward path from an outward path of the light and a second beam splitter having a plane-parallel plate for separating the separated return light into two light fluxes including light flux with at least astigmatism, the first beam splitter having transmittivity and reflectance factor for the polarization component in the direction perpendicular to the linear polarization direction of the incident light being about 100%, the photodetector for receiving light flux with astigmatism separated from the second beam splitter being arranged in such a manner that the major axis of the ellipsoidal spot formed on the photodetector due to astigmatism becomes the push-pull signal direction.