Optical head and information recording/reproducing apparatus

摘要

By using one embodiment of an invention, a diffraction pattern of a diffraction element or hologram polarization element (24) to guide a reflected laser beam divided into a predetermined number is suitably combined as one body in a photodetector (26), and an optical head unit (11) is easily designed to obtain a focus error signal, a track error signal, a correction track error signal (in a system with a lens shift), and a reproducing signal (RF) from a laser beam reflected on an optical disc. Therefore, when reproducing information from a recording medium of optional standard, it is possible to provide an optical head unit and optical disc apparatus which provides a stable reproducing signal regardless of the standards of recording media.