Optical pickup apparatus employing nonpolarization beam splitter and quarter wavelength plate

Abstract

An optical pickup apparatus for irradiating a light beam on an optical recording medium for recording or reproduction, including a light source, an objective lens, a nonpolarization beam splitter, a photodetector, and a 1/4 wavelength plate. The objective lens focuses the light beam radiated from the light source on to the recording layer of the optical recording medium. The nonpolarization beam splitter is disposed between the objective lens and the light source and separates the light beam emitted from the light source and the light beam reflected by the recording layer of the optical recording medium. The photodetector receives the beam of light reflected by the recording layer of the optical recording medium which has been separated by the nonpolarization beam splitter and deflected 90.degree. in optical path. The 1/4 wavelength plate is disposed on the path of emission of the light beam emitted from the light source between the nonpolarization beam splitter and the optical recording medium.

Dependencies are inferred from the claim text.