Optical pickup device and optical disc apparatus using the same

Abstract

An optical pickup device and an optical disc apparatus which is capable to reduce variation of a detected signal due to unnecessary beam and detect a signal with high quality are provided. Amplification of sup PP signals necessary to produce a tracking error signal by a DPP method can be realized by an amplification factor smaller than a spectral radio of main and sub beams by the following structure. The optical pickup device includes an optical element having an area in which part of beam is diffracted and light shielding zones or insensitive zones having predetermined width are formed on center division lines in the light receiving planes of sub beams of the optical detector. The shape of a diffraction area is optimized to the shift amount of objective lens. The width of the light shielding zones or insensitive zones is optimized from the shift amount of objective lens and the shape of the diffraction area. With such structure, it is possible to suppress interferential disturbance component due to unnecessary light produced in sub PP signals from being amplified by an amplifier and the tracking error signal having less waveform fluctuation can be detected stably and satisfactorily even upon reproduction/recording of a multi-layered disc.

Dependencies are inferred from the claim text.