Pioneer Electronic Corporation

Hitoshi Furuhata

Shigeru Takaya

Masufumi Asada

Aki Terajima

There is provided an optical pickup which comprises a light source, an objective lens for converging a beam from the light source onto an optical disc, a diffraction grating for passing a beam returning from the optical disc, a photo-detector for receiving returning beams passing through the diffraction grating. The diffraction grating is divided into two areas, each area including alternatively arranged first diffraction grating pattern and second diffraction grating pattern.

Optical pickup

An optical pickup is adapted to be operated in accordance with a tracking error signal obtained by a push-pull method. The pickup has a photodetector including a pair of detector elements disposed side by side. An astigmatizer is disposed on an axis of a light beam reflected from an optical disc for producing an astigmatic beam. The photodetector is positioned outside a point where a spot of the astigmatic beam becomes a circular shape, and a boundary line between the two detector elements is disposed on a line along which the spot moves in a tracking operation.

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Saitama, Japan

Hitoshi Furuhata