PHOTODETECTOR, DIFFRACTION GRATING, OPTICAL PICKUP, AND OPTICAL DISK DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a photodetector, a diffraction grating, an optical pickup, and an optical disk device in which light quantity variation caused by interference and a highly accurate tracking error signal and a focusing error signal can be generated, in an optical pickup mounting two wavelength multi-laser.

SOLUTION: The device is provided with three light receiving area receiving respectively light beams emitted from a laser light source of a first wavelength and branched to three beams and arranged in alignment, and three light receiving area receiving respectively light beams emitted from a laser light source of a second wavelength being longer wavelength than the first wavelength and arranged in alignment. Distance between light receiving area of both sides out of three light receiving area receiving a light beam of the first wavelength is longer than distance between light receiving area of both sides out of three light receiving area receiving a light beam of the second wavelength.

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