发明授权
US07706220B2 Photodetector, diffraction grating, optical pickup and optical disc apparatus 有权
光电检测器,衍射光栅,光学拾取器和光盘装置

Photodetector, diffraction grating, optical pickup and optical disc apparatus
摘要:
The present invention provides a photodetector capable of generating highly accurate tracking and focusing error signals free of variations in light quantity caused by interference, in an optical pickup with a two-wavelength multilaser. The photodetector comprises first three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a first wavelength and second three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a second wavelength longer than the first wavelength. The distance between both-end light receiving areas out of the first three light receiving areas is longer than the distance between both-end light receiving areas out of the second three light receiving areas.
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