| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that a focusing control operation is adversely affected by an unnecessary light reflected on a signal recording layer when reproducing a signal recorded in the signal recording layer. SOLUTION: The optical pickup device is provided with an objective lens 8 for condensing a laser beam on the signal recording layer of an optical disk, a diffraction grating 2 for receiving the laser beam and generating a main beam which is a 0-order light and sub-beams which are±1-order lights, a sub-beam receiving part constituted of a 4-division sensor for receiving a sub-beam reflected from the signal recording layer and generating a tracking error signal, and a photodetector 10 constituted of a 4-division sensor for receiving a main beam reflected from the signal recording layer and generating a reproducing signal and a focus error signal. The light receiving area of the sub-beam receiving part is formed smaller than that of the main beam receiving part. COPYRIGHT: (C)2009,JPO&INPIT
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