| 摘要 |
PROBLEM TO BE SOLVED: To eliminate influence of stray light of a return light beam of a main beam with high degree of accuracy in each sub-photodetector. SOLUTION: An optical pickup device is provided with a first optical system in which a return beam of the main beam is projected to a main photodetector 41 and return light beams of two sub-beams are projected to sub-photodetectors 42, 43, sub-photodetectors having the same constitution as the sub-photodetectors 42, 43 and prescribed to the same position relation, a second optical system in which the return light beam of the main beam is converted to a return light beam of which the light intensity distribution is point symmetrical centering around an optical axis for a return light beam of the main beam projected to the sub-photodetectors 42, 43 and shift direction is reverse, and a tracking control part in which a tracking error signal is operated based on respective signals obtained by correcting a signal from the sub-photodetector 42 is corrected by a signal from the sub-photodetector 45 and by correcting a signal from the sub-photodetector 43 by a signal from the sub-photodetector 44. COPYRIGHT: (C)2009,JPO&INPIT
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