| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device in which track offset caused in a tracking control using a DDP method can be canceled with a simple configuration and the assembling and adjusting of a device can be simplified. SOLUTION: A diffracting lattice is formed so that an area ratio (S1/S0) in which SO is beam area of +1st or -1st order diffracted light irradiated on the diffraction lattice being an optical member provided with an optical pickup and S1 is area of the diffraction lattice giving phase difference for +1st order or -1st order diffracted light is made a value within the prescribed range, further, an insertion position of the diffraction lattice for a beam of light emitted from a light source is adjusted. Thereby, an amplitude ratio (SPP/MPP) of a push-pull signal SPP based on a sub-beam being±1st order diffracted light and a push-pull signal MPP based on a main beam being zero-order diffracted light is reduced, and quantity of causing track offset can be reduced. COPYRIGHT: (C)2004,JPO
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