| 摘要 |
<P>PROBLEM TO BE SOLVED: To adjust the position of a diffraction grating to satisfy required levels of visual field characteristics in each wavelength. <P>SOLUTION: The optical pickup device includes: a laser light source including first and second light-emitting points for laser lights of first and second wavelengths which are disposed at positions deviating in a direction optically corresponding to an optical-disc-tracking direction, and selectively emitting a laser beam of the first or second wavelength; a diffraction grating including a plurality of periodic structures which are joined to be different in phase from each other in the direction and each of which includes a recess and projection repeated in a direction optically corresponding to an optical-disc-tangential direction, the diffraction grating being configured to generate main and sub luminous fluxes from the laser light; and a holder to hold the diffraction grating to be movable in the direction corresponding to the tracking direction. <P>COPYRIGHT: (C)2010,JPO&INPIT |
