| 摘要 |
<p>[Problem] To provide an optical pickup device capable of matching the optical axes of two out of three laser beams using a low-cost diffraction grating while achieving the desired diffraction efficiency. [Solution] An optical pickup device (1) is provided with a diffraction grating (200) on which a BD beam, a DVD beam and a CD beam travelling toward an optical detector (110) are incident. A rectangular-shaped diffraction groove (201) having a single bottom surface is formed in the diffraction grating (200). The diffraction grating (200) is arranged so that the diffraction direction of the diffraction grating (200) is parallel to the alignment direction of the optical axes of the BD beam, the DVD beam and the CD beam. The optical detector (110) is provided with a 4-divided sensor (S1) arranged on the position where the 0 order diffracted light of the BD beam and the +1st order diffracted light of the DVD beam are overlapped, and a 4-divided sensor (S4) arranged on the position onto which the +1st order diffracted light of the CD beam is irradiated.</p> |
