| 摘要 |
The optical pickup device ( 1 ) includes a two-wavelength compound light source ( 2 ) that is capable of emitting two light beams having different wavelengths and a light source ( 3 ) emitting a single wavelength light beam. The laser beam emitted from the latter single wavelength light source ( 3 ) has an optical path length different from that of the laser beam emitted from the former two-wavelength compound light source ( 2 ). The optical pickup device ( 1 ) is equipped with a hologram element ( 8 ). One of the surfaces ( 8 a) of the hologram element (8) has a lens effect for compensating the difference between the optical path lengths of the laser beams emitted from the single wavelength light source ( 3 ) and the two-wavelength compound light source ( 2 ). The other surface ( 8 b) of the hologram element ( 8 ) has an optical control function for enabling generation of a servo signal.
|
