| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size of an optical pickup head without raising the manufacturing cost by providing an optical means directing light beams having first and second wavelengths which are to be emitted from first and second light sources to an optical disk and moreover providing a photodetecting device detecting reflected light beams having the first and second wavelengths which are reflected on the optical disk and another optical means directing the reflected light beams to the photodetecting means. SOLUTION: First and second light beams 4, 10 to be emitted from first and second light sources 2, 3 are directed to an optical disk 1 by the optical means. The optical means has a beam splitter 5 directing the light beams 4,10 to a collimating lens 6 while reflecting the first beam 4 and transmitting the second light beam 10, the collimating lens 6, a reflecting mirror 7 and an objective lens 8. First and second light beams 4, 10 which are reflected on the optical disk 1 are directed to a photodetecting means 11 by another optical means, which has the objective lens 8, the reflecting mirror 7 and the collimating lens 6 which are common to the optical means. Thus, most components constituting the optical means and the another optical means can be made common. |
