| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device capable of detecting light beams reflected on a second layer stably even when a disk has recording layers of two layers for a sigle-side reading. SOLUTION: The light beams from a semiconductor laser 32 are collimated in a collimating lens 34 and reflected on the plane of polarization of a polarizing beam splitter 36. The reflected light beams are made incident on an objective lens 30 with a quanterwave plate 38 and focused on the first recording layer 14 or the second recording layer 16 of a DVD disk 10 by the objective lens 30. The light beams reflected on the recording layer 16 are returned to the polarizing beam splitter 36 with the objective lens 30 and the quaterwave plate 38 and pass through the plane of polarization of the splitter 36 to be directed to a condensing lens 40. Then, the light beams are converged on a photodetector 42 by the lens 30. |
