| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device having a small loss for light quantity which can be used for various kinds of optical disks. SOLUTION: In the optical pickup device, the light linearly polarized in the polarization direction α from a laser light source 1 is transmitted through a beam splitter 3 and half-wave plates 5, 7 to be converted into a circularly polarized light, which is condensed by object lenses 6, 8 onto recording layers 10, 11 of an optical disk; and the light reflected on the recording layers of the optical disk is transited through the object lens and the quarter-wave plate to be converted into a linearly polarized light in the polarization direction at α+90 deg., with is reflected by the beam splitter 3 and condensed onto a light accepting element 13. In the device, the beam splitter 3 is a polarization beam splitter, and at least two groups of the object lenses and quarter-wave plates are switched over for use according to the kinds of the objective optical disks. |
