| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device precisely detecting the tilt of an optical information recording medium and properly correcting it. SOLUTION: The optical pickup device 1 divides outgoing luminous flux of a semiconductor laser 6 of a light emission part 2 into zero-dimentional, one-dimentional and -one-dimentional luminous flux by a grating 7 to emit them to a light introduction part 3. The light introduction part 3 converges and irradiates the incident luminous flux on an optical disk 5 as three light spots through its objective lens 12, and reflects the reflection light of three light spots reflected by the optical disk 5 to a signal detection part 4 by its polarizing beam splitter 9, and the signal detection part 4 makes the incident light into parallel luminous flux having astigmatism to make them respectively incident on three light receiving parts of a photodetector 15. When the optical disk 5 is tilted for the objective lens 12, focus deviation occurs in the light spots of both side light receiving parts, and the tilt of the optical disk 5 is detected by a difference between the focus error signals of the light receiving parts. |
