| 摘要 |
PROBLEM TO BE SOLVED: To solve conventional problems or restrictions in attaining miniaturization and low cost for pickups or optical recording and reproducing devices, in which a tilt angle is detected by mounting, around an optical pickup, a tilt sensor constituted of light emitting diodes, photodetectors, etc. SOLUTION: When tilt occurs between an optical axis 25 and an optical disk 21, with an objective lens 22 in a tracking-controlled state, a signal corresponding to the tilt is outputted to a differential amplifier 66. In addition, the amplitude of a pit signal varies by the tilt; hence, tilt detection is made possible without a tilt sensor by observing these signals through a control circuit 29. Further, in a sample servo type tracking control, no DC offset occurs by tilt; therefore, stability of a tracking control system against tilt can be improved by merely compensating, with the use of a variable gain amplifier 67, the reduction in the pit amplitude caused by tilt. |
