| 摘要 |
PROBLEM TO BE SOLVED: To prevent misdiscrimination of the type of an optical disk by accurately detecting a wobbling signal at low costs even when the balance of the quadripartite photodetector of an optical pickup is shifted in the radial direction of the optical disk. SOLUTION: A laser beam is converged on the recording surface of an optical disk, the reflected light of the laser beam from the recording surface of the optical disk is received to output a detection signal from a photodetection means, the converging position of the laser beam is shifted in the radial direction of the optical disk, the incident position of a laser beam made incident on the photodetection means is shifted, and the type of the optical disk is discriminated based on the frequency of the detection signal output from the photodetection means. COPYRIGHT: (C)2006,JPO&NCIPI
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