| 摘要 |
PROBLEM TO BE SOLVED: To detect surely a desired recording layer in a dual-layer disk. SOLUTION: In a optical disk device 1 performing recording or reproducing of information for an optical disk 100 constituted by laminating successively a first recording layer, a second recording layer, and a cover layer, a focal point of a light beam is approached to the optical disk 100 from a cover layer side, when after a signal level of a focus error signal FE exceeds a positive focus error threshold value and becomes less than it, or when after the signal level becomes less than a negative focus error threshold value and exceeds it, it is discriminated that the focal point of the light beam is approached to the recording layer, also after detection of the recording layer, the focal point of the light beam is continued to approach to the optical disk 100, when the recording layer is not detected again during re-detection period, it is discriminated that a recording layer detected last is the first recording layer. COPYRIGHT: (C)2006,JPO&NCIPI
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