| 摘要 |
PROBLEM TO BE SOLVED: To rapidly discriminate a recording layer without a sensor mechanism at a disk loading time, etc., by discriminating a first recording layer and a second recording layer having a track pitch narrower than the same of the first recording layer according to whether or not a traverse signal is obtained in the state in which a disk surface is irradiated with a laser beam of resolution corresponding to the first recording layer to be focused nearly. SOLUTION: An optical disk 1 has a CD layer recording the CD data as the recording layer and/or an HD layer recording the HD data having higher definition than the CD data. At a recording layer discrimination operational time, a CD reproducing mode for reproducing the CD layer is set, and an objective lens 34 is moved from the farthest position of the optical disk 1 surface to the nearest position. At this time, it is discriminated that when the traverse signal (intensity modulation as tracking error signal TE) is obtained in the position equivalent to a focus drawing range, it is the CD layer, and when the traverse signal isn't obtained, it is the HD layer.
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