OPTICAL RECORDING MEDIUM, OPTICAL HEAD, AND OPTICAL REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical recording medium, an optical head and an optical reproducing device capable of realizing stable access even when a count omission is generated.

SOLUTION: Reflection films 106 for servo are disposed at both side edges of cores 104 and reflectance of reflection films 106 for servo of the 10k-th (k=a natural number) data layer and dummy layer from an upper end part are made higher than those of the other data layers. Thereby, the amplitude of a servo signal at the time when the 10k-th data layer and dummy layer are scanned with a beam is made larger then that at the time when the other data layers are scanned. When accessing, the amplitude of the servo signal is monitored to detect the scanning timing of the 10k-th data layer and propriety of the count value at this time is judged. If it is inappropriate, the count value according to the 10k-th's is set to a counter. Entrance of the beam to the dummy layers is detected by the amplitude of the servo signal and the access is ended depending the detection.

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