INFORMATION RECORDING MEDIUM AND DISK DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an information recording medium with recording and reproducing characteristics enhanced by optimizing a groove shape of a substrate.

SOLUTION: The information recording medium has two or more recording layers, wherein a track pitch of the recording layer is in the range of 250 to 500 nm and a half-value width of the groove of the substrate is in the range of 47.5 to 72.5% of the track pitch.

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