| 摘要 |
The present invention is to provide a practically usable, recordable or rewritable optical information recording medium having a pair of recording layers and a recording and reproducing apparatus for the medium. The recording medium has a pair of recording layer structures on a substrate so as to sandwich a resin intermediate layer, and a recording beam and a reproducing beam are irradiated to two recording layer structures. The pair of recording layer structures respectively have a different track pitch, and the ratio of difference in the track pitch defined by Expression 1 is +0.03 to +0.15, <?in-line-formulae description="In-line Formulae" end="lead"?>(T2-T1)/T1 Expression 1<?in-line-formulae description="In-line Formulae" end="tail"?> T1 represents a track pitch of the recording layer structure disposed on the laser beam irradiation side, and T2 represents a track pitch of the recording layer structure disposed on the inner side.
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