| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium wherein spherical aberration is further suppressed with respect to a protective layer consisting of a plurality of layers as compared with conventional ones and normal recording and/or reproduction can be performed and to provide an optical information recording/reproducing method and an optical information recording/reproducing device. <P>SOLUTION: The optical information recording medium is provided in which the ranges of a refractive index and a thickness of a protective layer in the case where the protective layer consists of a plurality of layers is newly specified and the refractive index and the thickness of the protective layer are determined in the ranges, thereby ensuring that even if a variation in the thickness of the protective layer to ±3 μm is tolerated, spherical aberration in the optical information recording medium can be suppressed substantially within 30 mλrms. Thereby, the problem is solved that in a large numerical aperture and in a short wavelength, large spherical aberration is caused due to the different refractive indices of the plurality of layers which constitute the protective layer and when a variation in the thickness of the protective layer is further added, the spherical aberration exceeds the acceptable range, resulting in failure to perform normal recording and reproduction. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
