| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical multi-layer information recording medium where a recording characteristic is not changed in spite of the change of numerical aperture caused by compensation of a spherical surface aberration which is performed at the position of a recording layer and also in spite of recording without the change of a power density in an optical spot. SOLUTION: The optical multi-layer information recording medium is the medium where at least >=2 recording layers and light transmission layers are alternately laminated and information is recorded and/or played back by the irradiation of collected light beams. Optional two recording layers, i.e., a first depth recording layer being close to the irradiation side of the light beam and a second depth recording layer being far from the irradiation side of the light beam are constituted of a material which satisfies a function with, as parameters, the transmissivity and the absorption rate of the first depth recording layer, the absorption rate of the second depth recording layer, the numerical aperture on the first depth recording layer, the numerical aperture on the second depth recording layer and the transmissivity between the first and the second depth recording layers. |
