| 摘要 |
An optical information recording medium comprising a light transmitting substrate (2) having a spiral pregroove (6) formed on its surface, a light absorptive layer (3) of a coloring matter formed on the substrate (2) directly or with other layer interposed therebetween, and a light reflective layer (4) made of a metal film formed on the light absorptive layer (3) directly or with other layer interposed therebetween, wherein DELTA S </= 0.3 wherein DELTA S is the optical phase difference represented by DELTA S = 2dsub{nsub - nabs(1 - dabs/dsub)}/ lambda wherein dsub is the depth of the layer boundary on the substrate side of the light absorptive layer (3) at the portion corresponding to the pregroove (6), dabs is the depth of the layer boundary on the light absorptive layer side of the light reflective layer (4) at the portion corresponding to the pregroove (6), nsub is the real part of the complex refractive index of the substrate and any layer present on the substrate side of the light absorptive layer, nabs is the real part of the complex refractive index of the light absorptive layer (3), and lambda is the wavelength of a laser beam. |
