Patent ID: 8535775
Filing Date: 2013-09-17
Classification: G11B,Y10T

Abstract:
1. An optical recording medium having a translucent recording/reproducing functional layer which comprises at least a first protective layer, a second protective layer, a recording layer, a third protective layer, a reflective layer and a fourth protective layer in this order from the incidence side of laser light, wherein the second protective layer and the fourth protective layer are made of a material having the same constituting elements, wherein the refractive index of the second protective layer is higher by at least 0.3 than the refractive index of the first protective layer, and wherein, when the film thickness of the second protective layer is set as D2, the film thickness of the fourth protective layer is set as D4, and the reflectivity before recording when the laser light is focused on the recoding layer is set as R, the positive and negative of increasing rates d(R)/d(D2) and d(R)/d(D4) relative to the film thickness of R are inverse, wherein the second protective layer and the fourth protective layer are made of a material containing ZnS.