Patent ID: 7943223

Claim:
An optical recording medium, comprising: a substrate; a first information layer provided on a laser beam incident surface side of the substrate; and at least one translucent information layer provided on the laser beam incident surface side being located farther away from the substrate than the first information layer, the translucent information layer being configured to include a recording film comprising a phase change material Sb x Ge y In z containing Sb as a main component, Ge, and In in an atomic ratio of x:y:z, 5≦y≦15 and 4≦z≦15 being satisfied, the recording film being rewritable through phase change between a crystalline state and an amorphous state, the phase change being caused by using an optical system with λ/NA≦500 nm, where NA is a numerical aperture of an objective lens and λ is a wavelength of a laser beam, wherein the translucent information layer is configured to include a heat sink layer, a dielectric layer, an interface layer, the recording film, and a reflection layer which are formed in that order from the laser beam incident surface side, the recording film further comprises Te in an atomic ratio of a, provided that x+y+z+a=100 and 4≦a≦15 are satisfied, the dielectric layer is formed of a mixture of ZnS and SiO 2 , the molar ratio of ZnS to SiO 2 being 50:50 to 95:5, the interface layer is formed of a ZrO 2 —Cr 2 O 3 film, a thickness of the ZrO 2 —Cr 2 O 3 film being 2 nm or more and 10 nm or less, when a compositional ratio of the ZrO 2 —Cr 2 O 3 film is given by ZrO 2 :CrO 3 =B:C (mol %), 20≦B≦90, 10≦C≦80, and B+C=100 are satisfied, the ZrO 2 is stabilized ZrO 2 containing Y 2 O 3 and when a compositional ratio of ZrO 2 and Y 2 O 3 in the stabilized ZrO 2 is given by ZrO 2 :Y 2 O 3 =(100−b):b (mol %), 2≦b≦10 is satisfied.