Patent ID: 8081551
Filing Date: 2011-12-20
Classification: G11B

Abstract:
1. An optical recording medium having a plurality of information recording surfaces, the optical recording medium comprising: a first information recording surface closest to a medium surface of the optical recording medium where light is incident; a second information recording surface second closest to the medium surface; a third information recording surface third closest to the medium surface; a cover layer having a refractive index nr a first intermediate layer having a refractive index nr a second intermediate layer having a refractive index nr in the case where shape-wise thicknesses tr a defocus amount with respect to a layer having a refractive index nrα and a thickness trα (satisfying: 1≦α≦n (where α is a positive integer and n is an integer of 3 or more)), and a defocus amount with respect to a layer having the refractive index “no” and a thickness tα (satisfying: 1≦α≦n (where α is a positive integer and n is an integer of 3 or more)) are equal to each other, and the thicknesses t