Patent ID: 8054729

Claim:
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 1 and formed between the medium surface and the first information recording surface; a first intermediate layer having a refractive index nr 2 and formed between the first information recording surface and the second information recording surface; and a second intermediate layer having a refractive index nr 3 and formed between the second information recording surface and the third information recording surface, wherein in a case where shape-wise thicknesses tr 1 , tr 2 , and tr 3 of the cover layer, the first intermediate layer, and the second intermediate layer are respectively converted into thicknesses t 1 , t 2 , and t 3 of the respective corresponding layers each having a predetermined refractive index “no”, and in a case where a thickness of a layer having a refractive index nrα is set to trα (satisfying: 1≦α≦n (where α is a positive integer and n is an integer of 3 or more)), a convergence angle of light in the layer having the refractive index nrα is set to θrα (satisfying: 1≦α≦n (where α is a positive integer and n is an integer of 3 or more)), a thickness of the layer having the refractive index “no” is set to tα (satisfying: 1≦α≦n (where α is a positive integer and n is an integer of 3 or more)), and a convergence angle of light in the layer having the refractive index “no” is set to θo, if the thickness trα is converted into the thickness tα based on the following equation, tα=trα (tan(θ rα )/tan(θ o )), the thicknesses t 1 , t 2 , and t 3 satisfy | t 1−( t 2 +t 3)≧1 μm, and a difference between any two values of the thicknesses t 1 , t 2 , and t 3 is set to 1 μm or more in any case.