Patent ID: 7539121

Claim:
An optical recording medium comprising: a first substrate having first pits on one face thereof; a first reflective layer formed on the face bearing the first pits of the first substrate in a manner so as to reflect lands and recesses of the first pits; a second substrate formed on the first reflective layer, with second pits being formed on a face on the side opposite to the first reflective layer; a second reflective layer formed on the face bearing the second pits of the second substrate in a manner so as to reflect lands and recesses of the second pits; and a cover layer formed on the second reflective layer, wherein a first pit depth d 1 , which is a difference between lands and recesses of the first reflective layer, a wavelength λ of signal-reproducing laser light and a refractive index n 1 of the second substrate satisfy the following relational expressions, λ/(5 n 1 )≦ d 1 ≦λ/(3 n 1 ) and d 1 ≠λ/(4 n 1 ), wherein a second pit depth d 2 , which is a difference between lands and recesses of the second reflective layer, the wavelength λ of signal-reproducing laser light and a refractive index n 2 of the cover layer satisfy the following relational expressions, λ/(5 n 2 )≦ d 2 ≦λ/(3 n 2 ) and d 2 ≠λ(4 n 2 ), wherein the first pits of the first substrate and the second pits of the second substrate are formed by a combination of concave-shaped pits and convex-shaped pits or a combination of convex-shaped pits and concave-shaped pits, wherein the first pit depth d 1 is a difference between lands and recesses of the first reflective layer, and the second pit depth d 2 is a difference between lands and recesses of the second reflective layer, and wherein the first pit depth d 1 and the second pit depth d 2 satisfy the following relational expressions, with respect to the refractive index n 1 of the second substrate, the refractive index n 2 of the cover layer and the wavelength λ of signal-reproducing laser light, 4n 1 d 1 <λ<4n 2 d 2 .