Patent ID: 7298690

Claim:
An optical recording medium having grooves formed along recording tracks and being applied with light having a predetermined wavelength λ for performing recording and/or reproduction, as the grooves, a first groove, a second groove, and a third groove shallower than the first groove and the second groove formed so as to be arranged adjacently, the medium having six recording tracks of the first to third grooves and three lands between the respective first to third grooves, wherein, assuming that a refractive index of a medium from a light entrance surface to the grooves is n, a depth coefficient of the first and second grooves is x, x×n/λ is a phase depth X of the first and second grooves, a depth coefficient of the third groove is y, and y×n/λ is a phase depth Y of the third groove, the depth coefficient x of the first and second grooves and the depth coefficient y of the third groove satisfy the following expressions (1) and (2), Y ≦16.126 X 5 −123.24 X 4 +371.85 X 3 −544.35 X 2 +409.06 X −119.33 (1) Y ≧1.8941 X 4 −11.776 X 3 +27.83 X 2 −29.495 X +11.887 (2).