| 摘要 |
PURPOSE:To obtain a medium which satisfies the push-pull value, reflectance and modulation degree specified by CD standards by specifying an optical phase difference and film thickness of a light-absorbing layer in a pregroove. CONSTITUTION:The pregrooves 6 and the light-absorbing layer are formed so as to satisfy the relations expressed by formulae II and III. In these formulae, dsub is the distance from the interface 8 between the light-absorbing layer 3 and a substrate 2 in an land area 7 formed on both sides of the pregroove 6 to the bottom of the interface 8 in the pregroove 6, and dabs is the distance from the interface 9 between the light-absorbing layer 3 and light-reflecting layer 4 in the land area 7 to the bottom of the interface 9 in the pregroove 6. nsub is the real part of the complex refractive index of the substrate 2, nabs is the real part of the complex refractive index of the light-absorbing layer 3, is the wavelength of reproducing light L2, DELTAS expressed by formula I is the optical phase difference in reproducing light L2 reflected from the light- reflecting layer 4 in the pregroove 6 and in the land area 7, and dgr is film thickness of the light-absorbing layer 3 in the pregroove 6. |
