| 摘要 |
PURPOSE:To allow the execution of recording at the uniformized width and edges of pits by specifying the optical parameter relating to a difference between the film thickness in pregroove parts and the film thickness in land parts and forming the pregrooves narrow and deep. CONSTITUTION:When the real number part of the double refractive indices of a light absorption layer is designated as nabs, the film thickness in the pregroove parts of the light absorption layer as dgr, the film thickness in the land parts of the light absorption layer as dln, the wavelength of reproducing light as lambda, and further, 0.12<= C<=0.75 is set, C=nads(dgr-dln)/lambda is specified. The film thickness of the pregrooves 6 formed with pits 11 by the deformation of a substrate 2 or the decomposition, etc., of the dyes of the light absorption layer 3 increases and the film thickness decreases in the right and left land 7 parts. The fine pits 11 having the good edges are formed in this way. |
