| 摘要 |
PURPOSE:To allow the execution of good recording with a wide power window at the time of recording even if the power of the recording light is strong by specifying an optical parameter or the value of the ratio of the film thicknesses between lands and pregrooves to a prescribed value or below. CONSTITUTION:The real number of the double refractive indices of a light absorption layer is designated as nabs, the film thickness in the parts of the lands positioned on the right and left of the pregrooves as dln, the real number part of the double refractive indices of the substrate as nsb, and the wavelength of the reproducing light as lambda, and Ls<0.3 is set when Ls=nabs.nsub.lambda is set. Then, the difference in the recording sensitivity between the parts of the lands 7 and the parts of the pregrooves 6 is increased. The absorbed heat is confined within the pregrooves 6 in this way and the fine pits 11 having the good edges are formed in this way. |
