| 摘要 |
PURPOSE:To obtain a high C/N in an optical recording medium by a method other than shortening of numerical aperture and a reproduced wavelength of an objective lens system of a reproducer when a recording medium having a high recording density is reproduced and in addition, to obtain a high C/N even when a relatively linear speed to a recording light and a reproducing light is made low. CONSTITUTION:A mask layer 4, an intermediate dielectric layer 5, a recording layer 6 and a reflecting layer 8 are provided on a transparent substrate 2. The layer 6 contains a recording material in which a crystalline structure is varied by emitting a recording light to record information. The layer 4 contains a mask material in which optical transmittance is improved when it is melted. A reduction in a real number part n0 of complex refraction (n0-ik0) of the layer 4 when the material is amorphous or finely crystalline is set to 1.0 or less, and a reduction in an imaginary number part is set to 0.25 to 1.0. |
