| 摘要 |
PURPOSE:To obtain the optical information recording medium of a veneer structure having high sensitivity and high C/N by providing an under coating layer consisting of a thermally softening material between a substrate and a recording layer and selectively setting the refractive indices and film thicknesses of the under coating layer and the recording layer. CONSTITUTION:The under coating layer 7 consisting of the thermally softening material is provided between the substrate 2 and the recording layer 3. The layer 7 is set at the refractive index smaller than the refractive index of the substrate 2 and at the film thickness at which the max. reflectivity is obtd. near the wavelength of recording and reproducing light. The layer 3 is set at the refractive index larger than the refractive index of the layer 7 and smaller than the refractive index of a protective film 6 and at the film thickness at which the max. reflectivity is obtd. near the wavelength of the recording and reproducing light. The reflectivity of the layer 3 is, therefore, improved and the deterioration by the reproducing light is decreased. Since the thermally softening material is used for the layer 7, the recording is executed by the deformation formed at the boundary of the layers 3, 7. Multireflection interferences are thus broken and the contrast and the C/N are improved. The recording medium having the high sensitivity and the simple structure is obtd. in this way. |
