OPTICAL INFORMATION RECORDING MEMBER

摘要

PURPOSE:To prevent the deterioration in signal quality when recording and erasion are repeated by using the different structure of protecting layers at both sides of a thin film recording layer or the different materials for structure between the light incident side and its opposite side. CONSTITUTION:The protecting layers 2 and 4 have different materials or different structures. When laser light is supplied from the side of the layer 2, the larger value of heat escapes toward the layer 2 from thin film recording a layer 3 than the route toward the layer 4 from the layer 3. The difference in temperature is reduced in the thickness direction of the layer 3 and at the same time an excessive rise of temperature is suppressed at the areas close to the interface between the layer 2 at the light incident side and the layer 3. The heat is rather liable to escape to both layers 2 and 4 from the layer 3 and then to stay at the opposite side. Therefore, the difference in temperature is reduced between the light incident side and its opposite side in the thickness direction of the layer 3. Thus the irradiated part reaches entirely a sufficient level of temperature. Thus it is possible to increase the repeating frequency of recording and erasion with no deterioration in signal quality.