Protective layer for optical information recording medium

摘要

A protective layer which is applied to rewritable optical information recording medium comprising a substrate and a photosensitive thin film. When exposed to optical energy, the thin layer is capable of undergoing a reversible phase change by which an optical reflectivity is changed between two states. The protective layer is inhibiting the thermal damages of the substrate during light irradiation and also controlling thermal and optical boundary conditions. The protective layer is made of the mixture of mutually solid insoluble materials. The typical choice of the mixture of small crystalline grains of ZnS and noncrystalline SiO2.