Optical recording medium

Abstract

Abstract PURPOSE:To increase the redundancy of the conditions for the film formation of a protective layer and to improve the yield of the film formation by specifying the material of the protective layer and the layer thickness of the optical recording medium formed by providing a recording layer with which a reversible phase change is generated when irradiated with a light beam and the protective layer covering this layer on a transparent substrate. CONSTITUTION:Resins, such as polycarbonate, PMMA and PET or glass, etc., are used for the substrate material and the resin materials are more preferable in terms of a recording sensitivity. Materials, such as GeTe, Ge-Te alloy, In-Sb alloy, In-Se alloy and Sb-Te alloy, with which the phase change between the crystal and amorphous phases is possible are used as the phase change material used for the recording layer. The recording layer is put in an unrecording state when the layer is amorphous. This part is crystallized to execute recording. The protective layer is then deposited on the recording layer by a sputtering method or the like. Ti, Zr or the alloy thereof is used for the material of this time and the film thereof is formed to >=40mm. No influence is exerted to the reflectivity of the medium in spite of the minor fluctuation in the film thickness of the protective layer if the medium is formed in such a manner.

Inventors

• 👤 Yutaka Ueda
• 👤 裕 上田
• 👤 Toru Yashiro
• 👤 徹 八代

Bibliographic Details