| 摘要 |
PURPOSE:To prevent the oxidation of a recording layer and to assure the long- term stability of an optical disk by forming the 1st protective layer consisting of a specific composite layer, the recording layer and the 2nd protective layer on a transparent substrate provided with guide tracks. CONSTITUTION:The dielectric layer 5 contg. a rare earth metal and a passive state metallic layer 6 having <=30Angstrom thickness are formed on the transparent substrate 1 to form the 1st protective layer. The recording layer 3 and the 2nd protective layer 4 are formed thereon. All the free oxygen generated at the time of forming the dielectric layer of the 1st layer and the free radicals and moisture, etc., diffused from the substrate 1 are trapped and fixed by the rare earth element in the dielectric layer 5 and therefore, the deterioration of the recording layer 3 by the same is prevented. The diffusion of the free oxygen, free radicals and moisture is further prevented by the passive state metallic layer 6. Any among Ti, Cr, Ta, Al, and Nb is suitable as the passive state metal.
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