| 摘要 |
PURPOSE:To eliminate deterioration with age by adding at least one kind of aluminum oxide and silicon oxide to a composite film and specifying the refractive index thereof to <=215 and >=170. CONSTITUTION:The composite dielectric film 2 composed of the aluminum nitride and silicon nitride as well as the aluminum oxide and silicon oxide is formed by sputtering on the groove side of a grooved PC substrate 1. An NdDyFeCoTi film 3 which is a magneto-optical recording layer is formed thereon and furthermore, the same composite dielectric film 4 as the composite dielectric film 2 is formed thereon. The films are formed under such sputtering conditions under which the refractive index (n) of the composite dielectric films attains <=215 and >=170. The deterioration of the composite dielectric film with age is thereby eliminated for a long period of time. |
