| 摘要 |
PURPOSE:To raise a humidity resistance by constituting a reflecting film provided on the surface of a base board, of a thin film of titanium or a titanium alloy, or a metallic thin film and a thin film of titanium or a titanium alloy provided on this thin film. CONSTITUTION:A thin film of titanium or a titanium alloy is utilized as a reflecting thin film instead of an aluminum thin film. Or a thin film of titanium or a titanium alloy is provided on a metallic reflecting thin film. For instance, a reflecting film 5 of titanium or a titanium alloy is provided on a disk base board 1, and also on said film a protecting film 4 is provided. Or a thin film 6 of titanium or a titanium alloy is provided on the metallic reflecting thin film 3. When raising a reflection factor, it is better to constitute the metallic reflecting film 3 of an aluminum thin film, and to provide a thin film of titanium or a titanium alloy on this thin film. In case when the aluminum thin film and the titanium thin film are set to 700Angstrom and about 500Angstrom , respectively, a stable humidity resistance can be obtained. |
