| 摘要 |
PURPOSE:To improve the ability to prohibit the passage of moisture, etc., and to suppress the deterioration with time by forming a protective film consisting of plural metal oxide films having high stability or a protective film consisting of a metal oxide film and metallic film on the outside surface of a reflecting film. CONSTITUTION:A 1st dielectric film 2 consisting of Si3N4, a magnetic recording medium 3 consisting of a TbFeCo system, a 2nd dielectric film 4 consisting of Si3N4, and the reflecting film 5 consisting of Al, are formed on a transparent substrate 1 formed with rugged groove patterns 1a.... The 1st protective film 6 consisting of a Ta film (metallic film) 8 and a Ta2O5 film (metal oxide film) 9 is formed on the reflecting film 5 and further the 2nd protective film 7 is formed. The protective film consisting of the plural metal oxides having the high stability or the protective film consisting of the metal oxide film and the metallic film is added in such a manner, by which the capacity to prohibit the passage of the moisture, etc., is improved and, therefore, the deterioration with age is suppressed. |
