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| Reflecting mirror |
A reflecting mirror which is composed of a reflecting silver layer formed on a surface of a glass base body and a protective layer being made of alloy consisting of copper and tin being formed on said reflecting silver layer. Since the reflecting layer is protected by a protective layer, this reflecting mirror has corrosion resistance.
Inventors:
Nishida, Keiziro (Kanagawa, JA)
Itoh, Susumu (Tokyo, JA)
Konno, Kathuhiro (Kanuma, JA)
Itoh, Susumu (Tokyo, JA)
Konno, Kathuhiro (Kanuma, JA)
The present invention relates to a reflecting mirror in which a protective layer having corrosion resistance is formed on a reflecting silver layer.
In a conventional reflecting mirror a reflecting silver layer is formed on a glass base body and a protective layer consisting of copper is formed on said reflecting layer, wherein a coated layer is formed on said protective layer.
However, such reflecting mirror can not endure a long period of use either in a place of high temperature and high humidity or at a place of coldness. The reason therefor is that a protection afforded by copper does not sufficiently perform its role. For example, when a conventional reflecting mirror is subjected to an endurance test under an environment of a temperature of 60° C and a humidity of 95 percent, or when it is subjected to an endurance test of such temperature-humidity cycle as having one cycle of 2 hours with a temperature of 60° C and a humidity of 70 percent and 2 hours with -30° C, such damages will take place as corrosion, etc. on a reflecting silver layer. In this case, the copper foil in the protective layer is also affected without fail. In other words when the copper in the protective layer is affected, a metal reflecting layer is also damaged.
The object of the present invention is to provide a silver reflecting mirror having sufficient corrosion resistance.
For that end, the reflecting mirror of the present invention is formed by alloy consisting of copper and tin. The protective alloy layer is composed of 30 to 70 percent copper and 70 to 30 percent tin.
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