WATCH COVER GLASS
First Claim
1. A watch cover glass comprising a transparent substrate having a front surface and a back surface and, provided on at least one surface of the substrate, an antireflection film obtainable by laminating a SiO2 and Si3N4 mixed film and a Si3N4 film alternately one after another in the total of 4 layers or 5 or more layers and having the SiO2 and Si3N4 mixed film in the outermost layer.
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Accused Products
Abstract
The present invention provides a watch cover glass having high hardness and excellent abrasion, and also having flaw resistance and antireflection function even after being used for a long period of time.
[Means for Solving]
The watch cover glass of the present invention comprises a transparent substrate and, provided on at least one surface of the substrate, an antireflection film having a lamination structure that a SiO2 and Si3N4 mixed film (hereinafter, referred to as SiON film) and a Si3N4 film are laminated and the outermost layer is the SiON film. According to the lamination structure, the proper antireflection effect can be obtained, the hardness of the antireflection film is increased and the abrasion resistance is remarkably increased. As a result, the watch cover glass provided by the present invention has properties such that even after being used for a long period of time, the surface of the antireflection film is not finely flawed and is not peeled off, and it hardly occurs that the hands or dial plate are invisible due to surface mist and the antireflection function can be maintained.
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Citations
19 Claims
- 1. A watch cover glass comprising a transparent substrate having a front surface and a back surface and, provided on at least one surface of the substrate, an antireflection film obtainable by laminating a SiO2 and Si3N4 mixed film and a Si3N4 film alternately one after another in the total of 4 layers or 5 or more layers and having the SiO2 and Si3N4 mixed film in the outermost layer.
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10. A process for producing a watch cover glass comprising a transparent substrate having a front surface and a back surface and, provided on at least one surface thereof, an antireflection film, which process comprises:
an antireflection film-forming step of laminating a SiO2 and Si3N4 mixed film and a Si3N4 film alternately one after another in the total of 4 layers or 5 or more layers by a reactive sputtering method to prepare an antireflection film having the SiO2 and Si3N4 -mixed film in the outermost layer. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
Specification