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Cover glass for watch

A watch and protective cover technology, applied in the field of watch cover glass, can solve the problems of anti-reflection film damage, peeling, surface blur, etc., and achieve the effect of improving wear resistance and hardness

Inactive Publication Date: 2010-08-18
CITIZEN WATCH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the above-mentioned watch is worn for a long time, there is a problem that the surface of the anti-reflection film may be slightly damaged or peeled off, resulting in a blurred surface and making it difficult to see the hands and dial.
[0008] However, the antireflection film disclosed in Patent Document 2 has room for improvement in actual hardness and damage resistance.

Method used

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  • Cover glass for watch
  • Cover glass for watch
  • Cover glass for watch

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0070] The watch cover glass according to Embodiment 1 of the present invention includes a transparent base material having a front surface and a back surface, and an antireflection film laminated on both surfaces of the front surface and the back surface.

[0071] (transparent substrate)

[0072] Examples of the base material include blue plate glass (soda glass), white plate glass, synthetic quartz, sapphire glass, and transparent plastics. Examples of transparent plastics include polycarbonate, methyl methacrylate resin, polystyrene, polyethylene terephthalate, and the like.

[0073] The thickness of the substrate is usually 200 to 4000 μm.

[0074] In addition, in this specification, the front side of the base material refers to the surface exposed to the outside air when the watch cover glass of Embodiment 1 is used for a timepiece; The surface opposite to the dial when the cover glass is used for a watch.

[0075] (anti-reflection film)

[0076] The anti-reflection f...

Embodiment approach 2

[0099] The watch cover glass according to Embodiment 2 of the present invention includes a transparent base material having a front surface and a back surface, and an antireflection film laminated on both of the front surface and the back surface.

[0100] (transparent substrate)

[0101] The substrate used in the second embodiment of the present invention is the same as that in the first embodiment.

[0102] (anti-reflection film)

[0103] The antireflection film used in Embodiment 2 is formed by coating Si from the substrate to the outermost layer. 3 N 4 The film and the mixed film are laminated in this order in four layers alternately, and the outermost layer is the mixed film. That is, the antireflection films on the front and back have the following composition from the substrate side: Si 3 N 4 Membrane / Hybrid Membrane / Si 3 N 4 Membrane / Hybrid Membrane. In addition, the anti-reflection film on the front side can be laminated with a total of 6, 8, 10 or 12 layers o...

Embodiment approach 3

[0115] The watch cover glass according to Embodiment 3 of the present invention includes a transparent base material having a front surface and a back surface, and an antireflection film laminated on the back surface.

[0116] (transparent substrate)

[0117] The substrate used in the third embodiment of the present invention is the same as that in the first embodiment.

[0118] (anti-reflection film)

[0119] The antireflection film used in Embodiment 3 is formed by combining a mixed film with Si from the substrate to the outermost layer. 3 N 4 The film is formed by laminating five layers alternately in this order, and the outermost layer is a mixed film. That is, as shown in FIG. 8 , the antireflection film on the back has the following structure from the substrate side: mixed film 21 / Si 3 N 4 Membrane 22 / Hybrid Membrane 23 / Si 3 N 4 Membrane 24 / Hybrid Membrane 25 . In addition, the anti-reflection film on the back can be laminated with a total of 7, 9 or 11 layers ...

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Abstract

To provide a cover glass for watches which has a high hardness and excellent wearing resistance, is less apt to be marred even in long-term wear, and can retain antireflection properties. The cover glass for watches is characterized in comprising a transparent base and, formed on at least one side thereof, an antireflection film of a multilayer structure comprising a film of an SiO2 / Si3N4 mixture (hereinafter, referred to as SiON film) and an Si3N4 film, and is characterized in that the SiON film has been formed as an outermost layer. Due to the constitution, not only a satisfactory reflection-preventive effect can be obtained, but also the antireflection film has an increased hardness and significantly increased wearing resistance. Consequently, the antireflection film of this cover glass for watches, even in long-term wear, neither suffers fine surface mars nor peels off nor poses a problem, for example, that the fingers and dial become dim due to surface fogging. Furthermore, this cover glass retains antireflection properties.

Description

technical field [0001] The present invention relates to a cover glass for a timepiece, and particularly relates to a cover glass for a timepiece excellent in maintaining the antireflection function over a long period of time and excellent in damage resistance. Background technique [0002] For the cover glass of a watch, blue plate glass (sodium glass), white plate glass, sapphire glass, etc. are used. These cover glasses all have a large reflectance in the visible light region, and are problematic from the viewpoint of the visibility of hands and dials. That is, a watch that checks the time in various environments such as indoors, outdoors, and day and night has a problem that it is difficult to see the time display due to external light or illumination changes, and these external lights are reflected on the surface of the cover glass. [0003] As a solution to the above problems, a method of coating an antireflection film on both surfaces or at least one surface of a cove...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G04B39/00C03C17/34
CPCC03C17/3435G04B39/002C03C2217/734G04B39/006Y10T428/2495Y10T428/24975
Inventor 村田靖高崎康太郎
Owner CITIZEN WATCH CO LTD
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