Cover glass and glass laminate

Patent metadata

Field	Value
Publication number	US-2018215659-A1
Application number	US-201815874357-A
Country	US
Kind code	A1
Filing date	Jan 18, 2018
Priority date	Jan 31, 2017
Publication date	Aug 2, 2018
Grant date	—

Abstract

The present invention provides a cover glass and a glass laminate which are reduced in warpage, and have excellent scratch resistance, low reflecting properties and excellent optical properties. According to the present invention, a cover glass and a glass laminate which are reduced in glass warpage, retain the effect of scratch resistance, and have low reflecting properties and excellent optical properties can be provided by alternately superposing a film including a high-refractive-index material and a film including a low-refractive-index material, in given amounts.

First claim

1 . A cover glass comprising a glass sheet and an inorganic film superposed on at least one surface of the glass sheet,
wherein the glass sheet has a thickness of 1 mm or less, the inorganic film is a multilayer film including six or more layers formed by alternately superposing a film including a high-refractive-index material having a refractive index at 632-nm wavelength of 1.80 or higher and a film including a low-refractive-index material having a refractive index at the wavelength of less than 1.80, the films including the high-refractive-index material and the films including the low-refractive-index material each having a single-film thickness of 5 nm to 250 nm, the six or more superposed layers having a total thickness of 850 nm to 6,000 nm, and a warpage change between a warpage amount of the glass sheet by itself and a warpage amount of the cover glass including the superposed inorganic film is 30% or less.

2 . The cover glass according to claim 1 , wherein the high-refractive-index material is silicon nitride.

3 . The cover glass according to claim 1 , wherein the low-refractive-index material is silicon oxide.

4 . The cover glass according to claim 1 , wherein the single-film thickness of the film including the low-refractive-index material is smaller than the single-film thickness of the film including the high-refractive-index material.

5 . The cover glass according to claim 1 , wherein a film including the high-refractive-index material has been superposed over an outermost surface of the glass sheet, with a film including the low-refractive-index material interposed therebetween.

6 . The cover glass according to claim 1 , wherein an overall thickness of the inorganic film is 850 nm to 3,000 nm.

7 . The cover glass according to claim 1 , wherein the glass sheet is a chemically strengthened glass sheet having a compressive stress layer as a surface layer.

8 . The cover glass according to claim 1 , further comprising an antifouling film disposed on a surface of the inorganic film.

9 . A cover glass comprising a glass sheet and an inorganic film superposed on at least one surface of the glass sheet,
wherein the glass sheet has a thickness of 1 mm or less, the inorganic film includes six or more layers formed by alternately superposing a film including a high-refractive-index material having a refractive index at 632-nm wavelength of 1.80 or higher and a film including a low-refractive-index material having a refractive index at the wavelength of less than 1.80, the films including the high-refractive-index material and the films including the low-refractive-index material each having a single-film thickness of 5 nm to 250 nm, the inorganic film having an overall thickness of 850 nm to 6,000 nm, and when the cover glass is placed on a horizontal platen so that one main surface of the cover glass is in contact with the platen and warpage amounts of the cover glass, which are amounts in which four corners of the cover glass have lifted from the platen, are measured with a gap gauge at 20° C., then an average value of the warpage amounts is 400 μm or less.

10 . The cover glass according to claim 9 , wherein the high-refractive-index material is silicon nitride.

11 . The cover glass according to claim 9 , wherein the low-refractive-index material is silicon oxide.

12 . The cover glass according to claim 9 , wherein the single-film thickness of the film including the low-refractive-index material is smaller than the single-film thickness of the film including the high-refractive-index material.

13 . The cover glass according to claim 9 , wherein a film including the high-refractive-index material has been superposed over an outermost surface of the glass sheet, with a film including the low-refractive-index material interposed therebetween.

14 . The cover glass according to claim 9 , wherein the overall thickness of the inorganic film is 850 nm to 3,000 nm.

15 . The cover glass according to claim 9 , wherein the glass sheet is a chemically strengthened glass sheet having a compressive stress layer as a surface layer.

16 . The cover glass according to claim 9 , further comprising an antifouling film disposed on a surface of the inorganic film.

17 . A glass laminate comprising a glass sheet and an inorganic film superposed on at least one surface of the glass sheet,
wherein the inorganic film includes six or more layers formed by alternately superposing a film including a high-refractive-index material having a refractive index at 632-nm wavelength of 1.80 or higher and a film including a low-refractive-index material having a refractive index at the wavelength of less than 1.80, the films including the high-refractive-index material and the films including the low-refractive-index material each having a single-film thickness of 5 nm to 250 nm, the inorganic film having an overall thickness of 850 nm to 6,000 nm, and an absolute value of product obtained by multiplying the overall thickness of the inorganic film by an overall stress value of the inorganic film is 220×10 3 nm·MPa or less.

18 . The glass laminate according to claim 17 , wherein an absolute value of a stress value of the film including the high-refractive-index material is smaller than an absolute value of a stress value of the film including the low-refractive-index material.

19 . The glass laminate according to claim 17 , wherein the stress value of the film including the high-refractive-index material is larger than the stress value of the film including the low-refractive-index material.

20 . The glass laminate according to claim 17 , wherein the absolute value of the product obtained by multiplying the overall thickness of the inorganic film by the overall stress value of the inorganic film is 100×10 3 nm·MPa or less.

21 . The glass laminate according to claim 17 , wherein the films including the high-refractive-index material each have a single-film stress value, an absolute value of which is 30-250 MPa.

22 . The glass laminate according to claim 17 , wherein the films including the low-refractive-index material each have a single-film stress value, an absolute value of which is 100-300 MPa.

23 . A glass laminate comprising a glass sheet and an inorganic film superposed on at least one surface of the glass sheet,
wherein the inorganic film includes six or more layers formed by alternately superposing a film including a high-refractive-index material having a refractive index at 632-nm wavelength of 1.80 or higher and a film including a low-refractive-index material having a refractive index at the wavelength of less than 1.80, the films including the high-refractive-index material and the films including the low-refractive-index material each having a single-film thickness of 5 nm to 250 nm, the inorganic film having an overall thickness of 850 nm to 6,000 nm, and an absolute value of an overall stress value of the inorganic film is 80 MPa or less.

24 . The glass laminate according to claim 23 , wherein an absolute value of a stress value of the film including the high-refractive-index material is smaller than an absolute value of a stress value of the film including the low-refractive-index material.

25 . The glass laminate according to claim 23 , wherein the stress value of the film including the high-refractive-index material is larger than the stress value of the film including the low-refractive-index mater

Assignees

• Asahi Glass Co Ltd

Inventors

• Maeshige Kazunobu
• Aomine Nobutaka
• Okawa Hiroyuki
• Tamai Kiyoshi
• Onoda Hitoshi
• Sano Makoto
• Kobayashi Yusuke

Classifications

• B32B2315/08

  Glass · CPC title

• C03C17/3435 Primary

  comprising a nitride, oxynitride, boronitride or carbonitride · CPC title

• B32B17/10137

  Chemical strengthening · CPC title

• B32B2255/20

  Inorganic coating · CPC title

• C03C17/02

  with glass (C03C17/34, C03C17/44 take precedence) · CPC title