TEMPERED GLASS PLATE AND PRODUCTION METHOD FOR TEMPERED GLASS PLATE

• US 20190330104A1
• Filed: 06/13/2017
• Published: 10/31/2019
• Est. Priority Date: 06/17/2016
• Status: Active Grant

• Current Assignee: Nippon Electric Glass Company Limited
• Original Assignee: Nippon Electric Glass Company Limited
• Inventors: KAJIOKA, Toshiyuki, FUKADA, Mutsumu, KINOSHITA, Kiyotaka
• Granted Patent: US 11,104,606 B2
• Time in Patent Office: Days
• CPC Class Codes: C03C 17/02 with glass C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 17/245 by deposition from the vapour phase
• CPC Class Codes: C03C 17/25 by deposition from the liquid phase
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2218/154 by sputtering
• CPC Class Codes: C03C 2218/34 Masking
• CPC Class Codes: C03C 2218/365 Coating different sides of a glass substrate
• CPC Class Codes: C03C 3/085 containing an oxide of a divalent metal
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 4/18 for ion-sensitive glass

Abstract

A tempered glass sheet (G4) includes a compressive stress layer having a compressive stress on a main surface, and a tensile stress layer having a tensile stress in an inside. The tempered glass sheet (G4) includes: a highly anisotropic stress region (Qa) which is arranged in at least part of an end edge portion, and which has a stress showing anisotropy in a plane parallel to the main surface; and a low anisotropic stress region (Qb) which is arranged on a center side in a main surface direction so as to be adjacent to the highly anisotropic stress region (Qa), and which has a stress showing lower anisotropy than the highly anisotropic stress region (Qa) in the same plane parallel to the main surface.

Claims

1. A tempered glass sheet including a compressive stress layer having a compressive stress on a main surface, and a tensile stress layer having a tensile stress in an inside,

the tempered glass sheet comprising:

a highly anisotropic stress region which is arranged in at least part of an end edge portion, and which has a stress showing anisotropy in a plane parallel to the main surface; and

a low anisotropic stress region which is arranged on a center side in a main surface direction so as to be adjacent to the highly anisotropic stress region, and which has a stress showing lower anisotropy than the highly anisotropic stress region in the same plane parallel to the main surface.

2. The tempered glass sheet according to claim 1, wherein the highly anisotropic stress region has a stress showing anisotropy in a direction along a contour shape of the end edge portion.

3. The tempered glass sheet according to claim 2, wherein, when the compressive stress in a first direction along the contour shape as seen in a sheet thickness direction is defined as a first compressive stress, and the compressive stress in a second direction perpendicular to the first direction in the plane parallel to the main surface is defined as a second compressive stress, the first compressive stress is larger than the second compressive stress in the compressive stress layer in the highly anisotropic stress region.

4. The tempered glass sheet according to claim 3,

wherein the first compressive stress in the highly anisotropic stress region is 700 MPa or more, and

wherein a difference obtained by subtracting the second compressive stress from the first compressive stress in the highly anisotropic stress region is 15 MPa or more.

5. The tempered glass sheet according to claim 3, wherein, when the first compressive stress and the second compressive stress are measured at arbitrary observation points equidistant from a boundary between the highly anisotropic stress region and the low anisotropic stress region in the plane parallel to the main surface, a difference obtained by subtracting the second compressive stress measured at the observation point in the low anisotropic stress region from the first compressive stress measured at the same observation point is smaller than a difference obtained by subtracting the second compressive stress measured at the observation point in the highly anisotropic stress region from the first compressive stress measured at the same observation point.

6. The tempered glass sheet according to claim 3, wherein a difference between the first compressive stress and the second compressive stress in the low anisotropic stress region is 40 MPa or less.

7. The tempered glass sheet according to claim 3, wherein, at an arbitrary point in the highly anisotropic stress region as seen in a sheet thickness direction, a depth of layer from the main surface at which the first compressive stress becomes zero is larger than a depth of layer from the main surface at which the second compressive stress becomes zero.

8. The tempered glass sheet according to claim 1, wherein, when a retardation in a sheet thickness direction in the highly anisotropic stress region is defined as R (nm), an optical elastic constant of the tempered glass sheet is defined as a (nm/cm/MPa), and a sheet thickness of the tempered glass sheet is defined as t (cm), the following expression (1) is satisfied

R/α

t≥

10 

 

(1).

9. The tempered glass sheet according to claim 1,

wherein the highly anisotropic stress region is arranged along an entirety of the end edge portion, and

wherein the low anisotropic stress region is surrounded by the highly anisotropic stress region.

10. The tempered glass sheet according to claim 1, wherein a boundary between the highly anisotropic stress region and the low anisotropic stress region is positioned at 8 mm or less from an end portion of the tempered glass sheet as seen in a sheet thickness direction.

11. The tempered glass sheet according to claim 1,

wherein the tempered glass sheet as seen in a sheet thickness direction has a contour shape including a linear side portion,

wherein the side portion has a length of from 10 mm to 5,000 mm,

wherein the tempered glass sheet has a sheet thickness of from 0.1 mm to 2.0 mm, and

wherein the highly anisotropic stress region is arranged in a belt shape along the side portion.

12. The tempered glass sheet according to claim 1, wherein a depth of layer of the compressive stress layer in the highly anisotropic stress region is larger than a depth of layer of the compressive stress layer in the low anisotropic stress region.

13. The tempered glass sheet according to claim 1, wherein the tensile stress in the highly anisotropic stress region is larger than the tensile stress in the low anisotropic stress region.

14. The tempered glass sheet according to claim 1, wherein directions of optical main axes in the highly anisotropic stress region and the low anisotropic stress region are different from each other at a boundary between the highly anisotropic stress region and the low anisotropic stress region.

15. The tempered glass sheet according to claim 14, wherein the compressive stress layer in the highly anisotropic stress region as seen in a sheet thickness direction has an optical main axis in a direction along a contour shape of the end edge portion.

16. The tempered glass sheet according to claim 14, wherein an optical main axis of the compressive stress layer in the highly anisotropic stress region and an optical main axis of the compressive stress layer in the low anisotropic stress region as seen in a sheet thickness direction form an angle of 45 degrees or more.

17. A method of producing a tempered glass sheet including chemically tempering a glass sheet to be tempered through ion exchange,

the method comprising:

a film forming step of forming an ion exchange suppressing film configured to suppress the ion exchange in a film formation region on a main surface of the glass sheet to be tempered excluding at least part of an end edge portion of the glass sheet to be tempered to provide a glass sheet with a film; and

a tempering step of chemically tempering the glass sheet with a film by an ion exchange method to provide a tempered glass sheet.

18. The method of producing a tempered glass sheet according to claim 17,

wherein the glass sheet to be tempered as seen in a sheet thickness direction has a contour shape including a linear side portion;

and

wherein, when a region on the main surface other than the film formation region is defined as a non-film formation region, the non-film formation region is set to a belt shape along the side portion.

19. The method of producing a tempered glass sheet according to claim 17, wherein, when a region on the main surface other than the film formation region is defined as a non-film formation region, the non-film formation region is set along an entirety of the end edge portion of the glass sheet to be tempered so as to surround the film formation region.

20. The method of producing a tempered glass sheet according to claim 17, wherein, when a region on the main surface other than the film formation region is defined as a non-film formation region, a boundary between the film formation region and the non-film formation region is set to a position of 8 mm or less from an end portion of the glass sheet to be tempered as seen in a sheet thickness direction.

21. The method of producing a tempered glass sheet according to claim 17, further comprising, after the tempering step, a removal step of removing the ion exchange suppressing film.