METHOD FOR MANUFACTURING STRENGTHENED GLASS SUBSTRATE, AND STRENGTHENED GLASS SUBSTRATE

• US 20130101798A1
• Filed: 08/22/2012
• Published: 04/25/2013
• Est. Priority Date: 08/23/2011
• Status: Abandoned Application

• Current Assignee: Hoya Corporation
• Original Assignee: Hoya Corporation
• Inventors: HASHIMOTO, Kazuaki
• Application Number:
  US13/591,552
• Publication Number:
  US 20130101798A1
• Time in Patent Office: Days
• US Class Current: 428/157
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/085 containing an oxide of a divalent metal
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: Y10T 428/24488 Differential nonuniformity at margin
• CPC Class Codes: Y10T 428/315 Surface modified glass [e.g., tempered, strengthened, etc.]

Abstract

A method for manufacturing a strengthened glass substrate includes: a chemical strengthening step of chemically strengthening a plate glass material by ion-exchange; and a shaping step of cutting the chemically strengthened plate glass material by etching. In the chemical strengthening step, the ion-exchange is performed to satisfy the condition of 7≦T_ave≦50 [MPa], when the thickness of the plate glass material is denoted by t [μm], the thickness of the compressive stress layer by d [μm], the maximum compressive stress value of the compressive stress layer by F [MPa], the compressive stress integrated value of the compressive stress layer by X [MPa·μm], the thickness of the tensile stress layer by t₂ [μm], the average tensile stress value of the tensile stress layer by T_ave [MPa], and the relationships represented by equations X=F×d, t₂=t−2d and T_ave=X/t₂ are satisfied.

Claims

1. A method for manufacturing a strengthened glass substrate comprising:

a chemical strengthening step of performing ion-exchange on a plate glass material to form a compressive stress layer in a surface layer of the plate glass material while forming a tensile stress layer in a deep portion other than the surface layer; and

a shaping step of performing etching on the plate glass material which has been subjected to the chemical strengthening step to cut the plate glass material into small-sized glass substrates, wherein;

the plate glass material is prepared, consisting of alumino-silicate glass containing an alkali metal oxide; and

in the chemical strengthening step, the ion-exchange is performed to generate such a tensile stress that the plate glass material is not damaged by the etching.

2. The method for manufacturing a strengthened glass substrate according to claim 1, wherein in the chemical strengthening step, the ion-exchange is performed to satisfy the condition of

7≦

T_ave<

50 [MPa]

when the thickness of the plate glass material is denoted by t [μ

m], the thickness of the compressive stress layer is denoted by d [μ

m], the maximum compressive stress value of the compressive stress layer is denoted by F [MPa], the compressive stress integrated value of the compressive stress layer is denoted by X [MPa·

μ

m], the thickness of the tensile stress layer is denoted by t₂ [μ

m], the average tensile stress value of the tensile stress layer is denoted by T_ave [MPa], and the relationships represented by the equations X=F×

d, t₂=t−

2d and T_ave X/t₂ are satisfied.

3. The method for manufacturing a strengthened glass substrate according to claim 1, further comprising, after the chemical strengthening step and before the shaping step, a decorating layer formation step of forming one or more decorating layers on at least one of the surfaces of the plate glass material which has been subjected to the ion-exchange,

wherein in the shaping step performed after the decorating layer formation step, the plate glass material having the decorating layer formed thereon is cut by the etching.

4. The method for manufacturing a strengthened glass substrate according to claim 3, wherein the decorating layer formation step comprises a printing operation of performing printing on the major surface of the plate glass material with its end face being held.

5. The method for manufacturing a strengthened glass substrate according to claim 3, wherein the decorating layer formation step comprises an operation of forming a conductive layer and a transparent conductive layer on the major surface of the plate glass material.

6. The method for manufacturing a strengthened glass substrate according to claim 1, wherein as the plate glass material, used is a glass containing 50 to 75% by weight of SiO₂, 5 to 20% by weight of Al₂O₃, and at least one alkali metal oxide selected from Li₂O, Na₂O and K₂O.

7. The method for manufacturing a strengthened glass substrate according to claim 6, wherein as the plate glass material, used is a glass containing 8% by weight or more of Na₂O and 8% by weight or less (including 0) of CaO.

8. The method for manufacturing a strengthened glass substrate according to claim 1, wherein the strengthened glass substrate is a glass substrate for use as a cover glass for electronic equipment.

9. A strengthened glass substrate consisting of an alumino-silicate glass containing an alkali metal oxide, having a compressive stress layer in a surface layer and a tensile stress layer in a deep portion, wherein:

the strengthened glass substrate is subjected to ion-exchange satisfying the condition of

7≦

T_ave<

50 [MPa]

when the thickness of the alumino-silicate glass is denoted by t [μ

m], the thickness of the compressive stress layer is denoted by d [μ

m], the maximum compressive stress value of the compressive stress layer is denoted by F [MPa], the compressive stress integrated value of the compressive stress layer is denoted by X [MPa·

μ

m], the thickness of the tensile stress layer is denoted by t₂ [μ

m], the average tensile stress value of the tensile stress layer is denoted by T_ave [MPa], and the relationships represented by the equations X=F×

d, t₂=t−

2d and T_ave=X/t₂ are satisfied; and

the strengthened glass substrate has an end face which has been subjected to etching.

10. The strengthened glass substrate according to claim 9, wherein the end face of the strengthened glass substrate has a pair of curved faces projecting outward in a thickness direction of the major surface and an apex projecting from the curved faces outward in a planar direction of the glass base.

11. The strengthened glass substrate according to claim 9, wherein no compressive stress layer is formed at least in a partial region of the end face of the strengthened glass substrate.

12. The strengthened glass substrate according to claim 9, wherein the alumino-silicate glass is a glass containing, as glass components, 50 to 75% by weight of SiO₂, 5 to 20% by weight of Al₂O₃, and at least one alkali metal oxide selected from Li₂O, Na₂O and K₂O.

13. The strengthened glass substrate according to claim 12, wherein the alumino-silicate glass is a glass containing 8% by weight or more of Na₂O and 8% by weight or less (including 0) of CaO.

14. The strengthened glass substrate according to claim 9, wherein the strengthened glass substrate is a glass substrate for use as a cover glass for electronic equipment.