Damage-resistant glass articles and method

Patent metadata

Field	Value
Publication number	US-2016167343-A1
Application number	US-201615052446-A
Country	US
Kind code	A1
Filing date	Feb 24, 2016
Priority date	May 14, 2010
Publication date	Jun 16, 2016
Grant date	—

Abstract

A strengthened glass article has opposing first and second compressively stressed surface portions bound to a tensilely stressed core portion, with the first surface portion having a higher level of compressive surface stress than the second surface portion for improved resistance to surface damage, the compressively stressed surface portions being provided by lamination, ion-exchange, thermal tempering, or combinations thereof to control the stress profiles and limit the fracture energies of the articles.

First claim

What is claimed is:

1 . A glass article comprising:
a glass core layer; first and second glass surface layers fused to the glass core layer to form a laminated article, each of the first and second glass surface layers having a lower thermal expansion than the glass core layer; and a stress profile resulting at least partially from subjecting the laminated article to an ion-exchange treatment.

2 . The glass article of claim 1 , wherein at least one of the first or second glass surface layers comprises a surface compression of at least 300 MPa.

3 . The glass article of claim 1 , wherein the glass core layer comprises a tensile stress not exceeding 20 MPa.

4 . The glass article of claim 1 , wherein the thermal expansion of each of the first and second glass surface layers is less than or equal to 52×10 −7 /° C.

5 . The glass article of claim 1 , wherein the thermal expansion of the glass core layer is greater than or equal to 74×10 −7 /° C.

6 . The glass article of claim 1 , further comprising a bending moment M as defined by the expression M=(1+φ(D 1 +D 2 +D 3 )/ρ of substantially zero, wherein D 1 , D 2 and D 3 correspond, respectively, to bending rigidities of the first glass surface layer, the glass core layer, and the second glass surface layer, and wherein ρ represents a common radius of curvature of the glass article.

7 . The glass article of claim 1 , wherein each of the first and second glass surface layers comprises a compressively stressed surface portion of the glass article, and the glass core layer comprises a tensilely stressed core portion of the glass article.

8 . The glass article of claim 1 , wherein one of the first or second glass surface layers comprises a higher surface compression than the other of the first or second glass surface layers.

9 . The glass article of claim 1 , wherein the first glass surface layer comprises a different composition than the second glass surface layer.

10 . The glass article of claim 1 , wherein the first glass surface layer comprises a different thermal expansion than the second glass surface layer.

11 . The glass article of claim 1 , wherein the first glass surface layer comprises a different thickness than the second glass surface layer.

12 . The glass article of claim 1 , wherein the thermal expansion of each of the glass core layer, the first glass surface layer, and the second glass surface layer is the thermal expansion at a set point of the respective layer.

13 . The glass article of claim 1 , wherein:
at least one of the first or second glass surface layers comprises a surface compression of at least 300 MPa; the thermal expansion of each of the first and second glass surface layers is less than or equal to 52×10 −7 /° C.; and the thermal expansion of the glass core layer is greater than or equal to 74×10 −7 /° C.

14 . A glass article comprising:
a glass core layer; and first and second glass surface layers laminated to the glass core layer, each of the first and second glass surface layers having a lower thermal expansion than the glass core layer; and wherein at least a portion of a stress profile of the glass article comprises an error function profile.

15 . The glass article of claim 14 , wherein at least one of the first or second glass surface layers comprises a surface compression of at least 300 MPa.

16 . The glass article of claim 14 , wherein the glass core layer comprises a tensile stress not exceeding 20 MPa.

17 . The glass article of claim 14 , wherein the thermal expansion of each of the first and second glass surface layers is less than or equal to 52×10 −7 /° C.

18 . The glass article of claim 14 , wherein the thermal expansion of the glass core layer is greater than or equal to 74×10 −7 /° C.

19 . The glass article of claim 14 , wherein the first glass surface layer comprises at least one of a different composition, a different thermal expansion, or a different thickness than the second glass surface layer.

20 . A method comprising:
laminating first and second glass surface layers to a glass core layer to form a laminated glass sheet having opposing first and second surfaces with first and second compressive stresses, respectively; and subjecting the laminated glass sheet to an ion exchange treatment to modify at least one of the first or second compressive stresses.

Assignees

• Corning Inc

Inventors

• Gulati Suresh Thakordas
• Suman Balram

Classifications

• C03B27/065

  Stresses, e.g. patterns, values or formulae · CPC title

• B32B2307/558

  Impact strength, toughness · CPC title

• C03B27/0413

  Stresses, e.g. patterns, values or formulae for flat or bent glass sheets · CPC title

• Y10T428/2495

  Thickness [relative or absolute] · CPC title

• Y10T156/10

  Methods of surface bonding and/or assembly therefor · CPC title