Damage-resistant glass articles and method

Patent metadata

Field	Value
Publication number	US-10843439-B2
Application number	US-201615052446-A
Country	US
Kind code	B2
Filing date	Feb 24, 2016
Priority date	May 14, 2010
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

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
an asymmetric stress profile resulting at least partially from subjecting the laminated article to an ion-exchange treatment at outer surfaces of the laminated article; and
a bending moment M as defined by the expression M=(1+ρ)(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.

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 , 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.

7. 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.

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

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

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

11. 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.

12. 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.

13. The glass article of claim 1 , 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.

Assignees

• Corning Inc

Inventors

• Gulati Suresh Thakordas
• Suman Balram

Classifications

• B32B37/0015

  to avoid warp or curl · CPC title

• B32B2457/208

  Touch screens · CPC title

• B32B37/144

  using layers with different mechanical or chemical conditions or properties, e.g. layers with different thermal shrinkage, layers under tension during bonding (constructional features for tensioning B32B38/1825) · CPC title

• C03B23/203

  Uniting glass sheets (C03B23/24 takes precedence) · CPC title

• Y10T428/2495

  Thickness [relative or absolute] · CPC title