Glass articles exhibiting improved fracture performance

Patent metadata

Field	Value
Publication number	US-9701569-B2
Application number	US-201615214650-A
Country	US
Kind code	B2
Filing date	Jul 20, 2016
Priority date	Jul 21, 2015
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

Embodiments of this disclosure pertain to a strengthened glass article including a first surface and a second surface opposing the first surface defining a thickness (t) of about less than about 1.1 mm, a compressive stress layer extending from the first surface to a depth of compression (DOC) of about 0.1·t or greater, such that when the glass article fracture, it breaks into a plurality of fragments having an aspect ratio of about 5 or less. In some embodiments, the glass article exhibits an equibiaxial flexural strength of about 20 kgf or greater, after being abraded with 90-grit SiC particles at a pressure of 25 psi for 5 seconds. Devices incorporating the glass articles described herein and methods for making the same are also disclosed.

First claim

What is claimed is:

1. A strengthened glass article comprising:
a first surface and a second surface opposing the first surface defining a thickness (t) of about 3 mm or less;
a compressive stress layer extending from the first surface to a depth of compression (DOC) of greater than 0.16·t as measured by scattered light polariscope, the compressive stress layer comprising a surface compressive stress of 400 MPa or greater, as measured by a combination of scattered light polariscope and surface stress meter; and
a maximum central tension that is 50 MPa or greater as measured by scattered light polariscope,
wherein, after the glass article fractures according to a Frangibility Test, the glass article includes a plurality of fragments, wherein at least 90% of the plurality of fragments have an aspect ratio of about 5 or less.

2. The strengthened glass article of claim 1 , wherein the glass article fractures into the plurality of fragments in 1 second or less, as measured by the Frangibility Test.

3. The strengthened glass article of claim 1 , wherein at least 80% of the plurality of fragments have a maximum dimension that is less than or equal to 3·t.

4. The strengthened glass article of claim 1 , wherein at least 50% of plurality of fragments comprises an aspect ratio of 2 or less.

5. The strengthened glass article of claim 1 , wherein at least 50% of the plurality of fragments comprises a volume of less than or equal to about 10 mm 3 .

6. The strengthened glass article of claim 1 , wherein the plurality of fragments comprises an ejected portion of fragments, wherein the ejected portion of fragments comprises 10% or less of the plurality of fragments.

7. The strengthened glass article of claim 1 , wherein the glass article comprises a first weight prior to fracture and the wherein the plurality of fragments comprises an ejected portion of fragments and a non-ejected portion of fragments, the non-ejected portion of fragments having a second weight, and the difference between the first weight and the second weight is 1% of the first weight.

8. The strengthened glass article of claim 1 , wherein the probability of the glass article fracturing into the plurality of fragments within 1 second or less, as measured by a Frangibility Test, is 99% or greater.

9. The strengthened glass article of claim 1 , wherein the glass article comprises a stored tensile energy of 20 J/m 2 or greater.

10. The strengthened glass article of claim 1 , wherein the ratio of the maximum central tension to surface compressive stress is in the range from about 0.1 to about 1.

11. The strengthened glass article of claim 10 , wherein the maximum central tension is 100 MPa/√(t/1 mm) or greater (in units of MPa), wherein t is in mm.

12. The strengthened glass article of claim 1 , wherein the glass article comprises an alkali aluminosilicate glass, alkali containing borosilicate glass, an alkali aluminophosphosilicate glass or alkali aluminoborosilicate glass.

13. The strengthened glass article of claim 1 , wherein the glass article is disposed on a containment layer.

14. The strengthened glass article of claim 1 , further comprising:
a CT region of the stress profile, wherein the CT region is defined by the equation
Stress( x )=MaxCT−(((MaxCT·( n+ 1))/0.5 n )·|( x/t )−0.5| n ),

wherein MaxCT is the maximum CT value and is provided as a positive value in units of MPa, x is position along the thickness (t) in micrometers, and n is between 1.5 and 5.

15. A strengthened glass article comprising:
a first surface and a second surface opposing the first surface defining a thickness (t) of about 3 mm or less;
a compressive stress layer extending from the first surface to a depth of compression (DOC) of greater than 0.2·t as measured by scattered light polariscope, wherein the surface compressive stress is 250 MPa or greater, as measured by a combination of scattered light polariscope and surface stress meter;
a maximum central tension of 85 MPa or more as measured by scattered light polariscope; and
wherein, after the glass article fractures according to a Frangibility Test, the glass article includes a plurality of fragments, wherein at least 90% of the plurality of fragments have an aspect ratio of about 5 or less.

16. The strengthened glass article of claim 15 , further comprising:
a CT region of the stress profile, wherein the CT region is defined by the equation
Stress( x )=MaxCT−(((MaxCT·( n+ 1))/0.5 n )·|( x/t )−0.5| n ),

wherein MaxCT is the maximum CT value and is provided as a positive value in units of MPa, x is position along the thickness (t) in micrometers, and n is between 1.5 and 5.

17. A strengthened glass article comprising:
a first surface and a second surface opposing the first surface defining a thickness (t) of about 3 mm or less;
a compressive stress layer extending from the first surface to a depth of compression (DOC) of greater than about 0.15·t as measured by scattered light polariscope, the compressive stress layer comprising a surface compressive stress of 400 MPa or greater, as measured by a combination of scattered light polariscope and surface stress meter; and
a maximum central tension (CT) of about 50 MPa or greater as measured by scattered light polariscope,
wherein the glass article exhibits a load to failure of about 10 kgf or greater, after being abraded with 90-grit SiC particles at a pressure of 25 psi for 5 seconds.

18. The strengthened glass article of claim 17 , wherein the glass article comprises a stored tensile energy of 20 J/m 2 or greater.

19. The strengthened glass article of claim 17 , wherein the ratio of the maximum central tension to surface compressive stress is in the range from about 0.1 to about 1.

20. The strengthened glass article of claim 19 , wherein the maximum central tension (CT) is M 85 MPa or greater.

21. The strengthened glass article of claim 17 , wherein the DOC comprises about 0.2t or greater.

22. The strengthened glass article of claim 17 , wherein the glass article is adhered to a substrate.

23. The strengthened glass article of claim 17 , further comprising:
a CT region of the stress profile, wherein the CT region is defined by the equation
Stress( x )=MaxCT−(((MaxCT·( n+ 1))/0.5 n )·|( x/t )−0.5| n ),

wherein MaxCT is the maximum CT value and is provided as a positive value in units of MPa, x is position along the thickness (t) in micrometers, and n is between 1.5 and 5.

24. The strengthened glass article of claim 17 , wherein t is 0.4 mm or more.

25. A consumer electronic product comprising:
a housing having a front surface;
electrical components provided at least partially internal to the housing, the electrical components including at least a controller, a memory, and a display; and
a cover glass disposed at the front surface of the housing and over the display, or disposed as a back cover, the cover glass comprising a strengthened glass article,
wherein the strengthened glass article comprises:
a first surface and a second surface opposing the first surface defining a thickness (t) of about 3 mm or less;
a compressive stress layer extending from the first surface to a depth of compression (DOC) of greater than about 0.17 t as measured by scattered light polariscope, the compressive stress layer comprising a surface compressive stress of 200 MPa or more as measured by a combination of scattered light polariscope and surface stress meter; and

Assignees

• Corning Inc

Inventors

• Demartino Steven Edward
• Fabian Michelle Dawn
• Kohli Jeffrey Todd
• Lyon Jennifer Lynn
• Smith Charlene Marie
• Tang Zhongzhi

Classifications

• H05K5/03

  Covers · CPC title

• B32B17/10018

  comprising only one glass sheet · CPC title

• C03C3/085

  containing an oxide of a divalent metal · CPC title

• C03C3/097 Primary

  containing phosphorus, niobium or tantalum · CPC title

• C03C3/093

  containing zinc or zirconium · CPC title