STRENGTHENED GLASS WITH DEEP DEPTH OF COMPRESSION

• US 20150239776A1
• Filed: 10/31/2014
• Published: 08/27/2015
• Est. Priority Date: 02/24/2014
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Amin, Jaymin, Egboiyi, Benedict Osobomen, Pesansky, Jonathan David, Reiman, Kevin Barry, Roussev, Rostislav Vatchev, Strines, Brian Paul
• Granted Patent: US 9,517,968 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C03C 21/00 Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 2204/00 Glasses, glazes or enamels with special properties
• CPC Class Codes: C03C 3/04 containing silica
• 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 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: C03C 3/095 containing rare earths
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: C03C 4/18 for ion-sensitive glass
• CPC Class Codes: G06F 1/1637 Details related to the display arrangement, including those related to the mounting of the display in the housing
• CPC Class Codes: G06F 2200/1634 Integrated protective display lid, e.g. for touch-sensitive display in handheld computer
• CPC Class Codes: H04B 1/3827 Portable transceivers
• CPC Class Codes: Y10T 428/315 Surface modified glass [e.g., tempered, strengthened, etc.]

Abstract

Chemically strengthened glass articles having at least one deep compressive layer extending from a surface of the article to a depth of at least about 45 μm within the article are provided. In one embodiment, the compressive stress profile includes a single linear segment extending from the surface to the depth of compression DOC. Alternatively, the compressive stress profile includes two linear portions: the first portion extending from the surface to a relatively shallow depth and having a steep slope; and a second portion extending from the shallow depth to the depth of compression. The strengthened glass has a 60% survival rate when dropped from a height of 80 cm in an inverted ball drop test and an equibiaxial flexural strength of at least 10 kgf as determined by abraded ring-on-ring testing. Methods of achieving such stress profiles are also described.

Claims

1. A glass article, the glass article having a thickness t and a compressive layer having a compressive stress CS of in a range from about 500 MPa up to about 1200 MPa at a surface of the glass article, wherein:

a. the compressive layer extends from the surface to a depth of compression DOC, wherein DOC≧

0.1·

t when t<

0.5 mm and DOC≧

50 μ

m when t≧

0.5 mm, and wherein the compressive layer has a compressive stress profile; and

b. the compressive stress profile comprises;

i. a first portion b extending from the surface to a depth d_b and having a slope m_b, wherein 3 μ

m≦

d_b≦

15 μ

m and −

40 MPa/μ

m≧

m_a≧

−

200 MPa/μ

m; and

ii. a second portion c extending from d_b to the depth of compression DOC and having a slope m_c, wherein −

2 MPa/μ

m≧

m_c≧

−

8 MPa/μ

m.

2. The glass article of claim 1, wherein −

40 MPa/μ

m≧

m_b≧

−

120 MPa/μ

m.

3. The glass article of claim 1, wherein thickness t is in a range from about 0.15 mm up to about 2.0 mm.

4. The glass article of claim 1, wherein the glass article comprises an alkali aluminosilicate glass.

5. The glass article of claim 4, wherein the alkali aluminosilicate glass further comprises up to about 10 mol % Li₂O.

6. The glass article of claim 1, wherein the glass article has at least about a 60% survival rate when subjected to an inverted ball drop test from a height of about 80 cm onto an abrasive material disposed on the surface of the glass.

7. The glass article of claim 1, wherein the glass article has an equibiaxial flexural strength in a range from about 10 kgf up to about 50 kgf as determined by abraded ring-on-ring testing.

8. The glass article of claim 1, wherein DOC≧

0.11·

t when t<

0.5 mm and 55 μ

m≦

DOC≦

100 μ

m when t≧

0.5 mm.

9. A glass article, the glass article having a thickness t and a compressive region having a compressive stress CS in a range from about 150 MPa to about 400 MPa at a surface of the glass article, wherein:

a. the compressive region extends from the surface to a depth of compression DOC, wherein DOC≧

0.1·

t when t<

0.5 mm and DOC≧

50 μ

m when t≧

0.5 mm, and wherein the compressive layer has a compressive stress profile; and

b. the compressive stress profile has a linear portion a extending from the surface to a depth d_a and a slope m_a, wherein the depth d_a is equal to the depth of compression and −

2 MPa/μ

m≧

m_a≧

−

8 MPa/μ

m.

10. The glass article of claim 9, wherein −

3 MPa/μ

m≧

m_a≧

−

6 MPa/μ

m.

11. The glass article of claim 9, wherein the thickness t is in a range from about 0.15 mm up to about 2.0 mm.

12. The glass article of claim 9, wherein the glass article comprises an alkali aluminosilicate glass.

13. The glass article of claim 12, wherein the alkali aluminosilicate glass further comprises up to about 10 mol % Li₂O.

14. The glass article of claim 12, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 4 mol % B₂O₃, wherein 1.3<

[(P₂O₅+R₂O)/M₂O₃]≦

2.3, where M₂O₃=Al₂O₃+B₂O₃, and R₂O is the sum of monovalent cation oxides present in the alkali aluminosilicate glass.

15. The glass article of claim 9, wherein the glass article has an equibiaxial flexural strength in a range from about 10 kgf up to 50 kgf as determined by abraded ring-on-ring testing.

16. The glass article of claim 9, wherein DOC≧

0.11·

t when t<

0.5 mm and 5 μ

m≦

DOC≦

100 μ

m when t≧

0.5 mm.

17. A strengthened glass, the strengthened glass having a thickness t, an inner region under a central tension CT, and at least one compressive layer under a compressive stress CS, the compressive stress layer extending from a surface of the glass to a depth of compression DOC≧

0.1·

t when t<

0.5 mm and DOC≧

50 μ

m when t≧

0.5 mm, and being adjacent to the inner region, wherein the strengthened glass has at least about a 60% survival rate when dropped in an inverted ball drop test from a height of about 80 cm onto an abrasive material disposed on the surface of the glass.

18. The strengthened glass of claim 17, wherein the compressive layer has a compressive stress CS in a range from about 500 MPa to about 1200 MPa at a surface of the glass article, wherein the compressive layer has a compressive stress profile comprising:

a. a first portion b extending from the surface to a depth d_b and having a slope m_b, wherein 3 μ

m≦

d_b≦

15 μ

m and −

40 MPa/μ

m≧

m_b≧

−

200 MPa/μ

m; and

b. a second portion c extending from d_b to up to the depth of compression DOC and having a slope m_c, wherein −

2 MPa/μ

m≧

m_c≧

−

8 MPa/μ

m.

19. The strengthened glass of claim 17, wherein the thickness t is in a range from about 0.15 mm up to about 2.0 mm.

20. The strengthened glass of claim 17, wherein the strengthened glass comprises an alkali aluminosilicate glass.

21. The strengthened glass article of claim 20, wherein the alkali aluminosilicate glass further comprises up to about 10 mol % Li₂O.

22. The strengthened glass article of claim 20, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 4 mol % B₂O₃, wherein 1.3<

[(P₂O₅+R₂O)/M₂O₃]≦

2.3, where M₂O₃=Al₂O₃+B₂O₃, and R₂O is the sum of monovalent cation oxides present in the alkali aluminosilicate glass.

23. The strengthened glass of claim 17, wherein the strengthened glass has an equibiaxial flexural strength in a range from about 10 kgf to about 50 kgf as determined by abraded ring-on-ring testing.

24. A strengthened glass, the strengthened glass having a thickness t, an inner region under a central tension CT, and at least one compressive stress layer under a compressive stress CS, the compressive stress layer extending from a surface of the glass to a depth of compression DOC, wherein DOC≧

0.1·

t when t<

0.5 mm and DOC≧

50 μ

m when t≧

0.5 mm, and being adjacent to the inner region, wherein the strengthened glass has an equibiaxial flexural strength of at least 10 kgf up to about 50 kgf as determined by abraded ring-on-ring testing.

25. The strengthened glass of claim 24, wherein the compressive layer has a surface compressive stress CS in a range from about 500 MPa to about 1200 MPa at a surface of the glass article, wherein the compressive layer has a compressive stress profile comprising:

a. a first portion b extending from the surface to a depth d_b and having a slope m_b, wherein 3 μ

m≦

d_b≦

15 μ

m and −

40 MPa/μ

m≧

m_b≧

−

200 MPa/μ

m; and

b. a second portion c extending from d_b to up to the depth of compression DOC and having a slope m_c, wherein −

2 MPa/μ

m≧

m_c≧

−

8 MPa/μ

m.

26. The strengthened glass of claim 25, wherein the strengthened glass has at least a 60% survival rate when dropped in an inverted ball drop test from a height of about 80 cm onto an abrasive material disposed on the surface of the glass.

27. The strengthened glass of claim 25, wherein −

40 MPa/μ

m≧

m_b≧

−

120 MPa/μ

m.

28. The strengthened glass of claim 24, wherein the compressive layer has a surface compressive stress CS in a range from about 150 MPa to about 400 MPa at a surface of the glass article, wherein the compressive layer has a compressive stress profile having a linear portion a extending from the surface to a depth d_a and a slope m_a, wherein the depth d_a is equal to the depth of compression DOC and −

2 MPa/μ

m≧

m_a≧

−

8 MPa/μ

m.

29. The strengthened glass article of claim 24, wherein the thickness t is in a range from about 0.15 mm up to about 2.0 mm.

30. The strengthened glass of claim 24, wherein the strengthened glass comprises an alkali aluminosilicate glass.