Down-drawable, chemically strengthened glass for cover plate

• US 7,666,511 B2
• Filed: 07/31/2007
• Issued: 02/23/2010
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Ellison, Adam James, Gomez, Sinue
• Primary Examiner(s): Blackwell; Gwendolyn
• Application Number:
  US11/888,213
• Publication Number:
  US 20080286548A1
• Time in Patent Office: 938 Days
• Field of Search: 501/53, 501/55, 501/65, 501/66, 501/68, 501/69, 501/70, 501/72
• US Class Current: 428/426
• CPC Class Codes: C03B 17/06 Forming glass sheets
• 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 3/091 containing aluminium
• CPC Class Codes: Y02P 40/57 Improving the yield, e-g- reduction of reject rates
• CPC Class Codes: Y10T 428/315 Surface modified glass [e.g., tempered, strengthened, etc.]

Abstract

An alkali aluminosilicate glass that is chemically strengthened and has a down-drawable composition. The glass has a melting temperature less than about 1650° C. and a liquidus viscosity of at least 130 kpoise and, in one embodiment, greater than 250 kpoise. The glass undergoes ion exchange at relatively low temperatures to a depth of at least 30 μm.

Claims

1. An alkali aluminosilicate glass, the glass comprising:

64 mol %≦

SiO₂≦

68 mol %;

12 mol %≦

Na₂O≦

16 mol %;

8 mol %≦

Al₂O₃≦

12 mol %;

0 mol %≦

B₂O₃≦

3 mol %;

2 mol %≦

K₂O≦

5 mol %;

4 mol %≦

MgO≦

6 mol %; and

0 mol %≦

CaO≦

5 mol %, wherein;

66 mol %≦

SiO₂+B₂O₃+CaO≦

69 mol %;

Na₂O+K₂O+B₂O₃+MgO+CaO+SrO>

10 mol %;

5 mol %≦

MgO+CaO+SrO≦

8 mol %;

(Na₂O+B₂O₃)—

Al₂O₃≦

2 mol %;

2 mol %≦

Na₂O—

Al₂O₃≦

6 mol %; and

4 mol %≦

(Na₂O+K₂O)—

Al₂O₃≦

10 mol %, and wherein the glass has a liquidus viscosity of at least 130 kpoise.

2. The glass according to claim 1, wherein the glass is down-drawable.

3. The glass according to claim 1, wherein the glass is substantially free of lithium.

4. The glass according to claim 1, wherein the glass is ion exchanged.

5. The glass according to claim 4, wherein the glass, when ion exchanged, has a surface compressive stress of the glass of at least about 200 MPa.

6. The glass according to claim 4, wherein the glass, when ion exchanged, has a surface compressive layer having a depth of at least about 30 μ

m.

7. The glass according to claim 1, wherein the glass has a liquidus viscosity of at least 250 kpoise.

8. The glass according to claim 1, wherein the glass has a thickness ranging from about 0.3 mm up to about 3 mm.

9. The glass according to claim 8, wherein the glass has a thickness ranging from about 0.3 mm up to about 1.5 mm.

10. The glass according to claim 9, wherein the glass has a warpage of less than about 0.5 mm, as determined for a 300 mm×

400 mm sheet.

11. The glass according to claim 10, wherein the warpage is less than about 0.3 mm.

12. The glass according to claim 1, wherein the glass is a cover plate.

13. The glass according to claim 12, wherein the glass is a cover plate for a mobile electronic device.

14. The glass according to claim 1, wherein the glass is slot drawn or fusion drawn.

15. A lithium-free glass having a surface compressive stress of at least about 200 MPa, a surface compressive layer having a depth of at least in a range from about 30 μ

m up to about 100 μ

m, and a thicknessof at least about 0.3 mm.

16. The lithium-free glass according to claim 15, wherein the compressive stress is at least about 600 MPa, the depth of surface compressive layer is at least 40 μ

m, and the thickness is in a range from about 0.7 mm up to about 1.1 mm.

17. The lithium-free glass according to claim 15, wherein the glass comprises 64 mol %≦

SiO₂≦

68 mol %;

12 mol %≦

Na₂≦

16 mol %;

8 mol %≦

Al₂O₃≦

12 mol %;

0 mol %≦

B₂O₃≦

3 mol %;

2 mol %≦

K₂O≦

5 mol %;

4 mol %≦

MgO≦

6 mol %; and

0 mol %≦

CaO≦

5 mol %, wherein;

66 mol %≦

SiO₂+B₂O₃+CaO≦

69 mol %;

Na₂O+K₂O+B₂O₃+MgO+CaO+SrO>

10 mol %;

5 mol %≦

MgO+CaO+SrO≦

8 mol %;

(Na₂O+B₂O₃) —

Al₂O₃≦

2 mol %;

2 mol %≦

Na₂O—

Al₂O₃≦

6 mol %; and

4 mol %≦

(Na₂O+K₂O)—

Al₂O₃≦

10 mol %, and wherein the glass has a liquidus viscosity of at least 130 kpoise.

18. The lithium-free glass according to claim 17, wherein the glass has a liquidus viscosity of at least 250 kpoise.

19. The lithium-free glass according to claim 15, wherein the glass has a thickness ranging from about 0.3 mm up to about 3 mm.

20. The lithium-free glass according to claim 19, wherein the glass has a thickness ranging from about 0.3 mm up to about 1.5 mm.

21. The lithium-free glass according to claim 15, wherein the glass is a cover plate.

22. The lithium-free glass according to claim 15, wherein the glass is a cover plate for a mobile electronic device.

23. The lithium-free glass according to claim 15, wherein the glass has a warpage of less than about 0.5 mm, as determined for a 300 mm×

400 mm sheet.

24. The lithium-free glass according to claim 15, wherein the warpage is less than about 0.3 mm.

25. The lithium-free glass according to claim 15, wherein the lithium-free glass is fusion drawn or slot drawn.

26. A mobile electronic device, the mobile electronic device comprising an alkali aluminosilicate glass cover plate, the glass cover plate comprising:

64 mol %≦

SiO₂≦

68 mol %;

12 mol %≦

Na₂O≦

16 mol %;

8 mol %≦

Al₂O₃≦

12 mol %;

0 mol %≦

B₂O₃≦

3 mol %;

2 mol %≦

K₂O≦

5 mol %;

4 mol %≦

MgO≦

6 mol %; and

0 mol %≦

CaO≦

5 mol %, wherein;

66 mol %≦

SiO₂+B₂O₃+CaO≦

69 mol %;

Na₂O+K₂O+B₂O₃+MgO+CaO+SrO>

10 mol %;

5 mol %≦

MgO+CaO+SrO≦

8 mol %;

(Na₂O+B₂O₃)—

Al₂O₃≦

2 mol %;

2 mol %≦

Na₂O—

Al₂O₃≦

6 mol %; and

4 mol %≦

(Na₂O+K₂O)—

Al₂O₃≦

10 mol %, and wherein the glass has a liquidus viscosity of at least 130 kpoise.

27. The mobile electronic device according to claim 26, wherein the glass cover plate is substantially free of lithium.

28. The mobile electronic device according to claim 26, wherein the glass cover plate is ion exchanged.

29. The mobile electronic device according to claim 28, wherein the glass cover plate, when ion exchanged, has a surface compressive stress at a surface of the glass of at least 200 MPa.

30. The mobile electronic device according to claim 28, wherein the glass cover plate, when ion exchanged, has a compressive surface layer having a depth of at least about 30 μ

m.

31. The mobile electronic device according to claim 26, wherein the glass cover plate has a liquidus viscosity of at least 250 kpoise.

32. The mobile electronic device according to claim 26, wherein the glass cover plate has a thickness ranging from about 0.3 mm up to about 3 mm.

33. The mobile electronic device according to claim 32, wherein the glass cover plate has a thickness ranging from about 0.3 mm up to about 1.5 mm.

34. The mobile electronic device according to claim 32, wherein the glass cover plate has a warpage of less than about 0.5 mm, as determined for a 300 mm×

400 mm sheet.

35. The mobile electronic device according to claim 34, wherein the warpage is less than about 0.3 mm.

36. The mobile electronic device according to claim 26, wherein the glass is fusion drawn or slot-drawn.

37. An alkali aluminosilicate glass cover plate, the cover plate comprising:

64 mol %≦

SiO₂≦

68 mol %;

12 mol %≦

Na₂O≦

16 mol %;

8 mol %≦

Al₂O₃≦

12 mol %;

0 mol % ≦

B₂O₃≦

3 mol %;

2 mol %≦

K₂O≦

5 mol %;

4 mol %≦

MgO≦

6 mol %; and

0 mol %≦

CaO≦

5 mol %, wherein;

66 mol %≦

SiO₂+B₂O₃+CaO≦

69 mol %;

Na₂O+K₂O+B₂O₃+MgO+CaO +SrO>

10 mol %;

5 mol %≦

MgO+CaO+SrO≦

8 mol %;

(Na₂O+B₂O₃)—

Al₂O₃≦

2 mol %;

2 mol %≦

Na₂O—

Al₂O₃≦

6 mol %; and

4 mol %≦

(Na₂O+K₂O)—

Al₂O₃≦

10 mol %, and wherein the glass has a liquidus viscosity of at least 130 kpoise.

38. The cover plate according to claim 37, wherein the cover plate is substantially free of lithium.

39. The cover plate according to claim 37, wherein the cover plate is ion exchanged.

40. The cover plate according to claim 39, wherein the cover plate, when ion exchanged, has a surface compressive stress at a surface of the glass of at least about 200 MPa.

41. The cover plate according to claim 39, wherein the cover plate, when ion exchanged, has a compressive surface layer having a depth of at least about 30 μ

m.

42. The cover plate according to claim 37, wherein the cover plate has a liquidus viscosity of at least 250 kpoise.

43. The cover plate according to claim 37, wherein the cover plate has a thickness ranging from about 0.3 mm up to about 3 mm.

44. The cover plate according to claim 43, wherein the cover plate has a thickness ranging from about 0.3 mm up to about 1.5 mm.

45. The cover plate according to claim 43, wherein the cover plate has a warpage of less than about 0.5 mm, as determined for a 300 mm×

400 mm sheet.

46. The cover plate according to claim 45, wherein the warpage is less than about 0.3 mm.

47. The cover plate according to claim 37, wherein the glass is fusion drawn or slot-drawn.