Glasses for flat panel displays

• US 20020082158A1
• Filed: 11/16/2001
• Published: 06/27/2002
• Est. Priority Date: 11/30/1998
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Ellison, Adam J.G., Morena, Robert, Lapp, Josef C., Kohli, Jeffrey T., Hares, George B., Chacon, Lisa C.
• Granted Patent: US 6,831,029 B2
• Time in Patent Office: Days
• US Class Current: 501/66
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C09K 2323/023 Organic silicon compound, e.g. organosilicon
• CPC Class Codes: Y10T 428/24 Structurally defined web or sheet [e.g., overall dimension, etc.]

Abstract

Glasses are disclosed which are used to produce substrates in flat panel display devices. The glasses exhibit a density less than about 2.45 gm/cm³ and a liquidus viscosity greater than about 200,000 poises, the glass consisting essentially of the following composition, expressed in terms of mol percent on an oxide basis: 65-75 SiO₂, 7-13 Al₂O₃, 5-15 B₂O₃, 0-3 MgO, 5-15 CaO, 0-5 SrO, and essentially free of BaO. The glasses also exhibit a strain point exceeding 650° C.

Claims

1. An aluminosilicate glass exhibiting a density less than about 2.45 g/cm³ and a liquidus viscosity greater than about 200,000 poises, the glass consisting essentially of the following composition as calculated in mol percent on an oxide basis:

65-75 SiO₂, 7-13 Al₂O₃, 5-15 B₂O₃, 0-3 MgO, 5-15 CaO, 0-5 SrO, and essentially free of BaO.

2. The glass of claim 1, wherein the RO/Al₂O₃ ratio is between 0.9 and 1.2, wherein R represents Mg, Ca, Sr and Ba.

3. The glass of claim 1, wherein the glass has a strain point greater than about 650°

C.

4. The glass of claim 1, wherein the glass has a linear coefficient of thermal expansion (CTE) over the temperature range 0-300°

C. between 28-35×

10<sup>−

7</sup>/°

C.

5. The glass of claim 4, wherein the glass has a strain point greater than about 660°

C.

6. The glass of claim 4, wherein the glass has a melting temperature less than about 1700°

C.

7. The glass of claim 4, wherein the glass has a CTE of 28-33×

10<sup>−

7</sup>/°

C.

8. The glass of claim 1, wherein the glass exhibits a weight loss of less than 0.5 mg/cm² after immersion in a solution of 1 part 50 wt. % HF and 10 parts 40 wt. % NH₄F for 5 minutes at 30°

C.

9. The glass of claim 1, wherein the glass has a liquidus viscosity greater than about 400,000 poises.

10. A glass according to claim 1, wherein the glass has a liquidus viscosity greater than about 600,000 poises.

11. A glass according to claim 1, wherein the glass contains between 0-1 mole percent MgO when the glass contains no SrO.

12. In a flat panel display device, the improvement comprising a substrate in accordance with claim 1.

13. The flat panel display device of claim 12, wherein the substrate has an average surface roughness less than about 0.5 nm.

14. The flat panel display device of claim 12, wherein the substrate has an average internal stress less than about 150 psi.

15. A glass according to claim 1, wherein the glass has a composition consisting essentially of, as expressed in mol percent on an oxide basis:

67-73 SiO₂, 8-11.5 Al₂O₃, 8-12 B₂O₃, 0-1 MgO, 5.5-11 CaO, and 0-5 SrO.

16. The glass of claim 15, wherein the glass has a strain point greater than about 650°

C.

17. The glass of claim 15, wherein the glass has a CTE of 28-33×

10<sup>−

7</sup>/°

C.

18. The glass of claim 17, wherein the glass has a strain point greater than about 660°

C.

19. The glass of claim 17, wherein the glass has a melting temperature less than about 1700°

C.

20. The glass of claim 17, wherein the glass has a liquidus viscosity greater than 400,000 poises.

21. The glass of claim 17, wherein the glass has a liquidus viscosity greater than about 800,000 poises

22. In a flat panel display device, the improvement comprising a substrate in accordance with claim 17.

23. The flat panel display device of claim 22, wherein the substrate has an average surface roughness less than about 0.5 nm.

24. The flat panel display device of claim 22, wherein the substrate has an average internal stress less than about 150 psi.

25. In a flat panel display device, the improvement comprising a substrate in accordance with claim 21.

27. A substrate according to claim 26, wherein the glass exhibits a strain point exceeding 660°

C.

28. The substrate according to claim 26, wherein the substrate has an average surface roughness less than about 0.5 nm.

29. The substrate according to claim 26, wherein the substrate has an average internal stress less than about 150 psi.

26. A substrate for a flat panel display device, wherein the substrate is comprised of a flat, transparent glass exhibiting a density less than about 2.40 g/cm³, a linear coefficient of thermal expansion (CTE) over the temperature range 0-300°

C. between 28-33×

10<sup>−

7</sup>/°

C. and having a liquidus viscosity greater than about 400,000 poises, the glass consisting essentially of the following composition as calculated in mol percent on an oxide basis;

65-75 SiO₂, 7-13 Al₂O₃, 5-15 B₂O₃, 0-3 MgO, 5-15 CaO, 0-5 SrO, and essentially free of BaO and the RO/Al₂O₃ ratio is 0.92-0.96, wherein R represents Mg, Ca, Sr, and Ba.