High liquidus viscosity glasses for flat panel displays

• US 5,374,595 A
• Filed: 11/22/1993
• Issued: 12/20/1994
• Est. Priority Date: 01/22/1993
• Status: Expired due to Term

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Lapp, Josef C., Moffatt, Dawne M., Dumbaugh, William H. Jr.
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): JONES, DEBORAH D
• Application Number:
  US08/155,483
• Time in Patent Office: 393 Days
• Field of Search: 501/55, 501/63, 501/64, 501/66, 501/69, 501/70, 501/72, 359/82
• US Class Current: 501/66
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: G02F 1/133302 Rigid substrates, e.g. inorganic substrates

Abstract

This invention is related to glasses for use as substrates in flat panel display devices; more specifically, for use as substrates in LCDs which utilize polycrystalline silicon thin film transistors. The compositions for the inventive glasses are essentially free from alkali metal oxides and consist essentially, in mole percent, of

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SiO₂ 64-70 Y₂ O₃ 0-5 Al₂ O₃ 9.5-14 MgO 0-5 B₂ O₃ 5-10 CaO 3-13 TiO₂ 0-5 SrO 0-5.5 Ta₂ O₅ 0-5 BaO 2-7 Nb₂ O₅ 0-5 MgO + CaO + SrO + BaO 10-20. ______________________________________

Claims

1. A substrate for a flat panel display device wherein said substrate is comprised of a flat, transparent glass exhibiting a strain point higher than 650°

C., a linear coefficient of thermal expansion over the temperature range 0°

-300°

C. between 32-46×

10^-7 /°

C., and a weight loss of less than 2 mg/cm² after immersion for 24 hours in an aqueous 5% by weight HCl solution, said glass being essentially free from alkali metal oxides and consisting essentially, expressed in terms of mole percent on the oxide basis, of

space="preserve" listing-type="tabular">______________________________________ SiO.sub.2 64-70 Y.sub.2 O.sub.3 0-5 Al.sub.2 O.sub.3 9.5-14 MgO 0-5 B.sub.2 O.sub.3 5-10 CaO 3-13 TiO.sub.2 0-5 SrO 0-5.5 T.sub.2 O.sub.5 0-5 BaO 2-7 Nb.sub.2 O.sub.5 0-5 MgO + CaO + SrO + BaO 10-20. ______________________________________

2. A substrate according to claim 1 wherein the liquidus temperature of said glass is no higher than 1200°

C.

3. A substrate according to claim 1 wherein the viscosity of said glass at the liquidus temperature thereof is greater than about 20,000 Pa.s.

4. A substrate according to claim 1 wherein said glass exhibits a melting viscosity of about 20 Pa.s at a temperature below 1675°

C.

5. A substrate according to claim 1 wherein said glass exhibits a linear coefficient of thermal expansion between 32-40×

10^-7 /°

C.

6. A substrate according to claim 5 wherein silicon chips are mounted directed onto said glass utilizing chip-on-glass technology.

7. A substrate according to claim 5 wherein said glass is essentially free from alkali metal oxides and consists essentially, expressed in terms of mole percent on the oxide basis, of

8. A substrate according to claim 7 wherein the liquidus temperature of said glass is no higher than 1125°

C.

9. A substrate according to claim 7 wherein the viscosity of said glass at the liquidus temperature thereof is greater than 60,000 Pa.s.

11. A substrate according to claim 7 wherein silicon chips are mounted directly onto said glass utilizing chip-on-glass technology.

10. A substrate according to claim wherein said glass exhibits a melting viscosity of about 20 Pa.s at a temperature below 1675°

C.

12. A glass exhibiting a strain point higher than 650°

C., a linear coefficient of thermal expansion over the temperature range 0°

-300°

C. between 32-46×

10^-7 /°

C., and a weight loss of less than 2 mg/cm² after immersion for 24 hours in an aqueous 5% by weight HCl solution, said glass being essentially free from alkali metal oxides and consisting essentially, expressed in terms of mole percent on the oxide basis, of

space="preserve" listing-type="tabular">______________________________________ SiO.sub.2 64-70 Y.sub.2 O.sub.3 0-5 Al.sub.2 O.sub.3 9.5-14 MgO 0-5 B.sub.2 O.sub.3 5-10 CaO 3-13 TiO.sub.2 0-5 SrO 0-5.5 Ta.sub.2 O.sub.5 0-5 BaO 2-7 Nb.sub.2 O.sub.5 0-5 MgO + CaO + SrO + BaO 10-20. ______________________________________

13. A glass according to claim 12 wherein the liquidus temperature thereof is no higher than 1200°

C.

14. A glass according to claim 12 wherein the viscosity thereof at the liquidus temperature is greater than about 20,000 Pa.s.

15. A glass according to claim 12 wherein said glass exhibits a melting viscosity of about 20 Pa.s at a temperature below 1675°

C.

16. A glass according to claim 12 wherein said glass exhibits a linear coefficient of thermal expansion between 32-40×

10^-7 /°

C.

17. A glass according to claim 16 wherein said glass consists essentially of

18. A glass according to claim 17 wherein the liquidus temperature thereof is no higher than 1125°

C.

19. A glass according to claim 17 wherein the viscosity thereof at the liquidus temperature is greater than 60,000 Pa.s.

20. In a flat panel display device containing a flat, transparent glass substrate, the improvement wherein said glass exhibits a strain point higher than 650°

C., a linear coefficient of thermal expansion over the temperature range of 0°

-300°

C. between 32-46×

10^-7 /°

C., and a weight loss of less than 2 mg/cm² after immersion for 24 hours in an aqueous solution of 5% by weight HCl, said glass being essentially free from alkali metal oxides and consisting essentially, expressed in terms of mole percent on the oxide basis, of

space="preserve" listing-type="tabular">______________________________________ SiO.sub.2 64-70 Y.sub.2 O.sub.3 0-5 Al.sub.2 O.sub.3 9.5-14 MgO 0-5 B.sub.2 O.sub.3 5-10 CaO 3-13 TiO.sub.2 0-5 SrO 0-5.5 T.sub.2 O.sub.5 0-5 BaO 2-7 Nb.sub.2 O.sub.5 0-5 MgO + CaO + SrO + BaO 10-20. ______________________________________

21. In a flat panel display device according to claim 20 wherein the liquidus temperature of said glass is no higher than 1200°

C.

22. In a flat panel display device according to claim 20 wherein the viscosity of said glass at the liquidus temperature thereof is greater than about 20,000 Pa.s.

23. In a flat panel display device according to claim 20 Wherein said glass exhibits a melting viscosity of about 20 Pa.s at a temperature below 1675°

C.

24. In a flat panel display device according to claim 20 wherein said glass exhibits a linear coefficient of thermal expansion between 32-40×

10^-7 /°

C.

25. In a flat panel display device according to claim 24 wherein silicon chips are mounted directly onto said glass utilizing chip-on-glass technology.

26. In a flat panel display device according to claim 24 wherein said glass is essentially free from alkali metal oxides and consists essentially, expressed in terms of mole percent on the oxide basis, of

27. In a flat panel display device according to claim 26 wherein the liquidus temperature of said glass in no higher than 1125°

C.

28. In a flat panel display device according to claim 26 wherein the viscosity of said glass at the liquidus temperature thereof is greater than 60,000 Pa.s.

29. In a flat panel display device according to claim 26 wherein said glass exhibits a melting viscosity of about 20 Pa.s at a temperature below 1675°

C.

30. In a flat panel display device according to claim 26 wherein silicon chips are mounted directly onto said glass utilizing chip-on-glass technology.