High liquidus viscosity glasses for flat panel displays
AssigneeCorning Incorporated
InventorsWilliam H. Dumbaugh, Jr., Josef C. Lapp, Dawne M. Moffatt
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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 ______________________________________ 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. ______________________________________
Claims30
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.degree. C., a linear coefficient of thermal expansion over the temperature range 0.degree.-300.degree. C. between 32-46.times.10.sup.-7 /.degree. C., and a weight loss of less than 2 mg/cm.sup.2 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
- ______________________________________ 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. ______________________________________
A substrate according to claim wherein said glass exhibits a melting viscosity of about 20 Pa.s at a temperature below 1675.degree. C.
A glass exhibiting a strain point higher than 650.degree. C., a linear coefficient of thermal expansion over the temperature range 0.degree.-300.degree. C. between 32-46.times.10.sup.-7 /.degree. C., and a weight loss of less than 2 mg/cm.sup.2 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
- ______________________________________ 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. ______________________________________
In a flat panel display device containing a flat, transparent glass substrate, the improvement wherein said glass exhibits a strain point higher than 650.degree. C., a linear coefficient of thermal expansion over the temperature range of 0.degree.-300.degree. C. between 32-46.times.10.sup.-7 /.degree. C., and a weight loss of less than 2 mg/cm.sup.2 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
- ______________________________________ 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. ______________________________________
Dependencies are inferred from the claim text.