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US4824808A Expired / Lapsed US ⏱️ 0.0 years remaining

Substrate glass for liquid crystal displays

Assignee: Corning Glass Works
•
Filing: 1987-11-09
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Granted: 1989-04-25
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Expires: 2007-11-09
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Abstract

Abstract Glass compositions suitable for the manufacture of sheet glass for liquid crystal display (LCD) devices are disclosed, such glasses consisting essentially, in cation percent, of about 52-58% SiO 2 , 12.5-18% Al 2 O 3 , 20-23% B 2 O 3 , 0-4% MgO, 0-6% CaO, 0-6% SrO, 1-9% BaO, 8-12% MgO+CaO+Sro+BaO, -3% ZnO, and 0-1% of fining agents. These glasses have a strain point in excess of 625° C., an average linear coefficient of thermal expansion in the range of about 20-60×10 -7 /°C. over the range 25°-300° C., an internal liquidus temperature not exceeding about 1050° C., and chemical durability sufficient to exhibit a weight loss in 5% HCl at 95° C. not exceeding about 10 mg/cm 2 in a 24 hour period, and so offer the glass stability necessary for overflow downdraw sheet forming and the high strain point and chemical durability needed for LCD manufacture.

Inventors

  • 👤 William H. Dumbaugh, Jr.

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 23:30
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; C; C03; C03C; C03C3/00; C03C3/04; C03C3/076; C03C3/089; C03C3/091; C03C3/093

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 114 words
A glass composition consisting essentially, in cation percent, of about 52-58% SiO 2 , 12.5-18% Al 2 O 3 , 20-23% B 2 O 3 , 0-4% MgO, 0-6% CaO, 0-6% SrO, 1-9% BaO, 8-12% MgO+CaO+SrO+BaO, 0-3% ZnO, and 0-1% of fining agents, said composition providing a glass having a strain point in excess of 625° C., an average linear coefficient of thermal expansion in the range of about 20-60×10 -7 /°C. over the temperature range 25°-300° C., an internal liquidus temperature not exceeding about 1050° C., and chemical durability sufficient to exhibit a weight loss in 5% HCl at 95 ° C. not exceeding about 10 mg/cm 2 in a 24 hour period.
Claim 2
Dependent Claim 114 words
A glass composition consisting essentially, in cation percent, of about 52-58% SiO 2 , 12.5-18% Al 2 O 3 , 20-23% B 2 O 3 , 0-4% MgO, 0-6% CaO, 0-6% SrO, 1-9% BaO, 8-12% MgO+CaO+SrO+BaO, 0-3% ZnO, and 0-1% of fining agents, said composition providing a glass having a strain point in excess of 625° C., an average linear coefficient of thermal expansion in the range of about 20-60×10 -7 /°C. over the temperature range 25°-300° C., an internal liquidus temperature not exceeding about 1050° C., and chemical durability sufficient to exhibit a weight loss in 5% HCl at 95 ° C. not exceeding about 10 mg/cm 2 in a 24 hour period.
Claim 3
Dependent Claim 84 words
A glass composition consisting essentially, in cation percent, of about 53-57% SiO 2 , 15-17% Al 2 O 3 , 20-22% B 2 O 3 , 1-6% BaO, 1-2% MgO, 0-4% CaO, 0-4% SrO, and 10-12% total of MgO+BaO+CaO+BaO, said composition providing a glass exhibiting a strain point in excess of 630 ° C., a thermal expansion coefficient in the range of about 38-43×10 -7 /°C., a liquidus temperature below 1042° C., and a viscosity at the liquidus in excess of 1.3×10 5 poises.
Claim 4
Dependent Claim 84 words
A glass composition consisting essentially, in cation percent, of about 53-57% SiO 2 , 15-17% Al 2 O 3 , 20-22% B 2 O 3 , 1-6% BaO, 1-2% MgO, 0-4% CaO, 0-4% SrO, and 10-12% total of MgO+BaO+CaO+BaO, said composition providing a glass exhibiting a strain point in excess of 630 ° C., a thermal expansion coefficient in the range of about 38-43×10 -7 /°C., a liquidus temperature below 1042° C., and a viscosity at the liquidus in excess of 1.3×10 5 poises.
Claim 5
Dependent Claim 17 words
A glass composition in accordance with claim 2 which contains 3-4% CaO, 1-3% BaO, and 1-3% SrO.

References Cited (Backward Citations)

US2393449A Cited
US2834738A Cited
US3310413A Cited
US3338696A Cited
US3978362A Cited
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US4409337A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-04-24 1992-10-24 1993-04-25 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-04-24 1996-10-24 1997-04-25 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-04-24 2000-10-24 2001-04-25 $7700.00 Window Closed / Lapsed

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