Patent US3978362A successfully refreshed from Google Patents.
US3978362A
Expired / Lapsed
US
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Glass envelope for tungsten-bromine lamp
Assignee: Corning Glass Works
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Filing: 1975-08-07
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Granted: 1976-08-31
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Expires: 1995-08-07
Abstract
Abstract The invention relates to glasses especially suitable for the envelope of a tungsten-bromine incandescent lamp and which can be sealed directly to molybdenum. Such glasses exhibit strain points in excess of 700°C., a viscosity at the liquidus, of at least 100,000 poises, and a coefficient of thermal expansion (0°-300°C.) between about 48-55 × 10 - 7 /°C. More particularly, such glasses consist essentially, by weight on the oxide basis, of about 58-63% SiO 2 , 13-16% Al 2 O 3 , 14-21% CaO, 0-5% MgO, and 0-7% BaO, the total CaO + MgO + BaO constituting at least about 19%.
Inventors
- 👤 William H. Dumbaugh, Jr.
- 👤 Roger R. Genisson
- 👤 Michel R. Lestrat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:29
CPC Classifications
H; H01; H01K; H01K1/00; H01K1/28; C; C03; C03C; C03C3/00; C03C3/04; C03C3/076; C03C3/083; C03C3/085; C03C3/087
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
126 words
A tungsten-bromine incandescent lamp having an envelope made from a glass exhibiting a strain point above 700°C., a coefficient of thermal expansion (0°-300°C.) in the range of about 48-55 × 10 - 7 /°C., a mismatch with molybdenum metal at the set point of the glass not exceeding about 250 PPM, an operable melting temperature not in excess of about 1550°C., a viscosity at the liquidus temperature of at least 100,000 poises, a liquidus temperature less than about 1200°C., and a very low permeability to hydrogen, said glass consisting essentially, by weight on the oxide basis, of about 14-21% CaO, 0-5% MgO, 0-7% BaO, the total CaO + MgO + BaO being at least 19%, 13-16% Al 2 O 3 , and 58-63% SiO 2 .
Claim 2
Dependent Claim
126 words
A tungsten-bromine incandescent lamp having an envelope made from a glass exhibiting a strain point above 700°C., a coefficient of thermal expansion (0°-300°C.) in the range of about 48-55 × 10 - 7 /°C., a mismatch with molybdenum metal at the set point of the glass not exceeding about 250 PPM, an operable melting temperature not in excess of about 1550°C., a viscosity at the liquidus temperature of at least 100,000 poises, a liquidus temperature less than about 1200°C., and a very low permeability to hydrogen, said glass consisting essentially, by weight on the oxide basis, of about 14-21% CaO, 0-5% MgO, 0-7% BaO, the total CaO + MgO + BaO being at least 19%, 13-16% Al 2 O 3 , and 58-63% SiO 2 .
Claim 3
Dependent Claim
25 words
A tungsten-bromine incandescent lamp according to claim 1 wherein said glass also contains up to 10% total of SrO and/or La 2 O 3 .
Claim 4
Dependent Claim
38 words
A tungsten-bromine incandescent lamp according to claim 1 wherein said glass consists essentially, by weight on the oxide basis, of about 1-5% MgO, 2-7% BaO, 16-20% CaO, 13-16% Al 2 O 3 , and 58-63% SiO 2 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-31 | 1980-03-01 | 1980-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-31 | 1984-03-01 | 1984-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-31 | 1988-03-01 | 1988-08-31 | $7700.00 | Window Closed / Lapsed |