US3742283A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Press seal for lamp having fused silica envelope
Assignee: GTE Sylvania Inc
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Filing: 1971-10-28
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Granted: 1973-06-26
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Expires: 1991-10-28
Abstract
Abstract Lead-in wires of lamps are sealed in a vitreous silica envelope through the use of a graded seal in which two abutting segments of refractory metal wires are disposed in a tube or tubes of a cermet formed of an admixture of powder refractory metal and vitreous silica. The lead-in wires and cermet tubes are disposed in a specially formed press seal of a vitreous silica envelope.
Inventors
- 👤 F Loughridge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:43
CPC Classifications
H; H01; H01J; H01J5/00; H01J5/32; H01J5/38
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
64 words
The lamp according to claim 1 wherein at least two concentric cermet tubes are disposed around said lead-in wires, the innermost tube having a coefficient of expansion closest to that of said lead-in wires and being sealed to said lead-in wires and the outermost tube being sealed to said press-seal and having a coefficient of expansion closest to that of the vitreous silica thereof.
Claim 2
Dependent Claim
23 words
The lamp according to claim 1 wherein said cermet tube is formed of a sintered admixture of powdered refractory metal and powdered quartz.
Claim 3
Dependent Claim
57 words
The lamp according to claim 1 wherein the silica has a coefficient of expansio of about 4 X 10 7 in/in/*C and the lead-in wire is tungsten having a coefficient of expansion of about 44 X 10 7 in/in/*C and the cermet tube has a coefficient of expansion greater than the silica but less than the tungsten.
Claim 4
Dependent Claim
13 words
The lamp according to claim 3 wherein said powdered refractory metal is tungsten.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |