Patent US4047067A successfully refreshed from Google Patents.
US4047067A
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Sodium halide discharge lamp with an alumina silicate barrier zone in fused silica envelope
Assignee: General Electric Co
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Filing: 1974-06-05
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Granted: 1977-09-06
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Expires: 1994-06-05
Abstract
Abstract A graded alumina silicate glass layer or zone is formed at the surface of fused silica by first applying a polycrystalline coating of aluminum oxide to the silica and then fusing the coating into the silica at a high temperature. Such a zone on the outside of the fused silica arc tube of a metal halide lamp containing sodium is particularly effective to inhibit sodium loss by diffusion through the tube walls.
Inventors
- 👤 Edward M. Clausen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:07
CPC Classifications
C; C03; C03C; C03C17/00; C03C17/22; C03C17/23; H; H01; H01J; H01J61/00; H01J61/02; H01J61/12; H01J61/125; H01J61/30; H01J61/302; C03C2217/00; C03C2217/20; C03C2217/21; C03C2217/214; C03C2217/23; C03C2218/00; C03C2218/10; C03C2218/11; C03C2218/112; C03C2218/17
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
71 words
A metal halide lamp comprising a fused silica envelope containing a fill including sodium halide, said envelope having on the outside an alumina silicate glass zone at the surface serving as a barrier to sodium diffusion, said zone comprising aluminum oxide heat-diffused into the fused silica, said zone being from 5 to 25 microns thick and the peak concentration of aluminum oxide in it ranging from 5 to 25 weight percent.
Claim 2
Dependent Claim
71 words
A metal halide lamp comprising a fused silica envelope containing a fill including sodium halide, said envelope having on the outside an alumina silicate glass zone at the surface serving as a barrier to sodium diffusion, said zone comprising aluminum oxide heat-diffused into the fused silica, said zone being from 5 to 25 microns thick and the peak concentration of aluminum oxide in it ranging from 5 to 25 weight percent.
References Cited (Backward Citations)
CA884498A
Cited
US2568459A
Cited
GB741556A
Cited
US3259777A
Cited
GB1034122A
Cited
US3350598A
Cited
US3845343A
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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) | 1980-09-05 | 1981-03-07 | 1981-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-05 | 1985-03-07 | 1985-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-05 | 1989-03-07 | 1989-09-06 | $7700.00 | Window Closed / Lapsed |