US4156826A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mercury arc lamps
Assignee: RCA Licensing Corp
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Filing: 1978-05-01
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Granted: 1979-05-29
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Expires: 1998-05-01
Abstract
Abstract A mercury arc lamp envelope is made of high purity synthetic fused silica which contains total metallic impurities of less than one part per million by weight and OH radical content of less than five parts per million by weight. Lamps having envelopes made from this material show little or no devitrification after 1000 hours of operation.
Inventors
- 👤 Karl G. Hernqvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 02:39
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70008; G03F7/70016; H; H01; H01J; H01J61/00; H01J61/02; H01J61/30; H01J61/302
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
75 words
In a high pressure mercury discharge device including an envelope, having lead-in conductors sealed in and extending through the ends thereof and terminating in electrodes, and having pools of mercury retained within said envelope around said electrodes, the improvement comprising, the composition of said envelope comprising synthetic fused silica having total metallic impurities of less than 1 part per million by weight and OH radical content of less than 5 parts per million by weight.
Claim 2
Dependent Claim
75 words
In a high pressure mercury discharge device including an envelope, having lead-in conductors sealed in and extending through the ends thereof and terminating in electrodes, and having pools of mercury retained within said envelope around said electrodes, the improvement comprising, the composition of said envelope comprising synthetic fused silica having total metallic impurities of less than 1 part per million by weight and OH radical content of less than 5 parts per million by weight.
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) | 1982-05-28 | 1982-11-27 | 1983-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-28 | 1986-11-27 | 1987-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-28 | 1990-11-27 | 1991-05-29 | $7700.00 | Window Closed / Lapsed |