Patent US4044276A successfully refreshed from Google Patents.
US4044276A
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High pressure mercury vapor discharge lamp having improved electrodes
Assignee: GTE Sylvania Inc
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Filing: 1976-04-09
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Granted: 1977-08-23
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Expires: 1996-04-09
Abstract
Abstract The emitter material on the electrode of a high intensity discharge lamp comprises hafnium oxide, barium oxide and calcium oxide.
Inventors
- 👤 William M. Keeffe
- 👤 Frederic Koury
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:38
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/04; H01J61/06; H01J61/073; H01J61/0735; H01J61/0737
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
72 words
In a high pressure mercury vapor arc discharge tube having a main electrode at each end thereof and containing a fill including mercury and a starting gas, the improvement which comprises an electron-emitting material on the electrodes comprising barium oxide, calcium oxide and hafnium oxide, the hafnium oxide constituting about 1/6 to 2/3 by weight of said material, the electrode temperature during normal lamp operation being between about 1200° and 1700° C.
Claim 2
Dependent Claim
72 words
In a high pressure mercury vapor arc discharge tube having a main electrode at each end thereof and containing a fill including mercury and a starting gas, the improvement which comprises an electron-emitting material on the electrodes comprising barium oxide, calcium oxide and hafnium oxide, the hafnium oxide constituting about 1/6 to 2/3 by weight of said material, the electrode temperature during normal lamp operation being between about 1200° and 1700° C.
Claim 3
Dependent Claim
28 words
The lamp of claim 1 wherein the electrode comprises a tungsten rod having two concentric encircling tungsten coils thereon and said material is disposed between said two coils.
Claim 4
Dependent Claim
29 words
For use in a high intensity arc discharge lamp, an electron-emitting composition disposed on a refractory metal electrode and consisting essentially of hafnium oxide, barium oxide and calcium oxide.
Claim 5
Dependent Claim
29 words
For use in a high intensity arc discharge lamp, an electron-emitting composition disposed on a refractory metal electrode and consisting essentially of hafnium oxide, barium oxide and calcium oxide.
References Cited (Backward Citations)
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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) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |