US3919581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thoria-yttria emission mixture for discharge lamps
Assignee: General Electric Co
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Filing: 1974-07-12
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Granted: 1975-11-11
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Expires: 1994-07-12
Abstract
Abstract An improved emission material particularly useful as a coating on the metallic electrodes of metal halide lamps consists of a solid solution of yttrium oxide in the thorium oxide lattice. Enhanced maintenance including less shifting of color rendition with life is achieved. Preferred proportions are 5 to 20 mole percent of YO3 in ThO2 prefired into a single-phase solid solution.
Inventors
- 👤 Ranajit K Datta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:44
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/04; H01J61/06; H01J61/073; H01J61/0735; H01J61/0737
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
53 words
AN ELECTRODE FOR AN ARC DISCHARGE DEVICE COMPRISING A REFRACTORY METAL SUBSTRATE AND AN ELECTRON EMISSIVE MATERIAL CARRIED THEREON COMPRISING A SOLID SOLUTION OF Y2O3 IN TH2 WHEREIN THE PROPORTION OF Y2O3 IS IN THE RANGE FROM A SMALL AMOUNT EFFECTIVE TO IMPROVE EMISSION CHARACTERISTICS UP TO ABOUT 50 MOLE PERCENT IN THO2.
Claim 2
Dependent Claim
53 words
AN ELECTRODE FOR AN ARC DISCHARGE DEVICE COMPRISING A REFRACTORY METAL SUBSTRATE AND AN ELECTRON EMISSIVE MATERIAL CARRIED THEREON COMPRISING A SOLID SOLUTION OF Y2O3 IN TH2 WHEREIN THE PROPORTION OF Y2O3 IS IN THE RANGE FROM A SMALL AMOUNT EFFECTIVE TO IMPROVE EMISSION CHARACTERISTICS UP TO ABOUT 50 MOLE PERCENT IN THO2.
Claim 3
Dependent Claim
23 words
An electrode as in claim 1 wherEin the proportion of Y2O3 is in the range from 5 to 20 mole percent in ThO2.
Claim 4
Dependent Claim
77 words
A high pressure electric discharge lamp comprising a light-transmitting envelope having refractory metal electrodes sealed into opposite ends and containing an ionizable medium including mercury, metal halide and an inert gas at low pressure, and an electron emissive material carried on said electrodes comprising a solid solution of Y2O3 in ThO2 wherein the proportion of Y2O3 is in the range from a small amount effective to improve emission characteristics up to about 50 mole percent in ThO2.
Claim 5
Dependent Claim
77 words
A high pressure electric discharge lamp comprising a light-transmitting envelope having refractory metal electrodes sealed into opposite ends and containing an ionizable medium including mercury, metal halide and an inert gas at low pressure, and an electron emissive material carried on said electrodes comprising a solid solution of Y2O3 in ThO2 wherein the proportion of Y2O3 is in the range from a small amount effective to improve emission characteristics up to about 50 mole percent in ThO2.
Claim 6
Dependent Claim
23 words
A lamp as in claim 3 wherein the proportion of Y2O3 is in the range from 5 to 20 mole percent in ThO2.
Claim 7
Dependent Claim
38 words
A lamp as in claim 3 wherein the refractory metal electrodes comprise turns of tungsten wire wound around a tungsten shank and the electron emissive material is coated on said turns and lodged in the interstices between turns.
Claim 8
Dependent Claim
23 words
A lamp as in claim 5 wherein the proportion of Y2O3 is in the range from 5 to 20 mole percent in ThO2.
Claim 9
Dependent Claim
16 words
A lamp as in claim 6 wherein the ionizable filling includes sodium, thallium and indium iodides.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |