US3867664A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric discharge devices
Assignee: EMI Group Ltd
•
Filing: 1974-01-21
•
Granted: 1975-02-18
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Expires: 1994-01-21
Abstract
Abstract The inclusion of an alkali metal halide in the gas fill of a high pressure mercury and aluminium halide discharge lamp improves the colour appearance of the lamp; notably by lowering the colour temperature, while maintaining or even increasing the efficacy and stability of the discharge. Preferred contents are 10 to 30 mg cm 3 mercury, 5 to 100 Mu mol cm 3 aluminium halide and 0.5 to 150 Mu mol cm 3 alkali metal halide, with the molar ratio of alkali metal halide to aluminium halide in the range 0.1 to 1.5 and the total number of aluminium and alkali metal atoms preferably greater than the total number of halogen atoms.
Inventors
- 👤 Alan George Chalmers
- 👤 David Osborn Wharmby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:25
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/12; H01J61/18
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
37 words
A HIGH-PRESSURE ELECTRICAL DISCHARGE LAMP COMPRISING: A LIGHT-TRANSMITTING DISCHARGE VESSEL; SPACED ELECTRODES IN SAID VESSEL; AND A GASS FILL IN SAID C VESSEL COMPRISING MERCURY VAPOUR, RARE GAS, ALUMINUM HALIDE AND AT LEAST ONE ALKALI METAL HALIDE.
Claim 2
Dependent Claim
37 words
A HIGH-PRESSURE ELECTRICAL DISCHARGE LAMP COMPRISING: A LIGHT-TRANSMITTING DISCHARGE VESSEL; SPACED ELECTRODES IN SAID VESSEL; AND A GASS FILL IN SAID C VESSEL COMPRISING MERCURY VAPOUR, RARE GAS, ALUMINUM HALIDE AND AT LEAST ONE ALKALI METAL HALIDE.
Claim 3
Dependent Claim
99 words
A high-pressure electrical discharge vessel comprising: a light-transmitting discharge vessel having a wall power loaded at between 10 and 100 Wcm 2 during operation; spaced electrodes in said vessel; and a gass fill in said vessel comprising a rare gas, mercury in the range 0 to 30 mg cm 3, an alkali metal halide and an aluminium halide, the alkali metal and aluminium halides being present in such quantities that the molar ratio of alkali metal halide to aluminium halide is from 0.1 to 1.5 and unevaporated aluminium and alkali metal halides are present during operation of the lamp.
Claim 4
Dependent Claim
99 words
A high-pressure electrical discharge vessel comprising: a light-transmitting discharge vessel having a wall power loaded at between 10 and 100 Wcm 2 during operation; spaced electrodes in said vessel; and a gass fill in said vessel comprising a rare gas, mercury in the range 0 to 30 mg cm 3, an alkali metal halide and an aluminium halide, the alkali metal and aluminium halides being present in such quantities that the molar ratio of alkali metal halide to aluminium halide is from 0.1 to 1.5 and unevaporated aluminium and alkali metal halides are present during operation of the lamp.
Claim 5
Dependent Claim
28 words
A discharge lamp as claimed in claim 2, in which the total number of aluminium and alkali metal atoms is greater than the total number of halogen atoms.
Claim 6
Dependent Claim
51 words
A discharge lamp according to claim 2 wherein said gas fill comprises mercry in the range 10 to 30 mg cm 3, aluminium chloride or iodide in the range 5 to 100 Mu mol cm 3 and sodium chloride or iodide in the range 0.5 to 150 Mu mol cm 3.
Claim 7
Dependent Claim
27 words
A discharge lamp according to claim 4 in which the total number of aluminium and alkali metal atoms is greater than the total number of halogen atoms.
References Cited (Backward Citations)
US3771009A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |