US3900754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric discharge lamp
Assignee: Thorn Lighting Ltd
•
Filing: 1974-01-18
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Granted: 1975-08-19
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Expires: 1994-01-18
Abstract
Abstract Electric discharge lamps of extended life can be produced or cheaper materials used in their manufacture by providing on the internal surface of the envelope and on the exposed surfaces of internal components a protective coating of a metal phosphate or arsenate glass. External surfaces can also be protected against corrosion in air or in the atmosphere within an outer jacket, where this is employed. The coating may be applied in a liquid medium which, preferably after draining, is warmed to evaporate the medium and thereafter baked to form the vitreous coating.
Inventors
- 👤 David Robert Mason
- 👤 Susan Margaret Cole
- 👤 Maurice Arthur Cayless
- 👤 David Osborn Wharmby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:09
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/30; H01J61/35; H01J17/00; H01J17/02; H01J17/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
82 words
AN ELECTRICAL DISCHARGE LAMP COMPRISING: AN ARC TUBE, COMPONENTS INCLUDING A PAIR OF SPACED ELECTRODES IN SAID ARC TUBE AND RESPECTIVE CONDUCTIVE LEADS OR SUPPORTS FOR SAID ELECTRODES, A GASEOUS FILL IN SAID TUBE, AND A TRANSPARENT, DEFECT-FREE, SOLUTION-DEPOSITED PROTECTIVE COATING OF A VITREOUS COMPOUND SELECTED FROM METAL PHOSPHATES AND ARSENATES ON AT LEAST THE INTERNAL SURFACE OF THE ARC TUBE AND THE EXPOSED SURFACES OF SAID LEADS OR SUPPORTS WHICH TEND TO REACT WITH SAID FILL DURING OPERATION OF THE LAMP.
Claim 2
Dependent Claim
82 words
AN ELECTRICAL DISCHARGE LAMP COMPRISING: AN ARC TUBE, COMPONENTS INCLUDING A PAIR OF SPACED ELECTRODES IN SAID ARC TUBE AND RESPECTIVE CONDUCTIVE LEADS OR SUPPORTS FOR SAID ELECTRODES, A GASEOUS FILL IN SAID TUBE, AND A TRANSPARENT, DEFECT-FREE, SOLUTION-DEPOSITED PROTECTIVE COATING OF A VITREOUS COMPOUND SELECTED FROM METAL PHOSPHATES AND ARSENATES ON AT LEAST THE INTERNAL SURFACE OF THE ARC TUBE AND THE EXPOSED SURFACES OF SAID LEADS OR SUPPORTS WHICH TEND TO REACT WITH SAID FILL DURING OPERATION OF THE LAMP.
Claim 3
Dependent Claim
27 words
A lamp according to claim 1 further comprising metallic end caps on said tube, the internal surface of said end caps being also provided with said coating.
Claim 4
Dependent Claim
30 words
A lamp according to claim 1 further comprising a coating of a metal phosphate or arsenate glass on the external surfaces of said arc tube and components of said lamp.
Claim 5
Dependent Claim
18 words
A lamp according to claim 3 further comprising a light-transmitting outer jacket enclosing said arc tube and components.
Claim 6
Dependent Claim
29 words
A lamp according to claim 1 wherein said coating comprises a phosphate or arsenate glass of at least one of the metals aluminium, iron, chromium, titanium, vanadium and tin.
Claim 7
Dependent Claim
16 words
A lamp according to claim 1 wherein said coating is composed of an aluminium phosphate glass.
Claim 8
Dependent Claim
25 words
A lamp according to claim 5 wherein the atomic ratio of metal to phosphorus or arsenic in the glass composition is from 1:0.1 to 1:2.9.
Claim 9
Dependent Claim
22 words
A lamp according to claim 1 wherein said coating is the deposited and baked residue of a solvent-soluble complex phosphate or arsenate.
Claim 10
Dependent Claim
32 words
A lamp according to claim 1 wherein said coating comprises the deposited and baked residue of a compound of said metal and an acid moiety selected from oxyacids of phosphorous or arsenic.
References Cited (Backward Citations)
US2030397A
Cited
US2393469A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |