US4710677A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Incandescent lamps
Assignee: EMI Group Ltd
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Filing: 1984-08-02
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Granted: 1987-12-01
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Expires: 2004-08-02
Abstract
Abstract An incandescent lamp, which emits infra-red radiation, comprises a tubular quartz envelope, within which a tungsten filament is supported. To reflect radiation, which is emitted in a downward direction from the filament, back in an upward direction to an item to be heated, a substantially pure aluminum oxide coating is bonded in a substantially permanent manner to the surface of the envelope. The coating extends subtantially along the length of the lamp and around approximately half of the cross-sectional circumference thereof. The coating is applied to the envelope by a spray gun technique, wherein finely divided aluminum powder is blown through an oxygenated flame, which is directed towards an area of the envelope to be coated.
Inventors
- 👤 Alex L. Halberstadt
- 👤 Roger A. Hume
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:16
CPC Classifications
H; H01; H01K; H01K1/00; H01K1/28; H01K1/32; H01K1/325; H01J; H01J9/00; H01J9/20
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
138 words
An incandescent lamp comprising: an envelope having an exterior surface and being formed from a material having a substantially high silica content; a filament enclosed within said envelope; and a coating reflective of radiation emitted by said filament and consisting of a layer of a substantially pure metallic oxide containing no binding agent, said layer having been applied whilst in a molten state to an area of said exterior surface, thereby causing said layer to be fused in a substantially permanent manner to said exterior surface without a binding agent, so that, when heated by radiation from said filament, said coating undergoes substantially no discoloration, and wherein said coating possesses a variable thickness which is a maximum in a central region of said area of said exterior surface and a minimum in a peripheral region of said area.
Claim 2
Dependent Claim
138 words
An incandescent lamp comprising: an envelope having an exterior surface and being formed from a material having a substantially high silica content; a filament enclosed within said envelope; and a coating reflective of radiation emitted by said filament and consisting of a layer of a substantially pure metallic oxide containing no binding agent, said layer having been applied whilst in a molten state to an area of said exterior surface, thereby causing said layer to be fused in a substantially permanent manner to said exterior surface without a binding agent, so that, when heated by radiation from said filament, said coating undergoes substantially no discoloration, and wherein said coating possesses a variable thickness which is a maximum in a central region of said area of said exterior surface and a minimum in a peripheral region of said area.
Claim 3
Dependent Claim
16 words
A lamp as claimed in claim 1 wherein said substantially pure metal oxide is aluminium oxide.
Claim 4
Dependent Claim
12 words
A lamp as claimed in claim 1 wherein said material is quartz.
Claim 5
Dependent Claim
18 words
A lamp as claimed in claim 1, wherein said lamp is a tungsten-halogen lamp which emits infra-red radiation.
Claim 6
Dependent Claim
32 words
A lamp as claimed in claim 1, wherein said lamp is a generally tubular shape, said area extending substantially along the length thereof and around substantially half of the cross-sectional circumference thereof.
Claim 7
Dependent Claim
43 words
A lamp as claimed in claim 1, wherein each end of said lamp consists of a pinch seal with an electrical connection to the respective end of said filament sealed therein, said area including regions of said envelope adjacent to said pinch seals.
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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) | 1990-11-30 | 1991-06-01 | 1991-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-30 | 1995-06-01 | 1995-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-30 | 1999-06-01 | 1999-12-01 | $7700.00 | Window Closed / Lapsed |