Patent US4099080A successfully refreshed from Google Patents.
US4099080A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Incandescent lamp with improved coating and method
Assignee: Philips North America LLC
•
Filing: 1977-03-31
•
Granted: 1978-07-04
•
Expires: 1997-03-31
Abstract
Abstract This invention relates to an incandescent lamp having an improved light diffusing coating carried on the internal surface of the lamp envelope and a method for applying the coating. The coating is a mixture of very finely divided, very low-moisture content powders. The powders substantially comprise a mixture of hydrophilic silica and hydrophobic silica. This coating has been found to be very adherent and substantially free from agglomerations of the silica.
Inventors
- 👤 Chester W. Dawson
- 👤 Robert B. Parsons
- 👤 Douglas M. Mattox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:14
CPC Classifications
H; H01; H01K; H01K1/00; H01K1/28; H01K1/32
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
61 words
An incandescent lamp having a light-transmitting envelope and carrying on the internal surface of said envelope a thin light-diffusing coating substantially comprising a mixture of very finely divided silica powders, said silica powders being a mixture of of from about 40% to about 99.5% by weight hydrophilic silica having less than 4% moisture loss on ignition and the balance hydrophobic silica.
Claim 2
Dependent Claim
61 words
An incandescent lamp having a light-transmitting envelope and carrying on the internal surface of said envelope a thin light-diffusing coating substantially comprising a mixture of very finely divided silica powders, said silica powders being a mixture of of from about 40% to about 99.5% by weight hydrophilic silica having less than 4% moisture loss on ignition and the balance hydrophobic silica.
Claim 3
Dependent Claim
33 words
The lamp of claim 1, wherein said hydrophilic silica powder has an average particle diameter of at least 40 nm and an average surface area of less than about 65 m 2 /g.
Claim 4
Dependent Claim
18 words
The lamp of claim 2, wherein said thin light-diffusing coating includes finely divided titania as an adhesion promoter.
Claim 5
Dependent Claim
49 words
The lamp of claim 3, wherein said hydrophilic silica powder is from about 40 to 95 wt.% of said thin light-diffusing coating, said hydrophobic silica powder is from about 10 to 40 wt.% of said coating, and said titania is from about 5 to 40 wt.% of said coating.
Claim 6
Dependent Claim
24 words
The lamp of claim 4, wherein said thin light-diffusing coating is 70% hydrophilic silica powder, 20% finely divided titania, and 10% hydrophobic silica powder.
Claim 7
Dependent Claim
33 words
The lamp of claim 1, wherein said hydrophilic silica powder has an average particle diameter of less than about 25 nm and an average surface area of at least 100 m 2 /g.
Claim 8
Dependent Claim
37 words
The lamp of claim 6, wherein said hydrophilic silica powder is from about 70 to 99.5 wt.% of said thin light-diffusing coating and said hydrophobic silica powder is from about 0.5 to 30 wt.% of said coating.
Claim 9
Dependent Claim
29 words
The lamp of claim 7, wherein said hydrophilic silica powder is 90 wt.% of said thin light-diffusing coating and said hydrophobic silica powder is 10 wt.% of said coating.
Claim 10
Independent Claim
165 words
The method of electrostatically coating the inner surface of an incandescent lamp envelope with a thin layer substantially comprising very low-moisture content, very finely-divided silica to provide a coating which is very adherent and is substantially free from agglomerations of said silica, which method comprises: a. forming a composition comprising a finely divided mixture of from about 40% to about 99.5% by weight hydrophilic and the balance hydrophobic silica powders, and maintaining said mixture free from additional moisture until ready for coating; b. heating said envelope to be coated to render same electrically conductive; and c. introducing through a diffusing nozzle and into the interior of said envelope to be coated a smoke of said mixed hydrophobic silica and low-moisture content hydrophobic silica and applying an intense electric field between a location interiorly of said envelope to be coated and the conductive surface thereof to cause the silica of said smoke to deposit as a thin layer onto the interior surface of said lamp envelope.
Claim 11
Independent Claim
165 words
The method of electrostatically coating the inner surface of an incandescent lamp envelope with a thin layer substantially comprising very low-moisture content, very finely-divided silica to provide a coating which is very adherent and is substantially free from agglomerations of said silica, which method comprises: a. forming a composition comprising a finely divided mixture of from about 40% to about 99.5% by weight hydrophilic and the balance hydrophobic silica powders, and maintaining said mixture free from additional moisture until ready for coating; b. heating said envelope to be coated to render same electrically conductive; and c. introducing through a diffusing nozzle and into the interior of said envelope to be coated a smoke of said mixed hydrophobic silica and low-moisture content hydrophobic silica and applying an intense electric field between a location interiorly of said envelope to be coated and the conductive surface thereof to cause the silica of said smoke to deposit as a thin layer onto the interior surface of said lamp envelope.
Claim 12
Dependent Claim
20 words
The method of claim 9, wherein said lamp envelope is heated to about 100° C. with gas burning heater units.
Claim 13
Dependent Claim
22 words
The method of claim 10, wherein said smoke is introduced into said envelope through a number of orifices disposed on said nozzle.
Claim 14
Dependent Claim
29 words
The method of claim 11, wherein said electric field is produced by a high voltage, direct current source electrically connected between said gas burning heater units and said nozzle.
References Cited (Backward Citations)
US3125457A
Cited
US2545896A
Cited
US2661438A
Cited
US2963611A
Cited
US2888354A
Cited
US2922065A
Cited
US2921827A
Cited
US2988458A
Cited
FR2224873A1
Cited
US3961600A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |