US3748518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluorescent lamp having titania-doped glass envelope with transparent buffer film of titania
Assignee: Philips North America LLC
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Filing: 1972-06-14
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Granted: 1973-07-24
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Expires: 1992-06-14
Abstract
Abstract The light output and lumen maintenance of a fluorescent lamp having a bulb composed of soda-lime silicate glass are enhanced by doping the glass with a controlled amount of titania and vapor-depositing a thin transparent film of TiO2 on the inner surface of the bulb at the phosphor-glass interface. The titania film has a thickness of from 0.01 to 0.02 micron and serves as a ''''buffer layer'''' which, reflects ultraviolet radiation and, in conjunction with the titania in the glass, thus inhibits the solarization of the bulb and deleterious chemical reactions at the bulb surface. Optimum lamp performance is thus obtained with a minimum amount of titania.
Inventors
- 👤 D Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:57
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/30; H01J61/35
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
35 words
The electric discharge lamp of claim 1 wherein; said envelope is of tubular configuration, and said film of TiO2 is coated with a layer of ultraviolet-responsive phosphor and the lamp thus comprises a fluorescent lamp.
Claim 2
Dependent Claim
21 words
The fluorescent lamp of claim 2 wherein said lamp also has an adherent transparent film of TiO2 on its outer surface.
Claim 3
Dependent Claim
39 words
The fluorescent lamp of claim 2 wherein the TiO2 content of said glass envelope is within a range of from about 0.5 to 1.5 percent by weight and the glass contains less than about 0.07 percent by weight Fe2O3.
Claim 4
Dependent Claim
37 words
The fluorescent lamp of claim 2 wherein; said film of TiO2 has a thickness of from about 0.011 to 0.018 micron, and said phosphor is of a type that is deleteriously affected by sodium and sodium ions.
Claim 5
Dependent Claim
46 words
The fluorescent lamp of claim 5 wherein; said phosphor comprises calcium halophosphate phosphor activated by antimony and manganese, the envelope glass contains from about 0.8 to 1.25 percent by weight TiO2, and said film of TiO2 has a thickness of from about 0.012 to 0.016 micron.
Claim 6
Dependent Claim
44 words
An envelope for a low-pressure electric discharge lamp comprising a tube of soda-lime silicate glass that contains from about 0.5 to 2 percent by weight TiO2 and has an adherent transparent film of TiO2 from 0.01 to 0.02 micron thick on its inner surface.
Claim 7
Dependent Claim
22 words
The lamp envelope of claim 7 wherein said glass tube also has an adherent transparent film of TiO2 on its outer surface.
Claim 8
Dependent Claim
37 words
The lamp envelope of claim 7 wherein the TiO2 content of the glass is between about 0.5 and 1.5 percent by weight and the film of TiO2 has a thickness of from about 0.011 to 0.018 micron.
Claim 9
Dependent Claim
21 words
The lamp envelope of claim 7 wherein the film of TiO2 has a thickness of from about 0.012 to 0.016 micron.
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) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |