Patent US4547700A successfully refreshed from Google Patents.
US4547700A
Expired / Lapsed
US
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Fluorescent lamp with homogeneous dispersion of alumina particles in phosphor layer
Assignee: Osram Sylvania Inc
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Filing: 1984-02-23
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Granted: 1985-10-15
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Expires: 2004-02-23
Abstract
Abstract Lumen maintenance in fluorescent lamps employing plural phosphor layers is improved by including alumina in the second layer; i.e., the layer closest to the discharge.
Inventors
- 👤 Geraldine A. Landry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:09
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/42; H01J61/46
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
97 words
In a fluorescent lamp having a light transmissive glass envelope containing an arc generating and sustaining medium including mercury and having electrodes sealed into the ends thereof, said envelope having on its interior a first layer of a substantially broad-band emitting phosphor and a second layer of phosphor comprised of a mixture of three substantially narrow band emitting phosphors, the improvement comprising: said second layer of said phosphor including a substantially homogeneous dispersion of sub-micron size particles of alumina in an amount of from about 6 to about 50 percent by weight of said second phosphor layer.
Claim 2
Dependent Claim
97 words
In a fluorescent lamp having a light transmissive glass envelope containing an arc generating and sustaining medium including mercury and having electrodes sealed into the ends thereof, said envelope having on its interior a first layer of a substantially broad-band emitting phosphor and a second layer of phosphor comprised of a mixture of three substantially narrow band emitting phosphors, the improvement comprising: said second layer of said phosphor including a substantially homogeneous dispersion of sub-micron size particles of alumina in an amount of from about 6 to about 50 percent by weight of said second phosphor layer.
Claim 3
Dependent Claim
18 words
The lamp of claim 1 wherein said alumina comprises about 40 weight percent of said second phosphor layer.
Claim 4
Dependent Claim
21 words
The lamp of claim 2 wherein said alumina has a particle size range of from about 0.01 to about 0.04 microns.
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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) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |