US4166234A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluorescent discharge lamp having luminescent material of a specified grain size
Assignee: US Philips Corp
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Filing: 1978-02-28
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Granted: 1979-08-28
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Expires: 1998-02-28
Abstract
Abstract A low-pressure mercury vapor discharge lamp provided with a luminescent Eu-activated rare earth oxide, a luminescent aluminate with hexagonal crystal structure activated by Ce or by Ce and Tb, or a luminescent aluminate with hexagonal crystal structure activated by Eu or by Eu and Mn. Not more than 5% by weight of the luminescent material has a grain size smaller than 1 μm and the maximum of the grain size distribution curve is located in the range from 2 to 8 μm.
Inventors
- 👤 Marinus G. A. Tak
- 👤 Robert C. Peters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:16
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7783; C09K11/7784; C09K11/7766; C09K11/7774; H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/42; H01J61/44
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
118 words
A low pressure mercury vapour discharge lamp provided with a luminescent coating which comprises at least one luminescent material from the group of rare earth oxides activated by trivalent europium, the rare-earth-magnesium-aluminates with hexagonal crystal structure, activated by cerium or by cerium and terbium, and the alkaline earth-magnesium-aluminates with hexagonal crystal structure activated by bivalent europium or by bivalent europium and by bivalent manganese, which luminescent material consists of a fine-grain material, characterized in that not more than 5 wt.% of the luminescent material has a grain size smaller than 1 μm and that the maximum of the grain size distribution curve of the luminescent material is located in the grain size range from 2 to 8 μm.
Claim 2
Dependent Claim
118 words
A low pressure mercury vapour discharge lamp provided with a luminescent coating which comprises at least one luminescent material from the group of rare earth oxides activated by trivalent europium, the rare-earth-magnesium-aluminates with hexagonal crystal structure, activated by cerium or by cerium and terbium, and the alkaline earth-magnesium-aluminates with hexagonal crystal structure activated by bivalent europium or by bivalent europium and by bivalent manganese, which luminescent material consists of a fine-grain material, characterized in that not more than 5 wt.% of the luminescent material has a grain size smaller than 1 μm and that the maximum of the grain size distribution curve of the luminescent material is located in the grain size range from 2 to 8 μm.
Claim 3
Dependent Claim
32 words
A low-pressure mercury vapour discharge lamp as claimed in claim 1, characterized in that not more than 1% by weight of the luminescent material has a grain size smaller than 1 μm.
Claim 4
Dependent Claim
33 words
A low-pressure mercury vapour discharge lamp as claimed in claim 1 or 2, characterized in that not more than 25% by weight of the luminescent material has a grain size over 15 μm.
Claim 5
Dependent Claim
38 words
A low-pressure mercury vapour discharge lamp as claimed in claim 1 characterized in that the maximum of the grain size distribution curve of the luminescent material is located in the grain size range from 2 to 4 μm.
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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) | 1982-08-27 | 1983-02-26 | 1983-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-27 | 1987-02-26 | 1987-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-27 | 1991-02-26 | 1991-08-28 | $7700.00 | Window Closed / Lapsed |