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US5273681A
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Praseodymium-doped luminescent compositions
Assignee: General Electric Co
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Filing: 1992-06-22
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Granted: 1993-12-28
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Expires: 2012-06-22
Abstract
Abstract Phosphorescent compositions of the formula Pr x SrM 1-x AlO 4 , wherein M is lanthanum or gadolinium and x is in the range of about 0.025-0.075, are prepared by the reaction of appropriate proportions of aluminum nitrate, strontium carbonate, gadolinium(III) oxide or lanthanum(III) oxide and a praseodymium oxide. They emit light in the red and green regions of the visible spectrum.
Inventors
- 👤 Alok M. Srivastava
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:51
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7774
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
36 words
A luminescent crystalline composition having the formula Pr x SrM 1-x AlO 4 , wherein M is lanthanum or gadolinium and x is in the range of about 0.025-0.075, said composition having a tetragonal crystal lattice.
Claim 2
Dependent Claim
36 words
A luminescent crystalline composition having the formula Pr x SrM 1-x AlO 4 , wherein M is lanthanum or gadolinium and x is in the range of about 0.025-0.075, said composition having a tetragonal crystal lattice.
Claim 3
Dependent Claim
10 words
A composition according to claim 1 wherein M is lanthanum.
Claim 4
Dependent Claim
10 words
A composition according to claim 2 wherein x is 0.05.
Claim 5
Dependent Claim
10 words
A composition according to claim 1 wherein M is gadolinium.
Claim 6
Dependent Claim
10 words
A composition according to claim 4 wherein x is 0.05.
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) | 1996-12-27 | 1997-06-28 | 1997-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-27 | 2001-06-28 | 2001-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-27 | 2005-06-28 | 2005-12-28 | $7700.00 | Window Closed / Lapsed |