US5126166A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of reducing the degradation of the red phosphor, Y203:EU, in water base lamp suspensions
Assignee: Osram Sylvania Inc
•
Filing: 1990-12-21
•
Granted: 1992-06-30
•
Expires: 2010-12-21
Abstract
Abstract A method has been found which reduces substantially the degradation of the red phosphor, Y 2 O 3 :Eu, in water base fluorescent lamp suspension, thereby prolonging the shelf life of triphosphor suspensions. The method of the invention comprises forming a protective coating around individual particles of europium-doped yttrium oxide phosphor to inhibit degradation of europium-doped yttrium oxide phosphor in a water base phosphor coating suspension, the protective coating comprising an inorganic material and being of sufficient thickness to prevent the europium-doped yttrium oxide phosphor from reacting with the coating suspension. A preferred coating material is gamma-alumina.
Inventors
- 👤 Arunava Dutta
- 👤 Ernest A. Dale
- 👤 Leonard V. Dullea
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:25
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/02; C09K11/025; C09K11/08; C09K11/77; C09K11/7783; C09K11/7784; C09K11/7787; H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/42; H01J61/46
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
99 words
A method of reducing the degradation of Y 2 O 3 :Eu phosphor in water base fluorescent lamp coating suspensions comprising: forming a protective coating around individual particles of europium-doped yttrium oxide phosphor to inhibit degradation of europium-doped yttrium oxide phosphor in a water base phosphor coating suspension, the protective coating comprising silicon oxynitride of sufficient thickness to prevent the europium-doped yttrium oxide phosphor from reacting with said water base phosphor coating suspension, said silicon oxynitride protective coating having a solubility in water of less than 0.0001 grams/cc at 25° C. at pH from about 6 to about 10.
Claim 2
Independent Claim
99 words
A method of reducing the degradation of Y 2 O 3 :Eu phosphor in water base fluorescent lamp coating suspensions comprising: forming a protective coating around individual particles of europium-doped yttrium oxide phosphor to inhibit degradation of europium-doped yttrium oxide phosphor in a water base phosphor coating suspension, the protective coating comprising silicon oxynitride of sufficient thickness to prevent the europium-doped yttrium oxide phosphor from reacting with said water base phosphor coating suspension, said silicon oxynitride protective coating having a solubility in water of less than 0.0001 grams/cc at 25° C. at pH from about 6 to about 10.
Claim 3
Independent Claim
87 words
A method of reducing the degradation of Y 2 O 3 :Eu phosphor in water base fluorescent lamp coating suspensions comprising: forming a protective coating around individual particles of europium-doped yttrium oxide phosphor to inhibit degradation of europium-doped yttrium oxide phosphor in a water base phosphor coating suspension, the protective coating comprising silicon oxynitride of sufficient thickness to prevent the europium-doped yttrium oxide suspension wherein said silicon oxynitride protective coating has a lower aqueous solubility than yttrium hydroxide over a range of pH from 6 to 10.
Claim 4
Independent Claim
87 words
A method of reducing the degradation of Y 2 O 3 :Eu phosphor in water base fluorescent lamp coating suspensions comprising: forming a protective coating around individual particles of europium-doped yttrium oxide phosphor to inhibit degradation of europium-doped yttrium oxide phosphor in a water base phosphor coating suspension, the protective coating comprising silicon oxynitride of sufficient thickness to prevent the europium-doped yttrium oxide suspension wherein said silicon oxynitride protective coating has a lower aqueous solubility than yttrium hydroxide over a range of pH from 6 to 10.
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) | 1995-06-30 | 1995-12-30 | 1996-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-30 | 1999-12-30 | 2000-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-30 | 2003-12-30 | 2004-06-30 | $7700.00 | Window Closed / Lapsed |