US5156885A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for encapsulating electroluminescent phosphor particles
Assignee: 3M Co
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Filing: 1990-04-25
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Granted: 1992-10-20
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Expires: 2010-04-25
Abstract
Abstract Encapsulated electroluminescent phosphor particles and method for making same. The phosphor particles are encapsulated in a very thin oxide layer to protect them from aging due to moisture intrusion. The particles are encapsulated via a vapor phase hydrolysis reaction of oxide precursor materials at a temperature of between about 25° C. and about 170° C., preferably between about 100° C. and about 150° C. The resultant encapsulated particles exhibit a surprising combination of high initial luminescent brightness and high resistance to humidity-accelerated brightness decay.
Inventors
- 👤 Kenton D. Budd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:58
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/442; C09; C09K; C09K11/00; C09K11/08; C09K11/70; C09K11/02; C09K11/025; C23C16/22; C23C16/30; C23C16/40; C23C16/405; Y; Y10; Y10S; Y10S428/00; Y10S428/917; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
83 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors such that said precursors chemically react via hydrolysis and condensation to form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 2
Dependent Claim
83 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors such that said precursors chemically react via hydrolysis and condensation to form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein said bed is heated to a temperature of between about 100° C. and about 150° C.
Claim 4
Dependent Claim
90 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors, said vapor phase oxide precursors comprising water vapor and titanium tetrachloride, such that said precursors chemically react and form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 5
Dependent Claim
90 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors, said vapor phase oxide precursors comprising water vapor and titanium tetrachloride, such that said precursors chemically react and form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 6
Dependent Claim
92 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors, said vapor phase oxide precursors comprising water vapor, titanium tetrachloride, and silicon tetrachloride, such that said precursors chemically react and form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 7
Dependent Claim
92 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors, said vapor phase oxide precursors comprising water vapor, titanium tetrachloride, and silicon tetrachloride, such that said precursors chemically react and form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 8
Dependent Claim
96 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors, said vapor phase oxide precursors comprising water vapor and one or more metal alkoxides or metal chlorides, such that said precursors chemically react and form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 9
Dependent Claim
96 words
A process for encapsulating phosphor particles in substantially transparent oxide coatings comprising: a) providing an agitated bed of phosphor particles; b) heating said bed to a temperature of between about 25° C. and about 170° C.; c) exposing said bed to one or more vapor phase oxide precursors, said vapor phase oxide precursors comprising water vapor and one or more metal alkoxides or metal chlorides, such that said precursors chemically react and form hermetic, substantially transparent oxide coatings on the surfaces of said particles, thereby yielding essentially encapsulated phosphor particles; and d) cooling said encapsulated particles.
Claim 10
Dependent Claim
14 words
The process of claim 1 wherein said phosphor particles comprise zinc sulfide-based phosphor materials.
Claim 11
Dependent Claim
26 words
The process of claim 1 wherein said particles contain minor amounts of one or more of the following: cadmium, selenium, copper, bromine, chlorine, manganese, or silver.
Claim 12
Dependent Claim
19 words
The process of claim 1 wherein said phosphor particles are between about 1 and about 50 microns in diameter.
Claim 13
Dependent Claim
19 words
The process of claim 1 wherein said phosphor particles are between about 10 and about 40 microns in diameter.
Claim 14
Dependent Claim
18 words
The process of claim 1 wherein said oxide coatings are between about 0.1 and about 3.0 microns thick.
Claim 15
Dependent Claim
18 words
The process of claim 1 wherein said oxide coatings are between about 0.1 and about 0.5 microns thick.
References Cited (Backward Citations)
US3264133A
Cited
US3306768A
Cited
US4097776A
Cited
US4508760A
Cited
EP0160856A2
Cited
US4585673A
Cited
US4690832A
Cited
JPS62177087A
Cited
JPS63318092A
Cited
US4855189A
Cited
US4990371A
Cited
US4999219A
Cited
WO1991010715A1
Cited
EP0462504A2
Cited
US5080928A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-20 | 1996-04-20 | 1996-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-20 | 2000-04-20 | 2000-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-20 | 2004-04-20 | 2004-10-20 | $7700.00 | Window Closed / Lapsed |