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US3617332A
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US
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Method for stabilizing alkaline-earth metal sulfide phosphors
Assignee: Philips North America LLC
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Filing: 1969-06-24
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Granted: 1971-11-02
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Expires: 1989-06-24
Abstract
Abstract Method for stabilizing finely divided phosphors which have an alkaline-earth metal sulfide matrix wherein the phosphor is exposed to a solution of fluoride compound which reacts with the surface portion of the phosphor. Thereafter, the residual solution is separated from the phosphor. The resulting stabilized phosphor has particular utility for cathodoluminescent application such as cathode-ray tubes, and it can also be used in photoluminescent applications, such as lamps.
Inventors
- 👤 Willi Lehmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:05
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/0805; C09K11/0816; Y; Y10; Y10S; Y10S428/00; Y10S428/917
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
42 words
The method as specified in claim 1, wherein said solution is an aqueous solution, said solution is at about normal room temperature, and said phosphor is exposed to said solution for a period of from about 10 seconds to about 30 minutes.
Claim 2
Dependent Claim
25 words
The method as specified in claim 2, wherein said fluoride compound is one or more of ammonium fluoride, sodium fluoride, potassium fluoride, or lithium fluoride.
Claim 3
Dependent Claim
28 words
The method as specified in claim 3, wherein said fluoride compound is present in amount of from about 1 percent to 5 percent by weight of said solution.
Claim 4
Dependent Claim
32 words
The method as specified in claim 4, wherein said phosphor is present in said solution as a slurry in amount of from about 5 to 25 percent by weight of said solution.
Claim 5
Dependent Claim
35 words
The method as specified in claim 5, wherein said phosphor is one of cerium-activated calcium sulfide, manganese-activated strontium sulfide, europium-activated calcium sulfide, lead-activated calcium sulfide, bismuth-activated calcium sulfide, gold-activated barium sulfide, or europium-activated magnesium sulfide.
Claim 6
Dependent Claim
91 words
The method as specified in claim 6 wherein said phosphor is initially exposed to said aqueous solution of fluoride compound by being suspended in said solution along with a small amount of inorganic binder material to form a cOating slurry, said coating slurry is positioned over and in contact with a vitreous substrate to be phosphor coated, said phosphor is exposed to said solution as it settles therefrom onto said substrate, and after said phosphor has settled onto and coated said substrate, the residual solution is separated from said coated phosphor.
Claim 7
Dependent Claim
33 words
The method as specified in claim 7, wherein said inorganic binder material is sodium silicate or potassium silicate in amount of from about 1 percent to 2 percent by weight of said solution.
Claim 8
Dependent Claim
76 words
A vitreous substrate which is coated with a finely divided phosphor having an alkaline-earth metal sulfide matrix, said phosphor having been stabilized against reaction either with water or with high-temperature air by exposing said phosphor, either prior to or during substrate coating of same, to a solution of fluoride compound for a predetermined time sufficient to permit said fluoride to react with the surface of said phosphor, and residual solution thereafter being separated from said phosphor.
Claim 9
Dependent Claim
86 words
The vitreous substrate as specified in claim 9, wherein said solution of fluoride compound is at about room temperature and contains from 1 percent to 5 percent by weight of said solution of one or more of ammonium fluoride, sodium fluoride, potassium fluoride or lithium fluoride, said phosphor is present as a slurry in said solution in amount of from 5 percent to 25 percent by weight of said solution, and said phosphor is exposed to said solution for about 10 seconds to about 30 minutes.
References Cited (Backward Citations)
US3264133A
Cited
US3435271A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |