Patent US5695685A successfully refreshed from Google Patents.
US5695685A
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Phosphor with modified surface composition and method for preparation
Assignee: Ledvance LLC
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Filing: 1997-01-03
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Granted: 1997-12-09
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Expires: 2017-01-03
Abstract
Abstract A surface modified phosphor powder exhibiting increased lumen maintenance. At the outer surface of each phosphor particle, the cations of the phosphor material have been replaced by other cations, e.g., a metal or metalloid cation such as aluminum, barium, calcium, lanthanum, magnesium, strontium, yttrium, zinc, titanium, tantalum, boron, or silicon. The phosphor powder is chemically modified by forming a suspension of phosphor particles in a liquid medium including the metal or metalloid ions in solution. The phosphor suspension is stirred for a time sufficient to permit an ion exchange reaction in which the metal or metalloid ions are substituted for cations of the phosphor to form a layer of the desired metal or metalloid compound at the phosphor outer surface.
Inventors
- 👤 Chung Nin Chau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:27
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/42; H01J61/44; C; C09; C09K; C09K11/00; C09K11/02; C09K11/025; C09K11/08
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
34 words
A method for chemically modifying the composition of outer surfaces of particles of a phosphor, said method comprising substituting selected cations for cations of said phosphor at said surfaces by an ion exchange reaction.
Claim 2
Independent Claim
34 words
A method for chemically modifying the composition of outer surfaces of particles of a phosphor, said method comprising substituting selected cations for cations of said phosphor at said surfaces by an ion exchange reaction.
Claim 3
Dependent Claim
22 words
A method in accordance with claim 1 wherein said reaction takes place in a liquid medium containing said selected cations in solution.
Claim 4
Dependent Claim
15 words
A method in accordance with claim 2 wherein said liquid medium is an aqueous medium.
Claim 5
Dependent Claim
23 words
A method in accordance with claim 2 wherein said selected cations are ions of a metal or metalloid different from said phosphor cations.
Claim 6
Dependent Claim
32 words
A method in accordance with claim 4 wherein said metal or metalloid is selected from the group consisting of aluminum, barium, calcium, lanthanum, magnesium, strontium, yttrium, zinc, titanium, tantalum, boron, and silicon.
Claim 7
Dependent Claim
37 words
A method in accordance with claim 5 wherein said metal or metalloid ions are provided by a water soluble salt selected from the group consisting of acetates, halides, formates, lactates, and nitrates of said metal or metalloid.
Claim 8
Dependent Claim
82 words
A method in accordance with claim 4 wherein said cation substitution comprises: forming a suspension of said phosphor particles in said liquid medium, said liquid medium including said metal or metalloid ions in solution; stirring said phosphor suspension for a time sufficient to permit an ion exchange reaction in which said metal or metalloid ions are substituted for cations of said phosphor to form a layer comprising a compound of said metal or metalloid at an outer surface of said phosphor particles.
Claim 9
Dependent Claim
29 words
A method in accordance with claim 7 further comprising: filtering said particles out of said suspension; and drying said particles to produce phosphor particles having a modified surface composition.
Claim 10
Dependent Claim
67 words
A method in accordance with claim 7 wherein said metal or metalloid ions are provided by a water soluble salt selected from the group consisting of acetates, halides, formates, lactates, and nitrates of said metal or metalloid, and the amount of said metal or metalloid salt in said liquid medium is about 0.5-1.5 percent by weight, based on the weight of phosphor suspended in said liquid medium.
Claim 11
Independent Claim
171 words
A method for improving lumen maintenance of a lamp comprising: forming a first suspension of particles of a phosphor in a liquid medium including cations of a metal or metalloid, said metal or metalloid being different from that of which said phosphor is a compound; stirring said first suspension for a time sufficient to permit an ion exchange reaction in which said metal or metalloid cations are substituted for cations of said phosphor at the phosphor particle outer surfaces to produce phosphor particles having a modified surface composition; coating an interior surface of a lamp envelope with a layer of a second suspension comprising said modified particles suspended in a solution comprising a binder and an aqueous medium; drying said phosphor layer sufficiently to adhere said phosphor layer to said lamp envelope surface; and lehring said lamp envelope to burn out said binder and to produce a coating of phosphor particles on said lamp envelope, each particle having a layer comprising a compound of said metal or metalloid on its surface.
Claim 12
Independent Claim
171 words
A method for improving lumen maintenance of a lamp comprising: forming a first suspension of particles of a phosphor in a liquid medium including cations of a metal or metalloid, said metal or metalloid being different from that of which said phosphor is a compound; stirring said first suspension for a time sufficient to permit an ion exchange reaction in which said metal or metalloid cations are substituted for cations of said phosphor at the phosphor particle outer surfaces to produce phosphor particles having a modified surface composition; coating an interior surface of a lamp envelope with a layer of a second suspension comprising said modified particles suspended in a solution comprising a binder and an aqueous medium; drying said phosphor layer sufficiently to adhere said phosphor layer to said lamp envelope surface; and lehring said lamp envelope to burn out said binder and to produce a coating of phosphor particles on said lamp envelope, each particle having a layer comprising a compound of said metal or metalloid on its surface.
Claim 13
Dependent Claim
42 words
A method in accordance with claim 10 further comprising: filtering said phosphor particles out of said first suspension; drying said particles to produce said modified phosphor particles; and forming said second suspension by suspending said modified particles in said binder/aqueous medium solution.
Claim 14
Dependent Claim
15 words
A method in accordance with claim 10 wherein said liquid medium is an aqueous medium.
Claim 15
Dependent Claim
31 words
A method in accordance with claim 10 wherein said metal or metalloid is selected from the group including aluminum, barium, calcium, lanthanum, magnesium, strontium, yttrium, zinc, titanium, tantalum, boron, and silicon.
Claim 16
Dependent Claim
38 words
A method in accordance with claim 13 wherein said metal or metalloid ions are provided by a water soluble salt selected from the group consisting of acetates, bromides, formates, halides, lactates, and nitrates of said metal or metalloid.
Claim 17
Dependent Claim
37 words
A method in accordance with claim 14 wherein the amount of said metal or metalloid salt in said liquid medium is about 0.5-1.5 percent by weight, based on the weight of phosphor suspended in said liquid medium.
Claim 18
Dependent Claim
39 words
A phosphor powder comprising individual particles of a phosphor material, an outer surface of each of said particles being a layer in which cations of said phosphor material have been replaced by cations different from said phosphor material cations.
Claim 19
Dependent Claim
39 words
A phosphor powder comprising individual particles of a phosphor material, an outer surface of each of said particles being a layer in which cations of said phosphor material have been replaced by cations different from said phosphor material cations.
Claim 20
Dependent Claim
19 words
A phosphor powder in accordance with claim 16 wherein said different cations are ions of a metal or metalloid.
Claim 21
Dependent Claim
32 words
A phosphor powder in accordance with claim 17 wherein said metal or metalloid is selected from the group including aluminum, barium, calcium, lanthanum, magnesium, strontium, yttrium, zinc, titanium, tantalum, boron, and silicon.
Claim 22
Dependent Claim
70 words
A phosphor-coating composition for coating an inner surface of a lamp envelope, said composition comprising a suspension of a phosphor powder in a solution comprising a binder and an aqueous medium, said phosphor powder comprising individual particles of a phosphor material, an outer surface of each of said particles being a layer in which cations of said phosphor material have been replaced by cations different from said phosphor material cations.
Claim 23
Dependent Claim
70 words
A phosphor-coating composition for coating an inner surface of a lamp envelope, said composition comprising a suspension of a phosphor powder in a solution comprising a binder and an aqueous medium, said phosphor powder comprising individual particles of a phosphor material, an outer surface of each of said particles being a layer in which cations of said phosphor material have been replaced by cations different from said phosphor material cations.
Claim 24
Dependent Claim
19 words
A phosphor-coating composition in accordance with claim 19 wherein said different cations are ions of a metal or metalloid.
Claim 25
Dependent Claim
32 words
A phosphor-coating composition in accordance with claim 20 wherein said metal or metalloid is selected from the group including aluminum, barium, calcium, lanthanum, magnesium, strontium, yttrium, zinc, titanium, tantalum, boron, and silicon.
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| 3.5 Years (Year 4) | 2000-12-08 | 2001-06-09 | 2001-12-09 | $2000.00 | Window Closed / Lapsed |
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