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US4264677A
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Red colored phosphor and process for preparing the same
Assignee: Mitsubishi Chemical Corp
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Filing: 1979-02-02
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Granted: 1981-04-28
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Expires: 1999-02-02
Abstract
Abstract An europium activated oxysulfide phosphor represented by the formula Ln.sub.2 O.sub.2 S:Eu,(Sm) wherein Ln is at least one element selected from the group consisting of yttrium, gadolinium, lanthanum, lutetium and scandium is colored into red by mixing therewith a proper amount of calcium salt solely or together with strontium salt, and firing the resulting mixture at a temperature within the range of 1000° to 1500° C. By the firing, a CaS:Eu,(Sm) phosphor or a (Ca,Sr)S:Eu,(Sm) phosphor having a red body color is produced in an external portion of the Ln 2 O 2 S:Eu,(Sm) phosphor particle. The red colored phosphor thus obtained is used as a red emitting phosphor of a high contrast cathode ray tube for color television.
Inventors
- 👤 Kazuo Koyama
- 👤 Takashi Miyagawa
- 👤 Michio Mathuyuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:51
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7783; C09K11/7784; C09K11/7786; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
93 words
A particulate red colored phosphor that is red emitting under cathode ray excitation comprising an internal portion consisting of an europium and optionally, samarium activated oxysulfide phosphor represented by the formula Ln.sub.2 O.sub.2 S:Eu, (Sm) wherein Ln is at least at one element selected from the group consisting of yttrium, gadolinium, lanthanum, lutetium and scandium, and an external portion consisting essentially of an europium and optionally, samarium activated sulfide red colored phosphor represented by the formula (Ca 1-x , Sr x )S:Eu, (Sm) wherein x is a number within the range of 0≦x≦0.75.
Claim 2
Dependent Claim
93 words
A particulate red colored phosphor that is red emitting under cathode ray excitation comprising an internal portion consisting of an europium and optionally, samarium activated oxysulfide phosphor represented by the formula Ln.sub.2 O.sub.2 S:Eu, (Sm) wherein Ln is at least at one element selected from the group consisting of yttrium, gadolinium, lanthanum, lutetium and scandium, and an external portion consisting essentially of an europium and optionally, samarium activated sulfide red colored phosphor represented by the formula (Ca 1-x , Sr x )S:Eu, (Sm) wherein x is a number within the range of 0≦x≦0.75.
Claim 3
Dependent Claim
20 words
A red colored phosphor as defined in claim 1 wherein said x is a number within the range of 0≦x≦0.5.
Claim 4
Dependent Claim
127 words
A process for preparing a red colored phosphor comprising steps of mixing europium and optionally, samarium activated oxysulfide red emitting under cathode ray excitation phosphor particles represented by the formula Ln.sub.2 O.sub.2 S:Eu, (Sm) wherein Ln is at least one element selected from the group consisting of yttrium, gadolinium, lanthanum, lutetium and scandium, a calcium salt and a strontium salt in stoichiometric ratios wherein (1) the amount of calcium is (1-x) mols in respect of x mols of strontium, x being a number within the range of 0≦x≦0.75, and (2) the total amount of calcium and strontium is within the range of 1 to 50 weight % of said oxysulfide phosphor, and firing the resulting mixture at a temperature within the range of 1000° to 1500° C.
Claim 5
Dependent Claim
127 words
A process for preparing a red colored phosphor comprising steps of mixing europium and optionally, samarium activated oxysulfide red emitting under cathode ray excitation phosphor particles represented by the formula Ln.sub.2 O.sub.2 S:Eu, (Sm) wherein Ln is at least one element selected from the group consisting of yttrium, gadolinium, lanthanum, lutetium and scandium, a calcium salt and a strontium salt in stoichiometric ratios wherein (1) the amount of calcium is (1-x) mols in respect of x mols of strontium, x being a number within the range of 0≦x≦0.75, and (2) the total amount of calcium and strontium is within the range of 1 to 50 weight % of said oxysulfide phosphor, and firing the resulting mixture at a temperature within the range of 1000° to 1500° C.
Claim 6
Dependent Claim
18 words
A process as defined in claim 3 wherein said x is a number within the range of 0≦x≦0.5.
Claim 7
Dependent Claim
24 words
A process as defined in claim 3 wherein said total amount of calcium and strontium is within the range of 2 to 20 weight%.
Claim 8
Dependent Claim
20 words
A process as defined in claim 3 wherein said firing temperature is within the range of 1150° to 1400° C.
Claim 9
Dependent Claim
21 words
A process as defined in claim 3 wherein a firing period is within the range of 10 minutes to 5 hours.
Claim 10
Dependent Claim
35 words
A process as defined in claim 3 wherein the amount of europium of said oxysulfide phosphor is within the range of 10 -2 to 1.5×10 -1 grams per 1 gram of an oxysulfide hose material.
Claim 11
Dependent Claim
23 words
A process as defined in claim 8 wherein said amount of europium is within the range of 2×10 -2 to 7×10 -2 grams.
Claim 12
Dependent Claim
38 words
A process as defined in claim 8 wherein said oxysulfide phosphor is activated with both europium and samarium and the amount of said samarium is less than 2×10 -3 grams per 1 gram of said oxysulfide host material.
Claim 13
Dependent Claim
23 words
A process as defined in claim 10 wherein said amount of samarium is within the range of 5×10 -4 to 1.5×10 -3 grams.
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) | 1984-04-27 | 1984-10-27 | 1985-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-27 | 1988-10-27 | 1989-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-27 | 1992-10-27 | 1993-04-28 | $7700.00 | Window Closed / Lapsed |