US3980887A
Expired / Lapsed
US
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Silicon sensitized rare earth oxysulfide phosphors
Assignee: U S Radium Corp
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Filing: 1975-04-11
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Granted: 1976-09-14
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Expires: 1995-04-11
Abstract
Abstract Rare earth oxysulfide phosphors with excellent optical properties and optimum particle size control for use as photoluminescent, cathodoluminescent and X-ray luminescent phosphors are prepared by treating a solution of at least one salt of a rare earth metal and a salt of a rare earth activator to form solid salts and thereafter heating the oxidic compound with a sulfidizing agent and a silicon sensitizer, preferably in the presence of a fluoride. The rare earth oxysulfide phosphors thus obtained contain from 10 to 1,000 p.p.m. silicon sensitizer and, if used, 20 to 500 p.p.m. fluoride, incorporated in the crystal lattice structure.
Inventors
- 👤 James J. Mattis
- 👤 Melvin Tecotzky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:19
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7767; C09K11/7769; C09K11/7771
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
128 words
An X-ray intensifying screen comprising a substrate having coated on a surface thereof a plurality of particles of a rare earth oxysulfide phosphor consisting essentially of a rare earth oxysulfide matrix of the formula M 2-x O 2 S:xA wherein M is at least one rare earth element selected from the group consisting of lanthanum, gadolinium and yttrium, A is at least one rare earth activator selected from the group consisting of praseodymium, neodymium, samarium, europium, terbium, dysprosium, holmium, erbium, ytterbium, and thulium, and x is 0.001 to 0.1, silicon incorporated in said matrix in an amount from about 10 to 1,000 p.p.m. based on phosphor weight and, when M is gadolinium or yttrium, fluorine incorporated in said matrix in an amount from about 20 to 500 p.p.m.
Claim 2
Dependent Claim
128 words
An X-ray intensifying screen comprising a substrate having coated on a surface thereof a plurality of particles of a rare earth oxysulfide phosphor consisting essentially of a rare earth oxysulfide matrix of the formula M 2-x O 2 S:xA wherein M is at least one rare earth element selected from the group consisting of lanthanum, gadolinium and yttrium, A is at least one rare earth activator selected from the group consisting of praseodymium, neodymium, samarium, europium, terbium, dysprosium, holmium, erbium, ytterbium, and thulium, and x is 0.001 to 0.1, silicon incorporated in said matrix in an amount from about 10 to 1,000 p.p.m. based on phosphor weight and, when M is gadolinium or yttrium, fluorine incorporated in said matrix in an amount from about 20 to 500 p.p.m.
Claim 3
Dependent Claim
49 words
An X-ray intensifying screen according to claim 1 wherein the phosphor particles are crystalline compounds having the formula Y.sub.(2.sub.-x) Tb.sub.x O.sub.2 S wherein x is 0.001 to 0.1, modified by incorporation into the crystal lattice of 10 to 1,000 p.p.m. of silicon and 20 to 500 p.p.m. of fluorine.
Claim 4
Dependent Claim
49 words
An X-ray intensifying screen according to claim 1 wherein the phosphor particles are crystalline compounds having the formula Gd.sub.(2.sub.-x) Tb.sub.x O.sub.2 S wherein x is 0.001 to 0.1, modified by incorporation into the crystal lattice of 10 to 1,000 p.p.m. of silicon and 20 to 500 p.p.m. of fluorine.
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) | 1979-09-14 | 1980-03-15 | 1980-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-14 | 1984-03-15 | 1984-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-14 | 1988-03-15 | 1988-09-14 | $7700.00 | Window Closed / Lapsed |