US3974389A
Expired / Lapsed
US
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Terbium-activated rare earth oxysulfide X-ray phosphors
Assignee: GTE Sylvania Inc
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Filing: 1974-11-20
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Granted: 1976-08-10
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Expires: 1994-11-20
Abstract
Abstract Terbium-activated rare-earth oxysulfide X-ray phosphors containing small amounts of cerium exhibit shorter decay times than the same materials without cerium. X-ray intensifying screens employing such phosphors enable improved resolution.
Inventors
- 👤 John L. Ferri
- 👤 James E. Mathers
- 👤 Ramon L. Yale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:49
CPC Classifications
G; G21; G21K; G21K4/00; C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7767; C09K11/7769; C09K11/7771; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
56 words
An x-ray phosphor consisting essentially of a host selected from the group consisting of lanthanum oxysulfide, gadolinium oxysulfide, and yttrium oxysulfide, from about 0.001 to about 0.1 moles of terbium per mole of host as an activator and, from an effective amount to 25 parts per million of said host of cerium, as a decay accelerator.
Claim 2
Dependent Claim
56 words
An x-ray phosphor consisting essentially of a host selected from the group consisting of lanthanum oxysulfide, gadolinium oxysulfide, and yttrium oxysulfide, from about 0.001 to about 0.1 moles of terbium per mole of host as an activator and, from an effective amount to 25 parts per million of said host of cerium, as a decay accelerator.
Claim 3
Dependent Claim
28 words
An x-ray phosphor according to claim 1 wherein said cerium is present in amounts of from about 1 part to about 10 parts per million of said host.
Claim 4
Dependent Claim
23 words
An x-ray phosphor according to claim 2 wherein said terbium content is from about 0.001 to about 0.006 moles per mole of host.
Claim 5
Dependent Claim
80 words
An x-ray conversion screen comprising an x-ray transparent, light translucent substrate and in an adherent relationship to at least one side of said substrate, an x-ray phosphor consisting essentially of a host selected from the group consisting of lanthanum oxysulfide, gadolinium oxysulfide, and yttrium oxysulfide, from about 0.0005 to about 0.1 moles of terbium per mole of host as an activator and, from an effective amount to 25 parts per million of said host of cerium, as a decay accelerator.
Claim 6
Dependent Claim
80 words
An x-ray conversion screen comprising an x-ray transparent, light translucent substrate and in an adherent relationship to at least one side of said substrate, an x-ray phosphor consisting essentially of a host selected from the group consisting of lanthanum oxysulfide, gadolinium oxysulfide, and yttrium oxysulfide, from about 0.0005 to about 0.1 moles of terbium per mole of host as an activator and, from an effective amount to 25 parts per million of said host of cerium, as a decay accelerator.
Claim 7
Dependent Claim
29 words
An x-ray conversion screen according to claim 4 wherein said phosphor contains cerium in amounts of from about 1 part to about 10 parts per million of said host.
Claim 8
Dependent Claim
28 words
An x-ray conversion screen according to claim 5 wherein said phosphor composition contains terbium in amounts of from about 0.001 to about 0.006 moles per mole of host.
Claim 9
Dependent Claim
22 words
An x-ray screen according to claim 6 wherein an organic light transparent binder is used to adhere the phosphors to said substrate.
Claim 10
Dependent Claim
25 words
An x-ray screen according to claim 7 wherein a protective light and x-ray transparent film is on the side phosphor and binder opposing the substrate.
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) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |