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US3725704A
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US
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Rare earth phosphors for x-ray conversion screens
Assignee: Lockheed Martin Corp
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Filing: 1971-01-28
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Granted: 1973-04-03
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Expires: 1991-01-28
Abstract
Abstract This invention relates to phosphor screens for converting x-rays to visible or near visible radiation and phosphor materials used in such screens. More particularly, the x-ray conversion screens are of the type used, for example, in fluoroscopy, film intensifiers and x-ray image intensifier tubes and the phosphor materials are oxysulfides of lanthanum, gadolinium or lutetium activated with trivalent terbium.
Inventors
- 👤 R Buchanan
- 👤 M Tecotzky
- 👤 K Wickersheim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:00
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7767; C09K11/7769; C09K11/7771; G; G21; G21K; G21K4/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
56 words
A x-ray conversion screen in accordance with claim 1 wherein from about 0.01 percent to about 5 percent of saiD host metal ions of said phosphor have been replaced by trivalent terbium ions and said range of efficiencies is from a minimum efficiency of about 6 percent to an efficiency of at least about 18 percent.
Claim 2
Dependent Claim
56 words
A x-ray conversion screen in accordance with claim 1 wherein from about 0.03 percent to about 3 percent of said host metal ions of said phosphor have been replaced by trivalent terbium ions and said range of efficiencies is from a minimum efficiency of about 9.3 percent to an efficiency of at least about 18 percent.
Claim 3
Dependent Claim
16 words
A x-ray conversion screen in accordance with claim 1 wherein said screen is a fluoroscopic screen.
Claim 4
Dependent Claim
17 words
A x-ray conversion screen in accordance with claim 1 wherein said screen is a film intensifier screen.
Claim 5
Dependent Claim
19 words
A x-ray conversion screen in accordance with claim 1 wherein said screen is a image intensifier tube input screen.
Claim 6
Dependent Claim
70 words
In an image intensifier tube, a input screen consisting essentially of a phosphor, a binder for said phosphor and a substrate for said phosphor and said binder, said phosphor consisting essentially of at least one oxysulfide selected from the group consisting of lanthanum oxysulfide, gadolinium oxysulfide and lutetium oxysulfide in which from about 0.005 percent to 8 percent of the host metal ions have been replaced by trivalent terbium ions.
Claim 7
Dependent Claim
48 words
In a x-ray conversion screen, a phosphor consisting essentially of at least one oxysulfide selected from the group consisting of lanthanum oxysulfide, gadolinium oxysulfide and lutetium oxysulfide in which from about 0.005 percent to 8 percent of the host metal ions have been replaced by trivalent terbium ions.
References Cited (Backward Citations)
US3563909A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |