US3829700A
Expired / Lapsed
US
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Rare earth phosphors for x-ray conversion screens
Assignee: WICKERSHEIM KG AUGUST
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Filing: 1972-11-24
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Granted: 1974-08-13
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Expires: 1992-11-24
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
2026-10-24 15:43
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: 8
Claim 1
Independent Claim
27 words
A method in accordance with claim 1 wherein from about 0.01 percent to 5 percent of the host metal ions have been replaced by trivalent terbium ions.
Claim 2
Dependent Claim
27 words
A method in accordance with claim 1 wherein from about 0.03 percent to 3 percent of the host metal ions have been replaced by trivalent terbium ions.
Claim 3
Dependent Claim
25 words
A method in accordance with claim 1 which comprises the further step of positioning a visible light detector in the path of said visible radiation.
Claim 4
Dependent Claim
47 words
A method in accordance with claim 4 wherein the step of positioning a detector comprises positioning a photosensitive film in the path of said visible radiation, whereby a record of an image carried by said x-ray energy is formed for later viewing in the visible energy spectrum.
Claim 5
Dependent Claim
43 words
A method in accordance with claim 4 wherein the step of positioning a detector comprises the step of intensifying the visible radiation by positioning a photocathode in the path thereof which emits photoelectrons that are accelerated and refocused on a cathode ray phosphor.
Claim 6
Dependent Claim
63 words
A method in accordance with claim 1 wherein the phosphor positioning step comprises positioning in said x-ray field a thin layer consisting essentially of at least one oxysulfide phosphor 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
31 words
A method in accordance with claim 1 wherein the phosphor positioning step comprises positioning in said x-ray field a phosphor consisting essentially of lanthanum oxysulfide to the exclusion of other phosphors.
Claim 8
Dependent Claim
31 words
A method in accordance with claim 1 wherein the phosphor positioning step comprises positioning in said x-ray field a phosphor consisting essentially of gadolinium oxysulfide to the exclusion of other phosphors.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |