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US4822696A
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Process for the conversion of X-rays
Assignee: Agfa Gevaert NV
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Filing: 1987-08-05
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Granted: 1989-04-18
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Expires: 2007-08-05
Abstract
Abstract A process for the conversion of X-rays into blue and/or green light with a phosphor which on exposure to X-rays emits light the spectrum of which contains main intensity lines below 460 nm and/or main intensity lines between 530 and 570 nm, wherein said phosphor comprises a gadolinium gallium garnet compound having following empirical formula: Gd.sub.8-x-y Ln.sub.y Ga.sub.x O.sub.12 wherein: 5.14≧x≧4.90 and 0.45≧y≧0.001, and Ln is scandium (Sc) and/or one or more rare earth elements other than gadolinium. The invention is directed particularly to the use of said phosphor in an X-ray conversion screen applied in medical radiography.
Inventors
- 👤 Marinus J. Lammers
- 👤 George Blasse
- 👤 David R. Terrell
- 👤 Leo B. Alaerts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:40
CPC Classifications
G; G21; G21K; G21K4/00; C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7767; C09K11/7769; C09K11/7783; C09K11/7784; C09K11/7787
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
81 words
A process for the conversion of X-rays into blue and/or green light with a phosphor which on exposure to X-rays emits light the spectrum of which contains main intensity lines below 460 nm and/or main intensity lines between 530 and 570 nm, characterized in that said phosphor comprises a gadolinium gallium garnet compound having the following empirical formula: Gd.sub.8-x-y Ln.sub.y Ga.sub.x O.sub.12 wherein : 5.14≧x≧4.90 and 0.45≧y≧0.001, and Ln is scandium and/or one or more rare earth elements other than gadolinium.
Claim 2
Dependent Claim
81 words
A process for the conversion of X-rays into blue and/or green light with a phosphor which on exposure to X-rays emits light the spectrum of which contains main intensity lines below 460 nm and/or main intensity lines between 530 and 570 nm, characterized in that said phosphor comprises a gadolinium gallium garnet compound having the following empirical formula: Gd.sub.8-x-y Ln.sub.y Ga.sub.x O.sub.12 wherein : 5.14≧x≧4.90 and 0.45≧y≧0.001, and Ln is scandium and/or one or more rare earth elements other than gadolinium.
Claim 3
Dependent Claim
26 words
A process according to claim 1, characterized in that x is in the range 5.12≧x≧4.95 and Ln is at least 50 atom % of trivalent terbium.
Claim 4
Dependent Claim
25 words
A process according to claim 1, wherein Ln is Tb 3+ , y is in the range 0.45≧y≧0.09 and x is in the range 5.12≧x≧4.95.
Claim 5
Dependent Claim
67 words
An X-ray conversion screen consisting essentially of a phosphor dispersed in particulate form in a supported or self-supporting binder layer, wherein the binder is of organic nature, characterized in that said phosphor comprises a gadolinium gallium garnet compouond having the following empirical formula: Gd.sub.8-x-y Ln.sub.y Ga.sub.x O.sub.12 wherein : 5.14≧x≧4.90 and 0.45≧y≧0.001, and Ln is scandium (Sc) and/or one or more rare earth elements other than gadolinium.
Claim 6
Dependent Claim
67 words
An X-ray conversion screen consisting essentially of a phosphor dispersed in particulate form in a supported or self-supporting binder layer, wherein the binder is of organic nature, characterized in that said phosphor comprises a gadolinium gallium garnet compouond having the following empirical formula: Gd.sub.8-x-y Ln.sub.y Ga.sub.x O.sub.12 wherein : 5.14≧x≧4.90 and 0.45≧y≧0.001, and Ln is scandium (Sc) and/or one or more rare earth elements other than gadolinium.
Claim 7
Dependent Claim
27 words
An X-ray conversion screen according to claim 4, wherein Ln is Tb 3+ , y is in the range 0.45≧y≧0.09 and x is in the range 5.12≧x≧4.95.
Claim 8
Dependent Claim
21 words
An X-ray conversion screen according to claim 4, wherein the phosphor is in dispersed form in (a) film forming opganic polymer(s).
Claim 9
Dependent Claim
27 words
An X-ray conversion screen according to claim 4, wherein the phosphor in said layer is applied at a coverage in the range from 300 to 750 g/m2.
Claim 10
Dependent Claim
23 words
An X-ray conversion screen according to claim 4, wherein the phosphor has a particles size in the range of 0.1 to 20 μm.
References Cited (Backward Citations)
US3887807A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-17 | 1992-10-17 | 1993-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-17 | 1996-10-17 | 1997-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-17 | 2000-10-17 | 2001-04-18 | $7700.00 | Window Closed / Lapsed |