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US4068129A
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Bismuth activated rare earth oxybromide phosphors and X-ray image converters utilizing said phosphors
Assignee: General Electric Co
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Filing: 1976-12-13
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Granted: 1978-01-10
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Expires: 1996-12-13
Abstract
Abstract Oxybromides of lanthanum and gadolinium activated with bismuth are found to be superior in their conversion efficiency of X-rays to visible light when compared with conventional X-ray phosphors. The incorporation of the ytterbium ion in these phosphor materials produces reduced afterglow when used in X-ray image converter devices such as X-ray image intensifier tubes, fluoroscopic screens, and radiographic screens.
Inventors
- 👤 Jacob G. Rabatin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 03:06
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7767; C09K11/7769; C09K11/777; C09K11/7701; G; G21; G21K; G21K4/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
51 words
An X-ray image converter comprising well-formed crystals of a phosphor material having the general formula of LnOBr:Bi 3+ wherein Ln is one or more of La and Gd, with Bi being present as an activator at a concentration level in the approximate range 0.0005 - 0.15 mole per mole of phosphor.
Claim 2
Dependent Claim
51 words
An X-ray image converter comprising well-formed crystals of a phosphor material having the general formula of LnOBr:Bi 3+ wherein Ln is one or more of La and Gd, with Bi being present as an activator at a concentration level in the approximate range 0.0005 - 0.15 mole per mole of phosphor.
Claim 3
Dependent Claim
20 words
An X-ray image converter as in claim 1 wherein the phosphor material has chloride ion partially substituted for bromide ion.
Claim 4
Dependent Claim
39 words
An X-ray image converter as in claim 1 wherein the phosphor material further contains ytterbium ion at a concentration level from a small but effective amount sufficient to reduce afterglow up to approximately 0.01 mole per mole of phosphor.
Claim 5
Dependent Claim
21 words
An X-ray image converter as in claim 1 comprising a radiographic screen having the phosphor material supported on a base member.
Claim 6
Dependent Claim
18 words
A radiographic screen as in claim 4 adapted for intensifying the exposure of a photographic film to X-rays.
Claim 7
Dependent Claim
15 words
An X-ray image converter as in claim 4 wherein said phosphor is bismuth-activated lanthanum oxybromide.
Claim 8
Dependent Claim
56 words
A rare earth oxyhalide phosphor of reduced afterglow having the general formula: Ln.sub.1-x-y OBr:Bi.sub.x Yb.sub.y wherein Ln is one or more of La and Gd x is from 0.0005 to 0.15 mole per mole of LaOBr, and Y from a small but effective amount to reduce afterglow up to approximately 0.01 mole per mole of LaOBr.
Claim 9
Dependent Claim
56 words
A rare earth oxyhalide phosphor of reduced afterglow having the general formula: Ln.sub.1-x-y OBr:Bi.sub.x Yb.sub.y wherein Ln is one or more of La and Gd x is from 0.0005 to 0.15 mole per mole of LaOBr, and Y from a small but effective amount to reduce afterglow up to approximately 0.01 mole per mole of LaOBr.
References Cited (Backward Citations)
USRE28592E
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-09 | 1981-07-11 | 1982-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-09 | 1985-07-11 | 1986-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-09 | 1989-07-11 | 1990-01-10 | $7700.00 | Window Closed / Lapsed |