US3778615A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mixed alkaline earth sulfate phosphor fluorescent screens and radiographic elements
Assignee: Eastman Kodak Co
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Filing: 1971-05-18
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Granted: 1973-12-11
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Expires: 1991-05-18
Abstract
Abstract Novel phosphors comprising lanthanide-activated plural mixed alkaline earth sulfates such as europium-activated strontium barium sulfate, are prepared by coprecipitation of the lanthanide ion and said plural alkaline earth ions in dilute solution. The phosphors show high efficiency of fluorescence when excited by xrays and are particularly useful in intensifying screens in combination with radiographic image recording elements.
Inventors
- 👤 G Luckey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:57
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7713; G; G21; G21K; G21K4/00
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
22 words
The fluorescent screen of claim 1 in which barium comprises about 75 mole percent of the cation content of the phosphor composition.
Claim 2
Dependent Claim
71 words
A radiographic element comprising in integral or nonintegral combination a supported image-recording layer and a supported screen layer inclUding a mixed crystalline phosphor of europium-activated barium strontium sulfate wherein based on the cation content of the phosphor composition barium is present in a range from about 10 mole percent to about 90 mole percent and europium is present in a range from about 0.16 mole percent to about 1.4 mole percent.
Claim 3
Dependent Claim
22 words
The radiographic element of claim 3 in which barium comprises about 75 mole percent of the cation content of the phosphor composition.
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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |