US3702828A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Europium-activated barium and strontium,calcium aluminum fluoride phosphors
Assignee: General Electric Co
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Filing: 1971-03-25
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Granted: 1972-11-14
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Expires: 1991-03-25
Abstract
Abstract EUROPIUM-ACTIVATED CALCIUM ALUMINUM FLUORIDE PHOSPHORS OF BARIUM AND STRONIUM ARE DESCRIBED WHICH HAVE BEEN FOUND TO BE EFFICIENT PRODUCERS OF SHARP LINE ULTRAVIOLET EMISSION RESULTING FROM 4F TO 4F ENERGY LEVEL TRANSTITIONS IN THE DIVALENT EUROPIUM, AS CONTRASTED TO PREVIOUSLY KNOWN LUMINESCENT MATERIALS UTILIZING DIVALENT EUROPIUM AS AN ACTIVATOR WHEREIN THE EMISSION IS DUE TO 5D TO 4F ENERGY LEVEL TRANSITIONS. SOLID-STATE AND PRECIPITATION METHODS OF PRODUCING THE NEW PHOSPHORS ARE DISCLOSED. THESE MATERIALS ARE USEFUL AS PHOSPHORS IN CATHODE-RAY TUBES, LAMPS AND OTHER APPLICATIONS.
Inventors
- 👤 Mary V Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:06
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7728; C09K11/7732; C09K11/7733
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-14 | 1976-05-15 | 1976-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-14 | 1980-05-15 | 1980-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-14 | 1984-05-15 | 1984-11-14 | $7700.00 | Window Closed / Lapsed |