US3575877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of calcium-containing alkaline earth metal halophosphate phosphors free of tricalcium phosphate
Assignee: Mallinckrodt Chemical Works
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Filing: 1968-06-12
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Granted: 1971-04-20
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Expires: 1988-06-12
Abstract
Abstract CALCIUM-CONTAINING ALKALINE EARTH METAL HALOPHOSPHATES PREPARED BY PRECIPITATION AT TEMPERATURES NOT EXCEEDING 56*C. ARE ESSENTIALLY FREE OF BETA-TRICALCIUM PHOSPHATE (TCP) AS A SECONDARY PHASE. THE PRESENCE OF TCP DISRUPTS THE NORMAL RELATIONSHIP BETWEEN MANGANESE CONTENT AND THE COLOR QUALITY OF THE LIGHT EMITTED BY A HALOPHOSPHATE PHOSPHOR CONTAINING MANGANESE AS A ACTIVATOR. PRESUMABLY, THIS IS DUE TO PREFERENTIAL ABSORPTION OF MANGANESE BY THE SECONDARY TCP PHASE.
Inventors
- 👤 Hugh C Bertsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:48
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/74; C09K11/75; C09K11/76; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/455
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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |