Patent US3789014A successfully refreshed from Google Patents.
US3789014A
Expired / Lapsed
US
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Yttrium phosphate vanadate phosphor
Assignee: Philips North America LLC
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Filing: 1972-06-14
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Granted: 1974-01-29
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Expires: 1992-06-14
Abstract
Abstract A METHOD FOR IMPROVING THE RED LUMINESCENCE AND TOTAL LUMINESCENCE OF RARE-EARTH METAL ACTIVATED YTTRIUM PHOSPHATE VANADATE PHOSPHOR USING ACID MILLING. THE FIRED PHOSPHOR IS MILLING IN AN ACID SOLUTION. THE USE OF ACID DURING THE MILLING PROVIDES AN IMPROVED PHOSPHOR AS COMPARED TO A WATER MILLING FOLLOWED BY THE NORMAL WATER OR BASIC RISIN, AND EVEN PROVIDES AN IMPROVEMENT OVER WATER MILLING FOLLOWING BY AN ACID RESIN. PERFERABLY THE ACID USED IS EITHER CITRIC OR HYDROCHLORIC. THERE IS ALSO PROVIDED THE PHOSPHUR WITH THE IMPROVED SURFACE CHARACTERISTICS WHICH IS THE PRODUCT OF THIS PROCESS.
Inventors
- 👤 E Graff
- 👤 H Heytmeijer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:08
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7776; C09K11/7777
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |