US3905912A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rare earth activated hafnium phosphate luminescent materials
Assignee: GTE Sylvania Inc
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Filing: 1974-09-25
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Granted: 1975-09-16
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Expires: 1994-09-25
Abstract
Abstract Luminescent materials having an Hf3(PO4)4 host with an activator selected from the group consisting of terbium, praseodymium, dysprosium, thulium and europium. Color emission varies from red through blue depending upon activator. Excitation radiation includes one or more of cathode rays (CR) long and short wavelength ultraviolet (U.V.) and x-ray. The phosphors are prepared by firing in open crucibles a homogeneous mixture of suitable compounds to yield the phosphor.
Inventors
- 👤 James E Mathers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:16
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7709
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
41 words
A PHOSPHOR MATERIAL HAVING THE GENERAL FORMULA HF3(PO4)4: RE WHEREIN RE IS SELECTED FROM THE GROUP CONSISTING OF: TERBIUM, PRASEODYMIUM, DYSPROSIUM, THIULIUM, AND EUROPIUM AND IS PRESENT IN AN AMOUNT OF FROM ABOUT 0.05 TO 0.1 MOLE PER MOLE OF HF3(PO4)4.
Claim 2
Dependent Claim
41 words
A PHOSPHOR MATERIAL HAVING THE GENERAL FORMULA HF3(PO4)4: RE WHEREIN RE IS SELECTED FROM THE GROUP CONSISTING OF: TERBIUM, PRASEODYMIUM, DYSPROSIUM, THIULIUM, AND EUROPIUM AND IS PRESENT IN AN AMOUNT OF FROM ABOUT 0.05 TO 0.1 MOLE PER MOLE OF HF3(PO4)4.
Claim 3
Independent Claim
93 words
The method of making a phosphor material having the general formula Hf3(PO4)4: RE wherein RE is selected from the group consisting of terbium, praseodymium, dysprosium, thulium and europium and is present in an amount of from about 0.05 to 0.10 mole per mole of Hf3(PO4)4 said method comprising the steps of: forming a substantially homogeneous mixture of a hafnium compound, a phosphate compound and a RE compound in amounts that will yield said phosphor upon subsequent heating; and heating said mixture in an open crucible for about four hours at about 1, 300*C.
Claim 4
Independent Claim
93 words
The method of making a phosphor material having the general formula Hf3(PO4)4: RE wherein RE is selected from the group consisting of terbium, praseodymium, dysprosium, thulium and europium and is present in an amount of from about 0.05 to 0.10 mole per mole of Hf3(PO4)4 said method comprising the steps of: forming a substantially homogeneous mixture of a hafnium compound, a phosphate compound and a RE compound in amounts that will yield said phosphor upon subsequent heating; and heating said mixture in an open crucible for about four hours at about 1, 300*C.
Claim 5
Dependent Claim
11 words
The method of claim 2 wherein said hafnium compound is HfO2.
Claim 6
Dependent Claim
12 words
The method of claim 3 wherein said phosphate compound is (NH4)2 HPO4.
Claim 7
Dependent Claim
12 words
The method of claim 4 wherein said RE compound is an oxide.
References Cited (Backward Citations)
US2427728A
Cited
US3488292A
Cited
US3527710A
Cited
US3600324A
Cited
US3586637A
Cited
US3609094A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |