US4006097A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Yb activated hafnium oxide phosphor and methods of making
Assignee: GTE Sylvania Inc
•
Filing: 1975-05-05
•
Granted: 1977-02-01
•
Expires: 1995-05-05
Abstract
Abstract A phosphor composition having the general formula HfO 2 :Yb with ytterbium being present in an amount of from 0.005 to 0.10 moles per mole of hafnium is disclosed. The phosphor can be prepared from the mixed oxides or from the oxalates, carbonates, or hydroxides by precipitating the latter from an aqueous solution. Firing takes place under a reducing atmosphere, preferably nitrogen, to reduce the ytterbium to the plus 2 ion. The phosphor is a bright green emitter under ultraviolet, x-radiation and cathode ray excitation.
Inventors
- 👤 Paul V. Kelsey, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:11
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7701
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
95 words
A method of making a phosphor composition having the general formula HfO 2 :Yb with Yb being present in an amount of from 0.005 to 0.10 moles per mole of hafnium which comprises the steps of: forming a substantially homogeneous mixture of appropriate amounts of the oxides of hafnium and ytterbium to yield the desired formulation; firing said mixture in a controlled atmosphere furnace under a nitrogen atmosphere for about 6 hours at about 1000° C; and mortaring said fired mixture and refiring in a nitrogen atmosphere at about 1250° C for about 6 hours.
Claim 2
Independent Claim
95 words
A method of making a phosphor composition having the general formula HfO 2 :Yb with Yb being present in an amount of from 0.005 to 0.10 moles per mole of hafnium which comprises the steps of: forming a substantially homogeneous mixture of appropriate amounts of the oxides of hafnium and ytterbium to yield the desired formulation; firing said mixture in a controlled atmosphere furnace under a nitrogen atmosphere for about 6 hours at about 1000° C; and mortaring said fired mixture and refiring in a nitrogen atmosphere at about 1250° C for about 6 hours.
Claim 3
Independent Claim
156 words
A method of making a phosphor composition having the general formula HfO 2 :Yb with Yb being present in an amount of from 0.005 to 0.10 moles per mole of hafnium which comprises the steps of: forming an aqueous solution of appropriate amounts of HfOCl 2 .8H 2 O and Yb 2 O 3 ; adding a sufficient amount of HNO 3 to said solution to solubilize said Yb 2 O 3 and heating and stirring constantly at a temperature of about 70° C until a clear solution is obtained; adding a precipitating agent selected from the group consisting of oxalic acid, ammonium carbonate, and ammonium hydroxide to form a precipitate; filtering and drying said precipitate; and first firing said precipitate in a controlled atmosphere furnace with a nitrogen atmosphere at about 980° C to 1000° C for about 2 hours and second firing said precipitate in said furnace at about 1200° C for 2 hours.
Claim 4
Independent Claim
156 words
A method of making a phosphor composition having the general formula HfO 2 :Yb with Yb being present in an amount of from 0.005 to 0.10 moles per mole of hafnium which comprises the steps of: forming an aqueous solution of appropriate amounts of HfOCl 2 .8H 2 O and Yb 2 O 3 ; adding a sufficient amount of HNO 3 to said solution to solubilize said Yb 2 O 3 and heating and stirring constantly at a temperature of about 70° C until a clear solution is obtained; adding a precipitating agent selected from the group consisting of oxalic acid, ammonium carbonate, and ammonium hydroxide to form a precipitate; filtering and drying said precipitate; and first firing said precipitate in a controlled atmosphere furnace with a nitrogen atmosphere at about 980° C to 1000° C for about 2 hours and second firing said precipitate in said furnace at about 1200° C for 2 hours.
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) | 1980-02-01 | 1980-08-02 | 1981-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-01 | 1984-08-02 | 1985-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-01 | 1988-08-02 | 1989-02-01 | $7700.00 | Window Closed / Lapsed |