Patent US2907287A successfully refreshed from Google Patents.
US4024070A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a cerium activated luminescent rare-earth aluminate
Assignee: US Philips Corp
•
Filing: 1975-05-16
•
Granted: 1977-05-17
•
Expires: 1995-05-16
Abstract
Abstract A method of manufacturing a rare-earth aluminate, particularly a luminescent rare-earth aluminate, in which a starting mixture of the composite oxides or of compounds producing these oxides at an elevated temperature together with a flux is heated at a high temperature. At least one of the compounds rubidium fluoride, cesium fluoride and potassium fluoride is used as a flux.
Inventors
- 👤 Roelof Egbert Schuil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:13
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7774
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
136 words
In the method of manufacturing a luminescent rare earth aluminate selected from the group consisting of the cerium activated rare earth aluminates of the formula Ln 3 Al 5 O 12 and LnAlO 3 wherein Ln is at least one element selected from those having atomic numbers 57 to 71 inclusive and yttrium by heating a starting mixture of the oxides required to produce said aluminate or of compounds capable of producing such oxides upon being heated, together with a flux at a temperature of from about 1200° to 1400° C for about 0.5 to 4 hours the improvement wherein the flux is at least one compound selected from the group consisting of rubidium fluoride, cesium fluoride and potassium fluoride employed in a quantity of from 0.1 to 15% by weight based on the starting mixture.
Claim 2
Dependent Claim
136 words
In the method of manufacturing a luminescent rare earth aluminate selected from the group consisting of the cerium activated rare earth aluminates of the formula Ln 3 Al 5 O 12 and LnAlO 3 wherein Ln is at least one element selected from those having atomic numbers 57 to 71 inclusive and yttrium by heating a starting mixture of the oxides required to produce said aluminate or of compounds capable of producing such oxides upon being heated, together with a flux at a temperature of from about 1200° to 1400° C for about 0.5 to 4 hours the improvement wherein the flux is at least one compound selected from the group consisting of rubidium fluoride, cesium fluoride and potassium fluoride employed in a quantity of from 0.1 to 15% by weight based on the starting mixture.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the flux is employed in a quantity of from about 1% to 10% by weight.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein, after cooling, the resultant product is washed with water.
Claim 5
Dependent Claim
17 words
A method as claimed in claim 2, characterized in that rubidium fluoride is used as the flux.
Claim 6
Dependent Claim
21 words
A method as claimed in claim 2, characterized in that a luminescent yttrium aluminate having the garnet crystal structure is manufactured.
Claim 7
Dependent Claim
30 words
A method as claimed in claim 5, characterized in that the aluminate is defined by the formula Y 3 -x Ce x Al 5 O 12 , wherein 0.005 ≦x≦0.5.
References Cited (Backward Citations)
SU267784A1
Cited
SU236441A1
Cited
US3564322A
Cited
US3577350A
Cited
US3623994A
Cited
US3657140A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |