Method of preparing cerium-activated yttriumaluminate phosphor of improved efficiency
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTetsuhiko Tomiki, Takeshi Takeda, Takeo Miyata, Fumio Muramatsu
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Abstract
A cerium-activated yttriumaluminate phosphor such as YA10.sub.3 :Ce featuring an enhanced luminous intensity is produced by adding a barium compound exemplified by BaO, BaCO.sub.3, Ba(OH).sub.2 and BaF.sub.3 to a mixture of source materials of the host material and the activator and baking the resulting mixture at a usual temperature ranging from 1000.degree. to 1400.degree. C. The barium compound preferably amounts to 0.001-8 mol% of the yttriumaluminate and may alternatively be introduced into a preliminarily baked and pulverized mixture of the source materials.
Claims7
A method of producing a phosphor comprising yttrium aluminate activated by cerium, the atomic ratio of yttrium to aluminum in the phosphor being substantially 1:1, the method comprising the steps of:
- a. preparing a mixture of Y.sub.2 O.sub.3, Al.sub.2 O.sub.3 and CeF.sub.3, the molar ratio of Y.sub.2 O.sub.3 to Al.sub.2 O.sub.3 being substantially 1:1, the quantity of CeF.sub.3 being such that cerium amounts to 0.1 to 5 mol % of said yttrium aluminate;
- b. adding a barium compound selected from the group consisting of BaO, BaCO.sub.3, BaF.sub.2, BaCl.sub.2 and barium salts which yield BaO at a temperature below 1400.degree. C. and selected from the group consisting of Ba(NO.sub.3).sub.2, Ba(OH).sub.2 and BaC.sub.2 O.sub.4, to said mixture in an amount of 0.001 to 20 mol % of said mixture;
- c. baking the resultant mixture at a temperature in the range from about 1000.degree. to about 1400.degree. C.;
- and
- d. washing the product of step (c) with nitric acid when said amount of said barium compound is larger than 8 mol %.
A method of producing a phosphor comprising yttrium aluminate activated by cerium, the atomic ratio of yttrium to aluminum in the phosphor being substantially 1:1, the method comprising the steps of:
- a. preparing a mixture of Y.sub.2O .sub.3, Al.sub.2 O.sub.3 and CeF.sub.3, the molar ratio of Y.sub.2 O.sub.3 to Al.sub.2 O.sub.3 being substantially 1:1, the quantity of CeF.sub.3 being such that cerium amounts to 0.1 to 5 mol % of said yttrium aluminate;
- b. adding a barium compound selected from the group consisting of BaO, BaCO.sub.3, BaF.sub.2, BaCl.sub.2 and barium salts which yield BaO at a temperature below 1400.degree. C. and selected from the group consisting of Ba(NO.sub.3).sub.2, Ba(OH).sub.2 and BaC.sub.2 O.sub.4, to said mixture in an amount of 0.001 to 8 mol % of said mixture;
- and
- c. baking the resultant mixture at a temperature in the range from about 1000.degree. to about 1400.degree. C.
Dependencies are inferred from the claim text.