Method of preparing cerium-activated yttrium silicate phosphor
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsYoji Fukuda, Fumio Fukushima, Yoshinobu Tsujimoto, Masakazu Fukai, Shinji Sugai
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Abstract
In the firing of a cerium-activated Y.sub.2 O.sub.3 -SiO.sub.2 system phosphor such as Y.sub.2 SiO.sub.5 :Ce and Y.sub.2 Si.sub.2 O.sub.7 :Ce, the improvement of adding BaF.sub.2 in a mol ratio of BaF.sub.2 /Y.sub.2 O.sub.3 of 0.01-0.1 is disclosed which increases the luminosity, emission intensity or both of the phosphor. Phosphors having improved properties are conveniently prepared according to the disclosed process.
Claims3
A method of increasing the emission intensity of a Y.sub.2 SiO.sub.5 :Ce phosphor at around the 450nm wavelength comprising adding BaF.sub.2 to a mixture of Y.sub.2 O.sub.3, SiO.sub.2 and CeO.sub.2,
- wherein the BaF.sub.2 is added in an amount such that the BaF.sub.2 /Y.sub.2 O.sub.3 mol ratio is 0.01 to 0.2 inclusive and wherein the SiO.sub.2 /Y.sub.2 O.sub.3 mol ratio is 1.0 to 1.2 inclusive,
- and thereafter firing the BaF.sub.2 -containing mixture at a temperature of the order of 1200-1500.degree. C in air or a reducing atmosphere of an inert gas containing up to 5% hydrogen to produce a cerium-activated phosphate phosphor exhibiting increased luminosity and emission intensity.
Dependencies are inferred from the claim text.