| US 7,572,391 B2 | ||
| Fluorescent substance and light-emitting device using the same | ||
| Naomi Shida, Tokyo (Japan); Masaaki Tamatani, Fujisawa (Japan); Yoshihito Tsutsui, Chigasaki (Japan); Kazuaki Ootsuka, Yokosuka (Japan); and Ryosuke Hiramatsu, Kawasaki (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan); and Toshiba Materials Co., Ltd, Kanagawa (Japan) | ||
| Filed on Jun. 19, 2008, as Appl. No. 12/142,078. | ||
| Application 12/142078 is a continuation of application No. 11/249946, filed on Oct. 13, 2005. | ||
| Claims priority of application No. 2004-303509 (JP), filed on Oct. 18, 2004. | ||
| Prior Publication US 2008/0251765 A1, Oct. 16, 2008 | ||
| Int. Cl. C09K 11/59 (2006.01); C09K 11/55 (2006.01) | ||
| U.S. Cl. 252—301.4F [428/403; 427/215] | 20 Claims |
| 1. A method for manufacturing a fluorescent substance comprising:
mixing a raw material for Eu, a raw material for Si, at least one raw material powder of alkaline earth, and at least one
selected from the group consisting of raw materials for La, Gd, Cs, and K to obtain a mixture of raw materials;
pre-firing the mixture for 1 to 3 hours in an air atmosphere at a temperature ranging from 500 to 700° C. to obtain a baked
material;
mixing the baked material and firing for 3 to 7 hours in a reducing atmosphere consisting of a mixed gas of N2/H2 at a temperature ranging from 1000 to 1600° C. to obtain a first fired product;
pulverizing the first fired product to obtain a pulverized first fired product;
placing the pulverized first fired product into a vessel;
placing the vessel housing the pulverized first fired product in a furnace;
purging the furnace with nitrogen gas in vacuum;
firing the pulverized first fired product for 2 to 6 hours in a reducing atmosphere consisting of N2/H2 and having a hydrogen concentration of 5% to 100% at a temperature ranging from 1000 to 1600° C. to obtain a fluorescent substance
consisting of an alkaline earth ortho-silicate.
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