| 摘要 |
PROBLEM TO BE SOLVED: To provide a red phosphor suitable for electron beam-excited light emitting elements such as field emission displays (FEDs). SOLUTION: Provided is a europium-activated yttrium oxide which has a median diameter in the range of 2 to 8μm as measured by a laser diffraction/scattering method and a (δ2θ)cosθof 0.083 degree at the largest calculated from a diffraction peak from a 440 face measured by an X-ray diffraction method (whereinθrepresents a diffraction angle; andδ2θrepresents a half value width (degree) of a diffraction peak). The europium-activated yttrium oxide can be produced by mixing a europium-containing yttrium compound and a flux together in an aqueous system to prepare slurry, spray drying the slurry to obtain spherical secondary particles, and then firing the obtained secondary particles so that the median diameter after the firing becomes 0.65 to 0.75 time of the median diameter before the firing to bring the median diameter after the firing to 2-8μm. COPYRIGHT: (C)2008,JPO&INPIT
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