| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high-luminance phosphor which hardly undergoes the decrease in emission luminance in the step of forming a phosphor film by coating the surface of phosphor particles with an Sr compound and/or a Ba compound. SOLUTION: The Sr compound and/or the Ba compound is preferably a borate or phosphate, and borate compounds including strontium tetraborate (SrB4O7) and barium tetraborate (BaB4O7) are especially preferable. The compound is applied preferably in such an amount that the total amount of Sr and Ba is 0. 005-5 wt.% of the phosphor, still preferably 0. 03-2 wt.%. The precipitate of the Sr compound and/or the Ba compound is formed in a slurry containing a phosphor suspended therein and is deposited on the surface of the phosphor to coat it. Thus, a phosphor having a high initial luminance is obtained and the decrease in emission luminance in the step of forming a phosphor film can be made small. When an aluminate phosphor, especially a blue-emitting phosphor (which is strongly required to be improved in decrease in luminance), is coated, the decrease in luminance during baking can be made small.
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