| 摘要 |
PROBLEM TO BE SOLVED: To obtain a green-emitting phosphor which has improved luminance retention and color purity by specifying the compsn. of a green-emitting Tb- activated oxide phosphor to cause it to emit in a specified range of color tone. SOLUTION: This phosphor is a green-emitting Tb-activated oxide phosphor which is represented by the compsn. formula, contains 1×10<-5> -1×10<-2> g-atom/mol barium element, and emits light in a range defined by formulas: 0.325<=X<=0.360 and 0.540<=Y<=0.625 in the CIE chromaticity coordinates. In the compsn. formula, the following conditions are satisfied: 1×10<-2> <=x<=2×10<-1> , 1×10<-6> <=y<=2×10<-2> , 0<=z<=2×10<-1> , 1×10<-4> <=u<=5×10<-1> , and 0<=w<=1. The Tb concn. (x-value) of the phosphor is pref. in the range of 1×10<-2> to 2×10<-1> , still pref. 4×10<-2> to 1.4×10<-1> , since the emission chromaticity point (X, Y). i.e., the pref. green region, emits light with a high luminance in a range defined by the formulas: 0.325<X<0.360 and 0.540<=Y<=0.625.
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