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Takashi KUNIMOTO Alias DAUD Ikuo OZAKI Kazuaki OKAMOTO Koutoku OHMI Shosaku TANAKA Hiroshi KOBAYASHI
For vacuum-UV (VUV) phosphor application such as plasma display panels (PDPs) and mercury free lamps, CaAl2O4:Eu2+ (CA:Eu2+) showing 440 nm blue emission was examined. A single phase CA:Eu2+ was obtained by two step firing technique. The photoluminescence (PL) spectrum shows blue shift compared to that of blue-emitting BaMgAl10O17:Eu2+ (BAM:Eu2+) phosphors. CA:Eu2+ phosphors with β-tridymite crystal structure show less luminance degradation on baking in comparison to the commercial BAM:Eu2+ phosphors under VUV excitation. The initial PL intensity of CA:Eu2+ (Eu: 2 mol%) powder phosphor excited by 147 nm light was found to be about 60% of the commercial BAM:Eu2+ and the luminance of test panel with CA:Eu2+ (Eu: 1 mol%) was 37.4 cd/m2. The low test panel luminance with CA:Eu2+ phosphor is partly caused by the poor spread characteristics of the phosphor slurry due to the large particle size distribution. With improvement of luminance efficiency and the powder characteristics, there is a possibility that CA:Eu2+ phosphors can be applied for PDPs.