β-TYPE SIALON PHOSPHOR POWDER AND LIGHT-EMITTING DEVICE

To obtain a β-type sialon phosphor having good emission intensity.SOLUTION: Provided is β-type sialon phosphor powder. In a fluorescence spectrum emitted when irradiating the phosphor powder with blue light having a wavelength of 455 nm, when a peak wavelength is denoted by λp [nm], a half band width of the peak is denoted by W [nm], absorption coefficients of the phosphor powder for light of wavelengths of 600 nm and 455 nm are denoted by A600 and A455, respectively, λp is 542 nm or less and a value of X, defined by X=(W×A600)/(A455-A600), is 10 nm or less.SELECTED DRAWING: Figure 1 【課題】発光強度が良好なβ型サイアロン蛍光体を得ること。【解決手段】β型サイアロン蛍光体粉末であって、この蛍光体粉末に、波長４５５ｎｍの青色光を照射したときに発せられる蛍光スペクトルにおいて、ピーク波長をλｐ［ｎｍ］し、ピークの半値幅をＷ［ｎｍ］とし、この蛍光体粉末の、波長６００ｎｍの光の吸収率をＡ６００とし、波長４５５ｎｍの光の吸収率をＡ４５５としたとき、λｐは５４２ｎｍ以下であり、Ｘ＝（Ｗ×Ａ６００）／（Ａ４５５－Ａ６００）で定義されるＸの値は１０ｎｍ以下である。【選択図】図１