| abstract |
The present invention aims at providing a chemically stabilized inorganic phosphor, among oxynitride phosphors including alkaline earths, which oxynitride phosphor emits orange or red light at longer wavelengths at higher luminance than conventional sialon phosphors activated by rare earths. The present invention further aims at providing a light emitting instrument based on the phosphor, for a lighting instrument excellent in color rendering property and for an image displaying apparatus excellent in durability. The solving means resides in provision of a fundamental phosphor comprising: nas a main component, an inorganic compound comprising: na composition on a pseudo-ternary phase diagram including AO (A is one kind or two or more kinds or element(s) selected from Mg, Ca, Sr, and Ba; and AO is oxide of A), Si 3 N 4 , and nSiO 2 as end members, respectively, and satisfying all of the following conditions: nin a composition formula, pAO-qSi 3 N 4 -rSiO 2 (p+q+r=1), 0.1 ¤ p ¤ 0.95 0.05 ¤ q ¤ 0.9 and 0 ¤ r ¤ 0.5 and nat least a metallic element M (M is one kind or two or more kinds of element(s) selected from Mn, Ce, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb) dissolved in a solid state, in the composition, wherein said composition is selected from an A 3 Si 3 O 3 N 4 crystal an A 3 Si 3 O 3 N 4 solid solution crystal, an A 3 Si 2 O 4 N 2 crystal, an A 3 Si 2 O 4 N 2 solid solution crystal, an A 3 Si 3-y O 3+y N 4-2y crystal (0 ¤ y ¤1.8) , and an A 3 Si 3-y O 3+y N 4-2y solid solution crystal (0 ¤ y ¤ 1.8). |