The present invention aims at providing a chemically stabilized inorganic phosphor which emits orange light or red light at wavelengths longer than the conventional rare-earth activated sialon phosphor and which has a higher luminance.
The solving means resides in an inorganic phosphor design represented by a composition formula MaAbDcEdNeOfXg and containing: an M element (M is one kind or two or more kinds of element(s) selected from Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu); a divalent A element (A is one kind or two or more kinds of element(s) selected from Mg, Ca, Sr, and Ba); a trivalent E element (E is one kind or two or more kinds of element(s) selected from B, Al, Ga, and In); a tetravalent D element (D is one kind or two or more kinds of element(s) selected from Si, Ge, and Sn); nitrogen; oxygen (including an oxygen absent condition); and another X element (including an X absent condition); wherein the parameters a, b, c, d, e, f, and g included in the equation are adjusted to and set at particular regions to provide an inorganic phosphor which emits orange light at wavelengths of 570 nm or longer or red light at wavelengths of 600 nm or longer with excellent color rendering property.