| abstract |
An inorganic fluorescent substance, which emits orange or red light with longer wavelength than the conventional rare earth-activated sialon fluorescent substance, has a high level of brightness and is chemically stable, is provided. The inorganic fluorescent substance is represented by composition formula MaAbDcEdNeOfXg wherein M represents one or at least two activating elements selected from Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; A represents one or at least two divalent elements selected from Mg, Ca, Sr, and Ba; E represents one or at least two trivalent element selected from B, Al, Ga, and In; D represents one or at least two tetravalent elements selected from Si, Ge, and Sn; N represents nitrogen; O represents oxygen including the case where oxygen is not contained; X represents other element including the case where X is not contained; and a, b, c, d, e, f, and g are parameters which are regulated and set in specific respective regions, whereby the inorganic fluorescent substance has a high level of color rendering properties and emits orange light with a wavelength of not less than 570 nm and red light with a wavelength of not less than 600 nm. |