| abstract |
According to one embodiment, the luminescent material exhibits a luminescence peak in a wavelength ranging from 490 to 580 nm when excited with light having an emission peak in a wavelength ranging from 250 to 500 nm. The luminescent material has a diffraction peak intensity of the largest peak detected at 2θ=30.1-31.1° that is higher than the diffraction peak intensity of the peak detected at 2θ=25.0-26.0° in X-ray diffraction by the Bragg-Brendano method using Cu-Kα line and its composition is represented by (Sr 1−x Eu x ) 3−y Al 3+z Si 13−z O 2+u N 21−w (a part of the Sr may be substituted by at least one selected from Ba, Ca, Mg and Na, 0<x≦1, −0.1≦y≦0.3, −3≦z≦−0.52, and −1.5≦u≦−0.3, −3<u−w≦1). |