Patent ID: 8491817

Claim:
A luminescent material which is featured in that it exhibits a light emission peak in a wavelength ranging from 580 to 700 nm when excited with light having a wavelength ranging from 250 to 500 nm and that it has a composition represented by the following general formula (1): (M 1-x R x ) a1 AlSi b1 O c1 N d1 (1) In the general formula (1), M comprises Sr; R comprises Eu; and x, a1, b1, c1 and d1 satisfy following relationships: 0<x≦1, 0.6<a1<0.95, 2<b1<3.9, 0.25<c1<0.45, 4<d1<5.7, wherein the luminescent material contains one component concurrently indicating diffraction peaks at diffraction angles (2θ) of 8.60-8.64°, 11.16-11.20° and 18.26-18.30° in the X-ray diffraction where CuKα characteristic X-rays have a wavelength of 1.54056 Å.