LUMINESCENT DEVICE

摘要

This invention provides a luminescent device comprising a blue fluorescent substance-containing fluorescent substance layer. The fluorescent substance layer comprises, as a blue fluorescent substance, an aluminate fluorescent substance comprising Ba, Sr, Eu, Mg, Al and O as constituent elements at an atomic ratio of Ba : Sr : Eu : Mg : Al : O = p : q : r : 1 : w : 17, wherein 0.70 = p = 0.95, 0 = q = 0.15, 0.05 = r = 0.20, p + q + r = 1, and 9.8 = w = 10.5. When the aluminate fluorescent substance is subjected to X-ray crystal structure analysis on the assumption that the aluminate fluorescent substance belongs to a space group P6₃/mmc, the aluminate fluorescent substance has a linear bond function s of not more than 1 as calculated by s = -11622 + 2043.07L_a + 199.24L₁ - 116.91L₂ wherein L_a represents a lattice constant, Å; L₁ represents atomic distance between Al(2) and O(5), Å; and L₂ represents atomic distance between Al(1) and O(4), Å.