Patent ID: 8987986
Filing Date: 2015-03-24
Classification: C09K,H01L,H05B

Abstract:
1. A fluorescent substance which emits luminescence with a peak in the wavelength range of 500 to 600 nm under excitation by light with a peak in the wavelength range of 250 to 500 nm, which has an optical absorption coefficient α 560nm of 4×10 −5 or less at 560 nm, and which is represented by the following formula (1): in which M is a metal element selected from the group consisting of Ba, Sr, Ca, Mg, Li, Na and K; and x, y, z, u and w are variables satisfying the conditions of 0<x≦1, 0.8≦y≦1.1, 2≦z≦3.5, u≦1, 1.8≦z−u and 13≦u+w≦15, respectively.