| abstract |
A fluorescent substance includes a crystal of nitride or oxy-nitride having a β-type Si 3 N 4 crystal structure having Eu +2 solid-dissolved into it and emitting a fluorescent light having a peak within a range of 500 nm to 600 nm in wavelength by being irradiated with an excitation source. The fluorescent substance further includes another crystalline or amorphous compound different from the nitride or oxy-nitride crystal and a quantity of the nitride or oxy-nitride crystal contained in the fluorescent substance is 50 wt % or more. |