Patent ID: 8236201

Claim:
A blue phosphor represented by the general formula xSrO.yEuO.MgO.zSiO 2 where 2.970≦x≦3.500, 0.001≦y≦0.030, and 1.900≦z≦2.100 are satisfied, wherein a main peak is present in the range of diffraction angle 2θ=16.1 to 16.5 degree in the X-ray diffraction pattern obtained by measurement on the blue phosphor using an X-ray with a wavelength of 0.774 Å, and both of the following conditions (A1) and (A2) are satisfied: (A1) at least two peaks whose tops are located in the range of diffraction angle 2θ=15.3 to 16.1 degree are present; and (A2) at least two peaks whose tops are located in the range of diffraction angle 2θ=22.2 to 23.3 degree are present.