Patent ID: 8361347

Claim:
A blue phosphor comprising ZrO 2 and a metal aluminate that is represented by the general formula aBaO.bSrO.(1−a−b)EuO.cMgO.dAlO 3/2 .eWO 3 , where 0.70≦a≦0.95, 0≦b≦0.15, 0.95≦c≦1.15, 9.00≦d≦11.00, 0.001≦e≦0.200, and a+b≦0.97 are satisfied, the blue phosphor having a ZrO 2 content of 0.01 to 1.00% by weight, wherein two peaks whose tops are located in a range of diffraction angle 2θ=13.0 to 13.6 degrees are present in an X-ray diffraction pattern obtained by measurement on the blue phosphor using an X-ray with a wavelength of 0.774 Å.