Patent ID: 8398893

Claim:
A method of preparing a halophosphate phosphor represented by Formula 1, the method comprising: mixing a metallic precursor compound, which comprises strontium pyrophosphate, strontium chloride and strontium carbonate, optionally a metal precursor compound selected from the group consisting of a barium precursor compound, a calcium precursor compound and mixture thereof, and an activator precursor compound to form a mixture; sintering the mixture under an oxygen or air atmosphere to form a sintered mixture; optionally mixing the sintered mixture with an aluminum precursor compound, a yttrium precursor compound, a lanthanum precursor compound and mixture thereof; milling the sintered mixture to form a milled product; and sintering the milled product under a reducing atmosphere: (Sr 5-(x+y) A x M′ y )(PO 4 ) 3 Cl.(M 2 O 3 ) z Formula 1 wherein A is barium or calcium, M′ is an activator and comprises at least one cation selected from the group consisting of Eu 2+ , Mn 2+ , Sb 2+ , Ce 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Yb 3+ and Bi 3+ , M is aluminum, yttrium or lanthanum, 0≦x≦4.8, 0<y≦0.2, and 0≦z<0.1.