Patent ID: 8883309

Claim:
A method for producing a blue light-emitting silicate phosphor having the following composition formula (I): 3(Me 1-x ,Eu x )O. a MgO. b SiO 2 (I) wherein Me is Sr or a mixture of Sr and Ca, x is a number in the range of 0.001 to 0.110, a is a number in the range of 0.9 to 1.1, and b is a number in the range of 1.8 to 2.2, which comprises calcining a powdery mixture comprising a magnesium oxide powder, one of a combination of SrCO 3 and SrCl 2 and a combination of SrCO 3 , SrCl 3 and CaCO 3 , a EuO source powder and a SiO 2 source powder, said magnesium oxide powder having a purity of 99.9 wt. % or higher and a BET specific surface area in the range of 3 to 60 m 2 /g, in which the magnesium oxide powder has been prepared by bringing a metallic magnesium vapor into contact with oxygen whereby oxidizing the metallic magnesium vapor.