| abstract |
An oxynitride phosphor activated by a rare earthnelement, represented by the formulanMe x Si 12-(m+n) Al (m+n) O n N 16-n :Re1 y Re2 x , wherein a part or all ofnmetal Me (where Me is at least one metal selected fromnthe group consisting of Ca, Mg, Y and lanthanide metalsnexcluding La and Ce) in α-sialon solid solution, isnsubstituted by lanthanide metal Re1 (where Re1 is atnleast one metal selected from the group consisting of Ce,nPr, Eu, Tb, Yb and Er), or two lanthanide metals Re1 andna coactivator Re2 (where Re2 is Dy), to be an emissionncenter. n A sialon type phosphor in the form of a powderncomprising at least 40 wt% of α-sialon represented bynthe formula (Ca x ,M y ) (Si,Al) 12 (O,N) 16 (where M is at leastnone metal selected from the group consisting of Eu, Tb,nYb and Er, 0.05<(x+y)<0.3, 0.02<x<0.27 and 0.03<y<0.3)nand having a structure such that Ca sites of Ca-α-sialonnare partially substituted by other metal M, at most 40nwt% of β-sialon, and at most 30 wt% of unreacted siliconnnitride. |