Patent ID: 8460580

Claim:
A composition, comprising a phosphor that is a nitride or an oxynitride represented by the following formula: M 1′ a′ Sr b′ Ca c′ M 2′ d′ Al e′ Si f′ N g′ wherein: a′, b′, c′, d′, e′, f′ and g′ satisfy the following: 0.00001 ≦a′≦ 0.15; 0.1≦ b′≦ 0.99999; 0≦ c′< 1; 0≦ d′< 1; a′+b′+c′+d′= 1; 0.5 ≦e′≦ 1.5; 0.5 ≦f′≦ 1.5; and 0.8×(2/3+ e′+ 4/3× f′ )≦ g′≦ 1.2×(2/3+ e′+ 4/3× f′ ); M 1′ represents an activating element selected from the group consisting of Cr, Mn, Fe, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb; M 2′ represents Mg and/or Ba; an oxygen content of the phosphor is 5 wt % or less; the composition has an X-ray powder diffraction pattern measured in a 2θ range of from 10° to 60° using a CuKα line (1.54184 {acute over (Å)}) including Regions 1 to 6: Region 1 is a 2θ range of from 10° to 17°; Region 2 is a 2θ range of from 18.3° to 24°; Region 3 is a 2θ range of from 25.3° to 30.7°; Region 4 is a 2θ range of from 32° to 34.3°; Region 5 is a 2θ range of from 37° to less than 39.083°; and Region 6 is a 2θ range of from 41.5° to less than 46.973°; each peak of the X-ray powder diffraction pattern in Regions 1 to 6 has an intensity ratio I of 8% or less; and the intensity ratio I is defined by the formula (I p ×100)/I max (%), where I max represents a height of a most intense peak present in a 2θ range from 34° to 37° and I p represents a height of a measured peak, the intensity ratio being determined after background correction.