Patent ID: 9231150
Filing Date: 2016-01-05
CPC Classification: C09K,H01L,H05B

Claim Text:
1. A phosphor for a light emitting device which has an LED chip emitting ultraviolet to blue light, comprising: a phosphor particle composed of an europium and manganese-activated alkaline earth silicate phosphor emitting green to yellow light, the europium and manganese-activated alkaline earth silicate phosphor having a composition represented by a general formula: wherein x is a numeral (atomic ratio) satisfying 0.1≦x≦1.69, y is a numeral (atomic ratio) satisfying 0.01≦y≦0.05, z is a numeral (atomic ratio) satisfying 0.025≦z≦0.25, and u is a numeral (atomic ratio) satisfying 0.001≦u≦0.01; and a surface treatment agent of at least one selected from a silane coupling agent and an acrylic emulsion, the surface treatment agent being provided to cover a surface of the phosphor particle, wherein a luminance maintenance ratio is 98% or more, wherein the luminance maintenance ratio is represented by a formula: the luminance A is an initial luminance obtained by making the phosphor emit under a condition of a temperature of 23° C. and a humidity of 40%, and the luminance B is a luminance obtained by making the phosphor emit under a condition of a temperature of 23° C. and a humidity of 40% after leaving the phosphor under a condition of a temperature of 60° C. and a humidity of 90% for 12 hours.