Patent ID: 8349212

Claim:
A backlight of a liquid crystal display device having a white light emitting device, wherein the white light emitting device comprises: a light emitting diode having an emission peak in a range of 420 to 460 nm; and a mixture of a first phosphor having an emission peak in a range of 560 to 590 nm and a second phosphor having an emission peak in a range of 510 to 550 nm disposed above the light emitting diode, wherein the first phosphor comprises a Ca-α sialon phosphor having a composition expressed by the following formula: Ca x Si 12-(z+w) Al z+w O w N 16-w :Eu y 2+ , where 0.5<x<0.9, 0.01<y<0.15, 0<z<4, 0<w<4 and 0<z+w<4; the second phosphor comprises a SrSiON phosphor having a composition expressed by the following formula: SrSi 2 O 2 N 2 :Eu; and the white light emitting device emits white light in a region of x=0.27 to 0.33, y=0.25 to 0.35 in the 1931 CIE chromaticity coordinates by combination of the light emitting diode and the mixture of the first phosphor and the second phosphor, wherein the second phosphor further comprises Y 3 (Al,Ga) 5 O 12 :Ce.