Patent ID: 7820073

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, the second phosphor comprising at least one phosphor selected from the group consisting of phosphors having compositions expressed by the following formulae: —(Sr 1−x−y−z ,Ca x ,Ba y ,Mg z ) 2 SiO 4 :EU w 2+ where 0<x<1, 0.5<y<1, 0<z<1, 0.03<w<0.2 and 0<x+y+z+w<1; Y 3 (Al 1−x ,Ga x ) 5 O 12 : Ce, where 0<x≦1; and Eu-activated β-sialon; 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.