| 摘要 |
PROBLEM TO BE SOLVED: To provide a back light unit and a liquid crystal display device including the back light unit, capable of being thinned, and outputting white light of excellent hue.SOLUTION: A back light unit includes a sheet-type wavelength converting member 16 including a surface emitting portion 10 emitting blue light Las excitation light, and a wavelength converting layer 15 receiving the blue light L, and emitting light of long wavelength side with respect to the blue light, and transmitting a part of the blue light, a retroreflective member group 20, and a reflection plate 18. A reflectivity R defined by a following formula, of the blue light in the retroreflective member group 20 is more than 70%. R=Ir(θe,φe,θr,φr)/Ie(θe,φe)×cosθe dθe dφe dθr dφr.SELECTED DRAWING: None |
