| 摘要 |
PROBLEM TO BE SOLVED: To provide a back light for a liquid crystal display device capable of displaying bright images of a high contrast by maintaining the optical rotatory power of the polarization of the liquid crystal panel of the liquid crystal display device, such as liquid crystal television, and a liquid crystal display device. SOLUTION: This liquid crystal display device 2 is composed of a light source 3, a diffusion plate 4, the liquid crystal panel 6 having gratings 5 of a volume phase reflection type and polarizing plates 7, 8. When illumination light is made incident on the device from the diffusion plate 4 side, the gratings 5 reflects and diffracts the light of a predetermined angle range as reflected light 17 and makes only the transmitted light 16 of a narrow angle range on the liquid crystal panel 6 side. Consequently, the optimum optical rotatory power of the polarization is obtd. |
