| 摘要 |
PROBLEM TO BE SOLVED: To actualize the lightweight, compact back light unit with high luminance which can solve or eliminate conventional inconvenience and is greatly improved in luminance, visibility, etc., and the liquid crystal display device in which the back light unit is built. SOLUTION: The back light unit 1 includes a light guide plate 9 which can be arranged on the back face side of a liquid crystal display and a prism sheet 15 which can be arranged between the liquid crystal display and light guide plate 9. In this case, a prism lens sheet surface of the side facing the light guide plate 9 is formed to have a prism array 15a of prisms 15a formed into a saw-tooth shape and the light guide plate 9 has a front surface capable of facing the liquid crystal display and a back surface on the opposite side. The light guide plate front surface is made to have a plane nearly parallel to the liquid crystal display and the light guide plate back surface has a tilt surface 9B which slants by a specific angleαwith respect to the light guide plate front surface. |
