| 摘要 |
PROBLEM TO BE SOLVED: To provide a back light device of high luminance by forming a reflection plate of a light guiding body which efficiently reflects the light outgoing from the bottom of the light guiding body to the normal line direction of the light guiding body. SOLUTION: A tubular light source 1 and a reflection plate 5 of the light source are disposed on the side end of a transparent light transmission body 2. A surface light source means 3 which uniformly emits light all over the light transmission body 2 is formed on the bottom (opposite to the face where a liquid crystal display panel is to be disposed) of the light guiding body 2. The surface light source means 3 consists of, for example, a white diffusing and reflecting material in a dot state dispersed on the bottom of the light guiding body 2 with the dot density higher with the distance from the tubular light source 1. A reflection plate 4 to reflect the light outgoing from the light guiding body 2 is applied on the face of the light guiding body 2 in contact with the bottom of the body 2, and a diffusion plate 6 is applied on the top face of the light guiding body 2. The reflection plate 4 has a triangle shape in the direction parallel to the light-entering face of the body 2 and, a large numbers of vertical angles are uniformly arranged in the direction perpendicular to the light-entering face of the light guiding body 2. |
