| 摘要 |
PROBLEM TO BE SOLVED: To improve problems of a conventional light guide plate used for illumination of a liquid crystal panel and a scanner such that the conversion efficiency to convert the light from a light source into the illumination light is low and that the illumination light does not give sufficient luminance. SOLUTION: In the light guide plate 1 having an upper face 1a, a lower face 1b and a plurality of side faces (1c, 1d, 1e, 1f) to change the optical path of the light entering from a light source 2 to emit through the upper face, at least one side face of the side faces is formed into a prism form 16 (7, 8). Thus, the direction of the light emitting through the side face to the outside is changed to return inward of the light guide plate 1 so as to reuse the light as illumination light 5. Thus, the luminance of the illumination light is significantly improved compared with a conventional light guide plate. |
