| 摘要 |
PROBLEM TO BE SOLVED: To develop a light guide plate, with which a surface light source device having excellent use efficiency of light and superior luminance and its uniformity and a reflection or transmission type liquid crystal display device can be formed and also a front-light type device, having a converting system of colors of emitted light, can be formed. SOLUTION: This light guide plate consists of a plate body 1, having an upper face 1a, lower face 1b, and entrance side faces 1c, 1d consisting of two side facing opposite to each other between the upper and lower faces. The light guide plate has a light-exiting means (A) on one of the upper and lower faces, to allow the incident light from the entrance side faces to exit from the other face of the upper and lower faces. The light-exiting means consists of a repeated structure of recesses and projections, having ridge lines along the entrance side faces. The recesses and projections are composed of a pair of reflection planes for the propagating light which faces the respective entrance side faces and having the opposite inclination direction and of a pair of gentle slopes disposed between the reflection planes and having inclination directions opposite to the adjacent reflection planes. The surface light source device is produced by disposing a light source on each entrance side face of the light guide plate. The reflection or transmission type liquid crystal display device has a liquid crystal cell on the lower face or the upper face of the light guide plate in the surface light source device. |
