| 摘要 |
PROBLEM TO BE SOLVED: To provide a light guide plate, surface light source device, and a transmission image display device capable of sufficiently dispersing light incident on an end surface, and reducing regions short of brightness.SOLUTION: It is assumed that a thickness direction of a light guide plate is a first direction, a longitudinal direction of an end surface is a second direction, and that a direction orthogonal to the first and second directions is a third direction. On the end surface, a plurality of convex portions extending in the first direction and arranged in parallel in the second direction are formed, and flat portions extending in the first direction are formed between the adjacent convex portions, respectively. If it is assumed that a distance between a tip end portion of the convex portion and the flat portion in the third direction is a height H, a distance between the adjacent convex portions is a flat portion length F, a distance between the adjacent flat portions is a width P, and an intersection angle between a tangential plane and the flat portion at the foot is assumed as a foot angle &thetas;, where the foot is the foot, which is intersection point between the convex portion and the flat portion, of the convex portion. The foot angle &thetas; and an aspect ratio (H/P), which is a ratio of the height H to the width P, of the light guide plate satisfy a predetermined relational expression. |
