| 摘要 |
PROBLEM TO BE SOLVED: To provide a light guide plate unit capable of attaining luminance enhancement in a front direction and provide a planar light source device, a transmission type image display device, and a light guide plate including this light guide plate unit.SOLUTION: A light guide plate unit 55 includes a side face 51c into which light enters, a rear face 51b which is a face crossing the side face 51c and on which a convex strip part 52 for reflecting light is arranged, and an emission face 51a which is a face on the opposite side to the rear face 51b and emits light. The convex strip part 52 includes a light guide plate 50 which extends in a length direction of the side face 51c and is arranged in a direction orthogonally crossing the extension direction, and a film group 40 including a microlens film 41, a prism film 43, and a diffusion film 45 which are arranged on an emission face 51a side of the light guide plate 50. Each of the plurality of the convex strip parts 52 has an external shape in which a peak angle &thetas;, or an angle having a largest emission intensity in an angular distribution of the light which is made incident from the side face 51c in the light guide plate 50 and is emitted from the emission face 51a, may become 20° or more and 67°or less. |
