| 摘要 |
PROBLEM TO BE SOLVED: To provide a deflection structure plate which is applicable to light from a point light source, and suppresses luminance unevenness, and further to provide a surface light source device and a direct image display device.SOLUTION: The deflection structure plate 1 includes: first projection parts 10 which extend in a first direction and are arranged in parallel in a second direction on a first main surface 1a; and a second projection parts 20 which extend in a second direction and are arranged in parallel in the first direction on a second main surface 1b. A prism part which is the first projection part has flanks 13a, 13b and in the cross section of the prism part, each flank has an angle which is formed by the flank and normal directions of the two main surfaces 1a, 1b and becomes smaller on the hem side of the prism than the top end part side of the prism part. The vertex angle of the prism part is an angle with which at least a part of light incident on the top end of the prism part from the light source is totally reflected to an emission surface side in the prism part when the prism part is located on a center between two adjoining light sources. Further each second projection part 20 is constituted of a curved surface which intersects a plate thickness direction. |
