LIGHT INTENSITY DISTRIBUTION CONVERSION ELEMENT, PLANAR LIGHT SOURCE DEVICE, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

A light intensity distribution conversion element (7) is provided with a light entry surface (7a), a light exit surface (7b), and total reflection surfaces (70a, 70b). The light entry surface (7a) allows entry of a light beam (6a) having directivity. The light exit surface (7b) has a curved surface portion (70c) for spreading the angular intensity distribution of the light beam (6a), the curved surface portion being concave-shaped with respect to the direction in which the light beam (6a) exits. The total reflection surfaces (70a, 70b) are near or adjacent to the curved surface portion (70c) and inclined with respect to the direction in which the light beam (6a) exits, and the light beam (6a) experiences total reflection at the total reflection surfaces. The light beam (6a), having experienced total reflection at the total reflection surfaces (70a, 70b), exits from the curved surface portion (70c).