| 摘要 |
PURPOSE:To provide a back light panel having a high efficiency in converting to back light beams and uniform luminunce. CONSTITUTION:As for a light transmission body 1, a light incident surface is arranged on the left side, a light emitting surface 3 is arranged on the upper side and groove-shaped reflection parts 5 and 5' are formed on the rear surface 4 at a prescribed pitch. The groove depth of the front stage reflection part 5' is formed shallower than that of a rear stage reflection part 5. Among the inclined planes of respective reflection parts 5 and 5', at least the inclined planes close to the light incident surface are formed in a recessed shape when viewing from the inside of the light transmission body 1. Straight light G2 is taken out as G2', and light G3 made incident on the inclined plane near an apex P at a small tilt angle facing downward with respect to a horizontal plane is taken out as G3' while satisfying a total reflection condition. The straight light G1 made incident on the inclined plane while grazing the apex of the front stage reflection part 5' is totally reflected with enough space, and then, taken out as G1'. |
