Illumination apparatus having light guide plate with curvedly tapered light coupling portion

摘要

An illumination apparatus includes a light source, and a light guide plate having an emitting surface and a light incident portion including a curved surface, and decreasing in thickness from the light source side towards the emitting surface. The curved surface has an S-shape as viewed from a side, with a convex portion on the light source side and a concave portion on the emitting surface with an inflection point in between, but closer to the emitting surface than to the source side.

主权项

1. A spread illuminating apparatus, comprising:
a light source; and a light guide plate having a light incident surface as an end face on which the light source is placed, and an emitting surface that is included in a surface connecting to one of two end sides in a longitudinal direction of the light incident surface and that emits light incident on the light incident surface, wherein the light guide plate has a light incident wedge portion integrally formed with the light guide plate, the light guide plate and the light incident wedge portion being both made of a transparent material, the light incident wedge portion includes a tilted surface, a thickness of the light incident wedge portion is reduced from the light incident surface side toward the emitting surface side, the tilted surface has an S-shape as viewed from a side, which has a convex portion on the light incident surface side and a concave portion on the emitting surface side with an inflection point therebetween, and a distance from the light incident surface to the inflection point is larger than the thickness of the light incident surface.