Patent ID: 9671547
Date: 2017-06-06
CPC Classifications: G02B

Claim:
1. An illumination device, comprising: a plurality of light sources arranged in one direction; and a light guide plate that has a side edge face as a light-receiving face facing the light sources and that guides light from the light sources received through the light-receiving face so as to emit illumination light from a light-emitting surface that is a front surface of the light guide plate, wherein a plurality of first concave prisms and a plurality of second concave prisms are formed so as to be recessed from the front surface or a rear surface of the light guide plate, the first concave prisms and the second concave prisms being arranged along a lengthwise direction of the light-receiving face, wherein the first concave prisms extend from the light-receiving face to a face of the light guide plate opposite to the light-receiving face, and the second concave prisms extend from the light-receiving face and are truncated in a prescribed area in a vicinity of the light-receiving face, the second concave prisms respectively being formed between adjacent said first concave prisms and recessed deeper than the first concave prisms, and wherein a base angle of each of the second concave prisms is greater than a base angle of each of the first concave prisms.