Alps Electric Co., Ltd.

Ohizumi Mitsuo

Tatsumaro Yamashita

Takuro Sugiura

One major surface of a light guide plate is formed, in stripe form in a plan view, with a plurality of prism grooves each consisting of a slight slope and a steep slope. The inclination angles of the slight slope and the steep slope are in ranges of 1&deg; to 10&deg; and 41&deg; to 45&deg;, respectively. The width of the steep slope in the one major surface of the light guide plate increases as the position increases from a light incident surface of the light guide plate such that a ratio of the width of the steep slope at a position farthest from the light incident surface to the width of the steep slope at a position closest to the light incident surface is 1.1 to 1.5.

Growing community of inventors

Fukushima-ken, Japan

Ohizumi Mitsuo