Patent ID: 7360939

Claim:
A surface emitting device comprising: a light source; and a light-guiding plate having a side end surface for introducing light irradiated from the light source, a flat surface, and a light emission surface facing the flat surface, for propagating the incident light from the light source through an interior portion thereof, and emitting the light; wherein a plurality of minute prisms, each having a shape of a substantially quadrangular pyramid, are formed at the light emission surface by a plurality of first grooves and a plurality of second grooves that extend in a first direction and a second direction, and intersect each other at a predetermined angle, and the quadrangular prism having a first easy slope surface parallel with the first direction, a second steep slope surface parallel with the first direction, a third easy slope surface parallel with the second direction, and a fourth steep slope surface parallel with the second direction; and the first and third easy slope surfaces disposed at a light source side, and inclined at a predetermined angle with respect to the side end surface.