Patent ID: 7780331

Claim:
A surface illuminant equipment which includes a light guiding plate for guiding a source light from a light incidence plane which is set from at least one side surface from a pair of side surfaces opposing to each other; a prism sheet disposed opposing to a light emitting plane which is set from a front surface of the light guiding plate having a front surface and a back surface; and a reflection sheet disposed opposing to the back surface of the light guiding plate, comprising: a plurality of substantially parallel convex strip portions integrally formed with the light guiding plate on either one of the front surface and the back surface of the light guiding plate, fully extending in a direction from one side surface of the pair of side surfaces to the other and disposed in parallel in a direction orthogonal to the extending direction; and a plurality of concave portions formed on a side surface of each of the plurality of convex strip portions with an interval along the extending direction of the convex strip portion, wherein an inner wall of each concave portion is formed from at least two flat planes inclined with respect to three axial directions orthogonal to each other set from the extending direction of each of the plurality of convex strip portions, a width direction of the light guiding plate, and a direction orthogonal to both the extending direction and the width direction, respectively; and wherein in the case where two arbitrary convex strip portions adjacent mutually among the plurality of convex strip portions are set as a first convex strip portion and a second convex strip portion, respectively, the concave portion formed on the side surface of the first convex strip portion closer to the second convex strip portion and the concave portion formed on the side surface of the second convex strip portion closer to the first convex strip portion are axisymmetrical to a central axis between the first convex strip and the second convex strip when either one of the front surface and the back surface is viewed in the width direction of the light guiding plate.