Patent ID: 8550687

Claim:
A light guide plate shaped substantially like a plate, comprising: a light incident surface on which light is incident; a light exit surface, which is substantially orthogonal to the light incident surface, configured to allow the light to exit; and a reflective surface, which is substantially orthogonal to the light incident surface and opposite to the light exit surface, configured to reflect the light toward the light exit surface, wherein a plurality of optical units is arranged along the reflective surface in a direction orthogonal to the light incident surface; each of the optical units is shaped substantially like a quadratic prism convex toward the reflective surface and has a top surface and two slopes being opposite to each other with respect to the top surface; a dimension of the top surface is configured to be constant in a direction of arrangement of the optical units; and an interval between an adjacent optical units becomes greater as the adjacent optical units lie further away from the light incident surface in the direction of arrangement of the optical units.