Patent ID: 6799859
Filing Date: 2004-10-05
Classification: G02B

Abstract:
A surface illuminant device having a plate-shaped light guide in which one principal surface serves as a light emission face and at least one end face serves as a light incident face, a light source disposed so as to extend along the light incident face of the light guide and a light travel direction converting prism sheet disposed on the light emission face of the light guide, characterized in that an incident surface of said prism sheet is disposed so as to face the light emission face of said light guide, plural elongated prisms are arranged in parallel to one another on the incident surface of said prism sheet so as to extend substantially in parallel to the light incident face of said light guide, said light guide has a light emitting structure with which light introduced into the light guide from said light source through the light incident face is emitted from the light emission face, and there is provided light focusing means for acting on light passed through said light guide and said light travel direction converting prism sheet so that the light is emitted from said prism sheet under a focused state, wherein the light emission face and/or the other principal surface of said light guide is curved in a convex or concave shape in a direction parallel or perpendicular to the light incident face of said light guide.