Patent ID: 6572236
Filing Date: 2003-06-03
Classification: G02B

Abstract:
A back light unit, comprising:a light guide plate for guiding light incident from an incoming surface thereof to an outgoing surface thereof to emit it as planar light; a reflection sheet located on a surface on the opposite side of said light guide plate to said outgoing surface; a diffusion sheet for diffusing said planar light from said outgoing surface of said light guide plate; and a prism sheet having a prism surface for partly returning the light emitted from said outgoing surface of said light guide plate, from said outgoing surface to an interior of said light guide plate for diffusion, wherein an edge portion between said incoming surface of said light guide plate and at least one of said outgoing surface and said opposite surface has a radius of curvature or a chamfer dimension of 140 &mgr;m or smaller extending continuously along substantially the entire length of said edge portion.