PRISM ARRAY

摘要

PROBLEM TO BE SOLVED: To improve the uniformity of luminance by forming a prism array irrelevantly to that the vertexes and base points of respective prisms are arrayed on a straight line. SOLUTION: Denoting the Y-directional position of a base point (Bn) of each prism (Qn) of the prism array (100) as Yn and the X-directional position as Xn, Yn is on a curved line (shown by the dashed line in the figure) of a nonlinear function Y=f(X). Then the X-directional intervals P of the base points of the prisms are constant and the angleαof the light-source side oblique surfaces of the prisms to the X axis and the angleβof the opposite light-source-side oblique surfaces to the X axis are constant. Consequently, the light-source side oblique surfaces (Sn) of the prisms become shorter and shorter in length with the distance from a light source and the opposite light-source side oblique surfaces (Rn) become longer and longer. Much light can be reflected toward a liquid crystal display device (30) even at a distance from the light source (20) to improve the luminance of a place distant from the light source (20).