To provide a low-cost conversing sheet for the back light of a liquid crystal display having high conversing efficiency.

A conversing sheet in which plural equilateral triangles holding center-of-gravity points in common are arranged with their respective sides parallel and in which unit equilateral triangle Fresnel plates 41 which are constituted to reduce the variations of similar ratio relating to the innermost equilateral triangle in response to the distances of the center-of-gravity points are two-dimensionally and regularly arranged in the close-packed condition on a transparent base is transfer prepared by an ultraviolet curing method. Since spaces between adjacent sides of the equilateral triangles within the Fresnel plate 41 are designed to be reduced gradually in response to the distances from the center-of-gravity points, a light diffraction angle gets larger toward its outer circumferencial part to exhibit a conversing effect similar to a convex lens.