LENS FILM, SURFACE LIGHT SOURCE DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a lens film which prevents a side lobe from being generated by refracting and making light incident from a normal direction to an inclined direction in a single lens on an adjacent convex lens in the lens film, to provide a surface light source device using the lens film and a liquid crystal display device. SOLUTION: The lens film 11 in which many unit convex lenses in a prismatic shape formed in a triangular shape in which a sectional apex angle α is 80 to 100 deg. are arranged on one surface of a light-transmissive base material so that their long shaft directions are parallel to each other is so formed that one unit convex lens part and an adjacent unit convex lens part are not provided successively with each other and the cross section crossing orthogonally in the long-shaft direction of the prism in a triangular shape leaves a flat part 114. This lens film can be formed similarly in semielliptic prisms in which a long to a short sectional radius is 1 to 3. Further, those lens films are usable for a surface light source device and a liquid crystal display device.