LENS FILM AND SURFACE LIGHT SOURCE DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent a lens film in a surface light source device for lighting up a liquid crystal panel from damaging other optical sheets. SOLUTION: In a lens film 10, which arranges plural unit lenses 12 on one surface of a transparent substrate sheet 14 at pitches of 30 to 70 μm in the one or two dimensional directions and comes into contact with the surface of another optical sheet at the vertexes of the unit lenses 12, the cross section of the vertex parts 12B of the unit lenses 12 in the lens film 10 are made in a circular arcuate shape of 10 to 25 μm in the radius. At least the tips of the unit lenses 12 are desirably made of a material with 70 to 90 Shore hardness.