Patent ID: 7088508

Claim:
A dual-surface lens sheet having periodic gaps contained in lens sections on a front surface and a back surface in a lens sheet wherein pitch ratio of a unit lens on the front surface and the back surface is in a range of 1:2 to 1:30, and a shape of each unit lens is a triangle or a hexagon, wherein: the lens sections on the front surface and the back surface are micro-lens array sections in which the unit lenses are disposed in a matrix manner on a plain surface; one of the lens sections on the front surface and the back surface is a half-column-cylindrical-convex-lens group and the other lens section is a micro-lens array section in which the unit lenses are disposed utilizing an approximately secondary dimensional matrix; pitch in which the unit lens in the half-column-cylindrical-convex-lens group is disposed is 0.3 mm or less; pitch in which the unit lens in the micro-lens array section is disposed is 0.15 mm or less; a light emission angle emitted from each unit lens is more than ±30 degrees with respect to a normal of a main surface of the micro-lens array section; and a ratio of a transverse spherical aberration which is caused by each unit lens is designed to be in a range of 0% to 50% of a diameter of the unit lens.