Patent ID: 7695167
Filing Date: 2010-04-13
Classification: G02B,G02F

Abstract:
1. An optical sheet comprising a plurality of lens elements provided successively in a row on one of principal faces of said optical sheet, wherein if a Z axis is taken in parallel to a normal line direction to said optical sheet and an X axis is taken in a direction of the row of said lens elements, a cross sectional shape in the XZ plane of each of said lens elements has a hyperboloidal or paraboloidal structure in which an entire surface of each of said lens elements satisfies the following expression: where R is the radius of curvature of a distal end vertex, K is a conic constant, and A, B, C are aspheric coefficients, and wherein the radius R of curvature, the conic constant K and the aspheric coefficients A, B, C satisfy the following numerical ranges: R≧0, K≦−1, 0<A<10