OPTICAL SHEET, MOLDING, PRODUCTION METHOD OF MOLDING AND PRODUCTION METHOD OF OPTICAL SHEET

摘要

An optical sheet having specified optical characteristics and being capable of being produced constantly and easily. The optical sheet (10) comprises a sheet-form base (15), and a plurality of unit prisms (20) arranged in an array on the base. The unit prism has a folded surface (21) including one bent portion (27), and a flat surface (22) joined with the folded surface. In a cross section extending along both of a normal direction to the base and the arranging direction of the unit prism, an isosceles triangle having a length from a vertex to a first base end portion equal to a length from the vertex to a second base end portion is defined by the first base end portion (26) consisting of the joint portion between the folded surface and the base, the second base end portion (28) consisting of the joint portion between the flat surface and the base, and the vertex (25) consisting of the joint portion between the folded surface and the flat surface. The bent portion is located outside the isosceles triangle.