PRISM SHEET HAVING A CONCAVE PENTAGON STRUCTURE TO IMPROVE BRIGHTNESS AND SECURE A WIDE VIEWING ANGLE

摘要

PURPOSE: A prism sheet having a concave pentagon structure is provided to improve brightness and secure a wide viewing angle by increasing the surface that contributes to improvement in the brightness. CONSTITUTION: A plurality of prisms are consecutively arrayed in a prism array(24). A base layer supports the prism array at a lower part of the prism array. Each prism is comprised of a concave pentagon that forms bilateral symmetry on a basis of a vertical line which passes the vertex of the pentagon. An interior angle of the vertex of the concave pentagon is formed in a range of 30 degrees to 120 degrees. An exterior angle formed by a meet of an upper hypotenuse and a lower hypotenuse is less than 180 degrees. An interior angle made by a meet of the upper hypotenuse and the base of the concave pentagon is formed in a range of 5 degrees to 85 degrees. The base of the concave pentagon has length(w) in a range of 30 micrometers to 100 micrometers.