PRISM SHEET AND BACK LIGHT

摘要

PROBLEM TO BE SOLVED: To provide a lens sheet and a back light which can improve the optical efficiency when they are used for a liquid crystal panel and improve the brightness as a liquid crystal display device. SOLUTION: This back light is composed of a light source 1 and a planer light transmission body 2 having at least one incident plane facing to the light source and an outgoing plane. A prism sheet 6 having lots of prism rows arranged parallel to each other formed on at least one surface of a transparent substrate having a light-controlling function corresponding to aλ/8-7λ/8 phase plate is disposed on the outgoing plane of the light transmission body 2.