OPTICAL SHEET AND DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To effectively reduce a value of birefringence and an in-plane variation of the birefringence of an optical sheet including a nano structure.SOLUTION: An optical sheet 10 has a nano structure 20 on at least one surface 10a thereof, the structure including unit elements 21 arranged at a pitch of less than 1 μm. The nano structure 20 is formed by using a thermoplastic resin. An average &Dgr;nof birefringence of the optical sheet and a standard deviation &sgr;of the birefringence of the optical sheet satisfy the following conditions (a):&Dgr;n≤50×10and (b):(&sgr;/&Dgr;n)≤0.10.