| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical film which can realize easy-to-see display with a high contrast ratio in a wide range, and can secure a stable phase difference value even under high temperature and high humidity conditions. <P>SOLUTION: In the optical film made by laminating a plurality of optical retardation films 2 on one side of a polarizing plate 1 made by laminating transparent protective films 1b on both sides of a polarizer 1a so that the absorption axis of the polarizing plate is at right angles or parallel to each lagging axis of the plurality of optical retardation films and also each lagging axis of the plurality of optical retardation films is parallel, a value of the refractive index of the optical retardation film; Nz =(nx<SB>1</SB>- nz<SB>1</SB>)/(nx<SB>1</SB>- ny<SB>1</SB>) satisfies 0.15 to 0.85 (where, nx<SB>1</SB>: the refractive index in the axial direction in which the in-plane refractive index is maximized, ny<SB>1</SB>; the refractive index in the direction perpendicular to the above axial direction, and nz<SB>1</SB>; the refractive index in the direction of film thickness), and a value of the in-plane phase difference Re<SB>1</SB>= (nx<SB>1</SB>- ny<SB>1</SB>) x d<SB>1</SB>satisfies 200 to 350 nm (where, d<SB>1</SB>[mm]: film thickness), and at least the transparent protective film 1b on one side contains a thermoplastic saturated norbornene resin. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
