| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing a retardation film having the relationship of n<SB>x</SB>>n<SB>z</SB>>n<SB>y</SB>, while easily regulating in-plane and thickness-direction retardation values. <P>SOLUTION: The production method includes: a sticking step of sticking a shrinkable film having a shrinkage ratio S<SP>160</SP>(MD) in the machine direction at 160°C of 10-50% and a shrinkage ratio S<SP>160</SP>(TD) in the transverse direction at 160°C of 0-20%, on one side or both sides of a stretched olefinic resin film to obtain a laminated film; and a heat shrinkage step of shrinking the laminated film by heating the laminated film so that the olefinic resin film satisfies the expressions: 100 nm≤(n<SB>x</SB>-n<SB>y</SB>)×d≤300 nm and 0.1≤(n<SB>x</SB>-n<SB>z</SB>)/(n<SB>x</SB>-n<SB>y</SB>)≤0.7, wherein n<SB>x</SB>, n<SB>y</SB>and n<SB>z</SB>represent refractive indexes in the in-plane slow-axis direction, in the in-plane fast-axis direction and in the thickness direction, respectively, and d represents the thickness, and so that the laminated film is shrunk in a shrinkage ratio in the machine direction of 0.5 to <0.8 time and in a shrinkage ratio in the transverse direction of 0.8-1.00 time. <P>COPYRIGHT: (C)2010,JPO&INPIT |
