| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical film which exhibits a desired retardation value and hardly causes in-plane retardation value change with the lapse of time even when a film thickness is small, and to provide a composite polarizing plate using the optical film. <P>SOLUTION: The optical film includes a resin film containing a polypropylene based resin and an alicyclic saturated hydrocarbon resin, wherein an in-plane retardation value R<SB>0</SB>lies in the range of 40 to 500 nm, a retardation value R<SB>th</SB>in the thickness direction lies in the range of 20 to 500 nm, and when a refractive index in the in-plane lagging axis direction of the resin film is n<SB>x</SB>, a refractive index in the in-plane phase advance axis direction is n<SB>y</SB>and a refractive index in the thickness direction is n<SB>z</SB>, Nz coefficient defined by formula: Nz coefficient=(n<SB>x</SB>-n<SB>z</SB>)/(n<SB>x</SB>-n<SB>y</SB>) lies in the range of 0.9 to 3. There is also provided the composite polarizing plate including the optical film and the polarizing film. <P>COPYRIGHT: (C)2011,JPO&INPIT |
