Patent ID: 7851068

Claim:
An optical compensation film obtainable according to a melting method by use of a resin of an addition copolymer of a norbornene monomer and an olefin monomer, wherein, when a direction that gives the maximum in-plane refractive index is X axis, an in-plane direction perpendicular to X axis is Y axis, a film thickness direction is Z axis, refractive indexes at the wavelength of 590 nm in each axis direction are n X , n Y , and n Z respectively, and the film thickness is d, an in-plane retardation value defined as R=(n X −n Y )·d and a thickness direction retardation value defined as Rth=|(n X +n Y )/2−n Z |·d, both of which are measured under conditions at 23 degrees centigrade and a relative humidity of 50%, satisfy the inequalities of Rth/R≧5 and R≦9.5 (nm); and wherein a water absorption of said resin is not more than 0.1%.