Retardation film and production thereof.

摘要

A retardation film comprising a polymerized liquid crystal oligomer having positive intrinsic birefringence, also having a glass transition temperature of 50 DEG C or below and showing nematic or smectic phase, characterized in that the optical axis of the film lies in the film plane, that the value of retardation (product of anisotropy of refractive index DELTA n of said film and film thickness d) at 30 DEG C is 100 nm or above, and that the ratio of the value of retardation at 80 DEG C to that at 30 DEG C is 0.95-0.5, allows proper adjustment of the rate of change with temperature in accordance with the rate of change with temperature of the liquid crystal cell used in combination with the film, and can provide liquid crystal display devices showing excellent display performance at high temperatures.