Retardation film and production method therefor, polarizing plate, and display device

Abstract

Provided is a producing method for a retardation film with a reverse wavelength dispersion property, which is highly reliable in terms of a small wavelength dispersion change and is low in display unevenness due to a position dependence of a retardation variation. The production method is designed for a retardation film which satisfies the following formulas (1) and (2):0.7<[450]/[550]<0.97  (1);and1.5×10<6.0×10  (2)(where: Re[450] and Re[550] represent, respectively, in-plane retardation values thereof as measured by using light of a wavelengths of 450 nm and light of a wavelength of 550 nm, at 23° C.; and Δn represents an in-plane birefringence thereof as measured by using light of a wavelength of 550 nm). This method comprises: a step of continuously conveying and supplying a long polymer film; a stretching step of stretching the polymer film in a direction transverse to a conveyance direction; a first shrinkage step of, after the stretching step, causing the polymer film to shrink in the transverse direction; and a second shrinkage step of, after the first shrinkage step, causing the polymer film to shrink in the transverse direction, wherein a shrinkage temperature T(° C.) in the first shrinkage step and a shrinkage temperature T(° C.) in the second shrinkage step satisfy the following formula (3):1<()≦10  (3).