Birefringent optical film, elliptically polarizing plate using the same, and liquid crystal display using the same

Abstract

The present invention provides a birefringent optical film having a high orientation for easily obtaining a desired retardation value and also a small photoelastic coefficient. The birefringent optical film includes at least two kinds of polymer materials. A total of products of Cn and Wn satisfies a numerical formula (1): Σ(Cn×Wn)≦20×10−8 cm2/N  (1) where Cn and Wn denote respectively a photoelastic coefficient and a volume fraction of each polymer material, and at least one of the polymer materials of the film has a photoelastic coefficient value of at least 60×10−8 cm2/N, while at least one of the remaining polymer materials has a negative value of photoelastic coefficient.

Dependencies are inferred from the claim text.