Patent ID: 7132065

Claim:
A process for making an optical film comprising: a) providing polymeric film comprising a crystallization modifier; a) stretching the polymeric film in a first direction; and b) stretching the polymeric film in a second direction different than the first direction forming a biaxially stretched polymeric film, wherein at least a portion of the stretching of the polymeric film in the second direction occurs simultaneous with the stretching of the polymeric film in the first direction; wherein the biaxially stretched polymeric film has a length and a width and being substantially non-absorbing and non-scattering for at least one polarization state of visible light; and having x, y, and z orthogonal indices of refraction wherein at least two of the orthogonal indices of refraction are not equal, an in-plane retardance being 100 nm or less and an out-of-plane retardance being 50 nm or greater.