CHARACTERIZATION OF BIAXIALLY-STRETCHED PLASTIC FILMS BY GENERALIZED ELLIPSOMETRY

An ellipsometric method for determining the optical constants and opti c axis orientations of a biaxially stretched plastic film is described . This technique works hy making angularly resolved generalized anisot ropic ellipsometric measurements in transmission and reflection and do es not require special or multiple sample azimuthal orientations. The measured data is then subjected to a. model regression procedure which can account for the propagation of multiple beams through biaxially a nisotropic layers. The results are consistent with Abbe refractometer measurements. The ellipsometric results near normal incidence also ind icate that the in-plane optic axes are twisted through the layer. (C) 1998 Elsevier Science S.A.