Molecular Selective Pre-Tilt on Glass Surfaces and Color Difference between Two Twisted States in Surface Stabilized Ferroelectric Liquid Crystal Cells

Transmission spectra and chromaticities of surface stabilized states were numerically calculated by Berreman's 4×4 matrix method. It was found that molecular selective pre-tilt on both glass surfaces causes a color difference between two twisted states distinguished by the sense of C-director rotation. These colors alternate with each other when a cell is rotated by the apparent cone angle under crossed Nicols. This is consistent with the experimental observation. In relatively thin cells, the existence of the pre-tilt gives a contrast instead of a color difference.