Dual Domain Effects on a Homogeneously Aligned Nematic Liquid Crystal Cell Driven by a Fringe-Field

Abstract

The fringe-field switching (FFS) mode is known to exhibit both a wide viewing angle and high transmittance, owing to the approximated in-plane rotation of the liquid crystal (LC) director. However, in the bright state, the device shows bluish and yellowish color parallel and perpendicular to the LC director at off-normal directions since the LC director rotates only in one direction. The degree of color shift becomes even stronger when the retardation value of the cell is high. This problem was greatly improved using a wedge shape of only pixel electrodes. These wedged shaped pixel electrodes allow two different field directions to exist in a pixel, enabling the LC director to rotate in two opposite directions. Consequently, owing to the dual domain effect with unidirectional rubbing, the color shift dependence on the viewing angle is greatly reduced.