Viewing angle controllable liquid crystal display with high transmittance

Abstract

All conventional viewing angle switchable liquid crystal displays with pixel division have drawback in light efficiency because the sub-pixel that controls viewing angle does not transmit the incident light at normal direction. In this paper, we propose new viewing angle controllable homogeneously aligned liquid crystal display in which the pixel is composed of red, green, blue, and white pixels. The colored pixels are driven by fringe-field switching and the white pixel is driven by complex field. In wide-viewing angle mode, the liquid crystal (LC) directors in all pixels rotate in plane, contributing to high transmittance. In narrow-viewing angle mode, the LC directors in color pixels rotate in plane for light transmission while the LC directors in white pixel can rotate or tilt upward by simultaneous fringe and vertical electric field. The high tilted LC directors generate light leakage in oblique directions which can be utilized for viewing angle control and also transmission at normal direction for image expression. The proposed device overcomes the long standing problem of transmittance sacrifice in the conventional devices.