Electro-optic characteristics of 90° twisted nematic liquid crystal display driven by fringe-electric field

Abstract

We investigated the electro-optic characteristics of a fringe-field driven twisted nematic (TN) display. In the absence of an electric field, the liquid crystals (LCs) are initially twisted 90° from the top to the bottom substrate under parallel polarizers so that the cell appears to be black. In the presence of a fringe-electric field, the LCs with negative dielectric anisotropy are rotated toward a plane that is almost perpendicular to the horizontal component of the fringe field, above the entire electrode surface. The cell then appears to be white, and shows high transmittance. In addition, the cell displays a wide viewing angle and has excellent color characteristics over a wide viewing range due to almost in-plane switching, unlike a conventional TN device where the LC director tilts upward in only one direction and results in a narrow viewing angle.

Characterization of Multi-Domain Bumps of Organic Resists in Color Filters for Wide-Viewing-Angle Liquid Crystal Displays

“…1) Other wide-viewing-angle techniques include in-plane switching (IPS) mode, fringe field alignment (FFA) mode, the twist nematic (TN) with optical-film compensation mode and optically compensated bend (OCB) mode. [2][3][4][5][6][7] For the compensated film TN mode, the performances of color difference and chromatic saturation are inferior to those of MVA mode, FFA mode, and IPS mode. MVA mode provides the merits of higher contrast ratio, wider viewing angle, faster switching time and no-rubbing surface treatment on alignment layer in cell process.…”