Supertwisted Nematic Research Articles

A Monochromatic Black and White Supertwisted Nematic Liquid Crystal Display with a Single Cell and a Birefringent Film

To achieve a monochromatic black-and-white (B/W) STN-LCD with a single cell and a birefringent plastic film, the optimum conditions of optical properties in the birefringent film are analyzed theoretically and experimentally. By optimizing the film retardation to minimize the transmission of a STN-LCD at 550 nm, optical retardation in a STN cell is canceled and a B/W STN-LCD is obtained. By selecting the suitable conditions for compensating retardation of the STN cell, a B/W STN-LCD is achieved with the contrast ratio of 10:1.

Achromatized Super Twisted Nematic LCD Using Polymer Retardation Film

Abstract A new optical compensation method using retardation film has become possible to display black-and-white graphics in Super Twisted Nematic (STN) LCD.

Comparison of Temporal Changes of Molecular Alignments in a Twisted Nematic with a Supertwisted Nematic Liquid Crystal

The lagging effect of LC molecular alignments was studied through conoscopic figures in both a twisted nematic liquid crystal (TN LC) and a supertwisted nematic (STN) LC. The time required for the effect to show in STN LC was shorter than the time in TN LC. The time difference depended on film structure and the applied voltage, but it did not depend on the duration after the voltage was applied. It was qualitatively expressed by an equation of alternating current circuit considering the inductance which represents the inertial force. It became clear that the energy required for a tilt angle of 90 degrees could be reduced by using a double-block-pulse method instead of the method of a continuously applied electric field.

Invited Lecture. Matrix liquid-crystal display device technologies

Abstract Our recent studies of ferroelectric chiral smectic and super-twisted nematic (ST) multiplexed-matrix liquid-crystal displays (LCDs) and a thin-film-transistor (TFT) active-matrix twisted nematic (TN) LCD are presented, mainly in terms of liquid-crystal material and cell optimization. This is based on a consideration of their electro-optical characteristics. In addition the matrix LCD devices developed through these studies are introduced, including a 12-inch-diagonal video-rate multicolour ferroelectric LCD, a highly multiplexed genuine achromatic ST LCD with a single cell and a 4-inch-diagonal full-colour a-Si TFT-addressed TN LCD for a video display.