Experimental research of amorphous twisted nematic liquid crystal displays

Amorphous twisted nematic liquid crystal display(a-TN) cells have been prepared without rubbing. The liquid crystal is injected into the cell in the isotropic phase and then cooled down to the nematic phase. The cooling rate and the uniformity are critical for the preparation of the a-THs. Nematic liquid crystals, bath with and without chiral dopant, have been used for the a-TNs. The electro-optical characteristics of the a-TN have been measured. Theoretical calculations have been carried out by 4 X 4 matrix method. A rising time of 700 mu s a and a decreasing time of 48ms have been detected. It is shown that the a-TN devices exhibit wide and uniform viewing angle characteristics. a viewing angle of +/- 30 degrees has been achieved.