Method of Evaluating Tilt Domain in a Twisted Nematic Cell

The conditions for the formation of tilt domains in a twisted nematic cell have been studied in relation to the rubbing direction, the distribution of electric field at the electrode edges and the pretilt angle of liquid crystal molecules. The method of evaluating tilt domains in a twisted nematic cell using an electrode consisting of several segments with various angles to the rubbing directions was devised and some experiments were carried out. It is estimated that tilt domains are never induced when the pretilt angle is more than 1.2 degrees in a liquid crystal cell in the case where the angle between the upper surface rubbing direction and the lower surface rubbing direction, which is called the twisted angle, is 80 degrees.