Evaluation of the electro-optic response of reflective liquid crystal cell

The electro-optic properties of the reflected light in a reflective mode, 4 5 degrees -twisted nematic liquid crystal (TNLC) cell were investigated in the voltage regions near and away from the Freedericksz transition threshol d. The measured reflectivity away from the threshold voltage (V-th) could n ot be described by the model which assumes a constant tilt angle as well as a linearized distribution of twist angle across the cell, although the dat a are well fitted near V-th.We found that in the voltage region away from V -th, the model considering the distributions of the tilt angle and the twis t angle should be applied for the calculation of the reflectivity. The dire ctor-axis distributions were obtained from the numerical integration of the Euler-Lagrange equation. (C) 2001 Elsevier Science B.V. All rights reserve d.