On the optical thickness dependence of the electro-optical properties of an in-plane switching LC cell

The optical transmission of a liquid crystal cell with in-plane switching (IPS) mode is studied as function of the thickness for different rubbing angles and anchoring energy. It was found that the light transmission has a maximum at the value of similar to 0.66 for the ratio of the optical path difference (introduced by the undisturbed cell) to X and that this value does not depend on lambda, in the case of a very strong anchoring energy and of a rubbing angle of 13 degrees. These experimental results agree very well with simulations using a simplified model. Moreover, the simulations have shown that the thickness corresponding to such a maximum optical path difference depends non-monotonously on the anchoring strength for five values of the rubbing angles (in the range 0 to 40 degrees). For a given anchoring energy this thickness decreases with increasing rubbing angle.