A Bistable Device of a Nematic LC Showing the Sign Reversal of the Dielectric Anisotropy

摘要

A bistability of nematic liquid crystals was devised on the pattern of checkerboard-like local rubbing; the alignment of the liquid crystal on neighboring domains was orthogonal each other. 4-fold symmetry of the pattern and liquid crystal frustration forced bulk director to orient along one of two average directions of the local rubbings. A liquid crystal orientation was switched to the other by in-plane electric field. To realize bi-directional switching it was needed to apply electric field along two different directions using two pairs of electrodes. In this experiment we used a liquid crystal, which changes the sign of dielectric anisotropy to frequency of electric field. It has a -merit of reducing number of electrodes into two, meaning simple electrodes structure. We successfully switched between two orientations with changing frequency of applying field.