Surface stabilized antiferroelectric liquid crystal (AFLC) devices with dissimilar alignment layers on the two surfaces are characterized by a shift in the electro-optical response [1] so that it is symmetric with respect to a nonzero voltage (figure 1). Because of this shift, the switching state of a pixel which is initially set by applying a short, selection, voltage pulse, may be maintained without applying any holding, bias, voltage. The stability at zero volts, together with the inherent range of grey levels, typical for antiferroelectric liquid crystals, has some potentially very interesting applications. Generally, the magnitude of the voltage shift changes slowly over time, depending on the driving conditions and the materials used. This varying asymmetry is an important obstacle for the implementation of this technology in real devices. Fig. 1. Asymmetric transmission–voltage characteristic of an AFLC cell with dissimilar alignment layers. 2. The influence of charge in asymmetric AFLC devices Charges in AFLCs can considerably influence the switching behavior of the device [2][3]. Measurements of the electric current flowing towards the electrodes of the device when a voltage step is applied can elucidate the nature and the behavior of these charges
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