Bend Transition in Pi-cell

Abstract

Despite lack of knowledge on the nucleation process, the bend domain growth is observed as a motion of disclinations, whose velocity can be determined from the energy difference between two states by applying the boundary-layer model and a damping factor. The disclination velocity is proportional to the electric field across the cell. Upon application of a bias, a transient splay state having a fast bend spreading velocity emerges, which then changes into the asymmetric splay state very quickly, leaving the average bend spreading velocity very low. When the bias voltage drops down to zero, the asymmetric splay state relaxes back to a homogenous state, which, applying the bias voltage again, returns to the transient splay. The repetition of turning on and off the bias voltage enhances the average bend advancing velocity, and therefore is useful for fast bend transitions in an active-matrix liquid crystal display.