Bistable hybrid aligned nematic liquid crystal cells with topological rubbing patterns

Abstract

We introduce a topological rubbing pattern into hybrid aligned nematic liquid crystal (LC) cells to realize bistable LC orientation properties that can be switched only by applying voltage. The induced bistability is based on enhanced elastic frustration in the LC bulk layer of topologically rubbed LC cells. Specifically, we investigate the effect of the topological rubbing pattern with the topological charge of ±1 on the induced transition behavior from the stable ground state to the metastable excited state. The transition probability and time in the voltage application and removal processes are investigated to determine a better device structure suitable for bistable device applications. Finally, a stretched rhombic unit cell is introduced, and two- and one-step driving methods are applied to electrically realize a bistable switch function. Furthermore, the LC orientation model during the transition process is discussed.