Planar texture improvement in cholesteric liquid crystal cells

We investigate the effect of thermal annealing (TA) on cholesteric cells. When a cell is heated to the cholesteric-isotropic transition temperature (T_ci), the cholesteric phase coexists with the isotropic phase. The isotropic domains become oily streaks, but the cholesteric domains merge with each other as the cell naturally cools to room temperature. A repeated T _ci TA processes that entails heating the cell to T_ci followed by cooling to room temperature effectively suppresses oily streaks and expands planar texture domains. Through this method, a defect-free cholesteric cell is achieved after five repeated T_ci TA processes.