Experiments and modeling of conduction and charge accumulation in liquid crystal cells

A combination of different electrical measurement techniques is applied to liquid crystal (display) cells; voltage drop, current-voltage, dc stress measurements and impedance spectroscopy. It is found that at small timescale (seconds) conduction is dominated by transport of mobile ions, but at long timescale (hours) by (bulk) generation of extremely low mobility ions. These slow ions accumulate at ionic double layers at the liquid crystal-polyimid interface, giving rise to electric fields over the polyimid alignment layers. These processes of charge transport and accumulation are represented in consistent and insightful electrical network models.