Flicker-Free Fringe-Field Switching Liquid Crystal Display Operable at Extremely Low Frequencies for Power Saving

Abstract

A fringe-field switching (FFS) liquid crystal (LC) mode used with a negative dielectric LC (n-LC) that is operable at an extremely low-frequency signal voltage regime, without image flickering, is proposed. By doping charge-trapping fullerenes (doping concentration: 0.2 wt%) into a low-resistivity polyimide LC alignment layer of the FFS n-LC mode, the mobile ionic-charge density within the n-LC layer can be drastically decreased. Thus, excellent voltage-holding ratios of 98.24% and 87.91% are achievable in the proposed FFS n-LC mode at low operation frequencies of 0.5 Hz and 0.2 Hz, respectively, corresponding to the improvement rates of 155.69% and 1127.05% at each operation frequency, compared with the FFS n-LC mode without the fullerene doping case. The evaluation results by the modulation flicker level reveal that the operation frequency of the proposed device scheme can be decreased significantly (approximate to 0.2 Hz) without inducing the perceptible image-flickering problems.