Lateral ion transport in nematic liquid-crystal devices

Abstract

Liquid crystals used in electronic displays usually contain small amounts of ions that move under the influence of the varying applied electric field. It is well known that the motion of ions perpendicular to the substrates may lead to modified electric fields resulting in image sticking effects. During operation, the modulation in the director tilt angle can also lead to a net residual lateral component of the ion motion, parallel with the glass plates. A sustained ac driving voltage will accumulate the lateral ion motion and may result in image sticking effects near the pixel edge. Such effects have indeed been observed in supertwisted nematic cells.

Ion Transport and Switching Currents in Smectic Liquid Crystal Devices

“…In some cases this anisotropy may lead to lateral transport of ions over a distance of mm [14][15][16]. The ion flux in the alignment layer is usually set to zero.…”

“…To close the system of equations, the dynamic behavior for the ions and the spontaneous polarization are needed. The ion fluxF ± in the liquid crystal [14] is described with a drift term containing the mobility tensorμ ± and a diffusion term containing the diffusion tensorD…”

Effects of the dispersion of zirconium dioxide nanoparticles on high performance electro-optic properties in liquid crystal devices

“…The EO characteristics enhanced by ZrO 2 nanoparticles can explain various mechanisms as follows. Impurity ions of NLCs are formed as a result of the purity of the NLC mixture and the fine debris possessing static electricity from the rubbing process, which may screen the PI surface and slightly affect both the threshold voltage and response time of the NLC cells [11]. The ZrO 2 nanoparticles dispersed in NLCs may play the role of trapping the impurity ions and capturing more ions as the doping concentration of the nanoparticles increases under applied voltage; thus the nanoparticles caused a lower threshold voltage and a faster response time.…”

Electro-Optical Properties of Liquid Crystals Composite with Zinc Oxide Nanoparticles

“…This might be explained by that while creating LC cells, static electricity might be generated, and then purity ions in LC mixed together; as a result of this process, impurity ions were created. Normally, impurity ions moderately aect the threshold voltage and response time of NLC cells [26,27], but zinc oxide NPs in NLC might capture impurity ions and aect the electro-optical properties signicantly. This is referred to eld screening effect (FSE).…”