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To date, devices exhibiting incidence-angle-dependent transmittance have been fabricated by imparting an angle to a bulk liquid crystal (LC) by aligning the LC in the vicinity of one substrate horizontally (with respect to the substrate) while aligning the LC in the vicinity of another substrate vertically. Another approach has been to control LC angles near substrates by blending or layering horizontal and vertical alignment films. In this study, we control LC angles near substrates by controlling the pretilt angles of blended alignment films; for specific angles, we use dichroic dyes to characterize the incidence angle dependence of these LC devices. Using a guest/host LC device with a pretilt angle near 45°, we successfully construct an LC element with a transmittance peak near a polar angle of 45°.

Zinc oxide (ZnO) films reportedly exhibit a rubbing effect for liquid crystal (LC) alignment. In this study, we investigated the LC alignment characteristics of solution-derived ZnO films according to the number of rubbing iterations. Uniform and homogeneous LC alignments were achieved on the rubbed ZnO films, regardless of the number of rubbing iterations. As the number of rubbing iterations increased, the surface energies of the rubbed ZnO films were similar to 42.20 mJ/m2, but the polar energy increased from 4.288 mJ/m2 to 6.470 mJ/m2. Additionally, the electro-optical characteristics of the twisted-nematic (TN) LC cells fabricated by rubbed ZnO films showed the best performance when the number of rubbing iterations was at five. By confirming that the ZnO film with improved physical, chemical, and electro-optical characteristics compared to the polyimide film achieved a perfect LC alignment through the conventional rubbing process, it indicates that the ZnO film can be an excellent substitute for the LC alignment film. In addition, it is expected that it can be applied to an LC-based virtual reality (VR)/augmented reality (AR) display system that requires a very fast response time through the excellent EO characteristics of the TN LC cell of the solution-derived ZnO film through the rubbing process.