Yuko Kizu

A Gradient Index Liquid Crystal Microlens Array for Light-Field Camera Applications

We have developed a microlens array (MLA) that utilizes liquid crystal (LC) for switching between light field and normal picturing modes in the camera application. The gradient index (GRIN) profile in an LC layer was obtained by applying the electric field distribution between a pair of molded-and-buried concave and planar electrodes. The concave array was formed by the imprinting method with ultraviolet curing resin. An indium tin oxide layer was deposited on the concave array to make the transparent electrode, which was then buried and flattened with the same resin. The transparency and flatness of the electrodes and resin keep the image quality high without applied voltage in the normal mode, and the electrode in the concave shape causes the LC layer to have a GRIN profile that acts as a MLA when voltage is applied in the light-field mode. The fabricated MLA showed suitable mode-switching operations by applying (for light-field mode) or not applying (for normal mode) a voltage of ±4 V.

Analysis of electro-optical properties of polymer-stabilized OCB and the application to TFT-LCDs

— A 9-in. full-color polymer-stabilized OCB TFT-LCD with stable bend alignment in the absence of an electric field was developed. The condition of the polymer stabilization, the characteristics of UV-curable monomers, and their influence on the configurations of the polymer network in the cell were studied. Possible models of the configuration were proposed and their relationship to the electro-optical properties was analyzed using a novel simulation method considering the distribution of anchoring effects from both alignment surfaces and the polymer network. It was suggested that a good performance such as high contrast ratio and fast response could be expected in the polymer network originating from newly developed monomers composed of multifunctional LC acrylates due to a relatively weak-anchoring effect and presumably its localization near the alignment surfaces. By using the newly developed monomers under the optimized polymer-stabilizing process, a high contrast ratio of 250:1 and fast response nearly equal to that of a conventional OCB cell were achieved.

5.1: Analysis of the Anisotropy of Bend Transition for OCB LCD with Low Initialization Voltage

To improve the efficiency of bend transition in OCB, its anisotropy was analyzed. The transition antiparallel (opposite) to the rubbing direction was significantly fast and this anisotropy remained at low temperatures. We propose two effects of LC shear flow on the anisotropy. Based on a pixel design that takes the anisotropy into consideration, 40% reduction of the initialization voltage in a 3-inch TFT-LCD has been achieved.