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

摘要

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.