Fabrication of a focal length variable microlens array based on a nematic liquid crystal

Abstract

We fabricated a two-dimensional liquid crystal microlens array using a surface relief structure of ultraviolet (UV) curable polymer. The surface relief structure is produced by the spatially modulated UV exposure of the polymer through a photomask. Application of a voltage to the microlens changes the effective refractive index of the liquid crystal layer, which gives the change of a focal length. A variety of microlens structures and focal length variations could be produced on different surface relief structures by controlling the UV exposure.