Microlens array fabrication for light field imaging system

Abstract

We present a fabrication process that provides a method to obtain a high density polymer microlens array (MLA) with excellent geometric controllability. Microelectromechanical system(MEMS) fabrication processes on poly-silicon deposited quartz wafers, such as photo-lithography, dry etching and wet etching processes, can produce concave spheres on quartz master molds at large area and low cost. In addition, the radius of curvature (RoC) and sag height of the quartz mold is well controlled by adjusting the time to remove the quartz glass-like hard mask, thus providing a wide tuning range of RoC in MLA with low sag height. In the fabricated PDMS MLA, the lens exhibits a large curvature and the sag height of the convex shape is extremely low. In addition to MLA fabrication, we also produce hand-crafted light field cameras to demonstrate the applicability of our engineering MLA for lighting field imaging by integrating commercial digital cameras and assembled engineered MLA. Finally, we demonstrate a refocused image process that corresponds to the focus point adjustment of the one shot image through the post-image process.