Design and Evaluation of Wafer Level UV-Imprinted Aspherical Square Microlens Array to Increase Ray Convergence Efficiency of Image Sensor

Abstract

With the increasing demands of compact imaging module, the pixel size of image sensor has been decreased, and the design and fabrication of micro condensing elements have become a priority. A methodology for design and evaluation of wafer level UV-imprinted aspherical square microlens to increase ray conversance efficiency of image sensor was developed. A numerical method to model the surface of reflowed square microlens was proposed. To design the aspherical square microlens array, the effect of lens shape on the ray convergence efficiency was examined considering the misalignment, the residual layer thickness and the excessive chief ray angle. Finally, the designed square microlens array was integrated on a simulated image sensor substrate by a wafer level UV nano imprinting, and the ray convergence efficiency was measured and compared with the simulated results.