An automatic optical inspection system for measuring a microlens array with an optical interferometric microscope and genetic algorithm

Abstract

Purpose - The purpose of this paper is to propose an automatic optical inspection system for measuring the surface profile of a microlens array. Design/methodology/approach - The system set-up was constructed according to the principle of the Fizeau interferometer. After capturing the ring interference fringe images of the microlens with a camera, the diameter, profile information and optical properties were analyzed through a microlens surface profile algorithm using innovative image pre-processing with a precision of less than 0.09 micron. Findings - By integrating with the genetic algorithm, the XY-Table shortest moving path of the system is calculated to achieve the purpose of highspeed inspection and automatic microlens array surface profile measurement. Originality/value - The measurement results of this system were also compared with other systems, including the atomic force microscope and stylus profiler, to verify the measurement precision and accuracy of this system.