P‐2.10: Design of a Freeform Surface Lens Based on the Optimization Target Illumination Distribution

Abstract

Illumination distribution on the target plane has a heavy effect on the design of a double freeform surface lens in a direct‐lit backlight unit. Gaussian distribution‐based design has better results than a uniform distribution. However, there exist two parameters in Gaussian distribution. This paper proposes a method to find the optimal values of μ and σ to obtain the better target plane irradiance distribution under an LED array. The simulated uniformity can be improved from 66.23% to 90.2% under the extended light source, which reduces the later optimization work and development time.