Precise Fabrication of Fresnel Flash Lens Featured with V-Grooved Microstructures

Abstract

Abstract A Fresnel lens is characterized by a micrometer-sized v-grooved structure, and its microstructure quality and curvature accuracy strongly influence its illuminance performance. In this study, a mold is designed for fabricating a Fresnel flash lens involving injection compression molding (ICM). The Taguchi method and parametric analysis are applied to examine the effect of process parameters (mold temperature, melt temperature, injection speed, packing pressure, compression pressure, and time) on the molding quality. Increasing the mold temperature and packing pressure generally improves the polymer melt fill in microsized cavities. ICM enables the realization of v-grooved microstructures with an accurate height replication rate (96.1%) as well as high curvature accuracy (6 μm), creating good optical qualities of the fabricated Fresnel lens with respect to maximum illuminance and illuminance uniformity.