Numerical and experimental study on the optical performance of micro-pyramid functional surfaces

Abstract

Micro-pyramid functional surfaces are currently widely used in various advanced scientific, technological, industrial, and engineering fields with their excellent performances of compactness, light weight and higher heat transfer performance. Many recent studies have introduced micro cutting as a method to achieve high-quality micro pyramid surfaces. This paper concerns a micro-pyramid with a height and slope of 60 μm and 30°. Firstly, numerical simulation of the optical effect related to micro-pyramid surfaces was carried out to reveal the mechanism of functional surface imaging and its typical and potential applications. The simulated optical effect shows that the micro-pyramid can form four virtual images on the same side of an object. Next, a novel and simple fabrication method for micro-pyramidal structures was developed by using cross cutting with a 120° V-tip diamond tool by ultra-precision raster milling (UPRM), which can obtain good surface quality, high form accuracy and efficient productivity in contrast to grinding, laser machining and etching. Finally, precision injection molding was employed to replicate a micro-pyramid on the PMMA for optical testing. Although the quality of molded micro pyramid pattern decreased, optical testing showed that clear images were obtained, and the experimental results were consistent with the simulation results.