Manufacture of Aspherical Fresnel Lens with Ideal Cross-sectional Profile with Oxygen-free Copper and Acrylic Resin

Abstract

Fresnel lens is typically manufactured by means of photolithography and mechanical cutting by lathe. The study deals with a new machining method of lens grooves by use of a side-edge of diamond tool to enhance the cutting efficiency and to acquire the ideal cross-sectional profile of lens groove which consists of a perpendicular plane, a sharp bottom and a curved slope. The machining experiment was conducted to cut lens grooves with a pitch of 300 μm on an oxygen-free copper and an acrylic resin plate. The result showed an ideal lens groove with the surface roughness of 8 nm(P-V). The accurate focus of 100 mm was also confirmed by the optical assessment with a manufactured acrylic fresnel lens.