Ultraprecision forming of 2,500mm double-sided fresnel lenses applying hot hydraulic press technique

摘要

In this study, the authors proposed a new technique for fabricating double-sided fresnel lenses with 2500mm aperture, and developed a mold die for hot hydraulic press was developed for this purpose. We applied a forming technique using hot hydraulic press to fabricate the elements, and successfully obtained the required element with a sharp and smooth V-faced fresnel structure at both sides using spherical acrylic substrates.