Airbag tool polishing for aspherical glass lens molds

This paper presents a novel airbag tool polishing technique for small aspherical glass lens molds. For a mold material such as tungsten-carbide, an ultra-precise grinding technique is used to generate the aspherical surface. However, the residual tool marks of the spiral pattern and scratch unavoidably develop on the mold surface. Therefore, post-polishing is required to obtain the optical surface. Footprinting by the superposition method without trajectory control was applied to polish the finely ground aspherical lens mold. A white light interferometer confirmed the tool mark removal effect. The final surface toughness was Ra 2nm. Microscopic observation also showed a cleaner surface without scratches.