Manufacture of Multiple-focus Micro Fresnel Lenses by Means of Nonrotational Diamond Grooving

The study deals with the manufacture of multiple-focus micro Fresnel lenses by means of nonrotational diamond cutting tools mounted on a 5-axis control ultraprecision machining center with the positioning accuracy of 1 nm and the rotational one of 0.00001 degree. Multiple-focus micro Fresnel lens, consisting of several micro Fresnel lenses, is not rotationally symmetric, thus requiring the introduction of 5-axis control ultraprecision machining center. Two-focus and three-focus micro Fresnel lenses are designed and manufactured by controlling the movement of nonrotational diamond cutting edge along the designed microgrooves at the cutting speed of 40 mm/min. As a result, the nonrotational diamond cutting method allows multiple-focus micro Fresnel lenses to be manufactured accurately and neatly without any burr generation.