Computer controlled polishing for middle or small double-sided aspheric lens

Taking a dual aspheric convex lens with a diameter of 62mm as example, CNC grinding and polishing technology was investigated. A standard procedure of processing was presented to fast and-efficiently polish small and medium double-sided aspheric lens. Based on the computercontrolled optical surface molding technology, two-step polishing was used, which included full aperture polishing and smalltool corrective polishing. Surface form error was fed back iteratively for compensation during polishing process, and the surface form gradually converged to the required accuracy. The experimental results show that the final accuracy on both sides of the surface is less than 0.5m and the center deviation is less than 0.01mm, which fulfils the accuracy requirement of aspheric element in optical system. The technique handles the center deviation of the dual aspheric surfaces and the accuracy of the center thickness properly while ensuring excellent surface form accuracy and good surface polish.