Research on Surface Quality Difference of Microlens Array Fabricated by Fast Tool Servo Cutting

Freeform surface optical components have gained increasing attention in recent years, and higher requirements have been put forward for economical and efficient fabrication techniques. Single point diamond turning with fast tool servo is the method to process nonrotational symmetric surface with high quality. However, the surface quality of different areas is not always the same in this way. In this paper, a microlens array is fabricated by fast tool servo cutting. The reason of surface difference is analyzed theoretically, and the Position-Velocity-Time interpolation method is used to improve the surface quality and reduce the difference between different regions. A microlens array consisting of 900 spherical lenslets was machined, the size of each spherical lenslet is 1.08 mm×0.5 mm. The form error of lenslet is about 1.5 um at the edge and 1 um at the center respectively, and the roughness value of Sa are 11 nm and 8.6 nm, the results show that the theory and simulation are correct, and the ability of fast tool servo technology to realize freeform processed with high precision is demonstrated.