Toolpath generation for diamond shaping of aspheric lens array

Micro lens array is popular in opto-electrical applications, including back-light module of flat display devices and white-light LED illumination. The paper is to develop a toolpath generation software for precision shaping of micro aspheric lens array (ALA) with an ultra precision 4-axes free-form single point diamond turning (SPDT) machine (Toshiba ULG-100C(H3)) using a single-crystal diamond cutting tool. The diamond shaping toolpath generation of aspheric lens array (DSTG-ALA) with 3-D toolpath compensation of tool radius has been developed for m × n aspheric lens array. The NC program has been generated for direct-NC (DNC) to the CNC controller of the SPDT machine. A 1 × 6 micro ALA has been fabricated, and Form Talysurf surface profiler by Taylor Hobson Co. has been used to measure the finished lens array. The profile PRt = 0.3969 μm in X-axis, PRt = 0.4140 μm in Y-axis, and surface roughness Ra = 12.6 nm have been obtained. Therefore, the feasibility of developed DSTG-ALA program has been experimentally verified. Further application will focus on integrating the toolpath compensation with stylus tip reconstruction.