Single-pass form-cutting for large-scale microlens array fabrication

Large-scale microlens arrays (MLAs) enhance detector performance by pixel-level light focusing, but achieving high-precision and high-efficiency fabrication of MLAs at the micron level remains highly challenging. This study introduces a novel single-pass form-cutting (SPFC) method that synchronizes linear-axis servo control and optimizes tool path design to achieve significant improvements in efficiency and precision for large-scale microlens array fabrication. The novelty of this approach lies in its ability to abandon the conventional rotational-axis (C-axis) motion of slow tool servo (STS) and instead employ purely linear-axis (X/Y/Z) synchronized servo control, completing each microlens unit with a single linear cut. This kinematic paradigm shift inherently reduces toolpath length by 91% and thereby machining time, while maintaining high surface quality and precision, outperforming traditional methods such as STS. The optimized tool path effectively mitigates the deformation at microlens unit adjacent shoulder. The machining accuracy of the SPFC method was verified by introducing volume errors. Through experiment, an MLA comprising 1024 × 768 units with a unit aperture size of 10 μm, and a sag height of 526 nm was fabricated within 53 hours, exhibiting a peak-to-valley (PV) value below 12 nm and a surface roughness (Sa) below 3 nm. These results confirm the high precision and efficiency of the SPFC method for large-scale MLA manufacturing.