Grayscale Digital Light Processing 3D Printed Microlens for Scale-Down Self-Focusing Printing

In modern micro/nano fabrication, 3D printing technology drives industry transformation. However, existing technologies face bottlenecks in improving process efficiency and precision, while also struggling to achieve accurate fabrication of composite 3D microstructures. This study proposes a microlens self-focusing printing technique that integrates digital light processing (DLP) 3D printing with an optical microscope platform. By controlling image grayscale, microlenses with precise optical focusing capabilities are fabricated through millisecond-level single-exposure. Subsequently, without requiring additional hardware modifications, the self-focusing property of microlenses enables pattern printing with a feature size below 4 µm. Furthermore, the study demonstrates the technology's advantage in the integrated fabrication of composites by successfully printing of tetrahedral magnetic microrobots, which exhibit dynamic motion control under external magnetic fields. This fabrication strategy provides a simple and versatile new approach for high-precision microstructure fabrication.