A high-corrugation-rate self-Processing SiO2--ZrO2 hybrid sol-gel material for fabrication of microlens array

A novel high-corrugation-rate self-processing SiO₂--ZrO₂ hybrid sol-gel material has been developed and employed in single-step fabrication of refractive microlens array (MLA). In the proposed process, the SiO₂--ZrO₂ hybrid sol-gel film was exposed to ultraviolet through a binary mask and directly patterned into an MLA, which could be used as an end product with no further development or etching steps. Measurements showed that the surface relief depth could reach 1.32 μm, equivalent to 17.1% of the sol-gel film thickness. As expected, the fabricated refractive MLA had excellent surface smoothness, structural and dimensional conformity. The discrepancy between the designed and actual focal length of the MLA was 5.3%. The self-processing, being a true single-step method, was shown to be a practical, cost-effective, and promising fabrication technique for microoptical elements.