High fidelity fabrication of microlens arrays by nanoimprint using conformal mold duplication and low-pressure liquid material curing

The authors present a novel hyperfidelity fabrication method for microlens arrays. The method consists of the steps of (a) fabrication of a sacrificial master mold of a microlens array in a soft polymer by photolithography and thermal reflow, (b) conformal duplication of a daughter mold of complementary patterns in a hard material by dispensing an UV-curable material liquid on top of the polymer mold, planarizing the liquid with a flat quartz substrate, and curing the material, and (c) fabrication of microlens array using the hard daughter mold and nanoimprinting with an UV-curable lens material. This method has several advantages over conventional fabrication methods of microlens arrays including hyperfidelity, low cost, and high throughput.