Single‐Step Inkjet Printing PDMS Microlens Arrays for Tunable‐Focus Artificial Compound Eyes

Abstract

Flexible, tunable‐focus artificial compound eyes (ACEs) have been extensively studied due to their large field of view (FOV), variable focal length, and large depth of field. The fabrication of flexible polydimethylsiloxane (PDMS) microlens arrays (MLAs) is a key issue for this system. Due to the difficulty of directly precision‐machining PDMS, PDMS MLAs typically need molds, which involve complex, costly, and hard‐to‐control methods like laser fabrication and lithography. In this paper, a moldless, single‐step inkjet printing method for PDMS MLAs is proposed. By optimizing the rheological properties of the PDMS ink and adjusting printing waveforms, voltages, and frequencies, this study achieves, for the first time, large‐scale inkjet printing fabrication of PDMS MLAs. The surface morphologies of the microlenses are uniformly consistent, resembling spherical caps. Subsequently, the optimized printed PDMS MLA film is bonded to a microfluidic chip to fabricate a hydraulically driven, variable‐focus ACE with the FOV tunable between 0° and 140° and the focal length tunable from 6 mm to infinity. The ACE is demonstrated to image the objects at various distances by altering the volume of the injected liquid and possessing good optical imaging quality.