Self‐Contained Focus‐Tunable Lenses Based on Transparent and Conductive Gels

Abstract Focus‐tunable lenses have found wide applications in optical communications, medical diagnostics, and consumer electronics. However, many focus‐tunable lenses have complex architecture, slow response, and low focal length variation, due principally to the separate design of optical path and activation mechanism and the use of liquid medium. Herein, a new self‐contained focus‐tunable lenses based on transparent and conductive gels are developed. The plano‐convex gels, acting both as lens and electrodes of actuator, with desirable curvature are precisely patterned by inkjet 3D printing. When a voltage is applied to the gel lenses, the elastomer membrane is stretched radially by Maxwell force, resulting in a reduction of lens thickness that corresponds to an increase of curvature radius. Therefore, a large focal length variation of 32–81% and a fast response speed of 80–153 ms are obtained. It is believed that this self‐contained focus‐tunable gel lenses can find many applications in portable optical devices, particularly suitable for space‐constrained tasks.