Variable-focus lens with 30 mm optical aperture based on liquid–membrane–liquid structure

We report a liquid lens with a liquid–membrane–liquid structure in order to realize a variable-focus lens with a large optical aperture. We studied a typical liquid lens with a liquid–liquid structure and examined its physical limitation, namely, the capillary length, restricting the design of a larger-aperture liquid lens. We propose using elastic force instead of surface tension to acquire a much longer capillary length. We demonstrated that this approach can achieve sufficiently long capillary length when external pressure is loaded. A prototype lens with 30 mm aperture was constructed, and a resolution of 8.00 lp/mm was realized.