Corona-Driven Electrostatic Self-Assembly of Tunable Liquid Lenses via Local Field Confinement.

The development of adaptive liquid lenses is often constrained by intricate electrode structures and limited actuation robustness. We propose a contactless electrostatic shaping strategy based on corona discharge and local electric field confinement. In this design, surface charges deposited on a PDMS droplet interact with a strongly nonuniform field from a microstructured channel, guiding the liquid to form a smooth, curvature-tunable lens. Experimental results show that the lens profile (contact angle and height) is voltage-tunable, achieving a maximum contact angle of 155.3°. The formation mechanism, primarily attributed to electrohydrodynamic circulation and localized field enhancement, contributes to high stability and reversibility. Furthermore, the lens can be asymmetrically deformed for real-time focal tracking, and its optical focal length is continuously adjustable. This work provides a robust and scalable strategy for the development of next-generation adaptive micro-optical systems.