Biomimetic corneas of individual profile-followed coating for encapsulated droplet array

The ability to acquire a varifocal optical system with excellent reversibility and repeatability is crucial for many applications. However, current strategies for improving varifocal ability primarily focus on enlarging tunable focal length. The demonstration of an individually encapsulated microlens array is one of the key technological challenges in the varifocal microoptic industry. Inspired by corneas of natural eyes, we develop a self-assembly flow molding approach to fabricate a profile-followed coating onto the droplet surface for long-term encapsulation. Meanwhile, the coating has a supersmooth surface with roughness less than 1 nm within an area of 10 x 10 mu m(2), which unprecedentedly facilitates the high transparency and photosensitivity of a micro-optical system. Significantly, the elastic modulus of profile-followed coating is as low as 0.25 MPa, which satisfies the large varifocal capacity ranging from 773 to 1600 mu m at a low voltage of 5V. This work opens a new window for exploring the encapsulated fluid components with profile-followed coating in tunable optical systems.