Design and Modeling of Compact Tunable Lens Driven by Bilateral Dielectric Elastomer

Compared to traditional mechanical zoom lenses, tunable lenses driven by dielectric elastomers provide clear advantages in zoom range, response speed, and lightweight design. However, these lenses generally employ planar dielectroelastomer actuation, resulting in redundant structures. Additionally, the viscoelastic properties of dielectroelastomer materials often make precise control of focal length difficult. To overcome this issue, this paper introduces a compact, spherical dielectroelastomer-driven tunable lens with a radial size of 20 mm and an effective aperture of 8 mm. A dual-sided actuation structure allows for a 55% adjustment in focal length. Using thermodynamic principles and a spring–viscoelastic rheological model, static and dynamic models of the system have been developed. Experimental results demonstrate that the proposed model accurately predicts the lens’s dynamic response, with a root-mean-square error of less than 0.135, thereby providing a reliable theoretical basis for achieving high-precision focal length control.