Constructing a compact, simple, lightweight, and universal tuneable lens is challenging. Therefore, this paper suggests a miniature electro-focus/chromic tuneable lens whose focal point and optical transmittance are independently controlled by electric power. The proposed lens uses plasticized poly (vinyl chloride) and electrochromic gels to change its curvature and its brightness according to various electric powers. Due to this effect, we can observe not only the variation of the lens’s focal point but also the change of its transmittance. Moreover, as we removed the electric power, the shape of the proposed lens and its transmittance returned back to the initial condition. Through experimentation, the focal length of the proposed lens increased from 5 mm to 14.234 mm when the electric field input was increased, and the transmittance varied from 91.85% to 3.86% with increasing in electric current.

Existing soft actuators for adaptive microlenses suffer from high required input voltage, optical loss, liquid loss, and the need for assistant systems. In this study, we fabricate a polyvinyl-chloride-based gel using a new synergistic plasticization method to achieve simultaneously a high optical transparency and ultrasoft rubber-like elastic behavior with a large voltage-induced deformation under a weak electric field. By compressing the smooth gel between two sets of annular electrodes, a self-contained biconvex microlens is realized that is capable of considerable shape changes in the optical path. Each surface of the dual-curvature microlens can be independently adjusted to focus or scatter light to capture real or virtual images, yield variable focal lengths (+31.8 to −11.3 mm), and deform to various shapes to improve aberrations. In addition to simple fabrication, our microlens operates silently and consume low power (0.52 mW), making them superior to existing microlenses.

Dong-Soo Choi, Jaeu Jeong, Eun-Jae Shin and Sang-Youn Kim

We propose a focus-tunable double-convex (DCX) lens based on a non-ionic PVC (nPVC) gel to be used at close conjugates. The proposed lens is composed of an nPVC gel and two plates with electrodes. Each plate has a hole whose boundary and inner part are pasted with an electrode (anode) and has another ring shaped electrode (cathode) whose center point is the same as the hole’s center. The gel is sandwiched between an upper plate and a lower plate, and it is bulged inward between the holes of two plates by applied pressure from the plates (double-convex lens shape). The lens’s focal length changed from 3 mm to 24.5 mm with applied voltages from 0 V to 400 V. We also observed that the proposed lens’s field-of-view decreased from 121.9 ° to 41.9 ° according to the applied voltages. The proposed lens brings additional benefit for users with higher transmittance (over 94%).

Jin Woo Bae, Eun-Jae Shin, Jaeu Jeong, Dong-Soo Choi, Jong Eun Lee, Byeong Uk Nam, Liwei Lin, and Sang-Youn Kim

This paper presents a bio-inspired adaptive micro-lens with electrically tunable focus made of non- ionic high-molecular-weight polyvinyl chloride (PVC) gel. The optical device mimics the design of the crystalline lens and ciliary muscle of the human eye. It consists of a plano-convex PVC gel micro-lens on Indium Tin Oxide (ITO) glass, confined with an annular electrode operating as an artificial ciliary muscle. Upon electrical activation, the electroactive adhesive force of the PVC gel is exerted on the annular anode electrode, which reduces the sagittal height of the plano-convex PVC gel lens, resulting in focal length variation of the micro-lens. The focal length increases from 3.8 mm to 22.3 mm as the applied field is varied from 200 V/mm to 800 V/mm, comparable to that of the human lens. The device combines excellent optical characteristics with structural simplicity, fast response speed, silent operation, and low power consumption. The results show the PVC gel micro-lens is expected to open up new perspectives on practical tunable optics.