High-Performance PVC Gel for Adaptive Micro-Lenses with Variable Focal Length

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

doi:10.1038/s41598-017-02324-9

Abstract

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.

Highlights

We are interested in an electro-responsive, transparent, and non-ionic polyvinyl chloride (PVC) gel as one of smart polymer gels, which can lead to the considerable achievement of a novel adaptive focus-variable micro-lenses without bulky driving units and the problems associated with using liquids
We exploit these ideas and mimic the design of the crystalline lens and ciliary muscle of the human eye to introduce a bio-inspired adaptive PVC gel micro-lens with electrically tunable focus. 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
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

Summary

Introduction

We are interested in an electro-responsive, transparent, and non-ionic polyvinyl chloride (PVC) gel as one of smart polymer gels, which can lead to the considerable achievement of a novel adaptive focus-variable micro-lenses without bulky driving units and the problems associated with using liquids. The PVC gel showed poor elasticity or even crushing under a certain pressure due to the lower physical crosslinking network, formed by insufficiently entangled (anchored) polymer chains and few microcrystallites, resulting in deterioration of the focal length variation Several factors such as the molecular structure and concentration of the plasticizer in the PVC gel preparation strongly influence the mechanical, dielectric, and electrical properties of the PVC gels[14,15,16,17,18,19]. The proposed PVC gel showed high transmittance (T ≈ 92.6% at 550 nm), excellent ductility, and electroactive behavior Based on these properties, our adaptive focus-tunable PVC gel micro-lens had a large relative variation (about 500%) of the focal lengths under an electric field, comparable to that of the human lens. The electroactive micro-lens showed fast response speed (≤0.68 sec), silent operation, and low power consumption (12 mW)

Methods

Results

Conclusion