Bioinspired Tunable Lens with Muscle‐Like Electroactive Elastomers

Abstract

Optical lenses with tunable focus are needed in several fields of application, such as consumer electronics, medical diagnostics and optical communications. To address this need, lenses made of smart materials able to respond to mechanical, magnetic, optical, thermal, chemical, electrical or electrochemical stimuli are intensively studied. Here, we report on an electrically tunable lens made of dielectric elastomers, an emerging class of “artificial muscle” materials for actuation. The optical device is inspired by the architecture of the crystalline lens and ciliary muscle of the human eye. It consists of a fluid‐filled elastomeric lens integrated with an annular elastomeric actuator working as an artificial muscle. Upon electrical activation, the artificial muscle deforms the lens, so that a relative variation of focal length comparable to that of the human lens is demonstrated. The device combined optical performance with compact size, low weight, fast and silent operation, shock tolerance, no overheating, low power consumption, and possibility of implementation with inexpensive off‐the‐shelf elastomers. Results show that combing bioinspired design with the unique properties of dielectric elastomers as artificial muscle transducers has the potential to open new perspectives on tunable optics.

Highly Stretchable and Transparent Ionogels as Nonvolatile Conductors for Dielectric Elastomer Transducers

“…[1][2][3] A soft machine uses the large deformation of soft materials to assist humans, 4, 5 operate robots, [6][7][8] monitor living tissues, 9,10 sense environment, 11,12 shape light, 13,14 and harvest energy. 15 A technology under intense development is electromechanical transduction using dielectric elastomers.…”

Two percolation thresholds and remarkably high dielectric permittivity in pristine carbon nanotube/elastomer composites

“…Dielectric elastomers (DEs), due to their large-strain actuation under the application of a high electric field or to convert mechanical energy into electricity, have found a wide range of applications, such as refreshable braille displays (Niu et al 2012;Yu et al 2009), tunable lenses (Carpi et al 2011), cell stretchers (Akbari and Shea 2012), soft robots (Pei et al 2003) and buoy generators (Chiba et al 2008). A high dielectric constant is desirable for the mentioned applications of DEs, but the existing DE materials (Keplinger et al 2012;Kofod et al 2003;Stoyanov et al 2013) have rather low dielectric constants.…”

Large, uni-directional actuation in dielectric elastomers achieved by fiber stiffening

“…Electroactive polymer (EAP) actuators have been widely studied as artificial muscles for diverse applications, including robotics, 1-3 motors, 4 adaptive optics, [5][6][7] Braille displays, 8 and bioengineering. [9][10][11] Within the family of EAP actuators, such as those made of polymer gels, 12 ionic polymer-metal composites, 13 conjugated polymers, 14 carbon nanotubes, 15 electrostrictive polymers 16 and liquid crystal elastomers, 17 dielectric elastomer actuators are considered particularly attractive because they resemble natural muscles, producing fast and large deformation in response to applied voltage.…”