Smart Lenses with Electrically Tuneable Astigmatism

Abstract

The holy grail of reconfigurable optics for microscopy, machine vision and other imaging technologies is a compact, in-line, low cost, refractive device that could dynamically tune optical aberrations within a range of about 2–5 wavelengths. This paper presents the first electrically reconfigurable, fully elastomeric, tuneable optical lenses with motor-less electrical controllability of astigmatism in the visible range. By applying different voltage combinations to thin dielectric elastomer actuator segments surrounding a soft silicone lens, we show that the latter can be electrically deformed either radially or along selectable directions, so as to tune defocus or astigmatism, up to about 3 wavelengths. By mounting the new lenses on a commercial camera, we demonstrate their functionality, showing how electrically reconfiguring their shape can be used to dynamically control directional blurring while taking images of different targets, so as to emphasize directional features having orthogonal spatial orientations. Results suggest that the possibility of electrically controlling aberrations inherent to these smart lenses holds promise to develop highly versatile new components for adaptive optics.

Electrically Tunable Lenses: A Review

“…The power consumption is expressed qualitatively, as information published in different studies is often not comparable. otherwise can only vary in a dependent way (Ghilardi et al, 2019;Peng et al, 2020;Bonora et al, 2015). Developing such multi-functional lenses requires electrical deformability according to multiple degrees of freedom, thereby challenging the current state of the art of the enabling actuation technologies.…”

“…Structures and principles of operation (left) and photos of examples (right) , for different actuation strategies: (A) schematic of a lens squeezed by an external plunger ring; (A′) shape-memory-alloy-actuated prototype sample, reproduced with permission from ( Choi et al, 2009 ); (B) schematic of a lens pulled by radial extenders; (B′) servo-motors-actuated prototype sample, reproduced with permission from ( Liebetraut et al, 2013 ); (C) schematic of a lens operated by an electrostatic actuator, consisting of stiff annular electrodes that squeeze a soft membrane; (C′) array of prototype samples, reproduced with permission from ( Wang et al, 2017 ); (D) schematic of a lens operated by piezoelectric bending actuators, which deform a thin glass membrane acting on the lens; (D′) commercial product by poLight, adapted from ( Polight, 2021 ); (E) schematic of a lens operated by a transparent DE actuator, which forms the whole lens and increases its own curvature by buckling (note: unidirectional buckling should be facilitated by an initial asymmetry); (E′) prototype sample, reproduced with permission from ( Son et al, 2012 ). (F) schematic of a lens radially compressed by an annular DE actuator; (F′) prototype sample, reproduced with permission from ( Ghilardi et al, 2019 ); (G) schematic of a lens made of and radially stretched by transparent gel electrodes of a DE actuator; (G′) prototype sample, reproduced with permission from ( Liu et al, 2020 ).…”

Bio-Inspired Soft Robotics: Tunable Photo-Actuation Behavior of Azo Chromophore Containing Liquid Crystalline Elastomers

“…Researchers investigated a wide variety of LCEs with diverse liquid crystalline phases including nematic, cholesteric (or helical), smectic phases (smectic A, smectic C, and smectic C *), and discotic and blue phases [14][15][16][17]. These LCEs with diversified liquid crystalline phases have been recognized as potentially effective to more technology-related topics, such as adaptive varifocal micro lenses in miniature electronic devices to soft actuator components of artificial muscle along with biomedical and soft robotic applications [18][19][20][21][22]. Some of the prominently studied polymers are outlined in Figure 2.…”

Refractive Index Change of Cellulose Nanocrystal-Based Electroactive Polyurethane by an Electric Field

“…A tunable optical lens can change the focal distance and refractive index, optical angle, and optical intensity by tuning or reconfiguring the lens material itself (Choi et al, 2017;Ghilardi et al, 2019). Figure 1 shows the concept of a tunable optical lens.…”