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Demonstration of electrically controllable astigmatism for imaging with direction-dependent focusing. Pictures of different targets taken with a commercial camera and a smart lens mounted on it, without any extra lens (schematic drawing at the top). The lens was used in the three possible operation modes: electrical rest (central column) and with actuation along the vertical direction (left-hand column) or horizontal direction (right-hand column). The electrical activation of the segments S1S3 and S2S4 to take the left- and right-hand pictures, respectively, corresponded to an applied nominal electric field of 60 V/µm. The rows present images of the different selected targets: (A) A standard Siemens star target with 72 spokes, used to show astigmatism: when the lens was actuated along one direction, the image was blurred parallel to the direction of the lens squeezing; this directional blurring is more evident towards the center of the star target (zoomed in the second row), where the resolution necessary to resolve the spokes is higher. (B) A target with horizontal and vertical segments, used to show how electrically controlling the directional blurring can practically serve to selectively extract information along the two orthogonal directions. (C) Pictures of zebras, used to show the same effect applied to a non-geometrical pattern, so as to emphasize features having different spatial orientation in a real-life scene; in the central image all the zebra lines are in focus, whilst on the left- and right-hand pictures the vertical or horizontal (respectively) lines are more in focus (green boxes) than the orthogonal ones (red boxes).
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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 m...
Citations
... Graphical illustration depicting a summary of materials, electrical components, fab methods, and the potential applications of SCLs. Inspired by[44][45][46][47][48][49]. ...
... Graphical illustration depicting a summary of materials, electrical components, fabrication methods, and the potential applications of SCLs. Inspired by[44][45][46][47][48][49]. ...
According to the age-old adage, while eyes are often considered the gateway to the soul, they might also provide insights into a more pragmatic aspect of our health: blood sugar levels. This potential breakthrough could be realized through the development of smart contact lenses (SCLs). Although contact lenses were first developed for eyesight correction, new uses have recently become available. In the near future, it might be possible to monitor a variety of ocular and systemic disorders using contact lens sensors. Within the realm of glaucoma, SCLs present a novel prospect, offering a potentially superior avenue compared to traditional management techniques. These lenses introduce the possibility of non-invasive and continuous monitoring of intraocular pressure (IOP) while also enabling the personalized administration of medication as and when needed. This convergence holds great promise for advancing glaucoma care. In this review, recent developments in SCLs, including their potential applications, such as IOP and glucose monitoring, are briefly discussed.
... To change the optical power of a solid body silicone lens, a change of the lens curvature by mechanical deformation has to be induced. A variety of deformation mechanisms are already present in previous works: approaches range from deploying manual actuation [23][24][25][26][27][28][29] over inducing thermal expansion of peripheral components [30][31][32][33] to utilizing electromechanical conversion [34][35][36][37][38][39][40][41]. Yet, exclusively converging lenses are described, most commonly related to a single application purpose and manufactured from Sylgard 184 Silicone Elastomer, a material widely spread throughout published works. ...
By exploiting their inherent elasticity, focus-variable silicone lenses shift their focal length reversibly when deformed. Although biconcave and meniscus lenses contribute to optical systems just as well as biconvex lenses, studies primarily revolve around the latter. Thus, we aim to reveal the focal length shifting potential of all aforementioned lens types. Covering a wide parameter range of varying lens curvature radii, we present a coupled mechanical and optical simulation in which a lens deformation is applied. The results show significant differences in focal length shifting effectiveness for different lens types. Within the domains of specific lens types, trends in this effectiveness emerge for different combinations of curvature radii. Matching these radii when incorporating adaptive silicone lenses in optical systems may guide optics engineers toward more effective system designs through this study.
... 7 However, only a limited number of these methods can do dynamic non-mechanical correction of astigmatism and few of them have been able to achieve large aperture size. [8][9][10][11] One notable design, proposed by Campbell, 12 uses electrically tunable fluidic lenses to achieve dynamic correction of astigmatism, but fluidic lenses are subject to well-known problem of gravitational sagging and surface tension. Another commonly studied method is the use of liquid crystal (LC) spatial light modulators, [13][14][15] but these devices are typically reflective and suffer from reduced image quality due to pixelization. ...
... The solid-state design and flexible materials allow various configurations of the dielectric actuators, e.g., stacked [41,46] and bending actuators [47,48], dielectric membranes [28], pre-stressed annular [49], balloon [25], and rolled cylindrical actuators [50], actuators with liquid electrodes [51] or liquid dielectric [52], and dielectric minimum-energy structures (DEMES) [53,54]. The extensive configurations show applicability in various fields, e.g., robots with dielectric muscles [55] that are able to walk [56], swim [57], jump [58,59] and fly [60], applications in medicine, such as active lenses [61], tremor control [62], prosthetic [63], and soft haptic feedback devices [64], low-power dielectric grippers [54], micro-and nanopositioning systems [65], and vibro-acoustics, such as resonators [26,27], loudspeakers [28], and vibroisolation [27,66]. ...
Fully 3D-printed smart structures have attracted a lot of research interest; new technologies, materials, and methods for 3D-printed functional structures such as sensors, actuators, generators, and batteries are being researched. Recently, a fully 3D-printed, dynamic dielectric actuator fabricated in a single process with multi-material thermoplastic filament extrusion was presented. However, the effects of design parameters on the dynamic electromechanical properties of the printed actuator were not yet researched. To achieve the required performance and dynamic properties of an individualized, 3D-printed actuator, the electromechanical properties must be related to the theoretical design parameters. This requires research into the properties of 3D-printed materials and the electromechanical modeling of the 3D-printed actuator. In this research, an analytical, electromechanical model is introduced, consisting of electrical and mechanical models, and electromechanical coupling. The model consists of basic electrical and dynamic lumped elements, which facilitates the reproducibility and extensibility of the model. The electrical and electromechanical model have been experimentally validated in a free-displacement and a blocked-force boundary condition. This research leads to the identification of design principles and the ability to customize and adapt the 3D-printed actuators to specific dynamic applications.
... Carpi et al. demonstrated a divided DEAs-based lens with electrically tunable astigmatism. [16] Optical aberrations can be dynamically tuned within a range of ≈2-5 wavelengths. Alan et al. demonstrated electrically tunable meta-lenses controlled by DEAs capable of simultaneously performing focal length tuning (>100%) as well as on-the-fly astigmatism and image shift corrections. ...
Electrically reconfigurable lenses capable of focal adjustment and zooming require deformable adaptive optical components. However, existing electroactive optical devices that perform these functions are limited by fluid leakage or require complex mechanical parts. Although polyvinyl chloride (PVC) gel‐based lenses with variable focal lengths and zooming have recently been developed, focal adjustment can only be made in the horizontal axis. Herein, a PVC gel‐based adaptive microlens capable of controlling the focal length and focal point simultaneously in the vertical, horizontal, and diagonal directions without mechanical gears or liquid leakage is presented. By optimizing the characteristics of PVC gels plasticized with three different structured plasticizers, a PVC gel‐based adaptive microlens is fabricated. The produced microlens demonstrates the properties of multidirectional focal adjustment, variable focal length (+33.7 to −15.1 mm) at low input voltages (<300 V), excellent transparency (>90%), fast response (0.10 s at 100 V), silent operation, low power consumption (0.39 mW), and excellent potential for further miniaturization.
... As a result, a coma wavefront error occurs at an equilibrium state. Membrane-based elastomeric lenses [27][28][29][30] are also shape-changing lenses. In contrast to fluidic lenses, they do not suffer from a deformed surface in an unstrained state. ...
For the correction of defocus and astigmatism, mechanical approaches are well known, but there is a need for a non-mechanical, electrically tunable optical system that could provide both focus and astigmatism power correction with an adjustable axis. The optical system presented here is composed of three liquid-crystal-based tunable cylindrical lenses that are simple, low cost, and having a compact structure. Potential applications of the concept device include smart eyeglasses, virtual reality (VR)/ augmented reality (AR) head-mounted displays (HMDs), and optical systems subject to thermal or mechanical distortion. Details of the concept, design method, numerical computer simulations of the proposed device, as well as characterization of a prototype, are provided in this work.
... The crucial part is the synthesis of the solid lens. Conventional techniques usually use molds to make the lens, [28,33] which is often intricate, timeconsuming, and susceptible to defects and/or contaminations. In this regard, we develop a mold-free technique to directly synthesize a plano-convex polyelectrolyte elastomer in-situ on a dielectric elastomer membrane. ...
Lenses are ubiquitously used for imaging. Compared with conventional lenses containing rigid translating components driven by mechanical motors, nonmechanical tunable lenses have been drawing attention owing to their advantages in compactness, lightweight, low power consumption, and fast response. Herein, inspired by the accommodation mechanism of the human eye, an all‐solid electromechanically tunable lens driven by a dielectric elastomer actuator is presented. A soft, stretchable, transparent, and ionically conductive polyelectrolyte elastomer, poly(3‐acrylamidopropyl)trimethylammonium chloride, is synthesized and used as the electrodes, one of which is plano‐convex and the other planar. A mold‐free procedure is elaborated to eliminate the contamination by molding and for facile fabrication. Subject to voltage, the resulting tunable lens achieves a relative change of focal length of ≈46.4%, superior to that of the human eye. The electro–mechano–optical coupling of the lens is modeled and the theoretical predictions agree well with the experimental results. Moreover, the tunable lens responds fast, operates stably in the ambient and desiccated environment, maintains performances over 1000 cycles, and exhibits a shelf‐life longer than 12 weeks. The polyelectrolyte elastomer‐based all‐solid tunable lens promises a potential solution for lightweight, compact, and durable imaging systems.
... 2022; 15 (2): 177-85 Перспективы применения в офтальмологии <умных» контактных линз и переднекамерных электронных имплантов Рис. 7. Многоэлектродные ЭКЛ. Сверху -четырехэлектродная система для исследования распределения слезной жидкости на поверхности глаза [27], снизу -мультисенсорная система с фотодетектором и датчиками температуры и глюкозы [28] [27], bottom -multisensory system with photodetector, temperature and glucose sensors [28] Рис. 8. Эластомерная контактная линза для коррекции астигматизма [29] Fig. 8. Elastomeric contact lens for the correction of astigmatism [29] Э К Л дл я к о р р ек ц и и астигм атизм а и п р есби оп и и и зго товлен ы н а основе ди электрического эластом ера, которы й под воздействием электрического н ап р я ж ен и я м ож ет и зм е н ять свою геом етрию л ибо ц ели ком , л ибо в отдельны х н а п равлениях (рис. 8 ) [29]. ...
... 2022; 15 (2): 177-85 Перспективы применения в офтальмологии <умных» контактных линз и переднекамерных электронных имплантов Рис. 7. Многоэлектродные ЭКЛ. Сверху -четырехэлектродная система для исследования распределения слезной жидкости на поверхности глаза [27], снизу -мультисенсорная система с фотодетектором и датчиками температуры и глюкозы [28] [27], bottom -multisensory system with photodetector, temperature and glucose sensors [28] Рис. 8. Эластомерная контактная линза для коррекции астигматизма [29] Fig. 8. Elastomeric contact lens for the correction of astigmatism [29] Э К Л дл я к о р р ек ц и и астигм атизм а и п р есби оп и и и зго товлен ы н а основе ди электрического эластом ера, которы й под воздействием электрического н ап р я ж ен и я м ож ет и зм е н ять свою геом етрию л ибо ц ели ком , л ибо в отдельны х н а п равлениях (рис. 8 ) [29]. ...
... Сверху -четырехэлектродная система для исследования распределения слезной жидкости на поверхности глаза [27], снизу -мультисенсорная система с фотодетектором и датчиками температуры и глюкозы [28] [27], bottom -multisensory system with photodetector, temperature and glucose sensors [28] Рис. 8. Эластомерная контактная линза для коррекции астигматизма [29] Fig. 8. Elastomeric contact lens for the correction of astigmatism [29] Э К Л дл я к о р р ек ц и и астигм атизм а и п р есби оп и и и зго товлен ы н а основе ди электрического эластом ера, которы й под воздействием электрического н ап р я ж ен и я м ож ет и зм е н ять свою геом етрию л ибо ц ели ком , л ибо в отдельны х н а п равлениях (рис. 8 ) [29]. В обзорах некоторы х ком м ерческих ф и р м (Johnson & Johnson) заявл ен ы К Л для д и н ам и ч еско й к о р р ек ц и и п ресби оп и и , но и н ф о р м ац и и о прототи п ах нет [30]. ...
Systemic and ophthalmological diseases are on the rise the world over, which is, to a large extent, caused by life expectancy growth. Therefore, early diagnosis, screening and monitoringpossibilities of human health parameters is becoming more and more important. Contact lenses, due to being fitted on the eye’s surface, are constantly wetted by tear fluid, and due to present-day microelectronics achievements may be used as a convenient technical means for locating a variety of sensors. The existing prototypes of electronic contact lenses (ECL) are able to monitor intraocular pressure (IOP), levels of glucose, hormones and other biomarkers that reflect the presence of ophthalmic and systemic diseases. The review discusses the publications focused on prototyping results and first laboratory tests. As of today, only one developed device is available for clinical practice (IOP monitoring), others are at different stages of research but have all potentials for being used widely.
... The flexibility of dielectric elastomers makes possible soft robots that are capable of walking [40], swimming [41], and flying [42]. The repeatable response and accuracy of DEAs are utilised, for example, for micro-and nano-positioning systems [43], active lenses [44], haptic feedback [45], and tremor-suppression devices [46]. The dielectric effect makes it possible to have dielectric grippers for object holding without energy consumption (dielectric minimum energy structures -DEMES) [47]. ...
Single-process additive manufacturing provides fully functional 3D-printed structures in a single 3D printer without the need for additional manufacturing processes. The 3D-printed parts can be scaled, individualised, embedded, and combined into multi-functional structures without modifications to the fabrication technology.
This manuscript reports the first demonstration of monolithically 3D-printed stacked dielectric actuators (SDEAs) in a single fabrication process utilising a commercially accessible extrusion 3D printer and thermoplastic filaments. Neither single-layer nor stacked dielectric actuators have been 3D printed with thermoplastic filament extrusion in a single process until now.
To achieve single-process fabrication, this research successfully addresses the main challenges: single-process fabrication of the dielectric layer and electrodes, repeatability and reliability of the 3D-printed thin dielectric layer, and layer stacking.
Four actuators with different active areas and a number of stacked active layers were 3D printed. The functionality of the 3D-printed actuators was demonstrated with dynamic electromechanical characterization in a free-displacement and blocked-force configuration in a broad frequency range (up to 5 kHz).
The actuators show promise for applications that require high-frequency resonators or high controllability in the sub-resonance region.
... A typical DEA comprises of two carbon electrodes located on both surfaces of a stretched elastomer film, which deforms in the planar direction because of Maxwell stress between the electrodes caused by high voltage. Taking advantage of the simple, highly compact, light, and mechanically flexible structure of the DEA, focus-tunable lenses, and the actuation mechanism of the optical axis have been studied [13][14][15][16][17] . ...
... A two-dimensional planar DEA with a single electrode pair and an elastomer or liquid lens at the center of the DEA is a typical structure that changes the curvature of the lens due to radially compressive force to control the focal length 13,16,18 . Planar DEAs with multple electrodes are proposed to regulate focal length, astigmatism, and shift 15,19 . Another approach is to leverage the DEA's three-dimensional structure. ...
The use of dielectric elastomer actuators (DEA) in the development of compact and flexible tunable lens systems for microscopic imaging applications is appealing. However, there are still challenges with imaging system functionality and fabrication process easiness. In this paper, we proposed a multielectrode balloon-type DEA which is capable of tuning both the focus and optical axis of a lens system using 3-degrees-of-freedom movement of the DEA. We first investigated the DEA’s fundamental characteristics and found that effective microscale tangential and axial displacements were obtained up to approximately 10 Hz, and the displacements increased with applied voltage and air pressure. Assuming microscopic imaging application scenarios, we then conducted two-dimensional tracking and focus adjustment tests with a DEA-driven lens system. The result suggested that the position of the optical axis was successfully controlled using the captured image, and target images at different distances were successfully focused and defocused by the axial movement of the DEA.
