Computational Model and Design of the Soft Tunable Lens Actuated by Dielectric Elastomer

2020 ◽  
Vol 87 (7) ◽  
Author(s):  
Jinrong Li ◽  
Xiongfei Lv ◽  
Liwu Liu ◽  
Yanju Liu ◽  
Jinsong Leng
Keyword(s):  
Computational Model ◽  
Failure Modes ◽  
Electrical Breakdown ◽  
Focal Length ◽  
Length Change ◽  
Dielectric Elastomer ◽  
Compact Structure ◽  
Active Film ◽  
Tunable Lenses ◽  
Tunable Lens

Abstract Inspired by the accommodation mechanism of the human eye, several soft tunable lenses have been fabricated and demonstrated the capability of controllable focus tuning. This paper presents a computational model of a dielectric elastomer-based soft tunable lens with a compact structure that is composed of a lens frame, two soft films, and the optically transparent fluid enclosed inside. The two soft films, respectively, serve as the active film and passive film. The active film is a dielectric elastomer film and can be coated with the annular electrode or circular electrode. The deformation of the lenses with both electrode configurations can all be formulated by a boundary value problem with different boundary conditions and be solved as the initial value problem using the shooting method. Two common failure modes of loss of tension and electrical breakdown are considered in the calculation of the lens. The computational results can well fit the experimental data. The focus tuning performances as well as the distributions of stretches, stresses, and electric field in the active films of the lenses with two different electrode configurations are compared. The influences of several parameters on the performances of the lenses are discussed, such that the tunable lens can be designed to have maximum focal length change or to be optimized based on different application requirements.

Experimental Study on Electromechanical Failure of Dielectric Elastomer Actuator

2015 ◽  
Author(s):  
Xuejing Liu ◽  
Shuhai Jia ◽  
Hualing Chen ◽  
Bo Li ◽  
Yu Xing
Keyword(s):  
Breakdown Voltage ◽  
Failure Modes ◽  
Dielectric Breakdown ◽  
Electrical Breakdown ◽  
Dielectric Elastomer ◽  
Theoretical Explanation ◽  
Special Focus ◽  
Stress Effect ◽  
Deformation State ◽  
Boundary Stress

The dielectric elastomer (DE) is an insulating membrane with extra-ordinary properties which can meet various electromechanical failures during the actuation. In the current work, we measured breakdown voltage in DE membrane with special focus on the varying boundary stress during the actuation process. The boundary stress tuned deformation state, causing the membrane to deform out-of-plane before breakdown. A theoretical model is presented, involving the strain-stiffening effect in material and boundary stress effect in geometry, to estimate the dielectric breakdown voltage. The results agree with the experiments. Then, another set of experimental investigation is conducted to study the voltage-induced wrinkling of DE membrane. Steady wrinkles, without an accompany of electrical breakdown are attained and three different failure modes of DE membrane are classified into a phase chart. Finally, a qualitative theoretical explanation on wrinkling mechanism of DE membrane is presented and verified by experimental observations.

Effective Voltage Control of Liquid Crystal Lens for Rapid Focal Length Change

2021 ◽  
Author(s):  
Tsugumi Fukui ◽  
Sota Shimizu ◽  
Keigo Muryobayashi ◽  
Marenori Kawamura ◽  
Susumu Sato ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Focal Length ◽  
Voltage Control ◽  
Length Change ◽  
Effective Voltage ◽  
Liquid Crystal Lens

A Ray Transfer Matrix Model for an Elastomeric Lens

2011 ◽  
Vol 110-116 ◽  
pp. 4145-4148
Author(s):  
Johanna Mae M. Indias ◽  
Clark Kendrick C. Go
Keyword(s):  
Transfer Matrix ◽  
Matrix Model ◽  
Focal Length ◽  
Effective Focal Length ◽  
Length Changes ◽  
Variable Focus ◽  
Tunable Lens

A Ray Transfer Matrix (RTM) of a variable-focus elastomeric fluidic lens is explored and modeled in this paper. A HeNe (543.45nm wavelength) laser is incident on the tunable lens and the effective focal length changes are explored based on this model. Results show that there are two possible focal lengths and that focal lengths are independent of the elastomer thickness.

Design and Analysis of Hemispherical Electrostatic Micro Deformable Focusing Mirror

Volume 3 ◽  
2004 ◽  
Author(s):  
Shang-Wei Tsai ◽  
Meng-Ju Lin
Keyword(s):  
Applied Voltage ◽  
Electrostatic Force ◽  
Focal Length ◽  
Length Change ◽  
Least Square ◽  
Limit Values ◽  
Etching Depth ◽  
Isotropic Etching ◽  
Length Changes ◽  
Structure Layer

For uniform deformation, based on bulk microfabrication with isotropic etching, two types of hemispherical electrostatic micro deformable focusing mirror are designed. One of the focusing mirrors is center-anchored, and the other is circular clamped. Using theory of shells, theoretical solution of deformation under uniform electrostatic force is derived. For more detail analysis of the electrostatic and elastic forces coupling problem, finite element is used to analyze the deformation of the mirror structure. Applying electrostatic force, the profile of micro focusing mirror will be not the spherical and change to become a curve like parabolic surface. Using least square method, the curve is fitted as a parabolic curve and the focal lengths of the focusing micro mirror are obtained. The result shows the focal length without applying electrostatic force can be determined by different micro mirror radius and isotropic etching depth. When the electrostatic forces are applied, the deformation and the focal length change differently between the two types of focusing mirror. For circular clamped micro mirror, the deformation is larger near circular clamped region and uniform in the center regime. Therefore, the relation of focal length and applying voltage is a concave curve with minimum values. That is, the focusing length decreasing as the applying voltage increasing and reaches a limit values. When the applying voltage continues increasing after reaching the minimum value, the focal length increases fast. It also shows the thicker structure layer needs larger applied voltage. But the focal length changes in larger stroke. The pull-in voltage is about 100 volt when the structure layer are both 2 μm. However, the pull-in voltage increases nonlinearly as gap increasing. When the gap increases to 4 μm, the pull-in voltage is about 300 volt. The result shows center-anchored micro mirror has better performance. The deformation is more uniform and the focal length increases nonlinearly as applied voltage increasing. It is found the stroke of focal length is larger and the applied voltage is less. The results shows even when the gap and structure layer is 4 and 2 μm, the pull-in voltage is about 62 volts. However, the stoke changes from 990 to about 1320 μm when applying voltage is from 0 to 60 volts. Therefore, with low applied voltage and large focal length stoke, the center-anchored micro mirror has good performance.

The Effects of Moisture in Metal Oxide on the Mechanical and Electric Properties of Dielectric Elastomer Composites

2020 ◽  
Vol 981 ◽  
pp. 40-44
Author(s):  
Syed Muhammad Aiman Syed Mohd Hakhiri ◽  
Ahmad Farimin Ahmad Osman ◽  
Siti Noor Hidayah Mustapha ◽  
Lau Kwan Yiew ◽  
Shamsul Zakaria
Keyword(s):  
Zinc Oxide ◽  
Titanium Dioxide ◽  
Metal Oxides ◽  
Breakdown Strength ◽  
Electrical Breakdown ◽  
Dielectric Elastomer ◽  
Pdms Film ◽  
Pdms Elastomer ◽  
Elastomer Composites ◽  
Major Factors

Dielectric elastomer (DE) technology are used in several applications for example generator, sensor and actuator. One of the major factors that limits the DE performance is premature electrical breakdown. Compositing is the example that have been reported to increase the breakdown strength. In this study polydimethylsiloxane (PDMS) film will be incorporated with two different fillers which are titanium dioxide (TiO2) and zinc oxide (ZnO). Both metal oxides will be calcined up to 300°C before they are added to the PDMS elastomer as fillers. The results show that the calcined TiO2 and ZnO that incorporated in PDMS films show significant increase of breakdown strengths. Meanwhile, the calcined TiO2 PDMS film give higher breakdown strength as comparison to the calcined ZnO counterpart.

scholarly journals Electrical breakdown of an acrylic dielectric elastomer: effects of hemispherical probing electrode’s size and force

2015 ◽  
Vol 6 (4) ◽  
pp. 290-303 ◽  
Author(s):  
Bin Chen ◽  
Matthias Kollosche ◽  
Mark Stewart ◽  
James Busfield ◽  
Federico Carpi
Keyword(s):  
Electrical Breakdown ◽  
Dielectric Elastomer

The effect of nonlinear material viscosity on the energy harvesting performance of dielectric elastomer generators

2020 ◽  
Vol 31 (7) ◽  
pp. 1029-1038
Author(s):  
Yuanping Li ◽  
Jianyou Zhou ◽  
Liying Jiang
Keyword(s):  
Energy Harvesting ◽  
Conversion Efficiency ◽  
Electromechanical Coupling ◽  
Failure Modes ◽  
Mechanical Energy ◽  
Theoretical Perspective ◽  
Dielectric Elastomer ◽  
Viscosity Model ◽  
Nonlinear Material ◽  
Simulation Results

Dielectric elastomer generators are capable of converting mechanical energy from a variety of sources into electrical energy. The energy harvesting performance depends on the interplay between electromechanical coupling, material viscosity, and multiple failure modes. Experiments also suggest that the material viscosity of dielectric elastomers is deformation-dependent, which makes the prediction of the performance of dielectric elastomer generators more challenging. By adopting the coupled field theory, finite-deformation viscoelasticity theory, and the theory for polymer dynamics, this work investigates the harvested energy and conversion efficiency of dielectric elastomer generators from theoretical perspective. By comparing the simulation results from the nonlinear viscosity model to the experimental data and the simulation results from the linear viscosity model, we further examine the possible factors that may strongly influence the performance of dielectric elastomer generators. It is found that dielectric elastomer generators exhibit higher harvested energy when nonlinear material viscosity is considered. Moreover, by selecting a higher voltage of the power supply for the generator, the conversion efficiency of dielectric elastomer generators can be greatly improved. The theoretical framework in this study is expected to offer some new insights into optimizing the design of dielectric elastomer generators and thus improving their performance.

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