- 标题
- 摘要
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- 实验方案
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Calibration and characteristics of an electrowetting laser scanner
摘要： We present a calibration method to correct for fabrication variations and optical misalignment in a two-dimensional electrowetting scanner. These scanners are an attractive option due to being transmissive, nonmechanical, having a large scan angle (±13.7?), and low power consumption (μW). Fabrication imperfections lead to non-uniform deposition of the dielectric or hydrophobic layer which results in actuation inconsistency of each electrode. To demonstrate our calibration method, we scan a 5 × 5 grid target using a four-electrode electrowetting prism and observe a pincushion type optical distortion in the imaging plane. Zemax optical simulations verify that the symmetric distortion is due to the projection of a radial scanning surface onto a flat imaging plane, while in experiment we observe asymmetrical distortion due to optical misalignment and fabrication imperfections. By adjusting the actuation voltages through an iterative Delaunay triangulation interpolation method, the distortion is corrected and saw an improvement in the mean error across 25 grid points from 43 μm (0.117?) to 10 μm (0.027?).
关键词： Laser scanner,Electrowetting,Scanning characteristic,Calibration
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Electromechanical and Energy Systems (SIELMEN) - Craiova, Romania (2019.10.9-2019.10.11)] 2019 International Conference on Electromechanical and Energy Systems (SIELMEN) - Flexible Polynomial Mathematical Model of a Photovoltaic Power Plant
摘要： We report on a distributed circuit model for multi-color light-actuated optoelectrowetting devices. The model takes into consideration the large variation of absorption coefficient (15×) of photoconductors in the visible spectrum and the nonuniform distribution of photogenerated carriers. With the help of this model, we designed opto-electrowetting devices with optimum thickness of photoconductors. This leads to significant improvement in performance compared with prior reports, including 200× lower optical power, 5× lower voltage, and 20× faster droplet moving speed. This enables the use of commercial projectors to create on-demand “virtual” electrodes for large-scale parallel manipulation of droplets. We have achieved simultaneous manipulation of 96-droplet array. Finally, we have demonstrated parallel on chip detection of Herpes Simplex Virus Type 1 within 45 min using a real-time isothermal polymerase chain reaction assay.
关键词： light-actuated digital microfluidics,electrowetting,polymerase chain reaction (PCR),Droplet microfluidics,optoelectrowetting
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Bulk Power System Dynamics with Varying Levels of Synchronous Generators and Grid-Forming Power Inverters
摘要： The conversion of electrical to mechanical power on a sub-centimeter scale is a key technology in many microsystems and energy harvesting devices. In this paper, we present a type of a capacitive energy conversion device that uses capillary pressure and electrowetting to reversibly convert electrical power to hydraulic power. These microhydraulic actuators use a high surface-to-volume ratio to deliver high power at a relatively low voltage with an energy conversion efficiency of over 65%. The capillary pressure generated grows linearly with shrinking capillary diameter, as does the frequency of actuation. We present the pressure, frequency, and power scaling properties of these actuators and demonstrate that power density scales up as the inverse capillary diameter squared, leading to high-efficiency actuators with a strength density exceeding biological muscle. Two potential applications for microhydraulics are also demonstrated: soft-microrobotics and energy harvesting.
关键词： microsystems,electrocapillary,soft robotics,PDMS,actuator,energy conversion,microfluidics,electrowetting,energy harvesting,porous materials,Microhydraulics,microrobotics
更新于2025-09-16 10:30:52
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Concentric ripples of lubrication film in electrowetting
摘要： When a water drop approaches a solid surface in an ambient oil environment, a thin oil ?lm will be formed between the drop and the solid surface. The lubrication ?lm presents more complex behaviors when the external electrical ?eld varies discretely, and in this work, concentric ripples are found in the thin ?lm under a series of voltage steps, which is obviously different from the ?lm pro?le when the applied voltage is continuously increased. According to the time evolution of the thin ?lm, each voltage step adds a new concentric ripple outside the existing lubrication ?lm. The radial wavelength and the maximum height of each ripple are revealed to have a linear relationship with the amplitude of the corresponding voltage step. The ripples ?nally break into microscopic oil droplets, and the size and the number of the droplets can be predicted with the diameter and the radial wavelength of each ripple.
关键词： oil droplets,concentric ripples,voltage steps,electrowetting,lubrication film
更新于2025-09-16 10:30:52
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[IEEE 2018 Iranian Conference on Electrical Engineering (ICEE) - Mashhad (2018.5.8-2018.5.10)] Electrical Engineering (ICEE), Iranian Conference on - Theoretical and Simulational Study of Electrowetting on Dielectric (EWOD) Effect
摘要： Electrowetting mechanism has been recently employed to enhance the manipulation process in biomedical engineering. In this research, we have described the Electrowetting on thermodynamic Dielectric phenomenon by using classical approach. The droplet motion has been numerically studied by finite element method. The electrowetting mechanism has been investigated by solving the coupled electrostatic and droplet physics. Simulation results revealed 50 V threshold voltage for the system. The droplet velocity increases linearly by increasing the applied electric field and the maximum velocity of 0.04 mm/s has been achieved for 250 V excitation voltage. Based on the results, for the above 250 V there is no velocity increases.
关键词： Digital microfluidics,Electrowetting,Contact angle,Electrowetting on dielectric (EWOD),Surface tension,hydrophobic layer
更新于2025-09-11 14:15:04
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Forming Spacers in Situ by Photolithography to Mechanically Stabilize Electrofluidic-Based Switchable Optical Elements
摘要： Electro-Fluidic Displays (EFD) have been demonstrated to be an attractive technology for incorporation into portable display devices. EFDs have excellent optical ef?ciency and fast switching enabling video content. Ensuring mechanical stability of EFD display cells is a key challenge and essential for developing large area as well as ?exible displays. Although the electro-optic performance of an EFD, unlike a liquid crystal display (LCD), is insensitive to cell-gap, extreme changes in cell-gap can result in irreversible collapse of the cell. Here we use photolithography to develop spacers to prevent cell-gap collapse and provide the required mechanical stability for EFD devices. The spacer is formed directly on the cover plates (ITO/glass) after cell assembly with UV light induced phase separation polymerization in the illuminated area. Phase separation behavior between polar aqueous solution and polymer is closely related to the solubility of acrylate monomers. In this work, polyethylene glycol diacrylate (PEGDA) as cross-linker, 2-hydroxyethyl acrylate (HEA) and acrylic acid or acrylamide as co-monomers are investigated for fabricating the spacers. PEGDA was added to the mixtures in order to increase the mechanical strength of the spacer. The spacers showed excellent performance for cell-gap control in EFD devices.
关键词： mechanical stability,electro?uidic display,phase separation,photopolymerization,electrowetting,spacer
更新于2025-09-10 09:29:36
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11.1: <i>Invited Paper:</i> Electrofluidic displays: Fast switching, Colorful, low power
摘要： Electrofluidic and electrowetting displays have been demonstrated since 2004 [1]. They have been subject to extensive investigation, and many of the problems associated with the electrowetting phenomenon were solved. However, new challenges are emerging, in need of a solution. Electrofluidic displays could (and should) play an important role in a growing collection of display technologies, and will add significantly to our interaction with our environment, but is important to understand exactly how to implement and apply this technology. Maybe even more important: How not to apply it. This paper aims to provide an overview of historic achievements and elaborate on more recent progress, while making clear the exciting possibilities of the technology. It will provide a good insight in the current state of the art, and offer guidelines on the factors influencing contrast, brightness and speed.
关键词： Electrowetting,color,reflectance,video-rate,low power
更新于2025-09-10 09:29:36
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Numerical investigation of electrowetting-based droplet splitting in closed digital microfluidic system: Dynamics, mode, and satellite droplet
摘要： In this paper, the splitting of microdroplet in a closed electrowetting-based digital microfluidic system has been studied via a numerical model. The governing equations for the fluid flow are solved by a finite volume formulation with a two-step projection method on a fixed computational domain. The free surface of the liquid is tracked by a coupled level-set and volume-of-fluid method, with the surface tension at the free surface computed by continuum surface force scheme. Contact angle hysteresis is implemented as an essential component of electrowetting modeling, and a simplified viscous force model is adopted to evaluate the viscous stress based on the Hele-Shaw model. Excellent agreement has been achieved between the numerical and published experimental results. A parametric study has been performed in which the effects of viscous stress, channel height, static contact angles, contact angle hysteresis, and electrode size on the splitting process have been analyzed. Three distinct splitting modes, which are “splitting with satellite droplet,” “normal splitting,” and “splitting cessation,” have been discussed. Based on the competition between the curvature in the z-direction (κz) and that on the x-y plane (κxy), the physical mechanism that separates the splitting into these three modes has been revealed. More importantly, a dimensionless parameter ?κ has been proposed, which can be used for (a) determining the splitting mode and (b) estimating satellite droplet volume for electrowetting-induced droplet splitting process.
关键词： contact angle hysteresis,digital microfluidic system,droplet splitting,electrowetting,numerical model
更新于2025-09-10 09:29:36
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Microdroplet electrowetting actuation on flexible paper-based lab on a chip
摘要： This paper presents the microdroplets electrowetting causing by the voltage actuation on the ?exible lab on a chip. The electrode is made of a thin Aluminium (Al) ?lm while the lab on a chip substrate is made from the cellulose paper, which is ?exible. Consistently in this work the microdroplet samples of 5 μl from Potassium Chloride (KCl) is experimented on top of the electrodes. It is shown that the ?exible paper-based lab on a EW chip has ful?lled the Lippmann’s equation where the higher the voltage supply, the lesser the interfacial tension of droplet. Moreover, the droplet has e?ciently trailed along the track of activated electrodes when using the olive oil as the dielectric layer. The olive oil with dielectric permittivity of 3.2 has given the best displacement and high velocity of the droplet transportation. The best low voltage to move the microdroplet between the two planar electrodes is 12 Vpp under the frequency of 10 Hz.
关键词： Paper-based chip,Flexible device,Aluminium electrode,Electrowetting,Microdroplet
更新于2025-09-09 09:28:46
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Adaptive Liquid Lens Actuated by Droplet Movement
摘要： In this paper we report an adaptive liquid lens actuated by droplet movement. Four rectangular PMMA (Polymethyl Methacrylate) substrates are stacked to form the device structure. Two ITO (Indium Tin Oxide) sheets stick on the bottom substrate. One PMMA sheet with a light hole is inserted in the middle of the device. A conductive droplet is placed on the substrate and touches the PMMA sheet to form a small closed reservoir. The reservoir is filled with another immiscible non-conductive liquid. The non-conductive liquid can form a smooth concave interface with the light hole. When the device is applied with voltage, the droplet stretches towards the reservoir. The volume of the reservoir reduces, changing the curvature of the interface. The device can thus achieve the function of an adaptive lens. Our experiments show that the focal length can be varied from ?10 to ?159 mm as the applied voltage changes from 0 to 65 V. The response time of the liquid lens is ~75 ms. The proposed device has potential applications in many fields such as information displays, imaging systems, and laser scanning systems.
关键词： electrowetting,liquid,lens
更新于2025-09-09 09:28:46