A 4 bit digital liquid lens for variable focal length

Lee, Dong Woo; Cho, Young-Ho

doi:10.1088/0960-1317/20/3/035029

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Another approach is the MOEMS liquid pneumatic lens. [5][6][7][8][9][10][11][12][13] In this type of element, pumping a liquid in and out of an optically transparent cavity with an elastic membrane changes the curvature in order to control focus. The liquid-filled lens requires a mechanical pumping system and may exhibit vibration sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Improved micro-optoelectromechanical systems deformable mirror forin vivooptical microscopy

Moghimi

Wilson

Dickensheets

2012

J. Micro/Nanolith. MEMS MOEMS

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Micro-optoelectromechanical systems (MOEMS) deformable mirrors are being developed for focus control in miniature optical systems including endoscopic microscopes and small form-factor camera lenses. A new process is described to create membrane mirrors made from the photoset polymer SU-8. The SU-8 also serves as the adhesive layer for wafer bonding, resulting in a simple, low cost fabrication process. The process details and the optical properties of the resulting focus control mirrors, which have a diameter of 2 mm, a stroke in excess of 8 μm and very low residual aberration, are described. Multiple actuation electrodes allow active control of more than 1.4 μm peak-to-peak of wavefront spherical aberration. The MOEMS mirror is demonstrated in a confocal microscope in which it provides focus control during capture of in vivo images. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Section: Introductionmentioning

confidence: 99%

Improved micro-optoelectromechanical systems deformable mirror forin vivooptical microscopy

Moghimi

Wilson

Dickensheets

2012

J. Micro/Nanolith. MEMS MOEMS

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“…3,4 Several group have reported the focal length tuning of single PDMS lenses, using electroactive polymers, pneumatic (analog and digital) and thermal. [5][6][7][8] Fewer publications concern lens arrays whose focal length can be tuned during operation. Zappe's group has reported pneumatic tuning of PDMS lens arrays.…”

Section: Introductionmentioning

confidence: 99%

Array of lenses with individually tunable focal-length based on transparent ion-implanted EAPs

Niklaus

Rosset

Shea

2010

Electroactive Polymer Actuators and Devices (EAPAD) 2010

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We report on the fabrication and characterization of 2x2 arrays of mm-diameter PDMS lenses whose focal length can be electrically tuned. Dielectric elastomer actuators generally rely on carbon powder or carbon grease electrodes, which are not transparent, precluding the polymer actuator from also being a lens. However compliant electrodes fabricated by low-energy ion implantation are over 50% transparent in the visible, enabling the polymer lens to simultaneously be an actuator. We have developed a chip-scale process to microfabricate lens arrays, consisting of a molded socket bonded to a Pyrex chip supporting 4 membrane actuators. The actuators are interconnected via an incompressible fluid. The Pyrex chip has four through-holes, 1 to 3 mm in diameter, on which a 30 µm thick Polydimethysiloxane (PDMS) layer is bonded. The PDMS layer is implanted on both sides with 5 keV gold ions to define the transparent electrodes for EAP actuation. Applying a voltage to one of the lens/actuators leads to an area expansion and hence to a change in radius of curvature, varying the focal length. We report tuning the focal length from 4 mm to 8 mm at 1.7 kV, and present changes in optical transmission and membrane stiffness following gamma and proton irradiation.

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“…The contact angle hysteresis is mostly related to the roughness and non-homogeneity of solid surface but still origin of the phenomena has not been completely explored. The required force to move the drop on the surface is defined by [83,84]: [9] Where θ r and θ a are respectably receding contact angle and advancing contact angle, w is width of the drop bottom perpendicular to the direction of sliding force: [10] Where the R is radius of drop that ideally deepens on static contact angle and volume of drop [85]: [11] According to Equation 9 in order to minimize effect of sliding force there are two ways:…”

Section: Electrowetting On Dielectric (Ewod)mentioning

confidence: 99%

Contribution to liquid lens technology

Ahmadi Zeidabadi

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The interest on microfluidic systems based on electrowetting-on-dielectric (EWOD) and the miniaturization of such integrated devices, has increased significantly mainly due to the advent of mass market applications such as lab-on-chip, liquid lenses and reflective displays. The main objective of this work focuses on the scientific and technological challenges that the fabrication and optimization of liquid lens faces. Those are mainly related to the materials used and their associated fabrication techniques, in order to have stable devices with high performance for long term functionality. The work reported here contributes the research to reduce the actuation voltage and to increase stability and reliability of electrowetting devices such as liquid lenses at laboratory scale. We address various aspects related to liquid lenses: (a), improvement of the hydrophobic layer deposition process leading contact angle recovery enhancement, (b) investigation of the dielectric materials and deposition techniques to reduce the required applied voltage (c) specific design of electrodes for 2D movement of the liquid lens, and (d) investigation of nonaqueous liquids to improve the dynamic behavior and long term cycling functionality. (e) An attempt is made to develop behavioral models that can explain EWOD phenomena with an electronic circuit software. El interés en los sistemas microfluídicos basados en electrohumectación sobre un dieléctrico (electrowetting-on-dielectric, EWOD) y la miniaturización de dichos dispositivos integrados, ha aumentado significativamente, principalmente debido a la llegada de aplicaciones del mercado de masas, como lab-on-chip, lentes líquidas y pantallas reflectantes. El objetivo principal de este trabajo se centra en los retos científicos y tecnológicos de la fabricación y la optimización de una lente líquida. Principalmente, los que están relacionadas con los materiales utilizados y sus técnicas de fabricación asociadas, con el fin de tener dispositivos estables con un alto rendimiento para la funcionalidad a largo plazo. Este trabajo describe la investigación llevada a cabo para reducir la tensión de accionamiento y para aumentar la estabilidad y la fiabilidad de los dispositivos EWOD, tales como lentes líquidas, a escala de laboratorio. Los principales aspectos relacionados con lentes líquidas trabajados en esta tesis son los siguientes: (a) la mejora del proceso de depósito de la capa hidrofóbica que determina el ángulo de contacto y mejora su recuperación, (b) la investigación de los materiales dieléctricos y técnicas de depósito para reducir la tensión aplicada, (c) el diseño específico de electrodos para el movimiento en 2D de la lente líquida, y (d) la investigación de los líquidos no acuosos para mejorar el comportamiento dinámico y la funcionalidad en frecuencia a largo plazo. (e) También se ha iniciado el desarrollo de modelos de comportamiento que puedan explicar fenómenos EWOD con un software de circuitos electrónicos.

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A 4 bit digital liquid lens for variable focal length

Cited by 4 publications

References 11 publications

Improved micro-optoelectromechanical systems deformable mirror forin vivooptical microscopy

Improved micro-optoelectromechanical systems deformable mirror forin vivooptical microscopy

Array of lenses with individually tunable focal-length based on transparent ion-implanted EAPs

Contribution to liquid lens technology

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