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Bio-Inspired Reconfigurable Elastomer-Liquid Lens: Design, Actuation And

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Bio-Inspired Reconfigurable Elastomer-Liquid Lens: Design, Actuation And Bio-inspired Reconfigurable Elastomer-liquid Lens: Design, Actuation and Optimization DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Kang Wei Graduate Program in Biomedical Engineering The Ohio State University 2015 Dissertation Committee: Professor Yi Zhao, Advisor Professor Derek Hansford Professor Thomas Raasch Copyright by Kang Wei 2015 Abstract Mother Nature presents beautiful designs for imaging with high spatial resolution, depth cues, and/or wide field of view (FOV). With the large eye diameter and densely populated photoreceptors on the retina, the human camera-eye, for example, captures image with spatial resolution as high as 1/60º. It also enables auto-focus by accommodation mechanism (about 12 diopters at maximum), and depth sensation using binocular disparity given the inter-pupil separation of about 55 mm, two premium attributes that stand out among all advanced vision systems. Compound eye, on the other, excels in panoramic imaging (FOV up to 180º), thanks to their densely populated ommatidia (individual image sampling units) arranged on a hemispherical substrate. At a sacrifice, its spatial resolution is typically larger than 1º. Recent decades have seen a large number of optical designs that incorporate the structural characteristics of human camera-eye or compound eye. Representative examples are elastomer-liquid lens, and artificial apposition compound eye camera. The elastomer- liquid lens is usually driven by a complex actuation mechanism, and achieves a limited dioptric range and undesirable optical performances at large refractive powers. The adoption of the compound eye camera, on the other hand, is inhibited by its poor spatial resolution, lack of auto-focusing, and sophisticated fabrication and assembly processes. ii The gist of this thesis is to introduce novel optical designs to solve the abovementioned issues by leveraging smart materials and reconfigurability of optofluidics. First, a hybrid eye that incorporates the structural characteristics of both human and insect visions is described, where an elastomer-liquid lens array with variable focusing power and optical axis is developed. Its ability to acquire image with a large FOV and depth cues is demonstrated. Secondly, a compound elastomer-liquid apparatus that reconfigures from a singlet with a large aperture to binoculars with small apertures sharing a single optical channel is developed. The stacked lens design allows for the access to both two dimensional imaging by adaptive focusing, and three-dimensional imaging by binocular depth perception at a constrained space. Thirdly, a driving mechanism based on electroactive artificial muscle materials is studied, which actuates an elastomer-liquid lens at a large dioptric range and reduced voltage. Finally, the peripheral and central resolution of an elastomer-liquid lens enveloped by a membrane with aspherical cross-section is compared to that of a lens by a planar membrane. The lens with aspherical membrane results in significantly smaller field curvature, and thus much better peripheral and central resolving powers at high diopters. These studies provide insight into elastomer-liquid lens design and configuration, actuation, and optimization, which finds immediate use in a wide range of demanding applications where adaptive focusing with high resolution, large FOV, and/or multi-modes is at a premium. iii Dedication This dissertation is dedicated to my loving and supportive wife, Rongli Xiang, our 7-month brilliant and considerate baby boy, Jeremy Yumo Wei, and to my always encouraging, ever thoughtful parents, Xianping Wei and Hong Liu. iv Acknowledgments I would like to thank all the people who provided me with vision, confidence, and assistance throughout the Ph.D. program. Without you, I would never been able to go this far. This research was performed under the guidance of my advisor, Professor Yi Zhao, to whom I would like to express my gratitude, for his consistent inspiration, motivation and academic support. With his timely and incisive advice, I was able to pinpoint the “Yes” from a thousand “No’s”. I am indebted to my former and current labmates, Dr. Hansong Zeng, Dr. Qian Wang, Xu Zhang, Nicholas Domicone, Matthew Rudy, Andrew Wang, Hanyang Huang, Lin Qi, and Michael Bush, and to my schoolmates, Dr. Jiwei Huang and Dr. Leilei Zhang, for their support in experiments, professional development and life. I am grateful to Professor Thomas Raasch, who opened the door of my explorations in lens design and adaptive optics, and was willing to participate in my final defense committee at the last moment. Many thanks to Dr. Ronald Xu, who mentored me on SPIE Student Chapter leadership. Special thanks also goes to Professor Derek Hansford for his continuing service on both my candidacy and dissertation committee. v In addition, I would like to thank Dr. Robert Batchko and his colleagues, Jei-Yin Yiu and Sam Robinson at Holochip Corporation, for developing my skillset in optics during summer internship in 2014. Finally, I would like to express my sincerest appreciation to my wife, Rongli Xiang, who was always there cheering me up and stood by me through the good and bad times. vi Vita 2008................................................................B.S. Biomedical Engineering, Chongqing University, China 2010................................................................M.S. Biomedical Electronics and Information Technology, Chongqing University, China 2010 to 2011 ..................................................University Fellow, Department of Biomedical Engineering, The Ohio State University 2011 to 2012 ..................................................Howard Hughes Med Into Grad Scholar, Wexner Medical Center, The Ohio State University 2012 to 2013 ..................................................Graduate Research Associate, Department of Biomedical Engineering, The Ohio State University 2013 to present ..............................................Graduate Pelotonia Fellow, Comprehensive Cancer Center - James, The Ohio State University vii Publications Journal Articles Wei, K., Rudy, M. S., & Zhao, Y. (2014). Systematic investigation of the benchtop surface wrinkling process by corona discharge. RSC Advances, 4(103), 59122-59129. Wei, K., Zeng, H., & Zhao, Y. (2014). Insect–Human Hybrid Eye (IHHE): an adaptive optofluidic lens combining the structural characteristics of insect and human eyes. Lab on a Chip, 14(18), 3594-3602. Wei, K., Domicone, N. W., & Zhao, Y. (2014). Electroactive liquid lens driven by an annular membrane. Optics letters, 39(5), 1318-1321. Wei, K., Zeng, H., & Zhao, Y. (2013). Substrate material affects wettability of surfaces coated and sintered with silica nanoparticles. Applied Surface Science, 273, 32-38. Wei, K., Huang, H., & Zhao, Y. (2015). A focus-tunable liquid lens encapsulated by a membrane with aspherical cross-section for improving central and peripheral resolutions at high diopters. Light Science and Applications, submitted. Conference Proceedings (Full paper) Wei, K., Domicone, N., Wang, A., Rudy, M., & Zhao, Y. (2014). An on-board microfluidic pump driven by magnetic stir bars. Paper presented at the Proceeding of the 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS 2014), San Antonio, TX, USA, in press. Wang, Q., Wei, K., & Zhao, Y. (2014). A microdevice to investigate the synergistic effect of passive and active mechanical stimulations on cell alignment. Paper presented at the Proceeding of the 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS), San Antonio, TX, USA, in press. Wei, K., Domicone, N. W., & Zhao, Y. (2014). A tunable liquid lens driven by a concentric annular electroactive actuator. Paper presented at the Micro Electro Mechanical Systems (MEMS), 2014 IEEE 27th International Conference on, San Francisco, CA, USA. viii Wei, K., & Zhao, Y. (2014). Fabrication of anisotropic and hierarchical undulations by benchtop surface wrinkling. Paper presented at the Micro Electro Mechanical Systems (MEMS), 2014 IEEE 27th International Conference on, San Francisco, CA, USA. Wei, K., & Zhao, Y. (2013). A three-dimensional deformable liquid lens array for directional and wide angle laparoscopic imaging. Paper presented at the Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International Conference on, Taipei, Taiwan. Wei, K., & Zhao, Y. (2012). Fast and versatile fabrication of PDMS nanowrinkling structures. Paper presented at the Proceeding of the 16th Internatinoal Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS 2012), Okinawa, Japan. Fields of Study Major Field: Biomedical Engineering iii Table of Contents Abstract ............................................................................................................................... ii Dedication .......................................................................................................................... iv Acknowledgments............................................................................................................... v Vita .................................................................................................................................... vii Publications ...................................................................................................................... viii Fields of Study ..................................................................................................................
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