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Design and Fabrication of Nonconventional Optical Components by Precision Glass Molding

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Design and Fabrication of Nonconventional Optical Components by Precision Glass Molding DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By Peng He Graduate Program in Industrial and Systems Engineering The Ohio State University 2014 Dissertation Committee: Dr. Allen Y. Yi, Advisor Dr. Jose M. Castro Dr. L. James Lee Copyright by Peng He 2014 Abstract Precision glass molding is a net-shaping process to fabricate glass optics by replicating optical features from precision molds to glass at elevated temperature. The advantages of precision glass molding over traditional glass lens fabrication methods make it especially suitable for the production of optical components with complicated geometries, such as aspherical lenses, diffractive hybrid lenses, microlens arrays, etc. Despite of these advantages, a number of problems must be solved before this process can be used in industrial applications. The primary goal of this research is to determine the feasibility and performance of nonconventional optical components formed by precision glass molding. This research aimed to investigate glass molding by combing experiments and finite element method (FEM) based numerical simulations. The first step was to develop an integrated compensation solution for both surface deviation and refractive index drop of glass optics. An FEM simulation based on Tool-Narayanaswamy-Moynihan (TNM) model was applied to predict index drop of the molded optical glass. The predicted index value was then used to compensate for the optical design of the lens. Using commercially available general purpose software, ABAQUS, the entire process of glass molding was simulated to calculate the surface deviation from the adjusted lens geometry, which was applied to final mold shape modification. A case study on molding of an aspherical lens was ii conducted, demonstrating reductions in both geometry and wavefront error by more than 60%. In addition, mold materials and mold fabrications were explored as molds are crucial for fabrication of different freeform optics. The research for the first time demonstrated the use of graphene-coated silicon as an effective and high-performance mold material for precision glass molding. It was shown experimentally that Si-glass adhesion could be completely avoided by using the carbide-bonded graphene coating on Si molds. A glass Fresnel lens and a micro lens arrays using graphene-coated Si molds were molded and tested. Two other novel mold materials, i.e., bulk material glass and copper nickel alloy, were also investigated. Prototypes of optical components were molded using these two materials. The molded lens glass samples were measured by 3D profiler, and the optical performance of the molded lens was also evaluated by lab optical setup. The applications of both of the mold materials were also discussed. Finally, precision glass molding techniques are discussed for two different applications, a diffractive hybrid lens molded by a visible optical glass and a micro lens array molded by infrared (IR) glass. The diffractive hybrid lens was designed to compensate for chromatic aberration. The diffractive efficiency and achromatic focal shift of the molded lens were measured using lab setup, demonstrating a match between the molded lens and optical design. On the other hand, an infrared glass micro lens array and optical gratings were also molded and evaluated using similar approach. The geometry and optical evaluation iii of these molded glass applications showed that precision glass molding are capable of fabricate non-convectional optical components with designed functionality. iv Dedication This document is dedicated to my family. v Acknowledgments I would like first to thank my advisor, Dr. Allen Y. Yi, for providing me the opportunity to work in the field of precision optical engineering. I appreciate his insight, suggestions and assistance during my research work. I want to thank Dr. Yi for his patient guidance on my publications, where his attitude of striving for excellence has given tremendous influence to me. Also, I am indebted to my dissertation committee members, Prof. Jose M. Castro and Prof. L. James Lee for their suggestions, comments and support of my research. I want thank my previous senior lab fellows, Dr. Yang Chen and Dr. Lijuan Su, who unreservedly taught me the knowledge of glass forming science and simulation related skills. Special thanks should be addressed to Dr. Lei Li, who collaborated with me and provided great help on Graphene project. Without the help of those senior lab fellows, my research project wouldn’t have a good start. I sincerely give my appreciations to my two 9-year classmates, Likai Li and Hui Li, who collaborated with me on various projects in the past few thousands of days and nights. I am also grateful to work with other excellent labmates, Dave McCray, Ziwei Zhao, Hao Zhang, Bo Tao, Neil Naples and Amin Moghaddas. vi I acknowledge the help from Joshua Hassenzahl, lab supervisor at the department of integrated systems engineering, for assisting in mold fabrication and many fixtures used in my research. I also want to thank Prof. Jerald Brevick, graduate studies chair, for his support on my academic progresses. I want to thank Prof. Fritz Klocke, Dr. Olaf Dambon, Dr. Fei Wang, Mr. Gang Liu and Mr. Yang Wang at Fraunhofer Institute for Production Technology (IPT), Aachen, Germany, for providing experimental support and assistance during my visit to IPT. Finally, I want to express the deepest appreciation for my wife, Jia Li, for her faith and love to me. The mutual intellectual and moral supports between us are my source of power in pursuit of excellence. I am also indebted to my parents, sister, grandparents and parents-in-law for their endless support in my life. vii Vita July, 1986 .......................................................Born, Xianyang, China July, 2009 .......................................................B.S. Mechanical Engineering, University of Science and Technology of China, Hefei, China June, 2011 to July, 2011 ................................Visiting Scholar, Fraunhofer Institute for Production Technology (IPT), Aachen, Germany May, 2014 ......................................................M.S. Industrial Engineering, the Ohio State University, Columbus, Ohio Sep, 2009 to present ......................................Graduate Research Associate, Department of Industrial and Systems Engineering, The Ohio State University, Columbus, Ohio viii Publications Journal Publications: P. He, L. Li, J.Yu, L. J Lee and A. Y. Yi “Compression molding of freeform optics using diamond machined Si mold”, Manufacturing letters, 2014;2:17–20. P. He, L. Li, J. Yu, W. Huang, Y.Yen, L. J. Lee, A. Y. Yi “Graphene coated Si mold for molded glass optics”, Optical Letters，2014;53:98–103 P. He, F. Wang, L. Li, K. Georgiadis, O. Dambon, F. Klocke, and A. Y. Yi, “Development of a low cost high precision fabrication process for glass hybrid aspherical diffractive lenses,” J. Opt., vol. 13, no. 8, p. 085703, Aug. 2011. L. Li, P. He, F. Wang, K. Georgiadis, O. Dambon, F. Klocke, and A. Y. Yi, “A hybrid polymer–glass achromatic microlens array fabricated by compression molding,” J. Opt., vol. 13, no. 5, p. 055407, May 2011. B. Tao, P. He, L. Shen, “Measurement of Residual Stresses in Molded Glass Lenses”, Advanced Materials Research Vol. 902 (2014) pp 144-147 B. Tao, P. He, L. Shen, A. Y. Yi “Annealing of Compression Molded Aspherical Glass Lenses”, Journal of Manufacturing Science and Engineering， J. Manuf. Sci. Eng. 136(1), 011008 (2013) doi:10.1115/1.4025395 L. Su, P. He, and A. Y. Yi, “Investigation of glass thickness effect on thermal slumping by experimental and numerical methods,” Journal of Materials Processing Technology, vol. 211, no. 12, pp. 1995–2003, (2011) L. Su, F.Wang, P. He, O. Dambon, F. Klocke, A. Y. Yi “An Integrated Solution for Mold Shape Modification in Precision Glass Molding to Compensate Refractive Index Change and Geometric Deviation” , Optics and Laser in Engineering, 53, 98– 103 (2014). ix B. Tao, L. Shen, P. He, and A. Yi, “Quantitatively Measurement and Analysis of Residual Stresses in Molded Aspherical Glass Lenses” , The International Journal of Advanced Manufacturing Technology, June 24, pp1–8 (2014) Conference proceedings and presentations: P. He, P. Xie, L. J. Lee, and A. Y. Yi. “Rapid Micro-embossing and injection molding.” OSA Technical Digest , Optical Fabrication and Testing, Kohala Coast, Hawaii, June, 2014 P. He, L. Li,J. Yu,W. Huang, Y-C. Yen, J.L. Lee, A. Y. Yi, “Graphene Coated Si Mold for Precision Glass Optics Molding , ASPE Annual Meeting, St. Paul, MN, Oct, 2013 P. He, L. Li, J. F. Yu, L. J. Lee, A. Y. Yi, “Ultraprecision Mold Fabrication For Polymer and Glass Molding,” International Symposium on Advanced Molding Technology and Materials Processing, Planery Talk, Ninghai, China, July 2-3 ,2013. B. Tao, P. He, L.Shen, “Measurement of Residual Stresses in Molded Glass Lenses”, International Conference on Manufacturing Engineering and Technology for Manufacturing Growth,Miami,FL, Jan, 2014 P. Xie, E. D. Cabrera, P. Zhang, Y. Yen, P. He, D. Gallego-Perez, L. Chang, A. Y. Yi, J. Castro,and L. J. Lee.“Rapid micro-embossing and injection molding using molds with carbide-bonded graphene coating”, 30th International Conference of the Polymer Processing Society (PPS-30), Cleveland, Ohio, June 8-12, 2014 F. Klocke, O. Dambon, L. J.
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