近幾年來，軟性電子技術成為世界各國爭相發展的重點技術之一，其具有重量輕、製程容易、大面積、可撓曲、耐衝擊以及成本低等優點，使電子產品的應用領域得以進一步的擴展。然而在軟性電子的發展中，以顯示器及感測器的發展速度最快，原因為目前顯示器的需求與應用日益增加，觸控面板亦成為未來的趨勢。本論文研究觸覺感測器的設計與製作，並期望能應用於軟性顯示器，將此感測器當作一控制搖桿，藉以操控三維虛擬影像。
本論文設計一觸覺感測器，設計概念為以四個電極為一個感測單元，其特點為全透明、可撓曲、可使用任何物體觸碰、並支援多點觸控；功能可檢測正向力、側向力、拉力等功能，本論文亦提出「摩擦力協助(Friction-Assisted)」的拉力概念，使操作者可以摩擦力的方法施加拉力。最終期望將本元件應用於軟性顯示器上，將之當作一控制搖桿，並利用本論文提出之拉力感測機制，操控三維虛擬影像，將影像作平移、旋轉、推入以及拉出等動作，使得人類與影像之互動更接近人體實境的效果。
本研究首先先對元件建模，並以軟體模擬元件之受力結果，再利用黃光微影、蝕刻、濺鍍、翻模、對準以及黏合等製程技術，完成觸覺感測器。本論文亦設計並實現後端讀出電路，最後架設實驗架構量測元件，以驗證觸覺感測器的設計概念。而本論文亦分析觸覺感測器在曲面下之特性，探討曲率半徑與初始電容值之關係，以及元件在曲面下之靈敏度變化，對可撓性做更加深入的探討。

Recently, flexible electronics technology becomes more and more attractive in industry, due to the advantages of light weight, easy fabrication, large area, flexible, sustain shock and low cost. The applications of flexible electronic have been widely found, especially in flexible display and tactile sensor. Therefore, we designed and fabricated a novel tactile sensor for a joystick and hope it can be applied on flexible display to control 3D virtual image.
In this thesis, a novel flexible and transparent tactile sensor which consists four capacitors in one sensing cell, is proposed with the desired properties: flexible, transparent, able to be touched by any objects and support multi-touch. The concept of the developed sensor is able to detect normal, shear, and pulling forces. The pulling force can be detected since friction-Assisted pulling force is implemented in the proposed sensor. The long-term goal of this study is using the normal, shear, and pulling force to control the 3D image and is applied to a flexible display.
The model of the sensor is first established, then the commercial software is utilized to simulate the behavior and to test the performance of the device. Fabrication such as photolithography, deeply etching, sputter, demold, alignment and bonding are processed to produce the sensor. The readout circuit is designed and realized, and the experiment is setup to verify the design concept of the proposed sensor. Furthermore, the bending characteristic of flexible tactile sensor is also analyzed. The relationship between bending radii and initial capacitance is studied and the performance of tactile sensor under different bending curvature is also investigated.

[1] W. S. Wong and A. Salleo, “Flexible Electronics: Materials and Applications,” Springer Science+Business Media LLC, 2009.
[2] A. Frucci. (2011). Nokia's flexible smartphone prototype is pretty crazy. Retrieved October 29, 2011, from the World Wide Web: http://dvice.com/archives/2011/10/nokias-flexible.php
[3] 工研院應用軟性電子基板，所開發出之6吋彩色可撓曲AMOLED顯示器，http://www.compotech.com.tw/articleinfo.php?id=16339
[4] H. Liu and R. M. Crooks, “Paper-based electrochemical sensing platform with integral battery and electrochromic read-out,” Analytical chemistry, vol. 84, pp. 2528-2532, 2012.
[5] L. Nyholm, G. Nyström, A. Mihranyan, and M. Strømme, “Toward flexible polymer and paper-based energy storage devices,” Advanced Materials, vol. 23, pp. 3751-3769, 2011.
[6] Q. C. Hsu, J. J. Hsiao, T. L. Ho, and C. D. Wu, “Fabrication of photonic crystal structures on flexible organic light-emitting diodes using nanoimprint,” Microelectronic Engineering, vol. 91, pp. 178-184, 2012.
[7] G. Gu, P. E. Burrows, S. Venkatesh, S. R. Forrest, and M. E. Thompson, “Vacuum-deposited, nonpolymeric flexible organic light-emitting devices,” Optics Letters, vol. 22, pp. 172-174, 1997.
[8] C. N. Chen, C. T. Huang, C. L. Chao, M. T. K. Hou, W. C. Hsu, and J. A. Yeh, “Strengthening for sc-Si solar cells by surface modification with nanowires,” Journal of Microelectromechanical System, vol. 20, pp. 549-551, 2011.
[9] K. M. Coakley and M. D. McGehee, “Conjugated polymer photovoltaic cells,” Chemistry of Materials, vol. 16, pp. 4533-4542, 2004.
[10] L. Dong, R. Yue, and L. Liu “Fabrication and characterization of integrated uncooled infrared sensor arrays using a-Si thin-film transistors as active elements,” Journal of Microelectromechanical System, vol. 14, pp. 1167-1177, 2005.
[11] X. Duan, C. Niu, V. Sahi, J. Chen, J. W. Parce, S. Empedocles and J. L. Goldman, “High-performance thin-film transistors using semiconductor nanowires and nanoribbons,” Nature, vol. 425, pp. 274-278, 2003.
[12] A. W. Martinez, S. T. Phillips, B. J. Wiley, M. Gupta, and G. M. Whitesides, “FLASH: A rapid method for prototyping paper-based microfluidic devices,” Lab on a Chip, vol. 8, pp. 2146-2150, 2008.
[13] Z. Nie, C. A. Nijhuis, J. Gong, X. Chen, A. Kumachev, A. W. Martinez, M. Narovlyansky, and G. M. Whitesides, “Electrochemical sensing in paper-based microfluidic devices,” Lab on a Chip, vol. 10, pp. 477-483, 2010.
[14] S. R. Forrest, “The path to ubiquitous and low-cost organic electronic appliances on plastic,” Nature, vol. 428, pp. 911-918, 2004.
[15] C. D. Sheraw, L. Zhou, J. R. Huang, D. J. Gundlach, and T. N. Jackson, “Organic thin-film transistor-driven polymer-dispersed liquid crystal displays on flexible polymeric substrates,” Applied Physics Letters, vol. 80, pp. 1088-1090, 2002.
[16] 經濟部技術處，軟性電子，產業技術白皮書，民國九十七年。
[17] B. Comiskey, J. D. Albert, H. Yoshizawa, and J. Jacobson, “An electrophoretic ink for all-printed reflective electronic displays,” Nature, vol. 394, pp. 253-155, 1998.
[18] S. M. Venugopal and D. R. Allee, “Integrated a-Si:H source drivers for 4 QVGA electrophoretic display on flexible stainless steel substrate,” Journal of Display Technology, vol. 3, pp. 57-63, 2007.
[19] B. Sun, K. Zhou, Y. Lao, J. Heikenfeld, and W. Cheng, “Scalable fabrication of electrowetting displays with self-assembled oil dosing,” Applied Physics Letters, pp. 011106, 2007.
[20] J. Heikenfeld, K. Zhou, E. Kreit, B. Raj, S. Yang, B. Sun, A. Milarcik, L. Clapp, R. Schwartz, “Electrofluidic displays using Young-Laplace transposition of brilliant pigment dispersions ,” Nature Photonics, vol. 3, pp. 292-296, 2009.
[21] P. Andersson, R. Forchheimer, P. Tehrani, and M. Berggren, “Printable all-organic electrochromic active-matrix displays,” Advanced Functional Materials, vol. 17, pp. 3074-3082, 2007.
[22] W. A. Gazotti, G. C. Miceli, A. Geri, A. Berlin, and M. A. Paoli, “An all-plastic and flexible electrochromic device based on elastomeric blends,” Advanced Materials, vol. 10, pp. 1522-1525, 1998.
[23] C. Y. Lo, O. H. Huttunen, J. H. Keinänen, J. Petäjä, H. Fujita, and H. Toshiyoshi, “MEMS-controlled paper-like transmissive flexible display,” Journal of Microelectromechanical System. vol. 19, pp. 410-418, 2010.
[24] D. Felnhofer, K. Khazeni, M. Mignard, Y. J. Tung, J. R. Webster, C. Chui, and E. P. Gusev, “Device physics of capacitive MEMS,” Microelectronic Engineering, vol. 84, pp. 2158-2164, 2007.
[25] J. M. Xin, and Y. B. Jin, “Structure and application of polarizer film for thin-film-transistor liquid crystal displays,” Displays, Vol. 32, Is. 2, pp. 49-57, 2011.
[26] H. Fujikake, H. Sato, and T. Murashige, “Polymer-stabilized ferroelectric liquid crystal for flexible displays,” Displays, Vol. 25, Is. 1, pp. 3-8, 2004
[27] M. H. Ahn, E. S. Cho, S. J. Kwon, “Effect of the duty ratio on the indium tin oxide (ITO) film deposited by in-line pulsed DC magnetron sputtering method for resistive touch panel,” Applied Surface Science, vol. 258, pp. 1242-1248, 2011.
[28] W. Y. Chang, T. H. Fang, H. J. Lin, Y. T. Shen, and Y. C. Lin, “A Large Area Flexible Array Sensors Using Screen Printing Technology, ” Journal of Display Technology, vol. 5, pp. 178-183, 2009.
[29] H. J. Kwon and W. C. Choi, “Design and Fabrication of a Flexible Three-axial Tactile Sensor Array Based on Polyimide Micromachining,” Microsystem Technologies, vol. 16, pp. 2029-2035, 2010.
[30] A. Wisitsoraat, V. Patthanasetakul, T. Lomas, and A. Tuantranont, “Low cost thin film based piezoresistive MEMS tactile sensor,” Sensors and Actuators A: Physical, vol. 139, pp. 17-22, 2007.
[31] C.S. Park, J. Park, and D.W. Lee, “A piezoresistive tactile sensor based on carbon fibers and polymer substrates,” Microelectronic Engineering, vol. 86, pp. 1250-1253, 2009.
[32] J. E. Han, D. Kim, and K. S. Yun, “All-polymer hair structure with embedded three-dimensional piezoresistive force sensors,” Sensors and Actuators A: Physical, vol. 188, pp. 89-94, 2012.
[33] M. A. Qasaimeh, S. Sokhanvar, J. Dargahi, and M. Kahrizi, “PVDF-Based Microfabricated Tactile Sensor for Minimally Invasive Surgery,” Journal of Microelectromechanical Systems, vol. 18, pp. 195-207, 2009.
[34] C. Li, P. M. Wu, S. Lee, A. Gorton, M. J. Schulz, and C. H. Ahn, “Flexible Dome and Bump Shape Piezoelectric Tactile Sensors Using PVDF-TrFE Copolymer,” Journal of Microelectromechanical Systems, vol. 17, pp. 334-341, 2008.
[35] I. S. Yang and O. K. Kwon, “A touch controller using differential sensing method for on-cell capacitive touch screen panel systems,” IEEE Transactions on Consumer Electronics, vol. 57, pp. 1027-1032, 2011.
[36] J. Rocha, P. Rocha, and S. L. Mendez, “Capacitive Sensor for Three-Axis Force Measurements and Its Readout Electronics,” IEEE Transactions on Instrumentation and Measurement, vol. 58, pp. 2830-2836, 2009.
[37] A. Shashank, M. I. Tiwana, S. J. Redmond, and N. H. Lovell, “Design, simulation and fabrication of a low cost capacitive tactile shear sensor for a robotic hand,” Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009. EMBC 2009, pp. 4132-4135, 2009.
[38] S. Y. Han, K. S. Jeon, B. Cho, M. S. Seo, J. Song, and H. S. Kong, “Characteristics of a-SiGe:H thin film transistor infrared photosensor for Touch Sensing Displays,” IEEE Journal of Quantum Electronics, vol. 48, pp. 952-959, 2012.
[39] B. Lee, I. Hong, Y. Uhm, and S. Park, “The Multi-Touch System with High Applicability using Tri-axial Coordinate Infrared LEDs,” IEEE Transactions on Consumer Electronics, vol. 55, pp. 2416-2424, 2009
[40] K. Kurita, Y. Fujii, K. Shimada, “A new technique for touch sensing based on measurement of current generated by electrostatic induction,” Sensors and Actuators A: Physical, vol. 170, pp. 66-71, 2011.
[41] J. S. X. Chen, S. Yang, S. Motojima, “Biomimetic Tactile Sensors with Fingerprint-Type Surface Made of Carbon Microcoils/Polysilicone,” Japanese Journal of Applied Physics, vol. 45, pp. L1019-L1021, 2006.
[42] S. Takenawa, “A soft three-axis tactile sensor based on electromagnetic induction,” IEEE International Conference on Mechatronics, 2009. ICM 2009, pp. 1-6, 2009.
[43] J. T. Du, W. L. Li, H. A. Xu, and Z. G. Liu, “Vibro-acoustic analysis of a rectangular cavity bounded by a flexible panel with elastically restrained edges,” The Journal of the Acoustical Society of America, vol. 131, pp. 2799-2810, 2012.
[44] M. Takasaki, Y. Fujii, H. Kotani, T. Mizuno, and T. Nara, “Proposal of Tele-touch Using Active Type SAW Tactile Display,” 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, pp. 1032-1037, 2006.
[45] H. Kotani, M. Takasaki, T. Mizuno, and T. Nara, “Integration of Tactile Information and Visual Information Using A Glass Substrate Surface Acoustic Wave Tactile Display,” SICE-ICASE, 2006. International Joint Conference, pp. 5411-5414, 2006.
[46] T. G. Zimmerman, J. R. Smith, J. A. Paradiso, D. Allport, and N. Gershenfeld, “Applying electric field sensing to human-computer interfaces,” Proceeding CHI '95 Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, pp. 280-287, 1995.
[47] T. H. Hwang, W. H. Cui, I. S. Yang, and O. K. Kwon, “A highly area-efficient controller for capacitive touch screen panel systems,” IEEE Transactions on Consumer Electronics, vol. 56, pp. 1115-1122, 2010.
[48] H. K. Lee, S. I. Chang, and E. Yoon, “Dual-mode capacitive proximity sensor for robot application: Implementation of tactile and proximity sensing capability on a single polymer platform using shared electrodes,” IEEE Sensors Journal, vol. 9, pp. 1748-1755, 2009.
[49] K. Kim, K. Shin, J. H. Han, K. R. Lee, W. H. Kim, K. B. Park, B. K. Ju and J. J. Pak, “Deformable single wall carbon nanotube electrode for transparent tactile touch screen,” Electronics Letters, vol. 47, pp. 118-120, 2011.
[50] A. Erol, G. Bebis, M. Nicolescu, R. D. Boyle, and X. Twombly, “Vision-based hand pose estimation: A review,” Computer Vision and Image Understanding, vol. 108, pp. 52-73, 2007.
[51] Y. Zhu and G. Xu, “A real-time approach to the spotting, representation, and recognition of hand gestures for human-computer interaction,” Computer Vision and Image Understanding, vol. 85, pp. 189-208, 2002.
[52] W. H. Ko, and Q. Wang, “Touch mode capacitive pressure sensors,” Sensors and Actuators A: Physical, vol. 75, pp. 242-251, 1999.
[53] S. Guo, J. Guo, and W. H. Ko, “A monolithically integrated surface micromachined touch mode capacitive pressure sensor,” Sensors and Actuators A: Physical, vol. 80, pp. 224-232, 2000.
[54] E. S. Hwang and Y. J. Kim, “A Polymer-based Flexible Tactile Sensor and Its Application to Robotics,” 2007 IEEE Sensors, pp. 784-787, 2007.
[55] D. J. Beebe, D. D. Denton, R. G. Radwin, and J. G. Webster, “A silicon-based tactile sensor for finger-mounted applications,” IEEE Transactions on Biomedical Engineering, vol. 45, pp. 151-159, 1998.
[56] M. Shikida, T. Shimizu, K. Sato, and K. Itoigawa, “Active tactile sensor for detecting contact force and hardness of an object,” Sensors and Actuators A: Physical, vol. 103, pp. 213-218, 2003.
[57] J. Engel, J Chen and C. Liu, “Development of polymide flexible tactile sensor skin,” Journal of Micromechanics and Microengineering, vol. 13, pp. 359-366, 2003.
[58] K. Kim, K. R. Lee, Y. K. Kim, D. S. Lee, N. K. Cho, W. H. Kim, K. B. Park, H. D. Park, Y. K. Park, J. H. Kim, and J. J. Pak, “3-Axes flexible tactile sensor fabricated by Si micromachining and packaging technology,” 19th IEEE International Conference on Micro Electro Mechanical Systems, 2006. MEMS 2006, pp. 22-26, 2006.
[59] E. S. Hwang, J. h. Seo, and Y. J. Kim, “A polymer-based flexible tactile sensor for both normal and shear load detections and its application for robotics,” Journal of Microelectromechanical Systems, vol. 16, pp. 556-563, 2007.
[60] U. Paschen, M. Leineweber, J. Amelung, M. Schmidt, and G. Zimmer, “A novel tactile sensor system for heavy-load applications based on an integrated capacitive pressure sensor,” Sensor and Actuators A, Physical, vol. 68, pp. 294-298, 1998.
[61] I. H. Shan, T. Mei, L. Sun, D. Y. Kong, Z. Y. Zhang, L. Ni, M. Meng, and J. R. Chu, “The design and fabrication of a flexible three-dimensional force sensor skin,” 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2005, pp. 1818-1823, 2005.
[62] H. K. Lee, S. I. Chang, K. H. Kim, S. J. Kim, K. S. Yun, and E. Yoon, “A modular expandable tactile sensor using flexible polymer,” 18th IEEE International Conference on Micro Electro Mechanical Systems, 2005. MEMS 2005, pp. 642-645, 2005.
[63] H. K. Lee, S. I. Chang, and E. Yoon, “A flexible polymer tactile sensor: fabrication and modular expandability for large area deployment,” Journal of Microelectromechanical Systems, vol. 15, pp. 1681-1686, 2006.
[64] C. T. Chuang, and R. Chen, “Micro capacitive tactile sensor for contact loads,” Advanced materials research, vol. 33, pp. 931-936, 2008.
[65] C. T. Chuang, and R. Chen, “Design, fabrication, and characterization of out-of-plane W-form microsprings for vertical comb electrodes capacitive sensor,” Journal of Micro/Nanolithography, MEMS, and MOEMS, vol. 8, pp. 033021, 2009.
[66] C. T. Chuang, C. K. Chan, and R. Chen, “Micro three-axial capacitive touch force sensor using MOSBE Ⅱ”, 22th International Microprocesses and Nanotechnology Conference, pp. 86-87, 2009.
[67] M. Y. Cheng, X. H. Huang, C. W. Ma, and Y. J. Yang, “A flexible capacitive tactile sensing array with floating electrodes,” Journal of Micromechanics and Microengineering, vol. 19, 2009.
[68] M. Y. Cheng, B. T. Liao, X. H. Huang, and Y. J. Yang, “A flexible tactile sensing array based on novel capacitance mechanism,” 15th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS 2009, pp. 2182-2185, 2009.
[69] P. Peng, R. Rajamani, and A. G. Erdman, “Flexible Tactile Sensor for Tissue Elasticity Measurements,” Journal of Microelectromechanical Systems, vol. 18, pp. 1226-1233, 2009.
[70] H. K. Lee, S. I. Chang, and E. Yoon, “Dual-Mode capacitive proximity sensor for robot application: implementation of tactile and proximity sensing capability on a single polymer platform using shared electrodes,” IEEE Sensors Journal, vol. 9, pp. 1748-1755, 2009.
[71] H. K. Lee, S. I. Chang, and E. Yoon, “A capacitive proximity sensor in dual implementation with tactile imaging capability on a single flexible platform for robot assistant applications,” 19th IEEE International Conference on Micro Electro Mechanical Systems, 2006. MEMS 2006, pp. 606-609, 2006.
[72] H. K. Lee, J. Chung, S. I. Chang, and E. Yoon, “Normal and shear force measurement using a flexible polymer tactile sensor with embedded multiple capacitors,” Journal of Microelectromechanical Systems, vol. 17, pp. 934-942, 2008.
[73] M. Y. Cheng, C. L. Lin, and Y. J. Yang, “Tactile and shear stress sensing array using capacitive mechanism with floating electrodes,” 23th IEEE International Conference on Micro Electro Mechanical Systems, 2010. MEMS 2010, pp. 228-231, 2010
[74] M. Y. Cheng, C. M. Tsao, Y. Z. Lai, Y. J. Yang, “The development of a highly twistable tactile sensing array with stretchable helical electrodes,” Sensors and Actuators A: Physical, vol. 166, pp. 226-233, 2011.
[75] H. K. Kim, S. G. Lee, J. E. Han, T. R. Kim, S. U. Hwang, S. D. Ahn, I. K. You, K. I. Cho, T. K. Song, and K. S. Yun, “Transparent and flexible tactile sensor for multi touch application with force sensing,” 15th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS 2009. pp. 1146-1149, 2009.
[76] Y. C. Wang, T. Y. Chen, R. Chen, and C. Y. Lo, “Mutual Capacitive Flexible Tactile Sensor for 3D Image Control,” Journal of Microelectromechanical Systems, vol. 22, pp. 804-814, 2013.
[77] 王詠辰，“可檢測正向力和剪力之透明軟性觸覺感測器系統”，國立清華大學動力機械工程學系碩士論文，民國一百年
[78] Y. F. Lan, W. C. Peng, Y. H. Lo, and J. L. He, “Durability under mechanical bending of the indium tin oxide films deposited on polymer substrate by thermionically enhanced sputtering,” Organic Electronics, vol. 11, pp. 670-676, 2010.
[79] Y. S. Kim, W. J. Eun, K. T. Choa, and S. Hoon, “Mechanical reliability of transparent conducting IZTO film electrodes for flexible panel displays,” Applied Surface Science, vol. 257, pp. 8134-8138, 2011.
[80] S. H. Choa, C. K. Cho, W. J. Hwang, K. T. Eun, and H. K. Kim, “Mechanical integrity of flexible InZnO/Ag/InZnO multilayer electrodes grown by continuous roll-to-roll sputtering,” Solar Energy Materials and Solar Cells, vol. 95, pp. 3442-3449, 2011.
[81] J. A. Dobrzynska, and M. A. Gijs, “Flexible polyimide-based force sensor,” Sensors and Actuators A: Physical, vol. 173, pp. 127-135, 2012.
[82] 郭俊頡，“利用RF濺鍍技術於室溫下將ITO成長在塑膠基板上之研究”，國立中山大學光電工程所碩士論文，民國九十四年。
[83] Y. K. Su, S. J. Chang, C. H. Chen, J. F. Chen, G. C. Chi, J. K. Sheu, W. C. Lai, and J. M. Tsai, “GaN metal-semiconductor-metal ultraviolet sensors with various contact electrodes,” IEEE Sensors Journal, vol. 2, pp. 366-371, 2002.
[84] S. I. Park, J. H. Ahn, X. Feng, S. Wang, Y. Huang, and J. A. Rogers, “Theoretical and Experimental Studies of Bending of Inorganic Electronic Materials on Plastic Substrates,” Advanced Functional Materials, vol. 18, pp. 2673-2684, 2008.
[85] 簡于涵，“於曲面下操作之軟性觸覺感測器特性分析”，國立清華大學動力機械工程學系碩士論文，民國一○一年。
[86] 鍾易宸，“利用偏移電容式觸覺感測器陣列量測具角度之側向力”，國立清華大學動力機械工程學系碩士論文，民國一○二年。
[87] J. N. Reddy, “Theory and Analysis of Elastic Plates and Shells,” Boca Raton: CRC Press, pp. 430-441, 2007.