Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Characteristics of Flexible Transparent Capacitive Pressure Sensor Using Silver Nanowire/PEDOT:PSS Hybrid Film

은나노와이어·전도성고분자 하이브리드 필름을 이용한 유연 투명 정전용량형 압력 센서의 특성

  • Ahn, Young Seok (Graduate School of NID Fusion Technology, Seoul National University of Science and Technology) ;
  • Kim, Wonhyo (Smart Sensor Research Center, Korea Electronics Technology Institute) ;
  • Oh, Haekwan (Smart Sensor Research Center, Korea Electronics Technology Institute) ;
  • Park, Kwangbum (Smart Sensor Research Center, Korea Electronics Technology Institute) ;
  • Kim, Kunnyun (Smart Sensor Research Center, Korea Electronics Technology Institute) ;
  • Choa, Sung-Hoon (Graduate School of NID Fusion Technology, Seoul National University of Science and Technology)
  • 안영석 (서울과학기술대학교 나노IT디자인 융합기술대학원) ;
  • 김원효 (전자부품연구원 스마트센서 연구센터) ;
  • 오해관 (전자부품연구원 스마트센서 연구센터) ;
  • 박광범 (전자부품연구원 스마트센서 연구센터) ;
  • 김건년 (전자부품연구원 스마트센서 연구센터) ;
  • 좌성훈 (서울과학기술대학교 나노IT디자인 융합기술대학원)
  • Received : 2016.08.02
  • Accepted : 2016.09.27
  • Published : 2016.09.30
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Abstract

In this paper, we developed a flexible transparent capacitive pressure sensor which can recognize X and Y coordinates and the size of force simultaneously by sensing a change in electrical capacitance. The flexible transparent capacitive pressure sensor was composed of 3 layers which were top electrode, pressure sensing layer, and bottom electrode. Silver nanowire(Ag NW)/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hybrid film was used for top and bottom flexible transparent electrode. The fabricated capacitive pressure sensor had a total size of 5 inch, and was composed of 11 driving line and 19 sensing line channels. The electrical, optical properties of the Ag NW/PEDOT:PSS and capacitive pressure sensor were investigated respectively. The mechanical flexibility was also investigated by bending tests. Ag NW/PEDOT:PSS exhibited the sheet resistance of $44.1{\Omega}/square$, transmittance of 91.1%, and haze of 1.35%. Notably, the Ag NW/PEDOT:PSS hybrid electrode had a constant resistance change within a bending radius of 3 mm. The bending fatigue tests showed that the Ag NW/PEDOT:PSS could withstand 200,000 bending cycles which indicated the superior flexibility and durability of the hybrid electrode. The flexible transparent capacitive pressure sensor showed the transmittance of 84.1%, and haze of 3.56%. When the capacitive pressure sensor was pressed with the multiple 2 mm-diameter tips, it can well detect the force depending on the applied pressure. This indicated that the capacitive pressure sensor is a promising scheme for next generation flexible transparent touch screens which can provide multi-tasking capabilities through simultaneous multi-touch and multi-force sensing.

본 연구에서는 유연하고 투명한 특성을 지닌 유연 투명 정전용량형 압력 센서를 제안하여 기존의 X, Y 좌표 위치 인식이 가능할 뿐만 아니라 3차원 인식이 가능한 터치스크린을 제작하였다. 유연 투명 정전용량형 압력 센서는 상부 기판, 압력 감지층, 하부 기판의 3 중 구조로 구성되어 있다. 은나노와이어 전도성고분자 하이브리드 필름이 상부 및 하부 기판으로 사용되었다. 유연 투명 정전용량형 압력 센서의 터치 면적은 5인치이며, 전기적 신호를 인가하기 위한 11개의 driving line과 정전용량의 변화를 감지하기 위한 19개의 sensing line으로 구성되었다. 은나노와이어 전도성고분자 하이브리드 필름 및 유연 투명 정전용량형 압력 센서의 전기적, 광학적 특성을 평가하였다. 또한 기계적 유연성을 평가하기 위하여 굽힘 시험을 수행하였다. 제작된 은나노와이어 전도성고분자 하이브리드 필름은 평균 투과율 91.1%, 평균 탁도 1.35%로서 매우 우수한 광학 특성을 나타내었고, 평균 면저항은 $44.1{\Omega}/square$이었다. 굽힘 시험 결과 은나노와이어 전도성고분자 필름은 곡률 반경 3 mm까지 저항의 변화가 거의 없어 매우 우수한 유연성을 갖고 있음을 알 수 있었다. 또한 200,000회의 반복 굽힘 피로 시험 결과, 저항의 증가는 매우 미미하여, 유연 내구성이 매우 우수함을 알 수 있었다. 유연 투명 정전용량형 압력 센서의 평균 투과율은 84.1%, 탁도는 3.56%이었다. 또한, 직경 2 mm의 팁으로 눌렀을 경우, 누르는 압력에 따라 센서가 잘 작동함을 알 수 있었으며, 이를 통하여 멀티 터치 및 멀티 포스 터치가 가능함을 확인하였다. 본 연구에서 제작한 유연 투명 정전용량형 압력 센서는 유저인터페이스, 사용자 경험이 강조되고 있는 현재 상황에서 새로운 인터페이스의 터치스크린 패널에 대한 발전 가능성을 제시할 수 있을 것이라 판단된다.

Keywords

References

  1. G. Walker, "Fundamentals of Touch Technologies and Applications", Society for Information Display (2011).
  2. C. Villamor, D. Willis and L. Wroblewski, "Touch gesture reference guide", Touch Gesture Reference Guide (2010).
  3. H. Ohta, M. Orita, M. Hirano, H. Tanji, H. Kawazoe and H. Hosono, "Highly electrically conductive indium-tin-oxide thin films epitaxially grown on yttria-stabilized zirconia (100) by pulsed-laser deposition", Applied Physics Letters, 76(19), 2740 (2000). https://doi.org/10.1063/1.126461
  4. R. B. H. Tahar, T. Ban, Y. Ohya and Y. Takahashi, "Tin doped indium oxide thin films: Electrical properties", Journal of Applied Physics, 83(5), 2631 (1998). https://doi.org/10.1063/1.367025
  5. K. A. Sierros, N. J. Morris, K. Ramji and D. R. Caims, "Stresscorrosion cracking of indium tin oxide coated polyethylene terephthalate for flexible optoelectronic devices", Thin Solid Films, 517(8), 2590 (2009). https://doi.org/10.1016/j.tsf.2008.10.031
  6. J.-H. Kim, M.-W. Chon and S.-H. Choa, "Technology of Flexible Transparent Conductive Electrode for Flexible Electronic Devices", J. Microelectron. Packag. Soc., 21(2), 1 (2014).
  7. D. S. Hecht, D. Thomas, L. Hu, C. Ladous, T. Lam, Y. Park and P. Drzaic, "Carbon-nanotube film on plastic as transparent electrode for resistive touch screens", Journal of the Society for Information Display, 17(11), 941 (2009). https://doi.org/10.1889/JSID17.11.941
  8. K. S. Kim, Y. Zhao, H. Jang, S. Y. Lee, J. M. Kim, K. J. H. Ahn, P. Kim, J. Y. Choi and B. H. Hong, "Large-scale pattern growth of graphene films for stretchable transparent electrodes", Nature, 457(7230), 706 (2009). https://doi.org/10.1038/nature07719
  9. D.-G. Kim, Y. Kim and J.-W. Kim, "Recent Trends in Development of Ag Nanowire-based Transparent Electrodes for Flexible.Stretchable Electronics", J. Microelectron. Packag. Soc., 22(1), 7 (2015). https://doi.org/10.6117/kmeps.2015.22.1.007
  10. J. Park, J. Lee and Y. Y. Noh, "Optical and thermal properties of large-area OLED lightings with metallic grids", Organic Electronics, 13(1), 184-194 (2012). https://doi.org/10.1016/j.orgel.2011.10.024
  11. S.-I. Na, S.-S. Kim, J. J. and D.-Y. Kim, "Efficient and Flexible ITO-Free Organic Solar Cells Using Highly Conductive Polymer Anodes", Advanced Materials, 20(21), 4061 (2008). https://doi.org/10.1002/adma.200800338
  12. J. Elwell, "P-200L: Late-News Poster: Sensing Touch by Sensing Force", SID Symposium Digest of Technical Papers, 38(1), 312 (2007).
  13. S. Heo and G. Lee "Force gestures: augmenting touch screen gestures with normal and tangential forces", Proceedings of the 24th annual ACM symposium on User interface software and technology, 621 (2011).
  14. C.-L. Lin, C.-S. Li, Y.-M. Chang, C.-C. Hung and A. Lin, "3D stylus and pressure sensing system for capacitive touch panel", 2012 IEEE International Conference on Consumer Electronics (ICCE), 215 (2012).
  15. T.-Y. Chen, Y.-C. Wang, C.-Y. Lo and R. Chen, "A novel integrated transparent flexible tactile sensor", 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, 1052 (2011).
  16. H. Lee, J. Chung, S. Chang and E. Yoon, "Normal and shear force measurement using a flexible polymer tactile sensor with embedded multiple capacitors", J. Microelectron. Packag. Soc., 17(4), 934 (2008).
  17. H.-K. Kim, S. Lee and K.-S. Yun, "Capacitive tactile sensor array for touch screen application", Sensors and Actuators A: Physical, 165(1), 2 (2011). https://doi.org/10.1016/j.sna.2009.12.031
  18. B. Zhang, Z. Xiang, S. Zhu, Q. Hu, Y. Cao, J. Zhong, Q. Zhong, B. Wang, Y. Fang, B. Hu, J. Zhou and Z. Wang, "Dual functional transparent film for proximity and pressure sensing", Nano Research, 7(10), 1488 (2014). https://doi.org/10.1007/s12274-014-0510-3
  19. W. Kim, H. Oh, Y. Kwak, K. Park, B.-K. Ju and K. Kim, "Development of a carbon nanotube-based touchscreen capable of multi-touch and multi-force sensing", Sensors, 15(11), 28732 (2015). https://doi.org/10.3390/s151128732
  20. S. Kim, S. Y. Kim, J. Kim and J. H. Kim, "Highly reliable AgNW/PEDOT: PSS hybrid films: efficient methods for enhancing transparency and lowering resistance and haziness", Journal of Materials Chemistry C, 2(28), 5636 (2014). https://doi.org/10.1039/c4tc00686k
  21. S.-I Park, J.-H. Ahn, S. Wang, Y. G. Huang and J. A. Rogers, "Theoretical and Experimental Studies of Bending of Inorganic Electronic Materials on Plastic Substrates", Advanced Functional Materials, 18(18), 2673 (2008). https://doi.org/10.1002/adfm.200800306
  22. W. A. MacDonald, "Engineered films for display technologies", Journal of Materials Chemistry, 14(1), 4 (2004). https://doi.org/10.1039/b310846p

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