THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. 2014 Jan.; 25(1), 47 52. http://dx.doi.org/10.5515/kjkiees.2014.25.1.47 ISSN 1226-3133 (Print) ISSN 2288-226X (Online) Circuit Modeling and Analysis of Touch Screen Panel 변기식 민병욱 Kisik Byun Byung-Wook Min 요약,. 2D EM circuit, 23 5 RC. EM/circuit 5 RC S, 5 130 khz 10. 7 RC 10 200 khz. Abstract A simple RC circuit model of large-scale touch screen panels is developed and the frequency range of the RC model is analyzed. 2D EM simulation results of a single touch cell are cascaded for a 23 inch touch panel using a circuit simulator, and the shortest and longest channels of the full panel are modeled with a 5-element RC circuit. The 5-element RC circuit can model the touch screen panel upto 130 khz with the channel phase error of 10. 7-element RC circuit model is also proposed and the frequency range for the channel phase error of 10 is extended to 200 khz. Key words: Capacitive Touch Screen, RC Circuit Model. 서론,,,.,. [1],[2]., [3],[4]. EM/circuit 23 RC, RC [5]. 23 5 RC. (Department of Electrical and Electronic Engineering, Yonsei University) Manuscript received August 23, 2013 ; Revised October 30, 2013 ; Accepted December 12, 2013. (ID No. 20130823-12S) Corresponding Author: Byung-Wook Min (e-mail: bmin@yonsei.ac.kr) c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved. 47
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 1, Jan. 2014., 7 RC,.. 터치패널과 5소자 RC 모델링 1 stack-up (Case,, ). Case GFF Glass- - 2. Case G1F Glass-, [6]. OCA(Optically Clear Adhesive) 5.12 [7], 3.28 PET. PET ITO(Indium Tin Oxide) metal mesh. ITO, 150 Ω/o. 20 metal mesh ITO. Metal mesh metal,. 1 metal mesh. mesh metal, pitch metal, mesh. 표 1. Metal mesh Table 1. Characteristics of metal mesh. Metal mesh type (um) Pitch (um) (Ω/o) mesh A 0.2 270 100 mesh B 12.0 270 0.01 2 23. TX driver, RX receiver. TX driver RX receiver, TX driver.., 20 EM., RX TX EM., (=TX RX ). 2(b), EM 그림 1. stack-up Fig. 1. Stack-up of touch screen panel. 48
그림 2. (a) 23 (b) (c) TX-RX Fig. 2. (a) 23 inch touch screen panel, (b) model of the single touch cell and (c) model of TX-RX channel., TX RX (Rcell_tx, Rcell_rx), (Ccell_tx, Ccell_ rx), (Ccell_mutual). Stack-up (Case I,, ) 2D EM 2., Shortest Longest, R. C curve fitting., driver, receiver Ground. EM TX driver RX receiver TX-RX circuit 2(c) 5 RC. TX-RX 표 2. Stack-up, metal mesh, gap RC Table 2. Single cell RC modeling parameters according to stack-up, metal mesh and gap material. Stack-up TX, RX Layer RX : mesh B TX : mesh B Rcell_tx Rcell_rx Ccell_tx (ff) Ccell_rx (ff) Ccell_mutual 85 11.5 10 3 10 10 3.4 6.3 10 3 116 10 10 6.8 85 116 10 10 5.4 49
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 1, Jan. 2014. S21 magnitude (db) -60-70 -80-90 0 RC model -100 23-inch panel (EM/Circuit sim.) -20 0 50 100 150 200 Frequency (khz) Shortest Longest 100 그림 3. TX-RX 5 S Fig. 3. S-parameters of TX-RX channels and 5-element RC circuit model. (shortest and longest path),. 3 case EM/ circuit 5 RC S. 5 TX-RX. 5 RC, 130 khz 10 S 21. -. on/off, 80 60 40 20 S21 phase (degree) sample, hold, transfer,.,. 130 khz 10 0.21 us [8]. TX-RX, 10. Stack-up (Case I,, ) TX-RX RC 3. Metal mesh B 0.01 Ω/o, Case I RX (R_rx) Case TX (R_tx). TX-RX (R_tx, R_rx),., path (Cself), longest (Cself) shortest. layer conductivity, (Cself) longest path shortest path., [9]., 표 3. Stack-up RC Table 3. Touch screen panel RC modeling parameters according to stack-up and channel length. Stack-Up TX, RX Layer RX : mesh B TX : mesh B TX-RX R_tx R_rx Cself_tx Cself_rx Cmutual Longest 7,730 1.90 240 110 3.6 Shortest 85 12.3 10 3 240 60 3.5 Longest 0.57 18,000 100 92 7.2 Shortest 6.3 10 3 116 63 92 7.2 Longest 7,240 18,000 81 210 5.4 Shortest 85 116 48 210 5.4 50
. 20 %. Minimum detectable Cmutual/Cself_rx 100. minimum detectable 0.51 %., (Cmutual) TX-RX (Cself_ tx, Cself_tx).. 주파수영역확장 7소자모델. 5 RC 130 khz., 7 RC. 4 23 RC. 5 RX, TX 1 1, 7 RX, TX 2 1. 5,, (R_rx =0.5 R_rx).,. 5 23 EM/circuit, 7 RC 5 S. 200 khz Longest 7 RC 5 RC, 15. 7 RC, 10 S21 magnitude (db) -60-70 -80-90 7-element RC model -20 23-inch panel (EM/Circuit sim.) -100 5-element RC model -40 0 50 100 150 200 250 300 Frequency (khz) Shortest Longest 100 그림 5. TX-RX 7 S Fig. 5. S-parameters of TX-RX channels and 7-element RC circuit model. S 21 200 khz.. 결론 2D EM circuit, 23 TX-RX 5 RC., 5 RC 130 khz 10 S 21., 7 RC 10 S 21 200 khz.. 80 60 40 20 0 S21 phase (degree) References 그림 4. TX-RX 7 RC Fig. 4. 7-element RC circuit model for TX-RX channels. [1], " (TSP) ",, 1577, pp. 1-11, 2012 12. [2] Mudit Ratana Bhalla, Anad Vardhan Bhalla, "Compa- 51
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 1, Jan. 2014. 정우석, "윈도우 일체형 대면적 터치스크린 패널", 전 기전자재료, 25(12), pp. 21-27, 2012년 12월. [7] 박은숙, 박지원, 김현중, "디스플레이용 점 접착 소 재", Polymer Science and Technology, vol. 23, no, 1, pp. rative study of various touchscreen technologies", International Journal of Computer Applications, vol. 6, no. 8, pp. 12-18, 2010. [3] Jun-Hyeok Yang, et al., "A highly noise-immune touch controller using filtered-delta-integration and a charge_interpolation technique for 10.1-inch capacitive touch-screen panels", Solid-State Circuits Conference Digest of Technical Papers(ISSCC), 2013 IEEE International, pp. 390-391, 2013. [4] Gary Barrett, Ryomei Omote, "Projected-c apacitive touch technology", Information Display, 3/10, pp. 16-21, 2010. [5],, "23 ", 2013, 1(1), pp. 201, 2013 8. [6] 변기 식 민병 욱 변기식 민병욱 인치 터치스크린 패널의 회로 모 델링 및 분석 한국전자파학회 하계종합학술대 회 년월 년 2월: 한양대학교 전자통신컴퓨터 공학부 (공학사) 2013년 3월 현재: 연세대학교 전기전자 공학과 석사과정 [주 관심분야] 마이크로파 회로, Graphene 2013 Device 52 47-60, 2012. [8] Hyungcheol Shin, Seunghoon Ko, Hongjae Jang, Ilhyun Yun, and Kwyro Lee, "A 55 db SNR with 240 Hz frame scan rate mutual capacitor 30 24 touch-screen panel readout IC using code-division multiple sensing technique", Solid-State Circuits Conference Digest of Technical Papers(ISSCC), 2013 IEEE International, pp. 388-389, 2013. [9]," ", 2013 2. 정도영 대면적 정전식 터치스크린 패널을 위한 고성 능 터치 검출회로 설계 연세대학교 대학원 전기전자 공학과 년 월 년 8월: 서울대학교 전기공학부 (공학 사 년 8월: 미국 University of Michigan, Arbor (공학석사) 년 4월: 미국 University of Michigan, Arbor (공학박사) 년 1월 2010년 12월: Qualcomm Inc. Senior Engineer 2011년 9월 현재: 연세대학교 전기전자공학부 조교수 [주 관심분야] 밀리미터파 집적회로, 마이크로파 회로, 위상배 열 안테나시스템, Analog/RF IC 2002 ) 2004 Ann 2008 Ann 2008