近年來，閘極驅動電路整合於玻璃基板被廣泛的使用在主動式矩陣液晶顯示器和主動式矩陣有機發光二極體中由於高可靠性及透過減少額外驅動積體電路而降低成本。此外氫化非晶矽薄膜電晶體製程和低溫多晶矽薄膜電晶體製程為目前顯示器之主流，其中，氫化非晶矽薄膜電晶體製程具有簡單且高良率和高均勻度之優點，然而長時間操作會導致臨界電壓飄移之特性為電路設計之重點，在許多觸控技術中，內嵌式觸控技術大量的使用於液晶顯示器中，因為內嵌式觸控技術能擁有較輕薄的外觀，然而由於將觸控元件整合於液晶中，觸控訊號易發生顯示器至觸控串擾現象(DTX)，一般的解決方式為將觸控感測與顯示器動作分開，因此當觸控感測時，顯示器會停止動作導致驅動薄膜電晶體長時間偏壓之問題。此外觸控回報率將受限於顯示器幀數而導致觸控品質下降。本論文提出一個使用氫化非晶矽薄膜電晶體為內嵌式觸控面板所設計之驅動電路，由十一顆薄膜電晶體與三顆電容所組成，此電路利用預充電架構來避免電路之驅動薄膜電晶體在觸控感測階段受到長時間偏壓影響，導致嚴重的臨界電壓飄移。由模擬結果顯示，輸出波形之上升與下降時間在觸控感測階段後分別為2.73 µs與1.92 µs證明此電路應用於內嵌式觸控面板之可行性。
高解析度與高畫面更新頻率為目前顯示器發展之趨勢，低溫多晶矽薄膜電晶體具有高驅動能力與高穩定性之特性而被廣泛的使用於主動式矩陣有機發光二極體顯示器，然而臨界電壓變異與高漏電流之特性為設計重點。而傳統畫素電路資料寫入階段與補償階段結合在一起，因此當解析度及畫面更新頻率上升時，顯示器每列所分得操作時間縮短，勢必面臨補償時間不足之問題，為應用於高解析度顯示器，本論文提出平行補償架構之畫素電路與為同步式發光驅動法所設計之閘極驅動電路，其中畫素電路由七顆薄膜電晶體與三個電容所組成之兩相鄰畫素電路，藉由對稱架構來對相鄰兩畫素補償臨界電壓變異，因此可以簡化電路所需元件數，此外透過調整ELVDD可以避免閃爍現象發生。由模擬結果顯示，電流相對錯誤率在資料電壓範圍內皆可維持在5%以下，證明此電路應用於高解析度顯示器之可行性。另外，閘極驅動電路為同步式發光驅動法所設計，由十顆薄膜電晶體與兩個電容所組成，所提出電路可以產生同步式發光驅動法所需之輸出波形，在補償階段時利用SS2訊號改變在每個列產生相同輸出波形，並於資料寫入階段，產生漸進式輸出波形，根據模擬結果，所提出電路產生輸出波形之下降時間與上升時間在補償階段為0.53 µs與0.53 µs，而在資料寫入階段則為0.54 µs與0.58 µs，證明此電路應用於高解析度同步式發光驅動法面板之可行性。

In recent year, integrated gate driver circuit on glass substrate is widely used in active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diode (AMOLED) owing to its high reliability, and low cost by eliminating external integrated circuits (ICs). Moreover, hydrogenated amorphous silicon (a-Si:H) and low-temperature poly-silicon (LTPS) thin film transistors (TFTs) become mainstream in current displays. First, a-Si:H TFTs have many advantages including simple fabrication, high yield and high uniformity. However, the threshold voltage (VTH) shift under long-term operation is the important issue for the circuit design. Among many touch technologies, in-cell touch technologies are applied to AMLCDs for thinner and lighter devices. Nevertheless, the touch components are integrated in the LCD cells, resulting in display to touch crosstalk (DTX). To resolving this phenomenon, the display operation is separated from touch sensing. Thus, the driving TFTs are under long-term stress when the display stops operation in touch sensing period. In addition, the frame rate of display restricts touch reporting rates, leading to the reduction of touch quality. This thesis proposes a gate driver circuit based on a-Si:H TFTs for in-cell touch panel. The proposed circuit contains eleven TFTs and three capacitors. By pre-charged structure, the driving TFT can avoid under long-term stress to improve the severe VTH shift in touch sensing period. According to simulation results, the rising and falling times of output waveforms are respectively 2.73 µs and 1.92 µs, ensuring the feasibility of proposed circuit to realize on an in-cell touch panel.
The high-resolution and high-frame rate displays are the current trend. Due to high driving capability and high stability, LTPS TFTs are extensively used for AMOLED displays. However, the VTH variations and high leakage current are important issues for the circuit design. When the resolution and frame rate of display increases, the scanning time reduces for each row. The previously proposed pixel circuits use the data line to provide the reference voltage for compensation and data voltage for data input, so the compensation time is restricted by shorten scanning time. This issue results in poor image quality in high-resolution displays. Thus, the thesis proposes a pixel circuit with parallel driving scheme and a gate driver circuit for simultaneous emission (SE) driving method for high-resolution displays. A pixel circuit consists of seven TFTs and three capacitors in two adjacent pixels. The VTH variations are compensated by symmetrical structure in two pixels, so the numbers of components are reduced. Moreover, the ELVDD signal is used to avoid flicker phenomenon. As shown in simulation results, the relative current error rates are lower than 5% over all range of data voltage, verifying the functionality of proposed pixel circuit. Also, the gate driver circuit for SE driving method is composed of ten TFTs and two capacitors. In compensation period, the SS2 signal is used to generate the identical waveforms for each row. In data input period, the circuit can generate progressive output waveforms. Simulation results demonstrate that the falling and rising times are respectively 0.53 µs and 0.53 µs in compensation period and 0.54 µs and 0.58 µs in data input period, ensuring the feasibility of proposed circuit to realize a high-resolution panel with SE driving method.

[1] U. B. Kang and Y. H. Kim, “A new COG technique using low temperature solder bumps for LCD driver IC packaging applications,” IEEE Trans. Compon. Packag. Technol., vol. 27, no. 2, pp. 253-258, Jan. 2004.
[2] H. Kristiansen and J. Liu, “Overview of conductive adhesive interconnection technologies for LCDs,” IEEE Trans. Comp., Packag., Manuf. Technol. A, vol. 21, no. 2, pp. 208-214, Jan. 1998.
[3] Y. H. Tai, “Design and operation of TFT-LCD panels,” Wunan, 2006.
[4] J. W. Choi, J. I. Kim, S. H. Kim, and J. Jang, “Low-power a-Si:H gate driver circuit with threshold-voltage-shift recovery and synchronously controlled pull-down scheme,” IEEE Trans. Electron Devices, vol. 62, no. 1, pp. 136-142, Jan. 2015.
[5] Z. Hu, C. Liao, W. Li, L. Zeng, C. Y. Lee, and S. Zhang, “Integrated aSi:H gate driver with low-level holding TFTs biased under bipolar pulses,” IEEE Trans. Electron Devices, vol. 62, no. 12, pp. 4044-4050, Dec. 2015.
[6] J. H. Yang, S. C. Jung, Y. S. Son, S. T. Ryu, and G. H. Cho, “A noise-immune high-speed readout circuit for in-cell touch screen panels,” IEEE Trans.Circuits Syst. I, Reg. Papers, vol. 60, no. 7, pp. 1800-1809, Jul. 2013.
[7] Y. Teranishi, K. Noguchi, H. Mizuhashi, K. Ishizaki, H. Kurasawa, and Y. Nakajima, “New in-cell capacitive touch panel technology with low resistance material sensor and new driving method for narrow dead band display,” in SID Symp. Dig., 2016, pp. 502-505.
[8] C. H. Chiang, Y. E. Wu, K. T. Ho, and P. Y. Chan, “Mutual-capacitance in-cell touch panel,” in SID Symp. Dig., 2016, pp. 498-501.
[9] M. Kimura, I. Yudasaka, S. Kanbe, H. Kobayashi, H. Kiguchi, S. I. Seki, S. Miyashita, T. Shimoda, T. Ozawa, K. Kitawada, T. Nakazawa, W. Miyazawa, and H. Ohshima, “Low-temperature polysilicon thin-film transistor driving with integrated driver for high-resolution light emitting polymer display,” IEEE Trans. Electron Devices, vol. 46, no. 12, pp. 2282-2288, Dec. 1999.
[10] B. T. Chen, Y. J. Kuo, C. C. Pai, C. C. Tsai, H. C. Cheng, and Y. H. Tai, “A new pixel circuit for driving organic light emitting diodes with low temperature polycrystalline thin film transistors,” in Proc. Int. Display Manuf. Conf., 2005, pp. 378-381.
[11] A. Nathan, G. R. Chaji, and S. J. Ashtiani, “Driving scheme for a-Si and LTPS AMOLED displays,” IEEE/OSA Journal of Display Technology, vol. 1, no. 2, pp. 267-277, Dec. 2005.
[12] S. H. Moon, Y. S. Lee, M. C. Lee, B. H. Berkeley, N. D. Kim, and S. S. Kim, “Integrated a-Si:H TFT gate driver circuits on large area TFT-LCDs,” in SID Symp. Dig., 2007, pp. 1478-1481.
[13] M. Nakamizo, M. Yonemaru, Y. Iwase, and T. Fukaya, “A low power consumption and high reliability architecture for a-Si TFT gate driver on glass,” in SID Symp. Dig., May 2010, vol. 41. no. 1, pp. 28-31.
[14] C. Liao, Z. Hu, D. Dai, S. Chung, T. S. Jen, and S. Zhang, “A compact bi-direction scannable a-Si:H TFT gate driver,” J. Display Technol., vol. 11, no. 1, pp. 3-5, Jan. 2015.
[15] R. Dawson, Z. Shen, D. Furst, S. Connor, J. Hsu, M. Kane, et al., “Design of an improved pixel for a polysilicon active-matrix organic LED display,” in SID Symp. Dig., 1998, pp. 11-14.
[16] M. Stewart, R. S. Howell, L. Pires, and M. K. Hatalis, “Polysilicon TFT technology for active matrix OLED displays,” IEEE Trans. Electron Devices, vol. 48, no. 5, pp. 845-851, May 2001.
[17] H. J. In, K. H. Oh, I. Lee, D. H. Ryu, S. M. Choi, K. N. Kim, H. D. Kim, and O. K. Kwon, “An advanced external compensation system for active matrix organic light-emitting diode displays with poly-Si thin-film transistor backplane,” IEEE Trans. Electron Devices, vol. 57, no. 11, pp. 3012-3019, Nov. 2010.
[18] D. A. Stronks, A. Al-Dahle, and W. H. Yao, “Devices and methods for reduction of display to touch crosstalk,” U.S. Patent. 0 084 911, 2015.
[19] S. H. Moon, I. Haruhisa, K. Kim, C. W. Park, H. J. Chung, S. H. Kim, B. K. Kim, and O. Kim, “Highly robust integrated gate-driver for in-cell touch TFT-LCD driven in time division driving method, ” IEEE/OSA Journal of Display Technology, vol. 12, no. 5, May 2016.
[20] G. R. Chaji and A. Nathan, “Parallel addressing scheme for voltage programmed active-matrix OLED displays,” IEEE Trans. Electron Devices, vol. 54, no. 5, pp. 1095-1100, May 2007.
[21] K. H. Chung, B. Y. Chung, S. I. Park, D. W. Park, S. M. Choi, K. Kim, B. H. Kim, and S. S. Kim, “Integrated pMOS gate driver for a 3D AMOLED display,” in Proc. SID Tech. Dig., 2011, pp.349-352.
[22] C. L. Lin, C. E. Wu, C. E. Lee, F. H. Chen, P. S. Chen, and M. X. Wang, “Insertion of simple structure between gate driver circuits to prevent stress degradation in in-cell touch panel using multi-V blanking method, ” IEEE/OSA Journal of Display Technology, vol. 12, no. 10, pp. 1040-1042, Oct. 2016.
[23] C. L. Lin, M. Y. Deng, C. E. Wu, P. S. Chen, and M. X. Wang, “gate driver circuit using pre-charge structure and time-division multiplexing driving scheme for active-matrix LCDs integrated with in-cell touch structures,” IEEE/OSA Journal of Display Technology, vol. 12, no. 11, pp. 1238-1241, Nov. 2016.
[24] Chih-Lung Lin*, Chun-Da Tu, Min-Chin Chuang, and Jian-Shen Yu, “design of bidirectional and highly stable integrated hydrogenated amorphous silicon gate driver circuits,” IEEE/OSA Journal of Display Technology, vol. 7, no. 1, pp. 10-18, Jan. 2011.
[25] M. D. Chun, S. Y. Yoon, Y. H. Jang, K. S. Park, H. Y. Kim, B. Kim, H. N. Cho, S. C. Choi, T. W. Moon, N. W. Cho, S. H. Jo, C. Y. Sohn, C. D. Kim, and I. J. Chung, “Bi-directional integrated a-Si gate driver circuit for LCD panel with RGBW quad subpixels,” in Proc. ASID’06, 2006, pp. 125-127.
[26] C. L. Lin*, and Y. C. Chen “A novel LTPS-TFT pixel circuit compensating for TFT threshold-voltage shift and OLED degradation for AMOLED,” IEEE Electron Device Letters, vol. 28, no. 2, pp. 129-131, Feb. 2007.
[27] H. J. In and O. K. Kwon, “A simple pixel structure using polycrystalline-silicon thin-film transistors for high-resolution active-matrix organic light-emitting diode displays,” IEEE Electron Device Letters, vol. 33, no. 7, pp. 1018-1020, Jul. 2012.
[28] J. H. Lee, W. J. Nam, S. H. Jung, and M. K. Han, “A new current scaling pixel circuit for AMOLED,” IEEE Electron Device Letters, vol. 25, no. 5, pp. 280-282, May 2004.
[29] Y. H. Tai, B. T. Chen, Y. J. Kuo, C. C. Tsai, K. Y. Chiang, Y. J. Wei, and H. C. Cheng, “A new pixel circuit for driving organic light emitting diodes with low temperature polycrystalline thin film transistors,” IEEE/OSA Journal of Display Technology, vol. 1, no. 1, pp. 100-104, Sep. 2005.
[30] J. H. Lee, J. H. Kim, and M. K. Han, “A new a-Si:H TFT pixel circuit compensating the threshold voltage shift of a-Si:H TFT and OLED for active matrix OLED,” IEEE Electron Device Letters, vol. 26, no. 12, pp. 897-899, Dec. 2005.
[31] H. Y. Lu, P. T. Liu, T. C. Chang, and S. Chi, “Enhancement of brightness uniformity by a new voltage-modulated pixel design for AMOLED displays,” IEEE Electron Device Letters, vol. 27, no. 9, pp. 743-745, Sep. 2006.
[32] S. H. Jung, W. J. Nam, and M. K. Han, “ A new voltage-modulated AMOLED pixel design compensating for threshold voltage variation in poly-Si TFTs, ” IEEE Electron Device Letters, vol. 25, no. 10, pp. 690-692, Sep. 2004.
[33] S. J. Song, Y. Chen, J. Jang, and H. Nam, “Hybrid voltage and current programming pixel circuit for high brightness simultaneous emission AMOLED display,” IEEE Journal of Display Technology, vol. 11, no. 3, pp. 255-260, Mar. 2015.
[34] N. H. Keum, H. J. In, K.W. Oh and O. K. Kwon, “Life time extension method for simultaneous emission driving AMOLED displays,” Electronics Letters, vol. 48, no. 23, Nov. 2012.
[35] C. L. Lin, P. S. Chen, M. Y. Deng, C. E. Wu, W. C. Chiu, and Y. S. Lin, “UHD AMOLED driving scheme of compensation pixel and gate driver circuits achieving high-speed operation, ” IEEE Journal of the Electron Devices Society, vol. 6, pp.26-33, 2018.
[36] C. L. Lin, P. C. Lai, P. C. Lai, T. C. Chu, and C. L. Lee, “Bidirectional gate driver circuit using recharging and time-division driving scheme for in-cell touch LCDs,” IEEE Transactions on Industrial Electronics, vol. 65, no. 4, pp.3585-3591, Apr. 2018.
[37] W. J. Wu, L. R. Zhang, Z. P. Xu, L. Zhou, H. Tao, J. H. Zou, M. Xu, L. Wang, and J. B. Peng, “A high-reliability gate driver integrated in flexible AMOLED display by IZO TFTs” IEEE Trans. Electron Devices, vol. 64, no. 5, pp.1991-1996, May 2017.