非晶矽薄膜電晶體及非晶相銦鎵鋅氧化物電晶體為當前廣泛應用於主動式液晶顯示器之閘極驅動電路及畫素電路，此兩種電晶體與低溫多晶矽薄膜電晶體相比，皆具有較高的均勻性、較低的成本及較小的漏電流。此外，非晶相銦鎵鋅氧化物電晶體的載子移動率又比非晶矽薄膜電晶體高，因此使用非晶相銦鎵鋅氧化物電晶體製作畫素電路可以增加驅動力，進而降低電路的佈局面積。然而，非晶矽薄膜電晶體以及非晶相銦鎵鋅氧化物電晶體僅有N型，導致無法直接實現CMOS電路。此外，非晶矽薄膜電晶體以及非晶相銦鎵鋅氧化物電晶體經長時間偏壓後會產生嚴重的臨界電壓飄移。因此在設計主動式矩陣液晶顯示器之閘極驅動電路及畫素電路時，以上所述之議題皆是設計重點。
本論文提出了兩個新式非晶矽薄膜電晶體閘極驅動電路以及一個新式非晶相銦鎵鋅氧化物薄膜電晶體藍相液晶畫素電路，並經由模擬軟體驗證所提出電路之可行性。第一個電路為非晶矽薄膜電晶體閘極驅動電路，由八顆電晶體與三顆電容所組成，其應用於高解度之液晶顯示器，特色為利用電容耦合效應將驅動電晶體的閘極端抬升兩次以達到較高的電位，藉此可以更快速地將輸出點放電至低電位。根據模擬結果，經適當設計兩顆儲存電容的電容值，其下降時間只需1.42 μs。第二個電路為非晶矽薄膜電晶體閘極驅動電路，由十二顆電晶體與三顆電容所組成，其適用於內嵌式觸控面板。為了增加回報率以及防止觸控訊號受到干擾，顯示操作在ㄧ畫面時間內停止八次以執行觸控偵測。本電路在當觸控偵測啟動時，驅動電晶體被關閉以抑制其臨界電壓飄移。透過模擬證明，此電路在觸控偵測前後皆能產生穩定的輸出波形。第三個電路為一精簡架構之畫素電路，由三顆非晶相銦鎵鋅氧化物薄膜電晶體與兩顆電容所組成，其適用於藍相液晶顯示器，特色為利用電容耦合效應將輸出節點之電壓準位抬升為所輸入資料電壓的兩倍。模擬結果顯示當輸入電壓範圍為0 V至15 V時，輸出節點電壓範圍可達到0.342 V至29.6 V。

Hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) and amorphous indium-gallium-zinc oxide (a-IGZO) TFTs have been widely used in the gate driver circuits and pixel circuits of the active-matrix liquid crystal displays due to their higher uniformity, lower manufacturing cost, and lower leakage currents than low-temperature polycrystalline (LTPS) TFTs. Moreover, a-IGZO TFTs have higher mobility than a-Si:H TFTs, and thus pixel circuits based on a-IGZO TFTs can enhance driving capability, decreasing the overall layout area. Nevertheless, both a-Si:H and a-IGZO technologies only have n-type TFTs, so the complementary metal-oxide-semiconductor (CMOS) circuits cannot be implemented by them directly. Furthermore, a-Si:H and a-IGZO TFTs have the severe threshold voltage shift which results from bias under long-term stress. In summary, the aforementioned issues must be considered in the design of the gate driver circuit and the pixel circuit using n-type TFTs.
This thesis proposes two a-Si:H gate driver circuits and one a-IGZO pixel circuit of blue phase liquid crystal displays (BPLCDs), and the feasibility of the proposed circuits is verified by the HSPICE simulator. The first a-Si:H gate driver circuit, consisting of eight TFTs and three capacitors, is suitable for high-resolution panels. The gate node of the driving TFT is bootstrapped twice to a higher voltage level by the capacitive coupling effect, so the output node can be discharged faster to a low voltage level. According to the simulation results, the falling time of the output waveform is only 1.42 μs when the capacitance of two storage capacitors is chosen properly. The second a-Si:H gate driver circuit is composed of 12 TFTs and three capacitors for use in in-cell touch panels. To increase the report rate and prevent display-to-touch crosstalk (DTX), the display operation stops eight times to perform touch sensing period in the frame time. In this work, the driving TFT is turned off to suppress the threshold voltage shift during the touch sensing period. Based on the simulation results, stable output waveforms are successfully generated before and after the touch sensing period. The third proposed design is a simple pixel circuit that comprises three a-IGZO TFTs and two capacitors for use in BPLCDs. The coupling method is utilized to produce the wide output voltage range that is twice the data voltage range supplied by the source driver integrated circuit. Simulation results show that the output voltage range of 0.342 V to 29.6 V can be achieved with a 0 V to 15 V input voltage range.

[1] H. Kristiansen and J. Liu, “Overview of conductive adhesive interconnection technologies for LCDs,” IEEE Trans. Compon., Packag., Manuf. Technol. A, vol. 21, no. 2, pp. 208–214, Jan. 1998.
[2] 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.
[3] Y. H. Tai, “Design and operation of TFT-LCD panels,” Wunan, 2006.
[4] R. Joshi, “Chip on glass-interconnect for row/column driver packaging,” Microelectr. J., vol. 29, pp. 343–349, Jun. 1998.
[5] J. Liu, “ACA bonding technology for low cost electronics packaging applications current status and remaining challenges,” in Proc. 4th Int. Conf. Adhesive Joining and Coating Technology Electronic Manufacturing, pp. 1–15, 2000.
[6] C. T. Liu, “Revolution of the TFT LCD technology,” J. Display Technol., vol. 3, no. 4, pp. 342–350, Dec. 2007.
[7] J. C. Hwang, “Advanced low-cost bare-DIE packaging technology for liquid crystal displays,” IEEE Trans. Compon., Packag., Manuf. Technol. A, vol. 18, no. 3, pp. 458–461, Mar. 1995.
[8] C. Hordequin, J. M. Bayot, T. Kretz, S. Yon, S. Arfuso, N. Szydlo, and H. Lebrun, “A 1” VGA LC light valve using a-Si:H TFTs with integrated drivers,” EuroDisplay 02, pp. 387–390, 2002.
[9] S. H. Lo, C. C. Wei, W. C. Lin, I. Wang, C. C. Shih, and Y. E. Wu, “Integrated gate driver circuit with one conduction path for charge-discharge,” in Soc. Inf. Display Symp. Dig. Tech. Papers, vol. 37, no. 1, pp. 231–234, Jun. 2006.
[10] 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 Soc. Inf. Display Symp. Dig. Tech. Papers, vol. 38, no. 1, pp. 1478–1481, May 2007.
[11] Y. T. Tai, W. L. Pearn, K. B. Huang, and L. W. Liao, “Capability assessment for weibull in-cell touch panel manufacturing process with variance change” IEEE Trans. Semiconductor Manufacturing, vol. 27, no. 2, pp. 184–191, May 2014.
[12] 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” J. Display Technol., vol. 12, no. 5, pp. 435–441, May 2016.
[13] C. Kim, D. S. Lee, H. B. Kim, S. R. Shin, J. H. Jung, I. H. Song, C. S. Jang, K. S. Kwon, S. H. Kim, G. T. Kim, J. H. Yoon, B. Y. Lee, B. K. Kim, and I. B. Kang, “Advanced in-cell touch technology for large sized liquid crystal displays,” in Soc. Inf. Display Symp. Dig. Tech. Papers, vol. 46, no. 1, pp. 895–898, Jun. 2005.
[14] B. J. Yan, L. Rao, M. Jiao, Y. Li, H. C. Cheng, and S. T. Wu, “Polymer-stabilized optically isotropic liquid crystals for next-generation display and photonic applications,” J. Mater. Chem., vol. 21, pp. 7870–7877, 2011.
[15] K. M. Chen, S. Gauza, H. Xianyu, and S. T. Wu, “Submillisecond gray level response time of a polymer-stabilized blue-phase liquid crystal,” J. Display Technol., vol. 6, no. 2, pp. 49–51, Feb. 2010.
[16] Y. Chen, J. Yan, J. Sun, S. T. Wu, X. Liang, S. H. Liu, P. J. Hsieh, K. L. Cheng, and J. W. Shiu, “A microsecond-response polymer-stabilized blue phase liquid crystal,” Appl. Phys. Lett., vol. 99, no. 20, p. 201105, 2011.

[17] Z. Ge, S. Gauza, M. Jiao, H. Xianyu, and S. T. Wu, “Electro-optics of polymer-stabilized blue phase liquid crystal displays,” Appl. Phys. Lett., vol. 94, no. 10, p. 101104, 2009.
[18] L. Rao, Z. Ge, S. T. Wu, and S. H. Lee, “Low voltage blue-phase liquid crystal displays,” Appl. Phys. Lett., vol. 95, no. 23, p. 231101, 2009.
[19] M. Jiao, Y. Li, and S. T. Wu, “Low voltage and high transmittance blue-phase liquid crystal displays with corrugated electrodes,” Appl. Phys. Lett., vol. 96, no. 1, p. 011102, 2010.
[20] L. Rao, H. C. Cheng, and S. T. Wu, “Low voltage blue-phase LCDs with double-penetrating fringe fields,” J. Display Technol., vol. 6, no. 8, pp. 287–289, Aug. 2010.
[21] H. C. Cheng, J. Yan, T. Ishinabe, and S. T. Wu, “Vertical field switching for blue-phase liquid crystal devices,” Appl. Phys. Lett., vol. 98, no. 26, p. 261102, 2011.
[22] H. Lee, H. J. Park, O. J. Kwon, S. J. Yun, J. H. Park, S. Hong, and S. T. Shin, “The world’s first blue phase liquid crystal display,” in Soc. Inf. Display Symp. Dig. Tech. Papers, vol. 42, no. 1, pp. 121–124, Jun. 2011.
[23] G. Kawachi, M. Ishii, and N. Konishi, “Transient behavior of a-Si:H/Si3N4 MIS capacitor and its impact in image quality of AMLCDs addressed by a-Si:H thin-film transistors,” J. Display Technol., vol. 3, no. 1, pp. 52–56, Mar. 2007.
[24] J. W. Park, I. H. Song, M. K. Han, and N. Konishi, “Recessed gate-data line-crossover structures employing an air-gap to reduce signal delay for TFT-LCD panel,” IEEE Trans. Electron Devices, vol. 48, no. 12, pp. 2716–2721, Dec. 2001.
[25] Y. S. Son and G. H. Cho, “Design considerations of channel buffer amplifiers for low-power area-efficient column drivers in active-matrix LCDs,” IEEE Trans. Consumer Electronics, vol. 54, no. 2, pp. 648–656, May 2008.
[26] A. Nathan, G. R. Chaji, and S. J. Ashtiani, “Driving schemes for a-Si and LTPS AMOLED display,” J. Display Technol., vol. 1, no. 2, pp. 267–277, Dec. 2005.
[27] C. L. Lin and T. T. Tsai, “A novel voltage driving method using 3-TFT pixel circuit for AMOLED,” IEEE Electron Device Lett., vol. 28, no. 6, pp. 489–491, Jun. 2007.
[28] S. Sambandan and A. Nathan, “Single-technology-based statistical calibration for high-performance active-matrix organic LED display,” J. Display Technol., vol. 3, no. 3, pp. 284–294, Sep. 2007.
[29] C. Liao, C. He, T. Chen, D. Dai, S. Chung, T. S. Jen, and S. Zhang, “Design of integrated amorphous-silicon thin-film transistor gate driver,” J. Display Technol., vol. 9, no. 1, pp. 7–16, Jan. 2013.
[30] B. S. Bae, J. W. Choi, J. H. Oh, and J. Jang, “Level shifter embedded in driver circuits with amorphous silicon TFTs,” IEEE Trans. Electron Devices, vol. 53, no. 3, pp. 494–498, Mar. 2006.
[31] J. W. Choi, M. S. Kwon, J. H. Koo, J. H. Park, S. H. Kim, D. H. Oh, S. W. Lee, and J. Jang, “Noble a-Si:H gate driver with high stability,” in Soc. Inf. Display Symp. Dig. Tech. Papers, vol. 39, no. 1, pp. 1227–1230, May 2008.
[32] C. L. Lin, C. D. Tu, C. E. Wu, C. C. Hung, K. J. Gan, and K. W. Chou, “Low-power gate driver circuit for TFT-LCD application,” IEEE Trans. Electron Devices, vol. 59, no. 5, pp. 1410–1415, May 2012.
[33] J. W. Choi, J. I. Kim, S. H. Kim, and J. Jang, “Highly reliable amorphous silicon gate driver using stable center-offset thin-film transistors,” IEEE Trans. Electron Devices, vol. 57, no. 9, pp. 2330–2334, Sep. 2010.
[34] C. L. Lin, M. H. Cheng, C. D. Tu, C. C. Hung, and J. Y. Li, “2-D-3-D switchable gate driver circuit for TFT-LCD applications,” IEEE Trans. Electron Devices, vol. 61, no. 6, pp. 2098–2105, Jun. 2014.
[35] C. L. Lin, C. D. Tu, M. C. Chung, and J. S. Yu, “Design of bidirectional and highly stable integrated hydrogenated amorphous silicon gate driver circuits,” J. Display Technol., vol. 7, no. 1, pp. 10–18, Jan. 2011.
[36] F. Mautice, H. Lebrun, N. Szydlo, U. Rossini, and R. Chaudet, “High resolution projection valve with the amorphous silicon AMLCD technology,” Proc. SPIE, vol. 3296, pp. 92–99, Jan. 1998.
[37] C. D. Tu, C. L. Lin, J. Yan, Y. Chen, P. C. Lai, and S. T. Wu, “Driving scheme using bootstrapping method for blue-phase LCDs,” J. Display Technol., vol. 9, no. 1, pp. 3–6, Jan. 2013.
[38] S. J. Yoo, S. J. Hong, J. S.Kang, H. J. In, and O. K. Kwon, “A low-power single-clock-driven scan driver using depletion-mode a-IGZO TFTs,” IEEE Electron Device Lett., vol. 33, no. 3, pp. 402-404, Mar. 2012.
[39] C. L. Lin, M. H. Cheng, C. D. Tu, and M. C. Chuang, “Highly reliable integrated gate driver circuit for large TFT-LCD applications,” IEEE Electron Device Lett., vol. 33, no. 5, pp. 679–681, May 2012.
[40] C. L. Lin, M. H. Cheng, C. D. Tu, C. E. Wu, and F. H. Chen, “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.
[41] C. L. Lin, F. H. Chen, Y. W. Du, and M. H. Cheng, “Simplified gate driver circuit for high-resolution and narrow-bezel thin-film transistor liquid crystal display applications,” IEEE Electron Device Lett., vol. 36, no. 8, pp. 808–810, Aug. 2015.
[42] L. W. Chu, P. T. Liu, and M. D. Ker, “Design of integrated gate driver with threshold voltage drop cancellation in amorphous silicon technology for TFT-LCD application,” J. Display Technol., vol. 7, no. 12, pp. 657–664, Dec. 2011.
[43] D. A. Stronks, A. Al-Dahle, and W. H. Yao, “Devices and methods for reduction of display to touch crosstalk,” United States Patent, No. 0084911, 2015.
[44] S. Y. Lee, S. C. Kim, and S. E. Pyo, “Display device with integrated touch screen and method of driving the same,” United States Patent, No. 0320427, 2014.
[45] C. L. Lin, C. E. Wu, M. H. Cheng, B. S. Tzeng, C. H. Lin, N. Sugiura, and S. T. Wu, “New blue-phase LCD driving pixel circuit for a-IGZO TFT with large operation voltage,” in Soc. Inf. Display Symp. Dig. Tech. Papers, vol. 45, no. 1, pp. 1157–1159, Jun. 2014.
[46] D. Shim, K. J. Kim, Y. S. Cho, J. M. Choi, S. J. Yee, T. H. Kim, S. W. Cho, J. Y. Lee, G. T. Kang, M. C. Jun, and I. B. Kang, “Novel pixel structure for quadrupling of pixel voltage,” in Soc. Inf. Display Symp. Dig. Tech. Papers, vol. 45, no. 1, pp. 713–715, Jun. 2014.