Abstract

In this paper, we propose a novel active touch panel circuit using the RC time constant changes when the panel is touched to induce pulse overlapping. The transient ON current of the pixel thin-film transistor (TFT) is to be detected for the judgment whether panel is touched or not. The proposed circuit has many advantages, such as simple structure, multi-touch, low operating power, as well as significant current to be read out easily by low cost ICs. Especially, it provides excellent stability since the circuit is hardly influenced by variation of TFTs. Discrete TFTs are used to build the proposed circuit to verify its function and the function is further demonstrated in a 2-inch 9×9 array. The potential for large area applications is proven by simulating a 42-inch touch panel with proper assumptions.

© 2013 IEEE

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  1. S. Tomita, T. Nakamura, T. Morita, T. Imai, T. Okada, H. Hayashi, Y. Saruhashi, M. Fuchi, M. Hashimoto, M. Tada, T. Endo, K. Saito, H. Nakamura, "An in-cell capacitive touch-sensor integrated in an LTPS WSVGA TFT-LCD," SID Symp. Dig. Tech. aper (2011) pp. 629-632.
  2. S. Takahashi, D. H. Cho., H.-S. Moon, N. De Kim, "In-cell embedded touch screen technology for large size LCD applications," SID Symp. Dig. Tech. Paper (2010) pp. 544-547.
  3. K. Tanaka, H. Kato, Y. Sugita, N. Usukura, H. Kawamori, K. Maeda, Y. Kubota, "A system LCD with optical input function using infra-red backlight subtraction scheme," SID Symp. Dig. Tech. Paper (2010) pp. 680-683.
  4. B. H. You, B. J. Lee, K.-C. Lee, S. Y. Han, J. H. Koh, J. H. Lee, S. Takahashi, R. H. Berkeley, N. D. Kim, S. S. Kim, "12.1-inch a-Si:H TFT LCD with embeded touch screen panel," SID Symp. Dig. Tech. Paper (2008) pp. 830-833.
  5. G. J. A. Destura1, J. T. M. Osenga, S. J. van der Hoef, "Novel touch sensitive in-cell AMLCD," SID Symp. Dig. Tech. Paper (2004) pp. 22-23.
  6. H.-S. Park, Y.-J. Kim, M.-K. Han, "Touch-sensitive active-matrix display with liquid-crystal capacitance detector arrays," Jpn. J. Appl. Phys. 49, 03CC01 (2010).
  7. C. S. Kim, B. K. Kang, J. H. Jung, M. J. Lee, H. B. Kim, S. S. Oh, S. H. Jang, H. J. Lee, H. Kastuyoshi, J. K. Shin, "Active matrix touch sensor perceiving liquid crystal capacitance with amorphous silicon thin film transistors," Jpn. J. Appl. Phys. 49, 03CC03 (2010).
  8. N. D. Young, G. Harkin, R. M. Bunn, D. J. McCulloch, R. W. Wilks, A. G. Knapp, "Novel fingerprint scanning arrays using polysilicon TFT's on glass and polymer substrates," IEEE Electron Device Lett. 18, 19-20 (1997).
  9. L.-S. Chou, H.-L. Chiu, K.-T. Lin, Y.-H. Tai, "Active matrix touch sensor detecting time-constant change implemented by IGZO TFTs," SID Symp. Dig. Tech. Paper (2011) pp. 1841-1844.
  10. Y.-H. Tai, H.-L. Chiu, L.-S. Chou, "Active matrix touch sensor detecting time-constant change implemented by dual-gate IGZO TFTs," Solid-State Electron. 72, 67-72 (2012).

2012 (1)

Y.-H. Tai, H.-L. Chiu, L.-S. Chou, "Active matrix touch sensor detecting time-constant change implemented by dual-gate IGZO TFTs," Solid-State Electron. 72, 67-72 (2012).

2010 (2)

H.-S. Park, Y.-J. Kim, M.-K. Han, "Touch-sensitive active-matrix display with liquid-crystal capacitance detector arrays," Jpn. J. Appl. Phys. 49, 03CC01 (2010).

C. S. Kim, B. K. Kang, J. H. Jung, M. J. Lee, H. B. Kim, S. S. Oh, S. H. Jang, H. J. Lee, H. Kastuyoshi, J. K. Shin, "Active matrix touch sensor perceiving liquid crystal capacitance with amorphous silicon thin film transistors," Jpn. J. Appl. Phys. 49, 03CC03 (2010).

1997 (1)

N. D. Young, G. Harkin, R. M. Bunn, D. J. McCulloch, R. W. Wilks, A. G. Knapp, "Novel fingerprint scanning arrays using polysilicon TFT's on glass and polymer substrates," IEEE Electron Device Lett. 18, 19-20 (1997).

IEEE Electron Device Lett. (1)

N. D. Young, G. Harkin, R. M. Bunn, D. J. McCulloch, R. W. Wilks, A. G. Knapp, "Novel fingerprint scanning arrays using polysilicon TFT's on glass and polymer substrates," IEEE Electron Device Lett. 18, 19-20 (1997).

Jpn. J. Appl. Phys. (2)

H.-S. Park, Y.-J. Kim, M.-K. Han, "Touch-sensitive active-matrix display with liquid-crystal capacitance detector arrays," Jpn. J. Appl. Phys. 49, 03CC01 (2010).

C. S. Kim, B. K. Kang, J. H. Jung, M. J. Lee, H. B. Kim, S. S. Oh, S. H. Jang, H. J. Lee, H. Kastuyoshi, J. K. Shin, "Active matrix touch sensor perceiving liquid crystal capacitance with amorphous silicon thin film transistors," Jpn. J. Appl. Phys. 49, 03CC03 (2010).

Solid-State Electron. (1)

Y.-H. Tai, H.-L. Chiu, L.-S. Chou, "Active matrix touch sensor detecting time-constant change implemented by dual-gate IGZO TFTs," Solid-State Electron. 72, 67-72 (2012).

Other (6)

L.-S. Chou, H.-L. Chiu, K.-T. Lin, Y.-H. Tai, "Active matrix touch sensor detecting time-constant change implemented by IGZO TFTs," SID Symp. Dig. Tech. Paper (2011) pp. 1841-1844.

S. Tomita, T. Nakamura, T. Morita, T. Imai, T. Okada, H. Hayashi, Y. Saruhashi, M. Fuchi, M. Hashimoto, M. Tada, T. Endo, K. Saito, H. Nakamura, "An in-cell capacitive touch-sensor integrated in an LTPS WSVGA TFT-LCD," SID Symp. Dig. Tech. aper (2011) pp. 629-632.

S. Takahashi, D. H. Cho., H.-S. Moon, N. De Kim, "In-cell embedded touch screen technology for large size LCD applications," SID Symp. Dig. Tech. Paper (2010) pp. 544-547.

K. Tanaka, H. Kato, Y. Sugita, N. Usukura, H. Kawamori, K. Maeda, Y. Kubota, "A system LCD with optical input function using infra-red backlight subtraction scheme," SID Symp. Dig. Tech. Paper (2010) pp. 680-683.

B. H. You, B. J. Lee, K.-C. Lee, S. Y. Han, J. H. Koh, J. H. Lee, S. Takahashi, R. H. Berkeley, N. D. Kim, S. S. Kim, "12.1-inch a-Si:H TFT LCD with embeded touch screen panel," SID Symp. Dig. Tech. Paper (2008) pp. 830-833.

G. J. A. Destura1, J. T. M. Osenga, S. J. van der Hoef, "Novel touch sensitive in-cell AMLCD," SID Symp. Dig. Tech. Paper (2004) pp. 22-23.

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