Abstract

In this paper, we examine the effect of switch thin-film transistor (TFT) leakage and charge injection on the operation and driving of amorphous silicon (a-Si) active matrix organic light-emitting diode (AMOLED) displays. Charge injection causes an undesirable and immediate drop in the data voltage stored on the storage capacitor C<sub>S</sub> when the switch TFT is turned off, and the leakage of the switch TFT causes the charge on C<sub>S</sub> to gradually leak out over the frame time. While making the row line negative helps reduce the leakage, it increases the voltage swing on the row line and causes more charge injection. We have demonstrated that for a given V<sub>DD</sub>, there is an optimal negative gate drive voltage on the switch TFT that minimizes the overall drop in data voltage on C<sub>S</sub> over the frame time. In addition, we have also shown that even though this optimal driving point changes with aging of the display since both leakage and V<sub>T</sub> increase over time, it is possible to keep the voltage drop on C<sub>S</sub> constant irrespective of aging. The analysis provides the designer with a means to improve the long term grey-scale performance of the AMOLED display.

© 2006 IEEE

PDF Article

References

  • View by:
  • |

  1. Y. Kuo, Thin Film Transistors, Materials and Processes Volume 1: Amorphous Silicon Thin Film Transistors (Kluwer Academic, 2004).
  2. D. A. Johns, K. Martin, Analog Integrated Circuit Design (Wiley, 1997) pp. 308-311.
  3. K. Sakariya, P. Servati, A. Nathan, "Stability analysis of current programmed a-Si:H AMOLED pixel circuits," IEEE Trans. Electron Devices 51, 2019-2025 (2004).
  4. Y. He, R. Hattori, J. Kanicki, "Current-source a-Si:H thin-film transistor circuit for active-matrix organic light-emitting displays," IEEE Electron Device Lett. 21, 590-592 (2000).
  5. J. Shieh, M. Patil, B. J. Sheu, "Measurement and analysis of charge injection in MOS analog switches," IEEE J. Solid-State Circuits SC-22, 277-281 (1987).
  6. P. Servati, A. Nathan, "Modeling of the static and dynamic behaviour of hydrogenated amorphous silicon thin-film transistors," J. Vacuum Sci. Technol. A 20, 1038-1042 (2002).
  7. M. J. Powell, C. van Berkel, J. R. Hughes, "Time and temperature dependence of instability mechanisms in amorphous silicon thin-film transistors," App. Phys. Lett. 54, 1323-1325 (1989).

App. Phys. Lett.

M. J. Powell, C. van Berkel, J. R. Hughes, "Time and temperature dependence of instability mechanisms in amorphous silicon thin-film transistors," App. Phys. Lett. 54, 1323-1325 (1989).

IEEE Electron Device Lett.

Y. He, R. Hattori, J. Kanicki, "Current-source a-Si:H thin-film transistor circuit for active-matrix organic light-emitting displays," IEEE Electron Device Lett. 21, 590-592 (2000).

IEEE J. Solid-State Circuits

J. Shieh, M. Patil, B. J. Sheu, "Measurement and analysis of charge injection in MOS analog switches," IEEE J. Solid-State Circuits SC-22, 277-281 (1987).

IEEE Trans. Electron Devices

K. Sakariya, P. Servati, A. Nathan, "Stability analysis of current programmed a-Si:H AMOLED pixel circuits," IEEE Trans. Electron Devices 51, 2019-2025 (2004).

J. Vacuum Sci. Technol. A

P. Servati, A. Nathan, "Modeling of the static and dynamic behaviour of hydrogenated amorphous silicon thin-film transistors," J. Vacuum Sci. Technol. A 20, 1038-1042 (2002).

Other

Y. Kuo, Thin Film Transistors, Materials and Processes Volume 1: Amorphous Silicon Thin Film Transistors (Kluwer Academic, 2004).

D. A. Johns, K. Martin, Analog Integrated Circuit Design (Wiley, 1997) pp. 308-311.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.