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A Novel Voltage-Programmed Pixel Circuit with Poly-Si TFTs for AMOLED Displays

Zunkai Huang

http://orcid.org/0000-0001-7501-8959

Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, P. R. China

University of Chinese Academy of Sciences, Beijing 100049, P. R. China

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Li Tian

Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, P. R. China

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Hui Wang

Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, P. R. China

E-mail Address: wanghui@sari.ac.cn

Corresponding author.

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, and

Songlin Feng

Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, P. R. China

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https://doi.org/10.1142/S0218126618502213Cited by:1 (Source: Crossref)

Abstract

In this paper, we propose a novel voltage-programmed pixel circuit with polysilicon thin–flim transistors (poly-Si TFTs) for active matrix organic light-emitting diode (AMOLED) displays, which consists of one programming transistor, one driving transistor, four switching transistors and two storage capacitors, respectively. Specifically, the proposed pixel circuit is able to not only efficiently compensate for the threshold variations of TFTs, but also largely suppresses the electrical degradations of the devices caused by the long-term electrical stress. Moreover, the mobility variation of the driving transistor can be compensated as well. The simulation has been performed by HSPICE, and results indicate that the average values of nonuniformities are, respectively, 7.3% as the threshold-voltage varies by $\pm 0.5$ $\pm 0.5$ V and 2.1%, as the mobility of the driving transistor varies by $\pm 20$ $\pm 20$ %, both of which are much lower than that of the conventional two-transistor and one-capacitor (2T1C) pixel. Furthermore, since the OLED is reverse-biased during the nonemission phases, the lifetime of OLED will be extended naturally. As a consequence, the proposed pixel circuit can substantially improve the display performance.

This paper was recommended by Regional Editor Piero Malcovati.

Keywords:

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