A Pixel Circuit for Compensating Electrical Characteristics Variation and OLED Degradation

Ning Wei; Hongzhen Chu; Bo Yu; Huicheng Zhao; Yuehua Li; Xinlin Wang; Hongyu He

doi:10.3390/mi14040857

A Pixel Circuit for Compensating Electrical Characteristics Variation and OLED Degradation

Micromachines (Basel). 2023 Apr 15;14(4):857. doi: 10.3390/mi14040857.

Authors

Ning Wei^{1

2}, Hongzhen Chu¹, Bo Yu¹, Huicheng Zhao¹, Yuehua Li¹, Xinlin Wang¹, Hongyu He^{1

2}

Affiliations

¹ School of Electrical Engineering, University of South China, Hengyang 421001, China.
² School of Electronics and Information, Yangtze University, Jingzhou 434023, China.

Abstract

In recent years, the active-matrix organic light-emitting diode (AMOLED) displays have been greatly required. A voltage compensation pixel circuit based on an amorphous indium gallium zinc oxide thin-film transistor is presented for AMOLED displays. The circuit is composed of five transistors-two capacitors (5T2C) in combination with an OLED. In the circuit, the threshold voltages of both the transistor and the OLED are extracted simultaneously in the threshold voltage extraction stage, and the mobility-related discharge voltage is generated in the data input stage. The circuit not only can compensate the electrical characteristics variation, i.e., the threshold voltage variation and mobility variation, but also can compensate the OLED degradation. Furthermore, the circuit can prevent the OLED flicker, and can achieve the wide data voltage range. The circuit simulation results show that the OLED current error rates (CERs) are lower than 3.89% when the transistor's threshold voltage variation is ±0.5V, lower than 3.49% when the mobility variation is ±30%.

Keywords: OLED degradation; mobility variation; pixel circuit; threshold voltage variation; voltage programming.

Grants and funding

This research was funded by [The Hunan Province Key Laboratory for Ultra-Fast Micro/Nano Technology and Advanced Laser Manufacture] grant number [No. 2018TP1041].