A New Voltage-Programmed Pixel Circuit for Enhancing the Uniformity of AMOLED Displays

Author

Wu, Wei-Jing ; Zhou, Lei ; Yao, Ruo-He ; Peng, Jun-Biao

Author_Institution

Inst. of Polymer Optoelectron. Mater. & Devices, South China Univ. of Technol., Guangzhou, China

Volume

32

Issue

7

fYear

2011

fDate

7/1/2011 12:00:00 AM

Firstpage

931

Lastpage

933

Abstract

This letter presents a new voltage-programmed pixel circuit for the active-matrix organic light-emitting diode (AMOLED) displays, which consists of one driving thin-film transistor (TFT), four switching TFTs, two capacitors, and three control signal lines. The proposed pixel circuit can effectively compensate for the threshold-voltage shift of the driving TFT and the OLED degradation, which is verified by the simulation work using SMART-SPICE software. It is shown that the average nonuniformity of the OLED current for the proposed pixel circuit is 5.7% compared with 85.7% for the conventional 2T1C pixel circuit, and thus, the brightness uniformity of AMOLED displays can be enhanced. Moreover, a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period.

Keywords

LED displays; capacitors; organic light emitting diodes; thin film transistors; AMOLED displays; SMART-SPICE software; active-matrix organic light-emitting diode; capacitors; control signal lines; thin-film transistor; threshold-voltage shift; voltage-programmed pixel circuit; Active matrix organic light emitting diodes; Capacitors; Degradation; Pixel; Thin film transistors; Threshold voltage; Active-matrix organic light-emitting diode (AMOLED); pixel circuit; uniformity;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2011.2148152

Filename

5771048