Lifetime Amelioration for an AMOLED Pixel Circuit by Using a Novel AC Driving Scheme

Autor:	Chia-Che Hung, Chun-Da Tu, Kuan-Wen Chou, Chih-Lung Lin
Rok vydání:	2011
Předmět:	Brightness Materials science business.industry Luminance Electronic Optical and Magnetic Materials Threshold voltage AMOLED Optics Duty cycle OLED Optoelectronics Electrical and Electronic Engineering business Diode Voltage
Zdroj:	IEEE Transactions on Electron Devices. 58:2652-2659
ISSN:	1557-9646 0018-9383
DOI:	10.1109/ted.2011.2151862
Popis:	This paper describes how a reversed-bias voltage affects organic light-emitting diodes (OLEDs) with green emitting Alq3:C545T (40 nm). The luminance efficiency and the active area of the test OLED devices are 8-11 cd/A and 2.5 mm × 2.5 mm, respectively. The OLED lifetime under an ac driving scheme can be apparently improved, in contrast with that under a dc driving scheme. Experimental results indicate that adjusting the duty ratio of the ac driving scheme can ameliorate the brightness uniformity; meanwhile, the normalized luminance of a 20% duty ratio after a 3600-s stress is 94.3%, and that of dc stress is 76.4%. Therefore, a novel pixel circuit with three p-type thin-film transistors (TFTs) for an active-matrix OLED application is proposed to ameliorate the brightness uniformity. Variations of the threshold voltage of the driving TFT are compensated for, and the performance and lifetime of the OLED are improved by using an ac driving method. Simulation results indicate that the output current is almost constant over the data range. Furthermore, the current error rate of the proposed pixel circuit is less than 6.5%.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7374e1ebc76e1fcae72c495599479376 https://doi.org/10.1109/ted.2011.2151862 Zobrazit plný text záznamu