Pulse-Width Modulation with Current Uniformization for TFT-OLEDs

Mutsumi KIMURA  Shigeki SAWAMURA  Masakazu KATO  Yuji HARA  Daisuke SUZUKI  Hiroyuki HARA  Satoshi INOUE  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E90-C   No.11   pp.2076-2082
Publication Date: 2007/11/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.11.2076
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Section on Electronic Displays)
Category: 
Keyword: 
pulse-width modulation,  current uniformization,  TFT-OLED,  circuit simulation,  characteristic compensation,  luminance uniformity,  

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Summary: 
A novel driving concept, "pulse-width modulation with current uniformization," is proposed for thin-film transistor driven organic light-emitting diode displays (TFT-OLEDs). An example of this driving concept is the combination of "pulse-width modulation with a self-biased inverter" and a "time-ratio grayscale with current uniformization." Its driving operation is confirmed by circuit simulation. It is found that this driving method can compensate the characteristic deviations and degradations of both TFTs and OLEDs and immensely improve luminance uniformity. Finally, its driving operation is also confirmed by an actual pixel equivalent circuit.