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A fast 2‐transistor current‐mode AMOLED pixel
Author(s) -
Stewart Roger G.
Publication year - 2011
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1889/jsid19.7.503
Subject(s) - pixel , amoled , oled , transistor , computer science , thin film transistor , compensation (psychology) , active matrix , threshold voltage , current mirror , voltage , materials science , electrical engineering , computer vision , engineering , psychology , layer (electronics) , psychoanalysis , composite material
— Active‐matrix OLEDs are thinner and potentially more energy efficient than AMLCDs; however, most current AMOLED pixel designs are also excessively complicated. This paper compares the operating principles and performance of the four basic types of OLED pixels: converter pixels, system compensation pixels, compensated pixels, and current‐mode pixels. A new current‐mode pixel is described that is fast, provides excellent compensation for processing variations, and yet retains the simplicity and manufacturing advantages of the simplest 2‐transistor OLED pixels. Like other current‐mode pixels, this sequential current mirror pixel provides excellent compensation for variations in TFT V t , TFT mobility, and non‐uniformities in the OLED itself. However, unlike other current‐mode pixels that are too slow for use in large displays, this sequential current mirror pixel can operate with a voltage precharge in a superlinear mode to reduce data line settling delays to less than 3 μsec. Like the simplest uncompensated pixels, the compensated sequential current mirror pixel requires only two TFTs, a single data line, and a single select line.