The Amorphous Silicon Thin Film Transistor Compensation Pixel Circuit for Threshold Voltage Shift with Application to Organic Light Emitting Diode
Date Issued
2007
Date
2007
Author(s)
Chu, Yu-Ling
DOI
en-US
Abstract
The threshold voltage of hydrogenated amorphous silicon thin-film transistor(a-Si:H TFT) increases with time due to bias stress. This causes the driving current and
emitting brightness of organic light emitting diodes (OLED) to decay with time. Thus a new TFT voltage-programmed compensation pixel circuit for threshold voltage shift which consists of four transistors and one capacitor (4T1C) is proposed in this thesis. After a series of improvement in the design of the TFT structure and processing parameters, the TFT structure is optimized for the driving circuit of OLED. Both the simulation and experimental results reveal that the proposed 4T1C circuit can compensate the threshold voltage shift of the amorphous silicon TFT. Comparing to the traditional two transistors and one capacitor (2T1C) driving circuit, the new driving circuit gives a better compensation to the current degradation. In simulation, the theoretical current drop after a 30 minutes bias stress is in the range from 7% to 28 %, the current error of the proposed 4T1C driving circuit can be reduced to less than 3 %.
The experimental results indicate that the degradation of OLED current of the proposed 4T1C driving circuit could be improved to less than half of the traditional 2T1C pixel.
Subjects
非晶矽
薄膜電晶體
補償電路
amorphous silicon
TFT
compensation circuit
thin film transistor
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-96-R94943043-1.pdf
Size
23.31 KB
Format
Adobe PDF
Checksum
(MD5):f4be764a6715a47d59e26948a58c26d7