scholarly journals New Low-Frame-Rate Compensating Pixel Circuit Based on Low-Temperature Poly-Si and Oxide TFTs for High-Pixel-Density Portable AMOLED Displays

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1514
Author(s):  
Ching-Lin Fan ◽  
Wei-Yu Lin ◽  
Chun-Yuan Chen
Keyword(s):  
Low Temperature ◽  
Light Emitting Diode ◽  
Error Rates ◽  
Frame Rate ◽  
Driving Voltage ◽  
Active Matrix ◽  
Organic Light Emitting Diode ◽  
Voltage Variation ◽  
Pixel Circuit ◽  
Low Frame Rate

A new low-frame-rate active-matrix organic light-emitting diode (AMOLED) pixel circuit with low-temperature poly-Si and oxide (LTPO) thin-film transistors (TFTs) for portable displays with high pixel density is reported. The proposed pixel circuit has the excellent ability to compensate for the threshold voltage variation of the driving TFT (ΔVTH_DTFT). By the results of simulation based on a fabricated LTPS TFT and a-IZTO TFT, we found that the error rates of the OLED current were all lower than 2.71% over the range of input data voltages when ΔVTH_DTFT = ±0.33 V, and a low frame rate of 1 Hz could be achieved with no flicker phenomenon. Moreover, with only one capacitor and two signal lines in the pixel circuit, a high pixel density and narrow bezel are expected to be realized. We revealed that the proposed 7T1C pixel circuit with low driving voltage and low frame rate is suitable for portable displays.

A Novel Voltage-Programmed Pixel Circuit with Poly-Si TFTs for AMOLED Displays

2018 ◽  
Vol 27 (14) ◽  
pp. 1850221
Author(s):  
Zunkai Huang ◽  
Li Tian ◽  
Hui Wang ◽  
Songlin Feng
Keyword(s):  
Threshold Voltage ◽  
Light Emitting Diode ◽  
Active Matrix ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Electrical Stress ◽  
Organic Light ◽  
Pixel Circuit ◽  
Display Performance

In this paper, we propose a novel voltage-programmed pixel circuit with polysilicon thin–flim transistors (poly-Si TFTs) for active matrix organic light-emitting diode (AMOLED) displays, which consists of one programming transistor, one driving transistor, four switching transistors and two storage capacitors, respectively. Specifically, the proposed pixel circuit is able to not only efficiently compensate for the threshold variations of TFTs, but also largely suppresses the electrical degradations of the devices caused by the long-term electrical stress. Moreover, the mobility variation of the driving transistor can be compensated as well. The simulation has been performed by HSPICE, and results indicate that the average values of nonuniformities are, respectively, 7.3% as the threshold-voltage varies by [Formula: see text][Formula: see text]V and 2.1%, as the mobility of the driving transistor varies by [Formula: see text]%, both of which are much lower than that of the conventional two-transistor and one-capacitor (2T1C) pixel. Furthermore, since the OLED is reverse-biased during the nonemission phases, the lifetime of OLED will be extended naturally. As a consequence, the proposed pixel circuit can substantially improve the display performance.

An active-matrix organic light-emitting-diode pixel circuit for the compensation of I × R voltage drop in power line

2007 ◽  
Vol 15 (8) ◽  
pp. 541 ◽  
Author(s):  
Sang-Hoon Jung ◽  
Hong-Koo Lee ◽  
Tae-Joon Ahn ◽  
Chang-Yeon Kim ◽  
Chang-Dong Kim ◽  
...  
Keyword(s):  
Voltage Drop ◽  
Light Emitting Diode ◽  
Power Line ◽  
Active Matrix ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Pixel Circuit
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