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This work presents a new voltage programmed pixel circuit for an active-matrix organic light-emitting diode(AMOLED) display.The proposed pixel circuit consists of six low temperature polycrystalline silicon thinfilm transistors(LTPS TFTs),one storage capacitor,and one OLED,and is verified by simulation work using HSPICE software.Besides effectively compensating for the threshold voltage variation of the driving TFT and OLED,the proposed pixel circuit offers an AC driving mode for the OLED,which can suppress the degradation of the OLED.Moreover,a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period. 相似文献
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本文对一种LTPS-TFT AMOLED电压型阈值电压(V_(th))补偿像素电路进行了理论研究,分析了影响V_(th)补偿效果的主要因素。电路的补偿效果主要由驱动TFTV_(th)的获取精度和随后的保持精度决定。在V_(th)获取过程中,相关误差主要由驱动TFT转移特性电流对存储电容充电的充电率不足产生;在显示信号与V_(th)叠加过程中,与V_(th)保持节点连接的电容增量等因素会造成V_(th)保持精度的损失。根据分析的结果,本文解释了高分辨率像素电路补偿效果下降的原因。 相似文献
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有机发光二极管显示器(OLED)正越来越多地用于中小尺寸的显示,但在大尺寸方面进展缓慢,因为在有源大尺寸方面对OLED的稳定性和均匀性要求较高,需要设计像素补偿电路。各研究机构提出了像素补偿电路用于改善OLED的均匀性和稳定性等问题,文中对目前采用有源OLED的α-Si TFT和p-Si TFT的各种像素补偿电路进行了分析。分析结果表明,文中设计方案取得了一定的效果,但尚存不足。 相似文献
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为了防止有机发光二极管(organic light-emitting diode,OLED)显示器随着使用时间增加而造成OLED像素驱动电路发生阈值电压和电源电压漂移,从而引起显示屏亮度不均匀和不稳定的现象,本文对OLED像素补偿驱动电路进行研究。首先对通用型的2T1C驱动电路进行分析,找出引起显示器亮度不均匀和不稳定的原因,然后以目前使用较多的4T1C像素补偿驱动电路为例,对该电路进行了深入的分析,指出这种电路结构的缺陷,最后针对这些缺陷,提出了改进的5T1C像素补偿驱动电路,并且对该电路进行了仿真,验证了其可行性。仿真结果表明,在显示阶段,输出电流稳定在2μA。基本可以改善OLED显示器亮度不稳定和不均匀的缺点。 相似文献
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文中建立一种基于有机半导体TFT器件的模型,并将其应用于基于有机TFT的AMOLED显示背板驱动电路设计,以实现阈值电压补偿功能。首先制备低压有机TFT器件,并利用PSPICE工具对有机TFT器件进行建模;然后详细分析选取模型参数,建立能够准确反映器件电学特性的模型;最后基于模型指导,设计采用有机TFT的7T1C结构的AMOLED像素驱动电路。此外,分析有机TFT器件具有的温度依赖迁移率特性对屏幕亮度均匀性产生的影响。仿真结果表明:AMOLED像素驱动电路可有效实现对TFT器件阈值电压的补偿;且屏幕亮度不一致率低于5%,远低于传统的2T1C像素驱动电路,可大幅降低屏幕亮度的不均匀性。文中建立的有机TFT模型也可为其他基于有机器件的电路设计提供指导。 相似文献
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用于AM-OLED的LTPS TFTs的阈值电压(Vth)和沟道迁移率(μ)在空间分布上是不够均匀的,用于AM-OLED的a-Si TFTs的Vth和μ会随时间偏移,这些缺点会造成显示屏亮度的不均匀性和不稳定性.为此,需要引入各种像素补偿电路,使显示屏发光亮度的均匀性和稳定性符合商品要求(文章分为两期刊登,本篇为第一部... 相似文献
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A new voltage programmed pixel circuit with top emission design for active-matrix organic lightemitting diode(AMOLED) displays is presented and verified by HSPICE simulations.The proposed pixel circuit consists of five poly-Si TFTs,and can effectively compensate for the threshold voltage variation of the driving TFT.Meanwhile,the proposed pixel circuit offers an AC driving mode for the OLED by the two adjacent pulse voltage sources,which can suppress the degradation of the OLED.Moreover,a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period. 相似文献
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In this paper, four different driver circuits for an active matrix organic light-emitting diode (AMOLED) pixel based on thin film transistor (TFT) technology are analyzed and compared. In particular, the comparison analyzed accuracy, driving speed, power consumption and area occupied. Moreover, in order to allow array simulations, the RC equivalent models of the pixel were also derived. The results were achieved considering a QVGA display (320×240), a line frequency of 60 Hz, and were verified by simulations with AIM-SPICE. 相似文献
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Jae-Hoon Lee Woo-Jin Nam Sang-Hoon Jung Min-Koo Han 《Electron Device Letters, IEEE》2004,25(5):280-282
A new active-matrix organic light-emitting diode (AMOLED) pixel design, composed of four polycrystalline silicon thin-film transistor (poly-Si TFT) and one capacitor, is proposed by employing a novel current scaling scheme. The simulation results, based on the measured characteristics of an OLED and poly-Si TFTs, show that the proposed pixel design would scale down the data current more effectively, so as to guarantee a lower charging time compared with the conventional current mirror structure, as well as successfully compensate the variation of the electrical characteristics of the poly-Si TFTs, such as the threshold voltage and mobility. 相似文献
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A new voltage-modulated AMOLED pixel design compensating for threshold voltage variation in poly-Si TFTs 总被引:3,自引:0,他引:3
Sang-Hoon Jung Woo-Jin Nam Min-Koo Han 《Electron Device Letters, IEEE》2004,25(10):690-692
A new voltage-modulated active-matrix organic light-emitting diode (AMOLED) pixel design, which successfully compensates for the threshold voltage variations in poly-Si thin-film transitors (TFTs), is proposed, and verified by SPICE simulation and experiments. In order to compensate for variations in OLED current, the proposed pixel design employs a new voltage modulation scheme using diode connections. 相似文献
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This work demonstrates the feasibility of a novel pixel circuit by using three a-Si:H TFTs. The proposed circuit can stabilize the OLED current and provide an additional driving current to ameliorate the brightness degradation of the AMOLED. Measurement results indicate that the current degradation of the proposed circuit, caused by VTH variations, is less than 5% over more than 50,000 s at 60 °C, whereas that of a conventional 2T1C pixel circuit is larger than 34%. Furthermore, to ameliorate the decrease in luminance owing to the OLED degradation, the OLED current can be increased by 10% by analyzing the current degradation and modulating the detected voltage appropriately. 相似文献
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A new a-Si:H TFT pixel circuit compensating the threshold voltage shift of a-Si:H TFT and OLED for active matrix OLED 总被引:1,自引:0,他引:1
Jae-Hoon Lee Ji-Hoon Kim Min-Koo Han 《Electron Device Letters, IEEE》2005,26(12):897-899
We propose a new hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) pixel circuit for an active matrix organic light-emitting diode (AMOLED) employing a voltage programming. The proposed a-Si:H TFT pixel circuit, which consists of five switching TFTs, one driving TFT, and one capacitor, successfully minimizes a decrease of OLED current caused by threshold voltage degradation of a-Si:H TFT and OLED. Our experimental results, based on the bias-temperature stress, exhibit that the output current for OLED is decreased by 7% in the proposed pixel, while it is decreased by 28% in the conventional 2-TFT pixel. 相似文献
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Ya-Hsiang Tai Bo-Ting Chen Yu-Ju Kuo Chun-Chien Tsai Ko-Yu Chiang Ying-Jyun Wei Huang-Chung Cheng 《Display Technology, Journal of》2005,1(1):100-104
A new pixel circuit design for active matrix organic light-emitting diode (AMOLED), based on the low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) is proposed and verified by SPICE simulation. Threshold voltage compensation pixel circuit consisting of four n-type TFTs, one p-type TFT, one additional control signal, and one storage capacitor is used to enhance display image quality. The simulation results show that this pixel circuit has high immunity to the variation of poly-Si TFT characteristics. 相似文献