具有顶部发光结构的AMOLED交流驱动电路

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.     

一种基于低温多晶硅薄膜晶体管的交流AMOLED像素补偿电路

This paper presents a new poly-Si pixel circuit employing AC driving mode for active matrix organic light-emitting diode （AMOLED） displays. The proposed pixel circuit, which consists of one driving thin-film tran- sistor （TFT）, three switching TFTs, and one storage capacitor, can effectively compensate for the threshold voltage variation in poly-Si and the OLED degradation. As there is no light emission, except for during the emitting period, and a small number of devices used in the proposed pixel circuit, a high contrast ratio and a high pixel aperture ratio can be easily achieved. Simulation results by SMART-SPICE software show that the non-uniformity of the OLED current for the proposed pixel circuit is significantly decreased （〈 10%） with an average value of 2.63%, while that of the conventional 2T1C is 103%. Thus the brightness uniformity of AMOLED displays can be improved by using the proposed pixel circuit.     

利用热丝化学气相沉积制备外延生长多晶硅薄膜

Polycrystalline silicon(poly-Si) films were prepared by hot-wire chemical vapor deposition(HWCVD)at a low substrate temperature of 525 ℃. The influence of hydrogen on the epitaxial growth of ploy-Si films was investigated. Raman spectra show that the poly-Si films are fully crystallized at 525 ℃ with a different hydrogen dilution ratio(50%–91.7%). X-ray diffraction, grazing incidence X-ray diffraction and SEM images show that the poly-Si thin films present(100) preferred orientation on(100) c-Si substrate in the high hydrogen dilution condition.The P-type poly-Si film prepared with a hydrogen dilution ratio of 91.7% shows a hall mobility of 8.78 cm2/(V·s)with a carrier concentration of 1.3×1020 cm-3, which indicates that the epitaxial poly-Si film prepared by HWCVD has the possibility to be used in photovoltaic and TFT devices.     

几种电流型AMOLED像素电路及其电流缩放比的分析

分析了4种典型的电流型AM OLED像素驱动电路的工作原理,从中总结出了补偿阈值电压漂移的方法--自动调节存储电容的电压以保证电流不变.着重提出了电流缩放比的定义,对传统结构、电流镜结构、分压结构和电容耦合结构这4种电流型AM OLED像素驱动电路的电流缩放比进行了比较和分析.在这4种电路中,电流缩放比依次增大,显示出电流型像素电路在解决电容充电时间问题上的进步与完善.     

一种新的有源OLED交流驱动电路

在电流编程像素电路的基础上提出了一种新的交流驱动电路结构.该电路结构不仅能实现OLED的交流驱动,而且能避免由于制作过程的变化和长时间的工作引起的驱动管阈值电压漂移的现象,这种现象将导致OLED显示屏的亮度不一致.另外这种驱动方式还能消除在反偏脉冲起始和结束时刻的尖峰电流.最后,用AIM-SPICE软件对电路进行了仿真,仿真结果表明OLED器件在恢复时间内处于反偏状态.     

具有容错功能的OLED有源驱动电路

以有机电致发光器件(OLED)为基础的显示或照明器件,通常会受到短路故障的影响,从而使得像素失效,降低面板的亮度,进而严重地影响亮度的均匀性,并且会产生大量的功耗.本文介绍了一种新的有源OLED驱动电路,以自动检测在OLED中发生的短路故障并切换至备用OLED.该电路采用p型低温多晶硅薄膜晶体管制造.当发生短路故障时,本电路可以在不改变驱动电流的情况下,保持OLED像素的亮度维持不变.实验结果表明,本电路不仅具有容错功能,而且与标准电路相比可以显著地降低功耗.     

基于低温多晶硅-氧化物半导体混合集成的薄膜晶体管显示背板技术

低温多晶硅-氧化物半导体混合集成(Low temperature polycrystalline silicon and oxide,LTPO)的薄膜晶体管(thin-film transistor,TFT)背板技术融合了低温多晶硅和氧化物半导体TFT两者的优势,为低功耗、高性能显示以及功能化集成提供了新的发展机遇,获...     

热退火对多晶硅特性的影响

为研究热退火对太阳电池用多晶硅的影响,在750～1150℃,N2和O2环境下分别对硅片进行热处理.用傅里叶红外光谱仪和准稳态光电导衰减法测量退火前后的氧碳含量和少子寿命的变化.为了比较,对有相同氧碳含量的直拉硅片进行同样处理.结果发现:在多晶和单晶片中氧碳含量下降很小,意味着没有氧沉淀产生,晶界对碳行为影响不大.多晶硅片在N2和O2环境下,850、950和1150℃下退火,少子寿命都有很大提高,并且在O2中退火比N2中退火少子寿命上升得更多,可能由于在高温退火时大量杂质扩散到晶界处,减少了复合中心.另外,间隙硅原子填充了空位或复合中心从而导致寿命提高.     

一种LTPS-TFT AMOLED像素电路的理论研究

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。     

125mm彩色AMOLED的多晶硅TFT基板

用化学法在非晶硅表面形成Ni源,经金属诱导晶化(MIC)得到了大晶粒碟型多晶硅.为改善以此材料作有源层的多晶硅TFT的漏电特性和均匀性,采用动态杂质吸除方法对MIC 过程所残留的Ni进行了吸除.通过流程简化,采用6块版工艺,研制出125mm QVGA有源选址有机发光显示的多晶硅TFT选址矩阵基板.     

125mm彩色AMOLED的多晶硅TFT基板

用化学法在非晶硅表面形成Ni源，经金属诱导晶化（MIC）得到了大晶粒碟型多晶硅. 为改善以此材料作有源层的多晶硅TFT的漏电特性和均匀性，采用动态杂质吸除方法对MIC 过程所残留的Ni进行了吸除. 通过流程简化，采用6块版工艺，研制出125mm QVGA有源选址有机发光显示的多晶硅TFT选址矩阵基板.     

一种新的应用到硅基有机发光二极管微显示像素电路仿真的OLED SPICE模型

本文介绍了一种新的OLED器件等效电路模型。由于单二极管模型能和多二极管模型一样较好的模拟OLED特性,因此新模型是基于单二极管模型建立的。并且为了保证拟合数据和测试数据有很好的一致性,在新模型中将常量电阻替换成指数电阻。通过与测试数据和其他两种OLED SPICE模型的模拟数据对比,新的模型更符合OLED的电流电压特性。新的模型能直接整合到SPICE电路仿真器中去,并且在OLED整个电压工作范围内拥有较好的仿真精度。     

用于有机发光二极管的具有开关漏电抑制能力的像素电路

本文介绍了一种用于有机发光二极管微显示系统的像素电路,该电路具有开关漏电抑制能力。在信号保持期间,电路采用无外部输入的自参考环路跟踪内部节点电压,达到漏电抑制的目的。采用该漏电抑制技术可以用更小的存储电容获得更长的保持时间。采用0.35-μm CMOS 工艺实现了一个60×80像素阵列的试验系统,像素面积是15×15 μm^2。测试结果表明,本文提出的像素电路获得了超过500ms的保持时间,在100pA~3nA输出电流范围内获得了良好的精度和线性度。     

High-speed low-power voltage-programmed driving scheme for AMOLED displays

A new voltage-programmed driving scheme named the mixed parallel addressing scheme is presented for AMOLED displays, in which one compensation interval can be divided into the first compensation frame and the consequent N-1 post-compensation frames without periods of initialization and threshold voltage detection. The proposed driving scheme has the advantages of both high speed and low driving power due to the mixture of the pipeline technology and the threshold voltage one-time detection technology. Corresponding to the proposed driving scheme, we also propose a new voltage-programmed compensation pixel circuit, which consists of five TFTs and two capacitors(5T2C). In-Zn-O thin-film transistors(IZO TFTs) are used to build the proposed 5T2C pixel circuit. It is shown that the non-uniformity of the proposed pixel circuit is considerably reduced compared with that of the conventional 2T1C pixel circuit. The number of frames(N) preserved in the proposed driving scheme are measured and can be up to 35 with the variation of the OLED current remaining in an acceptable range. Moreover, the proposed voltage-programmed driving scheme can be more valuable for an AMOLED display with high resolution, and may also be applied to other compensation pixel circuits.     

有源OLED像素电路的设计与仿真

设计了有源OLED显示用非晶硅薄膜晶体管恒流型4-TFT像素驱动电路，并给出了驱动方法。应用HSPICE仿真了恒流型像素驱动电路的工作过程，详细分析了源（Source）电压VDD、存储电容Cs，以及开关晶体管T1、驱动晶体管T3的宽长比等参数对电路的输出特性的影响。仿真结果表明，此电路可以在整个帧周期持续供给OLED器件电流，并且解决了由于各像素驱动管阈值电压的差异带来的OLED亮度的不均匀问题。     

AMOLED像素电路的设计与仿真研究

为了解决驱动管阈值电压漂移带来的OLED亮度不均匀的问题,介绍了一种新的AMOLED四管像素电路,利用HSPICE仿真软件详细分析了电路各参数对其输出特性的影响,同时给出了参数设计的方法.最后从延长OLED的使用寿命出发,对电路进行了改进并根据已设计的参数进行了仿真,结果表明改进后的电路功能不变,且在驱动阶段,驱动电流...