Polysilicon TFT technology for active matrix OLED displays

The integration of active matrix polysilicon TFT technology with organic light emitting diode (OLED) displays has been investigated with the goal of producing displays of uniform brightness. This work identifies and addresses several process integration issues unique to this type of display which are important in achieving bright and uniform displays. Rapid thermal processing has been incorporated to achieve uniform polysilicon microstructure, along with silicides to reduce parasitic source and drain series resistance. Using these processes, TFT drain current nonuniformity has been reduced below 5% for 90% of the devices. This work also introduces transition metals to produce low resistance contacts to ITO and to eliminate hillock formation in the aluminum metallization. These processes, along with spin on glasses for planarization, have been used to produce functional active matrix arrays for OLED displays. The final array pixel performance is also presented     

Flexible AM OLED panel driven by bottom-contact OTFTs

Active matrix organic-light-emitting-diode (AM OLED) panels, driven by organic thin-film transistors (OTFT), have been successfully fabricated on a flexible plastic substrate. The pixel circuit consists of two bottom-contact pentacene OTFTs working as switching and driving transistors. The panel has 16 /spl times/ 16 pixels, each of which have an OLED using a phosphorescent material with an emission efficiency of 30 cd/A. A tantalum oxide (Ta/sub 2/O/sub 5/) film with a dielectric constant of 24, prepared by the anodization of Tantalum (Ta), was used as the gate insulator of the OTFTs. The passivation layer on the OTFTs was formed by a layer of silicon dioxide (SiO/sub 2/) and two layers of polyvinyl alcohol. Using OTFTs with a Ta/sub 2/O/sub 5/ gate insulator, the authors have realized a flexible active matrix OLED panel driven with a low voltage of -12 V.     

并五苯薄膜晶体管及其应用

有机薄膜晶体管(TFT)在数据存储、集成电路、传感器诸方面的广泛应用引起了人们极大的兴趣.在有机TFT的研究中,并五苯TFT占有很重要的地位.介绍了并五苯薄膜晶体管的结构、工作原理及其应用,评述了该领域的研究进展,并对其前景进行了展望.     

AM OLED:OLED的"明日之星"

本文对近期平板显示市场的一些变化,如液晶的大幅降价对PMOLED(被动式OLED)的冲击,AMOLED(主动式OLED)的最新变化及技术趋势进行了概括分析.     

基于HD66773的TFT OLED驱动电路的设计

介绍了用驱动TFT LCD的HD66773芯片驱动5cm(2in)TFT OLED的电路设计．通过对芯片做出合理的特殊设置,最终可以显示出8种颜色,达到初步点亮TFT OLED的目的．并给出了初始化软件流程和MCU接口。     

采用简化多晶硅TFT工艺的有源矩阵OLED显示器件

我们提出并开发了一种先进的6步光掩模工艺,可用于制备有源矩阵有机发光二极管(AMOLED)中p型沟道多晶硅薄膜晶体管(TFT)面板。通过去除电源线(Vdd)和触排(bank)光处理工艺,将8步掩模简化至6步。通过6步光掩模工艺制备的p型沟道TFT,场效应迁移率可达80cm2/Vsec,亚阈值(sub-threshold)电压波动降至0.3V/dec,阈值电压约为-2V。利用6步光掩模工艺成功地获得了采用电压驱动方式的7英寸WVGA(720×480)AMOLED面板。     

蓝色磷光OLED可以改善平面显示器

有机发光器件(OLED)制造商,Universal Display公司(位于新泽西州的Ewing),和它的研究合作伙伴普林斯顿大学(位于新泽西州的Princeton),和南加州大学(位于加州的Los Angeles),成功地开发出来了蓝色磷光OLED。据称这是世界上第一次开发出效率比较高的蓝色磷光OLED。这种器件,与已经开发成功的红色,绿色磷光OLED器件一     

A new a-Si:H TFT pixel circuit compensating the threshold voltage shift of a-Si:H TFT and OLED for active matrix OLED

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.     

Pentacene TFT with improved linear region characteristics usingchemically modified source and drain electrodes

We have fabricated pentacene active layer organic thin film transistors (OTFTs) using chemically-modified source and drain contacts with improved contact and linear region characteristics. OTFTs fabricated on heavily doped, thermally oxidized single-crystal silicon substrates have linear field-effect mobility greater than 0.5 cm² /V-s at a drain-source voltage of -0.1 V, on/off current ratio greater than 10⁷, and subthreshold slope as low as 0.7 V/decade     

a-Si：H TFT OLED驱动电路中存储电容对显示性能的影响

对OLED两管a-Si: H有源驱动技术中存储电容对器件寿命的影响进行了详细的讨论;结合驱动管的宽长比,从理论分析和SPICE模拟两个方面研究了存储电容对电路充电率、跳变电压和保持特性的影响,找出其间相互制约的数量关系,最后给出优化设计的参考值.     

Two mask step polysilicon TFT technology for flat panel displays

The deep relationship between MDS codes and threshold schemes in cryptography is initially reported in this paper. It is found that by using the generation matrices or the parity check matrices, MDS codes, one can implement a new class of threshold systems in cryptography     

Design aspects of low power polymer/OLED passive-matrix displays

Polymer and small molecule organic LED technologies offer many attractive properties for use in a display. The highly efficient light generation at low supply voltages and the limited thickness of the display are advantageous for mobile applications. Furthermore, the large viewing angle, high contrast and fast switching speed give excellent picture quality for text and video mode operation.Optimal uniformity of the passive-matrix display is achieved with current-driven operation. This reduces the influence of material degradation as well as voltage drops across the connection leads. Amplitude and pulse width modulation can be used to obtain grey levels.This presentation discusses design aspects of small-size, full-colour passive-driven polymer LED matrix displays. Consequences of multiplexing, colour sub-pixelation, aperture and display parasitics are analysed and requirements for the RGB materials are formulated to obtain low power dissipation of the module.The efficiency of red polymers, that are available up to now, is too low. This leads to an unbalanced current density in comparison with green and blue which is unfavourable for the display power consumption.     

a-Si TFT OLED有源驱动阵列参数的优化与布图设计

主要介绍了用于有源驱动有机发光二极管显示屏的非晶硅薄膜晶体管阵列中各种电子器件参数的设计依据，通过理论计算，确定了单元像素中的各种器件参数；利用Aim-spice进行模拟仿真，对器件的参数进行了优化；利用L-Edit进行布图设计，完成了阵列像素的版图。该设计对小尺寸非晶硅有源驱动OLED的研究开发有一定的意义。     

用于OLED的a-Si TFT有源驱动阵列保护电路的分析

在模拟与仿真的基础上．根据MOS器件的源漏击穿特性．分析了用于a-Si TFT有源驱动阵列的外围保护电路的工作原理;同时根据所采用的有源OLED单元像素驱动电路的特点,确定了电源线、数据线、信号线上的相应保护电路形式。该保护电路可应用于OLED的有源驱动TFT阵列。     

ITO/AINdN/Al contact process for active matrix OLED displays

Integrating circuits into organic light emitting diode displays requires fabrication of polycrystalline silicon (poly-Si) based thin-film transistors (TFTs) on glass substrates. A novel ITO/AlNdN/Al contact process has been developed for the pixel step. In metallisation, ITO/Al interconnection is metallurgically undesirable. An AlNdN layer is selected for a pixel material and ITO/AlNdN/Al structure is applied to the pixel line. Reported is the feasibility for the multilevel ITO/AlNdN/Al contact, which can make the poly-Si TFTs competitive in the market.     

A Novel LTPS-TFT Pixel Circuit Compensating for TFT Threshold-Voltage Shift and OLED Degradation for AMOLED

This letter presents a novel pixel circuit that uses low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs) composed of one driving and four switching TFTs for active-matrix organic light-emitting diodes (AMOLEDs) with a voltage-source method. The proposed circuit effectively enables threshold-voltage-shift correction of the drive TFT and compensates for degradation of the OLED using a feedback structure     

OLED显示器的SMBus接口软硬件实现

随着时代发展,户外使用的手持设备越来越多,这就需要一款工作温度范围宽,抗日晒的显示器。新兴OLED显示器家族不但价格低廉、重量轻、体积小,而且具有LCD显示器不具备的宽温特点,必将占据未来的市场。就OLED显示器的软、硬件实现方法提出了方案,并给出电路和软件,以供参考使用。这种应用方式,普遍适用于OLED显示器的设计。     

一种基于HSV色彩空间的OLED低功耗方法

为了降低有机发光器件(OLED)的功耗,同时又保证显示图像的质量,提出一种基于色调、 饱和度和亮度(HSV,hue,saturation and value)色彩空 间的OLED低功耗方法。通过整合亮度调节(VS)和 饱和度调节(SS)降低显示图像的功耗,应用感兴趣区域(ROI,region of interest) 到图像边界逐级调节技术提升 图像质量,采用平均结构相似度指数(MSSIM,mean structu ral similarity index)对原始输入图像和输出图像在亮度、对比度和结构相似性上进行比 较以评价图像相似程度,达到 保持较高图像质量的同时降低功耗的目的。实验结果表明,图像渐变级数level为15时, 本文提出的亮度与饱和度整合调节(VSI)方法在保持图像的ROI具有80.31%的相似度的同时节省了57.93%的OLED功耗。     

Improved a-Si:H TFT pixel electrode circuits for active-matrixorganic light emitting displays

Two improved four thin-film-transistors (TFTs) pixel electrode circuits based on hydrogenated amorphous silicon (a-Si:H) technology have been designed. Both circuits can provide a constant output current level and can be automatically adjusted for TFT threshold voltage variations. The circuit simulation results indicate that an excellent linearity between the output current and input current can be established. An output current level higher than ~5 μA can be achieved with these circuits. This current level can provide a pixel electrode brightness higher than 1000 cd/m² with the organic light-emitting device (OLED) having an external quantum efficiency of 1%. These pixel electrode circuits can potentially be used for the active-matrix organic light-emitting displays (AM-OLEDs)     

大尺寸高分辨率AM OLED的激光热转印技术

激光热转印(Laser Induced'rhermal Imaging,LITI)是1种新型全彩色AM oLED像素图形制造技术.LITI技术有很多独特的优点,如转印的薄膜厚度均匀,具有多层薄膜叠加转印能力,分辨率高以及易于在大尺寸基板上生产等.韩国三星SDI研究开发中心的研究人员研发并优化了LITI技术制备小分子OLED的各项工艺.所制得的器件具有优异的稳定性.采用LITI技术制造的2.0"QVGA OLED显示器在150 cd/m2白光亮度下,工作寿命超过了20 000 h.研究人员还建立了1条基于第4代基板的LITI OLED中试生产线,为大规模生产LITI OLED做先导研究.