我国全线打通AMOLED制造工艺技术

日前,记者从有关方面获悉,昆山工研院新型平板显示技术中心（简称昆山平板显示中心）和维信诺公司在国内率先全线打通了LTPS—TFT背板和OLED显示屏制造工艺技术,并于2010年12月24日,     

OLED最新动态

一、我国全线打通AMOLEDfN造工艺技术日前．从有关方面获悉．昆山工研院新型平板显示技术中心（简称昆山平板显示中心）和维信诺公司在国内率先全线打通了LTPS—TFT背板和OLED显示屏制造工艺技术．     

低温多晶硅TFT技术的发展

本文综述低温多晶硅（LTPS）TFT技术的最新进展情况。该技术目前的研究前沿是：（1）制作高性能的TFT；（2）在柔性衬底上制作LTPS TFT；（3）驱动有机发光器件的TFT；（4）LTPS TFT的新应用。同时还展望了LTPS TFT技术的未来发展趋势。     

京东方推出大尺寸氧化物OLED显示屏

近日,国内显示领域领军企业——京东方科技集团成功研发出17英寸AMOLED彩色显示屏,这是全球首款融合了氧化物TFT背板技术和喷墨打印技术的大尺寸AMOLED显示屏。同期,国内首款17英寸利用氧化物TFT和真空蒸镀技术制备的AMOLED显示屏,也在京东方问世。这是继今年年初发布国内首款氧化物TFT液晶显示屏后,仅半年时间里,京东方在新型显示领域取得的又一重大进展。     

非晶铟镓锌氧薄膜晶体管银/钛源漏电极的研究

为了适应大尺寸高分辨率显示的技术需求,研究并开发用于非晶铟镓锌氧(a-IGZO)薄膜晶体管(TFT)阵列的低电阻电极非常关键。本文采用磁控溅射制备的金属银为源漏电极,设计并制作了底栅结构的a-IGZO TFT器件。实验发现,具有单层银源漏电极的器件电学特性较差,这是因为银与a-IGZO之间不能形成良好的欧姆接触。另一方面,通过增加钛中间层而形成的Ag/Ti电极在保持低电阻的同时能够有效阻止银原子扩散并与a-IGZO形成较好的接触状态。最终制备的以Ag/Ti为源漏电极的a-IGZO TFT具有明显改善的电学特性,场效应迁移率为1.73cm~2/V·s,亚阈值摆幅2.8V/(°),开关比为2×10~7,由此证明了磁控溅射制备的银电极具有应用于非晶氧化物薄膜晶体管的实际潜力。     

面板厂商展开利用非晶硅技术生产高分辨率智能手机面板的战略

正随着高分辨率智能手机时代的来临,降低耗电是生产平面显示器的关键。传统意义上来讲,非晶硅薄膜晶体管液晶显示(a-Si TFT LCD)技术不能有效降低电量损耗,因此面板厂商不得不考虑使用低温多晶硅(LTPS)和氧化物(oxide)技术来制造高分辨率面板。NPD DisplaySearch表示,LTPS(低温多晶硅)和Oxide(金属氧化物半导体)面板有较高的电子迁移率,所以即使达     

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...     

基于IGZO的5.5 in FHD In-cell触控FFS面板设计

为了达到便携移动终端日益轻薄的要求,In-cell Touch技术是触控的最佳选择。目前,非晶铟镓锌氧化物薄膜晶体管(a-IGZO TFT)越来越受到人们的关注,与传统的硅基TFT相比,IGZO拥有其相应的优势,并且制造成本较LTPS TFT低廉,制备过程容易掌控。为了将IGZO材料的优点运用在触控显示面板上,设计了一款5.5in FHD In-cell Touch面板。为了实现FHD的分辨率,首次采用IGZO-TFT模型设计多工器(MUX),并用它驱动本文所述的面板。通过检测,触控的信噪比达54dB以上。在文章最后展示了基于此次设计成功做出的样机。本文对实现自容式多点in-cell触控的关键结构做了简单的介绍,针对在试做过程中遇到的寄生电容问题做了详细的分析,并描述了相应的解决方法。将IGZO技术与In-cell Touch技术融合,能够在较简单的工艺下达到高规格触控面板的需求。     

大尺寸AMOLED HDTV的可选方案

本文提出了目前大尺寸AMOLED制造技术的可选方案,例如：多晶硅TFT制造的非激光结晶方法以及采用激光感应热成像（LITI）的彩色图像成型。特别是,已经得出超大晶粒结晶（SGS）方法在灵活性及无电流方面获得了高性能TFT。对于此类大尺寸AMOLED技术的可行性,我们用17英寸UXGA AMOLED显示器进行了演示,其结果显示出了良好的亮度一致性。     

美国制造出世界上最大尺寸OLED柔性显示器

近日,美国亚利桑那大学柔性电子与显示中心（FEDC）利用混合氧化物薄膜晶体管（TFT）成功制造出了世界上最大尺寸的OLED彩色柔性显示器样机。该显示器由柔性电子与显示中心与美国陆军研究实验室联合开发,尺寸为14．7英寸,达到了该中心此前创造世界纪录型号的两倍。     

Polysilicon thin-film transistors on polymer substrates

Different approaches to fabricate low-temperature polycrystalline silicon (LTPS) thin film transistors (TFTs) on polymer substrates are reviewed and the two main routes are discussed: (1) standard fabrication of LTPS TFTs on glass substrates followed by a transfer process of the devices on the polymeric substrate; (2) direct fabrication of the devices on the polymeric substrate. Among the different techniques we have described in more detail the process we have recently developed for the fabrication of LTPS TFTs directly on ultra-thin polyimide (PI) substrate. LTPS TFT technology is particularly suited for high performance flexible electronics applications, due to the excellent device characteristics, good electrical stability and CMOS technology. Flexible display application remains the most attractive application for LTPS technology, especially for AMOLED displays, where device stability and the possibility to integrate the driving circuits make LTPS technology superior to all the other competitive TFT technologies. Among the other applications, particularly promising is also the application to flexible smart sensors, where integration of a front-end electronics is essential. Some examples of flexible gas sensors and pressure sensors, integrated with simple readout electronics based on LTPS TFTs and fabricated on ultra-thin PI substrate, are presented.     

基于 P-Type 多晶硅TFT技术的集成型有源 OLED 驱动电路

低温多晶硅(LTPS:Low-temperature poly-Si)技术已经成为薄膜晶体管(TFT:thin film transistor)制作中最具吸引力的技术,并应用在AMOLED显示器中.P-type 技术能够简化 TFT 的制作过程.本文提出了一种应用 p-type 多晶硅 TFT的 AMOLED 驱动电路结构,包括栅极驱动器、数据驱动器以及像素阵列.数据驱动器采用分块方法,使得显示屏的输出线数大大减少.作者采用一种改进的 p-type 移位寄存器实现逐行选通的功能,并采用由 4 个 p-type 反相器级联构成的缓冲器来提高电路的驱动能力.为了验证上述电路结构的正确性,作者采用 HSPICE 软件进行仿真分析.结果表明,电路工作正常.利用韩国汉城国立大学及 Neo Poly 公司在多晶硅制作方面的优势,我们已经合作完成了应用上述电路结构的分辨率为96×3×128的有源 OLED 的制作.     

An integrated driving circuit implemented with p-type LTPS TFTs for AMOLED

Based on the technology of low temperature poly silicon thin film transistors (poly-Si-TFTs), a novel p-type TFT AMOLED panel with self-scanned driving circuit is introduced in this paper. A shift register formed with novel p-type TFTs is pro- posed to realize the gate driver. A flip-latch cooperated with the shift register is designed to conduct the data writing. In order to verify the validity of the proposed design, the circuits are simulated with SILVACO TCAD tools, using the MODEL in which the paramete...     

Driving schemes for a-Si and LTPS AMOLED displays

Design of stable active matrix organic light-emitting diode (AMOLED) displays comes with significant challenges that stem from the electrical property of the backplane materials, line parasitics in the matrix, and the opto-electronic property of the organic light-emitting diode (OLED). This paper reviews voltage and current programming schemes for AMOLEDs. Following a systematic review of pixel circuits, design considerations are examined for both current and voltage schemes with focus on stability and programming speed for both amorphous silicon (a-Si) and low temperature polysilicon (LTPS) pixel circuits. In particular, spatial parameter variations and stability, which hinder reliable operation of AMOLED display backplanes, are discussed. Analysis shows that while driving schemes reported hitherto maybe suitable for small and medium size displays, new schemes are critically needed for large-area high-resolution AMOLED displays.     

A Novel Voltage-Feedback Pixel Circuit for AMOLED Displays

This study presents a novel voltage-modulated pixel circuit for active-matrix organic light-emitting diode (AMOLED) consisting of five n-type thin-film transistors (TFTs), one additional control signal, and one storage capacitor. The proposed circuit, which can be implemented in all-n-type and all-p-type low temperature poly-silicon (LTPS) TFT technologies, successfully compensates for threshold voltage deviation of TFTs and facilitates correction of OLED degradation using a voltage feedback method. Simulation and experimental results for all-n-type TFTs indicate that the proposed pixel circuit reduced the nonuniformity brightness problem effectively by compensating for threshold voltage variation in TFTs and reduced the degradation of emission efficiency in OLEDs.     

Enhancement of Brightness Uniformity by a New Voltage-Modulated Pixel Design for AMOLED Displays

This letter presents a new pixel design and driving method for active-matrix organic light-emitting diode (AMOLED) displays using low-temperature polycrystalline silicon thin-film transistors (TFTs). The proposed pixel circuit consists of five TFTs and one capacitor to eliminate the variation in the threshold voltage of the TFTs, and the drop in the supply voltage in a single frame operation by the source-follower-type connection and the bootstrap. The proposed pixel circuit has been verified to realize uniform output current by the simulation work using the HSPICE software. The novel pixel design has great potential for use in large-size and high-resolution AMOLED displays.     

Electrical characteristics of a-IGZO transistors along the in-plane axis during outward bending

A highly flexible amorphous indium–gallium–zinc–oxide (a-IGZO) thin film transistor (TFT) was tested with respect to the in-plane axis location and device architecture in a bending system. Short channel a-IGZO TFTs were fabricated based on the conventional coplanar configuration and the islanded structure on a polyimide (PI) substrate and were then subjected to a cyclic bending of 1 × 10⁵ with varying radii smaller than a few mm. Embedding the devices at a neutral position in bending system allowed them to function well when exposed to the induced mechanical strain, regardless of the difference in the structural geometry. However, placement of the TFTs outside of the neutral surface resulted in a drastic suppression of the strain-induced electrical failure for the island configuration as the distance of the TFTs from the neutral surface increased. By contrast, the conventional structure, when placed outside the neutral surface, showed strongly accelerated device failure as the strain on the TFTs was increased. The electromechanical integrity was maintained for island-structured TFTs under a bending stress with a radius of 1 mm and a position margin of 50 μm away from the neutral surface. The brittle and rigid characteristics of TFT arrays with inorganic components are still considered problematic in terms of being put into practical use in flexible applications; nevertheless, the high flexibility achieved by this structural design and its geometrical characterization along the in-plane axis shows the great potential for a-IGZO TFTs to serve as the functional building blocks of new platform applications, such as rolling or folding displays, by suppressing the mechanical strain in the backplane.     

Analysis of Negative Bias Temperature Instability in Body-Tied Low-Temperature Polycrystalline Silicon Thin-Film Transistors

Negative bias temperature instability (NBTI) degradation mechanism in body-tied low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) is analyzed by the charge-pumping (CP) technique. The properties of bulk trap states (including interface and grain boundary trap states) are directly characterized from the CP current. The increase of the fixed oxide charges is also extracted, which has not been quantified in previous studies of NBTI degradation in LTPS TFTs. The experimental results confirm that the NBTI degradation in LTPS TFTs is caused by the generation of bulk trap states and oxide trap states.     

柔性AMOLED的技术现状与进展

目前已经有商业化的AMOLED产品应用在MP3、手机上,而采用柔性基板的AMOLED也正在研制中,但真正实现商业化还面临诸多技术难题,如柔性衬底处理技术,柔性基板的TFT制备方法,有机薄膜蒸镀和薄膜封装等。具体分析了相关问题的处理方法和技术现状。指出使用塑胶衬底,开展有机氧化物TFT制备的发展思路。提示我国在有机薄膜蒸镀和薄膜封装领域有较大的潜在机会。     

高可靠性Cu BCE a-IGZO TFTs的制作

背沟道刻蚀型（BCE）非晶氧化铟镓锌薄膜晶体管（a-IGZO TFT）具有工艺简单、寄生电容小以及开口率高等优点,但BCE IGZO器件背沟道易受酸液和等离子体损伤,进而引起TFT均匀性和稳定性等方面问题,随着GOA技术的导入,对TFT器件电学性能的均匀性和稳定性提升的要求也日益迫切,因此开发高信赖性BCE IGZO TFT是技术和市场的迫切要求。本文主要分析了基于IGZO的背沟道刻蚀型薄膜晶体管电学性质,通过优化钝化层材料,色阻材料以及GOA TFT结构等削弱因背沟道水汽吸附引起的器件劣化,偏压温度应力测试结果显示优化后的TFT展现了良好的稳定性——在80℃,栅极30 V负向偏压条件下,2 000 s的ΔV_th小于1 V。最终,利用优化的IGZO TFT制作了215.9 mm（85 in）8K4K 120 Hz液晶显示器。