OLED有源驱动TFT阵列的一种测试方法

提出了一种检测有源驱动OLED TFT阵列的方法,这种电流检测方法是结合TFT的制作工艺进行的.在只增加一块光刻版的情况下,有效地解决了在含有2个TFT的单元像素电路中,检测驱动管困难的难题.这种检测方法能够进行快速的全屏检测,具有精度高,对TFT阵列无损伤的特点.     

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。     

投影电视液晶显示组件

一、LCD组件的结构图1和图2分别示出松下公司研制的TFT—LCD的剖面图及非晶硅薄膜晶体管阵列的显微镜照片。 a-Si TFT阵列在56.6×42.7mm~2的显示面积内以节距89(高)×87(宽)μm~2形成了480×650象素。这种a-Si TFT阵列可用5次光刻制作而成。     

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.     

新技术"通过鉴定"后的悲哀

由西北工业大学航空微电子中心研制的、名为龙腾T1芯片的手机用TFT彩色液晶显示驱动控制电路芯片,日前通过陕西省科技厅组织的成果鉴定.这种芯片是国内首家研发成功具有完全自主知识产权的我国首款手机用TFT彩色液晶显示驱动芯片.     

大屏幕TFT液晶显示器栅极/源极显示驱动解决方案

本文首先对TFT液晶显示技术进行了简要的介绍,随后对大屏幕TFT液晶栅极/源极显示驱动技术进行了详细的解析,最后对典型的大屏幕TFT液晶显示系统给出了完整的栅极/源极显示驱动芯片解决方案.     

TFT基板低功耗显示驱动方法研究

TFT的低功耗特性能够减少电子设备的能量消耗，从而达到节省能源、延长电池寿命、降低使用设备温度、提高显示质量的目的。因此，低功耗TFT在电子设备的设计和制造中具有十分重要的作用。TFT基板的结构有很多种类，通常可分为一般型、高温多晶硅型、低温多晶硅型、金属氧化物半导体型和柔性材料基板型。本文对现有的TFT基板显示器件的低功耗研究进行总结分析，主要包括两大方面：对TFT基板本身驱动进行优化；对TFT基板外设驱动进行优化。本文对两大方面的低功耗研究进行了综述，并对近年来国内外TFT低功耗方法研究进行详细介绍。根据所介绍的方法的特点与其尚未攻克的困境，对TFT基板显示设备低功耗驱动的未来发展进行了展望。     

新书推荐——薄膜晶体管（TFT）阵列制造技术

本书主要介绍非晶硅（amorphous silicon，a-Si）TFT阵列大规模生产的制造技术，共13章，内容从TFT元件的结构及特点，到TFT的检查与修复，包括TFT阵列制造清洗工艺、成膜工艺、光刻工艺、不尉辑析和检查修复。本书从11可阵列大规模制造的角度，第一次比较全面地介绍了TFT LCD牛产线的TFT阵列制造工艺技术、工艺参数、生产工艺技术管理、工艺材料规格、设备特性、     

TFT阵列工艺简化

三星电子成功开发了3套掩模版TFT阵列工艺技术。一般TFT阵列工艺采用5或4套掩模版技术制作TFT阵列，3套掩模版工艺与4套掩模版工艺相比较，缩短工序，降低生产成本，生产能力提高20％，将增强企业的竞争力。     

a-Si:H-TFT阈值电压漂移机理及其在驱动OLED显示中的补偿设计

分析了a—Si：H—TFT阈值电压漂移的机理，即分析了栅偏应力下电荷注入到SiNx：H栅绝缘层和a—Si：H中亚稳态的产生对TFT阈值电压漂移的影响。根据非晶硅中亚稳态产生的特点，并针对驱动OLED的两管a—Si：H—TFT像素电路，提出了一种通过对数据信号时序的重新设计来补偿周值电压漂移的方法，即在数据信号间加插一个与数据信号极性相反的补偿信号。通过这种正负交替的信号，使驱动管TFT中由亚稳态造成的阈值电压漂移始终保持在一个动态平衡的过程，来实现驱动OLED电流稳定的目的。     

一种驱动MOS管工作在饱和区的硅基OLED微显示像素电路

硅基OLED微显示中为了在极小的像素面积内实现微小的OLED工作电流,其像素驱动电路的驱动MOS管一般工作在亚阈值区,存在OLED电流对驱动MOS管的阈值电压和栅源电压失配敏感、外围电路复杂等问题,如果驱动MOS管工作在饱和区则可避免这些问题,但为了获得微小的驱动电流,必须采用尺寸大的倒比MOS管,这又与极小的像素面积冲突。本文提出了一种采用脉宽调制(PWM)技术、驱动MOS管工作在饱和区的OLED微显示像素驱动电路,PWM信号减少了一帧内OLED的实际工作时间,OLED的脉冲电流变大,使驱动MOS倒比管的尺寸减小;由于PWM信号占空比小,同时实现了OLED微小的平均像素驱动电流和亮度。结果表明PWM信号占空比为3%时,实现的OLED驱动电流和像素亮度范围分别为27pA~2.635nA、2.19~225.1cd/m~2,同时采用双像素版图共用技术,在15μm×15μm的像素面积内实现了像素驱动电路的版图设计。     

硅基液晶像素电路的研究

分析研究了微显示器件的场缓存技术与现有硅基液晶场缓存像素电路的结构特点,提出了一种新型的像素电路结构,此电路改变了以往电路结构中专门采用一个晶体管对像素电容进行放电的做法,通过同一个晶体管对像素电容进行充放电。电路经过Hspice仿真,对结果进行分析表明,其功能及特性符合设计要求,像素电容电荷保持率达到99%。电路具有结构简单,占用芯片面积小,像素电容电荷保持率高等优点,适合高亮度、高分辨率微显示器件的设计与制造。     

Functional Pixel Circuits for Elastic AMOLED Displays

While fabrication of active matrix organic LED (AMOLED) displays on plastic substrates continues to face technological challenges, stable electrical operation of thin-film transistor (TFT) pixel circuits under mechanical stress induced by substrate bending remains a critical issue. This paper investigates strain-induced shifts in hydrogenated amorphous silicon TFT characteristics and the compound impact on TFT circuit behavior. Measurements show that the magnitude of the shifts is determined by the direction of current flow in the TFT with respect to the bending stress orientation as well as bias conditions. Physically based compact models are developed that relate device characteristics to material behavior for design and optimization of AMOLED pixel circuits that can maintain immunity to bending stress. In particular, current mirror-based pixel circuits are presented that compensate for the long term threshold voltage shift and instantaneous strain-induced shifts in device characteristics.     

Stability analysis of current programmed a-Si:H AMOLED pixel circuits

In this paper, we present self-compensating current mirror-based pixel circuits, and analyze basic stability issues to provide a deeper understanding of circuit operation, and the impact of thin film transistor bias nonidealities, which can lead to the long-term (and gradual) instabilities in pixel drive current. The analysis also provides the circuit designer a means to tailor the pixel drive current stability to the long-term brightness degradation characteristics of the organic light-emitting diode.     

A numerical analysis of a CMOS image sensor with a simplefixed-pattern-noise-reduction technology

A 1/3-in 640×480-pixel CMOS image sensor with a simple fixed-pattern noise-reduction technology with a five-transistor pixel circuit and a low input-voltage current-voltage (I-V) converter was previously developed. In this report, we show that the low-input-voltage I-V converter with a current-mirror circuit improves the amplification factor and linearity of the pixel circuit. In a five-transistor pixel circuit, the threshold voltage of the X-Y addressing transistor affects the amplitude and the level of the readout pulse. An analysis of the mechanism of the X-Y addressing transistor shows the basic concept behind the selection of the threshold voltage. An L-shaped readout gate for a pinned photodiode is compared with a straight readout gate, and is proved to be adequate for rapid charge transfer     

Thin-film transistor fabrication for high brightness reconfigurablevacuum fluorescent displays

The design and fabrication of a thin-film transistor array for use in a reconfigurable, active matrix vacuum fluorescent display suitable for high ambient light operating conditions such as automotive instrument clusters is described. Thin-film transistor (TFT) arrays were fabricated in a novel 4-transistor per pixel configuration using a p-channel polycrystalline silicon transistor fabrication process. Display assembly was then completed by the Futaba Corporation. The robust transistor structure is capable of enduring the 550°C post-processing anneal temperature associated with phosphor deposition and packaging, Initial displays yielded luminances of 2500 ftL when operated at 40 V, and suggest an ultimate brightness of 5000 ftL for 55 V operation     

BCMD-An improved photosite structure for high-density image sensors

The author describes a new improved photosite structure and its use in a new image sensor that has been developed for applications requiring high-density pixel integration. The new photosite employs a buried-channel MOS transistor with a specially designed storage well located under the transistor channel in the silicon bulk. The photogenerated carriers accumulate in this well and modulate the transistor threshold. The resulting bulk charge modulated device (BCMD) has a high-sensitivity low-noise high-blooming overload capability, no detectable smear, and no image lag. The BMCD photocell has been integrated into an image-sensing array that has an 8-mm diagonal, 499 lines, and 687 pixels in each line. The individual cells are shaped into closely packed hexagons and are offset by a half pixel width between the neighbouring lines. The half pixel offset together with the dual-time readout capability gives the new sensor its superior resolution in color-sensing applications. The high light sensitivity throughout the entire visible spectrum is achieved by using a very thin polysilicon gate. The peripheral circuits needed for the array addressing and sensing functions are integrated on-chip using CMOS technology and require only the TTL driving pulses. The author further describes the basic steps of the sensor fabrication process and the results of testing and evaluation of completed units     

A New Pixel Circuit Compensating for Brightness Variation in Large Size and High Resolution AMOLED Displays

A new pixel design and driving method for active-matrix organic light-emitting diode (AMOLED) display using low-temperature polycrystalline silicon thin-film transistor (LTPS-TFT) is proposed. The new 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. The proposed pixel circuit has been verified to realize uniform output current by the simulation work using HSPICE software. The simulated error rate of the output current is also discussed in this paper. The novel pixel design has great potential for use in large size and high resolution AMOLED displays.     

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.     

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.