含非晶硅薄膜晶体管和液晶象素单元的电路模拟程序

本文主要介绍了一个适用于计算机模拟的非晶硅薄膜晶体管(TFT)和液晶象素单元的电路模拟程序。     

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.     

A new pixel circuit for active matrix organic light emitting diodes

We propose a new thin-film-transistor (TFT) pixel circuit for active-matrix organic light-emitting diode (AMOLED) composed of four TFTs and two capacitors. The simulation results, based on the device performances measured for an OLED and a poly-Si TFT, indicate that the proposed circuit has high immunity to the variation of poly-Si TFT characteristics     

基于低温多晶硅薄膜晶体管的AMOLED交流像素电路

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.     

VT Compensation Circuit for AM OLED Displays Composed of Two TFTs and One Capacitor

In this paper, we propose the threshold-voltage compensation pixel circuit that is composed of two thin-film transistors (TFTs) and one capacitor (2T1C). It not only compensates the deviation of the threshold voltage of the driver TFT but also actualizes the large aperture ratio for organic light-emitting diode (OLED) devices as well as the traditional 2T1C circuit. We show the result of SPICE simulation for the pixel circuit; it indicates that the circuit can allocate the relatively large aperture ratio for OLED devices     

Mirrored OLED pixel circuit for threshold voltage and mobility compensation with IGZO TFTs

In this paper, pixel circuit using mirroring structure with Indium–Gallium–Zinc oxide (IGZO) thin film transistors (TFTs) for active matrix organic light emitting diode (AMOLED) display is proposed. This pixel circuit consists of only four TFTs, and one capacitor. Due to the mirroring structure, characteristic of the driving TFT can be precisely sensed by the sensing TFT, which is deployed in a discharging path for gate electrode of the driving TFT. This discharging process is strongly dependent on threshold voltage (V_T) and effective mobility of the sensing TFT. Circuit operating details are discussed, and compensation effects for threshold voltage shift and mobility variations are verified through numerical derivation and SPICE simulations. Furthermore, compared with conventional schematics, the proposed pixel circuit might have much simplified external driving circuits, and it is a promising alternative solution of high performance AMOLED display.     

A novel current-scaling a-Si:H TFTs pixel electrode circuit for AM-OLEDs

Hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) pixel electrode circuit with a function of current scaling is proposed for active-matrix organic light-emitting displays (AM-OLEDs). In contrast to the conventional current mirror pixel electrode circuit, in this circuit a high data-to-organic light-emitting device (OLED) current ratio can be achieved, without increasing the a-Si:H TFT size, by using a cascade structure of storage capacitors. Moreover, the proposed circuit can compensate for the variations of TFT threshold voltage. Simulation results, based on a-Si:H TFT and OLED experimental data, showed that a data-to-OLED current ratio larger than 10 and a fast pixel programming time can be accomplished with the proposed circuit.     

A new a-Si:H thin-film transistor pixel circuit for active-matrix organic light-emitting diodes

We propose a new pixel circuit using hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs), composed of three switching and one driving TFT, for active-matrix organic light-emitting diodes (AMOLEDs) with a voltage source method. The circuit simulation results based on the measured threshold voltage shift of a-Si:H TFTs by gate-bias stress indicate that this circuit compensates for the threshold voltage shifts over 10000 h of operation.     

A novel a-Si:H AMOLED pixel circuit based on short-term stress stability of a-Si:H TFTs

This letter presents a novel pixel circuit for hydrogenated amorphous silicon (a-Si:H) active matrix organic light-emitting diode displays employing the short-term stress stability characteristics of a-Si:H thin film transistors (TFTs). The pixel circuit uses a programming TFT that is under stress during the programming cycle and unstressed during the drive cycle. The threshold voltage shift (V/sub T/-shift) of the TFT under these conditions is negligible. The programming TFT in turn regulates the current of the drive TFT, and the pixel current therefore becomes independent of the threshold voltage of the drive TFT.     

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。     

A New Poly-Si TFT Current-Mirror Pixel for Active Matrix Organic Light Emitting Diode

A new poly-Si thin-film-transistor (TFT) current-mirror-active-matrix-organic-light-emitting-diode (AMOLED) pixel, which successfully compensates for the variation of the threshold voltage as well as mobility in the excimer laser annealed poly-Si TFT pixel, is designed and fabricated. The OLED current$(I_ OLED)$of the proposed pixel does not depend on the operating temperature. When the temperature of pixel is increased from 27$^circhboxC$to 60$^circhboxC$, the$I_ OLED$of the new pixel circuit composed of four TFTs and one capacitor increases only about 1.5%, while that of a conventional pixel composed of two TFTs and one capacitor increases about 37%. At room temperature, nonuniformity of the$I_ OLED$in the proposed circuit was also considerably suppressed at around 9%. We have successfully fabricated a 1.2-in AMOLED panel$(hbox96 times hbox96 times hboxred green blue)$to evaluate the performance of the proposed pixel. A troublesome residual image caused by the hysteresis phenomenon of the poly-Si TFT was almost eliminated in the proposed AMOLED panel as a result of current programming.     

Dynamic Pixel Models for a‐Si TFT‐LCD and Their Implementation in SPICE

A dynamic analysis of an amorphous silicon (a‐Si) thin film transistor liquid crystal display (TFT‐LCD) pixel is presented using new a‐Si TFT and liquid crystal (LC) capacitance models for a Simulation Program with Integrated Circuit Emphasis (SPICE) simulator. This dynamic analysis will be useful when predicting the performance of LCDs. The a‐Si TFT model is developed to accurately estimate a‐Si TFT characteristics of a bias‐dependent gate to source and gate to drain capacitance. Moreover, the LC capacitance model is developed using a simplified diode circuit model. It is possible to accurately predict TFT‐LCD characteristics such as flicker phenomena when implementing the proposed simulation model.     

有机薄膜晶体管阵列面向电子纸像素设计

讨论了有机薄膜晶体管(Organic Thin Film Transistor,OTFT)作为开关器件来驱动电子纸的像素设计,特别是像素电路结构、HSPICE模拟用模型参数和像素平面结构。讨论了有机薄膜晶体管制造过程,并用HSPIC模拟分析了有机薄膜晶体管结构和存贮电容大小对像素波形的影响,结果表明TFT结构的选择依赖于存贮电容的大小。     

Three-TFT image sensor for real-time digital X-ray imaging

A new current-programmed, current-output active TFT image sensor suitable for real-time X-ray imaging (e.g. fluoroscopy) using hydrogenated amorphous silicon (a-Si:H) thin-film-transistor (TFT) technology is introduced. The proposed pixel circuit can successfully compensate for characteristic variations such as mobility and threshold voltage shift in a-Si:H TFTs. Simulation and measurement results show that high on-pixel amplification can be accomplished with this pixel circuit.     

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.     

In-process functional testing of pixel circuit in AM-OLEDs

This paper presents a functional testing scheme using a two-thin-film-transistor (TFT) pixel circuit of an active-matrix organic light-emitting display (AM-OLED). This pixel circuit and the co-operative electrical testing scheme can not only evaluate the characteristics of each TFT, but also determine the location of line and point defects in the TFT array. Information on defects can be used in a unique repair system that cutting and repairing these defects. Furthermore, the functional testing scheme can be applied as a part of yield management of the AM-OLED array process.     

AMOLED电流镜像像素电路的稳定性分析

a—Si：HTFT在长时间施加直流栅偏压下将导致晶体管闽值电压漂移,造成OLED的发光亮度下降,影响其使用寿命。而多管的像素电路设计可以补偿或消除阂值电压的漂移。本文分析了电流控制电流镜像像素电路的工作原理。结合a—Si：HTFT阈值漂移模型仿真了电路在长时间工作下阈值漂移对驱动电流稳定性的影响,并提出了相应的解决办法。研究结果表明合理的像素电路设计可以有效改善驱动电流的稳定性。     

有源矩阵有机电致发光像素电路的研究进展

有源驱动方式的有机发光二极管（AMOLED）较之无源驱动方式易于实现高亮度和高分辨率、功耗更小,更适合大屏幕显示。但传统的两管驱动电路会出现驱动管阈值电压在整个屏幕上分布不均匀,或长时间加偏压后驱动管的阂值电压发生漂移。本文在两管驱动电路的基础上介绍了几种最近提出的补偿电路并描述了它们的改善效果及各自存在的问题。     

TFT AMLCD像素矩阵电路中栅延迟的模拟研究

建立了ａ－ＳｉＴＦＴＡＭＬＣＤ的等效电路模型,综合考虑栅信号线电阻、栅与源信号线的交叠电容以及ＴＦＴ导电沟道电容构成的ＲＣ（ＲｅｓｉｓｔｉｖｉｔｙＣａｐａｃｉｔａｎｃｅ）常数,模拟计算了栅信号延迟对液晶显示屏尺寸、显示分辨率及栅信号电极材料的依赖关系,为实现器件优化设计提供参考。     

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