基于IGZO薄膜晶体管的高可靠性时分驱动GOA电路  

Highly Reliable Gate Driver on Array Circuit Using Time-Division Driving Method Base on IGZO Thin Film Transistor

作　　者：周刘飞 邵贤杰 王海宏 王保平[1] ZHOU Liu-fei;SHAO Xian-jie;WANG Hai-hong;WANG Bao-ping(School of Electronic Science and Engineering,Southeast University,Nanjing,Jiangsu 210096,China;Research and Development Department,Nanjing BOE Display Technology Co.,Ltd.,Nanjing,Jiangsu 210033,China)

机构地区：[1]东南大学电子科学与工程学院,江苏南京210096 [2]南京京东方显示技术有限公司研发部,江苏南京210033

出　　处：《电子学报》2023年第12期3463-3472,共10页Acta Electronica Sinica

摘　　要：本文提出一种新颖的基于IGZO(Indium Gallium Zinc Oxide)薄膜晶体管的双向扫描集成栅极驱动(Gate Driver on Array,GOA)电路,特别适用于in-cell触控显示.本文提出的GOA电路采用时分驱动方式(Time-Division Driving Method,TDDM)实现高报点率的in-cell触控,并防止触控信号失真.该GOA电路支持扫描-暂停-重启模式,即输出几十个连续的显示寻址扫描脉冲后,栅极驱动输出暂停以执行触控侦测.在触控侦测期间,GOA电路中的Touch控制单元开始工作,使所有栅极输出低电位以消除显示驱动信号对触控的干扰.此外,本文提出的GOA电路采用双低电平维持(Low Level Maintaining,LLM)模块,能有效抑制LLM晶体管的阈值电压漂移.电学模拟结果表明,本文提出的GOA电路无论工作于正向还是反向扫描,均能产生均匀的输出波形,并且停坑级的输出波形与正常级波形一致.采用IGZO晶体管制作了10.4英寸in-cell触控显示面板以验证本文提出的GOA电路,支持90 Hz显示刷新率与180 Hz触控报点率.此外,借助工艺与设计优化,进一步提高GOA电路在恶劣环境下的使用寿命,成功通过高温高湿(85℃/85%)操作500 h的可靠性测试.This paper presents a novel bidirectional gate driver on array(GOA)circuit based on IGZO(Indium Gallium Zinc Oxide)thin film transistor(TFT),especially for use in in-cell touch displays.The proposed GOA circuit exploits the time-division driving method(TDDM)to implement the in-cell touch panels with a high report rate and prevent the distortion of touch signals.This GOA circuit can operate in a scanning-pausing-restarting mode,i.e.,after outputting dozens of continuous scanning pulses of display addressing,the gate driver outputs pause for touch sensing periods.During the time interval for touch operation,touch control unit of proposed GOA is started to work,so that all gate lines will output low potential in order to eliminate interferences from display driving signals.Moreover,the proposed GOA utilizes dual low-level maintaining(LLM)units to suppress threshold voltage shift of LLM TFTs.The operation principle of the GOA is described in detail.The simulated results illustrate that the proposed GOA circuit generates uniform output waveforms regardless of whether the circuit operates in forward or backward scanning,and output waveform in touch holding stage is almost identical to that in normal stage.We fabricated 10.4 inches in-cell touch display panel using IGZO TFT to assess the proposed GOA,and 90 Hz display with 180 Hz touch reporting rate can be perfectly supported.Moreover,the lifetime of GOA circuit under harsh environment is further improved with process and design optimization,the reliability test such as operation at high temperature and humidity(85℃/85%)500 hours has been successfully passed.

关 键 词：IGZO薄膜晶体管 集成栅极驱动 时分驱动法 可靠性 阈值电压漂移 内置触控 

分 类 号：TN321.5[电子电信—物理电子学]