CN102867479A - 维持二极管发光亮度的补偿电路 - Google Patents
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Abstract
本发明公开一种维持二极管发光亮度的补偿电路,所述维持二极管发光亮度的补偿电路包含稳定单元、第一晶体管、第二晶体管、第三晶体管、第四晶体管以及有机发光二极管。稳定单元包含光电二极管及补偿电容。第二晶体管用于控制数据输入的时间。当该有机发光二极管于发光的阶段,第三晶体管持续放电或充电稳定单元中的节点,使该节点的电位与VSS或VDD的电位相同。如此,能维持有机发光二极管组件亮度的稳定性。
Description
技术领域
本发明涉及一种补偿电路,特别是涉及一种可维持有机发光二极管发光组件亮度稳定性的补偿电路。
背景技术
有源矩阵有机发光二极管(Active-Matrix Organic Light-Emitting Diode,AMOLED)显示器拥有厚度薄、重量轻、自发光、低驱动电压、高效率、高对比、高色彩饱和度、反应速度快、可饶曲等特色,被视为继薄膜晶体管液晶显示器(Thin Film Transistor Liquid Crystal Display,TFT-LCD)之后,最被看好的新兴显示技术。
但由于有机发光二极管(Organic Light Emitting Diode,OLED)组件所表现出的亮度是由流过的电流大小所决定的,因此如果要精确控制像素亮度就必须要做到精确控制电流,相对于TFT-LCD只要控制写入像素的电压电平就能控制像素亮度,难度可以说是相当高。
实际上AMOLED也遇到了许多问题。请同时参照图1和图2,图1为无补偿的P型晶体管AMOLED像素电路架构的电路示意图;图2为无补偿的N型晶体管AMOLED像素电路架构的电路示意图。如图所示,因为OLED电流IOLED是由数据电压VDATA利用操作在饱和区的薄膜晶体管(Thin-FilmTransistor,TFT)T2来转换成的电流,以N型T2来说,其公式为IOLED=1/2×W/L×μN×COX(VGS-VTH)2,当AMOLED经过长时间的使用之后,T2的VTH会变大,以及载子移动率(Mobility)μN也会变小,如此一来便会使IOLED下降,造成OLED的亮度衰减。
此外,由于OLED材料老化的现象,在长时间操作下,会发生跨压逐渐上升以及发光效率下降的问题。OLED跨压的上升可能会影响到薄膜晶体管的操作,以N型薄膜晶体管为例,若OLED接在薄膜晶体管的源极端,当OLED跨压上升时会直接影响到薄膜晶体管的栅极-源极之间的端电压源极,也就是直接影响流过的电流。而在发光效率方面,若因长时间操作造成材料老化发光效率下降,那么即使是流过相同的电流也无法产生预期的亮度。若红(R)、绿(G)、蓝(B)三色的发光效率下降程度不同,更会发生色偏的问题。但材料改善不易,因此这并不是一个能轻易解决的问题。
又,随着面板尺寸的加大,信号线逐渐变长,其内阻效应会日益明显,最后会影响面板亮度的均匀性,此现象称之为I-R Drop。请参照图3,图3为I-R Drop的示意图。如图所示,VDD与VSS信号线会随着内阻效应产生压差,进而导致AMOLED面板不同位置像素会有不同大小的电流,影响面板亮度的均匀性。
发明内容
鉴于上述现有技术中的问题,本发明的目的就是提供一种维持二极管发光亮度的补偿电路,以解决现有技术中存在的如发光效率下降,以及因OLED电流IOLED下降使得有机发光二极管(Organic Light Emitting Diode,OLED)组件发光亮度降低的问题。
根据本发明的目的,提出一种维持二极管发光亮度的补偿电路,包含稳定单元、第一晶体管、第二晶体管、第三晶体管、第四晶体管以及发光二极管。稳定单元包含光电二极管及电容,该稳定单元的一端为第一节点,该稳定单元的另一端为第二节点,且光电二极管及电容之间具有第三节点。第一晶体管连接第一电源、第一控制信号及第一节点。第二晶体管连接第二电源、第一控制信号及第二节点。第三晶体管连接第三电源、第二控制信号及第三节点。发光二极管连接第三电源及第四晶体管。第四晶体管连接第一晶体管、发光二极管,藉由开启第四晶体管以导通发光二极管。
其中,第一晶体管及第二晶体管分别为第一P型薄膜晶体管及第二P型薄膜晶体管,第三晶体管及第四晶体管分别为第一N型薄膜晶体管及第二N型薄膜晶体管。
其中,第二P型薄膜晶体管控制第二电源输入的时间。
其中,当发光二极管于发光的阶段,第一N型薄膜晶体管持续放电第三节点使第三节点的电位与第三电源的电位相同。
其中,电容储存电位差,该电位差由光电二极管的电阻值上升而产生。
其中,第一晶体管及第二晶体管分别为第一N型薄膜晶体管及第二N型薄膜晶体管,第三晶体管及第四晶体管系分别为第一P型薄膜晶体管及第二P型薄膜晶体管。
其中,第二N型薄膜晶体管控制第二电源输入的时间。
其中,当发光二极管于发光的阶段,第一P型薄膜晶体管持续充电第三节点,使第三节点的电位与第三电源的电位相同。
其中,电容储存电位差,该电位差由光电二极管的电阻值上升而产生。
承上所述,根据本发明的维持二极管发光亮度的补偿电路,可具有下述优点:
所述维持二极管发光亮度的补偿电路可解决现有技术中的如发光效率下降,以及因IOLED下降使得OLED组件发光亮度降低的问题,进而可维持OLED组件发光亮度的稳定性。
附图说明
图1为无补偿的P型晶体管AMOLED像素电路架构的电路示意图。
图2为无补偿的N型晶体管AMOLED像素电路架构的电路示意图。
图3为I-R Drop的示意图。
图4为根据本发明的维持二极管发光亮度的补偿电路的第一实施例的电路示意图。
图5为根据本发明的维持二极管发光亮度的补偿电路的第一实施例的信号波形示意图。
图6为根据本发明补偿电路的第一实施例的二极管顺偏特性的示意图。
图7为根据本发明的维持二极管发光亮度的补偿电路的第二实施例的电路示意图。
图8为根据本发明的维持二极管发光亮度的补偿电路的第二实施例的信号波形示意图。
图9为根据本发明补偿电路的第二实施例的二极管顺偏特性的示意图。
主要的附图标号说明:1、2为补偿电路,T1、T2、T3、T4为薄膜晶体管,D为光电二极管,C、Cst为电容,Emit[n]、Scan[n]为控制信号,VDD、VSS、VData为电源信号,IDD、ID、IOLED为电流,ΔR为内阻抗,OLED为有机发光二极管,A、B、E为节点。
具体实施方式
以下将参照相关附图,说明根据本发明的维持二极管发光亮度的补偿电路的实施例,为便于理解,下述实施例中的相同组件以相同的标号表示来说明。
请参照图4,图4为根据本发明的维持二极管发光亮度的补偿电路的第一实施例的电路示意图。如图所示,本发明的补偿电路包含了两个P型薄膜晶体管(Thin-Film Transistor,TFT)T1及T2、两个N型薄膜晶体管T3及T4、一个光电二极管(Photodiode)D以及一个电容C。在本实施例中,还包含了两个控制信号Emit[n]、Scan[n]以及三个电源信号VDD、VSS和VData。其中T4可用于驱动有机发光二极管(Organic Light Emitting Diode,OLED);其余T1至T3可作为开关使用,电容C用于补偿。
在所有作为开关的TFT中,在数据写入阶段,T1使T4能够形成二极管式连接(Diode-Connection)并导通,当前面所述的那些会造成OLED组件发光亮度衰减的因素产生的时候,会让OLED组件的发光亮度衰减,使得像素中的光电二极管D(在本实施例中,光电二极管D可等效成光感电阻器)的电阻值上升进而影响到实际写入到像素的电压值,并将其储存在补偿电容C内。T2可为一般像素电路都具备的开关,用于控制数据输入的时间。T3则在有源矩阵有机发光二极管(Active-Matrix Organic Light-Emitting Diode,AMOLED)像素进入发光阶段时将节点A持续放电至VSS,正因为A点维持在VSS,不是浮接(Floating)的状态,所以不会因为VData改变受到T2的漏电流(Leakage Current)影响而改变,因此像素内不须如先前技术中所描述的Cst来维持A点的电位。
请参照图5,图5为本发明的维持二极管发光亮度的补偿电路的第一实施例的信号波形示意图。如图所示,在本实施例中,补偿电路操作步骤可分为两个阶段。
首先为检测OLED发光亮度调整像素数据电位写入的阶段:
Scan[n]与Emit[n]信号将T1、T2、T4导通,T3截止,此时节点B的电位VB=VDD,在OLED发光亮度最亮的原始状态下,且可将像素中的光电二极管D(在本实施例中,光电二极管D可等效成光感电阻器)的电阻值近似等效成RD,A点电位VA会由VSS变成VSS+ΔVA(在本实施例中,ΔVA为正值),假设写入的数据电压VData=VLevel+VD0+VSS(在本实施例中,VD0为光电二极管D无电流时候的跨压),数据扫描时间(Data Scan Time)(也就是Scan[n]将T1、T2、T4导通的时间)为T=2RDC,则
其中,所有灰阶电压(VLevel大于0,最小为σ,σ为一常数)的写入,均需要2RDC时间。
请同时参照图6,图6为本发明的补偿电路的第一实施例的二极管顺偏特性的示意图。如图所示,当前述会造成IOLED下降的因素产生的时候,会让OLED组件的发光亮度衰减,使得光感电阻器的电阻值上升由RD变成RD’,则A点电位VA’会由VSS变成VSS+ΔVA’。其中,斜线61的斜率为1/RD;斜线62的斜率为1/RD’。
接着为OLED组件发光显示阶段:
Scan[n]与Emit[n]信号将T1、T2截止,T3导通,B点此时为浮接的状态,A点电位VA会由VSS+ΔVA变成VSS,其变化量为-ΔVA,B点电位VB受到A点电容耦合效应会变成VDD-ΔVA=VDD-VLevel。其中,VL0=VDD、VL255=σ。
当前述会造成IOLED下降的因素产生的时候,A点电位VA’会由VSS+ΔVA’变成VSS,其变化量为-ΔVA’。B点电位VB’受到A点电容耦合效应会变成VDD-ΔVA’=VDD-RD/RD’×VLevel。如此,VB’大于VB。不管所写入的灰阶电压(VLevel)为何,N型薄膜晶体管T4的栅极电压均会变大以达到补偿效果。
针对I-R Drop,远离VDD、VSS信号输入端的AMOLED像素,其看到的VDD及VSS分别会变成VDD-I×R以及VSS+I×R,B点电位VB受到A点电容耦合效应会变成(VDD-I×R)-ΔVA=(VDD-I×R)-(VLevel-I×R)=VDD-VLevel,相同于靠近VDD、VSS信号输入端的AMOLED像素,所以并不会受到I-R Drop效应影响。
请参照图7,图7为根据本发明的维持二极管发光亮度的补偿电路的第二实施例的电路示意图。如图所示,本发明的补偿电路2包含了两个P型薄膜晶体管T3及T4、两个N型薄膜晶体管T1及T2、一个光电二极管D以及一个电容C。在本实施例中,还包含了两个控制信号Emit[n]、Scan[n]以及三个电源信号VDD、VSS和VData。其中T4可用于驱动OLED;其余T1至T3可作为开关使用,电容C用作补偿。
在所有作为开关的TFT中,在数据写入阶段,T1使得T4能够形成二极管连接(Diode-Connection)并导通,当前面所述的那些会造成OLED组件发光亮度衰减的因素产生的时候,会让OLED组件的发光亮度衰减,使得像素中的光电二极管D(在本实施例中,光电二极管D可等效成光感电阻器)的电阻值上升进而影响到实际所写入到像素的电压值,并将其储存在补偿电容C内。T2可以为一般像素电路都具备的开关,用于控制数据输入的时间。T3则是在AMOLED像素进入发光阶段时将节点A持续充电至VDD,正因为A点维持在VDD,不是浮接的状态,所以不会因为VData改变受到T2的漏电流影响而改变,因此像素内不须如先前技术中所描述的Cst来维持A点的电位。
请参照图8,图8为根据本发明的维持二极管发光亮度的补偿电路的第二实施例的信号波形示意图。如图所示,在本实施例中,补偿电路操作步骤可分为两个阶段。
首先为检测OLED发光亮度调整像素数据电位写入的阶段:
Scan[n]和Emit[n]信号将T1、T2、T4导通,T3截止,此时节点B的电位VB=VSS,在OLED发光亮度最亮的原始状态下,且可将像素中的光电二极管D(在本实施例中,光电二极管D可等效成光感电阻器)的电阻值近似等效成RD,A点电位VA会由VDD变成VDD+ΔVA(在本实施例中,ΔVA为负值),假设写入的数据电压VData=VDD-VLevel-VD0(在本实施例中,VD0为光电二极管D无电流时候的跨压),数据扫描时间(Data Scan Time)(也就是Scan[n]将T1、T2、T4导通的时间)为T=2RDC,则
其中,所有灰阶电压(VLevel大于0,最小为σ,σ为常数)的写入,均需2RDC时间。
请同时参照图9,图9为根据本发明的补偿电路的第二实施例的二极管顺偏特性的示意图。如图所示,当前述会造成IOLED下降的因素产生的时候,会让OLED组件的发光亮度衰减,使得光感电阻器的电阻值上升由RD变成RD’,则A点电位VA’会由VDD变成VDD+ΔVA’。其中,斜线91的斜率为1/RD;斜线92的斜率为1/RD’。
接着为OLED组件发光显示阶段:
Scan[n]和Emit[n]信号变为VSS,T1、T2截止,T3导通,B点此时为浮接的状态,A点电位VA会由VDD+ΔVA变成VDD,其变化量为-ΔVA,B点电位VB受到A点电容耦合效应会变成VSS-ΔVA=VSS+VLevel。其中,VL0=VDD、VL255=σ。
当前述会造成IOLED下降的因素产生的时候,A点电位VA’会由VDD+ΔVA’变成VDD,其变化量为-ΔVA’。B点电位VB’受到A点电容耦合效应会变成VSS-ΔVA’=VSS+RD/RD’×VLevel。如此,VB’小于VB。不管所写入的灰阶电压(VLevel)为何,P型薄膜晶体管T4的栅极电压均会变小以达到补偿效果。
针对I-R Drop,远离VDD、VSS信号输入端的AMOLED像素,其看到的VDD及VSS分别会变成VDD-I×R以及VSS+I×R,B点电位VB受到A点电容耦合效应会变成(VSS+I×R)-ΔVA=(VSS+I×R)-(-VLevel+I×R)=VSS+VLevel,相同于靠近VDD、VSS信号输入端的AMOLED像素,所以并不会受到I-R Drop效应影响。
综上所述,本发明所提出的维持二极管发光亮度的补偿电路可解决现有技术中的如发光效率下降,以及因IOLED下降使得OLED组件发光亮度降低的问题,进而可维持OLED组件发光亮度的稳定性。
以上所述仅为示例性的,而非限制性的。任何未脱离本发明的精神与范围,而对其进行的等效修改或变更,均应包含于权利要求的范围内。
尽管参照其典型实施例表示和描述了本发明的实施例,以举例说明本发明的原理,但本发明并不限于表示和描述的实施例。应该理解,在不脱离由权利要求限定的本发明的精神和范围的情况下,本领域的技术人员可进行各种变动和修改。因此,应该理解,这样的变动、修改及其等同物全部包括在本发明的范围内。
Claims (18)
1.一种维持二极管发光亮度的补偿电路,其特征在于,包含:
稳定单元,包含光电二极管及电容,该稳定单元的一端为第一节点,所述稳定单元的另一端为第二节点,且所述光电二极管及所述电容之间具有第三节点;
第一晶体管,连接第一电源、第一控制信号及所述第一节点;
第二晶体管,连接第二电源、所述第一控制信号及所述第二节点;
第三晶体管,连接第三电源、第二控制信号及所述第三节点;
发光二极管,连接所述第三电源及第四晶体管;以及
所述第四晶体管,连接所述第一晶体管、所述发光二极管,藉由开启所述第四晶体管以导通所述发光二极管。
2.根据权利要求1所述的维持二极管发光亮度的补偿电路,其特征在于,所述第一晶体管及所述第二晶体管分别为第一P型薄膜晶体管及第二P型薄膜晶体管,所述第三晶体管及所述第四晶体管分别为第一N型薄膜晶体管及第二N型薄膜晶体管。
3.根据权利要求2所述的维持二极管发光亮度的补偿电路,其特征在于,所述电容的一端连接所述光电二极管的电流输出端以形成所述第三节点,而所述电容未连接所述光电二极管的另一端为所述第一节点,所述光电二极管的未连接所述电容的另一端为所述第二节点。
4.根据权利要求2所述的维持二极管发光亮度的补偿电路,其特征在于,所述第一P型薄膜晶体管的源极连接所述第一电源,所述第一P型薄膜晶体管的栅极系连接所述第一控制信号,及所述第一P型薄膜晶体管的漏极连接所述第二N型薄膜晶体管的栅极。
5.根据权利要求2所述的维持二极管发光亮度的补偿电路,其特征在于,所述第二P型薄膜晶体管的源极连接所述第二电源,所述第二P型薄膜晶体管的栅极连接所述第一控制信号,及所述第二P型薄膜晶体管的漏极连接所述光电二极管的电流输入端,即所述第二节点。
6.根据权利要求2所述的维持二极管发光亮度的补偿电路,其特征在于,所述第一N型薄膜晶体管的漏极连接所述第三节点,所述第一N型薄膜晶体管的栅极连接所述第二控制信号,及所述第一N型薄膜晶体管的源极连接所述第三电源。
7.根据权利要求2所述的维持二极管发光亮度的补偿电路,其特征在于,所述第二N型薄膜晶体管的漏极连接所述第一电源,所述第二N型薄膜晶体管的栅极连接所述第一节点,及所述第二N型薄膜晶体管的源极连接所述发光二极管的电流输入端。
8.根据权利要求2所述的维持二极管发光亮度的补偿电路,其特征在于,所述第二P型薄膜晶体管控制所述第二电源输入的时间。
9.根据权利要求2所述的维持二极管发光亮度的补偿电路,其特征在于,当所述发光二极管于发光的阶段,所述第一N型薄膜晶体管持续放电所述第三节点,使所述第三节点的电位与所述第三电源的电位相同。
10.根据权利要求1所述的维持二极管发光亮度的补偿电路,其特征在于,所述第一晶体管及所述第二晶体管分别为第一N型薄膜晶体管及第二N型薄膜晶体管,所述第三晶体管及所述第四晶体管分别为第一P型薄膜晶体管及第二P型薄膜晶体管。
11.根据权利要求10所述的维持二极管发光亮度的补偿电路,其特征在于,所述电容的一端连接所述光电二极管的电流输入端以形成所述第三节点,而所述电容未连接所述光电二极管的另一端为所述第一节点,所述光电二极管未连接所述电容的另一端为所述第二节点。
12.根据权利要求10所述的维持二极管发光亮度之补偿电路,其特征在于,所述第一N型薄膜晶体管的漏极连接所述第一节点,所述第一N型薄膜晶体管的栅极连接所述第一控制信号,及所述第一N型薄膜晶体管的源极连接所述第一电源。
13.根据权利要求10所述的维持二极管发光亮度的补偿电路,其特征在于,所述第二N型薄膜晶体管的漏极连接所述第二电源,所述第二N型薄膜晶体管的栅极连接所述第一控制信号,及所述第二N型薄膜晶体管的源极连接所述光电二极管的电流输出端,即所述第二节点。
14.根据权利要求10所述的维持二极管发光亮度的补偿电路,其特征在于,所述第一P型薄膜晶体管的源极连接所述第三电源,所述第一P型薄膜晶体管的栅极连接所述第二控制信号,及所述第一P型薄膜晶体管的漏极连接所述第三节点。
15.根据权利要求10所述的维持二极管发光亮度的补偿电路,其特征在于,所述第二P型薄膜晶体管的源极连接所述发光二极管的电流输出端,所述第二P型薄膜晶体管的栅极连接所述第一节点,及所述第二P型薄膜晶体管的漏极连接所述第一电源。
16.根据权利要求10所述的维持二极管发光亮度的补偿电路,其特征在于,所述第二N型薄膜晶体管控制所述第二电源输入的时间。
17.根据权利要求10所述的维持二极管发光亮度的补偿电路,其特征在于,当所述发光二极管于发光的阶段,所述第一P型薄膜晶体管持续充电所述第三节点,使所述第三节点的电位与所述第三电源的电位相同。
18.根据权利要求1所述的维持二极管发光亮度的补偿电路,其特征在于,所述电容储存电位差,所述电位差由所述光电二极管的电阻值上升而产生。
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111292676A (zh) * | 2018-11-20 | 2020-06-16 | 群创光电股份有限公司 | 电子装置 |
CN111883063A (zh) * | 2020-07-17 | 2020-11-03 | 合肥维信诺科技有限公司 | 像素电路、显示面板及显示装置 |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103325342B (zh) * | 2013-06-26 | 2015-12-09 | 京东方科技集团股份有限公司 | 一种amoled像素电路及其驱动方法、显示装置 |
US9320090B2 (en) | 2014-06-19 | 2016-04-19 | Phoseon Technology, Inc. | LED output response dampening for irradiance step response output |
KR102662881B1 (ko) * | 2018-12-31 | 2024-05-03 | 엘지디스플레이 주식회사 | 광학 지문 센싱 회로를 포함한 화소 회로, 화소 회로의 구동 방법, 및 유기 발광 표시 장치 |
CN113674692B (zh) * | 2021-09-03 | 2023-04-07 | 深圳市华星光电半导体显示技术有限公司 | 电压降补偿方法、装置及电子设备 |
WO2023079674A1 (ja) * | 2021-11-05 | 2023-05-11 | シャープディスプレイテクノロジー株式会社 | 表示装置およびその駆動方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1573872A (zh) * | 2003-05-26 | 2005-02-02 | 精工爱普生株式会社 | 显示装置、显示方法以及显示装置的制造方法 |
CN101297343A (zh) * | 2005-10-26 | 2008-10-29 | 皇家飞利浦电子股份有限公司 | 有源矩阵显示设备 |
US7944415B2 (en) * | 2005-07-27 | 2011-05-17 | Silicon Display Technology Co., Ltd. | Organic light emitting diode display device and a driving method thereof |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4484451B2 (ja) | 2003-05-16 | 2010-06-16 | 奇美電子股▲ふん▼有限公司 | 画像表示装置 |
CA2443206A1 (en) * | 2003-09-23 | 2005-03-23 | Ignis Innovation Inc. | Amoled display backplanes - pixel driver circuits, array architecture, and external compensation |
US7612818B2 (en) * | 2004-03-29 | 2009-11-03 | Toshiba Matsushita Display Technology Co., Ltd. | Input sensor containing display device and method for driving the same |
KR100646935B1 (ko) * | 2004-06-24 | 2006-11-23 | 삼성에스디아이 주식회사 | 발광 표시장치 |
KR101157979B1 (ko) | 2005-06-20 | 2012-06-25 | 엘지디스플레이 주식회사 | 유기발광다이오드 구동회로와 이를 이용한유기발광다이오드 표시장치 |
JP5259132B2 (ja) * | 2006-12-27 | 2013-08-07 | 三星ディスプレイ株式會社 | 周辺光感知回路及びこれを有する平板表示装置 |
KR100957948B1 (ko) * | 2008-02-19 | 2010-05-13 | 삼성모바일디스플레이주식회사 | 광센서 및 그를 이용한 평판표시장치 |
TW201239849A (en) * | 2011-03-24 | 2012-10-01 | Hannstar Display Corp | Pixel circuit of light emitting diode display and driving method thereof |
TWI442374B (zh) * | 2011-08-16 | 2014-06-21 | Hannstar Display Corp | 有機發光二極體補償電路 |
-
2011
- 2011-07-08 TW TW100124392A patent/TWI441137B/zh active
- 2011-08-04 CN CN201110226777.6A patent/CN102867479B/zh active Active
-
2012
- 2012-01-19 US US13/354,058 patent/US8779666B2/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1573872A (zh) * | 2003-05-26 | 2005-02-02 | 精工爱普生株式会社 | 显示装置、显示方法以及显示装置的制造方法 |
US7944415B2 (en) * | 2005-07-27 | 2011-05-17 | Silicon Display Technology Co., Ltd. | Organic light emitting diode display device and a driving method thereof |
CN101297343A (zh) * | 2005-10-26 | 2008-10-29 | 皇家飞利浦电子股份有限公司 | 有源矩阵显示设备 |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111292676A (zh) * | 2018-11-20 | 2020-06-16 | 群创光电股份有限公司 | 电子装置 |
CN111292676B (zh) * | 2018-11-20 | 2021-09-07 | 群创光电股份有限公司 | 电子装置 |
CN111883063A (zh) * | 2020-07-17 | 2020-11-03 | 合肥维信诺科技有限公司 | 像素电路、显示面板及显示装置 |
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US8779666B2 (en) | 2014-07-15 |
CN102867479B (zh) | 2015-06-03 |
US20130009550A1 (en) | 2013-01-10 |
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TW201303829A (zh) | 2013-01-16 |
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