The content of the invention
In view of this, the embodiment of the present invention provides a kind of threshold voltage shift and electricity that can compensate for driving thin film transistor (TFT)The pixel-driving circuit of source voltage drop, to solve in the prior art in caused by manufacturing process, modular member aging and voltage drop etc.The problem of display inequality of organic light emitting diode display device.
To reach above-mentioned purpose, the invention provides a kind of organic light-emitting diode pixel drive circuit, has for drivingMachine light emitting diode is lighted, wherein the organic light-emitting diode pixel drive circuit includes：The first transistor, the second crystalline substanceBody pipe, third transistor, the 4th transistor, the 5th transistor, the first electric capacity, the second electric capacity and driving transistor；
Wherein, the first transistor, under the control of the second scanning signal, data-signal to be sent into describedFirst pole of one electric capacity；
The second transistor, under the control of the 3rd scanning signal, it is brilliant that reference signal to be sent into the drivingThe grid of body pipe；
The third transistor, under the control of the first scanning signal, reference signal to be sent into second electricityThe second pole held；
4th transistor, under the control of the 4th scanning signal, it is brilliant that data-signal to be sent into the drivingThe grid of body pipe；
5th transistor, under the control of the 3rd scanning signal, reference signal to be sent into first electricityThe second pole held and the first pole of the second electric capacity；
First electric capacity and second electric capacity, for compensating the threshold voltage of the driving transistor；
The driving transistor, for generating driving current according to the supply voltage；
Wherein, the Organic Light Emitting Diode, lighted corresponding to the driving current of driving transistor generation.
Further, the present invention also provides a kind of image element driving method for above-mentioned pixel-driving circuit, including：First scanning signal of scan line input, the second scanning signal of the second scan line input, the 3rd of three scan line input theUnder the control for the 4th scanning signal that scanning signal, the 4th scan line input, data-signal and reference using data wire inputThe reference signal of signal transmssion line input is driven transistor threshold voltage compensation deals so that drives the organic light emission twoThe driving current of pole tube light-emitting is unrelated with the drive transistor threshold voltage.
Further, the present invention also provides a kind of array base palte, includes above-mentioned organic light-emitting diode pixel drive circuit.
Further, the present invention also provides a kind of display device, includes above-mentioned array base palte.
Compared with prior art, organic light-emitting diode pixel drive circuit, array base palte and display provided by the inventionDevice, it can compensate for the influence that the threshold voltage shift of driving transistor is brought with supply voltage drop to image displaying quality, solutionDetermine in the prior art in the aobvious of organic light emitting diode display device caused by manufacturing process, modular member aging and voltage drop etc.The problem of showing inequality.
Embodiment
Hereinafter, embodiments of the present invention are explained with reference to the accompanying drawings.In addition, the present invention be not limited to it is following eachEmbodiment.
As shown in figure 1, according to the organic LED display device of embodiment of the present invention include array base palte 10, whenSequence control module, scan driver module and data drive module.
Array base palte 10 includes multiple pixel cells 11 arranged in arrays, and pixel cell 11 is according to from scan driver modulePass through a plurality of first scan line S1 (1) to S1 (n), a plurality of second scan line S2 (1) to S2 (n), a plurality of three scan line S3 (1)Pass through to S3 (n) and a plurality of 4th scan line S4 (1) to S4 (n) the respective scanned signals provided and from data-driven module moreCorresponding data signal that data line DL1 to DLm is provided lights.Therefore, the organic light-emitting diodes in a pixel cell 11Pipe pixel-driving circuit is multiple including Organic Light Emitting Diode OL ED and for driving Organic Light Emitting Diode OLED to lightTransistor and capacitance module.The detailed configuration of each pixel cell 11 will describe below in reference to Fig. 2.
Timing control module enables letter from external reception vertical synchronizing signal Vsync, horizontal-drive signal Hsync, dataNumber DE, clock signal clk and vision signal (not shown).In addition, timing control module in units of frame by outside inputVision signal is arranged as digital image data.For example, timing control module is same using vertical synchronizing signal Vsync, level is includedThe timing signal of step signal Hsync, data enable signal DE and clock signal clk controls scan driver module and data-drivenEach operation timing in module.Therefore, timing control module produces the choosing of the operation timing for controlling scan driver moduleLogical control signal GCS, and the data controlling signal DCS of the operation timing for control data drive module.
Scan driver module produces the first scanning signal Scan1, the second scanning signal Scan2, the 3rd scanning signal Scan3With the 4th scanning signal Scan4, enable the transistor that each pixel cell 11 included by array base palte 10 includes according toOperated from the gate control signal GCS of timing control module offer, and pass through the first scan line S1, the second scan line respectivelyS2, three scan line S3, the 4th scan line S4 believe the first scanning signal Scan1, the second scanning signal Scan2, the 3rd scanningNumber Scan3, the 4th scanning signal Scan4 are supplied to array base palte 10.
Data-driven module is produced using digital image data and the data controlling signal DCS provided from timing control moduleRaw data-signal, and caused data-signal Vdata is supplied to by array base palte 10 by corresponding data wire DL.
In this embodiment, data-driven module also includes being used to produce high level supply voltage Vdd, low level power electricityVee and reference signal Vref power module is pressed, by high level supply voltage transmission line PL (m) by high level supply voltageVdd is supplied to array base palte 10, and low level power voltage Vee is supplied into array base by low level power voltage transmission line ELOrganic Light Emitting Diode OLED negative electrode on plate 10, reference signal Vref is supplied to by reference to signal transmssion line CPL (ref)Array base palte 10.
Hereinafter, by referring to Figures 1 and 2 to the detailed of the organic light-emitting diode pixel drive circuit in each pixelConstruction illustrates.
Fig. 2 is the equivalent circuit diagram of organic light-emitting diode pixel drive circuit in the pixel for schematically show Fig. 1.Such as figureShown in 2, the organic light-emitting diode pixel drive circuit in each pixel cell 11 can include the first transistor T1, secondTransistor T2, third transistor T3, the 4th transistor T4, the 5th transistor T5, the 6th transistor T6, driving transistor Td,One electric capacity C1, the second electric capacity C2 and Organic Light Emitting Diode OLED.
The first transistor T1, second transistor T2, third transistor T3, the 4th transistor T4 and driving shown in Fig. 2 is brilliantBody pipe Td is N-type transistor, and the 5th transistor T5 and the 6th transistor T6 are P-type transistors, but not limited to this.It is used as anotherEmbodiment, such as it can also be provided that, the first transistor T1, second transistor T2, third transistor T3, the 4th transistor T4 andDriving transistor Td is P-type transistor, and the 5th transistor T5 and the 6th transistor T6 are N-type transistors, in this case, is usedThere is the polarity opposite with the voltage for N-type transistor to be turned in the voltage for turning on P-type transistor.
Specifically, in the present embodiment, the first transistor T1 the first pole receives data-signal Vdata, the first transistorT1 the second pole is connected to the first electric capacity C1 the first pole i.e. first node A, and the first transistor T1 grid receives the first scanningSignal Scan1, for the first electric capacity C1 the first electrode potential to be charged into data letter under the first scanning signal Scan1 controlNumber Vdata current potential, i.e. current potential at first node A are equal to data-signal Vdata current potential.
Second transistor T2 the first pole is connected to driving transistor Td grid i.e. at section point B, second transistorT2 the second pole is connected to the second electric capacity C2 the first pole i.e. at the 3rd node C, and second transistor T2 grid receives the 3rd and sweptSignal Scan3 is retouched, for reference signal Vref to be sent into driving transistor Td's under the 3rd scanning signal Scan3 controlGrid is at section point B.
Third transistor T3 the first pole is connected to the 5th transistor T5 the second pole i.e. at the 3rd node C, the 3rd crystalPipe T3 the second pole is connected to the second electric capacity C2 the second pole, and third transistor T3 grid receives the first scanning signal Scan1,For the second electric capacity C2 the second electrode potential to be charged to reference signal Vref electricity under the first scanning signal Scan1 controlPosition.
4th transistor T4 the second pole is connected to driving transistor Td grid i.e. at section point B, the 4th transistorT4 the first pole is connected to the first transistor T1 the second pole, and the 4th transistor T4 grid receives the 4th scanning signal Scan4,For data-signal Vdata to be sent to driving transistor Td grid i.e. second under the 4th scanning signal Scan4 controlAt node B.
5th transistor T5 the first pole receives reference signal Vref, and the 5th transistor T5 the second pole is connected to the first electricityIt is at the 3rd node C to hold C1 the second pole with the second electric capacity C2 the first pole, and the 5th transistor T5 grid receives the 3rd scanningSignal Scan3, under the 3rd scanning signal Scan3 control by the second electric capacity C2 the second electrode potential and the second electric capacity C2The first electrode potential charge to reference signal Vref current potential, i.e. current potential at the 3rd node C is equal to reference signal Vref electricityPosition.
6th transistor T6 the first pole is connected to driving transistor Td the second pole, and the 6th transistor T6 the second pole connectsIt is connected to Organic Light Emitting Diode OLED anode, the 6th transistor T6 grid receives the 4th scanning signal Scan4, for theDriving current I caused by driving transistor Td is sent to Organic Light Emitting Diode OLED under four scanning signal Scan4 controlAnode.
Organic Light Emitting Diode OLED anode is received caused by driving transistor Td under the 6th transistor T6 controlDriving current I, Organic Light Emitting Diode OLED negative electrode receive low level power voltage Vee, are sent out in the presence of driving current ILight.
In the present embodiment, the first transistor T1, second transistor T2, third transistor T3, the 4th transistor T4, the 5thTransistor T5, the 6th transistor T6 and driving transistor Td are respectively selected from metal-oxide-semiconductor field effect transistor, polycrystalline SiTFT, metalAny one in oxide thin film transistor, OTFT.And the first transistor T1, second transistor T2, the 3rdTransistor T3, the 4th transistor T4, the 5th transistor T5, the 6th transistor T6 and driving transistor Td first extremely source electrode,The first transistor extremely drains to the second of the 6th transistor.
In the present embodiment, second transistor T2 is different from the 5th transistor T5 channel type, for example, second transistorT2 is N-type transistor, and the 5th transistor T5 is P-type transistor；Can also be that second transistor T2 is P-type transistor, the 5th is brilliantBody pipe T5 is N-type transistor.
In the present embodiment, the first transistor T1, second transistor T2, third transistor T3, the 4th transistor T4 and driveDynamic transistor Td is N-type transistor, and the 5th transistor T5 and the 6th transistor T6 are P-type transistors.
Concrete operating principle is referred to shown in Fig. 3, Fig. 4 a-4b, and it is the drive in each pixel cell of first embodimentThe time diagram of dynamic circuit, the course of work of the drive circuit in each pixel cell are divided into charging stage, driving transistorTd threshold voltage compensation stage, Organic Light Emitting Diode OLED glow phases：
First stage is charging stage：Now, the first scanning signal Scan1, the second scanning signal Scan2 and the 4th scanningSignal Scan4 is high level signal, and the 3rd scanning signal Scan3 is low level signal, the first transistor T1, third transistorT3, the 4th transistor T4 and the 5th transistor T5 conductings, second transistor T2 and the 6th transistor T6 end.
The first transistor T1 is turned on, and the first electric capacity C1 the first electrode potential is charged to the electricity equal to data-signal VdataPosition, i.e. current potential at first node A are equal to data-signal Vdata current potential, meanwhile, the 4th transistor T4 conductings, by the second sectionPoint B is connected to the first electric capacity C1 the first pole i.e. at first node A, and now, the current potential at section point B is equal to first node AThe current potential at place is data-signal Vdata current potential；Third transistor T3 turns on the 5th transistor T5 so that the first electric capacity C1'sSecond pole is the current potential that current potential at the 3rd node C is equal to reference signal Vref, the second electric capacity C2 the first electrode potential and secondElectric capacity C2 the second electrode potential charges to reference signal Vref current potential simultaneously.
Second stage is the driving transistor Td threshold voltage compensation stage：First, the first scanning signal Scan1 is changed into lowLevel signal, the second scanning signal Scan2 and the 4th scanning signal Scan4 keep high level signal, the 3rd scanning signal Scan3Keep low level signal.Now, the first transistor T1, the 4th transistor T4 and the 5th transistor T5 are still tended to remain on,Third transistor T3 is changed into ending from turning on, and second transistor T2 and the 6th transistor T6 keep cut-off state.
When third transistor T3 is changed into cut-off state from turning on, the second electric capacity C2 discharges via driving transistor Td, makes driveDynamic transistor Td conductings, until the voltage difference between driving transistor Td grid and drain electrode is equal to driving transistor Td threshold valuesDuring voltage Vth, electric discharge terminates, now, because driving transistor Td grid is that current potential at section point B always remains as numberIt is believed that number Vdata current potential, then driving transistor Td drain electrode is that the voltage that fourth node D goes out is (Vdata-Vth).Cross hereinCheng Zhong, because the 5th transistor T5 is held on, although the current potential of the second electric capacity C2 the second pole is changed into (Vdata-Vth),It is that the current potential of the second electric capacity C2 the first pole can remain reference signal Vref current potential.
Then, the second scanning signal Scan2 sports low voltage signal, the 3rd scanning signal Scan3 by high voltage signalHigh voltage signal is sported, now, the first transistor T1, the 4th transistor T4 and the 5th transistor T5 end, while second is brilliantBody pipe T2 is turned on, and third transistor T3 and the 6th transistor T6 remain in that cut-off state.Due to second transistor T2 conductings4th transistor T4 ends, and driving transistor Td grid is changed to be connected to by original the first pole for being connected to the first electric capacity C1Second electric capacity C2 the first pole, because the current potential of the second electric capacity C2 the first pole is the current potential of driving transistor Td grid,Namely the current potential that the current potential of driving transistor Td grid is reference signal Vref by data-signal Vdata potential jump, it is existingThe current potential of driving transistor Td grid is taken as Vg, then now driving transistor Td grid potential Vg=Vref, and nowBecause third transistor T3 is in cut-off state, therefore driving transistor Td drain potential is remained in that as Vs=Vdata-Vth。
Phase III t3 is Organic Light Emitting Diode OLED glow phase：Now, the first scanning signal Scan1, secondScanning signal Scan2 and the 4th scanning signal Scan4 is low level signal, and the 3rd scanning signal Scan3 is high level signal,The first transistor T1, third transistor T3, the 4th transistor T4 and the 5th transistor T5 end, second transistor T2, the 6th crystalline substanceBody pipe T6 turns on driving transistor Td.
Now, driving transistor Td grid potential Vg and driving transistor Td drain potential Vs voltage difference Vgs are：
Vgs=Vg-Vs=Vref- (Vdata-Vth)=Vref-Vdata+Vth
Therefore, it can be seen from transistor is operated in the formula of the current characteristics of saturation region, the drive of driving transistor Td outputsStreaming current is：
I=K (Vgs-Vth) ^2=K (Vref-Vdata+Vth-Vth) ^2=K (Vref-Vdata) ^2
Because the 4th scanning signal Scan4 is low level, the 6th transistor T6 is turned on, the driving of driving transistor Td outputsElectric current I can drive Organic Light Emitting Diode OLED to light.Wherein, Vg is driving transistor Td grid potential, and Vs is drivingTransistor Td drain potential.
From above-mentioned driving current I formula it is recognised that the driving current I and driving transistor of driving transistor Td outputsThe high level supply voltage Vdd that Td threshold voltage vt h and driving Organic Light Emitting Diode OLED are luminous is unrelated, so as to overcomeDriving transistor Td threshold voltage vt h drift and due to caused by the resistance on high level power transmission line PL (m) notWith the difference for the high level supply voltage Vdd being an actually-received between the drive circuit of pixel cell, and caused by different OLEDWhen receiving identical viewdata signal, drive what whole image of its luminous driving current also caused by difference was shownThe problem of uneven.
Can be to due to driving transistor Td according to the organic light-emitting diode pixel drive circuit of embodiment of the present inventionThreshold voltage vt h deviation and high level supply voltage Vdd voltage drop caused by Organic Light Emitting Diode OLEDThe change of the electric current of flowing compensates, and is based on the reference signal Vref and data-signal Vdata, and being used in driving hasDriving transistor Td driving current luminous machine light emitting diode OLED and threshold voltage vt h deviation and high level power supply electricityPress Vdd voltage drop unrelated, be a constant current so as to keep it well, the threshold value electricity for solving driving transistor TdPress Vth drift and due between the drive circuit of different pixels unit caused by the resistance on high level power transmission line PL (m)The difference for the high level supply voltage Vdd being an actually-received, and caused by different OLED receiving identical view dataDuring signal, drive its luminous driving current also difference caused by whole image show it is uneven the problem of.
The of the transistor (the first transistor to the 6th transistor and driving transistor) being previously mentioned in the embodiment of the present inventionOne extremely can be the source electrode (or drain electrode) of transistor, and the second of transistor extremely can be that (or source electrode, this regards crystalline substance for the drain electrode of transistorDepending on the type of body pipe).If the source electrode of transistor is the first pole, then the drain electrode of the transistor is the second pole；If crystalThe drain electrode of pipe is the first pole, then the source electrode of the transistor is the second pole.Specific mode of operation may be referred to foregoing teachings,This is repeated no more.
The present invention also provides a kind of array base palte, including organic light-emitting diode pixel provided in an embodiment of the present invention drivingCircuit.Because the organic light-emitting diode pixel drive circuit on the array base palte can be to the threshold value electricity due to driving transistorThe deviation of pressure and the change of the electric current flowed in Organic Light Emitting Diode caused by the voltage drop of high level supply voltage are enteredRow compensation, and the reference voltage and data voltage are based on, it is used in the driving crystal of driving organic light-emitting diodeThe voltage drop of the driving current of pipe and the deviation of threshold voltage and high level supply voltage is unrelated, so as to keep it wellFor a constant current, solves the drift of the threshold voltage of driving transistor and because the resistance on high level power transmission line is ledThe difference for the high level supply voltage being an actually-received between the drive circuit of the different pixels unit of cause, and caused by it is differentOLED drives whole image of its luminous driving current also caused by difference to show when receiving identical viewdata signalShow it is uneven the problem of.
The embodiment of the present invention additionally provides a kind of display device, including the array base palte that the above embodiment of the present invention provides.Because the organic light-emitting diode pixel drive circuit in the display device can be to the threshold voltage due to driving transistorDeviation and the change of the electric current flowed in Organic Light Emitting Diode caused by the voltage drop of high level supply voltage are mendedRepay, and be based on the reference voltage and data voltage, be used in the driving transistor of driving organic light-emitting diodeThe voltage drop of the deviation and high level supply voltage of driving current and threshold voltage is unrelated, is one so as to keep it wellConstant current, solves the drift of the threshold voltage of driving transistor and due to caused by the resistance on high level power transmission lineThe difference for the high level supply voltage being an actually-received between the drive circuit of different pixels unit, and caused by different OLED existWhen receiving identical viewdata signal, whole image of its luminous driving current also caused by difference is driven to show notThe problem of uniform.
It should be noted that it will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of an alternative embodiment, it is attachedModule or flow in figure are not necessarily implemented necessary to the present invention.
It will be appreciated by those skilled in the art that the module in device in embodiment can describe be divided according to embodimentIt is distributed in the device of embodiment, respective change can also be carried out and be disposed other than in one or more devices of the present embodiment.OnThe module for stating embodiment can be merged into a module, can also be further split into multiple submodule.