CN104183211A - Pixel circuit, driving method thereof, and light-emitting display - Google Patents
Pixel circuit, driving method thereof, and light-emitting display Download PDFInfo
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Abstract
The invention provides a pixel circuit which comprises the components of: a scanning line; a data line; a first power line; a second power line; a light emitting element which is connected between the first power line and the second power line; a driving transistor which comprises a gate electrode and is connected between the light emitting element and the second power line; a first switch which comprises a second electrode and a first control electrode that is connected with the scanning line, wherein the second electrode is connected with the data line; a second switch which comprises a second control electrode that is connected with the scanning line, and the second switch is connected between the first switch and the gate electrode; a third switch which is connected between the driving transistor and the light emitting element; a first capacitor which comprises a first end and a second end, wherein the first end is connected with the gate electrode, and the second end is connected with the second power line; and a second capacitor which comprises a first end and a second end, wherein the first end is connected with the scanning line, and the second end is connected with the gate electrode. The pixel circuit can compensate a threshold voltage and eliminates effects caused by problems of uneven electron mobility of the driving transistor and power supply voltage IR drop, etc. to light-emitting current of the light emitting element, thereby improving display brightness uniformity of a light-emitting display.
Description
Technical field
The present invention relates to data drive circuit field, especially one can surge valve threshold voltage, reduce IR pressure drop affects, thereby the active display that reduces the image element circuit of luminance difference between pixel and driving method thereof and comprise this image element circuit.
Background technology
Organic light emitting display technology has self luminous characteristic, very thin coating of organic material and the glass substrate of general employing made, in the time having electric current to pass through, these organic materials will be luminous, and OLED display screen visible angle is large, and can significantly save electric energy, the simultaneously advantage of the high and high reaction velocity of luminescence efficiency, so be widely applied at MP3 player since this display device in 2003, therefore, Organic Electricity laser display technology is always by insider is had an optimistic view of.
Please refer to Fig. 1, is the Organization Chart of image element circuit in traditional organic light-emitting display device.This image element circuit comprises organic luminescent device OLED, driving transistors M2, capacitor Cst and switching transistor M1, simultaneously, image element circuit is connected with sweep signal Scan (N), data voltage Vdata, pixel power vd D and external power source VSS, wherein, VSS is the voltage (can be for example ground voltage) lower than pixel supply voltage; Switching transistor M1 have be connected to data voltage Vdata source electrode, be connected to the drain electrode of capacitor C 1 first end and be connected to the grid of sweep signal Scan (N); Driving transistors M2 have be connected to pixel power vd D source electrode, be connected to the drain electrode of organic luminescent device OLED and be connected to the grid of capacitor C 1 first end; The second end of capacitor C 1 connects the source electrode of driving transistors M2.
In the time that image element circuit is worked, driving transistors M2 response signal provides electric current to organic luminescent device OLED, thereby it is luminous that organic luminescent device OLED is carried out.Wherein, just can be controlled at the strength of current in driving transistors M2 by the data-signal of data voltage Vdata and switching transistor M1 input.In addition, capacitor C 1 is within the predetermined cycle, and it can maintain the voltage between driving transistors M2 source electrode and grid by response data voltage.
So, in the time that the grid of switching transistor M1 responds sweep signal Scan (N) opening switch transistor M1, data voltage Vdata just starts capacitor C 1 to charge, and subsequently the voltage in capacitor C 1 is applied to the grid of driving transistors M2, thereby open driving transistors M2, make electric current flow through organic luminescent device OLED and carry out luminous.
Following formula provides to the electric current of organic luminescent device OELD from driving transistors M2 in order to calculate.
Wherein, I
oLEDit is the electric current that flows through organic luminescent device OELD; Vgs is the voltage applying between driving transistors M2 source electrode and grid; Vth is the threshold voltage of driving transistors M2, and Vdata is data voltage; β is the gain factor of driving transistors M2.
So, from above-mentioned formula A, can find out, the electric current that flows through organic luminescent device OLED can be activated the threshold voltage of transistor M2 and the impact of pixel voltage VDD and change.But due to the impact of procedure for producing, each transistorized threshold voltage and electron mobility in organic light-emitting display device are all not identical, even if so just directly caused giving identical data voltage, the electric current I that it produces in circuit
oLEDalso still can be variant, thereby cause brightness disproportionation, can be with further reference to Fig. 2, for the organic light-emitting device electric current of flowing through in conventional pixel circuit in Fig. 1 is with the simulated data broken line graph that changes of input data voltage, respectively at the corresponding broken line of benchmark Vth(Vth shift0), the corresponding broken line of Vth(Vth shift0.3 of forward migration) and the Vth(Vth shift-0.3 correspondence broken line of negative offset) in situation, the organic light-emitting device electric current I of flowing through
oLEDchange and carried out digital simulation, therefrom can find out, along with the increase of data voltage Vdata, the I that different Vth are corresponding
oLEDalso occurred larger difference, naturally, also there is the phenomenon of brightness disproportionation in the brightness between each pixel; And pixel voltage VDD also can be owing to occurring in circuit that IR-falls and the problem that causes equally brightness disproportionation.
In addition,, in general current compensation method, also usually can run into and make because input data current is too little showing the not good problem of appearance compensation under low gray scale states.
Summary of the invention
For surge valve threshold voltage and get rid of the impact of problem on light-emitting component glow current such as electron mobility inequality, the IR pressure drop of supply voltage of driving transistors in prior art, the active display that the invention provides a kind of-image element circuit and driving method thereof and comprise this image element circuit.
The invention provides a kind of image element circuit, this image element circuit comprises: sweep trace; Data line; The first power lead; Second source line; Light-emitting component, is connected between the first power lead and second source line; Driving transistors, comprises a grid, and this driving transistors is connected between this light-emitting component and this second source line; The first switch, comprise the second electrode and the first control electrode that is connected to this sweep trace, and this second electrode connects this data line; Second switch, comprises the second control electrode that is connected to this sweep trace, and this second switch is connected between this first switch and this grid; The 3rd switch, is connected between this driving transistors and this light-emitting component; The first electric capacity, comprises the first end that is connected to this grid and the second end that is connected to this second source line; And second electric capacity, comprise the first end that is connected to this sweep trace and the second end that is connected to this grid.
As optional scheme, in described image element circuit, this light-emitting component comprises the anode that is connected to this first power lead and the negative electrode that is connected to the 3rd switch the first electrode.
As optional scheme, in described image element circuit, this driving transistors also comprises the drain electrode that is connected to the 3rd switch the second electrode and the source electrode that is connected to this second source line.
As optional scheme, in described image element circuit, the second end of the first end of an electrode of this second switch, this first electric capacity, this second electric capacity and the grid of this driving transistors are connected in first node.
As optional scheme, in described image element circuit, this image element circuit also comprises emission control drive wire, and wherein, the 3rd switch comprises the 3rd control electrode that is connected to this emission control drive wire.
As optional scheme, in described image element circuit, this first switch, second switch and the 3rd switch are Thin Film Transistor (TFT).
The present invention also provides a kind of active display, and this active display comprises: display panel, and this display panel comprises: a plurality of pixel cells, each this pixel cell comprises image element circuit as claimed in claim 1; Scan drive cell, in order to provide sweep signal to this image element circuit; Data-driven unit, in order to provide data-signal to this image element circuit; Emission control driver element, in order to provide emissioning controling signal to these a plurality of control lines; The first power supply, in order to apply the first voltage to this first power lead; And second source, in order to apply second voltage to this second source line; Wherein, the magnitude of voltage of second voltage is lower than the magnitude of voltage of this first voltage.
As optional scheme, in described active display, this display device also comprises emission control driver element, and wherein, this emission control driver element provides emissioning controling signal to this image element circuit, to control the break-make of the 3rd switch.
In addition, the present invention also further provides a kind of image element driving method, is applied in described image element circuit, and this driving transistors has a threshold voltage, and this driving method comprises:
A. this first switch of conducting, this second switch and this driving transistors, turn-off the 3rd switch, and the data voltage of the corresponding output of this data line is applied to this first electric capacity, makes this this data voltage of the first capacitance stores;
B. conducting the 3rd switch and this driving transistors, turn-off this first switch, this second switch, and the voltage between this drive transistor gate and source electrode equals the voltage of this first capacitance stores, utilizes the voltage of this first capacitance stores to drive this light-emitting component luminous.
As optional scheme, corresponding output scanning signal of this sweep trace in described driving method, wherein, this sweep signal is cyclical signal, when this sweep signal is during in high level, this first switch and this second switch are in conducting state.
As optional scheme, in described driving method, this image element circuit also comprises emission control drive wire, the corresponding output of this emission control drive wire control signal, wherein, this control signal is cyclical signal, and when this control signal is during in high level, the 3rd switch is in conducting state.
As optional scheme, in described driving method, this data voltage is greater than this threshold voltage.
As optional scheme, the corresponding output of this sweep trace one periodically variable sweep signal in described driving method, wherein, in the time that this sweep signal is transformed into low level by high level, this first electric capacity responds a voltage change, and this step B further comprises: the voltage of this first capacitance stores equals the difference of this data voltage and this voltage change.
As optional scheme, in described driving method, before this steps A, also comprise steps A 1: turn-off this first switch, this second switch, the 3rd switch and this driving transistors, this first electric capacity and this second electric capacity all keep existing state.
As optional scheme, in described driving method, between this steps A and this step B, also comprise steps A 2: turn-off this first switch, this second switch, the 3rd switch and this driving transistors, this first electric capacity keeps being stored in this steps A this data voltage of this first electric capacity.
Compared with prior art, utilize image element circuit of the present invention and driving method thereof and active display, the effectively threshold voltage of compensation for drive transistor, get rid of again the impact of problem on light-emitting component glow current such as electron mobility inequality, the IR pressure drop of supply voltage of driving transistors, thereby well improved the uniformity coefficient of active display display brightness.In addition, utilize larger data voltage writing pixel circuit, can avoid low GTG especially time, data voltage is too small and in data write the period, cannot be full of the first capacitor C 1, and then causes the not good problem of subsequent compensation.
Brief description of the drawings
Fig. 1 is the Organization Chart of image element circuit in traditional organic light-emitting display device;
Fig. 2 flows through organic light-emitting device electric current with the simulated data broken line graph that changes of input data voltage in conventional pixel circuit in Fig. 1;
Fig. 3 is the basic structure block diagram of active display in the embodiment of the present invention;
Fig. 4 is the circuit structure diagram of image element circuit in one embodiment of the invention;
Fig. 5 is the waveform schematic diagram of sweep signal, emissioning controling signal and the data-signal in one embodiment of image element circuit of Fig. 4;
The intersegmental electric current schematic diagram of image element circuit in Fig. 4 of flowing through when Fig. 6 A, 6B are respectively T1, T2 in Fig. 5 waveform;
Fig. 7 is the simulated data broken line graph that organic light-emitting device electric current changes with input data current of flowing through in the image element circuit of Fig. 4;
Fig. 8 is the waveform schematic diagram of the image element circuit of Fig. 4 sweep signal, emissioning controling signal and the data-signal in another kind of embodiment;
Fig. 9 is the schematic diagram of image element circuit in the intersegmental Fig. 4 that flows through when T1, T3 in Fig. 8 waveform.
Embodiment
For making that object of the present invention, structure, feature and function thereof are had to further understanding, hereby coordinate embodiment to be described in detail as follows.
Please refer to Fig. 3 and Fig. 4, Fig. 3 is the basic structure block diagram of active display in the embodiment of the present invention, and Fig. 4 is the circuit structure diagram of image element circuit in one embodiment of the invention.In an embodiment of the present invention, active display 1 mainly comprises scan drive cell 10, data-driven unit 20, emission control driver element 30, display panel 60, wherein, this display panel 60 comprises a plurality of pixel cells 50, and each pixel cell 50 comprises image element circuit 100 as shown in Figure 4.Therefore in the time that active display 1 carries out work, scan drive cell 10, data-driven unit 20, emission control driver element 30 is respectively in order to provide sweep signal, data-signal and emissioning controling signal are to this pixel cell 50, further, scan drive cell 10 is by a plurality of sweep traces S[1], S[2] ... S[N] corresponding provide sweep signal to the pixel cell 50 of every a line, data-driven unit 20 is by a plurality of data lines D[1], D[2] ... D[M] corresponding provide data-signal to the pixel cell 50 of each row, emission control driver element 30 is by a plurality of launch-control lines EM[1], EM[2] ... EM[N] corresponding provide emissioning controling signal to the pixel cell 50 of every a line, wherein, M, N is greater than 0 natural number.In addition, this active display 1 also comprises the first power supply 41, in order to apply the first voltage VDD to the first power lead 410; Second source 42, in order to apply second voltage VSS to second source line 420, wherein, in the ordinary course of things, preferred, the magnitude of voltage of second voltage VSS will be lower than the magnitude of voltage of the first voltage VDD, and in the present embodiment, this second voltage VSS is ground voltage.
Carry out the image element circuit with further reference to as shown in Figure 4 below, in this embodiment, image element circuit 100 comprises: sweep trace again; Data line S[N], in order to sweep signal S1; The first power lead 410 and second source line 420, transmit respectively the first voltage VDD that the first power supply 41 and second source 42 export and second voltage VSS to image element circuit 100; And launch-control line EM[N], in order to provide control signal EM to image element circuit 100.Further, image element circuit 100 also comprises:
Light-emitting component OLED, is connected between the first power lead 410 and second source line 420;
Driving transistors M4, comprises grid G, source S and drain D, and driving transistors M4 is connected between light-emitting component OLED and second source line 420;
The first switch M1, comprises the second electrode and is connected to sweep trace S[N] the first control electrode, and the second electrode connection data line D[M], in order to optionally to receive data voltage Vdata;
Second switch M2, comprises and is connected to sweep trace S[N] the second control electrode, and second switch M2 is connected between the first switch M1 and grid G;
The 3rd switch M3, comprises and is connected to emission control drive wire EM[N] the 3rd control electrode, and it is connected between driving transistors M4 and light-emitting component OLED;
The first capacitor C 1, comprises the first end that is connected to grid G and the second end that is connected to second source line 420; And
The second capacitor C 2, comprises and is connected to sweep trace S[N] first end be connected to the second end of grid G.
Wherein, the light-emitting component in the present embodiment is taking Organic Light Emitting Diode (OLED) as example, but not as limit, this light-emitting component can be also inorganic light-emitting diode or other luminescent devices; And the first switch M1, the second switch M2 in the present embodiment and the 3rd switch M3 can be preferably Thin Film Transistor (TFT), but also not as limit, it can be also other electron devices that can realize switching function.
More specifically, in the present embodiment, light-emitting component has an anode and a negative electrode, its anode is connected with the first power lead 410, its negative electrode is connected with one end of the 3rd switch M3, it should be noted that, when in the situation of the 3rd switch M3 and the equal conducting of driving transistors M4, the 3rd switch M3, driving transistors M4 and light-emitting component OLED between the first power lead 410 and second source line 420 can form a series via, now, utilize following equation to calculate to flow through the electric current of light-emitting component OLED:
Wherein, in the present embodiment, I
oLEDit is the electric current that flows through light-emitting component OELD; Vgs is the voltage applying between driving transistors M4 grid G and source S; Vth is the threshold voltage of driving transistors M4; β is the gain factor of driving transistors M4.Therefore can find out from this equation 1, utilize voltage between driving transistors M4 grid G and source S can control the electric current of the light-emitting component OLED that flows through, thereby change its luminous intensity, utilize the break-make of the 5th switch M3 can realize the control to above-mentioned series via, whether drive this light-emitting component OLED luminous thereby control.
Please again with reference to image element circuit 100 as shown in Figure 3, in the present embodiment, an electrode of second switch M2, the first end of the first capacitor C 1, the second end of the second capacitor C 2 and the grid G of driving transistors M4 are connected in first node A, wherein, the first switch M1 is except the first control electrode, also comprise the first electrode and the second electrode, its second electrode is connected to data line D[M] in order to receive data voltage Vdata, the first electrode is connected to the drain D of driving transistors M4, same, second switch M2 and the each switch of the 3rd switch M3 are except control electrode, all also comprise other two electrodes, as shown in Figure 3, the first electrode of second switch M2 is also connected to the drain D of driving transistors M4, its second electrode is connected to above-mentioned first node A, the first electrode of the 3rd switch M3 is connected with the negative electrode of light-emitting component OLED, and its second electrode is connected to the drain D of driving transistors M4.
Please with further reference to Fig. 5, it is the waveform schematic diagram of the image element circuit of Fig. 4 sweep signal, emissioning controling signal and data-signal in one embodiment.In this embodiment, sweep trace S[N] the sweep signal S1 and launch-control line EM[N of corresponding output] the emissioning controling signal EM of corresponding output is cyclical signal, and as shown in Figure 5 be above-mentioned two signals and the waveform schematic diagram of data-signal in one-period.Wherein, incorporated by reference to Fig. 5, with reference to figure 4, when sweep signal S1 is during in high level, the first switch M1 and second switch M2 are in conducting state; And same, when emissioning controling signal EM is during in high level, the 3rd switch M3 is in conducting state.
Within a work period as shown in Figure 5, the course of work of image element circuit 100 is generally divided into two stages: write compensated stage and launching phase.It should be noted that, waveform schematic diagram shown in Fig. 5 is the drive waveforms figure that respectively drives signal under emission mode in image element circuit 100 connecting, so-called emission mode continuously refers in display panel 60 that each pixel 50 is by sweep signal S[N] corresponding scanning sequency drives line by line, its concrete driving process is common in prior art, therefore do not repeat at this.So, for the principle of work of image element circuit 100 in better key diagram 4 with and advantage place, specially coordinate following image element driving method to add a supplementary explanation.
For two working stages of image element circuit 100 as above, image element driving method of the present invention comprises following two steps:
A. conducting the first switch M1, second switch M2 and driving transistors M4, turn-offs the 3rd switch M3, data line D[M] the data voltage Vdata of corresponding output is applied to the first capacitor C 1, makes first capacitor C 1 this data voltage of storage Vdata;
B. conducting the 3rd switch M3 and driving transistors M4, turn-offs the first switch M1, second switch M2, and the voltage between driving transistors M4 grid G and source S equals the voltage that the first capacitor C 1 is stored, and utilizes the voltage that the first capacitor C 1 is stored to drive light-emitting component luminous.
Wherein, please specifically in conjunction with Fig. 5 with reference to Fig. 6 A to Fig. 6 B, the intersegmental electric current schematic diagram of image element circuit in Fig. 4 of flowing through when it is respectively T1, T2 in Fig. 5 waveform.Steps A is corresponding to the compensation write phase of image element circuit 100, intersegmental in the time of T1, as shown in Figure 6A, sweep signal S1 in high level and emissioning controling signal EM in low level, therefore, the first switch M1, second switch M2 and driving transistors M4 are all in conducting state, and the 3rd switch M3 is in turn-offing cut-off state, now, data line D[M] corresponding data voltage Vdata is applied to first node A by the first switch M1 of conducting, the simultaneously electric current driving transistors M4 that also can flow through, in fact, in this period, data voltage Vdata can charge to the first capacitor C 1, to make first capacitor C 1 this data voltage of storage Vdata.It should be noted that, in this embodiment, the magnitude of voltage of data voltage Vdata is greater than the absolute value of the threshold voltage Vth of driving transistors M4, therefore can obtain following equation:
Vdata=|Vth|+Vx [equation 2]
Wherein, Vdata is data line D[M] corresponding data voltage; Vth is the threshold voltage of driving transistors M4, and Vx is the difference voltage of Vdata and Vth.In addition, because intersegmental the 3rd switch M3 when the T1 is in turn-offing cut-off state, so light-emitting component OLED intersegmental in the time of T1 be non-luminous.
Below with further reference to Fig. 6 B, step B is corresponding to the launching phase of image element circuit 100, intersegmental in the time of T2, sweep signal S1 in low level and emissioning controling signal EM in high level, therefore, the first switch M1, second switch M2 and driving transistors M4 are all in conducting state, and the 3rd switch M3 is in turn-offing cut-off state, now, the 3rd switch M3, driving transistors M4 and light-emitting component OLED between the first power lead 410 and second source line 420 can form a series via, and light-emitting component OLED starts luminous.When enter into T2 period from the T1 period, sweep signal S1 has dropped to low level VGL from high level VGH, and now the first capacitor C 1 and the second capacitor C 2 are serially connected in sweep trace S[N] and second source line VSS between, so the change in voltage that the first capacitor C 1 can response the second capacitor C 2 first ends, and can obtain the first capacitor C 1 and respond the equation of the voltage change Vp that above-mentioned change in voltage obtains according to series capacitance voltage divider principle:
Wherein, the capacitance of C1, C2 corresponding the first capacitor C 1 of difference and the second capacitor C 2, VGH and VGL be the magnitude of voltage of corresponding sweep signal S1 low and high level respectively.
And within the T2 period, the first capacitor C 1 is connected between driving transistors M4 grid G and source S, so the voltage between driving transistors M4 grid G and source S equals the voltage that the first capacitor C 1 is stored, therefore can drive light-emitting component OLED luminous according to the known voltage that utilizes the first capacitor C 1 to store of equation 1 again, and the voltage Vc that now the first capacitor C 1 is stored equals the difference of data voltage Vdata and voltage change Vp, therefore, further, in conjunction with equation 1, equation 2 and equation 3, the calculation equation 4 of light-emitting component OLED electric current can obtain in the time of launching phase, flowing through in the present invention:
So, can find out from equation 4, in the flow through electric current I of light-emitting component OLED of launching phase
oLEDonly press the value of VGH, VGL relevant (in fact with the height ordinary telegram of difference voltage Vx, sweep signal S1, the size of difference voltage Vx directly depends on data voltage Vdata), in other words, it is intersegmental to driving transistors M4 threshold voltage in the time of T1 that utilization has compensated the data voltage Vdata of Vth | the compensation of Vth|, reduce threshold voltage to flowing through the current affects of light-emitting component OLED, and then well improved the homogeneity of active display 1 brightness.In addition, utilize the change of data voltage Vdata to change difference voltage Vx, and then realize light-emitting component OLED and send the light of brightness in various degree, thereby make active display 1 can cash out grey menu.It will be further appreciated that, because the final luminous time difference value voltage Vx of light-emitting component OLED will deduct a fixing voltage change Vp, so in the time that pixel cell 50 need to write low GTG signal, can write the first capacitor C 1 with higher data voltage, thereby while having avoided low GTG, data voltage is too small and cannot within the T1 period, be full of the first capacitor C 1, and then causes the not good problem of subsequent compensation.
Advantage of the present invention please refer to Fig. 7 in order better to illustrate, the simulated data broken line graph that the organic light-emitting device electric current of flowing through in the image element circuit for Fig. 4 changes with input data current.Respectively at the corresponding broken line of benchmark Vth(Vth shift0), the corresponding broken line of Vth(Vth shift0.3 of forward migration) and the Vth(Vth shift-0.3 correspondence broken line of negative offset) in situation, the organic light-emitting device electric current I of flowing through
oLEDchange and carried out digital simulation, therefrom can find out, along with the increase of data voltage Vdata, the I that different Vth are corresponding
oLEDthe difference occurring, obviously than (corresponding diagram 2) I in prior art
oLEDthe difference that corresponding different Vth present is much smaller.
In addition, please refer to Fig. 8, is the waveform schematic diagram of the image element circuit of Fig. 4 sweep signal, emissioning controling signal and the data-signal in another kind of embodiment.Same, in this embodiment, sweep trace S[N] the sweep signal S1 and launch-control line EM[N of corresponding output] the emissioning controling signal EM of corresponding output is cyclical signal, and as shown in Figure 8 be above-mentioned two signals and the waveform schematic diagram of data-signal in one-period.Wherein, incorporated by reference to Fig. 8, with reference to figure 4, when sweep signal S1 is during in high level, the first switch M1 and second switch M2 are in conducting state; When emissioning controling signal EM is during in high level, the 3rd switch M3 is in conducting state.
Within a work period as shown in Figure 8, the course of work of image element circuit 100 is generally divided into four-stage: data keep the stage, write compensated stage, data keeps stage and launching phase.It should be noted that, waveform schematic diagram shown in Fig. 8 is the drive waveforms figure that respectively drives signal under synchronized transmissions pattern in image element circuit 100, so-called synchronized transmissions pattern refer in display panel 60 each pixel 50 can wait until all pixels 50 all after data writing voltage the same time drive, its concrete driving process is common in prior art, therefore do not repeat at this.
For four working stages of image element circuit 100 as above, the image element driving method in this embodiment comprises following four steps:
A1. turn-off the first switch M1, second switch M2, the 3rd switch M3 and driving transistors M4, the first capacitor C 1 and the second capacitor C 2 all maintain the original state;
A. conducting the first switch M1, second switch M2 and driving transistors M4, turn-offs the 3rd switch M3, data line D[M] the data voltage Vdata of corresponding output is applied to the first capacitor C 1, makes first capacitor C 1 this data voltage of storage Vdata;
A2. turn-off the first switch M1, second switch M2, the 3rd switch M3 and driving transistors M4, the first capacitor C 1 keeps being stored in this steps A this data voltage Vdata of the first capacitor C 1;
B. conducting the 3rd switch M3 and driving transistors M4, turn-off the first switch M1, second switch M2, voltage between driving transistors M4 grid G and source S equals the voltage that the first capacitor C 1 is stored, and utilizes the voltage that the first capacitor C 1 is stored to drive light-emitting component OLED luminous.
Compared with image element driving method in a upper embodiment, image element driving method in this embodiment has increased steps A 1 and steps A 2, wherein, steps A and step B write compensated stage and launching phase corresponding to image element circuit 100, and the principle of work in these two stages is identical with the principle of the steps A of narrating in a upper embodiment and step B, intersegmental in the time of T2, T4, the principle of work of image element circuit 100 during with T1, T2 in a upper embodiment intersegmental principle of work identical, therefore do not repeat at this.And in this embodiment, it should be noted that steps A 1 and steps A 2, corresponding to the course of work of T1 and T3 interval pixel circuit, please further combined with Fig. 8 with reference to Fig. 9, be the schematic diagram of image element circuit in the intersegmental Fig. 4 that flows through when T1, T3 in Fig. 8 waveform.Intersegmental in the time of T1 and T3, sweep signal S2 and emissioning controling signal EM are all in low level, now, the first switch M1, second switch M2, the 3rd switch M3 and driving transistors M4 are in turn-offing cut-off state, in image element circuit 100, cannot form current flowing, so the first capacitor C 1 and the second capacitor C 2 are all by the existing state (the last period is stored in interior separately voltage) keeping separately, intersegmental in the time of T1, the first capacitor C 1 will keep the last period to be stored in the voltage in this first capacitor C 1, same, the second capacitor C 2 also will keep the last period to be stored in the voltage in this second capacitor C 2, and intersegmental in the time of T3, in the T2 period, to be stored in the data voltage Vdata of the first capacitor C 1 constant by remaining on for the first capacitor C 1, and in like manner, also by remaining on, in the T2 period, to be stored in the voltage of the second capacitor C 2 constant for the second capacitor C 2.
Therefore, find out thus, under synchronized transmissions pattern, when data voltage writes after the first electric capacity of any one image element circuit, and wait for when other pixel cells are carried out write operation, utilize the first electric capacity can realize the maintenance effect to this data voltage, to make finally when all pixel cells are during in launching phase, the light-emitting component of each pixel cell can carry out luminous for corresponding data voltage.
In addition, also it is worth mentioning that, what be directly connected with source electrode two electrodes due to the grid of driving transistors is the first electric capacity, so flow through while making light-emitting component luminous, its electric current and the first voltage VDD are also irrelevant, have so just got rid of the first voltage VDD impact on the light-emitting component electric current of flowing through due to the IR pressure drop causing in circuit transmission in prior art.
In sum, utilize image element circuit of the present invention and driving method thereof and active display, the effectively threshold voltage of compensation for drive transistor, get rid of again the impact of problem on light-emitting component glow current such as electron mobility inequality, the IR pressure drop of supply voltage of driving transistors, thereby well improved the uniformity coefficient of active display display brightness.In addition, utilize larger data voltage writing pixel circuit, can avoid especially active display to show low GTG time, data voltage is too small and in data write the period, cannot be full of the first capacitor C 1, and then causes the not good problem of subsequent compensation.
The present invention is described by above-mentioned related embodiment, but above-described embodiment is only for implementing example of the present invention.Must be pointed out that, the embodiment having disclosed does not limit the scope of the invention.On the contrary, the change done without departing from the spirit and scope of the present invention and retouching, all belong to scope of patent protection of the present invention.
Claims (15)
1. an image element circuit, is characterized in that this image element circuit comprises:
Sweep trace;
Data line;
The first power lead;
Second source line;
Light-emitting component, is connected between the first power lead and second source line;
Driving transistors, comprises a grid, and this driving transistors is connected between this light-emitting component and this second source line;
The first switch, comprise the second electrode and the first control electrode that is connected to this sweep trace, and this second electrode connects this data line;
Second switch, comprises the second control electrode that is connected to this sweep trace, and this second switch is connected between this first switch and this grid;
The 3rd switch, is connected between this driving transistors and this light-emitting component;
The first electric capacity, comprises the first end that is connected to this grid and the second end that is connected to this second source line; And
The second electric capacity, comprises the first end that is connected to this sweep trace and the second end that is connected to this grid.
2. image element circuit as claimed in claim 1, is characterized in that this light-emitting component comprises the anode that is connected to this first power lead and the negative electrode that is connected to the 3rd switch the first electrode.
3. image element circuit as claimed in claim 1, is characterized in that this driving transistors also comprises the drain electrode that is connected to the 3rd switch the second electrode and the source electrode that is connected to this second source line.
4. image element circuit as claimed in claim 1, is characterized in that an electrode of this second switch, the first end of this first electric capacity, the second end of this second electric capacity and the grid of this driving transistors are connected in first node.
5. image element circuit as claimed in claim 1, is characterized in that this image element circuit also comprises emission control drive wire, and wherein, the 3rd switch comprises the 3rd control electrode that is connected to this emission control drive wire.
6. image element circuit as claimed in claim 1, is characterized in that this first switch, second switch and the 3rd switch are Thin Film Transistor (TFT).
7. an active display, is characterized in that this active display comprises:
Display panel, this display panel comprises:
A plurality of pixel cells, each this pixel cell comprises image element circuit as claimed in claim 1;
Scan drive cell, in order to provide sweep signal to this image element circuit;
Data-driven unit, in order to provide data-signal to this image element circuit;
Emission control driver element, in order to provide emissioning controling signal to these a plurality of control lines;
The first power supply, in order to apply the first voltage to this first power lead; And
Second source, in order to apply second voltage to this second source line;
Wherein, the magnitude of voltage of second voltage is lower than the magnitude of voltage of this first voltage.
8. active display as claimed in claim 7, is characterized in that this display device also comprises emission control driver element, and wherein, this emission control driver element provides emissioning controling signal to this image element circuit, to control the break-make of the 3rd switch.
9. an image element driving method, is applied to image element circuit as claimed in claim 1, it is characterized in that this driving transistors has a threshold voltage, and this driving method comprises:
A. this first switch of conducting, this second switch and this driving transistors, turn-off the 3rd switch, and the data voltage of the corresponding output of this data line is applied to this first electric capacity, makes this this data voltage of the first capacitance stores;
B. conducting the 3rd switch and this driving transistors, turn-off this first switch, this second switch, and the voltage between this drive transistor gate and source electrode equals the voltage of this first capacitance stores, utilizes the voltage of this first capacitance stores to drive this light-emitting component luminous.
10. driving method as claimed in claim 9, is characterized in that the corresponding output scanning signal of this sweep trace, and wherein, this sweep signal is cyclical signal, and when this sweep signal is during in high level, this first switch and this second switch are in conducting state.
11. driving methods as claimed in claim 9, it is characterized in that this image element circuit also comprises emission control drive wire, the corresponding output of this emission control drive wire control signal, wherein, this control signal is cyclical signal, when this control signal is during in high level, the 3rd switch is in conducting state.
12. driving methods as claimed in claim 9, is characterized in that this data voltage is greater than this threshold voltage.
13. driving methods as claimed in claim 9, it is characterized in that the corresponding output of this sweep trace one periodically variable sweep signal, wherein, in the time that this sweep signal is transformed into low level by high level, this first electric capacity responds a voltage change, and this step B further comprises: the voltage of this first capacitance stores equals the difference of this data voltage and this voltage change.
14. driving methods as claimed in claim 9, is characterized in that before this steps A, also comprising steps A 1: turn-off this first switch, this second switch, the 3rd switch and this driving transistors, this first electric capacity and this second electric capacity all keep existing state.
15. driving methods as claimed in claim 9, it is characterized in that also comprising steps A 2 between this steps A and this step B: turn-off this first switch, this second switch, the 3rd switch and this driving transistors, this first electric capacity keeps being stored in this steps A this data voltage of this first electric capacity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310188057.4A CN104183211A (en) | 2013-05-20 | 2013-05-20 | Pixel circuit, driving method thereof, and light-emitting display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310188057.4A CN104183211A (en) | 2013-05-20 | 2013-05-20 | Pixel circuit, driving method thereof, and light-emitting display |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104183211A true CN104183211A (en) | 2014-12-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310188057.4A Pending CN104183211A (en) | 2013-05-20 | 2013-05-20 | Pixel circuit, driving method thereof, and light-emitting display |
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| CN (1) | CN104183211A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106803416A (en) * | 2015-10-26 | 2017-06-06 | 三星显示有限公司 | Transmitting driver and display device |
| WO2018196378A1 (en) * | 2017-04-28 | 2018-11-01 | 深圳市华星光电半导体显示技术有限公司 | Display panel, pixel driving circuit and driving method therefor |
| CN108831383A (en) * | 2018-06-22 | 2018-11-16 | 昆山国显光电有限公司 | Pixel circuit and its driving method, display panel and display device |
| CN109872692A (en) * | 2017-12-04 | 2019-06-11 | 京东方科技集团股份有限公司 | Pixel circuit and its driving method, display device |
| CN112859991A (en) * | 2021-04-23 | 2021-05-28 | 深圳市拓尔微电子有限责任公司 | Voltage processing circuit and method of controlling voltage processing circuit |
| WO2023010593A1 (en) * | 2021-08-02 | 2023-02-09 | Tcl华星光电技术有限公司 | Pixel driver circuit and mobile terminal |
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2013
- 2013-05-20 CN CN201310188057.4A patent/CN104183211A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106803416A (en) * | 2015-10-26 | 2017-06-06 | 三星显示有限公司 | Transmitting driver and display device |
| CN106803416B (en) * | 2015-10-26 | 2021-06-22 | 三星显示有限公司 | Emission driver and display device |
| WO2018196378A1 (en) * | 2017-04-28 | 2018-11-01 | 深圳市华星光电半导体显示技术有限公司 | Display panel, pixel driving circuit and driving method therefor |
| US10453391B2 (en) | 2017-04-28 | 2019-10-22 | Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd | Display panel, pixel driving circuit, and drving method thereof |
| CN109872692A (en) * | 2017-12-04 | 2019-06-11 | 京东方科技集团股份有限公司 | Pixel circuit and its driving method, display device |
| CN108831383A (en) * | 2018-06-22 | 2018-11-16 | 昆山国显光电有限公司 | Pixel circuit and its driving method, display panel and display device |
| CN112859991A (en) * | 2021-04-23 | 2021-05-28 | 深圳市拓尔微电子有限责任公司 | Voltage processing circuit and method of controlling voltage processing circuit |
| CN112859991B (en) * | 2021-04-23 | 2021-07-30 | 深圳市拓尔微电子有限责任公司 | Voltage processing circuit and method of controlling voltage processing circuit |
| WO2023010593A1 (en) * | 2021-08-02 | 2023-02-09 | Tcl华星光电技术有限公司 | Pixel driver circuit and mobile terminal |
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Application publication date: 20141203 |