CN100514424C - Driver circuit having electromechanical excitation light dipolar body and driving method thereof - Google Patents

Abstract

A driving circuit and for OLED and the driving method is provided, which comprises a switch transistor, a driving TFT, a reservoir capacitance, an OLED and a control transistor. The source and drain of the control transistor controlled by scanning beam are connected with that of the driving TFT. Within one picture frame time, the voltage source is under low level during scanning, while in other times it is under high level. Simultaneously during scanning, the voltage source stores the image data into the reservoir capacitor by the control transistor. When the voltage source is adjusted from low level to high level, the parasitic capacitance of the driving TFT is feed with pulse, which compensates the stability of the time for currency supply and extends the service time of the display panel.

Description

The driving circuit of electromechanical excitation light dipolar body and driving method thereof

Technical field

The present invention relates to a kind of technology of organic electro-luminescent display, particularly relate to the Driving technique of active unit picture element electromechanical excitation light dipolar body, the stable time that electric current is provided, the service time of prolongation display panel.

Background technology

(Organic Light-Emitting Diodes OLED) can be divided into passive type OLED (Passive Matrix OLED according to type of drive to organic electro-luminescent display; PMOLED) with active OLED (Active Matrix OLED; AMOLED).Under the active drive mode, OLED does not need to be driven into very high brightness, can reach preferable life-span performance, and high-resolution demand.Therefore, OLED combination film transistor (TFT) is realized active driving OLED technology, can meet the fluency of playing for picture on the present monitor market, and the more and more higher requirement of resolution, fully represents the above-mentioned advantageous characteristic of OLED.

Because OLED material updating on luminescence efficiency no longer is out of reach in being to use amorphous silicon film transistor (a-Si TFT) element as the platform of driving OLED.The manufacturing process of a-Si TFT is relative with equipment ripe in addition, therefore can provide lower manufacturing cost, reduces the cost of active OLED greatly.

Though a-Si TFT has absolute predominance cheaply, but if a-Si TFT will be applied on the driving OLED, still have a technical difficult problem to overcome, wherein have two targets to reach: one for improving the stability (Stability) of a-Si TFT element, and two for increasing the current driving ability (Capability) of a-SiTFT element.

The conventional ADS driving circuit engineering is the synoptic diagram of the unit picture element driving circuit of conventional display panels as shown in Figure 1.Per unit pixel (Pixel) is the circuit structure of 2T1C (electric capacity of two TFT transistor AND gates), the switch and the driving transistors that use are all N passage (N-channel) a-Si TFTs, wherein the drain electrode of driving transistors 12 is connected to voltage source V dd, source electrode is connected to the anode of organic light emitting diode 14, and the negative electrode of organic light emitting diode 14 then is coupled to the electronegative potential Vss (for example ground connection becomes 0 current potential) of system.In addition, the grid of switching transistor 11 inserts sweep signal Vscan, source electrode incoming data signal Vdata, and the drain electrode of switching transistor 11 is coupled to the grid of driving transistors 12 and an end of storage capacitors 13, and the other end of storage capacitors 13 then is coupled to reference potential Vref.

The elemental motion principle is: after 11 conductings of sweep signal Vscan gauge tap transistor, can make the data-signal Vdata that represents the image gray scale data on the data line input to an end of storage capacitors 13, be used for the grid of controlling and driving transistor 12, and driving transistors 12 can produce different grid-source voltage Vgs (being Vg-Vs) under different grid voltage Vg, makes driving transistors 12 produce the drive current I of different sizes _DIf will make driving transistors 12 can produce drive current I _D, then the grid of driving transistors 12-source voltage Vgs must be greater than the critical voltage value Vth of driving transistors 12.

Yet above-mentioned unit picture element circuit is in operation during long-time situation, the driving voltage V of organic light emitting diode 14 _OLEDCan become big along with the time, as shown in Figure 2.Therefore can cause the bias condition of this driving transistors 12 to reduce, and then reduce drive current I _DOutput, the magnitude of current of this organic light emitting diode 14 that causes indirectly flowing through reduces, as shown in Figure 3.This organic light emitting diode 14 and drive current I _DRelational expression can be expressed as follows:

$I_D=\frac{1}{2}k{(\mathrm{Vgs}-\mathrm{Vth})}^2---\left(1\right)$

$I_D=\frac{1}{2}k{(\mathrm{Vg}-\mathrm{Vs}-\mathrm{Vth})}^2---\left(2\right)$

V again _S=V _OLED+ V _SS(3)

$I_D=\frac{1}{2}k{(\mathrm{Vg}-V_{\mathrm{OLED}}-\mathrm{Vss}-\mathrm{Vth})}^2---\left(4\right)$

Wherein, k is the characteristic constant of thin film transistor (TFT), Vg=Vdata, and V _OLEDFor striding across the driving voltage of organic light emitting diode 14.Can find out by above-mentioned formula (4), as driving voltage V _OLEDWhen becoming big with long-time unlatching, the drive current I of this organic light emitting diode 14 of flowing through _DDiminish thereupon, and then influence the luminescent condition of organic light emitting diode 14, brightness decreases, and influences display quality.

In addition, if when aforementioned type of drive is applied in the driving circuit that a-Si TFT formed, when driving transistors 12 is opened because of long-term, will on the grid-source voltage Vgs of driving transistors 12, continue to set up voltage greater than zero, promptly for driving transistors 12, grid-source voltage Vgs is the situation that always maintains positive bias (Positive Stress), this can cause the deterioration of a-Si TFT element characteristic, the critical voltage value Vth of driving transistors 12 can can't keep initial value and along with the time increases, produce forward migration, can't keep long steady current output, as shown in Figure 4.When critical voltage value Vth increases and this driving voltage V _OLEDIdentical, the drive current I of this organic light emitting diode 14 of flowing through _DDiminish thereupon, make this organic light emitting diode 14 can't keep original brightness, influence display quality.

For solving the shortcoming of above-mentioned traditional unit picture element driving circuit, U.S. Pat 6,677, disclosed a kind of driving circuit of unit picture element in 713, its circuit structure is the collocation that utilizes two switching transistors (first switching transistor 21, second switch transistor 22) and a driving transistors 23 and a storage capacitors 24, drive the combination of organic light emitting diode 25 as this, as shown in Figure 5.Wherein the grid of this first switching transistor 21 receives the first sweep frequency VscanA; And the grid of this second switch transistor 22 receives the second sweep frequency VscanB, and the drain electrode of this second switch transistor 22 receives low-voltage Vref2.And this second sweep frequency VscanB is identical with this first sweep frequency VscanA, but this second sweep frequency VscanB has Δ T time delay (at a picture frame in the time) to this first sweep frequency VscanA, as shown in Figure 6.

This patent mainly is to increase switching transistor, carries out the action of negative pressure tempering (Negative Bias Annealing) by the mode of signal controlling, and the critical voltage value Vth characteristic variation problem of this driving transistors 23 can be improved.But in this patented technology, carry out characteristic when improving when increasing by 22 pairs of these driving transistorss 23 of this second switch transistor, a scan signal line (VscanB) must be increased and low voltage lines (Vref2) is controlled, cabling in the single pixel is increased, cause the reduction of pixel aperture ratio, display quality is descended.This patent and reckon without the driving voltage V of this organic light emitting diode 25 in addition _OLEDThe characteristic variations influence increases this driving voltage V when the demonstration time _OLEDCan become big along with the time, and then cause drive current to descend, luminosity is and then descended.

In addition, U.S. Pat 6,680,580 have also disclosed a kind of driving circuit of unit picture element, and as shown in Figure 7, its circuit structure has increased oxide-semiconductor control transistors 32 in addition except that switching transistor 31, driving transistors 33 and the storage capacitors 34 of traditional structure.The source electrode of this oxide-semiconductor control transistors 32 is received common voltage Vcom, and drain electrode then is connected to the anode tap of this organic light emitting diode 35.And the grid of this switching transistor 31 and this oxide-semiconductor control transistors 32 receives this sweep frequency Vscan simultaneously.

Wherein this common voltage Vcom comprises accurate position of high voltage and the accurate position of low-voltage, and as shown in Figure 8, with a frequency alternate, and the high levle of this common voltage Vcom is bigger than the electronegative potential Vss of system, and low level is littler than the electronegative potential Vss of system.When switching transistor 31 and this oxide-semiconductor control transistors 32 are controlled simultaneously by this sweep frequency Vscan and when opening, this data-signal Vdata can import image data voltage with one that closes in the negative voltage.When common voltage Vcom was in low level, it closed the negative voltage input, in order to close this driving transistors 33 and this organic light emitting diode 35.

This patent mainly is to utilize the adding of oxide-semiconductor control transistors 32, and common voltage Vcom signal is imposed on the source electrode of this driving transistors 33, avoids the grid-source terminal cross-pressure of this driving transistors 33 and the driving voltage V of organic light emitting diode 35 thus _OLEDCharacteristic variations.Also utilize a picture frame time, carry out the demonstration of image data, utilize the next picture frame time again, the driving transistors on all panels 33 is carried out the negative pressure tempering, with the problem of the critical voltage value Vth flutter of this driving transistors 33 of effective inhibition.

But, though this patent improve driving voltage V _OLEDCharacteristic variations is for the influence of image element circuit reliability, but when oxide-semiconductor control transistors 32 is unlocked, the source voltage Vs of this driving transistors 33 and can't be equal to common voltage Vcom, main cause is that the impedance problems between the leakage-source electrode of this oxide-semiconductor control transistors 32 must be considered.Because the electric current of this driving transistors 33 is directed at this moment changing and flow to this oxide-semiconductor control transistors 32, if the component size of this oxide-semiconductor control transistors 32 is too small, then impedance problems becomes seriously, promptly can cause this source voltage Vs can't be equal to common voltage Vcom.And different electric currents are when flowing through this oxide-semiconductor control transistors 32, and this source voltage Vs also can be different.Though can strengthen the problem that the component size of this oxide-semiconductor control transistors 32 can solve the accurate position of node Vs, can reduce this aperture ratio of pixels like this, cause luminosity to be affected.And, when this patent suppresses the critical voltage value Vth variation problem of this driving transistors 33, need utilize a picture frame time to carry out the negative pressure tempering, show image brightness and quality can descend like this.

U.S. Pat 6,756, the circuit structure in 741 is the collocation that utilizes three transistors and a storage capacitors equally, to drive organic light emitting diode, as shown in Figure 9.This first switching transistor 41 inserts this sweep signal Vscan simultaneously with the grid of second switch transistor 42; This first switching transistor 41 is then received voltage source V dd together with the drain electrode of driving transistors 43.And the source electrode of this first switching transistor 41 then is connected to the grid of this driving transistors 43 and an end of this storage capacitors 44; The source electrode of this second switch transistor 42 then inserts this data-signal Vdata; These storage capacitors 44 other ends then join with the drain electrode of this second switch transistor 42, the source electrode of this driving transistors 43 and the anode tap of organic light emitting diode 45.

This patent mainly is the use by this first and second switching transistor 41,42, allow cross-pressure at the Vgs bias voltage=Vdd-Vdata at driving transistors 43 two ends, this driving transistors 43 can produce drive currents this organic light emitting diode 45 of flowing through and carried out luminous action this moment.Thus, can avoid driving voltage V _OLEDThe influence that the characteristic variation is caused.

But, when this second switch transistor 42 when sweep signal Vscan is high levle (High), this data-signal Vdata transmits the end of image data to this storage capacitors 44.At this moment, second switch transistor 42 and organic light emitting diode 45 all are resistive load, when quiescent current continues by this second switch transistor 42, can cause the image data of actual transmission to have error to exist, cause input image data and show image result to have different situations and produce to these storage capacitors 44 ends.And this patent is not improved the critical voltage value Vth variation problem of this driving transistors 43, and the critical voltage value Vth of driving transistors 43 can can't keep initial value and along with the time increases, produce forward migration, can't keep long steady current output.

Summary of the invention

In order to solve the defective that exists in the above-mentioned prior art, the invention provides a kind of driving circuit and control method thereof, be suitable for using amorphous silicon film transistor as driving purposes to organic light emitting diode.Solve under organic light-emittingdiode is working long hours, the increase of this driving voltage characteristic makes this driving voltage can keep certain value; And, when avoiding amorphous silicon film transistor (a-Si TFT) substrate to be used as the panel circuit design, this a-Si TFT element works long hours and understands the characteristic of rapid deterioration, keeps the stable of the long-time electric current output of a-Si TFT element, and the prolongation panel life-span is also improved display quality.

Driving circuit according to electromechanical excitation light dipolar body of the present invention comprises: switching transistor has the grid that is coupled to sweep trace, the source electrode that is coupled to data line and drain electrode; Oxide-semiconductor control transistors has grid that is coupled to described sweep trace and the drain electrode that is coupled to voltage source; Driving transistors has the grid that is connected with the drain electrode of described switching transistor, the drain electrode that is coupled to described voltage source and source electrode; The source electrode that storage capacitors, one end are coupled between the grid of the drain electrode of described switching transistor and described driving transistors, the other end is coupled to described driving transistors; And organic light emitting diode, the negative electrode that has the anode of the source electrode that is coupled to described driving transistors and be coupled to the electronegative potential of driving circuit.

Driving method according to the driving circuit of electromechanical excitation light dipolar body of the present invention, be to be a time quantum with a picture frame, when sweep signal is high levle, then this switching transistor and oxide-semiconductor control transistors can be unlocked simultaneously, at this moment, data signal line can be imported image data to this storage capacitors one end, and this voltage source transmits the end of low level to this storage capacitors, and this low level must avoid organic light emitting diode to carry out luminous maloperation in the data storing process; Next, when sweep signal was low level, this storage capacitors had been maintained the data-signal of this image gray scale value, made the data-signal of this image gray scale value can not have error to occur with the characteristic variation of this organic light emitting diode.Through after a while, this voltage source can rise to high levle by low level, and this moment, this driving transistors began to provide electric current this organic light emitting diode of flowing through, and made this organic light emitting diode carry out luminous action.

When the present invention utilizes this voltage source to be increased to high levle by low level, stray capacitance to this driving transistors produces power supply pulse wave feed-in (Power Pulse Feed-through), compensate the time stability of this driving transistors supplying electric current thus, prolong the service time of display panel.

Description of drawings

Fig. 1 is the synoptic diagram of the unit picture element driving circuit of conventional display panels.

Fig. 2 illustrates the variation of the driving voltage of Fig. 1 with service time.

Fig. 3 illustrates the variation of the drive current of Fig. 1 with service time.

Fig. 4 illustrates the critical voltage of driving transistors of Fig. 1 with the variation of service time.

Fig. 5 is a U.S. Pat 6,677, the driving circuit figure in 713 unit picture elements.

Fig. 6 illustrates the sequential relationship of the sweep frequency of Fig. 5.

Fig. 7 is a U.S. Pat 6,680, the driving circuit figure in 580 unit picture elements.

Fig. 8 illustrates the sequential control relation that Fig. 7 cooperates the sequential of input voltage.

Fig. 9 is a U.S. Pat 6,756, the driving circuit figure in 740 unit picture elements.

Figure 10 is the driving circuit figure in the unit picture element of the present invention.

Figure 11 is the corresponding control signal sequential of a present invention synoptic diagram.

Figure 12 is a drives structure synoptic diagram of the present invention.

Figure 13 is the stray capacitance synoptic diagram of circuit component of the present invention.

Embodiment

Relevant detailed content of the present invention and technical descriptioon are as follows referring now to description of drawings:

The invention provides the design of a kind of driving electromechanical excitation light dipolar body (diode), can be applicable to combine the active drive organic electro-luminescent display (AMOLED) of amorphous silicon film transistor (a-Si TFT) and organic light emitting diode (OLED).Please refer to Figure 10, it is the circuit structure of unit picture element of the present invention, this circuit structure comprises: switching transistor 110, and the source terminal of this switching transistor 110 and data line 220 couple, and its drain electrode end is coupled to an end of the gate terminal and the storage capacitors 140 of driving transistors 130.The gate terminal of this switching transistor 110 is to join with the gate terminal of sweep trace 210 and oxide-semiconductor control transistors 120.And the drain electrode end of the drain electrode end of this driving transistors 130 and this oxide-semiconductor control transistors 120 is connected to a voltage source V dd jointly.The other end of the source terminal of the anode tap of the source terminal of this driving transistors 130 and organic light emitting diode 150, oxide-semiconductor control transistors 120 and this storage capacitors 140 is engaged in a node jointly.The cathode terminal of this organic light emitting diode 150 is connected to the electronegative potential Vss of driving circuit.

Wherein this switching transistor 110, oxide-semiconductor control transistors 120 are N conductivity type (N-type) thin film transistor (TFT)s with brilliant 130 bodies of driving electricity.

Type of drive of the present invention please refer to Figure 11, is the control signal sequential relationship that cooperates input according to the circuit of Figure 10.The operation of display is to be a time quantum with a picture frame, having some corresponding scanning line 210 in picture frame is activated, this sweep trace 210 cooperates the size of picture frame to provide sweep signal Vscan with a frequency, this sweep signal Vscan is input into the grid of this switching transistor 110 and oxide-semiconductor control transistors 120, opens these transistors 110,120 with control.When sweep signal Vscan is high levle, this moment, this switching transistor 110 and oxide-semiconductor control transistors 120 can be unlocked simultaneously, and the data-signal Vdata that has the different GTG values of image on this data line 220 can input to an end of this storage capacitors 140 by this switching transistor 110.On the other hand, this voltage source V dd transmits the other end (the just anode tap of the source terminal of this oxide-semiconductor control transistors 120, driving transistors 130 and this organic light emitting diode 150) of the accurate position of low-voltage to this storage capacitors 140 by this oxide-semiconductor control transistors 120, and the accurate position stage of the low-voltage of this voltage source V dd is to be used for avoiding this organic light emitting diode 150 to carry out luminous maloperation at the image data storage process.Next, when sweep signal Vscan is low level, this switching transistor 110 and oxide-semiconductor control transistors 120 all can be closed condition, but, this moment, this storage capacitors 140 was maintained the data-signal Vdata of this image gray scale value, made the data-signal Vdata of this image gray scale value can not have error to occur with the characteristic variation of this organic light emitting diode 150.Through after a while, this voltage source V dd can rise to the accurate position of high voltage by the accurate position of low-voltage, and then this moment, this driving transistors 130 began to provide electric current I _DThis organic light emitting diode 150 of flowing through makes this organic light emitting diode 150 carry out luminous action.

Wherein the accurate position of the high voltage of this voltage source V dd is than the electronegative potential height of this driving circuit, and accurate of the low-voltage of this voltage source V dd equates with the electronegative potential of this driving circuit or be low than the electronegative potential of this driving circuit.

Please again in conjunction with Figure 12, drives structure of the present invention is characterised in that a picture frame time is divided into two parts, promptly the exchange frequency of the accurate position of the low-voltage of this voltage source V dd and accurate of high voltage is to be to change one-period with a picture frame, to drive the not luminous/luminance of this organic light emitting diode, reach the picture frame operated in anti-phase.And the proportionate relationship of the accurate position of this low-voltage and the accurate position of high voltage writes with the proportionate relationship of picture demonstration time with data and to equate.The last stage of picture frame is used for when this voltage source V dd is the accurate position of low-voltage for scanning stage Ts, and all pixels deposit the data-signal Vdata of required image in this storage capacitors 140 on the display panel; Its after-stage is demonstration stage Td, when this voltage source V dd is the accurate position of high voltage, makes all pixels of panel begin to carry out luminous action.

Under the drives structure pattern that the present invention proposes, this voltage source V dd be the accurate position of low-voltage in the scan period of display panel, and is finishing the scan period when entering shinny cycle, and this voltage source V dd can become accurate of high voltage from the accurate position of low-voltage.In the voltage change process of this voltage source V dd, because circuit component itself has stray capacitance (C _Gd1, C _Gd3And C _OLED) exist, as shown in figure 13.And it is luminous that this driving transistors 130 provides enough big drive current ID to carry out for this organic light emitting diode 150, so that the component size of this driving transistors 130 can be designed to be is bigger, causes the parasitic capacitance value C of this driving transistors 130 _Gd3Also become big thereupon, cause the gate terminal Coupling Potential of this driving transistors 130 to increase, thus former should driving transistors 130 gate terminal and this storage capacitors 140 couple the current potential V at place _NWith added value " forward migration amount Δ V _N".So the TFT element can produce down the problem of critical voltage value Vth forward migration working long hours in the former conventional circuit structure, the forward migration amount Δ V that can be produced by this voltage source V dd among the present invention _NBe used as the amount of suppression of critical voltage value Vth forward migration, and then prolong the life-span and the display quality of panel.Its forward migration amount Δ V _NIt is as follows to derive:

Q _charge＝C _gd1(V _N-Vg ₁₁₀)+C _gd3(V _N-Vdd)+C ₁₄₀(V _N-V _P)

Q _dicharge＝C _gd1(V _N’-Vg ₁₁₀’)+C _gd3(V _N’-Vdd’)+C ₁₄₀(V _N’-V _P’)

Q again _Charge=Q _Dicharge

∴C _gd1V _N-C _gd1Vg ₁₁₀+C _gd3V _N-C _gd3Vdd+C ₁₄₀V _N-C ₁₄₀V _P＝C _gd1V _N’-C _gd1Vg ₁₁₀’+C _gd3V _N’-C _gd3Vdd+C ₁₄₀V _N’-C ₁₄₀V _P’

$\&DoubleRightArrow;C_{\mathrm{gd}1}\mathrm{\&Delta;}{V}_N-C_{\mathrm{gd}1}\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="110"\; label="Vg"\; filenames="C200610128680E00202.png"\; state="\{\{state\}\}">Vg</figure-callout>}}_{110}+C_{\mathrm{gd}3}\mathrm{\&Delta;}{V}_N-C_{\mathrm{gd}3}\mathrm{\&Delta;Vdd}+{\mathrm{<figure-callout\; id="140"\; label="C"\; filenames="C200610128680E00202.png"\; state="\{\{state\}\}">C</figure-callout>}}_{140}\mathrm{\&Delta;}{V}_N$

$-{\mathrm{<figure-callout\; id="140"\; label="C"\; filenames="C200610128680E00202.png"\; state="\{\{state\}\}">C</figure-callout>}}_{140}\mathrm{\&Delta;}{V}_P=0$

$\&DoubleRightArrow;\mathrm{\&Delta;}{V}_N=(C_{\mathrm{gd}1}\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="110"\; label="Vg"\; filenames="C200610128680E00202.png"\; state="\{\{state\}\}">Vg</figure-callout>}}_{110}+C_{\mathrm{gd}3}\mathrm{\&Delta;Vdd}+{\mathrm{<figure-callout\; id="140"\; label="C"\; filenames="C200610128680E00202.png"\; state="\{\{state\}\}">C</figure-callout>}}_{140}\mathrm{\&Delta;}{V}_P)/(C_{\mathrm{gd}1}+C_{\mathrm{gd}3}$

$+C_{140})$

C wherein _Gd1Be the stray capacitance of this switching transistor 110, C _Gd3Be the stray capacitance of this driving transistors 130, V _NBe the current potential of these driving transistors 130 gate terminal, V _PBe the current potential of these driving transistors 130 source terminals, C ₁₄₀Be this storage capacitors 140.And, consider critical voltage value offset Vth and forward migration amount Δ V when simultaneously _N, and substitution drive current relational expression (formula (4)), can get

$I_D=\frac{1}{2}k{(\mathrm{Vgs}+\mathrm{\&Delta;}{V}_N-(V_{\mathrm{th}}+\mathrm{\&Delta;}{V}_{\mathrm{th}}))}^2$

Along with the increase of service time, though the critical voltage value Vth of this driving transistors 130 can increase,, can increase the size of voltage service time gradually with panel as long as this voltage source V dd is carried out external control, Δ V is provided _NRecruitment.Wherein, this Δ V _NRecruitment can be similar to this critical voltage value forward migration value Δ Vth, can reach reduction increases the institute's display brightness that causes decline because of critical voltage value Vth phenomenon.

Comprehensively above-mentioned, the present invention is at the low level signal that transmits this voltage source V dd during to the source terminal of this driving transistors 130, this driving transistors 130 does not have quiescent current and produces, therefore, impedance problems between these oxide-semiconductor control transistors 120 leakage-source electrodes, losing true feelings shape in the time of can't making this low level signal deliver to the source terminal of this driving transistors 130 produces, so do not need to consider the component size size of this oxide-semiconductor control transistors 120 in the design, therefore, compare with the circuit that prior art is carried, the 3rd transistor that the present invention adds can minimize, and need not consider impedance factors, to improve or to keep aperture ratio of pixels.On the other hand, the present invention is on the compensation way of a-Si TFT element critical voltage value Vth forward migration, be to utilize the part picture frame time to do scanning motion, intercropping display operation during the part picture frame, when power supply line is increased to the high levle in shinny cycle by the low level of scan period, by the stray capacitance C of this driving transistors 130 _Gd3, storage capacitors 140 is produced power supply pulse wave feed-in (PowerPulse Feed-through), the current potential forward migration amount Δ V that is produced _NValue.Can compensate the time stability of these driving transistors 130 supplying electric currents, prolong the service time of display panel.

The present invention only needs the timing variations of this voltage source V of modulation dd, can reach simultaneously to avoid organic light emitting diode characteristic variation influence, and avoid display brightness to be affected.And aspect the critical voltage value Vth forward migration of compensation a-Si TFT, do not need to add extra control signal wire, do not occupy extra light-emitting area, influence the viewing area aperture opening ratio so the present invention does not have signal wire.

The above is the preferred embodiments of the present invention only, is not limited to the present invention.In the above-described embodiments, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (7)

1. the driving circuit of an electromechanical excitation light dipolar body is characterized in that, described driving circuit comprises:

Switching transistor (110) has: grid is coupled to sweep trace (210); Source electrode is coupled to data line (220); And drain electrode;

Oxide-semiconductor control transistors (120) has: grid is coupled to described sweep trace (210); And drain electrode, be coupled to voltage source (Vdd);

Driving transistors (130) has: grid is connected with the drain electrode of described switching transistor (110); Drain electrode is coupled to described voltage source (Vdd), and source electrode;

The source electrode that storage capacitors (140), one end are coupled between the grid of the drain electrode of described switching transistor (110) and described driving transistors (130), the other end is coupled to described driving transistors (130); And

Organic light emitting diode (150) has: anode is coupled to the source electrode of described driving transistors (130); And negative electrode, be coupled to the electronegative potential (Vss) of driving circuit.

2. driving circuit according to claim 1 is characterized in that, described switching transistor (110), oxide-semiconductor control transistors (120) are respectively the N conductivity type thin-film transistor with driving transistors (130).

3. the driving method of an electromechanical excitation light dipolar body is characterized in that:

The circuit that described driving method drives comprises voltage source (Vdd), and described voltage source has accurate position of low-voltage and the accurate position of high voltage, and accurate position is with a frequency alternate;

Wherein, when described voltage source (Vdd) is in the accurate position of low-voltage, switching transistor (110) is scanned signal (Vscan) with oxide-semiconductor control transistors (120) and controls simultaneously and open, make data-signal (Vdata) be stored to an end of storage capacitors (140), and the other end of described storage capacitors (140) is the accurate position of low-voltage of described voltage source (Vdd), makes organic light emitting diode (150) not luminous;

When described voltage source (Vdd) was in the accurate position of high voltage, the accurate position of described high voltage drove organic light emitting diode (150) and carries out luminous.

4. driving method according to claim 3, it is characterized in that, the exchange frequency of the accurate position of the low-voltage of described voltage source (Vdd) and accurate of high voltage is to be to change one-period with a picture frame, to drive the not luminous/luminance of described organic light emitting diode (150), reach the picture frame operated in anti-phase.

5. driving method according to claim 4 is characterized in that, the proportionate relationship of the accurate position of the low-voltage of described voltage source (Vdd) and the accurate position of high voltage writes with the proportionate relationship of picture demonstration time with data and to equate.

6. driving method according to claim 3 is characterized in that, the accurate position of the high voltage of described voltage source (Vdd) is higher than the electronegative potential of described driving circuit, and the accurate position of the low-voltage of described voltage source (Vdd) equates with the electronegative potential of described driving circuit.

7. driving method according to claim 3 is characterized in that, the accurate position of the high voltage of described voltage source (Vdd) is higher than the electronegative potential of described driving circuit, and the accurate position of the low-voltage of described voltage source (Vdd) is lower than the electronegative potential of described driving circuit.

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