CN103606351B - Active matrix organic light-emitting diode pixel-driving circuit and driving method thereof - Google Patents

Active matrix organic light-emitting diode pixel-driving circuit and driving method thereof Download PDF

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CN103606351B
CN103606351B CN201310629215.5A CN201310629215A CN103606351B CN 103606351 B CN103606351 B CN 103606351B CN 201310629215 A CN201310629215 A CN 201310629215A CN 103606351 B CN103606351 B CN 103606351B
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transistor
emitting diode
organic light
driving transistors
electrode
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CN201310629215.5A
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CN103606351A (en
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刘超
丁毅岭
方娜
田犁
汪宁
章琦
汪辉
封松林
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中国科学院上海高等研究院
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Abstract

The invention provides active matrix organic light-emitting diode pixel-driving circuit and driving method thereof, this driving circuit comprises: the first transistor, transistor seconds, third transistor, driving transistors, building-out capacitor and Organic Light Emitting Diode, wherein, described driving transistors has an embedded tunneling field-effect pipe, the threshold voltage of this driving transistors can be changed by this tunneling field-effect pipe, and then change the size of drive current, thus the unevenness that not only compensate between each pixel driven transistor threshold voltage, also reduce the area of single pixel, be conducive to the raising of aperture opening ratio.

Description

Active matrix organic light-emitting diode pixel-driving circuit and driving method thereof

Technical field

The present invention relates to the pixel driver technology of light emitting diode indicator, particularly relate to active matrix organic light-emitting diode pixel-driving circuit and driving method thereof.

Background technology

Building-out capacitor active matrix organic light-emitting diode (ActiveMatrix/OrganicLightEmittingDiode, AMOLED) display is one of focus of current flat-panel monitor research field, compared with traditional OLED, active matrix organic light-emitting diode has that low energy consumption, wide viewing angle, response are fast, contrast advantages of higher.

The thin film transistor (TFT) adopted in the pixel of active matrix organic light-emitting diode is mainly divided into hydrogenation non crystal silicon film transistor (a-Si:HTFT) and low-temperature polysilicon film transistor (LTPSTFT) two kinds, due to the difference of material nature, the carrier mobility of a-Si:HTFT is lower than LTPSTFT.Compared with adopting the pixel of LTPSTFT, adopt the pixel of a-Si:HTFT to need to strengthen device size, and improve driving voltage, the driving effect identical with LTPSTFT could be realized, but, the aperture opening ratio of pixel and device lifetime also can be caused thus to reduce.Therefore, the active matrix organic light-emitting diode device of LTPSTFT is adopted to have obvious advantage.

Due to the deviation of actual manufacturing process, the threshold voltage of the driving tube TFT in pixel and carrier mobility are also incomplete same.If do not adopt compensation technique, the difference of pixel driver device parameter will cause display brightness of image uneven, thus cause the decline of image displaying quality.In addition, along with the accumulation of working time, device will be aging, and the threshold voltage of drive TFT can increase, and under identical voltage signal, the drive current of drive TFT diminishes, thus the overall brightness of effect diagram picture.

In order to solve the problem, there has been proposed a variety of compensation scheme, as one of compensation scheme comparatively typical in prior art, application number is 201010522409.1, name is called that the Chinese patent of " pixel-driving circuit of active organic electroluminescent display and driving method thereof " proposes a kind of pixel-driving circuit of compensating action, Fig. 1 and Fig. 2 is respectively active matrix organic light-emitting diode pixel-driving circuit structural representation and corresponding driver' s timing schematic diagram in prior art.As Fig. 1, shown in Fig. 2, in the program, active matrix organic light-emitting diode pixel-driving circuit comprises a driving transistors T2, four switching transistor T1, T3, T4, T5, a coupling capacitance C1, a building-out capacitor C2 and Organic Light Emitting Diode OLED, the first transistor T1 controls the grid write grayscale data voltage Vdata that coupling capacitance C1 is driving transistors T2, driving transistors T2 is for driving Organic Light Emitting Diode OLED luminous, third transistor T3 provides charging path by the 4th transistor T4, discharge path is provided by driving transistors T2, it is luminous that 4th transistor T4 controls Organic Light Emitting Diode OLED by driving transistors T2, 5th transistor T5 provides discharge path, avoid Organic Light Emitting Diode OLED luminous at threshold voltage memory phase.

The pixel-driving circuit that the program provides can solve the unevenness of each pixel driving transistors of active matrix organic light-emitting diode T2 threshold voltage effectively, and Organic Light Emitting Diode OLED causes the degeneration of cut-in voltage along with the working time increases.But this dot structure is comparatively complicated, be unfavorable for the raising of its aperture opening ratio, especially the area that two electric capacity in pixel occupy is comparatively large, limits the miniaturization of pixel to a great extent, is unfavorable for the further raising of active matrix organic light emitting diode display integrated level.

Summary of the invention

The shortcoming of prior art in view of the above, the object of the present invention is to provide active matrix organic light emitting diode display pixel-driving circuit and driving method thereof, uneven for solving active matrix organic light emitting diode display pixel driver device threshold voltage in prior art, and dot structure is complicated, is unfavorable for the problem that its aperture opening ratio improves.

For achieving the above object and other relevant objects, the invention provides active matrix organic light-emitting diode pixel-driving circuit, described circuit comprises: the first transistor, transistor seconds, third transistor, driving transistors, building-out capacitor and Organic Light Emitting Diode, wherein:

The grid of described the first transistor connects the first scan control signal, and the first electrode is connected with the drain electrode of driving transistors with the second electrode of third transistor, and the second electrode connects the first end of building-out capacitor and the control gate of driving transistors;

The grid of described transistor seconds connects the second scan control signal, and the second electrode connects the second voltage signal, and the first electrode is connected with the source electrode of driving transistors with the first pole of Organic Light Emitting Diode, the second end of building-out capacitor;

The grid sending and receiving optical control signal of described third transistor, the first electrode connects the first voltage signal;

Second pole of described Organic Light Emitting Diode connects low supply voltage signal.

Preferably, described second voltage signal is equal with low supply voltage signal.

Preferably, described the first transistor is symmetrical structure, and its first electrode, the second electrode are interchangeable; Second, third transistor described is symmetrical structure or unsymmetric structure.

Preferably, described first electrode is drain electrode, and the second electrode is source electrode, and described the first transistor, transistor seconds and third transistor are N-type, the first very anode of described Organic Light Emitting Diode.

Preferably, described first electrode is source electrode, and the second electrode is drain electrode, and described the first transistor, transistor seconds and third transistor are P type, the first very negative electrode of described Organic Light Emitting Diode.

Preferably, described the first transistor, transistor seconds and third transistor are selected from any one in polycrystalline SiTFT, amorphous silicon film transistor, Zinc oxide based film transistor and OTFT.

Preferably, described driving transistors, except control gate, source electrode, drain electrode, also comprises half floating boom, and the doping type of described half floating boom and source electrode, drain contrary; Described half floating boom contacts with drain doping region and forms an embedded type diode; Described control gate to extend to above drain doping region and covers its surface, and described half floating boom, drain doping region and the control gate extended to above drain doping region form an embedded tunneling field-effect transistor.

Correspondingly, present invention also offers the driving method of above-mentioned active matrix organic light emitting diode display pixel-driving circuit, the method comprises:

Reseting stage: transistor seconds and third transistor conducting, the first transistor turns off, and driving transistors is discharged by third transistor;

Pre-charging stage: the equal conducting of the first transistor, transistor seconds and third transistor, the first voltage signal is charged to building-out capacitor by the first transistor and third transistor;

Threshold voltage memory phase: the first transistor and transistor seconds conducting, third transistor turns off, building-out capacitor is by driving transistors and transistor seconds electric discharge, and when having discharged, the voltage at described building-out capacitor two ends is the initial threshold voltage of driving transistors;

The charge storage stage: the first transistor turns off, transistor seconds and third transistor conducting, second voltage signal acts on the control gate of driving transistors through transistor seconds and building-out capacitor, and by charge storage in half floating boom of driving transistors, the threshold voltage of driving transistors becomes Second Threshold voltage;

Glow phase: the first transistor and transistor seconds turn off, third transistor conducting, and driving transistors drives organic light-emitting diode.

Preferably, at reseting stage, the diode positively biased between half floating boom of driving transistors and drain electrode, is discharged by half floating boom of third transistor to driving transistors.

Preferably, in pre-charging stage, the both end voltage after building-out capacitor charging is higher than the initial threshold voltage of driving transistors.

Preferably, in the charge storage stage, embedded tunneling field-effect transistor conducting in driving transistors, second voltage signal acts on the source electrode of driving transistors through transistor seconds, and through the coupling of building-out capacitor to the control gate of driving transistors, by charge storage in half floating boom of driving transistors, half floating boom of driving transistors is charged, after charging complete, the threshold voltage of driving transistors becomes Second Threshold voltage.

Preferably, in glow phase, the voltage difference at building-out capacitor two ends is the initial threshold voltage of driving transistors and remains unchanged, and the luminosity of Organic Light Emitting Diode remains unchanged within the time of a two field picture.

Preferably, in reseting stage, pre-charging stage, threshold voltage memory phase and charge storage stage, the magnitude of voltage of the second voltage signal is less than the second pole tension of Organic Light Emitting Diode and the forward voltage sum of Organic Light Emitting Diode.

As mentioned above, active matrix organic light emitting diode display pixel-driving circuit of the present invention and driving method thereof, have following beneficial effect:

First, in the present invention in active matrix organic light-emitting diode pixel-driving circuit, adopt the driving transistors with an embedded diode/tunneling field-effect transistor, realize embedded diode/tunneling field-effect transistor by the control gate and drain voltage controlling this driving transistors to be biased, electric current is made to flow to half floating boom from drain electrode, charge storage in half floating boom of driving transistors, thus changes the threshold voltage of driving transistors.Because initial threshold voltage is coupled on driving transistors stored in building-out capacitor by the present invention in advance, during organic light-emitting diode, drive current I driveonly with threshold voltage variation amount Δ V threlevant, and have nothing to do with the initial threshold voltage of driving transistors, thus the impact that the driving transistors initial threshold voltage unevenness avoiding each dot structure in active matrix organic light emitting diode display is brought organic light-emitting diode, the homogeneity of display brightness of image is improved, and active matrix organic light-emitting diode display effect improves.

Secondly, compared with pixel-driving circuit structure each in prior art, in active matrix organic light-emitting diode pixel-driving circuit provided by the invention and driving method, all only adopt the unevenness between each pixel driven transistor threshold voltage of single capacitance compensation, improve the uniformity coefficient of display display, thus improve the display effect of active matrix organic light emitting diode display further.Meanwhile, compared with prior art, in active matrix organic light-emitting diode pixel-driving circuit provided by the invention and driving method, only comprise a capacitance structure, realize driving and signal storage function with driving transistors simultaneously, decrease electric capacity quantity required in driving circuit, further reduce elemental area, greatly simplify dot structure, be conducive to the raising of its aperture opening ratio simultaneously, the dot structure of high integration can be realized.

Accompanying drawing explanation

Fig. 1 is shown as the schematic diagram of the pixel-driving circuit of active organic electroluminescent display in prior art.

Fig. 2 is shown as the schematic diagram of the driver' s timing of the pixel-driving circuit of active organic electroluminescent display in prior art.

Fig. 3 is shown as the schematic diagram of driving transistors in the present invention.

Fig. 4 is shown as the gate capacitance distribution schematic diagram in the present invention in driving transistors.

Fig. 5 is shown as the schematic diagram of active matrix organic light emitting diode display pixel-driving circuit embodiment 1 in the present invention.

Fig. 6 is shown as the schematic diagram of the driver' s timing of active matrix organic light emitting diode display pixel-driving circuit embodiment 1 in the present invention.

Fig. 7 is shown as the schematic diagram of active matrix organic light emitting diode display pixel-driving circuit embodiment 2 in the present invention.

Fig. 8 is shown as the schematic diagram of the driver' s timing of active matrix organic light emitting diode display pixel-driving circuit embodiment 2 in the present invention.

Element numbers explanation

V scan1first scan control signal

V scan2second scan control signal

V sslow supply voltage signal

V emslED control signal

V 1first voltage signal

V 2second voltage signal

T1 the first transistor

T2 transistor seconds

T3 third transistor

T drivedriving transistors

C1 building-out capacitor

1 control gate

2 half floating booms

3 source doping region

4 substrates

5 drain doping region

6 tunneling field-effect transistors

7 diffusion regions

8 diodes

9 heavily doped regions

Embodiment

Below by way of specific instantiation, embodiments of the present invention are described, those skilled in the art the content disclosed by this instructions can understand other advantages of the present invention and effect easily.The present invention can also be implemented or be applied by embodiments different in addition, and the every details in this instructions also can based on different viewpoints and application, carries out various modification or change not deviating under spirit of the present invention.

The unevenness of each pixel drive transistor threshold voltage is compensated in prior art, mostly adopt the mode that multiple electric capacity combines with transistor, although or electric capacity negligible amounts, but number of transistors is more, cause dot structure complicated, reduce the aperture opening ratio of pixel, have impact on video picture quality.Pixel-driving circuit of the present invention can not only compensate the unevenness of each pixel drive transistor threshold voltage effectively, and by have the driving transistors of embedded tunneling field-effect pipe and single electric capacity and a small amount of transistor with the use of, enormously simplify the structure of pixel.

Present invention employs three normal transistor, a driving transistors and a building-out capacitor, wherein, the first transistor and third transistor act synergistically the discharge and recharge path of control and compensation electric capacity first end, the second end that transistor seconds is building-out capacitor provides discharge and recharge path, and avoid Organic Light Emitting Diode other stages outside glow phase luminous, third transistor is by the discharge and recharge path of the first transistor control and compensation electric capacity, and control organic light-emitting diode by driving transistors, driving transistors is for driving organic light-emitting diode, building-out capacitor is for preserving the initial threshold voltage of driving transistors.

It should be noted that, the diagram provided in the embodiment of the present invention only illustrates basic conception of the present invention in a schematic way, then only the assembly relevant with the present invention is shown in graphic but not component count, shape and size when implementing according to reality is drawn, it is actual when implementing, and the kenel of each assembly, quantity and ratio can be a kind of change arbitrarily, and its assembly layout kenel also may be more complicated.

Refer to the schematic diagram of active matrix organic light emitting diode display pixel-driving circuit embodiment 1 in Fig. 5 the present invention.

This active matrix organic light emitting diode display pixel-driving circuit comprises: the first transistor T1, transistor seconds T2, third transistor T3, driving transistors T drive, building-out capacitor C1 and Organic Light Emitting Diode OLED, wherein:

The grid of described the first transistor T1 meets the first scan control signal V scan1, second electrode of the first electrode and third transistor T3 and driving transistors T drivedrain electrode be connected, the second electrode meets first end and the driving transistors T of building-out capacitor C1 drivecontrol gate;

The grid of described transistor seconds T2 is connected to OLED OLED, and the second electrode meets the second voltage signal V 2, first pole of the first electrode and Organic Light Emitting Diode OLED, the second end B of building-out capacitor C1 and driving transistors T drivesource electrode be connected;

The grid sending and receiving optical control signal V of described third transistor T3 ems, the first electrode meets the first voltage signal V 1;

Second pole of described Organic Light Emitting Diode OLED meets low supply voltage signal V ss.Described the first transistor T1 and third transistor T3 acts synergistically the discharge and recharge path of control and compensation electric capacity C1 first end A, the second end B that transistor seconds T2 is building-out capacitor C1 provides discharge and recharge path, and avoid Organic Light Emitting Diode OLED other stages outside glow phase luminous, third transistor T3 by the discharge and recharge path of the first transistor T1 control and compensation electric capacity C1, and passes through driving transistors T drivecontrol Organic Light Emitting Diode OLED luminous, driving transistors T drivefor driving Organic Light Emitting Diode OLED luminous, described building-out capacitor C1 is for preserving driving transistors T driveinitial threshold voltage.

It should be noted that, described the first transistor T1 is symmetrical structure, and its first electrode, the second electrode are interchangeable, in drive circuit works process, can need and current trend according to circuit working, arbitrarily definition its first electrode, the second electrode; Second, third T2/T3 described is symmetrical structure or unsymmetric structure, and generally speaking, in drive circuit works process, its first electrode, the second electrode do not change.

In this embodiment, the annexation of each transistor source and drain electrode can do proper transformation, and such as described first electrode is drain electrode, and the second electrode is source electrode; Or the first electrode is source electrode, the second electrode is drain electrode.When described first electrode is drain electrode, when the second electrode is source electrode, described the first transistor T1, transistor seconds T2 and third transistor T3 are N-type, the first very anode of described Organic Light Emitting Diode OLED; When described first electrode is source electrode, when the second electrode is for drain electrode, described the first transistor T1, transistor seconds T2 and third transistor T3 are P type, the first very negative electrode of described Organic Light Emitting Diode OLED.

In this embodiment, described the first transistor T1, transistor seconds T2 and third transistor T3 are selected from any one in polycrystalline SiTFT, amorphous silicon film transistor, Zinc oxide based film transistor and OTFT.

In this embodiment, described driving transistors T drivecomprise outside control gate 1, source doping region 3, drain doping region 5, also comprise half floating boom 2, and the doping type of described half floating boom 2 and source doping region 3, drain doping region 5 are contrary; Described half floating boom 2 contacts with drain doping region 5 and forms an embedded type diode; Described control gate 1 to extend to above drain doping region 5 and covers its surface, and described half floating boom 2, drain doping region 5 and the control gate 1 extended to above drain doping region 5 form an embedded tunneling field-effect transistor.

It should be noted that, driving transistors T of the present invention drivethe change of self threshold voltage can be realized, by this driving transistors T by its grid of control and drain voltage drivewith single building-out capacitor C1 with the use of, not only compensate for each pixel driving transistors T drivethe unevenness of threshold voltage, and simplify driving circuit.Be that comparison other illustrates driving transistors T of the present invention below with common MOS transistor drivethe principle of adjustment and control of threshold voltage:

The electric conductivity of common MOS transistor raceway groove is by gate voltage regulation and control, and when grid voltage exceedes threshold voltage, the semiconductor surface under grid will transoid (n-type semiconductor become p-type semiconductor or contrary), generates conducting charge.Gate voltage is larger, and the conducting charge quantity of the accumulation in raceway groove is more.

Fig. 3 is the schematic diagram of driving transistors of the present invention.

As shown in Figure 3, described driving transistors T drivecomprise control gate 1, half floating boom 2, source doping region 3, substrate 4, drain doping region 5.As better embodiment, driving transistors T drivestructure is placed in P type substrate 4 or P type trap zone, and its source doping region 3, drain doping region 5 are N-type doping, the polysilicon structure that its half floating boom 2 adulterates for P type.It is to be noted, half floating boom 2 part to be positioned at above raceway groove and to isolate with substrate 4, part contacts with drain doping region 5, and form a more shallow p type diffusion region 7 in the region that half floating boom 2 contacts with drain doping region 5, this p type diffusion region is positioned at drain doping region 5 near substrate 4 surface and region contact with half floating boom 2, and namely the doped region, building 5 that half floating boom 2 of this P type doping and p type diffusion region 7 and N-type are adulterated forms a PN junction diode 8.In addition, control gate 1 covers half floating boom 2 surface by gate oxide and is positioned at the sidewall of drain doping region 2 side, part to extend to above drain doping region 5 and covers its surface, and the N-type heavily doped region 9 that the half floating boom 2/P type diffusion region 7 that this part and P type adulterate and drain doping region 5 draw drain electrode forms an embedded tunneling field-effect transistor 6.It should be noted that, between part half floating boom 2 and substrate 4, between control gate 1 and half floating boom 2 and substrate 4, be all arranged at intervals with gate oxide or other similar insulation systems, this conventional techniques be well known to those skilled in the art, therefore not to repeat here.

Fig. 4 is gate capacitance distribution schematic diagram in the driving transistors of active matrix organic light-emitting diode pixel-driving circuit in the present invention.

As shown in Figure 4, driving transistors T drivecan regard as and insert an electrode (i.e. half floating boom 2) in the gate capacitance medium of normal transistor, so just original gate capacitance has been divided into two electric capacity C g1and C g2series connection.Driving transistors T can be changed by iunjected charge on half floating boom 2 drivethreshold voltage, regulation and control raceway groove electric conductivity.The principle of its regulation and control threshold voltage can be understood as: driving transistors T drivethere is initial threshold voltage V th, as driving transistors T drivewhen starting working, the electric charge that half floating boom 2 injects can by the gate capacitance C between half floating boom 2 and transistor channel g2induce channel charge in transistor channel side, the positive charge on half floating boom 2 is more, and the negative charge responded in raceway groove is also more, and the electric conductivity of N-type raceway groove is stronger.This equivalent is to control gate 1, and compared with before charging with half floating boom 2, control gate 1 need add the channel charge that less gate voltage just can induce equivalent in channels, reach identical conductive effect, so in form driving transistors T drivethreshold voltage just reduce.

This embodiment also provides an active matrix organic light-emitting diode image element driving method, adopts above-mentioned active matrix organic light-emitting diode pixel-driving circuit to realize.Refer to the schematic diagram of the driver' s timing of active matrix organic light emitting diode display pixel-driving circuit embodiment 1 in Fig. 6 the present invention.

It should be noted that, in this embodiment, the first transistor T1, transistor seconds T2 and third transistor T3 are N-type, first electrode of the first transistor T1, transistor seconds T2, third transistor T3 is drain electrode, second electrode is source electrode, the first very anode of Organic Light Emitting Diode OLED, the second very negative electrode.In this embodiment, the negative electrode of Organic Light Emitting Diode OLED connects low supply voltage signal, and preferably, low supply voltage signal is common ground end.

The driving method of described circuit comprises reseting stage, pre-charging stage, threshold voltage memory phase, charge storage stage and glow phase.

It should be noted that, at reseting stage, driving transistors T drivehalf floating boom 2 and drain electrode between PN junction diode 8 positively biased, discharged by third transistor T3; In pre-charging stage, the both end voltage after building-out capacitor C1 charges is higher than driving transistors T driveinitial threshold voltage; In the charge storage stage, charge storage is to driving transistors T drivehalf floating boom 2 in.Driving transistors T drivein embedded tunneling field-effect transistor 6 conducting, the second voltage signal V 2driving transistors T is acted on through transistor seconds T2 drivesource electrode, and through the coupling of building-out capacitor C1 to driving transistors T drivecontrol gate 1, by charge storage to driving transistors T drivehalf floating boom 2 in, to driving transistors T drivehalf floating boom 2 charge, after charging complete, driving transistors T drivethreshold voltage V thbecome Second Threshold voltage V th'.

It should be noted that, in reseting stage, pre-charging stage, threshold voltage memory phase and charge storage stage, the second voltage signal V 2magnitude of voltage be less than second pole tension of Organic Light Emitting Diode OLED and the forward voltage sum of Organic Light Emitting Diode OLED, to make Organic Light Emitting Diode OLED not luminous in reseting stage, pre-charging stage, threshold voltage memory phase and charge storage stage, and only luminous in glow phase.

Below illustrate the driving method in each stage:

Reseting stage: transistor seconds T2 and third transistor T3 conducting, the first transistor T1 turns off, driving transistors T drivedischarged by third transistor T3.

In this stage, the second scan control signal V scan2with LED control signal V emsbe placed in high level, the first scan control signal V scan1be placed in low level, transistor seconds T2 and third transistor T3 conducting, the first transistor T1 turns off, the second voltage signal V 2for data input signal, it is a high value, and voltage range is 0.5V to 5V, but is not enough to make Organic Light Emitting Diode OLED luminous, the first voltage signal V 1be a lower value, voltage range is-1V to-5V.Second voltage signal V 2driving transistors T is arrived by transistor seconds T2 drivesource electrode, and through the coupling of building-out capacitor C1 to driving transistors T drivegrid, now driving transistors T drivegrid voltage be V2, drain voltage is V1, grid voltage higher than drain voltage, driving transistors T drivein half floating boom 2 and drain electrode between PN junction positively biased, driving transistors T drivehalf floating boom 2 discharged by third transistor T3.

Pre-charging stage: the first transistor T1, the equal conducting of transistor seconds T2 and third transistor T3, the first voltage signal V 1by the first transistor T1 and third transistor T3, building-out capacitor C1 is charged.

In this stage, the second scan control signal V scan2with LED control signal V emsbe still high level, the first scan control signal V scan1high level is become, the first transistor T1, the equal conducting of transistor seconds T2 and third transistor T3, the first voltage signal V from low level 1become a high value, and be applied to the first end A of building-out capacitor C1 by third transistor T3 and the first transistor T1, the second voltage signal V 2become a lower value, to make the anode level of Organic Light Emitting Diode OLED not reach the level making Organic Light Emitting Diode OLED luminescence, the second voltage signal V 2the second end B of building-out capacitor C1 is applied to, driving transistors T through transistor seconds T2 drivewhen A, B both end voltage is not also charged to enough large value, be in off state, along with the carrying out of charging, A terminal voltage increases, and A, B both end voltage exceedes driving transistors T drivethreshold voltage, driving transistors T driveconducting, the first end A of building-out capacitor C1 is charged by the first transistor T1 and third transistor T3, and the voltage at final building-out capacitor C1 two ends is higher than driving transistors T driveinitial threshold voltage Vth.

Threshold voltage memory phase: the first transistor T1 and transistor seconds T2 conducting, third transistor T3 turns off, and building-out capacitor C1 is by driving transistors T drivedischarge with transistor seconds T2, when having discharged, the voltage at described building-out capacitor C1 two ends is driving transistors T driveinitial threshold voltage.

In this stage, the first scan control signal V scan1with the second scan control signal V scan2be still high level, LED control signal V emsbecome low level, the first transistor T1 and transistor seconds T2 conducting, third transistor T3 becomes shutoff from unlatching, and V1 no signal inputs, the second voltage signal V 2still remain a lower value, the first end A voltage of building-out capacitor C1 higher than the second end B voltage, driving transistors T drivestill conducting, building-out capacitor C1 is discharged by transistor seconds T2, and the voltage at final building-out capacitor C1 two ends is driving transistors T driveinitial threshold voltage Vth.

The charge storage stage: the first transistor T1 turns off, transistor seconds T2 and third transistor T3 conducting, the second voltage signal V 2driving transistors T is acted on through transistor seconds T2 and building-out capacitor C1 drivecontrol gate 1, and by charge storage to driving transistors T drivehalf floating boom 2 in, driving transistors T drivethreshold voltage vt h become Second Threshold voltage Vth '.

In this stage, the first scan control signal V scan1low level is become, the second scan control signal V from high level scan2with LED control signal V emsbe set to high level, the first transistor T1 becomes shutoff from unlatching, transistor seconds T2 and third transistor T3 conducting, the first voltage signal V 1revert to original high value, the second voltage signal V 2become the data value for showing of actual input, voltage range is that 0V arrives-6V, the second voltage signal V 2driving transistors T is arrived through transistor seconds T2 drivesource electrode, i.e. B point, and through the coupling of building-out capacitor C1 to driving transistors T drivegrid, i.e. A point.Now driving transistors T drivedrain bias, electronics from the valence band tunnelling of p raceway groove to conduction band, driving transistors T drivethe tunneling field-effect transistor of middle embedding is opened, and electric current flows to half floating boom 2, to driving transistors T from drain electrode drivehalf floating boom 2 charge, charge storage is in driving transistors T drivehalf floating boom 2 in, the electric current of tunneling field-effect transistor improves the electromotive force of half floating boom 2, makes driving transistors T drivethreshold voltage vt h reduce, become Vth ', variable quantity is Δ Vth.

Glow phase: the first transistor T1 and transistor seconds T2 turns off, third transistor T3 conducting, driving transistors T drivedrive Organic Light Emitting Diode OLED luminous.

In this stage, the first scan control signal V scan1be still low level, the second sweep trace Vscan2 becomes low level from high level, LED control signal V emsbe still high level, the first transistor T1 and transistor seconds T2 turns off, third transistor T3 conducting, the first voltage signal V 1be still high value, V2 no signal inputs, and the voltage difference at building-out capacitor C1 two ends is driving transistors T driveinitial threshold voltage Vth, and to remain unchanged, driving transistors T drivefor conducting state, drive Organic Light Emitting Diode OLED luminous, driving transistors T drivebe operated in saturation region, the size of drive current is I Tdrive = 1 2 μ W L ( Vth - Vth ′ ) 2 = 1 2 μ W L Δ Vth 2 ,

Wherein, μ is carrier mobility, and W/L is raceway groove length breadth ratio, and Δ Vth is threshold voltage variation amount, I drivefor drive current.

When not considering that raceway groove length breadth ratio W/L and carrier mobility μ affects, drive current I driveonly with driving transistors T drivevth is relevant for threshold voltage variation amount Δ, and Vth is constant for threshold voltage variation amount Δ, therefore driving current constant, and the brightness of Organic Light Emitting Diode OLED remains unchanged within the time of a two field picture.Meanwhile, because drive current is only relevant with threshold voltage variation amount Δ Vth, thus the difference between the different pixels driving transistors initial threshold voltage that causes due to technological factor can be compensated.

It should be noted that, in above-mentioned driving method, in glow phase, first electrode of the first transistor T1 is source electrode, and the second electrode is drain electrode; In other stages, the first electrode of the first transistor is drain electrode, and the second electrode is source electrode.Therefore, the first transistor T1 is symmetrical structure, in the course of the work, its source electrode, drains interchangeable, does not affect driving circuit overall work.

As Alternate embodiments, when the first transistor T1, transistor seconds T2 and third transistor T3 are P-type crystal pipe, driver' s timing correspondingly becomes the level being applicable to the conducting of P-type crystal pipe or shutoff.

Refer to the schematic diagram of the driver' s timing of active matrix organic light emitting diode display pixel-driving circuit embodiment 2 in the schematic diagram of active matrix organic light emitting diode display pixel-driving circuit embodiment 2 in Fig. 7 the present invention and Fig. 8 the present invention.

As different from Example 1, the present embodiment is by the second voltage signal V in embodiment 1 2extremely be connected with second of Organic Light Emitting Diode OLED, in the present embodiment, the second very negative electrode.First voltage signal V 1both as power supply voltage signal, again as data voltage signal.At reseting stage, the first voltage signal V 1be a lower level, voltage range is-1V to-6V, by third transistor T3 to driving transistors T drivehalf floating boom 2 discharge; In pre-charging stage, the first voltage signal V 1magnitude of voltage be supply voltage, by the first transistor T1 and third transistor T3, A point is charged; In the charge storage stage, the first voltage signal V 1level be data voltage V2, the data voltage V2 with display information arrives driving transistors T through third transistor T3 drivedrain terminal, the voltage range of V2 is 1V to 6V.Meanwhile, the negative electrode of Organic Light Emitting Diode OLED becomes low supply voltage signal V ss, voltage range is that 0V arrives-6V, is coupled to the grid of driving tube, final driving transistors T through the effect of electric capacity C1 drivethe tunneling field-effect transistor of middle embedding is opened, to driving transistors T drivehalf floating boom 2 charge; In glow phase, voltage signal line V 1level revert to supply voltage again.

Although compared with embodiment 1, the first voltage signal V in embodiment 2 1with the second voltage signal V 2voltage change to some extent, but the effect that embodiment 2 reached in each driving stage is substantially the same manner as Example 1.The part that embodiment 2 and embodiment 1 repeat please refer to the explanation of embodiment 1, does not repeat them here.

In sum, active matrix organic light emitting diode display pixel-driving circuit of the present invention and driving method thereof, have following beneficial effect:

First, in the present invention in active matrix organic light-emitting diode pixel-driving circuit, adopt the driving transistors with an embedded diode/tunneling field-effect transistor, realize embedded diode/tunneling field-effect transistor by the control gate and drain voltage controlling this driving transistors to be biased, electric current is made to flow to half floating boom from drain electrode, charge storage in half floating boom of driving transistors, thus changes the threshold voltage of driving transistors.Because initial threshold voltage is coupled on driving transistors stored in building-out capacitor by the present invention in advance, during organic light-emitting diode, drive current I driveonly with threshold voltage variation amount Δ V threlevant, and have nothing to do with the initial threshold voltage of driving transistors, thus the impact that the driving transistors initial threshold voltage unevenness avoiding each dot structure in active matrix organic light emitting diode display is brought organic light-emitting diode, the homogeneity of display brightness of image is improved, and active matrix organic light-emitting diode display effect improves.

Secondly, compared with pixel-driving circuit structure each in prior art, in active matrix organic light-emitting diode pixel-driving circuit provided by the invention and driving method, all only adopt the unevenness between each pixel driven transistor threshold voltage of single capacitance compensation, improve the uniformity coefficient of display display, thus improve the display effect of active matrix organic light emitting diode display further.Meanwhile, compared with prior art, in active matrix organic light-emitting diode pixel-driving circuit provided by the invention and driving method, only comprise a capacitance structure, realize driving and signal storage function with driving transistors simultaneously, decrease electric capacity quantity required in driving circuit, further reduce elemental area, greatly simplify dot structure, be conducive to the raising of its aperture opening ratio simultaneously, the dot structure of high integration can be realized.So the present invention effectively overcomes various shortcoming of the prior art and tool high industrial utilization.

Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all without prejudice under spirit of the present invention and category, can modify above-described embodiment or changes.Therefore, such as have in art usually know the knowledgeable do not depart from complete under disclosed spirit and technological thought all equivalence modify or change, must be contained by claim of the present invention.

Claims (11)

1. an active matrix organic light-emitting diode pixel-driving circuit, is characterized in that, described circuit comprises: the first transistor, transistor seconds, third transistor, driving transistors, building-out capacitor and Organic Light Emitting Diode, wherein:
The grid of described the first transistor connects the first scan control signal, and the first electrode is connected with the drain electrode of driving transistors with the second electrode of third transistor, and the second electrode connects the first end of building-out capacitor and the control gate of driving transistors;
The grid of described transistor seconds connects the second scan control signal, and the second electrode connects the second voltage signal, and the first electrode is connected with the source electrode of driving transistors with the first pole of Organic Light Emitting Diode, the second end of building-out capacitor;
The grid sending and receiving optical control signal of described third transistor, the first electrode connects the first voltage signal;
Second pole of described Organic Light Emitting Diode connects low supply voltage signal;
Described driving transistors, except control gate, source electrode, drain electrode, also comprises half floating boom, and the doping type of described half floating boom and source electrode, drain contrary; Described half floating boom contacts with drain doping region and forms an embedded type diode; Described control gate to extend to above drain doping region and covers its surface, and described half floating boom, drain doping region and the control gate extended to above drain doping region form an embedded tunneling field-effect transistor.
2. active matrix organic light-emitting diode pixel-driving circuit according to claim 1, is characterized in that: described second voltage signal is equal with low supply voltage signal.
3. active matrix organic light-emitting diode pixel-driving circuit according to claim 1 and 2, is characterized in that: described the first transistor is symmetrical structure, and its first electrode, the second electrode are interchangeable; Second, third transistor described is symmetrical structure or unsymmetric structure.
4. active matrix organic light-emitting diode pixel-driving circuit according to claim 3, it is characterized in that: described first electrode is drain electrode, second electrode is source electrode, described the first transistor, transistor seconds and third transistor are N-type, the first very anode of described Organic Light Emitting Diode.
5. active matrix organic light-emitting diode pixel-driving circuit according to claim 3, it is characterized in that: described first electrode is source electrode, second electrode is drain electrode, described the first transistor, transistor seconds and third transistor are P type, the first very negative electrode of described Organic Light Emitting Diode.
6. an active matrix organic light emitting diode display image element driving method, adopt the active matrix organic light-emitting diode pixel-driving circuit described in any one in Claims 1 to 5, it is characterized in that, the method comprises:
Reseting stage: transistor seconds and third transistor conducting, the first transistor turns off, and driving transistors is discharged by third transistor;
Pre-charging stage: the equal conducting of the first transistor, transistor seconds and third transistor, the first voltage signal is charged to building-out capacitor by the first transistor and third transistor;
Threshold voltage memory phase: the first transistor and transistor seconds conducting, third transistor turns off, building-out capacitor is by driving transistors and transistor seconds electric discharge, and when having discharged, the voltage at described building-out capacitor two ends is the initial threshold voltage of driving transistors;
The charge storage stage: the first transistor turns off, transistor seconds and third transistor conducting, second voltage signal acts on the control gate of driving transistors through transistor seconds and building-out capacitor, and by charge storage in half floating boom of driving transistors, the threshold voltage of driving transistors becomes Second Threshold voltage;
Glow phase: the first transistor and transistor seconds turn off, third transistor conducting, and driving transistors drives organic light-emitting diode.
7. active matrix organic light emitting diode display image element driving method according to claim 6, it is characterized in that: at reseting stage, diode positively biased between half floating boom of driving transistors and drain electrode, is discharged by half floating boom of third transistor to driving transistors.
8. active matrix organic light emitting diode display image element driving method according to claim 6, is characterized in that: in pre-charging stage, and the both end voltage after building-out capacitor charging is higher than the initial threshold voltage of driving transistors.
9. active matrix organic light emitting diode display image element driving method according to claim 6, it is characterized in that: in the charge storage stage, embedded tunneling field-effect transistor conducting in driving transistors, second voltage signal acts on the source electrode of driving transistors through transistor seconds, and through the coupling of building-out capacitor to the control gate of driving transistors, by charge storage in half floating boom of driving transistors, half floating boom of driving transistors is charged, after charging complete, the threshold voltage of driving transistors becomes Second Threshold voltage.
10. active matrix organic light emitting diode display image element driving method according to claim 6, it is characterized in that: in glow phase, the voltage difference at building-out capacitor two ends is the initial threshold voltage of driving transistors and remains unchanged, and the luminosity of Organic Light Emitting Diode remains unchanged within the time of a two field picture.
11. active matrix organic light emitting diode display image element driving methods according to claim 6, it is characterized in that: in reseting stage, pre-charging stage, threshold voltage memory phase and charge storage stage, the magnitude of voltage of the second voltage signal is less than the second pole tension of Organic Light Emitting Diode and the forward voltage sum of Organic Light Emitting Diode.
CN201310629215.5A 2013-11-29 2013-11-29 Active matrix organic light-emitting diode pixel-driving circuit and driving method thereof CN103606351B (en)

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CN105788511A (en) * 2014-12-22 2016-07-20 昆山国显光电有限公司 Pixel driving circuit and display device
JP2018528455A (en) * 2015-07-21 2018-09-27 シェンジェン ロイオル テクノロジーズ カンパニー リミテッドShenzhen Royole Technologies Co., Ltd. Pixel circuit, driving method thereof, and display panel
CN105976754A (en) * 2016-03-19 2016-09-28 上海大学 Silicon-based organic light-emitting micro-display pixel driving circuit
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