CN102568373B - Organic light-emitting diode (LED) pixel circuit and display device - Google Patents
Organic light-emitting diode (LED) pixel circuit and display device Download PDFInfo
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- CN102568373B CN102568373B CN201010615798.2A CN201010615798A CN102568373B CN 102568373 B CN102568373 B CN 102568373B CN 201010615798 A CN201010615798 A CN 201010615798A CN 102568373 B CN102568373 B CN 102568373B
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Abstract
The invention provides an organic light-emitting diode (LED) pixel circuit and a display device. The organic LED pixel circuit comprises an organic LED, a drive transistor and a resistor, wherein the organic LED is driven to emit light by the source drain current of the drive transistor; the resistor is coupled to a source electrode of the drive transistor, and is used for restraining the change of the source drain current through changing the voltage of the drive transistor when the strength of the source drain current is changed. According to the organic LED pixel circuit and the display device, the resistor is additionally arranged on the source electrode of the drive transistor in the organic LED pixel circuit, so that the voltage of the drive transistor can be changed along with the drift of the current Id, and is fed back to the drive transistor, thereby, the variation of the current Id is reduced, and the condition that a display effect is changed because of current drift is improved.
Description
Technical field
The present invention relates to active organic light-emitting diode (AMOLED, Active Matrix OrganicEmitting Diode) field, particularly a kind of organic light-emitting diode pixel circuit and display device.
Background technology
Along with updating of active organic light-emitting diode (AMOLED) technology, the advantages such as its visual angle is wide, color contrast is effective, fast response time and low cost are obvious all the more, receive the concern of increasing flat-panel monitor (Flat Panel Display) manufacturer in display field.Therefore, displayer becomes the focal point of current display industry.
AMOLED can be equivalent to diode, by controlling the electric current of Organic Light Emitting Diode (OLED, OrganicEmitting Diode), can control brightness to show GTG.Due to the driving feature of OLED, most OLED pixel circuit is 2T1C structure.
Fig. 1 is the circuit diagram of a kind of conventional organic light-emitting diode pixel (2T1C structure).As shown in Figure 1, this circuit comprises transistor Ma, Mb and electric capacity C.Wherein, the grid of transistor Ma is connected to sweep signal Select [n], and source electrode is connected to data-signal Data [m], and drain electrode is connected to node A; The grid of transistor Mb is connected to node A, and source electrode is connected to pixel power VDD, and drain electrode is connected to OLED anode.Basic functional principle is: the switching characteristic utilizing Ma, using data line signal voltage transmission to A point as the grid voltage of Mb.By control A point voltage, namely can be operated in saturation region by control Mb, and the voltage difference of Mb grid source can determine the electric current flowing through Mb.
Generally speaking, the display brightness of Organic Light Emitting Diode is directly proportional to the electric current I d flowing through Organic Light Emitting Diode.When Organic Light Emitting Diode is operated in saturation region, the expression formula of electric current I d is: Id=1/2*u*Cox* (W/L) * (Vgs-Vth)
2.Wherein, u is carrier mobility, and Cox is gate oxide capacitance, and W/L is transistor breadth length ratio, and Vgs is source grid voltage, and Vth is threshold voltage.As shown from the above formula, when other values remain unchanged, change Vgs, namely can change Id.
But, the defect of organic light-emitting diode pixel (2T1C structure) circuit of prior art is: in actual applications, due to the impact of the conditions such as manufacture craft, inevitably there is certain drift in carrier mobility u and threshold voltage vt h, pixel power voltage VDD because to flow through electric current also have on circuit voltage drop impact; These all can change the value of Id, make Id produce drift, thus the display effect of OLED is deteriorated.
Summary of the invention
Technical matters to be solved by this invention is, in organic light-emitting diode pixel circuit of the prior art, current drift makes display effect be deteriorated.
For achieving the above object, the invention provides a kind of organic light-emitting diode pixel circuit, described organic light-emitting diode pixel circuit comprises: Organic Light Emitting Diode and driving transistors, and the source-drain current of described driving transistors drives described organic light-emitting diode; Resistor, is coupled to the source electrode of described driving transistors, in order to when described source-drain current size changes, is suppressed the change of described source-drain current by the voltage changing described driving transistors.
Preferably, described driving transistors is P-type crystal pipe, and its source electrode is connected with pixel power by described resistor, and its drain electrode is connected to the anode of described light emitting diode, and the negative electrode of described light emitting diode is connected to fixing electronegative potential.
Preferably, described driving transistors is N-type transistor, and its source electrode is connected with fixing electronegative potential by described resistor, and its drain electrode is connected to the negative electrode of described light emitting diode, and the anode of described light emitting diode is connected to pixel power.
Preferably, described organic light-emitting diode pixel circuit also comprises sweep trace, data line and on-off element, and described on-off element is connected between the grid of described data line and described driving transistors, and determines its on off state according to the control signal of sweep trace.
Preferably, described on-off element is P-type crystal pipe or N-type transistor.
Preferably, described organic light-emitting diode pixel circuit also comprises the capacitor between grid and any set potential being connected to described driving transistors.
Preferably, the span of described resistor is 100K-1M.
Present invention also offers a kind of display device, described display device comprises the organic light-emitting diode pixel circuit as described in any one of claim 1-7.
Beneficial effect of the present invention is, resistor is increased by the source electrode of the driving transistors in organic light-emitting diode pixel circuit, the voltage of driving transistors can be changed along with the drift of electric current I d, and feed back to driving transistors, thus reduce the knots modification of Id, improve the change of the display effect that current drift causes.
Accompanying drawing explanation
Accompanying drawing described herein is used to provide a further understanding of the present invention, forms a application's part, does not form limitation of the invention.In the accompanying drawings:
Fig. 1 is the structural representation of organic light-emitting diode pixel circuit traditional in prior art;
Fig. 2 is the structural representation of the organic light-emitting diode pixel circuit that the embodiment of the present invention one provides;
The structural representation of Fig. 3 to be Fig. 2 breaker in middle element be organic light-emitting diode pixel circuit of N-type transistor;
Fig. 4 is the schematic diagram of B point voltage change on the impact of Id in Fig. 2;
Fig. 5 is that in the image element circuit structure that provides of the embodiment of the present invention one and traditional structure, Vth drifts about and affects comparison diagram to Id;
Fig. 6 is that in the image element circuit structure that provides of the embodiment of the present invention one and traditional structure, u drifts about and affects comparison diagram to Id;
Fig. 7 is that in the image element circuit structure that provides of the embodiment of the present invention one and traditional structure, VDD drifts about and affects comparison diagram to Id;
Fig. 8 is the structural representation of the organic light-emitting diode pixel circuit that the embodiment of the present invention two provides;
The structural representation of Fig. 9 to be Fig. 8 breaker in middle element be organic light-emitting diode pixel circuit of P-type crystal pipe.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with accompanying drawing, the embodiment of the present invention is described in further detail.At this, schematic description and description of the present invention is for explaining the present invention, but not as a limitation of the invention.
Embodiment one:
The structural representation of the organic light-emitting diode pixel circuit that Fig. 2 provides for the embodiment of the present invention one.As shown in Figure 2, sweep trace Select [n] and data line Data [m] defines the pixel region of this organic light-emitting diode pixel.On-off element 201 is connected between data line Data [m] and the grid of driving transistors 202, and on-off element 201 determines its on off state according to the control signal of sweep trace Select [n].When on-off element 201 conducting, the data-signal on data line Data [m] is transferred to the grid of driving transistors 202, controls the switch of driving transistors 202.Driving transistors 202 is P-type crystal pipe, the general TFT adopting P type.The source electrode of driving transistors 202 is connected with pixel power VDD by a resistor R 204, and its drain electrode is connected to the anode of Organic Light Emitting Diode OLED 205; The negative electrode of Organic Light Emitting Diode OLED 205 is connected to fixing electronegative potential (being ground connection in figure).Capacitor C 203 is connected between the grid of driving transistors 202 and pixel power VDD.
Fig. 2 is only a preferred embodiment of the present invention, and in fact, capacitor C 203 can be connected between the grid of driving transistors 202 and any set potential.This set potential can be pixel power VDD (as shown in Figure 2), also can be ground connection, can also be other any set potentials.
As one preferred embodiment, on-off element 201 can be N-type transistor (as N-TFT) as shown in Figure 3, also can be P-type crystal pipe (as P-TFT).
As one preferred embodiment, the span of resistor R 204 is 100K-1M.
Image element circuit shown in composition graphs 2 or 3, is further described its principle of work and effect.
In the present embodiment, the expression formula flowing through the electric current of Organic Light Emitting Diode 205 can be expressed as follows again:
Id＝1/2*u*Cox*(W/L)*(Vgs-Vth)
2＝1/2*u*Cox*(W/L)*(Vg-Vs-Vth)
2
Wherein, Vg is the grid voltage of driving transistors 202, and Vs is the source voltage of driving transistors 202.As above formula is known, when Vth decline causes Id to rise time, if reduce Vs, (Vg-Vs-Vth) just can be made to remain unchanged, thus eliminate the impact of Vth reduction on Id.
In like manner, if Vth raises, then strengthen Vs, also can reach the impact of Vth change on Id.For mobility u, obtain from above formula equally, if u becomes large, then reduce Vs; If u diminishes, then increase Vs.Like this, just can be controlled by the change of Vs, Id is compensated, reach the object improving display effect.
As shown in figures 2 and 3, resistor R 204 is the large resistance increased, and it can realize the dynamic adjustment function of B point voltage.When the Id of the driving transistors 202 being operated in saturation region drifts about, will have influence on the electric current flowing through resistor R 204, the voltage (i.e. Vs) of such B point just changes.Suppose that VDD immobilizes, from aforementioned discussion, the change of Vs can cause the change of (Vg-Vs-Vth) then to feed back to Id, in time reaching equilibrium point, the Id skew that will cause being drifted about by Vth or u compensates, to reduce the impact of drift on device performance.
Fig. 4 is the impact of B point voltage change on Id.Discussion prerequisite is above that VDD remains unchanged, and when VDD changes, the above results is still set up.Suppose that VDD declines, then Id reduces, and causes B point voltage (Vs) to raise, feeds back to driving transistors 202, make Id increase, and reaches the object reducing Id knots modification.The situation that VDD rises also is like this.
The organic LED pixel structure that Fig. 5 provides for embodiment one and traditional structure Vth drift about and affect comparison diagram to Id, horizontal ordinate is that (unit is v), the electric current knots modification number percent of ordinate when to be Id get-1.5v relative to Vth for the Vth of driving transistors 202.Curve 1 is the measurement result of traditional structure; The measurement result of the organic LED pixel structure that curve 2 provides for embodiment one.
The organic LED pixel structure that Fig. 6 provides for embodiment one and traditional structure u drift about and affect comparison diagram to Id, and horizontal ordinate is that (unit is cm for the u of driving transistors 202
2/ (s*v)), ordinate is that Id gets 80cm relative to u
2electric current knots modification number percent during/(s*v).Curve 1 is the measurement result of traditional structure; The measurement result of the organic LED pixel structure that curve 2 provides for embodiment one.
Fig. 7 is that the organic LED pixel structure that provides of embodiment one and traditional structure VDD change and affect comparison diagram to Id, and horizontal ordinate is delta VDD, and ordinate is Id knots modification number percent.Curve 1 is the measurement result of traditional structure; The measurement result of the organic LED pixel structure that curve 2 provides for embodiment one.
From Fig. 5, Fig. 6 and Fig. 7, after the organic LED pixel structure adopting embodiment one to provide, the impact of drift on Id of Vth, u and VDD can be effectively reduced.
The structural representation of the organic light-emitting diode pixel circuit that Fig. 8 provides for the embodiment of the present invention two.As shown in Figure 8, sweep trace Select [n] and data line Data [m] defines the pixel region of this organic light-emitting diode pixel.On-off element 801 is connected between data line Data [m] and the grid of driving transistors 802, and on-off element 801 determines its on off state according to the control signal of sweep trace Select [n].When on-off element 801 conducting, the data-signal on data line Data [m] is transferred to the grid of driving transistors 802, controls the switch of driving transistors 802.Driving transistors 802 is N-type transistor, the general TFT adopting N-type.The source electrode of driving transistors 802 is connected with fixing electronegative potential (being ground connection in figure) by a resistor R 804, and its drain electrode is connected to the negative electrode of Organic Light Emitting Diode OLED 805; The anode of Organic Light Emitting Diode OLED805 is connected to pixel power VDD.Capacitor C 803 is connected between the grid of driving transistors 802 and pixel power VDD.
Fig. 8 is only a preferred embodiment of the present invention, and in fact, capacitor C 803 can be connected between the grid of driving transistors 802 and any set potential.This set potential can be pixel power VDD (as shown in Figure 2), also can be ground connection, can also be other any set potentials.
As one preferred embodiment, on-off element can be P-type crystal pipe (as P-TFT) as shown in Figure 9, also can be N-type transistor (as N-TFT).
As one preferred embodiment, the span of resistor R 804 is 100K-1M.
The principle of work of the organic light-emitting diode pixel circuit that the principle of work of the organic light-emitting diode pixel circuit that embodiment two provides and embodiment one provide is similar, is not repeated at this.
The present invention also provides a kind of display device, and this display device comprises the organic light-emitting diode pixel circuit that enforcement one or embodiment two as mentioned above provide.
From above-described embodiment, by adding resistor, make in organic light-emitting diode pixel circuit, the voltage of transistor can change along with the drift of Id, and feed back to transistor, thus namely the knots modification reducing Id suppresses the change of Id, improves the change of the display effect that current drift causes.
Those of ordinary skill in the art can also recognize further, in conjunction with unit and the algorithm steps of each example of embodiment disclosed herein description, can realize with electronic hardware, computer software or the combination of the two, in order to the interchangeability of hardware and software is clearly described, generally describe composition and the step of each example in the above description according to function.These functions perform with hardware or software mode actually, depend on application-specific and the design constraint of technical scheme.Professional and technical personnel can use distinct methods to realize described function to each specifically should being used for, but this realization should not thought and exceeds scope of the present invention.
The software module that the method described in conjunction with embodiment disclosed herein or the step of algorithm can use hardware, processor to perform, or the combination of the two is implemented.Software module can be placed in the storage medium of other form any known in random access memory (RAM), internal memory, ROM (read-only memory) (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field.
Above-described embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only the specific embodiment of the present invention; the protection domain be not intended to limit the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (7)
1. an organic light-emitting diode pixel circuit, is characterized in that, described organic light-emitting diode pixel circuit comprises:
Organic Light Emitting Diode and driving transistors, the source-drain current of described driving transistors drives described organic light-emitting diode;
Resistor, is coupled to the source electrode of described driving transistors, in order to when described source-drain current size changes, is suppressed the change of described source-drain current by the voltage changing described driving transistors;
Electric capacity, is connected between the grid of described driving transistors and any set potential.
2. organic light-emitting diode pixel circuit according to claim 1, it is characterized in that, described driving transistors is P-type crystal pipe, its source electrode is connected with pixel power by described resistor, its drain electrode is connected to the anode of described light emitting diode, and the negative electrode of described light emitting diode is connected to fixing electronegative potential.
3. organic light-emitting diode pixel circuit according to claim 1, it is characterized in that, described driving transistors is N-type transistor, its source electrode is connected with fixing electronegative potential by described resistor, its drain electrode is connected to the negative electrode of described light emitting diode, and the anode of described light emitting diode is connected to pixel power.
4. the organic light-emitting diode pixel circuit according to any one of claim 1-3, it is characterized in that, described organic light-emitting diode pixel circuit also comprises sweep trace, data line and on-off element, described on-off element is connected between the grid of described data line and described driving transistors, and determines its on off state according to the control signal of sweep trace.
5. organic light-emitting diode pixel circuit according to claim 4, is characterized in that, described on-off element is P-type crystal pipe or N-type transistor.
6. the organic light-emitting diode pixel circuit according to any one of claim 1-3, is characterized in that, the span of described resistor is 100K-1M.
7. a display device, is characterized in that, described display device comprises the organic light-emitting diode pixel circuit as described in any one of claim 1-6.
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| CN201010615798.2A CN102568373B (en) | 2010-12-27 | 2010-12-27 | Organic light-emitting diode (LED) pixel circuit and display device |
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| CN102568373B true CN102568373B (en) | 2015-05-13 |
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| CN102890910B (en) * | 2012-10-15 | 2015-06-10 | 京东方科技集团股份有限公司 | Synchronous and asynchronous bi-gate thin film transistor (TFT)-organic light emitting diode (OLED) pixel drive circuit and drive method thereof |
| US9105238B2 (en) * | 2013-04-25 | 2015-08-11 | International Business Machines Corporation | Active matrix triode switch driver circuit |
| CN104599631B (en) * | 2014-12-16 | 2017-07-11 | 昆山工研院新型平板显示技术中心有限公司 | Image element circuit and its driving method and active matrix/organic light emitting display |
| CN111341273B (en) * | 2018-12-29 | 2021-09-17 | Tcl科技集团股份有限公司 | Backlight control method applied to display device |
| CN109859693B (en) * | 2019-02-26 | 2020-12-08 | 上海天马有机发光显示技术有限公司 | Array substrate and display device |
| WO2020181512A1 (en) * | 2019-03-13 | 2020-09-17 | 京东方科技集团股份有限公司 | Pixel circuit and driving method therefor, and display apparatus |
| CN111179838A (en) | 2020-02-21 | 2020-05-19 | 深圳市华星光电半导体显示技术有限公司 | Pixel circuit, display panel and method for improving low gray scale uniformity of display panel |
| CN111833815B (en) * | 2020-07-31 | 2022-05-31 | 合肥京东方卓印科技有限公司 | Pixel driving circuit and method, display panel and driving method |
| CN112652270B (en) * | 2020-12-28 | 2021-11-23 | 武汉天马微电子有限公司 | Pixel circuit, display panel and display device |
| CN112908248A (en) * | 2021-03-02 | 2021-06-04 | 深圳市华星光电半导体显示技术有限公司 | Pixel driving circuit and display panel |
| CN113421521B (en) * | 2021-06-15 | 2023-05-05 | Tcl华星光电技术有限公司 | Backlight driving circuit, driving method and backlight module |
| CN113674702A (en) * | 2021-08-02 | 2021-11-19 | Tcl华星光电技术有限公司 | Pixel driving circuit and mobile terminal |
| CN113674701A (en) * | 2021-08-02 | 2021-11-19 | Tcl华星光电技术有限公司 | Pixel driving circuit and mobile terminal |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1319039C (en) * | 2003-03-21 | 2007-05-30 | 友达光电股份有限公司 | Active matrix organic light emitting diode pixel circuit capable of automatically compensating current |
| TW200802274A (en) * | 2006-06-29 | 2008-01-01 | Au Optronics Corp | Organic light emitting diode (OLED) pixel circuit and brightness control method thereof |
| CN101828213A (en) * | 2007-10-19 | 2010-09-08 | 全球Oled科技有限责任公司 | Display device and pixel circuit |
| CN101859543A (en) * | 2010-05-26 | 2010-10-13 | 四川虹视显示技术有限公司 | Method for improving brightness uniformity of AMOLED panel |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI284875B (en) * | 2004-06-21 | 2007-08-01 | Au Optronics Corp | Method for improving uniformity of current-driving display and current-driving display fabricated thereby |
-
2010
- 2010-12-27 CN CN201010615798.2A patent/CN102568373B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1319039C (en) * | 2003-03-21 | 2007-05-30 | 友达光电股份有限公司 | Active matrix organic light emitting diode pixel circuit capable of automatically compensating current |
| TW200802274A (en) * | 2006-06-29 | 2008-01-01 | Au Optronics Corp | Organic light emitting diode (OLED) pixel circuit and brightness control method thereof |
| CN101828213A (en) * | 2007-10-19 | 2010-09-08 | 全球Oled科技有限责任公司 | Display device and pixel circuit |
| CN101859543A (en) * | 2010-05-26 | 2010-10-13 | 四川虹视显示技术有限公司 | Method for improving brightness uniformity of AMOLED panel |
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