CN104078007A - Active light-emitting display device pixel circuit - Google Patents
Active light-emitting display device pixel circuit Download PDFInfo
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- CN104078007A CN104078007A CN201410308175.9A CN201410308175A CN104078007A CN 104078007 A CN104078007 A CN 104078007A CN 201410308175 A CN201410308175 A CN 201410308175A CN 104078007 A CN104078007 A CN 104078007A
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Abstract
An active light-emitting display device is a device driven by the current, so that voltage drop occurs between cathode voltage and anode voltage along with cabling, and causes changes in Vgs of a driving transistor of the active light-emitting display device so as to cause changes in the current of the active light-emitting display device, and thus display uniformity difference is generated. The current method for solving the problem of display uniformity is to increase the voltage difference between the cathode and the anode and reduce the ratio of the voltage drop in the Vgs so as to improve uniformity; however, the current scheme will result in large power consumption, and the color reducibility is affected by current loading. According to the active light-emitting display device, a solution is provided, both the uniformity and the color reducibility are not affected by the voltage drop. Meanwhile, the problem of uniformity caused by the voltage drop needs not to be considered in the circuit, so that the voltage value between the cathode and the anode can be greatly reduced, and power consumption can be greatly reduced.
Description
Technical field
The invention provides a kind of active illuminating display device image element circuit.
Background technology
Active illuminating device, if AMOLED display technique is because of its high chroma territory, high response speed, the feature such as more frivolous, is just replacing LCD technology at present and is becoming gradually the strong rival in display technique of future generation field.The AMOLED display technique of current employing LTPS device drive is volume production.At present a lot of research institutions also study and in monocrystalline substrate, do the AMOLED of monocrystalline silicon metal-oxide-semiconductor driving or the technology of AMLED device.In addition, also there are a lot of research institutions at research amorphous silicon and oxide semiconductor, to drive the volume production feasibility of AMOLED.
Due to the resistance that metal routing certainly exists, therefore, the electric current that active illuminating device needs can produce voltage drop while transmitting on metal wire.Cause negative electrode and anode voltage in viewing area, to produce inhomogeneity.The voltage drop in the region of transmission line length is larger.The Vgs voltage of the voltage influence driving tube of negative electrode anode, causes the inhomogeneity of drive current and then causes the inhomogeneity of display brightness.On the other hand, a same Show Color, because the difference of whole displaying contents is different, therefore, color reducibility is poor.
The way of improving at present inhomogeneity is to increase the voltage of cathode/anode, increase Vgs, thereby the ratio of reduction voltage drop in Vgs, and then control brightness homogeneity.In addition on the one hand, reduce the breadth length ratio of driving transistors, with balance, increase the increase of Vgs voltage band incoming current.This way can be improved brightness disproportionation one property, still, can significantly increase power consumption.Also cannot change the poor problem of color reducibility.
Summary of the invention
The invention provides a kind of active illuminating display device image element circuit, show the solution that homogeneity and color reducibility are not affected by voltage drop.Meanwhile, because the problem of the homogeneity that circuit does not need to consider that voltage drop causes can reduce the magnitude of voltage between negative electrode and positive electrode greatly, power consumption can greatly be reduced.
The method principle of work is as follows: the image element circuit of AMOLED of PMOS pipe of take is example.If magnitude of voltage when power anode voltage is not decayed through cabling is Vdd0, is Vddi, i.e. Vdd0 – I (display content) * R (x, y)=Vddi after walking line attenuation.Wherein, I is with whole displaying contents, and R is the value with viewing area change.Vdata-Vdd0 is the target control voltage of PMOS driving tube.
Existing pixel-driving circuit scheme as shown in Figure 1, when signal arrives, state writes transistor T 1 and opens, data-signal Vdata writes memory capacitance Cs, state writes transistor T 1 close after, show state is latched in memory capacitance Cs, and now, the voltage latching and anode voltage source Vddi are respectively grid voltage and the source voltage of driving transistors.Driving tube T2 gate source voltage has determined the electric current by OLED.Poor Vgs=the Vdata of gate source voltage – Vddi=Vdata – Vdd0+I (display content) * R (x in circuit now, y). this voltage is subject to the impact of whole displaying contents and viewing area, has caused showing inhomogeneity and the poor problem of color reducibility.
Solution pixel-driving circuit scheme of the present invention as shown in Figure 2, increases an independent current source Vdd0 in image element circuit, and Vdd0 does not provide drive current to display pixel, therefore there is no voltage drop, and in viewing area, magnitude of voltage is identical.Memory capacitance Cs connect one end of set potential Vddi originally, change into while being connected respectively to Vdd0 and the renewal of Vddi. memory capacitance state by two transistor Ts 2 and T3 switch, T2 opens, T3 closes, the voltage difference of electric capacity is Vdata-Vdd0, during memory capacitance state hold mode, T3 opens, and T2 closes.The voltage difference of memory capacitance is still Vdata-Vdd0, because one end connects set potential by transistor T 3, is Vddi, and therefore, the voltage of memory capacitance is Vdata-Vdd0+Vddi.The gate source voltage of driving transistors is that the voltage of memory capacitance deducts anode voltage Vgs=(Vdata-Vdd0+Vddi)-Vddi=Vdata-Vdd0; Therefore, grid source driving voltage Vgs=Vdata – Vdd0 that driving way of the present invention can make driving transistors T4 be fixed, therefore, the demonstration of each pixel of driving that can be independently stable.Greatly improved the reductibility that shows homogeneity and display color.
It is more than schematic illustration, the present invention is applicable to the active illuminating image element circuit of various compensation and optimizational function, frame construction drawing as shown in Figure 4, after when gate signal arrives, T1 opens, data-signal Vata writes memory capacitance CS, the size of the poor control display device of the source voltage electric current of CS and driving transistors through over-compensation and after optimizing.Affected by voltage drop.There is the poor and poor problem of color reducibility of homogeneity.
Fig. 5 is compensation after the present invention applies and the active illuminating image element circuit schematic diagram of optimizational function.If after Vdata compensating circuit be Vdata '.In image element circuit, increase an independent current source Vdd0, Vdd0 does not provide drive current to display pixel, therefore there is no voltage drop, and in viewing area, magnitude of voltage is identical.Memory capacitance Cs connect one end of set potential Vddi originally, change into while being connected respectively to Vdd0 and the renewal of Vddi. memory capacitance state by two transistor Ts 2 and T3 switch, T2 opens, T3 closes, the voltage difference of electric capacity is Vdata '-Vdd0, during memory capacitance state hold mode, T3 opens, and T2 closes.The voltage difference of memory capacitance is still Vdata '-Vdd0, because one end connects set potential by transistor T 3, is Vddi, and therefore, the voltage of memory capacitance is Vdata '-Vdd0+Vddi.The gate source voltage of driving transistors is that the voltage of memory capacitance deducts anode voltage Vgs=(Vdata '-Vdd0+Vddi)-Vddi=Vdata '-Vdd0; Therefore, grid source driving voltage Vgs=Vdata ’ – Vdd0 that driving way of the present invention can make driving transistors T4 be fixed, therefore, the demonstration of each pixel of driving that can be independently stable.Greatly improved the reductibility that shows homogeneity and display color.
The present invention is applicable to the Dual Drive pipe AC driving circuit of Fig. 6.Principle is all identical, does not repeat them here.
Other current drives active illuminating display device, preserves the various circuit of signal condition by memory capacitance.All can adopt the solution of the present invention, principle is identical, at this, also repeats no more.
Accompanying drawing explanation:
Accompanying drawing 1 is conventional P MOS AMOLED 2T1C image element circuit key diagram.
Accompanying drawing 2 improves rear image element circuit key diagram for conventional P MOS AMOLED 2T1C adopts the present invention.
Accompanying drawing 3 is the embodiment of conventional P MOS AMOLED 2T1C, increases the circuit diagram with light emitting control function.
Accompanying drawing 4 is the circuit diagram of the compensation of tradition band and optimized circuit.
For the present invention is applied to, tradition band compensates accompanying drawing 5 and the embodiment of optimized circuit.
Accompanying drawing 6 is the circuit diagram of two-tube driven mode circuit.
Accompanying drawing 7 is applied to the embodiment of two-tube driven mode circuit for the present invention.
Accompanying drawing 8 is the image element circuit figure of current LTPS AMOLED threshold voltage compensating circuit.
Accompanying drawing 9 is applied to the embodiment of current LTPS AMOLED threshold voltage compensating circuit for the present invention.
Embodiment
What introduce below is the some in a plurality of embodiment of the present invention, aims to provide basic understanding of the present invention, is not intended to confirm key of the present invention or decisive key element or limits claimed scope.According to technical scheme of the present invention, do not changing under connotation of the present invention, can mutually replace and obtain other implementation.If source-drain electrode is just as the differentiation of electrode, be physically symmetrical structure, interchangeable.For another the electric capacity existing between leakage the two poles of the earth, amorphous silicon film transistor source and grid, on this circuit base, between any transistorized grid source or the circuit that adds arbitrary size electric capacity between grid leak include in this circuit scope of invention.For another example, after the connection in series-parallel of electric capacity, be still electric capacity, transistorized string and after be still transistor circuit characteristic etc., if any circuit equivalent electrical circuit is identical with circuit of the present invention, still within the invention scope of this circuit.
One embodiment of the invention, please refer to Fig. 3, EM signal at stop T5 first, thus close OLED device operation current, guarantee display effect when OLED duty when show state replaces can not affect normal work.Then Gate unblanking, Data signal and Vdd0 are written to the two ends of CS, after making the voltage of CS remain Vdata-Vdd0, Gate closes, then EM signal is opened T5 and T3, when making the normal work of OLED device, make the storage voltage of CS remain Vddi+Vdata-Vdd0, the gate source voltage of driving tube T4 is Vddi+Vdata-Vdd0-Vddi=Vdata-Vdd0.For irrelevant with voltage drop, therefore, the working current of T4 and voltage drop are irrelevant.The face that obtains distributes and shows preferably homogeneity and color reducibility.
As shown in Figure 4, the annealing inhomogeneity of the current ELA technique due to LTPS can cause the uneven problem of ELA, yield is lower, therefore major part has just all adopted compensating circuit as shown in Figure 4 at the product of volume production at present, according to the characteristic of driving tube T4, after being compensated, the data signal writing deposits CS in.Another embodiment of the present invention, as shown in Figure 5, the one end of originally receiving Vddi at CS changes into by two switching transistors and is connected to Vdd0 and Vddi, and principle of work is identical, and with reference to explanation, this does not repeat.
As shown in Figure 6, because amorphous silicon or IGZO device exist the problem of threshold voltage drift, after long-time driving tube forward grid voltage loads, can there is the phenomenon of the threshold voltage drift in characteristic in TFT device.Can adopt the mode of two-tube (T4 and T5) driven, eliminate the phenomenon of threshold voltage drift.Another embodiment of the present invention, the one end of originally receiving Vddi at two CS changes into by two switching transistors and is connected to Vdd0 and Vddi, and principle of work is identical, and with reference to the part of explanation, this does not repeat.
As shown in Figure 8, the image element circuit of current main-stream AMOLED-LTPS product is the circuit of the threshold voltage of compensation driving tube T5.As shown in Figure 9, the one end of originally receiving Vddi at two CS changes into by two switching transistors and is connected to Vdd0 and Vddi embodiments of the invention, and principle of work is identical, and with reference to the part of explanation, this does not repeat.
Claims (12)
1. an active active illuminating display device image element circuit, comprises that state writes transistor, state memory capacitance, driving transistors, luminescent device, described image element circuit, it is characterized in that, one end of state memory capacitance is connected with two voltage signals respectively by two transistors.
2. image element circuit claimed in claim 1, is characterized in that, one end of state memory capacitance is connected with two voltage signals respectively by two transistors, and one of them is for providing the anode voltage source of electric current to luminescent device.
3. image element circuit claimed in claim 2, it is characterized in that, in the time keeping at memory capacitance state, the anode voltage source that provides electric current to luminous that is communicated to is opened by one of them transistor in one end of memory capacitance, and in the time of upgrading at memory capacitance state, by another transistor, open and be communicated to another voltage signal.
4. image element circuit claimed in claim 3, is characterized in that, another described voltage signal, and the value of its voltage when giving the luminous anode voltage source that electric current is provided through cabling evanescent voltage equates.
5. image element circuit claimed in claim 1, is characterized in that, one end of state memory capacitance is connected with two voltage signals respectively by two transistors, and one of them is for giving the luminous cathodic electricity potential source that electric current is provided.
6. image element circuit claimed in claim 5, it is characterized in that, in the time keeping at memory capacitance state, one end of memory capacitance is opened and is communicated to the cathodic electricity potential source that provides electric current to luminous by one of them transistor, and in the time of upgrading at memory capacitance state, by another transistor, open and be communicated to another voltage signal.
7. image element circuit claimed in claim 6, is characterized in that, another described voltage signal, and its voltage is for equating to the value of the luminous cathodic electricity potential source that electric current is provided when crossing cabling evanescent voltage.
8. image element circuit claimed in claim 1, is characterized in that, one end of state memory capacitance is connected with two voltage signals respectively by two transistors, one of them be around the luminous anode of same color.
9. image element circuit claimed in claim 8, it is characterized in that, in the time keeping at memory capacitance state, one end of memory capacitance is opened and is communicated to the cathodic electricity potential source that provides electric current to luminous by one of them transistor, and in the time of upgrading at memory capacitance state, by another transistor, open and be communicated to another voltage signal.
10. image element circuit claimed in claim 9, is characterized in that, another described voltage signal, and its voltage is for equating to the value of the luminous cathodic electricity potential source that electric current is provided when crossing cabling evanescent voltage.
11. image element circuits claimed in claim 1, is characterized in that, comprise light emitting control transistor, the luminous series connection of this transistor AND gate.
12. image element circuits claimed in claim 1, is characterized in that, state writes transistor open after, data-signal is written to state memory capacitance after can revising by circuit compensation circuit and characteristic optimizing circuit.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410308175.9A CN104078007A (en) | 2014-07-01 | 2014-07-01 | Active light-emitting display device pixel circuit |
| CN201510375007.6A CN104992668A (en) | 2014-07-01 | 2015-06-30 | Active light-emitting display device pixel circuit and drive method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201410308175.9A CN104078007A (en) | 2014-07-01 | 2014-07-01 | Active light-emitting display device pixel circuit |
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| CN104078007A true CN104078007A (en) | 2014-10-01 |
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| CN201410308175.9A Pending CN104078007A (en) | 2014-07-01 | 2014-07-01 | Active light-emitting display device pixel circuit |
| CN201510375007.6A Pending CN104992668A (en) | 2014-07-01 | 2015-06-30 | Active light-emitting display device pixel circuit and drive method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108010487A (en) * | 2016-10-31 | 2018-05-08 | 昆山工研院新型平板显示技术中心有限公司 | A kind of image element circuit and its driving method, display device |
| CN113327541A (en) * | 2020-02-28 | 2021-08-31 | 京东方科技集团股份有限公司 | Array substrate, display panel and display device |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106991968B (en) | 2017-05-27 | 2020-11-27 | 京东方科技集团股份有限公司 | Pixel compensation circuit, pixel compensation method and display device |
| CN109887466B (en) * | 2019-04-19 | 2021-03-30 | 京东方科技集团股份有限公司 | Pixel driving circuit and method and display panel |
| TWI697884B (en) * | 2019-08-20 | 2020-07-01 | 友達光電股份有限公司 | Pixel circuit |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI288377B (en) * | 2004-09-01 | 2007-10-11 | Au Optronics Corp | Organic light emitting display and display unit thereof |
| US7985978B2 (en) * | 2007-04-17 | 2011-07-26 | Himax Technologies Limited | Display and pixel circuit thereof |
| JP5096103B2 (en) * | 2007-10-19 | 2012-12-12 | グローバル・オーエルイーディー・テクノロジー・リミテッド・ライアビリティ・カンパニー | Display device |
| KR20100090527A (en) * | 2009-02-06 | 2010-08-16 | 삼성모바일디스플레이주식회사 | A light emitting display device and a drinving method thereof |
| CN102903333B (en) * | 2012-10-25 | 2015-05-06 | 昆山工研院新型平板显示技术中心有限公司 | Pixel circuit of organic light emitting display |
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2014
- 2014-07-01 CN CN201410308175.9A patent/CN104078007A/en active Pending
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- 2015-06-30 CN CN201510375007.6A patent/CN104992668A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108010487A (en) * | 2016-10-31 | 2018-05-08 | 昆山工研院新型平板显示技术中心有限公司 | A kind of image element circuit and its driving method, display device |
| CN113327541A (en) * | 2020-02-28 | 2021-08-31 | 京东方科技集团股份有限公司 | Array substrate, display panel and display device |
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| CN104992668A (en) | 2015-10-21 |
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Application publication date: 20141001 |