CN204229810U - Pixel-driving circuit, display panel and display device - Google Patents
Pixel-driving circuit, display panel and display device Download PDFInfo
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- CN204229810U CN204229810U CN201420766721.9U CN201420766721U CN204229810U CN 204229810 U CN204229810 U CN 204229810U CN 201420766721 U CN201420766721 U CN 201420766721U CN 204229810 U CN204229810 U CN 204229810U
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Abstract
The utility model provides a kind of pixel-driving circuit, display panel and display device.Described pixel-driving circuit comprises driving transistors, switch control unit and threshold control unit, and wherein, driving transistors is floating transistor; Threshold control unit is within each display cycle, when sweep signal is effective, control, by programmable voltage modulation signal, the current potential of the control gate of this driving transistors is charged to predetermined threshold controlling potential, and the current potential controlling the control gate maintaining driving transistors when sweep signal is invalid is predetermined threshold controlling potential, to be controlled in predetermined threshold voltage range by the threshold voltage of driving transistors.The OLED pixel circuit that the utility model solves existing voltage driven mode due to crystalline stability in the manufacture craft process of transistor and doping homogeneity, thus make the threshold voltage of portion of transistor in OLED pixel circuit that drift occur and cause easily produce picture chromenence or the uneven problem of gray scale when display frame.
Description
Technical field
The utility model relates to display field, particularly relates to a kind of pixel-driving circuit, display panel and display device.
Background technology
OLED (Organic Light-Emitting Diode, Organic Light Emitting Diode) device has active illuminating, and shock resistance is good, and visual angle is wide, operating temperature is wide, contrast is high, can realize the advantages such as Flexible Displays, is acknowledged as the regeneration product of field of liquid crystal display, simultaneously, along with luminescence efficiency and life-span rise year by year, OLED, except can be used for display, also can be widely used in lighting field.
The basic structure of OLED is be anode and metal level with transparent electrode layer on substrate is evaporation hole injection layer, hole transmission layer and electron injecting layer successively between negative electrode, and each layer be arranged between transparent electrode layer and metal level is organic semiconducting materials.When OLED gets suitable electric power supply, hole and electronics inject from anode and negative electrode respectively, then luminescent layer is conducted to through hole and electron transfer layer, and in luminous material layer generation radiation recombination, be in excited state after the outer-shell electron absorption energy of luminous material layer, radiation transistion realizes luminous.
Common OLED has voltage driven and electric current to drive two kinds of modes.Voltage driving mode circuit is simple, simple to operate, but easily because the uneven threshold voltage of each transistor that causes of the doping of OLED crystallization of polysilicon in manufacture craft process is different, cause the display frame Mura on electrical mechanism (colourity or gray scale uneven) bad.Due to the crystallization of polysilicon and doping process not easily controlled, easily make the threshold voltage of each transistor inconsistent, threshold voltage drifts about, when picture shows, the electric current driving OLED device that cannot reach required for us effectively shows, and causes the Mura badness that picture occurs on electrical mechanism.
As shown in Figure 1, for the pixel-driving circuit figure that prior art provides, this pixel-driving circuit comprises switching transistor T1, driving transistors T2 and memory capacitance C, and wherein switching transistor T1 is connected with data line Data, and driving transistors T2 is connected with OLED O1.The grid of driving transistors T2 is connected with memory capacitance C.When scanning current sweep trace Scan, the switching transistor T1 be expert at opens, and charges in the process that data line Data opens at switching transistor T1 to memory capacitance C, preserve data-signal, driving transistors T2 opens simultaneously, drives OLED O1, makes it luminous.During sweep trace scanning next stage, also when namely switching transistor T1 is in closed condition, memory capacitance C completes the storage action of electric charge within the scan period, within switching transistor T1 closing time, continue the original electromotive force of the grid keeping driving transistors T2, thus it is continual and steady luminous in one-period to reach driving OLED device O1.In actual fabrication process, due to the crystallization of polysilicon and doping process not easily controlled, easily make the threshold voltage of each transistor inconsistent, threshold voltage drifts about, and causes the Mura badness that picture occurs on electrical mechanism.
Utility model content
Fundamental purpose of the present utility model is to provide a kind of pixel-driving circuit, display panel and display device, the OLED pixel circuit solving existing voltage driven mode due to crystalline stability in the manufacture craft process of transistor and doping homogeneity, thus make the threshold voltage of portion of transistor in OLED pixel circuit that drift occur and cause easily produce picture chromenence or the uneven problem of gray scale when display frame.
In order to achieve the above object, the utility model provides a kind of pixel-driving circuit, comprises driving transistors, switch control unit and threshold control unit, and wherein, described driving transistors is floating transistor;
Described driving transistors, the first pole access driving voltage, the second pole is connected with OLED;
Described switch control unit, access sweep signal and data-signal respectively, and be connected with the signal grid of described driving transistors, for within each display cycle, when described sweep signal is effective, control, by described data-signal, the current potential of the signal grid of this driving transistors is charged to predetermined switch controlling potential, and the current potential controlling the signal grid maintaining described driving transistors when described sweep signal is invalid is predetermined switch controlling potential, drives described OLED to control described driving transistors conducting;
Described threshold control unit, access described sweep signal and programmable voltage modulation signal respectively, and be connected with the control gate of described driving transistors, for within each display cycle, when described sweep signal is effective, control, by described programmable voltage modulation signal, the current potential of the control gate of this driving transistors is charged to predetermined threshold controlling potential, and the current potential controlling the control gate maintaining described driving transistors when described sweep signal is invalid is predetermined threshold controlling potential, so that the threshold voltage of described driving transistors is controlled in predetermined threshold voltage range.
During enforcement, described switch control unit comprises:
The first transistor, grid accesses described sweep signal, and described data-signal is accessed in the first pole, and the second pole is connected with the signal grid of described driving transistors;
And the first memory capacitance, first end is connected with the second pole of described the first transistor, the second end ground connection.
During enforcement, described threshold control unit comprises:
Transistor seconds, grid accesses described sweep signal, the first pole access programmable voltage modulation signal, and the second pole is connected with the control gate of described driving transistors;
And the second memory capacitance, first end is connected with the second pole of described transistor seconds, the second end ground connection.
The utility model additionally provides a kind of display device, comprises above-mentioned display panel.
Compared with prior art, pixel-driving circuit described in the utility model, display panel and display device, adopt floating transistor as driving transistors, utilize the characteristic that the threshold value of floating transistor is controlled, threshold control unit utilizes the outside threshold voltage of programmable voltage modulation signal to floating transistor to regulate and control, even if reach the phenomenon that driving transistors produces threshold drift in manufacture craft, also the threshold value reaching driving transistors by external means controls in predetermined threshold voltage range, picture chromenence or gray scale uneven problem is easily produced during effective solution display frame.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of existing pixel-driving circuit;
Fig. 2 is the structural representation of the pixel-driving circuit described in the utility model embodiment;
Fig. 3 is the circuit diagram of the pixel-driving circuit described in the utility model one specific embodiment;
Fig. 3 A is the working timing figure of the pixel-driving circuit described in specific embodiment as shown in Figure 3;
Fig. 4 is the signal timing diagram of pixel-driving circuit as shown in Figure 3 in the debug phase;
Fig. 5 is the signal timing diagram of pixel-driving circuit as shown in Figure 3 at working stage.
Embodiment
For making the technical problems to be solved in the utility model, technical scheme and advantage clearly, be described in detail below in conjunction with the accompanying drawings and the specific embodiments.
As shown in Figure 2, the pixel-driving circuit described in the utility model embodiment, comprises driving transistors TD, switch control unit 21 and threshold control unit 22, and wherein, described driving transistors TD is floating transistor;
Described driving transistors TD, the first pole access driving voltage Vdd, the second pole is connected with the anode of OLED O1;
Described switch control unit 21, access the sweep signal on sweep trace Scan and the data-signal on data line Data respectively, and be connected with the signal grid of described driving transistors TD, for within each display cycle, when described sweep signal is effective, control, by described data-signal, the current potential of the signal grid of this driving transistors TD is charged to predetermined switch controlling potential, and the current potential controlling the signal grid maintaining described driving transistors TD when described sweep signal is invalid is predetermined switch controlling potential, described OLED O1 is driven to control described driving transistors conducting,
Described threshold control unit 22, access sweep signal and programmable voltage modulation signal Vadj on described sweep trace Scan respectively, and be connected with the control gate of described driving transistors TD, for within each display cycle, when described sweep signal is effective, control, by described programmable voltage modulation signal Vadj, the current potential of the control gate of this driving transistors TD is charged to predetermined threshold controlling potential, and the current potential controlling the control gate maintaining described driving transistors TD when described sweep signal is invalid is predetermined threshold controlling potential, so that the threshold voltage of described driving transistors TD is controlled in predetermined threshold voltage range,
The negative electrode of OLED O1 holds GND to be connected with ground.
Pixel-driving circuit described in the utility model embodiment, adopt floating transistor as driving transistors, utilize the characteristic that the threshold value of floating transistor is controlled, threshold control unit utilizes the outside threshold voltage of programmable voltage modulation signal Vadj to floating transistor to regulate and control, even if reach the phenomenon that driving transistors produces threshold drift in manufacture craft, also the threshold value reaching driving transistors by external means controls in predetermined threshold voltage range, easily produces picture chromenence or gray scale uneven problem when effectively solving display frame.
In fig. 2, first of TD very drains, the second very source electrode of TD.
The transistor adopted in all embodiments of the utility model can be all thin film transistor (TFT) or field effect transistor or the identical device of other characteristics.In the utility model embodiment, for distinguishing transistor the two poles of the earth except grid, wherein first can be extremely source electrode or drain electrode, and second can be extremely drain electrode or source electrode.In addition, distinguish transistor can be divided into n-type transistor or p-type transistor according to the characteristic of transistor.In the driving circuit that the utility model embodiment provides; all crystals Guan Jun is the explanation carried out for p-type transistor; it is conceivable that be that those skilled in the art can expect, therefore also in embodiment protection domain of the present utility model easily not making under creative work prerequisite when adopting n-type transistor to realize.
In the specific implementation, described switch control unit can comprise:
The first transistor, grid accesses described sweep signal, and described data-signal is accessed in the first pole, and the second pole is connected with the signal grid of described driving transistors;
And the first memory capacitance, first end is connected with the second pole of described the first transistor, the second end ground connection.
In the specific implementation, described threshold control unit comprises:
Transistor seconds, grid accesses described sweep signal, and the first pole is connected with programmable voltage modulation signal line, and the second pole is connected with the control gate of described driving transistors;
And the second memory capacitance, first end is connected with the second pole of described transistor seconds, the second end ground connection.
As shown in Figure 3, according to a kind of embodiment, described switch control unit comprises the first transistor T1 and the first memory capacitance C1, wherein,
Described the first transistor T1 is n-type transistor;
Described the first transistor T1, grid is connected with described sweep trace Scan, and drain electrode is connected with data line Data, and source electrode is connected with the signal grid of driving transistors TD;
Described first memory capacitance C1, first end is connected with the source electrode of described the first transistor T1, and the second end holds GND to be connected with ground;
Described threshold control unit comprises transistor seconds T2 and the second memory capacitance C2, wherein,
Described transistor seconds T2 is n-type transistor;
Described transistor seconds T2, grid is connected with described sweep trace Scan, drain electrode access programmable voltage modulation signal Vadj, and source electrode is connected with the control gate of described driving transistors TD;
Described second memory capacitance C2, first end is connected with the source electrode of described transistor seconds T2, and the second end holds GND to be connected with ground;
In figure 3, A point is the node be connected with the signal grid of TD, and B point is the node be connected with the control gate of TD.
When practical operation, the first transistor T1 and/or transistor seconds T2 can replace with p-type transistor, only need change to Low level effective by corresponding for sweep signal, transistor types be replaced by those skilled in the art's common technology means, do not repeat them here.
The principle of work of the pixel-driving circuit described in specific embodiment is as shown in Figure 3 as follows: in each display cycle: as shown in Figure 3A,
At pre-charging stage S1, sweep signal on sweep trace Scan is high level, the first transistor T1 and transistor seconds T2 opens, by the data-signal on data line Data, the first memory capacitance C1 is charged, by programmable voltage modulation signal Vadj, C2 is charged, the current potential of A point and the potential duration of B point raise, until T1 disconnects;
At glow phase S2, the sweep signal saltus step on sweep trace Scan is low level, and the first transistor T1 and transistor seconds T2 disconnects, and the current potential that the first memory capacitance C1 maintains the signal grid of driving transistors TD is constant, and namely the current potential of A point remains unchanged; Driving transistors TD constant conduction is luminous with driving OLED device O1, until next display cycle; The current potential that second memory capacitance C2 maintains the control gate of driving transistors TD is constant, and namely the current potential of B point remains unchanged, to control the threshold voltage unchanged of driving transistors TD, until next display cycle;
At reseting stage S3, sweep signal saltus step on sweep trace Scan is high level, and the data-signal on data line Data is maintained low level until the next display cycle, T1 and T2 be conducting, C1 and C2 starts electric discharge, resets with the current potential of the control gate of the current potential and TD that make the signal grid of TD.
The programmable voltage modulation signal Vadj of the threshold voltage unchanged how determining to control driving transistors TD is described below by Fig. 4 and Fig. 5:
As shown in Figure 4, the pixel-driving circuit described in the utility model embodiment is in the debug phase, able to programme at debug phase Vadj, finally obtains by debugging repeatedly the threshold voltage vt h uniform programmable voltage modulation signal Vadj making floating transistor;
As shown in Figure 5, after determining the threshold voltage vt h uniform programmable voltage modulation signal Vadj that can make floating transistor, control the pixel-driving circuit described in the utility model embodiment is formally started working.
It should be noted that, Fig. 4 and Fig. 5 is that the sequential chart of each signal of debug phase when choosing programmable voltage modulation signal Vadj is as Fig. 4, the threshold voltage of TD (namely threshold voltage does not exist drift) in predetermined threshold voltage range can be made to choose through test of many times, determine, after optimum Vadj, to adopt this Vadj when real work through test.
In figures 4 and 5, Vdata is the data-signal on data line Data, and Vscan-1 is the first row sweep signal, and Vscan-n is n-th line sweep signal, n be greater than 1 integer.
Display panel described in the utility model embodiment, comprises data line, sweep trace and light-emitting component, and described sweep trace exports sweep signal, described data line outputting data signals; Described display panel also comprises above-mentioned pixel-driving circuit;
The switch element that described sweep trace comprises with described pixel-driving circuit respectively and control module are connected;
The switch element that described data line comprises with described pixel-driving circuit is connected;
Second pole of the driving transistors that described light-emitting component comprises with described pixel-driving circuit is connected.
Display device described in the utility model embodiment comprises above-mentioned display panel.
Display panel described in the utility model embodiment is preferably AMOLED (ActiveMatrix/Organic Light Emitting Diode, active matrix organic light-emitting diode) display panel, the display device described in the utility model embodiment is preferably AMOLED display device.
The above is preferred implementation of the present utility model; should be understood that; for those skilled in the art; under the prerequisite not departing from principle described in the utility model; can also make some improvements and modifications, these improvements and modifications also should be considered as protection domain of the present utility model.
Claims (5)
1. a pixel-driving circuit, is characterized in that, comprises driving transistors, switch control unit and threshold control unit, and wherein, described driving transistors is floating transistor;
Described driving transistors, the first pole access driving voltage, the second pole is connected with OLED;
Described switch control unit, access sweep signal and data-signal respectively, and be connected with the signal grid of described driving transistors, for within each display cycle, when described sweep signal is effective, control, by described data-signal, the current potential of the signal grid of this driving transistors is charged to predetermined switch controlling potential, and the current potential controlling the signal grid maintaining described driving transistors when described sweep signal is invalid is predetermined switch controlling potential, drives described OLED to control described driving transistors conducting;
Described threshold control unit, access described sweep signal and programmable voltage modulation signal respectively, and be connected with the control gate of described driving transistors, for within each display cycle, when described sweep signal is effective, control, by described programmable voltage modulation signal, the current potential of the control gate of this driving transistors is charged to predetermined threshold controlling potential, and the current potential controlling the control gate maintaining described driving transistors when described sweep signal is invalid is predetermined threshold controlling potential, so that the threshold voltage of described driving transistors is controlled in predetermined threshold voltage range.
2. pixel-driving circuit structure according to claim 1, is characterized in that, described switch control unit comprises:
The first transistor, grid accesses described sweep signal, and described data-signal is accessed in the first pole, and the second pole is connected with the signal grid of described driving transistors;
And the first memory capacitance, first end is connected with the second pole of described the first transistor, the second end ground connection.
3. pixel-driving circuit according to claim 2, is characterized in that, described threshold control unit comprises:
Transistor seconds, grid accesses described sweep signal, and described programmable voltage modulation signal is accessed in the first pole, and the second pole is connected with the control gate of described driving transistors;
And the second memory capacitance, first end is connected with the second pole of described transistor seconds, the second end ground connection.
4. a display panel, comprises data line, sweep trace and light-emitting component, and described sweep trace exports sweep signal, described data line outputting data signals; It is characterized in that, described display panel also comprises the pixel-driving circuit as described in claim arbitrary in claims 1 to 3;
The switch element that described sweep trace comprises with described pixel-driving circuit respectively and control module are connected;
The switch element that described data line comprises with described pixel-driving circuit is connected;
Second pole of the driving transistors that described light-emitting component comprises with described pixel-driving circuit is connected.
5. a display device, is characterized in that, comprises display panel as claimed in claim 4.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420766721.9U CN204229810U (en) | 2014-12-08 | 2014-12-08 | Pixel-driving circuit, display panel and display device |
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| CN201420766721.9U CN204229810U (en) | 2014-12-08 | 2014-12-08 | Pixel-driving circuit, display panel and display device |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104376815A (en) * | 2014-12-08 | 2015-02-25 | 京东方科技集团股份有限公司 | Pixel driving circuit, pixel driving method, display panel and display device |
| CN107068030A (en) * | 2015-11-18 | 2017-08-18 | 三星显示有限公司 | Scan line driver and the display device including the scan line driver |
| CN112331150A (en) * | 2020-11-05 | 2021-02-05 | Tcl华星光电技术有限公司 | Display device and light-emitting panel |
-
2014
- 2014-12-08 CN CN201420766721.9U patent/CN204229810U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104376815A (en) * | 2014-12-08 | 2015-02-25 | 京东方科技集团股份有限公司 | Pixel driving circuit, pixel driving method, display panel and display device |
| CN107068030A (en) * | 2015-11-18 | 2017-08-18 | 三星显示有限公司 | Scan line driver and the display device including the scan line driver |
| CN107068030B (en) * | 2015-11-18 | 2021-07-02 | 三星显示有限公司 | Scanning line driver and display device including the same |
| CN112331150A (en) * | 2020-11-05 | 2021-02-05 | Tcl华星光电技术有限公司 | Display device and light-emitting panel |
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