CN105448234A - Pixel circuit, driving method thereof, and active matrix organic light emitting display - Google Patents
Pixel circuit, driving method thereof, and active matrix organic light emitting display Download PDFInfo
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- CN105448234A CN105448234A CN201410440215.5A CN201410440215A CN105448234A CN 105448234 A CN105448234 A CN 105448234A CN 201410440215 A CN201410440215 A CN 201410440215A CN 105448234 A CN105448234 A CN 105448234A
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Abstract
In a pixel circuit, a driving method thereof, and an active matrix organic light emitting display that are provided by the invention, when a fourth thin film transistor and a fifth thin film transistor in the pixel circuit are conducted, a gate electrode of a first thin film transistor serving as a driving element can be initialized, a drain electrode of the first thin film transistor and an anode of an organic light emitting diode can also be initialized, in this way, the aging of the first thin film transistor and the organic light emitting diode is reduced, and the service life of the active matrix organic light emitting display is therefore prolonged. Moreover, a first node A of the pixel circuit is charged via a third thin film transistor, a driving current outputted by the first thin film transistor serving as the driving element is independent of the threshold voltage, and thus, the display problem caused by the deviation of the threshold voltage of the thin film transistor can be avoided.
Description
Technical field
The present invention relates to technical field of flat panel display, particularly a kind of image element circuit and driving method thereof and active matrix/organic light emitting display.
Background technology
Active matrix/organic light emitting display (English full name ActiveMatrixOrganicLightingEmittingDisplay, be called for short AMOLED) can self-luminescence, unlike Thin Film Transistor-LCD (English full name ThinFilmTransistorliquidcrystaldisplay, be called for short TFT-LCD) need back light system (backlightsystem) just can light, therefore visibility and brightness are all higher, and more frivolous.At present, active matrix/organic light emitting display is described as the display of new generation that can replace Thin Film Transistor-LCD.
Active matrix/organic light emitting display utilizes thin film transistor (TFT) (English full name ThinFilmTransistor, be called for short TFT), collocation capacitance stores signal, control brightness and the GTG performance of Organic Light Emitting Diode (English full name OrganicLightingEmittingDiode is called for short OLED).But, process deviation meeting and cause the threshold voltage of thin film transistor (TFT) and electron mobility to be different for each pixel, and pixel can be caused relative to same gray scale voltage to launch the light with different GTG as the threshold voltage of the thin film transistor (TFT) of driving element and the deviation of electron mobility, therefore can not show the light with uniform luminance.In order to solve the problem, propose the image element circuit of various compensating threshold voltage.
Please refer to Fig. 1, it is the circuit diagram of the active matrix/organic light emitting display of prior art.As shown in Figure 1, existing active matrix/organic light emitting display 100 comprises: a plurality of data lines, for transmitting the data voltage for display image signals; Many the sweep traces intersected with data line, for transmitting sweep signal; And multiple image element circuit 10, be formed at the region limited by adjacent data line (Dm and Dm+1) and adjacent sweep trace (Gn and Gn+1) respectively, m and n is the integer being greater than 1.
Each image element circuit comprises: the first switch T1, is connected with gate lines G n and data line Dm, the sweep signal provided for responding scanning line Gn and the data voltage that switch data line provides; Second switch T2, its input end accesses an external reset signal Reset, and its output terminal is connected, for response external reset signal Reset by the data voltage initialization of the grid of described the first film transistor M1 with the grid of described the first film transistor M1; The first film transistor M1, its source electrode is connected to supply voltage VDD, and its drain electrode is connected with the input end of organic electroluminescent diode OLED, for responding the data voltage that provides through the first switch and providing drive current to described organic electroluminescent diode OLED; Second thin film transistor (TFT) M2, its grid is connected with the grid of described the first film transistor M1, for compensating the threshold voltage deviation of described the first film transistor M1; And memory capacitance Cs, be provided to the data voltage of the grid of described the first film transistor M1 and the threshold voltage of described second thin film transistor (TFT) M2 for maintaining at predetermined time period.
Wherein, described the first film transistor M1 as driving element, described image element circuit 10 by the grid voltage of the second thin film transistor (TFT) M2 described in described second switch T2 initialization to compensate the threshold voltage of described the first film transistor M1.
But, above-mentioned solution can not carry out initialization to the drain voltage of the anode voltage of described organic electroluminescent diode OLED and described the first film transistor M1, therefore described organic electroluminescent diode OLED and described the first film transistor M1 after a long time use can be aging gradually, causes display inconsistent.And, carry out in initialized process to the grid voltage of described the first film transistor M1, because external reset signal Reset is generally low level, therefore described the first film transistor M1 can thorough conducting, produce larger electric current, described organic electroluminescent diode OLED can send strong light, and then affects the serviceable life of described organic electroluminescent diode OLED and the first film transistor M1.
Summary of the invention
The object of the present invention is to provide a kind of image element circuit and driving method thereof and active matrix/organic light emitting display, to solve short problem in existing active matrix/organic light emitting display serviceable life.
For solving the problem, the invention provides a kind of image element circuit, described image element circuit comprises: the first film transistor, the second thin film transistor (TFT), the 3rd thin film transistor (TFT), the 4th thin film transistor (TFT), the 5th thin film transistor (TFT), Organic Light Emitting Diode and storage capacitors, described the first film transistor is all connected with the anode of described Organic Light Emitting Diode with the drain electrode of the 5th thin film transistor (TFT), the grid of described the first film transistor and the second thin film transistor (TFT), the drain electrode of described second thin film transistor (TFT) and the 4th thin film transistor (TFT), the source electrode of described 5th thin film transistor (TFT) is all connected to first node, between the source electrode that described memory capacitance is connected to described the first film transistor and described node, the drain electrode of described 3rd thin film transistor (TFT) is connected with the source electrode of described second thin film transistor (TFT), the source electrode of described 3rd thin film transistor (TFT) is connected with data line, described 4th thin film transistor (TFT) is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT), the grid of described 3rd thin film transistor (TFT) is connected with the second sweep trace.
Optionally, in described image element circuit, described 4th thin film transistor (TFT) is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT), and described first sweep trace is used for providing the first sweep signal; The grid of described 3rd thin film transistor (TFT) is connected with the second sweep trace, second sweep signal of described second sweep trace for providing; The source electrode of described 3rd thin film transistor (TFT) is connected with data line, and described data line is used for providing data voltage; The source electrode of described the first film transistor is connected with power lead, and described power lead is used for providing supply voltage.
Optionally, in described image element circuit, the source electrode of described 4th thin film transistor (TFT) is connected with a reference power source, and described reference power source is used for for the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode provide initialization voltage.
Optionally, in described image element circuit, described initialization voltage is DC voltage or the ground voltage with fixed value.
Optionally, in described image element circuit, also comprise the 6th thin film transistor (TFT), described the first film transistor is connected with power lead by described 6th thin film transistor (TFT), the grid of described 6th thin film transistor (TFT) is connected with launch-control line, and described launch-control line is used for providing emissioning controling signal.
Optionally, in described image element circuit, the source electrode of described 4th thin film transistor (TFT) is connected with the grid of described 4th thin film transistor (TFT), and the first sweep signal that described first sweep trace provides is as the initialization voltage of the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode.
Accordingly, present invention also offers a kind of driving method of image element circuit, the driving method of described image element circuit comprises:
In the first stage, the first sweep signal that first sweep trace provides becomes low level from high level, and the second sweep signal that the second sweep trace provides keeps high level constant, described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) become conducting by cut-off, carry out initialization by described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) to the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode;
In subordinate phase, the first sweep signal that first sweep trace provides becomes high level from low level, the second sweep signal that second sweep trace provides becomes low level from high level, described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) become cut-off by conducting, described 3rd thin film transistor (TFT) becomes conducting from cut-off, the data voltage that data line provides charges to node, samples to the threshold voltage of described second thin film transistor (TFT) simultaneously;
In the phase III, the first sweep signal that first sweep trace provides keeps high level constant, the second sweep signal that second sweep trace provides becomes high level from low level, described 3rd thin film transistor (TFT) becomes cut-off from conducting, and described the first film transistor output driving current is to drive described organic light-emitting diode.
Optionally, in the driving method of described image element circuit, when described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) conducting, by reference power source, initialization is carried out to the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode.
Optionally, in the driving method of described image element circuit, when described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) conducting, the first sweep signal provided by described first sweep trace carries out initialization to the grid of the anode of described Organic Light Emitting Diode and described the first film transistor and drain electrode.
Optionally, in the driving method of described image element circuit, in the first stage, the emissioning controling signal that launch-control line provides becomes high level from low level; In subordinate phase or phase III, the emissioning controling signal that launch-control line provides becomes low level from high level.
Accordingly, present invention also offers a kind of active matrix/organic light emitting display, described active matrix/organic light emitting display comprises image element circuit as above.
In image element circuit provided by the invention and driving method and active matrix/organic light emitting display thereof, in described image element circuit when the 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) conducting, not only can carry out initialization to the grid of the first film transistor as driving element, can also the drain electrode of the first film transistor and the anode of Organic Light Emitting Diode described in initialization, thus, reduce the aging of described the first film transistor and Organic Light Emitting Diode, and then increase the serviceable life of described active matrix/organic light emitting display.And, after being charged by the first node A of the 3rd thin film transistor (TFT) to described image element circuit, the drive current exported as the first film transistor of driving element and threshold voltage have nothing to do, therefore, it is possible to avoid the display problem caused by the threshold voltage deviation of thin film transistor (TFT).
Accompanying drawing explanation
Fig. 1 is the circuit diagram of the active matrix/organic light emitting display of prior art;
Fig. 2 is the circuit diagram of the image element circuit of the embodiment of the present invention one;
Fig. 3 is the sequential chart of the driving method of the image element circuit of the embodiment of the present invention one;
Fig. 4 is the circuit diagram of the image element circuit of the embodiment of the present invention two;
Fig. 5 is the circuit diagram of the image element circuit of the embodiment of the present invention three;
Fig. 6 is the sequential chart of the driving method of the image element circuit of the embodiment of the present invention three;
Fig. 7 is the sequential chart of the driving method of the image element circuit of the embodiment of the present invention three;
Fig. 8 is the circuit diagram of the image element circuit of the embodiment of the present invention four;
Fig. 9 is the sequential chart of the driving method of the image element circuit of the embodiment of the present invention four;
Figure 10 is the sequential chart of the driving method of the image element circuit of the embodiment of the present invention four.
Embodiment
Propose a kind of image element circuit and driving method and active matrix/organic light emitting display thereof below in conjunction with the drawings and specific embodiments to the present invention to be described in further detail.According to the following describes and claims, advantages and features of the invention will be clearer.It should be noted that, accompanying drawing all adopts the form that simplifies very much and all uses non-ratio accurately, only in order to object that is convenient, the aid illustration embodiment of the present invention lucidly.
[embodiment one]
Please refer to Fig. 2, it is the structural representation of the image element circuit of the embodiment of the present invention one.As shown in Figure 2, described image element circuit 20 comprises: the first film transistor M1, the second thin film transistor (TFT) M2, the 3rd thin film transistor (TFT) M3, the 4th thin film transistor (TFT) M4, the 5th thin film transistor (TFT) M5, Organic Light Emitting Diode OLED and storage capacitors Cst, described the first film transistor M1 is all connected with the anode of described Organic Light Emitting Diode OLED with the drain electrode of the 5th thin film transistor (TFT) M5, the grid of described the first film transistor M1 and the second thin film transistor (TFT) M2, the drain electrode of described second thin film transistor (TFT) M2 and the 4th thin film transistor (TFT) M4, the source electrode of described 5th thin film transistor (TFT) M5 is all connected to first node A, between the source electrode that described memory capacitance Cst is connected to described the first film transistor M1 and described first node A, the drain electrode of described 3rd thin film transistor (TFT) M3 is connected with the source electrode of described second thin film transistor (TFT) M2, the source electrode of described 3rd thin film transistor (TFT) M3 is connected with data line, described 4th thin film transistor (TFT) M4 is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT) M5, the grid of described 3rd thin film transistor (TFT) M3 is connected with the second sweep trace.
Concrete, described image element circuit 20 is a kind of 5T1C type circuit structure, comprises 5 thin film transistor (TFT)s and 1 electric capacity.Wherein, described 4th thin film transistor (TFT) M4 is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT) M5, and described first sweep trace is used for providing the first sweep signal S1.The grid of described 3rd thin film transistor (TFT) M3 is connected with the second sweep trace, the second sweep signal S2 of described second sweep trace for providing.The source electrode of described 3rd thin film transistor (TFT) M3 is connected with data line, and described data line is for providing the data voltage exported by driving chip DATA.The source electrode of described the first film transistor M1 is connected with power lead, and described power lead is used for providing supply voltage VDD, and the drain electrode of described the first film transistor M1 is connected with the anode of described Organic Light Emitting Diode OLED.
The first film transistor M1 as driving element executable operations is used for providing drive current to described Organic Light Emitting Diode OLED, and described Organic Light Emitting Diode OLED responds drive current and luminous.Described memory capacitance Cst is connected between first node A and power lead, for storing corresponding to the voltage of the threshold voltage of described second thin film transistor (TFT) M2 and the data voltage DATA from driving chip output.
The source electrode of described 4th thin film transistor (TFT) M4 is connected with reference power source, and the reference voltage VREF that described reference power source provides is DC voltage or the ground voltage GND with fixed value.When described 4th thin film transistor (TFT) M4 conducting, described reference voltage VREF is applied to first node A, and when described 5th thin film transistor (TFT) M5 conducting, described reference voltage VREF continues to be applied to Section Point B.Described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 conducting simultaneously, reference power source can carry out initialization to the grid of described the first film transistor M1, the drain electrode of described the first film transistor M1 and the anode of described Organic Light Emitting Diode OLED.Visible, described reference power source is used for for the grid of described the first film transistor M1, the drain electrode of described the first film transistor M1 and the anode of described Organic Light Emitting Diode OLED provide initialization voltage.
Preferably, described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 adopts double-gate structure.Adopt double-gate structure can reduce the impact of thin-film transistor drain current on dark-state or contrast.Described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 can also use other to be similar to the structure of double-gate structure, as long as can reduce the impact of thin-film transistor drain current on dark-state or contrast.
Accordingly, present invention also offers a kind of driving method of image element circuit.Incorporated by reference to referring to figs. 2 and 3, the driving method of described image element circuit comprises:
At first stage T1, the first sweep signal S1 that first sweep trace provides becomes low level from high level, and the second sweep signal S2 that the second sweep trace provides keeps high level constant, described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 becomes conducting by cut-off, carries out initialization by described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 to the grid of described the first film transistor M1, the drain electrode of described the first film transistor M1 and the anode of described Organic Light Emitting Diode OLED;
At subordinate phase T2, the first sweep signal S1 that first sweep trace provides becomes high level from low level, the second sweep signal S2 that second sweep trace provides becomes low level from high level, described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 becomes cut-off by conducting, described 3rd thin film transistor (TFT) M3 becomes conducting from cut-off, the data voltage DATA that data line provides charges to first node A, and samples to the threshold voltage of described second thin film transistor (TFT) M2.
At phase III T3, the first sweep signal S1 that first sweep trace provides keeps high level constant, the second sweep signal S2 that second sweep trace provides becomes high level from low level, described 3rd thin film transistor (TFT) M3 becomes cut-off from conducting, and described the first film transistor M1 output driving current is to drive described Organic Light Emitting Diode OLED luminous.
Concrete, the driving method of described image element circuit comprises T1 ~ phase III T3.
At first stage T1, the first sweep signal S1 that first sweep trace provides becomes low level from high level, and the second sweep signal S2 that the second sweep trace provides keeps high level constant, described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 becomes conducting by cut-off, the reference voltage VREF that now reference power source provides arrives the grid of described the first film transistor M1 by described 4th thin film transistor (TFT) M4, and continue to arrive the drain electrode of described the first film transistor M1 and the anode of described Organic Light Emitting Diode OLED by described 5th thin film transistor (TFT) M5, the grid voltage of described the first film transistor M1 is initialized as and low levelly the drain voltage of described the first film transistor M1 and the anode voltage of described Organic Light Emitting Diode OLED is initialized as low level simultaneously.The reference voltage VREF provided due to reference power source is generally negative voltage, and the electric current flowing through described the first film transistor M1 in this stage will flow to reference power source, and can not flow to described Organic Light Emitting Diode OLED.
In the process not only can the grid voltage of the first film transistor M1 described in initialization, and can the drain voltage of the first film transistor M1 and the anode voltage of described Organic Light Emitting Diode OLED described in initialization.And, do not have Organic Light Emitting Diode OLED described in current direction.Thus, the serviceable life of described the first film transistor M1 and described Organic Light Emitting Diode OLED is added.
At subordinate phase T2, the first sweep signal S1 that first sweep trace provides becomes high level from low level, the second sweep signal S2 that second sweep trace provides becomes low level from high level, described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 becomes cut-off by conducting, described 3rd thin film transistor (TFT) M3 becomes conducting from cut-off, the data voltage DATA that data line Dm transmits is by described 3rd thin film transistor (TFT) M3, because the grid voltage of now described the first film transistor M1 is initialized to low level, data voltage DATA will charge to first node A, until the voltage of described first node A reaches DATA-Vth2.
At phase III T3, the first sweep signal S1 that first sweep trace provides keeps high level constant, the second sweep signal S2 that second sweep trace provides becomes high level from low level, described 3rd thin film transistor (TFT) M3 becomes cut-off from conducting, described the first film transistor M1 conducting output driving current, drive described Organic Light Emitting Diode OLED luminous.
Now, the voltage of first node A is DATA-Vth2, and described memory capacitance Cst stores corresponding to the voltage of the threshold voltage of described second thin film transistor (TFT) M2 and the data voltage DATA from driving chip output.Therefore, the gate source voltage Vsg1 of described the first film transistor M1, the voltage difference namely between the grid of described the first film transistor M1 and source electrode is calculated by following formula:
Vsg1=VDD-(DATA-Vth2) formula 1;
Wherein, Vth2 is the absolute value of the threshold voltage of described second thin film transistor (TFT) M2, and VDD represents supply voltage, and DATA represents data voltage.
And the computing formula flowing through the electric current I on of described Organic Light Emitting Diode OLED is:
Ion=K × (Vsg1-Vth1)
2formula 2;
Wherein, Vth1 is the absolute value of the threshold voltage of described the first film transistor M1, and K is that the electron mobility of thin film transistor (TFT), breadth length ratio, unit-area capacitance three are long-pending.
Can be obtained by formula 1 and formula 2:
Ion＝K×(VDD-DATA+Vth2-Vth1)
2。
Generally speaking, the transistor M1 of the first film described in laying out pattern is adjacent with described second thin film transistor (TFT) M2 position, therefore, the threshold voltage of described the first film transistor M1 and the threshold voltage of described second thin film transistor (TFT) M2 basically identical.So the electric current I on flowing through described Organic Light Emitting Diode OLED is:
Ion＝K×(VDD-DATA)
2。
It can thus be appreciated that it doesn't matter to flow through the threshold voltage of the electric current of described Organic Light Emitting Diode OLED and described the first film transistor M1, only relevant with supply voltage VDD, data voltage DATA and constant K.Therefore, described image element circuit and driving method thereof is adopted can to avoid the defect caused because threshold voltage is different completely.Meanwhile, the serviceable life of the first film transistor as driving element and Organic Light Emitting Diode is added.
[embodiment two]
Please refer to Fig. 4, it is the structural representation of the image element circuit of the embodiment of the present invention two.As shown in Figure 4, described image element circuit 30 comprises: the first film transistor M1, the second thin film transistor (TFT) M2, the 3rd thin film transistor (TFT) M3, the 4th thin film transistor (TFT) M4, the 5th thin film transistor (TFT) M5, Organic Light Emitting Diode OLED and storage capacitors Cst, described the first film transistor M1 is all connected with the anode of described Organic Light Emitting Diode OLED with the drain electrode of the 5th thin film transistor (TFT) M5, the grid of described the first film transistor M1 and the second thin film transistor (TFT) M2, the drain electrode of described second thin film transistor (TFT) M2 and the 4th thin film transistor (TFT) M4, the source electrode of described 5th thin film transistor (TFT) M5 is all connected to first node A, between the source electrode that described memory capacitance Cst is connected to described the first film transistor M1 and described first node A, the drain electrode of described 3rd thin film transistor (TFT) M3 is connected with the source electrode of described second thin film transistor (TFT) M2, the source electrode of described 3rd thin film transistor (TFT) M3 is connected with data line, described 4th thin film transistor (TFT) M4 is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT) M5, the grid of described 3rd thin film transistor (TFT) M3 is connected with the second sweep trace.
Concrete, described image element circuit 30 comprises all features of image element circuit 20 described in embodiment one, the difference of the present embodiment and embodiment one is, in described image element circuit 30, the source electrode of the 4th thin film transistor (TFT) M4 is connected with the first sweep trace, instead of is connected with reference power source.Initialization voltage is not provided by reference power source, but is provided by the first sweep trace.
In the present embodiment, the grid voltage of the first film transistor M1 described in the first sweep signal S1 initialization utilizing described first sweep trace to provide, the drain voltage of described the first film transistor M1 and the anode voltage of described Organic Light Emitting Diode OLED.Therefore, the wiring for transmitting reference voltage VERF can reduce.The image element circuit 30 of the present embodiment is applicable to high-resolution product
[embodiment three]
Please refer to Fig. 5, it is the structural representation of the image element circuit of the embodiment of the present invention three.As shown in Figure 5, described image element circuit 40 comprises: the first film transistor M1, the second thin film transistor (TFT) M2, the 3rd thin film transistor (TFT) M3, the 4th thin film transistor (TFT) M4, the 5th thin film transistor (TFT) M5, Organic Light Emitting Diode OLED and storage capacitors Cst, described the first film transistor M1 is all connected with the anode of described Organic Light Emitting Diode OLED with the drain electrode of the 5th thin film transistor (TFT) M5, the grid of described the first film transistor M1 and the second thin film transistor (TFT) M2, the drain electrode of described second thin film transistor (TFT) M2 and the 4th thin film transistor (TFT) M4, the source electrode of described 5th thin film transistor (TFT) M5 is all connected to first node A, between the source electrode that described memory capacitance Cst is connected to described the first film transistor M1 and described first node A, the drain electrode of described 3rd thin film transistor (TFT) M3 is connected with the source electrode of described second thin film transistor (TFT) M2, the source electrode of described 3rd thin film transistor (TFT) M3 is connected with data line, described 4th thin film transistor (TFT) M4 is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT) M5, the grid of described 3rd thin film transistor (TFT) M3 is connected with the second sweep trace.
Concrete, described image element circuit 40 comprises all features of image element circuit 20 described in embodiment one, and the difference of the present embodiment and embodiment one is, described image element circuit 40 is a kind of 6T1C type circuit structure, comprises 6 thin film transistor (TFT)s and 1 electric capacity.As shown in Figure 5, described image element circuit 40 also comprises the 6th thin film transistor (TFT) M6, described the first film transistor M1 is connected with power lead by described 6th thin film transistor (TFT) M6, the grid of described 6th thin film transistor (TFT) M6 is connected with launch-control line, described launch-control line is used for providing emissioning controling signal EM, described 6th thin film transistor (TFT) M6 ends when emissioning controling signal EM is provided to the grid of described 6th thin film transistor (TFT) M6, and conducting in other cases.
Incorporated by reference to reference to figure 6 and Fig. 7, the emissioning controling signal EM that launch-control line provides described in first stage T1 becomes high level from low level, and the emissioning controling signal EM that launch-control line provides described in subordinate phase T2 or phase III T3 becomes low level from high level.
Preferably, described emissioning controling signal EM keeps high level at subordinate phase T2, and described emissioning controling signal EM becomes low level at phase III T3 from high level.
Although at subordinate phase T2, described emissioning controling signal EM is that high level low level has no significant effect for display effect.But, if described emissioning controling signal EM keeps high level at subordinate phase T2, then described 6th thin film transistor (TFT) M6 remain off, therefore, it is possible to avoid described Organic Light Emitting Diode OLED luminous at subordinate phase T2, thus increases the serviceable life of described Organic Light Emitting Diode OLED.
At first stage T1, the first sweep signal S1 that first sweep trace provides becomes low level from high level, and the second sweep signal S2 that the second sweep trace provides keeps high level constant, the emissioning controling signal EM that described launch-control line provides becomes high level from low level, described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 becomes conducting by cut-off, described 6th thin film transistor (TFT) M6 becomes cut-off from conducting, the reference voltage VREF that now reference power source provides arrives the grid of described the first film transistor M1 by described 4th thin film transistor (TFT) M4, and continue to arrive the drain electrode of described the first film transistor M1 and the anode of described Organic Light Emitting Diode OLED by described 5th thin film transistor (TFT) M5, the grid voltage of described the first film transistor M1 is initialized as and low levelly the drain voltage of described the first film transistor M1 and the anode voltage of described Organic Light Emitting Diode OLED is initialized as low level simultaneously.The reference voltage VREF provided due to reference power source is generally negative voltage, and the electric current flowing through described the first film transistor M1 in this stage will flow to reference power source, and can not flow to described Organic Light Emitting Diode OLED.
And at phase III T3, the emissioning controling signal EM that described launch-control line provides is low level, now described 6th thin film transistor (TFT) M6 conducting, the supply voltage VDD that described power lead provides is provided to the source electrode of described the first film transistor M1 through described 6th thin film transistor (TFT) M6, described the first film transistor M1 conducting also according to supply voltage VDD and data voltage DATA output driving current, drives described Organic Light Emitting Diode OLED luminous.
In the present embodiment, the 6th thin film transistor (TFT) M6 is added between power lead and described the first film transistor, described 6th thin film transistor (TFT) M6 is controlled by emissioning controling signal EM, the electric current that may flow to described Organic Light Emitting Diode OLED can be controlled by emissioning controling signal EM, described Organic Light Emitting Diode OLED can be avoided luminous at first stage T1, also described Organic Light Emitting Diode OLED can be avoided luminous at subordinate phase T2, therefore the current drain of VDD can not only be reduced, the serviceable life of described Organic Light Emitting Diode OLED can also be increased further.
[embodiment four]
Please refer to Fig. 8, it is the structural representation of the image element circuit of the embodiment of the present invention four.As shown in Figure 8, described image element circuit 50 comprises: the first film transistor M1, the second thin film transistor (TFT) M2, the 3rd thin film transistor (TFT) M3, the 4th thin film transistor (TFT) M4, the 5th thin film transistor (TFT) M5, Organic Light Emitting Diode OLED and storage capacitors Cst, described the first film transistor M1 is all connected with the anode of described Organic Light Emitting Diode OLED with the drain electrode of the 5th thin film transistor (TFT) M5, the grid of described the first film transistor M1 and the second thin film transistor (TFT) M2, the drain electrode of described second thin film transistor (TFT) M2 and the 4th thin film transistor (TFT) M4, the source electrode of described 5th thin film transistor (TFT) M5 is all connected to first node A, between the source electrode that described memory capacitance Cst is connected to described the first film transistor M1 and described first node A, the drain electrode of described 3rd thin film transistor (TFT) M3 is connected with the source electrode of described second thin film transistor (TFT) M2, the source electrode of described 3rd thin film transistor (TFT) M3 is connected with data line, described 4th thin film transistor (TFT) M4 is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT) M5, the grid of described 3rd thin film transistor (TFT) M3 is connected with the second sweep trace.
Concrete, described image element circuit 50 comprises all features of image element circuit 40 described in embodiment three, the difference of the present embodiment and embodiment three is, in described image element circuit 50, the source electrode of the 4th thin film transistor (TFT) M4 is connected with the first sweep trace, instead of is connected with reference power source.Initialization voltage is not provided by reference power source, but is provided by the first sweep trace.As shown in Figure 8, the source electrode of described 4th thin film transistor (TFT) M4 is all connected with the first sweep trace with grid, and described first sweep trace is used for providing the first sweep signal.
Incorporated by reference to reference to figure 9 and Figure 10, the emissioning controling signal EM that launch-control line provides described in first stage T1 becomes high level from low level, and the emissioning controling signal EM that launch-control line provides described in subordinate phase T2 or phase III T3 becomes low level from high level.
Preferably, described emissioning controling signal EM keeps high level at subordinate phase T2, and described emissioning controling signal EM becomes low level at phase III T3 from high level.
Although at subordinate phase T2, described emissioning controling signal EM is that high level low level has no significant effect for display effect.But, if described emissioning controling signal EM keeps high level at subordinate phase T2, then described 6th thin film transistor (TFT) M6 remain off, therefore, it is possible to avoid described Organic Light Emitting Diode OLED luminous at subordinate phase T2, thus increases the serviceable life of described Organic Light Emitting Diode OLED.
At first stage T1, the first sweep signal S1 that first sweep trace provides becomes low level from high level, and the second sweep signal S2 that the second sweep trace provides keeps high level constant, the emissioning controling signal EM that described launch-control line provides becomes high level from low level, described 4th thin film transistor (TFT) M4 and the 5th thin film transistor (TFT) M5 becomes conducting by cut-off, described 6th thin film transistor (TFT) M6 becomes cut-off from conducting, now the first sweep signal S1 arrives the grid of described the first film transistor M1 by described 4th thin film transistor (TFT) M4, and continue to arrive the drain electrode of described the first film transistor M1 and the anode of described Organic Light Emitting Diode OLED by described 5th thin film transistor (TFT) M5, the grid voltage of described the first film transistor M1 is initialized as and low levelly the drain voltage of described the first film transistor M1 and the anode voltage of described Organic Light Emitting Diode OLED is initialized as low level simultaneously.Because the voltage of now the first sweep signal S1 is low level, the electric current flowing through described the first film transistor M1 in this stage will flow to the first sweep trace, and can not flow to described Organic Light Emitting Diode OLED.
In the present embodiment, the grid voltage of the first film transistor M1 described in the first sweep signal S1 initialization utilizing described first sweep trace to provide, the drain voltage of described the first film transistor M1 and the anode voltage of described Organic Light Emitting Diode OLED.Therefore, the wiring for transmitting reference voltage VERF can reduce.The image element circuit 50 of the present embodiment is applicable to high-resolution product.
Accordingly, present invention also offers a kind of active matrix/organic light emitting display, described active matrix/organic light emitting display comprises image element circuit as above.
To sum up, in image element circuit provided by the invention and driving method and active matrix/organic light emitting display thereof, in described image element circuit when the 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) conducting, not only can carry out initialization to the grid of the first film transistor as driving element, can also the drain electrode of the first film transistor and the anode of Organic Light Emitting Diode described in initialization, thus, reduce the aging of described the first film transistor and Organic Light Emitting Diode, and then increase the serviceable life of described active matrix/organic light emitting display.And, after being charged by the first node A of the 3rd thin film transistor (TFT) to described image element circuit, the drive current exported as the first film transistor of driving element and threshold voltage have nothing to do, therefore, it is possible to avoid the display problem caused by the threshold voltage deviation of thin film transistor (TFT).
Foregoing description is only the description to present pre-ferred embodiments, any restriction not to the scope of the invention, and any change that the those of ordinary skill in field of the present invention does according to above-mentioned disclosure, modification, all belong to the protection domain of claims.
Claims (10)
1. an image element circuit, is characterized in that, comprising: the first film transistor, the second thin film transistor (TFT), the 3rd thin film transistor (TFT), the 4th thin film transistor (TFT), the 5th thin film transistor (TFT), Organic Light Emitting Diode and storage capacitors, described the first film transistor is all connected with the anode of described Organic Light Emitting Diode with the drain electrode of the 5th thin film transistor (TFT), the grid of described the first film transistor and the second thin film transistor (TFT), the drain electrode of described second thin film transistor (TFT) and the 4th thin film transistor (TFT), the source electrode of described 5th thin film transistor (TFT) is all connected to first node, between the source electrode that described memory capacitance is connected to described the first film transistor and described node, the drain electrode of described 3rd thin film transistor (TFT) is connected with the source electrode of described second thin film transistor (TFT), the source electrode of described 3rd thin film transistor (TFT) is connected with data line, described 4th thin film transistor (TFT) is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT), the grid of described 3rd thin film transistor (TFT) is connected with the second sweep trace.
2. image element circuit as claimed in claim 1, it is characterized in that, described 4th thin film transistor (TFT) is all connected with the first sweep trace with the grid of the 5th thin film transistor (TFT), and described first sweep trace is used for providing the first sweep signal; The grid of described 3rd thin film transistor (TFT) is connected with the second sweep trace, second sweep signal of described second sweep trace for providing; The source electrode of described 3rd thin film transistor (TFT) is connected with data line, and described data line is used for providing data voltage; The source electrode of described the first film transistor is connected with power lead, and described power lead is used for providing supply voltage.
3. image element circuit as claimed in claim 2, it is characterized in that, the source electrode of described 4th thin film transistor (TFT) is connected with a reference power source, and described reference power source is used for for the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode provide initialization voltage; Described initialization voltage is DC voltage or the ground voltage with fixed value.
4. image element circuit as claimed in claim 2, it is characterized in that, the source electrode of described 4th thin film transistor (TFT) is connected with the grid of described 4th thin film transistor (TFT), and the first sweep signal that described first sweep trace provides is as the initialization voltage of the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode.
5. the image element circuit as described in claim 3 or 4, it is characterized in that, also comprise the 6th thin film transistor (TFT), described the first film transistor is connected with power lead by described 6th thin film transistor (TFT), the grid of described 6th thin film transistor (TFT) is connected with launch-control line, and described launch-control line is used for providing emissioning controling signal.
6. a driving method for the image element circuit according to any one of claim 1 to 5, is characterized in that, comprising:
In the first stage, the first sweep signal that first sweep trace provides becomes low level from high level, and the second sweep signal that the second sweep trace provides keeps high level constant, described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) become conducting by cut-off, carry out initialization by described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) to the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode;
In subordinate phase, the first sweep signal that first sweep trace provides becomes high level from low level, the second sweep signal that second sweep trace provides becomes low level from high level, described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) become cut-off by conducting, described 3rd thin film transistor (TFT) becomes conducting from cut-off, the data voltage that data line provides charges to node, samples to the threshold voltage of described second thin film transistor (TFT) simultaneously;
In the phase III, the first sweep signal that first sweep trace provides keeps high level constant, the second sweep signal that second sweep trace provides becomes high level from low level, described 3rd thin film transistor (TFT) becomes cut-off from conducting, and described the first film transistor output driving current is to drive described organic light-emitting diode.
7. the driving method of image element circuit as claimed in claim 6, it is characterized in that, when described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) conducting, by reference power source, initialization is carried out to the grid of described the first film transistor, the drain electrode of described the first film transistor and the anode of described Organic Light Emitting Diode.
8. the driving method of image element circuit as claimed in claim 6, it is characterized in that, when described 4th thin film transistor (TFT) and the 5th thin film transistor (TFT) conducting, the first sweep signal provided by described first sweep trace carries out initialization to the grid of the anode of described Organic Light Emitting Diode and described the first film transistor and drain electrode.
9. the driving method of image element circuit as claimed in claim 6, it is characterized in that, in the first stage, the emissioning controling signal that launch-control line provides becomes high level from low level; In subordinate phase or phase III, the emissioning controling signal that launch-control line provides becomes low level from high level.
10. an active matrix/organic light emitting display, is characterized in that, comprising: the image element circuit according to any one of claim 1 to 5.
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Effective date of registration: 20201209 Address after: No.146 Tianying Road, high tech Zone, Chengdu, Sichuan Province Patentee after: Chengdu CHENXIAN photoelectric Co.,Ltd. Address before: No. 188, CHENFENG Road, Kunshan high tech Zone, Kunshan City, Suzhou City, Jiangsu Province Patentee before: Kunshan New Flat Panel Display Technology Center Co.,Ltd. Patentee before: KunShan Go-Visionox Opto-Electronics Co.,Ltd. |