CN106856087A - Image element circuit and its driving method and OLED - Google Patents
Image element circuit and its driving method and OLED Download PDFInfo
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Abstract
In the image element circuit and its driving method and OLED that the present invention is provided, the initialization voltage that the data voltage and the 3rd power supply that the electric current exported as the 6th transistor of driving element in the image element circuit is provided by data wire are provided is determined, and it is unrelated with the threshold voltage of outside supply voltage and the 6th transistor, therefore, it is possible to avoid the brightness disproportionation as caused by threshold voltage deviation and IR change in pressure drop, the image with uniform luminance can be shown using the OLED of the image element circuit and its driving method.
Description
Technical Field
The invention relates to the technical field of flat panel display, in particular to a pixel circuit, a driving method thereof and an organic light emitting display.
Background
An Organic Light Emitting Display (OLED) is a new flat panel display, has many advantages of active light emission, high contrast, fast response speed, light weight, and so on, and is known as a new generation display that can replace a Liquid Crystal Display (LCD).
Please refer to fig. 1, which is a schematic structural diagram of a pixel circuit of an organic light emitting display in the prior art. As shown in fig. 1, the conventional pixel circuit 10 includes a switching transistor T1, a driving transistor T2, and a storage capacitor Cs, a gate of the switching transistor T1 is connected to a driving line Sn, a source of the switching transistor T1 is connected to a data line Dm, a gate of the driving transistor T2, a drain of the switching transistor T1, and a first substrate of the storage capacitor Cs are connected, a source of the driving transistor T2 and a second substrate of the storage capacitor Cs are connected to a first power source ELVDD, a drain of the driving transistor T2 is connected to an anode of the organic light emitting diode OLED, and a cathode of the organic light emitting diode OLED is connected to a second power source ELVSS.
Wherein the switching transistor T1 and the driving transistor T2 are both Thin Film Transistors (TFTs). When the switching transistor T1 is turned on by the driving line Sn, the data voltage Vdata provided by the data line Dm is stored in the storage capacitor Cs via the switching transistor T1, thereby controlling the driving transistor T2 to generate a current to drive the organic light emitting diode OLED to emit light. At this time, the calculation formula of the current Ion flowing between the source and the drain of the driving transistor T2 is:
Ion＝K×(Vsg2-|Vth|)2
where K is the product of the electron mobility, the width-to-length ratio, and the unit area capacitance of the thin film transistor, Vsg2 is the source-gate voltage of the driving transistor T2, i.e., the voltage difference between the source and the gate, and Vth is the threshold voltage of the driving transistor T2.
Since the source voltage Vs2 of the driving transistor T2 is equal to the first power voltage VDD supplied from the first power ELVDD and the gate voltage Vg2 of the driving transistor T2 is equal to the data voltage Vdata supplied from the data line Dm, the source-gate voltage Vsg2 of the driving transistor T2 is equal to VDD-Vdata. The current Ion flowing between the source and the drain of the driving transistor T2 can be calculated according to the following equation:
Ion＝K×(VDD-Vdata-|Vth|)2
it can be seen that the current flowing through the organic light emitting diode OLED is affected by the threshold voltage Vth of the driving transistor T2 and the power voltage VDD actually applied to the pixel circuit 10. When the threshold voltage of the driving transistor T2 and the power supply voltage VDD are changed, the current flowing through the organic light emitting diode OLED is greatly changed, so that the organic light emitting diode OLED still emits light of different brightness for the data signal of the same brightness.
At present, due to the limitation of the manufacturing process, the threshold voltages of the thin film transistors of the respective pixels in the organic light emitting display inevitably have differences, which causes the organic light emitting display to have uneven brightness. Moreover, the power supply wiring connected to the pixel circuit 10 has a certain impedance, and when a current flows through the power supply wiring, the power supply wiring may affect the power supply positive voltage VDD actually reaching the pixel circuit 10, so that the power supply positive voltage VDD received by each pixel circuit 10 is inconsistent, and the phenomenon of uneven brightness is further aggravated. Therefore, it is difficult for the existing organic light emitting display to display an image having uniform brightness.
Therefore, how to solve the problem of uneven brightness of the conventional organic light emitting display caused by the threshold voltage deviation of the driving transistor and the power supply wiring impedance becomes a technical problem to be solved urgently by those skilled in the art.
Disclosure of Invention
The invention aims to provide a pixel circuit, a driving method thereof and an organic light emitting display, so as to solve the problem of uneven brightness of the conventional organic light emitting display caused by threshold voltage deviation of a driving transistor and power supply wiring impedance.
To solve the above problem, the present invention provides a pixel circuit, including:
a first transistor connected between the third node and the fourth node, a gate of which is connected to the second driving line;
a second transistor connected between the fourth node and an anode of the organic light emitting diode, a gate of which is connected to the first driving line;
a third transistor connected between the second node and a third node, a gate of which is connected to the second driving line;
a fourth transistor connected between the data line and the first node, a gate of which is connected to the second driving line;
a fifth transistor connected between the third power source and the third node, a gate of which is connected to the first driving line;
a sixth transistor connected between the first power source and the fourth node, a gate of which is connected to the second node;
a seventh transistor connected between the first node and the third node, a gate of which is connected to the third driving line;
a storage capacitor connected between the first node and the second node; and
and an organic light emitting diode having an anode connected to the drain of the second transistor and a cathode connected to a second power source.
Alternatively, in the pixel circuit, the first power supply is a high-potential pixel power supply, the second power supply is a low-potential pixel power supply, and the first power supply and the second power supply serve as a driving power supply for the organic light emitting diode.
Optionally, in the pixel circuit, the third power supply is configured to provide a reference voltage, and the reference voltage is smaller than the data voltage provided by the data line.
Optionally, in the pixel circuit, the first transistor to the seventh transistor are all P-type thin film transistors.
Optionally, in the pixel circuit, the first driving line controls on and off of the second transistor and the fifth transistor, the second driving line controls on and off of the first transistor, the third transistor and the fourth transistor, and the third driving line controls on and off of the seventh transistor.
Optionally, in the pixel circuit, a second capacitor is further included, and the second capacitor is connected between the second driving line and a second node, and is used for increasing the gate voltage of the sixth transistor.
Optionally, in the pixel circuit, the sixth transistor serves as a driving transistor, and a current supplied to the organic light emitting diode by the sixth transistor is determined by a data voltage supplied by the data line and a reference voltage supplied by the third power supply, regardless of a first power supply voltage supplied by the first power supply, a second power supply voltage supplied by the second power supply, and a threshold voltage of the sixth transistor.
Accordingly, the present invention also provides a driving method of a pixel circuit, the driving method of the pixel circuit including a first period, a second period, a third period, and a fourth period, wherein,
in a first time period, the driving signal provided by the first driving line keeps low level, the driving signal provided by the second driving line changes from high level to low level, the driving signal provided by the third driving line changes from low level to high level, a data signal is written, and meanwhile, the second node is initialized;
in a second time period, the driving signal provided by the first driving line is changed from low level to high level, the driving signal provided by the second driving line is kept at low level, the driving signal provided by the third driving line is kept at high level, the initialization is stopped, and the threshold voltage of the sixth transistor is sampled;
in a third time period, the driving signal provided by the first driving line keeps high level, the driving signal provided by the second driving line changes from low level to high level, the driving signal provided by the third driving line keeps high level, and the writing of the data signal is stopped;
in a fourth time period, the driving signals provided by the first driving line and the third driving line are changed from high level to low level, the driving signal provided by the second driving line is kept at high level, and current is output through the sixth transistor to drive the organic light emitting diode to emit light.
Optionally, in the driving method of the pixel circuit, the second node is initialized, and simultaneously the anode of the organic light emitting diode is initialized.
Correspondingly, the invention also provides an organic light-emitting display which comprises the pixel circuit.
In the pixel circuit, the driving method thereof and the organic light emitting display provided by the present invention, the current output by the sixth transistor as the driving element in the pixel circuit is determined by the data voltage provided by the data line and the initialization voltage provided by the third power supply, regardless of the external power supply voltage and the threshold voltage of the sixth transistor, so that the luminance unevenness caused by the threshold voltage deviation and the IR drop variation can be avoided, and the organic light emitting display using the pixel circuit and the driving method thereof can display an image with uniform luminance.
Drawings
Fig. 1 is a schematic structural diagram of a pixel circuit of an organic light emitting display of the prior art;
fig. 2 is a schematic structural diagram of a pixel circuit according to a first embodiment of the invention;
fig. 3 is a timing diagram of a driving method of a pixel circuit according to a first embodiment of the invention;
fig. 4 is a schematic structural diagram of a pixel circuit according to a second embodiment of the invention.
Detailed Description
A pixel circuit, a driving method thereof, and an organic light emitting display according to the present invention will be described in detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
[ EXAMPLES one ]
Fig. 2 is a schematic structural diagram of a pixel circuit according to a first embodiment of the invention. The pixel circuit 20 includes:
a first transistor M1 connected between the third node N3 and the fourth node N4, a gate thereof being connected to a second driving line S2;
a second transistor M2 connected between the fourth node N4 and the anode of the organic light emitting diode OLED, and having a gate connected to the first driving line S1;
a third transistor M3 coupled between the second node N2 and the third node N3, and having a gate coupled to the second driving line S2;
a fourth transistor M4 connected between the DATA line DATA and the first node N1, and having a gate connected to the second driving line S2;
a fifth transistor M5 connected between the third power source VREF and the third node N3, and having a gate connected to the first driving line S1;
a sixth transistor M6 connected between the first power source ELVDD and the fourth node N4, and having a gate connected to the second node N2;
a seventh transistor M7 connected between the first node N1 and the third node N3, a gate thereof being connected to the third driving line S3;
a storage capacitor C1 connected between the first node N1 and the second node N2; and
an organic light emitting diode OLED has an anode connected to the drain of the second transistor M2 and a cathode connected to a second power source ELVSS.
Specifically, the first power source ELVDD is a high potential pixel power source, the second power source ELVSS is a low potential pixel power source, and the first power source ELVDD and the second power source ELVSS serve as driving power sources of the organic light emitting diode OLED. It should be understood that the high potential pixel power supply herein is relative to the low potential pixel power supply herein, i.e., the potential of the first power supply ELVDD is higher relative to the second power supply ELVSS, which is lower relative to the first power supply ELVDD. The third power source VREF is used to provide a reference voltage VREF, which is a direct-current voltage having a fixed value. In this embodiment, the reference voltage Vref is less than or equal to the DATA voltage Vdata provided by the DATA line DATA.
As shown in fig. 2, the pixel circuit 20 is a 7T1C type circuit structure, and includes 7 transistors and 1 capacitor. Wherein the storage capacitor C1 is connected between the first node N1 and the second node N2 for storing data signals, the sixth transistor M6 serves as a driving transistor of the pixel, a driving current supplied to the organic light emitting diode OLED emitting light with a corresponding luminance according to the driving current is controlled corresponding to the voltage of the second node N2, and the other transistors are switching transistors.
In this embodiment, the first transistor M1 to the seventh transistor M7 are all P-type thin film transistors.
With continued reference to fig. 2, the pixel circuit 20 controls the turning on and off of the second transistor M2 and the fifth transistor M5 through the first driving line S1, controls the turning on and off of the first transistor M1, the third transistor M3 and the fourth transistor M4 through the second driving line S2, controls the turning on and off of the seventh transistor M7 through the third driving line S3, the first driving line S1 is used for controlling the transmission of the initialization voltage, the second driving line S2 is used for controlling the writing of the data voltage and the sampling of the threshold voltage of the driving transistor, and the third driving line S3 is used for initializing and stabilizing the voltage of the first node N1.
When the driving signal supplied from the first driving line S1 transitions to a low level, both the second transistor M2 and the fifth transistor M5 are turned on, and at this time, the initialization voltage VREF supplied from the third power source VREF is applied to the third node N3 through the fifth transistor M5.
When the driving signal supplied from the second driving line S2 transitions to a low level, the first transistor M1, the third transistor M3 and the fourth transistor M4 are all turned on, and the DATA signal supplied from the DATA line DATA is supplied to the first node N1 through the fourth transistor M4.
When the driving signal supplied from the third driving line S3 transitions to a low level, the seventh transistor M7 is turned on, and the initialization voltage VREF supplied from the third power source VREF is applied to the first node N1 through the fifth transistor M5 and the seventh transistor M7.
In this embodiment, the driving current supplied to the organic light emitting diode OLED by the sixth transistor M6 is determined by the DATA voltage Vdata supplied from the DATA line DATA and the initialization voltage VREF supplied from the third power source VREF, regardless of the first power voltage VDD supplied from the first power source ELVDD, the second power voltage supplied from the second power source ELVSS, and the threshold voltage of the third transistor M3. Therefore, even if the threshold voltage of the driving transistor is deviated or the power voltage actually applied to the pixel circuit 20 is changed, the current flowing through the organic light emitting diode OLED is not affected. By adopting the pixel circuit 20, the phenomenon of uneven brightness can be avoided, and the display quality of the display can be improved.
Correspondingly, the invention also provides a driving method of the pixel circuit. Referring to fig. 2 and fig. 3 in combination, the driving method of the pixel circuit includes:
the scan cycle includes a first period T1, a second period T2, a third period T3, and a fourth period T4; wherein,
in the first period T1, the driving signal supplied from the first driving line S1 maintains a low level, the driving signal supplied from the second driving line S2 changes from a high level to a low level, the driving signal supplied from the third driving line S3 changes from a low level to a high level, the data signal is written, and the second node N2 is initialized;
in the second period T2, the driving signal supplied from the first driving line S1 is changed from the low level to the high level, the driving signal supplied from the second driving line S2 is maintained at the low level, the driving signal supplied from the third driving line S3 is maintained at the high level, the initialization is stopped and the threshold voltage of the sixth transistor M6 is sampled;
in the third period T3, the driving signal supplied from the first driving line S1 maintains a high level, the driving signal supplied from the second driving line S2 changes from a low level to a high level, the driving signal supplied from the third driving line S3 maintains a high level, and writing of the data signal is stopped;
during the fourth period T4, the driving signals provided by the first driving line S1 and the third driving line S3 change from high level to low level, the driving signal provided by the second driving line S2 maintains high level, and current is output through the sixth transistor M6 to drive the organic light emitting diode OLED to emit light.
Specifically, in the first period T1, since the driving signal supplied from the second driving line S2 changes from a high level to a low level, the first transistor M1, the third transistor M3 and the fourth transistor M4 controlled by the second driving line S2 all turn off to turn on, and the DATA voltage Vdata supplied from the DATA line DATA is written into the first node N1 through the fourth transistor M4. Meanwhile, since the driving signal supplied from the first driving line S1 is maintained at a low level, the second transistor M2 and the fifth transistor M5 controlled by the first driving line S1 are both in a turned-on state, the initialization voltage VREF supplied from the third power source VREF is supplied to the second node N2 (i.e., the gate of the sixth transistor M6) through the fifth transistor M5 and the third transistor M3, and the initialization voltage VREF supplied from the third power source VREF is supplied to the anode of the organic light emitting diode OLED through the fifth transistor M5, the first transistor M1 and the second transistor M2.
The first time period T1 is an initialization time period during which the anode of the organic light emitting diode OLED and the gate of the sixth transistor M6 are initialized respectively by using the third power source VREF, so that the service life of the organic light emitting diode OLED is prolonged by initialization, and the stress effect of the gate voltage of the sixth transistor M6 is reduced, thereby preparing for writing the next timing data. After initialization, the voltage of the second node N2 is Vref.
In the second period T2, since the driving signal supplied from the first driving line S1 is changed from the low level to the high level, both the second transistor M2 and the fifth transistor M5 controlled by the first driving line S1 are turned on to be turned off, the initialization voltage VREF supplied from the third power source VREF cannot initialize the second node N2 and the fourth node N4 through the fifth transistor M5, since the driving signal supplied from the second driving line S2 is maintained at the low level, the first transistor M1 controlled by the second driving line S2, the third transistor M3 and the fourth transistor M4 are all in the on state, and the DATA voltage Vdata supplied from the DATA line DATA continues to be written into the first node N1 through the fourth transistor M4.
The second period T2 is a programming period during which a voltage corresponding to the DATA signal supplied from the DATA line DATA is stored in the storage capacitor C1. At this time, the voltage of the first node N1 is Vdata, and the voltage of the second node N2 is VDD- | Vth |. Where Vth is the threshold voltage of the sixth transistor M6.
In the third period T3, since the driving signal supplied from the second driving line S2 is changed from a low level to a high level, the first transistor M1, the third transistor M3 and the fourth transistor M4 controlled by the second driving line S2 are all turned on to be turned off, and the DATA voltage Vdata supplied from the DATA line DATA cannot be continuously written into the first node N1 through the fourth transistor M4. Meanwhile, since the driving signals supplied from the first driving line S1 and the third driving line S3 are maintained at a high level, the second transistor M2 and the fifth transistor M5 controlled by the first driving line S1 and the seventh transistor M7 controlled by the third driving line S3 continue to maintain a turn-off state, and the voltages of the first node N1 and the second node N2 are maintained. At this time, the voltage of the first node N1 is Vdata, and the voltage of the second node N2 is VDD- | Vth |.
In the fourth period T4, since the driving signals supplied from the first driving line S1 and the third driving line S3 are both changed from the high level to the low level, the second transistor M2 and the fifth transistor M5 controlled by the first driving line S1 are turned on and the seventh transistor M7 controlled by the third driving line S3 are both turned off to be turned on, the initialization voltage VREF supplied from the third power source VREF is supplied to the first node N1 via the fifth transistor M5 and the seventh transistor M7, and the voltage of the first node N1 is changed from Vdata to VREF. The charge of the first node N1 and the second node N2 remains unchanged due to the coupling of the storage capacitor C1, so the voltage of the second node N2 becomes VDD- | Vth | + (Vref-Vdata). Meanwhile, since the second transistor M2 is turned on, the sixth transistor M6 is connected to the organic light emitting diode OLED, and the sixth transistor M6 supplies a driving current to the organic light emitting diode OLED.
The fourth period T4 is a light emitting period in which the organic light emitting diode OLED emits light corresponding to the driving current. At this time, the source voltage of the sixth transistor M6 is VDD, and the gate voltage of the sixth transistor M6 is equal to the voltage of the second node N2, i.e., VDD- | Vth | + (Vref-Vdata). Therefore, the source-gate voltage Vsg of the sixth transistor M6 (i.e., the voltage difference between the source and the gate of the sixth transistor M6) is calculated by the formula:
vsg — VDD- (VDD- | Vth | + (Vref-Vdata)) formula 1;
the calculation formula of the current Ion flowing through the organic light emitting diode OLED is:
Ion＝K×(Vsg-|Vth|)2formula 2;
wherein K is the product of the electron mobility, the width-to-length ratio and the unit area capacitance of the transistor.
From equation 1 and equation 2, we can obtain:
Ion＝K×(Vdata-Vref)2formula 3;
as can be seen from the expression of formula 3, the current Ion flowing through the organic light emitting diode OLED is related only to the data voltage Vdata, the initialization voltage Vref, and the constant K, and has no relation to the second power voltage ELVSS supplied from the second power source ELVSS and the threshold voltage Vth and the first power voltage VDD of the sixth transistor M6. Therefore, even if the threshold voltage Vth of the sixth transistor M6 is deviated or the power supply voltage VDD is changed, the current Ion flowing through the organic light emitting diode OLED is not affected. Therefore, the pixel circuit 20 and the driving method thereof can avoid the uneven brightness caused by the threshold voltage deviation of the thin film transistor and the power supply voltage variation, thereby improving the display quality of the display. That is, the pixel circuit 20 compensates for variations in threshold voltage and IR drop variations.
In addition, the pixel circuit 20 initializes the gate voltage of the driving transistor and the anode voltage of the organic light emitting diode OLED in the compensation process, so that the attenuation of the driving transistor and the organic light emitting diode OLED is reduced, and the display life of the whole screen body is prolonged.
The working processes of the first, second, third and fourth periods T1, T2, T3 and T4 are repeated to complete the image display function.
[ example two ]
Please refer to fig. 4, which is a schematic structural diagram of a pixel circuit according to a second embodiment of the present invention. The pixel circuit 30 includes:
a first transistor M1 connected between the third node N3 and the fourth node N4, a gate thereof being connected to a second driving line S2;
a second transistor M2 connected between the fourth node N4 and the anode of the organic light emitting diode OLED, and having a gate connected to the first driving line S1;
a third transistor M3 coupled between the second node N2 and the third node N3, and having a gate coupled to the second driving line S2;
a fourth transistor M4 connected between the DATA line DATA and the first node N1, and having a gate connected to the second driving line S2;
a fifth transistor M5 connected between the third power source VREF and the third node N3, and having a gate connected to the first driving line S1;
a sixth transistor M6 connected between the first power source ELVDD and the fourth node N4, and having a gate connected to the second node N2;
a seventh transistor M7 connected between the first node N1 and the third node N3, a gate thereof being connected to the third driving line S3;
a storage capacitor C1 connected between the first node N1 and the second node N2;
a second capacitor C2 connected between the second node N2 and the second drive line S2; and
an organic light emitting diode OLED has an anode connected to the drain of the second transistor M2 and a cathode connected to a second power source ELVSS.
Specifically, as shown in fig. 4, the pixel circuit 30 is a 7T2C type circuit structure, and includes 7 transistors and 2 capacitors.
The difference between the present embodiment and the first embodiment is: the pixel circuit 30 further includes a second capacitor C2, and the second capacitor C2 is connected between the second node N2 and the second driving line S2, and is used for increasing the gate voltage of the sixth transistor M6, thereby reducing the leakage current of the sixth transistor M6. The organic light emitting display using the pixel circuit 30 has a higher contrast ratio and a better display performance.
Correspondingly, the invention also provides an organic light-emitting display which comprises the pixel circuit. Please refer to the above, which is not described herein.
It should be noted that, in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments may be referred to each other.
In summary, in the pixel circuit, the driving method thereof and the organic light emitting display according to the present invention, the current output from the sixth transistor as the driving element in the pixel circuit is determined by the data voltage supplied from the data line and the initialization voltage supplied from the third power source, regardless of the external power source voltage and the threshold voltage of the sixth transistor, so that the luminance unevenness caused by the threshold voltage deviation and the IR drop variation can be avoided, and the organic light emitting display using the pixel circuit and the driving method thereof can display an image with uniform luminance.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.
Claims (10)
1. A pixel circuit, comprising:
a first transistor connected between the third node and the fourth node, a gate of which is connected to the second driving line;
a second transistor connected between the fourth node and an anode of the organic light emitting diode, a gate of which is connected to the first driving line;
a third transistor connected between the second node and a third node, a gate of which is connected to the second driving line;
a fourth transistor connected between the data line and the first node, a gate of which is connected to the second driving line;
a fifth transistor connected between the third power source and the third node, a gate of which is connected to the first driving line;
a sixth transistor connected between the first power source and the fourth node, a gate of which is connected to the second node;
a seventh transistor connected between the first node and the third node, a gate of which is connected to the third driving line;
a storage capacitor connected between the first node and the second node; and
and an organic light emitting diode having an anode connected to the drain of the second transistor and a cathode connected to a second power source.
2. The pixel circuit according to claim 1, wherein the first power source is a high-potential pixel power source, wherein the second power source is a low-potential pixel power source, and wherein the first power source and the second power source serve as a driving power source for the organic light emitting diode.
3. The pixel circuit according to claim 1, wherein the third power supply is configured to provide a reference voltage that is less than or equal to a data voltage provided by the data line.
4. The pixel circuit according to claim 1, wherein the first to seventh transistors are all P-type thin film transistors.
5. The pixel circuit according to claim 1, wherein the first driver line controls on and off of a second transistor and a fifth transistor, wherein the second driver line controls on and off of the first transistor, a third transistor, and a fourth transistor, and wherein the third driver line controls on and off of a seventh transistor.
6. The pixel circuit according to claim 1, further comprising a second capacitor connected between the second drive line and a second node for increasing a gate voltage of the sixth transistor.
7. The pixel circuit according to claim 1, wherein the sixth transistor functions as a driving transistor, and a current supplied to the organic light emitting diode by the sixth transistor is determined by a data voltage supplied from the data line and a reference voltage supplied from the third power source, regardless of the first power source voltage supplied from the first power source, the second power source voltage supplied from the second power source, and a threshold voltage of the sixth transistor.
8. A driving method of the pixel circuit according to any one of claims 1 to 7, wherein the scanning period includes a first period, a second period, a third period, and a fourth period, wherein,
in a first time period, the driving signal provided by the first driving line keeps low level, the driving signal provided by the second driving line changes from high level to low level, the driving signal provided by the third driving line changes from low level to high level, a data signal is written, and meanwhile, the second node is initialized;
in a second time period, the driving signal provided by the first driving line is changed from low level to high level, the driving signal provided by the second driving line is kept at low level, the driving signal provided by the third driving line is kept at high level, the initialization is stopped, and the threshold voltage of the sixth transistor is sampled;
in a third time period, the driving signal provided by the first driving line keeps high level, the driving signal provided by the second driving line changes from low level to high level, the driving signal provided by the third driving line keeps high level, and the writing of the data signal is stopped;
in a fourth time period, the driving signals provided by the first driving line and the third driving line are changed from high level to low level, the driving signal provided by the second driving line is kept at high level, and current is output through the sixth transistor to drive the organic light emitting diode to emit light.
9. The method for driving the pixel circuit according to claim 8, wherein an anode of the organic light emitting diode is initialized simultaneously with initializing the second node.
10. An organic light emitting display, comprising: a pixel circuit as claimed in any one of claims 1 to 7.
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| CN201510889502.9A CN106856087B (en) | 2015-12-07 | 2015-12-07 | Pixel circuit and its driving method and organic light emitting display |
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| CN201510889502.9A CN106856087B (en) | 2015-12-07 | 2015-12-07 | Pixel circuit and its driving method and organic light emitting display |
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| CN106856087A true CN106856087A (en) | 2017-06-16 |
| CN106856087B CN106856087B (en) | 2019-03-08 |
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| CN201510889502.9A Active CN106856087B (en) | 2015-12-07 | 2015-12-07 | Pixel circuit and its driving method and organic light emitting display |
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| CN110070830A (en) * | 2019-04-19 | 2019-07-30 | 深圳市华星光电半导体显示技术有限公司 | Pixel-driving circuit and display panel |
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| CN111402809A (en) * | 2020-05-27 | 2020-07-10 | 上海天马有机发光显示技术有限公司 | Display panel and display device |
| CN111710297A (en) * | 2020-06-22 | 2020-09-25 | 昆山国显光电有限公司 | Pixel driving circuit, driving method thereof and display panel |
| CN115084212A (en) * | 2022-07-27 | 2022-09-20 | 武汉华星光电半导体显示技术有限公司 | Pixel unit |
| TWI849991B (en) * | 2023-06-20 | 2024-07-21 | 大陸商北京歐錸德微電子技術有限公司 | AMOLED pixel compensation circuit, OLED display device and information processing device |
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