CN110544458B - A pixel circuit, a driving method thereof, and a display device - Google Patents

Abstract

The invention discloses a pixel circuit, a driving method thereof and a display device. The pixel circuit comprises a driving transistor, a data writing module, a light-emitting control module, a threshold compensation module and a light-emitting device; the data writing module provides a signal of a data signal end to the second pole of the driving transistor; the threshold compensation module resets the gate of the driving transistor and compensates the threshold voltage of the driving transistor; the light-emitting control module provides the signal of the first voltage terminal to the first pole of the driving transistor, and drives the The second electrode of the transistor is connected with the light-emitting device; the driving transistor is used for generating a driving current to drive the light-emitting device to emit light. The pixel circuit provided by the embodiment of the present invention can compensate the threshold voltage of the driving transistor, so that the driving current for driving the light-emitting device to emit light is not affected by the threshold voltage of the driving module. In addition, the voltage of the first voltage terminal can be compensated, so that the driving current is not affected by the voltage of the first voltage terminal.

Description

A pixel circuit, a driving method thereof, and a display device

technical field

The present invention relates to the field of display technology, and in particular, to a pixel circuit, a driving method thereof and a display device.

Background technique

Organic Light Emitting Diode (OLED) panels have the characteristics of flexibility, high contrast, and low power consumption, and have received extensive attention. Among them, the pixel circuit is the core technical content of the OLED panel, which has important research significance. Generally, the OLED in the OLED panel is driven to emit light by the current generated by the driving transistor in the pixel circuit. However, due to the limitation of the process and the increase of the use time, the threshold voltage Vth of the driving transistor will drift to different degrees, so that the OLED panel has the problem of uneven OLED light-emitting brightness. Moreover, due to the existence of IRDrop (voltage drop) in the OLED panel, the OLED panel will also have the problem of uneven OLED luminance.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a pixel circuit, a driving method thereof, and a display device, so as to improve the display effect.

Therefore, an embodiment of the present invention provides a pixel circuit, the pixel circuit includes: a driving transistor, a data writing module, a light-emitting control module, a threshold compensation module, and a light-emitting device;

the data writing module is configured to provide the signal of the data signal terminal to the second pole of the driving transistor in response to the signal of the scan signal terminal;

The threshold compensation module is configured to reset the gate of the driving transistor and compensate the threshold voltage of the driving transistor in response to the signal at the reset signal terminal;

The light-emitting control module is configured to, in response to the signal of the light-emitting control terminal, provide the signal of the first voltage terminal to the first electrode of the driving transistor, and conduct the second electrode of the driving transistor with the light-emitting device;

The driving transistor is configured to generate a driving current according to the gate voltage and the second electrode voltage of the driving transistor, so as to drive the light emitting device to emit light through the driving current.

Optionally, in this embodiment of the present invention, the threshold compensation module includes a first submodule, a second submodule, and a third submodule;

the first sub-module is configured to store the voltage of the gate of the drive transistor and the second pole of the drive transistor;

the second sub-module is configured to turn on the first electrode of the driving transistor and the gate of the driving transistor in response to the signal of the reset signal terminal;

The third sub-module is configured to store the voltage of the first voltage terminal and the gate of the driving transistor.

Optionally, in this embodiment of the present invention, the first sub-module includes a first capacitor, the first end of the first capacitor is coupled to the second pole of the driving transistor, and the first end of the first capacitor is coupled to the second pole of the driving transistor. The two terminals are coupled to the gate of the drive transistor; and/or,

The third sub-module includes: a second capacitor, one end of the second capacitor is coupled to the first voltage end, and a second end of the second capacitor is coupled to the gate of the driving transistor.

Optionally, in this embodiment of the present invention, the threshold compensation module further includes a fourth sub-module, wherein the gate of the driving transistor is coupled to the second terminal of the second capacitor through the fourth sub-module catch;

The fourth sub-module is configured to turn on the gate of the driving transistor and the second terminal of the second capacitor in response to the signal at the scan signal terminal.

Optionally, in this embodiment of the present invention, the fourth sub-module includes a fifth transistor, the gate of the fifth transistor is coupled to the scan signal terminal, and the first pole of the fifth transistor is connected to the The second terminal of the second capacitor is coupled, and the second electrode of the fifth transistor is coupled to the gate of the driving transistor.

Optionally, in this embodiment of the present invention, the second sub-module includes a first transistor, the gate of the first transistor is coupled to the reset signal terminal, and the first pole of the first transistor is connected to the reset signal terminal. The first electrode of the driving transistor is coupled, and the second electrode of the first transistor is coupled to the gate of the driving transistor.

Optionally, in this embodiment of the present invention, the data writing module includes a second transistor, the gate of the second transistor is coupled to the scan signal terminal, and the first electrode of the second transistor is connected to the scan signal terminal. The data signal terminal is coupled, and the second electrode of the second transistor is coupled to the second electrode of the driving transistor.

Optionally, in this embodiment of the present invention, the lighting control module includes a third transistor and a fourth transistor;

The gate of the third transistor is coupled to the light-emitting control terminal, the first electrode of the third transistor is coupled to the second electrode of the driving transistor, and the second electrode of the third transistor is coupled to the the first pole of the light emitting device is coupled;

The gate of the fourth transistor is coupled to the light-emitting control terminal, the first electrode of the fourth transistor is coupled to the first voltage terminal, and the second electrode of the fourth transistor is coupled to the driving transistor The first pole is coupled.

Correspondingly, an embodiment of the present invention further provides a display device provided by an embodiment of the present invention, wherein the pixel circuit of the display device is described above.

Correspondingly, an embodiment of the present invention also provides a method for driving the above-mentioned pixel circuit provided by an embodiment of the present invention, including:

In the initialization stage, the data writing module provides the signal of the data signal terminal to the second pole of the driving transistor in response to the signal of the scan signal terminal; the threshold compensation module responds to the signal of the reset signal terminal, reset the gate of the driving transistor; the light-emitting control module, in response to the signal of the light-emitting control terminal, provides the signal of the first voltage terminal to the first pole of the driving transistor, and the driving transistor The second pole of is conductive with the light emitting device;

In the threshold compensation stage, the data writing module provides the signal of the data signal terminal to the second pole of the driving transistor in response to the signal of the scanning signal terminal; the threshold value compensation module of the threshold voltage of the driving transistor make compensation;

In the data writing stage, the data writing module provides the signal of the data signal terminal to the second pole of the driving transistor in response to the signal of the scan signal terminal;

In the light-emitting stage, the light-emitting control module responds to the signal of the light-emitting control terminal, provides the signal of the first voltage terminal to the first pole of the driving transistor, and connects the second pole of the driving transistor with the light-emitting The device is turned on; the driving transistor generates a driving current according to the gate voltage and the second electrode voltage of the driving transistor, so as to drive the light-emitting device to emit light through the driving current.

The beneficial effects of the present invention are as follows:

The pixel circuit, the driving method thereof, and the display device provided by the embodiments of the present invention include a driving transistor, a data writing module, a light-emitting control module, a threshold compensation module, and a light-emitting device; the data writing module is configured to respond to the signal of the scanning signal terminal, The signal of the data signal terminal is provided to the second pole of the driving transistor; the threshold value compensation module is configured to reset the gate of the driving transistor and compensate the threshold voltage of the driving transistor in response to the signal of the reset signal terminal; is configured to provide the signal of the first voltage terminal to the first electrode of the driving transistor in response to the signal of the light-emitting control terminal, and conduct the second electrode of the driving transistor with the light-emitting device; the driving transistor is configured to be based on the gate voltage of the driving transistor and the second electrode voltage to generate a driving current to drive the light emitting device to emit light through the driving current. Therefore, in the pixel circuit provided by the embodiment of the present invention, the threshold voltage of the driving transistor can be compensated by the cooperation of the above-mentioned modules and components, so that the driving current for driving the light-emitting device to emit light is not affected by the threshold voltage of the driving module, and the threshold voltage due to the threshold voltage is improved. The problem of uneven luminous brightness caused by uneven voltage. In addition, through the cooperation of the above-mentioned modules and components, the voltage of the first voltage terminal can be compensated, so that the driving current is not affected by the voltage of the first voltage terminal, and the problem of uneven luminous brightness caused by the IR Drop of the first voltage terminal can be improved. .

Description of drawings

FIG. 1 is a schematic structural diagram of a pixel circuit provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of another pixel circuit provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another pixel circuit provided by an embodiment of the present invention;

FIG. 4 is a signal timing diagram of the pixel circuit shown in FIG. 3;

FIG. 5 is a schematic structural diagram of another pixel circuit provided by an embodiment of the present invention;

6 is a signal timing diagram of the pixel circuit shown in FIG. 5;

7 is a flowchart of a method for driving a pixel circuit according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a display device according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the specific implementations of the pixel circuit, its driving method and the display device provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the preferred embodiments described below are only used to illustrate and explain the present invention, but not to limit the present invention. Also, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.

An embodiment of the present invention provides a pixel circuit, as shown in FIG. 1 , including a driving transistor M0, a data writing module 101, a light-emitting control module 102, a threshold compensation module 103 and a light-emitting device 104; the data writing module 101 is configured as In response to the signal of the scanning signal terminal Gate, the signal of the data signal terminal Data is provided to the second pole of the driving transistor; the threshold compensation module 103 is configured to respond to the signal of the reset signal terminal Reset, reset the gate of the driving transistor M0 , and compensate the threshold voltage of the driving transistor M0; the light-emitting control module 102 is configured to provide the signal of the first voltage terminal VDD to the first pole of the driving transistor M0 in response to the signal of the light-emitting control terminal EM, and the driving transistor M0 The second pole of M0 is turned on with the light emitting device 104; the driving transistor M0 is configured to generate a driving current according to the gate voltage and the second pole voltage of the driving transistor M0, so as to drive the light emitting device 104 to emit light through the driving current.

The pixel circuit provided by the embodiment of the present invention includes a driving transistor, a data writing module, a light-emitting control module, a threshold compensation module, and a light-emitting device; the data writing module is configured to respond to the signal of the scanning signal terminal, and provide the signal of the data signal terminal to the the second pole of the driving transistor; the threshold compensation module is configured to reset the gate of the driving transistor and compensate the threshold voltage of the driving transistor in response to the signal of the reset signal terminal; the lighting control module is configured to respond to the signal of the lighting control terminal signal, the signal of the first voltage terminal is provided to the first pole of the driving transistor, and the second pole of the driving transistor is turned on with the light emitting device; the driving transistor is configured to generate a driving transistor according to the gate voltage and the second pole voltage of the driving transistor current to drive the light-emitting device to emit light through the driving current. Therefore, in the pixel circuit provided by the embodiment of the present invention, the threshold voltage of the driving transistor can be compensated by the cooperation of the above-mentioned modules and components, so that the driving current for driving the light-emitting device to emit light is not affected by the threshold voltage of the driving module, and the threshold voltage due to the threshold voltage is improved. The problem of uneven luminous brightness caused by uneven voltage. In addition, through the cooperation of the above modules and components, the voltage of the first voltage terminal can be compensated, so that the driving current is not affected by the voltage of the first voltage terminal, and the problem of uneven brightness caused by the IRDrop of the first voltage terminal can be improved.

The present invention will be described in detail below with reference to specific embodiments. It should be noted that this embodiment is for better explanation of the present invention, but does not limit the present invention.

Embodiment 1.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the threshold compensation module 103 includes a first sub-module 1031 , a second sub-module 1032 and a third sub-module 1033 ; the first sub-module 1031 The second sub-module 1032 is configured to store the voltage of the gate G of the driving transistor M0 and the second pole D of the driving transistor M0; The gate G of the transistor is turned on; the third sub-module 1033 is configured to store the voltage of the first voltage terminal VDD and the gate G of the driving transistor M0.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 3 , the first sub-module 1031 includes a first capacitor C1, the first end of the first capacitor C1 and the second electrode D of the driving transistor M0 The second end of the first capacitor C1 is coupled to the gate G of the driving transistor M0.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 3 , the second sub-module 1032 includes a first transistor M1, the gate of the first transistor M1 is coupled to the reset signal terminal Reset, and the first transistor M1 The first electrode of the transistor M1 is coupled to the first electrode S of the driving transistor M0, and the second electrode of the first transistor M1 is coupled to the gate G of the driving transistor M0.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 3 , the third sub-module 1033 includes: a second capacitor C2, one end of the second capacitor C2 is coupled to the first voltage terminal VDD, and the first The second terminal of the two capacitors C2 is coupled to the gate G of the driving transistor M0.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 3 , the data writing module 101 includes a second transistor M2, the gate of the second transistor M2 is coupled to the scanning signal terminal Gate, and the second transistor M2 The first electrode of the transistor M2 is coupled to the data signal terminal Data, and the second electrode of the second transistor M2 is coupled to the second electrode D of the driving transistor M0.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 3 , the light-emitting control module 102 includes a third transistor M3 and a fourth transistor M4; the gate of the third transistor M3 is coupled to the light-emitting control terminal EM connected, the first pole of the third transistor M3 is coupled to the second pole D of the driving transistor M0, the second pole of the third transistor M3 is coupled to the first pole of the light emitting device 104; the gate of the fourth transistor M4 is connected to the light emitting device 104. The control EM terminal is coupled, the first pole of the fourth transistor M4 is coupled to the first voltage terminal VDD, and the second pole of the fourth transistor M4 is coupled to the first pole S of the driving transistor M0.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the first end of the light emitting device 104 is coupled to the light emitting control module 102 , and the second end of the light emitting device 104 is connected to the second voltage end VSS coupled. Moreover, in a specific implementation, the light-emitting device 104 may be at least one of an organic light-emitting diode (Organic Light Emitting Diode, OLED) and a quantum dot light-emitting diode (Quantum Dot Light Emitting Diodes, QLED). For example, when the light-emitting device 104 is an OLED, the positive electrode of the OLED is the first end of the light-emitting device 104 , and the negative electrode is the second end of the light-emitting device 104 .

Generally, when the voltage difference across the light-emitting device is greater than the turn-on voltage value of the turn-on voltage, the light-emitting device can emit light. In specific implementation, in the pixel circuit provided by the embodiment of the present invention, as shown in FIG. 3 , the voltage value Vdata of the data signal terminal Data, the voltage value Vss of the second voltage terminal VSS, and the turn-on voltage value Voled of the light emitting device 104 satisfy Relational formula: 2Voled+Vss>Vdata>Voled+Vss.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, the above transistors are all shown by taking P-type transistors as an example. For the case where the above-mentioned transistors are N-type transistors, the design principle is the same as that of the present invention, which also belongs to the present invention. Scope of invention protection.

The above is only an example to illustrate the specific structure of each circuit in the pixel circuit provided by the embodiment of the present invention. During specific implementation, the specific structure of each of the above circuits is not limited to the above-mentioned structure provided by the embodiment of the present invention, and may also be known to those skilled in the art. Other structures are not limited here.

Specifically, in the pixel circuit provided by the embodiment of the present invention, the above-mentioned transistors may be thin film transistors (TFT, Thin Film Transistor) or metal oxide semiconductor field effect transistors (MOS, Metal Oxide Scmiconductor), which is not limited here. . And according to the type of each transistor and the signal of the gate of each transistor, the first electrode of the transistor can be used as the source electrode and the second electrode as the drain electrode, or the first electrode of the transistor can be used as the drain electrode and the second electrode as the drain electrode. The pole is used as the source, and no specific distinction is made here.

The working process of the pixel circuit provided by the embodiment of the present invention is described below with reference to the circuit timing diagram. In the following description, 1 means high level and 0 means low level. It should be noted that, 1 and 0 are logic levels, which are only to better explain the specific working process of the embodiment of the present invention, rather than specific voltage values.

Taking the pixel circuit shown in FIG. 3 as an example, the timing diagram corresponding to the input signal is shown in FIG. 4 . The signal timing diagram shown in FIG. 4 includes an initialization phase T1, a threshold compensation phase T2, a data writing phase T3, and a light-emitting phase T4. The voltage of the signal at the first voltage terminal VDD is Vdd, and the voltage of the signal at the second voltage terminal VSS is Vss.

In the initialization phase T1, EM=1, Gate=1, Reset=1;

Since Gate=1, the second transistor M2 is turned on, and the voltage Vref of the signal of the data signal terminal Data is supplied to the second electrode D of the driving transistor M0. Since EM=1, the third transistor M3 and the fourth transistor M4 are turned on, and the turned-on fourth transistor M4 provides the signal of the first voltage terminal VDD to the first pole S of the driving transistor M0, and the first pole of the driving transistor M0 The voltage of S is Vdd. The turned-on third transistor M3 provides the signal of the second electrode D of the driving transistor M0 to the first electrode of the light emitting device 104, and the first electrode of the light emitting device 104 is initialized. Since Reset=1, the first transistor M1 is turned on, the voltage Vdd of the first electrode S of the driving transistor M0 is supplied to the gate G of the driving transistor M0, and the voltage of the signal of the gate G of the driving transistor M0 is Vdd. The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second electrode D of the driving transistor M0; the second capacitor C2 stores the voltage of the first voltage terminal VDD and the gate G of the driving transistor M0.

Threshold compensation stage T2, EM=0, Gate=1, Reset=1;

Since EM=0, the third transistor M3 and the fourth transistor M4 are turned off. Since Gate=1, the second transistor M2 is turned on, and the voltage Vdata of the signal of the data signal terminal Data is provided to the second electrode D of the driving transistor M0, and the voltage of the second electrode D of the driving transistor M0 changes from Vref to Vdata. Since Reset=1, the first transistor M1 is turned on, the first electrode S and the gate G of the driving transistor M0 are turned on, so that the driving transistor M0 forms a diode structure, the gate voltage of the driving transistor M0 is discharged, and the gate of the driving transistor M0 is discharged. When the voltage changes to Vdata+Vth, the driving transistor M0 is turned off. Wherein Vth is the threshold voltage of the driving transistor M0. The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second electrode D of the driving transistor M0, and the second capacitor C2 stores the voltage of the first voltage terminal VDD and the gate G of the driving transistor M0.

Data writing stage T3, EM=0, Gate=1, Reset=0;

第一电容C1存储驱动晶体管M0的栅极G与驱动晶体管M0第二极D的电压，第二电容C2存储第一电压端VDD与驱动晶体管M0的栅极G的电压。Since EM=0, the third transistor M3 and the fourth transistor M4 are turned off. Since Reset=0, the first transistor M1 is turned off. Since Gate=1, the second transistor M2 is turned on, and the voltage Vref of the signal at the data signal terminal Data is provided to the second pole D of the driving transistor M0, and the voltage of the second pole D of the driving transistor M0 changes from Vdata to Vref, then The signal of the gate G of the drive transistor M0 changes from Vdata+Vth to

The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second electrode D of the driving transistor M0, and the second capacitor C2 stores the voltage of the first voltage terminal VDD and the gate G of the driving transistor M0.

Light-emitting stage T4, EM=1, EM=0, Gate=0, Reset=0;

Since Reset=0, the first transistor M1 is turned off. Since Gate=0, the second transistor M2 is turned off. Since EM=1, the third transistor M3 and the fourth transistor M4 are turned on. The voltage of the second electrode D of the driving transistor M0 changes from Vref to Voled+Vss. The turned-on fourth transistor M4 provides the signal of the first voltage terminal VDD to the first pole S of the driving transistor M0, and the turned-on third transistor M3 turns on the second pole D of the driving transistor M0 and the light emitting device 104. The voltage value V _G of the signal of the gate G of the driving transistor M0 changes as:

Therefore, the voltage difference V _GD between the gate G and the second electrode D of the driving transistor M0 can be obtained as:

The driving current I of the driving transistor M0 for driving the light-emitting device to emit light is:

其中，

μ_n代表驱动晶体管DT的迁移率，C_ox为单位面积栅氧化层电容，

为驱动晶体管DT的宽长比，相同结构中这些数值相对稳定，可以算作常量。

in,

μ _n represents the mobility of the driving transistor DT, C _ox is the gate oxide capacitance per unit area,

For the aspect ratio of the driving transistor DT, these values are relatively stable in the same structure and can be regarded as constants.

It can be known from the above formula that the driving current I output by the driving transistor M0 is not affected by the threshold voltage Vth of the driving transistor M0 and the voltage drop of the first voltage source VDD, thus improving the driving transistor M0 due to the process and The long-term operation causes problems of threshold voltage drift and voltage drop of the first voltage source VDD, thereby improving the display effect.

Furthermore, it can be known from the above formula that the data signal terminal Data only needs to provide an appropriate voltage Vdata, that is, the driving current I can be not affected by the turn-on voltage value Voled of the light emitting device 104 . Furthermore, when the light-emitting device 104 ages and changes its turn-on voltage value, the voltage Vdata of the data voltage terminal Data can be adjusted so that the driving current of the driving transistor M0 to drive the light-emitting device 104 to emit light is not affected by the aging degree of the light-emitting device.

Embodiment two,

A schematic structural diagram of a pixel circuit corresponding to an embodiment of the present invention is shown in FIG. 5 , which is modified from the implementation in the first embodiment. Only the differences between this embodiment and the first embodiment will be described below, and the similarities will not be repeated here.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, the threshold compensation module 103 further includes a fourth sub-module, wherein the gate of the driving transistor is coupled to the second end of the second capacitor through the fourth sub-module; The fourth sub-module is configured to conduct the gate of the driving transistor with the second terminal of the second capacitor in response to the signal of the scanning signal terminal.

During specific implementation, in the pixel circuit provided by the embodiment of the present invention, the fourth sub-module includes a fifth transistor M5, the gate of the fifth transistor M5 is coupled to the scanning signal terminal Gate, and the first pole of the fifth transistor M5 is connected to the scanning signal terminal Gate. The second terminal of the second capacitor C2 is coupled, and the second electrode of the fifth transistor M5 is coupled to the gate of the driving transistor M0.

The working process of the pixel circuit provided by the embodiment of the present invention is described below with reference to the circuit timing diagram. In the following description, 1 means high level and 0 means low level. It should be noted that, 1 and 0 are logic levels, which are only to better explain the specific working process of the embodiment of the present invention, rather than specific voltage values.

Taking the pixel circuit shown in FIG. 5 as an example, the timing diagram corresponding to the input signal is shown in FIG. 6 . The signal timing diagram shown in FIG. 6 includes an initialization phase T1, a threshold compensation phase T2, a data writing phase T3, a buffer phase T3', and a light-emitting phase T4. The voltage of the signal at the first voltage terminal VDD is Vdd, and the voltage of the signal at the second voltage terminal VSS is Vss.

In the initialization phase T1, EM=1, Gate=1, Reset=1;

Since Gate=1, the second transistor M2 and the fifth transistor M5 are turned on. The turned-on second transistor M2 supplies the voltage Vref of the signal of the data signal terminal Data to the second electrode D of the driving transistor M0. The fifth transistor M5 conducts the second end of the second capacitor C2 with the gate of the driving transistor M0. Since EM=1, the third transistor M3 and the fourth transistor M4 are turned on, and the turned-on fourth transistor M4 provides the signal of the first voltage terminal VDD to the first pole S of the driving transistor M0, and the first pole of the driving transistor M0 The voltage of S is Vdd. The turned-on third transistor M3 provides the signal of the second electrode D of the driving transistor M0 to the first electrode of the light emitting device 104, and the first electrode of the light emitting device 104 is initialized. Since Reset=1, the first transistor M1 is turned on, the voltage Vdd of the first electrode S of the driving transistor M0 is supplied to the gate G of the driving transistor M0, and the voltage of the signal of the gate G of the driving transistor M0 is Vdd. The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second electrode D of the driving transistor M0; the second capacitor C2 stores the voltage of the first voltage terminal VDD and the gate G of the driving transistor M0.

Threshold compensation stage T2, EM=0, Gate=1, Reset=1;

Since EM=0, the third transistor M3 and the fourth transistor M4 are turned off. Since Gate=1, the second transistor M2 and the fifth transistor M5 are turned on, and the turned-on second transistor M2 provides the voltage Vref of the signal of the data signal terminal Data to the second electrode D of the driving transistor M0. The turned-on fifth transistor M5 turns on the second end of the second capacitor C2 and the gate G of the driving transistor M0. Since Reset=1, the first transistor M1 is turned on, the first electrode S and the gate G of the driving transistor M0 are turned on, so that the driving transistor M0 forms a diode structure, the gate voltage of the driving transistor M0 is discharged, and the gate of the driving transistor M0 is discharged. When the voltage changes from Vdd to Vref+Vth, the driving transistor M0 is turned off, and Vdd-Vref>Vth. Wherein Vth is the threshold voltage of the driving transistor M0. The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second electrode D of the driving transistor M0, and the second capacitor C2 stores the voltage of the first voltage terminal VDD and the gate G of the driving transistor M0.

Data writing stage T3, EM=0, Gate=1, Reset=0;

第一电容C1存储驱动晶体管M0的栅极G与驱动晶体管M0第二极D的电压，第二电容C2存储第一电压端VDD与驱动晶体管M0的栅极G的电压。由于要确保V_GD>Vth，因此需要保证V_G-V_D>Vth，从而可以使

最终使得Vref>Vdata。其中，V_G代表驱动晶体管M0栅极G的信号的电压值，V_D代表驱动晶体管M0第二极D的信号的电压值。Since EM=0, the third transistor M3 and the fourth transistor M4 are turned off. Since Reset=0, the first transistor M1 is turned off. Since Gate=1, the second transistor M2 and the fifth transistor M5 are turned on, and the voltage Vdata of the signal of the data signal terminal Data is provided to the second pole D of the driving transistor M0, and the voltage of the second pole D of the driving transistor M0 is determined by Vref becomes Vdata, then the signal of the gate G of the drive transistor M0 changes from Vref+Vth to

The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second electrode D of the driving transistor M0, and the second capacitor C2 stores the voltage of the first voltage terminal VDD and the gate G of the driving transistor M0. Since it is necessary to ensure that V _GD >Vth, it is necessary to ensure that V _G -V _D >Vth, so that the

Finally make Vref>Vdata. Wherein, V _G represents the voltage value of the signal of the gate G of the driving transistor M0, and V _D represents the voltage value of the signal of the second pole D of the driving transistor M0.

Buffer stage T3', EM=0, Gate=0, Reset=0;

第一电容C1存储驱动晶体管M0的栅极G与驱动晶体管M0第二极D的电压，第二电容C2存储第一电压端VDD与第五晶体管M5的第一极的电压。Since EM=0, the third transistor M3 and the fourth transistor M4 are turned off. Since Gate=0, the second transistor M2 and the fifth transistor M5 are turned off. Since Reset=0, the first transistor M1 is turned off. At this time, the voltage across the first capacitor C1 is the same as the voltage of the gate G and the second electrode D of the driving transistor M0 in the data writing stage T3, that is,

The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second electrode D of the driving transistor M0, and the second capacitor C2 stores the voltage of the first voltage terminal VDD and the first electrode of the fifth transistor M5.

Light-emitting stage T4, EM=1, EM=0, Gate=0, Reset=0;

Since Reset=0, the first transistor M1 is turned off. Since Gate=0, the second transistor M2 and the fifth transistor M5 are turned off. Since EM=1, the third transistor M3 and the fourth transistor M4 are turned on. The voltage of the second electrode D of the driving transistor M0 changes from Vdata to Voled+Vss. The turned-on fourth transistor M4 provides the signal of the first voltage terminal VDD to the first pole S of the driving transistor M0, and the turned-on third transistor M3 turns on the second pole D of the driving transistor M0 and the light emitting device 104. The voltage difference V _GD between the gate G and the second pole D of the driving transistor M0 is:

The driving current I of the driving transistor M0 for driving the light-emitting device to emit light is:

其中，

μ_n代表驱动晶体管DT的迁移率，C_ox为单位面积栅氧化层电容，

为驱动晶体管DT的宽长比，相同结构中这些数值相对稳定，可以算作常量。

in,

μ _n represents the mobility of the driving transistor DT, C _ox is the gate oxide capacitance per unit area,

For the aspect ratio of the driving transistor DT, these values are relatively stable in the same structure and can be regarded as constants.

It can be known from the above formula that the driving current I output by the driving transistor M0 is not affected by the threshold voltage Vth of the driving transistor M0 and the voltage drop of the first voltage source VDD, thus improving the driving transistor M0 due to the process and The long-term operation causes problems of threshold voltage drift and voltage drop of the first voltage source VDD, thereby improving the display effect.

Based on the same inventive concept, an embodiment of the present invention also provides a method for driving a pixel circuit provided by an embodiment of the present invention. As shown in FIG. 7 , the method includes steps 701 to 704;

Step 701, in the initialization stage, the data writing module responds to the signal of the scanning signal terminal, and provides the signal of the data signal terminal to the second pole of the driving transistor; the threshold compensation module responds to the signal of the reset signal terminal, and resets the gate of the driving transistor; In response to the signal of the light-emitting control terminal, the light-emitting control module provides the signal of the first voltage terminal to the first pole of the driving transistor, and conducts the second pole of the driving transistor with the light-emitting device;

Step 702, in the threshold compensation stage, the data writing module responds to the signal at the scanning signal terminal, and provides the signal at the data signal terminal to the second pole of the driving transistor; the threshold compensation module compensates the threshold voltage of the driving transistor;

Step 703, the data writing stage, the data writing module provides the signal of the data signal terminal to the second pole of the driving transistor in response to the signal of the scanning signal terminal;

Step 704, in the light-emitting stage, the light-emitting control module responds to the signal of the light-emitting control terminal, provides the signal of the first voltage terminal to the first pole of the driving transistor, and conducts the second pole of the driving transistor with the light-emitting device; The gate voltage and the second electrode voltage generate a driving current, so as to drive the light emitting device to emit light through the driving current.

Based on the same inventive concept, an embodiment of the present invention further provides a display device, including the above-mentioned pixel circuit provided by the embodiment of the present invention. For the implementation of the display device, reference may be made to the above-mentioned embodiments of the pixel circuit, and repeated descriptions will not be repeated.

During specific implementation, the above-mentioned display device provided by the embodiment of the present invention may be a mobile phone with a full screen as shown in FIG. 8 . Of course, the above-mentioned display device provided in the embodiment of the present invention may also be any product or component with display function, such as a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital photo frame, and a navigator. Other essential components of the display device should be understood by those of ordinary skill in the art, and will not be repeated here, nor should it be regarded as a limitation of the present invention.

The pixel circuit, the driving method thereof, and the display device provided by the embodiments of the present invention include a driving transistor, a data writing module, a light-emitting control module, a threshold compensation module, and a light-emitting device; the data writing module is configured to respond to the signal of the scanning signal terminal, The signal of the data signal terminal is provided to the second pole of the driving transistor; the threshold value compensation module is configured to reset the gate of the driving transistor and compensate the threshold voltage of the driving transistor in response to the signal of the reset signal terminal; is configured to provide the signal of the first voltage terminal to the first electrode of the driving transistor in response to the signal of the light-emitting control terminal, and conduct the second electrode of the driving transistor with the light-emitting device; the driving transistor is configured to be based on the gate voltage of the driving transistor and the second electrode voltage to generate a driving current to drive the light emitting device to emit light through the driving current. Therefore, in the pixel circuit provided by the embodiment of the present invention, the threshold voltage of the driving transistor can be compensated by the cooperation of the above-mentioned modules and components, so that the driving current for driving the light-emitting device to emit light is not affected by the threshold voltage of the driving module, and the threshold voltage due to the threshold voltage is improved. The problem of uneven luminous brightness caused by uneven voltage. In addition, through the cooperation of the above-mentioned modules and components, the voltage of the first voltage terminal can be compensated, so that the driving current is not affected by the voltage of the first voltage terminal, and the problem of uneven luminous brightness caused by the IR Drop of the first voltage terminal can be improved. .

Claims (5)

1. A pixel circuit is characterized by comprising a driving transistor, a data writing module, a light emitting control module, a threshold compensation module and a light emitting device;

the data writing module is configured to provide a signal of a data signal terminal to the second pole of the driving transistor in response to a signal of a scan signal terminal;

the threshold compensation module is configured to reset the gate of the driving transistor and compensate for a threshold voltage of the driving transistor in response to a signal of a reset signal terminal;

the light emitting control module is configured to provide a signal of a first voltage terminal to a first pole of the driving transistor and to conduct a second pole of the driving transistor with the light emitting device in response to a signal of a light emitting control terminal;

the driving transistor is configured to generate a driving current according to a gate voltage and a second pole voltage of the driving transistor to drive the light emitting device to emit light by the driving current;

the threshold compensation module comprises a first sub-module, a second sub-module, a third sub-module and a fourth sub-module; the first sub-module is configured to store a voltage of a gate of the driving transistor and a second pole of the driving transistor; the second sub-module is configured to conduct the first pole of the driving transistor and the gate of the driving transistor in response to a signal of the reset signal terminal; the third sub-module is configured to store a voltage of the first voltage terminal and a gate of the driving transistor;

the first sub-module comprises a first capacitor, wherein a first end of the first capacitor is coupled with the second pole of the driving transistor, and a second end of the first capacitor is coupled with the grid electrode of the driving transistor;

the second sub-module comprises a first transistor, a grid electrode of the first transistor is coupled with the reset signal end, a first pole of the first transistor is coupled with a first pole of the driving transistor, and a second pole of the first transistor is coupled with the grid electrode of the driving transistor;

the third sub-module includes: a second capacitor, wherein one end of the second capacitor is coupled to the first voltage end, and a second end of the second capacitor is coupled to the gate of the driving transistor;

the grid electrode of the driving transistor is coupled with the second end of the second capacitor through the fourth submodule; the fourth sub-module is configured to conduct the gate of the driving transistor and the second end of the second capacitor in response to a signal of the scan signal end; the fourth sub-module comprises a fifth transistor, a gate of the fifth transistor is coupled to the scan signal terminal, a first pole of the fifth transistor is coupled to the second terminal of the second capacitor, and a second pole of the fifth transistor is coupled to the gate of the driving transistor;

the driving transistor is configured to initialize a grid electrode, a first pole and a second pole thereof in an initialization stage;

the fifth transistor is further configured to block the second terminal of the second capacitor from the gate of the driving transistor during a buffering phase and a light emitting phase.

2. The pixel circuit according to claim 1, wherein the data writing module comprises a second transistor, a gate of the second transistor is coupled to the scan signal terminal, a first pole of the second transistor is coupled to the data signal terminal, and a second pole of the second transistor is coupled to the second pole of the driving transistor.

3. The pixel circuit according to claim 1, wherein the light emission control module includes a third transistor and a fourth transistor;

a gate of the third transistor is coupled to the light emitting control terminal, a first pole of the third transistor is coupled to the second pole of the driving transistor, and the second pole of the third transistor is coupled to the first pole of the light emitting device;

a gate of the fourth transistor is coupled to the light emission control terminal, a first pole of the fourth transistor is coupled to the first voltage terminal, and a second pole of the fourth transistor is coupled to the first pole of the driving transistor.

4. A display device comprising the pixel circuit according to any one of claims 1 to 3.

5. A driving method using the pixel circuit according to any one of claims 1 to 3, comprising:

the data writing module responds to the signal of the scanning signal end and provides the signal of the data signal end to the second pole of the driving transistor in the initialization stage; the threshold compensation module responds to a signal of the reset signal end to reset the grid electrode of the driving transistor; the light-emitting control module responds to a signal of the light-emitting control terminal, provides a signal of the first voltage terminal to a first pole of the driving transistor, and conducts a second pole of the driving transistor and the light-emitting device;

a threshold compensation stage, wherein the data writing module responds to the signal of the scanning signal end and provides the signal of the data signal end to the second pole of the driving transistor; the threshold compensation module compensates the threshold voltage of the driving transistor;

a data writing stage, wherein the data writing module responds to the signal of the scanning signal end and provides the signal of the data signal end to the second pole of the driving transistor;

a light emitting stage, wherein the light emitting control module responds to a signal of the light emitting control terminal, provides a signal of the first voltage terminal to a first pole of the driving transistor, and conducts a second pole of the driving transistor with the light emitting device; the driving transistor generates a driving current according to a gate voltage and a second pole voltage of the driving transistor to drive the light emitting device to emit light by the driving current.

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