CN110544458A - Pixel circuit, driving method thereof and display device - Google Patents

Abstract

The invention discloses a pixel circuit, its driving method and a display device. The pixel circuit includes a driving transistor, a data writing module, a lighting control module, a threshold compensation module and a light emitting device; the data writing module provides the signal of the data signal terminal to The second pole of the drive transistor; the threshold compensation module resets the gate of the drive transistor and compensates the threshold voltage of the drive transistor; the light emission control module provides the signal of the first voltage terminal to the first pole of the drive transistor, and drives The second pole of the transistor is connected to the light-emitting device; the driving transistor is used to generate 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. Moreover, 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, its driving method and display device

technical field

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

Background technique

The organic light emitting diode (Organic Light Emitting Diode, OLED) panel has the characteristics of bendability, high contrast ratio, low power consumption, etc., and has 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 service time, the threshold voltage Vth of the driving transistor will drift to different degrees, so that the OLED panel will have the problem of uneven luminance of the OLED. 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.

Contents of the invention

Embodiments of the present invention provide a pixel circuit, a driving method thereof, and a display device for improving display effect.

Therefore, an embodiment of the present invention provides a pixel circuit, and the pixel circuit includes: a driving transistor, a data writing module, a light emission 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 drive transistor and compensate the threshold voltage of the drive transistor in response to a signal at the reset signal terminal;

The light emission control module 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 emission control terminal, 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 the 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 voltages of the gate of the driving transistor and the second pole of the driving transistor;

The second sub-module is configured to conduct the first electrode of the driving transistor with the gate of the driving transistor in response to the signal of the reset signal terminal;

The third sub-module is configured to store voltages 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 terminal of the first capacitor is coupled to the second pole of the driving transistor, and the first terminal of the first capacitor The two terminals are coupled to the gate of the driving transistor; and/or,

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

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

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.

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, the first electrode of the fifth transistor is connected to the The second end of the second capacitor is coupled, and the second pole 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 electrode of the first transistor is connected to the The first pole of the driving transistor is coupled, and the second pole of the first transistor is coupled to the gate of the driving transistor.

Optionally, in the 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, the first electrode of the second transistor is connected to the The data signal terminal is coupled, and the second pole of the second transistor is coupled with the second pole of the driving transistor.

Optionally, in the embodiment of the present invention, the light emission 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 pole of the third transistor is coupled to the second pole of the driving transistor, the second pole 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 pole of the fourth transistor is coupled to the first voltage terminal, and the second pole of the fourth transistor is coupled to the driving transistor. first pole coupling.

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

Correspondingly, the embodiment of the present invention also provides a driving method for the pixel circuit provided in the 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 scanning signal terminal; the threshold compensation module responds to the signal of the reset signal terminal, Reset the gate of the drive transistor; the light emission control module provides the signal of the first voltage terminal to the first pole of the drive transistor in response to the signal of the light emission control terminal, and the drive transistor The second pole of the light-emitting device is turned on;

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 compensation module controls 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 scanning signal terminal;

In the light-emitting stage, the light-emitting control module provides the signal of the first voltage terminal to the first pole of the driving transistor in response to the signal of the light-emitting control terminal, and connects the second pole of the driving transistor to 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 provided by the embodiments of the present invention, its driving method, and display device include a driving transistor, a data writing module, a light emission 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 at the data signal terminal is provided to the second pole of the drive transistor; the threshold compensation module is configured to reset the gate of the drive transistor and compensate the threshold voltage of the drive transistor in response to the signal at the reset signal terminal; the light emission control module is It is configured to respond to the signal of the light-emitting control terminal, provide the signal of the first voltage terminal to the first pole of the driving transistor, and conduct the second pole of the driving transistor with the light-emitting device; the driving transistor is configured according to the gate voltage of the driving transistor and the second pole voltage to generate a driving current, so as to drive the light emitting device to emit light through the driving current. Therefore, the pixel circuit provided by the embodiment of the present invention can compensate the threshold voltage of the driving transistor through the mutual 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. Moreover, through the mutual 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;

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

FIG. 7 is a flowchart of a driving method for a pixel circuit provided by an embodiment of the present invention;

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

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the pixel circuit provided by the embodiment of the present invention, its driving method and the specific implementation of the display device 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, not to limit the present invention. And in the case of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

An embodiment of the present invention provides a pixel circuit, as shown in FIG. 1 , including a drive transistor M0, a data writing module 101, a light emission 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 reset the gate of the driving transistor M0 in response to the signal of the reset signal terminal Reset , and compensate the threshold voltage of the drive transistor M0; the light emission control module 102 is configured to respond to the signal of the light emission control terminal EM, provide the signal of the first voltage terminal VDD to the first pole of the drive transistor M0, and the drive transistor M0 The second pole of M0 is connected to 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 emission 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 signal of the scanning signal terminal in response to the signal of the scanning signal terminal The second pole of the drive transistor; the threshold compensation module is configured to reset the gate of the drive transistor and compensate the threshold voltage of the drive transistor in response to the signal at the reset signal terminal; the light emission control module is configured to respond to the signal at the light emission 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 connected to the light emitting device; the driving transistor is configured to generate a driving voltage according to the gate voltage and the second pole voltage of the driving transistor The current is used to drive the light-emitting device to emit light through the driving current. Therefore, the pixel circuit provided by the embodiment of the present invention can compensate the threshold voltage of the driving transistor through the mutual 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. Moreover, through the mutual 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 IRDrop of the first voltage terminal can be improved.

The present invention will be described in detail below in conjunction with specific embodiments. It should be noted that this embodiment is for better explaining the present invention, but not limiting the present invention.

Embodiment one,

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 submodule 1031, a second submodule 1032 and a third submodule 1033; It is configured to store the voltage of the gate G of the driving crystal M0 and the second pole D of the driving transistor M0; the second sub-module 1032 is configured to respond to the signal of the reset signal terminal Reset, and connect the first pole S and 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. coupling, the second end of the first capacitor C1 is coupled to the gate G of the driving transistor M0.

In a 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 The first pole of the transistor M1 is coupled to the first pole S of the driving transistor M0 , and the second pole 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 second capacitor C2 is coupled to the first voltage terminal VDD. The second terminal of the second capacitor 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. The first pole of the transistor M2 is coupled to the data signal terminal Data, and the second pole of the second transistor M2 is coupled to the second pole 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 emission 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 emission control terminal EM connected, the first pole of the third transistor M3 is coupled to the second pole D of the drive 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 coupled to the light emitting 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. coupling. Moreover, in a specific implementation, the light emitting device 104 may be at least one of: organic light emitting diodes (Organic Light Emitting Diode, OLED) and quantum dot light emitting diodes (Quantum Dot Light Emitting Diodes, QLED). For example, when the light emitting device 104 is an OLED, the anode of the OLED is the first end of the light emitting device 104 , and the cathode is the second end of the light emitting device 104 .

Generally, the light emitting device can emit light when the voltage difference between the two ends of the light emitting device is greater than the turn-on voltage value of its turn-on voltage. During 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.

In specific implementation, in the pixel circuit provided by the embodiment of the present invention, the above-mentioned transistors are all shown as P-type transistors. For the case where the above-mentioned transistors are N-type transistors, the design principle is the same as that of the present invention, and also belongs to this invention. scope of invention protection.

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

Specifically, in the pixel circuit provided by the embodiment of the present invention, each of the above-mentioned transistors may be a thin film transistor (TFT, Thin Film Transistor), or a metal oxide semiconductor field effect transistor (MOS, Metal OxideSmiconductor), which is not limited herein. . And according to the difference of the type of the above-mentioned transistors and the signal of the gate of each transistor, the first pole of the above-mentioned transistor can be used as the source, and the second pole can be used as the drain, or the first pole of the transistor can be used as the drain, and the second pole can be used as the drain. 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 will be described below in conjunction with the circuit timing diagram. In the following description, 1 represents high level and 0 represents low level. It should be noted that 1 and 0 are logic levels, which are only used 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 lighting phase T4 . Wherein, 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 at the data signal terminal Data is provided to the second pole 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 S of the driving transistor M0 The voltage of S is Vdd. The turned-on third transistor M3 provides the signal of the second pole D of the driving transistor M0 to the first pole of the light emitting device 104, and the first pole of the light emitting device 104 is initialized. Since Reset=1, the first transistor M1 is turned on, and the voltage Vdd of the first pole S of the driving transistor M0 is provided 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 voltages 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 voltages 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 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 Vref to Vdata. Since Reset=1, the first transistor M1 is turned on, the first pole S of the driving transistor M0 is turned on with the gate G, so that the driving transistor M0 forms a diode structure, the gate voltage of the driving transistor M0 is discharged, and the gate voltage of the driving transistor M0 When the voltage changes to Vdata+Vth, the driving transistor M0 is turned off. Where 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 terminal 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;

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 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 changes from Vdata to Vref, then The signal driving the gate G of the 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 terminal 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 .

Lighting 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 pole 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 driving the gate G of the transistor M0 changes as:

Therefore, it can be obtained that the voltage difference V _GD between the gate G of the driving transistor M0 and the second pole D is:

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

in, μ _n represents the mobility of the driving transistor DT, C _ox is the capacitance of the gate oxide layer per unit area, For the width-to-length 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 no longer affected by the threshold voltage Vth of the driving transistor M0 and the voltage drop of the first voltage source VDD, thus improving the performance of the driving transistor M0 due to the process and The long time operation causes the threshold voltage drift and the voltage drop of the first voltage source VDD, thereby improving the display effect.

Moreover, it can be known from the above formula that the data signal terminal Data only needs to provide an appropriate voltage Vdata, so that the driving current I is not affected by the turn-on voltage Voled of the light emitting device 104 . Furthermore, when the light-emitting device 104 ages, causing its turn-on voltage to change, the voltage Vdata at 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 the embodiment of the present invention is shown in FIG. 5 , which is modified for the implementation in the first embodiment. The following only describes the differences between this embodiment and the first embodiment, 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 submodule, wherein the gate of the drive transistor is coupled to 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 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 electrode of the fifth transistor M5 is connected to The second terminal of the second capacitor C2 is coupled to the second terminal of the fifth transistor M5 and the gate of the driving transistor M0 is coupled.

The working process of the pixel circuit provided by the embodiment of the present invention will be described below in conjunction with the circuit timing diagram. In the following description, 1 represents high level and 0 represents low level. It should be noted that 1 and 0 are logic levels, which are only used 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 buffering phase T3', and a lighting phase T4. Wherein, 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 provides the voltage Vref of the signal at the data signal terminal Data to the second pole 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 S of the driving transistor M0 The voltage of S is Vdd. The turned-on third transistor M3 provides the signal of the second pole D of the driving transistor M0 to the first pole of the light emitting device 104, and the first pole of the light emitting device 104 is initialized. Since Reset=1, the first transistor M1 is turned on, and the voltage Vdd of the first pole S of the driving transistor M0 is provided 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 voltages 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 voltages 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 at the data signal terminal Data to the second pole D of the driving transistor M0. The turned-on fifth transistor M5 conducts the second end of the second capacitor C2 with the gate G of the driving transistor M0. Since Reset=1, the first transistor M1 is turned on, the first pole S of the driving transistor M0 is turned on with the gate G, so that the driving transistor M0 forms a diode structure, the gate voltage of the driving transistor M0 is discharged, and the gate voltage of the driving transistor M0 When the voltage changes from Vdd to Vref+Vth, the driving transistor M0 is turned off, and Vdd-Vref>Vth. Where 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 terminal 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;

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. Because 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, the signal of the gate G of the driving 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 terminal 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 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;

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 moment, the voltage at both ends of the first capacitor C1 is the same as the voltage at the gate G and the second electrode D of the driving transistor M0 in the data writing stage T3, namely The first capacitor C1 stores the voltage of the gate G of the driving transistor M0 and the second terminal D of the driving transistor M0 , and the second capacitor C2 stores the voltage of the first voltage terminal VDD and the first terminal of the fifth transistor M5 .

Lighting 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 pole 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 of the driving transistor M0 and the second pole D is:

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

in, μ _n represents the mobility of the driving transistor DT, C _ox is the capacitance of the gate oxide layer per unit area, For the width-to-length 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 no longer affected by the threshold voltage Vth of the driving transistor M0 and the voltage drop of the first voltage source VDD, thus improving the performance of the driving transistor M0 due to the process and The long time operation causes the threshold voltage drift and the 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 701-704;

Step 701, 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 scanning signal terminal; the threshold compensation module resets the gate of the driving transistor in response to the signal of the reset signal terminal; The light emission control module provides the signal of the first voltage end to the first electrode of the drive transistor in response to the signal of the light emission control end, and conducts the second electrode of the drive transistor with the light emitting device;

Step 702, 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 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 provides the signal of the first voltage terminal to the first pole of the driving transistor in response to the signal of the light-emitting control terminal, 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 that the light emitting device is driven to emit light by 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 embodiment 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 . Certainly, the above-mentioned display device provided by the embodiment of the present invention may also be any product or component with a display function such as a mobile phone, a tablet computer, a television set, a monitor, a notebook computer, a digital photo frame, and a navigator. The 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 they be regarded as limitations on the present invention.

The pixel circuit provided by the embodiments of the present invention, its driving method, and display device include a driving transistor, a data writing module, a light emission 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 at the data signal terminal is provided to the second pole of the drive transistor; the threshold compensation module is configured to reset the gate of the drive transistor and compensate the threshold voltage of the drive transistor in response to the signal at the reset signal terminal; the light emission control module is It is configured to respond to the signal of the light-emitting control terminal, provide the signal of the first voltage terminal to the first pole of the driving transistor, and conduct the second pole of the driving transistor with the light-emitting device; the driving transistor is configured according to the gate voltage of the driving transistor and the second pole voltage to generate a driving current, so as to drive the light emitting device to emit light through the driving current. Therefore, the pixel circuit provided by the embodiment of the present invention can compensate the threshold voltage of the driving transistor through the mutual 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. Moreover, through the mutual 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 (10)

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.

2. The pixel circuit of claim 1, wherein the threshold compensation module comprises a first sub-module, a second sub-module, and a third 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.

3. the pixel circuit according to claim 2, wherein the first sub-module comprises a first capacitor, a first terminal of the first capacitor is coupled to the second pole of the driving transistor, and a second terminal of the first capacitor is coupled to the gate of the driving transistor; and/or the presence of a gas in the gas,

The third sub-module includes: and one end of the second capacitor is coupled with the first voltage end, and the second end of the second capacitor is coupled with the grid electrode of the driving transistor.

4. the pixel circuit of claim 3, wherein the threshold compensation module further comprises 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;

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 a signal of the scan signal terminal.

5. the pixel circuit according to claim 4, wherein 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.

6. The pixel circuit according to claim 2, wherein the second sub-module comprises a first transistor, a gate of the first transistor is coupled to the reset signal terminal, a first pole of the first transistor is coupled to a first pole of the driving transistor, and a second pole of the first transistor is coupled to the gate of the driving transistor.

7. 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.

8. 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.

9. a display device comprising the pixel circuit according to any one of claims 1 to 8.

10. A driving method using the pixel circuit according to any one of claims 1 to 8, 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.