CN111105749A

CN111105749A - Pixel circuit, pixel driving method and display device

Info

Publication number: CN111105749A
Application number: CN202010039927.1A
Authority: CN
Inventors: 刘伟星; 王铁石; 秦纬; 徐智强; 杨军星; 滕万鹏
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2020-05-05
Anticipated expiration: 2040-01-15
Also published as: CN111105749B

Abstract

The invention provides a pixel circuit, a pixel driving method and a display device. The pixel circuit comprises a light-emitting element, a driving circuit, a light-emitting control circuit and a protection circuit, wherein the protection circuit is electrically connected with a protection end; the protection end is electrically connected with the first end of the light-emitting control circuit; the protection circuit is used for controlling the potential of the protection end when the light-emitting control circuit starts to control the communication between the first end of the light-emitting control circuit and the second end of the light-emitting control circuit in the light-emitting stage, so that the absolute value of the difference value between the potential of the protection end and the potential of the control end of the light-emitting control circuit is smaller than a preset difference value. The invention solves the problem that the capacitive coupling action easily causes the breakdown of the light-emitting control transistor at the beginning of the light-emitting stage in the prior pixel circuit.

Description

Pixel circuit, pixel driving method and display device

Technical Field

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

Background

In the existing OLED (organic light emitting diode) pixel driving circuit, because the current intensity directly influences the screen gray scale, in the process, the process uniformity problem and the TFT (thin film transistor) are operated for a long time to cause the characteristic drift of the TFT, finally, the screen brightness gray scale is different, and the display effect is influenced. In order to solve the uniformity problem, the prior art proposes an OLED pixel circuit compensation scheme, which utilizes the capacitive coupling relationship to perform threshold voltage compensation to avoid the phenomenon of uneven brightness, however, in the prior art, at the beginning of the light-emitting stage, the capacitive coupling effect easily causes the light-emitting control transistor to be broken down.

Disclosure of Invention

The invention mainly aims to provide a pixel circuit, a pixel driving method and a display device, which solve the problem that a light-emitting control transistor is easy to break down due to capacitive coupling action at the beginning of a light-emitting stage in the conventional pixel circuit.

In order to achieve the above object, the present invention provides a pixel circuit including a light emitting element, a driving circuit, a light emission control circuit, and a protection circuit, wherein,

the first end of the driving circuit is electrically connected with a power supply voltage end; the control end of the light-emitting control circuit is electrically connected with the light-emitting control line; the drive circuit is used for generating a drive current flowing from a first end of the drive circuit to a second end of the drive circuit under the control of the potential of a control end of the drive circuit;

the protection circuit is electrically connected with the protection end;

a first end of the light-emitting control circuit is electrically connected with a second end of the driving circuit, a second end of the light-emitting control circuit is electrically connected with a first electrode of the light-emitting element, a second electrode of the light-emitting element is electrically connected with a cathode voltage end, and the protection end is electrically connected with a second end of the light-emitting control circuit; or, the second end of the driving circuit is electrically connected to the first electrode of the light emitting element, the first end of the light emission control circuit is electrically connected to the second electrode of the light emitting element, the second end of the light emission control circuit is electrically connected to the cathode voltage terminal, and the protection terminal is electrically connected to the first end of the light emission control circuit;

the light-emitting control circuit is used for controlling the communication between the first end of the light-emitting control circuit and the second end of the light-emitting control circuit under the control of a light-emitting control signal provided by the light-emitting control line;

the protection circuit is used for controlling the potential of the protection end when the light-emitting control circuit starts to control the communication between the first end of the light-emitting control circuit and the second end of the light-emitting control circuit in a light-emitting stage, so that the absolute value of the difference between the potential of the protection end and the potential of the control end of the light-emitting control circuit is smaller than a preset difference.

In practice, when the first terminal of the light-emitting control circuit is electrically connected to the second terminal of the driving circuit, the second terminal of the light-emitting control circuit is electrically connected to the first electrode of the light-emitting element, the second electrode of the light-emitting element is electrically connected to the cathode voltage terminal, and the protection terminal is electrically connected to the second terminal of the light-emitting control circuit, the protection circuit includes a protection transistor;

the control electrode of the protection transistor and the first electrode of the protection transistor are both electrically connected with the protection end, and the second electrode of the protection transistor is electrically connected with the first voltage end;

the protection transistor is a p-type transistor.

In practice, when the second terminal of the driving circuit is electrically connected to the first terminal of the light emitting element, the first terminal of the light emission control circuit is electrically connected to the second terminal of the light emitting element, the second terminal of the light emission control circuit is electrically connected to the cathode voltage terminal, and the protection terminal is electrically connected to the first terminal of the light emission control circuit, the protection circuit includes a protection transistor;

the protection transistor is an n-type transistor.

In practice, the driving circuit includes a driving transistor, and the light emission control circuit includes a light emission control transistor;

the control electrode of the driving transistor is a control end of the driving circuit, the first electrode of the driving transistor is a first end of the driving circuit, and the second electrode of the driving transistor is a second end of the driving circuit;

the control electrode of the light-emitting control transistor is the control end of the light-emitting control circuit, the first electrode of the light-emitting control transistor is the first end of the light-emitting control circuit, and the second electrode of the light-emitting control transistor is the second end of the light-emitting control circuit.

In practice, the pixel circuit of the present invention further comprises a storage capacitor, a data writing circuit, a compensation control circuit and an initialization circuit, wherein,

the first end of the storage capacitor is electrically connected with the control end of the driving circuit;

the data writing circuit is used for controlling to write the data voltage on the data line into the second end of the storage capacitor under the control of the grid driving signal provided by the grid line;

the compensation control circuit is used for controlling the communication between the control end of the drive circuit and the second end of the drive circuit under the control of the grid drive signal;

the initialization circuit is used for controlling the supply of an initialization voltage to the second end of the storage capacitor under the control of an initialization control signal provided by an initialization control line.

In practice, the pixel circuit of the present invention further comprises a voltage control circuit;

the voltage control circuit is used for controlling the supply of the initialization voltage to the second end of the storage capacitor under the control of a voltage holding control signal provided by a voltage holding control line.

In practice, the data write circuit includes a data write transistor, the compensation control circuit includes a compensation control transistor, and the initialization circuit includes an initialization transistor;

a control electrode of the data writing transistor is electrically connected with the grid line, a first electrode of the data writing transistor is electrically connected with the data line, and a second electrode of the data writing transistor is electrically connected with a second end of the storage capacitor;

a control electrode of the compensation control transistor is electrically connected with the grid line, a first electrode of the compensation control transistor is electrically connected with a control end of the driving circuit, and a second electrode of the compensation control transistor is electrically connected with a second end of the storage capacitor;

a control electrode of the initialization transistor is electrically connected with the initialization control line, a first electrode of the initialization transistor is electrically connected with an initialization voltage line, and a second electrode of the initialization transistor is electrically connected with a second end of the storage capacitor; the initialization voltage line is used for providing the initialization voltage.

In practice, the voltage control circuit includes a voltage control transistor;

and the control electrode of the voltage control transistor is electrically connected with the voltage holding control line, the first electrode of the voltage control transistor is electrically connected with an initialization voltage line, and the second electrode of the voltage control transistor is electrically connected with the second end of the storage capacitor.

In practice, the pixel circuit of the invention further comprises a first storage capacitor, a second storage capacitor, a data writing circuit and a compensation control circuit;

the first end of the first storage capacitor is electrically connected with the power supply voltage end, the second end of the first storage capacitor is electrically connected with the first end of the second storage capacitor, and the second end of the second storage capacitor is electrically connected with the control end of the driving circuit;

the data writing circuit is used for writing data voltage on a data line into the first end of the second storage capacitor under the control of a scanning signal provided by a scanning line;

the compensation control circuit is used for controlling the communication between the control end of the driving circuit and the second end of the driving circuit and controlling the communication between the first end of the second storage capacitor and the cathode voltage end under the control of a compensation control signal provided by a compensation control line.

In practice, the data write circuit includes a data write transistor;

the grid electrode of the data writing transistor is electrically connected with the scanning line, the first pole of the data writing transistor is electrically connected with the data line, and the second pole of the data writing transistor is electrically connected with the first end of the second storage capacitor;

the compensation control circuit comprises a first compensation control transistor and a second compensation control transistor;

a control electrode of the first compensation control transistor is electrically connected with the compensation control line, a first electrode of the first compensation control transistor is electrically connected with a control end of the driving circuit, and a second electrode of the first compensation control transistor is electrically connected with a second end of the driving circuit;

the control electrode of the second compensation control transistor is electrically connected with the compensation control line, the first electrode of the second compensation control transistor is electrically connected with the first end of the second storage capacitor, and the second electrode of the first compensation control transistor is electrically connected with the cathode voltage end.

The present invention also provides a pixel driving method for driving the pixel circuit, the pixel driving method comprising:

in the light-emitting stage, the driving circuit generates a driving current flowing from the first end of the driving circuit to the second end of the driving circuit under the control of the potential of the control end of the driving circuit, and the light-emitting control circuit controls the communication between the first end of the light-emitting control circuit and the second end of the light-emitting control circuit under the control of a light-emitting control signal provided by a light-emitting control line;

in the light emitting stage, when the light emitting control circuit starts to control the connection between the first end of the light emitting control circuit and the second end of the light emitting control circuit, the protection circuit controls the potential of the protection end so that the absolute value of the difference between the potential of the protection end and the potential of the control end of the light emitting control circuit is smaller than a preset difference.

The invention also provides a display device which comprises the pixel circuit.

Compared with the prior art, the pixel circuit, the pixel driving method and the display device provided by the invention are provided with the protection circuit, the protection circuit controls the potential of the protection end when the light-emitting control circuit starts to control the communication between the first end of the light-emitting control circuit and the second end of the light-emitting control circuit in the light-emitting stage, so that the absolute value of the difference between the potential of the protection end and the potential of the control end of the light-emitting control circuit is smaller than a preset difference, and the light-emitting control transistor included in the light-emitting control circuit is prevented from being broken down at the moment of starting the light-emitting stage.

Drawings

Fig. 1 is a structural diagram of a pixel circuit according to an embodiment of the present invention;

fig. 2 is a block diagram of a pixel circuit according to another embodiment of the present invention;

fig. 3 is a block diagram of a pixel circuit according to yet another embodiment of the present invention;

fig. 4 is a structural diagram of a pixel circuit according to still another embodiment of the present invention;

FIG. 5 is a block diagram of a pixel circuit according to another embodiment of the present invention;

FIG. 6 is a circuit diagram of a first embodiment of a pixel circuit according to the present invention;

FIG. 7 is a timing diagram illustrating the operation of a first embodiment of the pixel circuit according to the present invention;

fig. 8A is a schematic diagram illustrating an operation state of the first embodiment of the pixel circuit in the initialization stage S1 according to the present invention;

FIG. 8B is a diagram illustrating the operation of the first embodiment of the pixel circuit in the compensation stage S2;

fig. 8C is a schematic diagram of the operation state of the first embodiment of the pixel circuit in the voltage holding stage S3;

fig. 8D is a schematic diagram of the operation state of the first embodiment of the pixel circuit in the light-emitting stage S4 according to the present invention;

FIG. 9 is a circuit diagram of a second embodiment of a pixel circuit according to the present invention;

FIG. 10 is a timing diagram illustrating the operation of a second embodiment of the pixel circuit according to the present invention;

fig. 11A is a schematic diagram illustrating an operation state of the second embodiment of the pixel circuit in the initialization stage S1 according to the present invention;

FIG. 11B is a diagram illustrating the operation of the second embodiment of the pixel circuit in the compensation stage S2;

fig. 11C is a schematic diagram illustrating an operation state of the second embodiment of the pixel circuit in the voltage holding stage S3;

fig. 11D is a schematic diagram of an operating state of the second embodiment of the pixel circuit in the light-emitting stage S4;

FIG. 12 is a circuit diagram of a third embodiment of a pixel circuit according to the present invention;

FIG. 13 is a timing diagram illustrating the operation of a third embodiment of the pixel circuit according to the present invention;

fig. 14A is a schematic diagram illustrating an operation state of the third embodiment of the pixel circuit in the initialization stage S1 according to the present invention;

FIG. 14B is a diagram illustrating the operation of the third embodiment of the pixel circuit in the compensation stage S2;

FIG. 14C is a diagram illustrating the operation of the third embodiment of the pixel circuit in the data writing stage S0;

fig. 14D is a schematic diagram of an operation state of the third embodiment of the pixel circuit in the light-emitting stage S4;

FIG. 15A is a diagram illustrating a relationship between the voltage Vp at the protection terminal p and the time t in the first embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to-2V;

FIG. 15B is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to-2V;

FIG. 15C is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the first embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to-1.5V;

FIG. 15D is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to-1.5V;

FIG. 15E is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the first embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to-1V;

FIG. 15F is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to-1V;

FIG. 16A is a diagram illustrating a relationship between the voltage Vp at the protection terminal p and the time t in the second embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to-2V;

FIG. 16B is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to-2V;

FIG. 16C is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the second embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to-1.5V;

FIG. 16D is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to-1.5V;

FIG. 16E is a diagram illustrating the correspondence relationship between the voltage Vp at the protection terminal p and the time t in the second embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to-1V;

fig. 16F is a diagram illustrating a correspondence relationship between the voltage Vp of the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to-1V.

FIG. 17A is a diagram illustrating a relationship between the voltage Vp at the protection terminal p and the time t in the third embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to 5V;

fig. 17B is a diagram illustrating a correspondence relationship between the voltage Vp of the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to 5V;

FIG. 17C is a diagram illustrating a relationship between the voltage Vp at the protection terminal p and the time t in the third embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to 6V;

fig. 17D is a diagram illustrating a correspondence relationship between the voltage Vp of the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to 6V;

FIG. 17E is a diagram illustrating the relationship between the voltage Vp at the protection terminal p and the time t in the third embodiment of the pixel circuit according to the invention when the data voltage Vdata is equal to 7V;

fig. 17F is a diagram illustrating a correspondence relationship between the voltage Vp of the protection terminal p and the time t in the conventional pixel circuit when the data voltage Vdata is equal to 7V.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The transistors used in all embodiments of the present invention may be transistors, thin film transistors, or field effect transistors or other devices with the same characteristics. In the embodiment of the present invention, in order to distinguish two poles of the transistor except the control pole, one pole is called a first pole, and the other pole is called a second pole.

In practical operation, when the transistor is a triode, the control electrode may be a base electrode, the first electrode may be a collector electrode, and the second electrode may be an emitter electrode; alternatively, the control electrode may be a base electrode, the first electrode may be an emitter electrode, and the second electrode may be a collector electrode.

In practical operation, when the transistor is a thin film transistor or a field effect transistor, the control electrode may be a gate electrode, the first electrode may be a drain electrode, and the second electrode may be a source electrode; alternatively, the control electrode may be a gate electrode, the first electrode may be a source electrode, and the second electrode may be a drain electrode.

The pixel circuit according to the embodiment of the present invention includes a light emitting element, a driving circuit, a light emission control circuit, and a protection circuit,

the protection circuit is electrically connected with the protection end;

The pixel circuit according to the embodiment of the present invention is provided with a protection circuit, where the protection circuit is configured to control a potential of the protection terminal in a light emitting stage when the light emission control circuit starts to control communication between the first terminal of the light emission control circuit and the second terminal of the light emission control circuit, so that an absolute value of a difference between the potential of the protection terminal and a potential of the control terminal of the light emission control circuit is smaller than a predetermined difference, so as to prevent a light emission control transistor included in the light emission control circuit from being broken down at an instant when the light emission stage starts.

In a specific implementation, the light emitting element may be an organic light emitting diode, the first pole of the light emitting element may be an anode of the organic light emitting diode, and the second pole of the light emitting element may be a cathode of the organic light emitting diode, but not limited thereto.

As shown in fig. 1, the pixel circuit according to the embodiment of the present invention includes a light emitting element EL, a drive circuit 11, a light emission control circuit 12, and a protection circuit 13, wherein,

the first end of the driving circuit 11 is electrically connected with a power supply voltage end; the control end of the light-emitting control circuit 12 is electrically connected with a light-emitting control line em (n); the driving circuit 11 is used for generating a driving current flowing from a first end of the driving circuit 11 to a second end of the driving circuit 11 under the control of the potential of a control end of the driving circuit 11; the power supply voltage end is used for providing power supply voltage VDD;

the protection circuit 13 is electrically connected with the protection terminal p;

a first end of the light-emitting control circuit 12 is electrically connected to a second end of the driving circuit 11, a second end of the light-emitting control circuit 12 is electrically connected to a first electrode of the light-emitting element EL, a second electrode of the light-emitting element EL is electrically connected to a cathode voltage terminal, and the protection terminal p is electrically connected to a second end of the light-emitting control circuit 12; the cathode voltage end is used for providing a cathode voltage VSS;

the light-emitting control circuit 12 is configured to control communication between a first end of the light-emitting control circuit 12 and a second end of the light-emitting control circuit 12 under control of a light-emitting control signal provided by the light-emitting control line em (n);

the protection circuit 13 is configured to control, in a light emitting phase, when the light emission control circuit 12 starts to control communication between the first terminal of the light emission control circuit 12 and the second terminal of the light emission control circuit 12, the potential of the protection terminal p such that an absolute value of a difference between the potential of the protection terminal p and the potential of the control terminal of the light emission control circuit 12 is smaller than a predetermined difference.

In the embodiment of the pixel circuit shown in fig. 1 of the present invention, at the beginning of the light emitting phase, when the light emitting control circuit 12 turns on the connection between the second terminal of the driving circuit 11 and the first pole of the light emitting element EL, the potential of the protection terminal p is coupled to be pulled down, and the light emitting control transistor may be broken down, and the protection circuit 13 provides a relatively high voltage to the protection terminal p to prevent the light emitting control transistor from being broken down.

In the embodiment of the pixel circuit shown in fig. 1, the protection circuit 13 may include a protection transistor, a control electrode of the protection transistor and a first electrode of the protection transistor are both electrically connected to the protection terminal, a second electrode of the protection transistor is electrically connected to the first voltage terminal, and the protection transistor is a p-type transistor.

According to a specific embodiment, when the first terminal of the light emission control circuit is electrically connected to the second terminal of the driving circuit, the second terminal of the light emission control circuit is electrically connected to the first terminal of the light emitting element, the second terminal of the light emitting element is electrically connected to the cathode voltage terminal, and the protection terminal is electrically connected to the second terminal of the light emission control circuit, the protection circuit includes a protection transistor;

the protection transistor is a p-type transistor.

As shown in fig. 2, the pixel circuit according to the embodiment of the present invention may include a light emitting element EL, a driving circuit 11, a light emission control circuit 12, and a protection circuit 13, wherein,

a second terminal of the driving circuit 11 is electrically connected to a first terminal of the light emitting element EL, a first terminal of the light emission control circuit 12 is electrically connected to a second terminal of the light emitting element EL, a second terminal of the light emission control circuit 12 is electrically connected to the cathode voltage terminal, and the protection terminal p is electrically connected to the first terminal of the light emission control circuit 12; the cathode voltage end is used for providing a cathode voltage VSS;

In the embodiment of the pixel circuit shown in fig. 2, at the beginning of the light emitting period, when the light emitting control circuit 12 turns on the connection between the second electrode of the light emitting element EL and the cathode voltage terminal, the potential of the protection terminal p is coupled to be pulled up, and the light emitting control transistor may be broken down, and the protection circuit 13 provides a relatively low voltage to the protection terminal p to prevent the light emitting control transistor from being broken down.

In the embodiment of the pixel circuit shown in fig. 2, the protection circuit 13 may include a protection transistor, a control electrode of the protection transistor and a first electrode of the protection transistor are both electrically connected to the protection terminal, a second electrode of the protection transistor is electrically connected to the first voltage terminal, and the protection transistor is an n-type transistor.

According to another specific embodiment, when the second terminal of the driving circuit is electrically connected to the first terminal of the light emitting element, the first terminal of the light emission control circuit is electrically connected to the second terminal of the light emitting element, the second terminal of the light emission control circuit is electrically connected to the cathode voltage terminal, and the protection terminal is electrically connected to the first terminal of the light emission control circuit, the protection circuit includes a protection transistor;

the protection transistor is an n-type transistor.

Specifically, the driving circuit may include a driving transistor, and the light emission control circuit may include a light emission control transistor;

According to a specific implementation manner, the pixel circuit according to the embodiment of the invention further includes a storage capacitor, a data writing circuit, a compensation control circuit, and an initialization circuit, wherein,

Specifically, the pixel circuit according to the embodiment of the present invention further includes a voltage control circuit;

In specific implementation, the pixel circuit may further include a storage capacitor, a data writing circuit, a compensation control circuit, an initialization circuit, and a voltage control circuit; the display period may include an initialization stage, a compensation stage, a voltage holding stage, and a light emitting stage, which are sequentially set;

in the initialization stage, the initialization circuit supplies initialization voltage to the second end of the storage capacitor under the control of the initialization control signal so as to reset the storage capacitor and prevent the voltage of the previous frame of picture display time which is remained at the second end of the storage capacitor from influencing the display;

in the compensation stage, the data writing circuit controls to write data voltage into the second end of the storage capacitor under the control of the gate drive signal, and the compensation control circuit controls the communication between the control end of the drive circuit and the second end of the drive circuit under the control of the gate drive signal so as to perform data writing and threshold voltage compensation;

in the voltage holding stage, the voltage control circuit controls to provide the initialization voltage to the second end of the storage capacitor under the control of the voltage holding control signal so as to correspondingly change the potential of the control end of the driving circuit;

in the light emitting stage, the light emitting control circuit conducts the connection between the first end of the light emitting control circuit and the second end of the light emitting control circuit, and the driving circuit drives the light emitting element to emit light;

at the instant when the light emission phase starts, the protection circuit controls the potential of the protection terminal p so that the absolute value of the difference between the potential of the protection terminal p and the potential of the control terminal of the light emission control circuit 12 is smaller than a predetermined difference;

in the light emitting stage, when the driving circuit drives the light emitting element to emit light, the protection transistor included in the protection circuit is turned off.

As shown in fig. 3, the pixel circuit according to the embodiment of the present invention may further include a storage capacitor Cst, a data writing circuit 14, a compensation control circuit 15, an initialization circuit 16, and a voltage control circuit 17 on the basis of the embodiment of the pixel circuit shown in fig. 1, wherein,

a first end of the storage capacitor Cst is electrically connected to a control end of the driving circuit 11;

the Data writing circuit 14 is electrically connected to the gate line g (n), the Data line Data and the second end of the storage capacitor Cst, and is configured to control writing of the Data voltage on the Data line Data into the second end of the storage capacitor Cst under the control of the gate driving signal provided by the gate line g (n);

the compensation control circuit 15 is electrically connected to the gate line g (n), the control terminal of the driving circuit 11, and the second terminal of the driving circuit 11, respectively, and is configured to control the connection between the control terminal of the driving circuit 11 and the second terminal of the driving circuit 11 under the control of the gate driving signal;

the initialization circuit 16 is electrically connected to the initialization control line G (n-1), the initialization voltage line, and the second end of the storage capacitor Cst, respectively, and is configured to control the initialization voltage Vint to be supplied to the second end of the storage capacitor Cst under the control of an initialization control signal supplied by the initialization control line G (n-1); the initialization voltage line is used for providing the initialization voltage Vint;

the voltage control circuit 17 is respectively connected to the voltage holding control line G (n +1), the initialization voltage line, and the second terminal of the storage capacitor Cst, and is configured to control the initialization voltage Vint to be supplied to the second terminal of the storage capacitor Cst under the control of a voltage holding control signal supplied from the voltage holding control line G (n + 1).

When the embodiment of the pixel circuit shown in fig. 3 of the present invention is in operation, the display period may include an initialization stage, a compensation stage, a voltage holding stage, and a light emitting stage, which are sequentially arranged;

in the initialization stage, the initialization circuit 16 provides the initialization voltage to the second terminal of the storage capacitor Cst under the control of the initialization control signal to reset the storage capacitor Cst, so as to prevent the voltage of the previous frame display time remaining at the second terminal of the storage capacitor Cst from affecting the display;

in the compensation stage, the data writing circuit 14 controls to write the data voltage into the second terminal of the storage capacitor Cst under the control of the gate driving signal, and the compensation control circuit 15 controls the connection between the control terminal of the driving circuit 11 and the second terminal of the driving circuit 11 under the control of the gate driving signal, so as to perform data writing and threshold voltage compensation;

in the voltage holding phase, the voltage control circuit 17 controls the supply of the initialization voltage Vint to the second terminal of the storage capacitor Cst under the control of the voltage holding control signal to correspondingly change the potential of the control terminal of the driving circuit 11;

in the light emitting phase, the light emitting control circuit 12 turns on the connection between the second terminal of the driving circuit 11 and the first pole of the light emitting element EL under the control of the light emitting control signal, and the driving circuit 11 drives the light emitting element EL to emit light;

at the instant when the light emission phase starts, the protection circuit controls the potential of the protection terminal p so that the absolute value of the difference between the potential of the protection terminal p and the potential of the control terminal of the light emission control circuit 12 is smaller than a predetermined difference to prevent the light emission control transistor included in the light emission control circuit 12 from being broken down;

in the light emitting phase, when the driving circuit 11 drives the light emitting element to emit light, the protection transistor included in the protection circuit 13 is turned off.

As shown in fig. 4, the pixel circuit according to the embodiment of the present invention may further include a storage capacitor Cst, a data writing circuit 14, a compensation control circuit 15, an initialization circuit 16, and a voltage control circuit 17 on the basis of the embodiment of the pixel circuit shown in fig. 2, wherein,

When the embodiment of the pixel circuit shown in fig. 4 of the present invention is in operation, the display period may include an initialization phase, a compensation phase, a voltage holding phase, and a light emitting phase, which are sequentially set;

in the light-emitting stage, the light-emitting control circuit 12 turns on the connection between the second electrode of the light-emitting element EL and the cathode voltage terminal under the control of the light-emitting control signal, and the driving circuit 11 drives the light-emitting element EL to emit light;

Specifically, the data writing circuit may include a data writing transistor, the compensation control circuit includes a compensation control transistor, and the initialization circuit includes an initialization transistor;

Specifically, the voltage control circuit may include a voltage control transistor;

According to another specific embodiment, the pixel circuit further includes a first storage capacitor, a second storage capacitor, a data writing circuit, and a compensation control circuit;

As shown in fig. 5, on the basis of the embodiment of the pixel circuit shown in fig. 1, the pixel circuit according to the present invention may further include a first storage capacitor Cst1, a second storage capacitor Cst2, a data writing circuit 14, and a compensation control circuit 15;

a first terminal of the first storage capacitor Cst1 is electrically connected to the power voltage terminal, a second terminal of the first storage capacitor Cst1 is electrically connected to a first terminal of the second storage capacitor Cst2, and a second terminal of the second storage capacitor Cst2 is electrically connected to the control terminal of the driving circuit 11; the power supply voltage end is used for providing power supply voltage VDD;

the Data writing circuit 14 is electrically connected to the scan line scan (n), the Data line Data and the first end of the second storage capacitor Cst2, respectively, and is configured to write the Data voltage on the Data line Data into the first end of the second storage capacitor Cst2 under the control of the scan signal provided by the scan line scan (n);

the compensation control circuit 15 is electrically connected to the compensation control line SCAN (n-1), the control terminal of the driving circuit 11, the second terminal of the driving circuit 11, the first terminal of the second storage capacitor Cst2, and the cathode voltage terminal, respectively, and is configured to control the connection between the control terminal of the driving circuit 11 and the second terminal of the driving circuit 11 and the connection between the first terminal of the second storage capacitor Cst2 and the cathode voltage terminal under the control of a compensation control signal provided by the compensation control line SCAN (n-1); the cathode voltage terminal is used for providing a cathode voltage VSS.

In FIG. 5, node b is a node connected to the first terminal of Cst2, and node c is a node connected to the second terminal of Cst 2.

And in the embodiment shown in fig. 5, the light emitting element EL is an organic light emitting diode.

In the embodiment of the present invention, the scan line may be the same as the gate line, but is not limited thereto.

When the embodiment of the pixel circuit shown in fig. 5 of the present invention is in operation, the display period may include an initialization stage, a compensation stage, a data writing stage, and a light emitting stage, which are sequentially arranged;

in the initialization phase, the compensation control circuit 15 controls the first terminal of Cst2 to be connected to the cathode unit VSS under the control of the compensation control line SCAN (n-1), and controls the communication between the control terminal of the driving circuit 11 and the second terminal of the driving circuit 11, so that the potential of the node b is reset to VSS, and the light emission control circuit 12 controls the communication between the second terminal of the driving circuit 11 and the first terminal of the light emitting element EL under the control of the light emission control signal provided by the light emission control line em (n), so that the potential of the node c becomes VSS + Voled; where Voled is a threshold voltage of the light emitting element EL;

in the compensation phase, the compensation control circuit 15 controls the first terminal of Cst2 to be connected to the cathode unit VSS under the control of a compensation control signal provided by a compensation control line SCAN (n-1), and controls the control terminal of the driving circuit 11 to be connected to the second terminal of the driving circuit 11, so that the driving circuit 11 turns on the connection between the first terminal of Cst2 and the second terminal of the driving circuit 11, and the current charges the second storage capacitor Cst2 through the driving circuit 11 and the compensation control circuit 15 until the driving circuit 11 turns off the connection between the first terminal of Cst2 and the second terminal of the driving circuit 11, at this time, the potential of the node c becomes VDD + Vth, which is the threshold voltage of the driving transistor included in the driving circuit 11;

in the Data writing stage, the Data line Data provides a Data voltage Vdata, the Data writing circuit 14 writes the Data voltage Vdata on the Data line Data into a node b under the control of a scanning signal provided by a scanning line scan (n), the voltage of the node b is changed into Vdata, and the potential of the node c is changed into VDD + Vth + (Vdata-VSS);

in the light emitting stage, under the control of a light emitting control signal provided by a light emitting control line em (n), the connection between the second end of the driving circuit 11 and the first pole of the light emitting element EL is controlled to be conducted, and at this time, the potential of the node b is consistent with the potential of the node c, so that the driving current generated by the driving circuit 11 and used for driving the light emitting element EL to emit light is unrelated to Vth, the light emitting element EL is enabled to display stably, and the problems of uneven and unstable brightness are solved; wherein Vth is a threshold voltage of the driving transistor;

also, in the light emission phase, when the light emission control circuit 11 is just turned on, the potential of the protection terminal p is coupled and pulled down, and the protection circuit 13 controls the potential of the protection terminal p so that the absolute value of the difference between the potential of the protection terminal p and the potential of the control terminal of the light emission control circuit 12 is smaller than a predetermined difference to prevent the light emission control transistor included in the light emission control circuit 12 from being broken down;

in the light emitting period, when the light emitting element EL emits light, the potential of the protection terminal p is pulled high, and the protection circuit 13 stops controlling the potential of the protection terminal p.

Specifically, the data write circuit may include a data write transistor;

The pixel circuit according to the present invention is illustrated in three specific embodiments below.

As shown in fig. 6, on the basis of the embodiment of the pixel circuit shown in fig. 3, in the first embodiment of the pixel circuit according to the present invention,

the driving circuit includes a driving transistor T2, and the light emission control circuit includes a light emission control transistor T4; the protection circuit includes a protection transistor T7; the data write circuit includes a data write transistor T1, the compensation control circuit includes a compensation control transistor T3, the initialization circuit includes an initialization transistor T6; the voltage control circuit includes a voltage control transistor T5; the light-emitting element is an organic light-emitting diode (OLED);

a first end of Cst is electrically connected to node g, and a second end of Cst is electrically connected to node m;

the gate of T2 is electrically connected to the first terminal of Cst, the source of T2 is electrically connected to the supply voltage terminal, and the drain of T2 is electrically connected to the source of T4; the power supply voltage end is used for providing power supply voltage VDD;

the gate of T1 is electrically connected to the gate line g (n), the source of T1 is electrically connected to the Data line Data, and the drain of T1 is electrically connected to the second end of Cst;

the grid electrode of the T3 is electrically connected with the grid line G (n), the source electrode of the T3 is electrically connected with the grid electrode of the T2, and the drain electrode of the T3 is electrically connected with the drain electrode of the T2;

the grid electrode of the T4 is electrically connected with an emission control line EM (n), the source electrode of the T4 is electrically connected with the drain electrode of the T2, and the drain electrode of the T4 is electrically connected with the anode of the OLED; the cathode of the OLED is electrically connected with the cathode voltage end; the cathode voltage end is used for providing a cathode voltage VSS;

the gate of T5 is electrically connected to the voltage holding control line G (n +1), the source of T5 is electrically connected to the second terminal of Cst, and the drain of T5 is electrically connected to the initialization voltage line; the initialization voltage line is used for providing an initialization voltage Vint;

the gate of T6 is electrically connected to the initialization control line G (n-1), the source of T6 is electrically connected to the second terminal of Cst, and the drain of T6 is electrically connected to the initialization voltage line;

the grid electrode of the T7 and the drain electrode of the T7 are electrically connected with a protection terminal p, and the protection terminal p is electrically connected with the anode of the OLED;

the source of T7 is electrically connected to a first voltage terminal, which provides a first voltage Vcc.

In the first embodiment of the pixel circuit of the present invention, Vcc may be equal to 0V, VSS and Vint may be equal to-2.3V, and VDD may be 4.6V, but not limited thereto.

In the first embodiment of the pixel circuit according to the present invention, all the transistors are p-type thin film transistors, but not limited thereto.

When the first specific embodiment of the pixel circuit of the present invention operates, the display cycle includes sequentially setting an initialization stage S1, a compensation stage S2, a voltage holding stage S3, and a light emitting stage S4;

in the initialization stage S1, G (n-1) provides a low level, G (n), G (n +1) and em (n) all provide a high level, T6 is turned on to initialize the potential of the node m to Vint, resetting Cst;

in the compensation stage S2, G (n) provides a low level, G (n-1), G (n +1), and em (n) all provide a high level, Data provides a Data voltage Vdata, T1 and T3 are both turned on, other transistors are all turned off, the potential Vm of the node m is Vdata, T2 is turned on first, VDD charges Cst through the turned on T2 to raise Vg until T2 is turned off, the potential Vg of the node G is VDD + Vth, where Vth is a threshold voltage of T2;

in the voltage holding stage S3, G (n +1) provides low level, G (n), G (n-1) and EM (n) all provide high level, T5 is turned on, so that Vm jumps to Vint, and the gate potential of T2 jumps to VDD + Vth- (Vdata-Vint);

in the light emitting phase S4, em (n) provides a low level, G (n +1), G (n) and G (n-1) all provide a high level, T5 is turned on, Vg is VDD + Vth- (Vdata-Vint), at this time, T2 is in a saturation state, a gate-source voltage Vgs of T2 is VDD + Vth- (Vdata-Vint) -VDD-Vth-Vdata + Vint, and a driving current Ioled for driving the OLED to emit light by T2 is as follows:

Ioled＝K(Vgs-Vth)²＝K(Vth-Vdata+Vint-Vth)²＝K(Vint-Vdata)²；

k is a constant related to process design;

as can be seen, Ioled is independent of the threshold voltage of T2, so that the OLED display is stable, and the problems of uneven and unstable brightness are solved;

at the lighting stage S4, when T4 starts to turn on, the potential of the protection terminal p is coupled down, which may cause the breakdown of T4, based on which, T7 is provided for protecting T4, since the gate voltage of T7 drops, T7 is turned on, at which time Vcc pulls up the potential of the protection terminal p to prevent the breakdown of T4;

in the light emitting period S4, when the OLED emits light, the gate voltage of T7 is high and T7 is turned off.

the driving circuit 11 includes a driving transistor T2, and the light emission control circuit 12 includes a light emission control transistor T4; the protection circuit 13 includes a protection transistor T7; the data write circuit 14 includes a data write transistor T1, the compensation control circuit 15 includes a compensation control transistor T3, the initialization circuit 16 includes an initialization transistor T6; the voltage control circuit 17 includes a voltage control transistor T5; the light-emitting element is an organic light-emitting diode (OLED);

In operation of the first embodiment of the pixel circuit of the present invention, as shown in fig. 7, the display period includes an initialization stage S1, a compensation stage S2, a voltage holding stage S3, and a light emitting stage S4;

in the initialization stage S1, G (n-1) provides a low level, G (n), G (n +1) and em (n) all provide a high level, as shown in fig. 8A, T6 is turned on to initialize the potential of the node m to Vint, resetting Cst;

in the compensation stage S2, G (n) provides a low level, G (n-1), G (n +1), and em (n) all provide a high level, Data provides a Data voltage Vdata, as shown in fig. 8B, T1 and T3 are both turned on, other transistors are all turned off, the potential Vm of the node m is Vdata, T2 is turned on first, VDD charges Cst through the turned on T2 to raise Vg until T2 is turned off, the potential Vg of the node G is VDD + Vth, where Vth is a threshold voltage of T2;

in the voltage holding stage S3, G (n +1) provides low level, G (n), G (n-1) and EM (n) all provide high level, as shown in FIG. 8C, T5 is turned on, so that Vm jumps to Vint, and the gate potential of T2 also jumps to VDD + Vth- (Vdata-Vint);

in the lighting phase S4, em (n) provides low level, G (n +1), G (n) and G (n-1) all provide high level, as shown in fig. 8D, T4 is turned on, Vg is VDD + Vth- (Vdata-Vint), at this time, T2 is in saturation state, and the gate-source voltage Vgs of T2 is as follows:

Vgs＝VDD+Vth-(Vdata-Vint)-VDD＝Vth-Vdata+Vint；

the driving current Ioled for driving the OLED to emit light by T2 is as follows:

Ioled＝K(Vgs-Vth)²＝K(Vth-Vdata+Vint-Vth)²＝K(Vint-Vdata)²；

k is a constant related to process design;

In fig. 7, Vgh is high, and Vgl is low.

As shown in fig. 9, on the basis of the embodiment of the pixel circuit shown in fig. 4, in the second embodiment of the pixel circuit according to the present invention,

the gate of T2 is electrically connected to the first terminal of Cst, the source of T2 is electrically connected to the supply voltage terminal, and the drain of T2 is electrically connected to the anode of OLED; the power supply voltage end is used for providing power supply voltage VDD;

the grid electrode of the T4 is electrically connected with an emission control line EM (n), the source electrode of the T4 is electrically connected with the cathode of the OLED, and the drain electrode of the T4 is electrically connected with the cathode voltage end; the cathode voltage end is used for providing a cathode voltage VSS;

the grid electrode of the T7 and the drain electrode of the T7 are electrically connected with a protection terminal p, and the protection terminal p is electrically connected with the cathode of the OLED;

In a second embodiment of the pixel circuit according to the present invention, Vcc may be equal to 0V, VSS and Vint may be equal to-2.3V, and VDD may be 4.6V, but not limited thereto.

In a second embodiment of the pixel circuit according to the invention, T7 is an n-type thin film transistor, and other transistors are all p-type thin film transistors, but not limited thereto.

In fig. 9, Vgh is high, and Vgl is low.

In operation of the second embodiment of the pixel circuit of the present invention, as shown in fig. 10, the display period includes an initialization stage S1, a compensation stage S2, a voltage holding stage S3, and a light emitting stage S4;

in the initialization stage S1, G (n-1) provides a low level, G (n), G (n +1) and em (n) all provide a high level, as shown in fig. 11A, T6 is turned on to initialize the potential of the node m to Vint, resetting Cst;

in the compensation stage S2, G (n) provides a low level, G (n-1), G (n +1), and em (n) all provide a high level, Data provides a Data voltage Vdata, as shown in fig. 11B, T1 and T3 are both turned on, other transistors are all turned off, the potential Vm of the node m is Vdata, T2 is turned on first, VDD charges Cst through the turned on T2 to raise Vg until T2 is turned off, the potential Vg of the node G is VDD + Vth, where Vth is a threshold voltage of T2;

in the voltage holding stage S3, G (n +1) provides low level, G (n), G (n-1) and EM (n) all provide high level, as shown in FIG. 11C, T5 is turned on, so that Vm jumps to Vint, and the gate potential of T2 also jumps to VDD + Vth- (Vdata-Vint);

in the lighting phase S4, em (n) provides low level, G (n +1), G (n) and G (n-1) all provide high level, as shown in fig. 11D, T4 is turned on, Vg is VDD + Vth- (Vdata-Vint), at this time, T2 is in saturation, and the gate-source voltage Vgs of T2 is as follows:

Vgs＝VDD+Vth-(Vdata-Vint)-VDD＝Vth-Vdata+Vint；

Ioled＝K(Vgs-Vth)²＝K(Vth-Vdata+Vint-Vth)²＝K(Vint-Vdata)²；

k is a constant related to process design;

at the lighting stage S4, when T4 starts to turn on, the potential of the protection terminal p is coupled upwards, which may cause the breakdown of T4, based on which, T7 is provided for protecting T4, since the gate voltage of T7 drops, T7 is turned on, at which time Vcc pulls down the potential of the protection terminal p, preventing the breakdown of T4;

in the light emitting period S4, when the OLED emits light, the gate voltage of T7 is low, and T7 is turned off.

As shown in fig. 12, on the basis of the embodiment of the pixel circuit shown in fig. 5, in the third embodiment of the pixel circuit according to the present invention,

the driving circuit includes a driving transistor T2, and the light emission control circuit includes a light emission control transistor T4; the protection circuit includes a protection transistor T7; the data write circuit includes a data write transistor T1; the compensation control circuit includes a first compensation control transistor T01 and a second compensation control transistor T02; the light-emitting element is an organic light-emitting diode (OLED);

a first terminal of the first storage capacitor Cst1 is electrically connected to the power voltage terminal, a second terminal of the first storage capacitor Cst1 is electrically connected to a first terminal of the second storage capacitor Cst2, and a second terminal of the second storage capacitor Cst2 is electrically connected to the control terminal of the driving circuit 11;

the gate of the Data writing transistor T1 is electrically connected to the scan line scan (n), the source of the Data writing transistor T1 is electrically connected to the Data line Data, and the drain of the Data writing transistor T1 is electrically connected to the first end of the second storage capacitor Cst 2;

the gate of the first compensation control transistor T01 is electrically connected to the compensation control line SCAN (n-1), the source of the first compensation control transistor T01 is electrically connected to the gate of T2, and the drain of the first compensation control transistor T01 is electrically connected to the drain of T2;

a gate of the second compensation control transistor T02 is electrically connected to the compensation control line SCAN (n-1), a source of the second compensation control transistor T02 is electrically connected to a power supply voltage terminal, and a drain of the first compensation control transistor T02 is electrically connected to a first terminal of Cst 2; the cathode voltage end is used for providing a cathode voltage VSS;

the gate of the driving transistor T2 is electrically connected to the second terminal of Cst2, the source of the driving transistor T2 is electrically connected to the supply voltage terminal, and the drain of the driving transistor T2 is electrically connected to the source of the emission control transistor T4;

the grid electrode of the light-emitting control transistor T4 is electrically connected with a light-emitting control line EM (n), the drain electrode of the light-emitting control transistor T4 is electrically connected with the anode of the OLED, and the cathode of the OLED is electrically connected with the cathode voltage end; the cathode voltage end is used for providing a cathode voltage VSS;

the gate and drain of T7 are electrically connected to the anode of the OLED, and the source of T7 is electrically connected to a first voltage terminal for providing a first voltage Vcc.

In FIG. 12, node b is a node connected to the first terminal of Cst2, and node c is a node connected to the second terminal of Cst2

In the third embodiment of the pixel circuit shown in fig. 12, all the transistors are p-type thin film transistors, but not limited thereto.

In a third embodiment of the pixel circuit according to the present invention, Vcc may be equal to 0V, VSS and Vint may be equal to-2.3V, and VDD may be 5.6V, but not limited thereto.

As shown in fig. 13, when the third embodiment of the pixel circuit shown in fig. 12 of the present invention is operated, the display period includes an initialization phase S1, a compensation phase S2, a data writing phase S0 and a light emitting phase S4 which are sequentially arranged;

in the initialization stage S1, SCAN (n-1) provides low level, SCAN (n) provides high level, em (n) provides low level, as shown in fig. 14A, T02 and T01 are turned on, T4 is turned on, T1 is turned off, the potential of the node b is reset to VSS, the potential of the node C is VSS + Voled, where Voled is the threshold voltage of the OLED;

in the compensation phase S2, SCAN (n-1) provides low level, SCAN (n) provides high level, em (n) provides high level, as shown in fig. 14B, T02 and T01 are turned on, T1 and T4 are turned off, T2 is turned on at the beginning of the compensation phase S2, current charges Cst2 through the turned-on T2 and T01 to raise the potential of the node c until the potential of the node c becomes VDD + Vth, and T2 is turned off, where Vth is the threshold voltage of T2;

in the Data writing phase S0, SCAN (n) provides low level, SCAN (n-1) and em (n) provide high level, Data line Data provides Data voltage Vdata, as shown in fig. 14C, T1 is turned on, T02, T01 and T4 are all turned off, the potential of node b changes from VSS to Vdata, and the potential of node C jumps to VDD + Vth + Vdata-VSS;

in the light emission phase S4, em (n) provides a low level, and SCAN (n-1) and SCAN (n) both provide a high level, as shown in fig. 14D, T2 and T4 are turned on, and the potential of the node b and the potential of the node c coincide with the data writing phase S0, when the gate-source voltage Vgs of T2 is as follows:

Vgs＝VDD+Vth+Vdata-VSS-VDD＝Vdata-VSS+Vth；

Ioled＝K(Vgs-Vth)²＝K(Vth-Vdata+Vint-Vth)²＝K(VSS-Vdata)²；

k is a constant related to process design;

In fig. 14A-14D, the circles indicate that the respective transistors are on.

The above three specific embodiments of the pixel circuit according to the present invention and the conventional pixel circuit were simulated as follows.

The first embodiment of the pixel circuit of the present invention is compared with the conventional pixel circuit in an analog manner as follows:

when Vdata is equal to-2V, in the first embodiment of the pixel circuit according to the present invention, the corresponding relationship between the voltage Vp at the protection terminal p and the time t is shown in fig. 15A; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 15B;

when Vdata is equal to-1.5V, in the first embodiment of the pixel circuit according to the present invention, the correspondence between the voltage Vp at the protection terminal p and the time t is as shown in fig. 15C; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 15D;

when Vdata is equal to-1V, in the first embodiment of the pixel circuit according to the present invention, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 15E; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 15F.

A simulation comparison of the second embodiment of the pixel circuit of the present invention with the conventional pixel circuit is as follows:

when Vdata is equal to-2V, in the second embodiment of the pixel circuit according to the present invention, the corresponding relationship between the voltage Vp of the protection terminal p and the time t is shown in fig. 16A; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 16B;

when Vdata is equal to-1.5V, in the second embodiment of the pixel circuit according to the present invention, the corresponding relationship between the voltage Vp at the protection terminal p and the time t is shown in fig. 16C; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 16D;

when Vdata is equal to-1V, in the second embodiment of the pixel circuit according to the present invention, the corresponding relationship between the voltage Vp of the protection terminal p and the time t is shown in fig. 16E; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 16F.

The third embodiment of the pixel circuit of the present invention is compared with the conventional pixel circuit in an analog manner as follows:

when Vdata is equal to 5V, in the third embodiment of the pixel circuit according to the invention, the corresponding relationship between the voltage Vp of the protection terminal p and the time t is shown in fig. 17A; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 17B;

when Vdata is equal to 6V, in the third embodiment of the pixel circuit according to the invention, the corresponding relationship between the voltage Vp of the protection terminal p and the time t is shown in fig. 17C; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 17D;

when Vdata is equal to 7V, in the third embodiment of the pixel circuit according to the invention, the corresponding relationship between the voltage Vp of the protection terminal p and the time t is shown in fig. 17E; in the conventional pixel circuit, the correspondence between the voltage Vp of the protection terminal p and the time t is as shown in fig. 17F.

The pixel driving method according to the embodiment of the present invention is used for driving the pixel circuit, and includes:

the protection circuit controls the potential of the protection end in a light emitting stage when the light emitting control circuit starts to control the communication between the first end of the light emitting control circuit and the second end of the light emitting control circuit, so that the absolute value of the difference between the potential of the protection end and the potential of the control end of the light emitting control circuit is smaller than a preset difference.

In the pixel driving method according to the embodiment of the present invention, in a light emitting stage, when the light emission control circuit starts to control the connection between the first terminal of the light emission control circuit and the second terminal of the light emission control circuit, the potential of the protection terminal is controlled by the protection circuit, so that an absolute value of a difference between the potential of the protection terminal and the potential of the control terminal of the light emission control circuit is smaller than a predetermined difference, and a light emission control transistor included in the light emission control circuit is prevented from being broken down at the moment of starting the light emitting stage.

The display device provided by the embodiment of the invention comprises the pixel circuit.

The display device provided by the embodiment of the invention can be any product or component with a display function, such as a mobile phone, a tablet personal computer, a television, a display, a notebook computer, a digital photo frame, a navigator and the like.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A pixel circuit includes a light emitting element, a drive circuit, a light emission control circuit, and a protection circuit,

the protection circuit is electrically connected with the protection end;

2. The pixel circuit according to claim 1, wherein when a first terminal of the light emission control circuit is electrically connected to a second terminal of the driving circuit, a second terminal of the light emission control circuit is electrically connected to a first terminal of the light emitting element, a second terminal of the light emitting element is electrically connected to a cathode voltage terminal, and the protection terminal is electrically connected to the second terminal of the light emission control circuit, the protection circuit includes a protection transistor;

the protection transistor is a p-type transistor.

3. The pixel circuit according to claim 1, wherein when a second terminal of the driving circuit is electrically connected to a first terminal of the light emitting element, a first terminal of the light emission control circuit is electrically connected to a second terminal of the light emitting element, a second terminal of the light emission control circuit is electrically connected to the cathode voltage terminal, and the protection terminal is electrically connected to the first terminal of the light emission control circuit, the protection circuit includes a protection transistor;

the protection transistor is an n-type transistor.

4. The pixel circuit according to claim 1, wherein the drive circuit includes a drive transistor, and the emission control circuit includes an emission control transistor;

5. The pixel circuit according to any of claims 1 to 4, further comprising a storage capacitor, a data writing circuit, a compensation control circuit, and an initialization circuit, wherein,

6. The pixel circuit according to claim 5, further comprising a voltage control circuit;

7. The pixel circuit according to claim 5, wherein the data writing circuit includes a data writing transistor, the compensation control circuit includes a compensation control transistor, and the initialization circuit includes an initialization transistor;

8. The pixel circuit according to claim 6, wherein the voltage control circuit comprises a voltage control transistor;

9. The pixel circuit according to any one of claims 1 to 4, further comprising a first storage capacitor, a second storage capacitor, a data writing circuit, and a compensation control circuit;

10. The pixel circuit according to claim 9, wherein the data writing circuit includes a data writing transistor;

11. A pixel driving method for driving the pixel circuit according to any one of claims 1 to 10, the pixel driving method comprising:

12. A display device comprising the pixel circuit according to any one of claims 1 to 10.