Pixel circuit, driving method thereof and display device

Abstract

The application provides a pixel circuit, a driving method thereof and a display device. The pixel circuit comprises a drain current compensation module. The drain current compensation module is configured to output a drain current compensation voltage to a gate of a driving transistor in a light-emitting control stage of the pixel circuit, so as to control a potential change of the gate of the driving transistor to be opposite to a potential change caused by a drain current at the gate of the driving transistor. It can be seen that, according to the technical scheme, the gate of the driving transistor is voltage compensated by the drain current compensation module in the light-emitting control stage, so as to compensate the potential change caused by the drain current at the gate of the driving transistor, ensure high stability of the potential at the gate of the driving transistor, and further ensure high stability of a driving current generated by the driving transistor, and improve flicker problems of the display device when displaying a picture.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, more particularly, to a pixel circuit, a driving method thereof and a display device. BACKGROUND

[0002] With the development of display technology, the application of display devices is more and more common, and has gradually been applied to people's daily work and life. Among them, the OLED (Organic Light-Emitting Diode) display device has become the mainstream trend of display panels due to its high contrast, thin thickness, wide viewing angle, fast response speed, wide temperature range, simple structure and process, and other excellent characteristics.

[0003] The frame area of the OLED display device includes a driving circuit, and the display area of the display device includes a plurality of pixel units, each of which includes a pixel circuit and a light emitting element electrically connected to the pixel circuit. The pixel circuit is electrically connected to the driving circuit at the frame area, and the driving circuit provides an enable signal and the like to the pixel circuit to control the pixel circuit to provide a driving current to the light emitting element. However, due to the existence of leakage current in the pixel circuit in the current display device, the driving current output by the pixel circuit is unstable, which affects the luminous brightness of the light emitting element. In particular, with the application of variable frequency driving technology in the display device, the leakage current problem of the pixel circuit will cause the display device to flicker when displaying a picture, affecting the user experience. SUMMARY

[0004] Therefore, the present application provides a pixel circuit, a driving method thereof and a display device, which effectively solve the existing technical problems, compensate for the potential change caused by the leakage current at the gate of the driving transistor, ensure the stability of the potential at the gate of the driving transistor, and further improve the stability of the driving current generated by the driving transistor, thereby improving the flicker problem of the display device when displaying a picture.

[0005] To achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows:

[0006] A pixel circuit, comprising:

[0007] a driving transistor, the driving transistor being configured to generate a driving signal;

[0008] a first reset module, the first reset module being configured to transmit a first reset voltage to the gate of the driving transistor in response to a first reset control signal in a reset phase of the pixel circuit;

[0009] a threshold compensation module, configured to electrically connect the gate of the driving transistor and the output terminal of the driving transistor in a data writing stage of the pixel circuit in response to a threshold compensation control signal;

[0010] and a leakage current compensation module, configured to output a leakage current compensation voltage to the gate of the driving transistor in a light emitting control stage of the pixel circuit to control a potential change of the gate of the driving transistor, which is opposite to a potential change caused by a leakage current at the gate of the driving transistor.

[0011] Correspondingly, the application further provides a driving method of a pixel circuit, configured to drive the pixel circuit, and the driving method comprises:

[0012] In the light emitting control stage of the pixel circuit, the leakage current compensation module outputs a leakage current compensation voltage to the gate of the driving transistor to control a potential change of the gate of the driving transistor, which is opposite to a potential change caused by a leakage current at the gate of the driving transistor. 17. The driving method of the pixel circuit according to claim 16, wherein the driving method comprises a reset stage, a data writing stage and a light emitting control stage performed in sequence.

[0013] In the reset stage, the first reset control signal enters an enabled stage to control the first reset module to transmit the first reset voltage to the gate of the driving transistor.

[0014] In the data writing stage, the threshold compensation control signal enters an enabled stage to control the threshold compensation module to electrically connect the gate of the driving transistor and the output terminal of the driving transistor.

[0015] In the light emitting control stage, the driving transistor generates the driving signal, and at the same time, the leakage current compensation module outputs a leakage current compensation voltage to the gate of the driving transistor.

[0016] Correspondingly, the application further provides a display device comprising the pixel circuit.

[0017] Compared with the prior art, the technical solution provided by the application has at least the following advantages:

[0018] This invention provides a pixel circuit, its driving method, and a display device. The pixel circuit includes a leakage current compensation module, which outputs a leakage current compensation voltage to the gate of the driving transistor during the light-emitting control phase of the pixel circuit. This controls the potential change at the gate of the driving transistor to be opposite to the potential change caused by leakage current at the gate. Therefore, the technical solution provided by this invention compensates for the voltage change at the gate of the driving transistor during the light-emitting control phase by using the leakage current compensation module. This compensates for the potential change caused by leakage current at the gate of the driving transistor, ensuring high stability of the potential at the gate of the driving transistor. Consequently, it ensures high stability of the driving current generated by the driving transistor, improving the flicker problem when the display device shows an image. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a pixel circuit provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of another pixel circuit structure provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of another pixel circuit provided in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of another pixel circuit provided in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of another pixel circuit provided in an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of another pixel circuit provided in an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of another pixel circuit provided in an embodiment of the present invention;

[0027] Figure 8 This is a schematic diagram of another pixel circuit provided in an embodiment of the present invention;

[0028] Figure 9 This is a schematic diagram of another pixel circuit provided in an embodiment of the present invention;

[0029] Figure 10 A structure diagram of another pixel circuit provided by an embodiment of the present application is shown in FIG. 6;

[0030] Figure 11 A timing diagram provided by an embodiment of the present application is shown in FIG. 7;

[0031] Figure 12 A structure diagram of another pixel circuit provided by an embodiment of the present application is shown in FIG. 8;

[0032] Figure 13 A structure diagram of another pixel circuit provided by an embodiment of the present application is shown in FIG. 9;

[0033] Figure 14 A structure diagram of a display device provided by an embodiment of the present application is shown in FIG. 10. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0035] As described in the background, the frame area of the OLED display device includes a driving circuit, and the display area of the display device includes a plurality of pixel units, each of which includes a pixel circuit and a light emitting element electrically connected to the pixel circuit, wherein the pixel circuit is electrically connected to the driving circuit at the frame area, and the driving circuit provides an enable signal and the like to the pixel circuit to control the pixel circuit to provide a driving current to the light emitting element. However, due to the existence of the leakage current in the pixel circuit in the current display device, the driving current output by the pixel circuit is unstable, which affects the luminance of the light emitting element. In particular, with the application of variable frequency driving technology in the display device, the leakage current problem of the pixel circuit will cause the display device to flicker when displaying a picture, affecting the user experience.

[0036] Therefore, the embodiments of the present application provide a pixel circuit, a driving method thereof and a display device, which effectively solve the existing technical problems, compensate for the potential change caused by the leakage current at the gate of the driving transistor, ensure the stability of the potential at the gate of the driving transistor, and further make the driving current generated by the driving transistor stable, thereby improving the flicker problem of the display device when displaying a picture.

[0037] To achieve the above object, the technical solutions provided by the embodiments of the present application are as follows, which are specifically combined with Figures 1 to 14 The technical solutions provided by the embodiments of the present application are described in detail.

[0038] Reference Figure 1 As shown in the structure diagram of a pixel circuit provided by the embodiment of the present application, the pixel circuit comprises:

[0039] A driving transistor M0 is configured to generate a driving signal.

[0040] A first reset module 100 is configured to transmit a first reset voltage Vf1 to the gate of the driving transistor M0 in response to a first reset control signal Sf1 in a reset stage of the pixel circuit.

[0041] A threshold compensation module 200 is configured to electrically connect the gate of the driving transistor M0 with the output terminal of the driving transistor M0 in response to a threshold compensation control signal Sy in a data writing stage of the pixel circuit.

[0042] In addition, a drain current compensation module 300 is configured to output a drain current compensation voltage to the gate of the driving transistor M0 in a light-emitting control stage of the pixel circuit, so as to control the potential change of the gate of the driving transistor M0, which is opposite to the potential change caused by the drain current when the gate of the driving transistor M0 is in the light-emitting control stage.

[0043] From the above, it can be seen that the technical scheme provided by the embodiment of the present application compensates the gate of the driving transistor by the drain current compensation module in the light-emitting control stage, so as to compensate the potential change caused by the drain current at the gate of the driving transistor, thereby ensuring the stability of the potential at the gate of the driving transistor, and further ensuring the stability of the driving current generated by the driving transistor, and improving the flicker problem of the display device when displaying a picture.

[0044] In an embodiment of the present application, the driving transistor provided by the present application can be a P-type transistor or an N-type transistor, which is not specifically limited by the present application. It can be understood that the transistor connected to the gate of the driving transistor will cause the problem of drain current of the driving transistor, and thus the potential of the gate of the driving transistor will change. In the light-emitting control stage of the pixel circuit, the data voltage has been written to the gate of the driving transistor, and the drain current at the gate of the driving transistor will cause the potential to decrease. For this reason, the drain current compensation module provided by the embodiment of the present application outputs a drain current compensation voltage to raise the potential of the gate of the driving transistor for compensation, thereby ensuring the accuracy of the driving current generated by the driving transistor, and further ensuring the stability of the driving current generated by the driving transistor, and improving the flicker problem of the display device when displaying a picture.

[0045] It should be noted that the embodiment of the present application does not specifically limit the value of the drain current compensation voltage, which needs to be specifically analyzed and calculated according to the actual application.

[0046] In one embodiment of the present invention, the pixel circuit provided by the present invention can not only compensate for leakage current at the gate of the driving transistor during the light emission control stage, but also compensate for leakage current at the gate of the driving transistor during the reset stage, thereby improving the reset effect. Figure 2 The diagram shown is a schematic diagram of another pixel circuit provided in an embodiment of the present invention. The pixel circuit further includes an auxiliary reset module 400, which is used to output an auxiliary reset voltage to the gate of the driving transistor M0 during the reset phase, so as to control the potential change of the gate of the driving transistor M0, which is opposite to the potential change caused by leakage current when the gate of the driving transistor M0 is in the reset phase.

[0047] Understandably, during the pixel circuit's reset phase, the first reset module transmits a first reset voltage to the gate of the driving transistor for reset. However, leakage current at the gate of the driving transistor can cause variations in the first reset voltage, leading to incomplete reset. Therefore, an auxiliary reset module outputs an auxiliary reset voltage to the gate of the driving transistor, controlling the gate's potential to be opposite to the potential change caused by leakage current. This compensates for the potential at the driving transistor's gate, improving the reset effect. If the driving transistor is a P-type transistor, the first reset voltage is negative. Leakage current at the gate of the driving transistor can cause the first reset voltage to increase numerically. Compensation with the auxiliary reset voltage reduces the first reset voltage at the driving transistor's gate, ensuring a high reset effect.

[0048] Similarly, when the driving transistor is an N-type transistor, the first reset voltage is a positive voltage. The leakage current at the gate of the driving transistor will cause the first reset voltage to decrease in value. By compensating for the auxiliary reset voltage, the first reset voltage at the gate of the driving transistor is increased, ensuring a high reset effect.

[0049] It should be noted that the embodiments of the present invention do not impose specific limitations on the magnitude of the auxiliary reset voltage, which needs to be analyzed and calculated based on the actual application.

[0050] like Figure 3 The diagram shown is a schematic diagram of another pixel circuit provided in an embodiment of the present invention. The auxiliary reset module 400 provided in this embodiment of the present invention can reuse the leakage current compensation module 300. The leakage current compensation module 300 outputs the auxiliary reset voltage during the reset phase and outputs the leakage current compensation voltage during the light emission control phase.

[0051] It can be understood that the auxiliary reset module provided by the embodiment of the present application works in the reset stage, and the leakage current compensation module works in the light-emitting control stage. Since the working periods are different, the auxiliary reset module can reuse the leakage current compensation module. The reused leakage current compensation module works in time, that is, outputs a reset voltage to the gate of the driving transistor in the reset stage, and outputs a leakage current compensation voltage to the gate of the driving transistor in the light-emitting control stage, and is floating in the data writing stage. In this way, the compensation functions of the reset stage and the light-emitting control stage are completed, the number of module components of the pixel circuit is reduced, and the composition structure of the pixel circuit is simplified.

[0052] In an embodiment of the present application, the leakage current compensation module provided by the present application can change the voltage at the gate of the driving transistor through a capacitor. Referring to Figure 4 As shown in FIG. 3, it is another structure schematic diagram of the pixel circuit provided by the embodiment of the present application, wherein the leakage current compensation module 300 comprises a compensation capacitor Cb and a compensation voltage terminal Vb; the first plate of the compensation capacitor Cb is electrically connected with the gate of the driving transistor M0, and the second plate of the compensation capacitor Cb is electrically connected with the compensation voltage terminal Vb.

[0053] It can be understood that the leakage current compensation module provided by the embodiment of the present application couples the voltage output by the compensation voltage terminal to the gate of the driving transistor through the coupling effect of the compensation capacitor, so as to compensate the voltage at the gate of the driving transistor. When the driving transistor is a P-type transistor, and the auxiliary reset module reuses the leakage current compensation module, the compensation voltage terminal outputs a high-level voltage in the reset stage, thereby compensating the increase of the first reset voltage at the gate of the driving transistor caused by the leakage current, so that the first reset voltage at the gate of the driving transistor is reduced, and the reset effect is ensured; and the compensation voltage terminal outputs a low-level voltage in the light-emitting control stage, thereby compensating the decrease of the data voltage included at the gate of the driving transistor caused by the leakage current, so that the data voltage included at the gate of the driving transistor is increased, the driving current generated by the driving transistor is accurate and stable, the light-emitting effect of the light-emitting element is improved, and the display effect of the display device is improved.

[0054] Similarly, when the driving transistor is an N-type transistor, and the auxiliary reset module reuses the leakage current compensation module, the voltage output by the compensation voltage terminal and the compensation capacitor are coupled to compensate the first reset voltage at the gate of the driving transistor in the reset stage, and to compensate the data voltage included at the gate of the driving transistor in the light-emitting control stage, thereby improving the display effect of the display device.

[0055] It should be noted that the voltage value outputted by the compensation voltage terminal is not specifically limited, and needs to be specifically analyzed and calculated according to actual application. In addition, the compensation voltage terminal can be an independent voltage terminal, or can be integrated into the driving chip of the display device, and the present application does not make specific limitations.

[0056] Further, the compensation voltage terminal and the compensation capacitor can be connected with a controllable switch. The controllable switch can be turned on when the leakage current compensation module works, and turned off when the leakage current compensation module is floating. This can avoid the situation that the compensation capacitor couples extra voltage to the gate of the driving transistor when the leakage current compensation module is floating due to the compensation voltage terminal not outputting voltage in time. Figure 5 As shown in FIG. 6, which is a structure schematic diagram of another pixel circuit provided by the present application, the leakage current compensation module 300 further comprises a compensation transistor Mb electrically connected between the compensation capacitor Cb and the compensation voltage terminal Vb. The first end of the compensation transistor Mb is electrically connected with the compensation voltage terminal Vb, the second end of the compensation transistor Mb is electrically connected with the second plate of the compensation capacitor Cb, and the gate of the compensation transistor Mb is connected with a compensation control signal Sb.

[0057] It can be understood that when the auxiliary reset module multiplexes the leakage current compensation module, the compensation transistor provided by the present application is turned on in response to the compensation control signal in the reset stage, turned on in response to the compensation control signal in the light-emitting control stage, and cut off in response to the compensation control signal in the data writing stage. Alternatively, when the auxiliary reset module does not multiplex the leakage current compensation module, and the conduction type of the compensation transistor is the same as that of the light-emitting control transistor in the light-emitting control module, the compensation control signal can multiplex the light-emitting control signal, thereby reducing the number of control signal terminals and simplifying the pixel circuit.

[0058] In an embodiment of the present application, the voltage value outputted by the compensation voltage terminal can be fixed, i.e., the voltage value outputted by the compensation voltage terminal is the same in the first light-emitting control stage to the Nth light-emitting control stage of the pixel circuit, and N is an integer greater than or equal to 2. It can be understood that during the display process from power-on to power-off of the display device, the pixel circuit performs N light-emitting control stages, and the voltage value outputted by the compensation voltage terminal in each light-emitting control stage is the same, thereby avoiding the problem of increased power consumption caused by the change of the voltage value outputted by the compensation voltage terminal. Correspondingly, when the auxiliary reset module multiplexes the leakage current compensation module, the voltage value outputted by the compensation voltage terminal in each reset stage can also be the same, and the present application does not make specific limitations.

[0059] Alternatively, the voltage value output by the compensation voltage terminal can be variable, that is, in the first light-emitting control stage to the Nth light-emitting control stage of the pixel circuit, the voltage value output by the compensation voltage terminal in the ith light-emitting control stage is the ith voltage value, where the ith voltage value is determined according to the voltage at the gate of the driving transistor in the ith light-emitting control stage. It can be understood that, in the display process from power-on to power-off of the display device, the pixel circuit performs N light-emitting control stages, and the voltage value output by the compensation voltage terminal in each light-emitting control stage is determined according to the voltage at the gate of the driving transistor; that is, the voltage at the gate of the driving transistor changes in the light-emitting control stage, and the compensation voltage terminal outputs a corresponding voltage, and then the change of the voltage at the gate of the driving transistor is compensated by the coupling of the compensation capacitor, so as to more accurately compensate the voltage at the gate of the driving transistor. Correspondingly, when the auxiliary reset module is multiplexed with the leakage current compensation module, the voltage value output by the compensation voltage terminal in each reset stage can also be determined according to the voltage at the gate of the driving transistor, which is not limited by the present application.

[0060] In order to monitor the voltage at the gate of the driving transistor to determine the size of the voltage value output by the compensation voltage terminal, the pixel circuit provided by the embodiment of the present application further comprises a voltage monitoring module. As shown in Figure 6 Fig. 6 is a structural schematic diagram of another pixel circuit provided by the embodiment of the present application, where the pixel circuit further comprises a voltage monitoring module 500 electrically connected to the gate of the driving transistor M0 and the compensation voltage terminal Vb, the voltage monitoring module 500 is used to monitor the voltage at the gate of the driving transistor M0 in the light-emitting control stage, and send the monitored voltage to the compensation voltage terminal Vb, and the compensation voltage terminal Vb outputs a corresponding voltage to the compensation capacitor Cb according to the monitored voltage.

[0061] It can be understood that the voltage monitoring module is electrically connected to the gate of the driving transistor, and thus can monitor the voltage at the gate of the driving transistor; and the voltage monitoring module is also electrically connected to the compensation voltage terminal, and the voltage monitoring module sends the monitored voltage to the compensation voltage terminal, so that the compensation voltage terminal can determine the voltage value to be output according to the monitored voltage. Correspondingly, when the auxiliary reset module is multiplexed with the leakage current compensation module, the voltage monitoring module can also monitor the voltage at the gate of the driving transistor in the reset stage, and send the monitored voltage to the compensation voltage terminal, so that the compensation voltage terminal can determine the voltage value to be output according to the monitored voltage, to compensate the voltage at the gate of the driving transistor in the reset stage.

[0062] In an embodiment of the present application, the display device provided by the present application comprises a plurality of pixel circuits, all of which comprise a voltage monitoring module which can be multiplexed into one voltage monitoring module, thereby effectively reducing the circuit composition of the display device and increasing the wiring area. Moreover, the voltage monitoring module provided by the embodiment of the present application can be an independent circuit structure of the pixel circuit, and can also be integrated into the driving chip of the display device, and the present application does not make specific limitations in this regard.

[0063] Reference Figure 7 As shown in FIG. 6, which is a structural schematic diagram of another pixel circuit provided by the embodiment of the present application, the first reset module 100 provided by the embodiment of the present application comprises a first reset transistor Mf1, the first end of the first reset transistor Mf1 is connected to the first reset voltage Vf1, the gate of the first reset transistor Mf1 is connected to the first reset control signal Sf1, and the second end of the first reset transistor Mf1 is electrically connected to the gate of the driving transistor M0.

[0064] Moreover, the threshold compensation module 200 comprises a threshold compensation transistor My, the first end of the threshold compensation transistor My is electrically connected to the gate of the driving transistor M0, the second end of the threshold compensation transistor My is electrically connected to the output end of the driving transistor M0, and the gate of the threshold compensation transistor My is connected to the threshold compensation control signal Sy.

[0065] It can be understood that, in the reset phase, the first reset control signal enables the first reset transistor to be turned on, and the first reset transistor transmits the first reset voltage to the gate of the driving transistor for resetting. In the data writing phase, the threshold compensation control signal enables the threshold compensation transistor to be turned on, and the threshold compensation transistor connects the gate and the output end of the driving transistor. Optionally, the first reset transistor and the threshold compensation transistor provided by the embodiment of the present application can be N-type transistors or P-type transistors, and the present application does not make specific limitations in this regard.

[0066] As Figure 8 As shown in FIG. 7, which is a structural schematic diagram of another pixel circuit provided by the embodiment of the present application, the first reset transistor Mf1 and / or the threshold compensation transistor My provided by the embodiment of the present application can be a double-gate transistor, thereby improving the response speed of the reset module and the threshold compensation module and improving the performance of the pixel circuit.

[0067] Moreover, the first reset transistor and / or the threshold compensation transistor provided by the embodiment of the present application can be an oxide transistor, thereby being able to reduce the influence of the first reset transistor and the threshold compensation transistor on the gate current of the driving transistor and ensuring the high performance of the pixel circuit.

[0068] AsFigure 9 As shown in FIG. 7, which is a structural schematic diagram of still another pixel circuit provided by an embodiment of the present application, the pixel circuit provided by the embodiment of the present application comprises a data writing module 600, a light emitting control module 700 and a storage capacitor Cst; the data writing module 600 is configured to transmit a data voltage Vdata to an input terminal of a driving transistor M0 in response to a data writing control signal Sx in the data writing stage; the light emitting control module 700 is configured to output a driving signal generated by the driving transistor M0 to a light emitting element 800 in response to a light emitting control signal Sg in the light emitting control stage, and the light emitting element 800 emits light in response to the driving signal; a first plate of the storage capacitor Cst is connected to a power supply voltage Pvdd, and a second plate of the storage capacitor Cst is electrically connected to a gate of the driving transistor M0.

[0069] As shown in FIG. 7, which is a structural schematic diagram of still another pixel circuit provided by an embodiment of the present application, the pixel circuit provided by the embodiment of the present application comprises a data writing module 600, a light emitting control module 700 and a storage capacitor Cst; the data writing module 600 is configured to transmit a data voltage Vdata to an input terminal of a driving transistor M0 in response to a data writing control signal Sx in the data writing stage; the light emitting control module 700 is configured to output a driving signal generated by the driving transistor M0 to a light emitting element 800 in response to a light emitting control signal Sg in the light emitting control stage, and the light emitting element 800 emits light in response to the driving signal; a first plate of the storage capacitor Cst is connected to a power supply voltage Pvdd, and a second plate of the storage capacitor Cst is electrically connected to a gate of the driving transistor M0. Figure 10 As shown in FIG. 7, which is a structural schematic diagram of still another pixel circuit provided by an embodiment of the present application, the pixel circuit provided by the embodiment of the present application comprises a data writing module 600, a light emitting control module 700 and a storage capacitor Cst; the data writing module 600 is configured to transmit a data voltage Vdata to an input terminal of a driving transistor M0 in response to a data writing control signal Sx in the data writing stage; the light emitting control module 700 is configured to output a driving signal generated by the driving transistor M0 to a light emitting element 800 in response to a light emitting control signal Sg in the light emitting control stage, and the light emitting element 800 emits light in response to the driving signal; a first plate of the storage capacitor Cst is connected to a power supply voltage Pvdd, and a second plate of the storage capacitor Cst is electrically connected to a gate of the driving transistor M0.

[0070] The light emitting control module 700 comprises a first light emitting control transistor Mg1 and a second light emitting control transistor Mg2; a first end of the first light emitting control transistor Mg1 is connected to the power supply voltage Pvdd, a second end of the first light emitting control transistor Mg1 is electrically connected to the input terminal of the driving transistor M0, and a gate of the first light emitting control transistor Mg1 is connected to the light emitting control signal Sg; a first end of the second light emitting control transistor Mg2 is electrically connected to an output terminal of the driving transistor M0, a second end of the second light emitting control transistor Mg2 is electrically connected to the light emitting element 800, and a gate of the second light emitting control transistor Mg2 is connected to the light emitting control signal Sg.

[0071] In an embodiment of the present application, when the data writing transistor and the threshold compensation transistor provided by the present application are of the same conduction type, the data writing control signal and the threshold compensation control signal can be the same control signal, so as to reduce the number of control signal terminals and simplify the wiring of the pixel circuit.

[0072] In addition, the capacitance of the compensation capacitor provided by the embodiment of the present application can be smaller than the capacitance of the storage capacitor, so as to improve the charge and discharge efficiency of the compensation capacitor and improve the compensation efficiency of the voltage at the gate of the driving transistor.

[0073] The pixel circuit provided by the embodiment of the present application is described in more detail below in combination with a timing diagram. It should be noted that the description below is given by taking an example in which all the transistors included in the pixel circuit are P-type transistors and the multiplexing of the auxiliary reset module and the leakage compensation module is taken as an example. The working process of the pixel circuit provided by the embodiment of the present application includes a reset phase T1, a data writing phase T2 and a light emitting control phase T3 in sequence in combination with the timing diagram shown in Figure 10 and Figure 11 . Figure 11 The working process of the pixel circuit provided by the embodiment of the present application includes a reset phase T1, a data writing phase T2 and a light emitting control phase T3 in sequence in combination with the timing diagram shown in

[0074] In the reset phase T1, the first reset control signal Sf1 and the compensation control signal Sb are low, the first reset transistor Mf1 is turned on to transmit the first reset voltage Vf1 to the gate of the driving transistor M0; the voltage monitoring module 500 monitors the voltage at the driving transistor M0 and transmits the monitored voltage to the compensation voltage terminal Vb; the compensation voltage terminal Vb outputs a corresponding voltage value according to the monitored voltage, the compensation transistor Mb transmits the voltage to the compensation capacitor Cb, and the auxiliary reset voltage is output to the gate of the driving transistor M0 through the coupling effect of the compensation capacitor Cb for compensation, thereby improving the reset effect at the gate of the driving transistor. At this time, the threshold compensation control signal Sy, the data writing control signal Sx and the light emitting control signal Sg are high and non-enabled.

[0075] In the data writing phase T2, the threshold compensation control signal Sy and the data writing control signal Sx are low, the threshold compensation transistor My is turned on to connect the gate of the driving transistor M0 and its output terminal in communication; the data writing transistor Mx is turned on to transmit the data voltage Vdata to the input terminal of the driving transistor M0, and the data voltage Vdata is written to the gate of the driving transistor M0 after passing through the driving transistor M0 and the threshold compensation transistor My. At this time, the first reset control signal Sf1, the compensation control signal Sb and the light emitting control signal Sg are high and non-enabled.

[0076] During the light-emitting control phase T3, the light-emitting control signal Sg and the compensation control signal Sb are enabled at low levels. The first light-emitting control transistor Mg1 and the second light-emitting control transistor Mg2 are turned on, transmitting the driving current generated by the driving transistor M0 to the light-emitting element 800. Simultaneously, the voltage monitoring module 500 monitors the voltage at the driving transistor M0 and transmits the monitored voltage to the compensation voltage terminal Vb. The compensation voltage terminal Vb outputs a corresponding voltage value based on the monitored voltage. The compensation transistor Mb transmits the voltage to the compensation capacitor Cb. Through the coupling effect of the compensation capacitor Cb, the leakage current compensation voltage is output to the gate of the driving transistor M0 for compensation, ensuring high accuracy and stability of the data voltage at the gate of the driving transistor M0, thereby improving the accuracy and stability of the driving current and enhancing the stability and brightness of the light-emitting element. At this time, the first reset control signal Sf1, the threshold compensation control signal Sy, and the data write control signal Sx are disabled at high levels.

[0077] Furthermore, the pixel circuit provided in this embodiment of the invention can also reset the light-emitting element. For example... Figure 12 The diagram shown is a schematic diagram of another pixel circuit provided in an embodiment of the present invention. The pixel circuit further includes a second reset module 900. The second reset module 900 is used to respond to the second reset control signal Sf2 during the reset phase and transmit the second reset voltage Vf2 to the connection terminal of the light-emitting control module 700 and the light-emitting element 800.

[0078] It is understood that the second reset module provided in this embodiment of the invention can reset the connection end between the light-emitting element and the light-emitting control module during the reset stage, which can prevent the light-emitting element from not being dark in the dark state.

[0079] like Figure 13 The diagram shows a schematic of another pixel circuit provided in an embodiment of the present invention. The second reset module 900 provided in this embodiment of the present invention includes a second reset transistor Mf2. The first terminal of the second reset transistor Mf2 is connected to the second reset voltage Vf2. The second terminal of the second reset transistor Mf2 is electrically connected to the connection terminal of the light emission control module 700 and the light emission element 800. The gate of the second reset module Mf2 is connected to the second reset control signal Sf2.

[0080] Optionally, when the second reset transistor and the first reset transistor provided in the embodiments of the present invention have the same conduction type, since both the second reset transistor and the first reset transistor are turned on during the reset phase, the second reset control signal and the first reset control signal can be the same control signal; and the first reset voltage and the second reset voltage can be output from the same voltage terminal, thereby reducing the number of signal terminals and simplifying the wiring of the pixel circuit.

[0081] Correspondingly, the application also provides a driving method of a pixel circuit, used for driving the pixel circuit provided by any one of the above embodiments, and the driving method comprises the following steps of:

[0082] In the light-emitting control stage of the pixel circuit, the drain current compensation module outputs a drain current compensation voltage to the gate of the driving transistor to control the potential change of the gate of the driving transistor, which is opposite to the potential change caused by the drain current at the gate of the driving transistor.

[0083] It can be understood that, in the light-emitting control stage, the technical solution provided by the embodiment of the application compensates the voltage of the gate of the driving transistor through the drain current compensation module to compensate the potential change caused by the drain current at the gate of the driving transistor, thereby ensuring the stability of the potential at the gate of the driving transistor, and further ensuring the stability of the driving current generated by the driving transistor, and improving the flicker problem of the display device when displaying a picture.

[0084] Specifically, the driving method provided by the embodiment of the application comprises a reset stage, a data writing stage and a light-emitting control stage which are sequentially performed.

[0085] In the reset stage, the first reset control signal enters an enabled stage to control the first reset module to transmit the first reset voltage to the gate of the driving transistor.

[0086] In the data writing stage, the threshold compensation control signal enters an enabled stage to control the threshold compensation module to electrically connect the gate of the driving transistor and the output end of the transistor.

[0087] In the light-emitting control stage, the driving transistor generates the driving signal, and at the same time, the drain current compensation module outputs a drain current compensation voltage to the gate of the driving transistor.

[0088] It should be noted that the driving method provided by the embodiment of the application can be combined with the above Figure 10 and Figure 11 the description of the corresponding reset stage, data writing stage and light-emitting control stage, and the application will not make redundant description.

[0089] In an embodiment of the application, the pixel circuit provided by the application further comprises an auxiliary reset module, wherein in the reset stage, the auxiliary reset module is used to output an auxiliary reset voltage to the gate of the driving transistor to control the potential change of the gate of the driving transistor, which is opposite to the potential change caused by the drain current at the gate of the driving transistor. Optionally, the auxiliary reset module provided by the embodiment of the application can be reused as the drain current compensation module, and therefore, in the reset stage, the drain current compensation module can output an auxiliary reset voltage to the gate of the driving transistor to improve the reset effect.

[0090] Correspondingly, the application further provides a display device, which comprises the pixel circuit.

[0091] Reference Figure 14 As shown in the figure, the display device provided by the embodiment of the application is a structure schematic diagram of a display device, wherein the display device 1000 provided by the embodiment of the application can be a mobile terminal, and the display device 1000 comprises the pixel circuit provided by any one of the above-mentioned embodiments.

[0092] It should be noted that the display device provided by the embodiment of the application can also be a notebook computer, a tablet computer, a computer, a wearable device, etc., and the application does not make specific limitations on this.

[0093] The embodiment of the application provides a pixel circuit, a driving method thereof and a display device. The pixel circuit comprises a drain current compensation module. The drain current compensation module is configured to output a drain current compensation voltage to a gate of the driving transistor in a light-emitting control phase of the pixel circuit, so as to control a potential change of the gate of the driving transistor to be opposite to a potential change caused by a drain current at the gate of the driving transistor. It can be seen that, in the light-emitting control phase, the gate of the driving transistor is compensated by the drain current compensation module, so as to compensate the potential change caused by the drain current at the gate of the driving transistor, ensure the stability of the potential at the gate of the driving transistor, and further ensure the stability of the driving current generated by the driving transistor, thereby improving the flicker problem of the display device when displaying a picture.

[0094] In the description of the application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0095] In addition, the terms "first" and "second" appear only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0096] In the present application, unless specifically defined otherwise, the terms "mount", "connected", "connecting", "fixed", "linking", and the like should be construed broadly and can be either direct or indirect, and can be mechanical or electronic, and can be permanent or releasable, and can be direct or indirect, and can be internal or external, and can be mutual or one-way, unless otherwise specifically stated or limited.

[0097] In the present application, unless specifically defined otherwise, the terms "on", "under", "above", and "underneath" can be direct contact, or indirect contact through an intermediate medium. Moreover, "above", "over", and "on" can be directly above or obliquely above, or simply indicate that the first feature is higher than the second feature. "Under", "below", and "underneath" can be directly below or obliquely below, or simply indicate that the first feature is lower than the second feature.

[0098] In the present application, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" as used herein to mean that a specific feature, structure, material, or characteristic being described is included in at least one embodiment or example of the present application. The illustrative examples described herein are not meant to be limiting to a particular embodiment or example of the present application. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Moreover, the use of the terms first, second, etc. do not generally limit the scope of the application, but such terms have been used for clarity in description of the application.

[0099] Although the embodiments of the present application have been shown and described above, it is to be understood that the above embodiments are merely exemplary, and are not to be construed as limiting the present application, and that modifications, substitutions, replacements, and variations of the above embodiments can be made by those skilled in the art within the scope of the present application.

Claims

1. A pixel circuit, characterized by comprising: The pixel circuit comprises: a driving transistor for generating a driving signal; a first reset module for transmitting a first reset voltage to a gate of the driving transistor in response to a first reset control signal in a reset stage of the pixel circuit; a threshold compensation module for electrically connecting the gate of the driving transistor with an output terminal of the driving transistor in response to a threshold compensation control signal in a data writing stage of the pixel circuit; and a drain current compensation module for outputting a drain current compensation voltage to the gate of the driving transistor to control a potential change of the gate of the driving transistor opposite to a potential change caused by a drain current at the gate of the driving transistor in an emission control stage of the pixel circuit. The drain current compensation module comprises a compensation capacitor and a compensation voltage terminal; a first plate of the compensation capacitor is electrically connected with the gate of the driving transistor, and a second plate of the compensation capacitor is electrically connected with the compensation voltage terminal. In the first emission control stage to the Nth emission control stage of the pixel circuit, a voltage value output by the compensation voltage terminal in the ith emission control stage is an ith voltage value, where the ith voltage value is determined according to a voltage of the gate of the driving transistor in the ith emission control stage, and i is a positive integer not greater than N.

2. The pixel circuit of claim 1, wherein, The pixel circuit further comprises an auxiliary reset module for outputting an auxiliary reset voltage to the gate of the driving transistor to control a potential change of the gate of the driving transistor opposite to a potential change caused by a drain current at the gate of the driving transistor in the reset stage of the pixel circuit.

3. The pixel circuit of claim 2, wherein, The auxiliary reset module multiplexes the drain current compensation module, wherein the drain current compensation module outputs the auxiliary reset voltage in the reset stage and outputs the drain current compensation voltage in the emission control stage.

4. The pixel circuit of claim 1, wherein, The drain current compensation module further comprises a compensation transistor electrically connected between the compensation capacitor and the compensation voltage terminal. The first end of the compensation transistor is electrically connected with the compensation voltage terminal, the second end of the compensation transistor is electrically connected with the second plate of the compensation capacitor, and the gate of the compensation transistor is connected with a compensation control signal.

5. The pixel circuit of claim 1, wherein, In the first emission control stage to the Nth emission control stage of the pixel circuit, the voltage value output by the compensation voltage terminal each time is the same, and N is an integer greater than or equal to 2.

6. The pixel circuit of claim 1, wherein, The pixel circuit further comprises a voltage monitoring module electrically connected with the gate of the driving transistor and the compensation voltage terminal, the voltage monitoring module is configured to monitor a voltage of the gate of the driving transistor in the emission control stage and send a monitoring voltage to the compensation voltage terminal, and the compensation voltage terminal outputs a corresponding voltage to the compensation capacitor according to the monitoring voltage.

7. The pixel circuit of claim 1, wherein, The first reset module comprises a first reset transistor, a first end of the first reset transistor is connected to the first reset voltage, a gate of the first reset transistor is connected to the first reset control signal, and a second end of the first reset transistor is electrically connected to the gate of the driving transistor. The threshold compensation module comprises a threshold compensation transistor, a first end of the threshold compensation transistor is electrically connected to the gate of the driving transistor, a second end of the threshold compensation transistor is electrically connected to the output end of the driving transistor, and a gate of the threshold compensation transistor is connected to the threshold compensation control signal.

8. The pixel circuit of claim 7, wherein, The first reset transistor and / or the threshold compensation transistor is a double-gate transistor.

9. The pixel circuit of claim 7, wherein, The first reset transistor and / or the threshold compensation transistor is an oxide transistor.

10. The pixel circuit of claim 1, wherein, The pixel circuit comprises a data writing module, a light emitting control module, and a storage capacitor. The data writing module is configured to transmit a data voltage to an input end of the driving transistor in response to a data writing control signal in the data writing stage. The light emitting control module is configured to output a driving signal generated by the driving transistor to a light emitting element in response to a light emitting control signal in the light emitting control stage, and the light emitting element emits light in response to the driving signal. A first plate of the storage capacitor is connected to a power supply voltage, and a second plate of the storage capacitor is electrically connected to the gate of the driving transistor.

11. The pixel circuit of claim 10, wherein, The data writing module comprises a data writing transistor, a first end of the data writing transistor is connected to the data voltage, a second end of the data writing transistor is electrically connected to the input end of the driving transistor, and a gate of the data writing transistor is connected to the data writing control signal. The light emitting control module comprises a first light emitting control transistor and a second light emitting control transistor, a first end of the first light emitting control transistor is connected to the power supply voltage, a second end of the first light emitting control transistor is electrically connected to the input end of the driving transistor, and a gate of the first light emitting control transistor is connected to the light emitting control signal. A first end of the second light emitting control transistor is electrically connected to the output end of the driving transistor, a second end of the second light emitting control transistor is electrically connected to the light emitting element, and a gate of the second light emitting control transistor is connected to the light emitting control signal.

12. The pixel circuit of claim 10, wherein, The pixel circuit further comprises a second reset module, which is configured to transmit a second reset voltage to the light emitting control module and a connection end of the light emitting element in response to a second reset control signal in the reset stage.

13. The pixel circuit of claim 12, wherein, The second reset module comprises a second reset transistor, a first end of the second reset transistor is connected to the second reset voltage, a second end of the second reset transistor is electrically connected to the light emitting control module and the connection end of the light emitting element, and a gate of the second reset transistor is connected to the second reset control signal.

14. A driving method of a pixel circuit, characterized by, The driving method for driving the pixel circuit of any one of claims 1-13 comprises: In the light emitting control stage of the pixel circuit, the drain current compensation module outputs a drain current compensation voltage to the gate of the driving transistor to control the potential change of the gate of the driving transistor, which is opposite to the potential change caused by the drain current at the gate of the driving transistor.

15. The driving method of the pixel circuit according to claim 14, wherein The driving method comprises a reset stage, a data writing stage and a light emitting control stage performed in sequence. In the reset stage, the first reset control signal enters an enabling stage to control the first reset module to transmit the first reset voltage to the gate of the driving transistor. In the data writing stage, the threshold compensation control signal enters an enabling stage to control the threshold compensation module to electrically connect the gate of the driving transistor and the output terminal of the transistor. In the light emitting control stage, the driving transistor generates the driving signal, and meanwhile, the drain current compensation module outputs a drain current compensation voltage to the gate of the driving transistor.

16. The driving method of the pixel circuit according to claim 15, wherein The pixel circuit further comprises an auxiliary reset module, wherein in the reset stage, the auxiliary reset module is configured to output an auxiliary reset voltage to the gate of the driving transistor to control the potential change of the gate of the driving transistor, which is opposite to the potential change caused by the drain current at the gate of the driving transistor.

17. A display device comprising: The display device comprises the pixel circuit according to any one of claims 1-13.

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