Pixel circuit and driving method thereof, display device, and equipment

Abstract

The present application relates to a pixel circuit and its driving method, display device and equipment. The driving control unit provides a power signal provided by a power signal end to a first node under the control of a first control signal end, and provides a data input signal from a data signal end to the first node through a data writing unit under the control of a second control signal end, so that the driving unit outputs a driving signal to a third node under the control of the potential of the first node to drive a display light-emitting unit to emit light, and under the control of the third control signal end, the reference voltage signal of the reference voltage end is provided to the second node through a reset unit, so that the charge and discharge control unit outputs a discharge compensation signal to the third node based on the amount of electricity stored in the second storage unit under the control of a fourth control signal end, thereby achieving threshold voltage compensation, thereby solving the pixel circuit problem caused by threshold voltage changes in the existing related technology.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a pixel circuit and a driving method thereof, a display device, and equipment. Background Art

[0002] With the rapid development of display technology, active-matrix organic light-emitting diode (AMOLED) displays are becoming increasingly popular. Compared with traditional liquid crystal displays (LCDs), AMOLED displays have advantages such as wide viewing angle, high contrast, fast response time, and high brightness.

[0003] Currently, significant research is underway on AMOLED displays, focusing on reducing power consumption, weight, and complexity while increasing their pixel density, aperture ratio, and lifetime. Existing technologies typically use oxide thin-film transistors (TFTs) to implement pixel circuits in displays, primarily to reduce production costs and given their ability to offer good mobility of approximately 10 cm² / Vs and initial uniformity. Among all these oxide TFTs, amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors have garnered considerable attention due to several highly sought-after properties, including transparency, high electron mobility, good uniformity, high on-off current ratio, sharp threshold swing, and low processing temperature. Several fabrication techniques for high-performance a-IGZO thin-film transistors have also been proposed, such as using atmospheric pressure plasma jet deposition. However, threshold voltage instability under gate bias stress remains a problem in a-IGZO pixel circuits, leading to degradation of the organic light-emitting diode (OLED) current over time, thus limiting the lifetime of OLED panels. Summary of the Invention

[0004] The present application provides a pixel circuit and a driving method thereof, a display device, and an apparatus to solve the pixel circuit problem caused by the change of threshold voltage in the existing related technology.

[0005] In a first aspect, an embodiment of the present application provides a pixel circuit, comprising: a driving control unit, a data writing unit, a reset unit, a charge and discharge control unit, a driving unit, a first storage unit, a second storage unit, and a display light-emitting unit;

[0006] The driving control unit is configured to provide the power signal provided by the power signal terminal to the first node under the control of the first control signal terminal;

[0007] The data writing unit is configured to provide a data input signal from a data signal terminal to the first node under the control of a second control signal terminal;

[0008] The reset unit is configured to provide a reference voltage signal from the reference voltage terminal to a second node under the control of the third control signal terminal, wherein the second node is a node where the reset unit is connected to the second terminal of the first storage unit and the first terminal of the second storage unit, the first terminal of the first storage unit is electrically connected to the first node, and the second terminal of the second storage unit is electrically connected to the charge and discharge control unit;

[0009] The charge and discharge control unit is configured to output a discharge compensation signal to a third node based on the amount of electricity stored in the second storage unit under the control of a fourth control signal terminal, wherein the third node is a node connecting the charge and discharge control unit, the driving unit, and the display light-emitting unit;

[0010] The driving unit is configured to output a driving signal to the third node under the control of the potential of the first node, wherein the driving signal is configured to drive the display light-emitting unit to emit light.

[0011] Optionally, the drive control unit includes: a drive control transistor; the first end of the drive control transistor is electrically connected to the first end of the drive unit and the power signal end, the control end of the drive control transistor is electrically connected to the first control signal end, and the second end of the drive control transistor is electrically connected to the first node, and the first node is a node connecting the control end of the drive unit and the first end of the first storage unit and the data writing unit.

[0012] Optionally, the driving unit includes a driving transistor;

[0013] The first terminal of the driving crystal is electrically connected to the power signal terminal, the control terminal of the driving transistor is electrically connected to the first node, and the second terminal of the driving transistor is electrically connected to the third node.

[0014] Optionally, the reset unit includes: a reset transistor;

[0015] The first terminal of the reset transistor is electrically connected to the reference voltage terminal, the second terminal of the reset transistor is electrically connected to the second node, and the control terminal of the reset transistor is electrically connected to the third control signal terminal.

[0016] Optionally, the data writing unit includes a data writing transistor, the control end of the data writing transistor is electrically connected to the second control signal end, the first end of the data writing transistor is electrically connected to the data signal end, and the second end of the data writing transistor is electrically connected to the first node.

[0017] Optionally, the charge and discharge control unit includes a charge and discharge control transistor, the control end of the charge and discharge control transistor is electrically connected to the fourth control signal end, the first end of the charge and discharge control transistor is electrically connected to the second end of the second storage unit, and the second end of the charge and discharge control transistor is electrically connected to the third node.

[0018] Optionally, the first storage unit includes a first capacitor, the second storage unit includes a second capacitor, the first end of the first capacitor is electrically connected to the first node, the second end of the first capacitor and the first end of the second capacitor are both electrically connected to the second node, and the second end of the second capacitor is electrically connected to the first end of the charge and discharge control unit.

[0019] Optionally, the display light-emitting unit includes a third capacitor and a light-emitting device, the anode of the light-emitting device is electrically connected to one end of the third capacitor and the third node, and the other end of the third capacitor is electrically connected to the cathode of the light-emitting device and the reference voltage end.

[0020] In a second aspect, an embodiment of the present application provides a method for driving a pixel circuit, for driving the pixel circuit according to any one of the first aspects above, the driving method comprising:

[0021] In the reset stage, under the control of the third control signal terminal and the fourth control terminal, the reference voltage signal of the reference voltage terminal is provided to the second node, the second node being a node where the reset unit in the pixel circuit is connected to the second terminal of the first storage unit and the first terminal of the second storage unit; and under the control of the target control signal terminal, the first node of the pixel circuit is reset by a reset signal, the target control signal terminal includes the first control signal terminal and / or the second control signal terminal, the first node is a node where the driving unit in the pixel circuit is connected to the driving control unit, the first storage unit and the data writing unit, the reset signal includes the reset signal provided by the power signal terminal and / or the reset signal provided by the data writing signal terminal; and, under the control of the fourth control signal terminal, the amount of electricity stored in the second storage unit is discharged through the charge and discharge control unit and the display light-emitting unit in the pixel circuit;

[0022] In a detection phase, the data writing unit is turned off, and under the control of the first control signal terminal, the third control signal terminal, and the fourth control signal terminal, a power reference signal provided by the power signal terminal is provided to the first node, and a reference voltage signal provided by the reference voltage terminal is provided to the second node, so as to charge the first storage unit and the second storage unit based on the voltage of the first node;

[0023] In the data input phase, the charge and discharge control unit and the drive control unit are turned off, and under the control of the second control signal terminal, the data input signal of the data signal terminal is provided to the first node;

[0024] In the light-emitting stage, the data writing unit and the reset unit are turned off, and under the control of the fourth control signal terminal, a discharge compensation signal is output to the third node based on the amount of electricity stored in the second storage unit, and, under the control of the potential of the first node, a driving signal is output to the third node through the driving unit, and the driving signal is used to drive the display light-emitting unit to emit light.

[0025] In a third aspect, an embodiment of the present application provides a display panel, comprising a pixel circuit as described in any one of the first aspects.

[0026] In a fourth aspect, an embodiment of the present application provides a display device, comprising: a display panel as described in the third aspect and a power supply module, wherein the power supply module is used to control power supply to the display panel.

[0027] In summary, the pixel circuit and its driving method, display device, and equipment provided in the embodiments of the present application provide, through the driving control unit, the power signal provided by the power signal end to the first node under the control of the first control signal end, and the data input signal of the data signal end to the first node under the control of the second control signal end through the data writing unit, so that the driving unit outputs a driving signal to the third node under the control of the potential of the first node to drive the display light-emitting unit to emit light, and under the control of the third control signal end, the reference voltage signal of the reference voltage end is provided to the second node through the reset unit, so that the charge and discharge control unit outputs a discharge compensation signal to the third node based on the amount of electricity stored in the second storage unit under the control of the fourth control signal end, thereby realizing threshold voltage compensation, so that the current passing through the display light-emitting unit is independent of the threshold voltage of the driving unit, and can provide a stable current for the display light-emitting unit, thereby solving the pixel circuit problem caused by threshold voltage changes in the existing related technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0031] Figure 1 A schematic structural diagram of a pixel circuit provided in an embodiment of the present application;

[0032] Figure 2 A schematic structural diagram of a pixel circuit provided in an optional embodiment of the present application;

[0033] Figure 3 A driving timing diagram of a pixel circuit provided as an example of the present application;

[0034] Figure 4 A schematic diagram of the circuit principle of a pixel circuit in the reset phase provided as an example of this application;

[0035] Figure 5 A schematic diagram of the circuit principle of a pixel circuit in the detection stage provided as an example of this application;

[0036] Figure 6 A schematic diagram of the circuit principle of a pixel circuit in the data input stage provided as an example of this application;

[0037] Figure 7 A schematic diagram of the circuit principle of a pixel circuit in the light-emitting stage provided as an example of this application;

[0038] Figure 8 A schematic flow chart of the steps of a driving method for a pixel circuit provided in an embodiment of the present application;

[0039] Figure 9 A structural block diagram of a display panel provided in an embodiment of the present application;

[0040] Figure 10 This is a structural block diagram of a display device provided in an embodiment of the present application.

[0041] Among them, VDD is the power signal terminal, VS is the reference voltage terminal, Vdate is the data signal terminal, 110 is the driving control unit, 120 is the data writing unit, 130 is the reset unit, 140 is the charge and discharge control unit, 150 is the driving unit, 160 is the first storage unit, 170 is the second storage unit, 180 is the display light-emitting unit, V1 is the first control signal terminal, V2 is the second control signal terminal, V3 is the third control signal terminal, V4 is the fourth control signal terminal, T1 is the driving control transistor, T2 is the data writing transistor, T3 is the reset transistor, T4 is the first charge and discharge control transistor, T5 is the driving transistor, N1 is the first node, N2 is the second node, N3 is the third node, C1 is the first capacitor, C2 is the second capacitor, C3 is the third capacitor, D1 is the light-emitting device, 900 is the display panel, 910 is the pixel circuit, 1000 is the display device, and 1011 is the power supply module. DETAILED DESCRIPTION

[0042] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] The disclosure below provides many different embodiments or examples for implementing different configurations of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0044] It should be noted that the shift in threshold voltage can be attributed to charge trapping in the gate dielectric and the interface state of the semiconductor material. Addressing the threshold voltage shift issue at the base level requires device-level solutions, including optimizing the ZnO-dielectric interface through careful selection of dielectric materials, exploiting the secondary gate effect through the design of dual-gate thin-film field-effect transistors (TFTs), process optimization, and the asymmetric structure of TFTs. Furthermore, this threshold voltage shift issue can also be addressed at the circuit level, specifically by designing pixel circuits to compensate for changes in threshold voltage through the design of compensation pixel circuits. These compensation pixel circuits can be broadly categorized as current-programmed pixel circuits and voltage-programmed pixel circuits. While current-programmed pixel circuits provide precise compensation, they come at the expense of longer stabilization times due to the presence of parasitic capacitance. Given the fast programming time offered by voltage programming, current related technologies primarily utilize voltage programming to achieve threshold voltage compensation, but this requires more complex pixel circuits and presents the problem of the complexity of voltage-programmed pixel circuits.

[0045] In order to solve the above technical problems, the embodiments of the present application provide a pixel circuit and its driving method, display device, and equipment, wherein a driving control unit provides a power signal provided by a power signal end to a first node under the control of a first control signal end, and provides a data input signal of a data signal end to the first node under the control of a second control signal end through a data writing unit, and provides a reference voltage signal of a reference voltage end to a second node through a reset unit under the control of a third control signal end, wherein the second node is a node connected to the reset unit, the second end of the first storage unit, and the first end of the second storage unit, the first end of the first storage unit is electrically connected to the first node, and the second end of the second storage unit is electrically connected to the charge and discharge control unit, so that the charge and discharge control unit Under the control of the fourth control signal terminal, a discharge compensation signal can be output to the third node based on the amount of electricity stored in the second storage unit, so that threshold voltage compensation can be achieved through the discharge compensation signal, and the third node is a node where the charge and discharge control unit is connected to the driving unit and the display light-emitting unit. The driving unit outputs a driving signal to the third node under the potential control of the first node, so as to drive the display light-emitting unit to emit light through the driving signal, and then the input voltages of the first control signal terminal, the second control signal terminal, the third control signal terminal, the fourth control signal terminal, the power signal terminal and the data input signal terminal can be controlled by voltage programming to achieve threshold voltage compensation, so that the current passing through the display light-emitting unit is independent of the threshold voltage of the driving unit, and a stable current can be provided for the display light-emitting unit.

[0046] Figure 1A schematic diagram of the structure of a pixel circuit provided in an embodiment of the present application. This embodiment may specifically include: a driving control unit 110, a data writing unit 120, a reset unit 130, a charge and discharge control unit 140, a driving unit 150, a first storage unit 160, a second storage unit 170 and a display light-emitting unit 180. The driving control unit 110 is used to provide the power signal provided by the power signal terminal VDD to the first node N1 under the control of the first control signal terminal V1; the data writing unit 120 is used to provide the data input signal of the data signal terminal Vdate to the first node N1 under the control of the second control signal terminal V2; the reset unit 130 is used to provide the reference voltage signal of the reference voltage terminal VS to the second node N2 under the control of the third control signal terminal V3. The second node N2 is a node connecting the reset unit 130 with the second end of the first storage unit 160 and the first end of the second storage unit 170. The first storage unit 160 and the second end of the second storage unit 170 are connected. One end is electrically connected to the first node N1, and the second end of the second storage unit 170 is electrically connected to the charge and discharge control unit 140; the charge and discharge control unit 140 is used to output a discharge compensation signal to the third node N3 based on the amount of electricity stored in the second storage unit 170 under the control of the fourth control signal terminal V4, and the third node N3 is a node connecting the charge and discharge control unit 140, the drive control unit 150 and the display light-emitting unit 180; the drive control unit 150 is used to output a drive signal to the third node N3 under the control of the potential of the first node N1, and the drive signal is used to drive the display light-emitting unit 180 to emit light.

[0047] Specifically, in the case where the first control signal terminal V1 outputs a valid first control signal, the driving control unit 110 can provide the power signal provided by the power signal terminal VDD to the first node N1 according to the first control signal, and the power signal provided by the power signal terminal VDD is transmitted to the first node N1 through the driving control unit, and the first node N1 is a node where the control terminal of the driving control unit 150 is connected to the driving control unit 110, the first storage unit 160 and the data writing unit 120, so that the driving control unit 150 can output a driving signal to the third node N3 under the potential control of the first node N1, so as to drive the display light-emitting unit 180 to emit light through the driving signal; and, in the case where the third control signal terminal V3 outputs a valid third control signal, the reset unit 130 is used to reset the display light-emitting unit 180 according to the third control signal. The reference voltage signal of the reference voltage terminal VS is provided to the second node N2 to write the voltage of the reference voltage signal into the second node N2, thereby resetting the second node N2; and when the fourth control signal terminal V4 outputs a valid fourth control signal, the charge and discharge control unit 140 is turned on to control the charging and discharging of the second storage unit 170 through the charge and discharge control unit 140, so that the charge and discharge control unit 140 can output a discharge compensation signal to the third node N3 based on the amount of electricity stored in the second storage unit 170 under the control of the fourth control signal terminal V4, so as to achieve threshold voltage compensation through the discharge compensation signal, so that the current passing through the display light-emitting unit 180 is independent of the threshold voltage of the driving control unit 150, thereby being able to provide a stable current for the display light-emitting unit 180, thereby solving the pixel circuit problem caused by the threshold voltage change in the existing related technology.

[0048] It can be seen that in the embodiment of the present application, the driving control unit 110 provides the power signal provided by the power signal terminal VDD to the first node N1 under the control of the first control signal terminal V1, and provides the data input signal of the data signal terminal Vdate to the first node N1 through the data writing unit 120 under the control of the second control signal terminal V2, so that the driving control unit 150 outputs a driving signal to the third node N3 under the control of the potential of the first node N1 to drive the display light-emitting unit 180 to emit light, and under the control of the third control signal terminal V3, the reference voltage signal of the reference voltage terminal VS is provided to the second node N2 through the reset unit 130, so that the charge and discharge control unit 140 outputs a discharge compensation signal to the third node N3 based on the amount of electricity stored in the second storage unit 170 under the control of the fourth control signal terminal V4 to achieve threshold voltage compensation, so that the current passing through the display light-emitting unit 180 is independent of the threshold voltage of the driving control unit 150, and can provide a stable current for the display light-emitting unit 180, thereby solving the pixel circuit problem caused by threshold voltage variation in the existing related art.

[0049] In addition, when the second control signal terminal V2 outputs a valid second control signal, the data write unit 120 provides the data input signal of the data signal terminal Vdate to the first node N1 according to the second control signal, so as to write the data voltage VData of the data input signal into the first node N1, thereby realizing data voltage writing.

[0050] In some optional embodiments of the present application, the data writing unit 120 includes a data writing transistor T2, such as Figure 2 As shown, the control end of the data write transistor T2 is electrically connected to the second control signal end V2, the first end of the data write transistor T2 is electrically connected to the data signal end Vdate, and the second end of the data write transistor T2 is electrically connected to the first node N1, so that the data write transistor T2 can provide the data input signal of the data signal end Vdate to the first node N1 under the control of the second control signal end V2, so as to write the data voltage VData of the data input signal into the first node N1, thereby realizing data voltage writing.

[0051] In an optional embodiment of the present application, a thin film transistor can be used as the driving control transistor T1 to implement the driving control unit 110, so that the power signal provided by the power signal terminal VDD is provided to the first node N1 under the control of the first control signal terminal V1 through the driving control transistor T1. Figure 2 As shown, the driving control unit 110 includes: a driving control transistor T1; a first end of the driving control transistor T1 is electrically connected to the first end of the driving control unit 150 and the power signal end VDD, the control end of the driving control transistor T1 is electrically connected to the first control signal end V1, and the second end of the driving control transistor T1 is electrically connected to the first node N1, so that the driving control transistor T1 can provide the power signal provided by the power signal end VDD to the first node N1 under the control of the first control signal end V1, thereby enabling the driving control unit 150 to output a driving signal related to the data input signal at the potential control of the first node N1, so as to drive the display light-emitting unit 180 to emit display according to the driving current corresponding to the driving signal, thereby realizing the display function of the pixel circuit.

[0052] Optionally, in the embodiment of the present application, the driving control unit 150 may be implemented using a driving transistor T5. The driving transistor T5 may output a driving signal to the third node N3 based on a power signal provided by the power signal terminal VDD under the potential control of the first node N1, thereby driving the display light-emitting unit 180 to emit light through the driving signal. The first node N1 is a node where the control terminal of the driving control transistor T1 is connected to the second terminal of the driving control unit 110, the first storage unit 160, and the data writing unit 120.

[0053] For example, Figure 3 As shown, the driving control unit 150 includes a driving transistor T5; the first end of the driving transistor is electrically connected to the power signal end VDD, the control end of the driving transistor T5 is electrically connected to the first node N1, and the second end of the driving transistor T5 is electrically connected to the third node N3, so that the driving transistor T5 can output a driving signal to the third node N3 under the control of the potential of the first node N1, so as to drive the display light-emitting unit 180 to emit light through the driving signal.

[0054] In one embodiment of the present application, in order to simplify the circuit structure, the reset unit 130 can be implemented using a reset transistor T3, so that the reference voltage signal of the reference voltage terminal VS is provided to the second node N2 through the reset transistor T3 under the control of the third control signal terminal V3, so that the second node N2 can be reset by the reference voltage signal provided by the reference voltage terminal VS. Figure 2 As shown, the reset unit 130 includes: a reset transistor T3; a first end of the reset transistor T3 is electrically connected to the reference voltage terminal VS, a second end of the reset transistor T3 is electrically connected to the second node N2, and a control end of the reset transistor T3 is electrically connected to the third control signal terminal V3, so that the reset transistor T3 provides the reference voltage signal of the reference voltage terminal VS to the second node N2 under the control of the third control signal terminal V3, so that the second node N2 can be reset by the reference voltage signal provided by the reference voltage terminal VS. For example, in the case where the ground terminal of the pixel circuit is used as the reference voltage terminal VS, the reference ground signal of the ground terminal can be used as the reference voltage signal provided by the reference voltage terminal VS and transmitted to the second node N2 to reset the second node N2 by the reference ground signal.

[0055] In some optional embodiments of the present application, the charge and discharge control unit 140 includes a charge and discharge control transistor T4, the control end of the charge and discharge control transistor T4 is electrically connected to the fourth control signal end V4, the first end of the charge and discharge control transistor T4 is electrically connected to the second end of the second storage unit 170, and the second end of the charge and discharge control transistor T4 is electrically connected to the third node N3, so that the charge and discharge control transistor T4 can be turned on under the control of the fourth control signal end V4, and then generate a discharge compensation signal based on the amount of electricity stored in the second storage unit 170, so as to transmit the discharge compensation signal to the third node N3 through the turned-on charge and discharge control transistor T4, so that the display light-emitting unit 180 emits light based on the potential of the third node N3.

[0056] In some optional embodiments of the present application, the first storage unit 160 in the pixel circuit can be implemented by a capacitor. Figure 2 As shown, the first storage unit 160 includes a first capacitor C1, the first end of the first capacitor C1 is electrically connected to the first node N1, the second end of the first capacitor C1 and the first end of the second storage unit 170 are both electrically connected to the second node N2, and the second end of the second storage unit 170 is electrically connected to the first end of the charge and discharge control unit 140, so that the potential of the first node N1 can be stored through the first capacitor C1.

[0057] Of course, in addition to using a capacitor to implement the first storage unit 160 in the pixel circuit, the embodiment of the present application can also use a capacitor to implement the second storage unit 170, so as to achieve threshold voltage compensation by controlling the charging and discharging of the second storage unit 170. Figure 2 As shown, the second storage unit 170 includes a second capacitor C2. The first end of the first capacitor C1 is electrically connected to the first node N1. The second end of the first capacitor C1 and the first end of the second capacitor C2 are both electrically connected to the second node N2. The second end of the second capacitor C2 is electrically connected to the first end of the charge-discharge control unit 140. Therefore, the charge-discharge control unit 140 can control the charge and discharge of the second capacitor C2 to achieve threshold voltage compensation and provide a stable OLED current. The OLED current refers to the current passing through the light-emitting device in the display light-emitting unit 180.

[0058] In an optional embodiment of the present application, a single TFT can be used as the driving transistor T5 in the driving control unit 150, and four switching TFTs can be used as the driving control transistor, data writing transistor T2, reset transistor T3, and charge-discharge control unit 140, respectively. Two storage capacitors can be used as the first storage unit 160 and the second storage unit 170, respectively, to achieve drive control of the display light-emitting unit 180 through five TFTs and two storage capacitors. The display light-emitting unit 180 can include a third capacitor C3 and a light-emitting device D1, wherein the anode of the light-emitting device D1 is electrically connected to one end of the third capacitor C3 and the third node N3, and the other end of the third capacitor C3 is electrically connected to the cathode of the light-emitting device D1 and the reference voltage terminal VS, so that the light-emitting device D1 can emit light based on the driving signal output by the driving transistor T5 and the discharge compensation signal output by the charge-discharge control transistor T4. Optionally, the light-emitting device D1 can be an OLED, which is not limited in this embodiment of the present application.

[0059] Indium Gallium Zinc Oxide (IGZO) itself has low leakage. For example, a-IGZO thin-film transistors have advantages such as transparency, high electron mobility, good uniformity, and a high on-off current ratio. Therefore, in an optional embodiment of the present application, a-IGZO thin-film transistors can be used for the driving transistor T5, the driving control transistor, the reset transistor T3, the data writing transistor T2, and the charge and discharge control transistor to improve the leakage and enable the pixel circuit to achieve low-frequency operation.

[0060] In a specific implementation, the first control signal, the second control signal, the third control signal and the fourth control signal output by the first control signal terminal V1, the second control signal terminal V2, the third control signal terminal V3 and the fourth control signal terminal V4 can be controlled by voltage programming, so that the driving control transistor T1 can turn on the driving transistor T5 in the detection phase, and the data voltage VData can be written in the data writing transistor T2, and the charging and discharging of the second capacitor C2 can be controlled by the charge and discharge control transistor T4, and the first capacitor C1 and the second capacitor C2 can be reset by the reset transistor T3 in the reset phase.

[0061] Specifically, the driving process of the pixel circuit provided in the embodiment of the present application can be divided into four working stages: the first stage can be the reset stage, the second stage can be the detection stage, the third stage can be the data input stage, and the fourth stage is the light-emitting stage.

[0062] The following takes the case where all transistors in the pixel circuit are N-type TFTs as an example, that is, when the drive control transistor T1, the data writing transistor T2, the reset transistor T3, the charge and discharge control transistor T4, and the drive transistor T5 are all N-type TFTs, a high-level signal can be output as a valid switch control signal to control the conduction of each transistor in the pixel circuit; and a low-level signal can be output as an invalid switch control signal to control the turn-off of each transistor in the pixel circuit, thereby realizing the driving of the pixel circuit.

[0063] Specifically, in the reset phase, the first control signal terminal V1, the second control signal terminal V2, the third control signal terminal V3 and the fourth control signal terminal V4 can be controlled by voltage programming to output high-level signals as the effective first control signal, the second control signal, the third control signal and the fourth control signal, such as Figure 3 As shown, the drive control transistor T1, the data writing transistor T2, the reset transistor T3 and the charge and discharge control transistor T4 are turned on. Figure 4 As shown, the reference voltage signal provided by the reference voltage terminal VS can be used as a reset signal and transmitted to the first node N1 through the driving control transistor T1 to achieve the reset of the first node N1, and the data input signal provided by the data write signal terminal can also be used as a reset signal and transmitted to the first node N1 through the data write transistor T2. In addition, the reset transistor T3 and the charge and discharge control transistor T4 are turned on, so that the first capacitor C1 and the second capacitor C2 can be discharged through the reset transistor T3, the charge and discharge control transistor T4 and the OLED to discharge to a default reset voltage that is independent of the voltage distribution of the previous cycle, thereby resetting the second node N2. Among them, the reference voltage signal provided by the reference voltage terminal VS can be a low-level signal of 0V, which serves as a reset signal to achieve the reset of the first node N1; the reference voltage signal provided by the reference voltage terminal VS can be a reference ground signal provided by the circuit reference ground, and the embodiments of the present application are not limited to this.

[0064] In the detection phase, the second control signal terminal V2 can be controlled to output a low-level signal as an invalid second control signal through voltage programming to turn off the data writing transistor T2. Figure 5As shown, the driving control transistor T1, the reset transistor T3, and the charge-discharge control transistor T4 remain in the on state, and a power reference signal equal to 5.1V can be applied to the power signal terminal VDD to be transmitted to the first node N1 through the turned-on driving control transistor T1, so as to charge the first capacitor C1 in the first storage unit based on the voltage of the first node N1. The driving transistor T5 is turned on under the potential control of the first node N1, and the driving transistor T5 in the turned-on state is equivalent to a diode, so that the voltage of the power reference signal is applied to the gate and drain of the driving transistor T5, and then the second capacitor C2 can be charged through the driving transistor T5 and the charge-discharge control transistor T4, so that the voltage of the second capacitor C2 is charged to the voltage difference between the voltage Vref of the power reference signal and the threshold voltage VTH, that is, charged to the Vref-VTH level.

[0065] In the data input stage, the first control signal terminal V1 and the fourth control signal terminal V4 are controlled to output low-level signals as invalid first control signals and invalid fourth control signals through voltage programming to turn off the driving control transistor T1 and the charge and discharge control transistor T4. Figure 6 As shown, it is possible to ensure that the second capacitor C2 does not discharge and remains in a charged state under the Vref-VTH voltage, and during the data input process, the second control signal terminal V2 is controlled to output a high-level signal as a valid second control signal, so that the data write transistor T2 is turned on, so that under the control of the second control signal terminal V2, the data input signal of the data signal terminal Vdate is provided to the first node N1 through the data write transistor T2, so that the first capacitor C1 can be charged based on the data voltage VData corresponding to the data input signal, so as to charge the voltage of the first capacitor C1 to the data voltage VData corresponding to the data input signal, thereby realizing the writing of the data voltage VData.

[0066] In the light-emitting stage, the second control signal terminal V2 and the third control terminal can be controlled by voltage programming to output a low-level signal as an invalid second control signal and an invalid third control signal, turning off the data writing transistor T2 and the reset transistor T3, and the fourth control signal terminal V4 can be controlled to output a high-level signal as a valid fourth control signal, turning on the charge and discharge control transistor T4. Figure 7 As shown, the source-drain voltage VGS of the driving transistor T5 from the gate to the source terminal becomes the voltage difference between the voltage VC1 of the first capacitor C1 and the voltage VC2 of the second capacitor C2, that is, VGS=VC1-VC2.

[0067] According to the calculation formula of the current passing through OLED By calculation, the OLED current I during the light-emitting phase can be determined. OLED for That is, the OLED current in the light-emitting phase is independent of the threshold voltage of the driving transistor T5, and the proposed pixel circuit can compensate for the change of the threshold voltage VTH and provide a stable OLED current. The specific calculation process is as follows:

[0068]

[0069]

[0070] Where K is the calculation coefficient related to the mobility μn and intrinsic capacitance Cox of the TFT tube; V GS is the voltage difference between the source and the drain of the driving transistor T5, and VTH is the threshold voltage of the driving transistor T5.

[0071] It can be seen that in the pixel circuit provided in the embodiment of the present application, the OLED current in the light-emitting stage is independent of the threshold voltage of the driving transistor T5, that is, it can compensate for the change of the threshold voltage VTH and provide a stable OLED current, thereby solving the problem of threshold voltage movement at the circuit level. For example, the pixel circuit provided in the embodiment of the present application can be used as a novel AMOLED pixel circuit for use in an AMOLED display, so that the AMOLED display can control the voltages of the first control signal terminal V1, the second control signal terminal V2, the third control signal terminal V3, and the fourth control signal terminal V4 through voltage programming, and control the voltage applied to the power signal terminal VDD and the data signal terminal Vdate, so as to utilize the charging rate of the diode-connected TFT source node to reduce to more than VDD-VTH to compensate for the threshold voltage change, thereby providing a stable OLED current to extend the service life of the AMOLED display.

[0072] Furthermore, an embodiment of the present application also provides a display driving method for driving a pixel circuit as described in any one of the above embodiments. Figure 8 As shown, a display driving method provided in an embodiment of the present application may specifically include:

[0073] S101, a reset stage, under the control of a third control signal terminal and a fourth control terminal, providing a reference voltage signal of a reference voltage terminal to a second node, the second node being a node where a reset unit in the pixel circuit is connected to the second terminal of the first storage unit and the first terminal of the second storage unit; and under the control of a target control signal terminal, resetting the first node of the pixel circuit by a reset signal, the target control signal terminal including a first control signal terminal and / or a second control signal terminal, the first node being a node where a driving unit in the pixel circuit is connected to a driving control unit, the first storage unit and a data writing unit, the reset signal including a reset signal provided by the power signal terminal and / or a reset signal provided by the data writing signal terminal; and, under the control of a fourth control signal terminal, discharging the electricity stored in the second storage unit through a charge and discharge control unit and a display light-emitting unit in the pixel circuit;

[0074] S102, a detection phase, turning off the data writing unit, and under the control of the first control signal terminal, the third control signal terminal, and the fourth control signal terminal, providing a power reference signal provided by the power signal terminal to the first node, and providing a reference voltage signal provided by the reference voltage terminal to the second node, so as to charge the first storage unit and the second storage unit based on the voltage of the first node;

[0075] S103, data input stage, turning off the charge and discharge control unit and the drive control unit, and providing the data input signal of the data signal terminal to the first node under the control of the second control signal terminal.

[0076] S104, light-emitting stage, turns off the data writing unit and the reset unit, and under the control of the fourth control signal terminal, outputs a discharge compensation signal to the third node based on the amount of electricity stored in the second storage unit, and, under the control of the potential of the first node, outputs a driving signal to the third node through the driving unit, and the driving signal is used to drive the display light-emitting unit to emit light.

[0077] It can be seen that in the embodiment of the present application, the driving control unit provides the power signal provided by the power signal end to the first node under the control of the first control signal end, and provides the data input signal of the data signal end to the first node under the control of the second control signal end through the data writing unit, so that the driving unit outputs the driving signal to the third node under the control of the potential of the first node to drive the display light-emitting unit to emit light, and under the control of the third control signal end, the reference voltage signal of the reference voltage end is provided to the second node through the reset unit, so that the charge and discharge control unit outputs the discharge compensation signal to the third node based on the amount of electricity stored in the second storage unit under the control of the fourth control signal end, thereby realizing threshold voltage compensation, so that the current passing through the display light-emitting unit is independent of the threshold voltage of the driving unit, and can provide a stable current for the display light-emitting unit, thereby solving the pixel circuit problem caused by the threshold voltage change in the existing related technology.

[0078] Optionally, the target signal terminal in the embodiment of the present application may include a first control terminal and / or a second control signal terminal, and the reset signal includes a first data signal provided by the data write terminal and / or a first power signal provided by the power signal terminal. For example, when the drive control transistor, the data write transistor, the reset transistor, the charge and discharge control transistor, and the drive transistor are all N-type TFTs, a low-level signal can be used as the first data signal provided by the data write terminal, so that the low-level signal is used as the reset signal in the reset stage, and is transmitted to the first node through the turned-on data write transistor to achieve the reset of the first node; in addition, a low-level signal can be used as the first power signal provided by the power signal terminal, so that the low-level signal is used as the reset signal in the reset stage, and is transmitted to the first node through the turned-on drive control transistor to achieve the reset of the first node.

[0079] Furthermore, an embodiment of the present application provides a display panel. Figure 9 As shown, the display panel 900 in the embodiment of the present application includes a pixel circuit 910, which can be any of the pixel circuits provided in the above-mentioned embodiments of the present invention. Since the principle of solving the problem of this display panel is similar to that of the above-mentioned pixel circuit, the implementation of the pixel circuit in this display panel can refer to the implementation of the pixel circuit in the above-mentioned example, and the repeated parts are not repeated here.

[0080] The embodiment of the present invention further provides a display device, comprising the display panel provided by the embodiment of the present invention and a power supply module, wherein the power supply module is used to control the power supply to the display panel. Figure 10As shown, the display device 1000 includes a display panel 900 and a power supply module 1011. The power supply module 1011 is used to control the power supply to the display panel 900. The display panel 900 can be the display panel described in the above embodiment. In a specific implementation, the display device can be a monitor, a mobile phone, a television, a laptop computer, an electronic paper, a digital photo frame, a navigation system, etc., which is not specifically limited in this application.

[0081] According to the display device of the embodiment of the present application, the display panel in the above embodiment is adopted. The display device provides the power signal provided by the power signal end to the first node under the control of the first control signal end through the driving control unit, and provides the data input signal of the data signal end to the first node under the control of the second control signal end through the data writing unit, so that the driving unit outputs the driving signal to the third node under the control of the potential of the first node to drive the display light-emitting unit to emit light, and under the control of the third control signal end, the reference voltage signal of the reference voltage end is provided to the second node through the reset unit, so that the charge and discharge control unit outputs the discharge compensation signal to the third node based on the amount of electricity stored in the second storage unit under the control of the fourth control signal end, thereby realizing threshold voltage compensation, so that the current passing through the display light-emitting unit is independent of the threshold voltage of the driving unit, and can provide a stable current for the display light-emitting unit, thereby solving the pixel circuit problem caused by the threshold voltage change in the existing related technology.

[0082] The panel and device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of these modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0083] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, or of course, by hardware. Based on this understanding, the above technical solution, in essence, or the part that contributes to the relevant technology, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiment.

[0084] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0085] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A pixel circuit, characterized in that: include: A driving control unit, a data writing unit, a reset unit, a charge and discharge control unit, a driving unit, a first storage unit, a second storage unit and a display light-emitting unit; The driving control unit is configured to provide the power signal provided by the power signal terminal to the first node under the control of the first control signal terminal; The data writing unit is configured to provide a data input signal from a data signal terminal to the first node under the control of a second control signal terminal; The reset unit is configured to provide a reference voltage signal from the reference voltage terminal to a second node under the control of the third control signal terminal, wherein the second node is a node where the reset unit is connected to the second terminal of the first storage unit and the first terminal of the second storage unit, the first terminal of the first storage unit is electrically connected to the first node, and the second terminal of the second storage unit is electrically connected to the charge and discharge control unit; The charge and discharge control unit is configured to output a discharge compensation signal to a third node based on the amount of electricity stored in the second storage unit under the control of a fourth control signal terminal, wherein the third node is a node connecting the charge and discharge control unit, the driving unit, and the display light-emitting unit; The driving unit is configured to output a driving signal to the third node under the control of the potential of the first node, wherein the driving signal is configured to drive the display light-emitting unit to emit light.

2. The pixel circuit according to claim 1, wherein: The driving control unit includes: a driving control transistor; The first end of the drive control transistor is electrically connected to the first end of the drive unit and the power signal end, the control end of the drive control transistor is electrically connected to the first control signal end, and the second end of the drive control transistor is electrically connected to the first node, which is a node connecting the control end of the drive unit, the first end of the first storage unit, and the data writing unit.

3. The pixel circuit according to claim 1, wherein: The driving unit includes a driving transistor; The first terminal of the driving crystal is electrically connected to the power signal terminal, the control terminal of the driving transistor is electrically connected to the first node, and the second terminal of the driving transistor is electrically connected to the third node.

4. The pixel circuit according to claim 1, wherein: The reset unit includes: a reset transistor; The first terminal of the reset transistor is electrically connected to the reference voltage terminal, the second terminal of the reset transistor is electrically connected to the second node, and the control terminal of the reset transistor is electrically connected to the third control signal terminal.

5. The pixel circuit according to claim 1, wherein: The data writing unit includes a data writing transistor, a control terminal of the data writing transistor is electrically connected to the second control signal terminal, a first terminal of the data writing transistor is electrically connected to the data signal terminal, and a second terminal of the data writing transistor is electrically connected to the first node.

6. The pixel circuit according to claim 1, wherein: The charge and discharge control unit includes a charge and discharge control transistor, a control end of the charge and discharge control transistor is electrically connected to the fourth control signal end, a first end of the charge and discharge control transistor is electrically connected to the second end of the second storage unit, and a second end of the charge and discharge control transistor is electrically connected to the third node.

7. The pixel circuit according to any one of claims 1 to 6, characterized in that: The first storage unit includes a first capacitor, and the second storage unit includes a second capacitor, wherein a first end of the first capacitor is electrically connected to the first node, a second end of the first capacitor and a first end of the second capacitor are both electrically connected to the second node, and a second end of the second capacitor is electrically connected to the first end of the charge and discharge control unit; The display light-emitting unit includes a third capacitor and a light-emitting device, the anode of the light-emitting device is electrically connected to one end of the third capacitor and the third node, and the other end of the third capacitor is electrically connected to the cathode of the light-emitting device and the reference voltage end.

8. A method for driving a pixel circuit, characterized in that: A method for driving a pixel circuit according to any one of claims 1 to 7, comprising: In the reset stage, under the control of the third control signal terminal and the fourth control terminal, the reference voltage signal of the reference voltage terminal is provided to the second node, the second node being a node where the reset unit in the pixel circuit is connected to the second terminal of the first storage unit and the first terminal of the second storage unit; and under the control of the target control signal terminal, the first node of the pixel circuit is reset by a reset signal, the target control signal terminal includes the first control signal terminal and / or the second control signal terminal, the first node is a node where the driving unit in the pixel circuit is connected to the driving control unit, the first storage unit and the data writing unit, the reset signal includes the reset signal provided by the power signal terminal and / or the reset signal provided by the data writing signal terminal; and, under the control of the fourth control signal terminal, the amount of electricity stored in the second storage unit is discharged through the charge and discharge control unit and the display light-emitting unit in the pixel circuit; In a detection phase, the data writing unit is turned off, and under the control of the first control signal terminal, the third control signal terminal, and the fourth control signal terminal, a power reference signal provided by the power signal terminal is provided to the first node, and a reference voltage signal provided by the reference voltage terminal is provided to the second node, so as to charge the first storage unit and the second storage unit based on the voltage of the first node; In the data input phase, the charge and discharge control unit and the drive control unit are turned off, and under the control of the second control signal terminal, the data input signal of the data signal terminal is provided to the first node; In the light-emitting stage, the data writing unit and the reset unit are turned off, and under the control of the fourth control signal terminal, a discharge compensation signal is output to the third node based on the amount of electricity stored in the second storage unit, and, under the control of the potential of the first node, a driving signal is output to the third node through the driving unit, and the driving signal is used to drive the display light-emitting unit to emit light.

9. A display panel, characterized in that: The display panel comprises the pixel circuit according to any one of claims 1 to 7.

10. A display device, characterized in that: include: The display panel and power supply module according to claim 9, wherein the power supply module is used to control the power supply to the display panel.

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