Pixel circuit, driving method thereof and display panel

Abstract

The application discloses a pixel circuit, a driving method thereof and a display panel. The pixel circuit comprises a driving module, a first end of the driving module being connected with a first voltage source; an adjustable capacitance module, a second end of the adjustable capacitance module being connected with a control end of the driving module, a first end of the adjustable capacitance module being connected with a second voltage source, so as to adjust a capacitance value of the adjustable capacitance module according to an output voltage of the second voltage source; and a light-emitting module, a first end of the light-emitting module being connected with a second end of the driving module, and a second end of the light-emitting module being connected with a third voltage source. In this way, the pixel circuit can adjust the capacitance value of the adjustable capacitance module according to the output voltage of the second voltage source, so as to use the output voltage of the second voltage source required by a low capacitance value when high-frequency display is performed, thereby shortening the charging time of the adjustable capacitance module and ensuring compensation effect; and the output voltage of the second voltage source required by a high capacitance value is used when low-frequency display is performed, thereby ensuring that the light-emitting module is stable and does not flicker.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display panels, in particular to a pixel circuit, a driving method thereof and a display panel. BACKGROUND

[0002] Nowadays, with the continuous development of display technology, people's demand for improving the refresh rate of the screen is also increasing. However, the pixel circuit in the traditional display panel usually adopts a 7T1C (7 transistors 1 capacitor) circuit. Since the charging capacitor Cst in the 7T1C circuit usually has a fixed capacitance value, the charging time is limited. Therefore, when the 7T1C circuit performs Vdata (data voltage signal) write compensation, there is a problem of insufficient compensation in high-frequency display, and there is a problem of unstable voltage leading to flickering of the light-emitting device in low-frequency display. SUMMARY

[0003] The technical problem solved by the present application is to provide a pixel circuit, a driving method thereof and a display panel, which can solve the problem of insufficient compensation in high-frequency display and the problem of unstable voltage leading to flickering of the light-emitting device in low-frequency display in the pixel circuit of the prior art.

[0004] To solve the above technical problems, one technical solution adopted by the present application is to provide a pixel circuit, wherein the pixel circuit comprises: a driving module, a first end of the driving module being connected to a first voltage source; an adjustable capacitor module, a second end of the adjustable capacitor module being connected to a control end of the driving module, a first end of the adjustable capacitor module being connected to a second voltage source, so as to adjust the capacitance value of the adjustable capacitor module according to the output voltage of the second voltage source; and a light-emitting module, a first end of the light-emitting module being connected to a second end of the driving module, a second end of the light-emitting module being connected to a third voltage source.

[0005] Among them, the second voltage source has at least two output voltages when the pixel circuit corresponds to at least two refresh frequencies, and the adjustable capacitor module has at least two capacitance values corresponding to the at least two output voltages; wherein the output voltage is positively correlated with the refresh frequency and negatively correlated with the capacitance value.

[0006] Among them, the second voltage source has a first output voltage when the pixel circuit corresponds to a first refresh frequency, and the adjustable capacitor module has a first capacitance value corresponding to the first output voltage; the second voltage source has a second output voltage when the pixel circuit corresponds to a second refresh frequency, and the adjustable capacitor module has a second capacitance value corresponding to the second output voltage; wherein the first refresh frequency is greater than the second refresh frequency, the first output voltage is greater than the second output voltage, and the first capacitance value is less than the second capacitance value.

[0007] The pixel circuit further comprises a compensation module, a first end of the compensation module is connected to the control end of the driving module, a second end of the compensation module is connected to the second end of the driving module, and a third end of the compensation module is connected to the second scan line, for controlling the communication between the control end of the driving module and the second end of the driving module.

[0008] The pixel circuit further comprises a first initialization module and a second initialization module, a first end of the first initialization module is connected to the control end of the driving module, a second end of the first initialization module is connected to a first end of the second initialization module and the reference voltage line, and a third end of the first initialization module is connected to the first scan line, and a second end of the second initialization module is connected to the first end of the light-emitting module, and a third end of the second initialization module is connected to the first scan line, for controlling the initial voltage to be written into the second end of the adjustable capacitor module and the first end of the light-emitting module.

[0009] The pixel circuit further comprises a data writing module, a first end of the data writing module is connected to the data line, a second end of the data writing module is connected to the first end of the driving module, and a third end of the data writing module is connected to the second scan line, for providing the data voltage on the data line to the first end of the driving module.

[0010] The pixel circuit further comprises a first light-emitting control module and a second light-emitting control module, a first end of the first light-emitting control module is connected to the first voltage source, a second end of the first light-emitting control module is connected to the first end of the driving module, and a third end of the first light-emitting control module is connected to the emission signal line, for controlling the communication between the first voltage source and the first end of the driving module; a first end of the second light-emitting control module is connected to the second end of the driving module, a second end of the second light-emitting control module is connected to the first end of the light-emitting module, and a third end of the second light-emitting control module is connected to the emission signal line, for controlling the communication between the second end of the driving module and the first end of the light-emitting module.

[0011] The adjustable capacitor module comprises a variable capacitor with a MOS capacitor structure.

[0012] To solve the above technical problems, another technical solution adopted by the present application is to provide a driving method of a pixel circuit, which is applied to the pixel circuit as described above, wherein the driving method comprises: in the data writing and threshold compensation stage, controlling the data writing module to be turned on, so as to transmit the data voltage to the first end of the adjustable capacitor module, and the adjustable capacitor module couples the data voltage to the control end of the driving module; and controlling the compensation module to be turned on, so as to charge the control end of the driving module, for compensating the threshold voltage of the driving module; in the light-emitting stage in the display period, controlling the first light-emitting control module and the second light-emitting control module to be turned on, so as to make the driving module drive the light-emitting module to emit light according to the voltages of the control end and the second end of the driving module.

[0013] To solve the above technical problems, the application adopts another technical solution: providing a display panel, wherein the display panel comprises a driving circuit and a pixel circuit connected with each other; wherein the pixel circuit is the pixel circuit according to any one of the above.

[0014] The application has the following advantages: different from the prior art, in the pixel circuit provided by the application, the first end of the driving module is connected with a first voltage source, the second end of the adjustable capacitor module is connected with the control end of the driving module, the first end of the adjustable capacitor module is connected with a second voltage source, so as to adjust the capacitance value of the adjustable capacitor module according to the output voltage of the second voltage source, the first end of the light-emitting module is connected with the second end of the driving module, and the second end of the light-emitting module is connected with a third voltage source, so that the pixel circuit can use the output voltage of the second voltage source required by a low capacitance value when high-frequency display is performed, that is, by adjusting the output voltage of the second voltage source, the capacitance value of the adjustable capacitor module is reduced, so as to reduce the charging time of the adjustable capacitor module and ensure the compensation effect; when low-frequency display is performed, the output voltage of the second voltage source required by a high capacitance value is used, so as to increase the capacitance value of the adjustable capacitor module, thereby ensuring that the light-emitting module is stable and does not flicker. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort, wherein:

[0016] Figure 1 is a structural schematic diagram of a first embodiment of the pixel circuit of the application;

[0017] Figure 2 is a structural schematic diagram of a second embodiment of the pixel circuit of the application;

[0018] Figure 3 is a structural schematic diagram of a specific embodiment of the pixel circuit in Figure 2

[0019] Figure 4 is a timing diagram of the control signal corresponding to the driving method of the pixel circuit in Figure 3

[0020] Figure 5 is a function diagram of the capacitance value of the adjustable capacitor module in the pixel circuit in Figure 3

[0021] Figure 6 is a diagram of the gray scale expansion simulation result of the pixel circuit in Figure 3 ​​​​

[0022] Figure 7 is a flowchart of an embodiment of a driving method of a pixel circuit of the present application;

[0023] Figure 8 is a structural diagram of an embodiment of a display panel of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0025] The terms “first”, “second”, “third” in the present application are only for descriptive purposes, 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”, “second”, “third” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “a plurality of” is at least two, such as two, three, etc., unless otherwise explicitly and specifically limited. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly. In addition, the terms “include” and “have” and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0026] In this document, the term “embodiment” means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it independent or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] The present application will be described in detail below in connection with the drawings and embodiments.

[0028] Please refer to Figure 1 , Figure 1is a structural schematic diagram of a pixel circuit first embodiment of the present application. In the present embodiment, the pixel circuit 10 comprises a driving module 11, an adjustable capacitance module 12 and a light emitting module 13.

[0029] It should be noted that in the field of display technology, the display panel usually continuously provides current to the light emitting module 13 in the pixel circuit 10 through a constant current source corresponding to the pixel circuit 10 output by the system power supply, wherein the size of the current is specifically adjusted and controlled by the control end voltage of the driving module 11 in the pixel circuit 10, and the control end voltage of the driving module 11 is written by the data signal corresponding to the pixel circuit 10 provided by the driving circuit of the display panel, so as to be stored in the adjustable capacitance module 12 in the pixel circuit 10, thereby ensuring that the light emitting module 13 can continuously emit light in a scanning period of the driving circuit to realize corresponding image display.

[0030] Specifically, the first end of the driving module 11 is connected to the first voltage source 101 provided by the system power supply, and the first voltage source 101 is specifically a constant current source.

[0031] The second end of the adjustable capacitance module 12 is specifically connected to the control end of the driving module 11, and the first end of the adjustable capacitance module 12 is connected to the second voltage source 102 corresponding to the system power supply or the driving circuit.

[0032] Among them, the output voltage of the second voltage source 102 is adjustable, and specifically is the system power supply or the corresponding adjustment of the driving circuit according to the current refresh frequency of the display panel, so as to be able to adjust the capacitance value of the adjustable capacitance module 12 according to the output voltage of the second voltage source 102, for example, when the display panel displays at high frequency, the output voltage of the second voltage source 102 is increased to reduce the capacitance value of the adjustable capacitance module 12; and when the display panel displays at low frequency, the output voltage of the second voltage source 102 is reduced to increase the capacitance value of the adjustable capacitance module 12.

[0033] Further, the first end of the light emitting module 13 is specifically connected to the second end of the driving module 11, and the second end of the light emitting module 13 is connected to the third voltage source 103 provided by the system power supply, so as to continuously emit light based on the output voltage corresponding to the driving module 11 and the third voltage source 103 in a scanning period of the driving circuit, so as to realize corresponding image display.

[0034] It is worth mentioning that for the display panel, the more the refresh times of the display panel displaying the image, the smaller the flicker of the image display, and the higher the picture quality. That is, the higher the refresh frequency of the display panel, the better the picture display, but at the same time, the more the energy consumption. Therefore, when high-quality picture is not required, the refresh frequency of the display panel is usually low, and when high-quality picture is required, the refresh frequency of the display panel is high, so as to balance the picture quality and energy consumption.

[0035] When the display panel works at high frequency (relatively high refresh frequency), the charging time of the adjustable capacitor module 12 is shortened, and the holding time required by the control end voltage of the driving module 11 is also shortened; when the display panel works at low frequency (relatively low refresh frequency), the charging time of the adjustable capacitor module 12 is lengthened, and the charging time required by the control end voltage of the driving module 11 is also lengthened.

[0036] Therefore, different refresh frequencies of the display panel have different requirements for the stability of the control end voltage of the driving module 11. By connecting an adjustable capacitor module 12 to the control end of the driving module 11 and making the capacitance value of the adjustable capacitor module 12 related to the refresh frequency of the display panel, the capacitance value of the adjustable capacitor module 12 can be changed when the refresh frequency of the display panel changes, so as to maintain the stability of the control end voltage of the driving module 11, meet the requirements of the current refresh frequency, and thus realize variable frequency display and meet different display requirements.

[0037] It can be understood that in order to meet the above requirements, that is, to shorten the charging time of the adjustable capacitor module 12 during high-frequency display to ensure compensation effect, and to ensure that the light-emitting module 13 is stable and does not flicker during low-frequency display, the output voltage of the second voltage source 102 is specifically positively related to the refresh frequency of the display panel and negatively related to the capacitance value of the adjustable capacitor module 12, that is, when the refresh frequency is higher, the output voltage of the second voltage source 102 is also higher, and the capacitance value of the adjustable capacitor module 12 is smaller.

[0038] The above scheme can effectively ensure the compensation effect by using the output voltage of the second voltage source 102 required by the low capacitance value of the pixel circuit 10 during high-frequency display, that is, by adjusting the output voltage of the second voltage source 102 to reduce the capacitance value of the adjustable capacitor module 12 to shorten the charging time of the adjustable capacitor module 12; and can effectively ensure that the light-emitting module 13 is stable and does not flicker by using the output voltage of the second voltage source 102 required by the high capacitance value of the pixel circuit 10 during low-frequency display to increase the capacitance value of the adjustable capacitor module 12.

[0039] In an embodiment, when the second voltage source 102 corresponds to at least two refresh frequencies of the pixel circuit 10, i.e. the corresponding display panel has at least two refresh frequencies, the second voltage source 102 also corresponds to at least two output voltages, and the adjustable capacitance module 12 also has at least two capacitance values corresponding to the at least two output voltages.

[0040] Specifically, the output voltage is positively correlated with the refresh frequency and negatively correlated with the capacitance value, i.e. when the refresh frequency is larger, the output voltage is also larger, and the capacitance value is smaller; and when the refresh frequency is smaller, the output voltage is also smaller, and the capacitance value is larger.

[0041] Further, in a specific embodiment, when the second voltage source 102 corresponds to a first refresh frequency of the pixel circuit 10, it corresponds to a first output voltage, and the adjustable capacitance module 12 has a first capacitance value corresponding to the first output voltage; and when the second voltage source 102 corresponds to a second refresh frequency of the pixel circuit 10, it corresponds to a second output voltage, and the adjustable capacitance module 12 has a second capacitance value corresponding to the second output voltage; wherein the first refresh frequency is specifically greater than the second refresh frequency, and the first output voltage is greater than the second output voltage, and the first capacitance value is smaller than the second capacitance value.

[0042] Optionally, the adjustable capacitance module 12 specifically can include a MOS capacitance structure, i.e. a variable capacitance in a metal layer-insulating layer-semiconductor layer mutual laminated structure, or other any reasonable structure type in which the capacitance value can change according to the plate voltage, which is not limited in the present application.

[0043] Please refer to Figure 2 , Figure 2 is a structural schematic diagram of the second embodiment of the pixel circuit provided in the present application. Based on the first embodiment of the pixel circuit provided in the present application, the pixel circuit 20 specifically further includes a compensation module 24.

[0044] Specifically, the first end of the compensation module 24 corresponds to the connection with the control end of the driving module 21, the second end of the compensation module 24 is connected with the second end of the driving module 21, and the third end of the compensation module 24 is correspondingly connected to the second scan line 202 in the display panel, for receiving the second scan signal provided by the second scan line 202 to the third end of the compensation module 24, and triggering the conduction under the action of the second scan signal, to control the communication between the control end of the driving module 21 and the second end of the driving module 21, so as to compensate the threshold voltage of the driving module 21, to avoid the change of the luminous brightness of the light-emitting module 23 due to the instability of the threshold voltage, and the serious non-uniformity of the light-emitting phenomenon.

[0045] In an embodiment, the pixel circuit 20 further comprises a first initialization module 251 and a second initialization module 252, and a first end of the first initialization module 251 is connected to a control end of the driving module 21, and a second end of the first initialization module 251 is connected to a first end of the second initialization module 252 and a reference voltage line 204 in the display panel, so that the first initialization module 251 and the second initialization module 252 can receive an initial voltage provided by the reference voltage line 204.

[0046] Further, a third end of the first initialization module 251 is connected to a first scan line 201, a second end of the second initialization module 252 is connected to a first end of the light emitting module 23, and a third end of the second initialization module 252 is also connected to the first scan line 201, the first initialization module 251 and the second initialization module 252 are used to receive a first scan signal provided by the first scan line 201, so as to write the initial voltage provided by the reference voltage line 204 to the second end of the adjustable capacitance module 22 and the first end of the light emitting module 23 under the action of the first scan signal, so as to initialize the adjustable capacitance module 22 and the light emitting module 23 at the same time, that is, to reset them to clear the signal residue that may exist in the previous stage.

[0047] In an embodiment, the pixel circuit 20 further comprises a data write module 26, and a first end of the data write module 26 is connected to a data line 203 in the display panel, so as to receive a data signal provided by the data line 203.

[0048] A second end of the data write module 26 is connected to a first end of the driving module 21, and a third end of the data write module 26 is connected to a second scan line 202, so as to receive a second scan signal provided by the second scan line 202, and when the data write module 26 is triggered to be turned on under the action of the second scan signal, the data voltage on the data line 203 is provided to the first end of the driving module 21, so as to be stored in the adjustable capacitance module 22, and then when the driving module 21 is triggered to be turned on, the data voltage is output to the light emitting module 23, so as to ensure that the light emitting module 23 continuously emits light in a scan period, so as to realize corresponding image display.

[0049] In an embodiment, the pixel circuit 20 further comprises a first light-emitting control module 271 and a second light-emitting control module 272. The first end of the first light-emitting control module 271 is connected to the first voltage source 101 provided by the system power supply. The second end of the first light-emitting control module 271 is connected to the first end of the driving module 21. The third end of the first light-emitting control module 271 is connected to the emission signal line 205 in the display panel, for receiving the emission signal provided by the emission signal line 205 and being triggered to conduct under the action of the emission signal, so as to control the first voltage source 101 to be in communication with the first end of the driving module 21.

[0050] The first end of the second light-emitting control module 272 is connected to the second end of the driving module 21. The second end of the second light-emitting control module 272 is connected to the first end of the light-emitting module 23. The third end of the second light-emitting control module 272 is also connected to the emission signal line 205, for receiving the emission signal provided by the emission signal line 205 and being triggered to conduct under the action of the emission signal, so as to control the second end of the driving module 21 to be in communication with the first end of the light-emitting module 23, thereby outputting the data voltage stored in the adjustable capacitor module 22 to the light-emitting module 23, so as to ensure that the light-emitting module 23 continuously emits light in one scanning period.

[0051] Optionally, the driving module 21, the compensation module 24, the first initialization module 251, the second initialization module 252, the data writing module 26, the first light-emitting control module 271, and the second light-emitting control module 272 can specifically include one of any reasonable switching devices such as a triode, a P-type thin-film transistor, an N-type thin-film transistor, and a field effect transistor, and the present application does not limit this.

[0052] It is worth noting that, in order to distinguish the two ends of the driving module 21 other than the control end, one pole is referred to as the first end, and the other pole is referred to as the second end. When the driving module 21 is a triode, the control end can specifically be a base, and the first end can be a collector, and the second end can be an emitter. Alternatively, the control end can also be a base, and the first end can be an emitter, and the second end can be a collector.

[0053] When the driving module 21 is a thin-film transistor or a field effect transistor, the control end can specifically be a gate, the first end can be a drain, and the second end can be a source. Alternatively, the control end can also be a gate, the first end can be a source, and the second end can be a drain.

[0054] The first end, the second end, and the third end of each module other than the driving module 21 correspond to the first end, the second end, and the control end of the driving module 21, respectively.

[0055] Wherein, when each module is a thin film transistor or a field effect transistor, it can also be a compound transistor or a single transistor, which is not limited in the present application.

[0056] For the convenience of understanding, taking the P-type thin film transistor as an example, it can be known that, please refer to Figure 3 and Figure 4 , wherein the Figure 3 is Figure 2 the structure diagram of a specific embodiment of the pixel circuit in Figure 4 , and Figure 3 the timing diagram of the control signal corresponding to the driving method of the pixel circuit in

[0057] It can be understood that, in the present embodiment, as shown in Figure 3 , the driving module 21, the compensation module 24, the first initialization module 251, the second initialization module 252, the data writing module 26, the first light-emitting control module 271 and the second light-emitting control module 272 can correspond to the first transistor T1, the third transistor T3, the fourth transistor T4, the seventh transistor T7, the second transistor T2, the fifth transistor T5 and the sixth transistor T6 respectively; and the adjustable capacitor module 22 corresponds to the variable capacitor Cst, and the light-emitting module 23 corresponds to the light-emitting device LED; and the first scan line 201, the second scan line 202, the data line 203, the reference voltage line 204 and the emission signal line 205 correspond to the first scan line Scan1, the second scan line Scan2, the data line Vdata, the reference voltage line Vref and the emission signal line EM respectively; the first voltage source 101, the second voltage source 102 and the third voltage source 103 correspond to the first voltage source Vdd, the second voltage source Vhd and the third voltage source Vss respectively; wherein the third transistor T3 and the fourth transistor T4 can be compound transistors, so as to reduce the requirement of the device on driving power, and the connection mode of each element is as shown in Figure 3 , which will not be described one by one.

[0058] As shown in Figure 4 , in the initialization stage, that is, in the t1 stage, the first scan signal provided by the first scan line Scan1 has a low level state, so as to control the fourth transistor T4 and the seventh transistor T7 to be triggered on, so as to write the initial voltage provided by the emission signal line EM into the variable capacitor Cst and the light-emitting device LED respectively, so as to initialize the variable capacitor Cst and the light-emitting device LED at the same time, that is, to reset the variable capacitor Cst and the light-emitting device LED, so as to clear the signal residue that may exist in the last stage.

[0059] Further, in the data writing and threshold compensation phase, i.e. in the t2 phase, the second scan signal provided by the second scan line Scan2 is in a low state, so as to control the second transistor T2 and the third transistor T3 to be triggered to be turned on, so as to transmit the data voltage provided by the data line Vdata to the first end of the variable capacitor Cst, and make the variable capacitor Cst couple the data voltage to the control end of the first transistor T1; and at the same time, the third transistor T3 charges the control end of the first transistor T1, so as to compensate the threshold voltage of the first transistor T1.

[0060] Further, in the light emitting phase in the display period, i.e. in the t3 phase, the emission signal provided by the emission signal line EM is in a low state, so as to control the fifth transistor T5 and the sixth transistor T6 to be triggered to be turned on, so as to make the first transistor T1 drive the light emitting device LED to emit light according to the voltages at the control end and the second end of the first transistor T1.

[0061] It can be understood that, as shown in Figure 5 , Figure 5 is Figure 3 a function diagram of the capacitance value of the adjustable capacitor module in the pixel circuit varying with the voltage; the variable capacitor Cst can be a MOS capacitor structure, so as to control the capacitance value of the variable capacitor Cst by the size of the output voltage of the second voltage source Vhd, so as to use the output voltage of the second voltage source Vhd with a low capacitance value in high-frequency display, so as to reduce the charging time and ensure the compensation effect; and use the output voltage of the second voltage source Vhd with a high capacitance value in low-frequency display, so as to ensure stable voltage without flickering.

[0062] Further, please continue to refer to Figure 6 , Figure 6 is Figure 3 a diagram of the gray scale expansion simulation result of the pixel circuit in

[0063] Therefore, according to the simulation result, under three different display frequencies of high, medium and low, the solution provided by the embodiment can work normally, and the gray scale expansion is normal, the current ratio is >1E6 in the Vdata range of 0-7V (the difference between the gate voltage values Vgs of the source-drain current Ids of the first transistor T1 corresponding to two luminance levels), which meets the switching ratio requirement of the light emitting device LED.

[0064] The application also provides a driving method of the pixel circuit, please refer to Figure 7 , Figure 7 is a flow diagram of an embodiment of the driving method of the pixel circuit. Specifically, it can include the following steps:

[0065] S31: in the data writing and threshold compensation stage, the data writing module is controlled to be turned on to transmit the data voltage to the first end of the adjustable capacitor module, the adjustable capacitor module couples the data voltage to the control end of the driving module, and the compensation module is controlled to be turned on to charge the control end of the driving module to compensate the threshold voltage of the driving module.

[0066] It can be understood that the driving method in the embodiment is a method for driving the pixel circuit as shown in the driving circuit in the corresponding display panel. Figure 2 Specifically, please refer to Figure 2 and Figure 4 and related text content, which will not be repeated here.

[0067] As shown in Figure 4 , in the data writing and threshold compensation stage, that is, in the t2 stage, the second scan signal provided by the second scan line has a low state to control the data writing module and the compensation module to be triggered to be turned on to transmit the data voltage provided by the data line to the first end of the adjustable capacitor module, so that the adjustable capacitor module couples the data voltage to the control end of the driving module; and at the same time, the compensation module charges the control end of the driving module to compensate the threshold voltage of the driving module.

[0068] S32: in the light emitting stage in the display period, the first light emitting control module and the second light emitting control module are controlled to be turned on to make the driving module drive the light emitting module to emit light according to the voltages at the control end and the second end of the driving module.

[0069] Further, in the light emitting stage in the display period, that is, in the t3 stage, the emission signal provided by the emission signal line has a low state to control the first light emitting control module and the second light emitting control module to be triggered to be turned on, so that the driving module drives the light emitting module to emit light according to the voltages at the control end and the second end of the driving module.

[0070] Further, in an embodiment, before S31, specifically, it can further include: an initialization stage, that is, in the t1 stage, the first scan signal provided by the first scan line has a low state to control the first initialization module and the second initialization module to be triggered to be turned on, so that the initial voltage provided by the emission signal line is written into the adjustable capacitor module and the light emitting module respectively to simultaneously initialize the adjustable capacitor module and the light emitting module, that is, to reset the adjustable capacitor module and the light emitting module to clear the signal residue that may exist in the last stage.

[0071] The application also provides a display panel, please refer to Figure 8 , Figure 8is a structural schematic diagram of an embodiment of the display panel of the present application. In the embodiment, the display panel 40 comprises a driving circuit 41 and a pixel circuit 42 connected to each other.

[0072] It should be noted that the pixel circuit 42 described in the embodiment is the pixel circuit 10 or the pixel circuit 20 described in any of the above embodiments, and details thereof can be referred to Figures 1-6 and related text contents, which will not be repeated here.

[0073] The beneficial effects of the present application are as follows: Different from the prior art, in the pixel circuit provided by the present application, the first end of the driving module is connected to the first voltage source, the second end of the adjustable capacitance module is connected to the control end of the driving module, the first end of the adjustable capacitance module is connected to the second voltage source, so as to adjust the capacitance value of the adjustable capacitance module according to the output voltage of the second voltage source, and the first end of the light-emitting module is connected to the second end of the driving module, and the second end of the light-emitting module is connected to the third voltage source, so that the pixel circuit can use the output voltage of the second voltage source required by the low capacitance value when displaying at high frequency, that is, by adjusting the output voltage of the second voltage source, the capacitance value of the adjustable capacitance module is reduced to reduce the charging time of the adjustable capacitance module, and the compensation effect is ensured; and when displaying at low frequency, the output voltage of the second voltage source required by the high capacitance value is used to increase the capacitance value of the adjustable capacitance module, so that the light-emitting module can be stabilized without flickering.

[0074] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation using the content of the specification and drawings of the present application, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A pixel circuit, characterized by comprising: The pixel circuit comprises: a driving module, a first end of the driving module being connected to a first voltage source; an adjustable capacitor module, a second end of the adjustable capacitor module being connected to a control end of the driving module, a first end of the adjustable capacitor module being connected to a second voltage source, so as to adjust a capacitance value of the adjustable capacitor module according to an output voltage of the second voltage source; a light-emitting module, a first end of the light-emitting module being connected to a second end of the driving module, a second end of the light-emitting module being connected to a third voltage source; a compensation module, a first end of the compensation module being connected to the control end of the driving module, a second end of the compensation module being connected to the second end of the driving module, and a third end of the compensation module being connected to a second scan line, for controlling the communication between the control end of the driving module and the second end of the driving module; a first initialization module and a second initialization module, a first end of the first initialization module being connected to the control end of the driving module, a second end of the first initialization module being connected to a first end of the second initialization module and a reference voltage line, a third end of the first initialization module being connected to a first scan line, a second end of the second initialization module being connected to the first end of the light-emitting module, and a third end of the second initialization module being connected to the first scan line, for controlling the writing of an initial voltage to the second end of the adjustable capacitor module and the first end of the light-emitting module; a data writing module, a first end of the data writing module being connected to a data line, a second end of the data writing module being connected to the first end of the driving module, and a third end of the data writing module being connected to the second scan line, for providing a data voltage on the data line to the first end of the driving module; a first light-emitting control module and a second light-emitting control module, a first end of the first light-emitting control module being connected to the first voltage source, a second end of the first light-emitting control module being connected to the first end of the driving module, and a third end of the first light-emitting control module being connected to an emission signal line, for controlling the communication between the first voltage source and the first end of the driving module; a first end of the second light-emitting control module being connected to the second end of the driving module, a second end of the second light-emitting control module being connected to the first end of the light-emitting module, and a third end of the second light-emitting control module being connected to the emission signal line, for controlling the communication between the second end of the driving module and the first end of the light-emitting module; wherein the second voltage source has at least two output voltages when the pixel circuit corresponds to at least two refresh frequencies, and the adjustable capacitor module has at least two capacitance values corresponding to the at least two output voltages; wherein the output voltage is positively correlated with the refresh frequency and negatively correlated with the capacitance value; the second voltage source has a first output voltage when the pixel circuit corresponds to a first refresh frequency, and the adjustable capacitor module has a first capacitance value corresponding to the first output voltage. The second voltage source has a second output voltage when the pixel circuit corresponds to a second refresh frequency, and the adjustable capacitance module corresponds to the second output voltage and has a second capacitance value; wherein the first refresh frequency is greater than the second refresh frequency, the first output voltage is greater than the second output voltage, and the first capacitance value is less than the second capacitance value.

2. The pixel circuit of claim 1, wherein, The adjustable capacitance module comprises a variable capacitance having a MOS capacitance structure.

3. A driving method of a pixel circuit, characterized by, The pixel circuit is applied in the pixel circuit of claim 1, comprising: In the data writing and threshold compensation phase, the data writing module is controlled to be turned on to transmit the data voltage to the first end of the adjustable capacitance module, and the adjustable capacitance module writes the data voltage to the control end of the driving module; and the compensation module is controlled to be turned on to charge the control end of the driving module to compensate the threshold voltage of the driving module; In the light emitting phase in the display period, the first light emitting control module and the second light emitting control module are controlled to be turned on to make the driving module drive the light emitting module to emit light according to the voltage of the control end and the second end thereof.

4. A display panel, characterized by, The display panel comprises a driving circuit and a pixel circuit connected thereto; The pixel circuit is any one of the pixel circuits of claims 1-2.

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