Patent Publication Number: US-11037488-B1

Title: Pixel driver circuit, display panel, display device, and driving method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority and benefit of China patent application No. 202010334607.9 filed on Apr. 24, 2020, the disclosure of which is hereby incorporated herein by reference in its entirety. 
     TECHNICAL HELD 
     Embodiments of the present disclosure relate to the field of display technologies and, in particular, to a pixel driver circuit, a display panel, a display device, and a driving method. 
     BACKGROUND 
     A current-driven display panel, such as an organic light emitting diode (OLED) display panel and a light emitting diode (LED) display panel, has many advantages, such as being all-solid-state, having wide viewing angle, having fast response and the like, and has great application prospects in the display field. 
     Each pixel unit of the current-driven display panel includes a pixel driver circuit and a light emitting element. The light emitting element is a current-driven piece, and the pixel driver circuit provides a driving current to the light emitting element. That is, the pixel driver circuit controls the luminance of the light emitting element by controlling the magnitude of the driving current. However, when different driving currents are used to drive light emitting elements of the same color, the luminous chromaticity of different light emitting elements may be different, thereby affecting the display effect of the display panel. For example, according to the image display requirements, the luminance of a red light emitting element A is LA, the luminance of a red light emitting element B is LB, where LA is not equal to LB. Then, if different driving currents are provided to the red light emitting element A and the red light emitting element B, the luminous chromaticity of the red light emitting element A and the luminous chromaticity of the red light emitting element B will be different from each other. 
     SUMMARY 
     The present disclosure provides a pixel driver circuit, a display panel, a display device, and a driving method to solve the problem that the display chromaticity of light emitting elements of the same color is different under different display brightness. 
     In a first aspect, an embodiment of the present disclosure provides a pixel driver circuit. The pixel driver circuit includes a data write module, a storage module, a first potential adjustment module, a second potential adjustment module, a comparison module, and a light emission control module. 
     The data write module is electrically connected to the first potential adjustment module at a first node. The storage module is electrically connected between the first node and a first level signal end. The first potential adjustment module is electrically connected between the first level signal end and a second node. The first potential adjustment module is electrically connected to the second potential adjustment module at the second node. The second potential adjustment module includes a potential pulse signal end, and the second node is electrically connected to a first input end of the comparison module. A second input end of the comparison module is in control of a reference signal. An output end of the comparison module is electrically connected to a control end of the light emission control module. 
     The data write module is configured to write a data signal into the first node at a first stage. The first potential adjustment module and the second potential adjustment module are configured to adjust a potential of the second node at a second stage, causing the comparison module to output a first control signal to the control end of the light emission control module based on the potential of the second node and the reference signal. The light emission control module is configured to control an output end of the light emission control module to be turned off according to the first control signal. 
     The first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node at a third stage, causing the comparison module to output a second control signal to the control end of the light emission control module based on the potential of the second node and the reference signal. The light emission control module is configured to output a driving signal through the output end of the light emission control module according to the second control signal. 
     In a second aspect, an embodiment of the present disclosure further provides a driving method for a display panel, the display panel including a plurality of the pixel driver circuits described in the first aspect, and the driving method including the following operations. 
     In S1, at a first stage, a data write module writes a data signal into the first node. 
     In S2, at a second stage, the first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node, causing the comparison module to output a first control signal to the control end of the light emission control module based on the potential of the second node and the reference signal, where the light emission control module is controlled by the first control signal, and the output end of the light emission control module is turned off. 
     In S3, at a third stage, the first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node, causing the comparison module to output a second control signal to the control end of the light emission control module based on the potential of the second node and the reference signal, where the light emission control module is controlled by the second control signal, and the output end of the light emission control module outputs a driving signal. 
     In a third aspect, an embodiment of the present disclosure further provides a display panel including a plurality of pixel units arranged in a matrix, where each of the plurality of pixel units includes a light emitting element and a pixel driver circuit described in the first aspect. 
     An output end of a light emission control module of the pixel driver circuit is electrically connected to an anode of the light emitting element. 
     In a fourth aspect, an embodiment of the present disclosure further provides a display device including the display panel described in the third aspect. 
     In the pixel driver circuit, the display panel, the display device, and the driving method provided by the embodiments of the present disclosure, the data write module, the storage module, the first potential adjustment module, the second potential adjustment module, the comparison module, and the light emission control module are disposed in the pixel driver circuit, where the data write module is electrically connected to the first potential adjustment module at the first node; the storage module is electrically connected between the first node and the first level signal end; the first potential adjustment module is electrically connected between the first level signal end and the second node; the first potential adjustment module is electrically connected to the second potential adjustment module at the second node; the second potential adjustment module includes the potential pulse signal end, and the second node is electrically connected to the first input end of the comparison module; the second input end of the comparison module is in control of the reference signal; the output end of the comparison module is electrically connected to the control end of the light emission control module; the data write module is configured to write the data signal into the first node at the first stage; the first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node at the second stage, causing the comparison module to output the first control signal to the control end of the light emission control module based on the potential of the second node and the reference signal; the light emission control module is configured to control the output end of the light emission control module to be turned off according to the first control signal; and the first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node at the third stage, causing the comparison module to output the second control signal to the control end of the light emission control module based on the potential of the second node and the reference signal; and the light emission control module is configured to output the driving signal through the output end of the light emission control module according to the second control signal, thereby achieving the drive control of the light emitting element. Since the longer the duty ratio of a light emitting duration of the light emitting element in one driving cycle (including the first stage, the second stage, and the third stage) of the pixel driver circuit, the greater the luminance displayed by the light emitting element, on the basis of providing a fixed driving current to each light emitting element, a pulse width modulation method may be used. That is, the duty ratio of the light emitting duration of the light emitting element is adjusted in one driving cycle (including the first stage, the second stage and the third stage) of a pixel driver circuit, so that the light emitting elements display different luminance. The duty ratio of the light emitting duration refers to a ratio of the light emitting duration of the light emitting element to the driving cycle of the pixel driver circuit in one driving cycle of the pixel driver circuit. Embodiments of the present disclosure solve the problem of deviation of both the chromaticity and the luminous efficiency of each light emitting element when the existing pixel driver circuit is driving, achieve regulation and control of the luminance of each light emitting element, and ensure consistency of luminous chromaticity and luminous efficiency of each light emitting element, thereby improving the display effect of the entire display panel. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a current drive characteristic curve of an existing current-driven Micro-LED light emitting element, 
         FIG. 2  is a graph illustrating the luminous efficiency of an existing current-driven light emitting element. 
         FIG. 3  is a block diagram of a pixel driver circuit according to an embodiment of the present disclosure. 
         FIG. 4  is a schematic diagram of a display panel according to an embodiment of the present disclosure. 
         FIG. 5  is a flowchart of a driving method for a display panel according to an embodiment of the present disclosure. 
         FIG. 6  is a schematic diagram of another pixel driver circuit according to an embodiment of the present disclosure. 
         FIG. 7  is a flowchart of another driving method for a display panel according to an embodiment of the present disclosure. 
         FIG. 8  is a control timing diagram of a driving signal of a pixel driver circuit shown in  FIG. 7 . 
         FIG. 9  is a graph illustrating the relationship between the potential of the second node and the output signal of the comparison module under different data signals according to an embodiment of the present disclosure. 
         FIG. 10  is another control timing diagram of a driving signal of a pixel driver circuit according to an embodiment of the present disclosure, 
         FIG. 11  is a schematic diagram of another display panel according to an embodiment of the present disclosure. 
         FIG. 12  is another control timing diagram of a driving signal in a driving method for a display panel according to an embodiment of the present disclosure. 
         FIG. 13  is a schematic diagram of a display device according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter the present disclosure will be further described in detail in connection with the drawings and embodiments. It is to be understood that the specific embodiments set forth herein are merely intended to illustrate rather than limit the present disclosure. Additionally, for ease of description, merely part, instead of all, of the structures related to the present disclosure are illustrated in the drawings. 
     As described in the previous Background section, in the existing current-driven display panel, a light emitting element has a fixed light emitting duration, a driving current is supplied to the light emitting element through a pixel driver circuit, and luminance of the light emitting element is controlled by the driving current.  FIG. 1  is a current drive characteristic curve of an existing current-driven Micro-LED light emitting element. Referring to  FIG. 1 , a luminous wavelength of the current-driven Micro-LED light emitting element decreases with the increase of the driving current, where the luminous wavelength represents luminous chromaticity of the light emitting element. In other words, for two Micro-LED light emitting elements of the same color, when different luminance is achieved by different driving currents, the luminous chromaticity may deviate due to different driving currents. Finally, the luminous chromaticity of the light emitting elements of the same color in the display panel is different under different luminance, resulting in uneven display chromaticity, thus affecting the display effect.  FIG. 2  is a graph illustrating the luminous efficiency of an existing current-driven light emitting element. Referring to  FIG. 2 , it may be known that the luminous efficiency of the current-driven light emitting element is related to the driving current, and when the driving current is small, the luminous efficiency of the light emitting element is low and varies greatly, which easily leads to instability of the luminous efficiency. 
     From the above, it may be known that the existing current-driven light emitting element has certain chromaticity deviation when driven with different driving currents due to its own luminous characteristics, and the luminous efficiency of the light emitting element is also affected by the driving currents. In view of the above problem, an embodiment of the present disclosure provides a pixel driver circuit. 
       FIG. 3  is a block diagram of a pixel driver circuit according to an embodiment of the present disclosure, Referring to  FIG. 3 , the pixel driver circuit includes a data write module  11 , a storage module  12 , a first potential adjustment module  13 , a second potential adjustment module  14 , a comparison module  15 , and a light emission control module  16 . The data write module  11  is electrically connected to the first potential adjustment module  13  at a first node  101 . The storage module  12  is electrically connected between the first node  101  and a first level signal end VGH. The first potential adjustment module  13  is electrically connected between the first level signal end VGH and a second node  102 . The first potential adjustment module  13  is electrically connected to the second potential adjustment module  14  at the second node  102 . The second potential adjustment module  14  farther includes a potential pulse signal end Sweep, and the second node  102  is electrically connected to a first input end  151  of the comparison module  15 . A second input end  152  of the comparison module  15  is controlled by a reference signal. An output end  153  of the comparison module  15  is electrically connected to a control end  161  of the light emission control module  16 . 
     The data write module  11  is configured to write a data signal into the first node  101  at a first stage. The first potential adjustment module  13  and the second potential adjustment module  14  are configured to adjust a potential of the second node  102  at a second stage, such that the comparison module  15  outputs a first control signal to the control end  161  of the light emission control module according to the potential of the second node  102  and the reference signal. The light emission control module  16  is configured to control an output end  162  of the light emission control module  16  to be turned off according to the first control signal. Additionally, the first potential adjustment module  13  and the second potential adjustment module  14  are configured to adjust the potential of the second node  102  at a third stage, such that the comparison module  15  outputs a second control signal to the control end  161  of the light emission control module  16  according to the potential of the second node  102  and the reference signal; and the light emission control module  16  is configured to output a driving signal through the output end  162  of the light emission control module  16  according to the second control signal. 
     The pixel driver circuit  10  shown in  FIG. 3  is correspondingly used to drive a light emitting element  20 , and the light emitting element  20  may be of a current-driven type, in which case the pixel driver circuit  10  outputs a driving current to the light emitting element  20  to drive the light emitting element  20  to emit light according to preset luminance. The light emission control module  16  in the pixel driver circuit  10  is used to control an on-off of a circuit where the light emitting element  20  is located by controlling an introduction of the driving current on the light emitting element  20 , so as to control the light emitting element  20  to emit light. The comparison module  15  outputs a signal for controlling the on-off to the light emission control module  16  according to a comparison result of a signal of the first input end  151  and a signal of the second input end  152 . The reference signal is input to the second input end  152  of the comparison module  15 , and the first input end  151  is electrically connected to the second node  102 . Two comparison signals provided by the first input end  151  and the second input end  152  of the comparison module  15  are derived from the potential of the second node  102  and a potential of the reference signal. In this way, according to the known reference signal, different control signals can be output from the comparison module  15  by reasonably controlling the potential of the second node  102  to control the on-off of the light emission control module  16 , thereby achieving a light emitting control of the light emitting element  20 . It could be understood that, in a case where power supply signals supplied to each of the light emitting elements  20  are guaranteed to be the same, a current when a circuit where the light emitting element  20  is turned on is the same, that is, driving currents supplied by each of the pixel driver circuits  10  to corresponding light emitting elements  20  is consistent, such that the luminous chromaticity and the luminous efficiency of each of the light emitting elements  20  can be guaranteed to be consistent. However, in order to control light emitting elements  20  at different positions to achieve different luminance such that the display panel achieves different display pictures, the duty ratio of the light emitting duration of the light emitting element  20  may be adjusted. The longer the duty ratio of the light emitting duration of the light emitting element in one driving cycle (including the first stage, the second stage, and the third stage) of the pixel driver circuit, the greater the luminance. 
     As described above, by utilizing the potential of the second node  102 , the on-off of the light emission control module  16  may be controlled, thereby controlling the light emitting duration of the light emitting element  20 . 
     The potential of the second node  102  may be adjusted by the first potential adjustment module  13  and the second potential adjustment module  14 , As can be seen from the circuit between the first level signal end VGH and the potential pulse signal end Sweep, the potential of the second node  102  will have a potential V 2 , where V 2 =V sweep +(V GH −V sweep )/(R 2 +R 3 )*R 3 , and R 2  and R 3  are resistances of the first potential adjustment module  13  and the second potential adjustment module  14 , respectively. In this way, in the circuit between the first level signal end VGH and the potential pulse signal end Sweep, the potential V 2  of the second node  102  is substantially dependent on a resistance ratio of the first potential adjustment module  13  and the second potential adjustment module  14 . By reasonably controlling and adjusting resistances of the first potential adjustment module  13  and the second potential adjustment module  14 , adjustment and control of the potential of the second node  102  may be achieved. 
     The first potential adjustment module  13 , the storage module  12  and the data write module  11  are connected to the first node  101 , where the data write module  11  is used for writing the data signal to the first node  101 , and the storage module  12  is used for storing the data signal written by the data write module  11 , so as to adjust the resistance of the first potential adjustment module  13  in a suitable time period. On the condition that the variation trend of the resistance of the second potential adjustment module  14  is known or the variation trend of the resistance of the second potential adjustment module  14  is controlled, the data signal can be used to achieve regulation and control of the second node  102 , and further, the control of the light emitting duration of the light emitting element  20  can be achieved by the comparison module  15  and the light emission control module  16 . Therefore, in the pixel driver circuit provided by the embodiment of the present disclosure, a pulse width modulation method may be used in a case where the driving current is fixed during the light emission duration of light emitting element  20  to adjust the duty ratio of the light emitting duration of a corresponding light emitting element  20  through the data signal, That is, the duty ratio of the light emitting duration of the light emitting element is adjusted in one driving cycle (including the first stage, the second stage and the third stage) of a pixel driver circuit, such that the light emitting element displays different luminance. 
     It is to be noted that in the embodiment of the present disclosure, in order to facilitate illustration of a structure and signal of the pixel driver circuit and simply the description, part of signal ends and signals on the part of signal ends are represented by the same symbol. As illustrated in  FIG. 3 , the first level signal end of the first potential adjustment module  13  and a level signal thereof are represented by VGH, and the potential pulse signal end of the second potential adjustment module  14  and the potential adjustment pulse signal thereof are represented by Sweep, Additionally, the light emission control module  16  and the light emitting element  20  are substantially connected to a first power supply signal end and a second power supply signal end, and therefore both the first power supply signal end and a first power supply signal thereof are represented by PVDD, and both the second power supply signal end and a second power supply signal thereof are represented by PVEE. 
     Based on the above-described pixel driver circuit, an embodiment of the present disclosure further provides a display panel.  FIG. 4  is a structural diagram of a display panel according to an embodiment of the present disclosure. Referring to  FIG. 3  and  FIG. 4 , the display panel includes a plurality of pixel units  100  arranged in a matrix, where each of the plurality of pixel units  100  includes a light emitting element  20  and any one of the pixel driver circuits  10  provided by the embodiment of the present disclosure, and the output end  162  of the light emission control module  16  of the pixel driver circuit  10  is electrically connected to an anode  21  of the light emitting element  20 . The pixel driver circuit  10  is used for supplying the driving signal to the light emitting element  20  through the light emission control module  16  to control the light emitting element  20  to emit light, such that each pixel unit  100  in the display panel is displayed to form a display picture. 
     It could be understood that, in the above-mentioned display panel, the pixel units  100  are arranged in the matrix, and therefore the pixel driver circuits  10  in the pixel units  100  are arranged in a plurality of rows and columns. The working process and principle of the pixel driver circuit and the display panel provided by the embodiments of the present disclosure will be described below.  FIG. 5  is a flowchart of a driving method for a display panel according to an embodiment of the present disclosure. Referring to  FIG. 3  to  FIG. 5 , the driving method includes the steps described below. 
     In S1, at the first stage, the data write module writes the data signal into the first node. 
     This stage is essentially a data writing stage, and the pixel driver circuit  10  stores the data signal. 
     In S2, at the second stage, the first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node, causing the comparison module to output the first control signal to the control end of the light emission control module based on the potential of the second node and the reference signal, where the light emission control module is controlled by the first control signal, and the output end of the light emission control module is turned off. 
     In this stage, in the case where the potential pulse signal end. Sweep of the second potential adjustment module  14  is known, the resistance of the second potential adjustment module  14  can be determined. At the same time, on the basis that the first level signal end VGH of the first potential adjustment module  13  is known, the resistance of the first potential adjustment module  13  may be adjusted through the data signal stored in the first node  101 , thereby achieving adjustment of the potential of the second node  102 . Adjusted potential of the second node  102  is input to the first input end  151  of the comparison module  15 , and the comparison module  15  outputs a signal. That is, the first control signal compares the potential of the second node of the first input end  151  with the reference signal of the second input end  152  to control the light emission control module  16  to turn off. At this time, the circuit where the light emitting element  20  is located is turned off, and the light emitting element  20  remains in an off state. 
     In S3, at the third stage, the first potential adjustment module and the second potential adjustment module are configured- to adjust the potential of the second node, causing the comparison module to output the second control signal to the control end of the light emission control module based on the potential of the second node and the reference signal, where the light emission control module is controlled by the second control signal, and the output end of the light emission control module outputs the driving signal. 
     Similarly, in this stage, on the basis that signals of the first level signal end VGH of the first potential adjustment module  13  and the potential pulse signal end Sweep of the second potential adjustment module  14  are known, the potential of the second node  102  can be regulated and controlled by utilizing the data signal stored in the first node  101 , such that the signal at the first input end  151  of the comparison module  15  changes, and then the comparison module  15  outputs the second control signal for controlling the light emission control module  16  to turn on and output the driving signal in this stage. It is to be noted that, in order to ensure that the output of the comparison module  15  at the third stage varies from the output of the comparison module  15  at the second stage, the potential V 2  of the second node needs to be reasonably adjusted such that the potential V 2  of the second node changes from being greater than the reference signal Vref of the comparison module  15  at the second stage to being smaller than the reference signal of the comparison module  15 , or changes from being smaller than the reference signal Vref of the comparison module  15  at the second stage to being greater than the reference signal Vref of the comparison module  15 . 
     From the above driving process of the pixel driver circuit and the display panel, it can be seen that, at the third stage, the light emitting element  20  emits light by the driving signal supplied by the pixel driver circuit  10 , and a time length of the third stage determines the light emitting duration of the light emitting element  20 , that is, determines the luminance of the light emitting element  20 . Therefore, on the basis of the signals input by the first level signal end VGH and the potential pulse signal end Sweep in each pixel driver circuit, by reasonably setting the data signal input and stored by the first node  101 , each light emitting element  20  can be controlled to emit light, and the luminance of each light emitting element  20  can be regulated and controlled, thereby achieving the image display of the entire display panel. 
     In the pixel driver circuit provided by the embodiments of the present disclosure, the data write module, the storage module, the first potential adjustment module, the second potential adjustment module, the comparison module and the light emission control module are disposed. The data write module is electrically connected to the first potential adjustment module at the first node. The storage module is electrically connected between the first node and the first level signal end. The first potential adjustment module is electrically connected between the first level signal end and the second node. The first potential adjustment module is electrically connected to the second potential adjustment module at the second node. The second potential adjustment module includes the potential pulse signal end, and the second node is electrically connected to the first input end of the comparison module. The second input end of the comparison module is controlled by the reference signal. The output end of the comparison module is electrically connected to the control end of the light emission control module. The data write module is configured to write the data signal into the first node at the first stage. The first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node at the second stage, causing the comparison module to output the first control signal to the control end of the light emission control module based on the potential of the second node and the reference signal. The light emission control module is configured to control the output end of the light emission control module to be turned off according to the first control signal; and the first potential adjustment module and the second potential adjustment module are configured to adjust the potential of the second node at the third stage, causing the comparison module to output the second control signal to the control end of the light emission control module based on the potential of the second node and the reference signal. The light emission control module is configured to output the driving signal through the output end of the light emission control module according to the second control signal. In this way, a drive control of the light emitting element is achieved, and, on the basis of providing the fixed driving current to each light emitting element, the pulse width modulation method may be used, that is, the duty ratio of the light emitting duration of the light emitting element is adjusted in one driving cycle (including the first stage, the second stage and the third stage) of a pixel driver circuit, such that the light emitting elements display different luminance. The embodiments of the present disclosure solve the problem that both the chromaticity and the luminous efficiency may deviate when the existing pixel driver circuit is driving, achieve regulation and control of the luminance of each light emitting element, and ensure consistency of the luminous chromaticity and the luminous efficiency of each light emitting element, thereby improving the display effect of the entire display panel. 
     An embodiment of the present disclosure provides a specific pixel driver circuit for each circuit module of the pixel driver circuit provided by the above-mentioned embodiment.  FIG. 6  is a schematic diagram of another pixel driver circuit according to an embodiment of the present disclosure. Referring to  FIG. 6 , in the pixel driver circuit, the data write module  11  includes a first transistor  111 ; the storage module  12  includes a first capacitor  121 ; the first potential adjustment module  13  includes a second transistor  12 ; a first electrode  1111  of the first transistor  111  is used for acquiring the data signal; a second electrode  1112  of the first transistor  111  is electrically connected to the first node  101 ; a gate  1113  of the first transistor  111  is controlled by a scan signal; a first plate  1211  of the first capacitor  121  is electrically connected to the first node  101 ; a second plate  1212  of the first capacitor  121  is electrically connected to the first level signal end VGH; a gate  1123  of the second transistor  112  is electrically connected to the first node  101 ; a first electrode  1121  of the second transistor  112  is electrically connected to the first level signal end VGH; and a second electrode  1122  of the second transistor  112  is electrically connected to the second node  102 . 
     The first transistor  111  is turned on and off by the scan signal of the gate  1113 , thereby inputting the data signal of the first electrode  1111  to the first node  101  when turned on. Since the first node  101  is electrically connected to the first plate  1211  of the first capacitor  121 , the process of writing the data signal into the first node  101  is essentially a process of storing charges in the first capacitor  121 , that is, the first capacitor  121  achieves storage of the data signal. The second transistor  112 , that is, the first potential adjustment module  13 , is used to adjust the resistance of the second transistor  112  according to the control of the driving signal, thereby adjusting the potential of the second node  102 . From a transistor resistance formula 
                 R     o   ⁢   n       =     1       μ   n     ⁢     C   ox     ⁢     W   L     ⁢     (       V   GS     -     V   TH       )           ,         
it can De seen that a resistance value of the second transistor  112  mainly depends on a gate-source voltage value VGS, which is a voltage value of a source. That is, the first electrode  1121  of the second transistor  112  depends on the level signal of the first level signal end VGH, and a voltage value of the gate  1123  of the second transistor  112  depends on the potential of the first node  101 , that is, the data signal stored in the first capacitor  121 . In this way, the resistance value of the first potential adjustment module  13  may be adjusted by the data signal held by the first node  101 .
 
     Still referring to  FIG. 6 , the second potential adjustment module  14  may be configured to include a third transistor  113 , where a gate  1133  of the third transistor  113  is electrically connected to the first level signal end VGH, a first electrode  1131  of the third transistor  113  is used for acquiring a potential adjustment pulse signal Sweep, and a second electrode  1132  of the third transistor  113  is electrically connected to the second node  102 . 
     Similarly, the third transistor  113 , that is, the second potential adjustment module  14 , is also used to adjust its own resistance according to the control of the driving signal, and thereby to adjust the potential of the second node  102 . From the transistor resistance formula 
                 R     o   ⁢   n       =     1       μ   n     ⁢     C   ox     ⁢     W   L     ⁢     (       V   GS     -     V   TH       )           ,         
it can De seen that the resistance value of the third transistor  113  mainly depends on the gate-source voltage value, that is, the level signal of the first level signal end VGH and the potential adjustment pulse signal Sweep received by the first electrode  1131  form the gate-source voltage of the third transistor  113 . The resistance value of the second potential adjustment module  14  can be adjusted by reasonably setting the level signal of the first level signal end VGH and the potential adjustment pulse signal Sweep received by the first electrode  1131 .
 
     Still referring to  FIG. 6 , the comparison module  15  in the pixel driver circuit may optionally include a comparator  131 , where a positive phase input end  1311  of the comparator  131  is the first input end  151  of the comparison module  15 ; an inverting input end  1312  of the comparator  131  is the second input end  152  of the comparison module  15 ; a first power supply end  1313  of the comparator  131  is electrically connected to the first level signal end VGH, and a second power supply end  1314  of the comparator  131  is electrically connected to a second level signal end VGL. 
     The first power supply end  1313  and the second power supply end  1314  supply power to the comparator  131  according to electrical signals supplied by the first level signal end VGH and the second level signal end VGL. An output of the comparator  131  can be controlled by inputting different signals to the positive phase input end  1311  and the inverting input end  1312  of the comparator  131 . Generally, an output level of the comparator  131  will jump when a magnitude relationship between the two input signals changes, and a rising edge or falling edge of an output waveform is easily delayed during the jump, resulting in an arc-shaped waveform. 
     Based on this, still referring to  FIG. 6 , in the pixel driver circuit provided by the embodiment of the present disclosure, optionally, the comparison module  15  further includes an inverter unit  140 ; an output end  1315  of the comparator  131  is electrically connected to an input end  1401  of the inverter unit  140 ; an output end  1402  of the inverter unit  140  is the output end  153  of the comparison module  15 ; and the inverter unit  140  includes at least one inverter  141  connected in sequence. At this time, at least one inverter  141  connected in sequence can adjust the waveform output by the comparator  131  such that the output waveform is more neat, thereby more accurately controlling the on-off of the light emission control module and ensuring light emission of the light emitting element and accurate control of the light emitting duration. As illustrated in  FIG. 6 , two inverters  141  may be disposed in the inverter unit  140 , and at this time, an output signal level state of the comparison module  15  coincides with an output signal level state of the comparator  131 . 
     Still referring to  FIG. 6 , optionally, the light emission control module  16  includes a fourth transistor  114 , where a gate  1143  of the fourth transistor  114  is the control end  161  of the light emission control module  16 , a first electrode  1141  of the fourth transistor  114  is electrically connected to a first power supply signal end PVDD, and a second electrode  1142  of the fourth transistor  114  is the output end  162  of the light emission control module  16 . 
     The fourth transistor  114  may be selected as an N-type transistor or a P-type transistor, and the level signal output from the comparison module  15  can control the on-off of the fourth transistor  114 , that is, the light emission control module  16 . As illustrated in  FIG. 6 , the fourth transistor  114  is described as a P-type transistor as an example. At the second stage of the driving process of the pixel driver circuit, the first control signal output by the comparison module  15  is substantially a high level signal, and at this time, the fourth transistor  114  is turned off and the light emitting element  20  remains in the off state. At the third stage of the driving process of the pixel driver circuit, the second control signal output by the comparison module  15  is substantially a low level signal, and at this time, the fourth transistor  114  is turned on and the light emitting element  20  emits light. The fourth transistor  114  and the light emitting element  20  are connected between the first power supply signal end PVDD and the second power supply signal end PVEE, the first power supply signal PVDD and the second power supply signal PVEE supply power to the light emitting element  20 , and the fourth transistor  114  is substantially responsible for the on-off of the circuit. Thus, driving currents of light emitting elements  20  corresponding to each pixel driver circuit of the display panel are consistent, so that the luminous chromaticity and the luminous efficiency of each light emitting element  20  may be kept the same. 
     In the pixel driver circuit illustrated in  FIG. 6 , the first transistor  111 , the second transistor  112 , and the third transistor  113  are N-type transistors, and the fourth transistor  114  is the P-type transistor, for example. In other embodiments of the present disclosure, the first transistor  111 , the second transistor  112 , and the third transistor  113  may further be set as the P-type transistors, and the fourth transistor  114  may be the N-type transistor. Furthermore, types of the first transistor  111 , the second transistor  112 , the third transistor  113 , and the fourth transistor  114  may be the same or different, which will not be limited herein. 
     Specifically, as illustrated in  FIG. 6 , in the pixel driver circuit, the data write module  11  includes the first transistor  111 ; the storage module  12  includes the first capacitor  121 ; the first potential adjustment module  13  includes the second transistor  12 ; the first electrode  1111  of the first transistor  111  is used for acquiring the data signal; the second electrode  1112  of the first transistor  111  is electrically connected to the first node  101 ; the gate  1113  of the first transistor  111  is controlled by the scan signal; the first plate  1211  of the first capacitor  121  is electrically connected to the first node  101 ; the second plate  1212  of the first capacitor  121  is electrically connected to the first level signal end VGH; the gate  1123  of the second transistor  112  is electrically connected to the first node  101 ; the first electrode  1121  of the second transistor  112  is electrically connected to the first level signal end VGH; and the second electrode  1122  of the second transistor  112  is electrically connected to the second node  102 . The second potential adjustment module  14  includes the third transistor  113 , where the gate  1133  of the third transistor  113  is electrically connected to the first level signal end VGH, the first electrode  1131  of the third transistor  113  is used for acquiring the potential adjustment pulse signal Sweep, and the second electrode  1132  of the third transistor  113  is electrically connected to the second node  102 . Based on this, an embodiment of the present disclosure further provides a driving method for a display panel. The driving method for the display panel will be described below with an example that the first transistor, the second transistor and the third transistor are N-type transistors and the fourth transistor is the P-type transistor. 
       FIG. 7  is a flowchart of another driving method for a display panel according to an embodiment of the present disclosure.  FIG. 8  is a control timing diagram of a driving signal of a pixel driver circuit shown in  FIG. 7 . Referring to  FIG. 6  to  FIG. 8 , in the driving method, step S1 includes a step described below. At the first stage t 1 , the first transistor  111  writes the data signal to the first node  101 . 
     The scan signal ROW input to the gate  1113  of the first transistor  111  is a high level signal at the first stage t 1 . At this time, the first transistor  111  is turned on, and the first electrode  1111  of the first transistor  111  receives the data signal, so that the data signal is written to the first node  101 . 
     Step S2 includes the steps described below. At the second stage t 2 , the second transistor  112  and the third transistor  113  adjust the potential of the second node  102 , such that the potential of the second node  102  is greater than the reference signal Vref, the comparison module  15  outputs the first control signal, and the light emission control module  16  is turned off. 
     A process of adjusting the potential of the second node  102  by the second transistor  112  and the third transistor  113  is essentially a process of changing the resistances of the second transistor  112  and the third transistor  113 , and the resistances of the second transistor  112  and the third transistor  113  can be adjusted by changing gate-source voltage values of the second transistor  112  and the third transistor  113 . As can be seen from  FIG. 6 , the potential of the first node  101  and signals of the first level signal end and the potential pulse signal end determine the resistances of the second transistor  112  and the third transistor  113 , that is, the potential of the second node  102 . Further, the first level signal VGH as a fixed level signal is described as an example, and the potential of the second node  102  depends on the potential adjustment pulse signal Sweep. As shown in  FIG. 8 , the waveform of the potential adjustment pulse signal Sweep acquired by the second potential adjustment module  14  may be selected as a sawtooth wave, Apparently, when the potential adjustment pulse signal Sweep is a sawtooth wave with a downward trend, the potential of the second node  102  also shows a downward trend following the potential adjustment pulse signal Sweep, By reasonably setting the data signal input and stored by the first node  101 , it can be satisfied that the potential of the second node  102  is greater than the reference signal Vref at the second stage t 2 , so that the comparison module  15  outputs the high level signal, that is, the first control signal, to control the fourth transistor  114  to turn off. 
     For the pixel driver circuit illustrated in  FIG. 6 , the potential V 2  of the second node under different data signals and the output signal Vout of the comparison module are experimentally investigated in the embodiment of the present disclosure. The data signal data adopts 0V, 1V, 2V, 3V, 4V and 5V, respectively.  FIG. 9  is a graph illustrating a relationship between a potential of a second node and an output signal of a comparison module under different data signals according to an embodiment of the present disclosure. Referring to  FIG. 6 ,  FIG. 8  and  FIG. 9 , firstly, the data signal data as 0V is described as an example. The potential V 2  of the second node  102  is controlled by the resistance of the second transistor  112 , and the potential V 2  of the second node  102  keeps a consistent variation trend with the potential adjustment pulse signal Sweep and presents the sawtooth waveform. At the first stage t 1  and the second stage t 2 , the potential V 2  of the second node  102  is at a high potential and continues to fall, but is still greater titan the reference signal Vref, Apparently, at the first stage t 1  and the second stage t 2 , when a voltage value of the positive phase input end  1311  of the comparator  131  is greater than a voltage value of the inverting input end  1312 , the comparator  131  outputs a high level, and an output signal Vout, after passing through two inverters  141 , remains at a high level. For the fourth transistor  114  of the P-type, at this time, the gate is input a high level, the transistor is turned off and the light emitting element is in the off state. 
     Step S3 includes the steps described below. At the third stage t 3 , the second transistor  112  and the third transistor  113  adjust the potential of the second node  102 , such that the potential of the second node  102  is less than the reference signal Vref, the comparison module  15  outputs the second control signal, and the light emission control module  16  outputs the driving signal. 
     Referring to  FIG. 7  and  FIG. 8 , still taking the data signal data as 0V for example, at the third stage t 3 , the potential adjustment pulse signal Sweep continues to fall, so that the potential V 2  of the second node  102  can continue to fall through the third transistor  113 , and the potential V 2  of the second node  102  is lower than the reference signal Vref. At this time, the voltage value of the positive phase input end  1311  of the comparator  131  is greater than the voltage value of the inverting input end  1312 , the comparator  131  outputs a low level, and the output signal Vout, after passing through the two inverters  141 , remains at the low level. For the fourth transistor  114  of the P-type, at this time, the gate is input the low level, the transistor is turned on, and the driving current is supplied to the light emitting element from the output end to drive the light emitting element to emit light. 
     Still referring to  FIG. 9 , when the potential V 2  of the second node is greater than the reference signal V ref , the pixel driver circuit is at the first stage t 1  and the second stage t 2 ; and when the potential of the second node is less than the reference signal Vref, the pixel driver circuit is at the third stage t 3 . Furthermore, when the potential V 2  of the second node falls equal to the reference signal Vref, the sawtooth waveform of the potential V 2  of the second node intersects the reference signal Vref, and an abscissa of an intersecting point is a time junction point of the second stage t 2  and the third stage t 3 . 
     When the data signal data is 0V to 5V respectively, the potential V 2  of the second node is compared with the output signal Vout of the comparison module, and it can be seen that the potential V 2  of the second node  102  mainly depends on the potential adjustment pulse signal Sweep, but is also affected by the data signal data at the same time, By changing the value of the data signal data, the potential of the second node  102  will change accordingly, which in turn causes a level jump time node of the output signal Vout of the comparison module to be different. Specifically, when the data signal data changes from 0V to 5V, the potential V 2  of the second node rises accordingly, and as illustrated in  FIG. 9 , the sawtooth waveform of the potential V 2  of the second node moves up as a whole. In the case where the reference signal Vref remains unchanged, the intersection point of the potential V 2  of the second node and the reference signal Vref moves in an abscissa direction, and a corresponding time junction point of the second stage t 2  and the third stage t 3  moves backward, That is, when the value of the data signal data is appropriately increased, the time length of the third stage t 3  can be correspondingly reduced, the light emitting duration of the light emitting element is reduced, and the luminance of the light emitting element is reduced. On this basis, those skilled in the art can adjust the time junction point of the second stage t 2  and the third stage t 3  by reasonably setting the reference signal and the value of the data signal, so as to control a proportion of the light emitting duration of the light emitting element and further control the luminance of the light emitting element. When the time length of the third stage t 3  is 0, the light emitting element remains in the off state in the whole image display cycle, so the pixel unit is at a lowest gray scale. When the pixel driver circuit directly enters the third stage t 3  after passing through the first stage t 1 , the time length of the second stage t 2  is 0, the time length of the third stage t 3  is the largest, and the luminance of the light emitting element is the brightest in the whole image display cycle, which corresponds to a highest gray scale of the pixel unit. 
       FIG. 10  is another control timing diagram of a driving signal of a pixel driver circuit according to an embodiment of the present disclosure. Referring to  FIG. 6  and  FIG. 10 , in the pixel driver circuit in the embodiment of the present disclosure, optionally, the potential adjustment pulse signal Sweep acquired by the second potential adjustment module  14  is a constant voltage signal at the first stage t 1 . This stage is mainly used to write the data signal into the first node  101 , so the first potential adjustment module  13  and the second potential adjustment module  14  do not need to be adjusted. 
     On the basis of the pixel driver circuit and the display panel provided in the above-mentioned embodiment, potential adjustment pulse signal ends Sweep in each pixel driver circuit  10  may be optionally electrically connected. At this time, a same potential adjustment pulse signal Sweep is provided at the potential adjustment pulse signal end Sweep of each pixel driver circuit  10 , and a suitable data signal is only input into to the input end of the data write module to control the luminance of each light emitting element.  FIG. 11  is a schematic diagram of another display panel according to an embodiment of the present disclosure. Referring to  FIG. 6  and  FIG. 11 , specifically, the display panel may be configured to include a plurality of potential pulse signal lines Sweep in parallel; the plurality of pixel driver circuits  10  in the display panel are arranged in the plurality of rows and columns; potential pulse signal ends Sweep of a same row of pixel driver circuits  10  are connected to a same potential pulse signal line Sweep; and each potential pulse signal line Sweep is electrically connected. Of course, those skilled in the art may further configure the potential pulse signal ends Sweep of pixel driver circuits  10  of a same column to be connected to a same potential pulse signal line Sweep, and each potential pulse signal line Sweep to be electrically connected, which is not limited herein. 
     Referring to  FIG. 6  and  FIG. 11 , exemplarily, the display panel may include n rows and m columns of pixel units  100 , where gates  1113  of first transistors  111  of each row of pixel driver circuits  10  are electrically connected to a same scan signal line Gout. For example, when n is 240, the display panel includes 240 scan signal lines Gout. Meanwhile, first electrodes  1111  of first transistors  111  in each column of the pixel driver circuits  10  are electrically connected to the same data signal line (not shown in the figure). The pixel driver circuit  10  in each pixel unit  100  provides the scan signal through the scan signal line Gout at the first stage and when the scan signal jumps to the high level, the first transistor  111  is turned on. The data signal on the data signal line is written into and stored in the first node  101  in the pixel driver circuit  10  through the first transistor  111 . 
     On this basis, an embodiment of the present disclosure further provides a driving method for a display panel.  FIG. 12  is another control timing diagram of a driving signal in a driving method for a display panel according to an embodiment of the present disclosure. Referring to  FIG. 6 ,  FIG. 11  and  FIG. 12 , each row of scan signal lines provides the scan signal Gout. When the level of the scan signal Gout jumps to the high level, the first transistor  111  is turned on, and the row of pixel driver circuits  10  writes the data signal into the first node  101  in advance. Therefore, when the scan signal Gout is the high level signal, the pixel driver circuit of the corresponding row is at the first stage t 1  of data writing. The plurality of pixel driver circuits in the display panel provided by the embodiment of the present disclosure are arranged in the plurality of rows and columns. In the driving method provided by the above-mentioned embodiment, the pixel driver circuit  10  of each row of pixel units  100  may execute the third stage t 3  after the first stage t 1  of each row pixel driver circuit  10  is completed in the image display cycle of one frame. That is, each row pixel driver circuit  10  in the display panel may write the data signal into the first node  101  in advance through the first stage t 1 . After all the pixel driver circuits  10  of the whole display panel complete the first stage t 1 , the second node  102  of each pixel driver circuit  10  can be adjusted by using the written data signal and the continuously falling potential adjustment pulse signal Sweep, such that the potential V 2  of the second node at this time is lower than the voltage of the reference signal Vref, thereby driving each pixel driver circuit  10  to execute the third stage t 3 . Of course, between the first stage t 1  and the third stage t 3 , the potential V 2  of the second node is still maintained at a voltage greater than the reference signal Vref, so that the pixel driver circuit  10  at this time is substantially at the second stage t 2 , the comparison module outputs the first control signal, and the light emitting element is in the off state. 
     It is to be noted that, still referring to  FIG. 12 , the first stage t 1  of each pixel driver circuit  10  in the whole display panel is a stage of data signal writing, which is essentially a stage in which the scan signal on the corresponding scan signal line Gout is in a high level state, and at this time, the first transistor  10  in the pixel driver circuit  10  is turned on by the control of the high level scan signal, while the data signal lines in the column provide the data signal, so that the data signal can be written into the first node  101  of the pixel driver circuit  10 . 
     An embodiment of the present disclosure further provides a display device.  FIG. 13  is a schematic diagram of a display device according to an embodiment of the present disclosure, Referring to  FIG. 13 , the display device includes any one of the display panels  1  provided by the embodiments of the present disclosure. The liquid crystal display device may specifically be a mobile phone, a computer, a smart wearable apparatus and so on. 
     The foregoing merely depict some illustrative embodiments according to the present disclosure and the technical principles used herein. Those skilled in the art will appreciate that the present disclosure will not be limited to the specific embodiments described herein, and they will also be able to make various apparent modifications, adaptations, combinations and substitutions without departing from the scope of the present disclosure. Therefore, while the present disclosure has been described in detail through the foregoing embodiments, the present disclosure will not be limited to the above-described embodiments and may further include many other equivalent embodiments without departing from the concept of the present disclosure. The scope of the present disclosure is thus only determined in and by the appended