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 light-emitting module, a driving module, a coupling module, a second voltage transmission unit and a voltage interval unit. The second voltage transmission unit is connected between a first power supply and a first end of the driving module, and is used for transmitting a voltage of the first power supply to the first end of the driving module in a compensation stage. A first end of the coupling module is connected with a control end of the driving module. The voltage interval unit is connected between a second end of the driving module and a second end of the coupling module, and is used for being turned on in the compensation stage, so that the first power supply charges the coupling module, and a threshold voltage of the driving module is written to the second end of the coupling module. Through the charging compensation mode, the dispersion of the threshold voltage of the driving module is compensated, the compensation of the positive or negative bias of the threshold voltage is realized, the display uniformity is improved, and the display effect is improved.

Description

TECHNICAL FIELD

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

[0002] An organic light emitting diode display panel is driven by current to emit light, and thus the characteristics of a driving device will affect the display gray scale brightness. When the characteristics of driving devices corresponding to different pixels differ too much, the phenomenon of uneven picture quality is likely to occur. SUMMARY

[0003] The present application provides a pixel circuit, a driving method thereof and a display panel to compensate for the threshold voltage of a driving module and improve display uniformity.

[0004] According to an aspect of the present application, a pixel circuit is provided, comprising a light emitting module, a driving module, a coupling module, a second voltage transmission unit and a voltage interval unit.

[0005] A first end of the second voltage transmission unit is connected with a first power supply, a second end of the second voltage transmission unit is connected with a first end of the driving module, and the second voltage transmission unit is configured to transmit the voltage of the first power supply to the first end of the driving module in a compensation stage.

[0006] A first end of the coupling module is connected with a control end of the driving module.

[0007] A first end of the voltage interval unit is connected with a second end of the driving module, a second end of the voltage interval unit is connected with a second end of the coupling module, and the voltage interval unit is configured to be turned on in the compensation stage to enable the first power supply to charge the coupling module and write the threshold voltage of the driving module into the second end of the coupling module.

[0008] Optionally, the pixel circuit further comprises a light emitting control module and a voltage writing module.

[0009] The light emitting module, the driving module and the light emitting control module are connected in series between a first power supply and a second power supply, and the voltage of the first power supply is greater than the voltage of the second power supply.

[0010] The voltage writing module is connected with the control end of the driving module, and is configured to write a first voltage into the control end of the driving module in response to a first scanning signal in the compensation stage.

[0011] Optionally, the control end of the second voltage transmission unit and the control end of the voltage interval unit are both connected with the first scanning signal.

[0012] Optionally, the voltage writing module is further configured to write a data voltage to the second end of the coupling module in response to a second scan signal in a data writing stage.

[0013] The coupling module is configured to couple the data voltage to the control end of the driving module in the data writing stage.

[0014] Optionally, the voltage writing module is further configured to write a second voltage to the control end of the driving module in response to the first scan signal in a reset stage, and write the second voltage to the second end of the coupling module in response to the second scan signal; wherein the reset stage is located before the compensation stage.

[0015] The second voltage is less than the first voltage.

[0016] Optionally, the voltage writing module comprises a first voltage transmission unit and a data writing unit.

[0017] The first voltage transmission unit is connected to the control end of the driving module, and is configured to write the first voltage to the control end of the driving module in response to the first scan signal in the compensation stage, and write the second voltage to the control end of the driving module in response to the first scan signal in the reset stage.

[0018] The data writing unit is connected to the second end of the coupling module, and is configured to write the data voltage to the second end of the coupling module in response to the second scan signal in the data writing stage, and write the second voltage to the second end of the coupling module in response to the second scan signal in the reset stage.

[0019] Optionally, the first voltage transmission unit and the data writing unit are both connected to a data line.

[0020] The data line is configured to transmit the second voltage in the reset stage, transmit the first voltage in the compensation stage, and transmit the data voltage in the data writing stage.

[0021] Optionally, the first voltage transmission unit comprises a first transistor, and the data writing unit comprises a second transistor.

[0022] The first electrode of the first transistor is connected to the data line, the second electrode of the first transistor is connected to the control end of the driving module, and the gate of the first transistor is connected to the first scan signal.

[0023] The first electrode of the second transistor is connected to the data line, the second electrode of the second transistor is connected to the second end of the coupling module, and the gate of the second transistor is connected to the second scan signal.

[0024] Optionally, the first transistor and the second transistor are both N-type transistors.

[0025] Optionally, the second voltage transmission unit comprises a third transistor, and the voltage interval unit comprises a fourth transistor.

[0026] The first pole of the third transistor is connected with the first power supply, the second pole of the third transistor is connected with the first end of the driving module, and the gate of the third transistor is accessed to the first scanning signal.

[0027] The first pole of the fourth transistor is connected with the second end of the driving module, the second pole of the fourth transistor is connected with the second end of the coupling module, and the gate of the fourth transistor is accessed to the first scanning signal.

[0028] Optionally, the third transistor and the fourth transistor are both N-type transistors.

[0029] Optionally, the light emitting module, the driving module and the light emitting control module are connected in series between the first power supply and the second power supply.

[0030] The light emitting control module is configured to be turned on in response to a light emitting control signal in a light emitting stage, so that the driving module drives the light emitting module to emit light according to a driving current generated by a data voltage.

[0031] Optionally, the pixel circuit further comprises a storage module, and the storage module is connected between the first power supply and the second end of the coupling module.

[0032] Optionally, the storage module comprises a storage capacitor, the first end of the storage capacitor is connected with the first power supply, and the second end of the storage capacitor is connected with the second end of the coupling module.

[0033] Optionally, the driving module comprises a fifth transistor, the light emitting control module comprises a sixth transistor, and the coupling module comprises a coupling capacitor.

[0034] The first end of the light emitting module is connected with the first power supply, the first pole of the fifth transistor is connected with the second end of the light emitting module, the second pole of the fifth transistor is connected with the first pole of the sixth transistor, the second pole of the sixth transistor is connected with the second power supply, and the gate of the sixth transistor is accessed to the light emitting control signal.

[0035] The first end of the coupling capacitor is connected with the gate of the fifth transistor, and the second end of the coupling capacitor is connected with the second end of the voltage interval unit.

[0036] Optionally, the fifth transistor is an N-type transistor.

[0037] Optionally, the type of the transistor included in the second voltage transmission unit is the same as the type of the transistor included in the voltage interval unit, and the type of the sixth transistor is the same as the type of the transistor included in the second voltage transmission unit or the type of the transistor included in the voltage interval unit.

[0038] The active pulse of the first scan signal is located in the inactive pulse of the light-emitting control signal; wherein the active pulse of the first scan signal is a pulse for controlling the second voltage transmission unit and the voltage interval unit to be turned on, and the inactive pulse of the light-emitting control signal is a pulse for controlling the light-emitting control module to be turned off.

[0039] Preferably, the sixth transistor, the transistor included in the second voltage transmission unit, and the transistor included in the voltage interval unit are all N-type transistors.

[0040] Optionally, the type of the transistor included in the second voltage transmission unit is the same as the type of the transistor included in the voltage interval unit, and the type of the sixth transistor is different from the type of the transistor included in the second voltage transmission unit or the type of the transistor included in the voltage interval unit.

[0041] Optionally, the transistor included in the second voltage transmission unit and the transistor included in the voltage interval unit are both N-type transistors, and the sixth transistor is a P-type transistor.

[0042] The first scan signal is multiplexed as the light-emitting control signal.

[0043] According to another aspect of the present application, a driving method of a pixel circuit is provided for driving the pixel circuit of the previous aspect, and the driving method of the pixel circuit comprises:

[0044] In the compensation phase:

[0045] The second voltage transmission unit is controlled to be turned on to transmit the voltage of the first power supply to the first end of the driving module.

[0046] The voltage interval unit is controlled to be turned on to enable the first power supply to charge the coupling module and write the threshold voltage of the driving module to the second end of the coupling module.

[0047] According to another aspect of the present application, a display panel is provided, comprising the pixel circuit of the previous aspect.

[0048] The technical scheme of the embodiment of the present application, in the compensation stage, after the second voltage transmission unit and the voltage interval unit are turned on, the voltage output by the first power supply charges the coupling module through the turned-on second voltage transmission unit, the driving module and the voltage interval unit, so as to write the threshold voltage of the driving module into the coupling module, and then the threshold voltage is coupled to the control end of the driving module through the coupling module. Through the charging compensation mode, the dispersion of the threshold voltage of the driving module is compensated, the compensation of the positive or negative bias of the threshold voltage is realized, the display uniformity is improved, and the display effect is improved.

[0049] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0051] Figure 1 A structural schematic diagram of a pixel circuit provided by the embodiment of the present application is shown in the figure.

[0052] Figure 2 A structural schematic diagram of another pixel circuit provided by the embodiment of the present application is shown in the figure.

[0053] Figure 3 A structural schematic diagram of another pixel circuit provided by the embodiment of the present application is shown in the figure.

[0054] Figure 4 A driving timing diagram of a pixel circuit provided by the embodiment of the present application is shown in the figure.

[0055] Figure 5 A specific structural schematic diagram of a pixel circuit provided by the embodiment of the present application is shown in the figure.

[0056] Figure 6 A structural schematic diagram of another pixel circuit provided by the embodiment of the present application is shown in the figure.

[0057] Figure 7 A driving timing diagram of another pixel circuit provided by the embodiment of the present application is shown in the figure.

[0058] Figure 8 A flowchart of a driving method of a pixel circuit provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0059] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction 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 the other embodiments obtained by a person of ordinary skill in the art without creative effort should fall within the protection scope of the present application.

[0060] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. 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 including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0061] As the background art, the display panel is prone to uneven display. The inventor has found that the reason is that the threshold voltage of the transistor included in the driving module in the pixel circuit is prone to shift with the use of the display panel. The luminous brightness of the light emitting module is related to the driving current generated by the driving module, and the driving current I=k*(Vgs-Vth) 2 ; k is a parameter related to the structure of the light emitting device, and k is a constant value after the light emitting device is prepared, Vs is the voltage difference between the control end and the second end of the driving module, and Vth is the threshold voltage of the driving module. Therefore, when the threshold voltage of the driving module changes, the driving current generated under the same data voltage will not be the same, resulting in uneven display.

[0062] To solve the above technical problems, the present application provides a new pixel circuit to compensate the threshold voltage regardless of positive or negative shift by a charging compensation method, and improve the display uniformity.

[0063] Figure 1 A structural schematic diagram of a pixel circuit provided by the present application is shown in Figure 1 The pixel circuit includes a light emitting module 10, a driving module 11, a coupling module 15, a second voltage transmission unit 121 and a voltage interval unit 122.

[0064] The first end of the second voltage transmission unit 121 is connected with the first power supply VDD, the second end of the second voltage transmission unit 121 is connected with the first end d of the driving module 11, and the second voltage transmission unit 121 is used for transmitting the voltage of the first power supply VDD to the first end d of the driving module 11 in the compensation stage;

[0065] The first end of the coupling module 15 is connected with the control end of the driving module 11;

[0066] The first end of the voltage interval unit 122 is connected with the second end s of the driving module 11, the second end of the voltage interval unit 122 is connected with the second end n of the coupling module 15, and the voltage interval unit 122 is used for being turned on in the compensation stage, so that the first power supply VDD charges the coupling module 15, and the threshold voltage of the driving module 11 is written to the second end n of the coupling module 15.

[0067] The pixel circuit in the embodiment of the application further comprises a light-emitting control module 13, the light-emitting module 10, the driving module 11 and the light-emitting control module 13 are connected in series between the first power supply VDD and the second power supply VSS, and the light-emitting control module 13 is used for being turned off in response to the signal inputted from the control end in any stage except the light-emitting stage, such as the compensation stage, to avoid the light-emitting module 10 from emitting light by mistake.

[0068] The light-emitting module 10 comprises a light-emitting device, which can be an organic light-emitting device or an inorganic light-emitting device, and in the embodiment, the light-emitting device is exemplarily shown as an OLED device. The coupling module 15 can comprise a capacitor, which has a coupling function, and when the voltage of one end of the coupling module changes, the voltage of the other end changes by the same amount.

[0069] The second voltage transmission unit 121 is a switch unit, and after being turned on, the second voltage transmission unit 121 connects the first power supply VDD and the first end d of the driving module 11. The voltage interval unit 122 is a switch unit, and after being turned on, the voltage interval unit 122 connects the second end s of the driving module 11 and the second end n of the coupling module 15. Optionally, the second voltage transmission unit 121 is used for being turned on in response to the effective potential of the signal inputted from the control end in the compensation stage, to transmit the voltage of the first power supply VDD to the first end d of the driving module 11. The voltage interval unit 122 is used for being turned on in response to the effective potential of the signal inputted from the control end in the compensation stage, to charge the second end n of the coupling module 15 through the driving module 11 and the voltage interval unit 122 from the first end of the driving module 11, and the charging stops until the voltage difference between the two ends of the coupling module 15 is the threshold voltage of the driving module 11. The coupling module 15 is used for storing the threshold voltage of the driving module 11.

[0070] The technical scheme of the embodiment of the present application, in the compensation stage, after the second voltage transmission unit and the voltage interval unit are turned on, the voltage output by the first power supply charges the coupling module through the turned-on second voltage transmission unit, the driving module and the voltage interval unit, so as to write the threshold voltage of the driving module into the coupling module, and then the threshold voltage is coupled to the control end of the driving module through the coupling module. Through the charging compensation mode, the dispersion of the threshold voltage of the driving module is compensated, the compensation of the positive or negative bias of the threshold voltage is realized, the display uniformity is improved, and the display effect is improved.

[0071] Figure 2 Another structure schematic diagram of a pixel circuit provided by the embodiment of the present application is provided with reference to Figure 2 On the basis of the above embodiment, the pixel circuit further comprises a voltage writing module 14.

[0072] The light emitting module 10, the driving module 11 and the light emitting control module 13 are connected in series between the first power supply VDD and the second power supply VSS, and the voltage of the first power supply VDD is greater than the voltage of the second power supply VSS.

[0073] The voltage writing module 14 is connected with the control end of the driving module 11, and is used for writing the first voltage into the control end of the driving module 11 in response to the first scanning signal S1 in the compensation stage.

[0074] In addition to the driving module 11, the light emitting control module 13 and the voltage writing module 14 are both switching modules, and each of the above modules can comprise at least one switching device. Optionally, the control end of the second voltage transmission unit 121 and the control end of the voltage interval unit 122 are both connected with the first scanning signal S1.

[0075] The working process of the pixel circuit comprises a compensation stage, in the compensation stage, the voltage writing module 14 writes the first voltage into the control end of the driving module 11 in response to the first scanning signal S1, so as to turn on the driving module 11. The second voltage transmission unit 121 and the voltage interval unit 122 are both turned on in response to the potential of the first scanning signal S1, after the second voltage transmission unit 121, the voltage interval unit 122 and the driving module 11 are turned on, the voltage output by the first power supply VDD charges the coupling module 15 through the second voltage transmission unit 121, the driving module 11 and the voltage interval unit 122, so as to write the voltage related to the threshold voltage of the driving module 11 into the second end n of the coupling module 15, and then the threshold voltage of the driving module 11 is coupled to the control end of the driving module 11 through the coupling effect of the coupling module 15. In the light emitting stage, the light emitting control module 13 is turned on in response to the signal connected with the control end thereof, and the path for transmitting the driving current is formed after being turned on. The driving current I=k*(Vg-Vs-Vth) 2Vs is the voltage of the second end s of the driving module 11, the voltage of the control end of the driving module 11 is a potential related to the threshold voltage, therefore, after subtracting the threshold voltage, the size of the driving current is irrelevant to the threshold voltage, the discreteness of the threshold voltage of the driving module 11 is compensated, and the uniformity of the display of the screen body is improved.

[0076] With reference to the foregoing Figure 2 Optionally, the voltage writing module 14 is further configured to write the data voltage into the second end n of the coupling module 15 in response to the second scanning signal S2 in the data writing stage.

[0077] The coupling module 15 is configured to couple the data voltage to the control end of the driving module 11 in the data writing stage.

[0078] The voltage writing module 14 includes at least two switch modules, the control end of one switch module is connected to the first scanning signal S1, and the control end of the other switch module is connected to the second scanning signal S2, so as to transmit the first voltage and the data voltage respectively. The voltage writing module 14 includes a first output end and a second output end, the first output end is connected to the control end of the driving module 11, and the first output end is configured to output the first voltage to the control end of the driving module 11 in the compensation stage. The second output end is connected to the second end n of the coupling module 15, and the second output end is configured to output the data voltage to the second end n of the coupling module 15 in the data writing stage.

[0079] The working process of the pixel circuit includes a data writing stage, in the data writing stage, the voltage writing module 14 writes the data voltage into the second end n of the coupling module 15, and then uses the coupling effect of the coupling module 15 to couple the data voltage to the control end of the driving module 11, the driving module 11 generates the driving current according to the data voltage, and in the light emitting stage, the driving module 11 drives the light emitting module 10 to emit light according to the driving current.

[0080] With reference to the foregoing Figure 1 Optionally, the voltage writing module 14 is further configured to write the second voltage into the control end of the driving module 11 in response to the first scanning signal S1 in the reset stage, and write the second voltage into the second end of the coupling module 15 in response to the second scanning signal S2; the second voltage is less than the first voltage. In one frame, the reset stage is located before the compensation stage. That is, before the voltage writing module writes the first voltage in the compensation stage, the voltage writing module 14 is further configured to write the second voltage into the control end of the driving module 11 in response to the first scanning signal S1 in the reset stage, and write the second voltage into the second end of the coupling module 15 in response to the second scanning signal S2; the second voltage is less than the first voltage.

[0081] The first output end of the voltage writing module 14 is configured to output the second voltage and the first voltage to the control end of the driving module 11 in time sharing mode. Specifically, the first output end is configured to output the second voltage to the control end of the driving module 11 in the reset stage, so as to reset the control end of the driving module 11 and the first end of the coupling module 15, and is also configured to output the first voltage to the control end of the driving module 11 in the compensation stage, so as to control the driving module 11 to be turned on. The second output end of the voltage writing module 14 is configured to output the second voltage and the data voltage to the second end n of the coupling module 15 in time sharing mode. Specifically, the second output end is configured to output the second voltage to the second end n of the coupling module 15 in the reset stage, so as to reset the second end n of the coupling module 15, and is also configured to output the data voltage to the second end of the coupling module 15 in the data writing stage, so as to couple the data voltage to the control end of the driving module 11 through the coupling module 15.

[0082] Figure 3 Another structure schematic diagram of a pixel circuit provided by the embodiment of the present application is shown in FIG. 4. Figure 3 Optionally, the voltage writing module 14 comprises a first voltage transmission unit 141 and a data writing unit 142.

[0083] The first voltage transmission unit 141 is connected with the control end of the driving module 11, and is configured to write the first voltage to the control end of the driving module 11 in response to the first scanning signal S1 in the compensation stage, and is also configured to write the second voltage to the control end of the driving module 11 in response to the first scanning signal S1 in the reset stage.

[0084] The data writing unit 142 is connected with the second end n of the coupling module 15, and is configured to write the data voltage to the second end n of the coupling module 15 in response to the second scanning signal S2 in the data writing stage, and is also configured to write the second voltage to the second end n of the coupling module 15 in response to the second scanning signal S2 in the reset stage.

[0085] In an optional embodiment, the first end of the first voltage transmission unit 141 is connected with a first signal line, the second end is connected with the control end of the driving module 11, the control end is connected with the first scanning signal S1, and the first signal line outputs the second voltage in the reset stage and outputs the first voltage in the compensation stage. The first voltage transmission unit 141 is a switching unit, and is turned on to connect the first end and the second end. The first voltage transmission unit 141 is configured to transmit the second voltage to the control end of the driving module 11 in response to the effective potential of the first scanning signal S1 in the reset stage, and is also configured to transmit the first voltage to the control end of the driving module 11 in response to the effective potential of the first scanning signal S1 in the compensation stage. Here, the effective potential of the first scanning signal S1 is the potential for turning on the first voltage transmission unit 141.

[0086] The first end of the data writing unit 142 is connected with the second signal line, the second end is connected with the second end n of the coupling module 15, and the control end is connected with the second scan signal S2. The second signal line outputs the second voltage in the reset stage and outputs the data voltage in the data writing stage. The data writing unit 142 is a switching unit, and the first end and the second end are connected after being turned on. The data writing unit 142 is used for being turned on in response to the effective potential of the second scan signal S2 in the reset stage, and transmitting the second voltage to the second end n of the coupling module 15. The data writing unit 142 is also used for being turned on in response to the effective potential of the second scan signal S2 in the data writing stage, and transmitting the data voltage to the second end n of the coupling module 15. Wherein, the effective potential of the second scan signal S2 is the potential for controlling the data writing unit 142 to be turned on.

[0087] With reference to the foregoing Figure 2 Optionally, the first voltage transmission unit 141 and the data writing unit 142 are both connected with the data line Data.

[0088] The data line Data is used for transmitting the second voltage in the reset stage, transmitting the first voltage in the compensation stage, and transmitting the data voltage in the data writing stage.

[0089] The first signal line and the second signal line are the same signal line, that is, the data line Data. The data line Data is used for transmitting the second voltage in the reset stage, transmitting the second voltage to the control end of the driving module 11 and the first end of the coupling module 15 through the first voltage transmission unit 141, resetting the control end of the driving module 11 and the first end of the coupling module 15, transmitting the second voltage to the second end n of the coupling module 15 through the data writing unit 142, and resetting the second end n of the coupling module 15. The data line Data is used for transmitting the first voltage in the compensation stage, transmitting the first voltage to the control end of the driving module 11 through the first voltage transmission unit 141, and turning off the data writing unit 142 in response to the invalid potential of the second scan signal S2 in the compensation stage. The data line Data is used for transmitting the data voltage in the data writing stage, and transmitting the data voltage to the second end n of the coupling module 15 through the data writing unit 142. In the data writing stage, the first voltage transmission unit 141 is turned off in response to the invalid potential of the first scan signal S1. Wherein, the invalid potential of the first scan signal S1 is the potential for controlling the first voltage transmission unit 141 to be turned off, and the invalid potential of the second scan signal S2 is the potential for controlling the data writing unit 142 to be turned off.

[0090] The data line transmits the first voltage, the second voltage and the data voltage in time division, which can reduce the number of signal lines in the display area, is beneficial to simplify the layout of the circuit, and improve the transmittance and resolution of the screen.

[0091] With reference to the foregoing Figure 3Optionally, the pixel circuit further comprises a storage module 16, which is connected between the first power supply VDD and the second end n of the coupling module 15.

[0092] The light emitting module 10, the driving module 11 and the light emitting control module 13 are connected in series between the first power supply VDD and the second power supply VSS. Specifically, the first end of the light emitting module 11 is connected to the first power supply VDD, the second end of the light emitting module 11 is connected to the first end d of the driving module 11, the second end s of the driving module 11 is connected to the first end of the light emitting control module 13, the second end of the light emitting control module 13 is connected to the second power supply VSS, and the control end of the light emitting control module 13 is connected to the light emitting control signal EM.

[0093] The light emitting control module 13 is configured to be turned on in response to the light emitting control signal EM in the light emitting stage, so that the driving module 11 generates a driving current according to the data voltage to drive the light emitting module 10 to emit light.

[0094] In the embodiment, the second voltage transmission unit 121, the voltage interval unit 122 and the first voltage transmission unit 141 are all turned on in response to the same potential and turned off in response to the same potential.

[0095] Figure 4 A driving timing diagram of the pixel circuit provided by the embodiment of the present application is shown in the following table, Figure 4 which is suitable for Figure 3 The pixel circuit shown in the table is described with reference to Figure 3 and Figure 4 The working process of the pixel circuit includes:

[0096] In the reset stage t1, the first voltage transmission unit 141 is turned on in response to the high level of the first scan signal S1, and transmits the second voltage Vref_L transmitted by the data line Data to the control end of the driving module 11 and the first end of the coupling module 15. The data writing unit 142 is turned on in response to the high level of the second scan signal S2, and transmits the second voltage Vref_L to the second end n of the coupling module 15. The second voltage transmission unit 121 is turned on in response to the high level of the first scan signal S1, and transmits the voltage output by the first power supply VDD to the first end d of the driving module 11. The voltage interval unit 122 is turned on in response to the high level of the first scan signal S1, and transmits the second voltage Vref_L transmitted by the data line Data to the second end s of the driving module 11 through the voltage interval unit 122. The light emitting control module 13 is turned off in response to the low level of the light emitting control signal EM. In the reset stage t1, the control end of the driving module 11, the first end of the coupling module 15, the second end n of the coupling module 15 and the second end s of the driving module 11 are all reset to the second voltage Vref_L, and the first end d of the driving module 11 is reset to the voltage output by the first power supply VDD.

[0097] In the compensation phase t2, the data writing unit 142 is turned off in response to the low level of the second scan signal S2, the light emitting control module 13 is turned off in response to the low level of the light emitting control signal EM, and the first voltage transmission unit 141, the second voltage transmission unit 121 and the voltage interval unit 122 are turned on in response to the high level of the first scan signal S1. The turned-on first voltage transmission unit 141 transmits the first voltage Vref_H transmitted by the data line Data to the control end of the driving module 11, and the voltage difference between the control end and the second end s of the driving module 11 is greater than the threshold voltage Vth of the driving module 11, so that the driving module 11 is turned on. After the driving module 11 is turned on, the first power supply VDD charges the coupling module 15 and the storage module 16 until the voltage Vs of the second end s of the driving module 11 is Vref_H-Vth, and the driving module 11 is turned off.

[0098] In the data writing phase t3, the first voltage transmission unit 141, the second voltage transmission unit 121 and the voltage interval unit 122 are turned off in response to the low level of the first scan signal S1, the light emitting control module 13 is turned off in response to the low level of the light emitting control signal EM, and the data writing unit 142 is turned on in response to the high level of the second scan signal S2 to transmit the data voltage Vdata transmitted by the data line Data to the second end n of the coupling module 15. Under the coupling effect of the coupling module 15, the potential Vg of the control end of the driving module 11 is Vref_H+(Vdata-Vref_H+Vth)=Vdata+Vth.

[0099] In the light emitting phase t4, the first voltage transmission unit 141, the second voltage transmission unit 121 and the voltage interval unit 122 are turned off in response to the low level of the first scan signal S1. The data writing unit 142 is turned off in response to the low level of the second scan signal S2. The light emitting control module 13 is turned on in response to the high level of the light emitting control signal EM, and the driving module 11 generates a driving current according to the data voltage to drive the light emitting module 10 to emit light. Wherein, the driving current I=1 / 2*μ*Cox*W / L*(Vdata-V2) 2 ; μ is the electron mobility, Cox is the capacitance of the unit area channel, W / L is the width-length ratio, and V2 is the voltage output by the second power supply VSS. In the embodiment, the first power supply VDD and the second power supply VSS are both direct current power supplies.

[0100] As can be known from the formula of the driving current I, the size of the driving current I is irrelevant to the threshold voltage Vth of the driving module 11, the variation of the threshold voltage Vth is compensated, the positive and negative threshold voltage Vth is compensated, and the display uniformity is improved. Meanwhile, the first power supply VDD is formed by integral layer evaporation, and is an integral conductive layer in the display area, and the signal line of the first power supply VDD does not need to be additionally arranged, and only the signal line of the data line Data and the second power supply VSS is arranged in the pixel circuit, the signal line is less, which is beneficial to improving the screen transmittance and is also beneficial to high-resolution design.

[0101] On the basis of the above-mentioned embodiment, the embodiment of the present application further provides a specific structure of the pixel circuit. Figure 5 A specific structure of the pixel circuit provided by the embodiment of the present application is shown in the figure, Figure 3 and Figure 5 Optionally, the first voltage transmission unit 141 comprises a first transistor T1, and the data writing unit 142 comprises a second transistor T2.

[0102] The first electrode of the first transistor T1 is connected with the data line Data, the second electrode of the first transistor T1 is connected with the control end of the driving module 11, and the gate electrode of the first transistor T1 is connected with the first scanning signal S1.

[0103] The first electrode of the second transistor T2 is connected with the data line Data, the second electrode of the second transistor T2 is connected with the second end n of the coupling module 15, and the gate electrode of the second transistor T2 is connected with the second scanning signal S2.

[0104] The first transistor T1 and the second transistor T2 can both be N-type transistors, further being oxide transistors to reduce the size of the leakage current, or can both be P-type transistors, further being low-temperature polysilicon transistors to reduce the power consumption of the screen.

[0105] The second voltage transmission unit 121 comprises a third transistor T3, and the voltage interval unit 122 comprises a fourth transistor T4.

[0106] The first electrode of the third transistor T3 is connected with the first power supply VDD, the second electrode of the third transistor T3 is connected with the first end d of the driving module 11, and the gate electrode of the third transistor T3 is connected with the first scanning signal S1.

[0107] The first electrode of the fourth transistor T4 is connected with the second end s of the driving module 11, the second electrode of the fourth transistor T4 is connected with the second end n of the coupling module 15, and the gate electrode of the fourth transistor T4 is connected with the first scanning signal S1.

[0108] The third transistor T3 and the fourth transistor T4 can be N-type transistors, further oxide transistors to reduce the size of the leakage current, or can also be P-type transistors, further low-temperature polysilicon transistors to reduce the power consumption of the screen body.

[0109] The storage module 16 includes a storage capacitor C2, a first end of the storage capacitor C2 being connected with the first power supply VDD, and a second end of the storage capacitor C2 being connected with the second end n of the coupling module 15;

[0110] The driving module 11 includes a fifth transistor T5, the light-emitting control module 13 includes a sixth transistor T6, and the coupling module 15 includes a coupling capacitor C1;

[0111] The first end of the light-emitting module 10 is connected with the first power supply VDD, the first electrode of the fifth transistor T5 is connected with the second end of the light-emitting module 10, the second electrode of the fifth transistor T5 is connected with the first electrode of the sixth transistor T6, the gate electrode of the fifth transistor T5 is connected with the first end of the coupling module 15 and the voltage writing module 14, specifically, the first end of the coupling capacitor C1 and the second electrode of the first transistor T1, the second electrode of the sixth transistor T6 is connected with the second power supply VSS, and the gate electrode of the sixth transistor T6 is connected with the light-emitting control signal EM;

[0112] The first end of the coupling capacitor C1 is connected with the gate electrode of the fifth transistor T5, and the second end of the coupling capacitor C1 is connected with the second end of the voltage interval unit 122, specifically, the second electrode of the fourth transistor T4.

[0113] In the embodiment, the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5 and the sixth transistor T6 are all N-type transistors to reduce the size of the leakage current. In other embodiments, to reduce the power consumption of the screen body, the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4 and the sixth transistor T6 can all be PMOS transistors, which are not limited. Figure 5 The driving timing of the pixel circuit shown can refer to Figure 4 , and the working process is the same as the pixel circuit shown in Figure 3 , which is not described here.

[0114] Reference is made to Figures 3-5Optionally, the transistors included in the second voltage transmission unit 121 are of the same type as those included in the voltage spacing unit 122, that is, the third transistor T3 and the fourth transistor T4 are of the same type, and the sixth transistor T6 is of the same type as the transistors included in the second voltage transmission unit 121 or the voltage spacing unit 122. In this embodiment, the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5, and the sixth transistor T6 are all N-type transistors.

[0115] The effective pulse of the first scan signal S1 is located within the invalid pulse of the light emission control signal EM, so that the light emission control module 13 is turned off during both the reset and compensation phases, thus preventing the light emission module 10 from emitting light erroneously. Specifically, the effective pulse of the first scan signal S1 is the pulse that controls the second voltage transmission unit 121 and the voltage interval unit 122 to turn on, while the invalid pulse of the light emission control signal EM is the pulse that controls the light emission control module 13 to turn off.

[0116] In this embodiment, the first scan signal S1 is generated by a set of gate driving circuits, the second scan signal S2 is generated by a set of gate driving circuits, and the light emission control signal EM is generated by a set of gate driving circuits. In this embodiment, only three sets of gate driving circuits are required, and the structure is simple.

[0117] Figure 6 This is a schematic diagram of another pixel circuit structure provided in an embodiment of the present invention. Figure 7 This is a driving timing diagram for another pixel circuit provided in an embodiment of the present invention. Figure 7 The driving timing shown is applicable to Figure 6 The pixel circuit shown is a reference. Figure 6 and Figure 7 Optionally, the type of transistor included in the second voltage transmission unit 121 is the same as the type of transistor included in the voltage spacing unit 122, and the type of the sixth transistor T6 is different from the type of transistor included in the second voltage transmission unit 121 or the type of transistor included in the voltage spacing unit 122.

[0118] The first scan signal S1 is multiplexed into the light emission control signal EM.

[0119] In this embodiment, as exemplarily shown, the second voltage transmission unit 121 includes a P-type transistor T6, meaning that the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, and the fifth transistor T5 are all N-type transistors, and the sixth transistor T6 is a P-type transistor. Figure 6 The working process of the pixel circuit shown is similar to Figure 3The working process of the pixel circuit shown is similar, and will not be described here again. After the first scan signal S1 is multiplexed as the light-emitting control signal EM, the entire display panel only needs two sets of gate driving circuits, that is, the first scan signal S1 is generated through one set of gate driving circuits, and the second scan signal S2 is generated through one set of gate driving circuits, which is beneficial to realize a narrow frame.

[0120] The embodiment of the present application also provides a driving method of the pixel circuit, Figure 8 A flowchart of the driving method of the pixel circuit provided by the embodiment of the present application is shown in FIG. 6. Figure 1 And Figure 8 The method comprises the following steps.

[0121] S110: In the compensation stage, the second voltage transmission unit 121 is controlled to be turned on to transmit the voltage of the first power supply VDD to the first end d of the driving module 11; and the voltage interval unit 122 is controlled to be turned on to enable the first power supply VDD to charge the coupling module 15 and write the threshold voltage of the driving module 11 into the second end n of the coupling module 15.

[0122] After the second voltage transmission unit 121 and the voltage interval unit 122 are controlled to be turned on, the first power supply VDD and the second end n of the coupling module 15 are connected, and the first power supply VDD sequentially charges the coupling module 15 through the first voltage transmission unit 121, the driving module 11 and the voltage interval unit 122 to write the threshold voltage of the driving module 11 into the second end n of the coupling module 15, thereby compensating the threshold voltage of the driving module 11.

[0123] The technical scheme of the embodiment of the present application is that, in the compensation stage, the voltage output by the first power supply charges the coupling module through the turned-on second voltage transmission unit 121, the driving module and the voltage interval unit 122 to write the threshold voltage of the driving module into the second end of the coupling module. Through the charging compensation mode, the dispersion of the threshold voltage of the driving module is compensated, the compensation of the threshold voltage in positive or negative bias is realized, the display uniformity is improved, and the display effect is improved.

[0124] The embodiment of the present application also provides a display panel comprising the pixel circuit in any of the above-mentioned embodiments, and the display panel has the same beneficial effects as the pixel circuit, which will not be described here again.

[0125] It should be understood that the steps can be reordered, added or deleted using the various forms of flow shown above. For example, the steps described in the present application can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical scheme of the present application can be achieved, and the present application is not limited herein.

[0126] The above detailed description does not limit the scope of the application. Various modifications, combinations, sub-combinations and alternatives can be made to the detailed description. Any modification, equivalent replacement and improvement etc. made within the spirit and principle of the application shall be included in the scope of the application.

Claims

1. A pixel circuit, characterized in that, include: The light-emitting module, driving module, coupling module, second voltage transmission unit, and voltage interval unit; The first end of the second voltage transmission unit is connected to the first power supply, and the second end of the second voltage transmission unit is connected to the first end of the drive module. The second voltage transmission unit is used to transmit the voltage of the first power supply to the first end of the drive module during the compensation phase. The first end of the coupling module is connected to the control end of the drive module; The first end of the voltage interval unit is connected to the second end of the drive module, and the second end of the voltage interval unit is connected to the second end of the coupling module. The voltage interval unit is used to conduct during the compensation phase so that the first power supply charges the coupling module and writes the threshold voltage of the drive module into the second end of the coupling module. The pixel circuit further includes: a voltage writing module; the voltage writing module is connected to the control terminal of the driving module, and is used to write a first voltage to the control terminal of the driving module in response to a first scan signal during the compensation phase; The voltage writing module includes a first voltage transmission unit and a data writing unit; The first voltage transmission unit is connected to the control terminal of the drive module and is used to write the first voltage to the control terminal of the drive module in response to the first scan signal during the compensation phase, and also to write the second voltage to the control terminal of the drive module in response to the first scan signal during the reset phase. The data writing unit is connected to the second end of the coupling module and is used to write the data voltage to the second end of the coupling module in response to the second scan signal during the data writing phase, and is also used to write the second voltage to the second end of the coupling module in response to the second scan signal during the reset phase. Wherein, the first end of the first voltage transmission unit is connected to the first signal line, the first end of the data writing unit is connected to the second signal line, and the first signal line is multiplexed as the second signal line; The pixel circuit also includes a light-emitting control module; The light-emitting module, the driving module, and the light-emitting control module are connected in series between a first power supply and a second power supply, wherein the voltage of the first power supply is greater than the voltage of the second power supply. The first end of the light-emitting module is connected to the first power source.

2. The pixel circuit according to claim 1, characterized in that, The control terminal of the second voltage transmission unit and the control terminal of the voltage interval unit are both connected to the first scanning signal.

3. The pixel circuit according to claim 2, characterized in that, The voltage writing module is also used to write the data voltage to the second terminal of the coupling module in response to the second scan signal during the data writing phase. The coupling module is used to couple the data voltage to the control terminal of the drive module during the data writing phase.

4. The pixel circuit according to claim 3, characterized in that, The voltage writing module is further configured to, during the reset phase, write the second voltage to the control terminal of the drive module in response to the first scan signal, and write the second voltage to the second terminal of the coupling module in response to the second scan signal; wherein, the reset phase is located before the compensation phase; The second voltage is less than the first voltage.

5. The pixel circuit according to claim 1, characterized in that, Both the first voltage transmission unit and the data writing unit are connected to the data line; The data line is used to transmit the second voltage during the reset phase, to transmit the first voltage during the compensation phase, and to transmit the data voltage during the data writing phase.

6. The pixel circuit according to claim 5, characterized in that, The first voltage transmission unit includes a first transistor, and the data writing unit includes a second transistor; The first terminal of the first transistor is connected to the data line, the second terminal of the first transistor is connected to the control terminal of the driving module, and the gate of the first transistor is connected to the first scan signal. The first terminal of the second transistor is connected to the data line, the second terminal of the second transistor is connected to the second terminal of the coupling module, and the gate of the second transistor is connected to the second scan signal.

7. The pixel circuit according to claim 6, characterized in that, Both the first transistor and the second transistor are N-type transistors.

8. The pixel circuit according to claim 1, characterized in that, The second voltage transmission unit includes a third transistor, and the voltage interval unit includes a fourth transistor; The first terminal of the third transistor is connected to the first power supply, the second terminal of the third transistor is connected to the first terminal of the driving module, and the gate of the third transistor is connected to the first scan signal. The first terminal of the fourth transistor is connected to the second terminal of the driving module, the second terminal of the fourth transistor is connected to the second terminal of the coupling module, and the gate of the fourth transistor is connected to the first scan signal.

9. The pixel circuit according to claim 8, characterized in that, Both the third transistor and the fourth transistor are N-type transistors.

10. The pixel circuit according to any one of claims 2-9, characterized in that, The light-emitting module, the driving module, and the light-emitting control module are connected in series between the first power supply and the second power supply. The light-emitting control module is used to turn on in response to the light-emitting control signal during the light-emitting phase, so that the driving module drives the light-emitting module to emit light based on the driving current generated by the data voltage.

11. The pixel circuit according to claim 1, characterized in that, The pixel circuit also includes a storage module, which is connected between the first power supply and the second end of the coupling module.

12. The pixel circuit according to claim 11, characterized in that, The storage module includes a storage capacitor, a first end of which is connected to the first power supply, and a second end of which is connected to the second end of the coupling module.

13. The pixel circuit according to claim 1, characterized in that, The driving module includes a fifth transistor, the light-emitting control module includes a sixth transistor, and the coupling module includes a coupling capacitor; The first terminal of the fifth transistor is connected to the second terminal of the light-emitting module, the second terminal of the fifth transistor is connected to the first terminal of the sixth transistor, the second terminal of the sixth transistor is connected to the second power supply, and the gate of the sixth transistor is connected to the light-emitting control signal. The first end of the coupling capacitor is connected to the gate of the fifth transistor, and the second end of the coupling capacitor is connected to the second end of the voltage interval unit.

14. The pixel circuit according to claim 13, characterized in that, The fifth transistor is an N-type transistor.

15. The pixel circuit according to claim 14, characterized in that, The second voltage transmission unit includes transistors of the same type as the voltage interval unit, and the sixth transistor is of the same type as either the transistors included in the second voltage transmission unit or the transistors included in the voltage interval unit. The effective pulse of the first scanning signal is located within the invalid pulse of the light emission control signal; wherein, the effective pulse of the first scanning signal is a pulse that controls the second voltage transmission unit and the voltage interval unit to be turned on, and the invalid pulse of the light emission control signal is a pulse that controls the light emission control module to be turned off.

16. The pixel circuit according to claim 15, characterized in that, The sixth transistor, the transistors included in the second voltage transmission unit, and the transistors included in the voltage interval unit are all N-type transistors.

17. The pixel circuit according to claim 16, characterized in that, The second voltage transmission unit includes transistors of the same type as the voltage interval unit, while the sixth transistor is of a different type than either the transistors included in the second voltage transmission unit or the transistors included in the voltage interval unit.

18. The pixel circuit according to claim 17, characterized in that, The transistors included in the second voltage transmission unit and the transistors included in the voltage interval unit are both N-type transistors, and the sixth transistor is a P-type transistor.

19. The pixel circuit according to claim 15, characterized in that, The first scanning signal is multiplexed into the light emission control signal.

20. A driving method for a pixel circuit, characterized in that, A method for driving a pixel circuit according to any one of claims 1-19, the method comprising: During the compensation phase: The second voltage transmission unit is controlled to be turned on so as to transmit the voltage of the first power supply to the first terminal of the drive module; and the first voltage transmission unit is controlled to write the first voltage to the control terminal of the drive module. The voltage interval unit is controlled to be turned on so that the first power supply charges the coupling module and writes the threshold voltage of the driving module into the second terminal of the coupling module.

21. A display panel, characterized in that, Includes the pixel circuit described in any one of claims 1-19.

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