Pixel circuit, display panel, brightness compensation method and display device

Abstract

The present invention discloses a pixel circuit, a display panel, a brightness compensation method and a display device. The pixel circuit includes a driving module, a data writing module, a storage module, a light-emitting module and a logic control module. The driving module includes a vertical dual-gate transistor; the data writing module is used to write a data voltage to the first gate of the dual-gate transistor in the data writing stage, and the driving module is used to drive the light-emitting module to emit light in the light-emitting stage; the control end of the logic control module is connected to the first end of the light-emitting module, and the output end of the logic control module is connected to the second gate of the dual-gate transistor. The logic control module is used to adjust the threshold voltage of the dual-gate transistor according to the voltage of the first end of the light-emitting module in the light-emitting stage to compensate for the light-emitting brightness of the light-emitting module. The scheme has a simple structure and can realize the life compensation of the display panel using the pixel circuit without adding an external control IC. It can meet the design requirements in different scenarios and is conducive to reducing costs.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a pixel circuit, a display panel, a brightness compensation method and a display device. Background Art

[0002] Organic Light Emitting Diode (OLED) display panels have the characteristics of low power consumption, fast response speed, wide viewing angle and self-luminescence, and have become a research hotspot in the current field.

[0003] Existing display panels generally include a light emitting device and a pixel circuit, and the pixel circuit is used to drive the light emitting device to emit light to realize image display. However, existing display panels have the problem of display brightness attenuation, which seriously reduces the service life of the panel. Summary of the invention

[0004] The present invention provides a pixel circuit, a display panel, a brightness compensation method and a display device, so as to realize brightness self-compensation of a display panel, thereby compensating the service life of the display panel.

[0005] According to one aspect of the present invention, there is provided a pixel circuit, comprising: a driving module, a data writing module, a storage module, a light emitting module and a logic control module, wherein the driving module comprises a vertical dual-gate transistor;

[0006] The data writing module is used for writing a data voltage to the first gate of the dual-gate transistor in a data writing phase;

[0007] The driving module is connected between the first power line and the first end of the light emitting module, the second end of the light emitting module is connected to the second power line, and the driving module is used to drive the light emitting module to emit light in the light emitting stage;

[0008] The control end of the logic control module is connected to the first end of the light-emitting module, and the output end of the logic control module is connected to the second gate of the dual-gate transistor. The logic control module is used to adjust the threshold voltage of the dual-gate transistor according to the voltage of the first end of the light-emitting module during the light-emitting stage to compensate for the light-emitting brightness of the light-emitting module.

[0009] Optionally, the logic control module includes a first voltage divider unit and a second voltage divider unit, the control end of the first voltage divider unit is connected to the first switch control signal line, the first end of the first voltage divider unit is connected to the first voltage signal line, the second end of the first voltage divider unit is connected to the second gate of the dual-gate transistor, the first end of the second voltage divider unit is connected to the second voltage signal line, the second end of the second voltage divider unit is connected to the second end of the first voltage divider unit, and the control end of the second voltage divider unit is connected to the first end of the light-emitting module.

[0010] Optionally, the first switch control signal transmitted on the first switch control signal line, the first voltage signal transmitted on the first voltage signal line, and the second voltage signal transmitted on the second voltage signal line are all DC voltage signals;

[0011] The voltage magnitudes of the first switch control signal, the first voltage signal, and the second voltage signal are all associated with the brightness compensation coefficient of the light emitting module.

[0012] Optionally, the first voltage dividing unit includes a first transistor, the second voltage dividing unit includes a second transistor, the gate of the first transistor is connected to the first switch control signal line, the first electrode of the first transistor is connected to the first voltage signal line, the second electrode of the first transistor is connected to the second gate of the dual-gate transistor, the gate of the second transistor is connected to the first end of the light-emitting module, the first electrode of the second transistor is connected to the second voltage signal line, and the second electrode of the second transistor is connected to the second electrode of the first transistor;

[0013] Preferably, a channel width-to-length ratio of the second transistor is greater than a channel width-to-length ratio of the first transistor, and / or a voltage transmitted on the second voltage signal line is greater than a voltage transmitted on the first voltage signal line.

[0014] Optionally, the logic control module further includes a first switch unit and a second switch unit, the first switch unit is located on the connection path between the second end of the first voltage divider unit and the second gate of the dual-gate transistor, the control end of the first switch unit is connected to the second switch control signal line, the control end of the second switch unit is connected to the third switch control signal line, the first end of the second switch unit is connected to the first power line, and the second end of the second switch unit is connected to an end of the first switch unit connected to the second gate; the first switch unit is used to respond to the second switch control signal transmitted on the second switch control signal line to turn on or off, so as to control whether the logic control module compensates the light emitting brightness of the light emitting module, and the second switch unit is used to respond to the second switch control signal transmitted on the third switch control signal line to turn on when the first switch unit is turned off;

[0015] Preferably, the first switch unit includes a third transistor, the second switch unit includes a fourth transistor, the gate of the third transistor is connected to the second switch control signal line, the first electrode of the third transistor is connected to the second end of the first voltage divider unit, the second electrode of the third transistor is connected to the second gate of the dual-gate transistor, the gate of the fourth transistor is connected to the third switch control signal line, the first electrode of the fourth transistor is connected to the first power line, and the second electrode of the fourth transistor is connected to the second electrode of the third transistor.

[0016] According to another aspect of the present invention, a display panel is provided, comprising the pixel circuit provided by any embodiment of the present invention, wherein the logic control module controls the threshold voltage of the dual-gate transistor according to the voltage of the first end of the light-emitting module based on the first switch control signal, the first voltage signal and the second voltage signal connected to the logic control module;

[0017] The display panel includes pixel units arranged in an array, each pixel unit includes a plurality of sub-pixels of different colors, and the first switch control signal, the first voltage signal and the second voltage signal connected to the logic control module in the pixel circuit corresponding to the sub-pixels of different colors are all different.

[0018] Optionally, the first gate of the dual-gate transistor is a top gate, the second gate is a bottom gate, the display panel further comprises a substrate, and the first gate is located on a side of the second gate away from the substrate;

[0019] Preferably, the thickness of the second gate of the double-gate transistor in the pixel circuit corresponding to sub-pixels of different colors is different.

[0020] According to another aspect of the present invention, a brightness compensation method for a display panel is provided, which is used to perform brightness compensation on a display panel provided by any embodiment of the present invention; the brightness compensation method comprises:

[0021] Determining a brightness compensation coefficient of the display panel, and voltage magnitudes corresponding to the first switch control signal, the first voltage signal, and the second voltage signal;

[0022] Controlling the logic control module to adjust the threshold voltage of the dual-gate transistor according to the voltage of the first terminal of the light-emitting module;

[0023] Based on the brightness compensation coefficient, multiple groups of gamma parameters of the display panel are determined, and the light emitting brightness of the light emitting module is adjusted according to the corresponding gamma parameters.

[0024] Optionally, while adjusting the light luminance of the light emitting module according to the corresponding gamma parameter, the brightness compensation method further includes:

[0025] According to the brightness compensation coefficient, the voltages corresponding to the first switch control signal, the first voltage signal, and the second voltage signal are adjusted.

[0026] According to another aspect of the present invention, a display device is provided, comprising the display panel provided by any embodiment of the present invention.

[0027] The technical solution provided by the embodiment of the present invention feeds back the voltage change of the first end of the light-emitting module to the second gate of the dual-gate transistor by adding a logic control module in the pixel circuit, so as to generate a corresponding control signal according to the voltage change of the first end of the light-emitting module and act on the second gate of the dual-gate transistor, thereby adjusting the threshold voltage of the dual-gate transistor by the voltage difference between the second gate and the first electrode, and then controlling the light-emitting current, so that the light-emitting brightness of the light-emitting module changes to compensate for its own brightness attenuation. The solution has a simple structure and can realize the life compensation of the display panel using the pixel circuit without adding an external control IC, which can meet the design requirements in different scenarios and is conducive to reducing costs.

[0028] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A schematic diagram of the structure of a pixel circuit provided by an embodiment of the present invention;

[0031] Figure 2 A schematic structural diagram of another pixel circuit provided by an embodiment of the present invention;

[0032] Figure 3 A schematic structural diagram of another pixel circuit provided by an embodiment of the present invention;

[0033] Figure 4 A schematic structural diagram of another pixel circuit provided by an embodiment of the present invention;

[0034] Figure 5A schematic diagram of the structure of another pixel circuit provided by an embodiment of the present invention;

[0035] Figure 6 A driving timing waveform diagram of a pixel circuit provided by an embodiment of the present invention;

[0036] Figure 7 A schematic diagram of the structure of another pixel circuit provided by an embodiment of the present invention;

[0037] Figure 8 A flow chart of a brightness compensation method for a display panel provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] As described in the background technology, the existing display panels will have the problem of life attenuation, which is specifically manifested as display brightness attenuation. The inventors have found that the reason for the above problems is that the efficiency attenuation of the light-emitting device (such as OLED device) or the change in the characteristics of the driving transistor in the driving circuit is an important reason for the brightness attenuation. In the process of light emission of the light-emitting device, the light-emitting efficiency attenuation occurs due to the characteristics of the light-emitting device itself, accompanied by the problem of increased cross-voltage. When the cross-voltage at both ends of the light-emitting device increases, it will cause the potential of the driving transistor connected to the light-emitting device to rise, thereby causing the characteristics of the driving transistor to change, affecting the light-emitting current, and then affecting the light-emitting brightness. Among them, the larger the cross-voltage, the lower the brightness. The cross-voltage will increase with the increase of time. As the use time increases, the overall display brightness of the display panel will be greatly attenuated, which cannot meet the design requirements in some specific application scenarios.

[0041] In view of the above problems, an embodiment of the present invention provides a pixel circuit, which feeds back the voltage change at one end of the light-emitting device to the pixel circuit to change the light-emitting current, thereby achieving the effect of brightness self-compensation. Figure 1 A schematic diagram of a pixel circuit according to an embodiment of the present invention is provided. Figure 1 The pixel circuit includes a driving module 110, a data writing module 120, a storage module 160, a light emitting module 130 and a logic control module 140. The driving module 110 includes a vertical dual-gate transistor Q0; the data writing module 120 is used to write a data voltage Vdata to a first gate G of the dual-gate transistor Q0 during a data writing phase; the driving module 110 is connected between a first power line L1 and a first end of the light emitting module 130; a second end of the light emitting module 130 is connected to a second power line L2; the driving module 110 is used to drive the light emitting module 130 to emit light during a light emitting phase; a control end of the logic control module 140 is connected to a first end of the light emitting module 130; an output end of the logic control module 140 is connected to a second gate B of the dual-gate transistor Q0; and the logic control module 140 is used to adjust a threshold voltage of the dual-gate transistor Q0 according to a voltage at the first end of the light emitting module 130 during a light emitting phase to compensate for the light emitting brightness of the light emitting module 130.

[0042] Specifically, the driving transistor included in the driving module 110 is a vertical dual-gate transistor, the first gate G can be the top gate of the dual-gate transistor Q0, used to write the data voltage Vdata, and the second gate B is the bottom gate of the dual-gate transistor Q0. The threshold voltage of the dual-gate transistor Q0 is adjusted by setting the voltage difference between the second gate B and the first electrode S of the dual-gate transistor Q0, thereby changing the light-emitting current.

[0043] The working process of the pixel circuit provided in this embodiment at least includes a data writing stage and a light emitting stage. In the data writing stage, the data writing module 120 writes the data voltage Vdata to the first gate G of the dual-gate transistor Q0, and the storage module 160 stores the voltage at the first gate G. In the light emitting stage, the light emitting control module 150 is controlled to be turned on, the connection path between the first power line L1 and the second power line L2 is turned on, and the dual-gate transistor Q0 generates a light emitting current according to the voltage of its first gate G and the first pole S, driving the light emitting module 130 to emit light. As time goes by, when the light emitting brightness of the light emitting module 130 decays, the cross voltage between the first end and the second end of the light emitting module 130 increases, resulting in a voltage rise at the first end of the light emitting module 130. The logic control module 140 adjusts the potential of the second gate B of the dual-gate transistor Q0 according to the voltage of the first end of the light emitting module 130, so that the voltage difference between the second gate B of the dual-gate transistor Q0 and the first pole S changes, thereby adjusting the threshold voltage of the dual-gate transistor Q0.

[0044] by Figure 1 Taking the pixel circuit shown in the figure as an example, in the light-emitting stage, the light-emitting current can be expressed as:

[0045]

[0046] Wherein, μ is the electron mobility of the dual-gate transistor Q0, Cox is the channel capacitance per unit area of ​​the dual-gate transistor Q0, W / L is the width-to-length ratio of the dual-gate transistor Q0, and Vth is the threshold voltage of the dual-gate transistor Q0.

[0047] It can be seen from the above formula that according to the channel type of the dual-gate transistor Q0 (the threshold voltage Vth is positive or negative), the potential of the second gate B can be increased or decreased through the logic control module 140, so that the threshold voltage Vth of the dual-gate transistor Q0 is positively biased or negatively biased, thereby achieving the effect of increasing the luminous current, thereby achieving automatic compensation of the luminous brightness by controlling the luminous current after the luminous brightness decays.

[0048] The technical solution provided by the embodiment of the present invention feeds back the voltage change of the first end of the light-emitting module to the second gate of the dual-gate transistor by adding a logic control module in the pixel circuit, so as to generate a corresponding control signal according to the voltage change of the first end of the light-emitting module and act on the second gate of the dual-gate transistor, thereby adjusting the threshold voltage of the dual-gate transistor by the voltage difference between the second gate and the first electrode, and then controlling the light-emitting current, so that the light-emitting brightness of the light-emitting module changes to compensate for its own brightness attenuation. The solution has a simple structure and can realize the life compensation of the display panel using the pixel circuit without adding an external control IC, which can meet the design requirements in different scenarios and is conducive to reducing costs.

[0049] It should be noted that the pixel circuit used in the traditional display panel generally uses a thin film transistor as a driving transistor. The thin film transistor is a three-terminal device, and its threshold voltage is only related to the process. Under normal circumstances, when the light-emitting module 130 is driven to emit light, the threshold voltage of the driving transistor is a negative impact, and the influence of the threshold voltage on the light-emitting current needs to be eliminated. The driving transistor used in the embodiment of the present invention is a dual-gate transistor Q0 of a four-terminal device. The threshold voltage of the dual-gate transistor Q0 is changed by controlling the potential of the second gate, and the threshold voltage of the driving transistor is creatively used to compensate for the light-emitting brightness of the light-emitting module 130, thereby achieving the effect of life compensation.

[0050] Figure 2 A schematic diagram of another pixel circuit provided by an embodiment of the present invention, referring to Figure 2 The pixel circuit may further include a compensation module 170, which is connected between the first gate G and the second electrode D of the dual-gate transistor Q0. The data writing module 120 is connected to the first electrode S of the dual-gate transistor Q0. The compensation module 170 is used to compensate for the threshold voltage of the dual-gate transistor T0 during the data writing stage to improve the uniformity of the light-emitting current.

[0051] Optionally, the pixel circuit further includes a first initialization module 180 and a second initialization module 190. The first initialization module 180 is connected to the first gate G of the dual-gate transistor Q0, and is used to transmit the initialization voltage Vref to the first gate G of the dual-gate transistor Q0, and initialize the potential of the first gate G to eliminate the influence of the residual charge of the previous frame. The second initialization module 190 is connected to the first end of the light-emitting module 130, and is used to transmit the initialization voltage Vref to the first end of the light-emitting module 130 before the light-emitting stage, and initialize the potential of the first end of the light-emitting module 130. The first initialization module 180 and the second initialization module 190 may be turned on at the same time or at different times, and the voltages transmitted by the two may be the same or different.

[0052] In this embodiment, since the logic control module 140 operates after the threshold compensation of the compensation module 170, when the logic control module 140 controls the potential of the second gate B of the dual-gate transistor Q0 to change its threshold voltage, the light-emitting current can usually be changed (the expression of the light-emitting current is the same as Figure 1 The formula of the light-emitting current of the pixel current shown is the same), realizing brightness self-compensation.

[0053] Figure 3 A schematic diagram of another pixel circuit provided by an embodiment of the present invention, referring to Figure 3On the basis of the above technical solutions, optionally, the logic control module 140 includes a first voltage dividing unit 141 and a second voltage dividing unit 142, the control end of the first voltage dividing unit 141 is connected to the first switch control signal line, the first end of the first voltage dividing unit 141 is connected to the first voltage signal line U1, the second end of the first voltage dividing unit 141 is connected to the second gate B of the dual-gate transistor Q0, the first end of the second voltage dividing unit 142 is connected to the second voltage signal line U2, the second end of the second voltage dividing unit 142 is connected to the second end of the first voltage dividing unit 141, and the control end of the second voltage dividing unit 142 is connected to the first end of the light-emitting module 130.

[0054] The first voltage signal line U1 is used to transmit the first voltage signal V1, the second voltage signal line U2 is used to transmit the second voltage signal V2, and the first switch control signal line is used to transmit the first switch control signal SW1. The first voltage signal V1 can be a low level signal, and the second voltage signal V2 can be a high level signal. In the light-emitting stage, the first voltage dividing unit 141 is in a conducting state under the control of the first switch control signal SW1.

[0055] When the voltage at the first end of the light emitting module 130 increases, the second voltage divider unit 142 changes the impedance in the connection path between the first voltage signal line U1 and the second voltage signal line U2, thereby changing the node potential at the second end of the first voltage divider unit 141, that is, changing the potential of the second gate B.

[0056] As an optional implementation provided by the embodiment of the present invention, the first voltage dividing unit 141 and the second voltage dividing unit 142 may include transistors. Figure 4 A schematic diagram of another pixel circuit provided by an embodiment of the present invention, referring to Figure 4 On the basis of the above technical solution, optionally, the first voltage dividing unit 141 includes a first transistor Q1, the second voltage dividing unit 142 includes a second transistor Q2, the gate of the first transistor Q1 is connected to the first switch control signal line, the first electrode of the first transistor Q1 is connected to the first voltage signal line U1, the second electrode of the first transistor Q1 is connected to the second gate B of the dual-gate transistor Q0, the gate of the second transistor Q2 is connected to the first end of the light emitting module 130, the first electrode of the second transistor Q2 is connected to the second voltage signal line U2, and the second electrode of the second transistor Q2 is connected to the second electrode of the first transistor Q1.

[0057] Specifically, when the voltage at the first terminal of the light-emitting module 130 is raised, the conduction degree of the second transistor Q2 is reduced, and the internal resistance of the second transistor Q2 becomes larger, so that the control ability of the second transistor Q2 on the potential of the node N1 (the node connecting the first transistor Q1 and the second transistor Q2) is weakened, thereby reducing the voltage at the node N1. Under the control of the node voltage, the second gate B of the dual-gate transistor Q0 increases the threshold voltage of the dual-gate transistor Q0, and the light-emitting current becomes:

[0058]

[0059] Thereby, the light-emitting current is increased, and the light-emitting brightness of the light-emitting module 130 is further improved. When the brightness of the light-emitting module 130 decays, automatic brightness compensation is achieved, which is beneficial to improving the overall life of the panel.

[0060] In an actual pixel circuit, the channel width-to-length ratio of the second transistor Q2 is greater than the channel width-to-length ratio of the first transistor Q1, so that the switching speed of the second transistor Q2 is greater than the switching speed of the first transistor Q1, and / or the voltage transmitted on the second voltage signal line U2 is greater than the voltage transmitted on the first voltage signal line U1. In other words, the driving capability of the second voltage signal V2 transmitted on the second voltage signal line U2 can be greater than the driving capability of the first voltage signal V1 transmitted on the first voltage signal line U1, so that the potential at the node N1 is dominated by the second transistor Q2 and the second voltage signal V2.

[0061] In this embodiment, the first switch control signal SW1 transmitted on the first switch control signal line, the first voltage signal V1 transmitted on the first voltage signal line U1, and the second voltage signal V2 transmitted on the second voltage signal line U2 are all DC voltage signals; the voltage magnitudes corresponding to the first switch control signal SW1, the first voltage signal V1, and the second voltage signal V2 are all associated with the brightness compensation coefficient of the light emitting module 130. In other words, the threshold voltages of the dual-gate transistor Q0 corresponding to different brightness compensation coefficients are different, and the threshold voltage of the dual-gate transistor Q0 is controlled by the potential of the node N1, and the potential of the node N1 is associated with the voltage magnitudes of the first switch control signal SW1, the first voltage signal V1, and the second voltage signal V2. Therefore, by determining the brightness compensation coefficient and the voltage magnitudes of the first switch control signal SW1, the first voltage signal V1, and the second voltage signal V2, automatic compensation of the light emitting brightness can be achieved. At the same time, the current on the connection path between the first voltage signal line U1 and the second voltage signal line U2 can be reduced by adjusting the size of the first transistor Q1 and the second transistor Q2, and the voltage values ​​of the first voltage signal V1 and the second voltage signal V2, thereby reducing power consumption and preventing the screen power consumption from being raised too much.

[0062] Here, the brightness compensation coefficient refers to the ratio of the compensated brightness to the standard brightness (or target brightness) after the luminous brightness is attenuated. For example, if the brightness is attenuated by 10% based on the standard brightness, if the brightness compensation coefficient is 10%, it is fully compensated; if the brightness compensation coefficient is 5%, it compensates half of the attenuated brightness.

[0063] Figure 5 A schematic diagram of another pixel circuit structure provided by an embodiment of the present invention, specifically: Figure 4 The pixel circuit shown is a schematic diagram of the device structure, refer to Figure 5 The data writing module 120 includes a fifth transistor Q5, the compensation module 170 includes a sixth transistor Q6, the light emitting control module 150 includes a first light emitting control unit 1501 and a second light emitting control unit 1502, the first light emitting control unit 1501 includes a seventh transistor Q7, the second light emitting control unit 1502 includes an eighth transistor Q8, the first initialization module 180 includes a ninth transistor Q9, the second initialization module 190 includes a tenth transistor Q10, the light emitting module 130 includes a light emitting diode D1, and the storage module 160 includes a first capacitor C1.

[0064] Among them, the gates of the seventh transistor Q7 and the eighth transistor Q8 are both connected to the light-emitting control signal line, the light-emitting control signal line is used to transmit the light-emitting control signal EM, the first electrode of the seventh transistor Q7 is connected to the first power line L1, the second electrode of the seventh transistor Q7 is connected to the first electrode S of the dual-gate transistor Q0, the first electrode of the eighth transistor Q8 is connected to the second electrode D of the dual-gate transistor Q0, the second electrode of the eighth transistor Q8 is connected to the anode of the light-emitting diode D1, and the cathode of the light-emitting diode D1 is connected to the second power line L2.

[0065] The first electrode of the fifth transistor Q5 is connected to the data line to receive the data voltage Vdata transmitted by the data line, the second electrode of the fifth transistor Q5 is connected to the first electrode S of the dual-gate transistor Q0, and the gate of the fifth transistor Q5 is connected to the first scan signal line, and the first scan signal line is used to transmit the first scan signal S1. The gate of the sixth transistor Q6 is connected to the first scan signal line, the first electrode of the sixth transistor is connected to the second electrode D of the dual-gate transistor Q0, and the second electrode of the sixth transistor Q6 is connected to the first gate G of the dual-gate transistor Q0. The first electrode of the ninth transistor Q9 is connected to the initialization signal line, the second electrode of the ninth transistor Q9 is connected to the first gate G of the dual-gate transistor Q0, and the gate of the ninth transistor Q9 is connected to the second scan signal line, and the second scan signal line is used to transmit the second scan signal S2. The first electrode of the tenth transistor Q10 is connected to the initialization signal line, the second electrode of the tenth transistor Q10 is connected to the anode of the light emitting diode D1, and the gate of the tenth transistor Q10 is connected to the third scan signal line, and the third scan signal line is used to transmit the third scan signal S3.

[0066] Figure 6 A driving timing waveform diagram of a pixel circuit provided by an embodiment of the present invention can be used to drive Figure 5 The pixel circuit shown in FIG. Figure 5 and Figure 6 , taking the case where all transistors are P-type tubes as an example, the working process of the pixel circuit includes a first initialization stage T1, a data writing stage T2, a second initialization stage T3 and a light emitting stage T4.

[0067] In the first initialization stage T1, the light-emitting control signal EM is at a high level, the first scanning signal S1 is at a high level, the second scanning signal S2 is at a low level, and the third scanning signal S3 is at a high level. Therefore, the ninth transistor Q9 is turned on and the initialization voltage Vref is transmitted to the first gate G of the dual-gate transistor Q0 to initialize the potential of the first gate G.

[0068] In the data writing stage T2, the light emitting control signal EM is at a high level, the first scanning signal S1 is at a low level, the second scanning signal S2 is at a high level, and the third scanning signal S3 is at a high level, so the fifth transistor Q5 and the sixth transistor Q6 are turned on, and the data voltage Vdata is written to the first gate G via the fifth transistor Q5, the dual-gate transistor Q0 and the sixth transistor Q6, and the first capacitor C1 stores the voltage of the first gate G, thereby realizing data writing and threshold compensation of the dual-gate transistor Q0. Among them, since the potential of the second gate B of the dual-gate transistor Q0 does not change, the threshold voltage of the dual-gate transistor Q0 is fixed.

[0069] In the second initialization stage T3, the light control signal EM is at a high level, the first scanning signal S1 is at a high level, the second scanning signal S2 is at a high level, and the third scanning signal S3 is at a low level. Therefore, the tenth transistor Q10 is turned on and the initialization voltage Vref is transmitted to the anode of the light-emitting diode D1 to initialize the anode potential.

[0070] Before the light emitting stage, the second transistor Q2 remains turned off, and the potential of the second gate B of the dual-gate transistor Q0 is controlled by the first transistor Q1. Here, the first transistor Q1 can remain turned on to transmit the first voltage signal V1 to the node N1.

[0071] In the light-emitting stage T4, the light-emitting control signal EM is at a low level, the first scanning signal S1 is at a high level, the second scanning signal S2 is at a high level, and the third scanning signal S3 is at a high level. Therefore, the seventh transistor Q7 and the eighth transistor Q8 are turned on, and the dual-gate transistor Q0 generates a light-emitting current under the action of the first power supply voltage VDD, the second power supply voltage VSS and the voltage of its first gate G, driving the light-emitting diode D1 to emit light.

[0072] As time goes by, when the luminous brightness decays and the voltage across the two ends of the light-emitting diode D1 increases, as the anode voltage of the light-emitting diode D1 gradually increases, the conduction degree of the second transistor Q2 gradually changes, thereby controlling the potential change of the node N1, and then changing the voltage of the second gate B of the dual-gate transistor Q0, adjusting the threshold voltage of the dual-gate transistor Q0, controlling the light-emitting current to increase, and then compensating for the luminous brightness, and finally achieving the effect of compensating for the panel life.

[0073] Optionally, the panel includes a plurality of pixel units, and each pixel unit includes a plurality of sub-pixels, such as red, green, and blue sub-pixels. Since the brightness attenuation rate of the light-emitting diode D1 corresponding to each sub-pixel is different, the brightness compensation coefficients of different sub-pixels at the same time are different. Therefore, the first voltage signal V1, the second voltage signal V2, and the first switch control signal SW1 can be set separately for different sub-pixels to perform brightness compensation with different coefficients respectively.

[0074] Furthermore, on the basis of controlling the light-emitting current by adjusting the voltage of the second gate B of the dual-gate transistor Q0 through the voltage adjustment range of the node N1, the light-emitting current can also be adjusted simultaneously in combination with the thickness of the second gate B of the dual-gate transistor Q0 to achieve a larger brightness compensation range. The thickness of the second gate B refers to the thickness between the second gate B and the active layer. The thickness of the second gate B is different, and the control ability of the threshold voltage by the same voltage is also different. Therefore, for sub-pixels of different colors, the thickness of the second gate B of the dual-gate transistor Q0 corresponding to the sub-pixel can be set to be different.

[0075] Optionally, in another optional implementation manner provided by the present invention, the brightness compensation function may be set as an optional function. Figure 7 A schematic diagram of another pixel circuit provided by an embodiment of the present invention, referring to Figure 7On the basis of the above technical solutions, optionally, the logic control module 140 further includes a first switch unit 143 and a second switch unit 144, the first switch unit 143 is located on the connection path between the second end of the first voltage divider unit 141 and the second gate B of the dual-gate transistor Q0, the control end of the first switch unit 143 is connected to the second switch control signal line, the second switch control signal line is used to transmit the second switch control signal SW2, the first end of the first switch unit 143 is connected to the second end of the first voltage divider unit 141, the second end of the first switch unit 143 is connected to the second gate B of the dual-gate transistor Q0, and the control end of the second switch unit 144 is connected to the second end of the first voltage divider unit 141. The second switch unit 144 is connected to the third switch control signal line, which is used to transmit the third switch control signal SW3. The first end of the second switch unit 144 is connected to the first power line L1, and the second end of the second switch unit 144 is connected to the second end of the first switch unit 143. The first switch unit 143 is used to respond to the second switch control signal SW2 transmitted on the second switch control signal line to turn on or off, so as to control whether the logic control module 140 compensates for the luminous brightness of the light-emitting module 130. The second switch unit 144 is used to respond to the second switch control signal SW3 transmitted on the third switch control signal line to turn on when the first switch unit 143 is turned off.

[0076] Specifically, the first switch unit 143 includes a third transistor Q3, the second switch unit 144 includes a fourth transistor Q4, the gate of the third transistor Q3 is connected to the second switch control signal line, the first electrode of the third transistor Q3 is connected to the second end of the first voltage divider unit 141, the second electrode of the third transistor Q3 is connected to the second gate B of the dual-gate transistor Q0, the gate of the fourth transistor Q4 is connected to the third switch control signal line, the first electrode of the fourth transistor Q4 is connected to the first power line L1, and the second electrode of the fourth transistor Q4 is connected to the second electrode of the third transistor Q3.

[0077] When the third transistor Q3 is turned on in response to the second switch control signal SW2, the fourth transistor Q4 is turned off in response to the third switch control signal SW3, and the logic control module 140 controls the potential of the second gate B of the dual-gate transistor Q0 through the potential of the node N1, thereby adjusting the threshold voltage of the dual-gate transistor Q0. When the third transistor Q3 is turned off in response to the second switch control signal SW2, the node N1 no longer controls the potential of the second gate B of the dual-gate transistor Q0, and at the same time, the fourth transistor Q4 is turned on in response to the third switch control signal SW3, and the second gate B is controlled by a fixed voltage, and the threshold voltage of the dual-gate transistor Q0 is not adjusted. Therefore, this solution can realize the selection of the brightness compensation function and improve the flexibility of brightness compensation.

[0078] Optionally, an embodiment of the present invention further provides a display panel, including the pixel circuit provided by any embodiment of the present invention, wherein the display panel includes a substrate, and the pixel circuit is formed on the substrate. The display panel also has the beneficial effects described in any of the above embodiments. The display panel can be a laptop computer, or it can be a panel of any electronic product with a display function, including but not limited to the following categories: mobile phones, televisions, desktop displays, tablet computers, digital cameras, smart bracelets, smart glasses, car displays, medical equipment, industrial control equipment, touch interactive terminals, etc., and the embodiments of the present invention do not specifically limit this.

[0079] Optionally, the present invention further provides a brightness compensation method for a display panel, which is used to perform brightness compensation on the display panel provided by the above embodiment. Figure 8 A flowchart of a brightness compensation method for a display panel provided by an embodiment of the present invention, referring to Figure 8 , the brightness compensation method comprises:

[0080] S110, determining a brightness compensation coefficient of the display panel, and voltage magnitudes corresponding to the first switch control signal, the first voltage signal, and the second voltage signal.

[0081] S120, the control logic control module adjusts the threshold voltage of the dual-gate transistor according to the voltage of the first terminal of the light-emitting module.

[0082] S130 , determining a plurality of groups of gamma parameters of the display panel based on the brightness compensation coefficient, and adjusting the light emitting brightness of the light emitting module according to the corresponding gamma parameters.

[0083] Specifically, combined Figure 1 , first determine the brightness compensation coefficient required by the display panel, and the corresponding relationship between the first switch control signal SW1, the first voltage signal V1 and the second voltage signal V2, set the first switch control signal SW1, the first voltage signal V1 and the second voltage signal V2 at preset voltage values ​​respectively, and fix the voltage of the second gate B of the dual-gate transistor Q0. After the light emitting brightness of the light emitting module 130 is attenuated, the voltage at the first end of the light emitting module 130 increases, and the logic control module 140 adjusts the voltage of the second gate B of the dual-gate transistor Q0 according to the voltage at the first end of the light emitting module 130, thereby changing the threshold voltage of the dual-gate transistor Q0. For example, the voltage at the first end of the light emitting module 130 is raised by 0.1V. At this time, the threshold voltage of the dual-gate transistor Q0 is adjusted to a certain value through the logic control module 140, the light emitting current becomes larger, and the light emitting brightness increases.

[0084] However, in the process of adjusting the luminous current, the current increase amplitude is inconsistent for different gray scales, and the current increases more at high gray scales and less at low gray scales, resulting in the recovery of the luminous brightness not meeting the gamma requirement.

[0085] In this embodiment, based on the brightness compensation coefficient, multiple groups of gamma parameters of the display panel are determined, and each brightness compensation coefficient corresponds to a group of gamma parameters. Exemplarily, the brightness compensation coefficient is 20%. In the process of adjusting the luminous brightness recovery through the logic control module 140, when the brightness compensation coefficient reaches 5%, the data voltage Vdata is adjusted based on the first group of gamma parameters, thereby adjusting the luminous current; when the brightness compensation coefficient reaches 10%, the data voltage Vdata is adjusted based on the second group of gamma parameters, thereby adjusting the luminous current; when the brightness compensation coefficient reaches 15%, the data voltage Vdata is adjusted based on the third group of gamma parameters, thereby adjusting the luminous current; when the brightness compensation coefficient reaches 20%, the data voltage Vdata is adjusted based on the fourth group of gamma parameters, thereby adjusting the luminous current. By updating a certain gamma in different time periods, the problem of incompatibility between high and low grayscales in the brightness compensation process can be improved, so that brightness compensation can be better achieved.

[0086] Optionally, while adjusting the light luminance of the light emitting module 130 according to the corresponding gamma parameter, the brightness compensation method further includes:

[0087] According to the brightness compensation coefficient, the voltages corresponding to the first switch control signal SW1, the first voltage signal V1, and the second voltage signal V2 are adjusted. That is, at a certain time point, the first switch control signal SW1, the first voltage signal V1, and the second voltage signal V2 are updated synchronously with gamma, so that gamma correction and current raising are easier and more accurate, which is conducive to improving the brightness compensation accuracy.

[0088] Optionally, the present invention further provides a display device, which includes the display panel provided by any of the above embodiments. Therefore, the display device also has the beneficial effects described in any of the above embodiments, which will not be described in detail.

[0089] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0090] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pixel circuit, characterized in that: include: A driving module, a data writing module, a storage module, a light emitting module and a logic control module, wherein the driving module includes a vertical dual-gate transistor; The data writing module is used for writing a data voltage to the first gate of the dual-gate transistor in a data writing phase; The driving module is connected between the first power line and the first end of the light emitting module, the second end of the light emitting module is connected to the second power line, and the driving module is used to drive the light emitting module to emit light in the light emitting stage; The control end of the logic control module is connected to the first end of the light emitting module, and the output end of the logic control module is connected to the second gate of the dual-gate transistor. The logic control module is used to adjust the threshold voltage of the dual-gate transistor according to the voltage of the first end of the light emitting module in the light emitting stage to compensate for the light emitting brightness of the light emitting module; The logic control module includes a first voltage divider unit and a second voltage divider unit, the control end of the first voltage divider unit is connected to the first switch control signal line, the first end of the first voltage divider unit is connected to the first voltage signal line, the second end of the first voltage divider unit is connected to the second gate of the dual-gate transistor, the first end of the second voltage divider unit is connected to the second voltage signal line, the second end of the second voltage divider unit is connected to the second end of the first voltage divider unit, and the control end of the second voltage divider unit is connected to the first end of the light-emitting module.

2. The pixel circuit according to claim 1, characterized in that: The first switch control signal transmitted on the first switch control signal line, the first voltage signal transmitted on the first voltage signal line, and the second voltage signal transmitted on the second voltage signal line are all DC voltage signals; The voltage magnitudes of the first switch control signal, the first voltage signal, and the second voltage signal are all associated with the brightness compensation coefficient of the light emitting module.

3. The pixel circuit according to claim 1, characterized in that: The first voltage dividing unit includes a first transistor, and the second voltage dividing unit includes a second transistor. The gate of the first transistor is connected to the first switch control signal line, the first electrode of the first transistor is connected to the first voltage signal line, the second electrode of the first transistor is connected to the second gate of the dual-gate transistor, the gate of the second transistor is connected to the first end of the light-emitting module, the first electrode of the second transistor is connected to the second voltage signal line, and the second electrode of the second transistor is connected to the second electrode of the first transistor.

4. The pixel circuit according to claim 3, characterized in that: The channel width-to-length ratio of the second transistor is greater than the channel width-to-length ratio of the first transistor, and / or the voltage transmitted on the second voltage signal line is greater than the voltage transmitted on the first voltage signal line.

5. The pixel circuit according to claim 1, characterized in that: The logic control module also includes a first switch unit and a second switch unit, the first switch unit is located on the connection path between the second end of the first voltage divider unit and the second gate of the dual-gate transistor, the control end of the first switch unit is connected to the second switch control signal line, the control end of the second switch unit is connected to the third switch control signal line, the first end of the second switch unit is connected to the first power line, and the second end of the second switch unit is connected to an end of the first switch unit connected to the second gate; the first switch unit is used to respond to the second switch control signal transmitted on the second switch control signal line to turn on or off, so as to control whether the logic control module compensates for the luminous brightness of the light-emitting module, and the second switch unit is used to respond to the second switch control signal transmitted on the third switch control signal line to turn on when the first switch unit is turned off.

6. The pixel circuit according to claim 5, characterized in that: The first switch unit includes a third transistor, and the second switch unit includes a fourth transistor, a gate of the third transistor is connected to the second switch control signal line, a first electrode of the third transistor is connected to the second end of the first voltage divider unit, a second electrode of the third transistor is connected to the second gate of the dual-gate transistor, a gate of the fourth transistor is connected to the third switch control signal line, a first electrode of the fourth transistor is connected to the first power line, and a second electrode of the fourth transistor is connected to the second electrode of the third transistor.

7. A display panel, characterized in that: Comprising the pixel circuit according to any one of claims 1 to 6; wherein the logic control module controls the threshold voltage of the dual-gate transistor according to the voltage of the first end of the light-emitting module based on the first switch control signal, the first voltage signal and the second voltage signal connected to the logic control module; The display panel includes pixel units arranged in an array, each pixel unit includes a plurality of sub-pixels of different colors, and the first switch control signal, the first voltage signal and the second voltage signal connected to the logic control module in the pixel circuit corresponding to the sub-pixels of different colors are all different.

8. The display panel according to claim 7, characterized in that: The first gate of the dual-gate transistor is a top gate, the second gate is a bottom gate, the display panel further comprises a substrate, and the first gate is located on a side of the second gate away from the substrate.

9. The pixel circuit according to claim 8, characterized in that: The thickness of the second gate of the double-gate transistor in the pixel circuit corresponding to sub-pixels of different colors is different.

10. A brightness compensation method for a display panel, characterized in that: Used to perform brightness compensation on the display panel according to any one of claims 7 to 9; The brightness compensation method comprises: Determining a brightness compensation coefficient of the display panel, and voltage magnitudes corresponding to the first switch control signal, the first voltage signal, and the second voltage signal; Controlling the logic control module to adjust the threshold voltage of the dual-gate transistor according to the voltage of the first terminal of the light-emitting module; Based on the brightness compensation coefficient, multiple groups of gamma parameters of the display panel are determined, and the light emitting brightness of the light emitting module is adjusted according to the corresponding gamma parameters.

11. The brightness compensation method of a display panel according to claim 10, characterized in that: While adjusting the light emitting brightness of the light emitting module according to the corresponding gamma parameter, the brightness compensation method further includes: According to the brightness compensation coefficient, the voltages corresponding to the first switch control signal, the first voltage signal, and the second voltage signal are adjusted.

12. A display device, characterized in that: Comprising a display panel as described in any one of claims 7 to 9.

Images