Pixel driving circuit and method, display panel, and display device

Abstract

The present invention provides a pixel driving circuit and method, a display panel, and a display device. The pixel driving circuit comprises a light-emitting element and further comprises: a first initialization module used for initializing an anode of the light-emitting element; a second initialization module comprising a first capacitor, the second initialization module being used for initializing the first capacitor; a first charging module separately connected to a preset data signal and the second initialization module, and used for writing the preset data signal into the first capacitor; a second charging module comprising a second capacitor, a first end of the second capacitor being separately connected to the first charging module and the second initialization module; and a light-emitting driving module separately connected to the first initialization module, the second initialization module, the first charging module and the second charging module, and used for driving the light-emitting element to emit light. The present invention is conducive to mitigating the problem of flickering of display pictures of OLED display products under low-frequency driving.

Description

Pixel driving circuit and driving method thereof, display panel and display device Technical Field

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

[0002] Organic light-emitting diodes (OLEDs), with their advantages of low power consumption, low cost, self-luminescence, wide viewing angles, and fast response times, have become a research hotspot in the display field. Electronic products use different refresh rates for different application scenarios. For example, a higher refresh rate is used to display dynamic images to ensure smoothness, while a lower refresh rate is used to display static images to reduce power consumption. Electronic products using organic self-luminous technology can experience flicker when displayed at low refresh rates, affecting the visual experience.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to ordinary technicians in this field.

[0004] Summary of the Invention

[0005] In view of this, the present invention provides a pixel driving circuit and a driving method thereof, a display panel and a display device to improve the problem of display screen flickering in OLED display products under low-frequency driving.

[0006] According to one aspect of the present invention, there is provided a pixel driving circuit, comprising:

[0007] Light-emitting element;

[0008] A first initialization module, configured to initialize the anode of the light-emitting element;

[0009] A second initialization module includes a first capacitor, and the second initialization module is used to initialize the first capacitor;

[0010] a first charging module, connected to the preset data signal and the second initialization module respectively, and configured to write the preset data signal into the first capacitor;

[0011] A second charging module includes a second capacitor, wherein a first end of the second capacitor is connected to the first charging module and the second initialization module respectively; and

[0012] The light-emitting driving module is respectively connected to the first initialization module, the second initialization module, the first charging module and the second charging module, and is used to drive the light-emitting element to emit light.

[0013] Optionally, the pixel driving circuit further includes:

[0014] The third initialization module is connected to the first initialization module and the light-emitting driving module respectively; the third initialization module and the light-emitting driving module are connected to form a first node, and the third initialization module is used to initialize the potential of the first node.

[0015] Optionally, the first charging module includes a third switching device and a ninth switching device, the first electrode of the third switching device is connected to the first capacitor, the first electrode of the ninth switching device is connected to the preset data signal, and the second electrode of the third switching device is connected to the second electrode of the ninth switching device.

[0016] Optionally, the light-emitting driving module includes a second switching device, and a gate of the second switching device is connected to a gate of the ninth switching device.

[0017] Optionally, the gate of the second switching device, the gate of the ninth switching device and the first capacitor are connected to form a second node; when all switching devices in the first charging module are turned on, a voltage corresponding to the preset data signal is written to the second node.

[0018] Optionally, the first charging module includes a third switching device, a first electrode of the third switching device is connected to the first capacitor, and a second electrode of the third switching device is connected to the light-emitting driving module.

[0019] Optionally, the third initialization module includes an eighth switching device, and a second electrode of the eighth switching device is connected to the light-emitting driving module to form a first node.

[0020] Optionally, the first initialization module includes a seventh switching device, a gate of the seventh switching device and a gate of the eighth switching device are connected to the same scan signal, and a second electrode of the seventh switching device is connected to the anode of the light-emitting element.

[0021] Optionally, the first charging module includes a third switching device, the second initialization module includes a sixth switching device, the third switching device and the sixth switching device are dual-gate transistors, and the second end of the second capacitor is connected between the source and the drain of the third switching device, and between the source and the drain of the sixth switching device.

[0022] According to another aspect of the present invention, a pixel driving method is provided, which is applied to any of the above-mentioned pixel driving circuits, and the method includes:

[0023] Initializing the anode of the light-emitting element using the first initialization module;

[0024] Initializing the first capacitor using the second initialization module;

[0025] Using the first charging module to write the preset data signal into the first capacitor;

[0026] implementing capacitive coupling using the second charging module; and

[0027] The light-emitting driving module is used to drive the light-emitting element to emit light.

[0028] According to another aspect of the present invention, a display panel is provided, comprising any one of the above-mentioned pixel driving circuits.

[0029] According to another aspect of the present invention, a display device is provided, comprising the above-mentioned display panel.

[0030] The beneficial effects of the present invention compared with the prior art are:

[0031] The pixel driving circuit and driving method thereof, display panel, and display device provided by the present invention provide a second capacitor C2. By utilizing the capacitive coupling effect of the second capacitor C2, the leakage amount flowing from the second node N2 toward the third switching device T3 and the leakage amount flowing toward the sixth switching device T6 are reduced, thereby weakening the potential fluctuation at the N2 point. This is beneficial to improving the low-frequency flicker problem of OLED display products and enhancing their display effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are incorporated into and constitute a part of this specification, illustrate embodiments consistent with the present invention, and together with the description, serve to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and it is clear that those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0033] FIG1 is a schematic structural diagram of a pixel driving circuit in the prior art;

[0034] FIG2 is a schematic diagram showing brightness changes of two adjacent frames of a pixel driving circuit in the prior art when the refresh rate is 60 Hz;

[0035] FIG3 is a schematic diagram showing brightness changes of two adjacent frames of a pixel driving circuit in the prior art when the refresh rate is 30 Hz;

[0036] FIG4 is a schematic structural diagram of a pixel driving circuit disclosed in an embodiment of the present invention;

[0037] FIG5 is a schematic structural diagram of a pixel driving circuit disclosed in another embodiment of the present invention;

[0038] FIG6 is a schematic diagram of the working timing corresponding to the pixel driving circuit in FIG5 ;

[0039] FIG7 is a schematic structural diagram of a pixel driving circuit disclosed in another embodiment of the present invention;

[0040] FIG8 is a schematic diagram of the working timing of the pixel driving circuit in FIG7 ;

[0041] FIG9 is a schematic structural diagram of a pixel driving circuit disclosed in another embodiment of the present invention. DETAILED DESCRIPTION

[0042] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention will be comprehensive and complete, and the concept of the example embodiments will be fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, materials, devices, etc. may be adopted. In other cases, well-known technical solutions are not shown or described in detail to avoid blurring various aspects of the present disclosure. The same reference numerals in the figures represent the same or similar structures, and their detailed descriptions will be omitted.

[0043] The terms "a," "an," "the," "said," and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including," "having," and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc.

[0044] During the driving process of the pixel driving circuit, in the light-emitting stage, the storage capacitor (refer to capacitor C1 in Figure 1) is used to maintain the voltage signal, so that the potential of its signal holding end (refer to the end of capacitor C1 close to point N2 in Figure 1) can be kept constant, forming a voltage between the gate and source of the driving transistor (refer to transistor T2 in Figure 1), controlling the driving transistor to form a driving current, and then driving the light-emitting diode to emit light.

[0045] Referring to Figure 1 , in the prior art, transistor T2, capacitor C1, and transistor T6 are connected together to form a second node N2. When the display panel is in a low refresh rate state, a leakage path exists at point N2. That is, during the light-emitting phase, the storage capacitor leaks electricity to other locations, causing the potential at the signal holding end of the storage capacitor to be unable to remain constant for a long time (i.e., the potential at point N2 changes significantly). This leads to unstable driving current generated by the driving transistor, resulting in low-frequency flicker on the display panel.

[0046] Furthermore, as the refresh rate decreases, visual flicker becomes more pronounced. Refer to Figures 2 and 3 for a comparison. Figure 2 shows the brightness change curve at a 60Hz refresh rate, while Figure 3 shows the brightness change curve at a 30Hz refresh rate. △LV represents the difference in brightness between two adjacent frames. As can be seen from Figures 2 and 3, the brightness change difference △LV1 at a 30Hz refresh rate is greater than the brightness change difference △LV2 at a 30Hz refresh rate. This means that low-frequency flicker is more pronounced.

[0047] To address the above-mentioned issues, one embodiment of the present invention discloses a pixel driving circuit. The pixel driving circuit includes a first initialization module, a second initialization module, a first charging module, a second charging module, and a light-emitting driver module. The light-emitting driver module includes a light-emitting element. The light-emitting driver module is configured to drive the light-emitting element to emit light. The first charging module is connected to the second initialization module. The second charging module is connected to the first charging module and the second initialization module, respectively. The light-emitting driver module is connected to the first initialization module, the second initialization module, the first charging module, and the second charging module, respectively.

[0048] In this embodiment, the first initialization module is used to initialize the anode of the above-mentioned light-emitting element. The second initialization module includes a first capacitor, and the above-mentioned second initialization module is used to initialize the above-mentioned first capacitor. The first charging module is connected to the preset data signal, and the first charging module is used to write the above-mentioned preset data signal into the above-mentioned first capacitor. The second charging module includes a second capacitor, and the first end of the above-mentioned second capacitor is respectively connected to the above-mentioned first charging module and the above-mentioned second initialization module. The light-emitting driving module is used to drive the above-mentioned light-emitting element to emit light. The second charging module is used to achieve capacitive coupling to reduce the voltage difference between the second node N2 and other preset nodes, thereby reducing the voltage fluctuation and leakage at the second node N2.

[0049] In this embodiment, the first initialization module is respectively connected to the fourth scanning signal S n+1 and the second reference voltage signal Vint2, the second initialization module is respectively connected to the second scanning signal S n-1 , the first reference voltage signal Vint1 and the fourth reference voltage signal ELVDD are connected, and the first charging module is connected to the preset data signal DATA and the third scan signal Sn The second charging module is connected to the fourth reference voltage signal ELVDD. The light emitting driving module is connected to the first scanning signal EM, the fourth reference voltage signal ELVDD and the fifth reference voltage signal ELVSS respectively.

[0050] 4 , in this embodiment, the first initialization module includes a seventh switching device T7, and the gate of the seventh switching device T7 is connected to the fourth scan signal S n+1 The first electrode of the seventh switch device T7 is connected to the second reference voltage signal Vint2, and the second electrode of the seventh switch device T7 is connected to the light driving module. Specifically, the second electrode of the seventh switch device T7 is connected to the anode of the light emitting element D1 in the light driving module.

[0051] The first charging module includes a first switching device T1, a second switching device T2 and a third switching device T3. The gate of the first switching device T1 and the gate of the third switching device T3 are both connected to the third scanning signal S n The first electrode of the first switching device T1 is connected to the preset data signal DATA, and the second electrode of the first switching device T1 is connected to the first electrode of the second switching device T2. The first electrode of the third switching device T3 is connected to the second initialization module. The third electrode, i.e., the gate electrode, of the second switching device T2 is connected to the second initialization module to form a second node N2.

[0052] In this embodiment, the second switching device T2 is a driving transistor. In the manufacturing process of the pixel driving circuit, the second switching device T2 can have any shape, such as an S-shape, a U-shape, an N-shape, a step-shaped shape, a straight-line shape, or a slash-shaped shape. However, to reduce optical issues caused by process fluctuations affecting the driving transistor T2, the second switching device T2 should have a maximum possible line width and line length within the space accommodating the circuit.

[0053] The second initialization module includes a first capacitor C1 and a sixth switch device T6. The first end of the first capacitor C1 is connected to the fourth reference voltage signal ELVDD, and the second end is connected to the first electrode of the sixth switch device T6. The second electrode of the sixth switch device T6 is connected to the first reference voltage signal Vint1, and the third electrode, i.e., the gate of the sixth switch device T6 is connected to the second scan signal S n-1 .

[0054] The second charging module includes a second capacitor C2. A first end of the second capacitor C2 is connected to the fourth reference voltage signal ELVDD, and a second end is connected to the sixth switching device T6 and the third switching device T3. Specifically, the second end of the second capacitor C2 is connected to the third switching device T3 to form a node N4, and is connected to the sixth switching device T6 to form a node N5.

[0055] Continuing with FIG4 , in this embodiment, the gate of the second switching device T2, the second end of the first capacitor C1, and the first electrode of the sixth switching device T6 are connected together to form a second node N2. The first electrode of the third switching device T3, the second end of the first capacitor C1, and the first electrode of the sixth switching device T6 are connected together to form a node. When both the first and third switching devices T1 and T3 are turned on, a voltage corresponding to the preset data signal DATA is written to the second node N2.

[0056] The light-emitting driver module includes a fourth switching device T4, a second switching device T2, and a fifth switching device T5, which are connected in sequence. Specifically, a first electrode of the fourth switching device T4 is connected to a fourth reference voltage signal ELVDD. A second electrode of the fourth switching device T4, a second electrode of the first switching device T1, and a first electrode of the second switching device T2 are commonly connected to form a first node N1. A second electrode of the fifth switching device T5, an anode of the light-emitting element D1, and a second electrode of the seventh switching device T7 are commonly connected to form a node. The gates of the fourth switching device T4 and the fifth switching device T5 are commonly connected to a first scan signal EM.

[0057] In this embodiment, the second electrode of the third switching device T3 is connected to the light-emitting driver module. Specifically, the second electrode of the third switching device T3, the second electrode of the second switching device T2, and the first electrode of the fifth switching device T5 are connected together to form a third node N3. However, the present invention is not limited to this. When the first switching device T1 and the third switching device T3 are both turned on, a voltage corresponding to the preset data signal DATA is written to the third node N3.

[0058] From the above structure, it can be seen that the third scanning signal S n The first scan signal EM controls the on / off of the first switching device T1 and the on / off of the third switching device T3. The first scan signal EM controls the on / off of the fourth switching device T4 and the on / off of the fifth switching device T5. The fourth scan signal S n+1 Controls the on and off of the seventh switch device T7. The second scan signal S n-1 Controlling the on and off of the sixth switching device T6.

[0059] In this embodiment, the third switching device T3 and the sixth switching device T6 are both dual-gate transistors. As shown in FIG4 , the node N4 is a point in the channel between the source and drain of the third switching device T3. The node N5 is a point in the channel between the source and drain of the sixth switching device T6.

[0060] In the same frame period, the third scanning signal S n The time when the non-effective level signal jumps to the effective level signal is later than the second scanning signal S n-1 At the moment when the non-effective level signal changes to the effective level signal, the fourth scanning signal S n+1 The time when the non-effective level signal changes to the effective level signal is later than the third scanning signal S n The moment when the non-valid level signal jumps to the valid level signal.

[0061] The pixel driving circuit disclosed in the embodiment corresponding to FIG. 4 of the present invention is provided with a second capacitor C2. On the one hand, in the third scanning signal S n When the active level signal changes to an inactive level signal, the capacitive coupling effect of the second capacitor C2 causes the potential increase degree of the node N4 in the third switch device T3 to decrease, thereby reducing the voltage difference between the node N4 and the second node N2, which is beneficial to reducing the leakage from the second node N2 to the third switch device T3, thereby weakening the potential fluctuation of the N2 point and the brightness fluctuation of the light-emitting element D1, which is beneficial to improving the low-frequency flicker problem of the OLED display product.

[0062] On the other hand, in the second scanning signal S n-1 When the active level signal changes to an inactive level signal, the capacitive coupling effect of the second capacitor C2 causes the potential of the node N5 in the third switch device T6 to increase, thereby reducing the voltage difference between the second node N2 and the node N5, which is beneficial to reducing the leakage from the second node N2 to the third switch device T6, thereby weakening the potential fluctuation of the N2 point and the brightness fluctuation of the light-emitting element D1, which is beneficial to improving the low-frequency flicker problem of the OLED display product.

[0063] In some alternative embodiments, based on the embodiment corresponding to FIG. 4 , the first reference voltage signal Vint1, the second reference voltage signal Vint2, and the fifth reference voltage signal ELVSS have the same potential polarity, while the fifth reference voltage signal ELVSS and the fourth reference voltage signal ELVDD have opposite potential polarities. The fourth reference voltage signal ELVDD is a positive potential, i.e., a positive power supply voltage output. The fifth reference voltage signal ELVSS is a negative potential, i.e., a negative power supply voltage output.

[0064] All switching devices involved in the above embodiments of the present invention can be P-type thin film transistors or N-type thin film transistors. And all switching devices in the circuit are of the same type, that is, all are P-type thin film transistors, or all are N-type thin film transistors. When all are P-type thin film transistors (i.e., P-type TFTs), the corresponding active level signal is a low level, and the inactive level signal is a high level. When all are N-type thin film transistors (N-type TFTs), the corresponding active level signal is a high level, and the inactive level signal is a low level.

[0065] It should be noted that in this embodiment, the switching devices selected in the circuit design of this embodiment are all P-type TFTs, and the corresponding effective level signal is a low level. However, the type of switching devices selected in this application is not limited to this.

[0066] It should be further noted that the first electrode of all switching devices involved in the above embodiments of the present invention can be either a source or a drain, and the second electrode can also be the other of the source and drain. That is, for example, when the first electrode is a source, the second electrode is a drain. When the first electrode is a drain, the second electrode is a source.

[0067] Another embodiment of the present invention also discloses another pixel driving circuit. As shown in FIG5 , this embodiment, based on the embodiment corresponding to FIG4 , further includes a third initialization module. The third initialization module is connected to the first initialization module and the light-emitting driving module. The third initialization module is configured to initialize the potential of the first node.

[0068] In this embodiment, the third initialization module is connected to the light-emitting driving module to form a first node. Specifically, the third initialization module includes an eighth switching device T8. The first electrode of the eighth switching device T8 is connected to the third reference voltage signal Vint3, and the second electrode of the eighth switching device T8 is connected to the light-emitting driving module to form a first node. That is, the second electrode of the eighth switching device T8, the second electrode of the fourth switching device T4, the second electrode of the first switching device T1, and the first electrode of the second switching device T2 are connected together to form the first node N1. The gate of the eighth switching device T8 and the gate of the seventh switching device T7 are connected to the same scan signal, that is, both are connected to the fourth scan signal S n+1 .

[0069] In some embodiments, the potential polarity of the third reference voltage signal Vint3 is opposite to the potential polarity of the first reference voltage signal Vint1. For example, the potential polarity of the first reference voltage signal Vint1 is a negative voltage, and the potential polarity of the third reference voltage signal Vint3 is a positive voltage.

[0070] Referring to FIG6, an embodiment of the present invention discloses a timing diagram of the operation of the pixel driving circuit corresponding to FIG5. As shown in FIG6, in the first period (i.e., period 1 in FIG6), the first scanning signal EM and the second scanning signal S are n-1 , the third scanning signal S n and the fourth scanning signal S n+1 Both are high level, the fourth switch device T4 and the fifth switch device T5 are turned off, and the light emitting element D1 does not emit light, that is, the light emitting element D1 is in the off state.

[0071] In the second period (ie, period 2 in FIG. 6 ), the second scanning signal S n-1 = is low, the sixth switch device T6 is turned on, the voltage corresponding to the first reference voltage signal Vint1 is written into the first capacitor C1, and the potential of the second node N2 is reset to the voltage corresponding to the first reference voltage signal Vint1, turning on the second transistor T2.

[0072] At the end of the second period, that is, S n-1 During the voltage jump phase, the second capacitor C2 is pulled by the voltage to which it is connected, resulting in capacitive coupling. The capacitive coupling of the second capacitor C2 causes the potential of the node N5 in the third switch device T6 to increase, thereby reducing the voltage difference between the second node N2 and the node N5, which is beneficial to reducing the leakage from the second node N2 to the third switch device T6.

[0073] In the third period (ie, period 3 in FIG6 ), the first scan signal EM is at a high level, the fourth switching device T4 and the fifth switching device T5 are turned off, and the light emitting element D1 does not emit light.

[0074] In the fourth period (ie, period 4 in FIG. 6 ), the third scan signal S n = is low level, the first switch device T1 and the third switch device T3 are turned on. The first node N1, the second node N2 and the third node N3 are all written with the voltage V corresponding to the preset data signal DATA. DATA .

[0075] At the end of the fourth period, that is, S n During the voltage jump phase, the second capacitor C2 is pulled by the voltage to which it is connected, resulting in capacitive coupling. The capacitive coupling of the second capacitor C2 causes the potential increase of the node N4 in the third switch device T3 to decrease, thereby reducing the voltage difference between the node N4 and the second node N2, which helps to reduce the leakage from the second node N2 to the third switch device T3.

[0076] In the fifth period (ie, period 5 in FIG6 ), the first scan signal EM is at a high level, the fourth switching device T4 and the fifth switching device T5 are turned off, and the light emitting element D1 does not emit light.

[0077] In the sixth period (ie, period 6 in FIG. 6 ), the fourth scan signal S n+1 When the voltage is low, the seventh and eighth switching devices T7 and T8 are turned on, and the anode of the light-emitting element D1 is reset to a voltage corresponding to the second reference voltage signal Vint2. The potentials of the first node N1 and the third node N3 are both reset to a voltage corresponding to the third reference voltage signal Vint3.

[0078] In the seventh period (ie, period 7 in FIG. 6 ), the first scan signal EM is at a high level, the fourth switching device T4 and the fifth switching device T5 are turned off, and the light emitting element D1 does not emit light.

[0079] In the eighth period (ie, period 8 in FIG. 6 ), the first scan signal EM is at a low level, the second switching device T2 , the fourth switching device T4 , and the fifth switching device T5 are all turned on, and the light emitting element D1 emits light.

[0080] In the ninth period (ie, period 9 in FIG. 6 ), the first scan signal EM is at a high level, the fourth switching device T4 and the fifth switching device T5 are turned off, and the light emitting element D1 does not emit light.

[0081] In the tenth period (ie, period 10 in FIG. 6 ), the fourth scan signal S n+1 The seventh and eighth switching devices T7 and T8 are turned on, and the anode of the light emitting element D1 is reset to a voltage corresponding to the second reference voltage signal Vint2. The potential of the first node N1 is reset to a voltage corresponding to the third reference voltage signal Vint3.

[0082] In the eleventh period (ie, period 11 in FIG. 6 ), the first scan signal EM is at a high level, the fourth switching device T4 and the fifth switching device T5 are turned off, and the light emitting element D1 does not emit light.

[0083] In the twelfth period (ie, period 12 in FIG. 6 ), the first scan signal EM is at a low level, the second switching device T2 , the fourth switching device T4 , and the fifth switching device T5 are all turned on, and the light emitting element D1 emits light.

[0084] The pixel driving circuit disclosed in the embodiment corresponding to FIG. 5 of the present invention adds an eighth switch device T8 at the first node N1, so that when the first scanning signal EM is at a high level and the fourth scanning signal S n+1When it is at a low level, the eighth switching device T8 is turned on, and the conduction path of the third reference voltage signal Vint3 is: sequentially transmitted through the eighth switching device T8, the first node N1, and the second switching device T2 to the third node N3, so that the potentials of points N1 and N3 are both reset to the voltage corresponding to the third reference voltage signal Vint3. This can, on the one hand, reduce the influence of the hysteresis effect of the second switching device T2, that is, the driving transistor, on the flicker; on the other hand, after the potential at point N3 is rewritten, the change in the potential at point N4 caused by the leakage of T3b (the third switching device T3 includes T3a and T3b) can be reduced, thereby reducing the voltage difference between the midpoint N4 of the third switching device T3 and the second node N2, and improving the potential fluctuation of point N2, thereby improving the low-frequency flicker problem of the display panel and enhancing the display effect.

[0085] Another embodiment of the present invention also discloses another pixel driving circuit. As shown in FIG7 , in addition to the embodiment corresponding to FIG4 , the first charging module further includes a ninth switching device T9, wherein the first electrode of the ninth switching device T9 is connected to the preset data signal DATA. This embodiment differs from the embodiment corresponding to FIG4 in that the second electrode of the third switching device T3 is connected to the second electrode of the ninth switching device T9, rather than to the light-emitting driving module. Furthermore, the third switching device T3 and the ninth switching device T9 are connected to form a node N3′.

[0086] In this embodiment, the gate of the second switching device T2 is connected to the gate of the ninth switching device T9, i.e., they share a common gate. Specifically, the gate of the second switching device T2, the gate of the ninth switching device T9, the second end of the first capacitor C1, and the first electrode of the sixth switching device T6 are connected together to form the second node N2. After the potential at point N2 is reset to the voltage corresponding to the first reference voltage signal Vint1, the second switching device T2 and the ninth switching device T9 are turned on. Then, after the first switching device T1 and the third switching device T3 are turned on, the voltage corresponding to the preset data signal DATA is transmitted in the following manner: via the first switching device T1, the ninth switching device T9, the node N3', the fourth node N4, and the third switching device T3, and then written to the node N2.

[0087] Referring to FIG8 , an embodiment of the present invention discloses a schematic diagram of the operating timing of the pixel driving circuit corresponding to FIG7 . As shown in FIG8 , during a first time period (i.e., time period 1 in FIG8 ), the first scanning signal EM is at a high level, the fourth switching device T4 and the fifth switching device T5 are turned off, and the light-emitting element D1 does not emit light, i.e., the light-emitting element D1 is in an off state.

[0088] In the second period (ie, period 2 in FIG. 8 ), the second scanning signal S n-1= is low, the sixth switch device T6 is turned on, the voltage corresponding to the first reference voltage signal Vint1 is written into the first capacitor C1, and the potential of the second node N2 is reset to the voltage corresponding to the first reference voltage signal Vint1, turning on the second transistor T2.

[0089] In the third period (ie, period 3 in FIG. 8 ), the third scanning signal S n = is low level, the first switch device T1 and the third switch device T3 are turned on. The node N3', the fourth node N4 and the second node N2 are all written with the voltage V corresponding to the preset data signal DATA. DATA .

[0090] In the fourth period (ie, period 4 in FIG. 8 ), the fourth scanning signal S n+1 The voltage is low, the seventh switch device T7 is turned on, and the anode of the light-emitting element D1 is reset to the voltage corresponding to the second reference voltage signal Vint2.

[0091] In the fifth period (ie, period 5 in FIG8 ), the first scan signal EM is at a high level, the fourth switching device T4 and the fifth switching device T5 are turned off, and the light emitting element D1 does not emit light.

[0092] During the sixth period (i.e., period 6 in FIG. 8 ), the first scan signal EM is at a low level, the second switching device T2, the fourth switching device T4, and the fifth switching device T5 are all turned on, and the light-emitting element D1 emits light. At this time, the voltage at the first node N1 is the voltage corresponding to the fourth reference voltage signal ELVDD.

[0093] In the embodiment corresponding to FIG. 7 of the present invention, a second capacitor C2 and a ninth switching device T9 are provided in the circuit, so that after charging, that is, after the preset data signal DATA is written into the node N3′, the fourth node N4, and the second node N2, the potential of the N4 point is equal to that of the N2 point. Then, the voltage difference between the third switching device T3 and the sixth switching device T6 is zero, thereby reducing the leakage of the N2 point, thereby improving the low-frequency flicker problem of the OLED display product.

[0094] Another embodiment of the present invention also discloses another pixel driving circuit. As shown in FIG9 , this embodiment, based on the embodiment corresponding to FIG7 , further includes a third initialization module. The third initialization module is connected to the first initialization module and the light-emitting driving module. The third initialization module is configured to initialize the potential of the first node.

[0095] In this embodiment, the third initialization module is connected to the light-emitting driving module to form a first node. Specifically, the third initialization module includes an eighth switching device T8. The first electrode of the eighth switching device T8 is connected to the third reference voltage signal Vint3, and the second electrode of the eighth switching device T8 is connected to the light-emitting driving module to form a first node. That is, the second electrode of the eighth switching device T8, the second electrode of the fourth switching device T4, the second electrode of the first switching device T1, and the first electrode of the second switching device T2 are connected together to form the first node N1. The gate of the eighth switching device T8 and the gate of the seventh switching device T7 are connected to the same scan signal, that is, both are connected to the fourth scan signal S n+1 The operation timing diagram of the pixel driving circuit in this embodiment can be referred to FIG6 .

[0096] The pixel driving circuit disclosed in the embodiment corresponding to FIG. 9 of the present invention adds an eighth switch device T8 at the first node N1, so that when the first scanning signal EM is at a high level and the fourth scanning signal S n+1 When it is at a low level, the eighth switching device T8 is turned on, and the potentials of points N1 and N3 are reset to the voltage corresponding to the third reference voltage signal Vint3. This can reduce the impact of the hysteresis effect of the second switching device T2, that is, the driving transistor, on the flicker, which is beneficial to improving the low-frequency flicker problem of the display panel and enhancing the display effect.

[0097] Another embodiment of the present invention further discloses a pixel driving method, which is applied to the pixel driving circuit disclosed in any of the above embodiments. The detailed structural features and advantages of the pixel driving circuit can be found in the description of the above embodiments and will not be repeated here. The above method includes:

[0098] S110 , utilizing a first initialization module to initialize the anode of the light emitting element.

[0099] S120: Initialize the first capacitor using a second initialization module.

[0100] S130: Utilize a first charging module to write the preset data signal into the first capacitor.

[0101] S140, using the second charging module to achieve capacitive coupling. And

[0102] S150: Using a light-emitting driving module to drive the light-emitting element to emit light.

[0103] A frame period of the circuit operation includes a reset phase, a charging phase, and a light-emitting phase. Steps S110 and S120 correspond to the reset phase, steps S130 and S140 correspond to the charging phase, and step S150 corresponds to the light-emitting phase.

[0104] An embodiment of the present invention further discloses a display panel, which includes the pixel driving circuit disclosed in any of the above embodiments. The detailed structural features and advantages of the pixel driving circuit can be found in the description of the above embodiments and will not be repeated here.

[0105] In an optional embodiment, the display panel has multiple light-emitting elements. The solution of the present application can improve the problem of uneven display caused by uneven brightness of the multiple light-emitting elements, reduce the visual flicker, and thus improve the display effect.

[0106] Some embodiments of the present disclosure further provide a display device, which includes the above-mentioned display panel.

[0107] The display device provided by the embodiments of the present disclosure can be any device that displays an image, whether in motion (e.g., video) or fixed (e.g., still image), and whether text or text. More specifically, it is expected that the embodiments may be implemented in or associated with a variety of electronic devices. The various electronic devices are, for example, but not limited to, mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, video cameras, game consoles, watches, clocks, calculators, television monitors, flat-panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controls and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures, etc.

[0108] In summary, the pixel driving circuit and driving method thereof, the display panel, and the display device of the present invention have at least the following advantages:

[0109] The pixel driving circuit and driving method thereof, display panel, and display device disclosed in the embodiments of the present invention provide a second capacitor C2. By utilizing the capacitive coupling effect of the second capacitor C2, the leakage amount flowing from the second node N2 toward the third switching device T3 and the leakage amount flowing toward the sixth switching device T6 are reduced, thereby weakening the potential fluctuation at the N2 point, which is beneficial to improving the low-frequency flicker problem of OLED display products and enhancing their display effects.

[0110] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A pixel driving circuit, characterized in that: include: Light emitting element; A first initialization module, used to initialize the anode of the light emitting element; A second initialization module includes a first capacitor, and the second initialization module is used to initialize the first capacitor; A first charging module, connected to the preset data signal and the second initialization module respectively, and used to write the preset data signal into the first capacitor; A second charging module, comprising a second capacitor, wherein a first end of the second capacitor is respectively connected to the first charging module and the second initialization module; as well as The light-emitting driving module is respectively connected to the first initialization module, the second initialization module, the first charging module and the second charging module, and is used to drive the light-emitting element to emit light.

2. The pixel driving circuit according to claim 1, characterized in that: The pixel driving circuit further includes: The third initialization module is connected to the first initialization module and the light-emitting driving module respectively; the third initialization module and the light-emitting driving module are connected to form a first node, and the third initialization module is used to initialize the potential of the first node.

3. The pixel driving circuit according to claim 1 or 2, characterized in that: The first charging module includes a third switch device and a ninth switch device, the first electrode of the third switch device is connected to the first capacitor, the first electrode of the ninth switch device is connected to the preset data signal, and the second electrode of the third switch device is connected to the second electrode of the ninth switch device.

4. The pixel driving circuit according to claim 3, characterized in that: The light-emitting driving module includes a second switching device, and a gate of the second switching device is connected to a gate of the ninth switching device.

5. The pixel driving circuit according to claim 4, characterized in that: The gate of the second switching device, the gate of the ninth switching device and the first capacitor are connected to form a second node; when all the switching devices in the first charging module are turned on, a voltage corresponding to the preset data signal is written into the second node.

6. The pixel driving circuit according to claim 1 or 2, characterized in that: The first charging module includes a third switch device, a first electrode of the third switch device is connected to the first capacitor, and a second electrode of the third switch device is connected to the light-emitting driving module.

7. The pixel driving circuit according to claim 2, characterized in that: The third initialization module includes an eighth switch device, and a second electrode of the eighth switch device is connected to the light-emitting driving module to form a first node.

8. The pixel driving circuit according to claim 7, characterized in that: The first initialization module includes a seventh switching device, a gate of the seventh switching device and a gate of the eighth switching device are connected to the same scan signal, and a second electrode of the seventh switching device is connected to an anode of the light-emitting element.

9. The pixel driving circuit according to claim 1, wherein: The first charging module includes a third switching device, the second initialization module includes a sixth switching device, the third switching device and the sixth switching device are dual-gate transistors, and the second end of the second capacitor is connected between the source and the drain of the third switching device, and is connected between the source and the drain of the sixth switching device.

10. A pixel driving method, characterized in that: The pixel driving method is applied to the pixel driving circuit according to any one of claims 1 to 9, and the method comprises: Initializing the anode of the light-emitting element using the first initialization module; Initializing the first capacitor using the second initialization module; Using the first charging module to write the preset data signal into the first capacitor; Using the second charging module to achieve capacitive coupling; and The light-emitting driving module is used to drive the light-emitting element to emit light.

11. A display panel, characterized in that: The display panel comprises a pixel driving circuit as claimed in any one of claims 1 to 9.

12. A display device, characterized in that: Includes the display panel as claimed in claim 11.

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