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 its driving method, display panel and display device Technical Field

[0001] This invention relates to the field of display panel technology, and more specifically, to a pixel driving circuit and its driving method, a display panel, and a display device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) possess advantages such as low power consumption, low cost, self-emissiveness, wide viewing angle, and fast response speed, making them a current research hotspot in the display field. Electronic products employ different refresh rates in different application scenarios. For example, higher refresh rates are used to drive dynamic images to ensure smooth display, while lower refresh rates are used to drive static images to reduce power consumption. When using organic self-emissive technology in electronic products, flickering occurs at low refresh rates, affecting the visual experience.

[0003] It should be noted that the information disclosed in the background section above 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 those skilled in the art.

[0004] Summary of the Invention

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

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

[0007] Light-emitting elements;

[0008] The first initialization module is used to initialize the anode of the light-emitting element;

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

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

[0011] The second charging module includes a second capacitor, the first terminal of which is connected to both the first charging module and the second initialization module; and

[0012] The light-emitting driving module is connected to the first initialization module, the second initialization module, the first charging module, and the second charging module respectively, 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 both the first initialization module and the light-emitting driving module; 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, wherein 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, the gate of which is connected to the 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, the second node is written with a voltage corresponding to the preset data signal.

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

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

[0020] Optionally, the first initialization module includes a seventh switching device, the gate of the seventh switching device and the gate of the eighth switching device are connected to the same scan signal, and the 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, and the second initialization module includes a sixth switching device. The third and sixth switching devices are dual-gate transistors. The second terminal of the second capacitor is connected between the source and drain of the third switching device and between the source and drain of the sixth switching device.

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

[0023] The anode of the light-emitting element is initialized using the first initialization module;

[0024] The first capacitor is initialized using the second initialization module;

[0025] The preset data signal is written into the first capacitor using the first charging module;

[0026] Capacitive coupling is achieved using the second charging module; and

[0027] The light-emitting element is driven to emit light using the light-emitting driving module.

[0028] According to another aspect of the present invention, a display panel is provided, the display panel including any of the pixel driving circuits described above.

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

[0030] The advantages of this invention compared to the prior art are as follows:

[0031] The pixel driving circuit and driving method, display panel and display device provided by the present invention reduce the leakage current flowing from the second node N2 to the third switching device T3 and the leakage current flowing to the sixth switching device T6 by using the capacitive coupling effect of the second capacitor C2. This reduces the potential fluctuation at the N2 point, which helps to improve the low-frequency flicker problem of OLED display products and improve their display effect. Attached Figure Description

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0033] Figure 1 is a schematic diagram of the pixel driving circuit in the prior art;

[0034] Figure 2 is a schematic diagram of the brightness change between two adjacent frames of the pixel driving circuit in the prior art at a refresh rate of 60Hz;

[0035] Figure 3 is a schematic diagram of the brightness change between two adjacent frames of the pixel driving circuit in the prior art when the refresh rate is 30Hz;

[0036] Figure 4 is a schematic diagram of a pixel driving circuit disclosed in an embodiment of the present invention;

[0037] Figure 5 is a schematic diagram of a pixel driving circuit disclosed in another embodiment of the present invention;

[0038] Figure 6 is a schematic diagram of the working timing of the pixel driving circuit in Figure 5;

[0039] Figure 7 is a schematic diagram of a pixel driving circuit disclosed in another embodiment of the present invention;

[0040] Figure 8 is a schematic diagram of the working timing of the pixel driving circuit in Figure 7;

[0041] Figure 9 is a schematic diagram of a pixel driving circuit disclosed in another embodiment of the present invention. Detailed Implementation

[0042] Example embodiments will now be described more fully with reference to the accompanying drawings. However, these example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of the specific details described, or other methods, materials, apparatus, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring aspects of this disclosure. The same reference numerals in the figures denote the same or similar structures, and therefore their detailed descriptions are omitted.

[0043] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the presence of one or more elements / components / etc.; the terms “including,” “having,” and “have” are used to indicate an open-ended inclusion meaning and that other elements / components / etc. may exist 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 terminal (refer to the end of capacitor C1 near point N2 in Figure 1) is kept constant, a voltage is formed between the gate and source of the driving transistor (refer to transistor T2 in Figure 1), the driving transistor is controlled to form a driving current, and then the light-emitting diode is driven to emit light.

[0045] Referring to Figure 1, in the prior art, transistor T2, capacitor C1, and transistor T6 are connected together to form the second node N2. When the display panel is in a low refresh rate state, there is a leakage path at point N2, that is, during the light-emitting stage, the storage capacitor leaks current to other parts, causing the potential of the signal holding terminal of the storage capacitor to be unable to remain constant for a long time (i.e., the potential at point N2 changes significantly), which leads to instability of the driving current generated by the driving transistor, resulting in low-frequency flickering of the display panel.

[0046] Furthermore, visual flicker becomes more pronounced as the refresh rate decreases. Referring to the comparison of Figures 2 and 3, Figure 2 shows the brightness variation curve at a refresh rate of 60Hz, and Figure 3 shows the brightness variation curve at a refresh rate of 30Hz. △LV represents the difference in brightness variation between two adjacent frames. As shown in Figures 2 and 3, the brightness variation difference △LV1 at a refresh rate of 30Hz is greater than the brightness variation difference △LV2. That is, low-frequency flicker is more noticeable.

[0047] To address the aforementioned problems, an 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 driving module. The light-emitting driving module includes a light-emitting element. The light-emitting driving module is used 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 both the first charging module and the second initialization module. The light-emitting driving module is connected to the first initialization module, the second initialization module, the first charging module, and the second charging module.

[0048] In this embodiment, the first initialization module is used to initialize the anode of the light-emitting element. The second initialization module includes a first capacitor, which is used to initialize the first capacitor. The first charging module is connected to a preset data signal and is used to write the preset data signal into the first capacitor. The second charging module includes a second capacitor, the first terminal of which is connected to both the first charging module and the second initialization module. The light-emitting driving module is used to drive the 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 voltage fluctuations and leakage current at the second node N2.

[0049] In this embodiment, the first initialization module is respectively connected to the fourth scan signal S n+1 And the second reference voltage signal Vint2 is connected, and the second initialization module is connected to the second scan signal S respectively. 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 S, respectively.n Connections are made. The second charging module is connected to the aforementioned 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] Referring to Figure 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 switching device T7 is connected to the second reference voltage signal Vint2, and the second electrode of the seventh switching device T7 is connected to the light-emitting driving module. Specifically, the second electrode of the seventh switching device T7 is connected to the anode of the light-emitting element D1 in the light-emitting 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 gates of the first switching device T1 and the third switching device T3 are both connected to the third scan 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, of the second switching device T2 is connected to the aforementioned second initialization module to form the 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 shape of the second switching device T2 can be any shape, such as S-shaped, U-shaped, N-shaped, stepped, linear, or slash-shaped. However, to reduce optical problems caused by process fluctuations affecting the driving transistor T2, the second switching device T2 should have the largest possible linewidth and line length within the space accommodating the circuit.

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

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

[0055] Referring again to Figure 4, in this embodiment, the gate of the second switching device T2, the second terminal 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 terminal 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 switching device T1 and the third switching device T3 are turned on, the voltage corresponding to the preset data signal DATA is written to the second node N2.

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

[0057] In this embodiment, the second electrode of the third switching device T3 is connected to the aforementioned light-emitting driving 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 the third node N3. However, the present invention is not limited thereto. When both the first switching device T1 and the third switching device T3 are turned on, the third node N3 is written with a voltage corresponding to the aforementioned preset data signal DATA.

[0058] As can be seen from the above structure, the third scanning signal S n The first scan signal EM controls the on and off states of the first switching device T1 and the third switching device T3. The first scan signal EM controls the on and off states of the fourth switching device T4 and the fifth switching device T5. The fourth scan signal S... n+1 Controls the on / off state of the seventh switching device T7. Second scan signal S n-1 Controls the on and off states of the sixth switching device T6.

[0059] In this embodiment, both the third switching device T3 and the sixth switching device T6 are dual-gate transistors. As shown in Figure 4, node N4 is a point in the channel between the source and drain of the third switching device T3. Node N5 is a point in the channel between the source and drain of the sixth switching device T6.

[0060] Within the same frame period, the aforementioned third scan signal S n The time when the inactive signal transitions to the active signal is later than the second scan signal S mentioned above. n-1 The moment when the inactive level signal transitions to the active level signal, the aforementioned fourth scan signal S n+1 The time when the inactive signal transitions to the active signal is later than the third scan signal S mentioned above. n The moment when a non-invalid signal transitions to an valid signal.

[0061] The pixel driving circuit disclosed in the embodiment corresponding to FIG4 of the present invention, by adding a second capacitor C2, on the one hand, in the third scanning signal S n When the signal transitions from an effective level to an ineffective level, the capacitive coupling of the second capacitor C2 reduces the potential rise at node N4 in the third switching device T3. This reduces the voltage difference between node N4 and the second node N2, which helps reduce the leakage current flowing from the second node N2 to the third switching device T3. Consequently, it weakens the potential fluctuations at N2 and the brightness fluctuations of the light-emitting element D1, thus helping to improve the low-frequency flicker problem of OLED display products.

[0062] On the other hand, in the aforementioned second scan signal S n-1 When the signal changes from an effective level to an ineffective level, the capacitive coupling of the second capacitor C2 causes the potential of node N5 in the third switching device T6 to increase, thereby reducing the voltage difference between the second node N2 and node N5. This helps to reduce the leakage current flowing from the second node N2 to the third switching device T6, thus reducing the potential fluctuation at N2 and the brightness fluctuation of the light-emitting element D1, which helps to improve the low-frequency flicker problem of OLED display products.

[0063] In some optional embodiments, based on the embodiment corresponding to Figure 4 above, 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, that is, a positive power supply voltage output. The fifth reference voltage signal ELVSS is a negative potential, that is, 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. Furthermore, all switching devices in the circuit are of the same type, i.e., 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 effective level signal is low, and the ineffective level signal is high. When all are N-type thin-film transistors (N-type TFTs), the corresponding effective level signal is high, and the ineffective level signal is low.

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

[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 the source or the drain, and simultaneously satisfy the condition that the second electrode is either the source or the drain. That is, for example, when the first electrode is the source, then the second electrode is the drain. When the first electrode is the drain, then the second electrode is the source.

[0067] Another embodiment of the present invention discloses another pixel driving circuit. As shown in FIG. 5, based on the embodiment corresponding to FIG. 4, this embodiment further includes a third initialization module. The third initialization module is connected to both the first initialization module and the light-emitting driving module. The third initialization module is used 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 the 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 all connected 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 that of the first reference voltage signal Vint1. For example, the potential polarity of the first reference voltage signal Vint1 is negative, and the potential polarity of the third reference voltage signal Vint3 is positive.

[0070] Referring to Figure 6, this embodiment of the invention discloses a timing diagram of the pixel driving circuit corresponding to Figure 5. As shown in Figure 6, during the first time period (i.e., time period 1 in Figure 6), the first scanning signal EM and the second scanning signal S... n-1 Third scan signal S n and the fourth scan signal S n+1 Both are at 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 time period (i.e., time period 2 in Figure 6), the second scan signal S n-1 When the voltage level is low, the sixth switching device T6 is turned on. The voltage corresponding to the first reference voltage signal Vint1 is written into the first capacitor C1. The potential of the second node N2 is reset to the voltage corresponding to the first reference voltage signal Vint1, causing the second transistor T2 to turn on.

[0072] At the end of this second time period, that is, S n-1 During the voltage transition phase, the second capacitor C2 is subjected to the pull of the voltage connected to it, resulting in capacitive coupling. The capacitive coupling of the second capacitor C2 causes the potential of node N5 in the third switching device T6 to increase, thereby reducing the voltage difference between the second node N2 and node N5, which helps to reduce the leakage current flowing from the second node N2 to the third switching device T6.

[0073] During the third time period (i.e., time period 3 in Figure 6), 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.

[0074] In the fourth time period (i.e., time period 4 in Figure 6), the third scan signal S n When the voltage level is low, the first switching device T1 and the third switching device T3 are turned on. The voltage V corresponding to the preset data signal DATA is written to points N1 (first node), N2 (second node), and N3 (third node). DATA .

[0075] At the end of this fourth period, i.e., S n During the voltage transition phase, the second capacitor C2 is subjected to the pull of the voltage connected to it, resulting in capacitive coupling. The capacitive coupling of the second capacitor C2 reduces the potential rise of node N4 in the third switching device T3, thereby reducing the voltage difference between node N4 and the second node N2, which helps to reduce the leakage current flowing from the second node N2 to the third switching device T3.

[0076] During the fifth time period (i.e., time period 5 in Figure 6), 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.

[0077] In the sixth time period (i.e., time period 6 in Figure 6), the fourth scan signal S n+1 With the voltage low, the seventh switch T7 and the eighth switch T8 are turned on, and the anode of the light-emitting element D1 is reset to the 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 the voltage corresponding to the third reference voltage signal Vint3.

[0078] During the seventh time period (i.e., time period 7 in Figure 6), 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.

[0079] During the eighth time period (i.e., time period 8 in Figure 6), the first scanning 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] During the ninth time period (i.e., time period 9 in Figure 6), 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.

[0081] In the tenth time period (i.e., time period 10 in Figure 6), the fourth scan signal S n+1 With the voltage low, the seventh switch T7 and the eighth switch T8 are turned on, and the anode of the light-emitting element D1 is reset to the voltage corresponding to the second reference voltage signal Vint2. The potential of the first node N1 is reset to the voltage corresponding to the third reference voltage signal Vint3.

[0082] During the eleventh time period (i.e., time period 11 in Figure 6), the first scan signal EM is at a 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.

[0083] During the twelfth time period (i.e., time period 12 in Figure 6), the first scanning 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 Figure 5 of the present invention adds an eighth switching device T8 at the first node N1, such that the first scanning signal EM is high and the fourth scanning signal S n+1When the voltage is low, the eighth switch device T8 is turned on. The conduction path of the third reference voltage signal Vint3 is as follows: it is conducted sequentially through the eighth switch device T8, the first node N1, and the second switch device T2 to the third node N3. This resets the potentials of both N1 and N3 to the voltage corresponding to the third reference voltage signal Vint3. On the one hand, this can reduce the hysteresis effect of the second switch device T2 (i.e., the driving transistor) on the flicker. On the other hand, after the potential of N3 is rewritten, it can reduce the potential change of N4 caused by the leakage of T3b (the third switch device T3 includes T3a and T3b), reduce the voltage difference between the midpoint N4 of the third switch device T3 and the second node N2, improve the potential fluctuation of N2, thereby improving the low-frequency flicker problem of the display panel and enhancing the display effect.

[0085] Another embodiment of the present invention discloses another pixel driving circuit. As shown in FIG. 7, based on the embodiment corresponding to FIG. 4 above, 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. The difference between this embodiment and the embodiment corresponding to FIG. 4 above is that the second electrode of the third switching device T3 is connected to the second electrode of the ninth switching device T9, instead of being connected to the light-emitting driving module. Furthermore, the third switching device T3 and the ninth switching device T9 are connected to form 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 terminal 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 transmission path of the voltage corresponding to the preset data signal DATA is as follows: sequentially written to node N2 via the first switching device T1, the ninth switching device T9, node N3', the fourth node N4, and the third switching device T3.

[0087] Referring to Figure 8, this embodiment of the invention discloses a schematic diagram of the working timing of the pixel driving circuit corresponding to Figure 7. As shown in Figure 8, in the first time period (i.e., time period 1 in Figure 8), 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, that is, the light-emitting element D1 is in the off state.

[0088] In the second time period (i.e., time period 2 in Figure 8), the second scan signal S n-1When the voltage level is low, the sixth switching device T6 is turned on. The voltage corresponding to the first reference voltage signal Vint1 is written into the first capacitor C1. The potential of the second node N2 is reset to the voltage corresponding to the first reference voltage signal Vint1, causing the second transistor T2 to turn on.

[0089] In the third time period (i.e., time period 3 in Figure 8), the third scan signal S n When the voltage is low, the first switching device T1 and the third switching device T3 are turned on. Nodes N3', N4, and N2 are all written with the voltage V corresponding to the preset data signal DATA. DATA .

[0090] In the fourth time period (i.e., time period 4 in Figure 8), the fourth scan signal S n+1 When the voltage is low, the seventh switching 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] During the fifth time period (i.e., time period 5 in Figure 8), 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.

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

[0093] The embodiment corresponding to Figure 7 of the present invention sets a second capacitor C2 and a ninth switching device T9 in the circuit so that after charging, that is, after the preset data signal DATA is written to node N3', the fourth node N4 and the second node N2, the potentials of N4 and N2 are equal. Then the voltage difference between the third switching device T3 and the sixth switching device T6 is zero, thereby reducing the leakage current at N2 and thus helping to improve the low-frequency flicker problem of OLED display products.

[0094] Another embodiment of the present invention discloses another pixel driving circuit. As shown in FIG. 9, based on the embodiment corresponding to FIG. 7, this embodiment further includes a third initialization module. The third initialization module is connected to both the first initialization module and the light-emitting driving module. The third initialization module is used 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 the 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 all connected 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 timing diagram of the pixel driving circuit in this embodiment can be found in Figure 6.

[0096] The pixel driving circuit disclosed in the embodiment corresponding to FIG9 of the present invention adds an eighth switching device T8 at the first node N1, such that the first scanning signal EM is high and the fourth scanning signal S n+1 When the voltage is low, 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 hysteresis effect of the second switching device T2, i.e. the driving transistor, on flicker, which helps to improve the low-frequency flicker problem of the display panel and improve the display effect.

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

[0098] S110, the anode of the light-emitting element is initialized using the first initialization module.

[0099] S120, the first capacitor is initialized using the second initialization module.

[0100] S130, the preset data signal is written into the first capacitor using the first charging module.

[0101] S140 utilizes a second charging module to achieve capacitive coupling.

[0102] S150, the light-emitting element is driven to emit light using a light-emitting driving module.

[0103] One frame cycle of 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 also discloses a display panel, which includes the pixel driving circuit disclosed in any of the above embodiments. Detailed structural features and advantages of the pixel driving circuit can be found in the descriptions 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 this application can improve the problem of uneven display caused by uneven brightness of multiple light-emitting elements, reduce visual flicker, and thus improve the display effect.

[0106] Some embodiments of this disclosure also provide a display device, which includes the above-described display panel.

[0107] The display device provided in this disclosure can be any device that displays images, whether moving (e.g., video) or fixed (e.g., still images), and whether it contains text or images. More specifically, the embodiments described are contemplated to be implemented in or associated with a variety of electronic devices. These various electronic devices include, but are not limited to, mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers 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, display panel, and display device of the present invention have at least the following advantages:

[0109] The pixel driving circuit and driving method, display panel and display device disclosed in the embodiments of the present invention reduce the leakage current flowing from the second node N2 to the third switching device T3 and the leakage current flowing to the sixth switching device T6 by setting a second capacitor C2 and utilizing the capacitive coupling effect of the second capacitor C2. This reduces the potential fluctuation at the N2 point, which helps to improve the low-frequency flicker problem of OLED display products and improve their display effect.

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

Claims

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

2. The pixel driving circuit as described in claim 1, characterized in that, The pixel driving circuit also includes: The third initialization module is connected to both the first initialization module and the light-emitting driving module; 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 as described in claim 1 or 2, characterized in that, 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.

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

5. The pixel driving circuit as described in 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 switching devices in the first charging module are turned on, the second node is written with a voltage corresponding to the preset data signal.

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

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

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

9. The pixel driving circuit as described in claim 1, characterized in that, The first charging module includes a third switching device, and the second initialization module includes a sixth switching device. The third and sixth switching devices are dual-gate transistors. The second terminal of the second capacitor is connected between the source and drain of the third switching device and between the source and 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 as described in any one of claims 1-9, and the method includes: The anode of the light-emitting element is initialized using the first initialization module; The first capacitor is initialized using the second initialization module; The preset data signal is written into the first capacitor using the first charging module; Capacitive coupling is achieved using the second charging module; and The light-emitting element is driven to emit light using the light-emitting driving module.

11. A display panel, characterized in that, The display panel includes a pixel driving circuit as described in any one of claims 1-9.

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

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