Pixel driving circuit and driving method thereof, display panel and display device
Patent Information
- Application Number
- CN202510494817.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2026-10-23
AI Technical Summary
尤其在低刷新频率显示时，由于两帧间隔时间长，亮度的降低会出现人眼可识别的明显的闪烁，造成用户的观感体验不佳
[0036]本发明提供的像素驱动电路中通过设置电位稳定单元，用于稳定因控制信号变化引起的第一节点N1的电位波动，进而减小在发光阶段发光元件的亮度变化，改善低刷新频率下显示面板出现的明显的闪烁问题。
Smart Images
Figure CN122967591A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of display technology, specifically to a pixel driving circuit and its driving method, a display panel, and a display device. Background Technology
[0002] Organic light-emitting display (OLED) devices have many advantages, such as being all-solid-state, self-emissive, having a wide viewing angle, a wide color gamut, fast response speed, high luminous efficiency, high brightness, high contrast, ultra-thinness, ultra-lightness, low power consumption, a wide operating temperature range, the ability to manufacture large-size and flexible panels, and simple manufacturing processes. They can realize truly flexible displays and have received increasing attention and importance in the market in recent years.
[0003] In the existing technology, OLED light emission display is driven by pixel driving circuits. Figure 1 and Figure 2 An equivalent schematic diagram and driving timing diagram of an existing pixel driving circuit are shown respectively. Figure 1 As shown, the pixel driving circuit includes a first initialization unit 1', a data writing unit 2', a compensation unit 3', a second initialization unit 4', a storage capacitor C1', a driving transistor T9', and a light-emitting control unit 5', wherein each unit is composed of transistors, according to... Figure 2 The driving timing shown indicates that each transistor is turned on sequentially to drive the OLED light-emitting element to emit light. Figure 3 This diagram illustrates the change in brightness over time for an existing OLED display, with the horizontal axis representing time and the vertical axis representing brightness. Figure 3 As shown, the brightness of the OLED light-emitting element gradually decreases over time during a single frame display. Especially at low refresh rates, the long interval between frames causes a noticeable flicker that is perceptible to the human eye, resulting in a poor viewing experience for the user. Summary of the Invention
[0004] To address the problems in the prior art, the present invention aims to provide a pixel driving circuit and its driving method, a display panel and a display device, thereby improving the obvious flickering problem that occurs when the display panel is displayed at a low refresh rate.
[0005] This invention provides a pixel driving circuit, comprising:
[0006] A driving transistor and a first capacitor, wherein the control terminal of the driving transistor is electrically connected to the first capacitor through a first node;
[0007] A first initialization unit, in response to a first scan signal or a second scan signal, initializes the potential of the first node and the first terminal of the light-emitting element with a first initialization voltage;
[0008] A data writing unit and a compensation unit, wherein the data writing unit and the compensation unit respond to the second scan signal to write the data voltage and the threshold voltage of the driving transistor to the first node and store them in the first capacitor;
[0009] A potential stabilization unit is electrically connected to the first node; the potential stabilization unit responds to a third scan signal to stabilize the potential of the first node;
[0010] The light-emitting control unit responds to the light-emitting control signal to drive the light-emitting element to emit light.
[0011] In some embodiments, the potential stabilization unit includes a second capacitor and a first transistor. The first terminal of the second capacitor is electrically connected to a first power supply voltage signal line, and the second terminal of the second capacitor is electrically connected to the first terminal of the first transistor through a second node. The control terminal of the first transistor is electrically connected to a third scan signal line, and the second terminal of the first transistor is electrically connected to the first node. The control terminal of the driving transistor is electrically connected to the first node or the second node.
[0012] In some embodiments, the potential stabilization unit includes a first transistor, the control terminal of the first transistor is electrically connected to a third scan signal line, the first terminal of the first transistor is electrically connected to the first node, the second terminal of the first transistor is electrically connected to the control terminal of the driving transistor, and the first terminal and the second terminal of the first transistor are electrically connected.
[0013] In some embodiments, the first initialization unit includes a second transistor, the control terminal of the second transistor is electrically connected to a first scan signal line, the first terminal of the second transistor is electrically connected to a first initialization voltage signal line, and the second terminal of the second transistor is electrically connected to the first node.
[0014] In some embodiments, the first initialization unit further includes a third transistor, the control terminal of which is electrically connected to the second scan signal line, the first terminal of which is electrically connected to the first terminal of the second transistor, and the second terminal of which is electrically connected to the first terminal of the light-emitting element.
[0015] In some embodiments, the data writing unit includes a fourth transistor, the control terminal of the fourth transistor being electrically connected to the second scan signal line, the first terminal of the fourth transistor being electrically connected to the data line, and the second terminal of the fourth transistor being electrically connected to the first terminal of the driving transistor.
[0016] In some embodiments, the compensation unit includes a fifth transistor, the control terminal of the fifth transistor being electrically connected to the second scan signal line, the first terminal of the fifth transistor being electrically connected to the first node, and the second terminal of the fifth transistor being electrically connected to the second terminal of the driving transistor.
[0017] In some embodiments, a second initialization unit is further included, which initializes the first and second terminals of the driving transistor with a second initialization voltage in response to a fourth scan signal.
[0018] In some embodiments, the second initialization unit includes a sixth transistor, the control terminal of the sixth transistor being electrically connected to a fourth scan signal line, the first terminal of the sixth transistor being electrically connected to a second initialization voltage signal line, and the second terminal of the sixth transistor being electrically connected to the first terminal of the driving transistor.
[0019] In some embodiments, the light-emitting control unit includes a seventh transistor and an eighth transistor, wherein,
[0020] The control terminal of the seventh transistor is electrically connected to the light emission control signal line, the first terminal of the seventh transistor is electrically connected to the first power supply voltage signal line, and the second terminal of the seventh transistor is electrically connected to the first terminal of the driving transistor.
[0021] The control terminal of the eighth transistor is electrically connected to the light-emitting control signal line, the first terminal of the eighth transistor is electrically connected to the second terminal of the driving transistor, and the second terminal of the eighth transistor is electrically connected to the first terminal of the light-emitting element.
[0022] The second end of the light-emitting element is electrically connected to the second power supply voltage signal line.
[0023] This invention also provides a method for driving a pixel driving circuit, used to drive the pixel driving circuit described above, the method comprising the following steps:
[0024] In the first initialization phase, the first scan signal and the third scan signal are at the working level, and the first initialization voltage initializes the potential of the first node and the first terminal of the potential stabilization unit;
[0025] During the data writing and threshold compensation phases, the second scan signal is at the working level, writing the data voltage and the threshold voltage of the driving transistor to the first node and storing them in the first capacitor;
[0026] During the potential stabilization phase, the third scanning signal is at the working level to stabilize the potential of the first node;
[0027] During the light-emitting phase, the light-emitting control signal is at the operating level, driving the light-emitting element to emit light.
[0028] This invention also provides a method for driving a pixel driving circuit, used to drive the pixel driving circuit described above, the method comprising the following steps:
[0029] In the first initialization phase, the first scan signal is at the working level, and the potential of the first node is initialized with the first initialization voltage;
[0030] During the data writing and threshold compensation phases, the second scan signal is at the working level, writing the data voltage and the threshold voltage of the driving transistor to the first node and storing them in the first capacitor;
[0031] During the potential stabilization phase, the third scanning signal is at the working level to stabilize the potential of the first node;
[0032] During the light-emitting phase, the light-emitting control signal is at the operating level, driving the light-emitting element to emit light.
[0033] This invention also provides a display panel, including the pixel driving circuit described above.
[0034] This invention also provides a display device, including the pixel driving circuit described above.
[0035] The pixel driving circuit and driving method, display panel, and display device provided by this invention have the following advantages:
[0036] The pixel driving circuit provided by the present invention uses a potential stabilization unit to stabilize the potential fluctuation of the first node N1 caused by the change of control signal, thereby reducing the brightness change of the light-emitting element during the light-emitting stage and improving the obvious flickering problem of the display panel at low refresh rate. Attached Figure Description
[0037] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.
[0038] Figure 1 This is a schematic diagram of a pixel driving circuit in the prior art;
[0039] Figure 2 yes Figure 1 The corresponding driver timing diagram;
[0040] Figure 3 This is a graph showing the change in brightness of the OLED light-emitting element over time during low-frequency display in existing technologies.
[0041] Figure 4 This is an equivalent schematic diagram of a pixel driving circuit according to an embodiment of the present invention;
[0042] Figure 5 This is a timing diagram of the pixel driving circuit in an embodiment of the present invention during frame writing;
[0043] Figure 6 This is a timing diagram of the pixel driving circuit in a frame holding mode according to an embodiment of the present invention;
[0044] Figure 7 yes Figure 4 A schematic diagram of the pixel driving circuit injecting electrons into the first node during the fourth working time period;
[0045] Figure 8 This is an equivalent schematic diagram of a pixel driving circuit according to another embodiment of the present invention;
[0046] Figure 9 This is an equivalent schematic diagram of a pixel driving circuit according to another embodiment of the present invention;
[0047] Figure 10 yes Figure 9 The timing diagram of the pixel driving circuit during frame writing;
[0048] Figure 11 yes Figure 9 A schematic diagram of the pixel driving circuit injecting electrons into the first node during the fourth working time period. Detailed Implementation
[0049] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted. The words “or” and “or” in the specification may mean “and” or “or”.
[0050] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics represented in connection with that embodiment or example, which are included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics represented may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate different embodiments or examples represented in this application, as well as features of different embodiments or examples.
[0051] Furthermore, the terms "first" and "second" are used for illustrative purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the representation of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0052] Figure 1 The pixel driving circuit shown causes the brightness of the OLED to gradually decrease over time during the display of one frame. This is because when the second transistor T2' in the first initialization unit 1' and the fifth transistor T5' in the compensation unit 3' are turned off, the first scan signal Sn-1' controlling the shutdown of the second transistor T2' and the second scan signal Sn' controlling the shutdown of the fifth transistor T5' change from low to high. Under the influence of the high-level signal, some holes in the channels of the second transistor T2' and the fifth transistor T5' are repelled into the first node N1', thus causing the potential at the first node N1' to rise, thereby causing the brightness of the OLED to decrease over time. It should be noted here that... Figure 1 The transistors shown are P-type transistors. When the control terminal of a P-type transistor is high, the P-type transistor is off; otherwise, it is on. However, if all P-type transistors are replaced with N-type transistors, when the N-type transistors switch from on to off, the scanning signal at their control terminal changes from high to low. At this time, electrons in the channel of the N-type transistor are repelled into the first node N1' under the influence of the low level, causing the potential of the first node N1' to drop. This results in the brightness of the OLED light-emitting element decreasing over time during the display of one frame.
[0053] To address the problem that the brightness of the light-emitting element decreases over time during the display of a single frame in existing pixel driving circuits, this invention provides a pixel driving circuit that solves the aforementioned problem. Figure 4 A pixel driving circuit according to an embodiment of the present invention is shown, such as Figure 4 As shown, the pixel driving circuit includes a first initialization unit 1, a data writing unit 2, a compensation unit 3, a light emission control unit 5, a potential stabilization unit 6, a first capacitor C1, and a driving transistor T9.
[0054] Specifically, the control terminal of the driving transistor T9 is electrically connected to the first capacitor C1 through the first node N1; the first initialization unit 1, in response to the first scan signal Sn-1 or the second scan signal Sn, initializes the potential of the first node N1 and the first terminal of the light-emitting element OLED with the first initialization voltage Vint1. The data writing unit 2 and the compensation unit 3, in response to the second scan signal Sn, write the data voltage Vdata and the threshold voltage Vth of the driving transistor T9 to the first node N1 and store them in the first capacitor C1. The potential stabilization unit 6, in response to the third scan signal Cn, stabilizes the potential of the first node N1. The light-emitting control unit 5, in response to the light-emitting control signal En, drives the light-emitting element OLED to emit light.
[0055] Please continue reading. Figure 4 The potential stabilization unit 6 includes a second capacitor C2 and a first transistor T1. The first terminal of the second capacitor C2 is electrically connected to the first power supply voltage signal line, and the second terminal of the second capacitor C2 is electrically connected to the first terminal of the first transistor T1 through a second node N2. The second terminal of the first transistor T1 is electrically connected to the first node N1. The control terminal of the driving transistor T9 is electrically connected to the second node N2. The first power supply voltage signal line provides a first power supply voltage ELVDD, which is a positive power supply voltage. When the third scan signal Cn is at the operating level, the first transistor T1 is turned on, at which time the first node N1 and the second node N2 are also turned on.
[0056] When the first scan signal Sn-1 and the second scan signal Sn change from the working level to the non-working level, the transistors in the first initialization unit 1 and the compensation unit 3 change from being on to being off. When the transistor is on, the first charge in its channel will enter the first node N1 under the influence of the non-working level, thus causing the potential of the first node N1 to change. When the third scan signal Cn is made to the working level, the first transistor T1 will be turned on, and part of the second charge in the channel of the first transistor T1 will enter the first node N1 and neutralize with the first charge, thereby stabilizing the potential of the first node N1. The charge entering the first node N1 will also be redistributed between the first capacitor C1 and the second capacitor C2, further stabilizing the potential of the first node N1. The potential at the first node N1 is stable and the potential fluctuation is small. Therefore, the brightness of the OLED light-emitting element changes little over time during the light-emitting stage of a single frame display, thereby improving the obvious flickering problem of the display panel when displaying at low refresh rates.
[0057] Please continue reading. Figure 4 The pixel driving circuit also includes a second initialization unit 4. In response to the fourth scan signal Rn, the second initialization unit 4 initializes the potentials of the first and second terminals of the driving transistor T9 with the second initialization voltage Vint2, that is, improves the voltage bias of the first and second terminals of the driving transistor T9.
[0058] Furthermore, embodiments of this application also provide a driving method for a pixel driving circuit, used to drive the pixel driving circuit as described above. The driving method includes the following steps:
[0059] In the first initialization phase, the first scan signal Sn-1 and the third scan signal Cn are at the working level, and the first initialization voltage Vint initializes the potential of the first node N1 and the first terminal of the potential stabilization unit 6; the first terminal of the potential stabilization unit 6 is the connection node between the second capacitor C2 and the first transistor T1, which is the second node N2 in this embodiment, and can also be regarded as the second terminal of the second capacitor C2.
[0060] During the data writing and threshold compensation stages, the second scan signal Sn is at the working level, writing the data voltage Vdata and the threshold voltage Vth of the driving transistor T9 to the first node N1 and storing them in the first capacitor C1.
[0061] During the potential stabilization phase, the third scan signal Cn is at the working level to stabilize the potential of the first node N1;
[0062] During the light-emitting stage, the light-emitting control signal En is at the working level, driving the OLED light-emitting element to emit light.
[0063] When the pixel driving circuit also includes a second initialization unit 4, the driving method further includes the following steps:
[0064] During the second initialization phase, the fourth scan signal Rn is at the working level, and the second initialization voltage Vint2 initializes the potentials of the first and second terminals of the driving transistor T9 to improve the bias of the first and second terminals of the driving transistor T9.
[0065] Specifically, such as Figure 4 As shown, the first initialization unit 1 includes a second transistor T2. The control terminal of the second transistor T2 is electrically connected to the first scan signal line, the first terminal of the second transistor T2 is electrically connected to the first initialization voltage signal line, and the second terminal of the second transistor T2 is electrically connected to the first node N1. The first scan signal line provides a first scan signal Sn-1, and the first initialization voltage signal line provides a first initialization voltage Vint1.
[0066] Furthermore, the first initialization unit 1 also includes a third transistor T3. The control terminal of the third transistor T3 is electrically connected to the second scan signal line, the first terminal of the third transistor T3 is electrically connected to the first terminal of the second transistor T2, and the second terminal of the third transistor T3 is electrically connected to the first terminal of the light-emitting element OLED. The second scan signal line provides the second scan signal Sn.
[0067] The data writing unit 2 includes a fourth transistor T4. The control terminal of the fourth transistor T4 is electrically connected to the second scan signal line, the first terminal of the fourth transistor T4 is electrically connected to the data line, and the second terminal of the fourth transistor T4 is electrically connected to the first terminal of the driving transistor T9. The data line provides a data voltage V. DATA .
[0068] The compensation unit 3 includes a fifth transistor T5. The control terminal of the fifth transistor T5 is electrically connected to the second scan signal line, the first terminal of the fifth transistor T5 is electrically connected to the first node N1, and the second terminal of the fifth transistor T5 is electrically connected to the second terminal of the driving transistor T9. In this embodiment, the second transistor and the fifth transistor T5 are dual-gate transistors. When the dual-gate transistor is turned off, it can reduce the fluctuation of the first node N1, but it is not limited to this.
[0069] The second initialization unit 4 includes a sixth transistor T6. The control terminal of the sixth transistor T6 is electrically connected to the fourth scan signal line, the first terminal of the sixth transistor T6 is electrically connected to the second initialization voltage signal line, and the second terminal of the sixth transistor T6 is electrically connected to the first terminal of the driving transistor T9. The fourth scan signal line provides the fourth scan signal Rn, and the second initialization voltage signal line provides the second initialization voltage Vint2.
[0070] The light-emitting control unit 5 includes a seventh transistor T7 and an eighth transistor T8, wherein,
[0071] The control terminal of the seventh transistor T7 is electrically connected to the light emission control signal line, the first terminal of the seventh transistor T7 is electrically connected to the first power supply voltage signal line, and the second terminal of the seventh transistor T7 is electrically connected to the first terminal of the driving transistor T9.
[0072] The control terminal of the eighth transistor T8 is electrically connected to the light-emitting control signal line, the first terminal of the eighth transistor T8 is electrically connected to the second terminal of the driving transistor T9, and the second terminal of the eighth transistor T8 is electrically connected to the first terminal of the light-emitting element OLED. The light-emitting control signal line provides the light-emitting control signal En.
[0073] The second end of the light-emitting element OLED is electrically connected to the second power supply voltage signal line, which provides the second power supply voltage ELVSS, and the second power supply voltage ELVSS is a negative power supply voltage.
[0074] The transistors used in the embodiments of this invention can be thin-film transistors, field-effect transistors, or other devices with similar characteristics. Based on their characteristics, transistors can be classified into N-type and P-type; the following embodiments use P-type transistors for illustration. In the embodiments of this invention, the control terminal is the gate, the first or second terminal is the source, and the first or second terminal is the drain. When a low level is input to the gate of the P-type transistor, the source and drain are turned on. It should be noted that, in the embodiments of this invention, assuming all transistors are P-type, the operating level refers to the effective level at which the P-type transistor is turned on, i.e., a low level; the non-operating level refers to a high level.
[0075] Combination Figure 4 and Figure 5 When a written frame is displayed, the driving method of the pixel driving circuit described above includes the following steps:
[0076] During the first time period t1 (first initialization phase), the first scan signal Sn-1 is at the working level (low level), and the second transistor T2 is turned on; the third scan signal Cn is at the working level (low level), and the first transistor T1 is turned on; the first initialization voltage Vint1 is transmitted to the first node N1 through the second transistor T2, and the first initialization voltage Vint1 is transmitted to the second node N2 through the first transistor T1. The first initialization voltage Vint1 initializes the potentials of the first node N1 and the second node N2 so that the potentials of the first node N1 and the second node N2 are the same; it should be noted that the first initialization voltage Vint1 is a negative voltage signal, therefore, when the first initialization voltage Vint1 is transmitted to the second node N2, the driving transistor T9 can be turned on.
[0077] During the second time period t2 (data writing and compensation phase), the second scan signal Sn is at the working level (low level), and the third transistor T3, the fourth transistor T4, and the fifth transistor T5 are turned on. The first initialization voltage Vint1 is transmitted to the first terminal of the light-emitting element OLED through the third transistor T3 to initialize the potential of the first terminal of the light-emitting element OLED and improve the bias voltage of the light-emitting element OLED; at the same time, the data voltage V DATA The threshold voltage Vth of the driving transistor T9 is written to the first node N1 and stored in the first capacitor C1. For example... Figure 7 As shown, when the second scan signal Sn is at a high level, the second transistor T2 and the fifth transistor T5 are turned off, which will correspondingly raise the potential of the first node N1, that is, inject holes into the first node N1, causing the potential of node N1 to rise.
[0078] During the third time period t3 (second initialization phase), the fourth scan signal Rn is at the working level (low level), the sixth transistor T6 is turned on, and the second initialization voltage Vint2 is transmitted through the sixth transistor T6 to the two ends of the driving transistor T9 to initialize the potential at the two ends of the driving transistor T9. It should be noted here that during the first initialization phase, the driving transistor T9 is in the conducting state under the action of the second node N2. Therefore, when the driving transistor T9 is in the conducting state, the second initialization voltage Vint2 is written to the first end of the driving transistor T9 and transmitted to the second end of the driving transistor T9, improving the voltage bias between the first and second ends of the driving transistor T9.
[0079] During the fourth time period t4 (the potential stabilization phase), the third scan signal Cn is at the working level (low level), and the first transistor T1 is turned on; as Figure 7 As shown, under the low level of the third scan signal Cn, the potentials of the first and second terminals of the first transistor T1 will be pulled down accordingly, that is, electrons will be injected into the first and second terminals of the first transistor T1. The holes injected into the first node N1 when the second transistor T2 and / or the fifth transistor T5 are turned off will be neutralized with the electrons injected into the first node N1 when the first transistor T1 is turned on, thereby reducing the number of holes entering the first node N1, reducing the potential rise of the first node N1, and achieving the effect of stabilizing the potential of the first node N1.
[0080] During the fifth time period t5 (light-emitting stage), the light-emitting control signal En is at the working level (low level), and the seventh transistor T7 and the eighth transistor T8 are turned on, driving the OLED light-emitting element to emit light. During the light-emitting stage, the first capacitor C1 and the second capacitor C2 are connected in parallel to maintain the potential of the first node N1, which can further reduce the fluctuation of the potential of the first node N1.
[0081] By setting a potential stabilization unit 6 before the light-emitting stage is turned on, holes in the channels of the second transistor T2 and the fifth transistor T5 can enter the first node N1 when they are turned off. By turning on the first transistor T1, electrons in the channel of the first transistor T1 move towards the first node N1, and electrons and holes undergo a neutralization reaction, thereby reducing the potential rise of the first node N1 and stabilizing the potential of the first node N1. Therefore, the OLED light-emitting element can reduce the potential fluctuation of the first node N1 when displaying a frame, reduce the brightness change over time when the OLED light-emitting element emits light, and improve the obvious flickering problem that occurs in the display panel when displaying at low frequencies.
[0082] It should be noted that the number of electrons entering the first node N1 when the first transistor T1 is turned on is related to the length and width of the channel of the first transistor T1. Therefore, by adjusting the width-to-length ratio of the channel of the first transistor T1, the holes that are repelled from entering the first node N1 can be completely neutralized, thereby eliminating the influence of holes on the potential of the first node N1 in the traditional circuit.
[0083] In some embodiments, a hold frame is provided between two write frames when displaying at a low refresh rate. Figure 6 The driving timing of a pixel driving circuit in a frame-holding manner according to an embodiment of the present invention is shown. For example... Figure 6 As shown, compared with the write frame timing, the first scan signal Sn-1 and the second scan signal Sn have no working level signals in the write frame. The other working signals are the same as in the write frame. You can refer to the working of the write frame. It will not be described again here.
[0084] like Figure 8 As shown, another embodiment of this application also provides a schematic diagram of a pixel driving circuit. (See diagram below.) Figure 8 As shown, with Figure 4 The difference in the pixel driving circuit shown is that, in this embodiment, the control terminal of the driving transistor T9 is directly electrically connected to the first node N1, and the rest are configured the same as... Figure 4 The pixel driving circuit is configured in the same way, and the same technical effect as the above embodiment can be achieved. The specific principle is the same as the above embodiment, and will not be repeated here.
[0085] Figure 9 A schematic diagram of a pixel driving circuit is shown in yet another embodiment of this application. Figure 9 The pixel driving circuit shown is, with Figure 4 and Figure 8 The difference from the pixel driving circuit is that, in this embodiment, the potential stabilization unit 6 includes a first transistor T1, the control terminal of the first transistor T1 is electrically connected to the third scan signal line, and the first terminal of the first transistor T1 is electrically connected to the second terminal, that is, the source and drain of the first transistor T1 are short-circuited.
[0086] Figure 10 It shows Figure 9 The driving timing diagram of the pixel driving circuit is shown. Figure 5 and Figure 6 Compared to the driving timing, Figure 10 The on-time of the third scan signal Cn differs in the driving timing, while the on-time of the other signals is the same. Therefore, this section only describes the timing of the third scan signal Cn.
[0087] like Figure 10As shown, during the first time period t1 to the third time period t3, the third scan signal Cn is at a high level, meaning the first transistor T1 is off; during the fourth time period t4, the third scan signal Cn is at a working level (low level), meaning the first transistor T1 is on. Figure 11 As shown, when the third scan signal Cn is at a low level, the potential at the source and drain terminals of the first transistor T1 is pulled down, that is, electrons are injected at the source and drain terminals of the first transistor T1. One end of the first transistor T1 is electrically connected to the first node N1, so the injected electrons will enter the first node N1 accordingly. When the second transistor T2 and the fifth transistor T5 are turned off, the holes injected into the first node N1 will be neutralized with the electrons injected into the first node N1, thereby stabilizing the potential of the first node N1, making the potential fluctuation of the first node N1 during the light-emitting stage small, improving the flickering problem of the display panel at low refresh rates, and enhancing the user experience.
[0088] In this embodiment, the potential of the first node N1 can also be stabilized by adjusting the aspect ratio of the first transistor T1 to ensure that the holes injected into the first node N1 are completely absorbed.
[0089] This application also provides a display panel, including the pixel driving circuit described above. The display panel achieves all the technical effects of the pixel driving circuit described above, and will not be repeated here.
[0090] This application also provides a display device, including the display panel described above. The display device can be a mobile phone, tablet, mobile phone, billboard, desktop computer, etc., and can achieve all the technical effects achieved by the above display panel, which will not be repeated here.
[0091] In summary, the pixel driving circuit and driving method, display panel, and display device provided by the present invention have the following advantages:
[0092] By setting a potential stabilization unit, the potential fluctuation of the first node N1 caused by changes in the control signal level is stabilized, thereby reducing the brightness change of the light-emitting element during the light-emitting stage and improving the obvious flickering problem of the display panel at low refresh rates.
[0093] 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: A driving transistor and a first capacitor, wherein the control terminal of the driving transistor is electrically connected to the first capacitor through a first node; A first initialization unit, in response to a first scan signal or a second scan signal, initializes the potential of the first node and the first terminal of the light-emitting element with a first initialization voltage; A data writing unit and a compensation unit, wherein the data writing unit and the compensation unit respond to the second scan signal to write the data voltage and the threshold voltage of the driving transistor to the first node and store them in the first capacitor; A potential stabilization unit is electrically connected to the first node; The potential stabilization unit responds to the third scan signal to stabilize the potential of the first node; The light-emitting control unit responds to the light-emitting control signal to drive the light-emitting element to emit light.
2. The pixel driving circuit according to claim 1, characterized in that, The potential stabilization unit includes a second capacitor and a first transistor. The first terminal of the second capacitor is electrically connected to a first power supply voltage signal line, and the second terminal of the second capacitor is electrically connected to the first terminal of the first transistor through a second node. The control terminal of the first transistor is electrically connected to a third scan signal line, and the second terminal of the first transistor is electrically connected to the first node. The control terminal of the driving transistor is electrically connected to the first node or the second node.
3. The pixel driving circuit according to claim 1, characterized in that, The potential stabilization unit includes a first transistor, the control terminal of the first transistor is electrically connected to the third scan signal line, the first terminal of the first transistor is electrically connected to the first node, the second terminal of the first transistor is electrically connected to the control terminal of the driving transistor, and the first terminal and the second terminal of the first transistor are electrically connected.
4. The pixel driving circuit according to claim 2 or 3, characterized in that, The first initialization unit includes a second transistor, the control terminal of the second transistor is electrically connected to the first scan signal line, the first terminal of the second transistor is electrically connected to the first initialization voltage signal line, and the second terminal of the second transistor is electrically connected to the first node.
5. The pixel driving circuit according to claim 4, characterized in that, The first initialization unit further includes a third transistor, the control terminal of which is electrically connected to the second scan signal line, the first terminal of which is electrically connected to the first terminal of the second transistor, and the second terminal of which is electrically connected to the first terminal of the light-emitting element.
6. The pixel driving circuit according to claim 5, characterized in that, The data writing unit includes a fourth transistor, the control terminal of which is electrically connected to the second scan signal line, the first terminal of which is electrically connected to the data line, and the second terminal of which is electrically connected to the first terminal of the driving transistor.
7. The pixel driving circuit according to claim 6, characterized in that, The compensation unit includes a fifth transistor, the control terminal of which is electrically connected to the second scan signal line, the first terminal of which is electrically connected to the first node, and the second terminal of which is electrically connected to the second terminal of the driving transistor.
8. The pixel driving circuit according to claim 7, characterized in that, It also includes a second initialization unit, which, in response to a fourth scan signal, initializes the first and second terminals of the driving transistor with a second initialization voltage.
9. The pixel driving circuit according to claim 8, characterized in that, The second initialization unit includes a sixth transistor, the control terminal of which is electrically connected to the fourth scan signal line, the first terminal of which is electrically connected to the second initialization voltage signal line, and the second terminal of which is electrically connected to the first terminal of the driving transistor.
10. The pixel driving circuit according to claim 9, characterized in that, The light-emitting control unit includes a seventh transistor and an eighth transistor, wherein... The control terminal of the seventh transistor is electrically connected to the light emission control signal line, the first terminal of the seventh transistor is electrically connected to the first power supply voltage signal line, and the second terminal of the seventh transistor is electrically connected to the first terminal of the driving transistor. The control terminal of the eighth transistor is electrically connected to the light-emitting control signal line, the first terminal of the eighth transistor is electrically connected to the second terminal of the driving transistor, and the second terminal of the eighth transistor is electrically connected to the first terminal of the light-emitting element. The second end of the light-emitting element is electrically connected to the second power supply voltage signal line.
11. A driving method for a pixel driving circuit, characterized in that, The method for driving a pixel driving circuit as described in any one of claims 2, 4 to 10 includes the following steps: In the first initialization phase, the first scan signal and the third scan signal are at the working level, and the potential of the first node and the first terminal of the potential stabilization unit are initialized with the first initialization voltage; During the data writing and threshold compensation phases, the second scan signal is at the working level, writing the data voltage and the threshold voltage of the driving transistor to the first node and storing them in the first capacitor; During the potential stabilization phase, the third scanning signal is at the working level to stabilize the potential of the first node; During the light-emitting phase, the light-emitting control signal is at the operating level, driving the light-emitting element to emit light.
12. A driving method for a pixel driving circuit, characterized in that, The method for driving the pixel driving circuit according to any one of claims 3 to 10 includes the following steps: In the first initialization phase, the first scan signal is at the working level, and the potential of the first node is initialized with the first initialization voltage; During the data writing and threshold compensation phases, the second scan signal is at the working level, writing the data voltage and the threshold voltage of the driving transistor to the first node and storing them in the first capacitor; During the potential stabilization phase, the third scanning signal is at the working level to stabilize the potential of the first node; During the light-emitting phase, the light-emitting control signal is at the operating level, driving the light-emitting element to emit light.
13. A display panel, characterized in that, Includes the pixel driving circuit as described in any one of claims 1 to 10.
14. A display device, characterized in that, Includes the pixel driving circuit as described in any one of claims 1 to 10.