Display device and pixel driving circuit

Abstract

The embodiment of the invention belongs to the display circuit technology, and provides a display device and a pixel driving circuit, the display device comprises a display panel and the pixel driving circuit, the circuit comprises a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, the first end of the first capacitor receives a periodic first control signal, and the second end is connected with the first end of the second switch tube; the second end of the second switch tube is connected with the first end of the third switch tube and the control end of the fourth switch tube. The second end of the third switching tube receives a high-level signal or a low-level signal; the first end of the fourth switch tube receives a PAMD signal, and the second end of the fourth switch tube is connected with the control end of the fifth switch tube; the first end of the second capacitor receives a periodic second control signal, and the second end is connected with the control end of the fifth switch tube; the second end of the sixth switch tube is connected with the first end of a fifth switch tube; and the second end of the fifth switch tube is connected with the LED. According to the invention, the number of switching tubes is reduced, and the occupied pixel area is reduced.

Description

Technical Field

[0001] The present application relates to display circuit technology, and more specifically, to a display device and a pixel driving circuit. Background Art

[0002] Mini-LED and Micro-LED are widely used in display products due to their advantages such as high brightness and excellent picture quality.

[0003] In the prior art, a driving circuit combining PAM (Pulse Amplitude Modulation) and PWM (Pulse Width Modulation) is usually used to drive Mini-LED and Micro-LED high grayscale displays. However, the structure of the driving circuit is relatively complex, resulting in a larger pixel area occupied. Summary of the invention

[0004] The exemplary embodiments of the present application provide a display device and a pixel driving circuit to solve the problem that the prior art uses a driving circuit combining PAM and PWM to drive LEDs, which occupies a large pixel area.

[0005] In a first aspect, an embodiment of the present application provides a display device, including: a display panel and a pixel driving circuit;

[0006] The display panel includes a plurality of pixels, each pixel including at least one LED;

[0007] The pixel driving circuit includes:

[0008] A first switch tube, the control end of which is used to receive a periodic input light-emitting signal, the first end of which is used to receive a high-level signal, and the second end of which is connected to the control end of the second switch tube;

[0009] A first capacitor, a first end of which is used to receive a periodic first control signal, and a second end of which is connected to a first end of a second switch tube;

[0010] The second end of the second switch tube is respectively connected to the first end of the third switch tube and the control end of the fourth switch tube;

[0011] The control end of the third switch tube is used to receive an input light-emitting signal, and the second end is used to receive a high-level signal or a low-level signal;

[0012] The first end of the fourth switch tube is used to receive the PAMD signal, and the second end is connected to the control end of the fifth switch tube;

[0013] A second capacitor, a first end of which is used to receive a periodic second control signal, and a second end of which is connected to the control end of the fifth switch tube;

[0014] A sixth switch tube, whose control end is used to receive an input light-emitting signal, whose first end is used to receive a power supply voltage signal, and whose second end is connected to the first end of the fifth switch tube;

[0015] The second end of the fifth switch tube is connected to the LED;

[0016] Among them, the cycles of the input luminous signal, the first control signal and the second control signal are the same, and the input luminous signal has a high and low level conversion in each cycle. When the level of the input luminous signal is the level for controlling the conduction of the first switch tube, the first control signal and the second control signal change linearly.

[0017] In a second aspect, an embodiment of the present application provides a display device, including: a display panel and a pixel driving circuit;

[0018] The pixel driving circuit is configured as:

[0019] When the level of the input light-emitting signal is the level for controlling the first switch tube to be turned on, the input light-emitting signal is received through the control end of the first switch tube, the first end receives a high-level signal, and the first switch tube is turned on to set the voltage of the control end of the second switch tube to the voltage corresponding to the high-level signal;

[0020] A linearly changing first control signal is received through the first end of the first capacitor, so that the voltage of the first end of the second switch tube at the second end of the first capacitor changes, the on-off of the second switch tube is controlled, and when the second switch tube is turned on, the on-off of the fourth switch tube is controlled;

[0021] The input light-emitting signal is received through the control end of the third switch tube, and the second end receives a high-level signal or a low-level signal, and the third switch tube is turned on, so that when the second switch tube is turned off, the on and off of the fourth switch tube is controlled;

[0022] The input light emitting signal is received through the control end of the sixth switch tube, the first end receives the power supply voltage signal, and the sixth switch tube is turned on to set the voltage of the first end of the fifth switch tube to the voltage corresponding to the power supply voltage signal;

[0023] The PAMD signal is received through the first end of the fourth switch tube, so that when the fourth switch tube is turned on, the voltage at the control end of the fifth switch tube is set to PAMD, the fifth switch tube is turned on, and the LED emits light;

[0024] The first end of the second capacitor receives a linearly changing second control signal, so that when the fourth switch tube is turned off, the voltage of the fifth switch tube control end at the second end of the second capacitor changes, and the fifth switch tube is controlled to be turned off, and the LED stops emitting light;

[0025] Among them, the input luminous signal, the first control signal and the second control signal are periodic signals with the same period. The input luminous signal has a high and low level conversion within the period. When the level of the input luminous signal is the level for controlling the conduction of the first switch tube, the first control signal and the second control signal change linearly.

[0026] In a third aspect, an embodiment of the present application provides a pixel driving circuit, including:

[0027] A first switch tube, the control end of which is used to receive a periodic input light-emitting signal, the first end of which is used to receive a high-level signal, and the second end of which is connected to the control end of the second switch tube;

[0028] A first capacitor, a first end of which is used to receive a periodic first control signal, and a second end of which is connected to a first end of a second switch tube;

[0029] The second end of the second switch tube is respectively connected to the first end of the third switch tube and the control end of the fourth switch tube;

[0030] The control end of the third switch tube is used to receive an input light-emitting signal, and the second end is used to receive a high-level signal or a low-level signal;

[0031] The first end of the fourth switch tube is used to receive the PAMD signal, and the second end is connected to the control end of the fifth switch tube;

[0032] A second capacitor, a first end of which is used to receive a periodic second control signal, and a second end of which is connected to the control end of the fifth switch tube;

[0033] A sixth switch tube, whose control end is used to receive an input light-emitting signal, whose first end is used to receive a power supply voltage signal, and whose second end is connected to the first end of the fifth switch tube;

[0034] The second end of the fifth switch tube is connected to the LED;

[0035] Among them, the cycles of the input luminous signal, the first control signal and the second control signal are the same, and the input luminous signal has a high and low level conversion in each cycle. When the level of the input luminous signal is the level for controlling the conduction of the first switch tube, the first control signal and the second control signal change linearly.

[0036] The present application provides a display device and a pixel driving circuit. In the pixel driving circuit, when the level of the input light-emitting signal is the level for controlling the first switch tube to be turned on, the first switch tube, the third switch tube and the sixth switch tube are all turned on based on the level of the current input light-emitting signal. Based on the first switch tube being turned on, the voltage of the control end of the second switch tube is set to VGH. If the second end of the third switch tube receives a low-level signal, the second switch tube can be controlled to be turned off first and then turned on based on the linearly changing first control signal and the first capacitor. When the second switch tube is in the off state, the fourth switch tube and the fifth switch tube are turned on based on the third switch tube, and the LED emits light. After the second switch tube is in the on state, the fourth switch tube is turned off, and based on the linearly changing second control signal and the second capacitor, the fifth switch tube is turned off, and the LED stops emitting light, thereby realizing the light emission control of the LED. If the second end of the third switch tube receives a high-level signal, the second switch tube can be controlled to be turned on first and then turned off based on the linearly changing first control signal and the first capacitor. When the second switch tube is in the on state, the fourth switch tube and the fifth switch tube are turned on, and the LED emits light. When the second switch tube is turned off, based on the third switch tube, the fourth switch tube is turned off, and based on the linearly changing second control signal and the second capacitor, the fifth switch tube is controlled to be turned off, and the LED stops emitting light, thereby realizing the light-emitting control of the LED. The present application controls the turning off of the fifth switch tube connected to the LED based on the second capacitor and the second control signal, replaces some of the switch tubes included in the pixel driving circuit in the prior art, reduces the number of switch tubes, and thus reduces the occupied pixel area. At the same time, the present application also allows the control end of the second switch tube to receive a high-level signal, and the first end to receive the first control signal, so that when the first switch tube, the second switch tube and the third switch tube are all turned on, the current of the conduction circuit is low, thereby reducing power consumption.

[0037] These and other aspects of the present application will become more apparent from the following description of the embodiment(s). BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the implementation methods in the embodiments of the present application or the related technologies, the following is a brief introduction to the drawings required for use in the embodiments or the related technology descriptions. Obviously, the drawings described below are some embodiments of the present application, and a person skilled in the art can also obtain other drawings based on these drawings.

[0039] Figure 1 A schematic diagram of a planar structure of a display device provided in an embodiment of the present application;

[0040] Figure 2 A structural diagram of a pixel driving circuit in the prior art;

[0041] Figure 3A schematic diagram of the structure of a display device provided in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of the structure of a pixel driving circuit provided in an embodiment of the present application;

[0043] Figure 5 A timing diagram of the related control signal levels corresponding to the P-type thin film transistor when the second end of the third switch tube T3 receives the low level signal VGL provided in an embodiment of the present application;

[0044] Figure 6 A schematic diagram of the structure of a pixel driving circuit corresponding to a P-type thin film transistor when the second end of the third switch tube T3 receives a low level signal VGL during a reset phase provided by an embodiment of the present application;

[0045] Figure 7 A schematic diagram of the structure of a pixel driving circuit corresponding to a P-type thin film transistor when the second end of the third switch tube T3 receives a low level signal VGL during a data input phase provided by an embodiment of the present application;

[0046] Figure 8 A schematic diagram of a pixel driving circuit corresponding to a P-type thin film transistor when the second end of the third switch tube T3 receives a low-level signal VGL at an early stage of a comparative light-emitting phase provided by an embodiment of the present application;

[0047] Fig. 9 A structural schematic diagram of a pixel driving circuit corresponding to a P-type thin film transistor when the second end of the third switch tube T3 receives a low-level signal VGL in a late light-emitting stage provided by an embodiment of the present application;

[0048] Fig.10 A schematic structural diagram of a pixel driving circuit corresponding to an N-type thin film transistor provided in an embodiment of the present application;

[0049] Fig.11 A timing diagram of the related control signal levels corresponding to the N-type thin film transistor when the second end of the third switch tube T3 receives the low level signal VGL provided in an embodiment of the present application;

[0050] Fig.12 A flow chart of a control method for a pixel driving circuit provided in an embodiment of the present application;

[0051] Fig.13 A schematic diagram of a control device for a pixel driving circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0053] Based on the exemplary embodiments described in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the claims attached to this application. In addition, although the disclosure in this application is introduced according to one or several exemplary examples, it should be understood that each aspect of the disclosure can also constitute a complete implementation method separately.

[0054] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0055] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise indicated. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, for example, they can be implemented according to orders other than those given in the diagrams or descriptions of the embodiments of this application.

[0056] In addition, the terms "including" and "having" and any variations thereof are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to those components expressly listed but may include other components not expressly listed or inherent to such products or devices.

[0057] Figure 1 A schematic diagram of a planar structure of a display device provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the display device may include a pixel array unit 100, a control circuit 200, a data driving circuit 300 and a scan driving circuit 400, wherein the data driving circuit 300 may be a data driver and the scan driving circuit 400 may be a gate driver.

[0058] The pixel array unit 100 may include a plurality of scan lines SL and a plurality of data lines DL disposed on a substrate, and a plurality of pixels P disposed in a plurality of pixel areas defined by crossing portions of the plurality of scan lines SL and the plurality of data lines DL, respectively.

[0059] Each of the plurality of pixels P may include a pixel unit that displays an image based on a scan signal provided by an adjacent scan line SL and a data signal provided by an adjacent data line DL. Specifically, the pixel unit may include at least one thin film transistor and at least one capacitor, and the pixel unit may be a liquid crystal unit that displays an image by driving the liquid crystal according to an electric field based on a data signal, or may be a self-luminous unit that displays an image based on self-luminescence of a data signal. In this case, the self-luminous unit may include a plasma discharge element, a quantum dot light-emitting element, an organic light-emitting element, an inorganic light-emitting element, or a micro-light-emitting diode. It should be noted that the pixel driving circuit provided in the embodiment of the present application belongs to the pixel unit.

[0060] The control circuit 200 may generate pixel data corresponding to each of the plurality of pixels P based on the image signal. The control circuit 200 may generate a data control signal based on the timing synchronization signal to provide the data control signal to the data driving circuit 300. According to an example, the control circuit 200 may generate a start signal and a scanning control signal of a plurality of scanning clock signals based on the timing synchronization signal to provide the scanning control signal to the scanning driving circuit 400. The control circuit 200 may additionally generate a plurality of carry clock signals according to the driving mode of the scanning driving circuit 400 to provide the plurality of carry clock signals to the scanning driving circuit 400.

[0061] The data driving circuit 300 may be connected to a plurality of data lines DL provided in the pixel array unit 100. The data driving circuit 300 may receive pixel data and a data control signal provided from the control circuit 200, and may receive a plurality of reference gamma voltages provided from the power supply circuit. The data driving circuit 300 may convert the pixel data into a pixel-based analog data signal using the data control signal and the plurality of reference gamma voltages, and provide the analog data signal to the corresponding data line DL. The analog data signal is the PWMD signal provided in the embodiment of the present application.

[0062] The scan driving circuit 400 may be connected to a plurality of scan lines SL provided in the pixel array unit 100. Specifically, the scan driving circuit 400 may generate a scan signal according to a predetermined sequence determined based on a scan control signal provided by the control circuit 200, and provide the scan signal to the corresponding scan line SL. The scan signal is the row scan signal SN provided in the embodiment of the present application.

[0063] In some embodiments, the scan driving circuit 400 may be integrated on one edge or two edges of the substrate according to the manufacturing process of the thin film transistor, and then connected to the plurality of scan lines SL in a one-to-one correspondence. For example, the scan driving circuit 400 may be provided in an integrated circuit, may be packaged in a substrate or a flexible circuit film, and may be connected to the plurality of scan lines SL in a one-to-one correspondence.

[0064] Mini-LED and Micro-LED have a higher penetration rate in display products due to their high brightness and excellent image quality. However, the current mainstream TFT (Thin Film Transistor) driving method is to use LTPS (Low Temperature Poly-Silicon) TFT or oxide TFT to drive.

[0065] LTPS TFT has higher electron mobility and better stability, but its cost is higher. In addition, LTPS TFT is limited by the problem of uniformity and cannot be made into large-size single-board, that is, larger than 20 inches.

[0066] Oxide TFT is an amorphous semiconductor device with good uniformity and can be made into large size. However, due to the very low leakage current of the device, it can be used as a low-frequency drive product to achieve ultra-low power consumption. However, due to the poor stability of the device and the low electron mobility, it is not suitable for driving LED chips. It can be used as a switching device, but the cost is also high.

[0067] Traditional a-Si TFT (amorphous silicon thin-film transistor) is a method with a relatively mature industry chain, high yield and low cost. However, due to its low electron mobility, which is usually less than 1, and poor stability, it is generally considered to be unsuitable for driving Micro-LEDs.

[0068] The existing technology can use a driving method combining PAM and PWM for Mini-LED and Micro-LED high grayscale display. The structure diagram of a pixel driving circuit in the existing technology can be referred to Figure 2 As shown in the figure, since the driving circuit includes 11 switch tubes, which is a large number, the pixel area is larger. At the same time, in the comparative light-emitting stage, Figure 2 When the switch tubes T2, T3 and T5 are all turned on, the voltages VGH and VGL form a connection channel, causing the power consumption of the driving circuit to increase.

[0069] The embodiment of the present application provides a display device, the pixel driving circuit of the display device introduces a periodic second control signal and a second capacitor. When the level of the input light-emitting signal is the level for controlling the first switch tube to be turned on, based on the second capacitor, the fifth switch tube connected to the LED can be turned off by changing the second control signal, thereby controlling the LED to stop emitting light. By introducing the second control signal and the second capacitor, the present application replaces some of the switch tubes included in the pixel driving circuit of the prior art, reduces the number of switch tubes, and effectively reduces the occupied pixel area.

[0070] Figure 3 A schematic diagram of a display device provided in an embodiment of the present application is shown in FIG. Figure 3 As shown, the display device includes: a display panel 10 and a pixel driving circuit 20;

[0071] The display panel 10 includes a plurality of pixels, each pixel including at least one LED;

[0072] The pixel driving circuit 20 comprises:

[0073] The first switch tube T1, the control end is used to receive the periodic input light emitting signal EM, the first end is used to receive the high level signal VGH, and the second end is connected to the control end of the second switch tube T2;

[0074] A first capacitor C1, a first end of which is used to receive a periodic first control signal Sweep1, and a second end of which is connected to a first end of a second switch tube T2;

[0075] The second end of the second switch tube T2 is respectively connected to the first end of the third switch tube T3 and the control end of the fourth switch tube T4;

[0076] The control end of the third switch tube T3 is used to receive the input light emitting signal EM, and the second end is used to receive the high level signal VGH or the low level signal VGL;

[0077] A first end of the fourth switch tube T4 is used to receive a PAMD signal, and a second end is connected to a control end of the fifth switch tube T5;

[0078] A second capacitor C2, a first end of which is used to receive a periodic second control signal Sweep2, and a second end of which is connected to a control end of the fifth switch tube T5;

[0079] The sixth switch tube T6 has a control end for receiving the input light emitting signal EM, a first end for receiving the power supply voltage signal VDD, and a second end connected to the first end of the fifth switch tube T5;

[0080] The second end of the fifth switch tube T5 is connected to the LED;

[0081] Among them, the cycles of the input light-emitting signal EM, the first control signal Sweep1 and the second control signal Sweep2 are the same, and the input light-emitting signal EM has a high-low level conversion in each cycle. When the level of the input light-emitting signal EM is the level for controlling the conduction of the first switch tube, the first control signal Sweep1 and the second control signal Sweep2 change linearly.

[0082] In some embodiments, any of the first to sixth switch tubes T1 to T6 may be a P-type thin film transistor or an N-type thin film transistor, and the conduction conditions of the two are somewhat different. For a P-type thin film transistor, when the voltage difference between the gate and the source Vgs is less than 0, the transistor is in the conduction state. For an N-type thin film transistor, when the voltage difference between the gate and the source Vgs is greater than 0, the transistor is in the conduction state.

[0083] The switching tube may include a gate, a source and a drain. The control end of the above-mentioned switching tube is the gate, the first end may be the source, the second end is the drain, or the first end is the drain and the second end is the source. At this time, it is only necessary to satisfy the conduction and shutdown of the switching tube, and this application does not impose any restrictions on this.

[0084] The first switch tube T1 is used to set the voltage at the control terminal of the second switch tube T2 to VGH when the first switch tube T1 is turned on.

[0085] The first capacitor C1 is used to change the voltage at the first end of the second switch tube T2 when the first control signal Sweep1 changes, so as to control the on and off of the second switch tube T2.

[0086] The second switch tube T2 is used to control the voltage at the control end of the fourth switch tube T4 when the second switch tube T2 is turned on, so as to control the on and off of the fourth switch tube T4.

[0087] If the second switch tube T2 is turned off, the third switch tube T3 is used to set the voltage of the control terminal of the fourth switch tube T4 to VGH or VGL when the third switch tube T3 is turned on, so as to control the on and off of the fourth switch tube T4.

[0088] The fourth switch tube T4 is used to set the voltage at the control end of the fifth switch tube T5 to PAMD when the fourth switch tube T4 is turned on, so as to control the fifth switch tube T5 to be turned on and the LED to emit light.

[0089] The sixth switch tube T6 is used for setting the voltage at the first end of the fifth switch tube T5 to VDD when the sixth switch tube T6 is turned on.

[0090] The second capacitor C2 is used to change the voltage at the control end of the fifth switch tube T5 based on the change of the second control signal Sweep2 when the fourth switch tube T4 is turned off, so as to control the fifth switch tube T5 to turn off and the LED stops emitting light.

[0091] The embodiment of the present application provides a display device, comprising a display panel 10 and a pixel driving circuit 20, wherein in the pixel driving circuit 20, when the level of the input light emitting signal EM is the level for controlling the first switch tube T1 to be turned on, based on the level of the current input light emitting signal EM, the first switch tube T1, the third switch tube T3 and the sixth switch tube T6 are all turned on. Since the first switch tube T1 is turned on, the voltage at the control end of the second switch tube T2 is set to VGH. If the second end of the third switch tube T3 receives a low-level signal VGL, the second switch tube T2 can be controlled to be turned off first and then turned on based on the linearly changing first control signal Sweep1 and the first capacitor C1. When the second switch tube T2 is in the off state, based on the third switch tube T3, the fourth switch tube T4 and the fifth switch tube T5 are further turned on, and the LED starts to emit light. When the second switch tube T2 is turned on, the fourth switch tube T4 is turned off, and based on the linearly changing second control signal Sweep2 and the second capacitor C2, the fifth switch tube T5 is controlled to be turned off, and the LED stops emitting light. If the second end of the third switch tube T3 receives a high-level signal VGH, based on the linearly changing first control signal Sweep1 and the first capacitor C1, the second switch tube T2 is controlled to be turned on first and then turned off. When the second switch tube T2 is in the on state, the fourth switch tube T4 and the fifth switch tube T5 can be controlled to be turned on, and the LED emits light. When the second switch tube T2 is turned off, based on the third switch tube T3, the fourth switch tube T4 is turned off. Based on the linearly changing second control signal Sweep2 and the second capacitor C2, the fifth switch tube T5 is controlled to be turned off, and the LED stops emitting light. The pixel driving circuit 20 of the present application is based on the second capacitor C2, and the fifth switch tube T5 connected to the LED can be controlled to be turned off by the change of the second control signal Sweep2. By introducing the second control signal Sweep2 and the second capacitor C2, part of the switch tubes included in the pixel driving circuit in the prior art are replaced, the number of switch tubes is reduced, and thus the occupied pixel area is reduced. At the same time, the present application also enables the control end of the second switch tube T2 to receive the high level signal VGH, and the first end to receive the first control signal Sweep1, so that when the first switch tube T1, the second switch tube T2 and the third switch tube T3 are all turned on, the current of the conduction circuit is low, thereby reducing power consumption.

[0092] Figure 4 This is a schematic diagram of a pixel driving circuit provided in an embodiment of the present application. The pixel driving circuit 20 can be applied to a display device. In one or more embodiments of the present application, the pixel driving circuit 20 further includes:

[0093] The ninth switch tube T9, the control end is used to receive the periodic reset signal Reset, the first end is used to receive the reference voltage signal Ref, and the second end is connected to the first end of the second switch tube T2; the reset signal Reset has the same period as the input light-emitting signal EM, and there is a high and low level conversion in each period.

[0094] The ninth switch tube T9 is used to set the voltage of the first end of the second switch tube T2 to Ref when it is turned on. The voltage of the first end of the second switch tube T2 is reset by the ninth switch tube T9 to clear the remaining charge at the first end of the second switch tube T2 to prevent the remaining charge from affecting the on and off of the second switch tube T2.

[0095] In some embodiments, the pixel driving circuit 20 also includes a seventh switch tube T7, a control end of which is used to receive a periodic row scan signal SN, a first end of which is used to receive a PWMD signal, and a second end of which is connected to the control end of the second switch tube T2; the row scan signal SN has the same period as the input light-emitting signal EM, and there is a high and low level conversion in each period.

[0096] In some embodiments, the row scan signal SN received by the control end of the seventh switch tube T7 is a scan signal transmitted by the scan driving circuit 400 through the scan line SL in the display device, and the PWMD signal received by the first end is an analog data signal transmitted by the data driving circuit 300 through the data line DL in the display device.

[0097] The seventh switch tube T7 is used to set the voltage at the control end of the second switch tube T2 to PWMD when the seventh switch tube T7 is turned on.

[0098] In some embodiments, the pixel driving circuit 20 also includes an eighth switch tube T8, whose control end is used to receive a row scanning signal SN, whose first end is connected to the second end of the seventh switch tube T7, and whose second end is connected to the first end of the third switch tube T3, for threshold compensation of the second switch tube T2.

[0099] The eighth switch tube T8 is used to connect the control end and the second end of the second switch tube T2 to form a diode structure when it is turned on, so as to perform threshold compensation on the second switch tube T2, which is beneficial to eliminate the influence of the offset of the threshold voltage Vth of the second switch tube T2 and improve the display effect.

[0100] In some embodiments, the pixel driving circuit 20 may further include: a third capacitor C3, a first end of which is used to receive the power supply voltage signal VDD, and a second end of which is connected to the control end of the fourth switch tube T4, and is used to stabilize the voltage of the control end of the fourth switch tube T4, that is, point B, to improve the stability of the pixel driving circuit 20. Point B can represent the control end of the fourth switch tube T4, the second end of the second switch tube T2, and the first end of the third switch tube T3.

[0101] It should also be noted that the pixel driving circuit 20 includes nine switching tubes, and the switching tubes among the first switching tube T1, the second switching tube T2, the third switching tube T3, the fourth switching tube T4, the fifth switching tube T5, the sixth switching tube T6, the seventh switching tube T7, the eighth switching tube T8, and the ninth switching tube T9 are P-type thin film transistors, or N-type thin film transistors. The present application does not limit the type of the switching tube.

[0102] In summary, the voltage at the first end of the second switch tube T2 is reset by the ninth switch tube T9 to eliminate the influence of the residual charge in the previous cycle. The threshold voltage Vth of the second switch tube T2 is compensated by the eighth switch tube T8 to eliminate the influence of the drift of the threshold voltage Vth of the second switch tube T2, which is beneficial to improve the display effect.

[0103] Based on the above embodiment, an embodiment is provided below to describe the driving process of the pixel driving circuit 20 in the display device.

[0104] An embodiment of the present application provides a display device, including a display panel 10 and a pixel driving circuit 20 .

[0105] The pixel driving circuit 20 is configured as follows:

[0106] When the level of the input light-emitting signal EM is the level for controlling the first switch tube T1 to be turned on, the input light-emitting signal EM is received through the control end of the first switch tube T1, and the first end receives the high-level signal VGH, and the first switch tube T1 is turned on to set the voltage at the control end of the second switch tube T2 to the voltage corresponding to the high-level signal VGH;

[0107] A linearly changing first control signal Sweep1 is received through the first end of the first capacitor C1, so that the voltage of the first end of the second switch tube T2 at the second end of the first capacitor C1 changes, and the on-off of the second switch tube T2 is controlled, and when the second switch tube T2 is turned on, the on-off of the fourth switch tube T4 is controlled;

[0108] The third switch tube T3 receives the input light emitting signal EM through the control end thereof and receives the high level signal VGH or the low level signal VGL through the second end thereof, and the third switch tube T3 is turned on, so that when the second switch tube T2 is turned off, the fourth switch tube T4 is controlled to be turned on and off;

[0109] The input light emitting signal EM is received through the control end of the sixth switch tube T6, and the first end receives the power supply voltage signal VDD, and the sixth switch tube T6 is turned on to set the voltage of the first end of the fifth switch tube T5 to the voltage corresponding to the power supply voltage signal VDD;

[0110] The PAMD signal is received through the first end of the fourth switch tube T4, so that when the fourth switch tube T4 is turned on, the voltage at the control end of the fifth switch tube T5 is set to PAMD, the fifth switch tube T5 is turned on, and the LED emits light;

[0111] The first end of the second capacitor C2 receives a linearly changing second control signal Sweep2, so that when the fourth switch tube T4 is turned off, the voltage at the control end of the fifth switch tube T5 at the second end of the second capacitor C2 changes, and the fifth switch tube T5 is controlled to be turned off, and the LED stops emitting light;

[0112] Among them, the input luminous signal EM, the first control signal Sweep1 and the second control signal Sweep2 are periodic signals with the same period. The input luminous signal EM has a high-low level conversion within the period. When the level of the input luminous signal EM is the level for controlling the conduction of the first switch tube T1, the first control signal Sweep1 and the second control signal Sweep2 change linearly.

[0113] In some embodiments, the cycle of the input light-emitting signal EM, the first control signal Sweep1 and the second control signal Sweep2 includes at least: a reset stage, a data input stage and a comparison light-emitting stage, the reset stage is located before the data input stage, and the data input stage is located before the comparison light-emitting stage. Among them, when the level of the input light-emitting signal EM is the level that controls the conduction of the first switch tube T1, it corresponds to the comparison light-emitting stage. The reset stage is the process of initializing the pixel driving circuit 20, and the data input stage refers to the process of the pixel driving circuit 20 receiving the PWMD signal. The LED driving process corresponding to the reset stage and the data input stage can refer to other embodiments, which will not be repeated here.

[0114] The structure of the pixel driving circuit 20 can be referred to Figure 4 In some embodiments, if the above switch tubes are all P-type thin film transistors, since driving the LED may include two processes of controlling the LED to emit light and stopping the light emission, the fifth switch tube T5 needs to be controlled to be turned on first and then turned off, so the second control signal Sweep2 needs to be gradually increased, and the fourth switch tube T4 needs to be turned on first and then turned off.

[0115] In one implementation scenario, if the above-mentioned switch tubes are all P-type thin film transistors, and the second end of the third switch tube T3 receives a high-level signal VGH, in the comparative light-emitting stage, the second switch tube T2 needs to be turned on first and then turned off, so the first control signal Sweep1 needs to be gradually reduced. When the first control signal Sweep1 decreases within a certain range, the voltage at point A is less than the voltage at point S, and the second switch tube T2 remains in the on state. When the first control signal Sweep1 continues to decrease, causing the voltage at point A to be greater than the voltage at point S, the second switch tube T2 is turned off at this time, so the driving of the LED can also be achieved.

[0116] When the above switch tubes are all P-type thin film transistors and the second end of the third switch tube T3 receives the high level signal VGH, the pixel driving process corresponding to the pixel driving circuit 20 in the comparative light-emitting stage is specifically as follows:

[0117] Based on the conduction condition of the P-type thin film transistor, in the comparative light emitting stage, the input light emitting signal EM is at a low level, the first control signal Sweep1 decreases linearly, and the second control signal Sweep2 increases linearly.

[0118] Since the input light-emitting signal EM is at a low level, for the first switch tube T1, since EM<VGH, the first switch tube T1 is turned on, and the voltage at point A, i.e., the control end of the second switch tube T2, is set to VGH. At this time, the voltage at point S, i.e., the first end of the second switch tube T2, is PWMD+Vth, VGH<PWMD+Vth, and the second switch tube T2 is turned on.

[0119] As the first control signal Sweep1 gradually decreases, based on the effect of the first capacitor C1, the voltage at point S also decreases. When the voltage VGH at point A is still lower than the voltage at point S, the second switch tube T2 remains on and sets point B to a low potential. Since the voltage at point B, i.e., the control terminal of the fourth switch tube T4, is lower than the voltage PAMD at the first terminal, the fourth switch tube T4 is turned on. Based on the fourth switch tube T4, the voltage at point C, i.e., the control terminal of the fifth switch tube T5, is set to PAMD.

[0120] Since the control end of the sixth switch tube T6 receives the low-level input light-emitting signal EM, and the first end receives the power supply voltage signal VDD, EM<VDD, the sixth switch tube T6 is turned on, and the voltage of the first end of the fifth switch tube T5 is set to VDD. For the fifth switch tube T5, PAMD<VDD, so the fifth switch tube T5 is turned on, and the LED emits light.

[0121] As the first control signal Sweep1 continues to decrease, based on the effect of the first capacitor C1, the voltage at point S also continues to decrease. When the voltage at point A is greater than the voltage at point S, the second switch tube T2 is turned off.

[0122] Since the control end of the third switch tube T3 receives the low-level input light-emitting signal EM and the second end receives the low-level signal VGL, EM<VGL, the third switch tube T3 is turned on. After the second switch tube T2 is turned off, based on the third switch tube T3, the voltage at point B is set to VGH, VGH>PAMD, causing the fourth switch tube T4 to be turned off.

[0123] As the second control signal Sweep2 gradually increases, based on the effect of the second capacitor C2, the voltage at point C also gradually increases. When the voltage at point C is greater than VDD, the fifth switch tube T5 is turned off, and the LED stops emitting light.

[0124] In another implementation scenario, if the above-mentioned switch tubes are all P-type thin-film transistors, and the second end of the third switch tube T3 receives a low-level signal VGL, then in the comparative light-emitting stage, the second switch tube T2 needs to be turned off first and then turned on, so the first control signal Sweep1 needs to be gradually increased. When the first control signal Sweep1 increases within a certain range, since the voltage at point A is still greater than the voltage at point S, the second switch tube T2 can remain in the off state. When the first control signal Sweep1 exceeds the range, the voltage at point A is less than the voltage at point S. At this time, the second switch tube T2 is turned on, so the driving of the LED can be realized. Among them, point A can represent the second end of the first switch tube T1, and can also represent the control end of the second switch tube T2. Point S can represent the first end of the second switch tube T2.

[0125] In the case where the above-mentioned switch tubes are all P-type thin film transistors, and the second end of the third switch tube T3 receives the low level signal VGL, based on the conduction principle of the P-type thin film transistor, the level of controlling the conduction of the first switch tube T1 is low level, so that in the comparative light-emitting stage, the input light-emitting signal EM can be controlled to be low level, and the first control signal Sweep1 and the second control signal Sweep2 are synchronously linearly increased. The specific driving process can refer to other embodiments and the embodiment of the present application, the driving process of the second end of the third switch tube T3 receiving the high level signal VGH, and the present application will not repeat it here.

[0126] In some embodiments, the pixel driving circuit 20 further includes: a seventh switch tube T7;

[0127] The control end of the seventh switch tube T7 receives the periodic row scanning signal SN, and the first end receives the PWMD signal, so that when the seventh switch tube T7 is turned on, the voltage at the control end of the second switch tube T2 is set to PWMD;

[0128] The row scanning signal SN has the same period as the input light emitting signal EM, and has a high-low level transition in each period.

[0129] In some embodiments, the pixel driving circuit 20 further includes an eighth switch tube T8 ; the row scanning signal SN is received through the control terminal of the eighth switch tube T8 , so that when the eighth switch tube T8 is turned on, threshold compensation is performed on the second switch tube T2 .

[0130] In one implementation scenario, the cycle of the row scanning signal SN also includes at least: a reset phase, a data input phase and a comparison light emitting phase. The seventh switch tube T7 and the eighth switch tube T8 are mainly used in the data input phase, and the specific process can refer to other embodiments, and this application will not repeat them here.

[0131] In some embodiments, the pixel driving circuit 20 further includes: a ninth switch tube T9;

[0132] The control end of the ninth switch tube T9 receives a periodic reset signal Reset, and the first end receives a reference voltage signal Ref, so that when the ninth switch tube T9 is turned on, the voltage at the first end of the second switch tube T2 is set to the voltage corresponding to the reference voltage signal Ref; the reset signal Reset has the same period as the input light-emitting signal EM, and there is a high and low level conversion in each period.

[0133] In one implementation scenario, since the reset signal Reset has the same period as the input light-emitting signal EM, the period of the reset signal Reset also includes at least: a reset stage, a data input stage, and a comparison light-emitting stage. The ninth switch tube T9 is mainly used in the reset stage. The specific process can be referred to other embodiments, and this application will not repeat it here.

[0134] It should be noted that the above description is based on the example that the switch tube in the pixel driving circuit 20 is a P-type thin film transistor, and the switch tube in the pixel driving circuit 20 can also be an N-type thin film transistor. If the switch tube is an N-type thin film transistor, based on the conduction condition of the N-type thin film transistor, the levels of the input light-emitting signal EM, the first control signal Sweep1, and the second control signal Sweep2 in the comparison light-emitting stage are different from the levels of the corresponding signals of the above-mentioned P-type thin film transistor.

[0135] The embodiment of the present application provides a display device, comprising a display panel 10 and a pixel driving circuit 20. The pixel driving circuit 20 controls the fifth switch tube T5 to be turned off when the fourth switch tube T4 is turned off by introducing a second control signal Sweep2 and a second capacitor C2, so as to control the LED to stop emitting light, thereby reducing the number of switch tubes used, which is beneficial to reducing the occupied pixel area. At the same time, the control end of the second switch tube T2 of the present application receives a high-level signal VGH, and the first end receives a first control signal Sweep1, so that when the first switch tube T1, the second switch tube T2 and the third switch tube T3 are all turned on, the current of the conduction circuit is low, thereby effectively reducing power consumption.

[0136] The following provides a specific embodiment and describes the control process of the pixel driving circuit 20 in detail by taking the first switch tube T1 to the ninth switch tube T9 as P-type thin film transistors and the second end of the third switch tube T3 receiving the low level signal VGL as an example.

[0137] Figure 5A timing diagram of the relevant control signal level corresponding to the P-type thin film transistor when the second end of the third switch tube T3 receives a low level signal VGL provided in an embodiment of the present application. In some embodiments, the driving process of the LED may include a reset stage, a data input stage, and a comparison light-emitting stage. In the above multiple stages, the pixel driving circuit 20 can be controlled by the control module. The specific driving process of the pixel driving circuit 20 is as follows:

[0138] Reset phase:

[0139] Figure 6 A schematic diagram of the structure of the pixel driving circuit corresponding to the P-type thin film transistor when the second end of the third switch tube T3 receives the low level signal VGL during a reset phase provided by an embodiment of the present application. Figure 5 and Figure 6 It can be seen that in the reset stage, the reset signal Reset is at a low level. The control end of the ninth switch tube T9 receives the reset signal Reset, and the first end receives the reference voltage signal Ref, Reset<Ref, the ninth switch tube T9 is turned on, and the voltage of the first end of the second switch tube T2, that is, the voltage of point S, is set to Ref, and the original charge at point S is cleared to prevent the residual charge from affecting the on and off of the second switch tube T2. Among them, point S can represent the second end of the ninth switch tube T9 and the first end of the second switch tube T2.

[0140] In the reset phase, since the row scanning signal SN is at a high level, for the seventh switch tube T7, SN>PWMD, so the seventh switch tube T7 is turned off. Since the seventh switch tube T7 is turned off, there is no voltage at the first end of the eighth switch tube T8, so the eighth switch tube T8 is turned off.

[0141] In the reset stage, since the input light-emitting signal EM is at a high level, EM>VGH, the first switch tube T1 is turned off. Since EM>VGL, the third switch tube T3 is turned off. Since EM>VDD, the sixth switch tube T6 is turned off. Since the first switch tube T1 and the seventh switch tube T7 are both turned off, there is no voltage at the control end of the second switch tube T2, which in turn causes the second switch tube T2 to be turned off. Since the sixth switch tube T6 is turned off, there is no voltage at the first end of the fifth switch tube T5, the fifth switch tube T5 is turned off, and the LED does not emit light.

[0142] For the fourth switch tube T4 , if the residual charge in the previous cycle is not taken into account, at this time, there is no voltage at the control end of the fourth switch tube T4 , so the fourth switch tube T4 is turned off.

[0143] Since the first control signal Sweep1 and the second control signal Sweep2 are at a low level and remain unchanged during the reset phase, based on the basic characteristics of capacitors, the circuit where the first capacitor C1 and the circuit where the second capacitor C2 are located can be regarded as open circuits.

[0144] Data entry phase:

[0145] Figure 7 A schematic diagram of the structure of the pixel driving circuit corresponding to the P-type thin film transistor when the second end of the third switch tube T3 receives the low level signal VGL during a data input phase provided by an embodiment of the present application. Figure 7 and Figure 5 As shown, in the data input stage, the reset signal Reset is converted to a high level, Reset>Ref, and the ninth switch tube T9 is turned off.

[0146] The input light-emitting signal EM is at a high level, EM>VGH, and the first switch tube T1 is still in the off state. EM>VGL, and the third switch tube T3 is still in the off state. EM>VDD, so the sixth switch tube T6 is still in the off state, which in turn causes the fourth switch tube T4 and the fifth switch tube T5 to still be in the off state, and the LED does not emit light.

[0147] In the data input stage, since the first control signal Sweep1 and the second control signal Sweep2 are still at low level and remain unchanged, based on the basic characteristics of capacitors, the circuit where the first capacitor C1 and the circuit where the second capacitor C2 are located can be regarded as open circuits.

[0148] In the data input stage, the row scan signal SN is converted to a low level. The current SN is less than PWMD, so the seventh switch tube T7 is turned on, and the voltage at point A is set to PWMD, that is, the voltage at the first end of the eighth switch tube T8 is PWMD. The control end of the eighth switch tube T8 also receives the row scan signal SN, so the eighth switch tube T8 is turned on. At the same time, since the current voltage at point S is Ref, PWMD is less than Ref, causing the second switch tube T2 to be turned on. Among them, the PWMD signal is a voltage value that changes according to the brightness of the LED. Among them, point A can also represent the second end of the seventh switch tube T7 and the first end of the eighth switch tube T8.

[0149] Since the eighth switch tube T8 is turned on, the control end and the second end of the second switch tube T2 are connected, that is, the AB point is connected to form a diode (diode) structure, so the voltage at point B becomes PWMD, and the voltage at point S becomes PWMD+Vth, so as to perform threshold compensation on the second switch tube T2. Among them, Vth is the threshold voltage of the second switch tube T2. Point B can represent the second end of the second switch tube T2, the first end of the third switch tube T3, the control end of the fourth switch tube T4, and the second end of the eighth switch tube T8.

[0150] After the voltage at point S becomes PWMD+Vth, since the voltage at point A is PWMD at this time, the second switch tube T2 is turned off, the threshold voltage Vth of the second switch tube T2 can be stored on the first capacitor C1, and the data input stage ends.

[0151] Compare the luminous phases:

[0152] The comparative light-emitting stage can be divided into two stages, namely, an early comparative light-emitting stage and a late comparative light-emitting stage, according to the on-off of the second switch tube T2.

[0153] Figure 8 This is a schematic diagram of the structure of the pixel driving circuit corresponding to the P-type thin film transistor when the second end of the third switch tube T3 receives the low level signal VGL in the early stage of the comparative light-emitting phase provided by the embodiment of the present application. Figure 8 and Figure 5 As shown, at the beginning of the comparative light-emitting stage, the reset signal Reset is still at a high level, Reset>Ref, so the ninth switch tube T9 is still in the off state. The row scanning signal SN becomes a high level, at this time SN>PWMD, and the seventh switch tube T7 is turned off. Since the seventh switch tube T7 is turned off, there is no voltage at the first end of the eighth switch tube T8, so the eighth switch tube T8 is turned off.

[0154] At the beginning of the comparative light-emitting stage, the input light-emitting signal EM becomes a low level. Since EM<VGH at this time, the first switch tube T1 is turned on. The control end of the third switch tube T3 receives the input light-emitting signal EM, and the second end receives the low-level signal VGL. At this time, EM<VGL, and the third switch tube T3 is turned on. The control end of the sixth switch tube T4 also receives the input light-emitting signal EM, and the first end receives the power supply voltage signal VDD. At this time, EM<VDD, and the sixth switch tube T6 is turned on.

[0155] Since the first switch tube T1 is turned on, the voltage at point A is set to VGH. The current voltage at point S is PWMD+Vth, and the voltage difference between the control end and the first end of the second switch tube T2 is Vgs=VGH-PWMD-Vth, indicating that the threshold compensation of the second switch tube T2 has been completed. At the same time, since VGH>PWMD+Vth, the second switch tube T2 is in the off state at this time.

[0156] As the first control signal Sweep1 increases linearly, based on the first capacitor C1, the voltage at point S also gradually increases. When S<VGH+Vth, the second switch tube T2 remains in the off state. At this time, through the third switch tube T3, the voltage at point B is set to VGL, that is, the voltage at the control end of the fourth switch tube T4 is VGL. The first end of the fourth switch tube T4 receives a low-potential PAMD signal, VGL<PAMD, at this time the fourth switch tube T4 is turned on, and the voltage at point C is set to PAMD, that is, the voltage at the control end of the fifth switch tube T5 is PAMD. Among them, PAMD is a low-level signal, indicating the voltage value when the LED emits the highest brightness. Point C can represent the second end of the fourth switch tube T4, and can also represent the control end of the fifth switch tube T5.

[0157] Since the sixth switch tube T6 is turned on, the voltage at the first end of the fifth switch tube T5 is set to VDD. For the fifth switch tube T5, PAMD<VDD, and the fifth switch tube T5 is turned on at this time. The second end of the fifth switch tube T5 is connected to the anode of the LED, and the cathode of the LED is connected to the input light-emitting signal EM, and the LED can be controlled to be turned on at this time, and the LED starts to emit light.

[0158] Fig. 9 This is a schematic diagram of a pixel driving circuit corresponding to a P-type thin film transistor when the second end of the third switch tube T3 receives a low level signal VGL in a later period of a comparative light-emitting phase provided by an embodiment of the present application. Fig. 9 and Figure 5 As shown, in the later stage of the comparative light-emitting phase, the reset signal Reset is still at a high level, Reset>Ref, so the ninth switch tube T9 is still in the off state. The row scanning signal SN becomes a high level, at this time SN>PWMD, and the seventh switch tube T7 is turned off. Since the seventh switch tube T7 is turned off, there is no voltage at the first end of the eighth switch tube T8, so the eighth switch tube T8 is turned off.

[0159] In the later stage of the comparative light-emitting phase, as the first control signal Sweep1 continues to increase, the voltage at point S also continues to increase. When S>VGH+Vth, the second switch tube T2 is turned on. Under the action of the first control signal Sweep1 and the first capacitor C1, the voltage at point B also gradually increases. When the voltage at point B is greater than PAMD, the fourth switch tube T4 is turned off.

[0160] After the fourth switch tube T4 is turned off, the second control signal Sweep2 also gradually increases, and based on the effect of the second capacitor C2, the voltage at point C also gradually increases. When the voltage at point C is greater than VDD, the fifth switch tube T5 is turned off, and the current flowing through the LED disappears, causing the LED to stop emitting light, thereby achieving grayscale control.

[0161] It should be noted that the present application embodiment is only described by taking the above switch tubes as P-type thin film transistors as an example, and the above switch tubes may also be N-type thin film transistors. For N-type thin film transistors, the voltage difference between the gate and the source Vgs < 0 is in the off state, and Vgs greater than 0 is in the on state.

[0162] If the above switch tubes are all N-type thin film transistors, the levels of the reset signal Reset, the row scanning signal SN, the input light emitting signal EM, the first control signal Sweep1 and the second control signal Sweep2 at different stages are different from the levels of different signals at corresponding stages under the P-type thin film transistor. Based on the principle of N-type thin film transistors, the structural schematic diagram of the pixel driving circuit corresponding to the N-type thin film transistor can be referred to Fig.10As shown, when the second end of the third switch tube T3 receives the low level signal VGL, the timing diagram of the relevant control signal level corresponding to the N-type thin film transistor can be referred to Fig.11 As shown. It should be noted that the second end of the third switch tube T3 can only receive the low-level signal VGL, and the cathode of the diode LED receives the voltage VSS to avoid the input luminous signal EM being at a high level during the comparative luminous phase, thereby affecting the luminous emission of the LED. The driving principle of the pixel driving circuit corresponding to the N-type thin film transistor can refer to the driving principle of the pixel driving circuit corresponding to the above-mentioned P-type thin film transistor, and this application will not repeat it here.

[0163] It should also be noted that the high level signal VGH, the low level signal VGL, the power supply voltage signal VDD and the reference signal Ref can be provided by a DC power supply, and the voltage thereof can satisfy the on and off conditions of the corresponding switch tubes.

[0164] In summary, the pixel driving circuit 20 provided in the embodiment of the present application swaps the signals received by the control end and the first end of the second switch tube T2, that is, the control end of the second switch tube T2 receives the PWMD signal and the high level signal VGH, and the first end receives the reference voltage signal Ref and the first control signal Sweep1. In the comparative light-emitting stage, compared with the prior art, the current of the circuit in which the first switch tube T1, the second switch tube T2 and the third switch tube T3 are all turned on is reduced, and the power consumption is effectively reduced. At the same time, by introducing the second control signal Sweep2 and the second capacitor C2, the multiple switch tubes in the prior art are replaced, so that the pixel driving circuit 20 includes nine switch tubes to realize the light-emitting control of the LED, reducing the number of switch tubes, thereby effectively reducing the occupied pixel area. At the same time, the voltage of the first end of the second switch tube T2 is reset by the ninth switch tube T9 to avoid the residual charge from affecting the on and off of the second switch tube T2. The second switch tube T2 is threshold compensated by the eighth switch tube T8 to eliminate the influence of the drift of the threshold voltage of the second switch tube T2, which is conducive to improving the display effect.

[0165] The embodiment of the present application provides a pixel driving circuit 20, including:

[0166] The first switch tube T1, the control end is used to receive the periodic input light emitting signal EM, the first end is used to receive the high level signal VGH, and the second end is connected to the control end of the second switch tube T2;

[0167] A first capacitor C1, a first end of which is used to receive a periodic first control signal Sweep1, and a second end of which is connected to a first end of a second switch tube T2;

[0168] The second end of the second switch tube T2 is respectively connected to the first end of the third switch tube T3 and the control end of the fourth switch tube T4;

[0169] The control end of the third switch tube T3 is used to receive the input light emitting signal EM, and the second end is used to receive the high level signal VGH or the low level signal VGL;

[0170] A first end of the fourth switch tube T4 is used to receive a PAMD signal, and a second end is connected to a control end of the fifth switch tube T5;

[0171] A second capacitor C2, a first end of which is used to receive a periodic second control signal Sweep2, and a second end of which is connected to a control end of the fifth switch tube T5;

[0172] The sixth switch tube T6 has a control end for receiving the input light emitting signal EM, a first end for receiving the power supply voltage signal VDD, and a second end connected to the first end of the fifth switch tube T5;

[0173] The second end of the fifth switch tube T5 is connected to the LED;

[0174] Among them, the cycles of the input light-emitting signal EM, the first control signal Sweep1 and the second control signal Sweep2 are the same, and the input light-emitting signal EM has a high-low level conversion in each cycle. When the level of the input light-emitting signal EM is the level for controlling the first switch tube T1 to be turned on, the first control signal Sweep1 and the second control signal Sweep2 change linearly.

[0175] The structure of the pixel driving circuit 20 can be referred to Figure 3 or Figure 4 As shown, the specific driving principle can be referred to the above embodiment, and this application will not repeat it here.

[0176] An embodiment of the present application provides a display device, including a control module, a display panel, and a pixel driving circuit provided in the above embodiment;

[0177] The control module is used to output an input light emitting signal EM, a first control signal Sweep1 and a second control signal Sweep2 to control the pixel driving circuit.

[0178] Fig.12 This is a flow chart of a control method for a pixel driving circuit provided in an embodiment of the present application. The method of this embodiment can be executed by the above-mentioned control module and can be implemented by hardware, software, or a combination of hardware and software. Fig.12 As shown, the method includes:

[0179] S1201: Generate an input light-emitting signal, a first control signal and a second control signal, wherein the periods of the input light-emitting signal, the first control signal and the second control signal are the same, and the input light-emitting signal has a high-low level conversion in each period, and when the level of the input light-emitting signal is the level for controlling the conduction of the first switch tube, the first control signal and the second control signal change linearly.

[0180] In some embodiments, each cycle of the input light emitting signal EM, the first control signal Sweep1, and the second control signal Sweep2 includes at least a reset phase, a data input phase, and a comparison light emitting phase.

[0181] In one implementation scenario, if the switch tubes included in the pixel driving circuit 20 are all P-type thin film transistors, based on the principle of P-type thin film transistors, combined with Figure 5 As shown, the input light-emitting signal EM can be controlled to be a high level in the reset stage and the data input stage to control the first switch tube T1, the third switch tube T3 and the sixth switch tube T6 to be in the off state in the reset stage and the data input stage; the input light-emitting signal EM can be controlled to be a low level in the comparative light-emitting stage to control the first switch tube T1, the third switch tube T3 and the sixth switch tube T6 to be in the on state in the comparative light-emitting stage.

[0182] If the second end of the third switch tube T3 receives the low level signal VGL, combined with Figure 5 As shown, at this time in the reset stage and the data input stage, the first control signal Sweep1 is controlled to be a low level.

[0183] In the comparative light-emitting stage, the second switch tube T2 needs to be turned off first and then turned on to input a high voltage to pull up the voltage at point B. The condition that the second switch tube T2 needs to meet for turning on is PWMD+△Sweep>VGH, where △Sweep represents the range of change of the first control signal Sweep1, and VHG is a high-level signal. In the process of gradually increasing the first control signal Sweep1, the above formula requirements can be met, and a high voltage can be output to achieve the driving of the LED, so the first control signal Sweep1 can be controlled to increase linearly in the comparative light-emitting stage.

[0184] If the second end of the third switch tube T3 receives the high level signal VGH, then in the reset stage and the data input stage, the first control signal Sweep1 is controlled to be a low level.

[0185] In the comparative light-emitting stage, the second switch tube T2 needs to be turned on first and then turned off, and when the second switch tube T2 is turned on, the potential of the first end of the second switch tube T2 needs to be low potential to ensure that point B is low potential. Since the voltage of the first end of the second switch tube T2 is PWMD+Vth after the data input stage, that is, in the comparative light-emitting stage, the initial voltage of the first end of the second switch tube T2 is PWMD+Vth, and PWMD+Vth needs to be low potential. After point A changes from PWMD to VGH, the second switch tube T2 needs to remain in the on state, and since the potential of the S end cannot change suddenly, VGH<PWMD+Vth is required, that is, VGH is a low potential smaller than PWMD. At this time, the voltage of the first control signal Sweep1 needs to gradually decrease to reduce the voltage difference Vgs between the control end and the first end of the second switch tube T2, and gradually turn off the second switch tube T2. Based on the second switch tube T2, the low level at point B is converted to a high level to realize the driving of the LED, so the first control signal Sweep1 can be controlled to decrease linearly in the comparative light-emitting stage.

[0186] It should also be noted that the first control signal Sweep1 is at a low level in the data input stage. When entering the comparison light-emitting stage, the first control signal Sweep1 can be converted to a high level and linearly decreased from the high level.

[0187] Based on the principle of P-type thin film transistor, the second control signal Sweep2 can be controlled to be low level in the reset stage and data input stage, and linearly increase in the comparative light-emitting stage. Figure 5 In the later stage of the comparative light-emitting phase, after the fourth switch tube T4 is turned off, due to the increase of the second control signal Sweep2, based on the second capacitor C2, the voltage at point C, i.e., the control end of the fifth switch tube T5, increases, thereby controlling the fifth switch tube T5 to be turned off, causing the LED to stop emitting light.

[0188] In another implementation scenario, if the switch tubes included in the pixel driving circuit 20 are all N-type thin film transistors, based on the principle of N-type thin film transistors, the input light-emitting signal EM can be controlled to be a low level in the reset stage and the data input stage, and to be a high level in the comparison light-emitting stage.

[0189] The second end of the third switch tube T3 receives the low level signal VGL. At this time, the first control signal Sweep1 can be controlled to be high level in the reset stage and the data input stage, and linearly reduced in the comparative light-emitting stage. Fig.11 shown.

[0190] Based on the principle of N-type thin film transistors, the second control signal Sweep2 can be controlled to be at a high level in the reset stage and the data input stage, and to decrease linearly in the comparative light emitting stage.

[0191] It should be noted that after the type of the switch tube included in the pixel driving circuit 20 is determined, the level of the input light-emitting signal EM and the second control signal Sweep2 has nothing to do with the type of voltage received by the second end of the third switch tube T3, and the change trend of the first control signal Sweep1 in the comparative light-emitting stage is related to the type of voltage received by the second end of the third switch tube T3, and the specifics can be referred to the above description. Among them, the voltage type is the low-level signal VGL and the high-level signal VGH received by the second end of the third switch tube T3 mentioned above, and the type of the switch tube includes a P-type thin film transistor and an N-type thin film transistor.

[0192] S1202: Output an input light-emitting signal to the control end of the first switch tube, the control end of the third switch tube, and the control end of the sixth switch tube respectively, output a first control signal to the first capacitor, and output a second control signal to the second capacitor.

[0193] In some embodiments, an input light emitting signal EM is output to a control end of the first switch tube T1, a control end of the third switch tube T3, and a control end of the sixth switch tube T6, respectively, so as to control the first switch tube T1, the third switch tube T3, and the sixth switch tube T6 to be turned on or off in corresponding stages according to the levels of the input light emitting signal EM in different stages.

[0194] A first control signal Sweep1 is output to the first capacitor C1 to adjust the voltage at the first end of the second switch tube T2 and control the on and off of the second switch tube T2.

[0195] The second control signal Sweep2 is output to the second capacitor C2 to adjust the voltage of the control end of the fifth switch tube T5, control the turn-off of the fifth switch tube T5, and further control the light emission of the LED.

[0196] The specific control process based on the input light emitting signal EM, the first control signal Sweep1 and the second control signal Sweep2 can refer to the above embodiments, and the present application will not elaborate on it here.

[0197] The embodiment of the present application provides a control method for a pixel driving circuit, generating a second control signal Sweep2, a first control signal Sweep1 and an input light-emitting signal EM. The input light-emitting signal EM is output to the control end of the first switch tube T1, the control end of the third switch tube T3 and the control end of the sixth switch tube T6 respectively, the first control signal Sweep1 is output to the first capacitor C1, and the second control signal Sweep2 is sent to the second capacitor C2. Based on the second control signal Sweep2, the first control signal Sweep1 and the input light-emitting signal EM, the present application controls the conduction and shutdown of the corresponding switch tubes in the pixel driving circuit 20 to realize the driving of the LED. The method of this embodiment replaces some of the switch tubes included in the pixel driving circuit of the prior art by introducing the second control signal Sweep2 and the second capacitor C2 to control the shutdown of the fifth switch tube T5, thereby reducing the number of switch tubes and the occupied pixel area.

[0198] Fig.13 Schematic diagram of a control device for a pixel driving circuit provided in an embodiment of the present application. Fig.13 As shown, an embodiment of the present application provides a control device 1300 for a pixel driving circuit, including a processor 1301 and a memory 1302 , wherein the memory 1302 stores codes, and the processor 1301 runs the codes stored in the memory 1302 to execute the above method.

[0199] The specific implementation process of the processor 1301 can be found in the above method embodiment, and its implementation principle and technical effect are similar, so this embodiment will not be repeated here.

[0200] In the above Fig.13 In the illustrated embodiment, it should be understood that the processor 1301 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the invention may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0201] The memory 1302 may include a high-speed RAM memory, and may also include a non-volatile storage NVM, such as at least one disk storage.

[0202] The processor 1301 and the memory 1302 can be connected via a bus 1103. The bus 1103 can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus 1103 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus 1103 in the drawings of the present application is not limited to only one bus or one type of bus.

[0203] An embodiment of the present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement a method as described in any of the above method embodiments.

[0204] An embodiment of the present application also provides a computer program product, including a computer program, which can implement the method of any of the above method embodiments when executed by a processor.

[0205] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0206] For ease of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are intended to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A display device, characterized in that: include: Display panel and pixel driving circuit; The display panel includes a plurality of pixels, each pixel including at least one LED; The pixel driving circuit comprises: A first switch tube, the control end of which is used to receive a periodic input light-emitting signal, the first end of which is used to receive a high-level signal, and the second end of which is connected to the control end of the second switch tube; A first capacitor, a first end of which is used to receive a periodic first control signal, and a second end of which is connected to a first end of the second switch tube; The second end of the second switch tube is connected to the first end of the third switch tube and the control end of the fourth switch tube respectively; The control end of the third switch tube is used to receive the input light-emitting signal, and the second end is used to receive the high-level signal or the low-level signal; The first end of the fourth switch tube is used to receive the PAMD signal, and the second end is connected to the control end of the fifth switch tube; A second capacitor, a first end of which is used to receive a periodic second control signal, and a second end of which is connected to the control end of the fifth switch tube; A sixth switch tube, whose control end is used to receive the input light emitting signal, whose first end is used to receive a power supply voltage signal, and whose second end is connected to the first end of the fifth switch tube; The second end of the fifth switch tube is connected to the LED; Among them, the periods of the input light-emitting signal, the first control signal and the second control signal are the same, and the input light-emitting signal has a high-low level conversion in each period. When the level of the input light-emitting signal is the level for controlling the conduction of the first switch tube, the first control signal and the second control signal change linearly.

2. The display device according to claim 1, characterized in that The pixel driving circuit further includes: The seventh switch tube, the control end is used to receive a periodic row scan signal, the first end is used to receive a PWMD signal, and the second end is connected to the control end of the second switch tube; the row scan signal has the same period as the input light-emitting signal, and there is a high and low level conversion in each period.

3. The circuit according to claim 2, characterized in that Also includes: The eighth switch tube has a control end for receiving the row scanning signal, a first end connected to the second end of the seventh switch tube, and a second end connected to the first end of the third switch tube, and is used for performing threshold compensation on the second switch tube.

4. The display device according to claim 3, characterized in that The pixel driving circuit further includes: The ninth switch tube, the control end is used to receive a periodic reset signal, the first end is used to receive a reference voltage signal, and the second end is connected to the first end of the second switch tube; the reset signal has the same period as the input light-emitting signal, and there is a high and low level conversion in each period.

5. The display device according to any one of claims 1 to 4, characterized in that: The pixel driving circuit further includes: The third capacitor has a first end for receiving a power supply voltage signal and a second end connected to the control end of the fourth switch tube.

6. The display device according to claim 4, characterized in that The switch tubes among the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube, the eighth switch tube and the ninth switch tube are P-type thin film transistors or N-type thin film transistors.

7. A display device, characterized in that: include: Display panel and pixel driving circuit; The pixel driving circuit is configured as follows: When the level of the input light-emitting signal is the level for controlling the first switch tube to be turned on, the input light-emitting signal is received through the control end of the first switch tube, the first end receives a high-level signal, and the first switch tube is turned on to set the voltage of the control end of the second switch tube to the voltage corresponding to the high-level signal; Receiving a linearly changing first control signal through the first end of the first capacitor, so that the voltage of the first end of the second switch tube at the second end of the first capacitor changes, controlling the on and off of the second switch tube, and controlling the on and off of the fourth switch tube when the second switch tube is turned on; The input light-emitting signal is received through the control end of the third switch tube, and the second end receives a high level signal or a low level signal, and the third switch tube is turned on, so that when the second switch tube is turned off, the on and off of the fourth switch tube is controlled; The input light emitting signal is received through the control end of the sixth switch tube, and the first end receives the power supply voltage signal, and the sixth switch tube is turned on to set the voltage of the first end of the fifth switch tube to the voltage corresponding to the power supply voltage signal; Receiving a PAMD signal through the first end of the fourth switch tube, so that when the fourth switch tube is turned on, the voltage at the control end of the fifth switch tube is set to PAMD, the fifth switch tube is turned on, and the LED emits light; A linearly changing second control signal is received through the first end of the second capacitor, so that when the fourth switch tube is turned off, the voltage of the fifth switch tube control end at the second end of the second capacitor changes, and the fifth switch tube is controlled to be turned off, and the LED stops emitting light; Among them, the input light-emitting signal, the first control signal and the second control signal are periodic signals with the same period. The input light-emitting signal has a high-low level transition within the period. When the level of the input light-emitting signal is the level for controlling the conduction of the first switch tube, the first control signal and the second control signal change linearly.

8. The display device according to claim 7, characterized in that The pixel driving circuit further includes: a seventh switch tube; The control terminal of the seventh switch tube receives a periodic row scanning signal, and the first terminal receives a PWMD signal, so that when the seventh switch tube is turned on, the voltage of the control terminal of the second switch tube is set to PWMD; The row scanning signal has the same period as the input light emitting signal, and has a high-low level conversion in each period.

9. The display device according to claim 8, characterized in that The pixel driving circuit further includes: an eighth switch tube; A row scanning signal is received through the control end of the eighth switch tube, so that when the eighth switch tube is turned on, threshold compensation is performed on the second switch tube.

10. A pixel driving circuit, characterized in that: include: A first switch tube, the control end of which is used to receive a periodic input light-emitting signal, the first end of which is used to receive a high-level signal, and the second end of which is connected to the control end of the second switch tube; A first capacitor, a first end of which is used to receive a periodic first control signal, and a second end of which is connected to a first end of the second switch tube; The second end of the second switch tube is connected to the first end of the third switch tube and the control end of the fourth switch tube respectively; The control end of the third switch tube is used to receive the input light-emitting signal, and the second end is used to receive the high-level signal or the low-level signal; The first end of the fourth switch tube is used to receive the PAMD signal, and the second end is connected to the control end of the fifth switch tube; A second capacitor, a first end of which is used to receive a periodic second control signal, and a second end of which is connected to the control end of the fifth switch tube; A sixth switch tube, whose control end is used to receive the input light emitting signal, whose first end is used to receive a power supply voltage signal, and whose second end is connected to the first end of the fifth switch tube; The second end of the fifth switch tube is connected to the LED; Among them, the periods of the input light-emitting signal, the first control signal and the second control signal are the same, and the input light-emitting signal has a high-low level conversion in each period. When the level of the input light-emitting signal is the level for controlling the conduction of the first switch tube, the first control signal and the second control signal change linearly.

Images