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, and a display panel comprises a plurality of pixels; the pixel driving circuit comprises a first light-emitting control circuit which comprises a first transistor and a second transistor, the control end of the first transistor receives a light-emitting control signal, the first end of the first transistor receives a first voltage signal VGH, and the second end of the first transistor is connected with the first end of the second transistor; one end of the first capacitor receives a first reference signal and the other end is connected with the control end of the second transistor; one end of the second capacitor receives a second reference signal and the other end is connected with the second end of the second transistor; the input end of the second light-emitting control circuit is connected with the second end of the second transistor, the output end is connected with the LED, and the second light-emitting control circuit is used for controlling the LED according to signals generated by the second end of the second transistor; wherein the light-emitting control signal, the first reference signal and the second reference signal are periodic signals. By introducing the second capacitor and the second reference signal, the power consumption 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 have an increasing penetration rate in display products due to their high brightness and excellent picture quality.

[0003] In the prior art, a driving method combining PAM (Pulse Amplitude Modulation) and PWM (Pulse Width Modulation) is usually used for Mini-LED and Micro-LED high grayscale displays, but this driving method has high driving power consumption. 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 of high driving power consumption when driving Mini-LED and Micro-LED by combining PAM and PWM in the prior art.

[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 is used to display image information, and includes a plurality of pixels, each pixel including at least one LED;

[0007] The pixel driving circuit is used to drive the pixels in the display panel, including:

[0008] A first light emitting control circuit comprises a first transistor and a second transistor, wherein the control end of the first transistor is used to receive a light emitting control signal, the first end is used to receive a first voltage signal VGH, and the second end is connected to the first end of the second transistor;

[0009] A first capacitor, one end of which is used to receive a first reference signal, and the other end of which is connected to the control end of the second transistor;

[0010] A second capacitor, one end of which is used to receive a second reference signal, and the other end of which is connected to the second end of the second transistor;

[0011] a second light emitting control circuit, having an input end connected to the second end of the second transistor and an output end connected to the LED, and being used to control the LED according to a signal generated by the second end of the second transistor;

[0012] Among them, the light-emitting control signal, the first reference signal and the second reference signal are all periodic signals, and the period at least includes a comparative light-emitting stage; in the comparative light-emitting stage, the level of the light-emitting control signal is the level for controlling the conduction of the first transistor, and the first reference signal and the second reference signal are both linearly changing ramp signals.

[0013] In a second aspect, an embodiment of the present application provides a display device, including: a display panel and a pixel driving circuit;

[0014] The pixel driving circuit is configured as:

[0015] In the comparison light-emitting stage, the light-emitting control signal is received through the control end of the first transistor, the first end receives the first voltage signal VGH, the first transistor is turned on to turn on the second transistor, and the second light-emitting control circuit controls the LED to emit light according to the signal generated by the second end of the second transistor;

[0016] A linearly changing first reference signal is received through one end of the first capacitor, so that the voltage of the second transistor control end at the other end of the first capacitor changes, and the second transistor is turned off;

[0017] A linearly changing second reference signal is received through one end of the second capacitor to change the voltage of the second end of the second transistor at the other end of the second capacitor, and the second light-emitting control circuit controls the LED to stop emitting light according to the signal currently generated by the second end of the second transistor.

[0018] In a third aspect, an embodiment of the present application provides a pixel driving circuit, including:

[0019] A first light emitting control circuit comprises a first transistor and a second transistor, wherein the control end of the first transistor is used to receive a light emitting control signal, the first end is used to receive a first voltage signal VGH, and the second end is connected to the first end of the second transistor;

[0020] A first capacitor, one end of which is used to receive a first reference signal, and the other end of which is connected to the control end of the second transistor;

[0021] A second capacitor, one end of which is used to receive a second reference signal, and the other end of which is connected to the second end of the second transistor;

[0022] a second light emitting control circuit, having an input end connected to the second end of the second transistor and an output end connected to the LED, and being used to control the LED according to a signal generated by the second end of the second transistor;

[0023] Among them, the light-emitting control signal, the first reference signal and the second reference signal are all periodic signals, and the period at least includes a comparative light-emitting stage; in the comparative light-emitting stage, the level of the light-emitting control signal is the level for controlling the conduction of the first transistor, and the first reference signal and the second reference signal are both linearly changing ramp signals.

[0024] The present application provides a display device and a pixel driving circuit. The display device includes a display panel and a pixel driving circuit, wherein the display panel is used to display image information, includes a plurality of pixels, and the pixels include at least one LED. The pixel driving circuit is used to drive the pixels in the display panel, specifically as follows: the first end of the first transistor receives a first voltage signal VGH, the control end receives a light-emitting control signal, and the first transistor is turned on to set the voltage of the first end of the second transistor to VGH. As the first reference signal changes linearly, the voltage of the control end of the second transistor also changes accordingly based on the first capacitor. When the first reference signal changes within a certain range, the second transistor remains in the on state, and the second light-emitting control circuit controls the LED to emit light according to the current voltage of the second end of the second transistor. As the first reference signal continues to change, when the first reference signal exceeds the range, the second transistor is turned off. At this time, based on the second reference signal, the second light-emitting control circuit controls the LED to stop emitting light, thereby realizing the driving of the LED. Since the pixel driving circuit of the present application introduces the second reference signal and the second capacitor, some transistors in the prior art are replaced. Based on the capacitance characteristics, the pixel driving circuit of the present application is a path only when the voltage at both ends of the second capacitor changes, and compared with the path formed by connecting multiple transistors, the current flowing through the circuit where the second capacitor is located is smaller, so it can effectively reduce power consumption. At the same time, the present application reduces the number of transistors, which is also conducive to further reducing power consumption and saving the area of ​​the actual pixel.

[0025] 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

[0026] 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.

[0027] Figure 1 A schematic diagram of a planar structure of a display device provided in an embodiment of the present application;

[0028] Figure 2 A structural diagram of a pixel driving circuit in the prior art;

[0029] Figure 3 A schematic diagram of the structure of a display device provided in an embodiment of the present application;

[0030] Figure 4 A schematic diagram of the structure of a pixel driving circuit provided in an embodiment of the present application;

[0031] Figure 5 A timing diagram of related control signal levels corresponding to a P-type thin film transistor provided in an embodiment of the present application;

[0032] Figure 6 A schematic diagram of the structure of a pixel driving circuit corresponding to a P-type thin film transistor in a reset phase provided by an embodiment of the present application;

[0033] Figure 7 A schematic diagram of the structure of a pixel driving circuit corresponding to a P-type thin film transistor in a data input stage provided in an embodiment of the present application;

[0034] Figure 8 A schematic diagram of a pixel driving circuit corresponding to a P-type thin film transistor at an early stage of a comparative light-emitting stage provided by an embodiment of the present application;

[0035] Fig. 9 A schematic structural diagram of a pixel driving circuit corresponding to a P-type thin film transistor in a later light-emitting stage provided by an embodiment of the present application;

[0036] 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;

[0037] Fig.11 A timing diagram of related control signal levels corresponding to an N-type thin film transistor provided in an embodiment of the present application;

[0038] Fig.12 A flow chart of a control method for a pixel driving circuit provided in an embodiment of the present application;

[0039] Fig.13 A schematic diagram of a control device for a pixel driving circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] 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, not all of the embodiments.

[0041] 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.

[0042] 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 ordinary and common meanings.

[0043] 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.

[0044] In addition, the terms "include" and "have" 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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 unusable for driving Micro-LEDs.

[0056] 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, since the driving circuit includes 11 transistors, and in the comparative light-emitting stage, Figure 2 When the transistors 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. At the same time, the circuit contains a large number of transistors, resulting in a large pixel area.

[0057] Based on this, an embodiment of the present application provides a display device, in which a pixel driving circuit included in the display device introduces a second reference signal and a second capacitor. In the later stage of the comparative light-emitting stage, the second reference signal raises or lowers the voltage at the input end of the second light-emitting control circuit through the second capacitor, so that the third transistor is turned off. The present application replaces the original transistor by introducing a second capacitor. Based on the characteristics of the capacitor, only when the voltage at both ends of the second capacitor changes, the circuit where the second capacitor is located is a path, and compared with the path formed by connecting multiple transistors, the current flowing through the circuit where the second capacitor is located is small, so that power consumption can be effectively reduced. At the same time, the present application reduces the number of transistors, which is also conducive to further reducing power consumption and saving the area of ​​the actual pixel.

[0058] Figure 3 This is a schematic diagram of the structure of a display device provided in an embodiment of the present application. Figure 3 As shown, the display device includes: a display panel 10, a pixel driving circuit 20;

[0059] The display panel 10 is used to display image information, and includes a plurality of pixels, each pixel including at least one LED;

[0060] The pixel driving circuit 20 is used to drive the pixels in the display panel 10, including:

[0061] The first light emitting control circuit 201 comprises a first transistor T1 and a second transistor T2, wherein the control end of the first transistor T1 is used to receive the light emitting control signal EM, the first end is used to receive the first voltage signal VGH, and the second end is connected to the first end of the second transistor T2;

[0062] A first capacitor C1, one end of which is used to receive a first reference signal Sweep1, and the other end of which is connected to a control end of a second transistor T2;

[0063] A second capacitor C2, one end of which is used to receive the second reference signal Sweep2, and the other end of which is connected to the second end of the second transistor T2;

[0064] A second light emitting control circuit 202, having an input end connected to the second end of the second transistor T2 and an output end connected to the LED, for controlling the LED according to a signal generated by the second end of the second transistor T2;

[0065] Among them, the light-emitting control signal EM, the first reference signal Sweep1 and the second reference signal Sweep2 are all periodic signals, and the period at least includes a comparative light-emitting stage; in the comparative light-emitting stage, the level of the light-emitting control signal EM is the level for controlling the conduction of the first transistor T1, and the first reference signal Sweep1 and the second reference signal Sweep2 are both linearly changing ramp signals.

[0066] The first transistor T1 is used to set the voltage at the first end of the second transistor T2 to VGH when the first transistor T1 is turned on.

[0067] The second transistor T2 is used to provide a voltage at the second end to the second light emitting control circuit 202, so that the second light emitting control circuit 202 controls whether the LED emits light according to the voltage at the second end of the second transistor T2.

[0068] The first capacitor C1 is used for changing the voltage at the control terminal of the second transistor T2 when the first reference signal Sweep1 changes, so as to control the second transistor T2 to be turned off.

[0069] The second capacitor C2 is used to change the voltage at the second end of the second transistor T2, i.e., the input end of the second light-emitting control circuit 202, based on the change of the second reference signal Sweep2 when the second transistor T2 is turned off, so that the second light-emitting control circuit 202 controls the LED to stop emitting light according to the current voltage at the second end of the second transistor T2.

[0070] The first transistor T1 and the second transistor T2 provided in the embodiment of the present application can be P-type thin film transistors or N-type thin film transistors. The control terminal of the above transistor is the gate of the transistor, and the first terminal and the second terminal can be the source or drain.

[0071] It should be noted that the conduction of the transistor needs to meet certain conditions, and the conduction conditions are related to the type of transistor. The types of transistors include P-type transistors and N-type transistors. In one implementation scenario, the conduction condition of the P-type transistor is Vgs < 0, where Vgs represents the voltage difference between the gate and the source of the transistor, that is, the gate voltage is less than the source voltage. In another implementation scenario, the conduction condition of the N-type transistor is Vgs > 0, that is, the gate voltage is greater than the source voltage.

[0072] The embodiment of the present application provides a display device, including a display panel 10 and a pixel driving circuit 20. In the pixel driving circuit 20, when the first transistor T1 is turned on, the voltage at the first end of the second transistor T2 is set to VGH. As the first reference signal Sweep1 changes linearly, based on the first capacitor C1, the voltage at the control end of the second transistor T2 also changes accordingly. When the first reference signal Sweep1 changes within a certain range, the second transistor T2 remains in the on state. The second light-emitting control circuit 202 controls the LED to emit light according to the current voltage at the second end of the second transistor T2. As the first reference signal Sweep1 continues to change, when the first reference signal Sweep1 exceeds the range, the second transistor T2 is turned off. At this time, based on the changed second reference signal Sweep2 and the second capacitor C2, the second light-emitting control circuit 202 can control the LED to stop emitting light, thereby realizing the driving of the LED. Since the pixel driving circuit 20 of the present application introduces the second reference signal Sweep2 and the second capacitor C2, some of the original transistors in the prior art are replaced. Based on the capacitance characteristics, the pixel driving circuit 20 of the present application is a path only when the voltage at both ends of the second capacitor C2 changes, and the circuit where the second capacitor C2 is located is a path, and compared with the path formed by connecting multiple transistors, the current flowing through the circuit where the second capacitor C2 is located is smaller, so it can effectively reduce power consumption. At the same time, the present application reduces the number of transistors, which is also conducive to further reducing power consumption and saving the area of ​​the actual pixel.

[0073] Figure 4 A schematic diagram of a pixel driving circuit provided in an embodiment of the present application. Figure 4 As shown, the second light emitting control circuit 202 in the pixel driving circuit 20 includes: a third transistor T3, a fourth transistor T4, a fifth transistor T5 and a third capacitor C3.

[0074] The control end of the third transistor T3 is connected to the second end of the second transistor T2, the first end of the third transistor T3 is used to receive the PAMD signal, the PAMD signal is the voltage value when the LED light brightness is the highest, and the second end of the third transistor T3 is respectively connected to the control end of the fourth transistor T4 and one end of the third capacitor C3;

[0075] The control end of the fifth transistor T5 is used to receive the light emitting control signal EM, the first end is used to receive the second voltage signal VDD, and the second end is connected to the first end of the fourth transistor T4; the second end of the fourth transistor T4 is connected to one end of the LED; the other end of the LED is used to receive the light emitting control signal EM;

[0076] The other end of the third capacitor C3 is used to receive the third reference signal Sweep3. The third reference signal Sweep3 is a periodic signal, and the period at least includes a comparison light-emitting stage. In the comparison light-emitting stage, the third reference signal Sweep3 is a ramp signal that changes linearly synchronously with the first reference signal Sweep1 and the second reference signal Sweep2.

[0077] The fifth transistor T5 is used for setting the voltage at the first end of the fourth transistor T4 to VDD when the fifth transistor T5 is turned on.

[0078] The third transistor T3 is used for setting the voltage at the control terminal of the fourth transistor T4 to PAMD when the third transistor T3 is turned on, so as to turn on the fourth transistor T4.

[0079] The fourth transistor T4 is used to control whether the LED emits light. When the fourth transistor T4 is turned on, the LED emits light. When the fourth transistor T4 is turned off, the current flowing through the LED disappears and the LED stops emitting light.

[0080] The third capacitor C3 is used for changing the voltage at the control end of the fourth transistor T4 when the third transistor T3 is turned off and the third reference signal Sweep3 changes, so that the fourth transistor T4 is turned off and the LED stops emitting light.

[0081] In one or more embodiments of the present application, reference is still made to Figure 4 As shown, the pixel driving circuit 20 further includes: a sixth transistor T6 and a seventh transistor T7;

[0082] The control end of the sixth transistor T6 is used to receive the row scanning signal SN, and the other two ends are respectively connected to the control end of the second transistor T2 and the second end of the second transistor T2 to perform threshold compensation on the second transistor T2;

[0083] The control end of the seventh transistor T7 is used to receive the row scanning signal SN, the first end is used to receive the PWMD signal, and the second end is connected to the first end of the second transistor T2;

[0084] Among them, the PWMD signal is a voltage value that changes according to the brightness of the LED; the row scan signal SN is a periodic signal, and the period at least includes a data input stage and a comparison light-emitting stage, and the data input stage is before the comparison light-emitting stage; in the data input stage and the comparison light-emitting stage, the level of the row scan signal SN is different; in the comparison light-emitting stage, the level of the row scan signal is different from that of the light-emitting control signal.

[0085] In some embodiments, the row scan signal SN received by the control end of the seventh transistor 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. The seventh transistor T7 is used to set the voltage of the first end of the second transistor T2 to PWMD when it is turned on.

[0086] The sixth transistor T6 is used to connect the control terminal and the second terminal of the second transistor T6 to form a diode structure when it is turned on, so as to perform threshold compensation on the second transistor T2, which is beneficial to eliminate the influence of the threshold voltage offset of the second transistor T2.

[0087] Still refer to Figure 4 As shown, the pixel driving circuit 20 further includes: an eighth transistor T8. The control terminal of the eighth transistor T8 is used to receive the reset signal Reset, the first terminal is used to receive the reference voltage signal Ref, and the second terminal is connected to the control terminal of the second transistor T2.

[0088] Among them, the reset signal Reset is a periodic signal, and the period at least includes a reset stage, a data input stage and a comparison and light-emitting stage. The reset stage is before the data input stage, and the data input stage is before the comparison and light-emitting stage; in the data input stage and the comparison and light-emitting stage, the level of the reset signal Reset remains consistent and is different from the level in the reset stage; in the comparison and light-emitting stage, the level of the reset signal Reset is consistent with the level of the row scanning signal SN.

[0089] The eighth transistor T8 is used to initialize the voltage at the control end of the second transistor T2 to clear the remaining charge at the control end of the second transistor T2 to prevent the remaining charge from affecting the on-off of the second transistor T2 and further affecting the driving of the LED.

[0090] The transistors among the first transistor T1 , the second transistor T2 , the third transistor T3 , the fourth transistor T4 , the fifth transistor T5 , the sixth transistor T6 , the seventh transistor T7 and the eighth transistor T8 are P-type thin film transistors or N-type thin film transistors.

[0091] The embodiment of the present application provides a display device, the second light-emitting control circuit 202 introduces a third reference signal Sweep3 and a third capacitor C3, and as the third reference signal Sweep3 changes, based on the third capacitor C3, the fourth transistor T4 can be controlled to turn off to control the LED to stop emitting light. The second light-emitting control circuit 202 of the present application introduces the third capacitor C3 to replace the transistor in the prior art. Based on the capacitance characteristics, only when the voltage at both ends of the third capacitor C3 changes, the circuit where the third capacitor C3 is located is a path, and compared with the path formed by connecting multiple transistors, the current flowing through the circuit where the third capacitor C3 is located is small, so it can effectively reduce power consumption. At the same time, the present application reduces the number of transistors, which is also conducive to further reducing power consumption and saving the area of ​​the actual pixel. At the same time, the threshold compensation of the second transistor T2 is performed by the sixth transistor T6, which is conducive to eliminating the influence of the drift of the threshold voltage Vth of the second transistor T2 to improve the display effect. The voltage at the control end of the second transistor T2 can be reset by the eighth transistor T8 to eliminate the influence of the voltage at the control end of the second transistor T2 in the previous cycle.

[0092] On the basis of the above-mentioned embodiment, a display device is provided below, and the driving process of the pixel driving circuit 20 in the display device is described in detail.

[0093] The embodiment of the present application provides a display device, including a display panel 10 and a pixel driving circuit 20;

[0094] The pixel driving circuit 20 is configured as follows:

[0095] In the comparison light-emitting stage, the control terminal of the first transistor T1 receives the light-emitting control signal EM, the first terminal receives the first voltage signal VGH, the first transistor T1 is turned on, so that the second transistor T2 is turned on, and the second light-emitting control circuit 202 controls the LED to emit light according to the signal generated at the second terminal of the second transistor T2;

[0096] A linearly changing first reference signal Sweep1 is received through one end of the first capacitor C1, so that the voltage of the control end of the second transistor T2 at the other end of the first capacitor C1 changes, and the second transistor T2 is turned off;

[0097] The second reference signal Sweep2 that changes linearly is received through one end of the second capacitor C2 to change the voltage of the second end of the second transistor T2 at the other end of the second capacitor C2. The second light-emitting control circuit 202 controls the LED to stop emitting light according to the signal currently generated by the second end of the second transistor T2.

[0098] In some embodiments, the first transistor T1 and the second transistor T2 are P-type thin film transistors, the first end is the source, and the second end is the drain. Based on the conduction principle of the P-type thin film transistor, the light control signal EM can be set to a low level in the light comparison stage, and the first reference signal Sweep1 and the second reference signal Sweep2 can be linearly increased synchronously.

[0099] The structure of the pixel driving circuit 20 can be referred to Figure 4 As shown, in the comparative light-emitting stage, the control end of the first transistor T1 receives the light-emitting control signal EM, and the first end receives the first voltage signal VGH. At this time, since the light-emitting control signal EM is at a low level, EM<VGH, the first transistor T1 is turned on, and the voltage of the first end of the second transistor T2 is set to VGH.

[0100] One end of the first capacitor C1 receives the first reference signal Sweep1. As the first reference signal Sweep1 gradually increases, based on the effect of the first capacitor C1, the voltage at the control end of the second transistor T2 also gradually increases. When the voltage at the control end of the second transistor T2 is less than the voltage VGH at the first end, the second transistor T2 is in the on state, and the voltage at the second end of the second transistor T2 is set to VGH through the first transistor T1 and the second transistor T2. The voltage at the second end of the second transistor T2 is the voltage at the input end of the second light-emitting control circuit 202, and the second light-emitting control circuit 202 can control the LED to emit light based on the voltage.

[0101] As the first reference signal Sweep1 continues to increase, the voltage at the control terminal of the second transistor T2 also continues to increase, causing the voltage at the control terminal of the second transistor T2 to be greater than the voltage VGH at the first terminal, and the second transistor T2 is turned off.

[0102] After the second transistor T2 is turned off, as the second reference signal Sweep2 gradually increases, the voltage at the second end of the second transistor T2 also gradually increases due to the action of the second capacitor C2. When the voltage at the second end of the second transistor T2 is greater than a certain threshold, the second light control circuit 202 controls the LED to stop emitting light.

[0103] In some embodiments, the second light emitting control circuit 202 is configured as follows:

[0104] In the comparison light-emitting stage, the control end of the fifth transistor T5 receives the light-emitting control signal EM, and the first end receives the second voltage signal VDD, and the fifth transistor T5 is turned on to set the voltage of the first end of the fourth transistor T4 to VDD;

[0105] When the second transistor T2 is turned on, the control end of the third transistor T3 receives the signal generated by the second end, and the first end receives the PAMD signal, and the third transistor T3 is turned on to turn on the fourth transistor T4 to control the LED to emit light;

[0106] A linearly changing second reference signal Sweep2 is received through one end of the second capacitor C2, so that the voltage of the control end of the third transistor T3 at the other end of the second capacitor C2 changes, and the third transistor T3 is turned off;

[0107] A third reference signal Sweep3 that changes linearly is received through one end of the third capacitor C3, so that the voltage of the control end of the fourth transistor T4 at the other end of the third capacitor C3 changes, and the fourth transistor T4 is turned off to control the LED to stop emitting light;

[0108] The third reference signal Sweep3 is a ramp signal that changes linearly synchronously with the first reference signal Sweep1 and the second reference signal Sweep2 .

[0109] Still taking the third transistor T3 , the fourth transistor T4 and the fifth transistor T5 as P-type thin film transistors as an example, in the comparative light emission stage, the third reference signal Sweep3 increases linearly synchronously with the first reference signal Sweep1 and the second reference signal Sweep2 .

[0110] In one implementation scenario, in the comparative light-emitting stage, when the first reference signal Sweep1 increases, but the second transistor T2 is in the on state, the voltage at the second end of the second transistor T2 is VGH, that is, the voltage at the control end of the third transistor T3 is VGH. Since VGH<PAMD, the third transistor T3 is turned on, and the voltage at the control end of the fourth transistor T4 is set to PAMD.

[0111] In the comparative light-emitting stage, since the control terminal of the fifth transistor T5 receives the low-level light-emitting control signal EM, the first terminal receives the second voltage signal VDD, EM<VDD, the fifth transistor T5 is turned on, and the voltage of the first terminal of the fourth transistor T4 is set to VDD. Since PAMD<VDD, the fourth transistor T4 is turned on.

[0112] Since one end of the LED is connected to the second end of the fourth transistor T4, the voltage of the end is the voltage of the second end of the fourth transistor T4. The other end of the LED receives the light-emitting control signal EM, and at this time there is a voltage difference between the two ends of the LED, and the LED emits light. In an implementation scenario, the anode of the LED is connected to the second end of the fourth transistor T4, and the cathode of the LED receives the light-emitting control signal EM.

[0113] As the first reference signal Sweep1 continues to increase, the voltage at the control terminal of the second transistor T2, namely point A, continues to increase due to the effect of the first capacitor C1. When the voltage at the control terminal of the second transistor T2 is greater than the voltage at the first terminal, the second transistor T2 is turned off.

[0114] After the second transistor T2 is turned off, as the second reference signal Sweep2 gradually increases, based on the action of the second capacitor C2, the voltage at the second end of the second transistor T2, i.e., the control end of the third transistor T3, also increases. When the voltage at the control end of the third transistor T3 is greater than PAMD, the third transistor T3 is turned off.

[0115] As the third reference signal Sweep3 gradually increases, the voltage at the control end of the fourth transistor T4 increases accordingly. When the voltage at the control end of the fourth transistor T4 is greater than the voltage VDD at the first end, the fourth transistor T4 is turned off, causing the current flowing through the LED to disappear and the LED stops emitting light.

[0116] In summary, the embodiment of the present application provides a display device, in the comparative light-emitting stage, based on the first reference signal Sweep1 and the first capacitor C1, the conduction and shutoff of the second transistor T2 are controlled, and when the second transistor T2 is turned off, the voltage at the input end of the second light-emitting control circuit 202 is adjusted by introducing the second reference signal Sweep2 and the second capacitor C2, so that the second light-emitting control circuit 202 controls the LED to stop emitting light. The present application replaces some of the original transistors in the prior art by introducing the second reference signal Sweep2 and the second capacitor C2. Based on the capacitance characteristics, when the second reference signal Sweep2 changes, the circuit where the second capacitor C2 is located is a path, and compared with the path formed by connecting multiple transistors, the current flowing through the circuit where the second capacitor C2 is located is smaller, thereby effectively reducing power consumption. At the same time, the number of transistors is reduced, which is conducive to further reducing power consumption while also saving the area of ​​the actual pixel.

[0117] In one or more embodiments of the present application, the pixel driving circuit 20 is further configured as:

[0118] In the data input stage, the control end of the seventh transistor T7 receives the row scan signal SN, the first end receives the PWMD signal, and the seventh transistor T7 is turned on to turn on the second transistor T2;

[0119] The control terminal of the sixth transistor T6 receives the row scanning signal SN, and the sixth transistor T6 is turned on to perform threshold compensation on the second transistor T2;

[0120] Among them, the PWMD signal is a voltage value that changes according to the brightness of the LED; the row scan signal SN is a periodic signal, and the period at least includes a data input stage and a comparison light-emitting stage, and the data input stage is before the comparison light-emitting stage; in the data input stage and the comparison light-emitting stage, the level of the row scan signal SN is different; in the comparison light-emitting stage, the level of the row scan signal SN is different from that of the light-emitting control signal EM.

[0121] The sixth transistor T6 and the seventh transistor T7 are used in the data input stage of the pixel driving process. The data input stage is located before the comparison and light emission stage, and is the process of the pixel driving circuit 20 receiving the PWMD signal. In some embodiments, the sixth transistor T6 and the seventh transistor T7 are still described as P-type thin film transistors as an example. Based on the conduction principle of the P-type thin film transistor, the row scanning signal SN is at a low level in the data input stage and at a high level in the comparison and light emission stage.

[0122] Specifically, the structure of the pixel driving circuit 20 can refer to Figure 4 As shown. In the data input stage, the control end of the seventh transistor T7 receives the low-level row scanning signal SN, and the first end receives the PWMD signal. SN<PWMD, so the seventh transistor T7 is turned on, and the voltage of the first end of the second transistor T2 is set to PWMD. At this time, the voltage of the control end of the second transistor T2 is less than PWMD, so that the second transistor T2 is turned on. Among them, the PWMD signal is a voltage value that changes according to the brightness of the LED.

[0123] In one implementation scenario, before the data input stage, a reset stage may be included to reset the voltage at the control end of the second transistor T2 to ensure that after the reset, the voltage at the control end of the second transistor T2 is less than PWMD.

[0124] In the data input stage, the control end of the sixth transistor T6 also receives the low-level row scanning signal SN. Since the voltage at the control end of the second transistor T2 is the voltage at the first end of the sixth transistor T6, the voltage at the control end of the sixth transistor T6 is less than the voltage at the first end, and the sixth transistor T6 is turned on.

[0125] Since the sixth transistor T6 is turned on, the control end of the second transistor T2 is connected to its second end, that is, point AB is connected to form a diode structure, so the voltage of the second end of the second transistor T2, that is, the voltage of point B, is set to PWMD+Vth, which in turn causes the voltage of the control end of the second transistor T2 to become PWMD+Vth, so as to perform threshold compensation on the second transistor T2, wherein Vth is the threshold voltage of the second transistor T2.

[0126] Since point AB is connected, the voltage at point A, i.e., the control terminal of the second transistor T2, also increases to PWMD+Vth. At this time, since the voltage at the control terminal of the second transistor T2 is greater than the voltage at the first terminal, the second transistor T2 is turned off, and the threshold voltage Vth of the second transistor T2 can be stored on the second capacitor C2.

[0127] In summary, performing threshold compensation on the second transistor T2 through the sixth transistor T6 is beneficial to eliminating the influence caused by the offset of the threshold voltage Vth of the second transistor T2, so as to improve the display effect.

[0128] In one or more embodiments of the present application, the first reference signal Sweep1, the second reference signal Sweep2, the third reference signal Sweep3 and the light emitting control signal EM further include a reset phase and a data input phase within a cycle, and the reset phase is located before the data input phase;

[0129] The level of the light emitting control signal EM in the reset phase and the data input phase is consistent, and is different from the level in the comparison light emitting phase;

[0130] The level of the first reference signal Sweep1 in the reset phase is consistent with that in the data input phase, and is consistent with the level of the light emitting control signal EM in the reset phase;

[0131] The level of the second reference signal Sweep2 in the reset phase and the data input phase is consistent, and is different from the level of the first reference signal Sweep1 in the reset phase;

[0132] The level of the third reference signal Sweep3 in the reset phase and the data input phase is consistent, and is consistent with the level of the second reference signal Sweep2 in the reset phase;

[0133] The row scanning signal SN also includes a reset phase in its cycle. The reset phase is located before the data input phase, and the level of the reset phase is consistent with the level of the comparison light-emitting phase.

[0134] If the first transistor T1 to the eighth transistor T8 are all P-type thin film transistors, the timing diagram of the relevant control signal levels corresponding to the P-type thin film transistors can refer to Figure 5 shown.

[0135] Taking a P-type thin film transistor as an example, the specific driving processes of the reset stage, the data input stage and the comparative light-emitting stage in the LED driving process are described in detail below.

[0136] Reset phase:

[0137] Figure 6 A schematic diagram of the structure of a pixel driving circuit corresponding to a P-type thin film transistor in 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 a low-level signal. At this time, the control end of the eighth transistor T8 receives the reset signal Reset, and the first end receives the reference voltage signal Ref. Since Reset<Ref, the eighth transistor T8 is turned on, and the voltage at point A, i.e., the control end of the second transistor T2, is set to the reference voltage Ref.

[0138] In the reset phase, since the row scanning signal SN is at a high level, for the sixth transistor T6, since SN>Ref, the sixth transistor T6 is turned off. For the seventh transistor T7, since SN>PWMD, the seventh transistor T7 is turned off.

[0139] In the reset phase, since the light emitting control signal EM is at a high level, for the first transistor T1, EM>VGH, so the first transistor T1 is turned off. For the fifth transistor T5, since EM>VDD, the fifth transistor T5 is turned off.

[0140] Since the first transistor T1 is turned off, there is no voltage at the first end of the second transistor T2, causing the second transistor T2 to be turned off.

[0141] Since the second transistor T2 is turned off and the second reference signal Sweep2 is at a low level and remains unchanged, based on the basic characteristics of the capacitor, the circuit where the second capacitor C2 is located can be regarded as an open circuit. Therefore, there is no voltage at the control end of the third transistor T3, causing the third transistor T3 to be turned off.

[0142] Since the third transistor T3 is turned off and the third reference signal Sweep3 is at a low level and remains unchanged, based on the basic characteristics of the capacitor, the circuit where the third capacitor C3 is located can be regarded as an open circuit. Therefore, there is no voltage at the control end of the fourth transistor T4, and the fourth transistor T4 is turned off, causing the LED to not emit light in the reset stage.

[0143] In the reset phase, the first reference signal Sweep1 is at a high level and remains unchanged. Based on the basic characteristics of capacitors, the circuit where the first capacitor C1 is located can be regarded as an open circuit.

[0144] Data entry phase:

[0145] Figure 7 A schematic diagram of a pixel driving circuit corresponding to a P-type thin film transistor in a data input stage provided by an embodiment of the present application. Figure 5 and Figure 7 It can be seen that in the data input stage, the row scanning signal SN is at a low level, at this time, for the sixth transistor T6, SN<Ref, so the sixth transistor T6 is turned on. For the seventh transistor T7, SN<PWMD, so the seventh transistor T7 is turned on.

[0146] Since the seventh transistor T7 is turned on, the voltage at the first end of the second transistor T2 is set to PWMD. At this time, the voltage at the control end of the second transistor T2 is the reference voltage Ref, Ref<PWMD, causing the second transistor T2 to be turned on.

[0147] Since the sixth transistor T6 is turned on, points AB are connected to form a diode structure, so the voltage at point B is PWMD+Vth, and the voltage at point A will gradually increase to PWMD+Vth to perform threshold compensation on the second transistor T2, where Vth is the threshold voltage of the second transistor T2.

[0148] When the voltage at point A increases to PWMD+Vth, PWMD+Vth>PWMD, the second transistor T2 is turned off, and the threshold voltage Vth of the second transistor T2 is stored on the capacitor C2, and the data input phase ends.

[0149] At the same time, since the voltage at point B is PWMD+Vth, that is, the voltage at the control end of the third transistor T3 is PWMD+Vth, the first end of the third transistor T3 receives the PAMD signal, PWMD+Vth>PAMD, causing the third transistor T3 to be turned off.

[0150] In the data input stage, since the reset signal Reset is at a high level, Reset>Ref, the eighth transistor T8 is turned off. The light emitting control signal EM is at a high level, since EM>VGH, the first transistor T1 is turned off. Since EM>VDD, the fifth transistor T5 is turned off.

[0151] Since the third transistor T3 and the fifth transistor T5 are both turned off, the fourth transistor T4 is turned off, thereby causing the LED to not emit light during the data input stage.

[0152] In the data input stage, the first reference signal Sweep1 is still at a high level, and the second reference signal Sweep2 and the third reference signal Sweep3 are still at a low level. Based on the basic characteristics of capacitors, the circuits where the first capacitor C1, the second capacitor C2 and the third capacitor C3 are located can be regarded as open circuits.

[0153] Compare the luminous phases:

[0154] In the comparative light emitting stage, the comparative light emitting stage can be divided into an early stage and a late stage according to the conduction state of the second transistor T2.

[0155] Figure 8 A schematic diagram of the structure of a pixel driving circuit corresponding to a P-type thin film transistor in an early stage of a comparative light-emitting phase provided by an embodiment of the present application. Figure 5 and Figure 8It can be seen that at the beginning of the comparative light-emitting stage, the reset signal Reset is at a high level, Reset>Ref, so the eighth transistor T8 is turned off. The row scanning signal SN is at a high level, because SN>PWMD+Vth, the sixth transistor T6 is turned off. Because SN>PWMD, the seventh transistor T7 is turned off.

[0156] At the beginning of the comparative light-emitting stage, the light-emitting control signal EM is at a low level. Since EM<VGH, the first transistor T1 is turned on. Since EM<VDD, the fifth transistor T5 is turned on. The first reference signal Sweep1 is converted from a high level to a low level and increases linearly, and the second reference signal Sweep2 and the third reference signal Sweep3 also increase linearly.

[0157] Since the first transistor T1 is turned on, the first terminal of the first transistor T1 receives the first voltage signal VGH, so the voltage of the first terminal of the second transistor T2 is set to VGH. Since the first reference signal Sweep1 is converted from a high level to a low level when entering the comparative light-emitting stage, based on the first capacitor C1, the voltage at point A, i.e., the control terminal of the second transistor T2, will also decrease, so that the second transistor T2 is turned on again.

[0158] At this time, the voltage difference between the control terminal and the first terminal of the second transistor T2, that is, the voltage difference between the gate and the source Vgs=VA-VGH, wherein VA represents the current voltage of the control terminal of the second transistor T2, that is, point A. Since the voltage at point A at this time already includes the threshold voltage Vth, the internal compensation of the second transistor T2 is completed.

[0159] As the first reference signal Sweep1 gradually increases, the voltage at point A also gradually increases based on the first capacitor C1, and when A<VGH+Vth, the second transistor T2 remains turned on. At this time, point B is charged with VGH through the first transistor T1 and the second transistor T2, that is, the voltage at the control end of the third transistor T3 is VGH.

[0160] The first terminal of the third transistor T3 receives the PAMD signal, controls VGH < PAMD, and the third transistor T3 is turned on. Point C is charged with PAMD through the third transistor T3, that is, the voltage at the control terminal of the fourth transistor T4 is PAMD. In one implementation scenario, VGH can be controlled to be a low level to turn on the third transistor T3.

[0161] Since the fifth transistor T5 is turned on, the voltage at the first end of the fourth transistor T4 is set to VDD. PAMD is controlled to be less than VDD, at which time the fourth transistor T4 is turned on and the LED starts to emit light.

[0162] Fig. 9 This is a schematic diagram of the structure of a pixel driving circuit corresponding to a P-type thin film transistor in a later light-emitting stage provided by an embodiment of the present application. Figure 5 and Fig. 9 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 eighth transistor T8 is turned off. The row scanning signal SN is still at a high level, because SN>PWMD+Vth, the sixth transistor T6 is turned off. Because SN>PWMD, the seventh transistor T7 is turned off.

[0163] In the later stage of the comparative light-emitting phase, the light-emitting control signal EM is still at a low level. Since EM<VGH, the first transistor T1 is still in the on state. Since EM<VDD, the fifth transistor T5 is still in the on state. The first reference signal Sweep1 still increases linearly, and the second reference signal Sweep2 and the third reference signal Swee3 also still increase linearly.

[0164] As the first reference signal Sweep1 continues to increase, the voltage at point A also gradually increases. When A>VGH+Vth, the second transistor T2 is turned off.

[0165] As the second reference signal Sweep2 increases, the voltage at point B continues to increase based on the second capacitor C2. When the voltage at point B is greater than PAMD, the third transistor T3 is turned off.

[0166] As the third reference signal Sweep3 increases, the voltage at point C continues to increase based on the third capacitor C3. When the voltage at point C is greater than VDD, the fourth transistor T4 is turned off, and the current flowing through the LED disappears, so that the LED stops emitting light and the gray scale is controlled.

[0167] It should be noted that after the comparison light-emitting phase ends, the voltage at point B remains high based on the second reference signal Sweep2, and the third reference signal Sweep3 is converted from high level to low level, which can reduce the voltage at point C through coupling, thereby reducing the stress of the fourth transistor T4.

[0168] It should also be noted that, since the second transistor T2 needs to be turned on first and then turned off in the comparison light-emitting stage, and the voltage VGH of the first end of the second transistor T2 is a fixed voltage, the voltage difference Vgs between the control end and the first end of the second transistor T2 needs to be negative first and then positive, and the voltage of the first reference signal Sweep1 needs to continue to increase. Therefore, in the embodiment of the present application, the first reference signal Sweep1 has a downward stage after the first capacitor C1 stores the potential, that is, from the data input stage to the comparison light-emitting stage, that is, the voltage at point A is reduced to turn on the second transistor T2. For details, please refer to Figure 5 : The timing diagram corresponding to the first reference signal Sweep1.

[0169] It should be noted that the above embodiments are all described in detail by taking the first transistor T1 to the eighth transistor T8 as P-type thin film transistors as an example. When the above transistors are all N-type thin film transistors, the structural diagram of the pixel driving circuit corresponding to the N-type thin film transistor can be referred to Fig.10 As shown, the timing diagram of the relevant control signal level corresponding to the N-type thin film transistor can be referred to Fig.11 shown.

[0170] Combination Figure 5 and Fig.11 It can be seen that the levels of the reset signal Reset, the row scanning signal SN, the light emitting control signal EM, the first reference signal Sweep1, the second reference signal Sweep2 and the third reference signal Sweep3 corresponding to the N-type thin film transistor at different stages are different from the levels of the P-type thin film transistor at the corresponding stages. Based on the conduction condition of the N-type thin film transistor, the driving principle of the N-type thin film transistor included in the pixel driving circuit can refer to the implementation principle of the above-mentioned P-type thin film transistor, so this application will not be repeated here.

[0171] In summary, the pixel driving circuit 20 introduces the second reference signal Sweep2 and the second capacitor C2. In the later stage of the comparative light-emitting stage, the second reference signal Sweep2 raises the voltage at point B through the second capacitor C2, so that the third transistor T3 is turned off. By introducing the third reference signal Sweep3 and the third capacitor C3, when the third transistor T3 is turned off, the third reference signal Sweep3 raises the voltage at point C through the third capacitor C3, so that the fourth transistor T4 is turned off, and the driving of the LED is realized. Compared with the prior art, the second capacitor C2 and the third capacitor C3 are introduced to replace the original transistor. Only when the voltage at both ends of the second capacitor C2 changes, the circuit where the second capacitor C2 is located is a passage, and only when the voltage at both ends of the third capacitor C3 changes, the circuit where the third capacitor C3 is located is a passage, and compared with the passage formed by connecting multiple transistors, the current flowing through the circuit where the second capacitor C2 and the circuit where the third capacitor C3 are located is small, so it can effectively reduce power consumption. At the same time, the present application reduces the number of transistors, which is also conducive to further reducing power consumption and saving the area of ​​the actual pixel.

[0172] An embodiment of the present application provides a pixel driving circuit, comprising:

[0173] The first light emitting control circuit 201 comprises a first transistor T1 and a second transistor T2, wherein the control end of the first transistor T1 is used to receive the light emitting control signal EM, the first end is used to receive the first voltage signal VGH, and the second end is connected to the first end of the second transistor T2;

[0174] A first capacitor C1, one end of which is used to receive a first reference signal Sweep1, and the other end of which is connected to a control end of a second transistor T2;

[0175] A second capacitor C2, one end of which is used to receive the second reference signal Sweep2, and the other end of which is connected to the second end of the second transistor T2;

[0176] A second light emitting control circuit 202, having an input end connected to the second end of the second transistor T2 and an output end connected to the LED, for controlling the LED according to a signal generated by the second end of the second transistor T2;

[0177] Among them, the light-emitting control signal EM, the first reference signal Sweep1 and the second reference signal Sweep2 are all periodic signals, and the period at least includes a comparative light-emitting stage; in the comparative light-emitting stage, the level of the light-emitting control signal EM is the level for controlling the conduction of the first transistor T1, and the first reference signal Sweep1 and the second reference signal Sweep2 are both linearly changing ramp signals.

[0178] In some embodiments, the structure of the pixel driving circuit can refer to Figure 3 The structure of the pixel driving circuit 20 shown in FIG. 1 and its specific driving process may refer to other embodiments, which will not be described in detail in this application.

[0179] 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;

[0180] The control module is used to output the light emitting control signal EM, the first reference signal Sweep1 and the second reference signal Sweep2 to control the pixel driving circuit 20 . The control process may refer to other embodiments and will not be described in detail here.

[0181] In some embodiments, the display device may be a Mini-LED or Micro-LED display device, and each liquid crystal pixel is driven by a thin film transistor integrated therebehind.

[0182] Fig.12 The flowchart of a control method of a pixel driving circuit provided in an embodiment of the present application is used to control the above-mentioned pixel driving circuit 20. The method of this embodiment can be executed by a control module and can be implemented by hardware, software, or a combination of hardware and software. Fig.12 As shown, the method may include:

[0183] S1201: Generate a light-emitting control signal, a first reference signal and a second reference signal, wherein the light-emitting control signal, the first reference signal and the second reference signal are all periodic signals, and the period at least includes a comparative light-emitting stage; in the comparative light-emitting stage, the level of the light-emitting control signal is the level for controlling the conduction of the first transistor, and the first reference signal and the second reference signal are both linearly changing ramp signals.

[0184] In one implementation scenario, if all transistors included in the pixel driving circuit 20 are P-type thin film transistors, combined with Figure 5 As shown, based on the characteristics of the P-type thin film transistor, in the comparative light emitting stage, the light emitting control signal EM can be controlled to be low level, the first reference signal Sweep1 increases linearly from a low level, and the second reference signal Sweep2 increases linearly synchronously with the first reference signal Sweep1.

[0185] In another implementation scenario, if the transistors included in the pixel driving circuit 20 are all N-type thin film transistors, the levels of the above signals at different stages are different from the levels of P-type thin film transistors at the corresponding stages. Specifically, based on the characteristics of N-type thin film transistors, in the comparative light emitting stage, the light emitting control signal EM can be controlled to be a high level, the first reference signal Sweep1 can be linearly reduced from a high level, and the second reference signal Sweep2 can be linearly reduced synchronously with the first reference signal Sweep1. For details, please refer to Fig.11 shown.

[0186] In another implementation scenario, the transistors in the pixel driving circuit 20 may also include P-type thin film transistors and N-type thin film transistors. In this case, the level of the above signal needs to be controlled according to the type of transistors at corresponding positions.

[0187] S1202: outputting a light emitting control signal to the control terminal of the first transistor, outputting a first reference signal to the first capacitor, and outputting a second reference signal to the second capacitor.

[0188] In some embodiments, a light emitting control signal EM is output to the control terminal of the first transistor T1 to control the first transistor T1 to be turned on in the comparison light emitting stage according to the level of the light emitting control signal EM in the comparison light emitting stage.

[0189] The first reference signal Sweep1 is output to the first capacitor C1 to adjust the voltage of the control terminal of the second transistor T2 to control the on and off of the second transistor T2. When the second transistor T2 is turned on, the second light control circuit 202 can control the LED to emit light according to the voltage of the second terminal of the second transistor T2.

[0190] The second reference signal Sweep2 is output to the second capacitor C2 for adjusting the voltage at the second end of the second transistor T2, ie, the input end of the second light emitting control circuit 202, after the second transistor T2 is turned off, so that the second light emitting control circuit 202 controls the LED to stop emitting light.

[0191] An embodiment of the present application provides a control method for a pixel driving circuit. In the comparative light emission stage, the light emission control signal EM, the first reference signal Sweep1 and the second reference signal Sweep2 are controlled to control the on or off of corresponding transistors in the pixel driving circuit 20 to achieve driving of the LED.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] The processor 1301 and the memory 1302 may be connected via a bus 1303. The bus 1303 may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus 1303 may be an address bus, a data bus, a control bus, etc. For ease of representation, the bus 1303 in the drawings of the present application is not limited to only one bus or one type of bus.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] 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, pixel driving circuit; The display panel is used to display image information, and includes a plurality of pixels, wherein the pixels include at least one LED; The pixel driving circuit is used to drive pixels in the display panel, and includes: A first light emitting control circuit comprises a first transistor and a second transistor, wherein the control end of the first transistor is used to receive a light emitting control signal, the first end is used to receive a first voltage signal VGH, and the second end is connected to the first end of the second transistor; a first capacitor, one end of which is used to receive a first reference signal, and the other end of which is connected to the control end of the second transistor; A second capacitor, one end of which is used to receive a second reference signal, and the other end of which is connected to the second end of the second transistor; a second light emitting control circuit, having an input end connected to the second end of the second transistor and an output end connected to the LED, and configured to control the LED according to a signal generated by the second end of the second transistor; Among them, the light-emitting control signal, the first reference signal and the second reference signal are all periodic signals, and the period at least includes a comparative light-emitting stage; in the comparative light-emitting stage, the level of the light-emitting control signal is the level for controlling the conduction of the first transistor, and the first reference signal and the second reference signal are both linearly changing ramp signals.

2. The display device according to claim 1, characterized in that The second light emitting control circuit comprises: a third transistor, a fourth transistor, a fifth transistor and a third capacitor; The control end of the third transistor is connected to the second end of the second transistor, the first end of the third transistor is used to receive a PAMD signal, the PAMD signal is a voltage value when the LED emits the highest brightness, and the second end of the third transistor is respectively connected to the control end of the fourth transistor and one end of the third capacitor; The control end of the fifth transistor is used to receive the light emitting control signal, the first end is used to receive the second voltage signal VDD, and the second end is connected to the first end of the fourth transistor; the second end of the fourth transistor is connected to one end of the LED; the other end of the LED is used to receive the light emitting control signal; The other end of the third capacitor is used to receive a third reference signal, which is a periodic signal. The period at least includes a comparison light-emitting stage. In the comparison light-emitting stage, the third reference signal is a ramp signal that changes linearly synchronously with the first reference signal and the second reference signal.

3. The display device according to claim 2, characterized in that Also includes: a sixth transistor and a seventh transistor; The control end of the sixth transistor is used to receive a row scanning signal, and the other two ends are respectively connected to the control end of the second transistor and the second end of the second transistor to perform threshold compensation on the second transistor; The control end of the seventh transistor is used to receive the row scanning signal, the first end is used to receive the PWMD signal, and the second end is connected to the first end of the second transistor; The PWMD signal is a voltage value that changes according to the brightness of the LED; the row scan signal is a periodic signal, and the period at least includes a data input stage and a comparison light-emitting stage, and the data input stage is before the comparison light-emitting stage; in the data input stage and the comparison light-emitting stage, the level of the row scan signal is different; In the comparison light-emitting stage, the level of the row scanning signal is different from the level of the light-emitting control signal.

4. The display device according to claim 3, characterized in that Also included: an eighth transistor; The control end of the eighth transistor is used to receive a reset signal, the first end is used to receive a reference voltage signal, and the second end is connected to the control end of the second transistor; Among them, the reset signal is a periodic signal, and the period at least includes a reset stage, a data input stage and a comparison and light-emitting stage. The reset stage is before the data input stage, and the data input stage is before the comparison and light-emitting stage; in the data input stage and the comparison and light-emitting stage, the level of the reset signal remains consistent and is different from the level in the reset stage; in the comparison and light-emitting stage, the level of the reset signal is consistent with the level of the row scanning signal.

5. The display device according to claim 4, characterized in that The first reference signal, the second reference signal, the third reference signal and the light emitting control signal also include a reset phase and a data input phase within the period, and the reset phase is located before the data input phase; The level of the light emitting control signal in the reset stage and the data input stage is consistent, and is different from the level in the comparison light emitting stage; The level of the first reference signal in the reset stage is consistent with that in the data input stage, and is consistent with the level of the light emitting control signal in the reset stage; The level of the second reference signal in the reset phase and the data input phase is consistent, and is different from the level of the first reference signal in the reset phase; The level of the third reference signal in the reset phase and the data input phase is consistent, and is consistent with the level of the second reference signal in the reset phase; The row scanning signal also includes a reset phase in the cycle. The reset phase is located before the data input phase, and the level is consistent with the level of the comparison light-emitting phase.

6. The display device according to claim 4, characterized in that The transistors among the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the sixth transistor, the seventh transistor and the eighth transistor 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: In the comparison light-emitting stage, the light-emitting control signal is received through the control end of the first transistor, the first end receives the first voltage signal VGH, the first transistor is turned on to turn on the second transistor, and the second light-emitting control circuit controls the LED to emit light according to the signal generated by the second end of the second transistor; Receiving a linearly changing first reference signal through one end of the first capacitor, so that the voltage of the second transistor control end at the other end of the first capacitor changes, and the second transistor is turned off; A linearly changing second reference signal is received through one end of the second capacitor to change the voltage of the second end of the second transistor at the other end of the second capacitor, and the second light-emitting control circuit controls the LED to stop emitting light according to the signal currently generated by the second end of the second transistor.

8. The display device according to claim 7, characterized in that The second light emitting control circuit is configured as follows: In the comparison light-emitting stage, the light-emitting control signal is received through the control terminal of the fifth transistor, and the first terminal receives the second voltage signal VDD, and the fifth transistor is turned on to set the voltage of the first terminal of the fourth transistor to VDD; When the second transistor is turned on, the control terminal of the third transistor receives the signal generated by the second terminal, and the first terminal receives the PAMD signal, and the third transistor is turned on to turn on the fourth transistor, thereby controlling the LED to emit light; A linearly changing second reference signal is received through one end of the second capacitor, so that the voltage of the third transistor control terminal at the other end of the second capacitor changes, and the third transistor is turned off; Receiving a linearly changing third reference signal through one end of the third capacitor, so that the voltage of the fourth transistor control end at the other end of the third capacitor changes, and the fourth transistor is turned off to control the LED to stop emitting light; The third reference signal is a ramp signal that changes linearly in synchronization with the first reference signal and the second reference signal.

9. The display device according to claim 8, characterized in that The pixel driving circuit is further configured as follows: In the data input stage, the control end of the seventh transistor receives the row scan signal, the first end receives the PWMD signal, and the seventh transistor is turned on to turn on the second transistor; Receiving a row scan signal through a control terminal of a sixth transistor, the sixth transistor is turned on to perform threshold compensation on the second transistor; Among them, the PWMD signal is a voltage value that changes according to the luminous brightness of the LED; the row scan signal is a periodic signal, and the period at least includes a data input stage and a comparison luminous stage, and the data input stage is before the comparison luminous stage; in the data input stage and the comparison luminous stage, the level of the row scan signal is different; in the comparison luminous stage, the level of the row scan signal is different from that of the luminous control signal.

10. A pixel driving circuit, characterized in that: include: A first light emitting control circuit comprises a first transistor and a second transistor, wherein the control end of the first transistor is used to receive a light emitting control signal, the first end is used to receive a first voltage signal VGH, and the second end is connected to the first end of the second transistor; a first capacitor, one end of which is used to receive a first reference signal, and the other end of which is connected to the control end of the second transistor; A second capacitor, one end of which is used to receive a second reference signal, and the other end of which is connected to the second end of the second transistor; a second light emitting control circuit, having an input end connected to the second end of the second transistor and an output end connected to the LED, and configured to control the LED according to a signal generated by the second end of the second transistor; Wherein, the light-emitting control signal, the first reference signal and the second reference signal are all periodic signals, and the period at least includes a comparative light-emitting phase; In the comparison light-emitting stage, the level of the light-emitting control signal is a level for controlling the first transistor to be turned on, and the first reference signal and the second reference signal are both linearly changing ramp signals.

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