Method for compensating for switching afterimage of display screen, pixel driving circuit, and display substrate

Abstract

The embodiment of the present application provides a method for compensating for display screen switching afterimage, a pixel driving circuit, and a display substrate. The method includes: when it is necessary to compensate for the display screen switching afterimage, obtaining the pixel grayscale data of the switched screen; converting the pixel grayscale data of the switched screen into grayscale voltage data; obtaining the IC bias voltage, and determining the compensation bias voltage according to the grayscale voltage data and the IC bias voltage; using the compensation bias voltage as the data signal of the pixel to display the afterimage compensation frame; and displaying the switched screen according to the grayscale voltage data. Through the above method, the display screen switching afterimage of the OLED is improved.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and in particular, to a method for compensating for display screen switching afterimages, a pixel driving circuit, and a display substrate. Background Art

[0002] In the existing OLED (Organic Light-Emitting Diode) display effect, due to the hysteresis effect of thin-film transistors, when switching a long-time display screen, an afterimage phenomenon will occur. In order to improve the afterimage phenomenon, in the prior art, a method of stressing the TFT (Thin Film Transistor) and compensating the threshold voltage Vth before writing the data signal voltage is adopted to keep the difference between Vth2 - Vth1 consistent. However, affected by the OLED manufacturing process, it is still difficult to achieve the best effect. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide a method for compensating for display screen switching afterimages, a pixel driving circuit, and a display substrate to improve the afterimage of the OLED display screen switching. The specific technical solutions are as follows:

[0004] In a first aspect, the embodiments of the present application provide a method for compensating for display screen switching afterimages, the method including:

[0005] When it is necessary to compensate for the display screen switching afterimage, obtain the pixel gray-scale data of the switched screen;

[0006] Convert the pixel gray-scale data of the switched screen into gray-scale voltage data;

[0007] Obtain the IC bias voltage, and determine the compensation bias voltage according to the gray-scale voltage data and the IC bias voltage;

[0008] Use the compensation bias voltage as the data signal of the pixel to display an afterimage compensation frame;

[0009] Display the switched screen according to the gray-scale voltage data.

[0010] In a possible implementation manner, the method further includes:

[0011] Before the screen is switched, when it is detected that the number of frames of the pre-switched screen continues to exceed a preset frame number threshold, obtain the pixel gray-scale data of the pre-switched screen and the pixel gray-scale data of the switched screen;

[0012] Calculate the gray-scale difference between the pre-switched screen and the switched screen according to the pixel gray-scale data of the pre-switched screen and the pixel gray-scale data of the switched screen;

[0013] When the grayscale difference is not equal to 0, it is determined that display screen switching afterimage compensation needs to be performed.

[0014] In a possible implementation manner, the grayscale voltage data includes the grayscale voltages of each pixel;

[0015] Determining the compensation bias voltage according to the grayscale voltage data and the IC bias voltage includes:

[0016] For each pixel, according to the grayscale voltage of the pixel and the IC bias voltage, the pixel compensation bias voltage of the pixel is calculated by weighted summation, where the compensation bias voltage includes the pixel compensation bias voltages of each pixel.

[0017] In a possible implementation manner, for each pixel, according to the grayscale voltage of the pixel and the IC bias voltage, calculating the pixel compensation bias voltage of the pixel by weighted summation includes:

[0018] For the i-th pixel, according to the grayscale voltage of the i-th pixel and the IC bias voltage, the pixel compensation bias voltage of the i-th pixel is calculated by the following formula:

[0019] Vcomp i = Vbias * W + Voltage i

[0020] where Vcomp i is the pixel compensation bias voltage of the i-th pixel, Vbias is the IC bias voltage, Voltage i is the grayscale voltage of the i-th pixel, and W is a preset weight coefficient.

[0021] In a second aspect, an embodiment of the present application provides a pixel driving circuit, including:

[0022] A reset module, a compensation module, a scan control module, a data writing module, an anode potential control module, and a light-emitting device;

[0023] The reset module, the compensation module, the data writing module, and the anode potential control module are respectively connected to the scan control module, and the scan control module is connected to the light-emitting device;

[0024] The data writing module is controlled by a first gate control signal, and the compensation module is controlled by a second gate control signal, where the first gate control signal and the second gate control signal are different control signals.

[0025] In a possible implementation, the data writing module includes a fourth transistor, the compensation module includes a second transistor, and the scan control module includes a third transistor, a fifth transistor, a sixth transistor, and a capacitor;

[0026] The gate of the second transistor is connected to the second gate control signal. The first end of the second transistor is respectively connected to the second end of the third transistor and the first end of the sixth transistor. The second end of the second transistor is connected to the second end of the capacitor. The first end of the capacitor is connected to the power supply voltage terminal;

[0027] The gate of the third transistor is connected to the second end of the capacitor. The first end of the third transistor is respectively connected to the second end of the fourth transistor and the second end of the fifth transistor;

[0028] The gate of the fourth transistor is connected to the first gate control signal. The first end of the fourth transistor is connected to the data signal voltage terminal;

[0029] The gate of the fifth transistor is connected to the control signal terminal. The first end of the fifth transistor is connected to the power supply voltage terminal;

[0030] The gate of the sixth transistor is connected to the control signal terminal. The second end of the sixth transistor is connected to the first electrode of the light-emitting device.

[0031] In a possible implementation, the reset module includes a first transistor, and the anode potential control module includes a seventh transistor;

[0032] The gate of the first transistor is connected to the reset signal terminal. The first end of the first transistor is connected to the second end of the capacitor. The second end of the first transistor is connected to the reset signal input terminal;

[0033] The gate of the seventh transistor is connected to the first gate control signal. The first end of the seventh transistor is connected to the first electrode of the light-emitting device. The second end of the seventh transistor is connected to the reset signal input terminal.

[0034] In a third aspect, an embodiment of the present application provides a display substrate, including:

[0035] A first type of gate driving circuit, a second type of gate driving circuit, and the pixel driving circuit according to any one of the second aspects above;

[0036] The first type of gate driving circuit provides a first gate control signal for the pixel driving circuit. The second type of gate driving circuit provides a second gate control signal for the pixel driving circuit.

[0037] In a possible implementation, the first type of gate driving circuit includes n - level outputs, and the second type of gate driving circuit includes n - level outputs, where n is the number of pixel rows in the display substrate;

[0038] The first - level output of the first type of gate driving circuit is connected to the reset module of the pixel driving circuit in the first pixel row, for providing a reset signal;

[0039] The i - th level output of the first type of gate driving circuit is connected to the reset module of the pixel driving circuit in the (i - 1) - th pixel row, for providing a reset signal; the i - th level output of the first type of gate driving circuit is further connected to the data writing module of the pixel driving circuit in the i - th pixel row, for providing a first gate control signal; where 1 < i < n and i is an integer;

[0040] The n - th level output of the first type of gate driving circuit is connected to the data writing module of the pixel driving circuit in the n - th pixel row, for providing a first gate control signal;

[0041] The j - th level output of the second type of gate driving circuit is connected to the compensation module of the pixel driving circuit in the j - th pixel row, for providing a second gate control signal; where 1 ≤ j ≤ n and j is an integer.

[0042] In a fourth aspect, an embodiment of the present application provides a display, including the display substrate and a control chip as described in any one of the above - mentioned third aspects, where the control chip is configured to implement the method as described in any one of the above - mentioned first aspects during operation.

[0043] Advantages of the embodiments of the present application:

[0044] A display - screen switching afterimage compensation method, a pixel driving circuit, and a display substrate provided by an embodiment of the present application include: in a case where display - screen switching afterimage compensation is required, acquiring pixel gray - scale data of the switched - to screen; converting the pixel gray - scale data of the switched - to screen into gray - scale voltage data; acquiring an IC bias voltage, and determining a compensation bias voltage according to the gray - scale voltage data and the IC bias voltage; using the compensation bias voltage as a data signal of the pixel to display an afterimage compensation frame; and displaying the switched - to screen according to the gray - scale voltage data. After the data - signal voltage Vdata writes the gray - scale voltage data, when triggering afterimage compensation, a compensation frame is inserted, and a compensation bias voltage is applied to the thin - film transistor, so that the threshold voltage is negatively and uniformly compensated, thereby ensuring that after long - term display at different gray - scales of different screens, the display - screen switching afterimage of the OLED is improved.

[0045] Of course, when implementing any product or method of the present application, it is not necessarily required to simultaneously achieve all the above - mentioned advantages. Description of the Drawings

[0046] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other embodiments can also be obtained based on these drawings.

[0047] Figure 1 It is a schematic diagram showing picture distortion in the related art;

[0048] Figure 2 It is a schematic diagram showing the change of the operating point where the OLED TFT has a hysteresis effect in the related art;

[0049] Figure 3 It is a schematic diagram of the structure of the pixel driving circuit 7T1C in the related art;

[0050] Figure 4 It is a schematic diagram of the output waveform after the ghosting is improved in the related art;

[0051] Figure 5 It is the first flow schematic diagram of the display screen switching ghosting compensation method provided by the embodiment of the present application;

[0052] Figure 6a It is the second flow schematic diagram of the display screen switching ghosting compensation method provided by the embodiment of the present application;

[0053] Figure 6b It is a logic schematic diagram for switching while maintaining the screen;

[0054] Figure 7 It is the third flow schematic diagram of the display screen switching ghosting compensation method provided by the embodiment of the present application;

[0055] Figure 8 It is the fourth flow schematic diagram of the display screen switching ghosting compensation method provided by the embodiment of the present application;

[0056] Figure 9 It is the first structure schematic diagram of the pixel driving circuit provided by the embodiment of the present application;

[0057] Figure 10 It is the second structure schematic diagram of the pixel driving circuit provided by the embodiment of the present application;

[0058] Figure 11 It is the third structure schematic diagram of the pixel driving circuit provided by the embodiment of the present application;

[0059] Figure 12 It is the first structure schematic diagram of the display substrate provided by the embodiment of the present application;

[0060] Figure 13 The second structural schematic diagram of the display substrate provided by the embodiment of the present application;

[0061] Figure 14 The schematic diagram of the output waveform after the display screen switching afterimage compensation;

[0062] Figure 15 The schematic diagram of the working point change after the display screen switching afterimage compensation;

[0063] Figure 16 A structural schematic diagram of the control chip of the display provided by the embodiment of the present application. Specific embodiments

[0064] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art based on the present application belong to the scope of protection of the present application.

[0065] Since the OLED technology has advantages such as large viewing angle, low power consumption, high luminous efficiency, and low cost, it has been widely used in the display technology field. However, the OLED technology uses TFT (Thin Film Transistor) to drive pixels to emit light. Due to the hysteresis effect of TFT (under different gate voltages, the traps at the interface between the insulating layer and P-Si capture and release carriers, and the back-channel induced charges affect, resulting in a difference in current), as Figure 1 shown, when the black and white screen is lit for 10s and switched to the white screen with 48 gray levels (W48), afterimages appear. The original white area becomes darker and the black area becomes brighter, which is the afterimage phenomenon.

[0066] When switching from the white screen to the W48 display, the working point of the TFT moves in the direction of lower current, and the driving current of the W48 screen becomes smaller. When switching from the black screen to the W48, the working point of the TFT moves in the direction of larger current, and the driving current of the W48 screen becomes larger. It takes a period of time to recover, as Figure 2 shown. Among them, Vgs is the gate-source voltage of the TFT, and Ids is the drain-source current of the TFT.

[0067] The human eye can recognize the brightness and darkness differences of the corresponding black and white areas after switching from the black and white screen to the W48 screen, resulting in a reversal of the image quality effect. Therefore, for OLED products, after switching the screen after a long-time display, the switched screen needs to be distortion-free. During the display process, different gray levels of the screen should not cause a large difference in the driving current due to the hysteresis effect after a long-time display, resulting in a distorted display effect of the screen.

[0068] In the driving of an OLED module, in order to improve the afterimage phenomenon, a driving method is introduced in which stress compensation and threshold voltage Vth compensation are performed on the TFT before writing the data signal voltage Vdata. The circuit schematic diagram is as Figure 3 shown. It is a pixel driving circuit in the related art, which consists of 7 transistors and 1 storage capacitor, so it is simply referred to as a 7T1C structure. There are also many similar circuit structures such as 6T1C, 5T2C, 8T1C, 8T2C, 9T2C, etc. Among them, V DD is the power supply voltage, Vdata is the data signal voltage, Vg is the gate voltage of transistor T3, and Vs is the source voltage of transistor T3. When there are different gray levels in different frames, the TFT generally undergoes 1 - 3 times of stress to make Vth1 as unified as possible to the same reference voltage and remain in the positive bias, so as to keep the difference between Vth2 - Vth1 consistent. When writing a black frame, the current difference of Vth2 corresponding to the writing voltage of the TFT is reduced, thereby reducing the drain - source current Ids difference of the TFT (T3), achieving the purpose of weakening the afterimage. The schematic diagram of the output waveform is as Figure 4 shown. The relationship between Ids and the threshold voltage Vth is as follows:

[0069] Ids ∝ (Vgs - Vth) 2 ∝ (Vdata + Vth1 - VDD - Vth2) 2 ∝ ((VDD - Vdata)+(Vth2 - Vth1)) 2

[0070] However, in the actual debugging process, it is found that there are still differences and relatively large differences in Vth2 - Vth1 corresponding to different gray levels in different frames. To solve the above problems, the embodiments of the present application propose a method for compensating afterimage during display frame switching, a pixel driving circuit, and a display substrate.

[0071] Next, a method for compensating afterimage during display frame switching provided by the embodiments of the present application will be described in detail. Refer to Figure 5 , which includes the following steps:

[0072] Step S501, in the case where afterimage compensation for display frame switching is required, obtain the pixel gray - level data of the switched - to frame.

[0073] It can be determined whether afterimage compensation for display frame switching is required by calculating the gray - scale difference between the pixel gray - level data of the switched - from frame and the pixel gray - level data of the switched - to frame. The switched - to frame is the new frame to be displayed.

[0074] Step S502, convert the pixel gray - level data of the switched - to frame into gray - scale voltage data.

[0075] In one example, pixel gray-scale data can be converted into gray-scale voltage data through interpolation. The corresponding values of some points are set inside the driving chip, and the values between points are calculated according to a preset functional relationship. The preset functional relationship is Voltage = f(Graydata). Here, Voltage represents the gray-scale voltage data, Graydata represents the pixel gray-scale data, and the form of the functional relationship f can be linear, for example: y = a * x + b, or the form of the functional relationship f can be exponential, for example: y = x a Voltage is the final calculated result, and based on this result, a suitable compensation bias voltage will be found later. The logic of converting pixel gray-scale data into gray-scale voltage data is shown in Table 1 below:

[0076] Table 1

[0077] Graydata 1 Voltage 1 Graydata 2 Voltage 2 …… Graydata N Voltage N

[0078] Step S503: Obtain the IC bias voltage, and determine the compensation bias voltage according to the gray-scale voltage data and the IC bias voltage.

[0079] The IC bias voltage is the bias voltage set by the current driving chip. In one example, for each pixel of the switched-back picture, the gray-scale voltage data can be Voltage i , the IC bias voltage can be Vbias, and the compensation bias voltage Vcomp i can be Vcomp i = Vbias + Voltage i .

[0080] Step S504: Use the compensation bias voltage as the data signal of the pixel to display the residual image compensation frame.

[0081] After the data signal voltage Vdata writes the gray-scale voltage data, when the residual image compensation is triggered, a compensation frame is inserted. Again, the compensation bias voltage is used to make Vth2 negatively biased, improving the Vth2 of the TFT during long-term display of the OLED module, reducing the difference between Vth2 - Vth1, and after the action of the compensation bias voltage, the operating point moves down, reducing the Ids current of the TFT, thereby weakening the effect of picture quality flipping when the picture is switched.

[0082] Step S505: Display the switched-back picture according to the gray-scale voltage data.

[0083] In the embodiment of the present application, after the data signal voltage Vdata writes the gray-scale voltage data, when the residual image compensation is triggered, a compensation frame is inserted, and a compensation bias voltage is applied to the thin-film transistor, so that the threshold voltage is negatively compensated uniformly, thereby ensuring that after long-term display at different gray scales of different pictures, the residual image of the OLED display picture during switching is improved.

[0084] See Figure 6a , which is the second schematic flowchart of the display screen switching afterimage compensation method provided by the embodiment of the present application, and further includes the following steps:

[0085] Step S601, before the screen is switched, when it is detected that the number of frames of the pre-switching screen lasts exceeds a preset frame number threshold, obtain the pixel gray-scale data of the pre-switching screen and the pixel gray-scale data of the post-switching screen.

[0086] As Figure 6b shown, it is a logical schematic diagram for maintaining screen switching. When the MCU (Microcontroller Unit) inputs a frame of screen to the driving chip, it maintains a relatively long number of frames and keeps the screen frame count. The number of screen frames can be set according to actual needs as the preset frame number threshold. When it remains unchanged, the screen is in the long-term holding stage. When the MCU inputs a new frame of screen to the driving chip, the screen is switched. When the driving chip receives the screen to be displayed, it retains the pixel gray-scale data input by the MCU as the previous frame data. When the screen switches the data stream after maintaining a certain number of frames, it retains the input pixel gray-scale data as the new frame data.

[0087] Step S602, calculate the gray-scale difference between the pre-switching screen and the post-switching screen according to the pixel gray-scale data of the pre-switching screen and the pixel gray-scale data of the post-switching screen.

[0088] The gray-scale difference is obtained by taking the difference between the previous frame data and the new frame data. The screen switching logic is shown in Table 2 below:

[0089] Table 2

[0090] Before switching After switching Gray level difference Graydata 1 Graydata 1 SUM 1 Graydata 2 Graydata 2 SUM 2 …… …… …… Graydata N Graydata N SUM N

[0091] Step S603, when the gray-scale difference is not equal to 0, it is determined that display screen switching afterimage compensation needs to be performed.

[0092] When the gray-scale difference is not equal to 0, that is, it is detected that a new frame of screen is switched when the long-term held screen occurs, and it is determined that display screen switching afterimage compensation needs to be performed.

[0093] In the embodiment of the present application, it is determined whether display screen switching afterimage compensation needs to be performed through the gray-scale difference. When the gray-scale difference is not equal to 0, it is determined that display screen switching afterimage compensation needs to be performed.

[0094] See Figure 7 , which is the third schematic flowchart of the display screen switching afterimage compensation method provided by the embodiment of the present application, based on Figure 5Step S503 is refined. The grayscale voltage data includes the grayscale voltages of each pixel.

[0095] In step S701, for each pixel, based on the grayscale voltage of the pixel and the IC bias voltage, the pixel compensation bias voltage of the pixel is calculated by weighted summation. Among them, the compensation bias voltage includes the pixel compensation bias voltages of each pixel.

[0096] In the embodiment of the present application, for each pixel, based on the grayscale voltage of the pixel and the IC bias voltage, the pixel compensation bias voltage of the pixel is calculated by weighted summation.

[0097] See Figure 8 , which is the fourth process schematic diagram of the display screen switching afterimage compensation method provided by the embodiment of the present application. Based on Figure 7 Step S701 is refined, including the following steps:

[0098] In step S801, for the i-th pixel, based on the grayscale voltage of the i-th pixel and the IC bias voltage, the pixel compensation bias voltage of the i-th pixel is calculated through the following formula:

[0099] Vcomp i = Vbias * W + Voltage i

[0100] Among them, Vcomp i is the pixel compensation bias voltage of the i-th pixel, Vbias is the IC bias voltage, Voltage i is the grayscale voltage of the i-th pixel, and W is a preset weight coefficient.

[0101] The preset weight coefficient W can be set according to actual requirements. In one example, the preset weight coefficient W can be set to 1.

[0102] The correspondence table between the compensation bias voltage, the IC bias voltage, and the grayscale voltage data is shown in Table 3 below:

[0103] Table 3

[0104] Vbias Voltage 1 Vcomp 1 Vbias Voltage 2 Vcomp 2 …… …… …… Vbias Voltage N Vcomp N

[0105] Determine the appropriate compensation bias voltage Vcomp according to the grayscale voltage data Voltage.

[0106] In the embodiment of the present application, the pixel compensation bias voltage of the i-th pixel is calculated through the formula.

[0107] The embodiment of the present application also provides a pixel driving circuit 1. See Figure 9 , including:

[0108] A reset module 11, a compensation module 12, a scan control module 13, a data writing module 14, an anode potential control module 15, and a light-emitting device 16;

[0109] The reset module 11, the compensation module 12, the data writing module 14, and the anode potential control module 15 are respectively connected to the scan control module 13, and the scan control module 13 is connected to the light-emitting device 16;

[0110] The data writing module 14 is controlled by a first gate control signal Gate1, and the compensation module 12 is controlled by a second gate control signal Gate2. Wherein, the first gate control signal Gate1 and the second gate control signal Gate2 are different control signals.

[0111] Through the first gate control signal Gate1 and the second gate control signal Gate2, the compensation module 12 and the data writing module 14 are independently controlled. When the driving chip determines the corresponding parameters, according to the set parameters, corresponding voltage waveforms are dynamically output.

[0112] In the embodiment of the present application, the independent control of the compensation module and the data writing module is realized through the first gate control signal Gate1 and the second gate control signal Gate2.

[0113] In a possible implementation manner, referring to Figure 10 , the data writing module 14 includes a fourth transistor T4, the compensation module 12 includes a second transistor T2, and the scan control module 13 includes a third transistor T3, a fifth transistor T5, a sixth transistor T6, and a capacitor Cst;

[0114] The gate of the second transistor T2 is connected to the second gate control signal Gate2. The first end of the second transistor T2 is respectively connected to the second end of the third transistor T3 and the first end of the sixth transistor T6. The second end of the second transistor T2 is connected to the second end of the capacitor Cst; The first end of the capacitor Cst is connected to the power supply voltage terminal V DD is connected;

[0115] The gate of the third transistor T3 is connected to the second end of the capacitor Cst. The first end of the third transistor T3 is respectively connected to the second end of the fourth transistor T4 and the second end of the fifth transistor T5;

[0116] The gate of the fourth transistor T4 is connected to the first gate control signal Gate1. The first end of the fourth transistor T4 is connected to the data signal voltage terminal Vdata;

[0117] The gate of the fifth transistor T5 is connected to the control signal terminal EM, and the first end of the fifth transistor T5 is connected to the power supply voltage terminal V DD is connected;

[0118] The gate of the sixth transistor T6 is connected to the control signal terminal EM, and the second end of the sixth transistor T6 is connected to the first electrode of the light emitting device OLED.

[0119] The second electrode of the light emitting device OLED is connected to the low voltage terminal V SS is connected.

[0120] In the embodiment of the present application, the independent control of the second transistor T2 and the fourth transistor T4 is realized by the first gate control signal Gate1 and the second gate control signal Gate2.

[0121] In a possible implementation manner, referring to Figure 11 , the reset module 11 includes a first transistor T1, and the anode potential control module 15 includes a seventh transistor T7;

[0122] The gate of the first transistor T1 is connected to the reset signal terminal Reset, the first end of the first transistor T1 is connected to the second end of the capacitor Cst, and the second end of the first transistor T1 is connected to the reset signal input terminal Vinit;

[0123] The gate of the seventh transistor T7 is connected to the first gate control signal Gate1, the first end of the seventh transistor T7 is connected to the first electrode of the light emitting device OLED, and the second end of the seventh transistor T7 is connected to the reset signal input terminal Vinit.

[0124] In a possible implementation manner, each transistor is a P-type transistor.

[0125] The first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6, and the seventh transistor T7 are all P-type transistors;

[0126] The first end of the first transistor T1 is the source of the P-type transistor, and the second end of the first transistor T1 is the drain of the P-type transistor;

[0127] The first end of the second transistor T2 is the source of the P-type transistor, and the second end of the second transistor T2 is the drain of the P-type transistor;

[0128] The first end of the third transistor T3 is the source of the P-type transistor, and the second end of the third transistor T3 is the drain of the P-type transistor;

[0129] The first end of the fourth transistor T4 is the source of the P-type transistor, and the second end of the fourth transistor T4 is the drain of the P-type transistor;

[0130] The first end of the fifth transistor T5 is the source of the P-type transistor, and the second end of the fifth transistor T5 is the drain of the P-type transistor;

[0131] The first end of the sixth transistor T6 is the source of the P-type transistor, and the second end of the sixth transistor T6 is the drain of the P-type transistor;

[0132] The first end of the seventh transistor T7 is the source of the P-type transistor, and the second end of the seventh transistor T7 is the drain of the P-type transistor.

[0133] It can be understood that for any transistor in the circuit of the present application, the transistor can be an N-type transistor or a P-type transistor, and can be specifically selected according to the actual situation; the first end of the transistor is the source or the drain, and the second end of the transistor is the drain or the source corresponding to the first end. It can be understood that the transistor can be a P-type transistor or an N-type transistor, and can be specifically selected according to the actual situation, but the device connection mode of the circuit needs to be adjusted accordingly, and its replacement scheme is still within the protection scope of the present application.

[0134] It can be understood that the transistors used in the circuit of the present application can be MOS transistors (Metal-Oxide-Semiconductor Field-Effect Transistors), or TFT transistors (Thin Film Transistors) or other types of transistors, and can be specifically selected according to the actual situation. Its replacement scheme is still within the protection scope of the present application. For the connection mode of the TFT transistor or other types of transistors, reference can be made to the connection mode of the MOS transistor, which will not be elaborated here.

[0135] The embodiment of the present application also provides a display substrate, see Figure 12 , including:

[0136] A first type of gate driving circuit 2, a second type of gate driving circuit 3, and any one of the pixel driving circuits 1 in the above embodiments;

[0137] The first type of gate driving circuit 2 provides a first gate control signal Gate1 for the pixel driving circuit 1; the second type of gate driving circuit 3 provides a second gate control signal Gate2 for the pixel driving circuit 1.

[0138] In the embodiments of the present application, the first type of gate driving circuit and the second type of gate driving circuit are used to provide a first gate control signal Gate1 and a second gate control signal Gate2 for the pixel driving circuit.

[0139] In a possible implementation manner, the first type of gate driving circuit includes n-level outputs, and the second type of gate driving circuit includes n-level outputs, where n is the number of pixel rows in the display substrate;

[0140] The first-level output of the first type of gate driving circuit is connected to the reset module of the pixel driving circuit in the first pixel row for providing a reset signal;

[0141] The i-level output of the first type of gate driving circuit is connected to the reset module of the pixel driving circuit in the (i - 1)-th pixel row for providing a reset signal; the i-level output of the first type of gate driving circuit is further connected to the data writing module of the pixel driving circuit in the i-th pixel row for providing a first gate control signal; where 1 < i < n and i is an integer;

[0142] The n-level output of the first type of gate driving circuit is connected to the data writing module of the pixel driving circuit in the n-th pixel row for providing a first gate control signal;

[0143] The j-level output of the second type of gate driving circuit is connected to the compensation module of the pixel driving circuit in the j-th pixel row for providing a second gate control signal; where 1 ≤ j ≤ n and j is an integer.

[0144] See Figure 13 , in the OLED module driving circuit, to implement the addition of the second gate control signal Gate2, on the basis of the Gate&Reset GOA (Gate Driven on Array) and the EM GOA driving circuit, a bilateral Gate2 GOA driving circuit (the second type of gate driving circuit) is newly added. Gate&Reset GOA is equivalent to Gate1&ResetGOA (the first type of gate driving circuit). Gate2 GOA drives one level of Pixel (pixel) simultaneously on both sides, and outputs the second gate control signal Gate2, that is, provides Gate2 for one pixel row. The EM GOA bilateral drive keeps one level of GOA driving two rows of Pixel, and the EM GOA driving circuit is used to provide a scan control signal. The Gate1&Reset GOA bilateral drive connects the current-level Gate1 signal to the next-level Reset signal. Gate1_Rn only provides the Reset signal, and Gate1_Gn only provides the Gate1 signal.

[0145] In the embodiment of the present application, a first gate driving circuit provides a first gate control signal Gate1 and a reset signal for the pixel driving circuit; a second gate driving circuit provides a second gate control signal Gate2 for the pixel driving circuit.

[0146] See Figure 14 , which is a schematic diagram of the output waveform after the residual image compensation for the display screen switching. After the MCU inputs a frame of picture and keeps it for a long time, when it is detected that the picture changes when the MCU inputs a frame of picture again, the compensation frame for the residual image is triggered and inserted before the new input picture is refreshed. The number of inserted frames can be set according to actual needs. In one example, it can be set to 1. Under the new input picture, different compensation bias voltages Vcomp are output at different gray levels (Gray1 and Gray2). i , the preset number of compensation bias voltage pulses can be set according to requirements, and can be set to 1 or 3. Figure 14 It is shown as 3 in

[0147] See Figure 15 , which is a schematic diagram of the change of the working point after the residual image compensation for the display screen switching. After the data signal voltage Vdata writes the gray level voltage data Voltage i , the negative bias of Vth2 is achieved again through the compensation bias voltage Vcomp i to improve the positive bias of Vth2 of the TFT during the long-time display of the OLED module, reduce the difference between Vth2 and Vth1, and after the action of the compensation bias voltage, the working point moves down, reducing the Ids current of the TFT, thereby weakening the effect reversal of the picture quality during the picture switching, which is beneficial for the driving chip to select the optimal parameter combination when outputting different pictures to achieve the best display purpose.

[0148] The embodiment of the present application also provides a display, including the display substrate and the control chip described in any one of the above embodiments, and the control chip is used to implement the method for compensating the residual image during the display screen switching described in any one of the above embodiments when running.

[0149] The control chip can set the circuit structure as shown in Figure 16 , including a picture holding detection module, a conversion module, a gray level voltage data calculation module, an IC bias voltage setting module, a compensation bias voltage calculation module, a parameter combination determination module, and a voltage waveform output module.

[0150] Picture holding detection module: Realize the detection of holding the picture for a long time;

[0151] Conversion module: Realize the conversion of pixel gray level data to gray level voltage data;

[0152] Gray-scale voltage data calculation module: calculates the gray-scale voltage of each pixel in the current screen;

[0153] IC bias voltage setting module: sets the bias voltage constant inside the driving chip;

[0154] Compensation bias voltage calculation module: calculates the compensation bias voltage of each pixel in the current screen;

[0155] Parameter combination determination module: finds the compensation bias voltage parameter combination that matches the current screen;

[0156] Voltage waveform output module: outputs the corresponding voltage waveform according to the found compensation bias voltage parameters.

[0157] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0158] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and reference can be made to the relevant part of the method embodiment for the relevant content.

[0159] The above is only a preferred embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A method for compensating for afterimage in display screen switching, characterized in that, The method comprises: When it is necessary to perform image afterimage compensation for display screen switching, obtain pixel grayscale data of the screen after switching; Converting the pixel grayscale data of the switched picture into grayscale voltage data; Acquire an IC bias voltage, and determine a compensation bias voltage according to the grayscale voltage data and the IC bias voltage; Using the compensation bias voltage as a pixel data signal to display an afterimage compensation frame; The switched picture is displayed according to the grayscale voltage data.

2. The method according to claim 1, wherein The method further comprises: Before the picture is switched, when it is detected that the number of frames of the picture before the switching exceeds a preset frame number threshold, the pixel grayscale data of the picture before the switching and the pixel grayscale data of the picture after the switching are obtained; Calculating the grayscale difference between the picture before switching and the picture after switching according to the pixel grayscale data of the picture before switching and the pixel grayscale data of the picture after switching; When the grayscale difference is not equal to 0, it is determined that display screen switching afterimage compensation is required.

3. The method according to claim 1, characterized in that, The grayscale voltage data includes the grayscale voltage of each pixel; The step of determining the compensation bias voltage according to the grayscale voltage data and the IC bias voltage comprises: For each pixel, a pixel compensation bias voltage of the pixel is calculated by weighted summation according to the grayscale voltage of the pixel and the IC bias voltage, wherein the compensation bias voltage includes the pixel compensation bias voltage of each pixel.

4. The method according to claim 3, characterized in that, For each pixel, the pixel compensation bias voltage of the pixel is calculated by weighted summation according to the grayscale voltage of the pixel and the IC bias voltage, including: For the i-th pixel, according to the grayscale voltage of the i-th pixel and the IC bias voltage, the pixel compensation bias voltage of the i-th pixel is calculated by the following formula: Vcomp i = Vbias * W + Voltage i Among them, Vcomp i is the pixel compensation bias voltage of the i-th pixel, Vbias is the IC bias voltage, and Voltage i is the gray-scale voltage of the i-th pixel, and W is a preset weight coefficient.

5. A display, comprising a display substrate and a control chip, wherein the control chip is used to implement the method according to any one of claims 1 to 4 during operation.

6. The display according to claim 5, wherein The display substrate comprises: A first type gate driving circuit, a second type gate driving circuit and a pixel driving circuit; The first type of gate driving circuit provides a first gate control signal for the pixel driving circuit; the second type of gate driving circuit provides a second gate control signal for the pixel driving circuit.

7. The display according to claim 6, wherein The first type of gate driving circuit includes n-level outputs, and the second type of gate driving circuit includes n-level outputs, wherein n is the number of pixel rows in the display substrate; The first stage output of the first type of gate driving circuit is connected to the reset module of the pixel driving circuit in the first pixel row to provide a reset signal; The i-th level output of the first type of gate driving circuit is connected to the reset module of the pixel driving circuit in the i-1th pixel row, for providing a reset signal; the i-th level output of the first type of gate driving circuit is also connected to the data writing module of the pixel driving circuit in the i-th pixel row, for providing a first gate control signal; wherein 1<i<n, and i is an integer; The nth stage output of the first type of gate driving circuit is connected to the data writing module of the pixel driving circuit in the nth pixel row to provide a first gate control signal; The output of the j-th stage of the second type of gate driving circuit is connected to the compensation module of the pixel driving circuit in the j-th pixel row, and is used to provide a second gate control signal; where 1 ≤ j ≤ n, and j is an integer.

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