Driving method of pixel circuit and display panel

Abstract

The application discloses a driving method of a pixel circuit and a display panel. The driving method can shorten the display time of a frame in a low gray scale range, improve the display gray scale, improve the current flowing through a light emitting device, avoid the driving of a low gray scale voltage, improve the stability of light emitting brightness, and further improve the mottling phenomenon of uneven light and dark in a low gray scale. Meanwhile, the gamma value is used in the process of calling the second data signal in the low gray scale range, so that the cutting of the gamma curve in the low gray scale is smoother, a smoother gray scale brightness curve is brought, and the implementation difficulty of the gamma curve is reduced.

Description

Technical Field

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

[0002] In a display panel, there are usually multiple pixel circuits, which include light-emitting devices. During operation, the pulse amplitude modulation (PAM) driving method changes the brightness by changing the current flowing through the light-emitting device. Because the luminous efficiency of the light-emitting device is unstable and uneven under low current conditions, uneven brightness and dark spots will appear in the low grayscale under the pulse amplitude modulation driving method. Summary of the Invention

[0003] This application provides a pixel circuit driving method and a display panel to alleviate the technical problems of uneven brightness and darkness at low gray levels and the difficulty in achieving gamma curves.

[0004] In a first aspect, this application provides a driving method for a pixel circuit. The pixel circuit includes a driving transistor, a writing transistor, a reset transistor, a discharging transistor, a storage capacitor, and a light-emitting device. The driving transistor is connected in series between a positive power supply signal and a negative power supply signal. The light-emitting device is connected in series between the driving transistor and the negative power supply signal. A data signal is connected to the first terminal of the writing transistor, and a scan signal is connected to the gate of the writing transistor. The second terminal of the writing transistor is connected to the gate of the driving transistor, one end of the storage capacitor, and the first terminal of the discharging transistor. A discharge signal is connected to the second terminal of the discharging transistor, and a discharge control signal is connected to the gate of the discharging transistor. The other end of the storage capacitor is connected to the anode of the light-emitting device and the first terminal of the reset transistor. A reference voltage signal is connected to the second terminal of the reset transistor. The gate of the body tube is connected to a scanning signal; the driving method includes: dividing a frame into odd subframes and even subframes that alternate sequentially in time; configuring data signals including a first data signal and a second data signal; setting a discharge control signal to have a pulse in each odd subframe, and the scanning signal and the first data signal to have pulses synchronously in each odd subframe and each even subframe; acquiring the grayscale of the image to be displayed and the gamma value of the gamma curve used by the image to be displayed; when the grayscale of the image to be displayed is in a low grayscale range, calling the second data signal according to the gamma value, wherein the display time corresponding to the second data signal in a frame is less than the display time corresponding to the first data signal in a frame, and the display grayscale corresponding to the second data signal in a frame is greater than the display grayscale corresponding to the first data signal in a frame.

[0005] In some embodiments, when the grayscale of the image to be displayed is in a low grayscale range, the step of calling a second data signal according to the gamma value, wherein the display time of the second data signal in one frame is less than the display time of the first data signal in one frame, and the display grayscale of the second data signal in one frame is greater than the display grayscale of the first data signal in one frame, includes: setting the grayscale and gamma value of the image to be displayed to M and N, respectively; and the ratio of the display time of the second data signal in one frame to the display time of the first data signal in one frame to be 1 / X. N In this case, the display grayscale corresponding to the second data signal in one frame is M*X.

[0006] In some embodiments, the ratio of the display time of the second data signal in one frame to the display time of the first data signal in one frame is 1 / X. N In the case where the display grayscale corresponding to the second data signal in a frame is M*X, the steps include: setting the second data signal to have pulses in the corresponding odd-numbered subframes, wherein the number of pulses of the second data signal in a frame is less than the number of pulses of the first data signal in a frame; and setting the pulse width of the second data signal to be equal to the pulse width of the first data signal.

[0007] In some embodiments, the ratio of the display time of the second data signal in one frame to the display time of the first data signal in one frame is 1 / X. N In the case where the display grayscale corresponding to the second data signal in one frame is M*X, the step further includes: as the grayscale of the image to be displayed decreases, reducing the number of pulses of the second data signal in one frame; and as the number of pulses of the second data signal in one frame decreases, increasing the display grayscale corresponding to the second data signal in one frame.

[0008] In some embodiments, when the grayscale of the image to be displayed is in a low grayscale range, the step of calling a second data signal according to the gamma value, wherein the display time corresponding to the second data signal in one frame is less than the display time corresponding to the first data signal in one frame, and the display grayscale corresponding to the second data signal in one frame is greater than the display grayscale corresponding to the first data signal in one frame, includes: setting the low grayscale range to include a first low grayscale range and a second low grayscale range, wherein the first low grayscale range is higher than the second low grayscale range; setting the data signal to include a third data signal, wherein the display time corresponding to the third data signal in one frame is less than the display time corresponding to the second data signal in one frame, and the display grayscale corresponding to the third data signal in one frame is equal to the display grayscale corresponding to the second data signal in one frame; and when the grayscale of the image to be displayed is in the first low grayscale range, providing the second data signal to the first electrode of the writing transistor; or, when the grayscale of the image to be displayed is in the second low grayscale range, providing the third data signal to the first electrode of the writing transistor.

[0009] In some embodiments, the step of setting the data signal further includes a third data signal, wherein the display time corresponding to the third data signal in a frame is less than the display time corresponding to the second data signal in a frame, and the display grayscale corresponding to the third data signal in a frame is equal to the display grayscale corresponding to the second data signal in a frame includes: setting the second data signal and the third data signal to have pulses in the corresponding odd-numbered subframes, wherein the number of pulses of the third data signal in a frame is less than the number of pulses of the second data signal in a frame; and setting the pulse width of the third data signal to be equal to the pulse width of the second data signal.

[0010] In some embodiments, when the grayscale of the image to be displayed is in a low grayscale range, the step of calling a second data signal according to the gamma value, wherein the display time corresponding to the second data signal in one frame is less than the display time corresponding to the first data signal in one frame, and the display grayscale corresponding to the second data signal in one frame is greater than the display grayscale corresponding to the first data signal in one frame, further includes: setting the low grayscale range to include a third low grayscale range, wherein the third low grayscale range is lower than the second low grayscale range; setting the data signal to include a fourth data signal, wherein the display time corresponding to the fourth data signal in one frame is less than the display time corresponding to the third data signal in one frame, and the display grayscale corresponding to the fourth data signal in one frame is equal to the display grayscale corresponding to the third data signal in one frame; and when the grayscale of the image to be displayed is in the third low grayscale range, providing the fourth data signal to the first electrode of the writing transistor.

[0011] In some embodiments, the step of setting the data signal further includes a fourth data signal, wherein the display time of the fourth data signal in one frame is less than the display time of the third data signal in one frame, and the display grayscale of the fourth data signal in one frame is equal to the display grayscale of the third data signal in one frame includes: setting the third data signal and the fourth data signal to have pulses in the corresponding odd-numbered subframes, wherein the number of pulses of the fourth data signal in one frame is less than the number of pulses of the third data signal in one frame; and setting the pulse width of the fourth data signal to be equal to the pulse width of the third data signal.

[0012] In some embodiments, after the steps of obtaining the grayscale of the image to be displayed and the gamma value of the gamma curve used by the image to be displayed, the method further includes: calling the first data signal when the grayscale of the image to be displayed is in the high grayscale range.

[0013] Secondly, this application provides a display panel, which includes a grayscale recognition module. The grayscale recognition module is used to recognize the grayscale of the image to be displayed in order to determine whether the grayscale of the image to be displayed belongs to a low grayscale range or a high grayscale range. The display panel executes the driving method in at least one of the above embodiments according to the grayscale of the image to be displayed.

[0014] The pixel circuit driving method and display panel provided in this application divide a frame into odd-numbered subframes and even-numbered subframes that alternate sequentially in time, and configure data signals including a first data signal and a second data signal. The discharge control signal has a pulse in each odd-numbered subframe, and the scanning signal and the first data signal synchronously have pulses in both odd-numbered and even-numbered subframes. The method also acquires the grayscale of the image to be displayed and the gamma value of the gamma curve used by the image. Then, when the grayscale of the image to be displayed is in a low grayscale range, the second data signal is called according to the gamma value. The display time corresponding to the second data signal in one frame is less than the display time of the first data signal in one frame. The corresponding display time, and the display grayscale corresponding to the second data signal in one frame is greater than that corresponding to the first data signal in one frame, can shorten the display time of one frame and increase the display grayscale in the low grayscale range. This can increase the current flowing through the light-emitting device, thus avoiding or eliminating the driving of low grayscale voltage, improving the stability of light emission brightness, and thus improving the uneven brightness and dimming phenomenon in low grayscale. At the same time, since the gamma value is used in the process of calling the second data signal in the low grayscale range, the cutting of the gamma curve in the low grayscale is smoother, resulting in a smoother grayscale brightness curve, which helps to reduce the implementation difficulty of the gamma curve. Attached Figure Description

[0015] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0016] Figure 1 This is a schematic flowchart of a pixel circuit driving method provided in an embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the pixel circuit provided in an embodiment of this application.

[0018] Figure 3 for Figure 2 The timing diagram shows the driving method of the pixel circuit shown. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0021] In view of the aforementioned technical problems of uneven brightness at low gray levels and the difficulty in implementing gamma curves, this embodiment provides a pixel circuit driving method. Please refer to [link to relevant documentation]. Figures 1 to 3 ,like Figure 2 As shown, the pixel circuit includes at least one of a driving transistor T2, a writing transistor T1, a reset transistor T3, a discharging transistor T4, a storage capacitor Cst, and a light-emitting device D1. The driving transistor T2 is connected in series between the positive power supply signal VDD and the negative power supply signal VSS. The light-emitting device D1 is connected in series between the driving transistor T2 and the negative power supply signal VSS. The first terminal of the writing transistor T1 is connected to the data signal DS, and the gate of the writing transistor T1 is connected to the scan signal SCAN. The second terminal of the writing transistor T1 is connected to the gate of the driving transistor T2, one end of the storage capacitor Cst, and the first terminal of the discharging transistor T4. The second terminal of the discharging transistor T4 is connected to the discharge signal Vneg, and the gate of the discharging transistor T4 is connected to the discharge control signal DIS. The other end of the storage capacitor Cst is connected to the anode of the light-emitting device D1 and the first terminal of the reset transistor T3. The second terminal of the reset transistor T3 is connected to the reference voltage signal Vref, and the gate of the reset transistor T3 is connected to the scan signal SCAN.

[0022] It should be noted that the first terminal can be either the source or the drain, and the second terminal can be either the source or the drain. For example, for the same transistor, if the first terminal is the source, the second terminal is the drain; or, if the first terminal is the drain, the second terminal is the source.

[0023] The light-emitting device D1 can be an organic light-emitting diode, a micro light-emitting diode, a mini light-emitting diode, or a quantum dot light-emitting diode.

[0024] At least one of the driving transistor T2, writing transistor T1, reset transistor T3, and discharging transistor T4 can be either an N-channel thin-film transistor or a P-channel thin-film transistor. Preferably, the driving transistor T2, writing transistor T1, reset transistor T3, and discharging transistor T4 are all N-channel thin-film transistors, and more specifically, they can be N-channel oxide thin-film transistors, such as indium gallium zinc oxide thin-film transistors.

[0025] The above driving methods include, for example Figure 1 The following steps are shown:

[0026] Step S10: Divide a frame into odd-numbered subframes and even-numbered subframes that appear alternately in time.

[0027] Step S20: Configure the data signals, including the first data signal and the second data signal.

[0028] Step S30: Set the discharge control signal to have a pulse in each odd subframe, and the scan signal and the first data signal to have pulses in both odd and even subframes.

[0029] Step S40: Obtain the grayscale of the image to be displayed and the gamma value of the gamma curve used by the image to be displayed.

[0030] Step S50: When the grayscale of the image to be displayed is in the low grayscale range, the second data signal is called according to the gamma value. The display time of the second data signal in one frame is less than the display time of the first data signal in one frame, and the display grayscale of the second data signal in one frame is greater than the display grayscale of the first data signal in one frame.

[0031] It is understood that the pixel circuit driving method provided in this embodiment divides a frame into odd-numbered subframes and even-numbered subframes that alternate sequentially in time, and configures the data signal DS to include a first data signal DS1 and a second data signal DS2. The discharge control signal DIS is set to have pulses in each odd-numbered subframe, and the scan signal SCAN and the first data signal DS1 are synchronously pulsed in both odd-numbered and even-numbered subframes. The grayscale of the image to be displayed and the gamma value of the gamma curve used by the image to be displayed are obtained. Then, when the grayscale of the image to be displayed is in a low grayscale range, the second data signal DS2 is called according to the gamma value. The display time corresponding to the second data signal DS2 in one frame is less than that of the first data signal DS2. Based on the display time corresponding to signal DS1 in a frame, and since the display grayscale corresponding to the second data signal DS2 in a frame is greater than that corresponding to the first data signal DS1 in a frame, the display time of a frame can be shortened and the display grayscale can be increased in the low grayscale range. This can increase the current flowing through the light-emitting device D1, thus avoiding or eliminating the driving of low grayscale voltage, improving the stability of the light emission brightness, and thus improving the uneven brightness and dimming phenomenon in low grayscale. At the same time, since the gamma value is used in the process of calling the second data signal DS2 in the low grayscale range, the cutting of the gamma curve in the low grayscale can be smoother, resulting in a smoother grayscale brightness curve, which in turn helps to reduce the difficulty of implementing the gamma curve.

[0032] It should be noted that, such as Figure 3 As shown, odd-numbered subframes can be the subframe consisting of the first positive pulse and the first low level from left to right of the SCAN signal, or the subframe consisting of the third positive pulse and the third low level from left to right of the SCAN signal, or the subframe consisting of the fifth positive pulse and the fifth low level from left to right of the SCAN signal. Even-numbered subframes can be the subframe consisting of the second positive pulse and the second low level from left to right of the SCAN signal, or the subframe consisting of the fourth positive pulse and the fourth low level from left to right of the SCAN signal, or the subframe consisting of the sixth positive pulse and the sixth low level from left to right of the SCAN signal.

[0033] The gamma value can range from 1.8 to 2.5. Preferably, the gamma value is 2.2.

[0034] It is understandable that a positive pulse of the scan signal SCAN can turn on the write transistor T1 and reset the transistor T3, while a low level of the scan signal SCAN can turn off the write transistor T1 and reset the transistor T3.

[0035] The discharge signal Vneg can be lower than the gate potential of the driving transistor T2. For example, the discharge signal Vneg can be less than or equal to 0V, so that the gate charge of the driving transistor T2 can flow out through the discharge transistor T4. A positive pulse of the discharge control signal DIS can turn on the discharge transistor T4, and a low potential of the discharge control signal DIS can turn off the discharge transistor T4.

[0036] Specifically, within the same subframe, the time interval between the falling edge of the scan signal SCAN and the rising edge of the discharge control signal DIS can be... Figure 3 The values ​​t1, t2, t3, t4, t5, and t6 shown are used to control the emission time within a subframe. The rising edge of the discharge control signal DIS can be adjusted according to the required emission time to regulate the emission time in the corresponding subframe. This time interval can be the same or different for each subframe.

[0037] Since the first data signal DS1 has a pulse in each subframe, while the discharge control signal DIS has no pulse in each even-numbered subframe, t0 can be used to represent the emission time in even-numbered subframes driven by the first data signal DS1.

[0038] Thus, the total illumination time in the next frame driven by the first data signal DS1 is 6*t0+t1+t2+t3+t4+t5+t6. The total illumination time in the next frame driven by the second data signal DS2 is t1+t2+t3+t4+t5+t6. The total illumination time in the next frame driven by the third data signal DS3 is t1+t2+t5+t6. The total illumination time in the next frame driven by the fourth data signal DS4 is t1+t6.

[0039] The potential of the reference voltage signal Vref can control the anode potential of the light-emitting device D1 and initialize the source potential of the driving transistor T2 during the writing stage of the data signal DS, so as to control the anode potential of the light-emitting device D1 to be less than the turn-on voltage.

[0040] In one embodiment, when the grayscale of the image to be displayed is in a low grayscale range, the second data signal DS2 is called according to the gamma value. The display time of the second data signal DS2 in one frame is less than the display time of the first data signal DS1 in one frame, and the display grayscale of the second data signal DS2 in one frame is greater than the display grayscale of the first data signal DS1 in one frame. The steps include: setting the grayscale and gamma value of the image to be displayed to M and N, respectively; and setting the ratio of the display time of the second data signal DS2 in one frame to the display time of the first data signal DS1 in one frame to be 1 / X. NIn this case, the display grayscale corresponding to the second data signal DS2 in one frame is M*X.

[0041] It should be noted that in this embodiment, the low grayscale range can be greater than or equal to 0 but less than 128 grayscale levels, and the second data signal DS2 can also be the third data signal DS3 or the fourth data signal DS4.

[0042] In one embodiment, the ratio of the display time of the second data signal DS2 in one frame to the display time of the first data signal DS1 in one frame is 1 / X. N In the case where the display grayscale corresponding to the second data signal DS2 in a frame is M*X, the steps include: setting the second data signal DS2 to have pulses in the corresponding odd-numbered subframes, wherein the number of pulses of the second data signal DS2 in a frame is less than the number of pulses of the first data signal DS1 in a frame; and setting the pulse width of the second data signal DS2 to be equal to the pulse width of the first data signal DS1.

[0043] It should be noted that since the second data signal DS2 has no pulses in even-numbered subframes, there is no corresponding emission time in even-numbered subframes, such as t0. This ensures that the display time of the second data signal DS2 in one frame is less than the display time of the first data signal DS1 in one frame.

[0044] In one embodiment, the ratio of the display time of the second data signal DS2 in one frame to the display time of the first data signal DS1 in one frame is 1 / X. N In the case where the display grayscale corresponding to the second data signal DS2 in one frame is M*X, the step further includes: as the grayscale of the image to be displayed decreases, reducing the number of pulses of the second data signal DS2 in one frame; and as the number of pulses of the second data signal DS2 in one frame decreases, increasing the display grayscale corresponding to the second data signal DS2 in one frame.

[0045] It should be noted that the display grayscale corresponding to the second data signal DS2 in one frame can be the amplitude of the positive pulse of the second data signal DS2, i.e., the grayscale voltage.

[0046] In one embodiment, when the grayscale of the image to be displayed is in a low grayscale range, the step of calling the second data signal DS2 according to the gamma value, wherein the display time of the second data signal DS2 in one frame is less than the display time of the first data signal DS1 in one frame, and the display grayscale of the second data signal DS2 in one frame is greater than the display grayscale of the first data signal DS1 in one frame, includes: setting the low grayscale range to include a first low grayscale range and a second low grayscale range, wherein the first low grayscale range is higher than the second low grayscale range; setting the data signal DS to include a third data signal DS3, wherein the display time of the third data signal DS3 in one frame is less than the display time of the second data signal DS2 in one frame, and the display grayscale of the third data signal DS3 in one frame is equal to the display grayscale of the second data signal DS2 in one frame; and when the grayscale of the image to be displayed is in the first low grayscale range, providing the second data signal DS2 to the first electrode of the writing transistor T1; or, when the grayscale of the image to be displayed is in the second low grayscale range, providing the third data signal DS3 to the first electrode of the writing transistor T1.

[0047] It should be noted that in this embodiment, the low grayscale range is further divided into a first low grayscale range and a second low grayscale range. As the number of low grayscale ranges increases, the number of data signals DS corresponding to different low grayscale ranges also increases. This can improve the control accuracy of display time and display grayscale in different low grayscale levels.

[0048] In one embodiment, the step of setting the data signal DS further includes a third data signal DS3, wherein the display time of the third data signal DS3 in one frame is less than the display time of the second data signal DS2 in one frame, and the display grayscale of the third data signal DS3 in one frame is equal to the display grayscale of the second data signal DS2 in one frame includes: setting the second data signal DS2 and the third data signal DS3 to have pulses in the corresponding odd-numbered subframes, wherein the number of pulses of the third data signal DS3 in one frame is less than the number of pulses of the second data signal DS2 in one frame; and setting the pulse width of the third data signal DS3 to be equal to the pulse width of the second data signal DS2.

[0049] It should be noted that this embodiment further increases the number of data signals DS corresponding to the low grayscale range, namely the third data signal DS3. This is beneficial for dividing a larger number of different low grayscale ranges, which can improve the control accuracy of display time and display grayscale in different low grayscale ranges.

[0050] In one embodiment, when the grayscale of the image to be displayed is in a low grayscale range, the step of calling the second data signal DS2 according to the gamma value, wherein the display time corresponding to the second data signal DS2 in one frame is less than the display time corresponding to the first data signal DS1 in one frame, and the display grayscale corresponding to the second data signal DS2 in one frame is greater than the display grayscale corresponding to the first data signal DS1 in one frame, further includes: setting the low grayscale range to include a third low grayscale range, the third low grayscale range being lower than the second low grayscale range; setting the data signal DS to include a fourth data signal DS4, wherein the display time corresponding to the fourth data signal DS4 in one frame is less than the display time corresponding to the third data signal DS3 in one frame, and the display grayscale corresponding to the fourth data signal DS4 in one frame is equal to the display grayscale corresponding to the third data signal DS3 in one frame; and when the grayscale of the image to be displayed is in the third low grayscale range, providing the fourth data signal DS4 to the first electrode of the writing transistor T1.

[0051] It should be noted that in this embodiment, the low grayscale range is further divided into a first low grayscale range, a second low grayscale range, and a third low grayscale range. As the number of low grayscale ranges increases, the number of data signals DS corresponding to different low grayscale ranges also increases. This can further improve the control accuracy of display time and display grayscale in different low grayscale levels.

[0052] In one embodiment, the step of setting the data signal DS further includes a fourth data signal DS4, wherein the display time of the fourth data signal DS4 in one frame is less than the display time of the third data signal DS3 in one frame, and the display grayscale of the fourth data signal DS4 in one frame is equal to the display grayscale of the third data signal DS3 in one frame includes: setting the third data signal DS3 and the fourth data signal DS4 to have pulses in the corresponding odd-numbered subframes, wherein the number of pulses of the fourth data signal DS4 in one frame is less than the number of pulses of the third data signal DS3 in one frame; and setting the pulse width of the fourth data signal DS4 to be equal to the pulse width of the third data signal DS3.

[0053] It should be noted that this embodiment further increases the number of data signals DS corresponding to the low grayscale range, namely the fourth data signal DS4. This is beneficial for dividing a larger number of different low grayscale ranges, and can further improve the control accuracy of display time and display grayscale in different low grayscale ranges.

[0054] For example, the first low grayscale range can be greater than or equal to 64 grayscale levels and less than 128 grayscale levels. The second low grayscale range can be greater than or equal to 32 grayscale levels and less than 64 grayscale levels. The third low grayscale range can be greater than or equal to 0 grayscale levels and less than 32 grayscale levels. In other embodiments, the specific endpoint values ​​of different low grayscale ranges can also be redefined.

[0055] In one embodiment, after the steps of obtaining the grayscale of the image to be displayed and the gamma value of the gamma curve used by the image to be displayed, the method further includes: calling the first data signal DS1 when the grayscale of the image to be displayed is in the high grayscale range.

[0056] It should be noted that this embodiment can identify the grayscale of the image to be displayed and first determine whether it belongs to the low grayscale range or the high grayscale range. If it belongs to the low grayscale range, it can be further determined to belong to the first low grayscale range, the second low grayscale range, or the third low grayscale range.

[0057] The high grayscale range can be greater than or equal to 128 and less than or equal to 255 grayscale levels. In this embodiment, each grayscale range is exemplified by a total grayscale of 256. When the total grayscale changes, each grayscale range also needs to be adjusted accordingly. For example, the low grayscale range remains unchanged, while 128 to the total grayscale is taken as the high grayscale range.

[0058] like Figure 2 , Figure 3 As shown, in the high grayscale range, each grayscale level is driven by the voltage of the first data signal DS1 for PAM. In the low grayscale range, the voltage of the second data signal DS2, the third data signal DS3, or the fourth data signal DS4 is selected, that is, the emission time is reduced, and the high grayscale level segmented by the first data signal DS1 is used for emission.

[0059] For example, in a gamma curve or grayscale brightness curve (taking a gamma value of 2.2 as an example, but other gamma values ​​are also possible), in a gamma curve with a gamma value of 2.2 (Gamma2.2), when actually performing 16 grayscale illumination (display), the voltage of the fourth data signal DS4 can be used, and the display time is greatly reduced. When the designed time is reduced to about 1 / 97 (8 to the power of 2.2) of the original time (the display time corresponding to the first data signal DS1 in one frame), the voltage of 16*8=128 grayscale levels divided by the first data signal DS1 can be called.

[0060] In the grayscale brightness curve of Gamma2.2, when 32 grayscale emission levels are actually required, the voltage of the third data signal DS3 can be used to reduce the designed emission time to about 1 / 21 of the original time (4 to the power of 2.2). The voltage of 32*4=128 grayscale levels divided by the first data signal DS1 can be called.

[0061] In the grayscale brightness curve of Gamma2.2, when 64 grayscale levels of emission are actually to be performed, the voltage of the second data signal DS2 can be used to reduce the designed emission time to about 1 / 4.6 of the original time (2 to the power of 2). At this time, the voltage of 64*2=128 grayscale levels divided by the first data signal DS1 can be called.

[0062] The designed light emission time can be achieved by the size of t0 to t6 in the design timing sequence. This operation can make the light-emitting device D1 in the low grayscale region to a certain extent move away from the low current working region, that is, away from the region where the LED light emission is uneven, thus solving the problem of low grayscale pitting.

[0063] In one embodiment, this embodiment provides a display panel, which includes a grayscale recognition module. The grayscale recognition module is used to identify the grayscale of the image to be displayed in order to determine whether the grayscale of the image to be displayed belongs to a low grayscale range or a high grayscale range. The display panel executes the driving method in at least one of the above embodiments according to the grayscale of the image to be displayed.

[0064] It is understood that, since the display panel provided in this embodiment executes the driving method in at least one of the above embodiments, it can also divide a frame into odd-numbered subframes and even-numbered subframes that alternate sequentially in time, configure the data signal DS to include a first data signal DS1 and a second data signal DS2, and set the discharge control signal DIS to have a pulse in each odd-numbered subframe, and the scan signal SCAN and the first data signal DS1 to have pulses synchronously in each odd-numbered subframe and each even-numbered subframe, and obtain the grayscale of the image to be displayed and the gamma value of the gamma curve used by the image to be displayed, and then, when the grayscale of the image to be displayed is in the low grayscale range, call the second data signal DS2 according to the gamma value, and the second data signal DS2 corresponds to the grayscale value in one frame. The display time is less than the display time corresponding to the first data signal DS1 in one frame, and the display grayscale corresponding to the second data signal DS2 in one frame is greater than the display grayscale corresponding to the first data signal DS1 in one frame. This can shorten the display time of one frame and increase the display grayscale in the low grayscale range, and increase the current flowing through the light-emitting device D1. This avoids or eliminates the driving of low grayscale voltage, improves the stability of light emission brightness, and thus improves the uneven brightness and dimming phenomenon in low grayscale. At the same time, since the gamma value is used in the process of calling the second data signal DS2 in the low grayscale range, the cutting of the gamma curve in the low grayscale is smoother, which will bring a smoother grayscale brightness curve, thus helping to reduce the implementation difficulty of the gamma curve.

[0065] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0066] The driving method of the pixel circuit and the display panel provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A driving method for a pixel circuit, characterized in that, The pixel circuit includes a driving transistor, a writing transistor, a reset transistor, a discharging transistor, a storage capacitor, and a light-emitting device. The driving transistor is connected in series between a positive power supply signal and a negative power supply signal. The light-emitting device is connected in series between the driving transistor and the negative power supply signal. The first terminal of the writing transistor is connected to a data signal, and the gate of the writing transistor is connected to a scan signal. The second terminal of the writing transistor is connected to the gate of the driving transistor, one end of the storage capacitor, and the first terminal of the discharging transistor. The second terminal of the discharging transistor is connected to a discharge signal, and the gate of the discharging transistor is connected to a discharge control signal. The other end of the storage capacitor is connected to the anode of the light-emitting device and the first terminal of the reset transistor. The second terminal of the reset transistor is connected to a reference voltage signal, and the gate of the reset transistor is connected to the scan signal. The driving method includes: A frame is divided into odd-numbered subframes and even-numbered subframes that alternate sequentially in time; The configured data signal includes a first data signal and a second data signal; The discharge control signal is configured to have a pulse in each odd-numbered subframe, and the scan signal and the first data signal are synchronized to have pulses in both each odd-numbered subframe and each even-numbered subframe; Obtain the grayscale of the image to be displayed, and the gamma value of the gamma curve used by the image to be displayed; When the grayscale of the image to be displayed is in a low grayscale range, the second data signal is called according to the gamma value. The display time of the second data signal in one frame is less than the display time of the first data signal in one frame, and the display grayscale of the second data signal in one frame is greater than the display grayscale of the first data signal in one frame. The step of calling the second data signal according to the gamma value when the grayscale of the image to be displayed is in a low grayscale range, wherein the display time of the second data signal in one frame is less than the display time of the first data signal in one frame, and the display grayscale of the second data signal in one frame is greater than the display grayscale of the first data signal in one frame, includes: The grayscale and gamma value of the image to be displayed are set to M and N, respectively; The ratio of the display time of the second data signal in one frame to the display time of the first data signal in one frame is 1 / X. N In this case, the display grayscale corresponding to the second data signal in one frame is M. X.

2. The driving method according to claim 1, characterized in that, The ratio of the display time corresponding to the second data signal in one frame to the display time corresponding to the first data signal in one frame is 1 / X. N In this case, the display grayscale corresponding to the second data signal in one frame is M. The steps of X include: The second data signal is configured to have pulses in the corresponding odd-numbered subframes, and the number of pulses of the second data signal in a frame is less than the number of pulses of the first data signal in a frame; The pulse width of the second data signal is set to be equal to the pulse width of the first data signal.

3. The driving method according to claim 2, characterized in that, The ratio of the display time corresponding to the second data signal in one frame to the display time corresponding to the first data signal in one frame is 1 / X. N In this case, the display grayscale corresponding to the second data signal in one frame is M. Step X also includes: As the grayscale of the image to be displayed decreases, the number of pulses in the second data signal in one frame decreases; As the number of pulses in the second data signal decreases in a frame, the corresponding display grayscale of the second data signal in a frame increases.

4. The driving method according to claim 1, characterized in that, The step of calling the second data signal according to the gamma value when the grayscale of the image to be displayed is in a low grayscale range, wherein the display time of the second data signal in one frame is less than the display time of the first data signal in one frame, and the display grayscale of the second data signal in one frame is greater than the display grayscale of the first data signal in one frame, includes: The low grayscale range is set to include a first low grayscale range and a second low grayscale range, wherein the first low grayscale range is higher than the second low grayscale range. The data signal is further configured to include a third data signal, wherein the display time of the third data signal in one frame is less than the display time of the second data signal in one frame, and the display grayscale of the third data signal in one frame is equal to the display grayscale of the second data signal in one frame; When the grayscale of the image to be displayed is within the first low grayscale range, the second data signal is provided to the first electrode of the write transistor; or, when the grayscale of the image to be displayed is within the second low grayscale range, the third data signal is provided to the first electrode of the write transistor.

5. The driving method according to claim 4, characterized in that, The step of setting the data signal to include a third data signal, wherein the display time corresponding to the third data signal in one frame is less than the display time corresponding to the second data signal in one frame, and the display grayscale corresponding to the third data signal in one frame is equal to the display grayscale corresponding to the second data signal in one frame, includes: The second data signal and the third data signal are configured to have pulses in the corresponding odd-numbered subframes, wherein the number of pulses of the third data signal in a frame is less than the number of pulses of the second data signal in a frame; The pulse width of the third data signal is set to be equal to the pulse width of the second data signal.

6. The driving method according to claim 4, characterized in that, The step of calling the second data signal according to the gamma value when the grayscale of the image to be displayed is in a low grayscale range, wherein the display time of the second data signal in one frame is less than the display time of the first data signal in one frame, and the display grayscale of the second data signal in one frame is greater than the display grayscale of the first data signal in one frame, further includes: The low grayscale range is further defined by a third low grayscale range, which is lower than the second low grayscale range. The data signal is further configured to include a fourth data signal, wherein the display time of the fourth data signal in one frame is less than the display time of the third data signal in one frame, and the display grayscale of the fourth data signal in one frame is equal to the display grayscale of the third data signal in one frame. When the grayscale of the image to be displayed is within the third low grayscale range, the fourth data signal is provided to the first electrode of the write transistor.

7. The driving method according to claim 6, characterized in that, The step of setting the data signal further includes a fourth data signal, wherein the display time corresponding to the fourth data signal in one frame is less than the display time corresponding to the third data signal in one frame, and the display grayscale corresponding to the fourth data signal in one frame is equal to the display grayscale corresponding to the third data signal in one frame, includes: The third data signal and the fourth data signal are configured to have pulses in the corresponding odd-numbered subframes, and the number of pulses of the fourth data signal in a frame is less than the number of pulses of the third data signal in a frame; The pulse width of the fourth data signal is set to be equal to the pulse width of the third data signal.

8. The driving method according to any one of claims 1-7, characterized in that, After the steps of obtaining the grayscale of the image to be displayed and the gamma value of the gamma curve used by the image to be displayed, the method further includes: When the grayscale of the image to be displayed is in the high grayscale range, the first data signal is invoked.

9. A display panel, characterized in that, The display panel includes a grayscale recognition module, which is used to recognize the grayscale of the image to be displayed to determine whether the grayscale of the image to be displayed belongs to a low grayscale range or a high grayscale range; the display panel executes the driving method as described in any one of claims 1-8 according to the grayscale of the image to be displayed.

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