Liquid crystal display panel and display device

Abstract

The embodiment of the present application provides a liquid crystal display panel and a display device, wherein the liquid crystal display panel comprises a timing controller and an electric field control unit, the timing controller sends a timing signal to the liquid crystal display panel; the electric field control unit releases an electric field for driving liquid crystal deflection in the liquid crystal display panel in response to the reset signal of the timing controller changing from a first level to a second level. Through the above scheme, the internal electric field of the liquid crystal display panel is reduced during the reset of the timing controller, the potential difference between the two ends of the liquid crystal can be reduced, and the polarization phenomenon caused by the long-time non-deflection of the liquid crystal in the Demura process is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a liquid crystal display panel and a display device. BACKGROUND

[0002] After the screen production is completed, the light transmittance of the display panel is not uniform. In view of this situation, the display panel is compensated for brightness by the screen brightness compensation (Demura) technology. In the actual Demura process, in order to load Demura data, the timing controller stops outputting signals within 1 second. When the data signal and the scanning signal are both stopped outputting for 1 second, the electric field size of all pixel capacitances in the entire display panel is unchanged, which causes the liquid crystal to be polarized.

[0003] After the display panel returns to normal display, when the driving chip changes an electric field with the same size and opposite direction for each frame of the pixel, the liquid crystal is polarized, which causes the deflection angles of the liquid crystal in the two electric fields to be inconsistent, and further causes the brightness on the display panel to be inconsistent. When the brightness of the entire display panel changes every frame, a flicker visible to the naked eye is caused, which further affects the judgment of the Demua effect in the subsequent process flow. SUMMARY

[0004] Embodiments of the present application provide a liquid crystal display panel and a display device to solve the display panel flicker problem caused by liquid crystal polarization in the Demura process of related technologies.

[0005] To solve the above problems, an embodiment of the present application provides a liquid crystal display panel, comprising a timing controller and an electric field control unit. The timing controller is configured to send a timing signal to the liquid crystal display panel. The electric field control unit is configured to release an electric field for driving liquid crystal deflection in the liquid crystal display panel in response to a reset signal of the timing controller changing from a first level to a second level. The first level and the second level are different.

[0006] In an embodiment, the timing controller and the electric field control unit are respectively connected with a machine for performing brightness compensation on the liquid crystal display panel to receive a first control signal sent by the machine. The timing controller changes the reset signal from the first level to the second level according to the first control signal. The electric field control unit releases the electric field of the liquid crystal display panel according to the first control signal.

[0007] In an embodiment, the electric field control unit is further connected with the timing controller to perform a power-off operation on the timing controller and the electrodes driving the liquid crystal according to the first control signal respectively; wherein the power-off time length of the electrodes is equal to the power-off time length of the timing controller; and the liquid crystal display panel is further configured to perform the power-off according to the first control signal; wherein the power-off time length of the liquid crystal display panel is equal to the power-off time length of the timing controller.

[0008] In an embodiment, the electric field control unit comprises a discharge circuit configured to discharge the electric field according to a discharge signal; wherein the discharge signal of the discharge circuit is opposite to the first control signal.

[0009] In an embodiment, the discharge circuit comprises an inverter connected with the machine table, the inverter is configured to output the discharge signal after inverting the first control signal.

[0010] In an embodiment, the discharge circuit further comprises: a first transistor, a first electrode of the first transistor is connected to a first voltage through a first resistor, a second electrode of the first transistor is connected to a constant low voltage signal, a control electrode of the first transistor is connected to a first node through a second resistor; a second transistor, a first electrode of the second transistor is connected to a second voltage through a third resistor and connected to a third voltage through a fourth resistor, a second electrode of the second transistor is connected to the constant low voltage signal, a control electrode of the second transistor is connected to the first node through a fifth resistor; a third transistor, a first electrode of the third transistor is connected to a fourth voltage through a sixth resistor, a second electrode of the first transistor is connected to a constant low voltage signal, a control electrode of the first transistor is connected to the first node through a seventh resistor; a first capacitor, a first electrode of the first capacitor is connected to the first node and connected to a power management control signal (VLC) through an eighth resistor, a first electrode of the first capacitor is also connected to the constant low voltage signal through a ninth resistor, a second electrode of the first capacitor is connected to the constant low voltage signal; and a fourth transistor, a first electrode of the fourth transistor is connected to a constant high voltage signal (Vhigh) through R10, a second electrode of the fourth transistor is connected to the first node, a control electrode of the fourth transistor is connected to the first control signal (Vsignal); wherein the first transistor, the second transistor and the third transistor are NMOS transistors, the fourth transistor is a PMOS transistor, the fourth transistor constitutes the inverter, and the voltage value of the constant high voltage signal is the same as the high voltage value of the first control signal.

[0011] In an embodiment, the electric field control unit comprises a first pin for receiving the first control signal; the electric field control unit is further configured to: according to the first control signal, turn off the driving power supply of the electrode to realize the release of the electric field.

[0012] In an embodiment, the timing controller is further configured to: receive the first control signal and generate a second control signal according to the first control signal; the electric field control unit is further configured to: receive the second control signal and control the release of the electric field of the liquid crystal display panel according to the second control signal.

[0013] In an embodiment, the electric field control unit further comprises a second pin; the second pin is further configured to: receive the first control signal and the second control signal; the power management chip is further configured to: according to the first control signal, turn off the driving power supply of the electrode; and according to the second control signal, release the electric field.

[0014] In an embodiment, the electric field control unit is further configured to: receive the second control signal (IIC instruction) through a first communication protocol and release the electric field according to the second control signal.

[0015] In an embodiment, the timing controller is further configured to: according to the first control signal, control the liquid crystal display panel to display a preset gray scale picture; after the liquid crystal display panel displays the preset gray scale picture, the reset signal of the timing controller is changed from a second level to a first level.

[0016] In an embodiment, the timing controller is further configured to: receive the first control signal through a third pin or a second communication protocol.

[0017] In an embodiment, the electric field control unit is a power management chip of the display device.

[0018] Embodiments of the present application also provide a display device comprising the liquid crystal display panel of any of the above embodiments.

[0019] The embodiment of the present application provides a liquid crystal display panel and a display device, wherein the liquid crystal display panel comprises a timing controller electric field control unit, the timing controller sends a timing signal to the liquid crystal display panel; the electric field control unit releases the electric field for driving the liquid crystal deflection in the liquid crystal display panel in response to the reset signal of the timing controller changing from the first level to the second level. Through the above scheme, the internal electric field of the liquid crystal display panel is reduced during the reset of the timing controller, the potential difference between the two ends of the liquid crystal can be reduced, the polarization phenomenon caused by the long-time non-deflection of the liquid crystal in the Demura process is avoided, then the misjudgment of the Demura effect caused by the flicker in the subsequent detection process is avoided, and the screen brightness compensation effect can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A structural schematic diagram of a liquid crystal display panel provided in some embodiments of the present application is shown in the figure.

[0022] Figure 2 A discharge circuit structural schematic diagram provided in the related art is shown in the figure.

[0023] Figure 3 A discharge circuit structural schematic diagram provided in some embodiments of the present application is shown in the figure.

[0024] Figure 4 A structural schematic diagram of a display device provided in some embodiments of the present application is shown in the figure.

[0025] 10, display device; 100, liquid crystal display panel; 110, timing controller; 120, electric field control unit; 121, discharge circuit; 121a, inverter; 200, machine. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0027] It will be understood that, although the terms“first,”“second,” etc. can be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are only used to distinguish one component or signal from another.

[0028] After the production of the display panel, the display panel will have a non-uniform light transmittance. In the related art, a camera is used to capture the entire screen to detect the brightness data of the entire screen. Then, compensation data is made for the brightness of different areas of the display panel according to the brightness data, and the compensation data is stored in the program used by the display panel. In the use process, the timing controller of the display device will enhance or weaken the brightness of the non-uniform brightness area according to the compensation data in the program, so as to achieve the effect of uniform screen brightness.

[0029] The brightness compensation method in the related art generally includes the following steps:

[0030] S1: power on and light up the screen.

[0031] S2: the machine empties the part of the storage chip Flash that stores the brightness compensation (Demura) data to prevent the screen from not being in the original state. The machine is a brightness compensation machine used in the production process of the display panel.

[0032] S3: the machine pulls down the reset signal of the timing controller Tcon to turn off the timing controller, and pulls it up after one second to restart the timing controller, and then the timing controller will reload the program in the storage chip Flash. At this point, the initialization of the storage chip and the timing controller is completed.

[0033] S4: the machine starts the camera, collects the brightness data of the display panel at multiple gray scales, and generates compensation data.

[0034] S5: the machine writes the compensation data into the fixed position in the storage chip Flash.

[0035] S6: the machine pulls down the reset signal of the timing controller Tcon to turn off the timing controller, and pulls it up after one second to restart the timing controller, and then the timing controller will reload the program in the storage chip Flash.

[0036] S7: the timing controller Tcon uses the program with brightness compensation data to check the final brightness compensation effect of the screen display.

[0037] In the brightness compensation method, when the machine pulls down the reset signal of the timing controller, the whole timing controller stops outputting signals, including the data signal output to the driver IC and the gate drive signal output to the PMIC. When the timing controller stops outputting the data signal to the driver IC, the driver IC stops outputting new voltage to the pixel; when the timing controller stops outputting the gate drive signal to the PMIC, the capacitor switch of the pixel is closed.

[0038] It should be noted that when the liquid crystal is in a constant electric field for a long time, irreversible polarization will occur, and the deflection angle will always be biased in a certain direction. When the above two situations are superimposed, the electric field size of all pixel capacitors in the display panel will not change within one second when the reset signal of the timing controller is pulled down, and the liquid crystal will have polarization phenomenon within this one second.

[0039] In related technologies, in order to avoid the polarization of liquid crystal in general cases, a voltage with the same size and opposite direction is changed for each frame of the pixel in circuit driving, so as to avoid the polarization of liquid crystal and ensure the consistent light transmittance of the pixel in the two cases. However, for the polarization of liquid crystal caused by the above-mentioned brightness compensation process, when the driving provides a voltage with the same size and opposite direction for each frame of the pixel, the deflection angles of the liquid crystal in the two voltages are inconsistent, which will cause the brightness of the display panel to be inconsistent, that is, the brightness of the display panel will change once per frame, causing visible flicker.

[0040] In the case of flicker of the display panel, in step S7, if the brightness compensation effect is checked manually, it will be difficult to judge. Even if the brightness compensation effect is checked by a camera, since there is a shutter time when the camera takes a picture, when the display panel switches between high brightness and low brightness every frame, the shutter time of the camera will not be consistent with the switching rate of the high brightness frame and the low brightness frame, so that the proportion of the high brightness frame and the low brightness frame in the shutter time is not the same, and the brightness data collected at each gray scale is inconsistent with that in normal display. Therefore, the final brightness compensation effect will be deviated.

[0041] Figure 1 A structural diagram of a liquid crystal display panel provided in some embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the present application provides a liquid crystal display panel, which includes a timing controller and an electric field control unit, wherein the timing controller is configured to send timing signals to the liquid crystal display panel; and the electric field control unit is configured to release an electric field for driving liquid crystal deflection in the liquid crystal display panel in response to the reset signal of the timing controller changing from a first level to a second level. Figure 1

[0042] ​It should be noted that the first level and the second level are different, that is, the first level is the stop level of the timing controller, and the second level is the working level of the timing controller. In some more specific examples, the first level is a low level, and the second level is a high level. Based on the defects in the aforementioned brightness compensation process, the flicker of the display panel is within 1 second of the stop of the timing controller, and there is still an electric field in the liquid crystal display panel, which causes the polarization of the liquid crystal under the electric field. Therefore, in the display device of the present application, the electric field in the liquid crystal display panel is reduced as much as possible within the time period from when the reset signal of the timing controller is pulled low to when the reset signal is pulled high. It should be noted that the electric field in the liquid crystal display panel refers to the electric field applied in the liquid crystal layer for controlling the arrangement and direction of the liquid crystal molecules, and reducing the potential difference between the two ends of the liquid crystal can reduce the electric field in the liquid crystal display panel.

[0043] It should be understood that the electric field release involved in the embodiments of the present application includes releasing part of the electric field to reduce the potential difference between the two ends of the liquid crystal, and also includes completely releasing the electric field, for example, powering off the liquid crystal display panel, which can be achieved by turning off the power supply of the common electrode and the pixel electrode.

[0044] The timing controller, as the core control unit of the liquid crystal display panel, generates and sends accurate timing signals to the electric field control unit according to the input image signals and control instructions. For example, when displaying a static image, the timing controller sends timing signals at a fixed refresh rate to ensure stable image display; while displaying dynamic video, it dynamically adjusts the timing signals according to the frame rate of the video to achieve smooth visual effects.

[0045] When the timing controller receives the reset signal, for example, the signal changes from the first level (such as high level) to the second level (such as low level), or before the timing controller receives the reset signal, the electric field control unit releases the electric field in the liquid crystal display panel for driving the liquid crystal deflection. For example, when switching display content, the electric field control unit responds to the change of the reset signal and quickly releases the original electric field to prepare for the new liquid crystal deflection state.

[0046] The above scheme is to solve the problem of flicker of the liquid crystal display panel due to the previous process problems, such as the polarization phenomenon of the liquid crystal when the timing controller reset signal is pulled low by the machine, which causes screen flicker and other problems. Through the above scheme, the internal electric field of the liquid crystal display panel is reduced during the reset of the timing controller, which can reduce the potential difference between the two ends of the liquid crystal, avoid the polarization phenomenon caused by the long time without deflection of the liquid crystal in the Demura process, and further avoid the misjudgment of the Demura effect caused by the flicker in the subsequent detection process, which can effectively improve the screen brightness compensation effect.

[0047] In some embodiments, the timing controller and the electric field control unit are respectively connected to a machine for brightness compensation of the liquid crystal display panel to receive a first control signal sent by the machine; the timing controller changes the reset signal from a first level to a second level according to the first control signal; and the electric field control unit releases the electric field of the liquid crystal display panel according to the first control signal.

[0048] It should be noted that the first control signal can be a control signal sent by the machine during the brightness compensation process, or can be another signal synchronized with the machine signal. The timing controller and the electric field control unit are respectively connected to a machine for brightness compensation of the liquid crystal panel to receive a first control signal sent by the machine. The timing controller changes the reset signal from a first level to a second level according to the first control signal, and the electric field control unit also releases the electric field of the liquid crystal display panel according to the first control signal. In the working process of the liquid crystal display device, the machine plays a control and coordination role in the whole system. For example, in the Demura process in the screen production process, the machine needs to perform a series of operations to ensure the brightness uniformity of the screen. The machine here controls the timing controller and the electric field control unit by sending the first control signal. After the timing controller receives this signal, the level of the reset signal is changed, thereby triggering the electric field control unit to release the electric field. This design can effectively control the electric field in the liquid crystal panel in different working states (such as during brightness compensation and the like), avoid liquid crystal polarization and other adverse phenomena, and ensure the stability of the display effect.

[0049] In some embodiments, the liquid crystal display panel has a fast discharge function, and the electric field control unit is further connected to the timing controller to perform power-off operation on the timing controller and the electrode for driving the liquid crystal according to the first control signal; wherein the power-off time length of the electrode and the power-off time length of the timing controller are equal. In this embodiment, by changing the connection between the machine and the display device, the machine changes the reset signal of the timing controller from being pulled low for 1 second to powering off the entire panel for 1 second, so that the timing controller can reload the program in the storage chip flash while realizing fast discharge.

[0050] The electric field control unit is also connected to a timing controller, and according to the first control signal, the timing controller and the electrode driving liquid crystal are powered off respectively, and the power-off time of the electrode is equal to the power-off time of the timing controller. In the liquid crystal display device, the electrode and the timing controller both play a key role in the display control of the liquid crystal. For example, after the machine sends the first control signal, the electric field control unit simultaneously performs the power-off operation on the electrode and the timing controller. Such simultaneous and equal-time power-off operation is to ensure that the electric field state in the liquid crystal panel remains consistent during the entire operation process. If the power-off time of the electrode and the timing controller is not consistent, it may cause imbalance of the electric field state in the liquid crystal panel. For example, if the electrode is powered off first and the timing controller is powered off later, polarization of the liquid crystal may occur during this process, because the electric field environment of the liquid crystal changes unevenly during the asynchronous power-off process.

[0051] In some embodiments of the present application, the electric field control unit includes a discharge circuit for discharging the electric field according to a discharge signal; wherein the discharge signal of the discharge circuit is opposite to the first control signal.

[0052] In the electric field control system of the liquid crystal display device, the discharge circuit is a key part to release the electric field. For example, in the liquid crystal display panel, when it is necessary to release the electric field, due to the characteristics of the first control signal sent by the machine, a discharge signal opposite to the first control signal is needed to accurately control the operation of the discharge circuit. Assuming that the first control signal is high when it represents a certain operation state (such as not performing discharge operation), then the discharge signal opposite to it is low, at this time the discharge circuit starts to discharge the electric field according to the low-level discharge signal. The opposite design is to ensure that the discharge circuit can discharge at the right time, which matches the control logic of the entire display device. If the discharge signal is not opposite to the first control signal, the discharge circuit may discharge at the wrong time, which cannot effectively release the electric field, and thus cannot avoid the problem of liquid crystal polarization, affecting the normal effect of liquid crystal display.

[0053] When the power supply is less than 75%, the liquid crystal display panel is discharged. Figure 2 is a schematic diagram of a discharge circuit structure provided in the related art. In some embodiments, the discharge circuit refers to Figure 2 As shown, it includes a first transistor Q1, a second transistor Q2, a third transistor Q3 and a first capacitor C1.

[0054] The first electrode of the first transistor Q1 is connected to the first voltage VCC1 through the first resistor R1, the second electrode of the first transistor Q1 is connected to a constant low potential signal, and the control electrode of the first transistor Q1 is connected to the first node A through the second resistor R2; wherein the constant low potential signal can be a ground signal.

[0055] The first electrode of the second transistor Q2 is connected to the second voltage VCC2 through the third resistor R3 and to the third voltage VCC3 through the fourth resistor R4, the second electrode of the second transistor Q2 is connected to a constant low potential signal, and the control electrode of the second transistor Q2 is connected to the first node A through the fifth resistor R5.

[0056] The first electrode of the third transistor Q3 is connected to the fourth voltage VCC4 through the sixth resistor R6, the second electrode of the first transistor Q1 is connected to a constant low potential signal, and the control electrode of the first transistor Q1 is connected to the first node A through the seventh resistor R7. It should be noted that VCC1, VCC2, VCC3 and VCC4 are all power supply voltages in the display device, which are used to provide necessary power for the driving circuit, logic circuit, backlight system and control chip in the display device.

[0057] The first electrode of the first capacitor C1 is connected to the first node A and connected to the power management control signal (VLC) through the eighth resistor R8, and the first electrode of the first capacitor C1 is also connected to a constant low potential signal through the ninth resistor R9, and the second electrode of the first capacitor C1 is connected to a constant low potential signal.

[0058] When the power supply of the entire display panel is detected to be less than 75%, the power management control signal (VLC) is pulled high, and in addition to being connected to the discharging circuit, the power management control signal also controls the entire liquid crystal display panel. When the power management control signal is pulled high, the liquid crystal display panel quickly releases the charge in the pixel capacitor and dissipates the electric field therein. At the same time, the power management control signal is divided by resistors, which turns on the first transistor Q1, the second transistor Q2 and the third transistor Q3, and quickly releases the charge of VCC1, VCC2, VCC3 and VCC4 to ground through resistors. In the related art, since the control signal of the machine is from high to low, in this embodiment, the machine also needs to be modified. By changing the connection between the machine and the display device, the machine changes the reset signal of the timing controller from pulling low for 1 second to powering off the entire panel for 1 second. Through the aforementioned discharging circuit, the program in the storage chip flash can be quickly discharged and reloaded at the same time.

[0059] In some other embodiments, if the machine is not modified, the aforementioned discharging circuit needs to be improved, so that the first control signal of the machine is connected to the discharging circuit. The discharging circuit includes an inverter connected to the machine, which inverts the first control signal and outputs a discharging signal. Figure 3 A structure diagram of a discharging circuit provided in some embodiments of the present application is shown in FIG. 8. Figure 3 As shown in FIG. 8, compared with the discharging circuit in the aforementioned embodiment, the discharging circuit in this embodiment further includes a fourth transistor Q4 for forming an inverter.

[0060] The first electrode of the fourth transistor Q4 is connected to a constant high potential signal V HIGH , the second electrode of the fourth transistor Q4 is connected to the first node, and the control electrode of the fourth transistor Q4 is connected to a first control signal V SIGNAL . In the embodiment, the first transistor Q1, the second transistor Q2, and the third transistor Q3 are NMOS transistors, the fourth transistor Q4 is a PMOS transistor, the first control signal V SIGNAL is a machine signal, the constant high potential signal V HIGH is a voltage signal equal to the voltage of the machine high level signal, and VIN is the power input of the entire circuit. When the first control signal V SIGNAL is pulled low, the fourth transistor Q4 is turned on, the constant high potential signal V HIGH is transmitted to the first transistor Q1 to turn on the first transistor Q1. The VIN is short-circuited to the ground through the first resistor R1, and the voltage begins to drop. When the voltage drops to below 75% of the original voltage value of the VIN, the panel discharge function of the power chip is triggered, and the entire panel is discharged.

[0061] It should be noted that, during the one second when the first control signal V SIGNAL is pulled low, the VIN is discharged to the ground through R1. A large resistance value of R1 is required to control the entire current. After the first control signal V SIGNAL is pulled high again, the Q4 is turned off, the Q1 is turned off, and the VIN returns to normal. The entire circuit is restarted, and the program is reloaded.

[0062] It should be further noted that the transistors used in the embodiment of the present application can be thin film transistors or field effect transistors or other devices with the same characteristics. Since the source and drain of the transistor used are symmetrical, the source and drain are not distinguished. In the embodiment of the present application, one of the electrodes is referred to as the first electrode, and the other electrode is referred to as the second electrode. In addition, the gate of the transistor is referred to as the control electrode. In addition, the transistors can be divided into N-type and P-type according to their characteristics. In the following embodiment, the N-type transistor is described. When the N-type transistor is used, the first electrode is the source of the N-type transistor, the second electrode is the drain of the N-type transistor, the gate is inputted with a high level, the source and drain are turned on, and the P-type is opposite. It can be envisaged that the P-type transistor can be used to achieve the same result without creative labor, and therefore it is also within the protection scope of the embodiment of the present application.

[0063] In some embodiments of the present application, the electric field control unit can be implemented by a power management chip. The following description takes the power management chip as an example. In a liquid crystal display device, the power management chip is of great significance as the electric field control unit. The power management chip is originally responsible for the management and distribution of power in the entire display device. For example, during the operation of the liquid crystal display panel, the power management chip controls the power supply of each part. When it is used as the electric field control unit, it can use its control ability of the power supply to realize the control of the electric field in the liquid crystal panel. For example, by controlling the on-off of the driving power supply of the electrode to release the electric field. This design of using the power management chip as the electric field control unit combines the electric field control and the power management function, simplifies the circuit structure, and improves the integration and control efficiency of the entire display device.

[0064] The power management chip also has a first pin for receiving a first control signal, and the power management chip is further configured to turn off the driving power supply of the liquid crystal display panel according to the first control signal and control the liquid crystal display panel to discharge.

[0065] In this embodiment, the first pin can be an enable pin (Enable PIN) of the power management chip, which can control the switching of the entire power management chip. Therefore, the fast discharge function of the liquid crystal display panel can be bound to the enable pin for separate control, rather than being limited to detecting the size of the VIN voltage. When the pin is detected to be started, the power management chip turns off all driving power supplies and waits for the pin to be turned off before restarting. In this case, the first control signal is directly connected to the pin. When the first control signal is pulled low, the power management chip turns off all driving power supplies and starts the fast discharge function. When the first control signal is pulled high, the entire circuit is powered on again, the timing controller reloads the program, and since the discharge has been performed, the electric field in the panel disappears, and the polarization effect on the liquid crystal disappears.

[0066] Of course, there are also some power management chips that cannot bind the fast discharge function of the display panel to the first pin. Therefore, in some embodiments of the present application, the timing controller is further configured to receive a first control signal and generate a second control signal according to the first control signal; and the power management chip is further configured to receive the second control signal and control the liquid crystal display panel to discharge according to the second control signal. On this basis, the power management chip further includes a second pin, the second pin is further configured to receive the first control signal and the second control signal, and the power management chip is further configured to turn off the driving power supply of the liquid crystal display panel according to the first control signal and control the liquid crystal display panel to discharge according to the second control signal.

[0067] In this embodiment, the first control signal is connected to the power management chip and the timing controller at the same time, and then the signal connected to the power management chip can be delayed through a delay circuit. When the first control signal is pulled low, the timing controller receives the signal and then sends a signal to the power management chip to start the fast discharge function alone. Then the first control signal is transmitted to the voltage switch of the power management chip to turn off all voltages. After the first control signal is turned off, the power management chip restarts all voltages and the timing controller is powered on to load the program. It should be noted that the fast discharge of the display panel is a momentary function and does not need to be controlled by the first control signal for a long time. Only the timing controller needs to turn off the power supply of the timing controller after sending the fast discharge instruction.

[0068] In some other embodiments of the present application, when the fast discharge function of the power management chip cannot be bound to the first pin, the power management chip can also be instructed to discharge fast and turn off all driving voltages through a protocol instruction, that is, the power management chip is also used to receive a second control signal through a first communication protocol and control the liquid crystal display panel to discharge according to the second control signal. Specifically, in this embodiment, the first communication protocol can be an IIC communication protocol between the timing controller and the power management chip. At this time, the first control signal is connected to the timing controller and the voltage switch pin of the power management chip, and the timing controller receives the first control signal earlier than the power management chip through a delay circuit or the like. After the timing controller receives the first control signal, the timing controller sends an IIC instruction to the power management chip to start the fast discharge function. Then the power management chip receives the first control signal again, turns off all driving voltages when the first control signal is pulled low, and turns on all driving voltages after the first control signal is pulled high again, so that the timing controller can load the program again.

[0069] In the foregoing embodiments, the electric field in the entire liquid crystal display panel is released in the reset stage of the timing controller. In some liquid crystal display panels, the electric field in the liquid crystal display panel cannot be released. Therefore, in some other embodiments of the present application, the timing controller is further configured to: control the liquid crystal display panel to display a preset gray scale picture according to the first control signal; and change the reset signal of the timing controller from the second level to the first level after the liquid crystal display panel displays the preset gray scale picture. In this embodiment, if the screen is in a bright state within one second after the reset of the timing controller, it indicates that the electric field in the liquid crystal display panel is relatively large, and the influence on the liquid crystal polarization is relatively large. If the picture of the liquid crystal display panel can be stabilized at the preset gray scale picture state, and the reset of the timing controller is started again, the electric field in the liquid crystal display panel is relatively small, and the influence on the liquid crystal polarization is relatively small. It should be noted that, according to the type of the liquid crystal display panel, the arrangement of the liquid crystal molecules is different. In some liquid crystal display panels, the preset gray scale picture can be a black picture.

[0070] On this basis, in some embodiments of the present application, the timing controller has a third pin for receiving the first control signal. The third pin can be a built-in self-test (BIST) pin of the timing controller. When the BIST pin receives a signal, the timing controller can only output a black picture of the liquid crystal display panel. In this case, the first control signal can be directly connected to the BIST pin and the reset pin of the timing controller. In some cases, because the potential change of the first control signal is fixed, if the first control signal does not correspond to the high and low potentials of the reset signal of the timing controller, the first control signal can be connected to the reset signal of the timing controller through an inverter. In this embodiment, the reset signal of the timing controller also needs to be delayed through a delay circuit, so that the BIST pin of the timing controller receives the first control signal first. After the timing controller sends an instruction to output a black picture to the liquid crystal display panel, the reset signal of the timing controller is connected to the first control signal, and then the timing controller is turned off. Within one second when the first control signal is pulled low, the liquid crystal display panel is in a black picture, and the electric field in the liquid crystal display panel is relatively small, and the influence on the liquid crystal polarization is also relatively small, so that the flicker phenomenon of the picture of the display panel is avoided.

[0071] In some other embodiments, if the timing controller does not have a BIST pin, a separate programmable pin can also be set, so that the output of the black picture of the timing controller and the reloading of the program in the storage chip flash are combined. When the timing controller receives the first control signal, the liquid crystal display panel is controlled to display a black picture first, and then the program in the flash is reloaded.

[0072] In addition, in some other embodiments, the timing controller can also receive the first control signal through the second communication protocol if the timing controller does not have a BIST pin or a programmable pin. It should be noted that in this embodiment, although the timing controller can not have a BIST pin, the timing controller has the basic function of self-detection, and therefore, the first control signal can be input into the picture signal of the timing controller, and when the timing controller receives an incorrect picture signal, the timing controller will automatically enter a self-detection picture, so that the liquid crystal display panel displays a black picture.

[0073] More specifically, the picture signal received by the timing controller has two types of point-to-point protocol and LVDS protocol. The point-to-point protocol generally has a handshake signal (a series of signal exchanges used to establish a connection, synchronize, and negotiate communication parameters before two devices or systems start communicating), and when the picture signal is a point-to-point protocol, the handshake signal is changed through the first control signal, so that the timing controller enters a self-detection state. When the picture signal is an LVDS protocol, since the clock of the LVDS signal is external, the external clock is pulled low through the machine signal, and after the timing controller cannot receive the clock signal, it will consider that the picture signal is incorrect, so as to enter a self-detection state, so that the liquid crystal display panel enters a black picture.

[0074] Figure 4 is a structural schematic diagram of a display device provided in some embodiments of the present application. Referring to Figure 4 It is shown that the embodiments of the present application also provide a display device 10, which includes the liquid crystal display panel 100 described in any of the above embodiments.

[0075] According to application scenarios, the display device can include consumer electronic display devices, industrial display devices, and medical display devices, etc. Among them, the consumer electronic display device can include a mobile phone screen, a television screen, a computer display, etc. The industrial display device can include an industrial control panel, an instrument display screen, etc. The medical display device can include a medical diagnostic display and an operating room display, etc.

[0076] In summary, although the present application has been disclosed as above with preferred embodiments, the above preferred embodiments are not intended to limit the present application, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application is defined by the scope of the claims.

Claims

1. A liquid crystal display panel, characterized by comprising: comprising a timing controller and an electric field control unit, the timing controller is configured to send a timing signal to the liquid crystal display panel; the electric field control unit is configured to release an electric field for driving liquid crystal deflection in the liquid crystal display panel in response to a reset signal of the timing controller changing from a first level to a second level; wherein the first level and the second level are different; wherein the timing controller and the electric field control unit are respectively connected to a machine for brightness compensation of the liquid crystal display panel to receive a first control signal sent by the machine; the timing controller changes the reset signal from the first level to the second level according to the first control signal; the electric field control unit releases the electric field of the liquid crystal display panel according to the first control signal; the electric field control unit comprises a discharge circuit for discharging the electric field according to a discharge signal; wherein the discharge signal of the discharge circuit is opposite to the first control signal; the discharge circuit comprises an inverter connected to the machine, and the inverter inverts the first control signal and outputs the discharge signal; the discharge circuit further comprises: a first transistor, a first electrode of the first transistor is connected to a first voltage through a first resistor, a second electrode of the first transistor is connected to a constant low voltage signal, and a control electrode of the first transistor is connected to a first node through a second resistor; a second transistor, a first electrode of the second transistor is connected to a second voltage through a third resistor and connected to a third voltage through a fourth resistor, a second electrode of the second transistor is connected to the constant low voltage signal, and a control electrode of the second transistor is connected to the first node through a fifth resistor; a third transistor, a first electrode of the third transistor is connected to a fourth voltage through a sixth resistor, a second electrode of the third transistor is connected to a constant low voltage signal, and a control electrode of the third transistor is connected to the first node through a seventh resistor; a first capacitor, a first electrode of the first capacitor is connected to the first node and connected to a power management control signal (VLC) through an eighth resistor, a first electrode of the first capacitor is also connected to the constant low voltage signal through a ninth resistor, and a second electrode of the first capacitor is connected to the constant low voltage signal; and a fourth transistor, a first electrode of the fourth transistor is connected to a constant high voltage signal (Vhigh) through R10, a second electrode of the fourth transistor is connected to the first node, and a control electrode of the fourth transistor is connected to the first control signal (Vsignal); wherein the first transistor, the second transistor and the third transistor are NMOS transistors, the fourth transistor is a PMOS transistor, the fourth transistor constitutes the inverter, and a voltage value of the constant high voltage signal is the same as a high voltage value of the first control signal.

2. The liquid crystal display panel of claim 1, wherein the electric field control unit is further connected to the timing controller to perform power-off operation on the timing controller and electrodes driving the liquid crystal respectively according to the first control signal. The power-off duration of the electrode is equal to the power-off duration of the timing controller.

3. The liquid crystal display panel of claim 2, wherein the electric field control unit comprises a first pin configured to receive the first control signal. The electric field control unit is further configured to turn off a driving power supply of the electrode according to the first control signal, so as to release the electric field.

4. The liquid crystal display panel of claim 2, wherein the timing controller is further configured to receive the first control signal and generate a second control signal according to the first control signal. The electric field control unit is further configured to receive the second control signal and control the electric field of the liquid crystal display panel to be released according to the second control signal. The electric field control unit further comprises a second pin. The second pin is further configured to receive the first control signal and the second control signal.

5. The liquid crystal display panel according to claim 4, wherein The electric field control unit is further configured to turn off the driving power supply of the electrode according to the first control signal and release the electric field according to the second control signal.

6. The liquid crystal display panel of claim 4, wherein the electric field control unit is further configured to receive the second control signal (IIC instruction) through a first communication protocol and release the electric field according to the second control signal. The timing controller is further configured to: control the liquid crystal display panel to display a preset gray scale picture according to the first control signal; and turn the reset signal of the timing controller from a second level to a first level after the liquid crystal display panel displays the preset gray scale picture.

7. The liquid crystal display panel according to any one of claims 1 to 6, wherein The timing controller is further configured to: receive the first control signal through a third pin or a second communication protocol. The electric field control unit is a power management chip of a display device.

8. The liquid crystal display panel according to claim 7, wherein The liquid crystal display panel of any one of claims 1 to 9. ​ 9. The liquid crystal display panel according to any one of claims 1 to 6, wherein ​ 10. A display device, characterized by comprising: ​

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