Pixel unit, driving circuit, display panel, display device and driving method

Abstract

According to the pixel unit, the driving circuit, the display panel, the display device and the driving method, the pixel unit comprises a first thin film transistor, a pixel electrode, a common electrode and a second thin film transistor, a source electrode of the second thin film transistor is electrically connected with the pixel electrode, and a drain electrode of the second thin film transistor is electrically connected with the common electrode, the grid electrode of the first thin film transistor is used for inputting a starting signal, and the source electrode of the first thin film transistor is used for inputting an overcharge voltage, so that the liquid crystal capacitor is charged, and the pixel electrode has the overcharge voltage; the grid electrode of the second thin film transistor is used for inputting a discharging signal to enable the liquid crystal capacitor to discharge and enable the pixel electrode to have working voltage, the overcharge voltage is larger than the working voltage, the voltage of the pixel electrode can exceed the working voltage when the starting signal is finished, the working voltage is achieved through the discharging process, and the charging speed of the liquid crystal capacitor is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid crystal panels, and in particular to a pixel unit, a driving circuit, a display panel, a display device and a driving method. Background Art

[0002] With the development of consumer electronic products, major display screen manufacturers are constantly innovating. As the size, resolution and refresh rate of display screens continue to increase, the time provided for charging the liquid crystal capacitor is getting shorter and shorter, and the voltage loss of charging the liquid crystal capacitor is getting larger and larger. There is a problem that the liquid crystal capacitor cannot be charged to the working voltage at the end of the current line scan. Summary of the invention

[0003] The object of the present invention is to provide a pixel unit, a driving circuit, a display panel, a display device and a driving method to solve the problem that the liquid crystal capacitor cannot be charged to the working voltage at the end of the current line scanning.

[0004] To achieve the purpose of the present invention, the present invention provides the following technical solutions: In a first aspect, the present invention provides a pixel unit, comprising: a first thin film transistor; a pixel electrode, electrically connected to the drain of the first thin film transistor; a common electrode, forming a liquid crystal capacitor with the pixel electrode; a second thin film transistor, the source of the second thin film transistor is electrically connected to the pixel electrode, and the drain of the second thin film transistor is electrically connected to the common electrode; wherein the gate of the first thin film transistor is used to input a start signal, the source of the first thin film transistor is used to input an overcharge voltage to charge the liquid crystal capacitor and to make the pixel electrode have an overcharge voltage; the gate of the second thin film transistor is used to input a discharge signal to discharge the liquid crystal capacitor and to make the pixel electrode have an operating voltage, and the overcharge voltage is greater than the operating voltage.

[0005] In a second aspect, the present invention further provides a driving circuit, comprising a scan line, a data line and a pixel unit described in any one of the embodiments of the first aspect, wherein the gate of the first thin film transistor is electrically connected to the scan line, and the source of the first thin film transistor is electrically connected to the data line.

[0006] In one embodiment, there are N+1 scan lines and M data lines, N is a positive integer, and M is a positive integer; there are NM pixel units, and the NM pixel units are arranged in an array, and the 1st to Nth scan lines are electrically connected to the gates of the M first thin film transistors, the 2nd to N+1st scan lines are electrically connected to the gates of the M second thin film transistors, and the M data lines are electrically connected to the sources of the N first thin film transistors; wherein the nth scan line is used to output the turn-on signal to the gate of the first thin film transistor on the nth row, the M data lines are used to output the overcharge voltage to the source of the first thin film transistor on the nth row, and the n+1th scan line is used to output the discharge signal to the gate of the second thin film transistor on the nth row, and n is a positive integer less than N+1.

[0007] In one embodiment, the driving circuit further includes a signal driving unit and N+1 gate driving units, the signal driving unit is electrically connected to the same end of the M data lines, the signal driving unit is used to output the overcharge voltage, the N+1 gate driving units are electrically connected to the same end of the N+1 scan lines in a one-to-one correspondence, and the gate driving unit is used to output the start signal.

[0008] In one implementation, the width-to-length ratio of the second thin film transistor gradually decreases from a direction where the data line is close to the signal driving unit to a direction where the data line is far away from the signal driving unit.

[0009] In a third aspect, the present invention further provides a display panel, comprising a backlight module and a driving circuit as described in any one of the embodiments of the second aspect, wherein the backlight module is arranged on a side of the pixel electrode facing away from the common electrode.

[0010] In a fourth aspect, the present invention further provides a display device, comprising a housing and a display panel according to any one of the embodiments of the third aspect, wherein the display panel is installed in the housing.

[0011] In a fifth aspect, the present invention further provides a driving method, which is applied to the driving circuit of any one of the embodiments of the second aspect, comprising: in a first time period, the scanning line outputs an on signal to the gate of the first thin film transistor, and the data line outputs an overcharge voltage to the source of the first thin film transistor to charge the liquid crystal capacitor and make the pixel electrode have the overcharge voltage; in a second time period, a discharge signal is output to the gate of the second thin film transistor to discharge the liquid crystal capacitor and make the pixel electrode have an operating voltage.

[0012] In one embodiment, the number of scan lines is N+1, the number of data lines is M, N is a positive integer, and M is a positive integer; the number of pixel units is NM, the NM pixel units are arranged in an array, the 1st to Nth scan lines are electrically connected to the gates of the M first thin film transistors, the 2nd to N+1st scan lines are electrically connected to the gates of the M second thin film transistors, and the M data lines are electrically connected to the sources of the N first thin film transistors; a driving cycle of the driving circuit sequentially passes through the 1st time period, ..., the nth time period, the n+1th time period, ..., the N+1th time period, wherein n is a small is a positive integer greater than or equal to N; in the nth time period, the nth scan line outputs the turn-on signal to the gate of the first thin film transistor on the nth row, and the M data lines output the overcharge voltage to the source of the first thin film transistor on the nth row, so as to charge the liquid crystal capacitor on the nth row and make the pixel electrode on the nth row have the overcharge voltage; in the n+1th time period, the n+1th scan line outputs the discharge signal to the gate of the second thin film transistor on the nth row, so as to discharge the liquid crystal capacitor on the nth row and make the pixel electrode on the nth row have the working voltage.

[0013] In one embodiment, the driving circuit further includes N+1 gate driving units, and the N+1 gate driving units are electrically connected to the same end of the N+1 scan lines in a one-to-one correspondence; in the nth time period, the nth gate driving unit outputs the start signal to the nth scan line; in the n+1th time period, the n+1th gate driving unit outputs the discharge signal to the n+1th scan line.

[0014] The pixel unit includes a first thin film transistor, a pixel electrode, a common electrode and a second thin film transistor, the source of the second thin film transistor is electrically connected to the pixel electrode, and the drain of the second thin film transistor is electrically connected to the common electrode, wherein the gate of the first thin film transistor is used to input an on signal, and the source of the first thin film transistor is used to input an overcharge voltage to charge the liquid crystal capacitor and make the pixel electrode have an overcharge voltage; the gate of the second thin film transistor is used to input a discharge signal to discharge the liquid crystal capacitor and make the pixel electrode have an operating voltage, and the overcharge voltage is greater than the operating voltage, so that the voltage of the pixel electrode can exceed the operating voltage when the on signal ends, and reach the operating voltage through the discharge process, thereby improving the charging speed of the liquid crystal capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 is a schematic diagram of a driving circuit of an embodiment; Figure 2 is a schematic diagram of a comparative driving circuit; Figure 3 is a schematic diagram of a display device according to an embodiment; Figure 4 is a scanning line potential diagram of a driving circuit of an embodiment; Figure 5 1 is a potential diagram of the pixel electrode of an embodiment and a comparative example.

[0017] Description of reference numerals: 1000-display device; 100-display panel; 10- driving circuit; P-pixel unit, T1-first thin film transistor, T2-second thin film transistor, C1-liquid crystal capacitor, C2-parasitic capacitor, GOA-gate driving unit, G-scan line, D-data line, VCOM-common power supply; 200-housing; T-driving cycle, t1-first period, t n - The nth period, t n+1 -n+1th period, t N - Nth period, t N+1 -N+1th period. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0020] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0021] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0022] Please refer to Figure 1 The present invention provides a pixel unit P, including a first thin film transistor T1, a pixel electrode, a common electrode and a second thin film transistor T2, the pixel electrode is electrically connected to the drain of the first thin film transistor T1, the common electrode and the pixel electrode form a liquid crystal capacitor C1, the source of the second thin film transistor T2 is electrically connected to the pixel electrode, and the drain of the second thin film transistor T2 is electrically connected to the common electrode, wherein the gate of the first thin film transistor T1 is used to input an on signal, the source of the first thin film transistor T1 is used to input an overcharge voltage to charge the liquid crystal capacitor C1 and make the pixel electrode have the overcharge voltage, the gate of the second thin film transistor T2 is used to input a discharge signal to discharge the liquid crystal capacitor C1 and make the pixel electrode have a working voltage, and the overcharge voltage is greater than the working voltage.

[0023] Optionally, the pixel electrode and the common electrode are arranged opposite to each other and at intervals, a liquid crystal (not shown) is arranged between the pixel electrode and the common electrode, the common electrode is electrically connected to a common power supply VCOM and has a common voltage, and when the pixel electrode is charged to an operating voltage, a potential difference is formed between the pixel electrode and the common electrode, so that the arrangement direction or physical state of the liquid crystal controls the amount of light passing through the liquid crystal light valve, thereby realizing different grayscale displays, and then realizing color display through the RGB filter.

[0024] Specifically, the gate of the first thin film transistor T1 inputs a start signal, so that the first thin film transistor T1 is turned on, the source of the first thin film transistor T1 inputs an overcharge voltage, and the overcharge voltage is input to the pixel electrode through the first thin film transistor T1, so that the voltage of the pixel electrode reaches the overcharge voltage. At this time, the common voltage of the common electrode is less than the overcharge voltage of the pixel electrode, and the liquid crystal capacitor C1 completes the overcharge process. The gate of the first thin film transistor T1 stops inputting a start signal, so that the first thin film transistor T1 is turned off, and the gate of the second thin film transistor T2 inputs a discharge signal, so that the second thin film transistor T2 is turned on, and the pixel electrode discharges to the common electrode through the second thin film transistor T2 to the working voltage.

[0025] Among them, since the time for inputting the discharge signal to the gate of the second thin film transistor T2 is constant, the width-to-length ratio of the second thin film transistor T2 is constant, that is, the carrier migration rate is constant, the second thin film transistor T2 of the present invention can be set with a preset width-to-length ratio to achieve that within the time when the discharge signal is input to the gate of the second thin film transistor T2, the pixel electrode outputs a preset voltage to the common electrode through the second thin film transistor T2 to reach the working voltage.

[0026] Optionally, the gate of the first thin film transistor T1 is used to be electrically connected to a scan line G, and the scan line G is used to output a start signal. Optionally, the source of the first thin film transistor T1 is used to be electrically connected to a data line D, and the data line D is used to output an overcharge voltage. Optionally, the gate of the second thin film transistor T2 can be electrically connected to another scan line G, so that the start signal output through the scan line G can be used as a discharge signal to turn on the second thin film transistor T2, so that the pixel electrode is discharged to the working voltage. Optionally, the gate of the second thin film transistor T2 can also be electrically connected to a control chip (not shown), and the control chip is used to output a discharge signal.

[0027] Please refer to Figure 2 , Figure 2 The figure shows a schematic diagram of a pixel unit P of a comparative example. In the comparative example, a start signal is input to the gate of the first thin film transistor T1, and a charging signal is input to the source of the first thin film transistor T1 to realize charging of the liquid crystal capacitor C1. However, due to factors such as resolution and refresh rate, the charging time of the liquid crystal capacitor C1 is relatively short. At the same time, due to factors such as display screen size and wiring resistance, there is a large voltage loss of the charging voltage. As a result, after the liquid crystal capacitor C1 is charged, the voltage of the pixel electrode is less than the working voltage, that is, the charging speed of the liquid crystal capacitor C1 is slow.

[0028] The pixel unit P is provided to include a first thin film transistor T1, a pixel electrode, a common electrode, and a second thin film transistor T2, wherein the source of the second thin film transistor T2 is electrically connected to the pixel electrode, and the drain of the second thin film transistor T2 is electrically connected to the common electrode, wherein the gate of the first thin film transistor T1 is used to input an on signal, and the source of the first thin film transistor T1 is used to input an overcharge voltage to charge the liquid crystal capacitor C1 and to make the pixel electrode have an overcharge voltage; the gate of the second thin film transistor T2 is used to input a discharge signal to discharge the liquid crystal capacitor C1 and to make the pixel electrode have an operating voltage, and the overcharge voltage is greater than the operating voltage, so that the voltage of the pixel electrode can exceed the operating voltage when the on signal ends, and reach the operating voltage through the discharge process, thereby improving the charging speed of the liquid crystal capacitor C1.

[0029] Please refer to Figure 1The present invention further provides a driving circuit 10, comprising a scan line G, a data line D and a pixel unit P in an embodiment of the present invention, wherein a gate of a first thin film transistor T1 is electrically connected to the scan line G, and a source of the first thin film transistor T1 is electrically connected to the data line D. Optionally, a parasitic capacitor C2 is further formed between the data line D and the common electrode.

[0030] Among them, the scan line G is used to output a start signal to the gate of the first thin film transistor T1, so that the first thin film transistor T1 is turned on, and the data line D is used to output an overcharge voltage to the source of the first thin film transistor T1. The overcharge voltage is input to the pixel electrode through the first thin film transistor T1, so that the voltage of the pixel electrode reaches the overcharge voltage. At this time, the common voltage of the common electrode is less than the overcharge voltage of the pixel electrode, and the liquid crystal capacitor C1 completes the overcharge process. The scan line G stops inputting the start signal to the gate of the first thin film transistor T1, so that the first thin film transistor T1 is turned off, and the gate of the second thin film transistor T2 inputs a discharge signal, so that the second thin film transistor T2 is turned on, and the pixel electrode discharges to the common electrode through the second thin film transistor T2 to the working voltage.

[0031] The driving circuit 10 provided by the present invention realizes fast charging of the liquid crystal capacitor C1 by setting a scan line G, a data line D and a pixel unit P in an embodiment of the present invention, the gate of the first thin film transistor T1 is electrically connected to the scan line G, and the source of the first thin film transistor T1 is electrically connected to the data line D.

[0032] Please refer to Figure 1 , there are N+1 scanning lines G, there are M data lines D, N is a positive integer, M is a positive integer; there are NM pixel units P, the NM pixel units P are arranged in an array, the 1st to Nth scanning lines G 1、…、N The gates of the M first thin film transistors T1 are electrically connected to the 2nd to N+1st scanning lines G 2、…、N+1 Each of the M data lines D is electrically connected to the gate electrodes of the M second thin film transistors T2, and each of the M data lines D is electrically connected to the source electrodes of the N first thin film transistors T1; wherein the nth scanning line G n The M data lines D are used to output an on signal to the gate of the first thin film transistor T1 on the nth row, the M data lines D are used to output an overcharge voltage to the source of the first thin film transistor T1 on the nth row, and the n+1th scan line G n+1 It is used to output a discharge signal to the gate of the second thin film transistor T2 on the nth row, where n is a positive integer less than N+1.

[0033] Specifically, NM pixel units P are arranged in an array of N rows and M columns, wherein the first to Nth scanning lines G 1、…、N The gates of the first thin film transistors T1 are electrically connected to the M pixel units P, and the 2nd to N+1st scanning lines G 2、…、N+1The M data lines D are electrically connected to the gate electrodes of the second thin film transistors T2 of the M pixel units P, and the M data lines D are electrically connected to the source electrodes of the first thin film transistors T1 of the N pixel units P.

[0034] Among them, the N+1 scanning lines G are represented by horizontally arranged straight lines in the drawings of the specification of the present application, and the N+1 scanning lines G are numbered G1, G2, ..., G from top to bottom. n , G n+1 , …, G N and G N+1 Similarly, the M data lines D are represented by vertically arranged straight lines in the drawings of the specification of the present application, and the M data lines D are numbered D1, D2, ..., D m ,…,D M The number of the pixel unit P in the drawings of the specification of the present invention corresponds to the number of the scanning line G and the number of the data line D. For example, 1,1 , P 1,2 , P 1,m , P 1,M , P n,1 and P N,1 etc., no more details.

[0035] The nth scanning line G n It is used to output an on signal to the gate of the first thin film transistor T1 on the nth row, so that the M first thin film transistors T1 on the nth row are turned on. The M data lines D are used to output an overcharge voltage to the source of the first thin film transistor T1 on the nth row. The overcharge voltage is input to the M pixel electrodes through the M first thin film transistors T1 on the nth row, so that the M liquid crystal capacitors C1 on the nth row complete the overcharge process. n Stop outputting the start signal, so that the M first thin film transistors T1 in the nth row are turned off, and the n+1th scanning line G n+1 It is used to output a discharge signal to the gates of the M second thin film transistors T2 on the nth row, so that the M second thin film transistors T2 on the nth row are turned on, so that the M pixel electrodes on the nth row discharge to the common electrode to the working voltage through the M second thin film transistors T2 respectively.

[0036] Among them, when n+1≤N, the n+1th scan line G n+1 The discharge signal is output to the gates of the M second thin film transistors T2 in the nth row, and at the same time, the discharge signal is output to the gates of the scan line G in the n+1th row. n+1 The on signal output to the gate of the M first thin film transistors T1 in the n+1th row, that is, the on signal of the scanning line G in the n+1th row n+1 The output discharge signal is the n+1th scan line G n+1 Output start signal, N+1th scan line G N+1For the M pixel units P in the Nth row N,1、…、M The gate of the second thin film transistor T2 outputs a discharge signal.

[0037] Optionally, the overcharge signals output by the M data lines D may be the same or different, and the operating voltages of the NM pixel electrodes may be the same or different, without limitation.

[0038] By setting the number of scan lines G to N+1, the number of data lines D to M, N is a positive integer, M is a positive integer; the number of pixel units P is NM, and the NM pixel units P are arranged in an array, the 1st to Nth scan lines G 1、…、N The gates of the M first thin film transistors T1 are electrically connected to the 2nd to N+1st scanning lines G 2、…、N+1 Each of the M data lines D is electrically connected to the gate electrodes of the M second thin film transistors T2, and each of the M data lines D is electrically connected to the source electrodes of the N first thin film transistors T1; wherein the nth scanning line G n The M data lines D are used to output an on signal to the gate of the first thin film transistor T1 on the nth row, the M data lines D are used to output an overcharge voltage to the source of the first thin film transistor T1 on the nth row, and the n+1th scan line G n+1 It is used to output a discharge signal to the gate of the second thin film transistor T2 on the nth row, where n is a positive integer less than N+1, so that NM pixel electrodes can all be quickly charged, thereby improving the charging speed of the driving circuit 10. At the same time, the driving circuit 10 can use the start-up signal output by the scanning line G to discharge and overcharge the discharge signal pixel electrode, so that the structure of the driving circuit 10 is simple.

[0039] Please refer to Figure 1 The driving circuit 10 also includes a signal driving unit and N+1 gate driving units GOA. The signal driving unit is electrically connected to the same end of the M data lines D. The signal driving unit is used to output an overcharge voltage. The N+1 gate driving units GOA are electrically connected to the same end of the N+1 scan lines G in a one-to-one correspondence. The gate driving unit GOA is used to output a start signal.

[0040] Among them, the N+1 gate drive units GOA are labeled GOA1, GOA2, ..., GOA3 from top to bottom in the drawings of the specification of the present invention. n 、GOA n+1 , …, GOA N 、GOA N+1 .

[0041] Optionally, the N+1 gate drive units GOA may be connected from the first gate drive unit GOA1 to the N+1th gate drive unit GOA N+1 The n+1th gate drive unit GOA outputs the start signal in sequence in the direction of n+1To the M pixel units P in the n+1th row n+1,1、…、M When the on signal is output, the on signal is also input to the M pixel units P in the nth row. n,1、…、M Optionally, both ends of the N+1 scanning lines G are connected to a gate driving unit GOA, and the gate driving units GOA at both ends of each scanning line G simultaneously output a start signal or a discharge signal to the scanning line G to increase the scanning speed of the driving circuit 10.

[0042] Optionally, the overcharge signals output by the signal driving unit to the M data lines D may be the same or different, without limitation.

[0043] By setting the driving circuit 10 to also include a signal driving unit and N+1 gate driving units GOA, the signal driving unit is electrically connected to the same end of the M data lines D, the signal driving unit is used to output an overcharge voltage, the N+1 gate driving units GOA are electrically connected to the same end of the N+1 scan lines G in a one-to-one correspondence, and the gate driving unit GOA is used to output a start signal, so that the NM pixel electrodes can all be quickly charged, thereby improving the charging speed of the driving circuit 10. At the same time, the driving circuit 10 can use the start signal output by the scan line G to discharge the discharge signal pixel electrode, so that the structure of the driving circuit 10 is simple.

[0044] Please refer to Figure 1 , the width-to-length ratio of the second thin film transistor T2 gradually decreases from the direction where the data line D is close to the signal driving unit to the direction where the data line D is far away from the signal driving unit.

[0045] Among them, the aspect ratio refers to the ratio of the width to the length of the transistor channel. The channel width is the lateral dimension of the channel between the source and the drain, and the channel length is the longitudinal dimension of the channel between the source and the drain. The larger the aspect ratio of the thin film transistor, the greater the migration rate of its carriers, that is, the greater the number of carrier migration in the same time, and the more the pixel electrode discharges; the smaller the aspect ratio of the thin film transistor, the smaller the migration rate of its carriers, that is, the smaller the number of carrier migration in the same time, and the less the pixel electrode discharges.

[0046] Since the data line D has resistance, the overcharge voltage output by the signal driving unit gradually decreases from the source end of the data line D to the end of the data line D. Therefore, from the direction where the data line D is close to the signal driving unit to the direction where the data line D is far away from the signal driving unit, the width-to-length ratio of the second thin film transistor T2 gradually decreases, that is, the discharge amount of the pixel electrode gradually decreases, so that the pixel electrodes in each row can reach the working voltage.

[0047] Optionally, when the same end of N+1 scan lines G is respectively connected to a gate driving unit GOA, due to the presence of resistance in the scan line G, the turn-on voltage output by the gate driving unit GOA gradually decreases from the source end of the scan line G to the end of the scan line G, and there is a risk that the turn-on signal cannot fully turn on the first thin film transistor T1 located at the end of the scan line G away from the gate driving unit GOA, resulting in an overcharge voltage on the pixel electrode located at the end of the scan line G away from the gate driving unit GOA being lower than the overcharge voltage on the pixel electrode located at the end of the scan line G close to the gate driving unit GOA. Therefore, from the direction where the scan line G is close to the gate driving unit GOA to the direction where the scan line G is away from the gate driving unit GOA, the width-to-length ratio of the second thin film transistor T2 gradually decreases, that is, the discharge amount of the pixel electrode gradually decreases, so that the pixel electrodes in each row can reach the operating voltage.

[0048] Optionally, when both ends of the N+1 scan lines G are connected to a gate drive unit GOA, the voltage drop caused by the resistance of the scan line G on the turn-on signal is small, and the width-to-length ratio of the second thin film transistor T2 connected to each scan line G may be the same. Optionally, due to factors such as the size, refresh rate, and resolution of the display screen, even if both ends of the scan line G are electrically connected to the gate drive unit GOA, there is a situation where the voltage is insufficient when the turn-on signal is transmitted to the middle position of the extending direction of the scan line G, resulting in the first thin film transistor T1 being unable to be fully turned on, resulting in poor overcharging effect of the pixel electrode. At this time, in the direction from the two ends of the scan line G to the middle of the scan line G, the width-to-length ratio of the second thin film transistor T2 connected to each scan line G may also be different.

[0049] By setting the direction from the data line D close to the signal driving unit to the data line D away from the signal driving unit, the width-to-length ratio of the second thin film transistor T2 gradually decreases, so that the discharge amounts of pixel electrodes in different rows are different, so that pixel electrodes in different rows can all reach the working voltage.

[0050] Please refer to Figure 3The present invention also provides a display panel 100, including a backlight module and a driving circuit 10 in an embodiment of the present invention, wherein the backlight module is arranged on the side of the pixel electrode facing away from the common electrode. Optionally, the display panel 100 is a liquid crystal panel (TFT-LCD panel), and the display panel 100 also includes a first polarizer and a second polarizer, wherein the first polarizer is arranged between the backlight module and the pixel electrode, and the first polarizer is used for filtering the non-polarized light emitted by the backlight module into polarized light with a single vibration direction, so as to filter out light with an unnecessary vibration direction. The second polarizer is arranged on the side of the common electrode facing away from the liquid crystal electrode, and is located between the RGB filter and the common electrode. When the liquid crystal molecules do not change the polarization direction of the light, the light will be completely blocked by the second polarizer and displayed as a dark state. When the liquid crystal molecules change the polarization direction of the light, part of the light can be irradiated onto the RGB filter through the second polarizer and displayed as a bright state.

[0051] The display panel 100 provided by the present invention is provided with a backlight module and a driving circuit 10 in an embodiment of the present invention. The backlight module is provided on the side of the pixel electrode facing away from the common electrode, so that the voltage of the pixel electrode can exceed the working voltage when the start signal ends and reach the working voltage through the discharge process, thereby improving the charging speed of the liquid crystal capacitor C1 and further improving the display effect of the display panel 100.

[0052] Please refer to Figure 3 The present invention also provides a display device 1000, a housing 200 and a display panel 100 in an embodiment of the present invention, wherein the display panel 100 is installed in the housing 200. The display device 1000 may be an electronic reader, an electronic book, a display, a mobile phone, etc., without limitation. The display device 1000 provided by the present invention adopts the housing 200 and the display panel 100 in an embodiment of the present invention, wherein the display panel 100 is installed in the housing 200, so that the voltage of the pixel electrode can exceed the working voltage at the end of the start signal, and reach the working voltage through the discharge process, thereby improving the charging speed of the liquid crystal capacitor C1, and thus improving the display effect of the display device 1000.

[0053] Please refer to Figure 1 , Figure 4 and Figure 5 The present invention further provides a driving method, which is applied to the driving circuit 10 in the embodiment of the present invention, comprising: in a first period, the scanning line G outputs an on signal to the gate of the first thin film transistor T1, and the data line D outputs an overcharge voltage to the source of the first thin film transistor T1, so that the liquid crystal capacitor C1 is charged and the pixel electrode has the overcharge voltage; in a second period, a discharge signal is output to the gate of the second thin film transistor T2, so that the liquid crystal capacitor C1 is discharged and the pixel electrode has a working voltage.

[0054] Optional, please refer to Figure 4and Figure 5 , W1 is the voltage waveform of the pixel electrode in the present invention, W2 is the voltage waveform of the pixel electrode in the comparative example, W3 is the voltage waveform of the pixel electrode when the data line D outputs the overcharge voltage in the present invention but the second thin film transistor T2 is not set, the voltage value of the turn-on signal is V1, the voltage value of the overcharge voltage is V2, the voltage value of the working voltage is V3, and the maximum voltage value of the pixel electrode in the comparative example is V4, wherein V2>V3>V4. Optionally, the voltage value of the discharge signal can be V1, or other voltage values ​​that can turn on the second thin film transistor T2, without limitation.

[0055] Specifically, when the display panel 100 is working and displaying, in the first period, the scan line G outputs a start signal to the gate of the first thin film transistor T1 to turn on the first thin film transistor T1, and the data line D is used to output an overcharge voltage to the source of the first thin film transistor T1. The overcharge voltage is input to the pixel electrode through the first thin film transistor T1, so that the voltage of the pixel electrode reaches the overcharge voltage. At this time, the common voltage of the common electrode is less than the overcharge voltage of the pixel electrode, and the liquid crystal capacitor C1 completes the overcharge process. In the second period, the scan line G stops inputting a start signal to the gate of the first thin film transistor T1, so that the first thin film transistor T1 is turned off, and the gate of the second thin film transistor T2 inputs a discharge signal, so that the second thin film transistor T2 is turned on, and the pixel electrode discharges to the common electrode through the second thin film transistor T2 to the working voltage. Optionally, the discharge signal can be output by other scan lines G, or by the control chip in the display panel 100, without limitation.

[0056] Before the end of the first period, the data line D outputs the working voltage to the pixel electrode through the first thin film transistor T1 so that the voltage of the pixel electrode rises from 0V (volts) to the working voltage. After the pixel electrode rises to the working voltage, it continues to charge until the overcharge voltage is reached at the end of the first period. In the second period, the gate of the second thin film transistor T2 is opened, and the pixel electrode discharges to the common electrode through the second thin film transistor T2 until the end of the second period, at which time the pixel electrode reaches the working voltage, and the pixel electrode maintains the working voltage until the display of the picture of the frame ends.

[0057] Please refer to Figure 5 , the maximum voltage value of the pixel electrode in the comparative example is V4, and V4 is less than the voltage value V3 of the working voltage, that is, when the turn-on signal of the driving circuit 10 of the comparative example ends, the voltage of the pixel electrode is less than the working voltage. However, through the driving method provided by the present invention, the voltage of the pixel electrode can exceed the working voltage when the turn-on signal ends, and reach the working voltage through the discharge process, thereby improving the charging speed of the liquid crystal capacitor C1.

[0058] Please refer to Figure 1 , Figure 4 and Figure 5 , there are N+1 scanning lines G, there are M data lines D, N is a positive integer, M is a positive integer; there are NM pixel units P, the NM pixel units P are arranged in an array, the 1st to Nth scanning lines G 1、…、N The gates of the M first thin film transistors T1 are electrically connected to the 2nd to N+1st scanning lines G 2、…、N+1 The M data lines D are electrically connected to the gates of the M second thin film transistors T2, and the M data lines D are electrically connected to the sources of the N first thin film transistors T1; a driving cycle of the driving circuit 10 sequentially passes through the first time period t1, ..., the nth time period t n , the n+1th period t n+1 , ..., N+1th period t N+1 , where n is a positive integer less than or equal to N; in the nth time period t n , the nth scan line G n An on signal is output to the gate of the first thin film transistor T1 on the nth row, and the M data lines D output an overcharge voltage to the source of the first thin film transistor T1 on the nth row, so that the liquid crystal capacitor C1 on the nth row is charged and the pixel electrode on the nth row has an overcharge voltage; in the n+1th period t n+1 , the n+1th scanning line G n+1 A discharge signal is output to the gate of the second thin film transistor T2 on the nth row, so that the liquid crystal capacitor C1 on the nth row is discharged and the pixel electrode on the nth row has an operating voltage.

[0059] Optionally, the voltage value of the start signal and the voltage value of the discharge signal are both V1, the voltage value of the overcharge voltage is V2, the voltage value of the working voltage is V3, and the maximum voltage value of the pixel electrode in the comparative example is V4, wherein V2>V3>V4.

[0060] Specifically, in the nth period t n , the nth scan line G n An on signal is output to the gate of the first thin film transistor T1 on the nth row, so that the M first thin film transistors T1 on the nth row are turned on, and the M data lines D output an overcharge voltage to the source of the first thin film transistor T1 on the nth row. The overcharge voltage is respectively input to the M pixel electrodes through the M first thin film transistors T1 on the nth row, so that the M liquid crystal capacitors C1 on the nth row complete the overcharge process. In the n+1th period t n+1 , the nth scan line G n Stop outputting the start signal, so that the M first thin film transistors T1 in the nth row are turned off, and the n+1th scanning line G n+1A discharge signal is output to the gates of the M second thin film transistors T2 on the nth row, so that the M second thin film transistors T2 on the nth row are turned on, so that the M pixel electrodes on the nth row are discharged to the common electrode to the operating voltage through the M second thin film transistors T2 respectively, and the pixel electrodes maintain the operating voltage until the end of the driving cycle T.

[0061] Among them, when n+1≤N, the n+1th scan line G n+1 At the n+1th time period t n+1 The discharge signal is output to the gates of the M second thin film transistors T2 in the nth row, and at the same time, the discharge signal is output to the gates of the scan line G in the n+1th row. n+1 The on signal output to the gate of the M first thin film transistors T1 in the n+1th row, that is, the on signal of the scanning line G in the n+1th row n+1 The output discharge signal is the n+1th row scanning line G n+1 Output start signal, N+1th scan line G N+1 For the M pixel units P in the Nth row N,1 、…、M The gate of the second thin film transistor T2 outputs a discharge signal.

[0062] Among them, in the Nth period t N , the Nth scan line G N An on signal is output to the gate of the first thin film transistor T1 on the Nth row, so that the M first thin film transistors T1 on the Nth row are turned on, and the M data lines D output an overcharge voltage to the source of the first thin film transistor T1 on the Nth row. The overcharge voltage is respectively input to the M pixel electrodes through the M first thin film transistors T1 on the Nth row, so that the M liquid crystal capacitors C1 on the Nth row complete the overcharge process. In the N+1th period t N+1 , the Nth scan line G N Stop outputting the start signal, so that the M first thin film transistors T1 in the Nth row are turned off, and the N+1th scanning line G N+1 A discharge signal is output to the gates of the M second thin film transistors T2 on the Nth row, so that the M second thin film transistors T2 on the Nth row are turned on, so that the M pixel electrodes on the Nth row are discharged to the common electrode to the working voltage through the M second thin film transistors T2 respectively. At this time, the display panel 100 completes the picture display of one frame time.

[0063] Optionally, from the N+1th scan line G N+1 Towards the direction of the first scanning line G1, the width-to-length ratio of the second thin film transistor T2 gradually decreases, that is, from the N+1th scanning line G N+1 Towards the direction of the first scanning line G1, the discharge amount of the pixel electrode gradually decreases.

[0064] Through the driving method provided by the present invention, the voltage of each pixel electrode can exceed the working voltage when the start signal ends, and the start signal output by the scanning line G in the next row is used as a discharge signal to discharge the pixel electrode to the working voltage. There is no need to set up an additional driving structure to output the discharge signal, which simplifies the structure and driving process of the driving circuit 10 and improves the charging speed of the liquid crystal capacitor C1.

[0065] Please refer to Figure 1 , Figure 4 and Figure 5 The driving circuit 10 further includes N+1 gate driving units GOA, and the N+1 gate driving units GOA are electrically connected to the same end of the N+1 scanning lines G in a one-to-one correspondence; in the nth time period t n , the nth gate drive unit GOA n Towards the nth scan line G n Output start signal; in the n+1th period t n+1 , the n+1th gate drive unit GOA n+1 Towards the n+1th scanning line G n+1 Output discharge signal.

[0066] Specifically, in the nth period t n , the nth gate drive unit GOA n Towards the nth scan line G n Output the start signal to turn on the M first thin film transistors T1 in the nth row, and the signal driving unit outputs the overcharge voltage to the source of the first thin film transistors T1 in the nth row through the M data lines D. The overcharge voltage is respectively input to the M pixel electrodes through the M first thin film transistors T1 in the nth row, so that the M liquid crystal capacitors C1 in the nth row complete the overcharge process. n+1 , the nth gate drive unit GOA n Stop scanning the nth scan line G n Output the start signal to turn off the M first thin film transistors T1 in the nth row, and the n+1th gate drive unit GOA n+1 Towards the n+1th scanning line G n+1 The discharge signal is outputted to turn on the M second thin film transistors T2 on the nth row, so that the M pixel electrodes on the nth row are discharged to the common electrode to the working voltage through the M second thin film transistors T2 respectively.

[0067] Among them, when n+1≤N, the n+1th gate drive unit GOA n+1 Towards the n+1th scanning line G n+1 Output discharge signal, at the same time, the n+1th gate drive unit GOA n+1 Towards the n+1th scanning line G n+1Output start signal, that is, the n+1th gate drive unit GOA n+1 Towards the nth scan line G n The output discharge signal is also used as the n+1th scanning line G n+1 Output start signal.

[0068] At the Nth time period t N , the Nth gate drive unit GOA N Towards the Nth scan line G N Output the start signal to turn on the M first thin film transistors T1 in the Nth row, and the signal driving unit outputs the overcharge voltage to the source of the first thin film transistors T1 in the Nth row through the M data lines D. The overcharge voltage is respectively input to the M pixel electrodes through the M first thin film transistors T1 in the Nth row, so that the M liquid crystal capacitors C1 in the Nth row complete the overcharge process. N+1 , the Nth gate drive unit GOA N Stop outputting the start signal, so that the M first thin film transistors T1 in the Nth row are turned off, and the N+1th gate driving unit GOA N+1 Towards the Nth scan line G N The discharge signal is outputted to turn on the M second thin film transistors T2 on the Nth row, so that the M pixel electrodes on the Nth row are discharged to the common electrode to the working voltage through the M second thin film transistors T2 , and the display panel 100 completes the picture display of one frame.

[0069] Through the driving method provided by the present invention, the voltage of each pixel electrode can exceed the working voltage when the start signal output by the gate driving unit GOA of the row ends, and the start signal output by the next gate driving unit GOA is used as a discharge signal to discharge the pixel electrode to the working voltage. There is no need to set up an additional driving structure to output the discharge signal, which simplifies the structure and driving process of the driving circuit 10 and improves the charging speed of the liquid crystal capacitor C1.

[0070] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0071] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A pixel unit, characterized in that: include: a first thin film transistor; a pixel electrode electrically connected to the drain electrode of the first thin film transistor; A common electrode, forming a liquid crystal capacitor with the pixel electrode; a second thin film transistor, wherein a source electrode of the second thin film transistor is electrically connected to the pixel electrode, and a drain electrode of the second thin film transistor is electrically connected to the common electrode; Among them, the gate of the first thin film transistor is used to input an on signal, and the source of the first thin film transistor is used to input an overcharge voltage to charge the liquid crystal capacitor and make the pixel electrode have an overcharge voltage; the gate of the second thin film transistor is used to input a discharge signal to discharge the liquid crystal capacitor and make the pixel electrode have an operating voltage, and the overcharge voltage is greater than the operating voltage.

2. A driving circuit, characterized in that: The invention comprises a scan line, a data line and the pixel unit as claimed in claim 1, wherein the gate electrode of the first thin film transistor is electrically connected to the scan line, and the source electrode of the first thin film transistor is electrically connected to the data line.

3. The driving circuit according to claim 2, characterized in that: The number of the scan lines is N+1, the number of the data lines is M, N is a positive integer, and M is a positive integer; The number of the pixel units is NM, and the NM pixel units are arranged in an array, the first to N scanning lines are electrically connected to the gates of the M first thin film transistors, the second to N+1 scanning lines are electrically connected to the gates of the M second thin film transistors, and the M data lines are electrically connected to the sources of the N first thin film transistors; Among them, the nth scan line is used to output the turn-on signal to the gate of the first thin film transistor on the nth row, the M data lines are used to output the overcharge voltage to the source of the first thin film transistor on the nth row, and the n+1th scan line is used to output the discharge signal to the gate of the second thin film transistor on the nth row, and n is a positive integer less than N+1.

4. The driving circuit according to claim 3, characterized in that: The driving circuit also includes a signal driving unit and N+1 gate driving units, the signal driving unit is electrically connected to the same end of the M data lines, the signal driving unit is used to output the overcharge voltage, the N+1 gate driving units are electrically connected to the same end of the N+1 scan lines in a one-to-one correspondence, and the gate driving unit is used to output the start signal.

5. The driving circuit according to claim 4, characterized in that: The width-to-length ratio of the second thin film transistor gradually decreases from a direction in which the data line approaches the signal driving unit to a direction in which the data line moves away from the signal driving unit.

6. A display panel, characterized in that: It comprises a backlight module and a driving circuit as claimed in any one of claims 2 to 5, wherein the backlight module is arranged on a side of the pixel electrode facing away from the common electrode.

7. A display device, characterized in that: A housing and a display panel as claimed in claim 6, wherein the display panel is installed in the housing.

8. A driving method, characterized in that: A driving circuit as claimed in any one of claims 2 to 5, comprising: In the first period, the scan line outputs an on signal to the gate of the first thin film transistor, and the data line outputs an overcharge voltage to the source of the first thin film transistor, so as to charge the liquid crystal capacitor and make the pixel electrode have the overcharge voltage; In the second period, a discharge signal is output to the gate of the second thin film transistor to discharge the liquid crystal capacitor and enable the pixel electrode to have an operating voltage.

9. The driving method according to claim 8, characterized in that: The number of the scan lines is N+1, the number of the data lines is M, N is a positive integer, and M is a positive integer; the number of the pixel units is NM, the NM pixel units are arranged in an array, the first to N scan lines are electrically connected to the gates of the M first thin film transistors, the second to N+1 scan lines are electrically connected to the gates of the M second thin film transistors, and the M data lines are electrically connected to the sources of the N first thin film transistors; A driving cycle of the driving circuit sequentially passes through the 1st time period, ..., the nth time period, the n+1th time period, ..., the N+1th time period, wherein n is a positive integer less than or equal to N; In the nth period, the nth scan line outputs the on signal to the gate of the first thin film transistor on the nth row, and the M data lines output the overcharge voltage to the source of the first thin film transistor on the nth row, so that the liquid crystal capacitor on the nth row is charged and the pixel electrode on the nth row has the overcharge voltage; In the n+1th time period, the n+1th scan line outputs the discharge signal to the gate of the second thin film transistor on the nth row, so that the liquid crystal capacitor on the nth row is discharged and the pixel electrode on the nth row has an operating voltage.

10. The driving method according to claim 8, characterized in that: The driving circuit further includes N+1 gate driving units, and the N+1 gate driving units are electrically connected to the same end of the N+1 scanning lines in a one-to-one correspondence; In the nth time period, the nth gate driving unit outputs the start signal to the nth scan line; In the n+1th time period, the n+1th gate driving unit outputs the discharge signal to the n+1th scanning line.

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