Scanning driving circuit and display panel

Abstract

The invention provides a scanning driving circuit and a display panel. The scanning driving circuit comprises m stages of cascaded scanning driving units, and each stage of scanning driving unit comprises a clock signal input end, a scanning signal output end, a pull-up control node, a pull-down control node, a pull-up module, a first pre-pull-down module, a pull-down maintaining module and an output module. And the first pre-pull-down module responds to a pre-pull-down signal corresponding to the scanning driving unit at the level, and pulls down the pull-down control node to a low level, so that the pull-down maintaining module does not work. A starting signal corresponding to the ith-level scanning driving unit is a scanning signal output by the (i-n) th-level scanning driving unit, and a pre-pull-down signal corresponding to the ith-level scanning driving unit is a level signal output by a pull-up control node in the (i-n-1) th-level scanning driving unit. According to the scanning driving circuit, the size of a lower tube in an inverter circuit does not need to be set to be very large, even the lower tube can be omitted, and the area of the scanning driving circuit can be reduced.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a scan drive circuit and a display panel. Background Art

[0002] As liquid crystal display technology continues to mature, liquid crystal displays (LCD) have been widely used in various fields. At present, LCDs generally use gate driver less (GDL) technology, and the LCD gate scan drive circuit (i.e., GDL circuit) is made on the array substrate. Since the GDL circuit is based on the external circuit providing only a few control signals, the line scan drive circuit is made using the same process as the thin film transistor to achieve the line-by-line scan drive function, thus saving integrated circuits related to the scan drive and reducing the production cost of the liquid crystal display.

[0003] In the GDL circuit, during the time period when the pull-up control node Q is at a high potential, the inverter circuit is controlled by the high potential of the pull-up control node Q to achieve pull-down maintenance of the pull-down control node Qb level. However, during the charging process of the pull-up control node Q, since the upper tube and the lower tube in the inverter circuit are turned on at the same time, in order to allow the inverter to pull down the pull-down control node Qb to a low potential as quickly as possible, the size of the lower tube needs to be set to be particularly large. Usually, the size of the lower tube is more than ten times the size of the upper tube. This will increase the area of ​​the GDL circuit, which is not conducive to the narrow frame design of the display. Summary of the invention

[0004] In view of this, the main purpose of the present application is to propose a scan drive circuit and a display panel, aiming to solve the problem of a large GDL circuit area in existing LCDs.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a scan driving circuit, which is applied to a display panel, and the display panel includes m rows of pixel units arranged in sequence; the scan driving circuit includes m-level cascaded scan driving units, and the m-level scan driving units correspond one-to-one to the m rows of pixel units, and each level of the scan driving unit includes a clock signal input terminal, a scan signal output terminal, a pull-up control node, a pull-down control node, a pull-up module, a first pre-pull-down module, a pull-down maintenance module and an output module. The clock signal input terminal is used to receive the clock signal corresponding to the scan driving unit of this level; the pull-up module is electrically connected to the pull-up control node, and the pull-up module pulls up the pull-up control node to a high level in response to the start signal corresponding to the scan driving unit of this level; the first pre-pull-down module is electrically connected to the pull-down control node, and the first pre-pull-down module pulls down the pull-down control node to a low level in response to the pre-pull-down signal corresponding to the scan driving unit of this level; the pull-down maintaining module is electrically connected to the pull-down control node and the pull-up control node, and the pull-down maintaining module is used to work when the pull-down control node is at a high level and pull down the pull-up control node to a low level, and It does not work when the pull-down control node is at a low level; the output module is electrically connected to the clock signal input terminal, the pull-up control node and the scan signal output terminal, and the output module is used to output a scan signal through the scan signal output terminal based on the clock signal received at the clock signal input terminal when the pull-up control node is at a high level; wherein the start signal corresponding to the i-th level scan driving unit is the scan signal output by the in-th level scan driving unit, and the pre-pull-down signal corresponding to the i-th level scan driving unit is the level signal output by the pull-up control node in the in-1-th level scan driving unit; i, m and n are all positive integers, i≤m, 1≤in-1.

[0006] The scanning driving circuit provided by the present application sets a first pre-pull-down module in each level of scanning driving unit, and allows the first pre-pull-down module to receive a corresponding pre-pull-down signal to pull down the pull-down control node to a low level before the pull-up module in the scanning driving unit of the same level pulls up the pull-up control node to a high level. Compared with the method in the prior art in which the pull-down control node is pulled down to a low level by using the high level of the pull-up control node after the pull-up control node is charged to a high level by an inverter circuit, since the first pre-pull-down module pulls down the pull-down control node to a low level in advance before the pull-up module charges the pull-up control node, the pull-down time is advanced. Therefore, it is not necessary to set the size of the lower tube in the inverter circuit to be particularly large or even to cancel the lower tube. In this way, the area of ​​the scanning driving circuit can be reduced, which is beneficial to the narrow frame design of the display panel.

[0007] In some embodiments, each level of the scan driving unit also includes an inverter circuit, which is electrically connected to the pull-up control node and the pull-down control node. The inverter circuit is used to control the pull-down maintaining module to pull down and maintain the scan signal output end and the pull-up control node at a low level after the pull-up control node is pulled down to a low level.

[0008] In some embodiments, the inverter circuit includes a low-frequency signal input terminal, a first switch tube, a second switch tube, a third switch tube and a fourth switch tube. The low-frequency signal input terminal is used to receive a low-frequency signal; the first switch tube includes a first connection terminal, a second connection terminal and a control terminal, and the first connection terminal and the control terminal of the first switch tube are both electrically connected to the low-frequency signal input terminal; the second switch tube includes a first connection terminal, a second connection terminal and a control terminal, and the first connection terminal of the second switch tube is electrically connected to the low-frequency signal input terminal, and the control terminal of the second switch tube is electrically connected to the second connection terminal of the first switch tube; the third switch tube includes a first connection terminal, a second connection terminal and a control terminal, and the first connection terminal of the third switch tube is electrically connected to the second connection terminal of the first switch tube, and the second connection terminal of the third switch tube is used to receive a low-level voltage, and the control terminal of the third switch tube is electrically connected to the pull-up control node; the fourth switch tube includes a first connection terminal, a second connection terminal and a control terminal, and the first connection terminal of the fourth switch tube is electrically connected to the second connection terminal of the second switch tube, and the second connection terminal of the fourth switch tube is used to receive the low-level voltage, and the control terminal of the fourth switch tube is electrically connected to the pull-up control node.

[0009] In some embodiments, each level of the scan driving unit also includes a second pre-pull-down module, which is electrically connected to the control end of the second switch tube. The second pre-pull-down module is used to respond to the pre-pull-down signal corresponding to the scan driving unit at this level, and pull the control end of the second switch tube to a low level, thereby turning off the second switch tube.

[0010] In some embodiments, the first pre-pull-down module includes a fifth switch tube, the fifth switch tube includes a first connection end, a second connection end and a control end, the first connection end of the fifth switch tube is electrically connected to the pull-up control node, the second connection end of the fifth switch tube is used to receive a low-level voltage, and the control end of the fifth switch tube is used to receive a pre-pull-down signal corresponding to the scan driving unit at this level.

[0011] In some embodiments, the second pre-pull-down module includes a sixth switch tube, the sixth switch tube includes a first connection end, a second connection end and a control end, the first connection end of the sixth switch tube is electrically connected to the control end of the second switch tube, the second connection end of the sixth switch tube is used to receive the low-level voltage, and the control end of the sixth switch tube is used to receive the pre-pull-down signal corresponding to the scan driving unit at this level.

[0012] In some embodiments, a ratio of a channel width-to-length ratio of the fourth switch transistor to a channel width-to-length ratio of the second switch transistor is less than 2.

[0013] In some embodiments, a ratio of a channel width-to-length ratio of the third switch transistor to a channel width-to-length ratio of the first switch transistor is less than 2.

[0014] In some embodiments, the pull-down maintaining module includes a seventh switch tube and an eighth switch tube, the seventh switch tube includes a first connection end, a second connection end and a control end, the first connection end of the seventh switch tube is electrically connected to the pull-up control node, the second connection end of the seventh switch tube is used to receive a low-level voltage, and the control end of the seventh switch tube is electrically connected to the pull-down control node; the eighth switch tube includes a first connection end, a second connection end and a control end, the first connection end of the eighth switch tube is electrically connected to the scan signal output end, the second connection end of the eighth switch tube is used to receive a low-level voltage, and the control end of the eighth switch tube is electrically connected to the pull-down control node.

[0015] A second aspect of the present application further provides a display panel, which includes m rows of pixel units and the scan drive circuit described in the first aspect.

[0016] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a display panel provided in an embodiment of the present application; Figure 2 A topological diagram of a scan drive unit provided in an embodiment of the present application; Figure 3 A circuit diagram of a scan driving unit provided in an embodiment of the present application.

[0018] The following are the descriptions of the reference numerals: 100-display panel; 1-scanning driving circuit; 102-display area; 101-non-display area; 1022-data line; 1021-scanning line; P-pixel unit; GDL(i)-scanning driving unit; GDL(1)-scanning driving unit; GDL(2)-scanning driving unit; GDL(m)-scanning driving unit; Clk-clock signal input terminal; G(i)-scanning signal output terminal; Q(i)-pull-up control node; Qb(i)-pull-down control node; Qb(i)'-pull-down control node; 10-pull-up module; 30-pull-down maintaining module; 30'-pull-down maintaining module; 40-first pre-pull-down module; 40'-first pre-pull-down module; 20-output module; 50-inverter circuit; 50'-inverter circuit; VDDO-first low-frequency signal input terminal; V DDN-second low-frequency signal input terminal; T1-first switch tube; T1'-first switch tube; T2-second switch tube; T2'-second switch tube; T3-third switch tube; T3'-third switch tube; T4-fourth switch tube; T4'-fourth switch tube; 60-second pre-pull-down module; 60'-second pre-pull-down module; T5-fifth switch tube; T5'-fifth switch tube; T6-sixth switch tube; T6'-sixth switch tube; T7-seventh switch tube; T7'-seventh switch tube; T8-eighth switch tube; T8'-eighth switch tube; T9-ninth switch tube; T10-tenth switch tube; C-capacitor; T11-eleventh switch tube; T12-twelfth switch tube; T13-thirteenth switch tube; VGH-high level voltage; VGL-low level voltage; RST-reset signal.

[0019] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] In addition, the term "first", "second" etc. in the specification of the present application is used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable in appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, method, system, product or equipment comprising a series of steps or modules need not be limited to those steps or modules clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products or equipment.

[0022] It should be noted that, in the absence of conflict, the features in the embodiments of the present application may be combined with each other.

[0023] Please also read Figure 1~Figure 2 , Figure 1 A schematic diagram of a display panel provided in an embodiment of the present application; Figure 2 A topological diagram of a scan drive unit provided in an embodiment of the present application. The present application provides a scan drive circuit 1, the scan drive circuit 1 is applied to a display panel 100, the display panel 100 includes m scan lines 1021 and j data lines 1022, the m scan lines 1021 and the j data lines 1022 are cross-arranged to define a plurality of sub-pixel areas, each sub-pixel area is provided with a pixel unit P, and a plurality of the pixel units P are arranged in m rows and j columns. Wherein, m is an integer greater than 1. When driving the display panel for display, a scan signal can be written to each of the scan lines 1021 row by row according to the picture to be displayed, and a data voltage signal can be written to each of the data lines 1022 at the same time, so that the pixel units P in the display panel 100 are lit row by row.

[0024] The scanning driving circuit 1 includes m-level scanning driving units connected in cascade, and the m-level scanning driving units correspond to m rows of pixel units P one by one. The m-level scanning driving units are used to output scanning signals in sequence to scan the m rows of pixel units P row by row. Figure 1 As shown, the first-level scanning driving unit is marked as GDL(1), and its scanning signal output terminal is G(1); the second-level scanning driving unit is marked as GDL(2), and its scanning signal output terminal is G(2)... The m-th level scanning driving unit is marked as GDL(m), and its scanning signal output terminal is G(m).

[0025] In the embodiment of the present application, the circuit structures of the scan driving units at each level are the same. The circuit structure and working principle of the scan driving unit are described in detail below by taking the i-th level scan driving unit GDL(i) as an example, where i is a positive integer, i≤m.

[0026] like Figure 2 As shown, the i-th level scan driving unit GDL(i) includes a clock signal input terminal Clk, a scan signal output terminal G(i), a pull-up control node Q(i), a pull-down control node Qb(i), a pull-up module 10, a pull-down maintaining module 30, a first pre-pull-down module 40 and an output module 20. The scan signal output by the scan signal output terminal G(i) of the i-th level scan driving unit GDL(i) is also marked as G(i).

[0027] The clock signal input terminal Clk is used to receive a clock signal corresponding to the scan driving unit at this stage.

[0028] The pull-up module 10 is electrically connected to the pull-up control node Q(i). The pull-up module 10 pulls up the pull-up control node Q(i) to a high level in response to a start signal corresponding to the scan driving unit at this level.

[0029] The pull-down maintaining module 30 is electrically connected to the pull-down control node Qb(i) and the pull-up control node Q(i). The pull-down maintaining module 30 is used to work when the pull-down control node Qb(i) is at a high level and pull the pull-up control node Q(i) down to a low level, and not work when the pull-down control node Qb(i) is at a low level.

[0030] The first pre-pull-down module 40 is electrically connected to the pull-down control node Qb(i). The first pre-pull-down module 40 responds to the pre-pull-down signal corresponding to the scan driving unit at this level to pull down the pull-down control node Qb(i) to a low level, so that the pull-down maintaining module 30 does not work.

[0031] The output module 20 is electrically connected to the clock signal input terminal Clk, the pull-up control node Q(i) and the scan signal output terminal G(i). The output module 20 is used to output a scan signal through the scan signal output terminal G(i) based on the clock signal received by the clock signal input terminal Clk when the pull-up control node Q(i) is at a high level.

[0032] The start signal corresponding to the i-th level scanning driving unit GDL(i) is the scanning signal G(in) output by the in-th level scanning driving unit GDL(in), and the pre-pull-down signal corresponding to the i-th level scanning driving unit GDL(i) is the level signal output by the pull-up control node Q(in-1) in the in-1-th level scanning driving unit GDL(in-1). n is a positive integer, 1≤in-1.

[0033] The scan driving circuit 1 provided by the present application is provided with a first pre-pull-down module in each level of the scan driving unit, and the first pre-pull-down module receives a corresponding pre-pull-down signal to pull down the pull-down control node to a low level before the pull-up module in the scan driving unit of the same level pulls up the pull-up control node to a high level. Compared with the method in the prior art in which the pull-down control node is pulled down to a low level by using the high level of the pull-up control node after the pull-up control node is charged to a high level by an inverter circuit, the first pre-pull-down module pulls down the pull-down control node to a low level in advance before the pull-up module charges the pull-up control node, and the pull-down time is advanced. Therefore, it is not necessary to set the size of the lower tube in the inverter circuit to be particularly large, or even to cancel the lower tube. In this way, the area of ​​the scan driving circuit 1 can be reduced, which is beneficial to the narrow frame design of the display panel 100.

[0034] Exemplarily, n=4, m=1080, at this time, for each level of scanning driving unit GDL(i) in the 6th to 1080th levels, the start signal corresponding to the scanning driving unit of this level is the scanning signal G(i-4) output by the previous 4th level scanning driving unit GDL(i-4), and the pre-pull-down signal corresponding to the scanning driving unit of this level is the level signal output by the pull-up control node Q(i-5) in the previous 5th level scanning driving unit GDL(i-5). In other embodiments, n and m can also be other values, which are not limited here.

[0035] In some embodiments, for each scan driving unit in the 1st to nth stages in the scan driving circuit 1, the start signal and the pre-pull-down signal corresponding to the scan driving unit at this stage can be a frame start signal STV corresponding to each frame of display image.

[0036] In some embodiments, the i-th level scan driving unit GDL(i) also includes an inverter circuit 50, which is electrically connected to the pull-up control node Q(i) and the pull-down control node Qb(i). The inverter circuit 50 is used to control the pull-down maintaining module 30 to pull down and maintain the scan signal output terminal G(i) and the pull-up control node Q(i) at a low level after the pull-up control node Q(i) is pulled down to a low level.

[0037] Among them, the level signal output by the pull-up control node Q(i) can be regarded as the input signal of the inverter circuit 50, and the level signal output by the pull-down control node Qb(i) can be regarded as the output signal of the inverter circuit 50. The pull-up control node Q(i) is used to invert the level of the pull-up control node Q(i) and then output it to the pull-down control node Qb(i). That is to say, when the pull-up control node Q(i) is at a high level, the pull-down control node Qb(i) is at a low level; when the pull-up control node Q(i) is at a low level, the pull-down control node Qb(i) is at a high level.

[0038] It should be noted that in the embodiment of the present application, the specific circuit structure of the pull-up module 10, the pull-down maintaining module 30, the first pre-pull-down module 40, the output module 20, the inverter circuit 50 and the second pre-pull-down module 60 described below is not limited, as long as the corresponding functions can be achieved.

[0039] In addition, the embodiment of the present application does not limit the number of the pull-down maintaining module, the first pre-pull-down module, the inverter circuit, the second pre-pull-down module, and the pull-down control node. For example, in one embodiment, each level of the scan driving unit may include a pull-down maintaining module 30, a first pre-pull-down module 40, an inverter circuit 50, and a second pre-pull-down module 60. In another embodiment, Figure 3 As shown, each level of the scan driving unit may also include two pull-down maintaining modules (i.e., pull-down maintaining module 30, pull-down maintaining module 30'), two first pre-pull-down modules (i.e., first pre-pull-down module 40, first pre-pull-down module 40'), two inverter circuits (i.e., inverter circuit 50, inverter circuit 50'), two pull-down control nodes (i.e., pull-down control node Qb(i), pull-down control node Qb(i)') and two second pre-pull-down modules (i.e., second pre-pull-down module 60, second pre-pull-down module 60'). In this case, the pull-down control node Qb(i), the pull-down maintaining module 30, the first pre-pull-down module Block 40, the inverter circuit 50, and the second pre-pull-down module 60 together constitute a first group of control subunits, and the pull-down control node Qb(i)', the pull-down maintaining module 30', the first pre-pull-down module 40', the inverter circuit 50', and the second pre-pull-down module 60' together constitute a second group of control subunits. The first group of control subunits and the second group of control subunits can work alternately, for example, the first group of control subunits works in odd frames, and the second group of control subunits works in even frames. In this way, the working time of each group of control subunits can be shortened, the stability of the circuit can be improved, and the service life of the circuit can be extended.

[0040] Combine the following Figure 3, the circuit structure of the i-th level scanning driving unit GDL(i) is introduced in detail. Among them, the circuit structure of the first group of control subunits and the second group of control subunits are the same, and the first group of control subunits is taken as an example for introduction.

[0041] In some embodiments, the inverter circuit 50 includes a low-frequency signal input terminal, a first switch tube T1, a second switch tube T2, a third switch tube T3, and a fourth switch tube T4.

[0042] Among them, the low-frequency signal input terminal is used to receive a low-frequency signal. It should be noted that the low-frequency signal input terminal in the first group of control subunits is marked as the first low-frequency signal input terminal VDDO, and the low-frequency signal input terminal in the second group of control subunits is marked as the second low-frequency signal input terminal VDDN. The low-frequency signals received by these two low-frequency signal input terminals are inverted signals, that is, when the first low-frequency signal input terminal VDDO is at a high level, the second low-frequency signal input terminal VDDN is at a low level; when the first low-frequency signal input terminal VDDO is at a low level, the second low-frequency signal input terminal VDDN is at a high level. Exemplarily, the first low-frequency signal input terminal VDDO is at a high level in odd frames and at a low level in even frames; the second low-frequency signal input terminal VDDN is at a low level in odd frames and at a high level in even frames.

[0043] The first switch tube T1 includes a first connection end, a second connection end and a control end. The first connection end and the control end of the first switch tube T1 are both electrically connected to the low-frequency signal input end.

[0044] The second switch tube T2, i.e., the upper tube of the inverter circuit 50, includes a first connection end, a second connection end, and a control end. The first connection end of the second switch tube T2 is electrically connected to the low-frequency signal input end, and the control end of the second switch tube T2 is electrically connected to the second connection end of the first switch tube T1.

[0045] The third switch tube T3 includes a first connection end, a second connection end and a control end. The first connection end of the third switch tube T3 is electrically connected to the second connection end of the first switch tube T1. The second connection end of the third switch tube T3 is used to receive the low-level voltage VGL. The control end of the third switch tube T3 is electrically connected to the pull-up control node Q(i).

[0046] The fourth switch tube T4, i.e., the lower tube of the inverter circuit 50, includes a first connection end, a second connection end, and a control end. The first connection end of the fourth switch tube T4 is electrically connected to the second connection end of the second switch tube T2. The second connection end of the fourth switch tube T4 is used to receive the low-level voltage VGL. The control end of the fourth switch tube T4 is electrically connected to the pull-up control node Q(i).

[0047] When the first group of control subunits is working, VDDO is at a high level. When the start signal and the pre-pull-down signal corresponding to the i-th level scan driving unit GDL(i) have not arrived, that is, the pull-up control node Q(in-1) of the in-1-th level scan driving unit GDL(in-1) is also at a low level, and the scan signal output by the in-th level scan driving unit GDL(in) is at a low level, the pull-up control node Q(i) is at a low level, so that the control end of the third switch tube T3 and the control end of the fourth switch tube T4 are both at a low level, so that the third switch tube T3 and the fourth switch tube T4 are both turned off. At this time, the first switch tube T1 is turned on and the control end of the second switch tube T2 is pulled up to a high level, so that the second switch tube T2 is turned on and the pull-down control node Qb(i) is pulled up to a high level. In this way, the pull-down maintaining module 30 works when the pull-down control node Qb(i) is at a high level and maintains the pull-up control node Q(i) at a low level. When the pre-pull-down signal arrives and the start signal does not arrive, that is, the pull-up control node Q(in-1) of the in-1th level scan driving unit GDL(in-1) is at a high level, and the scan signal output by the in-th level scan driving unit GDL(in) is at a low level, the first pre-pull-down module 40 pulls the pull-down control node Qb(i) down to a low level in response to the pre-pull-down signal, thereby stopping the pull-down maintaining module 30. Since the pull-down control node Qb(i) has been pulled down to a low level before the start signal arrives, in some embodiments, the fourth switch tube T4 may also be cancelled.

[0048] In some embodiments, the i-th level scanning driving unit GDL(i) also includes a second pre-pull-down module 60, which is electrically connected to the control end of the second switch tube T2. The second pre-pull-down module 60 is used to respond to the pre-pull-down signal corresponding to the scanning driving unit GDL(i) at this level, and pull the control end of the second switch tube T2 to a low level, thereby turning off the second switch tube T2.

[0049] In this way, before the start signal of the i-th level scan driving unit GDL(i) arrives, the control end of the second switch tube T2 can be pulled down to a low level in advance to turn off the second switch tube T2 in advance. In this way, there is no need to set the size of the third switch tube T3 to be particularly large, or even the lower tube can be cancelled. In this way, the area of ​​the scan driving circuit 1 can be further reduced.

[0050] In some embodiments, the first pre-pull-down module 40 includes a fifth switch tube T5, and the fifth switch tube T5 includes a first connection end, a second connection end and a control end. The first connection end of the fifth switch tube T5 is electrically connected to the pull-up control node Q(i), the second connection end of the fifth switch tube T5 is used to receive the low-level voltage VGL, and the control end of the fifth switch tube T5 is used to receive the pre-pull-down signal corresponding to the scan driving unit at this level.

[0051] When working, the fifth switch tube T5 is turned on in response to the pre-pull-down signal corresponding to the scan driving unit at this stage, thereby pulling the pull-down control node Qb(i) down to a low level.

[0052] In some embodiments, the second pre-pull-down module 60 includes a sixth switch tube T6, which includes a first connection end, a second connection end and a control end. The first connection end of the sixth switch tube T6 is electrically connected to the control end of the second switch tube T2, the second connection end of the sixth switch tube T6 is used to receive the low-level voltage VGL, and the control end of the sixth switch tube T6 is used to receive a pre-pull-down signal corresponding to the scan driving unit at this level.

[0053] During operation, the sixth switch tube T6 is turned on in response to the pre-pull-down signal corresponding to the scan driving unit at this stage, thereby pulling down the control end of the second switch tube T2 to a low level, thereby turning off the second switch tube T2.

[0054] In some embodiments, a ratio of a channel width-to-length ratio of the fourth switch transistor T4 to a channel width-to-length ratio of the second switch transistor T2 is less than 2.

[0055] In the prior art, the channel width-to-length ratio of the second switch tube T2 is usually 24μm / 3μm, and the channel width-to-length ratio of the fourth switch tube T4 is usually 400μm / 3μm, that is, the ratio between the channel width-to-length ratio of the fourth switch tube T4 and the channel width-to-length ratio of the second switch tube T2 is 400 / 24. In contrast, in the embodiment of the present application, since the first pre-pull-down module 40 receives the corresponding pre-pull-down signal to pull the pull-down control node down to a low level before the pull-up module 10 in the current level scan driving unit pulls the pull-up control node up to a high level, the ratio between the channel width-to-length ratio of the fourth switch tube T4 and the channel width-to-length ratio of the second switch tube T2 can be less than 2, thereby greatly reducing the size of the fourth switch tube T4. For example, in the embodiment of the present application, the channel width-to-length ratio of the second switch tube T2 is 24 μm / 3 μm, and the channel width-to-length ratio of the fourth switch tube T4 is 40 μm / 3 μm, then the ratio between the channel width-to-length ratio of the fourth switch tube T4 and the channel width-to-length ratio of the second switch tube T2 is 40 / 24.

[0056] In some embodiments, a ratio of a channel width-to-length ratio of the third switch transistor T3 to a channel width-to-length ratio of the first switch transistor T1 is less than 2.

[0057] In the prior art, the channel width-to-length ratio of the first switch tube T1 is usually 24μm / 3μm, and the channel width-to-length ratio of the third switch tube T3 is usually 200μm / 3μm, that is, the ratio between the channel width-to-length ratio of the third switch tube T3 and the channel width-to-length ratio of the first switch tube T1 is 200 / 24. In contrast, in the embodiment of the present application, since the second pre-pull-down module 60 receives the corresponding pre-pull-down signal to pull down the control end of the first switch tube T1 to a low level before the pull-up module 10 in the current level scan driving unit pulls up the pull-up control node to a high level, the ratio between the channel width-to-length ratio of the third switch tube T3 and the channel width-to-length ratio of the first switch tube T1 can be less than 2, thereby greatly reducing the size of the third switch tube T3. For example, in the embodiment of the present application, the channel width-to-length ratio of the first switch tube T1 is 24 μm / 3 μm, and the channel width-to-length ratio of the third switch tube T3 is 40 μm / 3 μm, then the ratio between the channel width-to-length ratio of the third switch tube T3 and the channel width-to-length ratio of the first switch tube T1 is 40 / 24.

[0058] In some embodiments, the pull-down maintaining module 30 includes a seventh switch tube T7 and an eighth switch tube T8, the seventh switch tube T7 includes a first connection end, a second connection end and a control end, the first connection end of the seventh switch tube T7 is electrically connected to the pull-up control node Q(i), and the second connection end of the seventh switch tube T7 is used to receive the low-level voltage VGL.

[0059] The eighth switch tube T8 includes a first connection end, a second connection end and a control end. The first connection end of the eighth switch tube T8 is electrically connected to the scan signal output end G(i), and the second connection end of the eighth switch tube T8 is used to receive a low-level voltage VGL.

[0060] When the pull-down control node Qb(i) is at a high level, the pull-down maintaining module 30 works, the seventh switch tube T7 is turned on to maintain the pull-up control node Q(i) at a low level, and the eighth switch tube T8 is turned on to maintain the scan signal output terminal G(i) at a low level. When the pull-down control node Qb(i) is at a low level, the pull-down maintaining module 30 does not work, and the seventh switch tube T7 and the eighth switch tube T8 are both turned off.

[0061] In some embodiments, the pull-up module 10 includes a ninth switch tube T9, which includes a first connection end, a second connection end and a control end. The first connection end of the ninth switch tube T9 is used to receive a high-level voltage VGH, the second connection end of the ninth switch tube T9 is electrically connected to the pull-up control node Q(i), and the control end of the ninth switch tube T9 is used to receive a start signal corresponding to the scan driving unit at this level.

[0062] When working, the ninth switch tube T9 is turned on in response to the start signal corresponding to the scan driving unit at this stage, and pulls up the pull-up control node Q(i) to a high level.

[0063] In some embodiments, the output module 20 includes a tenth switch tube T10, the tenth switch tube T10 includes a first connection end, a second connection end and a control end, the first connection end of the tenth switch tube T10 is electrically connected to the clock signal input end Clk, the second connection end of the tenth switch tube T10 is electrically connected to the scan signal output end G(i). The control end of the tenth switch tube T10 is electrically connected to the pull-up control node Q(i).

[0064] In some embodiments, the output module 20 further includes a capacitor C, and the capacitor C is electrically connected between the second connection terminal of the tenth switch tube T10 and the control terminal of the tenth switch tube T10.

[0065] During operation, when the pull-up control node Q(i) is at a high level, the tenth switch tube T10 is turned on and outputs a scan signal based on the received clock signal.

[0066] In some embodiments, the i-th-stage scan driving unit GDL(i) further includes an eleventh switch tube T11 , a twelfth switch tube T12 , and a thirteenth switch tube T13 .

[0067] The eleventh switch tube T11 includes a first connection end, a second connection end and a control end. The first connection end of the eleventh switch tube T11 is electrically connected to the pull-up control node Q(i), and the second connection end of the eleventh switch tube T11 is used to receive the low-level voltage VGL. The control end of the eleventh switch tube T11 is used to receive and respond to the pull-down signal corresponding to the current-level scan driving unit to pull the pull-up control node Q(i) down to a low level.

[0068] The twelfth switch tube T12 includes a first connection end, a second connection end and a control end, wherein the first connection end of the twelfth switch tube T12 is electrically connected to the pull-up control node Q(i), and the second connection end of the twelfth switch tube T12 is used to receive the low-level voltage VGL. The control end of the twelfth switch tube T12 is used to receive and pull down the pull-up control node Q(i) to a low level in response to a reset signal RST.

[0069] The thirteenth switch tube T13 includes a first connection end, a second connection end and a control end. The first connection end of the thirteenth switch tube T13 is electrically connected to the scan signal output end G(i). The second connection end of the thirteenth switch tube T13 is used to receive the low-level voltage VGL. The control end of the thirteenth switch tube T13 is used to receive and pull down the scan signal output end G(i) to a low level in response to a reset signal RST.

[0070] like Figure 3 As shown, in the second group of control subunits, the pull-down maintaining module 30' includes a seventh switch tube T7' and an eighth switch tube T8', the first pre-pull-down module 40' includes a fifth switch tube T5', the inverter circuit 50' includes a second low-frequency signal input terminal VDDN, a first switch tube T1', a second switch tube T2', a third switch tube T3' and a fourth switch tube T4', and the second pre-pull-down module 60' includes a sixth switch tube T6'. Since the circuit structure of the second group of control subunits is the same as that of the first group of control subunits, they are not repeated here.

[0071] It should be noted that, in the embodiment of the present application, the switch tubes in the scan drive circuit 1 (including the first switch tube T1 to the thirteenth switch tube T13) all use high-level conductive TFTs (Thin Film Transistors), that is, N-type TFTs. When the gate of the N-type TFT is input with a high level, the source and drain are turned on. Since the source and drain of the transistor used are symmetrical, there is no difference between the source and drain. In the embodiment of the present application, in order to distinguish the source and drain of the transistor, one of the electrodes is called the first connection terminal, the other electrode is called the second connection terminal, and the gate is called the control terminal. It can be imagined that the use of P-type transistors is something that a person skilled in the art can easily think of without creative work, and therefore it is also within the scope of protection of the embodiments of the present disclosure. Of course, in other embodiments, other types of switch tubes, such as triodes, may also be used.

[0072] Please refer again Figure 1 Based on the same technical concept, the present application also provides a display panel 100, which includes m rows of pixel units P and the scan driving circuit 1 described in any of the above embodiments.

[0073] The scan driving circuit 1 is disposed in a non-display area 101 of the display panel 100 , and the m rows of pixel units P are disposed in a display area 102 of the display panel 100 .

[0074] The display panel 100 provided by the present application is provided with a first pre-pull-down module in each level of the scanning driving unit, and the first pre-pull-down module receives a corresponding pre-pull-down signal to pull down the pull-down control node to a low level before the pull-up module in the scanning driving unit of the same level pulls up the pull-up control node to a high level. Compared with the method in the prior art in which the pull-down control node is pulled down to a low level by using the high level of the pull-up control node after the pull-up control node is charged to a high level by an inverter circuit, the first pre-pull-down module pulls down the pull-down control node to a low level in advance before the pull-up module charges the pull-up control node, and the pull-down time is advanced. Therefore, it is not necessary to set the size of the lower tube in the inverter circuit to be particularly large, or even to cancel the lower tube. In this way, the area of ​​the scanning driving circuit 1 can be reduced, which is beneficial to the narrow frame design of the display panel 100.

[0075] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A scanning driving circuit, applied to a display panel, the display panel comprising m rows of pixel units arranged in sequence; the scanning driving circuit comprising m levels of cascaded scanning driving units, the m levels of scanning driving units corresponding one to one to the m rows of pixel units, characterized in that: Each level of the scanning driving unit comprises: A clock signal input terminal, used to receive a clock signal corresponding to the scanning driving unit at this level; Scan signal output terminal; Pull up control node; Pull down the control node; A pull-up module, electrically connected to the pull-up control node, and the pull-up module pulls up the pull-up control node to a high level in response to a start signal corresponding to the scan driving unit at this level; A first pre-pull-down module is electrically connected to the pull-down control node, and the first pre-pull-down module pulls the pull-down control node down to a low level in response to a pre-pull-down signal corresponding to the scan driving unit at this level; a pull-down maintaining module, electrically connected to both the pull-down control node and the pull-up control node, the pull-down maintaining module being used to work when the pull-down control node is at a high level and pull the pull-up control node down to a low level, and not work when the pull-down control node is at a low level; and an output module, electrically connected to the clock signal input terminal, the pull-up control node and the scan signal output terminal, the output module being configured to output a scan signal through the scan signal output terminal based on the clock signal received by the clock signal input terminal when the pull-up control node is at a high level; Among them, the start signal corresponding to the i-th level scan driving unit is the scan signal output by the in-th level scan driving unit, and the pre-pull-down signal corresponding to the i-th level scan driving unit is the level signal output by the pull-up control node in the in-1-th level scan driving unit; i, m and n are all positive integers, i≤m, 1≤in-1.

2. The scanning driving circuit according to claim 1, characterized in that: Each level of the scan driving unit also includes an inverter circuit, which is electrically connected to the pull-up control node and the pull-down control node. The inverter circuit is used to control the pull-down maintaining module to pull down and maintain the scan signal output end and the pull-up control node at a low level after the pull-up control node is pulled down to a low level.

3. The scanning driving circuit according to claim 2, characterized in that: The inverter circuit comprises: A low-frequency signal input terminal, used for receiving a low-frequency signal; A first switch tube, comprising a first connection end, a second connection end and a control end, wherein the first connection end and the control end of the first switch tube are both electrically connected to the low-frequency signal input end; A second switch tube, comprising a first connection end, a second connection end and a control end, wherein the first connection end of the second switch tube is electrically connected to the low-frequency signal input end, and the control end of the second switch tube is electrically connected to the second connection end of the first switch tube; A third switch tube, comprising a first connection end, a second connection end and a control end, wherein the first connection end of the third switch tube is electrically connected to the second connection end of the first switch tube, the second connection end of the third switch tube is used to receive a low-level voltage, and the control end of the third switch tube is electrically connected to the pull-up control node; and The fourth switch tube includes a first connection end, a second connection end and a control end. The first connection end of the fourth switch tube is electrically connected to the second connection end of the second switch tube. The second connection end of the fourth switch tube is used to receive the low-level voltage. The control end of the fourth switch tube is electrically connected to the pull-up control node.

4. The scanning driving circuit according to claim 3, characterized in that: Each level of the scan driving unit also includes a second pre-pull-down module, which is electrically connected to the control end of the second switch tube. The second pre-pull-down module is used to respond to the pre-pull-down signal corresponding to the scan driving unit at this level, and pull the control end of the second switch tube to a low level, thereby turning off the second switch tube.

5. The scanning driving circuit according to claim 1, wherein: The first pre-pull-down module includes a fifth switch tube, which includes a first connection end, a second connection end and a control end. The first connection end of the fifth switch tube is electrically connected to the pull-up control node, the second connection end of the fifth switch tube is used to receive a low-level voltage, and the control end of the fifth switch tube is used to receive a pre-pull-down signal corresponding to the scan driving unit at this level.

6. The scanning driving circuit according to claim 4, characterized in that: The second pre-pull-down module includes a sixth switch tube, which includes a first connection end, a second connection end and a control end. The first connection end of the sixth switch tube is electrically connected to the control end of the second switch tube, the second connection end of the sixth switch tube is used to receive the low-level voltage, and the control end of the sixth switch tube is used to receive the pre-pull-down signal corresponding to the scan driving unit at this level.

7. The scanning driving circuit according to claim 4, characterized in that: A ratio of a channel width-to-length ratio of the fourth switch tube to a channel width-to-length ratio of the second switch tube is less than 2.

8. The scanning driving circuit according to claim 4, characterized in that: A ratio of a channel width-to-length ratio of the third switch tube to a channel width-to-length ratio of the first switch tube is less than 2.

9. The scanning driving circuit according to claim 1, wherein: The pull-down maintaining module comprises: a seventh switch tube, comprising a first connection end, a second connection end and a control end, wherein the first connection end of the seventh switch tube is electrically connected to the pull-up control node, the second connection end of the seventh switch tube is used to receive a low-level voltage, and the control end of the seventh switch tube is electrically connected to the pull-down control node; The eighth switch tube includes a first connection end, a second connection end and a control end. The first connection end of the eighth switch tube is electrically connected to the scan signal output end, the second connection end of the eighth switch tube is used to receive a low-level voltage, and the control end of the eighth switch tube is electrically connected to the pull-down control node.

10. A display panel, characterized in that: The display panel comprises: m rows of pixel units; and A scan drive circuit as claimed in any one of claims 1 to 9.

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