CN104503113A - Liquid crystal display panel and display device - Google Patents

Abstract

The invention provides a liquid crystal panel and a display device, belonging to the technical field of liquid crystal display, which can solve the problem of residual image displayed by the existing liquid crystal panel. A liquid crystal panel of the present invention, which includes a plurality of common electrode lines, a plurality of data lines and a plurality of gate lines intersecting, a source drive unit, and at least one discharge unit. Pixel units are defined at the intersection positions, the pixel units in each row are connected to the same common electrode line, the source drive unit provides data signals for each of the data lines, and each discharge unit is connected to a data line and a common electrode The line is connected to a control signal line, which is used to make the data line connected to it selectively conduct with the source driving unit or conduct with the common electrode line under the control of the control signal input from the control signal line . The liquid crystal panel of the present invention can effectively release the residual charge, so as to avoid the problem of residual image displayed on the liquid crystal.

Description

Liquid crystal panel and display device

technical field

The invention belongs to the technical field of liquid crystal display, and in particular relates to a liquid crystal panel and a display device.

Background technique

In recent years, liquid crystal displays have become popular and become mainstream display devices in the market due to their advantages such as low operating voltage, low power consumption, low radiation, small space occupation, and thin, light and beautiful appearance. At present, people's requirements for liquid crystal displays are constantly increasing, especially for the display quality of the entire display. Among them, the afterimage problem is one of the most critical factors affecting the display quality of the picture.

A traditional liquid crystal panel is composed of two transparent substrates sandwiching a liquid crystal layer. A plurality of data lines and a plurality of gate lines are formed on one substrate, and the data lines and the gate lines are intersected to define a plurality of pixel units, each of which includes a switch control element (such as a switch transistor) and a pixel portion ( Including liquid crystal capacitor and storage capacitor), the switch control element is used to control the opening and closing of the pixel part (that is, the charging and discharging of the storage capacitor and the liquid crystal capacitor), so as to control the liquid crystal in the liquid crystal display panel under the action of the electric field formed by the liquid crystal capacitor. deflection, and then realize the image display function of the liquid crystal panel. Wherein, the two polar plates of the storage capacitor are usually composed of a pixel electrode and a common electrode, and the two polar plates of the liquid crystal capacitor are usually composed of a liquid crystal cell.

As shown in Figures 1 and 2, the gate of the switching transistor TFT is connected to the gate line 1, the source of the switching transistor TFT is connected to the data line 2, and the drain of the switching transistor TFT is connected to one end of the storage capacitor Cst and the liquid crystal capacitor Clc, The other ends of the storage capacitor Cst and the liquid crystal capacitor Clc are connected to the common electrode line 3 . When displaying, the scanning signal Vg(n)/Vg(n-1) output on the gate line 1 turns on the switching transistor TFT, and the data signal Vdata on the data line 2 can be transmitted from the source of the switching transistor TFT to the switching transistor TFT The drain electrode charges the storage capacitor Cst and the liquid crystal capacitor Clc, and an electric field that deflects the liquid crystal can be formed between the two plates of the charged liquid crystal capacitor Clc, thereby realizing the image display of the liquid crystal panel.

The electric field that deflects the liquid crystal is directional. If the direction of the electric field is not changed, problems such as DC blocking effect (the voltage difference is mainly distributed on the alignment layer) and liquid crystal fatigue will occur. Therefore, it is necessary to frequently change the direction of the electric field formed by the liquid crystal capacitor Clc. That is, it is necessary to invert the polarity of the electric field, and the polarity inversion includes frame inversion, dot inversion, row inversion and column inversion. During the polarity reversal process of the electric field, due to the leakage of the switching transistor TFT and the parasitic capacitance Cgs on the liquid crystal capacitance Clc (that is, as shown in the timing diagram of the pixel electrode voltage Vc in Figure 2, when a certain row of pixel units is scanned Afterwards, at this time, the potential on the gate line 1 that selects the pixel unit in this row changes from a high potential to a low potential (or from a low potential to a high potential), and the pixel electrode voltage Vc will jump at this moment, that is, a jump The voltage is ΔVc, which also produces the crosstalk of the parasitic capacitance Cgs), which will cause the positive and negative charges on the two plates of the liquid crystal capacitor Clc to not be completely offset, resulting in a DC residual charge on a certain plate of the liquid crystal capacitor Clc (that is, DC The generation of residual charge), as shown in Figure 2, the accumulation of this part of the residual charge will make the liquid crystal orientation unable to return to the initial state and form an afterimage.

Contents of the invention

The technical problem to be solved by the present invention includes, aiming at the above-mentioned problems existing in the existing liquid crystal panel, to provide a liquid crystal panel and a display device which can release the residual charge in the pixel unit to improve the display effect.

The technical solution adopted to solve the technical problem of the present invention is a liquid crystal panel, which includes a plurality of common electrode lines, a plurality of data lines and a plurality of gate lines intersecting, and a source drive unit, and the gate lines and the gate lines Pixel units are defined at the intersection positions of the data lines, the pixel units in each row are connected to the same common electrode line, the source drive unit provides data signals for each of the data lines, and the liquid crystal panel also includes at least one discharge unit,

Each of the discharge cells is connected to a data line, a common electrode line and a control signal line, and is used to make the data line connected to it selectively connect with the source under the control of the control signal input from the control signal line. The electrode driving unit is turned on or connected to the common electrode line.

Preferably, the liquid crystal panel includes a plurality of discharge cells, and each discharge cell corresponds to a data line.

Preferably, the common electrode lines connected to the discharge cells are any one or more of the plurality of common electrode lines.

Further preferably, the common electrode line connected to the discharge cells is the first common electrode line among the plurality of common electrode lines.

Preferably, the gate lines are scanned row by row to complete the display of each frame, and after scanning 60 frames, the discharge unit is controlled by the control signal input on the control signal line , making the data line connected thereto conduct with the common electrode line.

It is further preferred that, under the control of the control signal input on the control signal line, the discharge unit makes the data line connected to it and the common electrode line conductive for a period of time for scanning one frame of picture. time.

Preferably, the discharge unit includes a first transistor and a second transistor; wherein, one of the first transistor and the second transistor is an N-type transistor, and the other is a P-type transistor;

The first pole of the first transistor is connected to the source driving unit, the second pole is connected to the data line and the first pole of the second transistor, and the control pole is connected to the gate of the second transistor and the A control signal line, the second electrode of the second transistor is connected to the common electrode line.

Preferably, the pixel unit at least includes a switching transistor, a liquid crystal capacitor and a storage capacitor;

The first pole of the switching transistor is connected to the data line, the second pole is connected to the first end of the storage capacitor and the liquid crystal capacitor, the control electrode is connected to the gate line, and the second end of the storage capacitor and the liquid crystal capacitor is connected to the common electrode line.

The technical solution adopted to solve the technical problem of the present invention is a display device, which includes the above-mentioned liquid crystal panel.

The present invention has following beneficial effect:

Since at least one discharge unit is added in the liquid crystal panel of the present invention, after the discharge unit conducts the data line and the source drive unit to display several frames of pictures, the discharge unit conducts the data line and the common electrode line, and the liquid crystal The two ends of the capacitor and the two ends of the storage capacitor are short-circuited to form a short-circuit ring, and the charges at both ends of the liquid crystal capacitor and the storage capacitor are neutralized to eliminate the residual charge in the liquid crystal capacitor and the storage capacitor, so that the display effect of the liquid crystal panel is better .

Description of drawings

FIG. 1 is a schematic diagram of a pixel unit of an existing liquid crystal panel;

FIG. 2 is a schematic diagram of positive and negative driving of an existing liquid crystal panel;

Fig. 3 is the schematic diagram of the liquid crystal panel of embodiment 1 of the present invention;

4 is a timing diagram when the liquid crystal panel of Embodiment 1 of the present invention displays normally;

FIG. 5 is a timing diagram when the charge of the liquid crystal panel of Embodiment 1 of the present invention is released;

FIG. 6 is a schematic structural diagram of a discharge cell in a liquid crystal panel according to Embodiment 1 of the present invention.

Reference signs are: 1. gate line; 2. data line; 3. common electrode line; 4. source drive unit; 5. discharge unit; 6. control line signal line.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

As shown in Figure 3, the present embodiment provides a liquid crystal panel, which includes: a plurality of common electrode lines 3, a plurality of gate lines 1 and a plurality of data lines 2 intersecting, a source drive unit 4 and at least one discharge unit 5. A pixel unit is defined at the crossing position of the gate line 1 and the data line 2, the pixel unit in each row is connected to the same common electrode line 3, and the source driving unit 4 provides data for each of the data lines 2 The signal Vdata, each of the discharge cells 5 and a data line 2, a common electrode line 3 and a control signal line 6, is used to make the data connected to it under the control of the control signal SEL input from the control signal line 6. The line 2 is selectively connected to the source driving unit 4 or to the common electrode line 3 .

Those skilled in the art can understand that, in a liquid crystal display panel, each pixel unit includes at least a switching transistor TFT, a liquid crystal capacitor Clc (composed of a liquid crystal cell) and a storage capacitor Cst (composed of a pixel electrode and a common electrode); The first pole of the switching transistor TFT is connected to the data line 2, the second pole is connected to the first end of the storage capacitor Cst and the liquid crystal capacitor Clc, the control electrode is connected to the gate line 1, and the second terminal of the storage capacitor Cst and the liquid crystal capacitor Clc terminal connected to the common electrode line 3. Due to the leakage of the switching transistor TFT and the crosstalk of the parasitic capacitance on the liquid crystal capacitor Clc, the positive and negative charges on the two plates of the liquid crystal capacitor Clc cannot be completely offset, resulting in a DC residual charge on a certain plate of the liquid crystal capacitor Clc (i.e. The generation of DC residual charge), the accumulation of this part of the residual charge will make the liquid crystal orientation unable to return to the initial state, forming an afterimage. However, at least one discharge unit 5 is added to the liquid crystal panel of this embodiment. Therefore, when the discharge unit 5 conducts the data line 2 and the source drive unit 4 to display several frames of pictures, the discharge unit 5 connects the data line 2 to the source drive unit 4. The common electrode line 3 is turned on, that is, the two ends of the liquid crystal capacitor Clc and the two ends of the storage capacitor Cst are short-circuited to form a short circuit, the charges at the two ends of the liquid crystal capacitor Clc and the storage capacitor Cst are neutralized, and the liquid crystal capacitor Clc and the storage capacitor are eliminated. The charge remaining in Cst makes the display effect of the liquid crystal panel better.

It can be understood that the liquid crystal panel of this embodiment also includes a gate driving unit, which is used to provide gate scanning signals Vg(n) for each gate line 1, so as to gate each gate line row by row when performing picture display. 1; Of course, those skilled in the art should also know that when the liquid crystal displays the display panel, the common voltage Vcom applied to the common electrodes of each pixel unit is the same, so all the common electrode lines 3 are connected together of.

At the same time, it should be noted that "the data line 2 selectively conducts with the source driver unit 4 or with the common electrode line 3" in this embodiment means that during normal display, The discharge unit 5 conducts the data line 2 and the source drive unit 4 under the control of the control signal SEL. At this time, the source drive unit 4 transmits the data line 2 to the data line 2 for displaying the screen; After displaying several frames of pictures, the discharge unit 5 conducts the data line 2 and the common electrode line 3 under the control of the control signal SEL (the conduction time is the time for scanning one frame of pictures), so that the pixel unit connected to the discharge unit 5 The charge accumulated in the battery can be fully released, thereby avoiding the afterimage problem of the liquid crystal display panel.

As a preferred manner in this embodiment, a plurality of discharge units 5 are provided in the liquid crystal panel, and each discharge unit 5 corresponds to one data line 2 . So that the residual charge in each pixel unit in the display panel can be fully released, so as to ensure a better display effect of the liquid crystal panel.

Preferably, the common electrode line 3 connected to the discharge unit 5 is any one or more of the plurality of common electrode lines 3 . The reason for this setting is that each common electrode line 3 is connected together, so no matter which common electrode line 3 is connected to the common electrode line 3 connected to the discharge unit 5, or with multiple common electrode lines 3, or even It is all possible to connect with all the common electrode lines 3, all of which can be short-circuited with the data line 2 under the control of the discharge unit 5, so that the residual charges in each pixel unit in the display panel can be fully released, thereby ensuring the liquid crystal The display effect of the panel is better. Further preferably, the common electrode line 3 connected to the discharge unit 5 is the first common electrode line 3 in the plurality of common electrode lines 3, at this time, the area of the display area occupied by the discharge unit 5 in the display panel can be reduced , thereby increasing the aperture ratio of the display panel. It should be noted that the common electrode lines 3 in the display panel are generally arranged parallel to the gate lines 1 , and the above-mentioned first common electrode line 3 refers to the common electrode line 3 connected to the first row of pixel units.

Preferably, the gate lines 1 are scanned row by row to complete the display of each frame, and after each scan of 60 frames, the control signal SEL input by the discharge unit 5 on the control signal line 6 Under the control of , make the data line 2 connected thereto conduct with the common electrode line 3 . That is, every 60 frames of pictures are displayed at intervals to release the residual charge on the LCD panel, so as to avoid the increase of the screen display at any time, and the increase of the residual charge, which will cause the problem of afterimage on the LCD panel. Of course, it can also be set to discharge the residual charge of the liquid crystal panel after displaying a certain frame of pictures at intervals according to specific conditions.

Further preferably, under the control of the control signal SEL input on the control signal line 6, the discharge unit 5 makes the data line 2 connected to it and the common electrode line 3 conductive for a time of scanning one frame of picture. At this time, the residual charge of the entire liquid crystal panel can be fully released.

Preferably, in the liquid crystal panel in this embodiment, the discharge unit 5 adopts a switch logic device, and the switch logic device is a selector, which can selectively connect the data line 2 with the source drive unit 4 or with the source drive unit 4 in the control line of the control signal. The common electrode line 3 is turned on.

In order to express the inventive intent of this embodiment more clearly, description will be made in conjunction with FIG. 3 .

The liquid crystal panel includes a plurality of gate lines 1 and a plurality of data lines 2 arranged crosswise, a plurality of common electrode lines 3 arranged in parallel with the gate lines 1, a source driving unit 4 connected to each data line 2, and a data line 2 A plurality of discharge cells 5 in one-to-one correspondence, used to control the control signal lines 6 of the plurality of discharge cells 5, defines pixel units at the crossing positions of the gate lines 1 and the data lines 2, and each pixel unit includes a switching transistor TFT , the storage capacitor Cst and the liquid crystal capacitor Clc, wherein the first pole of the switching transistor TFT is connected to the data line 2, the second pole is connected to the first end of the storage capacitor Cst and the liquid crystal capacitor Clc, the control electrode is connected to the gate line 1, and the storage The second ends of the capacitor Cst and the liquid crystal capacitor Clc are connected to the common electrode line 3 .

The specific work of the LCD panel is as follows:

When each frame is displayed normally, as shown in Figure 4, when the first frame is scanned, the frame start signal STV is input to the gate line 1 of the first row, and then the gate scan signal is input to the gate lines on the display panel CPV, input a control signal SEL (for example, a logic high level signal) to the control signal line 6, to control each discharge unit 5 to electrically connect the data line 2 to the source driving unit 4, so that the source driving unit 4 The output data signal Vdata is transmitted to the pixel units connected to each data line 2 through the corresponding data line 2 . At this time, the electric field that deflects the liquid crystal is directional. If the direction of the electric field is not changed, problems such as DC blocking effect (the voltage difference is mainly distributed on the alignment layer) and liquid crystal fatigue will occur. Therefore, it is necessary to frequently change the electric field formed by the liquid crystal capacitor Clc In other words, the polarity of the electric field needs to be reversed, and the polarity reversal includes frame reversal, dot reversal, row reversal and column reversal. During the polarity reversal process of the electric field, due to the leakage of the switching transistor TFT and the crosstalk of the parasitic capacitance on the liquid crystal capacitor Clc, the positive and negative charges on the two plates of the liquid crystal capacitor Clc cannot be completely offset, resulting in the liquid crystal capacitor Clc The generation of DC residual charge (that is, DC residual charge) on a certain plate. Therefore, after displaying a picture of a certain frame, as shown in FIG. 5 , the signals on each gate line are still the same as during normal scanning, and another control signal SEL (for example, a logic low level signal) is input to the control signal line 6 , to control each discharge unit 5 to electrically connect the data line 2 to the common electrode line 3 of the first row, the two ends of the liquid crystal capacitor Clc and the two ends of the storage capacitor Cst are short-circuited to form a short circuit, that is, the data line The data signal Vdata is equal to the voltage Vcom on the common electrode line, the charges at both ends of the liquid crystal capacitor Clc and the storage capacitor Cst are neutralized, and the residual charges in the liquid crystal capacitor Clc and the storage capacitor Cst are eliminated, so that the display effect of the liquid crystal panel is better.

As a preferred implementation of this embodiment, as shown in Figure 6, the discharge unit 5 includes a first transistor and a second transistor; wherein, one of the first transistor and the second transistor is an N-type transistor, and the other It is a P-type transistor; the first pole of the first transistor is connected to the source driving unit 4, the second pole is connected to the data line 2 and the first pole of the second transistor, and the gate is connected to the second The gate of the transistor is connected to the control signal line 6 , and the second electrode of the second transistor is connected to the common electrode line 3 .

This kind of discharge unit has a simple structure and is easy to implement.

Specifically, the first transistor is an N-type transistor, and the second transistor is a P-type transistor as an example for description.

When each frame is displayed normally, the control signal SEL is input to the control signal line 6 as a high-level signal, at this time the first transistor is turned on, the second transistor is turned off, and the source drive unit is electrically connected to the data line 2 , to provide the data signal Vdata for the data line 2 connected thereto. After a certain frame of picture is displayed, the control signal SEL is input to the control signal line 6 as a low-level signal. At this time, the first transistor is turned off, the second transistor is turned on, the data line 2 is electrically connected to the common electrode line 3, and the liquid crystal The two ends of the capacitor Clc and the two ends of the storage capacitor Cst are short-circuited to form a short circuit, the charges at both ends of the liquid crystal capacitor Clc and the storage capacitor Cst are neutralized, and the residual charges in the liquid crystal capacitor Clc and the storage capacitor Cst are eliminated, so that the liquid crystal The display of the panel is better.

It should be noted that, in this embodiment, the discharge unit includes an N-type transistor and a P-type transistor as an example for illustration, but this does not constitute a limitation to the discharge unit in this embodiment. At the same time, the transistor used in the embodiment of the present invention can be a thin film transistor or a field effect transistor or other devices with the same characteristics. Since the source and drain of the transistor used are symmetrical, there is no difference between the source and drain of the transistor. difference. In the embodiment of the present invention, in order to distinguish the source and drain of the transistor, one of them is called the first pole, the other is called the second pole, and the gate is called the control pole. In addition, according to the characteristics of transistors, transistors can be divided into N-type and P-type transistors. In the above-mentioned embodiment, the first transistor is an N-type transistor, and the second transistor is a P-type transistor. The implementation of the P-type transistor and the second transistor being an N-type transistor can be easily imagined by those skilled in the art without any creative efforts, and thus also falls within the protection scope of the embodiments of the present invention.

Example 2:

This embodiment provides a display device, which includes the liquid crystal panel in Embodiment 1.

By using the liquid crystal display panel in Example 1, the residual charge in the display device can be completely released, so that the display device can avoid afterimages and afterimages during startup, shutdown and display, thereby ensuring that the display device display quality.

The display device provided by the present invention may be a liquid crystal display device of any mode such as TN, ADS, IPS, LTPS and the like. The display device can be any product or component with a display function, such as a liquid crystal panel, a liquid crystal TV, a monitor, a mobile phone, a navigator, and the like.

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (9)

1. A liquid crystal panel, comprising a plurality of common electrode lines, a plurality of data lines and a plurality of gate lines intersecting, and a source driver unit, defining pixels at the crossing positions of the gate lines and the data lines unit, the pixel units in each row are connected to the same common electrode line, and the source drive unit provides data signals for each of the data lines, and it is characterized in that the liquid crystal panel further includes at least one discharge unit, Each of the discharge cells is connected to a data line, a common electrode line and a control signal line, and is used to make the data line connected to it selectively connect with the source under the control of the control signal input from the control signal line. The electrode driving unit is turned on or connected to the common electrode line. 2 . The liquid crystal panel according to claim 1 , wherein the liquid crystal panel comprises a plurality of discharge units, and each discharge unit corresponds to one data line. 3. The liquid crystal panel according to claim 1, wherein the common electrode line connected to the discharge unit is any one or more of the plurality of common electrode lines. 4. The liquid crystal panel according to claim 3, wherein the common electrode line connected to the discharge cells is the first common electrode line among the plurality of common electrode lines. 5. The liquid crystal panel according to claim 1, wherein the grid lines are scanned row by row to complete the display of each frame, and after each scan of 60 frames, the discharge unit Under the control of the control signal input on the control signal line, the data line connected thereto is conducted with the common electrode line. 6. The liquid crystal panel according to claim 5, characterized in that, under the control of the control signal input on the control signal line, the discharge unit makes the data line connected to it and the common electrode line The turn-on time is the time for scanning one frame of picture. 7. The liquid crystal panel according to any one of claims 1-6, wherein the discharge unit comprises a first transistor and a second transistor; wherein, one of the first transistor and the second transistor is N type transistor, and the other is a P-type transistor; The first pole of the first transistor is connected to the source driving unit, the second pole is connected to the data line and the first pole of the second transistor, and the control pole is connected to the gate of the second transistor and the A control signal line, the second electrode of the second transistor is connected to the common electrode line. 8. The liquid crystal panel according to claim 1, wherein the pixel unit at least comprises a switching transistor, a liquid crystal capacitor and a storage capacitor; The first pole of the switching transistor is connected to the data line, the second pole is connected to the first end of the storage capacitor and the liquid crystal capacitor, the control electrode is connected to the gate line, and the second end of the storage capacitor and the liquid crystal capacitor is connected to the common electrode line. 9. A display device, characterized in that the display device comprises the liquid crystal panel according to any one of claims 1-8.