KR20120065754A - In-plane switching mode lcd and method of driving the same - Google Patents

Abstract

PURPOSE: An in-plane switching mode liquid crystal display device and a driving method thereof are provided to supply stable common voltage to a liquid crystal panel by compensating common voltage. CONSTITUTION: A liquid crystal panel comprises a plurality of pixels, a plurality of gate lines, a plurality of data lines, and a plurality of common lines. A feedback bar receives detection common voltage passed the liquid crystal panel. A common voltage driving part(600) supplies common voltage to a common wire. A common voltage feedback unit(700) creates compensation common voltage corresponding to the detection common voltage. The common voltage feedback unit transfers the compensation common voltage to the common voltage driving part.

Description

Transverse electric field type liquid crystal display and its driving method {In-Plane Switching Mode LCD and method of driving the same}

The present invention relates to a liquid crystal display device, and more particularly, to a swing of a common voltage of a transverse electric field type liquid crystal display device.

       As the information society develops, the demand for display devices for displaying images is increasing in various forms. Recently, liquid crystal displays (LCDs), plasma display panels (PDPs), organic fields Various flat display devices such as organic light emitting diodes (OLEDs) are being utilized.

Among these flat panel display devices, liquid crystal display devices are widely used because they have advantages of miniaturization, light weight, thinness, and low power driving. On the other hand, an active matrix type liquid crystal display device in which a plurality of pixels are arranged in a matrix form and a switching transistor is formed in each of these pixels is currently widely used.

TN (Twisted Nematic) liquid crystals have been mainly applied to such liquid crystal displays. However, in the TN liquid crystal display, since the liquid crystal is driven by the common electrode and the pixel electrode by the vertical electric field, the light transmittance varies according to the viewing angles of the top, bottom, left and right, and thus there is a limitation in manufacturing a large area liquid crystal display.

In order to solve the above problems, an In-Plane Switching (IPS) liquid crystal display device for driving a liquid crystal by a transverse electric field has been proposed.

The transverse electric field type liquid crystal display device can improve the viewing angle characteristics such as contrast, gray inversion, and color shift, compared to the liquid crystal display device driven by a vertical electric field. It has been widely used in the manufacture of large area liquid crystal displays.

1 is a view schematically showing a liquid crystal panel 20 of a general transverse electric field type liquid crystal display device.

As illustrated, the liquid crystal panel 20 includes a plurality of gate lines GL1 to GL3 extending along a row line direction, and a plurality of data lines extending along a vertical line direction. DL1 to DL3 and a plurality of common wirings CL1 to CL3 are formed on the liquid crystal panel 20 alternately with the gate wiring GL in the lateral direction. The pixel P is defined by the crossing of the gate line GL and the data line DL. In the pixel P, a switching thin film transistor T connected to the gate line GL and the data line DL is formed. The switching thin film transistor T is connected to the pixel electrode. Each pixel P includes a pixel electrode and a common electrode forming a transverse electric field. The common electrode is electrically connected to the common wiring CL. In addition, the common electrode receives a common voltage transferred through the common wiring CL. At this time, one side of the common line CL is connected in common, and the same common voltage is applied through all the common lines CL. A transverse electric field is formed between the pixel electrode and the common electrode to drive the liquid crystal.

The pixel electrode, the common electrode, and the liquid crystal positioned between these electrodes constitute a liquid crystal capacitor Clc. Meanwhile, a storage capacitor Cst is further configured in each pixel P, which stores a data voltage applied to the pixel electrode until the next frame.

A pulse-shaped turn-on voltage, that is, a gate voltage, is sequentially applied to the gate wiring GL. As a result, the switching thin film transistor T is turned on and a data voltage is supplied to the pixel electrode in synchronization with the switching thin film transistor T.

On the other hand, when a constant electric field is continuously applied to the liquid crystal of the liquid crystal panel 20, the liquid crystal deteriorates, resulting in afterimages generated by the DC voltage component. Therefore, in order to prevent degradation of the liquid crystal and to remove the DC voltage component, the data voltage is applied to the high voltage and the low potential voltage repeatedly based on the common voltage. Such a driving method is called an inversion method. . (Hereinafter, for convenience of explanation, the low potential voltage is referred to as a negative (−) (negative polarity) voltage, and the high potential voltage is referred to as a (+) (positive polarity) voltage.)

Inversion driving methods include a frame inversion method, a line inversion method, and a dot inversion method.

Among the inversion driving methods, the dot inversion method has superior suppression against screen distortions such as flicker and crosstalk compared to other inversion methods. It is mainly produced.

2 is an exemplary diagram illustrating a voltage waveform of a pixel P in a dot inversion method.

As shown in FIG. 2, in the dot inversion scheme, the common voltage Vcom is maintained at a constant level of DC voltage. The data voltage Vdata is applied to the pixels P adjacent to each other based on the common voltage Vcom, and the positive voltage and the negative voltage are alternately applied. The data voltage Vdata is set based on the common voltage Vcom every frame unit. The polarity voltage and the negative voltage are applied alternately.

That is, in order to drive the dot inversion method, since the common voltage Vcom is applied at a constant level of constant voltage, the voltage level of the data voltage Vdata must be varied. Therefore, the data voltage Vdata should be applied at a predetermined voltage level or higher than the common voltage Vcom, and the data voltage Vdata should be swinged with positive and negative polarity based on the common voltage Vcom. The power consumption is proportional to the square of the amplitude d of the data voltage Vdata (the difference between the positive voltage and the negative voltage = 2 x liquid crystal driving voltage Vp). Therefore, there is a problem that power consumption increases.

In order to solve the above problems, a transverse electric field type liquid crystal display device inverting and driving the common voltage Vcom has been manufactured.

However, since the common voltage Vcom passes through the liquid crystal panel 20, a common voltage drop occurs due to factors such as resistance formed in the liquid crystal panel 20. By applying, there is a problem that the liquid crystal panel 20 cannot be driven stably.

Accordingly, there is a problem in that the image quality of the liquid crystal panel 20 decreases and power consumption increases.

The present invention has a problem to reproduce a transverse electric field type liquid crystal display device and a driving method thereof capable of improving image quality.

Furthermore, there is a problem in reproducing a transverse electric field type liquid crystal display device and a driving method thereof by compensating for the common voltage, thereby applying a stable common voltage to the liquid crystal panel, thereby reducing power consumption.

In order to achieve the above object, a plurality of pixels are arranged in a matrix form along a plurality of row lines and column lines, each of which includes a pixel electrode and a common electrode forming a switching transistor and a transverse electric field, A plurality of gate lines connected to the pixels positioned in the row lines, each of a plurality of data lines connected to the pixels positioned in the column lines, and each of the plurality of gate lines adjacent to each other in the column lines A liquid crystal panel including a plurality of common wires connected to the common electrodes of the pixels alternately positioned; A feedback bar receiving the detected common voltage passing through the liquid crystal panel; A common voltage driver applying a common voltage to the common wiring; According to an aspect of the present invention, there is provided a liquid crystal display including a common voltage feedback unit configured to generate a compensation common voltage corresponding to the detected common voltage and transfer the compensation common voltage to the common voltage driver.

The common voltage driver and the feedback bar are positioned on the other side with the liquid crystal panel interposed therebetween.

The common wiring, the feedback bar, and the gate wiring are connected to each other.

The common wiring, the feedback bar, and the gate wiring further include a transistor connected to each other, a gate electrode of the transistor is connected to the gate wiring, a source electrode of the transistor is connected to the common wiring, and a drain of the transistor. An electrode is connected to the feedback bar.

The common wiring line may include a front end wiring line connected to a pixel located at a front end line of the adjacent line lines; And a rear end wiring connected to a pixel located at a rear end row line among the neighboring row lines.

The feedback bar is connected to the front end wiring.

The gate wiring is positioned between the front wiring and the rear wiring, and does not overlap each other.

In a liquid crystal display device driving method comprising a liquid crystal panel including a plurality of pixels including a pixel electrode and a common electrode forming a switching transistor and a transverse electric field, each of which is arranged in a matrix form along a plurality of row and column lines. And sequentially applying a gate voltage to a plurality of gate wirings connected to the pixels, each of which is located in the row line; Synchronizing with the application of the gate voltage, applying a data voltage corresponding to a plurality of data wirings, each connected to the pixel at which the column line is located; Applying a plurality of common wires connected to the common electrodes of the pixels alternately positioned in the row lines adjacent to each other in the row lines while inverting the common voltages generated corresponding to the compensation common voltages sequentially; The generating of the compensation common voltage includes: a) detecting a detection common voltage passing through the liquid crystal panel; And b) comparing the common voltage with the detected common voltage.

The common voltage applied to the common line is connected to the common line and is synchronized with a gate voltage applied to a pixel located at a previous row line among neighboring row lines.

The common wiring line may include a front end wiring line connected to a pixel located at a front end line of the adjacent line lines; And a rear end wiring connected to a pixel located at a rear end row line among the neighboring row lines.

The gate wiring is positioned between the front wiring and the rear wiring, and does not overlap each other.

The IPS liquid crystal display according to the present invention drives a plurality of common voltages alternated with each row line and swings a common voltage every frame, thereby reducing power consumption by reducing the amplitude of the data voltage. .

Furthermore, by applying a common voltage that compensates for the common voltage drop caused by passing through the liquid crystal panel, the liquid crystal panel can be driven more stably.

1 is a schematic cross-sectional view showing a conventional transverse electric field type liquid crystal display device
2 is a timing diagram showing a relationship between a common voltage and a data voltage of a conventional transverse electric field type liquid crystal display device.
3 is a schematic cross-sectional view showing a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention.
4 is a schematic cross-sectional view showing pixels of a liquid crystal panel of a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention.
5 is a timing diagram illustrating voltage signals applied to gate wirings and common wirings of a transverse electric field type liquid crystal display according to an exemplary embodiment of the present invention.
6 is a method of applying a data voltage and implementing a screen display of a transverse electric field type liquid crystal display according to an exemplary embodiment of the present invention.
7 is a timing diagram illustrating voltage signals applied to gate wirings and common wirings of a transverse electric field type liquid crystal display according to still another exemplary embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

3 is a view schematically showing a transverse electric field type liquid crystal display device according to an embodiment of the present invention, Figure 4 is a view showing a liquid crystal panel of Figure 3, Figure 5 is a transverse electric field liquid crystal according to an embodiment of the present invention A timing diagram showing voltage signals applied to gate wirings and common wirings of a display device.

As illustrated, the liquid crystal display device 100 according to the embodiment of the present invention includes a liquid crystal panel 200, a feedback bar FB, a backlight 800, and a driving circuit unit D. do.

In the liquid crystal panel 200, a plurality of gate lines GL extending along a row line direction and a plurality of data lines DL extending along a column line direction are positioned. In addition, the liquid crystal panel 200 includes a plurality of common lines CL formed in a dual line form with the gate line GL interposed therebetween in a lateral direction. The gate line GL and the data line DL cross each other to define the pixel P in a matrix form.

Each pixel P includes a switching thin film transistor T, a pixel electrode, a common electrode, a liquid crystal capacitor Clc, and a storage capacitor Cst.

The switching thin film transistor T is formed at an intersection of the gate line GL and the data line DL. In addition, the switching thin film transistors T of the pixels P in the row line are connected to the same gate line GL. The pixel electrode is connected to the switching thin film transistor T, and the common electrode is connected to the corresponding common line CL. The pixel electrode and the common electrode are formed on the same substrate to form a transverse electric field, thereby driving the liquid crystal positioned between them. The liquid crystal capacitor Clc is composed of a pixel electrode, a common electrode, and a liquid crystal positioned between these electrodes. The storage capacitor Cst stores the data voltage applied to the pixel electrode until the next frame.

The feedback bar FB is positioned on one side of the liquid crystal panel 200 to receive the common voltage Vcom passing through the liquid crystal panel 200 from the common wiring CL. To this end, the feedback bar FB may be formed at the other side of the stage where the common voltage Vcom is applied.

In detail, when the common voltage Vcom is applied to one side of the liquid crystal panel 200, the feedback bar FB is formed on the other side of the liquid crystal panel 200.

More specifically with reference to FIG. 1, for example, when the common voltage Vcom is applied to the right side of one side of the liquid crystal panel 200, the feedback bar FB is formed on the left side of the liquid crystal panel 200.

The liquid crystal panel 200 is formed to extend in the column line direction in parallel with the data wiring DL of the liquid crystal panel 200.

The backlight 800 serves to supply light to the liquid crystal panel 200. As the backlight 700, a Cold Cathode Fluorescent Lamp (CCFL), an External Electrode Fluorescent Lamp (EEFL), a Light Emitting Diode (LED), or the like may be used.

The driving circuit unit D may include a timing controller 300, a gate driver 400, a data driver 500, a common voltage driver 600, and a common voltage feedback unit 800.

Here, the timing controller 300 may enable the image data signal RGB, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, the clock signal CLK, and the data enable from an external system such as a TV system or a video card. The control signal TCS, such as the signal DE, is received. Although not shown, such signals may be input through an interface configured in the timing controller 310.

In addition, the timing controller 300 uses the input control signal TCS to control the gate control signal GCS for controlling the gate driver 400 and the data control signal DCS for controlling the data driver 500. Can be generated.

In addition, the timing controller 300 receives the image data signal RGB from an external system, arranges the image data signal RGB, and transmits the image data signal RGB to the data driver 500.

Furthermore, a common control signal CCS for controlling the common voltage driver 600 is generated, and a feedback control signal FCS for controlling the common voltage feedback unit 700 is generated.

The data driver 500 generates a data voltage corresponding to the image data signal RGB in response to the data control signal DCS supplied from the timing controller 300. In addition, the generated data voltage is output to the corresponding data line DL.

Accordingly, the data driver 330 can output the grayscale voltage corresponding to the grayscale level as the data voltage using the gamma voltage to the input image data signal RGB in the digital format. In this way, the data driver 500 outputs the video data signal RGB in digital format as video data in analog format. The data voltage thus output is applied to the corresponding data line DL and input to the corresponding pixel P.

The gate driver 400 may sequentially apply gate voltages to the plurality of gate lines GL in response to the gate control signal GCS. For example, a plurality of gate lines GL are sequentially selected during each frame, and a gate voltage is output to the selected gate lines GL. By the gate voltage, the switching thin film transistor T positioned in the corresponding row line is turned on. On the other hand, the turn-off voltage is supplied to the gate line GL until the next frame is scanned, so that the switching thin film transistor T is maintained in the turn-off state.

The gate driver 400 may be manufactured in an IC form and connected to the liquid crystal panel 200 or may be directly formed on the liquid crystal panel 200. The method in which the gate driver 400 is directly formed in the liquid crystal panel 200 is called a GIP (Gate In Panel) method. In such a GIP method, in the process of forming an array element including the switching thin film transistor T, the gate wiring GL, and the data wiring DL in the liquid crystal panel 200, the gate driver 400 may include a liquid crystal panel ( 200) can be formed directly.

The common voltage driver 600 outputs the common voltage Vcom corresponding to the common wiring CL in response to the common control signal CCS.

At this time, the common voltage feedback unit 700 receives the compensation common voltage CVcom, generates a corresponding common voltage Vcom, and outputs the common voltage CL.

The common voltage feedback unit 700 generates a compensation common voltage CVcom for compensating the common voltage Vcom in response to the feedback control signal FCS and transmits the compensation common voltage CVcom to the common voltage driver 600.

At this time, the common voltage feedback unit 700 receives the detection common voltage DVcom from the feedback bar FB and generates a compensation common voltage CVcom corresponding thereto. This will be described in more detail later.

4 and 5, a transverse electric field type liquid crystal display device and a driving method thereof according to the present invention will be described in more detail.

The common line CL is alternately connected to the pixels P positioned in two neighboring row lines in column line units.

For example, the second common line CL2 is connected to the pixels P positioned in the odd (or even) columns of the pixels P of the first row line, and also includes the pixels P of the second row line. It is connected to the pixel P positioned in the even (or odd) -th column among the P's.

Meanwhile, the first common line CL1 is connected to the pixels P which are not connected to the second common line CL2 among the pixels P positioned on the first row line. On the other hand, although not shown, the last common wiring (for example, the n + 1th common wiring) is not connected to the common wiring (for example, the nth common wiring) positioned at the front end of the pixel ( P) is connected.

In the same manner as described above, the connection relationship between the common wiring CL and the pixel P may be achieved.

Hereinafter, the connection relationship between the common wiring CL and the pixel P will be described in detail.

The front end line UL is connected to the pixel P positioned in the front end line of two neighboring row lines. The rear end line LL is connected to the pixel P positioned in the rear end line of two adjacent row lines. For example, the front end UL of the second common line CL2 is connected to the pixels P located in the first row line, and the rear end line LL is the pixels P located in the second row line. Connected with

The front end wiring UL and the rear end wiring LL may be connected to each other at one side. For example, the gate driver 400 may be connected to each other at one side where the gate driver 400 is not formed.

On the other hand, it is preferable that the gate wiring GL and the common wiring CL not overlap each other. Specifically, the gate line GL extends in parallel between the front end wiring UL and the rear end wiring LL, and the portion where the front end wiring UL and the rear end wiring LL are connected is the end of the gate wiring GL. It is preferable to form so as to be spaced apart from the stage.

This is to prevent a capacitive coupling effect occurring at a portion where the gate line GL and the common line CL overlap each other. Through this, the common voltage Vcom distortion may be reduced and the common voltage Vcom may be supplied from the common driver 600 to each common wiring CL.

Meanwhile, the first common wiring CL1 and the last common wiring may not have a double wiring structure such as the front wiring UL and the rear end wiring LL. For example, they may be configured in the form of a single wiring.

5 is a timing diagram of signals for driving a transverse electric field type liquid crystal display according to an exemplary embodiment of the present invention.

In the exemplary embodiment of the present invention, the common voltage Vcom of which polarity is inverted is output to the n + 1th common line in synchronization with the gate voltage applied to the nth (n is natural number) gate line GL. For example, the common voltage Vcom of the second common wiring CL2 is inverted from a negative polarity voltage to a positive polarity voltage in synchronization with a gate voltage applied to the first gate wiring GL1. .

Accordingly, the common voltages Vcom are sequentially output to the common lines CL with a time difference of one horizontal period 1H. In addition, the common voltage Vcom of the common wiring of the rear stage is output to have a polarity opposite to the common voltage Vcom of the common wiring of the preceding stage. For example, after the polarity of the common voltage Vcom of the first common wiring CL1 is inverted from (+) to (-), and after 1H delay, the common voltage Vcom of the second common wiring CL2 The polarity is reversed from (-) to (+). The polarity of the common voltage Vcom of the third common line CL3 is inverted from (+) to (-).

In addition, the polarity of the common voltage Vcom supplied to the common wiring CL is inverted at regular intervals. For example, when the negative common voltage Vcom is applied to the first common line CL1, for example, the positive common voltage Vcom may be applied after one frame.

That is, in the case of the present invention, the common driver 600 sequentially outputs the common voltage Vcom. Therefore, since the coupling duration of the row lines is uniform, there is an effect that the progressive vertical luminance difference is solved.

In addition, the embodiment of the present invention, as shown in Figures 5 and 6, not only the application of the data voltage (Vdata), but also the implementation on the liquid crystal panel is made in a dot inversion method. Thus, the line flicker phenomenon, the horizontal division phenomenon, and the horizontal crosstalk phenomenon generated by the line inversion method can be solved.

Here, the common voltage driver 600 generates a common voltage Vcom in response to the compensation common voltage CVcom and outputs it to the common wiring CL. The compensation common voltage CVcom applies the compensated common voltage Vcom.

Specifically, the common voltage Vcom passing through the liquid crystal panel 200 has a lower value than the common voltage Vcom first applied to the liquid crystal panel 200 due to the resistance of the common wiring CL.

4, for example, when the common voltage Vcom is applied from the right side of the liquid crystal panel 200, the liquid crystal panel 200 is better than the common voltage Vcom on the right side of the liquid crystal panel 200. The common voltage Vcom on the left side of the liquid crystal panel 200 that has passed through has a low value.

That is, the common voltage Vcom of the common voltage output terminal VO has a lower value than the common voltage Vcom of the common voltage input terminal VI. Here, the common voltage input terminal VI represents, for example, the right portion of the liquid crystal panel 200 before the common voltage Vcom passes through the liquid crystal panel 200, and the common voltage output terminal VO represents the common voltage Vcom. Indicates the left side of the liquid crystal panel 200 after passing through the liquid crystal panel 200.

Therefore, the liquid crystal panel 200 must be stably driven by applying the common voltage Vcom by compensating for the drop of the common voltage Vcom generated by passing through the liquid crystal panel 200.

That is, the compensation common voltage CVcom is, for example, a difference voltage between the common voltage input terminal VI and the common voltage output terminal VO, so as to stably drive the liquid crystal panel 200. The voltage is used to compensate for the common voltage drop caused by passing.

Hereinafter, a method of generating the compensation common voltage CVcom will be described in more detail.

First, as described above, the common voltage feedback unit 700 generates a compensation common voltage CVcom for compensating for the common voltage Vcom in response to the feedback control signal FCS and generates the common voltage driver 600. To pass on.

In addition, the common voltage feedback unit 700 receives the detection common voltage DVcom from the feedback bar FB and generates a compensation common voltage CVcom corresponding thereto. Here, the common voltage feedback unit 700 receives the common voltage Vcom applied to the liquid crystal panel 200 from the common voltage driver 800, and generates a compensation common voltage CVcom. It can be used as a voltage.

In more detail, the feedback bar FB is connected to any one of the front end wiring UL and the rear end wiring LL constituting the common wiring CL, and the common voltage passed through the liquid crystal panel 200. (Vcom) is detected. That is, the common voltage of the common voltage output terminal VO is detected to generate the detection common voltage DVcom. .

For example, with reference to FIG. 4, the feedback bar FB may be connected to the shear wiring UL.

In addition, the feedback bar FB is connected to, for example, the gate wiring GL. When a plurality of gate lines GL is sequentially turned on, the common voltage Vcom is applied to the common line CL corresponding to the gate line GL. In response, the common voltage Vcom is applied to the common voltage output terminal VO. This is to detect the voltage Vcom.

That is, when the gate wiring GL is sequentially turned on, the gate voltage GL receives the common voltage Vcom of the corresponding common voltage output terminal VO.

In this case, for example, a transistor may be used to connect the plurality of gate lines GL, the common lines CL, and the feedback bar FB.

Here, a transistor for connecting the gate line GL, the common line CL, and the feedback bar FB is referred to as a first transistor T1.

In detail, the first transistor T1 may be formed on each of the plurality of gate lines GL.

Here, the gate electrode of the first transistor T1 is connected to the gate wiring GL, for example, to turn on the first transistor T1 when a gate high voltage is applied to the gate wiring GL. to be.

The source electrode of the first transistor T1 is connected to the common wiring CL, for example, and the drain electrode of the first transistor T1 is connected to the feedback bar FB, for example. Accordingly, when the plurality of gate lines GL are sequentially turned on, the corresponding first transistor T1 is also turned on, thereby transferring the common voltage Vcom of the common voltage output terminal VO to the feedback bar FB. have.

That is, the feedback bar FB detects the common voltage Vcom passing through the liquid crystal panel 200 and transmits the detected common voltage Vcom to the common voltage feedback unit 700.

Although not shown, the first common wiring CL1, for example, the front end wiring UL is also connected to the feedback bar FB so that the common voltage Vcom passing through the liquid crystal panel 200 is the common voltage feedback unit. Is passed to 700.

The common voltage feedback unit 700 receives the common voltage Vcom from the common voltage driver 600. Here, the common voltage Vcom refers to the common voltage Vcom before passing through the liquid crystal panel 200.

In addition, the common voltage feedback unit 700 corresponds to the common voltage Vcom received from the common voltage driver 600 and the detected common voltage DVcom received from the feedback bar FB. It generates and delivers it to the common voltage driver 700.

Specifically, as described above, the compensation common voltage CVcom is, for example, a difference voltage between the common voltage Vcom of the common voltage input terminal VI and the common voltage Vcom of the common voltage output terminal VO.

Therefore, the compensation common voltage CVcom is generated by, for example, obtaining a difference voltage between the common voltage Vcom received from the common voltage driver 600 and the detection common voltage DVcom received from the feedback bar FB. Can be.

In addition, the generated compensation common voltage CVcom is transferred to the common voltage driver 600.

At this time, the compensation common voltage CVcom is used when the common voltage driver 600 generates the common voltage Vcom of the next frame, for example.

Specifically, for example, the compensation common voltage CVcom is obtained by using the common voltage Vcom of the current frame received from the common voltage driver 600 and the detection common voltage DVcom of the current frame received from the feedback bar FB. ). That is, the degree of common voltage drop generated by the liquid crystal panel 200 is determined. The common voltage drop degree, that is, the compensation common voltage CVcom is used to generate the common voltage Vcom applied in the next frame, thereby compensating the common voltage drop degree.

To this end, for example, the common voltage driver 600 may include a storage memory such as an EEPROM to store the received compensation common voltage CVcom for one frame.

As another example, the common voltage feedback unit 600 may transfer the generated compensation common voltage CVcom to the compensation common voltage CVcom when the common voltage driver 600 generates the common voltage Vcom of the next frame. Can be. To this end, the common voltage feedback unit 600 may include a storage memory such as an EEPROM for storing the generated compensation common voltage Cvom for one frame.

It is apparent to those skilled in the art that the above-described example can be variously designed by the designer as an example of the present invention.

That is, in the embodiment of the present invention, for example, the compensation common voltage CVcom is generated using the common voltage Vcom and the detection compensation voltage DVcom applied to the liquid crystal panel 200 in the current frame. It is used to generate the common voltage Vcom applied to the liquid crystal panel 200 in the next frame.

Hereinafter, a method of applying a data voltage according to an embodiment of the present invention will be described.

In an exemplary embodiment of the present invention, the data voltage and the common voltage Vcom having the inverted polarity are supplied to an arbitrary pixel P. For example, when a positive polarity data voltage is applied to an arbitrary pixel P, a negative common voltage Vcom is applied to the common wiring. When a negative data voltage is applied to an arbitrary pixel P, a common voltage Vcom of positive polarity is applied to the common wiring.

Therefore, the output width of the data driver 500 can be reduced, thereby reducing power consumption.

As another embodiment of the present invention, as shown in FIG. 7, the timing of the common voltage Vcom and the data voltage Vdata may be adjusted to drive the liquid crystal display in a vertical two-dot inversion manner. When driving in the vertical two-dot inversion method, there is an effect that can further improve the power consumption and heat generation.

The embodiment of the present invention described above is an example of the present invention, and variations are possible within the spirit of the present invention. Accordingly, the invention includes modifications of the invention within the scope of the appended claims and their equivalents.

100: transverse electric field type liquid crystal display device 200: liquid crystal panel
400: gate driver 500: data driver 600: common voltage driver
700: common voltage feedback unit
FB: Feedback Bar
CL: Common wiring UL: Front wiring LL: Back wiring
Vcom: Common Voltage Vdata: Data Voltage

Claims (11)

A plurality of pixels disposed in a matrix form along a plurality of row lines and column lines, each pixel including a pixel electrode and a common electrode forming a switching transistor and a transverse electric field, and each of the plurality of pixels connected to the pixels located in the row line; A plurality of gate wirings, a plurality of data wirings each connected to the pixel located in the column line, and a plurality of data wirings connected to the common electrode of the pixel alternately positioned in the column line unit in the adjacent row lines. A liquid crystal panel including a plurality of common wirings connected thereto;
A feedback bar receiving the detected common voltage passing through the liquid crystal panel;
A common voltage driver applying a common voltage to the common wiring;
The common voltage feedback unit generates a compensation common voltage corresponding to the detected common voltage and transfers it to the common voltage driver.
And the liquid crystal display device.
The method of claim 1,
The common voltage driver and the feedback bar are positioned on the other side with the liquid crystal panel interposed therebetween.
LCD display device.
The method of claim 1,
The common wiring, the feedback bar, and the gate wiring are connected to each other.
LCD display device.
The method of claim 3, wherein
The common wiring, the feedback bar and the gate wiring further include a transistor connected to each other,
A gate electrode of the transistor is connected to the gate wiring,
A source electrode of the transistor is connected to the common wiring,
The drain electrode of the transistor is connected to the feedback bar
LCD display device.
The method of claim 1,
The common wiring is,
A front end wiring line connected to a pixel positioned at a front end line of the adjacent line lines;
Back end wirings connected to pixels located in the next end row lines among the adjacent row lines.
Liquid crystal display comprising a.
The method of claim 1,
The feedback bar is connected to the shear wiring
LCD display device.
The method of claim 2,
And the gate wiring is positioned between the front wiring and the rear wiring and do not overlap each other.
In a liquid crystal display device driving method comprising a liquid crystal panel including a plurality of pixels including a pixel electrode and a common electrode forming a switching transistor and a transverse electric field, each of which is arranged in a matrix form along a plurality of row and column lines. In
Sequentially applying gate voltages to a plurality of gate wirings connected to the pixels, each of which is located in the row line;
Synchronizing with the application of the gate voltage, applying a data voltage corresponding to a plurality of data wirings, each connected to the pixel at which the column line is located;
Applying a plurality of common wires connected to the common electrodes of the pixels alternately positioned in the row lines adjacent to each other in the row lines while inverting the common voltages generated corresponding to the compensation common voltages sequentially; Including,
Generating the compensation common voltage,
A) detecting a common voltage detected through the liquid crystal panel;
B) comparing the common voltage and the detected common voltage.
Liquid crystal display driving method.
The method of claim 8,
The common voltage applied to the common wiring is
A gate voltage connected to the common line and synchronized with a gate voltage applied to a pixel located in a row line of a front end of the neighboring row lines
Liquid crystal display driving method.
The method of claim 8,
The common wiring is,
A front end wiring line connected to a pixel positioned at a front end line of the adjacent line lines;
Back end wirings connected to pixels located in the next end row lines among the adjacent row lines.
Liquid crystal display driving method comprising a.
11. The method of claim 10,
And the gate wiring is positioned between the front wiring and the rear wiring and do not overlap each other.

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