KR20070074785A - Liquid crystal display - Google Patents

Abstract

An LCD is provided to widen the reference viewing angle, by disposing two sub-pixel electrodes, to which different data voltages are applied, in one pixel and reducing the distortion of a gamma curve through mutual compensation of the two sub-pixel electrodes. A gate line(22) is formed on a first insulating substrate. A data line(62) crosses the gate line, wherein the data line is insulated from the gate line. A pixel electrode(82) is composed of a first sub-pixel electrode(82a) and a second sub-pixel electrode(82b) to which different voltages are applied. A thin film transistor is connected to the gate line and the data line. A second insulating substrate is disposed to face the first insulting substrate. A common electrode(90) is formed on the second insulating substrate. The common electrode is composed of a first sub-common electrode(90a) and a second sub-common electrode(90b) to which different common voltages are applied correspondingly to the first and second sub-pixel electrodes.

Description

Liquid crystal display

1A is a layout view of a thin film transistor array panel of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 1B is a cross-sectional view of the thin film transistor array panel of FIG. 1A taken along the line Ib-Ib '.

FIG. 1C is a cross-sectional view of the thin film transistor array panel of FIG. 1A taken along the line Ic-Ic ′.

2 is a layout view of a common electrode display panel for a liquid crystal display according to an exemplary embodiment of the present invention.

3A is a layout view of a liquid crystal display including the thin film transistor array panel of FIG. 1A and the common electrode panel of FIG. 2.

3B is a cross-sectional view of the liquid crystal display of FIG. 3A taken along line IIIb-IIIb '.

4 is a circuit diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

5 is a waveform diagram illustrating an output waveform of a data voltage by a liquid crystal display according to an exemplary embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

1: Transmission axis of polarizing plate 10: Insulating substrate

22: gate line 24: gate line end

26 gate electrode 28 sustain electrode line

29a, 29b, 29c, 29d: sustain electrode 40: semiconductor layer

55, 56: ohmic contact layer 62: data line

65 source electrode 66 drain electrode

67: drain electrode extension 68: end of the data line

69: coupling electrode 74, 76, 77, 78: contact hole

82: pixel electrode 82a: first subpixel electrode

82b: second subpixel electrode 83: gap

84: connection member 86: auxiliary gate line end

88: end of auxiliary data line 90: common electrode

90a: first secondary common electrode 90b: second secondary common electrode

91: notch 92: incision

93: gap 94: black matrix

96: insulating substrate 98: color filter

100: thin film transistor display panel 200: common electrode display panel

300: liquid crystal layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a vertically aligned liquid crystal display device in which a pixel is divided into a plurality of domains to obtain a wide viewing angle.

The liquid crystal display is one of the most widely used flat panel display devices. The liquid crystal display includes two display panels on which field generating electrodes such as a pixel electrode and a common electrode are formed, and a liquid crystal layer interposed therebetween. Is applied to generate an electric field in the liquid crystal layer, thereby determining the orientation of liquid crystal molecules in the liquid crystal layer and controlling the polarization of incident light to display an image.

Among them, the vertical alignment mode liquid crystal display in which the long axis of the liquid crystal molecules are arranged perpendicular to the upper and lower display panels without an electric field is applied, and thus a high contrast ratio and a wide reference viewing angle can be easily realized. Here, the reference viewing angle refers to a viewing angle having a contrast ratio of 1:10 or a luminance inversion limit angle between gray levels.

Means for implementing a wide viewing angle in a vertical alignment liquid crystal display include a method of forming a cutout in the pixel electrode and a method of forming a protrusion on the pixel electrode. As described above, since one pixel is divided into a plurality of domains using the cutout or protrusion, the direction in which the liquid crystal molecules are tilted by the cutout or the protrusion may be determined. The reference viewing angle can be widened. Here, the domain refers to a region composed of liquid crystal molecules in which the directors of the liquid crystal molecules are inclined in a specific direction by an electric field formed between the pixel electrode and the common electrode.

In addition, a liquid crystal display of a domain division method for grouping such domains and applying different data voltages to each domain group has been developed. In particular, liquid crystal displays have been developed in which one pixel is divided into two or more domain groups to apply different data voltages using coupling of coupling electrodes between each domain group. In the case of such a liquid crystal display, better visibility and viewing angle are realized by using a difference in liquid crystal capacitance between each domain group.

In the liquid crystal display according to the related art, since different data voltages are applied to each domain group, the same common voltage Vcom is applied to all domain groups, thereby causing flicker and afterimages. . In other words, even if the common voltage is adjusted to improve the characteristics of flicker and the afterimage for a specific domain group, the flicker and the afterimage may become more severe due to the common voltage in other domain groups.

It is an object of the present invention to provide a liquid crystal display device in which flicker and afterimage characteristics can be improved.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes a first insulating substrate, a gate line formed on the first insulating substrate, a data line insulated from and intersecting the gate line, and different voltages. A pixel electrode including the first and second subpixel electrodes to be applied, a thin film transistor connected to the gate line and the data line to apply a voltage to the pixel electrode, and a second insulating substrate facing the first insulating substrate. And a common electrode formed on the second insulating substrate, the common electrode including first and second sub-common electrodes to which different common voltages are applied to correspond to the first and second subpixel electrodes, respectively.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

The liquid crystal display device of the present invention comprises a thin film transistor array panel having a thin film transistor defined by a gate line and a data line, a common electrode panel facing the thin film transistor array panel and having a common electrode, and between the thin film transistor array panel and the common electrode display panel. The liquid crystal layer includes a liquid crystal layer interposed therebetween with the long axis of the liquid crystal molecules oriented almost perpendicular to these display panels.

First, a thin film transistor array panel will be described in detail with reference to FIGS. 1A to 1C.

FIG. 1A is a layout view of a thin film transistor array panel of a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 1B is a cross-sectional view of the thin film transistor array panel of FIG. 1A taken along line Ib-Ib ′, and FIG. 1C is a cross-sectional view of FIG. A cross-sectional view of the thin film transistor array panel taken along the line Ic-Ic '.

The gate line 22 is formed in the horizontal direction on the insulating substrate 10, and the gate electrode 26 formed in the form of a protrusion is formed on the gate line 22. At the end of the gate line 22, a gate line end 24 for receiving a gate signal from another layer or the outside and transmitting the gate signal to the gate line 22 is formed, and the gate line end 24 is connected to an external circuit. The width is expanded for The gate line 22, the gate electrode 26, and the gate line end 24 are referred to as gate wirings.

In addition, on the insulating substrate 10, a storage electrode line 28 extending in the horizontal direction substantially in parallel with the gate line 22 is formed. The sustain electrodes 29a, 29b, 29c, and 29d branched from the sustain electrode line 28 are formed in the pixel along the edges of the first subpixel electrode 82a and the second subpixel electrode 82b which will be described later. For example, the sustain electrodes may extend along the data lines 62 from the sustain electrode lines 28 and overlap the first and second subpixel electrodes 82a and 82b, and the sustain electrodes vertical patterns 29a and 29b. Storage electrode diagonal patterns 29c and 29d connecting diagonally between storage electrode vertical patterns 29a and 29b along a gap 83 separating the first and second subpixel electrodes 82a and 82b. Include. Such sustain electrode lines 28, sustain electrodes 29a, 29b, 29c, and 29d and sustain electrode extension 27 are referred to as sustain electrode wiring.

In order to increase the aperture ratio of the liquid crystal display, the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d are formed along edges of the first subpixel electrode 82a and the second subpixel electrode 82b. The present invention is not limited thereto, and the storage electrode wirings 27, 28, 29a, and the like may be satisfied within a range in which a constant storage capacitance can be formed with the first subpixel electrode 82a and the second subpixel electrode 82b. The shape and arrangement of 29b, 29c, 29d) can be modified in many forms.

The gate wirings 22, 24, 26 and the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d are aluminum-based metals such as aluminum (Al) and aluminum alloys, and silver-based such as silver (Ag) and silver alloys. Metal, copper (Cu) and copper alloys such as copper-based metals, molybdenum (Mo) and molybdenum alloys such as molybdenum-based metals, such as chromium (Cr), titanium (Ti), tantalum (Ta) and the like. In addition, the gate wirings 22, 24, 26 and the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d may have a multilayer structure including two conductive films (not shown) having different physical properties. have. One of these conductive films is a low resistivity metal such as to reduce signal delay or voltage drop in the gate wirings 22, 24, 26 and sustain electrode wirings 27, 28, 29a, 29b, 29c, 29d, for example. For example, it consists of aluminum type metal, silver type metal, copper type metal, etc. In contrast, the other conductive layer is made of a material having excellent contact properties with other materials, particularly indium tin oxide (ITO) and indium zinc oxide (IZO), such as molybdenum-based metals, chromium, titanium, tantalum and the like. A good example of such a combination is a chromium bottom film and an aluminum top film and an aluminum bottom film and a molybdenum top film. However, the present invention is not limited thereto, and the gate wirings 22, 24, 26 and the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d may be made of various metals and conductors.

The gate insulating film 30 is formed on the gate wirings 22, 24, 26 and the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d.

On the gate insulating film 30, a semiconductor layer 40 made of hydrogenated amorphous silicon, polycrystalline silicon, or the like is formed. The semiconductor layer 40 may have various shapes such as an island shape and a linear shape. For example, the semiconductor layer 40 may be formed in an island shape on the gate electrode 26 as in the present embodiment. In addition, when the semiconductor layer 40 is linearly formed, the semiconductor layer 40 may be positioned below the data line 62 and extend to the upper portion of the gate electrode 26.

Resistive contact layers 55 and 56 made of a material such as n + hydrogenated amorphous silicon doped with silicide or n-type impurities at a high concentration are formed on the semiconductor layer 40. The ohmic contacts 55 and 56 may have various shapes such as islands and linear shapes. For example, in the case of the islands of ohmic contact layers 55 and 56, the drain electrode 66 and the source electrode may have different shapes. Located below 65, the linear ohmic contact layer may extend below the data line 62.

The data line 62 and the drain electrode 66 are formed on the ohmic contacts 55 and 56 and the gate insulating layer 30. The data line 62 extends long and crosses the gate line 22 to define a pixel. The source electrode 65 extending from the data line 62 to the top of the semiconductor layer 40 in the form of a branch is formed. A data line end 68 is formed at the end of the data line 62 to receive a data signal from another layer or the outside and transmit the data signal to the data line 62. The data line end 68 is connected to an external circuit. The width is expanded for The drain electrode 66 is separated from the source electrode 65 and positioned above the semiconductor layer 40 so as to face the source electrode 65 with respect to the gate electrode 26.

The drain electrode 66 includes a rod pattern on the semiconductor layer 40 and a drain electrode extension 67 extending from the rod pattern and having a large area and in which the contact hole 76 is located. A coupling electrode 69 made of the same material on the same layer as the drain electrode 66 is formed branched from the drain electrode 66. The coupling electrode 69 overlaps the second subpixel electrode 82b to form a coupling capacitance. The coupling electrode 69 may be formed along the cutout (see reference numeral 92 of FIG. 3A) of the common electrode to increase the aperture ratio and prevent texture, light leakage, and the like.

The data line 62, the data line end 68, the source electrode 65, the drain electrode 66, and the coupling electrode 69 are referred to as data wirings.

The data wires 62, 65, 66, 67, and 68 are preferably made of refractory metals such as chromium, molybdenum-based metals, tantalum and titanium, and a lower resistive material such as a refractory metal and a low resistance material disposed thereon. It may have a multi-layered film structure consisting of an upper film (not shown). Examples of the multilayer film structure include a triple film of molybdenum film, aluminum film, and molybdenum film in addition to the above-described double film of chromium lower film and aluminum upper film or aluminum lower film and molybdenum upper film.

The source electrode 65 overlaps at least a portion of the semiconductor layer 40, and the drain electrode 66 faces the source electrode 65 around the gate electrode 26 and at least partially overlaps the semiconductor layer 40. do. Here, the ohmic contacts 55 and 56 are interposed between the semiconductor layer 40 and the source electrode 65, and the semiconductor layer 40 and the drain electrode 66 to lower the contact resistance therebetween.

A passivation layer 70 made of an insulating layer is formed on the data line 62, the drain electrode 66, and the exposed semiconductor layer 40. The protective film 70 is an inorganic material made of silicon nitride or silicon oxide, an organic material having excellent planarization characteristics and photosensitivity, or a-Si: C: O formed by plasma enhanced chemical vapor deposition (PECVD). and a low dielectric constant insulating material such as a-Si: O: F. In addition, the passivation layer 70 may have a double layer structure of the lower inorganic layer and the upper organic layer in order to protect the exposed portion of the semiconductor layer 40 while maintaining excellent characteristics of the organic layer.

In the passivation layer 70, contact holes 76 and 78 exposing the drain electrode 66 and the data line end 68 are formed, respectively, and the passivation layer 70 and the gate insulating layer 30 are formed at the gate line end. The contact hole 74 which exposes the 24 is formed.

The pixel electrode 82 is formed on the passivation layer 70 along the shape of the pixel. The pixel electrode 82 is formed of a first subpixel electrode 82a and a second subpixel electrode separated by a predetermined gap 83 that forms about 45 degrees or -45 degrees with the transmission axis 1 of the polarizing plate. (82b). Here, the gap 83 includes a portion that is substantially 45 degrees with the transmission axis 1 of the polarizing plate and a portion that is -45 degrees. The second subpixel electrode 82b has a substantially V-shaped trapezoidal shape and is disposed in the center of the pixel area. The first subpixel electrode 82a is formed at a portion of the pixel region except for the second subpixel electrode 82b. Here, a plurality of cutouts (not shown) or protrusions (not shown) may be formed in the diagonal direction in the first or second subpixel electrodes 82a and 82b. The display area of the pixel electrode 82 is divided into a plurality of domains according to a direction in which the main directors of the liquid crystal molecules included in the liquid crystal layer are arranged when an electric field is applied, and such domain division means such as cutouts or protrusions are arranged in the pixel electrode 82. ) Split into more domains. In this case, the domain refers to an area formed of liquid crystal molecules in which the directors of the liquid crystal molecules are inclined in a specific direction by an electric field formed between the pixel electrode 82 and the common electrode (see 90 in FIG. 2).

The first subpixel electrode 82a is electrically connected to the drain electrode 66 through the contact hole 76, and the second subpixel electrode 82b is not directly connected to the drain electrode 66. It is coupled with the drain electrode 66 by a coupling electrode 69 extending from 66.

In addition, the auxiliary gate line end 86 and the auxiliary data line end 88, which are connected to the gate line end 24 and the data line end 68, respectively, through the contact holes 74 and 78 on the passivation layer 70. Formed. In addition, the protective film 70 is provided with contact holes 77 exposing the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d, which are adjacent to each other via the contact holes 77 on the protective film 70. The connection member 84 which connects the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d arranged in the pixel area is formed. Here, the pixel electrode 82, the auxiliary gate line end 86, the auxiliary data line end 88, and the connecting member 84 are made of a transparent conductor such as ITO or IZO or a reflective conductor such as aluminum. The auxiliary gate line and data line ends 86 and 88 serve to bond the gate line end 24 and the data line end 68 to an external device.

The first subpixel electrode 82a is physically and electrically connected to the drain electrode 66 through the contact hole 76 to receive a data voltage from the drain electrode 66. Although the second subpixel electrode 82b is in an electrically floating state, the second subpixel electrode 82b is capacitively coupled to the first subpixel electrode 82a by overlapping the coupling electrode 69 connected to the drain electrode 66. Doing. That is, the voltage of the second subpixel electrode 82b is changed in accordance with the voltage applied to the first subpixel electrode 82a. At this time, the voltage of the second subpixel electrode 82b is lower than the voltage of the first subpixel electrode 82a. However, the voltage applied to the first subpixel electrode 82a and the second subpixel electrode 82b is not limited thereto, and the data voltage is applied to the second subpixel electrode 82b from the drain electrode 66. The first subpixel electrode 82a may be capacitively coupled to the second subpixel electrode 82b.

As such, when two subpixel electrodes 82a and 82b having different data voltages are disposed in one pixel, the two subpixel electrodes 82a and 82b compensate for each other to reduce the distortion of the gamma curve, thereby widening the reference viewing angle. .

An alignment layer (not shown) may be coated on the pixel electrode 82, the auxiliary gate lines, the data line ends 86 and 88, and the passivation layer 70.

Hereinafter, a common electrode display panel for a liquid crystal display and a liquid crystal display including the same will be described with reference to FIGS. 2 to 3B. 2 is a layout view of a common electrode display panel for a liquid crystal display according to an exemplary embodiment of the present invention. 3A is a layout view of a liquid crystal display including the thin film transistor array panel of FIG. 1A and the common electrode panel of FIG. 2. 3B is a cross-sectional view of the liquid crystal display of FIG. 3A taken along line IIIb-IIIb '.

2 to 3B, a black matrix 94 for preventing light leakage on an insulating substrate 96 made of a transparent insulating material such as glass, and red, green, and blue color filters sequentially arranged in each pixel. A 98 is formed, and a common electrode 90 having a domain dividing means 92 formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the color filter 98. It is. Here, the domain dividing means 92 may use a cutout or a protrusion, and for convenience of description, the present invention will be described using the domain dividing means 92 formed of the cutout.

The common electrode 90 faces the pixel electrode 82 and is separated by a predetermined gap 93 formed between about 45 degrees or about -45 degrees to the transmission axis 1 of the polarizing plate. And a second subcommon electrode 90b. Here, the gap 93 has a portion substantially 45 degrees with the transmission axis 1 of the polarizing plate, a portion substantially parallel with the data line 62, and -45 degrees substantially with the transmission axis 1 of the polarizing plate. It includes the parts that make up. In an exemplary embodiment, as shown in FIG. 3A, the gap 93 of the common electrode 90 may be formed along the gap 83 of the pixel electrode 82. The second sub common electrode 90b has a substantially trapezoidal shape and is disposed to correspond to the second subpixel electrode 82b. The first sub common electrode 90a is disposed to correspond to the first subpixel electrode 82a at a portion of the pixel area except for the second sub common electrode 90b.

Since the common voltages Vcom1 and Vcom2 are electrically applied to the first sub-common electrode 90a and the second sub-common electrode 90b and different from each other, the flicker and the afterimage problem may be suppressed. If the same common voltage is applied to the first and second sub common electrodes 90b, the data voltage of the second subpixel electrode 82b is smaller than the data voltage of the first subpixel electrode 82a. In other words, the electric field value between the second subpixel electrode 82b and the second subcommon electrode 90b is smaller than the electric field value between the first subpixel electrode 82a and the first subcommon electrode 90a. Therefore, since the kickback voltage for the second subpixel electrode 82b is greater than that of the first subpixel electrode 82a, flicker and afterimage may occur. Therefore, by making the common voltage Vcom2 applied to the second sub common electrode 90b lower than the common voltage Vcom1 applied to the first sub common electrode 90a, flicker and residual images can be suppressed as a whole.

The first or second sub-common electrodes 90a and 90b constituting the common electrode 90 have a plurality of domain dividing means 92 inclined at about 45 degrees or -45 degrees with respect to the transmission axis 1 of the polarizing plate. Can be.

The domain dividing means 92 has a notch 91 which has a concave chamfered shape, which may have a triangular or square or trapezoidal or semicircular shape and is arranged at the boundary of the domain. These can be arranged stably and regularly through the notch 91 to prevent spots or afterimages from occurring at domain boundaries.

An anti-corrosion film (not shown) may be coated on the common electrode 90 to align the liquid crystal molecules.

As shown in FIG. 3A, the domain dividing means 92 of the common electrode 90 may be alternately arranged with the gap 83 dividing the pixel electrode 82.

As shown in FIG. 3B, when the thin film transistor array panel 200 and the common electrode panel 100 having such a structure are aligned and coupled to each other, the liquid crystal layer 300 is formed therebetween to form a vertical alignment. The basic structure of the liquid crystal display according to the embodiment is made.

The liquid crystal molecules included in the liquid crystal layer 300 have their directors with respect to the thin film transistor array panel 100 and the common electrode display panel 200 without an electric field applied between the pixel electrode 82 and the common electrode 90. It is oriented perpendicularly and has negative dielectric anisotropy. The thin film transistor array panel 100 and the common electrode display panel 200 are aligned such that the pixel electrode 82 accurately overlaps the color filter 98. In this way, the pixel is divided into a plurality of domains by the domain dividing means 92 of the common electrode 90 and the gap 83 of the pixel electrode 82. At this time, the pixel is divided into left and right by the gap 83, but the vertically divided liquid crystals are divided into domains in the vertical direction because the alignment directions of the liquid crystals are different from each other. That is, the pixel is divided into a plurality of domains according to the direction in which the main directors of the liquid crystal molecules included in the liquid crystal layer are arranged when the electric field is applied.

The liquid crystal display device is formed by disposing elements such as a polarizing plate and a backlight on the basic structure.

At this time, the polarizing plate (not shown) is disposed one each on both sides of the basic structure and the transmission axis 1 is arranged to be parallel to the gate line 22 and the other one is perpendicular to it.

When the liquid crystal display device is formed as described above, when an electric field is applied to the liquid crystal, the liquid crystal in each domain is inclined in a direction perpendicular to the gap 83 or the domain dividing means 92 for dividing the domain. Therefore, the liquid crystal of each domain is inclined at about 45 degrees or -45 degrees with respect to the transmission axis 1 of the polarizing plate. A lateral field formed between the gap 83 or the domain dividing means 92 assists the liquid crystal alignment of each domain.

Meanwhile, in the liquid crystal display having the structure, the first subpixel electrode 82a receives an image signal voltage through the thin film transistor, whereas the second subpixel electrode 82b is capacitively coupled with the drain electrode extension 67. As a result, the voltage of the second subpixel electrode 82b is lower than the voltage of the first subpixel electrode 82a. As such, when two subpixel electrodes 82a and 82b having different voltages are disposed in one pixel, the two subpixel electrodes 82a and 82b compensate for each other to reduce distortion of the gamma curve.

Next, a coupling relationship between the first subpixel electrode 82a and the second subpixel electrode 82b will be described with reference to FIG. 4. 4 is a circuit diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

In FIGS. 3A and 4, Clca represents a liquid crystal capacitance formed between the first subpixel electrode 82a and the first subcommon electrode 90a, and Csta represents the first subpixel electrode 82a and the sustain electrode wiring 27. , 28, 29a, 29b, 29c, and 29d, respectively, and Cstb is formed between the second subpixel electrode 82b and the sustain electrode wirings 27, 28, 29a, 29b, 29c, and 29d. Retention capacity is indicated. Clcb represents the liquid crystal capacitance formed between the second subpixel electrode 82b and the second subcommon electrode 90b, and Ccp represents between the first subpixel electrode 82a and the second subpixel electrode 82b. The coupling capacitance formed by the coupling of the second subpixel electrode 82b and the coupling electrode 69 is shown.

Referring to FIG. 4, the thin film transistor Q of each pixel is a control terminal (or gate electrode 26) connected to the gate line G 22, and an input terminal connected to the data line D 62. (Or source electrode 65) and an output terminal (or drain electrode 66) connected to liquid crystal capacitors Clca, Clcb and sustain capacitor Cst.

If the voltage of the first subpixel electrode 82a with respect to the voltage of the common electrode 90 is Va and the voltage of the second subpixel electrode 82b is Vb, according to the voltage division law,

Vb = Va × [Ccp / (Ccp + Clcb + Cstb)]

Since Ccp / (Ccp + Clcb + Cstb) is smaller than 1, Vb is smaller than Va. And by adjusting Ccp, we can adjust the ratio of Vb to Va. The adjustment of Ccp is possible by adjusting the overlapping area or distance of the second subpixel electrode 82b and the coupling electrode 69. As such, the arrangement of the coupling electrode 69 may be variously modified.

5 is a waveform diagram illustrating an output waveform of a data voltage by a liquid crystal display according to an exemplary embodiment of the present invention. As shown in FIG. 5, the first sub-common electrode and the second sub-common electrode may be electrically separated from each other, and different common voltages Vcom1 and Vcom2 may be applied to suppress flicker and afterimage problems. For example, when the data voltage of the second subpixel electrode is smaller than the data voltage of the first subpixel electrode, a common voltage Vcom2 applied to the second subcommon electrode is applied to the first subcommon electrode. By making it smaller than the common voltage Vcom1, flicker and an afterimage can be suppressed as a whole.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

As described above, according to the liquid crystal display according to the present invention, a liquid crystal display capable of improving flicker and afterimage characteristics may be implemented.

Claims (7)

A first insulating substrate; A gate line formed on the first insulating substrate; A data line insulated from and intersecting the gate line; A pixel electrode including first and second subpixel electrodes to which different voltages are applied; A thin film transistor connected to the gate line and the data line to apply a voltage to the pixel electrode; A second insulating substrate facing the first insulating substrate; And And a common electrode formed on the second insulating substrate, the common electrode including first and second sub common electrodes to which different common voltages are respectively applied to the first and second subpixel electrodes. According to claim 1, The pixel electrode is separated into the first and second subpixel electrodes by a first gap, The common electrode is separated into the first and second sub-common electrodes by a second gap, And the second gap is formed along the first gap. According to claim 1, The common electrode is separated into the first and second sub-common electrodes by a second gap, And the second gap includes a portion substantially 45 degrees to the transmission axis of the polarizer, a portion substantially parallel to the data line, and a portion substantially to -45 degrees to the transmission axis of the polarizer. According to claim 1, The second sub-common electrode has a substantially trapezoidal shape and is disposed in the center of the pixel area. The first sub common electrode is formed in a portion of the pixel region except for the second sub common electrode. According to claim 1, The voltage applied to the second subpixel electrode has a lower absolute value than the voltage applied to the first subpixel electrode. The method of claim 5, The common voltage applied to the second sub common electrode is lower than the common voltage applied to the first sub common electrode. According to claim 1, The liquid crystal display device capacitively couples the first subpixel electrode and the second subpixel electrode.

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