KR100853770B1 - Multi domain Liquid Crystal Display Device - Google Patents

Abstract

The present invention is a first substrate and a second substrate; A gate line and a data line formed vertically and horizontally on the first substrate to define a pixel area; A plurality of pixel electrodes formed in the pixel region; A plurality of thin film transistors connected to each of the plurality of pixel electrodes; A light blocking film formed on the second substrate; A color filter layer formed on the light blocking layer; A common electrode formed on the color filter layer; A dielectric protrusion formed on the common electrode; And a liquid crystal layer formed between the first substrate and the second substrate, wherein the dielectric protrusion is formed on the light blocking film forming region between the pixel electrodes, or an auxiliary electrode formed on a layer different from the pixel electrode on the first substrate. And the dielectric protrusion formed on the light blocking film forming region between the pixel electrodes, wherein the light blocking film is formed to correspond to a region other than the region where the pixel electrode is formed. Regarding,

According to the present invention, it is possible to minimize the foreground generation area while maximizing the multi-domain effect.

Pixel Electrode,

Description

Multi domain Liquid Crystal Display Device

1A and 1B are plan views of unit pixels of a lower substrate and an upper substrate for a conventional VA mode multi-domain liquid crystal display device, respectively.

FIG. 1C illustrates a structure in which an upper substrate and a lower substrate are coupled to each other, and is a cross-sectional view corresponding to line A-A of FIGS. 1A and 1B.

2A and 2B are plan views of a lower substrate and an upper substrate for a multi-domain liquid crystal display device according to a first embodiment of the present invention, respectively.

3A and 3B illustrate a structure in which an upper substrate and a lower substrate are coupled to each other, and are cross-sectional views corresponding to lines B-B and C-C of FIGS. 2A and 2B, respectively.

4A and 4B are plan views illustrating various types of pixel electrodes according to the present invention.

5A to 5C are plan views illustrating various types of dielectric protrusions according to the present invention.

6A and 6B are plan views of a lower substrate and an upper substrate for a multi-domain liquid crystal display device according to a second embodiment of the present invention, respectively.

7A to 7C are cross-sectional views corresponding to C-C lines of FIGS. 6A and 6B as a coupling structure according to various embodiments of the upper substrate and the lower substrate.                 

<Description of main parts of drawing>

12, 120: gate line 14, 140: data line

16, 160: gate insulating film 18, 180: protective film

20, 200: thin film transistor 30, 300: pixel electrode

42, 420, 420a: Light shielding film 48, 480: Dielectric projection

46, 460: common electrode

The present invention relates to a liquid crystal display device, and more particularly, to a multi-domain liquid crystal display device in which the foreground line generating area is minimized.

In general, a liquid crystal display device is composed of a lower substrate and an upper substrate facing each other at a predetermined interval, and a liquid crystal layer formed between the two substrates.

Among the liquid crystal display devices, the vertical alignment mode liquid crystal display device uses a negative liquid crystal having a negative dielectric anisotropy. In a state where no voltage is applied, the long axis direction of the liquid crystal molecules is perpendicular to the alignment layer plane. When the voltage is applied, the liquid crystal molecules are displayed at an angle by controlling the transmittance of light using the property of being oriented obliquely by the electric field.

Meanwhile, in the vertical alignment mode, in order to realize a wide viewing angle, an auxiliary electrode, a dielectric protrusion (Rib), or a slit is formed on a substrate to distort the electric field applied to the liquid crystal layer, thereby desired the director of the liquid crystal molecules. A method for implementing a multi-domain by positioning in a direction has been proposed, which will be described below with reference to the drawings.

1A is a plan view of a unit pixel of a lower substrate for a conventional VA mode multi-domain liquid crystal display device, FIG. 1B is a plan view of a unit pixel of an upper substrate, and FIG. 1C is a structure in which an upper substrate and a lower substrate are combined. And cross-sectional view corresponding to line AA of FIG. 1B.

1A, 1B, and 1C, first, a gate line 12 and a data line 14 are formed on the lower substrate 10 vertically and horizontally to define a pixel region, and the gate line 12 is formed. ) And the gate electrode 22, the gate insulating film 16, the semiconductor layer 24, the ohmic contact layer (not shown), the source electrode 26 and the drain electrode 28, and the protective film at the intersection of the data line 14 and the data line 14. A thin film transistor 20 formed of 18 is formed, and is connected to the drain electrode 28 of the thin film transistor 20 and the pixel electrode 30 is formed in the pixel region.

In addition, a light blocking layer 42 is formed on the upper substrate 40 to block light leaking to areas other than the pixel area, and a color filter layer 44 is formed on the light blocking layer. The common electrode 46 is formed on the 44.

In addition, a dielectric protrusion 48 is formed on the common electrode 46 to realize a multi-domain effect by distorting an electric field.

In the conventional multi-domain liquid crystal display device having such a structure, in order to implement a wide viewing angle, the dielectric protrusions 48 may be formed in various shapes to divide the domains in various ways. Therefore, the range of foreground lines generated in the region where the dielectric protrusions 48 are formed also increases, thereby decreasing the aperture ratio.                         

In addition, when the width of the dielectric protrusion 48 is small, the distortion degree of the electric field required for domain division is weakened, and thus the time for reaching the stable state of the liquid crystal director is relatively long. Therefore, the width of the dielectric protrusion 48 should be increased. This also entails an increase in the foreground generation area.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device capable of realizing a multi-domain effect while minimizing a foreground generation area.

The present invention to achieve the above object, the first substrate and the second substrate; A gate line and a data line formed vertically and horizontally on the first substrate to define a pixel area; A plurality of pixel electrodes formed in the pixel region; A plurality of thin film transistors connected to each of the plurality of pixel electrodes; A light blocking film formed on the second substrate; A color filter layer formed on the light blocking layer; A common electrode formed on the color filter layer; A dielectric protrusion formed on the common electrode; And a liquid crystal layer formed between the first substrate and the second substrate, wherein the dielectric protrusion is formed on the light blocking film forming region between the pixel electrodes, or an auxiliary electrode formed on a layer different from the pixel electrode on the first substrate. And the dielectric protrusion formed on the light blocking film forming region between the pixel electrodes, wherein the light blocking film is formed to correspond to a region other than the region where the pixel electrode is formed. To provide.

That is, the multi-domain liquid crystal display device according to the present invention forms a plurality of pixel electrodes in one pixel region to drive the liquid crystal in various directions, and forms a dielectric protrusion on the common electrode to distort the electric field. The multi-domain effect is realized by dividing the domain by the combination of the pixel electrode and the dielectric protrusion.                     

As described above, the present invention divides the domain by a combination of the plurality of pixel electrodes and the dielectric protrusions, so that the width of the dielectric protrusions can be reduced, and the shape thereof can be simply formed, and the aperture ratio can be increased. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First embodiment

2A is a plan view of a lower substrate for a multi-domain liquid crystal display device according to an exemplary embodiment of the present invention, FIG. 2B is a plan view of an upper substrate, and FIGS. 3A and 3B are structures in which an upper substrate and a lower substrate are combined. Sectional drawing corresponding to the BB line and CC line of FIG. 2A and FIG. 2B.

As shown in FIGS. 2A, 2B, 3A, and 3B, first, a gate line 120 and a data line 140 are formed on the lower substrate 100 to be vertically and horizontally defining a pixel area. .

A plurality of pixel electrodes 300 are formed in the pixel region. In this case, although the structure in which four pixel electrodes are formed is illustrated, two pixel electrodes may be formed as shown in FIGS. 4A and 4B, and more pixel electrodes may be formed in one pixel area. In addition, not only a rectangular structure, but also a pentagonal, hexagonal structure as shown in the figure.

The pixel electrode 300 is preferably made of indium tin oxide (ITO) or indium zinc oxide (IZO).

The gate electrode 220, the gate insulating layer 160, the semiconductor layer 240, the ohmic contact layer, the source electrode 260 and the drain electrode 280 are connected to each of the plurality of pixel electrodes 300. The thin film transistor 200 formed of the passivation layer 180 is formed at the intersection of the gate line 120 and the data line 140.

As described above, the thin film transistor 200 may be easily changed by those skilled in the art according to the number and shape of the pixel electrodes 300.

In this case, the gate insulating layer 16 is formed of SiNx or SiOx, and the protective layer 180 is formed of a material such as BCB (BenzoCycloButene), acrylic resin, polyamide compound, SiNx, or SiOx. do.

A light blocking film 420 is formed on the upper substrate 400, a color filter layer 440 is formed on the light blocking film 420, and a common electrode 460 is formed on the color filter layer 440. A dielectric protrusion 480 is formed on the common electrode 460.

A liquid crystal layer (not shown) is formed between the lower substrate 100 and the upper substrate 400.

In this case, the light blocking film 420 is formed in a region other than the region where the pixel electrode 300 is formed, and serves to block light leakage to the region. In addition, since the foreground line may occur near the edge of the pixel electrode 300 due to the structure of the pixel electrode 300, the light shielding film 420 may be formed to a region corresponding to the edge of the pixel electrode.

In addition, the dielectric protrusion 480 may be formed in various shapes as shown in FIGS. 5A to 5C. The dielectric protrusion 480 may be formed on an area of the light shielding film 420 (see FIG. 2B), or may be formed in a region other than the light shielding film formation region. It may be.

On the other hand, because the foreground line is generated in the region where the dielectric protrusion 480 is formed, it should be prevented from transmitting light to the portion. Therefore, when the dielectric protrusion 480 is formed on the light blocking film 420 forming region, a separate light blocking layer is not required. However, when the dielectric protrusion 480 is formed in a region other than the light blocking film forming region, a separate light blocking layer is required.

It is preferable that the dielectric constant of the dielectric protrusion 480 is equal to or smaller than the dielectric constant of the liquid crystal, preferably 3 or less. In addition, the dielectric protrusion 480 is preferably made of a photosensitive material, more preferably made of acrylic resin (photoacrylate) or BCB (BenzoCycloButene).

In addition, the liquid crystal is a liquid crystal having a negative dielectric anisotropy, and the chiral dopant is preferably included in the VA (Vertical Alignment) liquid crystal so that the molecular arrangement and optical axis of the liquid crystal are continuously formed by applying an electric field.

In addition, the gate line 160, the data line 180, the color filter layer 440, and the common electrode 460 may be easily implemented by those skilled in the art having ordinary skill in the art. It can be formed by changing within.

In addition, although not shown in the drawings, an alignment layer may be formed on the entire surface of at least one of the lower substrate 100 and the upper substrate 400.

The alignment layer may be formed by rubbing orientation treatment using a material such as a polyamide or polyimide compound, polyvinylalcohol (PVA), polyamic acid, or the like, or may be formed without orientation treatment. have.

In addition, the photoreaction may be formed using a photoreactive material such as PVCN (polyvinylcinnamate), PSCN (polysiloxanecinnamate), or CelCN (cellulosecinnamate) -based compound, or may be formed without orientation treatment. The light alignment treatment simultaneously determines the pretilt angle, the alignment direction, or the pretilt direction by at least one light irradiation, wherein the light irradiation uses light in the ultraviolet region. Although it is preferable to use, any of unpolarized light, unpolarized light, linearly polarized light, and partially polarized light may be used.

In addition, a retardation film may be formed on an outer surface of at least one of the lower substrate 100 and the upper substrate 400. The retardation film compensates for the viewing angle in the direction perpendicular to the substrate and the direction of the viewing angle change, thereby widening the region without gray inversion, and increasing the contrast ratio in the oblique direction. Although it may be formed as a negative uniaxial film or a negative biaxial film having two optical axes, a negative biaxial film is more preferable in terms of wide viewing angle.

In addition, a polarizer (not shown) may be attached to the lower substrate and the upper substrate 100 and 400, and the polarizer may be integrally formed with the retardation film.

Second embodiment

6A is a plan view of a lower substrate for a multi-domain liquid crystal display device according to another exemplary embodiment of the present invention, FIG. 6B is a plan view of an upper substrate, and FIGS. 7A to 7C are diagrams illustrating various embodiments of an upper substrate and a lower substrate. As a coupling structure, it is sectional drawing corresponding to the CC line of FIG. 6A and 6B.

The second embodiment of the present invention relates to a multi-domain liquid crystal display device in which a dielectric protrusion is formed in a region other than the light shielding film formation region, and is the same as the first embodiment described above except for that. Therefore, the same reference numerals are given, and description of the same parts will be omitted.

As illustrated in FIG. 6B, the dielectric protrusion 480 may be formed in a X shape, and may be formed in a region corresponding to the pixel region in which the pixel electrode 300 is formed in various other forms.

In this case, as described above, when the dielectric protrusion 480 is formed in a region other than the region in which the light shielding film 420 is formed, the foreground line is generated in the region, and thus, a separate light shielding means is required.

Therefore, as shown in FIG. 7A, when forming the light blocking film 420 of the upper substrate 400, a separate light blocking film 420a may be formed to correspond to the dielectric protrusion 480. As shown in FIGS. 7B and 7C, the lower substrate may be formed. It is also possible to form the auxiliary electrode 500 on the (100).

In this case, as shown in FIG. 7B, the auxiliary electrode 500 may be formed on the same layer as the gate line 120 or on the same layer as the data line 140.

The auxiliary electrode 500 is electrically connected to the common electrode 460 on the upper substrate 400, and serves to enhance the field distortion as well as light shielding, indium tin oxide (ITO), Al, and Mo. It is preferably made of any one material selected from the group consisting of Cr, Ta, Ti, and Al alloys.

The multi-domain liquid crystal display device according to the present invention having the above configuration can maximize the multi-domain effect while minimizing the foreground line generating area.

Claims (12)

A first substrate and a second substrate; A gate line and a data line formed vertically and horizontally on the first substrate to define a pixel area; A plurality of pixel electrodes formed in the pixel region; A plurality of thin film transistors connected to each of the plurality of pixel electrodes; A light blocking film formed on the second substrate; A color filter layer formed on the light blocking layer; A common electrode formed on the color filter layer; A dielectric protrusion formed on the common electrode; And A liquid crystal layer formed between the first substrate and the second substrate, The dielectric protrusion is formed on the light blocking film forming region between the pixel electrodes or overlaps the auxiliary electrode formed on a layer different from the pixel electrode on the first substrate. When the dielectric protrusions are formed on the light shielding film formation region between the pixel electrodes, The light shielding film is formed so as to correspond to a region other than the region where the pixel electrode is formed. delete delete delete delete The method of claim 1, And the auxiliary electrode is formed on the same layer as the gate line. The method of claim 1, And the auxiliary electrode is formed on the same layer as the data line. The method of claim 1, The auxiliary electrode is made of any one material selected from the group consisting of indium tin oxide (ITO), Al, Mo, Cr, Ta, Ti, and Al alloy. The method of claim 1, The liquid crystal is a multi-domain liquid crystal display device characterized in that the chiral dopant is included in the vertical alignment liquid crystal (VA). The method of claim 1, An alignment film is formed on at least one of the first substrate and the second substrate. The method of claim 10, The alignment film is a multi-domain liquid crystal display device, characterized in that the alignment treatment. The method of claim 10, And the alignment layer is not aligned.

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