KR101994970B1

KR101994970B1 - Liquid crystal display

Info

Publication number: KR101994970B1
Application number: KR1020120013020A
Authority: KR
Inventors: 김성훈; 최정수
Original assignee: 삼성디스플레이 주식회사
Priority date: 2012-02-08
Filing date: 2012-02-08
Publication date: 2019-10-01
Also published as: KR20130091609A

Abstract

Provided is a liquid crystal display device. The liquid crystal display according to the exemplary embodiment of the present invention includes a first substrate, a thin film transistor positioned on the first substrate, and a first electrode positioned on the thin film transistor and connected to an output electrode of the thin film transistor. The first electrode includes a first region including a plurality of fine branch portions spaced apart from each other with a first open portion interposed therebetween, and a portion of the at least two fine branch portions of the plurality of fine branch portions are connected to each other to provide a fine branch portion. A second area forming a plurality of thick fine plate branch portions, wherein the plurality of fine plate branch portions are spaced apart from each other with a second open portion interposed therebetween, and the second open portion is wider than the first open portion. Is wide.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY}

The present invention relates to a liquid crystal display device.

The liquid crystal display is one of the most widely used flat panel displays, and includes two display panels on which an electric field generating electrode such as a pixel electrode and a common electrode are formed, and a liquid crystal layer interposed therebetween.

An electric field is generated by applying a voltage to the field generating electrode, thereby determining an orientation of the liquid crystal molecules of the liquid crystal layer and controlling the polarization of incident light to display an image.

The liquid crystal display also includes a switching element connected to each pixel electrode and a plurality of signal lines such as a gate line and a data line for controlling the switching element and applying a voltage to the pixel electrode.

Among such liquid crystal displays, a vertically aligned liquid crystal display in which the long axis of the liquid crystal molecules is arranged perpendicular to the display panel without an electric field applied to the liquid crystal display device has a high contrast ratio and a wide reference viewing angle. .

Among the vertical alignment methods, the liquid crystal display of the super vertical alignment (SVA) mode may increase transmittance by controlling the liquid crystal direction through vertical and horizontal electric fields using an electrode pattern having a fine slit structure.

However, in the SVA mode liquid crystal display, there is a problem that spots occur while the interval between the fine slits or the minute branches is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device that improves transmittance and luminance deterioration while securing a margin for unevenness.

The liquid crystal display according to the exemplary embodiment of the present invention includes a first substrate, a thin film transistor positioned on the first substrate, and a first electrode positioned on the thin film transistor and connected to an output electrode of the thin film transistor. The first electrode includes a first region including a plurality of fine branch portions spaced apart from each other with a first open portion interposed therebetween, and a portion of the at least two fine branch portions of the plurality of fine branch portions are connected to each other to provide a fine branch portion. A second area forming a plurality of thick fine plate branch portions, wherein the plurality of fine plate branch portions are spaced apart from each other with a second open portion interposed therebetween, and the second open portion is wider than the first open portion. Is wide.

The first opening portion extends toward one of the fine plate branch portions of the plurality of fine plate branch portions between two fine branch portions adjacent to each other among the plurality of fine branch portions to form a depression, and the one fine plate branch A portion may be formed by connecting a portion of the two minute branches to each other.

The depression may be triangular in shape.

The depression may be trapezoidal in shape.

The width of the second opening may be greater than the width of the first opening by 10% to 25% of the width of the first opening.

The portion extending from the first open portion to the second open portion may have a shape that gradually widens.

The first electrode may include a cross stem portion including a horizontal stem portion and a vertical stem portion crossing the cross stem portion, and the plurality of fine plate branch portions may extend from the cross stem portion.

The second region in which the plurality of minute plate branch portions are positioned may be vertically or horizontally symmetrical based on the cross stem portion.

The first electrode may include a plurality of regions having the plurality of minute plate branches or the minute branches extending in different directions from the cross stem.

The second region in which the plurality of minute plate branches are positioned may have a square shape.

The minute branch portion may extend from an end of the minute plate branch portion extending from the cross-shaped stem portion, and the first region in which the plurality of minute branch portions is located may be positioned at an edge portion of the first electrode.

The minute plate branch may form an angle of 45 degrees with the horizontal stem portion or the vertical stem portion.

The horizontal stem portion and the vertical stem portion may have different widths.

The first electrode may include a cross stem portion including a horizontal stem portion and a vertical stem portion crossing the cross stem portion, and the plurality of minute branches may extend from the cross stem portion.

The first electrode may include a plurality of regions in which the fine branch portions or the plurality of fine plate branch portions extend in different directions from the cross stem portion.

The minute plate branch may extend from an end of the minute branch extending from the cross stem, and the second region in which the plurality of minute plate branches are located may be positioned at an edge portion of the first electrode.

The direction in which the fine branch portion and the fine plate branch portion extend may be parallel to each other.

The display device may further include a second substrate facing the first substrate and a second electrode positioned on the second substrate, wherein the second electrode may have a plate shape.

As described above, according to the exemplary embodiment of the present invention, the fine branch part is partially bundled to form the fine plate branch part, thereby increasing the width of the fine branch part to secure the spot margin while improving the transmittance. In addition, the gap between the open portions between the minute plate branches may be wider than the gap between the open portions between the minute branch portions, thereby improving luminance.

1 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. 1.
3 is a plan view illustrating a pattern of one subpixel electrode in the embodiment of FIG. 1.
4 is a graph showing luminance according to position in the embodiment of FIG. 1.
FIG. 5 is an enlarged view illustrating the minute plate branch in the embodiment of FIG. 1. FIG.
6 is a plan view illustrating a liquid crystal display according to another exemplary embodiment of the present invention.
FIG. 7 is a plan view illustrating a pattern of one subpixel electrode in the embodiment of FIG. 6.
FIG. 8 is an enlarged view illustrating the minute plate branch in the embodiment of FIG. 6.
Figure 9 is an enlarged view showing a fine plate branch according to another embodiment of the present invention.
10 is an enlarged view illustrating a branch plate part according to still another embodiment of the present invention.
FIG. 11 is a graph illustrating luminance according to position in the embodiment of FIG. 6.
12 is a plan view illustrating a pattern of one subpixel electrode according to another exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art.

In the drawings, the thicknesses of layers and regions are exaggerated for clarity. In addition, where a layer is said to be "on" another layer or substrate, it may be formed directly on the other layer or substrate, or a third layer may be interposed therebetween. Portions denoted by like reference numerals denote like elements throughout the specification.

1 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. 1. 3 is a plan view illustrating a pattern of one subpixel electrode in the embodiment of FIG. 1.

First, referring to FIGS. 1 and 2, a liquid crystal display according to an exemplary embodiment of the present invention includes a lower panel 100 and an upper panel 200 facing each other and between the two display panels 100 and 200. The liquid crystal layer 3 is included.

First, the lower panel 100 will be described.

A plurality of gate lines 121 and a plurality of storage electrode lines 131 and 135 are formed on the insulating substrate 110.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes a plurality of first and second gate electrodes 124a and 124b protruding upward.

The storage electrode line includes a stem line 131 extending substantially in parallel with the gate line 121 and a plurality of storage electrodes 135 extending therefrom. The storage electrode lines 131 and 135 may serve as shielding electrodes in a structure using an organic layer under the pixel electrode 191.

The shape and arrangement of the storage electrode lines 131 and 135 may be modified in various forms.

A gate insulating layer 140 is formed on the gate line 121 and the storage electrode lines 131 and 135, and a plurality of semiconductors 154a and 154b made of amorphous silicon, crystalline silicon, an oxide semiconductor, or the like are formed on the gate insulating layer 140. Formed.

A plurality of pairs of ohmic contacts 163a, 163b, 165a, and 165b may be formed on the semiconductors 154a and 154b, respectively, and may be omitted when the semiconductors 154a and 154b are formed of oxide semiconductors. Such an ohmic contact may be made of a material such as silicide or n + hydrogenated amorphous silicon doped with a high concentration of n-type impurities.

A plurality of pairs of first and second source electrodes connected to the plurality of pairs of data lines 171a and 171b and the data lines 171a and 171b on the ohmic contacts 163a, 163b, 165a and 165b and the gate insulating layer 140. A plurality of pairs of first and second drain electrodes 175a and 175b facing the 173a and 173b and the source electrodes 173a and 173b are formed.

The data lines 171a and 171b transmit data signals and mainly extend in a vertical direction to intersect the gate lines 121 and the stem lines 131 of the storage electrode lines. The first and second source electrodes 173a and 173b extend toward the first and second gate electrodes 124a and 124b to be bent in a U shape, and the first and second source electrodes 173a and 173b are formed in a first shape. The first and second drain electrodes 175a and 175b face the first and second gate electrodes 124a and 124b.

The first and second drain electrodes 175a and 175b extend upward from one end, partially enclosed by the first and second source electrodes 173a and 173b, respectively, with the other end extending wider for connection with the other layer. It may include wealth.

However, the first and second source electrodes 173a and 173b are bent in a U-shape or U-shape, thus forming the shape of the data lines 171a and 171b including the first and second drain electrodes 175a and 175b. And the arrangement or deformation of the data lines 171a and 171b including the first and second source electrodes 173a and 173b and the first and second drain electrodes 175a and 175b in various forms. It can be modified.

The first and second gate electrodes 124a and 124b, the first and second source electrodes 173a and 173b, and the first and second drain electrodes 175a and 175b are formed of the first and second semiconductors 154a and 154b. The first and second thin film transistors TFTs Qa and Qb are formed together, and the channels of the first and second thin film transistors Qa and Qb are formed of the first and second source electrodes. It is formed in the first and second semiconductors 154a and 154b between 173a and 173b and the first and second drain electrodes 175a and 175b.

The semiconductors 154a and 154b have portions exposed between the source electrodes 173a and 173b and the drain electrodes 175a and 175b and not covered by the data lines 171a and 171b and the drain electrodes 175a and 175b.

A lower passivation layer 180a made of silicon nitride or silicon oxide is formed on the data lines 171a and 171b, the source electrodes 173a and 173b, the drain electrodes 175a and 175b, and the exposed semiconductors 154a and 154b. have. The lower passivation layer 180a may be formed of a double layer made of silicon nitride and silicon oxide, as well as a single layer made of silicon nitride or silicon oxide.

The color filter 230 may be positioned on the lower passivation layer 180a. The color filter 230 is positioned in most regions except where the first thin film transistor Qa, the second thin film transistor Qb, and the like are positioned. However, it may extend in the vertical direction along the neighboring data lines 171a and 171b. In the present exemplary embodiment, the color filter 230 is formed on the lower panel 100, but may also be formed on the upper panel 200.

An upper passivation layer 180b is formed on the color filter 230.

The upper passivation layer 180b may be formed of an organic material or an inorganic material having photosensitivity. When the upper passivation layer 180b is formed of an organic material, the upper passivation layer 180b serves to planarize a layer formed at the bottom of the upper passivation layer 180b, and when the upper passivation layer 180b is formed of an inorganic material. The 180b may serve to improve the transmittance through the refractive index compensation or shield the gas eluted from the color filter 230.

In addition to the lower passivation layer 180a, the upper passivation layer 180b includes a plurality of contact holes 185a and 185b exposing the first and second drain electrodes 175a and 175b.

A plurality of pixel electrodes 191 is formed on the upper passivation layer 180b. The pixel electrode 191 may be made of a transparent conductive material such as ITO or IZO, or a reflective metal such as aluminum, silver, chromium, or an alloy thereof.

Each pixel electrode 191 includes first and second subpixel electrodes 191a and 191b separated from each other with the gate line 121 interposed therebetween, and the first subpixel electrode 191a is illustrated in FIG. 3. One electrode pattern is included.

Referring to FIG. 3, the first subpixel electrode 191a will be described in detail.

Referring to FIG. 3, the overall shape of the first subpixel electrode 191a has a quadrangular shape, and includes a cross stem portion including a vertical stem portion 192a and a horizontal stem portion 193a intersecting with the vertical stem portion 192a. In addition, the first subpixel electrode 191a includes the first subregion Da, the second subregion Db, the third subregion Dc by the horizontal stem portion 193a and the vertical stem portion 192a. Each of the subregions Da, Db, Dc, and Dd is divided into a fourth subregion Dd and includes a plurality of minute branch portions 194a and a plurality of minute plate branch portions 195 extending in an oblique direction, respectively. do.

The horizontal stem portion 193a and the vertical stem portion 192a may have the same or different widths. When the width of the horizontal stem portion 193a and the vertical stem portion 192a is the same, the width may be approximately 4um to 7um, and when the widths of the horizontal stem portion 193a and the vertical stem portion 192a are different from each other. The width of the horizontal stem portion 193a may be about 7 μm, and the width of the vertical stem portion 192a may be about 5 μm. Here, the left and right visibility can be further improved by varying the widths of the horizontal stem portion 193a and the vertical stem portion 192a.

The plurality of fine plate branch portions 195 extend obliquely in the upper left direction from the horizontal stem portion 193a or the vertical stem portion 192a in the first subregion Da and the horizontal portion in the second subregion Db. It extends obliquely in the upper right direction from the stem portion 193a or the vertical stem portion 192a. In addition, the plurality of fine plate branch portions 195 extend in the lower left direction from the horizontal stem portion 193a or the vertical stem portion 192a in the third subregion Dc, and the horizontal lines in the fourth subregion Dd. It extends obliquely in the lower right direction from the base 193a or the vertical stem 192a.

A plurality of fine branch portions 194a are connected to the ends of the fine plate branch portions 195 extending from the horizontal stem portion 193a or the vertical stem portion 192a, and two to one fine plate branch portion 195. Four minute branches 194a are connected. The fine plate branch 195 and the minute branch 194a extend in parallel with each other. However, unlike the present exemplary embodiment, the pattern of the first subpixel electrode 191a may be modified in a form in which three or more minute branches 194a are connected to the minute plate branch 195.

A plurality of minute branches 194a is formed with a plurality of open parts OP therebetween to form a first region, and the minute plate branch 195 has an open part OP formed between the minute branches 194a. A plurality is formed with the extended portion therebetween to form the second region.

The fine plate branch 195 will be described in more detail.

A portion of the open part OP positioned between the minute branches 194aa and 194ab adjacent to each other is filled with an electrode material to form the minute plate branch 195. In other words, the branch portions having a wider width are formed by enclosing the adjacent minute branch portions 194aa and 194ab at a portion thereof. Specifically, when the width of the fine branch portions 194aa and 194ab is 2.2 um and the width of the open portion OP is 2.2 um, the width of the fine plate branch portion 195 is 6.6 um. In this embodiment, the electrode pitch may be 4.4 um or 5 um or 6 um. Here, the electrode pitch is a sum of the width of one minute branch 194a and the width of the minute branch 194a and the adjacent open part OP. The width of the minute branch 194a forming the electrode pitch and the width of the open part OP may be the same.

The width of the horizontal stem portion 193a or the width of the vertical stem portion 192a is larger than the fine branch portions 194a, and preferably, at least equal to or greater than the electrode pitch. Because, when the width of the cross-shaped stem portion is smaller than the electrode pitch, the liquid crystal control force may be reduced at the boundary between neighboring domains.

A portion A of the open portion positioned between the minute branches 194aa and 194ab adjacent to each other corresponds to a portion extending from the horizontal stem portion 193a or the vertical stem portion 192a. The minute plate branch 195 formed by filling with the electrode material extends from the horizontal stem portion 193a or the vertical stem portion 192a. In this case, an angle β formed at a portion where all of the minute branches 194aa and 194ab, the minute plate branch 195, and the open part OP meet each other may be approximately 90 degrees.

The overall shape of the second region in which the plurality of fine plate branch portions 195 are positioned may be rhombus, and may be vertically or horizontally symmetric with respect to the cross stem. Alternatively, the overall shape of the second region in which the fine plate branch 195 is located may be square. At this time, when the total area occupied by the first subpixel electrode 191a is 100%, the fine plate branch 195 except for the open part OP in the second region occupied by the fine plate branch 195 is included. ) Area may be approximately 10% to 30%. As a result of the simulation, as the area of the fine plate branch 195 of the second region increases from 10% to 30%, the transmittance decreases and the stain margin increases. It is preferable that the area of the fine plate branch part 195 of the 2nd area | region is about 20% from a viewpoint of transmittance and a stain margin.

The minute branch 194a and the minute plate branch 195 form an angle of approximately 45 degrees or 135 degrees with the gate line 121 or the horizontal stem portion 193a. The fine branch portion 194a and the fine plate branch portion 195 may be formed to form an angle of approximately 45 degrees or 135 degrees with the gate line 121 or the horizontal stem portion 193a to maximize the transmittance. However, the side visibility may be better when forming an angle of about 40 degrees out of 45 degrees, but securing side visibility may be compensated by applying the present embodiment to the 1G2D structure. The 1G2D structure is a structure in which side visibility is secured by varying an electric field formed on two subpixel electrodes by applying a gate voltage through one gate line and applying different data voltages through two data lines. In other words, two pixel transistors are used to drive one pixel area.

In addition, the direction in which the minute branches 194a of the two neighboring subregions Da, Db, Dc, and Dd extend or the direction in which the minute plate branches 195 extend may be perpendicular to each other.

One end of the minute branch 194a is connected by the edge pattern 450 at the left and right edge portions of the first subpixel electrode 191a. In the edge pattern 450, the liquid crystal control of the end of the minute branch 194a is unstable due to a field generated in the data lines 171a and 171b adjacent to the end of the minute branch 194a. Serves to prevent this from happening. The edge pattern 450 is positioned substantially parallel to the data lines 171a and 171b. However, the arrangement of the edge pattern 450 is not limited, and one side of the minute branches 194a may be disposed at the upper and lower edge portions of the first subpixel electrode 191a as well as the left and right edge portions of the first subpixel electrode 191a. It is also possible to form a border pattern (not shown) connected to the ends. Alternatively, a border pattern (not shown) may be formed in which two end portions of the minute branches 194a are connected to two or three edge portions adjacent to each other. The border pattern can be omitted.

The lower protrusion 197a extending from the lower end of the vertical stem portion 192a overlaps the extension of the first drain electrode 175a. Therefore, the vertical stem portion 192a and the first drain electrode 175a are connected through the first contact hole 185a, and the voltage transmitted through the first drain electrode 175a is eventually transferred to the first subpixel electrode 191a. ) May be applied.

Although the first subpixel electrode 191a according to the present exemplary embodiment has been described with reference to the fine branch portion 194a or the fine plate branch portion 195, the following description may be made based on the open portion OP. .

The open part OP includes a first area including a plurality of first open parts connected to the cross stem part and a plurality of second open parts spaced apart from the cross stem part and positioned at an edge of the first subpixel electrode 191a. It includes a second region. The first area including the plurality of first openings corresponds to the second area in which the plurality of minute plate branch parts 195 described above are located, and the second area including the plurality of second open parts is the minute branch 194a. Corresponds to the first region in which. At this time, the spacing between the first openings is greater than the spacing between the second openings.

In addition, the directions in which the first open portion and the second open portion extend are parallel to each other.

Hereinafter, the second subpixel electrode 191b will be described.

Referring back to FIG. 1, the overall shape of the second subpixel electrode 191b is a quadrangular shape, and the vertical stem 192b and the horizontal stem portion 193b intersecting with each other are similar to the first subpixel electrode 191a. It includes a cross stem made of. In addition, similar to the first subpixel electrode 191a, the second subpixel electrode 191b is divided into four subregions by the horizontal stem portion 193b and the vertical stem portion 192b, and each subregion is diagonally formed. It includes a plurality of minute branches 194b extending in the direction.

However, the area occupied by the second subpixel electrode 191b in the entire pixel electrode 191 may be larger than the area occupied by the first subpixel electrode 191a, and in this case, the area of the second subpixel electrode 191b is It may be formed so as to be 1.0 to 2.2 times the area of one subpixel electrode 191a.

In addition, unlike the first subpixel electrode 191a, the second subpixel electrode 191b does not include the minute plate branch 195, and the plurality of minute branches 194b excludes the cross stem. It occupies most of the pixel electrode 191b.

Unlike the case of the first subpixel electrode 191a, one end of the minute branch 194b is not connected to the left and right edge portions of the second subpixel electrode 191b. In other words, the edge pattern 450 positioned at the left and right edges of the first subpixel electrode 191a is not formed on the second subpixel electrode 191b. Instead, one end of the minute branch 194b overlaps the data lines 171a and 171b at the left and right edge portions of the second subpixel electrode 191b.

The horizontal stem 193b and the vertical stem 192b of the second subpixel electrode 191b may have the same width or different widths. When the width of the horizontal stem portion 193b and the vertical stem portion 192b is the same, the width may be approximately 4um to 7um, and when the widths of the horizontal stem portion 193b and the vertical stem portion 192b are different from each other. The width of the horizontal stem portion 193b may be about 7 μm, and the width of the vertical stem portion 192b may be about 5 μm. Here, the left and right visibility can be further improved by varying the widths of the horizontal stem portion 193a and the vertical stem portion 192a.

The minute branches 194b form an angle of approximately 45 degrees or 135 degrees with the gate line 121 or the horizontal stem portion 193b. The fine branch portion 194b may be formed to form an angle of approximately 45 degrees or 135 degrees with the gate line 121 or the horizontal stem portion 193b to maximize transmittance.

In addition, the directions in which the minute branches 194b of two neighboring subregions extend may be perpendicular to each other.

An upper protrusion 197b formed to extend from an upper end of the vertical stem 192b of the second subpixel electrode 191b overlaps the extension of the second drain electrode 175b. Accordingly, the vertical stem portion 192b and the second drain electrode 175b are connected through the second contact hole 185b, and the voltage transferred through the second drain electrode 175b is eventually transferred to the second subpixel electrode 191b. ) May be applied.

In the foregoing, the second subpixel electrode 191b does not include the minute plate branch 195, and the plurality of minute branches 194b occupy most of the second subpixel electrode 191b except for the cross stem. As described. However, in another embodiment, the pattern of the second subpixel electrode 191b may be formed similarly to the pattern of the first subpixel electrode 191a of FIG. 1. In other words, according to the present exemplary embodiment, the second subpixel electrode 191b may be formed to include a minute plate branch like the first subpixel electrode 191a described with reference to FIG. 1. The description of the first subpixel electrode 191a in FIG. 1 may be applied to the second subpixel electrode 191b in the present embodiment. However, since the area occupied by the second subpixel electrode 191b is larger than the area occupied by the first subpixel electrode 191a, when the minute mail branch is formed to 20% of the total subpixel electrode area, the minute mail branch is formed in all pixels. The area occupied by the area of wealth may be too large. Therefore, when the second subpixel electrode 191b is formed in a form including the minute plate branch, the portion of the minute plate branch in the total subpixel electrode area may be smaller than 20%.

As described above, one end of the minute branch 194b is not connected to the left and right edge portions of the second subpixel electrode 191b. However, in another embodiment, one edge of the minute branch 194b is formed at the left and right edge portions of the second subpixel electrode 191b by forming an edge pattern similar to the edge portion of the first subpixel electrode 191a of FIG. 1. Can be connected.

Next, the upper panel 200 will be described.

In the upper panel 200, a light blocking member 220 is formed on the upper substrate 210 corresponding to the second substrate and having a transparent and insulating property.

The light blocking member 220 is called a black matrix and blocks light leakage between the pixel electrodes 191. The light blocking member 220 may include a portion corresponding to the gate line 121 and the data lines 171a and 171b and a portion corresponding to the thin film transistor.

The light blocking member 220 may be formed on the lower substrate 110 instead of the upper substrate 210. In this case, the light blocking member 220 may be mainly located between the neighboring color filters 230.

An overcoat 250 is formed on the light blocking member 220. The overcoat 250 may be made of an insulating material and provide a flat surface. The overcoat 250 may be omitted.

The common electrode 270 is formed on the overcoat 250. Here, the common electrode 270 may be formed in a plate shape in the pixel area. Plate shape refers to the shape of the plate as it is not split.

Alignment layers 11 and 21 are coated on inner surfaces of the lower panel 100 and the upper panel 200, respectively, and they may be vertical alignment layers.

Polarizers (not shown) may be provided on outer surfaces of the lower panel 100 and the upper panel 200.

The liquid crystal layer 3 is interposed between the lower panel 100 and the upper panel 200. The liquid crystal layer 3 includes an alignment polymer formed by irradiating the plurality of liquid crystals 310 and the alignment aid 50. In another embodiment, the alignment polymer may not be included in the liquid crystal layer 3, and the alignment polymer may be included in the alignment layers 11 and 21.

The liquid crystal 310 has negative dielectric anisotropy and is oriented such that its long axis is substantially perpendicular to the surfaces of the two display panels 100 and 200 in the absence of an electric field.

When voltage is applied to the pixel electrode 191 and the common electrode 270, the liquid crystal 310 responds to an electric field formed between the pixel electrode 191 and the common electrode 270, and a long axis thereof is perpendicular to the direction of the electric field. Change direction. The degree of change in polarization of incident light in the liquid crystal layer 3 varies according to the degree of tilt of the liquid crystal 310, and the change in polarization is represented by a change in transmittance by the polarizer, through which the liquid crystal display displays an image.

The direction in which the liquid crystal 310 is inclined is determined by the minute branches 194a of the pixel electrode 191, and the liquid crystal 310 is inclined in a direction parallel to the length direction of the minute branches 194a. Since one pixel electrode 191 includes four subregions Da, Db, Dc, and Dd having different length directions of the minute branches 194a, the direction in which the liquid crystal 310 is inclined is approximately four directions, Four domains having different alignment directions of the liquid crystal 310 are formed in the layer 3. As described above, the viewing angle of the liquid crystal display may be improved by varying the direction in which the liquid crystal is inclined.

The alignment polymer formed by the polymerization of the alignment aid 50 serves to control pre-tilt, which is the initial alignment direction of the liquid crystal 310. The orientation aid 50 may be a conventional reactive mesogen.

The alignment aider 50 has a shape similar to that of the liquid crystal and has a core group forming a central axis and a terminal group connected thereto, similarly to the liquid crystal.

Unlike the present embodiment, the alignment aid 50 may be included in the alignment layers 11 and 21.

4 is a graph showing luminance according to position in the embodiment of FIG. 1. Specifically, the luminance according to the position is represented by the first luminance in the X-Y line of FIG. 3, and the luminance according to the position is represented as the second luminance in the X′-Y ′ line of FIG. 3. FIG. 5 is an enlarged view illustrating the minute plate branch in the embodiment of FIG. 1. FIG.

Referring to FIG. 4, the luminance change in the open part OP between the plurality of minute branches 194a and the adjacent minute branches 194aa and 194ab is represented as the first brightness. The first luminance represents the maximum luminance in the fine branch portion 194a and the lowest luminance at the S point corresponding to the open portion OP. Similarly, a change in luminance at the open portion OP ′ between the plurality of fine plate branch portions 195 and the adjacent fine plate branch portions 195 is represented as the second luminance, and the second luminance is the fine plate branch portion ( In FIG. 195, the maximum brightness is shown, and the lowest brightness is displayed at the point S ′ corresponding to the open part OP ′.

However, when looking at the second luminance in more detail, referring to FIG. 5, the luminance is rather decreased at the center of the fine plate branch 195, and the maximum luminance is increased at the right side or the left side of the fine plate branch 195. You can see it appear. Here, the right part or the left part generally indicates an area located between the center portion and the edge portion of the fine plate branch 195. Referring to FIG. 3, two minute branches 194aa and 194ab are connected at a portion to form a fine plate branch 195, and one of the openings OP between the minute branches 194a is a minute plate branch. Since the other one of the open portions OP between the minute branches 194a corresponds to the central portion of the portion 195 is connected to the open portion OP ′ between the minute mail branch portions 195, the same graph as described above. Interpretation is possible.

The cause of such a phenomenon will be described with reference to FIG. 5.

Referring to FIG. 5, the liquid crystals 310 are arranged according to positions when viewed in a plan view, and the closer the shape of the liquid crystals 310 is to the circle, the closer to the vertical shape, the longer the long axis of the ellipse shape is. Numeral 310 indicates a state of laying down.

In the case where the liquid crystal 310 is arranged in parallel with the direction in which the fine plate branch 195 or the minute branches 194aa and 194ab extend, the liquid crystal 310 exhibiting the maximum luminance in FIG. 5. The lines connecting the arrays of are represented by the luminance peak line BPL.

The luminance peak line BPL extends across the center portion of the fine branch portion 194a and when it meets the fine sheet branch portion 195, is slightly inclined toward the center portion of the fine sheet branch portion 195, and then returns to the initial direction. Stretches along

In the minute branches 194a, the fringe fields act on both sides, and the strongest fringe field is applied at the center portion of the minute branches 194a. Therefore, the luminance peak line BPL extends across the central portion of the fine branch portion 194a. However, in the fine mail branch 195, since the open part originally located in the center of the fine mail branch 195 is filled with the electrode material, the fringe field applied at the right side of the fine mail branch 195 is a fine mail branch. It is stronger than the fringe field on the left side of (195). Accordingly, the luminance peak line BPL is inclined from the line crossing the center portion of the fine base portion 194a and then goes back to the line crossing the center portion of the fine branch portion 194a from the inside of the fine mail branch 195. Stretch side by side

In addition, the liquid crystals 310 in the central portion of the fine plate branch 195 have a relatively weak distance from the open portion OP ′ relative to the fine branch portion 194a, so that the force of the fringe field is relatively weak. Falls. Thus, the luminance tends to fall relative to the surroundings.

1 to 3 have the advantage of securing the spot margin by increasing the width of the minute branch while improving the transmittance by partially forming the fine branch part by tying the minute branch part partially, but partially lowering the luminance There is this. A complementary embodiment will be described below to improve this luminance reduction tendency.

6 is a plan view illustrating a liquid crystal display according to another exemplary embodiment of the present invention. FIG. 7 is a plan view illustrating a pattern of one subpixel electrode in the embodiment of FIG. 6. FIG. 8 is an enlarged view illustrating the minute plate branch in the embodiment of FIG. 6.

6 to 8, most components are the same as the embodiment described with reference to FIGS. Therefore, the contents described with reference to FIGS. 1 to 3 may be applicable to the exemplary embodiments of FIGS. 6 to 8, and the differences will be described below.

6 to 8, unlike the embodiment described with reference to FIGS. 1 to 3, the width of the first opening part OP positioned between the minute branches 194a is located between the minute plate branches 195. Is smaller than the width of the second open portion OP '. In other words, the second open portion corresponding to the space between the neighboring fine plate branch portions 195 than the width d of the first open portion OP corresponding to the space between the adjacent minute branch portions 194a ( OP ') has a wider width (d + d5). In this case, a portion extending from the first open portion OP to the second open portion OP 'may be gradually wider, and the fine branch branch 195 may be formed in the corresponding minute branch 194a. The portion leading to may have a shape that becomes relatively narrow in width.

In this embodiment, by reducing the width of the fine plate branch 195 to reduce the luminance reduction region, it is possible to obtain the effect of improving the luminance compared to the embodiment of FIGS.

The width reduction value d5 of the fine plate branch 195 may be about 10% to about 25% of the width d of the first open part OP.

9 and 10 are enlarged views showing the minute plate branch according to another embodiment of the present invention.

9 and 10, although substantially the same as the embodiment described with reference to FIGS. 6 to 8, the first open part OP extends toward the fine plate branch 195 to form the depression DP. . At this time, in the embodiment of FIG. 9, the depression DP is triangular, in particular an isosceles triangle shape, and in the embodiment of FIG. 10, the depression DP is trapezoidal, particularly isosceles trapezoidal.

If the inclination of the side surface extending from the fine branch portion 194a to the fine plate branch portion 195 is urgent, the liquid crystal may lie down in the direction in which the liquid crystal should originally lie, thereby generating a texture. However, as in the embodiments of FIGS. 9 and 10, by forming the depression DP, the slope of the side surface leading from the fine branch portion 194a to the fine plate branch portion 195 is smoothed at the fine plate branch portion 195. It is also possible to prevent the liquid crystal from lying down while improving the luminance of the liquid crystal.

FIG. 11 is a graph illustrating luminance according to position in the embodiment of FIG. 6. Specifically, the luminance according to the position is denoted as the first luminance in the V-W line of FIG. 7, and the luminance according to the position is denoted as the second luminance in the V′-W 'line of FIG. 7.

Referring to FIG. 11, the luminance change in the first open part OP between the plurality of minute branches 194a and the adjacent minute branches 194aa and 194ab is represented as the first brightness. The first luminance represents the maximum luminance in the fine branch portion 194a and the minimum luminance in the first open portion OP. Similarly, the luminance change in the second open portion OP 'between the plurality of fine plate branch portions 195 and the neighboring fine plate branch portions 195 is represented as the second luminance, and the second luminance is the fine plate branch. The unit 195 represents the maximum luminance, and the second open unit OP ′ represents the minimum luminance.

In this case, when the second luminance is examined in more detail, the luminance is slightly decreased at the central portion of the minute plate branch 195, but in the exemplary embodiment of FIGS. 1 to 3 as illustrated in FIG.

12 is a plan view illustrating a pattern of one subpixel electrode according to another exemplary embodiment of the present invention.

Referring to FIG. 12, similar to the pattern of the subpixel electrode described with reference to FIG. 7, the overall shape of the first subpixel electrode 191a is a quadrangle, and the vertical stem portion 192a and the horizontal stem portion 193a intersecting with the vertical stem portion 192a. It includes a cross stem made of. In addition, the first subpixel electrode 191a is divided into four subregions by the horizontal stem portion 193a and the vertical stem portion 192a, and each of the plurality of minute branches 194a extends in an oblique direction. ) And a plurality of fine plate branch portions 195. The width of the first open portion OP positioned between the minute branch portions 194a is smaller than the width of the second open portion OP ′ positioned between the fine plate branches 195.

However, the positions where the fine branch portions 194a and the fine plate branch portions 195 are formed are different from those described in FIG. 7. Specifically, in the present embodiment, the fine branch portion 194a extends from the horizontal stem portion 193a or the vertical stem portion 192a, and the fine plate branch portion 195 is connected to the end of the fine branch portion 194a. have. That is, the fine branch portions 194a are arranged at the center portion close to the cross stem portion, and the fine plate branch portions 195 are arranged along the edge portion of the first subpixel electrode 191a.

The overall shape of the fine branch portion 194a may be a rhombus, and may be vertically symmetrical with respect to the cross stem portion. Alternatively, the minute branches 194a may be square. The overall shape of the first subpixel electrode 191a is quadrangular, and the first subpixel electrode 191a has a first region in which the minute branch 194a is located and a second region in which the minute plate branch 195 is located. The second region where the minute plate branch 195 is located is substantially the same as the shape of the first subpixel electrode 191a minus the first region where the minute branch 194a is located. .

One end of the minute plate branch 195 is connected to each other by the edge pattern 450 at left and right edge portions of the first subpixel electrode 191a.

Except for the difference described above, the contents described with reference to FIG. 7 may be applied to the embodiment of FIG. 12.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

110 Lower Substrate 210 Upper Substrate
121 Gate line 124a, 124b gate electrode
192a, 192b vertical stem 193a, 193b horizontal stem
194a, 194b fine branch 195 fine mailing branch
197a, 197b Upper and Lower Protrusions 450 Border Pattern
BPL luminance peak line DP depression

Claims

First substrate,
A thin film transistor positioned on the first substrate;
A first electrode positioned on the thin film transistor and connected to an output electrode of the thin film transistor,
The first electrode includes a first region including a plurality of fine branch portions spaced apart from each other with a first open portion therebetween, and a portion of at least two fine branch portions of the plurality of fine branch portions are connected to each other to form one fine branch portion. A second area for forming a plurality of fine plate branch parts having a thick width,
The plurality of fine plate branch portions are spaced apart from each other with a second opening portion therebetween,
The width of the first opening and the width of the second opening is different from each other,
The first electrode includes a cross stem portion including a horizontal stem portion and a vertical stem portion crossing the horizontal stem portion,
The plurality of fine plate branch portions extend from the cross stem portion,
The first region is located at the edge of the first electrode, the second region is located between the first region and the cross stem portion,
The first opening portion extends toward one of the fine plate branch portions of the plurality of fine plate branch portions between two fine branch portions adjacent to each other of the plurality of fine branch portions to form a depression,
And the one minute plate branch part is formed by connecting a portion of the two minute branch parts to each other.

delete

In claim 1,
The depression is a triangular shape liquid crystal display device.

In claim 1,
The recessed portion has a trapezoidal shape.

In claim 1,
The width of the second opening is greater than the width of the first opening by 10% to 25% of the width of the first opening.

In claim 1,
And a portion of the first opening portion extending from the first opening portion to the second opening portion is gradually wider.

delete

In claim 1,
And a second region in which the plurality of minute plate branch portions are positioned to be symmetrical with respect to the cross stem.

In claim 8,
And the first electrode includes a plurality of regions having the plurality of minute plate branches or the minute branches extending in different directions from the cross stem.

In claim 9,
And the second region in which the plurality of minute plate branch portions are positioned is a square shape.

In claim 10,
And the minute branch portion extends from an end of the minute plate branch portion extending from the cross stem portion.

In claim 11,
And the minute plate branch portion forms an angle of 45 degrees with the horizontal stem portion or the vertical stem portion.

In claim 12,
And the horizontal stem portion and the vertical stem portion have different widths.

First substrate,
A thin film transistor positioned on the first substrate;
A first electrode positioned on the thin film transistor and connected to an output electrode of the thin film transistor,
The first electrode includes a first region including a plurality of fine branch portions spaced apart from each other with a first open portion therebetween, and a portion of at least two fine branch portions of the plurality of fine branch portions are connected to each other to form one fine branch portion. A second area for forming a plurality of fine plate branch parts having a thick width,
The plurality of fine plate branch portions are spaced apart from each other with a second opening portion therebetween,
The width of the first opening and the width of the second opening is different from each other,
The first electrode includes a cross stem portion including a horizontal stem portion and a vertical stem portion crossing the horizontal stem portion,
The plurality of fine branch portions extend from the cross stem portion,
The second region is located at an edge of the first electrode, and the first region is located between the second region and the cross stem portion,
The first opening portion extends toward one of the fine plate branch portions of the plurality of fine plate branch portions between two fine branch portions adjacent to each other of the plurality of fine branch portions to form a depression,
And the one minute plate branch part is formed by connecting a portion of the two minute branch parts to each other.

The method of claim 14,
And a second region in which the plurality of minute plate branch portions are positioned to be symmetrical with respect to the cross stem.

The method of claim 15,
And the first electrode includes a plurality of regions in which the fine branch portions or the plurality of fine plate branch portions extend in different directions from the cross stem portion.

The method of claim 16,
And the minute plate branch portion extends from an end of the minute branch portion extending from the cross stem portion.

The method of claim 17,
And the minute plate branch portion forms an angle of 45 degrees with the horizontal stem portion or the vertical stem portion.

The method of claim 18,
And the horizontal stem portion and the vertical stem portion have different widths.

In claim 1,
And a direction in which the minute branch portions and the minute plate branch portions extend in parallel to each other.

In claim 1,
A second substrate facing the first substrate and
Further comprising a second electrode positioned on the second substrate,
The second electrode is a plate-shaped liquid crystal display device.