KR100724484B1 - Liquid crystal display device and fabrication method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-domain vertical alignment mode liquid crystal display device capable of improving the aperture. The present invention relates to a liquid crystal display device comprising a first substrate, a second substrate opposed to the first substrate, and a liquid crystal layer positioned between the first substrate and the second substrate, wherein the liquid crystal display element crosses each other on the first substrate. A gate line and a data line formed to define a plurality of pixel regions; A liquid crystal control electrode line formed in the pixel region and having one region having a different width; A pixel electrode having a first slit formed in the pixel area to cover the liquid crystal control electrode line and partially overlapping the liquid crystal control electrode line formed to have a different width and a second slit formed so as not to overlap the liquid crystal control electrode line; It includes a plurality of first slits are characterized in that the liquid crystal control electrode lines formed to have a plurality of different widths are continuously spaced apart from each other at regular intervals so as to correspond to the extended region.

Multi Domain, Slit, Field Distortion, Opening Ratio

Description

Liquid crystal display device and its manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE AND FABRICATION METHOD THEREOF}

1 is a view schematically showing a cross section of a unit pixel in a multi-domain liquid crystal display device using a conventional slit,

2 is a view schematically showing a cross section of a unit pixel in a multi-domain liquid crystal display device using a projection.

3A and 3B illustrate a multi-domain liquid crystal display device according to a first embodiment of the present invention. FIG. 3A is a plan view schematically illustrating a unit pixel, and FIG. 3B is a cross-sectional view taken along line II ′ of FIG. 3A. Section,

4 is a view for explaining the viewing angle compensation principle according to the present invention,

5 is a cross-sectional view showing a liquid crystal control electrode formed in a region corresponding to a slit, in particular, the liquid crystal control electrode formed on a gate insulating film

6 is a plan view schematically showing a unit pixel for explaining a second embodiment of the present invention capable of improving light transmittance and aperture ratio,

7A to 7C are enlarged views of the first slit and the first liquid crystal control electrode line, FIG. 7A is an enlarged view of A in FIG. 6, FIG. 7B is a cross-sectional view of II-II ′ of FIG. 7A, and FIG. 7C Is a cross-sectional view of III-III 'of FIG. 7A,

FIG. 8 is a diagram illustrating an equipotential line in a pixel including an area corresponding to FIG. 7A.

9A and 9B are images showing light leakage regions in a black mode and light blocking regions in a white mode, respectively.

10 and 11 are views showing the third and fourth embodiments according to the present invention, respectively.

12A to 12C are process plan views illustrating a method of manufacturing a liquid crystal display device according to a second embodiment.

*** Explanation of symbols for main parts of drawing ***
110: first substrate 101: gate line
102a: source electrode 102b: drain electrode
103: data line 105: semiconductor layer
107: drain contact hole 109: thin film transistor
111: liquid crystal control electrode line 113: pixel electrode
114: slit 120: second substrate
121: Black matrix 123: Color filter
125: common electrode 211a: first liquid crystal control electrode line
211b: second liquid crystal control electrode line 214a: first slit

214b: second slit

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The present invention relates to a liquid crystal display device, and more particularly, to a multi-domain liquid crystal display device and a method of manufacturing the same to realize a wide viewing angle and improve aperture ratio.

Liquid crystal display devices are mainly used as flat panel display devices having high quality and low power. The liquid crystal display device is bonded so that the thin film transistor array substrate and the color filter substrate face each other at uniform intervals, and a liquid crystal layer is formed between the thin film transistor array substrate and the color filter substrate.

In the thin film transistor array substrate, pixels are arranged in a matrix form, and a thin film transistor, a pixel electrode, and a capacitor are formed in a unit pixel, and the color filter substrate is a common electrode and an actual color for applying an electric field to the liquid crystal layer together with the pixel electrode. An RGB color filter and a black matrix are formed to implement the.

On the other hand, an alignment layer is formed on the opposite surface of the thin film transistor array substrate and the color filter substrate, and rubbing is performed so that the liquid crystal layer is arranged in a constant direction. In this case, the liquid crystal is rotated by dielectric anisotropy when an electric field is applied between the pixel electrode formed for each unit pixel of the thin film transistor array substrate and the common electrode formed on the front surface of the color filter substrate, thereby passing or blocking light per unit pixel. Characters or images are displayed. However, the above-described twisted nematic mode liquid crystal display device has a disadvantage in that the viewing angle is narrow. This is due to the refractive anisotropy of the liquid crystal molecules. In the TN mode, light transmittance is symmetrically distributed in the left and right viewing angles, but light transmittance is asymmetrically distributed in the vertical direction. In the viewing angle, an inverted range of the image is generated to narrow the viewing angle.

In order to solve the viewing angle problem, a film compensation mode for compensating the viewing angle with a compensation film, a multi-domain mode for compensating the viewing angle by dividing a pixel into multiple domains and changing the viewing angle of each domain, and two on the same substrate Background Art A liquid crystal display device such as a horizontal electric field mode in which an electrode is formed to form a horizontal electric field, and an OCB mode (Optically Compensated Birefringence Mode) has been proposed.

On the other hand, the vertical alignment (VA) mode liquid crystal display uses a negative type liquid crystal having a negative dielectric anisotropy and a vertical alignment layer. In the state where no voltage is applied, the long axes of the liquid crystal molecules are vertically aligned with the plane of the alignment layer. The polarization axis of the polarizer attached to the substrate is arranged perpendicular to the long axis of the liquid crystal molecules so as to display a normally black mode. On the other hand, when a voltage is applied, the long axis of the liquid crystal molecules is shifted from the vertical direction of the alignment film plane to the alignment film plane to transmit light due to the property of being oriented obliquely with respect to the electric field of the negative liquid crystal molecule.

Such a vertically aligned liquid crystal display device forms a structure or a slit such as a side electrode, a rib, or the like on a substrate, thereby distorting an electric field generated in the liquid crystal layer so that the director of the liquid crystal molecules is desired. Can be positioned in a direction. Examples include Pattern Vertical Alignment (PVA), Multi-damain Vertical Alignment (MVA), and the like.

1 and 2 schematically illustrate a cross-section of a unit pixel of a vertical alignment mode liquid crystal display device having an improved viewing angle using a conventional multi-domain. FIG. 1 shows only a slit as an electric field distortion means. 2 is a liquid crystal display device, and FIG. 2 is a liquid crystal display device using projections.

As shown in the figure, the conventional vertical alignment mode liquid crystal display device liquid crystal display device 10, the first and second substrates (1, 2), and the first substrate 1 and the second It consists of the liquid crystal layer 9 formed between the board | substrates 2. As shown in FIG.

Although not shown in detail in the drawing, a plurality of gate lines and data lines are formed on the first substrate 1 to be arranged horizontally and horizontally to define a pixel area, and a thin film transistor is formed at an intersection of the gate lines and the data line. Formed. In the pixel region, a pixel electrode 3 electrically connected to the thin film transistor is formed.

The common electrode 4 is formed on the second substrate 2 to generate an electric field together with the pixel electrode 3 to drive the liquid crystal molecules 9. In addition, although not shown in detail in the drawings, a color filter for implementing a black matrix and color to block light leaking from the gate / data line and the thin film transistor is formed.

In addition, slits 6a and 6b are formed in the pixel electrode 3 and the common electrode 4 to cause electric field distortion.

The slits 6a and 6b formed in the pixel electrode 3 and the common electrode 4 distort the electric field formed between the pixel electrode 3 and the common electrode 4, thereby dividing the domain into several regions. In this case, you will implement a multi-domain. In this case, the protrusion 8 may be formed on the second substrate 2 (see FIG. 2).

In the conventional liquid crystal display device configured as described above, when a voltage equal to or greater than a threshold is applied to the pixel electrode 3 and the common electrode 4, the liquid crystal molecules whose long axes are arranged perpendicular to the substrate plane are inclined in the horizontal direction. In this case, the electric field is distorted by the action of the slit 6b or the projection 8 so that the liquid crystal molecules are arranged in different directions with respect to the slit 6b or the projection 8. As a result, the liquid crystal directors face each other and the viewing angle is compensated, thereby realizing a wide viewing angle.

However, in the conventional liquid crystal display device, when the first and second substrates are not bonded correctly, when the positions of the slits formed on the pixel electrode and the slits or projections formed on the common electrode are shifted, the area ratio of the domain is changed so that the viewing angle characteristic is deteriorated. There was a problem of poor display quality.

Accordingly, the present invention has been devised to solve the above problems, and an object of the present invention is to provide a liquid crystal display device capable of preventing deterioration of viewing angle characteristics due to misalignment of the first substrate and the second substrate. It is to provide a manufacturing method.

Another object of the present invention is to provide a multi-domain liquid crystal display device and a method of manufacturing the same, by forming a slit and a liquid crystal control electrode line which are means for distorting an electric field only on a second substrate.

In addition, another object of the present invention is to provide a multi-domain liquid crystal display device having an improved aperture ratio by reducing the formation area of the liquid crystal control electrode line, and a method of manufacturing the same.

The above object is, according to the present invention, a liquid crystal display device comprising a first substrate, a second substrate facing the first substrate and a liquid crystal layer positioned between the first substrate and the second substrate. A gate line and a data line formed to cross each other on one substrate to define a plurality of pixel regions; A liquid crystal control electrode line formed in the pixel region and having one region having a different width; A pixel electrode having a first slit formed in the pixel area to cover the liquid crystal control electrode line and partially overlapping the liquid crystal control electrode line formed to have a different width and a second slit formed so as not to overlap the liquid crystal control electrode line; And a plurality of first slits provided in a plurality of first slits, and arranged to be spaced apart from each other at regular intervals so as to correspond to a region in which the width is extended. Is achieved.
The liquid crystal control electrode line may include a second liquid crystal control electrode line formed along an edge of the pixel region, and a first liquid crystal control electrode line provided inside the second liquid crystal control electrode line.
In addition, the first liquid crystal control electrode line is provided to have a different width, the width portion of the first liquid crystal control electrode line is provided to correspond to the first slit, the width of the first liquid crystal control electrode line The narrowed portion may be provided to correspond to the region between the first slits.
In addition, the liquid crystal control electrode line may be formed of the same material as the gate line.
Here, the liquid crystal control electrode line may be formed of the same material as the data line.
The first slit is formed along the first liquid crystal control electrode line to partially overlap the first liquid crystal control electrode line, and the second slit is formed of the first liquid crystal control electrode line and the second liquid crystal control electrode. It can be located in the area between the lines.
In addition, the first slit has a vertical length greater than the horizontal length, the first slit may be arranged such that the longitudinal length of the first slit side by side in the arrangement direction of the plurality of first slit.
Here, the plurality of first slits may be formed such that the distance between the first slits is smaller than the longitudinal length of the first slits.
In addition, the plurality of first slits may be formed such that a distance between the first slits is smaller than or substantially equal to a horizontal length of the first slits.
In addition, the liquid crystal control electrode line and the first and second slits may be provided in a bent structure.
The method may further include a connection pattern interconnecting the liquid crystal control electrode lines formed in the pixel areas.
When the pixel voltage applied to the pixel electrode is the negative voltage V _{p (−)} , the voltage applied to the liquid crystal control electrode line is the minimum electric field distortion voltage lower than the negative pixel voltage V _{p (−)} . When V _min is applied and the pixel voltage applied to the pixel electrode is the bipolar voltage V _{p (+)} , the voltage applied to the liquid crystal control electrode line is greater than the bipolar pixel voltage V _{p (+)} . A high maximum field distortion voltage V _max can be applied.
SUMMARY OF THE INVENTION An object of the present invention is a liquid crystal display device comprising, according to the present invention, a first substrate, a second substrate facing the first substrate and a liquid crystal layer positioned between the first substrate and the second substrate. A method of manufacturing a semiconductor device, the method comprising: forming a liquid crystal control electrode line on a first substrate such that one region has a different width; Forming a transparent conductive film to cover the liquid crystal control electrode line; Patterning the transparent conductive film to form a pixel electrode having a first slit formed to partially overlap with the liquid crystal control electrode line formed to have a different width and a second slit formed so as not to overlap the liquid crystal control electrode line; The plurality of first slits may be arranged to be continuously spaced apart from each other at regular intervals so as to correspond to a region where the width of the liquid crystal control electrode lines is formed to have a different width. It is achieved by the manufacturing method.
Forming a gate line on the first substrate; The method may further include forming a data line formed on the gate line to intersect the gate line and defining a plurality of pixel regions, wherein the liquid crystal control electrode line may be formed simultaneously with the gate line.
Forming a gate line on the first substrate; The method may further include forming a data line formed on the gate line to intersect the gate line to define a plurality of pixel regions, wherein the liquid crystal control electrode line may be formed simultaneously with the data line.
The liquid crystal control electrode line may include a second liquid crystal control electrode line formed along an edge of the pixel region, and a first liquid crystal control electrode line provided inside the second liquid crystal control electrode line. The lines may be provided to have different widths.
The liquid crystal control electrode line is provided such that an extended portion of the first liquid crystal control electrode line corresponds to the first slit, and a portion of the first liquid crystal control electrode line that is narrower between the first slits. It may be provided to correspond to an area.

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Hereinafter, a multi-domain liquid crystal display device and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.
Hereinafter, the present invention will be described in detail with reference to the drawings.
First, the multi-domain liquid crystal display device according to the first embodiment of the present invention will be described in detail with reference to FIGS. 3A and 3B. 3A and 3B illustrate a multi-domain liquid crystal display device according to the present invention. FIG. 3A is a plan view showing a unit pixel, and FIG. 3B is a cross-sectional view taken along line II ′ of FIG. 3A.
As shown in the figure, the multi-domain liquid crystal display device 100 of the present invention, as shown in Figure 3b, the first and second substrates 110, 120, and the first substrate 110 and the first The liquid crystal layer 119 formed between the two substrates 120 is included.
As shown in FIG. 3A, a plurality of gate lines 101 and data lines 103 are formed on the first substrate 110 to be arranged to cross each other to define a pixel area, and the gate lines 101 are formed on the first substrate 110. ) And a thin film transistor 109 are formed at the intersection of the data line 103.
The thin film transistor 109 includes a gate electrode formed as a part of the gate line 101, a semiconductor layer 105 formed on the gate line 101, and a source and drain electrode 102a formed on the semiconductor layer 105. , 102b). Here, the gate electrode may be part of the gate line 101 as shown in FIG. 3A, or may be separately drawn from the gate line 101 although not shown.
In addition, a pixel electrode 113 is formed in the pixel region, and the pixel electrode 113 is electrically connected to the drain electrode 102b through a drain contact hole 107, and is configured to distort an electric field. Has a slit 114. That is, a plurality of slits 114 formed by removing a part of the pixel electrode 113 are formed in the pixel electrode 113. The slit 114 according to the present invention may be formed at the same time during the patterning process of the pixel electrode 113. The slit 114 according to the first embodiment of the present invention is formed long along the extending direction of the data line 103. Specifically, three slits 114 are arranged in parallel with each other, and the slits 114 located at the center thereof are formed at positions overlapping with the first liquid crystal control electrode line 111 a and two slits located at both sides. Are positioned between the first liquid crystal control electrode line 111a and the second liquid crystal control electrode line 111b. The slit 114 according to the present invention is for dividing the liquid crystal layer 119 into a plurality of domains by distorting an electric field formed between the pixel electrode 113 and the common electrode 125.
In addition, a liquid crystal control electrode line 111 is formed on the first substrate 110 to form a plurality of domains by distorting an electric field together with the slit 114. The liquid crystal control electrode line 111 according to the present invention is positioned between the first substrate 110 and the gate insulating film 115, as shown in FIG. 3B. Specifically, since the liquid crystal control electrode line 111 according to the present invention is formed simultaneously with the formation of the gate line 101, the liquid crystal control electrode line 111 is made of the same material as the gate line 101. In a modified embodiment, the liquid crystal control electrode line 111 may be formed on the gate insulating film 115 as shown in FIG. 5. That is, the liquid crystal control electrode line 111 according to the modified embodiment may be formed of the same material at the same time as the data line 103. In this case, the liquid crystal control electrode line 111 may include the gate insulating film 115 and the protective film 117. The liquid crystal control electrode line 111 according to the present invention includes a second liquid crystal control electrode line 111b formed along an edge of the pixel region, as shown in FIG. The first liquid crystal control electrode line 111b is provided between the second liquid crystal control electrode line 111b. That is, the second liquid crystal control electrode line 111b is provided in a substantially rectangular shape, and the first liquid crystal control electrode line 111a extends along the data line 103 to be connected to both sides of the second liquid crystal electrode line 111b. The liquid crystal control electrode line 111 has a shape similar to that of the number arm 8 lying down as a whole. The second liquid crystal control electrode line 111b is formed outside the pixel area adjacent to the data line 103 in order to effectively block the influence of the signal of the data line 103 on the pixel electrode 113. The first liquid crystal control electrode line 111a is provided to divide the liquid crystal layer 119 into a plurality of domains, and the electric field generated in the first liquid crystal control electrode line 111a controls the liquid crystal layer 119. Control to be symmetrically arranged around the electrode line (111a).
Meanwhile, a black matrix 121 is formed on the second substrate 120 to block light leaking from the gate line 101, the data line 103, and the thin film transistor 109. The filter 123 is formed. A common electrode 125 is formed on the color filter 123 to generate an electric field together with the pixel electrode 113 to drive the liquid crystal layer 119. The pixel electrode 113 and the common electrode 125 are formed on the color filter 123. ) Is formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).
In the liquid crystal display device configured as described above, when the voltage greater than or equal to the threshold is applied to the pixel electrode 113 and the common electrode 125, the liquid crystal molecule 119 is generated by the pixel electrode 113 and the common electrode 125. It is driven by an electric field (indicated by a dotted line on the drawing). In this case, the electric field generated between the pixel electrode 113 and the common electrode 125 is formed by the liquid crystal control electrode line 111 formed on the first substrate 110 and the slit 114 formed on the pixel electrode 113. It is symmetrical with respect to the first liquid crystal control electrode line 111a. Therefore, the liquid crystal molecules forming the liquid crystal layer 119 arranged along the electric field direction are symmetrical about the first liquid crystal control electrode line 111a.
As such, the liquid crystal molecules constituting the liquid crystal layer 119 form a symmetrical arrangement by the first liquid crystal control electrode line 111 a and the slit 114, thereby realizing a plurality of domains, thereby improving the viewing angle. . That is, as shown in FIG. 4, in the case of two domains in which the liquid crystal molecules are symmetrical to each other, the birefringence value of a1 of the first liquid crystal molecule 119a is determined by the value of the first liquid crystal molecule 119a. The birefringence value of a2 of the second liquid crystal molecules 119b taking the molecular array in the opposite direction is compensated, and as a result, the birefringence value becomes about zero. In addition, the birefringence value of c1 is compensated by c2. Therefore, the present invention can prevent the deterioration of the image quality according to the viewing angle through the viewing angle compensation by forming the multi-domain.
In addition, according to the present invention, the liquid crystal control electrode line 111 and the slit 114, which are means for dividing the liquid crystal layer 119 into a plurality of domains by distorting an electric field formed between the pixel electrode 113 and the common electrode 125, Since both are formed on the first substrate 110, it is possible to prevent the viewing angle characteristic caused by the misalignment of the first substrate 110 and the second substrate 120 from being lowered. In other words, the conventional slits or protrusions are formed on the first substrate and the second substrate, respectively, and the area of the domains symmetrical to each other is changed by misalignment generated when the first substrate and the second substrate are bonded to each other. Accordingly, there was a problem that the viewing angle characteristic is lowered.
On the other hand, according to the present invention, since the liquid crystal control electrode line 111 and the slit 114 are formed on the first substrate 110, the domain region due to misalignment of the first substrate 110 and the second substrate 120 is formed. Asymmetry can be prevented, whereby the viewing angle characteristic can be prevented from being lowered and a wide viewing angle can be realized.
As described above, in order to form a domain having an array of liquid crystal molecules symmetrical with respect to the first liquid crystal control electrode line 111a, a common voltage (V) of approximately 3.3 V is applied to the common electrode 125. _com Is applied to the pixel electrode 113, the pixel voltage (V) for adjusting the light transmission amount. _p ) Is applied, and a low gate voltage (V) of approximately -5V is applied to the liquid crystal control electrode line 111. _gl ) Is applied.
However, since the liquid crystal deteriorates characteristic when the DC voltage is applied for a long time, the applied voltage, that is, the pixel voltage (V). _p Periodically change the polarity of) to drive. However, the signal of the pixel voltage is bipolar (V). _{p (+)} And the signal of the liquid crystal control electrode line 111 is a low gate voltage (V). _gl ; -5V), the arrangement of the liquid crystal molecules does not form a symmetrical domain with respect to the liquid crystal control electrode line 111. That is, the liquid crystal molecules are not arranged in a direction facing each other with respect to each domain on the boundary of the liquid crystal control electrode line 111, and the liquid crystal molecules are arranged in the opposite direction near the liquid crystal control electrode line 111. Will occur.
Accordingly, in the present invention, in order to solve this problem, the signal of the liquid crystal control electrode line 111 is applied to match the polarity of the pixel voltage. In other words, when the signal of the pixel voltage is negative, the pixel voltage V _{p (-)} Liquid crystal control signal lower than V _min ) Is applied to the liquid crystal control electrode line 111, and the pixel voltage (V) when the signal of the pixel voltage is bipolar. _{p (+)} Liquid crystal control signal (V) higher than _max ) Is applied to the liquid crystal control electrode line 111. That is, the minimum liquid crystal control signal V applied when the signal of the pixel voltage is negative in order to make the domains of the same arrangement of liquid crystal molecules symmetrical with respect to the liquid crystal control electrode line 111. _min ) And pixel voltage (V) _{p (-)} Voltage difference between _{p (-)} -V _min Is the maximum liquid crystal control signal V when the signal of the pixel voltage is bipolar. _max ) And pixel voltage (V) _{p (+)} Voltage difference between _max -V _{p (+)} ) Must satisfy the same conditions.
The polarity inversion driving method includes frame inversion, line inversion, dot inversion, and the like. In the case of dot inversion driving, the pixel voltage signal is alternately applied to the pixel voltage signal for each pixel. Therefore, the liquid crystal control signal in the case of dot inversion driving is the minimum liquid crystal control signal (V) for each pixel. _max ) And maximum liquid crystal control signal should be alternately applied.
On the other hand, the shape of the liquid crystal control electrode line 111 and the slit 114 according to the first embodiment of the present invention is not limited to a specific shape as shown, it can be variously modified, such as zigzag shape.
Although not shown in the drawings, a connection pattern for electrically connecting the liquid crystal control electrode line 111 between neighboring pixels and applying a liquid crystal control signal is formed separately, and the connection pattern is the gate line 101. It may be formed to be parallel to or parallel to the data line 103. That is, when the liquid crystal control electrode line 111 is formed on the same plane as the gate line 101, the liquid crystal control electrode line 111 is formed parallel to the gate line 101, and when the liquid crystal control electrode line 111 is formed on the same plane as the data line 103. The connection pattern should be formed in parallel with the data line 103.
As described above, the present invention forms the liquid crystal control electrode line 111 and the slit 114 on the same first substrate 110, and the same according to the polarity of the pixel voltage applied to the pixel electrode 113. By applying a liquid crystal control signal applied to the liquid crystal control electrode line 111, the viewing angle characteristic due to misalignment of the first substrate 110 and the second substrate 120 is prevented from being lowered, and the first liquid crystal control electrode The domain divided by the line 111a is symmetrical to effectively implement the wide viewing angle.
However, since the liquid crystal control electrode line 111 is formed of an opaque metal, there is a problem that the aperture ratio is lowered. In particular, under the black condition, the same common voltage is applied to the pixel electrode 113 and the common electrode 125, and the maximum liquid crystal control signal V is applied to the liquid crystal control electrode line 111. _max ) Is applied, and light leakage occurs around the slit due to the signal applied to the liquid crystal control electrode line 111. As such, in order to prevent light leakage in the black condition, the width of the liquid crystal control electrode line 111 should be formed sufficiently wide, and thus there is a problem that the aperture ratio is reduced.
5 is a cross-sectional view illustrating a liquid crystal control electrode formed in a region corresponding to the slit 114, in particular, the liquid crystal control electrode line 111 is formed on the gate insulating film 115. That is, FIG. 5 is a cross-sectional view when the liquid crystal control electrode line 111 is formed at the same time as the data line 103 as in the modified embodiment.
As shown in FIG. 5, the liquid crystal control electrode line 111 is formed so as to overlap a predetermined interval on both sides of the slit 114 and the adjacent pixel electrode 113 with the passivation layer 117 therebetween. The reason why both sides of the liquid crystal control electrode line 111 and the pixel electrode 113 overlap with each other is to prevent light leakage from both sides (areas adjacent to the slit) of the pixel electrode 113 under the black condition. will be. Specifically, when the liquid crystal control electrode line 111 is formed smaller than the width of the slit 114, light leakage may occur at both sides of the pixel electrode 113 on which the slit 114 is formed. In order to prevent such light leakage, all the areas where light leakage occurs are blocked by the liquid crystal control electrode 111. Accordingly, both sides of the liquid crystal control electrode line 111 are formed to overlap both sides of the pixel electrode 113 on which the slit 114 is formed, and the overlap distance L is about 2 to 3 μm. As such, as the width of the liquid crystal control electrode line 111 increases in order to block light leakage under the black condition, a problem occurs that the aperture ratio decreases.
The present invention has been made in particular to solve this problem, and provides a multi-domain liquid crystal display device capable of improving the light transmittance by modifying the shape of the liquid crystal control electrode line and the slit to minimize the decrease in the aperture ratio. That is, the light transmittance is improved by forming elliptical slits continuously disposed at a predetermined distance and reducing the formation area of the liquid crystal control electrode line corresponding to the separation distance between the slits.
Hereinafter, a second embodiment of the present invention which can minimize the above-described problem will be described with reference to FIG.
In the second embodiment, only the structures of the liquid crystal control electrode lines and the slits are different from those of the first embodiment, and other components are the same as in the first embodiment.
As shown in FIG. 6, in the liquid crystal display device 200 according to the second exemplary embodiment, a pixel region is defined by vertically crossing a gate line 201 and a data line 203 on a first substrate 210. The switching element 209 for switching each pixel is formed in the intersection area.
The pixel electrode 213 is formed in the pixel region. The pixel electrode 213 is electrically connected to the drain electrode 202b through the drain contact hole 207. A slit 214 is formed in the pixel electrode 213 to distort an electric field, and the slit 214 according to the second embodiment of the present invention is positioned at a position overlapping the first liquid crystal control electrode line 211a. The first slit 214a is formed, and the second slit 214b is disposed between the first liquid crystal control electrode line 211a and the second liquid crystal control electrode line 211b. The slit 214 according to the present invention is formed by removing a part of the pixel electrode 213. In addition, the first slit 214a is a first slit 214a which is a means for distorting an electric field together with the first slit 214a. A liquid crystal control electrode line 211a is formed, and a second liquid crystal control electrode line 211b that blocks a signal of the data line 203 is formed outside the pixel area. Here, the second liquid crystal control electrode line 211b is the same as the second liquid crystal control electrode line 111b (see FIG. 3A) of the first embodiment described above. The second slits 214b are slits 114 respectively positioned between the first liquid crystal control electrode lines 111a (see FIG. 3A) and the second liquid crystal control electrode lines 111b (see FIG. 3A) in the above-described first embodiment. 3a).
Meanwhile, as illustrated in FIG. 6, the first slit 214a is formed by removing the pixel electrode 213 substantially in the shape of a hole in an ellipse. The first slits 214a according to the present invention are arranged in a line on a straight line at regular intervals, and the first liquid crystal control electrode line 211a is positioned at a distance corresponding to the separation distance of the first slit 214a. It has a shape that decreases in width.
Hereinafter, the first slit 214a and the first liquid crystal control electrode line 211a according to the second embodiment of the present invention will be described in detail with reference to FIGS. 7A to 7C.
7A to 7C are enlarged views of the first slit 214a and the first liquid crystal control electrode 211a. FIG. 7A is an enlarged view of A in FIG. 6, and FIGS. 7B and 7C are II- of FIG. 7A. Sectional drawing of II 'and III-III'.
First, as shown in FIG. 7A, the first slits 214a have an elliptical hole shape, and the plurality of first slits 214a are arranged in a line spaced apart from each other at a predetermined interval D1. Here, the first slit 214a is an ellipse formed long in the extending direction of the data line 203 (see FIG. 6), and the vertical length D2 and the horizontal length D3 are different from each other. That is, the length (vertical length) of the 1st slit 214a in the arrangement direction is formed longer. The separation distance D1 between the first slit 214a may be smaller than the vertical length D2 of the first slit 214a, and may be smaller than or equal to the horizontal length D3 of the first slit 214a. have.
In addition, the first liquid crystal control electrode line 211a formed below the first slit 214a is formed in a similar shape to the first slit 214a. Specifically, the width is extended at the position corresponding to the first slit 214a, and the width is narrow at the position corresponding to the separation region of the first slit 214a. That is, the first liquid crystal control electrode line 211a is provided in a straight line as a whole, but its width is different from each other. Specifically, the width of the first liquid crystal control electrode line 211a in a region where the first slits 214a are spaced apart from each other, that is, a region corresponding to the length of D1, is smaller in width than that corresponding to the first slit 214a. Formed. As the widths of the first liquid crystal control electrode line 211a are different from each other, it means that the formation area of the first liquid crystal control electrode line 211a is reduced compared to the first embodiment, and the first liquid crystal control electrode line The opening ratio is increased by the area T where the width of the 211a is narrowed.
That is, in the present embodiment, the first slits 214a having an elliptical length longer than the horizontal length are arranged at regular intervals, and the width of the first liquid crystal control electrode line 211a formed at the lower portion thereof is the first slit 214a. By narrowing the gap between the gaps, the area of the first liquid crystal control electrode line 211a formed in the gap between the first slits 214a is reduced, thereby improving the aperture ratio.
7A and 7B, the first liquid crystal control electrode line 211a and the second liquid crystal control electrode line 211b are formed on the first substrate 210, and the first liquid crystal A gate insulating film 215 and a protective film 217 are formed on the control electrode line 211a and the second liquid crystal control electrode line 211b. That is, the liquid crystal control electrode line 211 is formed of the same material as the gate line 201. The pixel electrode 213 is formed on the passivation layer 217. Although not specifically illustrated, the first liquid crystal control electrode line 211a and the second liquid crystal control electrode line 211b may be formed on the gate insulating layer 215. That is, the first liquid crystal control electrode line 211a and the second liquid crystal control electrode line 211b may be formed of the same material at the same time as the data line 203.
As described above, in the present embodiment, the plurality of first slits 214a are formed in the same shape as the holes of the plurality of ellipses, and the shape of the first liquid crystal control electrode line 211a formed thereunder is defined. Deformation is improved to improve the aperture ratio, but the separation area of the first slit 214a is designed to be smaller than the longitudinal length of the first slit 214a, and the same as or smaller than the horizontal length of the first slit 214a.
As described above, when the elliptical first slits 214a are continuously formed, an electric field different from the linear second slits 214b is generated. However, the remaining electric field except for the spaced area of the first slit 214a is formed with the same electric field as in the first embodiment, and the area around the first slit 214a is blocked by the first liquid crystal control electrode line 211a. It doesn't matter. That is, where the first slit 214a is located, an electric field is generated in the same manner as in the first embodiment, and an electric field of a type different from that of the first embodiment is generated in the region between the first slit 214a. However, the plurality of first slits 214a are ovals having a longitudinal length D2 longer than the horizontal length D3, and are arranged in a line along the extension direction of the data line 203, so that the entirety of the first slits 214a is the same as the first embodiment. The shape of the electric field is implemented. On the other hand, even if an electric field is formed in the region between the first slits 214a unlike the first embodiment, this region is blocked by the first liquid crystal control electrode line 211a, so no problem occurs. As a result, the liquid crystal molecules forming the liquid crystal layer 219 are symmetrically arranged at both sides with respect to the first liquid crystal control electrode line 211a, and are divided into a plurality of domains. Accordingly, the wide viewing angle can be effectively implemented by symmetrical domains divided based on the first liquid crystal control electrode line 211a.
FIG. 8 illustrates an equipotential line in a pixel including an area corresponding to FIG. 7A, and FIGS. 9A and 9B are images showing light leakage regions in a black mode and light blocking regions in a white mode, respectively.
First, as shown in FIG. 8, an equipotential line is formed around the first slit 214a and an electric field (not shown) is generated in a direction perpendicular to the equipotential line. Then, the liquid crystal molecules 219a are driven in the electric field direction. As shown in FIG. 9A, light leakage occurs around the first slit 214a in the black mode, and as shown in FIG. 9B. Likewise, in the white mode, an area in which light is blocked is generated around the first slit 214a. At this time, the light leakage area and the light blocking area around the first slit 214a are areas covered by the first liquid crystal control electrode line 214a.
10 and 11 show another embodiment of the present invention, in which all configurations except for the shape of the liquid crystal control electrode lines and slits are the same as in the second embodiment.
First, as shown in FIG. 10, the liquid crystal display device 300 according to the third exemplary embodiment of the present invention may include a gate line 301 and a data line defining a pixel area vertically and horizontally on the first substrate 310. 303 is formed, and a pixel electrode 313 is formed in the pixel region. In addition, a plurality of first and second slits 314a and 314b are formed in the pixel electrode 313 as a means for distorting an electric field. In this case, the first slit 314a is shaped like an ellipse hole, and a plurality of first slits 314a are continuously disposed along the extending direction of the gate line 301.
In addition, on the first substrate 310 corresponding to the first slit 314a, the width of the first liquid crystal control electrode line 311a decreases in a region corresponding to the spaced apart area between the first slits 314a. And a second liquid crystal control electrode line 311b that effectively blocks an influence of the signal of the data line 303 on the pixel electrode 313 is formed outside the pixel area adjacent to the data line 303. have. The first and second liquid crystal control electrode lines 311a and 311b may be formed on the same plane as the gate line 301 or the data line 303.
Although not shown in the drawings, as described in the first embodiment, a second substrate including a color filter, a black matrix, and a common electrode is formed, and a liquid crystal layer is formed between the first substrate and the second substrate. It is.
In the liquid crystal display device configured as described above, when voltage is applied to the pixel electrode 313 and the common electrode and the first and second liquid crystal control electrode lines 311a and 311b, respectively, the liquid crystal molecules of the liquid crystal layer are divided. The long axis of the liquid crystal molecules in the region forms a continuous domain, which is arranged to face the first slit 314a.
In addition, the first and second slits 314a and 314b and the first and second liquid crystal control electrode lines 311a and 311b form liquid crystal molecules in successive domains in each divided region, and may improve viewing angle characteristics. To distort the electric field. In this case, the liquid crystal control signals applied to the first and second liquid crystal control electrode lines 311a and 311b should be changed according to the polarity of the pixel voltage applied to the pixel electrode 313.
That is, when the signal of the pixel voltage is negative, the pixel voltage (V) _{p (-)} Liquid crystal control signal lower than V _min ) Is applied to the first and second liquid crystal control electrode lines 311a and 311b, and the signal of the pixel voltage is bipolar (V). _{p (+)} ), The pixel voltage (V) _{p (+)} Liquid crystal control signal (V) higher than _max ) Is applied. Even at this time, the minimum liquid crystal control signal (V) _min ) And pixel voltage (V) _{p (-)} Voltage difference between _{p (-)} -V _min ) And maximum liquid crystal control signal (V) _max ) And pixel voltage (V) _{p (+)} Voltage difference between _max -V _{p (+)} ) Must satisfy the same conditions.
As shown in FIG. 11, the liquid crystal display device 400 according to the fourth exemplary embodiment of the present invention may include a gate line 401 and a data line defining a pixel area vertically and horizontally on the first substrate 410. 403 is formed, and a pixel electrode 413 is formed in the pixel region. In addition, a plurality of first and second slits 414a and 414a are formed in the pixel electrode 413 to distort an electric field, and the first and second slits 414a and 414b have a zigzag shape. In particular, the first slit 414a is shaped like a hole of an ellipse, and is formed by continuously arranging a plurality of first slits 314a in a zigzag form of the gate line 301. do.
In the pixel region, first and second liquid crystal control electrode lines 411a and 411b are formed to distort an electric field together with the first and second slits 414a and 414b to form a multi-domain. The first and second liquid crystal control electrode lines 411a and 411 have the same bending structure as the first and second slits 414a and 414b. In the present embodiment, the four-domain is realized by forming the first and second slits 414a and 414b and the first and second liquid crystal control electrode lines 411a and 411b in a bent structure.
In this case, the first liquid crystal control electrode 411a is formed such that the width of the region between the first slit 414a and the region corresponding to the region of the first slit 414a is narrow. The second liquid crystal control electrode line 411b is formed outside the pixel region adjacent to the data line 403 to effectively block the influence of the signal of the data line 403 on the pixel electrode 413. The first and second liquid crystal control electrode lines 411a and 41b may be formed on the same plane as the gate line 401 or the data line 403.
Although not shown in the drawings, as described in the first embodiment, a second substrate including a color filter, a black matrix, and a common electrode is formed, and a liquid crystal layer is formed between the first substrate and the second substrate. It is.
In the liquid crystal display device configured as described above, when voltage is applied to the pixel electrode 413 and the common electrode, and the first and second liquid crystal control electrode lines 411a and 411b, respectively, the liquid crystal molecules of the liquid crystal layer Based on the first and second liquid crystal control electrode lines 411a and 411b, 4-domains having the same arrangement of liquid crystal molecules are formed.
The first and second liquid crystal control electrode lines 411a and 411b may be used to form the same arrangement of liquid crystal molecules based on the polarity of the pixel voltage applied to the pixel electrode 413. The liquid crystal control signal applied to the second liquid crystal control electrode lines 411a and 411b should be changed.
That is, when the signal of the pixel voltage is negative, the pixel voltage (V) _{p (-)} Lower liquid crystal control signal (Vmin) is applied to the first and second liquid crystal control electrode lines (411a, 411b) and the signal of the pixel voltage is bipolar (V). _{p (+)} ), The pixel voltage (V) _{p (+)} Liquid crystal control signal (V) higher than _max ) Is applied. Even at this time, the minimum liquid crystal control signal (V) _min ) And pixel voltage (V) _{p (-)} Voltage difference from _{p (-)} -V _min ) And maximum liquid crystal control signal (V) _max ) And pixel voltage (V) _{p (+)} Voltage difference from _max -V _{p (+)} ) Must satisfy the same conditions.
Meanwhile, in other embodiments of the present invention illustrated in FIGS. 10 and 11, a connection pattern for electrically connecting the liquid crystal control electrode lines between neighboring pixels is formed separately, and the connection pattern is parallel to the gate line. Or parallel to the data line.
12A to 12C are process plan views showing a method for manufacturing a multi-domain liquid crystal display device according to the present invention, and particularly, a method for manufacturing a liquid crystal display device according to a second embodiment of the present invention.
First, as shown in FIG. 12A, after preparing a transparent first substrate 510, a first metal material such as Cu, Ti, Cr, Al, Mo, Ta, and Al alloy is deposited thereon, and then patterned thereon. Thus, the gate line 501 and the first and second liquid crystal control electrode lines 511a and 511b are formed. In this case, the first and second liquid crystal control electrode lines 511a and 511b may be formed in a process of forming a data line, and the first liquid crystal control electrode line 511a may have a narrow area at a predetermined interval. It is formed to have. That is, the first liquid crystal control electrode lines 511a are formed to have different widths.
Subsequently, SiNx or SiOx is deposited on the entire surface of the substrate including the gate line 501 and the first and second liquid crystal control electrode lines 511a and 511b by a plasma CVD method to form a gate insulating film (not shown). In addition, the semiconductor layer 505 is formed on the gate line 501 by stacking and patterning amorphous silicon and n + amorphous silicon on the gate insulating layer (not shown).
Then, as shown in Figure 12b, after depositing a second metal material such as Cu, Mo, Ta, Al, Cr, Ti, Al alloy on the semiconductor layer 505 and the gate insulating film (not shown) It is patterned so as to cross the gate line 501, and the source line and the drain electrode spaced apart from each other on the data line 503 and the semiconductor layer 505 defining a pixel together with the gate line 501. 502a and 502b are formed, respectively. In this case, when the first and second liquid crystal control electrode lines 511a and 511b are not formed in the gate line 501 forming process, the first and second liquid crystal control electrode lines 511a and 511 in the data line 503 process are not formed. 511b) may be formed together.
Subsequently, an inorganic material such as SiNx or SiOx or an organic material such as benzocyclobutene or acryl is coated on the substrate on which the thin film transistor 509 is formed, and then a protective film (not shown) is applied to the drain electrode 502b. A drain contact hole 507 is formed to expose a portion of the drain contact hole 507.
A transparent conductive film such as indium tin oxide (ITO) or indium zinc oxide (IZO) is deposited on the passivation layer, and then patterned to form a pixel electrode 513, and the first and second liquid crystal control electrodes. Together with lines 511a and 511b, a plurality of first and second slits 514a and 514b are formed to distort an electric field to form a plurality of domains. In this case, the first slit 514a is shaped like an ellipse hole, and a plurality of first slits 514a are continuously disposed along the extending direction of the data line 503.
The plurality of first slits 514a are formed to be continuously arranged at regular intervals, and the separation area between the first slits 514a is positioned in a relatively narrow area of the first liquid crystal control electrode line 511a. Do it.
Finally, although not shown in the drawing, after preparing a second substrate on which a black matrix, a color filter, and a common electrode are formed, the first substrate and the second substrate are bonded together, and a liquid crystal layer is formed therebetween, thereby providing a liquid crystal display. Complete the panel of devices.

As described above, the present invention forms a liquid crystal control electrode to form a normal multi-domain, constitutes an elliptical slit continuously arranged at a predetermined distance, and forms the formation area of the liquid crystal control electrode corresponding to the separation distance between the slits. By reducing, the light transmittance is improved.

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As described above, the present invention prevents deterioration of viewing angle characteristics due to misalignment of the second substrate and the first substrate by forming the slit and the liquid crystal control electrode line, which are means for distorting the electric field only on the first substrate. By forming a multi-domain, by implementing a wide viewing angle, there is an effect that can further improve the display quality.

In addition, the present invention can improve the light transmittance by changing the shape of the liquid crystal control electrode line to minimize the decrease in the aperture ratio.

Claims (20)

A liquid crystal display device comprising a first substrate, a second substrate facing the first substrate, and a liquid crystal layer positioned between the first substrate and the second substrate. Gate lines and data lines formed on the first substrate so as to cross each other to define a plurality of pixel regions; A liquid crystal control electrode line formed in the pixel region and having one region having a different width; A first slit formed in the pixel region to cover the liquid crystal control electrode line, the first slit formed to partially overlap with the liquid crystal control electrode line formed to have a different width, and a second slit formed so as not to overlap the liquid crystal control electrode line It includes a pixel electrode formed, And a plurality of first slits, the liquid crystal display elements being arranged to be spaced apart from each other at regular intervals so as to correspond to a region where widths of the liquid crystal control electrode lines are formed to have different widths. The method of claim 1, The liquid crystal display electrode line includes a second liquid crystal control electrode line formed along an edge of the pixel region, and a first liquid crystal control electrode line provided inside the second liquid crystal control electrode line. . The method of claim 2, The first liquid crystal control electrode line is provided to have a different width, An extended portion of the first liquid crystal control electrode line is provided to correspond to the first slit, and a narrowed portion of the first liquid crystal control electrode line is provided to correspond to an area between the first slits. A liquid crystal display device characterized by the above-mentioned. The method of claim 1, And the liquid crystal control electrode line is formed of the same material as the gate line. The method of claim 1, And the liquid crystal control electrode line is formed of the same material as the data line. The method of claim 2, The first slit is formed along the first liquid crystal control electrode line to partially overlap the first liquid crystal control electrode line. And the second slit is located in an area between the first liquid crystal control electrode line and the second liquid crystal control electrode line. The method of claim 2, The first slit has a vertical length larger than the horizontal length, And the first slit is arranged so that the longitudinal length of the first slit is parallel to the array direction of the plurality of first slits. The method of claim 7, wherein And the plurality of first slits are formed such that a distance between the first slits is smaller than a longitudinal length of the first slits. The method of claim 7, wherein And the plurality of first slits are formed such that a distance between the first slits is smaller than or substantially equal to a horizontal length of the first slits. The method of claim 1, And the liquid crystal control electrode line and the first and second slits have a curved structure. delete The method of claim 1, And a connection pattern for interconnecting the liquid crystal control electrode lines formed in the pixel areas. The method of claim 1, When the pixel voltage applied to the pixel electrode is a negative voltage V _{p (−)} , the voltage applied to the liquid crystal control electrode line is a minimum field distortion voltage lower than the negative pixel voltage V _{p (−)} . When V _min is applied and the pixel voltage applied to the pixel electrode is the bipolar voltage V _{p (+)} , the voltage applied to the liquid crystal control electrode line is higher than the bipolar pixel voltage V _{p (+)} . A maximum electric field distortion voltage (V _max ) is applied to the liquid crystal display device. In the manufacturing method of a liquid crystal display device comprising a first substrate, a second substrate facing the first substrate and a liquid crystal layer positioned between the first substrate and the second substrate, Forming a liquid crystal control electrode line on the first substrate such that one region has a different width; Forming a transparent conductive film to cover the liquid crystal control electrode line; Patterning the transparent conductive layer to form a pixel electrode having a first slit formed to partially overlap with the liquid crystal control electrode line formed to have a different width and a second slit formed so as not to overlap the liquid crystal control electrode line; , The plurality of first slits may be formed to be continuously spaced apart from each other at regular intervals so as to correspond to a region where the width of the liquid crystal control electrode lines are formed to have a different width. Manufacturing method. The method of claim 14, Forming a gate line on the first substrate; Forming a data line on the gate line so as to intersect the gate line to define a plurality of pixel regions; And the liquid crystal control electrode line is formed at the same time as the gate line. The method of claim 14, Forming a gate line on the first substrate; Forming a data line on the gate line so as to intersect the gate line to define a plurality of pixel regions; And the liquid crystal control electrode line is formed at the same time as the data line. The method according to claim 15 or 16, The liquid crystal control electrode line includes a second liquid crystal control electrode line formed along an edge of the pixel region, and a first liquid crystal control electrode line provided inside the second liquid crystal control electrode line. And the first liquid crystal control electrode lines are provided to have different widths. The method of claim 17, The liquid crystal control electrode line is provided such that an extended portion of the first liquid crystal control electrode line corresponds to the first slit, and a portion of the first liquid crystal control electrode line that has narrowed width is an area between the first slits. The manufacturing method of the liquid crystal display element characterized by the above-mentioned. delete delete

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