KR100828511B1 - Rubbing cloth and method for manufacturing liquid crystal display device using the same - Google Patents

Abstract

A rubbing cloth for use in a rubbing process for forming an alignment groove of a liquid crystal display device is disclosed. The rubbing cloth extends from one side of the rubbing cloth fabric and the rubbing cloth fabric formed by crossing a plurality of warp yarns and a plurality of weft yarns having a shorter length than the warp yarns, and having a density of 28,500 to 35,000 pieces per square centimeter. It includes a plurality of rubbing files consisting of. By rearranging the direction of the rubbing pile in parallel with the weft, the rubbing pile is uniformly distributed. Therefore, rubbing defects generated during the rubbing process can be prevented. In addition, when using a rubbing cloth having a density of the filament, the rubbing intensity is increased, which has the effect of improving the optical characteristics of the liquid crystal display device.

Description

Rubbing cloth and method for manufacturing liquid crystal display device using the same}

1 is a perspective view of a rubbing cloth fabric for producing a conventional rubbing cloth.

FIG. 2 is a perspective view illustrating an irregular rubbing fiber formed on the rubbing cloth fabric shown in FIG. 1.

3 is an enlarged view of a portion A of FIG. 2.

4 is a perspective view illustrating an alignment process of the rubbing pile illustrated in FIG. 2.

5 is a perspective view illustrating a process of drying a rubbing cloth from the rubbing cloth fabric shown in FIG. 4.

FIG. 6 is a schematic diagram illustrating a rubbing process by the rubbing cloth shown in FIG. 5.

Figure 7 is a perspective view showing a rubbing cloth fabric with a rubbing pile according to an embodiment of the present invention.

FIG. 8 is a detailed view for explaining the rubbing file illustrated in FIG. 7.

9 is a perspective view illustrating an alignment process of the rubbing pile illustrated in FIG. 7.

10 is a perspective view illustrating a process of drying a rubbing cloth from the rubbing cloth fabric shown in FIG. 9.                 

FIG. 11 is a schematic diagram illustrating a rubbing process by the rubbing cloth shown in FIG. 10.

Explanation of symbols on the main parts of the drawings

1: weft 2: warp

100, 600: Loving cloth fabric 110, 115, 118: Loving file

112: rubbing filament 150, 800: rubbing cloth

300: rubbing roller

The present invention relates to a rubbing cloth used in the manufacture of a liquid crystal display device. More particularly, the present invention relates to a rubbing cloth for forming an alignment groove for aligning a liquid crystal on a glass substrate of a liquid crystal display device.

Recently, as the modern society becomes information society, the importance of the liquid crystal display device, which is one of the information display devices, is gradually increasing. In particular, due to advantages such as miniaturization, light weight, and low power consumption of LCDs, LCDs are increasingly being used as an alternative means to overcome disadvantages of cathode ray tubes (CRTs). .

In general, such a liquid crystal display device has a structure in which liquid crystal molecules are injected between two glass substrates. In this case, the liquid crystal molecules injected between the organic substrates are changed in accordance with an electrical signal applied from the outside. It serves to ensure that the light transmittance of the device is adjusted to an appropriate amount.

In this case, in order for the liquid crystal display device to exhibit a particular optical effect, it is necessary to align the liquid crystal molecules in a specific direction. Since the normal liquid crystal molecules are only locally aligned, the liquid crystal molecules may be aligned in a specific direction. Organic polymer films in direct contact with the molecules are artificially formed on the ITO electrode. Such an organic polymer film is usually referred to as an alignment film.

A rubbing process is a process of forming an alignment groove on the surface of the alignment film. A rubbing cloth made of rayon, nylon, or the like is wound on a roller, and then the roller is placed on the alignment film. By contacting and rubbing with the surface of the alignment layer, the alignment layer is a process of forming a series of alignment grooves having a uni-directional alignment and a range of pretilt angles.

One example of such a rubbing process is US Pat. No. 4,634,228 issued to Iwasaki, et al. 5,400,159 (issued to Takao, et al.) “Liquid crystal device having alignment film with particular surface energy difference before and after rubbing”, United States Patent No. 5,710,610 (issued to Kim) “Apparatus and method for creating multiple tilt angles by rubbing the alignment layer on the alignment layer applied to the thin film transistor by rubbing and the color filter glass substrate of the liquid crystal display. applied tothin film transistors and color filter glass plate of a liquid crystal display) ”, US Patent No. 5,744,203 Issued to Harada, et al., “Alignment layer for liquid crystal” and the like.

The alignment layer is coated with an alignment layer raw material solution made of polyamic acid, soluble polyimide, or the like on a substrate, followed by a pre-curing step of about 60 ° C. to 80 ° C., and a main curing of about 180 ° C. to 200 ° C. By carrying out the main-curing) process, it forms by polyimidating the said polyamic acid and soluble polyimide. Then, by performing the rubbing process on the polyimide-oriented alignment film, a series of alignment grooves are formed on the surface of the alignment film.

In general, the rubbing device for forming the alignment grooves includes a rubbing roller on which a rubbing cloth is wound and a stage on which the substrate is placed. The stage is formed with a plurality of vacuum holes provided with a vacuum for adsorbing the substrate, and is provided with a plurality of lift pins for loading or unloading the substrate onto the stage. When the substrate is loaded into the stage, the rubbing roller rotates and moves to rub against the upper surface of the substrate, and the alignment groove is formed on the alignment film of the substrate to be rubbed with the rubbing roller.

The most basic in setting the conditions of the rubbing process is to set the appropriate rubbing strength and to make the rubbing strength (RS) uniform over a large area.

If the rubbing is not uniform, the alignment of the liquid crystal molecules is not spatially constant, resulting in uniformity (Uniformity) defects that show locally different optical properties.

The process variable of the rubbing is determined by the number of rubbing, the rubbing depth, the rotation speed of the roller, the moving speed of the radial stage of the roller, and the like. However, the process variables are not easily changed because they are related to the process conditions of each company. However, in addition to the above process variables, the length, strength, thickness, density, and the like of the rubbing cloth also become important factors of the rubbing process.

On the other hand, in the conventional liquid crystal display device, the electrodes are provided on each of the upper and lower substrates on which the liquid crystal is placed, the electrodes are arranged so that the electric field applied to the liquid crystal is perpendicular to the substrate surface, and the display is performed using the opticality of the liquid crystal layer. The nematic (twisted nematic) method is typically used. However, the liquid crystal display device using the TN method is the biggest problem that the viewing angle is narrow.

In recent years, an in-plane switching (IPS) method in which a liquid crystal is operated by using a comb-shaped electrode so that the generated electric field has a component parallel to the substrate surface, and displays using the birefringence of the liquid crystal. This is disclosed in Japanese Patent Laid-Open No. 6-22739. Since the IPS method is due to in-plane switching of liquid crystal molecules, the viewing angle is wider than that of the TN method, and there is an advantage such as a low load capacity. Thus, the IPS method is a new active-driven liquid crystal display device that replaces the TN method. The optical characteristics of the IPS type liquid crystal display device are greatly influenced by the rubbing intensity, which is a main variable of the rubbing process, compared to the TN type.

Accordingly, attempts have been made to improve the characteristics of the rubbing cloth in order to improve the optical characteristics of the liquid crystal display device. For example, Korean Patent Publication No. 2001-28555 discloses a method for manufacturing a rubbing cloth for a liquid crystal display device. Rubbing cloth prepared by the method ”is disclosed.

Hereinafter, a process of manufacturing a rubbing cloth will be described with reference to the accompanying drawings.

First, the rubbing cloth fabric 100 used repeatedly refers to a cloth having a narrow width and a long length, as shown in FIG. 1. The rubbing cloth fabric 100 is manufactured by intersecting a warp yarn 2 having a very long length and a weft yarn 1 having a very short length compared to the warp yarn 2. Thus, in the rubbing cloth fabric 100 composed of the warp yarns 2 and the weft yarns 1, a rubbing pile 110 extending to one side of the rubbing cloth fabric is formed without direction as shown in FIGS. 2 and 3. do. The rubbing pile is a bundle of rubbing filments with a fine diameter and has a very short length. The rubbing pile 110 serves to form an alignment groove in the alignment layer by rubbing with the alignment layer. For this purpose, the rubbing pile should be aligned in the same direction as the desired alignment groove.

Figure 4 shows a process for imparting a direction to the rubbing pile formed without a direction on the rubbing cloth fabric. Referring to FIG. 4, the roller brush 200 rearranging the rubbing pile 110 is positioned to be parallel to the width direction of the rubbing cloth fabric 100. That is, the roller brush 200 is transported in contact with the roller brush 200 in a state in which the rubbing cloth fabric 100 is arranged in parallel with the weft yarn 1 of the rubbing cloth fabric 100 or the roller brush 200 is transported. While the rubbing pile 110 formed in the rubbing cloth fabric 100 is rearranged in a direction parallel to the warp yarn (2). The rearranged rubbing files are assigned with reference numeral 115 to distinguish them from the rubbing files 110 before being rearranged.

Thereafter, as shown in FIGS. 5 and 6, the rubbing cloth fabric 100 is dried in a state in which the rubbing piles 110 are rearranged in the rubbing cloth fabric 100. Hereinafter, the dried rubbing cloth fabric 100 will be defined as a rubbing cloth 150. The dried rubbing cloth 150 is attached to the rubbing roller 300 having a length at least longer than the width of the alignment layer. In this way, in order for the rubbing cloth 150 to be attached to the rubbing roller 300, the length of the rubbing cloth 150 is equal to the length of the rubbing roller 300, and the longitudinal length thereof is the circumferential surface length of the rubbing roller 300. Dried to be equal to. That is, the warp yarn 2 of the rubbing cloth 150 has a direction surrounding the circumferential surface of the rubbing roller 300, the weft yarn 1 faces the longitudinal direction of the rubbing roller 300, and the rubbing pile 110 is a warp yarn. Aligned in parallel with (2).

Thereafter, the rubbing roller 300 wound around the rubbing cloth 150 is pressed to a predetermined pressure on the upper surface of the alignment layer 400 and then rotated to form a culture groove. However, as shown in FIG. 6, when the culture groove is formed in the alignment layer 400 in a state in which the conventional rubbing cloth 150 is attached to the rubbing roller 300, unwanted vertical streaks 410 on the alignment layer 400 are formed. There is a problem that is formed.

This problem is because it is wound around the rubbing roller 300 in the direction of the warp yarn 2 having a very long length. That is, when manufacturing the rubbing cloth 150, since the overall tension is difficult to adjust in the warp direction of the rubbing cloth fabric 100, the tension is not constant throughout the rubbing cloth fabric 100, and thus, the rubbing cloth ( The distribution of the rubbing pile 110 of 150 is made non-uniform.

Accordingly, a first object of the present invention is to provide a rubbing cloth that can increase the rubbing strength while forming a uniform alignment groove.

A second object of the present invention is to provide a method of manufacturing a liquid crystal display device using the rubbing cloth to improve optical characteristics.

A rubbing cloth according to the present invention for achieving the first object is a rubbing cloth fabric formed by crossing a plurality of warp yarns and a plurality of weft yarns having a length shorter than the warp yarns; And

And a plurality of rubbing piles extending from one side of the rubbing cloth fabric and comprising a plurality of rubbing filaments having a density of 28,500 to 35,000 per cm 2.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, including: a) a thin film transistor, a power supply line for driving the thin film transistor, and a pixel electrode to which the power output from the thin film transistor is applied. Step of manufacturing a TFT substrate

b) fabricating a color filter substrate coupled with the TFT substrate and having an RGB pixel and a common electrode formed thereon;

c) extending from one side of the rubbing cloth fabric and the rubbing cloth fabric formed by crossing a plurality of warp yarns and a plurality of weft yarns having a length shorter than the warp yarns on top surfaces of the alignment film formed on the TFT substrate and the color filter substrate; Rubbing a rubbing roller wound around a rubbing cloth comprising a plurality of rubbing piles comprising rubbing filaments having a density of 28,500 to 35,000 per square centimeter to form an orientation groove;

d) assembling the TFT substrate and the color filter substrate; And

e) injecting a liquid crystal between the TFT substrate and the color filter substrate.

As an example, the liquid crystal display device manufactured as described above uses an IPS method in which the liquid crystal is arranged in a direction parallel to the TFT substrate and the color filter substrate when power is applied.

Accordingly, the rubbing pile formed on the rubbing cloth formed by orthogonal weft yarns having a shorter length than the warp yarns having a longer length can be rearranged in parallel with the weft yarns, thereby preventing rubbing defects generated during the rubbing process, and the alignment film. Irrespective of the length of the rubbing cloth can be produced in various sizes.

In addition, by increasing the density of the rubbing filament constituting the rubbing pile, the rubbing intensity is increased, which has the effect of improving the optical characteristics of the liquid crystal display.

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

FIG. 7 is a schematic diagram illustrating a method of manufacturing a rubbing cloth according to an embodiment of the present invention, and FIG. 8 is a view illustrating a rubbing file shown in FIG. 7.

Referring to FIGS. 7 and 8, the rubbing cloth is composed of a rubbing cloth 110 formed on one side of the rubbing cloth fabric 600 and the rubbing cloth fabric 600 as a whole. Specifically, the rubbing cloth fabric 600 is a warp yarn 2, a warp yarn 2 orthogonal to the warp yarns 2 are interwoven alternately woven fabric warp 2 is longer than the weft yarn (1). The rubbing pile 110 is a bundle of fine rubbing filaments 112 and extends to one side of the rubbing cloth fabric 600. The rubbing pile 600 has a certain direction by a brush or the like, the direction of the rubbing pile 110 is rearranged in the weft (1) direction of the rubbing cloth fabric (600). At this time, the angle between the rubbing pile 110 and the weaving cloth 1 of the rubbing cloth fabric 600 is preferably within ± 30 ° based on the weft yarn 1. At this time, it is most preferable that the weft yarn 1 and the rubbing pile 110 are parallel to each other. The material of the rubbing filament 112 constituting the rubbing pile 110 is rayon, the diameter is 2.4 to 2.6D (denier), the total thickness of the rubbing cloth is 1.7 to 1.9mm. In the embodiment of the present invention, the diameter of the rubbing filament 112 was formed to 2.5D, and the overall thickness of the rubbing cloth was formed to be 1.8 mm. At this time, the density of the rubbing filament 112 is 28,500 to 35,000 pieces per 1 cm 2, in the embodiment of the present invention to form 32,000 rubbing filaments 112 per cm 2. Here, the diameter of the rubbing pile 110 is 100D, and the density of the rubbing pile 110 is proportional to the density of the rubbing filament 112.

Forming the rubbing pile 110 in parallel with the short weft 1 as compared to the warp yarn 2, when the rubbing pile 110 is formed in parallel with the long warp yarn 2, tension adjustment is constant. This is because the gap between the rubbing piles 110 is not uniform, so that a rubbing process defect occurs frequently. On the contrary, when the rubbing pile 110 is formed in parallel with the weft yarn 1, which is shorter than the warp yarn 2, tension adjustment can be made constant, thereby preventing uneven spacing of the rubbing pile 110. It has the advantage to do it.

Hereinafter, after describing the process of manufacturing the rubbing cloth, a process of proceeding the rubbing process with the rubbing cloth will be described.

Referring to FIG. 7, a rubbing pile 110 having a predetermined length is formed on a rubbing cloth fabric 600 woven by crossing a very long warp yarn 2 and a short weft yarn 1. At this time, the rubbing pile 110 is formed on the rubbing cloth fabric 600 without direction. As described above, the direction of the warp yarn 2 of the rubbing cloth fabric 600 in which the rubbing pile 110 is formed is defined as the length direction of the rubbing cloth fabric 600, and the direction of the weft yarn 1 of the rubbing cloth fabric 600 is defined. It will be defined as the width direction of the rubbing cloth fabric (600).

Thereafter, as shown in FIG. 9, the rubbing pile 110 in which the rubbing cloth fabric 600 is formed is rearranged by the rubbing belt 710. Hereinafter, reference numeral 118 will be given to the rearranged rubbing file. At this time, the rubbing belt 710 is provided in the width direction of the rubbing cloth fabric (600). Specifically, a rubbing belt 710 is provided to rearrange the direction of the rubbing pile 110 in a direction forming an angle within ± 30 ° with the weft yarn 1 based on the weft yarn 1, and the rubbing belt 710 is provided. Two pulleys 720 and 730 for driving and a driving device 740 for rotating one of the pulleys 720 and 730 are provided.                     

Thereafter, as shown in FIG. 10, the rubbing cloth fabric 600 in which the rubbing pile 118 is rearranged is dried in the longitudinal direction of the rubbing cloth fabric 600 to produce a rubbing cloth 800. Specifically, the rubbing cloth 800 is dried so as to be completely wound on the rubbing roller 300 as shown in FIG. 11. That is, the rubbing cloth 800 has a width comparable with the length of the circumferential surface of the rubbing roller 300 and a length comparable with the length of the rubbing roller 300. At this time, the width of the rubbing cloth fabric (600) defined in advance in the width direction of the circumferential surface of the rubbing roller (300) to be parallel, and the rubbing roller (300) in the longitudinal direction of the rubbing cloth fabric (600) defined above The rubbing cloth 800 is made to be equal to the length of the rubbing cloth.

When the rubbing cloth 800 is manufactured in this manner, as shown in FIG. 11, the scratches of the rubbing pile 115 of the rubbing cloth 800 are uneven in the course of performing the rubbing process on the alignment layer 400. It does not occur.

In addition, when the size of the alignment layer 400 is increased, specifically, the rubbing cloth 800 suitable for the size of the alignment layer 400 even if the size of the alignment layer 400 is larger than the width of the rubbing cloth fabric 600 as shown by reference numeral 500. ) Can be obtained. This is realized by adjusting only the lengthwise longitudinal length of the rubbing cloth fabric 600.

Hereinafter, a process of manufacturing a liquid crystal display using a rubbing cloth according to an embodiment of the present invention will be described.

First, a thin film transistor, a gate line, a data line, and even a pixel electrode are formed on a TFT substrate of a liquid crystal display device, and a flat polyimide film is formed on an upper surface of the TFT substrate. Then, a rubbing process for forming an alignment groove for aligning the liquid crystal on the polyimide film is performed. At this time, the rubbing process is performed by a rubbing roller, a rubbing cloth is attached to the rubbing roller.

A rubbing cloth wound on a rubbing roller is a woven fabric made by crossing a very long warp yarn and a short weft, and a rubbing pile is arranged in a direction parallel to the weft yarn. The rubbing pile rubs with the polyimide film to form grooves in which the liquid crystal is arranged in the rubbing pile direction.

This process is repeated for the color filter substrate. At this time, the liquid crystal alignment grooves formed in the color filter substrate are tilted at a predetermined angle with the liquid crystal alignment grooves formed in the TFT substrate to enable the liquid crystal display according to the alignment of the liquid crystals.

Thereafter, the liquid crystal is injected between the color filter substrate and the TFT substrate in the aligned state of the color filter substrate and the TFT substrate to fabricate the liquid crystal display panel, and then other components are assembled to the liquid crystal display panel to fabricate the liquid crystal display device.

The rubbing intensity which is the most basic condition of the rubbing process can be obtained simply by the following equation.

Here, the variables of the equation are as follows.

However, the above formula does not take into account the parameters of the rubbing cloth, and when using a rubbing cloth such as an embodiment of the present invention, the rubbing intensity increases according to the density of the rubbing filament, which is an optical characteristic of the liquid crystal display device. The afterimage, the reaction rate of the liquid crystal, the contrast rate and the like are improved. Such optical characteristics are more remarkable in the IPS type liquid crystal display device than the TN type liquid crystal display device, which is related to the driving direction of the liquid crystal. That is, in the case of the TN method, the arrangement of the liquid crystal is changed in the vertical direction when an electric field is applied, whereas in the case of the IPS method, the direction of the liquid crystal is changed in a direction horizontal to the substrate when the electric field is applied.

In order to confirm the degree of improvement of the optical characteristics, the liquid crystal display of the IPS method was manufactured using the rubbing cloth according to the embodiment, and the optical characteristics of the liquid crystal display and the conventional characteristics were compared.

Table 1 shows the specifications of the conventional rubbing cloth according to an embodiment of the present invention.

Item Comparative Example 1 Comparative Example 2 Example material Rayon Rayon Rayon Pile diameter 100 D 120 D 100 D Filament diameter 2.5 D 3 D 2.5 D Filament density 28,000 24,000 32,000 Full thickness 1.8mm 1.8mm 1.8mm Cutting method Longitudinal direction Longitudinal direction Transverse

In Table 1, the cutting method means a direction in which the rubbing cloth is dried from the rubbing cloth fabric.

Table 2 shows the evaluation results of the optical characteristics of the liquid crystal display manufactured using the rubbing cloth.

 Evaluation item  Evaluation results  Rising time  Improving  Luminance Specification Example evaluation Conventional White 170MIN / 200MAX 248.52 Improving 240.6 black - 0.58 Improving 0.57 Contrast ratio 350TYP 429.58 Improving 422 Uniformity 25% MAX 22.39% Improving 16.1%       Color reproducibility Chromaticity (center) Example evaluation Conventional  White X 0.293-0.343 0.31     Same (good) 0.309 Y 0.314-0.364 0.33 0.325 WL - 230.1 Red X 0.609 ~ 0.659 0.63 0.632 Y 0.329-0.379 0.35 0.351 RL - 56.02  Green X 0.297-0.329 0.3 0.298 Y 0.556-0.606 0.57 0.574 GL - 149.3  blue X 0.118-0.168 0.14 0.143 Y 0.077-0.127 0.09 0.093 BL - 26.28  Color reproducibility  62.17%  Improving  61.57%  afterimage  Up to 2x improvement   responsibility  High temperature operating life test-dynamic (50 ° C., 250 hr), high temperature operating life test-white (50 ° C., 250 hr); Good evaluation result

In Table 2, it can be seen that when the rubbing cloth according to the embodiment of the present invention is used, the optical characteristics of the liquid crystal display are improved.

Referring to Table 2, the rising time is for measuring the response time of the liquid crystal. The maximum luminance is obtained when voltage is applied to the liquid crystal and the long axes of the liquid crystal are arranged in the same direction as the electric field to reach a metastable state. If it is optimized to 100, it is the time it takes for the brightness to change from 90% to 10%.

In addition, it can be seen that the brightness is improved, and that the contrast rate is improved. Contrast ratio is a measure of how clearly an image looks on the screen. The contrast ratio is defined as a value obtained by dividing the white luminance value by the black luminance at the front center of the liquid crystal display. Therefore, the improved contrast ratio means that the resolution of the liquid crystal display device is improved.

In addition, color reproducibility was improved, and the time for which an afterimage remained was reduced. In order to evaluate the reliability of the liquid crystal display, a high temperature operating life (HTOL) test was performed. The HTOL test was conducted at 50 ° C. for 250 hours in a state where the screen pattern was continuously changed and fixed to a white screen, and the evaluation result was good.

According to the present invention as described above, by rubbing the direction of the rubbing pile formed on the rubbing cloth formed by orthogonal weft shorter than the long warp and warp in parallel with the weft so that the rubbing pile is evenly distributed, rubbing It is possible to prevent rubbing defects generated during the process and also to produce a rubbing cloth of various sizes regardless of the length of the alignment layer.

In addition, by increasing the density of the rubbing filament constituting the rubbing pile, the rubbing intensity is increased, which has the effect of improving the optical characteristics of the liquid crystal display.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (5)

In a rubbing cloth wound on a rubbing roller, A rubbing cloth fabric formed by crossing a plurality of warp yarns and a plurality of weft yarns having a shorter length than the warp yarns; And A plurality of rubbing piles extending from one side of the rubbing cloth fabric and comprising a plurality of rubbing filaments having a density of 28,500 to 35,000 per square centimeter, And a rubbing cloth in the width direction of the rubbing cloth so as to correspond to the length of the circumferential surface of the rubbing roller, and rubbing so as to correspond to the length of the rubbing roller in the longitudinal direction of the rubbing cloth. The rubbing cloth of claim 1, wherein the rubbing piles are aligned to have an angle of −30 to + 30 ° with respect to the weft yarn. a) manufacturing a TFT substrate having a thin film transistor (TFT), a power supply line for driving the thin film transistor, and a pixel electrode to which the power output from the thin film transistor is applied; b) manufacturing a color filter substrate coupled with the TFT substrate and having an RGB pixel and a common electrode formed thereon; c) extending from one side of the rubbing cloth fabric and the rubbing cloth fabric formed by crossing a plurality of warp yarns and a plurality of weft yarns having a length shorter than the warp yarns on top surfaces of the alignment film formed on the TFT substrate and the color filter substrate; Rubbing a rubbing roller wound around a rubbing cloth comprising a plurality of rubbing piles comprising rubbing filaments having a density of 28,500 to 35,000 per square centimeter to form an orientation groove; Assembling the TFT substrate and the color filter substrate; And Injecting a liquid crystal between the TFT substrate and the color filter substrate, The rubbing cloth may be dried to correspond to the length of the circumferential surface of the rubbing roller in the width direction of the rubbing cloth fabric, and to be dried to correspond to the length of the rubbing roller in the longitudinal direction of the rubbing cloth fabric. Method of manufacturing the device. The liquid crystal display of claim 3, wherein an in-plane switching (IPS) method is used in which the liquid crystal is arranged in a direction parallel to the TFT substrate and the color filter substrate when power is applied. Method of preparation. The method of claim 3, wherein the rubbing piles are aligned to have an angle of −30 ° to + 30 ° with respect to the weft yarn.

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