KR101421167B1 - Liquid crystal display device and fabricating method thereof - Google Patents

Abstract

The present invention provides a liquid crystal display device comprising a polyimide-based first alignment layer and a second alignment layer that is bonded to the first alignment layer, wherein the second alignment layer has a soft- A first substrate on which a thin film transistor is formed, and a second substrate on which a thin film transistor is formed; A second substrate bonded to the first substrate and opposite to the first substrate, the second substrate having a black matrix and a color filter; A first alignment layer formed on at least one of the first substrate and the second substrate and having a functional group of methyl (-CH ₃ ); A second alignment layer formed on the first alignment layer, the second alignment layer being bonded to the methyl to form a microgroove so as to have a predetermined angle of view; And a liquid crystal layer formed by injecting liquid crystal between the first substrate and the second substrate.

Alignment films, microgrooves, imprinting,

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal display device and a method of manufacturing the same,

More particularly, the present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device and a method of manufacturing the same, The first alignment layer and / or the second alignment layer may have a microgroove formation and orientation through imprinting by an electrical force between the metal layer (or electrode) on the soft mold and the electrode on the substrate on which the second alignment layer is formed, And a method of manufacturing the same.

2. Description of the Related Art In general, liquid crystal display devices are composed of a thin film transistor array substrate, a color filter substrate, and a liquid crystal interposed between the two substrates. Particularly, as a process before the adhesion, the thin film transistor array substrate and the color filter substrate undergo a common alignment film printing and rubbing process.

At this time, the alignment film printing and the rubbing process have been considered more important than others for the following reasons. That is, it is difficult to obtain a uniform molecular arrangement state of the liquid crystal simply by interposing the liquid crystal between the two substrates. Therefore, it is required to form an alignment film for uniform orientation in the wall of the substrate.

In addition, since the physical property constants of the liquid crystal vary depending on the molecular arrangement state, and as a result, the response to an external force such as an electric field varies greatly, uniform alignment control of the liquid crystal is a key point in manufacturing a liquid crystal display element .

The orientation film formation and rubbing process will now be described with reference to the drawings.

1A is a view showing a process of forming an alignment film using a roller printing method.

As shown in FIG. 1A, the general orientation film formation uses a printing method using a plurality of rollers. That is, the alignment liquid 10 supplied between the cylindrical annealing roll 22 and the doctor roll 23 is rotated by the annealing roll 22 and the doctor roll 23 so that the entire annealing roll 22 Lt; / RTI > At this time, the alignment liquid 10 is supplied by the dispenser 1 in the form of a syringe.

The annealing roll 22 is brought into contact with a printing roll 24 having a rubber plate 25 attached thereto in a predetermined region of the surface thereof and rotated so that the alignment solution 10 on the surface of the annealing roll 22 is pressed against the rubber plate 25, Lt; / RTI > The rubber plate 25 corresponds to the substrate 26 to which the alignment liquid 10 is to be applied and a master pattern is formed on the substrate 26 so as to selectively print an alignment film.

At this time, as the printing table 27 on which the substrate 26 is mounted moves in contact with the printing roll 24, the alignment liquid 10 transferred to the rubber plate 25 is re-transferred onto the substrate 26, .

Since the thickness of the ordinary alignment film is about 500 to 1000 angstroms and the thickness difference of about 100 angstroms on the same substrate may cause defects such as unevenness due to uneven orientation on the screen of the liquid crystal display element, Is an important factor that influences.

Next, in the substrates having the alignment film formed thereon, the alignment films are rubbed so that the liquid crystal molecules are arranged in a predetermined direction, thereby forming the bones in a certain direction.

1B is a perspective view schematically showing a general rubbing process.

The rubbing process is performed by winding the rubbing cloth 35 on the roller 30 and using the rubbing cloth 35 as the alignment film 21, In a certain direction.

When the surface of the alignment film 21 is rubbed, the surface of the alignment film 21 has a shape having a fine groove 36.

The rubbing cloth 35 uses a soft fiber cloth, and the rubbing equipment including the roller 30 is relatively simple. The most basic reason for setting the rubbing process conditions is to set rubbing conditions of appropriate intensity and to make the rubbing intensity uniform over a large area.

In recent years, as the size of the glass substrate becomes larger, the pressure distribution of the rubbing is changed in all regions, so that uniform rubbing can not be performed. As a result, different alignment states are shown for each region.

As a result, the degree of alignment of the liquid crystal molecules is not spatially constant and locally different optical characteristics are exhibited, causing uneven brightness.

In addition, the life of the rubbing cloth used for rubbing is about 5,000 sheets, and the amount of the rubbing cloth used is also increased, resulting in an increase in cost.

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the problems described above, and its object is to provide a method of manufacturing a liquid crystal display device, which is capable of uniformly forming an alignment film on a glass substrate, particularly a large-area glass substrate, The microgrooves formed on the alignment film and the chain alignment formed at the same time as the formation of the microgrooves are formed by a metal layer (or electrode) on the soft mold and a second alignment film And a method of manufacturing the liquid crystal display element by imprinting using an electric force applied between the electrodes on the substrate on which the liquid crystal display panel is formed.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a first substrate on which a thin film transistor is formed; A second substrate bonded to the first substrate and opposite to the first substrate, the second substrate having a black matrix and a color filter; A first alignment layer formed on at least one of the first substrate and the second substrate and having a functional group of methyl (-CH ₃ ); A second alignment layer formed on the first alignment layer, the second alignment layer being bonded to the methyl to form a microgroove so as to have a predetermined angle of view; And a liquid crystal layer formed by injecting liquid crystal between the first substrate and the second substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, including: providing a first substrate and a second substrate; Forming an electrode on at least one of the first substrate and the second substrate; Forming a polyimide-based first alignment layer on the substrate on which the electrode is formed; Forming a second alignment layer material having a functional group on the first alignment layer; Providing a soft mold in which a relief pattern is formed at regular intervals on a bottom surface and an engraved pattern is formed between the relief patterns and a metal layer is formed on the relief pattern and the relief pattern on a substrate on which the second alignment film material is formed; Applying a voltage between the metal layer of the soft mold and an electrode on the substrate; A soft mold is imprinted on the second alignment film material on the substrate to form a microgroove by an electric field and a second alignment film is formed by orienting the second alignment film material so as to have a predetermined square- ; And forming a liquid crystal layer by laminating the first substrate and the second substrate on which the second alignment layer is formed.

As described above, after a voltage is applied between the metal layer of the soft mold and the electrodes of the first or second substrate on which the first and second alignment films are formed, the soft mold is brought into contact with the alignment film by the voltage, By simultaneously performing the formation and orientation, it is possible to achieve uniform alignment over a large area, and as a result, the luminance non-uniformity of the liquid crystal display element can be improved.

Hereinafter, the configuration and the manufacturing method will be described in more detail with reference to the drawings.

FIG. 2 is a cross-sectional view showing the structure of a liquid crystal display element according to the present invention and the polarity of an alignment film constituting the element, and FIG. 3 is a structural formula showing a bonding structure of the first alignment film and the second alignment film in FIG.

The liquid crystal display device according to the present invention includes a backlight unit disposed at a lower portion of a liquid crystal panel and used as a light source, and a driving unit positioned at an outside of the liquid crystal panel and driving the liquid crystal panel.

2 and 3, the liquid crystal panel includes a first substrate 100, that is, a thin film transistor array substrate, a second substrate 200, that is, a color filter substrate, And a liquid crystal layer 300 formed by interposing a liquid crystal therebetween. In this case, the first substrate 100 and the second substrate 200 are bonded to each other through a common alignment film printing (or coating) process and an imprinting process using a soft mold in which a metal layer is formed on a portion forming an embossing and embossing, A first alignment layer 110 and 210 and a second alignment layer 120a and 220a which are bonded to the first alignment layers 110 and 210 and have microgrooves formed thereon.

Here, the first alignment layers 110 and 210 are formed of a polyimide-based material, and the first alignment layers 110 and 210 are bonded to the R-group of the first alignment layers 110 and 210, that is, methyl (-CH ₃ ) The two orientation layers 120a and 220a may be made of a material such as methyl acrylate or dimethylamino acrylate having a functional group having a strong polarizing action so as to be relatively sensitive to an electric field, Based acrylate.

As described above, the functional groups that are strongly polarized in the methyl acrylate of the second alignment layers 120a and 220a are formed on the metal layer formed on the soft mold and the first substrate 100 or the second substrate 200 The microgrooves are formed according to the intensity of the voltage applied between the electrodes 109 and 209 formed on the second alignment layers 120 and 220. At the same time, the chains of the second alignment layers 120 and 220 have different degrees of reactivity And a pretilt angle determined by viewing.

Although not shown in the drawing, the driving unit is implemented in a printed circuit board (PCB). The PCB is divided into a gate PCB connected to the gate line of the liquid crystal panel and a data PCB connected to the data line. Each of the PCBs is mounted on each of the data pad portions formed on one side of the liquid crystal panel and connected to the data lines formed on the upper side orthogonal to the one side where the gate pad portion is formed, And is connected to a TCP (tape carrier package).

Although not shown in the drawings, a plurality of gate lines and data lines are formed on the first substrate 100 so as to intersect with each other to define unit pixels in a matrix form, and thin films A plurality of gate pads and data pads formed at the ends of the gate lines and / or the data lines, contact holes formed on the gate pads and the data pads, And a pixel electrode 109 formed on a unit pixel of the pixel unit.

At this time, a polyimide-based first alignment layer 110 is formed on the entire surface of the first substrate 100 on which the pixel electrode 109 is formed, and on the first alignment layer 110, A second alignment layer 120a made of methyl acrylate or dimethyl acrylate such as methyl acrylate or dimethyl acrylate having a strong functional group with strong polarizability bonded to the R-group of the first alignment layer 110 is formed.

Of course, microgrooves are formed on the first alignment layer 110 and / or the second alignment layer 120a so that the liquid crystal can be aligned. At this time, the formation of the microgrooves and the orientation of the second alignment layer 120a (+) Voltage applied to the metal layer of the soft mold formed on one side of the embossed and engraved patterns and having the metal layer formed on the embossed and engraved patterns, and the negative (+) voltage applied to the pixel electrodes (Or electric field) between the negative (-) voltage applied to the second alignment layer 120a and the second alignment layer 120a.

In other words, any one of the soft mold or the first substrate 100 moves according to the intensity of the applied voltage within about 20V applied from the outside, and the contact is made according to the intensity of the voltage. At this time, Of the soft mold is slightly and finely lifted at a center portion of the soft mold by a relatively weak voltage to form a microgroove having a height of about 1 to 10 nm. At the same time, the chain or the side chain of the second alignment layer 120a forming the microgrooves is oriented such that the functional group having strong polarization is reacted with the electric field to have a certain directionality.

For example, a voltage of 0.5 V between the metal layer of the soft mold and the pixel electrode 109 of the first substrate 100 may be applied to the pixel electrode 109 of the first substrate 100. In this case, Assuming that about 45% of the alignment is made when the elapse of about 2 minutes after the application of the voltage, the pretilt angle can be adjusted according to the intensity of the voltage and the application time of the voltage.

Here, it is assumed that the soft mold for forming the microgrooves in the unit of nano unit is formed in the range of 1 to 10 mu m in the step between the embossed pattern and the engraved pattern.

Although not shown in the drawing, the second substrate 200 includes a black matrix formed corresponding to the gate lines and the data lines of the first substrate 100 and the TFTs, and a black matrix formed by the black matrix, A color filter that implements red (R), green (G), and blue (B) colors corresponding to the pixel electrodes 109 of the overcoat layer 100 and an overcoat layer formed on the color filter, A common electrode 209 is formed and is opposed to the pixel electrode 109 on the first substrate 100.

At this time, a polyimide-based first alignment layer 210 is formed on the entire surface of the second substrate 200 on which the common electrode 209 is formed, as in the case of the first substrate 100, A second alignment layer 220a made of methyl acrylate such as methyl acrylate or dimethyl acrylate having a strong functional group that is repeatedly repeated on the first alignment layer 210 and has a strong polarizing action bonded to the R-group of the first alignment layer 210 Respectively.

Of course, in order to align the liquid crystal on the first alignment layer 210 and / or the second alignment layer 220a on the second substrate 200, microgrooves are formed. At this time, The orientation of the alignment layer 220a is formed by forming a positive (+) voltage applied to a metal layer of a soft mold formed to have a plurality of positive and negative patterns on one side and having a metal layer formed on the positive and negative patterns, (-) voltage applied to the common electrode 209 formed on the lower portion of the second alignment layer 220a on the second alignment layer 220a.

That is, either the soft mold or the second substrate 200 is moved by a voltage within a range of 0 to 20 V, which is applied from the outside, and a contact is made according to the intensity of the voltage. At this time, a part of the second alignment layer 220a A microgroove having a height of approximately 1 to 10 nm is formed slightly and more precisely on the central portion of the intaglio of the soft mold due to the relatively weak voltage, and a second alignment film (Or side) -chain of the substrate 220a are oriented such that the functional group having a strong polarization is reacted with the electric field to have a certain directionality.

For example, the metal layer of the soft mold and the common electrode 209 of the second substrate 200 may have the same orientation as that of the metal layer of the second substrate 200. In this case, Assuming that a polarization (or orientation) of about 45% is achieved when a voltage of 0.5V is applied and then about 2 minutes have elapsed, the pretilt angle can be adjusted according to the voltage intensity and the voltage application time have.

Here, the soft mold for forming the microgrooves in the unit of nano unit is formed in the range of 1 to 10 mu m in the step between the embossed pattern and the engraved pattern.

The first substrate 100 and the second substrate 200 on which the first alignment layers 110 and 210 and the second alignment layers 120a and 220a are formed may be a conductive seal formed outside the substrate, And are joined to each other through a through-hole.

At this time, a dropping step of dropping the liquid crystal between the two substrates is performed in a portion corresponding to the pixel region of the liquid crystal display element in the inside of the conductive chamber line, and the dropwise liquid crystal is uniformly diffused simultaneously with the adhesion of the two substrates The liquid crystal layer 300 is formed.

Of course, the common electrode 209 on the second substrate 200 can be applied with the common voltage Vcom through the common voltage wiring and the seal pattern formed on the common voltage wiring, G, and B pixel voltages (Vdata) applied to the pixel electrodes 109 on the pixel electrodes (R, G, and B).

The formation process of the alignment layer formed on the first substrate 100 and / or the second substrate 200 will be described in more detail with reference to FIGS. 4A and 4B and FIG.

FIGS. 4A and 4B are diagrams showing a process of forming an alignment film in FIG. 2, and FIG. 5 is a graph showing polarization degree of an alignment film according to voltage intensity.

First, a step of preparing a first substrate 100 and / or a second substrate 200 on which electrodes such as the pixel electrode 109 or the common electrode 209 are formed is performed.

Of course, a gate line and a data line are formed on the first substrate 100 before the pixel electrode 109 is formed, and a thin film transistor is formed in a crossing area between the gate line and the data line. At this time, an insulating film is interposed between the gate line and the data line, and a protective film is interposed between the source / drain electrodes constituting the data line and the thin film transistor and the pixel electrode.

On the other hand, a black matrix formed corresponding to the gate lines, the data lines, and the TFTs of the first substrate 100 and the black matrix formed on the second substrate 200 before the common electrode 209 is formed, An R, G, and B color filters formed in the region, and an overcoat layer for further flattening the R, G, and B color filters may be formed.

On the first substrate 100 and / or the second substrate 200 on which the electrodes are formed, a polyimide-based first alignment layer 110 or 210 is formed by a coating method using rollers or the like . At this time, the polyimide first alignment layers 110 and 210 have a functional group of methyl (-CH ₃ ).

Next, on the first substrate 100 and / or the second substrate 200 on which the first alignment layers 110 and 210 are formed, methyl acrylate or dimethylamine acrylate having a functional group (or functional group) The second alignment film materials 120 and 220 are respectively formed by coating the acrylate of the same methyl series using the roller printing method or the like. The second alignment film material 120, 220 is bonded to the functional group of -CH ₃ of the first alignment film 110, 210.

The step of preparing the soft mold 400 on the first substrate 100 and the second substrate 200 on which the first alignment layers 110 and 210 and the second alignment layer materials 120 and 220 are formed, Loses.

That is to say, the first substrate 100 and / or the second alignment film materials 120 and 220, in which the first alignment layers 110 and 210 and the second alignment layer materials 120 and 220 are formed, The second substrate 200 can also be represented as being carried in.

Here, the soft mold 400 is formed of PDMS (polydimethylsiloxane) as a material and forms a relief pattern formed at regular intervals on one side or bottom surface of the soft mold 400 and an engraved pattern between the relief patterns, A metal layer 401 made of a conductive material such as chromium (Cr), molybdenum (Mo), chrome alloy, aluminum, copper, or the like is deposited on the lower surface on which the pattern is formed. At this time, the step or height between the embossed and engraved patterns on which the metal layer 401 is deposited is formed in the range of 1 to 10 mu m.

Subsequently, a voltage within a range of approximately 20 V is applied to the electrodes 109 and 209 on the first substrate 100 and / or the second substrate 200 and the metal layer 401 of the soft mold 400 .

At this time, as shown in FIG. 5, the higher the voltage is, the higher the degree of polarization will be. For example, when a voltage of 20 V is applied to the electrodes 109 and 209 on the first substrate 100 and / or the second substrate 200 and the metal layer 401 of the soft mold 400 for 2 minutes, The degree of polarization of the first and second electrodes 120 and 220 can reach almost 100%.

For example, a positive voltage is applied from the outermost portion of the metal layer 401 of the soft mold 400 to the inside of the equipment provided with the soft mold 400, and the first substrate 100 and the second substrate (-) voltage is applied from the outermost part of the electrode of the first electrode 200. At this time, the applied voltage may be any one of a voltage greater than about 0 V and less than about 20 V, and voltages of different sizes may be different from each other in a case where the pretilt angles formed by the second alignment film materials 120 and 220 are different from each other .

4A, the soft mold 400 and the second alignment film materials 120 and 220 of the first substrate 100 and / or the second substrate 200 are aligned with each other according to the intensity of the voltage, A step of adjusting the degree of contact between the electrodes is performed.

As shown in FIG. 4B, the center portion of the soft mold 400 is slightly lifted at the intaglio portion of the soft mold 400 according to the intensity of the voltage, so that the hill-shaped microgrooves are uniformly formed, The functional groups having strong polarization are reacted to form the second alignment layers 120a and 220a by being entangled like an electric field by an electric field, and the alignment in a certain direction is performed, thereby determining the pretilt angle.

In this case, even if the first substrate 100 and the second substrate 200 have a large area, the intensity of the voltage can be uniformly maintained in all regions, and the intensity of the voltage The microgrooves of the second alignment layers 120 and 220 may be formed as fine as possible while forming a pretilt angle according to the intensity of the electric field.

Although not shown in the drawing, a conductive seal line is applied to the outer portions of the first substrate 100 or the second substrate 200, which are microgrooves and aligned.

In addition, as shown in FIG. 4C, a liquid crystal 301 is formed in the inside of the conductive chamber line, that is, the portion forming the image region of the liquid crystal display element.

Then, the liquid crystal layer 301 is formed by uniformly diffusing the liquid crystal 301 by the process of attaching the first substrate 100 and the second substrate 200 together.

1A is a view showing an orientation film forming process using a roller printing method

1B is a perspective view schematically showing a general rubbing process.

2 is a cross-sectional view showing the structure of the liquid crystal display device and the polarity of the alignment film according to the present invention

FIG. 3 is a schematic cross-sectional view illustrating the structure of the first and second alignment layers shown in FIG.

Figs. 4A and 4C are diagrams showing the alignment film formation process of Fig. 2

5 is a graph showing the degree of polarization of an orientation film according to the intensity of voltage

Claims (9)

A first substrate on which a thin film transistor is formed; A second substrate bonded to the first substrate and opposite to the first substrate, the second substrate having a black matrix and a color filter; A first alignment layer formed on at least one of the first substrate and the second substrate and having a functional group of methyl (-CH ₃ ); A second alignment layer formed on the first alignment layer, the second alignment layer being bonded to the methyl to form a microgroove so as to have a predetermined angle of view; And And a liquid crystal layer formed by injecting liquid crystal between the first substrate and the second substrate. [2] The liquid crystal display of claim 1, wherein the second alignment layer is formed of methyl acrylate or methyl acrylate of dimethylamino acrylate. Providing a first substrate and a second substrate; Forming an electrode on at least one of the first substrate and the second substrate; Forming a polyimide-based first alignment layer on the substrate on which the electrode is formed; Forming a second alignment layer material having a functional group on the first alignment layer; Providing a soft mold in which a relief pattern is formed at regular intervals on a bottom surface and an engraved pattern is formed between the relief patterns and a metal layer is formed on the relief pattern and the relief pattern on a substrate on which the second alignment film material is formed; Applying a voltage between the metal layer of the soft mold and an electrode on the substrate; A soft mold is imprinted on the second alignment film material on the substrate to form a microgroove by an electric field and a second alignment film is formed by orienting the second alignment film material so as to have a predetermined square- ; And And forming a liquid crystal layer by bonding the first substrate and the second substrate on which the second alignment layer is formed. 4. The method of claim 3, wherein providing the first substrate comprises: Forming a gate electrode and a gate line on the first substrate; Forming an insulating film on the first substrate on which the gate electrode and the gate line are formed; Forming a data line crossing the gate line and a source / drain electrode partially overlapping the gate electrode on a first substrate on which the insulating film is formed; And Forming a protective film on the first substrate; and forming a protective film on the first substrate. 4. The method of claim 3, wherein providing the second substrate further comprises: Forming a black matrix on the second substrate to intersect the unit pixel regions; And And forming color filters of R, G, and B in the unit pixel region partitioned by the black matrix. The method of manufacturing a liquid crystal display element according to claim 3, wherein the electrode is one of a pixel electrode of the first substrate and a common electrode of the second substrate. [4] The method of claim 3, wherein the second alignment layer comprises methyl acrylate or methyl acrylate of dimethylamine acrylate. 4. The method of manufacturing a liquid crystal display element according to claim 3, wherein the voltage Vx applied between the metal layer of the soft mold and the substrate is in a range of 0 V <Vx <20 V. 9. The method of claim 8, wherein the second alignment layer is formed by differently forming the first alignment layer in accordance with different applied voltages.

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