KR101066477B1 - Liquid Crystal Display Device And Method For Fabricating The Same - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method of manufacturing the liquid crystal display device to improve the adhesive properties between the overcoat layer and the substrate by further comprising an adhesion promoter layer between the overcoat layer and the substrate, the liquid crystal display device of the present invention comprises a plurality of gates A first substrate on which a thin film transistor is formed at a portion where wiring and data wiring cross, a second substrate facing the first substrate, and having a black matrix and a color filter layer formed thereon, and formed on the entire surface including the color filter layer; An overcoat layer, an adhesion promoter layer interposed between the second substrate and the overcoat layer on which the black matrix and the color filter layer are not formed, and a sealant for opposing the first and second substrates. It is characterized by.

Overcoat Layer, Adhesive Properties, Sealant, Adhesive Promoter Layer

Description

Liquid Crystal Display Device and Method for Manufacturing the Same {Liquid Crystal Display Device And Method For Fabricating The Same}

1 is a cross-sectional view of a liquid crystal display device according to the prior art.

2A to 2D are cross-sectional views of a liquid crystal display device according to the prior art.

3 is a cross-sectional view of a liquid crystal display device according to another embodiment of the prior art.

4 is a cross-sectional view of a liquid crystal display device according to the present invention.

5a to 5d is a polymerization process of the adhesion promoter layer according to the present invention.

6A to 6D are cross-sectional views of a liquid crystal display device according to the present invention.

* Explanation of symbols on the main parts of the drawings

111 TFT Array Substrate 117 Pixel Electrode

118: common electrode 121: color filter array substrate

122: black matrix 123: color filter layer

124: overcoat layer 129: liquid crystal layer

131: column spacer 141: sealant

150: adhesive promoter layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device (LCD), and more particularly, to a liquid crystal display device and a method of manufacturing the same for improving adhesion characteristics between an overcoat layer and a substrate formed for surface planarization.

Recently, the liquid crystal display device has a high contrast ratio, is suitable for gray scale display or moving image display, and has low power consumption. Therefore, the liquid crystal display device is gradually used as an alternative means to overcome the disadvantage of cathode ray tube (CRT). It is expanding.

Such a liquid crystal display device typically includes a TFT array substrate in which a thin film transistor and a pixel electrode are formed in each unit pixel defined by a gate wiring and a data wiring, and a color filter array in which a black matrix, a color filter layer, and a common electrode are formed. It consists of a substrate and a liquid crystal layer interposed between the two substrates and the array direction is controlled by a vertical electric field formed between the pixel electrode and the common electrode to display an image by various external signals.

At this time, the common electrode may be formed between the pixel electrodes on the TFT array substrate. In this case, the alignment direction is controlled by the transverse electric field generated between the pixel electrode and the common electrode.

Hereinafter, a liquid crystal display device and a method of manufacturing the same according to the related art will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a liquid crystal display device according to the prior art, Figures 2a to 2d is a process cross-sectional view of the liquid crystal display device according to the prior art, Figure 3 is a cross-sectional view of a liquid crystal display device according to another embodiment of the prior art.

In the liquid crystal display device according to the related art, as shown in FIG. 1, the color filter array substrate 21 as the upper substrate and the TFT (Thin Film Transistor) array substrate 11 as the lower substrate are opposed to each other. Arranged to form a liquid crystal layer 29 having dielectric anisotropy therebetween, and switching a TFT added to hundreds of thousands of unit pixels through a pixel selection gate wiring to apply a voltage to the pixel. Driven in a manner.

Specifically, in the TFT array substrate 11, a gate line (not shown) and a data line 15 are arranged to cross each other to define a sub-pixel, and the gate line and the data line cross each other. A thin film transistor (TFT) for switching a voltage on / off is formed in the portion to change the alignment direction of liquid crystal molecules, and is electrically connected to the thin film transistor in each unit pixel to apply a voltage to the liquid crystal layer 29. A common electrode 18 is formed to be spaced apart from the pixel electrode 17 and the pixel electrode 17 at regular intervals so as to generate a transverse electric field along with the pixel electrode 17 to control the liquid crystal direction.

In addition, the color filter array substrate 21 includes red, green, and blue color filter layers 23, R, G, and B, which are arranged in a predetermined order for each unit pixel to implement colors. The black matrix 22 which serves as the division and light blocking between the cells and the overcoat layer 24 formed on the entire surface including the color filter layer 23 to planarize the surface are formed.                         

The sealant 41 is further provided at edges of the color filter array substrate 21 and the TFT array substrate 11 to completely adhere the two substrates and prevent liquid crystals from flowing out. The column spacer 31 is further provided to keep the substrate gap constant.

Looking at the manufacturing process of such a liquid crystal display device as follows.

First, as shown in FIG. 2A, the resin BM is coated on a predetermined portion of the color filter array substrate 21 and then patterned to form a black matrix 22, and then R is formed on the entire surface including the black matrix 22. (Red) A color resist colored with color is applied and patterned to form a color filter layer of R color. A color filter layer of G (Green) color and a color filter layer of B (Blue) color are also formed in the same manner to complete the color filter layers 23 of R, G, and B.

Subsequently, the color filter array substrate 21 is cleaned to remove dust and foreign matter on the color filter layer. Then, as shown in FIG. 2B, the color filter layer 23 is replaced to planarize the surface of the color filter array substrate 21. An overcoat layer 24 is formed by coating an acrylic resin, which is an organic material, on the entire surface thereof.

As described above, after the overcoat layer 24 is formed, the flowable acrylic resin is irradiated with UV and cured. The acrylic resin is a photocurable material and is cured by light (UV).

At this time, since the overcoat layer 24 formed of acrylic resin has poor adhesion characteristics with the substrate 21 and the sealant 41, the seed coat 41 is removed to remove the overcoat layer 24 at the portion where the sealant 41 is to be formed. The Japanese 41 is directly bonded to the substrate 21.                         

As described above, in order to remove the overcoat layer 24 of the portion in which the sealant 41 is formed, a patterning process should be performed. When curing the overcoat layer 24, UV is irradiated to perform a separate exposure process. You do not have to do. That is, since the curing process and the exposure process of the overcoat layer is performed at the same time, the number of exposure processes can be reduced.

Thereafter, the overcoat layer 24 subjected to the exposure process is developed, and the overcoat layer 24 of the portion where the sealant 41 is to be formed is removed and patterned, as shown in FIG. 2D, and then the overcoat layer 24 is patterned. To form a column spacer 31.

Subsequently, after printing the sealant 41 serving as an adhesive on the edge of the TFT array substrate 21 on which the thin film transistor is formed, the two substrates are opposed to each other, and the high pressure and the hot pressure are about 180 ° C. The sealant 41 is cured by using heat to completely bond it.

At this time, the sealant 41 is disposed at the edge of the color filter array substrate 21 from which the overcoat layer 24 is removed.

Thereafter, a scribe / break process is performed on the opposingly bonded color filter array substrate 21 and the TFT array substrate 21 to complete the liquid crystal display device.

At this time, the liquid crystal layer formed between the two substrates is a liquid crystal injection method for injecting the liquid crystal between the two substrates using a capillary phenomenon after the substrate is bonded to the inside of the liquid crystal cell and the liquid crystal is dropped into one of the substrates After spreading evenly, it can be formed by the liquid crystal dropping method of bonding the substrate.

However, as described above, when the overcoat layer 24 is formed using an acrylic resin having photocuring properties, a photoetch process including an exposure process must be performed, thereby increasing the process time.

Therefore, in order to shorten the process time, it is a trend to replace the acrylic resin of the thermosetting properties cured by heat. As described above, when cured with heat, the process time and the process cost can be significantly reduced compared to the cured by irradiation with UV using expensive exposure equipment.

However, when hardening the overcoat layer of a thermosetting characteristic as heat, the exposure process is not included and patterning of the overcoat layer by a photo process is impossible. As a result, as shown in FIG. 3, the overcoat layer 24 is coated on the entire surface of the substrate 21, so that the sealant 41 does not directly adhere to the substrate 21 and the overcoat layer 24 having weak adhesive properties. To bond.

Therefore, in a subsequent sealant curing process or scribe / brake process, an interface ruptures between the overcoat layer 24 and the sealant 41 or between the overcoat layer 24 and the substrate 21 by stress due to heat and pressure. (A) is generated.

In the future, the front coating using the thermosetting acrylic resin is continued in the model applying the overcoat layer, which improves the interface adhesion between the overcoat layer 24 and the sealant 41 or the overcoat layer 24 and the substrate 21. It is most important to do.

The conventional liquid crystal display device and its manufacturing method have the following problems.

That is, when using an overcoat layer having a photocuring property to planarize the surface of the substrate on which various patterns are formed, the curing process and the exposure process of the overcoat layer are simultaneously performed to remove the overcoat layer of the portion where the sealant is formed. It can be, but there is a problem that the process time is long by the photo-process of the overcoat layer.

In addition, in the case of forming the overcoat layer of the photocurable properties, since the expensive exposure equipment must be used, the process cost has increased.

Therefore, the trend of replacing the overcoat layer of the thermosetting characteristics in recent years, when using the overcoat layer of the thermosetting characteristics, the overcoat layer is formed on the entire surface of the substrate because the photo process is not performed.

However, in this case, the adhesion property between the overcoat layer, which is an organic material, and the substrate, which is an inorganic material, is low, so that adhesion may be degraded by heat and pressure in the sealant curing process and the scribe / break process.

Defects that may occur due to poor contact with the overcoat layer include unfilled liquid crystals and the periphery of the sealant, resulting in uneven gaps.

The present invention has been made to solve the above problems, in the model of forming an overcoat layer of the thermosetting characteristics to planarize the surface of the color filter array substrate and the TFT array substrate, the adhesion characteristics of the overcoat layer and the substrate It is an object of the present invention to provide a liquid crystal display device and a method of manufacturing the same to improve the efficiency.

According to an aspect of the present invention, a liquid crystal display device includes a first substrate having a thin film transistor formed at a portion where a plurality of gate lines and data lines cross each other, and a black matrix and a color filter layer facing the first substrate. The formed second substrate, the overcoat layer formed on the entire surface including the color filter layer, the adhesion promoter layer inserted between the second substrate and the overcoat layer on which the black matrix and the color filter layer are not formed, And a sealant for opposing and bonding the first and second substrates.

In addition, a method of manufacturing a liquid crystal display device for achieving another object of the present invention includes providing a first substrate and a second substrate, forming a black matrix and a color filter layer on the inner surface of the first substrate, Forming an adhesion promoter layer on the first substrate on which the black matrix and the color filter layer are not formed, forming an overcoat layer on the entire surface of the first substrate including the adhesion promoter layer, and Forming a sealant at an edge to face each other, and forming a liquid crystal layer between the first and second substrates.

This technical feature of the present invention is applied to a liquid crystal display device forming an overcoat layer on top of various patterns for surface planarization.

Hereinafter, an embodiment will be described only in the case where an overcoat layer is formed on a color filter array substrate in a liquid crystal display device that controls the liquid crystal array by a transverse electric field. However, the present invention is not limited thereto.

Hereinafter, a liquid crystal display device and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a cross-sectional view of the liquid crystal display device according to the present invention, Figures 5a to 5d is a polymerization process diagram of the adhesion promoter layer according to the present invention, Figure 6a to 6d is a process cross-sectional view of the liquid crystal display device according to the present invention. .

As shown in FIG. 4, the liquid crystal display according to the present invention is formed at the intersection of the gate wiring (not shown) and the data wiring 115 and the two wirings, which are insulated from each other by the gate insulating film 113. The thin film transistor TFT, the pixel electrode 117 penetrating the passivation layer 116 and connected to the thin film transistor TFT, and the common electrode 118 disposed in parallel with the pixel electrode 117 to generate a transverse electric field. A TFT array substrate 111 having a), a color filter array substrate 121 having a black matrix 122, a color filter layer 123, an overcoat layer 124, and an adhesion promoter layer 150 formed thereon, It consists of a liquid crystal layer 129 interposed between the two substrates, by applying a voltage to the electrode to rearrange the liquid crystal molecules of the liquid crystal layer to adjust the amount of light transmitted to display an image.

In order to completely bond the TFT array substrate and the color filter array substrate, a sealant 126 is further provided at an edge of the substrate outside the image display area, and a column spacer 131 for maintaining a gap between the two substrates is provided. It is further provided.

At this time, the overcoat layer 124 is an acrylic resin having a thermosetting property, and the photocoat process is not performed so that the overcoat layer 124 is applied to the entire surface of the substrate 121. Here, the adhesion promoter layer 150 is further inserted therebetween in order to improve the adhesion characteristics of the substrate 121 and the overcoat layer 124. As a result, bursting at the interface between the substrate 121 and the overcoat layer 124 is prevented, thereby improving productivity.                     

 The adhesive promoter layer 150 may generally use allyltrichlorosilane. The allyltrichlorosilane has a molecular weight of 172.52 g / mol, a boiling point of 116 ° C., and above all, selective to a glass surface. It characterized in that it comprises a trichlorosilane (trichlorosilane) which is a functional group capable of adsorption.

For this reason, the formation of the monolayer film aligned on the substrate surface is possible. In addition, by including a vinyl group of a carbon double bond of allyl trichlorosilane, it participates in the acrylic polymer polymerization, which is the overcoat layer 124, thereby improving the contact characteristics between the interface between the overcoat layer 124 and the adhesion promoter layer 150. can do.

Since the adhesive promoter layer 150 is adsorbed on the surface of the glass substrate, the adhesion promoter layer 150 has little effect on the polymer polymerization reaction of the color filter layer 123 and the overcoat layer 124. Does not affect the coating uniformity.

Here, look at the polymerization mechanism of the adhesion promoter layer 150 in detail as follows.

First, as shown in FIG. 5A, when the substrate 121 is dipped into a chemical solution containing allyl trichlorosilane, which is a material for the adhesion promoter layer, chlorine (Cl) of allyl trichlorosilane may be formed on the glass substrate 121. Hydrogen chloride (HCl) is released by reacting with hydrogen (H) in the hydroxyl group (OH), so that the silicon ions (Si) of allyltrichlorosilane are bonded to the oxygen ions (O) of the hydroxyl group.                     

As a result, as shown in FIG. 5B, the substrate 121 and the adhesion promoter layer 150 are bonded by chemical bonding.

Subsequently, as shown in FIG. 5C, when the acrylic resin, which is an overcoat material, is coated on the substrate 121 on which the adhesion promoter layer 150 is formed, the vinyl group (C = C) of the adhesion promoter layer 150 is acrylic. Participate in the polymerization to form chemical bonds.

As a result, as shown in FIG. 5D, the adhesion promoter layer 150 and the overcoat layer 124 are bonded by chemical bonding.

In this way, the allyl trichlorosilane, which is the adhesion promoter layer 150, is well adhered to the substrate 121 by trichlorosilane, and is also well adhered to the overcoat layer 124 by a vinyl group to form the substrate 121 and the overcoat layer 124. Improves adhesive properties. Therefore, stability against heat and physical stress during the cell process may be improved, and the sealing property of the cell may be improved to prevent unfilling of the liquid crystal and defects around the sealant.

Looking at the liquid crystal display device in detail through the manufacturing method as follows.

First, as illustrated in FIG. 6A, the black matrix 122 is formed on the color filter array substrate 121 to block light leakage in a region in which liquid crystal cannot be controlled. The black matrix 122 is formed by coating a resin BM, which is a carbon-based organic material, and patterning it by a photolithograpy technique.

Thereafter, the color filter layers 123 colored with R, G, and B are formed on the black matrix 122 using dyeing, electrodeposition, pigment dispersion, coating, and the like.

Subsequently, as shown in FIG. 6B, the color filter array substrate 121 is dipped into the process chamber to form an adhesion promoter 150 on the substrate surface. The adhesion promoter layer 150 is formed on the surface of the substrate on which the color filter layer 123 and the black matrix 122 are not formed, and serves to improve adhesion characteristics between the overcoat layer 124 and the substrate 121. Even if the adhesive promoter layer 150 is coated on the color filter layer 123, it does not affect the characteristics of the color filter layer 123, so it is irrelevant.

At this time, the process chamber is filled with a chemical solution consisting of a solvent and allyl trichlorosilane of 0.001 ~ 0.005M, IPA (Isopropyl alcohol) and ethanol (ethanol) may be used as the solvent.

For reference, in addition to the dipping method using the chemical solution as described above, the adhesive coater layer 150 may be formed by the spray method.

Next, an overcoat layer 124 is formed by coating an acrylic resin having a thermosetting property on the entire surface including the adhesion promoter layer 150 and the color filter layer 123. At this time, the adhesion promoter layer 150 is present on the surface of the substrate 121 to enhance the adhesion with the substrate. Therefore, process stability in the scribing / breaking process after the cell process can be increased, and unfilling of the liquid crystal and impurity penetration can be prevented due to enhanced adhesion between the substrate and the overcoat layer.

Subsequently, the overcoat layer 124 is cured by heat, and then a plurality of column spacers 131 of FIG. 5D are formed at predetermined portions of the overcoat layer 124.

Next, as shown in FIG. 5D, after the gate line (not shown) and the data line 115 are formed on the TFT array substrate 121, and the thin film transistor TFT is formed at a portion where the two lines cross each other. The common electrode 118 and the pixel electrode 117 which are alternately arranged in parallel in the unit pixel are formed.

Subsequently, a sealant 141 is formed on the edge of the substrate by screen printing, dispensing, or the like using a polymer having excellent adhesiveness such as an epoxy resin, and is bonded to the color filter array substrate 121.

Thereafter, by applying high heat or pressure to the two bonded substrates as described above, the sealant is cured while maintaining a constant gap between the substrates, thereby completely bonding the two substrates.

Next, the two bonded substrates are cut to a desired product size by performing a scribe process and a break process.

That is, a scribe process is performed to form a crack using a scribe wheel having a constant pressure and speed on the surface of the color filter substrate in order to cut the two bonded substrates to the required size. In this case, the scribe wheel is made of a material having a higher hardness than the transparent glass substrate.

Subsequently, the liquid crystal panel is inverted and subjected to direct impact using a break bar on the thin film array substrate along the portion where the crack is formed, thereby separating the liquid crystal panel into cells having a desired size of the liquid crystal panel.

Next, a liquid crystal panel having a required size is obtained by injecting and encapsulating a liquid crystal between the two substrates cut as described above through the liquid crystal inlet.

That is, the bonded liquid crystal cell is introduced into the vacuum chamber to immerse the liquid crystal inlet in the liquid crystal tray, vacuum degassing the inside of the cell, and supply the inert gas to make the vacuum chamber at atmospheric pressure. At this time, the liquid crystal is injected between the substrate due to the difference in the atmospheric pressure between the liquid crystal cell and the vacuum chamber. Nitrogen (N ₂ ) gas is used as the inert gas, and the liquid crystal injection rate is determined by the gas supply rate.

In recent years, as the liquid crystal display device is enlarged in size, the liquid crystal dropping method does not depend on the above-mentioned liquid crystal injection method, but also the liquid crystal dropping method of forming a liquid crystal layer by dropping and spreading the liquid crystal evenly on the inner surface of the substrate before the substrate opposing bonding.

Thus, the liquid crystal display device according to the present invention is completed.

As such, the substrate and the overcoat layer bonded by the present invention do not burst or fall even in the scribe / break process and the liquid crystal filling process as described above. This is because the adhesion promoter layer interposed between the substrate and the overcoat layer maintains the rm adhesion characteristics.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

As described above, the liquid crystal display device and the manufacturing method thereof according to the present invention have the following effects.                     

By further inserting the contact promoter layer between the substrate and the overcoat layer, the interfacial adhesion between the substrate and the overcoat layer is enhanced.

Therefore, the stability against heat and physical stress during the cell process is improved, and the sealing property of the cell can be improved to prevent unfilling of the liquid crystal and defects around the sealant.

Claims (9)

A first substrate having a thin film transistor formed at a portion where a plurality of gate lines and data lines cross each other; A second substrate facing the first substrate and having a black matrix and a color filter layer formed thereon; An overcoat layer formed on the entire surface including the color filter layer; An adhesion promoter layer interposed between the second substrate and the overcoat layer on which the black matrix and the color filter layer are not formed; And a sealant for opposing and bonding the first and second substrates together. The method of claim 1, The overcoat layer is a liquid crystal display device, characterized in that the thermosetting acrylic resin. The liquid crystal display device of claim 1, wherein the adhesion promoter layer is allyltrichlorosilane. Providing a first substrate and a second substrate; Forming a black matrix and a color filter layer on an inner surface of the first substrate; Forming an adhesion promoter layer on the first substrate on which the black matrix and the color filter layer are not formed; Forming an overcoat layer on the entire surface including the adhesive promoter layer; Forming a sealant on an edge of the first substrate or the second substrate to face each other; And forming a liquid crystal layer between the first and second substrates. The method of claim 4, wherein The adhesive promoter layer A method for manufacturing a liquid crystal display device, comprising trichlorosilane, which is a functional group that can be selectively adsorbed on a glass surface, to be formed using a dipping method or a spraying method. The method of claim 4, wherein And after the forming of the overcoat layer, thermosetting the overcoat layer. The method of claim 4, wherein the overcoat layer is formed using an acrylic resin. The method of claim 4, wherein the adhesion promoter layer is formed using allyltrichlorosilane. The method of claim 4, wherein the adhesion promoter layer, Allyl trichlorosilane of 0.001-0.005M, Method of manufacturing a liquid crystal display device characterized in that it is formed using a chemical solution consisting of a solvent of IPA (Isopropyl alcohol) or ethanol (ethanol).

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