KR20030094849A - Method for fabricating of liquid crystal display device - Google Patents

Abstract

PURPOSE: A method for manufacturing a liquid crystal display is provided to maintain a cell gap surrounding a sealant to be the same as the cell gap of an active area without mixing glass fiber with the sealant, thereby realizing equal brightness in a whole picture. CONSTITUTION: Thin film transistors(501), pixel electrodes, a first alignment film(502), and a plurality of ball spacers(503,503a) are sequentially formed on a lower substrate(500). Black matrices, a color filter layer(511), an overcoat layer(512), a common electrode(513), and a second alignment film(514) are sequentially formed on an upper substrate(510). A sealant(515) is applied on an edge of an active area of the upper substrate or the lower substrate. The plurality of ball spacers are formed at the active area and a dummy area. The lower substrate is bonded with the upper substrate before cutting the dummy area.

Description

Manufacturing method of liquid crystal display device {METHOD FOR FABRICATING OF LIQUID CRYSTAL DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a manufacturing method of a liquid crystal display device capable of maintaining a uniform cell gap inside and outside the seal material.

As the information society develops, the demand for display devices is gradually increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and VFDs (Vacuum) Various flat panel display devices such as fluorescent display have been studied, and some are already used as display devices in various devices.

Among them, LCD is the most used as a substitute for CRT (Cathode Ray Tube) for mobile image display device because of the excellent image quality, light weight, thinness, and low power consumption. In addition to mobile type such as notebook computer monitor, BACKGROUND ART Various developments have been made in televisions and computer monitors for receiving and displaying broadcast signals.

Although various technical advances have been made in order for such a liquid crystal display device to serve as a screen display device in various fields, the task of improving the quality of an image as a screen display device is often arranged with the above characteristics and advantages. Therefore, in order to use a liquid crystal display as a general screen display device in various parts, it is a matter of how high quality images such as high definition, high brightness, and large area can be realized while maintaining the characteristics of light weight, thinness, and low power consumption. Can be.

Such a liquid crystal display device may be classified into a liquid crystal panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel. The liquid crystal panel has a predetermined space and has an upper and lower substrates bonded to each other. It is composed of a liquid crystal layer formed between the lower substrate.

Here, the lower substrate (TFT array substrate) includes a plurality of gate lines arranged in one direction at a predetermined interval, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, and the respective gate lines. A plurality of pixel electrodes formed in a matrix form in each pixel region defined by intersections of the data lines and a plurality of thin film transistors switched by signals of the gate lines to transfer the signals of the data lines to the pixel electrodes. Is formed.

In the upper substrate (color filter substrate), a black matrix layer for blocking light except for the pixel region, an R, G, and B color filter layer for expressing color colors, and a common electrode for implementing an image are formed. do.

In addition, the upper substrate and the lower substrate thus formed have a predetermined space by a spacer for maintaining a cell gap, and are bonded by a sealant. And liquid crystal is formed in the space inside a seal material.

When manufacturing a liquid crystal display device having such a structure, instead of forming one liquid crystal panel on one substrate, a plurality of liquid crystal panels are simultaneously formed on one large substrate according to the size of the substrate and the size of the liquid crystal panel.

FIG. 1 is a plan view of a general liquid crystal panel (LCP) before a cutting process, and shows two upper substrates 100 in a main board and a seal material 110 applied in each upper substrate 100. The dotted line shows a scribe line for cutting each upper substrate 100.

FIG. 1 shows a diagram for forming two panels in a main board, but this is only an example, and the number of branches that cells can emerge through the main board is the area of the main board and the panel formed on the main board. It may vary depending on the size.

A method of manufacturing a liquid crystal display device having such a structure is divided into a vacuum injection method and a liquid crystal drop method according to a method of forming a liquid crystal layer between the lower substrate and the upper substrate, which will be described below.

First, the manufacturing method of the liquid crystal display device by the vacuum injection method is as follows.

First, a lower substrate including a thin film transistor and a pixel electrode, and an upper substrate including a black matrix, a color filter layer, and a common electrode are prepared.

Then, the sealing material is applied to any one of the substrates so as to prevent the liquid crystal from leaking out and to adhere the two substrates.

In this case, as the seal material, a thermosetting seal material using an epoxy resin or the like is mainly used.

The ball spacers are randomly distributed on the lower substrate.

Thereafter, the two substrates are bonded together and then heated to cure the thermosetting seal material, thereby bonding both substrates.

Then, after cutting each panel to form a unit panel, the unit panel is placed in a vacuum chamber to maintain the inside of the substrate in a vacuum state, and then immersed in a liquid crystal container to form a liquid crystal layer in the bonded substrate.

However, such a vacuum injection method has a problem in that productivity is reduced because the liquid crystal injection time takes a long time as the display screen becomes larger.

The liquid crystal dropping method is to solve the above problems of the vacuum injection method, and the lower substrate and the upper substrate preparation step, the spacer forming step, and the sealing material coating step are the same as the vacuum injection method.

However, if the liquid crystal dropping method is different from the vacuum injection method, the liquid crystal layer is not injected into the vacuum state after the two substrates are bonded, but the liquid crystal is dropped between the sealing materials formed on the substrate and then the bonding process of both substrates is performed. It is.

On the other hand, if the thermosetting or UV curing seal material used in the vacuum injection method or liquid crystal dropping method is composed of only an epoxy resin or acrylic resin can not be fully compressed in the bonding process to maintain the cell gap.

Therefore, glass fibers are mixed with an epoxy resin or an acrylic resin to maintain a predetermined cell gap.

Hereinafter, a method of manufacturing a conventional liquid crystal display device having a seal material formed by mixing glass fibers will be described with reference to the accompanying drawings.

2 is a structural cross-sectional view of a conventional liquid crystal display device before the cutting process taken along the line II ′ of FIG. 1, and FIGS. 3A and 3B are schematic structural cross-sectional views of a conventional liquid crystal display device after the cutting process according to the glass fiber of the seal material.

4 is a graph showing light transmittance characteristics according to a cell gap of a liquid crystal display device.

In the related art, a method of manufacturing a liquid crystal display device is formed by forming components on the lower substrate 200 and the upper substrate 210, and then bonding the two substrates 200 and 210 and then cutting them.

As shown in FIG. 2, the thin film transistor 201, the first alignment layer 202, and the ball spacer 203 are formed in the lower substrate 200 in the order of processing. It is formed only in an area, that is, an active area.

In addition, in forming the black matrix, the color filter layer 211, the overcoat layer 212, the common electrode 213, and the second alignment layer 214 on the upper substrate 210 in the process order, the respective components are also sealed. (215) is formed only in the active region inside.

That is, the components are not formed in the dummy region of each substrate to be cut out by the scribe line.

The seal material 215 is used by mixing glass fibers in an epoxy resin or an acrylic resin.

The mixing and using of the glass fiber in the seal material 215 is to maintain the cell gap when the upper substrate and the lower substrate are bonded together, but if the density and size of the glass fiber are not uniform enough to maintain the cell gap, Figs. As shown in FIG. 3B, after cutting the scribe line, a difference occurs between the cell gap of the active region and the cell gap around the seal.

The cell gap will be divided into a case where the cell gap around the seal material is larger than the cell gap of the active area as shown in FIG. 3A and a case where the cell gap around the seal material is smaller than the cell gap of the active area as shown in FIG. 3B. Can be.

As described above, when the cell gap difference is caused by the glass fiber, the light transmittance of the active area and the seal material peripheral part is generated, and thus, the brightness of the screen is uneven.

For example, when the cell gap is formed to have 4 to 5 μm, as shown in FIG. 3A, when the cell gap around the seal material is larger than the cell gap of the active area, as shown in FIG. 4, light at the seal periphery is greater than in the active area. The more light transmission occurs, the more uneven brightness of the screen.

In addition, as shown in FIG. 3B, when the cell gap around the seal material is smaller than the cell gap of the active area, as shown in FIG. 4, less light is transmitted through the seal area than in the active area, resulting in uneven brightness of the screen. .

The above phenomenon appears when the normal white mode of the LCD using a normal TN liquid crystal. When the normal black mode other than the normal white mode as described above, the opposite phenomenon appears. Also, a problem of uneven brightness of the screen is derived.

In other words, in normal black mode, when the cell gap around the seal material becomes smaller, the screen transmittance around the seal material becomes higher, and when the cell gap around the seal material is larger, the screen transmittance around the seal material becomes lower. As in the case of the white mode, the variation in screen brightness is caused by the variation in transmittance around the sealing material.

For reference, in the normal black mode, the data curve of FIG. 4 shows a vertically symmetrical shape.

In addition to the problems caused by the difference in size and density of the glass fiber as described above, a problem may occur in the metal pad for connecting the gate line and the source line formed on the lower substrate due to the material properties of the glass fiber. have.

In addition, since the glass fiber must be mixed and used separately in the sealing material, a problem occurs due to the additional material cost.

The present invention has been made to solve the above problems, in particular, the manufacturing of a liquid crystal display device that can maintain a uniform cell gap between the active region and the seal material even without the use of glass fiber in the seal material The purpose is to provide a method.

1 is a plan view of a liquid crystal panel (LCP) before a general cutting process

2 is a structural cross-sectional view of a conventional liquid crystal display before cutting process

3A and 3B are schematic structural cross-sectional views of a conventional liquid crystal display after the cutting process

4 is a data diagram showing light transmittance characteristics according to a cell gap of a liquid crystal display device.

5A and 5B are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention having a ball spacer.

6A and 6B are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention having column spacers.

Explanation of symbols on the main parts of the drawings

500: lower substrate 501: thin film transistor

502: first alignment film 503, 503a: ball spacer

510: upper substrate 511: color filter layer

512: overcoat layer 513: common electrode

514: second alignment film 515: seal oil

516, 516a: column spacer

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, the method comprising: a lower substrate and an upper substrate having active regions and dummy regions defined on a scribe line; Applying a seal material to an edge of an active region of the active material; forming a spacer in an active region and a dummy region of the lower substrate or the upper substrate; and bonding the lower substrate and the upper substrate to cut the dummy region. Characterized in that.

In addition, the method of manufacturing a liquid crystal display device according to the present invention is a method of manufacturing a liquid crystal display device having a lower substrate and an upper substrate having an active region and a dummy region defined on the basis of a scribe line. Forming a thin film transistor, a pixel electrode, and a first alignment layer on the lower substrate in sequence, applying a seal material to an edge of an active region of the upper substrate, and forming a black matrix and a color on the upper substrate where an active region and a dummy region are defined. And sequentially forming a filter layer, a common electrode, and a second alignment layer, and forming spacers in an active region and a dummy region of the lower substrate or the upper substrate.

The seal material is characterized in that the epoxy resin is not mixed with glass fibers (glass fiber).

And the seal material is characterized in that the glass fiber (glass fiber) is not mixed acrylic resin.

The spacer may be a ball spacer or a column spacer.

And the column spacer is characterized by consisting of a photosensitive organic resin.

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

5A and 5B are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention having a ball spacer, and FIGS. 6A and 6B illustrate a liquid crystal display according to an exemplary embodiment of the present invention having column spacers. It is a process sectional drawing which shows the manufacturing method of a device.

First, the present invention is to form a spacer for maintaining the cell gap not only in the active region but also in the dummy region (region to be cut by the cutting process) in order to maintain the cell gap evenly without mixing the glass fiber in the seal material. There is a characteristic.

The manufacturing method of the liquid crystal display device according to the present invention is formed by a process of forming each component on the lower substrate 500 and the upper substrate 510, and bonding the two substrates 500 and 510 and then cutting them.

First, as shown in FIG. 5A, a thin film transistor 501, a pixel electrode, a first alignment layer 502, and a ball spacer 503 are sequentially formed on the lower substrate 500 in a process sequence. .

At this time, the ball spacer 503 is to maintain the cell gap is randomly arranged on the lower substrate 500.

The black substrate, the color filter layer 511, the overcoat layer 512, the common electrode 513, and the second alignment layer 514 are sequentially formed on the upper substrate 510 facing the lower substrate 500. do.

The sealing material 515 is formed to surround the active area of one of the substrates to prevent the liquid crystal between the substrates 500 and 510 from leaking to the outside and to assist the adhesion of the substrates 500 and 510 during the bonding process. do.

The seal material 515 formed to maintain a cell gap between the upper substrate 510 and the lower substrate 500 bonded above is a thermosetting seal material such as an epoxy resin in which glass fibers are not mixed. Or UV-curable sealant such as acrylic resin (applied to the liquid crystal dropping method to be described later).

When the above process is performed on both substrates 500 and 510, the same constituents as in the active region are formed in the dummy region to cut the scribe line by cutting the scribe line around the seal material 515 in the process order. The ball spacer 503a is also formed.

In other words, when the thin film transistor, the pixel electrode, and the first alignment layer are formed in the active region of the upper substrate 510, the thin film transistor, the pixel electrode, and the first alignment layer are formed in the dummy region, and the active region of the lower substrate 500 is formed. When forming the black matrix, the color filter layer, and the common electrode, the black matrix, the color filter layer, and the common electrode are formed in the dummy region, and the ball spacers are formed in the dummy region as well as the active region of the upper substrate 510 and the lower substrate 500. 503 and 503a are formed.

The reason why the ball spacer is also provided in the dummy area is that the cell gap of the active area is bonded when the seal material 515 is bonded, even when only the thermosetting seal material using epoxy resin is used without mixing the glass fiber. In order to be able to maintain the same cell gap around the seal material 515.

By the above, even if glass fibers are not mixed in the sealant 515, the gaps in and out of the active region can be kept the same until the seal curing process is completed.

In addition, by minimizing the difference between the cell gap of the active region and the cell gap around the seal member 515, the light transmittance may be equalized, and thus the screen brightness may be uneven due to the difference in the cell gap.

In addition, the present invention does not need to mix and use the glass fiber in the seal material 515, thereby saving material costs, as well as scratches on the metal pads connected to the gate line and the source line by the glass fiber as in the prior art. It is possible to prevent the phenomenon from occurring.

Meanwhile, in the dummy region, only one or more components and ball spacers may be formed without forming all the components formed in the active region as long as the active region and the cell gap of the two substrates can be kept the same.

After forming the components on both substrates, the two substrates 500 and 510 are bonded together and heated to cure the thermosetting seal material to bond the two substrates together.

Subsequently, as shown in FIG. 5B, a scribe line is cut to form a unit panel, and each unit panel is placed in a vacuum chamber to maintain the inside of the substrate in a vacuum state, and then immersed in a liquid crystal container to form a liquid crystal layer in the bonded substrate. A unit liquid crystal cell is formed.

As shown in FIGS. 6A and 6B, the column spacer 516 may be formed in place of the ball spacer as described above to maintain the cell gap in the active region and the dummy region.

In other words, instead of the process of randomly distributing the ball spacers to the lower substrate 500 as shown in FIGS. 6A and 6B, the column spacer 516 corresponds to the upper substrate corresponding to the wiring portion excluding the pixel region of the lower substrate 500. A pattern may be formed regularly in the active region and the dummy region of 510.

As described above, except that the column spacer 516 is formed instead of the ball spacer, the same process as the method of manufacturing the liquid crystal display device shown in FIGS. 5A and 5B is performed.

In this case, the column spacer 516 is formed of a photosensitive organic resin.

The manufacturing methods of the liquid crystal display device described above are based on a vacuum injection method, and the present invention may be formed by a liquid crystal drop method in addition to the vacuum injection method.

The liquid crystal dropping method is the same as the vacuum injection method for the lower substrate, the upper substrate preparation process, the spacer forming process, and the seal material applying process.

As described above, if the liquid crystal dropping method differs from the vacuum injection method, the liquid crystal layer is not injected in a vacuum state after the two substrates are bonded, but after the liquid crystal is dropped between the sealing materials formed on the lower substrate, the two substrates are bonded together. Is that.

As described above, in the liquid crystal dropping method, since the bonding process of both substrates is performed after the liquid crystal is dropped, when the thermosetting type sealing material is used as the sealing material, the liquid flows out while the sealing material is heated, and thus the liquid crystal is contaminated. UV (Ultra Violet) hardening type sealing material using an acrylic resin or the like is used as the sealing material.

Therefore, after the bonding process of both substrates, UV is irradiated to bond both substrates.

In the UV curable seal material is a mixture of a acrylate resin and a photocuring agent that becomes a radical when irradiated with UV at a predetermined ratio. The photocuring agent, which is irradiated with UV and becomes a radical, attacks the reaction site of the acrylate to form a polymer with another acrylate, and the formed polymer exhibits adhesion to the glass substrate.

The liquid crystal dropping method also forms a ball spacer or a column spacer in the dummy region to be cut out by cutting the scribe line, so that the cell gap between the active region and the seal member peripheral area is eliminated even when glass fibers are not mixed with the seal member formed in the active region. Can remain the same.

The manufacturing method of the liquid crystal display device of the present invention described above has the following effects.

First, by forming a spacer in the dummy region to be cut by the cutting process, the cell gap of the active region and the cell gap around the seal member can be kept the same without mixing glass fibers in the seal member.

As a result, the light transmittances around the active area and the seal material become the same, thereby making the overall screen brightness uniform.

Second, it is not necessary to mix and use the glass fiber in the seal material can save material costs.

Third, it is not necessary to mix and use the glass fiber in the seal material, it is possible to prevent the scratch phenomenon occurs in the metal pad due to the glass fiber.

Fourth, since spacers or other components may be formed in the dummy region of the upper substrate and the lower substrate simultaneously with the active region, the process may proceed without a separate process.

Claims (6)

In the method of manufacturing a liquid crystal display device having a lower substrate and an upper substrate in which an active region and a dummy region are defined based on a scribe line, Applying a sealing material to an edge of the active region of the upper substrate; Forming a spacer in the active region and the dummy region of the lower substrate or the upper substrate; And cutting the dummy area after the lower substrate and the upper substrate are bonded to each other. The method of claim 1, The seal material is a manufacturing method of the liquid crystal display device, characterized in that the glass fiber (glass fiber) is not mixed epoxy resin. The method of claim 1, The seal material is a method of manufacturing a liquid crystal display device, characterized in that the glass fiber (glass fiber) is not mixed acrylic resin. In the method of manufacturing a liquid crystal display device having a lower substrate and an upper substrate in which an active region and a dummy region are defined based on a scribe line, Sequentially forming a thin film transistor, a pixel electrode, and a first alignment layer on the lower substrate in which an active region and a dummy region are defined; Applying a sealing material to an edge of the active region of the upper substrate; Sequentially forming a black matrix, a color filter layer, a common electrode, and a second alignment layer on the upper substrate in which an active region and a dummy region are defined; And forming a spacer in the active region and the dummy region of the lower substrate or the upper substrate. The method of claim 4, wherein The spacer is a method of manufacturing a liquid crystal display device, characterized in that the ball spacer or column spacer. The method of claim 4, wherein The column spacer is a method of manufacturing a liquid crystal display device, characterized in that composed of a photosensitive organic resin.