KR20060058422A - Liquid crystal display - Google Patents

Abstract

A liquid crystal display device capable of improving the adhesion between a color filter substrate and a TFT substrate is provided. The liquid crystal display device includes a color filter substrate including a common electrode and a color filter, a TFT substrate disposed to face the color filter substrate, the TFT substrate including a thin film transistor array and a pixel electrode, and interposed at edges of the color filter substrate and the TFT substrate. The color filter substrate and the TFT substrate are coupled to each other, and a seal line having an upper end in direct contact with a common electrode of the color filter substrate and a conductive film formed on the TFT substrate in direct contact with a lower end of the seal line.

LCD, seal line, seal line, ITO

Description

Liquid crystal display

1 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

10: front cover 11: rear cover

20: chassis 30: liquid crystal display panel assembly

31: gate tape carrier package 32: data tape carrier package

33: TFT substrate 34: color filter substrate

35: integrated printed circuit board 40: backlight unit

41: optical sheets 42: light guide plate

43: lamp assembly 44: reflector

45: mold frame 100: liquid crystal display device

110: upper substrate 112: black matrix

114: color filter 116: common electrode

120: polarizer 130: liquid crystal layer                 

132: seal line 140: polarizer

150: lower substrate 152: gate electrode

154: gate insulating film 156: active layer

158: source electrode 160: drain electrode

162: protective film 164: pixel electrode

264, 364: conductive film

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of improving adhesion between a color filter substrate and a TFT substrate constituting a liquid crystal display panel assembly.

Cathode ray tube (CRT), which is one of the display devices that are generally used, is mainly used for monitors such as televisions, measuring devices, information terminal devices, etc., but due to its own weight and size, It could not actively respond to the demand for miniaturization and weight reduction.

In order to replace the cathode ray tube, it has advantages such as small size, light weight, low power consumption, and the like, and a liquid crystal display device that displays information by using the electrical and optical properties of the liquid crystal injected into the liquid crystal panel has been actively developed. Recently, it plays a role as a flat panel display device. In general, a liquid crystal display device is a display device having low power consumption, light weight, and small volume. The liquid crystal display device has been widely applied to a wide range of industries, for example, the computer industry, the electronics industry, and the information and communication industry due to such unique advantages. As a matter of fact, the liquid crystal display device having such advantages has been applied to various fields such as a display device of a portable computer, a monitor of a desktop computer, a monitor of a high-definition video device, and the like.

The liquid crystal display is divided into TN (Twisted Nematic) and STN (Super-Twisted Nematic) methods, and the difference between the driving methods is the active matrix display method using the switching element and the TN liquid crystal and the passive matrix using the STN liquid crystal. There is a passive matrix display method.

The big difference between these two methods is that the active matrix display method is used for TFT-LCD, which drives the LCD using the TFT as a switch, and the passive matrix display method does not use transistors, thus requiring a complicated circuit. Do not LCDs using TFTs are widely used in recent years with the spread of portable computers.

The liquid crystal display device includes a color filter substrate including a color filter and a TFT substrate including a thin film transistor array. The color filter substrate and the TFT substrate face each other and are bonded to each other by a seal line interposed between the two substrates, and a liquid crystal layer is formed in a constant gap formed therebetween. As described above, the liquid crystal display device is composed of two substrates (color filter substrate and TFT substrate) on which electrodes are formed and a liquid crystal layer interposed therebetween. The liquid crystal molecules of the liquid crystal layer are rearranged by applying a voltage to the electrode. It is a device configured to display a predetermined image by adjusting the amount of light transmitted.

Reflecting the recent trend for ultra-slim liquid crystal display devices, the line width of the seal line joining the color filter substrate and the TFT substrate is also decreasing. As such, the line width of the seal line is reduced, but the adhesion force must be maintained in order to prevent separation between the color filter substrate and the TFT substrate. However, while the size of the panel of the liquid crystal display device increases, the line width of the seal line joining the two substrates decreases, causing a problem that the two substrates are easily separated.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a liquid crystal display device capable of improving adhesion between a color filter substrate and a TFT substrate.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, a liquid crystal display device includes a color filter substrate including a common electrode and a color filter, and a thin film transistor array and a pixel electrode disposed to face the color filter substrate. A TFT substrate, a seal line interposed between edges of the color filter substrate and the TFT substrate to couple the color filter substrate and the TFT substrate, and a top end of which is in direct contact with the common electrode of the color filter substrate; And a conductive film formed on the TFT substrate in direct contact with the bottom of the seal line.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3.

1 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the liquid crystal display device 100 according to an exemplary embodiment of the present invention generally has a liquid crystal display panel assembly 30, a backlight unit 40, a chassis 20, a front cover 10, and a rear cover. And (11).

Here, the liquid crystal display panel assembly 30 includes a TFT substrate 33, a liquid crystal display panel including a color filter substrate 34, a liquid crystal (not shown), a gate tape carrier package 31, and a data tape carrier package 32. And an integrated printed circuit board 35.                     

The liquid crystal display panel includes a TFT substrate 33 including a gate line (not shown) and a data line (not shown), a thin film transistor array, a pixel electrode, and the like, and a TFT substrate 33 disposed above the TFT substrate 33. It includes a color filter substrate 34 installed to face.

The gate tape carrier package 31 is connected to each gate line formed on the TFT substrate 33, and the data tape carrier package 32 is connected to each data line (not shown) formed on the TFT substrate 33.

Meanwhile, the integrated printed circuit board 35 may process both the gate driving signal and the data driving signal so that the gate driving signal can be input to the gate tape carrier package 31 and the data driving signal can be input to the data tape carrier package 32. Several moving parts are mounted.

Referring to FIG. 1, a backlight unit 40 according to an embodiment of the present invention may include optical sheets 41, a light guide plate 42, a lamp assembly 43, a reflective plate 44, a mold frame 45, and the like. It is composed.

Here, the light guide plate 42 serves to guide the light supplied to the liquid crystal display panel assembly 30. The lamp assembly 43 is inserted into the side of the light guide plate 42 to emit this light.

The reflective plate 44 is installed on the lower surface of the light guide plate 42 to reflect the light emitted to the lower portion of the light guide plate 42 to the top. The optical sheets 41 are installed on the upper surface of the light guide plate 42 to diffuse and collect light transmitted from the light guide plate 42. The mold frame 45 stores and fixes the components of the backlight unit 40. Here, in the case of the small liquid crystal display device 100, one lamp is usually installed on the side of the light guide plate 42, but as the liquid crystal display device 100 becomes larger, one lamp assembly 43 is provided to obtain sufficient luminance. A plurality of lamps can be installed.

Hereinafter, the color filter substrate 34 and the TFT substrate 33 constituting the liquid crystal display device 100 of the present invention will be described in detail with reference to FIG. 2. 2 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a liquid crystal display according to an exemplary embodiment of the present invention includes a color filter substrate 34, a TFT filter 33, and a color filter substrate provided opposite to the TFT substrate 33 and the TFT substrate 33. It consists of a liquid crystal layer 130 interposed between 34.

Here, the TFT substrate 33 is a substrate provided with a plurality of thin film transistor arrays and pixel electrodes 164 on the lower substrate 150 of an insulating material. The thin film transistor array includes a gate electrode 152, a source electrode 158, a drain electrode 160, and the like formed on the lower substrate 150. As the gate electrode 152, the source electrode 158, and the drain electrode 160, a conductive film such as aluminum (Al), chromium (Cr), or molybdenum tungsten (MoW) may be used.

A passivation layer 162 having a contact hole for exposing the drain electrode 160 is formed on the thin film transistor array. The passivation layer 162 may be formed of an organic insulating layer. Specifically, the passivation layer 162 may be formed of a photosensitive insulating material made of acrylic resin.

On the passivation layer 162, the pixel electrode 164 electrically contacting the drain electrode 160 through the contact hole is stacked to have a uniform thickness. The pixel electrode 164 is made of indium tin oxide (ITO) or indium zinc oxide (IZO), which is a transparent conductive material. As shown in FIG. 2, a conductive film 264 is formed in a region corresponding to the lower end of the seal line 132 formed at the edge of the TFT substrate 33. The conductive film 264 increases the adhesion between the seal line 132 and the TFT substrate 33. This will be described later. In order to simplify the process, the conductive layer 264 may use a material such as the pixel electrode 164. That is, while forming the pixel electrode 164 on the passivation layer 162, the conductive layer 264 made of ITO may be formed in the region corresponding to the lower end of the seal line 132.

An orientation layer (not shown) is stacked on the pixel electrode 164. As the alignment layer, an organic polyimide series may be mainly used. Unexplained reference numeral 154 is a gate insulating film, reference numeral 156 is an active layer, and reference numeral 140 is a polarizing plate.

The color filter substrate 34 is a substrate including a black matrix 112, a color filter 114, and a common electrode 116 on the upper substrate 110.

In detail, the color filter 114 including R (Red), G (Green), and B (Blue) is provided on the upper substrate 110. In addition, the black matrix 112 is formed at a position opposite to the thin film transistor array to absorb diffusely reflected light. The common electrode 116 is stacked on the color filter 114 with a uniform thickness. Here, the common electrode 116 is made of ITO or IZO, which is a transparent conductive material.                     

An alignment film (not shown) is stacked on the common electrode 116. Liquid crystal molecules in the liquid crystal layer 130 interposed between the TFT substrate 33 and the color filter substrate 34 by an alignment film (not shown) formed on the TFT substrate 33 and the color filter substrate 34 are selected at an angle. Pretilt. Unexplained reference numeral 120 denotes a polarizing plate.

As shown in FIG. 2, a seal line 132 is formed at the edge coupling portion of the TFT substrate 33 and the color filter substrate 34. The seal line 132 forms a gap for liquid crystal injection between the TFT substrate 33 and the color filter substrate 34 and prevents the injected liquid crystals from leaking. The seal line 132 is formed of a thermosetting epoxy resin and the like in a desired pattern.

The seal line 132 is in contact with the common electrode 116 formed on the color filter substrate 34, and has good adhesion between the conductive material used as the common electrode 116 and the epoxy resin used as the seal line 132. In particular, since the adhesion between the transparent conductive material ITO, which is the main material of the common electrode 116, and the thermosetting epoxy resin, which is the main material of the seal line 132, is very good, the line width of the seal line 132 and the color filter are reduced even though the line width of the seal line 132 is reduced. Separation does not occur well between the substrates 34.

In addition, as mentioned above, the seal line 132 contacts the conductive film 264 formed on the protective film 162 of the TFT substrate 33 to bond with the TFT substrate 33. A conductive film 264 is interposed between the protective film 162 and the seal line 132 to reinforce the bonding force between the 162 and the seal line 132. Adhesive force is good between the conductive material used for the conductive film 264 and the epoxy resin used for the protective film 162. In particular, the conductive film 264 using ITO as a main material has a good bonding force with the protective film 162 made of an organic material, and the conductive film 264 has a bonding force with the seal line 132 mainly containing an epoxy resin. Therefore, even if the line width of the seal line 132 is reduced, separation does not occur well between the seal line 132 and the TFT substrate 33.

Hereinafter, a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention will be described with reference to FIG. 2.

Referring to the method of forming the TFT substrate 33, after depositing a metal film such as aluminum (Al), chromium (Cr) or molybdenum tungsten (MoW) on the lower substrate 150 made of an insulating material such as glass or ceramic The metal film is patterned to form a gate line (not shown) and a gate electrode 152 branching from the gate line. Subsequently, silicon nitride is deposited on the entire surface of the lower substrate 150 including the gate electrode 152 to form a gate insulating layer 154.

After the amorphous silicon film is formed on the gate insulating film 154, the active layer 156 is formed on the gate insulating film 154 over the gate electrode 152 by patterning.

Subsequently, a metal film such as aluminum (Al), chromium (Cr) or molybdenum tungsten (MoW) is deposited on the entire surface of the resultant, and then the metal film is patterned to orthogonal to the gate line (not shown), The source electrode 158 and the drain electrode 160 branching from the data line are formed. Accordingly, the thin film transistor array including the gate electrode 152, the active layer 156, the source electrode 158, and the drain electrode 160 is completed. In this case, a gate insulating layer 154 is interposed between the gate line and the data line to prevent the gate line from contacting the data line.

Subsequently, a resist is applied to the entire surface of the lower substrate 150 on which the thin film transistor array is formed to have a thickness of about 1 to 3 μm to form a protective film 162 of an organic material. A contact hole for partially exposing the drain electrode 160 is formed on the passivation layer 162 through a photo / etch process.

After depositing a metal film, for example, a reflective conductive film or a transparent conductive film or a metal film on which the reflective conductive film and the transparent conductive film are stacked, the metal film is patterned into a predetermined pixel shape on the protective film 162 to form the pixel electrode 164. To form. Then, the conductive film 264 is formed at the portion where the seal line 132 at the edge of the TFT substrate 33 is joined. The conductive film 264 may be formed in the same process as the pixel electrode 164 or may be formed through a separate process. In order to simplify the process, when the pixel electrode 164 and the conductive film 264 are formed in the same process, the conductive film 264 is made of the same material as that of the pixel electrode 164.

Subsequently, an alignment film (not shown) is formed on the pixel electrode 164 to apply a resist and to pretilt the liquid crystal molecules in the liquid crystal layer at a selected angle through a rubbing process or the like. The alignment layer should be deposited to a uniform thickness on the lower substrate 150, and rubbing should also be uniform. In addition, rubbing is a main process of determining the initial alignment direction of the liquid crystal. The rubbing of the alignment layer enables normal driving of the liquid crystal and has uniform display characteristics. Such alignment layers are mainly used in organic polyimide series.                     

By performing the above process, the TFT substrate 33 including the gate electrode 152, the gate insulating film 154, the active layer 156, the source electrode 158, and the drain electrode 160 is completed.

In addition, the color filter substrate 34 including the elements may be formed by forming the color filter 114, the common electrode 116, and the alignment layer on the upper substrate 110 formed of the same material as the lower substrate 150. ).

Next, the thermosetting seal line 132 is interposed at the edge of the TFT substrate 33. The region where the seal line 132 is formed is a region in the TFT substrate 33 that does not include the thin film transistor array.

The thermosetting seal line 132 is a material that can bond the two objects by applying heat. However, the seal line 132 of the present invention may include not only a thermosetting resin but also a photocurable resin, but will be described based on the thermosetting resin.

The TFT substrate 33 coated with the seal line 132 and the color filter substrate 34 are disposed to face each other, and the two substrates are bonded while applying heat.

Subsequently, in a state where the color filter substrate 34 and the TFT substrate 33 are bonded together, a liquid crystal material is injected into a space between the color filter substrate 34 and the TFT substrate 33 to form the liquid crystal layer 130. Complete the display device.

The forming of the liquid crystal layer 130 may be performed by arranging the color filter substrate 34 and the TFT substrate 33 so as to face each other before bonding the color filter substrate 34 and the TFT substrate 33 to each other. It can also be done.

In this way, when the color filter substrate 34 and the TFT substrate 33 are bonded to each other to complete the liquid crystal display device, the conductive film 264 is interposed between the two substrates and the seal line 132. And the adhesive force with the seal line 132 can be improved. Therefore, even if the line width of the seal line 132 is reduced, separation can be prevented from occurring between the seal line 132 and the TFT substrate 33.

Hereinafter, another embodiment of the present invention will be described with reference to FIG. 3. For convenience of description, members having the same functions as the members shown in the drawings of the previous embodiment are denoted by the same reference numerals, and therefore description thereof is omitted. As shown in Fig. 3, the liquid crystal display of this embodiment has a structure basically the same as the liquid crystal display of the previous embodiment except for the following. That is, as shown in FIG. 3, the conductive film 364 interposed between the lower end of the seal line 132 and the TFT substrate 33 is disposed at the lower end of the inner wall of the seal line 132. That is, when the conductive film 364 is formed by passing through the lower end of the outer wall of the seal line 132 and being exposed to the outside of the liquid crystal display device, there is a possibility that a short circuit occurs with the common electrode 116 formed on the color filter substrate 34. Therefore, it is more preferable that the conductive film 364 overlaps with the lower end of the inner wall of the seal line 132.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

 As described above, according to the liquid crystal display device according to the present invention, it is possible to provide a liquid crystal display device excellent in reliability by improving the adhesion between the color filter substrate and the TFT substrate.

Claims (4)

A color filter substrate including a common electrode and a color filter; A TFT substrate disposed to face the color filter substrate and including a thin film transistor array and a pixel electrode; A seal line interposed at edges of the color filter substrate and the TFT substrate to couple the color filter substrate and the TFT substrate, the seal line having an upper end thereof in direct contact with the common electrode of the color filter substrate; And And a conductive film in direct contact with a lower end of the seal line and formed on the TFT substrate. According to claim 1, And the conductive layer is made of the same material as that of the pixel electrode. The method of claim 2, And the conductive film overlaps a portion of a lower end of an inner wall of the seal line. The method according to any one of claims 1 to 3, And the conductive film is made of ITO.

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