KR20060110196A - Sealant for adhesion substrates, liquid crystal display device and fabricating method using the same - Google Patents

Abstract

A substrate bonding sealant, an LCD using the same, and a manufacturing method thereof are provided to allow the sealant to be stably and uniformly hardened by a UV diffusion effect of a scattering agent of the sealant, and thus to allow firm bonding between first and second substrates. A sealant includes a scattering agent(102) performing deffused reflection of an ultraviolet ray emitted from the outside. The scattering agent is made of inorganic or organic-based materials, has particles with diameters of 0.1~1.0m. The sealant further includes a ultraviolet-hardening resin, a photoinitiator, and a glass fiber.

Description

Sealant for bonding substrates and liquid crystal display device using same and manufacturing method therefor {sealant for adhesion substrates, Liquid Crystal Display device and fabricating method using the same}

1 is a plan view of a general liquid crystal display device.

2 is a cross-sectional view taken along line II-II of FIG. 1 for explaining a general seal pattern forming process.

3 is a schematic diagram of a sealant according to the present invention;

4 is an exploded perspective view of a liquid crystal display using a seal pattern according to the present invention.

5 is a cross-sectional view taken along line V-V of FIG. 4 for explaining a seal pattern forming process according to the present invention.

<Description of the symbols for the main parts of the drawings>

110: first substrate 112: data line

122: gate insulating film 124: protective film

130: second substrate 132: black matrix

134: common electrode 140: seal pattern

The present invention relates to a substrate bonding sealant and a liquid crystal display device using the same, and more particularly, when UV is irradiated to cure the seal pattern of the sealant formed between the first and second substrates, The present invention relates to a sealant capable of solving an uncured problem of a partial seal pattern due to an impermeable overlapping element formed thereon, and to a more stable liquid crystal display using the sealant.

In recent years, as the society enters the information age in earnest, the display field that visually expresses various electrical signal information has been rapidly developed. Flat display such as liquid crystal display device (LCD), plasma display panel device (PDP), field emission display device (FED), and electroluminescence display device (ELD) Flat Panel Display device (FPD) has been introduced to quickly replace the existing cathode ray tube (CRT).

The liquid crystal display has a high contrast ratio and is excellent in moving image display, and is currently being used most actively in the display screen, monitor, and TV field of the notebook, which uses the optical anisotropy and polarization property of the liquid crystal. Has

That is, as is well known, the liquid crystal has a thin and long molecular structure, optical anisotropy having an orientation in an array, and a polarization property in which the direction of molecular arrangement changes according to its size when placed in an electric field. A liquid crystal panel configured by bonding the first and second substrates each having a transparent field generating electrode formed thereon to face each other with the layers interposed therebetween, and a back light unit supplying light thereto. It comprises a, by generating the difference in transmittance by artificially adjusting the arrangement direction of the liquid crystal molecules by the electric field between the two field generating electrodes of the liquid crystal panel and expresses the difference in transmittance by passing the light emitted from the backlight unit to the outside .

Recently, the active matrix type, which defines pixels as the basic unit of image expression on a liquid crystal panel and controls each pixel independently using a thin film transistor (TFT), has a color. It is widely used for reproducibility and video display.

Meanwhile, in the liquid crystal display device, a seal pattern made of a sealant is used to prevent leakage of the liquid crystal layer interposed between the first and second substrates and to maintain a bonding state. FIG. 1 is a schematic view of a general liquid crystal panel. Top view.

As shown, a plurality of data lines 12 and gate lines 16 vertically cross each other on one surface of the first substrate 10 having a relatively large size in the liquid crystal panel 2 to define a pixel P having a matrix form. The thin film transistor T is provided at an intersection thereof and is connected in a one-to-one correspondence with the transparent pixel electrode 20 mounted in each pixel P. At this time, at least one end of the data line 12 and the gate line 16 extends to the edge of the first substrate 10 to form a data pad 14 and a gate pad 18 to which an external driving circuit can be connected. .

Next, the second substrate 30 having a relatively smaller size than the first substrate 10 and exposing the data pad 14 and the gate pad 18 has a liquid crystal layer interposed therebetween. Although not clearly shown in the drawing, the second substrate 30 covers the non-display elements such as the thin film transistor T, including the data line 12 and the gate line 16, and hides the pixels. A grid-like black martix that exposes only the electrode 20, and red, green, and blue color filters filled in each of these grids A covering transparent common electrode is provided.

A sealant seal 40 of sealant is formed between the first and second substrates 10 and 30 to correspond to the edge of the second substrate 30 to form a close adhesion between the substrates 10 and 30 and a liquid crystal layer. To prevent leakage.

On the other hand, the sealant constituting the general seal pattern 40 may be classified into a thermosetting resin cured largely by heating and an ultraviolet curable resin cured by ultraviolet rays, but at present, an ultraviolet curable resin exhibiting improved adhesion in a low temperature process is used. Widely used, glass fiber for cell gap retention function is included in a monomer containing a photoinitiator and a UV curing agent, and forms a fluid gel state.

Therefore, after forming the seal pattern 40 on any one substrate (10 or 30) by dispensing or screen printing method, it is cured and bonded by irradiating external UV while pressing both substrates (10,30). In this case, the UV is usually irradiated from the side of the first substrate 10 having less light blocking elements such as black matrices.

However, in this process, the UV radiation irradiated to the part of the seal pattern 40 is blocked by the data line 12 or the gate line 16 formed on the first substrate 10, so that the part is not cured. It is not possible.

Referring to FIG. 2, which is a cross-sectional view taken along the line II-II of FIG. 1, a plurality of gate lines 16 pass through one surface of the first substrate 10 in the seal pattern region, and a gate line () is formed on the upper surface thereof. A protective film 24 for protecting a thin film transistor (see T in FIG. 1) is covered, as well as a gate insulating film 22 for interlayer insulation between the data line 16 and the data line (see 16 in FIG. 1). In addition, the seal pattern 40 is formed on the passivation layer 24 to cross the gate line 16, and UV is blocked in some sections by the gate line 16 made of an opaque metal material. In this case, reference numerals 32 and 44 denote black matrices and a common electrode provided on the second substrate, respectively.

As a result, a phenomenon in which the seal pattern 40 of the part shielded by the gate line 16 may not be cured is generated. As a result, the bonding state of the two substrates 10 and 30 may not be maintained closely. There is a problem in which the unsealed sealant may be contaminated with the liquid crystal layer.

Accordingly, the present invention has been made to solve the above problems, the sealant which can solve the uncured problem of the partial seal pattern due to the impermeable overlapping element and the liquid crystal display device to maintain a more stable bonding state using the same The purpose is to provide.

In order to achieve the above object, the present invention provides a liquid crystal display device including first and second substrates facing each other with a liquid crystal layer interposed therebetween to prevent leakage of the liquid crystal layer and to bond the first and second substrates together. As a sealant for making a sealant, a sealant including a scattering agent which diffusely reflects UV irradiated from the outside is provided.

In this case, the scattering agent is an inorganic or organic ultraviolet scattering material, characterized in that it comprises a fine particle of 0.1 ~ 1.0μm diameter contained in a few% to 20%, the sealant is a UV curable resin; Photoinitiator; It further comprises a glass fiber.

In addition, the present invention provides a liquid crystal display device using the sealant, comprising: a liquid crystal panel including the first and second substrates bonded to each other by a seal pattern of the sealant with the liquid crystal layer interposed therebetween; Provided is a liquid crystal display device including a backlight provided on the rear surface of the liquid crystal panel.

A gate line and a data line intersecting each other to define a plurality of pixels on a first substrate facing surface facing the second substrate; A thin film transistor provided at an intersection point of the gate line and the data line; A lattice-shaped black matrix connected to the thin film transistor and including a transparent pixel electrode mounted on each pixel, the lattice-shaped black matrix exposing only the pixel electrode on the opposite surface of the second substrate facing the first substrate; A color filter filled in the grid; And a transparent common electrode covering the black matrix and the color filter.

In another aspect, the present invention provides a method of manufacturing a liquid crystal display device comprising the steps of: a) providing the first and second substrates; b) forming a seal pattern of the sealant corresponding to an edge of the second substrate; c) pressing the first and second substrates using the seal pattern; and d) irradiating the UV on the seal pattern outside the first substrate to cure the seal pattern.

In this case, after step b) and before step c), the method may further include interposing a liquid crystal layer between the first and second substrates, or after the step d), the liquid crystal between the first and second substrates. Injecting the layer may be further included.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

3 is a schematic view of the sealant 100 according to the present invention, and includes a UV curable resin, a photoinitiator, and a scattering agent 102 as a main component of a fluid gel state having a predetermined adhesive force.

In this case, the UV curable resin may be an acrylic resin, and the photoinitiator serves to cure the UV curable resin through external UV. In addition, the scattering agent 102 serves to diffuse evenly within the sealant 100 by diffusely reflecting the external UV, and may be composed of fine particles having high reflectivity of light, for example, zinc oxide as an inorganic UV scattering material. Titanium dioxide, gaolin, calcium carbonate, mica, etc. may be used, and an organic material of a polymer synthetic resin may be used, and the size thereof is 1/2 of an ultraviolet wavelength (λ = 290 to 400 nm => 0.29 to 0.4 μm, λ / 2 => 0.15 ~ 0.2μm), 0.1 ~ 1.0μm is possible to show the maximum reflectance.

In addition, such a scattering agent may be blended during the polymerization of the sealant. Preferably, the particles are small in size, but when the particles are too fine and excessively contained, the surface energy may increase and re-aggregate. It may contain about 20%.

That is, the biggest feature of the sealant 100 according to the present invention is that it contains a scattering agent 102 that diffuses diffusely evenly by the external UV, it can have the same components as the other UV-curable sealant It is also possible to contain glass fibers for cell gap maintenance. In addition, the sealant 100 according to the present invention may include an epoxy-based thermosetting resin, if necessary.

Since the sealant 100 according to the present invention contains the scattering agent 102, it is possible to evenly diffuse the external UV in the interior, thereby obtaining a faster curing effect even with a small amount of light.

The sealant 100 according to the present invention may be mobilized to the bonding of the first and second substrates for the liquid crystal display device in the form of a seal pattern, the accompanying Figure 4 is a seal pattern of the sealant 100 according to the present invention An exploded perspective view of the liquid crystal display device using 140.

As can be seen, the LCD according to the present invention includes a liquid crystal panel 106 composed of first and second substrates 110 and 130 bonded to each other with the liquid crystal layer 150 interposed therebetween, and a backlight for supplying light from the rear surface thereof. 200.

First, as the liquid crystal panel 106, a plurality of data lines 112 and gate lines 116 vertically cross each other on one surface of the first substrate 110, which is called a lower substrate or an array substrate. The thin film transistor T is provided at an intersection thereof and is connected one-to-one with the transparent pixel electrode 120 provided in each pixel P. At this time, at least one end of the data line 112 and the gate line 116 respectively extend to the edge of the first substrate 110 to form a pad portion to which an external driving circuit can be connected. Only the data pad 114 appears in the drawing. have.

The thin film transistor T includes a source electrode connected to the data line 112, a drain electrode connected to the pixel electrode 120, a gate electrode connected to the gate line 116, and a semiconductor layer serving as a conductive channel.

In addition, the second substrate 130 facing the substrate is called an upper substrate or a color filter substrate, and on one surface thereof, a data line 112, a gate line 116, and a thin film transistor T of the first substrate 110. A black matrix 132 having a lattice bordering the pixel region P so as to expose only the pixel electrode 120 while covering a non-display element such as), and sequentially corresponding to each pixel P in the lattice. An example of repeated arrangement includes R (rea), G (green), and B (blue) color filters 133a, 133b, and 133c and a transparent common electrode 134 covering all of them. Since the second substrate 130 has a smaller size than the first substrate 110, the second substrate 130 exposes the data 114 and the gate pad of the first substrate 110 to the outside during face-to-face bonding.

Although not clearly shown in the drawings, upper and lower alignment layers for determining the initial molecular alignment direction of the liquid crystal are interposed between the two substrates 110 and 130 and the liquid crystal layer 150. At least one outer surface of the 110 and 130 may be a polarizing plate for selectively transmitting only a specific polarization.

And a second substrate having a relatively small size relative to any substrate 110 or 130 to prevent leakage of the liquid crystal layer 150 interposed between the first and second substrates 110 and 130 and to maintain a tightly bonded state. A seal pattern 140 made of a sealant according to the present invention is formed to correspond to the edge of the 130, and both substrates 110 and 130 are bonded to each other by using the sealant, and the bonding process is as follows.

First, a seal pattern 140 having first and second substrates 110 and 130 completed through separate processes, and corresponding to an edge of the second substrate 130 on one surface of the first or second substrate 110 or 130. ) Is formed. In this case, the material used is a sealant according to the present invention (see 100 of FIG. 3), and a screen printing or dispensing method may be employed.

Next, after the liquid crystal layer 150 is dropped, both of the substrates 110 and 130 are compressed or the liquid crystal layer 150 is injected therebetween using the vacuum after the compression of the substrates 110 and 130. In this case, a liquid crystal injection hole may be formed in a part of the seal pattern 140 of the sealant according to the present invention, and the liquid crystal injection hole may be sealed after bonding.

In the compressed state of the first and second substrates 110 and 130, UV is irradiated from the outer surface of the first substrate 110 to cure the seal pattern 140, and thus the UV irradiation direction is outside the first substrate 110. The reason is to reduce the possibility of shading by the black matrix 132.

As the seal pattern 140 is cured by the UV irradiation, both substrates 110 and 130 are closely bonded to each other, and a process of heating a corresponding part after UV irradiation may be added as necessary.

On the other hand, using the sealant seal pattern 140 of the sealant according to the present invention in the above-described process, it is possible to improve the curing rate by UV irradiation, as well as more uniform curing, which is cut along the VV line of FIG. A cross-sectional view of FIG. 5 will be described with reference.

As shown, the gate insulating layer 122 for electrically insulating the data line 112 and the gate line 116 is covered on one surface of the first substrate 110 in the seal pattern region, and the data line 112 passes through the upper portion thereof. The protective layer 124 for protecting the thin film transistor T is covered. In this case, an alignment film or the like may be formed on the protective layer 124.

The seal pattern 140 according to the present invention passes through the data line 112 to the upper portion thereof.

In addition, a black matrix 132 is formed on one surface of the second substrate 130 facing the same, and the transparent common electrode 134 covers the black matrix 132. In this case, a separate alignment layer covering the transparent common electrode 134 may be present.

In addition, the seal pattern 140 according to the present invention crosses the data line 112 while connecting the first and second substrates 110 and 130.

Meanwhile, after forming the seal pattern 140 according to the present invention, the UV is irradiated from the outside of the first substrate 110 in a state in which the first and second substrates 110 and 130 are press-bonded with the liquid crystal layer interposed therebetween. A part is blocked by the data line 112 during the process of reaching the seal pattern 140 according to the present invention. However, the seal pattern 140 made of the sealant according to the present invention (see 100 in FIG. 3) is diffusely scattered by UV reflection. Since the scattering agent 102 is contained, the sealant overlapping the upper portion of the data line is uniformly cured in a short time despite the impermeable light blocking element such as the data line 112.

In this case, the density of the scattering agent (see 102 of FIG. 3) contained in the sealant (see 100 of FIG. 3) according to the present invention may be freely adjusted according to the diffuse reflection condition of the scattering agent 102 including UV intensity. The type of scattering agent 102 can also be used without any limitation as long as it causes diffuse reflection of light. In addition, although the above description shows a case in which the seal pattern 140 is blocked by the data line 112, the same is true at the intersection with the gate line 116.

Therefore, the sealant according to the present invention is capable of stable and uniform curing in spite of other overlapping elements blocking the seal pattern of the sealant due to the UV diffusion effect of the scattering agent, and thus the tight adhesion of the first and second substrates. There is an advantage to this.

Claims (8)

A liquid crystal display device comprising a first and a second substrate facing each other with a liquid crystal layer interposed therebetween, as a sealant for preventing leakage of the liquid crystal layer and bonding the first and second substrates to each other. A sealant comprising a scattering agent that diffusely reflects UV emitted from the outside. The method of claim 1, The scattering agent is an inorganic or organic ultraviolet scattering material, and comprises a sealant containing a few% to 20% of the fine particles having a diameter of 0.1 ~ 1.0μm. The method of claim 1, The sealant is UV curable resin; Photoinitiator; Sealant further comprising glass fibers. A liquid crystal display device using a sealant according to any one of claims 1 to 3, wherein A liquid crystal panel including the first and second substrates bonded to each other by the seal pattern of the sealant with the liquid crystal layer interposed therebetween; And a backlight disposed on the rear surface of the liquid crystal panel. The method of claim 4, wherein A gate line and a data line intersecting each other to define a plurality of pixels on a first substrate opposing surface facing the second substrate; A thin film transistor provided at an intersection point of the gate line and the data line; A transparent pixel electrode connected to the thin film transistor and mounted on each pixel; A lattice-shaped black matrix exposing only the pixel electrode on a surface facing the second substrate, the surface facing the first substrate; A color filter filled in the grid; A transparent common electrode covering the black matrix and the color filter Included liquid crystal display device. A method of manufacturing a liquid crystal display device according to claim 5, a) providing said first and second substrates; b) forming a seal pattern of the sealant corresponding to an edge of the second substrate; c) pressing the first and second substrates using the seal pattern; d) hardening by irradiating said UV with said seal pattern outside said first substrate Method of manufacturing a liquid crystal display device comprising a. The method of claim 6, And after step b) and before step c), interposing a liquid crystal layer between the first and second substrates. The method of claim 6, And injecting the liquid crystal layer between the first and second substrates after step d).

Images