KR100743418B1 - Array substrate for liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an array substrate for a liquid crystal display device and a method of manufacturing the same.

In the liquid crystal display, defects due to misalignment may occur when the color filter substrate and the array substrate are bonded together, and the aperture ratio is reduced when the black matrix is widely formed in consideration of the bonding margin. In addition, when the color filter is formed by a pigment dispersion method or a printing method, the process is complicated, and the consumption of materials is large.

In the present invention, the color filter can be formed on the array substrate to prevent misalignment and improve the aperture ratio, and when the color filter is formed, a barrier pattern is formed on a portion other than the pixel electrode, and then electrodeposited on the pixel electrode. The manufacturing cost can be reduced by reducing the consumption of processes and materials while preventing the damage.

Color filter, electrodeposition, array board

Description

Array substrate for liquid crystal display device and manufacturing method thereof             

1 is a cross-sectional view of a general liquid crystal display device.

2 is a plan view of an array substrate for a liquid crystal display device according to the present invention;

3 is a cross-sectional view taken along line III-III of FIG. 2.

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

5A to 5F are cross-sectional views illustrating a process of manufacturing an array substrate for a liquid crystal display according to the present invention.

The present invention relates to an array substrate for a liquid crystal display device and a manufacturing method thereof, and more particularly, to an array substrate including a color filter and a manufacturing method thereof.

Recently, with the rapid development of the information society, there is a need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption. Among them, a liquid crystal display having excellent color reproducibility, etc. displays are actively being developed.

In general, a liquid crystal display device arranges two substrates on which electrodes are formed so that the surfaces on which the two electrodes are formed face each other, injects a liquid crystal material between the two substrates, and applies a voltage to the two electrodes to generate an electric field. By moving the liquid crystal molecules, the device expresses the image by the transmittance of light that varies accordingly.

The lower substrate of the liquid crystal display is formed by repeating a process of forming a thin film and photolithography with an array substrate including a thin film transistor for applying a signal to a pixel electrode. The upper substrate is a substrate including a color filter. Three colors of red (R), green (G) and blue (B) are sequentially arranged, and are produced by methods such as pigment dispersion, dyeing, and electrodeposition.

Hereinafter, a structure of a general liquid crystal display device will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a general liquid crystal display.

As shown in FIG. 1, a gate electrode 21 made of a conductive material such as a metal is formed on a transparent first substrate 10, and a silicon nitride film (SiN _x ) or a silicon oxide film (SiO ₂ ) is formed thereon. The gate insulating film 30 covers the gate electrode 21. An active layer 41 made of amorphous silicon is formed on the gate insulating layer 30 on the gate electrode 21, and ohmic contact layers 51 and 52 made of amorphous silicon doped with impurities are formed thereon. .

Source and drain electrodes 61 and 62 made of a conductive material such as a metal are formed on the ohmic contact layers 51 and 52, and the source and drain electrodes 61 and 62 together with the gate electrode 21 are thin film transistors. (T).

Although not shown, the gate electrode 21 is connected to the gate wiring, the source electrode 61 is connected to the data wiring, and the gate wiring and the data wiring are orthogonal to each other to define the pixel region.

Subsequently, a passivation layer 70 made of a silicon nitride film, a silicon oxide film, or an organic insulating layer is formed on the source and drain electrodes 61 and 62, and the passivation layer 70 has a contact hole 71 exposing the drain electrode 62. Has

A pixel electrode 81 made of a transparent conductive material is formed in the pixel area above the passivation layer 70, and the pixel electrode 81 is connected to the drain electrode 62 through the contact hole 71.

On the other hand, the second substrate 110 is spaced apart from the first substrate 10 at regular intervals on the first substrate 10, and the black matrix 121 is disposed on the inner surface of the second substrate 110. ) Is formed at a position corresponding to the thin film transistor T. Although not illustrated, the black matrix 121 covers portions other than the pixel electrode 81. A color filter 131 is formed below the black matrix 121. The color filters 131 sequentially repeat red, green, and blue colors, and one color corresponds to one pixel area. The common electrode 141 made of a transparent conductive material is formed under the color filter 131.

The liquid crystal layer 150 is injected between the two substrates 10 and 110.

The liquid crystal display is formed through a process of forming an array substrate and a color filter substrate, and arranging the lower pixel electrode and the upper color filter in a one-to-one correspondence. In the process of disposing the substrate, misalignment occurs. Defects such as light leakage can occur. In order to prevent this, the width of the black matrix of the upper substrate may be widened. In this case, the aperture ratio of the liquid crystal display becomes low.

On the other hand, the color filter is prepared by the pigment dispersion method, dyeing method, electrodeposition method and the like as mentioned above. Among them, the dyeing method and the pigment dispersing method produce a color filter by applying a chlorinated photosensitive film or a coloring photosensitive film, and then exposing and developing the color filter. Repeat three times. Therefore, it takes a long time to manufacture the color filter, and the film is applied to and removed from the entire surface of the substrate, thus increasing the consumption of materials.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an array substrate for a liquid crystal display device having a high aperture ratio and a method of manufacturing the same.

Another object of the present invention is to provide a method for producing a color filter with a simple process and low material consumption, and a color filter manufactured by the method.

In the array substrate for a liquid crystal display device according to the present invention for achieving the above object, a gate wiring and a data wiring orthogonal to each other are formed on the substrate, and a thin film transistor electrically connected to the gate wiring and the data wiring is formed. . The gate wiring, the data wiring, and the thin film transistor are covered with a protective film, and a pixel electrode connected to the thin film transistor is formed on the protective film. A barrier pattern having an opening that exposes the pixel electrode is formed on the pixel electrode, and a color filter of red, green, and blue is electrodeposited on the pixel electrode. An overcoat layer is formed on the barrier pattern and the color filter.

Here, the barrier pattern may be made of an organic material, and may be made of either benzocyclobutyne (BCB) or black resin.

On the other hand, in the method for manufacturing an array substrate for a liquid crystal display device according to the present invention, a substrate is provided, and a thin film transistor connected to the gate wiring and the data wiring and the gate wiring and the data wiring is orthogonal to the substrate. Next, a passivation layer is formed on the gate line, the data line, and the thin film transistor, and a pixel electrode positioned on the passivation layer and connected to the thin film transistor is formed. Subsequently, after forming a barrier pattern having an opening exposing the pixel electrode on the pixel electrode, the color filter is electrodeposited on the pixel electrode exposed through the opening. Next, an overcoat layer is formed on the barrier pattern and the color filter.

Here, the electrodeposition of the color filter includes immersing the substrate on which the barrier pattern is formed and the metal plate connected to the pixel electrode in the electrodeposition liquid, forming an electric field by applying a voltage to the pixel electrode and the metal plate, and coloring the color filter on the pixel electrode. It comprises the step of.

In addition, the electric field forming step may include applying a voltage to the gate wiring and applying a voltage to the data wiring electrically connected to the pixel electrode.

As described above, in the present invention, the color filter is formed on the lower array substrate to prevent defects of the liquid crystal display and to improve the aperture ratio, and the color filter is formed by electrodeposition to simplify the process and reduce the consumption of materials. Therefore, manufacturing cost can be reduced.

Recently, a method of forming a color filter on an array substrate to prevent misalignment of an LCD and to improve an aperture ratio has been proposed. In this case, the color filter may be formed above the thin film transistor, or may be formed below the thin film transistor. The former is called a color filter on thin film transistor (COT) structure, and the latter is called a thin film transistor on color filter (TOC) structure.

In the COT structure, since the color filter is positioned above the pixel electrode, the color filter may be formed on the pixel electrode using the electrodeposition method. Electrodeposition method is a method of forming a color filter film on the electrode by using an electrochemical reaction, it can make a large area, low material consumption, and does not require a separate exposure and development process has the advantage of a simple process.

Hereinafter, a liquid crystal display of a color filter on thin film transistor structure according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a plan view of an array substrate for a color filter on thin film transistor structure liquid crystal display device, and FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2.

2 and 3, the gate wiring 221 in the horizontal direction made of a conductive material such as a metal on the transparent substrate 210, the gate electrode 222 extending from the gate wiring 221, and the gate wiring ( A gate pad 223 positioned at one end of the 221 is formed.

A gate insulating film 230 made of a silicon nitride film or a silicon oxide film is formed thereon to cover the gate wiring 221, the gate electrode 222, and the gate pad 223.

An active layer 241 made of amorphous silicon is formed on the gate insulating layer 230 on the gate electrode 222, and ohmic contact layers 251 and 252 made of amorphous silicon doped with impurities are formed thereon.

On the ohmic contact layers 251 and 252, a data line 261 made of a conductive material such as a metal and defining a pixel area orthogonal to the gate line, a source electrode 262 extending from the data line 261, and a gate A drain electrode 263 facing the source electrode 262 and a data pad 264 positioned at one end of the data line 261 are formed around the electrode 222. The source and drain electrodes 262 and 263 are formed. ) Forms the thin film transistor T together with the gate electrode 222.

Next, a protective layer 270 made of a silicon nitride film, a silicon oxide film, or an organic insulating film is formed on the data line 261, the source and drain electrodes 262 and 263, and the data pad 264, and the protective layer 270. The first and third contact holes 271, 272, and 273 exposing the drain electrode 263, the gate pad 223, and the data pad 264, respectively.

Next, a pixel electrode 281 made of a transparent conductive material, an auxiliary gate pad 282, and an auxiliary data pad 283 are formed on the passivation layer 270. The pixel electrode 281 is connected to the drain electrode 263 through the first contact hole 271, and partially overlaps the gate line 221 to form a storage capacitor. The auxiliary gate pad 282 and the auxiliary data pad 283 are connected to the gate pad 223 and the data pad 264 through the second and third contact holes 272 and 273, respectively.

A barrier pattern 291 made of an organic resin is formed in an area other than the pixel electrode 281, that is, the gate wiring 221, the data wiring 261, and the thin film transistor T, and the pixel electrode A color filter 292 is formed on the 281. Here, the barrier pattern 291 prevents defects when the color filter 292 is formed, and serves to distinguish colors of the color filter 292, and the color filter 292 sequentially forms red, green, and blue colors. And one color corresponds to one pixel electrode 281.

An overcoat layer 300 is formed on the barrier pattern 291 and the color filter 292 to protect them, and the overcoat layer 300 is made of a transparent resin.

4 illustrates a liquid crystal display using an array substrate having a COT structure according to the present invention.

As shown in FIG. 4, the thin film transistor T and the pixel electrode 281 connected to the thin film transistor T are formed on the lower substrate 210, and the barrier pattern 291 is formed on the thin film transistor T. Although not shown, the barrier pattern 291 is formed on a portion other than the pixel electrode 281 and has an opening that exposes the pixel electrode 281. Red, green, and blue color filters 292 are formed on the pixel electrode 281, and one color corresponds to one pixel electrode 281. An overcoat layer 300 is formed on the barrier pattern 291 and the color filter 292 to protect them.

The upper substrate 410 is formed on the lower substrate 210 by being spaced apart from the lower substrate 210 by a predetermined distance. On the inner surface of the upper substrate 410, the black matrix 420 is positioned at a position corresponding to the thin film transistor T. ), And a common electrode 430 made of a transparent conductive material is formed over the entire surface of the substrate 410.

The liquid crystal layer 500 is injected between the upper substrate 410 and the lower substrate 310.

Although not shown, an alignment layer is formed on the overcoat layer 300 and the common electrode 430, respectively, and the alignment layers are arranged in a predetermined direction to determine initial alignment of the liquid crystal molecules of the liquid crystal layer 500.

As described above, since the color filter is formed on the lower substrate, misalignment of the color filter and the pixel electrode does not occur when the upper substrate and the lower substrate are bonded together. Therefore, the adhesion margin of the black matrix of the upper substrate may be reduced, and when the barrier pattern is formed of a black matrix material that prevents light transmission, the black matrix of the upper substrate may be omitted, thereby improving the aperture ratio of the liquid crystal display device. You can.

Hereinafter, the manufacturing method of the array substrate for liquid crystal display devices of such a COT structure is demonstrated in detail with reference to drawings.

5A to 5F illustrate a manufacturing process of an array substrate according to an exemplary embodiment of the present invention, which corresponds to a cross section taken along line III-III of FIG. 2.

As shown in FIG. 5A, a conductive material such as a metal is deposited and patterned on the substrate 210 to form a gate wiring 221 extending in the horizontal direction, a gate electrode 222 extending from the gate wiring 221, and a gate wiring. A gate pad 223 positioned at one end of the 221 is formed. Next, the gate insulating layer 230, the amorphous silicon layer, and the amorphous silicon layer doped with impurities are sequentially deposited and then patterned to form the impurity semiconductor layer 253 and the active layer 241.

Subsequently, as illustrated in FIG. 5B, a material such as a metal is deposited and patterned by a sputtering method to intersect with the gate wiring 221 to define the pixel region, and thus, the data wiring 261 and the source electrode connected to the data wiring 261. 262, a drain electrode 263 spaced apart from the source electrode 262 and positioned opposite the source electrode 262 with respect to the gate electrode 222, and a data pad positioned at one end of the data wire 261. After forming 264, the impurity semiconductor layer 253 exposed between the source electrode 262 and the drain electrode 263 is etched to complete the ohmic contact layers 251 and 252.

Next, as shown in FIG. 5C, an inorganic insulating film or an organic insulating film is formed and patterned together with the gate insulating film 230 to expose the drain electrode 263, the gate pad 223, and the data pad 264, respectively. Three contact holes 271, 272, and 273 are formed. Subsequently, the transparent conductive material is deposited and patterned to form the pixel electrode 281, the auxiliary gate pad 282, and the auxiliary data pad 283. The pixel electrode 281 is formed in the pixel area and contacts the drain electrode 263 through the first contact hole 271, and partially overlaps the gate wiring 221 to form a storage capacitor. The auxiliary gate pad 282 and the auxiliary data pad 283 are connected to the gate pad 223 and the data pad 264 through the second and third contact holes 272 and 273, respectively.

Next, as shown in FIG. 5D, a barrier pattern 291 having an opening that exposes the pixel electrode 281 is formed by applying and patterning an organic material. The barrier pattern 291 is positioned on the gate wiring 221, the data wiring 261, and the thin film transistor T. Since the pixel electrode 281 partially overlaps the gate wiring 221, the barrier pattern 291 is also gated. A portion of the wiring 221 overlaps with the wiring 221. Here, the barrier pattern 291 is formed to have a width wider than that of the data line 261 and to have an opening substantially the same as that of the pixel electrode 281. However, the barrier pattern 291 has the same width as that of the data line 261. May have The barrier pattern 291 may be formed using an organic material such as benzocyclobutene (BCB) or an organic material used as a black matrix. The barrier pattern 291 is for preventing defects in forming the color filter. When the voltage is applied to the pixel electrode when forming the color filter using the electrodeposition method, an electric field is generated and electrodeposition is performed by the generated electric field. The color filter may be electrodeposited to the neighboring pixel electrode or the portion other than the pixel electrode, which is spread around and can be prevented by forming the barrier pattern 291.

Next, as illustrated in FIG. 5E, the color filter 292 is electrodeposited on the pixel electrode 281 exposed by the barrier pattern 291.

In this case, a metal plate (not shown) connected to the pixel electrode 281 and the pixel electrode 281 is placed in the substrate 210 having the barrier pattern 291 formed in a solution in which an anionic polymer such as a polyester resin is mixed with a colorant. When a voltage is applied to the colorant, the colorant moves to the pixel electrode 281 together with the polymer to be electrodeposited to form the color filter 292.

In the present invention, voltage is applied to the pixel electrode 281 using the gate wiring 221 and the data wiring 261. That is, the thin film transistor T is operated by applying a voltage to the gate wiring 221, and the applied voltage is transferred to the pixel electrode 281 through the thin film transistor T by applying a voltage to the data wiring 261. do. Then, an electric field is formed between the pixel electrode 281 and the metal plate, and the colorant moves to the pixel electrode 281 together with the ionic polymer to be electrodeposited on the pixel electrode 281 to form the color filter 292.

Therefore, it is not necessary to separately form a metal layer for applying a voltage to the pixel electrode 281.

By selectively applying a voltage to the data line 261 in this manner, the red, green, and blue color filters 292 can be formed at desired positions, respectively.

Next, as shown in FIG. 5F, an overcoat layer 300 made of a transparent resin is formed to protect the color filter 292. Subsequently, the barrier layer 291 and the overcoat layer 300 on the auxiliary gate pad 282 and the auxiliary data pad 283 are patterned to expose the auxiliary gate pad 282 and the auxiliary data pad 283, respectively.

In the present invention, the overcoat layer 300 and the barrier layer 291 on the auxiliary gate pad 282 and the auxiliary data pad 283 are partially removed from the pad portion, but the overcoat layer 300 and the barrier layer 291 of the pad portion are removed. In some embodiments, the overcoat layer 300 and the barrier layer 291 may be disposed on the auxiliary pads 282 and 283 to expose the auxiliary gate pad 282 and the auxiliary data pad 283.

As described above, since the red, green, and blue color filters are colored using an electric field, the exposure and development processes are not required, so the process is reduced, and the color filter can be formed only at a desired position, thereby reducing the consumption of materials. Therefore, manufacturing cost can be reduced.

The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit of the present invention.

In the array substrate for a liquid crystal display device and the method of manufacturing the same according to the present invention, by forming a color filter on the array substrate, it is possible to reduce defects and improve the aperture ratio when bonding the upper and lower substrates of the liquid crystal display device, and the part other than the pixel electrode. After the barrier pattern is formed on the electrode, the color filter is electrodeposited to prevent defects, and the color filter is formed using the electrodeposition method, thereby reducing the manufacturing process and reducing the consumption of materials.

Claims (6)

Board; Gate and data lines formed on the substrate and perpendicular to each other; A thin film transistor electrically connected to the gate line and the data line; A passivation layer covering the gate line, the data line and the thin film transistor; A pixel electrode formed on the passivation layer and connected to the thin film transistor; A barrier pattern formed on the pixel electrode and having an opening corresponding to the pixel electrode and formed of an organic insulating film; A color filter electrodeposited on the pixel electrode corresponding to the opening and formed of red, green, and blue; An overcoat layer disposed on the barrier pattern and the color filter; Array substrate for a liquid crystal display device comprising a. delete In claim 1, The barrier pattern is an array substrate for a liquid crystal display device made of any one of benzocyclobutin (BCB) or black resin. Providing a substrate; Forming a thin film transistor connected to the gate wire and the data wire, and the gate wire and the data wire orthogonal to each other on the substrate; Forming a passivation layer on the gate line, the data line, and the thin film transistor; Forming a pixel electrode on the passivation layer and connected to the thin film transistor; Forming a barrier pattern on the pixel electrode having an opening corresponding to the pixel electrode with an organic insulating layer; Electrodepositing a color filter on the pixel electrode corresponding to the opening; Forming an overcoat layer on the barrier pattern and the color filter; Method of manufacturing an array substrate for a liquid crystal display device comprising a. In claim 4, The electrodeposition of the color filter may include immersing a metal plate connected to the substrate on which the barrier pattern is formed and the pixel electrode in an electrodeposition liquid; Forming an electric field by applying a voltage to the pixel electrode and the metal plate; Coloring the color filter on the pixel electrode; Method of manufacturing an array substrate for a liquid crystal display device comprising a. In claim 5, The forming of the electric field may include applying a voltage to the gate wiring; And applying a voltage to the data line electrically connected to the pixel electrode.

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