KR20070119239A - Liquid crystal display apparatus and method of fabricating the same - Google Patents

Abstract

An LCD(Liquid Crystal Display) and a manufacturing method thereof are provided to set a correct joining position of an array substrate and a color filter substrate by enabling an alignment device to recognize exactly first and second align keys, thereby improving production yield by preventing join failure between the array substrate and the color filter substrate. An LCD(700) includes an array substrate(100), an opposite substrate(200), and a liquid crystal layer. The array substrate includes a first base substrate(110), a pixel unit, at least one align key(AK1~AK4), and a first protective pad. The first base substrate is divided into a display area(DA) and a surrounding area surrounding the display area. The pixel unit is formed in the display area to display an image. The align key is formed in the surrounding area. The first protective pad covers the upper side of the first align key and the circumference of the first align key. The opposite substrate includes a second base substrate, a common electrode, and at least one second align key. The liquid crystal layer is interposed between the array substrate and the opposite substrate to control the transmission rate of light.

Description

Liquid crystal display and manufacturing method {LIQUID CRYSTAL DISPLAY APPARATUS AND METHOD OF FABRICATING THE SAME}

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

FIG. 2 is a cross-sectional view taken along the line II ′ of FIG. 1.

3 is an enlarged plan view illustrating a portion 'A' of FIG. 1.

4 is a cross-sectional view taken along the line II-II ′ of FIG. 3.

5A through 5C are process diagrams illustrating a process of forming the array substrate illustrated in FIG. 1.

6A through 6C are process diagrams illustrating a process of forming the color filter substrate illustrated in FIG. 1.

* Description of the symbols for the main parts of the drawings *

100-array substrate 180: first alignment key

190-first protective pad 200: facing substrate

260-Second alignment key 270: Second protective pad

The present invention relates to a liquid crystal display device and a manufacturing method thereof, and more particularly, to a liquid crystal display device and a manufacturing method thereof that can improve the yield of the product by minimizing the coupling error of the substrates.

The liquid crystal display includes an array substrate in which a plurality of pixels are formed in an array form, a color filter substrate and a liquid crystal layer coupled to face the array substrate. The color filter substrate includes a plurality of color pixels expressing a predetermined color and a black matrix surrounding each color pixel.

Here, the plurality of pixels and the plurality of color pixels have an organic relationship with each other. That is, the plurality of pixels adjust the transmittance of light provided to the plurality of color pixels by applying a pixel voltage to the liquid crystal, and the plurality of color pixels receive the adjusted light to express a predetermined color. As described above, the plurality of color pixels differ in the amount of incident light corresponding to the pixel voltages output from the plurality of pixels. Therefore, if the positions of the plurality of pixels and the plurality of color pixels do not exactly match, the image cannot be displayed normally.

To prevent this, the array substrate has a first alignment key, and the color filter substrate has a second alignment key corresponding to the first alignment key. That is, the position of the alignment between the array substrate and the color filter substrate is set by adjusting the position between the first alignment key and the second alignment key.

In general, the array substrate and the color filter substrate align the liquid crystal using a rubbing device in which a rubbing cloth is wound. The first and second alignment keys may be modified in shape by the pressure that the rubbing device presses. In addition, the thin film forming the array substrate and the color filter substrate are not provided on the upper surface of each alignment key, and a step is generated between each alignment key and the periphery of the alignment key. For this reason, the foreign material which adhered to the rubbing cloth may remain in the periphery of each alignment key.

As such, when the shape of the first and second alignment keys is deformed or foreign matter remains on the periphery of the first and second alignment keys, the shapes of the first and second alignment keys may not be correctly recognized. As a result, since the alignment between the array substrate and the color filter substrate cannot be accurately performed, the coupling failure of the liquid crystal display panel occurs, and the yield of the product is reduced.

An object of the present invention is to provide a liquid crystal display device which can improve the yield of the product by accurately setting the bonding position of the array substrate and the opposing substrate.

It is also an object of the present invention to provide a method of manufacturing the above liquid crystal display device.

A liquid crystal display device according to one feature for realizing the above object of the present invention comprises an array substrate, a color filter substrate, and a liquid crystal layer.

The array substrate includes a first base substrate, a pixel portion, at least one first alignment key, and a first protection pad. The first base substrate is partitioned into a display area in which an image is displayed and a peripheral area surrounding the display area. A pixel portion is formed in the display area to display the image. A first alignment key is formed in the peripheral area. The first protective pad covers an upper surface of the first alignment key and a periphery of the first alignment key.

On the other hand, the opposing substrate includes a second base substrate, a common electrode and at least one second alignment key. The second base substrate is coupled to face the first base substrate. The common electrode is formed on the second base substrate. The second alignment key is formed on the second base substrate in correspondence with the first alignment key, and is aligned with the first alignment key when the first base substrate and the second base substrate are coupled to each other.

The liquid crystal layer is interposed between the array substrate and the counter substrate to adjust the light transmittance.

Advantageously, said opposing substrate further comprises a second protective pad covering an upper surface of said second alignment key and a periphery of said second alignment key.

The array substrate may further include a first alignment layer formed on the first base substrate on which the pixel portion, the first alignment, and the first protection pad are formed, and the opposing substrate further includes a second alignment layer formed on the common electrode. . First and second rubbing patterns for aligning liquid crystal molecules are formed on upper surfaces of the first and second alignment layers, respectively.

In addition, the liquid crystal display device manufacturing method according to one feature for realizing the above object of the present invention is as follows.

First, an array substrate is manufactured, and an opposing substrate that displays an image by combining with the array substrate is manufactured.

Here, the array substrate is manufactured through the following process. First, at least one switching element and at least one first alignment key are formed on the first base substrate. A first transparent conductive layer is formed on the first base substrate on which the switching element and the first alignment key are formed. The first transparent conductive layer is patterned to form a first protection pad on an upper surface of the first alignment key and around the first alignment key, and to form a pixel electrode electrically connected to the switching element. A first alignment layer is formed on the first base substrate on which the first protective pad and the switching element are formed. The first alignment layer is rubbed to form a first rubbing pattern on an upper surface of the first alignment layer.

According to such a liquid crystal display and a method of manufacturing the same, the first and second protective pads respectively covering the first and second alignment keys are provided, so that foreign matter is formed on the periphery of the first and second alignment keys during the rubbing process. To prevent it from remaining. As a result, since the first and second alignment keys can be accurately recognized from the outside, the coupling failure between the array substrate and the counter substrate can be prevented.

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

1 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II ′ of FIG. 1.

1 and 2, the liquid crystal display 700 may include an array substrate 100, a color filter substrate 200, a liquid crystal layer 300, first and second drivers 400 and 500, and a flexible circuit unit. And 600.

The array substrate 100 may include a first base substrate 110, a plurality of data lines DL1, DLm, a plurality of gate lines GL1, GLn, a plurality of pixel units, and a gate insulating layer. 140, a passivation layer 150, an organic insulating layer 160, and a first alignment layer 170.

The first base substrate 110 is made of a material capable of transmitting light, such as glass, quartz, sapphire or silicon. The first base substrate 110 is divided into a display area DA in which an image is displayed and a peripheral area PA surrounding the display area PA. The image is not displayed in the peripheral area PA.

The plurality of data lines DL1,..., DLm and the plurality of gate lines GL1,..., GLn are formed on the first base substrate 110. The plurality of data lines DL1,..., DLm are electrically connected to the first driver 400, and provide a data signal corresponding to the image to each pixel unit. The plurality of gate lines GL1 to GLn are insulated from and cross the plurality of data lines DL1 to DLm. The plurality of gate lines GL1,..., GLm are electrically connected to the second driver 500 to provide a gate signal to each pixel unit.

The plurality of pixel units are formed on the first base substrate 110 and are arranged in an array shape. Each pixel portion is defined by the plurality of data lines DL1, ..., DLm and the plurality of gate lines GL1, ..., GLn.

The pixel portion Px includes a thin film transistor (TFT) 120 and a pixel electrode 130 that apply and block a pixel voltage to the liquid crystal layer 300.

The TFT 120 may include a gate electrode 121 formed on the first base substrate 110, an active layer 122 formed on the gate electrode 121, and an ohmic contact formed on the active layer 122. The layer 123 includes source and drain electrodes 124 and 125 provided on the ohmic contact layer 123.

In detail, the gate electrode 121 is formed by branching from a gate line defining the pixel portion Px, and receives the gate signal from the gate line.

The gate insulating layer 140 is formed on an upper surface of the first base substrate 110 on which the gate electrode 121 is formed.

The active layer 122 is formed on an upper surface of the gate insulating layer 140. The active layer 122 is positioned to correspond to the gate electrode 121 and is made of amorphous silicon. The ohmic contact layer 123 made of n + amorphous silicon is formed on an upper surface of the active layer 122. The active layer 122 is exposed through the channel region CA formed by partially removing the ohmic contact layer 123.

The source electrode 124 and the drain electrode 125 are formed on an upper surface of the ohmic contact layer 123. The source electrode 124 is branched from a data line defining the pixel portion Px. The drain electrode 125 faces the source electrode 124 with the channel region CA therebetween.

The passivation layer 150 and the organic insulating layer 160 are sequentially formed on the first base substrate 110 on which the TFT 120 is formed. The drain electrode 125 is exposed through the contact hole CH formed by partially removing the passivation layer 150 and the organic insulating layer 160.

The pixel electrode 130 is formed on the top surface of the organic insulating layer 160. The pixel electrode 130 is electrically connected to the drain electrode 125 through the contact hole CH. The pixel electrode 130 is made of a transparent conductive material, for example, indium tin oxide (ITO) or indium zinc oxide (IZO).

The first alignment layer 170 is formed on the glass insulating layer 160 on which the pixel electrode 130 is formed. A first rubbing pattern is formed on an upper surface of the first alignment layer 170 to orient the liquid crystal molecules of the liquid crystal layer 300 in a specific direction.

The color filter substrate 200 is coupled to face the array substrate 100. The color filter substrate 200 includes a second base substrate 210, a color filter layer 220, an overcoat layer 230, a common electrode 240, and a second alignment layer 250.

The second base substrate 210 may be formed of a transparent material, for example, glass or quartz, which faces the first base substrate 110 and may transmit light.

The color filter layer 220 is formed on an upper surface of the second base substrate 210. The color filter layer 220 includes color pixels 221 expressing a predetermined color by using light and a black matrix 222 surrounding each color pixel. The black matrix 222 blocks light leaking from each color pixel to improve color contrast ratio.

The overcoat layer 230 may be formed on the upper surface of the color filter layer 220 to planarize the color filter substrate 200, and thus the liquid crystal display 700 may maintain a uniform cell gap.

The common electrode 240 is formed on an upper surface of the overcoat layer 230 to provide a common voltage to the liquid crystal layer 300. The common electrode 240 is made of a transparent conductive material such as ITO and IZO.

The second alignment layer 250 is formed on an upper surface of the common electrode 240. A second rubbing pattern is formed on the top surface of the second alignment layer 250 to align the liquid crystal molecules in a specific direction. Here, the second rubbing pattern is formed in a direction perpendicular to the first rubbing pattern.

The array substrate 100 and the color filter substrate 200 include first to fourth alignment units AK1, AK2, AK3, and AK4 for adjusting a coupling position between the two substrates 100 and 200.

In this embodiment, the liquid crystal display 700 includes four alignment parts AK1, AK2, AK3, and AK4, but the number of the alignment parts increases according to the size and structure of the liquid crystal display device 700. Can be reduced.

The first to fourth alignment parts AK1, AK2, AK3, and AK4 are positioned in the peripheral area PA. Preferably, the first to fourth alignment units AK1, AK2, AK3, and AK4 are positioned adjacent to each corner of the color filter substrate 200, respectively.

In this embodiment, the first to fourth alignment portions AK1, AK2, AK3, and AK4 have the same structure. Therefore, hereinafter, in the detailed description of the structures of the first to fourth alignment units AK1, AK2, AK3, and AK4, the first alignment unit AK1 will be described as an example.

3 is an enlarged plan view of portion 'A' of FIG. 1, and FIG. 4 is a cross-sectional view taken along the line II-II 'of FIG. 3.

3 and 4, the first alignment unit AK1 may include a first alignment key 180 formed on the array substrate 100 and a second alignment key formed on the color filter substrate 200. 260.

In detail, the first alignment key 180 is formed on an upper surface of the first base substrate 110 and is made of a metal material that reflects light. The first alignment key 180 has a quadrangular shape, and a central portion thereof is removed to form an opening.

A first protective pad 190 is formed on the top surface of the first alignment key 180. The first protection pad 190 is made of a transparent conductive material such as ITO or IZO to recognize the first alignment key 180 from the outside.

The first protection pad 190 prevents foreign matter from remaining on the periphery of the first alignment key 180 in the process of forming the first rubbing pattern on the first alignment layer 170 (see FIG. 2). do.

That is, the foreign matter may remain in the periphery of the first alignment key 180 due to the step between the first alignment key 180 and the peripheral portion of the first alignment key 180. The first protection pad 190 covers the upper surface of the first alignment key 180 and the periphery of the first alignment key 180 so that the foreign material is disposed on the periphery of the first alignment key 180. To prevent it from remaining. Accordingly, an alignment device (not shown) for adjusting the coupling position of the array substrate 100 and the color filter substrate 200 may accurately recognize the shape of the first alignment key 180. A poor coupling of the array substrate 100 and the color filter substrate 200 may be prevented.

In this case, an insulating layer, for example, the passivation layer 150 or the organic insulating layer 160, is not formed on the first alignment key 180. Since the insulating film is softer than a conductive transparent electrode such as the ITO or the IZO, more foreign matter may remain in the periphery of the first alignment key 180.

In addition, the first protective pad 190 prevents the shape of the first alignment key 180 from being deformed in the process of forming the first rubbing pattern. That is, the shape of the first alignment key 180 may be deformed due to the pressure pressed by the rubbing device (not shown) for forming the first rubbing pattern. The first protective pad 190 absorbs the pressure applied by the rubbing device to prevent deformation of the first alignment key 180.

The second alignment key 260 is formed on the upper surface of the second base substrate 210 and is made of the same material as the black matrix 222 (see FIG. 2). The second alignment key 260 includes a main key 261 and a plurality of sub keys 262a, 262b, 262c, and 262d.

The main key 261 has a rectangular shape and is positioned in an area corresponding to the opening of the first alignment key 180. Therefore, the first alignment key 180 is located in an area corresponding to the periphery of the main key 261. The size of the main key 261 is smaller than the opening of the first alignment key 180.

The plurality of sub keys 262a, 262b, 262c, and 262d are located in an area corresponding to the periphery of the first align key 180, and each of the sub keys 262a, 262b, 262c, and 262d is the first key. In correspondence with each corner of the in key 180.

When the array substrate 100 is coupled to the color filter substrate 200, a positional relationship between the first alignment key 180 and the second alignment key 260, for example, the color filter substrate 200 When the liquid crystal display 700 is viewed from above, the distance between the first align key 180 and the main key 261 is adjusted and combined.

A second protective pad 270 is formed on an upper surface of the second base substrate 210 on which the second alignment key 260 is formed. The second protective pad 270 is made of a transparent conductive material such as ITO or IZO to externally recognize the second alignment key 260.

The second protective pad 270 prevents foreign matter from remaining in the periphery of the second alignment key 260 in the process of forming the second rubbing pattern on the second alignment layer 250 (see FIG. 2). do.

That is, the foreign matter may remain in the periphery of the second alignment key 260 due to the step between the second alignment key 260 and the peripheral portion of the second alignment key 260. The second protection pad 270 covers the upper surface of the second alignment key 260 and the periphery of the second alignment key 260 so that the foreign material is surrounded by the periphery of the second alignment key 260. To prevent it from remaining. Accordingly, since the alignment device can accurately recognize the shape of the second alignment key 260, the coupling failure of the array substrate 100 and the color filter substrate 200 can be prevented.

In addition, the second protective pad 270 prevents the shape of the second alignment key 260 from being deformed in the process of forming the second rubbing pattern. That is, the shape of the second alignment key 260 may be deformed due to the pressure pressed by the rubbing device in the process of forming the second rubbing pattern. The second protective pad 270 absorbs the pressure applied by the rubbing device to prevent deformation of the second alignment key 260.

1 and 2, the liquid crystal layer 300 is interposed between the array substrate 100 and the color filter substrate 200. The liquid crystal layer 300 is positioned in the display area DA and adjusts light transmittance according to an electric field formed between the pixel electrode 130 and the common electrode 240. The liquid crystal molecules are aligned in a specific direction according to the first and second rubbing patterns formed on the first and second alignment layers 170 and 250, respectively.

The first and second drivers 400 and 500 are mounted on the peripheral area PA of the array substrate 100.

The first driver 400 may include the flexible circuit unit 600 and the plurality of data lines DL1,... Between the flexible circuit unit 600 and the plurality of data lines DL1,..., DLm. , DLm) is electrically connected. The first driver 400 receives an image signal corresponding to the image from the flexible circuit unit 600, and outputs the data signal to the plurality of data lines DL1, DLm.

The second driver 500 is electrically connected to the plurality of gate lines GL1,..., GLn to output the gate signals to the plurality of gate lines GL1,..., GLn.

Hereinafter, a method of manufacturing the liquid crystal display device 700 will be described in detail with reference to the accompanying drawings.

5A through 5C are process diagrams illustrating a process of forming the array substrate illustrated in FIG. 1.

Referring to FIG. 5A, a first metal layer (not shown) is deposited on the upper surface of the first base substrate 100. Subsequently, the metal layer is patterned to form the gate electrode 121 in the display area DA, and the first alignment key 180 is formed in the peripheral area PA. Although not shown in FIG. 5A, the plurality of gate lines GL1,..., GLn are also formed in the process of forming the gate electrode 121.

In this embodiment, the first alignment key 180 is formed in the same process as the process of forming the gate electrode 121 and is formed together in the process of forming the gate electrode 121. However, the first alignment key 180 may form the source electrode 124 and the drain electrode 125 through the same process as the process of forming the source electrode 124 and the drain electrode 125. It may be formed together in the process.

2, 5B and 5C, the gate insulating layer 140 and the active layer on the first base substrate 110 on which the gate electrode 121 and the first alignment key 180 are formed. The TFT 120 is completed by forming the ohmic contact layer 123, the source electrode 124, and the drain electrode 125. The passivation layer 150 and the organic insulating layer 160 are sequentially formed on the first base substrate 110 on which the TFT 120 is formed.

The gate insulating layer 140, the passivation layer 150, and the organic insulating layer 160 are removed in a region where the first alignment key 180 is formed.

A first transparent conductive layer EL1 made of a conductive material is deposited on the first base substrate 110 on which the organic insulating layer 160 is formed. The first transparent conductive layer EL1 is formed on the entire area of the first base substrate 110.

As illustrated in FIG. 5C, the first transparent conductive layer EL1 is patterned to form the pixel electrode 130 and the first protective pad 190.

As illustrated in FIG. 2, the first alignment layer 170 is deposited on the first base substrate 110 on which the pixel electrode 130 and the first projection electrode 190 are formed. The first rubbing pattern is formed on the top surface of the alignment layer 170. As a result, the array substrate 100 is completed.

6A through 6C are process diagrams illustrating a process of forming the color filter substrate illustrated in FIG. 1.

Referring to FIG. 6A, a second metal layer (not shown) is deposited on the top surface of the second base substrate 210. The black metal layer 222 and the second alignment key 260 are formed by patterning the second metal layer. In this embodiment, the black matrix 222 and the second alignment key 260 is made of a metal material, but may be made of an organic material.

Referring to FIG. 6B, the color pixels 221 are formed on the second base substrate 210 on which the black matrix 222 and the second alignment key 260 are formed. Subsequently, an overcoat layer 230 is formed on the top surface of the color filter layer 220.

2 and 6C, a second transparent conductive layer is formed on the overcoat layer 230 to form the common electrode 240 and the second protective pad 270.

In this embodiment, the second protection pad 270 is integrally formed with the common electrode 240, but the second protection pad 270 may be formed separately from the common electrode 240.

As illustrated in FIG. 2, the second alignment layer 250 is deposited on the second base substrate 210 on which the common electrode 240 and the second protection pad 270 are formed. The second rubbing pattern is formed on the top surface of the alignment layer 250. Thus, the color filter substrate 200 is completed.

The array substrate 100 formed through the process illustrated in FIGS. 5A to 5C and the color filter substrate 200 formed through the process illustrated in FIGS. 6A to 6C are combined to form the array substrate 100. ) And the color filter substrate 300 are injected between the color filter substrate 200 to complete the liquid crystal display device 700.

According to the present invention described above, the liquid crystal display device includes first and second protective pads respectively covering first and second alignment keys for adjusting the coupling position of the array substrate and the color filter substrate. Accordingly, the liquid crystal display prevents foreign substances generated in the process of forming the rubbing pattern from remaining at the periphery of each alignment key because of the step difference between each alignment key and the peripheral portion of each alignment key. Further, the first and second protective pads can absorb the pressure that the rubbing device presses to prevent the shape of the first and second alignment keys from being deformed by the rubbing device.

Accordingly, since the alignment device can accurately recognize the first and second alignment keys, the alignment position of the array substrate and the color filter substrate can be accurately set. Therefore, the liquid crystal display device can prevent the coupling failure between the array substrate and the color filter substrate, thereby improving the yield of the product.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (9)

A first base substrate partitioned into a display area in which an image is displayed and a peripheral area surrounding the display area, a pixel portion formed in the display area to display the image, at least one first alignment key formed in the peripheral area, And a first protective pad covering an upper surface of the first alignment key and a periphery of the first alignment key. A second base substrate facing the first base substrate and coupled to the first base substrate, a common electrode formed on the second base substrate, and formed on the second base substrate so as to correspond to the first alignment key; An opposing substrate having at least one second alignment key aligned with the first alignment key upon joining of the substrate and the second base substrate; And And a liquid crystal layer interposed between the array substrate and the opposing substrate to control light transmittance. The method of claim 1, wherein the pixel unit, A switching element configured to output a pixel voltage corresponding to the image; And And a pixel electrode electrically connected to the switching element and providing the pixel voltage to the liquid crystal layer. The liquid crystal display of claim 2, wherein the first protective pad is made of the same material as the pixel electrode. The method of claim 1, The array substrate may be formed on the first base substrate on which the pixel portion, the first alignment key, and the first protective pad are formed, and a first rubbing pattern may be formed on the upper surface thereof to orient the liquid crystal molecules of the liquid crystal layer. Further comprising a first alignment layer, The counter substrate further includes a second alignment layer formed on the common electrode and having a second rubbing pattern formed on the upper surface thereof to orient the liquid crystal molecules of the liquid crystal layer. The method of claim 4, wherein the opposing substrate, And a second protection pad covering an upper surface of the second alignment key and a periphery of the second alignment key. The liquid crystal display of claim 5, wherein the second protection pad is made of the same material as the common electrode. The liquid crystal display of claim 6, wherein the second protective pad is formed integrally with the common electrode. Manufacturing an array substrate; And Manufacturing an opposing substrate in combination with the array substrate to display an image; Manufacturing the array substrate, Forming at least one switching element and at least one first alignment key on the first base substrate; Forming a first transparent conductive layer on the first base substrate on which the switching element and the first alignment key are formed; Patterning the first transparent conductive layer to form a first protection pad on an upper surface of the first alignment key and around the first alignment key, and forming a pixel electrode electrically connected to the switching element; Forming a first alignment layer on the first base substrate on which the first protection pad and the switching element are formed; And And rubbing the first alignment layer to form a first rubbing pattern on an upper surface of the first alignment layer. The method of claim 8, wherein the manufacturing of the opposing substrate comprises: Forming at least one second alignment key corresponding to the first alignment key on a second base substrate; A second protective pad covering the upper surface of the second alignment key and a periphery of the second alignment key by forming a second transparent conductive layer on the second base substrate on which the second alignment key is formed; Forming an electrode; Forming a second alignment layer on the second base substrate on which the second protection pad and the common electrode are formed; Rubbing the second alignment layer to form a second rubbing pattern on an upper surface of the second alignment layer; Coupling the first base substrate and the second base substrate by aligning the first alignment key and the second alignment key; And And forming a liquid crystal layer between the first base substrate and the second base substrate.

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