KR20080029397A - Color filter substrate and fabrication method thereof, liquid crystal display having this - Google Patents

Abstract

A color filter substrate, a method for manufacturing the same, and an LCD(Liquid Crystal Display) having the same are provided to maintain a uniform cell gap throughout the entire area by dividing an effective region into a central region and an outer region, forming the first column spacers and the second column spacers at the central region and an outer region respectively, and forming the second column spacers more highly than the first column spacers. A color filter substrate(200) having an effective region which is divided into a central region(A) and an outer region(B) comprises the first column spacers(242a) and the second column spacers(242b). The first column spacers are formed at the central region. The second column spacers are formed at the outer region. The second column spacers, arranged on a lower structure formed of at least either a black matrix(212) or color filters(222a-222d), are higher than the first column spacers.

Description

COLOR FILTER SUBSTRATE AND FABRICATION METHOD THEREOF, LIQUID CRYSTAL DISPLAY HAVING THIS

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

2 is a cross-sectional view illustrating a liquid crystal display device according to a first embodiment of the present invention.

3 is a cross-sectional view illustrating a process of manufacturing a thin film transistor substrate according to the first embodiment of the present invention.

4 is a cross-sectional view showing a manufacturing process of a color filter substrate according to a first embodiment of the present invention.

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

6 is a cross-sectional view showing a manufacturing process of a color filter substrate according to a second embodiment of the present invention.

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

100: thin film transistor substrate 113: gate electrode

114: sustain electrode 153: source electrode

154: drain electrode 182: pixel electrode

200: color filter substrate 212: black matrix

222: color filter 232: overcoat film

242: column spacer 252: common electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a color filter substrate in which a column spacer for maintaining a cell gap is higher at an outer portion than a central portion of a substrate, a manufacturing method thereof, and a liquid crystal display having the same.

Liquid crystal display is a display device that realizes an image by controlling the amount of light incident from a light source using the optical anisotropy of liquid crystal molecules and the polarization characteristics of a polarizing plate. In addition, the power consumption is small, the application range is expanding rapidly in recent years.

The liquid crystal display includes a color filter substrate on which a black matrix, a color filter, a common electrode, and the like are formed, a thin film transistor substrate on which a thin film transistor (TFT), a pixel electrode, and the like are formed, and a liquid crystal layer filled between the two substrates. The liquid crystal is driven by an electric field formed between the common electrode and the pixel electrode to control the transmittance of light to display an image.

On the other hand, the color filter substrate and the thin film transistor substrate are formed through a seal line formed around the edge of one substrate while the distance between the two substrates is kept constant by column spacers formed on one substrate. This is combined to form a liquid crystal cell. In this case, the gap of the liquid crystal cell, that is, the cell gap, is a key management element that absolutely affects the image quality, and is preferably maintained uniformly throughout the substrate.

Recently, as the liquid crystal display device is enlarged, the area of the substrate is rapidly increased, and the area of the outer black matrix for preventing light leakage at the edge is rapidly increased. However, as the area of the outer black matrix is gradually enlarged, the distance from the effective area where the image is displayed to the seal line gradually increases, so that the substrate is struck at the outer part of the effective area adjacent to the outer black matrix. Due to the substrate sagging, the cell gap of the center portion and the outer portion of the effective area is formed differently, and particularly, a screen defect such as a stain occurs in the outer portion.

The present invention was derived to solve the above problems, by adjusting the formation height of the column spacer with at least one film of the black matrix and the color filter, thereby forming a larger cell gap than the cell gap of the center of the effective region Another object of the present invention is to provide a color filter substrate capable of compensating for reduction of cell gap caused by sagging of an outer substrate, a method of manufacturing the same, and a liquid crystal display having the same.

According to an aspect of the present invention, there is provided a color filter substrate including: a color filter substrate having an effective area divided into a center area and an outer area, the plurality of first column spacers formed in the center area, and the outer area; And a plurality of second column spacers formed on the second column spacers, wherein the second column spacers are formed on a lower structure formed of at least one of a black matrix and a color filter, and are formed higher than the first column spacers. .

In this case, the first column spacer may be formed on the lower structure in which the black matrix is not formed, and the second column spacer may be formed on the lower structure in which the black matrix is formed.

Alternatively, the first column spacer may be formed on the lower structure in which the color filter is not formed, and the second column spacer may be formed on the lower structure in which the color filter is formed.

Alternatively, the first column spacer may be formed on a lower structure in which the color filter is formed in a single layer, and the second column spacer may be formed on a lower structure in which the color filter is formed in multiple layers.

In the method for manufacturing a color filter substrate according to the present invention for achieving the above object, in the method for producing a color filter substrate in which a black matrix and a color filter are formed on the substrate, a plurality of agents are provided in the central region and the outer region of the substrate. Forming a first column spacer and a plurality of second column spacers, wherein the step of forming the second column spacer on a substructure formed of at least one of the black matrix and the color filter, thereby forming the second column spacer. Is formed higher than the first column spacer.

The liquid crystal display according to the present invention for achieving the above object is a liquid crystal display device in which the effective area is divided into a center region and an outer region, the plurality of first column spacer formed in the center region and the outer region And a plurality of second column spacers formed in the second column spacers, wherein the second column spacers are formed higher than the first column spacers.

In this case, the second column spacer is preferably formed on a lower structure formed of at least one of a black matrix and a color filter.

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

However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art the scope of the invention. It is provided for complete information. Like reference numerals in the drawings refer to like elements.

<First Embodiment>

First, a liquid crystal display according to a first embodiment of the present invention will be described.

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

Referring to FIG. 1, the liquid crystal display includes an effective area 300 in which unit pixels are formed and an invalid area 400 in which unit pixels are not formed. A frame-shaped black matrix 410 is formed in the non-effective area 400 in which the actual image is not displayed, and a frame-shaped seal line is formed around the periphery of the black matrix 410. line 420 is formed. Hereinafter, the frame-shaped black matrix 410 formed in the invalid area 400 is defined as an 'outer black matrix' by being distinguished from the grid-shaped black matrix formed in the effective area 300.

FIG. 2 is a cross-sectional view of a liquid crystal display according to a first exemplary embodiment of the present invention, and illustrates unit pixels formed at points A and B of FIG. 1. Here, area A means a central portion of the effective area, and area B means an outer portion of the effective area.

Referring to FIG. 2, the liquid crystal display includes a thin film transistor substrate 100, a color filter substrate 200, and a liquid crystal layer formed between the two substrates 100 and 200.

The thin film transistor substrate 100 includes a signal line (not shown) extending crosswise to one side and the other side, a unit pixel (not shown) defined by an intersection area of the signal line, and a switching element and a pixel formed in the unit pixel. A translucent insulating substrate including an electrode 182, a sustain electrode 114, and the like.

The switching element is formed of amorphous silicon, polycrystalline silicon, or the like as a channel layer, and is a thin film transistor including a gate electrode 113, a source electrode 153, a drain electrode 154, and the like. It is effective to use Thin Film Transistor (TFT). In this case, the gate electrode 113 is connected to one signal line, that is, the gate line (not shown), the source electrode 153 is connected to the other signal line, that is, the data line (not shown), and the drain electrode 154 is It is connected to the pixel electrode 182.

The pixel electrode 182 is electrically connected to the drain electrode 154 through a contact hole, and forms a liquid crystal capacitor Clc together with the common electrode 252 of the color filter substrate 200.

The storage electrode 114 is formed together in the same step when forming the gate line or the data line, and at least a portion thereof overlaps the pixel electrode 182 in the upper portion to form the storage capacitor Cst. The sustain capacitor Cst maintains an image signal transmitted to a specific pixel for a predetermined frame (usually one frame) to prevent image shaking, which is an auxiliary role of the liquid crystal capacitor Clc. It may be omitted as necessary.

The color filter substrate 200 may include a black matrix 212 that blocks incident light to prevent optical interference between adjacent pixel areas, and a red (R), green (G), A transparent insulating substrate on which a common electrode 252 for forming an electric field in the liquid crystal layer is formed together with the color filters 222a to 222d; 222 of blue (B) and the pixel electrodes 182 facing each other.

An overcoat layer 232 is formed between the color filter 222 and the common electrode 252 to improve adhesion and flatness of an interface, and is formed on a portion of the overcoat layer 232. Column spacers 242a, 242b; 242 having predetermined heights for maintaining cell gaps are formed. Of course, the overcoat layer 232 may be omitted, if necessary, the column spacer 242 of the black matrix 212, the color filter 222, the overcoat layer 232, the common electrode 252. It can be formed on either film.

The two substrates 100 and 200 are joined by a seal line 420 formed on at least one substrate to form a liquid crystal display. Column spacers are disposed around the effective area 300 of the liquid crystal display to maintain a constant cell gap. 242 is formed.

In the liquid crystal display according to the present exemplary embodiment, since the column spacer 242b formed in an area where the substrate is easily struck is formed higher than the column spacer 242a formed in another region, the liquid crystal display device offsets the decrease in cell gap caused by the substrate drop. The cell gap remains constant throughout. In this case, the height of the column spacers 242a and 242b may be adjusted using the black matrix 212 formed at the lower portion thereof.

That is, the column spacer 242a of the central portion 310 is formed on the lower structure where the black matrix is not formed, whereas the column spacer of the outer portion is formed on the lower structure where the black matrix is formed, and thus is higher than the thickness of the black matrix. Is formed. Due to the height difference between the column spacers 242a and 242b, the cell gap h ₂ of the unit pixel formed in the outer portion 320 is larger than the cell gap h ₁ of the unit pixel formed in the center portion 310 of the effective region (h1). <h2) is formed.

The manufacturing process of the liquid crystal display device according to the first embodiment of the present invention having such a configuration will be described below.

3A to 3E are cross-sectional views illustrating a manufacturing process of a thin film transistor substrate according to a first embodiment of the present invention.

First, as shown in FIG. 3A, a first conductive film is formed on a predetermined substrate 100 by CVD, PVD, sputtering, or the like, and then a patterning process using a first mask is performed to form a gate electrode 113. ), A gate line including a gate line (not shown), and the like, and a sustain electrode 114 and a sustain line (not shown) are formed at the same time. In this case, it is preferable to use a single layer or multiple layers formed of at least one material selected from Mo, Al, Cr, and Ti as the first conductive film.

Subsequently, as shown in FIG. 3B, the first insulating layer 122, the active layer 132, and the ohmic contact layer 142 are sequentially formed on the entire structure including the gate wiring by using a Plasma Enhanced Chemical Vapor Deposition (PECVD) method. The semiconductor layer is stacked to form a semiconductor layer, and then a patterning process using a second mask is performed to form an island-like semiconductor layer on the gate electrode 113. In this case, the first insulating layer 122 uses one or more insulating materials selected from inorganic insulating materials including silicon nitride (SiN _x ) or silicon oxide (SiO ₂ ) having excellent adhesion and insulation properties. An amorphous silicon layer (a-Si) is used as the reference numeral 132, and an amorphous silicon layer (n + a-Si) doped with n-type impurities is preferably used as the ohmic contact layer 142. .

Subsequently, as shown in FIG. 3C, a second conductive layer is formed on the entire structure including the semiconductor layer by CVD, PVD, and sputtering, and then a patterning process using a third mask is performed. 153, a drain electrode 154, a data line including a data line (not shown) and the like are formed. In addition, when the ohmic contact layer 142 is separated between the source electrode 153 and the drain electrode 154 as a barrier, the substrate 100 is arranged in a lattice form corresponding to each unit pixel. A thin film transistor is formed. In this case, it is preferable to use a single layer or multiple layers formed of at least one material selected from Mo, Al, Cr, and Ti as the second conductive film.

Subsequently, as shown in FIG. 3D, the second insulating layer 162 is formed on the entire structure including the data line, and then a patterning process using a fourth mask is performed to expose a portion of the lower line. ). As the second insulating film 162, any one selected from the same inorganic insulating film, organic film, and double layers of the inorganic insulating film and the organic film as the first insulating film 122 may be used.

Subsequently, as shown in FIG. 3E, a transmissive conductive film is formed on the entire structure including the second insulating film, and then a patterning process using a fifth mask is performed to expose the drain electrode 154 through the contact hole 163. A pixel electrode 182 connected to the pixel is formed. In this case, indium tin oxide (ITO) or indium zinc oxide (IZO) may be used as the light transmissive conductive film.

As described above, the thin film transistor substrate 100 is formed by performing a five-step mask process. However, the thin film transistor substrate 100 may be formed by performing a five-step mask process or a five-step mask process.

4A to 4D are cross-sectional views illustrating a manufacturing process of a color filter substrate according to a first embodiment of the present invention.

First, as shown in FIG. 4A, a black matrix light blocking film is coated on a predetermined substrate 200 and then patterned to form a black matrix 212 arranged in a lattice form. In this case, the column spacer 242a of the central portion 310 is formed on the lower structure where the black matrix 212 is not formed, but the column spacer 242b of the outer portion 320 has the lower structure where the black matrix 212 is formed. As it is formed on, it is formed higher by the thickness of the black matrix 212.

Subsequently, as shown in FIG. 4B, an organic film for a color filter is coated on the entire structure including the black matrix 212 and then patterned to form R, G, and B color filters in which the black matrix 212 and a portion thereof overlap. 222 is formed.

Subsequently, as shown in FIG. 4C, the overcoat layer 232 is formed on the entire structure including the color filter 222, the light-transmitting organic layer is coated thereon, and then patterned to form the column spacer 242a for maintaining the cell gap. 242b). In this case, the column spacer 242a of the central portion 310 is formed on the lower structure in which the black matrix 212 is not formed, but the column spacer 242b of the outer portion 320 has the lower structure in which the black matrix 222 is formed. As it is formed on, it is formed higher by the thickness of the black matrix 222.

Subsequently, as illustrated in FIG. 4D, a transmissive conductive film is formed on the entire structure including the column spacers 242a and 242b and patterned to form a common electrode 252. In this case, indium tin oxide (ITO) or indium zinc oxide (IZO) may be used as the light transmissive conductive film.

As described above, the color filter substrate 200 according to the present exemplary embodiment has formed column spacers 242a and 242b on the overcoat layer 232, but is not limited thereto. The black matrix 212, the color filter 222, It can be formed on any one of the overcoat film 232 and the common electrode 252.

Subsequently, although not shown, rubbing treatment is performed by applying an alignment layer (not shown) to the two substrates 100 and 200 to align the liquid crystal molecules, and a thermosetting resin or an ultraviolet curable resin along the edge of one substrate. After applying a sealant (sealent) to form a frame-shaped seal line (seal line), and then heat-compression bonding the two substrates (100,200), injecting the liquid crystal through the opening of the seal pattern and then performing a cell process of sealing To produce a liquid crystal display device. Of course, the liquid crystal layer may also be formed through a liquid crystal dropping method other than the liquid crystal injection method described above.

In the liquid crystal display manufactured by the above method, the formation height of the column spacers 242a and 242b is controlled by the black matrix 212 so that the outer portion 320 of the effective region 300 has a higher cell gap than the central portion 310. Will have Due to such a cell gap difference, the decrease in the sal gap generated as the substrate is dripped from the central portion 310 of the effective region 300 to the outer portion 320 is canceled, resulting in a uniform cell gap throughout the entire region. Therefore, various screen defects due to the cell gap difference, for example, border screen unevenness does not occur.

Second Embodiment

Next, a liquid crystal display according to a second embodiment of the present invention will be described. In this case, a description overlapping with the above-described embodiment will be omitted or briefly described.

FIG. 5 is a cross-sectional view of a liquid crystal display according to a second exemplary embodiment of the present invention, illustrating unit pixels formed at points A and B of FIG. 1. Here, area A means a central portion of the effective area, and area B means an outer portion of the effective area.

Referring to FIG. 5, the liquid crystal display includes a thin film transistor substrate 100, a color filter substrate 200, and a liquid crystal layer formed between the two substrates 100 and 200, and formed between the two substrates 100 and 200. A plurality of column spacers 242 are formed in the effective region so that the cell gap is kept constant.

The column spacer 242 is formed using the same material, and is formed to have the same thickness and have the same height, but due to the underlying structure, the overall height depends on the formation position, and the overall height is formed in the color Controlled by filter 222. That is, the column spacer 242a of the central portion 310 is formed on a lower structure in which two adjacent color filters 222a and 222b are separated from each other so that the color filter layer is not formed. 242b is formed on a lower structure in which a portion of two adjacent color filters 222c and 222d overlap each other, and thus is formed higher by the thickness of the two overlapped color filter layers 222c and 222d. Due to the height difference between the column spacers 242a and 242b, the cell gap h ₄ of the unit pixel formed in the outer portion 320 is larger than the cell gap h ₃ of the unit pixel formed in the central portion 310 of the effective region (h). ₃ <h ₄ ) formed.

The manufacturing process of the liquid crystal display device according to the first embodiment of the present invention having such a configuration will be described below. At this time, the manufacturing process of the thin film transistor substrate 100 is the same as in the case of the first embodiment described above and will be omitted.

6 is a cross-sectional view illustrating a manufacturing process of a color filter substrate according to a second exemplary embodiment of the present invention.

First, as shown in FIG. 6A, a black matrix light blocking film is coated on a predetermined substrate 200, and then patterned to form a black matrix 212 arranged in a lattice form. In this case, it is preferable that all of the black matrices 212a and 212b are formed on the region where the column spacers 242a and 242b are to be formed.

Subsequently, as shown in FIG. 6B, an organic film for a color filter is coated on the entire structure including the black matrix 212 and then patterned thereon, whereby the black matrix 212 and a portion thereof overlap each other. G and B color filters 222 are sequentially formed. In this case, it is preferable that the color filters 222a and 222b are not formed in the corresponding region of the column spacer 242a to be formed in the central portion 310 of the effective region 300, and the outer portion 320 of the effective region 300 is not formed. It is preferable that a part of two adjacent color filters 222c and 222d overlap each other in a corresponding region of the column spacer 242b to be formed in the second spacer.

Subsequently, as shown in FIG. 6C, an overcoat layer 232 is formed on the entire structure including the color filter 222, a light-transmitting organic layer is coated thereon, and then patterned to form a column spacer 242a for maintaining a cell gap. 242b). At this time, the column spacer 242a of the central portion 310 is formed on a lower structure in which two adjacent color filters 222a and 222b are separated from each other, and thus the color filter layer is not formed. 242b is formed on a lower structure in which a portion of two adjacent color filters 222c and 222d overlap each other, and thus is formed higher by the thickness of the two overlapped color filter layers 222c and 222d.

Subsequently, as illustrated in FIG. 4D, a transmissive conductive film is formed on the entire structure including the column spacers 242a and 242b and patterned to form a common electrode 252. In this case, indium tin oxide (ITO) or indium zinc oxide (IZO) may be used as the light transmissive conductive film.

Of course, the color filter substrate 200 according to the present exemplary embodiment may form the column spacers 242a and 242b on the overcoat layer 232, but is not limited thereto. The black matrix 212, the color filter 222, The thin film may be formed on any one of the overcoat layer 232 and the common electrode 252.

Meanwhile, in the above-described first and second embodiments, either one of the black matrix or the color filter is selectively used to control the cell gap, but the present invention is not limited thereto. The black matrix and the color filter may be adjusted to adjust the cell gap to a greater width. You can also use all of them. In addition, in the above-described second embodiment, both adjacent color filters are used to control the cell gap, but the present invention is not limited thereto, and any one of two adjacent color filters may be selectively used to adjust the cell gap to a smaller width. It may be.

As mentioned above, although this invention was demonstrated with reference to the above-mentioned Example and an accompanying drawing, this invention is not limited to this, It is limited by the following claims. Therefore, it will be apparent to those skilled in the art that the present invention may be variously modified and modified without departing from the technical spirit of the following claims.

As described above, in the present invention, the formation height of the column spacer is adjusted by the lower structure formed by at least one of the black matrix and the color filter, so that the outer edge of the liquid crystal display has a cell gap higher than the center. Due to such a cell gap difference, a decrease in the sal gap generated as the substrate is dripped from the center to the outer portion of the liquid crystal display device is canceled, and as a result, the sal gap is uniformly maintained throughout the entire region. Therefore, various screen defects do not occur due to the cell gap difference.

In addition, since the cell gap of the liquid crystal display may be adjusted by using a mask process for forming a black matrix and a color filter without adding a separate mask process, the manufacturing cost may be reduced.

Claims (14)

In the color filter substrate in which the effective region is divided into a center region and an outer region, A plurality of first column spacers formed in the central region; A plurality of second column spacers formed in the outer region; The second column spacer is formed on a lower structure formed of at least one of the black matrix and the color filter, the color filter substrate, characterized in that formed higher than the first column spacer. The method according to claim 1, And the first column spacer is formed on a lower structure on which the black matrix is not formed, and the second column spacer is formed on a lower structure on which the black matrix is formed. The method according to claim 1, And the first column spacer is formed on a lower structure in which the color filter is not formed, and the second column spacer is formed on a lower structure in which the color filter is formed. The method according to claim 1, And the first column spacer is formed on a lower structure in which the color filter is formed in a single layer, and the second column spacer is formed on a lower structure in which the color filter is formed in multiple layers. The method according to claim 4, The first column spacer is formed on a lower structure in which two adjacent color filters are separated from each other and formed in a single layer, and the second column spacer is formed on a lower structure formed in a multi-layered structure by overlapping two adjacent color filters. Color filter substrate. In the manufacturing method of the color filter substrate in which the black matrix and the color filter were formed on the board | substrate, Forming a plurality of first column spacers and a plurality of second column spacers in a central region and an outer region of the substrate, The step may include forming the second column spacer on the lower structure formed of at least one of the black matrix and the color filter, thereby forming the second column spacer higher than the first column spacer. Method of preparation. The method according to claim 6, The first column spacer is formed on the lower structure on which the black matrix is not formed, and the second column spacer is formed on the lower structure on which the black matrix is formed. The method according to claim 6, And the first column spacer is formed on a lower structure in which the color filter is not formed, and the second column spacer is formed on a lower structure in which the color filter is formed. The method according to claim 6, And the first column spacer is formed on a lower structure in which the color filter is formed in a single layer, and the second column spacer is formed on a lower structure in which the color filter is formed in multiple layers. The method according to claim 6, The first column spacer is formed on a lower structure in which two adjacent color filters are separated from each other and formed in a single layer, and the second column spacer is formed on a lower structure formed in a multilayer by overlapping two adjacent color filters. Method of manufacturing a color filter substrate. A liquid crystal display in which an effective area is divided into a center area and an outer area, A plurality of first column spacers formed in the central region; A plurality of second column spacers formed in the outer region, The second column spacer is formed higher than the first column spacer. The method according to claim 11, And the second column spacer is formed on a lower structure formed of at least one of a black matrix and a color filter. The method according to claim 11, And the first column spacer is formed on a lower structure on which the black matrix is not formed, and the second column spacer is formed on a lower structure on which the black matrix is formed. The method according to claim 11, And the first column spacer is formed on a lower structure in which the color filter is not formed, and the second column spacer is formed on a lower structure in which the color filter is formed.

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