KR102009477B1

KR102009477B1 - Method for manufacturing Liquid crystal display device

Info

Publication number: KR102009477B1
Application number: KR1020120156826A
Authority: KR
Inventors: 김상엽; 황태웅
Original assignee: 엘지디스플레이 주식회사
Priority date: 2012-12-28
Filing date: 2012-12-28
Publication date: 2019-08-09
Also published as: KR20140086395A

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device which prevents light leakage due to steps between color filters in a color filter on TFT (COT) structure in which a color filter is formed on a TFT array substrate.
A method of manufacturing a liquid crystal display device according to an embodiment of the present invention includes forming a thin film transistor in a plurality of pixel areas defined by a plurality of gate lines and a plurality of data lines; Forming a first color filter and a second color filter to cover the thin film transistor; Forming a third color filter to cover the first color filter and the second color filter; Performing a dry etch process to planarize the first color filter, the second color filter and the third color filter to the same height; Forming a pixel electrode on the first color filter, the second color filter, and the third color filter; And a protective layer covering the pixel electrode, and forming a common electrode on the protective layer.

Description

Method for manufacturing liquid crystal display device

The present invention relates to a method for manufacturing a liquid crystal display device in which light leakage due to a step between color filters is prevented in a structure in which a color filter is formed on a TFT array substrate.

Liquid crystal display devices have a wide range of applications from notebook computers, monitors, spacecrafts, aircrafts, etc. to the advantages of low power consumption and low power consumption.

The liquid crystal display device includes an upper substrate, a lower substrate, and a liquid crystal layer formed between the two substrates, and the arrangement state of the liquid crystal layer is adjusted according to whether an electric field is applied, and accordingly, the light transmittance is adjusted to display an image. to be.

Hereinafter, a liquid crystal display device according to the related art will be described with reference to the drawings.

1 and 2 are schematic cross-sectional views of a liquid crystal display device according to the prior art. 1 and 2, illustration of an upper substrate, a liquid crystal layer, and a driving circuit part of the liquid crystal display device is omitted.

1 and 2, the liquid crystal display device according to the related art includes an upper substrate (not shown), a lower substrate 1, and a liquid crystal layer (not shown) formed between the upper substrate and the lower substrate 1. It is composed.

On the glass substrate 10 of the lower substrate 1, a plurality of gate lines (not shown) and a plurality of data lines 40 are formed to cross each other to define a plurality of pixel regions, and each pixel is a TFT 30 as a switching element. thin film transistor).

In each pixel, color filters 20 of red (R), green (G), and blue (B) are formed, and a black matrix (BM: Black matrix) for preventing light leakage is formed. In addition, a column spacer (CS) for forming a cell gap with the upper substrate is formed on the black matrix BM.

The color filter 20 is formed to cover the TFT 30, and the pixel electrode 50 is formed on the color filter 20. The protective layer 60 is formed to cover the pixel electrode 50, and the common electrode 70 is formed on the protective layer 60.

In the conventional liquid crystal display device having the above-described configuration, as shown in FIG. 1, the color filter 20 is formed by overlapping pigments to prevent light leakage in an area in which the data line 40 is formed.

As illustrated in FIG. 2, after forming the common electrode 70 when manufacturing the lower substrate 1, a rubbing process is performed using the rubbing cloth 80 for the initial alignment of the liquid crystal. Here, the red (R), the green (G), and the blue (B) color filters 20 overlap, and a step occurs between the color filters 20, and particularly in an area overlapping the data line 40. Since the step of the color filter is deepened rubbing is not performed smoothly, there is a problem that light leakage occurs.

Disclosure of Invention The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a method of manufacturing a liquid crystal display device capable of preventing light leakage caused by a step between color filters.

In addition to the technical task of the present invention mentioned above, other features and advantages of the present invention will be described below, or from such description and description will be clearly understood by those skilled in the art.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, including: forming a thin film transistor in a plurality of pixel areas defined by a plurality of gate lines and a plurality of data lines; Forming a first color filter and a second color filter to cover the thin film transistor; Forming a third color filter to cover the first color filter and the second color filter; Performing a dry etch process to planarize the first color filter, the second color filter and the third color filter to the same height; Forming a pixel electrode on the first color filter, the second color filter, and the third color filter; And forming a protective layer to cover the pixel electrode, and forming a common electrode on the protective layer.

In accordance with another aspect of the present invention, a liquid crystal display device includes: a plurality of gate lines and a plurality of data lines formed to cross on a lower substrate; A plurality of thin film transistors formed in the plurality of pixel areas defined by the plurality of gate lines and the plurality of data lines; A first color filter, a second color filter, and a third color filter formed on the plurality of thin film transistors; A pixel electrode formed on the first color filter, the second color filter, and the third color filter and connected to the drain electrode of the thin film transistor; A protective layer formed to cover the pixel electrode; And a common electrode formed on the protective layer, wherein the first color filter, the second color filter, and the third color filter are formed to have the same height.

The manufacturing method of the liquid crystal display device according to the exemplary embodiment of the present invention can flatten the color filters to prevent generation of light leakage in the COT structure.

According to the present invention, since the thin film transistor, the pixel electrode, the common electrode, the color filter, and the column spacer are formed together on the lower substrate, the process line for the upper substrate facing the lower substrate can be omitted or simplified. .

In addition, other features and advantages of the present invention may be newly understood through the embodiments of the present invention.

1 and 2 are schematic cross-sectional views of a liquid crystal display device according to the prior art.
3 is a cross-sectional view of a liquid crystal display device according to an exemplary embodiment of the present invention.
4 and 5 illustrate a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention, which forms a color filter in a color filter on TFT (COT) structure.

In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components have the same number as much as possible even though they are displayed on different drawings.

On the other hand, the meaning of the terms described herein will be understood as follows.

Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and the terms “first”, “second”, etc. are used to distinguish one component from another. The scope of the rights shall not be limited by these terms.

It is to be understood that the term "comprises" or "having" does not preclude the existence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.

The term "at least one" should be understood to include all combinations which can be presented from one or more related items. For example, the meaning of "at least one of the first item, the second item, and the third item" means two items of the first item, the second item, and the third item, as well as two items of the first item, the second item, and the third item, respectively. A combination of all items that can be presented from more than one.

In describing embodiments of the present invention, when a structure is described as being formed 'on or on top' and 'under or under' another structure, these descriptions may be used to describe these structures as well as the structures in contact with each other. It should be interpreted as including even if a third structure is interposed between them.

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

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

Referring to FIG. 3, a liquid crystal display device according to an exemplary embodiment of the present invention includes an upper substrate (not shown), a lower substrate 100, and a liquid crystal layer (not shown) formed between the upper substrate and the lower substrate 100. It is configured by.

On the glass substrate 110 of the lower substrate 100, a plurality of gate lines (not shown) and a plurality of data lines 140 intersect to define a plurality of pixel regions, and the TFT 130 is a switching element for each pixel. ) Is formed.

Each pixel is formed with a color filter 120 of red (R), green (G), and blue (B), and a black matrix (BM: Black matrix) is formed to prevent light leakage. In addition, a column spacer (not shown) is formed on the black matrix BM to form a cell gap with the upper substrate.

Red (R), green (G), and blue (B) color filters 120 are formed to cover the TFTs 130, and pixel electrodes 150 are formed on the color filters 120. The passivation layer 160 is formed to cover the pixel electrode 150, and the common electrode 170 is formed on the passivation layer 160.

The gate line and the data line may be arranged in a straight straight line, or may be arranged in the form of a curved straight line. The TFT 130 is formed in a region where the gate line and the data line intersect as switching elements.

The thin film transistor T includes a gate electrode, a semiconductor layer, a source electrode, and a drain electrode. The gate electrode is branched from the gate line, the source electrode is branched from the data line, and the drain electrode is formed to face the source electrode. In FIG. 3, a bottom gate type TFT in which a gate electrode is positioned below the semiconductor layer is illustrated as an example. However, the present invention is not limited thereto, and the TFT is formed in a top gate type manner in which the gate electrode is positioned above the semiconductor layer. Can be formed.

The pixel electrode 150 is formed in each of the pixels, and the pixel electrode 150 is electrically connected to the drain electrode of the TFT 130. In particular, the pixel electrode 150 may be electrically connected to the drain electrode of the thin film transistor T through a predetermined contact hole.

The common electrode 170 is arranged on a different layer from the pixel electrode 150, and the liquid crystal is formed through a fringe field generated between the pixel electrode 150 and the common electrode 170 arranged as described above. The arrangement direction of the layers can be controlled.

The common electrode 170 is connected to a common line arranged in parallel with the gate line 11, so that a common voltage may be applied to the common electrode 170 through the common line.

Here, in the conventional COT structure, red (R), green (G), and blue (B) color filters are formed to overlap each other, but in the present invention, red (R), green (G), and blue (B). ) Color filters 120 are formed flat without overlapping each other. That is, the heights of the color filters 120 of red (R), green (G), and blue (B) are formed to be the same, and the color filters of red (R), green (G), and blue (B) ( Steps do not occur at the boundary of 120).

In addition, the color filter 120 in the region where the data line 140 is formed may also be formed to have the same height as other regions to prevent light leakage defects caused by the step of the color filter.

4 and 5 illustrate a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention, which forms a color filter in a color filter on TFT (COT) structure.

A method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3 and 5.

A gate electrode 131 is formed on the glass substrate 110, and a gate insulating layer 132 is formed on the gate electrode 131. Thereafter, a semiconductor layer 133 is formed on the gate insulating layer 132, a source electrode 134 is formed on one side of the semiconductor layer 133, and a drain electrode is formed on the other side of the semiconductor layer 133. And form 135. As a result, the TFT 130 may be formed for each pixel.

4, the color filter 120 is formed to cover the TFT 130.

First, a red color filter 120R is formed of a red pigment, and a green color filter 120G is then formed of a green pigment. At this time, the green pigment overlaps the boundary portion of the red color filter 120R, and a step occurs in the region where the red color filter 120R and the green color filter 120G overlap.

Subsequently, a blue pigment is formed to cover the red color filter 120R and the green color filter 120G. As a result, the blue color filter 120B is thickly formed to cover the red color filter 120R and the green color filter 120G.

After coating the red pigment and the green pigment (coating) to form the red color filter (120R) and green color filter (120G), the blue pigment is coated on the entire surface of the substrate to the red color filter (120R) and green color filter ( The blue color filter 120B is formed so as to cover 120G).

Subsequently, referring to FIG. 5, a dry etch process is performed on the blue color filter 120B to cover the red color filter 120R and the green color filter 120G.

The height of the blue color filter 120B covering the red color filter 120R and the green color filter 120G is lowered. Then, the green color filter 120G protruding by overlapping the boundary of the red color filter 120R is formed. Remove part of it.

As such, the dry etch process is performed to flatten the red color filter 120R, the green color filter 120G, and the blue color filter 120B to have the same height.

As a result, the heights of the red color filter 120R, the green color filter 120G, and the blue color filter 120B are all the same, and the overlapped portions can be removed from the boundary of each color filter.

Referring again to FIG. 3, after the color filter 120 is formed such that the heights of the red color filter 120R, the green color filter 120G, and the blue color filter 120B are flat, the pixel on the color filter 120 is formed. An electrode 150 is formed.

The contact hole is formed by etching the color filter 120 overlapping the drain of the TFT 130, and a transparent conductive material such as ITO is deposited on the color filter 120 and the contact hole to form a pixel electrode. 150 is formed.

Next, the protective layer 160 is formed to cover the pixel electrode 150, and the common electrode 170 is formed on the protective layer 160. Thereafter, a rubbing process using a rubbing cloth is performed.

In the liquid crystal display device according to the exemplary embodiment of the present invention manufactured by the above-described manufacturing method, the red color filter 120R, the green color filter 120G, and the blue color filter 120B formed on the lower substrate 100 are identical to each other without any step difference. It is formed to be flat at a height to facilitate the rubbing process using a rubbing cloth. Rubbing is uniformly performed on the entire lower substrate 100 to prevent light leakage.

100: lower substrate 110: glass substrate
120: color filter 120R: red color filter
120G: green color filter 120B: blue color filter
130: TFT 140: data line
150: pixel electrode 160: protective layer
170: common electrode BM: black matrix

Claims

Forming a thin film transistor in each of the plurality of pixel regions defined by the plurality of gate lines and the plurality of data lines;
Forming a first color filter corresponding to a part of the plurality of pixel areas and covering the thin film transistor corresponding to the part of the pixel area, corresponding to another part of the plurality of pixel areas, and corresponding to the other part of the pixel area Forming a second color filter covering the thin film transistor and overlapping a boundary of the first color filter;
Forming a third color filter covering the thin film transistor corresponding to another part of the plurality of pixel areas and corresponding to the other part of the pixel area and further covering the first and second color filters;
Performing a dry etch process to planarize the first color filter, the second color filter, and the third color filter to the same height;
Forming a pixel electrode on the first color filter, the second color filter, and the third color filter flattened to the same height; And
Forming a protective layer covering the pixel electrode, and forming a common electrode on the protective layer;
Performing the dry etch process to planarize the first color filter, the second color filter, and the third color filter to the same height, and through the dry etch, the first color filter and the second color filter. A method of manufacturing a liquid crystal display device which removes an overlapped portion between and an overlapped portion between each of the first and second color filters and the third color filter.

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According to claim 1,
The first color filter is a red color filter,
The second color filter is a green color filter,
And the third color filter is a blue color filter.

According to claim 1,
Forming the first color filter and forming the second color filter, coating a first pigment to form the first color filter, coating a second pigment to form the second color filter,
And forming the third color filter by coating a third pigment on the entire surface including the first and second color filters in the forming of the third color filter.

The method of claim 4, wherein
The first pigment is a red pigment,
The second pigment is a green pigment,
The third pigment is a blue pigment manufacturing method of a liquid crystal display device.

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