KR100936888B1 - Black matrix of LCD and making method of thereof - Google Patents

Abstract

A method of forming a black matrix of a liquid crystal display according to the present invention includes the steps of coating an oxide film on each of a plurality of metal particles; Mixing the plurality of metal particles coated with the oxide film with a highly volatile resin and applying the same to a color filter substrate; Forming a resin including oxide film metal particles coated on the color filter substrate in a predetermined pattern, and applying a predetermined heat to the patterned resin region to remove the resin; A step of forming only a pattern by a plurality of metal particles coated with an oxide film by removing the resin is formed on the color filter substrate.

According to the present invention, it is possible to achieve low reflection of internal / external light of the black matrix without forming a separate oxide film, and thus there is an advantage of forming a high efficiency and low cost black matrix.

Description

Black matrix of LCD and making method thereof

1 is an exploded perspective view showing a part of a conventional liquid crystal display device.

2 is a cross-sectional view of a specific area of the upper substrate shown in FIG.

3A to 3B are a plan view and a partial cross-sectional view of a color filter substrate of a liquid crystal display according to the present invention.

Figure 4 is a cross-sectional view showing a step of forming a black matrix according to the present invention.

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

5: Color Filter Substrate 6, 6 ': Black Matrix

8: sub color filter 18: common electrode

21: overcoat layer 30: metal particles

32: oxide film 34: oxide metal particles

36: Resin 38: Mixed Resin

40: patterned area

The present invention relates to a liquid crystal display device, and more particularly, to a black matrix (BM) formed on a color filter substrate of a liquid crystal display device and a method of forming the same.

Recently, liquid crystal displays (LCDs) have been widely used as devices for displaying various images including still and moving images. This is due to the characteristics such as light weight, thinness, low consumption driving, and the like, the image quality is being accelerated by the improvement of the liquid crystal material and the development of the fine pixel processing technology, and the application range is gradually increasing.

In general, the driving principle of the liquid crystal display device uses the optical anisotropy and polarization of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

Accordingly, if the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light polarized by optical anisotropy may be arbitrarily modulated to express image information.

Currently, an active matrix LCD in which a thin film transistor and pixel electrodes connected to the thin film transistor are arranged in a matrix manner is generally used because of its excellent resolution and video performance.

The structure of the liquid crystal panel, which is a basic component of the liquid crystal display, is as follows.                         

1 is an exploded perspective view showing a part of a conventional liquid crystal display device.

Referring to FIG. 1, a conventional color liquid crystal display device includes a color filter 7 including a black matrix 6 and a sub color filter (red, green, blue) 8, and a common electrode 18 transparent on the color filter. ) Is formed of an upper substrate 5 formed with the upper substrate 5 and a lower substrate 22 having an array wiring including a pixel region P, a pixel electrode 17 formed on the pixel region, and a switching element T. The liquid crystal 14 described above is filled between the substrate 5 and the lower substrate 22.

In this case, the upper substrate 5 is also referred to as a color filter substrate, and in particular, the black matrix 6 serves to distinguish between the sub color filters 8 and to block light.

In addition, the lower substrate 22 may also be referred to as an array substrate, and the thin film transistor T, which is a switching element, may be disposed in a matrix, and the gate line 13 and the data line 15 passing through the plurality of thin film transistors may be formed. do.

In addition, the pixel area P is a region where the gate line 13 and the data line 15 cross each other. The pixel electrode 17 formed on the pixel region P uses a transparent conductive metal having a relatively high transmittance of light, such as indium tin oxide (ITO).

In the liquid crystal display device 11 configured as described above, the liquid crystal layer 14 positioned on the pixel electrode 17 is oriented by a signal applied from the thin film transistor, and the liquid crystal layer depends on the degree of alignment of the liquid crystal layer. The image can be expressed by controlling the amount of light passing through the image.

That is, a desired color image is displayed while light passing through the pixel electrode 17 connected to the thin film transistor passes through each of the red, green, and blue sub color filters 8 corresponding to the pixel electrodes 17. will be.

FIG. 2 is a cross-sectional view of a specific area A-A of the upper substrate shown in FIG. 1.

Referring to FIG. 2, this is a black matrix (BM) formed between a sub color filter 8 of red, green, and blue that implements color on the upper substrate 5 and the sub color filter 8 ( 6) and a common electrode 18 for applying a voltage to the liquid crystal cell.

In addition, an overcoat layer is used by using an acrylic or polyimide resin to protect and planarize the sub color filter 8 before the common electrode 21 is formed. (21) may be formed.

In this case, the black matrix 6 serves to block light leakage. In general, the pixel electrodes positioned between the red, green, and blue patterns of the sub color filter 8 and on the lower substrate are not formed. It is formed in a portion, etc., and is formed for the purpose of shielding light leaking to the portion where the pixel electrode is not formed. In addition, the black matrix 6 serves to block the direct light irradiation of the thin film transistor to prevent an increase in leakage current of the thin film transistor.

The material of the black matrix 6 is an optical density (OD) of 3.5 or more metal thin film such as chromium (Cr), a carbon-based organic material, or a photo acryl-based resin (Resin). ) Is mainly used.

In addition, when the chromium is used as the black matrix, the black matrix is formed of a Cr / CrO _X multilayer film structure to block reflected light that adversely affects image display, that is, to reduce the reflection of the LCD screen. .

In this case, the chromium oxide film CrO _X may be formed between the substrate and the chromium film Cr to reduce the reflection of light coming from the outside of the liquid crystal display, and the substrate to reduce the reflection of light coming from the inside of the liquid crystal display. It may be formed on the chromium film Cr of the opposite side.

In addition, both the upper and lower surfaces of the chromium film Cr may be formed to reduce both reflection of the external light and the internal light.

However, when forming the black matrix as described above, the optical path calculation of the light is essential, so it is very sensitive to the refractive index of the oxide film and the thickness of each film, so that it is impossible to optimize the low reflection of all the light finally obtained. There is a disadvantage in that the incidence rate increases and manufacturing costs rise.

In addition, when the carbon-based organic material or photo acryl-based resin is used as a black matrix, the above problem can be overcome, but it is disadvantageously low in terms of cost. There is a problem with anger.

The present invention forms a black matrix pattern and removes the resin by oxidizing the surface of the metal particle and mixing it with a resin, thereby achieving low reflection of internal and external light of the black matrix without forming a separate oxide film. An object of the present invention is to provide a black matrix and a method of forming the same.

In the black matrix of the liquid crystal display device according to the present invention for achieving the above object, in the color filter substrate of the liquid crystal display device in which a transparent common electrode is formed on the black matrix and the sub color filter, the black matrix and the sub color filter, the oxide film The enclosed plurality of metal particles is patterned and formed on the color filter substrate in a lattice form.

In addition, the color filter substrate of the liquid crystal display device according to the present invention for achieving the above object, the black matrix; Red, green, and blue sub-color filters sequentially formed in the empty space of the black matrix; An overcoat layer applied to an entire surface of the black matrix and the red, green, and blue sub color filters; It includes a transparent common electrode for transmitting light to the upper surface of the overcoat layer.

In addition, a method of forming a black matrix of a liquid crystal display according to the present invention for achieving the above object comprises the steps of: coating an oxide film on each of the plurality of metal particles; Mixing the plurality of metal particles coated with the oxide film with a highly volatile resin and applying the same to a color filter substrate; Forming a resin including oxide film metal particles coated on the color filter substrate in a predetermined pattern, and applying a predetermined heat to the patterned resin region to remove the resin; Only the pattern formed by the plurality of metal particles coated with an oxide film by removing the resin is formed on the color filter substrate, wherein the predetermined heat is 300 ° C. or less.                     

According to the present invention, it is possible to achieve low reflection of internal / external light of the black matrix without forming a separate oxide film, and thus there is an advantage of forming a high efficiency and low cost black matrix.

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

3A to 3B are plan views and partial cross-sectional views of the color filter substrate of the liquid crystal display according to the present invention.

Referring to FIGS. 3A and 3B, this illustrates a black matrix formed in a lattice shape of the entire outer portion and the inside of the color filter substrate.

In the color filter substrate 5, red, green, and blue sub color filters 8 are sequentially formed in an empty space of the black matrix 6 ′, that is, an internal lattice shape, and the black matrix 6 is formed. ') And acrylic or polyimide resin (Resin) is used to protect and planarize the sub color filter (8) in front of the red, green, and blue sub color filters (8). As a result, an overcoat layer OC 21 is formed, and a transparent common electrode 18 is formed on the upper surface of the overcoat layer to form a whole.

In the present invention, unlike the prior art, the black matrix 6 'does not have a multilayer structure of Cr / CrO _X , and oxidizes the surface of the granular metal particles 30, whereby the oxide film 32 is formed. The black matrix 6 is formed using a plurality of oxide metal particles 34, respectively.

That is, the black matrix 6 ′ according to the present invention is formed by lattice patterning on the color filter substrate 5 by the plurality of oxide metal particles 34 surrounded by the oxide film 32. In addition, in the present invention, the metal particles 30 are not necessarily limited to chromium (Cr), and as the metal particles 30, Mo, Al, Ti, Ta, In, Sn, Ni, Zn, or the like may be used. have.

4 is a cross-sectional view showing a step of forming a black matrix according to the present invention.

First, each metal particle 30 in granular form is oxidized. (a)

As such, forming the oxide film 32 on each metal particle 30 is obtained by continuously injecting _{2 2} (or O ₂ + N ₂ ) into the metal particles 30 and heat-treating them. At this time, the thickness of the oxide film 32 may be adjusted according to conditions such as the amount of 2O ₂ (O ₂ + N ₂ ), temperature, time, and the like.

At this time, it is preferable to use a metal such as chromium (Cr) or molybdenum (Mo) as the metal particles 30, but is not necessarily limited thereto, and accordingly Al, Ti, Ta, In, Sn, Ni, Zn, etc. Can be used

Next, a plurality of oxide metal particles 34 coated with the oxide film 32 are mixed with a highly volatile resin 36 and mixed, and then the mixed resin 38 is applied to the color filter substrate 5. do. (b)                     

Next, a resin including the mixed resin 38, ie, oxide metal particles 34, applied to the color filter substrate 5 as a whole by a general photolithography process and an etching process. To form a constant pattern (40). (c)

Here, the photo process uses a mask of the pattern (pattern) to obtain a light by using a principle that changes the properties of the photoresist (hereinafter 'PR') when the light receives a chemical reaction occurs Is a step of forming the same pattern as the pattern of the mask by selectively irradiating to the PR, this photo process is a PR coating process for applying a photoresist corresponding to a film of a general photograph, selectively using a mask And an exposure step of irradiating the light, followed by a developing step of forming a pattern by removing the PR of the light-received portion using a developer.

Next, a predetermined heat is applied to the patterned resin region 40 to remove the resin 36. As described above, since the resin 36 is highly volatile, all of the resin 36 is removed except for the oxide metal particles 34 mixed therein under constant heat. At this time, the predetermined heat is not to exceed 300 ℃. (d)

As such, when all of the resin material 36 is removed from the patterned resin region 40, only the pattern of the plurality of oxide metal particles 34 coated with the oxide film 30 is left in the region. It becomes a black matrix 6 'formed on the color filter substrate 5. (e)

When the black matrix is formed on the color substrate by the above process, the sub color filter 8, the overcoat layer 21, and the transparent electrode 18 are sequentially formed. (f)

This is formed by the same process as the general color filter manufacturing process, looking at this as follows.

First, a red subcolor filter pigment is applied onto the color filter substrate 5 on which the black matrix 6 'is formed, and soft baked at a hot plate at 80 to 100 ° C. for a predetermined time, and then using a photo mask. Exposure / development Thereafter, the developed red sub color filter pigment is post-baked to form a red sub color filter 8 pattern in the empty space including the edge of the black matrix.

Subsequently, the green and blue sub color filter 8 patterns are formed in the empty space of the black matrix including the edge of the black matrix in the same manner as described above.

Next, a flattening protective film, that is, an overcoat layer 21, is formed to protect the black matrix 6 ′ and the sub color filter 8 pattern from external impact and external environment and to improve smoothness. After forming an organic transparent material such as acryl, polyimide, polyacrylate, polyurethane, and the like having excellent surface hardness and light transmittance to a thickness of crystal, it is heated for about 1 hour in a baking oven having a temperature of about 200 ° C. Is formed.

Finally, a transparent metal, for example, ITO, is deposited on the entire surface of the overcoat layer 21 to a thickness of 1500 Å or less to form a common electrode 18, thereby completing the color filter substrate.

As described above, according to the black matrix and the method of forming the LCD according to the present invention, it is possible to achieve low reflection of internal and external light of the black matrix without forming a separate oxide film. There is an advantage to form an efficient and low-cost black matrix.

Claims (4)

A plurality of metal particles; And And a black matrix made of an oxide film surrounding each of the metal particles. The method of claim 1, And the black matrix has a multi-layered structure formed of the plurality of metal particles and the oxide film. Forming a black matrix; Forming a red, green, and blue subcolor filter in an empty space of the black matrix; Forming an overcoat layer on an entire surface of the black matrix and the red, green, and blue subcolor filters; And Forming a common electrode on the overcoat layer, Forming the black matrix, Coating an oxide film on each of the plurality of metal particles; Mixing a plurality of metal particles coated with the oxide film with a highly volatile resin to form a mixture; Applying the mixture to a color filter substrate to form a metal particle oxide film; Patterning the metal particle oxide film; And And heat-treating the metal particle oxide film pattern to remove the resin. The method of claim 3, wherein The black matrix is a method of manufacturing a color filter substrate of a liquid crystal display device, characterized in that a plurality of metal particles coated with the oxide film is formed in multiple layers.

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