KR100726133B1 - A color filter for LCD and method for fabricating thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and more particularly to a method of forming a color filter.

Conventionally, when the color filter is formed, a black matrix is formed at the boundary of each of the red, green, and blue sub-color filters.

However, the above-described conventional color filter requires a separate black matrix process, and thus, there is a complexity in the process, and since the surface is not flat, there is a need to construct a separate planarization film.

In order to solve the problems as described above, the present invention, while patterning each of the sub-color filter, the black matrix region is a height of about 33% ± 10% for the height of each sub-color filter using the diffraction exposure method Pattern so that the color filter remains.

When this process is repeated, each color filter patterned at a height of about 33% ± 10% with respect to the height of each sub color filter is formed in the black matrix area so as to overlap with the height of each sub color filter. Use this as a black matrix.

In this way, not only a color filter having a flat surface can be obtained, but also the process can be simplified, and thus the yield is improved.

Description

Color filter for liquid crystal display and its manufacturing method {A color filter for LCD and method for fabricating             

1 is a view schematically showing a liquid crystal panel,

2A to 2D are cross-sectional views illustrating a conventional color filter manufacturing process according to a process sequence by cutting along II-II ′ of FIG. 1;

3 is a schematic cross-sectional view of a diffraction exposure mask used for the present invention,

4A to 4C are cross-sectional views showing a color filter manufacturing process according to the present invention.

5A and 5B are respectively a plan view and a cross-sectional view of an array substrate to which a color filter manufactured according to the present invention is applied.

<Short description of the symbols in the drawings>

116a: red sub-color filter 116b: first black matrix

118a: green subcolor filter 118b: second black matrix

120a: red sub-color filter 120b: third black matrix

122: color filter substrate 124: transparent electrode

The present invention relates to a color liquid crystal display device, and more particularly, to a manufacturing method of a color filter including a black matrix formed in a new structure.

Hereinafter, a structure and operation characteristics thereof according to the liquid crystal panel of the liquid crystal display device will be described with reference to FIG. 1.

1 is a view schematically showing a general liquid crystal panel.

As shown, the liquid crystal display includes a color filter 7 including a black matrix 6 and a sub-color filter (red, green, blue) 8 and an upper substrate on which a transparent common electrode 18 is formed on the color filter. And a lower substrate 22 having an array wiring including a pixel region P and a pixel electrode 17 formed on the pixel region, and a switching element T. The upper substrate 5 and the lower substrate are formed of the lower substrate 22. The liquid crystal 14 is filled between the substrates 22.

The lower substrate 22 is also referred to as an array substrate, and the thin film transistor T, which is a switching element, is positioned in a matrix type, and the gate wiring 13 and the data wiring 15 passing through the plurality of thin film transistors cross each other. Is formed.

The pixel area P is an area defined by the gate line 13 and the data line 15 intersecting each other. The pixel electrode 17 formed on the pixel region P uses a transparent conductive metal having relatively high light transmittance, such as indium-tin-oxide (ITO).                         

In the above-described configuration, the first method of forming the black matrix 6 is a method of depositing and patterning an opaque metal having a low reflection characteristic such as chromium, and the second method is applying a photosensitive black resin and then It is formed by exposing and etching.

The color filter 7 is constructed in the etched area of the patterned black matrix 6.

The color filter 7 may be formed by a printing method, a dyeing method, a polymer electrodeposition method, or a pigment dispersion method.

For example, the pigment dispersion method is described by repeating the process of applying, exposing and patterning a resist, which has been colored and photosensitive with a pigment prepared in advance, to red, green, and blue. It is a method of forming a color filter.

At this time, an acrylic resin or the like may be used as a material of the color filter. In order to pattern the resin, pre-bake, exposure, development, post-bake Can be patterned through the process.

Hereinafter, a manufacturing process of a conventional color filter substrate will be described with reference to FIGS. 2A to 2D.

2A to 2D are cross-sectional views illustrating a process sequence by cutting along II-II ′ of FIG. 1.

First, FIG. 2A illustrates a process of forming a black matrix.

In general, the black matrix 6 is positioned between the red / green / blue patterns, which are generally sub color filters, and passes through a reverse tilt domain formed around the pixel electrode 17 of FIG. 1. It forms in order to shield.

In general, as the material of the black matrix 6, a metal thin film such as chromium (Cr) having an optical density of 3.5 or more, or a carbon-based organic material is mainly used, and chromium (Cr) / chromium oxide ( Black matrices of two-layer films such as CrO _X ) may be used for the purpose of low reflection.

Thus, according to the purpose, any of the above-mentioned materials is used to form the black matrix 6.

At this time, the portion 17a corresponding to the pixel electrode (17 of FIG. 1) formed on the array substrate 22 of FIG. 1 is etched by a smaller area than the pixel electrode.

FIG. 2B is a view illustrating a color filter forming process using color resins having red / green / blue color.

The main component of the color resin is composed of a photopolymerizable photosensitive composition such as a photopolymerization initiator, a monomer, a binder, and an organic pigment having a red / green / blue or similar color.

First, a red, green or blue color resin having a red color is applied to the entire surface of the substrate 5 on which the black matrix 6 is formed, and then selectively exposed to a desired area. The red sub-color filter 8a is formed in this. (The order of coloring is determined by the color order of red (R), green (G) and blue (B).)

Next, a green color resin is coated on the entire surface of the substrate 5 on which the red color filter 8a is formed, and then selectively exposed to form a green color filter 8b.

Subsequently, a blue color resin is coated on the entire surface of the substrate 5 on which the red and green color filters 8a and 8b are formed and then selectively exposed to form a blue color filter 8c.

2C is a step of planarizing the surface of the substrate on which the color filter is formed. In order to planarize the substrate 5 on which the color filters 8a, 8b, and 8c are formed, a transparent resin having an insulating property is applied on the substrate 5 to form an overcoat layer 26. .

2D is a step of forming an electrode on the color filter.

In general, when the color filter substrate 5 is used as the upper substrate of the liquid crystal panel, the upper layer of the color filter substrate 5 forms the transparent electrode 18.

In this case, a common voltage flows through the transparent electrode 18, and serves to drive the liquid crystal 14 together with the pixel voltage flowing through the pixel electrode 17 formed on the array substrate 22 as shown in FIG. 1. do.

Therefore, a selected one of a transparent conductive metal group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO) having excellent transmittance is deposited on the entire surface of the substrate 5 on which the overcoat layer 26 is formed, and the pattern is deposited. Thus, a common electrode 18 is formed.

Through the process as described above, it is possible to configure a general conventional color filter substrate.

However, since the color filter manufactured according to the conventional method must use a separate planarization layer for planarizing the surface, it is used in a limited manner in the liquid crystal mode.

In addition, since a process of forming a separate black matrix is included, there is a complexity in the process and a loss of material cost.

The present invention for solving the above problems uses a diffraction exposure method when patterning the color resin. By using the diffraction exposure method, it is possible to configure each color filter of red, green, and blue at the height of each sub color filter in the black matrix region.

The present invention as described above aims to simplify the process and reduce material costs by allowing the stacked color layers to function as black matrices.

The color filter substrate according to the present invention for achieving the above object is

A substrate; A plurality of sub color filter regions and blocking regions defined on the substrate; Respective sub color filters of red, green, and blue formed in the plurality of sub color filter areas, respectively; The black matrix may be disposed in the blocking area, and may be stacked with red, green, and blue resins patterned through diffraction exposure during mask exposure at the same height as each of the sub color filters.

The blocking region is defined as an interregion between the subcolor filter regions.

A transparent electrode is further formed on the sub color filter and the black matrix.                     

A color filter substrate manufacturing method according to a feature of the present invention comprises the steps of preparing a substrate; Defining a plurality of sub color filter regions and blocking regions on the substrate; Forming respective sub color filters of red, green, and blue in the plurality of sub color filter areas, respectively; Located in the blocking area, and patterning each of the red, green and blue color resin at the same height as each of the sub-color filter through the diffraction exposure during the mask exposure, and forming a black matrix by laminating them.

And defining the blocking area as an area between each of the subcolor filter areas.

The method may further include forming a transparent electrode on the sub color filter and the black matrix.

The color filter substrate is coated with a color resin on a substrate defined as the pixel region and the blocking region, and then exposed with a diffraction exposure mask to selectively form a sub color filter in the pixel region, and the sub region in the blocking region. The process of forming the color filter at a height of about 33% ± 10% of the height of the color filter is repeated by red, green, and blue colors.

The diffraction exposure mask is defined as a transmission region for transmitting light, a shielding region for blocking light, and a transflective region for transmitting only a predetermined amount of light.

The shielding area of the mask corresponds to the pixel area of the substrate, and the transflective area corresponds to the blocking area of the substrate.                     

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

Example

3 is a cross-sectional view of a photomask for exposing a color filter according to the present invention.

As shown in the drawing, in order to selectively expose the applied color resin for each region, a shielding area is provided on the mask substrate 110 for the transparent region A for removing the color resin, and a portion corresponding to the region leaving the color resin. The area B is constituted. (Because it uses positive color resin.)

A slit or semi-transmissive film is formed in the portion corresponding to the black matrix region defined between the sub-color filter and the sub-color filter to form the semi-transmissive region (C). An example of forming a slit pattern in a region will be described.The slit pattern functions to diffract incident light to reduce the intensity of light incident on the specimen.)

The semi-transmissive region C is a region in which light intensity is lowered to about 2/3 compared to the transmissive region A and is incident.

Therefore, the black matrix region may have a result of leaving the color resin at about 1/3 height (33% ± 10%) with respect to the height of the sub color filter.

Hereinafter, a manufacturing process of the color filter using the mask of FIG. 3 will be described with reference to FIGS. 4A to 4C.

First, as illustrated in FIG. 4A, a plurality of pixel areas D and a blocking area E existing between the pixel areas are defined on the substrate 112.

Next, a photosensitive color resin 114 having positive characteristics is coated on the entire surface of the substrate 112.

The color resin having the positive characteristic has a property that the lighted part is melted away by the solvent.

Therefore, when the process of positioning and exposing the mask 110 described above with reference to FIG. 3 on the substrate 112 on which the color resin 114 is coated on the entire surface is performed, the transparent region A of the mask 110 is formed. Both the corresponding portion A` and the portion C` corresponding to the semi-transmissive region C have a result of exposing only a predetermined depth from the surface.

In such a state, when it is developed later, all the exposed portions are removed.

As a result, a red sub color filter 116a is formed in a portion corresponding to the shielding area (B of FIG. 3), and 33% ± 10% of the height of the red color filter in the defined blocking area E. A red color filter 116b having a high degree of precision (hereinafter referred to as " first BM " for the convenience of description, and a similar configuration is also referred to as " second BM, third BM ").

Next, as shown in FIG. 4B, after applying the green color resin to the entire surface of the substrate 112 including the red sub color filter 116a and the first black matrix (116B), respectively. The mask 110 is positioned on the substrate 112.

After the mask 110 is positioned and subjected to exposure, the green sub-color filter 118a and the second BM are disposed in the portion corresponding to the shielding area B of the mask and the portion corresponding to the transflective area C. 118b remains respectively.

In this case, the height of the color resin 118b left in the portion corresponding to the semi-transmissive region C of the mask is defined as about 33% ± 10% of the height of the green sub color filter 118a.

As a result, a structure in which the first BM 116b and the second BM 118b are stacked may be obtained in the blocking region E defined in the substrate.

By repeating the above-described color filter manufacturing process, as shown in FIG. 4C, the color filter substrate 122 having the red / green / blue sub-color filters 116a, 118a, and 120a may be formed.

At this time, the color filters 116b, 118b and 120b corresponding to a height of about 30% of the height of the original color filter are overlapped between the red / green / blue color filters 116a, 118a and 120a. You can get this and use it in place of the Black Matrix.

That is, when light passes through the stacked region, the effect of the existing black matrix can be obtained as it is.

Next, a transparent common electrode 124 is deposited by depositing one selected from a group of transparent conductive metals including indium tin oxide (ITO) and indium zinc oxide (IZO) on the entire surface of the substrate 122 including the color filter. To form.

Through the process as described above, it is possible to manufacture a color filter substrate according to the present invention.                     

The color filter substrate manufactured as described above may be maximized when applied to an array substrate including a color filter in addition to the structure formed on the upper substrate.

That is, the color filter may be configured on the substrate on which the thin film transistor is formed or on the bottom of the thin film transistor.

Hereinafter, an array substrate having a thin film transistor on color filter structure to which the color filter manufacturing method according to the present invention is applied will be described with reference to FIGS. 5A and 5B.

5A and 5B are a partial plan view and a cross-sectional view of an array substrate to which a color filter manufactured according to the present invention is applied to a thin film transistor on color filter structure.

As illustrated, the gate wiring 113 and the data wiring 115 are formed to cross each other in a matrix form on the substrate 112, and at the intersection of the gate wiring 113 and the data wiring 115. The thin film transistor T is formed. The thin film transistor T includes a gate electrode 125, an active layer 119, a source electrode 121, and a drain electrode 123.

The pixel electrode 124 is formed on the entire surface of the area defined by the gate wiring 113 and the data wiring 115 intersecting, and the pixel electrode 124 is connected to the drain electrode 123 through the contact hole 127. Configure to contact.

In this configuration, a color filter unit is formed under the thin film transistor T and the pixel electrode 124, and the color filter unit is formed with red, green, and blue formed under the pixel electrode 124. each of the blue subcolor filters 116a and 118a, the gate wiring 113, the data wiring 115, and the thin film transistor T which intersect the pixel electrode in a plane, The blue color filter is composed of the black matrices 116b, 118b, and 120b stacked with the height of each sub-color filter.

A buffer layer 130 is formed on the color filter for deposition characteristics of each of the constituent layers for patterning the thin film transistor T and each wiring.

A silicon nitride film (SiN _X ) or a silicon oxide film (SiO ₂ ) is formed as the buffer layer 130.

In the array substrate configuration including the color filter as described above, there is an advantage that the planarization film for planarizing the surface of the color filter substrate does not need to be separately configured.

Therefore, the manufacturing of the color filter according to the present invention has the following characteristics.

First, since it does not form a black matrix using a separate black resin or opaque metal, there is an effect of simplifying the material cost and process.

Second, since the surface of the color filter can be planarized, it is not necessary to form an overcoat layer, which is a separate planarization film, on the color filter, which also simplifies the process and reduces material costs.

Claims (10)

A substrate; A plurality of sub color filter regions and blocking regions defined on the substrate; Respective sub color filters of red, green, and blue formed in the plurality of sub color filter areas, respectively; The black matrix, which is located in the blocking area and is stacked with the same color as each of the sub color filters, is colored with red, green, and blue color resins through diffraction exposure during mask exposure. Color filter substrate comprising a. The method of claim 1, And the blocking area is defined as an area between the sub color filter areas. The method of claim 1, And the black matrix is formed by stacking each red / green / blue resin at a height of about 33% ± 10% of the height of the sub color filter. The method of claim 1, The color filter substrate further comprising a transparent electrode on the sub color filter and the black matrix. Preparing a substrate; Defining a plurality of sub color filter regions and blocking regions on the substrate; Forming respective sub color filters of red, green, and blue in the plurality of sub color filter areas, respectively; Forming a black matrix by diffraction exposure and patterning each of the color resins of red, green, and blue at the same height as each of the sub color filters at the blocking area; Color filter substrate manufacturing method comprising a. The method of claim 5, And defining the blocking area as an area between each of the sub color filter areas. The method according to any one of claims 5 to 6, By applying an arbitrary color resin on a substrate defined as the sub color filter area and the blocking area and exposing with a mask, the sub color filter area selectively forms a sub color filter, and in the blocking area the sub color filter height And repeating the process of forming the color filter at a height of about 33% ± 10% for each red / green / blue color. The method of claim 7, wherein The mask is a method of manufacturing a color filter substrate defined by a semi-transmissive region consisting of a transmission region for transmitting light, a shielding region for blocking light, and a slit pattern for transmitting only a predetermined amount of light. The method of claim 7, And a shielding area of the mask corresponds to a sub color filter area of the substrate, and the semi-transmissive area corresponds to a blocking area of the substrate. The method of claim 6, And forming a transparent electrode on the sub-color filter and the black matrix.

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