KR20040038232A - CF substrate for LCD and methode for fabricating the same - Google Patents

Abstract

PURPOSE: A color filter substrate for an LCD device is provided to comprise a spread film, a compensation film, and a polarizing film inside, and to configure thin optical films, thereby improving contrast and an angular field as manufacturing a thin LCD device. CONSTITUTION: An upper substrate(100) is a color filter substrate. A lower substrate(200) is a TFT array substrate. The first and second substrates(100,200) cohere together. On inward side of the upper substrate(100), a polarizing film(102), a compensation film(104), a spread film(106), an over coating layer(108), black matrices(110), color filters(112a-112c), a planarization film(114), and a transparent common electrode are sequentially deposited. On inward side of the lower substrate(200) corresponding to the upper substrate(100), thin film transistors(T), array wires, and transparent pixel electrodes(210) are sequentially disposed. The thin film transistors(T) have a gate electrode(202), an active layer(204), and source/drain electrodes(206,208) in order. The pixel electrodes(210) are contacted with the drain electrode(208), and are independently configured every pixel area(P).

Description

Color filter substrate for liquid crystal display and its manufacturing method {CF substrate for LCD and methode for fabricating the same}

The present invention relates to a transmissive liquid crystal display device including an in-cell optical film.

With the recent development of the information society, the necessity of flat panel displays having excellent characteristics such as thinning, light weight, and low power consumption has emerged. Among them, liquid crystal displays have a resolution and color. It is excellent in display and image quality, and is actively applied to notebooks and desktop monitors.

Currently, active matrix LCDs (AM-LCDs) in which thin film transistors and pixel electrodes connected to the thin film transistors are arranged in a matrix manner have attracted the most attention due to their excellent resolution and ability to implement video.

The liquid crystal display device includes a color filter substrate (upper substrate) on which a common electrode is formed, an array substrate (lower substrate) on which a pixel electrode is formed, and a liquid crystal filled between the upper and lower substrates. And a method in which the liquid crystal is driven by an electric field applied up and down by the pixel electrode, and has excellent characteristics such as transmittance and aperture ratio.

The alignment direction of the liquid crystal is changed by the vertical electric field, thereby adjusting the amount of light irradiated from the light source to display an image.

Various methods for realizing a high brightness and a wide viewing angle have been proposed for the liquid crystal display device configured as described above, and a structure for constituting a diffusion film inside the substrate has been proposed.

1 is a cross-sectional view schematically illustrating a configuration of a transmissive color liquid crystal display device according to the related art.

The transmissive color liquid crystal display device 10 includes a liquid crystal panel 12 including a diffusion film 22 therein and a backlight 70 under the liquid crystal panel 12.

The liquid crystal panel 12 is formed by bonding the first substrate 20, which is a color filter substrate, and the second substrate 40, which is a thin film transistor array substrate, with the liquid crystal layer 50 interposed therebetween.

It is assumed that the liquid crystal layer 50 uses a twisted nematic liquid crystal (TN LC).

(In this case, a polarizing film is formed on the upper and lower portions of the liquid crystal panel, respectively, and the polarizing film is configured such that the polarization axes are perpendicular to each other.)

The first substrate 20 includes a diffusion film 22, an over coating layer 24, a black matrix BM 26, and sub-color filters 28a, 28b, 28c, a planarization film 30 on the sub color filters 28a, 28b, and 28c, and a transparent common electrode 32 on the planarization film 30 are sequentially formed.

In the above-described configuration, the refractive index difference Δn between the diffusion film 22 and the overcoating layer 24 has a value of 0.2 or more.

On one surface of the second substrate 40 facing the first substrate 20, a data line (not shown) and a gate line (not shown) connected to the thin film transistor T and crossing each other to define pixels are formed. The transparent pixel electrode 42 connected to the thin film transistor T is independently configured for each of the pixels P. Referring to FIG.

The first polarizing film 46 and the second polarizing film 48 are formed on the outer surfaces of the first substrate 20 and the second substrate 40 so that the polarization axes are perpendicular to each other.

In this case, a retardation film 43 is further formed between the first linear polarizer 46 and the upper substrate 20.

In the above-described configuration, the diffusion film 22 is manufactured by casting a pattern formed by using a hologram method and then transferring it to an organic material applied on a substrate to form a hologram pattern on the organic material.

Such a hologram diffusion film has a characteristic of refracting light incident by the interference pattern of the hologram in an asymmetrical direction thereof.

That is, the hologram diffusion film 22 functions to diffuse light at a more inclined angle before light is emitted to the outside of the liquid crystal panel 12.

Therefore, the light irradiated through the backlight 70 is emitted to the outside of the liquid crystal panel 12 through the liquid crystal layer 50, the color filter layers 28a, 28b, 28c, and the diffusion film 22. The diffusion film 22 evenly spreads the light passing through the color filter layers 28a, 28b, and 28c to the entire surface of the liquid crystal panel 12.

The diffused light is emitted through the compensation film and the polarizer on the upper substrate.

Hereinafter, a method of manufacturing a color filter substrate for a transmissive color liquid crystal display device according to the related art will be described with reference to the drawings.

2A to 2D are cross-sectional views illustrating a conventional manufacturing process of a color filter substrate for a color liquid crystal display device according to a process sequence.

First, as shown in FIG. 2A, the diffusion film 22 is formed by applying an organic material to the entire surface of the substrate 120 in which the plurality of pixels P are defined. As described above, the hologram method is used. After casting the formed pattern is transferred to the organic material applied on the substrate to form a hologram pattern transferred to the organic material.

Subsequently, the overcoat layer 24 is formed by applying or coating a transparent organic material on the diffusion film 22.

In this case, the refractive index of the overcoating layer 24 is larger than that of the diffusion film, and the refractive index difference Δn of these two layers is preferably 0.2 or more.

Next, as shown in FIG. 2B, a black matrix 26 is formed in correspondence with the periphery of the pixels P in the entire surface of the substrate 20 on which the overcoating layer 24 is formed. The black matrix may be formed of an opaque polymer material or a bilayer of chromium (Cr) / chromium oxide (CrO _X ).

Subsequently, the sub color filters 28a, 28b, and 28c which display red (R), green (G), and blue (B), respectively, correspond to the pixel (P) on which the black matrix 26 is not formed. To form.

Next, as shown in FIG. 2C, the planarization film 30 is formed by depositing a transparent insulating material on the entire surface of the substrate 20 on which the black matrix 26 and the sub color filters 28a, 28b, and 28c are formed. After the formation, one selected from the group of transparent conductive metal materials including indium tin oxide (ITO) and indium zinc oxide (IZO) on the planarization layer 30 is deposited and patterned to form the common electrode 32. To form.

When the above-described process is completed, the thin film transistor array substrate is bonded to form a liquid crystal panel. As shown in FIG. 2D, the upper part of the substrate 20, that is, the color filter and other components are formed in a subsequent process. On the opposite side of the face, the compensating film 43 and the polarizing film 46 are sequentially formed in an adhesive manner.

In the above-described configuration, the configuration of the polarizing film will be described with reference to FIG. 3. As illustrated, the polarizing film 46 includes a protective film 46a exposed to the outside and an upper portion of the protective film 46. The first adhesive layer 46b, the polarizing layer 46c adhered by the first adhesive layer 46a and exhibiting polarization characteristics, and the second adhesive layer 46d are coated on the polarizing layer 46c.

Since the second adhesive layer 46d is a part attached to the substrate 20, the second adhesive layer 46d is configured not to be exposed to the outside through a separate protective tape 46e before being attached to the substrate.

As described above, not only the polarizing film but also the retardation film may be manufactured in a similar configuration. Since the thickness of the adhesive film is usually very thick (a few mm), it is difficult to manufacture a thin liquid crystal panel, There is a problem that such poor adhesion is likely to occur.

In addition, as described above, the externally attachable film, as the light passing through the diffusion film passes through the optical path as much as the upper substrate (700 μm in thickness), causes some scattering or interference, and thus the polarization characteristic passes through the liquid crystal. It may not be maintained.

That is, in the case of a normally black state (NB state), since a clear black cannot be implemented, a problem of low contrast ratio occurs.

The present invention has been proposed for the purpose of solving the above problems, and constitutes the polarizing film and the compensation film inside the liquid crystal panel.

In this case, since the thickness of the polarizing film and the compensation film is significantly reduced, it is possible to manufacture a thin liquid crystal panel, and since the polarizing state of the light passing through the liquid crystal is maintained, it passes through the compensation film and the polarizing film. You can implement black or white.

Therefore, a high quality liquid crystal panel can be manufactured by raising contrast ratio.

1 is a cross-sectional view schematically showing the configuration of a liquid crystal display device;

2A through 2D are cross-sectional views illustrating a manufacturing process of a conventional color filter substrate for a liquid crystal display device according to a process sequence;

3 is a cross-sectional view showing the microstructure of the polarizing film,

4A to 4D are cross-sectional views illustrating a manufacturing process of a color filter substrate for a liquid crystal display device according to a first embodiment of the present invention, in order of process;

5 is a schematic cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention;

6A to 6D are cross-sectional views illustrating a manufacturing process of a color filter substrate for a liquid crystal display device according to a second embodiment of the present invention, in order of process;

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

<Description of Symbols for Main Parts of Drawings>

100: upper substrate 102: polarizing film

104: compensation film 106: diffusion film

108: overcoating layer 110: black matrix

112a, 112b, 112c: red, green and blue sub color filters

114: planarization layer 116: common electrode

200: lower substrate 202: gate electrode

204: active layer 206,208: source and drain electrodes

210: pixel electrode

According to an aspect of the present invention, a liquid crystal display device includes: a first substrate and a second substrate on which a plurality of pixels are defined; A thin film transistor configured on one surface of the second substrate facing the first substrate; A transparent pixel electrode connected to the thin film transistor and configured in the pixel; A first polarizing film formed on one surface of the first substrate facing the second substrate; A compensation film formed on the polarizing film; A diffusion film formed on the compensation film; An over coating layer formed on the diffusion film; A black matrix and a red, green, and blue sub color filter formed on the overcoating layer; A transparent common electrode formed on the black matrix and the sub color filter; A second polarizing film formed on the other surface of the second substrate; And a liquid crystal layer positioned between the first and second substrates.

The liquid crystal layer may be made of twisted nematic liquid crystal.

In some cases, a planarization layer, which is an insulating layer, is further formed between the black matrix and the color filter and the common electrode.

The difference in refractive index between the diffusion film and the overcoating layer is characterized in that more than 0.2.

The sub color filter and the black matrix may be configured between the compensation film and the diffusion film.

According to an aspect of the present invention, a color filter substrate for a liquid crystal display device includes: a substrate in which a plurality of pixels are defined; A first polarizing film formed on one surface of the substrate; A compensation film formed on the polarizing film; A diffusion film formed on the compensation film; An over coating layer formed on the diffusion film; A black matrix and a red, green, and blue sub color filter formed on the overcoating layer; It includes a transparent common electrode formed on the black matrix and the sub color filter.

The sub color filter and the black matrix may be configured between the compensation film and the diffusion film.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First Embodiment

A feature of the first embodiment of the present invention is to sequentially configure the polarizing film and the retardation film between the substrate and the diffusion film.

Hereinafter, a manufacturing process of a color filter substrate for a liquid crystal display device according to a first embodiment of the present invention will be described with reference to the drawings.

4A to 4D are cross-sectional views illustrating a manufacturing process of a color filter substrate for a liquid crystal display device according to the present invention, in order of process.

First, as shown in FIG. 4A, the polarizing film 102 and the retardation film 104 are sequentially formed on the substrate 100.

The polarizing film 102 may be coated with a material such as PVA, or may be configured by an adhesive method, and the retardation film may also be coated with a resin (or liquid crystal monomer type retarder material) having anisotropic properties, or The produced film can be bonded to each other.

In this case, when the polarizing film 102 and the compensation film 104 are configured in an adhesive manner, unlike the conventional method, the polarizing film 102 and the compensation film 104 are not exposed to the outside.

In addition, the coating method can control the thickness as much as possible.

Therefore, the polarizing film 102 and the compensation film 104 has an advantage that can significantly reduce the thickness.

Next, as shown in FIG. 4B, the diffusion film 106 is formed on the entire surface of the substrate 100 on which the polarizing film 102 and the compensation film 104 are formed.

As described above, the diffusion film is formed by casting a pattern formed by using a hologram method and then transferring the holographic pattern to the organic material coated on the substrate to form the hologram pattern.

Next, as shown in FIG. 4C, an overcoat layer 108 is formed on the entire surface of the substrate 100 on which the diffusion film 106 is formed. The overcoat layer 108 uses a transparent resin (typically a fluorine resin) having a difference in refractive index from the diffusion film 106 having a value of about 0.2.

Subsequently, the black matrix 110 is formed in a portion of the substrate 100 on which the overcoat layer 108 is formed, corresponding to the periphery of the pixel region.

The black matrix 110 may be formed by coating (coating) an opaque resin or by depositing a multilayer of chromium / chromium oxide (Cr / CrO _X ) and patterning the same.

Subsequently, the color matrix is applied to the entire surface of the substrate 100 on which the black matrix 110 is formed, and then patterned, and the color filters of red, green, and red color corresponding to the plurality of pixel areas are sequentially performed. 112a, 112b, 112c.

As shown in FIG. 4D, a transparent organic insulating material group including benzocyclobutene (BCB) and an acrylic resin on the entire surface of the substrate 100 on which the black matrix 110 and the sub color filters 112a, 112b, and 112c are formed. The planarization layer 114 is formed by applying or coating one selected from the group.

Subsequently, indium tin oxide (ITO) or indium zinc oxide (IZO) is deposited on the planarization layer 114 to form a transparent common electrode 116.

Through the above-described process, the color filter substrate for the liquid crystal display device according to the first embodiment of the present invention can be manufactured.

5 is a cross-sectional view schematically illustrating a liquid crystal display including a color filter substrate fabricated as described above.

As shown, the liquid crystal panel according to the first embodiment of the present invention is formed by bonding the upper substrate 100 which is a color filter substrate and the lower substrate 200 which is a thin film transistor array substrate, and the upper substrate 100. Inside, the polarizing film 102, the compensation film 104, the diffusion film 106, the overcoating layer 108, the black matrix 110, the color filters 112a, 112b, 112c and the planarizing film 114 are transparent. The common electrode 116 is sequentially configured.

The inner surface of the lower substrate 200 corresponding to the upper substrate 100 includes a thin film transistor T, an array wiring (not shown), and a transparent pixel electrode 210. The thin film transistor T includes a gate electrode. The 202, the active layer 204, and the source and drain electrodes 206 and 208 are sequentially formed, and the pixel electrode 210 is in contact with the drain electrode 208, and is configured independently of each other in the pixel region P. FIG. .

After bonding the upper substrate 100 and the lower substrate 200 configured as described above, the liquid crystal is injected into the space to form the liquid crystal layer 130.

Unlike the conventional liquid crystal display device manufactured as described above, the polarizing film 102 and the compensation film 104 may be formed inside the liquid crystal panel without being attached to the outside of the liquid crystal panel to prevent defects caused by foreign substances or lifting defects. Can improve the yield.

In addition, when the films 102 and 104 are used as an adhesive method, the protective film and at least one adhesive layer described with reference to FIG. 3 may be omitted, and the film thickness may be easily controlled even when the film is formed by a coating method. It is possible to form the transistor thin.

In addition, the contrast ratio can be improved, thereby producing a high-quality liquid crystal display device.

Modifications of the invention according to the first embodiment manufactured as described above will now be described with reference to the second embodiment.

-Second Example-

A second embodiment of the present invention is characterized in that the diffusion film and the overcoating layer are formed on the color filter in the first embodiment.

Hereinafter, a manufacturing process of a color filter substrate for a liquid crystal display device according to the present invention will be described with reference to the drawings.

6A through 6D are cross-sectional views illustrating a process sequence according to the present invention.

First, as illustrated in FIG. 6A, the polarizing film 302 and the compensation film 304 are sequentially formed on the substrate 300 on which the plurality of pixels P are defined.

The polarizing film 302 may be formed by coating a material such as PVA, or by an adhesive method, and the compensation film 304 may be formed by coating a resin having anisotropic properties or by bonding an already manufactured film. .

In this case, when the polarizing film 302 and the compensation film 304 are configured in an adhesive method, since the polarizing film 302 and the compensation film 304 are not exposed to the outside, the protective film described in FIG. 3 and the adhesive layer for bonding the same do not exist. In the case of forming the coating method, since the thickness is very easy to control, the polarizing film 302 and the compensation film 304 have an advantage of significantly reducing the thickness.

Next, as shown in FIG. 6B, a black matrix 306 is formed in a portion of the upper portion of the compensation film 304 that corresponds to the circumference of the pixel region P. Referring to FIG.

The black matrix 306 may be formed by coating (or coating) an opaque resin or by depositing a multilayer of chromium / chromium oxide (Cr / CrO _X ) and patterning the same.

Subsequently, the color matrix is coated on the entire surface of the substrate 300 on which the black matrix 306 is formed, and then patterned is sequentially performed to correspond to the plurality of pixel regions P. The color filters are patterned in any order to form sub color filters 308a, 308b, and 308c.

As shown in FIG. 6C, a diffusion film 312 is formed on the entire surface of the substrate 300 on which the black matrix 306 and the sub color filters 308a, 308b, and 308c are formed.

As described above, the diffusion film 312 is formed by casting a pattern formed by using a hologram method, and then transferring the holographic pattern to an organic material coated on the substrate to form the hologram pattern.

Next, an overcoat layer 314 is formed on the entire surface of the substrate 300 on which the diffusion film 312 is formed. The overcoat layer 314 uses a transparent resin (generally a fluorine resin) having a difference in refractive index from the diffusion film 312 having a value of about 0.2.

Next, as shown in FIG. 6D, an indium tin oxide (ITO) or an indium zinc oxide (IZO) is deposited on the overcoat layer 314 to form a transparent common electrode 316.

In this process, by forming the diffusion film 312 and the overcoating layer 314 on the color filters 308a, 308b, and 308c, the planarization layer can be omitted compared to the first embodiment. There is an advantage to increase.

Through the above-described process, the color filter substrate for the liquid crystal display device according to the second embodiment of the present invention can be manufactured.

7 is a cross-sectional view schematically illustrating a liquid crystal display device including the manufactured color filter substrate as described above.

As shown, the liquid crystal panel according to the second embodiment of the present invention is formed by bonding the upper substrate 300, which is a color filter substrate, and the lower substrate 400, which is a thin film transistor array substrate, to form the upper substrate 300. Inside of the polarizing film 302, the retardation film 304, the black matrix 306, the sub color filters 308a, 308b, 308c, the diffusion film 312, the overcoating layer 314, and the transparent common electrode 316. This is configured sequentially.

The inner surface of the lower substrate 400 corresponding to the upper substrate 300 includes a thin film transistor T, an array wiring (not shown), and a transparent pixel electrode 410. The thin film transistor T includes a gate electrode. The 402, the active layer 404, and the source and drain electrodes 406 and 408 are sequentially formed, and the pixel electrode 410 is configured to contact the drain electrode 408.

After bonding the upper substrate 300 and the lower substrate 400 configured as described above, the liquid crystal is injected into the space to form the liquid crystal layer 500.

The second embodiment as described above has the same advantages as the first embodiment described above.

In the case of the first and second embodiments described above, by configuring the compensation film inside the liquid crystal panel, when the normal state is a black state, a clear black state can be exhibited at a wide viewing angle, and a separate compensation film is formed on the lower substrate. The same effect can be obtained.

Therefore, in order to further improve the contrast characteristics, there is an advantage that it is not necessary to configure a separate compensation film on the lower substrate.

Therefore, the liquid crystal display device according to the present invention has an effect of manufacturing a thin liquid crystal panel because the optical film is configured inside the liquid crystal panel.

Second, since the optical film is configured inside, there is an effect of improving the yield by removing the adhesion failure or lifting phenomenon by the foreign matter.

Third, by constructing the optical film therein, the light passing through the liquid crystal passes directly through the compensation film and the polarizing film while maintaining the polarization state. The contrast characteristics are improved, and thus the liquid crystal panel of high quality can be manufactured.

Claims (8)

A first substrate and a second substrate on which a plurality of pixels are defined; A thin film transistor configured on one surface of the second substrate facing the first substrate; A transparent pixel electrode connected to the thin film transistor and configured in the pixel; A first polarizing film formed on one surface of the first substrate facing the second substrate; A compensation film formed on the polarizing film; A diffusion film formed on the compensation film; An over coating layer formed on the diffusion film; A black matrix and a red, green, and blue sub color filter formed on the overcoating layer; A transparent common electrode formed on the black matrix and the sub color filter; A second polarizing film formed on the other surface of the second substrate; A liquid crystal layer positioned between the first and second substrates Liquid crystal display comprising a. The method of claim 1, And a liquid crystal layer comprising a twisted nematic liquid crystal. The method of claim 1, And a planarization layer as an insulating layer between the black matrix and the color filter and the common electrode. The method of claim 1, The difference in refractive index between the diffusion film and the overcoating layer is at least 0.2. A first substrate and a second substrate on which a plurality of pixels are defined; A thin film transistor configured on one surface of the second substrate facing the first substrate; A transparent pixel electrode connected to the thin film transistor and configured in the pixel; A first polarizing film formed on one surface of the first substrate facing the second substrate; A compensation film formed on the polarizing film; A black matrix and a red, green, and blue sub color filter formed on the compensation film; A diffusion film formed on the black matrix and the sub color filter; An over coating layer formed on the diffusion film; A transparent common electrode formed on the overcoating layer; A second polarizing film formed on the other surface of the second substrate; A liquid crystal layer positioned between the first and second substrates Liquid crystal display comprising a. A substrate in which a plurality of pixels are defined; A first polarizing film formed on one surface of the substrate; A compensation film formed on the polarizing film; A diffusion film formed on the compensation film; An over coating layer formed on the diffusion film; A black matrix and a red, green, and blue sub color filter formed on the overcoating layer; Transparent common electrode formed on the black matrix and the sub color filter Color filter substrate for a liquid crystal display device comprising a. The method of claim 6, And a difference in refractive index between the diffusion film and the overcoating layer is 0.2 or more. A substrate in which a plurality of pixels are defined; A first polarizing film formed on one surface of the substrate; A compensation film formed on the polarizing film; A black matrix and a red, green, and blue sub color filter formed on the compensation film; A diffusion film formed on the black matrix and the sub color filter; An over coating layer formed on the diffusion film; Transparent common electrode formed on the overcoating layer Color filter substrate for a liquid crystal display device comprising a.