KR20050052690A - Color filter plate of lcd and manufacturing method thereof - Google Patents

Abstract

A color filter substrate manufacturing method of a liquid crystal display according to the present invention includes the steps of preparing a substrate; Forming a black matrix in a predetermined area defined on the substrate; Forming a color filter of red, green, and blue to partially overlap the black matrix; Forming an overcoat layer on the black matrix and the color filter; Compensating the stepped portion by removing the overcoat layer formed on the stepped portion formed by overlapping the black matrix and the color filter by a predetermined thickness during diffraction exposure during mask exposure.

According to the present invention, the thickness difference remaining after the leveling between the color filter and the black matrix due to the overcoat layer formation when the IPS mode liquid crystal display device color filter substrate is formed is compensated additionally, thereby improving the flatness of the overcoat layer. Thereafter, damage to the alignment layer may be minimized during the rubbing process of the alignment layer.

Description

Color filter substrate of liquid crystal display device and manufacturing method thereof

The present invention relates to a liquid crystal display device, and more particularly, to a color filter substrate of a transverse electric field type liquid crystal display device and a manufacturing method thereof.

In general, a liquid crystal display device is formed by bonding an upper substrate and a lower substrate, and injecting a liquid crystal between the upper substrate and the lower substrate. In addition, a polarizer, a retardation film, and the like are attached to the outer surfaces of the upper and lower substrates, and by selectively configuring such a plurality of components, the light propagation direction or the refractive index is changed to be high. A liquid crystal display device having brightness and contrast characteristics is formed.

The liquid crystal cell used in recent years as a liquid crystal display device generally adopts a Twisk nematic (TN) mode, and the TN mode has a characteristic that the light transmittance in the gray scale display varies depending on the viewing angle, thereby limiting its large area. have.

In order to solve this problem, an In-Plane-Switching (IPS) mode using a parallel electric field has contrast, gray inversion, and color shift compared to the conventional TN mode. There is an advantage that can improve the viewing angle characteristics such as (shift).

In the IPS mode, a pixel electrode and a common electrode are formed on the same plane on a thin film transistor (TFT) array substrate, that is, a lower substrate provided with a TFT, and a liquid crystal is formed of the pixel electrode and the common electrode formed on the same substrate. It is operated by a horizontal electric field.

1 is a cross-sectional view of a specific portion of a conventional liquid crystal display device in IPS mode.

Referring to FIG. 1, the upper substrate (or color filter substrate) 10 and the lower substrate (or array substrate) 30 are spaced apart from each other by a predetermined distance, and the liquid crystal layer between the upper and lower substrates 10 and 30. (50) is interposed.

A gate electrode 32 is formed on the transparent substrate 1 of the lower substrate 30, and a gate insulating layer 34 is formed on the gate electrode 32. The semiconductor layer 36 in which the active layer 36a and the ohmic contact layer 36b are sequentially stacked is formed at a position covering the gate electrode 32.

Source and drain electrodes 38 and 40 are formed on the semiconductor layer 36 to be spaced apart from each other by a predetermined distance, and a portion of the active layer 36a is formed in the interval between the source and drain electrodes 38 and 40. Channel is formed, and the gate electrode 32, the semiconductor layer 36, the source and drain electrodes 38 and 40, and the channel form a thin film transistor T.

In addition, a gate line (not shown) is formed in a first direction by being connected to the gate electrode 32, and the data line 41 is connected with the source electrode 38 in a second direction crossing the first direction. Is formed, and the region where the gate and the data wiring cross is defined as the pixel region P. As shown in FIG.

In addition, a passivation layer 42 having a drain contact hole 44 is formed on the thin film transistor T, and the drain electrode 40 is formed in the pixel region P through the drain contact hole 44. A pixel electrode 48 connected to each other and having a plurality of vertical patterns is formed, and a common electrode 49 having a plurality of vertical patterns staggered with a vertical pattern of a pixel electrode is formed on the same layer as the pixel electrode formed layer. Formed.

In addition, a lower alignment layer 46 is formed on the passivation layer 42 and the pixel electrode 48 / common electrode 49 to easily induce alignment of the liquid crystal layer 50.

In addition, a color filter 14 is formed below the transparent substrate 2 of the upper substrate 10 to filter only light of a specific wavelength band at a position corresponding to the pixel region P. The color filter 14 The black matrix 12 is formed at the boundary of each color to block light leakage and light inflow into the thin film transistor T. A flattening layer, ie, an overcoat, is formed below the color filter 14 and the black matrix 12. Layer 16 is formed.

In addition, an upper alignment layer 18 having the same role as the lower alignment layer 46 is formed under the overcoat layer.

In the above-described configuration, the first method of forming the black matrix 12 is a method of depositing and patterning an opaque metal having a low reflection property such as chromium, and the second method is applying a photosensitive black resin and then It is formed by exposing and etching.

In addition, the color filter 14 is formed in an etched region of the patterned black matrix 12, and the color filter 14 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.

In this case, 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, and post-bake processes may be used. Can be patterned via

2A to 2F are cross-sectional views illustrating a process of manufacturing a color filter substrate of a conventional IPS mode liquid crystal display device.

Referring to FIGS. 2A through 2F, a process of manufacturing a color filter substrate of a conventional IPS mode liquid crystal display is as follows.

First, as shown in FIG. 2A, a black matrix 12 is formed in a predetermined region on the substrate 2.

In general, the black matrix 12 is positioned between red / green / blue patterns, which are generally sub-color filters of the pixel region A, and transmits light passing through a reverse tilt domain formed around the pixel region. It forms for the purpose of shielding.

In addition, the black matrix 12 is formed on the outer portion of the liquid crystal panel, that is, on the non-display area B of the panel through which light is not transmitted.

Next, as shown in FIG. 2B, a color filter 14 using color resin having red / green / blue color is formed.

This is applied to the entire surface of the substrate 2 on which the black matrix 12 is formed by applying a color resin having a red color among red, green, and blue color resins, and then selectively exposing it to a desired area. A red sub color filter is formed. (The order of coloring is decided by the order of red (R), green (G), blue (B).)

Next, a green color resin is coated on the entire surface of the substrate 2 on which the red color filter is formed, and then selectively exposed to form a green color filter.

Subsequently, a blue color resin is coated on the entire surface of the substrate 2 on which the red and green color filters are formed, and then selectively exposed to form a blue color filter.

Next, as shown in FIG. 2C, an overcoat layer 16 is formed to planarize the surface of the substrate on which the color filter is formed.

In order to planarize the substrate 2 on which the color filter 14 is formed, a transparent resin having an insulating property is coated on the substrate 2 to form a planarization layer, that is, an overcoat layer 16.

However, in the conventional case, in forming the overcoat layer, the overcoat layer formed on the outer portion of the liquid crystal panel, that is, on the non-display area B of the panel through which light is not transmitted, is removed, which is an array substrate and a color filter. The area where the sealant adheres is included when the substrates are bonded together, and the overcoat layer is removed for reasons such as maintaining a cell gap of both substrates.

For this purpose, after the overcoat layer is applied, a photo process, that is, an exposure and development process, etc. by the photo mask 20 is required as shown in FIG. 2D, and the non-display area 20 of the panel is processed by the photo process. The overcoat layer formed in) is removed.

The overcoat layer formed on the non-display area 20 is removed in FIG. 2E.

Next, as shown in FIG. 2F, an alignment layer is formed on the overcoat layer, and rubbing is performed on the alignment layer.

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

However, according to the conventional color filter substrate, a step C is always formed in an area where the color filter 14 and the black matrix 12 overlap each other, whereby the color filter 14 and the black matrix ( Even if the overcoat layer 16 as the planarization layer is formed on the substrate 12, a slight step remains for the region where the stepped portion C is formed. As a result, the alignment layer 18 formed on the overcoat layer 16 is also formed. In the stepped region C, the curvature is provided.

Accordingly, in the process of rubbing the alignment layer 18 formed on the overcoat layer 16 as shown in FIG. 3A, the stepped region C is poor in flatness and thus damaged by rubbing cloth. ) To generate large and small alignment layer residues 24, and the alignment layer residues 24 have a problem of causing light leakage as liquid crystal domains are formed around the alignment layer residues as shown in FIG. 3B. . 3A and 3B are diagrams showing problems of the conventional color filter substrate structure.

The present invention compensates the step portion generated in the region where the color filter and the black matrix overlap by using a diffraction pattern mask during the photo process of forming the overcoat layer, thereby improving flatness of the overcoat layer and damaging the alignment layer during the rubbing process of the alignment layer. It is an object of the present invention to provide a color filter substrate and a method of manufacturing the same for a liquid crystal display device.

In order to achieve the above object, the color filter substrate of the liquid crystal display device according to the present invention includes a substrate; A black matrix formed in a predetermined area defined on the substrate; A red, green, and blue color filter formed while overlapping the black matrix with a predetermined portion; An overcoat layer formed on the black matrix and the color filter; The overcoat layer formed on the stepped portion formed by overlapping the black matrix and the color filter may have a shape removed by a predetermined thickness through diffraction exposure during mask exposure.

Here, the predetermined area is an area between the non-display area through which the backlight is not transmitted and the red, green, and blue color filters formed on the display area through which the backlight is transmitted, as the outer portion of the substrate. The overcoat layer formed on the mask is removed through a mask process, and the alignment layer is further provided on the overcoat layer.

In addition, the method for manufacturing a color filter substrate of a liquid crystal display according to the present invention comprises the steps of preparing a substrate; Forming a black matrix in a predetermined area defined on the substrate; Forming a color filter of red, green, and blue to partially overlap the black matrix; Forming an overcoat layer on the black matrix and the color filter; Compensating the stepped portion by removing the overcoat layer formed on the stepped portion formed by overlapping the black matrix and the color filter by a predetermined thickness during diffraction exposure during mask exposure.

Here, the mask used during the exposure of the mask is defined as a semi-transmissive region composed of a transmission region that transmits light, a shielding region that blocks light, and a diffraction pattern that transmits only a predetermined amount of light. The region may be positioned to correspond to the overcoat layer formed on the stepped portion formed by overlapping the black matrix and the color filter.

In addition, the predetermined area is an area between the non-display area through which the back light is not transmitted and the red, green, and blue color filters formed on the display area through which the back light is transmitted as an outer portion of the substrate, and the non-display area. The overcoat layer formed on the mask is removed through a mask process, and the alignment layer is formed on the overcoat layer.

According to the present invention, the thickness difference remaining after the leveling between the color filter and the black matrix due to the overcoat layer formation when the IPS mode liquid crystal display device color filter substrate is formed is compensated additionally, thereby improving the flatness of the overcoat layer. Thereafter, damage to the alignment layer may be minimized during the rubbing process of the alignment layer.

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

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

However, this is a process sectional view of the same part as the cross section of the conventional color filter substrate shown in Figs. 2A to 2F.

A process of manufacturing a color filter substrate of an IPS mode liquid crystal display according to the present invention will be described with reference to FIGS. 4A to 4F as follows.

First, as shown in FIG. 4A, a black matrix 52 is formed in a predetermined region on the substrate 50.

Here, the predetermined area is an area between the non-display area E through which the back light is not transmitted and the red, green and blue color filters formed on the display area D through which the back light is transmitted as an outer portion of the substrate. Say

That is, the black matrix 52 is generally positioned between the red, green, and blue patterns, which are sub color filters in the display area D, and has a reverse tilt domain formed around the pixel area formed on the lower substrate. To shield the light that passes through It is also formed on the outer portion of the liquid crystal panel, that is, on the non-display area E of the panel through which light is not transmitted.

As the material of the black matrix 52, a metal thin film such as chromium (Cr) having an optical density of 3.5 or more or an organic material of carbon system is mainly used, and chromium (Cr) / chromium oxide (CrO _X The black matrix of the bilayer structure such as) is also used for the purpose of low reflection. Therefore, according to the purpose, any of the above-mentioned materials is used to form the black matrix 52.

Next, as shown in FIG. 4B, a color filter 54 using color resin having red / green / blue color is formed.

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.

In addition, the color filter 54 is formed between the etched regions of the black matrix 52 formed on the display area D. The color filter 54 may be formed by a printing method, a dyeing method, or a polymer. Electrodeposition method, pigment dispersion method and the like.

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.

In this case, 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, and post-bake processes may be used. Can be patterned via

That is, a red, green, and blue color resin having red color is applied to the entire surface of the substrate 50 on which the black matrix 52 is formed, and then selectively exposed to a desired area. A red sub color filter is formed on the substrate. (The order of coloring is decided by the order of red (R), green (G), blue (B).)

Next, a green color resin is coated on the entire surface of the substrate 50 on which the red color filter is formed, and then selectively exposed to form a green color filter.

Subsequently, a blue color resin is coated on the entire surface of the substrate 50 on which the red and green color filters are formed, and then selectively exposed to form a blue color filter.

As described above, the red, green, and blue color filters 54 are formed between the black matrices 52 formed in the display area D. In this case, the adjacent color filters 54 and the black matrix 52 have a predetermined portion. There is a region overlapping with respect to, and thus, the stepped portion F is generated as shown by the regions overlapping each other.

Next, as shown in FIG. 4C, an overcoat layer is formed to planarize the surface of the substrate on which the color filter is formed.

In order to planarize the substrate 50 on which the color filter and the black matrix are formed, the overcoat layer 56 is coated with a transparent resin having an insulating property on the substrate 50. (Acryl) or polyimide-based resin (Resin) is used.

In the conventional case, in the overcoat layer coated on the display area, a slight step is left in the area where the step part is formed by the step part generated by the color filter and the black matrix overlapping each other.

As a result, the overcoat layer also has a bend in the stepped area, thereby rubbing the alignment layer formed on the overcoat layer. damage) caused large and small alignment film residues.

The present invention not only applies the transparent resin as the overcoat layer on the substrate on which the color filter and the black matrix are formed, but also on the stepped portion F generated by overlapping the black matrix and the color filter. As shown in FIG. 4D, the overcoat layer 56 formed thereon is removed by a predetermined thickness through diffraction exposure using a semi-transmissive region 64 having a diffraction pattern when the mask 60 is exposed to compensate for the stepped portion. .

Here, the mask 60 used in the mask exposure includes a semi-transmissive region including a transmissive region 62 for transmitting light, a shielding region 66 for blocking light, and a diffraction pattern for transmitting only a predetermined amount of light. The semi-transmissive region 64 of the mask 60 is defined as 64, and the overcoat layer 56 formed on the stepped portion F generated by the black matrix 52 and the color filter 54 are overlapped. It is characterized in that the corresponding position.

In addition, when the overcoat layer has a negative photoresist property, the shielding area 66 of the mask 60 is positioned to correspond to the non-display area E of the substrate. This is because the negative photoresist has a property of removing an unexposed portion.

As a result, after the transparent resin as the overcoat layer 56 is applied onto the substrate on which the color filter and the black matrix are formed, and then subjected to a photo process such as mask exposure using a mask having a pattern as described above, the non-display The overcoat layer formed on the region E is removed.

In addition, the overcoat layer formed on the stepped portion F is removed by a predetermined thickness by diffraction exposure to compensate for the stepped portion, whereby the bending in the stepped region of the overcoat layer 56 is provided. It can be removed.

Here, the overcoat layer formed on the non-display area E may be removed to maintain the cell gap between the two substrates because the region includes a region to which the sealant is attached when the array substrate and the color filter substrate are bonded together. Because of the reason.

As shown in FIG. 4E, the overcoat layer formed on the non-display area E is removed and the overcoat layer formed on the stepped portion F is removed by a predetermined thickness by diffraction exposure. .

Next, as shown in FIG. 4F, an alignment layer 58 is formed on the overcoat layer 56, and rubbing is performed on the alignment layer 58.

Through the process as described above, the color filter substrate according to the present invention can be configured, and thus, the overcoat layer is removed by removing a slight bending caused by the stepped portion formed in the region where the color filter and the black matrix overlap. It is possible to minimize the damage of the alignment layer during the rubbing process of the alignment layer by improving the flatness of the.

It will be apparent to those skilled in the art that the present invention described above can be applied to a liquid crystal display device such as a TN mode in addition to the IPS mode liquid crystal display device.

As described above, according to the color filter substrate and the manufacturing method of the liquid crystal display according to the present invention, the color filter substrate of the conventional IPS mode liquid crystal display is formed even after the leveling step between the color filter and the black matrix by the overcoat layer formation. By additionally compensating for the thickness difference, the flatness of the overcoat layer may be improved, thereby minimizing damage to the alignment layer during the rubbing process of the alignment layer.

1 is a cross-sectional view of a specific portion of a conventional liquid crystal display in IPS mode.

2A to 2F are cross-sectional views illustrating a process for manufacturing a color filter substrate of a conventional IPS mode liquid crystal display device.

3A and 3B illustrate problems of a conventional color filter substrate structure.

4A to 4F are cross-sectional views showing the manufacturing process of the liquid crystal display device of the color filter substrate according to the present invention;

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

50: substrate 52: black matrix

54 color filter 56 overcoat layer

58: alignment layer 60: mask

62: transmission region 64: semi transmission region

66: shielding area

Claims (10)

Substrate, A black matrix formed in a predetermined region defined on the substrate; Red, green, and blue color filters formed by overlapping the black matrix with a predetermined portion, An overcoat layer formed on the black matrix and the color filter; And an overcoat layer formed on the stepped portion formed by overlapping the black matrix and the color filter to have a shape removed by a predetermined thickness through diffraction exposure during mask exposure. The method of claim 1, The predetermined area is an outer portion of the substrate, wherein the liquid crystal display device is an area between a non-display area through which the backlight is not transmitted and the red, green, and blue color filters formed on the display area through which the backlight is transmitted. Color filter substrate. The method of claim 2, The overcoat layer formed on the non-display area is removed by a mask process, the color filter substrate of the liquid crystal display device. The method of claim 1, The color filter substrate of the liquid crystal display device, characterized in that the alignment layer is further provided on the overcoat layer. Preparing a substrate; Forming a black matrix in a predetermined area defined on the substrate; Forming a color filter of red, green, and blue so as to overlap a portion of the black matrix; Forming an overcoat layer on the black matrix and the color filter; Compensating the stepped portion by removing the overcoat layer formed on the stepped portion formed by overlapping the black matrix and the color filter by a predetermined thickness during diffraction exposure during mask exposure. Color filter substrate manufacturing method. The method of claim 5, The mask used in the exposure of the mask is defined as a semi-transmissive region comprising a transmission region for transmitting light, a shielding region for blocking light, and a diffraction pattern for transmitting only a predetermined amount of light. Color filter substrate manufacturing method. The method of claim 6, And a semi-transmissive region of the mask corresponds to an overcoat layer formed on a stepped portion formed by overlapping the black matrix and the color filter. The method of claim 5, The predetermined area is an outer portion of the substrate, wherein the liquid crystal display device is an area between a non-display area through which the backlight is not transmitted and the red, green, and blue color filters formed on the display area through which the backlight is transmitted. Color filter substrate manufacturing method. The method of claim 8, The overcoat layer formed on the non-display area is removed by a mask process. The method of claim 5, The method of manufacturing a color filter substrate of a liquid crystal display device, further comprising the step of forming an alignment layer on the overcoat layer.