KR20050117031A - Method for manufacturing color filter substrate - Google Patents

Abstract

The present invention relates to a method for manufacturing a color filter substrate having improved contrast ratio by removing a material protruding from an overlapping portion between a color filter layer and a black matrix layer, and improving the contrast ratio. Forming a color filter layer, filling a space between the color filter layers, forming a black matrix layer, removing a predetermined thickness of the overlapped black matrix layer on the color filter layer, and the color filter layer and the black matrix layer It characterized in that it comprises a step of forming an overcoat layer on the front surface of the substrate.

Description

Method for manufacturing color filter substrate {Method for Manufacturing Color Filter Substrate}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a method of manufacturing a color filter substrate in which a flatness is improved by removing a material protruding from an overlapping portion between a color filter layer and a black matrix layer, thereby improving contrast ratio. It is about.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELD), and vacuum fluorescent (VFD) Various flat panel display devices such as displays have been studied, and some of them are already used as display devices in various devices.

Among them, LCD is the most widely used as the substitute for CRT (Cathode Ray Tube) for mobile image display device because of its excellent image quality, light weight, thinness, and low power consumption. In addition to the use of the present invention has been developed in various ways such as a television and a computer monitor for receiving and displaying broadcast signals.

In order to use such a liquid crystal display as a general screen display device in various parts, it is a matter of how high quality images such as high definition, high brightness and large area can be realized while maintaining the characteristics of light weight, thinness and low power consumption. Can be.

A general liquid crystal display device may be broadly divided into a liquid crystal panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel, wherein the liquid crystal panel includes first and second glass substrates bonded to each other with a predetermined space; It consists of a liquid crystal layer injected between said first and second glass substrates.

The first glass substrate (TFT array substrate) may include a plurality of gate wires arranged in one direction at a predetermined interval, a plurality of data wires arranged at regular intervals in a direction perpendicular to the respective gate wires, A plurality of pixel electrodes formed in a matrix form in each pixel region defined by crossing gate lines and data lines, and a plurality of thin film transistors switched by signals of the gate lines to transfer signals of the data lines to each pixel electrode. Is formed.

The second glass substrate (color filter substrate) includes a light shielding layer for blocking light in portions other than the pixel region, an R, G, and B color filter layers for expressing color colors, and a common electrode for implementing an image. Is formed.

The driving principle of the general liquid crystal display device uses the optical anisotropy and polarization property 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 arrangement of molecules can be controlled by artificially applying an electric field to the liquid crystal.

Therefore, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction of the liquid crystal by optical anisotropy, thereby representing image information.

Hereinafter, a conventional liquid crystal display and a method of manufacturing the same will be described with reference to the accompanying drawings.

1 is an exploded perspective view illustrating a general liquid crystal display device.

As shown in FIG. 1, a general liquid crystal display device is injected between a first substrate 1 and a second substrate 2 bonded to each other with a predetermined space, and between the first substrate 1 and the second substrate 2. It consists of the liquid crystal layer 3.

In more detail, the first substrate 1 may have a plurality of gate lines 4 in one direction and constant in a direction perpendicular to the gate lines 4 at regular intervals to define the pixel region P. FIG. A plurality of data lines 5 are arranged at intervals. In addition, a pixel electrode 6 is formed in each pixel region P, and a thin film transistor T is formed at a portion where each of the gate lines 4 and the data lines 5 intersect with each other so that the thin film transistors are formed. The data signal of the data line is applied to each pixel electrode according to the signal of the gate line.

In addition, a black matrix layer 7 is formed on the second substrate 2 to block light in portions other than the pixel region P, and portions R corresponding to the respective pixel regions are formed to express colors. , G, B color filter layers 8 are formed, and a common electrode 9 for realizing an image is formed on the color filter layers 8.

In the liquid crystal display as described above, the liquid crystal layer 3 formed between the first and second substrates 1 and 2 is oriented by an electric field formed between the pixel electrode 6 and the common electrode 9, The amount of light passing through the liquid crystal layer 3 may be adjusted according to the degree of alignment of the liquid crystal layer 3 to express an image.

Such a liquid crystal display is called a twisted nematic (TN) mode liquid crystal display, and the TN mode liquid crystal display has a disadvantage of having a narrow viewing angle, and an in-plane switching (IPS) mode liquid crystal display for overcoming such disadvantages. Was developed.

In the IPS mode liquid crystal display, a pixel electrode and a common electrode are formed parallel to each other at a predetermined distance in a pixel area of a first substrate, and a horizontal electric field is generated between the pixel electrode and the common electrode so that the horizontal The liquid crystal layer is aligned by the electric field.

The liquid crystal display of the IPS mode has an initial orientation of an alignment layer (not shown) formed on the first and second substrates 1 and 2 to facilitate horizontal alignment when the voltages are opposed to each other. Rub to have an angle.

Hereinafter, the manufacturing method of the color filter substrate of the liquid crystal display device of an IPS mode is demonstrated.

Meanwhile, the black matrix layer constituting the conventional liquid crystal display device may use chromium (Cr) or resin (Resin) as its material.

FIG. 2 is a cross-sectional view illustrating a color filter substrate including a black matrix layer formed of chromium components along the line II ′ of FIG. 1.

As shown in FIG. 2, when the black matrix layer 7a is formed of chromium (Cr), patterning is possible with a thin thickness of 0.1 to 0.3 μm due to the characteristics of the metal component of chromium.

Therefore, the black matrix layer 7a of the chromium (Cr) component is formed on a predetermined portion on the second substrate 2, and the color filter layer 8 is formed on the second substrate 2 including the black matrix layer 7a. After the formation, since the thickness of about 0.1 to 0.3 µm is protruded from other portions in the overlap region between the color filter layer 8 and the black matrix layer 7a, the overcoat layer 11 having a thickness of 1 to 2 µm is formed. After being formed on the entire surface of the second substrate 2 including the black matrix layer 7a and the color filter layer 8, the top surface of the overcoat layer 11 becomes substantially flat.

After the alignment layer 15 is formed on the upper surface of the overcoat layer 11, when the rubbing treatment is performed on the alignment layer 15, the surface of the alignment layer 15 forms a flat surface without a protruding portion, so rubbing is easy, and Since the alignment film 15 itself does not have irregularities, the alignment of the liquid crystal adjacent to the alignment film 15 is made without distortion.

However, despite the great advantage that the patterning is easy when forming the black matrix layer using chromium, the chromium generates harmful chemical components when patterning with heavy metals, and therefore, appropriate wastewater treatment is required for patterning. Do. Waste water treatment requires equipment, and if this waste water treatment is not done properly, it causes environmental pollution. As a result, the problem of increased costs for wastewater treatment is greater than the ease of patterning, and thus a new material having low environmental pollution with a black matrix has been required.

FIG. 3 is a cross-sectional view illustrating a color filter substrate on which a black matrix layer and a color filter layer formed of a resin component are formed, along a line II ′ of FIG. 1, and FIG. 4 is an overcoat on the black matrix layer and the color filter layer of FIG. 3. It is a structure sectional drawing which shows the color filter substrate which formed the layer.

As shown in FIG. 3, when the black matrix layer 17 is formed of a resin component, the resin component cannot be patterned in a fine size and can be patterned in micrometers (μm), so that patterning is performed in a minimum unit. Even if it is made, the width of about 10 micrometers and the thickness are about 1-2 micrometers thickness in order to maintain black-matrix characteristic.

Therefore, the black matrix layer 17 of the resin component is formed on a predetermined portion on the second substrate 2, and the color filter layer 18 is formed on the second substrate 2 including the black matrix layer 17. Afterwards, a thickness of about 0.8 [mu] m or more is protruded from other portions in the overlap region between the color filter layer 18 and the black matrix layer 17. FIG.

In order to planarize the surface of the color filter layer 18 having irregularities as described above, as shown in FIG. 4, the second coat including the black matrix layer 17 and the color filter layer 18 includes an overcoat layer 19 having a thickness of 1 to 2 μm. It is formed in the front of the board | substrate 2. However, in the overlap region between the black matrix layer 17 and the color filter layer 18, since the protrusion thickness is 0.8 μm or more than other portions, the protrusions are formed even after the overcoat layer 19 having a thickness of about 1 to 2 μm is formed. The overcoat layer 19 at the site is less likely to be patterned lower than within 0.4 μm as compared to other sites. Therefore, the surface of the overcoat layer 19 has irregularities, and the irregularities are provided up to the alignment film 15 formed thereon.

As a result, the rubbing treatment is not easily performed on the alignment layer 15, and the alignment of the liquid crystal near the alignment layer 15 may not be performed smoothly due to the unevenness of the alignment layer 15, resulting in alignment distortion. Can be.

The color filter substrate of the conventional liquid crystal display device as described above has the following problems.

In the conventional color liquid crystal display device, a black matrix is formed corresponding to the light leakage region in order to cover the light leakage region on the TFT array substrate side.

As a material of such a black matrix, chromium (Cr), which is a light-shielding heavy metal, has been used in the past, but in recent years, it has been replaced with a black matrix of a resin component in terms of environmental pollution due to harmful cost generated in manufacturing cost and patterning process. have.

By the way, when using the black matrix layer of a resin component, it has a film thickness about 10 times compared with the black matrix of a chromium component by the characteristic of a material. For example, if chromium can be deposited to a thickness of 0.1 μm, the resin can be deposited to a thickness of 1 μm.

Therefore, in the case of forming the R, G, B color filter layers on the resin black matrix layer, a projected portion of about 0.8 mu m occurs in the portion of the color filter layer in the portion overlapping with the black matrix layer. On the top of the R, G, and B color filters, an average of about 0.8 μm is periodically repeated. In this case, the overlapped portion is approximately rounded protrusion shape.

An overcoat layer is formed on the R, G, and B color filters to smooth the height difference between a portion having a protrusion and a portion having no protrusion, but the color filter and the black matrix are deposited even when the overcoat layer is deposited. Steps with other portions of the protrusions remaining at the overlapped portions of the layer affect the alignment process that is performed later, and become a factor that affects light scattering.

Therefore, distortion of the liquid crystal alignment occurs even in the off state, thereby affecting the luminance of the black state.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the flatness is improved by removing the material protruding from the overlapped portion between the color filter layer and the black matrix layer, thereby improving the contrast ratio. It is an object to provide a manufacturing method.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, the method including forming a color filter layer at a predetermined portion on a substrate, filling a space between the color filter layers, and forming a black matrix layer; It is characterized in that it comprises the step of removing a predetermined thickness of the overlapped black matrix layer on the color filter layer and forming an overcoat layer on the entire surface of the substrate including the color filter layer and the black matrix layer.

The black matrix layer overlapped on the color filter layer is removed to a thickness of 0.01 ~ 1.50㎛.

Removing the black matrix layer overlapping the color filter layer to a predetermined thickness is performed using a polishing equipment.

The method may further include forming an alignment layer on the entire overcoat layer.

The method may further include forming a column spacer on the overcoat layer corresponding to the black matrix layer. In this case, the method may further include forming an alignment layer on the entire overcoat layer including the column spacer.

The method may further include depositing a transparent conductive film on the back surface of the substrate.

Hereinafter, a method of manufacturing a color filter substrate of the present invention and a liquid crystal display device manufactured by the same will be described in detail with reference to the accompanying drawings.

FIG. 5 is a plan view showing a liquid crystal display device manufactured by the method for manufacturing a color filter substrate of the present invention, and FIG.

5 and 6, the liquid crystal display device of the present invention described in the following embodiments is a liquid crystal display device in IPS mode (In-Plane Switching mode), a TFT array substrate (not shown) and the TFT array It includes a color filter array substrate formed to face the substrate and a liquid crystal layer (not shown) filled between the two array substrate.

The TFT array substrate may include a thin film transistor (TFT) formed at an intersection of the gate line 111 and the data line 112 and the gate line 111 and the data line 112 that cross each other to define a pixel region. ), A pixel electrode 113 and a common electrode 117a alternately formed in a zigzag pattern in the pixel region, and are formed to cross the pixel region in parallel with the gate line 111. A common line 117 connected to the 117a and a storage electrode 113a overlapping the common line 117 with a predetermined portion within the pixel area and branching the pixel electrode 113 are included.

The thin film transistor TFT may include a gate electrode 111a protruding from the gate line 111 and a source electrode 112a and a drain electrode 112b spaced apart from each other by a predetermined interval to cover both sides of the upper portion of the gate electrode 111a. ), A channel is formed at a portion of the source electrode 112a and the drain electrode 112b spaced apart from each other, and is formed under the metal layer forming the data line 112, the source electrode 112a, the drain electrode 112b, and the like. It includes a formed semiconductor layer (not shown).

A gate insulating film (not shown) covering the gate line 111 and the gate electrode 111a is formed on the entire surface of the substrate under the semiconductor layer, and a passivation layer is disposed between the drain electrode 112b and the pixel electrode 113. (Not shown) is provided with a protective film hole in the protective film to contact the drain electrode 112b and the pixel electrode 113.

Here, the common line 117 and the common electrode 117a branched from the common line 117 are simultaneously deposited in the gate line 111 forming step, and the pixel electrode 113 is formed on the passivation layer including the passivation layer hole. Is formed.

Further, an alignment film whose surface is rubbed at an angle of 0 to 5 ° is further formed on the top surface of the TFT array substrate.

In the color filter array substrate corresponding to the TFT array substrate, the substrate 100 has the following configuration.

Filling the spaces between the R, G, and B color filter layers 101 and R, G, and B color filter layers 101 formed on the substrate 100 corresponding to the pixel regions of the TFT array substrate; The black matrix layer 102 of the resin component formed by removing a thickness of 0 to 1.50 μm from the upper portion overlapping both sides of each of the G, B color filter layers 101 and flattening the surface thereof, and the R, G, and B colors The front surface of the substrate including the color filter layer 101 and the black matrix layer 102 is covered, and an upper surface thereof corresponds to the flattened overcoat layer 103 and the upper portion of the black matrix layer 102. And a column spacer 104 formed on the overcoat layer 103 and an alignment layer 105 formed on the entire surface of the overcoat layer 103 including the column spacer 104.

Here, the column spacer 104 is formed by applying a positive photosensitive resin, a negative photosensitive resin, an organic insulating film, or the like on the overcoat layer 103 and then patterning the same.

Although not shown, a transparent conductive film (ITO film) is formed on the rear surface of the substrate 100 to prevent static electricity during driving.

7A to 7F are process cross-sectional views of a method of manufacturing a color filter substrate of the present invention.

As shown in FIG. 7A, first, color filter layers 101 of R, G, and B are formed for each pixel on the substrate 100. At this time, the process order of each color filter layer is irrelevant, and when forming the color filter layer 101 of each of the R, G, B, the height of each color filter layer 101 is all the same level.

As shown in FIG. 7B, a black matrix material made of a light blocking resin is formed on the entire surface of the substrate 100 by filling the space between the color filter layers 101 of R, G, and B, and then selectively removing the TFT matrix. The black matrix layer pattern 102a is left in a portion corresponding to the non-pixel region (gate line and data line corresponding region, thin film transistor formation region) of the substrate.

As shown in FIG. 7C, an upper portion of each of the color filter layers 101 of the R, G, and B layers corresponds to a height of the embedded black matrix layer pattern 102a between the color filter layers 101 of the R, G, and B layers. The black matrix layer 102 is planarized by polishing the black matrix layer material overlapping with the black matrix layer material.

At this time, the polishing is performed using a polishing equipment, in this case, the black matrix layer pattern 102c positioned on both sides of the color filter layer 101 has a predetermined thickness, that is, the area between the color filter layers 101. Since the protrusion protrudes from about 0.8 μm to 1.00 μm, selective polishing of the protrusion is possible.

The thickness of the black matrix layer pattern to be polished during polishing is 1.00 μm, and after polishing, the black matrix layer 102 is planarized to have a thickness of the black matrix layer pattern formed in the region between the color filter layers 101. At this time, the black matrix layer 102 is in a state where only a thickness within about 0.3 μm of the color filter layer 101 protrudes from a portion overlapping with the color filter layer 101.

As shown in FIG. 7D, an overcoat layer 103 is formed on the substrate 100 including the black matrix layer 102 and the color filter layer 101. In this case, the overcoat layer 103 is formed to a thickness of about 1.5 to 2.5㎛, which is a relatively five times or more than the thickness of the color filter layer 101 and the black matrix layer 102 overlapping After the overcoat layer 103 is formed, planarization between the overlapped portion of the color filter layer 101 and the black matrix layer 102 and the remaining region can be maintained.

As shown in FIG. 7E, the positive photosensitive resin, the negative photosensitive resin, or the organic insulating film is formed to a thickness of about 2 to 5 μm, and then selectively removed to form the column spacer 104. In this case, the column spacer 104 may prevent light leakage to be formed on the overcoat layer 103 corresponding to the portion where the black matrix layer 102 is formed.

As shown in FIG. 7F, the alignment layer 105 is formed on the entire surface of the overcoat layer 103 including the column spacer 104, and then the upper surface thereof is rubbed.

When the color filter substrate is formed by such a manufacturing method, since the alignment layer 105 secures flatness on the remaining surface except for the region where the column spacer 104 is formed, the rubbing treatment can be performed smoothly.

Therefore, the liquid crystal may be aligned to correspond to the surface having flatness except for the column spacer 104 region corresponding to the light leakage region, so that the liquid crystal is aligned without distortion.

In addition, in the liquid crystal display device in which the off state is driven to black, as in the above-described liquid crystal display device in the IPS mode, the liquid crystal alignment is made without distortion, and light leakage defects do not occur, so that the contrast ratio between the black state and the white state ( contrast ratio is improved.

Meanwhile, in the above-described embodiment, the method of manufacturing the color filter substrate of the liquid crystal display of the IPS mode has been described, but the same process method may be applied to the method of manufacturing the color filter substrate of the liquid crystal display of the TN mode. .

In the case of the liquid crystal display of the TN mode, except that the pixel electrode is formed on the TFT array substrate side and the common electrode is formed on the front surface of the color filter substrate, and a vertical electric field is formed between the pixel electrode and the common electrode to drive. Follows a structure similar to the IPS mode.

The manufacturing method of the color filter substrate of the present invention as described above has the following effects.

First, after the color filter layer is formed, a black matrix layer of a resin component is formed in the space between the color filter layers, and then the black matrix layer is removed by removing a predetermined thickness in the overlap region between the color filter layer and the black matrix layer. By securing the flatness of the layer in advance, it is possible to form the thickness of the overcoat layer relatively thinner than the conventional one.

Second, due to the removal of the thickness of the black matrix layer at the overlapped portion of the color filter layer and the black matrix layer, even after the conventional overcoat layer is formed, almost perfect flatness can be obtained in the overlapped region compared with the uneven point. .

Third, the alignment film formed on such a flattened overcoat layer also has a flattening characteristic, and thus rubbing treatment is performed smoothly.

Fourth, the liquid crystal alignment near this flattened alignment film is made without distortion, thereby improving the path deviation of light due to the dispersion of the alignment of the liquid crystal. In particular, in the IPS mode liquid crystal display device, the amount of black light in the off state can be significantly reduced, so that the contrast ratio can be improved.

1 is an exploded perspective view showing a general liquid crystal display device

FIG. 2 is a cross-sectional view illustrating a color filter substrate including a black matrix layer formed of chromium components along the line II ′ of FIG. 1.

FIG. 3 is a cross-sectional view illustrating a color filter substrate on which a black matrix layer and a color filter layer formed of a resin component are formed along the line II ′ of FIG. 1.

4 is a cross-sectional view illustrating a color filter substrate in which an overcoat layer is formed on the black matrix layer and the color filter layer of FIG. 3.

5 is a plan view showing a liquid crystal display device manufactured by a method of manufacturing a color filter substrate of the present invention.

6 is a structural cross-sectional view taken along line II-II 'of FIG. 5.

7A to 7F are cross-sectional views illustrating a method of manufacturing the color filter substrate of the present invention.

* Description of symbols on the main parts of the drawings *

100: color filter substrate 101: color filter layer

102: black matrix layer 103: overcoat layer

104: column spacer 105: alignment layer

Claims (7)

Forming a color filter layer on a predetermined portion on the substrate; Filling a space between the color filter layers to form a black matrix layer; Removing a predetermined thickness of the overlapped black matrix layer on the color filter layer; And And forming an overcoat layer on the entire surface of the substrate including the color filter layer and the black matrix layer. The method of claim 1, The black matrix layer overlapped on the color filter layer is removed to a thickness of 0.01 ~ 1.50㎛. The method of claim 1, And removing the black matrix layer overlapping the color filter layer to a predetermined thickness by using a polishing equipment. The method of claim 1, The method of manufacturing a color filter substrate further comprising the step of forming an alignment film on the entire overcoat layer. The method of claim 1, Forming a column spacer on the overcoat layer corresponding to the black matrix layer, characterized in that it further comprises a color filter substrate. The method of claim 5, And forming an alignment layer on the entire overcoat layer including the column spacer. The method of claim 1, And depositing a transparent conductive film on the back surface of the substrate.