KR100996505B1 - Method of fabricating the color filter substrate for Liquid crystal display device - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a color filter substrate for a liquid crystal display device which can reduce a process and reduce material costs in further forming a white color filter layer.

The present invention includes forming a black matrix having first, second, third, and fourth openings corresponding to red, green, blue, and white sub-pixels, respectively; Forming each of the red, green, and blue color filter layers in the first, second, and third openings; A method of manufacturing a color filter substrate for a liquid crystal display device comprising applying an overcoat resin on each of the red, green, and blue color filter layers and the fourth opening to form an overcoat layer having a flat surface including a white sub-pixel. To provide.

According to the present invention, by forming a white color filter layer as an overcoat layer without forming a separate white color filter layer, the number of mask processes for forming a white color filter layer can be reduced, and thus the material cost can be reduced. have.

Description

Method of fabricating the color filter substrate for Liquid crystal display device             

1 is a view schematically showing a general liquid crystal display device.

2 is a cross-sectional view showing a color filter substrate for a liquid crystal display device having red, green, and blue sub pixels.

3 is a cross-sectional view of a conventional liquid crystal display substrate having red, green, blue, and white sub-pixels.

4A to 4G are cross-sectional views of a manufacturing process showing a method of manufacturing a conventional color filter substrate for a liquid crystal display.

5 is a cross-sectional view showing a color filter substrate for a liquid crystal display device according to a first embodiment of the present invention;

6A to 6G are cross-sectional views of a manufacturing process showing a method of manufacturing a color filter substrate for a liquid crystal display device according to a first embodiment of the present invention.

7 is a partial cross-sectional view of a slit coating apparatus for a doctor blade used to form a color filter substrate for a liquid crystal display device according to a second embodiment of the present invention.

8A to 8G are cross-sectional views of a manufacturing process showing a method of manufacturing a color filter substrate for a liquid crystal display device according to a second embodiment of the present invention.

<Brief description of the main parts of the drawing>

410: substrate 420: black matrix

425: opening 430: color filter layer

440: overcoat layer 470: slit bar

475: Doctor Blade

The present invention relates to a liquid crystal display device and a manufacturing method thereof.

In general, a liquid crystal display device displays an image by using optical anisotropy and birefringence characteristics of liquid crystal molecules. When an electric field is applied, the alignment of liquid crystals is changed, and the characteristics of light transmission vary according to the arrangement direction of the changed liquid crystals. In general, a liquid crystal display device is formed by arranging two substrates on which electric field generating electrodes are formed so that the surfaces on which the two electrodes are formed face each other, injecting a liquid crystal material between the two substrates, and then applying a voltage to the two electrodes. By moving the liquid crystal molecules by the electric field is a device that represents the image by the transmittance of light that varies accordingly.

1 is a view schematically showing a general liquid crystal display device.                         

As shown in the drawing, a general color liquid crystal display device 11 includes a black matrix 6 formed between a color filter layer 8 and a color filter layer 8 of red, green, and blue colors. And an upper substrate 5 on which the common electrode 18 deposited on the color filter 8 is formed, a pixel region P is defined, and a pixel electrode 17 and a switching element T in the pixel region P. And a lower substrate 22 having array wiring formed around the pixel region P. The liquid crystal 14 is filled between the upper substrate 5 and the lower substrate 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 passing through the plurality of thin film transistors T is crossed. And data wirings 15 are formed. In this case, the pixel region P is a region defined by the intersection of the gate wiring 13 and the data wiring 15. A transparent pixel electrode 17 is formed on the pixel region P as described above.

The pixel electrode 17 uses a transparent conductive metal having relatively high light transmittance, such as indium-tin-oxide (ITO). A storage capacitor C _ST connected in parallel with the pixel electrode 17 is formed on the gate wiring 13, and a portion of the gate wiring 13 is used as the first electrode of the storage capacitor C _ST . As the second electrode, an island-shaped source / drain metal layer 30 formed of the same material as the source and drain electrodes is used.

Here, the source / drain metal layer 30 is configured to be in contact with the pixel electrode 17 to receive a signal of the pixel electrode.

In the liquid crystal display device as described above, red, green, and blue sub-pixels for displaying red, green, and blue, respectively, form one pixel to display colors.

2 is a cross-sectional view of a color filter substrate for a liquid crystal display device having red, green, and blue sub-pixels.

As shown, a conventional color filter substrate for a liquid crystal display device has a first, second, and third openings 125a, 125b, and 125c corresponding to red, green, and blue subpixels on the substrate 110, respectively. The overcoat layer 140 is formed on the matrix 120, the openings 125, and the red, green, and blue color filter layers 130a, 130b, and 130c, and the color filter layer 130, respectively.

The red, green, and blue color filter layers 130a, 130b, and 130c display red, green, and blue colors, respectively, and the overcoat layer 140 formed on the color filter layer 130 flattens the substrate for the liquid crystal display device.

On the other hand, a quad type liquid crystal display device capable of increasing luminance by additionally configuring white subpixels displaying white in red, green, and blue subpixels is used.

3 is a cross-sectional view showing a conventional color filter substrate for a liquid crystal display device having red, green, blue, and white sub-pixels.

As shown in the drawing, a white sub pixel is additionally formed on a conventional color filter substrate for a liquid crystal display, and a white color filter layer 230d for driving the white sub pixel is further formed.

Hereinafter, a method of forming a conventional color filter substrate for a liquid crystal display device will be described with reference to the drawings.

4A through 4G are cross-sectional views illustrating a method of forming a color filter substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

First, as shown in FIG. 4A, first, second, third, and fourth openings 225a, 225b, 225c, and 225d are coated on the substrate 210 and patterned by a mask process. To form a black matrix 220 having. In this case, the light blocking material is preferably selected from black resin or chromium oxide. The first, second, third, and fourth openings 225a, 225b, 225c, and 225d are formed to correspond to the red, green, blue, and white sub-pixels, respectively, and the black matrix 220 includes gate and data lines of the array substrate. It is formed to correspond to the metal pattern in the liquid crystal display such as.

Next, as shown in Fig. 4B, a red photoresist 229 is applied to the entire surface of the substrate. In this case, when the red photoresist 229 receives light with a photosensitive material, the red photoresist 229 removes light when the light is irradiated or the light is not irradiated.

Next, as shown in FIG. 4C, a red photoresist is patterned through a mask process to form a red color filter layer 230a in the first opening 225a.

Next, as shown in FIG. 4D, a green photoresist is applied and patterned through a mask process to form a green color filter layer 230b in the second opening 225b. In this case, the green color filter layer 230b is performed in the same process as the process of forming the red color filter layer 230a.

Next, as shown in FIG. 4F, a blue photoresist is applied to the entire surface of the substrate in the same manner and patterned through a mask process to form a blue color filter layer 230c in the third opening 225c.                         

Next, as shown in FIG. 4E, a white photoresist, more accurately, a photo binder resist in which color pigments have been removed, is applied and patterned through a mask process to form a white color filter layer 230d in the fourth opening 225d. Form. The white color filter layer 230c may also be processed in the same process as forming the red, green, and blue color filter layers 230a, 230b, and 230c.

Next, as shown in FIG. 4G, an overcoat layer 240 is formed on the red, green, blue, and white color filter layers 230. The overcoat layer 240 protects the color filter layer and is formed to planarize the formed color filter layer with a step difference.

Through the above-described process, it is possible to form a conventional liquid crystal display substrate having a white color filter layer. However, as the white color filter layer is further configured, a mask process for forming the white color filter layer is increased, and thus a material cost increases.

An object of the present invention for solving the above problems is to provide a liquid crystal display device and a method of manufacturing the same that can reduce the process and reduce the material cost in the further formation of the white color filter layer.

In order to achieve the above object, the present invention is a manufacturing method of a color filter substrate for a liquid crystal display device in which four sub-pixels of red, green, blue, and white form one pixel, and the red, green, blue, and white Forming a black matrix having first, second, third, and fourth openings corresponding to the sub-pixels, respectively; Forming each of the red, green, and blue color filter layers in the first, second, and third openings; An overcoat resin is applied on the red, green, and blue color filter layers and the fourth openings, and the overcoat resin applied through surface planarization means is flattened to form an overcoat layer having a flat surface including white sub-pixels. It provides a method of manufacturing a color filter substrate for a liquid crystal display device comprising the step.

Forming each of the red, green, and blue color filter layers according to the present invention comprises the steps of: (a) applying each of the red photoresist on a substrate; (b) exposing the applied red photoresist; (c) developing the exposed red photoresist to form a red color filter layer; Replacing the steps (a) to (c) with green and blue photoresist instead of red photoresist, and sequentially forming the green and blue color filter layers, wherein the overcoat layer is a slit coating having a doctor blade. It is characterized by being formed by the device.

In addition, an overcoat resin is applied to each of the red, green, and blue color filter layers and the fourth opening to planarize the overcoat resin applied through a surface planarization means, thereby including an overcoat layer having a flat surface including a white sub-pixel. The forming step includes the steps of: placing a substrate having the red, green, and blue color filter layers on a stage of a slit coating apparatus having a doctor blade as the surface planarization means; Positioning a slit bar and a blade at a predetermined interval on a stage on which the substrate is located; Linearly move the stage at a constant speed, apply an overcoat resin through a slit bar, and push the overcoat resin on the applied substrate with the blade to fill the overcoat resin in a fourth thickness opening with the overcoat layer of a predetermined thickness. Comprising a step of completing the sub-pixel, wherein the thickness of the overcoat layer may be formed to 2㎛ to 12㎛, the overcoat resin is preferably a binder photoresist from which the pigments showing acrylic or color is removed.

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

<First Embodiment>

5 is a cross-sectional view illustrating a substrate for a liquid crystal display device according to a first embodiment of the present invention.

The liquid crystal display according to the first exemplary embodiment of the present invention configures the white color filter layer with the first and second overcoat layers without forming a separate white color filter layer for the white sub-pixels. Therefore, the substrate surface on which the color filter layer is formed can be planarized, and at the same time, the number of manufacturing steps can be reduced.

As shown, the color filter substrate for a liquid crystal display according to the first embodiment of the present invention includes a black matrix 320 having an opening 325 on the substrate 310 and corresponding to each of the openings 325. Red, green, and blue color filter layers 330a, 330b, and 330c and first and second overcoat layers 340 and 350 are formed on the color filter layer 330.

The black matrix 320 is preferably made of black resin or chromium oxide, which is a light blocking material, and although not shown, the black matrix 320 may be formed on metal patterns such as gates, data lines, thin film transistors, etc., which are bonded to correspond to the color filter substrate. It is formed in response. The liquid crystal layer corresponding to the metal pattern formed in the liquid crystal display is not driven as desired to generate light leakage. In order to prevent such light leakage, the black matrix 320 made of a light blocking material corresponds to the metal pattern. Is formed.

First, second, third, and fourth openings 325a, 325b, 325c, and 325d respectively corresponding to the red, green, blue, and white sub-pixels are formed in the black matrix 320.

Each of the red, green, and blue color filter layers 330a, 330b, and 330c is made of a photosensitive material for displaying red, green, and blue, and is formed corresponding to each of the red, green, and blue sub-pixels. The first, second and third openings 325a, 325b and 325c respectively corresponding to the blue sub-pixels are formed.

The first and second overcoat layers 340 and 350 function as a planarization layer for planarizing the substrate for the liquid crystal display device on which the color filter layer 330 is formed. A transparent organic material, for example, an acryl-based material Is made of. The first and second overcoat layers 340 and 350 formed in the fourth opening 325d function as white color filter layers.

The first overcoat layer 340 is formed on the color filter layer 330 and fills the fourth opening 325d. Here, the first overcoat layer 340 filling the fourth opening 325d has a lower height, that is, recessed, relative to the surface of the substrate 310 than the first overcoat layer 340 positioned on the color filter layer 330. In general, the overcoat layer is formed by a spin coating apparatus, and in the partial drawing in which the step is severely formed, a separate white color filter layer is not formed in the fourth opening 325d. Since the step is severely generated, the first overcoat layer 340 is not planarized and has a structure recessed in the four openings. At this time, the step is significantly reduced in the first overcoat layer.

Next, the second overcoat layer 350 is formed on the first overcoat layer 340 to flatten the color filter substrate for the liquid crystal display as a whole. That is, the second overcoat layer 350 uniformly fills the recessed portion of the first overcoat layer 340, that is, the recessed portion of the first overcoat layer 340 corresponding to the fourth opening 325d. The color filter substrate for the liquid crystal display device is planarized.

6A to 6G are cross-sectional views illustrating a method of forming a color filter substrate for a liquid crystal display device according to a first embodiment of the present invention.

First, as shown in FIG. 6A, a light blocking material such as black resin or chromium oxide is coated on the substrate 310 and then patterned by performing a mask process. A black matrix 320 having three and four openings 325a, 325b, 325c, and 325d is formed. The first, second, third, and fourth openings 325a, 325b, 325c, and 325d are formed to correspond to the red, green, blue, and white sub-pixels, respectively, and the black matrix 320 may form a liquid crystal display device. At the time of construction, the metal matrix may be formed to correspond to a metal pattern in a liquid crystal display such as a gate and a data line on an array substrate that are bonded to correspond to a color filter substrate including the black matrix 320.

Next, as shown in FIG. 6B, a red photoresist 329, which is a photosensitive material, is coated on the entire surface of the substrate 310 on which the black matrix 320 is formed.                     

Next, as shown in FIG. 6C, the red color photoresist layer 330a is formed in the first opening 325a by patterning the red photoresist by performing a mask process including an exposure and development process.

Next, as shown in FIG. 6D, a green photoresist is applied and patterned through a mask process to form a green color filter layer 330b in the second opening 325b.

Next, as shown in 6e, a blue photoresist is applied and patterned through a mask process to form a blue color filter layer 330c in the third opening 325c. The blue color filter layer 330c is also performed in the same process as the process of forming the red and green color filter layers 330a and 330b.

Next, as shown to 6f, the 1st overcoat layer 340 is formed. The first overcoat layer 340 is formed on the color filter layer 330 and fills the fourth opening 325d. Since a separate white color filter layer is not formed in the fourth opening portion 325d, the first overcoat layer 340 formed in the fourth opening portion 325d is disposed in the first overcoat layer 340 formed on the color filter layer 330. Compared with the surface of the substrate 310 has a low height.

Next, as shown in FIG. 6G, a second overcoat layer 350 is formed on the first overcoat layer 340. The second overcoat layer 350 uniformly fills the recessed portion of the first planarization 340, that is, the recessed portion of the first overcoat layer 340 corresponding to the fourth opening 325d. The substrate is planarized.

In the first embodiment, two overcoat layers 340 and 350 are formed to evenly form the surface of the overcoat layer. In this case, the second overcoat layer 350 formed over the first overcoat layer 340 is formed. It should be thick enough. Experimentally, 2000 ?? Within this, a flat surface is formed.

However, when the thickness of the overcoat layers 340 and 350 becomes thick, a problem may occur during the rubbing process for liquid crystal alignment during the subsequent process. In addition, since the coating is performed twice, a problem occurs that the manufacturing process time increases.

A method of manufacturing a color filter substrate for a liquid crystal display device that solves the problem of the first embodiment will be described as a second embodiment.

&Lt; Embodiment 2 >

The liquid crystal display according to the second exemplary embodiment of the present invention does not form a separate white color filter layer for a white sub pixel, but uses one overcoat by one coating process using a slit-type coating apparatus having a doctor blade. A method of manufacturing a color filter substrate for a liquid crystal display device capable of simultaneously manufacturing a layer and a white sub pixel is provided, thereby reducing the number of processes.

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

Fig. 7 shows a cross section of the slit, doctor blade and stage of the slit coating apparatus used in the second embodiment of the present invention.

In the slit coating apparatus, a long shaft-shaped slit bar 470 is disposed on the stage 480 on which the substrate 410 can be placed, and is spaced apart from the slit bar 470 by a doctor blade 475. Is located. The slit bar 470 is characterized by applying a certain amount of a liquid material having a viscosity that is supplied to the slit bar 470 by forming a nozzle itself.

The nozzle slit bar 470 is positioned at a predetermined distance from the substrate 410 placed on the stage 480, and a predetermined amount of liquid material is applied through the slit bar 470. The stage 480 is moved at a constant speed so that a certain amount of liquid material is applied to the substrate 410. At this time, the doctor blade 475 which is spaced apart from the slit bar 470 by a predetermined distance is in contact with the surface of the liquid material having a certain viscosity, for example, the photoresist, for example, and pushes the photoresist in one direction. While forming a photoresist layer having a constant thickness, the surface of the photoresist layer is planarized.

8A to 8F are cross-sectional views illustrating a method of forming a color filter substrate for a liquid crystal display device according to a second embodiment of the present invention using the aforementioned slit coating apparatus.

First, as shown in FIG. 8A, a first material on the substrate 410 is formed by applying or depositing a light blocking material such as black resin or chromium oxide on the substrate 410, and patterning the mask by performing a mask process. Black matrix 420 having two, three, four openings 425a, 425b, 425c, and 425d. The first, second, third, and fourth openings 425a, 425b, 425c, and 425d are formed to correspond to the red, green, blue, and white sub-pixels, respectively. In this case, although not shown, the black matrix 420 may be formed to correspond to a metal pattern such as a gate and a data line on the array substrate bonded to the color filter substrate to form the liquid crystal panel.

Next, the same process as described in the first embodiment is performed, and as shown in FIGS. 8B to 8E, red 429, rust (not shown), and the like are formed on the entire surface of the substrate 410 on which the black matrix 420 is formed. A photoresist of blue color (not shown) is applied, and a mask process of exposure and development is performed, and red, green, and blue color filter layers 430a and 430b are formed in the first, second and third openings 424a, 425b and 425c. , 430c) are sequentially formed.

Next, as shown in 8f and 8g, the red, green, and blue color filter layers 430a, 430b, and 430c are formed on the substrate 410 on which the overcoat layer is formed using the slit coating apparatus described with reference to FIG. 7. An overcoat resin, such as a colorless acrylic or a colorless binder resist from which the dye is removed, is coated on the color filter layer 430 to form the overcoat layer 440. In this case, a predetermined amount of overcoat resin is applied onto the substrate 410 through the slit bar 470 of the slit coating apparatus, and the doctor blade 475 located at the rear side of the slit bar 470 receives the coated overcoat resin. The fourth opening 425d is pushed in a direction opposite to the direction of movement of the substrate 410 to smooth its surface, and the red, green, and blue color filter layers 430a, 430b, and 430c between the black matrix 420 are not formed. ) Is filled with the overcoat resin pushed through the doctor blade 475 to form a white color filter layer 430d. The white color filter layer is called a white color filter layer, but is actually transparent and colorless. At this time, it is preferable to appropriately adjust the amount of overcoat resin applied through the slit bar 470 so that the amount of overcoat resin pushed out by the doctor blade 475 can sufficiently fill the four openings 425d. Typically, the thickness of the overcoat layer formed by the spin coating apparatus (not shown) is approximately 1.2 μm to 2 μm, but the overcoat layer according to the second embodiment of the present invention may have a thickness of 2 to reflect the contact error between the blade and the substrate. It is desirable to have a thickness within the range of m to 12 m. At this time, the amount of the overcoat resin applied through the slit bar 470 is that the red, green, and blue color filter layers 430a, 430b, and 430c under the overcoat layer 440 have the same thickness as the overcoat layer 440. Under the assumption, it is desirable to apply an amount capable of forming at least 25% more thickness than the thickness to be formed. For example, the thickness of the color filter layer is approximately 2 μm, and in order to form an overcoat layer having a thickness of 2 μm on the color filter layer, the coating amount should be at least about 2.5 μm.

Next, as described above, the overcoat layer 440 is formed on the color filter layer 430 by the slit coating apparatus including the blade 475, and fills the fourth opening 425d. Accordingly, the white color filter layer and its surface may be formed at the same time as the overcoat layer 440 having a flat and not thick thickness.

When the above process is performed, the color filter substrate for the liquid crystal display device according to the second embodiment of the present invention is formed.

As described above, the color filter substrate for a liquid crystal display according to the second embodiment of the present invention does not form a separate white color filter layer, and has an overcoat having a white sub-pixel and a flat surface by applying one overcoat resin. The layers can be formed simultaneously. Therefore, the mask process for forming the white color filter layer can be eliminated, and thus the material cost can be reduced.

As described above, the present invention, without forming a separate white color filter layer, by forming a white color filter layer with an overcoat layer formed through one application process using a slit coating apparatus provided with a doctor blade, a white color The number of mask processes for forming the filter layer can be eliminated, and thus the material cost can be reduced.

Claims (6)

A manufacturing method of a color filter substrate for a liquid crystal display device in which four sub-pixels of red, green, blue, and white form one pixel, Forming a black matrix having first, second, third, and fourth openings corresponding to the red, green, blue, and white sub-pixels, respectively; Forming each of the red, green, and blue color filter layers in the first, second, and third openings; An overcoat resin is applied on the red, green, and blue color filter layers and the fourth openings, and the overcoat resin applied through surface planarization means is flattened to form an overcoat layer having a flat surface including white sub-pixels. step Method of manufacturing a color filter substrate for a liquid crystal display device comprising a. The method of claim 1, Forming each of the red, green, and blue color filter layers, (a) applying each of the red photoresists onto the substrate; (b) exposing the applied red photoresist; (c) developing the exposed red photoresist to form a red color filter layer; Replacing the steps (a) to (c) with green and blue photoresist instead of red photoresist and repeating sequentially to form green and blue color filter layers Method of manufacturing a color filter substrate for a liquid crystal display device comprising a. The method of claim 1, And the overcoat layer is formed by a slit coating apparatus having a doctor blade. The method of claim 1, Forming an overcoat layer having a flat surface including a white sub-pixel by applying an overcoat resin on each of the red, green, and blue color filter layers and the fourth opening to planarize the overcoat resin applied through surface planarization means. Step is Positioning the substrate with the red, green, and blue color filter layers on a stage of a slit coating apparatus having a doctor blade as the surface planarization means; Positioning a slit bar and a blade at a predetermined interval on a stage on which the substrate is located; Linearly move the stage at a constant speed, apply an overcoat resin through a slit bar, and push the overcoat resin on the applied substrate with the blade to fill the overcoat resin in a fourth thickness opening with the overcoat layer of a predetermined thickness. Step to complete the sub pixel Method of manufacturing a color filter substrate for a liquid crystal display device comprising a. The method according to any one of claims 1 to 4, The thickness of the overcoat layer is a manufacturing method of the color filter substrate for a liquid crystal display device is formed to 2㎛ 12㎛. The method according to any one of claims 1 to 4, The overcoat resin is a manufacturing method of a color filter substrate for a liquid crystal display device, which is a binder photoresist from which an acrylic series or a color pigment is removed.

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