KR20020072348A - a color filter panel for liquid crystal display and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A color filter substrate for a liquid crystal display and a method for fabricating the same are provided to increase the light transmissivity and prevent the decrease of chromaticity by forming transmission grooves and transmission holes in blue color filters, thereby improving the luminance of the LCD. CONSTITUTION: A color filter substrate for a liquid crystal display includes a transparent substrate(210), a black matrix(220) formed on the transparent substrate and having opening parts, color filters(231,241,251) positioned on the opening parts of the black matrix respectively for realizing red, green and blue, an overcoat layer(260) formed on the color filters, and common electrodes(270) formed on the overcoat layer, wherein the color filter for blue has transmission grooves(255) inside.

Description

Color filter substrate for 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 for a liquid crystal display device and a manufacturing method thereof.

Recently, with the rapid development of the information society, there is a need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption, among which a liquid crystal display has a resolution, It is excellent in color display and image quality, and is actively applied to notebooks and desktop monitors.

In general, a liquid crystal display device arranges two substrates on which electrodes are formed so that the surfaces on which the two electrodes are formed face each other, injects a liquid crystal material between the two substrates, and applies a voltage to the two electrodes to generate an electric field. By moving the liquid crystal molecules, the image is expressed by the transmittance of light that varies accordingly.

The lower substrate of the liquid crystal display is formed by repeating a process of forming a thin film and photolithography with an array substrate including a thin film transistor for applying a signal to a pixel electrode. The upper substrate is a substrate including a color filter. Three colors of red (R), green (G) and blue (B) are sequentially arranged, and are produced by methods such as pigment dispersion, dyeing, and electrodeposition.

Hereinafter, a structure of a general liquid crystal display device will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a general liquid crystal display.

As shown in FIG. 1, the lower array substrate has a gate electrode 21 made of a conductive material such as a metal on the transparent first substrate 10, and a silicon nitride film (SiN _x ) or a silicon oxide film ( The gate insulating film 30 made of SiO ₂ covers the gate electrode 21. An active layer 41 made of amorphous silicon is formed on the gate insulating layer 30 on the gate electrode 21, and ohmic contact layers 51 and 52 made of amorphous silicon doped with impurities are formed thereon.

Source and drain electrodes 61 and 62 made of a conductive material such as a metal are formed on the ohmic contact layers 51 and 52, and the source and drain electrodes 61 and 62 together with the gate electrode 21 are thin film transistors. (T).

Although not shown, the gate electrode 21 is connected to the gate wiring, the source electrode 61 is connected to the data wiring, and the gate wiring and the data wiring are orthogonal to each other to define the pixel region.

Subsequently, a passivation layer 70 made of a silicon nitride film, a silicon oxide film, or an organic insulating layer is formed on the source and drain electrodes 61 and 62, and the passivation layer 70 has a contact hole 71 exposing the drain electrode 62. Has

A pixel electrode 81 made of a transparent conductive material is formed in the pixel area above the passivation layer 70, and the pixel electrode 81 is connected to the drain electrode 62 through the contact hole 71.

On the other hand, the second substrate 110 is spaced apart from the first substrate 10 at a predetermined interval and disposed above the first substrate 10, and the black matrix 121 is disposed on the inner surface of the second substrate 110. ) Is formed at a position corresponding to the thin film transistor T. Although not illustrated, the black matrix 121 is formed on the entire surface of the substrate with an opening at a portion corresponding to the pixel electrode 81, and thus the pixel electrode 81 is formed. Block the light coming from other parts. The color filter 131 corresponding to the pixel electrode 81 one-to-one is formed under the black matrix 121. An overcoat layer 140 is formed below the color filter 131 to protect the color filter 131 and eliminate the step caused by the color filter, and a common electrode 150 formed of a transparent conductive material under the color filter 131. Is formed.

Although not illustrated, an alignment layer is formed on the pixel electrode 81 and the lower portion of the common electrode 150, and a liquid crystal layer 170 is injected between the alignment layers.

Such a liquid crystal display uses a backlight positioned on the back of the liquid crystal display as a light source, and light from the backlight is attenuated while passing through the liquid crystal display. Therefore, only about 3 to 8% of the incident light is transmitted, so that the screen becomes dark. In this case, in order to brighten the screen, the luminance of the transmitted light must be increased by increasing the luminance of the backlight, thereby increasing power consumption.

Accordingly, examples of modifying the structure of a color filter as a method for improving the brightness of a screen by increasing light transmittance in a liquid crystal display without increasing power consumption are disclosed in Korean Patent Nos. 1992-007615 and 1989-004377. It became.

In this case, a plurality of transmission holes are formed inside the color filter to improve light transmittance through the transmission holes. At this time, the size of the transmission holes is made fine so that it is impossible to identify with the naked eye, thereby preventing deterioration of image quality.

In this case, in order to improve the luminance of the liquid crystal display, the transparent holes must have a fine size, and the transparent holes are formed in all the color filters.

However, in general, since the human eye is less aware of the chromaticity of the blue color, the human eye is equally recognized even if the chromaticity of the blue is changed to some extent. Therefore, the blue color filter needs only to be formed to realize white light when all the red, green, and blue light are transmitted. Therefore, the brightness of the liquid crystal display can be improved while changing the structure of the blue color filter to prevent deterioration of chromaticity. have.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color filter substrate for a liquid crystal display device and a method of manufacturing the same, which can improve luminance without deteriorating chromaticity.

1 is a cross-sectional view of a general liquid crystal display device.

2 is a plan view of a color filter substrate for a liquid crystal display device according to the present invention;

3 is a cross-sectional view taken along line III-III of FIG. 2.

4A to 4F are sectional views showing the manufacturing process of the color filter substrate according to the present invention.

5 is a cross-sectional view of a mask for forming a blue color filter according to the present invention;

6 is a plan view of another color filter substrate according to the present invention;

7 is a cross-sectional view of a color filter substrate for a liquid crystal display according to a second embodiment of the present invention.

8A and 8B are cross-sectional views of a mask for forming a blue color filter according to a second embodiment of the present invention.

In the color filter substrate for a liquid crystal display device according to the present invention for achieving the above object is formed a black matrix having an opening on a transparent substrate, a color filter for implementing red, green, blue colors on the opening of the black matrix Each is formed. Subsequently, an overcoat layer is formed on the color filter, and a common electrode is formed thereon. Here, the color filter implementing the blue color has a transmission groove therein.

At this time, the area of the transmission groove is 10% to 90% of the area of the blue color filter, the blue color filter is composed of the first thickness and the second thickness of the lower portion of the transmission groove, the second thickness is 30% of the first thickness It is preferable that it is 70%.

In this case, the blue color filter is preferably made of a positive photosensitive resin.

In another color filter substrate for a liquid crystal display according to the present invention, a black matrix having an opening is formed on a transparent substrate, and color filters for implementing red, green, and blue colors are formed on the opening of the black matrix, respectively. An overcoat layer is formed on the color filter, and a common electrode is formed thereon. The color filter, which implements blue, has a through hole therein.

Here, the area of the transmission hole is preferably 30% to 70% of the blue color filter area.

In the manufacturing method of the color filter substrate for liquid crystal display devices which concerns on this invention, a black matrix which has a transparent substrate and has an opening part is formed on a transparent substrate. Subsequently, color filters for implementing red, green, and blue colors are formed on the openings of the black matrix, and an overcoat layer is formed on the color filters. Next, a common electrode is formed on the overcoat layer, and the forming of the blue color filter includes forming a transmission groove in the blue color filter.

Here, the forming of the blue color filter may include a photolithography process using a mask, and the mask may have a slit formed in a portion corresponding to the transmission groove or a semi-transmissive layer formed in the portion corresponding to the transmission groove. have.

In another method of manufacturing a color filter substrate according to the present invention, a transparent matrix is provided, and a black matrix having an opening is formed on the transparent substrate. Next, after forming a color filter for implementing red, green, and blue colors on the openings of the black matrix, an overcoat layer is formed on the color filter, and a common electrode is formed thereon. Here, forming the blue color filter includes forming a through hole in the blue color filter.

As described above, according to the present invention, a transmission hole or a groove may be formed in a blue color filter having a relatively small change in chromaticity perception to increase the transmittance of light, thereby improving luminance and preventing a decrease in chromaticity.

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

2 is a plan view of a color filter substrate for a liquid crystal display according to the present invention, and FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2.

As shown in FIGS. 2 and 3, a black matrix 220 having an opening is formed on a portion corresponding to the pixel region on the transparent insulating substrate 210. The color filters 231, 241, and 251 are formed in the pixel area above the black matrix 220 and are formed by sequentially repeating red, green, and blue colors. The edges of the color filters 231, 241, and 251 are formed. Some overlap with black matrix 220. Each color corresponds one-to-one with a pixel electrode (not shown) formed on the lower substrate, and the colors are displayed by combining the three colors. Herein, the blue color filter 251 has a transmission groove 255 formed therein such that the blue color filter 251 has a portion having a second thickness d ₂ below the transmission groove 255 and the other first thickness ( d ₁ ) is divided into parts having. Since the area and depth of the transmission groove 255 should be within a range that does not reduce the chromaticity of blue light, the area of the transmission groove 255 is preferably formed to about 10% to 90% of the area of the pixel area, the transmission groove A depth of 255 is formed such that the second thickness d ₂ is about 30% to 70% of the first thickness d ₁ . Subsequently, an overcoat layer 260 is formed on the color filters 231, 241, and 251 to protect the color filters 231, 241, and 251, and to eliminate a step caused by the color filters 231, 241, and 251. . Next, a common electrode 270 made of a transparent conductive material is formed on the overcoat layer 260.

As described above, in the present invention, a transmission groove within a predetermined range is formed inside the blue color filter, thereby increasing the transmittance of light, thereby improving luminance and not decreasing chromaticity.

A method of manufacturing the color filter substrate is illustrated in FIGS. 4A to 4D.

As mentioned above, the color filter may be manufactured by various methods. In the present invention, an example in which the pigment dispersion method is applied will be described. The pigment dispersion method is a method mainly used for forming a color filter in recent years, and a pattern is formed by coating and exposing a polyimide-based pigment dispersed material, and when using it, a color having improved light transmittance without adding a process A filter can be formed.

As shown in FIG. 4A, a black matrix 220 is formed on a transparent insulating substrate 210 such as glass. The black matrix 220 may have an opening in a portion corresponding to the pixel region, and may be made of chromium (Cr), a chromium oxide film (Cr ₂ O ₃ ), or a black resin that absorbs light.

Subsequently, as illustrated in FIG. 4B, the blue photosensitive resin 250 is coated on the black matrix 220, and then exposed using the mask 300. Here, the photosensitive resin 250 uses a positive one in which the lighted portion is removed from the development.

The mask 300 according to the present invention consists of three parts having different light transmittances. First, light is not transmitted to the region A corresponding to the first thickness (d ₁ of FIG. 3) of the blue color filter, and the transmission groove (255 of FIG. 3), that is, the second thickness of the blue color filter (FIG. 3). Only part of the light is transmitted through the region B corresponding to d ₂ ), and all of the light is transmitted through the remaining region C.

The mask is mainly formed of a light shielding film made of a chromium-like material on a transparent substrate such as a quartz substrate. In the mask 300 of FIG. 4B, a slit having a width smaller than the resolution of the exposure machine is formed in the B region. The amount of light transmitted by the diffraction phenomenon of light decreases.

Meanwhile, instead of the mask 300 of FIG. 4B, the mask 400 of FIG. 5 may be used. In the mask 400 of FIG. 5, a light shielding film 410 is formed in an area A and only partially transmits light to the B area. The transflective film 420 is formed.

Next, as illustrated in FIG. 4C, the exposed photosensitive resin (250 of FIG. 4B) is developed to form a blue color filter 251 having a transmission groove 255 therein. In this case, the area of the transmission groove 255 is about 10% to 90% of the area of the pixel area, and the depth of the transmission groove 255 is 30% of the first thickness d ₁ by the second thickness d ₂ . Form 70% or so. Accordingly, when the first thickness d ₁ of the color filter is formed at about 1.3 μm, the second thickness d ₂ is about 0.4 μm to 0.9 μm.

Next, as illustrated in FIG. 4D, a red photosensitive resin is coated, exposed, and developed to form a red color filter 231 on the pixel region. Here, a mask (not shown) used for exposure may be formed in which a light shielding film is formed only on a portion corresponding to the red color filter 231, and the red photosensitive resin in this case is positive photosensitive in which a portion exposed to light is removed. Resin is used.

In the present invention, the red color filter 231 is formed of a positive photosensitive resin, but may be formed of a negative photosensitive resin in which a portion exposed to light remains. In this case, a mask is used in which a light shielding film is formed in a region corresponding to a portion other than the red color filter 231.

Next, as shown in FIG. 4E, the green color filter 241 is formed by the same method as the red color filter 231. At this time, the green color filter 241 can use either positive photosensitive resin or negative photosensitive resin.

Here, the blue color filter 251 is formed first, and then the red and green color filters 231 and 241 are formed, but the red and green color filters 231 and 241 may be formed first.

Next, as shown in FIG. 4F, an overcoat layer 260 is formed by applying a material such as epoxy resin or polyimide to the color filters 231, 241, and 251, and indium thereon. The common electrode 270 is formed by depositing a transparent conductive material such as indium-tin-oxide or indium-zinc-oxide.

As described above, according to the present invention, a transmission groove 255 may be formed in the blue color filter 251 using the diffraction phenomenon of the light when the blue color filter 251 is patterned.

In the present invention, the method of forming the color filter by the pigment dispersion method has been described, but the same method as the dyeing method may be used, and the dyeing method also forms a color filter using a photolithography process, and thus no process is added.

Further, in the present invention, the transmission grooves are formed in one pattern in the blue color filter. As shown in FIG. 6, the transmission grooves may be formed in a plurality of quadrangles, or may be formed in a circular or other shape. As such, the shape and size of the transmission grooves are not limited, but the entire area of the transmission grooves is not within the range of 10% to 90% of the pixel area as mentioned above.

On the other hand, by forming a through hole in the blue color filter to increase the transmittance of light while preventing the decrease in chromaticity, this second embodiment of the present invention is shown in FIG.

As shown in FIG. 7, a black matrix 220 having an opening is formed on a portion corresponding to the pixel region on the transparent insulating substrate 210. The color filters 231, 241, and 251 are formed in the pixel area above the black matrix 220 and are formed by sequentially repeating red, green, and blue colors. The edges of the color filters 231, 241, and 251 are formed. Some overlap with black matrix 220. Each color corresponds one-to-one with a pixel electrode (not shown) formed on the lower substrate, and the colors are displayed by combining the three colors. Here, a transmission hole 257 is formed in the blue color filter 251 to increase the transmittance of light. At this time, the area of the transmission hole 257 should be made within a range that does not reduce the chromaticity of the blue light, it is preferable to form about 30% to 70% of the area of the pixel area. Since the blue color filter 251 does not exist below the transmission hole 257, the transmission hole 257 is formed smaller than the area of the previous transmission groove (255 of FIG. 3). Subsequently, an overcoat layer 260 is formed on the color filters 231, 241, and 251 to protect the color filters 231, 241, and 251, and to eliminate a step caused by the color filters 231, 241, and 251. . Next, a common electrode 270 made of a transparent conductive material is formed on the overcoat layer 260.

Since the color filter substrate according to the second embodiment of the present invention may be formed by the same process as the first embodiment, a description thereof will be omitted.

However, in the first embodiment, the blue color filter must be formed of a positive photosensitive resin, but in the second embodiment, both a positive photosensitive resin and a negative photosensitive resin can be used.

8A and 8B illustrate a mask used when forming a blue color filter having a transmission hole. FIG. 8A illustrates a mask 600 used when the blue color filter is formed of a positive photosensitive resin, in which a light shielding film 610 is formed only in a region D, and an area E corresponding to a transmission hole (257 in FIG. 7) and FIG. No film is formed in the remaining region F. On the other hand, in the mask 600 used when the blue color filter is formed of the negative photosensitive resin, as shown in FIG. 8B, no film is formed in the D region, and the light shielding film 710 is formed only in the E and F regions. Formed.

In addition, in the second embodiment of the present invention, as in the first embodiment, a plurality of transmission holes may be formed.

The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit of the present invention.

In the present invention, since the human eye is not sensitive to the change in the chromaticity of blue, a certain area of the transmission groove and the transmission hole are formed only in the blue color filter, thereby preventing the chromaticity from decreasing while increasing the light transmittance. Therefore, the brightness of the liquid crystal display device can be improved.

In addition, the transmission groove and the transmission hole are formed in a process such as a blue color filter so that the process is not increased.

Claims (10)

Transparent substrates; A black matrix formed on the transparent substrate and having an opening; A color filter positioned on each of the openings of the black matrix and implementing red, green, and blue colors; An overcoat layer formed on the color filter; Common electrode formed on the overcoat layer Including, The color filter for implementing the blue color filter substrate for a liquid crystal display device having a transmission groove therein. The method of claim 1, The area of the transmission groove is a color filter substrate for a liquid crystal display device of 10% to 90% of the area of the blue color filter. The method of claim 2, The blue color filter includes a first thickness and a second thickness below the transmission groove, and the second thickness is 30% to 70% of the first thickness. The method of claim 3, wherein The blue color filter is a color filter substrate for a liquid crystal display device made of a positive photosensitive resin. Transparent substrates; A black matrix formed on the transparent substrate and having an opening; A color filter positioned on each of the openings of the black matrix and implementing red, green, and blue colors; An overcoat layer formed on the color filter; Common electrode formed on the overcoat layer Including, The color filter for implementing the blue color filter substrate for a liquid crystal display device having a through hole therein. The method of claim 5, The area of the transmission hole is a color filter substrate for a liquid crystal display device 30% to 70% of the area of the blue color filter. Providing a transparent substrate; Forming a black matrix having an opening on the transparent substrate; Forming color filters on the openings of the black matrix to implement red, green, and blue colors; Forming an overcoat layer on the color filter; Forming a common electrode on the overcoat layer Including, The forming of the blue color filter may include forming a transparent groove in the blue color filter. The method of claim 7, wherein The forming of the blue color filter includes a photolithography process using a mask, wherein the mask has a slit formed in a portion corresponding to the transmission groove. The method of claim 7, wherein The forming of the blue color filter includes a photolithography process using a mask, wherein the mask has a transflective film formed on a portion corresponding to the transmission groove. Providing a transparent substrate; Forming a black matrix having an opening on the transparent substrate; Forming color filters on the openings of the black matrix to implement red, green, and blue colors; Forming an overcoat layer on the color filter; Forming a common electrode on the overcoat layer Including, The forming of the blue color filter may include forming a through hole in the blue color filter.