KR20110024597A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to reduce error related to rubbing due to a column spacer and transmittance by forming a dual columns spacer. CONSTITUTION: A second substrate is attached to a first substrate. A data line and a gate line(13) are horizontally arranged to the first substrate. A thin film transistor is formed in a pixel area. A pixel electrode is electrically connected to the thin film transistor. A black matrix blocks the light which is formed on a second substrate. An overcoat layer is formed on the second substrate including a plurality of color filters.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, a step of giving a color pigment in a region sufficiently covered by a black matrix to position a column spacer, thereby forming a double column spacer at this portion, thereby reducing transmittance and The present invention relates to a liquid crystal display device having improved rubbing-related defects.

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 (ELDs), and vacuum fluorescent (VFD) Various flat panel display devices have been studied, and some are already used as display devices in various equipments.

Among them, LCD is the most widely used as the substitute for CRT (Cathode Ray Tube) for the use of mobile image display device because of the 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.

In this regard, a liquid crystal display device having a double column spacer according to the related art will be described with reference to FIGS. 1 and 2 as follows.

1 is a schematic plan view of a liquid crystal display according to the prior art.

FIG. 2 is a schematic cross-sectional view of the liquid crystal display device taken along the line II-II of FIG. 1.

Referring to FIG. 1, a liquid crystal display according to the related art includes a TFT array substrate 11 having a gate line 13, a data line 21, a thin film transistor (not shown), and a pixel electrode 27; The color filter substrate 31 on which the black matrix 33, the color filters 35R and 35G, and the overcoat layer 37 are stacked, and the TFT array substrate 11 and the color filter bonded together by a failure turn (not shown). It comprises a liquid crystal layer (not shown) formed between the substrate 31.

Here, the first column spacer 39 for maintaining the cell gap and the second column spacer 41 for preventing the gap are formed at regular intervals on the color filter substrate 31.

The first column spacer 39 is formed in contact with the TFT array substrate 11 at a portion of the color filter substrate 31 corresponding to the channel region of the thin film transistor formed in the green sub-pixel (G cell) region.

In addition, the second column spacer 41 for preventing leakage contacts the TFT array substrate 11 to a portion of the color filter substrate 31 corresponding to the gate line 13 formed in the red sub-pixel (R cell) region. It is formed so as to be spaced apart at regular intervals.

In this case, a red color filter 35R and a green color filter 35G are formed on the color filter substrate 131 on which the first column spacer 39 and the second column spacer 41 for preventing pressure are formed.

On the other hand, on the TFT array substrate 11, the gate line 13 and the data line 21 are arranged to cross each other, and the gate line 13 and the data line 21 cross each other to define a pixel area. A thin film transistor (not shown) is formed in the portion, and a pixel electrode (see 27 in FIG. 1) is formed in each pixel region.

Here, a gate line 13 having a gate electrode 13a is formed on the TFT array substrate 11, and a gate insulating film 15 is formed on the entire surface of the substrate including the gate line 13.

In addition, the semiconductor layer 17 is formed on the gate insulating layer 15 on the gate electrode 13a and the data line 21 is formed on the gate insulating layer 15 in a direction perpendicular to the gate line 13. And a source electrode 21a and a drain electrode 21b are formed so as to branch from the data line 21 crossing the gate line 13 and overlap both sides of the semiconductor layer 17. A protective film 23 is formed on the entire surface of the substrate including the ().

Although not shown in FIG. 2, a contact hole (see 25 in FIG. 1) is formed in the drain electrode 21b to form a pixel electrode (see 27 in FIG. 1) in the pixel region.

In addition, a black matrix 33, color filters 35R and 35G, and an overcoat layer 37 are formed on the color filter substrate 31, and the overcoat layer 37 of a portion corresponding to the channel region of the thin film transistor is formed. A first column spacer 39 is formed thereon, and a second column spacer 41 for preventing pressure is formed on the overcoat layer 37 overlapping the color filter 35G corresponding to the gate line 13. .

However, the liquid crystal display device having the column spacer according to the related art has the following problems.

When the liquid crystal display device having the column spacer according to the related art is subjected to rubbing in the vertical or diagonal direction, the area of the column spacer opposite to the rubbing direction may not be easily rubbed due to the step of the column spacer. Liquid crystals do not align in this region, and light leakage defects (ie, rubbing tails) occur.

Therefore, in the prior art, when such defects are severe, the black matrix should be blinded. If the black matrix is expanded for the blind design, the transmittance is reduced. In particular, if it does not appear as a bad phenomenon on the screen, it is left alone, but a problem in image quality such as reduction of the contrast ratio CR occurs.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, the object of the present invention is to give a step to the color pigment in the region that is sufficiently occluded by the black matrix position of the column spacer to the double column spacer The present invention provides a liquid crystal display device which can improve the transmittance and rubbing related defects caused by column spacers.

According to an aspect of the present invention, a liquid crystal display device includes: a first substrate and a second substrate bonded to correspond to the first substrate; A plurality of gate lines and a plurality of data lines arranged vertically on the first substrate to define a plurality of pixel regions; A thin film transistor formed in each pixel area defined by the plurality of gate lines and the plurality of data lines; A pixel electrode formed on the first substrate and electrically connected to the thin film transistor; A black matrix formed on the second substrate to block light; A color filter formed on a second substrate corresponding to the plurality of pixel regions including the black matrix and having a stepped portion at a portion corresponding to any one channel region of the thin film transistors formed in each of the adjacent pixel regions; A plurality of color filters comprising; An overcoat layer formed on the second substrate including the plurality of color filters; A first column spacer formed on an overcoat layer formed in a color filter portion corresponding to any one channel region among thin film transistors formed in each of the adjacent pixel regions; A second column spacer formed on an overcoat layer formed on a stepped portion of another color filter corresponding to another channel region among thin film transistors formed in each of the adjacent pixel regions; And a liquid crystal layer formed between the first substrate and the second substrate.

According to the liquid crystal display device according to the present invention has the following advantages.

In the liquid crystal display device according to the present invention, a sufficiently secured black matrix (BM) capable of preventing rubbing tails by patterning the existing R, G, and B regions and arranging column spacers at the stepped portions. Only the region can be used to form the double column spacer. In particular, when the black matrix area is smaller than the rubbing tail, a problem of light leakage or CR degradation due to the rubbing tail may occur regardless of the size of the pixel. However, when the size of the pixel is large, the black matrix area is larger than the rubbing tail. Therefore, even if the problem of light leakage or CR degradation due to the rubbing tail is small, the rate of decrease in transmittance is not a problem. However, the smaller the size of the pixel, the larger the rate of decrease in transmittance, so that the present invention can be effectively applied.

Accordingly, the present invention can improve the transmittance and rubbing related defects caused by the column spacer by giving a step to the color pigment in a region sufficiently masked by the black matrix to position the column spacer.

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

3 is a schematic plan view of a liquid crystal display according to the present invention.

4 is a schematic cross-sectional view of the liquid crystal display device taken along the line IV-IV of FIG. 3.

Referring to FIG. 3, a liquid crystal display according to the present invention includes: a TFT array substrate 101 having a gate line 103 and a data line 121, a thin film transistor, and a pixel electrode 127; The color filter substrate 131 on which the black matrix layer 131, the color filters 135R and 135G, and the overcoat layer 137 are stacked, and the TFT array substrate 101 and the color bonded to each other by a failure turn (not shown) It is configured to include a liquid crystal layer (not shown) formed between the filter substrate 131.

Here, the first column spacer 139 for maintaining the cell gap and the second column spacer 141 for preventing the gap are formed at regular intervals on the color filter substrate 131.

The first column spacer 139 is formed to contact the TFT array substrate 101 at a portion of the color filter substrate 131 corresponding to the channel region of the thin film transistor formed in the green sub-pixel (G cell) region.

In addition, the second column spacer 141 for preventing pressing contacts the TFT array substrate 101 to a portion of the color filter substrate 131 corresponding to a channel region of a thin film transistor formed in a red sub-pixel (R cell) region. It is formed so as to be spaced apart at regular intervals.

In this case, the pressing preventing second column spacer 141 is formed on the color filter substrate 131 corresponding to the channel region of the thin film transistor, and the black matrix of the color filter substrate 131 corresponding to the channel region of the thin film transistor. The red color filter 135R is not formed on the 133. That is, the red color filter 135R is formed in an area excluding the black matrix 133 of the color filter substrate 131 corresponding to the channel area of the thin film transistor formed in the red sub-pixel (R cell) area. .

Therefore, a pigment step is formed on a portion of the black matrix 133 of the color filter substrate 131 corresponding to the channel region of the thin film transistor in which the second column spacer 141 for preventing pressing is formed.

In this case, the first column spacer 139 and the second column spacer 141 are alternately arranged in a plurality of subpixel regions. In addition, the first column spacer 139 and the second column spacer 141 may be formed not only in the green subpixel (Gcell) and the red subpixel (Rcell) but also in the blue subpixel (Bcell). It does not need to be limited to what is formed in any one pixel.

On the other hand, on the TFT array substrate 101, the gate line 103 and the data line 121 are arranged to cross each other, and the gate line 103 and the data line 121 cross each other to define a pixel area. A thin film transistor (not shown) is formed in the portion, and a pixel electrode (see 127 of FIG. 3) is formed in each pixel region.

Referring to FIG. 4, a gate line 103 having a gate electrode 103a is formed on the TFT array substrate 101, and a gate insulating film 105 is formed on the entire surface of the substrate including the gate line 103. Is formed.

In addition, a semiconductor layer 107 is formed on the gate insulating layer 105 above the gate electrode 103a, and a data line 121 is formed on the gate insulating layer 105 in a direction perpendicular to the gate line 103. And a source electrode 121a and a drain electrode 121b are formed to branch from the data line 121 crossing the gate line 103 so as to overlap both sides of the semiconductor layer 107. The passivation layer 123 is formed on the entire surface of the substrate including the 121.

Although not shown in FIG. 4, a contact hole (see 125 in FIG. 3) is formed in the drain electrode 121b to form a pixel electrode (see 127 in FIG. 3) in the pixel region.

Here, the first and second column spacers 139 and 141 are not limited to being in contact with the TFT array substrate 101 at a portion corresponding to an upper side of the channel region of the thin film transistor, and are corresponding to a region of the thin film transistor. It can be formed if. That is, a color filter corresponding to an upper side of the source electrode 121a, an upper side of the drain electrode 121b, an upper side of the gate electrode 103a, or an upper side of a portion where the drain electrode 121b and the pixel electrode 127 are in contact with the thin film transistor. The first and second column spacers 139 and 141 may be formed on a portion of the substrate 131.

In addition, a black matrix 133, color filters 135R and 135G, and an overcoat layer 137 are formed on the color filter substrate 131, and the overcoat layer 137 of a portion corresponding to the channel region of the thin film transistor is formed. The first column spacer 139 is formed on the second column spacer for preventing the pressing on the overcoat layer 137 formed on the portion corresponding to the channel region of the thin film transistor and the color filter 135R is not formed. 141 is formed.

In this case, a black matrix 133 is formed on the color filter substrate 131, and red, green, and blue color filters 135R, 135G, and the like are disposed on the color filter substrate 131 including the black matrix 133. Is formed. The red, green, and blue color filters 135R, 135G, and the like are formed using photolithography processing technology, inkjet printing technology, or other known technology.

Here, a method of forming the red, green, and blue color filters 135R, 135G, and not shown using the photolithography process technology will be briefly described with reference to FIG. 4.

First, as shown in FIG. 4, after the green (G) pigment is applied onto the color filter substrate 131 including the black matrix 133, the green (through exposure and developing process using photolithography process technology) G) The pigment is selectively patterned to form a green color filter 135G in the green (G) subpixel region. In this case, the green color filter 135G is formed in a region corresponding to the gate line 103 and the data line 121 including a portion corresponding to the channel region of the thin film transistor.

Then, after applying a red (R) pigment on the color filter substrate 131 including the green color filter 135G and the black matrix 133, the red (R) through the exposure and development process using a photolithography process technology. ) The pigment is selectively patterned to form a red color filter 135R in the red (R) subpixel region. In this case, the red color filter 135R is formed in a region excluding a portion corresponding to the channel region of the thin film transistor. That is, the color filter 135R is not formed in the portion corresponding to the channel region of the thin film transistor.

Subsequently, the process of forming the blue color filter (not shown) also proceeds to the same process as the process of forming the red and green color filters 135R and 135G. The neighboring red and green color filters 135R and 135G, The green and blue color filters or the blue and red color filters are formed in a group and are alternately formed. That is, no color filter of any one of the neighboring red and green color filters, the green and blue color filters, or the blue and red color filters is formed on the color filter substrate positioned in the portion corresponding to the channel region of the neighboring thin film transistors. . For example, as shown in FIG. 4, the red color filter 135R is formed in an area excluding a portion corresponding to the channel region of the thin film transistor, and the neighboring green color filter 135G is formed of the neighboring thin film transistor. It is also formed in a portion corresponding to the channel region.

Accordingly, a first column spacer 139 is formed in the green color filter 135G region corresponding to the channel region of the thin film transistor positioned in the green subpixel G region to maintain the cell gap while being in contact with the transistor.

In addition, a second column spacer 141 for preventing pressing is formed on the color filter substrate 131 which is a portion corresponding to the channel region of the thin film transistor and on which the red color filter 135R is not formed. In this case, the pressing preventing second column spacer 141 is not formed in direct contact with the color filter substrate 131, but is formed thereon after the overcoat layer 137 is formed.

Next, although not shown in the drawings, an alignment film (not shown) is formed on each of the TFT array substrate 101 and the color filter substrate 131 as described above, and then subjected to a rubbing process, whereby the first column spacer 139 is used. The TFT array substrate 101 and the color filter substrate 131 are bonded to each other to maintain a cell gap.

As described above, the red, green, and blue color filters are patterned to form the second column spacer for preventing the pressing on the stepped portion, that is, the portion where the color filter is not formed, thereby sufficiently securing the black to prevent the rubbing tail. Only columnar regions may be used to form column spacers.

In particular, when the black matrix area is smaller than the rubbing tail, a problem of light leakage or CR degradation due to the rubbing tail may occur regardless of the size of the pixel. However, when the size of the pixel is large, the black matrix area is larger than the rubbing tail. Therefore, even if the problem of light leakage or CR degradation due to the rubbing tail is small, the rate of decrease in transmittance is not a problem. However, the smaller the size of the pixel, the larger the rate of decrease in transmittance, so that the present invention can be effectively applied.

Therefore, the present invention can provide a step in the pigment in the region sufficiently occluded by the black matrix to position the position on the column spacer to form a double column spacer in this portion, thereby reducing the transmittance and rubbing related defects caused by the column spacer.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

Accordingly, the scope of the present invention is not limited thereto, but various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims are also within the scope of the present invention.

1 is a schematic plan view of a liquid crystal display according to the prior art.

FIG. 2 is a schematic cross-sectional view of the liquid crystal display device taken along the line II-II of FIG. 1.

3 is a schematic plan view of a liquid crystal display according to the present invention.

4 is a schematic cross-sectional view of the liquid crystal display device taken along the line IV-IV of FIG. 3.

*** Explanation of symbols on the main parts of the drawing ***

101 TFT array substrate 103 gate line

103a: gate electrode 105: gate insulating film

107: semiconductor layer 121: data line

121a: source electrode 121b: drain electrode

123: protective film 125: contact hole

127: pixel electrode 131: color filter substrate

133: black matrix 135R: red color filter

135G: Green color filter 137: Overcoat layer

139: first column spacer 141: second column spacer

Claims (9)

A second substrate bonded to the first substrate and the first substrate; A plurality of gate lines and a plurality of data lines arranged vertically on the first substrate to define a plurality of pixel regions; A thin film transistor formed in each pixel area defined by the plurality of gate lines and the plurality of data lines; A pixel electrode formed on the first substrate and electrically connected to the thin film transistor; A black matrix formed on the second substrate to block light; A color filter formed on a second substrate corresponding to the plurality of pixel regions including the black matrix and having a stepped portion at a portion corresponding to any one channel region of the thin film transistors formed in each of the adjacent pixel regions; A plurality of color filters comprising; An overcoat layer formed on the second substrate including the plurality of color filters; A first column spacer formed on an overcoat layer formed on a color filter portion corresponding to any one channel region of the thin film transistors formed in each of the adjacent pixel regions; A second column spacer formed on an overcoat layer formed on a stepped portion of another color filter corresponding to another channel region among thin film transistors formed in each of the adjacent pixel regions; And And a liquid crystal layer formed between the first substrate and the second substrate. The liquid crystal display of claim 1, wherein the first column spacer is formed to contact the first substrate. The liquid crystal display of claim 1, wherein the second column spacer is formed to be spaced apart from the first substrate. The liquid crystal display of claim 1, wherein the second column spacer is formed on an overcoat layer overlapping the black matrix positioned at a stepped portion of the another color filter. The liquid crystal display of claim 1, wherein the first and second column spacers are formed on an overcoat layer corresponding to a channel region of the thin film transistor. The method of claim 1, wherein the adjacent color filters of the plurality of color filters (R, G, B) include red and green color filters, green and blue color filters, or blue and red color filters that are adjacent to each other. Liquid crystal display characterized in that. 7. The liquid crystal display device according to claim 6, wherein any one of the adjacent red and green color filters, the green and blue color filters, or the blue and red color filters has a stepped portion. 8. The liquid crystal display device according to claim 7, wherein the stepped portion of the color filter corresponds to any one channel region of the thin film transistors formed in each of the adjacent pixel regions. The method of claim 8, wherein the stepped portion of the one color filter overlaps the stepped portion of the one color filter corresponding to any one channel region of the thin film transistors formed in each of the adjacent pixel regions. A second column spacer is formed on the overcoat layer to be formed.

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