KR20080032739A - Liquid crystal display device and a method of fabricating the same - Google Patents

Abstract

An LCD(Liquid Crystal Display) device and a manufacturing method thereof are provided to overlap neighboring color filters to have optical density similar to the density of a black matrix, thereby improving an aperture ratio by replacing a function of the black matrix and improving an attachment margin. Plural pixel areas are defined on a substrate. A light blocking pattern is formed in a part of a pixel area boundary. Color filters(234a,234b,234c) are respectively formed in each of the pixel areas, and overlapped as being prolonged to another part of the pixel area boundary. The color filters include RGB(Red, Green and Blue) color filters. An optical density of the overlapped color filter is higher than 3.5.

Description

Liquid crystal display device and a manufacturing method therefor {Liquid Crystal Display device and a method of fabricating the same}

1 is a cross-sectional view showing a part of a conventional liquid crystal display device.

2 is a plan view showing a part of a color filter substrate;

3 is a cross-sectional view taken along the line AA ′ of FIG. 2.

4 is a cross-sectional view illustrating a portion of a liquid crystal display according to an exemplary embodiment of the present invention.

5 is a plan view showing a color filter substrate according to the present invention.

FIG. 6 is a cross-sectional view taken along line BB ′ of FIG. 5.

<Description of Signs of Major Parts of Drawings>

210: second substrate 216: data wiring

230: first substrate 232: black matrix

234a: Red Color Filter 234b: Green Color Filter

234c: blue color filter 236: overcoat layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device (LCD), and more particularly, to a liquid crystal display device having an improved aperture ratio and a manufacturing method thereof.

As the modern society changes to information socialization, the importance of the liquid crystal display module, which is one of the information display devices, is gradually increasing. Cathode ray tube (CRT), which is widely used so far, has many advantages in terms of performance and cost, but has many disadvantages in terms of miniaturization or portability.

On the other hand, the liquid crystal display has advantages such as miniaturization, light weight, thinness, and low power consumption, thereby overcoming the disadvantages of the CRT.

Usually, a liquid crystal display device displays an image by adjusting the light transmittance of a liquid crystal using an electric field.

1 is a cross-sectional view showing a part of a conventional liquid crystal display.

As shown in FIG. 1, the conventional liquid crystal display 100 includes a color filter substrate, a thin film transistor substrate, and a liquid crystal layer. The color filter substrate is formed of chromium (Cr) or resin on the first substrate 130. A black matrix (BM) 132 is formed, and a red color filter (R) 134a, a green color filter (G) 134b, and a blue color are formed in the grid space where the black matrix 132 is formed. Filter (B) 134c is formed.

An overcoat layer 136 and a common electrode 138 formed of a transparent metal are disposed on all regions of the first substrate 130.

In the thin film transistor substrate corresponding to the color filter substrate, a plurality of gate lines (not shown) and data lines 116 intersect each other on the second substrate 110 to define a unit pixel area P. The thin film transistor TFT and the pixel electrode 129 which perform a switching operation on the pixel region P are disposed.

The thin film transistor TFT may include a gate electrode 121 protruding from the gate line, a gate insulating layer 112 formed on the gate electrode 121, and the gate insulating layer at a position of the gate electrode 121. The semiconductor layer 123 is formed on the 112.

A source electrode 125 extending from the data line 115 to a position of the gate electrode 121 on the gate insulating layer 112 and a predetermined distance from the source electrode 125 at a position of the gate electrode 121. And a drain electrode 127 formed on 112.

The semiconductor layer 123 is formed of an active layer 123a made of an amorphous silicon layer and an ohmic contact layer 123b formed under the source electrode 125 and the drain electrode 127 by being made of a silicon layer implanted with impurities. .

Further, a pattern of an active layer 123a and an ohmic contact layer 123b is further formed below the data line 123.

A passivation layer 114 is further formed on an entire surface of the second substrate 110 on which the source and drain electrodes 125 and 127 are formed, and the drain electrode 127 is formed on the pixel electrode 129 and the passivation layer 114. It is connected to each other through the formed contact hole.

In the liquid crystal display having the structure as described above, the liquid crystal molecules of the liquid crystal layer are formed by an electric field generated between the pixel electrode 129 of the second substrate 130 and the common electrode 138 of the first substrate 110. Rotate to adjust the transmittance of the light source.

2 is a plan view showing a part of a color filter substrate, and FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. 2.

As shown in FIGS. 2 and 3, a black matrix (BM: black) of chromium (Cr) or resin is formed on a portion of the first substrate 130 corresponding to the boundary of the unit pixel region and the thin film transistor TFT. A matrix 132 is formed, and a red color filter (R) 134a, a green color filter (G) 134b, and a blue color filter (B) 134c in a portion corresponding to the unit pixel region P. Is formed.

However, as the size of the liquid crystal display becomes larger, the critical dimension (CD) of the black matrix increases as the glass size of the substrate increases and the increase in bonding margin is required, which causes a problem of lowering the aperture ratio.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which can improve an aperture ratio by replacing a role of a black matrix by forming a neighboring color filter by overlapping the liquid crystal display device.

In order to achieve the above object, a liquid crystal display according to the present invention includes: a light blocking pattern in which a plurality of pixel regions are defined on a substrate and formed at a part of a boundary of the pixel region; And color filters formed in each of the plurality of pixel regions and extending to other portions of the boundary of the pixel region to overlap each other.

In addition, in order to achieve the above object, a liquid crystal display according to the present invention includes: a first substrate in which a gate line and a data line cross each other to define a pixel region, and a thin film transistor is formed at the crossing point; A second substrate facing the first substrate; A light blocking pattern formed at a position corresponding to at least one of the gate wiring and the thin film transistor on the second substrate; And color filters formed in a region corresponding to the pixel region and a region corresponding to the data line and overlapping each other at a boundary of a neighboring pixel region.

In addition, in order to achieve the above object, a method of manufacturing a liquid crystal display according to the present invention includes: defining a pixel region by crossing a gate line and a data line on a first substrate, and forming a thin film transistor at the crossing point. ; Preparing a second substrate facing the first substrate; Forming a light blocking pattern on a position corresponding to at least one of the gate line and the thin film transistor on the second substrate; And forming color filters formed in a region corresponding to the pixel region and a region corresponding to the data line and overlapping each other at a boundary between neighboring pixel regions.

Here, in the forming of the color filters formed at a position corresponding to the pixel region and overlapping each other at a boundary with a neighboring pixel region, a first color filter layer is formed and patterned on the second substrate to form a first color filter. Forming a first color filter in the pixel region; Forming and patterning a second color filter layer on the second substrate to form a second color filter overlapping the first color filter and overlapping the first color filter in a second pixel area; and a third color filter layer on the second substrate. And forming a third color filter by overlapping the second color filter and the first color filter to form a third color filter in the third pixel area.

Hereinafter, a liquid crystal display and a manufacturing method thereof according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following exemplary embodiments and has a general knowledge in the art. It will be apparent to those skilled in the art that the present invention may be embodied in various other forms without departing from the spirit of the invention. In the accompanying drawings, the dimensions of the data line, the pixel region, the color filter, the black matrix, the overcoat layer and other structures are shown in an enlarged scale than actual for clarity of the present invention. In the present invention, where the data wiring, the pixel region, the color filter, the black matrix, the overcoat layer and other structures are referred to as being formed using the terms "on", "upper", or "lower" or the like. This means that data wirings, pixel regions, color filters, black matrices, overcoat layers and other structures are formed directly over or below the data wirings, pixel regions, color filters, black matrix, overcoat layers and other structures, or otherwise. It means that data wirings, pixel regions, color filters, black matrices, overcoat layers and other structures may be further formed on the substrate.

4 is a cross-sectional view illustrating a portion of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIG. 4, the liquid crystal display 200 according to the present invention includes a color filter substrate, a thin film transistor substrate, and a liquid crystal layer. The color filter substrate is formed of chromium (Cr) on the first substrate 230. Or a black matrix (BM) 232 formed of a resin, and a red color filter (R) 234a, a green color filter (G) 234b, in a lattice space where the black matrix 232 is formed, Blue color filters (B) 234c are formed.

The red color filter 234a and the green color filter 234b overlap each other in a region corresponding to the data line 216 to be described later.

The green color filter 234b and the blue color filter 234c are also overlapped with each other in a region corresponding to the data line 216.

Although not shown, a black matrix 232 is formed in a region corresponding to the gate wiring, and a black matrix 232 is formed in a region corresponding to the thin film transistor.

Colors superimposed by overlapping color filters adjacent to each other based on the data line 216 among the red color filter (R) 234a, the green color filter (G) 234b, and the blue color filter (B) 234c The filter can be formed as an alternative to the black matrix.

The overlapped color filter is formed at a position corresponding to the data line 216 which greatly affects the aperture ratio, and the optical density corresponds to the data line 216 by replacing the black matrix by implementing 3.5 or more. Since the black matrix 232 can be removed from the region, the aperture ratio is improved while blocking light leakage.

An overcoat layer 236 and a common electrode 238 formed of a transparent metal are disposed on all regions of the first substrate 230.

However, when the structure of the liquid crystal display device is formed of both the pixel electrode and the common electrode on the second substrate as in the in-plane switching (IPS) and fringe field switching (FFS) mode liquid crystal display devices, the common electrode is the first electrode. It is not formed on the substrate.

In the second substrate 210 corresponding to the first substrate 230, a plurality of gate lines and data lines 216 intersect to define a unit pixel region P, and on the unit pixel region P The thin film transistor TFT and the pixel electrode 229 that perform the switching operation are disposed.

The thin film transistor TFT may include a gate electrode 221 protruding from the gate wiring, a gate insulating film 212 formed on the gate electrode 221, and the gate insulating film at a position of the gate electrode 221. The semiconductor layer 223 is formed on the 212.

A source electrode 225 extending from the data line 216 to a position of the gate electrode 221 on the gate insulating layer 212 and a predetermined distance from the source electrode 225 at the position of the gate electrode 212. And a drain electrode 227 formed on the 212.

The semiconductor layer 223 includes an active layer 223a formed of an amorphous silicon layer, and an ohmic contact layer 223b formed under the source electrode 225 and the drain electrode 227, which is formed of a silicon layer implanted with impurities. .

Further, a pattern of an active layer 223a and an ohmic contact layer 223b is further formed under the data line 216.

A passivation layer 214 is further formed on an entire surface of the second substrate 210 on which the source and drain electrodes 225 and 27 are formed, and the drain electrode 227 is formed on the pixel electrode 229 and the passivation layer 214. It is connected to each other through the formed contact hole.

In the liquid crystal display having the structure as described above, the liquid crystal molecules of the liquid crystal layer are formed by an electric field generated between the pixel electrode 229 of the second substrate 210 and the common electrode 238 of the first substrate 230. Rotate to adjust the transmittance of the light source.

5 is a plan view illustrating a color filter substrate according to the present invention, and FIG. 6 is a cross-sectional view taken along line BB ′ of FIG. 5.

As shown in FIGS. 5 and 6, among the red color filter (R) 234a, the green color filter (G) 234b, and the blue color filter (B) 234c, each other based on the data line 216. Adjacent color filters may be formed to overlap each other by a width of k.

The overlapping portions of the color filters are formed at positions corresponding to the data lines 216, and the optical density of the overlapped color filters is 3.5 or more to replace the black matrix, thereby replacing the black lines. Since the black matrix can be removed in the area corresponding to 216, the aperture ratio is improved while blocking light leakage.

In addition, since the light blocking area is defined by overlapping the neighboring color filters, the decrease in the aperture ratio, which may be caused by the increase of the black matrix critical dimension (CD) due to the increase in the bonding margin, may be reduced.

7A to 7G are flowcharts illustrating a method of manufacturing a color filter substrate of a liquid crystal display according to the present invention.

First, a light blocking material is applied to the entire surface of the substrate to form a light blocking layer. As the light blocking material, a light blocking metal or a light blocking resin including chromium (Cr) is used.

Subsequently, the light blocking layer is patterned by a photolithography process using a first mask to form a black matrix 232 as shown in FIG. 5.

The black matrix 232 may be formed in a region corresponding to the gate line and the thin film transistor region.

As shown in FIGS. 7A and 7B, after the red resin is entirely deposited on the substrate on which the black matrix 232 is formed, the red resin is patterned by a photolithography process using a second mask. 234a is formed.

As shown in FIGS. 7C and 7D, after the green resin is entirely formed on the substrate on which the red color filter (R) 234a is formed, the green resin is patterned by a photo process using a third mask. G) 234b is formed.

In this case, the green color filter 234b may be formed to overlap the red color filter 234a with a predetermined width k, and the overlapped area may be an area corresponding to the data line 216. .

As shown in FIGS. 7E and 7F, after the blue resin is entirely formed on the substrate on which the green color filter (G) 234b is formed, the blue resin is patterned by a photo process using a fourth mask. B) 234c is formed.

The blue color filters (B) 234c are formed to have a predetermined width (k) with neighboring green color filters (G) 234b and red color filters (R) 234a, and the overlapped area is a data line 216. It is desirable to make the area correspond to

As illustrated in FIG. 7G, an overcoat layer 236 and a common electrode 238 formed of a transparent metal are disposed on all regions of the substrate 230.

As mentioned above, although the present invention has been described in detail through specific embodiments, the present invention has been described in detail, and the liquid crystal display and the manufacturing method according to the present invention are not limited thereto, and the present invention is not limited thereto. It is apparent that modifications and improvements are possible by those skilled in the art.

The present invention has an effect of improving the aperture ratio and the bonding margin by replacing the role of the black matrix by overlapping the neighboring color filters in the color filter substrate of the liquid crystal display to have an optical density of about the black matrix.

Claims (12)

A light blocking pattern on the substrate, the plurality of pixel regions being defined and formed at a portion of the pixel region boundary; And And color filters formed in each of the plurality of pixel regions and extending to other portions of the pixel region boundary to overlap each other. The method of claim 1, And the color filters include red, green, and blue color filters. The method of claim 1, And an optical density of the superimposed color filter is 3.5 or more. A first substrate on which a gate line and a data line cross each other to define a pixel area, and a thin film transistor connected to the gate line and the data line at the intersection point; A second substrate disposed opposite the first substrate; A light blocking pattern formed on a region corresponding to at least one of the gate wiring and the thin film transistor on the second substrate; And And color filters formed in a region corresponding to the pixel region and a region corresponding to the data line and overlapping each other at a boundary between neighboring pixel regions. The method of claim 4, wherein And the color filters include red, green, and blue color filters. The method of claim 4, wherein And an optical density of the overlapped color filter is 3.5 or more. The method of claim 4, wherein And color filters formed by overlapping each other at a boundary with the neighboring pixel region. Forming a pixel region by crossing gate lines and data lines on a first substrate, and forming a thin film transistor connected to the gate lines and the data lines at the crossing points; Preparing a second substrate facing the first substrate; Forming a light blocking pattern on an area corresponding to at least one of the gate line and the thin film transistor on the second substrate; And And forming color filters formed in a region corresponding to the pixel region and a region corresponding to the data line and overlapping each other at a boundary of a neighboring pixel region. The method of claim 8, And the color filters include red, green, and blue color filters. The method of claim 8, The optical density of the overlapped color filter is 3.5 or more. The method of claim 8, The color filters formed by overlapping each other at a boundary with the neighboring pixel region are different indices. The method of claim 8, Forming color filters formed at positions corresponding to the pixel regions and overlapping each other at a boundary with a neighboring pixel region; Forming and patterning a first color filter layer on the second substrate to form a first color filter in a first pixel region; Forming and patterning a second color filter layer on the second substrate to form a second color filter overlapping the first color filter and in a second pixel area; and Forming a third color filter layer on the second substrate and patterning the third color filter layer to form a third color filter in a third pixel region and overlapping the second color filter and the first color filter. The manufacturing method of the liquid crystal display device.

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