KR19980031798A - Planar drive type liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly, to a liquid crystal display device having an in-plane switching mode (IPS mode) and a method for manufacturing the same. A black matrix having pixels as openings is formed on one transparent insulating substrate, and a gate line and a data line are formed to form a thin film transistor. Therefore, in the planar driving liquid crystal display and the manufacturing method thereof, the black matrix is formed under the gate line and the data line to block the light of the backlight using the black matrix, thereby preventing the generation of photo-induced current. The line, the data line and the black matrix are formed on the same substrate to improve the aperture ratio of the pixel.

Description

Planar drive type liquid crystal display device and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly, to a liquid crystal display device having an in-plane switching mode (IPS mode) and a method for manufacturing the same.

The liquid crystal display is one of the most popular flat panel displays in recent years, and is a display device using an electro-optical effect of a liquid crystal material, and its driving method is largely a simple matrix type and an active matrix. It is divided into active matrix types.

In an active matrix liquid crystal display, an operation of each pixel is controlled by adding a switching element having a nonlinear characteristic to each pixel arranged in a matrix form. As a switching device, a three-terminal thin film transistor (TFT) is generally used, and a two-terminal thin film diode (TFD) such as a metal insulator metal (MIM) is also used.

In particular, the thin-film transistor liquid crystal display device which is currently being actively researched has a substrate in which a pixel electrode is formed, another substrate in which a common electrode is formed, and a liquid crystal interposed therebetween. It is made of matter. In order to drive liquid crystal molecules in such a liquid crystal display device, a method of applying a voltage to the pixel electrode and the common electrode is generally taken. In this case, a twisted-nematic (TN) method is mainly used in which liquid crystal molecules are twisted 90 ° from one substrate to another.

However, such a liquid crystal display device, particularly a liquid crystal display device using a twisted nematic liquid crystal material, depends on the angle viewed by contrast. In particular, the angle dependence of the contrast is very severe in the vertical direction.

In addition, the pixel electrode and the common electrode must be formed on different substrates, and the two substrates must be shorted in order to apply a voltage to the common electrode.

As a method for solving these problems, a liquid crystal display using a planar driving method has been proposed.

The planar driving method is a method of driving a liquid crystal display by forming both a pixel electrode and a common electrode on a substrate. Unlike a general method using a potential difference between two substrates, a planar driving method provides a potential difference within a substrate to react with liquid crystal molecules. To cause.

Next, the liquid crystal display of the conventional planar driving method will be described in detail with reference to the accompanying drawings.

1 is a plan view showing the structure of a planar driving type liquid crystal display device according to the related art, and FIGS. 2A and 2B are cross-sectional views illustrating the structure of the planar driving type liquid crystal display device shown in FIG. 1. .

As shown in FIG. 1, a gate line 3 is formed horizontally on one substrate (not shown) of a conventional flat drive type liquid crystal display, and a data line 5 perpendicular to the substrate is formed vertically. It is. Further, a rectangular common electrode line 7 composed of a portion parallel to the gate line 3 and a portion parallel to the data line 5 is formed in units of pixels. Here, the thin film transistor TFT is formed near the intersection point of the gate line 3 and the data line 5, and the gate electrode (not shown) of the thin film transistor TFT is a part of the gate line 3, The data electrode 4 is part of the data line 5. On the other hand, the source electrode 6 of the thin film transistor TFT is formed of the same material as the data line 5 and extends to form the pixel electrodes 6 and 8. The pixel electrodes 6 and 8 are composed of two vertical portions 8 parallel to the data lines 5 and two horizontal portions 6 parallel to the gate lines 3, and the two horizontal portions 6 are gate lines. It overlaps with a part of the common electrode line 7 parallel to (3), and the two vertical parts 8 are formed in both branches 71 of the common electrode line 7, respectively, and connect the two horizontal parts 6. . The vertical portions 8 of the pixel electrodes 6 and 8 cross the center of the rectangular shape formed by the common electrode line 7 and the branch 71 of the common electrode line 7.

On the other substrate (not shown), the black matrix 9 is formed while the pixels are separated from each other and intersected in the horizontal direction and the vertical direction. Here, a part of the black matrix 9 covers a part of the common electrode line 7 parallel to the gate line 3 and the data line 5, and a part of the black matrix 9 is parallel to the data line 5. A portion of the portion, the horizontal portion 6 of the source electrodes 6 and 8, the gate line 3 and the thin film transistor TFT are covered.

FIG. 2A is a cross-sectional view of part A of FIG. 1, in which a common electrode line 7 is formed at the edge of a pixel unit on one substrate 1, and a branch 71 is formed at the center thereof. The insulating film 11 covering the common electrode line 7 and the branch 71 is formed on one board | substrate 1, and the data line 5 and the vertical part 8 of the source electrode are formed in the upper part ( Formed part, see FIG. 1). And the protective film 13 which covers one board | substrate is formed.

On the other substrate 2, a black matrix 9 is formed. The black matrix 9 is formed in a portion corresponding to the common electrode line 7 and the data line 5 formed on one substrate 1.

FIG. 2B is a cross-sectional view of part B of FIG. 1, and a common electrode line formed on one substrate 1 in parallel with the gate electrode 31 and the gate line 3, which are part of the gate line 3. Part of 7) is formed in two parts. An insulating film 11 covering the gate electrode 31 and the common electrode line 7 is formed on the substrate 1, and an active layer 10 made of amorphous silicon is formed on the insulating film 11 corresponding to the gate electrode 31. It is. The data electrode 4 and the horizontal portion 6 of the source electrode connected to the data line 5 are formed on the active layer 10. As described above, the horizontal part 6 of the source electrode overlaps a part of the common electrode line 7 parallel to the gate line 3 while covering a part of the insulating film 11 and on the substrate 1 a protective film ( 13) is formed.

On the other substrate 2, a black matrix 9 is formed. The black matrix 9 is formed in a portion corresponding to the horizontal portion 6 of the thin film transistor TFT and the source electrode formed on one substrate 1.

In such a flat drive type liquid crystal display, the potential difference between the common electrode line 7 and its branches 71 and the pixel electrodes 6 and 8, in particular the common electrode line 7 and its branches 71 in the longitudinal direction, and The parallel pixel electrode 8 is used to change the direction of the liquid crystal molecules and to perform the display operation by using the change in the transmittance of light.

As a result of measuring the viewing angle characteristic using the planar driving liquid crystal display device, it is shown to be superior to the conventional liquid crystal display device.

However, in this conventional planar drive type liquid crystal display, electrode wirings are formed in the center of the display area (one pixel) made by the common electrode line 7 and its branch 71 to form an electric field parallel to the substrate. As the aperture ratio drops, the brightness of the backlight must be increased to increase the required brightness efficiency. Accordingly, there is a problem in that the light induction current increases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to provide a planar driving type liquid crystal display device having an improved aperture ratio and blocking light leakage current while securing a wide viewing angle characteristic, which is an advantage of the planar driving method.

1 is a plan view illustrating a structure of a liquid crystal display device of a planar driving method according to the related art.

2 (a) and (b) are sectional views showing the structure of the liquid crystal display device of the planar driving method in FIG.

3 is a plan view showing the structure of a liquid crystal display of a planar driving method according to an embodiment of the present invention;

4 (a) and (b) are sectional views showing the structure of a flat panel liquid crystal display device according to a first embodiment of the present invention;

5 (a) and (b) are sectional views showing the structure of a liquid crystal display device of a planar driving method according to a second embodiment of the present invention;

6A to 6E are cross-sectional views illustrating a method of manufacturing a flat panel liquid crystal display according to an embodiment of the present invention according to a process sequence thereof.

7 (a) and (e) are cross-sectional views showing the manufacturing method of the liquid crystal display device of the planar driving method according to the embodiment of the present invention in the order of their processes.

In the planar drive type liquid crystal display device for solving this problem, a gate line and a data line defining pixels are formed to cross each other on a transparent insulating substrate.

In addition, a plurality of common electrodes are formed in the pixel of the substrate, and the pixel electrode is formed parallel to the common electrode in parallel with the common electrode.

A black matrix is formed at portions except the pixel.

Here, a black matrix is formed on the substrate, and the black matrix overlaps a portion of the gate line, the data line, the common electrode, and the pixel electrode which cross each other.

In the method of manufacturing a flat panel type liquid crystal display device according to the present invention, a black matrix having pixels as openings is formed on a transparent insulating substrate, an insulating film covering the black matrix is formed, a gate line is formed on the insulating film, and the inside of the pixel is formed. The common electrode is formed in the vertical direction. Next, a gate insulating film covering the gate line and the common electrode is formed on the substrate, and an active silicon is patterned by depositing an amorphous silicon layer. Subsequently, a data line crossing the gate line is formed on the substrate, and a pixel electrode parallel to the common electrode is formed. Finally, a protective film covering the substrate is formed.

Here, the black matrix overlaps part of the gate line, the data line, the common electrode, and the source electrode.

In addition, the manufacturing method of the other flat driving type liquid crystal display device according to the present invention may be formed after forming the protective layer.

As described above, in the method of manufacturing the flat panel liquid crystal display device according to the present invention, since the black matrix is formed on the same substrate as the pixel electrode, the common electrode, the data line, and the gate line, the pixel can be formed more easily because the alignment is easy during manufacturing. Light of the backlight incident from the lower portion of the gate line, the data line, and the common electrode line is blocked by the black matrix.

Next, embodiments of the planar drive type liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice the present invention.

3 is a plan view illustrating a structure of a liquid crystal display of a planar driving method according to an exemplary embodiment of the present invention.

As shown in Fig. 3, the planar drive type liquid crystal display device according to the present invention is similar to the conventional planar drive type liquid crystal display device, but conventionally, a black matrix 9 is formed on another substrate 2, and the present invention The black matrix 90 is formed on the same substrate 10 as the gate line 30 and the data line 50. The width of the black matrix 50 formed on one substrate 10 is smaller than the width of the black matrix 9 formed on another conventional substrate 2. This is because the data line 50, the gate line 30, the common electrode line 70, and the horizontal portion 60 and the black matrix 90 of the source electrode are formed on the same substrate 10. This is because the error of alignment occurring at the time can be reduced.

4 (a) and (b) are cross-sectional views illustrating the structure of a flat panel liquid crystal display device according to a first embodiment of the present invention.

FIG. 4A illustrates a portion C of FIG. 3, wherein a black matrix 90 is formed on a portion of the substrate 10 that borders pixels, and an insulating film 120 covering the black matrix is formed. It is. A black matrix in which a common electrode line 70 is formed at an edge of a pixel unit, a branch 710 is formed in the center, and a part of the common electrode line 70 is formed on the substrate 10 on the insulating layer 120. Some overlap with 90. A gate insulating layer 110 covering the common electrode line 70 and the branch 710 is formed on one substrate 10, and the vertical portion 80 of the data line 50 and the source electrodes 60 and 80 is formed thereon. ) Is formed. The data line 50 is formed at a portion overlapping the black matrix 90, and the horizontal portion 80 of the source electrode is formed between the common electrode line 70 and the branch 710. A protective film 130 is formed to cover one substrate 10.

The other substrate 20 is provided with a color filter (not shown).

FIG. 4B is a cross-sectional view of part D of FIG. 3, in which a black matrix 90 is formed by one pixel of one substrate 10 and an insulating film 120 covering the black matrix 90 is formed. Formed. The gate electrode 310, which is a part of the gate line 30 (see FIG. 3), and a part of the common electrode line 70 formed in parallel with the gate line 30 are formed in two portions on the insulating layer 120. A gate insulating layer 110 covering the gate electrode 310 and the common electrode line 70 is formed on the substrate 10, and an active layer 100 made of amorphous silicon is formed on the insulating layer 110 corresponding to the gate electrode 310. Formed. The data electrode 40 and the horizontal portion 60 of the source electrode connected to the data line 50 (see FIG. 3) are formed on the active layer 100. As described above, the horizontal portion 60 of the source electrode overlaps a portion of the common electrode line 70 parallel to the gate line 30 while covering a portion of the gate insulating layer 110, and a passivation layer on the substrate 10. 130 is formed.

Here, the storage capacitor is formed between the horizontal 6 of the source electrode overlapping each other and a part of the common electrode line 70.

The other substrate 20 is provided with a color filter (not shown).

5 (a) and (b) are cross-sectional views illustrating the structure of a flat panel liquid crystal display device according to a second embodiment of the present invention.

5A and 5B are cross-sectional views of the second embodiment, in which a black matrix 90 is formed on the passivation layer 130 and the insulating layer 120 is not formed. In FIG. 5A, the black matrix 90 overlaps a part of the data line 50 and the common electrode line 70. In FIG. 5B, the black matrix 90 is a part of the common electrode line 70. The horizontal portion 60, the gate electrode 310, and the drain electrode 40 of the source electrode overlap each other.

The manufacturing method of the liquid crystal display of the planar driving method according to the exemplary embodiment of the present invention is performed as follows.

6A to 6E are cross-sectional views illustrating a method of manufacturing a flat panel liquid crystal display device according to an exemplary embodiment of the present invention, in accordance with a process sequence, and part C of FIG. 3 is illustrated in FIG. (A) and (e) are sectional views showing the manufacturing method of the planar driving method of the liquid crystal display device according to the embodiment of the present invention in the order of the process.

As shown in FIGS. 6 and 7 (a), in the method of manufacturing the planar driving liquid crystal display according to the exemplary embodiment of the present invention, the black matrix 90 having openings in units of pixels on the transparent insulating substrate 10 may be formed. Form.

Next, an insulating film 120 covering the black matrix 90 is formed on the substrate 10, the metal film is deposited, and patterned so as to leave only a portion overlapping the black matrix 90 and a portion dividing the center of the pixel. A branch 710 of the gate electrode 310, the common electrode line 70, and the common electrode line 70 connected to 30 (not shown) is formed (see FIGS. 6 and 7 (b)).

Subsequently, a nitride film, an amorphous silicon layer, and a heavily doped amorphous silicon layer are sequentially deposited on the substrate 10, and then the amorphous silicon layer and the heavily doped amorphous silicon layer are formed only at the portion corresponding to the gate electrode 310. Patterned so as to leave, the gate insulating film 110 and the active layer 100 are formed (see Figs. 6 and 7 (C)).

The gate insulating layer 110 may be formed as an anodic oxide film through anodization, or may be formed by laminating a multilayer film instead of a single film.

As shown in FIGS. 6 and 7 (d), a metal film is deposited on the substrate 10 and then intersects with the gate line 30 and overlaps the black matrix 90, and the branch 710 of the common electrode line 70. Pattern to re-divide the portion divided by < RTI ID = 0.0 >) and < / RTI > ) And the vertical portion 80.

Finally, the protective film 130 is formed on the substrate 10 (see FIGS. 6 and 7 (e)).

In addition, in the method of manufacturing the planar driving liquid crystal display according to the second exemplary embodiment, the black matrix 90 may be formed after the protective film 130 is formed.

Therefore, in the planar driving liquid crystal display and the manufacturing method thereof, the black matrix is formed under the gate line and the data line to block the light of the backlight using the black matrix, thereby preventing the generation of photo-induced current. The line, the data line and the black matrix are formed on the same substrate to improve the aperture ratio of the pixel.

Claims (13)

A gate line and a data line intersecting each other on a transparent insulating substrate to define a pixel, A plurality of common electrodes arranged in the pixel, A pixel electrode formed in the pixel in parallel with the common electrode; And a black matrix formed in a portion excluding the pixel. The liquid crystal display of claim 1, wherein a thin film transistor is formed at a portion where the gate line and the data line cross each other. The liquid crystal display of claim 2, wherein the black matrix is formed under the thin film transistor. The liquid crystal display of claim 2, wherein the black matrix is formed on the thin film transistor. The liquid crystal display of claim 1, wherein the black matrix is made of Cr, Mo, Ti, Ta, Al, or an alloy of Cr, Mo, Ti, Ta, and Al. The liquid crystal display of claim 1, wherein the black matrix is formed of an organic layer. The liquid crystal display of claim 1, wherein the thin film transistor is formed on the black matrix. The liquid crystal display of claim 1, wherein two or more portions of the common electrode line connecting the common electrode and a portion of the pixel electrode connecting the pixel electrode overlap to form a storage capacitor. The liquid crystal display of claim 1, wherein the black matrix overlaps a portion of the gate line, the data line, the common electrode, and the source electrode. Forming a black matrix having openings as pixels on the transparent insulating substrate, Forming an insulating film covering the black matrix, Forming a common electrode inside the pixel while forming a gate line on the insulating layer; Forming a gate insulating layer covering the gate line and the common electrode on the substrate and depositing and patterning an amorphous silicon layer to form an active region; Forming a pixel electrode parallel to the common electrode while forming a data line crossing the gate line on the substrate; Forming a passivation layer covering the substrate; Forming a common electrode at the same time as forming a gate line on the transparent insulating substrate, Forming a gate insulating layer on the substrate to cover the gate line and the common electrode; Depositing an amorphous silicon layer on the gate insulating layer to form an active region; Forming a pixel electrode in parallel with the common electrode while forming a data line intersecting the gate line to cover the pixel on the substrate; Forming a protective film covering the substrate; And forming a black matrix having the pixel as an opening on the substrate. The method of claim 11, wherein the gate insulating layer is formed in a multilayer. The method of claim 11, wherein the gate insulating layer is formed by anodization.