KR20130122824A - Liquid crystal display device and method of fabricating the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a manufacturing method thereof, capable of simultaneously compensating the color variation of a viewing angle, improving an aperture ratio, and transmittance by reducing the disclination of an electric field. The liquid crystal display device of the present invention includes: a gate line which is formed on a substrate; a data line which intersects the gate line; and a unit pixel which is composed of a plurality of subpixels at the intersections between the data line and the gate line. The data lines of a first unit pixel are tilted in a first direction. The data lines of a second unit pixel are tilted in a second direction. The first direction and the second direction are symmetrical based on the data line which is connected to the gate line between the unit pixels.

Description

Liquid crystal display and its manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE AND METHOD OF FABRICATING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a method of manufacturing the same, capable of compensating a viewing angle color deviation and reducing a field distortion region.

(PDP), Electro Luminescent Display (ELD), Vacuum Fluorescent (VFD), and the like have been developed in recent years in response to the demand for display devices. Display) have been studied, and some of them have already been used as display devices in various devices.

Among them, the liquid crystal display is the most widely used, replacing the CRT (Cathode Ray Tube) for mobile image display due to the excellent image quality, light weight, thinness, and low power consumption. In addition to the mobile use, various developments have been made for televisions and monitors for receiving and displaying broadcast signals.

The liquid crystal display includes a lower substrate on which a thin film transistor array is formed, an upper substrate on which a color filter array is formed, and a liquid crystal layer formed between the lower and upper substrates. In the lower substrate, a plurality of sub-pixels intersecting gate lines and data lines define a plurality of sub-pixels, and a plurality of pixel electrodes to which data signals are individually supplied and thin film transistors for individually driving pixel electrodes are formed. . The upper substrate is provided with a color filter formed in each sub-pixel, a black matrix for preventing light leakage, and column spacers for maintaining a gap between the lower substrate and the upper substrate.

The typical driving mode used in the above-described liquid crystal display is a twisted nematic (TN) mode in which the liquid crystal directors are arranged so that the liquid crystal directors are twisted by 90 °, and then the voltage is applied to control the liquid crystal directors. There is an in-plane switching mode in which the liquid crystal is driven by a horizontal electric field between the arranged pixel electrodes and the common electrode.

In particular, in the transverse electric field mode, the pixel electrode and the common electrode are alternately formed on the lower substrate so that the liquid crystal is aligned by the transverse electric field generated between the pixel electrode and the common electrode. By the way, the lateral field mode liquid crystal display has a wide field of view but a low aperture ratio and a low transmittance, so a fringe field switching (FFS) mode liquid crystal display has been proposed.

In the fringe field mode liquid crystal display, the pixel electrode and the common electrode form a fringe electric field with an insulating film interposed therebetween to operate the liquid crystal molecules, thereby precisely controlling the liquid crystal molecules, thereby obtaining a high contrast ratio. Compared to the transverse electric field mode liquid crystal display, high screen quality can be realized.

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

FIG. 1A is a plan view of a general liquid crystal display, and FIG. 1B is a plan view illustrating a field distortion region of the general liquid crystal display.

As shown in FIG. 1A, a general liquid crystal display device includes a plurality of gate lines GL, data lines DL, gate lines GL, and data lines DL crossing each other on a substrate to define a plurality of sub-pixels. A thin film transistor (TFT) is formed in the region. The thin film transistor TFT includes a gate electrode 10, a source, a drain electrode 13a and 13b, and a semiconductor layer 12. In particular, in the fringe field mode liquid crystal display, the pixel electrode 15 in the form of a through electrode and the common electrode 16 in the slit form an fringe electric field with an insulating film (not shown) interposed therebetween.

In this case, the fringe field liquid crystal display may compensate the viewing angle color deviation by forming the pixel electrode 15 and the common electrode 16 to be inclined. In this case, however, as shown in FIG. 1B, an electric field distortion region A in which the liquid crystal is abnormally driven due to an angle difference between the data line DL and the pixel electrode 15 is generated, and thus the transmittance of the liquid crystal display device. Is reduced.

Specifically, since the data line DL is perpendicular to the gate line GL, only the pixel electrode 15 and the common electrode 16 are formed to be inclined, so that the pixel electrode 15 and the common electrode 16 in the sub-pixel are formed. The electric field is distorted in an area not formed, that is, at an edge of the pixel area. In particular, since the pixel electrode 15 and the common electrode 16 of adjacent sub-pixels are formed symmetrically with respect to the data line DL, each sub-pixel has at least two field distortion regions A and three When the subpixels constitute one unit pixel, each unit pixel has at least six field distortion regions A. FIG.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the data wirings located in the unit pixel on the left side and the data wirings of the unit pixel on the right side are symmetrically based on the data wiring between adjacent unit pixels. An object of the present invention is to provide a liquid crystal display and a method of manufacturing the same, which are formed to reduce a field distortion region.

The liquid crystal display device of the present invention for achieving the above object is a gate wiring formed on a substrate; A data line crossing the gate line; And a unit pixel including a plurality of sub-pixels formed in each of the regions provided at the intersection of the gate line and the data line, and positioned on the left side of the data line positioned between the unit pixels connected to the same gate line. The data lines positioned in the first unit pixel are inclined in the first direction, and the data lines positioned in the second unit pixel positioned on the right side with respect to the data line are inclined in the second direction. The first direction and the second direction are symmetrical with respect to the data line.

The data line between the first unit pixel and the second unit pixel is perpendicular to the gate line.

The sub pixel may include a thin film transistor formed on the substrate; A first insulating film formed to cover the thin film transistor; A pixel electrode formed on the first insulating film and connected to the thin film transistor; A second insulating film formed on the pixel electrode; And a common electrode forming a fringe electric field with the pixel electrode with the second insulating layer therebetween.

The pixel electrode and the common electrode are inclined in a direction parallel to the data line.

In addition, the manufacturing method of the liquid crystal display device of the present invention for achieving the same object comprises the steps of forming a gate wiring on a substrate; Forming a data line crossing the gate line; And a unit pixel including a plurality of sub-pixels formed in each region formed at the intersection of the gate line and the data line, and based on the data line positioned between the unit pixels connected to the same gate line. The data lines positioned in the first unit pixel positioned on the left side are inclined in the first direction, and the data lines positioned in the second unit pixel positioned on the right side in the second unit pixel are inclined in the second direction. The first direction and the second direction are symmetrical with respect to the data line.

A data line between the first unit pixel and the second unit pixel is formed in a direction perpendicular to the gate line.

Forming a thin film transistor on the substrate; Forming a first insulating film to cover the thin film transistor; Forming a pixel electrode connected to the thin film transistor on the first insulating film; Forming a second insulating film on the pixel electrode; And forming a common electrode forming a fringe electric field with the pixel electrode with the second insulating layer therebetween.

The pixel electrode and the common electrode are formed to be inclined in a direction parallel to the data line.

The liquid crystal display of the present invention and a method of manufacturing the same according to the present invention form the pixel electrode, the common electrode, and the data wiring of the unit pixel to be inclined. In particular, the pixel electrode, the common electrode, and the data wiring of the unit pixel positioned on the left side are inclined in the first direction with respect to the data wiring, and the pixel electrode, the common electrode, and the data wiring of the unit pixel located on the right side of the unit line in the second direction. The first direction and the second direction are symmetrical with respect to the data line to reduce the field distortion area. Thereby, the aperture ratio and transmittance of the liquid crystal display device can be improved.

1A is a plan view of a general liquid crystal display device.
1B is a plan view illustrating a field distortion region of a general liquid crystal display.
2A is a plan view of the liquid crystal display of the present invention.
FIG. 2B is a cross-sectional view taken along the line II ′ of FIG. 2A;
3 is a plan view illustrating a field distortion region of the liquid crystal display of the present invention.
4A to 4F are process cross-sectional views showing manufacturing steps of the liquid crystal display device of the present invention, and FIGS. 5A and 5F are process plan views showing manufacturing steps of the liquid crystal display device of the present invention.

Hereinafter, a liquid crystal display of the present invention will be described with reference to the accompanying drawings.

FIG. 2A is a plan view of the liquid crystal display of the present invention, and FIG. 2B is a cross-sectional view taken along the line II ′ of FIG. 2A.

As shown in FIGS. 2A and 2B, the liquid crystal display of the present invention includes a gate line GL formed on the substrate 100, a data line DL intersecting with the gate line GL, a gate line GL, and data. Sub-pixels are formed in regions provided at intersections of the wirings DL, and a plurality of sub-pixels constitute one unit pixel. At this time, the data lines DL positioned in the first unit pixel on the left side are formed to be inclined in the first direction with respect to the data lines DL positioned between the unit pixels connected to the same gate line GL. The data lines DL positioned in the second unit pixel positioned on the right side of the data line DL are inclined in the second direction, and the first direction and the second direction correspond to the data line DL. It is symmetrical by reference.

Specifically, the gate line GL supplies a scan signal from a gate driver (not shown), and the data line DL supplies a video signal from a data driver (not shown). The gate line GL and the data line DL cross each other with the gate insulating layer 111 interposed therebetween to define each sub pixel, and a thin film is formed in the intersection area between the gate line GL and the data line DL of each sub pixel. The transistor TFT is formed.

The thin film transistor TFT keeps the video signal of the data line DL charged and maintained in the pixel electrode 150 in response to the scan signal of the gate line GL. The thin film transistor TFT is a semiconductor layer having a structure in which a gate electrode 110, a source electrode 130a and a drain electrode 130b spaced apart from each other, and an active layer 120a and an ohmic contact layer 120b are sequentially stacked. 120. In this case, the gate electrode 110 may protrude from the gate line GL or may be defined as a partial region of the gate line GL, as shown.

The active layer 120a overlaps the gate electrode 110 with a gate insulating layer 111 formed of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx) interposed therebetween. The ohmic contact layer 120b formed on the active layer 120a reduces the electrical contact resistance between the source and drain electrodes 130a and 130b and the active layer 120a, and the source and drain electrodes 130a and 130b. A channel is formed by removing the ohmic contact layer 120b corresponding to the spaced interval of the second contact layer 120b. The source electrode 130a is connected to the data line DL to receive the pixel signal of the data line DL, and the drain electrode 130b is formed to face the source electrode 130a at a predetermined interval with a channel therebetween. do.

First and second passivation layers 140a and 140b are sequentially formed on the entire surface of the gate insulating layer 111 to cover the thin film transistor TFT as described above. At this time, it is preferable that the first protective film 140a is an inorganic protective film, and the second protective film 140b is an organic protective film. The drain contact hole 140h formed by selectively removing the first and second passivation layers 140a and 140b exposes the drain electrode 130b and is electrically connected to the drain electrode 130b along the drain contact hole 140h. The pixel electrode 150 to be connected is formed. The pixel electrode 150 is formed in the form of a through electrode, and is formed of a transparent conductive material such as tin oxide (TO), indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), or the like.

The insulating layer 160 is formed to cover the pixel electrode 150, and the common electrode 170 is formed of the transparent conductive material as described above on the insulating layer 160. The common electrode 170 is formed in a plurality of slits to form a fringe electric field with the pixel electrode 150 with the insulating layer 160 therebetween. The liquid crystal molecules rotate by dielectric anisotropy by the fringe electric field, and the light transmittance through the sub-pixels varies according to the degree of rotation of the liquid crystal molecules, thereby realizing an image.

Although not shown, a common electrode 170 having a cylindrical electrode shape may be formed on the second passivation layer 140b, and a plurality of slit pixel electrodes 150 may be formed on the insulating layer 160. In this case, the drain contact hole 140h is formed by selectively removing the first and second passivation layers 140a and 140b and the insulating layer 160.

However, when the pixel electrode 150 and the common electrode 170 are formed to be inclined to compensate for the viewing angle color deviation as in a general liquid crystal display device, the data line DL, the pixel electrode 150, and the common electrode 170 are inclined. Due to the difference in angles, an electric field distortion (Disclination) region in which the liquid crystal is abnormally driven at the edge of the sub-pixel is generated. For this reason, the transmittance | permeability and aperture ratio of a liquid crystal display device fall.

Accordingly, in the liquid crystal display of the present invention, not only the pixel electrode 150 and the common electrode 170 but also the data line DL are formed to be inclined, thereby reducing the field distortion region.

Specifically, in the liquid crystal display of the present invention, when a plurality of sub-pixels connected to the same gate line GL form one unit pixel, the data line DL between adjacent unit pixels is connected to the gate line GL. Vertical. The data line DL in the first unit pixel positioned on the left side with respect to the data line DL is formed to be inclined in the first direction, and the second unit pixel positioned on the right side with respect to the data line DL. The data line DL is formed to be inclined in the second direction.

In particular, it is preferable that the plurality of sub pixels constituting one unit pixel are R, G, and B sub pixels, and the arrangement of the sub pixels preferably includes a G sub pixel between the R sub pixel and the B sub pixel. That is, the G subpixels have a parallelogram shape, and the R subpixels and the B subpixels have a trapezoidal shape.

In addition, the pixel electrodes 150 and the common electrodes 170 of the plurality of sub-pixels constituting the first unit pixel are also formed to be inclined in the first direction like the data line DL, and the plurality of constituting the second unit pixel is formed. The pixel electrode 150 and the common electrode 160 of the four sub pixels are also inclined in the second direction. In this case, the first direction and the second direction are symmetrical with respect to the data line DL for dividing the unit pixels, and the first direction and the second direction are about 5 ° to the data line DL for dividing the unit pixels. It has an angle of about 7 °.

3 is a plan view illustrating a field distortion region of the liquid crystal display of the present invention.

As shown in FIG. 3, the pixel electrode 150 and the common electrode 170 of the G sub pixel are formed in a direction parallel to the adjacent data line DL, so that no field distortion occurs in the G sub pixel. In addition, since the R sub pixel and the B sub pixel are adjacent to the data line DL perpendicular to the gate line GL, the R sub pixel and the B sub pixel do not have the pixel electrode 150 and the common electrode 170 formed thereon. The electric field is distorted in the region, that is, in the region adjacent to the data line DL separating the unit pixels.

That is, in the liquid crystal display of the present invention as described above, the pixel electrode 150 and the common electrode 170 in the unit pixel are formed in a direction parallel to the data line DL. Accordingly, the pixel electrode 150 and the common electrode 170 of the G sub-pixel which contributes the most to the luminance improvement compared to the center sub-pixels of the unit pixels, that is, the R sub-pixel and the B sub-pixel, are generally G sub-pixel amounts. Since it is formed in a direction parallel to the data line DL on the side, it does not have an electric field distortion (Disclination) area | region. In addition, since the electric field distortion area A is generated only at the edges of the sub pixels on both sides of the unit pixel, that is, the R sub pixel and the B sub pixel, only one electric field distortion area is included in one unit pixel.

Accordingly, the liquid crystal display of the present invention can reduce the electric field distortion region A, thereby preventing the aperture ratio and transmittance of the liquid crystal display apparatus from decreasing due to the electric field distortion region A. FIG.

In particular, in a general liquid crystal display having a resolution of 312 ppi (Pixel Per Inch), since the R, G, and B sub-pixels have two field distortion regions, all are formed in the same shape, the transmittance is the same. However, in the liquid crystal display device of the present invention having a resolution of 312 ppi, the transmittance of the R, G, and B sub pixels is higher than that of the R, G, and B sub pixels of a general liquid crystal display device. This is because in the liquid crystal display of the present invention, the G subpixel does not have an electric field distortion region, and only the R subpixel and the B subpixel have one electric field distortion region.

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

4A to 4F are process cross-sectional views showing the manufacturing steps of the liquid crystal display of the present invention, and FIGS. 5A and 5F are process plan views showing the manufacturing steps of the liquid crystal display of the present invention.

As shown in FIGS. 4A and 5A, a gate line GL and a gate electrode 110 are formed on the substrate 100. The gate electrode 110 protrudes from the gate line GL or is defined as a partial region of the gate line GL. 4B and 5B, the gate insulating film 111 is formed on the entire surface of the substrate 100 including the gate wiring GL and the gate electrode 110, and the active layer 120a is formed on the gate insulating film 111. And the ohmic contact layer 120b are sequentially formed to form a semiconductor layer 120.

4C and 5C, a data metal layer is formed on the entire surface of the gate insulating layer 111 including the semiconductor layer 120, and the data metal layer is patterned to be connected to the data wiring DL and the data wiring DL. A drain electrode 130b spaced apart from the source electrode 130a and the source electrode 130a by a predetermined interval is formed, and the ohmic contact layer 120b corresponding to the spaced interval between the source electrode 130a and the drain electrode 130b is formed. To form a channel. Although not illustrated, the semiconductor layer 120, the data line DL, the source electrode 130a, and the drain electrode 130b may be formed using one mask.

The data line DL is formed to intersect the gate line GL with the gate insulating layer 111 interposed therebetween, so that the sub-pixels are formed in each region provided at the intersection of the gate line GL and the data line DL. As a result, a thin film transistor TFT including a gate electrode 110, a gate insulating layer 111, a semiconductor layer 120, a source electrode 130a, and a drain electrode 130b is formed in each sub pixel.

In particular, a plurality of sub-pixels connected to the same gate line GL form one unit pixel, and the data line DL between adjacent unit pixels is formed to vertically cross the gate line GL. The data line DL in the first unit pixel positioned on the left side of the data line DL is inclined in the first direction and the second unit pixel positioned on the right side of the data line DL. The data wirings are formed to be inclined in the second direction. In this case, the first direction and the second direction are preferably symmetric with respect to the data line DL perpendicular to the gate line GL.

Next, as shown in FIGS. 4D and 5D, the first and second passivation layers 140a and 140b are sequentially formed to cover the thin film transistor TFT. At this time, it is preferable that the first protective film 140a is an inorganic protective film, and the second protective film 140b is an organic protective film. The first and second passivation layers 140a and 140b are selectively removed to form a drain contact hole 140h exposing the drain electrode 130b.

As shown in FIGS. 4E and 5E, a transparent conductive material such as tin oxide (TO), indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin zinc oxide (ITZO) is formed on the entire surface of the second passivation layer 140b. The transparent conductive material is patterned to form the pixel electrode 150 that is connected to the drain electrode 130b through the drain contact hole 140h. The pixel electrode 150 is formed in the form of a through-electrode, and the pixel electrode 150 in the first unit pixel is formed to be inclined in the first direction like the data line DL of the first unit pixel, and in the second unit pixel. The pixel electrode 150 is formed to be inclined in the second direction like the data line DL.

4F and 5F, the insulating layer 160 is formed to cover the pixel electrode 150, and a plurality of slit-shaped common electrodes 170 overlapping the pixel electrode 150 are formed on the insulating layer 160. To form. In this case, the common electrode 170 in the first unit pixel is formed to be inclined in the first direction like the data line DL of the first unit pixel, and the common electrode 170 in the second unit pixel also includes the data line ( DL) is formed to be inclined in the second direction.

The common electrode 170 forms a fringe electric field with the pixel electrode 150 with the insulating layer 160 interposed therebetween. The liquid crystal molecules rotate by dielectric anisotropy by the fringe electric field, and the light transmittance through the sub-pixels varies according to the degree of rotation of the liquid crystal molecules, thereby realizing an image. Although not shown, a common electrode 170 having a cylindrical electrode shape may be formed on the second passivation layer 140b, and a plurality of slit pixel electrodes 150 may be formed on the insulating layer 160.

In the liquid crystal display of the present invention as described above, the pixel electrode 150 and the common electrode 170 in the unit pixel are formed in a direction parallel to the data line DL. Accordingly, since the pixel electrode 150 and the common electrode 170 of the subpixel in the center of the unit pixel are formed in a direction parallel to the data lines DL on both sides of the subpixel, the unit pixel does not have an electric field distortion region. Since the sub-pixels on both sides of the pixel are adjacent to the data line DL perpendicular to the gate line GL, the field distortion region A is generated at the edge.

That is, the liquid crystal display of the present invention has only two field distortion regions in one unit pixel. Accordingly, the liquid crystal display of the present invention can reduce the electric field distortion region A, thereby preventing the aperture ratio and transmittance of the liquid crystal display apparatus from decreasing due to the electric field distortion region A. FIG.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Will be apparent to those of ordinary skill in the art.

DL: Data line GL: Gate line
100: substrate 110: gate electrode
111: gate insulating film 120: semiconductor layer
120a: active layer 120b: ohmic contact layer
130a: source electrode 130b: drain electrode
140a: first protective film 140b: second protective film
140h: drain contact hole 150: pixel electrode
160: insulating film 170: common electrode

Claims (8)

A gate wiring formed on the substrate;
A data line crossing the gate line; And
A unit pixel including a plurality of sub-pixels formed in each region provided at the intersection of the gate wiring and the data wiring;
The data wires positioned in the first unit pixel on the left side are formed to be inclined in a first direction with respect to the data wires positioned between the unit pixels connected to the same gate line.
The data lines positioned in the second unit pixel positioned on the right side of the data line are inclined in the second direction.
And the first and second directions are symmetrical with respect to the data line. The method of claim 1,
And a data line between the first unit pixel and the second unit pixel is perpendicular to the gate line. The method of claim 1,
The sub pixel may include a thin film transistor formed on the substrate;
A first insulating film formed to cover the thin film transistor;
A pixel electrode formed on the first insulating film and connected to the thin film transistor;
A second insulating film formed on the pixel electrode; And
And a common electrode forming a fringe electric field with the pixel electrode with the second insulating layer therebetween. The method of claim 3, wherein
And the pixel electrode and the common electrode are inclined in a direction parallel to the data line. Forming a gate wiring on the substrate;
Forming a data line crossing the gate line; And
Comprising the step of having a unit pixel consisting of a plurality of sub-pixels formed for each area provided at the intersection of the gate wiring and the data wiring,
The data lines positioned in the first unit pixel on the left side are inclined in a first direction with respect to the data lines positioned between the unit pixels connected to the same gate line,
The data lines positioned in the second unit pixel positioned on the right side of the data line are inclined in the second direction.
And the first direction and the second direction are symmetrical with respect to the data line. The method of claim 5, wherein
And forming a data line between the first unit pixel and the second unit pixel in a direction perpendicular to the gate line. The method of claim 5, wherein
Forming a thin film transistor on the substrate;
Forming a first insulating film to cover the thin film transistor;
Forming a pixel electrode connected to the thin film transistor on the first insulating film;
Forming a second insulating film on the pixel electrode; And
And forming a common electrode constituting a fringe electric field with the pixel electrode with the second insulating film interposed therebetween. The method of claim 7, wherein
The pixel electrode and the common electrode are formed to be inclined in a direction parallel to the data line.

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