KR20130022732A - Contact structure of line and lcd including the same - Google Patents

Abstract

PURPOSE: A line contact structure and an LCD including the same are provided to prevent the deterioration of image quality. CONSTITUTION: A pixel electrode(222) includes a guide groove(300) for exposing a part of a contact hole(216a). A first alignment layer is formed in the front surface of a first substrate. A second alignment layer is formed in a second substrate. A liquid crystal layer is formed in a space between the first and the second alignment layer.

Description

Wiring contact structure and liquid crystal display including the same {Contact structure of line and LCD including 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 wiring contact structure capable of preventing the phenomenon of the alignment material from slipping and a liquid crystal display device including the same.

With the recent development of the information society, the necessity of a display device having excellent characteristics such as thinning, light weight, and low power consumption has emerged. Accordingly, research on flat panel displays has been actively conducted. Liquid crystal displays are excellent in resolution, color display, image quality, etc., and are being actively applied to monitors of notebook computers and desktop computers.

A liquid crystal display device is a surface facing each other with a liquid crystal layer interposed therebetween and a liquid crystal panel in which a pair of transparent insulating substrates on which a field generating electrode is formed, is bonded to each other, and an essential component is formed between the two field generating electrodes. According to the electric field size of, the arrangement direction of the liquid crystal molecules interposed therebetween is artificially adjusted and accordingly, various images are displayed by changing the transmittance of light.

A configuration of the liquid crystal display will be described in more detail with reference to FIG. 1, which is a cross-sectional view of a general liquid crystal display.

As shown in the figure, the liquid crystal panel 10 having an array substrate and a color filter substrate facing each other with the liquid crystal layer 5 interposed therebetween and a backlight disposed below the liquid crystal panel 10 20, a pixel region P is defined on one surface of the first substrate 1, which is called a dual array substrate, and a thin film transistor T is provided in each pixel region P so that each pixel region ( One-to-one correspondence is connected to the transparent pixel electrode 12 provided in P).

In addition, the second substrate 2 facing the liquid crystal layer 5 therebetween is called an upper substrate or a color filter substrate, and on one surface thereof, a thin film transistor T of the first substrate 1, etc. A grid-like black matrix 21 is formed to surround the pixel region P so as to expose only the pixel electrode 12 while covering the non-display element of.

In addition, transparent common electrodes covering R (red), G (green), and B (blue) color filters 23 and all of which are sequentially and repeatedly arranged in correspondence to each pixel region P in the lattice. (25).

At this time, the outer surfaces of the first and second substrates 1 and 2 are attached with polarizing plates 30 and 40 for selectively transmitting only specific polarized light.

The liquid crystal layer 5 is interposed between the pixel electrode 12 and the common electrode 25 by interposing first and second alignment layers 50a and 50b in which surfaces facing the liquid crystal are rubbed in a predetermined direction, respectively. Evenly align the initial alignment of the molecules with the orientation.

In addition, a seal pattern 60 is formed along the edges of both substrates 1 and 2 to prevent leakage of the liquid crystal layer 5 filled therebetween.

Meanwhile, in the liquid crystal display device, the pixel electrode 12 formed on the first substrate 1 comes into contact with the drain electrode 19 of the thin film transistor T through the contact hole 16. Since the pixel electrode 12 is patterned and positioned around the hole 16, a step is generated around the contact hole 16 by the pixel electrode 12.

As such, a step is formed around the contact hole 16 by the pixel electrode 12, so that the alignment material is formed on the pixel electrode 12 in the process of forming the first alignment layer 50a on the first substrate 1. Due to the step by step, it is not applied to the contact hole 16, thereby causing a problem that the alignment material is not uniformly applied on the substrate (1).

Therefore, the initial molecular arrangement of the liquid crystal of the liquid crystal layer 5 cannot be determined in the region where the contact hole 16 is formed, and light leakage occurs through the region, and the light leakage is particularly black in the pixel region P. If black is implemented, it is observed as a large defect, which degrades the screen display quality of the LCD.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to allow an alignment layer material to be applied into a contact hole of a liquid crystal display.

Accordingly, the second object is to improve the screen display quality of the liquid crystal display device.

In order to achieve the object as described above, the present invention comprises a first substrate including a gate wiring and a data wiring, and a thin film transistor; A protective layer including a contact hole exposing the drain electrode of the thin film transistor; A pixel electrode formed on the protective layer and including a guide groove which contacts the drain electrode through the contact hole and exposes a part of an edge of the contact hole; A first alignment layer formed on an entire surface of the first substrate including the pixel electrode; A second substrate facing the first substrate and having a second alignment layer formed thereon; A liquid crystal layer formed in the spaced space between the first and second alignment layers; A common electrode formed on one selected from the first substrate and the second substrate, the common electrode forming an electric field with the pixel electrode, and the alignment material forming the first alignment layer is guided into the contact hole through the guide groove; A liquid crystal display device is provided.

In this case, the guide groove is formed at an edge of the pixel electrode corresponding to the edge of the contact hole, and the edge of the contact hole is rounded.

In addition, the alignment material is applied onto the first substrate through an inkjet coating method, and the speed at which the alignment material is guided into the contact hole is adjusted by adjusting the width of the guide groove.

In addition, the present invention is a substrate formed with a first wiring; An insulating material formed on the substrate and including a contact hole exposing the first wiring; A second wiring formed on the insulating material and including a guide groove contacting the first wiring through the contact hole and exposing a portion of an edge of the contact hole; A wiring contact structure is formed on the front surface of the substrate including the second wiring, and includes a liquid material layer applied into the contact hole through the guide groove.

In this case, the guide groove is formed at the edge of the second wiring corresponding to the edge of the contact hole, and the edge of the contact hole is rounded.

As described above, in the process of forming the alignment layer on the substrate by forming a guide groove exposing a portion of the edge of the drain contact hole on the edge of the pixel electrode corresponding to the edge of the drain contact hole according to the present invention, the alignment material is drained There is an effect that can be applied to the inside of the contact hole.

Through this, there is an effect that can prevent the generation of light leakage, there is an effect that can prevent the problem that the screen display quality of the liquid crystal display device is degraded.

1 is a cross-sectional view schematically showing a general liquid crystal display device.
2 is an exploded perspective view schematically illustrating a configuration of a liquid crystal display according to an exemplary embodiment of the present invention.
3 is a cross-sectional view schematically showing a cross section of the first substrate of FIG.
4A is a plan view schematically illustrating a connection between a general pixel electrode and a drain electrode;
4B is a plan view schematically illustrating a connection between a pixel electrode and a drain electrode according to an exemplary embodiment of the present invention.
5A-5B are cross-sectional views schematically showing cross sections taken along lines A and B of FIGS. 4A and 4B.
6 is a plan view schematically illustrating a connection between a pixel electrode and a drain electrode according to another exemplary embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

2 is an exploded perspective view schematically illustrating a configuration of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in the figure, the liquid crystal panel 110 in which an array substrate 112 and a color filter substrate 114 face each other with the liquid crystal layer 105 interposed therebetween is an essential element. do.

A plurality of data lines 218 and gate lines 221 vertically and horizontally cross each other on one surface of the first substrate 112, called a lower substrate or an array substrate, to define the pixel area P.

A thin film transistor T is provided at an intersection point of the two wires so as to correspond one-to-one with the transparent pixel electrode 222 provided in each pixel region P. FIG.

The second substrate 114 facing the liquid crystal layer 105 with the liquid crystal layer 105 interposed therebetween is referred to as an upper substrate or a color filter substrate, and one surface thereof has a data line 218 of the first substrate 112. A lattice-like black matrix 231 is formed around the pixel region P to cover only the pixel electrode 222 while covering the non-display elements such as the gate wiring 211 and the thin film transistor T.

In addition, a transparent common electrode 235 covering R (red), G (green), and B (blue) color filters 233 sequentially arranged to correspond to each pixel region P in the lattice. It includes.

Although not clearly shown in the drawings, the first and second alignment layers for determining the initial molecular alignment direction of the liquid crystal are interposed between the two substrates 112 and 114 and the liquid crystal layer 105, and filled therebetween. Seal patterns are formed along edges of both substrates 112 and 114 to prevent leakage of the liquid crystal layer 105.

In addition, since the first substrate 112 has a larger area than the second substrate 114, the edges of the first substrate 112 are exposed to the outside when they are bonded to each other, and each of the plurality of data lines 218 and A plurality of data pads 218a connected to each other and a plurality of gate pads (not shown) connected to the plurality of gate wirings 211 are positioned.

Accordingly, the on / off signal of the thin film transistor T is sequentially scanned and applied to the gate wiring 211 so that the image of the data wiring 218 is applied to the pixel electrode 222 of the selected pixel region P. FIG. When the signal is transmitted, the liquid crystal molecules are driven by the vertical electric field between the common electrode 235 and the pixel electrode 222, and various images can be displayed by the change in the transmittance of light.

In addition, first and second polarizing plates 130 and 140 for selectively transmitting only specific light are attached to each outer surface of the liquid crystal panel 110. The first polarizing plate 130 has a polarization axis in a first direction. The second polarizing plate 140 has a polarization axis in a second direction perpendicular to the first direction.

In addition, a backlight 120 is provided to supply light from the rear surface of the liquid crystal panel 110 so that the difference in transmittance is expressed to the outside.

The backlight 120 is classified into a side type and a direct type according to the position of a light source (not shown) that emits light, and the backlight type is located from one side of the rear side thereof with respect to the liquid crystal panel 110. The light of the emitted light source (not shown) is refracted by a separate light guide plate (not shown) to be incident on the liquid crystal panel 110, and the direct type directly arranges a plurality of light sources (not shown) on the back of the liquid crystal panel 110. Make light incident

The present invention can use either of them.

In this case, a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp may be used as a light source (not shown). Alternatively, in addition to such a fluorescent lamp, a light emitting diode lamp may be used as a lamp.

3 is a cross-sectional view schematically illustrating a cross section of the first substrate of FIG. 2.

As shown, the gate electrode 211, the gate electrode 211 and the gate wiring (FIG. 2) extending from the gate wiring 221 and the gate wiring 221 of FIG. 2 on the first substrate 112. A thin film transistor including a gate insulating film 213 formed on an upper portion of the gate insulating film 213, a semiconductor layer 215 formed on the gate insulating film 213, and source and drain electrodes 217 and 219 spaced apart from the semiconductor layer 215. T) is configured.

In this case, the semiconductor layer 215 is composed of an active layer 215a of pure amorphous silicon and an ohmic contact layer 215b of amorphous silicon including impurities. In this case, the thin film transistor T may be formed of pure and impurity amorphous materials. A bottom gate type made of silicon 215a and 215b is shown as an example, and may be formed as a top gate type including a polysilicon layer as a modification thereof.

A protective layer 216 including a drain contact hole 216a exposing a portion of the drain electrode 219 is formed on the source and drain electrodes 217 and 219, and a drain contact thereof is formed on the protective layer 216. The pixel electrode 222 connected to the drain electrode 219 through the hole 216a is formed.

The first alignment layer 250 that determines the initial alignment direction of the liquid crystal molecules of the liquid crystal layer (105 in FIG. 2) is coated on the pixel electrode 222.

At this time, the pixel electrode 222 of the present invention is a guide groove for guiding the movement direction of the alignment material forming the first alignment layer 250 to a portion connected to the drain electrode 219 through the drain contact hole 216a ( 300, see FIG. 4B).

The guide groove 300 (refer to FIG. 4B) may expose a portion of the edge of the drain contact hole 216a by preventing the pixel electrode 222 from being formed in a portion of the edge of the drain contact hole 216a.

In other words, a partial region of the pixel electrode 222 is formed in which the step C is not generated, and the region of the pixel electrode 222 serves as a path through which the alignment material 250a (see FIG. 4A) can spread.

As a result, in the process of forming the first alignment layer 250 on the first substrate 112, the alignment material 250a (see FIG. 4B) forming the first alignment layer 250 is formed of the pixel electrode 222 and the protective layer ( Due to the step (C) with the 216, it is possible to prevent the problem that does not apply to the inside of the drain contact hole (216a).

In detail, the first substrate 112 may generate a step C having a thickness equal to that of the pixel electrode 222 by the pixel electrode 222 formed on the passivation layer 216.

In particular, such a step C may be generated around the drain contact hole 216a, which is a portion where the pixel electrode 222 is patterned and the drain electrode 219 is in contact with the pixel electrode 222.

A first alignment layer 250 is formed on the pixel electrode 222, where the first alignment layer 250 is coated with an alignment material 250a (see FIG. 4B) and then dried by a firing process. When the alignment material 250a (see FIG. 4B) is applied, the alignment material 250a (see FIG. 4B) is applied onto the substrate 112 using an inkjet coating method, and then the alignment material 250a (FIG. 4B) is applied. The first alignment layer 250 is formed to have a uniform thickness on the substrate 112 through the spreading of the liquid phase.

At this time, in the process of spreading the alignment material 250a (see FIG. 4B) to the entire surface of the substrate 112, the alignment material 250a (FIG. 4B) is formed by the step C between the protective layer 216 and the pixel electrode 222. Evenly spread out.

In particular, the alignment material 250a (see FIG. 4B) is not applied into the drain contact hole 216a.

Therefore, the initial molecular arrangement of the liquid crystal molecules of the liquid crystal layer (105 in FIG. 2) cannot be determined in the region where the contact hole 216a is formed, and light leakage occurs through the region, and the light leakage is particularly applicable to the corresponding pixel region ( When P) implements black, it is observed as a large defect, thereby degrading the screen display quality of the liquid crystal display.

Therefore, in the present invention, the direction in which the alignment material 250a (see FIG. 4B) forming the first alignment layer 250 is connected to a portion of the pixel electrode 222 connected to the drain electrode 219 through the drain contact hole 216a of the pixel electrode 222. By forming a guide groove 300 (see FIG. 4B) for guiding the same, the alignment material 250a (see FIG. 4B) is also applied to the inside of the drain contact hole 216a.

Through this, it is possible to prevent the light leakage from occurring, and to prevent the problem of deterioration of the screen display quality of the liquid crystal display device.

This will be described in more detail with reference to FIGS. 4A to 4B.

4A is a plan view schematically illustrating a connection between a general pixel electrode and a drain electrode, and FIG. 4B is a plan view schematically illustrating a connection between a pixel electrode and a drain electrode according to an exemplary embodiment of the present invention.

5A through 5B are cross-sectional views schematically illustrating cross sections taken along lines A and B of FIGS. 4A and 4B, and FIG. 6 schematically illustrates a connection between a pixel electrode and a drain electrode according to another exemplary embodiment of the present invention. It is a plan view shown by.

As illustrated, the pixel electrode 222 contacts the drain electrode 219 through the drain contact hole 216 exposing the drain electrode 219 of the thin film transistor T.

In this case, the pixel electrode 222 is formed to completely cover the drain contact hole 216a.

In the case of the liquid crystal display, when the alignment material 250a is applied onto the substrate 112 of FIG. 3, the alignment material 250a spreads to the entire surface of the substrate 112 of FIG. 3 by using liquid spreadability. In this case, in the case of a general liquid crystal display device, as illustrated in FIG. 4A, the alignment material 250a is drained by a step (C of FIG. 3) of the pixel electrode 222 formed to cover the drain contact hole 216a. It does not spread into the contact hole 216, but spreads along the edge of the drain contact hole 216a, that is, the edge of the pixel electrode 222 covering the drain contact hole 216a.

In contrast, as illustrated in FIG. 4B, the pixel electrode 222 includes the guide groove 300, so that the alignment material 250a also spreads into the drain contact hole 216a.

Here, the guide groove 300 is an area where the pixel electrode 222 is not formed at a part of the edge of the drain contact hole 216a so that the edge of the drain contact hole 216a is exposed. The area of the guide groove 300 is the pixel electrode 222. Step (C of FIG. 3) does not occur, and the alignment material 250a is spread through the guide groove 300 into the drain contact hole 216a.

That is, as shown in FIG. 5A, referring to a cross-sectional view taken along a line A, which is a region where the guide groove 300 is not formed, the pixel electrode 222 is formed on the passivation layer 216 to form the pixel electrode 222. ) And the passivation layer 216 may generate a step C corresponding to the thickness of the pixel electrode 222.

On the contrary, as shown in FIG. 5B, referring to a cross-sectional view taken along the line B of the region where the guide groove 300 is formed, the pixel electrode 222 exposes the edge of the drain contact hole 216a.

Therefore, the step C is not generated between the pixel electrode 222 and the passivation layer 216 in the region where the guide groove 300 is formed, so that the alignment material 250a is caused by the step C of the pixel electrode 222. ) Is prevented from occurring a problem that is not applied to the drain contact hole (216a).

In this case, the edge of the drain contact hole 216a in which the guide groove 300 is formed is formed to be rounded so that the alignment material 250a more easily spreads into the drain contact hole 216a through the guide groove 300. can do.

Here, at least one guide groove 300 of the pixel electrode 222 is formed at an edge of the pixel electrode 222 corresponding to an edge of the drain contact hole 216a.

That is, referring back to FIG. 4B, if two edges of the pixel electrode 222 and the drain contact hole 216a correspond to each other, the guide groove 300 may correspond to each other of the pixel electrode 222 and the drain contact hole 216a. At least one edge is preferably formed at each edge. As shown in FIG. 6, if the three edges of the pixel electrode 222 and the drain contact hole 216a correspond to each other, the guide groove 300 may be formed with the pixel electrode 222. At least one is preferably formed at each edge of the drain contact hole 216a corresponding to each other.

The width D of the guide groove 300 may be variously changed depending on the spreadability of the liquid phase of the alignment material 250a, and may also be variously changed according to the efficiency of the process. That is, in order to improve the efficiency of the process or lower the spreadability of the liquid phase of the alignment material 250a, the width of the guide groove 300 in order to allow the alignment material 250a to be applied into the drain contact hole 216a more quickly. It is to form D) widely.

The guide groove 300 of the pixel electrode 222 may form a pattern of a mask (not shown) corresponding to the guide groove 300 in the process of patterning the pixel electrode 222, or of the pixel electrode 222. It may be formed by adjusting the amount of light irradiated corresponding to the guide groove (300).

Meanwhile, in the above description, the common electrode (215 in FIG. 2) and the pixel electrode 222 are formed on the first and second substrates 112 and 114 in FIG. 2, respectively, to form a TN mode as an example. However, the present invention is applicable to the IPS mode in which both the pixel electrode 222 and the common electrode (215 in FIG. 2) are formed on the first substrate 112.

As described above, the liquid crystal display of the present invention forms a guide groove 300 exposing a portion of the edge of the drain contact hole 216a at the edge of the pixel electrode 222 corresponding to the drain contact hole 216a. In the process of forming the alignment layer 250 on the substrate 112 through an inkjet coating method, the alignment material 250a may be easily applied into the drain contact hole 216a.

Through this, it is possible to prevent the light leakage from occurring, and to prevent the problem of deterioration of the screen display quality of the liquid crystal display device.

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

211: gate electrode, 216a: drain contact hole, 217: source electrode, 218: data wiring
219: drain electrode, 221: gate wiring, 222: pixel electrode, 250a: alignment material

Claims (8)

A first substrate including a gate wiring, a data wiring, and a thin film transistor;
A protective layer including a contact hole exposing the drain electrode of the thin film transistor;
A pixel electrode formed on the protective layer and including a guide groove which contacts the drain electrode through the contact hole and exposes a part of an edge of the contact hole;
A first alignment layer formed on an entire surface of the first substrate including the pixel electrode;
A second substrate facing the first substrate and having a second alignment layer formed thereon;
A liquid crystal layer formed in the spaced space between the first and second alignment layers;
A common electrode formed on any one selected from the first substrate and the second substrate and forming an electric field with the pixel electrode.
And an alignment material constituting the first alignment layer is guided into the contact hole through the guide groove.
The method of claim 1,
And the guide groove is formed at an edge of the pixel electrode corresponding to an edge of the contact hole.
The method of claim 1,
And an edge of the contact hole is rounded.
The method of claim 1,
The alignment material is a liquid crystal display device is applied on the first substrate through an inkjet coating method.
The method of claim 1,
And a rate at which the alignment material is guided into the contact hole by adjusting the width of the guide groove.
A substrate on which the first wiring is formed;
An insulating material formed on the substrate and including a contact hole exposing the first wiring;
A second wiring formed on the insulating material and including a guide groove contacting the first wiring through the contact hole and exposing a portion of an edge of the contact hole;
A liquid material layer formed on the front surface of the substrate including the second wiring and applied into the contact hole through the guide groove.
Wiring contact structure comprising a.
The method according to claim 6,
And the guide groove is formed at an edge of the second wiring corresponding to an edge of the contact hole.
The method according to claim 6,
And an edge of the contact hole is rounded.

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