JP2001264793A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent sufficiently a short circuit between a metal light shielding layer 31 on the undersurface of the projecting part 3b of a counter substrate 3 and an electrically conductive layer 15 on an array substrate 1 even when an electrically conductive foreign matter enters the clearance between the projecting part 3b where the counter substrate 3 projects outside from a sealing material 2 and an array substrate 1 in a liquid crystal display device manufactured with a patterning process with array substrates of five or less. SOLUTION: An insulating overcoat layer 33 is provided so as to clad the undersurface of the projecting part 3b of the counter substrate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device for performing a matrix display. In particular, the present invention relates to a liquid crystal display device in which a metal light-shielding layer is disposed on a counter substrate, and a conductive layer for contact is disposed on the surface of an image non-display area (frame area) of an array substrate.

[0002]

2. Description of the Related Art In recent years, flat-panel display devices replacing CRT displays have been actively developed. Among them, liquid crystal display devices have attracted particular attention because of their advantages such as light weight, thinness, low power consumption, and low eye fatigue. I am collecting.

[0003] For example, a light-transmitting active-matrix liquid crystal display device in which a switch element is arranged for each display pixel will be described as an example. The active matrix type liquid crystal display device has a configuration in which a liquid crystal layer is held between an array substrate and a counter substrate via an alignment film. The liquid crystal layer is sealed with a sealing material from four sides.

In an array substrate, a plurality of signal lines and scanning lines are arranged in a grid on a transparent insulating substrate such as glass or quartz, and amorphous silicon (hereinafter a-S) is provided at each intersection.
i: H. ) And the like (hereinafter simply referred to as TFT) using a semiconductor thin film. The gate electrode of the TFT is electrically connected to a scanning line, the drain electrode is electrically connected to a signal line, and the source electrode is a transparent conductive material forming a pixel electrode, for example, ITO.
(Indium-Tin-Oxide).

[0005] The opposing substrate has a transparent insulating substrate made of glass or the like, on which a matrix-shaped or striped metal light-shielding layer pattern (black matrix) and an opposing electrode made of ITO are arranged. If a color display is to be realized, a color filter layer is arranged.

Here, usually, on the gate electrode and the scanning line, in order to insulate a semiconductor layer and the like above the gate electrode and the scanning line,
A first gate insulating film made of silicon oxide is provided, and a second gate insulating film made of silicon nitride is further provided. Further, an interlayer insulating film made of silicon nitride is arranged between the transparent conductive material layer and a metal wiring layer such as a signal line.

In reducing the manufacturing cost of such an active matrix liquid crystal display device, there is a problem that the number of steps for manufacturing an array substrate is large and the cost ratio of the array substrate is high.

Therefore, in Japanese Patent Application No. 8-260572, a pixel electrode is arranged on the uppermost layer, and accordingly, a signal line,
After collectively patterning the semiconductor film and the like together with the source and drain electrodes based on the same mask pattern, a contact hole for the source electrode connecting the source electrode and the pixel electrode is formed, and a signal line and a scanning line are formed. It has been proposed to simultaneously form an outer peripheral contact hole for exposing a connection end.

Here, a lead wiring (oblique wiring) extending from the connection pad portion formed on the peripheral edge of the array substrate to the end of the signal line and the scanning line has a redundant wiring structure.
Specifically, the first conductive layer formed simultaneously with the scanning line and the second conductive layer formed simultaneously with the signal line are arranged so as to overlap with each other via an insulating film. The first and second conductive layers are electrically connected to each other at both ends of the oblique wiring by the outer peripheral contact holes.

Specifically, the outer peripheral contact hole includes a first contact hole for exposing the first conductive layer,
A second contact hole for exposing the second conductive layer is provided, and the contact conductive layer is arranged so as to bridge these contact holes. This contact conductive layer is a conductive layer formed simultaneously with the pixel electrode.

However, the liquid crystal display having the above structure has a problem as shown in FIG.

At the outer periphery of the liquid crystal display device, the array substrate 1 protrudes from the opposing substrate 3 to form a shelf-shaped connection region 1a, and a seal is provided between the edge 3a of the opposing substrate 3 and the array substrate 1. Material 2 is arranged. Here, for example, the sealing material 2 is applied on the opposing substrate 3 so that the array substrate 1
It is heated and cured after combining with
It is necessary to provide a certain margin between the position where the sealing material 2 is disposed and the edge 3 a of the counter substrate 3. This is because when the sealing material 2 protrudes from the edge 3 of the substrate, there is a problem such as a decrease in sealing reliability. In addition, due to the physical properties of the sealing material 2, a certain degree of blurring of the application position cannot be avoided. .

Therefore, on the outside of the sealing material 2,
A gap is formed between the array substrate 1 and the opposing substrate 3.

On the other hand, the alignment films 16 and 34 covering the surfaces of the array substrate 1 and the opposing substrate 3 on the liquid crystal 25 side are generally arranged in a region inside the sealing material 2. This is because there are problems such as adhesion and sealing properties between the sealing material 2 and the substrates 1 and 3.

Therefore, the contact conductive layer 15 in the contact hole 18 outside the sealing material at the outer end of the lead wiring 6 is exposed on the surface of the array substrate 1. Then, at the protruding portion 3b of the opposing substrate 3 protruding outside the sealing material 2, the metal light shielding layer 31 is exposed on the surface.

Therefore, in the gap between the array substrate 1 and the counter substrate 3 outside the sealing material 2, the scattered solder particles 5
When such a conductive foreign substance is caught, a short circuit occurs between the wirings 11 and 13 on the array substrate 1 and the counter electrode layer 32 of the counter substrate 3, and a display defect occurs.

If the light-shielding layer (black matrix) on the opposite substrate is formed of a resin layer, no short circuit occurs, but it is necessary to increase the thickness of the black matrix layer, and to make the thickness of the liquid crystal layer uniform. There were problems such as difficulty and many restrictions on the process. Therefore, it is often difficult to use the black matrix as a resin layer.

On the other hand, if the lead-out wiring 6 does not have a redundant wiring structure, there is no need to provide a contact hole at the outer end of the lead-out wiring 6, as shown in FIG. No short circuit occurs. However, as described above, in this case, particularly in a high-definition type liquid crystal display device, disconnection failure of the lead-out wiring 6 due to dust or the like in an exposure process cannot be sufficiently prevented, resulting in a decrease in product yield. .

[0019]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a metal light-shielding layer disposed on a counter substrate and a contact non-display area (frame area) on an array substrate. An object of the present invention is to provide a liquid crystal display device provided with a conductive layer, which can prevent a short circuit caused by conductive dust between the metal light shielding layer and the conductive layer for contact.

[0020]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: an array substrate having a pixel region and an image non-display region surrounding the pixel region; A liquid crystal layer held between them, and a sealing material for sealing the liquid crystal layer from four sides. The array substrate has a first conductive layer including a scanning line, a first conductive layer covering the first conductive layer. An insulating layer, a second conductive layer including a signal line, a second insulating layer covering the second conductive layer, and a third conductive layer including a pixel electrode are arranged in this order. A first contact hole penetrating through the second insulating layer and exposing the first conductive layer; a second contact hole penetrating through the second insulating layer to expose the second conductive layer; and the first and second contact holes And the first conductive layer and the second conductive layer. A contact layer that electrically connects the conductive layers to each other, wherein the contact layer is a conductive layer included in the third conductive layer; in the liquid crystal display device, the opposing substrate protrudes outside the sealing material; The contact layer is exposed on the surface of the array substrate so as to face the protrusion, and the metal light-shielding layer is covered with an insulating coating layer at least at a position corresponding to the contact layer of the protrusion. Features.

According to the above configuration, even when conductive foreign matter enters the gap between the counter substrate and the array substrate outside the sealing material, the metal light-shielding layer at the edge of the counter substrate and the conductive layer on the array substrate Is sufficiently prevented from occurring.

In the liquid crystal display device according to the second aspect, the metal light-shielding layer is covered with an insulating coating layer,
In the pixel region, the same insulating coating layer as an alignment film covering the surface of the array substrate covers the contact layer.

With such a configuration, similarly, the occurrence of a short circuit can be sufficiently prevented. Moreover, the manufacturing process and the manufacturing cost do not increase.

According to a third aspect of the present invention, in the liquid crystal display device, the metal light-shielding layer is covered with an insulating coating layer,
The metal light-shielding layer is omitted in a region corresponding to the contact layer.

With such a configuration, the occurrence of a short circuit can be similarly sufficiently prevented. Moreover, the manufacturing process and the manufacturing cost do not increase.

In the liquid crystal display device according to the fourth aspect, the metal light-shielding layer is covered with an insulating coating layer instead of being covered with an insulating coating layer.
The contact layer is covered with the sealing material.

With such a configuration, similarly, the occurrence of a short circuit can be sufficiently prevented.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 4 of the present invention
Each will be described with reference to FIGS.

FIG. 1 is a schematic sectional perspective view showing an outer peripheral portion on the signal line side of the liquid crystal display device according to the first embodiment, and FIG. 2 is a plan view of a portion corresponding to FIG.

The array substrate 1 and the opposing substrate 3 are combined with each other via the sealing material 2, and the liquid crystal layer 25 is held between them. Then, in a shelf-like connection region 1a where the array substrate 1 protrudes outward from the edge 3a of the counter substrate 3,
A pad portion 19 for supplying a drive signal and drive power to the array substrate 1 and the counter substrate 3 is formed. In the illustrated outer peripheral portion on the signal line side, the signal line 13 is
Is electrically connected to the wiring 11 forming the pad portion 19 via the lead wiring 6 extending from the inside to the outside of the wiring. In addition, the lead wiring 6 is a redundant wiring of an extended part (leader lower wiring) 11a from the pad part wiring and an extended part 13a from the signal line, and these upper and lower wirings 11a, 13a are provided.
Are contact hole portions 17 at the inner end of the lead-out wiring 6,
In addition, conduction is provided by the contact hole portion 18 at the outer end of the lead wiring 6.

The opposing substrate 3 protrudes out of the sealing material 2 in a shelf shape to form a protruding portion 3b, and an external contact is formed on the array substrate 1 so as to face the lower surface of the protruding portion 3b. The hole part 18 is arranged. In the place of the contact hole portion 18, the lead-out wiring 6
(Indium Ti) connecting the upper and lower wirings 11a and 13a of
n Oxide) or the like is exposed.

Here, an insulating overcoat layer 33 is applied to the entire lower surface of the counter substrate 3, and the metal light shielding layer 31 on the lower surface of the protruding portion 3 b is also covered by the overcoat layer 33. . Due to the presence of the overcoat layer 33, the protrusion 3
The short circuit between the metal light shielding layer 31 on the bottom surface b and the contact conductive layer 15 in the contact hole 18 of the array substrate 1 is prevented.

Hereinafter, the manufacturing process of the liquid crystal display device will be described.

First, roughly five photo-etching steps (PEP: Photo Etching Pr
oces).

(1) First PEP: After depositing a metal thin film (first conductive layer) such as molybdenum-tungsten alloy (Mo-W), patterning is performed by patterning, scanning line, pad portion wiring 11, and lead-out lower wiring. 11a is formed.

(2) Second PEP: First, a gate insulating film 12 for covering a scanning line and the like, a semiconductor layer for forming a TFT active layer, and an insulating layer for forming a channel protection film of the TFT include:
The layers are successively deposited in this order. Then, an island-shaped channel protective film is formed by patterning.

(3) Third PEP: After depositing the upper metal layer (second conductive layer) for forming the source / drain electrodes of the TFT, the upper lead wiring 13a and the signal line 13,
The upper metal layer and the semiconductor layer are collectively patterned using one mask pattern. At this time, contact hole openings penetrating the upper metal layer are formed at the contact hole portions 17 and 18.

(4) Fourth PEP: After the interlayer insulating film 14 covering the pattern of the upper metal layer is deposited, the interlayer insulating film 14 is formed by patterning at the locations of the source electrode of the TFT and the locations of the contact holes 17 and 18. The film 14 is removed. At the same time, the gate insulating film 12 is removed at the contact hole opening and the pad 19. Thus, the contact hole portion 1
At the locations 7 and 18, a first contact hole exposing the upper surface of the lead line lower layer wiring 11a and a second contact hole exposing the upper surface of the lead line upper layer wiring 13a are formed.

(5) Fifth PEP: After a transparent conductive layer such as an ITO film is deposited, a pixel electrode is formed by patterning. At the same time, contact hole portions 17 and 1
8, the upper surface (first contact hole) of the lead line lower layer wiring 11a and the lead line upper layer wiring 13
An island-shaped conductive layer for contact 15 covering the upper surface (a second contact hole) is disposed.

On the other hand, the counter substrate 3 is prepared as follows. First, a metal light shielding layer 31 is formed on a glass substrate by patterning after depositing a metal layer such as chromium (Cr). Next, a counter electrode layer made of a transparent conductive material such as ITO is formed in a region corresponding to the inside of the sealing material 2.
Then, an insulating overcoat layer 33 is applied to the entire surface.

After forming the alignment films 16 and 34 in the region inside the sealing material 3,
The liquid crystal layer 25 is injected through the sealing material 2 and injected.

According to this embodiment, the array substrate 1 is formed only by five photo-etching steps,
Is redundantly structured, and a short circuit between the wiring on the array substrate 1 and the counter electrode layer 32 on the counter substrate 3 is reliably prevented. In addition, since the additional step is only the step of applying the overcoat layer 33 to the counter substrate 3, there is almost no increase in manufacturing costs and steps.

The overcoat layer 33 may be applied and formed only on the peripheral portion of the counter substrate 3 by an appropriate coating device.

FIG. 3 is a sectional perspective view schematically showing an outer peripheral portion on the signal line side of the liquid crystal display device according to the second embodiment.

In this embodiment, the overcoat layer 3 is formed on the opposing substrate 3 in the same configuration as the first embodiment.
3 is provided instead of the outer contact hole 1
The insulating film 4 is arranged so as to cover 8. The insulating film 4 is made of the same polyimide as the alignment film 16 and is formed simultaneously with the alignment film 16. Therefore, even if the insulating film 4 is provided, there is almost no increase in working steps and manufacturing costs.

In the illustrated example, the alignment film 16 and the insulating film are
They are arranged separately with a blanking area near the sealing material 2 interposed therebetween. However, depending on the selection of the sealing material 2, the orientation film 16
And the insulating film may be continuous, that is, the entire surface including the region of the sealing material 2 may be covered with the polyimide film.

In some cases, the insulating film 4 may be provided in a step separate from the step of forming the alignment film 16.

FIG. 4 is a sectional perspective view schematically showing an outer peripheral portion on the signal line side of the liquid crystal display device according to the third embodiment.

In this embodiment, the overcoat layer 3 is formed on the opposing substrate 3 in the same structure as the first embodiment.
3 is provided, the protrusion 3b of the counter substrate 3 is provided.
A ring-shaped cut-out portion 31a is provided in the metal light-shielding layer 31 on the lower surface so as to correspond to a portion surrounding the outer contact hole portion 18 on the array substrate 1. That is, the island-shaped metal light-shielding layer 31b right above the contact hole 18 is
The other part is separated from the metal light shielding layer 31c.

In the illustrated example, the metal light-shielding layer 31 is omitted in a rectangular ring-shaped region of the contact hole 18 that is sufficiently larger than the contact conductive layer 15. Thereby, even if a conductive foreign substance such as a solder ball is sandwiched between the contact hole portion 18 and the protruding portion 3b,
There is no conduction between the conductive layer 15 for contact and the metal light shielding layer 31 c continuous inside the sealant 2, and therefore, the wirings 11 and 13 of the array substrate 1 and the counter electrode layer 32
There is no short circuit between them.

Further, the cutout portion 31a is provided with the sealing material 2
Is performed at the same time as the step of patterning the metal light-shielding layer 31 into a matrix or a stripe in the pixel region inside the pixel region, so that there is no increase in the number of steps and no increase in manufacturing cost or work steps. By providing the cutout portion 31a in the metal light-shielding layer 31, light may leak slightly from this portion.
Since the area ratio of a can be made sufficiently small, light leakage does not pose a problem.

In this embodiment, the ring-shaped punched portion 31 is used.
By providing a, the metal light shielding layer 31 was divided,
For example, a slit-shaped cutout extending along the seal material 2 may be provided in the region of the seal material 2. In some cases, the metal light shielding layer 31 can be omitted in the entire region corresponding to the contact hole portion 18.

FIG. 5 is a sectional perspective view schematically showing an outer peripheral portion on the signal line side of the liquid crystal display device according to the fourth embodiment.

In this embodiment, the overcoat layer 3 is formed on the opposing substrate 3 in the same configuration as the first embodiment.
3 is provided instead of the outer contact hole 1
8 are arranged in the sealing material 2 region. That is,
The contact conductive layer 15 in the contact hole 18 is completely covered with the sealing material 2.

According to this embodiment, it is necessary to reduce the arrangement width of the lead-out wiring 6 or to increase the width of the peripheral image non-display area (frame area). However, if any of these has a margin in design, it is advantageous since a short circuit can be surely prevented without increasing the number of steps.

In this embodiment, depending on the case, the outer contact hole portion 18 can be arranged inside the sealing material 2.

[0057]

According to the present invention, even when conductive foreign matter enters the gap between the opposing substrate and the array substrate outside the seal material, the metal light-shielding layer at the edge of the opposing substrate and the conductive layer on the array substrate are not affected. The occurrence of short circuit between them is sufficiently prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional perspective view schematically illustrating an outer peripheral portion on a signal line side of a liquid crystal display device according to a first embodiment.

FIG. 2 is a plan view of a portion corresponding to FIG.

FIG. 3 is a cross-sectional perspective view schematically illustrating an outer peripheral portion on a signal line side of a liquid crystal display device according to a second embodiment.

FIG. 4 is a cross-sectional perspective view schematically illustrating an outer peripheral portion on a signal line side of a liquid crystal display device according to a third embodiment.

FIG. 5 is a sectional perspective view schematically showing an outer peripheral portion on a signal line side of a liquid crystal display device according to a fourth embodiment.

FIG. 6 is a cross-sectional perspective view schematically showing an outer peripheral portion on a signal line side of a liquid crystal display device according to a conventional technique.

FIG. 7 is a cross-sectional perspective view schematically illustrating an outer peripheral portion on a signal line side of a liquid crystal display device according to another related art.

[Explanation of symbols]

Reference Signs List 1 array board 1a shelf-shaped connection area on the periphery of array board 11 pad wiring 11a extension from pad wiring forming lower layer wiring of lead line (diagonal line) 13 signal line 13a upper layer of lead line (diagonal line) Extending portion from signal line forming wiring 15 Conductive layer for conducting upper and lower wiring in contact hole portion 18 Contact hole portion at outer end of lead wire 2 Seal material 25 Liquid crystal layer 3 Opposite substrate 3b Outer seal material of opposing substrate Protruding part 31 Metal light shielding layer 33 Insulating overcoat layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA48 GA49 GA50 GA51 GA57 GA60 JA24 JA48 JB51 MA14 MA15 MA16 MA18 MA19 MA20 MA32 MA35 NA16 NA25 PA02 PA03 PA04 5C094 AA42 AA43 AA48 BA03 BA43 CA19 DA12 DA15 DB03 EA04 EA05 EA07 EA07 EC02 ED15 FA01 FA02 FB01 FB02 FB12 FB15 GB01

Claims (8)

[Claims] An array substrate on which a pixel region and an image non-display region surrounding the pixel region are formed; a counter substrate on which a pattern of a metal light shielding layer is formed; a liquid crystal layer held therebetween;
A sealing material for sealing the liquid crystal layer from four sides; a first conductive layer including a scanning line; a first insulating layer covering the first conductive layer; and a second conductive layer including a signal line. ,
A second insulating layer covering the second conductive layer, and a third insulating layer including a pixel electrode.
A conductive layer is arranged in this order, and in the image non-display area, a first contact hole that penetrates the first and second insulating layers to expose the first conductive layer, and a second contact hole that penetrates the second insulating layer. A second contact hole for exposing the conductive layer, and a region covering the first and second contact holes;
A contact layer that electrically connects the conductive layers to each other, wherein the contact layer is a conductive layer included in the third conductive layer. In the liquid crystal display device, the opposing substrate protrudes outside the sealing material. The contact layer is exposed on the surface of the array substrate so as to face the protrusion, and the metal light-shielding layer is covered with an insulating coating layer at least at a position corresponding to the contact layer of the protrusion. Characteristic liquid crystal display device. 2. An array substrate in which a pixel region and an image non-display region surrounding the pixel region are formed, a counter substrate in which a pattern of a metal light shielding layer is formed, and a liquid crystal layer held therebetween.
A sealing material for sealing the liquid crystal layer from four sides; a first conductive layer including a scanning line; a first insulating layer covering the first conductive layer; and a second conductive layer including a signal line. ,
A second insulating layer covering the second conductive layer, and a third insulating layer including a pixel electrode.
A conductive layer is arranged in this order, and in the image non-display area, a first contact hole that penetrates the first and second insulating layers to expose the first conductive layer, and a second contact hole that penetrates the second insulating layer. A second contact hole for exposing the conductive layer, and a region covering the first and second contact holes;
A contact layer for electrically connecting the conductive layers to each other, wherein the contact layer is a conductive layer included in the third conductive layer, wherein the opposing substrate protrudes outside the sealing material; The contact layer is exposed on the surface of the array substrate so as to face the portion, and the same insulating coating layer as the alignment film covering the surface of the array substrate in the pixel region covers the contact layer. Liquid crystal display device. 3. An array substrate on which a pixel region and an image non-display region surrounding the pixel region are formed, a counter substrate on which a pattern of a metal light shielding layer is formed, and a liquid crystal layer held therebetween.
A sealing material for sealing the liquid crystal layer from four sides; a first conductive layer including a scanning line; a first insulating layer covering the first conductive layer; and a second conductive layer including a signal line. ,
A second insulating layer covering the second conductive layer, and a third insulating layer including a pixel electrode.
A conductive layer is arranged in this order, and in the image non-display area, a first contact hole that penetrates the first and second insulating layers to expose the first conductive layer, and a second contact hole that penetrates the second insulating layer. A second contact hole for exposing the conductive layer, and a region covering the first and second contact holes;
A contact layer for electrically connecting the conductive layers to each other, wherein the contact layer is a conductive layer included in the third conductive layer, wherein the opposing substrate protrudes outside the sealing material; The contact layer is exposed on the surface of the array substrate so as to face the portion, and the metal light-shielding layer includes a region inside the sealing material and a region in the protruding portion and facing the contact layer. A liquid crystal display device which is separated from each other or omitted in a region facing the contact layer. 4. An array substrate on which a pixel region and an image non-display region surrounding the pixel region are formed, a counter substrate on which a pattern of a metal light shielding layer is formed, and a liquid crystal layer held therebetween.
A sealing material for sealing the liquid crystal layer from four sides; a first conductive layer including a scanning line; a first insulating layer covering the first conductive layer; and a second conductive layer including a signal line. ,
A second insulating layer covering the second conductive layer, and a third insulating layer including a pixel electrode.
A conductive layer is arranged in this order, and in the image non-display area, a first contact hole that penetrates the first and second insulating layers to expose the first conductive layer, and a second contact hole that penetrates the second insulating layer. A second contact hole for exposing the conductive layer, and a region covering the first and second contact holes;
A contact layer that electrically connects the conductive layers to each other, and wherein the contact layer is a conductive layer included in the third conductive layer, wherein the contact layer is covered with the sealing material. Characteristic liquid crystal display device. 5. The array substrate includes a thin film transistor as a switching element for each pixel, the thin film transistor being a part of the scanning line or a gate electrode formed of an extended portion thereof, and the thin film transistor being disposed on the gate electrode. (1) a semiconductor active layer disposed via an insulating film; and a source electrode and a drain electrode included in the second conductive layer and electrically connected to the semiconductor active layer. A patterning step of forming a pattern of one conductive layer; an active semiconductor film of the thin film transistor;
A patterning step of simultaneously forming a pattern of a conductive layer under one photomask; a patterning step of simultaneously forming a source contact hole exposing an upper surface of the source electrode; and the second contact hole; The liquid crystal display device according to any one of claims 1 to 4, wherein the liquid crystal display device is manufactured by a manufacturing process including a patterning process of forming an electrode and the contact layer. 6. The source contact hole and the second contact hole.
5. The liquid crystal display device according to claim 1, wherein said first contact hole is formed simultaneously in a patterning step of forming a contact hole. 7. A wiring belonging to the first conductive layer and a wiring belonging to the second conductive layer are overlapped in a region from one end of the signal line or the scanning line to the first and second contact holes. The liquid crystal display device according to any one of claims 1 to 4, wherein the liquid crystal display device is arranged to form a redundant wiring. 8. The second contact hole is formed in a region surrounding the first contact hole from four sides, and an outer edge of the first contact hole is directly connected to a bottom surface of the second contact hole. The liquid crystal display device according to claim 1, wherein: