JP2001092378A - Active matrix substrate - Google Patents

Abstract

(57) [Summary] [Problem] To improve the display quality with a high aperture ratio.
An active matrix substrate suitably used for a liquid crystal display device is provided. SOLUTION: A plurality of scanning wirings 2 are formed on an insulating substrate 1 having a light transmitting property. A plurality of signal wirings 8 are arranged so as to intersect with the scanning wirings 2. Switching elements 18 each composed of a thin film transistor are arranged at intersections of the scanning lines 2 and the signal lines 8. The pixel electrodes 13 connected to the switching elements 18 are provided.
A shield electrode 22 maintained at a predetermined voltage is provided via the gate insulating layer 5 at a position opposite to the pixel electrode 13 with the signal wiring 8 interposed therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an active matrix substrate used for a liquid crystal display device and the like.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display device, a so-called active matrix substrate in which a thin film transistor (TFT) made of amorphous Si is formed as a switching element on a substrate together with a plurality of gate lines and data lines crossing each other. It is known to use FIG. 7 shows a configuration diagram of a conventional active matrix substrate. FIG. 7A is a schematic plan view of one pixel portion of the active matrix substrate, and FIG. 7B is a cross-sectional view of a main part of the active matrix substrate taken along the line ABC shown in the schematic plan view. is there.

[0003] Such an active matrix substrate will be described below based on a manufacturing method thereof. First, a scanning wiring 52, a gate electrode 53 extending from the scanning wiring 52, and an auxiliary capacitance wiring 54 are formed on a substrate 51 made of glass, plastic, or the like having transparency, that is, light transmission and electrical insulation. I do.

Next, a gate insulating layer 55, amorphous S
After laminating the i-layer 56 and the n + amorphous Si layer 57 serving as source and drain electrodes, the amorphous Si layer 56 and the n + amorphous Si layer 57 are patterned in an island shape to form an island pattern on the gate electrode 53.

Next, a transparent metal layer made of ITO or the like serving as the pixel electrode 70 and a metal layer serving as the signal wiring 58 are
Each is laminated on the island-shaped n + amorphous Si layer 57 and the gate insulating layer 55 so as to be the same layer, and the metal layer and the transparent metal layer are patterned to form the signal wiring 58 and the pixel electrode 70, respectively. I do. The metal layer serving as the signal wiring 58 may be formed of a metal such as Ta, Cr, Mo, or Al, or a plurality of these metals may be stacked.

Next, of the island-shaped amorphous Si layer 56 and the n + amorphous Si layer 57, the n + amorphous Si layer 57 which is a portion between the signal wiring 58 and the drain electrode 71 is removed by etching, and the source electrode and the drain electrode are removed. The switching element 68 is formed by dividing the electrode into electrodes. After the formation of the switching element 68, the TFT protection layer 60 made of SiNx or the like is formed, and the active matrix substrate is completed.

An alignment film 6 is formed on the active matrix substrate.
4, a color filter 66, a light shielding film 69, and a counter substrate 67 on which a transparent metal layer serving as a counter electrode 65 is laminated with a predetermined gap, and a liquid crystal layer 82 is filled in the gap to form a desired liquid crystal display. The device is completed.

In the case of the above active matrix substrate,
Since the pixel electrode 70 and the signal wiring 58 are on the same plane, the pixel electrode 70 and the signal wiring 58 are spaced apart from each other by a predetermined distance as shown in a cross-sectional view of a main part indicated by line BC. Is formed.

Therefore, the electric field from the pixel electrode 70 is not applied to the liquid crystal layer 82 between the pixel electrode 70 and the signal wiring 58,
Therefore, in order to suppress a decrease in contrast due to light leakage, this portion needs to be shielded by the light shielding film 69. Therefore, this structure has a disadvantage that the aperture ratio is reduced.

In order to avoid such a drawback, for example, as shown in FIG. 8, the pixel electrode 63 is formed via an interlayer insulating layer 61 with the signal wiring 58, and the pixel electrode 63 is connected to the signal wiring 5 as shown in FIG.
An active matrix substrate having a structure in which a high aperture ratio is formed by omitting the light-shielding region between the pixel electrodes 63 facing the signal wiring 58 by forming the same so as to overlap on the wiring 8 has been devised. FIG. 8A is a schematic plan view of one pixel portion of another conventional active matrix substrate, and FIG. 8B is a cross-sectional view of a principal part of the active matrix substrate taken along line ABC.

With respect to the active matrix substrate shown in FIG. 8, only the differences from the active matrix substrate shown in FIG. 7 will be described below based on the manufacturing method.

First, after forming the above-described protective layer 60 of TFT made of SiNx or the like, after forming a pattern by a photo process, the protective layer 60 is etched with an etching solution made of HF or the like.
Then, a contact hole 60a for connection with the pixel electrode 63 is formed on the auxiliary capacitance wiring 54 by etching.

Next, a photosensitive organic resin-based interlayer insulating layer 61 made of acrylic or the like is applied by a spin coating method.
A contact hole 62 is formed in the exposure step. The pixel electrode 63 is formed via the contact hole 62, and the active matrix substrate is completed. An alignment film 64 is formed on this active matrix substrate, and a color filter 66 is formed.
A counter substrate 67 on which a transparent metal layer serving as a counter electrode 65 is laminated is attached with a predetermined gap, and the gap is filled with a liquid crystal layer 82 to complete a desired liquid crystal display device.

[0014]

However, the above is a method of manufacturing an active matrix substrate for realizing a high aperture ratio. In such a structure, in order to prevent light from leaking, the pixel electrode 63 is driven by a signal. Since it is formed so as to cover the wiring 58, there is a problem that the capacitance between the pixel electrode 63 and the signal wiring 58 is increased.

FIG. 9 shows an equivalent circuit of one pixel portion on the active matrix substrate. Here, Clc is the capacitance between the pixel electrode 63 and the counter electrode 65 with the liquid crystal layer 82 interposed therebetween,
cs is an auxiliary capacitance between the pixel electrode 63 and the auxiliary capacitance line 64;
sd is the capacitance between the pixel electrode 63 and the signal wiring 58, and Cgd is the capacitance between the pixel electrode 63 and the scanning wiring 52.

As described above, since the pixel electrode 63 has a parasitic resistance other than the pixel capacitance and the auxiliary capacitance, the potential of the pixel electrode 63 fluctuates when the voltage of the signal wiring 58 or the scanning wiring 52 changes.

Normally, an AC electric field is applied to the liquid crystal layer 82 in order to prevent the liquid crystal layer 82 from being electrolyzed and deteriorated. Therefore, a voltage having a different polarity is applied to the signal wiring 58 every time one line or one screen is scanned.

At this time, the voltage fluctuation of the signal wiring 58 is ΔVs
Then, the pixel electrode 63 due to the voltage change of the signal wiring 58
The voltage fluctuation of △ VIc = △ Vs * Csd / (Clc + Ccs +
Csd).

In particular, recently, a liquid crystal display device (liquid crystal display) having a high aperture ratio and a high resolution has become essential. In an active matrix substrate used in such a liquid crystal display device, the liquid crystal layer 82 is formed by downsizing pixels. Is required to have a small opening (Clc) and a high aperture ratio. Therefore, it is necessary to reduce the auxiliary capacitance (Ccs) which causes a decrease in the opening ratio.

In such a liquid crystal display device, in particular, the fluctuation of the pixel voltage is a serious problem. For example, the display pattern has a so-called crosstalk around the signal pattern 58 or the scanning pattern 52 along the signal wiring 58 or the scanning wiring 52, which causes a so-called crosstalk. Is degraded.

From the above equation, in order to reduce the voltage fluctuation of the pixel electrode 63, Ccs must be increased or Csd
Needs to be smaller. However, as described above, increasing the auxiliary capacitance decreases the aperture ratio, which is difficult to realize. Therefore, there is a problem that it is necessary to reduce Csd by some method.

Therefore, several methods have conventionally been proposed for reducing the capacitance between the pixel electrode and the signal wiring.

First, in an active matrix substrate having a structure in which the pixel electrode 70 is formed on the same layer as the signal wiring 58, as shown in, for example, JP-A-4-349430, FIG. By arranging a shield electrode 72 as shown in FIG. 10B between the signal wiring 58 and the pixel electrode 70 or below the signal wiring 58 and blocking the electric field between the pixel electrode 70 and the signal wiring 58, A configuration for reducing the capacity between the two has been proposed.

On the other hand, in an active matrix substrate having a structure in which the pixel electrode 63 is also formed on the signal wiring 58 with the interlayer insulating layer 61 interposed therebetween, for example, as shown in FIG. A configuration has been proposed in which the capacitance is formed between the pixel electrodes 63 to block the electric field between the pixel electrode 63 and the signal wiring 58 to reduce the capacitance between the two (see JP-A-5-273593).

However, in the configuration of the above publication, in order to form such a structure, it is necessary to form the interlayer insulating layer 61 in a two-layer structure and to form the shield electrode 72 between the layers. Disadvantage.

[0026]

Means for Solving the Problems The inventors of the present invention provided a shield electrode (electric field shield electrode) between a pixel electrode and a signal wiring in order to reduce the capacitance between the pixel electrode and the signal wiring as conventionally seen. It has been found that the capacitance between the pixel electrode and the shield wiring can be reduced by forming the shield electrode on the opposite side of the pixel electrode with respect to the signal wiring instead of forming the signal wiring, and completed the present invention.

In order to solve the above problems, the active matrix substrate of the present invention is arranged so that a plurality of scanning lines formed on a light-transmitting insulating substrate and each of the scanning lines intersect. A plurality of signal wirings, a switching element formed of a thin film transistor disposed at an intersection of the scanning wiring and the signal wiring, a pixel electrode connected to the switching element, and a signal wiring provided via an insulating layer. And an electric field shielding electrode maintained at a predetermined voltage, wherein the electric field shielding electrode is provided at a position opposite to the pixel electrode with the signal wiring interposed therebetween.

According to the above configuration, even if the pixel electrode is formed on the signal wiring and the aperture ratio of the pixel electrode is improved, the capacitance between the pixel electrode and the signal wiring is reduced as in the related art. Therefore, instead of forming an electric field shielding electrode (shield electrode) between the pixel electrode and the signal wiring, the electric field shielding electrode is formed on the opposite side of the pixel electrode with the signal wiring therebetween, so that the pixel electrode and the signal wiring are formed. Can be reduced.

Thus, in the above configuration, the electric field shielding electrode is formed, for example, in the same layer as the scanning wiring without lowering the aperture ratio of the pixel electrode. The capacitance between the pixel electrode and the signal wiring can be reduced without any increase in the number of manufacturing steps.

Further, in the above configuration, the electric field shielding electrode is sandwiched by the signal wiring formed along each pixel electrode.
That is, since it is formed along the signal wiring, it can be used as a light shield between adjacent pixel electrodes. Accordingly, in the above configuration, it is not necessary to overlap the signal wiring and the pixel electrode. In other words, even if the width of the signal wiring as the light shield is set to be smaller than the distance between the adjacent pixel electrodes, the signal wiring and the pixel electrode become adjacent to each other. Light can be shielded between the corresponding pixel electrodes.

Thus, in the above configuration, the width of the signal wiring can be set small while preventing light from leaking between adjacent pixel electrodes, and the capacitance between the pixel electrode and the signal wiring is further reduced. Thus, a liquid crystal display device having a high aperture ratio and a high display quality can be realized without any change or addition of a manufacturing process.

In the above structure, an interlayer insulating layer may be formed between the pixel electrode and the scanning line and the signal line. With the above configuration, a liquid crystal display device having a high aperture ratio and a high display quality can be obtained more reliably.

In the above configuration, the electric field shielding electrode may be formed to extend from the scanning wiring. According to the above configuration, a liquid crystal display device having a high aperture ratio and a high display quality can be realized without any change or addition of a manufacturing process.

In the above configuration, a capacitance holding line for holding the capacitance of the pixel electrode may be provided between the scanning lines, and the electric field shielding electrode may be formed to extend from the capacitance holding line. According to the above configuration, since the electric field shielding electrode is formed to extend from the capacitance holding wiring, a liquid crystal display device having a high aperture ratio and a high display quality can be realized without changing or adding any manufacturing process. be able to.

In the above configuration, the width of the electric field shielding electrode is
It is preferable that the pixel electrode is formed so as to be larger than the interval between the adjacent pixel electrodes and larger than the width of the signal wiring. According to the above configuration, since the width of the signal wiring can be set small, the capacitance between the pixel electrode and the signal wiring can be reduced, and a liquid crystal display device with a high aperture ratio and high display quality can be obtained more reliably. Can be

In the above configuration, the electric field shielding electrode may be formed at a position facing the signal wiring. According to the above configuration, light shielding between adjacent pixel electrodes can be more reliably performed by the electric field shielding electrode, so that a liquid crystal display device having a high aperture ratio and a high display quality can be obtained more reliably.

In the above configuration, the electric field shielding electrode may be formed so as to be displaced in a width direction of the signal wiring at a position facing the signal wiring. According to the above configuration, since the light shielding between the adjacent pixel electrodes by the electric field shielding electrode can be set in a wider range, the width of the signal wiring can be set smaller, a high aperture ratio, and a high display quality liquid crystal. A display device can be obtained more reliably.

[0038]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

(Embodiment 1) FIG. 1 is a schematic configuration diagram of an active matrix substrate according to Embodiment 1, and FIG. 1A is a schematic plan view of one pixel portion of the active matrix substrate. FIG. 2B is a cross-sectional view of a principal part of the active matrix substrate, which is indicated by line ABC.

The active matrix substrate is a substrate 1
A plurality of scanning wirings 2, a plurality of signal wirings 8, each switching element 18, and each pixel electrode 1 in a matrix
3 and a shield electrode (electric field shield electrode) 22.

The substrate 1 is made of glass, plastic, or the like, which is transparent, that is, has optical transparency and electrical insulation. The scanning lines 2 are provided in parallel with each other. The signal wirings 8 are arranged so as to cross each of the scanning wirings 2 so as to be orthogonal to each other, and are formed in parallel with each other. The switching element 18 is formed of a thin film transistor disposed at each intersection of the scanning wiring 2 and the signal wiring 8. The pixel electrodes 13 are made of a substantially rectangular conductor having a light-transmitting property, and are arranged in a matrix, that is, in a grid pattern connected to the switching elements 18.

The shield electrode 22 is maintained at a predetermined voltage, and is opposite to the pixel electrode 13 with the signal wiring 8 interposed therebetween with the signal wiring 8 interposed therebetween through the gate insulating layer 5. Side positions.

The following is a description of such an active matrix substrate based on its manufacturing method. First, a scanning line 2, a gate electrode 3 extending from the scanning line 2, and an auxiliary capacitance line 4 are formed in the same layer on a substrate 1. At this time, the shield electrode 2 extends from the auxiliary capacitance wiring 4 at the same time, that is, in the same layer.
2 is formed below the signal wiring 8 described later, that is, between the signal wiring 8 and the substrate 1 via the gate insulating layer 5.

Next, after a gate insulating layer 5 made of SiNx or the like, an amorphous Si layer 6, and an n + amorphous Si layer 7 serving as a source electrode and a drain electrode are further laminated sequentially, the amorphous Si layer 6 and the n + amorphous Si layer 7 are formed. By patterning, an island pattern is formed on the gate electrode 3.

Next, the connection electrode 9 with the pixel electrode 13 and the metal layer serving as the signal wiring 8 are laminated and patterned. This metal layer may be made of a metal such as Ta, Cr, Mo, Al, and ITO, or a plurality of these metals may be laminated.

Next, of the island-shaped amorphous Si layer 6 and the n + amorphous Si layer 7, the n + amorphous Si layer 7 at a portion between the signal wiring 8 and the connection electrode 9 is removed by etching, and the n + amorphous Si layer 7 is removed. Then, the switching element 18 is formed by forming a source electrode and a drain electrode by division.

After the formation of the switching element 18, SiNx
A TFT protective layer 10 made of, for example, is further formed on the substrate 1, and after a pattern is formed by a photo process,
By etching the protective layer 10 with an etching solution made of HF or the like, a contact hole 10a for connection with the pixel electrode 13 described later is formed so as to expose the connection electrode 9 on the auxiliary capacitance line 4.

Next, a photosensitive organic resin such as an acrylic resin is applied on the substrate 1 by a spin coating method to form an organic resin layer. An interlayer insulating layer 11 from above and a contact hole 12 with respect to the interlayer insulating layer 11.
Is formed on the contact hole 10a.

Subsequently, a pixel electrode layer is formed on the interlayer insulating layer 11, and the pixel electrode 13 is formed on the interlayer insulating layer 11 from the pixel electrode layer by etching or the like. Then, the connection electrode 9 and the pixel electrode 13 are connected to each other to complete the active matrix substrate.

While an alignment film 14 is formed on each pixel electrode 13 and on the interlayer insulating layer 11 of the active matrix substrate, a counter substrate 17 on which a color filter 16 and a transparent metal layer serving as the counter electrode 15 are laminated is formed. The active matrix substrate and the opposing substrate 1
7 are bonded to each other so as to have a predetermined gap, and the gap is filled with a liquid crystal layer 19 to complete a desired liquid crystal display device.

In the present invention, the pixel electrode 13 is formed of the interlayer insulating layer 1
1 (b) and FIG. 1 (b) show a high aperture ratio active matrix substrate which is formed on the signal wiring 8 via the first electrode 1 and in which the pixel electrode 13 is formed so as to also overlap the signal wiring 8 in order to improve the aperture ratio. As shown in FIG. 2, when forming the scanning wiring 2 or the auxiliary capacitance wiring 4, the shield electrode 22 formed at the same time as extending from the scanning wiring 2 or the auxiliary capacitance wiring 4 is connected to the pixel electrode 13 with the signal wiring 8 interposed therebetween. This is a configuration arranged on the opposite side.

Thus, in the above configuration, the pixel electrode 13
The formation of the electric field 8a between the pixel electrode 13 and the signal wiring 8 can be reduced by providing the shield electrode 22, and the capacitance between the pixel electrode 13 and the signal wiring 8 can be reduced.

Therefore, by applying the structure of the shield electrode 22 to an active matrix substrate in which the pixel electrode 13 and the signal wiring 8 are formed via the interlayer insulating layer 11, a liquid crystal display device using the active matrix substrate In order to suppress the occurrence of display quality deterioration such as shadowing, and to realize a high-quality liquid crystal display device without changing the manufacturing process from the conventional one, that is, by a simple method without additional steps Can be.

An example of the result of the capacitance reduction between the pixel electrode 13 and the signal wiring 8 in the active matrix substrate having such a structure is shown in Table 1 below. However, the distance between the adjacent pixel electrodes 13 is set to 3 μm, the width of the shield electrode 22 and the width of the signal wiring 8 are set to 8 μm, the thickness of the gate insulating layer 5 is 350 nm, the dielectric constant is 6.9, and the interlayer insulating layer 11 is Of 3,000 nm and a dielectric constant of 3.4. Further, as a conventional structure, a structure as shown in FIG. 8 was used in which the shield electrode 22 was omitted in FIG. 1 and other structures were similarly set.

[0055]

[Table 1]

As shown in Table 1 above, the structure according to the first embodiment is different from the conventional structure shown in FIG.
It has been found that the capacitance between the wiring 3 and the signal wiring 8 can be reduced by about 36%.

(Embodiment 2) FIG. 3A shows a case where the structure of the overlapping portion (BC portion) of the shield electrode 22, the signal wiring 8, and the pixel electrode 13 is changed from that of the above-mentioned Embodiment 1. Show. In the first embodiment, the light shielding between the pixel electrodes 13 is performed by arranging the signal wiring 8 so as to overlap between the adjacent pixel electrodes 13. However, in the second embodiment, the shield electrode 22 is also provided. By performing the above light shielding using
The electrode width of the signal wiring 8 is set smaller than the above.

For example, the distance between the pixel electrodes 13 is 3 μm, the width of the signal wiring 8 is 5 μm, and the width of the shield electrode 22 is 8 μm.
When each is set, the width of the signal wiring 8 is 8
As compared with the case of μm, the capacitance between the pixel electrode 13 and the signal wiring 8 can be reduced as shown in Table 2 below. It has been found that in the present structure, the capacitance of the pixel electrode 13 and the signal wiring 8 can be further reduced by about 64% as compared with the conventional structure.

Thus, in the above structure, the capacitance can be further reduced, so that the signal delay in the signal wiring 8 can be further suppressed. Therefore, with the above structure, a liquid crystal display device with higher image quality can be realized without changing the manufacturing process from the conventional one, that is, by a simple method without additional steps.

[0060]

[Table 2]

Conventionally, as shown in FIG. 4A, for example, as shown in FIG. 4A, the pixel electrode 63 is formed so as to partially overlap the signal wiring 58 so that the light 81 incident from the backlight is Leakage (light leakage) outside the region, that is, between adjacent pixel electrodes 13 is prevented.

When the width of the signal line 58 is equal to or smaller than the distance between the pixel electrodes 63 as shown in FIG. 4B, for example, the overlap between the pixel electrode 63 and the signal line 58 is reduced. Although the capacitance between the pixel electrode 63 and the signal wiring 58 can be reduced, light passes through the area other than the pixel electrode 13 depending on the incident angle of the light 81,
As the contrast decreases, the display quality deteriorates.

However, in the present invention, since the shield electrode 22 is formed below the signal wiring 8 as shown in FIGS. 3A and 4C, even when the electrode width of the signal wiring 8 is reduced, the shield electrode 22 is formed. The electrode 22 serves as a light-shielding body, so that light 21 can be prevented from leaking out of the region of the pixel electrode 13.

Therefore, in the above configuration, it is not necessary to particularly form the pixel electrode 13 and the signal wiring 8 so as to overlap each other in order to prevent light leakage, and the capacitance between the pixel electrode 13 and the signal wiring 8 is further increased. Can be reduced. Therefore, with the above configuration, a liquid crystal display device with higher image quality can be configured.

(Embodiment 3) In each of Embodiments 1 and 2, the capacitance between the pixel electrode 13 and the signal wiring 8 is reduced by forming the shield electrode 22 so as to overlap below the signal wiring 8. However, for example, in a large-sized and high-definition display, the capacity between the signal wiring 8 and the shield electrode 22 becomes large, so that a problem of signal delay in the signal wiring 8 arises.

In order to solve this problem, in the third embodiment according to the present invention, as shown in FIG. 3B, the shield electrode 22 is divided in the width direction of the signal wiring 8 and each shield electrode 22 is divided. 22 are displaced in the width direction of the signal wiring 8, respectively, and the overlapping area between the signal wiring 8 and the shield electrode 22 is reduced.
The capacity between them is set to be smaller.

However, also in this structure, in order to prevent light leakage between the adjacent pixel electrodes 13, the signal wiring 8 and the shield electrodes 22 are partially connected at their ends in the width direction. They are arranged so as to overlap each other in their thickness direction. With such a structure, a light-shielding region for preventing the light leakage can be increased while avoiding an increase in capacitance. Therefore, light leakage between the pixel electrodes 13 can be reduced.
Furthermore, it can be prevented more efficiently.

(Embodiment 4) Each of the above embodiments 1 to
3 is an example in which the scanning wiring 2 and the auxiliary capacitance wiring 4 are formed as separate wirings. However, in each of the first to third embodiments, the auxiliary capacitance formed between the connection electrode 9 and the auxiliary capacitance wiring 4 is replaced with the adjacent scanning wiring 2.
By forming it above, the auxiliary capacitance wiring 4 can be omitted,
FIGS. 5 and 6 show examples in which the structure of the shield electrode 22 of the present invention is applied to an active matrix substrate having such a structure.

In each of the first to third embodiments, the shield electrode 2
In the fourth embodiment, the shield electrode 22 is formed so as to extend from the scanning wiring 2, and the auxiliary capacitance is formed using the contact hole 12. Thus, it is formed between the connection electrode 9 a electrically connected to the pixel electrode 13 and the scanning wiring 2.

In the fourth embodiment, as shown in FIG. 5B, the underlayer 4 is provided between the contact hole 12 and the substrate 1.
1 is formed in the shape of an island at a position facing the void of the contact hole 12 from the same material as the above-described auxiliary capacitance wiring 4.

By providing such an underlayer 41, when the contact holes 12 and the contact holes 10a are formed by etching, corrosion, erosion, and diffusion of a chemical to the substrate 1 due to an etching agent are excellent in chemical resistance. The underlayer 41 can surely prevent this.

In the fourth embodiment, as shown in FIGS. 5 and 6, a structure corresponding to the first embodiment in which the shield electrode 22 is formed extending from the auxiliary capacitance line 4 is described. Although an example in which the invention according to the fourth embodiment is applied is described, it is apparent that the invention according to the fourth embodiment can be applied to the structures shown in the second and third embodiments. is there.

Further, the first to third embodiments have been described.
Even when the auxiliary capacitance line 4 is formed separately from the scanning line 2, it is possible that the shield electrode 22 can be formed to extend from the scanning line 2 as shown in the fourth embodiment. it is obvious.

As described above, according to the present invention, the pixel electrode 13 is formed on the signal line 8 via the interlayer insulating layer 11, and
In a high aperture ratio active matrix substrate in which the pixel electrode 13 is also formed on the signal wiring 8 so as not to lower the aperture ratio, the scanning wiring 2 or the auxiliary capacitance wiring 4 is simultaneously formed when the scanning wiring 2 or the auxiliary capacitance wiring 4 is formed. The shield electrode 22 extending from 4 is arranged on the opposite side of the pixel electrode 13 with the signal wiring 8 interposed therebetween.

Thus, in the above configuration, the pixel electrode 1 can be formed without increasing the number of steps in the conventional manufacturing method.
3 and the signal wiring 8 can be reduced by about 30 to 70%. As a result, in the above configuration, when used in a liquid crystal display device, the crosstalk on the display screen, particularly in the vertical direction, can be reduced and the display quality can be improved due to the reduction in the capacitance.

[0076]

According to the present invention, the active matrix substrate
As described above, the plurality of scanning lines formed on the light-transmitting insulating substrate, the plurality of signal lines intersecting with each of the scanning lines, and the intersection of the scanning lines and the signal lines A switching element composed of a thin film transistor arranged in each part, a pixel electrode respectively connected to the switching element, and an electric field shielding electrode which is provided through an insulating layer for the signal wiring and is held at a predetermined voltage. And the electric field shielding electrode is provided at a position opposite to the pixel electrode with the signal wiring interposed therebetween.

Therefore, in the above configuration, even if the pixel electrode is formed also on the signal wiring and the aperture ratio of the pixel electrode is improved, the electric field shielding electrode is located on the opposite side to the pixel electrode with the signal wiring interposed therebetween. Is formed in the same layer as the scanning wiring, for example, the capacitance between the pixel electrode and the signal wiring can be reduced.

Thus, in the above configuration, the pixel electrode can be formed without lowering the aperture ratio of the pixel electrode and without increasing the manufacturing process by forming the electric field shielding electrode in the same layer as the scanning wiring, for example. , And the capacitance between the signal wiring can be reduced.

As a result, in the above configuration, a liquid crystal display device having a high aperture ratio and a high display quality due to the reduction of the capacitance between the pixel electrode and the signal wiring can be realized without any change or addition of the manufacturing process. This has the effect.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory diagrams of an active matrix substrate according to a first embodiment of the present invention, wherein FIG. 1A is a schematic plan view of one pixel portion of the active matrix substrate, and FIG. FIG. 4 is a cross-sectional view of a main part of the active matrix substrate, which is indicated by line ABC in FIG.

FIG. 2 is a cross-sectional view showing a state of an electric field between a pixel electrode and a signal wiring and a structure of a shield electrode in the active matrix substrate.

FIGS. 3A and 3B are cross-sectional views of a main part showing an arrangement of shield electrodes with respect to signal wirings in the active matrix substrate. FIG. 3A is an example, and FIG. 3B is another example.

FIGS. 4A and 4B are explanatory diagrams showing states of light leakage between pixel electrodes in various structures in the active matrix substrate, wherein FIG. 4A shows a conventional example and FIG. 4B shows another conventional example. An example is shown, and (c) shows the present invention.

5A and 5B are explanatory diagrams of an active matrix substrate according to a fourth embodiment of the present invention, wherein FIG. 5A is a schematic plan view of one pixel portion of the active matrix substrate, and FIG. FIG. 4 is a cross-sectional view of a main part of the active matrix substrate, which is indicated by line ABC in FIG.

FIG. 6 is a cross-sectional view of a main part of the active matrix substrate, which is indicated by a line D-E shown in FIG. 5A.

7A and 7B are explanatory views of a conventional active matrix substrate, in which FIG. 7A is a schematic plan view of one pixel portion of the active matrix substrate, and FIG. 7B is a diagram showing ABC of FIG.
FIG. 3 is a cross-sectional view of a main part of the active matrix substrate indicated by a line.

FIGS. 8A and 8B are explanatory views of another conventional active matrix substrate, in which FIG. 8A is a schematic plan view of one pixel portion of the active matrix substrate, and FIG.
FIG. 3 is a cross-sectional view of a main part of the active matrix substrate, which is indicated by a line C.

FIG. 9 is an explanatory diagram showing an equivalent circuit per pixel in the active matrix substrate.

10A and 10B are cross-sectional views of main parts showing an arrangement of shield electrodes with respect to signal wirings in the active matrix substrate shown in FIG. 7; FIG. 10A is an example of the arrangement;
(B) is another example of the above arrangement.

11 is a cross-sectional view of a principal part showing the arrangement of shield electrodes with respect to signal wirings in the active matrix substrate shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Scanning wiring 5 Gate insulating layer 8 Signal wiring 13 Pixel electrode 18 Switching element 22 Shield electrode (electric field shielding electrode)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat 参考 (Reference) H01L 21/336 (72) Inventor Atsushi Ban 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 2H092 JA26 JA29 JA38 JA42 JA44 JB13 JB23 JB32 JB33 JB38 JB53 JB63 JB69 KA05 KA07 KB14 MA05 MA08 MA13 MA17 MA27 MA35 MA37 MA41 NA22 NA25 PA09 4M104 AA10 BB02 BB13 BB16 ABAA BB19A09 ABC09A01 GB10 5F110 AA02 CC07 DD02 FF03 GG15 HK09 HK16 HL03 HL04 HL07 NN24 NN43 NN80

Claims (7)

[Claims] A plurality of scanning lines formed on an insulating substrate having a light-transmitting property; a plurality of signal lines intersecting with each of the scanning lines; and an intersection between the scanning lines and the signal lines. A switching element composed of a thin film transistor disposed in each of the portions, a pixel electrode connected to the switching element, and an electric field shielding electrode provided at a predetermined voltage and provided via an insulating layer for the signal wiring. An active matrix substrate, wherein the electric field shielding electrode is provided at a position opposite to the pixel electrode with the signal wiring interposed therebetween. 2. The active matrix substrate according to claim 1, wherein an interlayer insulating layer is formed between said pixel electrode and said scanning wiring and signal wiring. 3. The active matrix substrate according to claim 1, wherein the electric field shielding electrode is formed to extend from the scanning wiring. 4. A capacitance holding line for holding capacitance of a pixel electrode between the scanning lines, wherein the electric field shielding electrode is formed to extend from the capacitance holding line. The active matrix substrate according to claim 1. 5. The electric field shielding electrode according to claim 1, wherein a width of said electric field shielding electrode is formed to be larger than a distance between said adjacent pixel electrodes and larger than a width of said signal wiring. 5. The active matrix substrate according to any one of 4. 6. The active matrix substrate according to claim 1, wherein said electric field shielding electrode is formed at a position facing said signal wiring. 7. The electric field shielding electrode according to claim 1, wherein the electric field shielding electrode is formed so as to be displaced in a width direction of the signal wiring at a position facing the signal wiring. An active matrix substrate as described in the above.