JP2000098420A - Active matrix type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix type liquid crystal display device in which good display definition can be obtained by adding sufficient auxiliary capacity while suppressing increase of pixel defect. SOLUTION: An electrode part 52A formed by extending one part of an auxiliary capacity line 52 into a pixel region in order to form auxiliary capacity has plural opening parts 52B. An auxiliary capacity electrode 61 is arranged so as to cover the electrode part 52A including the opening part 52B of the electrode part 52A. In such structure, an oblique electric field from the electrode part 52A of the auxiliary 52 is caused between an auxiliary capacity electrode 61 opposing to the opening part 52B and it, a part other than a part in which the electrode part 52A is opposed directly to the auxiliary capacity electrode 61, that is, a region between the opening part 52B and the auxiliary capacity electrode 61 can be functioned as the auxiliary capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device having an array substrate in which pixel electrodes each having a thin film transistor as a switching element are formed in a matrix.

[0002]

2. Description of the Related Art In recent years, while having a high density and a large capacity,
Practical use of liquid crystal display devices capable of obtaining high-performance and high-definition display has been promoted. There are various types of liquid crystal display devices. Among them, an active matrix type liquid crystal display device including an array substrate provided with pixel electrodes each having a thin film transistor, that is, a TFT as a switching element, provided in a matrix has attracted attention. This active matrix type liquid crystal display device has advantages such as low crosstalk between adjacent pixels, high-contrast display, transmission-type display, and easy area enlargement.

An array substrate applied to this active matrix type liquid crystal display device has a plurality of scanning lines and a plurality of signal lines on an insulating substrate in a direction crossing each other. The array substrate is provided with TFTs at the intersections of these scanning lines and signal lines, and further, pixel electrodes are provided in a matrix in a plurality of regions, i.e., pixel regions partitioned by the scanning lines and the signal lines. I have.

In an active matrix type liquid crystal display device, the potential of a pixel electrode written during a period in which a scanning line is selected changes during a non-selection period due to a parasitic capacitance or an off-leak current of a TFT element, thereby causing a potential fluctuation of an adjacent signal line. , Crosstalk occurs and the contrast ratio decreases. In order to suppress such deterioration in image quality, this type of liquid crystal display device generally has a configuration in which an auxiliary capacitance is formed electrically in parallel with a pixel electrode.

In such an active matrix type liquid crystal display device, a black matrix or BM is provided for the purpose of preventing light leakage between pixel regions. This black matrix is generally arranged on a counter substrate which is arranged to face the array substrate via a liquid crystal layer together with a coloring layer for a color filter. For this reason, it is necessary to consider the misalignment between the array substrate and the opposing substrate, and when the misalignment occurs, the ratio of the aperture portion that transmits light, that is, the aperture ratio decreases.

In order to solve these problems, in recent years, a wiring used as a black matrix by providing a light-shielding organic insulating film on wiring portions such as scanning lines and signal lines provided in a matrix on an array substrate. A BM structure has been proposed. In this wiring BM structure, a pixel electrode is provided in the uppermost layer of a pixel region, and an end of the pixel electrode is overlapped with a wiring portion provided in a matrix. Further, a wiring BM structure in which a coloring layer of a color filter conventionally formed on an opposite substrate is provided on a wiring portion and used as a black matrix instead of an organic insulating film has been proposed. In these wiring BM structures, a high aperture ratio can be realized because there is no decrease in the aperture ratio due to misalignment between the array substrate and the counter substrate.

[0007]

However, such a wiring BM structure has the following disadvantages. That is, in the method in which the wiring portion and the pixel electrode are overlapped with the organic insulating film or the colored layer interposed therebetween, a black matrix in which the signal line and the pixel electrode are arranged at a predetermined distance and the opening is arranged on the opposite substrate. Since the parasitic capacitance between the signal line and the pixel electrode increases as compared with the method defined in the above, the potential of the pixel electrode is easily affected by the adjacent signal line. For this reason, it is necessary to add a larger auxiliary capacitance. In order to increase the auxiliary capacitance without changing the film quality of the array substrate, it is necessary to increase the area of the electrode for forming the auxiliary capacitance or to reduce the thickness of the dielectric forming the auxiliary capacitance. Becomes

In an active matrix type liquid crystal display device, pixel electrodes electrically connected to TFTs are arranged in a matrix from several hundred thousand pixels to one million pixels or more.
For this reason, it is very difficult to manufacture all the pixel regions of all the array substrates without defects, and pixel defects occur at a certain rate. Although there are various causes of the pixel defect, it has been clarified by the defect analysis that the defect due to the short circuit between the electrodes forming the auxiliary capacitance accounts for most of the pixel defect defects.

A defect due to a short circuit between the auxiliary capacitance electrodes occurs almost in proportion to the area of the electrode forming the auxiliary capacitance.
Since the occurrence of defects increases even if the thickness of the dielectric is reduced,
An increase in the auxiliary capacitance directly leads to an increase in pixel defect failure.

In addition, since at least one of the electrodes forming the auxiliary capacitance is formed of a light-shielding metal film, there is a problem that an increase in the area of the electrodes causes a decrease in the aperture ratio of the pixel region. I do.

As described above, in order to prevent image quality deterioration,
Attempting to add a sufficient auxiliary capacitance causes problems such as frequent occurrence of pixel defect defects, which lowers the yield and lowers the aperture ratio of the pixel region.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and provides a sufficient storage capacitor while suppressing an increase in pixel defect defects.
An object of the present invention is to provide an active matrix type liquid crystal display device capable of obtaining good display quality.

[0013]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the object, the present invention provides a scanning line formed on an insulating substrate, a signal line intersecting the scanning line, and a scanning line. A pixel electrode electrically connected to the signal line via a thin film transistor disposed near an intersection of the pixel electrode and the signal line; a first electrode electrically connected to the pixel electrode; An array substrate having a second electrode that forms an auxiliary capacitance by being arranged oppositely with an insulating film interposed therebetween, and an opposing substrate having an opposing electrode arranged opposite to the pixel electrode with a liquid crystal composition interposed therebetween. In the active matrix type liquid crystal display device provided with the first electrode and the second
An active matrix liquid crystal display device, wherein one of the electrodes has a plurality of openings, and the other electrode is disposed so as to continuously cover the plurality of openings. Is provided.

According to the active matrix type liquid crystal display device of the present invention, the electrode portion of the first electrode for forming the auxiliary capacitance has a plurality of openings, and the second electrode has the first electrode.
It is arranged so as to cover the electrode portion including the opening portion of the electrode.

In such a structure, an oblique electric field from the first electrode is generated between the second electrode facing the opening, and an area other than a portion where the first electrode directly faces the second electrode is also assisted. It can function as a capacitor. This makes it possible to form a larger capacitance with respect to the area where the electrodes forming the auxiliary capacitance directly overlap.

Therefore, only the capacitance can be increased without increasing the overlapping area between the pair of electrodes for forming the auxiliary capacitance. For this reason, a decrease in yield due to defective pixel defects can be suppressed, and a sufficient auxiliary capacitance can be formed, so that an active matrix liquid crystal display device having good display quality can be realized. Further, by forming an opening in the light-shielding first electrode wiring, the aperture ratio can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an active matrix type liquid crystal display device according to the present invention will be described below with reference to the drawings. FIG. 1 is a plan view schematically showing one pixel region of an active matrix liquid crystal display device according to an embodiment of the present invention. FIG. 2 is an enlarged plan view showing an enlarged region including the auxiliary capacitance electrode of the active matrix liquid crystal display device shown in FIG. FIG. 3 is a cross-sectional view schematically showing a cross section cut along a dashed-dotted line ABCD in FIG. FIG. 4 is a cross-sectional view schematically showing a cross section cut along a dashed line EF in FIG.

As shown in FIGS. 1 to 4, the array substrate 8
In one pixel region of No. 6, the signal line 50 is disposed so as to be orthogonal to the scanning line 51 and the auxiliary capacitance line 52 as the first electrode via the interlayer insulating film 76. The auxiliary capacitance line 51 is formed of a light-shielding metal film. The auxiliary capacitance line 52 is provided in the same layer as the scanning line 51 and is formed in parallel with the scanning line 51.

An area defined by the signal line 50 and the auxiliary capacitance line 52 defines an opening and corresponds to one pixel area. A part of the auxiliary capacitance line 52 is disposed opposite to an auxiliary capacitance electrode 61 as a second electrode formed of a light-transmitting polysilicon film via a gate insulating film 62 made of a silicon oxide film. And an auxiliary capacitance electrode 61 that functions as an electrode portion 52A that forms an auxiliary capacitance.
The electrode portion 52A of the auxiliary capacitance line 52 is formed in a comb shape having a plurality of openings 52B. This opening 52B has a long side along the signal line 50,
It is formed in a rectangular shape having a short side along the scanning line 51. The apertures 52B are arranged in parallel along the scanning line 51.

An auxiliary capacitance line 52 for forming an auxiliary capacitance
The electrode portion 52A including the opening portion 52B, and the auxiliary capacitance electrode 6
1 is arranged in a region extending from the storage capacitor line 52 into the pixel region.

The pixel electrode 53 is arranged on the signal line 50 and the auxiliary capacitance line 52 such that their peripheral portions overlap. The thin film transistor or TFT 75 functioning as a switching element is disposed near the intersection of the signal line 50 and the scanning line 51. As the TFT 75, an N-channel lightly doped drain, that is, an element having an Nch LDD structure is used.

The TFT 75 includes a semiconductor film 87 having a drain region 66 and a source region 67 formed of a polysilicon film in the same layer as the auxiliary capacitance electrode 61, and one of the scanning lines 51 arranged via the gate insulating film 62. And a gate electrode 63 composed of a portion. The drain region 66 is electrically connected to the signal line 50 via a contact hole 77 to form a drain electrode 88. The source region 67 is electrically connected to the pixel electrode 53 by a contact electrode 80 via a contact hole 78, and forms a source electrode 89.

The contact electrode 80 electrically connects the source electrode 89 of the TFT 75, the pixel electrode 53, and the auxiliary capacitance electrode 61. That is, the source region 6
Reference numeral 7 is electrically connected to the first contact electrode 67C via the contact hole 78. The pixel electrode 53
It is electrically connected to the second contact electrode 53C via the contact holes 83A and 83B. The contact region 68 of the auxiliary capacitance electrode 61 is electrically connected to the third contact electrode 61C via the contact hole 79.

The first contact electrode 67C, the second contact electrode 53C, and the third contact electrode 61C
Are connected by the extended contact electrode 80 and are electrically connected. Thereby, the source electrode 89, the pixel electrode 53, and the auxiliary capacitance electrode 61 of the TFT 75 are
It has the same potential.

The auxiliary capacitance of the active matrix type liquid crystal display device includes an auxiliary capacitance electrode 61 having the same potential as the source electrode 89 and the pixel electrode 53, and an auxiliary capacitance disposed opposite to the auxiliary capacitance electrode 61 via the gate insulating film 62. It is formed by a potential difference between the capacitance line 52 and the electrode portion 52A. The electrode portion 52A is formed in a comb shape having a plurality of openings 52B, and the auxiliary capacitance electrode 61 is arranged to face the electrode portion 52A including the openings 52B. The pitch of the comb-shaped electrode portion 52A is, for example, 3 to 4 μm, although it depends on the magnitude of the potential difference between the electrode portion 52A and the auxiliary capacitance electrode 61.

In such a structure, an oblique electric field from the electrode portion 52A of the auxiliary capacitance line 52 is generated between the auxiliary capacitance electrode 61 facing the opening 52B, and the electrode portion 52A and the auxiliary capacitance electrode 61 are directly connected. Other than the opposing part, that is, the opening 5
The region between 2B and the auxiliary capacitance electrode 61 can also function as an auxiliary capacitance.

Thus, it is possible to form a larger capacitance with respect to the area where the electrodes forming the auxiliary capacitance directly overlap. Therefore, only the capacitance can be increased without increasing the overlapping area between the pair of electrodes for forming the auxiliary capacitance. For this reason, a decrease in yield due to defective pixel defects can be suppressed, and a sufficient auxiliary capacitance can be formed, so that an active matrix liquid crystal display device having good display quality can be realized.

Further, by forming a hole in the electrode portion 52A formed of a metal film having a light-shielding property located in the pixel region, the aperture ratio of the pixel region can be improved.

Next, a method of manufacturing the active matrix type liquid crystal display device having the above-described structure will be described with reference to FIGS. First, an amorphous silicon film, i.e., an a-Sl film is formed on a transparent insulating substrate 60 such as a high strain point glass substrate or a quartz substrate by a CVD method or the like.
m. Then, after annealing at 450 ° C. for 1 hour, an excimer laser beam is irradiated and a-Si
The film is polycrystallized.

Thereafter, the polycrystallized silicon film, that is, the polysilicon film is patterned by a photo-etching method, and the TFT provided in each pixel region in the display region, that is, the channel layer of the pixel TFT 75, and the driving circuit region , The channel layers of the circuit TFTs 69 and 72 are formed, and the auxiliary capacitance electrode 61 for forming the auxiliary capacitance is formed.

Subsequently, a silicon oxide film, that is, a SiOx film is deposited on the entire surface of the substrate 60 to a thickness of about 100 nm by the CVD method, and a gate insulating film 62 is formed. Subsequently, tantalum (Ta) and chromium (C
r), a simple substance such as aluminum (Al), molybdenum (Mo), tungsten (W), copper (Cu), a laminated film thereof, or an alloy film thereof is 400 nm in thickness.
And then patterned into a predetermined shape by a photo-etching method.

As a result, the scanning lines 51, the gate electrodes 63 of the pixel TFTs 75 extending along the scanning lines 51, the auxiliary capacitance lines 52, the auxiliary capacitance lines 52 extend, and the auxiliary lines extend through the gate insulating film 62. The electrode portion 52A including the opening portion 52B facing the capacitor electrode 61, the gate electrodes 64 and 65 of the circuit TFTs 69 and 72, and various wirings in the drive circuit region are formed. By this patterning, the auxiliary capacitance line 5
The second electrode portion 52A is formed in a comb shape, and an opening portion 52B is formed.

Subsequently, these gate electrodes 63, 64,
Impurities are implanted into the polysilicon film by ion implantation or ion doping using 65 as a mask. As a result, the drain region 66 and the source region 67 of the pixel TFT 75, the contact region 68 of the auxiliary capacitance electrode 61,
Then, the source region 70 and the drain region 71 of the Nch type circuit TFT 69 are formed. In this embodiment, for example, 5 × 10 ¹⁵ atoms / cm ² at an acceleration voltage of 80 keV.
A high concentration of phosphorus was injected under the conditions of PH ₃ / H ₂ at a dose amount of.

Subsequently, the pixel TFT 75 and the Nch-type circuit TFT 69 in the drive circuit area are covered with a resist so as to prevent impurities from being implanted, and then the Pch-type circuit TFT 72 is covered.
Using the gate electrode 64 as a mask, an impurity is implanted into the polysilicon film. Thereby, the Pch type circuit T
The source region 73 and the drain region 74 of the FT 72 are formed. In this embodiment, 5 × at an acceleration voltage of 80 keV
B ₂ H ₆ / H at a dose of 10 ¹⁵ atoms / cm ²
_Under the conditions of ₂ , boron was injected at a high concentration.

Subsequently, the pixel TFT 75 and the circuit TFT 6
In order to form an Nch-type LDD region in 9, an impurity is implanted and the entire substrate is annealed to activate the impurity.

Subsequently, a silicon dioxide film, ie, SiO ₂ is deposited on the entire surface of the substrate 60 to a thickness of about 500 nm, and an interlayer insulating film 76 is formed. Subsequently, the pixel TFT is formed on the gate insulating film 62 and the interlayer insulating film 76 by a photo-etching method.
75, a contact hole 78 reaching the drain region 66 and a contact hole 78 reaching the source region 67; a contact hole 79 reaching the contact region 68 of the auxiliary capacitance electrode 61;
A contact hole reaching the drain region 73 and the drain regions 71 and 74 is formed.

Subsequently, Ta, Cr, Al, Mo, W, C
A simple substance such as u, a laminated film thereof, or an alloy film thereof is deposited to a thickness of about 500 nm, and is patterned into a predetermined shape by a photoetching method.

Thus, the signal line 50 is formed, and the drain region 66 of the pixel TFT 75 and the signal line 50 are electrically connected to form the drain electrode 88. At the same time, the first contact electrode 67C electrically connected to the source region 67 of the pixel TFT 75, the second contact electrode 53C electrically connected to the pixel electrode 53 formed later, and the auxiliary capacitance electrode 61 An electrically connected third contact electrode 61C is formed. At this time,
The source region 67 and the first contact electrode 67C are electrically connected to form a source electrode 89.

Further, at the same time, the first contact electrode 67
C, a contact electrode 80 for electrically connecting the second contact electrode 53C and the third contact electrode 61C is formed. Further, at the same time, various wirings of the circuit TFTs 69 and 72 in the drive circuit area are formed. The first contact electrode 67C, the second contact electrode 53C, the third contact electrode 61C, and the contact electrode 80 are all integrally formed.

Subsequently, a silicon nitride film, that is, SiNx is formed on the entire surface of the substrate 60, and a protective insulating film 82 is formed. Then, a contact hole 83A reaching the second contact electrode 53C is formed in the protective insulating film 82 by a photoetching method.

Subsequently, for example, coloring layers 84R, 84G, and 84B in which red, blue, and green pigments are dispersed are formed to a thickness of about 2 μm for each pixel region. Then, a contact hole 83B from the pixel electrode 53 to be described later to the second contact electrode 53C is formed.

Subsequently, a transparent conductive member, for example, indium-tin-oxide, ie, ITO, is formed to a thickness of about 100 nm on the entire surface by a sputtering method, and is patterned into a predetermined shape by a photo-etching method. Thereby, the pixel electrode 53 is formed, and the pixel electrode 5 is formed.
3 is electrically connected to the second contact electrode 53C, the source electrode 67 of the pixel TFT 75 is electrically connected to the pixel electrode 53 via the contact electrode 80, and the pixel electrode 53 and the auxiliary capacitance electrode 61 are connected to each other. Make an electrical connection.

Through the above steps, the array substrate 86 of the active matrix type liquid crystal display device is obtained. On the other hand, for example, an ITO film is formed by a sputtering method on a glass substrate 90 as a transparent insulating substrate, and is patterned to form a counter electrode 91 which is a transparent electrode.

Through these steps, the opposing substrate 92 of the active matrix type liquid crystal display device is obtained. Subsequently, the pixel electrode 53 side of the array substrate 86 and the counter substrate 92
A low-tone cure type polyimide is applied by printing on the entire surface on the side of the counter electrode 91, and a rubbing process is performed so that the respective alignment axes are 90 ° when the substrates 86 and 92 are opposed to each other. , 93 are formed.

Subsequently, by disposing the spherical spacer 55 between the two substrates 86 and 92, a gap having a predetermined width is maintained between the two substrates, and the two substrates are assembled facing each other to form a cell. Then, the nematic liquid crystal 100 is injected into the gap from the injection port and sealed. And both substrates 8
By attaching a deflection plate to the 6,92 insulating substrates 60, 90, an active matrix type liquid crystal display device can be obtained.

The array substrate 86 thus constructed
In, at least one electrode 61 of a pair of electrodes 52 and 61 forming an auxiliary capacitance in a pixel region is formed of a light-transmitting electrode, and one of the electrodes 61 is interposed with a gate insulating film 62 therebetween. An opening 52B of a predetermined size is provided so that the other electrode 52A arranged oppositely has a comb shape.

The auxiliary capacitance is formed by an electric field between one electrode 61 and the other electrode 52A. Further, an oblique electric field from the other electrode 52A is generated between the one electrode 61 facing the opening 52B, and a region other than a portion where the one electrode 61 directly faces the other electrode 61 is also used as an auxiliary capacitance. Can work.

That is, since the auxiliary capacitance is affected by an oblique electric field that reaches the electrode 61 from the comb-shaped electrode 52A toward the opening 52B, the auxiliary capacitance is limited by the area where the pair of electrodes forming the auxiliary capacitance directly overlap. , A larger capacity can be formed. In other words, the auxiliary capacitance formed between a pair of electrodes having such a structure is a pair of electrodes having no aperture, despite one electrode area being reduced in area by the aperture. It is almost equal to the auxiliary capacitance formed by the electrode.

At this time, the capacitance to be formed is
It has been confirmed that when the pitch between 2A and the opening 52B is about 3 to 4 μm, the capacitance is equivalent to that of an electrode having no opening when the potential difference is the same.

In this embodiment, one of the electrodes 61 for forming the auxiliary capacitance is a light-transmitting polysilicon film, and the electrode 52 formed of a light-shielding metal film is used.
By making A a comb shape, some light is transmitted. At this time, the pair of electrodes 61 and 52A are arranged in the pixel region, and the pixel electrode 53 is formed on the upper layer of the comb-shaped electrode 52A.
Are arranged, a part of the transmitted light passes through the pixel region, and an effect of improving the aperture ratio can be expected.

For this reason, it is possible to form a more sufficient auxiliary capacitance without increasing the electrode area, to prevent the image quality from deteriorating, to suppress the occurrence of defective pixels, and to improve the yield. It is possible to do.

Further, even if the electrode area is reduced, it is possible to form an auxiliary capacitance substantially equal to the state before the reduction, so that the aperture ratio can be improved. Further, in this embodiment, the case where the colored layer 84 (R, G, B) is arranged on the array substrate has been described, but the same effect can be obtained also when an organic insulating film is used.

Next, the structure of an array substrate applied to an active matrix type liquid crystal display device according to another embodiment of the present invention will be described. FIG. 5 is an enlarged plan view in which an area including an auxiliary capacitance electrode of an active matrix liquid crystal display device according to another embodiment of the present invention is enlarged. Here, the same components as those of the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.

That is, as shown in FIG. 5, a pair of electrodes for forming a storage capacitor includes an electrode portion 52 C extending from the storage capacitor line 52 into the pixel region and a gate insulating film 62.
And an auxiliary capacitance electrode 61 disposed opposite to the electrode portion 52C through the storage capacitor electrode 61C.

The auxiliary capacitance electrode 61 is formed on the glass substrate 60 by a polysilicon film disposed in the same layer as the semiconductor film 87 of the TFT 75. The electrode section 52
C denotes the gate insulating film 6 disposed on the auxiliary capacitance electrode 61.
2 is formed of a single substance such as tantalum, chromium, aluminum, molybdenum, tungsten, copper, or the like, a laminated film thereof, or an alloy film thereof, which is disposed in the same layer as the gate electrode 63 of the TFT 75.

The electrode section 52C includes an opening 52D. The opening 52D has a long side along the scanning line 51,
It is formed in a rectangular shape having a short side along the signal line 50. The rectangular openings 52D are arranged in parallel along the extending direction of the signal line 50.

Even with such a shape, by appropriately setting the pitch between the electrode portion 52C and the opening portion 52D,
It is possible to form a capacitance substantially equal to an auxiliary capacitance formed between a pair of electrodes having no opening.

As a result, similarly to the above-described embodiment, it is possible to form a more sufficient auxiliary capacitance without increasing the electrode area, to prevent the image quality from deteriorating, and to reduce the pixel defect. The occurrence of defects can be suppressed, and the yield can be improved.

Further, even if the electrode area is reduced, it is possible to form an auxiliary capacitance substantially equal to the state before the reduction, so that the aperture ratio can be improved. Next, a structure of an array substrate applied to an active matrix liquid crystal display device according to another embodiment of the present invention will be described.

FIG. 6 is an enlarged plan view showing an enlarged region including an auxiliary capacitance electrode of an active matrix type liquid crystal display device according to another embodiment of the present invention. Here, the same components as those of the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.

That is, as shown in FIG. 6, a pair of electrodes for forming the auxiliary capacitance include an electrode portion 52E extending from the auxiliary capacitance line 52 into the pixel region and a gate insulating film 62.
And an auxiliary capacitance electrode 61 disposed opposite to the electrode portion 52E with the auxiliary capacitance electrode 61 interposed therebetween.

The auxiliary capacitance electrode 61 is formed on the glass substrate 60 by a polysilicon film disposed in the same layer as the semiconductor film 87 of the TFT 75. The electrode section 52
E denotes a gate insulating film 6 disposed on the auxiliary capacitance electrode 61.
2 is formed of a single substance such as tantalum, chromium, aluminum, molybdenum, tungsten, copper, or the like, a laminated film thereof, or an alloy film thereof, which is disposed in the same layer as the gate electrode 63 of the TFT 75.

The electrode section 52E includes an opening 52F. The openings 52F are formed in a substantially square shape and arranged in a matrix. Even with such a shape, by setting the pitch of the electrode portion 52E and the opening portion 52F appropriately, it is possible to form a capacitance substantially equivalent to an auxiliary capacitance formed between a pair of electrodes having no opening portion. Becomes possible.

As a result, similarly to the above-described embodiment, it is possible to form a more sufficient auxiliary capacitance without increasing the electrode area, to prevent the image quality from deteriorating, and to reduce the pixel defect. The occurrence of defects can be suppressed, and the yield can be improved.

Further, even if the electrode area is reduced, it is possible to form an auxiliary capacitance substantially equal to the state before the reduction, so that the aperture ratio can be improved. As described above, according to the active matrix liquid crystal display device of the present invention, the electrode portion of the auxiliary capacitance line as the first electrode for forming the auxiliary capacitance has a plurality of openings, and the second electrode The auxiliary capacitance electrode is disposed so as to cover the electrode portion including the opening portion of the electrode portion.

In such a structure, an oblique electric field from the first electrode is generated between the second electrode facing the opening and the portion other than the portion where the first electrode and the second electrode directly face each other, that is, the opening The region between the portion and the second electrode can also function as an auxiliary capacitance.

Thus, it is possible to form a larger capacitance with respect to the area where the electrodes forming the auxiliary capacitance directly overlap. Therefore, only the capacitance can be increased without increasing the overlapping area between the pair of electrodes for forming the auxiliary capacitance. For this reason, a decrease in yield due to defective pixel defects can be suppressed, and a sufficient auxiliary capacitance can be formed, so that an active matrix liquid crystal display device having good display quality can be realized.

Further, by forming an opening in the light-shielding electrode, the aperture ratio can be improved. In all the embodiments described above, the active matrix type liquid crystal display device using a polysilicon film as a semiconductor layer of a TFT has been described. However, the present invention relates to a semiconductor layer such as an amorphous silicon film such as an amorphous silicon film. It is needless to say that the present invention can also be applied to an active matrix type liquid crystal display device using.

[0069]

As described above, according to the present invention, it is possible to obtain an excellent display quality by adding a sufficient auxiliary capacitance while suppressing an increase in pixel defect defects. A liquid crystal display device can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing one pixel region of an active matrix liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view in which a region including an auxiliary capacitance electrode of the active matrix liquid crystal display device shown in FIG. 1 is enlarged.

FIG. 3 is a sectional view schematically showing a section cut along a dashed line ABCD in FIG. 2;

FIG. 4 is a cross-sectional view schematically showing a cross section cut along a dashed line EF in FIG. 2;

FIG. 5 is an enlarged plan view in which an area including an auxiliary capacitance electrode of an active matrix type liquid crystal display device according to another embodiment of the present invention is enlarged.

FIG. 6 is an enlarged plan view in which an area including an auxiliary capacitance electrode of an active matrix liquid crystal display device according to another embodiment of the present invention is enlarged.

[Explanation of symbols]

 Reference Signs List 50 signal line 51 scanning line 52 auxiliary capacitance line 52A electrode portion 52B opening portion 53 pixel electrode 60 insulating substrate 61 auxiliary capacitance electrode 62 gate insulating film 75 thin film transistor 80 contact electrode 86 Array substrate 92: Counter substrate 100: Liquid crystal composition

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 KA04 KA07 KA16 KA18 KB14 KB23 MA07 MA14 MA15 MA16 MA18 MA19 MA20 MA22 MA28 MA35 MA37 MA41 NA07 NA24 NA25 NA27 NA28 NA29 PA06 PA08 QA07

Claims (9)

[Claims] A scanning line formed on an insulating substrate; a signal line intersecting the scanning line; and a thin film transistor disposed near an intersection of the scanning line and the signal line. A pixel electrode that is electrically connected, a first electrode that is electrically connected to the pixel electrode, and a second electrode that forms an auxiliary capacitance by being arranged opposite to the first electrode via an insulating film. An active matrix liquid crystal display device comprising: an array substrate having: a counter electrode having a counter electrode disposed to face the pixel electrode with a liquid crystal composition interposed therebetween; An active matrix liquid crystal display device, wherein one of the electrodes has a plurality of openings, and the other electrode is arranged to continuously cover the plurality of openings. 2. The active matrix type liquid crystal display device according to claim 1, wherein said other electrode is formed by a light transmissive electrode. 3. The active matrix type liquid crystal display device according to claim 2, wherein said other second electrode is formed of a semiconductor film of the same layer as a channel of said thin film transistor. 4. The active matrix type liquid crystal display device according to claim 3, wherein said second electrode is a semiconductor film made of a polycrystalline silicon thin film. 5. The device according to claim 1, wherein the other electrode is connected to the pixel electrode via a contact electrode.
4. The active matrix type liquid crystal display device according to item 1. 6. The active matrix liquid crystal display device according to claim 5, wherein said contact electrode is formed in the same layer as a contact electrode for electrically connecting said thin film transistor and said pixel electrode. 7. The active matrix liquid crystal display device according to claim 1, wherein said one electrode is formed of a light-shielding metal film. 8. The active matrix type liquid crystal display device according to claim 7, wherein said one electrode is formed in the same layer as said scanning line. 9. The active matrix type liquid crystal display device according to claim 1, wherein said one electrode has a comb shape.