JPH10274786A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a display quality and a good producer rate of a liquid crystal display device for which a high numerical aperture is achieved via an interlayer insulating film. SOLUTION: A split area of a picture element electrode 15 is provided on a shading pattern 16 branched from a gate wiring 2 on an insulating substrate like glass and an auxiliary wiring 3. A source wiring 8 is comprised of a transparent conductive film and is provided under the picture element electrode 15 via an interlayer insulating film. Thus, it is possible to obtain a uniform superimposed width between the source wiring and the picture element 15, and this arrangement can eliminate faulty display called block separation occurring in stepper method. Further, since it is possible to hide light leakage between picture elements 15 by the shading pattern 16, shading film does not need to be provided at the side of the counter substrate, and it is possible to improve the numerical aperture by a margin considering a misregistration at the time of sticking the counter substrate to an active matrix substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device using a switching element such as a TFT (thin film transistor).

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display device, a display pattern is formed on a screen by selectively driving pixel electrodes arranged in a matrix. A voltage is applied between the selected pixel electrode and a counter electrode facing the selected pixel electrode, optical modulation of the liquid crystal interposed between these electrodes occurs, and the liquid crystal is visually recognized as a display pattern. As a driving method of a pixel electrode, an active matrix driving method in which individual independent pixel electrodes are arranged and a switching element is connected to each of the pixel electrodes to drive the pixel electrodes is known. TF is used as a switching element for selectively driving a pixel electrode.
T (thin film transistor) elements, MIM (metal insulator metal) elements and the like are generally known. The pixel electrode of such an element is often formed in the same layer as the signal wiring or the scanning wiring, and the pixel electrode is connected to the signal wiring,
It is arranged inside the scanning wiring so as not to contact with each wiring.

FIG. 11 is a partial plan view of an active matrix substrate of a conventional active matrix type liquid crystal display device. FIG. 12 is a sectional view taken along line EE ′ of FIG.

As shown in FIGS. 11 and 12, in order to improve the area (aperture ratio) of the pixel electrode 15, the pixel electrode 15 and the gate wiring 2 serving as a scanning wiring and the signal wiring are interposed via an interlayer insulating film 12. It has also been proposed to form the source wiring 8 in a different layer and overlap the wiring with the pixel electrode 15 (Japanese Patent Laid-Open No. 6-160900).

The technique will be described in more detail. First, an active matrix substrate is provided on a transparent substrate 1 so that a gate wiring 2 and a source wiring 8 are orthogonally different from each other. The contact holes 14 provided in the interlayer insulating film 12 and the pixel electrodes 15 are connected by using the arranged connection lines 11.
Reference numeral 6 denotes a semiconductor layer, 7 denotes an anodic oxide film, and 17 denotes a semiconductor contact layer.

The connection line 11 overlaps with the auxiliary capacitance line 3 via the gate insulating film 5 to form an auxiliary capacitance. At this time, when the connection line 11 is formed of a transparent conductive film such as ITO, the aperture ratio can be improved. In addition, the pixel electrode 15
Overlaps with the gate wiring 2 and the source wiring 8 via the interlayer insulating film 12. With this structure, the aperture ratio of the liquid crystal display device can be improved, and each of the wirings 2 and 8 can be improved.
When the wirings 2 and 8 are formed of a conductive light-shielding material such as a metal, they can be used as a light-shielding film between the pixel electrodes 15.

[0007] A liquid crystal display device is obtained by bonding a liquid crystal layer between the active matrix substrate and the opposing substrate and bonding them together. In this liquid crystal display device, in order to realize color display, a configuration in which a color filter is formed on a counter substrate is most common. The color filter of the counter substrate generally has a structure in which a black matrix is formed in order to prevent color mixing and light leakage, but as described above, in order to reduce manufacturing costs, each wiring also serves as a light shielding film. A configuration in which the black matrix is not provided on the color filter substrate may be employed.

[0008]

Generally, in manufacturing an active matrix substrate, a pixel electrode 15 and the like are formed by exposing a plurality of times using a smaller mask than a substrate called a stepper method. Therefore, the overlapping width of the source line 8 and the pixel electrode 15 is slightly different between the masks, or the layers are formed by superimposing a plurality of layers, resulting in misalignment between layers. In severe cases, a mask called block separation is used. A display defect in which the display is different for each display occurs.

It is effective to use a transparent conductive film such as an ITO film for the connection line 11 for electrically connecting the TFT 10 and the auxiliary capacitance electrode of the pixel so as not to lower the aperture ratio. Therefore, when a transparent film similar to the source wiring 8 is used, the pixel electrode 1 is formed along the source wiring.
Light leakage occurs between the five spaces.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a liquid crystal display device capable of improving display quality, achieving a high aperture ratio, and reducing manufacturing costs. .

[0011]

According to the present invention, there is provided a liquid crystal display device comprising a scanning wiring, a signal wiring, and a switching element connected to the wiring, wherein the scanning wiring is connected to a scanning electrode of the switching element. An active matrix substrate in which the signal wiring is connected to one electrode other than the scanning electrode, and a pixel electrode is connected to the other electrode, and a counter substrate on which a counter electrode is formed are provided so as to face each other with a liquid crystal interposed therebetween. The signal lines are overlapped with an insulating film interposed therebetween, and the pixel electrodes are separated on a light-shielding pattern arranged in parallel with the signal lines.

With this configuration, the overlap width between the signal wiring and the pixel electrode becomes the same, so that a display defect called block separation caused by a stepper method or the like can be eliminated.
In addition, since light leakage between the pixel electrodes can be hidden by a light-shielding pattern, there is no need to provide a light-shielding film on the counter substrate side, and an opening corresponding to a margin that allows for displacement during bonding between the counter substrate and the active matrix substrate. The rate can be improved and the manufacturing cost can be reduced.

Further, the signal wiring may be formed of a transparent conductive film. With this configuration, the aperture ratio can be improved.

Further, an auxiliary capacitance may be formed using a conductive film as the light-shielding pattern. With this configuration, it is possible to further increase the aperture ratio.

Further, a spare wiring connected to the signal wiring is arranged in parallel with the signal wiring, and an adjacent signal wiring and a spare wiring are arranged in one pixel, and a capacity formed between each wiring and a pixel electrode is increased. A signal voltage which is formed so as to be equal to each other and whose polarity is inverted for each line may be applied to the signal wiring. With this configuration, the disconnection redundancy of the signal wiring can be provided, and the yield rate can be improved. At this time, by performing the driving, the shadowing appearing in the vertical direction can be reduced, and the display quality can be improved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a plan view showing a configuration of a part of an active matrix substrate in a liquid crystal display device according to Embodiment 1 of the present invention, and FIG. 2 is a sectional view taken along line AA 'of FIG. 3 is a sectional view taken along line BB 'of FIG. 1, and FIG. 4 is a sectional view taken along line CC' of FIG.

First, a plurality of pixel electrodes 15 are provided in a matrix on the active matrix substrate.
And a source line 8 as a signal line, and an auxiliary capacitance line 3 for forming an auxiliary capacitance is provided so as to be orthogonal to the source line 8 in parallel with the gate line 2. The auxiliary capacitance line 3 is branched up and down at a separation portion of the pixel electrode 15 to form a light-shielding pattern 16. TFT10
The switching element is provided on the gate line 2 as a switching element connected to the pixel electrode 15, and the drain electrode of the TFT 10 is connected to the pixel electrode 15 via the connection line 4 and the contact hole 14 provided in the interlayer insulating film 12. . In the present embodiment, the gate wiring 2 and the auxiliary capacitance wiring 3 are formed of a light-shielding conductive film such as a metal, and the source wiring 8 is formed.
The connection lines 4 are formed of a transparent conductive film. Accordingly, light is shielded between the pixel electrodes 15 by the light-shielding film, and light is transmitted since the source wiring 8 is a transparent conductive film, so that the aperture ratio can be improved.

The method of manufacturing the active matrix substrate according to the present embodiment will be described.
The gate wiring 2 serving also as the gate electrode of FIG. 1 and the auxiliary capacitance wiring 3 are formed thereon with tantalum, aluminum, or the like. At this time, for the purpose of improving the taper shape and improving the reliability of the gate insulating film, the surface of the gate wiring 2, the auxiliary capacitance wiring 3, and the light-shielding pattern 16 may be anodized to form the anodic oxide film 7. . Next, a gate insulating film 5 of silicon nitride, silicon oxide, or the like, a semiconductor layer 6 of amorphous silicon, polysilicon, or the like, n-type amorphous silicon, n
A semiconductor contact layer 17 was sequentially formed of microcrystalline silicon or the like and patterned (see FIG. 2).

Next, the source line 8 and the connection line 4 are formed with a transparent conductive film such as ITO and patterned into a predetermined shape. Further, a photosensitive acrylic resin having a thickness of, for example, 3 μm was formed thereon as an interlayer insulating film 12 by a spin coating method, and the surface was flattened (see FIG. 3).

Here, as the photosensitive acrylic resin, a base polymer was a polymer of methacrylic acid and glycidyl methacrylate, and a naphthoxydiazide-based positive photosensitive agent was used as the photosensitive agent. Next, the resin is exposed according to a desired pattern and developed with an alkaline solution. As a result, only the exposed portion is etched by the alkaline solution, and a contact hole 14 penetrating through the interlayer insulating film 12 is formed (see FIG. 4).

Further, a pixel electrode 15 on which I
A transparent conductive film such as TO is formed, and is exposed and patterned using a stepper method. As a result, the pixel electrode 15 is connected to the T electrode through the contact hole 14 penetrating the interlayer insulating film 12.
This is connected to the connection line 4 connected to the drain electrode of the FT 10. As described above, since the overlapping width of the source wiring 8 and the pixel electrode 15 is constant, it is possible to prevent block separation which is likely to occur when the source wiring 8 and the pixel electrode 15 are formed by a method such as stepper exposure. This is especially true for source line inversion,
This is effective when a drive called a dot inversion drive in which the polarity of a video signal is inverted for each adjacent source line 8 is performed. Further, by providing the contact hole on the light-shielding pattern 16 or each of the light-shielding wirings, the contact portion is not flat, so that the occurrence of light leakage due to poor alignment can be hidden, and the display quality can be improved. At this time, the plurality of pixel electrodes 15 were divided on the gate wiring 2 and the light-shielding pattern 16 (see FIG. 1).

Thereafter, as a counter substrate (not shown), three color filters of red, green, and blue and a counter electrode are provided on a transparent substrate such as a glass substrate, and a liquid crystal is sealed between the active matrix substrates. Paste using materials. At that time, an alignment film or a polarizing plate is used as necessary.

In the active matrix type liquid crystal display device of the present embodiment, since the adjacent pixel electrodes 15 are divided on the light-shielding pattern 16, there is no need to provide a light-shielding film on the opposite substrate side, and the opposite substrate and the active matrix substrate It is possible to improve the aperture ratio and reduce the manufacturing cost by the margin in consideration of the displacement at the time of bonding with the substrate.

Further, since the source wiring 8 is formed of a transparent conductive film such as ITO, the aperture ratio can be improved. Further, since the auxiliary capacitance is formed by using the light-shielding pattern 16, the width of the auxiliary capacitance wiring 3 can be reduced, and the aperture ratio can be further increased.

In the present embodiment, the auxiliary capacitance is provided by providing the auxiliary capacitance line 3 separately from the gate line 2.
Although the m-type is used, the same effect can be obtained by a Cs on Gate structure in which an auxiliary capacitance is formed using the light-shielding pattern 16 branched from the gate wiring 2 shown in FIG.

(Embodiment 2) FIG. 6 is a plan view showing a configuration of an active matrix substrate in an active matrix type liquid crystal display device according to Embodiment 2 of the present invention, and FIG. 7 is a sectional view taken along line DD 'of FIG. Therefore, the description of the same parts as in the first embodiment will be omitted.

In this embodiment, two source wires, that is, the source wires 8a and 8b are used as one set, and both wires are connected at the source electrode 9 to provide disconnection redundancy. Even in this case, by forming the source wirings 8a and 8b with a transparent conductive film, the aperture ratio does not decrease. Further, by making the connection for each pixel in this manner, the disconnection redundancy can be further improved.

As shown in FIG. 8, signals input to adjacent source lines 8a and 8b below one pixel electrode are supplied to sources 1 and 2, respectively, for inputting signals having opposite polarities to each other. By driving using the line inversion drive, the mutual capacitance can be canceled and the shadowing that appears in the vertical direction can be reduced. FIG.
It is more effective to use the dot inversion drive in which the polarity of the source line inversion drive shown in (1) is inverted every horizontal scanning period. At this time, it is more effective to make the capacitance between the source lines 8a and 8b and the pixel electrode 15 the same.

In this embodiment, the auxiliary capacitance is also used as shown in FIG.
Light-shielding pattern 1 branched from the gate wiring 2 shown in FIG.
A similar effect can be obtained also in a Cs on Gate structure in which an auxiliary capacitance is formed by using the C6.

[0031]

As described above, according to the liquid crystal display device of the present invention, the scanning wiring, the signal wiring, and the switching element connected to the wiring are provided, and the scanning wiring is connected to the scanning electrode of the switching element. Connected, an active matrix substrate in which the signal wiring is connected to one electrode other than the scanning electrode, and a pixel electrode is connected to the other electrode, and a counter substrate on which a counter electrode is formed are provided so as to face each other with a liquid crystal interposed therebetween. The pixel electrode and the signal wiring are overlapped via an insulating film, and the pixel electrode is separated on a light-shielding pattern arranged in parallel with the signal wiring, so that the overlap width between the signal wiring and the pixel electrode is reduced. Since they are the same, it is possible to eliminate a display defect called block separation that occurs in the stepper method or the like. In addition, since light leakage between the pixel electrodes can be hidden by a light-shielding pattern, there is no need to provide a light-shielding film on the counter substrate side, and an opening corresponding to a margin that allows for displacement during bonding between the counter substrate and the active matrix substrate. The rate can be improved and the manufacturing cost can be reduced.

Further, since the signal wiring is formed of a transparent conductive film, the aperture ratio can be improved.

Further, since the auxiliary capacitance is formed by using a conductive film as the light-shielding pattern, it is possible to further increase the aperture ratio.

Further, a spare wiring connected to the signal wiring is arranged in parallel with the signal wiring, and an adjacent signal wiring and a spare wiring are arranged in one pixel, and a capacity formed between each wiring and the pixel electrode is increased. By applying a signal voltage whose polarity is inverted for each line to the signal lines, disconnection redundancy of the signal lines can be provided and the non-defective rate can be improved. At this time, shadowing appearing in the vertical direction can be reduced by performing the driving,
The display quality can be improved.

[Brief description of the drawings]

FIG. 1 is a partial plan view of an active matrix substrate of an active matrix liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line A-A 'of FIG.

FIG. 3 is a sectional view taken along line B-B 'of FIG.

FIG. 4 is a sectional view taken along line C-C ′ of FIG. 1;

FIG. 5 is a partial plan view of another active matrix substrate of the active matrix liquid crystal display device according to the first embodiment of the present invention.

FIG. 6 is a partial plan view of an active matrix substrate of an active matrix liquid crystal display device according to a second embodiment of the present invention.

FIG. 7 is a sectional view taken along line D-D ′ of FIG. 6;

FIG. 8 shows drive signals of the active matrix liquid crystal display device according to the second embodiment of the present invention.

FIG. 9 shows another drive signal of the active matrix liquid crystal display device according to the second embodiment of the present invention.

FIG. 10 is a partial plan view of another active matrix substrate of the active matrix liquid crystal display device according to the second embodiment of the present invention.

FIG. 11 is a partial plan view of an active matrix substrate of a conventional active matrix type liquid crystal display device.

12 is a sectional view taken along line E-E 'of FIG.

[Description of Signs] 1 Substrate 2 Gate wiring 3 Auxiliary capacitance wiring 4 Connection line 8 Source wiring 10 TFT (thin film transistor) 12 Interlayer insulating film 14 Contact hole 15 Pixel electrode 16 Light-shielding pattern

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H01L 21/336 H01L 29/78 612Z

Claims (4)

[Claims] 1. A scanning line and a signal line, and a switching element connected to the line are provided, the scanning line of the switching element is connected to the scanning line, and one electrode other than the scanning electrode is connected to the signal line and the other. In a liquid crystal display device in which an active matrix substrate in which a pixel electrode is connected to an electrode and a counter substrate on which a counter electrode is formed are provided so as to face each other with a liquid crystal interposed therebetween, the pixel electrode and the signal wiring form an insulating film. A liquid crystal display device, wherein the pixel electrodes are separated from each other on a light-shielding pattern arranged in parallel with the signal wiring. 2. The liquid crystal display device according to claim 1, wherein said signal wiring is made of a transparent conductive film. 3. The liquid crystal display device according to claim 1, wherein an auxiliary capacitance is formed using a conductive film as the light-shielding pattern. 4. A spare line connected to the signal line is arranged in parallel with the signal line, and an adjacent signal line and spare line are arranged in one pixel, and a capacity formed between each line and a pixel electrode is provided. 2. The liquid crystal display device according to claim 1, wherein a signal voltage whose polarity is inverted is applied to the signal wiring for each line.