JPH1048672A - Active matrix type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to increase the yield of production, to obtain a large opening rate and to attain brightness by forming leading-out wirings of common electrodes, video signal electrodes (source electrodes) and pixel electrodes (drain electrodes) as different layers by insulating films. SOLUTION: Gate electrodes 10 and common electrodes 16 consisting of Cr are formed on a glass substrate 1 and gate insulating films consisting of silicon nitride (SiN) films are so formed as to cover the respective electrodes. Amorphous silicon (a-Si) films 30 are formed via the gate insulating films on the gate electrodes 10 to form active layers of transistors. The drain electrodes 14 and source electrodes 15 consisting of Mo are so formed as to be superposed one part of the patterns of the a-Si films 30. Protective insulating films consisting of SiN films are formed to cover all of the respective electrodes and films. Further, the common electrodes 16 are formed at the same layer as the layer of the gate electrodes 10. The drain electrodes 14, the source electrodes 15 which are liquid crystal driving electrodes and the common electrodes 16 are insulated and separated by the gate insulating films.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image of OA equipment, etc.
The present invention relates to a structure of an active matrix type liquid crystal display device used as a display device for character information.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device (TFT-LCD) using a thin film transistor (hereinafter referred to as a TFT) in a matrix on an insulating substrate such as glass and using the thin film transistor as a switching element is a high quality flat panel. Expectations are great for displays. In a conventional active matrix type liquid crystal display device, a transparent electrode formed on two substrates and opposed to each other is used as an electrode for driving a liquid crystal layer. This is due to the adoption of a display system represented by a twisted nematic display system that operates by making the direction of the electric field applied to the liquid crystal substantially perpendicular to the substrate surface.

On the other hand, Japanese Patent Publication No. Sho 63-21907 discloses a system using a comb-shaped electrode as a system in which the direction of an electric field applied to the liquid crystal is substantially parallel to the substrate surface.

[0004]

In the above-mentioned prior art, the liquid crystal layer is driven by interdigitated comb-shaped electrodes, but light can be transmitted because the comb-shaped electrodes are used as the driving electrodes. It is difficult to increase the effective area (hereinafter referred to as the aperture ratio). In principle, the electrode width of the comb-teeth electrode should be 1 to
If the diameter is reduced to about 2 μm, the aperture ratio can be increased to a practical level. However, in practice, it is extremely difficult to form such fine lines uniformly and without disconnection over the entire surface of a large substrate. That is, in the above-described conventional technology, since the interdigitating comb-shaped electrodes are used, the pixel aperture ratio and the manufacturing yield are in a trade-off relationship, and it is difficult to provide a liquid crystal display device having a bright image at low cost. Met.

Further, the above-mentioned comb-shaped electrode of the prior art is formed in a plane, and a large margin between the electrodes has to be taken. Further, the above publication does not disclose the state of intersection of the reference electrode with another electrode.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a bright active matrix type liquid crystal display device having a high aperture ratio.

[0007]

Means for Solving the Problems On one of the pair of substrates, there are provided a plurality of scanning signal electrodes, a plurality of video signal electrodes intersecting the scanning signal electrodes in a matrix, and corresponding intersections of these electrodes. And a plurality of thin film transistors formed.

Further, a pixel having a common electrode and a pixel electrode connected to a thin film transistor is formed in each region surrounded by a plurality of scanning signal electrodes and video signal electrodes.

The common electrode has a portion extending in a direction substantially equal to the direction in which the video signal electrode extends, and a lead wiring for connecting to a common electrode of a pixel adjacent in a direction parallel to the corresponding scanning signal electrode. And the pixel electrode has a portion extending in a direction substantially equal to the direction in which the corresponding video signal electrode extends.

A portion of the pixel electrode extending perpendicular to the scanning signal electrode and a portion of the common electrode extending in a direction substantially equal to the direction in which the video signal electrode extends are formed in a layer higher than the common electrode lead-out wiring. Is done.

As described above, the portion of the pixel electrode extending in the direction substantially equal to the direction in which the video signal electrode extends and the portion of the common electrode extending in the direction substantially equal to the direction in which the video signal electrode extends are formed by the common electrode. When formed in a layer above the lead wiring, a parasitic electric field that disturbs the orientation of the liquid crystal display device can be shielded, so that the area of the light shielding layer can be reduced and the aperture ratio can be improved.

When a portion of the common electrode extending in the direction substantially equal to the direction in which the video signal electrode extends is connected to a part of the corresponding common electrode lead-out wiring through a through hole, the arrangement is three-dimensional. Therefore, the common electrode and the signal electrode can be formed close to each other, and the aperture ratio can be improved.

If the common electrode lead-out lines are formed in the same layer as the scanning signal electrodes, their structure can be formed by one mask, so that the misalignment of the photomask is relatively reduced, Increases manufacturing process latitude.

The portion of the common electrode extending in the direction substantially equal to the direction in which the video signal electrode extends is formed in the same layer as the portion of the pixel electrode extending in the direction substantially equal to the direction in which the video signal electrode extends. Or, if a portion of the common electrode extending in a direction substantially equal to the direction in which the video signal electrode extends is formed on the same layer as the video signal electrode, a portion of the common electrode perpendicular to the scanning signal electrode is formed as a pixel electrode. The portion that extends in the direction substantially the same as the direction in which the video signal electrode extends, or the same photomask that forms the video signal electrode, and the same process can be used, so the mask misalignment is relatively reduced. In addition, the manufacturing cost can be reduced.

Further, when at least a part of a portion extending in a direction substantially equal to a direction in which the video signal electrode of this configuration extends is in contact with the liquid crystal layer, a stronger electric field can be generated in the liquid crystal layer. Therefore, the liquid crystal can be driven with a low applied voltage.

Further, by forming the surface of the common electrode having such a structure as an electrode constituted by a metal electrode covered with a self-oxidizing film or a self-nitriding film, the intersection of the electrode and the electrode, in particular, the common electrode and the pixel When the electrodes are overlapped with each other, the occurrence of a short circuit between them can be prevented, so that pixel defects can be reduced. In addition, since it also functions as a self-protecting film, even if it is formed so as to be in contact with the liquid crystal layer, corrosion or the like hardly occurs.

When the pixel electrode and the common electrode are formed in different layers at least in part via an insulating film, the pixel electrode and the common electrode can be overlapped with each other, so that the pixel aperture ratio can be increased. Further, since the additional capacitance can be formed by the overlapping portion of the pixel electrode and the common electrode, and the voltage holding characteristic can be improved, it is possible to compensate for the decrease in the image quality due to the decrease in the liquid crystal resistance and the decrease in the off-resistance of the TFT.

The following configuration is also conceivable as another configuration.

It has a pair of substrates, and a liquid crystal layer sandwiched between the pair of substrates. One of the pair of substrates has a plurality of scanning signal electrodes and a plurality of images intersecting them in a matrix. A liquid crystal display device having a signal electrode and a plurality of thin film transistors formed corresponding to respective intersections of these electrodes, wherein the liquid crystal display device is common to respective regions surrounded by a plurality of scanning signal electrodes and a plurality of video signal electrodes. A pixel having an electrode and a pixel electrode connected to the thin film transistor is formed, and the common electrode is adjacent to a portion extending in a direction substantially equal to the direction in which the video signal electrode extends and parallel to the scanning signal electrode. The pixel electrode has a lead line for connecting to a common electrode of the pixel, and the pixel electrode has a portion extending in a direction parallel to the scanning signal electrode.

The lead wire of the common electrode is formed in the same layer as the scanning signal electrode, and the portion of the common electrode extending in a direction substantially equal to the direction in which the video signal electrode extends is a portion of the video signal electrode of the corresponding pixel electrode. A portion extending in a direction substantially equal to the extending direction, or the same layer as the video signal electrode, is formed in a different layer from the lead wiring of the common electrode via an insulating film,
The portion of the common electrode that is perpendicular to the extraction wiring and the scanning signal electrode is connected through a through hole.

With such a configuration, the degree of freedom in designing the shape of the common electrode or the pixel electrode is increased, and the aperture ratio can be improved because it is not necessary to use a comb-shaped electrode.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] FIGS. 1 to 4 are a sectional view and a plan view of a unit pixel showing an operation principle of a first embodiment of the present invention. A gate electrode 10 made of Cr and a common electrode (common electrode) 16 are formed on a glass substrate 1, and a gate insulating film 20 made of a silicon nitride (SiN) film is formed so as to cover these electrodes.
Was formed. An amorphous silicon (a-Si) film 30 is formed on the gate electrode 10 with the gate insulating film 20 interposed therebetween to form an active layer of a transistor. A drain electrode 1 made of Mo so as to overlap a part of the pattern of the a-Si film 30.
4, a source electrode 15 was formed, and a protective insulating film 23 made of a SiN film was formed so as to cover all of them. The alignment control films ORI1 and ORI2 made of polyimide were formed on the surface of an active matrix substrate on which the unit pixels constituted as described above were arranged in a matrix, and rubbing was performed on the surface. Alignment control film O also rubbed
A counter substrate 508 having RI1 and ORI2 formed on its surface;
A liquid crystal composition containing rod-shaped liquid crystal molecules 513 was sealed between the active matrix substrates, and a polarizing plate 505 was disposed on the outer surfaces of the two substrates. The liquid crystal molecules 513 have a stripe-shaped source electrode 15 when there is no electric field (FIGS. 1 and 2).
And a slight angle with respect to the longitudinal direction of the common electrode 16,
That is, the angle between the long axis (optical axis) of the liquid crystal molecules and the direction of the electric field (perpendicular to the longitudinal direction of the source electrode and the common electrode) is 4
It is oriented to have 5 ° or more and less than 90 °. still,
The orientation of the liquid crystal molecules at the interface with the upper and lower substrates was parallel to each other. The dielectric anisotropy of the liquid crystal molecules is positive. here,
When a voltage is applied to the gate electrode 10 of the TFT to turn on the TFT, a voltage is applied to the source electrode 15 and the source electrode 1
When an electric field E1 is induced between the 5-common electrode 16, FIG.
Also, as shown in FIG. 4, the liquid crystal molecules change their direction in the direction of the electric field. By arranging the polarization transmission axes of the two polarizing plates 505 disposed on the upper and lower substrates at a predetermined angle AGL1, it becomes possible to change the light transmittance by applying an electric field.
As described above, according to the display method of the present invention, it is possible to provide a display that provides a contrast without a transparent electrode, which is conventionally required. For this reason, all the steps relating to the formation of the transparent electrode can be omitted, so that the manufacturing cost can be reduced. Further, in the conventional display method using a transparent electrode, a dark state is obtained by raising the long axis of liquid crystal molecules from the substrate interface by applying a voltage and setting the birefringence phase difference to zero.
The viewing angle direction is only the front direction, that is, the direction perpendicular to the substrate interface, and if it is slightly tilted, a sub-refractive phase difference appears, and in a normally open type display, light leaks and causes a decrease in contrast and inversion of gradation level . However, in the display method of this embodiment, the major axis of the liquid crystal molecules is substantially parallel to the substrate and does not rise even when a voltage is applied. Therefore, there is an effect that the change in brightness when the viewing angle direction is changed is small and the viewing angle characteristics are greatly improved.

Further, in this embodiment, the common electrode 16 is formed on the same layer as the gate electrode 10, and the drain electrode 14, the source electrode 15 which is a liquid crystal drive electrode, and the common electrode 16 are insulated and separated by the gate insulating film 20. Further, the conventionally used comb-shaped electrode is abolished, and the source electrode 15 and the common electrode 16 are overlapped with the gate insulating film 20 interposed therebetween. As described above, by insulating and separating the drain electrode 14 and the source electrode 15 from the common electrode 16, the degree of freedom in designing the planar pattern of the source electrode 15 and the common electrode 16 is increased, and the pixel aperture ratio can be improved. Further, since the overlapping portion of the source electrode 15 and the common electrode 16 acts as an additional capacitance connected in parallel with the liquid crystal capacitance, the ability to hold the liquid crystal applied voltage can be improved.
Such an effect cannot be obtained by the conventional comb-shaped electrode, and is achieved only by insulating and isolating the common electrode 16 from the drain electrode 14 and the source electrode 15. As described above, since the drain electrode 14 and the source electrode 15 and the common electrode 16 are formed in different layers, the degree of freedom in designing a plane pattern is increased. Therefore, the electrode shape is not limited to this embodiment, and various and various structures are available. Can be adopted.

Embodiment 2 FIG. 5 is a plan view of a unit pixel according to a second embodiment of the present invention. The sectional structure of this embodiment is the same as that of the first embodiment (FIG. 1). The present embodiment is characterized in that the common electrode 16 has a cross shape and the source electrode 15 has a ring shape. The common electrode 16 and the source electrode 15 overlap each other at locations denoted by C1, C2, C3, and C4 to form an additional capacitance. According to the present embodiment, since the distance between the common electrode 16 and the gate electrode 10 can be increased, a short circuit failure between the common electrode 16 and the gate electrode 10 can be prevented. Further, by forming the source electrode 15 in a ring shape, even if a disconnection occurs
Power is supplied to the entire source electrode as long as there is no disconnection beyond the point, and normal operation is possible. That is, the present structure has redundancy against disconnection and can improve the yield.

[Embodiment 3] FIG. 6 is a plan view of a unit pixel according to a third embodiment of the present invention. The sectional structure of this embodiment is the same as that of the first embodiment (FIG. 1). This embodiment is characterized in that the source electrode 15 has a ring shape as in the second embodiment, and the common electrode 16 has a T-shape. In this embodiment, by making one of the short sides of the ring-shaped source electrode overlap the common electrode, a large additional capacitance can be formed without lowering the aperture ratio, and the voltage holding characteristics can be improved. In addition, since the horizontal common electrode is excluded from the light transmission region, it is advantageous for improving the pixel aperture ratio.

[Embodiment 4] FIG. 7 is a plan view of a unit pixel according to a fourth embodiment of the present invention. The sectional structure of this embodiment is the same as that of the first embodiment (FIG. 1). The present embodiment is characterized in that the source electrode 15 is formed in a ring shape as in the second embodiment, and the common electrode 16 is formed in a character shape. In this embodiment, by making the two short sides of the ring-shaped source electrode overlap the common electrode, a larger additional capacitance can be formed without lowering the aperture ratio, and the voltage holding characteristics can be improved.

[Embodiment 5] FIG. 8 is a plan view of a unit pixel according to a fifth embodiment of the present invention. The sectional structure of this embodiment is the same as that of the first embodiment (FIG. 1). In this embodiment, the common electrode 16 has a Π shape, and the source electrode 15 has a T shape. This embodiment is different from the second to fourth embodiments,
It is characterized in that a source electrode 15 is arranged at the center of a pixel, and a common electrode 16 is arranged on both left and right sides thereof. The advantage of such an arrangement is that the distance between the common electrode 16 and the drain electrode 14 can be reduced because the common electrode 16 and the drain electrode 14 are separated by the gate insulating film. Thereby, the common electrode 1
By bringing 6 closer to the drain electrode 14 as much as possible, the light transmission region can be enlarged and the aperture ratio can be improved. However, at this time, the common electrode 16 and the drain electrode 14
Overlap, the parasitic capacitance between these electrodes increases rapidly. Excessive parasitic capacitance between the common electrode and the drain electrode causes a waveform distortion of the common electrode signal, and causes image quality deterioration called smear, which is not desirable. Therefore, the common electrode and the drain electrode may be brought as close as possible but must never overlap.

[Embodiment 6] FIG. 9 is a plan view of a unit pixel according to a sixth embodiment of the present invention. The sectional structure of this embodiment is the same as that of the first embodiment (FIG. 1). The present embodiment is characterized in that the source electrode 15 is formed in a character shape and the common electrode 16 is formed in a ring shape. In the present embodiment, the aperture ratio can be improved as in the fifth embodiment,
Since the overlap between the source electrode 15 and the common electrode 16 can be increased, the additional capacitance can be increased.

[Embodiment 7] FIG. 10 is a plan view of a unit pixel according to a seventh embodiment of the present invention. The sectional structure of this embodiment is the same as that of the first embodiment (FIG. 1). In this embodiment,
The source electrode 15 has a ladder shape, and the common electrode 16 has a structure in which the common electrode 16 is overlapped with each other as a ring shape.
Unlike the sixth embodiment, the electric field for driving the liquid crystal is characterized in that it is in a direction parallel to the longitudinal direction of the pixel. In this embodiment, the gap between the common electrode 16 and the source electrode 15 can be arbitrarily changed by changing the number of ladder-shaped electrodes. Since the gap between the electrodes determines the response speed of the liquid crystal, a desired response speed can be obtained by arbitrarily adjusting the gap.

As described above, the common electrode and the source electrode
By forming the drain electrode in a different layer, a variety of electrode shapes can be designed, and display performance according to the application can be realized.

In the above embodiment, the case where the common electrode is formed of the same electrode material as the gate electrode has been described. However, the common electrode or the source electrode may be formed by combining a plurality of electrodes. Hereinafter, such an embodiment will be described.

[Embodiment 8] FIG. 11 is a plan view of a unit pixel according to an eighth embodiment of the present invention. FIG. 12 shows B- in FIG.
The sectional view at B 'is shown. In the present embodiment, the common electrode is composed of two members, namely, the extraction wiring 160 and the common-side drive electrode 161, and these are connected via the through hole TH provided in the gate insulating film 20. Here, the same electrode material as the gate electrode 10 was used for the lead wiring 160, and the same electrode material as the source electrode 15 was used for the common side drive electrode 161. Also in this embodiment, since the common electrode lead-out line 160 and the source electrode 15 are separated from each other by the gate insulating film 20, they can intersect with each other, and an additional capacitance can be formed at the intersection Cst to improve the holding characteristics. . Further, the common side drive electrode 161 is connected to the source electrode 1.
5, it is possible to shield an unnecessary electric field formed between the source electrode 15 and the adjacent drain electrode 14. The parasitic electric field formed by the electrodes that are not directly involved in driving the liquid crystal disturbs the orientation of the liquid crystal and causes the contrast of the displayed image to decrease,
Usually, the countermeasures are taken by hiding the periphery of the electrode with a light shielding layer. However, such a light-shielding layer has a drawback of lowering the aperture ratio. In contrast, as in this embodiment,
By shielding the parasitic electric field that disturbs the alignment of the liquid crystal, the area of the light shielding layer can be reduced, so that the aperture ratio can be improved.

Embodiment 9 FIG. 13 is a plan view of a unit pixel according to a ninth embodiment of the present invention. FIG. 14 shows C- in FIG.
The sectional view at C 'is shown. In this embodiment, the common electrode lead-out line 160 is made of the same electrode material as the gate electrode 10 as in the seventh embodiment, and the common side driving electrode 1
Numeral 61 is constituted by new electrodes provided on the protective insulating film 23, and these are connected by through holes. In the present embodiment, the common electrode is insulated and separated from the source electrode 15 for both the lead-out wiring 160 and the common-side drive electrode 161, so that the same effect as in the above-described embodiment is obtained.

[Embodiment 10] In the above embodiment, the common-side drive electrode 161 of the common electrode is constituted by an electrode provided on the protective insulating film 23. However, the common-side drive electrode may be provided below the gate electrode 10. . FIG. 15 shows a tenth embodiment of the present invention.
FIG. 4 is a plan view of a unit pixel according to the example. FIG. 16 is a sectional view taken along line DD 'in FIG. In this embodiment, the common electrode lead-out line 160 is made of the same electrode material as the gate electrode 10 as in the seventh embodiment, and the common-side drive electrode 161 is disposed below the gate electrode 10 with the insulating film 24 interposed therebetween. , And these were connected by through holes. In this embodiment, the common electrode is the source electrode 1 for both the extraction wiring 160 and the common-side drive electrode 161.
5, the same effect as in the above embodiment can be obtained.

[Embodiment 11] FIG. 17 is a plan view of a unit pixel according to an eleventh embodiment of the present invention. FIG. 18 shows E in FIG.
The sectional view at -E 'is shown. In this embodiment, the common electrode 16 is constituted by a new electrode provided below the gate electrode 10 with the base insulating film 24 interposed therebetween. Therefore, the common electrode has a different layer from the gate electrode 10, the source electrode 15, and the drain electrode 14. Therefore, in this embodiment, it is possible to draw out the common electrode 16 not only in the direction parallel to the gate electrode but also in the direction perpendicular to the gate electrode to form a mesh. As a result, the resistance value of the common electrode can be reduced, which has the effect of reducing the waveform distortion of the common voltage and preventing the occurrence of smear.

[Embodiment 12] FIG. 19 is a plan view of a unit pixel according to a twelfth embodiment of the present invention. FIG. 20 shows F in FIG.
The sectional view at -F 'is shown. In this embodiment, the common electrode 16 is constituted by a new electrode provided on the protective insulating film 23. Also in this embodiment, the common electrode is formed in a different layer from the gate electrode 10 and all of the source electrode 15 and the drain electrode 14 as in the eleventh embodiment. It can also be drawn out in a direction perpendicular to the gate electrode to form a mesh, which can reduce the waveform distortion of the common voltage and prevent the occurrence of smear.

Embodiment 13 FIG. 21 is a sectional view of a unit pixel according to a thirteenth embodiment of the present invention. The plan view of this embodiment is the same as that of the first embodiment. In this embodiment, the gate electrode 1
0 and the common electrode 16 are made of aluminum (Al), and the surface thereof is made of alumina (A) which is a self-oxidized film of Al.
1 ₂ O ₃ ) 21.
By employing such a two-layer insulating film structure, insulation defects between the common electrode 16 and the drain and source electrodes can be reduced, so that pixel defects can be reduced.

[Embodiment 14] FIG. 22 is a plan view of a unit pixel according to a fourteenth embodiment of the present invention. FIG. 23 shows G in FIG.
It is -G 'sectional drawing. In this embodiment, the common electrode 16 is made of tantalum (Ta), and its surface is covered with tantalum pentoxide (Ta ₂ O ₅ ) 22 which is a self-oxidized film of Ta. Another feature is that the gate insulating film 20 and the protective insulating film 23 on the side facing the source electrode 15 on the common electrode 16 are removed by etching. By exposing Ta ₂ O ₅ having a relative dielectric constant as large as 23, the electric flux can be concentrated on the source electrode side, so that the liquid crystal can be driven with a lower applied voltage.

FIG. 24 is a schematic plan view including an equivalent circuit of the active matrix substrate mirror of the present invention. On the glass substrate 1, a gate electrode 10 and a drain electrode 14, TFTs connected to them, a common electrode 16 drawn in parallel with the gate electrode 10, and gate electrodes 101, 151, 163 of the gate electrode, drain electrode and common electrode. It was formed. The extraction terminal is a terminal for supplying a signal to the gate electrode 10, the drain electrode 14, and the common electrode 16 from an external circuit.

FIG. 25 is a plan view of the pixel array of the active matrix section. In FIG. 25, the unit pixel shown in FIG. 9 is used. A plurality of pixels are arranged in the same direction as the direction in which the gate electrode 10 extends.
2, X3... Each pixel column X1,
Each pixel of X2, X3 ... is a thin film transistor TFT
1, the arrangement positions of the common electrode 16 and the source electrode 15 are the same. The drain electrode 14 is the gate electrode 1
The pixels are arranged so as to cross 0 and are connected to one pixel in each pixel column.

FIG. 26 is a sectional view of a cell of the liquid crystal display device of the present invention. A gate electrode (scanning signal electrode) 10 and a drain electrode (video signal electrode) 14 are formed on the lower glass substrate 1 in a matrix, and T is formed near the intersection thereof.
The source electrode 15 is driven via the FT. A color filter 507 and a color filter protective film 51 are formed on a counter substrate 508 that faces the liquid crystal layer including the rod-shaped liquid crystal molecules 513 therebetween.
1. A light-shielding black matrix 512 is formed. In FIG. 26, the center portion is a cross-sectional view of a unit pixel, the left side is a cross-sectional view of a portion where external connection terminals are present, and the right side is a cross-sectional view of a portion where no external connection terminals are present. The sealing material SL shown on the right and left sides of FIG. 26 is configured to seal the liquid crystal layer, and covers the entire edge of the glass substrate 1 and the opposite substrate (glass substrate) 508 except for the liquid crystal sealing port (not shown). It is formed along. The sealing material is formed of, for example, an epoxy resin. Each layer of the orientation control films ORI1, ORI2, the protective film 23, and the color filter protective film 511 is made of a sealing material S
It is formed inside L. The polarizing plate 505 is formed on the outer surfaces of the pair of glass substrates 1 and the opposite substrate (glass substrate) 508. The liquid crystal molecules 513 in the liquid crystal layer are aligned with the alignment control film O.
It is oriented in a predetermined direction by RI1 and ORI2, and a color image can be displayed by adjusting the light from the backlight BL by the liquid crystal layer in the portion between the source electrode 15 and the common electrode 16.

[0042]

As described above, according to the present invention, the extraction wiring of the common electrode (common electrode) and the video signal electrode (source electrode) and the pixel electrode (drain electrode) are formed in different layers by the insulating film. A liquid crystal can be driven by generating an electric field parallel to the substrate surface without using a comb-shaped electrode, realizing a bright active matrix type liquid crystal display device with a high production yield and a large pixel aperture ratio. it can.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a pixel when no electric field is applied in a first embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a schematic sectional view of a pixel when no electric field is applied in the first embodiment of the liquid crystal display device according to the present invention.

FIG. 3 is a schematic plan view of a pixel when an electric field is applied in the first embodiment of the liquid crystal display device according to the present invention.

FIG. 4 is a schematic sectional view of a pixel when an electric field is applied in the first embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a plan view of a pixel when no electric field is applied in a second embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is a plan view of a pixel in the third embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 7 is a pixel plan view of the fourth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 8 is a pixel plan view of the fifth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 9 is a pixel plan view of the sixth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 10 is a plan view of a pixel in the seventh embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 11 is a plan view of a pixel when an electric field is not applied in an eighth embodiment of the liquid crystal display device according to the present invention.

FIG. 12 is a sectional view of a pixel of the eighth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 13 is a pixel plan view of the ninth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 14 is a pixel sectional view of the ninth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 15 is a pixel plan view of the tenth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 16 is a pixel cross-sectional view of the tenth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 17 is a plan view of a pixel when an electric field is not applied in an eleventh embodiment of the liquid crystal display device according to the present invention.

FIG. 18 is a sectional view of a pixel of the eleventh embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 19 is a plan view of a pixel of the twelfth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 20 is a pixel cross-sectional view of the twelfth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 21 is a sectional view of a pixel in a thirteenth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 22 is a pixel plan view of the fourteenth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 23 is a pixel cross-sectional view of the fourteenth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

FIG. 24 is a plan view showing an equivalent circuit of the liquid crystal display device according to the present invention.

FIG. 25 is a plan view of a display section TFT matrix section of the liquid crystal display device according to the present invention.

FIG. 26 is a sectional view of a cell of the liquid crystal display device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 10 ... Gate electrode, 14 ... Drain electrode, 15 ... Source electrode, 16 ... Common electrode, 20 ... Gate insulating film, 21 ... Alumina film, 22 ... Tantalum pentoxide film, 23 ... Protective insulating film, 24 ... Underlying insulating film, 30... Amorphous silicon film, 101...
... Leader terminal of drain electrode, 160… leader wiring of common electrode, 161… drive electrode on common side, 505… polarizing plate, 5
07: color filter, 508: counter substrate, 511: color filter protective film, 512: black matrix for light shielding, 513: liquid crystal molecules, ORI1, ORI2: alignment control film, SL: sealing material, C1, C2, C3, C4 Cs
t: additional capacitance, TH: through hole, E1: liquid crystal driving electric field.

Claims (9)

[Claims] 1. A liquid crystal display device comprising: a pair of substrates; and a liquid crystal layer sandwiched between the pair of substrates. One of the pair of substrates has a plurality of scanning signal electrodes and intersects them in a matrix. What is claimed is: 1. A liquid crystal display device comprising: a plurality of video signal electrodes; and a plurality of thin film transistors formed corresponding to intersections of these electrodes, wherein the liquid crystal display device is surrounded by the plurality of scanning signal electrodes and the plurality of video signal electrodes. A pixel having a common electrode and a pixel electrode connected to a thin film transistor is formed in each region, and the common electrode extends in a direction substantially equal to a direction in which the video signal electrode extends, and a pixel extending in a direction substantially parallel to the scanning signal electrode. A lead wire for connecting to a common electrode of a pixel adjacent in the direction, wherein the pixel electrode has a portion extending in a direction substantially equal to a direction in which the video signal electrode extends; The portion of the elementary electrode extending in the direction substantially equal to the direction in which the video signal electrode extends and the portion of the common electrode extending in the direction substantially equal to the direction in which the video signal electrode extends are above the common electrode lead-out wiring. A liquid crystal display device formed on a liquid crystal display. 2. The device according to claim 1, wherein a portion of said common electrode extending in a direction substantially equal to a direction in which said video signal electrode extends is connected to a lead wire of said common electrode via a through hole. Liquid crystal display device. 3. The liquid crystal display device according to claim 1, wherein the lead wire of the common electrode is formed in the same layer as the scanning signal electrode. 4. The device according to claim 1, wherein a portion of the common electrode extending in a direction perpendicular to the scanning signal electrode is formed in the same layer as a portion of the corresponding pixel electrode extending in a direction perpendicular to the scanning signal electrode. A liquid crystal display device characterized in that: 5. The liquid crystal display device according to claim 4, wherein a portion of the common electrode extending in a direction substantially equal to a direction in which the video signal electrode extends is formed in the same layer as the video signal electrode. 6. The liquid crystal display device according to claim 1, wherein at least a part of a portion of the common electrode extending in a direction substantially equal to a direction in which the video signal electrode extends is in contact with the liquid crystal layer. 7. The method according to claim 1, wherein
A liquid crystal display device, wherein at least a part of the common electrode is constituted by a metal electrode whose surface is covered with a self-oxidizing film or a self-nitriding film. 8. The method according to claim 1, wherein
A liquid crystal display device, wherein a part of a lead electrode of the common electrode and a corresponding pixel electrode are overlapped with each other via an insulating film, and an additional capacitance is formed in the overlapped portion. 9. A semiconductor device comprising: a pair of substrates; and a liquid crystal layer sandwiched between the pair of substrates. One of the pair of substrates has a plurality of scanning signal electrodes and intersects them in a matrix. What is claimed is: 1. A liquid crystal display device comprising: a plurality of video signal electrodes; and a plurality of thin film transistors formed corresponding to respective intersections of these electrodes, wherein the liquid crystal display device is surrounded by the plurality of scanning signal electrodes and the plurality of video signal electrodes. A pixel having a common electrode and a pixel electrode connected to the thin film transistor is formed in each region, and the common electrode has a portion extending in a direction substantially equal to a direction in which the video signal electrode of the common electrode extends, and a scanning signal. A lead wire for connecting to a common electrode of a pixel adjacent in a direction parallel to the electrode, wherein the pixel electrode has a portion extending in a direction perpendicular to a scanning signal electrode of the common electrode. The lead-out wiring of the common electrode is formed in the same layer as the scanning signal electrode, and a portion of the common electrode extending in a direction substantially equal to a direction in which the video signal electrode extends is a video signal electrode and a pixel electrode. In the same layer as the portion extending in the direction substantially equal to the direction in which the video signal electrode extends, the lead wiring of the common electrode is formed in a different layer via an insulating film, and the lead wiring of the common electrode and A liquid crystal display device wherein a portion of the common electrode extending in a direction substantially equal to a direction in which the video signal electrode extends is connected via a through hole.