JPH095793A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an opening rate and brightness by adjacently arranging plural common electrodes so as to hold corresponding video signal electrodes between adjacent pixels and generating the electric fields parallel with substrates by the voltage impressed on the common electrodes and pixel electrodes. SOLUTION: Gate insulating films 20 are formed so as to cover gate electrode (scanning signal electrodes) 10 and common electrodes 16 formed on a glass substrate 1. Drain electrodes (video signal electrodes) 14 and source electrodes (pixel electrodes) 15 to be superposed on part of the patterns of amorphous silicon films 30 formed via the insulting films 20 on the gate electrodes 10 are formed and are coated with protective insulating films 23. Such unit pixels are arranged in a matrix form and the surface of an oriented film ORI1 formed on the surface is subjected to a rubbing treatment and a liquid crystal compsn. contg. bar-shaped liquid crystal molecules 513 is enclosed between the above substrate and a counter substrate 508. An electric field E1 parallel with the substrate 1 is induced between the source electrodes 15 and the common electrodes 16 and the direction of the liquid crystal molecules 513 is changed in the direction of this electric field when the voltage is impressed on the gate electrodes 10.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an image of an OA device,
The present invention relates to the 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) in which thin film transistors (hereinafter referred to as TFTs) are formed in a matrix on an insulating substrate such as glass and used as switching elements is a flat panel of high image quality. Expectations are high as a display. In the conventional active matrix type liquid crystal display device, transparent electrodes formed on two substrates and facing each other are used as electrodes for driving the liquid crystal layer. This is because a display system typified 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 is adopted.

On the other hand, as a method for making the direction of the electric field applied to the liquid crystal substantially parallel to the substrate surface, a method using comb-teeth electrodes is disclosed in Japanese Patent Publication No. 63-21907.

[0004]

In the above-mentioned prior art, the liquid crystal layer is driven by the comb-teeth-shaped electrodes that interlock with each other. However, since the comb-teeth-shaped electrodes are used as the drive electrodes, light can be transmitted. 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
Although the aperture ratio can be increased to a practical level by reducing it to about 2 μm, it is actually extremely difficult to form such fine lines uniformly over the entire surface of a large-sized substrate without any breakage. That is, in the above-described conventional technique, since the comb-teeth-shaped electrodes that interlock with each other are used, there is a trade-off relationship between the pixel aperture ratio and the manufacturing yield, and it is difficult to provide a liquid crystal display device having a bright image at low cost. Met.

The present invention solves the above problems, and an object thereof is to provide a bright liquid crystal display device having a higher manufacturing yield and a higher aperture ratio.

[0006]

According to the present invention, a plurality of scanning signal electrodes and a plurality of video signal electrodes intersecting them in a matrix are provided on one substrate of a pair of substrates of a liquid crystal display device. It has a plurality of thin film transistors formed corresponding to respective intersections of these electrodes.

At least one pixel is formed in each region surrounded by the plurality of scanning signal electrodes and the video signal electrodes, and each pixel includes a plurality of common electrodes connected by a connecting portion over the plurality of pixels. , And at least one pixel electrode arranged between these common electrodes and connected to the corresponding thin film transistor.

The plurality of common electrodes are arranged adjacent to each other so as to sandwich the corresponding video signal electrode between adjacent pixels, and an electric field parallel to the substrate is generated in the liquid crystal layer by the voltage applied to the common electrode and the pixel electrode. appear.

Preferably, an insulating layer is formed on the common electrode, and a plurality of video signal electrodes are formed on this insulating layer.
Further, the common electrode and the scanning signal electrode are formed in the same layer. A part of the pixel electrode may be overlapped on the connection part of the common electrode via an insulating layer, and the overlapped part may form an additional capacitance.

According to an embodiment, the common electrode has its surface coated with a self-oxidizing film or a self-nitriding film.

Further, the shape of the pixel electrode or the common electrode is
The shape may be any one of a ring shape, a cross shape, a T shape, a Π shape, a work shape, and a ladder shape.

According to the present invention, by arranging the common electrodes so as to be adjacent to each other so as to sandwich the video signal electrode, it is possible to increase the aperture ratio (the area ratio of the openings through which light is transmitted). Further, the pixel aperture ratio can be further increased and the voltage holding characteristic can be improved by forming at least a part of the pixel electrode and the common electrode on each other through the insulating film to form the additional capacitance.

Further, by making the common electrode and the video signal electrode different from each other or the common electrode and the pixel electrode different from each other by an insulating film, it is possible to reduce the probability of occurrence of a short circuit defect between these electrodes, thereby reducing pixel defects. it can.

The shape of the common electrode or the pixel electrode is as follows.
It is desirable to adopt a pattern that maximizes the aperture ratio. Therefore, the pixel electrode or the common electrode is
It is easy to design an electrode shape that maximizes the aperture ratio by using any one of a ring shape, a cross shape, a T shape, a Π shape, a work shape shape, and a ladder shape.

Further, by forming the common electrode by a metal electrode whose surface is covered with a self-oxidizing film or a self-nitriding film, when the common electrode and the pixel electrode are overlapped with each other, a short circuit between them may not occur. Since it can be prevented, pixel defects can be reduced.

[0016]

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 the operating principle of the first embodiment of the present invention. A gate electrode 10 and a common electrode (common electrode) 16 made of Cr 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 (scanning signal electrode) 10 via the gate insulating film 20 to serve as an active layer of the transistor. The a-S
A drain electrode (video signal electrode) 14 and a source electrode (pixel electrode) 15 made of Mo are formed so as to overlap a part of the pattern of the i film 30, and a protective insulating film made of a SiN film so as to cover all of them. 23 was formed. An alignment film OR made of polyimide is formed on the surface of an active matrix substrate having unit pixels arranged in a matrix.
I1 and ORI2 were formed, and the surface was rubbed. Alignment films ORI1 and OR which have been similarly rubbed
A liquid crystal composition containing rod-shaped liquid crystal molecules 513 is enclosed between the counter substrate 508 having I2 formed on the surface and the active matrix substrate, and the polarizing plate 50 is provided on the outer surfaces of the two substrates.
5 was arranged. When there is no electric field (FIGS. 1 and 2), the liquid crystal molecules 513 have a slight angle with respect to the longitudinal direction of the stripe-shaped source electrode 15 and the common electrode 16, that is, the major axis (optical axis) of the liquid crystal molecules and the direction of the electric field. The angle formed by (perpendicular to the longitudinal direction of the source electrode and the common electrode) is 45 ° or more 90
Oriented to have less than °. The alignment of the liquid crystal molecules at the interface with the upper and lower substrates was parallel to each other. Moreover, 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 an electric field E1 is induced between the source electrode 15 and the common electrode 16. As shown, the liquid crystal molecules turn in the direction of the electric field. By arranging the polarization transmission axes of the two polarizing plates 505 arranged on the surfaces of the upper and lower substrates at a predetermined angle AGL1, it becomes possible to change the light transmittance by applying an electric field. in this way,
With the display system of the present invention, it is possible to provide a display that gives contrast without the need for a transparent electrode, which has been conventionally required. For this reason, it is possible to omit all the steps related to the formation of the transparent electrode, so that the manufacturing cost can be reduced. Further, in the conventional display method using a transparent electrode, the dark state is obtained by raising the major axis of liquid crystal molecules from the substrate interface by applying a voltage and setting the birefringence phase difference to 0, but the birefringence phase difference is 0. The viewing angle direction is only the front direction, that is, the direction perpendicular to the substrate interface, and if it is tilted even slightly, a sub-refraction phase difference appears, and light leaks in a normally open type display, which lowers the contrast and inverts the gradation level. . However, in the display system of the present embodiment, the long axis of the liquid crystal molecules is almost parallel to the substrate and does not rise even when a voltage is applied. Therefore, the change in brightness when the viewing angle direction is changed is small and the viewing angle characteristics are large. Has the effect of being improved.

Further, in this embodiment, the common electrode 16 is formed in the same layer as the gate electrode 10, and the drain electrode 14, the source electrode 15 which is a liquid crystal driving electrode, and the common electrode 16 are insulated and separated by the gate insulating film 20. Further, the comb-teeth-shaped electrode which has been conventionally used is abolished, and the source electrode 15 and the common electrode 16 are superposed with the gate insulating film 20 interposed therebetween. By insulating the drain electrode 14 and the source electrode 15 from the common electrode 16 in this manner, the degree of freedom in designing the plane 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-teeth-shaped electrode, and is achieved only by insulating the drain electrode 14 and the source electrode 15 from the common electrode 16. 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 the plane pattern is increased. Therefore, the electrode shape is not limited to this embodiment, and various structures are possible. 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, while the source electrode 15 has a ring shape. The common electrode 16 and the source electrode 15 are overlapped with each other at the portions marked C1, C2, C3 and C4 to form an additional capacitance. According to this embodiment, the distance between the common electrode 16 and the gate electrode 10 can be made large, so that a short circuit failure between the common electrode 16 and the gate electrode 10 can be prevented. Further, by making the source electrode 15 a ring type, even if a disconnection occurs at any place of the source electrode,
Unless there is a break in more than one place, power is supplied to the entire source electrode and normal operation is possible. That is, this 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). The present embodiment is characterized in that the source electrode 15 is ring-shaped and the common electrode 16 is T-shaped as in the second embodiment. In this embodiment, one of the short sides of the ring-shaped source electrode is overlapped with the common electrode, so that a large additional capacitance can be formed without lowering the aperture ratio and the voltage holding characteristic can be improved. Further, the common electrode in the horizontal direction is excluded from the light transmitting region, which 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 of a ring type and the common electrode 16 is of a letter-shaped type as in the second embodiment. In this embodiment, by making the two short sides of the ring-shaped source electrode and the common electrode overlap, a larger additional capacitance can be formed without lowering the aperture ratio, and the voltage holding characteristic 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. The present embodiment is different from the second to fourth embodiments in that the source electrode 15 is arranged at the center of the pixel and the common electrodes 16 are arranged on the left and right sides thereof. The advantage of such an arrangement is that the common electrode 16 and the drain electrode 14 are separated by the gate insulating film, so that the distance between these electrodes can be reduced. As a result, the light transmitting region can be expanded and the aperture ratio can be improved by bringing the common electrode 16 close to the drain electrode 14. However, at this time, the common electrode 16 and the drain electrode 1
When 4 overlap, the parasitic capacitance between these electrodes increases rapidly. An excessive parasitic capacitance between the common electrode and the drain electrode causes waveform distortion of the common electrode signal, which causes deterioration of image quality called smear, which is not desirable. Therefore,
The common electrode and the drain electrode may be brought as close as possible, but it is necessary that they 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 has a letter-letter shape and the common electrode 16 has a ring shape. In this embodiment, in addition to being able to improve the aperture ratio 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 is a ladder type, and the common electrode 16 is a ring type and has a structure in which they are stacked on each other.
Unlike the sixth embodiment, it is characterized in that the electric field for driving the liquid crystal is in the direction parallel to the longitudinal direction of the pixel. In the present embodiment, the gap between the common electrode 16 and the source electrode 15 can be arbitrarily changed by changing the number of ladder electrodes. Since the gap between the electrodes determines the response speed of the liquid crystal, it is possible to obtain a desired response speed by adjusting the gap arbitrarily.

As described above, the common electrode and the source electrode,
By forming the drain electrode in different layers, it is possible to design a wide variety of electrode shapes, and display performance according to the application can be realized.

In the above embodiments, the common electrode is made of the same electrode material as the gate electrode, but the common electrode or the source electrode may be made of a combination of a plurality of electrodes. Hereinafter, such an example is shown.

[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 in B'is shown. In this embodiment, the common electrode is composed of two members, that is, the lead-out wiring 160 and the common-side drive electrode 161, which are connected via the through hole TH provided in the gate insulating film 20. Here, the same electrode material as that of the gate electrode 10 was used for the lead-out wiring 160, and the same electrode material as that of the source electrode 15 was used for the common side drive electrode 161. Also in the present embodiment, since the common electrode lead-out wiring 160 and the source electrode 15 are made different layers by the gate insulating film 20, they can be crossed with each other and an additional capacitance can be formed at the crossing portion Cst to improve the retention characteristic. . In addition, the common side drive electrode 161 is connected to the source electrode 1
By forming it in the same layer as 5, the unnecessary electric field formed between the source electrode 15 and the adjacent drain electrode 14 can be shielded. Since the parasitic electric field formed by the electrodes that are not directly involved in driving the liquid crystal disturbs the alignment of the liquid crystal and causes a reduction in the contrast of the displayed image,
A measure is usually taken by hiding the periphery of the electrode with a light shielding layer. However, such a light-shielding layer has a drawback of reducing the aperture ratio. On the other hand, as in the present embodiment, the area of the light shielding layer can be reduced by shielding the parasitic electric field that disturbs the alignment of the liquid crystal, 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 in C'is shown. In this embodiment, the common electrode lead wiring 160 is made of the same electrode material as the gate electrode 10 as in the seventh embodiment, and the common side drive electrode 1
Reference numeral 61 is composed of a new electrode provided on the protective insulating film 23, and these are connected by a through hole. In this embodiment, since the common electrode is insulated from the source electrode 15 in both the extraction wiring 160 and the common side drive electrode 161, the same effect as the above embodiment can be obtained.

[Embodiment 10] In the above embodiment, the common side drive electrode 161 of the common electrode is constituted by the electrode provided on the protective insulating film 23, but the common side drive electrode may be provided in the lower layer of the gate electrode 10. . FIG. 15 shows the tenth aspect of the present invention.
3 is a plan view of a unit pixel of the example of FIG. FIG. 16 is a sectional view taken along the line DD ′ in FIG. In this embodiment, the common electrode lead-out wiring 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 provided below the gate electrode 10 with the insulating film 24 interposed therebetween. It was constructed by new electrodes provided by the above, and these were connected by through holes. In this embodiment, the common electrode is the lead wire 160 and the common side drive electrode 161 is the source electrode 1
Since it is electrically isolated from No. 5, it has the same effect as the above-mentioned embodiment.

[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.
-E 'shows a cross-sectional view. In this embodiment, the common electrode 16 is composed of a new electrode provided below the gate electrode 10 with the underlying insulating film 24 interposed therebetween. Therefore, the common electrode is formed in a different layer from all of the gate electrode 10, the source electrode 15, and the drain electrode 14. Therefore, in this embodiment, the common electrode 16 can be drawn not only in the direction parallel to the gate electrode but also in the direction perpendicular to the gate electrode to form a mesh shape. As a result, the resistance value of the common electrode can be lowered, so that the waveform distortion of the common voltage can be reduced and the smear can be prevented.

[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.
A sectional view at -F 'is shown. In this embodiment, the common electrode 16 is composed of a new electrode provided on the protective insulating film 23. Also in this embodiment, the common electrode is formed in a different layer from all of the gate electrode 10, the source electrode 15, and the drain electrode 14 in the same manner as in the eleventh embodiment, so that the common electrode 16 is not limited to the direction parallel to the gate electrode. It is also possible to draw out in a direction perpendicular to the gate electrode to form a mesh shape, 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 similar to 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
It is characterized in that it is covered with 1 ₂ O ₃ ) 21.
By adopting such a two-layer insulating film structure, it is possible to reduce defective insulation between the common electrode 16 and the drain and source electrodes, and thus it is possible to reduce pixel defects.

[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 of FIG.
It is a -G 'sectional view. In this embodiment, the common electrode 16 is made of tantalum (Ta), and the surface of the common electrode 16 is covered with tantalum pentoxide (Ta ₂ O ₅ ) 22 which is a self-oxidation 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 large relative permittivity of 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, a TFT connected to them, a common electrode 16 extended in parallel to the gate electrode 10, a gate electrode drain electrode, and extraction terminals 101, 151, 163 of the common electrode are formed. It was done. Lead-out terminals are gate electrode 10 and drain electrode 1
4 and the common electrode 16 are terminals for supplying a signal from an external circuit.

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

FIG. 26 is a cell sectional view of the liquid crystal display device of the present invention. The gate electrode 10 and the drain electrode 14 are formed in a matrix on the lower glass substrate 1, and the source electrode 15 is driven through the TFT formed near the intersection. A color filter 507, a color filter protective film 511, and a light-shielding black matrix 512 are formed on a counter substrate 508 which faces the liquid crystal layer including rod-shaped liquid crystal molecules 513. The central part of FIG. 26 is a sectional view of a unit pixel, the left side is a sectional view of a portion where external connection terminals are present, and the right side is a sectional view of a portion where external connection terminals are not present. The sealing material SL shown on the right side and the left side of FIG. 26 is configured to seal the liquid crystal layer, and is formed along the entire edges of the glass substrates 1 and 508 excluding the liquid crystal sealing port (not shown). . The sealing material is made of, for example, an epoxy resin. The orientation control films ORI1, ORI2, the protective insulating film 23, and the color filter protective film 511 are formed inside the sealing material SL. The polarizing plate 505 is formed on the outer surface of the pair of glass substrates 1 and 508. The liquid crystal molecules 513 in the liquid crystal layer are aligned in a predetermined direction by the alignment control films ORI1 and ORI2, and the light from the backlight BL is adjusted by the liquid crystal layer between the source electrode 15 and the common electrode 16. A color image can be displayed.

[0036]

As described above, according to the present invention, a liquid crystal display device having a high aperture ratio is realized by arranging a plurality of common electrodes so as to sandwich a corresponding video signal electrode between adjacent pixels. it can.

[Brief description of drawings]

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

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

FIG. 3 is a schematic plan view of a pixel when an electric field is applied to the liquid crystal display device according to the first embodiment of 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 pixel plan view of the second embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

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

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

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

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

FIG. 11 is a plan 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. 12 is a cross-sectional view of pixels of an eighth embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

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

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

FIG. 17 is a pixel plan view of the eleventh embodiment of the liquid crystal display device according to the present invention when no electric field is applied.

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

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

FIG. 21 is a pixel cross-sectional view of a liquid crystal display device according to a thirteenth embodiment of 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 a fourteenth embodiment of a 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 TFT matrix portion of the liquid crystal display device according to the present invention.

FIG. 26 is a cell cross-sectional view of a 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 ... Base insulating film, 30 ... Amorphous silicon film, 101 ... Gate electrode lead terminal, 14
DESCRIPTION OF SYMBOLS 1 ... Lead-out terminal of drain electrode, 160 ... Lead-out wiring of common electrode, 161 ... Common side drive electrode, 505 ... Polarizing plate, 507 ... Color filter, 508 ... Counter substrate, 51
1 ... Color filter protective film, 512 ... Black matrix for shading, 513 ... Liquid crystal molecules, ORI1, ORI2 ...
Alignment film, SL ... Sealing material, C1, C2, C3, C4, C
st ... additional capacitance, TH ... through hole, E1 ... liquid crystal driving electric field.

Claims (12)

[Claims] 1. A liquid crystal display device comprising a pair of substrates and a liquid crystal layer sandwiched between the pair of substrates, wherein one of the pair of substrates has a plurality of scanning signal electrodes and a matrix of scanning signal electrodes formed thereon. A plurality of video signal electrodes intersecting with each other, and a plurality of thin film transistors formed corresponding to the respective intersections of these electrodes, at least in each region surrounded by the plurality of scanning signal electrodes and video signal electrodes One pixel is configured, and each pixel includes a plurality of common electrodes connected by a connecting portion across the plurality of pixels and at least one common electrode arranged between these common electrodes and connected to a corresponding thin film transistor. A pixel electrode, the plurality of common electrodes are arranged adjacent to each other so as to sandwich a corresponding video signal electrode between adjacent pixels, and the common electrode and the pixel electrode are connected to each other. The voltage to be pressurized, wherein the liquid crystal layer liquid crystal display device characterized by parallel electric field is generated in the substrate. 2. The liquid crystal according to claim 1, wherein the plurality of video signal electrodes and the plurality of common electrodes adjacent to the video signal electrodes are formed through an insulating layer. Display device. 3. The liquid crystal display device according to claim 2, wherein the insulating layer is formed on the plurality of common electrodes. 4. The liquid crystal display device according to claim 3, wherein the plurality of video signal electrodes are formed on the insulating layer. 5. A liquid crystal display device according to claim 1, wherein the plurality of common electrodes and the plurality of scanning signal electrodes are formed in the same layer. 6. The liquid crystal display device according to claim 5, wherein the insulating layer is formed on the plurality of scanning signal electrodes. 7. The at least one pixel electrode according to claim 1, wherein a part of the at least one pixel electrode is superposed on the connection of the plurality of common electrodes via an insulating layer, and the superposed part forms an additional capacitance. And a liquid crystal display device. 8. The liquid crystal display device according to claim 7, wherein the insulating layer is formed on the plurality of common electrodes. 9. The method according to claim 7, wherein the plurality of common electrodes and the plurality of scanning signal electrodes are formed in the same layer, and the insulating layer is formed on the scanning signal electrodes. Liquid crystal display device. 10. The liquid crystal display device according to claim 8 or 9, wherein the at least one pixel electrode is formed on the insulating layer. 11. The liquid crystal display device according to claim 10, wherein the plurality of video signal electrodes are formed on the insulating layer. 12. The liquid crystal display device according to claim 1, wherein a surface of each of the plurality of common electrodes is covered with a self-oxidation film or a self-nitridation film.