JPH09230378A - Liquid crystal display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a liquid crystal display device capable of realizing highly bright display or reducing power consumption by extending a display electrode in the first direction in a display area, extending counter electrodes and a source signal wiring in the first direction, and shraddling them over display areas. SOLUTION: A plurality of display areas 2a put with display electrodes 2 and counter wirings 1 between are provide in a matrix state in an active matrix substrate 100. A gate signal wiring 3 and a source signal wiring 4 are provided through the circumference of a display area 2. The counter wiring 1 is formed in a stripe state on a insulation film between layers, and the counter wiring 1 and display electrode 2 are arranged so as to be made in parallel to each other in the longitudinal direction. The counter wiring 1 forms the peripheral part of a display area 2a, and arranged at the position where it is not superimpose with be adjacent source signal wiring 4. Further, the counter wiring 1 forms a extended stripe shape while straddling adjacent plural display areas 2a in the longitudinal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a switching element such as a thin film transistor (hereinafter referred to as TFT) and using liquid crystal or the like as a display medium, and more particularly to a structure of an active matrix substrate.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device in which TFTs are formed in a matrix on an insulating substrate such as glass and used as a switching element is expected to realize a high quality flat panel display. There is. As an effective means for achieving a wide viewing angle in a conventional active matrix type liquid crystal display device, a method of applying an electric field to a liquid crystal in a direction substantially parallel to the substrate has been proposed (for example, Japanese Patent Laid-Open No. 7-36058). Issue).

FIGS. 11A, 11B and 12 show such a conventional active matrix type liquid crystal display device 40.
0 is shown. 11A and 11B show a portion corresponding to one pixel in the active matrix substrate 401, and FIG. 12 shows a line A shown in FIG.
-A ′ active matrix liquid crystal display device 4
00 shows a cross section.

As shown in FIG. 12, an active matrix type liquid crystal display device 400 comprises an active matrix substrate 401, a counter substrate 402, and a liquid crystal layer 17 sandwiched between both substrates. The active matrix substrate 401 includes a glass substrate 100, a gate signal line 102 formed on the glass substrate 100, a common wiring 123, a gate insulating film 103, a source signal line 108, and a semiconductor layer 10.
4, a pixel electrode 111, and a drive electrode 113. The gate insulating film 103 is formed so as to cover the gate signal wiring 102 and the common wiring 123, and the semiconductor layer 104, the source signal wiring 108, the pixel electrode 111, and
And the drive electrode 113 is formed.

As shown in FIGS. 11A and 11B, the source signal line 108 has a branch 108 'at a portion where the source signal line 108 intersects with the gate signal line 102. A switching element (TFT) 403 is configured by using 102 as the gate electrode 105, the branch portion 108 ′ as the source electrode, and the pixel electrode 111 as the drain electrode. The drive electrode 113 is formed of the same material as the pixel electrode 111. The drive electrode 13 has a through hole 2
00 to the common wiring 123.

A protective insulating film 124 is formed so as to cover the source signal line 108, the pixel electrode 111, the drive electrode 113, and the switching element 403, and the alignment film 1 is formed thereon.
16 are formed. The common line 23 and the pixel electrode 11 intersect with each other through the gate insulating film 3, and an additional capacitance is formed at this intersection.

The counter substrate 402 includes the substrate 114 and the substrate 1.
14 includes an alignment film 116 formed on the active matrix substrate 401 side and a deflecting plate 112 formed on the outside.

In such an active matrix type liquid crystal display device 400, the liquid crystal layer 117 is driven by an electric field formed in a direction substantially parallel to the substrate surface (horizontal electric field driving method). As shown in FIG. 11A, in the state where no voltage is applied, the liquid crystal molecules 25 are
1 and the drive electrode 113 are oriented so as to form a slight angle (0 degree or more and less than 15 degrees) with respect to the longitudinal direction. When a voltage is applied between the picture element electrode 111 and the drive electrode 113, the liquid crystal molecules 25 are aligned along the electric field E directed from the picture element electrode 111 to the drive electrode 113, as shown in FIG.

[0009]

In the horizontal electric field driving type liquid crystal display device 400 as described above, the common wiring 1 is used.
23 and its driving electrode 113 are arranged on the TFT substrate side, the active matrix substrate side is compared to the conventional vertical electric field driving type liquid crystal display device in which the common wiring (driving electrode) is arranged on the counter substrate side. The wiring structure of the electrode becomes complicated. Therefore, there is a problem that crosstalk easily occurs due to the parasitic capacitance between the wirings. Further, in the case of a transmissive liquid crystal display device, sufficient brightness cannot be obtained because the area of the opening through which the backlight light is transmitted is narrowed due to the presence of the common wiring and the drive electrode.

The present invention has been made in view of the above problems, and it is an object of the present invention to (1) display a high-luminance display by increasing the area of an opening through which backlight light passes. Provided is a liquid crystal display device which can realize low power consumption, and (2) provides a liquid crystal display device which realizes high-quality display with reduced crosstalk by suppressing the influence of a source signal line on a pixel electrode. Especially.

[0011]

A liquid crystal display device according to the present invention includes a substrate, a gate signal wiring and a gate insulating film provided on the substrate, and a source signal wiring provided on the gate insulating film. A thin film transistor provided on the gate insulating film and formed at each intersection of the gate signal wiring and the source signal wiring, a drain electrode connected to the thin film transistor, and a connection electrode connected to the drain electrode. A common wiring for forming a storage capacitor through a part of the connection electrode and the gate insulating film, an interlayer insulating film formed on the gate insulating film, and a liquid crystal provided on the interlayer insulating film. An active matrix substrate having a drive display electrode and a counter electrode, a counter substrate facing the active matrix substrate, and a sandwiched between the active matrix substrate and the counter substrate. A liquid crystal layer, and the display electrode extends in a first direction in a display area, and the counter electrode and the source signal wiring are in the first direction in the display area. In the direction and across a plurality of the display areas, whereby the above-mentioned object is achieved.

In one embodiment, at least one of the display electrode and the counter electrode is formed so as to overlap with the source signal line.

In another embodiment, at least one of the display electrode and the counter electrode is formed so as to overlap with the gate signal wiring.

A liquid crystal display device according to the present invention includes a substrate, a gate signal wiring and a gate insulating film provided on the substrate,
A source signal wiring provided on the gate insulating film, a thin film transistor provided on the gate insulating film, formed at each intersection of the gate signal wiring and the source signal wiring, and connected to the thin film transistor. A drain electrode,
A connection electrode connected to the drain electrode, a common wiring for forming a storage capacitor via a part of the connection electrode and the gate insulating film, and an interlayer insulating film formed on the gate insulating film, An active matrix substrate having a liquid crystal driving display electrode and a counter electrode provided on the interlayer insulating film, a counter substrate facing the active matrix substrate, and the active matrix substrate and the counter substrate sandwiched between the active matrix substrate and the counter substrate. A liquid crystal display device including a liquid crystal layer, wherein the counter electrode is directly connected to the common wiring through a contact hole provided in the interlayer insulating layer, whereby the above object is achieved. It

The liquid crystal display device of the present invention comprises a substrate, a gate signal line and a gate insulating film provided on the substrate,
A source signal wiring provided on the gate insulating film, a thin film transistor provided on the gate insulating film, formed at each intersection of the gate signal wiring and the source signal wiring, and connected to the thin film transistor. A drain electrode,
A connection electrode connected to the drain electrode, a common wiring for forming a storage capacitor via a part of the connection electrode and the gate insulating film, and an interlayer insulating film formed on the gate insulating film, An active matrix substrate having a liquid crystal driving display electrode and a counter electrode provided on the interlayer insulating film, a counter substrate facing the active matrix substrate, and the active matrix substrate and the counter substrate sandwiched between the active matrix substrate and the counter substrate. Facing the liquid crystal layer and the active matrix substrate,
The liquid crystal display device includes a counter substrate having a liquid crystal driving counter electrode, a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, and thereby the above object is achieved.

In one embodiment, the display electrode is formed so as to overlap the source signal line or the gate signal line.

In another embodiment, the longitudinal direction of the counter electrode has a constant angle with respect to the longitudinal direction of the display electrode.

Further, in another embodiment, the thickness of the interlayer insulating layer is 1.0 to 10.0 μm.

Further, in another embodiment, the value of the dielectric constant of the interlayer insulating layer is 1.5 to 3.5. Further, in another embodiment, the material of the interlayer insulating film is an organic resin.

Further, in another embodiment, image display is performed by driving the liquid crystal layer molecules in the display area to rotate in a direction substantially horizontal to the substrate surface.

A method of manufacturing a liquid crystal display device according to the present invention comprises a step of forming a gate electrode and a common wiring on a substrate, and a gate insulating layer formed on the substrate so as to cover the gate electrode and the common wiring. A step of forming a gate signal wiring, a source signal wiring and a connection electrode on the gate insulating layer, a step of forming a thin film transistor at the intersection of the gate signal wiring and the source signal wiring, A step of forming an interlayer insulating film on the gate insulating layer so as to cover the thin film transistor, the connection electrode, the source signal wiring, the gate signal wiring and the common wiring; and a liquid crystal driving display electrode on the interlayer insulating film. And a step of forming a counter electrode, and connecting to the thin film transistor through the connection electrode by a contact hole penetrating a part of the interlayer insulating film. A step of connecting the drain electrode and the display electrodes, and includes a said object is achieved.

A method of manufacturing a liquid crystal display device according to the present invention comprises a step of forming a gate electrode and a common wiring on a substrate, and a gate insulating layer formed on the substrate so as to cover the gate electrode and the common wiring. A step of forming a gate signal wiring, a source signal wiring and a connection electrode on the gate insulating layer, a step of forming a thin film transistor at the intersection of the gate signal wiring and the source signal wiring, A step of forming an interlayer insulating film on the gate insulating layer so as to cover the thin film transistor, the connection electrode, the source signal wiring, the gate signal wiring and the common wiring; and a liquid crystal driving display electrode on the interlayer insulating film. A step of forming
A step of connecting the drain electrode connected to the thin film transistor to the display electrode via the connection electrode through a contact hole penetrating a part of the interlayer insulating film; and facing the display electrode via a liquid crystal layer. And a step of forming a counter electrode, whereby the above object is achieved.

According to the present invention, with the above structure, the following actions can be obtained.

1. The display electrode 2 is formed so as to overlap with the adjacent source signal wiring 4 with the interlayer insulating film 9 interposed therebetween, thereby preventing the transmission light from being blocked by the wiring.

2. Since the lower-layer gate signal line 3, the source signal line 4, and the common line 25 are insulated from each other by the thick interlayer insulating film 9 having a small relative permittivity, generation of stray capacitance is suppressed.

3. By forming the display electrode 2 and the counter wiring 1 with the same material and using the same mask, the distance between the two electrodes is accurately formed.

4. By arranging the counter wiring 1 in a stripe shape on the counter substrate 27 side, generation of parasitic capacitance between the counter wiring 1 and peripheral wirings is prevented.

5. The counter wiring 1 is arranged in a stripe shape on the counter substrate 27 side, and in the longitudinal direction of the display electrode 2,
The longitudinal direction of the counter wiring 1 is made to have a constant angle, and the electric field strength generated between the display electrode 2 and the counter electrode 1 is varied depending on the position in one display region 2a.

6. By directly connecting the counter wiring 1 to the common wiring 25, the connection wiring 6 connected to the TFT is eliminated.

[7] By arranging the counter wiring 1 at an intermediate position between the two display electrodes 2 that sandwich the counter wiring 1, generation of parasitic capacitance between the counter wiring 1 and the display electrode 2 is prevented.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a plan view showing the configuration of one pixel portion of an active matrix substrate in a transmissive liquid crystal display device according to Embodiment 1 of the present invention. 2 and 3 are cross-sectional views taken along the lines BB 'and AA' shown in FIG. 1, respectively.

As shown in FIG. 1, the active matrix substrate 100 is provided with a plurality of display regions 2a sandwiched between the display electrodes 2 and the counter wiring 1 in a matrix. Further, a gate signal wiring 3 as a scanning wiring and a source signal wiring 4 as a signal wiring are provided so as to pass through the periphery of these display areas 2a and be orthogonal to each other.
Among these signal wirings, a part of the gate signal wiring 3 overlaps with a part of the counter wiring 1 described above. Further, a thin film transistor (hereinafter referred to as a TFT 22) that functions as a switching element is provided at the intersection of the gate signal wiring 3 and the source signal wiring 4, and the TFT 2
The second drain electrode 12 is finally connected to the display electrode 2 via the connection electrode 6a. The gate signal line 3 is connected to the gate electrode 5 of the TFT 22, and the TFT 22 is driven and controlled by the signal input to the gate electrode 5. The source signal wiring 4 is connected to the source electrode 11 of the TFT 22, so that a data signal is input to the source electrode 11 of the TFT 22. Where TFT
The drain electrode 12 of 22 is connected to the display electrode 2 by the contact hole 7 through the connection electrode 6a. Further, as shown in FIG. 3, the connection wiring 6a and the common wiring 25a
Each of them is sandwiched between the gate insulating films 15 as electrodes to form additional capacitance.

The configuration of the liquid crystal display device according to the first embodiment will be described in more detail below with reference to FIGS. 2 and 3.

First, in the TFT 22 of FIG. 2, the gate electrode 5 connected to the gate signal wiring 3 of FIG. 1 and the gate insulating film 15 covering the gate electrode 5 are provided on the lower transparent insulating substrate 20. Has been. The semiconductor layer 14 is formed on the gate insulating film so as to overlap the gate electrode 5,
The channel protection layer 13 is provided at the center of the semiconductor layer 14. Both ends of the channel protection layer 13 and the semiconductor layer 1
N which will be the source electrode 11 and the drain electrode 12 in a state of covering a part of 4 and being divided on the channel protection layer 13.
A + -a-Si layer is provided. The gate signal wiring 3 and the common wiring 25 may be made of a conductive material, and for example, ITO, Ti, Cr, Mo, Ta, Al and SnO ₂ , conductive resin, etc. are used. Further, not only a single-layer structure but also a multi-layer structure may be used.
a / Al, Ta / TaN, Ta ₂ O ₅ / Ta / Al, etc. are used. Note that the notation of Ta / Al is A
A film having a laminated structure in which Ta is formed on the film 1 is shown.

Next, the transparent conductive film 10a and the metal layer 8 are formed on the end portion of the source electrode 11 which is one of the n + -a-Si layers.
b is provided to form the source signal wiring 4 having a two-layer structure. In addition, the transparent conductive film 10a ′ and the metal layer 8 are formed on the end portion of the drain electrode 12 which is the other n + -a-Si layer.
b'is provided. The transparent conductive film 10a 'is extended to play a role of connecting the drain electrode 12 and the display electrode 2, and is integrated with the connection electrode 6 connected to one electrode 6a of the additional capacitor. In addition, TFT2
2, the gate signal wiring 3, the source signal wiring 4, and the connection electrode 6 are covered with an interlayer insulating film 9. Although the metal layer 8b 'and the drain electrode 12 are shown not to be in contact with each other in FIG. 2, there is no problem in characteristics even if they are in direct contact with each other. In addition, the metal films 8b and 8b '
And ITO, Ti, Cr, Mo, Ta, Al, SnO.
Other than ₂ , conductive resin, Ta / TaN, Ta / ITO, T
It may be formed in a laminated structure of a / TaN / ITO or the like.

As shown in FIG. 3, display electrodes 2 for forming pixels are provided on the interlayer insulating film 9 so as to face each other. The display electrode 2 is connected to the drain electrode 12 of the TFT 22 through the contact hole 7 penetrating the interlayer insulating film 9 through the transparent conductive film 10a ′ integrated with the connection electrode 6. Here, the display electrode 2 is
It is arranged in the peripheral portion of the display region 2a so as to overlap the source signal line 4 with the interlayer insulating film 9 interposed therebetween. The connection wiring 6 and the transparent conductive films 10a and 10a 'are
Made of O and SnO ₂ .

On the above-mentioned interlayer insulating film 9, the counter wiring 1 is formed in a stripe shape. The counter wiring 1 and the display electrode 2 are arranged so as to be parallel to each other in the longitudinal direction. The counter wiring 1 is arranged at a peripheral portion of the display area 2a and at a position where it does not overlap the adjacent source signal wiring 4. Further, the counter wiring 1 has a striped shape extending over a plurality of display regions 2a adjacent to each other in the longitudinal direction. The counter wiring 1 and the display electrode 2 are made in the same process, and these materials may be conductive materials, such as ITO, Ti, Cr, Mo, Ta,
A conductive resin other than Al and SnO ₂ may be used. Also, T
A laminated structure such as a / TaN may be used.

If the interlayer insulating film 9 is a colorless and transparent material having a sufficiently low relative dielectric constant and capable of forming a thick film,
Any insulating material may be used. Although the interlayer insulating film 9 is formed by using the photosensitive acrylic resin in the first embodiment, the photosensitive resin other than the acrylic resin may be used. Further, a thermosetting resin such as a polyimide resin or an epoxy resin may be used. However, it is preferable to use a photosensitive resin because the productivity is high, the acrylic resin is colorless and transparent, and the relative dielectric constant is low.

Next, the active matrix substrate of this embodiment as described above can be manufactured as follows.

First, on the lower transparent insulating substrate 20 such as a glass substrate, n + -a- which becomes the gate electrode 5, the gate insulating film 15, the semiconductor layer 14, the channel protective layer 13, the source electrode 11 and the drain electrode 12 is formed. The Si layer is sequentially formed. Here, the semiconductor material is not limited to a-Si (amorphous silicon), but may be p-Si (polysilicon) or microcrystalline silicon, or a conductive polymer material. The semiconductor layer 14 is formed of an intrinsic semiconductor layer, and the drain electrode and the source electrode are formed of an n + semiconductor layer. The channel protective film 13 and the gate insulating film 15, Chitsuka silicon (Si _x N _y), it is formed by the SiO ₂ and the insulating resin or the like.

The manufacturing process up to this point can be carried out in the same manner as the conventional active matrix substrate manufacturing method.

Next, the source signal wiring 4 and the connection electrode 6
Of the transparent conductive films 10a, 10a 'and the metal layer 8
b, 8b ', a film is sequentially formed by a sputtering method, and patterned into a predetermined shape.

Further, a photosensitive acrylic resin as the interlayer insulating film 9 is formed thereon by, for example, 5 μm by a spin coating method.
m.

Next, the resin is exposed in a desired pattern and developed with an alkaline solution. As a result, only the exposed portion is etched by the alkaline solution, and the contact hole 7 penetrating the interlayer insulating film 9 is formed.

After that, in order to form the display electrode 2 and the counter wiring 1 which form the display region 2a, a metal film is formed by a sputtering method and simultaneously patterned by etching. As a result, the display electrode 2 which is one of the electrodes forming the display region 2a is connected to the transparent conductive film 10a ′ connected to the drain electrode 12 of the TFT 22 through the contact hole 7 penetrating the interlayer insulating film 9. Will be. Further, the counter wiring 1 is patterned into a stripe shape. The display electrode 2 and the counter electrode 1 are formed by the same process and the same material. As described above, the material is a Ta metal film that is conductive and has no optical transparency.
It may be formed of a transparent conductive film such as i, Al, Cr, Mo, or a light-transmissive ITO film. Although the wet etching technique is used here as an example, a dry etching technique may be used.

Next, the unit pixel (display area 2
An alignment film 16 made of polyimide was formed on the surface of an active matrix substrate in which a) was arranged in a matrix, and the surface was rubbed. Similarly, a counter substrate 27 having a rubbing-treated alignment film 17 formed on the surface thereof
Then, a rod-shaped liquid crystal molecule 23 was filled with a liquid crystal composition between the active matrix substrates, and polarizing plates 18 and 19 were arranged on the outer surfaces of the two substrates. When there is no electric field (FIG. 1A), the liquid crystal molecules 23 have a slight angle with respect to the longitudinal direction of the stripe-shaped display electrode 2 and the counter wiring 1, that is, the long axis (optical axis) of the liquid crystal molecules and the electric field. The direction (perpendicular to the longitudinal direction of the display electrode 2 and the counter wiring 1) forms an angle of 45 ° or more and less than 90 °. The orientation of the liquid crystal molecules at the interface between the upper and lower substrates was parallel to each other. The dielectric anisotropy of the liquid crystal molecules is positive. When a voltage is applied to the gate electrode 5 of the TFT to turn on the TFT, the display electrode 2
When a voltage is applied to the display electrode 2 to induce an electric field E between the opposing wirings, the liquid crystal molecules turn in the electric field direction as shown in FIG. 1B. The polarization transmission axes of the two polarizing plates 18 and 19 arranged on the surfaces of the upper and lower substrates are set at a predetermined angle (for example,
It is possible to change the light transmittance by applying an electric field by arranging the polarization transmission axes in crossed Nicols in which their polarization transmission axes are orthogonal to each other. As described above, in the display system of the present invention, it is possible to perform display with contrast even without the transparent electrode which is conventionally required for the counter substrate 27. For this reason, all of 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 on a counter substrate, 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 0. The viewing angle direction in which the phase difference is 0 is only in the front direction, that is, in the direction perpendicular to the substrate interface, and a slight tilt causes a birefringence phase difference. Cause inversion. 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, the change in brightness when the viewing angle direction is changed is small, and the viewing angle characteristics are significantly improved.

In the active matrix substrate thus obtained, the interlayer insulating film 9 is formed between the gate signal wiring 3, the source signal wiring 4 and the TFT 22, the liquid crystal display electrode 2 and the counter wiring 1. Therefore, the display electrode 2 and the counter wiring 1 can be formed so as to overlap the wirings 3 and 4 and the TFT 22, and the surface can be flattened.

For example, as shown in FIG. 2, the display electrode 2 is superimposed on the source bus line connected to the TFT for supplying the data signal via the interlayer insulating film 9, while the counter wiring 1 is formed.
Are arranged such that they form a pair across the display area 2a and do not overlap with the adjacent source signal wiring 4,
It is possible to expand the transmission area of the backlight light.

Therefore, when a transmissive liquid crystal display device is constructed in which liquid crystal is interposed between the active matrix substrate and the counter substrate, the aperture ratio can be improved and the electric field caused by the wirings 3 and 4 can be improved. Can be shielded by the display electrode 2 forming the display region 2a and the counter wiring 2 to prevent liquid crystal misalignment, and each wiring 3,
4 and the TFT 22 can prevent the liquid crystal alignment defect due to the step.

The acrylic resin forming the interlayer insulating film 9 has a relative permittivity of 1.5 to 3.5, which is lower than that of the inorganic film (relative permittivity of silicon nitride 8), and the spin coating method is used. Since the thickness can be easily made as thick as 1.0 to 10.0 μm, the capacitance between the gate signal wiring 3 and the display electrode 2 can be reduced. This makes it possible to reduce the sagging and distortion of the signal waveform. Similarly,
It is possible to reduce the capacitance between each of the wirings 3 and 4, the display electrode 2, and the counter wiring 1, thereby reducing the sagging and distortion of the signal waveform. Therefore, each wiring 3,
It is possible to further improve the effect of crosstalk or the like on the display caused by the capacitance component between the display element 4, the display electrode 2, and the counter wiring 1, and it is possible to obtain a good and bright display.
In addition, since the tapered shape of the contact hole 7 can be improved by performing patterning by exposure and alkali development, a good connection between the display electrode 2 and the transparent conductive film 10a ′ forming the connection electrode 6 can be achieved. You will be able to get it. Moreover, the patterning does not require a photoresist process, which is advantageous from the viewpoint of improving productivity. Here, the acrylic resin used as the interlayer insulating film 9 is colored before coating, but can be made more transparent by subjecting it to an entire surface exposure process after patterning. It should be noted that such a transparent treatment of the resin is not limited to an optical treatment, and can be a chemical treatment. In addition, acrylic resin is a preferable material from the viewpoint of high transparency.

(Embodiment 2) When the counter electrode 1 and the display electrode 2 were formed on the interlayer insulating film 9, it was considered difficult to obtain good display characteristics due to an increase in stray capacitance. However, as described above, the interlayer insulating film 9 used in the liquid crystal display device of the present invention has a feature that the dielectric constant is extremely low and the layer thickness can be increased. The stray capacitance can be made extremely small even if the configuration in which it is arranged so as to overlap the source signal line 4 via the film 9 is adopted. Therefore, the aperture ratio and the contrast of the liquid crystal display device can be improved by the effect brought about by superposing the counter electrode 1 and the source signal wiring 4 on the interlayer insulating film 9. With the same effect, the display electrode 2
Even when the gate electrodes are arranged so as to overlap with the gate signal line 3 via the interlayer insulating film 9, the generation of stray capacitance can be suppressed to the minimum, and thus the aperture ratio and the contrast can be improved. To

In the horizontal electric field mode, and since the film is flattened by the interlayer insulating film and the reverse tilt does not occur, the liquid crystal display device according to the present invention basically does not need a black mask. However, as in the first and second embodiments, the counter wiring 1 is formed in the display area 2a.
When the distance between the display electrode 2 and the display electrode 2 is different,
There is a concern that a problem of orientation failure may occur due to a change in response speed due to a difference in distance between the two. Therefore, a black mask may be provided between the counter wiring 1 and the display electrode 2 which are close to each other and in which an alignment defect may occur.

(Third Embodiment) FIG. 4 is a plan view showing a liquid crystal display device according to a third embodiment of the present invention. 5 and 6 are cross-sectional views taken along the lines BB 'and AA' shown in FIG. 3, respectively. In this Embodiment 3, Embodiments 1 and 2
2 is that the position of the counter wiring 1 is arranged substantially in the center of the display area 2a and that the counter wiring 1 is arranged on the counter substrate side.

That is, as can be seen from FIGS. 4 to 6, the liquid crystal driving display electrode 2 is provided on the active matrix substrate, and this point has the same configuration as in the first and second embodiments. On the other hand, on the counter substrate side, the counter wiring 1 is arranged in a stripe shape at the center of the display area 2a, and this point is a characteristic of this embodiment.

A method of manufacturing a liquid crystal display device according to the third embodiment will be described.
This will be described with reference to FIGS.

Each manufacturing process up to the formation of the interlayer insulating film 9 is
Since the process is the same as that of the first embodiment, the subsequent manufacturing process will be described. An alignment film 16 made of polyimide is formed on the surface of an active matrix substrate 28 in which unit pixels (display area 2a) are arranged in a matrix.
The surface was rubbed.

Next, a conductive film is formed on the counter substrate 27 by a vapor deposition method, and a photolithography process and an etching process are performed.
The stripe-shaped opposing wiring 1 was formed. Here, Ta is used as the material of the conductive film, but Ti, Al, Cr,
ITO or the like may be used. Subsequently, an alignment film 17 made of polyimide was formed on the surface of the counter substrate 27, and the surface was rubbed.

Counter substrate 27 formed as described above
Then, a rod-shaped liquid crystal molecule 23 was filled with a liquid crystal composition between the active matrix substrates. Further, polarizing plates 18 and 19 are arranged on the surfaces of the active matrix substrate 28 and the counter substrate 27 opposite to the alignment films. When there is no electric field, the liquid crystal molecules 23 form a slight angle with respect to the longitudinal direction of the stripe-shaped display electrode 2 and the counter wiring 1, that is, the major axis (optical axis) of the liquid crystal molecule and the direction of the electric field (display electrode 2 and counter wiring). (1 is perpendicular to the longitudinal direction) and has an angle of 45 ° or more and less than 90 °. The alignment of the liquid crystal molecules at the interface with the upper and lower substrates was made parallel to each other. The dielectric anisotropy of the liquid crystal molecules is positive. Here, when a voltage is applied to the gate electrode 5 of the TFT to turn on the TFT, a voltage is applied to the display electrode 2, and when an electric field E is induced between the display electrode 2 and the counter wiring 1, liquid crystal molecules are generated in the electric field direction. Change direction (Fig. 4 (a)). Further, in FIG. 5 and FIG. 6, since the thickness direction is enlarged and shown, the electric field direction E seems to be inclined, but in the actual liquid crystal display device, the width of the display region 2a ′ is 40 μm. Since the thickness of the liquid crystal layer is about 6 μm, which is smaller than that of ˜80 μm by almost one digit, the electric field component in the thickness direction of the liquid crystal layer is extremely small, and it can be considered that the electric field direction is substantially parallel to the substrate surface. In the above configuration, by arranging the polarization transmission axes of the two polarizing plates 18 and 19 arranged on the surfaces of the upper and lower substrates at a predetermined angle (for example, crossed Nicols where the polarization transmission axes of the two are orthogonal to each other), the It is possible to change the transmittance of.

As described above, by arranging the counter wiring 1 substantially at the center of the counter substrate 27, the stray capacitance can be further reduced as compared with the first and second embodiments. Therefore, the sag and distortion of the signal waveform due to the stray capacitance can be improved more effectively. Further, it is possible to prevent the generation of off current due to the parasitic capacitance. Further, in the case of the configuration in which the distance between the counter wiring 1 and the display electrode 2 is different in the display area 2a as in the first and second embodiments, it is based on the change in response speed due to the difference in distance between the two. Although there is a concern that a problem of poor orientation may occur, such a problem does not occur in the present embodiment, and it is not necessary to provide the black mask mentioned in the first and second embodiments.

(Fourth Embodiment) FIG. 7 is a plan view showing a liquid crystal display device according to a fourth embodiment of the present invention. 8 and 9 are cross-sectional views taken along the lines BB 'and AA' shown in FIG. 7, respectively. The fourth embodiment differs from the third embodiment in that the counter wiring 1 in the longitudinal direction is arranged at a certain angle with respect to the longitudinal direction of the display electrode.

That is, as can be seen from FIGS. 7A and 7B, in the structure in which the counter wiring 1 is arranged on the counter substrate 27 side, the longitudinal direction of the counter wiring 1 is set with respect to the longitudinal direction of the display electrode 2. The counter wiring 1 is arranged so as to be formed in a direction having a certain angle, preferably in a direction along a diagonal line of the quadrilateral display area 2a formed by the source signal wiring 4 and the gate signal wiring 3. There is.

Assuming that the display area 2a is a set of a plurality of microscopic areas, the above-mentioned structure is adopted, so that the display area 2a shown in FIGS.
As shown in the cross-sectional view of FIG. 5, the electric field strength between the display electrode 2 and the counter wiring 1 changes depending on the position of the minute area in the display area 2a. Therefore, the rotation angle of the liquid crystal molecules changes in the minute regions at different positions,
This also affects the value of the birefringence phase difference, and the inclination of the polarization plane of circularly polarized light propagating through the liquid crystal layer is different. Therefore, in the liquid crystal layer of the display area 2a, light having different phase differences or polarization planes depending on the position propagates, and this significantly improves the viewing angle characteristics.

(Fifth Embodiment) FIG. 10A is a plan view showing a liquid crystal display device according to a fifth embodiment of the present invention.

In FIG. 10A, the common wiring 25 is
It is different from the other embodiments in that it is arranged in the vicinity of the gate signal wiring 3 connected to the TFT 22.

By adopting such a configuration, it is possible to suppress the occurrence of alignment disorder of the liquid crystal molecules in the central portion of the display area 2a. That is, since the alignment disorder area is limited to the peripheral portion of the display area 2a, the display quality is significantly improved in the entire display area. Further, it is possible to obtain a higher quality display by covering only the peripherally disturbed portion with a black mask.

(Sixth Embodiment) FIG. 10B is a plan view showing a liquid crystal display device according to a sixth embodiment of the present invention.

According to FIG. 10B, the counter wiring 1 is directly connected to the common wiring 25 through the contact hole 7 provided in the interlayer insulating film 9, and the display electrode 2 is also similarly interlayer-insulated. It is directly connected to the TFT 22 through the contact hole 7 provided in the film 9.

By adopting such a structure, as compared with the case where the storage capacitor is formed on the drain electrode side via the interlayer insulating film 9, the connection electrode 6 formed of the transparent conductive film in the display region 2a. It becomes unnecessary to dispose, and the transmittance of transmitted light is significantly improved, and the contrast and the brightness can be improved. Further, with such a configuration, it is possible to solve the problem of delay of the data signal due to the wiring resistance of the connection wiring 6.

(Embodiment 7) FIG. 10C is a plan view showing a liquid crystal display device of Embodiment 7 of the present invention.

According to FIG. 10C, the counter wiring 1 is directly connected to the common wiring 25 as in the case of the seventh embodiment, and the counter wiring 1 drives between the display electrodes 2 for driving the liquid crystal for driving the display area 2a. It is arranged so as to come to an intermediate position.

By adopting such a configuration, it is possible to prevent the generation of parasitic capacitance between the display electrode 2 and the counter wiring 1, so that it is possible to suppress the signal waveform from sagging or distortion. Further, FIG. 10D has a configuration in which the features of the seventh embodiment and the features of the fifth embodiment are combined.

In the present embodiment, the counter electrode 1 is illustrated as a strip electrode, but the counter electrode 1 and the display electrode 2 may have a comb tooth shape. That is, the inter-electrode distance between the counter electrode 1 and the display electrode 2 may be fixed and the shapes may be intermeshed with each other.

The drive signal of the liquid crystal display device of the present invention may be the same drive signal as that of the TN mode liquid crystal display device, and the applied voltage is applied to the liquid crystal material and the cell structure (for example, between the display electrode 1 and the counter electrode 2). It is properly selected according to the distance. Further, the common wiring may have a constant potential. Further, in the liquid crystal display device of the present invention, the additional capacitance is formed between the connection electrode 6a and the common wiring 25a, but if the voltage can be held by the liquid crystal material, the common wiring 25a may be omitted. Further, the additional capacitance may be provided by forming an insulating film on the gate signal wiring 3.

[0074]

According to the above embodiment, the following actions and effects can be obtained.

1. Since the display electrode 2 is formed so as to overlap with the adjacent source signal wiring 4 with the interlayer insulating film 9 interposed therebetween, it is possible to prevent the transmission light from being blocked by the wiring, thereby improving the aperture ratio. It achieves high contrast and high brightness.

2. Since the lower-layer gate signal line 3, the source signal line 4, and the common line 25 are insulated from each other by the thick interlayer insulating film 9 having a small relative permittivity, generation of stray capacitance is suppressed. As a result, it is possible to prevent fluctuations in the drive capacitance of the liquid crystal, and it is possible to accurately transmit a data signal with little sagging or distortion to the liquid crystal layer, which enables high contrast display.

3. By forming the display electrode 2 and the counter wiring 1 using the same material and using the same mask, the distance between the two electrodes can be accurately formed, and the manufacturing cost and the yield are improved.

4. By arranging the counter wiring 1 in the form of stripes on the counter substrate 27 side, the generation of parasitic capacitance between the counter wiring 1 and the peripheral wiring is prevented, so that the deterioration of the display quality due to the delay of the counter signal is prevented. .

5. The counter wiring 1 is arranged in a stripe shape on the counter substrate 27 side, and in the longitudinal direction of the display electrode 2,
By making the longitudinal direction of the counter wiring 1 have a constant angle, the electric field strength generated between the display electrode 2 and the counter electrode 1 is made different depending on the position in one display region 2a, thereby displaying a wide viewing angle. To enable.

6. By directly connecting the counter wiring 1 to the common wiring 25 and eliminating the connection wiring 6 connected to the TFT, it is possible to prevent the delay of the data signal due to the influence of the wiring resistance and improve the transmittance of the transmitted light. .

7. By arranging the counter wiring 1 at an intermediate position between the two display electrodes 2 sandwiching the counter wiring 1, the generation of the parasitic capacitance between the counter wiring 1 and the display electrode 2 is prevented. It is possible to suppress and prevent the generation of off-current.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a liquid crystal display device according to a first embodiment of the present invention.

2 is a cross-sectional view taken along the line B-B 'of the liquid crystal display device of FIG.

FIG. 3 is a cross-sectional view taken along the line A-A ′ of the liquid crystal display device of FIG.

FIG. 4 is a plan view showing a liquid crystal display device according to a second embodiment of the present invention.

5 is a cross-sectional view taken along the line B-B ′ of the liquid crystal display device of FIG.

6 is a cross-sectional view taken along the line A-A ′ of the liquid crystal display device of FIG.

FIG. 7 is a plan view showing a configuration of a liquid crystal display device according to a fifth embodiment of the present invention.

8 is a cross-sectional view taken along the line B-B ′ of the liquid crystal display device of FIG.

9 is a cross-sectional view taken along the line A-A ′ of the liquid crystal display device of FIG.

FIG. 10A is a plan view showing a configuration of a liquid crystal display device according to a fifth embodiment of the present invention. FIG. 6B is a plan view showing the configuration of the liquid crystal display device of Embodiment 6 of the present invention.
FIG. 13C is a plan view showing the configuration of the liquid crystal display device of Embodiment 7 of the present invention. FIG. 7D is a plan view showing another configuration of the liquid crystal display device of Embodiment 7 of the present invention.

11A and 11B are plan views showing a configuration of a conventional liquid crystal display device.

FIG. 12 is a cross-sectional view showing a configuration of a conventional liquid crystal display device.

[Explanation of symbols]

 1 counter wiring 2 display electrode 2a display area 2b display electrode lead-out portion 3 gate signal wiring 4 source signal wiring 5 gate electrode 6 connection electrode 7 contact hole 8b ', 8b metal layer 9 interlayer insulating film 10a, 10a' transparent conductive film 11 source Electrode 12 Drain electrode 13 Channel protection layer 14 Semiconductor layer 15 Gate insulating film 16 Lower alignment film 17 Upper alignment film 18, 19 Polarizing plate 20 Lower transparent insulating substrate 21 Upper transparent insulating substrate 22 TFT 23 Liquid crystal molecule 24 Liquid crystal layer 25 common wiring 27 counter substrate 28 active matrix substrate

Claims (13)

[Claims] 1. A substrate, a gate signal wiring and a gate insulating film provided on the substrate, a source signal wiring provided on the gate insulating film, and a gate signal provided on the gate insulating film. A thin film transistor formed at each intersection of a wiring and the source signal wiring, a drain electrode connected to the thin film transistor, a connection electrode connected to the drain electrode, a part of the connection electrode, and the gate insulating film. An active line having a common wire for forming a storage capacitor via the interlayer insulating film formed on the gate insulating film, and a liquid crystal driving display electrode and a counter electrode provided on the interlayer insulating film. A liquid crystal display device comprising: a matrix substrate; a counter substrate facing the active matrix substrate; and a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, A liquid crystal in which the display electrode extends in a first direction within the display region, and the counter electrode and the source signal line extend in the first direction within the display region and across a plurality of the display regions. Display device. 2. The liquid crystal display device according to claim 1, wherein at least one of the display electrode and the counter electrode is formed so as to overlap with the source signal line. 3. The liquid crystal display device according to claim 1, wherein at least one of the display electrode and the counter electrode is formed so as to overlap with the gate signal line. 4. A substrate, a gate signal wiring and a gate insulating film provided on the substrate, a source signal wiring provided on the gate insulating film, and a gate signal provided on the gate insulating film. A thin film transistor formed at each intersection of a wiring and the source signal wiring, a drain electrode connected to the thin film transistor, a connection electrode connected to the drain electrode, a part of the connection electrode, and the gate insulating film. An active line having a common wire for forming a storage capacitor via the interlayer insulating film formed on the gate insulating film, and a liquid crystal driving display electrode and a counter electrode provided on the interlayer insulating film. A liquid crystal display device comprising: a matrix substrate; a counter substrate facing the active matrix substrate; and a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, A liquid crystal display device in which the counter electrode is directly connected to the common wiring through a contact hole provided in the interlayer insulating layer. 5. A substrate, a gate signal wiring and a gate insulating film provided on the substrate, a source signal wiring provided on the gate insulating film, and a gate signal provided on the gate insulating film. A thin film transistor formed at each intersection of a wiring and the source signal wiring, a drain electrode connected to the thin film transistor, a connection electrode connected to the drain electrode, a part of the connection electrode, and the gate insulating film. An active line having a common wire for forming a storage capacitor via the interlayer insulating film formed on the gate insulating film, and a liquid crystal driving display electrode and a counter electrode provided on the interlayer insulating film. A liquid crystal display device comprising: a matrix substrate; a counter substrate facing the active matrix substrate; and a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, Furthermore, a counter substrate facing the active matrix substrate and having a liquid crystal driving counter electrode,
A liquid crystal display device comprising the active matrix substrate and a liquid crystal layer sandwiched between the counter substrates. 6. The liquid crystal display device according to claim 5, wherein the display electrode is formed so as to overlap with the source signal line or the gate signal line. 7. The longitudinal direction of the counter electrode has a constant angle with respect to the longitudinal direction of the display electrode.
Alternatively, the liquid crystal display device according to claim 6. 8. The thickness of the interlayer insulating layer is 1.0 to 10.
The liquid crystal display device according to claim 1, wherein the liquid crystal display device has a thickness of 0 μm. 9. The dielectric constant value of the interlayer insulating layer is 1.5 to
The liquid crystal display device according to claim 1, which is 3.5. 10. The liquid crystal display device according to claim 1, wherein the material of the interlayer insulating film is an organic resin. 11. The liquid crystal display device according to claim 1, wherein an image is displayed by rotationally driving liquid crystal layer molecules in the display region in a direction substantially horizontal to the substrate surface. 12. A method of manufacturing a liquid crystal display device, comprising: forming a gate electrode and a common wiring on a substrate; and forming a gate insulating layer on the substrate so as to cover the gate electrode and the common wiring. A step of forming, a step of patterning a gate signal wiring, a source signal wiring and a connection electrode on the gate insulating layer, a step of forming a thin film transistor at an intersection of the gate signal wiring and the source signal wiring, A step of forming an interlayer insulating film on the gate insulating layer so as to cover the thin film transistor, the connection electrode, the source signal wiring, the gate signal wiring and the common wiring; and a liquid crystal driving display on the interlayer insulating film. The step of forming an electrode and a counter electrode, and the step of connecting to the thin film transistor through the connection electrode by a contact hole penetrating a part of the interlayer insulating film. The method comprises the steps of connecting the drain electrode and the display electrode. 13. A method of manufacturing a liquid crystal display device, comprising: forming a gate electrode and a common wiring on a substrate; and forming a gate insulating layer on the substrate so as to cover the gate electrode and the common wiring. A step of forming, a step of patterning a gate signal wiring, a source signal wiring and a connection electrode on the gate insulating layer, a step of forming a thin film transistor at an intersection of the gate signal wiring and the source signal wiring, A step of forming an interlayer insulating film on the gate insulating layer so as to cover the thin film transistor, the connection electrode, the source signal wiring, the gate signal wiring, and the common wiring; and a liquid crystal driving display on the interlayer insulating film. A step of forming an electrode, and a drain electrode connected to the thin film transistor via the connection electrode by a contact hole penetrating a part of the interlayer insulating film The method comprises the steps of connecting the said display electrodes, and forming a counter electrode opposed to the display electrodes through the liquid crystal layer.