JPH0943638A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal element which is hardly affected by the parasitic capacitance of a TFT and has a wide angle of visibility. SOLUTION: A pixel electrode 22 is formed on a TFT substrate 11, a lower layer electrode 31 and an additional capacitance electrode 38 are formed on a counter substrate 12, a color filter 33, etc., are formed thereon and upper layer electrodes 35a, 35b are formed on a color filter 33, etc. The upper electrode 35a is connected to the lower electrode 31. Liquid crystal 13 is enclosed between the TUFT substrate 11 and the counter substrate 12 to constitute the liquid crystal display element. The driving voltage applied between the lower layer electrode 31 and the pixel electrode 22 is applied to the liquid crystal 13 as it is in a region where the upper layer electrode 35a is arranged, and is lowered by a color filter 33 and applied to the liquid crystal 13 in a region where the upper layer 35b is arranged. Further, the additional capacitance is individually connected to the liquid crystal capacitance in both regions. Consequently, the lowering of voltage of the pixel electrode 22 due to the parasitic capacitance of the TFT 21 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a wide viewing angle.

[0002]

2. Description of the Related Art Liquid crystal display devices can be made thin and lightweight and are used as display devices for various electronic devices.
However, the liquid crystal display element has a drawback that the viewing angle is narrower than that of a CRT or the like, and that the viewing angle dependency during halftone display is remarkable. For example, in a TN liquid crystal display device configured by sandwiching a TN (twisted nematic) liquid crystal cell between a pair of polarizing plates, the viewing angle is practically sufficient in binary display, but the viewing angle is narrow in multi-gradation display. Has the drawback.

As a method of widening the viewing angle, each pixel electrode is divided into a plurality of partial pixel electrodes, and a control electrode facing the partial pixel electrode is arranged, whereby a control capacitor for voltage drop is connected in series with the liquid crystal capacitor. A method of connecting to is proposed. In this method, since the voltages applied to the liquid crystal by the partial pixel electrodes are different from each other, regions having different alignment states are formed in each pixel, and the viewing angle is widened.

However, this method has a drawback that a control electrode must be formed in the process of forming a TFT, which easily causes a defect of the TFT and reduces the yield of the TFT substrate.

In order to improve these drawbacks, an insulating film (color filter, overcoat layer, etc.) formed on the counter electrode is divided into a plurality of counter electrodes on the side of the substrate facing the substrate on which the TFT is formed. ) Has been proposed to lower the voltage. Even in this method, since the voltages applied to the liquid crystal of each divided pixel are different from each other,
Regions having different alignment states are formed in each pixel, and the viewing angle is widened.

Further, in such a liquid crystal display element, the control capacitor and the liquid crystal capacitor are respectively connected to the source electrode of the TFT as an active element. Therefore, the voltage applied to the liquid crystal capacitance is T when the gate pulse is turned off.
The voltage of the pixel electrode also drops due to the parasitic capacitance existing between the gate and source of the FT. Therefore, the voltage applied to the liquid crystal also drops. As a method of reducing this voltage drop, there is known a method of connecting an additional capacitance (compensation capacitance) in parallel with a liquid crystal capacitance by forming an additional electrode facing the pixel electrode via an insulating film. One additional capacitor is formed for each pixel and is commonly connected to the divided pixels.

[0007]

However, the method of forming the additional electrode on the TFT substrate, like the case of forming the control electrode on the TFT substrate, is apt to cause defects of the TFT and lowers the yield of the TFT substrate. There is. Further, the method of commonly connecting one additional capacitance to the divided pixels cannot sufficiently reduce the voltage drop of the pixel electrode due to the influence of the parasitic capacitance of the TFT.

The present invention has been made in view of the above circumstances, and provides a liquid crystal display element having a high yield rate, a small voltage drop of a pixel electrode due to the influence of a parasitic capacitance of a TFT, and a wide viewing angle. With the goal.

[0009]

In order to achieve the above object, a liquid crystal display element according to a first aspect of the present invention has a first electrode formed in each pixel region and a corresponding first electrode.
A first substrate on which an active element connected to the electrodes of the second substrate is formed, a second substrate arranged to face the first substrate, and a second substrate facing the first substrate of the second substrate. A second electrode formed on a part of each pixel region of the surface;
An insulating film formed on the electrode of the third electrode, and a third electrode formed on a part of each pixel region on the insulating film so as to be connected to the second electrode and to face the electrode of the first electrode. An electrode; a fourth electrode formed on a part of each pixel region on the insulating film so as to partly face the second electrode and to face the first electrode; A fifth electrode, which is connected to the opposing first electrode and is opposed to the fourth electrode, is formed in a part of each pixel region on the substrate, and between the first and second substrates. And a sealed liquid crystal.

In order to achieve the above object, the second aspect of the present invention
According to another aspect of the liquid crystal display element, a first substrate on which a first electrode is formed in each pixel region, and an active element connected to the corresponding first electrode is formed, and the first substrate. And a second substrate formed so as to face the first electrode in a part of each pixel region of a surface of the second substrate facing the first substrate. A second electrode, a first insulating film formed on the second electrode,
On a part of each pixel region on the first insulating film, a third electrode connected to the second electrode and formed opposite to the first electrode, and on the first insulating film. A fourth electrode formed in a part of each pixel region of the second electrode and a part of the second electrode and the first electrode, and on the third and fourth electrodes. The formed second insulating film and the first insulating film formed in a part of each pixel region on the second insulating film so as to oppose the fourth electrode and connected to the opposing first electrode. 5 electrode, and a liquid crystal sealed between the first and second substrates.

In order to achieve the above object, the third aspect of the present invention
According to another aspect of the liquid crystal display element, a first substrate on which a first electrode is formed in each pixel region, and an active element connected to the corresponding first electrode is formed, and the first substrate. A second substrate disposed to face each other, a second electrode formed in a part of each pixel region on a surface of the second substrate facing the first substrate, and the second electrode An insulating film formed on the insulating film, a third electrode formed on a part of each pixel region on the insulating film so as to face the first electrode, and a second electrode formed on the insulating film. A part of each pixel region on the second substrate, and a fourth electrode formed to partly face each other and to face the first electrode, and connected to the first electrode facing each other. A fifth electrode formed to face the fourth electrode; a liquid crystal sealed between the first and second substrates;
It is characterized by having.

In order to achieve the above object, the fourth aspect of the present invention
According to another aspect of the liquid crystal display element, a first substrate on which a first electrode is formed in each pixel region, and an active element connected to the corresponding first electrode is formed, and the first substrate. And a second substrate that is formed in each pixel region on a surface of the second substrate that faces the first substrate and that is connected to the first electrode that faces the second substrate. An electrode, a first insulating film formed on the second electrode,
A third electrode formed on a part of each pixel region on the first insulating film and formed to face the first and second electrodes, and formed on the third electrode. A second insulating film,
A fourth electrode formed on a part of each pixel region on the second insulating film and facing the first to third electrodes, and a liquid crystal sealed between the first and second substrates. And are provided.

According to the liquid crystal display device of the first to fourth aspects of the present invention, a region where the drive voltage is applied almost as it is and a region where the drive voltage is stepped down and applied by the insulating film are formed in each pixel. It Therefore, the viewing angle becomes wide. Also,
Since the additional capacitance is formed independently in each of the region where the drive voltage is applied almost as it is and the region where the drive voltage is stepped down by the insulating film, the influence of the parasitic capacitance of the active element can be reduced. Further, since the structure on the side of the first substrate on which the active element is formed is simple, the liquid crystal display element can be manufactured relatively easily with high yield.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
An FT liquid crystal display device will be described as an example with reference to the drawings. (First Embodiment) FIG. 1 shows a sectional structure of a TN liquid crystal display element according to the first embodiment, FIG. 2 shows a planar structure of a TFT substrate, and FIG. 3 shows a planar structure of an opposite substrate.

As shown in FIG. 1, this liquid crystal display device is
A pair of transparent substrates 11 and 1 joined by a sealing material SC
2 and a TN sealed between the pair of transparent substrates 11 and 12
A liquid crystal cell 16 including a (twisted nematic) liquid crystal 13 and polarizing plates 14 and 15 arranged with the liquid crystal cell 16 interposed therebetween.

The transparent substrates 11 and 12 are made of glass or the like. On the lower transparent substrate (hereinafter, TFT substrate) 11,
As shown in FIGS. 1 and 2, T as an active element
FTs (thin film transistors) 21 and pixel electrodes 22 are arranged in a matrix, and an alignment film 23 is arranged thereon.

The source electrode of each TFT 21 is connected to the corresponding pixel electrode 22, the gate electrode of each row TFT 21 is connected to the corresponding gate line GL, and each row TFT 2 is connected.
The drain electrode of No. 1 is connected to the corresponding data line DL. The pixel electrode 22 is formed of a transparent conductive film made of ITO (oxide of indium and tin) or the like, and
A signal voltage (writing voltage) is applied via 21.

As shown in FIG. 3A, on the other transparent substrate (hereinafter referred to as a counter substrate) 12, stripe-shaped lower layer electrodes (counter electrodes) 31 facing a plurality of pixel electrodes 22 and pixels in each pixel region are formed. An additional capacitance electrode 38 facing the electrode 22 is formed. The lower electrode 31 and the additional capacitance electrode 38 are formed of ITO having a thickness of about 0.08 ± 0.02 μm. The lower layer electrodes 31 are connected to each other and to an electrode terminal 37 to which a common voltage (common voltage) Vcom is supplied. The additional capacitance electrode 38 is connected to each pixel electrode 22 formed on the TFT substrate 11. Also,
A black mask 32 having a light-shielding property is arranged in a portion facing the TFT 21 on the counter substrate 12 and a portion facing the portion between the pixel electrodes 22.

In each pixel area on the lower layer electrode 31 and the additional capacitance electrode 38, color filters 33 (33) of RGB colors are provided.
R, 33G, 33B) are arranged. The color filter 33 is made of an acrylic resin or the like having a thickness of about 1 μm, and is colored R, G, or B with a pigment. The color filter 33 may be arranged by any method such as stripe, diagonal mosaic, or triangular mosaic.
An overcoat layer (protective layer) 34 is disposed on the entire surface of the substrate on the color filters 33 (33R, 33G, 33B). The overcoat layer 34 is made of acrylic resin, SiO2 or the like having a thickness of about 1 μm.

Above the overcoat layer 34, FIG.
As shown in (B), stripe-shaped upper layer electrodes 35a and 35b facing the plurality of pixel electrodes 22 are formed, respectively. The upper layer electrodes 35a and 35b have a thickness of 0.08 ±
It is composed of ITO having a thickness of about 0.02 μm, and they are connected to each other at the ends of the electrodes. The upper layer electrode 35a is connected to the lower layer electrode 31, and the common voltage Vcom is applied. The upper layer electrode 35b is arranged so that a part thereof faces the lower layer electrode 31.

An alignment film 36 made of polyimide or the like is formed on the upper layer electrodes 35a and 35b and the overcoat layer 34. The lower alignment film 23 in FIG. 1 is subjected to alignment treatment such as rubbing in the direction indicated by the broken line in FIG. 4 (direction of 0 °), and the upper alignment film 36 is subjected to the direction indicated by the solid line in FIG. The orientation treatment is applied to the (90 ° direction).

The liquid crystal 13 is composed of a nematic liquid crystal to which a chiral agent is added, and is 90 ° clockwise from the TFT substrate 11 toward the counter substrate 12 according to the alignment treatment.
(0 ° to −90 °) Twisted and oriented.

The lower (light incident side) polarizing plate 14 is set so that its transmission axis is perpendicular (90 °) to the direction of the alignment treatment applied to the lower alignment film 23, and the upper (light incident side) polarizing plate 14 is set. Output side)
The polarizing plate 15 is set so that its transmission axis is perpendicular to the transmission axis of the lower polarizing plate 14.

Next, the operation of the liquid crystal display device having the above structure will be described with reference to FIGS. FIG. 5 shows an enlarged cross section of one pixel. As shown, each pixel has an upper electrode 35.
It is divided into a region (hereinafter referred to as a normal pixel) A1 in which a is formed and a region (hereinafter referred to as a voltage drop pixel) A2 in which the upper layer electrode 35b is formed. The area ratio of the upper layer electrodes 35a and 35b, that is, the area ratio of the normal pixel A1 and the voltage drop pixel A2 is in the range of 7: 3 to 5: 5.

In such a structure, as shown in FIG. 5, the capacitance between the pixel electrode 22 and the upper layer electrode 35a is set to the first value.
The liquid crystal capacitance CLC1, the capacitance between the pixel electrode 22 and the upper layer electrode 35b is the second liquid crystal capacitance CLC2, the capacitance between the upper layer electrode 35a and the additional capacitance electrode 38 is the first additional capacitance CS1, the upper layer electrode 35b and the lower layer electrode 31. When the capacitance between and is the control capacitance CCF, and the capacitance between the upper layer electrode 35b and the additional capacitance electrode 38 is the second additional capacitance CS2, the equivalent circuit of each pixel is as shown in FIG.

When the drive voltage applied between the electrode terminal 37 and the pixel electrode 22 is V0, the voltage VLC1 applied to the first liquid crystal capacitor CLC1 and the voltage VLC2 applied to the second liquid crystal capacitor CLC2 are given by And expressed by the equation 2.

[0027]

[Equation 1] VLC1 = V0

[Formula 2] VLC2 = V0 × CCF / (CCF + CLC2 + CS2)

As shown in the equations 1 and 2, the normal pixel A1
The drive voltage V0 is applied to the liquid crystal 13 of FIG. 3 as it is, and the drive voltage V0 is divided and applied to the liquid crystal 13 of the voltage drop pixel A2. Therefore, regions with different applied voltages, that is, regions with different alignment states are formed in each pixel,
Since these optical characteristics are averaged, the viewing angle becomes wide.

The voltage VLC2 applied to the liquid crystal 13 of the voltage drop pixel A2 is the area of the facing portion of the upper layer electrode 35b and the lower layer electrode 31, the color filter 33 and the overcoat layer 3.
4 can be changed and adjusted arbitrarily by changing the thickness of No. 4, the area of the additional capacitance electrode 38, and the like. Therefore, the conditions for obtaining the optimum voltage VLC2 are obtained in advance by experiments or the like, and each is arranged or formed according to the conditions.

The first additional capacitance CS1 is connected in parallel to the first liquid crystal capacitance CLC1, and the second additional capacitance CS2 is connected in parallel to the second liquid crystal capacitance CLC2. Therefore,
The voltage drop of the pixel electrode 22 due to the turning off of the gate pulse due to the gate-source capacitance Cgs of the TFT 21 is alleviated.

FIG. 7 shows the transmittance-viewing angle characteristics when the liquid crystal display device having the structure shown in FIGS. 1 to 5 is caused to perform 8-gradation display.
This characteristic is obtained when the area ratio of the normal pixel A1 and the voltage drop pixel A2 is 1: 1. For comparison, the transmittance of the liquid crystal display element in the conventional structure in which the pixel is not divided-
The viewing angle characteristics are shown in FIG. The horizontal axis in FIGS. 7 and 8 represents the viewing angle, 0 ° to 50 ° represents the upward angle, and 0 ° to −50.
° indicates a downward angle. The vertical axis represents the transmittance. Voltage V
1 to V8 represent applied voltages when performing 8-gradation display. V1 indicates a voltage for displaying light, V8 indicates a voltage for displaying dark, and the voltages V2 to V7 are values obtained by dividing the voltage V8 into seven equal parts.

In the characteristics shown in FIG. 8, the downward 30 ° to
At a viewing angle of 50 °, the transmittance for voltage V8 is
The transmittance is higher than V7 to V7, and the display gradation is inverted.

On the other hand, in the characteristics of FIG. 7, the transmittance for the voltage V8 is lower than the transmittance for the voltages V3 to V7 at the downward viewing angle of 30 ° to 50 °, and the inversion of the display gradation occurs. Absent. That is, the viewing angle is expanded in this embodiment.

As described above, in this embodiment, the color filter 33 and the overcoat layer 34 are provided on the counter substrate 12 side.
Is used to form the control capacitance CFC and the additional capacitances CS1 and CS2. Therefore, it is possible to realize a liquid crystal display device having a small voltage drop of the pixel electrode 22 due to the parasitic capacitance between the gate and the source of the TFT 21 and having a wide viewing angle. Further, since the electrodes for forming the control capacitance and the additional capacitance are formed on the side of the counter substrate 12, the TFT is manufactured in the process of manufacturing these electrodes.
It is possible to prevent the situation that the liquid crystal is destroyed and improve the manufacturing yield of the liquid crystal display element.

(Second Embodiment) FIG. 9 shows an enlarged cross section of one pixel of a liquid crystal display device according to a second embodiment of the present invention. In the configuration of this embodiment, the lower layer electrode 31 is formed on the counter substrate 12, and the first insulating film including the color filter 33 and the overcoat layer 34 is formed on the lower layer electrode 31. On the overcoat layer 34, upper layer electrodes 35a and 35b for dividing the pixel into two have an area ratio of 7: 3.
It is formed so as to be 5: 5. Upper layer electrode 35a
Is formed in a size smaller than the lower layer electrode 31 and is connected to the lower layer electrode 31 at the end. The upper layer electrode 35b is formed so that a part thereof faces the lower layer electrode 31. A second insulating film 39 is formed on the upper layer electrodes 35a and 35b, and an additional capacitance electrode 38 is formed in each pixel region on the second insulating film 39 so as to face a part of the upper layer electrode 35b. Has been done. The additional capacitance electrode 38 is connected to the opposing pixel electrode 22.

The equivalent circuit of the liquid crystal display device having such a configuration is the same as the equivalent circuit of the first embodiment shown in FIG.

Therefore, according to this embodiment as well, the TFT
It is possible to realize a liquid crystal display device having a wide viewing angle, which is less affected by the gate-source capacitance 21. In addition, the manufacturing yield of the liquid crystal display device can be improved.

(Third Embodiment) FIG. 10 shows a third embodiment of the present invention.
The cross section of 1 pixel of the liquid crystal display element of embodiment is expanded and shown. In the configuration of this embodiment, the upper layer electrode 35a and the lower layer electrode 31 are not connected, and the driving voltage V0 is equal to the upper layer electrode 35.
The configuration is the same as that of the first embodiment except that it is applied between a and the pixel electrode 22. In the configuration of FIG. 10, the capacitance between the upper layer electrode 35a and the pixel electrode 22 is CLC1, the capacitance between the upper layer electrode 35b and the pixel electrode 22 is CLC2, and the capacitance between the upper layer electrode 35a and the lower layer electrode 31 is CCF1. , The capacitance between the upper layer electrode 35a and the additional capacitance electrode 38 is CS1,
The capacitance between the upper layer electrode 35b and the lower layer electrode 31 is CCF2,
The capacitance between the upper layer electrode 35b and the additional capacitance electrode 38 is CS2
Then, the equivalent circuit of the liquid crystal display device having this configuration is shown in FIG.
It becomes as shown in. In such a configuration, the voltage applied to the liquid crystal 13 of the normal pixel A1 is expressed by Expression 3, and the voltage applied to the liquid crystal 13 of the voltage drop pixel A2 is expressed by Expression 4.

[0039]

[Equation 3] VLC1 = V0

[Equation 4] VLC2 = VLC1 × CCF / (CCF + CLC2 + CS2)

That is, the drive voltage V0 is applied to the liquid crystal 13 of the normal pixel A1 almost as it is, and a voltage obtained by dividing the drive voltage V0 is applied to the liquid crystal 13 of the voltage drop pixel A2.
Therefore, regions with different alignment states are formed in each pixel,
Since these optical characteristics are averaged, the viewing angle becomes wide.

The first additional capacitance CS1 is connected in parallel to the liquid crystal capacitance (first liquid crystal capacitance) CLC1 of the normal pixel A1, and the second additional capacitance CS2 is connected to the liquid crystal capacitance (second liquid crystal capacitance) CLC2 of the voltage drop pixel A2. Since they are connected in parallel, the influence of the gate-source capacitance of the TFT 21 can be suppressed.

(Fourth Embodiment) FIG. 12 shows a fourth embodiment of the present invention.
The cross section for 1 pixel of the liquid crystal display element of embodiment is expanded and shown. In this embodiment, the additional capacitance electrode 38 (lower layer electrode) is formed over the entire pixel region on the counter substrate 12. The additional capacitance electrode 38 is connected to the opposing pixel electrode 22. An insulating film 39 is formed on the additional capacitance electrode 38, and an intermediate layer electrode 40 having an area smaller than that of the additional capacitance electrode 38 is formed on the insulating film 39. A common voltage Vcom of the liquid crystal display element is applied to the middle layer electrode 40. A color filter 33 is formed in each pixel region on the intermediate electrode 40, and an overcoat layer 34 is further formed thereon. An upper layer electrode 35 is formed on the overcoat layer 34 so as to face the additional capacitance electrode 38 and partially face the middle layer electrode 40.

Each pixel has a region (voltage drop pixel) A2 in which the upper layer electrode 35 is arranged and another region (normal pixel) A1.
Is divided into The area ratio between the normal pixel A1 and the voltage drop pixel A2 is formed to be about 5: 5 to 7: 3. The first control capacitance between the middle layer electrode 40 and the boundary point (hereinafter, K1 point) between the overcoat layer 34 and the alignment film 36 is CCF1, K1.
The first liquid crystal capacitance between the point and the pixel electrode 22 is CLC1, and the first additional capacitance between the middle layer electrode 40 and the additional capacitance electrode 38 is CLC1.
S1, a second control capacitance between the middle electrode 40 and the upper electrode 35 is CCF2, a second liquid crystal capacitance between the upper electrode 35 and the pixel electrode 22 is CLC2, and a second liquid crystal capacitance between the upper electrode 35 and the additional capacitance electrode 38 is SLC. Assuming that the second additional capacitance is CS2 and the drive voltage V0 of the liquid crystal display element is applied between the middle layer electrode 40 and the pixel electrode 22, the equivalent circuit of each pixel is as shown in FIG.

From FIG. 13, the voltage VLC1 applied to the liquid crystal 13 of the normal pixel A1 and the voltage VLC2 applied to the liquid crystal 13 of the voltage drop pixel A2 are expressed by equations 5 and 6, respectively.

[0045]

[Formula 5] VLC1 = V0 × CCF1 / (CCF1 + CLC1)

[Equation 6] VLC2 = V0 × CCF2 / (CCF2 + CLC2 + CS2)

That is, the drive voltage V0 is applied to the liquid crystal 13 of the normal pixel A1 after being divided by the first control capacitance CCF1 and the first liquid crystal capacitance CLC1 and applied to the liquid crystal 13 of the voltage drop pixel A2. Is divided and applied to the second control capacitance CCF2 and the combined capacitance in which the second additional capacitance CS2 is connected in parallel to the second liquid crystal capacitance CLC2.

Therefore, by appropriately setting the value of each capacitance, different voltages can be applied to the normal pixel A1 and the voltage drop pixel A2 to widen the viewing angle. Also, the first
Since the compensation capacitances are connected to the liquid crystal capacitance CLC1 and the second liquid crystal capacitance CLC2, respectively, the influence of the parasitic capacitance of the TFT 21 can be further appropriately reduced.

The voltage VLC1 is the magnitude of the first control capacitor CCF1,
That is, by changing the thicknesses of the color filter 33 and the overcoat layer 34, they can be arbitrarily changed and adjusted. The voltage VLC2 is the size of the second control capacitance CCF2 and the additional capacitance CS2, that is, the thickness of the color filter 33 and the overcoat layer 34, or the middle layer electrode 40 and the upper layer electrode 35.
And the thickness of the insulating film 39, the color filter 33, and the overcoat layer 34, or the area of the facing portion of the additional capacitance electrode 38 and the upper layer electrode 35 are changed. , Can be adjusted. Therefore, similarly to the first embodiment, the conditions for obtaining the optimum voltages VLC1 and VLC2 are obtained in advance by experiments or the like, and each is arranged or formed according to the conditions.

The present invention is not limited to the above embodiment, and various modifications and applications are possible. For example, according to the above embodiment, each pixel is divided into two, but may be divided into three, four, six, and so on.

Further, the lower layer electrode 31, the additional capacitance electrode 38, the middle layer electrode 40 and the upper layer electrode 3 formed on the counter substrate 12 are formed.
The arrangement positions of 5a, 35b, the color filter 33, the overcoat layer 34, the insulating film 39, and the like may be appropriately changed.
Also, it may be omitted or added depending on the configuration. Also,
The additional capacitance electrode 38 may be made of metal or may be made of the black mask 32.

Further, although the present invention is applied to the color liquid crystal display device using the color filter in the above-described embodiment, it is also applicable to the liquid crystal display device for monochrome gradation display. In this case, instead of the color filter, an insulating film having a relative dielectric constant of 3.0 to 4.0 is formed to 1.0 to 2.0 μm, and the upper layer electrodes 35a and 35b are formed thereon.
With such a structure, it is possible to obtain a monochrome TN liquid crystal display element having a wide viewing angle.

The direction of the alignment treatment applied to the alignment films 23 and 36,
The twist angle of the liquid crystal 13 and the arrangement of the transmission axes of the polarizing plates 14 and 15 are not limited to those in the above embodiment, and can be arbitrarily changed. For example, the twist angle of the liquid crystal 13 is 180 ° to 27
It may be about 0 °. Further, the transmission axis of the polarizing plate 14 on the light incident side may be parallel to the alignment treatment of the lower alignment film 23.
Further, the transmission axis of the polarizing plate 15 on the light emitting side may be parallel to the transmission axis of the lower polarizing plate 14.

In the above embodiment, the present invention has been described by taking the TFT liquid crystal display element as an example. However, the present invention is not limited to this.
The present invention can be applied to a liquid crystal display device having an active element. Further, it is also applicable to a passive matrix type liquid crystal display element which does not use an active element. Further, the present invention is not limited to the transmissive liquid crystal display element, but can be applied to a reflective liquid crystal display element having a reflective film.

[0054]

As described above, it is possible to provide a liquid crystal display element which is hardly affected by the parasitic capacitance of the active element and has a wide viewing angle. In addition, since the control capacitor and the additional capacitor are formed by the insulating film on the second substrate side, the defect that the active element formed on the first substrate side is destroyed in the manufacturing process is reduced, and a liquid crystal display device with a high yield rate is obtained. Can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a color TN type liquid crystal display element according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of a TFT substrate.

FIG. 3 is a plan view showing a configuration of electrodes of a counter substrate.

FIG. 4 is a diagram showing definitions of a direction of alignment treatment and a twist direction of liquid crystal molecules.

FIG. 5 is a cross-sectional view showing a configuration of one pixel of the liquid crystal display element according to the first embodiment of the present invention.

FIG. 6 is a diagram showing an equivalent circuit of one pixel of the liquid crystal display element of the first embodiment.

FIG. 7 is a diagram showing the relationship between the viewing angle and the transmittance of the liquid crystal display element of the first embodiment.

FIG. 8 is a diagram showing a relationship between a viewing angle and a transmittance of a liquid crystal display element having a conventional structure.

FIG. 9 is a cross-sectional view showing the structure of one pixel of the liquid crystal display element of the second embodiment according to the present invention.

FIG. 10 is a cross-sectional view showing the configuration of one pixel of the liquid crystal display element of the third embodiment according to the present invention.

FIG. 11 is a diagram showing an equivalent circuit of one pixel of the liquid crystal display element of the third embodiment.

FIG. 12 is a cross-sectional view showing a configuration of one pixel of a liquid crystal display element according to a fourth embodiment of the present invention.

FIG. 13 is a diagram showing an equivalent circuit for one pixel of the liquid crystal display element of the fourth embodiment.

[Explanation of symbols]

11 ... TFT substrate, 12 ... counter substrate, 13 ... liquid crystal,
14 ... Polarizing plate, 15 ... Polarizing plate, 16 ... Liquid crystal cell, 2
1 ... TFT, 22 ... Pixel electrode, 23 ... Alignment film, 31 ...
.. Lower electrode, 32 ... Black mask, 33 ... Color filter, 34 ... Overcoat layer, 35, 35a, 3
5b ... upper layer electrode, 36 ... alignment film, 37 ... electrode terminal,
38 ... Additional capacitance electrode, 39 ... Insulating film, 40 ... Middle layer electrode, SC ... Sealing material, GL ... Gate line, DL ...
Data line, A1 ... Normal pixel, A2 ... Voltage drop pixel

Claims (6)

[Claims] 1. A first substrate in which a first electrode is formed in each pixel region and an active element connected to the corresponding first electrode is formed; and a first substrate facing the first substrate. A second substrate arranged, a second electrode formed in a part of each pixel region on a surface of the second substrate facing the first substrate, and formed on the second electrode An insulating film, a third electrode formed on a part of each pixel region on the insulating film, the third electrode being connected to the second electrode and facing the first electrode; A fourth electrode formed in a part of each pixel region above the second electrode so as to partly face the second electrode and face the first electrode; and each pixel region on the second substrate. A fifth electrode connected to the first electrode facing each other and formed to face the third electrode and the fourth electrode, And a liquid crystal sealed between the first substrate and the second substrate. 2. A first substrate on which a first electrode is formed in each pixel region and an active element connected to the corresponding first electrode is formed, and facing the first substrate. A disposed second substrate, and a second electrode formed in a part of each pixel region of a surface of the second substrate facing the first substrate, the second electrode facing the first electrode. A first insulating film formed on the second electrode, and a part of each pixel region on the first insulating film connected to the second electrode and the first electrode. A third electrode formed to face each other, and a part of each pixel region on the first insulating film to face the second electrode and to face the first electrode. The formed fourth electrode, the second insulating film formed on the third and fourth electrodes, and the second insulating film formed on a part of each pixel region on the second insulating film. A fifth electrode formed to face the third electrode and the fourth electrode and connected to the first electrode that faces the third electrode; and a liquid crystal sealed between the first and second substrates, A liquid crystal display device comprising: 3. A first substrate on which a first electrode is formed in each pixel region and an active element connected to the corresponding first electrode is formed, and facing the first substrate. A second substrate arranged, a second electrode formed in a part of each pixel region on a surface of the second substrate facing the first substrate, and formed on the second electrode An insulating film, a third electrode formed on a part of each pixel region on the insulating film so as to face the first electrode, and a part of the second electrode on the insulating film. And a fourth electrode formed to face the first electrode, and a part of each pixel region on the second substrate connected to the first electrode that faces the A fifth electrode formed so as to face the third electrode and the fourth electrode; and a liquid crystal sealed between the first and second substrates. Liquid crystal display device characterized by. 4. A first substrate in which a first electrode is formed in each pixel region and an active element connected to the corresponding first electrode is formed, and the first substrate is opposed to the first substrate. A second substrate arranged, a second electrode formed in each pixel region on a surface of the second substrate facing the first substrate, and connected to the first electrode facing the second substrate, A first insulating film formed on a second electrode, and formed on a part of each pixel region on the first insulating film, and formed so as to face the first and second electrodes. A third electrode, a second insulating film formed on the third electrode, a part of each pixel region on the second insulating film, and the first to third electrodes A liquid crystal display device, comprising: a fourth electrode facing the first substrate; and a liquid crystal sealed between the first and second substrates. 5. The insulating film, the first insulating film, and the second insulating film each include at least one of a color filter and an overcoat layer. 1. The liquid crystal display element according to item 1. 6. The insulating film, the first insulating film, and the second insulating film have a relative permittivity of 3.0 to 4.0 and a thickness of 1.0 to 2.0 μm, respectively. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is a liquid crystal display element.