JP2001235752A - Multi-domain liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-domain liquid crystal display device having high contrast and excellent in a visual angle characteristic, without increasing complex processes such as micro-fabrication process of a common electrode, and requiring a high degree of sticking technology. SOLUTION: In the multi-domain liquid crystal display device a control electrode 73 is connected with a source terminal 57 which is one of the terminals of a TFT 54 as a switching element, and a pixel electrode 71 with an opening part 74 formed therein has coupling capacitance 126 across the control electrode 73, and a divided signal voltage is applied to the pixel electrode 71 via the coupling capacitance 126.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-domain liquid crystal display device, and more particularly, to a multi-domain liquid crystal display device having excellent viewing angle characteristics.

[0002]

2. Description of the Related Art Twisted Nematic (hereinafter referred to as "TN") has been widely used.
In the liquid crystal display device of the type, the liquid crystal molecules are twisted parallel to the substrate surface, and the liquid crystal molecules change in the direction of the electric field from the "white" display state when no voltage is applied. By changing the direction, the display state gradually changes from the “white” display state to the “black” display state.
However, due to the behavior of the liquid crystal molecules due to this voltage application, T
There is a problem that the viewing angle of the N-type liquid crystal display device is narrow. The problem that the viewing angle is narrow is particularly significant in the rising direction of the liquid crystal molecules in halftone display.

As a method for improving the viewing characteristics of a liquid crystal display device, a technique as disclosed in Japanese Patent Application Laid-Open No. 6-43461 has been proposed. FIG. 47 is a schematic partial cross-sectional view illustrating an example of the configuration of a liquid crystal display device according to the technology disclosed in the publication. According to this technique, a liquid crystal cell in which liquid crystal 21 having negative dielectric anisotropy is homeotropically (vertically) oriented is prepared, and two polarizing plates (not shown) arranged so that polarization axes are orthogonal to each other are prepared. By using the common electrode 81 having the opening 74 therebetween, the electric field is obliquely concentrated in each pixel, thereby making each pixel two or more domains, so-called multi-domain, and improving the viewing angle characteristics. ing. In this technique, an optical compensator may be used as necessary to improve the black viewing angle characteristics. Further, not only in the liquid crystal cell with homeotropic alignment but also in the cell with TN alignment, by using a common electrode having an opening, an oblique electric field is generated to divide each pixel into two or more domains. And has improved viewing angle characteristics.

In the technique disclosed in Japanese Patent Application Laid-Open No. 7-199190, an opening (alignment control window) is provided in a common electrode, and an alignment control electrode is provided so as to surround a pixel electrode. The liquid crystal domain is stabilized by emphasizing the oblique electric field in the liquid crystal.

In addition, in Japanese Patent Application Laid-Open No. 7-230097, an alignment control electrode integrated with a gate line is provided on a pixel electrode, and each pixel is formed into two or more liquid crystal domains by an oblique electric field from the alignment control electrode. The viewing angle characteristics have been improved.

The technique disclosed in Japanese Patent Application Laid-Open No. 10-20323 discloses a technique of forming a plurality of liquid crystal domains by providing an opening in a pixel electrode and disposing a control electrode at the position of the opening. Has been disclosed.

Japanese Patent Application Laid-Open No. 10-301114 discloses a liquid crystal cell in which a liquid crystal having a negative dielectric constant is homeotropically aligned, and a projection is provided on an alignment film. Techniques have been devised for controlling and operating by dividing into two or more liquid crystal domains.

[0008]

However, among these techniques, in the technique disclosed in Japanese Patent Laid-Open No. 6-43461, which has an opening in a common electrode,
In addition to the necessity of a “fine processing step such as a photoresist step for a common electrode”, which is not required in a normal manufacturing process of a mono-domain type TN type liquid crystal display device,
There is a problem that an advanced bonding technique of the upper and lower substrates is required. This problem is caused by the thin film transistor (ThinF).
In the case of an active matrix liquid crystal display device using a switching element such as an ilmTransistor (TFT), this is a particularly serious problem. That is, in a normal active matrix liquid crystal display device, one of the transparent substrates (TF
In order to manufacture a switching element (active element) such as a thin film transistor on a T substrate), a fine processing step such as a photoresist step is required only on one TFT substrate on which the switching element is manufactured. The other electrode on the side of the transparent substrate (counter substrate) called "common electrode" does not need to be subjected to fine processing, and only the common electrode is formed on the entire surface. However, in the prior art having an opening in the common electrode, a fine processing step such as a photoresist step is required for the `` common electrode '' which does not normally require fine processing, and the number of steps increases. Advanced bonding technology for the upper and lower substrates will be required.

Due to such a problem, for example, an opening or a slit is provided in a pixel electrode on the side of a TFT substrate on which a switching element such as a TFT is formed, and an oblique electric field is generated to control the alignment of liquid crystal. Technology comes up. This is because the pixel electrode on the TFT substrate side originally requires patterning, and in this case, no additional step is required. However, stable liquid crystal domains cannot be controlled in this configuration. This is because the inclination of the electric field around the opening when the opening is provided in the common electrode as in JP-A-6-43461 matches the inclination direction of the electric field around the pixel electrode (FIG. 47).
On the other hand, when an opening is provided in the pixel electrode on the TFT substrate side, the inclination of the electric field around the opening does not match the inclination direction of the electric field around the pixel electrode.

As disclosed in JP-A-7-199190, when the control electrode is provided around the pixel electrode, the gradient of the electric field around the pixel electrode can be enhanced. In addition, an opening must be provided in the common electrode on the opposite substrate, and the above-described problem needs to be solved.

On the other hand, as described in JP-A-7-230097, an oblique electric field can be generated by arranging a control electrode on a pixel electrode and appropriately setting the potential of the control electrode. However, during so-called inversion driving in which the polarity of the pixel electrode potential is inverted at a constant cycle, the state of generation of the oblique electric field changes due to the change in the polarity of the pixel electrode potential, and thus stable and reliable control of the liquid crystal domain cannot be performed. Further, in this configuration, since the control electrode is integrated with the gate bus line, the control electrode potential cannot be changed according to the lighting / non-lighting of the pixel, that is, when the pixel is not lit (dark display). At times, an electric field in an oblique direction is generated in the control electrode potential, and this electric field causes light leakage around the control electrode, leading to a decrease in display contrast. If a light-shielding layer is provided to shield this light leakage, the aperture ratio will be significantly reduced. Further, normally, a DC voltage is applied to the common electrode in the gate bus line during a period excluding the selection period, so that when the control electrode is integrated with the gate bus line, the display area is The DC voltage is continuously applied to the liquid crystal layer inside the liquid crystal display, which causes a problem of deteriorating the reliability of the display element.

In the technique disclosed in Japanese Patent Application Laid-Open No. 10-20323, in which an opening is provided in a pixel electrode and a control electrode is arranged at that position, means for controlling the control electrode potential for each pixel during a display operation is also provided. Is not disclosed in JP-A-7-2
Similar to the technique described in Japanese Patent No. 30097, there is a problem that stable and reliable control of the liquid crystal domain cannot be performed.

As means for solving the above-mentioned problems in the techniques described in JP-A-7-230097 and JP-A-10-20323, for example, a control electrode individually provided for each pixel is used. Although a method of controlling with individual switching elements provided in each pixel is conceivable, in this configuration, it is necessary to provide individual switching elements and drain bus lines corresponding to the pixel electrodes and the control electrodes, Therefore, the element configuration becomes complicated, which is not practical in terms of manufacturing cost and manufacturing yield.

In the method of providing projections on an alignment film as described in JP-A-10-301114, the effect of region division by the projections works only in the vicinity of the projections. Therefore, in order to realize reliable area division, projections must be provided not only on the alignment film of the TFT substrate on one side where the switching elements are formed, but also on the alignment film of the counter substrate side. However, there has been a problem that the number of substrates has increased and that accurate bonding of both substrates is required.

The present invention has been made in view of the above circumstances, and has the problems of the prior art described above, that is, an increase in the number of complicated steps such as a fine processing step of a common electrode, and an advanced bonding technique. It is an object of the present invention to provide a multi-domain liquid crystal display device having high contrast and excellent viewing angle characteristics without requiring the following.

[0016]

According to a first aspect of the present invention, a liquid crystal sandwiched between a pair of substrates and a plurality of liquid crystals formed on one side of the substrates and extending in a lateral direction are provided. A plurality of pixels are arranged in a matrix corresponding to each of intersections of the gate bus lines and the drain bus lines. Each of which includes a switching element, a pixel electrode, and a control electrode for generating an electric field in an oblique direction with respect to the liquid crystal to form a plurality of alignment regions in one pixel. The control electrode is connected to one terminal of the switching element; the pixel electrode has a coupling capacitance with the control electrode; and the control electrode has a corresponding gate bus line. When selecting a signal, a signal voltage is applied from the corresponding drain bus line via the corresponding switching element, and a divided voltage of the signal voltage is applied to the pixel electrode via the coupling capacitance. I have.

According to a second aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the first aspect, wherein the pixel electrode and the control electrode are arranged below the pixel electrode via an insulating film. It is characterized by being.

According to a third aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the first or second aspect, wherein an opening is formed in the pixel electrode.

According to a fourth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the third aspect, wherein the control electrode applies an electric field for controlling the alignment state of the liquid crystal from the opening. I have.

According to a fifth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to any one of the first to fourth aspects, further comprising a common capacitance line for adding a capacitance to the pixel electrode. It is characterized by:

According to a sixth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the fifth aspect, wherein the common capacitance line is disposed at a position corresponding to the opening.

According to a seventh aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the fifth or sixth aspect, wherein a predetermined additional capacitance is provided between the pixel electrode and the common capacitance line. It is characterized by:

The invention according to claim 8 relates to the multi-domain liquid crystal display device according to any one of claims 1 to 7, wherein at least a part of the control electrode comprises a transparent electrode. .

According to a ninth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the eighth aspect, wherein the control electrode has quarter-wave plates on both sides of the liquid crystal layer. It is characterized in that the quarter-wave plates are arranged such that the optical axes are orthogonal to each other.

The invention according to claim 10 is the first invention.
According to the multi-domain liquid crystal display device described above, each of the liquid crystal has a quarter-wave plate on both sides, and the optical axes of the quarter-wave plate are arranged to be orthogonal to each other. Features.

The invention according to claim 11 is the first invention.
In the multi-domain liquid crystal display device according to any one of Items 1 to 10, the switching element is a bottom-gate TFT.

The invention according to claim 12 is the first invention.
The multi-domain liquid crystal display device according to any one of Items 1 to 10, wherein the switching element is a TFT having a top gate structure.

Further, the invention of claim 13 provides the invention of claim 1
13. The multi-domain liquid crystal display device according to 1 or 12,
The invention is characterized in that the insulating film is formed integrally with an insulating film for protecting the TFT.

The invention according to claim 14 is the first invention.
According to the multi-domain liquid crystal display device described in 2 or 13,
The invention is characterized in that the control electrode is formed integrally with a source terminal of the TFT.

The invention according to claim 15 is the same as the invention according to claim 3.
In the multi-domain liquid crystal display device described above, the opening is formed in a window shape.

The invention according to claim 16 is the third invention.
According to the multi-domain liquid crystal display device described above, the opening is formed so as to cut out from one side or both sides of the pixel electrode.

Further, the invention according to claim 17 is the same as the claim 1.
According to the multi-domain liquid crystal display device described above, a resistance element for discharging electric charges accumulated in the pixel electrode is provided between the pixel electrode and the control electrode.

The invention according to claim 18 is the first invention.
7. The multi-domain liquid crystal display device according to 7, wherein the resistance element has a substantially finite resistance value.

The invention according to claim 19 is the invention according to claim 5
In the multi-domain liquid crystal display device described above, a resistive element having a substantially finite resistance value is provided between the pixel electrode and the common capacitance line.

The invention according to claim 20 is the first invention.
According to the multi-domain liquid crystal display device described above, the operation mode of the liquid crystal is a TN mode in which liquid crystal having a positive dielectric anisotropy is twisted.

Further, the invention described in claim 21 is based on claim 2
0, wherein the liquid crystal is spontaneous chiral.

The invention according to claim 22 is based on claim 2
0, wherein the liquid crystal is involuntary chiral.

[0038] The invention according to claim 23 is based on claim 1.
According to the multi-domain liquid crystal display device described above, the operation mode of the liquid crystal is a homogeneous mode in which liquid crystal having a positive dielectric anisotropy is uniformly aligned.

The invention according to claim 24 is the first invention.
According to the multi-domain liquid crystal display device described above, the operation mode of the liquid crystal is a VA mode in which a liquid crystal having a negative dielectric anisotropy is homeotropically (vertically) aligned.

According to a twenty-fifth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the first, second or third aspect, wherein the pixel electrode is formed of a plurality of square pixel electrodes. Control electrodes are arranged along the sides, and the remaining three sides are openings or pixel electrode ends.

According to a twenty-sixth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the first, second or third aspect, wherein the pixel electrode is formed by a plurality of small pixel electrodes having a rectangular shape. Control electrodes are arranged along the sides, and the remaining two sides are openings or pixel electrode ends.

The invention according to claim 27 is based on claim 2
According to the multi-domain liquid crystal display device described in 5 or 26,
The quadrilateral is characterized by being formed of a substantially square.

According to a twenty-eighth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the first, second or third aspect, wherein the pixel electrode is formed of a plurality of minute pixel electrodes each comprising a triangle. The control electrode is arranged along two sides of the above, and the remaining one side is an opening or a pixel electrode end opening.

According to a twenty-ninth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the first, second, or third aspect, wherein the pixel electrode is formed of a plurality of small pixel electrodes comprising a triangle. Is characterized in that the control electrodes are arranged along one side, and the remaining two sides are openings or pixel electrode end openings.

According to a thirtieth aspect of the present invention, there is provided the multi-domain liquid crystal display device according to the first, second or third aspect, wherein the pixel electrode is formed of a plurality of pentagonal minute pixel electrodes. The control electrodes are arranged along the two sides, and the remaining three sides are openings or pixel electrode end openings.

The invention according to claim 31 relates to the multi-domain liquid crystal display device according to claim 1, 2 or 3, wherein the pixel electrode is formed of a plurality of minute pixel electrodes, and the minute pixel electrode is It is characterized in that two or more kinds of the minute pixel electrodes according to any one of claims 25 to 30 are combined.

The invention according to claim 32 is directed to claim 2
7. The multi-domain liquid crystal display device according to 7, wherein a ratio of a control electrode voltage applied to the control electrode to a pixel electrode voltage applied to the pixel electrode is 1.1 to 1. 4 is set.

The invention described in claim 33 is the invention according to claim 32.
In the multi-domain liquid crystal display device described above, a ratio of the electrode voltage to the pixel electrode voltage is set to 1.2 to 1.4.

The invention according to claim 34 is the third invention.
3. The multi-domain display device according to item 3, wherein a ratio of the control electrode voltage to the pixel electrode voltage is set to approximately 1.3.

The invention according to claim 35 is the second invention.
7. The multi-domain liquid crystal display device according to item 7, wherein the size of the micro-alignment region in which the liquid crystal is substantially aligned is approximately 20 μm square or less.

The invention according to claim 36 is based on claim 2
7. The multi-domain liquid crystal display device according to item 7, wherein the size of the micro-alignment region in which the liquid crystal is substantially aligned is approximately 40 μm square or more.

The invention described in claim 37 is based on claim 2
7. The multi-domain liquid crystal display device according to item 7, wherein the size of the micro-alignment region in which the liquid crystal has a substantially single alignment is 20 to 40 μm
It is characterized by being m square.

The invention according to claim 38 is the first invention.
13. The multi-domain liquid crystal display device according to 1 or 12,
By overlapping a coupling capacitance terminal electrically connected to one of the pixel electrode and the control electrode with the other electrode to which the coupling capacitance terminal is not connected via a gate insulating film, It is characterized by constituting at least a part of the coupling capacitance.

The invention according to claim 39 is the same as that in claim 7.
According to the multi-domain liquid crystal display device described above, an additional capacitance terminal electrically connected to one of the pixel electrode or the common capacitance line, and the other one of the additional capacitance terminal is not connected, a protective insulating film It is characterized in that at least a part of the additional capacitance is constituted by superimposing via the intermediary.

The invention according to claim 40 provides the invention according to claim 7.
According to the multi-domain liquid crystal display device described above, an additional capacitance terminal electrically connected to one of the pixel electrode or the common capacitance line, and the other one of the additional capacitance terminal is not connected, a gate insulating film It is characterized in that at least a part of the additional capacitance is constituted by superimposing via the intermediary.

The invention according to claim 41 is the first invention.
According to the multi-domain liquid crystal display device described above, a discharge element for discharging the electric charge accumulated in the pixel electrode is disposed on a gate bus line corresponding to a stage preceding an arbitrary pixel.

Further, the invention according to claim 42 is the same as claim 4
1. In the multi-domain liquid crystal display device according to 1, the protective insulating film is removed from a portion of the opening provided in the pixel electrode, the portion corresponding to the opening on which a control electric field from a control electrode disposed in a lower layer acts. It is characterized by:

The invention according to claim 43 has a liquid crystal sandwiched between a pair of substrates, and a plurality of pixels arranged in a matrix on one side of the substrates, and each of the pixels has The present invention relates to a multi-domain liquid crystal display device comprising: a switching element; a pixel electrode; and a control electrode for generating an electric field in an oblique direction with respect to the liquid crystal to form a plurality of alignment regions in one pixel. Is connected to one terminal of the switching element, the pixel electrode has a coupling capacitance with the control electrode, a signal voltage is applied to the control electrode via the corresponding switching element, A partial voltage of the signal voltage is applied to the pixel electrode via the coupling capacitor.

[0059]

Embodiments of the present invention will be described below with reference to the drawings. The description will be specifically made using an embodiment. First Embodiment FIG. 1 is a schematic plan view showing a configuration of a pixel (repeating unit) of a multi-domain liquid crystal display device according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram taken along line AA ′ of FIG. FIG. 3 is a schematic partial sectional view taken along line BB ′ of FIG.
4 is a schematic partial cross-sectional view taken along the line CC ′ of FIG. 1, FIG. 5 is an equivalent circuit diagram of a pixel of the multi-domain liquid crystal display device, and FIGS. 6 and 7 are manufacturing methods of the multi-domain liquid crystal display device. FIG. The multi-domain liquid crystal display device of this example has, as shown in FIGS.
One pixel is constituted by a unit of a region surrounded by a plurality of gate bus lines 55 extending in the horizontal direction and a plurality of drain bus lines 56 extending in the vertical direction. Each pixel is formed on the first substrate 11. , Arranged in a matrix in the up, down, left, and right directions.

Each pixel has a TFT 54, a pixel electrode 71, and a control electrode 73. The TFT 54 has a bottom gate structure in which a gate is disposed below a source and a drain, and amorphous silicon or polysilicon can be used as an active layer (semiconductor layer). Can be. The pixel electrode 71 is electrically floating, and the control electrode 73
And the coupling capacitance 126 and the additional capacitance 12 via the common capacitance line 72 and the interlayer insulating film 63 and the gate insulating film 61, respectively.
7 are formed. The TFT 54 is covered with a protective insulating film 65. Silicon nitride or the like is used for the interlayer insulating film 63, the gate insulating film 61, and the protective insulating film 65. Here, the common capacitance line 72 is provided to add capacitance to the pixel electrode 71.

The capacitance of the coupling capacitor 126 and the capacitance of the additional capacitor 127 can be set to desired values by parameters such as the material, size and thickness of the interlayer insulating film 63 and the gate insulating film 61. The pixel electrode 71 and the control electrode 73 are formed of transparent electrodes, and are made of a material such as ITO (Indium Tin Oxide). The control electrode 73 is connected to the source terminal 57 of the TFT 54. The control electrode 73 is a TFT5
4 can be formed integrally with the source terminal.
For the gate bus line 55, the source terminal 57, the drain terminal 58, and the common capacitance line 72, a metal film such as chromium is used. A common electrode 81 is formed on the second substrate 12 and is superposed on the first substrate 11 at a predetermined interval. A liquid crystal 20 is sandwiched between the substrates 11 and 12. Although the TFT 54 is shown as a bottom gate structure, it may have a top gate structure in which the gate is located above the source and drain, as in a fifth embodiment described later.

In this example, a common capacitance line 72 for adding a capacitance to the pixel electrode 71 is provided, but the coupling between the pixel electrode 71 and the control electrode 73 in FIG. If the necessary potential difference is obtained between the capacitor 126 and the liquid crystal capacitor 125 between the pixel electrode 71 and the common electrode 81, it is not necessary to particularly provide the common capacitor line 72.

In this example, the gate bus line 55
Is selected from the drain bus line 56 at the moment
The signal voltage is written to the control electrode 73 connected to the source terminal 57 via T54. At this time, the potential of the floating pixel electrode 71 is determined at a predetermined potential between the control electrode 73 and the common capacitance line 72 according to the capacitance ratio of the coupling capacitance 126 to the additional capacitance 127 and the liquid crystal capacitance 125. The common capacitance line 72 is, for example, the second substrate 1
It may be configured to have the same potential as the common electrode 81 on the second, or may be connected to a gate bus line or the like in the preceding stage. In this example, the control electrode 73, the pixel electrode 71,
Since the relationship of the potential of the common electrode 81 is in the order of this list or in the reverse order, the pixel electrode 71 and the control electrode 73 are
As shown in FIG. 3, the liquid crystal driving electric field E1 generated between the common electrode 81 and the common electrode 81 is generated obliquely so as to spread outward from the control electrode 73.

Hereinafter, VA (Vertical Align) in which a liquid crystal having a negative dielectric anisotropy is homeotropically aligned.
The operation will be described by taking the case of the (ment) mode as an example. The alignment state of the liquid crystal 20 (or the liquid crystal molecules 21) interposed between the first substrate 11 and the second substrate 12 is changed by the liquid crystal driving electric field E1. In this example, since the liquid crystal driving electric field E1 is generated so as to spread outward from the control electrode 73 as described above, the liquid crystal molecules 21 move in different directions on both sides of the control electrode 73 as shown in FIGS. Change the orientation direction. Therefore, the liquid crystal molecules 21
The regions (liquid crystal domains) having different inclination directions compensate the viewing angle characteristics with each other, and as a whole, a favorable viewing angle characteristic can be obtained. In this description, for convenience, the liquid crystal viewed in bulk is referred to as liquid crystal 20, and the individual liquid crystal molecules are referred to as liquid crystal molecules 21, but this difference is not so important in the present invention.

As described above, in this example, the liquid crystal 20
Has been described in the case of the VA mode in which a liquid crystal having a negative dielectric anisotropy is homeotropically aligned. In addition, the liquid crystal having a positive dielectric anisotropy is twisted and aligned. A TN mode or a homogeneous mode in which liquid crystals having positive dielectric anisotropy are uniformly aligned may be used. T
In the case of the N mode, the liquid crystal may have a spontaneous chiral property or a non-spontaneous chiral property. In the case of the non-spontaneous chiral property, the liquid crystal driving electric field E <b> 1 can be operated by being divided into a plurality of regions having different chiral directions. In order to stabilize the liquid crystal domain, it is possible to mix a polymer compound with the liquid crystal. In addition, a domain can be stabilized by adding a monomer to the liquid crystal to form a domain and then polymerizing the domain.

As shown in FIG. 4, by providing an appropriate opening 74 in the pixel electrode 71, the formation of the liquid crystal domain can be further ensured. The opening 74 may be formed in a window shape or may be formed so as to cut out from one side or both sides of the pixel electrode 71. Of course, the opening 7
The object of the present invention can be achieved without providing 4. It is also possible to provide a color layer (not shown) or a light shielding layer (not shown) on the first substrate 11 or the second substrate 12 as in a fourth embodiment described later. Note that a part or the whole of the common capacitance line 72 may be formed of a transparent electrode.

Next, with reference to FIGS. 6 and 7, a method of manufacturing the multi-domain liquid crystal display device of this embodiment will be described in the order of steps. First, as shown in FIG. 6A, chromium is sputter-deposited on the entire surface of the first substrate 11 made of glass, and the chromium is patterned into a desired shape using a photolithography technique. 55 and the common capacitance line 72 were formed. Subsequently, the CVD (Ch
The gate insulating film 6 is formed by forming silicon nitride on the entire surface by an electrical vapor deposition (CVD) method.
1 was formed.

Next, as shown in FIG. 6B, after an amorphous silicon film was formed on the entire surface by the CVD method, the active layer 64 was formed by patterning the amorphous silicon into a desired shape by a photolithography technique. Next, after chromium was formed on the entire surface by sputtering, chromium was patterned into a desired shape by a photolithography technique to form a drain bus line 56, a drain terminal 58, and a source terminal 57. Next, after ITO is formed on the entire surface by sputtering, ITO is formed by photolithography technology.
Was patterned into a desired shape to form a pixel electrode 71 having an opening 74. This pixel electrode 71 becomes floating as described above. As described above, the TFT 54 was formed on the first substrate 11.

Next, as shown in FIG. 7C, after a silicon nitride film is formed on the entire surface by the CVD method, the silicon nitride is patterned into a desired shape by a photolithography technique to form an interlayer insulating film 63 and a TFT 54. And a contact hole 59 was formed so that the source terminal 57 was exposed. In this case, the interlayer insulating film 63 and the protective insulating film 65 may be formed so as to be integrated. Next, after forming ITO by sputtering on the entire surface, the control electrode 73 was formed by patterning the ITO into a desired shape by a photolithography technique. The control electrode 73 is connected to the source terminal 57 via the contact hole 59.

Next, as shown in FIG. 7D, R (Re) is formed on a second substrate 12 made of glass by a printing method or the like.
d), G (Green), B (Black) color layers and a black matrix (not shown) are formed, and I
After the TO film was formed by sputtering, the common electrode 81 was formed by patterning the ITO into a desired shape by a photolithography technique.

The first substrate 11 prepared as described above
An alignment film (not shown) for vertical alignment was formed on each of the second substrate 12 and the second substrate 12. As an alignment film material, SE-1211 manufactured by Nissan Chemical Industries, Ltd. was used. Next, the first substrate 11
A sealing material (not shown) is applied linearly on the upper surface, and a spherical spacer (not shown) is sprayed on the second substrate 12, the substrates 11 and 12 are attached to each other, and the sealing material is heated. Cured. Next, after the structure in which the first substrate 11 and the second substrate 12 are integrated by the sealing material is cut into individual panel shapes, a nematic liquid crystal having a negative dielectric anisotropy is injected from the injection hole. After the injection, the injection hole was sealed with a photocurable resin. Next, after attaching a negative compensation film to both sides of the panel, a polarizing plate is further attached to both sides so that transmission axes thereof are orthogonal to each other, and a peripheral driving circuit is attached to make a module. As shown in the
The multi-domain liquid crystal display device of this example was completed.

FIG. 1 shows the planar shape of each component of the multi-domain liquid crystal display device manufactured by the above-described manufacturing method, and the size of the pixel is approximately 100 μm × 300 μm. The planar shape of each component is not limited to the shape shown in FIG. 1, but various shapes can be considered as shown in FIG. 20 described later.

In the multi-domain liquid crystal display device of this example, when the polarizing plates are arranged so that their transmission axes are perpendicular to each other, in each of the main liquid crystal alignment regions, the tilt direction of the liquid crystal molecules 21 is set on both sides. Since the transmission axis coincides with the direction that bisects the transmission axis, that is, the upper, lower, left, and right directions, a good bright state can be displayed by applying the liquid crystal driving electric field E1. May occur. The cause of the dark line is described in the second section below.
An example will be described. When the occurrence of dark lines is a problem, an optically anisotropic medium called a quarter-wave plate is inserted between the polarizing plate and the liquid crystal 20 so that circular polarization enters the liquid crystal layer. With this configuration, it is possible to eliminate the occurrence of dark lines. In this case, the control electrode 73 may be formed of a transparent electrode.

As described above, according to the multi-domain liquid crystal display device of this example, the control electrode 73 is connected to the source terminal 57 which is one terminal of the TFT 54 serving as a switching element, and the pixel in which the opening 74 is formed. The electrode 71 has a coupling capacitance 126 between itself and the control electrode 73, and the pixel electrode 71
To the control electrode 73 and the pixel electrode 71 during operation.
The liquid crystal can be divided into a plurality of regions and operated by the action of an oblique electric field generated in the periphery of the liquid crystal. Therefore, it is possible to provide a multi-domain liquid crystal display device with high contrast and excellent viewing angle characteristics without increasing the number of complicated steps such as the fine processing step of the common electrode and without requiring an advanced bonding technique.

Second Embodiment FIG. 8 is a schematic plan view showing the configuration of a multi-domain liquid crystal display device according to a second embodiment of the present invention, and FIG.
FIG. 10 is a schematic partial cross-sectional view taken along line D-D ′ of FIG.
It is a typical fragmentary sectional view in E '. The configuration of the multi-domain liquid crystal display device of this example is significantly different from the configuration of the first embodiment described above in that the control electrode is formed below the pixel electrode via an interlayer insulating film. It is. That is, as shown in FIGS. 8 to 10, the multi-domain liquid crystal display device of this example has a first substrate 1
Pixels (the structure shown in FIG. 8) are repeatedly arranged in a matrix in the vertical, horizontal, and horizontal directions, and a control electrode 73 made of ITO or the like is interposed via an interlayer insulating film 63 made of silicon nitride or the like. Are formed below the pixel electrode 71 made of ITO or the like. The pixel electrode 71 is floating as in the first embodiment. Control electrode 73
Can be formed integrally with the source terminal 57 of the TFT 54, which is advantageous in the manufacturing process.
Usually, since the source terminal 57 is formed of an opaque metal such as chromium as described above, the disadvantage that the light transmittance of the element is reduced is inevitable. On the other hand, when the control electrode 73 is made of a transparent electrode such as ITO as described above, as shown in FIG. 8, for example, the overlapping portion of the control electrode 73 and the pixel electrode 71 is set so that the capacitance value of the coupling capacitor 126 becomes sufficiently large. , A sufficient aperture ratio can be ensured.

In this example, as described above, the control electrode 73
Is located below the pixel electrode 71, the pixel electrode 71 is provided with an opening 74, and the electric field from the control electrode 73 acts on the liquid crystal through the opening 74, so that the liquid crystal is divided into a plurality of regions. Can be operated. Further, similarly to the first embodiment, the present invention can be applied not only to the bottom gate structure but also to the top gate structure. Other than this, it is substantially the same as the first embodiment described above. Therefore, in FIG. 8 to FIG. 10, the same parts as those in FIG. 1 to FIG.

The opening 74 of the pixel electrode 71 in this example
As in the first embodiment, the pixel electrode 71 may be formed in a window shape or may be formed so as to cut out from one side or both sides of the pixel electrode 71. By providing an appropriate opening 74 in the pixel electrode 71 in addition to the portion where the electric field from the control electrode 73 is applied, it is possible to more reliably form the liquid crystal domain. At the opening 74 where the electric field from the control electrode 73 acts, the liquid crystal driving electric field E1 acts so as to spread from the opening 74. However, when the control electrode 73 does not exist at the opening 74, or FIG.
When the common capacitance line 72 exists in the opening 74 as shown in FIG. 19, the liquid crystal driving electric field E1 acts so as to converge on the center of the width of the opening 74.

FIG. 11 is a diagram schematically showing a multi-domain liquid crystal alignment in this example, and shows an alignment state of a portion including the pixel electrode 71 and the control electrode 73 in FIG. As shown in FIG. 11, regions in which the tilt direction of the liquid crystal molecules 21 are different from each other are formed with the opening 74 of the pixel electrode 71 as a boundary. The azimuth is continuously changing.

In this example, a deflecting plate is arranged outside each of the first substrate 11 and the second substrate. Various combinations of the transmission axis directions of the deflection plates on both sides are possible, but among them, the transmission axes of the deflection plates on both sides are orthogonal to each other, and
By arranging the liquid crystal molecules 21 in the main liquid crystal alignment region so that the tilt direction of the liquid crystal molecules 21 coincides with the direction that bisects the orthogonal transmission axis of the polarizing plate, a bright and high-contrast display can be realized. Further, by inserting an optical compensator of a type having a larger in-plane refractive index, called a negative compensator, than the refractive index in the surface normal direction between the liquid crystal and the deflecting plate, the black compensating plate can be displayed. Can be improved in viewing angle characteristics.

FIG. 12 schematically shows the state of transmitted light corresponding to the multi-domain alignment state in this example. As in FIG. 11, the pixel electrode 71 shown in FIG.
And the state of transmitted light in a portion including the control electrode 73. Here, although the pixel electrode 71 and the control electrode 73 are transparent electrodes, the common capacitance line 72 is usually formed of an opaque metal such as chrome as described above. Although the light does not actually transmit, the light shielding by the common capacitance line 72 is ignored to explain the relationship between the liquid crystal alignment state and the light transmission.

In FIG. 12, the deflecting plates are arranged so as to be orthogonal to each other so that the transmission axes thereof are diagonal in the drawing. In such an arrangement, in each of the main liquid crystal alignment regions, the direction of inclination of the liquid crystal molecules 21 coincides with the direction that bisects the transmission axis of the polarizing plate on both sides, that is, the upper, lower, left, and right directions in FIG. Therefore, a good bright state can be displayed by applying the liquid crystal driving electric field E1, but a dark line 25 as shown in FIG. 12 is generated at the boundary between the liquid crystal alignment regions. The dark line 25 corresponds to a portion where the tilt direction of the liquid crystal molecules 21 coincides with the direction of the transmission axis of the deflection plate. Regarding the direction of the transmission axis of the deflecting plate, even if the liquid crystal is tilted in that direction, it does not transmit light, so the dark line 25 shown in FIG.
Will occur.

The dark line 25 as described above does not cause a serious problem on the display. For example, when the voltage is changed from a black display state in which no voltage is applied to a white display state by applying a voltage, the dark line 25 is temporarily not displayed. A change in the orientation, that is, a change in the orientation of the liquid crystal molecules 21 in a direction defined by the electric field from the control electrode 73 may be followed by a secondary orientation change in which the liquid crystal molecules 21 change the inclination direction. Can be a problem in some cases. In this case, the shape and width of the dark line 25 are changed after the dark line 25 is generated. The time scale of this secondary alignment change is slower than the temporary alignment change, and causes the light transmittance of the corresponding pixel to change over time. Changes in light transmittance over time can be roughly divided into two patterns. One is a case where the change from black to white is substantially delayed, which causes an afterimage. On the contrary, there is a case where the brightness once becomes bright and then gradually becomes dark. In this case, the brightness of the display in the steady state is insufficient.

As described above, when the generation of the dark line 25 becomes a problem, an optically anisotropic medium called a quarter-wave plate is inserted between the deflecting plate and the liquid crystal 20, and By forming the layer so that the circularly polarized light is incident, the generation of the dark line 25 can also be eliminated. In this example, since the control electrode 73 is formed of a transparent electrode, the elimination of the dark line 25 of the present invention directly leads to an improvement in element transmittance and response characteristics. As the quarter-wave plate, a stretched film of polycarbonate or the like can be used as a single layer or a laminate, and is preferably arranged on both sides of the liquid crystal layer so that the optical axes are orthogonal to each other. When a laminate of a plurality of stretched films called a broadband quarter-wave plate is used, the corresponding layers may be arranged on both sides of the liquid crystal layer so as to be orthogonal to each other.

Note that even in the case where a change in transmittance is observed in the normal driving method such that the image becomes brighter and then gradually becomes darker, a black image is formed for each frame of the display for the purpose of sharpening an image when displaying a moving image. When the driving for inserting the display is performed, such a temporal change does not pose a problem.

In this example, the operation of the liquid crystal 20 is performed in substantially the same manner as in the first embodiment. Here, particularly in the case of the homogeneous mode, the compensating film having negative refractive index anisotropy (the refractive index of the optical axis is small) is adjusted so that the optical axis coincides with the optical axis of the liquid crystal when no voltage is applied. When used in the arranged normally black mode, good viewing angle characteristics can be obtained. At this time, it is preferable that the retardation of the compensation film and the retardation of the liquid crystal layer have opposite signs and have the same absolute value. It is also possible to improve display contrast and viewing angle characteristics by using a biaxial compensation film.

The method of manufacturing the multi-domain liquid crystal display device of this embodiment can be carried out according to the method of the first embodiment described with reference to FIGS. That is, in FIG. 6B, the control electrode 73 may be formed instead of the pixel electrode 71, and in FIG. 7C, the pixel electrode 71 may be formed instead of the control electrode 73. . When patterning the pixel electrode 71, an opening 74 is also formed. The planar shape of each component of the multi-domain liquid crystal display device manufactured by the above manufacturing method is as shown in FIG. 6, and the size of the pixel is approximately 100 μm in width.
m × approximately 300 μm vertically. The planar shape of each component is not limited to the shape shown in FIG. 6, and various shapes can be considered as shown in FIG. 20 described later.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Third Embodiment FIG. 13 is a schematic partial sectional view (corresponding to FIG. 2 of the first embodiment) showing the configuration of a multi-domain liquid crystal display device according to a third embodiment of the present invention, and FIG. FIG. 3 is an equivalent circuit diagram of a pixel of the multi-domain liquid crystal display device. The configuration of the multi-domain liquid crystal display device of this example is significantly different from the configuration of the first embodiment described above in that the pixel electrodes are formed so as not to be completely floating. That is, the multi-domain liquid crystal display device of this example has the structure shown in FIG.
As shown in FIG. 14, in order to prevent charges from being accumulated in the pixel electrode 71 for some reason, a coupling capacitor 12 is provided between the pixel electrode 71 and the control electrode 73 as shown in FIG.
6, a coupling resistor 1 having a substantially finite resistance value
For example, a semiconductor film 62 of amorphous silicon or the like is formed in place of the interlayer insulating film 63 of the first embodiment so that 35 is connected. Then, a desired resistance value can be obtained by doping the semiconductor film 62 with appropriate impurity ions.

When a resistor is connected in parallel to the additional capacitance 127 in FIG. 14, the common capacitance line 72 and the pixel electrode 7
A finite coupling resistance may be connected by forming a semiconductor film 62 of amorphous silicon or the like in the same manner as described above, instead of the interlayer insulating film 63 between them. Coupling resistance 135
In order to prevent the display from burning due to the influence of the electric charge accumulated in the pixel electrode 71 and the occurrence of an afterimage exceeding the response time of the liquid crystal when displaying a moving image,
The value is set so that the accumulated charge is discharged. Depending on the usage of the liquid crystal display device, 1
The discharge can be completed within the frame display period, or can be completed by suspending the operation for several seconds to several minutes. Other than this, it is substantially the same as the first embodiment described above. Therefore, in FIG. 13 and FIG.
5 are denoted by the same reference numerals and description thereof will be omitted.

The method of manufacturing the multi-domain liquid crystal display device of this example can be carried out in accordance with the method of the first embodiment described with reference to FIGS. That is, in the process according to FIGS. 6B and 7C,
After an amorphous silicon film is formed on the entire surface by a CVD method, the semiconductor film 62 is simultaneously patterned into a desired shape when the amorphous silicon is patterned into a desired shape by photolithography to form the active layer 64. I just need.

FIG. 15 is an equivalent circuit showing a pixel of a modified example of the multi-domain liquid crystal display device of this example. In this modified example, as shown in the figure, a TFT 141 is formed so as to connect each pixel electrode 71 and a common capacitance line 72, and a TFT 141 is formed.
By connecting the gate of the FT 141 to the previous gate bus line 55, the potential of the common capacitance line 72 is changed to the pixel electrode 71 at the moment when the previous gate bus line 55 is selected.
, The electric charge accumulated in the pixel electrode 71 can be discharged.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Fourth Embodiment FIG. 16 is a schematic partial sectional view (corresponding to FIG. 2 of the first embodiment) showing the configuration of a multi-domain liquid crystal display device according to a fourth embodiment of the present invention. The configuration of the multi-domain liquid crystal display device of this example is significantly different from that of the first embodiment described above in that pixel electrodes and control electrodes are formed on color layers and light-shielding layers. That is, in the multi-domain liquid crystal display device of this example, as shown in FIG. 16, the color layer 91 and the light shielding layer 93 are formed on the first substrate 11, and the pixel electrode 71 and the control electrode 73 The pixel electrode 71 is opposed to the common capacitance line 72 via the capacitance terminal 75. Other than this, it is substantially the same as the first embodiment described above. Therefore, in FIG. 16, the same components as those in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof will be omitted.

The method of manufacturing the multi-domain liquid crystal display device of this embodiment can be carried out according to the method of the first embodiment described with reference to FIGS. That is, in a process according to FIGS. 6B and 7C, after forming the active layer 64, chromium is formed by sputtering on the entire surface, and then chromium is patterned into a desired shape by photolithography. Thus, the drain bus line 56, the drain terminal 58, and the source terminal 57 were formed, and at the same time, the capacitor terminal 75 was formed. In addition, T
The protective insulating film 65 of the FT 54 was formed, the light-shielding layer 93 was formed using a black resist, and the R, G, and B color layers 91 were formed using a color resist. Subsequently, an overcoat layer 92 was formed and planarized, and a pixel electrode 71, an interlayer insulating film 63, and a control electrode 73 were formed. The control electrode 73 is connected to the source terminal 57, and the pixel electrode 71 is connected to the capacitor terminal 75 through contact holes. The pixel electrode 73 is floating while being connected to the capacitor terminal 75.

By forming the semiconductor film 62 between the pixel electrode 71 and the control electrode 73, the pixel electrode 71 can be made not to be completely floating, as in the third embodiment.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Fifth Embodiment FIG. 17 is a schematic plan view showing a configuration of a pixel of a multi-domain liquid crystal display device according to a fifth embodiment of the present invention, and FIG.
19 is a schematic partial cross-sectional view taken along line FF ′ of FIG.
FIG. 18 is a schematic partial sectional view taken along line GG ′ of FIG. 17.
The configuration of the multi-domain liquid crystal display device of this example is significantly different from the configuration of the first embodiment described above in that a TFT as a switching element is formed in a top gate structure. That is, as shown in FIGS. 17 to 19, the multi-domain liquid crystal display device of this example has a TF
T54 is formed in a top gate structure in which the gate bus line 55 is located above the source terminal 57 and the drain terminal 58. Other than this, the first
This is substantially the same as the embodiment. Therefore, in FIG. 17 to FIG. 19, each part corresponding to the constituent part in FIG. 1 to FIG.

The method of manufacturing the multi-domain liquid crystal display device of this example can be carried out in accordance with the method of the first embodiment described with reference to FIGS. That is, in the process according to FIGS. 6A to 7C,
A drain bus line 56, a drain terminal 58, a source terminal 57, and a control electrode 73 are simultaneously formed by depositing and patterning chromium on the first substrate 11,
Subsequently, an amorphous silicon layer, an insulating layer, and a chromium sputtered film were formed, and these were collectively patterned to form a TFT 54. Furthermore, a pixel electrode 71 was formed by forming an interlayer insulating film 63 made of silicon nitride, followed by forming an ITO film by sputtering and patterning. The pixel electrode 71 was floating, and an opening 74 was provided in alignment with the position of the control electrode 73. Next, a gate insulating film 61 and a common capacitance line 72 were formed by continuously depositing silicon oxide and ITO by sputtering and patterning them together.

According to this example, only the structure of the TFT 54 is changed from the bottom gate structure to the top gate structure.
As shown in FIG. 19, substantially the same multi-domain as the second embodiment described with reference to FIG. 10 can be formed.

Also here, by forming the semiconductor film 62 instead of the interlayer insulating film 63 between the pixel electrode 71 and the control electrode 73 or the gate insulating film 61 between the pixel electrode 71 and the common capacitance line 72, As in the third embodiment, the pixel electrode 71 may not be completely floating.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Sixth Embodiment FIG. 20 is a diagram showing a planar shape of a combination example of a pixel electrode and a control electrode of a multi-domain liquid crystal display device according to a sixth embodiment of the present invention, and FIGS. The figure which shows the planar shape of a basic structure in the example of combination of the pixel electrode and the control electrode of the same multi-domain liquid crystal display device, FIG. 23 is an example which applied the same basic structure to the same multi-domain liquid crystal display device. It is a figure showing a plane shape. That is, the pixel electrode 71 and the control electrode 7 of the multi-domain liquid crystal display device of this example
Various examples of the combination example 3 can be considered as shown in FIGS. Here, FIG.
(N) and basic configuration examples of FIGS. 22 (o) to (r), FIG.
The planar shape of the application example of 3 (s) to (y) is the pixel electrode 71.
FIG. 3 is a diagram in which a control electrode 73 is projected onto a certain plane. In particular, the control electrode 73 is an opening 74 provided on the pixel electrode 71.
Only the part that can be seen from is drawn.

In this example, the positional relationship between the control electrode 73, the opening 74 provided on the pixel electrode 71, and the end of the pixel electrode 71 is important. In order to explain these positional relationships, what are the positional relationships in a plan view will be described. First, a basic combination example of the pixel electrode 71, the control electrode 73, and the end of the pixel electrode 71 using the unit electrodes shown in FIGS.
(R), and then an application example in which these unit electrodes are applied to an actual liquid crystal display device will be described with reference to FIGS.
This will be described with reference to (y). For the sake of explanation, the pixel electrode 71 and the control electrode 73 are described as if they are on the same plane.
3 are on different planes. Note that a configuration in which some or all of these electrodes 71 and 73 are on the same plane is also possible as long as conduction is ensured through contact holes and the like.

The unit electrode shown in FIG.
Is a rectangle, and the control electrode 7 extends along one side of the pixel electrode 71.
3 are disposed, and the remaining three sides of the pixel electrode 71 are openings or pixel electrode end portions 76. In the unit electrode shown in FIG. 21J, the pixel electrode 71 is square and the control electrodes 73 are arranged along two sides of the pixel electrode 71, and the remaining two sides of the pixel electrode 71 are formed as openings or pixel electrode ends. It is characterized by being a part 76. FIG.
The unit electrode of 1 (k) has a square pixel electrode 71 and control electrodes 73 arranged along three sides of the pixel electrode 71, and the remaining one side of the pixel electrode 71 has an opening or a pixel electrode end. 76. FIG.
In the unit electrode (1), the pixel electrode 71 is triangular, and the control electrodes 73 are arranged along two sides of the pixel electrode 71.
The remaining one side of the pixel electrode 71 is an opening or a pixel electrode end 76. In the unit electrode shown in FIG. 21 (m), the pixel electrode 71 is triangular
The control electrode 73 is disposed along one side of the pixel electrode 71, and the remaining two sides of the pixel electrode 71 are openings or pixel electrode end portions 76. In the unit electrode shown in FIG. 21 (n), the pixel electrode 71 is a pentagon and the control electrodes 73 are arranged along two sides of the pixel electrode 71, and the remaining three sides of the pixel electrode 71 are openings or pixel electrode ends. It is characterized by being a part 76.

Next, the unit electrode shown in FIGS. 21 (i) to 21 (n) is used as a pixel repeating unit: approximately 100 μm in width × 300 μm in height.
About the example applied to the multi-domain liquid crystal display device of
Description will be made with reference to application examples of FIGS. The application example of FIG. 23 (s) uses some of the unit electrodes of FIG. 21 (i). That is, the unit electrode (i) and the unit electrode whose unit electrode (i) is symmetrical with respect to the control electrode 73 are arranged so as to share the control electrode 73 with each other to form an electrode such as the electrode (o). Then, two electrodes (o) were used to form one pixel electrode of a multi-domain liquid crystal display device. The reason for using the electrode (o) is to control the direction of the liquid crystal in approximately two directions by the oblique electric field from the control electrode 73 and the oblique electric fields at the left and right ends of the electrode (o). This FIG.
In the application example of (s), the control electrode 73 is set to be parallel to the long side of the pixel. When applied to a multi-domain liquid crystal display device, the pixel electrode 71 does not have a structure in which the pixel electrode 71 is divided by the control electrode 73 as shown in the electrode (o), and the pixel electrode 71 on one pixel has the same potential. A joint is provided. FIG. 2 shows that the junction is provided so that the pixel electrode 71 on one pixel has the same potential.
In the application example of 3 (t), the unit electrode (l) is applied to the application example of FIG. 23 (u), and the unit electrode (j) is applied to the application example of FIG.
The unit electrode (k) and the unit electrode (n) are applied to the application example of FIG. 23 (x), and the unit electrode (i), the unit electrode (l) and the unit electrode (j) are applied to the application example of FIG. The same applies when applying.

In the application example of FIG. 23 (t), the electrode (o) is
These were arranged such that the control electrodes 73 were parallel to the short sides of the pixels, thereby forming one pixel electrode of the multi-domain liquid crystal display device. The application example of FIG. 23 (u) includes a unit electrode (l). First, four unit electrodes (l) are arranged so as to share the control electrode 73 with each other to form an electrode such as an electrode (p), and a multi-domain liquid crystal display device is formed by using two of the electrodes (p). Of one pixel electrode. The reason why the unit electrode (l) and the electrode (p) are used is that the unit electrode (l) is formed by three oblique electric fields of the oblique electric field from the two control electrodes 73 of the unit electrode (l) and the oblique electric field at the pixel end. The above orientation is controlled in substantially one direction, and the unit electrode (l) is further changed to the electrode (p).
This is to control the direction of the liquid crystal in approximately four directions by arranging them as shown in FIG.

FIG. 23 (v) shows an example of application of the unit electrode (l).
And a unit electrode (m). Four unit electrodes (m) were arranged so that the control electrode 73 was on the outside, and were shaped like an electrode (q). An electrode (q) was disposed between two electrodes (p) and used to form one pixel electrode of a multi-domain liquid crystal display device. However, in the application example of FIG. 23 (v), among the control electrodes 73 outside the electrode (q), the electrode (p) is used in order to obtain alignment consistency between the electrode (p) and the electrode (q). The part in contact with is removed. As described above, the pixel electrodes are basically formed by using the unit electrodes (i) to (n), but the shape of the unit electrode is partially changed in order to obtain alignment consistency as described above. It is also possible.

FIG. 23 (w) shows an application example of the unit electrode (j).
It is composed of The shape of the unit electrode (j) was made substantially square, and the four unit electrodes (j) were arranged so as to share the control electrode 73 with each other to obtain a shape like an electrode (r).
Three electrodes (r) were used as one pixel electrode of a multi-domain liquid crystal display device. The reason why the unit electrode (j) and the electrode (r) are used is that the electrode (r) is formed by the four oblique electric fields of the oblique electric field from the two control electrodes 73 of the unit electrode (j) and the oblique electric field at the two pixel ends. This is because the upper alignment is controlled in substantially one direction, and the unit electrodes (j) are arranged like the electrodes (r) to control the liquid crystal directions in substantially four directions. FIG.
In the application example of (w), the number of the electrodes (r) is set to 3. However, the present invention is not limited to this, and can be arbitrarily designed according to the pixel size and application.

The application example of FIG. 23 (x) is composed of two unit electrodes (k) and two unit electrodes (n). The square of the unit electrode (k) was trapezoidal. The control electrode 73 was placed on the upper base of the trapezoid, and the two unit electrodes (k) were arranged so as to share the upper base. The unit electrode (n) is disposed on the oblique side of the electrode formed in this manner so as to share the control electrode 73 with the unit electrode (k). In assembling, the upper bottom of the trapezoid, that is, a part of the control electrode 73 is hidden in order to obtain alignment consistency. As a result, an electrode is formed on the rectangular pixel electrode 71 which looks as if the “Y” -type and “Y” -type inverted control electrodes 73 are arranged. This was used as one pixel electrode of a multi-domain liquid crystal display device.

The application example of FIG. 23 (y) is formed of three types of unit electrodes, ie, a unit electrode (i), a unit electrode (l) and a unit electrode (j). In the application example of FIG. 23 (y), the unit electrode (i) is a trapezoid, the unit electrode (l) is a right-angled isosceles triangle where the angle sandwiched by the control electrodes 73 is a right angle, and the unit electrode (j) is The shape was a parallelogram. The oblique side of the unit electrode (l) is in contact with the upper bottom (opening) of the unit electrode (i), and the lower base of the unit electrode (i) is in contact with the unit electrode (j).
Share the control electrode 73. One pixel electrode of a multi-domain liquid crystal display device was formed by using several electrodes thus formed. Since a right-angled isosceles triangle is used for a part of the minute pixel electrode, the control electrode 73 and the opening 74 inside the pixel electrode 71 are approximately 4
The angle is 5 ° or approximately 135 °. FIG.
In any of the application examples (s) to (y), the pixel electrode is basically formed using the unit electrode. However, in order to obtain alignment consistency in the whole pixel, the unit electrode is formed. Can be partially changed. A multi-domain liquid crystal display device having a pixel electrode designed as described above was manufactured. The details of this control electrode can be implemented according to those of the second embodiment.

FIGS. 24 to 30 show microscopic photographs of the orientation states of the application examples shown in FIGS. 23 (s) to 23 (y). In FIGS. 24 to 27 and FIG. 29, the arrangement method of the two polarizing plates makes the absorption axes of the polarizing plates orthogonal to each other, and sets the absorption axis of one of the polarizing plates to the long side of the pixel. About 45 °
In the direction of 28 and FIG. 30, in the arrangement method of the two polarizing plates, the absorption axes of the polarizing plates are made orthogonal to each other, and the absorption axis of one of the polarizing plates is substantially 0 ° with respect to the long side of the pixel. The direction is set.

According to this example, in any of the application examples shown in FIGS. 23 (s) to (y), the periphery of the control electrode 73, the periphery of the opening 74, and the oblique direction from the periphery of the pixel electrode 71. Good multi-domain liquid crystal alignment was obtained by the effect of the electric field. In particular, in the pattern of the application example of FIG. 23 (w), the viewing angle characteristics were good, the transmittance was high, and the alignment excellent in stability was obtained. In the application example of FIG. 23 (w), since the shape of the unit electrode (j) is substantially square, the liquid crystal falls down in a diagonal direction. Therefore, the orientation direction is different by approximately 90 ° between the adjacent unit electrodes (j). On the electrode (r), it has a four-fold symmetrical orientation divided by the “+” type control electrode 73.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

{Seventh Embodiment} In a seventh embodiment of the present invention, FIG.
In the application example of (w), the influence on the alignment controllability when the control electrode voltage coefficient (control electrode voltage / pixel electrode voltage) was changed was compared and examined. Here, the pixel electrode voltage and the control electrode voltage indicate voltages of the pixel electrode 71 and the control electrode 73 with reference to the voltage of the common electrode 81. As described above, the voltage ratio between the pixel electrode voltage and the control electrode voltage is determined by the coupling capacitance 126 between the pixel electrode 71 and the control electrode 73,
Additional capacitance 1 between pixel electrode 71 and common capacitance line 72
27 and the liquid crystal capacity 125. Here, when the voltage of the common capacitance line 72 is the same voltage as that of the common electrode 81, (control electrode voltage coefficient) = ｛(capacity value of the liquid crystal capacitance 125) + (capacity value of the coupling capacitance 126) +
(The capacitance value of the additional capacitance 127) / (the capacitance value of the coupling capacitance 126).

Although the liquid crystal capacitance 125 fluctuates due to a change in the alignment state, for simplicity, the liquid crystal capacitance 125 was considered as the maximum value. That is, when calculating the capacitance value of the liquid crystal capacitor 125, the larger of the relative permittivity corresponding to the direction parallel to the liquid crystal molecular axis and the relative permittivity corresponding to the direction perpendicular to the liquid crystal molecular axis is used as the relative permittivity of the liquid crystal. Was used. In this example, the control electrode voltage coefficient was changed by changing the capacitance value of the coupling capacitor 126. Coupling capacity 1
26 is formed at the overlapping portion of the pixel electrode 71 and the control electrode 73, the capacitance value of the coupling capacitor 126 is determined by the area of the overlapping portion, the thickness of the interlayer film between the two electrodes 71 and 73, and the relative dielectric constant. As shown in Table 1 below, an example is shown in which the area of the overlapping portion between the control electrode 73 and the pixel electrode 71 is changed. The interlayer film between the electrodes 71 and 73 was made of silicon nitride having a thickness of about 200 nm by CVD. The relative permittivity of the silicon nitride film is approximately 6.4.

[0116]

[Table 1]

Next, as shown in Table 1, the TFT-LCD (Liquid Cry) having the control electrode voltage coefficient changed.
stal device) was manufactured and a display operation was performed, and observation was performed with a microscope and visually. Each value of the control electrode voltage coefficient of Table 1, 1.1, 1.2, 1.3, and 1.
Microscopic pictures of the pixels at the time of display corresponding to Nos. 4 and 4 are shown in FIG. 31, FIG. 32, FIG. 33 and FIG. FIG.
As is clear from FIGS. 1 to 34, in each of the TFT-LCDs having different control electrode voltage coefficients, the multi-domain liquid crystal alignment control based on the principle of the present invention could be realized. In particular, when the control electrode voltage coefficient was 1.2 or more, more preferably 1.3 or more, alignment control could be more accurately realized. In contrast, in a TFT-LCD having a control electrode voltage coefficient as small as 1.1,
A slight roughness was observed by visual observation. As is clear from the above results, regarding the control electrode voltage coefficient,
The larger the value is, the better the alignment controllability is, but the voltage applied to the pixel electrode is relatively reduced accordingly, so that the control electrode voltage coefficient becomes too large in terms of driving voltage or brightness. Is not desirable. Considering these facts, it is considered that the control electrode voltage coefficient is most preferably about 1.3.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Eighth Embodiment In an eighth embodiment of the present invention, FIG.
Based on the application example of (w), experimental liquid crystal cells having different airflows with different sizes of the micro-alignment regions were manufactured, and each was compared and examined. Here, the micro-alignment region refers to the control electrode 73, the end of the pixel electrode 71, and the opening 7 provided in the pixel electrode 71.
4 shows a region divided by a boundary such as 4 and shows a region where the liquid crystal takes a substantially single orientation. In the application example of FIG. 23 (w) in this example, the size of one micro-alignment region is approximately 40 μm square. Based on this, an experimental liquid crystal cell having a micro alignment region size of about 20 μm square was manufactured. As a comparative example, the size of the micro-alignment region was approximately 40 μm.
An experimental liquid crystal cell having an m square was also manufactured. In these experimental liquid crystal cells, the TFT, the gate bus line, the drain bus line, and the like are omitted, and the structure is such that a voltage can be directly applied to each of the control electrode 73 and the pixel electrode 72.

FIG. 35 is a photomicrograph of the experimental liquid crystal cell of this example after switching the voltage from a dark state to a bright state. FIG. 35 (a) is a photograph showing a state after the voltage is switched from the dark state to the bright state and left for 20 ms, and FIG. 35 (b) is a state after the voltage is switched from the dark state to the bright state and left for 1 second or longer. It is a photograph which shows a situation. As is clear from comparison of the two photographs, in this example, an alignment state substantially equal to the steady state alignment state was obtained within 20 ms after voltage application, and the alignment stability and the electro-optical response characteristics were excellent. I understand. Specific measurement values of the response time were about 15 ms from dark to light, and about 9 ms from light to dark.

On the other hand, FIG. 36 shows a micrograph of the comparative example after switching the voltage from the dark state to the bright state. FIG. 36A is a photograph showing a state after the voltage is switched from a dark state to a bright state and left for 20 ms.
(B) is a photograph showing a state after the voltage is switched from a dark state to a bright state and left for one second or longer. As is clear from the comparison between the two photographs, in the comparative example, it was found that it takes a little time to obtain a bright steady state alignment state after voltage application. The specific measurement value of the response time is dark →
The light was about 140 ms, and the light → dark was about 9 ms.

As described above, in this example, regarding the electro-optical response characteristics, the size of the micro-alignment region is reduced (20
(μm square) increases the size of the micro-alignment region (4
(0 μm square). However, regarding the light transmittance of the entire device, it was found that it is preferable that the size of the orientation region of the minute region is larger due to the difference in the density of dark lines observed at the boundaries of the minute regions. That is, the size of the micro-alignment region is increased (40 μm).
m square), the size of the micro-alignment region becomes smaller (2
It was confirmed that the light transmittance of the entire experimental liquid crystal cell was higher than that in the case of (0 μm square).

For the above reasons, the size of the micro-alignment region can be appropriately selected depending on the use such as whether or not to display a moving image and in consideration of the desired pixel pitch of the TFT-LCD. In the case of displaying a moving image, it is preferable that the width is approximately 20 μm square or less, and in the case of not displaying a moving image, the width is approximately 40 μm square or more. Of course, it may be set in the range of 20 μm to 40 μm depending on the application.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Ninth Embodiment FIG. 37 is a schematic plan view showing a configuration of a pixel of a multi-domain liquid crystal display device according to a ninth embodiment of the present invention, and FIG.
39 is a schematic partial cross-sectional view taken along the line HH ′ in FIG. 37, and FIG.
38 is a schematic partial cross-sectional view taken along the line II ′ of FIG. 37.
The configuration of the multi-domain liquid crystal display device of this example is significantly different from the configuration of the first embodiment described above in that the control electrode is formed integrally with the source terminal of the TFT as a switching element. That is, in the multi-domain liquid crystal display device of this example, as shown in FIGS. 37 to 39, the control electrode 73 is formed integrally with the source terminal 57 of the TFT 54 from an opaque metal such as chrome.
With this configuration, as described above, the coupling capacitance 1
When the capacitance value of the capacitor 26 is large, there is a concern that the aperture ratio may be reduced. In this example, a sufficient aperture ratio is ensured in consideration of this point.
Specifically, a coupling capacitor electrode 171 is formed below the control electrode 73 with the gate insulating film 61 interposed therebetween, and the coupling capacitor electrode 171 and a pixel formed above the control electrode 73 with the interlayer insulating film 63 interposed therebetween. Each of the electrodes 71 has an overlapping portion with the control electrode 73, and is connected to each other through a contact hole 172. In FIG. 37, most of the coupling capacitance electrode 171 is hidden under the control electrode 73, which is difficult to understand. However, as is clear from FIG. 39, the coupling capacitance electrode 171 substantially follows the shape of the control electrode 73. It is located on the lower side.

According to this example, the coupling capacitors 126 can be formed on the upper and lower sides of the control electrode 73. Therefore, even when the capacitance value of the coupling capacitor 126 is increased, the area of the control electrode 73 can be sufficiently increased without increasing the area. A high aperture ratio can be secured. In this example, the example in which the control electrode 73 is formed in a lower layer than the pixel electrode 71 is shown. However, the pixel electrode 71 can be formed in a lower layer of the control electrode 73.
By connecting the coupling capacitor electrode 171 disposed in the lower layer of the pixel electrode 171 and the control electrode 73 in the upper layer through the contact hole 172, coupling capacitance can be formed on both the upper and lower sides of the pixel electrode 71.

Further, according to this example, the additional capacity 127
As for, a configuration for obtaining a sufficient capacitance value with a small overlapping area is adopted. That is, in the contact hole 177, the additional capacitance terminal 175 connected to the common capacitance line 72 by the connection terminal 176, and the pixel electrode 71
The additional capacitance 127 is formed by a superimposed portion of the above. Here, the common capacitance line 72 is formed of a metal film of the same layer as the gate bus line 55, and the additional capacitance terminal 175 is formed of a metal film of the same layer as the drain bus line 56. As described above, since the additional capacitance terminal 175 is formed in a layer closer to the pixel electrode 71 than the common capacitance line 72, a sufficient capacitance value of the additional capacitance 127 can be secured with a small overlapping area.

In this example, the example in which the additional capacitance 127 is formed via the interlayer insulating film 63 has been described.
However, even when the additional capacitance 127 is formed via the second insulating film 63 and 61, a larger capacitance value can be easily secured than when the additional capacitance 127 is formed via the two insulating films 63 and 61. In addition, in order to obtain a sufficient capacitance value with a small overlapping area and secure an aperture ratio, in addition to the above-described contrivance in the layer structure, for example, the thickness of the gate insulating film 61 or the interlayer insulating film 63 is reduced. Also, it is effective to increase the dielectric constant.

Further, in addition to the above-mentioned effect on ensuring the aperture ratio, in this example, by forming the control electrode 73 with a metal film, there is also an effect that the patterning accuracy of the control electrode 73 can be improved. The reason for this is usually
This is because the opaque metal such as Cr has higher wet etching accuracy than the transparent electrode such as ITO. In the multi-domain liquid crystal display device of the present invention, since the capacitance value of each capacitor formed in the overlapping portion of each electrode is an important design parameter, it is important to improve the patterning accuracy of each electrode that determines the area of the overlapping portion. It is.

Next, a method of manufacturing the multi-domain liquid crystal display device of this example will be described in the order of steps with reference to FIGS. First, as shown in FIG. 41A, chromium is sputter-deposited on a first substrate 11 made of glass, and then chromium is patterned by wet etching using a photolithography technique to form a gate bus line 55, Common capacitance line 72 and coupling capacitance electrode 17
1 was formed. Subsequently, as shown in FIG.
A gate insulating film 61 was formed uniformly by depositing silicon nitride using a VD method. Note that the gate insulating film 61 may be, for example, silicon dioxide or the like, or may be a stacked film of silicon nitride and silicon oxide. Of course, an organic film or the like may be used. Next, an amorphous silicon layer is formed by a CVD method, and is patterned by dry etching using a photolithography technique.
An active layer 64 of the FT 54 was formed.

Next, as shown in FIG. 42 (c), after chromium is formed by sputtering, patterning is performed by wet etching using a photographic technique to form a drain bus line 56, a drain terminal 58, a source terminal 57, The control electrode 73 and the additional capacitance terminal 175 were formed. continue,
As shown in FIG. 42D, a silicon nitride film is formed by CVD to form an interlayer insulating film 63 integrally and uniformly, and further, the interlayer insulating film 63 and the gate insulating film are dry-etched using a photolithography technique. 61 was continuously patterned to form contact holes 172 and 177. Subsequently, as shown in FIG. 43, ITO was formed by sputtering and patterned by wet etching using a photolithography technique to form a floating pixel electrode 71 and a connection terminal 176. Note that, in the step of forming the pixel electrode 71 and the connection terminal 176,
By patterning O by dry etching instead of wet etching, patterning accuracy can be improved.

As described above, the first substrate 11 is formed by the 5PR process using the photolithography technique a total of five times.
To form Although not described in detail, in the multi-domain liquid crystal display device of the present invention, all peripheral elements such as a gate bus line terminal, a drain bus line terminal, a common capacitance line connection, and an electrostatic protection transistor are provided around the display area. Can be formed simultaneously in parallel with the above steps without any additional process. For details, see, for example,
No. 2409, for example. Other processes such as a manufacturing process of the second substrate 12 and a bonding process of the first substrate 11 and the second substrate 12 can be performed according to the manufacturing method of the first embodiment. .

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Tenth Embodiment FIG. 44 is a schematic plan view showing the configuration of a pixel of a multi-domain liquid crystal display device according to a tenth embodiment of the present invention.
5 is a schematic partial cross-sectional view taken along the line KK ′ of FIG.
FIG. 6 is a schematic partial sectional view taken along line LL ′ of FIG. The configuration of the multi-domain liquid crystal display device of this example is greatly different from the configuration of the first embodiment described above in that a discharge TFT is arranged on a gate bus line corresponding to a stage preceding a pixel of interest. It is. That is, the multi-domain liquid crystal display device of this example has the structure shown in FIGS.
As shown in FIG. 15, a discharge TFT 141 is disposed on a gate bus line 55 corresponding to the preceding stage of a pixel of interest, particularly in the modification of the third embodiment described with reference to FIG. Here, the gate terminal, the drain terminal, the source terminal, the active layer, and the like constituting the TFT 141 can be formed in parallel with the display TFT 54. T
The drain terminal of the FT141 is the contact hole 1
And a source terminal connected to the pixel electrode 7 through the contact hole 143.
1 connected. With this configuration, the common capacitance line 72 is set at the moment when the gate bus line 55 in the previous stage is selected.
By writing the potential of the pixel electrode 71 on the pixel electrode 71, the electric charge accumulated in the pixel electrode 71 can be discharged.

In this example, in the opening 74 provided in the pixel electrode 71, a portion corresponding to the opening 74 to which the control electric field from the control electrode 73 disposed below acts on the interlayer insulating film. 63 is removed. With such a configuration, there is no voltage loss in the insulating film portion between the control electrode 73 and the liquid crystal layer, and an effect that the electric field from the control electrode 73 is directly applied to the liquid crystal layer can be obtained. Further, since the concave shape formed by removing the interlayer insulating film 63 matches the tilt direction of the liquid crystal molecules due to the action of the gradient electric field, the effect of stabilizing the liquid crystal alignment at the boundary of the fine alignment region is obtained. . Since the removal of the interlayer insulating film 63 can be performed simultaneously with the step of exposing the terminal portion around the display area,
In particular, no additional steps are required.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and there may be changes in the design without departing from the gist of the present invention. Is also included in the present invention. For example, an example in which a TFT is used as an element that operates as a switching element has been described.
A diode such as an nsulator metal element may be used. Also, although the example has been described in which ITO is used as the transparent electrode forming the pixel electrode and the control electrode,
However, other materials such as a Nesa film (tin oxide film) can be used. When the control electrode is made of a transparent electrode, the transparent electrode may be used only for a part of the control electrode. In addition, although an example has been described in which chromium is used as the metal constituting the gate bus line, the source terminal, the drain terminal, and the like, other materials such as molybdenum, tantalum, or an alloy thereof may be used. It is.

[0138]

As described above, according to the present invention, since the control electrode provided for each pixel is driven by the switching element provided for each pixel, the pixel is displayed brightly and darkly. Alternatively, even in the case of an intermediate display, the control electrode potential is controlled accordingly, so that the domain formation of the liquid crystal can be reliably controlled by the oblique electric field generated so as to spread from the control electrode. Further, a divided voltage of the control electrode voltage is applied to the pixel electrode via the coupling capacitor, so that
The control electrode and the pixel electrode are composed of two switching elements only.
One electrode potential can be controlled. Therefore, the number of complicated steps such as the fine processing step of the common electrode is increased,
A multi-domain liquid crystal display device having high contrast and excellent viewing angle characteristics can be provided without requiring an advanced bonding technique.

[Brief description of the drawings]

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

FIG. 2 is a schematic partial cross-sectional view taken along line AA ′ of FIG.

FIG. 3 is a schematic partial cross-sectional view taken along line BB ′ of FIG. 1;

FIG. 4 is a schematic partial cross-sectional view taken along the line CC ′ of FIG. 1;

FIG. 5 is an equivalent circuit diagram of a pixel of the multi-domain liquid crystal display device.

FIG. 6 is a process chart showing a method for manufacturing the multi-domain liquid crystal display device in the order of steps.

FIG. 7 is a process chart showing a method of manufacturing the multi-domain liquid crystal display device in the order of steps.

FIG. 8 is a schematic plan view showing a configuration of a pixel of a multi-domain liquid crystal display device according to a second embodiment of the present invention.

FIG. 9 is a schematic partial cross-sectional view taken along the line DD ′ of FIG. 8;

FIG. 10 is a schematic partial sectional view taken along line EE ′ of FIG. 8;

FIG. 11 is a diagram schematically showing a multi-domain liquid crystal alignment in the multi-domain liquid crystal display device.

FIG. 12 is a view schematically showing a state of transmitted light corresponding to a multi-domain alignment state in the multi-domain liquid crystal display device.

FIG. 13 is a schematic partial sectional view showing a configuration of a multi-domain liquid crystal display device according to a third embodiment of the present invention.

FIG. 14 is an equivalent circuit diagram of a pixel of the multi-domain liquid crystal display device.

FIG. 15 is an equivalent circuit diagram of a pixel in a modification of the multi-domain liquid crystal display device.

FIG. 16 is a schematic partial sectional view showing a configuration of a multi-domain liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 17 is a schematic plan view showing a configuration of a pixel of a multi-domain liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 18 is a schematic partial cross-sectional view taken along line FF ′ of FIG. 17;

19 is a schematic partial cross-sectional view taken along line GG ′ of FIG.

FIG. 20 is a diagram showing a planar shape of a combination example of a pixel electrode and a control electrode of a multi-domain liquid crystal display device according to a sixth embodiment of the present invention.

FIG. 21 is a diagram showing a planar shape of a basic configuration in an example of a combination of a pixel electrode and a control electrode of the multi-domain liquid crystal display device.

FIG. 22 is a diagram showing a planar shape of a basic configuration in an example of a combination of a pixel electrode and a control electrode of the multi-domain liquid crystal display device.

FIG. 23 is a diagram illustrating a planar shape of an example in which the basic configuration is applied to the multi-domain liquid crystal display device.

FIG. 24 is a micrograph showing an alignment state of pixels of the multi-domain liquid crystal display device.

FIG. 25 is a micrograph showing an alignment state of pixels of the multi-domain liquid crystal display device.

FIG. 26 is a micrograph showing an alignment state of pixels of the multi-domain liquid crystal display device.

FIG. 27 is a micrograph showing an alignment state of pixels of the multi-domain liquid crystal display device.

FIG. 28 is a micrograph showing an alignment state of pixels of the multi-domain liquid crystal display device.

FIG. 29 is a micrograph showing an alignment state of pixels of the multi-domain liquid crystal display device.

FIG. 30 is a micrograph showing an alignment state of pixels of the multi-domain liquid crystal display device.

FIG. 31 is a micrograph of a pixel during display of a multi-domain liquid crystal display device according to a seventh embodiment of the present invention.

FIG. 32 is a micrograph of a pixel during display of the multi-domain liquid crystal display device.

FIG. 33 is a micrograph of a pixel during display of the multi-domain liquid crystal display device.

FIG. 34 is a micrograph of a pixel during display of the multi-domain liquid crystal display device.

FIG. 35 is a photomicrograph of the experimental liquid crystal cell of the multi-domain liquid crystal display device according to the eighth embodiment of the present invention after switching the voltage from the dark state to the bright state.

FIG. 36 is a micrograph of a liquid crystal cell for comparison of the same multi-domain liquid crystal display device after a voltage is switched from a dark state to a bright state.

FIG. 37 is a schematic plan view showing a configuration of a pixel of a multi-domain liquid crystal display device according to a ninth embodiment of the present invention.

FIG. 38 is a schematic partial cross-sectional view taken along line HH ′ of FIG. 37.

39 is a schematic partial cross-sectional view taken along the line II ′ of FIG. 37.

40 is a schematic partial cross-sectional view taken along the line JJ ′ of FIG. 37.

FIG. 41 is a process view showing the method of manufacturing the multi-domain liquid crystal display device in the order of steps;

FIG. 42 is a process view showing the method of manufacturing the multi-domain liquid crystal display device in the order of steps;

FIG. 43 is a process view showing the method of manufacturing the multi-domain liquid crystal display device in the order of steps;

FIG. 44 is a schematic plan view showing a configuration of a pixel of a multi-domain liquid crystal display device according to a tenth embodiment of the present invention.

FIG. 45 is a schematic partial cross-sectional view taken along the line KK ′ of FIG. 44.

46 is a schematic partial cross-sectional view taken along line LL ′ of FIG. 45.

FIG. 47 is a schematic partial cross-sectional view showing a configuration of a pixel of a conventional multi-domain liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 1st board | substrate 12 2nd board | substrate 20 liquid crystal 21 liquid crystal molecule 54 TFT (switching element) 55 gate bus line 56 drain bus line 57 source terminal 58 drain terminal 59, 142, 143, 149, 172, 177
Contact hole 61 Gate insulating film 62 Semiconductor film 63 Interlayer insulating film 64 Active layer (semiconductor layer) 65 TFT protective film 71 Pixel electrode 72 Common capacitance line 73 Control electrode 74 Opening 75 Capacity terminal 76 Opening or pixel electrode end 81 Common electrode 91 Color layer 92 Overcoat layer 93 Light shielding layer 125 Liquid crystal capacitance 126 Coupling capacitance 127 Additional capacitance 135 Coupling resistance 141 TFT (discharge element) 171 Coupling capacitance electrode 175 Additional capacitance terminal 176 Connection terminal E1 Liquid crystal driving electric field

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigeyoshi Suzuki 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Hiroshi Hayama 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Hiroshi Kano 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Naoyasu Ikeda 5-7-1 Shiba, Minato-ku, Tokyo Japan Inside Electric Company (72) Inventor Kenichi Takatori 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation Inside (72) Inventor Takashi Nose 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation F-term in the formula company (reference) 2H090 KA05 LA01 LA03 LA08 MA01 MA02 MA09 MA14 2H091 FA11Y GA02 GA06 GA09 GA13 LA12 LA17 LA19 2H092 GA13 JA25 JA26 JA46 JB05 JB61 KA05 MA05 MA07 MA13 MA18 NA01 NA29 PA02 PA04 PA10

Claims (43)

[Claims] A liquid crystal sandwiched between a pair of substrates, a plurality of gate bus lines formed on one side of the substrates and extending in a horizontal direction, and a plurality of drain bus lines extending in a vertical direction; A plurality of pixels are arranged in a matrix corresponding to each of the intersections of the gate bus line and the drain bus line, and each of the pixels has a switching element, a pixel electrode, and an oblique direction with respect to the liquid crystal. A multi-domain liquid crystal display device comprising: a control electrode for generating an electric field to form a plurality of alignment regions in one pixel, wherein the control electrode is connected to one terminal of the switching element, The electrode has a coupling capacitance between the electrode and the control electrode, and the control electrode is connected to the control electrode via the corresponding switching element when the corresponding gate bus line is selected. Is the drain signal voltage is applied from the bus line, multi-domain liquid crystal display device in the pixel electrode, characterized in that the partial pressure of the signal voltage through the coupling capacitor is applied. 2. The multi-domain liquid crystal display device according to claim 1, wherein the pixel electrode and the control electrode are configured so that the pixel electrode is a lower layer via an insulating film. 3. The multi-domain liquid crystal display device according to claim 1, wherein an opening is formed in said pixel electrode. 4. The multi-domain liquid crystal display device according to claim 3, wherein the control electrode applies an electric field from the opening to control an alignment state of the liquid crystal. 5. The multi-domain liquid crystal display device according to claim 1, further comprising a common capacitance line for adding a capacitance to the pixel electrode. 6. The multi-domain liquid crystal display device according to claim 5, wherein said common capacitance line is arranged at a position corresponding to said opening. 7. The multi-domain liquid crystal display device according to claim 5, wherein an additional capacitance of a predetermined capacitance is provided between the pixel electrode and the common capacitance line. 8. The multi-domain liquid crystal display device according to claim 1, wherein at least a part of said control electrode comprises a transparent electrode. 9. The control electrode has quarter-wave plates on both sides of a liquid crystal layer, and the quarter-wave plates are arranged so that their optical axes are orthogonal to each other. The multi-domain liquid crystal display device according to claim 8, wherein: 10. The liquid crystal device according to claim 1, further comprising a quarter-wave plate on both sides of the liquid crystal, wherein the optical axes of the quarter-wave plates are arranged to be orthogonal to each other. 1
The multi-domain liquid crystal display device according to the above. 11. The switching device according to claim 1, wherein the switching element is a TFT having a bottom gate structure.
The multi-domain liquid crystal display device according to any one of the above. 12. The switching device according to claim 1, wherein the switching element is a TFT having a top gate structure.
The multi-domain liquid crystal display device according to any one of the above. 13. The multi-domain liquid crystal display device according to claim 11, wherein the insulating film is formed integrally with an insulating film for protecting the TFT. 14. The device according to claim 1, wherein the control electrode is formed integrally with a source terminal of the TFT.
14. The multi-domain liquid crystal display device according to 2 or 13. 15. The multi-domain liquid crystal display device according to claim 3, wherein said opening is formed in a window shape. 16. The multi-domain liquid crystal display device according to claim 3, wherein said opening is formed so as to cut out from one side or both sides of said pixel electrode. 17. The multi-domain liquid crystal display according to claim 1, further comprising a resistance element between said pixel electrode and said control electrode for discharging electric charges accumulated in said pixel electrode. apparatus. 18. The multi-domain liquid crystal display device according to claim 17, wherein said resistance element has a substantially finite resistance value. 19. The multi-domain liquid crystal display device according to claim 5, further comprising a resistance element having a substantially finite resistance value between said pixel electrode and said common capacitance line. 20. The multi-domain liquid crystal display device according to claim 1, wherein the operation mode of the liquid crystal is a TN mode in which liquid crystal having a positive dielectric anisotropy is twisted. 21. The multi-domain liquid crystal display device according to claim 20, wherein the liquid crystal is spontaneous chiral. 22. The multi-domain liquid crystal display device according to claim 20, wherein the liquid crystal is non-spontaneous chiral. 23. The multi-domain liquid crystal display device according to claim 1, wherein the operation mode of the liquid crystal is a homogeneous mode in which liquid crystal having a positive dielectric anisotropy is uniformly aligned. 24. The multi-domain liquid crystal display device according to claim 1, wherein the operation mode of the liquid crystal is a VA mode in which liquid crystal having negative dielectric anisotropy is homeotropically (vertically) aligned. 25. The pixel electrode is formed of a plurality of small pixel electrodes having a rectangular shape, a control electrode is arranged along one side of the rectangular shape, and the remaining three sides have an opening or a pixel electrode end. Claim 1, characterized in that:
4. The multi-domain liquid crystal display device according to 2 or 3. 26. The pixel electrode is formed of a plurality of small pixel electrodes each having a quadrangular shape, control electrodes are arranged along two sides of the quadrangular shape, and the remaining two sides have an opening or a pixel electrode end. Claim 1, characterized in that:
4. The multi-domain liquid crystal display device according to 2 or 3. 27. The multi-domain liquid crystal display device according to claim 25, wherein the quadrangular shape is substantially a square. 28. The pixel electrode is formed of a plurality of triangular minute pixel electrodes, a control electrode is arranged along two sides of the triangle, and the other side is an opening or a pixel electrode end. 4. The multi-domain liquid crystal display device according to claim 1, wherein the multi-domain liquid crystal display device has an opening. 29. The pixel electrode is formed of a plurality of triangular small pixel electrodes, a control electrode is arranged along one side of the triangle, and the remaining two sides are openings or pixel electrode ends. 4. The multi-domain liquid crystal display device according to claim 1, wherein the multi-domain liquid crystal display device has an opening. 30. The pixel electrode is formed of a plurality of pentagonal minute pixel electrodes, control electrodes are arranged along two sides of the pentagon, and the remaining three sides are openings or pixel electrode ends. 4. The multi-domain liquid crystal display device according to claim 1, wherein the multi-domain liquid crystal display device has an opening. 31. The pixel electrode according to claim 25, wherein the pixel electrode is formed of a plurality of minute pixel electrodes.
0, wherein two or more kinds of micro pixel electrodes described in any one of 0 are combined.
4. The multi-domain liquid crystal display device according to 2 or 3. 32. A ratio of a control electrode voltage applied to the control electrode to a pixel electrode voltage applied to the pixel electrode based on a voltage of a common electrode is set to 1.1 to 1.4. 28. The multi-domain liquid crystal display device according to claim 27, wherein: 33. The multi-domain liquid crystal display device according to claim 32, wherein a ratio of the control electrode voltage to the pixel electrode voltage is set to 1.2 to 1.4. 34. The multi-domain liquid crystal display device according to claim 33, wherein a ratio of the control electrode voltage to the pixel electrode voltage is set to about 1.3. 35. The liquid crystal display device according to claim 27, wherein the size of the micro-alignment region in which the liquid crystal has a substantially single alignment is about 20 μm square or less. 36. The liquid crystal display device according to claim 27, wherein the size of the micro-alignment region in which the liquid crystal has a substantially single alignment is about 40 μm square or more. 37. The liquid crystal display device according to claim 27, wherein the size of the micro-alignment region in which the liquid crystal has a substantially single alignment is 20 to 40 μm square. 38. A coupling capacitance terminal electrically connected to one of the pixel electrode and the control electrode and one of the other electrodes not connected to the coupling capacitance terminal via a gate insulating film. 13. The multi-domain liquid crystal display device according to claim 11, wherein at least a part of the coupling capacitance is formed by performing the operation. 39. an additional capacitance terminal electrically connected to one of the pixel electrode and the common capacitance line;
8. The storage device according to claim 7, wherein at least a part of the additional capacitance is formed by superimposing, via a protective insulating film, one of the additional capacitance terminals to which the additional capacitance terminal is not connected.
The multi-domain liquid crystal display device according to the above. 40. an additional capacitance terminal electrically connected to one of the pixel electrode and the common capacitance line;
8. The multi-domain liquid crystal display device according to claim 7, wherein at least a part of the additional capacitance is constituted by overlapping with one of the other terminals to which the additional capacitance terminal is not connected via a gate insulating film. 41. A discharge element for discharging electric charges accumulated in the pixel electrode is disposed on a gate bus line corresponding to a stage preceding an arbitrary pixel.
The multi-domain liquid crystal display device according to the above. 42. A protection insulating film at a portion corresponding to an opening on which a control electric field from a control electrode disposed in a lower layer of the opening provided in the pixel electrode acts. Item 42. The multi-domain liquid crystal display device according to item 41. 43. A liquid crystal sandwiched between a pair of substrates, and a plurality of pixels arranged in a matrix on one side of the substrates, each of which includes a switching element, a pixel electrode, A multi-domain liquid crystal display device comprising: a control electrode for generating an oblique electric field with respect to the liquid crystal to form a plurality of alignment regions in one pixel, wherein the control electrode is one of the switching elements. Connected to a terminal, the pixel electrode has a coupling capacitance with the control electrode, a signal voltage is applied to the control electrode via the corresponding switching element, and the coupling voltage is applied to the pixel electrode. A multi-domain liquid crystal display device, wherein the divided voltage of the signal voltage is applied via a capacitor.