JP2000305097A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent decrease in the transmittance for light or decrease in the contrast by controlling the intensity of an electric field in the border between regions having different directions of electric fields to be almost same as the intensity of the electric field in both regions. SOLUTION: The running directions of electrodes are varied with a virtual line α as the border so that the directions of electric fields generated between a pixel electrode 5 and a counter electrode 4A are different from each other. The side line of the pixel electrode 5 in the bent part nearer to the counter electrode 4A forms an angle θ5, and this part is formed into an arch around the bent point 0 as the center of the counter electrode 4A nearer to the pixel electrode 5. By forming the structure, the whole electric field generating region EA between the pixel electrode 5 and the counter electrode 4A where light can be transmitted has a same width (the shortest distance 1 between the electrodes and it corresponds to the direction of the electric field) along the longitudinal direction. Therefore, the intensity of the electric field in the electric field generating region in the aforementioned bent part is controlled to be almost equal to the intensity of the electric field in the electric field generating region in other part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, for example, to a liquid crystal display device called a horizontal electric field type.

[0002]

2. Description of the Related Art An in-plane switching mode liquid crystal display device comprises a pair of transparent substrates disposed opposite to each other with a liquid crystal interposed therebetween in a pixel region on the liquid crystal side of one of the transparent substrates. Electrodes are formed, and an electric field generated between the electrodes controls the light transmittance of the liquid crystal with respect to light transmitted between the electrodes. In recent years, it has been known to form a region in which the direction of an electric field generated between the pair of electrodes is changed by bending the pair of electrodes (Japanese Patent Laid-Open No. 10-148826). ). Such a configuration is referred to as a so-called multi-domain system, which eliminates the inconvenience due to the viewing angle dependence of the liquid crystal display panel, which causes a luminance reversal phenomenon when the viewpoint is inclined obliquely to the main viewing angle direction of the liquid crystal display panel. It has become.

[0003]

However, in the liquid crystal display device having such a structure, when white display is performed using so-called normally black liquid crystal, the bent portion of the pair of electrodes becomes dark. In addition, it was confirmed that when darkening was performed using so-called normally white, the bent portion became bright. The former phenomenon leads to a decrease in light transmittance, and the latter phenomenon leads to a decrease in contrast. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal display device that does not cause a decrease in light transmittance or a decrease in contrast.

[0004]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, an electric field generating region for generating an electric field parallel to the substrate is provided, and this electric field generating region has regions where the directions of the electric fields are different from each other,
The electric field strength at the boundary between these areas is substantially the same as the electric field strength in each of the above areas. The liquid crystal display device thus configured is
Even if the electric field generating region extends so as to have a bent portion, an electric field having substantially the same intensity is generated in all the portions. Therefore, when white display is performed using so-called normally black as the liquid crystal, a decrease in light transmittance does not occur, and when darkness is performed using so-called normally white, a decrease in contrast is caused. Will not be.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the liquid crystal display device according to the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 is a plan view showing one of the pixels of a liquid crystal display device called a so-called in-plane switching method. Each pixel is arranged in a matrix to form a display unit. For this reason, the configuration of the pixel shown in FIG. 1 is the same as the configuration of the adjacent pixels on the left, right, up, and down.
First, a scanning signal line (gate line) 2 extending in the x direction in the drawing is formed of, for example, a chromium layer on a liquid crystal side surface of one of the transparent substrates 1 opposed to each other via a liquid crystal. I have. The gate line 2 is formed, for example, below the pixel region, as shown in the drawing, so that the region that substantially functions as a pixel is made as large as possible. The gate line 2 is supplied with a gate signal from outside the display unit.
T is driven. In addition, a counter voltage signal line 4 extending in the x direction in the figure is formed substantially at the center of the pixel region, for example, by the same material as the gate line 2. A plurality of counter electrodes 4A are integrally formed on the counter voltage signal line 4, and these counter electrodes 4A
And three, for example, are arranged side by side in the x direction in the figure. In this case, the counter voltage signal line 4 is positioned at the center of each counter electrode 4A. The counter electrode 4A is configured such that a signal serving as a reference for a video signal supplied to the pixel electrode 5 described later is supplied through the counter voltage signal line 4, and is connected to the pixel electrode 5. Then, an electric field having an intensity corresponding to the video signal is generated. This electric field has a component parallel to the surface of the transparent substrate 1, and the electric field composed of this component controls the light transmittance of the liquid crystal. This is the reason why the liquid crystal display device described in this embodiment is called a so-called horizontal electric field method.

The reference signal is supplied to the counter voltage signal line 4 from outside the display unit. Then, on the surface of the transparent substrate 1 on which the gate lines 2 and the counter voltage signal lines 4 are formed, an insulating film made of, for example, a silicon nitride film including the gate lines 2 and the counter voltage signal lines 4 (shown in FIG. Are formed. This insulating film functions as a gate insulating film in a region where a later-described thin film transistor TFT is formed, and an interlayer insulating film for the gate line 2 and the counter voltage signal line 4 in a region where a video signal line (drain line) 3 described later is formed. Function, a capacitive element Cadd described later
Has a function as a dielectric film in the formation region. In such an insulating film, a thin film transistor TFT is formed so as to overlap with the gate line 2,
A semiconductor layer 6 made of, for example, amorphous Si is formed in that portion. By forming the drain electrode 3A and the source electrode 5A on the upper surface of the semiconductor layer 6, a so-called inverted staggered thin film transistor having a part of the gate line 2 as a gate electrode is formed. Here, the drain electrode 3A and the source electrode 5 on the semiconductor layer 6
A is formed simultaneously with the pixel electrode 5 when the drain line 3 is formed, for example. That is, the drain line 3 formed of, for example, a chromium layer extends in the y direction in the drawing.
Is formed, and a drain electrode 3A formed integrally with the drain line 3 is formed on the semiconductor layer 6. Here, as shown in the figure, the drain line 3 is formed, for example, on the left side of the pixel region, and has a region that substantially functions as a pixel as large as possible. Further, the source electrode 5A is formed simultaneously with the drain line 3, and is formed integrally with the pixel electrode 5 at this time. The pixel electrodes 5 extend in the y direction in the figure so as to run between the above-described counter electrodes 4A, and are formed, for example, two in the x direction in the figure. In other words, the opposing electrodes 4A are arranged on both sides of the pixel electrode 5 at substantially equal intervals, and an electric field is generated between the pixel electrode 5 and the opposing electrode 4A. Here, as will be clear from the figure, the pixel electrode 5 is formed as a bent electrode in which a 'く' -shaped pattern is repeated along its longitudinal direction. Each of the opposed electrodes 4A facing each other is also a bent electrode (central electrode) in which a “く” -shaped pattern is repeated so as to be separated from the pixel electrode 5 in parallel or an electrode whose width changes ( (An electrode adjacent to the drain line 3). As a result, the direction of the electric field E generated between the pixel electrode 5 and the counter electrode 4A changes with respect to the x direction in the drawing.
There will be a region with (−) θ and a region with (+) θ. As described above, the direction of the electric field E in the area of one pixel (not necessarily in the area of one pixel, and may be in relation to other pixels) is a fixed initial alignment direction. In contrast, the object is to change the light transmittance by rotating the liquid crystal molecules in opposite directions. With this configuration, the inconvenience due to the viewing angle dependence of the liquid crystal display panel, which causes the luminance to be reversed when the viewpoint is inclined at an angle to the main viewing angle direction of the liquid crystal display panel, is eliminated. Such a configuration is called a so-called multi-domain system.

In this embodiment, the initial alignment direction of the liquid crystal molecules has an angle θ ₃ (for example, about 15 °) with respect to the extending direction (y direction) of the drain line 3. That is, the rubbing direction in the alignment film described later is formed so as to match the initial alignment direction. That is, the initial alignment direction of the liquid crystal molecules is set so as not to be coincident with the extending direction of the drain line 3 (or the gate line 2). The reason for this is that, when forming an orientation film described later, if the rubbing direction is the same as the drain line 3, the rollers run in the rubbing process cause each of the gate lines 2 to have its own rubbing direction. This is to prevent static electricity from entering the gate line 2 at once, and to prevent the thin film transistor TFT formed on the gate line 2 from being electrostatically damaged. That is, as in the present embodiment, as long as the running of the roller in the rubbing process is performed at an angle with respect to the gate line 2, the running of the roller on the specific gate line 2 gradually increases from one end to the other end. Therefore, even if static electricity from the roller enters, the thin film transistor TFT can be prevented from being damaged by static electricity. As another reason, as shown in FIG. 4, when rubbing the alignment film, a mask 50 having an opening in a display area, which is a group of pixels, is arranged. A rubbing process is performed along the initial orientation direction (arrow A in the figure). Although the mask 50 itself is formed of a very thin material (about 0.1 mm to 0.3 mm), Travel (1000 ~
This is because the mask 50 is hardly peeled off at 1500 rpm. That is, when rubbing is performed along the drain line 3, the roller must run from one side of the opening of the mask to the opposite side, and the opposite side is easily peeled off. When the rubbing process is performed at an angle with respect to the mask 50, the roller 60 travels from one corner of the opening of the mask 50 to the opposite angle, and can travel while pressing each side constituting the opening. is there.

The direction of the electric field in the pixel with respect to the initial alignment direction of the liquid crystal is set to an appropriate value from the display characteristics. For this reason, when the initial orientation direction of the liquid crystal is set to have the angle θ ₃ with respect to the drain line 3 as described above, the above-described electric field direction θ and (−) θ are appropriately set accordingly. Is set to The portion of the pixel electrode 5 that overlaps the counter voltage signal line 4 is formed so as to increase the area thereof, and a capacitor Cadd is formed between the pixel electrode 5 and the counter voltage signal line 4. The dielectric film in this case is the above-mentioned insulating film. This capacitive element Cadd is, for example, a pixel electrode 5
Is formed in order to accumulate the video signal supplied to the CPU for a relatively long time. That is, when the scanning signal is supplied from the gate line 2, the thin film transistor T
The FT is turned on, and the video signal from the drain line 3 is supplied to the pixel electrode 5 via the thin film transistor TFT.
Thereafter, even when the thin film transistor TFT is turned off,
The video signal supplied to the pixel electrode 5 is applied to the capacitive element Cadd.
Is to be accumulated. A protective film (not shown) made of, for example, a silicon nitride film is formed on the entire surface of the transparent substrate 1 thus formed,
For example, direct contact of the thin film transistor TFT with the liquid crystal can be avoided. Further, an alignment film (not shown) that determines the initial alignment direction of the liquid crystal is formed on the upper surface of the protective film. This alignment film is coated with, for example, a synthetic resin film, and the drain line 3 is formed on the surface thereof as described above.
Is formed by performing a rubbing process in a direction having an angle θ ₃ with respect to the extending direction of. The transparent substrate whose surface has been processed in this manner is called a so-called TFT substrate 1A, and a liquid crystal is interposed on a surface on which the alignment film is formed, and a transparent substrate called a filter substrate is arranged to face the liquid crystal. The display panel is completed. On the filter substrate, a black matrix defining the outline of a pixel area on the liquid crystal side surface, a color filter formed in an opening of the black matrix (corresponding to a central part excluding the periphery of the pixel area), and a liquid crystal. An alignment film or the like formed so as to be in contact is formed.
Here, the alignment film on the filter substrate side is coated with, for example, a synthetic resin film, similarly to that on the TFT substrate 1A side, and the surface thereof is subjected to the rubbing treatment along the extending direction of the drain lines 3 as described above. Is formed by In the so-called in-plane switching mode liquid crystal display device, the alignment directions of the respective alignment films disposed via the liquid crystal are substantially the same, and in the present embodiment, the direction is the extending direction of the drain line 3. Has an angle θ ₃ with respect to. As described above, according to the liquid crystal display device of this embodiment, the electrostatic breakdown of the thin film transistor TFT can be avoided and the mask can be prevented from peeling off during the rubbing treatment of the alignment film.

Embodiment 2 FIG. 2 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. 1 is different from FIG. 1 only in the pattern of the pixel electrode 5 and the counter electrode 4A, and has the same configuration including the angle θ ₃ of the initial alignment direction of the liquid crystal.
That is, there are two types of directions of the electric field generated between the pixel electrode 5 and the counter electrode 4A, _one of which has an angle of θ ₁ with respect to the gate line 2 and the other has an angle of θ ₂ (2θ ₁ ). Angle. In order to obtain proper display characteristics of the liquid crystal, the relationship between these electric field directions θ ₁ and θ ₂ (≠ θ ₁ ) and the angle θ ₃ of the initial alignment direction of the liquid crystal is set so as to satisfy the following expression (1). Have been.

[0010]

Equation 1 θ ₃ = (180 ° −θ ₁ + θ ₂ ) / 2 (1) From this equation (1), for example, the values of θ ₁ , θ ₂ , and θ ₃ are 20 °, It can be set to 10 ° and 85 °. Also in this case, since the initial alignment direction of the liquid crystal is set so as not to coincide with the extending direction of the drain line 3 as in the first embodiment, the electrostatic breakdown of the thin film transistor TFT can be avoided, and Disturbance in the rubbing treatment of the film can be prevented. The above equation (1) shows the relationship between the initial liquid crystal orientation direction θ ₃ and the electric field directions θ ₁ and θ ₂ with respect to the direction orthogonal to the drain line 3 (the extending direction of the gate line 2). is there.
However, the initial alignment direction of the liquid crystal is defined as θ ₃ ′ (≠ 0) with respect to the extending direction of the drain line 3, and the electric field directions θ ₁ ′ and θ ₂ ′ are defined with respect to the initial alignment direction of the liquid crystal. It goes without saying that the setting may be made as follows. The relational expression in this case can be expressed as the following expression (2).

[0011]

[Equation 2] θ ₁ '+ θ ₂ ' = 180 ° [Embodiment 3] FIG. 3 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. It is a drawing. The figure shows that the relationship between the two types of electric field directions θ ₁ and θ ₂ (≠ θ ₁ ) generated between the pixel electrode 5 and the counter electrode 4A and the angle θ ₃ of the initial alignment direction of the liquid crystal is expressed by the above equation (1). Is the same as above, but in particular, θ ₂ = 0 °
Has a difference. Therefore, θ ₁ = 30
If θ, θ ₃ = 75 °, and if θ ₁ = 10 °, θ ₃ = 85 °. By setting θ ₂ = 0 °, the sides of the pixel electrode 5 and the counter electrode 4A facing the other electrode are formed parallel to the extending direction of the drain line 3 in each case. This makes it difficult for the pattern remaining to be generated in the formation of the pixel electrode 5 or the counter electrode 4A by selective etching by the photolithographic technique, and has an effect of improving the product yield.

Incidentally, the first and second embodiments described above are used.
Means that the initial alignment direction of the liquid crystal is about 15
This is an explanation of the case where the angle is set to °. However, it goes without saying that the present invention can be applied to a case where the angle is set to about 15 ° with respect to the gate line 2. In this case, the patterns of the pixel electrode 5 and the counter electrode 4A are set so that the angles of the two electric field directions (corresponding to θ ₁ and θ ₂ in FIG. 2) can be set to appropriate values according to the initial alignment direction of the liquid crystal. Needless to say, it is changed.

[Embodiment 4] FIG. 5 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. In FIG. 5, the configuration different from FIG.
The arrangement relationship of the black matrix BM on the filter substrate side with respect to the counter electrode 4A arranged adjacent to the drain line 3 is clarified. That is, the opposing electrodes 4A arranged adjacent to the drain lines 3 are respectively located on the left and right sides in the drawing in the pixel region.
By arranging the counter electrode 4A at such a position, the electric field due to the video signal from the drain line 3 is easily terminated at the counter electrode 4A instead of the pixel electrode 5, thereby suppressing the generation of noise. Each of the pair of opposing electrodes 4A (the opposing electrode disposed on the center side of the pixel region is not targeted) is connected to the other opposing electrode 4A.
It is formed of a concavo-convex pattern that is in mesh with the sides on the side. For example, as shown in the figure, the uneven pattern is formed by a combination of straight lines having a bending point at the peaks and valleys, and has a so-called zigzag shape. In the case of this embodiment, since the unit pixel employs a so-called multi-domain system in which two types of electric field directions exist between the pixel electrode 5 and the counter electrode 4A, the concavo-convex pattern of the counter electrode 4A is different from that described above. 4A and pixel electrode 5
Is formed so that the width of each electrode is equal.

In this embodiment, in each of the opposing electrodes 4A adjacent to the drain line 3, the side on the drain line 3 side is not formed with the above-mentioned uneven pattern, and is parallel to the drain line 3. Is formed. This is because the region between the drain line 3 and the opposing electrode 4A adjacent to the drain line 3 is made as narrow as possible, so that light leakage caused by an electric field generated therebetween is easily blocked by a black matrix BM described later. The black matrix BM formed on the filter substrate side has an opening side (boundary) in a relationship parallel to the drain line 3 and a drain line 3.
Are located between the peaks and valleys of the concavo-convex pattern of each opposing electrode 4A adjacent to. In other words, the black matrix BM exposes the convex portion of the unevenness formed on the counter electrode 4A adjacent to the drain line 3,
It is formed so as to shield the concave portion. Ideally, the positional relationship between each of the counter electrodes 4A and the black matrix BM is such that the sides of the opening of the black matrix BM are positioned on the central axis of the concavo-convex pattern of each of the counter electrodes BM. It is desirable.

The liquid crystal display device having the above-described structure has a T
When aligning the FT substrate 1A with the filter substrate, as shown in FIG. 6, even when a slight positional shift occurs, particularly in a direction perpendicular to the drain line 3 (extending direction of the gate line 3). This has the effect of avoiding a significant change in the aperture ratio. In other words, the light transmission region in the opening of the black matrix BM can be maintained almost unchanged. Furthermore, in other words, the maximum amount of light transmitted through the opening of the black matrix BM can be maintained substantially unchanged. The reason for this is that, when the filter substrate is displaced with respect to the TFT substrate 1A, as shown in FIG. 6, the convex portion on one counter electrode 4A side is more exposed from the opening of the black matrix. If this is the case (only this portion is viewed, the aperture ratio is reduced), at the same time, the convex portion on the other counter electrode 4A side is more shielded from the opening portion of the black matrix (only this portion is viewed, the aperture ratio is reduced). Is increased).

For this reason, in the above-described embodiment, the pattern of the counter electrode 4A is not limited to the pattern shown in the drawing, and each of the counter electrodes 4A is shielded from the portion exposed from the black matrix. Various patterns can be adopted as long as it satisfies the following conditions. For example, the concavo-convex pattern may have a shape similar to a sine wave or a pulse wave.

[Embodiment 5] FIG. 7 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. The configuration different from that in FIG. 5 is that, also in the black matrix BM, a concavo-convex pattern is formed on the opening side along the counter electrode 4A adjacent to the drain line 3. In this case, the concavo-convex pattern of the black matrix BM is formed in such a manner that a pair of sides on which the black matrix BM is meshed with each other, and has a zigzag shape formed by a combination of line segments having a bending point as in the case of the counter electrode 4A. Has become. And black matrix B
M is arranged such that the convex portion of the opposing electrode 4A is exposed in the concave portion, and the concave portion of the opposing electrode 4A is shielded in the convex portion. Even with this configuration,
If the filter substrate is displaced with respect to the TFT substrate 1A, even if more convex portions are exposed from the opening of the black matrix on one counter electrode 4A side, at the same time, the other counter electrode 4A The convex portion on the side is more shielded from the opening of the black matrix, and the change in the substantial aperture ratio can be greatly reduced.

Embodiment 6 FIG. 8 is a plan view showing another embodiment of the liquid crystal display device according to the present invention. In each of the fourth embodiment and the fifth embodiment, the multi-domain system is applied in any of the above embodiments. In this embodiment, a liquid crystal display device to which the multi-domain system is not applied is shown. That is, the pixel electrode 5 and the counter electrode 4A
In either case, the electrodes extend along one direction (the y direction in the figure), and the direction of the electric field generated between the electrodes is set to a single direction (the x direction in the figure). Therefore, each of the opposing electrodes 4A adjacent to the drain line 3 extends in the y direction similarly to the other electrodes, and the sides in the extending direction are linear. On the other hand, in the black matrix BM on the filter substrate side, a concavo-convex pattern is formed on each opening side along the counter electrode 4A adjacent to the drain line 3 in such a manner that they mesh with each other. The concavo-convex pattern has a zigzag shape composed of a combination of line segments having bending points. In this case, T
When the position of the filter substrate is shifted with respect to the FT substrate 1A, one of the counter electrodes 4A is
Even if it becomes more exposed from the concave part,
The other counter electrode 4A is more shielded by the projections of the black matrix BM.

[Embodiment 7] FIG. 9 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. The configuration different from that of FIG. 8 is that the black matrix BM on the filter substrate side
Is that an uneven pattern is formed on each opening side along the opposing electrode 4A adjacent to the pattern so that they do not mesh with each other. That is, the concave portion formed on one opening side faces the concave portion formed at a location facing the other opening side, and the concave portion formed on the other opening side faces the one opening side. It is in a relationship facing the concave portion formed at the location. Even in this case, if the filter substrate is misaligned with respect to the TFT substrate 1A,
Even if one of the opposing electrodes 4A is more exposed from the concave portion of the black matrix BM, at the same time, the other opposing electrode 4A is more shielded by the convex portion of the black matrix BM.

In each of the fourth to seventh embodiments, a case in which a black matrix is formed on the transparent substrate side opposite to the transparent substrate on which the electrodes are formed is described. However, even when the black matrix is partially or entirely formed on the transparent substrate side on which the electrodes are formed,
It goes without saying that an effect can be obtained by configuring the electrode or the black matrix as a pattern as described above. This is because in such a case, the adverse effect caused by the misalignment between the electrode and the black matrix mask can be eliminated.

[Embodiment 8] FIG. 10 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and is an enlarged view of a portion indicated by a dotted circle A shown in FIG. That is, the pixel electrode 5 formed to have a bent portion in the middle of the extending direction.
And a counter electrode 4A formed at a position where the pixel electrode 5 is shifted in parallel. As described above, the different extending directions of the respective electrodes with respect to the line (virtual line α) shown in the drawing occur between the pixel electrode 5 and the counter electrode 4A as described above. The so-called multi-domain method has been adopted to eliminate the inconvenience due to the viewing angle dependence of the liquid crystal display panel, in which the direction of the electric field is made different and the viewpoint is tilted obliquely with respect to the main viewing angle direction of the liquid crystal display panel, which causes the inversion of brightness. Because it is. Then, in this embodiment, the side edges of the counter electrode 4A has an open angle theta ₅ above 180 ° in the bending portion of the pixel electrode 5, in this part, in the bending portion of the counter electrode 4A It has an arc shape centered on the bending point O on the side of the pixel electrode 5. In this manner, the electric field generating area EA between the pixel electrode 5 and the counter electrode 4A, through which light can pass, is formed.
Are all widths along the longitudinal direction (shortest distance l between electrodes:
(Corresponding to the direction of the electric field). In other words, by forming an arc-shaped pattern at the bent portion of the pixel electrode 5, the electric field intensity of the electric field generation region at that portion can be made substantially equal to the electric field intensity of the electric field generation region at the other portion. Conventionally, the pixel electrode 5 is formed in the pattern shown by the dotted line in the drawing, so that the shortest distance between the electrodes at the bent portion is larger than that of the other portions, and the electric field shown by the scattered area in the drawing. The electric field strength of the generation area EA ′ was weaker than the electric field strength of the other part of the electric field generation area EA. For this reason, when the liquid crystal to be used is so-called normally white (white display in a state where no electric field is applied), even if an attempt is made to display black, a phenomenon occurs in which the portion becomes bright and the contrast is reduced. Further, when the liquid crystal is a so-called normally black (black display in a state where no electric field is applied), even when an attempt is made to display white, a phenomenon has occurred in which this portion is darkened and light transmittance is reduced. In the above-described embodiment, the arc-shaped pattern is formed at the bent portion of the pixel electrode 5. However, the positions of the pixel electrode 5 and the counter electrode 4A are switched, and the counter electrode 4A Is positioned on the right side in the figure, it goes without saying that an arc-shaped pattern may be formed at the bent portion of the counter electrode.

Embodiment 9 FIG. 11 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. The figure shows a pattern in which the side on the side of the counter electrode 4A protrudes toward the counter electrode 4A at the bent portion of the pixel electrode 5, in other words, the bending point O of the counter electrode 4A is defined as the vertex. The width between the electrodes in this portion is reduced by forming a straight line pattern corresponding to the base of the triangle. in this case,
As in the ninth embodiment, the distance between the pixel electrode 5 and the counter electrode 4A in the bent portion does not exactly match the distance between the pixel electrode 5 and the counter electrode 4A in the other portions, and the pixel in the bent portion The strength of the electric field between the electrode 5 and the counter electrode 4A is increased. The reason why the electric field at the bent portion is particularly stronger than that at the other portion is that the direction of the electric field is different at this portion and the liquid crystal is more difficult to rotate than the other portions. It is resolved so that a decrease in contrast or a decrease in light transmittance is suppressed.

[Embodiment 10] FIG. 12 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. This figure is different from FIG. 10 in that the corner of the side of the bent side of the counter electrode 4A on the side of the pixel electrode 5 is also arc-shaped. That is, at the bent portion of each electrode, the side of each electrode facing the other electrode is formed so as to draw a smooth arc. In other words, the electric field generating region E between the pixel electrode 5 and the counter electrode 4A.
A has different extending directions so as to be curved in the middle thereof, and its width 1 is formed uniformly along the extending direction. In this case, similarly to FIG. 10, the intensity of the electric field generated in the pixel electrode 5 and the counter electrode 4A can be made uniform in all of them.
Then, since there is no corner on the side of each of the electrodes facing the other electrode, it is possible to avoid the occurrence of electric field concentration at this corner.

[Embodiment 11] Embodiments 8 to 10
Describes that the electric field intensity at the bent portion of the pair of electrodes is made substantially equal to the electric field intensity at a portion other than the bent portion. However, without intending this, the 180 formed at the bent portion of the pair of electrodes is not required.
Needless to say, the corners of less than or equal to ° may be formed in an arc-shaped pattern. By doing so, the effect that concentration of the electric field can be avoided is achieved.

[0025]

As is apparent from the above description,
According to the liquid crystal display device of the present invention, it is possible to avoid a decrease in light transmittance or a decrease in contrast.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 3 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 4 is a diagram illustrating an effect of the liquid crystal display device according to the present invention.

FIG. 5 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 6 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

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

FIG. 8 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 9 is a plan view showing another embodiment of the pixel of the liquid crystal display device according to the present invention.

FIG. 10 is a plan view showing an embodiment of an electrode of the liquid crystal display device according to the present invention.

FIG. 11 is a plan view showing another embodiment of the electrode of the liquid crystal display device according to the present invention.

FIG. 12 is a plan view showing another embodiment of the electrode of the liquid crystal display device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 1A ... TFT substrate, 2 ... Gate line, 3 ...
Drain line, 4 ... counter voltage signal line, 4A ... counter electrode, 5
... Pixel electrode, 6 semiconductor layer, TFT thin film transistor, Cadd capacitor element, BM black matrix.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Keiichiro Ashizawa 3300 Hayano, Mobara City, Chiba Prefecture Within Hitachi, Ltd. Display Group (72) Inventor Masayuki Hikiba 3300 Hayano, Mobara City, Chiba Prefecture, Hitachi, Ltd. F term (reference) 2H092 GA13 HA02 JA24 JA26 JB51 KA05 NA14 NA18 NA22 NA29 PA01 PA08 QA05

Claims (15)

[Claims] An electric field generating region for generating an electric field parallel to a substrate is provided. The electric field generating regions have regions in which directions of electric fields are different from each other. A liquid crystal display device characterized in that the electric field intensity is substantially the same as that of the region. 2. An electric field generating region for generating an electric field parallel to a substrate, the electric field generating region having a bent portion and extending in different directions, and an electric field at the bent portion. A liquid crystal display device characterized in that the electric field intensity in the generation region is substantially equal to the electric field intensity in the electric field generation region in other parts. 3. An electric field generating region between a pair of electrodes for generating an electric field parallel to the substrate, wherein the electric field generating region is a region where its extending direction changes on the way. A liquid crystal display device, wherein the shortest distance between a pair of electrodes in the electric field generation region is formed uniformly along the extending direction of the electric field generation region. 4. A pixel region on a liquid crystal side surface of one of the substrates,
A pixel electrode formed with a bent portion in the middle of the extending direction, and a counter electrode formed at a position shifted parallel to the pixel electrode, wherein an angle of 180 ° or more of the pixel electrode and the counter electrode. Wherein the bent portion on the electrode side having the following is formed in an arc pattern. 5. A pixel electrode having a bent portion in the middle of an extending direction, and a counter electrode formed at a position shifted in parallel with the pixel electrode, wherein the pixel electrode and the counter electrode are respectively A liquid crystal display device, wherein the bent portions on the side of the electrode facing each other are formed in an arc pattern. 6. A pair of substrates, comprising: a pair of parallel electrodes formed on a liquid crystal side surface of one of the substrates to generate an electric field; an electric field generating region between these electrodes has a bent portion; A liquid crystal display device, wherein at least one of the electrodes is formed as a pattern in which the electric field intensity at the bent portion is substantially the same as the electric field intensity at other portions. 7. An electric field generating region between a pair of electrodes formed on a liquid crystal side surface of one of the substrates to generate an electric field has a bend, and by reducing the width of the electric field generating region in the bend, A liquid crystal display device wherein the intensity of the electric field is higher than that of the portion other than the bent portion. And a pair of parallel electrodes formed on a liquid crystal side surface of one of the substrates to generate an electric field, wherein the electrodes are formed to bend at a virtual line as a boundary. The liquid crystal display device is characterized in that the distance between the electrodes in the vicinity of the line is substantially equal to the distance between the electrodes in other portions. 9. The liquid crystal display device according to claim 8, wherein the distance between the electrodes is the shortest distance between the electrodes. 10. A surface on the same substrate side, comprising: a bent pixel electrode; and a bent counter electrode formed at a position translated in parallel with the pixel electrode. A portion having an opening angle of 180 ° or less on the side of the other electrode side in the bent portion of the electrode has an arc shape centered on a vertex in the bent portion of the other electrode. Liquid crystal display device. 11. A pixel electrode formed in a pixel region on a liquid crystal side surface of one of the substrates so as to have a bent portion in the middle of an extending direction, and a counter electrode formed at a position where the pixel electrode is shifted in parallel. A liquid crystal display device comprising: an electrode, wherein, of the pixel electrode and the counter electrode, the bent portion on the electrode side having an angle of 180 ° or less is formed in an arc pattern. 12. An electric field generating region for generating an electric field parallel to the substrate, and a liquid crystal which displays black when no electric field is applied, wherein the electric field generating region has a bent portion. A liquid crystal display device having regions extending in different directions, and wherein the electric field intensity of the electric field generation region at the bent portion is substantially equal to the electric field intensity of the electric field generation region at other portions. 13. An electric field generating region for generating an electric field parallel to a substrate, and a liquid crystal which displays white when no electric field is applied, wherein the electric field generating region has a bent portion. A liquid crystal display device having regions extending in different directions, and wherein the electric field intensity of the electric field generation region at the bent portion is substantially equal to the electric field intensity of the electric field generation region at other portions. 14. The electric field generation region according to claim 1, wherein the electric field generation region is a region between a pair of electrodes formed on the substrate side and light can pass through the substrate.
7. The liquid crystal display device according to 7, 12, 13, or 14. 15. A video signal from a drain line via a switching element driven by a scanning signal from a gate line, on a liquid crystal side surface of one of the transparent substrates opposed to each other via a liquid crystal. Is provided, and a counter electrode that generates an electric field between the pixel electrode and the pixel electrode. A region between these electrodes has a bent portion in the middle of the extending direction, A liquid crystal display device characterized in that the electric field strength is substantially equal to the electric field strength in other parts.