JP2000305095A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dielectric breakdown of a switching device by controlling the initial alignment direction of a liquid crystal to make an angle from the signal line which supplies signals to an electrode to generate an electric field. SOLUTION: A signal as the reference for a video signal to be supplied to pixel electrodes 5 is supplied through a counter voltage signal line 4 to a counter electrodes 4A so as to generate an electric field of the intensity corresponding to the video signal between the counter electrodes and the pixel electrodes 5. The pixel electrodes 5 are formed as bent electrodes along the longitudinal direction, and each counter electrode 4A facing the pixel electrode is formed as a bent electrode or an electrode having varying width parallel to the pixel electrodes 5 with a space. This results in the presence of such regions that the direction of the electric field E generated is at -θ or +θ angle from the x-direction and that liquid crystal molecules are rotated in the opposite directions to a specified initial aligning direction to change the transmittance for light. For example, the initial alignment direction of the liquid crystal molecules is at an angle θ from the extended direction of a drain line 3.

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, and more particularly, to a liquid crystal display 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 become 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. Such a configuration is called a so-called multi-domain system,
The inconvenience due to the viewing angle dependence of the liquid crystal display panel, which causes the brightness to be inverted when the viewpoint is tilted with respect to the main viewing angle direction of the liquid crystal display panel, is solved. In the horizontal electric field type liquid crystal display device, the alignment films formed on the transparent substrates opposed to each other with the liquid crystal interposed therebetween can have the same rubbing direction (initial alignment direction of the liquid crystal) in any of them. Each direction of the electric field is set to an appropriate direction based on the initial alignment direction of the liquid crystal. As a specific example, the initial alignment direction of the liquid crystal is set in parallel with the drain line that supplies a video signal to each pixel, whereby the pixel electrode in the pixel region and the opposing electrode arranged in parallel with this pixel electrode are set. Are formed so as to extend in a zigzag manner in the direction of the drain line.

[0003]

However, it has been pointed out that the liquid crystal display device constructed as described above has a very high probability of causing electrostatic breakdown in switching elements formed for each pixel. . That is, the switching element is formed so as to overlap with the gate line arranged to intersect with the drain line, and when the rubbing process is performed using a roller on the alignment film, the direction of the rubbing process is the extending direction of the drain line. Therefore, there is a concern that static electricity may enter through the entire gate line at one time due to the contact of the roller. Further, the rubbing treatment of the alignment film is performed through an extremely thin mask provided with an opening in a region corresponding to a display portion which is an aggregate of pixels. Since they are aligned in the axial direction, there is also a disadvantage that the opposite side is peeled off near the end of the rubbing process by the roller. 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 can prevent electrostatic breakdown of a switching element. Another object of the present invention is to provide a liquid crystal display device capable of preventing a mask from peeling off during a rubbing process.

[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, the light transmittance of the liquid crystal is controlled by an electric field generated in parallel with the substrate, and the electric field has two or more directions, and the initial alignment direction of the liquid crystal supplies a signal to an electrode for generating the electric field. The signal line has an angle with respect to the signal line. The liquid crystal display device thus configured is of a multi-domain type, and the initial alignment direction of the liquid crystal is as follows.
It is configured to have an angle with respect to the signal line. Therefore, even if a rubbing process is performed on the alignment film along the initial alignment direction of the liquid crystal, the roller runs in a direction oblique to the signal line. This makes it possible to avoid the contact of the roller with the signal line (an insulating film or the like may be interposed) at one time, and to prevent the switching element such as a thin film transistor from being broken by the intrusion of static electricity by the roller. Will be able to Further, when the rubbing treatment is performed via a mask, the rollers travel so as to have an angle with respect to the opening side of the mask, that is, from one corner of the opening of the mask facing the other to the other. , The peeling at the opening side of the mask can be suppressed.

[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 prevent the switching element from being damaged by static electricity. In addition, the mask can be prevented from peeling off during the rubbing process.

[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: Capacitance 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 GA14 JA26 JA29 JA38 JA42 JB11 JB23 JB32 JB38 NA01 NA14 NA25 PA06 QA06 QA18

Claims (14)

[Claims] An electric field generated in parallel with a substrate controls the light transmittance of a liquid crystal. The electric field has two or more directions, and an initial alignment direction of the liquid crystal is controlled by an electrode for generating the electric field. A liquid crystal display device having an angle with respect to a signal line for supplying a signal. 2. A semiconductor device comprising: a pair of electrodes formed in a pixel region of one substrate; and a signal line for supplying a signal to the electrodes, wherein each of the electrodes has a minimum distance of two or more directions. And an initial alignment direction of the liquid crystal is not matched with an extending direction of the signal line. 3. A liquid crystal side surface of one of the substrates, a signal line formed surrounding a pixel region, and an opposing electrode for generating an electric field between the pixel electrode formed in the pixel region and the pixel electrode. Wherein the direction of the electric field between the pixel electrode and the counter electrode is two or more with respect to the initial alignment direction of the liquid crystal set at an angle with respect to the signal line. Liquid crystal display device. 4. An electric field generating means formed by generating an electric field parallel to the substrate and directing the electric field in two or more directions, and a signal line connected to the electric field generating means. A liquid crystal display device comprising: an alignment film in which an initial alignment direction of liquid crystal is set so as to be different from an extending direction of the signal line. 5. A pair of electrodes formed in a pixel region of one substrate, a drain line for supplying a video signal to one of the electrodes via a switching element, and a gate line for driving the switching element Wherein each electrode has two or more directions of the separation distance, and the initial alignment direction of the liquid crystal is not matched with the extending direction of the drain line and the gate line. Characteristic liquid crystal display device. 6. The liquid crystal device according to claim 1, wherein an initial alignment direction of the liquid crystal interposed between the opposed substrates is set to one direction, and the initial alignment direction of the liquid crystal has an angle with respect to a side of the substrate. A liquid crystal display device having two or more directions of an electric field for controlling the light transmittance of the liquid crystal. 7. A liquid crystal whose initial alignment direction is set to one direction, an electric field generating means having two or more electric field directions for controlling the light transmittance of the liquid crystal, and a signal is supplied to the electric field generating means. And a signal line formed at an angle with respect to the initial alignment direction of the liquid crystal. 8. The light transmittance of the liquid crystal is controlled by an electric field generated in parallel with the substrate, and the electric field is controlled in a direction perpendicular to a drain line for supplying a video signal to an electrode for generating the electric field. +) Θ,
(−) Θ direction, and the initial alignment direction of the liquid crystal has an angle θ ₀ with respect to the drain line, and the angle θ ₀ is 0 ° <θ ₀ <parallel to the electrode. A liquid crystal display device characterized by satisfying an angle relationship. 9. A semiconductor device comprising: a pair of electrodes formed in a pixel region on a liquid crystal side of one substrate; and a drain line for supplying a signal corresponding to an electric field generated between the pair of electrodes. The liquid crystal is formed in a zigzag shape with a line parallel to the drain line as a central axis.
A liquid crystal display device having ₀ , and satisfying a relationship of 0 ° <θ ₀ <angle parallel to an electrode. 10. The liquid crystal display device according to claim 9, wherein each of the electrodes is formed by a combination of a plurality of line segments having a bending point. 11. A light transmittance of liquid crystal is controlled by an electric field generated in parallel to the substrate, and the electric field is θ with respect to a direction orthogonal to a drain line for supplying a video signal to an electrode for generating the electric field. ₁ , θ ₂ (≠
It has a direction of theta _1), and the initial orientation direction of the liquid crystal, as well as has an angle relative to the drain line, ₃ an angle theta with respect to a direction perpendicular to the said Doiren line
A liquid crystal display device satisfying the following relationship: θ ₃ = (180 ° −θ ₁ + θ ₂ ) / 2. 12. A pair of electrodes formed in a pixel region of one substrate, and a drain line for supplying a video signal to one of the pair of electrodes via a switching element.
And a gate line formed to intersect the video signal and drive the switching element. The distance between the pair of electrodes is θ ₁ , θ ₂ (≠ θ _{1) with} respect to the gate line. ), And the initial alignment direction of the liquid crystal is not matched with the extending direction of the drain line. If the angle with respect to the gate line is θ ₃ , then θ ₃ = (180 ° −θ ₁₎ A liquid crystal display device having a relationship of + θ ₂ ) / 2. 13. One of the substrates is provided with at least a pair of electrodes for generating an electric field in a pixel region surrounded by an adjacent drain line and an adjacent gate line, and the extending direction of the drain line or the gate line. The initial alignment direction of the liquid crystal is set to a direction having an angle with respect to, and the pair of electrodes is formed to have two or more types of extending directions with respect to the initial alignment direction of the liquid crystal. A liquid crystal display device characterized by the above-mentioned. 14. A pixel region surrounded by a drain line and a gate line adjacent to each other on a liquid crystal side of one substrate, and at least one pair formed on the one substrate side in the pixel region. The direction of the electric field between the pair of electrodes is θ ₁ ′ + θ ₂ ′ with respect to the initial alignment direction of the liquid crystal having an angle θ ₃ ′ (≠ 0) with respect to the gate line. = 180 °, a liquid crystal display device having angles of θ ₁ ′ and θ ₂ ′.