JP2000314890A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the alignment property of liquid crystal concerning a liquid crystal display device. SOLUTION: The liquid crystal display device comprises a liquid crystal whose molecules pretilt and twist in accordance with alignment treatment of a first alignment layer 22 and a second alignment layer 26. The first alignment layer 22 and the second alignment layer 26 are provided with a first and a second liquid crystal alignment segments A, B formed in each of plural microunit regions. The major axes of the liquid crystal molecules are extended in parallel directions and are pretilted in the reverse directions. Besides parts 22p, 26p of the first alignment layer 22 and the second alignment layer 26 corresponding to a boundary part of the first and the second liquid crystal alignment segments A, B are constructed to be formed in such deformed shapes as to be protruded or recessed with respect to the thickness direction of the liquid crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device comprises a liquid crystal panel in which liquid crystal is inserted between a pair of opposed transparent substrates. A common electrode and an alignment film are provided on the inner surface of one glass substrate,
A pixel electrode and an alignment film are provided on the inner surface of the other substrate. Recently, active matrix circuits are often formed together with pixel electrodes on the latter substrate. Further, a polarizing plate is provided outside each of these substrates. Usually, these polarizing plates are arranged so that transmission axes of polarized light are orthogonal to each other.

[0003] Twisted nematic liquid crystals are often used in liquid crystal display panels. The liquid crystal molecules pretilt and twist according to the alignment films of both substrates. In other words, the major axis direction of the molecules of the liquid crystal extends in parallel with the orientation direction of the alignment film of the substrates, and the orientation directions of the alignment films of the two substrates are substantially perpendicular to each other. As it twists in a spiral. It is also known that liquid crystal molecules pretilt according to the orientation direction.

The alignment of the liquid crystal is achieved by rubbing the alignment film in a predetermined direction, and the rubbing direction matches the alignment direction of the liquid crystal. The orientation of the liquid crystal is
For example, it can be controlled by forming the alignment film by oblique evaporation. When no voltage is applied to the liquid crystal, the molecules of the liquid crystal maintain an initial twist and pretilt, and the incident light travels while turning along the twist of the liquid crystal and exits from the liquid crystal cell. At this time, a white display is obtained. When a voltage is applied, the liquid crystal rises, the birefringence effect of the liquid crystal is weakened, and the above-described swirling effect of light is weakened, so that incident light is less likely to pass through the liquid crystal cell, and a black display can be obtained. In this way, an image having a bright and dark contrast as a whole is formed while controlling the voltage applied to the liquid crystal.

When a voltage is applied to the liquid crystal, the molecules of the liquid crystal rise in a direction having a pretilt. actually,
When a voltage is applied, not all molecules of the liquid crystal rise in the same manner, but molecules of the liquid crystal located near the alignment film of the substrate rise only slightly due to the regulation of the alignment film. The rising liquid crystal molecules rise the largest. Therefore, the formation of a black display when a voltage is applied mainly depends on the behavior of the molecules of the liquid crystal positioned at the intermediate portion between the two substrates.

The liquid crystal molecules have a long rod shape,
Because of the anisotropy of the refractive index, the effect of birefringence differs depending on the direction of light incidence. When a voltage is applied, the molecules of the liquid crystal do not rise until they become perpendicular to the surface of the substrate, but rise to a certain angle with respect to the surface of the substrate. Therefore, when the liquid crystal molecules rise to a certain angle with respect to the surface of the substrate due to the application of a voltage, the observer has a difference in the positional relationship with the long axis direction of the liquid crystal molecules depending on the direction in which the screen is viewed. , The degree of black display obtained differs. Therefore, depending on the position of the viewer, the contrast between light and dark in the image is reduced. This is generally recognized as a viewing angle characteristic of a liquid crystal display device.

In order to solve such a problem, Japanese Patent Application Laid-Open No. 54-5754 discloses a method in which two liquid crystal alignment sections having different twist directions of liquid crystal molecules are formed in each small unit area of liquid crystal. Has been proposed. Also, JP-A-63
Japanese Patent No. 106624 proposes forming two liquid crystal alignment sections having different alignment directions of liquid crystal molecules in one pixel. According to these proposals, the overall visual characteristics can be improved by mixing a liquid crystal alignment section having a certain viewing angle characteristic with another liquid crystal alignment section having a different viewing angle characteristic.

[0008]

As described above, when two liquid crystal alignment sections are formed in each of the minute unit regions of the liquid crystal, the liquid crystal molecules are moved in the opposite direction at the boundary between these two liquid crystal alignment sections. There is a problem that the liquid crystal molecules in the two liquid crystal alignment sections hinder each other in a predetermined alignment, and it is difficult to obtain a good alignment. Therefore, there has been a problem that domains and disclinations occur.

An object of the present invention is to provide a liquid crystal display device capable of improving the orientation of liquid crystal.

[0010]

A liquid crystal display device according to the present invention comprises first and second opposed substrates 16, 18, a common electrode 21 provided on the inner surface of the first substrate, and a first electrode. An alignment film 22, a plurality of pixel electrodes 24 and a second alignment film 26 provided on the inner surface of the second substrate, and a liquid crystal 20 inserted between the first and second substrates. Wherein the pixel electrodes are formed such that lines of electric force in oblique directions act on each of the pixel electrodes.

[0011]

In the first configuration described above, the contrast between light and dark is improved by providing the first and second liquid crystal alignment sections for each minute unit area. The pixel electrodes are formed so that the lines of electric force in the oblique direction act on each of the pixel electrodes, and the electric field in the oblique direction improves the orientation of the liquid crystal.

[0012]

3 to 10 illustrate the first and second liquid crystal alignment sections which are the premise of the present invention. FIG. 3 shows a liquid crystal panel 10 of the liquid crystal display device according to the embodiment of the present invention.
FIG. 3 is a diagram showing polarizing plates 12 and 14. LCD panel 1
0 denotes a liquid crystal 2 between a pair of transparent glass substrates 16 and 18.
0 is enclosed. Light from a light source (not shown) enters the liquid crystal panel 10 from the direction of the arrow L, and the viewer E views the liquid crystal panel 10 from a direction opposite to the incident direction.
In the following description, the substrate 16 on the light incident side is referred to as a lower substrate, and the substrate 18 on the viewer side is referred to as an upper substrate.

The inner surface of the lower substrate 16 has a common electrode 2 of ITO on it.
1 and an alignment film 22 are provided, and a pixel electrode 24 and an alignment film 26 are provided on the inner surface of the upper substrate 18. Further, FIG.
Shows a storage capacitor electrode 28 provided between the upper substrate 18 and the pixel electrode 24 via an insulating layer. FIG.
Shows the arrangement of the pixel electrodes 24 and the active matrix circuit provided on the upper substrate 18. The active matrix circuit includes a data bus line 30 and a gate bus line 32 extending vertically and horizontally in a matrix, and the pixel electrode 24 is connected to the data bus line 30 and the gate bus line 32 via a thin film transistor (TFT) 34. 10 shows an equivalent circuit in which the storage capacitor electrode 28 is provided in parallel with the liquid crystal 20.

Referring to FIGS. 3 and 4, the liquid crystal 20 is a twisted nematic liquid crystal. The twisted nematic liquid crystal 20 is composed of an alignment film (lower alignment film) 2 of the lower substrate 16.
2 orientation direction 22a and orientation film of upper substrate (upper orientation film) 2
Twist and pretilt according to the alignment direction 26a of FIG. 6 (FIG. 5). As shown in FIG. 4, the orientation direction 22a of the lower orientation film 22 and the orientation direction 26a of the upper orientation film 26 are substantially parallel to the glass plane and provided in directions perpendicular to each other. The orientation direction 22a of the lower orientation film 22 and the orientation direction 26a of the upper orientation film 26 are determined by using a rubbing material such as fiber when the orientation treatment is performed by rubbing.
a, 26a. Similarly, an alignment film having such an alignment direction can be formed by oblique deposition.

FIG. 4 shows an example in which the molecules of the liquid crystal 20 in a minute area are twisted counterclockwise as indicated by an arrow T. Here, 20L indicates a liquid crystal molecule located near the lower alignment film 22, and 20C indicates a liquid crystal molecule located at an intermediate portion (center of the liquid crystal layer) between the lower alignment film 22 and the upper alignment film 26. , 20U indicate liquid crystal molecules located near the upper alignment film 26.

FIG. 5A is a diagram showing the extracted molecules 20L, 20C, and 20U of the liquid crystal 20.
The left half of FIG. 5A shows the molecules 20 of these liquid crystals 20.
L, 20C, and 20U as viewed from the top of the panel.
FIG. 3C is a cross-sectional view of C and 20U as viewed with upper and lower alignment films 22 and 26. Note that this cross-sectional view is viewed from the direction of the arrow in the figure on the left.

Referring to FIG. 5A, the major axis of the lower molecule 20L of the liquid crystal 20 is oriented in the direction of 45 degrees from the lower right to the upper left in the plan view, and the left end in the sectional view is the lower alignment film 22. This shows a pretilt that rises. Intermediate molecule 20 of liquid crystal 20
The major axis of C is vertically oriented from bottom to top in the plan view, and the cross-sectional view indicates the pretilt whose left end rises. The major axis of the upper molecule 20U of the liquid crystal 20 is oriented in the direction of 45 degrees from the lower left to the upper right in the plan view, and the cross section shows the pretilt in which the right end rises with respect to the upper alignment film 26.

FIG. 5B shows the alignment direction (rubbing direction) 2 of the alignment films 22 and 26 for obtaining the alignment state shown in FIG.
2a and 26a are shown, and solid arrows indicate lower substrate 16
The orientation direction 22a of the orientation film 22 of the upper substrate 18 is indicated by a broken line arrow.
If the two alignment directions 22a and 26a are determined, the alignment of the liquid crystal molecules between them is determined. Therefore, the display of FIG. 5B shows the alignment state of FIG. 5A. Thereafter, the liquid crystal panel 10 having the characteristics shown in FIG.
Is referred to as a liquid crystal alignment section A.

Attention is now paid to the liquid crystal intermediate molecules 20C located at the intermediate portion between the lower alignment film 22 and the upper alignment film 26. When no voltage is applied, the upper and lower liquid crystal molecules 20U, It is oriented almost horizontally like 20L, but rises to a certain angle of inclination as shown by the broken line when voltage is applied. (C) of FIG.
As shown in the arrow E _C represents the view the liquid crystal panel from the normal direction, an arrow E _L, E _U shows a case where each viewed from below and above.

[0020] Looking at the liquid crystal panel from the direction of arrow E _U, the magnitude of the birefringence of the liquid crystal of the intermediate molecules 20C is relatively small, it will see a dark black display. Conversely, this is indicated by arrow E
From the viewpoint of _L , the magnitude of the birefringence of the intermediate molecules 20C of the liquid crystal shows a relatively large value. In this case, since the amount of transmitted light is large, a brighter black display is obtained. As described above, in the case of the liquid crystal alignment section A, the image viewed from above is dark, and the image viewed from below is bright.

The viewing angle characteristic of the liquid crystal alignment section A is shown by a dashed line C and broken lines L and U in FIG. The dashed line C in FIG. 7 is a voltage / transmittance curve when viewed from the front. Dashed lines U and L are voltage / transmittance curves when viewed from above and below at an angle of 40 degrees. In the case of the broken line L, even if the voltage is increased, the transmittance does not decrease much, so that even if an attempt is made to obtain a black display, the display becomes relatively bright. In the case of the broken line U, applying a small voltage greatly reduces the transmittance and immediately turns black, which is inconvenient for obtaining an intermediate color between white and black.

Therefore, the characteristics of the broken line L and the broken line U are added to 2
The solid line I shows the characteristic of dividing by. The characteristics of the solid line I are close to those of the one-dot chain line C, and the viewing angle characteristics are improved. For this reason, as shown in FIG.
A liquid crystal alignment section B having characteristics complementary to the above is provided, and the liquid crystal alignment section A and the liquid crystal alignment section B are combined into one unit. Alignment directions 22a, 26 of alignment films 22, 26 of liquid crystal alignment section B
a are perpendicular to each other and opposite to the alignment directions 22a and 26a of the alignment films 22 and 26 of the liquid crystal alignment section A, respectively. Therefore, the intermediate molecules 20C of the liquid crystal alignment section B rise in voltage application in the opposite manner to the case of the alignment section. Therefore, the viewing angle characteristics of the liquid crystal alignment section B are, as opposed to the liquid crystal alignment section A, bright when viewed from above and dark when viewed from below.

Therefore, the liquid crystal alignment sections A and B
Are arranged together, the characteristic of the solid line I in FIG. 7 is obtained. The combination of the liquid crystal alignment sections A and B is defined as one unit area, and the liquid crystal panel 10 is formed by repeating such minute unit areas. The alignment process of the alignment films 22 and 26 having such characteristics can be performed by, for example, a rubbing process shown in FIG. In FIG. 11, an inorganic alignment film 51 and an organic alignment film 52 are applied to the surface of the upper substrate 18, and a rubbing roller 53 around which a rubbing material such as fiber is wound is rotated in the direction of the arrow as shown in FIG. And proceed in one direction. Next, as shown in (B), the rubbing roller 53 is advanced in a direction different from that of (A) by using the mask 54. Note that the organic alignment film 52 is removed before the process (B). Mask 54
Is formed by a resist by photolithography,
The resist is removed later. In this case, by the process (B), the first rubbed portion under the mask 54 in (A) and the portion rubbed in (B) exposed from the mask 54 are first defined. The rubbed portion corresponds to the liquid crystal alignment section A, and the rubbed portion later corresponds to the liquid crystal alignment section B. The lower substrate 1
The same rubbing is performed on No. 6. In the case where the alignment process is performed by oblique deposition, the alignment process can be similarly performed for each minute section using a mask.

FIG. 6 shows an example in which the liquid crystal alignment section A and the liquid crystal alignment section B are vertically arranged. This is because the liquid crystal alignment section A and the liquid crystal alignment section B are arranged at an intermediate portion between the lower alignment film 22 and the upper alignment film 26. The orientation directions of the intermediate molecules 20C are shown only vertically in order to simultaneously explain them, and are substantially the same as those in which the liquid crystal orientation sections A and B are arranged side by side as shown in FIG. is there. In the above description, the liquid crystal 20 twists counterclockwise. However, as shown in FIG. 9, the liquid crystal 20 is divided into the liquid crystal alignment sections A1 and B1 having the alignment directions 22a and 26a as illustrated. A similar feature can be achieved with a clockwise twist.

The liquid crystal alignment section A and the liquid crystal alignment section B have different viewing angle characteristics. In order to form a uniform image without the difference being recognized by a viewer, the liquid crystal alignment section A and the liquid crystal alignment section B need to have different viewing angle characteristics. It is desirable that the area be small to some extent. Preferably, one unit region is formed so as to coincide with one pixel region surrounded by the data bus line 30 and the gate bus line 32. When a color filter is provided on the lower substrate 16 for color display, one pixel region is a region for each of R, G, and B of the color filter. However, one unit area may be an integral multiple (up to about three times) of one pixel area or a reciprocal multiple of an integer of one pixel area.

When the liquid crystal alignment section A and the liquid crystal alignment section B are provided, the alignment processing must be performed on the same substrate so as to have opposite alignment directions. There was a problem that it was difficult to obtain good alignment at the boundary between the alignment section A and the liquid crystal alignment section B. Therefore, the present invention is further developed to solve such a problem.

Referring to FIG. 1, the liquid crystal display device comprises a repetition of a small unit area composed of the liquid crystal alignment sections A and B having the above-described characteristics, and the liquid crystal alignment sections A and B. Are formed in a deformed shape that protrudes or retreats in the thickness direction of the liquid crystal 20. In FIG. 1, the portion 22p of the alignment film 22 has a concave shape protruding in the thickness direction of the liquid crystal 20, and the portion 2p of the alignment film 26
6p has a convex shape protruding in the thickness direction of the liquid crystal 20.

FIG. 2 shows the alignment directions of the liquid crystal alignment section A and the liquid crystal alignment section B in FIG. 1, which are the alignment directions 22a, 2a and 2a of the liquid crystal alignment section A and the liquid crystal alignment section B described in FIG.
6a. The relationship between the pretilt of liquid crystal molecules is
As shown in FIG. 6, the pretilt of the liquid crystal alignment section A rises to the left and the pretilt of the liquid crystal alignment section B rises to the right in FIG. Is shown as rising to the left, and the pretilt of the liquid crystal alignment section B is shown as rising to the right. However, since the alignment direction 22a of the lower alignment film 22 and the alignment direction 26a of the upper alignment film 26 are perpendicular to each other,
In FIG. 1, the upper alignment film 26 is replaced with the lower alignment film 22 for convenience of explanation.
Is rotated 90 degrees with respect to FIG.

Due to such features, in the concave portion 22p of the alignment film 22, the liquid crystal molecules at the right end of the liquid crystal alignment section A are oriented along the left slope of the concave shape of the portion 22p, and the liquid crystal alignment section B The liquid crystal molecules at the left end of
Oriented along the right slope of the concave shape. Also, the alignment film 2
6, the liquid crystal molecules at the right end of the liquid crystal alignment section A are oriented along the left slope of the convex shape of the section 26p, and the liquid crystal molecules at the left end of the liquid crystal alignment section B are partially aligned. It is oriented along the right slope of the 26p convex shape.

When the liquid crystal 20 is placed along the surface, it tends to be oriented according to the surface. As described above, the deformed portions 22p and 26p of the alignment films 22 and 26 are formed as described above.
Are oriented along. Then, the alignment films 22 and 26
The orientation directions along the portions 22p and 26p of the deformed shape of
The alignment direction originally matches the liquid crystal alignment section A and the liquid crystal alignment section B. Therefore, the deformed portions 22p and 26p of the alignment films 22 and 26 serve to assist the predetermined alignment of the liquid crystal 20 at the boundary between the liquid crystal alignment sections A and B. Therefore, the alignment of the liquid crystal is improved.

FIGS. 12 and 13 show examples in which the deformed portions 22p and 26p of the alignment films 22 and 26 of FIGS. 1 and 2 are formed in combination with the storage capacitor electrode 28 and the color filter 40. FIG. In FIG. 12, the liquid crystal alignment section A
And the unit area forming the liquid crystal alignment section B is formed so as to coincide with one pixel area surrounded by the data bus line 30 and the gate bus line 32, and the boundary between the liquid crystal alignment section A and the liquid crystal alignment section B is defined by the pixel electrode. The gate bus line 32 extends in parallel with the gate bus line 32. The transistor 34 has a redundant configuration and is arranged symmetrically with respect to the center line of the pixel electrode 24. Therefore, the liquid crystal alignment sections A and B are similarly affected by the voltage of the transistor 34.

As shown in FIGS. 12 and 13, the storage capacitor electrode 28 is provided on the surface of the upper substrate 18. ITO
Of the storage capacitor electrode 28 via the insulating layer 40
And an alignment film 26 is further formed thereon. The storage capacitor electrode 28 has a predetermined thickness and width, and has a projection shape on the upper substrate 18. Accordingly, the pixel electrode 24 and the alignment film 26 thereon are similarly formed in a protruding shape, so that a convex portion 26p of the alignment film 26 is formed.
In order to shape the shape of the convex portion 26p of the alignment film 26 as desired, a protrusion 28a may be provided.
The data bus line 30 and the gate bus line 32 can be used to obtain the shape of the convex portion 26p of the alignment film 26.

FIG. 13 shows the lower substrate 16 provided with a color filter 42 for color display. The color filter 42 has pixel regions for each of R, G, and B, and an overcoat 43 is provided thereon. Also,
A black matrix 44 is provided to open R, G, and B pixel regions of the color filter 42. The illustrated two color filters 42 are, for example, both R components, and the black matrix 44 includes the two color filters 4.
2, but is not provided in the gap between the two color filters 42 (however, a black matrix may be provided in this gap.

The gap between the two color filters 42 has a concave shape. The overcoat 43, the common electrode 21, and the alignment film 22 formed thereon also have the same concave shape. Therefore, the concave portion 2 of the alignment film 22
2p and 26p can be formed in combination with the color filter 42. FIG. 14 is a diagram showing an example in which the boundary between the liquid crystal alignment section A and the liquid crystal alignment section B is formed so as to overlap the gate bus line 32 of the active matrix circuit as described above.

The liquid crystals of the liquid crystal alignment sections A and B are both arranged so as to pretilt toward the gate bus lines 32 near the upper substrate 18 provided with the gate bus lines 32. That is, in FIG.
When viewed from the upper substrate 18, the molecules of the liquid crystal in the liquid crystal alignment section A are pretilt toward the gate bus line 32,
The liquid crystal molecules in the liquid crystal alignment section B are also pretilt toward the gate bus line 32.

FIG. 16 shows voltages applied to the common electrode 21, the drain bus line 30, and the gate bus line 32, respectively. The voltage of the drain bus line 30 corresponds to the voltage applied to the pixel electrode 24. The voltage of the gate bus line 32 is lower than the voltage of the common electrode 21 and the voltage of the drain bus line 30. Therefore, as shown in FIG.
2 and an electric field from the drain bus line 30 to the gate bus line 32 are formed. That is, near the gate bus line 32, the electric force lines are sucked into the gate bus line 32 from an oblique or horizontal direction. The liquid crystal 20 has a tendency to align along the line of electric force,
The pretilt of the liquid crystal in the liquid crystal alignment sections A and B near the gate bus line 32 is
, The alignment of the liquid crystal 20 at the boundary between the liquid crystal alignment section A and the liquid crystal alignment section B is improved.

FIG. 15 is a view showing a case where the same liquid crystal alignment sections A are arranged adjacent to each other, and the gate bus line 32 passes through the boundary of these liquid crystal alignment sections A. The liquid crystal in the left liquid crystal alignment section A is arranged to pretilt toward the gate bus line 32, while the liquid crystal in the right liquid crystal alignment section A is arranged to pretilt to the opposite side to the gate bus line 32. ing. In this case, the liquid crystal in the left liquid crystal alignment section A coincides with the electric lines of force directed to the gate bus line 32, while the liquid crystal in the right liquid crystal alignment section A intersects with the electric lines of force directed to the gate bus line 32. In the liquid crystal alignment section A on the right side, the molecules of the liquid crystal in the vicinity of the gate bus line 32 try to align along the lines of electric force toward the gate bus line 32, which is the alignment of most of the liquid crystal 20 in the liquid crystal alignment section A on the right side. It will be the opposite of the direction. That is, in this case, the alignment of the liquid crystal at the boundary between the two liquid crystal alignment sections A is disturbed.

FIG. 17 shows an embodiment of the present invention.
The liquid crystal display device of this embodiment has a common electrode 21 and an alignment film 22 provided on the inner surface of the lower substrate 16 and a plurality of pixel electrodes 24 provided on the inner surface of the upper substrate 18 as in the configuration of FIG. And an alignment film 26 and a liquid crystal 20 inserted between the substrates 16 and 18. The feature of the third embodiment is that the pixel electrodes 24 are formed such that the lines of electric force in oblique directions act on each of the pixel electrodes 24.

FIG. 17 is shown upside down from FIG. 3 to show the pixel electrode 24. In FIG. 17, the pixel electrode 24 is a divided pixel electrode 2 divided through a minute gap 46.
4a, and a horizontal electric field acts between these divided pixel electrodes 24a. Split pixel electrode 2
4a are each connected to the transistor 34 and are controlled separately. FIG. 18 shows a voltage of the drain bus line 30 similar to that of FIG. 16, and an AC voltage is supplied to the drain bus line 30 to drive the liquid crystal 20. The black part is the time when the gate opens.

FIG. 19 shows lines of electric force when applying voltages of the same polarity to the two divided pixel electrodes 24a. In this case, the lines of electric force are generally moved from the common electrode 21 to the divided pixel electrode 24.
It is formed in the direction toward a or the opposite direction,
In the vicinity of the gap between the two divided pixel electrodes 24a, the lines of electric force are oblique. As described above, the liquid crystal 20 has a tendency to be oriented along the line of electric force, and the orientation of the liquid crystal is determined by one of the divided pixel electrodes 24a with the gap 46 as a boundary.
And the direction toward the other divided pixel electrode 24a.

FIG. 20 shows lines of electric force when voltages of opposite polarities are applied to the two divided pixel electrodes 24a. In this case, the lines of electric force are generally directed from the common electrode 21 to one of the divided pixel electrodes 24a and the other divided pixel electrode 24a.
a, and in a direction from one divided pixel electrode 24a to the other divided pixel electrode 24a. Also in this case, the electric lines of force are in the oblique direction near the gap between the divided pixel electrodes 24a, and the alignment of the liquid crystal is
The direction toward one of the divided pixel electrodes 24a with
It is formed in the direction toward the other divided pixel electrode 24a.

Therefore, in any case, the lines of electric force are in the oblique direction near the gap 46 of the divided pixel electrode 24a, and the molecules of the liquid crystal pretilt in the opposite direction with the gap 46 as a boundary. This is because the liquid crystal 20 is divided into liquid crystal alignment sections A.
Even if it is not composed of the liquid crystal alignment section B and the liquid crystal alignment section B, the same effect as the improvement of the viewing angle characteristic can be obtained as in the case where the liquid crystal alignment section A and the liquid crystal alignment section B are provided. If the liquid crystal 20 is composed of the liquid crystal alignment sections A and B, and the boundary portion thereof is made to coincide with the gap 46 of the divided pixel electrode 24a, the alignment is further improved.

FIG. 21 is a diagram showing another example in which the lines of electric force are formed obliquely by the pixel electrodes 24. In FIG. In this case, a minute sub-pixel electrode 24c is provided on the pixel electrode 24 via an insulating layer 47, and the main pixel electrode 24 and the sub-pixel electrode 24c are provided.
The lines of electric force in the oblique direction act between them. Therefore, also in this case, the liquid crystal 20 is oriented in the opposite direction along the oblique line of electric force.

[0044]

As described above, according to the present invention,
The alignment of liquid crystal molecules is improved, and a liquid crystal display device having excellent contrast and viewing angle characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a liquid crystal display device.

FIG. 2 is a diagram showing two liquid crystal alignment sections.

FIG. 3 is a schematic sectional view of a liquid crystal display device.

FIG. 4 is a perspective view illustrating the behavior of a twisted nematic liquid crystal.

5A and 5B are diagrams showing one liquid crystal alignment section, FIG. 5A is a diagram showing an alignment state of liquid crystal molecules in each part, FIG. 5B is a simplified diagram of FIG. 5A, and FIG. It is YY 'sectional drawing of B).

FIG. 6 is a diagram showing two liquid crystal alignment sections.

FIG. 7 is a diagram illustrating viewing angle characteristics of a liquid crystal display device.

FIG. 8 is a diagram showing another arrangement of two liquid crystal alignment sections.

FIG. 9 is a diagram showing another arrangement of two liquid crystal alignment sections.

FIG. 10 is a diagram showing an active matrix circuit.

11A and 11B are diagrams illustrating a rubbing process, in which FIG. 11A illustrates a first rubbing, and FIG. 11B illustrates a second rubbing.

FIG. 12 is a plan view illustrating an example of a liquid crystal display device.

FIG. 13 is a sectional view of FIG.

FIG. 14 is a diagram illustrating the operation of FIG.

FIG. 15 is a diagram illustrating an operation of a configuration different from that of FIG. 12;

FIG. 16 is a diagram illustrating an example of voltage control.

FIG. 17 is a diagram showing an example of the present invention.

FIG. 18 is a diagram illustrating the voltage control of FIG. 17;

FIG. 19 is a view for explaining the operation of FIG. 17;

FIG. 20 is a view for explaining the operation of FIG. 17;

FIG. 21 is a diagram showing a modification of FIG. 17;

[Explanation of symbols]

 16, 18: substrate 20: liquid crystal 21, 24: electrode 22, 26: alignment film

Continued on the front page (72) Inventor Yoshiro Koike 1015 Uedanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Kenji Okamoto 1015 Kamiodanaka, Nakahara-ku, Nakazaki-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Invention Person Seiji Tanuma 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Yoshishiro Katayama 1015 Kamikodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (4)

[Claims] The first and second opposed substrates (16, 1
8) and a common electrode (2) provided on the inner surface of the first substrate.
1) and a first alignment film (22), a plurality of pixel electrodes (24) and a second alignment film (26) provided on the inner surface of the second substrate, and the first and second substrates And a liquid crystal (20) inserted between the pixel electrodes, wherein the pixel electrodes are formed such that oblique lines of electric force act on each of the pixel electrodes. Liquid crystal display device. 2. The method according to claim 1, wherein each of the pixel electrodes comprises a divided pixel electrode divided through a minute gap, and lines of electric force in oblique directions act between the divided pixel electrodes. The liquid crystal display device according to claim 1. 3. Each of the pixel electrodes comprises a main pixel electrode and a sub-pixel electrode having a smaller area than the main pixel electrode, and oblique lines of electric force act between the main pixel electrode and the sub-pixel electrode. The liquid crystal display device according to claim 1, wherein 4. The liquid crystal according to claim 1, wherein the liquid crystal comprises liquid crystal molecules in which liquid crystal molecules are pretilted and twisted in accordance with the alignment treatment of the first alignment film (22) and the second alignment film (26). 22) and the second alignment film (26)
Has first and second liquid crystal alignment sections (A, B) formed in each of a plurality of minute unit regions, having alignment directions substantially perpendicular to each other, and thus the first liquid crystal The alignment process is performed so that the major axis direction of the liquid crystal molecules in the alignment section and the major axis direction of the liquid crystal molecules in the second liquid crystal alignment section extend in a direction parallel to each other and pretilt in the opposite direction. 2. The liquid crystal display device according to claim 1, wherein the lateral electric field acts on the liquid crystal at the boundary between the first and second liquid crystal alignment sections (A, B).