JPH0643460A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To easily and surely execute an orientation processing whose oriented state of a liquid crystal is different at every minute area, and to stabilize a rise state of the liquid crystal. CONSTITUTION:The device is constituted so that it consists of a liquid crystal 20 inserted between a first and a second substrates, an oriented film 22 of a first substrate concerned and an oriented film 26 of a second substrate are divided into minute areas and subjected to orientation processing by setting a bus line 32 as a boundary so that an oriented state of the liquid crystal is different at every minute area, and as for a molecule of the liquid crystal for coming into contact with each of the oriented film 22 of a first substrate and the oriented film 26 of a second substrate in the minute area, the oriented direction is the same and the pretilt is different against a molecule of the liquid crystal for coming into contact with each of the oriented film 22 of a first substrate and the oriented film 26 of a second substrate in the adjacent minute area, and the liquid crystal rises toward the bus line 32 at the time when a voltage is applied.

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 in which the alignment state of liquid crystal is different for each minute region.

[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 transparent substrates facing each other. A common electrode and an alignment film are provided on the inner surface of one of the glass substrates,
A pixel electrode and an alignment film are provided on the inner surface of the other substrate. Recently, an active matrix circuit is often formed together with pixel electrodes on the latter substrate. Further, a polarizing plate is provided on the outside of each of these substrates. Usually, these polarizing plates are arranged such that the transmission axes of polarized light are orthogonal to each other. The following description will be made by taking the normally white mode as an example, but it goes without saying that technically similar ones are also applied to the normally black mode (parallel to the polarizing plate).

In a liquid crystal display panel, liquid crystal molecules are aligned and pretilt in accordance with the rubbing directions of the alignment films on both substrates. In a twisted nematic liquid crystal display device in which polarizing plates are arranged orthogonally, the rubbing directions of the alignment films on both substrates are substantially perpendicular to each other, and the liquid crystal molecules spiral from one substrate to the other. Twist.
Then, when no voltage is applied to the liquid crystal, the molecules of the liquid crystal maintain the initial twist and pretilt,
Incident light travels while turning along the twist of the liquid crystal and exits from the liquid crystal cell. At this time, white display is obtained in the normally white mode in which the polarizing plates are arranged orthogonally. When a voltage is applied, the liquid crystal rises, the birefringence action of the liquid crystal is weakened, the above-described light swirling action is weakened, and it becomes difficult for incident light to pass through the liquid crystal cell, resulting in black display. In this way, an image with bright and dark contrast as a whole is formed while controlling the voltage applied to the liquid crystal.

In the liquid crystal display device, the contrast of light and dark of the image changes depending on the direction in which the viewer looks at the screen. This is generally recognized as a viewing angle characteristic of a liquid crystal display device. For example, FIG. 7 is a diagram showing the viewing angle characteristics of a liquid crystal display device. An alternate long and short dash line C is a voltage-transmittance curve when the vertically arranged liquid crystal display device is viewed from the front. Dashed line L,
U is a voltage-transmittance curve when viewed from diagonally above and diagonally below at an angle of 40 degrees. In the case of the broken line L, since the decrease in the transmittance is small even if the voltage is increased, even if an attempt is made to obtain a black display, the display becomes relatively bright. Dashed line U
In this case, when a voltage is applied slightly, the transmittance is significantly reduced, and an image with a large contrast ratio can be obtained. This is called the good viewing angle direction and is indicated by a thick arrow in the following description. However, in the case of the broken line U, the transmittance increases again as the voltage increases, and the correspondence relationship between the voltage and the transmittance is reversed, which may be inconvenient for obtaining an intermediate color between white and black.

In order to solve the influence of such viewing angle characteristics, Japanese Patent Laid-Open No. 54-5754 and Japanese Patent Laid-Open No. 63-10 are recommended.
Japanese Patent No. 6624 proposes to form two regions having different alignment directions of liquid crystal molecules in one pixel. According to these proposals, it is possible to improve the visual characteristics as a whole by mixing an area having a certain visual angle characteristic and another area having a different visual angle characteristic.

FIG. 6 is a diagram showing an alignment treatment of such a conventional liquid crystal display device. FIG. 6 shows an area for one pixel, for example, which has two regions A and B in which the alignment states of liquid crystal molecules are different. Light enters one of the substrates (here, the substrate on the light incident side is called the lower substrate), passes through the liquid crystal, and exits from the other substrate (the upper substrate), and the viewer sees it from above the upper substrate. As an arrow, the rubbing direction of the alignment film on the lower substrate is indicated by an arrow 22a, and the rubbing direction of the alignment film on the upper substrate is indicated by an arrow 26a.

In the region A of FIG. 6, the rubbing direction 22a of the alignment film on the lower substrate is 45 degrees upward to the left, and the rubbing direction 26a of the alignment film on the upper substrate is 45 degrees to the left. The viewing angle characteristics in the case of such an alignment process are the same as those shown in FIG. 7, and the good viewing angle direction indicated by the thick arrow is the upper side in FIG. On the other hand, in the region B, the rubbing direction 22a of the alignment film on the lower substrate is 45 degrees to the right, and the rubbing direction 26a of the alignment film on the upper substrate is 45 degrees to the right. The viewing angle characteristics in the case of such an alignment treatment are upside down from those shown in FIG. 7, and the good viewing angle direction indicated by the thick line arrow is the lower side in FIG.

When the area A and the area B are arranged adjacent to each other, the characteristic indicated by the solid line I in FIG. 7 is obtained. The characteristics of the solid line I are those obtained by adding the characteristics of the broken line L and the broken line U and dividing by 2, and are close to the characteristics of the one-dot chain line C seen from the normal direction,
The viewing angle direction having extremely high transmittance and the viewing angle direction having extremely low transmittance are eliminated, and the viewing angle characteristics are improved. The area A and the area B are provided for each minute area that corresponds to the area of one pixel or several times or the reciprocal of the area of one pixel.

[0009]

However, in order to obtain a liquid crystal display device having a region A and a region B as shown in FIG. 6, the alignment film of each substrate is divided into small regions and rubbed. It is necessary to. For example, in FIG. 6, the rubbing directions 22a and 26a of the region A are opposite to the rubbing directions 22a and 26a of the adjacent region B.

In order to perform such rubbing, it has been considered to use a mask having openings corresponding to the minute regions A and B, and a resist is used as the mask. In this case, first, an alignment film is applied to the substrate, a resist is applied on the alignment film, and an opening corresponding to the area A (or B) is formed in the resist by photolithography, and the area A exposed from the resist is then formed. Rubbing is performed in a predetermined direction. Next, the resist is peeled off, another resist is applied on the alignment film, an opening corresponding to the region B is formed in the resist by photolithography, and the region B exposed from the resist is rubbed in a predetermined direction. To do. Next, the resist is peeled off.

Aligning the liquid crystal so that the alignment state is different for each minute region has a problem that many steps are required as described above. Further, conventionally, the portion that has been rubbed first may be disturbed by subsequent rubbing or etching, or may change over time, and the alignment performance of the liquid crystal may deteriorate. Further, in the active matrix drive liquid crystal display device, when the regions A and B are divided with the bus line as a boundary, a lateral electric field acts between the pixel electrode and the bus line (particularly, the gate bus line), and the liquid crystal The way of rising may be affected by this lateral electric field. Therefore, it has been desired to set the orientation of the liquid crystal so that the rising direction of the liquid crystal is stable and is affected by the lateral electric field.

An object of the present invention is to provide a liquid crystal display device capable of easily and surely performing an alignment treatment in which the alignment state of the liquid crystal is different for each minute region and stabilizing the rising of the liquid crystal. It is to be.

[0013]

In a liquid crystal display device according to the present invention, first and second substrates 16 and 18 facing each other, an electrode 21 and an alignment film 22 provided on the inner surface of the first substrate are provided.
And an electrode 24 and an alignment film 26 provided on the inner surface of the second substrate, and a liquid crystal 20 inserted between the first and second substrates. Differently from each other, the alignment film 22 of the first substrate and the alignment film 26 of the second substrate are divided into minute regions with the bus line 32 as a boundary, and the alignment treatment is performed. Each of the alignment film 22 of the first substrate and the alignment film 26 of the second substrate in a minute region where liquid crystal molecules are in contact with the alignment film 22 of the substrate and the alignment film 26 of the second substrate, respectively. The molecules are aligned in the same orientation as the molecules of the liquid crystal in contact with the pre-tilt, and the liquid crystal is connected to the bus line 3 when a voltage is applied.
It is characterized in that it is adapted to stand up toward 2.

[0014]

In the above structure, for example, one of the substrates is oriented so that the first pretilt is obtained in a certain minute area and the second pretilt is different in the adjacent minute area. It In this case, the rubbing directions of the certain minute area and the adjacent minute area may be the same. On the other board,
The alignment treatment is performed in advance so that the second pretilt is obtained in the minute area facing the certain minute area and the first pretilt is obtained in the minute area facing the adjacent minute area. Also in this case, the rubbing directions of both minute regions may be the same. Therefore, in both substrates, the first pretilt region and the second pretilt region face each other and are alternately adjacent to each other. Thereby, it is possible to form a liquid crystal display device having two minute regions in which the alignment state of the liquid crystal is different for both substrates by one rubbing treatment step. Then, these minute regions are divided with the bus line as a boundary, and the liquid crystal rises toward the bus line when a voltage is applied.
Therefore, the liquid crystal is affected by the lateral electric field between the pixel electrode and the bus line, and is arranged along the line of electric force, so that the rising manner of the liquid crystal is stabilized.

Further, according to the present invention, the first substrate in the minute region in which the liquid crystal molecules are in contact with each of the alignment film 22 of the first substrate and the alignment film 26 of the second substrate in the minute region. Alignment film 22 and the alignment film 2 of the second substrate
The liquid crystal molecules in contact with each of 6 have the same orientation direction but different pretilts, and the difference in pretilt between adjacent regions is 2 degrees or more. As a result, the alignment state can be well controlled by the difference in pretilt.

[0016]

1 is a view showing a liquid crystal panel 10 of a liquid crystal display device according to an embodiment of the present invention. Polarizing plates (not shown) are arranged on both sides of the liquid crystal panel 10 in a vertical relationship in the normally white mode or in a parallel relationship in the normally black mode. The liquid crystal panel 10 is
A liquid crystal 20 is enclosed between a pair of transparent glass substrates 16 and 18. The liquid crystal 20 is a twisted nematic liquid crystal. Light from a light source (not shown) enters the liquid crystal panel 10 from the direction of the arrow L, and the viewer views the liquid crystal panel 10 from the direction opposite to the incident direction. The substrate 16 is called a lower substrate,
The board 18 on the viewer side will be referred to as an upper board.

The color filter layer 1 is formed on the inner surface of the lower substrate 16.
9, the ITO common electrode 21 and the alignment film 22 are provided,
A pixel electrode 24 and an alignment film 26 are provided on the inner surface of the upper substrate 18. The pixel electrode 24 provided on the upper substrate 18 is connected to the active matrix circuit. As shown in FIG. 3, the active matrix circuit includes data bus lines 30 and gate bus lines 32 extending vertically and horizontally in a matrix, and the pixel electrode 24 is a thin film transistor (TF).
T) 34, and is connected to the data bus line 30 and the gate bus line 32. FIG. 4 shows the color filter layer 19 of the lower substrate 16, which is a black matrix having color filters (R, G, B) 19a provided corresponding to the pixel electrodes 24 and openings corresponding to the color filters 19a. And 19b. FIG. 3 is a view seen through the pixel electrode 24 and the like from the upper surface side of the upper substrate 18, and when the upper substrate 18 of FIG.
This shows that the pixel electrode 24 and the color filters (R, G, B) 19a have a positional relationship of overlapping.

As shown in FIG. 1, the alignment film 22 of the lower substrate 16 and the alignment film 26 of the upper substrate 18 are subjected to alignment treatment so that the alignment state of the liquid crystal 20 is different for each minute region. More specifically, the alignment film 22 of the lower substrate 16 and the alignment film 26 of the upper substrate 18 are each made up of a lower-layer-side alignment material layer 51 and an upper-layer-side alignment material layer 53, which are provided in layers. The alignment material layer 53 is patterned so as to have an opening corresponding to one minute region. Then, the alignment layer 53 on the upper layer side and the alignment layer 51 on the lower layer side are simultaneously rubbed, so that the liquid crystal in contact with each of the alignment film 22 of the lower substrate 16 and the alignment film 26 of the upper substrate 18 in a certain minute region. The alignment direction is the same as the molecules of the liquid crystal in contact with the alignment film 22 of the lower substrate 16 and the alignment film 26 of the upper substrate 18 in the minute regions where the molecules are adjacent to each other, but the pretilt is different.

In FIG. 1, an alignment material layer 53 on the upper side of the alignment film 26 of the upper substrate 18 and a lower alignment material layer 51 exposed from the alignment material layer 53 on the upper side of the alignment film 22 of the lower substrate 16 are shown. Thus, a minute area A is formed. The alignment material layer 53 on the upper layer side of the alignment film 26 of the upper substrate 18 is adjacent to the minute region A.
A small region B is formed by the lower-layer-side alignment material layer 51 exposed from the above and the upper-layer-side alignment material layer 53 of the alignment film 22 of the lower substrate 16.

FIG. 1 shows the liquid crystal 20 in the minute regions A and B.
It is shown that the molecules are twisting, and
The child is circled at the end visible on the front side with respect to the plane of Fig. 1.
It is shown with. In the small area A, the lower group
Liquid contacting the alignment material layer 51 on the lower side of the alignment film 22 of the plate 16
The crystal molecules are oriented from the far right to the far left.
And angle α₂It is pretilt with. Liquid in the middle part
The crystal molecules are oriented in a direction substantially parallel to the plane of FIG.
And the alignment material on the upper layer side of the alignment film 26 of the upper substrate 18.
The liquid crystal molecules in contact with the layer 53 move from the left back to the front right
Orientation direction and angle α₁Pre-tilt with
There is. In this case, the angle α₁Is the angle α ₂Greater than
Yes. The present invention uses α₁And α₂Even if the size relationship of
The same effect is produced.

On the other hand, in the minute area B, the lower substrate 1
The liquid crystal molecules in contact with the alignment material layer 53 on the upper layer side of the alignment film 22 of _{No. 6} have an alignment direction from the right back to the left front, and are pretilted at an angle α ₁ . The liquid crystal molecules in the middle portion have an alignment direction substantially parallel to the plane of FIG. 1, and the liquid crystal molecules in contact with the alignment material layer 51 on the lower layer side of the alignment film 26 of the upper substrate 18 are from the left back to the right. It is oriented in the forward direction and is pretilted at an angle α ₂ . Also in this case, the angle α ₁ is larger than the angle α ₂ .

Looking at this for the alignment film 26 of the upper substrate 18, for example, the liquid crystal molecules in contact with the alignment material layer 53 on the upper side of the alignment film 26 in the minute region A are aligned in the alignment direction from the left back to the front right. And pretilt at an angle α ₁ . The molecules of the liquid crystal in contact with the alignment material layer 53 on the upper layer side of the alignment film 26 in the minute region B have an alignment direction from the left back to the front right and are pretilted at an angle α ₂ . That is, in the upper substrate 18, the liquid crystal molecules in contact with the alignment film 26 of the upper substrate 18 in the minute regions A and B both have an alignment direction from the left back to the front right, but the pretilt angle is α ₁ . It differs from α ₂ . This relationship also applies to the alignment film 22 on the lower substrate 16.

FIG. 2 is a diagram showing a process of forming the alignment film 26 of the upper substrate 18 including the alignment material layer 51 on the lower layer side and the alignment material layer 53 on the upper layer side. The alignment film 22 of the lower substrate 16 can be formed by the same process. As shown in (A), the upper substrate 1
Then, the alignment material layer 51 on the lower layer side and the alignment material layer 53 on the upper layer side are entirely applied from above the pixel electrode 24 of No. 8 and the gate bus line 30. The lower orientation material layer 51 is made of, for example, an inorganic orientation material such as SiO ₂ / TiO ₂ , and the upper orientation material layer 53 is made of an organic orientation material such as polyimide having an imidization ratio of 100%. The film thickness of the lower orientation material layer 51 and the upper orientation material layer 53 may be about 500A. Next, as shown in (B), the alignment material layer 53 on the upper layer side is patterned by etching using the resist 55 as a mask. A commercially available positive photoresist is used as the resist 55, and an alkaline etching solution is used. In reality, the upper alignment layer 53 is etched by the developing solution during the resist development. The orientation material layer 53 on the upper layer side of the polyimide is easily dissolved in the alkaline etching solution, but the orientation material layer 51 on the lower layer side is not dissolved in the etching solution.

Then, after removing the resist 55,
As shown in (C), the lower alignment material layer 51 and the upper alignment material layer 53 are rubbed simultaneously. The rubbing is performed by advancing the rubbing roller 57 wound with a rubbing material such as fiber on the alignment film 26 of the upper substrate 16 while rotating in the direction of the arrow.

Therefore, the upper alignment material layer 53 and the lower alignment material layer 51 exposed from the upper alignment material layer 53 are rubbed in the same direction. However, the pretilt angle differs depending on whether the molecules of the liquid crystal are in contact with the upper alignment material layer 53 or the lower alignment material layer 51. In the test, the liquid crystal molecules in contact with the upper alignment material layer 53 have a pretilt angle of about 4 degrees (α ₁ ), and the liquid crystal molecules in contact with the lower alignment material layer 51 have an angle of about 4 degrees (α ₁ ). It was confirmed that pretilt was performed up to about 1 degree (α ₂ ). Further, in the above description, the upper orientation material layer 53 is patterned by etching, but the upper orientation material layer 53 may be formed by printing or the like. Further, the pretilt may be changed by some method (for example, by partially irradiating ultraviolet rays) even if the alignment film is not composed of two layers. In addition, transparent electrodes (pixel electrode and common electrode)
Can be used as the lower layer alignment film, and polyimide can be applied as the upper layer alignment film, followed by patterning and rubbing.

FIG. 5 shows a simplified orientation state of such minute regions A and B. In the minute region A of FIG. 5, the orientation direction of the alignment material layer 53 on the upper layer side of the alignment film 22 of the upper substrate 18 is shown by a dashed arrow 26a, and as can be seen from the above description, this upper substrate 18 side. The liquid crystal molecules of ₁ pretilt at a large angle α ₁ . In the minute region B, the alignment direction of the alignment material layer 53 on the upper layer side of the alignment film 22 of the lower substrate 16 is indicated by a solid arrow 22a, and the liquid crystal molecules on the lower substrate 16 side have a large angle. α
Pretilt with ₁ .

Thus, in the minute areas A and B,
One of the substrates 16 (1
In the case of pretilting at a large angle α ₁ on the side 8) and pretilting at a small angle α ₂ on the other substrate 18 (16) side, when a voltage is applied, the molecules of the liquid crystal in the middle part are indicated by arrows in FIG. As shown, it rises in the direction in which the pretilt angle is large. Therefore, in the minute area A of FIG. 5, the rising of the liquid crystal follows the alignment treatment of the upper substrate 18 indicated by the broken arrow 26a. In the minute area B, the rising of the liquid crystal is indicated by the solid arrow 22.
It follows the alignment treatment of the lower substrate 16 indicated by a.

Therefore, the rising of the liquid crystal in the minute area A in FIG. 5 is the same as that in the area A shown in FIG. This is because the rising of the liquid crystal in FIG. 6 also follows the dashed arrow 26a. Similarly, the rising of the liquid crystal in the minute region B in FIG. 5 is the same as that in the liquid crystal alignment region B shown in FIG. However, the arrow 22a indicating the rubbing direction on the lower substrate 16 side of the minute region A in FIG. 5 is opposite to the arrow 22a indicating the rubbing direction on the lower substrate 16 side of the region A in FIG. Therefore, the molecules of the liquid crystal shown in FIG. 5 are aligned parallel to the molecules of the liquid crystal shown in FIG. 6, and the pretilt directions are opposite. Therefore, the liquid crystal molecules in the minute area A of FIG.
Twisting is performed in the same manner as the liquid crystal molecules in the area A. The same applies to the minute region B.

However, since the pretilt of the liquid crystal molecules in contact with the alignment film 26 of the upper substrate 18 is opposite to the pretilt of the liquid crystal molecules in contact with the alignment film 22 of the lower substrate 16, the pretilt angle of the liquid crystal is changed by applying a voltage. The behavior of the molecules of the liquid crystal having a small pretilt angle in the opposite direction is considered to be unstable when rising to the larger side. Nevertheless, it was confirmed that the liquid crystal display device according to the present invention can form a much clearer image than the liquid crystal display device formed as shown in FIG. The reason is that, in the present invention, as described with reference to FIG. 2, the rubbing process step only needs to be performed once near the end of the alignment process to form a plurality of alignment states. . The lower substrate 16 and the lower substrate 18 are assembled in a so-called hot state without taking time from this rubbing operation and without passing through another processing process, and immediately the liquid crystal 2
It is considered that since 0 can be injected, the liquid crystal 20 can be sealed in a state where there is no change over time in the rubbing process. That is, according to the present invention, the rubbing process is not disturbed, and the rubbing effect is improved, as compared with the case where exposure and etching are performed after the first rubbing and then the second rubbing is performed as in the conventional case. Seems to be stable.

Further, for example, in the minute area A of FIG.
The rise of the liquid crystal mainly follows the alignment treatment on the upper substrate 18 side, and the effect of the alignment treatment on the lower substrate 16 side seems to be secondary. In that case, the lower substrate 1
There may be a question that it may not be necessary to perform orientation processing on the 6 side. However, if only one substrate is oriented and the other substrate is not oriented, the liquid crystal will twist exactly 90 degrees unless the relationship between the material of the liquid crystal and the thickness of the liquid crystal layer is specified very strictly. do not become. In the present invention, for example, the rubbing direction 22a of the minute area A in FIG.
Since it is parallel to a, the alignment treatment on the lower substrate 16 side, in association with the alignment treatment on the upper substrate 18 side, helps at least the liquid crystal twist at exactly 90 degrees.

Further, in the present invention, the setting of the alignment state is
When a voltage is applied, the liquid crystal 20 rises toward the gate bus line 32, for example. 3 and 4 are diagrams showing setting examples of minute regions A and B having different alignment states of liquid crystal. Pixel electrode 24 and color filter (R, G, B)
19a is shown in an overlapping positional relationship. Pixel electrode 2
4, the pixel electrode 24 is provided in each section of the data bus line 30 and the gate bus line 32. In such a structure, the minute regions A and B in which the alignment state of the liquid crystal is different are
Pixel electrode 24 (and color filter (R, G, B) 19
The gate bus line 32 and the line passing through the center of a) are divided as boundaries. In addition, the minute areas A and B are
It is also possible to divide the pixel electrode 24 with a line passing through substantially the center thereof and the data bus line 30 as boundaries.

FIG. 1A corresponds to, for example, a sectional view seen from the left side along a line parallel to the data bus line 30 of FIG. 3, and a gate bus line 32 passes between two pixel electrodes 24. It shows the part. FIG. 1B is a schematic diagram showing the vicinity of the pixel electrode 24, and the alignment films 22 and 26 are omitted. In FIG. 1A, in the minute area A, the alignment material layer 53 on the upper layer side of the alignment film 26 of the upper substrate 18 is formed.
The molecules of the liquid crystal in the vicinity of are raised toward the gate bus line 32 when a voltage is applied.

As shown in FIG. 8, an alternating voltage of ± 5 volts is applied to the data bus line 30 as indicated by V ₃₀ , and a gate bus line 32 is -15 volts as indicated by V _32. A pulsed gate voltage is applied to the base voltage of the. Therefore, as shown in FIG. 1B, a lateral electric field acts between the pixel electrode 24 and the gate bus line 32 to form an electric force line E. Of course,
An electric field acts between the pixel electrode 24 and the common electrode 21,
The liquid crystal 20 basically rises due to this electric field.

Since molecules of twisted nematic liquid crystal have a property of rising in the direction of an electric field, they are affected by a lateral electric field. The rubbing direction of the alignment film 26 of the upper substrate 18 in the above-described minute region A causes a pretilt (α ₁ ) such that liquid crystal molecules rise toward the gate bus line 32. The inclination of the molecule is almost the same as the inclination of the electric force line E of the transverse electric field passing through the position. As described above, the present invention has an advantage that the rise of the liquid crystal according to the alignment state and the rise of the liquid crystal according to the lateral electric field are the same, so that the rise of the liquid crystal is stable. On the other hand, if region A
When the rubbing direction of the alignment film 26 of the upper substrate 18 is opposite to that described above (that is, the rubbing direction indicated by the arrow in FIG. 3 is reversed), the pretilt direction of the liquid crystal is opposite to that in FIG. In FIG. 1, the liquid crystal molecules come to the lower left, and the liquid crystal molecules start to rise with their backs facing the gate bus lines 32. Then, there is a possibility that the way the liquid crystal rises when a voltage is applied becomes unstable.

FIG. 9 is a diagram showing the contrast ratio with respect to the viewing angle in the normally white mode. The curve plotting the circle points is the contrast ratio of the conventional liquid crystal display device having a uniform orientation, and the curve plotting the cross points is the liquid crystal display device in which the alignment state of the liquid crystal is made different for each minute region according to the present invention. Is the contrast ratio of. According to the present invention, the contrast ratio can be improved over a wide viewing angle. The portion on the right side of the curve in which the circle points are plotted has a high contrast ratio, but this portion includes the portion where the light and dark are inverted as described with reference to FIG. 7.

FIG. 10 is a diagram showing the contrast ratio when used in the normally black mode. Similarly, a plot curve of circle dots is a contrast ratio of a conventional liquid crystal display device having a uniform alignment, and a plot curve of cross points is a liquid crystal display in which the alignment state of the liquid crystal is made different for each minute region according to the present invention. The contrast ratio of the device. According to the present invention, the contrast ratio can be improved over a wide viewing angle.

FIG. 11 is a diagram showing the contrast ratio when used in the normally black mode. Alignment material layer 5 on the lower layer side.
1 is rubbed in the same direction. However, the pretilt angle differs depending on whether the molecules of the liquid crystal are in contact with the upper alignment material layer 53 or the lower alignment material layer 51. In the test, the liquid crystal molecules in contact with the upper alignment material layer 53 have a pretilt angle of about 4 degrees (α ₁ ), and the liquid crystal molecules in contact with the lower alignment material layer 51 have an angle of about 4 degrees (α ₁ ). Pre-tilt to about 1 degree (α ₂ )

As described above, according to the present invention, one substrate 18
Or 16 in the area A and the area B adjacent to the area A
And the pretilt (α ₁ , α ₂ ) are different from each other in the same alignment direction, so that in the same region A or B, the alignment film 26 of the upper substrate 18 and the alignment film 22 of the lower substrate 16 facing each other are formed. The contacting liquid crystal 20 is oriented with different pretilts (α ₁ , α ₂ ), and the rising of the liquid crystal 20 when a voltage is applied is controlled to the pretilt (α ₁ ) having a large angle.

Therefore, in the present invention, a combination of different pretilts α ₁ and α ₂ was further investigated. FIG. 11 is a diagram showing the results of evaluation of alignment by producing liquid crystal panels having various combinations of different pretilts α ₁ and α ₂ . As can be seen from FIG. 11, if the difference between the different pretilts (α ₁ , α ₂ ) of the adjacent regions A and B is 2 degrees or more, a good alignment state of liquid crystal can be obtained. Note that this result is applicable not only to the alignment state in which the liquid crystal rises toward the gate bus line 32, but also to the opposite state.

[0040]

As described above, according to the present invention,
It is possible to easily and surely perform the alignment treatment in which the alignment state of the liquid crystal is different for each minute region, to stabilize the rising direction of the liquid crystal, and to obtain the liquid crystal display device having excellent viewing angle characteristics and contrast.

[Brief description of drawings]

1A and 1B are diagrams showing an embodiment of the present invention, in which FIG. 1A is a sectional view of a liquid crystal panel, and FIG.

2A and 2B are diagrams showing the alignment treatment of FIG. 1, in which FIG. 2A shows formation of two alignment material layers, FIG. 2B shows patterning of the upper alignment material layer, and FIG. C) is a diagram showing a rubbing process.

FIG. 3 is a diagram showing an example of an alignment treatment of an upper substrate.

FIG. 4 is a diagram showing an example of an alignment treatment of a lower substrate.

FIG. 5 is a diagram simply showing the alignment treatment of FIG.

FIG. 6 is a diagram simply showing a conventional alignment treatment.

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

FIG. 8 is a diagram showing a voltage of a bus line.

FIG. 9 is a diagram showing a contrast ratio in a normally white mode.

FIG. 10 is a diagram showing a contrast ratio in a normally black mode.

FIG. 11 is a diagram showing evaluation of orientation by pretilt.

[Explanation of symbols]

 16, 18 ... Substrate 20 ... Liquid crystal 21, 24 ... Electrodes 22, 26 ... Alignment film 32 ... Gate bus line

Claims (3)

[Claims] 1. A first and a second opposing substrate (16, 1).
8) and an electrode (21) provided on the inner surface of the first substrate
An alignment film (22), an electrode (24) and an alignment film (26) provided on the inner surface of the second substrate, and the first and second alignment films.
Liquid crystal (20) inserted between the substrates, and the alignment film (22) of the first substrate and the alignment film of the second substrate ( 26) is subjected to an alignment treatment by dividing it into minute regions with the bus line (32) as a boundary, and the alignment film (22) of the first substrate and the alignment film (26) of the second substrate in the minute regions. Of the liquid crystal molecules in contact with the alignment film (22) of the first substrate and the alignment film (26) of the second substrate in the minute regions where the liquid crystal molecules are in the same alignment direction. A liquid crystal display device characterized in that the pretilts are made different so that the liquid crystal rises toward the bus line (32) when a voltage is applied. 2. An alignment material layer (51) on the lower layer side and an alignment layer on the upper layer side, each of which is provided with an alignment film (22) of the first substrate and an alignment film (26) of the second substrate laminated on each other. Timber layer (5
3) and the upper orientation material layer (53) is patterned so as to open according to the minute regions, and the upper orientation material layer (53) and the lower orientation material layer (53) are formed. 5
1) is rubbed at the same time, and the alignment material layer (5
3) and the liquid crystal in contact with the lower alignment material layer (51) are pre-tilted at different angles, and the higher pre-tilt of the liquid crystal in the part rises toward the bus line (32). The liquid crystal display device according to claim 1. 3. A first and a second opposing substrate (16, 1).
8) and an electrode (21) provided on the inner surface of the first substrate
An alignment film (22), an electrode (24) and an alignment film (26) provided on the inner surface of the second substrate, and the first and second alignment films.
Liquid crystal (20) inserted between the substrates, and the alignment film (22) of the first substrate and the alignment film of the second substrate ( 26) is subjected to alignment treatment by dividing it into minute regions, and liquid crystal molecules in contact with each of the alignment film (22) of the first substrate and the alignment film (26) of the second substrate in the minute regions are The alignment film (22) of the first substrate and the alignment film (26) of the second substrate in the adjacent minute regions have the same alignment direction as the molecules of the liquid crystal and have different pretilts, and are adjacent to each other. A liquid crystal display device, wherein a difference in pretilt in different regions is about 2 degrees or more.