JP2806673B2 - Liquid crystal display device and method of manufacturing the same - Google Patents

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 area.

[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. Hereinafter, the normally white mode will be described as an example. However, it is needless to say that a technically similar mode is also applied to a normally black mode (parallel polarizing plate).

[0003] Twisted nematic liquid crystals are often used in liquid crystal display panels. The liquid crystal molecules are aligned and pretilt according to the rubbing directions of the alignment films on both substrates. In other words, the major axis direction of the liquid crystal molecules extends parallel to the rubbing direction of the alignment film of the substrates, and the rubbing directions of the alignment films of both substrates are substantially perpendicular to each other. Spirally toward the substrate. Further, the alignment of the liquid crystal can be controlled by, for example, forming an alignment film by oblique evaporation.

When no voltage is applied to the liquid crystal, the molecules of the liquid crystal maintain the initial twist and pretilt, and the incident light travels while rotating along the twist of the liquid crystal and exits from the liquid crystal cell. At this time, a white display is obtained in the normally white mode. When voltage is applied,
When the liquid crystal rises, the birefringence effect of the liquid crystal is weakened, and the above-described swirling action of the light is weakened, so that the incident light is hardly transmitted 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 with a pretilt gradient. 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,
Due to the anisotropy of the refractive index, the effect of birefringence differs between the case where polarized light is incident parallel to the major axis and the case where polarized light is incident perpendicularly. 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 by applying a voltage, a viewer differs in the positional relationship with the major axis direction of the liquid crystal molecules depending on the viewing direction of the screen, and the light transmittance is reduced. The degree of black display obtained due to the difference is different. 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 proposes that the twist direction of liquid crystal molecules be different for each minute region of liquid crystal. JP-A-63-106624 discloses 1
It has been proposed to form two liquid crystal alignment regions having different alignment directions of liquid crystal molecules in a pixel. According to these proposals, the overall visual characteristics can be improved by mixing a liquid crystal alignment region having a certain viewing angle characteristic and another liquid crystal alignment region having a different viewing angle characteristic.

FIG. 6 shows an alignment process of such a conventional liquid crystal display device, in which alignment states of liquid crystal molecules are different.
It has two liquid crystal alignment regions A and B. FIG. 8 shows the characteristics of one of the liquid crystal alignment regions A. FIG. 8 shows that the liquid crystal 20 is inserted between the lower alignment film 22 and the upper alignment film 26 (C), and light enters from the lower alignment film 22 and passes through the liquid crystal to form an upper alignment film. The case where the light is emitted to the upper alignment film 26 is seen from the upper alignment film 26. 8A to 8C, reference numeral 20L denotes a liquid crystal molecule located near the lower alignment film 22, and reference numeral 20C denotes a lower alignment film 22.
And UU indicate liquid crystal molecules located in an intermediate portion (center of the liquid crystal layer) between the upper alignment film 26 and 20U. FIG. 8 shows an example in which the liquid crystal is oriented so as to twist counterclockwise. As shown in FIG. 8B, the lower alignment film 22 is rubbed in a rubbing direction 22a indicated by a solid arrow. Then, the upper alignment film 26 is rubbed in the rubbing direction 26a indicated by the dashed arrow.

FIG. 8A shows a liquid crystal molecule (lower molecule) 20L near the lower alignment film 22, a liquid crystal molecule (intermediate molecule) 20C in the middle portion, and a liquid crystal molecule near the upper alignment film 26. (Upper molecule) FIG. The left half of FIG. 8A shows these liquid crystal molecules 20L and 20L.
C, a plan view of 20U viewed from the surface of the upper substrate,
The right half is the liquid crystal molecules 20L, 20C, 20U.
Is a cross-sectional view as viewed with the 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. 8A, the lower molecule 20L of the liquid crystal extends in the direction of 45 degrees from the lower right to the upper left in the plan view similarly to the rubbing arrow 22a in FIG. Indicates a pretilt that rises with respect to the lower alignment film 22. The intermediate molecules 20C of the liquid crystal extend vertically from bottom to top in the plan view, and the cross-sectional view shows a pretilt in which the left end rises. The upper molecule 20U of the liquid crystal extends in the direction of 45 degrees from the lower left to the upper right in the plan view, and the cross section shows a pretilt in which the right end rises with respect to the upper alignment film 26.

Attention is paid to the intermediate molecules 20C of the liquid crystal located at the intermediate portion between the lower alignment film 22 and the upper alignment film 26. When the voltage is not applied, the intermediate molecules 20C of the liquid crystal are lower than those of the upper and lower liquid crystals. Like the molecules 20U and 20L, they are oriented almost horizontally, but when a voltage is applied, they rise up to a certain inclination angle as shown by a broken line. (C) in FIG. 8 shows the relationship between medium molecular 20C and viewing angle direction of the liquid crystal, an arrow E _C represents the view the liquid crystal panel from the normal direction, an arrow E _L, E _U looks downward and from above, respectively Shows the case.

[0012] 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, will see a dark black display when a voltage is applied. Conversely, looking at it from the direction of arrow E _L, liquid crystal intermediate molecules 2
The magnitude of the birefringence of 0C shows a relatively large value. In this case, since the amount of transmitted light is large, a brighter black display is seen. Thus, in the case of one 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 region A is shown by a dashed line C and broken lines L and U in FIG. The dashed line C in FIG. 9 is a voltage / transmittance curve when viewed from the front. Dashed lines L and U are voltage / transmittance curves when viewed from obliquely above and below obliquely 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, when a small voltage is applied, the transmittance is greatly reduced, and an image having a large contrast ratio is obtained.
This is called a good viewing angle direction, and is indicated by a thick arrow in FIG. In other figures, such a good viewing angle direction is indicated by a thick arrow. However, in the case of the broken line U, if the voltage further increases, the transmittance increases again, and the correspondence between the voltage and the transmittance reverses, which may be inconvenient in obtaining an intermediate color between white and black.

For this reason, as shown in FIG. 6, a liquid crystal alignment region B having characteristics complementary to the liquid crystal alignment region A is provided.
The liquid crystal alignment region A and the liquid crystal alignment region B are arranged adjacent to each other. The rubbing directions 22a, 26a of the alignment films 22, 26 in the liquid crystal alignment region B are perpendicular to each other, and the rubbing directions 22a, 26 of the alignment films 22, 26 in the liquid crystal alignment region A are mutually perpendicular.
a is opposite to each other. Therefore, the rise of the intermediate molecules 20C in the liquid crystal alignment region B when voltage is applied is opposite to that in the case of the liquid crystal alignment region A. Therefore, the viewing angle characteristics of the liquid crystal alignment region B are, as opposed to the liquid crystal alignment region A, bright when viewed from above and dark when viewed from below. That is, the good viewing angle direction is downward.

When the liquid crystal alignment region A and the liquid crystal alignment region B are arranged adjacent to each other, the characteristic shown by the solid line I in FIG. 9 is obtained. The characteristic of the solid line I is obtained by adding the characteristics of the dashed line L and the dashed line U and dividing by two, and is close to the characteristic of the one-dot chain line C viewed from the normal direction. There is no viewing angle direction with a low rate, and the viewing angle characteristics are improved. The liquid crystal alignment region A and the liquid crystal alignment region B are provided for each minute region corresponding to the area of one pixel, or several times or reciprocal times the area of one pixel.

[0016]

However, in order to obtain such a liquid crystal display device, it is necessary to rub the alignment film on one substrate by dividing it into small regions each corresponding to, for example, one pixel region. is required. For example, with respect to the lower alignment film 22 in FIG. 6, in the liquid crystal alignment region A, rubbing is performed in the rubbing direction 22a, and the adjacent liquid crystal alignment region B
Then, it is necessary to perform rubbing in the rubbing direction 22a opposite to the former. Similarly, for the upper alignment film,
It is necessary to perform rubbing in the opposite direction between the liquid crystal alignment region A and the liquid crystal alignment region B.

In order to perform such rubbing, it has been considered to perform rubbing using a mask having openings corresponding to minute liquid crystal alignment regions A and B, and a resist is used as a 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 liquid crystal alignment region A (or B) is provided in the resist by photolithography. Rubbing is performed on the alignment region A in a predetermined direction. Next, the resist is peeled off, another resist is applied on the alignment film, and an opening corresponding to the liquid crystal alignment region B is provided in the resist by photolithography. Rub in the direction. Next, the resist is stripped.

As described above, there is a problem that performing the alignment treatment so that the alignment state of the liquid crystal is different for each minute region requires many steps as described above. Conventionally, the rubbed portion may be disturbed by a series of subsequent photolithography steps (resist coating, exposure, development, and peeling) or may change with time, and the liquid crystal alignment performance may deteriorate. there were. SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device capable of easily and reliably performing an alignment process in which the alignment state of liquid crystal is different for each minute region.

[0019]

A liquid crystal display device according to the present invention comprises first and second opposed substrates 16 and 18, electrodes 21 and an alignment film 22 provided on the inner surface of the first substrate.
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. Second
The alignment film 22 of the first substrate and the alignment film 26 of the second substrate are separately subjected to an alignment process so as to include the minute regions A and B, and a liquid crystal in contact with the alignment film 22 of the first substrate. Have the same pre-tilt direction in the first and second minute regions A and B and have different pretilts, and the molecules of the liquid crystal in contact with the alignment film 26 of the second substrate are the first and second micro regions. Have the same pre-tilt and the same orientation in the micro regions A and B, and have the first and second micro regions A and B facing each other with the alignment films 22 and 22 of the first substrate. The pretilt of liquid crystal molecules in contact with the alignment film 26 of the second substrate is different from each other. Further, the method for manufacturing a liquid crystal display device according to the present invention,
First and second opposed substrates 16 and 18, an electrode 21 and an alignment film 22 provided on the inner surface of the first substrate, 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, wherein the lower layers are stacked as alignment films 22 and 26 of the first and second substrates. After forming the upper side alignment agent layer 53 and the upper side alignment agent layer 53 so that the lower side alignment agent layer 51 is exposed, the upper side alignment agent layer 53 is selectively opened. Upper alignment layer 5
3 and the lower alignment agent layer 51 are simultaneously rubbed so that the pretilt of liquid crystal molecules in contact with the upper alignment agent layer 53 and the lower alignment agent layer 51 is different from each other. Features. Further, the method for manufacturing a liquid crystal display device according to the present invention includes the first and second opposed substrates 16 and 18, an electrode 21 and an alignment film 22 provided on an inner surface of the first substrate, A method for manufacturing a liquid crystal display device comprising an electrode 24 and an alignment film 26 provided on an inner surface of a substrate, and a liquid crystal 20 inserted between the first and second substrates, the method comprising: Substrate alignment film 22,
Against each of 26, partitioned minute area including the display unit
By selectively irradiating A and B with ultraviolet rays, the first
In addition, the pretilt of the molecules of the liquid crystal in contact with each of the alignment films 22 and 26 of the second substrate is different from each other in the ultraviolet irradiation region and the non-irradiation region.

[0020]

In the above structure, the liquid crystal molecules in contact with each of the alignment film 22 of the first substrate and the alignment film 26 of the second first substrate in a minute region are adjacent to each other in the minute region where the molecules of the liquid crystal are adjacent to each other. The liquid crystal molecules in contact with each of the alignment film 22 of the first substrate and the alignment film 26 of the second first substrate have the same alignment direction and different pretilt. For example,
One substrate is subjected to an alignment process so that a first pretilt is obtained in a certain minute area and a different second pretilt is obtained in an adjacent minute area. In this case, the rubbing directions of the certain minute area and the adjacent minute area may be the same. In the other substrate, a second pretilt is obtained in a minute region facing the certain minute region, and a first pretilt is obtained in a minute region facing the adjacent minute region. Orientation treatment. Also in this case, the rubbing directions of the two minute regions may be the same. Thus, in both substrates, a liquid crystal display device having two minute regions having different alignment states of liquid crystal can be formed in one rubbing process.

[0021]

1 and 2 show an embodiment of the present invention. FIG. 1 shows a liquid crystal panel 10 of a liquid crystal display device according to an embodiment of the present invention. Polarizing plates (not shown) are provided on both sides of the liquid crystal panel 10 in a vertical relationship when in a normally white mode, or in a normal state. They are arranged in a parallel relationship in the mariblack mode. The liquid crystal panel 10 has a liquid crystal 20 sealed between a pair of transparent glass substrates 16 and 18. The liquid crystal 20 uses 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 E views the liquid crystal panel 10 from the direction opposite to the incident direction. The substrate 16 is referred to as a lower substrate, and the substrate 18 on the viewer side is referred to as an upper substrate.

The color filter layer 1 is formed on the inner surface of the lower substrate 16.
9, an ITO common electrode 21 and an 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 an active matrix circuit. As shown in FIG. 3, 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 includes a thin film transistor (TF).
T) 34 to the data bus line 30 and the gate bus line 32. FIG. 4 shows a color filter layer 19 of the lower substrate 16, which is a color filter (R, G, B) 19a provided corresponding to the pixel electrode 24, and a black matrix 19 for opening the color filter 19a.
b.

As shown in FIG. 1, the alignment film 22 of the lower substrate 16 and the alignment film 26 of the upper substrate 18 have been subjected to alignment processing 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 each include a lower alignment agent layer 51 and an upper alignment agent layer 53 which are provided by being laminated. Is patterned so as to have an opening corresponding to one minute region. Then, the upper alignment agent layer 53 and the lower alignment agent layer 51 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 area. The pretilt is different from that of the liquid crystal molecules 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 the minute region where the molecules are adjacent to each other.

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

FIG. 1 shows a state in which the molecules of the liquid crystal 20 in the minute areas A and B are twisted, and the molecules of the liquid crystal are viewed from the plane shown in FIG. Are shown with circles. In the minute region B , the molecules of the liquid crystal in contact with the alignment agent layer 53 on the upper side of the alignment film 22 of the lower substrate 16 have an alignment direction from the back right to the front left, and pretilt at an angle α _1. ing. The molecules of the liquid crystal in the middle part are oriented in a direction substantially parallel to the plane of FIG. 1, and the molecules of the liquid crystal in contact with the alignment agent layer 51 on the lower side of the alignment film 26 of the upper substrate 18 are moved from the left back to the right It is oriented in the forward direction, and is pretilt at an angle α ₂ . In this case, the direction of angle α ₁ is greater than the angle α _2. In the present invention, the same effect is naturally obtained even when the magnitude relationship between α ₁ and α ₂ is reversed.

On the other hand, in the minute area A , the lower substrate 1
The molecules of the liquid crystal in contact with the alignment agent layer 51 on the lower side of the alignment film 22 of No. 6 have an alignment direction from the back right to the front left and are pretilted at an angle α ₂ . The molecules of the liquid crystal in the intermediate portion are oriented in a direction substantially parallel to the plane of FIG. 1, and the molecules of the liquid crystal in contact with the alignment agent layer 53 on the upper layer side of the alignment film 26 of the upper substrate 18 are moved from the left back to the right It has become oriented toward the front, and the pre-tilt and at an angle alpha _1. Again, towards the angle alpha ₁ is larger than the angle alpha _2.

Looking at the alignment film 26 of the upper substrate 18, for example, the molecules of the liquid crystal in contact with the alignment agent layer 51 on the lower side of the alignment film 26 in the minute region B are aligned in the alignment direction from the back left to the front right. And pretilt at an angle α ₂ . Molecules of the liquid crystal in contact with the upper side of the alignment material layer 3 of the alignment film 26 in the minute domain A has become the orientation direction from left back to the right front, and the pre-tilt and at an angle alpha _1. That is, in the upper substrate 18, in the minute regions A and B, the liquid crystal molecules in contact with the alignment film 26 of the upper substrate 18 are both oriented from the back left to the front right, but the pretilt angle is α ₁ . It is different in the α _2. This relationship is the same for the alignment film 22 of the lower substrate 16.

FIG. 2 is a view showing a process of forming the alignment film 26 of the upper substrate 18 comprising the lower alignment agent layer 51 and the upper alignment agent layer 53. The alignment film 22 of the lower substrate 16 can be formed in a similar process. As shown in (A), the upper substrate 1
The lower alignment agent layer 51 and the upper alignment agent layer 53 are coated on the entire surface of the pixel electrode 24, the gate bus line 30, etc., respectively. The lower alignment agent layer 51 is made of, for example, an inorganic alignment agent such as SiO ₂ / TiO ₂ , and the upper alignment agent layer 53 is made of an organic alignment agent such as polyimide having an imidization ratio of 100%. The thickness of the lower alignment agent layer 51 and the upper alignment agent layer 53 may be about 500A. Next, as shown in (B), the upper alignment agent layer 53 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 etchant is used. Actually, the upper alignment agent layer 53 is etched by a developing solution using the remaining resist as a mask during resist development. The alignment agent layer 53 on the upper side of the polyimide is easily dissolved in an alkaline etchant, but the alignment agent layer 51 on the lower side is not soluble in the etchant.

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

Therefore, the upper alignment agent layer 53 and the lower alignment agent layer 51 exposed from the upper alignment agent layer 53 are rubbed in the same direction. However, the angle of pretilt differs depending on whether the liquid crystal molecules are in contact with the upper alignment agent layer 53 or the lower alignment agent layer 51. In the test, the molecules of the liquid crystal in contact with the upper alignment agent layer 53 pretilt to an angle of about 4 degrees (α ₁ ), and the molecules of the liquid crystal in contact with the lower alignment agent layer 51 have an angle of about 4 degrees (α ₁ ). It was confirmed that the pretilt was caused to about 1 degree (α ₂ ). In the above description, the upper alignment agent layer 53 is patterned by etching. However, the upper alignment agent layer 53 may be formed by printing or the like. Also, the alignment film
It is sufficient that the pretilt can be changed by some method (for example, partial irradiation of ultraviolet rays) without using two layers. Alternatively, a transparent electrode (pixel electrode and common electrode) may be used as a lower alignment film, and polyimide may be applied as an upper alignment film, followed by patterning and rubbing.

FIG. 5 is a simplified view of the orientation state of such minute regions A and B. In the minute region A of FIG. 5, the alignment direction of the alignment agent layer 53 on the upper layer side of the alignment film 22 of the upper substrate 18 is indicated by a dashed arrow 26a. Liquid crystal molecules pretilt at a large angle α ₁ . In the minute region B, the alignment direction of the alignment agent 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 molecules of the liquid crystal on the upper substrate 18 have a large angle. α
Pretilt by ₁ .

As described above, in the minute regions A and B,
One of the substrates 16 (1
8) pretilted at large angles alpha ₁ in side, if you pre-tilt at a small angle alpha ₂ in the other substrate 18 (16) side, when applying a voltage, the liquid crystal molecules in the middle portion by the arrows in FIG. 1 As shown, it rises in the direction with a large pretilt angle. Therefore, in the minute area A in FIG. 5, the rise of the liquid crystal follows the alignment processing of the upper substrate 18 indicated by the dashed arrow 26a. In the minute area B, the rise of the liquid crystal is indicated by a solid arrow 22.
This follows the alignment processing of the lower substrate 16 indicated by a.

Therefore, the rise of the liquid crystal in the minute area A in FIG. 5 is the same as that in the liquid crystal alignment area A shown in FIG.
This is because the rising of the liquid crystal in FIG.
It is because it followed. Similarly, the rise of the liquid crystal in the minute region B in FIG. 5 is caused by the liquid crystal alignment region B shown in FIG.
Is the same as However, the lower substrate 1 shown in FIG.
The arrow 22a indicating the rubbing direction on the 6th side is the arrow 22a indicating the rubbing direction on the lower substrate 16 side of the liquid crystal alignment region A in FIG.
It is facing the opposite direction. Therefore, the molecules of the liquid crystal in FIG. 5 are oriented parallel to the molecules of the liquid crystal in FIG. 6, and the pretilt directions are reversed. For this reason, the liquid crystal molecules in the minute region A in FIG. 5 are twisted in the same manner as the liquid crystal molecules in the liquid crystal alignment region A in FIG. 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. When rising to the larger one, the behavior of the molecules of the liquid crystal with a small pretilt angle turned in the opposite direction seems to be unstable. Nevertheless, it has been 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 for this is that, in the present invention, as described with reference to FIG. 2, it is only necessary to perform the rubbing process once near the end of the alignment process to form a plurality of alignment states. . Since the lower substrate 16 and the lower substrate 18 can be assembled in a so-called hot state without any time from the rubbing operation and without any other processing and processes, and the liquid crystal 20 can be immediately injected, the rubbing process is performed. It is considered that the liquid crystal 20 can be sealed in a state where there is no change with time. That is, according to the present invention, the rubbing process is less disturbed and the rubbing effect is smaller than in the conventional case where the exposure and etching are performed after the first rubbing is performed and then the second rubbing is performed. It seems to be stable.

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

FIGS. 3 and 4 are diagrams showing examples of setting minute regions A and B having different alignment states of the liquid crystal. As described above, on the inner surface of the upper substrate 18, the pixel electrodes 24 are provided in the respective sections of the data bus lines 30 and the gate bus lines 32 that extend vertically and horizontally in a matrix. On the lower substrate 16,
Color filters (R, G, B) corresponding to the pixel electrodes 24
19a is provided. Color filter (R, G, B) 1
9a is surrounded by a black matrix 19b. In such a configuration, the minute regions A and B having different alignment states of the liquid crystal are formed by the pixel electrodes 24 (and the color filters (R
G, B) 19a), which is divided by a line passing substantially in the center. When the pixel electrode 24 is formed to be long in a direction parallel to the data bus line 30, the minute regions A and B having different alignment states of the liquid crystal are arranged so that the gate bus line 32 crosses each pixel electrode 24 in the horizontal direction. Are provided in the form of stripes in parallel.

As shown in FIG. 7, minute regions A and B having different alignment states of the liquid crystal can be separated by a line passing between adjacent pixel electrodes 24. More specifically, minute regions A and B having different alignment states of the liquid crystal are formed in a stripe shape in parallel with the data bus lines 30 and are separated by lines passing over the data bus lines 30.

FIG. 10 is a diagram showing the contrast ratio with respect to the viewing angle in the normally white mode. The curve plotting the round 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 changed for each minute region according to the present invention. Is the contrast ratio. According to the present invention, the contrast ratio can be improved at a wide viewing angle. In addition,
The right part of the curve plotting the round points has a high contrast ratio, but this part includes a part where the brightness is inverted as described with reference to FIG.

FIG. 11 is a diagram showing a contrast ratio when used in a normally black mode. Similarly, the dot curve is a contrast ratio of a conventional liquid crystal display device having a uniform orientation, and the cross point curve is a liquid crystal display in which the liquid crystal orientation state is changed for each minute area according to the present invention. This is the contrast ratio of the device. According to the present invention, the contrast ratio can be improved at a wide viewing angle.

[0040]

As described above, according to the present invention,
An alignment process in which the alignment state of the liquid crystal differs for each minute region can be easily and reliably performed, and a liquid crystal display device having excellent viewing angle characteristics and contrast can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIGS. 2A and 2B are views showing the alignment treatment of FIG. 1, wherein FIG. 2A shows the formation of two alignment agent layers, FIG. 2B shows the patterning of the upper alignment agent layer, (C) is a diagram showing the rubbing.

FIG. 3 is a diagram illustrating an example of an alignment process for one substrate.

FIG. 4 is a diagram illustrating an example of an alignment process for the other substrate.

FIG. 5 is a diagram simply showing the alignment processing of FIG. 1;

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

FIG. 7 is a diagram showing another example of the alignment processing of one substrate.

FIG. 8 is a diagram showing one of the liquid crystal alignment regions in FIG. 6,
(A) is a diagram showing the alignment state of the liquid crystal molecules of each part,
(B) is a simplified diagram of (A), (C) is Y- of (B).
It is Y 'line sectional drawing.

FIG. 9 is a diagram illustrating viewing angle characteristics of a liquid crystal display device.

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

FIG. 11 is a diagram showing a contrast ratio in a normally black mode.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 64-79725 (JP, A) JP-A-4-191822 (JP, A) JP-A 64-82016 (JP, A) JP-A 5- 5886 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G02F 1/1337

Claims (8)

(57) [Claims] The first and second opposed substrates (16, 1
8) and an electrode (21) provided on an inner surface of the first substrate.
And 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 films.
Becomes because the inserted liquid crystal (20) between the substrate, the liquid crystal
And second minute regions (A,
B) the orientation film (22) of the first substrate so as to include
The alignment film (26) of the second substrate is divided and subjected to alignment treatment.
And liquid crystal molecules in contact with the alignment film (22) of the first substrate.
Is the orientation direction in the first and second minute regions (A, B).
Having the same and different pretilt from each other,
The molecules of the liquid crystal in contact with the alignment film (26) are the first and second molecules.
The orientation directions are the same in the micro areas (A, B) but different from each other
A first and a second minute area having a pretilt;
(A, B), the arrangement of the first substrates facing each other
Contact the orientation film (22) and the orientation film (26) of the second substrate.
A liquid crystal display device characterized in that the liquid crystal molecules have different pretilts from each other . 2. An alignment agent layer (51) on a lower layer side and an alignment on an upper layer side provided by laminating an alignment film (22) of the first substrate and an alignment film (26) of the second substrate, respectively. Agent layer (5
3), characterized in that the upper layer side of the alignment agent layer (53) is the first
Or liquid crystal display device according to claim 1, characterized in that formed by patterning so as to open in response to the second small region. 3. The alignment agent layer (51) on the lower layer side is made of an inorganic alignment agent, and the alignment agent layer (53) on the upper layer side is made of an organic alignment agent. 3. The liquid crystal display device according to 1. 4. One of the first and second substrates is a common electrode, the other electrode of the first and second substrates is a pixel electrode, and the first and second substrates have different alignment states of the liquid crystal . And the second
2. The liquid crystal display device according to claim 1, wherein the minute area is divided by a line passing substantially at the center of the pixel electrode. 5. One of the first and second substrates is a common electrode, the other of the first and second substrates is a pixel electrode, and the first and second substrates have different alignment states of the liquid crystal . And the second
2. The liquid crystal display device according to claim 1, wherein the minute area is divided by a line passing between adjacent pixel electrodes. 6. The method according to claim 1, wherein the first minute area (A)
Of liquid crystal molecules in contact with the alignment film (26) of the substrate 2
In the second minute area (B).
Pretilt of liquid crystal molecules in contact with the alignment film (22) of the substrate
And α1 in the first minute area (A).
Of liquid crystal molecules in contact with the alignment film (22) of the first substrate.
In the pretilt and the second minute area (B),
The pretreatment of liquid crystal molecules in contact with the alignment film (26) of the second substrate.
Let α2 be the tilt and satisfy the relationship of α1> α2
The liquid crystal display device according to claim 1, wherein: 7. A first and second opposing substrate (16, 1).
8) and an electrode (21) provided on an inner surface of the first substrate.
And an alignment film (22) provided on the inner surface of the second substrate.
Electrode (24) and alignment film (26), and the first and second electrodes
Of liquid crystal comprising liquid crystal (20) inserted between substrates
A method of manufacturing a display device, As the alignment films (22, 26) of the first and second substrates,
Lower aligning agent layer (51) and upper aligning agent layer to be laminated
Forming (53); The upper layer is exposed so that the lower alignment agent layer (51) is exposed.
After selectively opening the side alignment agent layer (53), The upper alignment agent layer (53) and the lower alignment agent layer
By simultaneously rubbing (51) with the upper layer side
To the alignment agent layer (53) and the lower alignment agent layer (51).
Make sure that the pretilt of the liquid crystal molecules
A method for manufacturing a liquid crystal display device. 8. The first and second opposed substrates (16, 1).
8) and an electrode (21) provided on an inner surface of the first substrate.
And 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 films.
A liquid crystal display device comprising a liquid crystal (20) inserted between substrates of the first and second substrates, wherein each of the alignment films (22, 26) of the first and second substrates is
On the other hand, by selectively irradiating ultraviolet rays to the divided minute regions (A, B) including the display unit , the first and second regions are selectively irradiated.
Wherein the pretilt of liquid crystal molecules in contact with each of the alignment films (22, 26) of the substrate is different from each other in a region irradiated with the ultraviolet light and a region not irradiated with the ultraviolet light.