JP2914851B2 - 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 substrate, and 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 one 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).

In a liquid crystal display panel, liquid crystal molecules are aligned and pretilted according to the rubbing direction of the alignment films on both substrates. In a twisted nematic liquid crystal display device, the rubbing directions of the alignment films of the two substrates are substantially perpendicular to each other, and liquid crystal molecules are twisted in a spiral form from one substrate to the other substrate. Then, 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 turning along the twist of the liquid crystal and exits from the liquid crystal panel. At this time, a white display is obtained in the normally white mode in which the polarizing plates are orthogonally arranged. 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.

In the liquid crystal display device, the contrast of light and dark of an image changes depending on the direction in which a viewer views the screen. This is generally recognized as a viewing angle characteristic of a liquid crystal display device. For example, even when an image having a good contrast between light and dark is obtained when the liquid crystal display device is viewed from directly in front, when the same image is viewed from obliquely above and below 30 degrees with respect to the horizontal, the contrast between bright and dark is obtained. Decrease. For example, when the image is viewed obliquely from above, an overall whitish image is obtained, and when the image is viewed obliquely from below, an image having a high contrast is obtained when the applied voltage is low. Worse,
It may be inconvenient to obtain neutral colors.

In order to solve the influence of the viewing angle characteristic, Japanese Patent Application Laid-Open No. 54-5754 and Japanese Patent Application Laid-Open
Japanese Patent No. 6624 discloses that a unit area for one pixel is divided into two minute areas having different orientations of liquid crystal (referred to as pixel division or orientation division), and one area is rubbed in one direction and the other area is rubbed. Proposes performing rubbing in the opposite direction. By such pixel division, the two viewing angle characteristics viewed from the obliquely upper side and the obliquely lower side are averaged,
It is possible to improve the viewing angle characteristics as a whole.

In a liquid crystal display device in which pixels are divided, rubbing in the opposite direction must be performed for each of two minute regions. Such a rubbing process requires the following two rubbing processes using a lithography technique. That is, 1
In the rubbing process for the first time, an alignment film is applied to the inner surface of the substrate,
A step of applying a resist to the alignment film, providing an opening corresponding to one of the minute regions in the resist, rubbing the resist in a certain direction there, and removing the resist. Then, in the second rubbing treatment, a resist is applied to the alignment film subjected to the first rubbing, and an opening corresponding to a region opposite to the one region is provided in the resist,
Then, rubbing in the reverse direction and removing the resist are performed.

In such a rubbing process, it is necessary to perform two photolithography processes and two rubbing processes on the alignment film of each substrate. Therefore, it was necessary to perform a total of four photolithography processes and four rubbing processes on both substrates.
However, since the photolithography process and the rubbing process are performed many times as described above, the manufacturing cost increases, and
There is a problem that the surface of the alignment film is rough and the alignment of the liquid crystal is not stable.

In order to solve such a problem, the applicant of the present application has proposed in the prior application that by appropriately controlling the pretilt angle of the liquid crystal, the alignment film of each substrate can be formed in a pixel by only one rubbing step. It is proposed that it can be split. In the simplest process, the alignment film of one substrate is formed solid and rubbed so that the pretilt angle of the liquid crystal becomes a certain value β, but the alignment film of the other substrate is formed in a two-layer structure. In this case, the upper alignment material layer is provided with an opening corresponding to the fine region, and one rubbing process is performed from above. The lower alignment material layer and the upper alignment material layer have different materials, for example, so that when rubbed in the same manner, the pretilt angle of the liquid crystal becomes α in the upper alignment material layer, and In the lower alignment material layer exposed from the opening of the alignment material layer, the pretilt angle of the liquid crystal becomes γ, and the relationship α>β> γ is satisfied. Here, the single rubbing process includes moving the rubbing roller a plurality of times in the same direction. The fact that the pixel can be divided by this will be described later in detail.

[0009]

As described above, pixel division can be achieved by forming two minute regions where the pretilt angles α and γ of the liquid crystal are different from each other on at least one substrate. Can be simplified,
There is an advantage that the alignment of the liquid crystal is stabilized without deteriorating the surface of the alignment film. However, in the prior application, this was achieved by forming the alignment film of the substrate in a two-layer structure. The object of the invention is to further simplify the structure,
It is an object of the present invention to provide a liquid crystal display device and a method for manufacturing the same, which are capable of forming two minute regions in which a pretilt angle of a liquid crystal in contact with the single alignment film is different from each other.

[0010]

According to a method of manufacturing a liquid crystal display device according to the present invention, a first substrate having an alignment film is provided.
And a second substrate facing the first substrate and having an alignment film 22.
And a liquid crystal 20 inserted between the first and second substrates, and at least the alignment film 2 of the first substrate.
2 comprises a single layer of an alignment material layer having first and second adjacent minute regions A and B, wherein the single layer of the alignment material layer is located on the first and second minute regions A and B. A method for manufacturing a liquid crystal display device which is continuously rubbed in one direction along
Selectively in the first and second minute regions A and B.
It is characterized by performing a suitable reforming treatment .

[0011] Also, a method of manufacturing a liquid crystal display device according to the invention, a second substrate 16 having the first substrate 18, the first substrate opposed to and oriented film 22 having an alignment film 26
And a liquid crystal 20 inserted between the first and second substrates, and at least the alignment film 26 of the first substrate
And a single-layer alignment material layer having second adjacent minute regions A and B, wherein the single-layer alignment material layer extends in one direction along the first and second minute regions A and B. A method of manufacturing a continuously rubbed liquid crystal display device, comprising:
And the second minute regions A and B are selectively subjected to a reforming process, and the reforming process is performed for a chemical component that controls the pretilt angle of the surface of the first and second minute regions A and B. Selectively changing the concentration distribution, wherein the first
And selectively changing the concentration distribution of the chemical component that governs the pretilt angle on the surface of the second minute regions A and B comprises selectively changing the concentration distribution of the chemical components governing the pretilt angles on the surfaces of the first and second minute regions A and B. And a step of attaching a material layer for increasing or decreasing the pretilt angle. Also, the liquid according to the present invention
The method for manufacturing a crystal display device includes a first substrate having an alignment film 26.
A plate 18 and an alignment film 22 facing the first substrate;
A second substrate 16 inserted between the first and second substrates.
, And at least the arrangement of the first substrate.
The facing film 26 has first and second adjacent minute regions A and B
Comprising a single layer of alignment material having
The layer is oriented in one direction along the first and second minute regions A and B.
For manufacturing liquid crystal display device continuously rubbed on a substrate
And a solvent after applying the alignment material to the first substrate.
The first and second minute regions so that the volatilization time changes
A and B are selectively cured.

[0012]

In the above-described structure, the alignment film 26 of the first substrate has the same orientation direction of the liquid crystal and the first and second adjacent minute regions A and B having different pretilt angles α and γ.
Having. For the second substrate, for example, the alignment film 22 of the second substrate may have substantially the same alignment direction and pretilt angle β in the first and second adjacent minute regions A and B, and α> β > Γ. In the above configuration, the alignment films of the first and second substrates are both of a single-layer structure, and the structure is simpler than the conventional one. Also,
The second substrate can also have first and second adjacent minute regions B and A in which the orientation directions of the liquid crystal are the same and the pretilt angles α and γ are different from each other.

When there is a relationship of α>β> γ, in the first region A, the pretilt angle of the liquid crystal in contact with the first substrate is α, and the pretilt angle of the liquid crystal in contact with the second substrate is β. . In the second region B, the pretilt angle of the liquid crystal in contact with the first substrate is γ, and the pretilt angle of the liquid crystal in contact with the second substrate is β. The liquid crystal molecules located in the middle between the first substrate and the second substrate are in the first state when a voltage is applied.
The first region A has a property of rising according to the direction of the liquid crystal in contact with the first substrate, and the second region B has a property of rising according to the larger pretilt angle of the substrate and the second substrate. In (2), the rising (tilt) follows the direction of the liquid crystal in contact with the second substrate, and pixel division can be achieved.

[0014]

FIG. 1 is a view showing a liquid crystal panel 10 of a liquid crystal display according to a first embodiment of the present invention. This liquid crystal panel 10
Polarizing plates 12 and 14 are arranged on both sides in a vertical relationship in a normally white mode or in a parallel relationship in a normally black mode. LCD panel 10
Is a liquid crystal 20 between a pair of transparent glass substrates 16 and 18.
Is enclosed. Light from a light source (not shown) enters the liquid crystal panel 10 from the direction of the arrow L, and a viewer views the liquid crystal panel 10 from a direction opposite to the incident direction. The substrate 16 is called a lower substrate, and the substrate 18 on the viewer side is called an upper substrate. However, the light incident side and the viewer side can be reversed.

On the inner surface of the lower substrate 16, a common electrode 2 of ITO is provided.
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. A color filter layer (not shown) is provided below the common electrode 21 of the lower substrate 16. The common electrode 21 and the pixel electrode 24 can be provided in reverse. As shown in FIG. 2, the pixel electrode 24 provided on the upper substrate 18 is connected to an active matrix circuit. The active matrix circuit includes a data bus line 30 and a gate bus line 32 that extend vertically and horizontally in a matrix.
T) 34 to the data bus line 30 and the gate bus line 32.

As shown in FIG. 2, each pixel area represented by the pixel electrode 24 is divided into two small areas A and B. The division pattern shown in FIG. 2 is formed in a stripe shape by a line passing through the center of one horizontal row of pixel electrodes 24. For example, in the horizontal one row of pixel electrodes 24, two minute regions A and B are alternately arranged. A staggered pattern can also be used.

The liquid crystal 20 uses a twisted nematic liquid crystal. Figure 1 shows the basics of rubbing and alignment division when using a twisted nematic liquid crystal.
This will be described with reference to FIGS. FIG. 18 shows an example of rubbing when a twisted nematic liquid crystal (without alignment division) is used, and the solid arrow 22a indicates the lower substrate 18.
The rubbing direction applied to the alignment film 22 of the upper substrate 16 is shown by a dashed arrow 26a.

FIG. 19 shows the liquid crystal molecules 20 in contact with the alignment film 22 of the lower substrate 16 when such a rubbing process is performed.
L and liquid crystal molecules 20U in contact with the alignment film 26 of the upper substrate 18.
And a liquid crystal molecule 20C located in the middle between the lower substrate 16 and the upper substrate 18, respectively. FIG.
In each figure, the left-hand drawing of each step is a plan view showing the orientation direction of the liquid crystal molecules as viewed in correspondence with FIG. The alignment direction of the liquid crystal molecules 20L in contact with the alignment film 22 of the lower substrate 16 coincides with the rubbing direction 22a of the alignment film 22 of the lower substrate 16, and is directed downward to the right.
The alignment direction of the liquid crystal molecules 20U in contact with 6 coincides with the rubbing direction 26a of the alignment film 26 of the upper substrate 18, and is directed to the left ascending direction. The liquid crystal twists counterclockwise between the lower substrate 16 and the upper substrate 18, and the liquid crystal molecules 20 </ b> C in the middle are in a uniform orientation in which the liquid crystal molecules are directed to the left.

FIG. 20 is a sectional view of the rubbed liquid crystal panel 10 shown in FIG. 18 taken along the line XXＸXX in FIG. Arrow C indicates that the liquid crystal panel 10 is
The arrow U indicates the liquid crystal panel 1
0 indicates that the liquid crystal panel 10 is viewed obliquely upward from 30 degrees, and the arrow L indicates that the liquid crystal panel 10 is viewed obliquely downward from 30 degrees.

FIG. 21 is a diagram showing the viewing angle characteristics of the rubbed liquid crystal panel 10 shown in FIG. 18, and the dashed line C indicates the voltage / transmission when the liquid crystal panel 10 is viewed from the direction of arrow C in FIG. It is a rate curve. Dashed lines U and L are voltage / transmittance curves when the liquid crystal panel 10 is viewed from the directions of arrows U and L in FIG. 20, respectively. 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 dashed line U, when a small voltage is applied, the transmittance is greatly reduced, and an image having a large contrast ratio is obtained.
As the voltage increases, the transmittance increases again, and the correspondence between the voltage and the transmittance reverses, which may be inconvenient for obtaining an intermediate color between white and black.

In order to improve such viewing angle characteristics, pixel division is performed as shown in FIG. FIG. 22 shows a basic form of pixel division having a minute area A and a minute area B. In the minute area A, the same rubbing processing as in FIG. 18 is performed. In the minute area B, a rubbing process reverse to that in the minute area A is performed. That is, the direction of the dashed arrow 26a of the minute area B is the same as that of the dashed arrow 26a of the minute area A.
, The solid arrow 22a of the minute area B
Is opposite to the direction of the solid arrow 22a in the minute area A. As a result, the liquid crystal molecules 20C located in the middle between the lower substrate 16 and the upper substrate 18 of the minute region B face the opposite direction to those of the minute region A, and the viewing angle characteristics are also reversed.

When such a minute area A and a minute area B are arranged next to each other, when the liquid crystal display panel 10 is viewed from the direction of the arrow U or L in FIG. 20, the characteristic indicated by the solid line I in FIG. 21 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. This is the effect of pixel division. But,
In order to perform the rubbing shown in FIG. 22, it is necessary to perform rubbing twice for each substrate, as described above. Such a process is troublesome, and the applicant of the present application proposed an orientation process (one example) shown in FIGS. 23 and 24 in the above-mentioned prior application.

In FIG. 23, the rubbing processing of the minute area A is the same as the rubbing processing of the minute area B.
That is, rubbing may be performed in the direction of the arrow 22a through the minute regions A and B on the alignment film 22 of the lower substrate 16, and the direction of the arrow 26a through the minute regions A and B on the alignment film 26 of the upper substrate 18. Rubbing may be performed. However, it is necessary that the pretilt angle of the liquid crystal be as shown in FIG.

In FIG. 24, the alignment film 2 of the lower substrate 16 is
Reference numeral 2 denotes a single-layer structure in which the pretilt angle of the liquid crystal in contact with the rubbed film is β. The alignment film 26 of the upper substrate 18 has a two-layer structure including a lower alignment material layer 51 and an upper alignment material layer 52, and the upper alignment material layer 52 corresponds to a minute region A or B. It is patterned so as to open. The upper alignment material layer 52 is made of a material having a relatively large pretilt angle α of the liquid crystal in contact with the rubbed liquid,
The lower alignment material layer 51 is made of a material that, when rubbed, has a relatively small pretilt angle γ of the liquid crystal in contact with it. Here, there is a relationship of α>β> γ.

Then, in the minute region A, the pretilt angle of the liquid crystal molecules on the lower substrate 16 side is β, and the upper substrate 1
The pretilt angle of the liquid crystal molecules on the eight side is γ, and β> γ. In the minute region B, the pretilt angle of the liquid crystal molecules on the lower substrate 16 side is β, and the pretilt angle of the liquid crystal molecules on the upper substrate 18 side is α, and α> β. In the prior application, the inventors of the present application have found that if there is a certain difference between the upper and lower pretilt angles in this manner, the intermediate liquid crystal molecules 20C between the lower substrate 16 and the upper substrate 18 will have a lower pretilt angle when a voltage is applied. Stand up according to the larger rubbing (tilt)
I discovered that. It has been found that the light transmission characteristics of the liquid crystal are determined mainly by the behavior of the intermediate liquid crystal molecules 20C.

Therefore, in FIG. 24, the liquid crystal molecules 20C in the middle of the minute region A rise in the rubbing direction of the alignment film 22 of the lower substrate 16. The rubbing direction of the alignment film 22 of the lower substrate 16 in FIG.
a, which is the same as the rubbing direction 22a of the small area A in FIG. Therefore, FIG. 23 and FIG.
The viewing angle characteristics of the small area A in FIG. 4 are the same as the viewing angle characteristics of the small area A in FIG.

Similarly, the liquid crystal molecules 20C in the middle of the minute region B in FIG. 24 are aligned according to the rubbing direction of the alignment film 26 of the upper substrate 18. The rubbing direction of the alignment film 26 on the upper substrate 18 in FIG. 24 corresponds to the rubbing direction 26a in FIG. 23, and this is the same as the rubbing direction 26a in the minute region B in FIG. Therefore, the viewing angle characteristics of the minute region B in FIGS. 23 and 24 are the same as the viewing angle characteristics of the minute region B in FIG. That is, the processing of FIGS. 23 and 24 can achieve the same effect of pixel division as that of FIG. 22, and the manufacturing of FIGS. 23 and 24 is simpler because each substrate requires only one rubbing. Is stabilized.

The present invention further improves this prior application, and FIG.
As shown in FIG. 2, for example, the orientation film 26 of the upper substrate 18 has a single-layer structure so that different pretilt angles α and γ can be realized for each of the minute regions A and B.
As shown in FIG. 32, the upper substrate 18 and the lower substrate 1
6, the pre-tilt angles α and γ different for each of the minute regions A and B can be formed as a single layer structure. The upper and lower pretilt angles α and γ face each other.
Hereinafter, the configuration of FIG. 1 will be mainly described. For this reason, in the present invention, as shown in FIG. 23, the single-layer alignment film 26 is continuously rubbed in one direction along the two minute regions A and B, and as will be described below. The rubbing process is performed so that the pretilt angles α and γ of the liquid crystal in contact with the alignment film 26 in the two minute regions A and B are different from each other.

FIG. 3 is a view showing a first embodiment of the processing for changing the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18. In FIG. 3, in FIG.
The alignment film 26 is applied to the surface of the substrate 8 by spin coating.
Here, the application of the alignment film 26 to the surface of the upper substrate 18 means that the alignment film 26 is applied to the surface of the pixel electrode 24 or any other material formed on the upper substrate 18. is there. As the alignment film 26, a polyimide having a high pretilt angle and an imidization ratio of 100% was used. This kind of polyimide is usually called a soluble polyimide and is obtained by dissolving various kinds of polyimide components in a solvent. The polyimide component contains a chemical component such as a diamine component, which particularly controls the pretilt angle.
As such an alignment material, for example, J. Synthetic Rubber J
ALS 219, 214, etc. can be used.

In FIG. 3B, the alignment film 26 of the upper substrate 18 is cured in an oven or the like to remove the solvent and cure the alignment film 26. Then, FIG. 3 (c)
, The minute regions A and B are selectively irradiated with ultraviolet rays using the mask 60. The mask 60 is a plate 60a made of a material made of quartz or synthetic quartz that transmits ultraviolet light.
And an ultraviolet shielding material layer 60b such as chromium provided on the plate corresponding to one of the minute regions A and B. 3D, the rubbing roller 57 is used to rub the alignment film 26 as shown in FIG.

FIG. 4 is a diagram showing a second embodiment of the processing for changing the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18. In this embodiment, similar to the embodiment of FIG.
(A), an alignment film 26 is applied to the surface of the upper substrate 18, and (b), the alignment film 26 of the upper substrate 18 is cured. Then, contrary to the embodiment of FIG. 3, the alignment film 26 is rubbed in (c), and the minute regions A and B are selectively irradiated with ultraviolet rays using the mask 60 in (d).

In FIGS. 3 and 4, a minute area A,
By selectively irradiating B with ultraviolet light, the minute region A not irradiated with ultraviolet light has a high pretilt angle α according to the properties of the polyimide used as the alignment material and according to the rubbing before and after it. On the other hand, in the minute region B irradiated with ultraviolet rays, the surface energy of the alignment film 26 in that portion increases, and the properties of the initial polyimide and the pretilt angle γ become smaller than in the case where a predetermined rubbing is performed. Thereby, for example, when the pretilt angle α is 8
Degree, the pretilt angle β is 4 degrees, and the pretilt angle γ is 1 degree.

The fact that the pretilt angle γ is reduced by irradiating ultraviolet rays is shown in the relationship between FIG. 5 and FIG. As shown in FIG. 5, the longer the irradiation time of the ultraviolet light, the smaller the pretilt angle. Irradiation of ultraviolet rays increases the surface energy of the alignment film 26. As shown in FIG. 6, as the surface energy of the alignment film 26 increases, the wettability of the alignment film 26 improves, and the contact angle decreases.
Then, the pretilt angle becomes smaller. The experimental fact that the pretilt angle decreases as the surface energy of the alignment film 26 increases will be used in later examples.

In order to reduce the pretilt angle by using ultraviolet irradiation, it is necessary to use ultraviolet light having energy enough to break the polyimide bond on the surface of the alignment film 26. For this purpose, it is desirable to use ultraviolet light having a wavelength of 300 nm or less, and more preferably to use ultraviolet light having a wavelength of 260 nm or less. In the examples, mainly 253.7 nm and 184.9 n
10mW low-pressure mercury lamp that emits ultraviolet light of wavelength m
/ Cm ² .

FIG. 7 is a diagram showing an example of obtaining a combination of the alignment film 26 of the upper substrate 18 and the alignment film 22 of the lower substrate 16 as shown in FIG. In this embodiment, the alignment film 26 of the upper substrate 18 and the alignment film 2 of the lower substrate 16 are used.
Second, the same alignment material is used so that the liquid crystal exhibits the same pretilt angle when the same rubbing treatment is performed.

FIG. 7A shows an alignment process of the alignment film 26 of the upper substrate 18. First, the entire surface is rubbed with a rubbing roller 57 so that the liquid crystal contacting the alignment film 26 has a pretilt angle α. Then, the mask 60 is used to irradiate ultraviolet rays, so that the pretilt angle is kept at α in the minute area B where the ultraviolet rays have not hit, and the pretilt angle is γ in the minute area A where the ultraviolet rays have hit. Note that rubbing and ultraviolet irradiation may be performed in the reverse order. FIG.
(B) shows the alignment treatment of the alignment film 22 of the lower substrate 16, and the entire surface is first rubbed with the rubbing roller 57.
The liquid crystal in contact with is made to have a pretilt angle α, and then is irradiated with ultraviolet light without using a mask, so that the pretilt angle becomes β. In this case, rubbing and ultraviolet irradiation may be performed in the reverse order. Thus, the alignment films 22 and 26 satisfying the relationship α>β> γ can be obtained.

FIG. 8 shows another embodiment of the combination of the alignment film 26 of the upper substrate 18 and the alignment film 22 of the lower substrate 16. FIG.
(A) shows an alignment process of the alignment film 26 of the upper substrate 18, and the entire surface is first rubbed with a rubbing roller 57.
The liquid crystal in contact with is set to have a pretilt angle α. Then, the mask 60 is used to irradiate ultraviolet rays, so that the pretilt angle is kept at α in the minute area B where the ultraviolet rays have not hit, and the pretilt angle is γ in the minute area A where the ultraviolet rays have hit.

FIG. 8B shows the alignment treatment of the alignment film 22 of the lower substrate 16, in which the liquid crystal in contact with the alignment film 26 is rubbed so as to have a pretilt angle β. In this case, the same material may be used as the alignment material of the alignment films 26 and 22, or different materials may be used. In short, the pretilt angle is made different depending on the combination of the alignment material and the rubbing. When the same alignment material is used, the number of rubbings is increased or decreased so that the pretilt angle differs.
Also in this case, it is necessary to satisfy the relationship α>β> γ.

FIG. 9 relates to the improvement of the mask 60 used for changing the pretilt angles α and γ by the above-mentioned ultraviolet irradiation. The mask 60 is formed by attaching an ultraviolet ray blocking material layer 60b made of chromium that blocks ultraviolet rays to a plate 60a made of quartz or synthetic quartz that transmits ultraviolet rays. In this embodiment, the plate 60a that transmits the ultraviolet rays has the projections 60c, and the ultraviolet shielding material layer 60
b is attached to the surface of the projection 60c. Therefore, the surface of the ultraviolet ray blocking material layer 60b protrudes from the surface 60d of a portion of the plate 60a that allows the ultraviolet ray to pass between the ultraviolet ray blocking material layers 60b.

According to this configuration, the ultraviolet shielding material layer 60
UV irradiation can be performed by bringing b closer to or in contact with the alignment film 26 of the upper substrate 18 as much as possible. In this manner, as shown by the arrow P, it is possible to prevent the ultraviolet light from entering the region below the ultraviolet shielding material layer 60b when obliquely incident on the mask 60. If the ultraviolet ray blocking material layer 60b is located at the position indicated by the broken line 60e, the ultraviolet ray indicated by the arrow P goes around the ultraviolet ray blocking material layer 60e and enters the region of the alignment film 26 where the ultraviolet ray is to be blocked. Not preferred.

When the plate 60a is flat, in order to prevent ultraviolet rays from flowing around the ultraviolet ray blocking material layer 60e, the plate 6a
It is desirable to bring the entire Oa as close as possible to the alignment film 26, but in this case, the surface 60d of the portion of the plate 60a opened between the ultraviolet blocking material layers 60b is too close to the alignment film 26. Surface 60d of opening of mask 60 and upper substrate 18
It was found that when the gap between the film and the alignment film 26 was small, the amount of ozone generated in the gap was small, and the effect of modifying the surface of the alignment film 26 by ultraviolet irradiation was reduced. That is, FIG. 10 shows a gap between the surface 60 d of the opening portion of the mask 60 and the alignment film 26 of the upper substrate 18,
This shows the relationship with the surface energy of the alignment film 26 (related to the pretilt angle). The smaller the gap is, the smaller the surface energy of the alignment film 26 is. Therefore, it is desirable that the ultraviolet ray blocking material layer 60b be as close as possible to the alignment film 26, and that there be an appropriate gap between the surface 60d of the opening and the alignment film 26 of the upper substrate 18.

FIG. 11 shows that the ultraviolet ray blocking material layer 60b attached to the ultraviolet ray transmitting plate 60a of the mask 60 is made of a material having a relatively large thickness, and thus performs the same operation as that of FIG. FIG. In this case, it is desirable that the ultraviolet shielding material layer 60b is made of an ultraviolet shielding resin.

FIG. 12 shows a structure in which a spacer 6 is provided between a plate 60a of the mask 60 which transmits ultraviolet light and an ultraviolet shielding material layer 60b.
FIG. 10 is a diagram showing an example in which 0f is provided, so that the same operation as that of FIG. 9 is performed. In this case, the ultraviolet blocking material layer 60b is made of chromium, and the spacer 60f is made of an appropriate resin.

FIG. 13 is a view showing a third embodiment of the processing for changing the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18. In this embodiment, the distribution of the chemical component that controls the pretilt on the surface of the minute regions A and B is selectively changed. In FIG. 13, (a) shows the upper substrate 1
8, the alignment film 26 of the upper substrate 18 is cured in (b), and a resist mask 54 is formed on the alignment film 26 in (c) to form a small region A of the alignment film 26. Is slightly etched, and the alignment film 26 is rubbed using the rubbing roller 57 as shown in FIG.

FIG. 14 is an enlarged view showing a part of the alignment film 26 etched in FIG. As described above, the material of the alignment film 26 made of polyimide is usually referred to as soluble polyimide, and is obtained by dissolving various kinds of polyimide components in a solvent. The polyimide component includes a chemical component such as a diamine component, which particularly controls the pretilt angle, and a chemical component that does not significantly affect the pretilt angle. The chemical component that controls the pretilt angle usually shows hydrophobicity, and tends to concentrate on the surface in a low humidity atmosphere such as air or nitrogen. If the temperature of the precure in the curing of the alignment film 26 is as low as possible,
The chemical components governing the pretilt angle become considerably concentrated on the surface.

FIG. 14 shows that the chemical components governing the pretilt angle are concentrated on the surface of the alignment film 26 by hatching. When the surface of the alignment film 26 on which the chemical components governing the pretilt angle are concentrated is selectively changed, a portion containing many chemical components governing the pretilt angle and a portion lacking such components are formed. Thus, the pretilt angles α and γ of the liquid crystal can be made different. In the embodiment, etching is used as a means for changing the shape of the surface of the alignment film 26,
In FIG. 14, the surface portion 26x corresponding to the minute region A of the alignment film 26 is slightly removed by the etching in FIG. The adjacent minute region B contains many chemical components that govern the pretilt angle. Note that the post-curing temperature in the curing of the alignment film 26 is set as high as possible (for example, about 300 ° C.) in order to reduce the damage caused by the developing solution at the time of resist patterning.
(Orientation material, JALS-214
(In the case of Japanese synthetic rubber), 250 ° C to 300 ° C). When a polyamic acid type polyimide is used, the curing temperature is set to 200 ° C. because of its relatively high chemical resistance.
The following is also possible (for example, CRD4022, manufactured by Sumitomo Bakelite).

FIG. 15 shows an alignment film 26 between the upper substrate 18 and the alignment film 26 as means for selectively changing the distribution of a chemical component that governs the pretilt angle on the surface of the minute regions A and B. Has been treated to selectively change the hydrophobicity of the water. More specifically, an amorphous silicon layer 61 is formed as a base of the alignment film 26 in a region corresponding to the minute region A.
Are formed. Amorphous silicon having no surface oxide film is hydrophobic. Therefore, the alignment film 26 in contact with the amorphous silicon layer 61 in the minute region A
The chemical component governing the pretilt angle is concentrated near the amorphous silicon layer 61, and the chemical component governing the pretilt angle is reduced on the surface side of the alignment film 26 as a whole. FIG. 15 also shows a portion where the chemical components governing the pretilt angle are concentrated by hatching. It can be seen that the adjacent minute region B contains many chemical components that govern the pretilt angle.

FIG. 16 shows a fourth embodiment of the processing for changing the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18, and selectively changes the surface shape of the minute regions A and B (surface area). As a means for changing the above, irregularities are provided on the surface of the minute region A. When irregularities are provided on the surface of the minute region A, the surface energy of the alignment film 26 increases, and the pretilt angle decreases as described with reference to FIG. FIG.
Is an example in which unevenness is provided on the surface of the upper substrate 18, and as a result, unevenness appears on the surface of the alignment film 26. As an uneven substrate, NO 400, 600, 800, 1000 frosted glass (sand blasting) was used, and smooth glass was used to form an alignment film thereon, rubbed, and the pretilt angle (degree) was measured. The results were as follows.
The larger the sample number, the finer the eyes. Smooth 400 600 800 1000 6 1 1 1.5 1.5

FIG. 17 shows a modification of FIG.
6 shows an example in which irregularities are directly provided. A semiconductor process such as RIE─O (reactive ion etching─oxygen), RIE─Ar (reactive ion etching─argon), CDE (chemical dry etching), OA (ozone ashing), etc., for providing unevenness on the alignment film 26. And a known process can be used. The results of measuring the pretilt angle (degrees) by rubbing and measuring the pre-tilt angle (degrees) of a glass substrate on which an alignment film was formed and subjected to these treatments, and those subjected to these treatments, were as follows. No processing RIE O RIE Ar CDE OA 6 1 1 1.5 0.5 All processing above uses a commercially available positive resist as a mask, and baking of the resist is performed so that the resist can be easily peeled thereafter. The test was performed at a low temperature (for example, 120 ° C. or lower). It is considered that the dry treatment probably includes not only the effect of unevenness but also a surface modification effect equivalent to UV irradiation.

FIG. 25 is a view showing a fifth embodiment of the processing for changing the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18. This embodiment includes a step of attaching a material layer for selectively increasing or decreasing the pretilt angle to the surfaces of the minute regions A and B. More specifically, the step of depositing a material layer for increasing or decreasing the pretilt angle includes the step of selectively depositing a material layer having a property of orienting liquid crystals in a direction perpendicular to the substrate surface.

In FIG. 25, an alignment film 26 is applied to the surface of the upper substrate 18 in (a), the alignment film 26 of the upper substrate 18 is cured in (b), and the upper substrate 18 is placed in a chamber in (c). Then, nitrogen gas containing 1000 ppm of siloxane gas is introduced into the chamber 63 to adhere siloxane to the alignment film 26, and (d)
In FIG. 2, the alignment film 26 is
Rub like 3

Before (c), a resist mask 54 is formed on the alignment film 26 to cover a portion corresponding to the minute region A of the alignment film 26 and to expose a portion corresponding to the minute region B. Let it be. Therefore, in (c), the siloxane adheres to a portion corresponding to the minute region B of the alignment film 26. Siloxane is known as a material having a property of orienting liquid crystal in a direction perpendicular to the substrate surface. Therefore, the pretilt angle of the liquid crystal in the minute region B is larger than that in the minute region A where siloxane is not attached. 1
It becomes 0 degrees. In this case, an alignment material having a pretilt angle of 1 to 2 degrees when a normal rubbing process is performed is used, and the pretilt angle of the minute region A is 1 to 2 degrees. Alignment film 2 in nitrogen gas containing 1000 ppm of siloxane
In the case of the process in which 6 is left for 10 minutes, the pretilt angle of the minute area B is 6 to 7 degrees. Instead of treating the alignment film 26 in a siloxane gas, the alignment film 26 can be immersed in a siloxane solution.

FIG. 26 shows a sixth embodiment of the process for changing the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18 and comprises a step of selectively heating the minute regions A and B. 26A, the upper substrate 18 in FIG.
Is coated with an alignment film 26 on the surface of the upper substrate 1 in FIG.
8, the rubbing roller 57 is used to rub the alignment film 26 as shown in FIG. 23 in (c), and the alignment film 26 is heated from a heat source such as an infrared heater through a mask 65 in (d). 26 is selectively heated (eg, 200 ° C.). Assuming that the pretilt angle of the liquid crystal that comes into contact with the alignment film 26 when the alignment film 26 is rubbed becomes α, if the minute area A is heated using an infrared heater after the rubbing, traces of rubbing on the alignment film 26 may be slightly formed. As a result, the pretilt angle is reduced from α to γ.

FIG. 27 shows an example in which the heating means of FIG. In this case, the mask 65 has a comb-like shape having a portion 65a through which heat is transmitted and a portion 65b through which heat is blocked. The heat-transmitting portion 65a and the heat-shielding portion 65b are each substantially half the pixel pitch. FIG. 28 shows FIG.
The example in which the heating means is constituted by a laser source 67 is shown. Further, scanning means for selectively scanning the laser beam emitted from the laser source 67 is used. The scanning means comprises a polygon mirror 68, which is rotatable about its own axis, and scans the laser beam in the width direction (Y direction) of the minute area A to be heated. Further, the laser source 67 and the polygon mirror 68 are movable in the length direction (Z direction) of the minute area A to be heated. Therefore, the minute region A can be heated in a belt shape.

FIG. 29 is a view showing a fifth embodiment of the processing for changing the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18, and in FIG.
Is applied, (b) the minute regions A and B are selectively precure so as to change the solvent volatilization time. Also in this case, the upper substrate 18 is placed on the hot plate 69 and heated from above by an infrared heater. Using the mask 65, the minute region A is positively heated while shielding the minute region B.

The pretilt angle changes by the precure process, and as shown in FIG. 30, the lower the precure temperature (the longer the precure time), the larger the pretilt angle. Therefore, after pre-curing, post-curing is performed in (c) and rubbing is performed in (d),
The pretilt angle of the minute region B that is pre-cured while being shielded by the mask 65 is α, and the pretilt angle of the minute region A is γ.

FIG. 31 shows a modification of FIG. 29. In FIG. 29B, instead of selectively heating the alignment film 26 of the upper substrate 18 by the infrared heater, the alignment film 26 of the upper substrate 18 is selectively heated. Cooling down. However, since the upper substrate 18 is placed on the hot plate 69, it is heated as a whole, and the cool air adjusts the precure temperature.

[0058]

As described above, according to the present invention,
The alignment film of one of the substrates has only one layer, and the first and second minute regions in which the pretilt of the liquid crystal contacting it are different from each other can be formed, the structure is simple, the image is stable, and the viewing angle characteristics and the contrast are excellent. Liquid crystal display device can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a liquid crystal display device according to the present invention.

FIG. 2 is a diagram illustrating an arrangement of pixel electrodes in FIG. 1;

FIG. 3 is a diagram showing a first embodiment in which a pretilt is made different.

FIG. 4 is a diagram showing a second embodiment in which the pretilt differs.

FIG. 5 is a diagram showing a relationship between UV irradiation time and pretilt.

FIG. 6 is a diagram showing a relationship between surface energy and pretilt.

FIG. 7 is a diagram illustrating an example of manufacturing upper and lower substrates by UV irradiation.

FIG. 8 is a diagram showing another example of manufacturing upper and lower substrates by UV irradiation.

FIG. 9 is a view showing a modified example of a mask used for UV irradiation.

FIG. 10 is a diagram for explaining the operation of FIG. 9;

FIG. 11 is a diagram showing a modification of FIG. 9;

FIG. 12 is a view showing another modification of FIG. 9;

FIG. 13 is a diagram showing a third embodiment in which the pretilt differs.

FIG. 14 is an enlarged view of the substrate of FIG.

FIG. 15 is a diagram showing a modification of FIG.

FIG. 16 is a diagram showing a fourth embodiment in which the pretilt differs.

FIG. 17 is a diagram showing a modification of FIG. 16;

FIG. 18 is a diagram showing rubbing of a twisted nematic liquid crystal.

19 is a diagram showing the orientation of the liquid crystal molecules in FIG.

FIG. 20 is a sectional view taken along lines XX-XX in FIG. 18;

FIG. 21 is a diagram illustrating viewing angle characteristics of a twisted nematic liquid crystal display device.

FIG. 22 is a diagram showing a basic form of pixel division.

FIG. 23 is a diagram showing an advanced form of pixel division.

FIG. 24 is a diagram showing a liquid crystal display device of the prior application.

FIG. 25 is a diagram showing a fifth embodiment in which the pretilt differs.

FIG. 26 is a diagram showing a sixth embodiment in which the pretilt differs.

FIG. 27 is a diagram showing an example of the heating means of FIG. 26.

FIG. 28 is a view showing another example of the heating means of FIG. 26;

FIG. 29 is a diagram showing a seventh embodiment in which the pretilt is made different.

FIG. 30 is a diagram showing a relationship between a curing temperature and a pretilt angle.

FIG. 31 is a diagram showing a modification of FIG. 29;

FIG. 32 is a diagram showing a modification of FIG. 1;

[Explanation of symbols]

 16, 18: substrate 20: liquid crystal 22, 26: alignment film A, B: minute area

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shun Toshiki 1015 Uedanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Tadashi Hasegawa 1015 Uedanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited ( 72) Inventor Go Kamata 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Takashi Sasabayashi 1015 Kamikodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Kiyoji Tanuma Kanagawa Prefecture 1015 Kamiodanaka, Nakahara-ku, Kawasaki City Inside Fujitsu Limited (72) Inventor Takemune Mayama 1015 Kamiodanaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Katsufumi Omuro Katsufumi Omuro Nakahara-ku, Kawasaki City, Kanagawa Prefecture 1015 Odanaka Fujitsu Limited (72) Inventor Shigeru Masuda 1015 Kamiodanaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture JP-A-6-337420 (JP, A) JP-A-4-247456 (JP, A) JP-A-6-281937 (JP, A) JP-A-6-130396 (JP) JP-A-6-130397 (JP, A) JP-A-6-82784 (JP, A) JP-A-6-148641 (JP, A) (58) Fields studied (Int. Cl. ⁶ , DB Name) G02F 1/1337 G02F 1/13

Claims (13)

(57) [Claims] 1. A first substrate (1) having an alignment film (26).
8), a second substrate (16) facing the first substrate and having an alignment film (22), and a liquid crystal (20) inserted between the first and second substrates. , At least the first
Is composed of a single layer of an alignment material layer having first and second adjacent small regions (A, B), and the single layer of the alignment material layer is composed of the first and second layers. A method for manufacturing a liquid crystal display device, which is continuously rubbed in one direction along two minute regions (A, B), wherein a selection is made in the first and second minute regions (A, B). A method for manufacturing a liquid crystal display device, comprising subjecting a liquid crystal display device to a general modification process. 2. A material layer for changing the hydrophobicity of the alignment film is provided under the alignment film , wherein the material layer is made of amorphous silicon.
The method according to claim 1, characterized in Sodea Rukoto. 3. The liquid crystal display device according to claim 1, wherein the modification process includes a step of selectively heating the first and second minute regions (A, B). Production method. Wherein said heating step, a method of manufacturing a liquid crystal display device according to claim 3, characterized by using one of the infrared heater and laser. Wherein said heating step, claim 3, characterized by using a mask having a portion allowed to transmit heat between the heater and the first substrate and a portion for blocking heat
3. The method for manufacturing a liquid crystal display device according to item 1. 6. The method according to claim 5 , wherein a portion of the mask that transmits heat has a size substantially equal to a half of a pixel pitch. Wherein said heating step is the manufacture of liquid crystal display device according to claim 3, characterized in that use a laser source, a scanning means for selectively scanning the laser beam emitted from the laser source Method. 8. The minute area to be heated of the first and second minute areas (A, B) of the first substrate has a length and a width, and the scanning unit is heated. 8. The liquid crystal display according to claim 7 , wherein the laser beam is scanned in a width direction of the minute area to be heated, and the scanning means is movable in a length direction of the minute area to be heated. Device manufacturing method. 9. A first substrate (1) having an alignment film (26).
8), a second substrate (16) facing the first substrate and having an alignment film (22), and a liquid crystal (20) inserted between the first and second substrates. , At least the first
Is composed of a single layer of an alignment material layer having first and second adjacent small regions (A, B), and the single layer of the alignment material layer is composed of the first and second layers. A method for manufacturing a liquid crystal display device, which is continuously rubbed in one direction along two minute regions (A, B), wherein a selection is made in the first and second minute regions (A, B). A modification process, wherein the modification process selectively changes a concentration distribution of a chemical component that governs a pretilt angle of a surface of the first and second minute regions (A, B). The step of selectively changing the concentration distribution of the chemical component that governs the pretilt angle on the surface of the first and second minute regions (A, B) comprises: A, B)
Forming a material layer for selectively increasing or decreasing the pretilt angle on the surface of the liquid crystal display device. 10. The first and second minute regions (A,
The step of adhering the material layer for selectively increasing or decreasing the pretilt angle to the surface of B) comprises the step of selectively adhering a material layer having a property of orienting the liquid crystal in a direction perpendicular to the substrate surface. The method for manufacturing a liquid crystal display device according to claim 9 . 11. A first substrate (18) having an alignment film (26), and an alignment film (22) opposed to the first substrate.
And a liquid crystal (20) inserted between the first and second substrates, and at least the alignment film (26) of the first substrate has And a single layer of an alignment material layer having a second adjacent minute area (A, B), wherein the single layer of the alignment material layer extends along the first and second minute areas (A, B). A method of manufacturing a liquid crystal display device which is continuously rubbed in one direction, wherein said first and second fine particles are changed so that a solvent volatilization time changes after applying an alignment material to said first substrate. A method for manufacturing a liquid crystal display device, comprising selectively curing regions (A, B). 12. The method of claim 11, wherein the heating Precure step, according to claim 11, characterized by using a mask having a portion allowed to transmit heat between the heater and the first substrate and a portion for blocking heat Of manufacturing a liquid crystal display device. 13. The heating pre-curing step includes heating the first substrate by a heater and selectively cooling the first and second minute regions (A, B). Item 12. The method for manufacturing a liquid crystal display device according to item 11 .