JP2003149645A - Rubbing apparatus and liquid crystal display device manufactured by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubbing apparatus where a defective rubbing does occurs even in the case of performing an oblique rubbing to a liquid crystal substrate where a vertical alignment layer is formed and to provide a liquid crystal display device manufactured by using the rubbing apparatus. SOLUTION: In the rubbing apparatus 10 having a rubbing stage 11 which can be moved and in which the liquid crystal substrate 12 with the alignment layer arranged thereon, and a rubbing roller 13 holding rubbing material on the outer periphery of a cylindrical rotator, the liquid crystal substrate 12 with the edges around the substrate surface tilted by ±1 deg. to ±45 deg. with respect to the vertical direction 14 of its moving direction, is arranged. In the rubbing apparatus 10, the rubbing roller 13 is rotated in the same direction as the moving direction A of the rubbing stage 11 at a position where the liquid crystal substrate 12 is in contact with the rubbing material. Otherwise, a dummy substrate having a side surface on the side of the liquid crystal substrate in contact with two edges to be arranged on the front side of the moving direction of the liquid crystal substrate among the edges and a side surface on the side of a tip including an edge in a direction nearly coincident with the vertical direction of the moving direction is arranged.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a VA (Vertically
The present invention relates to a rubbing device that realizes uniform alignment in an aligned mode and a liquid crystal display device manufactured using the rubbing device.

[0002]

2. Description of the Related Art In a liquid crystal display device (LCD) which is currently widely used as various display devices such as a monitor of a personal computer and a liquid crystal television, liquid crystal materials having positive dielectric anisotropy are mutually used. The so-called TN (Twisted Nematic) mode, which is injected into a homogeneous alignment cell having different 90 ° alignment directions, has been most widely used.

In these TN mode liquid crystal display devices, two polarizing plates are arranged above and below the substrate such that their polarization directions are orthogonal to each other, and a light transmission state (white display) is obtained without applying a voltage to the substrate. A normally white type in which light is blocked (black display) in a voltage applied state is general.

In such a TN mode liquid crystal display device,
It is considered that the liquid crystal molecules in the vicinity of the substrate cannot respond to the electric field even when a voltage is applied, and maintains a homogeneous alignment. Therefore, there is a problem that light leakage occurs even in black display, that is, the contrast is low. Occurs.

On the other hand, a so-called V in which a liquid crystal material having a negative dielectric anisotropy is injected into a homeotropic alignment cell.
In the A-mode liquid crystal display device, liquid crystal molecules are aligned in a direction substantially perpendicular to the surface of the substrate in a state where no voltage is applied, which is a normally black type, so that extremely good black display is possible. In other words, the VA mode liquid crystal display device is a mode that can realize a high contrast display that cannot be achieved by the TN mode liquid crystal display device.

[0006]

The rubbing method, which is a method of aligning liquid crystal molecules, is a method generally used in the above-mentioned TN mode liquid crystal display device.
It is known that it is difficult to use in a mode liquid crystal display device. That is, the homeotropic alignment film (vertical alignment film) material used for the VA mode liquid crystal display device has a pretilt angle manifestation margin with respect to the rubbing condition as compared with the homogeneous alignment film (horizontal alignment film) material used for the TN mode liquid crystal display device. This is because it is narrow, so that a defective alignment is likely to occur due to a slight condition difference in the substrate during rubbing.

FIG. 17 (a) is a plan view showing a schematic structure of a conventional rubbing apparatus, and FIG. 17 (b) is a plan view.
It is sectional drawing seen from the cutting plane line VI-VI of (a). A rubbing apparatus that has been generally used in the past has a liquid crystal substrate 1 mounted on a moving table called a rubbing stage 111.
The rubbing roller 1 is a rotary roller in which 12 is fixed by a vacuum suction or a pressing pin, and a cloth such as cotton or rayon is fixed on the surface while moving it in the direction of arrow A.
13 rotates in the direction of arrow B to rub (rubbing) the surface of the substrate to align the alignment film on the substrate.

FIG. 18 (a) is a plan view showing one construction of the substrate arrangement with respect to the rollers during rubbing. FIG. 18B is a plan view showing another configuration of the substrate arrangement with respect to the rollers during rubbing. FIG. 19A shows
FIG. 19 is a plan view schematically showing the twisting direction of the tips of the rollers, which occurs in the substrate arrangement of FIG. FIG. 19B is a plan view schematically showing the twisting direction of the tips of the rollers generated in the substrate arrangement of FIG. 18B. In FIG. 18A, one side 115 of the liquid crystal substrate 112 is in the moving direction (arrow A direction).
Is placed on the rubbing stage 111 at an angle θ1 of ± 1 ° to ± 45 ° with respect to the vertical direction 114. The case where the rubbing process is performed on the liquid crystal substrate 112 placed at such an angle is referred to as “oblique rubbing” for convenience. In FIG. 18B, one side 11 of the liquid crystal substrate 112.
5 is placed on the rubbing stage 111 so as to be tilted at an angle of 0 to ± 1 ° from the vertical direction 114 of the moving direction (arrow A direction), that is, substantially coincident with the vertical direction 114. The liquid crystal substrate 112 placed at such an angle
The case where the rubbing process is performed on is referred to as "vertical rubbing".

FIG. 20 is a cross-sectional view for explaining a rubbing state caused by rotation of a forward-rotating roller. Figure 20 (a)
18A corresponds to a cross-sectional view taken along the section line VII-VII in FIG. FIG. 20B corresponds to the cross-sectional view taken along the section line VIII-VIII of FIG. The rubbing device 110 is a rubbing device that is generally used when manufacturing a TN mode liquid crystal display device. As shown in FIGS. 20A and 20B, the liquid crystal substrate 112 and a rubbing cloth that is a rubbing material are in contact with each other. At the position 120, the rotation direction of the rubbing roller 113 is set to the facing direction (hereinafter, referred to as “forward rotation”) opposite to the moving direction of the rubbing stage 111.

In the case of vertical rubbing shown in FIG. 18 (b),
Even if the liquid crystal substrate 112 is moved in the direction of arrow A and the rubbing roller 113 is rotated in the forward direction to perform the rubbing process, the edge 119 of the liquid crystal substrate 112 is substantially parallel to the rotation axis of the rubbing roller 113. Rubbing roller 1
The tips of the rubbing cloth fixed on the surface of FIG.
There is no twist in the direction of arrow D shown in (b).

On the other hand, when the oblique rubbing shown in FIG. 18 (a) is performed by forward rotation, a problem occurs depending on the type of the alignment film. As described above, since the horizontal alignment film used in the TN mode liquid crystal display device has a relatively wide margin for showing a stable pretilt with respect to the rubbing condition, there is substantially no problem even if diagonal rubbing is performed in forward rotation. Absent.

However, a problem arises when oblique rubbing is performed by forward rotation on a substrate on which a vertical alignment film having a relatively narrow margin showing a stable pretilt with respect to rubbing conditions is formed. FIG. 21 is an enlarged view showing the vicinity of the position 120 where the rubbing material shown in FIG. In FIG. 21, the rubbing roller 1
Bristles 122 of rubbing cloth 121 fixed to the surface of 13
The state where the edge 118 of the liquid crystal substrate 112 contacts is shown. When oblique rubbing is performed by forward rotation, the liquid crystal substrate 11
It is considered that the bristles 122 of the rubbing cloth 121 twisted by the second edge 118 ride on the liquid crystal substrate 112 as they are to cause rubbing failure. That is, in the case of oblique rubbing, when the liquid crystal substrate 112 is moved in the arrow A direction, the tips 122 of the rubbing cloth 121 fixed to the surface of the rubbing roller 113 are twisted in the arrow C direction shown in FIG. Be done. Specifically, as shown in FIG. 21, the bristle tips 122 of the rubbing cloth 121 are first formed on the liquid crystal substrate 11.
2 corresponds to the edge 118, but since the edge 118 is inclined with respect to the rotation axis of the rubbing roller 113, the bristle tip 122 exerts a force in the x-axis direction that extends horizontally in the left-right direction toward the paper surface. , Arrow C shown in FIG. 19 (a)
Direction, a force is applied in the y-axis direction that extends perpendicularly to the plane of the paper. Therefore, while sliding on the edge 118,
The bristle tips 122 are distorted in the y-axis direction and are obliquely oriented with respect to the moving direction of the liquid crystal substrate 112 or the rotating direction of the rubbing roller 113. The slanted bristles ride on the substrate as they are, thereby producing a rubbing effect having a strength different from that of vertical rubbing. In addition, it is considered that the direction and strength of the twist slightly change depending on the position and time of the rubbing cloth, which causes the orientation failure.

Oblique rubbing as described above is necessary for the following reasons, although it has a problem of causing alignment failure.

FIG. 22 is an isocontrast curve diagram showing an example of viewing angle characteristics in a vertically aligned cell. The viewing angle characteristics are those of a liquid crystal display device (LCD) in which a vertical alignment film material is used and vertical rubbing is performed, and then the rubbing directions of the upper and lower substrates are twisted by 90 ° and laminated. This viewing angle characteristic is not uniform in all directions and has a maximum viewing angle direction. The maximum viewing angle direction is a range in which the contrast, gradation characteristics, and color characteristics of the liquid crystal display device when viewed obliquely from the front are substantially the same as those when viewed from the front, and are within a range that is practically acceptable. The viewing angle indicating the range of the viewing angle is the direction in which the viewing angle becomes maximum. When the viewing angle characteristic has the maximum viewing angle direction, it is necessary to direct the maximum viewing angle direction to a desired direction.

Since the outer shape of the liquid crystal display device is usually rectangular, the vertical direction is the direction when the hands of the clock indicate 12 o'clock and 6 o'clock, and the direction when the hands of the clock indicate 9 o'clock and 3 o'clock. It is necessary that the symmetry of contrast, gradation characteristics, and color characteristics is good in the horizontal direction. By directing the maximum viewing angle direction to the desired direction, the symmetry of these characteristics can be improved and the visibility as a liquid crystal display device can be improved. For example, in the case of a liquid crystal television (TV) used in a general home, it is preferable to bring the maximum viewing angle direction 117 to the left-right direction 116 of the drawing, and a relatively high place such as a monitor used in a public place. It is preferable that the maximum viewing angle direction of the liquid crystal display device placed in 1 is set to the vertical direction.

Since the maximum viewing angle direction is arranged in a desired direction as described above, the movement in the viewing angle direction can be performed by changing the design of the retardation plate or the attaching direction of the polarizing plate. It is most convenient to change the rubbing direction in that a liquid crystal display device having angular characteristics can be manufactured using the same material and device. As for the rubbing direction, in order that the optical characteristics of the liquid crystal display device such as the symmetry of the viewing angle and the grayscale inversion in the up-down direction or the left-right direction exhibit desired characteristics, for example, the symmetry of the viewing angle in the left-right direction is good. Therefore, the black and white reversal direction is designed to be upward or downward. In order to change the rubbing direction, it is necessary to adopt diagonal rubbing.

An object of the present invention is to provide a rubbing device which hardly causes a rubbing failure even when a liquid crystal substrate having a vertical alignment film formed thereon is obliquely rubbed, and a liquid crystal display device manufactured using the rubbing device. .

[0018]

The present invention provides at least the following:
A rubbing device having a rubbing stage in which a liquid crystal substrate on which an alignment film is formed is movable and a roller holding a rubbing material for rubbing the liquid crystal substrate on the outer periphery of a cylindrical rotating body, The liquid crystal substrate is arranged such that the sides around the substrate surface are inclined ± 1 ° to ± 45 ° with respect to the direction perpendicular to the moving direction of the liquid crystal substrate, and the roller at the position where the liquid crystal substrate and the rubbing material come into contact with each other. Rotation direction,
In the rubbing device, the moving direction of the rubbing stage is the same direction.

According to the present invention, since the rotation direction of the roller at the position where the liquid crystal substrate and the rubbing material come into contact with each other is set to be the same as the moving direction of the rubbing stage, the direction perpendicular to the moving direction of the liquid crystal substrate is set. On the other hand, even in the oblique rubbing in which the rubbing process is performed with the side of the liquid crystal substrate surrounding the substrate surface tilted by ± 1 ° to ± 45 °, the tips of the rubbing material directly contact the surface of the liquid crystal substrate and the substrate edge Therefore, the tips of the rubbing material are not twisted obliquely with respect to the moving direction of the liquid crystal substrate, and rubbing failure is unlikely to occur.

Further, according to the present invention, at least a rubbing stage on which a liquid crystal substrate on which an alignment film is formed is movable, and a rubbing member for rubbing the liquid crystal substrate are held on the outer periphery of a cylindrical rotating body. In the rubbing device, the liquid crystal substrate has a side around the substrate surface,
± 1 ° to ± 4 with respect to the direction perpendicular to the moving direction of the liquid crystal substrate
It includes a liquid crystal substrate side surface that is inclined by 5 ° and is in contact with two sides of the sides that are arranged on the front side in the moving direction, and a side that is inclined by 0 to ± 1 ° with respect to the direction perpendicular to the moving direction. The rubbing device is characterized in that a dummy substrate having a tip side surface is arranged.

According to the invention, the side surface of the liquid crystal substrate, which is disposed on the front side in the moving direction of the liquid crystal substrate and is in contact with the two sides forming the substrate surface of the liquid crystal substrate, and the direction perpendicular to the moving direction of the liquid crystal substrate are substantially the same. Since the dummy substrate having the tip side surface including the side in the coincident direction is provided, the tip of the rubbing material, even in the oblique rubbing, is the edge of the dummy substrate set in the direction perpendicular to the moving direction of the liquid crystal substrate. The rubbing treatment can be performed by moving onto the liquid crystal substrate without being twisted and twisted, so that rubbing failure is unlikely to occur.

Further, according to the present invention, the thickness of the dummy substrate is
It is characterized in that it is not less than the thickness of the liquid crystal substrate.

According to the present invention, since the thickness of the dummy substrate is equal to or larger than the thickness of the liquid crystal substrate, the hair tips of the rubbing material on the dummy substrate are not in a state of climbing when moving onto the liquid crystal substrate. , Twisting is less likely to occur.

Further, the present invention is characterized in that the side surface on the tip end side of the dummy substrate is a slope forming an angle of less than 90 ° with a surface of the dummy substrate in contact with the rubbing stage.

According to the present invention, the tip of the dummy substrate on which the hair tips of the rubbing material held by the roller ride is attached to the surface of the dummy substrate which contacts the rubbing stage.
Since the slope, which is a surface inclined at an angle of less than 0 °, is provided, the tips of the rubbing material can be smoothly climbed onto the dummy substrate, and twisting of the tips is less likely to occur.

Further, the present invention is characterized in that the side surface of the dummy substrate on the liquid crystal substrate side is an inverse slope which forms an angle of more than 90 ° and less than 180 ° with a surface of the dummy substrate in contact with the rubbing stage. .

According to the present invention, a surface of the dummy substrate, which is in contact with the liquid crystal substrate, is inclined at an angle of more than 90 ° and less than 180 ° with respect to a surface of the dummy substrate in contact with the rubbing stage. Because there is a certain reverse slope,
It is possible to prevent twisting of the hair tips of the rubbing material mounted on the dummy substrate when the hair tips move to the liquid crystal substrate.

Further, the present invention is characterized in that the maximum width of the dummy substrate in the direction perpendicular to the moving direction of the liquid crystal substrate is not less than the maximum width of the liquid crystal substrate in the direction perpendicular to the moving direction of the liquid crystal substrate.

According to the present invention, the maximum width of the dummy substrate in the direction perpendicular to the moving direction of the liquid crystal substrate is set to be equal to or larger than the maximum width of the liquid crystal substrate in the same direction, so that the roller is twisted after riding on the dummy substrate. Only the hair tips that are not left move to the liquid crystal substrate, and it is possible to prevent the occurrence of twisting when moving to the liquid crystal substrate.

Further, the present invention is characterized in that at least a part of a side surface of the dummy substrate on the liquid crystal substrate side has a riding portion on which the dummy substrate extends over the liquid crystal substrate.

According to the present invention, since the riding portion where the dummy substrate is projected on the liquid crystal substrate is provided on the side surface of the dummy substrate on the liquid crystal substrate side, when the roller shifts from the dummy substrate to the liquid crystal substrate, the bristle tips are It is absolutely impossible to climb on the liquid crystal substrate, and twisting is less likely to occur.

According to the present invention, the side surface of the riding portion is
It is characterized in that the liquid crystal substrate is constituted by only side surfaces each including a side inclined by 0 to ± 1 ° with respect to a moving direction of the liquid crystal substrate and a direction perpendicular to the moving direction.

According to the present invention, since the riding portion is constituted by only the side surface including the side in the direction substantially coincident with the moving direction of the liquid crystal substrate and the direction perpendicular thereto, the side where the dummy substrate and the liquid crystal substrate are in contact with each other. Is not inclined with respect to the moving direction of the liquid crystal substrate, and it is possible to prevent the tip of the hair from being twisted when the roller moves from the dummy substrate to the liquid crystal substrate.

Further, in the invention, in the side surface of the riding portion, 0 to ± is set with respect to a direction perpendicular to the moving direction of the liquid crystal substrate.
The side surface including the side inclined by 1 ° is an inverse slope forming an angle of more than 90 ° and less than 180 ° with the surface of the riding portion contacting the liquid crystal substrate.

According to the present invention, in the riding portion, the side surface including the side in the direction substantially coincident with the vertical direction of the moving direction of the liquid crystal substrate has an inverse slope, so that the hair of the rubbing material riding on the dummy substrate is formed. When the tip moves to the liquid crystal substrate,
It is possible to prevent twisting of the hair tips.

Further, according to the present invention, the side surface of the dummy substrate on the liquid crystal substrate side includes only a side surface which is inclined by 0 to ± 1 ° with respect to a moving direction of the liquid crystal substrate and a direction perpendicular to the moving direction. It is characterized by being constituted by.

According to the present invention, the side surface of the dummy substrate on the liquid crystal substrate side is composed only of side surfaces including sides in directions substantially corresponding to a moving direction of the liquid crystal substrate and a direction perpendicular to the moving direction. Therefore, the side where the dummy substrate and the liquid crystal substrate are in contact is not inclined with respect to the moving direction of the liquid crystal substrate, and twisting of the tips of the rubbing material occurs when the roller moves from the dummy substrate to the liquid crystal substrate. Can be further prevented.

Further, the present invention is characterized in that a film made of metal or polymer is fixed on the dummy substrate, and the film is arranged so as to cover a part of the liquid crystal substrate.

According to the present invention, since the metal thin film or the polymer film is fixed on the dummy substrate so as to cover a part of the liquid crystal substrate, the riding portion provided as a part of the dummy substrate is commercially available as described above. Thin films of metals (stainless steel, nickel, aluminum, etc.) and polymers (polyester, polyimide, polyethylene terephthalate (PE
(T) or the like), and can be configured simply by fixing it on a dummy substrate using a film, and the dummy substrate can be easily manufactured at low cost.

In the present invention, the film has a thickness of 10
˜200 μm, and the total thickness of the film and the dummy substrate is equal to or more than the thickness of the liquid crystal substrate.

According to the invention, the thickness of the film is from 10 to 10.
When the thickness is less than 10 μm, the film itself becomes difficult to handle when the thickness is less than 10 μm, and the tip of the roller is pressed more than necessary at a portion where the film and the liquid crystal substrate are overlapped with each other to exceed 200 μm to shorten the life of the rubbing material. There is no problem with the handling of the film or the rubbing device. In addition, since the total thickness of the film and the thickness of the dummy substrate is equal to or greater than the thickness of the liquid crystal substrate, the tips of the rollers riding on the dummy substrate will not be in a state of climbing when moving to the liquid crystal substrate, and will not twist. Is less likely to occur.

Further, the present invention is characterized in that the dummy substrate is provided as a protrusion on the rubbing stage.

According to the present invention, since the dummy substrate is provided as a protrusion on the rubbing stage, for example, when a large amount of liquid crystal substrates are subjected to rubbing treatment by oblique rubbing at the same angle, the liquid crystal substrate is surely provided at the same angle. It is possible to perform rubbing treatment.

According to the present invention, at least a rubbing stage on which a liquid crystal substrate on which an alignment film is formed is movable, and a rubbing material for rubbing the liquid crystal substrate are held on the outer circumference of a cylindrical rotating body. A rubbing device including: a display unit, which is a display area of the liquid crystal display device, is provided on the liquid crystal substrate, and the four sides around the display unit are ± 1 with respect to the four sides around the substrate surface of the liquid crystal substrate. The liquid crystal substrate is disposed at an angle of ± 45 °, and the liquid crystal substrate is disposed on the rubbing stage with one side inclined at 0 ° ± 1 ° with respect to a direction perpendicular to the moving direction of the liquid crystal substrate. It is a rubbing device.

According to the present invention, the display area serving as the display area of the liquid crystal display device is arranged such that the four sides around the display section are inclined by ± 1 ° to ± 45 ° with respect to the four sides around the substrate surface of the liquid crystal substrate. Since it is configured on the liquid crystal substrate and one side of the liquid crystal substrate is arranged so as to be substantially aligned with the direction perpendicular to the moving direction of the liquid crystal substrate,
The liquid crystal substrate itself is subjected to a rubbing treatment as in the case of vertical rubbing so that the hair tips on the surface of the roller are not twisted, and the rubbing treatment can be performed by oblique rubbing in the display section.

Further, the present invention is characterized in that the alignment film formed on the liquid crystal substrate is a homeotropic alignment film.

According to the invention, in the rubbing apparatus, since the alignment film of the liquid crystal substrate is formed of the homeotropic alignment film, the arrangement of the retardation plate and the polarizing plate and the viewing angle characteristics associated therewith are required. Even with a homeotropic alignment film where the rubbing direction is regulated and alignment with the substrate layout, where the rubbing process can be performed uniformly, is difficult to achieve, rubbing rubbing is not performed due to twisting of the tips of the roller surfaces, and alignment is performed by diagonal rubbing. It is possible to take.

The present invention is also a liquid crystal display device comprising a pair of substrates on which at least an electrode and an alignment film are formed, and at least one of the pair of substrates is manufactured using the rubbing device. And a liquid crystal display device.

According to the present invention, since the liquid crystal substrate manufactured by the rubbing device is used, it is possible to provide a liquid crystal display device with uniform alignment.

The present invention is also characterized in that, between the pair of substrates, the rubbing direction of one substrate is twisted by approximately 90 ° with respect to the rubbing direction of the other substrate.

According to the invention, in the liquid crystal display device, the rubbing treatment is performed so that the rubbing direction of the pair of substrates is twisted by about 90 °. Therefore, the arrangement of the retardation plate and the polarizing plate and the associated visual field. The rubbing direction is particularly specified due to the requirement of angular characteristics, and the rubbing process is likely to be inconsistent with the substrate arrangement, which is 90 °.
Even in the rubbing direction with the twist, it is possible to perform the alignment by performing the oblique rubbing without causing the rubbing failure due to the twist of the hair tips on the roller surface.

In the present invention, the liquid crystal material filled between the pair of substrates contains a chiral component, and the ratio (d) between the width (d) between the pair of substrates and the twist pitch (p) of the liquid crystal material.
/ P) is adjusted between 0.2 and 0.35.

According to the present invention, the liquid crystal material contains a chiral component so that the d / p is 0.2 to 0.35. Therefore, for example, a liquid crystal material containing no chiral component is used and the d / p is 0. It is possible to manufacture a liquid crystal display device in which a rubbing failure is less likely to occur as compared with the case where the value is not 2 to 0.35.

[0054]

1 is a plan view showing a schematic structure of a rubbing apparatus according to a first embodiment of the present invention. Figure 2
[FIG. 2] is a cross-sectional view taken along the section line I-I of FIG. 1. The rubbing device 10 includes a rubbing stage 11 and a rubbing roller 13. A rubbing cloth is fixed to the surface of the rubbing roller 13. On the rubbing stage 11, the liquid crystal substrate 12 on which the alignment film is formed,
The liquid crystal substrate 1 whose one side 15 around the substrate surface is indicated by an arrow A
2 from the vertical direction 14 of the moving direction θ1 (± 1 ° to ± 45
It is placed at an angle of only °) and is fixed by vacuum suction or a pressing pin. The rotation direction of the rubbing roller 13 is
At the position where the liquid crystal substrate 12 and the rubbing cloth, which is the rubbing material, come in contact with each other, the arrow E direction is set to be the same direction as the moving direction of the rubbing stage 11 (arrow A direction). The rotation direction of the rubbing roller 13 is called "reverse rotation".

The liquid crystal substrate 12 is θ1 (± 1 ° to ± 45 °).
While the rubbing stage 11 fixed by is moved in the arrow A direction, the rubbing roller 13 rotates in the arrow E direction, so that the alignment film on the liquid crystal substrate 12 is subjected to oblique rubbing rubbing treatment.

In such a reverse rotation, as shown in FIG. 2, the hair tips of the rubbing material come into direct contact with the surface of the liquid crystal substrate 12 and are not affected by the substrate edge 18. In addition, the tips of the hairs are not twisted, and orientation failure due to rubbing failure is unlikely to occur.

The rubbing apparatus according to the first embodiment will be described below with reference to examples and comparative examples.

Example 1 A transparent electrode made of ITO (indium tin oxide) in the form of stripes was formed on a glass substrate, and a vertical alignment film material (JALS-682 manufactured by JSR) was applied and baked on the transparent electrode. The liquid crystal substrate 12 on which the alignment film was fired was placed on the rubbing stage 11 in the rubbing device 10 as shown in FIG. 1 so that θ1 was 45 °.

Then, a rubbing cloth (YA-made by Yoshikawa Kako Co., Ltd.)
The rubbing treatment was performed on the liquid crystal substrate 12 by reversely rotating the rubbing roller 13 having the surface 19R) fixed on the surface in the arrow E direction. The rubbing direction at this time is oblique rubbing. As for the counter substrate of the liquid crystal substrate 12, the alignment film is baked in the same manner as the liquid crystal substrate 12, and when the liquid crystal substrate 12 and the stripe-shaped transparent electrodes are laminated so as to be orthogonal to each other, as will be described later, they are mutually bonded. The rubbing treatment was performed so that the rubbing directions also intersect (orthogonal) at 90 °. Therefore, diagonal rubbing is also performed on the counter substrate. For the liquid crystal substrate 12 and the counter substrate, the pushing amount of the rubbing cloth is 0.2, 0.4, 0.6, respectively.
It was set to 0.8 mm and subjected to four kinds of rubbing treatments.

Here, the pushing amount of the bristle tip refers to the length of the portion of the bristle tip of the rubbing cloth that is pressed against the liquid crystal substrate 12 during the rubbing process. FIG. 3 is a sectional view schematically showing a state where the liquid crystal substrate 12 and the rubbing cloth 19 are in contact with each other. The cross-sectional view corresponds to the cross-sectional view taken along the section line II of FIG. The hair tip pressing amount dx is dc, which is the total thickness of the rubbing cloth 19 including the hair tips, and ds is the thickness of the liquid crystal substrate 12 that is subjected to the rubbing treatment, and the hair tips of the rubbing cloth and the liquid crystal substrate 12 are in contact with each other. When the distance from the surface of the rubbing stage 11 facing the rubbing roller 13 to the surface of the rubbing roller 13 at the position
It is represented by the following formula (1). dx = (dc + ds) -t (1)

Next, the striped transparent electrodes of the liquid crystal substrate 12 and the counter substrate, which have been subjected to the rubbing treatment with the same amount of pushing the tips of the electrodes, are orthogonal to each other via the spacer beads (Micropearl manufactured by Sekisui Chemical Co., Ltd.), Moreover, they were laminated so that their rubbing directions intersect at 90 °. A liquid crystal display device was manufactured by injecting a liquid crystal material having a negative dielectric anisotropy between the bonded liquid crystal substrate 12 and the counter substrate.

Comparative Example 1 An alignment film was baked on a glass substrate in exactly the same manner as in Example 1. The liquid crystal substrate 112 having the alignment film fired thereon is provided with a rubbing apparatus having exactly the same configuration as the rubbing apparatus 10 shown in FIG. 1 except that the rubbing roller 113 is normally rotated. The rubbing roller 113 is placed at 45 °, and as shown in FIG.
Is rotated in the direction of arrow B, the liquid crystal substrate 1
Rubbing treatment was performed on 12. This liquid crystal substrate 11
As for the counter substrate of No. 2 as well, the alignment film is baked in the same manner as the liquid crystal substrate 112, and when it is bonded to the liquid crystal substrate 112, the rubbing process is performed so that the rubbing directions intersect each other at 90 °, and the alignment substrate is completely different from that of Example 1. A liquid crystal display device was produced in the same manner by laminating.

Comparative Example 2 A rubbing apparatus 10 shown in FIG. 1 was used for a liquid crystal substrate 12 in which an alignment film was fired on a glass substrate in exactly the same manner as in Example 1.
The rubbing device having the same structure as the above was placed so that θ1 was approximately 0 °, that is, one side of the liquid crystal substrate 12 was substantially perpendicular to the moving direction of the liquid crystal substrate 12 (direction of arrow A). The rubbing treatment was performed on the liquid crystal substrate 12 by rotating the rubbing roller 13 in the direction of arrow E in the same manner as in Example 1. The rubbing direction at this time is vertical rubbing. As for the counter substrate of the liquid crystal substrate 12, an alignment film was baked in the same manner as the liquid crystal substrate 12 and, when the liquid crystal substrate 12 was bonded, a rubbing treatment was performed so that the rubbing directions intersect each other at 90 °. Therefore, vertical rubbing is also performed on the counter substrate.

Then, the liquid crystal substrate 12 subjected to rubbing treatment by vertical rubbing and the counter substrate were laminated in the same manner as in Example 1 to fabricate a liquid crystal display device.

Comparative Example 3 The rubbing apparatus 10 shown in FIG. 1 was used, except that the rubbing roller 113 was rotated in the same manner as in the liquid crystal substrate 112 in which the alignment film was baked on the glass substrate in exactly the same manner as in Example 1. The rubbing device having exactly the same configuration was mounted so that θ1 was approximately 0 °. As shown in FIG. 20A, the rubbing roller 113 was sequentially rotated in the direction of arrow B to rub the liquid crystal substrate 112 by vertical rubbing. As for the counter substrate of the liquid crystal substrate 112, when the alignment film is baked similarly to the liquid crystal substrate 112 and the liquid crystal substrate 112 is bonded to the alignment film, the rubbing directions thereof are 90 °.
Rubbing treatment is applied by vertical rubbing so that it intersects with,
A liquid crystal display device was produced by laminating the substrates in exactly the same manner as in Example 1.

Comparative Examples 4 to 7 A transparent electrode made of ITO in a stripe pattern was formed on a glass substrate, and a horizontal alignment film material (AL-produced by JSR Corporation) was formed on the transparent electrode.
Liquid crystal display devices of Comparative Examples 4 to 7 were respectively manufactured in exactly the same manner as in Example 1 and Comparative Examples 1 to 3 except that 4552) was applied and baked.

Regarding the liquid crystal display devices of Example 1 and Comparative Examples 1 to 7, a rubbing cloth (YA-made by Yoshikawa Kako Co., Ltd.) was used.
Table 1 shows the orientation state of each of the hair tips of 19R).

[0068]

[Table 1]

From Table 1, when the liquid crystal display device of Example 1 is observed under crossed Nicols, the pushing amount of the tip of the hair is 0.4, 0.
At 6, 0.8 mm, the rubbing effect was strong and scratches were observed on the alignment film at 0.8 mm, but good uniform alignment was obtained and almost uniform rubbing treatment was performed over the entire surface of the substrate. I understood. When the liquid crystal display device of Comparative Example 1 is observed under crossed Nicols, the push-in amount of the hair tips is 0.2, 0.4,
In both cases of 0.6 and 0.8 mm, streak-like unevenness was observed in the rubbing direction, and it was found that the rubbing treatment was performed nonuniformly. Therefore, even when obliquely rubbing a homeotropic alignment (vertical alignment film) cell in which misalignment is likely to occur, by adopting the reverse rotation rubbing, it is possible to provide a rubbing device that can obtain uniform alignment, and thus a uniformly aligned VA mode liquid crystal. A display device can be manufactured.

FIG. 4 is a block diagram showing a schematic structure of the rubbing apparatus according to the second embodiment of the present invention. Figure 4 (a)
[Fig. 4] is a plan view showing a schematic configuration of a rubbing apparatus of the second embodiment, and Fig. 4 (b) is a sectional line II- of Fig. 4 (a).
It is sectional drawing seen from II. FIG. 5 is a cross-sectional view schematically showing a rubbing process performed by the rubbing apparatus shown in FIG. The cross-sectional view is taken along the section line II-II in FIG.
It corresponds to the cross-sectional view seen from above. The rubbing device of this embodiment includes a rubbing stage 21, a dummy substrate 27, and a rubbing roller 23. A rubbing cloth 190 is fixed to the surface of the rubbing roller 23.
On the rubbing stage 21, the liquid crystal substrate 22 on which the alignment film is formed is separated by θ1 (± 1 from the vertical direction 24 of the moving direction of the liquid crystal substrate 22 in which one side 25 around the substrate surface is indicated by an arrow A.
It is arranged by tilting (° to ± 45 °) and is fixed by vacuum suction or a pressing pin. At this time, the liquid crystal substrate 22
Is a square or rectangle and the four corners are right angles, so all four sides around the board surface are ± 1 ° to ± 45 ° from the vertical direction 24.
Only tilted and fixed. Further, on the rubbing stage 21, a side inclined by 0 to ± 1 ° with respect to the vertical direction 24, that is, a side in a direction substantially matching the vertical direction 24,
One side 25 arranged on the front side in the moving direction of the liquid crystal substrate 22.
Or two dummy substrates 2 having sides that contact 26
7 is fixed. The thickness of the dummy substrate 27 is set to be not less than the thickness ds of the liquid crystal substrate 22 and not more than the sum (ds + dc) of the thickness ds of the liquid crystal substrate 22 and the total thickness dc of the rubbing cloth 190 including the tips 191. The rotation direction of the rubbing roller 23 is set so as to rotate forward in the arrow B direction.

The liquid crystal substrate 22 is θ1 (± 1 ° to ± 45 °).
The two sides 25 of the liquid crystal substrate 22 are fixed while being inclined.
And the rubbing stage 21 fixed to the dummy substrate 27 in contact with 26 are rotated in the direction of arrow A, and the rubbing roller 23 is rotated in the direction of arrow B, so that the alignment film on the liquid crystal substrate 22 is rubbed by oblique rubbing. Processing is performed.

By providing the dummy substrate 27 as described above, the hair tips 191 of the rubbing cloth 190 fixed to the surface of the rubbing roller 23 are moved in the moving direction of the liquid crystal substrate 22 before being mounted on the liquid crystal substrate 22. The dummy substrate 2 having a side in a direction substantially corresponding to the vertical direction 24 of the arrow A direction
Since it gets on 7 and moves to the liquid crystal substrate 22 as it is,
As in the case of vertical rubbing, the hair tips do not twist.

As described above, the thickness of the dummy substrate 27 is equal to or greater than the thickness ds of the liquid crystal substrate 22, the sum of the thickness ds of the liquid crystal substrate 22 and the total thickness dc of the rubbing cloth 190 including the tips 191 ( ds + dc) or less.
As a result, the bristle tips 19 mounted on the dummy substrate 27
1 is a liquid crystal substrate 22 having a thickness equal to or less than the thickness of the dummy substrate 27.
Since it slides on the top, it does not ride up when the dummy substrate 27 is transferred onto the liquid crystal substrate 22, and the hair tips 191 are not twisted. That is, by setting the thickness of the dummy substrate 27 within the above range, twisting of the tips of the hairs is less likely to occur, so that alignment failure due to rubbing failure can be prevented. Further, the rubbing roller 23 can be prevented from being damaged.

In the rubbing apparatus of the second embodiment, the dummy substrate is fixedly provided on the rubbing stage, but a protrusion having the same shape as the dummy substrate may be previously provided on the rubbing stage. . If a dummy substrate like the former is used, diagonal rubbing can be easily changed to an arbitrary angle for each rubbing process, and if a dummy substrate like the latter is used, for example, a large amount of liquid crystal substrates can be rubbed by diagonal rubbing at the same angle. It is possible to reliably perform the rubbing treatment at the same angle in the case of performing.

FIG. 6A is a plan view showing the structure of a second example of the rubbing stage used in the rubbing apparatus of the second embodiment. FIG. 6B is a sectional line II of FIG.
It is sectional drawing seen from I-III. FIG. 7 is a plan view for explaining the size relationship between the liquid crystal substrate 22 and the dummy substrate 28 on the rubbing stage 31 of FIG. Similar to the rubbing stage 21 shown in FIG. 4, the liquid crystal substrate 22 is arranged on the rubbing stage 31 from the vertical direction 24 of the moving direction of the liquid crystal substrate 22 whose one side 25 constituting the substrate surface side is indicated by an arrow A. It is fixed at an angle of θ1 (± 1 ° to ± 45 °). On the rubbing stage 31 of the second example, a side inclined by 0 to ± 1 ° with respect to the vertical direction 24 and two sides arranged on the front side in the arrow A direction which is the moving direction of the liquid crystal substrate 22. A dummy substrate 28 having a side in contact with sides 25 and 26 is fixed. Specifically, the maximum width 29 of the dummy substrate in the vertical direction 24 of the moving direction of the liquid crystal substrate 22 (arrow A direction) is fixed to be the maximum width 30 of the liquid crystal substrate 22 in the vertical direction 24 or more. The thickness of the dummy substrate 28 is the same as that of the dummy substrate 27.
Of the liquid crystal substrate 22 and the total thickness dc of the rubbing cloth including the tips of the rubbing cloth (ds + dc) or less.

By providing such a dummy substrate 28, the tips of the rubbing cloth fixed on the surface of the rubbing roller 23 are in the direction of movement of the liquid crystal substrate 22 before being mounted on the liquid crystal substrate 22. The liquid crystal substrate 22 having a thickness equal to or smaller than the thickness of the dummy substrate 28 is mounted on the dummy substrate 28 having a side in a direction substantially corresponding to the vertical direction 24 of the mark A direction.
Since it slides on the top, the hair tips are not twisted as in the case where vertical rubbing or the dummy substrate 27 is provided. The width 29 of the dummy substrate 28 on which the tips of the rubbing rollers 23 ride
However, since the maximum width of the liquid crystal substrate 22 is 30 or more, only the tip of the hair that is not twisted after riding on the dummy substrate 28 slides on the liquid crystal substrate 22, and twist is generated on the liquid crystal substrate 22. Never.

FIG. 8 is a sectional view showing the structure of an example in which the tip side of the dummy substrate is modified. The cross-sectional view corresponds to the cross-sectional view taken along the section line III-III in FIG. The dummy substrate 32 used in the rubbing apparatus of the second embodiment and provided on the rubbing stage 31 is 0 to ± 1 ° with respect to the vertical direction of the moving direction (arrow A direction) of the liquid crystal substrate.
The tip side surface 32b including the inclined side, that is, the side in the substantially same direction as the vertical direction is the rubbing stage 3 of the dummy substrate 32.
It may be a slope forming an angle θ2 of 1 ° to less than 90 ° with the surface 32a in contact with 1. Here, the slope is a surface inclined at an angle of less than 90 ° with respect to a certain surface. Since the tip side surface 32b is a slope, the length d1 of the surface 32a of the dummy substrate 32 in contact with the rubbing stage 31 in the moving direction of the rubbing stage 31 indicated by the arrow A is equal to that of the surface 32c facing the surface 32a. It becomes longer than the length d2 in the moving direction (d1> d2)
Is configured as follows. This slope is used for the dummy substrate 3
By providing it on the tip side of the moving direction of 2, the bristles of the rubbing material can smoothly climb on the dummy substrate 32. That is, since the tip of the bristle does not rise abruptly, twisting of the tip of the rubbing material is less likely to occur.

FIG. 9 is a sectional view showing the structure of the first example in which the liquid crystal substrate side of the dummy substrate is modified. The cross-sectional view corresponds to the cross-sectional view taken along the section line III-III in FIG. Used in the rubbing apparatus of the second embodiment,
Dummy substrate 33 provided on the rubbing stage 31
Is the rubbing stage 31 of the dummy substrate 33 when the two liquid crystal substrate side surfaces 33 d contacting the two sides inclined by ± 1 ° to ± 45 ° with respect to the vertical direction of the moving direction of the liquid crystal substrate (arrow A direction). It may be a reverse slope that forms an angle θ3 (90 ° <θ3 <180 °) of more than 90 ° and less than 180 ° with the surface 33a in contact with. Here, the reverse slope is a surface inclined at an angle of more than 90 ° and less than 180 ° with respect to a certain surface. Since the side surface 33d on the liquid crystal substrate side has an inverse slope, the rubbing stage 3 of the dummy substrate 33 is
The length t1 of the surface 33a in contact with 1 in the moving direction of the rubbing stage 31 indicated by the arrow A is shorter than the length t2 of the surface 33c facing the surface 33a in the moving direction (t1 <t2). Is composed of. By providing such a reverse slope on the liquid crystal substrate side of the dummy substrate 33, the tips of the rubbing material move from the dummy substrate 33 to the liquid crystal substrate 2.
It is possible to prevent the twisting of the bristle tips from occurring when shifting to the upper part.

FIG. 10A is a sectional view showing the configuration of the second example in which the liquid crystal substrate side of the dummy substrate is modified. The cross-sectional view corresponds to the cross-sectional view taken along the section line III-III in FIG. The dummy substrate 34 used in the rubbing apparatus of the second embodiment and provided on the rubbing stage 31 is ± 1 ° to ± 45 ° with respect to the vertical direction of the moving direction (arrow A direction) of the liquid crystal substrate 22. A riding portion 35, in which the dummy substrate 34 extends over the liquid crystal substrate 22, may be formed on at least a part of the two liquid crystal substrate side surfaces that are in contact with the two inclined sides. As a result, when the rubbing roller is moved from the dummy substrate 34 to the liquid crystal substrate 22, the tips of the hairs are never allowed to ride on the liquid crystal substrate 22, so that the twist is less likely to occur.

FIG. 10B is a sectional view showing another structure of the riding portion 35 of FIG. 10A. Dummy substrate 39
A film 40 made of a metal or polymer, which is different from the dummy substrate 39, is fixed on the upper portion of the dummy substrate 39 to form a riding portion 35 having the same shape as the dummy substrate 34 of FIG. As the material of the film 40, stainless steel, nickel, aluminum or the like can be used in the case of a metal thin film, and in the case of a polymer film,
Polyester, polyimide, PET or the like can be used. Specific examples of the polymer film include a commercially available polyester film (Tough Top manufactured by Toray) and a polyimide film (Kapton manufactured by DuPont Toray).

According to such a structure, it is not necessary to form a ride-on portion on the dummy substrate, and the ride-on portion can be easily and cheaply provided to manufacture the dummy substrate, and the rubbing apparatus can be provided at a lower cost. be able to.

The thickness of the film 40 is 10 to 20.
It is preferably 0 μm. If the thickness is less than 10 μm, it becomes difficult to handle the film itself, and if the thickness exceeds 200 μm, the tips of the rollers are pressed more than necessary at the overlapping portion of the film and the liquid crystal substrate, and the life of the rubbing material is shortened.

FIG. 11A is a plan view showing the configuration of the third example in which the liquid crystal substrate side of the dummy substrate is modified. Figure 11
FIG. 11B is an enlarged view showing an enlarged part of the configuration of the contact portion between the dummy substrate and the liquid crystal substrate of FIG. 11A. Figure 1
2 is a sectional view taken along the section line IV-IV in FIG. The dummy substrate 37 used in the rubbing apparatus of the second embodiment and provided on the rubbing stage 31 is ± 1 ° to ± 45 ° with respect to the vertical direction 24 of the moving direction (arrow A direction) of the liquid crystal substrate 22. The side formed by the two liquid crystal substrate side surfaces 38b that contact the two inclined sides and the surface 38c that does not contact the rubbing stage 31 indicates the direction of arrow A, which is the direction of movement of the liquid crystal substrate 22, and the direction of movement. It has a staircase shape composed of only sides inclined by 0 to ± 1 ° with respect to the vertical direction 24. That is, the liquid crystal substrate side surface 38b is 0 to the arrow A direction which is the moving direction of the liquid crystal substrate 22 and the vertical direction 24 of the moving direction.
It is composed of only side faces including sides that are inclined ± 1 °. In addition, the staircase-shaped portion forms a riding portion 38 that extends over the liquid crystal substrate 22 in at least a part of the dummy substrate 37. Further, in the riding portion 38, a liquid crystal substrate side surface 38b including a side inclined by 0 to ± 1 ° with respect to the vertical direction 24 of the moving direction of the liquid crystal substrate 22 is a surface 38a of the riding portion 38 in contact with the liquid crystal substrate 22. And the reverse slope forms an angle θ4 (90 ° <θ4 <180 °) of more than 90 ° and less than 180 °. That is, the rubbing stage 3 indicated by the arrow A on the surface 38a of the riding portion 38 in contact with the liquid crystal substrate 22.
The length s1 in the moving direction of 1 is shorter than the length s2 in the moving direction of the surface 38c facing the surface 38a (s1.
<S2).

Since the side in which the dummy substrate 37 and the liquid crystal substrate 22 are in contact is not inclined with respect to the arrow A direction which is the moving direction of the liquid crystal substrate 22 due to the step shape, the tips of the rubbing materials are twisted. There is no. In addition, since the liquid crystal substrate side surface 38b of the riding portion 38 formed by the stepped portion has an inverse slope, when the rubbing roller moves from the dummy substrate 37 to the liquid crystal substrate 22, the tip of the rubbing material is removed. It is possible to further prevent the occurrence of twist.

The slope or deformation provided on the tip side surface or the liquid crystal substrate side surface of the dummy substrate as described above is caused by the dummy substrate fixedly provided on the rubbing stage and the projection on the rubbing stage, as described above. It can be set on any of the dummy substrates provided in advance.

FIG. 13A is a plan view showing the structure of a third example of the rubbing stage used in the rubbing apparatus of the second embodiment. FIG. 13B is a sectional view taken along the section line V-V in FIG. The rubbing stage 41 used in the rubbing apparatus of the second embodiment has a liquid crystal substrate 22 on its surface, and a side 25 of the liquid crystal substrate 22 from a vertical direction 24 of the moving direction of the liquid crystal substrate 22 indicated by an arrow A to θ1 (± 1
The surface of the rubbing stage 41 and the surface of the liquid crystal substrate 22 are buried in a state of being inclined by (° to ± 45 °).

By eliminating the step between the rubbing stage 41 and the liquid crystal substrate 22 as described above, the tip of the rubbing roller is not twisted by the step even when oblique rubbing is performed.

As described above, the rubbing apparatus according to the second embodiment can have any of the configurations shown in FIGS. 4 to 13, but it is particularly preferable to have the configuration shown in FIG. .

FIG. 14 is a block diagram showing a schematic structure of the rubbing apparatus according to the third embodiment of the present invention. The rubbing device includes a rubbing stage 51 and a rubbing roller 5.
3 is included. On the rubbing stage 51,
The liquid crystal substrate 52 has a liquid crystal substrate 5 whose one side is indicated by an arrow A.
It is placed so as to be inclined at an angle of 0 to ± 1 ° from the vertical direction 54 of the moving direction of 2, that is, substantially aligned with the vertical direction 54. The rotation direction of the rubbing roller 53 is set to a forward rotation that is opposite to the moving direction (arrow A direction) of the rubbing stage 51 at the position where the liquid crystal substrate 52 and the rubbing material on the surface of the rubbing roller 53 contact each other. .

FIG. 15 is a plan view showing an example of the arrangement of the liquid crystal display section on the liquid crystal substrate 52 mounted on the rubbing apparatus of FIG. The liquid crystal substrate 52 includes an electrode and an orientation control layer, and includes one panel of a liquid crystal display section 56 which serves as a display area of a liquid crystal display device. The liquid crystal display 56 is
The liquid crystal substrate 52 is arranged on the liquid crystal substrate 52 with its four sides inclined by θ5 (± 1 ° to ± 45 °) with respect to the four sides around the substrate surface of the liquid crystal substrate 52.

Since the liquid crystal substrate 52 on which the liquid crystal display section 56 is formed in such an arrangement is placed on the rubbing apparatus as shown in FIG. 14, the liquid crystal substrate 52 itself is rubbed as in the case of vertical rubbing. The bristles of the rubbing cloth fixed on the surface of the rubbing roller 53 are not twisted after the treatment, and the rubbing treatment (oblique rubbing) can be performed in any direction in the liquid crystal display unit 56.

Such a rubbing device is useful when the orientation control layer is composed of a homeotropic alignment film, and further, the orientation control layer is composed of a homeotropic alignment film,
Further, it is extremely useful between the pair of substrates when the rubbing direction of one substrate is twisted by approximately 90 ° with respect to the rubbing direction of the other substrate. This is the so-called ECB (Electrically Controlled Birefringenc)
Compared to a liquid crystal display device in which the rubbing directions of the upper and lower substrates are parallel or anti-parallel as in the e) mode, a liquid crystal display device in which the rubbing directions of the upper and lower substrates are twisted by 90 ° is a liquid crystal due to the arrangement of a retardation plate or a polarizing plate. This is because the rubbing direction of the display unit is often defined. That is, the rubbing direction of the liquid crystal display part is regulated due to the requirements of the retardation plate and the polarizing plate and the viewing angle characteristics associated therewith, and the rubbing process may not be consistent with the arrangement of the liquid crystal substrate. In such a case, the rubbing apparatus adopts the liquid crystal substrate 52 of the third embodiment as a measure for matching the rubbing direction of the liquid crystal display unit with the arrangement of the liquid crystal substrate.

FIG. 16 is a plan view showing another example of the arrangement of the liquid crystal display section on the liquid crystal substrate 62 mounted on the rubbing apparatus of FIG. The liquid crystal substrate 62 includes five panels of liquid crystal display portions 66 on which electrodes and alignment control layers are formed. These liquid crystal display portions 66 have their four sides surrounded by θ6 (± 1) with respect to the four sides around the substrate surface of the liquid crystal substrate 62.
It is arranged on the liquid crystal substrate 62 with an inclination of (° to ± 45 °).

By mounting the liquid crystal substrate 62 on which the plurality of liquid crystal display portions 66 are formed in such an arrangement on the rubbing apparatus as shown in FIG. 14, the liquid crystal substrate 62 itself is different from the case of vertical rubbing. Similarly, the rubbing process is performed, and the rubbing process can be performed by oblique rubbing in each liquid crystal display unit 66 without twisting the tips of the rubbing cloth fixed to the surface of the rubbing roller 53.

Although the rubbing apparatus of the third embodiment described above has a structure in which no dummy substrate is provided, as in the rubbing apparatus of the first embodiment, the rubbing apparatus of the third embodiment is the first rubbing apparatus. Since it is easier to mount the liquid crystal substrate than the rubbing apparatus of the embodiment, it is more preferable to adopt the configuration of the third embodiment when the dummy substrate is not provided.

The rubbing apparatus according to the second and third embodiments will be described below with reference to examples and comparative examples.

Example 11 A transparent electrode made of ITO in a stripe pattern was formed on a glass substrate, and a vertical alignment film material (JAL manufactured by JAL) was formed on the transparent electrode.
S-682) was applied and fired. The liquid crystal substrate 22 on which the alignment film is fired is placed on the rubbing stage 21 so that θ1 is 45 ° in the rubbing device as shown in FIG. 4A, and the dummy substrate 27 is placed on the rubbing stage 21. One side is the vertical direction 24 of the moving direction of the rubbing stage 21.
It is arranged so that it substantially matches with. This dummy substrate 27 is
About 0.1 than the glass substrate used as the liquid crystal substrate 22.
The thing thicker than mm was used.

Then, the rubbing roller 23 is moved to the position shown in FIG.
The liquid crystal substrate 22 was rubbed by rotating it in the direction of arrow B shown in FIG. This liquid crystal substrate 2
Regarding the counter substrate 2 as well, the alignment film is baked in the same manner as the liquid crystal substrate 22, and when the liquid crystal substrate 22 and the striped transparent electrodes are laminated so as to be orthogonal to each other, as will be described later,
The rubbing treatment was performed by oblique rubbing so that the rubbing directions intersect (orthogonal) at 90 °.

Next, the stripe-shaped transparent electrodes of the liquid crystal substrate 22 subjected to the alignment treatment and the counter substrate are orthogonal to each other via the spacer beads (Micropearl manufactured by Sekisui Chemical Co., Ltd.), and the rubbing directions of the electrodes are also mutually orthogonal. Laminated so that they intersect at 90 °. A liquid crystal material having negative dielectric anisotropy was injected between the bonded liquid crystal substrate 22 and the counter substrate to manufacture a liquid crystal display device. When this was observed under crossed Nicols, it was found that good uniform alignment was obtained, and that substantially uniform rubbing treatment was performed over the entire surface of the substrate.

Comparative Example 11 A liquid crystal substrate 112 in which an alignment film was fired on a glass substrate was used in the same manner as in Example 11, except that the dummy substrate 27 was not used. The rubbing device shown in FIG. 18A having the same structure as the rubbing device shown in FIG. 18 was placed so that θ1 was 45 °.
The rubbing roller 113 was rotated in the forward direction, and the liquid crystal substrate 112 was subjected to a rubbing treatment by oblique rubbing. As for the counter substrate of the liquid crystal substrate 112, an alignment film is baked in the same manner as the liquid crystal substrate 112, and when it is bonded to the liquid crystal substrate 112, a rubbing process is performed by oblique rubbing so that the rubbing directions intersect at 90 °. A liquid crystal display device was produced by laminating the substrates in exactly the same manner as in Example 11.

When the produced liquid crystal display device was observed under crossed Nicols, streak-like unevenness was observed in the rubbing direction, and it was found that the rubbing treatment was performed nonuniformly.

Comparative Example 12 A liquid crystal substrate in which an alignment film was fired on a glass substrate was prepared in exactly the same manner as in Example 11, and a dummy substrate was not provided.
The rubbing device 110 shown in FIG.
One side 115 is inclined from the vertical direction 114 of the moving direction of the liquid crystal substrate 112 (arrow A direction) by an angle of 0 to ± 1 °,
That is, it was placed on the rubbing stage 111 so as to substantially coincide with the vertical direction 114. Rubbing roller 113
Was rotated in the forward direction to perform rubbing treatment on the liquid crystal substrate 112 by vertical rubbing. As for the counter substrate of the liquid crystal substrate 112, the alignment film is baked in the same manner as the liquid crystal substrate 112,
At the time of laminating with the liquid crystal substrate 112, rubbing treatment was performed by vertical rubbing so that the rubbing directions intersect each other at 90 °, and the liquid crystal display device was produced by laminating in exactly the same manner as in Example 11.

When the manufactured liquid crystal display device was observed under crossed Nicols, it was found that good uniform alignment was obtained, and that substantially uniform rubbing treatment was performed over the entire surface of the substrate. This suggests that the cause of the alignment failure in Comparative Example 11 is the arrangement of the liquid crystal substrate during rubbing, that is, the twisting of the tips of the rubbing cloth by the substrate edge. However, the arrangement of the liquid crystal substrate during rubbing, and thus the rubbing direction in the liquid crystal display portion that is the display area of the liquid crystal display device, may be defined by the arrangement of the retardation plate and the polarizing plate, and the viewing angle characteristics required accordingly. In many cases, the arrangement of the liquid crystal substrate of Comparative Example 12 is not always possible.

Embodiment 12 In exactly the same manner as in Embodiment 11, instead of disposing a dummy substrate for the liquid crystal substrate 22 having an alignment film baked on a glass substrate, the liquid crystal substrate 22 is moved onto the rubbing stage 31. 4 (a) used in Example 11 except that a protrusion having a side substantially perpendicular to the direction (arrow A direction) and a side in contact with the liquid crystal substrate 22 was formed. 6A was placed on the rubbing stage 31 of the rubbing apparatus shown in FIG. 6A so that θ1 was 45 °, and the rubbing treatment was performed by oblique rubbing in the same manner as in Example 11. The counter substrate of the liquid crystal substrate 22 is also rubbed by oblique rubbing so that when the alignment film is baked in the same manner as the liquid crystal substrate 22 and the liquid crystal substrate 22 is attached, the rubbing directions intersect each other at 90 °. A liquid crystal display device was produced by laminating the substrates in exactly the same manner as in Example 11.

When the produced liquid crystal display device was observed under crossed Nicols, it was found that good uniform alignment was obtained, and that substantially uniform rubbing treatment was performed over the entire surface of the substrate.

Example 13 As shown in FIG. 15, a liquid crystal display unit 5 was formed on a glass substrate.
The alignment film was formed in the same manner as in Example 11 except that 6 was inclined such that the four sides around it were inclined by θ5 (± 1 ° to ± 45 °) with respect to the four sides around the substrate surface of the liquid crystal substrate 52. Was fired to prepare a liquid crystal substrate 52. The liquid crystal substrate 52 on which the alignment film is fired is placed on the rubbing stage 51 of the rubbing device shown in FIG.
Angle 0 from the vertical direction 54 of the moving direction of 2 (arrow A direction)
It was placed so as to be tilted by ± 1 °, that is, so as to substantially coincide with the vertical direction 54. The rubbing process was performed on the liquid crystal substrate 52 by rotating the rubbing roller 53 in the forward direction. Therefore, the liquid crystal display unit 56 was obliquely rubbed.
The counter substrate of the liquid crystal substrate 52 is also the liquid crystal substrate 52.
In the same manner as in Example 11, the alignment film is baked, and when it is bonded to the liquid crystal substrate 52, a rubbing process is performed by oblique rubbing so that the rubbing directions intersect at 90 °, and the bonding is performed in exactly the same manner as in Example 11 to perform liquid crystal display. The device was made.

When the produced liquid crystal display device was observed under crossed Nicols, it was found that good uniform alignment was obtained, and that substantially uniform rubbing treatment was performed over the entire surface of the substrate.

As described above, according to the rubbing apparatuses of the first, second and third embodiments, a liquid crystal display that can obtain uniform alignment even in oblique rubbing with respect to homeotropic alignment (vertical alignment) cells in which alignment defects are likely to occur. The device can be made.

Further, it was found that rubbing defects are increased or decreased by adding a chiral component to a liquid crystal material when manufacturing a liquid crystal display device in the same manner as in the above-mentioned Examples and Comparative Examples. That is, when the ratio (d / p) of the width (d) between the substrates and the twist pitch (p) of the liquid crystal material is adjusted to be 0.2 to 0.35 by adding the chiral component, Other than, for example, d /
Compared to the case where p cannot be adjusted between 0.2 and 0.35,
The rubbing failure was significantly reduced.

The cause of this is not clear, but it can be considered as follows. For example, when the liquid crystal molecules are rubbed so that they are twisted by 90 ° on the upper and lower substrates,
90 ° due to subtle fluctuations in the tip of the hair during diagonal rubbing
A rubbing area having a twist angle other than the above occurs.
When a liquid crystal display device is manufactured using a substrate having such a region, the region is recognized as a rubbing failure.
However, even when a substrate having such a region is used, by adding an appropriate amount of a chiral component to the liquid crystal material, a spontaneous twist occurs in the liquid crystal layer, and the rubbing angle increases or decreases to some extent. Even so, it is considered that the force to hold the set twist angle (90 ° in this case) works, so that the rubbing failure may not be recognized.

Therefore, in the liquid crystal display device of the present invention, the addition of the chiral component causes the d / p to be 0.2 to 0.
The liquid crystal display device having a larger margin with respect to the rubbing condition can be obtained by adjusting the distance between 35 and 35.

[0112]

As described above, according to the present invention, the rotation direction of the roller at the position where the liquid crystal substrate and the rubbing material contact each other is set to be the same as the moving direction of the rubbing stage. Even in oblique rubbing in which the rubbing treatment is performed in a state where the side around the substrate surface of the liquid crystal substrate is tilted ± 1 ° to ± 45 ° with respect to the direction perpendicular to the moving direction of the liquid crystal substrate, the tip of the rubbing material is the surface of the liquid crystal substrate. Directly hit the
Since the edge of the substrate is not affected, the tips of the rubbing material do not twist obliquely with respect to the moving direction of the liquid crystal substrate,
It is possible to provide a rubbing device that is less likely to cause rubbing defects.

Further, according to the present invention, the side surface of the liquid crystal substrate, which is disposed on the front side in the moving direction of the liquid crystal substrate and is in contact with two sides forming the substrate surface of the liquid crystal substrate, and the vertical direction of the moving direction of the liquid crystal substrate. Since the dummy substrate having the side surface on the front end side including the side in the substantially coincident direction is provided, the hair tips of the rubbing material even in the oblique rubbing are of the dummy substrate set in the direction perpendicular to the moving direction of the liquid crystal substrate. Since the rubbing treatment can be performed by riding on the edge and moving onto the liquid crystal substrate without being twisted, it is possible to provide a rubbing device in which rubbing failure is unlikely to occur.

Further, according to the present invention, the display area, which is the display area of the liquid crystal display device, has four peripheral sides inclined by ± 1 ° to ± 45 ° with respect to the four peripheral sides of the liquid crystal substrate. In addition, since it is arranged on the liquid crystal substrate and one side of the liquid crystal substrate is arranged on the rubbing stage so that it is substantially aligned with the direction perpendicular to the moving direction of the liquid crystal substrate, the liquid crystal substrate itself is rubbed in the same manner as in the case of vertical rubbing. It is possible to provide a rubbing device capable of performing a rubbing process by oblique rubbing in the display unit without causing the hair tips on the surface of the roller to be twisted by the treatment.

Further, according to the present invention, since the liquid crystal substrate manufactured by the rubbing device is used, a liquid crystal display device that is uniformly aligned even in oblique rubbing with respect to a homeotropic alignment cell in which alignment defects are likely to occur is provided. You can

[Brief description of drawings]

FIG. 1 is a plan view showing a schematic configuration of a rubbing device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the section line II of FIG.

FIG. 3 is a sectional view schematically showing a state where the liquid crystal substrate 12 and the rubbing cloth 19 are in contact with each other.

FIG. 4 is a configuration diagram showing a schematic configuration of a rubbing device according to a second embodiment of the present invention. FIG. 4A is a plan view showing a schematic configuration of the rubbing apparatus of the second embodiment.
4B is a sectional view taken along the section line II-II of FIG.

FIG. 5 is a cross-sectional view schematically showing a rubbing process performed by the rubbing device shown in FIG.

FIG. 6A is a plan view showing the configuration of a second example of a rubbing stage used in the rubbing apparatus of the second embodiment. FIG. 6B is a sectional line III- of FIG.
It is sectional drawing seen from III.

7 is a liquid crystal substrate 22 on the rubbing stage 31 of FIG.
FIG. 6 is a plan view for explaining the size relationship between the dummy substrate 28 and the dummy substrate 28.

FIG. 8 is a cross-sectional view showing the configuration of an example in which the tip side of the dummy substrate is modified.

FIG. 9 is a cross-sectional view showing a configuration of a first example in which a liquid crystal substrate side of a dummy substrate is modified.

FIG. 10A is a sectional view showing a configuration of a second example in which the liquid crystal substrate side of the dummy substrate is modified. Figure 10
10B is a sectional view showing another configuration of the riding portion 35 of FIG. 10A.

FIG. 11A is a plan view showing a configuration of a third example in which the liquid crystal substrate side of the dummy substrate is modified. Figure 11
FIG. 11B is an enlarged view showing an enlarged part of the configuration of the contact portion between the dummy substrate and the liquid crystal substrate of FIG. 11A.

FIG. 12 is a sectional view taken along the section line IV-IV of FIG. 11 (b).

FIG. 13A is a plan view showing the configuration of a third example of a rubbing stage used in the rubbing apparatus of the second embodiment. FIG. 13B is a sectional view taken along the section line V-V in FIG.

FIG. 14 is a configuration diagram showing a schematic configuration of a rubbing device according to a third embodiment of the present invention.

15 is a plan view showing an example of the arrangement of liquid crystal display portions on the liquid crystal substrate 52 placed on the rubbing apparatus of FIG.

16 is a plan view showing another example of the arrangement of the liquid crystal display section on the liquid crystal substrate 62 mounted on the rubbing apparatus of FIG.

17 (a) is a plan view showing a schematic configuration of a conventional rubbing apparatus, and FIG. 17 (b) is a plan view of FIG.
It is sectional drawing seen from the cutting plane line VI-VI of (a).

FIG. 18A is a plan view showing one configuration of the substrate arrangement with respect to the rollers during rubbing. Figure 1
FIG. 8B is a plan view showing another configuration of the substrate arrangement with respect to the roller during rubbing.

19 (a) is a plan view schematically showing a twisting direction of a tip of a roller, which occurs in the substrate arrangement shown in FIG. 18 (a). FIG. 19B is a plan view schematically showing the twisting direction of the tips of the rollers generated in the substrate arrangement of FIG. 18B.

FIG. 20 is a cross-sectional view for explaining a rubbing state due to forward rotation of the roller.

FIG. 21 is a rubbing material and a liquid crystal substrate 1 shown in FIG.
It is a figure which expands and shows the vicinity of the position 120 which 12 contacts.

FIG. 22 is an isocontrast curve diagram showing an example of viewing angle characteristics in a vertically aligned cell.

[Explanation of symbols]

10 Rubbing device 11 rubbing stage 12 LCD substrate 13 Rubbing roller 14 Vertical direction of moving direction of liquid crystal substrate 15 One side of liquid crystal substrate

Claims (18)

[Claims] 1. A rubbing stage having at least a liquid crystal substrate on which an alignment film is formed and movable, and a roller holding a rubbing material for rubbing the liquid crystal substrate on the outer periphery of a cylindrical rotating body. A rubbing device, wherein the liquid crystal substrate is arranged such that a side around the substrate surface is inclined ± 1 ° to ± 45 ° with respect to a direction perpendicular to a moving direction of the liquid crystal substrate, and the liquid crystal substrate and the rubbing material are provided. The rubbing device is characterized in that the rotation direction of the roller and the moving direction of the rubbing stage are in the same direction at a position where they contact each other. 2. A rubbing stage having a liquid crystal substrate on which an alignment film is formed and movable, and a roller holding a rubbing material for rubbing the liquid crystal substrate on the outer periphery of a cylindrical rotating body. In the rubbing device, the liquid crystal substrate is arranged such that a side around the substrate surface is inclined ± 1 ° to ± 45 ° with respect to a vertical direction of a moving direction of the liquid crystal substrate, and A dummy substrate having a liquid crystal substrate side surface in contact with two sides arranged on the front side and a tip side surface including a side inclined by 0 to ± 1 ° with respect to a direction perpendicular to the moving direction is arranged. A rubbing device. 3. The rubbing device according to claim 2, wherein the thickness of the dummy substrate is equal to or larger than the thickness of the liquid crystal substrate. 4. The surface of the dummy substrate on the side of the tip end contacts a surface of the dummy substrate which contacts the rubbing stage.
The rubbing device according to claim 2, wherein the rubbing device is a slope having an angle of less than °. 5. The liquid crystal substrate side surface of the dummy substrate is an inverse slope forming an angle of more than 90 ° and less than 180 ° with a surface of the dummy substrate in contact with the rubbing stage. The rubbing device according to any one of to 4. 6. The maximum width of the dummy substrate in the direction perpendicular to the moving direction of the liquid crystal substrate is greater than or equal to the maximum width of the liquid crystal substrate in the direction perpendicular to the moving direction of the liquid crystal substrate. The rubbing device according to any one of the above. 7. The liquid crystal substrate side surface of at least a part of the dummy substrate has a riding portion on which the dummy substrate extends over the liquid crystal substrate, according to any one of claims 2 to 6. Rubbing device. 8. The side surface of the riding portion is 0 with respect to a moving direction of the liquid crystal substrate and a direction perpendicular to the moving direction.
The rubbing device according to claim 7, wherein the rubbing device is configured only by a side surface including a side inclined by ± 1 °. 9. A surface, of the side surface of the riding portion, including a side inclined by 0 to ± 1 ° with respect to a direction perpendicular to the moving direction of the liquid crystal substrate, the surface being in contact with the liquid crystal substrate of the riding portion. The rubbing device according to claim 8, wherein the rubbing device is an inverse slope having an angle of more than 90 ° and less than 180 °. 10. The side surface of the dummy substrate on the liquid crystal substrate side is composed of only side surfaces each including a side inclined by 0 to ± 1 ° with respect to a moving direction of the liquid crystal substrate and a direction perpendicular to the moving direction. The rubbing apparatus according to claim 1, wherein the rubbing apparatus is a rubbing apparatus. 11. The rubbing apparatus according to claim 2, wherein a film made of metal or polymer is fixed on the dummy substrate, and the film is arranged so as to cover a part of the liquid crystal substrate. 12. The thickness of the film is 10 to 200 μm.
12. The rubbing apparatus according to claim 11, wherein the rubbing device is m, and the sum of the thickness of the film and the thickness of the dummy substrate is not less than the thickness of the liquid crystal substrate. 13. The rubbing apparatus according to claim 2, wherein the dummy substrate is provided as a protrusion on a rubbing stage. 14. A rubbing stage having at least a liquid crystal substrate on which an alignment film is formed and movable, and a roller holding a rubbing material for rubbing the liquid crystal substrate on the outer periphery of a cylindrical rotating body. A rubbing device, wherein a display unit serving as a display region of the liquid crystal display device is provided on the liquid crystal substrate, and the four sides around the display unit are ± 1 ° to ± respectively with respect to the four sides around the substrate surface of the liquid crystal substrate. A rubbing device, which is disposed at an angle of 45 ° and is arranged on a rubbing stage with one side thereof being inclined at an angle of 0 to ± 1 ° with respect to a direction perpendicular to the moving direction of the liquid crystal substrate. 15. The alignment film formed on the liquid crystal substrate,
The rubbing device according to claim 1, wherein the rubbing device is a homeotropic alignment film. 16. A liquid crystal display device comprising a pair of substrates on which at least an electrode and an alignment film are formed, wherein at least one of the pair of substrates is a substrate. A liquid crystal display device manufactured by using a rubbing device. 17. The rubbing direction of one substrate is twisted by approximately 90 ° with respect to the rubbing direction of the other substrate between the pair of substrates.
6. The liquid crystal display device according to item 6. 18. The liquid crystal material filled between the pair of substrates contains a chiral component, and a ratio (d / p) of a width (d) between the pair of substrates and a twist pitch (p) of the liquid crystal material is 18. The liquid crystal display device according to claim 16, wherein the liquid crystal display device is adjusted to a value between 0.2 and 0.35.