CN111522177B

CN111522177B - Rubbing treatment method, method for manufacturing liquid crystal panel, and method for manufacturing optical film

Info

Publication number: CN111522177B
Application number: CN202010077530.1A
Authority: CN
Inventors: 谷池康司郎; 有木幸市; 冈本章男
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2019-02-04
Filing date: 2020-01-30
Publication date: 2022-11-15
Anticipated expiration: 2040-01-30
Also published as: CN111522177A

Abstract

Provided are a rubbing treatment method, a method for manufacturing a liquid crystal panel, and a method for manufacturing an optical film, which can realize a uniform rubbing state and have stability. A rubbing treatment method for rubbing a cylindrical roller core (12A, 13A) with a rubbing cloth (12B, 13B) while rotating a rubbing roller (12, 13) having a rotating shaft (12C, 13C) parallel to a surface to be rubbed of an object (20) to be rubbed and having the rubbing cloth (12B, 13B) on the outer periphery of the roller core, wherein the number of rotations of the rubbing roller (12, 13) is set based on the material of the roller core (12A, 13A).

Description

Rubbing treatment method, method for manufacturing liquid crystal panel, and method for manufacturing optical film

Technical Field

The invention relates to a rubbing treatment method, a method for manufacturing a liquid crystal panel, and a method for manufacturing an optical film.

Background

For example, in a liquid crystal panel or an optical film in which optical characteristics are obtained by orienting liquid crystal molecules, a rubbing method of wiping a surface of an alignment film or a base material formed on a substrate with cloth or the like has been widely used. Specifically, a technique of rubbing a rubbing roll having a rubbing cloth attached to its surface by relatively moving the rubbing roll and a substrate or film with an alignment film while rotating the rubbing roll has been widely used.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 5-142542

Disclosure of Invention

Problems to be solved by the invention

However, in the treatment by the rubbing method, a local band unevenness, a rubbing defect such as a streak or a flaw frequently occurs in the object after rubbing. Such rubbing defects cause alignment defects of liquid crystal molecules, and cause, for example, unevenness in alignment regulating force for maintaining the initial alignment state of liquid crystal sandwiched between a pair of substrates in a completed liquid crystal panel. That is, the liquid crystal panel has a problem that luminance unevenness occurs and display quality is degraded. Such a rubbing defect is considered to be caused by the hardness of the object to be treated, the type and surface condition of the rubbing cloth used, or the stability of the rubbing device.

Among these reasons, in order to obtain good optical characteristics in a liquid crystal panel or an optical film, the hardness of an alignment film or a film as a treatment object, and the type and surface state of a rubbing cloth used are sometimes limited. In order to suppress the frictional failure in this case, it is particularly important to ensure the stability of the apparatus.

The present invention has been made in view of the above-described situation, and an object thereof is to provide a rubbing treatment method, a method for manufacturing a liquid crystal panel, and a method for manufacturing an optical film, which can achieve a uniform rubbing state and have stability.

Means for solving the problems

In the conventional friction device, a rotation speed of a friction roller is set by evaluating a state or a characteristic of a processed object after friction. In order to eliminate as much as possible at least the cause of a friction failure in a friction device itself (not including a friction cloth), the present invention focuses on the friction device itself rather than on a workpiece, and attempts to improve the characteristics of the workpiece by improving the stability thereof.

Further, the inventors of the present invention have made extensive studies on the stability of the friction device, and as a result, have found that ranges of the number of rotations with a small amount of eccentricity are independently present depending on the material of the roll core (core around which the rubbing cloth is wound) of the rubbing roll. That is, it was found that by determining the rotation speed of the rubbing roller based on the range of rotation speeds in which the amount of misalignment is small, unevenness of the object to be treated can be suppressed, and a more uniform rubbing state can be obtained. That is, embodiments of the present invention for solving the above problems are as follows.

(1) An embodiment of the present invention is a rubbing treatment method for rubbing a cylindrical roller core with a rubbing cloth on its outer periphery while rotating a rubbing roller having a rotating shaft parallel to a surface to be rubbed of an object to be rubbed, wherein the rotating speed of the rubbing roller is set based on a material of the roller core.

(2) In addition, according to an embodiment of the present invention, in the configuration of the above (1), the roll core is made of carbon, and the rotation speed is set to 1000 to 2300rpm.

(3) In addition, according to an embodiment of the present invention, in the configuration of the above (1), the roll core is made of aluminum metal, and the rotation speed is set to 650 to 1100rpm.

(4) In addition, according to an embodiment of the present invention, in addition to any one of the configurations (1) to (3), the rubbing rollers include at least a 1 st rubbing roller and a 2 nd rubbing roller which rub the object in the conveying direction in order, and the respective core rollers of the 1 st rubbing roller and the 2 nd rubbing roller are made of the same material, while the object is conveyed in a predetermined direction and the rubbing cloth is wiped on the conveying path.

(5) Another embodiment of the present invention is a method for manufacturing a liquid crystal panel, including at least: an alignment film forming step of forming an alignment film on a substrate; and a rubbing treatment step of rubbing the alignment film by the rubbing treatment method according to any one of the above (1) to (4).

(6) Another embodiment of the present invention is a method for producing an optical film, including at least a rubbing step of rubbing a surface of the film by the rubbing method of any one of the above (1) to (4).

Effects of the invention

According to the present invention, it is possible to provide a rubbing treatment method, a method for manufacturing a liquid crystal panel, and a method for manufacturing an optical film, which can realize a uniform rubbing state and have stability.

Drawings

FIG. 1 is a schematic view of a friction device according to one embodiment.

Fig. 2 is a schematic view showing a measurement site of the roll core.

Fig. 3 is a table showing the results of (experiment 1).

Fig. 4 is a graph showing the result of (experiment 1).

Fig. 5 is a table showing the results of (experiment 2).

Fig. 6 is a graph showing the result of (experiment 2).

Fig. 7 is a table showing the results of (experiment 3).

Fig. 8 is a graph showing the result of (experiment 3).

Fig. 9 is a graph showing the result of (experiment 3).

Fig. 10 is a table showing the results of (experiment 4).

Fig. 11 is a graph showing the result of (experiment 4).

Fig. 12 is a graph showing the result of (experiment 4).

Fig. 13 is a table showing the results of the 1 st roll core (experiment 5).

Fig. 14 is a graph showing the results of the 1 st roll core (experiment 5).

Fig. 15 is a graph showing the results of the 1 st roll core (experiment 5).

Fig. 16 is a table showing the results of the 2 nd roll core (experiment 5).

Fig. 17 is a graph showing the results of the 2 nd roll core (experiment 5).

Fig. 18 is a graph showing the results of the 2 nd roll core (experiment 5).

Fig. 19 is a table showing the results of (experiment 6).

Description of the reference numerals

10: friction device, 11: stage, 12: first friction roller, 12A: 1 st roll core, 12B: 1 st friction material (friction cloth), 12C: 1 st rotation axis, 13: second friction roller, 13A: 2 nd roll core, 13B: no. 2 friction material (friction cloth), 13C: 2 nd rotation axis, 15: drive motor, 16: support shaft, 20: substrate (rubbed object), 20A: surface (rubbed surface).

Detailed Description

Fig. 1 illustrates a friction device 10 according to an embodiment. The rubbing device 10 of the present embodiment is, for example, a device for rubbing the surface of a substrate 20 for a liquid crystal panel coated with an alignment film, and includes a pair of rotatable rubbing rollers 12 and 13 above a transport path of a stage 11 for suction-holding the substrate 20. One of the pair of friction rollers 12 and 13 is a 1 st friction roller 12 disposed on the upstream side in the conveyance direction, and the other friction roller is a 2 nd friction roller 13 disposed on the downstream side in the conveyance direction from the 1 st friction roller 12. The rubbing process is performed by wiping the surface 20A of the substrate 20 with the rubbing rollers 12 and 13 on the conveyance path while conveying the substrate 20 in a predetermined direction (from right to left in fig. 1).

The 1 st friction roller 12 and the 2 nd friction roller 13 are each formed by winding a 1 st friction member 12B and a 2 nd friction member 13B in a cloth form around a 1 st roller core 12A and a 2 nd roller core 13A each having a cylindrical shape, and the

rotation axes

12C and 13C are arranged in a direction parallel to the surface 20A of the substrate 20 and intersecting the conveyance direction. One end Side (left Side in fig. 2) of the rotating

shafts

12C, 13C of the respective friction rollers 12, 13 is a Driving end (Driving Side) 12CL, 13CL connected to a Driving motor 15 as a Driving source via a support shaft 16, and the other end Side is a Free end (Free Side) 12CR, 13CR connected to the support shaft 16. That is, the friction rollers 12 and 13 are of a single-side drive type.

The lengths and diameters of the

respective roll cores

12A and 13A of the 1 st friction roll 12 and the 2 nd friction roll 13 are set to be the same. The 1 st friction roller 12 and the 2 nd friction roller 13 can be set independently of each other in rotation direction, rotation speed, height with respect to the substrate 20 (stage 11), and the like. The number of revolutions is defined by the number of revolutions per unit time of the rubbing rolls 12 and 13 (rpm/revolution per 1 minute). The heights of the friction rollers 12 and 13 from the stage 11 are set so that not only the pressing amounts (fiber contact amounts) of the friction members 12B and 13B with the substrate 20 can be adjusted, but also the friction members 12B and 13B are not in contact with the substrate 20 by setting only one of the friction rollers 12 or 13 in contact with the substrate 20 and the other friction roller in a state of being separated from the substrate 20. Further, whether or not the friction rollers 12 and 13 rotate can be independently controlled.

One of the reasons why the substrate 20 is unevenly distributed in the rubbing process by the rubbing device 10 is the eccentricity of the rubbing rollers 12 and 13 during the rubbing process, that is, during the high-speed rotation. When the misalignment amount becomes large, a portion where the load locally becomes large is generated on the substrate 20, and thus it is difficult to perform uniform alignment treatment on the alignment film. That is, in order to uniformly rub the alignment film formed on the substrate 20 with a constant strength, it is important to keep the distance between the rubbing rollers 12 and 13 and the substrate 20 (stage 11) constant.

Based on this finding, the following experiment was performed to investigate the cause of the misalignment of the rubbing roller. Specifically, the friction rollers 12 and 13 of the friction device 10 were set to be only the

roller cores

12A and 13A without the friction members 12B and 13B wound therearound, and the amount of eccentricity of the

roller cores

12A and 13A was measured when the material, length, and rotational speed of the

roller cores

12A and 13A were changed. In addition, in order to prevent the

roll cores

12A and 13A from being affected by the substrate 20 or the stage 11, measurement was performed at a height sufficiently apart from them.

< verification in case where a single roll is used >

1. Case of using aluminum metal roll core in single piece

(experiment 1)

As the 1 st core 12A of the 1 st friction roller 12, the relationship between the number of revolutions and the amount of misalignment was examined when the core 12A of aluminum metal having a diameter of 150mm × a length of 1850mm was rotated clockwise when viewed from the driving end 12 CL. The amount of core displacement was measured by using a laser displacement meter (KeyenceLT-8110). As shown in fig. 2, the measurement site was a total of three sites, i.e., two sites (L, R) located 10mm inward from both ends in the axial direction of the roll core 12A and one site (C) at the center, and each measurement was performed twice. During the measurement, the 2 nd roll core 13A is kept stopped. In addition, the amount of core displacement in the case of using a rubbing roll having a length of less than 2500mm is preferably 5.0 μm or less. The measurement results are shown in table 1 of fig. 3 and the graphs of fig. 4.

As shown in the table of fig. 3 and the graph of fig. 4, when the roll core 12A is made of aluminum metal, the amount of misalignment is 5.0 μm or less at any position in the axial direction when the rotation speed is set to 650 to 1100rpm, and the 1 st roll core 12A can be driven in a stable state with a small amount of misalignment.

2. Case where the carbon roll core is used singly-1

(experiment 2)

As the 1 st core 12A of the 1 st friction roll 12, the relationship between the number of revolutions and the amount of misalignment when the carbon core 12A was rotated clockwise when viewed from the drive end 12CL side was examined. As in experiment 1, the roll core 12A used a roll core having a diameter of 150 mm. Times.a length of 1850mm, and the total of three measurement sites were measured twice. The amount of core displacement was measured by using a laser displacement meter (KeyenceLT-8110). During the measurement, the 2 nd core 13A is kept stopped. The measurement results are shown in table 2 of fig. 5 and the graph of fig. 6.

As shown in the table of fig. 5 and the graph of fig. 6, when the carbon roll core is used as the roll core 12A, the amount of eccentricity is 5.0 μm or less at any position in the axial direction when the rotation speed is set to a range of 1000 to 2300rpm, and the 1 st roll core 12A can be driven in a stable state with a small amount of eccentricity.

As described above, it was found from (experiment 1) and (experiment 2) that the ranges of the rotational speeds in the stable state in which the amount of misalignment is small are different between the case where the material of the roll core 12A is made of aluminum and the case where the material is made of carbon even when the roll core 12A of the same form is used.

3. Case of using carbon roll cores individually-2

(experiment 3)

As the 1 st core 12A of the 1 st friction roller 12, the relationship between the number of revolutions and the amount of eccentricity (Fcw) when a carbon core 12A having a diameter of 140mm × a length of 3880mm, which is longer than the core of the above (experiment 2), was rotated clockwise when viewed from the drive end 12CL side was examined. The measurement sites were three sites in total, two sites (L, R) 680mm inward from both ends of the roll core 12A and the center (C).

Further, the relationship between the rotation speed and the misalignment amount (Fccw) when the 1 st roll core 12A is rotated counterclockwise when viewed from the drive end 12CL side was examined. The measurement site is a central site in the axial direction of the 1 st roll core 12A.

Both of them were measured for the amount of core displacement by using a laser displacement meter (Keyenecl-H050). During the measurement, the 2 nd roll core 13A is kept stopped. In addition, the amount of core displacement when a rubbing roll having a length of 2500mm or more and 4000mm or less is used is preferably 35.0 μm or less. The measurement results are shown in table 3 of fig. 7 and the graphs of fig. 8 and 9.

As shown in the table of fig. 7 and the graphs of fig. 8 and 9, the misalignment amount becomes 25.0 μm or less at any position in the axial direction in the range of the rotation speed of 1000 to 2400rpm, and becomes smaller than that in the case of the rotation speed outside the range. As is clear from the graph of fig. 9 in which the center portions are compared with each other, there is no great difference between the case (Fcw) in which the roll core 12A is rotated clockwise when viewed from the driving end 12CL and the case (Fccw) in which the roll core 12A is rotated counterclockwise when viewed from the driving end 12CL, and it can be confirmed that the same tendency is exhibited.

The findings (experiment 2) and (experiment 3) above were that, if the material of the roll core is the same, the friction device can be brought into a stable state with a small amount of misalignment at a rotation speed within a certain specific range regardless of the length or the rotation direction of the roll core. For example, when the roller core is made of carbon, the friction device can be set to a more stable state in a rotation speed range of 1000 to 2300rpm regardless of the length or the rotation direction thereof, compared to a case where the rotation speed is in another range under the same conditions.

In recent years, the length of the rubbing roll tends to be longer as the size of the mother glass is increased. Further, the rotation direction of the rubbing roll tends to be restricted in a situation where the uneven shape of the underlying structure (such as a pattern on the surface of the substrate) becomes complicated. Under such circumstances, the above experiment newly found the condition of the friction device side that can perform stable friction independent of the length or the rotational direction.

However, when the length of the roll core becomes long, the roll core itself is deflected, and therefore the magnitude of the misalignment itself tends to become larger than when the roll core is short. For example, in the range of the number of revolutions of 1000 to 2300rpm, the amount of eccentricity was 5.0 or less in the case where the roll core was less than 2500mm (experiment 2), but was 25.0 μm or less in the case where the roll core was 2500mm or more (experiment 3).

However, in practice, the rubbing treatment is performed when the length of the rubbing roll is 4000mm or less. This is because, when a large substrate, which requires a rubbing roller having a length of 4000mm or more, is subjected to a rubbing treatment, the rubbing roller is greatly deflected, and the amount of misalignment is significantly increased. Therefore, when such a large-sized substrate is subjected to alignment treatment, a non-contact photo-alignment technique is used instead of a contact rubbing treatment.

Under such circumstances, it is sufficient to assume that the rubbing roll has a length of 4000mm or less, and the amount of core displacement when a rubbing roll having a length of 2500 to 4000mm is used is preferably 35.0 μm or less. In (experiment 3), the core shift amounts in the case where the number of revolutions was set in the range of 1000 to 2400rpm were all 25.0 μm or less, and it can be said that the core shift amounts were sufficiently within the range.

(experiment 4)

In the above (experiment 3), the 1 st roll core 12A was examined, and the 2 nd roll core 13A was subjected to the same experiment. That is, as the 2 nd core 13A of the 2 nd friction roller 13, the relationship between the rotation speed and the misalignment amount (Rcw) when the carbon core 13A having a diameter of 140mm × a length of 3880mm was rotated clockwise as viewed from the drive end 13CL side was examined in the same manner as in (experiment 3). The measurement sites were two sites (L, R) 680mm from both ends to the inside of the roll core 13A, and three sites in total at the center (C).

Further, the relationship between the rotation speed and the misalignment amount (Rccw) when the 2 nd roll core 13A was rotated counterclockwise when viewed from the drive end 13CL side was examined. The measurement site is set to the central site in the axial direction of the 2 nd roll core 13A.

Both of them were measured for the amount of core displacement by using a laser displacement meter (Keyenecl-H050). During the measurement, the 1 st roll core 12A is kept stopped. The measurement results are shown in table 4 of fig. 10 and the graphs of fig. 11 and 12.

As shown in table 4 of fig. 10 and the graphs of fig. 11 and 12, in the range of the rotation speed of 1000 to 2400rpm, the misalignment amount becomes 31.0 μm or less at any position in the axial direction, and becomes smaller as compared with the case of the rotation speed outside the range, substantially as in the above (experiment 3). As is clear from the graph of fig. 12 in which the center portions are compared with each other, it can be confirmed that a large difference is not generated in a range of a preferable rotation speed in both the case (Rcw) in which the core 13A is rotated clockwise when viewed from the driving end 13CL side and the case (Rccw) in which the core is rotated counterclockwise, and that substantially the same tendency is exhibited. In the vicinity of 2500rpm, which is a preferable range of the rotation speed, the instability in the case of counterclockwise rotation (Rccw) is more remarkable.

Further, it is considered that some difference in the measured values between the 1 st roll core 12A and the 2 nd roll core 13A is caused by the individual difference of the roll cores. When the roll core is a large-sized roll core, the center of gravity may be deviated, and the end portion of the roll core may be specially processed to finely adjust the balance. Therefore, it is considered that the finished product of the roll core causes individual differences, and a difference in the amount of core displacement is caused due to the individual differences.

< verification in case of using two rolls >

In the case where both the 1 st rubbing roller 12 and the 2 nd rubbing roller 13 are used, there is a concern that the influence of resonance may occur. Therefore, the relationship between the rotation speed and the misalignment amount of the

respective roll cores

12A and 13A when the two friction rolls 12 and 13 are used was examined.

4. The case where two roll cores of the same type (made of carbon) were used and the rotation direction was changed (experiment 5)

As the 1 st roll core 12A and the 2 nd roll core 13A,

carbon roll cores

12A and 13A having a diameter of 140mm × a length of 3880mm were used, and the relationship between the number of revolutions and the amount of eccentricity of the 1 st roll core 12A and the 2 nd roll core 13A was examined when the directions of rotation of the

roll cores

12A and 13A were changed as in the following (1) to (3).

(1) The case where both the 1 st core 12A and the 2 nd core 13A are rotated clockwise when viewed from the driving ends 12CL and 13CL sides (Fcw-Rcw)

(2) A case where the 1 st core 12A is rotated counterclockwise when viewed from the driving end 12CL side and the 2 nd core 13A is rotated clockwise when viewed from the driving end 13CL side (Fccw-Rcw)

(3) A case where the 1 st core 12A is rotated clockwise when viewed from the driving end 12CL side and the 2 nd core 13A is rotated counterclockwise when viewed from the driving end 13CL side (Fcw-Rccw)

The measurement site is set to a total of three sites of two sites (L, R) at 680mm inward from both ends of the roll core 12A and the center (C) in the case of (1), and is performed at one site (C) at the center in the axial direction of each of the

roll cores

12A and 13A in the cases of (2) and (3). The amount of core displacement was measured by using a laser displacement meter (Keyence LK-H050).

The measurement results of the 1 st roll core 12A are shown in table 5 and fig. 14 and 15 of fig. 13. The measurement results of the 2 nd core 13A are shown in table 6 of fig. 16 and the graphs of fig. 17 and 18.

As is clear from these tables and the graphs, when two roll cores are used, in the case where carbon roll cores are used as the

roll cores

12A and 13A, the amount of eccentricity is 35.0 μm or less in at least the range of the rotation speed of 1000 to 2300rpm regardless of the combination of the rotation directions, and is smaller than that in the other ranges, as in the case of the above (experiment 2) or (experiment 3). That is, it is found that the difference caused by the difference in the rotational direction is small and can be substantially ignored.

In addition, in the 1 st roll core 12A, when the test (test 3) used with a single core and the present test (test 5) used with two cores were compared, almost no difference was observed in the tendency of the change in the rotation speed and the misalignment amount in the range of the rotation speed of 1000 to 2300rpm. The magnitude of the eccentricity is slightly larger as a whole in the present experiment (experiment 5), and the difference is a degree that can be roughly ignored. That is, even when two roll cores are driven simultaneously, the roll cores made of the same material are hardly affected by resonance.

On the other hand, when (experiment 4) and the present experiment (experiment 5) were compared with each other in the same manner with respect to the 2 nd roll core 13A, the tendency of the change in the rotation speed and the amount of misalignment did not match as in the 1 st roll core 12A in the range of the rotation speed of 1000 to 2300rpm, and it could not be said which of the amounts of misalignment was larger as a whole. However, within this range, the core displacement is 31.0 μm or less, and it can be said that the core displacement falls sufficiently within the preferable core displacement of 35.0 μm as in the 1 st roll core 12A. It is considered that some difference in the measurement results of the 1 st core 12A and the 2 nd core 13A is caused only by the influence of individual difference of each core.

5. The case of using different material roller cores in combination

(experiment 6)

In the above (experiment 5), it was confirmed that the influence of resonance due to the difference in the rotational direction of the

roll cores

12A and 13A is almost not considered when the two

roll cores

12A and 13A made of the same material are used, and therefore, in order to examine the influence of resonance due to the difference in the material of the

roll cores

12A and 13A, the relationship between the rotational speed and the misalignment amount was examined for the following cases (1) to (3).

(1) The 1 st roll core 12A and the 2 nd roll core 13A are both made of aluminum

(2) The 1 st roll core 12A is made of aluminum metal and the 2 nd roll core 13A is made of carbon

(3) The 1 st roll core 12A and the 2 nd roll core 13A are made of carbon

As the 1 st core 12A and the 2 nd core 13A, cores having a diameter of 150mm × a length of 1800mm were used, and the amount of eccentricity (Rccw) of the 2 nd core 13A was measured when they were rotated counterclockwise as viewed from the driving ends 12CL and 13 CL. The measurement site is the center of the axial direction, and the number of revolutions is measured in the range of 450 to 1200 rpm. The amount of core displacement was measured by using a laser displacement meter (HL-C2 manufactured by Panasonic). Then, the ratio of the magnitude of the misalignment amount (Rccw) of the 2 nd core 13A when different cores are used as in (2) above was calculated, assuming that the misalignment amount of the 2 nd core 13A when cores of the same material are used as in (1) or (3) above is 1. The results are shown in the table of fig. 19.

As can be seen from the table of fig. 9, the misalignment amount of the above (2) using the cores of different materials at any rotation speed was significantly higher than the misalignment amounts of the above (1) and (3) using the cores of the same material by a factor of 1.30 to 7.07, and was not lower than the misalignment amount in the case of using the cores of the same material. The reason for this is presumed to be that the roller cores made of different materials, in other words, the roller cores made of different weights are affected by resonance. That is, when a plurality of rubbing rolls are used, it can be confirmed that roll cores of the same material having the same weight are preferably used.

The matters found from the results of the above (experiment 1) to (experiment 6) are as follows.

When an aluminum metal roll core is used as the roll core of the friction roll, the rotation speed is preferably set in the range of 650 to 1100rpm.

When a carbon roll core is used as the core of the friction roll, the rotation speed is preferably set in the range of 1000 to 2300rpm.

When a plurality of friction rollers are used, it is preferable to use roller cores of the same material having the same weight.

These matters do not relate to the length of the

roll cores

12A, 13A or the rotation direction of the

roll cores

12A, 13A.

Therefore, by performing the rubbing treatment based on these conditions, even when other conditions are changed, the rubbing treatment can be performed in a preferable state in terms of stability of the rubbing device 10, and thus a uniform rubbing state can be achieved.

Based on the above findings, an alignment film was formed on a substrate for a liquid crystal panel (alignment film formation step), and then a rubbing treatment was performed on the alignment film under the above-described conditions (rubbing treatment step), thereby producing a liquid crystal panel. As a result, the following liquid crystal panel can be obtained: a uniform rubbing state is obtained, unevenness in luminance is suppressed, and display quality is excellent.

< other embodiments >

The present invention is not limited to the embodiments illustrated by the above description and the drawings, and for example, the following embodiments are also included in the technical scope of the present invention.

(1) In the above embodiment, the rubbing device 10 (rubbing treatment method) for rubbing the alignment film coated on the surface 20A of the substrate 20 for a liquid crystal panel is described, but the rubbing device 10 is not limited to the above embodiment, and can be applied to a rubbing device (rubbing treatment method) for various objects to be rubbed such as a rubbing device for rubbing a base material (film) of an optical film (rubbing treatment step).

(2) In the above embodiment, the embodiment has been described in which one or two rubbing rollers are used, but the number of rubbing rollers may be three or more.

(3) In addition, the length or diameter of the roll core is not limited to the above embodiments. Further, the rotation direction of the roll core can be appropriately changed.

Claims

1. A rubbing treatment method for rubbing a cylindrical roller core with a rubbing cloth on the outer circumference thereof while rotating a rubbing roller having a rotating shaft parallel to a surface to be rubbed of an object to be rubbed,

the rotation speed of the friction roller is set based on the material of the roller core.

2. The friction treatment method according to claim 1,

the roll core is made of carbon, and the rotation speed is set to 1000 to 2300rpm.

3. The friction treatment method according to claim 1,

the roll core is made of aluminum metal, and the rotation speed is set to 650 to 1100rpm.

4. The rubbing treatment method according to any one of claim 1 to claim 3,

while the object to be rubbed is being conveyed in a predetermined direction, the rubbing cloth is wiped on the object to be rubbed on the conveying path,

the friction rollers include at least a 1 st friction roller and a 2 nd friction roller which rub against each other in order in the conveying direction of the object to be rubbed, and the roller cores of the 1 st friction roller and the 2 nd friction roller are made of the same material.

5. A method for manufacturing a liquid crystal panel, comprising:

an alignment film forming step of forming an alignment film on a substrate; and

a rubbing treatment step of rubbing the alignment film by the rubbing treatment method according to claim 1.

6. A method for manufacturing an optical film, characterized in that,

at least comprising a rubbing treatment step of rubbing-treating the surface of the film by the rubbing treatment method according to claim 1.