JPH08334768A - Orientation treatment of oriented film - Google Patents

Abstract

PURPOSE: To obtain high orientability even for an oriented film which is hardly subjected to a rubbing treatment by irradiating this oriented film with ion beams. CONSTITUTION: A substrate 2 with the oriented film is formed by applying the oriented film 6 consisting of a high-polymer org. material, such as polyimide, on the surface of, for example, a glass substrate 4. The surface of the oriented film 6 is irradiated with the ion beams 14 by sharpening an irradiation angle θfrom diagonal above at the time of the orientation treatment. The orientation order angle of liquid crystals increases as the irradiation angle 6 is set smaller and, therefore, the setting of this angle at the smaller value is more preferable. The direction of the irradiation on the oriented film 6 with the ion beams and the rubbing direction to the oriented film 6 are set at nearly the same directions even if whichever treatment is execute first. Both treatment directions to the same oriented films 6 are eventually unified and the respective orientation treatments make up each other if both are set in nearly the same directions and, therefore, the same rubbing directions are more preferable for obtaining the higher orientability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, in the manufacture of liquid crystal displays and the like, in which an alignment treatment for aligning liquid crystal molecules in a predetermined direction is performed. Regarding processing method.

[0002]

2. Description of the Related Art In order to align liquid crystal molecules in a certain direction on the surface of a substrate, an alignment film made of a high molecular organic material such as polyimide is applied to the surface of the substrate.

In this case, if the alignment film is simply applied to the surface of the substrate, the liquid crystal molecules are aligned in parallel with the surface of the substrate, and the liquid crystal molecules are aligned (aligned) in a certain direction.
I can't let you do it.

Therefore, conventionally, the alignment film is subjected to alignment treatment by mechanically rubbing (rubbing) the surface of the alignment film in a certain direction with a rubbing cloth such as nylon or rayon. It has been performed to orient in a direction having a fixed relationship.

[0005]

However, in the conventional alignment treatment method as described above, it is difficult to perform rubbing treatment and high alignment property is obtained depending on the kind of the polymer organic material forming the alignment film. There is a problem that you cannot do it.

A typical organic alignment film that is hard to be rubbed is a polymer organic material having a long molecular structure. More specifically, the number of monomer units (that is, the degree of polymerization) n
Is 1000 or more polyamide, polyimide, soluble polyimide, polycarbonate, polyester, polysulfone, polyether sulfone, polyether ketone, polyamide imide, or polyether imide in which the number n of monomer units is 100 or more.

It is considered that such a high molecular weight organic material is difficult to be rubbed because it has a long molecular structure and it is difficult to arrange the molecular structures in a certain direction even after rubbing.

Therefore, the main object of the present invention is to provide an alignment treatment method capable of obtaining a high alignment property even in an alignment film which is difficult to be subjected to a rubbing treatment.

[0009]

In order to achieve the above object, the first alignment treatment method of the present invention is for aligning liquid crystal molecules formed on a substrate and is made of a polymer organic material. The resulting alignment film is irradiated with an ion beam in a vacuum from obliquely above the alignment film surface, and then the surface of the alignment film is rubbed with a rubbing material in substantially the same direction as the previous ion beam irradiation direction. It is characterized by doing.

A second alignment treatment method of the present invention is for aligning liquid crystal molecules formed on a substrate, and the surface of an alignment film made of a high molecular organic material is unidirectionally moved by using a rubbing material. Then, the alignment film is irradiated with an ion beam obliquely above the alignment film surface in a substantially same direction as the rubbing direction of the rubbing material.

[0011]

According to the first alignment treatment method, the molecular structure of the alignment film is divided by the energy of the ion beam by irradiating the alignment film with the ion beam.
Even if it is difficult to perform the rubbing treatment on the alignment film, the rubbing treatment can be easily performed. Therefore, after that, by subjecting the same alignment film to a rubbing treatment, a high alignment property can be obtained even in an alignment film that is difficult to perform a rubbing treatment.

In this case, if the ion beam irradiation direction and the rubbing direction are made substantially the same and the ion beam is irradiated obliquely from above the alignment film surface, the alignment property is further improved.

According to the second alignment treatment method, by subjecting the alignment film to the rubbing treatment, it is possible to obtain some degree of orientation even if the alignment film is difficult to perform the rubbing treatment. After that, by irradiating the same alignment film with an ion beam, the molecular structure of the alignment film is divided by the energy of the ion beam, and the divided polymers are further aligned in a certain direction. High orientation can be obtained even in an orientation film that is difficult to be treated.

Also in this case, if the rubbing direction and the ion beam irradiation direction are substantially the same and the ion beam is irradiated obliquely from above the alignment film surface, the alignment property is further improved.

[0015]

EXAMPLE A rubbing process for an alignment film is performed, for example, with reference to FIG.
It is performed using a device as shown in. This apparatus has a moving table 20 that moves in a certain direction, for example, the direction of arrow A, and the alignment film-attached substrate 2 to be subjected to the alignment treatment is placed thereon.

In this example, the substrate 2 with an alignment film is formed by coating the surface of a glass substrate 4 with an alignment film 6 made of a high molecular weight organic material such as polyimide, for example, a high molecular weight organic material which is difficult to be rubbed as described above. It was done. In the case of configuring a liquid crystal display, a transparent electrode made of ITO (tin-doped indium oxide) or the like is formed between the glass substrate 4 and the alignment film 6.

The rubbing material 2 is provided above the moving table 20.
2 is provided, and the moving table 20 is moved to the arrow A, for example.
By moving in the direction, the surface of the alignment film 6 of the substrate with alignment film 2 can be rubbed (rubbed) by the rubbing material 22 in the direction opposite to the arrow A when viewed relatively.

The rubbing material 22 is the roller 2 in the illustrated example.
Although it is a rubbing cloth made of nylon, rayon or the like and wound around the outer periphery of 4, it may be a brush-like cloth made of the same material. The rubbing material 22 in this example is normally rotated in the direction opposite to the movement of the moving table 20, as indicated by arrow B.

Irradiation of the ion beam onto the alignment film 6 is performed by using, for example, a device as shown in FIG. This device
The holder 8 is provided in a vacuum container (not shown) and holds the alignment film-attached substrate 2 to be subjected to the alignment treatment. In this example, the holder 8 can be reciprocally rotated about the rotation axis 10 as indicated by an arrow C so that the irradiation angle θ of the ion beam 14 with respect to the surface of the alignment film 6 can be changed. Above the holder 8, an ion source 12 that irradiates the alignment film 6 of the substrate 2 with an alignment film on the holder 8 with an ion beam 14 and a filament 16 that supplies electrons 18 to the alignment film 6 are provided. . By using such a device, the ion beam 14 extracted from the ion source 12 in a vacuum of, for example, about 3 × 10 ⁻⁵ Torr.
The alignment film 6 is irradiated with.

As the ion beam 14, an inert gas ion beam of, for example, helium, neon, argon or the like is used so that the ions do not react with the alignment film 6 and change the properties of the alignment film 6. preferable. In the examples below, an argon ion beam was used.

The acceleration energy of the ion beam 14 is not particularly limited and may be about 100 eV to 500 eV, for example. The following examples also set this range.

When the alignment film 6 is irradiated with the ion beam, at the same time, the electrons 18 extracted from the filament 16 are supplied to the alignment film 6 to cause the ion beam 14 to move.
It is preferable to neutralize the positive charge due to. This is because if positive charges due to the ion beam 14 are accumulated on the surface of the alignment film 6, it interferes with the flight of the ion beam 14 and the treatment of the alignment film 6 becomes difficult or uneven.
Furthermore, when the liquid crystal cell is formed after the alignment treatment, the residual charge disturbs the alignment of the liquid crystal molecules, which can be prevented by supplying electrons.

In the orientation treatment, the ion beam 14 is used.
Irradiates the surface of the alignment film 6 obliquely from above, that is, with the irradiation angle θ shown in FIG. 2 being an acute angle. The smaller the irradiation angle θ, the greater the degree of alignment order of the liquid crystal. Therefore, the irradiation angle θ is preferably smaller, and more preferably 50 degrees or less. The degree of orientational order indicates what proportion of liquid crystal molecules are oriented in the same direction, and is 100% in the case of 1. The smaller the irradiation angle θ is, the larger the orientation order is. The smaller the irradiation angle θ is, the stronger directionality can be given to the arrangement of the polymers forming the alignment film 6, or the alignment is performed by the sputtering by the ion beam irradiation. It is considered that this is because a large number of minute grooves formed on the surface of the film 6 become elongated in the ion beam irradiation direction.

Further, as shown in FIG. 3, the ion beam irradiation direction E to the alignment film 6 and the rubbing direction D to the alignment film 6 (that is, the moving direction A of the moving table 20 in FIG. 1).
(In the opposite direction), even if any processing is performed first, the directions are substantially the same (including the same direction). this is,
This is because it is preferable to make them substantially the same direction in order to obtain a higher alignment property, because the two processing directions for the same alignment film 6 are aligned to reinforce each other's alignment processing.

FIG. 5 is a diagram showing an example of the measurement result of the azimuth angle when only the rubbing treatment is applied to the alignment film which is difficult to perform the rubbing treatment. In this example, this alignment film is made of soluble polyimide in which the number n of monomer units is 1000 or more. As shown in FIG. 4, the distance on the horizontal axis is the distance in the rubbing direction of the alignment film 6, and the azimuth angle φ on the vertical axis is shown in FIG.
As shown in, the rubbing direction D and the alignment direction F of the liquid crystal molecules are
And the clockwise direction is negative here (the same applies to FIGS. 6 and 7).

It can be said that the smaller the fluctuation of the azimuth angle φ, that is, the more uniform the azimuth angle φ, the higher the orientation of the alignment film 6. However, as can be seen from FIG. Is so large that sufficient orientation cannot be obtained.

When the alignment film 6 which is hard to be subjected to such a rubbing treatment is irradiated with the ion beam 14 using the apparatus shown in FIG. 2 and then subjected to the rubbing treatment using the apparatus shown in FIG. The measurement result of the azimuth angle φ of is shown in FIG. At this time, the irradiation angle θ was set to 30 degrees. Also,
The ion beam irradiation direction E and the rubbing direction D were the same direction.

As can be seen from FIG. 6, the fluctuation of the azimuth angle φ is very small, and the high orientation of the orientation film 6 which was not sufficiently oriented by the rubbing treatment only by the irradiation of the ion beam precedes. You can get sex. Incidentally, FIG. 7 shows the measurement results of the azimuth angle φ when only the rubbing treatment is applied to the alignment film which is easily subjected to the rubbing treatment. According to this example, the same orientation as that in the case of FIG. 7 is obtained. I was able to.

In addition, the alignment film 6 having the azimuth angle characteristics as shown in FIG. 5 which is hard to be subjected to the rubbing treatment is subjected to the rubbing treatment using the apparatus shown in FIG. Irradiation with the ion beam 14 was performed using the apparatus shown. At this time, the irradiation angle θ was set to 30 degrees. Also,
The rubbing direction D and the ion beam irradiation direction E were the same direction.

As a result, the degree of orientation order of the orientation film 6 is
It was 0.8 when only rubbing treatment was applied,
In this example, it was improved to 0.92, and high orientation could be obtained.

[0031]

As described above, according to the present invention, the ion beam irradiation and the rubbing treatment are used together, the ion beam irradiation direction and the rubbing direction are substantially the same, and the ion beam is obliquely directed to the alignment film surface. Since the irradiation is performed from above, the rubbing treatment can be effectively performed even on the alignment film that is difficult to be subjected to the rubbing treatment, and high orientation can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus for rubbing an alignment film.

FIG. 2 is a schematic view showing an example of an apparatus for irradiating an alignment film with an ion beam.

FIG. 3 is a plan view showing an example of a relationship between a rubbing direction and an ion beam irradiation direction.

FIG. 4 is a plan view for explaining an azimuth angle.

FIG. 5 is a diagram showing an example of a measurement result of an azimuth angle when only the rubbing treatment is applied to the alignment film which is difficult to perform the rubbing treatment.

FIG. 6 is a diagram showing an example of measurement results of azimuth angles when a rubbing process is performed after irradiating the same alignment film as in FIG. 5 with an ion beam.

FIG. 7 is a diagram showing an example of measurement results of azimuth angles when only an rubbing treatment is applied to an alignment film which is easily subjected to the rubbing treatment.

[Explanation of symbols]

 2 substrate with alignment film 4 glass substrate 6 alignment film 12 ion source 14 ion beam 20 moving table 22 rubbing material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Asagi, 47 Umezu Takaunemachi, Ukyo-ku, Kyoto City, Kyoto Prefecture Nissin Electric Co., Ltd. Electric Co., Ltd.

Claims (2)

[Claims] 1. An alignment film formed on a substrate for aligning liquid crystal molecules, which is provided with an ion beam in a vacuum from an alignment film made of a polymer organic material, obliquely above the alignment film surface. An alignment treatment method for an alignment film, which comprises irradiating and then rubbing the surface of the alignment film with a rubbing material in substantially the same direction as the previous ion beam irradiation direction. 2. A surface of an alignment film formed on a substrate for aligning liquid crystal molecules and made of a high molecular organic material is rubbed in a certain direction with a rubbing material,
After that, an ion beam is applied to the alignment film in a vacuum from obliquely above the alignment film surface, and in a direction substantially the same as the rubbing direction of the rubbing material described above. .