JPH09244025A - Orientation treatment of oriented film and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to lessen the generation of particles and to simplify treating stages by irradiating the unbaked oriented film formed on a substrate with an ion beam simultaneously with or after the impression of a magnetic field and executing the orientation treatment and curing of the oriented film by the irradiation. SOLUTION: A vacuum vessel 24 is internally equipped with a holder 8 for holding a substrate 2 with the oriented film to be subjected to the orientation treatment. The vessel is provided with a solenoid-like coil 16 which is disposed to enclose the holder 8 and impresses the magnetic field 18 from a prescribed direction on the oriented film 6 of the substrate 2 with the oriented film on the holder 8. The vessel is also provided with an ion source 20 for irradiating the oriented film 6 of the substrate 2 with the oriented film on the holder 8 with the ion beam 22. An exciting current is supplied to the coil 16 from a DC power source. The ion source 20 is arranged on nearly the central axis of the coil 16 to make the magnetic field by the coil 16 and the ion beam 22 from the ion source 20 incident on the oriented film 6 of the substrate 2 with the oriented film on the holder 8 nearly parallel with each other.

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, and an alignment treatment method for subjecting an alignment film for aligning liquid crystal molecules in a predetermined direction, and an alignment treatment method therefor. The present invention relates to an apparatus, and more specifically, to means for reducing the generation of particles and simplifying the processing steps.

[0002]

2. Description of the Related Art In order to align liquid crystal molecules in a predetermined direction on the surface of a substrate, an alignment film made of a high molecular weight organic material such as polyimide is formed on the surface of the substrate by coating or printing. There is.

In this case, if the alignment film is simply formed on 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 (or aligned) in a predetermined direction. Can not.

Therefore, conventionally, the alignment film has been subjected to the alignment treatment in the following steps.

An alignment film is formed on the substrate by coating or the like.

The alignment film is pre-baked at a predetermined temperature and time (for example, 80 to 100 ° C. for about 2 minutes).
Pre-baking before baking is, to put it simply, to make the film in a wet state uniform, to uniformly evaporate the solvent by uniform heating to obtain a uniform film surface, and to prevent bumping of the solvent to form an alignment film. This is to prevent problems such as cracks and peeling from occurring.

The alignment film after prebaking is baked at a predetermined temperature and time (for example, 200 to 250 ° C. for about 60 minutes). The firing is simply to react and cure the polymer organic material.

The alignment film is subjected to an alignment treatment by mechanically rubbing (rubbing) the surface of the alignment film after firing in a certain direction with a rubbing cloth made of nylon, rayon or the like.

[0009]

However, in the method of performing the alignment treatment on the alignment film by rubbing as described above,
Since particles (dust) are generated during the rubbing process, there is a problem in that this deteriorates the characteristics of the liquid crystal display and eventually reduces the yield.
For example, when particles are generated and adhere to the alignment film, display unevenness is caused thereby, display quality is deteriorated, and an electrically short-circuited portion is generated.

Further, in the conventional method of pre-baking and baking the alignment film, there is a problem that throughput (processing capacity per unit time) is low because the number of steps is increased accordingly.

Therefore, it is a main object of the present invention to provide an alignment treatment method and apparatus capable of reducing the generation of particles and simplifying the treatment process.

[0012]

In order to achieve the above object, an alignment treatment method according to the present invention applies an ion beam to a non-baked alignment film formed on a substrate simultaneously with or after applying a magnetic field. It is characterized in that the alignment film is irradiated, and thereby the alignment treatment and curing of the alignment film are performed.

In the unfired alignment film, the polymer constituting the alignment film is not yet imidized. Therefore, in this state, the main chain and side chains of the polymer are in a movable state, and when a magnetic field is applied to the alignment film in this state, the main chain and / or side chains of the polymer are aligned along the magnetic field. Since the liquid crystal molecules are aligned along it, the alignment film can be subjected to the alignment treatment. When the orientation film is irradiated with an ion beam in the state where the polymer constituting the orientation film is oriented by applying a magnetic field in this way, the energy of the ion beam causes the imidization of the orientation film to proceed and It can be cured in the oriented state. That is, the alignment state of the alignment film can be fixed.

As described above, since the alignment film can be subjected to the alignment treatment in a non-contact manner, the generation of particles can be reduced. Moreover, in the case of ion beam irradiation, prebake can be omitted because the bumping of the solvent is less likely to occur as in the case of firing, and since the alignment film can be cured in a shorter time than in the case of firing,
The processing steps can be simplified.

The alignment treatment apparatus according to the present invention is suitable for carrying out the above-described alignment treatment method.

[0016]

1 is a sectional view showing an example of an alignment treatment apparatus for carrying out the alignment treatment method according to the present invention.

This orientation processing apparatus has a predetermined degree of vacuum (for example, 10 ⁻⁵ to 10 ⁻⁷ To by an unillustrated vacuum exhaust apparatus).
a vacuum container 24 that is evacuated to about rr), a holder 8 that is provided in the vacuum container 24 and holds the substrate 2 with an alignment film to be subjected to an alignment treatment, and a vacuum container 24 in this example. A solenoid-shaped coil 16 that is provided so as to surround the holder 8 and applies a magnetic field (18 indicates an example of a line of magnetic force thereof) to the alignment film 6 of the substrate 2 with an alignment film on the holder 8 from a predetermined direction, and a vacuum. An ion source 20 that is attached to the container 24 and irradiates the alignment film 6 of the substrate 2 with an alignment film on the holder 8 with the ion beam 22 is provided. An exciting current is supplied to the coil 16 from a DC power supply (not shown).

In this example, the substrate 2 with an alignment film is formed by coating an alignment film 6 made of an organic polymer material such as polyimide on the surface of a glass substrate 4, and the alignment film 6 is in an unfired state. Is. In the case of configuring a liquid crystal display, it is necessary to provide IT between the glass substrate 4 and the alignment film 6.
A transparent electrode made of O (tin-doped indium oxide) or the like is formed.

In this embodiment, the ion source 20 is arranged substantially on the central axis of the coil 16, and the magnetic field generated by the coil 16 and the ion source 2 are applied to the alignment film 6 of the substrate 2 with the alignment film on the holder 8.
The ion beam 22 from 0 is made to enter substantially parallel to each other. With this configuration, the ion beam 22 is incident on the alignment film 6 along the magnetic field of the coil 16, so that the ion beam 22 can be incident on the alignment film 6 without being bent by the magnetic field, that is, without being disturbed by the magnetic field. Therefore, the alignment film can be subjected to highly uniform treatment.

The holder 8 has an ion beam 22 with respect to the surface of the alignment film 6 and the angle α formed by the alignment film 6 and the magnetic lines of force 18.
The rotation axis 10 so that the irradiation angle θ of the
Is rotatable about the center as indicated by an arrow A, that is, its inclination angle is variable. Further, in this embodiment, the alignment film 6
In order to change the incident directions of the magnetic force line 18 and the ion beam 22 with respect to the axis of rotation, the central axis 12 orthogonal to the rotation axis 10 can be rotated as shown by an arrow B (that is, in the rotation direction). However, this is not mandatory.

Further, such a holder 8 may be moved in the three-dimensional XYZ directions within the coil 16 within the range where the ion beam 22 is irradiated to the alignment film 6, and by doing so. The state of the magnetic field applied to the alignment film 6 can be changed.

The coil 16 may be provided inside the vacuum container 24 as in this embodiment or outside the vacuum container 24. When the coil 16 is provided in the vacuum container 24, a magnetic field can be efficiently applied from the vicinity of the alignment film 6, so that the coil 16 can be downsized. On the other hand, when the coil 16 is provided outside the vacuum container 24, there is no fear that the outgas from the coil 16 deteriorates the degree of vacuum in the vacuum container 24.

As the ion beam 22, an inert gas ion beam of, for example, helium, neon, or argon is used so that the ions do not react with the alignment film 6 and change the properties of the alignment film 6. preferable.

The acceleration energy of the ion beam 22 is, for example, about 100 eV to 500 eV, but is not limited to this.

When the alignment film 6 is irradiated with the ion beam, at the same time, a filament or the like (not shown) is used.
It is also possible to supply the electrons extracted from the alignment film 6 to neutralize the positive charges generated by the ion beam 22.

The method of performing the alignment treatment on the alignment film 6 using such an apparatus is as follows. That is, the substrate 2 with an alignment film having the unbaked alignment film 6 is mounted on the holder 8, and a magnetic field is applied to the alignment film 6 from the coil 16, or at the same time, the ion beam 22 is emitted from the ion source 20. Irradiate.

In the unfired alignment film 6, the polymer constituting the alignment film 6 is not yet imidized. Therefore, in this state,
The main chain and side chains of the polymer are in a movable state, and when a magnetic field is applied to the alignment film 6 in this state, the main chain and / or side chains of the polymer are aligned along the magnetic field and Since the liquid crystal molecules are aligned, the alignment film 6 can be subjected to alignment treatment.

FIG. 2 is a plan view showing a state in which macromolecules (more specifically, the main chain) 7 constituting the alignment film 6 are arranged along the lines of magnetic force 18, and FIG. It is intended to be shown.

When the orientation film 6 is irradiated with the ion beam 22 in the state where the polymer forming the orientation film 6 is oriented by applying the magnetic field as described above, the energy of the ion beam 22 causes the orientation film to be oriented. The imidization of 6 proceeds, and the polymer can be cured in an oriented state. That is, the alignment state of the alignment film 6 can be fixed.

In this way, since the alignment film 6 can be subjected to the alignment treatment in a non-contact manner, the generation of particles can be reduced. As a result, it is possible to improve the yield of the liquid crystal display and the display quality.

Moreover, in the case of ion beam irradiation, the pre-baking can be omitted because the bumping of the solvent unlike in the case of firing is less likely to occur, and in a much shorter time than in the case of firing (for example, 10 seconds). Since the alignment film 6 can be cured (to some degree), the processing steps can be simplified. As a result, the throughput is significantly improved.

Further, in the case of ion beam irradiation, the alignment film 6 is cured by the energy of the ion beam 22, so that the alignment film 6 can be cured at a lower temperature than in the case of firing. Therefore, even if a color filter or the like is formed on the substrate 2 with an alignment film, the color filter or the like is not adversely affected by deformation or deterioration due to heat.

Further, according to this alignment treatment method, the alignment film 6
It is also possible to control the orientation order and the pretilt angle depending on the strength and angle of the magnetic field applied to the substrate. 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 pretilt angle means an angle at which liquid crystal molecules rise above the surface of the alignment film.

FIG. 4 shows the measurement results of the orientation order degree when the magnitude of the magnetic flux density applied to the orientation film 6 was changed. The processing conditions at this time are as follows. Angle α between the alignment film and the magnetic force line α: 30 ° Ion beam irradiation angle θ: 30 ° (that is, the magnetic force line and the ion beam are substantially parallel to each other) Magnetic field application time: 10 seconds Ion beam irradiation time: 10 seconds Ion beam energy: 500 eV Ion beam current: 10 mA In the figure, the degree of orientational order obtained by the conventional rubbing method is also shown for comparison.

As shown in this figure, the magnetic flux density is about 0.0.
At 35 Tesla or more, a degree of orientation order of 0.7 or more, which is a satisfactory value when a liquid crystal display is constructed, was obtained. In addition, the orientation order tended to be saturated when the magnetic flux density was around 0.05 Tesla.

FIG. 5 shows the measurement results of the pretilt angle when the tilt angle of the holder 8 is changed and the angle α formed by the alignment film 6 and the magnetic force lines 18 and the ion beam irradiation angle θ (where α≈θ) are changed. . The processing conditions at this time are as follows. Applied magnetic flux density: 0.1 tesla Magnetic field application time: 10 seconds Ion beam irradiation time: 10 seconds Ion beam energy: 500 eV Ion beam current: 10 mA In the figure, a pretilt obtained by a conventional rubbing method for comparison. The corners are also shown.

As shown in this figure, the angles α and θ are
When was increased, a large pretilt angle was obtained accordingly. Particularly, a pretilt angle larger than that obtained by the conventional rubbing method was obtained at about 20 degrees or more. However, when the angles α and θ exceed 60 degrees, the pretilt angle tends to decrease. This is basically because although the main chains of the alignment film-constituting polymer are aligned along the direction of the magnetic field to increase the pretilt angle, when the angles α and θ exceed 60 degrees, the same polymer is irradiated by ion beam irradiation. It is considered that this is because the side chain of is more likely to be broken, and the pretilt angle is reduced due to the effect.

By applying a magnetic field having a uniform direction (that is, magnetic fields in which the magnetic force lines 18 are substantially parallel to each other) to the alignment film 6, the alignment direction of the polymer 7 in the plane of the alignment film 6 also follows the magnetic field. Since they are uniformly aligned, a uniform alignment treatment can be performed. On the other hand, in the alignment film 6, magnetic fields whose directions are not aligned (that is, magnetic fields in which the magnetic force lines 18 are not parallel to each other)
May be applied, for example, as shown in FIG.
A curved magnetic field in which 8 bends may be applied to the alignment film 6, and if so, the macromolecules 7 in the plane of the alignment film 6 are also arranged in various directions along the magnetic field, so that random alignment is performed. Can be realized. As a result, the degree of random alignment of the liquid crystal molecules is increased, and the viewing angle of the liquid crystal display can be widened.

[0039]

Since the present invention is configured as described above, it has the following effects.

According to the alignment treatment method of the first aspect, unlike the conventional rubbing, since the alignment film can be subjected to the alignment treatment without contact, the generation of particles can be reduced. As a result, it is possible to improve the yield of the liquid crystal display and the display quality.

Moreover, in the case of ion beam irradiation, the pre-baking can be omitted because the bumping of the solvent is unlikely to occur in the case of firing, and the alignment film is cured in a much shorter time than in the case of firing. Therefore, the processing steps can be simplified. As a result, the throughput is significantly improved.

In the case of ion beam irradiation, the alignment film is cured by the energy of the ion beam, so
The alignment film can be cured at a lower temperature than when firing is performed. Therefore, even if the color filter or the like is formed on the substrate with the alignment film, the color filter or the like is not adversely affected by heat such as deformation or deterioration.

The degree of orientational order can be controlled by the strength of the applied magnetic field, and the pretilt angle can also be controlled by the angle of the magnetic field and the ion beam incident on the orientation film.

According to the alignment treatment apparatus of the second aspect, the alignment treatment method of the first aspect can be implemented with a simple structure.

According to the third aspect of the alignment treatment apparatus, since the ion beam can be made incident on the alignment film without being disturbed by the magnetic field, it is possible to perform highly uniform treatment on the alignment film. Produce an effect.

According to the alignment treatment apparatus of the fourth aspect, at least the inclination angle of the holder is variable, so that the angle formed by the alignment film and the magnetic force line and the ion beam irradiation angle with respect to the alignment film are variable, and therefore the pretilt angle. The further effect is that the control of can be performed easily.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an alignment treatment apparatus for carrying out an alignment treatment method according to the present invention.

FIG. 2 is a plan view schematically showing the orientation of a polymer constituting an alignment film when a magnetic field is applied to the alignment film.

FIG. 3 is a cross-sectional view schematically showing the orientation of a polymer constituting an alignment film when a magnetic field is applied to the alignment film.

FIG. 4 is a diagram showing an example of a measurement result of orientation order when the magnitude of magnetic flux density applied to an orientation film is changed.

FIG. 5 is a diagram showing an example of measurement results of a pretilt angle when an angle α formed by an alignment film and a magnetic force line and an ion beam irradiation angle θ are changed.

FIG. 6 is a plan view schematically showing the orientation of an alignment film-constituting polymer when a curvature magnetic field is applied to the alignment film.

[Explanation of symbols]

 2 substrate with alignment film 4 glass substrate 6 alignment film 7 polymer with alignment film 8 holder 10 rotating shaft 16 coil 18 magnetic field line 20 ion source 22 ion beam 24 vacuum container

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taizo Ehara, 1164 Hino, Hino, Tokyo

Claims (4)

[Claims] 1. An unburned alignment film formed on a substrate is irradiated with an ion beam at the same time as or after a magnetic field is applied, thereby performing alignment treatment and curing of the alignment film. Alignment treatment method for an alignment film. 2. A vacuum container evacuated to a vacuum, a holder provided in the vacuum container for holding a substrate with an alignment film formed by forming an unbaked alignment film on the substrate, and a holder on the holder. An alignment treatment apparatus comprising: a coil for applying a magnetic field to the alignment film of the substrate with the alignment film and an ion source for irradiating the alignment film of the substrate with the alignment film on the holder with an ion beam. 3. The coil and the ion source are arranged so that the magnetic field and the ion beam are made to enter the alignment film of the substrate with the alignment film on the holder substantially in parallel with each other.
The alignment treatment device described. 4. The orientation processing apparatus according to claim 2, wherein at least the tilt angle of the holder is variable.