JP2007127897A - Method of manufacturing anisotropic optical film, anisotropic optical film, and optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an anisotropic optical film which has a high dichroic ratio without any optical defects, and also has an alignment direction different from a coating direction even while coating a base material almost in parallel to the subsreate (in a direction almost matched with a longitudinal direction or a lateral direction of the base material). <P>SOLUTION: When the film of an anisotropic optical material is formed by a wet film-forming method using the composition for forming the optical film, an alignment treatment direction of a substrate of the base material 10 is made to be an angle between 89° and 1° from the base material and the composition for forming the optical film is applied by moving a slot die 11 being an applicator almost in parallel to a base material direction of the base material 10. Thereby the anisotropic optical film which has alignment with an angle between 85° and 5° from the alignment treatment direction of the base material, is obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an anisotropic optical film and a manufacturing method, and more particularly to an anisotropic optical film having an orientation direction different from a coating direction and a manufacturing method thereof.

In an LCD (liquid crystal display), a linearly polarizing plate and a circularly polarizing plate are used to control optical rotation and birefringence in display. Also in OLED (organic EL element), a circularly polarizing plate is used to prevent reflection of external light.
Conventionally, in these polarizing plates (polarizing elements), iodine or an organic dye having dichroism is dissolved or adsorbed in a polymer material such as polyvinyl alcohol, and the film is stretched in a film shape in one direction. Polarizing elements obtained by orienting dichroic dyes have been widely used. However, the conventional polarizing element manufactured in this way has a problem that heat resistance and light resistance are not sufficient depending on the dye or polymer material used. Another problem is that the yield of the bonding of the films during the production of the liquid crystal device is poor.

Therefore, in the prior art described in the publication, the dichroic dye is oriented by a mechanical force such as a shearing force when applying a solution containing the dichroic dye on a substrate such as glass or a transparent film. Thus, a method for producing a polarizing film has been studied (for example, see Patent Document 1). However, the polarizing film obtained by this method is oriented in the same direction as the coating direction. For example, in order to obtain a rectangular chip having a polarization axis direction of 45 degrees that is normally used, a polarization axis of 45 degrees is used. There was a problem that the yield was very bad because it had to be processed in the direction.
Therefore, as a technique described in other publications, a method of applying a solution obliquely to a substrate by a bar coating method has been proposed (for example, see Patent Documents 2 and 3).

JP-T 8-511109 JP 2002-90526 A JP 2002-180052 A

  As described above, according to the coating methods described in Patent Documents 2 and 3, for example, the 45-degree long polarizing plate in the polarization axis direction can be produced by the bar coating method. However, this bar coating method has a problem in that a vertical stripe-like defect appears or unevenness due to rotational fluctuation occurs due to rotation of the bar. In addition, the structure of the apparatus is complicated and expensive in order to cope with a single substrate. Furthermore, when the coating tool protrudes at the beginning and end of application, there is a problem that the application becomes unstable and defects such as uneven alignment occur. In particular, in the case of a single wafer substrate, a problem of defects such as uneven alignment appears remarkably. Therefore, there is a problem in applying this bar coating method to actual production.

  The present invention has been made to solve the technical problems as described above, and the object of the present invention is to produce an anisotropic optical film having an orientation direction different from the coating direction in a high production. There is to manufacture with sex.

As a result of intensive studies by the present inventors, when forming an anisotropic optical film by a wet film forming method using the composition for forming an optical film, the orientation treatment direction of the base of the substrate is 89 degrees from the substrate. By applying the optical film-forming composition at an angle of ˜1 ° and substantially parallel to the substrate, the angle is 85 ° to 5 ° from the orientation processing direction of the base, having a high dichroic ratio and no optical defects. As a result, it was found that an anisotropic optical film oriented with the above can be obtained, and the present invention has been achieved.
Here, it is estimated that the reason why an anisotropic optical film having an orientation direction different from the coating direction and the orientation direction of the base can be obtained is as follows. After forming the anisotropic optical film in a direction different from the orientation direction of the foundation, the anisotropic optical film is oriented in the orientation direction of the foundation in the lower layer of the film, and the anisotropic optical film is oriented in the coating direction in the upper layer of the film, It is considered that the orientation direction of the anisotropic optical film changed over time between the orientation direction of the base and the coating direction.

  That is, the present invention relates to a method for producing an anisotropic optical film formed by applying a composition for forming an optical film on a substrate that has been oriented in one direction, and is directed to the direction of orientation treatment on the substrate. On the other hand, the application direction is an angle that is not parallel. In this way, the base material is previously subjected to an orientation treatment different from the base material direction, and for example, by applying in parallel to the base material direction, the direction in which the dye molecules are arranged (polarization axis) is changed to the coating direction (base material direction). Can be in a different direction.

Here, the “non-parallel angle” can be characterized in that the coating direction is an angle of 89 degrees to 1 degree with respect to the orientation processing direction on the substrate. Further, depending on how the angle is set, the angle can be set to 359 degrees to 271 degrees, 269 degrees to 181 degrees, and 179 degrees to 91 degrees.
Moreover, if this application direction is characterized by being parallel to the substrate direction, it is preferable in that, for example, productivity can be improved.
Furthermore, the composition for forming an optical film may be formed by applying an anisotropic optical material solution such as a dye solution in a liquid crystal phase.
Still further, the substrate may be a single substrate.

  In addition, this invention is applicable also to the anisotropic optical film manufactured by these manufacturing methods.

  On the other hand, the present invention is an anisotropic optical film formed by applying a composition for forming an optical film on a substrate that has been oriented in one direction, and the orientation direction of the anisotropic optical film is: It is located at an intermediate angle between the orientation processing direction of the substrate and the coating direction, and the orientation direction of the anisotropic optical film is an angle of 85 to 5 degrees with respect to the coating direction. Can do.

  From another point of view, the present invention is an anisotropic optical film formed by applying a composition for forming an optical film on a substrate that has been oriented in one direction. The orientation direction of the film is located between the orientation direction of the base material and the base material direction, and the orientation direction of the anisotropic optical film is at an angle of 85 to 5 degrees with respect to the base material direction. It can be characterized by being.

  From another point of view, the anisotropic optical film to which the present invention is applied is characterized in that the angle between the polarization axis at the time of incidence and the polarization axis at the time of emission is 89 degrees to 1 degree. it can.

  These anisotropic optical films can be characterized by having a phase difference function and a polarization function.

  Further, the present invention can be applied to optical elements having these anisotropic optical films.

According to the present invention, while applying substantially parallel to the base material (direction substantially coincident with the vertical or horizontal direction of the base material), there is no optical defect and the dichroic ratio is high, and the orientation direction is different from the application direction. An anisotropic optical film having the same can be obtained.
In addition, since the orientation direction can be controlled by the film thickness direction by changing the angle between the orientation direction and the coating direction, the film thickness, drying conditions, etc., for example, improved viewing angle characteristics, optical rotation, phase difference performance, It can be expected to have polarization or elliptic polarization.
Furthermore, it can be applied substantially parallel to the substrate, and after application, it is not necessary to cut out the substrate in order to have a necessary polarization angle, and the productivity is high.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The description of the constituent requirements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents.

Here, the anisotropic optical film referred to in the present invention differs from the electromagnetic properties in any two directions selected from a total of three directions in the three-dimensional coordinate system of the film thickness direction and any two orthogonal in-plane directions. It is an optical film having a directivity. Examples of electromagnetic properties include optical properties such as absorption and refraction, and electrical properties such as resistance and capacitance. Examples of the film having optical anisotropy such as absorption and refraction include a linearly polarizing film, a circularly polarizing film, a retardation film, and a conductive anisotropic film. That is, the anisotropic optical film of the present invention is preferably used for a polarizing film, a retardation film, and a conductive anisotropic film, and more preferably used for a polarizing film.
Here, the anisotropic optical film of the present invention is usually produced by a wet film formation method. The wet film-forming method referred to in the present invention refers to a method obtained by applying a coating solution on a substrate and orienting and / or laminating a compound (pigment) contained in the coating solution.

(Base material)
Examples of the base material include glass, triacetate, acrylic, polyester, triacetyl cellulose, norbon-based, cyclic polyolefin-based, and urethane-based films. It may be a single substrate or a film-like substrate. Also, since a rectangular polarizing plate having a polarization axis of 45 degrees is usually obtained by cutting, there is no need to cut out the base material to give the necessary polarization angle after coating, and the cutting process is performed. A single-wafer substrate is preferable because it can save productivity and improve productivity. Moreover, as a film thickness of a base material, it is 0.01 mm or more normally, Preferably it is 0.02 mm or more, Usually 3 mm or less, Preferably it is 1 mm or less.
In the present invention, the base material direction is the unwinding or winding direction in the case of a long base material, and the longitudinal direction or short side direction of a rectangle in the case of a single substrate.

(Orientation treatment)
In order to control the orientation direction of the compound (pigment), a known method described in “Liquid Crystal Handbook” (Maruzen Co., Ltd., issued on October 30, 2000), pages 226 to 239, etc. Thus, an orientation process is performed in one direction. In the present invention, this orientation-treated direction is referred to as an orientation treatment direction. Specifically, there is a method of providing directionality after forming a uniform thin film on the surface of the substrate. Or there exists the method of forming a thin film, providing directionality to the base-material surface.

  In the former, a polyamic acid monomer, a photocurable resin monomer, a polymer such as polyester, which is a polyimide precursor monomer, is applied in a solution state, and a uniform thin film is formed by post-treatment such as drying. Further, there is a method of imparting directivity to the whole or a part of the thin film surface by rubbing the thin film with a rayon cloth or the like, or irradiating electromagnetic waves such as ultraviolet rays or electron beams.

In the latter case, the polymer substrate is uniaxially formed by obliquely depositing silicon oxide on the substrate surface, rubbing a resin piece such as PTFE on the substrate surface in one direction, and transferring the resin thin film to the substrate surface. Stretching in the direction.
Specifically, on a glass substrate (eg, Asahi Glass AN100, thickness 0.7 to 1.1 mm), a polyamic acid (eg, Nissan Chemical's Sunever 150, etc.) is silk-printed as a base layer, A film (500 nm to 2000 nm) formed by a spin coating method or a slot die coating method is preheated at 100 to 150 ° C., and a copolymerization reaction is performed at 200 to 300 ° C. to obtain a polyimide film. As the underlayer, polyester, PVA, polyacetate, or the like can be used. A roll (for example, a diameter of 30 to 30 mm) in which a substrate with the base layer is fixed and a rubbing cloth (eg, polyethylene, rayon, cotton) is wound on the substrate with a certain amount of pushing (for example, 0.2 to 1 mm). 100 mm) is pressed and the roll is rotated (for example, 100 to 5000 rpm) while moving the substrate (for example, 3 to 500 mm / s), whereby an alignment-treated film of a polyimide film can be obtained. As another method for forming the alignment layer, there is an oblique deposition film of silicon dioxide or a vacuum deposited film of diamond-like carbon, which is irradiated with an ion beam.
Particularly preferred is a rayon rubbing cloth (YA-20R) wound on a 46 mm diameter roll on polyimide made by preheating Hitachi Chemical LX-1400 at 120 ° C. for 0.5 hour and firing at 260 ° C. for 1 hour. What was rubbed was used under the conditions of a push-in amount of 0.4 mm, a substrate feed speed of 7.5 mm / s, and a roll rotation speed of 1000 rpm.

(Composition for optical film formation)
In the present invention, an anisotropic optical film is produced by applying an optical film-forming composition onto a substrate that has been oriented in one direction. The material to be applied (optical film forming composition) may be a material containing an organic compound that can constitute the optical film, and may be a solution or a gel material.
Specifically, a dye composition containing a dye is preferable, and a dye solution is particularly preferable. By using a dichroic dye, an anisotropic optical film can be used as a polarizing film. Hereinafter, as a preferred embodiment of the present invention, an example in which an anisotropic optical film is produced using a dye solution will be described. The dye solution usually contains a dye and a solvent. The dye solution is preferably in a liquid crystal phase because of the high degree of orientation of the dye film from which the solvent has evaporated. Here, in the present invention, the state of the liquid crystal phase refers to the state described on pages 1 to 16 of “Basics and Applications of Liquid Crystals” (Shinichi Matsumoto, Ryo Tsunoda, 1991). . In particular, the nematic phase described on page 3 is preferred.

(Dye)
As the dye, a dichroic dye is usually used. The dye is preferably a dye having a liquid crystal phase for alignment control. Here, the dye having a liquid crystal phase means a dye exhibiting lyotropic liquid crystallinity in a solvent.
Specific examples of the dye include azo dyes, stilbene dyes, cyanine dyes, phthalocyanine dyes, and condensed polycyclic dyes (perylene and oxazine dyes). Among these dyes, azo dyes that can take a high molecular arrangement in the anisotropic optical film are preferable.
An azo dye means a dye having at least one azo group. The number of azo groups in one molecule is preferably 2 or more, preferably 6 or less, more preferably 4 or less, from the viewpoint of color tone and production.

As the dye, a dye represented by the following formula (1) is preferable.

In the above equation (1),
A represents a phenylene group which may have a substituent or a naphthylene group which may have a substituent.
R ₁ represents a hydrogen atom, a hydroxyl group or an alkoxy group which may have a substituent.
R ₂ and R ₃ each independently represent a hydrogen atom, an alkyl group that may have a substituent, or a phenyl group that may have a substituent.
n represents 0 or 1.
X represents 1 or 2.
When X is 2, a plurality of A contained in one molecule may be the same or different.

Moreover, the pigment | dye represented by following formula (2) is also preferable.

In the above formula (2),
B represents a phenylene group which may have a substituent or a naphthylene group which may have a substituent.
R ₄ represents a hydrogen atom, a hydroxyl group or an alkoxy group which may have a substituent.
R ₅ and R ₆ represent a hydrogen atom, an alkyl group which may have a substituent, or a phenyl group which may have a substituent.
m represents 0 or 1.
Y represents 1 or 2.
When Y is 2, the plurality of B contained in one molecule may be the same or different.

Furthermore, the pigment | dye represented by following formula (3) is also preferable.

In the above formula (3),
D ¹ represents a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or an aromatic heterocyclic group which may have a substituent.
A ¹ represents an aromatic hydrocarbon group which may have a substituent.
R ₇ and R ₈ each independently represent a hydrogen atom, an optionally substituted alkyl group or an optionally substituted phenyl group.
p represents 0 or 1.

The term “may have a substituent” as used in the present invention means that it may have one or more substituents.
The dyes represented by the above formulas (1) to (3) of the present invention are usually water-soluble dyes and are usually dichroic dyes, depending on the number of hydrophilic groups in the molecule. .

In the formula (3), when D ¹ is an aromatic heterocyclic group which may have a substituent, examples of the hetero atom of the aromatic heterocyclic group include a nitrogen atom and a sulfur atom. In addition, an aromatic heterocyclic group having a nitrogen atom is preferable because the concentration of liquid crystallinity is lowered. Specific examples of the aromatic heterocyclic group include a pyridyl group, a quinolyl group, a thiazolyl group, and a benzothiazolyl group, and a pyridyl group is preferable.

In the formula (3), A ¹ represents an aromatic hydrocarbon group which may have a substituent. Specific examples of the aromatic hydrocarbon group include a phenylene group and a naphthylene group. The phenylene group is preferably a 1,4-phenylene group, and the naphthylene group is preferably a 1,4-naphthylene group because the dyes exhibit an interaction.

In the above formulas (1) to (3), the substituents which the phenylene group, naphthylene group, aromatic hydrocarbon group or aromatic heterocyclic group of A, B, D ¹ and A ¹ may have. Includes an alkyl group, an alkoxy group, an amino group, an acyl group, a carbamoyl group, a carboxy group, a sulfo group, a hydroxyl group and a cyano group. In particular, a hydrophilic group introduced to enhance the solubility of the dye, an electron donating group introduced to adjust the color tone, or a group having an electron withdrawing property are preferable. These substituents may further have a substituent, and examples thereof include an alkyl group, an alkoxy group, an amino group, an acyl group, a carbamoyl group, a carboxy group, a sulfo group, a hydroxyl group and a cyano group.

Specifically, an alkyl group (preferably having 1 to 4 carbon atoms) which may have a substituent such as a methyl group, an ethyl group, an n-propyl group, a hydroxyethyl group, or a 1,2-dihydroxypropyl group. Alkyl group);
An alkoxy group (preferably having 1 to 4 carbon atoms) which may have a substituent such as a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, a hydroxyethoxy group, or a 1,2-dihydroxypropoxy group An alkoxy group);
In addition, alkylamino groups such as methylamino group, ethylamino group, propylamino group, and dimethylamino group (preferably an amino group substituted with an alkyl group having 1 to 4 carbon atoms); phenylamino group; acetyl group, benzoyl group An amino group optionally having a substituent such as an acylamino group (preferably an amino group substituted with an acyl group having 2 to 7 carbon atoms);
Substituted carbamoyl groups such as a phenylaminocarbonyl group and a naphthylaminocarbonyl group;
A carboxy group;
A sulfo group;
Hydroxyl group;
And a cyano group.

Of these substituents, preferred are a sulfo group, a hydroxyl group and a carboxy group.
In the above formulas (1) to (3), when R ₂ , R ₃ , R _{5 to} R ₈ are alkyl groups, the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group may have a substituent.
When R ₁ and R ₄ in the formulas (1) to (2) are alkoxy groups, the alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms. The alkoxy group may have a substituent.
In the formulas (1) to (3), examples of the substituent that the alkyl group, alkoxy group, or phenyl group of R _{1 to} R ₈ may have include a hydroxyl group, a carboxy group, and a sulfo group.
The molecular weight of the dyes represented by the formulas (1) to (3) is preferably 450 or more, preferably 1500 or less, more preferably 1100 or less in the form of a free acid.
The dyes represented by the formulas (1) to (3) are suitable as dyes for anisotropic dye films formed by a wet film forming method, have low wavelength dispersion, and have a high dichroic ratio. Therefore, an anisotropic dye film showing a high degree of molecular orientation can be obtained using the dye.
Therefore, if a dye composition using the dye is used for the anisotropic dye film, an anisotropic dye film having high polarization characteristics can be obtained.

  The dye used in the present invention may be used in the form of a free acid as represented by the above formulas (1) to (3), and a part of the acid group has a salt form. May be. Further, a salt-type dye and a free acid-type dye may be mixed. Moreover, when it is obtained in a salt form at the time of production, it may be used as it is or may be converted into a desired salt form. As a salt type exchange method, a known method can be arbitrarily used, and examples thereof include the following methods.

1) A strong acid such as hydrochloric acid is added to an aqueous solution of a dye obtained in a salt form, the dye is acidified in the form of a free acid, and the dye is then added with an alkaline solution having a desired counter ion (for example, an aqueous lithium hydroxide solution). A method of neutralizing acidic groups and salt exchange.
2) A method of performing salt exchange in the form of a salting-out cake by adding a large excess of a neutral salt (for example, lithium chloride) having a desired counter ion to an aqueous solution of a dye obtained in a salt form.
3) An aqueous solution of a dye obtained in a salt form is treated with a strongly acidic cation exchange resin, and the dye is acidified in the form of a free acid, and then an alkali solution having a desired counter ion (for example, an aqueous lithium hydroxide solution) ) To neutralize the acidic group of the dye and perform salt exchange.
4) A method of performing salt exchange by causing an aqueous solution of a dye obtained in a salt form to act on a strongly acidic cation exchange resin previously treated with an alkaline solution having a desired counter ion (for example, an aqueous lithium hydroxide solution).

In the dye used in the present invention, whether the acidic group takes a free acid form or a salt form depends on the pKa of the dye and the pH of the dye aqueous solution.
Examples of the salt type include salts of alkali metals such as Na, Li and K, ammonium salts which may be substituted with alkyl groups or hydroxyalkyl groups, and organic amine salts. Examples of the organic amine include a lower alkyl amine having 1 to 6 carbon atoms, a hydroxy substituted lower alkyl amine having 1 to 6 carbon atoms, a carboxy substituted lower alkyl amine having 1 to 6 carbon atoms, and the like. In the case of these salt types, the type is not limited to one type, and a plurality of types may be mixed.

  Preferred examples of the dyes represented by formulas (1) to (3) of the present invention in the form of a free acid include, but are not limited to, dyes having the structure shown below.

  In the present invention, the above-described dyes can be used alone, but two or more of these may be used in combination, and dyes other than the above exemplified dyes are blended and used to such an extent that the orientation is not lowered. Thus, anisotropic dye films having various hues can be produced.

Examples of blending dyes when blending other dyes include C.I. I. Direct Yellow 12, C.I. I. Direct Yellow 34, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 142, C.I. I. Direct
Yellow 132, C.I. I. Acid Yellow 25, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Orange 79, C.I. I. Acid Orange 28, C.I. I. Direct Red 39, C.I. I. Direct Red 79, C.I. I. Direct
Red 81, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Acid Red 37, C.I. I. Direct Violet 9, C.I. I. Direct Violet 35, C.I. I. Direct Violet 48, C.I. I. Direct Violet 57, C.I. I. Direct Blue 1, C.I. I. Direct Blue 67, C.I. I. Direct Blue 83, C.I. I. Direct Blue 90, C.I. I. Direct Green 42, C.I. I. Direct Green 51, C.I. I. Direct Green 59 etc. are mentioned.

(solvent)
As the solvent, water, a water-miscible organic solvent, or a mixture thereof is suitable. Specific examples of the organic solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and glycerin, glycols such as ethylene glycol and diethylene glycol, cellosolves such as methyl cellosolve and ethyl cellosolve, or a mixture of two or more. A solvent is mentioned.

(concentration)
The concentration of the dye in the dye solution is usually 0.01% by weight or more, particularly preferably 0.1% by weight or more, and usually 50% by weight or less, particularly preferably 30% by weight or less. If the dye concentration is too low, sufficient optical transparency and dichroism cannot be obtained in the obtained anisotropic dye film, and if it is too high, the dye may precipitate in the dye solution.

(Additive)
The dye solution may further contain additives such as a surfactant and a pH adjuster as necessary. Additives can improve wettability and coatability.
As the surfactant, any of anionic, cationic and nonionic properties can be used. The concentration of the additive is sufficient to obtain the desired effect, and the concentration in the dye solution is usually 0.05% by weight or more and 0.5% by weight or less as an amount that does not inhibit the orientation of the dye molecules. .
In addition, for the purpose of suppressing instability such as salt formation and aggregation of the dye in the dye solution, generally known pH adjusters such as acids and alkalis are mixed before and after mixing the components of the dye solution. Alternatively, the pH may be adjusted by adding either during mixing.
Furthermore, as additives other than those described above, known additives described in “Additive for Coating”, Edited by J. Bieleman, Willey-VCH (2000) can also be used.

(Application)
FIG. 1 is a diagram for explaining a method of manufacturing an optical film to which the present embodiment is applied. In the case of manufacturing an anisotropic optical film using a slot die coating method, the orientation processing direction and the coating direction are illustrated. Showing the relationship.
In the manufacturing method shown in FIG. 1, a slot die (die) 11 that is an applicator and a base material 10 are relatively moved in the coating direction in the figure on a base material 10 that has been subjected to an orientation treatment in one direction. As a result, the dye solution is applied to produce an anisotropic optical film. In the present embodiment, grooves are first formed in the base material 10 by rubbing treatment, and orientation treatment is performed. The direction of this orientation treatment is an angle that is not parallel to the direction of the base material 10 (the direction that substantially matches the vertical or horizontal direction of the base material 10). Then, by applying the optical film forming composition by relatively moving the slot die 11 and the base material 10 substantially parallel to the direction of the base material 10, the angle between the orientation processing direction and the coating direction is applied. (Θ) is a non-parallel angle that is neither 0 degrees nor 90 degrees. Thereby, the direction (polarization axis) in which the dye molecules are arranged can be set to a direction different from the coating direction.

The coating method using FIG. 1 will be described in more detail.
The angle (θ) shown in FIG. 1, that is, the orientation processing direction and the application direction of the base material 10, is an angle (θ) of 1 degree to 89 degrees, 91 degrees to 179 degrees, 181 degrees to 269 degrees, 271 degrees to 271 degrees. The said dye solution is apply | coated with respect to the orientation processing direction of the base material 10 so that it may become an angle except a parallel and perpendicular | vertical of 359 degree | times.
Here, the application direction refers to a direction in which the base material 10 moves relative to the application tool when the application tool does not have a peripheral speed like the slot die 11 or the blade.

  The above-mentioned angles are more preferably 5 to 85 degrees, 95 to 175 degrees, 185 to 265 degrees, and 275 to 355 degrees. More preferably, they are 10 to 80 degrees, 100 to 170 degrees, 190 to 260 degrees, and 280 to 350 degrees. Particularly preferred are 10 to 80 degrees and 100 to 170 degrees. Most preferably, it is 10 to 80 degrees. Exceeding the upper limit is not preferable because the orientation direction tends to be non-uniform, and if it is less than the lower limit, the orientation angle tends to be insufficient.

By setting the relationship between the orientation treatment direction of the substrate 10 and the application direction as described above, a polarization axis having a desired angle can be obtained. For example, in the case of using Compound (1) (Dye I of Example 1 described later), when it is desired to form a polarization axis having an angle of 45 degrees with respect to the coating direction, it is 80 degrees from the orientation direction of the substrate 10. Is preferably set as a condition in the coating direction.
If the application direction is parallel to the base material direction, it is not necessary to cut and it is preferable because of high productivity. Parallel to the base material direction means a state parallel to the long side or short side direction, as shown in FIG.

As a method of applying to the substrate, Yuji Harasaki “Coating Engineering” (Asakura Shoten Co., Ltd., issued on March 20, 1971) pp. 253 to 277 and Kunihiro Ichimura “Creation and Application of Molecular Cooperative Materials” (CMC Publishing Co., Ltd., issued March 3, 1998) There are known methods described on pages 118 to 149. In addition, for example, a method of applying a spin coating method, a spray coating method, a bar coating method, a roll coating method, a blade coating method, a curtain coating method, a fountain method, a dip method or the like on a substrate that has been previously subjected to an alignment treatment. Can be mentioned. Of these, the slot die coating method as shown in FIG. 1 is preferable.
In addition, the temperature at the time of application | coating on the base material of a pigment | dye solution is 0 degreeC or more and 80 degrees C or less normally, Preferably it is 40 degrees C or less. The humidity is usually 10% RH or more, preferably 30% RH or more, and usually 80 RH% or less.

(Film thickness)
The film thickness of the anisotropic optical film obtained by the production method of the present invention is usually the film thickness after drying, preferably 10 nm or more, more preferably 50 nm or more, preferably 30 μm or less, more preferably 10 μm or less. is there. If the film thickness of the anisotropic optical film exceeds 30 μm, it may be difficult to control the orientation of the dye molecules in the film, and if it is less than 10 nm, it may be difficult to obtain a uniform film thickness. It is not preferable.

(Anisotropic optical film)
The present invention also provides an anisotropic optical film formed by applying an optical film-forming composition on a substrate that has been oriented in one direction, and the orientation direction of the anisotropic optical film is based on the orientation direction. It is located between the material orientation treatment direction and the coating direction (intermediate angle direction), and the orientation direction of the anisotropic optical film is an angle of 85 to 5 degrees with respect to the coating direction. The present invention relates to an anisotropic optical film. By using such an anisotropic optical film, it is possible to obtain an optical element having an angle with an orientation axis, having no optical defects, excellent productivity and high optical performance. This anisotropic optical film can be obtained by the production method of the present invention, but is not limited thereto.

Here, the orientation direction of the anisotropic optical film means a transmission axis or an absorption axis of polarized light, and specifically, the anisotropic optical film is observed under crossed Nicols to be in two extinction positions. If there is one of the two axes between either the substrate direction or the coating direction and the substrate orientation processing direction (underlying layer orientation direction), the direction of that axis Is the orientation direction. The orientation direction of the anisotropic optical film is an angle of 85 to 5 degrees as described above, preferably 80 to 5 degrees, and more preferably 75 to 5 degrees. If the upper limit is exceeded, the orientation direction tends to be non-uniform, which is not preferable.
Further, the orientation direction of the anisotropic optical film is located between the orientation processing direction of the base material and the base material direction, and the orientation direction of the anisotropic optical film is from 85 degrees to 5 degrees with respect to the base material direction. An angle of degrees is also preferable for the same reason as described above. The preferable angle is also the same, and this anisotropic optical film can also be obtained by the production method of the present invention.
The typical angle of 85 to 5 degrees can be 175 to 95 degrees, 265 to 185 degrees, and 355 to 275 degrees. Similarly, the expression of a preferable angle (5 to 80 degrees, 5 to 75 degrees) varies depending on how to take the angle.

(Angle of incidence)
In addition, the anisotropic optical film of the present invention is characterized in that the angle formed between the polarization axis at the time of incidence and the polarization axis at the time of emission is from 89 degrees to 1 degree. By using such an anisotropic optical film, an optical element capable of rotating the polarization axis at a certain angle can be obtained. This anisotropic optical film can be obtained by the production method of the present invention, but is not limited thereto.
Here, the angle between the polarization axis at the time of incidence and the polarization axis at the time of emission is determined by preparing a linearly polarizing plate and an anisotropic optical film with known polarization axes, Next, the darkest angle when this anisotropic optical film is placed is the angle of the polarization axis at the time of incidence, the anisotropic optical film is first placed on the surface light source, and then the linear polarizing plate is placed. The angle that is sometimes darkest is the angle of the polarization axis at the time of emission. At this time, for example, the extinction position of the compound (1) can be perpendicular to the alignment treatment direction of the substrate, and therefore the angle of the polarization axis is the angle formed by the transmission axis of the linearly polarizing plate from the alignment treatment direction of the substrate.

The angle between the polarization axis at the time of incidence and the polarization axis at the time of emission is an angle of 89 degrees to 1 degree, preferably 5 degrees to 85 degrees, more preferably 10 degrees to 80 degrees. Exceeding the upper limit is not preferable because it tends to be non-uniform, and if it is less than the lower limit, the angle for rotating the polarization axis is decreased.
The 89 ° to 1 ° can be set to 179 ° to 91 °, 269 ° to 181 °, and 359 ° to 271 °. Similarly, the expression of a preferable angle (5 ° to 85 °, 10 ° to 80 °) also varies depending on how to take the angle.

(Phase difference function and polarization function)
The anisotropic optical film of the present invention preferably has both a retardation function and a polarization function. The phase difference function here refers to a function of cutting a specific wavelength by utilizing a refractive index difference between ordinary light and extraordinary light and a function of rotating an optical axis. Moreover, the polarization function said here has having linear polarization property.
The anisotropic optical film of the present invention is characterized in that an angle formed between the polarization axis at the time of incidence and the polarization axis at the time of emission is from 89 degrees to 1 degree. It can be said that the polarization axis at the time of emission is different and also has a phase difference function.

(Protective layer)
The anisotropic optical film of the present invention is used with a protective layer provided if necessary. This protective layer is formed by lamination with a transparent polymer film such as triacetate, acrylic, polyester, polyimide, triacetyl cellulose, norbon-based, cyclic polyolefin-based or urethane-based film, and is provided for practical use. .

(element)
When the anisotropic optical film of the present invention is used as a polarizing film or the like for various optical elements (display elements) such as LCDs and OLEDs, the surface of the electrode substrate or the like constituting these optical elements is subjected to an alignment treatment. The base material on which the anisotropic optical film of the present invention is directly formed or the anisotropic optical film of the present invention is formed may be used as a constituent member of these optical elements.

The anisotropic optical film of the present invention functions as a polarizing film that uses light absorption anisotropy to obtain linearly polarized light, circularly polarized light, elliptically polarized light, etc. By selecting the composition to be contained, it can be functionalized as various anisotropic films such as refractive anisotropy and conduction anisotropy, and various types of optical elements can be used for various purposes. .
The optical element of the present invention uses such an anisotropic optical film of the present invention. The optical element of the present invention is formed by forming the anisotropic optical film of the present invention on a substrate. In this case, the formed anisotropic optical film itself may be used. In addition to the protective layer as described above, layers having various functions such as an adhesive layer and an antireflection layer are laminated to form a laminate. May be used as

These layers having optical functions can be formed, for example, by the following method.
First, a layer having a function as a retardation film is subjected to a stretching process described in, for example, Japanese Patent No. 2841377, Japanese Patent No. 3094113, or a process described in Japanese Patent No. 3168850. Can be formed.
The layer having a function as a brightness enhancement film may be formed by forming a fine hole by a method as described in, for example, Japanese Patent Application Laid-Open Nos. 2002-169025 and 2003-29030, or the center of selective reflection. It can be formed by overlapping two or more cholesteric liquid crystal layers having different wavelengths.
The layer having a function as a reflective film or a transflective film can be formed using a metal thin film obtained by vapor deposition or sputtering.
The layer having a function as a diffusion film can be formed by coating the protective layer with a resin solution containing fine particles.
The layer having a function as a retardation film or an optical compensation film can be formed by applying and aligning a liquid crystal compound such as a discotic liquid crystal compound or a nematic liquid crystal compound.

  The anisotropic optical film of the present invention can be directly formed on a high heat-resistant substrate such as glass, and only a liquid crystal display or an organic EL display can be obtained because a high heat-resistant polarizing element can be obtained. In addition, it can be suitably used for applications requiring high heat resistance, such as liquid crystal projectors and in-vehicle display panels.

EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
The dichroic ratio (D) was calculated by the following equation after measuring the transmittance of the anisotropic optical film with a spectrophotometer (SolidSpec 3700 manufactured by Shimadzu Corporation) in which an iodine polarizing element was arranged in the incident optical system.
Dichroic ratio (D) = Az / Ay
Az = -log (Tz)
Ay = -log (Ty)
Tz: transmittance for polarized light in the absorption axis direction of the dye film
Ty: transmittance for polarized light in the direction of the polarization axis of the dye film

In the following, “part” means “part by weight”.
Example 1
In 78 parts of water, 21 parts of the Li salt of the following exemplified dye (I) and 1 part of the exemplified dye (II) below were stirred and dissolved to obtain a dye solution (composition for forming an optical film).

  A substrate (polyimide film thickness of about 800 mm), on which a polyimide alignment film is formed by a silk printing method on a glass substrate (75 mm × 150 mm, thickness 1 mm), is previously 30 degrees from the long side direction of the substrate with a cloth. The thing which gave the angle of this and gave the rubbing process was prepared. The above-described dye solution was applied at 235 mm / s with an applicator (manufactured by Imoto Seisakusho Co., Ltd.) having a thickness of about 0.4 μm after being applied at 235 mm / s with the substrate direction and the coating direction parallel to the long side direction of the substrate. An anisotropic optical film was obtained.

  The coating conditions were 24 to 26 ° C. and 40% RH to 60% RH. When the obtained anisotropic optical film was measured, the result as shown in FIG. From the result of FIG. 3, the orientation direction of the optical film was oriented in the direction of 16 degrees from the orientation treatment direction of the substrate, and the dichroic ratio was 43. FIG. 3 is a diagram showing the relationship between the orientation processing direction and the coating direction. The horizontal axis indicates the angle at which the substrate is disposed, and the vertical axis indicates the degree of crystal after application. FIG. 3 shows the application direction, the orientation treatment direction of the base material on the base material, and the orientation direction of the resulting anisotropic optical film. In the example of FIG. 3, the orientation direction of the anisotropic optical film is 16 degrees and the coating direction is 30 degrees when viewed from the orientation processing direction of the substrate, and the orientation direction of the anisotropic optical film is the orientation of the base. It turns out that it is located in the middle of the direction (the orientation treatment direction of the substrate) and the coating direction. Further, it can be understood that there are most crystals in the orientation direction of the anisotropic optical film.

(Example 2)
A dye solution was obtained in the same manner as in Example 1. A base material similar to that in Example 1 was prepared, and the dye solution was applied with a slot die at a rate of 6 mm / s with the base material direction and the coating direction being parallel to the long side direction of the base material. An anisotropic optical film was obtained. The substrate was oriented in a direction of 20 degrees from the orientation treatment direction of the substrate.
A linear polarizing plate with a known polarization axis (polarizing film product No. 3115820 manufactured by Tech Jam Co., Ltd.) is prepared, and the linear polarizing plate is placed on a surface light source (Bright box 5000 manufactured by King), and then obtained. The darkest angle when the obtained anisotropic optical film was placed was measured and found to be about 10 degrees (the angle of the polarization axis at the time of incidence). Further, when the anisotropic optical film was first placed on the surface light source, and then the linearly polarizing plate was placed, the darkest angle was measured and found to be about 2 degrees (polarization at the time of emission). Axis angle). That is, the angle formed between the polarization axis at the time of incidence and the polarization axis at the time of emission was about 2 degrees.

(Comparative Example 1)
A dye solution was obtained in the same manner as in Example 1. When a 75 × 75 × 0.7t size glass substrate (Corning 1757) was applied to the substrate in an oblique direction with an applicator (Imoto Seisakusho), the applicator was applied at a narrow application width at the beginning and end of application. However, the coating out of the substrate became unstable, resulting in defects such as film thickness unevenness and alignment unevenness, and the uniformity of the coating film was extremely poor.

(Comparative Example 2)
A dye solution was obtained in the same manner as in Example 1. When a 75 × 75 × 0.7t size glass substrate (Corning 1757) was applied while rotating the wire bar # 2 (Matsuo Sangyo Co., Ltd.) with an angle to the substrate direction, the wire bar There were many periodic irregularities in the vertical direction and streak-like defects along the coating direction due to the rotation unevenness of the film, and the uniformity was extremely poor.

It is a figure for demonstrating the manufacturing method of the optical film with which this Embodiment is applied. It is a figure which shows the base-material direction of the base material made into the rectangle. It is the figure which showed the relationship between the orientation process direction and the application | coating direction.

Explanation of symbols

10 ... Base material, 11 ... Slot die

Claims (11)

A method for producing an anisotropic optical film formed by applying a composition for forming an optical film on a substrate subjected to orientation treatment in one direction,
A method for producing an anisotropic optical film, wherein the coating direction is not parallel to the orientation treatment direction on the substrate.   2. The method for producing an anisotropic optical film according to claim 1, wherein the coating direction is an angle of 89 degrees to 1 degree with respect to the alignment treatment direction on the substrate.   The method for producing an anisotropic optical film according to claim 1, wherein the coating direction is parallel to the substrate direction.   The method for producing an anisotropic optical film according to any one of claims 1 to 3, wherein the optical film-forming composition is a dye solution in a liquid crystal phase.   The method for producing an anisotropic optical film according to claim 1, wherein the base material is a single-wafer substrate.   An anisotropic optical film manufactured by the method for manufacturing an anisotropic optical film according to claim 1. An anisotropic optical film formed by applying a composition for forming an optical film on a substrate that has been oriented in one direction,
The orientation direction of the anisotropic optical film is located between the orientation treatment direction of the substrate and the coating direction,
And,
An anisotropic optical film, wherein an orientation direction of the anisotropic optical film is an angle of 85 degrees to 5 degrees with respect to the coating direction. An anisotropic optical film formed by applying a composition for forming an optical film on a substrate that has been oriented in one direction,
The orientation direction of the anisotropic optical film is located between the orientation treatment direction of the substrate and the substrate direction,
And,
An anisotropic optical film, wherein an orientation direction of the anisotropic optical film is an angle of 85 degrees to 5 degrees with respect to the substrate direction.   An anisotropic optical film characterized in that an angle formed by a polarization axis at the time of incidence and a polarization axis at the time of emission is 89 degrees to 1 degree.   The anisotropic optical film according to claim 6, which has a phase difference function and a polarization function.   An optical element having the anisotropic optical film according to claim 6.

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