JP3163539B2 - Liquid crystalline alignment film, method for producing liquid crystalline alignment film, and optical element using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal alignment film whose alignment direction is arbitrarily controlled, a method for manufacturing the same, and an optical element using the liquid crystal alignment film.

[0002]

2. Description of the Related Art A technique for orienting molecules of an organic material or a polymer-based material is not only for improving the mechanical strength of such a material, but also for various optical elements based on optical anisotropy, for example, This is a basic technique for manufacturing a polarizing element, an optical compensation film, an optical waveguide, an optical information recording medium, and the like. The most universal method for realizing the molecular orientation of an organic / polymer-based material is to mechanically stretch a polymer fiber or film, thereby increasing the strength of the fiber or film. In addition, a phase compensator is manufactured by the stretched film, or a dye element is manufactured by orienting the dye molecules by the stretched film. However, with these mechanical methods, an arbitrary orientation direction cannot be given to an arbitrary position because a drawing force acts uniformly over the entire fiber or film. Further, even if orientation in the stretching direction is possible, orientation in a plane perpendicular to that direction cannot be controlled. Further, such a stretching treatment cannot be directly used because organic materials have no mechanical strength.

As another technique for performing molecular orientation, there is a technique utilizing a photoreaction. When linearly polarized light is applied to a liquid crystalline polymer film substituted with a photoreactive residue represented by azobenzene, azobenzene reorients in the direction defined by its polarization axis, and as a result, molecular orientation is realized. You. Therefore, it is possible to produce a material having a molecular orientation in an arbitrary direction at an arbitrary place. However, in this method, the light absorption of azobenzene contained in the alignment film itself is strong, so that its use as an optical element to be manufactured is limited.

As another method for controlling the liquid crystal alignment, a liquid crystal alignment control method utilizing a photochemical reaction on a substrate surface is known. In this method, a molecular layer or a polymer layer containing a molecule that causes an isomerization reaction by the action of light is provided on a substrate surface, and the layer is irradiated with light to control the orientation (Ichimura, Surface, 32, 671 (1994)). By irradiating the molecular layer or the polymer layer with light, a change in its molecular structure or molecular orientation is induced photochemically, which determines the orientation of the low-molecular liquid crystal. If the light is linearly polarized,
The liquid crystal can be aligned in the direction defined by the polarization axis, and homogeneous alignment control is easily realized.
(Kawanishi et al., Polym. Mater. Sci. Eng., 66, p. 263
(1992)). Further, a method has been proposed in which a film formed by dissolving and dispersing a dichroic dye in polyimide is irradiated with linearly polarized light to form a liquid crystal alignment film (Gibbons et al., Nature, 351, p4
9).

In the method of controlling the orientation of a nematic low molecular liquid crystal by a photochemical reaction on the surface of a substrate, the oriented liquid crystal has a low molecular weight and thus has no self-supporting property and is sandwiched between two substrates. For this reason, not only the production becomes complicated, but also it is extremely difficult to produce an alignment film having a uniform area and a large area. Furthermore, a method of using a liquid crystalline monomer to stabilize the alignment state by fixing low-molecular liquid crystal has been proposed, but it is necessary to produce a special monomer. However, there is a problem that it is indispensable that the substrate is sandwiched between two substrates while oxygen is blocked. As described above, in order to make the photoactive molecular layer or polymer layer provided on the substrate surface a persistent alignment film, the state of alignment with light is highly stable to heat and light, Achieving a large area with a uniform film thickness had to be solved at once.

[0006]

SUMMARY OF THE INVENTION The present invention is to stabilize the state of molecular orientation by light with respect to heat, light, and even an electric field, to achieve a large area with a uniform film thickness, The manufacturing method is not complicated, the use as an optical element is not limited, and the like are solved at once, the alignment direction can be arbitrarily controlled liquid crystal alignment film, and its manufacturing method, and the liquid crystal alignment film It is an object to provide an optical element used.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have focused on forming a self-supporting liquid crystal material on a photoreactive layer to form an alignment film, and have further studied diligently. If the resin containing dichroic photoreactive structural units shows potential liquid crystallinity or crystallinity as a result of superimposition, irradiating linearly polarized light to this type of polymer film formed from a solution Alternatively, the inventors have found that the molecular orientation state caused by light irradiation in an oblique direction can be not only significantly improved by heat treatment of the polymer film but also highly stabilized, and the present invention has been completed based on these findings. I came to.

[0008] That is, according to the present invention, a resin film having a dichroic photoreactive structural unit in a side chain, more preferably a potentially liquid crystalline or crystalline resin film is irradiated or irradiated with linearly polarized light. Non-photoreactive liquid crystal made of discotic liquid crystal or polymer liquid crystal, on which polarized light is irradiated in an oblique direction, and more preferably on a heat-treated one.
The present invention provides a liquid crystal alignment film characterized in that a non-photoreactive liquid crystal substance layer is formed by applying a solution of a liquid substance. Further, according to the present invention, there is provided an optical element characterized by using the above-mentioned liquid crystalline alignment film.
Further, according to the present invention, a potentially liquid crystalline or crystalline resin film having a dichroic photoreactive structural unit in a side chain is irradiated with linearly polarized light or non-polarized light from an oblique direction. After that, heat treatment is performed, and on the resin film, a non-light
There is provided a method for producing a liquid crystalline alignment film, which comprises forming a non-photoreactive liquid crystalline material layer by applying a solution of a reactive liquid crystalline material.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The liquid crystalline alignment film of the present invention is a resin film having a dichroic photoreactive structural unit in the side chain, more preferably a potentially liquid crystal or crystalline resin film, and is preferably a linearly polarized light irradiation or a non-polarized light. Irradiation of light in an oblique direction, and more preferably, heat treatment on the non-photoreactive liquid crystal
A non-photoreactive liquid crystal material layer is formed by applying a solution of the material. That is, the liquid crystalline alignment film of the present invention is a self-supporting alignment film, and irradiates linearly polarized light or unpolarized light from an oblique direction to a resin film having a dichroic photoreactive structural unit in a side chain. And then applying a solution of a self-supporting liquid crystalline material on the film
To form the liquid crystal material layer.

The resin film used in the present invention contains a dichroic photoreactive structural unit. Here, the term “dichroic photoreactive structural unit” refers to an absorption at the same wavelength in a molecular axis orthogonal to each other. A molecular unit having a different intensity and causing a structural change by light absorption. The dichroic photoreactive constituent unit contained in the resin film used in the present invention preferably has a rod-like structure in which intermolecular interaction occurs efficiently. Examples of such sources include azobenzene, stilbene, cinnamoyl, cinnamylidene acetate, benzylidenephthalimidine, stilbazole, stilbazolium, retinoic acid, coumarin, diphenylacetylene, and the like. Particularly preferred as such a material is a liquid crystalline or crystalline polymer substituted with an azobenzene derivative represented by the following general formula (1).

Embedded image (Where X is a divalent residue bonded to the polymer main chain, Y is a hydrogen atom, an alkyl group having up to 8 carbon atoms, a cycloalkyl group, a cyano group, a nitro group, an alkoxy group having up to 6 carbon atoms, Represents an alkoxycarbonyl group, a halogen group, a trifluoromethyl group or a trifluoromethoxy group having up to 6 carbon atoms)

The substrate used in the present invention required for providing the above resin film may be a substrate coated with such a resin, and may be transparent or opaque. For example, when forming a liquid crystal cell, Requires that at least one of the two substrates be transparent. As a transparent substrate, a sheet of silica glass, hard glass, quartz, various plastics or the like or a surface thereof, silicon oxide,
A material coated with a metal oxide such as tin oxide, indium oxide, aluminum oxide, titanium oxide, chromium oxide, or zinc oxide, silicon nitride, or silicon carbide is used. As the opaque substrate, a substrate obtained by attaching a metal layer or a metal oxide layer to the surface of a metal or glass or plastic sheet is used.

The polymer used for the resin film in the present invention is obtained by bonding or mixing the above-mentioned dichroic photoreactive structural units. Among polymers to which dichroic photoreactive structural units are bonded, a liquid crystalline or crystalline polymer which is oriented by light irradiation and is stable to heat or a solvent is preferable. The liquid crystalline or crystalline polymer can be easily identified because the film is observed by a polarizing microscope as a bright field based on birefringence. The liquid crystalline or crystalline polymer can be measured for a liquid crystal phase / isotropic phase transition temperature and a melting point by thermal analysis.

When the resin film is composed of a liquid crystalline or crystalline polymer film substituted with an azobenzene derivative, an intermolecular interaction is required in order for the azobenzene-bound polymer to exhibit liquid crystalline or crystalline properties. It is preferable to introduce an alkyl group, a cycloalkyl group, an alkoxy group, a cyano group, a nitro group, or an alkoxycarbonyl group having an enhancing effect into the azobenzene skeleton. Liquid crystallinity can also be exhibited by partially introducing a non-photoreactive mesogen group.

As the liquid crystalline polymer having azobenzene, when the main chain is polymethacrylate or polyacrylate, a polymer having a monomer unit exemplified in Table 1 below can be mentioned.

[Table 1]

In this case, it is preferred that the non-photoreactive monomer units shown in Table 2 be copolymerized units.

[Table 2]

Many examples of liquid crystal polymers having azobenzene have a main chain of polyester, polyimide, polysiloxane, polyurethane, polyurea, etc. (edited by V. Shibaev, Polymers as Electrooptica).
l and Photooptical ActiveMedia, Springer, 1996, p
37-110), and these can be used in the present invention.
Examples of the liquid crystalline azobenzene polymer used in the present invention are shown in Table 3, but are not limited thereto.

[Table 3]

Table 4 shows examples of azobenzene polymers exhibiting crystallinity.

[Table 4]

As the azobenzene polymer exhibiting crystallinity used in the present invention, the following can be used. One obtained by reacting a p-substituted azobenzene having a hydroxyalkyl group with an alternating copolymer of styrene and maleic anhydride (RH Tredgold et al., J. Phys.D: Appl.Phys., 20,
1385 (1985)) Azobenzene-substituted polyesters prepared from p-phenylenediacrylic acid (A. Natansohn et al., Macr.
omolecules, 27, 2580 (1994)). Also, polymethacrylate having cyanoazobenzene in the side chain ((1) in Table 4)
Is a crystalline polymer having a high melting point. Further, among the dichroic photoreactive structural units, cinnamoyl, cinnamylidene acetate, benzylidenephthalimidine, stilbazole, stilbazolium, coumarin, and diphenylacetylene cause a dimerization reaction by light irradiation. The molecules form a crosslinked structure after light irradiation.
For this reason, the state of alignment by light irradiation is stabilized against heat or a solvent, so that it can be suitably used in the present invention.

Next, light irradiation on a resin film having a dichroic photoreactive structural unit will be described below using a polymer having these azobenzene derivatives as an example. A solution of a polymer having azobenzene is applied to a substrate by spin coating, casting coating, screen printing, etc. to form a thin film. The film thickness is 5
nm to 1000 nm, especially 10 nm to 50 nm.
A range of 0 nm is preferred. With such a film thickness, the color of the film derived from azobenzene can be ignored, and the film is substantially colorless and transparent. Since the orientation of the self-supporting liquid crystalline substance is regulated by the orientation of azobenzene residues in the surface layer of the photoreactive polymer film, it is meaningful to control the liquid crystal orientation even if the film thickness is larger than the above range. Without
Further, coloring based on light absorption of azobenzene or substituted azobenzene cannot be neglected, and the quality of the obtained liquid crystal element deteriorates. On the other hand, if the film thickness is less than the above range, it is difficult to obtain a uniform film, and since the substrate surface is partially exposed, the uniformity of orientation of the liquid crystalline polymer is impaired.

Light irradiation methods for obtaining uniform alignment of liquid crystalline polymers include irradiation with linearly polarized light and irradiation with unpolarized light from oblique directions. In the former case, the polymer film prepared by the above method is irradiated with light from a light source through a polarizing element. As a light source, an ultra-high pressure mercury lamp, a xenon lamp, a fluorescent lamp, a mercury / xenon lamp, or the like can be used. As the polarizing element, a polyvinyl alcohol-based polarizing sheet is suitably used. Irradiation of non-polarized light in an oblique direction causes light from the above light source to enter from a direction at an angle from a perpendicular to the surface of the polymer film. The angle between the perpendicular and the incident direction is 5 to 60 degrees, more preferably 10 to 4 degrees.
5 degrees. Irradiation energy characteristics of the polymer, depends largely like illumination wavelength, 10 mJ / cm ² from 10
About J / cm ² , more preferably 50 mJ / cm ² to 2
J / cm ² . Azobenzene isomerized by irradiating ultraviolet rays with a cis-form as a main component, while irradiation with visible light causes an isomerization reaction with a trans-form as a main component. Although it is well known that the photoisomerization reaction has wavelength dependency as described above, it has been surprisingly found that both ultraviolet light and visible light can be used for light irradiation in the present invention. Therefore, in the light irradiation of the present invention, it is not necessary to separate the wavelength region,
The active wavelength light from the light source can be utilized to the maximum. In particular, in the case of ultraviolet irradiation, the amount of exposure energy required to bring about alignment may be as low as several tens mJ / cm ² .

The resin film made of a liquid crystalline or crystalline polymer in the present invention is formed by performing a heat treatment after the light irradiation. The heating temperature is lower than the melting point in the case of a crystalline polymer and lower than the liquid crystal phase-isotropic phase transition temperature in the case of a liquid crystalline polymer. By performing the heat treatment, the degree of orientation of the photoreactive molecules developed by light irradiation is significantly improved. In addition, the highly oriented state developed after the heat treatment is highly thermally stable because the molecular mobility is highly restricted by effective intermolecular interactions. Furthermore, it shows resistance to organic solvents. For example, by heating a spin-coated thin film of poly (1-methacryloyloxy-4′-cyanoazobenzene) after irradiating it with polarized light, the degree of orientation of the azobenzene group is remarkably improved. Nevertheless, the orientation was not disturbed at all. The degree of orientation did not decrease even when immersed in toluene.

The orientation of the photo-alignment film stabilized by heating does not collapse even when irradiated with light. In other words, when the heat treatment is not performed, the orientation direction can be reversibly changed by changing the linearly polarized light irradiation axis. However, the heat treatment fixes the orientation state of the azobenzene residue. By utilizing this, a stable patterned multi-axis alignment film as described below can be easily formed. That is, the polymer film thus formed is irradiated with light having different polarization axes a required number of times according to the pattern. Next, the multiaxially oriented state is fixed by heating the irradiation film. By using this polymer film as a liquid crystal alignment film, it is possible to obtain a liquid crystal alignment state in which the alignment is controlled faithfully to the azobenzene alignment, and this state is highly stable to light and heat.

In the present invention, a non-photoreactive liquid crystal material layer is provided as a self-supporting liquid crystal material layer on the resin film formed as described above. Here, "non-photoreactive" means a property that does not cause a chemical change by light irradiation, and "self-supporting property" means a property that retains its own shape unlike liquid substances. And exhibit liquid crystallinity. The formation of the non-photoreactive liquid crystal material layer is preferably performed as follows. That is, a solution of a non-photoreactive liquid crystalline substance is applied to a substrate by spin coating, casting coating, screen printing, or the like to form a thin film. Next, in order to induce uniform alignment of the non-photoreactive liquid crystalline substance, the non-photoreactive liquid crystalline substance is heated and maintained near the phase transition temperature for a certain time. By this operation, the orientation of the liquid crystalline polymer is determined in a form in which the molecular orientation in the photoreactive polymer film is transferred. The thickness of the non-photoreactive liquid crystal material layer is from 0.1 μm to 50 μm, and more preferably from 0.5 μm to 5 μm.

As the non-photoreactive liquid crystalline substance used in the present invention, the chemical structure can be freely selected as long as it is a material showing a nematic phase. In particular, polymer liquid crystals and discotic liquid crystals are preferably used. In the case of a polymer liquid crystal, polyacrylate, polymethacrylate, polysiloxane, or the like is used as the polymer main chain.
In addition, as a residue exhibiting liquid crystallinity, a cyanobiphenyl type, a phenylbenzoate type, or the like is suitably used. As the discotic liquid crystal, a triphenylene-based liquid crystal or the like is used. Further, a material in which a dichroic dye is dissolved or dispersed in a liquid crystalline polymer or bonded thereto can be used. This makes it possible to easily manufacture a film in which the dye is oriented.

In the present invention, a protective film can be provided on the alignment film manufactured as described above, if necessary.

The liquid crystal alignment film of the present invention can be used for various optical elements such as a liquid crystal element, a polarizing element and an optical compensation film.

[0027]

The liquid crystal alignment film of the present invention comprises a non-photoreactive liquid crystal on a resin film containing a dichroic photoreactive structural unit, more preferably on a potentially liquid crystal or crystalline resin film. Since the film made of a crystalline material is formed as a self-supporting film, the alignment state of the alignment film made of a liquid crystalline material is stabilized by a high degree of ordering based on liquid crystallinity or crystallinity,
The orientation direction can be arbitrarily controlled. In addition, since linearly polarized light irradiation or non-polarized light irradiation is performed in an oblique direction in the formation of the resin film, photoreactive residues in the film, for example, azobenzene derivatives efficiently absorb light. In addition, since the orientation is performed in an amorphous state,
A small amount of exposure energy is required. Since the liquid crystalline alignment film of the present invention can be formed by coating a non-reactive liquid crystal material layer, it is possible to manufacture an alignment film having a uniform thickness and a large area. Further, the liquid crystalline alignment film of the present invention can be optionally patterned, and a multiaxial alignment film can be produced.

[0028]

Next, the present invention will be described in more detail by way of examples.

Example 1 1-Hydroxy-4-cyanoazobenzene was reacted with methacrylic acid chloride in the presence of triethylamine to obtain 1-methacryloyloxy-4'-cyanoazobenzene. This monomer is polymerized in tetrahydrofuran using azobisisobutyronitrile as a polymerization initiator,
Poly (1-methacryloyloxy-4-cyanoazobenzene) having a weight average molecular weight of 3.8 × 10 ⁴ ((1) in Table 4) was obtained. As a result of a thermal analysis, the melting point of this homopolymer was 240 ° C. This homopolymer was dissolved in cyclohexanone, and the solution was spin-coated on a glass plate to form a thin film. When this thin film was heated to 180 ° C. and then observed at room temperature with a polarizing microscope, it was confirmed that birefringence due to crystallization was developed. Next, a polymer film having a thickness of 50 nm obtained by spin-coating a glass
It was irradiated with polarized light of 36 nm at an irradiation amount of 100 mJ / cm ² and then heated at 240 ° C. for 2 minutes. Next, a liquid crystalline polymer, poly {4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester) (molecular weight: 4200, nematic / isotropic phase transition temperature: 76 ° C.) is formed on the polymer film. ) Of a 20% by weight toluene solution
After spin coating at 20 rpm for 20 seconds, this was applied at 75.5 ° C. for 3 seconds.
Hold for 0 minutes. When this was returned to room temperature and observed with a polarizing microscope, it was found that it was oriented in a monodomain. Uniform orientation was also confirmed by birefringence measurement.

COMPARATIVE EXAMPLE 1 In the same manner as in Example 1, a thin film of poly (1-methacryloyloxy-4-cyanoazobenzene) was 436 nm thick.
After irradiating the linearly polarized light at an irradiation amount of 100 mJ / cm ² ,
Immediately without heat treatment, the same toluene solution of the liquid crystalline polymer was spin-coated and kept at 75.5 ° C. for 30 minutes.
When this was returned to room temperature and observed with a polarizing microscope, the orientation was random.

Example 2 Poly (1-methacryloyloxy-4) used in Example 1
-Cyanoazobenzene) polymer film (film thickness: 50 nm)
The substrate was irradiated with light from a 500 W ultra-high pressure mercury lamp at an incident angle of 60 ° for 1 minute from the substrate surface without passing through a filter. Next, similarly to Example 1, after heating at 240 ° C. for 2 minutes, a toluene solution of poly {4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester) was spin-coated. This was kept at 75.5 ° C. for 30 minutes, then returned to room temperature, and observed with a polarizing microscope, it was found that it was oriented in a monodomain.

Example 3 The 1-methacryloyloxy-4'-cyanoazobenzene obtained in Example 1 and acrylonitrile are radically copolymerized in tetrahydrofuran to obtain a molecular weight having a copolymerization ratio of 1: 0.6. 8 × 10 ⁴ polymers were obtained. A cyclohexanone solution of this polymer was spin-coated on a glass plate to prepare a thin film (thickness: 65 nm), and irradiated with polarized light of 436 nm and an irradiation amount of 100 mJ / cm in the same manner as in Example 1.
^After irradiating at ² , heating at 240 ° C. for 2 minutes. On this thin film, a toluene solution of poly (4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester) was spin-coated at 1000 rpm for 20 seconds. This was kept at 75.5 ° C. for 30 minutes and returned to room temperature, and then observed with a polarizing microscope. As a result, it was found that it was oriented in a monodomain.

Example 4 In the same manner as in Example 1, a thin film of poly (1-methacryloyloxy-4-cyanoazobenzene) was provided on a glass substrate, and the entire surface was irradiated with 436 nm polarized light at an irradiation dose of 500 mJ /.
Irradiated in cm ² . Next, a photomask was placed on the film, and then a 436-nm polarized light with a changed polarization axis of 45 ° was irradiated at a dose of 100 mJ / cm ² . 240
After heating at 2 ° C. for 2 minutes, a toluene solution of poly (4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester) was spin-coated, and the mixture was heated at 75.5 ° C. for 30 minutes.
Hold for minutes. When the temperature was returned to room temperature and observed with a polarizing microscope, a pattern faithful to the photomask was observed and a 2 mm line was resolved.

Example 5 Dioxane of polymethacrylic polymer liquid crystal having a p-cyanoazobenzene and p-cyanobiphenyl group in the side chain (liquid crystal phase / isotropic phase transition temperature = 128 °) ((3) in Table 3) The solution was spin-coated on a glass plate to obtain a thin film. This was irradiated with light from an ultra-high pressure mercury lamp at an incident angle of 60 ° for 1 minute, and then heated at 80 ° C for 10 minutes. This film has a poly-4-
1000 mL of a toluene solution of (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester)
Spin coating at 20 pm for 20 seconds. This was kept at 75.5 ° C. for 30 minutes and returned to room temperature, and then observed with a polarizing microscope. As a result, it was found that it was oriented in a monodomain.

Example 6 In the same manner as in Example 1, 436 nm polarized light was irradiated at a dose of 10
Irradiation at 0 mJ / cm ² was followed by heating at 240 ° C. for 2 minutes. On this thin film, a toluene solution of poly (4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester) in which 5% by weight of a dichroic dye was dissolved was spin-coated at 1000 rpm for 20 seconds. This is 75.5
After maintaining at 30 ° C. for 30 minutes and returning to room temperature, observation via a polarizing sheet confirmed that the dye was uniaxially oriented.

Example 7 Poly {2- [4- (4-methoxyphenylazo) phenyloxy] ethyl methacrylate} (weight average molecular weight =
2.26 × 10 ⁵ , liquid crystal phase / isotropic phase transition temperature = 171
° C) by radical polymerization of the corresponding monomers in toluene. A dioxane solution of this polymer was prepared, and this was spin-coated on a glass substrate to form a film having a thickness of 50%.
nm. When this was irradiated with 436 nm linearly polarized light and then heated to 110 ° C., the dichroism was 0.44.
And increased. On this film, the toluene solution of the polymer liquid crystal used in Example 1 was spin-coated and kept at 75.5 ° C., and as a result, it was confirmed by a polarizing microscope that the polymer liquid crystal film was uniaxially oriented. confirmed.

Example 8 Poly {2- [4- (4-methoxyphenylazo) phenyloxy] hexyl methacrylate} (weight average molecular weight = 1.25 × 10 ⁵ , smectic-nematic phase transition temperature = 95 ° C., nematic・ Isotropic phase transition temperature = 137
° C) by radical polymerization of the corresponding monomers in toluene. A dioxane solution of this polymer was prepared and spin-coated on a glass substrate to form a film having a thickness of 55.
nm. When this was irradiated with linearly polarized light of 436 nm and heated to 110 ° C., the dichroism was 0.64.
Reached. On this film, the toluene solution of the polymer liquid crystal used in Example 1 was spin-coated and kept at 75.5 ° C., and as a result, it was confirmed by a polarizing microscope that the polymer liquid crystal film was uniaxially oriented. confirmed.

Example 9 Poly [2- [4- (4-methoxyphenylazo) phenyloxy] hexyl methacrylate used in Example 8]
Of dioxane was spin-coated on a glass substrate to form a thin film having a thickness of 55 nm. This was irradiated with non-polarized light of 436 nm from the direction of 60 ° from the substrate surface. When the irradiated film was heated to 110 ° C. for 10 minutes, the dichroism reached 0.1. On this film, the toluene solution of the polymer liquid crystal used in Example 1 was spin-coated and kept at 75.5 ° C., and as a result, it was confirmed by a polarizing microscope that the polymer liquid crystal film was uniaxially oriented. confirmed.

Example 10 Poly {2- [4- (4-methoxyphenylazo) phenyloxy] hexyl methacrylate used in Example 8]
Of dioxane was spin-coated on a glass substrate to form a thin film having a thickness of 55 nm. This was irradiated with non-polarized light of 436 nm from the direction of 80 ° from the substrate surface. After placing a photomask on this film, the incident surface for the first irradiation was changed to 9
After being rotated by 0 degrees, irradiation was performed from the substrate surface in the direction of 80 °. This is heated at 110 ° C. for 10 minutes, and on this film,
The toluene solution of the polymer liquid crystal used in Example 1 was spin-coated and maintained at 75.5 ° C. Observation with a polarizing microscope confirmed that a clear image due to birefringence was formed in the polymer liquid crystal film.

Example 11 Poly (1-methacryloyloxy-4) used in Example 1
-Cyanoazobenzene) in a cyclohexanone solution was spin-coated to form a 60 nm thin film on a glass substrate. After irradiating this with linearly polarized light of 436 nm,
Heat at 0 ° C. for 10 minutes. Hexa (4)
-Octyloxybenzoyloxy) triphenylene (discotic nematic / isotropic phase transition temperature = 24)
(4 ° C.) a 10% by weight butanone solution was spin-coated to form a liquid crystal layer, which was heated to 200 ° C., and it was confirmed by polarization microscope observation that the liquid crystal layer was uniaxially oriented.

Example 12 0.5% by weight of azobisisobutyronitrile was added as a polymerization initiator to a 10% by weight benzene solution of methyl p-methacryloyloxycinnamate, and the mixture was degassed at 60-65 ° C. For 6 hours. This was reprecipitated in methanol to isolate poly (methyl p-methacryloyloxycinnamate). Mw = 3.6 × 10 ⁴ , Mw / Mn = 2.1, and Tg = 82 °. This was dissolved in a 1: 1 mixed solvent of dichloromethane and chlorobenzene, and a thin film having a thickness of about 100 nm was formed on a glass substrate by spin coating. 313n wavelength extracted from the ultra high pressure mercury lamp
m of linearly polarized light was applied at a dose of ³ J / cm ² . On this thin film, a toluene solution of 20% by weight of poly {4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester}, which is a liquid crystalline polymer used in Example 1, was rotated at 1000 rpm for 20 seconds. Applied. This was kept at 75.5 ° C. for 30 minutes and then returned to room temperature. Observation with a polarizing microscope revealed that the particles were oriented in a monodomain.

Example 13 0.5% by weight of azobisisobutyronitrile was added as a polymerization initiator to a 10% by weight solution of 7-methacryloyloxycoumarin in benzene, and the resulting mixture was degassed at 60 to 65 ° C. for 6 hours.
Polymerized for hours. This was reprecipitated in methanol to obtain poly (7-methacryloyloxycoumarin). Mw =
3.3 × 10 ⁴ , Mw / Mn = 3.5, Tm = 2
It was 00 $. This was dissolved in DMF, and a thin film having a thickness of about 70 nm was formed on a glass substrate by spin coating. 313nm wavelength extracted from ultra high pressure mercury lamp
At a dose of 8 J / cm ² . On this thin film, a toluene solution of 20% by weight of poly {4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester}, which is a liquid crystalline polymer used in Example 1, was rotated at 1000 rpm for 20 seconds. Applied. This was kept at 75.5 ° C. for 30 minutes and then returned to room temperature. Observation with a polarizing microscope revealed that the particles were oriented in a monodomain.

Example 14 (4-Methacryloyloxyphenylethynyl) benzene was obtained from 4-phenylethynylphenol synthesized from p-bromophenyl acetate and phenylacetylene by methacrylic acid chloride. Azobisisobutyronitrile was used as a polymerization initiator, and a 10% by weight toluene solution of this monomer was subjected to a polymerization reaction. w = 1.43 ×
10 ⁵ , Mw / Mn = 3.2, Tg = 142 ° C. This toluene solution of the polymer was spin-coated on a glass substrate to form a thin film having a thickness of about 70 nm on the glass substrate. 313n wavelength extracted from the ultra high pressure mercury lamp
m of linearly polarized light was applied at a dose of 8 J / cm ² . A 20% by weight toluene solution of poly (4- (3-acryloyloxypropoxy) benzoic acid 4-methoxyphenyl ester) as a liquid crystalline polymer was applied on this thin film in the same manner as in Example 13 at 1000 rpm for 20 seconds. Spin-coated.
This was kept at 75.5 ° C. for 30 minutes and then returned to room temperature. Observation with a polarizing microscope revealed that the particles were oriented in a monodomain.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-168020 (JP, A) JP-A-10-289838 (JP, A) JP-B-7-92567 (JP, B2) Patent 2692033 (JP, A B2) WO 96/37807 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 5/30 B29D 11/00 G02F 1/1335 510

Claims (6)

(57) [Claims] 1. A resin film having a dichroic photoreactive structural unit in a side chain, which is irradiated with linearly polarized light or non-polarized light in an oblique direction, and then a discotic liquid crystal Solution of non-photoreactive liquid crystalline material composed of molecular liquid crystal
A liquid crystalline alignment film characterized by forming a non-photoreactive liquid crystalline material layer by applying a liquid crystal. 2. A potentially liquid crystalline or crystalline resin film having a dichroic photoreactive structural unit in a side chain is irradiated with linearly polarized light or non-polarized light from an oblique direction. Composed of discotic liquid crystal or polymer liquid crystal
A liquid crystal alignment film comprising a non-photoreactive liquid crystal substance layer formed by applying a solution of a non-photoreactive liquid crystal substance. 3. The liquid crystal alignment film according to claim 1, wherein the resin film has been subjected to irradiation of linearly polarized light or irradiation of non-polarized light from an oblique direction and heat treatment. 4. The composition according to claim 1, wherein the dichroic photoreactive structural unit is a potentially liquid crystalline or crystalline structural unit substituted with an azobenzene derivative represented by the following general formula (1). The liquid crystal alignment film according to any one of the above. Embedded image (Where X is a divalent residue bonded to the polymer main chain, Y is a hydrogen atom, an alkyl group having up to 8 carbon atoms, a cycloalkyl group, a cyano group, a nitro group, an alkoxy group having up to 6 carbon atoms, Represents an alkoxycarbonyl group, a halogen group, a trifluoromethyl group or a trifluoromethoxy group having up to 6 carbon atoms) 5. An optical element comprising the liquid crystal alignment film according to claim 1. 6. A potentially liquid crystalline or crystalline resin film having a dichroic photoreactive structural unit in a side chain is irradiated with linearly polarized light or non-polarized light from an oblique direction. rear,
Heat-treated, and further, on the resin film, a non-photo-reactive liquid crystal composed of discotic liquid crystal or polymer liquid crystal
A method for producing a liquid crystalline alignment film, comprising forming a non-photoreactive liquid crystalline material layer by applying a solution of a substance.