JP2002090539A - Optical phase difference film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical phase difference film arbitrarily giving rise to optical phase difference and an optic axis direction inside a polymer material by making linearly polarized ultraviolet rays irradiate a photosensitive compound film from front and rear film surfaces and orienting molecules in the film and a method for manufacturing the same. SOLUTION: The photosensitive compound is film formed. The linearly polarized ultraviolet rays are made to irradiate the film on the front and rear surfaces by using a device consisting of an ultraviolet ray lamp, a power source and an optical element to convert natural light into polarized light (e.g. Glan- Taylor prism). Thereby the photosensitive compound molecules are efficiently oriented in a direction parallel to a field vibration direction of the irradiating linearly polarized ultraviolet rays and vertical to an advancing direction of the irradiating rays. The optic axis is oriented with an arbitrary inclination by irradiating the film source in an oblique direction. Consequently the optical film the optic axis of which is set to be in a desired direction and which has comparatively large optical phase difference even when the film is thin is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of irradiating a film of a photosensitive compound with a linearly polarized ultraviolet ray (hereinafter referred to as "polarization exposure") to orient the molecule to arbitrarily express a phase difference and an optical axis direction. And a method for producing the same. (Particularly, a retardation film in which the optical axis is inclined with respect to the film surface is effective for expanding the viewing angle in a liquid crystal display device.)

[0002]

2. Description of the Related Art A retardation film is a film having a birefringence that allows a linearly polarized light component oscillating in the direction of a main axis perpendicular to each other to pass therethrough and gives a necessary phase difference between the two components.
Such a retardation film has been used in the field of liquid crystal display. In particular, a retardation film having an inclined optical axis is useful as an optical compensation film for expanding the viewing angle of a liquid crystal display device.
There are several conventional techniques for producing such retardation films. One method is to stretch a polymer material such as polycarbonate, orient the polymer chains, and cause a difference between the refractive index in the stretching direction and the refractive index in the direction perpendicular to the stretching direction. Is that, because of the stretching step, molecules are oriented in the stretching direction, so that it is practically impossible to tilt the optical axis. In view of the above problems, a method of arranging a liquid crystalline compound on a stretched film or a substrate that has been subjected to alignment treatment by rubbing or light irradiation has been proposed or put into practical use as a method for producing a retardation film having an inclined optical axis. For example, JP-A-7-287119 and JP-A-7-287120 describe a method of arranging discotic liquid crystals on a rubbing alignment film or a SiO oblique deposition alignment film. As a similar method, Japanese Patent Application Laid-Open No. 10-278123 describes a method in which a discotic liquid crystal containing a photopolymerization initiator is aligned on a photo-alignment film, and the alignment is fixed by light irradiation. The method using an alignment film as described above has problems such as complicating steps such as alignment treatment of the alignment film and alignment of the liquid crystal material.
Furthermore, as another method of manufacturing a retardation film having an inclined optical axis, a method of obliquely vapor-depositing an inorganic dielectric has been proposed, but in order to form a vapor-deposited film continuously on a long sheet. However, there are problems such as an increase in the size of the apparatus and a complicated process. The present inventor has also disclosed in Japanese Patent Laid-Open No.
No. 23 proposes a method for producing a retardation film having a tilted optical axis by polarizing exposure of a side chain type liquid crystalline polymer having photosensitivity. In this case, there is a problem that haze increases.

[0003]

The retardation of a retardation film produced by stretching and orientation of a polymer film is due to the stretching process, and the molecules are oriented in the stretching direction, so that it is extremely difficult to tilt the optical axis. It is. On the other hand, a method of arranging a liquid crystalline compound on an alignment-treated substrate or a method of obliquely depositing an inorganic dielectric can produce a retardation film with an inclined optical axis, but the process is complicated. Therefore, there is a problem that it is not possible to obtain a large-area retardation film having a large-area optical axis inclined at low cost. The present invention provides a method for producing a retardation film with reduced haze and suitable for mass production with simple steps.

[0004]

According to the present invention, there is provided a retardation film in which a birefringence is efficiently developed and an optical axis direction is arbitrarily developed by subjecting a photosensitive compound film to polarized light exposure from the front and back surfaces. In the method for producing a retardation film of the present invention (the retardation film is produced), a photosensitive compound (side chain type liquid crystalline polymer or liquid crystalline compound or a mixture thereof) is formed, and from the front and back surfaces of the film. By performing the polarization exposure, the molecules in the film can be efficiently oriented in a direction parallel to the electric field oscillation direction of the linearly polarized ultraviolet light irradiated and perpendicular to the traveling direction of the irradiation light. By performing this irradiation in an oblique direction with respect to the film surface, the optical axis can be arbitrarily inclined and oriented. As a result, a retardation film in which the optical axis is set in a desired direction can be provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a retardation film of the present invention, a photosensitive compound is formed into a film, the film is polarized and exposed from the front and back surfaces of the film, and if necessary, heated to promote molecular orientation. This is performed by expressing a phase difference. The photosensitive compound may be formed into a film on a support, and may be subjected to polarized light exposure through the support. In this case, the support has a transmittance of light having a wavelength to which the photosensitive compound can react. As long as any material can be used. The higher the transmittance in this case, the smaller the amount of polarized light exposure, which is advantageous in the manufacturing process. Also,
Form a photosensitive compound on a peelable support, and after peeling,
Polarized light exposure can be performed from the front and back surfaces of the film. Furthermore, a photosensitive compound may be formed on a peelable support, the photosensitive compound surface may be subjected to polarized light exposure, and after transferring to the adhesive-treated support, the peeled surface may be exposed.

In the present invention, a retardation film is produced by exposing a photosensitive compound to polarized light. Examples of the photosensitive compound include a liquid crystal polymer having a photosensitive group, a low-molecular liquid crystal compound, and a mixture of these and a low-molecular liquid crystal compound (however, the compounds are not limited thereto. Absent). Further, a small molecule that does not impair the liquid crystallinity is added (for example, an alignment aid for improving the alignment property or a cross-linking agent for improving the heat resistance), or the liquid crystallinity is not impaired. May be copolymerized. Compounds that exhibit a phase difference by such polarized light exposure include substituents such as biphenyl, terphenyl, phenylbenzoate, and azobenzene, which are frequently used as a mesogen component of a liquid crystalline polymer, and cinnamoyl, chalcone, and cinnamylidene groups. , Β- (2
-Furyl) has a side chain containing a structure to which a photosensitive group such as an acryloyl (or a derivative thereof) is bonded, and contains a hydrocarbon, acrylate, methacrylate, maleimide, N
-A liquid crystalline polymer having a structure such as phenylmaleimide or siloxane in the main chain, or a material obtained by mixing the polymer with a liquid crystalline compound.

The details of the present invention will be described by way of examples. Form a film of the material. The film is isotropic at the time of formation, and the side chain portion (and the liquid crystal compound) of the photosensitive liquid crystal polymer is not oriented in a specific direction. This state will be described with reference to FIG.
In 2), a side chain (2) having a photosensitive group represented by a long ellipse
a) [and the liquid crystalline compound (2c) represented by a column] are present (coexist) randomly. When the film is subjected to polarized light exposure on the front and back surfaces (L, L ′: the electric field vibration surface matches the paper surface),
As shown in FIG. 3, a high photosensitivity in the direction corresponding to the electric field oscillation direction of irradiation linearly polarized light and the direction perpendicular to the irradiation light traveling direction near the film surface (P) and the back surface (Q) of the film (33). The photoreaction of the side chain (3a) in the configuration proceeds preferentially. In order to promote this photoreaction, it is necessary to irradiate linearly polarized light having a wavelength at which the photosensitive group can react. This wavelength varies depending on the type of photosensitive group, but is generally 200-
It is 500 nm, and 250-400 nm is particularly effective in many cases. The side chains (3b) [and the liquid crystal compound (3c)], which did not cause a photoreaction because they are not in the direction corresponding to the direction of the electric field of linearly polarized light and the direction perpendicular to the traveling direction of irradiation light, have molecular motion after polarized light exposure. As a result, as shown in FIG.
Orientation in the same direction as the side chain (4a) photoreacted near the front surface (P ') and the back surface (Q') of 4). As a result, in the entire film, the side chains (4b) [and the liquid crystal compound molecules (4c)] of the side chain type liquid crystalline polymer are oriented in the direction of the electric field oscillation of the irradiated linearly polarized light and the direction perpendicular to the direction of the irradiation light. A phase difference is induced. In order to efficiently induce this phase difference, it is also effective to include a side chain having no photosensitive group and to reduce the density of photoreaction points to improve the degree of freedom of molecular motion during reorientation. . The double-sided irradiation, which is a feature of the present invention, effectively promotes the molecular orientation in the film.
This is because anisotropic portions (p, q) are generated near the film surface and near the substrate interface by polarized light exposure, and side chains [and liquid crystal compound molecules] sandwich the disordered portions between the anisotropic portions. The alignment regulating force (due to intermolecular interaction, etc.) due to the liquid crystallinity of the chains [and the liquid crystal compound molecules] extends to the inside of the film, and as a result, the side chains [and the liquid crystal compound molecules]
This is because the orientation of the entire film extends. On the other hand, in the irradiation from one side, as shown in FIG. 5, the anisotropic light reaction on the non-irradiation surface [Q ″: the surface opposite to the irradiation surface (P ″)] of the film (55) sufficiently proceeds. In the vicinity of the non-irradiated surface (Q ''), the side chains (5b) [and the liquid crystal compound molecules (5c)] of the side chain type liquid crystalline polymer remain disordered. The alignment controlling force due to the anisotropy generated on the irradiated surface of the film does not reach near the non-irradiated surface (Q ″), and the alignment of the side chains [and the liquid crystal compound molecules] of the film becomes insufficient. For this reason, the side chain (and the liquid crystal compound molecule) which is originally liquid crystal,
A minute crystal region is randomly formed, and the crystal region scatters light, which causes clouding of the film. Further, since the orientation is insufficient, a retardation cannot be effectively exhibited. When a liquid crystal compound is mixed, the liquid crystal compound may or may not have reactivity, and when it has reactivity, the orientation is firmly fixed, so that the heat resistance is improved. Can be expected. In such a case, it is necessary to control the density of photoreaction points by suppressing the amount of polarized light exposure or adjusting the reactivity so as not to hinder the molecular motion during reorientation. Another method for improving heat resistance is to add a crosslinking agent such as a bifunctional compound. In this case, it is necessary to adjust the amount of addition so as not to hinder molecular orientation. In the method for producing a retardation film of the present invention, the inclination angle of the side chain (and the liquid crystal compound molecule) is gradually changed by changing the incident angle of the irradiation light on both irradiation surfaces of the film or changing the electric field oscillation direction of the irradiation light. It is also possible to perform a hybrid orientation in which the orientation is changed or a twist orientation in which the orientation direction is twisted around an axis perpendicular to the film surface.

A method for synthesizing the starting compound of the photosensitive side-chain type liquid crystalline polymer used in the examples of the present invention will be described below. (Monomer 1) 4,4′-biphenyldiol and 2-chloroethanol were heated under alkaline conditions to synthesize 4-hydroxy-4′-hydroxyethoxybiphenyl. This product is added under alkaline conditions with 1,
6-Dibromohexane was reacted to synthesize 4- (6-bromohexyloxy) -4′-hydroxyethoxybiphenyl. Next, lithium methacrylate was reacted to synthesize 4-hydroxyethoxy-4 ′-(6-methacryloylhexyloxy) biphenyl. Finally,
Under basic conditions, cinnamoyl chloride was added to synthesize a methacrylic ester represented by Chemical Formula 1.

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(Monomer 2) 4-hydroxy-4'-cyanobiphenyl is reacted with 1,6-dibromohexane under alkaline conditions to give 4- (6-bromohexyloxy)-
4′-cyanobiphenyl was synthesized. Next, lithium methacrylate was reacted to synthesize 4-cyano-4 ′-(6-methacryloylhexyloxy) biphenyl represented by Chemical Formula 2.

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(Polymer 1) Polymer 1 was obtained by dissolving this monomer 1 in tetrahydrofuran, adding AIBN (azobisisobutyronitrile) as a reaction initiator and polymerizing. This polymer 1 exhibited liquid crystallinity in a temperature range of 47 to 75 ° C.

(Polymer 2) Polymer 1 is obtained by dissolving Monomer 1 and Monomer 2 in tetrahydrofuran, adding AIBN (azobisisobutyronitrile) as a reaction initiator and polymerizing. (A: b = 55: 45). This polymer 2
Exhibited liquid crystallinity in a temperature range of 44 to 95 ° C.

(Reactive liquid crystal compound 1) Methyl 4-octenyloxybenzoate was synthesized by heating methyl p-hydroxybenzoate and bromooctene under alkaline conditions. The product is heated under alkaline conditions and
-Octenyloxybenzoic acid was synthesized. Next, 4-octenyloxybenzoic acid chloride was synthesized by reacting with thionyl chloride, and reacted with methylhydroquinone to synthesize a reactive liquid crystal compound 1 represented by Chemical Formula 3.

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[0013]

FIG. 1 shows an example of a method (apparatus) for producing an alignment film of the present invention. The disordered light (16, 16 ') generated by the ultraviolet lamp (11, 11') excited by the power supply (12, 12 ') is applied to the optical element (13, 1').
3 ') A base material (15) which is converted into linearly polarized ultraviolet rays (17, 17') by a (for example, a Glan-Taylor prism) and has a light-transmitting wavelength at which a photosensitive compound can react. The photosensitive compound (14) applied (coated) thereon is irradiated. Examples 1 to 5 are examples in which a retardation film having an inclined optical axis was produced by the production method of the present invention. Comparative Examples 1 to 5 are comparative examples in which a photosensitive compound having the same configuration as in Examples 1 to 5 was used to produce a retardation film by irradiation from the coating film surface (one side). The results are shown in Table 1.

[Table 1]

Example 1 3.75% by weight of polymer 1 and 1.25% by weight of liquid crystal material E7 (Merck Japan)
Was dissolved in dichloroethane and applied on a quartz substrate to a thickness of about 3 μm. The substrate was tilted at 45 degrees with respect to the horizontal plane, the coated surface was arranged as an irradiation surface, and ultraviolet light converted to linearly polarized light using a Glan-Taylor prism was irradiated at 120 mJ / cm ² at room temperature from a direction perpendicular to the horizontal plane. Subsequently, the substrate is turned upside down and the ultraviolet light converted to linearly
Irradiation was performed at 20 mJ / cm ² . Next, after heating to 100 ° C., it was cooled to room temperature. The substrate thus obtained had an optical axis inclined by 20 ° from the normal direction of the substrate, had a phase difference of 148.7 nm in the substrate plane, had almost no haze, and was sufficiently practical. .

Example 2 3.75% by weight of polymer 1 and 1.25% by weight of liquid crystal material E7 (Merck Japan)
Was dissolved in dichloroethane and applied on a quartz substrate to a thickness of about 3 μm. The substrate was tilted at 45 degrees with respect to the horizontal plane, the coated surface was arranged as an irradiation surface, and ultraviolet light converted to linearly polarized light using a Glan-Taylor prism was irradiated at 120 mJ / cm ² at room temperature from a direction perpendicular to the horizontal plane. Subsequently, the substrate is turned upside down and the ultraviolet light converted to linearly
Irradiation was performed at 20 mJ / cm ² . Next, after heating to 100 ° C., it was cooled to room temperature. In the substrate thus obtained, the optical axis was inclined by 13 ° from the normal direction of the substrate, and the in-plane phase difference of the substrate was 161.1 nm.

Example 3 5% by weight of polymer 2 was dissolved in dichloroethane and applied on a quartz substrate to a thickness of about 3 μm. The substrate was tilted at 45 degrees with respect to the horizontal plane, the coating surface was arranged so as to be the irradiation surface, and ultraviolet light converted to linearly polarized light using a Glan-Taylor prism was irradiated at 90 mJ / cm ² at room temperature from a direction perpendicular to the horizontal plane. Then, the ultraviolet light obtained by converting the substrate to linearly polarized light by turning the substrate upside down was 90 mJ / c.
m ² irradiation. Next, after heating to 100 ° C., it was cooled to room temperature. In the substrate thus obtained, the optical axis is inclined by 23 ° from the normal direction of the substrate, and the phase difference in the substrate plane is 72.
It was 2 nm.

Example 4 3.75% by weight of Polymer 1 and 1.25% by weight of Reactive Liquid Crystal Compound 1 were dissolved in dichloroethane and applied on a quartz substrate to a thickness of about 3 μm. The substrate was tilted at 45 ° with respect to the horizontal plane, the coated surface was arranged as an irradiation surface, and ultraviolet light converted to linearly polarized light using a Glan-Taylor prism was irradiated at room temperature from the direction perpendicular to the horizontal plane at 60 mJ / cm ^2. Subsequently, the substrate was turned upside down and the ultraviolet light converted to linearly polarized light was turned to 60 mJ / cm.
^Two irradiations were performed. Next, after heating to 100 ° C., it was cooled to room temperature. Furthermore, unpolarized ultraviolet light is applied at room temperature to 1 J / cm ^2.
Irradiated. In the substrate thus obtained, the optical axis is inclined by 18 ° from the normal direction of the substrate, and the phase difference in the substrate plane is 83.
It was 3 nm.

Example 5 2.5% by weight of polymer 1,
2.5% by weight of liquid crystal material E7 (Merck Japan) and 0.0375% by weight of difunctional monomer HX-620
(Nippon Kayaku) was dissolved in dichloroethane and applied on a quartz substrate to a thickness of about 3 μm. Place the substrate 4
The ultraviolet light, which was tilted by 5 degrees and arranged so that the application surface became the irradiation surface, and was converted to linearly polarized light by using a Glan-Taylor prism, was irradiated at room temperature from a direction perpendicular to the horizontal plane at room temperature by 60 mJ / cm ^2.
Then, the substrate was turned upside down and irradiated with UV light of 60 mJ / cm ² similarly converted to linearly polarized light. Next, at 100 ° C
And then cooled to room temperature. Further, the substrate was irradiated with unpolarized ultraviolet light at 1 J / cm ² at room temperature. The substrate thus obtained has an optical axis inclined by 18 ° from the normal direction of the substrate,
The in-plane retardation of the substrate was 103.6 nm.

Comparative Example 1 3.75% by weight of polymer 1 and 1.25% by weight of liquid crystal material E7 (Merck Japan)
Was dissolved in dichloroethane and applied on a glass substrate to a thickness of about 3 μm. Tilt the substrate 45 degrees with respect to the horizontal plane,
The coated surface was arranged as an irradiation surface, and ultraviolet light converted into linearly polarized light using a Glan-Taylor prism was irradiated at 120 mJ / cm ² from a direction perpendicular to a horizontal plane at room temperature.
Next, after heating to 100 ° C., it was cooled to room temperature. In the substrate thus obtained, the optical axis is tilted by 22 ° from the normal direction of the substrate, the phase difference in the substrate plane is 76.5 nm,
There was almost no haze, and the film was sufficiently usable for practical use.

Comparative Example 2 3.75% by weight of polymer 1 and 1.25% by weight of liquid crystal material E7 (Merck Japan)
Was dissolved in dichloroethane and applied on a glass substrate to a thickness of about 3 μm. Tilt the substrate 30 degrees with respect to the horizontal plane,
The coated surface was arranged as an irradiation surface, and ultraviolet light converted into linearly polarized light using a Glan-Taylor prism was irradiated at 120 mJ / cm ² from a direction perpendicular to a horizontal plane at room temperature.
Next, after heating to 100 ° C., it was cooled to room temperature. In the substrate thus obtained, the optical axis was inclined by 15 ° from the normal direction of the substrate, and the in-plane phase difference of the substrate was 82.6 nm.

Comparative Example 3 Polymer 2 was dissolved in dichloroethane and applied on a glass substrate to a thickness of about 3 μm. The substrate was tilted at 45 degrees with respect to the horizontal plane, the coating surface was arranged so as to be the irradiation surface, and ultraviolet light converted to linearly polarized light using a Glan-Taylor prism was irradiated at 90 mJ / cm ² at room temperature from a direction perpendicular to the horizontal plane. did. Next, after heating to 100 ° C., it was cooled to room temperature. The optical axis of the substrate thus obtained was inclined by 23 ° from the normal direction of the substrate, and the in-plane phase difference of the substrate was 48.6 nm.

Comparative Example 4 3.75% by weight of Polymer 1 and 1.25% by weight of Reactive Liquid Crystal Compound 1 were dissolved in dichloroethane and applied on a glass substrate to a thickness of about 3 μm. The substrate was tilted at 45 ° with respect to the horizontal plane, the coated surface was arranged as an irradiation surface, and ultraviolet light converted to linearly polarized light using a Glan-Taylor prism was irradiated at room temperature from the direction perpendicular to the horizontal plane at 60 mJ / cm ^2. did. Next, at 100 ° C
And then cooled to room temperature. Further, the substrate was irradiated with unpolarized ultraviolet light at 1 J / cm ² at room temperature. The substrate thus obtained has an optical axis inclined by 21 ° from the normal direction of the substrate,
The in-plane retardation of the substrate was 38.0 nm.

Comparative Example 5 2.5% by weight of polymer 1,
2.5% by weight of liquid crystal material E7 (Merck Japan) and 0.0375% by weight of difunctional monomer HX-620
(Nippon Kayaku) was dissolved in dichloroethane and applied on a glass substrate to a thickness of about 3 μm. The substrate was tilted at 45 degrees with respect to the horizontal plane, the coated surface was arranged so as to be an irradiation surface, and ultraviolet light converted to linearly polarized light using a Glan-Taylor prism was applied at room temperature from a direction perpendicular to the horizontal plane at 60 mJ / cm ^2.
Irradiated. Next, after heating to 100 ° C., it was cooled to room temperature. Further, the substrate was irradiated with unpolarized ultraviolet light at 1 J / cm ² at room temperature. In the substrate thus obtained, the optical axis is inclined by 20 ° from the normal direction of the substrate, and the phase difference in the substrate plane is 55.0.
nm.

The results of Examples 1 to 5 and Comparative Examples 1 to 5 are summarized in Table 1. From these examples, it has been proved that the phase difference can be effectively obtained by the polarized light exposure from the front and back surfaces of the film, and that a film whose optical axis direction is controlled can be produced. In the birefringent film of the present invention and the method for producing the same, the film that has caused birefringence by polarized light exposure is further irradiated with ultraviolet light to promote the photoreaction of unreacted photosensitive groups, thereby firmly orienting the orientation in the film. Can be fixed. Such a birefringent film was excellent in heat resistance and light stability and was sufficient for practical use.

[0025]

According to the present invention, a photosensitive compound is formed into a film, and a simple operation of irradiating linearly polarized light from the front and back surfaces of the film is performed.
A retardation can be effectively developed in the film. A retardation film can be obtained without using a conventional technique such as a stretching step. Further, by changing the irradiation direction of linearly polarized ultraviolet rays, it is possible to produce regions having different optical axes within the same substrate. It is expected to be used for various optical elements. Further, the retardation film having an inclined optical axis can be used as an optical compensation film for expanding a viewing angle in a liquid crystal display device using a twisted nematic liquid crystal utilizing an optical rotation mode and a birefringence mode. Conventionally, such a retardation film with an inclined optical axis could not be produced at a low cost in a large area. However, according to the present invention, a large area can be produced by a simple operation of performing polarized light exposure from an oblique direction. It became.

[0026]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a method for producing a retardation film of the present invention.

FIG. 2 is a schematic diagram showing the state of molecules (side chains of a photosensitive liquid crystalline polymer and a liquid crystalline compound) during film formation.

FIG. 3 is a schematic view of a side chain photoreacted by polarized light exposure from the front and back surfaces of the film.

FIG. 4 is a schematic view of a side chain and a liquid crystalline compound arranged by molecular motion after polarized light exposure.

FIG. 5 is a schematic view of a side chain and a liquid crystalline compound arranged by one-sided irradiation.

[Explanation of symbols]

11, 11 ': UV lamp 12, 12': Power supply 13, 13 ': Optical element (Glan-Taylor prism) 14: Photosensitive compound 15: Base material 16, 16' ..Disordered light 17,17 ': linearly polarized ultraviolet light

Claims (9)

[Claims] 1. A retardation film and a method for producing the same, which are produced by a process including an operation of irradiating a photosensitive compound film with light from both directions. 2. A retardation film, comprising: a step of irradiating a light-sensitive compound film formed on a support with light from both directions of a front surface and a back surface via the support. Its manufacturing method. 3. The retardation film according to claim 1, wherein the photosensitive compound has liquid crystallinity, and a method for producing the same. 4. The retardation film according to claim 1, wherein the photosensitive compound is a mixture of a photosensitive polymer and a liquid crystal compound, and a method for producing the same. 5. The retardation film according to claim 1, wherein the photosensitive compound is a mixture of a photosensitive polymer having liquid crystallinity and a liquid crystalline compound, and a method for producing the same. 6. The retardation film according to claim 4, wherein the liquid crystalline compound has reactivity, and a method for producing the same. 7. A retardation film in which the light applied in claim 1, 2, 3, 4, 5, or 6 is linearly or partially polarized, and a method for producing the same. . 8. The retardation film and the method for producing the retardation film according to claim 1, further comprising a step of heating and / or cooling. 9. The retardation film and the method for producing the retardation film according to claim 1, further comprising a step of crosslinking.