WO2023163119A1 - Antireflection film and organic electroluminescent display device - Google Patents

Abstract

The present invention addresses the problem of providing an antireflection film that can suppress the occurrence of iridescent unevenness when used in an organic EL display device, and also providing the organic EL display device. This antireflection film has a polarizer, a first optically anisotropic film, and a second optically anisotropic film in this order. The first optically anisotropic film and the second optically anisotropic film both have an optically anisotropic layer formed by fixing an oriented liquid crystal compound. The first optically anisotropic film and the second optically anisotropic film are laminated with an adhesive layer interposed therebetween, and the standard deviation σ of the film thickness value calculated when the thickness of the adhesive layer is measured with an interferometric film thickness meter is less than 35 nm.

Description

Antireflection film and organic electroluminescent display device

The present invention relates to an antireflection film and an organic electroluminescence display device.

Optically anisotropic layers having refractive index anisotropy are applied to various uses such as antireflection films for organic electroluminescence (EL) displays and optical compensation films for liquid crystal displays.
For example, Patent Document 1 discloses a retardation plate in which two kinds of optically anisotropic layers exhibiting predetermined optical properties are laminated.

Patent No. 5960743

The present inventors have studied a retardation plate having a plurality of optically anisotropic layers described in Patent Document 1 and the like, and found that when the optically anisotropic layers are laminated via an adhesive layer, clarified that in-plane color unevenness (hereinafter abbreviated as "rainbow unevenness") occurs when the film is used as an antireflection film in an organic EL display device.

Therefore, an object of the present invention is to provide an antireflection film and an organic EL display device that can suppress the occurrence of iridescent unevenness when used in an organic EL display device.

As a result of intensive studies by the present inventors in order to achieve the above problems, the use of an antireflection film in which optically anisotropic layers are laminated using a specific pressure-sensitive adhesive layer is effective when used in an organic EL display device. The inventors have found that the occurrence of iridescent unevenness can be suppressed, and have completed the present invention.
That is, the inventors have found that the above problems can be solved by the following configuration.

[1] An antireflection film comprising a polarizer, a first optically anisotropic film, and a second optically anisotropic film in this order,
Both the first optically anisotropic film and the second optically anisotropic film have an optically anisotropic layer formed by fixing an oriented liquid crystal compound,
The first optically anisotropic film and the second optically anisotropic film are laminated via an adhesive layer,
An antireflection film having a standard deviation σ of less than 35 nm of film thickness values calculated when the thickness of the pressure-sensitive adhesive layer is measured by an interference film thickness meter.
[2] An antireflection film comprising a polarizer, a first optically anisotropic film, and a second optically anisotropic film in this order,
Both the first optically anisotropic film and the second optically anisotropic film have an optically anisotropic layer formed by fixing an oriented liquid crystal compound,
The first optically anisotropic film and the second optically anisotropic film are laminated via an adhesive layer,
The ratio of the standard deviation σ (nm) of the film thickness value calculated when the thickness of the adhesive layer is measured with an interference film thickness gauge to the thickness (μm) of the adhesive layer is 7.0 or less. prevention film.
[3] The antireflection film of [1] or [2], wherein the first optically anisotropic film has a refractive index of 1.50 or more and 1.70 or less.
[4] The antireflection film according to any one of [1] to [3], wherein the pressure-sensitive adhesive layer has a refractive index of 1.36 or more and 1.53 or less.
[5] The antireflection film of any one of [1] to [4], wherein the first optically anisotropic film has an in-plane retardation of 140 to 220 nm at a wavelength of 550 nm.
[6] The antireflection film is elongated,
The antireflection film according to any one of [1] to [5], wherein the angle between the longitudinal direction of the antireflection film and the in-plane slow axis of the first optically anisotropic film is 40 to 85°. .
[7] The antireflection film of any one of [1] to [6], wherein the first optically anisotropic film is an optically anisotropic layer formed by fixing a vertically aligned discotic liquid crystal compound.
[8] The antireflection film of any one of [1] to [7], wherein the second optically anisotropic film is composed of two or more optically anisotropic layers.
[9] The second optically anisotropic film comprises an optically anisotropic layer in which a twisted rod-like liquid crystal compound having a helical axis in the thickness direction is fixed, and an optical film in which a vertically aligned rod-like liquid crystal compound is fixed. The antireflection film according to any one of [1] to [8], which is composed of a laminate with an anisotropic layer.
[10] The antireflection film according to any one of [1] to [9], wherein the pressure-sensitive adhesive layer has a thickness of 2 to 20 µm.
[11] An organic electroluminescence display device comprising the antireflection film according to any one of [1] to [10].

According to the present invention, it is possible to provide an antireflection film and an organic EL display device that can suppress the occurrence of iridescent unevenness when used in an organic EL display device.

FIG. 1 is an example of a schematic cross-sectional view of one embodiment of the antireflection film of the present invention. FIG. 2 shows the relationship between the absorption axis of the polarizer and the in-plane slow axes of the first optically anisotropic film and the second optically anisotropic film in one embodiment of the antireflection film of the present invention. FIG. 4 is a diagram showing relationships; FIG. 3 shows the relationship between the absorption axis of the polarizer and the in-plane slow axes of the first optically anisotropic film and the second optically anisotropic film when observed from the direction of the white arrow in FIG. FIG. 4 is a schematic diagram showing the relationship of angles;

The present invention will be described in detail below.
The description of the constituent elements described below may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
In this specification, a numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.
Moreover, in this specification, each component may use the substance applicable to each component individually by 1 type, or may use 2 or more types together. Here, when two or more substances are used in combination for each component, the content of the component refers to the total content of the substances used in combination unless otherwise specified.
Further, in this specification, "(meth)acryl" is a notation representing "acryl" or "methacryl", and "(meth)acryloyl" is a notation representing "acryloyl" or "methacryloyl".
Next, the terms used in this specification will be explained.

In this specification, the slow axis is defined at 550 nm unless otherwise specified.

In this specification, Re(λ) and Rth(λ) represent in-plane retardation and thickness direction retardation at wavelength λ, respectively. Unless otherwise specified, the wavelength λ is 550 nm.
In the present invention, Re(λ) and Rth(λ) are values measured at wavelength λ with AxoScan (manufactured by Axometrics). By entering the average refractive index ((nx+ny+nz)/3) and film thickness (d (μm)) in AxoScan,
Slow axis direction (°)
Re(λ)=R0(λ)
Rth(λ)=((nx+ny)/2−nz)×d
is calculated.
Note that R0(λ), which is displayed as a numerical value calculated by AxoScan, means Re(λ).

In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.) using a sodium lamp (λ=589 nm) as the light source. Further, when measuring the wavelength dependence, it can be measured by using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter.
Also, the values in the polymer handbook (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. Average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

The term "light" used herein means actinic rays or radiation, and includes, for example, the emission line spectrum of mercury lamps, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays (EUV light: Extreme Ultraviolet), X-rays, ultraviolet rays, and electron beam (EB). Among them, ultraviolet rays are preferable.

As used herein, "visible light" refers to light of 380 to 780 nm. In this specification, the measurement wavelength is 550 nm unless otherwise specified.
Further, in this specification, the angular relationship (for example, "perpendicular", "parallel", etc.) shall include the range of error that is permissible in the technical field to which the present invention belongs. Specifically, it means that the exact angle is within a range of less than ±10°, and the error from the strict angle is preferably within a range of ±5° or less, and within a range of ±3° or less. is more preferable.

In the present specification, the horizontal orientation of the rod-like liquid crystal compound refers to a state in which the major axes of the liquid crystal compound are aligned horizontally and in the same direction with respect to the layer surface.
Here, the term "horizontal" does not mean that the layer is strictly horizontal, but means an orientation in which the tilt angle between the average molecular axis of the liquid crystal compound in the layer and the layer surface is less than 20°.
Further, the same orientation does not strictly require the same orientation, but when the slow axis orientation is measured at arbitrary 20 positions in the plane, the slow axis The maximum difference in the slow axis orientations among the orientations of .
The vertical alignment of the discotic liquid crystal compound means a state in which the disc axis of the liquid crystal compound is aligned perpendicularly to the layer surface and in the same direction.
Here, the term "perpendicular" does not mean that the liquid crystal compound in the layer must be strictly perpendicular, but means that the liquid crystal compound in the layer has an inclination angle of 70 to 110° between the disc surface and the layer surface.
Further, the same orientation does not strictly require the same orientation, but when the slow axis orientation is measured at arbitrary 20 positions in the plane, the slow axis The maximum difference in the slow axis orientations among the orientations of .

As used herein, the optically anisotropic layer refers to a layer formed by fixing an aligned liquid crystal compound.
The "fixed" state is a state in which the orientation of the liquid crystal compound is maintained. Specifically, the layer does not have fluidity at a temperature range of 0 to 50° C., or -30 to 70° C. under more severe conditions, and the orientation is changed by an external field or force. It is more preferable to be in a state in which the fixed alignment form can be stably maintained.

[Anti-reflection film]
The antireflection film according to the first embodiment of the present invention is an antireflection film having a polarizer, a first optically anisotropic film, and a second optically anisotropic film in this order.
Further, in the antireflection film according to the first embodiment of the present invention, both the first optically anisotropic film and the second optically anisotropic film are optically anisotropic films in which an oriented liquid crystal compound is fixed. It has an anisotropic layer.
Also, in the antireflection film according to the first embodiment of the present invention, the first optically anisotropic film and the second optically anisotropic film are laminated via an adhesive layer.
In the antireflection film according to the first embodiment of the present invention, the standard deviation σ of the film thickness value calculated when the thickness of the pressure-sensitive adhesive layer is measured with an interference film thickness meter (hereinafter referred to as “thickness unevenness σ” ) is less than 35 nm.

The antireflection film according to the second embodiment of the present invention is an antireflection film having a polarizer, a first optically anisotropic film, and a second optically anisotropic film in this order.
Further, in the antireflection film according to the second embodiment of the present invention, both the first optically anisotropic film and the second optically anisotropic film are optically anisotropic films in which an oriented liquid crystal compound is fixed. It has an anisotropic layer.
Also, in the antireflection film according to the second embodiment of the present invention, the first optically anisotropic film and the second optically anisotropic film are laminated via an adhesive layer.
Further, in the antireflection film according to the second embodiment of the present invention, the thickness (μm) of the pressure-sensitive adhesive layer is calculated when the thickness of the pressure-sensitive adhesive layer is measured with an interference film thickness meter. The ratio of deviation σ (nm) [thickness unevenness σ (nm)/thickness (μm)] is 7.0 or less.
That is, the antireflection film according to the second embodiment of the present invention is the same as the antireflection film according to the first embodiment of the present invention except for the thickness of the adhesive layer.

Here, the pressure-sensitive adhesive layer in the antireflection film according to the first embodiment and the second embodiment of the present invention (hereinafter simply abbreviated as "antireflection film of the present invention" when no distinction is required) The thickness value (unit: μm) and the thickness unevenness σ (unit: nm) refer to values calculated under the following conditions.
The thickness of the adhesive layer is determined by measuring the reflectance of the antireflection film (objective lens: 5x) using a microscopic spectroscopic film thickness meter (OPTM, manufactured by Otsuka Electronics), and Fourier analysis using the analysis software in the same device. Calculated by conversion (calculation wavelength: 400 to 800 nm, Bell function: available). Specifically, from the power spectrum calculated by the Fourier transform under the above conditions, after detecting the peak corresponding to the optical thickness of each of the optically anisotropic layer and the pressure-sensitive adhesive layer, the optical film of the pressure-sensitive adhesive layer The thickness of the adhesive layer is calculated by dividing the thickness by the refractive index of the adhesive layer. This measurement and calculation are performed at intervals of 1 mm for 3 cm from an arbitrary position on the antireflection film, and the average value of the calculation results of 31 points is taken as the "thickness of the pressure-sensitive adhesive layer."
Further, the thickness unevenness σ is calculated as the standard deviation of the thickness of the pressure-sensitive adhesive layer at 31 points obtained by performing the above measurement from an arbitrary position of the antireflection film at intervals of 3 cm and 1 mm.

In the present invention, the thickness unevenness σ of the adhesive layer is less than 35 nm, or the ratio [thickness unevenness σ (nm)/thickness (μm)] is 7.0 or less. It is possible to suppress the occurrence of iridescent unevenness when used in an EL display device.
Although this is not clear in detail, the present inventors presume as follows.
That is, when the antireflection film of the present invention is used, any one of the first optically anisotropic film and the second optically anisotropic film arranged on the viewing side when used in an organic EL display device, Interference light generated at the interface with the pressure-sensitive adhesive layer can be homogenized in the plane, so it is thought that the occurrence of iridescent unevenness could be suppressed.

In the antireflection film according to the first embodiment of the present invention, as described above, the thickness unevenness σ of the pressure-sensitive adhesive layer is less than 35 nm, and the first optically anisotropic film and the second optically anisotropic film The thickness is preferably more than 3 nm because it is difficult for air bubbles to enter during lamination with the film. That is, the thickness unevenness σ of the pressure-sensitive adhesive layer is preferably more than 3 nm and less than 35 nm, more preferably 5 nm or more and 30 nm or less.
In the antireflection film according to the second embodiment of the present invention, the adhesive layer ratio [thickness unevenness σ (nm)/thickness (μm)] is 7.0 or less. Since it can be suppressed, it is preferably 4.5 or less. Although the lower limit is not particularly limited, it is preferably 0.1 or more.

The polarizer, the first optically anisotropic film and the second optically anisotropic film, and the first optically anisotropic film and the second optically anisotropic film of the antireflection film of the present invention are described below. The pressure-sensitive adhesive layer (hereinafter abbreviated as "specific pressure-sensitive adhesive layer") used for lamination with a flexible film will be described in detail, but the specific pressure-sensitive adhesive layer, which is a feature of the present invention, will be described first.

[Specific adhesive layer]
The specific pressure-sensitive adhesive layer of the antireflection film of the present invention has a thickness unevenness σ of less than 35 nm in the first aspect, and a ratio [thickness unevenness σ (nm)/thickness (μm)] in the second aspect. If it is 7.0 or less, a conventionally known pressure-sensitive adhesive layer can be used.

Examples of adhesives contained in the specific adhesive layer include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, and polyvinylpyrrolidone-based adhesives. Examples include pressure-sensitive adhesives, polyacrylamide-based pressure-sensitive adhesives, cellulose-based pressure-sensitive adhesives, and the like.
Among these, acrylic adhesives (pressure-sensitive adhesives) are preferable from the viewpoint of transparency, weather resistance, heat resistance, and the like.
As the acrylic pressure-sensitive adhesive, a (meth)acrylic polymer is used and usually contains alkyl (meth)acrylate as a main component as a monomer unit.
Examples of the alkyl (meth)acrylate constituting the main skeleton of the (meth)acrylic polymer include linear or branched alkyl groups having 1 to 18 carbon atoms. These can be used alone or in combination. The average carbon number of these alkyl groups is preferably 3-9. Alkyl (meth)acrylates containing an aromatic ring such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate can also be used. The alkyl (meth) acrylate containing an aromatic ring may be used by mixing a polymer obtained by polymerizing this with the (meth) acrylic polymer exemplified above, or may be used by copolymerizing with the alkyl (meth) acrylate. good too. From the viewpoint of transparency, copolymerization is preferred.
Details of the adhesive are described, for example, in [0071]-[0084] of JP-A-2018-60014. The description of the publication is incorporated herein by reference.

The method for forming the specific pressure-sensitive adhesive layer is not particularly limited, but for example, a method of applying a pressure-sensitive adhesive solution onto a release sheet, drying it, and then transferring it to the surface of a transparent polymer layer; It can be formed by a method of applying directly to the surface of the polymer layer and drying.
The adhesive solution is prepared as a solution of about 10 to 40% by mass by dissolving or dispersing the adhesive in a solvent such as toluene or ethyl acetate.
As the coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, a spray method, or the like can be employed.
However, from the viewpoint of suppressing chemical cracks in the cycloolefin polymer, it is preferable to dry so that the solvent does not remain.

Materials constituting the release sheet include, for example, synthetic polymer films such as polyethylene, polypropylene, and polyethylene terephthalate; rubber sheets; paper; cloth; mentioned.

In the present invention, the refractive index of the specific pressure-sensitive adhesive layer is preferably 1.36 or more and 1.53 or less. more preferred.

Further, in the present invention, the thickness of the specific pressure-sensitive adhesive layer is preferably 2 to 20 μm, more preferably 3 to 15 μm, more preferably 4 to 12 μm, for the reason of good durability. More preferred.

[Polarizer]
The polarizer included in the antireflection film of the present invention may be any member as long as it has a function of converting natural light into specific linearly polarized light, and examples thereof include absorptive polarizers.
The type of polarizer is not particularly limited, and commonly used polarizers can be used. Examples thereof include iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. Iodine-based polarizers and dye-based polarizers are generally produced by allowing polyvinyl alcohol to adsorb iodine or a dichroic dye and stretching the resultant.
A protective film may be arranged on one side or both sides of the polarizer.

Further, as described in WO 2019/131943 and JP 2017-83843 A, as a polarizer, without using polyvinyl alcohol as a binder, a liquid crystal compound and a dichroic organic dye (e.g., A coated polarizer prepared by coating using a dichroic azo dye used in a light-absorbing anisotropic film described in International Publication No. 2017/195833 may be used. That is, the polarizer may be a polarizer formed using a composition containing a polymerizable liquid crystal compound.
This coated polarizer is a technique for orienting a dichroic organic dye by utilizing the orientation of a liquid crystal compound. As described in JP-A-2012-83734, when the polymerizable liquid crystal compound exhibits smectic properties, it is preferable from the viewpoint of increasing the degree of orientation. Alternatively, as described in International Publication No. 2018/186503, it is preferable to crystallize the dye from the viewpoint of increasing the degree of orientation. WO 2019/131943 describes a structure of polymer liquid crystals that is preferable for increasing the degree of orientation.

A polarizer in which a dichroic organic dye is oriented by utilizing the orientation of liquid crystal without stretching has the following characteristics. It can be made very thin with a thickness of about 0.1 μm to 5 μm, and as described in JP-A-2019-194685, it is difficult for cracks to occur when bent and thermal deformation is small. As described in 1., even a polarizing plate with a high transmittance exceeding 50% has many advantages such as excellent durability.
By taking advantage of these advantages, it can be used for applications requiring high brightness, small size and light weight, applications for fine optical systems, applications for molding parts having curved surfaces, and applications for flexible parts. Of course, it is also possible to peel off the support and transfer the polarizer for use.

Regarding the transmittance of the polarizer, the visibility correction single transmittance is preferably 40% or more, more preferably 44% or more, and even more preferably 50% or more, from the viewpoint of power saving. The upper limit is not particularly limited, and is preferably 60% or less.
In the present invention, the luminous efficiency correction single transmittance of the polarizer is measured using an automatic polarizing film measuring device: VAP-7070 (manufactured by JASCO Corporation). The visibility correction single transmittance can be measured as follows. A sample (5 cm×5 cm) is prepared by pasting a polarizer onto glass via an adhesive. At this time, the polarizing plate protective film is attached to the polarizer so as to face the opposite side (air interface) to the glass. Set the glass side of the sample toward the light source and measure.
The structure of the polarizer protective film is not particularly limited, and may be, for example, a support or a coating layer, or a laminate of a support and a coating layer.
As the coating layer, a known layer can be used, and for example, a layer obtained by polymerizing and curing a polymer or a polyfunctional monomer may be used. Polymers include (meth)acrylic polymers and cycloolefin polymers. Polymerizable monomers include radically polymerizable or cationically polymerizable compounds.
The bonding surface between the polarizer and the protective film is not particularly limited. A side may be laminated with a polarizer.

[First optically anisotropic film]
The first optically anisotropic film of the antireflection film of the present invention has an optically anisotropic layer in which an oriented liquid crystal compound is fixed.
Here, the liquid crystal compound can be classified into a rod-like type and a disk-like type according to its shape. Furthermore, there are low-molecular-weight and high-molecular-weight types, respectively. Polymers generally refer to those having a degree of polymerization of 100 or more (Polymer Physics: Phase Transition Dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992). Although any liquid crystal compound can be used in the present invention, rod-like liquid crystal compounds or discotic liquid crystal compounds (disk-like liquid crystal compounds) are preferred. Further, a monomer or a relatively low-molecular-weight liquid crystal compound having a degree of polymerization of less than 100 is preferable.
Moreover, the liquid crystal compound preferably has a polymerizable group from the viewpoint of fixing the alignment. Such polymerizable groups include, for example, acryloyl groups, methacryloyl groups, epoxy groups, and vinyl groups. In addition, below, the liquid crystal compound which has a polymerizable group is abbreviated as a "polymerizable liquid crystal compound."
By polymerizing such a polymerizable liquid crystal compound, the orientation of the liquid crystal compound can be fixed. After the liquid crystal compound is fixed by polymerization, it is no longer necessary to exhibit liquid crystallinity.

Rod-shaped liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. These rod-like liquid crystal compounds are fixed by introducing a polymerizable group into the terminal structure of the rod-like liquid crystal compound (similar to the disk-like liquid crystal described below) and utilizing this polymerization and curing reaction. As a specific example, an example in which a polymerizable nematic rod-like liquid crystal compound is cured with ultraviolet light is described in JP-A-2006-209073. Moreover, not only the low-molecular-weight liquid crystal compounds described above, but also high-molecular-weight liquid crystal compounds can be used. A high-molecular-weight liquid crystal compound is a polymer having a side chain corresponding to the low-molecular-weight liquid crystal compound as described above. An optical compensatory sheet using a polymer liquid crystal compound is described in JP-A-5-53016.

As the discotic liquid crystal compound, C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives, C.I. Destrade et al., Mol. Cryst. 122, 141 (1985); Physicslett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, 70 (1984) and the cyclohexane derivative described in J. Am. M. In the report of Lehn et al., J. Am. Chem. Commun. , 1794 (1985); In the report of Zhang et al., J. Am. Am. Chem. Soc. 116, 2655 (1994) include azacrown-based and phenylacetylene-based macrocycles.

The molecule of the discotic liquid crystal compound exhibits liquid crystallinity, which is a structure in which straight-chain alkyl groups, alkoxy groups, and substituted benzoyloxy groups are substituted radially as side chains of the mother core at the center of the molecule. Compounds are also included. Molecules or aggregates of molecules are preferably compounds that have rotational symmetry and can be given a certain orientation. A retardation layer formed from a composition containing a discotic liquid crystal compound does not need to exhibit liquid crystallinity in the state of being finally included in the retardation layer. For example, when a low-molecular discotic liquid crystalline molecule having a group that reacts with heat or light is subjected to a polymerization reaction or the like by heating or light irradiation to obtain a high molecular weight, the liquid crystallinity is lost. Of course, a retardation layer containing can also be used in the present invention. Preferred examples of discotic liquid crystal compounds include compounds described in JP-A-8-50206. The polymerization of discotic liquid crystalline molecules is described in JP-A-8-27284.

In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. The discotic core and the polymerizable group are preferably a compound that bonds via a linking group, so that the alignment state can be maintained even during the polymerization reaction. For example, compounds described in Paragraph Nos. [0151] to [0168] in JP-A-2000-155216 can be mentioned.

In the present invention, from the viewpoint of improving the color in the oblique direction, the first optically anisotropic film is an optically anisotropic layer (hereinafter referred to as "optically anisotropic It is also abbreviated as the “active layer (A)”).

In addition, the in-plane retardation of the first optically anisotropic film at a wavelength of 550 nm is preferably 140 to 220 nm. 150 to 200 nm is more preferable in terms of further suppressing the tint of black (hereinafter also simply referred to as "the point of further suppressing the tint of black").

The refractive index of the first optically anisotropic film is preferably 1.50 or more and 1.70 or less, more preferably 1.55 or more and 1.55 or more, from the viewpoint of increasing the refractive index anisotropy and making the film thinner. It is more preferably 65 or less.

In the present invention, the angle formed by the in-plane slow axis of the first optically anisotropic film and the absorption axis of the polarizer is preferably 40 to 85°, more preferably 50 to 85°, and 65 to 85°. is more preferred.

When the antireflection film of the present invention is elongated, the angle formed by the longitudinal direction of the antireflection film and the in-plane slow axis of the first optically anisotropic film is preferably 40 to 85°. ~85° is more preferred, and 65 to 85° is even more preferred.

[Second optically anisotropic film]
The second optically anisotropic film of the antireflection film of the present invention has an optically anisotropic layer in which an oriented liquid crystal compound is fixed.
Here, the same liquid crystal compound as described in the first optically anisotropic film can be used.

In the present invention, the second optically anisotropic film preferably comprises two or more optically anisotropic layers from the viewpoint of improving reflectance and color in oblique directions. An optically anisotropic layer (hereinafter also abbreviated as "optically anisotropic layer (B)") comprising a twisted rod-shaped liquid crystal compound fixed as a helical axis, and a vertically aligned rod-shaped liquid crystal compound fixed. More preferably, it is composed of a laminate with an optically anisotropic layer (hereinafter also abbreviated as “optically anisotropic layer (C)”).

<Optically Anisotropic Layer (B)>
As described above, the optically anisotropic layer (B) is an optically anisotropic layer formed by fixing a twisted rod-like liquid crystal compound having a helical axis in the thickness direction, and has a so-called chiral nematic phase having a helical structure. It is preferably a fixed layer. When forming the above phase, it is preferable to use a mixture of a liquid crystal compound exhibiting a nematic liquid crystal phase and a chiral agent to be described later.

The product Δnd of the refractive index anisotropy Δn of the optically anisotropic layer (B) measured at a wavelength of 550 nm and the thickness d of the optically anisotropic layer (B) is preferably 140 to 220 nm, and has a black tint. 150 to 210 nm is more preferable, and 160 to 200 nm is even more preferable, in terms of further suppressing sticking.
The refractive index anisotropy Δn means the refractive index anisotropy of the optically anisotropic layer.
The above Δnd is measured using an AxoScan (polarimeter) device manufactured by Axometrics using the company's device analysis software.

The twist angle of the liquid crystal compound (the twist angle of the orientation direction of the liquid crystal compound) is preferably 90±30° (in the range of 60 to 120°), and is preferably 90±20° ( 70 to 110°) is more preferable, and 90±10° (within the range of 80 to 100°) is even more preferable.
The torsion angle is measured using an AxoScan (polarimeter) device manufactured by Axometrics using the company's device analysis software.
In addition, the twist alignment of the liquid crystal compound means that the liquid crystal compound is twisted from one main surface to the other main surface of the optically anisotropic layer (B) about the thickness direction of the optically anisotropic layer (B). intended to be Accordingly, the alignment direction (in-plane slow axis direction) of the liquid crystal compound varies depending on the position in the thickness direction of the optically anisotropic layer (B).

(Chiral agent (chiral agent))
Various known chiral agents can be used as the chiral agent used to form the twisted alignment of the liquid crystal compound. A chiral agent has a function of inducing a helical structure of a liquid crystal compound. The chiral compound may be selected depending on the purpose, since the induced helical sense or helical pitch differs depending on the compound.
A known compound can be used as the chiral agent, but it preferably has a cinnamoyl group. Examples of chiral agents include Liquid Crystal Device Handbook (Chapter 3, Section 4-3, Chiral Agents for TN and STN, page 199, Japan Society for the Promotion of Science, 142nd Committee, 1989), and JP-A-2003-287623. Publications, JP-A-2002-302487, JP-A-2002-80478, JP-A-2002-80851, JP-A-2010-181852 and JP-A-2014-034581 and the like are exemplified. be.

A chiral agent generally contains an asymmetric carbon atom, but an axially chiral compound or planar chiral compound that does not contain an asymmetric carbon atom can also be used as the chiral agent. Examples of axially or planarly chiral compounds include binaphthyl, helicene, paracyclophane and derivatives thereof. The chiral agent may have a polymerizable group.
When both the chiral agent and the liquid crystal compound have a polymerizable group, the polymerization reaction of the polymerizable chiral agent and the polymerizable liquid crystal compound produces a repeating unit derived from the polymerizable liquid crystal compound and a repeating unit derived from the chiral agent. can form a polymer having repeating units with In this aspect, the polymerizable group possessed by the polymerizable chiral agent is preferably the same type of group as the polymerizable group possessed by the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is also preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Especially preferred.
Also, the chiral agent may be a liquid crystal compound.

As chiral agents, isosorbide derivatives, isomannide derivatives, binaphthyl derivatives, and the like can be preferably used. As the isosorbide derivative, a commercially available product such as LC-756 manufactured by BASF may be used.
The content of the chiral agent in the liquid crystal composition is preferably 0.01 to 200 mol %, more preferably 1 to 30 mol % of the amount of the liquid crystal compound.

<Optically Anisotropic Layer (C)>
The optically anisotropic layer (C) is a layer formed by fixing a vertically aligned rod-like liquid crystal compound, and preferably a layer containing a photo-alignable polymer described later.
The in-plane retardation of the optically anisotropic layer (C) at a wavelength of 550 nm is preferably 0 to 10 nm.
Further, the retardation in the thickness direction of the optically anisotropic layer (C) at a wavelength of 550 nm is preferably -120 to -20 nm.
The in-plane retardation is more preferably 0 to 5 nm in terms of further suppressing black tint.
The retardation in the thickness direction is more preferably −110 to −30 nm, more preferably −100 to −40 nm, in terms of further suppressing black tint.

The antireflection film of the present invention has, as the first optically anisotropic film, an optically anisotropic layer (A) formed by fixing a vertically aligned discotic liquid crystal compound, and the second optically anisotropic film. and an optically anisotropic layer (B) in which a twisted rod-shaped liquid crystal compound having a helical axis in the thickness direction is fixed, and an optically anisotropic layer (C) in which a vertically aligned rod-shaped liquid crystal compound is fixed. (hereinafter abbreviated as "specific embodiment") having two layers of is preferred.

The specific aspect described above will be described with reference to FIGS. 1 to 3. FIG.
FIG. 1 is a schematic cross-sectional view of one embodiment of an antireflection film 100. FIG.
2 shows the absorption axis of the polarizer 20 and the in-plane retardation of the optically anisotropic layer (A) 12 and the optically anisotropic layer (B) 14 in the antireflection film 100 shown in FIG. It is a figure which shows the relationship with an axis|shaft. The arrow in the polarizer 20 in FIG. 2 indicates the absorption axis, and the arrow in the optically anisotropic layer (A) 12 and the optically anisotropic layer (B) 14 indicates the in-plane slow axis in each layer. represents
3 shows the absorption axis (broken line) of the polarizer 20 and the respective absorption axes of the optically anisotropic layer (A) 12 and the optically anisotropic layer (B) 14 when observed from the white arrow in FIG. It is a figure which shows the relationship of the angle with an in-plane slow axis (solid line).
The rotation angle of the in-plane slow axis is positive in the counterclockwise direction and negative in the clockwise direction, with the absorption axis of the polarizer 20 as the reference (0°) when observed from the white arrow in FIG. is expressed as an angle value of
The twist direction of the liquid crystal compound is the in-plane slow axis on the front side (polarizer 20 side) surface of the optically anisotropic layer (B) 14 when observed from the white arrow in FIG. The right twist (clockwise) or the left twist (counterclockwise) is determined based on .

As shown in FIG. 1, the antireflection film 100 includes a polarizer 20, an optically anisotropic layer (A) 12, an optically anisotropic layer (B) 14, and an optically anisotropic layer (C) 16. in that order. The antireflection film of the present invention has a specific adhesive layer (not shown) between the optically anisotropic layer (A) 12 and the optically anisotropic layer (B) 14 .
As shown in FIGS. 2 and 3, the angle φa1 between the absorption axis of the polarizer 20 and the in-plane slow axis of the optically anisotropic layer (A) 12 is 76°. More specifically, the in-plane slow axis of the optically anisotropic layer (A) 12 is rotated by −76° (76° clockwise) with respect to the absorption axis of the polarizer 20 . 2 and 3 show an aspect in which the in-plane slow axis of the optically anisotropic layer (A) 12 is at -76°, but the present invention is not limited to this aspect, and is -40°. It is preferably within the range of -85°, more preferably within the range of -50° to -85°, and even more preferably within the range of -65° to -85°. That is, the angle between the absorption axis of the polarizer 20 and the in-plane slow axis of the optically anisotropic layer (A) 12 is preferably within the range of 40 to 85°, more preferably within the range of 50 to 85°. and more preferably in the range of 65 to 85°.
As shown in FIG. 2, in the optically anisotropic layer (A) 12, the in-plane slow axis and the optical anisotropic The in-plane slow axis at the surface 122 of the optical layer (A) 12 on the optically anisotropic layer (B) 14 side is parallel.

As shown in FIGS. 2 and 3, the in-plane slow axis of the optically anisotropic layer (A) 12 and the surface 141 of the optically anisotropic layer (B) 14 on the side of the optically anisotropic layer (A) 12 is parallel to the in-plane slow axis at .
The present invention is not limited to this embodiment, and the in-plane slow axis of the optically anisotropic layer (A) 12 and the optically anisotropic layer (A) 12 side of the optically anisotropic layer (B) 14 The angle formed with the in-plane slow axis on the surface 141 is preferably within the range of 0 to 20°.
The optically anisotropic layer (B) 14 is, as described above, an optically anisotropic layer formed by fixing a rod-like liquid crystal compound twisted with its helical axis in the thickness direction. Therefore, as shown in FIGS. 2 and 3, the in-plane slow axis on the surface 141 of the optically anisotropic layer (B) 14 on the side of the optically anisotropic layer (A) 12 The in-plane slow axis on the surface 142 opposite to the optically anisotropic layer (A) 12 of B) 14 forms the above-described twist angle (81° in FIG. 2). That is, the in-plane slow axis on the surface 141 of the optically anisotropic layer (B) 14 on the side of the optically anisotropic layer (A) 12 and the optically anisotropic layer (B) 14 of the optically anisotropic layer (B) 14 A) The angle φ2 between the surface 142 opposite to the 12 side and the in-plane slow axis is 81°. More specifically, the twist direction of the rod-like liquid crystal compound in the optically anisotropic layer (B) 14 is left twist (counterclockwise), and the twist angle is 81°.
2 and 3 show an embodiment in which the rod-like liquid crystal compound in the optically anisotropic layer (B) 14 has a twist angle of 81°, but the present invention is not limited to this embodiment. The twist angle of the compound is preferably within the range of 80±30°. That is, the in-plane slow axis on the surface 141 of the optically anisotropic layer (B) 14 on the side of the optically anisotropic layer (A) 12 and the optically anisotropic layer (B) 14 of the optically anisotropic layer (B) 14 A) The angle formed by the in-plane slow axis on the surface 142 opposite to the 12 side is preferably within the range of 80±30°.

As described above, in the embodiments of FIGS. 2 and 3, when the antireflection film 100 is observed from the polarizer 20 side, the absorption axis of the polarizer 20 is used as a reference for the optically anisotropic layer (A) 12. The in-plane slow axis is rotated clockwise by 76°, and the twist direction of the rod-like liquid crystal compound in the optically anisotropic layer (B) 14 is counterclockwise (left twist).
In FIGS. 2 and 3, the twist direction of the rod-like liquid crystal compound is counterclockwise, but it may be twisted clockwise as long as it satisfies a predetermined angle relationship. More specifically, when the antireflection film 100 is observed from the polarizer 20 side, the in-plane slow axis of the optically anisotropic layer (A) 12 is counterclockwise with respect to the absorption axis of the polarizer 20. The twist direction of the rod-like liquid crystal compound in the optically anisotropic layer (B) 14 may be clockwise (right twist).

That is, in the antireflection film 100 shown in FIG. 1, when the antireflection film 100 is observed from the polarizer 20 side, the in-plane retardation of the optically anisotropic layer (A) is based on the absorption axis of the polarizer 20. When the phase axis rotates clockwise within the range of 40 to 85° (preferably 50 to 85°, more preferably 65 to 85°), the optically anisotropic layer of the optically anisotropic layer (B) The twist direction of the rod-like liquid crystal compound in the optically anisotropic layer (B) is preferably counterclockwise with respect to the in-plane slow axis on the (A) side surface.
In the antireflection film 100 shown in FIG. 1, when the antireflection film 100 is observed from the polarizer 20 side, the in-plane retardation of the optically anisotropic layer (A) is measured with the absorption axis of the polarizer 20 as a reference. When the phase axis rotates counterclockwise within the range of 40 to 85° (preferably 50 to 85°, more preferably 65 to 85°), the optical anisotropy of the optically anisotropic layer (B) The twist direction of the rod-like liquid crystal compound in the optically anisotropic layer (B) is preferably clockwise with respect to the in-plane slow axis on the surface of the layer (A). Even when the twist direction of the rod-like liquid crystal compound in the optically anisotropic layer (B) is clockwise, the in-plane slow axis of the optically anisotropic layer (A) and the optically anisotropic layer (B ) with the in-plane slow axis on the surface of the optically anisotropic layer (A) is preferably in the range of 0 to 20°.

[Adhesion layer]
The antireflection film of the present invention may have an adhesion layer other than the specific adhesive layer described above, for example, between the polarizer and the first optically anisotropic film.
Examples of the adhesion layer include known pressure-sensitive adhesive layers and adhesive layers.

[Method for producing antireflection film]
The method for producing the antireflection film of the present invention is not particularly limited, and known methods can be employed.
For example, a first optically anisotropic film and a second optically anisotropic film exhibiting predetermined optical properties are prepared, respectively, and optically anisotropic layers and substrates (for example, long supports) constituting these films are prepared. body, etc.) in a predetermined order via a specific pressure-sensitive adhesive layer, a pressure-sensitive adhesive layer, or an adhesive layer, an antireflection film can be produced.
Moreover, you may combine the method of bonding mentioned above, and the method of forming an optically anisotropic layer using the composition for optically anisotropic layer forming.
As a combined method, a composition for forming an optically anisotropic layer is coated on a long support, and an optically anisotropic layer constituting a second optically anisotropic film (for example, the above-mentioned optically anisotropic After forming the optically anisotropic layer (C) and the optically anisotropic layer (B)) to obtain a laminate, a first layer formed by separately coating the composition for forming an optically anisotropic layer on the substrate is formed. An antireflection film can be produced by laminating an optically anisotropic layer constituting an optically anisotropic film (for example, the optically anisotropic layer (A) described above) via a specific pressure-sensitive adhesive layer. .
The substrate, the composition for forming an optically anisotropic layer, and the like are described in detail below.

<Substrate>
A transparent substrate is preferable as the substrate. The transparent substrate means a substrate having a visible light transmittance of 60% or more, preferably 80% or more, more preferably 90% or more.

The thickness direction retardation value (Rth(550)) of the substrate at a wavelength of 550 nm is not particularly limited, but is preferably −110 to 110 nm, more preferably −80 to 80 nm.
The in-plane retardation value (Re(550)) of the substrate at a wavelength of 550 nm is not particularly limited, but is preferably 0 to 50 nm, more preferably 0 to 30 nm, even more preferably 0 to 10 nm.

As a material for forming the substrate, a polymer that is excellent in optical performance transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, and the like is preferable.
Polymer films that can be used as substrates include, for example, cellulose acylate films (e.g., cellulose triacetate film (refractive index: 1.48), cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate propionate film), Polyolefin films such as polyethylene and polypropylene, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyethersulfone films, polyacrylic films such as polymethylmethacrylate, polyurethane films, polycarbonate films, polysulfone films, polyether films, polymethylpentene films , polyether ketone film, (meth)acrylonitrile film, and polymer film having an alicyclic structure (norbornene resin (Arton: trade name, manufactured by JSR Corporation, amorphous polyolefin (Zeonex: trade name, Nippon Zeon company))).
Among them, triacetyl cellulose, polyethylene terephthalate, or a polymer having an alicyclic structure is preferable as the material for the polymer film, and triacetyl cellulose is more preferable.

The substrate may contain various additives (for example, optically anisotropic modifiers, wavelength dispersion modifiers, fine particles, plasticizers, UV inhibitors, deterioration inhibitors, release agents, etc.).

The thickness of the substrate is not particularly limited, but is preferably 10 to 200 μm, more preferably 10 to 100 μm, even more preferably 20 to 90 μm. Also, the substrate may consist of a laminate of a plurality of sheets. The substrate may be subjected to a surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment) on the surface of the substrate to improve adhesion with the layer provided thereon.
Further, an adhesive layer (undercoat layer) may be provided on the substrate.
In addition, inorganic particles with an average particle size of about 10 to 100 nm are added to the substrate as a solid content in order to provide slipperiness during the transportation process and to prevent sticking between the back surface and the front surface after winding. A polymer layer mixed with 5 to 40 mass % by mass ratio may be arranged on one side of the substrate.

The substrate may be a so-called temporary support. In other words, the substrate may be peeled off from the optically anisotropic layer after the antireflection film of the invention is produced.

Alternatively, the surface of the substrate may be directly rubbed. That is, a substrate subjected to rubbing treatment may be used. The direction of the rubbing treatment is not particularly limited, and an optimum direction is appropriately selected according to the direction in which the liquid crystal compound is to be oriented.
For the rubbing treatment, a treatment method that is widely employed as a liquid crystal alignment treatment step for LCDs (liquid crystal displays) can be applied. That is, a method of obtaining orientation can be used by rubbing the surface of the substrate in a given direction with paper, gauze, felt, rubber, nylon fiber, polyester fiber, or the like.

An alignment film may be arranged on the substrate.
The alignment film is formed by rubbing an organic compound (preferably polymer), oblique vapor deposition of an inorganic compound, formation of a layer having microgrooves, or organic compound (eg, ω-tricosane) by the Langmuir-Blodgett method (LB film). acid, dioctadecylmethylammonium chloride, methyl stearate).
Furthermore, an alignment film is also known, in which an alignment function is produced by application of an electric field, application of a magnetic field, or light irradiation (preferably polarized light).
The alignment film also includes a photo-alignment film.
The thickness of the alignment film is not particularly limited as long as the alignment function can be exhibited. preferable.
The alignment film may be peelable from the optically anisotropic layer together with the substrate.

<Composition for forming an optically anisotropic layer>
The liquid crystal compound contained in the composition for forming an optically anisotropic layer is as described above. As described above, the rod-like liquid crystal compound and the discotic liquid crystal compound are appropriately selected according to the properties of the optically anisotropic layer to be formed.
The content of the polymerizable liquid crystal compound in the composition for forming an optically anisotropic layer is preferably 60 to 99% by mass, more preferably 70 to 98% by mass, based on the total solid content of the composition for forming an optically anisotropic layer. is more preferred.
The solid content means a component capable of forming an optically anisotropic layer from which the solvent has been removed.

The composition for forming an optically anisotropic layer may contain compounds other than the polymerizable liquid crystal compound.
For example, the optically anisotropic layer-forming composition for forming the optically anisotropic layer (B) described above preferably contains a chiral agent in order to twist-align the liquid crystal compound.
Moreover, the optically anisotropic layer-forming composition for forming the optically anisotropic layer (C) described above preferably contains a photo-orientable polymer.

The composition for forming an optically anisotropic layer may contain a polymerization initiator. The polymerization initiator to be used is selected according to the type of polymerization reaction, and examples thereof include thermal polymerization initiators and photopolymerization initiators.
The content of the polymerization initiator in the composition for forming an optically anisotropic layer is preferably 0.01 to 20% by mass, more preferably 0.5 to 20% by mass, based on the total solid content of the composition for forming an optically anisotropic layer. 10% by mass is more preferred.

Other components that may be contained in the composition for forming an optically anisotropic layer include, in addition to the above, polyfunctional monomers, alignment control agents (vertical alignment agents, horizontal alignment agents), surfactants, and adhesion improvement. agents, plasticizers, and solvents.

<Method for Forming Optically Anisotropic Layer>
The procedure for forming the optically anisotropic layer is not particularly limited. Also referred to as "coating method".) and the like.

The coating method is not particularly limited, and examples thereof include wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, and die coating.
In addition, after coating the composition, the coating film coated on the substrate may be dried, if necessary. The solvent can be removed from the coating film by performing a drying treatment.

Although the film thickness of the coating film is not particularly limited, it is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, and even more preferably 0.5 to 10 μm.

Next, the formed coating film is subjected to alignment treatment to align the polymerizable liquid crystal compound in the coating film.
The orientation treatment can be performed by drying the coating film at room temperature or by heating the coating film. In the case of a thermotropic liquid crystal compound, the liquid crystal phase formed by alignment treatment can generally be caused to transition by a change in temperature or pressure. In the case of a lyotropic liquid crystal compound, the transition can also be achieved by changing the composition ratio such as the amount of solvent.
The conditions for heating the coating film are not particularly limited, but the heating temperature is preferably 50 to 250° C., more preferably 50 to 150° C., and the heating time is preferably 10 seconds to 10 minutes.
Moreover, after heating the coating film, the coating film may be cooled, if necessary, before the curing treatment (light irradiation treatment) to be described later. The cooling temperature is preferably 20 to 200°C, more preferably 30 to 150°C.

Next, the coating film in which the polymerizable liquid crystal compound is oriented is subjected to a curing treatment.
There are no particular limitations on the method of curing treatment performed on the coating film in which the polymerizable liquid crystal compound is oriented, and examples thereof include light irradiation treatment and heat treatment. Among them, light irradiation treatment is preferable, and ultraviolet irradiation treatment is more preferable, from the viewpoint of production aptitude.
The irradiation conditions for the light irradiation treatment are not particularly limited, but an irradiation amount of 50 to 1000 mJ/cm ² is preferable.
Although the atmosphere during the light irradiation treatment is not particularly limited, a nitrogen atmosphere is preferred.

Moreover, when the optically anisotropic layer contains a photo-alignable polymer, it is preferable to perform a photo-alignment treatment from the viewpoint of imparting alignment controllability.
As the photo-alignment treatment, for example, a coating film (including a cured film subjected to a curing treatment) of the polymerizable liquid crystal composition is irradiated with polarized light, or the coating film surface is irradiated with non-polarized light from an oblique direction. is mentioned.

In the photo-alignment treatment, the polarized light to be irradiated is not particularly limited, and examples thereof include linearly polarized light, circularly polarized light, and elliptically polarized light, with linearly polarized light being preferred.
In addition, the “oblique direction” in which non-polarized light is irradiated is not particularly limited as long as it is a direction inclined at a polar angle θ (0<θ<90°) with respect to the normal direction of the coating film surface, depending on the purpose. θ is preferably 20 to 80°.

The wavelength of polarized light or non-polarized light is not particularly limited as long as it is light to which the photo-orientation group is sensitive.
Light sources for polarized or non-polarized light irradiation include, for example, xenon lamps, high-pressure mercury lamps, extra-high pressure mercury lamps, and metal halide lamps. By using an interference filter or a color filter for the ultraviolet light or visible light obtained from such a light source, the wavelength range to be irradiated can be limited. In addition, by using a polarizing filter or a polarizing prism for the light from these light sources, linearly polarized light can be obtained.

The integrated amount of polarized or unpolarized light is not particularly limited, and is preferably 1 to 300 mJ/cm ² , more preferably 5 to 100 mJ/cm ² .
The illuminance of polarized or unpolarized light is not particularly limited, and is preferably 0.1-300 mW/cm ² , more preferably 1-100 mW/cm ² .

[Organic EL display device]
The organic EL display device of the present invention has the antireflection film described above. An antireflection film is usually provided on an organic EL display panel of an organic EL display device. That is, the organic EL display device of the present invention has an organic EL display panel and the antireflection film described above.

An organic EL display panel is a member in which a light-emitting layer or a plurality of organic compound thin films including a light-emitting layer are formed between a pair of electrodes of an anode and a cathode. It may have a layer, an electron transport layer, a protective layer, etc., and each of these layers may have other functions. Various materials can be used to form each layer.

The features of the present invention will be described more specifically below with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, and processing procedures shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed to be limited by the specific examples shown below.

[Example 1-1]
<Preparation of cellulose acylate film (substrate)>
The following composition was put into a mixing tank, stirred, and heated at 90° C. for 10 minutes. Thereafter, the resulting composition was filtered through a filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope. The solid content concentration of the dope was 23.5% by mass, the amount of the plasticizer added was the ratio to the cellulose acylate, and the dope solvent was methylene chloride/methanol/butanol = 81/18/1 (mass ratio). .

―――――――――――――――――――――――――――――――――
Cellulose acylate dope――――――――――――――――――――――――――――――――――
Cellulose acylate (acetyl substitution degree 2.86, viscosity average polymerization degree 310)
100 parts by mass sugar ester compound 1 (represented by formula (S4) below) 6.0 parts by mass sugar ester compound 2 (represented by formula (S5) below) 2.0 parts by mass silica particle dispersion (AEROSIL R972, Nippon Aerosil ( Co., Ltd.)
0.1 part by mass solvent (methylene chloride/methanol/butanol)
―――――――――――――――――――――――――――――――――

The dope prepared above was cast using a drum film-forming machine. The dope was cast from a die in contact with a metal support cooled to 0° C., after which the resulting web (film) was stripped off. The drum was made of SUS (Steel Use Stainless).

The web (film) obtained by casting is peeled off from the drum, and dried for 20 minutes in a tenter device using a tenter device in which both ends of the web are clipped and conveyed at 30 to 40 ° C. during film transportation. did. Subsequently, the web was post-dried by zone heating while being rolled. The resulting web was knurled and wound up.
The resulting cellulose acylate film had a thickness of 40 μm, an in-plane retardation Re(550) of 1 nm at a wavelength of 550 nm, and a thickness direction retardation Rth(550) of 26 nm at a wavelength of 550 nm.
(Alkaline saponification treatment)
The above cellulose acylate film was passed through a dielectric heating roll at a temperature of 60°C to raise the film surface temperature to 40°C, and then an alkaline solution having the composition shown below was applied to the band surface of the film using a bar coater. The coating was applied at a coating amount of 14 ml/m ² with a drier, and conveyed for 10 seconds under a steam type far-infrared heater manufactured by Noritake Co., Ltd. which was heated to 110°C. Subsequently, using the same bar coater, 3 ml/m ² of pure water was applied. Next, after repeating water washing with a fountain coater and draining with an air knife three times, the film was transported to a drying zone at 70° C. for 10 seconds and dried to prepare a cellulose acylate film saponified with an alkali.

――――――――――――――――――――――――――――――――
Alkaline solution ――――――――――――――――――――――――――――――
Potassium hydroxide 4.7 parts by weight Water 15.8 parts by weight _Isopropanol 63.7 parts _by weight Surfactant: _C14H29O ( _CH2CH2O ) _20H 1.0 parts by weight Propylene glycol 14.8 parts by weight ――――――――――――――――――――――――――――――――

<Formation of Alignment Film>
An orientation film coating solution having the following composition was continuously applied to the alkali-saponified surface of the cellulose acylate film using a #14 wire bar. It was dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds.

――――――――――――――――――――――――――――――――
Alignment film coating solution――――――――――――――――――――――――――――――――
The following polyvinyl alcohol 10 parts by mass Water 371 parts by mass Methanol 119 parts by mass Glutaraldehyde (crosslinking agent) 0.5 parts by mass Citric acid ester (manufactured by Sankyo Chemical Co., Ltd.) 0.175 parts by mass ――――――――――――――――――――――――

polyvinyl alcohol

<Formation of optically anisotropic layer (A)>
The alignment film prepared above was continuously subjected to rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the conveying direction, and the angle formed by the longitudinal direction of the film (conveying direction) and the rotation axis of the rubbing roller was 76°. If the longitudinal direction (conveyance direction) of the film is 90° and the clockwise direction is represented by a positive value with the film width direction as the reference (0°) observed from the film side, the rotation axis of the rubbing roller is −14°. It is in. In other words, the position of the rotation axis of the rubbing roller is the position rotated counterclockwise by 76° with respect to the longitudinal direction of the film.

An optically anisotropic layer coating solution (1a) containing a discotic liquid crystal compound having the following composition was applied onto the rubbed alignment film using a Giesser coater to form a composition layer. Thereafter, the resulting composition layer was heated with hot air at 110° C. for 2 minutes to dry the solvent and ripen the alignment of the discotic liquid crystal compound. Subsequently, the obtained composition layer was irradiated with UV (500 mJ/cm ² ) at 80° C. to fix the orientation of the liquid crystal compound, and the optical anisotropic layer corresponding to the optically anisotropic layer (A) was applied. A layer (1a) was formed.
The thickness of the optically anisotropic layer (1a) was 1.5 μm. Also, the retardation at 550 nm was 168 nm. The average inclination angle of the discotic surface of the discotic liquid crystal compound with respect to the film plane was 90°, and it was confirmed that the liquid crystal compound was oriented perpendicularly to the film plane. The angle of the slow axis of the optically anisotropic layer (1a) is parallel to the rotation axis of the rubbing roller, and the width direction of the film is 0° (the longitudinal direction is 90° counterclockwise and -90° clockwise). ), the slow axis was −14° when viewed from the optically anisotropic layer (1a) side.

――――――――――――――――――――――――――――――――
Optically anisotropic layer-forming composition (1a)
――――――――――――――――――――――――――――――――
Discotic liquid crystal compound 1 below 80 parts by mass Discotic liquid crystal compound 2 below 20 parts by mass Alignment film interface alignment agent 1 below 0.55 parts by mass 0.05 parts by mass of the following fluorine-containing compound C 0.21 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Co., Ltd.) 10 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by BASF ) 3.0 parts by mass Methyl ethyl ketone 200 parts by mass ――――――――――――――――――――――――――――――――

Discotic liquid crystal compound 1

Discotic liquid crystal compound 2

Alignment film interface alignment agent 1

Fluorine-containing compound A (in the following formula, a and b represent the content (% by mass) of each repeating unit with respect to all repeating units, a represents 90% by mass, and b represents 10% by mass. In addition, the weight average molecular weight was 15,000.)

Fluorine-containing compound B (The numerical value in each repeating unit represents the content (% by mass) with respect to all repeating units. The weight average molecular weight was 12,500.)

Fluorine-containing compound C (The numerical value in each repeating unit represents the content (% by mass) with respect to all repeating units. The weight average molecular weight was 12,500.)

<Laminate formation of optically anisotropic layer (C) and optically anisotropic layer (B)>
(Formation of optically anisotropic layer (1c))
An optically anisotropic layer coating solution (1c) containing a rod-like liquid crystal compound having the following composition was applied onto the cellulose acylate film prepared above using a Giesser coater to form a composition layer. After that, both ends of the film were held, and a cooling plate (9°C) was placed on the side of the film on which the coating film was formed so that the distance from the film was 5 mm, and the coating film of the film was formed. A heater (75° C.) was installed on the side opposite to the surface so that the distance from the film was 5 mm, and dried for 2 minutes.
Then, it was heated with hot air at 60° C. for 1 minute, and irradiated with UV rays of 100 mJ/cm ² using a UV-LED of 365 nm while purging with nitrogen so that the atmosphere had an oxygen concentration of 100 ppm or less. After that, the precursor layer was formed by annealing for 1 minute at 120° C. with hot air.
At room temperature, the obtained precursor layer was irradiated with UV light (ultra-high pressure mercury lamp; UL750; manufactured by HOYA) at 7.9 mJ/cm ² (wavelength: 313 nm) through a wire grid polarizer. A composition layer having alignment controllability was formed.
The film thickness of the formed composition layer was 0.5 μm. The in-plane retardation Re at a wavelength of 550 nm was 0 nm, and the thickness direction retardation Rth at a wavelength of 550 nm was -68 nm. The average tilt angle of the long axis direction of the rod-like liquid crystal compound with respect to the film surface was 90°, and it was confirmed that the compound was oriented perpendicular to the film surface.
Thus, an optically anisotropic layer (1c) corresponding to the optically anisotropic layer (C) was formed.

――――――――――――――――――――――――――――――――
Optically anisotropic layer-forming composition (1c)
――――――――――――――――――――――――――――――――
The following rod-shaped liquid crystal compound (A) 100 parts by mass Polymerizable monomer (A-400, manufactured by Shin-Nakamura Chemical Co., Ltd.) 4.0 parts by mass The following polymerization initiator S-1 (oxime type) 5.0 parts by mass The following Photoacid generator D-1 3.0 parts by mass Polymer M-1 2.0 parts by mass Vertical alignment agent S01 below 2.0 parts by mass Photo-alignment polymer A-1 below 2.0 parts by mass Methyl ethyl ketone 42.3 parts by mass methyl isobutyl ketone 627.5 parts by mass ――――――――――――――――――――――――――――――――

Rod-shaped liquid crystal compound (A) (hereinafter referred to as a mixture of compounds)

Polymerization initiator S-1

Photoacid generator D-1

Polymer M-1 (The numerical value in each repeating unit represents the content (% by mass) with respect to all repeating units. The weight average molecular weight was 60000.)

Vertical alignment agent S01

Photo-alignable polymer A-1 (The numerical value described in each repeating unit represents the content (% by mass) of each repeating unit with respect to all repeating units, and from the left repeating unit, 40% by mass, 25% by mass, 35% by mass, % by mass, and the weight average molecular weight was 69,300.)

(Formation of optically anisotropic layer (1b))
Next, on the optically anisotropic layer (1c) prepared above, an optically anisotropic layer coating solution (1b) containing a rod-like liquid crystal compound having the following composition was applied using a Giesser coating machine, and the coating solution was heated at 80°C. Heated with hot air for 60 seconds. Subsequently, the obtained composition layer was irradiated with UV (500 mJ/cm ² ) at 80° C. to fix the alignment of the liquid crystal compound, and the optical anisotropic layer corresponding to the optically anisotropic layer (B) was applied. A layer (1b) was formed.
The thickness of the optically anisotropic layer (1b) was 1.2 μm, Δnd at a wavelength of 550 nm was 164 nm, and the twist angle of the liquid crystal compound was 81°. Assuming that the width direction of the film is 0° (the longitudinal direction is 90°), when viewed from the optically anisotropic layer (1b) side, the orientation axis angle of the liquid crystal compound is 14° on the air side and 14° on the optically anisotropic layer ( The side contacting 1c) was 95°.
The orientation axis angle of the liquid crystal compound contained in the optically anisotropic layer was determined by observing the substrate from the surface side of the optically anisotropic layer, with the width direction of the substrate being 0° as a reference, and rotating clockwise (clockwise). Hour is expressed as negative and counterclockwise (counterclockwise) hour as positive.
The twist angle of the liquid crystal compound is determined by observing the substrate from the surface side of the optically anisotropic layer, and using the orientation axis direction of the liquid crystal compound on the surface side (front side) as a reference, the liquid crystal compound on the substrate side (back side). When the direction of the orientation axis is clockwise (right), it is indicated as negative, and when it is counterclockwise (left), it is indicated as positive.

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Optically anisotropic layer-forming composition (1b)
――――――――――――――――――――――――――――――――
Rod-shaped liquid crystal compound (A) above 70 parts by weight Rod-shaped liquid crystal compound (B) below 30 parts by weight Ethylene oxide-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Co., Ltd.) 4 parts by weight Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass Left-handed chiral agent (L1) below 0.50 parts by mass Fluorinated compound D below 0.20 parts by mass Methyl isobutyl ketone 126 parts by mass Ethyl propionate 126 parts by mass --- ―――――――――――――――――――――――――――――

Rod-shaped liquid crystal compound (B)

Left-handed chiral agent (L1) [In the following formula, Bu represents a butyl group. ]

Fluorine-containing compound D (the numerical value in each repeating unit represents the content (% by mass) of all repeating units, the content of the repeating unit on the left is 76% by mass, and the content of the repeating unit on the right is 24% by mass. Also, the weight average molecular weight was 27,300.)

A laminate (1c-1b) in which the optically anisotropic layer (1c) and the optically anisotropic layer (1b) were directly laminated on the elongated cellulose acylate film was produced by the above procedure. When the surface of the optically anisotropic layer (1c) in contact with the optically anisotropic layer (1b) was confirmed by the method described above, it was confirmed that the photo-alignable polymer was present.

<Laminate formation of optically anisotropic layer (A), optically anisotropic layer (B) and optically anisotropic layer (C)>
The surface side of the optically anisotropic layer (1a) formed on the elongated cellulose acylate film prepared above, and the laminate (1c-1b) formed on the elongated cellulose acylate film prepared above. and the surface side of the optically anisotropic layer (1b) were laminated on a continuous machine using a 5 μm-thick acrylic adhesive (NCF-D692, manufactured by Lintec).
Subsequently, the cellulose acylate film and alignment film on the optically anisotropic layer (1a) side were peeled off to expose the surface of the optically anisotropic layer (1a) in contact with the cellulose acylate film. Thus, an optical film in which the optically anisotropic layer (1c), the optically anisotropic layer (1b), and the optically anisotropic layer (1a) are laminated in this order on the long cellulose acylate film. (1c-1b-1a) were obtained.

<Production of linear polarizing plate 1>
The surface of the support of a cellulose triacetate film TJ25 (manufactured by Fuji Film Co., Ltd.; thickness 25 μm) was saponified with an alkali. Specifically, the support was immersed in a 1.5 N sodium hydroxide aqueous solution at 55° C. for 2 minutes, washed in a water washing bath at room temperature, and further treated with 0.1 N sulfuric acid at 30° C. neutralized using After neutralization, the support was washed in a water washing bath at room temperature and dried with warm air at 100° C. to obtain a polarizer protective film.
A rolled polyvinyl alcohol (PVA) film with a thickness of 60 μm was continuously stretched in the iodine aqueous solution in the longitudinal direction and dried to obtain a polarizer with a thickness of 13 μm. The luminous efficiency correction single transmittance of the polarizer was 43%. At this time, the absorption axis direction and the longitudinal direction of the polarizer coincided.
The above polarizer protective film was attached to one surface of the above polarizer using the following PVA adhesive to prepare a linear polarizing plate 1 .

(Preparation of PVA adhesive)
100 parts by mass of a polyvinyl alcohol-based resin having an acetoacetyl group (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of acetoacetylation: 5 mol%) and 20 parts by mass of methylol melamine were heated at 30°C. A PVA adhesive was prepared as an aqueous solution adjusted to a solid content concentration of 3.7% by mass by dissolving in pure water under the temperature condition of .

<Production of antireflection film>
The surface of the optically anisotropic layer (1a) of the long optical film (1c-1b-1a) produced above and the surface of the polarizer of the long linear polarizing plate produced above (polarizer protective film The opposite surface) was continuously bonded using an ultraviolet-curing adhesive. Subsequently, the cellulose acylate film on the optically anisotropic layer (1c) side was peeled off to expose the surface of the optically anisotropic layer (1c) that was in contact with the cellulose acylate film.
Thus, an antireflection film (P1) composed of the optical film (1c-1b-1a) and the linear polarizing plate was produced. At this time, the polarizer protective film, the polarizer, the optically anisotropic layer (1a), the optically anisotropic layer (1b) and the optically anisotropic layer (1c) are laminated in this order, and the absorption of the polarizer is The angle between the axis and the slow axis of the optically anisotropic layer (1a) was -76°. The orientation axis angle of the liquid crystal compound on the side of the optically anisotropic layer (1a) of the optically anisotropic layer (1b) was 14° with the width direction being 0° as a reference. coincided with the slow axis direction of

[Examples 1-2 to 1-4 and Comparative Examples 1-1 to 1-3]
An antireflection film was prepared in the same manner as in Example 1-1, except that an adhesive having a thickness and a thickness unevenness σ shown in Table 1 below was used instead of the adhesive used in Example 1-1. made.

[Example 2-1 and Comparative Example 2-1]
Instead of the adhesive used in Example 1-1, Example 1-1 was used, except that an adhesive having a thickness shown in Table 2 below and a thickness unevenness σ (nm) / thickness (μm) was used. An antireflection film was produced in the same manner.

[evaluation]
Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-3, and using the antireflection films produced in Examples 2-1 and Comparative Example 2-1 to produce an organic EL display device, The following evaluations were performed.

[Production of organic EL display device]
(Mounting on display device)
GALAXY S4 manufactured by SAMSUNG equipped with an organic EL panel is disassembled, the circularly polarizing plate is peeled off, the antireflection film prepared above is placed there, and the polarizer protective film is placed on the outside. It was attached to a display device using

[Evaluation of display performance]
(front direction)
A black display was performed on the produced organic EL display device, and the display was observed from the front direction under bright light, and the tint was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.
A: Coloring is not visually recognized at all, or is slightly visible. (acceptable)
B: Coloring is visually recognized, but the reflected light is small, and there is no problem in use. (acceptable)
C: Coloring is visually recognized, reflected light is large, and unacceptable.

(diagonal direction)
A black display was performed on the produced organic EL display device, a fluorescent lamp was projected from a polar angle of 45° under bright light, and reflected light was observed from all directions. The azimuth angle dependence of color change was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.
A: No color difference is visible at all, or it is visible, but is very slight. (acceptable)
B: Color difference is visually recognized, but reflected light is small, and there is no problem in use. (acceptable)
C: A color difference is visually recognized and reflected light is large, which is unacceptable.

(Rainbow unevenness)
The produced antireflection film was attached to a mirror using a pressure-sensitive adhesive such that the polarizer protective film was arranged on the outside. Under fluorescence (FPL-27EX-N), colors were observed from all directions through a diffusion plate. The azimuth angle dependence of color change was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.
A: No color difference is visually recognized in the plane, or it is visually recognized, but it is very slight. (acceptable)
B: Color difference is visually recognized in the plane, but there is no problem in use. (acceptable)
C: A color difference is visually recognized in the plane and is unacceptable.
D: A clearly strong color difference is visually recognized in the plane, which is unacceptable.

[Evaluation of bubbles during lamination]
A black display was performed on the produced organic EL display device, and the display was observed from the front direction and the 20° direction under bright light, and defects caused by air bubbles were evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.
Bubbles present: Clearly circular traces of color loss are present and are unacceptable.
No air bubbles: No defects are visually observed, and there is no problem in use. (acceptable)

From the results shown in Table 1, the antireflection film in which the thickness unevenness σ of the pressure-sensitive adhesive layer used for laminating the first optically anisotropic film and the second optically anisotropic film is 35 nm or more, the organic EL It was found that rainbow unevenness occurs when used in a display device (Comparative Examples 1-1 to 1-3). In addition, in Comparative Examples 1-3, the azimuth angle dependence of the tint change was strong, and the display performance in the oblique direction was inferior.
On the other hand, an antireflection film in which the thickness unevenness σ of the pressure-sensitive adhesive layer used for laminating the first optically anisotropic film and the second optically anisotropic film is less than 35 nm, the organic EL display device It was found that the occurrence of iridescent unevenness can be suppressed when used (Examples 1-1 to 1-4).
In particular, from a comparison between Examples 1-1 and 1-4, when the thickness unevenness σ of the pressure-sensitive adhesive layer is more than 3 nm, the first optically anisotropic film and the second optically anisotropic film It was found that air bubbles are less likely to enter during lamination.

From the results shown in Table 2, the ratio of the pressure-sensitive adhesive layer used for laminating the first optically anisotropic film and the second optically anisotropic film [thickness unevenness σ (nm)/thickness (μm)] was 7.0. It was found that an antireflection film with a value of more than 0 causes iridescent unevenness when used in an organic EL display device (Comparative Example 2-1).
On the other hand, the ratio of the pressure-sensitive adhesive layer used for laminating the first optically anisotropic film and the second optically anisotropic film [thickness unevenness σ (nm)/thickness (μm)] is 7.0 or less. It was found that the antireflection film can suppress the occurrence of iridescent unevenness when used in an organic EL display device (Example 2-1).

10 optical film 12 optically anisotropic layer (A)
14 optically anisotropic layer (B)
16 optically anisotropic layer (C)
20 polarizer 100 circularly polarizing plate 121, 122, 141, 142 surface

Claims (11)

1. An antireflection film comprising a polarizer, a first optically anisotropic film, and a second optically anisotropic film in this order,
   Both the first optically anisotropic film and the second optically anisotropic film have an optically anisotropic layer formed by fixing an oriented liquid crystal compound,
   The first optically anisotropic film and the second optically anisotropic film are laminated via an adhesive layer,
   The antireflection film, wherein the standard deviation σ of the film thickness value calculated when the thickness of the pressure-sensitive adhesive layer is measured by an interference film thickness meter is less than 35 nm.
2. An antireflection film comprising a polarizer, a first optically anisotropic film, and a second optically anisotropic film in this order,
   Both the first optically anisotropic film and the second optically anisotropic film have an optically anisotropic layer formed by fixing an oriented liquid crystal compound,
   The first optically anisotropic film and the second optically anisotropic film are laminated via an adhesive layer,
   The ratio of the standard deviation σ (nm) of the film thickness value calculated when the thickness of the pressure-sensitive adhesive layer is measured by an interference film thickness gauge to the thickness (μm) of the pressure-sensitive adhesive layer is 7.0 or less. , anti-reflection film.
3. The antireflection film according to claim 1, wherein the first optically anisotropic film has a refractive index of 1.50 or more and 1.70 or less.
4. The antireflection film according to claim 1, wherein the pressure-sensitive adhesive layer has a refractive index of 1.36 or more and 1.53 or less.
5. The antireflection film according to claim 1, wherein the first optically anisotropic film has an in-plane retardation of 140 to 220 nm at a wavelength of 550 nm.
6. The antireflection film is elongated,
   2. The antireflection film according to claim 1, wherein the longitudinal direction of said antireflection film forms an angle of 40 to 85° with the in-plane slow axis of said first optically anisotropic film.
7. The antireflection film according to claim 1, wherein the first optically anisotropic film is an optically anisotropic layer formed by fixing a vertically aligned discotic liquid crystal compound.
8. The antireflection film according to claim 1, wherein the second optically anisotropic film is composed of two or more optically anisotropic layers.
9. The second optically anisotropic film comprises an optically anisotropic layer in which a twisted rod-like liquid crystal compound having a helical axis in the thickness direction is fixed, and an optically anisotropic film in which a vertically aligned rod-like liquid crystal compound is fixed. 2. The antireflection film according to claim 1, which is composed of a laminate with an optical layer.
10. The antireflection film according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 2 to 20 µm.
11. An organic electroluminescence display device comprising the antireflection film according to any one of claims 1 to 10.

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