JP2019091023A - Circularly polarizing plate - Google Patents

Abstract

To provide a circularly polarizing plate with superior bending resistance while reducing color variation caused by bending.SOLUTION: A circularly polarizing plate for use in a flexible display device is provided, comprising a polarizer and at least one or more kinds of retardation layers disposed on one side of the polarizer. Hue of reflected light observed before and after bending the plate does not change in polarity across an acoordinate axis and a bcoordinate axis of abchromaticity coordinates.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a circularly polarizing plate. The present invention also relates to a bendable display device provided with such a circularly polarizing plate.

  2. Description of the Related Art Conventionally, a circularly polarizing plate is used in a display device to suppress the adverse effect of external light reflection. On the other hand, in recent years, a demand for a flexible (flexible) display device represented by an organic electroluminescence (EL) display device has been intensified. Furthermore, there is a demand not only for the pliability of the display device but also for the pliability with a very small radius of curvature.

  However, when the organic EL display is bent with a very small radius of curvature, a large force (tensile force on the outside of the bent portion and compression force on the inside of the bent portion) is applied to the retardation layer in the circularly polarizing plate. There is a problem that the phase difference of the bent portion changes.

  Therefore, in order to solve such a problem, Patent Document 1 below includes a retardation film exhibiting predetermined optical characteristics, and the slow axis direction of the retardation film is 20 to 70 degrees with respect to the bending direction of the display device. Circular polarizers have been proposed that are adjusted to define the angle. In addition, using the resin films, such as a pure ace WR (polycarbonate resin film), as a phase difference film which shows a predetermined | prescribed optical characteristic to the following patent document 1 is disclosed.

  Moreover, in the following patent document 2, a retardation film including a half wavelength (λ / 2) plate and a quarter wavelength (λ / 4) plate is provided, and the λ / 2 plate and the λ / 4 plate are respectively liquid crystal. A circularly polarizing plate has been proposed which contains a compound and is adjusted so that the slow axis direction of the retardation film defines an angle of 75 to 105 degrees with respect to the bending direction of the display device.

JP, 2014-170221, A International Publication No. 2016/158300

  By the way, in the above-described bendable display device, further improvement in the visibility is required. In addition, it is required to reduce the change in the hue (color tone) of the reflected light at a bent portion when the display device is bent.

  On the other hand, in the present invention, the visibility of the display device is improved not only by reducing the change in hue before and after bending but also by designing a color that makes the change in hue inconspicuous before and after bending. I clarified that I could do it.

  That is, an object of the present invention is to provide a circularly polarizing plate capable of making a hue change inconspicuous before and after bending, and a bendable display device provided with such a circularly polarizing plate.

As means for solving the above problems, according to an aspect of the present invention, according to an aspect of the present invention, it is a circularly polarizing plate used for a bendable display device, and at least one polarizer and at least one polarizer disposed on one side of the polarizer. and a species more retardation layers, the hue of the reflected light obtained before and after bending, circular polarization, characterized in that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates A board is provided.

  In the circularly polarizing plate, the retardation layer may include a quarter wavelength plate.

  In the circularly polarizing plate, the retardation layer may include a half wave plate.

  In the circularly polarizing plate, the retardation layer may include a positive C plate.

  In the circularly polarizing plate, the retardation layer may include a layer in which a liquid crystal compound is cured.

  In the circularly polarizing plate, at least a part of the display device may be bent at a radius of curvature of 8 mm or less.

  In the circularly polarizing plate, the display may be an organic electroluminescent display.

  Further, according to an aspect of the present invention, there is provided a bendable display device including any one of the circularly polarizing plates and a bendable display panel.

  Further, in the display device, a touch sensor disposed on the side facing the display panel of the circularly polarizing plate, and a window film disposed on the opposite side to the side facing the display panel of the circularly polarizing plate May be provided.

  Further, the display device may be configured to include a touch sensor disposed on the side opposite to the side facing the display panel of the circularly polarizing plate.

  As described above, according to an aspect of the present invention, a circularly polarizing plate capable of making a hue change inconspicuous before and after bending, and a bendable display device provided with such a circularly polarizing plate are provided. It is possible.

It is sectional drawing which shows the structure of the circularly-polarizing plate which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the structure of the bendable display apparatus provided with the circularly-polarizing plate shown in FIG. It is sectional drawing which shows the structure of the circularly-polarizing plate which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the bendable display apparatus provided with the circularly-polarizing plate shown in FIG. It is sectional drawing which shows the structure of an organic EL element. It is a schematic diagram for demonstrating the bending state of a display apparatus. It is a schematic diagram for demonstrating the relationship between the bending direction of a display apparatus shown in FIG. 2, the absorption-axis direction of a polarizer, and the slow-axis direction of a 1st retardation film. Schematic diagram for explaining the relationship between the bending direction of the display device shown in FIG. 4 and the absorption axis direction of the polarizer, and the relationship between the slow axis direction of the λ / 2 plate and the slow axis direction of the λ / 4 plate It is. It is an a ^* b ^* chromaticity coordinate figure for demonstrating the hue change of the reflected light obtained before and behind bending of a circularly-polarizing plate. It is sectional drawing which shows another structural example of the bendable display apparatus provided with the circularly-polarizing plate of this invention. It is an a ^* b ^* chromaticity coordinate figure which shows the hue change before and behind bending about Examples 1-12 and Comparative Examples 1-3. It is an a ^* b ^* chromaticity coordinate figure which shows the hue change before and behind bending about Examples 13-20.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the drawings used in the following description, in order to make each component easy to see, the component may be schematically shown, and depending on the component, the scale of the dimensions may be different. In addition, the materials, numerical values, and the like exemplified in the following description are merely examples, and the present invention is not necessarily limited to them, and various modifications can be made without departing from the scope of the present invention. .

[Circularly polarizing plate]
First Embodiment
As a first embodiment of the present invention, for example, a bendable display device 10A provided with a circularly polarizing plate 1A shown in FIG. 1 and a circularly polarizing plate 1A shown in FIG. 2 will be described. FIG. 1 is a cross-sectional view showing the configuration of the circularly polarizing plate 1A. FIG. 2 is a cross-sectional view showing the configuration of a bendable display device 10A provided with a circularly polarizing plate 1A.

  As shown in FIG. 1, the circularly polarizing plate 1 </ b> A of the present embodiment includes a polarizer 2 and a first retardation film (first retardation layer) 3 </ b> A disposed on one side of the polarizer 2. And a second retardation film (second retardation layer) 4A. In addition, protective films (protective layers) 5 and 6 are disposed on both sides of the polarizer 2 respectively.

  The first retardation film 3A is laminated on one side of the polarizer 2 with the PSA layer (pressure-sensitive adhesive layer) 7 interposed therebetween. The first retardation film 3A and the second retardation film 4A are adhered via an adhesive layer or a pressure-sensitive adhesive layer 8. On the surface of the circularly polarizing plate 1A facing the second retardation film 4A, a PSA layer (pressure-sensitive adhesive layer) 9 for laminating on a display device 10A described later is disposed. A release film (not shown) is bonded to the surface of the PSA layer 9 until it is used. The PSA layers 7 and 9 are formed of, for example, an acrylic pressure-sensitive adhesive.

  The polarizer 2 transmits linearly polarized light having a polarization plane in a specific direction, and the light passing through the polarizer 2 becomes linearly polarized light vibrating in the transmission axis direction of the polarizer. The thickness of the polarizer 2 is, for example, about 1 μm to 80 μm.

  The polarizer 2 may be, for example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene / vinyl acetate copolymer-based partially saponified film, an iodine or a dichroic dye, or the like. In addition to those subjected to the dyeing process and the stretching process with a color substance, it is possible to use a polyene-based oriented film, such as a dehydrated product of polyvinyl alcohol, a dehydrochlorinated product of polyvinyl chloride, and the like. Among them, as a film excellent in optical properties, it is preferable to use a film obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it.

  Dyeing with iodine is performed, for example, by immersing a polyvinyl alcohol-based film in an aqueous iodine solution. It is preferable that the draw ratio of uniaxial stretching is 3 to 7 times. The stretching may be performed after the staining treatment, or may be performed while staining. Moreover, it may be dyed after being drawn.

  The polyvinyl alcohol-based film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, and the like, as necessary. For example, by immersing the polyvinyl alcohol-based film in water and washing with water prior to dyeing, it is possible not only to clean the stains and antiblocking agents on the surface of the polyvinyl alcohol-based film, but also to swell the polyvinyl alcohol-based film for dyeing Unevenness can be prevented.

  As the polarizer 2, for example, as described in JP-A-2016-170368, a cured film in which a liquid crystal compound is polymerized may be used in which a dichroic dye is oriented. As a dichroic dye, what has absorption in the range of wavelength 380-800 nm can be used, and it is preferable to use an organic dye. As a dichroic dye, an azo compound is mentioned, for example. The liquid crystal compound is a liquid crystal compound that can be polymerized while being oriented, and can have a polymerizable group in the molecule.

  The degree of visibility correction polarization of the polarizer 2 is preferably 95% or more, and more preferably 97% or more. Moreover, 99% or more may be sufficient and 99.9% or more may be sufficient. The degree of visibility correction polarization of the polarizer 2 may be 99.995% or less, or 99.99% or less. The luminosity correction polarization degree is measured by using a two-degree visual field (C light source) of “JIS Z 8701” with respect to the obtained polarization degree using an absorptiometer with integrating sphere (“V7100” manufactured by JASCO Corporation) It can be calculated by performing the visibility correction.

By setting the visibility correction polarization degree of the polarizer 2 to 95 to 99.9%, it is easy to adjust the initial hue (before bending) to a position away from neutral. Therefore, it relates hue of the reflected light before and after bending, which will be described later, the code is less likely to vary across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. Furthermore, the durability of the circularly polarizing plate 1 can be improved by setting the visibility correction polarization degree of the polarizer 2 to 99.9% or more. On the other hand, when the visibility correction polarization degree of the polarizer 2 is less than 95%, the function as an antireflective film may not be able to be achieved.

  The luminous transmittance correction single transmittance of the polarizer 2 is preferably 42% or more, more preferably 44% or more, preferably 60% or less, and still more preferably 50% or less. The visibility corrected single transmittance was measured using a spectrophotometer with integrating sphere (“V7100” manufactured by Nippon Bunko Co., Ltd.), and the obtained transmittance was viewed with a 2 degree visual field (C light source) of JIS Z 8701. It can be calculated by performing the correction.

  By setting the visibility correction orthogonal transmittance to 42% or more, the orthogonal hue of the polarizing plate can be easily adjusted to a position away from the neutral side, so that it is possible to make the color change inconspicuous before and after bending. If it exceeds 50%, the degree of polarization may be too low to achieve an antireflective function.

By setting the visibility correction single transmittance of the polarizer 2 to 42% or more, the orthogonal hue of the polarizer 2 can be easily adjusted to a position separated from the neutral side, so that the reflected light obtained before and after bending described later For the hue, it is easy to prevent the sign from changing across the a ^* coordinate axis and the b ^* coordinate axis in the a ^* b ^* chromaticity coordinates. On the other hand, if the luminous transmittance correction single transmittance of the polarizer 2 exceeds 50%, the degree of polarization becomes too low, and the function as the reflection prevention can not be achieved, which is not preferable.

  The first retardation film 3A can be a positive A plate functioning as a 1⁄4 wavelength (λ / 4) plate. The positive A plate has Nx> Ny, where Nx is the refractive index in the slow axis direction in the plane, Ny is the refractive index in the fast axis direction in the plane, and Nz is the refractive index in the thickness direction. Satisfy the relationship. The λ / 4 plate has a function of converting linearly polarized light of a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light).

  The first retardation film 3A exhibits any appropriate refractive index ellipsoid as long as the relationship of nx> ny is satisfied. Preferably, the refractive index ellipsoid of the first retardation film 3A has a relationship of Nx> Ny ≧ Nz (Nz represents the refractive index in the thickness direction). The Nz coefficient of the first retardation film 3A is preferably 1 to 2, more preferably 1 to 1.5, and still more preferably 1 to 1.3.

  The first retardation film 3A preferably exhibits reverse wavelength dispersion characteristics. Specifically, the in-plane retardation value Re (λ) at the wavelength λ [nm] has a relationship of Re (450) <Re (550) <Re (650), 100 nm ≦ Re (550) ≦ 200 nm. I am satisfied. By satisfying such a relationship, an excellent reflection hue can be achieved in the front direction of the display device 10A described later. It is preferable that Re (550) is in the range of 120 nm ≦ Re (550) ≦ 170 nm.

  The thickness of the first retardation film 3A is not particularly limited, but is preferably 0.5 to 10 μm, and more preferably 0.5 to 5 μm from the viewpoint of easily making the effect of preventing wrinkles at the time of bending remarkable. 0.5 to 3 μm is more preferable. In addition, about the thickness of 1st retardation film 3A, the thickness of arbitrary five points in a surface is measured, and those are arithmetically averaged.

  The first retardation film 3A can include a film made of a resin exemplified as a material of the protective films 5 and 6 described later, a layer in which a liquid crystal compound is cured, and the like. In the case of forming the first retardation film 3A from a resin, polycarbonate resins, cyclic olefin resins, styrene resins, and cellulose resins are particularly preferable. In the present embodiment, the first retardation film 3A preferably includes a layer in which the liquid crystal compound is cured. Although the type of liquid crystal compound is not particularly limited, it can be classified into a rod-like type (rod-like liquid crystal compound) and a disk-like type (disk-like liquid crystal compound, discotic liquid crystal compound) from the shape. Furthermore, there are low molecular type and high molecular type, respectively. The term “polymer” generally means one having a degree of polymerization of 100 or more (polymer physics / phase transition dynamics, Masao Doi, page 2, Iwanami Shoten, 1992).

  In the present embodiment, any liquid crystal compound can also be used. Furthermore, two or more types of rod-like liquid crystal compounds, two or more types of discotic liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a discotic liquid crystal compound may be used.

  As the rod-like liquid crystal compound, for example, those described in claim 1 of JP-A-11-513019 or in paragraphs [0026] to [0098] of JP-A-2005-289980 are preferably used. Can. As the discotic liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732 or paragraphs [0013]-[0108] of JP-A-2010-244038 are preferable. It can be used for

  The first retardation film 3A is more preferably formed using a liquid crystal compound (a rod-like liquid crystal compound or a discotic liquid crystal compound) having a polymerizable group. Thereby, temperature change and humidity change of optical characteristics can be reduced.

  The liquid crystal compound may be a mixture of two or more. In that case, it is preferable that at least one has two or more polymerizable groups. That is, the first retardation film 3A is preferably a layer formed by fixing a rod-like liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group by polymerization, and such a layer The liquid crystal compound is included in the cured layer. In this case, after forming a layer, it is no longer necessary to exhibit liquid crystallinity.

  The type of the polymerizable group contained in the rod-like liquid crystal compound or the discotic liquid crystal compound is not particularly limited, and, for example, a functional group capable of undergoing an addition polymerization reaction such as a polymerizable ethylenic unsaturated group or a ring polymerizable group. Is preferred. More specifically, for example, (meth) acryloyl group, vinyl group, styryl group, allyl group and the like can be mentioned. Among them, (meth) acryloyl group is preferable. In addition, a (meth) acryloyl group is the concept including both a methacryloyl group and an acryloyl group.

  The method for forming the first retardation film 3A is not particularly limited, and known methods may be mentioned. For example, a predetermined substrate (including a temporary substrate) is coated with a composition for forming an optically anisotropic layer (hereinafter, simply referred to as a “composition”) containing a liquid crystal compound having a polymerizable group to form a coating film. The first retardation film 3A can be manufactured by subjecting the obtained coating film to a curing treatment (irradiation with ultraviolet light (light irradiation treatment) or heat treatment).

  Application of the composition can be carried out by a known method, for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method.

  The composition may contain components other than the above-described liquid crystal compound. For example, the composition may contain a polymerization initiator. As the polymerization initiator to be used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of polymerization reaction. For example, examples of the photopolymerization initiator include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and combinations of triarylimidazole dimers and p-aminophenyl ketones. The use amount of the polymerization initiator is preferably 0.01 to 20% by mass, and more preferably 0.5 to 5% by mass with respect to the total solid content of the composition.

  The composition may also contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Among them, polyfunctional radically polymerizable monomers are preferred.

  The polymerizable monomer is preferably copolymerizable with the above-described liquid crystal compound containing a polymerizable group. Examples of specific polymerizable monomers include those described in paragraphs [0018] to [0020] in JP-A-2002-296423. The use amount of the polymerizable monomer is preferably 1 to 50% by mass, and more preferably 2 to 30% by mass with respect to the total mass of the liquid crystal compound.

  The composition may also contain a surfactant in terms of the uniformity of the coating film and the strength of the film. As surfactant, a conventionally well-known compound is mentioned. Among them, fluorine compounds are particularly preferable. Specific examples of the surfactant include compounds described in paragraphs [0028] to [0056] in JP-A-2001-330725, and paragraphs [0069] to [0126] in Japanese Patent Application No. 2003-295212. The compound as described in can be mentioned.

  The composition may contain a solvent, and an organic solvent is preferably used. As the organic solvent, for example, amide (eg, N, N-dimethylformamide), sulfoxide (eg, dimethyl sulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide (eg, Chloroform, dichloromethane), esters (eg, methyl acetate, ethyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Among them, alkyl halides and ketones are preferable. Also, two or more organic solvents may be used in combination.

  Further, the composition includes a vertical alignment promoter such as a polarizer interface side vertical alignment agent, an air interface side vertical alignment agent, and a horizontal alignment promoter such as a polarizer interface side horizontal alignment agent and an air interface horizontal alignment agent. And various alignment agents may be included. In addition to the above components, the composition may further contain an adhesion improver, a plasticizer, a polymer and the like.

  The first retardation film 3A may include an alignment film having a function of defining the alignment direction of the liquid crystal compound. The alignment film generally contains a polymer as a main component. A polymer material for alignment film is described in many documents, and many commercially available products are available. Among them, it is preferable to use polyvinyl alcohol or polyimide or a derivative thereof as the polymer material, and it is particularly preferable to use modified or unmodified polyvinyl alcohol.

  About the alignment film which can be used in this embodiment, the modification as described in page 43 line 24-page 49 line 8 of WO 2001/88574, and paragraph [0071]-[0095] of patent 3907735 is mentioned. Reference can be made to polyvinyl alcohol.

  The alignment film is usually subjected to known alignment treatment. For example, rubbing treatment, photoalignment treatment for applying polarized light, etc. may be mentioned, but from the viewpoint of the surface roughness of the alignment film, photoalignment treatment is preferable.

  Although the thickness of the alignment film is not particularly limited, it is often 20 μm or less in many cases, among which 0.01 to 10 μm is preferable, 0.01 to 5 μm is more preferable, and 0.01 to 5 μm is more preferable. More preferably, it is 1 μm.

  The second retardation film 4A can function as a positive C plate. The positive C plate satisfies the relationship Nz> Nx ≧ Ny. By including the positive C plate, it is possible to reduce the change in the hue (color tone) of the reflected light at the bent portion when the display device 10A described later is bent. The difference between the values of Nx and Ny is preferably within 0.5% of the value of Ny, and more preferably within 0.3%. If it is within 0.5%, it can be regarded substantially as Nx = Ny.

  The second retardation film 4A preferably has a retardation value Rth (λ) in the thickness direction at a wavelength λ [nm] of which satisfies the relationship −300 nm ≦ Rth (550) ≦ −20 nm, −150 nm ≦ It is more preferable to satisfy the relationship of Rth (550) ≦ −20 nm.

  Although the thickness of the second retardation film 4A is not particularly limited, it is preferably 0.5 to 10 μm, and more preferably 0.5 to 5 μm from the viewpoint of preventing wrinkles due to a difference in dimensional change on the front and back of the film at the time of bending. Preferably, 0.5 to 3 μm is more preferable. In addition, about the thickness of 2nd retardation film 4A, the thickness of arbitrary five points in a surface is measured, and those are arithmetically averaged.

  The second retardation film 4A preferably includes a layer in which the liquid crystal compound is cured. The kind of liquid crystal compound is not particularly limited, but the same material as the material of the first retardation film 3A can be used. Among them, a layer formed by fixing a rod-like liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group by polymerization is preferable. In this case, after forming a layer, it is no longer necessary to exhibit liquid crystallinity.

  Of the layers contained in the circularly polarizing plate 1A, it is preferable to use one or two layers other than the polarizer 2 in which the liquid crystal compound is cured. When the retardation film is a layer in which the liquid crystal compound is cured, the thickness can be reduced, so that the dimensional change of the retardation layer when bent with the same diameter can be reduced as compared with the use of a thick film type. It is preferable because the change in phase difference can be suppressed.

  The first retardation film 3A and the second retardation film 4A are not necessarily limited to the configuration including the layer in which the liquid crystal compound described above is cured, and for example, a film made of a thermoplastic resin is stretched. It is also possible to use the first retardation film 3A and the second retardation film 4A to which the above-described retardation value is given by performing uniaxial stretching or biaxial stretching or the like.

  The protective films 5 and 6 function as a protective layer for protecting the polarizer 2 and at least on the outer surface of the polarizer 2 (the surface opposite to the side facing the first retardation film 3A) A protective film 5 is disposed. In addition, the protective film 6 may be disposed on the inner surface of the polarizer 2 (the surface on the side facing the first retardation film 3A).

  The material of the protective films 5 and 6 is, for example, a translucent (preferably optically transparent) thermoplastic resin, for example, a chain-like polyolefin resin (polypropylene resin etc.), cyclic polyolefin resin (norbornene) Resins, etc.), cellulose triacetate, cellulose ester resins such as cellulose diacetate, polyester resins, polycarbonate resins, (meth) acrylic resins, polystyrene resins, or mixtures thereof A polymer etc. can be used. That is, the first retardation film 3A can also serve as the protective films 5 and 6.

  The protective films 5 and 6 may be protective films having an optical function such as a retardation film or a brightness enhancement film. For example, a retardation film to which an arbitrary retardation value is imparted by stretching (such as uniaxial stretching or biaxial stretching) a film made of the above-mentioned thermoplastic resin, or forming a liquid crystal layer or the like on the film. It can be done.

  Examples of linear polyolefin resins include homopolymers of linear olefins such as polyethylene resins and polypropylene resins, and copolymers of two or more linear olefins.

  Cyclic polyolefin resin is a general term for resin polymerized as cyclic olefin as a polymerization unit. Specific examples of cyclic polyolefin resins include, for example, ring-opened (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and linear olefins such as ethylene and propylene (representatively, And copolymers thereof, and graft polymers obtained by modifying these with unsaturated carboxylic acids and derivatives thereof, and hydrides thereof. Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers as cyclic olefins are preferably used.

  The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester-based resin include, for example, cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Moreover, these copolymers, and those in which a part of the hydroxyl groups are modified with other substituents can also be used. Among them, cellulose triacetate (triacetyl cellulose: TAC) is particularly preferable.

  The polyester-based resin is a resin having an ester bond and other than the above-mentioned cellulose ester-based resin, and is generally made of a polycondensate of polyvalent carboxylic acid or derivative thereof and polyvalent alcohol. As polyvalent carboxylic acid or its derivative, dicarboxylic acid or its derivative can be used, For example, a terephthalic acid, an isophthalic acid, a dimethyl terephthalate, dimethyl naphthalene dicarboxylic acid etc. are mentioned. As a polyhydric alcohol, a diol can be used, for example, ethylene glycol, propanediol, butanediol, neopentyl glycol, cyclohexane dimethanol and the like.

  Specific examples of the polyester resin include, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethyl naphthalate. It can be mentioned.

  Polycarbonate resins consist of polymers in which monomer units are linked via a carbonate group. The polycarbonate-based resin may be a resin called a modified polycarbonate in which the polymer skeleton is modified, a copolycarbonate, or the like.

The (meth) acrylic resin is a resin having a compound having a (meth) acryloyl group as a main constituent monomer. Specific examples of (meth) acrylic resins include, for example, poly (meth) acrylic acid esters such as poly (methyl methacrylate), methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid Acid ester copolymer, methyl methacrylate-acrylic acid ester-(meth) acrylic acid copolymer, methyl (meth) acrylate-styrene copolymer (MS resin etc.), methyl methacrylate and alicyclic hydrocarbon group And copolymers thereof (e.g., methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth) acrylate copolymer, etc.). Preferably, the polymer mainly composed of poly (meth) acrylic acid C _1-6 alkyl esters, such as poly (meth) acrylate is used. More preferably, a methyl methacrylate resin having methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

  The thickness of the protective films 5 and 6 is preferably 10 μm to 200 μm, more preferably 10 μm to 100 μm, and still more preferably 15 μm to 95 μm. The protective films 5 and 6 have in-plane retardation value Re (550) of, for example, 0 nm to 10 nm, and retardation value Rth (550) of thickness direction of, for example, -80 nm to +80 nm.

  The outer protective film 5 is subjected to surface treatment such as hard coating treatment, anti-reflection treatment, anti-sticking treatment, anti-glare treatment, and the like on the surface opposite to the side facing the polarizer 2 as necessary. May be The thickness of the protective film 5 in this case is 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, and still more preferably 5 μm to 150 μm.

  The inner protective film 6 is preferably optically isotropic. That is, the phrase "optically isotropic" means that the in-plane retardation value Re (550) is 0 nm to 10 nm, and the retardation value Rth (550) in the thickness direction is -10 nm to +10 nm. Say The thickness of the protective film 6 in this case is preferably 20 μm to 200 μm, more preferably 30 μm to 100 μm, and still more preferably 35 μm to 95 μm.

  The adhesive layer 8 is, for example, an active energy ray-curable adhesive (preferably ultraviolet ray) containing a curable compound which is cured by irradiation of active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays as an adhesive. A curable adhesive) or a water-based adhesive in which an adhesive component such as a polyvinyl alcohol resin is dissolved or dispersed in water can be used. In the circularly polarizing plate 1A, by laminating the first retardation film 3A and the second retardation film 4A via the adhesive layer 8, it is possible to prevent the formation of wrinkles during bending. In addition, in the case where the λ / 2 plate 3B and the λ / 4 plate 4B are laminated via the adhesive layer 8 in the circularly polarizing plate 1B described later, it is also possible to prevent the formation of wrinkles during bending.

  As an active energy ray-curable adhesive, an active energy ray-curable adhesive composition containing a cationically polymerizable curable compound and / or a radically polymerizable curable compound is preferably used because it exhibits good adhesion. be able to. The active energy ray-curable adhesive can further include a cationic polymerization initiator and / or a radical polymerization initiator for initiating a curing reaction of the above-mentioned curable compound.

  As the cationically polymerizable curable compound, for example, an epoxy compound (a compound having one or more epoxy groups in the molecule) or an oxetane compound (one or more oxetane rings in the molecule) And compounds thereof, or combinations thereof. Examples of the radically polymerizable curable compound include (meth) acrylic compounds (compounds having one or more (meth) acryloyloxy groups in the molecule) and radically polymerizable double bonds. Other vinyl compounds or combinations thereof can be mentioned. The cationically polymerizable curable compound and the radically polymerizable curable compound may be used in combination.

  The active energy ray-curable adhesive may, if necessary, be a cationic polymerization accelerator, an ion trap agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow control agent, a plasticizer, a plasticizer. Additives such as a foaming agent, an antistatic agent, a leveling agent, and a solvent can be contained.

  When bonding retardation film 3A, 4A using an active energy ray hardening adhesive, it laminates retardation film 3A and retardation film 4A via the active energy ray hardening adhesive used as adhesive agent layer 8 After that, the adhesive layer is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams and X-rays. Among them, ultraviolet light is preferable, and as a light source in this case, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp and the like can be used. In the case of using a water-based adhesive, after the retardation film 3A and the retardation film 4A are laminated via the water-based adhesive, it may be heated and dried.

  0.5-5 micrometers is preferable and, as for the thickness of the adhesive bond layer 8, 0.5-3 micrometers is more preferable.

  The storage elastic modulus at a temperature of 30 ° C. of the adhesive layer 8 is preferably 600 MPa to 4000 MPa, more preferably 700 MPa to 3500 MPa, still more preferably 1000 MPa to 3000 MPa, and 1500 MPa to 3000 MPa. Is most preferred. By bonding the retardation films 3A and 4A to each other with the hard adhesive layer 8 exhibiting such storage elastic modulus, it is possible to further prevent generation of wrinkles in the retardation layer at the time of bending.

  The storage elastic modulus at a temperature of 30 ° C. of the adhesive layer 8 is a measured value when the storage elastic modulus at a temperature of 30 ° C. of the adhesive layer 8 in the circularly polarizing plate 1 can be directly measured by the following method. On the other hand, when the measurement can not be made directly, an adhesive layer test piece was formed on the release paper under the same conditions (type of adhesive, curing conditions) as the formation of the adhesive layer 8, and the adhesive layer test piece was peeled off from the release paper. It can be regarded as the same value as the storage elastic modulus measured by the following method.

  The storage elastic modulus of the adhesive layer 8 or the adhesive layer test piece can be measured by a commercially available dynamic viscoelasticity device, for example, it can be measured by the product name DVA-220 manufactured by IT Measurement & Control Co., Ltd. .

  The pressure-sensitive adhesive layer 8 may be appropriately selected from conventionally known pressure-sensitive adhesives, and peeling does not occur in a high-temperature environment to which the polarizing plate is exposed, a wet heat environment, or an environment where high and low temperatures are repeated. What is necessary is to have a certain degree of adhesiveness. Specifically, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives and the like can be mentioned, and acrylic pressure-sensitive adhesives are particularly preferable in terms of transparency, weather resistance, heat resistance and processability.

  The adhesive may be, if necessary, a tackifier, a plasticizer, a glass fiber, a glass bead, a filler made of metal powder, other inorganic powder, a pigment, a colorant, a filler, an antioxidant, an ultraviolet absorber, and the like. Various additives such as an antistatic agent and a silane coupling agent may be appropriately blended.

  The pressure-sensitive adhesive layer 8 is usually formed by applying a pressure-sensitive adhesive solution on a release sheet and drying it. For example, roll coating such as reverse coating or gravure coating, spin coating, screen coating, fountain coating, dipping, spraying, etc. may be employed for application on the release sheet. The release sheet provided with the pressure-sensitive adhesive layer is utilized by a method of transferring the same.

  The thickness of the pressure-sensitive adhesive layer 8 is usually about 3 to 100 μm, preferably 5 to 50 μm.

Second Embodiment
As a second embodiment of the present invention, a bendable display device 10B provided with, for example, a circularly polarizing plate 1B shown in FIG. 3 and a circularly polarizing plate 1B shown in FIG. 4 will be described. FIG. 3 is a cross-sectional view showing the configuration of the circularly polarizing plate 1B. FIG. 4 is a cross-sectional view showing the configuration of a bendable display device 10B provided with a circularly polarizing plate 1B. Moreover, in the following description, while abbreviate | omitting description about the site | part equivalent to the said circularly-polarizing plate 1A, suppose that the same code | symbol is attached | subjected in drawing.

  As shown in FIG. 3, the circularly polarizing plate 1 </ b> B according to the present embodiment includes a polarizer 2 and a half wavelength (λ / 2) plate 3 </ b> B disposed on one side of the polarizer 2 and a quarter wavelength. And a retardation layer RF including the (λ / 4) plate 4B. In addition, protective films (protective layers) 5 and 6 are disposed on both sides of the polarizer 2 respectively.

  The λ / 2 plate 3B is laminated on one side of the polarizer 2 with the PSA layer (pressure-sensitive adhesive layer) 7 interposed therebetween. The λ / 2 plate 3B and the λ / 4 plate 4B are laminated via an adhesive layer or a pressure-sensitive adhesive layer 8. On a surface of the circularly polarizing plate 1 facing the λ / 4 plate 4B, a PSA layer (pressure-sensitive adhesive layer) 9 for laminating on a display device 10B described later is disposed. A release film (not shown) is bonded to the surface of the PSA layer 9 until it is used. The PSA layers 7 and 9 are formed of, for example, an acrylic pressure-sensitive adhesive.

  The λ / 2 plate 3B gives a phase difference of π (= λ / 2) to the electric field vibration direction (polarization plane) of incident light, and has a function of changing the direction (polarization direction) of linear polarization. . In addition, when circularly polarized light is made incident, the rotational direction of circularly polarized light can be reversed.

  The λ / 2 plate 3B has an in-plane retardation value Re (λ) at a specific wavelength λ nm that satisfies Re (λ) = λ / 2. This equation may be achieved at any wavelength in the visible light range (eg, 550 nm). Among them, it is preferable that Re (550) which is an in-plane retardation value at a wavelength of 550 nm satisfies 210 nm ≦ Re (550) ≦ 300 nm. More preferably, 220 nm ≦ Re (550) ≦ 290 nm is satisfied.

  The retardation value Rth (550), which is the retardation value in the thickness direction of the λ / 2 plate 3B measured at a wavelength of 550 nm, is preferably −150 to 150 nm, and more preferably −100 to 100 nm.

  The thickness of the λ / 2 plate 3B is not particularly limited, but is preferably 0.5 to 10 μm, more preferably 0.5 to 5 μm, and more preferably 0.5 to 3 μm from the viewpoint of easily making the effect of preventing wrinkles remarkable. Is more preferred. In addition, about the thickness of (lambda) / 2 board 3B, the thickness of arbitrary five points in a surface is measured, and those are arithmetically averaged. In the case of the resin film conventionally used, wrinkles are unlikely to occur in the first place.

  The λ / 2 plate 3B preferably includes a layer in which the liquid crystal compound is cured. Although the type of liquid crystal compound is not particularly limited, it can be classified into a rod-like type (rod-like liquid crystal compound) and a disk-like type (disk-like liquid crystal compound, discotic liquid crystal compound) from the shape. Furthermore, there are low molecular type and high molecular type, respectively. The term “polymer” generally means one having a degree of polymerization of 100 or more (polymer physics / phase transition dynamics, Masao Doi, page 2, Iwanami Shoten, 1992).

  In the present embodiment, any liquid crystal compound can also be used. Furthermore, two or more types of rod-like liquid crystal compounds, two or more types of discotic liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a discotic liquid crystal compound may be used.

  As the rod-like liquid crystal compound, for example, those described in claim 1 of JP-A-11-513019 or in paragraphs [0026] to [0098] of JP-A-2005-289980 are preferably used. Can. As the discotic liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732 or paragraphs [0013]-[0108] of JP-A-2010-244038 are preferable. It can be used for

  The λ / 2 plate 3B is more preferably formed using a liquid crystal compound (a rod-like liquid crystal compound or a disc-like liquid crystal compound) having a polymerizable group. Thereby, temperature change and humidity change of optical characteristics can be reduced.

  The liquid crystal compound may be a mixture of two or more. In that case, it is preferable that at least one has two or more polymerizable groups. That is, the λ / 2 plate 3B is preferably a layer formed by fixing a rod-like liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group by polymerization. In this case, after forming a layer, it is no longer necessary to exhibit liquid crystallinity.

  The type of the polymerizable group contained in the rod-like liquid crystal compound or the discotic liquid crystal compound is not particularly limited, and, for example, a functional group capable of undergoing an addition polymerization reaction such as a polymerizable ethylenic unsaturated group or a ring polymerizable group. Is preferred. More specifically, for example, (meth) acryloyl group, vinyl group, styryl group, allyl group and the like can be mentioned. Among them, (meth) acryloyl group is preferable. In addition, a (meth) acryloyl group is the concept including both a methacryloyl group and an acryloyl group.

  The method of forming the λ / 2 plate 3B is not particularly limited, and a known method may be mentioned. For example, a predetermined substrate (including a temporary substrate) is coated with a composition for forming an optically anisotropic layer (hereinafter, simply referred to as a “composition”) containing a liquid crystal compound having a polymerizable group to form a coating film. The first? / 2 plate 3B can be manufactured by subjecting the obtained coating film to a curing treatment (irradiation with ultraviolet light (light irradiation treatment) or heat treatment).

  Application of the composition can be carried out by a known method, for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method.

  The composition may contain components other than the above-described liquid crystal compound. For example, the composition may contain a polymerization initiator. As the polymerization initiator to be used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of polymerization reaction. For example, examples of the photopolymerization initiator include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and combinations of triarylimidazole dimers and p-aminophenyl ketones. The use amount of the polymerization initiator is preferably 0.01 to 20% by mass, and more preferably 0.5 to 5% by mass with respect to the total solid content of the composition.

  The composition may also contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Among them, polyfunctional radically polymerizable monomers are preferred.

  The polymerizable monomer is preferably copolymerizable with the above-described liquid crystal compound containing a polymerizable group. Examples of specific polymerizable monomers include those described in paragraphs [0018] to [0020] in JP-A-2002-296423. The use amount of the polymerizable monomer is preferably 1 to 50% by mass, and more preferably 2 to 30% by mass with respect to the total mass of the liquid crystal compound.

  The composition may also contain a surfactant in terms of the uniformity of the coating film and the strength of the film. As surfactant, a conventionally well-known compound is mentioned. Among them, fluorine compounds are particularly preferable. Specific examples of the surfactant include compounds described in paragraphs [0028] to [0056] in JP-A-2001-330725, and paragraphs [0069] to [0126] in Japanese Patent Application No. 2003-295212. The compound as described in can be mentioned.

  The composition may contain a solvent, and an organic solvent is preferably used. As the organic solvent, for example, amide (eg, N, N-dimethylformamide), sulfoxide (eg, dimethyl sulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide (eg, Chloroform, dichloromethane), esters (eg, methyl acetate, ethyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Among them, alkyl halides and ketones are preferable. Also, two or more organic solvents may be used in combination.

  Further, the composition includes a vertical alignment promoter such as a polarizer interface side vertical alignment agent, an air interface side vertical alignment agent, and a horizontal alignment promoter such as a polarizer interface side horizontal alignment agent and an air interface horizontal alignment agent. And various alignment agents may be included. In addition to the above components, the composition may further contain an adhesion improver, a plasticizer, a polymer and the like.

  The λ / 2 plate 3B may include an alignment film having a function of defining the alignment direction of the liquid crystal compound. The alignment film generally contains a polymer as a main component. A polymer material for alignment film is described in many documents, and many commercially available products are available. Among them, it is preferable to use polyvinyl alcohol or polyimide or a derivative thereof as the polymer material, and it is particularly preferable to use modified or unmodified polyvinyl alcohol.

  About the alignment film which can be used in this embodiment, the modification as described in page 43 line 24-page 49 line 8 of WO 2001/88574, and paragraph [0071]-[0095] of patent 3907735 is mentioned. Reference can be made to polyvinyl alcohol.

  The alignment film is usually subjected to known alignment treatment. For example, rubbing treatment, photoalignment treatment for applying polarized light, etc. may be mentioned, but from the viewpoint of the surface roughness of the alignment film, photoalignment treatment is preferable.

  Although the thickness of the alignment film is not particularly limited, it is often 20 μm or less in many cases, among which 0.01 to 10 μm is preferable, 0.01 to 5 μm is more preferable, and 0.01 to 5 μm is more preferable. More preferably, it is 1 μm.

  The λ / 4 plate 4B gives a phase difference of π / 2 (= λ / 4) to the electric field vibration direction (polarization plane) of incident light, and converts linearly polarized light of a specific wavelength into circularly polarized light (or a circle It has a function of converting polarized light into linearly polarized light.

  In the λ / 4 plate 4B, Re (λ) which is an in-plane retardation value at a specific wavelength λ nm satisfies Re (λ) = λ / 4. This equation may be achieved at any wavelength in the visible light range (eg, 550 nm). Among them, it is preferable that Re (550) which is an in-plane retardation value at a wavelength of 550 nm satisfies 100 nm ≦ Re (550) ≦ 160 nm. Furthermore, it is more preferable to satisfy 110 nm ≦ Re (550) ≦ 150 nm.

  The retardation value Rth (550), which is the retardation value in the thickness direction of the λ / 4 plate 4B measured at a wavelength of 550 nm, is preferably −120 to 120 nm, and more preferably −80 to 80 nm.

  The thickness of the λ / 4 plate 4B is not particularly limited, but is preferably 0.5 to 10 μm, and more preferably 0.5 to 5 μm from the viewpoint of preventing wrinkles due to a difference in dimensional change on the front and back of the film during bending. 0.5 to 3 μm is more preferable. In addition, about the thickness of (lambda) / 4 board 4B, the thickness of arbitrary five points in a surface is measured, and those are arithmetically averaged.

  The λ / 4 plate 4B preferably includes a layer in which the liquid crystal compound is cured. The kind of liquid crystal compound is not particularly limited, but the same material as the material of the λ / 2 plate 3B can be used. Among them, a layer formed by fixing a rod-like liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group by polymerization is preferable. In this case, after forming a layer, it is no longer necessary to exhibit liquid crystallinity.

  Of the layers contained in the circularly polarizing plate 1B, it is preferable to use one or two layers other than the polarizer 2 in which the liquid crystal compound is cured. When three or more layers in which the liquid crystal compound is cured are included, it is considered that wrinkles are likely to occur during bending because the number of layers in which wrinkles may occur is increased.

  In addition, about (lambda) / 2 board 3B and (lambda) / 4 board 4B, it is not necessarily limited to the structure containing the layer which the liquid crystal compound hardened | cured above mentioned, for example, stretches the film which consists of thermoplastic resins (uniaxial stretching or It is also possible to use the 1st phase difference film 3A and the 2nd phase difference film 4A to which the phase difference value mentioned above was given by carrying out biaxial stretching etc.).

  The protective films 5, 6 function as a protective layer for protecting the polarizer 2, and at least on the outer surface of the polarizer 2 (the surface opposite to the side facing the λ / 2 plate 3B). 5 are arranged. In addition, the protective film 6 may be disposed on the inner surface of the polarizer 2 (the surface on the side facing the λ / 2 plate 3B).

[Display device]
The circularly polarizing plates 1A and 1B of the present embodiment are used in bendable display devices 10A and 10B as shown in FIGS. 2 and 4. Specific examples of the bendable display devices 10A and 10B include an organic EL display device, a liquid crystal display device using circularly polarized light (typically, a liquid crystal display device of VA (Vertical Alignment) mode), MEMS (Micro Electro Mechanical) Systems) displays and the like. Among them, in particular, the circularly polarizing plates 1A and 1B of the present embodiment are suitably used for a bendable organic EL display device.

  Specifically, as shown in FIGS. 2 and 4, in the display devices 10A and 10B of the present embodiment, the circularly polarizing plates 1A and 1B disposed on the bendable display panel 20 and the viewing side of the display panel 20. And have. In the display device 10A shown in FIG. 2, in the circularly polarizing plate 1A, the polarizer 2 is on the viewing side, and the second retardation film 4A is on the display panel 20 side. It is stuck on the viewing side. On the other hand, in the display device 10B shown in FIG. 4, in the circularly polarizing plate 1B, the display panel 20 is viewed through the PSA layer 9 so that the polarizer 2 is on the viewing side and the retardation layer RF is on the display panel 20 side. It is stuck on the side surface.

  In the display device 10A according to the first embodiment, when external light is incident from the viewing side of the display panel 20, light passing through the polarizer 2 becomes linearly polarized light. In this linearly polarized light, the light passing through the first retardation film 3A and the second retardation film 4A, which are λ / 4 plates, is circularly polarized. The circularly polarized light is reflected by the display panel 20 to become circularly polarized light which is inverted from that at the time of incidence. When the circularly polarized light reflected by the display panel 20 passes through the first retardation film 3A and the second retardation film 4A, which become λ / 4 plates again, it is linearly polarized light orthogonal to the time of incidence. Become. Therefore, this linearly polarized light is blocked by the polarizer 2. As a result, it is possible to suppress the influence of external light reflection.

  On the other hand, in the display device 10B according to the second embodiment, external light enters from the viewing side of the display panel 20, whereby the light passing through the polarizer 2 becomes linearly polarized light. The linearly polarized light passes through the λ / 2 plate 3B to change the direction of the linearly polarized light, and then passes through the λ / 4 plate 4B to become circularly polarized light. The circularly polarized light is reflected by the display panel 20 to become circularly polarized light which is inverted from that at the time of incidence. When the circularly polarized light reflected by the display panel 20 passes through the λ / 4 plate 4B and the λ / 2 plate 3B again, it becomes linearly polarized light orthogonal to the time of incidence. Therefore, this linearly polarized light is blocked by the polarizer 2. As a result, it is possible to suppress the influence of external light reflection.

[Organic EL element]
An example of the display panel 20 includes an organic EL element 200 as shown in FIG. 5, for example. FIG. 5 is a cross-sectional view showing the configuration of the organic EL element 200. As shown in FIG.

  Specifically, the organic EL element 200 includes a substrate 210, a first electrode 220, an organic EL layer 230, a second electrode 240, and a sealing layer 250 covering them. In addition, in the organic EL element 200, for example, a planarization layer (not shown) may be provided on the substrate 210 as needed, and a short circuit is prevented between the first electrode 220 and the second electrode 240. An insulating layer (not shown) may be provided.

  The substrate 210 is made of a flexible material. By using the flexible substrate 210, the display devices 10A and 10B can be bent at the above-described radius of curvature. In addition, since the organic EL element 200 can be manufactured by a so-called roll-to-roll process, low cost and mass production can be realized. Further, the substrate 210 is preferably made of a material having a barrier property. Such a substrate 210 can protect the organic EL layer 230 from oxygen and moisture.

  Specific materials of the substrate 210 having barrier properties and flexibility include, for example, thin glass to which flexibility is imparted, thermoplastic resin or thermosetting resin film to which barrier properties are imparted, alloys, metals and the like. Be

  As a thermoplastic resin or thermosetting resin, for example, polyester resin, polyimide resin, epoxy resin, polyurethane resin, polystyrene resin, polyolefin resin, polyamide resin, polycarbonate resin, silicone resin, fluorine resin Examples include resin based resins, acrylonitrile-butadiene-styrene copolymer resins. Examples of the alloy include stainless steel, 36 alloy and 42 alloy. Examples of the metal include copper, nickel, iron, aluminum and titanium.

  The thickness of the substrate 210 is preferably 5 μm to 500 μm, more preferably 5 μm to 300 μm, and still more preferably 10 μm to 200 μm. With such a thickness, the display devices 10A and 10B can be bent at the above-described radius of curvature. Moreover, the organic EL element 200 can be used suitably for a roll to roll process.

  The first electrode 220 can function as an anode. In this case, a material having a large work function is preferable as the material constituting the first electrode from the viewpoint of facilitating the hole injection property. Specific examples of such materials include indium tin oxide (ITO), indium zinc oxide (IZO), indium tin oxide added with silicon oxide (ITSO), indium oxide containing tungsten oxide (IWO), Transparent conductive materials such as indium zinc oxide (IWZO) containing tungsten oxide, indium oxide (ITO) containing titanium oxide, indium tin oxide (ITTiO) containing titanium oxide, indium tin oxide (ITMO) containing molybutene And metals such as gold, silver, platinum and their alloys.

  The organic EL layer 230 is a laminate including various organic thin films. Specifically, the organic EL layer 230 is made of a hole injecting organic material (for example, a triphenylamine derivative) and provided with a hole injecting layer 230a provided to improve the hole injecting efficiency from the anode, for example, A hole transporting layer 230b made of copper phthalocyanine and a light emitting organic material (eg, anthracene, bis [N- (1-naphthyl) -N-phenyl] benzidine, N, N′-diphenyl-NN-bis (1 Light-emitting layer 230c made of -naphthyl) -1,1 '-(biphenyl) -4,4'-diamine (NPB), an electron transporting layer 230d made of, for example, 8-quinolinol aluminum complex, and an electron injecting material (for example, And an electron injection layer 230 e provided to improve the electron injection efficiency from the cathode.

  As the organic EL layer 230, any appropriate combination that can recombine electrons and holes in the light emitting layer 230c to cause light emission is adopted. The thickness of the organic EL layer 230 is preferably as thin as possible in order to transmit emitted light as much as possible, specifically, 5 nm to 200 nm, and more preferably about 10 nm.

  The second electrode 240 can function as a cathode. In this case, as a material forming the second electrode 240, a material having a small work function is preferable from the viewpoint of facilitating electron injection to increase the light emission efficiency. Specific examples of such materials include aluminum, magnesium, and their alloys.

  The sealing layer 250 is made of a material having excellent barrier properties and transparency. As a material which comprises the sealing layer 250, an epoxy resin, polyurea, etc. are mentioned, for example. Alternatively, the sealing layer 250 may be formed by applying an epoxy resin (epoxy resin adhesive) and adhering a barrier sheet thereon.

  The organic EL element 200 can be manufactured continuously by a roll-to-roll process. The organic EL element 200 can be manufactured by the procedure according to the procedure described, for example in the 2012-169236 gazette. The description of the publication is incorporated herein by reference. Furthermore, the organic EL element 200 may be continuously laminated with the long circular polarizers 1A and 1B in a roll-to-roll process, so that the organic EL display may be manufactured continuously.

  The details of the bendable organic EL display device are described, for example, in Japanese Patent No. 4601463 or Japanese Patent No. 4707996. These descriptions are incorporated herein by reference.

  Although the display panel 20 exemplifies the aspect using the organic EL element 200, the present invention is not necessarily limited to such an aspect, and the display devices 10A and 10B to which the present invention is applied are, for example, The aspect provided with the display panel 20 which consists of a liquid crystal display element, and circularly-polarizing plate 1A, 1B arrange | positioned at the visual recognition side of the display panel 20 may be sufficient.

[Bending direction of display device]
As shown in FIG. 6A to FIG. 6D, the display devices 10A and 10B of the present embodiment also include a bent state (a state where the bend is fixed). 6 (a) to 6 (d) are schematic views for explaining the bending state of the display devices 10A and 10B.

  Specifically, the display devices 10A and 10B may be bent at the central portion, for example, in a foldable manner as shown in FIGS. 6 (a) and 6 (b). In addition, from the viewpoint of securing the design property and the display screen as maximum, as shown in FIG. 6C and FIG. 6D, the end may be bent.

  Furthermore, as shown in FIGS. 6A to 6D, the display devices 10A and 10B may be bent along the longitudinal direction, and even if the display devices 10A and 10B are bent along the lateral direction. Good. That is, in the display devices 10A and 10B, specific portions may be bent (for example, some or all of the four corners in an oblique direction) according to the application.

  The radius of curvature (flexure radius) of at least a part of the display devices 10A and 10B is preferably 10 mm or less, more preferably 8 mm or less, and still more preferably 4 mm or less. In the display devices 10A and 10B of the present embodiment, changes in the hue (color tone) of the reflected light in a state of being bent with such a very small radius of curvature are reduced, and wrinkles are less likely to occur in the circularly polarizing plate 1.

  The relationship between the bending direction (the direction orthogonal to the bending start line L) of the display device 10A and the absorption axis direction of the polarizer 2 and the slow axis direction of the first retardation film 3A is shown in FIGS. 7A and 7B. Explain with reference to. FIGS. 7A and 7B are schematic diagrams for explaining the relationship between the bending direction of the display device 10A and the absorption axis direction of the polarizer 2 and the slow axis direction of the first retardation film 3A. It is. 7 (a) and 7 (b), the absorption axis direction of the polarizer 2 is shown by "solid line", and the slow axis direction of the first retardation film 3A is shown by "broken line".

  As shown in FIGS. 7A and 7B, the display device 10A has at least the flat portion 10a and the linear bending start line L located at the end of the flat portion 10a (FIGS. 7A and 7B). And a bent portion 10b which is bent along a direction (bending direction) orthogonal to the bending start line L). In this case, the bending direction of the display device 10A is a straight bending start line L when the display device 10A is viewed from the normal direction of the flat portion 10a (the Z-axis direction in FIGS. 7A and 7B). It corresponds to the direction (the Y-axis direction in FIGS. 7A and 7B) orthogonal to the above.

  In the display device 10A of the present embodiment, the bending direction of the display device 10A with respect to the absorption axis direction (0 °) of the polarizer 2 is −5 ° to 5 ° or 85 ° to 95 ° with counterclockwise rotation being positive. It is set to a range, more preferably 0 ° (see FIG. 7 (a)) or 90 ° (see FIG. 7 (b)).

  In the display device 10A of the present embodiment, the slow axis direction of the first retardation film 3A with respect to the absorption axis direction (0 °) of the polarizer 2 is 40 ° to 50 ° or − with counterclockwise rotation as positive. It is set in the range of 50 ° to -40 °, more preferably 45 ° or -45 ° (see FIGS. 7 (a) and 7 (b)).

  With respect to the bending direction of the display device 10A, the absorption axis direction of the polarizer 2 is set to make an angle α with respect to the bending direction of the display device 10A as shown in FIGS. 6 (a) to 6 (d). It is done. That is, the circularly polarizing plate 1 is disposed on the surface of the display panel 20 such that the absorption axis direction of the polarizer 2 is at an angle α with respect to the bending direction of the display device 10A.

  Specifically, the angle α is in the range of −5 ° to 5 ° or 85 ° to 95 °, preferably 0 ° or 90 °, with counterclockwise rotation from the absorption axis direction (0 °) of the polarizer 2 being positive. It is set to be °°. By adjusting the absorption axis direction (angle α) of the polarizer 2 so as to be in such a range, it is possible to suppress a color change due to bending.

  Relationship between the bending direction (the direction orthogonal to the bending start line L) of the display device 10B and the absorption axis direction of the polarizer 2, and the slow axis direction of the λ / 2 plate 3B and the slow axis of the λ / 4 plate 4B The relationship between the directions will be described with reference to FIGS. 8 (a) and 8 (b). 8A and 8B show the relationship between the bending direction of the display device 10B and the absorption axis direction of the polarizer 2, and the slow axis direction of the λ / 2 plate 3B and the λ / 4 plate 4B. It is a schematic diagram for demonstrating the relationship of a slow axis direction. 8 (a) and 8 (b), the absorption axis direction of the polarizer 2 is indicated by "broken line", and the slow axis direction of the λ / 2 plate 3B is indicated by "one-dot chain line". The slow axis direction of 4B is indicated by "solid line".

  In the display device 10B, as shown in FIGS. 8A and 8B, linear bending start lines L positioned at least at the flat portion 10a and at the end of the flat portion 10a (FIGS. 8A and 8B). And a bent portion 10b which is bent along a direction (bending direction) orthogonal to the bending start line L). In this case, the bending direction of the display device 10B is a straight bending start line L when the display device 10B is viewed from the normal direction of the flat portion 10a (the Z-axis direction in FIGS. 8A and 8B). This corresponds to the direction (Y-axis direction in FIGS. 8A and 8B) orthogonal to the above.

  In the display device 10B according to the present embodiment, the bending direction of the display device 10B is −10 ° to 10 ° positive with respect to the slow axis direction (0 °) of the λ / 4 plate 4B, as shown in FIG. a) 0 °) or 80 ° to 100 ° (FIG. 8 (b) 90 °), preferably -5 ° to 5 ° or 85 ° to 95 °, more preferably 0 ° or 90 ° It is set to.

  At this time, the slow axis direction of the λ / 2 plate 3B is set to make an angle α with the absorption axis direction of the polarizer 2. That is, the circularly polarizing plate 1B is disposed on the surface of the display panel 20 so that the slow axis direction of the λ / 2 plate 3B forms an angle α with the absorption axis direction of the polarizer 2.

  Furthermore, the slow axis direction of the λ / 4 plate 4B is set to form an angle β with the absorption axis direction of the polarizer 2. That is, the circularly polarizing plate 1B is disposed on the surface of the display panel 20 so that the slow axis direction of the λ / 4 plate 4B is at an angle β with respect to the absorption axis direction of the polarizer 2. The angle α and the angle β are both angles based on the absorption axis of the polarizer 2 and counterclockwise as positive. When the slow axis direction of the λ / 4 plate 4 is positive counterclockwise with respect to the absorption axis direction (0 °) of the polarizer 2, the angle β is −20 ° to 20 ° (FIGS. In b), it is set in the range of -15 °).

  Specifically, a preferable combination of the angle α and the angle β will be described. The angle α is preferably −80 ° to −70 °, more preferably −78 ° to −70 °, and still more preferably −76 ° to −70 °. At this time, the angle β is preferably −20 ° to −10 °, more preferably −18 ° to −10 °, and still more preferably −16 ° to −10 °.

  The angle α is preferably 80 ° to 70 °, more preferably 78 ° to 70 °, and still more preferably 76 ° to 70 °. At this time, the angle β is preferably 20 ° to 10 °, more preferably 18 ° to 10 °, and still more preferably 16 ° to 10 °.

  By adjusting the slow axis direction (angle α) of the λ / 2 plate 3B and the slow axis direction (angle β) of the λ / 4 plate 4B so as to be in such a range, the color change due to bending is suppressed It is possible.

[Hue change of circular polarizer before and after bending]
By the way, in the circularly polarizing plates 1A and 1B of the present embodiment, the hues of the reflected light obtained before and after bending are the a ^* coordinate axis and the b ^* coordinate axis in the a ^* b ^* chromaticity coordinates of the CIE1976 L ^* a ^* b ^* color space. It is characterized in that the code does not change in between. That is, the hue of the reflected light obtained before and after bending is set to a value that does not straddle the a ^* coordinate axis in the a ^* b ^* chromaticity coordinate and does not straddle the b ^* coordinate axis. Thereby, even if the hue of the reflected light obtained before and after bending changes, it is possible to make the change in the hue inconspicuous.

In addition, even if at least one of the a ^* value and the b ^* value is 0 before and after the start of bending, it is assumed that the sign does not change before and after bending if the other sign does not change. That is, in this case, it is assumed that there is no straddling of the a ^* coordinate axis and the b ^* coordinate axis.

When the display devices 10A and 10B are bent so that the circularly polarizing plates 1A and 1B of this embodiment are on the outside (OUT), and so that the circularly polarizing plates 1A and 1B of this embodiment are on the inside (IN) in the case of at least one of a case formed by bending the display device 10A, the 10B, the hue of the reflected light obtained before and after bending, the code changes across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates It is preferable not to do so, and in any case, it is more preferable that the sign does not change.

Specifically, the hue change of the reflected light obtained before and after the bending of the circularly polarizing plates 1A and 1B will be described with reference to FIG. FIG. 9 is an a ^* b ^* chromaticity coordinate diagram for explaining the hue change of the reflected light obtained before and after bending of the circularly polarizing plates 1A and 1B.

  With regard to the hue change of the reflected light obtained before and after the bending of the circularly polarizing plates 1A and 1B, it is possible to evaluate the hue close to visual observation by using the method of measuring the hue by removing specularly reflected light called SCE method. preferable.

The measurement of the reflection hue can be performed by CM-2600 d (a spectrocolorimeter manufactured by Konica Minolta Co., Ltd.). According to "JIS Z 8722", the setting conditions can be as follows.
Light source: D65 light source
・ Measurement diameter: 8 mmφ
・ Field of view: 2 °
・ Geometric condition: Geometric condition c

Further, in the present embodiment, a reflection plate of aluminum is disposed on the surface of the circularly polarizing plates 1A and 1B on the opposite side to the polarizer 2 side via the PSA layer 9 to measure the hue by the SCE method before bending. Do. That is, in the case of the circularly polarizing plate 1A shown in FIG. 1, an aluminum reflecting plate is disposed on the surface on the second retardation film 4A side via the PSA layer 9. On the other hand, in the case of the circularly polarizing plate 1B shown in FIG. 3, a reflection plate of aluminum is disposed on the surface on the retardation layer RF side via the PSA layer 9. Thereafter, the radius of curvature when bending the circularly polarizing plates 1A and 1B is 5 mm, and after at least one bending, aluminum is reflected again to the surface of the circularly polarizing plates 1A and 1B opposite to the polarizer 2 side. Place the plate and measure the hue by the SCE method after bending. Then, the circularly polarizing plate 1A, the change in hue 1B bent back and forth in the resulting reflected light, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates.

In the present embodiment, with respect to the hue of the reflected light obtained before and after bending, the case where the sign does not change across the a ^* coordinate axis and the b ^* coordinate axis in the a ^* b ^* chromaticity coordinates is, for example, a ^* b shown in FIG. ^{In the} chromaticity coordinate diagram, it is synonymous with not crossing the quadrant across the a ^* coordinate axis and the b ^* coordinate axis in the a ^* b ^* chromaticity coordinate. In this case, even if the hues of the circularly polarizing plates 1A and 1B change before and after bending, the change in the hue can be made inconspicuous. On the other hand, when the quadrant is crossed with the a ^* coordinate axis or the b ^* coordinate axis in the a ^* b ^* chromaticity coordinates, the change in hue is easily seen.

In the circularly polarizing plate 1A, 1B of the present embodiment, the hue of the reflected light obtained before and after such a bending, is set to a value that does not cross the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates There is. The circularly polarizing plates 1A and 1B can change the hue by adjusting the hue of the polarizing plate 2 or adjusting the retardation value of the circularly polarizing plates 1A and 1B. In addition, adjusting the wavelength dispersion of the retardation film is also effective for controlling the hue. For example, when the retardation value of the circularly polarizing plates 1A and 1B is increased, the a ^* value and the b ^* value decrease, and when the retardation value of the circularly polarizing plates 1A and 1B is decreased, the a ^* value and b ^{* Increase in} value.

The hue of the polarizing plate (a laminate comprising the polarizer 2 and the protective films 5 and 6 bonded to the one side or both sides with the adhesive layer 8 via the adhesive layer 8) is expressed in the Hunter 1948 Lab color space and is orthogonal to the bending before bending. The a value is preferably −10 or more and 10 or less, and more preferably −5 or more and 5 or less. Moreover, it is preferable that the orthogonal b value before bending is -25 or more and 0 or less, and it is more preferable that it is -20 or more and 0 or less. The setting conditions for measuring the hue of the polarizing plate can be as follows.
Light source: C light source
・ Field of view: 2 °
Within the above range, there is no problem in the initial reflection hue, and the combination of the bending direction and the retardation value of the retardation film makes it easy to adjust so as not to cross the quadrant before and after bending.

In the circularly polarizing plates 1A and 1B of the present embodiment, the a ^* value is preferably −8 or more and 8 or less, and more preferably −5 or more and 5 or less in the reflection hue before bending. On the other hand, in the circularly polarizing plates 1A and 1B of the present embodiment, the b ^* value is preferably −10 or more and 0 or less, and more preferably −5 or more and 0 or less in the reflection hue before bending.

In the circularly polarizing plates 1A and 1B of the present embodiment, the a ^* value is preferably −8 or more and 8 or less, and more preferably −5 or more and 5 or less in the reflection hue after bending. On the other hand, in the circularly polarizing plates 1A and 1B of the present embodiment, the b ^* value is preferably −10 or more and 0 or less, and more preferably −5 or more and 0 or less in the reflection hue after bending.

In the circularly polarizing plates 1A and 1B of the present embodiment, the color difference value obtained from the difference Δa ^* and Δb ^* between the a ^* value and the b ^* value is preferably 0 or more and 5 or less in the reflected hue before and after bending. More preferably, it is 3 or less. The color difference value is calculated from [(Δa ^* ) ² + (Δb ^* ) ² ] ^1/2 .

In addition, this invention is not necessarily limited to the thing of the said embodiment, It is possible to add a various change in the range which does not deviate from the meaning of this invention.
For example, a touch sensor may be provided as an input unit of the display devices 10A and 10B. Specifically, as in the display device 30 shown in FIG. 10, in addition to the configuration of the display devices 10A and 10B, the touch sensor 40 and the window film 50 can be provided. FIG. 10 is a cross-sectional view showing another configuration example of the bendable display device 30 provided with the circularly polarizing plates 1A and 1B. The circularly polarizing plate may be the circularly polarizing plate 1A shown in FIG. 1 or the circularly polarizing plate 1B shown in FIG.

  In the display device 30 shown in FIG. 10, the touch sensor 40 is preferably disposed on the side facing the display panel 20 of the circularly polarizing plates 1A and 1B, and the window film 50 displays the circularly polarizing plates 1A and 1B. It is preferable to arrange | position on the opposite side to the side which opposes the panel 20. FIG. When circularly polarizing plates 1A and 1B are present on the viewing side of the touch sensor 40, the pattern of the touch sensor 40 is less likely to be viewed, and the visibility of the image displayed on the display panel 20 is improved.

  Therefore, the display device 30 shown in FIG. 10 has a configuration in which the display panel 20, the touch sensor 40, the circularly polarizing plates 1A and 1B, and the window film 50 are stacked in this order using an adhesive or a pressure sensitive adhesive. There is. In addition, it is possible to provide a light shielding pattern described later on at least one surface of any of the window film 50, the circularly polarizing plates 1A and 1B, and the touch sensor 40.

  The order in which the touch sensor 40 and the window film 50 are stacked is not necessarily limited to the above-described configuration. For example, the order of the display panel 20, the circularly polarizing plates 1A and 1B, the touch sensor 40, and the window film 50 It is also possible to have a laminated structure.

  The window film 50 may be the protective film 5 constituting the circularly polarizing plates 1A and 1B described above, and even if the window film 50 doubles as the protective film 5 of the circularly polarizing plates 1A and 1B. Good.

  Further, in the present invention, although not shown, in addition to the configuration of the display device 10, the touch sensor 40 may be provided on the side opposite to the side facing the display panel 20 of the circularly polarizing plate 1. It is possible.

(Window film)
The window film 50 is disposed on the viewing side of the bendable display 30, and plays a role of a protective layer that protects the other components from external impact or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but the window film 50 in the bendable display 30 is not rigid and rigid like glass, but has bendable characteristics. .

  The window film 50 has a bendable transparent substrate 51 and a hard coat layer 52 provided on at least one surface of the transparent substrate 51. In the display device 30 shown in FIG. 10, the hard coat layer 52 constituting the window film 50 is provided on the surface of the transparent base 51 opposite to the circularly polarizing plates 1A and 1B. The hard coat layer 52 is the outermost layer of the display device 30 and is in contact with the outside air (air). In addition, the hard coat layer 52 may be provided on the surface of the transparent base material 51 on the side of the circularly polarizing plates 1A and 1B. Furthermore, the hard coat layer 52 may be provided only on one side of the transparent substrate 51 or may be provided on both sides of the transparent substrate 51.

(Transparent substrate)
The transparent substrate 51 has a visible light transmittance of 70% or more, preferably 80% or more. The thickness of the transparent substrate 51 is 5 to 200 μm, preferably 20 to 100 μm.

  As the transparent substrate 51, any transparent polymer film can be used. Specifically, polyolefins such as polyethylene, polypropylene, polymethylpentene, norbornene, or cycloolefin derivatives having a unit of a monomer containing cycloolefin, diacetyl cellulose, triacetyl cellulose, propionyl cellulose, etc. Acrylics such as celluloses, methyl methacrylate (co) polymers, polystyrenes such as styrene (co) polymers, acrylonitrile butadiene styrene copolymers, acrylonitrile styrene copolymers, ethylene-vinyl acetate copolymer Copolymers, polyvinyl chlorides, polyvinylidene chlorides, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyesters such as polycarbonate and polyarylate, polyamides such as nylon , Polyimides, polyamides imides, polyether imides, polyether sulfones, polysulfones, polyvinyl alcohols, polyvinyl acetals, polyurethanes, mention may be made of polymer in formed films such as epoxy resins. Moreover, these unstretched films, uniaxially stretched films, or biaxially stretched films can be used.

  For the transparent substrate 51, these polymers can be used alone or in combination of two or more. Preferably, among the transparent substrates 51 described above, it is preferable to use a polyamide film, a polyamideimide film or a polyimide film, a polyester film, an olefin film, an acrylic film, a cellulose film excellent in transparency and heat resistance. .

  It is also preferable to disperse inorganic particles such as silica, organic fine particles, rubber particles and the like in the polymer film. Furthermore, colorants such as pigments and dyes, fluorescent whitening agents, dispersants, plasticizers, heat stabilizers, light stabilizers, infrared absorbers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. The following ingredients may be contained.

(Hard coat layer)
The thickness of the hard coat layer 52 is not particularly limited, but preferably 2 to 100 μm, for example. If the thickness of the hard coat layer 52 is less than 2 μm, it will be difficult to secure sufficient scratch resistance. On the other hand, when the thickness of the hard coat layer 52 exceeds 100 μm, the bending resistance may be reduced, and a problem of curling due to curing shrinkage may occur.

  The hard coat layer 52 can be formed by curing of a hard coat composition containing a reactive material that forms a crosslinked structure by irradiation with active energy rays or thermal energy, but that is cured by irradiation with active energy rays preferable.

  An active energy ray is defined as an energy ray capable of decomposing a compound that generates an active species to generate an active species. As active energy rays, visible light, ultraviolet rays, infrared rays, X rays, α rays, β rays, γ rays, electron rays and the like can be mentioned. Among them, ultraviolet light is particularly preferred.

  The hard coat composition contains a polymer of at least one of a radically polymerizable compound and a cationically polymerizable compound. The radically polymerizable compound is a compound having a radically polymerizable group. As a radically polymerizable group which a radically polymerizable compound has, it should just be a functional group which can produce a radical polymerization reaction, and the group containing a carbon-carbon unsaturated double bond etc. are mentioned. Specifically, a vinyl group, a (meth) acryloyl group, etc. are mentioned.

  In addition, when the said radically polymerizable compound has 2 or more radically polymerizable groups, these radically polymerizable groups may be respectively the same, and may differ. The number of radically polymerizable groups that the radically polymerizable compound has in one molecule is preferably two or more from the viewpoint of improving the hardness of the hard coat layer 52.

  As a radically polymerizable compound, a compound having a (meth) acryloyl group is preferable from the viewpoint of high reactivity, and is referred to as a polyfunctional acrylate monomer having 2 to 6 (meth) acryloyl groups in one molecule. And oligomers having a molecular weight of several hundred to several thousand having several (meth) acryloyl groups in a molecule called epoxy (meth) acrylate, urethane (meth) acrylate or polyester (meth) acrylate can be preferably used . It is preferable to include one or more selected from epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate.

  The cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, and a vinyl ether group. The number of cationically polymerizable groups that the cationically polymerizable compound has in one molecule is preferably 2 or more, and more preferably 3 or more from the viewpoint of improving the hardness of the hard coat layer 52. Moreover, as a cationically polymerizable compound, the compound which has at least 1 sort (s) of an epoxy group and oxetanyl group as a cationically polymerizable group is preferable.

  A cyclic ether group such as an epoxy group or an oxetanyl group is preferable from the viewpoint of small shrinkage associated with the polymerization reaction. In addition, compounds having an epoxy group among cyclic ether groups are easy to obtain compounds of various structures, do not adversely affect the durability of the obtained hard coat layer 52, and also control their compatibility with radically polymerizable compounds. It has the advantage of being easy to do.

  Further, among the cyclic ether group, oxetanyl group tends to have a high degree of polymerization as compared with the epoxy group, has low toxicity, and accelerates the network formation rate obtained from the cationically polymerizable compound of the obtained hard coat layer 52 Even in the region mixed with the radically polymerizable compound, there is an advantage such as forming an independent network without leaving unreacted monomers in the film.

  As a cationically polymerizable compound having an epoxy group, for example, polyglycidyl ether of polyhydric alcohol having an alicyclic ring or a cyclohexene ring or cyclopentene ring-containing compound with a suitable oxidizing agent such as hydrogen peroxide or a peracid Alicyclic epoxy resin obtained by epoxidation; polyglycidyl ether of aliphatic polyhydric alcohol or its alkylene oxide adduct, polyglycidyl ester of aliphatic long chain polybasic acid, homopolymer of glycidyl (meth) acrylate, Aliphatic epoxy resins such as copolymers; bisphenols such as bisphenol A, bisphenol F and hydrogenated bisphenol A, or their derivatives such as alkylene oxide adducts, caprolactone adducts and the like; glycidyl produced by reaction with epichlorohydrin Ether, and a novolak epoxy resin, glycidyl ether type epoxy resins derived from bisphenols are exemplified.

  The hard coat composition can further comprise a polymerization initiator. As a polymerization initiator, a radical polymerization initiator, a cationic polymerization initiator, a radical, a cationic polymerization initiator etc. can be mentioned, It can select suitably from it and can use. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations to advance radical polymerization and cationic polymerization.

  The radical polymerization initiator may be capable of releasing a substance that initiates radical polymerization by at least one of active energy ray irradiation and heating. For example, as the thermal radical polymerization initiator, organic peroxides such as hydrogen peroxide and perbenzoic acid, and azo compounds such as azobisbutyronitrile can be mentioned.

  As active energy ray radical polymerization initiators, Type 1 type radical polymerization initiators that generate radicals by molecular decomposition, and Type 2 type radical polymerization initiators that generate radicals by hydrogen abstraction reaction in coexistence with tertiary amines They can be used alone or in combination.

  The cationic polymerization initiator may be capable of releasing a substance that initiates cationic polymerization by at least one of active energy ray irradiation and heating. As the cationic polymerization initiator, aromatic iodonium salts, aromatic sulfonium salts, cyclopentadienyl iron (II) complexes and the like can be used. Depending on the difference in structure, these can initiate cationic polymerization either by active energy ray irradiation or heating, or by either.

  The polymerization initiator can comprise 0.1 to 10% by weight based on the total (100% by weight) of the hard coat composition. If the content of the polymerization initiator is less than 0.1% by weight, curing can not proceed sufficiently, and it is difficult to realize the mechanical properties and adhesion of the finally obtained coating film. On the other hand, if the content of the polymerization initiator exceeds 10% by weight, adhesion failure due to curing shrinkage, cracking and curling may occur.

  The hard coat composition can further include one or more selected from the group consisting of a solvent and an additive. The solvent can dissolve or disperse the polymerizable compound and the polymerization initiator, and any solvent known as a solvent for hard coat compositions in the technical field can be used without limitation. The additives may further include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

(Touch sensor)
As the touch sensor 40, various types of sensors such as a resistive film type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, and a capacitance type have been proposed, and any type may be used. Among them, the capacitance method is preferable.

  The capacitive touch sensor 40 is divided into an active area and a non-active area located at an outer portion of the active area. The active area is an area corresponding to an area (display unit) in which a screen is displayed on the display panel 20, and is an area where a user's touch is sensed. On the other hand, the non-active area is an area corresponding to an area (non-display portion) in which the screen is not displayed on the display panel 20.

  The touch sensor 40 is formed on a substrate having flexible characteristics, a sensing pattern formed on an active area of the substrate, and a non-active area of the substrate, and is connected to an external driving circuit through the sensing pattern and the pad portion. And each of the sensing lines. A substrate made of a polymer material is usually used as a substrate of the touch sensor 40.

  As a substrate having a flexible property, the same material as the transparent substrate 51 of the window film 50 can be used. The substrate of the touch sensor 40 preferably has a toughness of 2000 MPa% or more from the viewpoint of suppressing a crack. More preferably, the toughness is 2000 to 300000 MPa%.

  The toughness of the substrate is the stress obtained by plotting the stress (MPa) [vertical axis] against the strain (%) [horizontal axis] obtained through the tensile test of the polymer material constituting the substrate Stress-strain curve is defined as the area under the curve to the breaking point. It is desirable from the viewpoint of crack suppression of the touch sensor 40 that the substrate constituting the touch sensor 40 have the above-mentioned toughness.

  The sensing pattern may include a first pattern formed in a first direction and a second pattern formed in a second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed in the same layer, and in order to sense a point to be touched, the respective patterns must be electrically connected.

  The first pattern is a form in which each unit pattern is connected to each other through a joint. On the other hand, the second pattern has a structure in which each unit pattern is separated from each other in an island form. Therefore, a separate bridge electrode is required to electrically connect the second pattern.

  The sensing pattern can apply a known transparent electrode material. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), PEDOT (poly (3, 4- ethylenedioxythiophene)), carbon nanotubes (CNTs), graphene, metal wires and the like. Moreover, these can be used individually or in mixture of 2 or more types. Among them, it is preferable to use ITO.

  The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, terenium, chromium and the like. Moreover, these can be used individually or in mixture of 2 or more types.

  The bridge electrode can be formed on the top of the sensing pattern through the insulating layer. Also, a bridge electrode can be formed on the substrate, and an insulating layer and a sensing pattern can be formed thereon.

  The bridge electrode can also be formed of the same material as the sensing pattern, for example, a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium or an alloy of two or more of these It can also be formed by

  Since the first pattern and the second pattern have to be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joint of the first pattern and the bridge electrode, or may be formed in a layer covering the sensing pattern. In the latter case, the bridge electrode can be connected to the second pattern through the contact hole formed in the insulating layer.

  The touch sensor 40 detects the light transmission induced by the difference in transmittance between the pattern area in which the pattern is formed and the non-pattern area in which the pattern is not formed, specifically, the difference in refractive index in these areas. An optical tuning layer can further be included between the substrate and the electrode as a means to properly compensate for the difference in rates.

  The optical adjustment layer may include an inorganic insulating material or an organic insulating material. The optical control layer can be formed by coating a photocurable composition containing a photocurable organic binder and a solvent on a substrate. The photocurable composition can further comprise inorganic particles. The refractive index of the optical control layer can be increased by the inorganic particles.

  The photocurable organic binder can include, for example, a copolymer of monomers such as an acrylate monomer, a styrene monomer, and a carboxylic acid monomer. The photocurable organic binder may be, for example, a copolymer containing mutually different repeating units such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit.

  The inorganic particles can include, for example, zirconia particles, titania particles, alumina particles, and the like. The photocurable composition may further contain various additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

(adhesive)
Examples of the adhesive include water-based adhesives, organic solvents, non-solvent adhesives, solid adhesives, solvent volatilization adhesives, moisture curing adhesives, heat curing adhesives, anaerobic curing, active energy ray curing An adhesive, a curing agent mixed adhesive, a heat melting adhesive, a pressure sensitive adhesive (pressure sensitive adhesive), a rewet adhesive, etc. can be used. Among them, water-based adhesives, active energy ray-curable adhesives and the like are often used. As the water-based adhesive and the active energy ray-curable adhesive, those described above can be used.

(Adhesive)
The pressure-sensitive adhesive may be classified into an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive and the like depending on the main agent polymer. In addition to the main agent polymer, a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, a tackifier, a plasticizer, a dye, a pigment, an inorganic filler and the like may be added to the adhesive.

  Each component constituting the pressure-sensitive adhesive is dissolved and dispersed in a solvent to obtain a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition is coated on a substrate and then dried to form a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer may be formed directly, or the one formed on the substrate may be separately transferred.

  In order to cover the adhesive surface before bonding, it is also preferable to use a release film. The thickness of the adhesive layer in the case of using an active energy ray-curable adhesive is 0.1 to 500 μm, preferably 1 to 300 μm. When a plurality of pressure-sensitive adhesives are used, the thickness and type of each layer may be the same or different.

(Light blocking pattern)
The light blocking pattern can be applied as at least a part of the bezel or the housing of the bendable display device 30. The visibility of the image is improved by hiding the wiring disposed at the peripheral portion of the display device 30 which can be bent by the light shielding pattern and making it difficult to be visually recognized.

  The light blocking pattern may be in the form of a single layer or multiple layers. The color of the light shielding pattern is not particularly limited, and has various colors such as black, white and metal. The light shielding pattern may be formed of a pigment for realizing a color, and a polymer such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, and silicone. Also, they can be used alone or in combination of two or more.

  The light shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light shielding pattern is 1 μm to 100 μm, preferably 2 μm to 50 μm. Further, it is also preferable to provide a shape such as inclination in the thickness direction of the light pattern.

  Hereinafter, the effects of the present invention will be made more apparent by examples. The present invention is not limited to the following examples, and can be appropriately modified and implemented without changing the gist of the invention.

Example 1
(Preparation of polarizer)
After a long polyvinyl alcohol film is dyed in an aqueous solution containing iodine, it is uniaxially stretched 6 times between rolls having different speed ratios in an aqueous solution containing boric acid, and a long sheet having an absorption axis in the longitudinal direction -Shaped polarizer was obtained. The elongated polarizer was stretched and then wound to form a wound body. The chromaticity of this polarizer is orthogonal a = 0.04, orthogonal b = -0.11, and the degree of visibility correction polarization of the polarizer is about 99.995%, and the degree of visibility correction of the polarizer alone The transmittance was 42.7%.

(Protective film)
As a protective film, a long triacetyl cellulose film (thickness 40 μm, manufactured by Konica Minolta, trade name: KC4UYW) was used. This protective film was prepared as a wound body. The in-plane retardation value Re (550) of this protective film was 5 nm, and the retardation value Rth (550) in the thickness direction was 45 nm.

(First phase difference film)
As the first retardation film, a film comprising a layer in which a liquid crystal compound was cured and an alignment film was used. The first retardation film was a λ / 4 plate, Re (450) / Re (550) was less than 1.0, and Re (650) / Re (550) was more than 1.0.

(2nd retardation film)
As a second retardation film, a film composed of a layer in which a liquid crystal compound was cured and an alignment film was used. This second retardation film is a positive C plate.

(UV-curable adhesive)
The following components were mixed and defoamed to prepare a UV-curable adhesive.
70 parts by mass of 3 ', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (trade name: CEL 2021 P, manufactured by Daicel Corporation)
Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase ChemteX Co., Ltd.): 20 parts by mass
2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Co., Ltd.): 10 parts by mass
Cationic polymerization initiator (trade name: CPI-100, manufactured by San-Apro Corporation): 2.25 parts by mass of solid content (blended as a 50% propylene carbonate solution)
1,4-diethoxynaphthalene: 2 parts by mass

(Preparation of circularly polarizing plate)
The polarizer, the protective film, the first retardation film, and the second retardation film were cut out to 200 mm × 300 mm, respectively, and then protective films were attached to both sides of the polarizer through a polyvinyl alcohol-based adhesive. The first retardation film and the second retardation film were bonded to each other via the above-mentioned ultraviolet-curable adhesive (adhesive layer). Furthermore, the first retardation film and the protective film were bonded via an acrylic pressure-sensitive adhesive layer (PSA layer). An acrylic pressure-sensitive adhesive layer (PSA layer) with a release film was attached to the second retardation film. As described above, a circularly polarizing plate in which a protective film, a polarizer, a protective film, a PSA layer, a first retardation film, a UV adhesive layer, a second retardation film, and a PSA layer were sequentially laminated was produced. .

  In addition, the first retardation film (λ / 4 plate) is a polarizer so that the slow axis direction thereof is −45 °, with counterclockwise rotation from the absorption axis direction (0 °) of the polarizer as positive. It is pasted to. Furthermore, the bending direction of the circularly polarizing plate (direction orthogonal to the bending start line L) is -45 ° with respect to the absorption axis direction (0 °) of the polarizer, and the first retardation film (λ / 4) It is adjusted to be 0 ° with respect to the slow axis direction of the plate). Thereafter, the produced circularly polarizing plate was trimmed to a size of 20 mm × 80 mm.

(Preparation of sample for evaluation)
After removing the peeling film from the circularly polarizing plate of Example 1, the pressure-sensitive adhesive surface was attached to a mat surface of an aluminum foil (manufactured by UACJ, trade name "My foil (registered trademark)") to obtain a sample for evaluation . With respect to the evaluation sample obtained in this manner, an evaluation test was conducted to measure the hue before and after bending and to observe the change in tint before and after bending.

(Measurement of hue)
First, the reflection hue of the sample for evaluation was measured by the SCE method before bending to obtain the a ^* value and the b ^* value before bending. Thereafter, while pressing a mandrel having a diameter of 5 mm against the organic EL display device alternative side, the circularly polarizing plate was bent along the circumferential surface of the mandrel so as to be the outer side (OUT) with respect to the aluminum foil. Then, after bending, the bending state was eliminated (in a flat state), and the reflected hue was measured by the SCE method to obtain a ^* and b ^* values after bending.

(Observation of color)
The color before and after bending was visually observed to evaluate the visibility of the color change. In Table 1, the evaluation is ○ when color change is difficult to visually recognize, and the evaluation is × when it is easy to visually recognize.

The summary of Example 1 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 1. FIG.
In Example 1, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

(Measurement of storage modulus of adhesive layer test piece at temperature of 30 ° C)
First, a first retardation film and a second retardation film are bonded to one side of a 50 μm-thick cyclic polyolefin resin film using a coating machine (Bar Coater, manufactured by Daiichi Rika Co., Ltd.) The UV curable adhesive used for this purpose was coated, and a cyclic polyolefin resin film with a thickness of 50 μm was further laminated on the coated surface.

Next, ultraviolet rays were irradiated using an “H bulb” manufactured by Fusion UV Systems, Inc. so that the integrated light quantity would be 1500 mJ / cm ² (UVB), and the adhesive layer was cured. The thickness of the adhesive layer was 30 μm. This was cut into a size of 5 mm × 30 mm, and both sides of the cyclic polyolefin resin film were peeled off to obtain a cured film of an adhesive.

  This cured film is held at a distance of 2 cm between the grips using a dynamic viscoelasticity measuring apparatus "DVA-220" manufactured by IT Measurement & Control Co., Ltd. so that the long side is in the tensile direction, and the tension and contraction are achieved. The storage modulus was determined at a temperature of 30 ° C., with a frequency of 10 Hz and a measurement temperature of 30 ° C. The storage elastic modulus at a temperature of 30 ° C. of the adhesive layer test piece was 2060 MPa.

Example 2
In Example 2, the bending direction of the circularly polarizing plate is 45 ° with respect to the absorption axis direction (0 °) of the polarizer, and with respect to the slow axis direction of the first retardation film (λ / 4 plate) An evaluation sample similar to that of Example 1 was produced except that adjustment was made to be 90 °. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Example 2 is shown in Table 1 below. Further, FIG. 11 shows the hue change before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 2.
In Example 2, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 3]
In Example 3, the bending direction of the circularly polarizing plate is −45 ° with respect to the absorption axis direction (0 °) of the polarizer, and with respect to the slow axis direction of the first retardation film (λ / 4 plate). The sample for evaluation was the same as that of Example 1 except that the phase difference value of the λ / 4 plate was changed by adjusting to 0 °. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Example 3 is shown in Table 1 below. Further, FIG. 11 shows a hue change before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 3.
In Example 3, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

Example 4
(Λ / 2 plate)
As the λ / 2 plate, a film comprising a layer in which a liquid crystal compound was cured and an alignment film was used.

(Λ / 4 plate)
As the λ / 4 plate, a film comprising a layer in which the liquid crystal compound was cured and an alignment film was used.

(Preparation of circularly polarizing plate)
The polarizer, the protective film, the λ / 2 plate and the λ / 4 plate were cut out to 200 mm × 300 mm, respectively, and then protective films were attached to both sides of the polarizer via a polyvinyl alcohol-based adhesive. The λ / 2 plate and the λ / 4 plate were pasted together via the above-mentioned UV curable UV adhesive (adhesive layer). Furthermore, the λ / 2 plate and the protective film were bonded via an acrylic pressure-sensitive adhesive layer (PSA layer). An acrylic pressure-sensitive adhesive layer (PSA layer) with a release film was attached to the λ / 4 plate. As described above, a circularly polarizing plate was produced in which a protective film, a polarizer, a protective film, a PSA layer, a λ / 2 plate, a UV adhesive layer, a λ / 4 plate, and a PSA layer were sequentially laminated.

  The λ / 4 plate is bonded to the polarizer such that the slow axis direction thereof is −15 °, with the anticlockwise direction as positive from the absorption axis direction (0 °) of the polarizer. Furthermore, the bending direction of the circularly polarizing plate is adjusted to 45 ° with respect to the absorption axis direction (0 °) of the polarizer and to 60 ° with respect to the slow axis direction of the λ / 4 plate. Thereafter, the produced circularly polarizing plate was trimmed to a size of 20 mm × 80 mm.

  After removing the peeling film from the circularly polarizing plate of Example 4, the pressure-sensitive adhesive surface was attached to a matte surface of an aluminum foil (trade name "My foil (registered trademark)" manufactured by UACJ, Inc.) to obtain a sample for evaluation . The evaluation test similar to Example 1 was performed about the sample for evaluation obtained in this way.

The summary of Example 4 is shown in Table 1 below. Further, FIG. 11 shows the hue change before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 4.
In Example 4, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 5]
In Example 5, the bending direction of the circularly polarizing plate is -45 ° with respect to the absorption axis direction (0 °) of the polarizer, and -30 ° with respect to the slow axis direction of the λ / 4 plate. An evaluation sample similar to that of Example 4 was produced except that it was adjusted. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Example 5 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 5.
In Example 5, hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 6]
In Example 6, the bending direction of the circularly polarizing plate is adjusted to 45 ° with respect to the absorption axis direction (0 °) of the polarizer and to 60 ° with respect to the slow axis direction of the λ / 4 plate. The same evaluation sample as in Example 4 was produced except that the retardation value of the λ / 4 plate was changed. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 6 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 6. FIG.
In Example 6, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 7]
In Example 7, the bending direction of the circularly polarizing plate is -45 ° with respect to the absorption axis direction (0 °) of the polarizer, and -30 ° with respect to the slow axis direction of the λ / 4 plate. The same evaluation sample as that of Example 4 was produced except that adjustment was performed and the retardation value of the λ / 4 plate was changed. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 7 is shown in Table 1 below. Further, FIG. 11 shows the hue change before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 7. FIG.
In Example 7, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 8]
In Example 8, the bending direction of the circularly polarizing plate is 0 ° with respect to the absorption axis direction (0 °) of the polarizer, and with respect to the slow axis direction of the first retardation film (λ / 4 plate). An evaluation sample similar to that of Example 1 was produced except that adjustment was made to be 45 °. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Example 8 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 8. FIG.
In Example 8, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 9]
In Example 9, the bending direction of the circularly polarizing plate is 90 ° with respect to the absorption axis direction (0 °) of the polarizer, and with respect to the slow axis direction of the first retardation film (λ / 4 plate). The same evaluation sample as that of Example 1 was produced except that the angle was adjusted to −45 °. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Example 9 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 9. FIG.
In Example 9, the change in hue of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 10]
In Example 10, the bending direction of the circularly polarizing plate is adjusted to be -15 ° to the absorption axis direction (0 °) of the polarizer and to be 0 ° to the slow axis direction of the λ / 4 plate. The same evaluation sample as Example 4 was produced except having carried out. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Example 10 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 10. FIG.
In Example 10, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 11]
In Example 11, separately from Example 1, the following first retardation film was used as a λ / 4 plate. Moreover, the 1st retardation film and the 2nd retardation film were bonded together by the acrylic adhesive layer (PSA layer). The first retardation film was placed so that its slow axis was at an angle of −45 ° to the absorption axis of the polarizer. A circularly polarizing plate was produced in the same manner as in Example 1 except for the above.

(First phase difference film)
As the first retardation film, a film obtained by uniaxially stretching a film made of a resin containing polycarbonate was used. The in-plane retardation value Re (550) of this third retardation film is 143.5 nm, Re (450) / Re (550) is less than 1.0, and Re (650) / Re (550). Was over 1.0.

  In Example 11, the bending direction of the circularly polarizing plate is 0 ° with respect to the absorption axis direction (0 °) of the polarizer, and with respect to the slow axis direction of the first retardation film (λ / 4 plate). An evaluation sample similar to that of Example 1 was produced except that adjustment was made to be 45 °. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 11 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 11. FIG.
In Example 11, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 12]
In Example 12, the bending direction of the circularly polarizing plate is 45 ° with respect to the absorption axis direction (0 °) of the polarizer, and with respect to the slow axis direction of the first retardation film (λ / 4 plate) An evaluation sample similar to that of Example 11 was produced except that adjustment was made to be 90 °. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become the outside (OUT) to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 12 is shown in Table 1 below. Further, FIG. 11 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 12. FIG.
In Example 12, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 13]
In Example 13, the λ / 2 plate and the λ / 4 plate are respectively made of a film made of a cyclic olefin resin, and the λ / 2 plate and the λ / 4 plate are interposed with an acrylic pressure-sensitive adhesive layer (PSA layer). Pasted together. The λ / 4 plate is bonded to the polarizer such that the slow axis direction thereof is −15 °, with the anticlockwise direction as positive from the absorption axis direction (0 °) of the polarizer. Furthermore, the bending direction of the circularly polarizing plate is adjusted to 75 ° with respect to the absorption axis direction (0 °) of the polarizer and to 90 ° with respect to the slow axis direction of the λ / 4 plate. Other than that, the sample for evaluation similar to Example 4 was produced. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 13 is shown in Table 1 below. Further, FIG. 12 shows the hue change before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 13.
In Example 13, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

Example 14
In Example 14, the λ / 4 plate is bonded to the polarizer such that the slow axis direction thereof is −15 °, with the anticlockwise direction as positive from the absorption axis direction (0 °) of the polarizer. ing. Furthermore, the bending direction of the circularly polarizing plate is adjusted to -15 ° to the absorption axis direction (0 °) of the polarizer and to 0 ° to the slow axis direction of the λ / 4 plate. . An evaluation sample similar to that of Example 13 was produced except for that. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 14 is shown in Table 1 below. Further, FIG. 12 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 14. FIG.
In Example 14, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 15]
In Example 15, the λ / 4 plate is bonded to the polarizer such that the slow axis direction thereof is −15 °, with the anticlockwise direction as positive from the absorption axis direction (0 °) of the polarizer. ing. Furthermore, the bending direction of the circularly polarizing plate is adjusted to −45 ° to the absorption axis direction (0 °) of the polarizer and to −30 ° to the slow axis direction of the λ / 4 plate. There is. An evaluation sample similar to that of Example 13 was produced except for that. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 15 is shown in Table 1 below. Further, FIG. 12 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 15.
In Example 15, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 16]
In Example 16, the λ / 4 plate is bonded to the polarizer such that the slow axis direction is −15 °, counterclockwise from the absorption axis direction (0 °) of the polarizer (0 °). ing. Furthermore, the bending direction of the circularly polarizing plate is adjusted to 45 ° with respect to the absorption axis direction (0 °) of the polarizer and to 60 ° with respect to the slow axis direction of the λ / 4 plate. An evaluation sample similar to that of Example 13 was produced except for that. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 16 is shown in Table 1 below. Further, FIG. 12 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 16. FIG.
In Example 16, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 17]
In Example 17, the λ / 4 plate is bonded to the polarizer such that the slow axis direction is −15 °, with the anticlockwise direction as positive from the absorption axis direction (0 °) of the polarizer. ing. Furthermore, the bending direction of the circularly polarizing plate is adjusted to 75 ° with respect to the absorption axis direction (0 °) of the polarizer and to 90 ° with respect to the slow axis direction of the λ / 4 plate. An evaluation sample similar to that of Example 13 was produced except for that. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become the outside (OUT) to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 17 is shown in Table 1 below. Further, FIG. 12 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 17. FIG.
In Example 17, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 18]
In Example 18, the λ / 4 plate is bonded to the polarizer such that the slow axis direction is −15 °, with the anticlockwise direction as positive from the absorption axis direction (0 °) of the polarizer. ing. Furthermore, the bending direction of the circularly polarizing plate is adjusted to -15 ° to the absorption axis direction (0 °) of the polarizer and to 0 ° to the slow axis direction of the λ / 4 plate. . An evaluation sample similar to that of Example 13 was produced except for that. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become the outside (OUT) to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 18 is shown in Table 1 below. Further, FIG. 12 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 18. FIG.
In Example 18, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 19]
In Example 19, the λ / 4 plate is bonded to the polarizer such that the slow axis direction is −15 °, counterclockwise from the absorption axis direction (0 °) of the polarizer (0 °). ing. Furthermore, the bending direction of the circularly polarizing plate is adjusted to −45 ° to the absorption axis direction (0 °) of the polarizer and to −30 ° to the slow axis direction of the λ / 4 plate. There is. An evaluation sample similar to that of Example 13 was produced except for that. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become the outside (OUT) to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 19 is shown in Table 1 below. Further, FIG. 12 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 19. FIG.
In Example 19, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

[Example 20]
In Example 20, the λ / 4 plate is bonded to the polarizer such that the slow axis direction is −15 °, with the anticlockwise direction as positive from the absorption axis direction (0 °) of the polarizer. ing. Furthermore, the bending direction of the circularly polarizing plate is adjusted to 45 ° with respect to the absorption axis direction (0 °) of the polarizer and to 60 ° with respect to the slow axis direction of the λ / 4 plate. An evaluation sample similar to that of Example 13 was produced except for that. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become the outside (OUT) to aluminum foil along the peripheral surface of a mandrel.

The summary of Example 20 is shown in Table 1 below. Further, FIG. 12 shows hue changes before and after bending in the a ^* b ^* chromaticity coordinate diagram in Example 20.
In Example 20, the hue change of the resulting reflected light before and after bending of the circularly polarizing plate, it was confirmed that the sign does not change across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. It was also confirmed that the change in color was not noticeable.

Comparative Example 1
In Comparative Example 1, the bending direction of the circularly polarizing plate is 45 ° with respect to the absorption axis direction (0 °) of the polarizer, and with respect to the slow axis direction of the first retardation film (λ / 4 plate) An evaluation sample was prepared in the same manner as in Example 1 except that adjustment was made to be 90 °, and the retardation value of the λ / 4 plate was changed. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Comparative Example 1 is shown in Table 1 below. Further, for Comparative Example 1, the hue change before and after bending is illustrated in the a ^* b ^* chromaticity coordinate diagram in FIG.
In Comparative Example 1, the hue change of the reflected light obtained before and after bending of the circularly polarizing plate, it was confirmed that the sign has changed across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. In addition, it was possible to easily confirm the change in color tone.

Comparative Example 2
In Comparative Example 2, the bending direction of the circularly polarizing plate is adjusted to 45 ° with respect to the absorption axis direction (0 °) of the polarizer and to 60 ° with respect to the slow axis direction of the λ / 4 plate. The same evaluation sample as in Example 4 was produced except that the retardation value of the λ / 4 plate was changed. And about the sample for evaluation, the evaluation test similar to Example 1 was done.

The summary of Comparative Example 2 is shown in Table 1 below. Further, for Comparative Example 2, the hue change before and after bending is shown in the a ^* b ^* chromaticity coordinate diagram in FIG.
In Comparative Example 2, the change in hue of the reflected light obtained before and after bending of the circularly polarizing plate, it was confirmed that the sign has changed across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. In addition, it was possible to easily confirm the change in color tone.

Comparative Example 3
In Comparative Example 3, the bending direction of the circularly polarizing plate is -45 ° with respect to the absorption axis direction (0 °) of the polarizer, and -30 ° with respect to the slow axis direction of the λ / 4 plate. The same evaluation sample as that of Example 4 was produced except that adjustment was performed and the retardation value of the λ / 4 plate was changed. And about the sample for evaluation, the evaluation test similar to Example 1 was done except having bent so that a circularly-polarizing plate might become inner side (IN) with respect to aluminum foil along the peripheral surface of a mandrel.

The summary of Comparative Example 3 is shown in Table 1 below. Further, for Comparative Example 3, the hue change before and after bending is illustrated in the a ^* b ^* chromaticity coordinate diagram in FIG.
In Comparative Example 3, the change in hue of the reflected light obtained before and after bending of the circularly polarizing plate, it was confirmed that the sign has changed across the a ^* axis and b ^* axis in the a ^* b ^* chromaticity coordinates. In addition, it was possible to easily confirm the change in color tone.

[Evaluation]
As apparent from Table 1 and FIG. 11, according to Examples 1 to 10 of the present invention, the change of the hue (color tone) of the reflected light in the bent portion is made less noticeable than in Comparative Examples 1 to 3. Is possible.

  1A, 1B: Circularly polarizing plate 2. Polarizer 3A First retardation film (first retardation layer) 4A second retardation film (second retardation layer) 3B λ / 2 plate 1/2 wavelength plate) 4B λ / 4 plate (1/4 wavelength plate) 5, 6 protective film (protective layer) 7 PSA layer (adhesive layer) 8 adhesive layer or adhesive layer 9 PSA layer (Adhesive layer) 10: Display device 20: Display panel 30: Display device 40: Touch sensor 50: Window film 200: Organic EL element 210: Substrate 220: First electrode 230: Organic EL layer 240: Second electrode 250: Seal Seabed

Claims (10)

A circularly polarizing plate used for a bendable display device,
A polarizer and at least one or more retardation layers disposed on one side of the polarizer,
A circularly polarizing plate characterized in that the hue of the reflected light obtained before and after bending does not change with respect to the a ^* coordinate axis and the b ^* coordinate axis in the a ^* b ^* chromaticity coordinates.   The circularly polarizing plate according to claim 1, wherein the retardation layer includes a 1⁄4 wavelength plate.   The circularly polarizing plate according to claim 2, wherein the retardation layer includes a half wave plate.   The circularly polarizing plate according to claim 2 or 3, wherein the retardation layer includes a positive C plate.   The circularly polarizing plate according to any one of claims 1 to 4, wherein the retardation layer includes a layer in which a liquid crystal compound is cured.   The circularly polarizing plate according to any one of claims 1 to 5, wherein at least a part of the display device is bent with a curvature radius of 8 mm or less.   The said display apparatus is an organic electroluminescent display apparatus, The circularly-polarizing plate as described in any one of Claims 1-6 characterized by the above-mentioned.   A bendable display device comprising the circularly polarizing plate according to any one of claims 1 to 7 and a bendable display panel. A touch sensor disposed on the side of the circularly polarizing plate facing the display panel;
9. The bendable display device according to claim 8, further comprising: a window film disposed on the side opposite to the side facing the display panel of the circularly polarizing plate.   9. The bendable display device according to claim 8, further comprising a touch sensor disposed on the side opposite to the side facing the display panel of the circularly polarizing plate.

Images