TW202134709A - Optical laminate - Google Patents

Abstract

The present invention provides an optical laminate that is not susceptible to cracking even when bent. The optical laminate 100 comprises, in this order, a front plate 10, a first bonding layer 20, a circularly polarizing plate 60, a second bonding layer 70, and a back plate 80. The circularly polarizing plate 60 has a retardation plate containing a cured product layer of a polymerizable liquid crystal compound, and at least one among the first bonding layer 20 and the second bonding layer 70 is an adhesive layer. The optical laminate 100 further comprises an adhesive part 90 which covers one or both end surfaces 50E of the retardation plate 50 in a cross section along the laminating direction of the optical laminate.

Description

Optical laminate

The present invention relates to an optical laminate, and particularly relates to an optical laminate for flexible displays.

Conventionally, there is known an optical laminate including a front surface plate, a bonding layer, a circular polarizing plate, a bonding layer, and a back plate in this order. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2019-218513

[The problem to be solved by the invention] The inventors conducted studies and found that when such an optical layered body is bent and stored in a bent state, the phase difference plate in the circularly polarizing plate may be prone to cracks.

The present invention was made in view of the above-mentioned problems, and an object thereof is to provide an optical laminate that does not easily cause cracks even when bent. [Means to solve the problem]

The optical laminate of the present invention includes a front surface plate, a first bonding layer, a circularly polarizing plate, a second bonding layer, and a back plate in this order. The circularly polarizing plate has a retardation plate including a cured layer of a polymerizable liquid crystal compound, at least one of the first bonding layer and the second bonding layer is an adhesive layer, and the optical laminate includes An adhesive part which covers one or both end faces of the phase difference plate in a cross section of the optical laminate along the lamination direction.

Here, in the cross section, when the thickness of the adhesive portion in the direction perpendicular to the stacking direction is set to D, 0.5 mm≦D≦5 mm can be satisfied.

In addition, the thickness of the cured product layer of the polymerizable liquid crystal compound may be 5 μm or less.

In addition, the retardation plate may have a positive C plate, and the positive C plate may have a cured layer of the polymerizable liquid crystal compound.

In addition, in the cross section, the adhesive portion may cover the entire one or both end surfaces of the circular polarizing plate.

In addition, in the cross-section, one end surface of the front surface plate, one end surface of the adhesive layer, and one end surface of the back plate may be aligned with the stacking direction of the end surface of the circular polarizing plate. The direction of the intersection is more prominent.

In addition, in the cross-section, the two end surfaces of the front surface plate, the two end surfaces of the adhesive layer, and the two end surfaces of the back plate may be located at a greater distance than the two end surfaces of the circular polarizing plate. It is more prominent in the direction orthogonal to the stacking direction.

In addition, both the first bonding layer and the second bonding layer may be adhesive layers.

In addition, the optical laminate may be used for flexible displays. [Effects of the invention]

According to the present invention, there is provided an optical laminate that does not easily generate cracks even when bent.

(First Embodiment) ＜Optical laminated body＞ FIG. 1 is a schematic cross-sectional view of the optical laminate according to the first embodiment of the present invention. The optical laminate 100 shown in FIG. 1 is sequentially laminated with a front surface plate 10, a first adhesive layer 20A (first bonding layer 20), a circular polarizing plate 60, and a second adhesive layer 70A (second bonding layer). 70) And the back panel 80. Furthermore, the Z direction is the stacking direction, and +Z is the visual recognition side, and the person catches the light emitted in the +Z direction. In addition, the X direction is a bending axis, and the Y direction is a direction perpendicular to the bending axis.

(Front surface plate 10) As long as the front surface plate 10 is a plate-shaped body that can transmit light and can be bent, the material and thickness are not limited, and may include only one layer, or two or more layers. Examples thereof include plate-shaped bodies made of resin (for example, resin plates, resin sheets, resin films, etc.), plate-shaped bodies made of glass (for example, glass plates, glass films, etc.), plate-shaped bodies made of resin, and glass The laminated body of the plate-shaped body. The front surface plate may be the layer constituting the most surface of the display device.

The thickness of the front surface plate 10 may be, for example, 10 μm or more and 1,000 μm or less, preferably 20 μm or more and 500 μm or less, and more preferably 30 μm or more and 300 μm or less.

In the case where the front surface plate 10 is a resin-made plate-shaped body, the resin-made plate-shaped body is not limited as long as it can transmit light. Examples of resins include films containing the following polymers: triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, acrylic cellulose, butyl cellulose, acetyl propylene fiber Element, polyester, polystyrene, polyamide, polyetherimide, poly(meth)acrylic acid, polyimide, polyether stubble, poly stubble, polyethylene, polypropylene, polymethylpentene, Polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether agglomerate, polymethyl methacrylate, polyethylene terephthalate, poly Butylene terephthalate, polyethylene naphthalate, polycarbonate, polyamide imide, etc. The polymer can be used alone or in combination of two or more. From the viewpoint of improving strength and transparency, a resin film formed of a polymer such as polyimide, polyimide, and polyimide is preferred. The thickness of the resin plate-shaped body may be, for example, 10 μm or more and 1,000 μm or less, preferably 20 μm or more and 500 μm or less, more preferably 30 μm or more and 300 μm or less, and may be 100 μm or less.

As shown in FIG. 2, the front surface plate 10 may have a structure in which a hard coat layer 12 is provided on at least one surface of the base film 14 to further increase the hardness. As the base film 14, a plate-shaped body made of the above-mentioned resin can be used. The hard coat layer 12 may be formed on one surface of the base film 14 (for example, the visually recognizable side, that is, the side opposite to the first adhesive layer), or may be formed on both surfaces. By providing the hard coat layer 12, the front surface board 10 with improved hardness and scratch resistance can be manufactured. The hard coat layer 12 is, for example, a cured layer of ultraviolet curable resin. Examples of ultraviolet curable resins include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, epoxy resins, and the like. In order to increase the hardness, the hard coat layer 12 may contain additives. The additives are not limited, and examples include inorganic fine particles, organic fine particles, or mixtures of these.

When the front surface plate 10 is a glass plate, it is preferable to use tempered glass for display as the glass plate. The thickness of the glass plate can be, for example, 10 μm or more and 1,000 μm or less. By using a glass plate, the front surface plate 10 having excellent mechanical strength and surface hardness can be constructed.

In the case of using the optical laminate 100 for a display device, the front surface plate 10 may have a function as a window film in the display device. The front surface plate 10 may also have a function as a touch sensor, a blue light blocking function, a viewing angle adjustment function, and the like.

(The first adhesive layer 20A (the first bonding layer 20)) As shown in FIG. 1, the first adhesive layer 20A is disposed between the front surface plate 10 and the circular polarizing plate 60 to fix them.

The so-called adhesive is a pressure-sensitive adhesive, which presents a soft solid (viscoelastic) state in a temperature region near room temperature (for example, 25°C), and has the property of being easily adhered to an adherend by pressure.

The main components of the first adhesive layer 20A are not particularly limited. For example, they may be (meth)acrylic polymers, urethane-based polymers, polyester-based polymers, silicone-based polymers, and polyvinyl ether. -Based polymers, rubber-based polymers and other polymers. In this specification, the main component refers to a component containing 50% by mass or more in the total solid content of the layer. In addition, the "(meth)acrylic resin" in this specification means at least one selected from the group consisting of acrylic resins and methacrylic resins.

As the (meth)acrylic polymer, for example, butyl (meth)acrylate, ethyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, and (meth)acrylate are preferably used. Base) lauryl acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate and the like (methyl) ) Polymers or copolymers in which one or two or more of acrylates are used as monomers. The base polymer is preferably copolymerized with a polar monomer. Examples of polar monomers include (meth)acrylic acid, 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth) Monoacrylamide, N,N-dimethylamino ethyl (meth)acrylate, glycidyl (meth)acrylate and the like having carboxyl groups, hydroxyl groups, amide groups, amino groups, epoxy groups, etc. body.

The adhesive may only contain the base polymer, but usually contains a crosslinking agent. Examples of the crosslinking agent include: a metal ion having a valence of 2 or higher and forming a metal carboxylate with a carboxyl group; a polyamine compound forming an amide bond with a carboxyl group; a polyepoxy compound or Polyols, which form ester bonds with carboxyl groups; polyisocyanate compounds, which form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferred.

The first adhesive layer 20A may be an active energy ray hardening type that is hardened by active energy rays such as ultraviolet rays or electron rays, or a thermal hardening type that is hardened by heating. In this case, it still has adhesiveness before the active energy ray is irradiated and can be adhered closely to the film and other adherends, and the active energy ray is irradiated to harden and the adhesion can be adjusted. The active energy ray-curable adhesive contains a raw material polymer and a cross-linking agent, as well as an active energy ray polymerizable compound. In addition, if necessary, a photopolymerization initiator, photosensitizer, etc. are also contained.

In addition to polymers, the first adhesive layer 20A may also contain solvents; adhesion imparting agents, softeners, fillers (metal powder or other inorganic powders, etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, and disinfectants. Additives such as foaming agents, preservatives, photopolymerization initiators, etc.

The thickness of the first adhesive layer 20A is not particularly limited. It is preferably 2 μm or more, may be 15 μm or more, may be 20 μm or more, or may be 25 μm or more, and is usually 200 μm or less, and may be 100 μm or less, but also 50 μm or less.

The storage elastic coefficient of the first adhesive layer 20A at 25°C is preferably 1×10 ⁶ Pa (1 MPa) or less, more preferably 5×10 ⁵ Pa (0.5 MPa) or less, and still more ^{preferably 3×10 5} Pa (0.3 MPa) or less. If the storage elasticity coefficient is 1×10 ⁶ Pa (1 MPa) or less, it is less likely to produce bubbles due to bending, or display unevenness is less likely to occur, so it is preferable. In addition, the storage elastic coefficient is preferably 1×10 ⁴ Pa (0.01 MPa) or more, more preferably 2×10 ⁴ Pa (0.02 MPa) or more, and still ^{more preferably 3×10 4} Pa (0.03 Mpa) or more. If the storage elasticity coefficient is 1×10 ⁴ Pa (0.01 MPa) or more, the adhesive tends to be difficult to adhere to other parts during manufacturing operations, so it is preferable. In addition, the storage elastic coefficient of the adhesive at 80°C is preferably 5×10 ⁵ Pa (0.5 MPa) or less, more preferably 3×10 ⁵ Pa (0.3 MPa) or less, and still more ^{preferably 1×10 5} Pa (0.1 MPa) MPa) or less, particularly preferably 5×10 ⁴ Pa (0.05 MPa) or less, and particularly preferably 3×10 ⁴ Pa (0.03 MPa) or less. When the storage elastic coefficient at 80°C is 5×10 ⁵ Pa (0.5 MPa) or less, since the fluidity during heating operation is good, there is a tendency to suppress the generation of bubbles, which is preferable.

The storage elasticity coefficient can be measured using a viscoelasticity measuring device (MCR-301, Anton Paar). It is possible to laminate multiple adhesive layers with a thickness of 150 μm and join them to the glass plate, and in the state of being bonded to the measuring wafer, in the temperature range of -20°C to 100°C, at a frequency of 1.0 Hz, a deformation amount of 1%, The measurement is performed under the condition of a temperature increase rate of 5°C/min.

The loss tangent of the first adhesive layer 20A at 25° C. can be, for example, 0.7 or less, preferably less than 0.5, and more preferably 0.3 or less.

(Circular Polarizing Plate 60) As shown in FIG. 1, the circular polarizing plate 60 has a linear polarizing plate 30, a bonding layer 40, and a retardation plate 50 in this order from the front surface plate 10 side (visible side). The linear polarizing plate 30 is arranged closer to the front surface plate 10 than the retardation plate 50 is. The bonding layer 40 fixes the linear polarizing plate 30 and the retardation plate 50. The circularly polarizing plate may not have the bonding layer 40.

(Straight Polarizing Plate) The linear polarizing plate 30 has a function of selectively transmitting linearly polarized light in one direction from non-polarized light such as natural light. As shown in FIG. 3, the linear polarizer 30 has a polarizer layer 34, and may further have a protective layer 32 and a protective layer 36 provided on one or both sides of the polarizer layer 34.

The polarizer layer 34 may be a stretched film to which a dichroic dye is adsorbed, or it may be a cured product containing a polymerizable liquid crystal compound and a dichroic dye, and the dichroic dye is dispersed in the cured product of the polymerizable liquid crystal compound The alignment of the liquid crystal layer. The dichroic dye refers to a dye having a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction of the molecule.

(When the polarizer layer is a stretched film) Stretched films adsorbing dichroic pigments are usually produced through the following steps: a step of uniaxially stretching a polyvinyl alcohol-based resin film; by dyeing the polyvinyl alcohol-based resin film with dichroic pigments such as iodine The step of adsorbing the dichroic dye; the step of treating the polyvinyl alcohol resin film on which the dichroic dye is adsorbed with an aqueous solution of boric acid; and the step of washing with water after the treatment with the aqueous solution of boric acid. The obtained polarizer layer as a stretched film can be directly used as a linear polarizing plate, and it can also be used as a linear polarizing plate having a protective layer formed on one or both sides. The thickness of the polarizer layer thus obtained is preferably 2 μm to 40 μm.

The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and other monomers copolymerizable therewith is used. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is generally about 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified. For example, polyvinyl formaldehyde or polyvinyl acetal modified with aldehydes may also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 to 10,000 or so, preferably in the range of 1,500 to 5,000.

The film thickness of the polyvinyl alcohol-based resin film before stretching can be set to, for example, about 10 μm to 150 μm.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be carried out before dyeing with a dichroic dye, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before the boric acid treatment or may be performed during the boric acid treatment. In addition, it is also possible to perform uniaxial stretching in the multiple stages described above. In the case of uniaxial stretching, uniaxial stretching can be performed between rolls with different peripheral speeds, or a heated roll can be used for uniaxial stretching. In addition, uniaxial stretching can be either dry stretching or wet stretching, where dry stretching is performed in the atmosphere, and wet stretching is in a state where the polyvinyl alcohol resin film is swelled with a solvent. Stretching under. The stretching ratio is usually about 3 to 8 times.

The thickness of a linear polarizer having a stretched film as a polarizer layer and including a protective layer on one or both sides may be, for example, 1 μm or more and 100 μm or less, 5 μm or more, or 7 μm or more, and , Can be 70 μm or less, 50 μm or less, 20 μm or less, or 10 μm or less.

The materials of the protective layer 32 and the protective layer 36 provided on one or both sides of the polarizer layer 34 are not particularly limited. Examples include cyclic polyolefin resins; including triacetyl cellulose and diacetyl cellulose. Cellulose acetate-based resins such as resins; polyester-based resins containing resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; poly Carbonate resins; (meth)acrylic resins; polypropylene resins and other resins known in the art. From the viewpoint of thinning, the thickness of the protective layer is usually 100 μm or less, preferably 60 μm or less, more preferably 30 μm or less, and usually 5 μm or more, preferably 10 μm or more. The protective layer may be a film, and the film-like protective layer may have a phase difference. When the protective layer is a film, the polarizer layer and the protective layer can be laminated via an adhesive layer or an adhesive layer. The adhesive layer or the adhesive layer can be formed using the adhesive composition or the adhesive composition described above.

(When the polarizer layer is a liquid crystal layer) The polymerizable liquid crystal compound used for forming the liquid crystal layer is a compound having a polymerizable reactive group and exhibiting liquid crystallinity. The polymerizable reactive group is a group that participates in the polymerization reaction, and is preferably a photopolymerizable reactive group. The photopolymerizable reactive group refers to a group that can participate in a polymerization reaction by a living radical or acid generated from a photopolymerization initiator. Examples of photopolymerizable functional groups include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloxy groups, methacryloxy groups, and oxiranes. Group, oxetanyl, etc. Among them, propyleneoxy, methacryloxy, vinyloxy, oxepanyl and oxetanyl groups are preferred, and propyleneoxy is more preferred. The type of the polymerizable liquid crystal compound is not particularly limited, and rod-shaped liquid crystal compounds, discotic liquid crystal compounds, and mixtures thereof can be used. The liquid crystallinity of the polymerizable liquid crystal compound may be thermotropic liquid crystal or lyotropic liquid crystal. As the phase sequence structure, it may be nematic liquid crystal or smectic liquid crystal.

The dichroic dye used for the polarizer layer using the liquid crystal layer is preferably one having an absorption maximum wavelength (λMAX) in a wavelength range of 300 nm to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes. Among them, azo dyes are preferred. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrasazo dyes, and stilbene azo dyes, and bisazo dyes and trisazo dyes are preferred. The dichroic dye may be singly or in combination of two or more, preferably three or more in combination. In particular, it is more preferable to combine three or more azo compounds. More than one dichroic dye may have a reactive group. One or more dichroic pigments can show liquid crystallinity.

The polarizer layer using the liquid crystal layer can be formed by, for example, coating a polarizing layer forming composition containing a polymerizable liquid crystal compound and a dichroic dye on an alignment film formed on a substrate, and polymerizing the polymerizable liquid crystal compound to make it Hardened and formed. Alternatively, the composition for forming a polarizer layer may be coated on a substrate to form a coating film, and the coating film may be stretched together with the substrate layer to form a polarizer layer. The substrate used to form the polarizer layer can also be used as a protective layer for the polarizer layer. As the base material, a resin film is exemplified, for example, a film molded using the material forming the protective layer is exemplified.

As a composition for forming a polarizer layer containing a polymerizable liquid crystal compound and a dichroic dye, and a method for producing a polarizer layer using the composition, Japanese Patent Laid-Open No. 2013-37353 and Japanese Patent Laid-Open 2013 can be exemplified -33249, Japanese Patent Laid-Open No. 2017-83843, etc. In addition to the polymerizable liquid crystal compound and the dichroic dye, the composition for forming a polarizer layer may further contain additives such as a solvent, a polymerization initiator, a crosslinking agent, a leveling agent, an antioxidant, a plasticizer, and a sensitizer. Only one kind of these components may be used, respectively, or two or more kinds may be used in combination.

The polymerization initiator that may be contained in the composition for forming a polarizer layer is a compound that can initiate a polymerization reaction of a polymerizable liquid crystal compound, and a photopolymerizable initiator is preferred in terms of being capable of initiating a polymerization reaction under lower temperature conditions. Specifically, photopolymerization initiators that can generate active radicals or acids by the action of light are exemplified. Among them, photopolymerization initiators that can generate free radicals by the action of light are preferred. The content of the polymerization initiator is preferably 1 part by mass to 10 parts by mass, and more preferably 3 parts by mass to 8 parts by mass relative to 100 parts by mass of the total amount of the polymerizable liquid crystal compound. If it is within this range, the reaction of the polymerizable group proceeds sufficiently, and it is easy to stabilize the alignment state of the liquid crystal compound.

The thickness of the polarizer layer using the liquid crystal layer is not particularly limited, but is preferably 20 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, and may also be 3 μm or less. Although there is no lower limit for the thickness, it may be 0.5 μm or more.

As shown in FIG. 3, the polarizer layer 34 using a liquid crystal layer may have a protective layer 32 and a protective layer 36 also called an overcoat/anti-diffusion layer on one or both sides of the polarizer layer 34. The outer coating/anti-diffusion layer can be provided for the purpose of protecting the linear polarizing layer. The protective layer can be formed by coating a protective layer forming material (composition) on a linear polarizing layer, or coating a protective layer forming material on a substrate to be peeled later, and forming an alignment film and a linear polarizing layer on the protective layer. To form. Examples of the material for forming the protective layer include photocurable resins, water-soluble polymers, and the like, and (meth)acrylic resins or polyvinyl alcohol resins can be used. The thickness of the protective layer is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, may also be 5 μm or less, and may be 0.05 μm or more, or may be 0.5 μm or more. The thickness of the polarizer layer 34 using the liquid crystal layer and the linear polarizer 30 including the protective layer 32 and the protective layer 36 on one or both sides thereof can be set to 1.0 μm to 30 μm.

(Lamination layer 40) The bonding layer 40 is not particularly limited, and may be the same adhesive layer as the first adhesive layer 20A, or an adhesive layer. The thickness can be set from 3.0 μm to 50 μm.

When the bonding layer is an adhesive layer, the adhesive composition for forming the adhesive layer is not particularly limited, and examples thereof include a water-based adhesive, an active energy ray-curable adhesive, and the like.

As the water-based adhesive, for example, a polyvinyl alcohol-based resin aqueous solution, an aqueous two-component urethane-based emulsion adhesive, and the like can be cited. The active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays, and examples thereof include adhesives containing polymerizable compounds and photopolymerizable initiators, adhesives containing photoreactive resins, Adhesives containing binder resins and photoreactive crosslinking agents, etc. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth)acrylic monomers, and photocurable urethane monomers, or sources. Oligomers from these monomers, etc. Examples of the photopolymerization initiator include those containing active species such as neutral radicals, anionic radicals, and cationic radicals by irradiating active energy rays such as ultraviolet rays.

(Phase Difference Plate 50) The phase difference plate 50 includes at least a λ/4 plate. The λ/4 plate is a film that gives a phase difference of λ/4 in a direction (in-plane direction of the film) orthogonal to the traveling direction of incident light. The angle formed by the slow axis of the λ/4 plate and the absorption axis of the linear polarizer 30 may be 45°±10°. The λ/4 plate may also be a λ/4 plate with reverse wavelength dispersion.

The λ/4 plate may also be a stretched retardation plate manufactured by stretching a polymer film such as a cellulose-based film, an olefin-based film, or a polycarbonate-based film. If necessary, it can also contain retardation adjusters, plasticizers, ultraviolet absorbers, infrared absorbers, coloring agents such as pigments or dyes, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, anti- Electrostatic agents, antioxidants, lubricants, solvents, etc. The thickness of the stretched λ/4-position plate may be 100 μm or less, preferably 1 μm-50 μm. When the thickness exceeds 100 μm, flexibility may decrease.

In addition, as another example of the λ/4 plate, a liquid crystal coating type λ/4 plate formed by applying a liquid crystal composition may also be used. The liquid crystal composition contains a liquid crystal compound having the property of displaying liquid crystal states such as nematic, cholesteric, and smectic. Any one compound containing a liquid crystal compound in the liquid crystal composition has a polymerizable functional group, that is, it is a polymerizable liquid crystal compound. The liquid crystal composition may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The liquid crystal coating type λ/4 plate can be manufactured by coating a liquid crystal composition containing a polymerizable liquid crystal compound on an alignment film provided on a substrate and hardening to form a liquid crystal retardation layer, and may include a polymerizable liquid crystal compound Hardened layer and alignment film. That is, the liquid crystal coating type λ/4 plate can be made thinner than the stretched λ/4 plate. The thickness of the liquid crystal coating type λ/4 plate is 0.5 μm-10 μm, and preferably 1 μm-5 μm. The liquid crystal coating type λ/4 plate may be peeled from the base material and transferred to the laminate, or the base material may be directly laminated. The base material is also preferably used as a transparent base material for a protective film, a phase difference plate, and a front surface plate.

Generally speaking, the shorter the wavelength, the greater the birefringence, and the longer the wavelength, the smaller the birefringence. In this case, the retardation of λ/4 cannot be achieved in the entire visible light region, so it is often designed to have a retardation value of λ/4 near the wavelength of 560 nm where the visual sensitivity is high, and the in-plane retardation value is 100 nm～ 180 nm, preferably 130 nm to 150 nm. It is preferable to use a λ/4 plate having reverse wavelength dispersion properties of a material having a birefringence wavelength dispersion characteristic which is opposite to that of usual, since the visibility becomes better. As such a material, it is preferable to use the materials described in Japanese Patent Laid-Open No. 2007-232873 and the like in the case of a stretch-type retardation plate, and it is also preferable to use the Japanese Patent Special in the case of a liquid crystal coating type retardation plate. Open the materials described in the 2010-30979 Bulletin.

As shown in (a) of FIG. 4, the phase difference plate 50 may include only the λ/4 plate 52.

As shown in FIGS. 4(b) to 4(d), in addition to the λ/4 plate 52, the phase difference plate 50 may have one or more plates that give other phase differences. Examples of plates to which other phase differences are provided are the λ/2 plate 58 and the positive C plate 56.

The λ/2 plate is a film that gives a phase difference of λ/2 in a direction (in-plane direction of the film) orthogonal to the traveling direction of incident light. The λ/2 plate can also be manufactured by the same material method as the λ/4 plate. It is known that a wide-band λ/4 phase difference plate is obtained by combining a λ/2 plate on a λ/4 plate (Japanese Patent Laid-Open No. 10-90521). The thickness of the λ/2 plate is 0.5 μm-10 μm, and preferably 1 μm-5 μm.

The positive C plate is a film that satisfies nx≒ny<nz. "≒" includes not only the situation where the two are exactly the same, but also the situation where the two are substantially the same. The so-called "substantially the same" means that, for example, (nx-ny)×d (where d is the thickness of the film) is 0 nm to 10 nm, preferably 0 nm to 5 nm, which is also included in "nx≒ny" .

When a positive C plate is added to the λ/4 plate, the visibility in the oblique direction can be improved (refer to Japanese Patent Laid-Open No. 2014-224837). The positive C plate may be a liquid crystal coating type retardation plate or a stretched type retardation plate. The phase difference in the thickness direction is from -200 nm to 20 nm, preferably from -140 nm to -40 nm. The thickness of the positive C plate is 0.5 μm-10 μm, preferably 1 μm-5 μm.

When the phase difference plate 50 has two or more phase difference plates, it may have a bonding layer 54 for bonding the phase difference plates (for example, a λ/4 plate and a positive C plate) to each other. As the bonding layer, it may be the aforementioned adhesive or adhesive. The thickness of the bonding layer can be set to 1.0 μm to 10.0 μm.

When the phase difference plate 50 includes a positive C plate, as shown in FIG. 4(b), it may include a λ/4 plate 52, a bonding layer 54, and a positive C plate 56 in order from the linear polarizing plate 30 side. As shown in FIG. 4(c), the positive C plate 56, the bonding layer 54, and the λ/4 plate 52 may be included in this order from the linear polarizing plate 30 side.

In the case where the retardation plate 50 includes a λ/4 plate and a λ/2 plate, as shown in FIG. 4(d), it may include a λ/2 plate 58 and a bonding layer 54 in order from the linear polarizing plate 30 side. , And λ/4 plate 52. The angle formed by the slow axis of the λ/4 plate 52 and the slow axis of the λ/2 plate 58 may be 60°±10°.

As described above, the plate for providing each phase difference may include a stretched film, or may include a layer formed by curing a polymerizable liquid crystal compound. The retardation-imparting plate may further include an alignment film or a base film.

Among them, at least one of the retardation plates 50 that imparts a retardation includes a cured layer of a polymerizable liquid crystal compound. Preferably, the thickness of the cured product layer is 5 μm or less. Although the thickness has no lower limit, it can be 0.5 μm and 1 μm, for example. The phase difference plate including this layer is prone to cracks when bent, and it is easy to exhibit the effects of the present invention.

For example, as shown in FIG. 4(a), in the case where the retardation plate 50 is composed of only the λ/4 plate 52, the λ/4 plate 52 has a cured layer of a polymerizable liquid crystal compound, and the cured layer is preferably The thickness of the material layer is 5 μm or less.

On the one hand, as shown in FIGS. 4(b) to 4(d), when the retardation plate 50 has a plurality of retardation-imparting plates, at least one retardation-imparting plate has a polymerizable liquid crystal compound Hardened layer. In this case, it is preferable that the thickness of the hardened material layer is 5 μm or less. Of course, the plurality of retardation layers of the retardation plate 50 may each have a cured layer of a polymerizable liquid crystal compound, and the thickness of each cured layer may be 5 μm or less.

In particular, the phase difference plate 50 preferably has a positive C plate 56 which includes a cured layer of a polymerizable liquid crystal compound. In particular, if the thickness of the cured layer is 5 μm or less, the effect may sometimes change. high.

In addition, the phase difference plate 50 may have an overcoat that protects the surface of the plate to which each phase difference is provided.

The thickness of the phase difference plate 50 is not particularly limited. For example, it can be 1 μm or more and 50 μm or less.

The circular polarizing plate 60 can suppress the emission of reflected light of external light incident from the front surface plate 10, and therefore, can provide the optical laminate 100 with a function as an anti-reflection film.

(The second adhesive layer 70A (the second bonding layer 70)) The second adhesive layer 70A is provided on the surface on the opposite side of the first adhesive layer 20A in the circular polarizing plate 60, that is, on the surface of the phase difference plate 50.

The material of the second adhesive layer 70A is not particularly limited, and the same material as that of the first adhesive layer 20A can be used, and the thickness can also be appropriately set within the same range. In the first adhesive layer and the second adhesive layer, the adhesives may be the same or different from each other.

(Back panel) As the back plate 80, a plate-shaped body capable of transmitting light, a structural member used in a normal display device, or the like can be used.

The thickness of the back plate 80 may be, for example, 5 μm or more and 2,000 μm or less, preferably 10 μm or more and 1,000 μm or less, and more preferably 15 μm or more and 500 μm or less.

The plate-shaped body used for the back panel 80 may include only one layer, or may include two or more layers, and the plate-shaped body exemplified in the front panel 10 can be used.

Examples of constituent members used in a normal display device used for the back panel 80 include touch sensor panels, barrier films, electroluminescence (EL) panels, and the like.

The EL panel may be an organic EL panel. For example, as described in Japanese Patent No. 4601463, it may have a transparent substrate/transparent electrode layer/organic EL layer/electrode which may contain a gas barrier layer in order from the side of the second adhesive layer 70A. Floor. The structure of the organic EL layer can be formed into, for example, the structure listed in Japanese Patent No. 4707996.

An example of the barrier film may be a film having a base material and an inorganic material layer provided on one or both surfaces of the base material as described in Japanese Patent No. 4976116.

(Touch sensor panel) As the touch sensor panel, as long as it is a sensor that can detect the position being touched, the detection method is not limited. Examples include: resistive film method, electrostatic capacitance coupling method, optical sensor method, ultrasonic wave Touch sensor panels such as the method, electromagnetic induction coupling method, surface acoustic wave method, etc. In terms of low cost, it is preferable to use a touch sensor panel of a resistive film method or an electrostatic capacitance coupling method.

An example of a touch sensor panel of a resistive film method may include a pair of substrates arranged to face each other, an insulating spacer sandwiched between the pair of substrates, and a front surface on the inner side of each substrate as a resistor. Film set of transparent conductive film. In an image display device provided with a touch sensor panel of a resistive film type, when the surface of the front panel 10 is touched, the opposing resistive films are short-circuited, and current flows through the resistive films. The touch position detection circuit detects the voltage change at this time, thereby detecting the touched position.

An example of the touch sensor panel of the electrostatic capacitance coupling method may include a substrate and a transparent electrode for position detection provided on the surface of the substrate. In the image display device provided with the touch sensor panel of the electrostatic capacitance coupling method, when the surface of the front surface plate 10 is touched, at the touched point, the transparent electrode is grounded via the electrostatic capacitance of the human body. The touch position detection circuit detects the grounding of the transparent electrode, thereby detecting the touched position.

The thickness of the touch sensor panel may be, for example, 5 μm or more and 2,000 μm or less, or may be 5 μm or more and 100 μm or less.

FIG. 5 is a schematic cross-sectional view schematically showing an example of a touch sensor panel (rear plate 80) of an electrostatic capacitance method.

The touch sensor panel (back panel 80) shown in FIG. 5 has a base layer 130 and a touch sensor layer 120. The base layer 130 has a support layer 121, a bonding layer 135, and a base layer 131 in order from the touch sensor layer 120 side.

The base material layer 131 is provided for imparting strength and the like to the touch sensor layer 120, and may be formed of a resin material.

The bonding layer 135 is a layer for bonding the base layer 131 and the support layer 121, and may be an adhesive layer or an adhesive layer.

The support layer 121 has a separation layer 122, a protection layer 123, and a refractive index adjustment layer 124 in order from the base layer 131 side, and supports the touch sensor layer 120 and the first insulating layer 111.

The separation layer 122 is a layer used as a base material of the touch sensor layer 120 in the steps of manufacturing the touch sensor layer 120 and the first insulating layer 111. The separation layer 122 may be a layer of inorganic materials such as silicon oxide or various resin materials.

The protective layer 123 is a layer that covers the patterned conductive layer or the first conductive layer 127 together with the separation layer 122 for protection or electrical insulation, and may be formed of an insulating material.

The refractive index adjustment layer 124 is a layer that provides a predetermined refractive index to the touch sensor panel. The material of the refractive index adjustment layer 124 is, for example, a resin material, a resin material containing a pigment, or a metal compound.

Furthermore, the support layer 121 may have any one or more of the separation layer 122, the protective layer 123, and the refractive index adjustment layer 124.

(Touch sensor layer 120) The touch sensor layer 120 has a first conductive layer 127, a second conductive layer 128, a first insulating layer 111, and a second insulating layer 129.

A plurality of first conductive layers 127 are provided on the base layer 130. The second insulating layer 129 covers the basic layer 130 and the first conductive layer 127. A plurality of second conductive layers 128 are provided on the second insulating layer 129. The second insulating layer 129 has an opening connecting the first conductive layer 127 and the second conductive layer 128, and a through hole b for electrically connecting the first conductive layer 127 and the second conductive layer 128 is provided in the opening.

(Pattern conductive layer (first conductive layer 127 and second conductive layer 128)) As shown in FIG. 6, the first conductive layer 127 includes polygonal unit patterns 127a and unit patterns 127b alternately arranged in an oblique direction (oblique grid), and a connection that connects the unit patterns 127a to each other along the horizontal direction in FIG.部127c. The second conductive layer 128 includes a connecting portion 128c that connects the unit patterns 127b to each other along the longitudinal direction in FIG. 6. The unit pattern 127a and the unit pattern 127b are separately arranged as shown in the blank (the part without diagonal lines) in FIG. 6 and are also electrically insulated. In this embodiment, each conductive layer is formed in a pattern so that the first conductive layer 127 serves as a touch electrode and the second conductive layer 128 serves as a part of the bridge wiring. The material of the pattern conductive layer and the through-hole portion b is, for example, transparent conductive and a metal material.

As described above, the patterned conductive layer may have a multi-layer structure or a single-layer structure. The shape of the patterned conductive layer is not particularly limited. For example, it can be formed in a polygonal shape such as a circle, an ellipse, a quadrilateral, or a hexagon.

(The first insulating layer and the second insulating layer) The second insulating layer 129 is disposed between the first conductive layer 127 and the second conductive layer 128 to electrically insulate the first conductive layer 127 from the second conductive layer 128. The first insulating layer 111 is provided to cover at least the surface of the touch sensor layer 120 on the side opposite to the base layer 130 side. The material of the first insulating layer and the second insulating layer 129 may be, for example, an electrically insulating material.

(Connect wiring) The touch sensor panel may have connection wiring 125. The connection wiring connects the patterned conductive layer with an external circuit or a driving circuit. Examples of the material forming the connection wiring 125 are a transparent conductive substance and a metal material.

(End structure of optical laminate 100) In Fig. 1, the Z direction is the stacking direction, +Z is the visual recognition side, and the person captures the light emitted in the +Z direction.

As shown in FIG. 1, in one cross section of the optical layered body 100 of the present embodiment along the layering direction, the end surface 50E of the phase difference plate 50 is covered with the adhesive portion 90.

It is also preferable that in the cross section, the adhesive portion 90 not only covers the retardation plate 50, but also covers the entire end surface 60E of the circular polarizing plate 60, that is, the linear polarizing plate 30, the bonding layer 40, and the retardation plate 50. .

In the cross section, it is preferable that the two end faces 50E (60E) of the phase difference plate 50 or the circular polarizer 60 are covered by the adhesive part 90, but any one end face 50E (60E) may be covered by the adhesive part 90 .

One or both end faces 50E (60E) of the phase difference plate 50 or the circular polarizer 60 should just have the adhesive part 90 in a certain cross section parallel to the stacking direction (for example, a cross section parallel to the bending axis). By setting the direction perpendicular to the stacking direction (the horizontal direction in FIG. 1) as the bending axis in this cross section, it becomes easy to exert the effect of the present invention. For example, when the planar shape of the optical laminate is rectangular and the short sides are curved so that the short sides face each other, it is preferable that at least the central portion in the long side direction of the two end faces 50E (60E) corresponding to the pair of long sides It is covered by the adhesive part 90.

It is also preferable that the phase difference plate 50 or the circular polarizing plate 60 has an adhesive part 90 in the entire in-plane direction of each end surface 50E (60E).

It is also preferable that the phase difference plate 50 or the circular polarizing plate 60 has an adhesive part 90 in the entire in-plane direction with respect to the two end faces 50E (60E) facing each other.

Furthermore, in the case where the phase difference plate 50 and the circular polarizer 60 have four or more end faces, the end faces other than the two opposite end faces 50E (60E) may be covered by the adhesive, or may not be covered by the adhesive. .

However, the retardation plate 50 or the circular polarizing plate 60 may have the adhesive part 90 on all the end surfaces. For example, when the planar shape of the circular polarizing plate 60 is rectangular, the adhesive portion 90 may be provided on all four end surfaces.

In the cross section, when the thickness of the adhesive portion 90 in the direction perpendicular to the layering direction is set to D, it is preferable to satisfy 0.5 mm≦D≦5 mm. D is preferably 1 mm or more.

In the cross section, one or two end surfaces 10E of the front surface plate 10, one or two end surfaces 20AE of the first adhesive layer 20A, one or two end surfaces 70AE of the second adhesive layer 70A, and the back plate 80 Preferably, one or two end surfaces 80E of the phase difference plate 50 or the one end surface 50E (60E) of the circular polarizer 60 respectively protrude in a direction orthogonal to the stacking direction. Thereby, the first adhesive layer 20A, the second adhesive layer 70A, and the adhesive portion 90 can be easily integrated.

Regarding the relationship between the width 60W between the end faces 60E of the circular polarizing plate 60, the width 10W between the end faces of the front surface plate 10, and the width 80W between the end faces of the back plate 80, 80W-60W and 10W-60W are respectively referred to 2 times of the above D, that is, it may be 1 mm to 10 mm, or 2 mm to 10 mm.

Each end surface 20AE of the first adhesive layer 20A, each end surface 90E of the adhesive portion 90, and each end surface 70AE of the second adhesive layer 70A may be more than each end surface 10E of the front surface plate 10 and each end surface 80E of the back plate 80 It can be on the inner side, on the same surface, or on the outer side, preferably on the same surface or on the outer side. The protrusion amount of the end face 20AE, the end face 90E, and the end face 70AE can be set to 5 mm or less.

The material of the adhesive part 90 can be selected from the materials of the adhesive layer described above. The adhesive part 90 may be the same adhesive as the adhesive of the first adhesive layer 20A or the second adhesive layer 70A.

The thickness of the optical laminate 100 varies depending on the functions required of the laminate and the purpose of the laminate, so it is not particularly limited, but is, for example, 50 μm or more and 1,000 μm or less, preferably 100 μm or more and 500 μm or less .

The planar shape of the optical laminate 100 may be, for example, a square shape, preferably a square shape having long sides and short sides, and more preferably a rectangular shape. When the shape of the surface direction of the optical layered body 100 is a rectangle, the length of the long side may be, for example, 10 mm or more and 1400 mm or less, and preferably 50 mm or more and 600 mm or less. The length of the short side is, for example, 5 mm or more and 800 mm or less, preferably 30 mm or more and 500 mm or less, and more preferably 50 mm or more and 300 mm or less.

When the planar shape of the optical laminate 100 is a square shape, the length of each side of the front surface plate 10 and the back plate 80 may be the same, and it is preferable that the positions of the end surfaces of the front surface plate 10 and the back plate 80 are viewed from the thickness direction Located in the same location. When the planar shape of the optical laminate 100 is a square shape, the positions of the end faces of the first adhesive layer 20A and the second adhesive layer 70A may be the same as the positions of the end faces of the front surface plate 10 and the back plate 80, or It can be located further inside.

As in the present embodiment, in the retardation plate 50 containing a cured layer of a polymerizable liquid crystal compound, when the end surface 50E perpendicular to the bending axis is covered by the adhesive portion 90, the flexibility of the optical laminate 100 is improved. The reason for this is not clear, but it is believed that the cured layer of the polymerizable liquid crystal compound is prone to cracks when stored in a curved state, but when the end surface is covered by the adhesive part, the crack from the end surface can be suppressed even in the curved state Generation and expansion.

(Second Embodiment) Next, the optical laminate 100 according to the second embodiment of the present invention will be described with reference to FIG. 7. After the second embodiment, only the differences from the first embodiment will be described, and the description of the overlapping parts will be omitted.

The optical laminate 100 of this embodiment is different from the first embodiment in that an adhesive layer 20B is used instead of the first adhesive layer 20A. As the adhesive agent, the adhesive agent exemplified in the bonding layer 40 described above can be used. The thickness of the adhesive layer 20B can be set to 0.1 μm to 3.0 μm. In this embodiment, the adhesive part 90 may be the same adhesive as the adhesive of the second adhesive layer 70A.

In this embodiment, in the retardation plate 50 containing the cured layer of the polymerizable liquid crystal compound, the end surface 50E perpendicular to the bending axis is also covered by the adhesive portion 90, so the flexibility of the optical laminate 100 is improved.

(Third Embodiment) Next, the optical laminate 100 of the third embodiment of the present invention will be described with reference to FIG. 8.

The optical layered body 100 of this embodiment is different from the first embodiment in that an adhesive layer 70B is used instead of the second adhesive layer 70A. As the adhesive agent, the adhesive agent exemplified in the bonding layer 40 described above can be used. The thickness of the adhesive layer 70B can be set to 0.1 μm to 3.0 μm. The adhesive part 90 may be the same adhesive as the adhesive of the first adhesive layer 20A.

In this embodiment, in the retardation plate 50 containing the cured layer of the polymerizable liquid crystal compound, the end surface 50E perpendicular to the bending axis is also covered by the adhesive portion 90, so the flexibility of the optical laminate 100 is improved.

(Use of optical laminate) The optical layered body 100 may be arranged and installed in an image display device such as a liquid crystal display device or an organic EL display device such that the front panel becomes the visible side, that is, the outer side.

The optical layered body of this embodiment is excellent in flexibility, and it is hard to generate cracks especially even when held in a bent state. Therefore, it can be applied to a flexible display that can be bent, wound, or the like.

The display device is not particularly limited, and examples thereof include an organic electroluminescence (EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, an electroluminescence display device, and the like.

＜Manufacturing method of laminated body＞ The optical laminate shown in the first embodiment (FIG. 1) can be manufactured as follows, for example.

First, a sheet A having a structure of the front surface plate 10/first adhesive layer 20A, a circular polarizing plate 60, and a sheet B having a structure of the second adhesive layer 70A/back plate 80 are prepared.

Here, the planar shape of the sheet A, the circular polarizing plate 60, and the sheet B is set to a rectangle with long sides and short sides, and the width of the long side and/or the short side of the circular polarizing plate is made smaller than that of the sheet A and the sheet B. .

Next, sheet A/circular polarizing plate 60/sheet B are bonded in this order. At this time, bonding is performed so that the end surface of the circular polarizing plate enters more inside than the end surfaces of the sheet A and the sheet B, and pressure is applied to the laminate in the stacking direction after the bonding. Thereby, between the sheet A and the sheet B, the adhesive passes around the part where the circular polarizing plate 60 does not exist, and the adhesive portion 90 covering the end surface of the circular polarizing plate 60 (phase difference plate 50) is formed.

When producing the optical laminate shown in the second embodiment (FIG. 7 ), it is sufficient to proceed as follows.

First, the front surface plate 10, the circular polarizing plate 60, and the sheet B having the structure of the second adhesive layer 70A/back plate 80 are obtained. Here, the planar shape of the front surface plate 10, the circular polarizing plate 60, and the sheet B is set to a rectangle having long sides and short sides, and the width of the long side and/or the short side of the circular polarizing plate 60 is smaller than that of the front surface. Panel 10 and sheet B.

The adhesive is applied to the surface of the front surface plate 10 to form a non-adhesive portion of the circular polarizing plate 60 around the surface, and the circular polarizing plate 60 is adhered to the surface of the front surface plate 10. Then, the front surface plate 10 is attached to the sheet B so as to face each other, and pressure is applied.

The optical laminate shown in the third embodiment (FIG. 3) can also be manufactured in the same manner.

Examples and comparative examples are shown to explain the present invention more specifically, but the present invention is not limited by these examples. [Example]

(Preparation of each membrane) (Manufacturing of front panel) As the front surface plate, a hard-coated resin film with a thickness of 50 μm in which a hard-coated layer was formed on one side of the resin film was prepared. The resin film is a polyamideimide (PAI)-based resin film having a thickness of 40 μm, and the hard coat layer is a layer of a composition containing a dendrimer compound having a polyfunctional acrylic group at the end and having a thickness of 10 μm.

(Manufacture of circular polarizing plate A) After forming an alignment film on Triacetyl Cellulose (TAC) film (KC2UA, manufactured by Konica Minolta Co., Ltd., thickness 25 μm), it will contain dichroic pigments and polymerizable The composition of the liquid crystal compound is coated on the substrate, aligned and cured to obtain a polarizer layer with a thickness of 2.5 μm. On the polarizer layer, the composition for forming an overcoat layer (100 parts of water, polyvinyl alcohol resin powder (KL318, (stock) Kuraray (Kuraray, average polymerization degree 18000) 3 parts, polyamide epoxy resin (SR650 (30), manufactured by Sumika Chemtex (Stock)) as a crosslinking agent 1.5 parts) And the outer coating is formed. Thereby, a 29 μm-thick linear polarizing plate having a layer structure of TAC film/alignment film/polarizer layer/overcoat layer was obtained.

The λ/4 plate side of the phase difference plate was bonded to the outer coating layer of the obtained linear polarizing plate via an adhesive layer to obtain a circular polarizing plate A (thickness 43 μm). The thickness of the adhesive layer is 5 μm. The angle formed by the absorption axis of the linear polarizer and the slow axis of the retardation layer is 45°. The thickness of the retardation plate is 9 μm, and the layer structure is a λ/4 plate, an adhesive layer, and a positive C plate laminated in this order. The thickness of the adhesive layer is 5 μm. The λ/4 plate has a cured layer of a polymerizable liquid crystal compound and an alignment film, and the thickness is 3 μm. The positive C plate has a cured layer of a polymerizable liquid crystal compound and an alignment film, and has a thickness of 1 μm.

(Manufacturing of Circular Polarizing Plate B) A 2.0 μm urethane acrylic anti-diffusion layer 1 was formed on a 100 μm-thick PET film to obtain a laminate including an anti-diffusion layer 1/substrate (PET).

A 100 nm alignment film is formed on the anti-diffusion layer 1 of the laminate including the anti-diffusion layer 1/substrate (PET), and the alignment film is coated with a composition containing a polymerizable liquid crystal compound and a dichroic dye to harden it , Form a polarizer layer. The thickness of the obtained polarizer layer was 3 μm.

On the formed polarizer layer, a 1.0 μm anti-diffusion layer 2 containing polyvinyl alcohol and polyamide epoxy resin was formed. Thus, a linear polarizing plate including PET/anti-diffusion layer 1/AL1/polarizer layer/anti-diffusion layer 2 was obtained. A 5 μm acrylic adhesive layer 4 was laminated on the diffusion prevention layer 2 of the linear polarizing plate.

The linear polarizing plate and the λ/4 plate are laminated via the adhesive layer 4 laminated on the linear polarizing plate. Next, on the λ/4 plate, a positive C plate was laminated via another 5 μm acrylic adhesive layer 4. The λ/4 plate has a cured layer of a polymerizable liquid crystal compound and an alignment film, and the thickness is 2 μm. The positive C plate has a cured layer of a polymerizable liquid crystal compound and an alignment film, and has a thickness of 3 μm.

In this way, a circular polarizing plate B including PET/anti-diffusion layer 1/alignment film/polarizer layer/anti-diffusion layer 2/adhesive layer 4/λ/4 plate/adhesive layer 4/positive C plate was produced (except for PET The thickness outside is 21 μm).

(Manufacture of circular polarizing plate C: including linear polarizing plate of stretched PVA) A polyvinyl alcohol film with a thickness of 20 μm (the average degree of polymerization is about 2400, the degree of saponification is more than 99.9 mol%) is uniaxially stretched about 4 times by dry stretching, and the tension is maintained in pure water at 40°C. After being immersed for 40 seconds, it was immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.052/5.7/100 at 28°C for 30 seconds to perform dyeing treatment. Then, it was immersed in an aqueous solution with a weight ratio of potassium iodide/boric acid/water of 11.0/6.2/100 at 70°C for 120 seconds. Then, after washing with pure water at 8°C for 15 seconds, the film was dried at 60°C for 50 seconds while maintaining a tension of 300 N, and then dried at 75°C for 20 seconds to obtain a polyvinyl alcohol film aligned with iodine adsorption. A polarizer layer with a thickness of 7 μm on top.

A water-based adhesive was coated on one surface of the polarizer layer, and the protective layer A was bonded. At this time, bonding was performed so that the stretching direction of the protective layer A was 45 degrees with respect to the absorption axis of the polarizer layer. As the protective layer A, a film (trade name "COP25ST-HC" manufactured by Nippon Paper Co., Ltd.) formed on a stretched film containing a norbornene-based resin having a thickness of 25 μm and a hard coat layer having a thickness of 3 μm was used. A water-based adhesive was applied to the other surface of the polarizer layer, and the protective layer B was bonded. Then, drying was performed to obtain a linear polarizing plate (thickness 57 μm). As the protective film B, a triacetyl cellulose film with a thickness of 20 μm [trade name "ZRG20SL" manufactured by Fuji Film Co., Ltd.] was used.

The water-based adhesive is made by dissolving 3 parts of carboxyl-modified polyvinyl alcohol (trade name "KL-318" obtained from Kuraray Co., Ltd.) in 100 parts of water, and adding 1.5 parts as a water-soluble ring A polyamide epoxy-based additive for an oxygen resin [trade name "SUMIREZ RESIN 650 (30)" manufactured by Taoka Chemical Industry Co., Ltd., an aqueous solution with a solid content of 30%)].

By the same method as [Production of Retardation Film 2] in Japanese Patent Laid-Open No. 2019-185007, a laminate including a substrate, an alignment film, and a cured layer of a polymerizable liquid crystal compound was produced. Adhesive A (a sheet-shaped adhesive with a thickness of 5 μm (manufactured by Lintec Co., Ltd.) is laminated on the cured layer of the polymerizable liquid crystal compound in the laminate. Next, the substrate is peeled from the laminate, and the Laminated adhesive B (a sheet-like adhesive with a thickness of 25 μm (manufactured by Lintec) Co., Ltd.) exposed after peeling. In this way, a plate containing adhesive A and λ/4 (with a polymerizable liquid crystal compound) The hardened material layer and alignment film of 3 μm thick), and the retardation plate with adhesive B on both sides (thickness 33 μm).

On the protective layer B of the linear polarizing plate, the double-sided adhesive phase difference plate is bonded via the adhesive A in the double-sided adhesive phase difference plate. The slow axis of the cured layer of the polymerizable liquid crystal compound is 45 degrees with respect to the absorption axis of the polarizer layer, and is 90 degrees with respect to the stretching direction of the protective layer A. In this way, a circular polarizing plate C (thickness 90 μm) including protective layer A, water-based adhesive layer, polarizer layer, water-based adhesive layer, protective layer B, adhesive A, λ/4 plate, and adhesive B was produced. .

The circular polarizing plate is cut into a rectangular shape so that the slow axis of the λ/4 plate is parallel to the long side. At this time, the stretching direction of the protective film A is parallel to the short side direction.

(Production of touch sensor panel) The touch sensor panel having the structure shown in FIG. 5 and FIG. 6 was prepared. The separation layer 122 was an acrylic resin layer with a thickness of 0.5 μm, the protective layer 123 was an acrylic resin layer with a thickness of 3 μm, and the first conductive layer 127 was an indium tin oxide (ITO) layer with a thickness of 0.1 μm. The connection wiring 125 is an APC (Ag Palladium Copper) layer with a thickness of 0.2 μm.

The second insulating layer 129 is a cured product of the photosensitive resin composition described in Example 3 of JP 2016-14877 A, and has a thickness of 2 μm.

The through-hole portion b and the connecting portion 128c (second conductive layer) are set as an indium tin oxide (ITO) layer, and the thickness of the connecting portion 128c on the second insulating layer is set to 0.12 μm.

The first insulating layer is a cured product of the photosensitive resin composition described in Example 3 of JP 2016-14877 A, and is formed to have a thickness of 2 μm.

The base layer 131 is made of a cyclic olefin (Cycloolefin Polymer (COP)) film (thickness 23 μm) (ZF-14, manufactured by ZEON), and the bonding layer 135 is set to A cured layer of an ultraviolet-curable adhesive composition.

(Manufacture of the first adhesive sheet) 25 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were put into a 500 ml 4-neck reactor equipped with a cooling device so that the temperature can be easily adjusted by refluxing nitrogen gas. After 50 parts by weight of 2-Ethylhexyl acrylate (2-EHA), 15 parts by weight of methyl acrylate (MA), and 10 parts by weight of isobornyl acrylate (IBOA), 100 parts by mass of ethyl acetate (EAc) as a solvent was added. Thereafter, nitrogen gas was purged for 1 hour in order to remove oxygen, and the temperature was maintained at 60°C. After making the mixture uniform, 0.07 parts by mass of azobisisobutyronitrile (AIBN) as a reaction initiator was added to 100 parts by mass of the mixture. It was allowed to react for about 5 hours to produce an acrylic copolymer A1 having a weight average molecular weight of about 800,000.

On the release film coated with a silicone release agent, 0.5 parts by mass of crosslinking agent (CORONATE-L, Tosoh Co., Ltd.). The coated mixture was dried at 100°C for 1 minute. The thickness of the dried adhesive is 50 μm. By joining the release film thereon, a first adhesive sheet having a release film/first adhesive layer/release film was produced.

(Manufacturing of the second adhesive sheet) Into a 500 ml 4-neck (4-neck) reactor equipped with a cooling device such that nitrogen is refluxed to easily adjust the temperature, 20 parts by mass of methyl acrylate (MA), After 40 parts by mass of 4-hydroxybutyl acrylate (4-HBA) and 40 parts by mass of octyl acrylate (OA), nitrogen was purged for 1 hour to remove oxygen, and the temperature was maintained at 80°C. After the mixture was uniformly mixed, 3 parts by mass of hydroxycyclohexyl phenyl ketone as a reactive photoinitiator was added to the mixture. Thereafter, while stirring, ultraviolet rays (10 mW) were irradiated to produce acrylic copolymer B1. On the release film coated with silicone release agent, 10 parts by mass of reactive diluent (isodecyl acrylate) and 0.1 parts by mass of photopolymerization are added to 100 parts by mass of acrylic copolymer B1. A mixture of initiators (hydroxycyclohexyl phenyl ketone). A high-pressure mercury UV lamp was used to irradiate with a light quantity of 500 mJ/cm ² to obtain an adhesive with a thickness of 50 μm. Then, by bonding the release film to the adhesive, a second adhesive sheet having a release film/second adhesive layer/release film is obtained.

(Example 1) The surface of the resin film in the front surface plate was corona treated, and the release film on one side of the first adhesive sheet was peeled off and joined to the exposed surface, thereby fabricating the front surface plate with the first adhesive layer. Cut it to a width of 120 mm × a length of 180 mm. Then, the release film of the front surface plate with the first adhesive layer was removed and joined to the TAC film side of the circular polarizing plate A cut into a width of 110 mm×170 mm. At this time, in the width direction of the circularly polarizing plate A, the positions of both ends are aligned with the end of the front surface plate with the first adhesive layer, and the ends are respectively 5 mm inside to join, and the front surface is made A laminate of panel/first adhesive layer/circular polarizing plate A.

On the other hand, in the touch panel, corona treatment is performed on the surface of the substrate side, and the release film on the side of the second adhesive sheet is peeled off and bonded to the exposed surface to produce a back panel with a second adhesive layer. Cut it into a size of 120 mm wide by 180 mm long. Then, the back plate with the second adhesive layer and the front surface plate/first adhesive layer/circular polarizing plate were joined so that the outermost ends thereof were aligned with each other, thereby fabricating the optical laminate of Example 1.

(Example 2) Change circular polarizer A into circular polarizer B, and cut circular polarizer B into a size of 114 mm × 174 mm in width, peel off the PET on the anti-diffusion layer 1 of circular polarizer B, and connect the anti-diffusion layer 1 with the tape The position of the front surface plate of the first adhesive layer in the width direction of the circular polarizing plate B is such that the end of the front surface plate with the first adhesive layer enters the position 3 mm inside each Except for bonding the first adhesive layer, the optical layered body of Example 2 was produced in the same manner as in Example 1 described above.

(Example 3) Cut the size of the circular polarizer A to a width of 119 mm×179 mm. In the width direction of the circular polarizer A, the positions of both ends are aligned with the ends of the front surface plate with the first adhesive layer. The bonding was performed at a position of 0.5 mm inside, and the same as in Example 1 except for this.

(Example 4) It is the same as in Example 2 except that the circular polarizing plate A is replaced with the circular polarizing plate C.

(Comparative example 1) The size of the circular polarizer A is cut to a width of 120 mm×180 mm, and the positions of both ends in the width direction of the circular polarizer A overlap with the end of the front surface plate with the first adhesive layer. Except for this, it is the same as in Example 1.

[Static bending durability test] The method of static bending durability test (mandrel bending test) is shown. First, the optical laminate 100 is cut into a test piece of 1 cm×10 cm. The test plate 503 was placed with the front surface plate 10 side of the optical laminate 100 facing upward, and an iron rod 502 with a diameter of 5 mm was placed thereon (FIG. 9(A) ). The layered body was bent by hands so that the front surface panel was inside, and the laminate was fixed (FIG. 9(B) ). Based on the period during which cracks did not occur in the phase difference plate, the static bending durability was evaluated as follows.

Static bending durability A: No cracks occurred after 30 days. B: Cracks occurred after 30 days. C: Cracks occurred at the time point after 10 days.

[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Comparative example 1 Plane shape of the front surface plate with the first adhesive layer [mm] 120×180 Plane shape of circular polarizer [mm] 110×170 114×174 119×179 114×174 120×180 Types of circular polarizers A B A C A Plane shape of back panel with second adhesive layer [mm] 120×180 The thickness of the adhesive on the end face of the circular polarizer D [mm] 5 3 0.5 3 0 Static bending durability A A B B C

10: Front panel 10E: end face 10W: The width between the two ends of the front surface plate 10 12: Hard coating 14: Base film 20: The first bonding layer 20A: The first adhesive layer (the first bonding layer) 20AE: end face 20B: Adhesive layer 30: Linear polarizer 32, 36: protective layer 34: Polarizer layer 40: Laminated layer 50: Phase difference plate 50E: end face 52: λ/4 plate 54: Laminated layer 56: Positive C board 58: λ/2 plate 60: Circular polarizing plate 60E: end face 60W: The width between the two ends 60E of the circular polarizer 60 70: The second bonding layer 70A: The second adhesive layer (the second bonding layer) 70AE: end face 70B: Adhesive layer 80: back panel 80E: end face 80W: The width between the two ends of the back panel 80 90: Adhesive Department 90E: end face 100: Optical laminate 111: first insulating layer 120: Touch sensor layer 121: support layer 122: Separation layer 123: protective layer 124: refractive index adjustment layer 125: Connection wiring 127: first conductive layer 127a, 127b: unit pattern 127c: connecting part 128: second conductive layer 128c: connecting part 129: second insulating layer 130: basic layer 131: Substrate layer 135: Laminated layer 502: Iron Rod 503: Test Board b: Through hole D: thickness

FIG. 1 is a schematic cross-sectional view of the optical laminate of the first embodiment. Fig. 2 is a schematic cross-sectional view of an example of a front surface plate in the optical laminate. Fig. 3 is a schematic cross-sectional view of an example of a linear polarizing plate in the optical laminate. Fig. 4 is a schematic cross-sectional view of an example of a phase difference plate in the optical laminate. FIG. 5 is a schematic cross-sectional view showing an example of the back plate (touch panel sensor) in the optical laminate. 6 is a plan view of the unit pattern 127a to the unit pattern 127b constituting the first conductive layer 127 in FIG. 5 and the connecting portion 128c constituting the second conductive layer 128. Fig. 7 is a schematic cross-sectional view of the optical laminate of the second embodiment. FIG. 8 is a schematic cross-sectional view of the optical laminate of the third embodiment. Fig. 9 is a schematic cross-sectional view showing the state of the static bending durability test of the embodiment of the present invention.

10: Front panel

10E: end face

10W: The width between the two ends of the front surface plate 10

20: The first bonding layer

20A: The first adhesive layer

20AE: end face

30: Linear polarizer

40: Laminated layer

50: Phase difference plate

50E: end face

60: Circular polarizing plate

60E: End face of circular polarizer 60

60W: The width between the two ends 60E of the circular polarizer 60

70: The second bonding layer

70A: second adhesive layer

70AE: end face

80: back panel

80E: end face

80W: The width between the two ends of the back panel 80

90: Adhesive Department

90E: end face

100: Optical laminate

D: thickness

Claims (9)

An optical laminate, which in turn includes a front surface plate, a first bonding layer, a circular polarizing plate, a second bonding layer, and a back plate, wherein: The circularly polarizing plate has a retardation plate including a cured layer of a polymerizable liquid crystal compound, At least one of the first bonding layer and the second bonding layer is an adhesive layer, The optical layered body further includes an adhesive part that covers one or both end faces of the retardation plate in a cross section of the optical layered body along the lamination direction. The optical layered body according to claim 1, wherein in the cross section, when the thickness of the adhesive portion in a direction perpendicular to the layering direction is set to D, 0.5 mm≦D≦5 mm is satisfied. The optical laminate according to claim 1, wherein the thickness of the cured layer of the polymerizable liquid crystal compound is 5 μm or less. The optical laminate according to any one of claims 1 to 3, wherein the phase difference plate has a positive C plate, and the positive C plate has a cured layer of the polymerizable liquid crystal compound. The optical laminate according to any one of claims 1 to 4, wherein in the cross section, the adhesive portion covers the entire one or both end surfaces of the circular polarizing plate. The optical laminate according to any one of claims 1 to 5, wherein in the cross section, one end surface of the front surface plate, one end surface of the adhesive layer, and the back plate One end surface respectively protrudes in a direction orthogonal to the stacking direction more than one end surface of the circular polarizing plate. The optical laminate according to any one of claims 1 to 5, wherein in the cross section, two end surfaces of the front surface plate, two end surfaces of the adhesive layer, and the back The two end surfaces of the panel respectively protrude in a direction orthogonal to the stacking direction than the two end surfaces of the circular polarizing plate. The optical laminate according to any one of claims 1 to 3, wherein both the first bonding layer and the second bonding layer are adhesive layers. The optical laminate according to any one of claims 1 to 7, which is used in a flexible display.

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