TW202118342A - Display device and base material laminate includes an optical film member, a first adhesive layer, a window member, a second adhesive layer, and a laminated structure - Google Patents

Abstract

The object of the invention is configured to have a bendable display device that can realize a display device which can prevent layers or members with weak flexural resistance from breaking when the display device is bent. As a solution, the display device is bendable and includes: an optical film member, a first adhesive layer, a window member, a second adhesive layer, and a laminated structure, wherein the window member is laminated on one side of the optical film member through the first adhesive layer, and the laminated structure is laminated on the other side of the optical film member through the second adhesive layer and includes a panel member. The display device is characterized in that: the window member has a hard coating layer on the surface at the side opposite to the first adhesive layer, and the laminated structure has a layer that is more easily broken than the window member and the optical film member while being bent and deformed on the surface at the side where the second adhesive layer is located. The following equations (1) and (2) will be established according to the following strain differences A, A', B, and B', thereby the elongation rate of the aforementioned easy-to-break layer and the hard coating layer after bending deformation is suppressed to a value smaller than their individual elongation at break. When the display device is bent such that the window member faces outward at an angle of 180 DEG and when the distance between the parallel opposite outermost surfaces of the display device becomes 4mm after the bending deformation in a state of the angle of 180 DEG, the difference between the strain generated on the surface of the optical film member in the direction perpendicular to the bending radius direction and the strain generated on the surface of the window member facing the first adhesive layer in the direction perpendicular to the direction of the bending radius is defined as A. When the optical film member and the window member are bent at an angle of 180 DEG individually in a single layer status to make the bent-deformed outer side and inner side have the same way as the bent-deformed display device and when the distance between the parallel opposite outermost surfaces of the respective optical film member and the window member becomes 4mm after the bending deformation is in a state of the angle of 180 DEG, the difference between the strain generated on the outer surface of the optical film member in the direction perpendicular to the direction of the bending radius and the strain generated on the inner surface of the window member in the direction perpendicular to the direction of the bending radius is defined as A'. 0.8 < A/A' < 1.2 (1); 0 < B/B' < 0.9 (2)

Description

Display device and substrate laminate

The present invention relates to a display device configured to be bendable and a substrate laminate used for the display device.

For example, as shown in Patent Document 1, a touch sensor-integrated organic EL display device is known. Regarding the organic EL display device of Patent Document 1, as shown in FIG. 1, an optical laminate 920 is provided on the viewing side of the organic EL display panel 901, and a touch panel 930 is provided on the viewing side of the optical laminate 920. The optical layered body 920 includes a polarizer 921 and a retardation film 923 with protective films 922-1 and 922-2 bonded on both sides, and the polarizer 921 is provided on the viewing side of the retardation film 923. In addition, the touch panel 930 has a structure in which transparent conductive films 916-1 and 916-2 are arranged via a spacer 917, and the transparent conductive films 916-1 and 916-2 have substrate films 915-1 and 915- layered with each other. 2 and the structure of transparent conductive layers 912-1, 912-2.

On the other hand, in recent years, it is expected to realize a flexible organic EL display device, which is an organic EL display device with better portability. Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2014-157745

The problem to be solved by the invention However, the conventional organic EL display device shown in Patent Document 1, for example, is not designed in consideration of the bending function. As long as the plastic film is used as the base material of the organic EL display panel, flexibility can be imparted to the organic EL display panel. However, the transparent conductive layer included in the touch sensor component of the conventional organic EL display device, the thin-film sealing layer of the organic EL display panel, and the hard coat layer provided on the surface of the window component, etc. The organic EL display device breaks when it is bent.

Therefore, the object of the present invention is to realize a display device that can prevent the layer or member with fragile flexibility from breaking when facing the display device when it is bent to face the display device.

Means to solve the problem One aspect of the present invention provides a display device which is bendable and has: an optical film member, a first adhesive layer, a window member, a second adhesive layer, and a laminated structure, wherein the window member is through the first adhesive Laminated on one side of the optical film member, and the laminated structure system is laminated on the other side of the optical film member through the second adhesive layer and includes a panel member; The display device is characterized by: The window member has a hard coating on the surface opposite to the first adhesive layer; The layered structure has a layer on the surface of the second adhesive layer side that is easier to break when bending and deforming than the window member and the optical film member; The following equations (1) and (2) are established between the following strain differences A, A', B, and B', thereby the elongation of the aforementioned easy-to-break layer and the aforementioned hard coating after bending deformation It is suppressed to a value smaller than the respective elongation at break: The display device is bent at an angle of 180° to the outside in the form of the window member, and the bend is deformed into a state of being bent at an angle of 180°. The distance between the parallel and opposite outermost surfaces of the display device becomes At 4mm, the strain in the direction orthogonal to the bending radius generated on the one surface of the optical film member, and the strain in the direction orthogonal to the bending radius generated on the surface of the window member facing the first adhesive layer The difference is set to A; In the same manner as after bending and deforming the outer side and the inner side of the display device, the optical film member and the window member are bent at an angle of 180° in the state of a single layer, and the bending is changed. When the distance between the opposing outermost surfaces of the optical film member and the window member in a state of being bent at an angle of 180° is 4mm, the direction of the bending radius generated on the outer surface of the optical film member The difference between the strain in the perpendicular direction and the strain in the direction perpendicular to the direction of the bending radius generated on the inner surface of the aforementioned window member is set to A'; The display device is bent at an angle of 180° to the outside in the form of the window member, and the bend is deformed into a state of being bent at an angle of 180°. The distance between the parallel and opposite outermost surfaces of the display device becomes At 4mm, the strain in the direction perpendicular to the bending radius generated on the other surface of the optical film member, and the strain in the direction perpendicular to the bending radius generated on the surface of the laminated structure facing the second adhesive layer Set the strain difference as B; In the same manner as after bending and deforming the outer side and the inner side of the display device, the optical film member and the laminated structure are bent at an angle of 180° in the state of a single layer, and the bending is performed. When the distance between the parallel and opposite outermost surfaces of the optical film member and the laminated structure in the state of being bent at an angle of 180° becomes 4mm, the bending and bending of the inner surface of the optical film member The difference between the strain in the direction perpendicular to the radial direction and the strain in the direction perpendicular to the bending radius generated on the outer surface of the aforementioned laminated structure is set to B'; 0.8＜A/A’＜1.2　　　　・・・・(1) 0＜B/B’＜0.9　　　　・・・・(2).

The aforementioned optical film member can be a circularly polarized functional film laminate in which a retardation film is laminated on a polarizing film.

The aforementioned polarizing film can be a laminate in which a polarizer and a polarizer protective film located on at least one side of the polarizer are laminated.

The aforementioned polarizer protective film may be made of acrylic resin.

The layer that can make the aforementioned window member and the optical film member easier to break is a film sealing layer formed on the surface of the panel member on the side of the second adhesive layer.

The laminated structure may be the following: a film sealing layer is formed on the surface of the panel member on the side of the second adhesive layer, and a third adhesive layer is formed on the surface of the film sealing layer on the opposite side of the panel member A touch sensor member is laminated, and a transparent conductive layer is formed on the surface of the touch sensor member opposite to the panel member, and the transparent conductive layer is compared with the window member and the optical film The form of a layer that is more susceptible to breaking is laminated on the second adhesive layer.

The shear elastic modulus of the second adhesive layer can be made greater than the shear elastic modulus of the first adhesive layer. It is possible to further have a fourth adhesive layer on the surface of the panel member opposite to the second adhesive layer, and a protective member can be layered through the fourth adhesive layer.

The shear elastic modulus of the fourth adhesive layer can be made smaller than the shear elastic modulus of the second adhesive layer and smaller than the shear elastic modulus of the third adhesive layer.

One aspect of the present invention provides a substrate laminate that is used in the display device and has: the optical film member; the window member is laminated on one surface of the optical film member through the first adhesive layer; and The control sensor member is laminated on the other side of the optical film member through the second adhesive layer and includes the transparent conductive layer.

Invention effect According to the present invention, for a display device configured to be bendable, it is possible to realize a display device that can prevent a layer or a member with fragile flexibility from breaking when facing the display device when it is bent.

Hereinafter, embodiments of the display device of the present invention will be described in detail with reference to the drawings.

[Optical Film Components] The optical film member used in the display device of the present invention can use polarizers, polarizing films, protective films made of transparent resin materials or films such as retardation films, etc., and some or all combinations of these, especially for polarizing A film laminate with a circularly polarizing function in which a retardation film is laminated on the film. In addition, the aforementioned optical film member does not include adhesion layers such as the first adhesion layer described later.

The thickness of the aforementioned optical film member is preferably 92 μm or less, preferably 60 μm or less, and more preferably 10-50 μm. If it is in the aforementioned range, it will not hinder the deflection and is a preferred aspect. ＜Polarizers＞ The polarizer contained in the optical film member of the present invention may use a polyvinyl alcohol (PVA)-based resin that has been oriented with iodine, which is stretched by an stretching step such as aerial stretching (dry stretching) or a boric acid water stretching step.

The manufacturing method of the polarizer is representatively the manufacturing method (single-layer stretching method) described in Japanese Patent Laid-Open No. 2004-341515, which includes a step of dyeing a single-layer body of a PVA-based resin and a step of stretching. Also, for example, Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, Japanese Patent Laid-Open No. 2001-343521, International Publication No. 2010/100917, and Japanese Patent Laid-Open No. 2012- The manufacturing method described in 073563 and Japanese Patent Laid-Open No. 2011-2816 includes a step of extending a PVA-based resin layer and a resin substrate for stretching in a laminate state and a step of dyeing. As long as this method is used, even if the PVA-based resin layer is thin, it is supported by the resin base material for stretching, so it can be stretched without breaking or other problems due to stretching.

The thickness of the aforementioned polarizer is 20 μm or less, preferably 12 μm or less, preferably 9 μm or less, more preferably 1 to 8 μm, and particularly preferably 3 to 6 μm. If it is in the aforementioned range, it will not hinder the deflection and is a preferred aspect.

＜Polarizing film＞ As long as the characteristics of the present invention are not impaired, the aforementioned polarizer may also be laminated with a polarizer protective film (not shown in the drawings) on at least one side through the adhesive (layer). Adhesives can be used for the bonding treatment of the polarizer and the polarizer protective film. Examples of the adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. The aforementioned adhesive is generally used as an adhesive composed of an aqueous solution, and generally contains 0.5 to 60% by weight of solid content. In addition to the above, the adhesive for the polarizer and the polarizer protective film can also include ultraviolet curing type adhesives, electron beam curing type adhesives, and the like. The adhesive for electron beam curable polarizing films exhibits good adhesion to the above-mentioned various polarizer protective films. In addition, the adhesive used in the present invention may contain a metal compound filler. In addition, in the present invention, a polarizer and a polarizer protective film bonded to each other through an adhesive (layer) may be referred to as a polarizing film.

＜Retardation film＞ The optical film member used in the present invention may include a retardation film, and the retardation film may be obtained by stretching a polymer film or by aligning and immobilizing a liquid crystal material. In this specification, a retardation film refers to a film having birefringence in the plane and/or thickness direction.

Examples of retardation films include anti-reflection retardation films (refer to Japanese Patent Laid-Open No. 2012-133303 [0221], [0222], [0228]), and retardation films for viewing angle compensation (refer to Japanese Patent Laid-Open 2012- No. 133303 [0225], [0226]), a tilt-aligned retardation film for viewing angle compensation (refer to Japanese Patent Laid-Open No. 2012-133303 [0227]), etc.

As long as the retardation film has the above-mentioned functions substantially, for example, retardation value, arrangement angle, three-dimensional birefringence, single layer or multilayer, etc. are not particularly limited, and known retardation films can be used.

The thickness of the aforementioned retardation film is preferably 20 μm or less, preferably 10 μm or less, more preferably 1 to 9 μm, and particularly preferably 3 to 8 μm. If it is in the aforementioned range, it will not hinder the deflection and is a preferred aspect.

In this specification, Re[550] refers to the in-plane retardation value measured at 23°C with a wavelength of 550nm. Re[550] can be used when the refractive index in the slow axis direction and the fast axis direction of the retardation film at a wavelength of 550nm are nx and ny, and d(nm) is the thickness of the retardation film, by the formula: Re[ 550]=(nx-ny)×d. In addition, the slow axis refers to the direction in which the in-plane refractive index becomes the largest.

The in-plane birefringence Δn of nx-ny of the present invention is 0.002 to 0.2, preferably 0.0025 to 0.15.

The above-mentioned retardation film preferably has an in-plane retardation value (Re[550]) measured with light having a wavelength of 550 nm at 23° C. greater than that measured with light having a wavelength of 450 nm (Re[450]). The retardation film with such wavelength dispersion characteristics can exhibit long-wavelength retardation as long as the aforementioned ratio is within this range, and can obtain ideal retardation characteristics at each wavelength in the visible region. For example, when used in an organic EL display, the wavelength-dependent retardation film can be made as a quarter-wave plate and bonded with a polarizing plate to make a circular polarizing plate, etc., so that the wavelength dependence of the hue can be realized. Few neutral polarizers and display devices. On the other hand, when the aforementioned ratio is out of this range, the wavelength dependence of the reflected hue becomes greater, and a coloring problem occurs in the polarizer or the display device.

The ratio of Re[550] to Re[450] (Re[450]/Re[550]) of the above retardation film is 0.8 or more and less than 1.0, and preferably 0.8 to 0.95.

The above-mentioned retardation film preferably has an in-plane retardation value (Re[550]) measured with light with a wavelength of 550 nm at 23°C being smaller than an in-plane retardation value (Re[650]) measured with light with a wavelength of 650 nm. The retardation film with such wavelength dispersion characteristics has a fixed retardation value in the red region. For example, when used in a liquid crystal display device, it can improve the phenomenon of light leakage due to the viewing angle or the phenomenon that the displayed image is red (also known as Redness phenomenon).

The ratio of Re[650] to Re[550] (Re[550]/Re[650]) of the above retardation film is 0.8 or more and less than 1.0, and preferably 0.8 to 097. By setting Re[550]/Re[650] in the above range, for example, when the above-mentioned retardation film is used in an organic EL display, more excellent display characteristics can be obtained.

Re[450], Re[550], Re[650] can be measured using the product name "AxoScan" manufactured by Axometrics.

In one embodiment, the retardation film of the present invention is produced by stretching a polymer film to make it oriented.

The above-mentioned method of stretching the polymer film can adopt any suitable stretching method according to the purpose. The above-mentioned stretching method suitable for the present invention includes, for example, a lateral uniaxial stretching method, a longitudinal and horizontal simultaneous biaxial stretching method, and a vertical and horizontal stepwise biaxial stretching method. The stretching mechanism can use any suitable stretching machine such as a tenter stretching machine and a biaxial stretching machine. Preferably, the stretching machine includes a temperature control mechanism. When heating and stretching, the internal temperature of the stretching machine can be continuously changed, and it can also be continuously changed. The step can be one time or it can be divided into two or more times. The extension direction is preferably along the film width direction (TD direction) or oblique direction.

In other embodiments, the retardation film of the present invention may use a retardation layer produced by aligning and fixing a liquid crystal material. Each retardation layer may be an oriented solidified layer of a liquid crystal compound. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be much larger than that of the non-liquid crystal material. Therefore, the thickness of the retardation layer required to obtain the desired in-plane retardation can be greatly reduced. many. As a result, the circular polarizer (and ultimately the organic EL display device) can be made thinner. In this specification, the "directional curing layer" refers to a layer in which the liquid crystal compound is oriented in a predetermined direction in the layer, and its orientation state has been fixed. In this embodiment, it means that the rod-shaped liquid crystal compound is aligned in the direction of the slow axis of the retardation layer (orientation along the plane). The liquid crystal compound may be, for example, a liquid crystal compound (nematic liquid crystal) whose liquid crystal phase is a nematic phase. For this liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal properties of the liquid crystal compound can be expressed by lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. This is because the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking the liquid crystal monomer. After aligning the liquid crystal monomers, for example, by polymerizing or crosslinking the liquid crystal monomers with each other, the above-mentioned alignment state can be fixed by this. Here, a polymer is formed by polymerization, and a three-dimensional network structure is formed by cross-linking, but these are non-liquid crystalline. Therefore, the formed retardation layer will not be transformed into a liquid crystal phase, a glass phase, or a crystal phase due to temperature changes, which are characteristic of liquid crystal compounds, for example. As a result, the layer becomes a retardation layer that is not affected by temperature changes and is extremely stable.

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity will vary depending on its type. Specifically, the temperature range is preferably 40°C to 120°C, more preferably 50°C to 100°C, and most preferably 60°C to 90°C.

Any appropriate liquid crystal monomer can be used as the above-mentioned liquid crystal monomer. For example, the polymerizable mesogen compounds described in Japanese Patent Special Publication 2002-533742 (WO00/37585), EP358208 (US5211877), EP66137 (US4388453), WO93/22397, EP0261712, DE19504224, DE4408171, GB2280445, etc. can be used. Specific examples of the polymerizable mesogen compound may include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Sillicon-CC3767. The liquid crystal monomer is preferably, for example, a nematic liquid crystal monomer.

The orientation curing layer of the liquid crystal compound can be formed by performing orientation treatment on the surface of a predetermined substrate, and coating the surface with a liquid crystal compound-containing coating solution to align the liquid crystal compound in the direction corresponding to the orientation treatment. , And fix the orientation state. In one embodiment, the substrate is any suitable resin film, and the directional curing layer formed on the substrate can be transferred to the surface of the polarizer. At this time, the angle formed by the absorption axis of the polarizer and the slow axis of the liquid crystal orientation curing layer is 15°. In addition, the phase difference of the liquid crystal orientation cured layer is λ/2 (approximately 270 nm) with respect to the wavelength of 550 nm. In addition, a liquid crystal orientation curing layer with a wavelength of λ/4 (approximately 140 nm) relative to the wavelength of 550 nm is formed on the substrate that can be transferred in the same way as above, and the absorption axis of the polarizer is slower than the 1/4 wavelength plate. Laminated on the 1/2 wavelength plate side of the laminated body of the polarizer and the 1/2 wavelength plate so that the angle formed by the axis becomes 75°.

＜Polarizer protective film＞ The polarizer protective film formed of a transparent resin material used in the display device of the present invention can use cycloolefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, polyester resins, and (meth)acrylic resins. Wait.

The thickness of the aforementioned polarizer protective film is preferably 5-60 μm, more preferably 10-40 μm, more preferably 10-30 μm, and surface treatment layers such as anti-glare layer and anti-reflection layer can be appropriately provided. If it is in the aforementioned range, it will not hinder the deflection and is a preferred aspect. The optical laminate film according to the present invention the moisture-permeable protective polarizer of 200g / m ² or less, is suitably 170g / m ² or less, more appropriate to 130g / m ² or less, ² or less is particularly appropriate 90g / m.

[Window widget] In order to prevent damage to the optical film member, the touch sensor member, and the panel member, the window member is arranged on the outermost surface of the viewing side of the display device.

The window member generally has a window film or window glass. The window film or window glass is provided with a hard coating. That is, the aforementioned window member has a hard coat layer on the surface opposite to the first adhesive layer described later in the display device. The window glass can be, for example, a thin glass substrate. High flexibility, high transparency, and high hardness are required for optical laminates applied to bendable display devices. The material of the window film is not particularly limited as long as it satisfies these physical properties.

＜Window film＞ The window film can be, for example, a transparent resin film. The resin constituting the transparent resin film may, for example, be selected from polyimide resins, polyamide resins, polyester resins, cellulose resins, acetate resins, styrene resins, turquoise resins, and cyclic resins. At least one of an oxygen-based resin, a polyolefin-based resin, a polyetheretherketone-based resin, a sulfide-based resin, a vinyl alcohol-based resin, a urethane-based resin, an acrylic resin, and a polycarbonate-based resin. However, the resin constituting the transparent resin film is not limited to these.

＜Hard coating＞ The hard coat layer is formed by applying a curable coating agent to the surface of a layer (for example, a window film) that becomes a base and hardening it.

As the coating agent, for example, those used for optical films can be used. The coating agent may include, for example, acrylic coating agent, melamine coating agent, urethane coating agent, epoxy coating agent, silicone coating agent, inorganic coating agent, but not Limited to these.

The coating agent may also contain additives. Additives include, for example, silane coupling agents, colorants, dyes, powders or particles (pigments, inorganic or organic fillers, particles of inorganic or organic materials, etc.), surfactants, plasticizers, antistatic agents, and surface lubricants Agents, leveling agents, antioxidants, light stabilizers, ultraviolet absorbers, polymerization inhibitors, antifouling materials, etc., but not limited to these.

[First Adhesive Layer] The first adhesive layer used in the display device of the present invention is an area layer window member that can penetrate through it to be an area layer of the optical film member. The adhesive composition constituting the first adhesive layer used in the display device of the present invention may include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, and polysiloxane adhesives. Amide-based adhesives, urethane-based adhesives, fluorine-based adhesives, epoxy-based adhesives, polyether-based adhesives, etc. In addition, the adhesive constituting the first adhesive layer may be used alone or in combination of two or more types. However, from the viewpoints of transparency, processability, durability, adhesion, flex resistance, etc., it is preferable to use an acrylic adhesive alone.

＜(Meth)acrylic polymer＞ When an acrylic adhesive is used as the adhesive composition constituting the first adhesive layer, it is preferable to contain a (meth)acrylic monomer having a linear or branched C1-C24 alkyl group as the monomer unit的(meth)acrylic polymer. By using the aforementioned (meth)acrylic monomer having a linear or branched C1-C24 alkyl group, an adhesive layer with excellent flexibility can be obtained. In addition, the (meth)acrylic polymer in the present invention refers to acrylic polymer and/or methacrylic polymer, and (meth)acrylate refers to acrylate and/or methacrylate.

Specific examples of (meth)acrylic monomers having a linear or branched C1-C24 alkyl group constituting the main skeleton of the aforementioned (meth)acrylic polymer include methyl (meth)acrylate Ester, ethyl (meth)acrylate, n-butyl (meth)acrylate, secondary butyl (meth)acrylate, tertiary butyl (meth)acrylate, isobutyl (meth)acrylate, (meth)acrylate Base) n-pentyl acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethyl (meth)acrylate Hexyl ester, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, (meth)acrylate Yl)isodecyl acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, etc., among which the glass transition temperature (Tg) is generally low The monomer is still a viscoelastic body in the faster speed region when flexed. Therefore, from the point of view of flexibility, the (methyl group) having a linear or branched alkyl group with 4 to 8 carbon atoms ) Acrylic monomers are preferred. The aforementioned (meth)acrylic monomers can be used singly or in two or more types.

The aforementioned (meth)acrylic mono-system having a linear or branched C1-C24 alkyl group constitutes the main component of the total monomer of the (meth)acrylic polymer. Here, the “main component” means that among the total monomers constituting the (meth)acrylic polymer, a (meth)acrylic monomer having a linear or branched C1-C24 alkyl group is preferably 80 to 100% by weight, preferably 90 to 100% by weight, more preferably 92 to 99.9% by weight, and particularly preferably 94 to 99.9.

When an acrylic adhesive is used as the adhesive composition constituting the first adhesive layer, it is preferable to contain a (meth)acrylic polymer containing a hydroxyl-containing monomer having a reactive functional group as a monomer unit. By using the aforementioned hydroxyl-containing monomer, an adhesive layer with excellent adhesion and flexibility can be obtained. The aforementioned hydroxyl-containing single system is a compound containing a hydroxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group.

The aforementioned hydroxyl-containing monomers specifically include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyethyl (meth)acrylate. Hexyl ester, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate and other hydroxyalkyl (meth)acrylates or (4- Hydroxymethylcyclohexyl)-methacrylate and the like. From the viewpoint of durability or adhesion, among the above-mentioned hydroxyl-containing monomers, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are suitable. In addition, one type or two or more types of the aforementioned hydroxyl group-containing monomer can be used.

In addition, the monomer unit constituting the aforementioned (meth)acrylic polymer may contain monomers such as a carboxyl group-containing monomer having a reactive functional group, an amine group-containing monomer, and an amide group-containing monomer. From the viewpoint of adhesion under a humid and hot environment, it is better to use these monomers.

When an acrylic adhesive is used as the adhesive composition constituting the first adhesive layer, a (meth)acrylic polymer containing a carboxyl group-containing monomer having a reactive functional group as a monomer unit may be contained. By using the aforementioned carboxyl group-containing monomer, an adhesive layer with excellent adhesion in a humid and hot environment can be obtained. The aforementioned carboxyl group-containing single system is a compound containing a carboxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group.

Specific examples of the aforementioned carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like.

When an acrylic adhesive is used as the adhesive composition constituting the first adhesive layer, it may contain a (meth)acrylic polymer containing an amine group-containing monomer having a reactive functional group as a monomer unit. By using the aforementioned amine group-containing monomer, an adhesive layer with excellent adhesion in a humid and hot environment can be obtained. The aforementioned amine group-containing single system is a compound containing an amine group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group.

Specific examples of the aforementioned amine group-containing monomer include N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, and the like.

When an acrylic adhesive is used as the adhesive composition constituting the first adhesive layer, a (meth)acrylic polymer containing an amide group-containing monomer having a reactive functional group as a monomer unit may be contained. By using the aforementioned amine group-containing monomer, an adhesive layer with excellent adhesion can be obtained. The aforementioned amide group-containing single system is a compound containing an amide group in its structure and a polymerizable unsaturated double bond such as a (meth)acrylic acid group and a vinyl group.

Specific examples of the aforementioned amine group-containing monomer include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, Meth)acrylamide, N-hydroxymethyl-N-propane (meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl( Acrylamine-based monomers such as meth)acrylamide and mercaptoethyl (meth)acrylamide; N-(meth)acryloyl mopholin, N-(meth)acryloyl piperidine, N-(meth)acryloylpyrrolidine and other N-acryloyl heterocyclic monomers; N-vinylpyrrolidone, N-vinyl-ε-caprolactam, etc. containing N-vinyllactamide Department of monomers and so on.

As the monomer unit constituting the aforementioned (meth)acrylic polymer, the blending ratio (total amount) of the aforementioned reactive functional group is preferably 20 in the total monomers constituting the aforementioned (meth)acrylic polymer. % By weight or less, more preferably 10% by weight or less, more preferably 0.01 to 8% by weight, particularly preferably 0.01 to 5% by weight, and most preferably 0.05 to 3% by weight. If it is more than 20% by weight, the number of cross-linking points will increase and the adhesive (layer) will lose its flexibility, and the stress relaxation properties will tend to become poor.

In addition to the monomer having a reactive functional group described above, the monomer unit constituting the aforementioned (meth)acrylic polymer may also be introduced with other comonomers within the range that does not impair the effect of the present invention. The blending ratio is not particularly limited, but in the total monomers constituting the aforementioned (meth)acrylic polymer, it is preferably 30% by weight or less, and it is more preferable not to contain it. If it is more than 30% by weight, especially when a monomer other than (meth)acrylic monomer is used, the reaction point with the film will decrease, and the adhesion tends to decrease.

In the present invention, when the aforementioned (meth)acrylic polymer is used, a weight average molecular weight (Mw) in the range of 1 million to 2.5 million is generally used. When considering durability, especially heat resistance or flexibility, it should be 1.2 million to 2.2 million, preferably 1.4 million to 2 million. If the weight average molecular weight is less than 1 million, when the polymer chains are cross-linked to ensure durability, compared to those with a weight average molecular weight of 1 million or more, the cross-linking points will increase and the adhesive (layer) will be lost Because of its flexibility, it cannot relax the dimensional changes between the outer side of the bend (convex side) and the inner side of the bend (concave side) that are generated between the films during deflection, and the films are prone to breakage. In addition, if the weight average molecular weight is greater than 2.5 million, a large amount of diluting solvent is required to adjust the viscosity required for coating, which increases the cost, which is not good, and the polymer chain of the obtained (meth)acrylic polymer The entanglement with each other will become complicated, and thus the flexibility will be deteriorated, making the film prone to breakage when flexed. In addition, the weight average molecular weight (Mw) refers to a value measured by GPC (Gel Permeation Chromatography) and calculated in terms of polystyrene.

For the production of the (meth)acrylic polymer, known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. In addition, the obtained (meth)acrylic polymer may be any of random copolymers, block copolymers, graft copolymers, and the like.

In the aforementioned solution polymerization, the polymerization solvent can be, for example, ethyl acetate, toluene, etc. As a specific example of solution polymerization, a polymerization initiator can be added under a stream of inert gas such as nitrogen, and it is generally carried out under reaction conditions of about 50 to 70°C for about 5 to 30 hours.

The polymerization initiator, chain transfer agent, emulsifier, etc. used for radical polymerization are not particularly limited and can be appropriately selected and used. In addition, the weight average molecular weight of the (meth)acrylic polymer can be controlled by the usage amount of the polymerization initiator and the chain transfer agent and the reaction conditions, and the usage amount can be appropriately adjusted according to the types of the polymerization initiator and the chain transfer agent.

Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, and 2,2'-azobis[ 2-(5-Methyl-2-imidazolin-2-yl)propane) dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-co Azobis(N,N'-dimethylisobutylamidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (trade name: VA-057, azo initiators of Wako Pure Chemical Industries, Ltd., persulfates of potassium persulfate, ammonium persulfate, etc., bis(2-ethylhexyl)peroxydicarbonate, bis( 4-tertiary butyl cyclohexyl) peroxydicarbonate, di-secondary butyl peroxydicarbonate, tertiary butyl peroxyneodecanoate, tertiary hexyl peroxide trimethyl acetate, peroxide Tertiary butyl trimethylacetate, dilaurel peroxide, di-n-octyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, Bis(4-methylbenzyl) peroxide, dibenzyl peroxide, tertiary butyl perisobutyrate, 1,1-bis(tertiary hexylperoxy) cyclohexane, Peroxide-based initiators such as tertiary butyl hydroperoxide and hydrogen peroxide, combinations of persulfate and sodium bisulfite, peroxide and sodium ascorbate, and other peroxides and reducing agents are combined Redox initiators, etc., but are not limited to them.

The aforementioned polymerization initiators can be used in combination of one or more than two types, but the total content is preferably about 0.005 to 1 part by weight relative to 100 parts by weight of the total monomers constituting the (meth)acrylic polymer. It is about 0.02 to 0.5 parts by weight.

In addition, when chain transfer agents, emulsifiers or reactive emulsifiers used in emulsion polymerization are used, those known in the past can be used as appropriate. In addition, these addition amounts can be appropriately determined within a range that does not impair the effects of the present invention.

＜Crosslinking agent＞ The adhesive composition constituting the first adhesive layer may contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent or a polyfunctional metal chelate compound can be used. Examples of the organic crosslinking agent include isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents. Multifunctional metal chelate is a covalent bond or coordinate bond between a multivalent metal and an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. Examples of the atoms that can be covalently bonded or coordinately bonded in the organic compounds include oxygen atoms, and the organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds. Among them, isocyanate-based crosslinking agents (especially trifunctional isocyanate-based crosslinking agents) are ideal from the standpoint of durability, and peroxide-based crosslinking agents and isocyanate-based crosslinking agents (especially bifunctional The isocyanate-based crosslinking agent) is preferable from the viewpoint of flexibility. Both peroxide-based crosslinking agents and difunctional isocyanate-based crosslinking agents will form soft two-dimensional crosslinks, while trifunctional isocyanate-based crosslinking agents will form relatively strong three-dimensional crosslinks. When flexing, two-dimensional crosslinking, which is a softer crosslink, is more advantageous. However, only two-dimensional cross-linking will lack durability and easily peel off. Therefore, a hybrid cross-linking of two-dimensional cross-linking and three-dimensional cross-linking is preferred. Therefore, a trifunctional isocyanate-based cross-linking agent and peroxide are used in combination. A crosslinking agent or a difunctional isocyanate crosslinking agent is a preferred aspect.

The usage amount of the aforementioned crosslinking agent is preferably 0.01-10 parts by weight, preferably 0.03-2 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer. If it is in the said range, it will be excellent in flexural resistance and it is a preferable aspect. ＜Other additives＞ In addition, the adhesive composition constituting the first adhesive layer may also contain other well-known additives. For example, various silane coupling agents, polyalkylene glycol polyether compounds such as polypropylene glycol, colorants, Pigments and other powders, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, anti- Electrostatic agents (alkali metal salts or ionic liquids of ionic compounds, etc.), inorganic or organic fillers, metal powders, granules, foils, etc. In addition, it is also possible to use a redox system with a reducing agent added within a controllable range.

[Other adhesive layer] The second adhesive layer used in the display device of the present invention can pass through the layered structure volume layer on the other side of the optical film member.

The third adhesive layer used in the display device of the present invention can pass through the area layer touch sensor member on the side of the film sealing layer opposite to the panel member.

In addition, the second adhesive layer, the third adhesive layer, and further other adhesive layers may have the same composition (same adhesive composition) and the same characteristics, or may have different characteristics, and are not particularly limited.

＜Formation of an adhesive layer＞ The plurality of adhesive layers of the present invention are preferably formed from the aforementioned adhesive composition. The method of forming the adhesive layer may be, for example, a method in which the aforementioned adhesive composition is applied to a separation member that has undergone a peeling treatment, and then the polymerization solvent or the like is dried and removed to form an adhesive layer. Moreover, it can also be produced by the method etc. of apply|coating the said adhesive composition on a polarizing film etc., drying and removing a polymerization solvent etc., and forming an adhesive layer on a polarizing film, etc.. In addition, when the adhesive composition is applied, one or more solvents other than the polymerization solvent may be separately added as appropriate.

Polysilicon release liner material should be used for the separated parts that have been stripped. When the adhesive composition of the present invention is coated on the lining material and dried to form an adhesive layer, the method of drying the adhesive may be appropriate depending on the purpose. It is desirable to adopt a method of heating and drying the above-mentioned coated film. The heating and drying temperature, for example, when preparing an acrylic adhesive with (meth)acrylic polymer, it is suitable to be 40~200°C, 50~180°C is preferred, and 70~170°C is particularly preferred. By setting the heating temperature within the above range, an adhesive with excellent adhesive properties can be obtained.

Suitable drying time can be adopted. The drying time mentioned above, for example, when preparing an acrylic adhesive with (meth)acrylic polymer, it is preferably 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, and 10 seconds to 5 minutes are particularly preferred. .

Various methods can be adopted for the coating method of the aforementioned adhesive composition. Specifically, for example, roll coating, touch roll coating, gravure coating, reverse coating, roll brush, spray cloth, dip roll coating, bar coating, knife coating (knife coating), air knife Methods such as coating, curtain coating, lip coating, and extrusion coating using a die coater.

The thickness of the adhesive layer used in the display device of the present invention is preferably 1 to 200 μm, preferably 5 to 150 μm, and more preferably 10 to 100 μm. The adhesive layer can be a single layer or a laminated structure. If it is in the aforementioned range, it will not hinder the deflection, and it is also a preferable aspect from the viewpoint of adhesion (resistance resistance). In addition, when there are a plurality of adhesive layers, all the adhesive layers are preferably within the aforementioned range. The upper limit of the glass transition temperature (Tg) of the adhesive layer used in the laminate for the flexible image display device of the present invention is preferably 0°C or less, preferably -20°C or less, and more preferably -25°C or less. As long as the Tg of the adhesive layer is within the above range, the adhesive layer is not easy to harden even in the fast speed region when flexed, and the stress relaxation is excellent, so that it can be flexible or foldable. Image display device. [Panel component] The panel member may also be provided with a panel base such as an image display panel and a substrate holding it. A sealing member (a film sealing layer, etc.) may also be arranged on the viewing side of the image display panel. The substrate may be one that can hold the image display panel and has appropriate strength and flexibility. A resin sheet etc. can be used for such a board|substrate. The material of the resin sheet is not particularly limited, and can be selected appropriately according to the type of panel.

The image display panel can use a well-known thing. The image display panel can be, for example, an organic electroluminescence (EL: Electro Luminescence) panel. The image display panel is not limited to an organic EL panel, and can also be a liquid crystal panel or an electrophoretic display panel (electronic paper). For example, a bendable liquid crystal panel can be formed by using a flexible substrate such as a resin substrate as a transparent substrate sandwiching the liquid crystal layer.

＜Film Sealing Layer＞ The film sealing layer (TFEE: Thin Film Encapsulation) has the function of preventing the aforementioned image display panel from being exposed to moisture and/or air. The thin-film sealing layer is formed in the form of an inorganic and organic multilayer film formed by alternately laminating a passivation film and a resin film on the light-emitting layer. In addition, the constituent material of the thin film sealing layer may include materials with low moisture permeability, such as inorganic materials such as silicon nitride, silicon oxynitride, carbon oxide, carbon nitride, and aluminum oxide, and resins.

[Touch Sensor Component] The touch sensor can be used, for example, in the field of image display devices. The touch sensor can be, for example, resistive film type, capacitive type, optical type or ultrasonic type, but it is not limited to these.

Capacitive touch sensors generally have a transparent conductive layer. Such a touch sensor can be, for example, a laminate of a transparent conductive layer and a transparent substrate. Examples of the transparent substrate include transparent films.

＜Transparent conductive layer＞ The transparent conductive layer is not particularly limited, and conductive metal oxides, metal nanowires, etc. can be used. The metal oxide may include, for example, indium oxide (ITO: Indium Tin Oxide) containing tin oxide, and tin oxide containing antimony. The transparent conductive layer may also be a conductive pattern made of metal oxide or metal. The shape of the conductive pattern may include a stripe shape, a square shape, a lattice shape, etc., but it is not limited to these.

＜Transparent film＞ As the transparent film, for example, a transparent resin film can be used. The resin constituting the transparent film can include polyester resins (also including polyarylate resins), acetate resins, polyether ether resins, polycarbonate resins, polyamide resins, and polyimide resins. Resins, polyolefin resins, acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, sulfide resins (e.g. polyphenylene sulfide resins) , Polyetheretherketone resin, cellulose resin, epoxy resin, urethane resin, etc. The transparent film may contain one kind of these resins, or two or more kinds. Among these resins, polyester-based resins, polyimide-based resins, and polyether sulfide-based resins are preferred. However, the resin constituting the transparent film is not limited to these resins.

[Protection member] The protective member is laminated on the side of the panel member opposite to the second adhesive layer through the fourth adhesive layer. The protective member is a resin substrate that is attached to the back of the flexible image display panel and functions as a reinforcing plate for reinforcing the mechanical strength, and is used to protect the flexible image display panel from damage or impact, and is formed into a film shape.

[Layered Structure] The laminated structure of the present invention has a panel member. In addition, in the display device, the laminated structure has a layer that is more susceptible to breakage than the window member and the optical film member when it is bent and deformed on the surface on the side of the second adhesive layer described later.

[Display device] The display device of the present invention has: an optical film member, a first adhesive layer, a window member laminated on one side of the optical film member through the first adhesive layer, a second adhesive layer, and a second adhesive layer laminated on the other side of the optical film member The laminated structure, and the display device of the present invention is configured to be bendable.

Fig. 2 is a cross-sectional view showing an embodiment of the display device of the present invention. The display device 100 includes: an optical film member 110, a first adhesive layer 120, a window member 130 laminated on one surface of the optical film member 110 through the first adhesive layer 120, a second adhesive layer 140, and a second adhesive layer 140 laminated on The laminated structure 101 on the other side of the optical film member 110. The laminated structure 101 includes a panel member 150. The display device 100 is configured to be bendable.

Although it is an arbitrary option, the optical film member 110 can be a circularly polarized film laminate 115 in which a retardation film 113 is laminated on a polarizing film 111. The circularly polarizing functional film laminate 115 is used, for example, to generate circularly polarized light or to compensate the viewing angle, etc., in order to prevent the light incident from the viewing side of the polarizing film 111 from being internally reflected and then emitted to the viewing side.

Although it is an arbitrary option, the polarizing film 111 can be a laminate in which the polarizing member 117 and the polarizing member protective film 119 located on at least one side of the polarizing member 117 are laminated.

Although it is an arbitrary option, the polarizer protective film 111 may include acrylic resin.

The layered structure 101 has a layer on the side of the second adhesive layer 140 that is easier to break when deformed by bending than the window member 130 and the optical film member 110.

Although it is an optional option, the laminated structure 101 can be the following: further having a third adhesive layer 160, a film sealing layer 151 is formed on the surface of the panel member 150 on the second adhesive layer 140 side, and the film sealing layer The surface of the 151 opposite to the panel member 150 is laminated with a touch sensor member 170 through the third adhesive layer 160, and a transparent conductive layer is formed on the surface of the touch sensor member 170 opposite to the panel member 150 The transparent conductive layer 171 is laminated on the second adhesive layer 140 in the form of a layer that is easier to break than the window member 130 and the optical film member 110.

Although it is an optional option, it is possible to further have a fourth adhesive layer 180 on the surface of the panel member 150 opposite to the aforementioned third adhesive layer 160, and a protective member 190 is laminated through the fourth adhesive layer 180.

In the display device 100, the following equations (1) and (2) are established between the following strain differences A, A', B, and B', whereby the easily fractured layer and the hard The elongation of the coating is suppressed to a value smaller than the respective elongation at break: the display device 100 is bent at an angle of 180° with the window member 130 facing outward, and the bending is deformed at an angle of 180° When the distance between the parallel and opposite outermost surfaces of the display device 100 in the folded state is 4 mm, the strain in the direction orthogonal to the bending radius generated on one surface of the optical film member 110 and the first surface of the window member 130 1 The difference in strain in the direction perpendicular to the bending radius generated on the surface of the adhesive layer 120 is set to A; The member 110 and the window member 130 are respectively bent at an angle of 180° in a single layer state, and the bending is deformed into a parallel pair of the optical film member 110 and the window member 130 in the state of being bent at an angle of 180° When the distance between the outermost surfaces of the optical film member 110 is 4 mm, the strain in the direction perpendicular to the bending radius direction generated on the outer surface of the optical film member 110 and the direction perpendicular to the bending radius direction generated on the inner surface of the window member 130 The strain difference of is set as A'; the display device 100 is bent at an angle of 180° with the window member 130 facing outward, and the bending is deformed to be parallel to the display device 100 in a state of being bent at an angle of 180° When the distance between the opposing outermost surfaces becomes 4 mm, the strain in the direction orthogonal to the bending radius direction generated on the other surface of the optical film 110 and the sum generated on the surface of the laminated structure 101 facing the second adhesive layer 140 The difference in strain in the direction orthogonal to the bending radius is set to B; the optical film member 110 and the laminated structure 101 are placed in each of the outer and inner sides after bending and deforming in the same manner as after bending and deforming the aforementioned display device. The single-layer state is bent at an angle of 180°, and the bending is deformed into the distance between the parallel and opposite outermost surfaces of the optical film member 110 and the laminated structure 101 in the state of being bent at an angle of 180°. When it becomes 4 mm, the difference between the strain in the direction perpendicular to the bending radius direction generated on the inner surface of the optical film member 110 and the strain in the direction perpendicular to the bending radius direction generated on the outer surface of the laminated structure 101 is set as B'. 0.8＜A/A’＜1.2　　　　・・・・(1) 0＜B/B’＜0.9　　　　・・・・(3)

A is the strain in the direction orthogonal to the direction of the bending radius generated on the outer surface of the optical film member 110 when the first adhesive layer 120 is present between the optical film member 110 and the window member 130 to be bent and deformed. And the difference between the strain in the direction perpendicular to the bending radius direction generated on the inner surface of the window member 130, and A'is when the optical film member 110 and the window member 130 are bent and deformed in a single-layer state , The difference A'between the strain in the direction perpendicular to the bending radius direction generated on the outer surface of the optical film member 110 and the strain in the direction perpendicular to the bending radius direction generated on the inner surface of the window member 130, so the first The harder the adhesive layer 120 is, the smaller the value of A/A' will be. That is, we believe that A/A' will become an indicator of the hardness of the first adhesive layer 120 in the structure of the display device 100. Similarly, the harder the second adhesive layer 140 is, the smaller the value of B/B' will be. That is, we believe that B/B' will become an indicator of the hardness of the second adhesive layer 140 in the structure of the display device 100.

In this regard, the inventors of the present invention found for the first time that the hardness of the multiple adhesive layers contained in a laminated body formed by appropriately selecting plural layers and/or members to be laminated can suppress the laminated body when the laminated body is bent and deformed. The elongation of the layer and/or member with fragile flexural resistance contained therein can inhibit the fracture of the layer and/or member with fragile flexural resistance. Therefore, the first adhesive layer 120 is appropriately selected by using A/A' and B/B' and satisfying the formulas (1) and (2) used to specify the conditions for A/A' and B/B' The hardness of each of the second adhesive layer 140 and the second adhesive layer 140 can suppress the elongation of the layer and the hard coat layer that are easy to break during bending deformation to a value smaller than the respective elongation at break, and can suppress the layer that is easy to break and the hard coat Layer fracture.

Here, in terms of the factors that determine the hardness of the adhesive layer, the shear elastic modulus G'of the adhesive layer is the main controlling factor, and the thickness of the adhesive layer is also a factor. The smaller the thickness of the adhesive layer, the harder the adhesive layer.

Although it is an arbitrary option, the shear elastic modulus G'of the second adhesive layer 140 can be made larger than the shear elastic modulus G'of the first adhesive layer 110. In this regard, the inventors of the present invention found for the first time that in a laminate in which multiple layers and/or members are laminated through multiple layers of adhesive layers, when a certain adhesive layer is hardened, the laminate is laminated on the adhesive layer when the laminate is folded. The strain of the layer or member on the outer side of the layer will shift to the tensile side, and the strain of the layer or member laminated on the inner side of the adhesive layer will shift to the compression side. Moreover, the shear elastic modulus G'of the adhesive layer is the main controlling factor for the hardness of the adhesive layer. Therefore, by making the structure described above, the transparency of the fragile layer generated on the inner side of the second adhesive layer 140 can be further reduced. The tensile strain of the conductive layer 171 or the film sealing layer 151.

Although it is an arbitrary option, the shear elastic modulus G'of the fourth adhesive layer 180 can be made smaller than the shear elastic modulus G'of the second adhesive layer 140 and smaller than the shear elastic modulus G of the third adhesive layer 160 '. When an adhesive layer is softened, the strain of the layer or member laminated on the outer side of the adhesive layer will shift to the compression side, and the strain of the layer or member laminated on the inner side of the adhesive layer will shift to the tensile side. Moreover, the shear elastic modulus G'of the adhesive layer is the main controlling factor for the hardness of the adhesive layer. Therefore, by making the structure described above, the transparency of the fragile layer that is generated on the outside of the fourth adhesive layer 180 can be reduced. The tensile strain of the conductive layer 171 or the film sealing layer 151.

As mentioned above, in a laminate in which multiple layers and/or members are laminated through multiple adhesive layers, when an adhesive layer is hardened, the strain of the layer or member laminated on the outside of the adhesive layer when the laminate is folded It will be displaced to the tensile side, and the strain of the layer or member laminated on the inner side of the adhesive layer will be displaced to the compression side. Therefore, when it is desired to suppress the fracture of the layer fragile to the flexure inside a certain adhesive layer, the hardness of the adhesive layer can be changed to a larger one, and when it is desired to suppress the fracture of the layer fragile to the flexure outside of a certain adhesive layer Just change the hardness of the adhesive layer to a smaller one.

For example, in the design process of the display device, when the fragile layer located inside the first adhesive layer or the second adhesive layer in the laminated structure is broken or is predicted to be broken, the first adhesive layer or the second adhesive layer Changing the hardness of at least one of the adhesive layers to a larger one can suppress the fracture of the easily fractured layer. At this time, among the factors that determine the hardness of the adhesive layer, for example, there are the shear elastic modulus G'of the adhesive layer and the thickness of the adhesive layer. Therefore, the thickness of at least one of the first adhesive layer or the second adhesive layer By changing to a smaller one, or by changing the elastic modulus of at least one of the first adhesive layer or the second adhesive layer to a higher one, the fracture of the easily fractured layer can be suppressed.

Also, at this time, the easily fractured layer of the laminated structure is located outside the third adhesive layer and the fourth adhesive layer, so by changing the hardness of at least one of the third adhesive layer or the fourth adhesive layer to a smaller one , For example, changing the thickness of the third adhesive layer to a larger one, and/or changing the shear elastic modulus G'of at least one of the third adhesive layer or the fourth adhesive layer to a lower one can prevent easy fracture The fracture of the layer.

The display device shown in FIG. 3 is basically the same as that shown in FIG. 2, except for the following point: the layer that is more breakable than the window member 130 and the optical film member 110 is the transparent conductive layer 171 in the display device of FIG. The transparent conductive layer 171 is formed on the surface of the touch sensor member 170 laminated between the second adhesive layer 140 and the panel member 150 on the opposite side of the panel member 150. In contrast, compared to the window member 130 and The more easily broken layer of the optical film member 110 is the film sealing layer 151 formed on the surface of the panel member 150 on the side of the second adhesive layer 140 in the display device of FIG. 4.

[Substrate laminate] The substrate laminate 103 of the present invention is used for display devices, and the layer of the substrate laminate 103 that is more easily broken than the window member and the optical film member is a transparent conductive layer, and the transparent conductive layer is formed on the second adhesive layer. The surface of the touch sensor member between the layer and the panel member on the side opposite to the panel member; and the substrate laminate 103 has: an optical film member; the window member is through the first adhesive layered layer On one side of the optical film member; and the transparent conductive layer is laminated on the other side of the optical film member through the second adhesive layer.

Example The following examples are used to further illustrate the display device and substrate laminate of the present invention. In addition, the display device and the substrate laminate of the present invention are not limited by these embodiments. [Example 1]

[Polarizer] As a thermoplastic resin base material, an amorphous polyethylene terephthalate (hereinafter also referred to as "PET") (IPA copolymer PET) film (thickness: 100μm) with 7 mol% isophthalic acid units is prepared, and The surface is treated with corona (58W/m2/min). On the other hand, it is prepared to add 1% by weight of acetyl acetyl modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: GOHSEFIMER Z200 (average degree of polymerization: 1200, degree of saponification: 98.5 mol%) Acetyl acetylation degree: 5 mol%) PVA (polymerization degree 4200, saponification degree 99.2%), and prepare a coating solution of a PVA aqueous solution containing 5.5% by weight of PVA-based resin so that the film thickness after drying becomes After coating at 12 μm and drying with hot air for 10 minutes in an atmosphere of 60° C., a laminate with a layer of PVA-based resin on the substrate was produced.

Then, the laminated body was first stretched 1.8 times at the free end at 130°C in air (air-assisted stretching) to produce a stretched laminated body. Next, the stretched laminate was immersed in a boric acid insoluble aqueous solution at a liquid temperature of 30° C. for 30 seconds to perform an insolubilization step for the PVA layer in which the PVA molecules contained in the stretched laminate were oriented. The boric acid insoluble aqueous solution in this step is to make the content of boric acid 3 parts by weight relative to 100 parts by weight of water. And by dyeing the stretched layered body, a colored layered body is generated. In the colored laminate system, the single transmittance of the PVA layer that constitutes the final polarizer becomes 40~44%, and the stretch laminate is immersed in a dyeing solution containing iodine and potassium iodide at a liquid temperature of 30°C for any time. This is made by dyeing the PVA layer contained in the stretch laminate with iodine. In this step, the dyeing solution uses water as the solvent, and the iodine concentration is set in the range of 0.1 to 0.4% by weight, and the potassium iodide concentration is set in the range of 0.7 to 2.8% by weight. The concentration ratio of iodine to potassium iodide is 1:7. Next, by immersing the colored laminate in a boric acid cross-linking aqueous solution at 30° C. for 60 seconds, a step of cross-linking the PVA molecules of the iodine-adsorbed PVA layer is performed. The boric acid cross-linking aqueous solution in this step is such that the content of boric acid is 3 parts by weight relative to 100 parts by weight of water, and the content of potassium iodide is 3 parts by weight relative to 100 parts by weight of water.

Then, the resulting colored laminate was stretched to 3.05 times in the same direction as the previous stretch in the air at a stretching temperature of 70°C in a boric acid aqueous solution (boric acid water stretching) to obtain an optical film with a final stretch magnification of 5.50 times Layered body. The optical film laminate was taken out from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with an aqueous solution whose potassium iodide content was 4 parts by weight with respect to 100 parts by weight of water. The cleaned optical film laminate was dried by a drying step using warm air at 60°C. The thickness of the polarizer contained in the obtained optical film laminate was 5 µm.

[Polarizer protective film] The polarizer protective film is formed by extruding methacrylic resin pellets having glutarimide ring units into a film shape and then stretching. The polarizer protective film has a thickness of 40 µm and an acrylic film with a ^{moisture permeability of 160 g/m 2.}

[Polarizing Film] Next, the polarizer and the polarizer protective film are bonded together using the adhesive shown below to prepare a polarizing film.

，日本化藥公司製The aforementioned adhesive (active energy ray hardening adhesive) is prepared by mixing the components according to the blending table described in Table 1, and stirring at 50°C for 1 hour to prepare the adhesive (active energy ray hardening adhesive A) . The numerical value in the table is the blending amount (addition amount), which represents the solid content or the solid content ratio (weight basis), and represents the weight% when the total composition is 100% by weight. The ingredients used are as follows. HEAA: hydroxyethyl acrylamide M-220: ARONIX M-220, tripropylene glycol diacrylate), Toagosei Co., Ltd. ACMO: acryloyl mopholine AAEM: 2-acetyl acetoxy ethyl methyl Acrylate, manufactured by Nippon Synthetic Chemical Co., Ltd. UP-1190: ARUFON UP-1190, manufactured by Toagosei Co., Ltd. IRG907: IRGACURE907, 2-methyl-1-(4-methylsulfanylphenyl)-2-mopholin-1 -Ketone, DETX-S manufactured by BASF: KAYACURE DETX-S, diethyl 9-oxysulfur 𠮿

, Manufactured by Nippon Kayaku Co., Ltd.

[Table 1]

In addition, in the examples and comparative examples using the adhesive, the polarizer protective film and the polarizer were laminated through the adhesive, and then ultraviolet rays were irradiated to harden the adhesive to form an adhesive layer. Ultraviolet rays were irradiated using a gallium-filled metal halide lamp (manufactured by Fusion UV Systems, Inc., trade name "Light HAMMER10", valve: V valve, peak illuminance: 1600mW/cm ² , cumulative irradiation amount 1000/mJ/cm ² ( Wavelength 380~440nm).

[Retardation film] The retardation film (1/4 wavelength retardation plate) of the present embodiment is composed of two layers of a retardation layer for a quarter wavelength plate and a retardation layer for a 1/2 wavelength plate with oriented and immobilized liquid crystal material. The retardation film. Specifically, it is manufactured according to the following procedures.

(Liquid crystal material) The material used to form the retardation layer for the 1/2-wavelength plate and the retardation layer for the quarter-wavelength plate is a polymerizable liquid crystal material exhibiting a nematic liquid crystal phase (manufactured by BASF Corporation: trade name Paliocolor LC242). A photopolymerization initiator (manufactured by BASF Corporation: trade name Irgacure 907) for this polymerizable liquid crystal material was dissolved in toluene. In addition, in order to improve the coating properties, the MEGAFACE series manufactured by DIC is prepared by adding about 0.1 to 0.5% of the thickness of the liquid crystal to prepare a liquid crystal coating liquid. After coating the liquid crystal coating liquid on an orientation substrate with a bar coater, it was heated and dried at 90° C. for 2 minutes, and then cured by ultraviolet rays in a nitrogen atmosphere to fix the orientation. The base material is, for example, PET, which can transfer the liquid crystal coating layer afterwards. In order to improve the coating properties, the MEGAFACE series fluorine-based polymer made by DIC is added about 0.1% to 0.5% according to the thickness of the liquid crystal layer, and MIBK (methyl isobutyl ketone), cyclohexanone or MIBK and cyclohexanone are used. The mixed solvent of hexanone was dissolved to a solid content concentration of 25% to prepare a coating liquid. The coating solution was applied to the substrate with a wire rod, and after a drying step set to 65°C for 3 minutes, the coating was cured by ultraviolet rays in a nitrogen atmosphere to fix the orientation. The base material is, for example, PET, which can transfer the liquid crystal coating layer afterwards.

(Manufacturing steps) The manufacturing steps of this embodiment will be described with reference to FIG. 4. In this manufacturing step 20, the base material 14 is supplied by a roller, and the base material 14 is supplied from the supply reel 21. In the manufacturing step 20, the coating liquid of the ultraviolet curable resin 10 is applied to the substrate 14 with the die 22. In this manufacturing step 20, the roll plate 30 is a cylindrical shaping mold, and its peripheral surface is formed with the uneven shape of the alignment film for the quarter-wavelength plate with respect to the quarter-wave retardation plate. In the manufacturing step 20, the substrate 14 coated with the ultraviolet curable resin is pressed against the peripheral side surface of the roll plate 30 with the pressure roller 24, and the ultraviolet irradiation device 25 composed of a high-pressure mercury lamp is irradiated with ultraviolet rays to make the ultraviolet curable resin hardening. Thereby, the manufacturing step 20 transfers the concave-convex shape formed on the peripheral side surface of the roll plate 30 to the base material 14 at 75° with respect to the MD direction. After that, the base material 14 and the cured ultraviolet curable resin 10 are integrally peeled from the roll plate 30 by the peeling roller 26, and then the liquid crystal material is applied by the die head 29. After that, the ultraviolet irradiation device 27 is used to irradiate ultraviolet rays to harden the liquid crystal material, and the structure of the retardation layer for the quarter-wave plate is formed by these procedures.

Next, in this step 20, the base material 14 is transported to the die 32 by the transport roller 31, and the ultraviolet curable resin 12 is coated on the retardation layer for the quarter-wave plate of the base material 14 by the die 32. Cloth liquid. In this manufacturing step 20, the roll plate 40 is a cylindrical shaping mold, and its peripheral surface is formed with a concave-convex shape of the oriented film for a 1/2-wavelength plate with respect to a quarter-wave retardation plate. In the manufacturing step 20, the substrate 14 coated with the ultraviolet curable resin is pressed against the peripheral side of the roll plate 40 with the pressure roller 34, and the ultraviolet irradiation device 35 composed of a high-pressure mercury lamp is used to irradiate the ultraviolet curable resin. hardening. Thereby, the manufacturing step 20 transfers the uneven shape formed on the peripheral side surface of the roll plate 40 to the base material 14 at 15° with respect to the MD direction. After that, the base material 14 and the cured ultraviolet curable resin 12 are integrally peeled from the roll plate 40 by the peeling roller 36, and then the liquid crystal material is applied by the die 39. After that, the liquid crystal material is irradiated with ultraviolet light by the ultraviolet irradiation device 37, and the structure of the retardation layer for the 1/2-wavelength plate is formed by these procedures, and the retardation layer for the quarter-wavelength plate, 1 A retardation film with a thickness of 7μm composed of two retardation layers for /2-wavelength plates.

[Optical film member (Layered body of circularly polarizing function film)] Using the above-mentioned adhesive, the retardation film and the polarizing film obtained by the above-mentioned procedure are continuously laminated by a roll to roll method, and the axis angle between the slow axis and the absorption axis is 45° to produce a laminated film (round Polarizing function film laminate).

[First Adhesive Layer] The adhesive layer constituting the first adhesive layer of this example was produced by the following method. ＜Preparation of acrylic oligomer＞ ＜oligomer A＞ As monomer components, 60 parts by weight of dicyclopentyl methacrylate (DCPMA) and 40 parts by weight of methyl methacrylate (MMA), 3.5 parts by weight of α-thioglycerin as a chain transfer agent, and toluene as a polymerization solvent are mixed 100 parts by weight, and stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was added, and after reacting at 70°C for 2 hours, the temperature was raised to 80°C and reacted for 2 hours. After that, the reaction solution was heated to 130°C, and toluene, chain transfer agent, and unreacted monomer were dried and removed to obtain a solid acrylic oligomer (oligomer A). The weight average molecular weight of oligomer A is 5100, and the glass transition temperature (Tg) is 130°C.

＜oligomer B＞ The monomer components were changed to 60 parts by weight of dicyclohexyl methacrylate (CHMA) and 40 parts by weight of butyl methacrylate (BMA), except that the solid acrylic oligomer was obtained in the same manner as the preparation of oligomer A. Polymer (oligomer B). The weight average molecular weight of oligomer B is 5000, and the glass transition temperature (Tg) is 44°C.

(Polymerized prepolymer) As a monomer component for prepolymer formation, 43 parts by weight of lauryl acrylate (LA), 44 parts by weight of 2-ethylhexyl acrylate (2EHA), 6 parts by weight of 4-hydroxybutyl acrylate (4HBA), and N -7 parts by weight of vinyl-2-pyrrolidone (NVP) and 0.015 parts by weight of "IRGACURE 184" manufactured by BASF as a photopolymerization initiator, and irradiated with ultraviolet rays for polymerization to obtain a prepolymer composition (polymerization rate; About 10%).

(Preparation of adhesive composition) To 100 parts by weight of the above-mentioned prepolymer composition, add 0.07 parts by weight of 1,6-hexanediol diacrylate (HDDA), the above-mentioned oligomer A: 1 part by weight, and a silane coupling agent ("KBM403" manufactured by Shin-Etsu Chemical) ): After 0.3 parts by weight as a post-addition component, these are uniformly mixed to prepare an adhesive composition. Hereinafter, this adhesive composition is also referred to as adhesive composition 1.

(Making the adhesive sheet) A 75µm-thick polyethylene terephthalate (PET) film ("DIAFOIL MRF75" manufactured by Mitsubishi Chemical Co.) with a silicone-based release layer on the surface is used as the base material (double-weight release film) ), the above-mentioned photocurable adhesive composition is applied on the substrate so that the thickness becomes 50 µm to form a coating layer. A 75-µm-thick PET film ("Diafoil MRE75" manufactured by Mitsubishi Chemical Co.), which has been treated with silicone peeling on one side, was attached to the coating layer as a cover sheet (also a light peeling film). The layered body was irradiated with ultraviolet rays by adjusting the position from the cover sheet side so that the irradiation intensity of the irradiation surface directly under the lamp became 5mW/cm ² and photocured to form an adhesive sheet with a thickness of 50 µm. Hereinafter, the adhesive layer of any thickness of the adhesive composition 1 made by the same method is also referred to as the adhesive layer 1.

[Second Adhesive Layer] The adhesive layer constituting the second adhesive layer of this example was produced by the following method. <Preparation of (meth)acrylic polymer A1> A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a cooler was fed with a monomer mixture containing 99 parts by weight of butyl acrylate (BA) and 1 part by weight of 4-hydroxybutyl acrylate (HBA).

In addition, 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator was fed with ethyl acetate with respect to 100 parts by weight of the aforementioned monomer mixture (solid content), and nitrogen was introduced while stirring slowly. After the nitrogen substitution, the liquid temperature in the flask was maintained at around 55°C to perform the polymerization reaction for 7 hours. After that, ethyl acetate was added to the obtained reaction liquid to prepare a solution of (meth)acrylic polymer A1 whose solid content concentration was adjusted to 30% and a weight average molecular weight of 1.6 million.

<Preparation of acrylic adhesive composition> With respect to 100 parts by weight of the solid content of the obtained (meth)acrylic polymer A1 solution, an isocyanate-based crosslinking agent (trade name: TAKENATE D110N, trimethylolpropane diisocyanate stubble ester, Mitsui Chemicals Co., Ltd. ) System) 0.1 parts by weight, peroxide-based crosslinking agent benzyl peroxide (trade name: NYPER BMT, manufactured by Nippon Oil & Fat Co., Ltd.) 0.3 parts by weight, silane coupling agent (trade name: KBM403, Shin-Etsu Chemical Industrial Co., Ltd.) 0.08 parts by weight to prepare an acrylic adhesive composition. Hereinafter, this adhesive composition is also referred to as adhesive composition 2.

＜Making Adhesive Sheets＞ The aforementioned acrylic adhesive composition was uniformly coated on a 38μm thick polyethylene terephthalate film (PET film, transparent substrate, separation The surface of the part) is dried in an air circulation constant temperature oven at 155°C for 2 minutes, and an adhesive layer (the third adhesive layer) with a thickness of 20 μm is formed on the surface of the substrate. On the coating layer, a polyethylene terephthalate film (PET film, transparent substrate, separator) with a thickness of 38 µm, which has been peeled off by silicone on one side, is attached as a cover sheet (and a light release film) . Hereinafter, the adhesive layer of any thickness of the adhesive composition 2 made by the same method is also referred to as the adhesive layer 2.

[3rd Adhesive Layer] The adhesive layer constituting the third adhesive layer of this example was produced by the following method.

Put 2-ethylhexyl acrylate (2EHA) as a monomer component in a separate flask: 63 parts by weight, N-vinyl-2-pyrrolidone (NVP): 15 parts by weight, methyl methacrylate ( MMA): 9 parts by weight, 2-hydroxyethyl acrylate (HEA): 13 parts by weight, 2,2'-azobisisobutyronitrile as polymerization initiator: 0.2 parts by weight, and ethyl acetate 133 as polymerization solvent Part by weight, stirring for 1 hour while introducing nitrogen. After removing oxygen in the polymerization system in the above manner, the temperature was raised to 65° C. to react for 10 hours, and then ethyl acetate was added to obtain an acrylic polymer solution with a solid content of 30% by weight. In addition, the weight average molecular weight of the acrylic polymer in the acrylic polymer solution was 800,000.

Next, to the acrylic polymer solution, an isocyanate-based crosslinking agent (trade name "TAKENATE D110N", (Manufactured by Mitsui Chemicals Co.), and mixed them to prepare an adhesive composition. Hereinafter, this adhesive composition is also referred to as an adhesive composition 4. ＜Making Adhesive Sheets＞ Coat the surface of a 38μm thick polyethylene terephthalate film (PET film, transparent substrate, separator) treated with a silicone-based release agent uniformly by a jet coater, and then apply it to the PET A coating layer was formed on the substrate, and the resultant was put into an oven to dry the coating layer at 130° C. for 3 minutes to form an adhesive sheet having an adhesive layer with a thickness of 15 μm on one side of the PET substrate. On the coating layer, a polyethylene terephthalate film (PET film, transparent substrate, separator) with a thickness of 38 µm, which has been peeled off by silicone on one side, is attached as a cover sheet (and a light release film) . Hereinafter, the adhesive layer of any thickness of the adhesive composition 4 made by the same method is also referred to as the adhesive layer 4.

[4th Adhesive Layer] Except for the thickness of 25 µm, the adhesive layer constituting the fourth adhesive layer of this example was fabricated under the same conditions as the first adhesive layer.

[Window widget] As a window member, a transparent polyimide film (manufactured by KOLON Corporation, product name "C_50", thickness 50µm) as a window film is used for single-sided design (hereinafter, the window film is also referred to as "window film 1"). Those with acrylic hard coat (thickness 10µm).

The hard coat layer is formed using a coating agent for hard coat layer. More specifically, first, after coating the coating agent on one side of the transparent polyimide film to form a coating layer, the coating layer and the transparent polyimide film are heated together at 90° C. for 2 minutes. Next, a high-pressure mercury lamp was used to ^{irradiate the coating layer with ultraviolet rays at a cumulative light amount of 300 mJ/cm 2} to form a hard coat layer. Create a window component through the above procedure.

In addition, the coating agent for the hard coat layer is mixed with 100 parts by mass of a polyfunctional acrylate (manufactured by Aica Kogyo Company, Limited, product name "Z-850-16") as a base resin, and a leveling agent (manufactured by DIC Corporation, a product Name: GRANDIC PC-4100) 5 parts by mass and 3 parts by mass of a photopolymerization initiator (manufactured by Ciba Japan, trade name: IRGACURE 907), diluted with methyl isobutyl ketone to a solid content concentration of 50% by mass. .

[Touch Sensor Component] As a transparent resin substrate, a cycloolefin-based resin substrate ("ZEONOR" made by ZEON, Japan, with a thickness of 25 µm, and an in-plane birefringence of 0.0001) was prepared.

Next, apply the diluent of the hard-coating composition composed of binder resin on the transparent resin substrate, and coat the diluent of the hard-coating composition containing the binder resin and a plurality of particles on the underside of the transparent resin substrate After drying the liquid, both sides are irradiated with ultraviolet rays to harden the hard coating composition. As a result, a particle-free first hardened resin layer (thickness 1 µm) was formed on the upper surface of the transparent resin substrate, and a second hardened resin layer (thickness 1 µm) containing particles was formed on the underside of the transparent resin substrate.

In addition, cross-linked acrylic and styrene resin particles ("SSX105" manufactured by Sekisui Plastics Co., Ltd., diameter 3 µm) were used as the particle system. A urethane-based polyfunctional polyacrylate (manufactured by DIC Corporation, "UNIDIC") is used as the binder resin.

Next, a diluent of an optical adjustment composition containing zirconia particles and ultraviolet curable resin ("OPSTAR Z7412" made by JSR, refractive index 1.62) was coated on the top of the first cured resin layer, and dried at 80°C for 3 After minutes, irradiate ultraviolet light. As a result, an optical adjustment layer (thickness 0.1 µm) is formed on the first hardened resin layer.

Then, an ITO layer (thickness 40nm) is formed on the top of the optical adjustment layer by sputtering, which is an amorphous transparent conductive layer.

Thereby, an amorphous transparent conductive film including a second cured resin layer, a transparent resin base material, a first cured resin layer, an optical adjustment layer, and an amorphous transparent conductive layer in this order was produced.

Next, the obtained amorphous transparent conductive film was heated at 130°C for 90 minutes to crystallize the ITO layer.

[Panel component] As the base of the panel, prepare a polyimide resin film ("UPILEX" made by Ube Industries Co., Ltd., thickness 50µm) using BPDA (biphenyltetracarboxylic dianhydride) as a raw material.

Next, an ITO layer (thickness: 40 nm), which is an amorphous transparent conductive layer, is formed on the top of the polyimide-based resin film by sputtering.

Next, the obtained amorphous transparent conductive film was heated at 130°C for 90 minutes to crystallize the ITO layer.

Then, the obtained ITO layer and the transparent conductive film with ITO layer are used as substitutes for the film sealing layer and the panel member, respectively. Hereinafter, the ITO layer as a substitute for the thin film sealing layer is also referred to as "the ITO layer replacing the thin film sealing layer" or the "replacement ITO layer".

[Protection member] The protective member of this embodiment uses a polyimide resin base material ("UPILEX" manufactured by Ube Industries Co., Ltd., thickness 25 µm) using BPDA (biphenyltetracarboxylic dianhydride) as a raw material.

Various evaluations were performed for each member, layer, and film obtained in the following manner. Tables 2-1~2-3 show the characteristics of each adhesive layer, hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer.

[Example 2] The following adhesive layer was used as the adhesive layer constituting the second adhesive layer, and the display device and the substrate laminate were fabricated as follows, except that the components, layers, films, and laminates were fabricated and fabricated under the same conditions as in Example 1. And conduct various assessments in the following manner. Tables 2-1~2-3 show the characteristics of each adhesive layer, hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer.

The adhesive layer constituting the second adhesive layer of this example was produced by the following method. <Preparation of (meth)acrylic polymer A3> When the liquid temperature in the flask is maintained at around 55°C for 7 hours, the polymerization reaction is carried out so that the blending ratio (weight ratio) of ethyl acetate and toluene becomes 95/5. The (meth)acrylic polymer A1 was carried out in the same manner. <Preparation of acrylic adhesive composition> With respect to 100 parts by weight of the solid content of the obtained (meth)acrylic polymer A1 solution, trimethylolpropane/toluene diisocyanate, manufactured by Japan Polyurethane Industry Co., Ltd., trade name: CORONATE L) 0.15 parts by weight and A silane coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) was 0.08 parts by weight to prepare an acrylic adhesive composition. Hereinafter, this adhesive composition is also referred to as an adhesive composition 3.

＜Making Adhesive Sheets＞ The aforementioned acrylic adhesive composition was uniformly coated on a 38μm thick polyethylene terephthalate film (PET film, transparent substrate, separation The surface of the part) is dried in an air circulation constant temperature oven at 155°C for 2 minutes, and an adhesive layer (the second adhesive layer) with a thickness of 15 μm is formed on the surface of the substrate. On the coating layer, a polyethylene terephthalate film (PET film, transparent substrate, separator) with a thickness of 38 µm, which has been peeled off by silicone on one side, is attached as a cover sheet (and a light release film) . Hereinafter, the adhesive layer of any thickness of the adhesive composition 3 made by the same method is also referred to as the adhesive layer 3.

[Example 3] The adhesive layer 4 was used as the adhesive layer constituting the second adhesive layer, and the display device and the substrate laminate were fabricated in the following manner, except that the components, layers, films, and laminates were fabricated and fabricated under the same conditions as in Example 1. , And conduct various evaluations in the following manner. Tables 2-1~2-3 show the characteristics of each adhesive layer, hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer.

The display device and substrate laminate of this example were produced in the following method.

The adhesive layer is transferred from the release film to one of the members that sandwich each adhesive layer, and each member is laminated by sandwiching the adhesive layer and then pressed with a hand ink roller. A rectangular sample having a width of 30 mm and a length of 100 mm was cut out from the obtained laminate, and each member was laminated and laminated to obtain an evaluation sample.

[Examples 4, 5, 7, 8, 10, 11, 18, Comparative Examples 4, 6, 8, 9] Change the combination of the types of adhesive layers (adhesive layers 1 to 4) that constitute the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer as shown in Tables 2-1 to 2-3, except Otherwise, various members, layers, films, and laminates were manufactured and produced under the same conditions as in Example 1, and various evaluations were performed in the following manner. Tables 2-1~2-3 show the characteristics of each adhesive layer, hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer.

[Examples 16, 17] Change the combination of the types of adhesive layers (adhesive layers 1 to 4) that constitute the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer as shown in Tables 2-1 to 2-3, and Except that the thickness of the first adhesive layer was 25 μm, each member, layer, film, and laminate were manufactured and produced under the same conditions as in Example 1, and various evaluations were performed as follows. Tables 2-1~2-3 show the characteristics of each adhesive layer, hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer.

[Examples 6, 9, 12-15, comparative examples 1, 2, 3, 5, 7, 10] Change the combination of the types of adhesive layers (adhesive layers 1 to 4) that constitute the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer as shown in Tables 2-1 to 2-3, except Otherwise, various members, layers, films, laminates, display devices, and substrate laminates were manufactured and produced under the same conditions as in Example 3, and various evaluations were performed in the following manner. Tables 2-1~2-3 show the characteristics of each adhesive layer, hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer.

[Examples 19-21, Comparative Example 11] Change the combination of the types of adhesive layers (adhesive layers 1 to 4) that constitute the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer as shown in Tables 2-1 to 2-3, and The transparent polyimide film made by DU PONT-TORAY CO., LTD. and the product name "KAPTON (registered trademark) H type" is used as the window film as the window member (hereinafter the window film is also referred to as "window film 2 "), except that each member, layer, film, and laminate were manufactured and produced under the same conditions as in Example 1, and various evaluations were performed in the following manner. Tables 2-1~2-3 show the characteristics of each adhesive layer, hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer.

[Assessment] (Measure the thickness) The thickness of the polarizer, polarizer protective film, retardation film, each adhesive layer, transparent film, window film, and protective member is measured using a dial gauge (manufactured by Mitutoyo Corporation). In addition, the thickness of the ITO layer and the replacement ITO layer is measured based on the image taken with a transmission electron microscope (TEM). (Measure the shear elastic modulus G’ of the adhesive layer) The separator was peeled off from the adhesive sheets of the respective examples and comparative examples, and a plurality of adhesive sheets were laminated to produce a test sample with a thickness of about 1.5 mm. The test sample was punched into a disc shape with a diameter of 7.9mm and clamped into a parallel plate. Then, using the "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific, the dynamic viscoelasticity was measured under the following conditions, and the measurement As a result, the shear elastic modulus G'is read.

(Measurement conditions) Deformation mode: twist Measuring temperature: -40℃~150℃ Heating rate: 5℃/min Measurement frequency: 1Hz

(Measure strain and stress) Self-touch sensor substrate film, panel member replacement base film, and protective member film, and the resulting window film, polarizer, polarizer protective film, adhesive layer 1, adhesive layer 2, 3, and adhesive layer 4 Cut out a sample with a width of 10mm and a length of 100mm. Each of the obtained samples was set on a tensile tester (product name "Autograph AG-IS" manufactured by Shimadzu Corporation), and the strain and stress at the time of stretching at 200 mm/min were measured to obtain a strain-stress curve. The stress is obtained by converting the thickness and width into Pa units. In addition, each adhesive layer is formed by stacking a plurality of adhesive layers to form an adhesive layer with a thickness of 100 µm.

In addition, when it is difficult to make an adhesive layer with a thickness of 100 µm, the strain-stress curve can also be obtained by the following method. 1. Calculate the strain-stress curve for a sample in advance according to the above method, and divide the curve by the tensile modulus of elasticity calculated from the slope of the curve with a strain in the range of 0.05% to 0.25%, thereby making a standardized Strain-stress curve. 2. Measure with the above method to obtain the shear elastic modulus G'of the sample to be measured. 3. Measure the composition of the sample to be measured and find the Parsons ratio ν. 4. The tensile elastic modulus E'and the shear elastic modulus G'form the relationship E'=2G'(1+ν), so E is calculated from the G'and ν measured in 2. and 3. '. 5. By multiplying the normalized strain-stress curve created in 1. above by the tensile elastic modulus E'obtained in 4. above, the strain-stress curve of the sample to be measured can be obtained.

(Simulate the difference in strain in the direction orthogonal to the bending radius) Based on the obtained strain-stress curve of each member and film, the strain in the direction orthogonal to the bending radius direction of each member, layer, and film when bending deformation of each example and each comparative example was obtained by simulation, and A /A', B/B', 1.7A/A'-0.15. The results are shown in Tables 2-1~2-3.

＜Computer simulation software＞ The simulation software system uses Marc made by MSC Software, which is a nonlinear finite element analysis software.

＜Model＞ 1. Layer composition The layer structure of the model is the same as the cross-sectional structure of the display device of the embodiment of FIG. 12. 2. Model size The length was set to 100 mm, and the thickness was set to the total thickness of each member of the cross-sectional configuration shown in FIG. 12, and a grid was formed in two dimensions of thickness and length. 3. Bending method As shown in Figure 5, set a curve with a length of 48mm at both ends, and fix the 10mm end of the grid to the curve (rigid model), rotate the curve on the left by 180°, and make the outermost surface of the grid the outer side Bend. The bending diameter is set to be 4 mm between the parallel and opposite outermost surfaces of the grid when the curve on the left is rotated by 180°. 4. Enter the physical value of each layer Regarding window films, polarizer protective films, polarizers, transparent resin substrates for touch sensor components, alternative transparent resin substrates for panel components, and protective components), the strain-stress curve data of the tensile test of each component The strain and stress are respectively converted into true strain (ln (strain+1), true stress (stress (strain+1)), and enter the type as signed_eq_mechanical_Strain in the table. The material properties of this part of the grid are set Set the type to sub-elastic, and select the stress-strain curve of the material from the table.

此處，γ=ε+1，f係標稱應力，ε係標稱應變。For the adhesive layer, first fit the strain-stress curve data of the tensile test with the following Mooney-Rivlin formula, and calculate the coefficients C10, C01, and C11. Then, set the type of material properties of this part of the grid to Mooney, and input the calculated coefficients C10, C01, and C11.

Here, γ=ε+1, f is the nominal stress, and ε is the nominal strain.

Regarding the retardation film, the type of the material properties of this part of the mesh is set to isotropic elasto-plasticity, and the laminate of the retardation film, polarizer and polarizer protective film of the optical film member obtained in the tensile test is obtained The difference between the strain-test force curve data and the strain-test force curve data of the laminate of the polarizer and polarizer protective film obtained in the tensile test, and the difference obtained from the obtained difference is equivalent to the strain of the retardation film- Divide the value of the test force curve by the cross-sectional area (width×thickness) of the retardation film, and calculate the slope of the curve corresponding to the strain-stress curve of the retardation film in the range of 0.05% to 0.25%. Enter this as the modulus of elasticity of the retardation film.

For the ITO layer, the alternative ITO layer, and the hard coat layer, the type of material properties of this part of the mesh is also set to isotropic elasto-plasticity, and based on the attachment of the touch sensor component obtained in the tensile test. The difference between the strain-test force curve of the transparent resin substrate of the ITO layer and the strain-test force curve of the transparent resin substrate of the touch sensor component, and the difference between the panel component obtained in the tensile test and the replacement ITO layer The difference between the strain-test force curve of the substitute transparent resin substrate and the strain-test force curve of the substitute transparent resin substrate of the panel member, the strain-test force curve of the hard-coated window film obtained in the tensile test and The difference between the strain-test force curve of the window film is calculated and inputted separately.

<Simulation results> For each member of each example and each comparative example, the strain (Elastic Strain in Preferred Sys) in the direction orthogonal to the bending radius direction of the deflection portion was calculated (see FIG. 6). For Comparative Example 1 and Examples 9 to 11, Examples 28, 4, 8, and 11, Examples 8 and 14 to 16, and Examples 17 to 20, the direction orthogonal to the bending radius direction of the flexure was calculated The distribution of strain in the stacking direction is shown in Figure 8~Figure 11.

In addition, for the hard coat, polarizer protective film, ITO layer, and ITO layer of the replacement film sealing layer of each embodiment and each comparative example, the calculated and deflection part are listed in Tables 2-1~2-3 Whether the value of the outermost layer of the strain in the direction orthogonal to the bending radius and the elongation of each layer and film is lower than the elongation at break.

In addition, for each example and each comparative example, A/A', 1.7 calculated from the calculated strain in the direction orthogonal to the bending radius direction of the flexure are listed in Tables 2-1 to 2-3 The values of A/A'-0.15-B/B' and B/B'. In addition, a graph showing the relationship between A/A' and B/B is shown in FIG. 11.

(Assessment of rupture) Regarding the samples of the display devices of the substitutes obtained in Examples 4, 8, 11, 14-18, 20, 24 to 26, and Comparative Examples 1, 2, and 4, confirm whether there is a hard coat layer or a polarizer when bending The protective film, the ITO layer, and the ITO layer that replaced the film sealing layer were cracked.

Specifically, as shown in Figure 12, the display device is bent 180 degrees and a glass plate is used to press the outside of the bent display device, and a 4mm plate is inserted between the glass plates to make the display device parallel to the maximum The flexural state was maintained so that the distance between the surfaces became 4mm, and the rupture of each layer and film was evaluated. The bending diameter is the same as the simulated model, and the distance between the parallel and opposite outermost surfaces of the display device when the display device is bent at an angle of 180° is 4 mm.

Regarding the ITO layer and the ITO layer that replaces the thin-film sealing layer, whether the resistance value of the ITO layer increases after flexing is used to evaluate the occurrence of cracking. The resistance value is a conductive tape (short tab terminal) attached to the surface of the ITO layer, and it is arranged so that the resistance can be measured from the outside of the display device, and the resistance value is measured by a measuring device. The ITO layer uses a sheet resistance of 50Ω/□, and the resistance value between the short tab terminals before deflection is about 165Ω, and the resistance value in the deflection state is 1.1 times or more than the resistance value before deflection The person assessed that there was a rupture.

For the hard coat and polarizer protective film, the occurrence of cracks can be evaluated by microscopic observation or cross-sectional SEM observation after deflection.

The rupture evaluation results of each example and each comparative example are listed in Tables 2-1 to 2-3.

(Calculate the elongation at break) Regarding the elongation at break of the polarizer protective film, the elongation at break was calculated as follows. First, perform the same flexure test as the flexure test used for the above-mentioned evaluation of the occurrence of cracks after changing the bending diameter, and confirm the bending diameter at which the crack occurred. Then, the bending diameter where the crack occurred was the bending diameter, and the polarizer protective film single layer was used as a model, the same simulation as the above simulation was performed, and the strain in the direction orthogonal to the bending radius of the flexure was calculated, and it was taken as Elongation at break.

In addition, with regard to the elongation at break of the hard coat, ITO layer, and alternative ITO layer, the elongation at break of the window film, transparent resin substrate, and alternative transparent resin substrate laminated with the hard coating is used to calculate the protection of the polarizer. The elongation at break of the film is calculated using the same calculation method as the elongation at break of each.

The calculated elongation at break of the hard coat layer, polarizer protective film, ITO layer, and alternative ITO layer of each embodiment and each comparative example are listed in Tables 2-1 to 2-3.

[table 2-1]

[Table 2-2]

[Table 2-3]

[table 3]

[Table 4]

[table 5]

[Table 6]

(Evaluation) From Tables 2-1 to 2-3 and Figure 11, the following situations can be seen. That is, in the display devices of Comparative Examples 1 to 11 that do not satisfy 0.8<A/A'<1.2...(1), 0<B/B'<0.9...(2), the results are calculated by simulation The elongation of the ITO layer during bending deformation is greater than 1.50% of the elongation at break of the ITO layer, and/or the elongation of the hard coating layer during bending deformation is greater than 4.00% of the elongation at break of the hard coating layer. That is, it is shown that the ITO layer and/or the hard coat layer will be broken. In the display devices of Comparative Examples 1 to 3, 5, 7, and 10 actually produced, cracks also occurred in the ITO layer and/or the hard coat layer. In contrast, in the display devices of Examples 1 to 21 satisfying the above-mentioned formulas (1) and (2), the elongation of the ITO layer and the hard coat layer during bending deformation calculated by simulation is smaller than the fracture of the ITO layer. 1.50% of elongation and 4.00% of elongation at break of hard coating. That is, it is shown that the ITO layer and the hard coat layer will not be broken. In the actual display devices of Examples 3, 6, 9, and 12-15, no cracks were observed in the ITO layer and the hard coating layer. In this way, the simulation results of the embodiment and the comparative example are very consistent with the actual production of the embodiment and the comparative example with or without cracks. Therefore, it can be seen that, in the display device of each embodiment, the elongation rate of the ITO layer and the hard coating layer during bending deformation can be higher than that of the ITO layer and the hard coating layer by being configured to satisfy the above formulas (1) and (2). The fracture elongation of the layer is smaller, and the fracture of the ITO layer and the hard coating can be suppressed.

In addition, in the display devices of Examples 1-21, the elongation of the polarizer protective film calculated by simulation is also lower than the breaking elongation (4.00%), and in the actual examples 3, 6, 9, and 9 No cracks were observed in the protective film of the polarizer in the display devices of 12-15. In this way, the simulation results of the embodiment and the comparative example are very consistent with the actual production of the embodiment and the comparative example with or without cracks. Therefore, it can be seen that in the display device of each embodiment, by satisfying the above-mentioned formulas (1) and (2), the elongation of the polarizing member protective film during bending deformation can be made greater than that of the polarizing member protective film. The smaller the rate, the breakage of the protective film of the polarizer can be suppressed.

In addition, in the display devices of Examples 1-12, 16, 17, and 19-21, the elongation of the ITO layer and the hard coat layer calculated by the simulation is lower than the elongation at break, and the replacement ITO calculated by the simulation The elongation of the layer is also lower than the elongation at break (0.65%). In the display devices of Examples 3, 6, 9, and 12 actually produced, no cracks were observed in the replacement ITO layer. In this way, the simulation results of the embodiment and the comparative example are very consistent with the actual production of the embodiment and the comparative example with or without cracks. Therefore, it can be seen that in the display devices of Examples 1-12, 16, 17, 19-21, the elongation of the replacement ITO layer during bending deformation can also be made smaller than the elongation of the replacement ITO layer, and the replacement can be suppressed. Breaking of the ITO layer.

In addition, in the display devices of Examples 1-12, 16, 17, 19-21, the elongation of the replacement ITO layer is also lower than the elongation at break (0.65%), and the ITO layer, polarizer protective film, replacement All of the ITO layer and the hard coat layer of the thin film sealing layer are calculated by simulation to make the elongation during bending deformation lower than the elongation at break. In the actual examples 1-12, 16, 17, 19-21 In the display device, no cracks were observed in the ITO layer, the protective film of the polarizer, the ITO layer of the replacement film sealing layer, and the hard coating. In this way, the simulation results of the embodiment and the comparative example are very consistent with the actual production of the embodiment and the comparative example with or without cracks. Therefore, it can be seen that in the display devices of Examples 1-12, 16, 17, and 19-21, the display device can be bent by satisfying 0.8<A/A'<0.975 and 0.3<B/B'<0.9 The ITO layer, the polarizer protective film, the ITO layer that replaces the film sealing layer, and the hard coat during deformation have a smaller elongation than each layer and film, which can prevent the breakage of each layer and film.

Table 3 rearranges Comparative Example 1 and Examples 1 to 3, Comparative Example 2 and Examples 4 to 6, Comparative Example 11 and Examples 19 to 21 in Tables 2-1 to 2-3 for easy comparison. From Tables 2-1 to 2-3, Table 3, and Figure 7, the following can be seen.

The display devices of Examples 7-9 are display devices of the same composition except for the second adhesive layer. The shear elastic modulus G'of the second adhesive layer is the larger in the order, and the elongation of the ITO layer is The elongation rate of the ITO layer that replaces the thin film sealing layer is the smaller in the ranking.

In addition, the display devices of Examples 10 to 12 are of the same structure except for the second adhesive layer, and the third adhesive layer is not the adhesive layer 2 of Examples 1 to 4 but the display device of the adhesive layer 3. The second adhesive layer The shear elastic modulus G'is the larger in the ranking, and the elongation of the ITO layer and the elongation of the ITO layer replacing the film sealing layer are the smaller in the ranking.

In addition, the display devices of Comparative Example 1, Examples 1 to 3 have the same structure except for the second adhesive layer, and the third adhesive layer is not the adhesive layer 2 of Examples 7-9 or the adhesive of Examples 10-12. Layer 3 is the display device of the adhesive layer 4. The shear elastic modulus G'of the second adhesive layer is the larger in the order, and the elongation of the ITO layer and the elongation of the ITO layer that replaces the film sealing layer are in the order The middle is the smaller.

In addition, the display devices of Comparative Example 2 and Examples 4 to 6 are display devices as described below: Except for the second adhesive layer, the rest have the same structure, and the third adhesive layer is not the adhesive layer 2 of Examples 7 to 9 The adhesive layer 3 of Examples 10 to 12 is the adhesive layer 4, and the adhesive layer 4 is not the adhesive layer 1 of Examples 1 to 3, Examples 7 to 12, and Comparative Example 1 but the adhesive layer 2; the second adhesive layer The shear elastic modulus G'is the larger in the ranking, and the elongation of the ITO layer and the elongation of the ITO layer replacing the film sealing layer are the smaller in the ranking.

In addition, the display devices of Comparative Example 11 and Examples 19 to 21 are display devices as described below: Except for the second adhesive layer, the rest have the same structure, and the first adhesive layer, the third adhesive layer, and the fourth adhesive layer have the same The composition of Comparative Example 2 and Example 4 is the same, and the window film of the window member is not the window film 1 of Examples 1-12 and Comparative Examples 1-2 but the window film 2; the shear elastic modulus of the second adhesive layer G'is the larger in the ranking, and the elongation of the ITO layer and the elongation of the ITO layer replacing the thin-film sealing layer are the smaller in the ranking.

It can be seen from the above that by increasing the shear elastic modulus G'of the second adhesive layer, the elongation of the ITO layer during bending deformation and the elongation of the ITO layer that replaces the thin film sealing layer can be reduced, and ITO can be suppressed. The fracture of the ITO layer and the replacement film sealing layer.

Table 4 is a rearrangement of Examples 18, 9, 12, and 3 in Tables 2-1 to 2-3 for easy comparison. From Tables 2-1 to 2-3, Table 4, and Figure 8, the following can be seen.

The display devices of Examples 18, 9, 12, and 3 are display devices of the same composition except for the third adhesive layer. The shear elastic modulus G'of the third adhesive layer is the larger in the order, and the ITO layer The elongation is the larger in the ranking.

It can be seen from the above that by reducing the shear modulus G'of the third adhesive layer, the elongation of the ITO layer during bending deformation can be reduced, and the fracture of the ITO layer can be suppressed.

Table 5 rearranges Examples 12, 6, 13, and 14 in Tables 2-1 to 2-3 for easy comparison. From Tables 2-1 to 2-3, Table 5, and Figure 9, the following can be seen.

The display devices of Examples 12, 6, 13, and 14 are display devices of the same composition except for the fourth adhesive layer. The shear elastic modulus G'of the fourth adhesive layer is the larger in the order, and the ITO layer The elongation of the ITO layer and the elongation of the ITO layer that replaces the thin-film sealing layer are the larger in the order.

It can be seen from the above that by reducing the shear elastic modulus G'of the fourth adhesive layer, the elongation of the ITO layer during bending deformation and the elongation of the ITO layer that replaces the film sealing layer can be reduced, and the ITO layer can be suppressed And the fracture of the ITO layer that replaces the thin film sealing layer.

Table 6 rearranges Example 15 and Comparative Examples 3 to 5, Examples 12 and 16 and Comparative Example 6, Examples 3 and 17 and Comparative Example 7 in Table 1 for easy understanding. From Tables 2-1 to 2-3, Table 6, and Figure 10, the following can be seen.

The display devices of Example 15 and Comparative Examples 3 to 5 are display devices of the same structure except for the first adhesive layer. The shear elastic modulus G'of the first adhesive layer is the larger in the order, while the hard-coated The elongation of the layer is the larger in the order.

In addition, the display devices of Examples 12, 16 and Comparative Example 6 are display devices as described below: Except for the first adhesive layer, the rest have the same structure, and the third adhesive layer is not the one of Example 15 and Comparative Examples 3 to 5. The adhesive layer 3 is the adhesive layer 4, and the fourth adhesive layer is not the adhesive layer 4 of Example 15 and Comparative Examples 3 to 5 but the adhesive layer 1. The shear elastic modulus G′ of the first adhesive layer in Examples 12 and 16 is the same, but the thickness of the first adhesive layer in Example 16 is smaller than that of the first adhesive layer in Example 12. Therefore, compared with Example 12, the hardness of the first adhesive layer of Example 16 is greater. Also, as mentioned above, in terms of the factors determining the hardness of the adhesive layer, the shear elastic modulus G'of the adhesive layer is the main controlling factor, because the shear elastic modulus G'of Comparative Example 6 is higher than that of Example 16. The elastic modulus G'is more than 2 times larger, so compared to Example 16, the hardness of the first adhesive layer of Comparative Example 6 is greater. Therefore, the hardness of the first adhesive layer is the greater in the ranking, and the elongation of the hard coating is the greater in the ranking.

In addition, the display devices of Examples 3, 17 and Comparative Example 7 have the same structure except for the first adhesive layer, and the fourth adhesive layer is not the adhesive layer 3 of Examples 12, 16 and Comparative Example 6, but the adhesive layer 4 In the display device, the hardness of the first adhesive layer is the larger in the ranking, and the elongation of the hard coating is the larger in the ranking.

It can be seen from the above that by reducing the hardness of the first adhesive layer, the elongation of the hard coating layer during bending deformation can be reduced, and the fracture of the hard coating layer can be suppressed.

The arrows in the strain distribution diagrams of Figs. 7-10 show the corresponding layer or film when the hardness of the corresponding adhesive layer increases, and the strain shifts to the tensile direction or the compressive direction. In addition, the dotted line indicates the elongation at break of the corresponding layers and films.

It can be seen from Figures 7 to 10 that in the display devices of the various examples and comparative examples where multiple layers of layers and components are laminated through multiple layers of adhesive layers, when a certain adhesive layer is hardened, the display device is laminated on the layer when it is bent. The strain of the layer or member on the outer side of the adhesive layer will shift to the tensile direction, and the strain of the layer or member laminated on the inner side of the adhesive layer will shift to the compression direction.

For example, with regard to Comparative Example 1 and Examples 9 to 11, referring to FIG. 7, in the sequence, the shear elastic modulus G'of the second adhesive layer is larger, that is, the hardness of the second adhesive layer becomes larger, and As the hardness of the second adhesive layer increases, the strain of the layer or member outside the second adhesive layer shifts to the tensile direction, and the strain of the layer or member inside the second adhesive layer shifts to the compression direction. The same is true for the embodiment and/or comparative example groups in FIGS. 8 to 10.

Above, the present invention has been described with reference to the drawings for specific embodiments, but the present invention can be modified in addition to the structure described in the drawings. Therefore, the present invention is not limited by the constitution described in the drawings, and its scope should be interpreted as being limited by the scope of the attached patent application and its equivalent scope.

10: UV curable resin 12: UV curable resin 14: Substrate 20: manufacturing steps 21: Reel 22: Die head 24: Pressure roller 25: Ultraviolet radiation device 26: Peel roller 27: Ultraviolet radiation device 29: Die head 30: Roll version 31: Conveyor roller 32: Die head 34: Pressure roller 35: Ultraviolet radiation device 36: Peel roller 37: Ultraviolet radiation device 39: Die 40: Roller version 100: display device 101: Multilayer structure 103: Substrate laminate 110: Optical film components 111: Polarizing film 113: retardation film 115: Circularly polarized functional film laminate 117: Polarized parts 119: Polarizer protective film 120: The first adhesive layer 130: Window component 131: Hard coating 133: Window Film 140: second adhesive layer 150: Panel component 151: Film sealing layer 153: Panel base 160: third adhesive layer 170: Touch sensor component 171: Transparent conductive layer 173: Transparent film 180: 4th adhesive layer 190: Protective member 900: Organic EL display device 901: Organic EL display panel 912-1, 912-2: Transparent conductive layer 915-1, 915-2: Substrate film 916-1, 916-2: Transparent conductive film 917: divider 920: Optical laminate 921: Polarizing parts (polarizing film) 922-1,922-2: Protective film 923: retardation film (retardation layer, retardation film) 930: Touch panel

FIG. 1 is a cross-sectional view showing a conventional organic EL display device. Fig. 2 is a cross-sectional view showing a display device according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing a display device according to another embodiment of the present invention. Fig. 4 is a diagram showing a method of manufacturing a retardation film used in an embodiment. Fig. 5 is a diagram showing the simulation method of the embodiment of the present invention. Fig. 6 is a diagram illustrating the strain perpendicular to the direction of the bending radius. FIG. 7 is a graph showing the strain distribution in the stacking direction of the embodiment and the comparative example in which the shear elastic modulus G'of the second adhesive layer is changed. FIG. 8 is a graph showing the strain distribution in the stacking direction of the embodiment in which the shear elastic modulus G′ of the third adhesive layer is changed. FIG. 9 is a graph showing the strain distribution in the stacking direction of the embodiment in which the shear elastic modulus G'of the fourth adhesive layer is changed. FIG. 10 is a diagram showing the strain distribution in the stacking direction of the embodiment in which the shear elastic modulus G'of the first adhesive layer is changed. Figure 11 is a graph showing the relationship between A/A' and B/B'. Fig. 12 is a diagram showing a method of evaluating rupture.

Claims (10)

A display device which is bendable and has: an optical film member, a first adhesive layer, a window member, a second adhesive layer, and a laminated structure, wherein the window member is laminated on the optical film member through the first adhesive layer One side, and the laminated structure system is laminated on the other side of the optical film member through the second adhesive layer and includes a panel member; The display device is characterized by: The window member has a hard coating on the surface opposite to the first adhesive layer; The layered structure has a layer on the surface of the second adhesive layer side that is easier to break when bending and deforming than the window member and the optical film member; The following equations (1) and (2) are established between the following strain differences A, A', B, and B', thereby the elongation of the aforementioned easy-to-break layer and the aforementioned hard coating after bending deformation It is suppressed to a value smaller than the respective elongation at break: The display device is bent at an angle of 180° to the outside in the form of the window member, and the bend is deformed into a state of being bent at an angle of 180°. The distance between the parallel and opposite outermost surfaces of the display device becomes At 4mm, the strain in the direction orthogonal to the bending radius generated on the one surface of the optical film member, and the strain in the direction orthogonal to the bending radius generated on the surface of the window member facing the first adhesive layer The difference is set to A; In the same manner as after bending and deforming the outer side and the inner side of the display device, the optical film member and the window member are bent at an angle of 180° in the state of a single layer, and the bending is changed. When the distance between the opposing outermost surfaces of the optical film member and the window member in a state of being bent at an angle of 180° is 4mm, the direction of the bending radius generated on the outer surface of the optical film member The difference between the strain in the perpendicular direction and the strain in the direction perpendicular to the direction of the bending radius generated on the inner surface of the aforementioned window member is set to A'; The display device is bent at an angle of 180° to the outside in the form of the window member, and the bend is deformed into a state of being bent at an angle of 180°. The distance between the parallel and opposite outermost surfaces of the display device becomes At 4mm, the strain in the direction perpendicular to the bending radius generated on the other surface of the optical film member, and the strain in the direction perpendicular to the bending radius generated on the surface of the laminated structure facing the second adhesive layer Set the strain difference as B; In the same manner as after bending and deforming the outer side and the inner side of the display device, the optical film member and the laminated structure are bent at an angle of 180° in the state of a single layer, and the bending is performed. When the distance between the parallel and opposite outermost surfaces of the optical film member and the laminated structure in the state of being bent at an angle of 180° becomes 4mm, the bending and bending of the inner surface of the optical film member The difference between the strain in the direction perpendicular to the radial direction and the strain in the direction perpendicular to the bending radius generated on the outer surface of the aforementioned laminated structure is set to B'; 0.8＜A/A’＜1.2　　　　・・・・(1) 0＜B/B’＜0.9　　　　・・・・(2). The display device of claim 1, wherein the aforementioned optical film member is a circularly polarized film laminate in which a polarizing film is laminated with a retardation film. The display device of claim 2, wherein the aforementioned polarizing film is a laminate in which a polarizing member and a polarizing member protective film located on at least one side of the polarizing member are laminated. The display device of claim 3, wherein the polarizer protective film includes acrylic resin. The display device according to any one of claims 1 to 4, wherein the layer more easily broken than the window member and the optical film member is a film sealing layer formed on the surface of the panel member on the side of the second adhesive layer. A display device according to any one of claims 1 to 4, wherein the laminated structure system has a film sealing layer formed on the surface of the panel member on the side of the second adhesive layer, and the film sealing layer is opposite to the panel member The touch sensor member is laminated on the side surface through the third adhesive layer, and a transparent conductive layer is formed on the surface of the touch sensor member opposite to the panel member, and the transparent conductive layer is compared with The window member and the optical film member are more easily broken in the form of a layer laminated on the second adhesive layer. The display device according to any one of claims 1 to 6, wherein the shear elastic modulus of the second adhesive layer is greater than the shear elastic modulus of the first adhesive layer. The display device according to any one of claims 1 to 7, wherein a fourth adhesive layer is further provided on the surface of the panel member opposite to the second adhesive layer, and a protective member is laminated through the fourth adhesive layer. The display device of claim 8, wherein the shear elastic modulus of the fourth adhesive layer is smaller than the shear elastic modulus of the second adhesive layer and smaller than the shear elastic modulus of the third adhesive layer. A substrate laminate is used for the display device of any one of claims 6 to 9 and has: The aforementioned optical film member; The window member is laminated on one surface of the optical film member through the first adhesive layer; and The touch sensor component is laminated on the other side of the optical film component through the second adhesive layer and includes the transparent conductive layer.

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