Protective member and organic electroluminescence display device

Abstract

To provide an organic electroluminescence display device which is capable of suppressing damage to the other side portion in the thickness direction of an organic electroluminescence panel member which is a display surface of a display panel, and provide a protective member to be used therefor.SOLUTION: An organic EL display device 1 includes an organic EL panel member 4, a first adhesive layer 16, a base material 17, a second adhesive layer 18, and a metal plate 6 in this order. When a tensile elastic modulus E of the base material 17 is 1 GPa or more and less than 5 GPa (1), the tensile elastic modulus E of the first adhesive layer 16 is 0.03 MPa or more and less than 0.15 MPa. When the tensile elastic modulus E of the base material 17 is 5 GPa or more and less than 10 GPa (2), the tensile elastic modulus E of the first adhesive layer 16 is 0.03 MPa or more and less than 0.15 MPa, or the tensile elastic modulus E of the second adhesive layer 18 is 0.03 MPa or more and less than 0.15 MPa. When the tensile elastic modulus E of the base material 17 is 10 GPa or more and 15 GPa or less (3), the tensile elastic modulus E of the second adhesive layer 18 at 25°C is 0.03 MPa or more and 0.15 MPa or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a protective member and an organic electroluminescence display device. [Background technology]

[0002] Conventionally, an organic electroluminescence display device has been known that includes a metal sheet and a display panel in that order toward the user's viewing side (see, for example, Patent Document 1 below). In the organic electroluminescence display device of Patent Document 1, the display panel is reinforced by the metal sheet.

[0003] Also known is a mobile terminal in which a bendable portion of a flexible display supported by a first housing and a second housing is allowed (see, for example, Patent Document 2 below). In the mobile terminal of Patent Document 2, the bendable portion bulges when the flexible display is folded. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-21091 [Patent Document 2] WO2018 / 198307 issue Summary of the Invention [Problem to be solved by the invention]

[0005] From the viewpoint of miniaturization, it has been considered to fold the organic electroluminescence display device so that the display surfaces (visible sides) of the display panels are closer to each other in the configuration of Patent Document 1. However, when the organic electroluminescence display device is folded into a U-shape in cross section, it is difficult to bring the display surfaces of the two flat portions away from the bent portion close enough to each other.

[0006] On the other hand, as a variation of Patent Document 2, a method has been proposed in which the organic electroluminescence display device has the configuration of Patent Document 1 and is folded so that the folded portions bulge on both sides of the two flat portions in the thickness direction in a cross-sectional view (tentative method). With this tentative method, the display surfaces of the two flat portions can be brought sufficiently close to each other.

[0007] In the configuration of Patent Document 1, because the metal sheet is not elastic, when the metal sheet is folded with the metal sheet facing outward, compressive stress is applied to the other components on the inside, causing misalignment. However, in the folding method disclosed in Patent Document 2, there is a change point at the boundary adjacent to the flat portion of the folded section where the bending direction changes, so the above-mentioned misalignment is stopped at this change point, and stress is concentrated near the change point. Because the metal sheet is not elastic, the distortion of the other components on the inside of the metal sheet becomes greater the closer they are to the metal sheet. This causes the display surface of the display panel to be easily damaged.

[0008] The present invention provides an organic electroluminescence display device capable of suppressing damage to the other side in the thickness direction of an organic electroluminescence panel member that is the display surface of a display panel, and a protective member used therein. [Means for solving the problem]

[0009] The present invention [1] is directed to an organic electroluminescence panel member including, in order toward one side in a thickness direction, an organic electroluminescence panel member, a first adhesive layer, a substrate, a second adhesive layer, and a metal plate, wherein the substrate has a tensile modulus E at 25°C of 1 GPa or more and 15 GPa or less, and the substrate has a tensile modulus E at 25°C of 1 GPa or more and less than 5 GPa (1). In this case, the first adhesive layer has a tensile modulus E at 25°C of 0.03 MPa or more and less than 0.15 MPa, and the substrate has a tensile modulus E at 25°C of 1 GPa or more and less than 5 GPa (2). When the tensile modulus E is 5 GPa or more and less than 10 GPa (2), the tensile modulus E of the first adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, or the tensile modulus E of the second adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, and when the tensile modulus E of the base material at 25°C is 10 GPa or more and 15 GPa or less (3), the tensile modulus E of the second adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa. below The present invention includes an organic electroluminescent display device,

[0010] The present invention [2] further comprises a window member and an optical member, wherein the window member, the optical member, the organic electroluminescence panel member, the first adhesive layer, the base material, the second adhesive layer, and the metal plate are arranged in this order toward one side in the thickness direction, and extend in one direction perpendicular to the thickness direction, and have one side portion, another side portion spaced apart from the one side portion, and an intermediate portion located therebetween in the extending direction, and the one side portion and the other side portion on one surface in the thickness direction of the metal plate are respectively connected to a surface of a first support plate, and the one side portion and the The organic electroluminescent display device according to [1] is fixed to the surface of a first support plate and a second support plate spaced 16 mm apart in the extension direction, and the first support plate and the second support plate are moved in a parallel relationship facing each other, so that the distance between one surface in the thickness direction of the one side of the metal plate and one surface in the thickness direction of the other side of the metal plate is 2 mm, and so that the maximum distance between the surfaces in the thickness direction that face each other at the center of the metal plate in the thickness direction exceeds 2 mm.

[0011] The present invention [3] is a protective member used in the organic electroluminescence display device according to [1], which comprises a first adhesive layer, a substrate, and a second adhesive layer in this order toward one side in a thickness direction, and in the case where the tensile modulus E of the substrate at 25°C is 1 GPa or more and 15 GPa or less, and the tensile modulus E of the substrate at 25°C is 1 GPa or more and less than 5 GPa (1), the tensile modulus E of the first adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, and When the tensile modulus E at 25°C is 5 GPa or more and less than 10 GPa (2), the tensile modulus E at 25°C of the first adhesive layer is 0.03 MPa or more and less than 0.15 MPa, or the tensile modulus E at 25°C of the second adhesive layer is 0.03 MPa or more and less than 0.15 MPa, and when the tensile modulus E at 25°C of the base material is 10 GPa or more and 15 GPa or less (3), the tensile modulus E at 25°C of the second adhesive layer is 0.03 MPa or more and less than 0.15 MPa. below The protective member includes: [Effects of the Invention]

[0012] The protective member of the present invention and the organic electroluminescence panel member display device including the same can suppress damage to the other side portion in the thickness direction of the organic electroluminescence panel member. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view of an embodiment of an organic EL display device of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a protective member with a release sheet used in the organic EL display device shown in FIG. [Figure 3] 3A and 3B illustrate the use of the organic EL display device shown in FIG. 1 and a bending simulation and bending test. Fig. 3A shows the organic EL display device before and after bending. Fig. 3B shows the organic EL display device after and after bending. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Organic electroluminescence display device] An embodiment of the organic electroluminescence display device of the present invention, its manufacturing method and use will be described with reference to Figures 1 to 3B. In addition, in the enlarged view of the circled area in Figure 3B, the positions and shapes of the organic EL panel member 4, the protective member 5 and the metal plate 6 (described later) are clearly shown. Show To avoid this, the window member 2 and the optical member 3 (described later) are omitted.

[0015] Hereinafter, the organic electroluminescence display device will be simply referred to as an "organic EL display device." In Fig. 1, the upper side of the paper of the organic EL display device 1 is the user's viewing side, that is, the front side. In Fig. 1, the lower side of the paper of the organic EL display device 1 is the opposite side of the user's viewing side, that is, the back side.

[0016] As shown in FIG. 1, the organic EL display device 1 extends in a plane direction perpendicular to the front-to-back direction. The organic EL display device 1 has, for example, a flat plate shape. The organic EL display device 1 has a flat front surface 21 and a flat back surface 22. The front surface 21 is visible to a user. The organic EL display device 1 is bendable around an intermediate portion 24 located between two opposing sides 23 spaced apart in the plane direction. When the organic EL display device 1 is bent, the front surfaces 21 approach each other and face each other, making them invisible to a user. Note that, as shown in FIG. 3B, when the organic EL display device 1 is bent, the intermediate portion 24 extends along a first direction to form a ridge or crease. The first direction is a direction along the sides 23. The first direction corresponds to the paper thickness direction in FIGS. 1, 3A, and 3B. When the organic EL display device 1 is bent, the back surface 22 becomes visible to a user. 1 and 3A, before being folded and in the unfolded state, the organic EL display device 1 has a middle portion 24, one side portion 26 located on one side of the middle portion 24 in the second direction, and another side portion 27 located on the other side of the middle portion 24 in the second direction. The second direction is perpendicular to the first direction and the front-to-back direction. The second direction is the left-to-right direction in FIGS. 1 and 3A.

[0017] The organic EL display device 1 includes, in order from the front side to the back side, a window member 2, an optical member 3, an organic EL panel member 4 (organic electroluminescence panel member 4), a protective member 5, and a metal plate 6.

[0018] [Window member 2] The window member 2 forms a surface 21 of the organic EL display device 1. The window member 2 extends in the planar direction. The window member 2 includes a hard coat layer 7, a window film 8, and a window adhesive layer 9, which are arranged in this order toward the back side.

[0019] [Hard coat layer 7] The hard coat layer 7 is a protective member that suppresses damage caused by friction on the surface 21 of the organic EL display device 1. The hard coat layer 7 is made of, for example, a cured product of a curable composition or a molded product of a thermoplastic composition. The thickness of the hard coat layer 7 is, for example, 5 μm or more, preferably 7 μm or more, and, for example, 30 μm or less. The hard coat layer 7 is described, for example, in JP 2020-064236 A.

[0020] [Window Film 8] The window film 8 is disposed on the back surface of the hard coat layer 7. Specifically, the window film 8 is in contact with the back surface of the hard coat layer 7. Examples of materials for the window film 8 include resin and glass. Examples of resin include polyimide resin, acrylic resin, and polycarbonate resin. The thickness of the window film 8 is, for example, 1 μm or more and, for example, 100 μm or less. A commercially available product can be used as the window film 8. Examples of commercially available products include the C Series (manufactured by KOLON) and G-LEAF (manufactured by Nippon Electric Glass Co., Ltd.). The window film 8 is described, for example, in JP 2020-149065 A and JP 2020-064236 A.

[0021] [Window adhesive layer 9] The window adhesive layer 9 is an adhesive layer that adheres (pressure-sensitively bonds) the window film 8 to the optical member 3. The window adhesive layer 9 is disposed on the back surface of the window film 8. Specifically, the window adhesive layer 9 is in contact with the back surface of the window film 8. Examples of materials for the window adhesive layer 9 include known adhesives, and specifically, the material is appropriately selected from the materials for the first adhesive layer 16 described below. The thickness of the window adhesive layer 9 is, for example, 1 μm or more, preferably 5 μm or more, and more preferably 10 μm or more, and for example, 200 μm or less, preferably 150 μm or less, and more preferably 100 μm or less.

[0022] [Physical properties of window material 2] The total light transmittance of the window member 2 is, for example, 80% or more, preferably 85% or more, and for example, 95% or less. The total light transmittance of the window member 2 is measured based on JIS K 7375-2008. The total light transmittances of the other subsequent members are measured in the same manner as above.

[0023] [Optical component 3] The optical member 3 extends in the planar direction. The optical member 3 is disposed on the back surface of the window member 2. Specifically, the optical member 3 is in contact with the back surface of the window member 2. The optical member 3 includes, in order toward the back side, a polarizer protective film 10, a polarizer 11, an optical compensation layer 12, and an optical adhesive layer 13.

[0024] [Polarizer protective film 10] The polarizer protective film 10 is disposed on the back surface of the window adhesive layer 9. Specifically, the polarizer protective film 10 is in contact with the back surface of the window adhesive layer 9. The polarizer protective film 10 protects the polarizer 11, which will be described below, from the front side. The polarizer protective film 10 is isotropic. Examples of materials for the polarizer protective film 10 include acrylic resins. The thickness of the polarizer protective film 10 is, for example, 10 μm or more and, for example, 60 μm or less, preferably 55 μm or less, and more preferably 50 μm or less. The polarizer protective film 10 is described in JP 2019-218513 A.

[0025] [Polarizer 11] The polarizer 11 is disposed on the back surface of the polarizer protective film 10. Specifically, the polarizer 11 is in contact with the back surface of the polarizer protective film 10. Examples of the polarizer 11 include a hydrophilic film that has been dyed and stretched, a hydrophilic film that has been dehydrated, and a polyvinyl chloride film that has been dehydrochlorinated. Examples of the hydrophilic film include a PVA film. The polarizer 11 has a thickness of, for example, 1 μm or more, preferably 3 μm or more, and for example, 15 μm or less, preferably 10 μm or less. The polarizer 11 is described in JP 2020-149065 A and JP 2019-218513 A.

[0026] [Optical compensation layer 12] The optical compensation layer 12 is in contact with one surface of the polarizer 11 in the thickness direction. The optical compensation layer 12 is, for example, a retardation film, specifically, functions as a λ / 4 plate. As a result, a polarizing film 25 composed of the polarizer 11 and the optical compensation layer 12 has circular polarization properties. Examples of materials for the optical compensation layer 12 include materials having the above optical properties, such as polycarbonate resin. The optical compensation layer 12 may also be a laminate, and although not shown, for example, includes a first liquid crystal alignment layer and a second liquid crystal alignment layer, arranged in this order toward the back side. The first liquid crystal alignment solidified layer functions, for example, as a λ / 2 plate. The second liquid crystal alignment solidified layer functions, for example, as a λ / 4 plate. The thickness of the optical compensation layer 12 is, for example, 0.1 μm or more, for example, 50 μm or less, preferably 40 μm or less. The optical compensation layer 12 is described in JP 2019-218513 A. The optical compensation layer 12 is fixed (attached) to the optical pressure-sensitive adhesive layer 13 via, for example, an adhesive (not shown). The adhesive is described in, for example, JP-A-2019-218513.

[0027] [Optical adhesive layer 13] The optical adhesive layer 13 extends in the planar direction. The optical adhesive layer 13 is disposed on the back surface of the optical compensation layer 12. The optical adhesive layer 13 is in contact with the back surface of the optical compensation layer 12. The material, thickness, physical properties, etc. of the optical adhesive layer 13 are the same as those of the window adhesive layer 9 described above.

[0028] [Physical properties of optical member 3] The optical member 3 has a total light transmittance of, for example, 30% or more, preferably 35% or more, more preferably 40% or more, and for example, 50% or less.

[0029] [OLED panel component 4] The organic EL panel member 4 extends in the planar direction. The organic EL panel member 4 includes a panel body 14 and a thin-film sealing layer 15. The panel body 14 extends in the planar direction. Although not shown, the panel body 14 includes, in this order toward the front side, a substrate, two electrodes, and an organic EL layer sandwiched between the two electrodes. The material of the substrate is the same as the material of the base material 17 described below.

[0030] [Thin film sealing layer 15] The thin film encapsulating layer 15 is called TFE (Thin Film Encapsulation). The thin film encapsulating layer 15 is disposed on the surface of the panel body 14. The thin film encapsulating layer 15 is disposed on the back surface of the optical adhesive layer 13. Specifically, the thin film encapsulating layer 15 is in contact with the back surface of the optical adhesive layer 13. The thin film encapsulating layer 15 has high hardness but low toughness. In other words, the thin film encapsulating layer 15 is brittle. The thin film encapsulating layer 15 is made of a material that satisfies the above-mentioned physical properties. Examples of materials for the thin film encapsulating layer 15 include inorganic compounds and resins. Examples of inorganic compounds include silicon nitride, silicon oxynitride, carbon nitride, and aluminum oxide.

[0031] [Thickness of OLED panel component 4] The thickness of the organic EL panel member 4 is, for example, 40 μm or less, preferably 30 μm or less, more preferably 20 μm or less, and is, for example, 10 μm or more.

[0032] [Protective material 5] The protective member 5 extends in the planar direction. The protective member 5 is disposed on the rear surface of the organic EL panel member 4. Specifically, the protective member 5 is in contact with the rear surface of the organic EL panel member 4. The protective member 5 protects the organic EL panel member 4 from the rear or back side. Therefore, the protective member 5 can be referred to as a "rear-side protective member" or a "back-side protective member." The protective member 5 includes, in order toward the rear side, a first adhesive layer 16, a substrate 17, and a second adhesive layer 18. Preferably, the protective member 5 includes only the first adhesive layer 16, the substrate 17, and the second adhesive layer 18.

[0033] [First adhesive layer 16] The first adhesive layer 16 is disposed on the back surface of the panel main body 14. Specifically, the first adhesive layer 16 is in contact with the back surface of the panel main body 14. The first adhesive layer 16 also forms the surface of the protection member 5.

[0034] [Material of first adhesive layer 16] The material of the first adhesive layer 16 is not limited as long as the tensile modulus E, which will be described later, is within a desired range. Examples of materials for the first adhesive layer 16 include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, fluorine adhesives, epoxy adhesives, and polyether adhesives. A preferred material for the first adhesive layer 16 is an acrylic adhesive.

[0035] [Acrylic adhesive] Examples of acrylic adhesives include crosslinked acrylic base polymers. The acrylic base polymers are obtained by polymerizing monomer components. The monomer components include, for example, a (meth)acrylate having an alkyl moiety with 1 to 24 carbon atoms as a main component. (Meth)acrylate means methacrylate and / or acrylate. The definition and usage of (meth)acrylate mentioned above are the same hereinafter. The alkyl moiety may be linear or branched. Examples of (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, and isooctyl Examples of suitable (meth)acrylates include (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate (i.e., lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, icosyl (meth)acrylate, docosyl (meth)acrylate, and tetracosyl (meth)acrylate. From the viewpoint of preparing a relatively soft PSA composition, preferred examples include (meth)acrylates having an alkyl moiety having 6 to 24 carbon atoms. The proportion of (meth)acrylate in the monomer components is, for example, 80% by mass or more, preferably 90% by mass or more, and, for example, 100% by mass or less, preferably 99.5% by mass or less.

[0036] The monomer component further contains a functional group-containing (meth)acrylate as an optional component. Examples of functional group-containing (meth)acrylates include hydroxyl group-containing (meth)acrylates and amide group-containing (meth)acrylates. Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of amide group-containing (meth)acrylates include (meth)acrylamide and dimethyl (meth)acrylamide. The amide group-containing (meth)acrylate may include an intramolecularly amide group-containing (meth)acrylate. Examples of intramolecularly amide group-containing (meth)acrylates include N-vinyl-2-pyrrolidone. The proportion of the functional group-containing (meth)acrylate in the monomer component is, for example, 1% by mass or more, preferably 5% by mass or more, and for example, 25% by mass or less, preferably 20% by mass or less.

[0037] The monomer components can be polymerized, for example, in the presence of a chain transfer agent. Examples of the chain transfer agent include thiol compounds. Examples of the thiol compounds include α-thioglycerol. The number of parts by mass of the chain transfer agent is, for example, 1 part by mass or more and, for example, 10 parts by mass or less, per 100 parts by mass of the monomer components.

[0038] The crosslinked product is obtained by blending a crosslinking agent with an acrylic base polymer and reacting the resulting crosslinking agent. Examples of crosslinking agents include isocyanate crosslinking agents, silane coupling agents, peroxides, and (meth)acrylates having multiple (meth)acryloyl groups. Examples of isocyanate crosslinking agents include trimethylolpropane-modified xylylene diisocyanate and trimethylolpropane-modified tolylene diisocyanate. Examples of silane coupling agents include epoxy group-containing silane coupling agents. Examples of epoxy group-containing silane coupling agents include 3-glycidoxypropyltrimethoxysilane. Examples of peroxides include organic peroxides. Examples of organic peroxides include benzoyl peroxide. Examples of (meth)acrylates having multiple (meth)acryloyl groups include hexanediol (meth)acrylate. These can be used alone or in combination. The number of parts by mass of the crosslinking agent is, for example, 0.1 parts by mass or more and, for example, 2 parts by mass or less, relative to 100 parts by mass of the acrylic base polymer.

[0039] Along with the blending of the crosslinking agent, additives can be added to the acrylic base polymer. Examples of additives include oligomers. Examples of oligomers include (meth)acrylic oligomers. The weight-average molecular weight of the (meth)acrylic oligomer is, for example, 1,000 or more, preferably 2,000 or more, and for example, 30,000 or less, preferably 10,000 or less. The weight-average molecular weight of the (meth)acrylic oligomer is determined by gel permeation chromatography in terms of standard polystyrene. The (meth)acrylic oligomer is obtained by polymerizing monomer components. The monomer components include the above-mentioned (meth)acrylate having an alkyl moiety with 1 to 24 carbon atoms and an alicyclic (meth)acrylate having an alicyclic alkyl (cycloaliphatic alkyl) moiety with 1 to 24 carbon atoms. Examples of the alicyclic alkyl moiety include monocyclic and polycyclic. Examples of monocyclic alicyclic (meth)acrylates include cycloalkyl (meth)acrylates such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate. Examples of polycyclic alicyclic (meth)acrylates include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and tricyclopentanyl (meth)acrylate. The proportion of (meth)acrylate in the monomer components is, for example, 10% by mass or more, preferably 20% by mass or more, and, for example, 70% by mass or less, preferably 45% by mass or less. The proportion of alicyclic (meth)acrylate in the monomer components is, for example, 30% by mass or more, preferably 55% by mass or more, and, for example, 90% by mass or less, preferably 80% by mass or less.

[0040] The glass transition temperature of the oligomer is, for example, 20° C. or higher, preferably 50° C. or higher, more preferably 80° C. or higher, and for example, 150° C. or lower. The glass transition temperature of the oligomer is calculated by the Fox equation.

[0041] The number of parts by mass of the oligomer added is, for example, 0.01 part by mass or more and, for example, 1 part by mass or less, relative to 100 parts by mass of the acrylic base polymer.

[0042] The total light transmittance of the first adhesive layer 16 is, for example, 60% or more, preferably 80% or more, more preferably 85% or more, and for example, 100% or less, preferably 95% or less.

[0043] There are no limitations on the thickness of the first adhesive layer 16. The thickness of the first adhesive layer 16 is, for example, 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and for example, 50 μm or less, preferably 40 μm or less, more preferably 25 μm or less.

[0044] [Base material 17] The base material 17 is disposed on the back surface of the first adhesive layer 16. Specifically, the base material 17 is in contact with the back surface of the first adhesive layer 16. Therefore, the base material 17 is fixed to the panel body 14 via the first adhesive layer 16. The base material 17 is an intermediate layer in the protective member 5.

[0045] The material of the substrate 17 is not limited as long as the tensile modulus E of the substrate 17 is within a desired range, as described below. Examples of materials for the substrate 17 include resins. Examples of resins include olefin resins, polyester resins, acrylic resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, and polystyrene resins. Examples of olefin resins include polyethylene, polypropylene, and cycloolefin polymers. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of acrylic resins include polymethacrylate. Examples of resins include preferably polyester resins and polyimide resins.

[0046] A commercially available product can be used for the substrate 17. Examples of commercially available products include the Lumirror series (PET substrate, manufactured by Toray Industries, Inc.), the C series (polyimide resin substrate, manufactured by KOLON Corporation), and the UPILEX series (polyimide resin substrate, manufactured by Ube Industries, Ltd.).

[0047] There are no limitations on the thickness of the substrate 17. The thickness of the substrate 17 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, more preferably 30 μm or more, and for example, 250 μm or less, preferably 150 μm or less, more preferably 100 μm or less.

[0048] [Second adhesive layer 18] The second adhesive layer 18 is disposed on the back surface of the base material 17. Specifically, the second adhesive layer 18 is in contact with the back surface of the base material 17. The second adhesive layer 18 also forms the back surface of the protective member 5. Examples of materials for the second adhesive layer 18 include known adhesives, and specifically, the material is appropriately selected from the materials exemplified for the first adhesive layer 16 described below. The thickness of the second adhesive layer 18 is not limited. The thickness of the second adhesive layer 18 is, for example, 1 μm or more, preferably 10 μm or more, and more preferably 30 μm or more, and for example, 100 μm or less, preferably 80 μm or less, and more preferably 60 μm or less.

[0049] [Metal plate 6] The metal plate 6 is disposed on the back surface of the second adhesive layer 18. Specifically, the metal plate 6 is in contact with the back surface of the second adhesive layer 18. The metal plate 6 forms the back surface 22 of the organic EL display device 1. The metal plate 6 fixes the substrate 17 via the second adhesive layer 18.

[0050] Examples of materials for the metal plate 6 include metals. Examples of metals include aluminum, titanium, steel, 42 alloy, stainless steel, and magnesium alloys. A preferred example of the material for the metal plate 6 is stainless steel.

[0051] There are no limitations on the thickness of the metal plate 6. The thickness of the metal plate 6 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

[0052] The metal plate 6 has a tensile modulus E at 25° C. of, for example, 50 GPa or more, or preferably 100 GPa or more, and for example, 500 GPa or less, or preferably 250 GPa or less.

[0053] [Manufacture of organic EL display device 1] As shown in FIGS. 1 and 3A, an organic EL display device 1 is obtained by laminating a window member 2, an optical member 3, an organic EL panel member 4, a protective member 5, and a metal plate 6.

[0054] As shown in FIG. 2 , the protective member 5 can be prepared by protecting the first adhesive layer 16 and the second adhesive layer 18 with two release sheets 19A and 19B, respectively. Specifically, a protective member 20 with release sheets is prepared, which includes the protective member 5 and two release sheets 19A and 19B. In the protective member 20 with release sheets, one release sheet 19A, the first adhesive layer 16, the substrate 17, the second adhesive layer 18, and another release sheet 19B are arranged in this order in the thickness direction. Before contacting the first adhesive layer 16 with the panel main body 14, the one release sheet 19A is peeled from the first adhesive layer 16. Before contacting the second adhesive layer 18 with the metal plate 6, the other release sheet 19B is peeled from the second adhesive layer 18. The protective member 20 with release sheets and the protective member 5 included therein are both components for fabricating the organic EL display device 1. The protective member 5 is not yet in contact with either the panel body 14 or the metal plate 6. The protective member 20 with a release sheet and the protective member 5 are devices that can be distributed independently and are industrially applicable.

[0055] [Use of organic EL display device 1] As shown in FIG. 3A, when a user views the surface 21 of the organic EL display device 1, the organic EL display device 1 is opened so that the surface 21 is flat.

[0056] On the other hand, when the user does not view the surface 21 of the organic EL display device 1 and wants to store the organic EL display device 1 to make it smaller, the user folds the organic EL display device 1 as shown in FIG. 3B . At this time, the organic EL display device 1 is folded so that the middle portion 24 bulges out on both sides of the overlapping portion of the one side portion 26 and the other side portion 27 relative to the overlapping portion of the one side portion 26 and the other side portion 27. More specifically, the one side portion 26 is rotated 180 degrees around the center 29 of the middle portion 24, and the one side portion 26 is moved relative to the other side portion 27 so that the one side portion 26 and the other side portion 27 overlap. The one side portion 26 and the other side portion 27 face each other and are, for example, substantially parallel to each other.

[0057] The bent intermediate portion 24 (excluding the adjacent portion 31 described below) includes a central portion 29 and a neighboring portion 30 adjacent thereto. The central portion 29 and the neighboring portion 30 are curved so as to bulge toward the rear side. The protective member 5 between the neighboring portion 30 and the central portion 29 is subjected to a stress F that tends to cause displacement to one side and the other side in the second direction relative to the metal plate 6. This stress F can be referred to as a stress based on lateral displacement (displacement in the second direction).

[0058] The intermediate portion 24 also includes adjacent portions 31 adjacent to the one side portion 26 and the other side portion 27, respectively. However, the adjacent portions 31 are curved so as to bulge outward. The adjacent portions 31 include boundary portions 28 between the one side portion 26 and the other side portion 27 and the intermediate portion 24. The direction of curvature in the adjacent portions 31 is opposite to the direction of curvature in the central portion 29 and the neighboring portions 30. On the other hand, the one side portion 26 and the other side portion 27 do not have the above-mentioned curvature. Therefore, the stress F acting on the intermediate portion 24 accumulates (concentrates) in the adjacent portions 31. In particular, the stress F accumulates (concentrates) significantly in the boundary portions 28. As a result, the relatively fragile thin-film sealing layer 15 in the adjacent portions 31, including the boundary portions 28, is easily damaged.

[0059] However, in this embodiment, the modulus of elasticity of each layer in the protective member 5, which will be described next, is within a desired range, so that the above-mentioned damage to the thin film sealing layer 15 can be suppressed.

[0060] The stress F applied to the boundary portion 28 is determined as a strain (maximum strain) by a bending simulation, as described in the examples below.

[0061] [Elastic modulus of each layer in protective member 5] Next, the elastic modulus of the first adhesive layer 16, the base material 17, and the second adhesive layer 18 in the protective member 5 will be described.

[0062] [Tensile modulus E of substrate 17] The tensile modulus E of the substrate 17 at 25°C is 1 GPa or more and 15 GPa or less. If the tensile modulus E of the substrate 17 is less than 1 GPa, the protective member 5 cannot sufficiently support (reinforce) the organic EL panel member 4. On the other hand, if the tensile modulus E of the substrate 17 exceeds 15 GPa, the toughness of the substrate 17 becomes too poor, and the resistance of the organic EL display device 1 to bending decreases. The tensile modulus E of the substrate 17 is measured using a tensile tester. Details will be described in the examples below.

[0063] [Tensile modulus E of first adhesive layer 16 and second adhesive layer 18] Next, the tensile modulus E of the first adhesive layer 16 and the second adhesive layer 18 will be explained in order, dividing them into cases where the tensile modulus E of the substrate 17 at 25°C is 1 GPa or more and less than 5 GPa (1), where the tensile modulus E of the substrate 17 at 25°C is 5 GPa or more and less than 10 GPa (2), and where the tensile modulus E of the substrate 17 at 25°C is 10 GPa or more and 15 GPa or less (3).

[0064] [Case (1)] In case (1), the tensile modulus E of the first adhesive layer 16 at 25°C is 0.03 MPa or more and less than 0.15 MPa. The tensile modulus E of the first adhesive layer 16 is measured using a tensile tester. Details will be described in the Examples below. The tensile storage modulus E' of the first adhesive layer 16 can also be determined by measuring the shear storage modulus G' and Poisson's ratio ν of the first adhesive layer 16 and substituting them into the following equation. It is also known that the tensile storage modulus E' generally differs little from the tensile modulus E in a room temperature environment. Based on this knowledge, the tensile storage modulus E' of the first adhesive layer 16 can be determined by measuring the shear storage modulus G' of the first adhesive layer 16, without actually measuring the tensile modulus E of the first adhesive layer 16, and thus the tensile modulus E of the first adhesive layer 16 can be determined.

[0065] E'=2G'(1+ν) E': Tensile storage modulus G': Shear storage modulus ν: Poisson's ratio

[0066] In the measurement of the shear storage modulus G', the heating rate is 5°C / min and the frequency is 1 Hz.

[0067] In this case (1), the tensile modulus E of the substrate 17 is 1 GPa or more, 5 The base material 17 has a low tensile modulus of elasticity of less than GPa, making it relatively soft. This makes the base material 17 prone to lateral displacement, which can easily cause stress to be applied to the organic EL panel member 4. However, in this embodiment, the tensile modulus E of the first adhesive layer 16 is low, at 0.03 MPa or more and less than 0.15 MPa. This allows the first adhesive layer 16, which comes into contact with the organic EL panel member 4, to relieve the above-mentioned stress. As a result, damage to the organic EL panel member 4 can be suppressed.

[0068] On the other hand, if the tensile modulus E of the first adhesive layer 16 is 0.15 MPa or more, the first adhesive layer 16 cannot sufficiently relieve the above-mentioned stress, and therefore the first adhesive layer 16 cannot sufficiently suppress damage to the organic EL panel member 4. On the other hand, if the tensile modulus E of the first adhesive layer 16 is less than 0.03 MPa, the first adhesive layer 16 becomes excessively soft, and the first adhesive layer 16 cannot sufficiently relieve the above-mentioned stress, and therefore the first adhesive layer 16 cannot sufficiently suppress damage to the organic EL panel member 4.

[0069] The tensile modulus E of the first adhesive layer 16 is preferably 0.06 MPa or more, and preferably 0.12 MPa or less.

[0070] In case (1), the tensile modulus E of the second adhesive layer 18 is not limited. The tensile modulus E of the second adhesive layer 18 is, for example, 0.03 MPa or more, preferably 0.15 MPa or more, and for example, 0.45 MPa or less, preferably 0.30 MPa or less. The tensile modulus E of the second adhesive layer 18 is determined by the same method as the tensile modulus E of the first adhesive layer 16.

[0071] [Case (2)] In case (2), the tensile modulus E of the first adhesive layer 16 at 25°C is 0.03 MPa or more and less than 0.15 MPa, or the tensile modulus E of the second adhesive layer 18 at 25°C is 0.03 MPa or more and less than 0.15 MPa. In this case (2), the base material 17 is moderately soft. That is, the base material 17 has medium softness. Therefore, the first adhesive layer 16 having a relatively low tensile modulus E or the second adhesive layer 18 having a relatively low tensile modulus E can suppress damage to the thin-film encapsulating layer 15 in the adjacent portion 31 including the boundary portion 28 when the organic EL display device 1 is bent. Below, the case (2-1) in which the tensile modulus E of the first adhesive layer 16 is 0.03 MPa or more and less than 0.15 MPa and the case (2-2) in which the tensile modulus E of the second adhesive layer 18 is 0.03 MPa or more and less than 0.15 MPa will be described in detail.

[0072] <Case (2-1)> In the case (2-1), the first adhesive layer 16 has a tensile modulus E of 0.03 MPa or more and less than 0.15 MPa. Therefore, the first adhesive layer 16 is relatively soft. Therefore, the stress applied to the organic EL panel member 4 with which the first adhesive layer 16 comes into contact can be alleviated. As a result, damage to the thin-film sealing layer 15 in the organic EL panel member 4 can be suppressed. Note that if the tensile modulus E of the first adhesive layer 16 is less than 0.03 MPa, the first adhesive layer 16 cannot maintain its shape, and therefore the protective member 5 cannot be reliably formed. On the other hand, if the tensile modulus E of the first adhesive layer 16 is 0.15 MPa or more, the first adhesive layer 16 cannot sufficiently alleviate the stress applied to the organic EL panel member 4, and therefore damage to the thin-film sealing layer 15 in the organic EL panel member 4 cannot be suppressed.

[0073] The tensile modulus E of the first adhesive layer 16 is preferably 0.06 MPa or more, and preferably 0.12 MPa or less.

[0074] In the case (2-1), there are no limitations on the tensile modulus E of the second adhesive layer 18. The tensile modulus E of the second adhesive layer 18 is, for example, 0.03 MPa or more, and, for example, 0.45 MPa or less.

[0075] <Case (2-2)> In the case (2-2), the second adhesive layer 18 has a tensile modulus E of 0.03 MPa or more and less than 0.15 MPa. Therefore, the second adhesive layer 18 is relatively soft. Therefore, the second adhesive layer 18 can relieve the stress along the second direction received from the metal plate 6. As a result, damage to the thin-film sealing layer 15 in the organic EL panel member 4 can be suppressed. Note that if the tensile modulus E of the second adhesive layer 18 is less than 0.03 MPa, the second adhesive layer 18 cannot maintain its shape, and therefore the protective member 5 cannot be reliably formed. On the other hand, if the tensile modulus E of the second adhesive layer 18 is 0.15 MPa or more, the second adhesive layer 18 cannot sufficiently relieve the stress applied to the organic EL panel member 4, and therefore damage to the thin-film sealing layer 15 in the organic EL panel member 4 cannot be suppressed.

[0076] In the case (2-2), there are no limitations on the tensile modulus E of the first adhesive layer 16. The tensile modulus E of the first adhesive layer 16 is, for example, 0.03 MPa or more, and, for example, 0.45 MPa or less.

[0077] [Case (3)] In case (3), the tensile modulus E of the second adhesive layer 18 at 25°C is 0.03 MPa or more and 0.15 MPa or less. In case (3), the tensile modulus E of the base material 17 at 25°C is 10 GPa or more and 15 GPa or less. Because the base material 17 is relatively hard, the base material 17 itself acts to suppress lateral displacement. Therefore, the base material 17 and the soft second adhesive layer 18 cooperate to relieve stress in the organic EL panel member 4. Therefore, damage to the thin-film sealing layer 15 in the organic EL panel member 4 can be suppressed.

[0078] On the other hand, in case (3), if the tensile modulus E of the second adhesive layer 18 exceeds 0.15 MPa, the second adhesive layer 18 becomes too hard and the base material 17 and the second adhesive layer 18 cannot cooperate to relieve stress, and damage to the thin-film sealing layer 15 in the organic EL panel member 4 cannot be suppressed.

[0079] If the tensile modulus E of the second adhesive layer 18 is less than 0.03 MPa, the second adhesive layer 18 will not be able to maintain its shape, and therefore the protective member 5 will not be able to be formed reliably.

[0080] The tensile modulus E of the second adhesive layer 18 is preferably 0.06 MPa or more, and is preferably 0.42 MPa or less, and more preferably 0.12 MPa or less.

[0081] There are no limitations on the tensile modulus E of the first adhesive layer 16. The tensile modulus E of the first adhesive layer 16 is, for example, 0.03 MPa or more and, for example, 0.45 MPa or less.

[0082] The organic EL display device 1 is bent 100,000 times or more in the following bending test, for example.

[0083] <Bending test> As shown by the imaginary lines in Figure 3A, one side portion 26 and the other side portion 27 on the back surface 41 (an example of the surface on one side in the thickness direction) of the metal plate 6 are fixed to the surface of a first support plate 45 (imaginary line) and the surface of a second support plate 46 (imaginary line) that is spaced 16 mm apart from the one side portion 26 in the direction extending therefrom.

[0084] Next, the first support plate 45 and the second support plate 46 are moved parallel to each other while facing each other, and the organic EL display device 1 is bent so that the opposing distance between the back surface 41 of one side portion 26 and the back surface 41 of the other side portion 27 of the organic EL display device 1 becomes 2 mm, and so that the maximum distance between the opposing back surfaces 41 in the thickness direction at the middle portion 29 of the organic EL display device 1 exceeds 2 mm. The number of bends until the thin-film encapsulating layer 15 is damaged is determined.

[0085] If the number of flexing cycles is 100,000 or more, damage to thin film sealing layer 15 can be further suppressed.

[0086] <Effects of one embodiment> In this organic EL display device 1, as described above, the base material 17 has the desired tensile modulus E, and the first adhesive layer 16 or the second adhesive layer 18 has the desired tensile modulus E, so even if the organic EL display device 1 is bent, damage to the thin-film sealing layer 15 in the adjacent portion 31 including the boundary portion 28 can be suppressed.

[0087] Even if the number of flexing times in the above-mentioned flexing test is 100,000 or more, damage to thin film encapsulating layer 15 can be suppressed.

[0088] <Modification> In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, each modification can achieve the same effects as those in the above-described embodiment unless otherwise specified. Furthermore, the embodiment and its modifications can be combined as appropriate.

[0089] A transparent conductive film (not shown) can be provided on the front side of the thin film sealing layer 15 and on the back side of the optical adhesive layer 13. The transparent conductive film includes at least a transparent conductive layer. Specifically, the transparent conductive film includes a transparent conductive layer and a transparent substrate layer. Examples of materials for the transparent conductive layer include complex oxides. Examples of complex oxides include indium tin complex oxide (ITO). Examples of materials for the transparent substrate layer include the same materials as those for the substrate 17 described above. The organic EL display device 1 of this modified example functions as a touch panel type input display device. [Example]

[0090] The present invention will be described in more detail below with reference to Preparation Examples, Production Examples, Examples, and Comparative Examples. The present invention is not limited to these Preparation Examples, Production Examples, Examples, and Comparative Examples. The specific numerical values of the blending ratios (ratios), physical property values, parameters, etc. used in the following description can be substituted with the upper limit (a numerical value defined as "equal to or less than") or lower limit (a numerical value defined as "equal to or more than") of the corresponding blending ratios (ratios), physical property values, parameters, etc. described in the "Mode for Carrying Out the Invention" above.

[0091] Each layer in the organic EL display device 1 was prepared and evaluated as follows.

[0092] [Preparation of Substrate 17] Substrates A to C were prepared as follows.

[0093] [Base material A] A substrate 17 made of PET (trade name "Lumirror S10", manufactured by Toray Industries, Inc.) was prepared as substrate A. The thickness of substrate A was 50 μm.

[0094] [Base material B] A substrate 17 made of polyimide resin (trade name "C_50", manufactured by KOLON) was prepared as substrate B. The thickness of substrate B was 50 μm.

[0095] [Base material C] A substrate 17 made of polyimide resin (trade name "UPILEX 50S", manufactured by Ube Industries, Ltd.) was prepared as substrate C. The thickness of substrate C was 50 μm.

[0096] [Tensile modulus of base material E] The tensile modulus E at 25°C was measured for each of substrates A to C. Specifically, each of substrates A to C was machined into a rectangular shape with a width of 10 mm and a length of 100 mm. The substrate was placed in a tensile tester (Shimadzu Corporation, product name "Autograph AG-IS"), and the strain and stress were measured when the substrate was pulled at 200 mm / min. The tensile modulus E for each of substrates A to C was calculated from the slope of the curve in the strain range of 0.05% to 0.25%.

[0097] [Preparation of adhesive sheet] Adhesive sheets A to F were prepared as follows.

[0098] Preparation Example 1 [Preparation of Adhesive Sheet A] 43 parts by mass of lauryl acrylate (LA), 44 parts by mass of 2-ethylhexyl acrylate (2EHA), 6 parts by mass of 4-hydroxybutyl acrylate (4HBA), 7 parts by mass of N-vinyl-2-pyrrolidone (NVP), and 0.015 parts by mass of BASF's "Irgacure 184" were blended and polymerized by exposure to ultraviolet light to obtain a base polymer composition (polymerization rate: approximately 10%).

[0099] Separately, 60 parts by weight of dicyclopentanyl methacrylate (DCPMA), 40 parts by weight of methyl methacrylate (MMA), 3.5 parts by weight of α-thioglycerol, and 100 parts by weight of toluene were mixed and stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) was added and reacted at 70°C for 2 hours, then the temperature was raised to 80°C and reacted for 2 hours. The reaction solution was then heated to 130°C, and the toluene, α-thioglycerol, and unreacted monomers were dried and removed to obtain a solid acrylic oligomer. The acrylic weight-average molecular weight was 5100. The glass transition temperature (Tg) was 130°C.

[0100] To 100 parts by mass of the solid content of the base polymer composition, 0.07 parts by mass of 1,6-hexanediol diacrylate (HDDA), 1 part by mass of an acrylic oligomer, and 0.3 parts by mass of a silane coupling agent (product name: KBM403, 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) were added, and then these were mixed uniformly to prepare a pressure-sensitive adhesive composition.

[0101] The adhesive composition was applied to the surface of a release sheet made of PET film ("Diafoil MRF75" manufactured by Mitsubishi Chemical Corporation), and then another release sheet made of PET film ("Diafoil MRF75" manufactured by Mitsubishi Chemical Corporation) was attached to the coating film. The coating film was then irradiated with ultraviolet light to prepare a 15 μm thick adhesive sheet A.

[0102] Preparation Example 2 [Preparation of Adhesive Sheet B] A four-neck flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser was charged with 99 parts by weight of butyl acrylate (BA) and 1 part by weight of 4-hydroxybutyl acrylate (HBA). Furthermore, 0.1 parts by weight of 2,2'-azobisisobutyronitrile was charged together with ethyl acetate per 100 parts by weight of the monomer mixture. Nitrogen gas was introduced to replace the atmosphere with nitrogen while gently stirring, and the liquid temperature in the flask was maintained at around 55°C for 7 hours to allow the polymerization reaction. Ethyl acetate was then added to the resulting reaction solution to prepare a solution of an acrylic-based polymer with a weight-average molecular weight of 1.6 million, adjusted to a solids concentration of 30%.

[0103] An acrylic pressure-sensitive adhesive composition was prepared by blending 0.1 part by mass of an isocyanate crosslinking agent (trade name: Takenate D110N, trimethylolpropane-modified xylylene diisocyanate, manufactured by Mitsui Chemicals, Inc.), 0.3 part by mass of benzoyl peroxide (trade name: Niper BMT, manufactured by NOF Corporation), and 0.08 part by mass of a silane coupling agent (trade name: KBM403, 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) with 100 parts by mass of the solids content of the acrylic base polymer solution.

[0104] The acrylic adhesive composition was uniformly applied to the surface of a release sheet made of PET film using a fountain coater, and then dried for 2 minutes in an air-circulating constant temperature oven at 155°C to prepare an adhesive sheet B having a thickness of 15 μm.

[0105] Preparation Example 3 [Preparation of Adhesive Sheet C] A 15 μm thick adhesive sheet B was prepared in the same manner as in Preparation Example 2, except that a mixed solvent of ethyl acetate and toluene (95 / 5 by mass ratio) was used instead of ethyl acetate.

[0106] Preparation Example 4 [Preparation of Adhesive Sheet D] Pressure-sensitive adhesive sheet D was prepared in the same manner as in Preparation Example 1, except that the thickness was changed to 50 μm.

[0107] Preparation Example 5 [Preparation of Adhesive Sheet E] Pressure-sensitive adhesive sheet E was prepared in the same manner as in Preparation Example 2, except that the thickness was changed to 50 μm.

[0108] Preparation Example 6 [Preparation of Adhesive Sheet F] Pressure-sensitive adhesive sheet F was prepared in the same manner as in Preparation Example 3, except that the thickness was changed to 50 μm.

[0109] [Tensile modulus of elasticity E of adhesive layer] The release sheets were peeled off from each of the adhesive sheets A to F, and the tensile modulus E of the resulting adhesive layers at 25°C was measured. Specifically, each of the adhesive sheets A to F was contoured into a rectangular shape 10 mm wide and 100 mm long, and the release sheets were peeled off to leave rectangular adhesive layers 10 mm wide and 100 mm long. Multiple sheets of the resulting adhesive layers were laminated to create a measurement sample with a thickness of 100 μm. The measurement sample of the adhesive layer was placed in a tensile tester (Shimadzu Corporation, product name "Autograph AG-IS"), and the strain and stress were measured when pulled at 200 mm / min. The tensile modulus E of the adhesive layer was calculated from the slope of the curve in the strain range of 0.05% to 0.25%. The results are shown in Table 2.

[0110] The tensile modulus E of the adhesive layer was calculated from the shear storage modulus G' as follows. [Shear storage modulus G' of adhesive layer] The release sheet was peeled off from each of the adhesive sheets A to F, and multiple adhesive sheets were stacked together to prepare a test sample with a thickness of 100 μm. This test sample was punched out into a disk with a diameter of 7.9 mm, sandwiched between parallel plates, and subjected to dynamic viscoelasticity measurement under the following conditions using an Advanced Rheometric Expansion System (ARES) manufactured by Rheometric Scientific, and the shear storage modulus G' was read from the measurement results. (Measurement conditions) Deformation mode: Torsion Measurement temperature: -40℃~150℃ Heating rate: 5°C / min Measurement frequency: 1Hz

[0111] Next, the composition of the sample was measured and the Poisson's ratio ν was determined. Since the relationship E' = 2G' (1 + ν) holds between the tensile storage modulus E' and the shear modulus G', the tensile storage modulus E' was calculated from the shear storage modulus G' and the Poisson's ratio ν determined above. Since it is generally known that there is little difference between the tensile storage modulus E' and the tensile storage modulus E in a room temperature environment, the tensile storage modulus E' determined above was set to be the same value as the tensile modulus E.

[0112] [Fabrication of window component 2] A window member 2 including a hard coat layer 7 (thickness 10 μm), a transparent polyimide film (manufactured by KOLON, product name "C_80", thickness 80 μm) as a window film 8, and a window adhesive layer 9 was prepared.

[0113] Specifically, according to the formulation described in Example 1 of JP 2020-064236 A, a 10 μm-thick hard coat layer 7 was formed on the surface of a window film 8. Then, the pressure-sensitive adhesive sheet A of Preparation Example 1 was attached to the back surface of the window film 8. In this way, a window member 2 was prepared that had the hard coat layer 7, the window film 8, and the window pressure-sensitive adhesive layer 9, in that order in the thickness direction.

[0114] [Fabrication of Optical Element 3] An optical member 3 was prepared, which included a polarizer protective film 10, a polarizing film 25, and an optical adhesive layer 13 in that order in the thickness direction. The polarizing film 25 was produced by bonding a polarizer 11 and an optical compensation layer 12 together. Details of each layer are described below.

[0115] (Preparation of Polarizer Protective Film 10) Methacrylic resin pellets having glutarimide ring units were extruded and formed into a film, which was then stretched to prepare a polarizer protective film 10 having a thickness of 40 μm.

[0116] (Preparation of polarizing film 25) A 5 μm-thick polarizer 11 was prepared according to Example 1 of JP 2020-149065 A. Separately, an optical compensation layer 12 made of a 6 μm-thick retardation film was prepared according to Example 1 of JP 2019-218513 A. Subsequently, the above-described polarizer 11 and the above-described optical compensation layer 12 were bonded together using the adhesive described in JP 2019-218513 A, thereby producing a polarizing film 25.

[0117] [Example of manufacturing the dummy panel member 40] An example of manufacturing a dummy panel member 40 that can be used as a substitute for the organic electroluminescence panel member 4 will be described below.

[0118] Preparation example 1 [Fabrication of a dummy panel member 40 having a panel body 14 with a thickness of 25 μm] A polyimide resin film (Ube Industries, Ltd., "UPILEX 25S," 25 μm thick) was prepared as the panel body 14. Next, a 50 nm thick ITO layer was formed as an example of an electrode (surface member) on the upper surface of the polyimide resin film by sputtering. Next, they were subjected to a heat treatment at 130°C for 90 minutes to crystallize the ITO layer. In this way, a dummy panel member 40 with a surface member was produced. The dummy panel member 40 is a substitute for the organic EL panel member 4, and its physical properties are input into the bending simulation described below.

[0119] Preparation example 2 [Fabrication of a dummy panel member 40 having a panel body 14 with a thickness of 30 μm] A dummy panel member 40 was produced in the same manner as in Production Example 1. However, the thickness of the panel body 14 was changed to 30 μm.

[0120] [Preparation of Metal Plate 6] As the metal plate 6, a stainless steel plate having a thickness of 30 μm was prepared.

[0121] (Manufacturing of organic EL display device 1) Example 1 A first adhesive layer 16 made of adhesive sheet A of Preparation Example 1 and a second adhesive layer 18 made of adhesive sheet D of Preparation Example 4 were arranged on the front and back surfaces of a base material 17 made of base material A. In this way, a protective member 5 was produced which was provided with the first adhesive layer 16, base material 17, and second adhesive layer 18 in that order in the thickness direction, as shown in FIG.

[0122] Thereafter, the window member 2, the optical member 3, the dummy panel member 40 of Preparation Example 1, the protective member 5, and the metal plate 6 were laminated together to manufacture the organic EL display device 1.

[0123] Examples 2 to 22 and Comparative Examples 1 to 32 An organic EL display device 1 was manufactured in the same manner as in Example 1. However, as shown in Tables 3 to 8, the first adhesive layer 16, the base material 17, the second adhesive layer 18, and / or the dummy panel member 40 were changed.

[0124] Tables 3 to 8 show the tensile modulus E of the first adhesive layer 16, the tensile modulus E of the substrate 17, the tensile modulus E of the second adhesive layer 18, and the thickness of the panel body 14 in Examples 2 to 22 and Comparative Examples 1 to 32.

[0125] [Distortion measurement] A bending simulation was performed on the organic EL display device 1 of each example and comparative example to determine the strain on the boundary portion 28. The results are shown in Tables 3 to 8. Details of the bending simulation are described below. In Tables 3 to 8, the numerical values in the column below the example or comparative example column indicate the strain in %.

[0126] Simulation software: MSC Software's Marc Simulation model and size: The length was set to 100 mm, and the thickness was set to the total thickness of each component in the cross-sectional configuration. A mesh was created in two dimensions: thickness and length.

[0127] <Bending simulation> The following bending simulation was performed. In the bending simulation, the bending center was set at a point 50 mm from each of the longitudinal end edges. The areas from each of the longitudinal end edges to a point 42 mm from the end edges toward the middle portion 24 were designated as one side portion 26 and the other side portion 27, and the surfaces of the one side portion 26 and the other side portion 27 facing the metal plate 6 (the surfaces on one side in the thickness direction of the metal plate 6) were fixed to the one-side curve and the other-side curve, respectively. Next, as shown in FIG. 3B , the one side portion 26 and the one-side curve were rotated 180 degrees about the center, and the one side portion 26 and the other side portion 27 were overlapped. The distance between the back surface of the one side portion 26 and the back surface of the other side portion 27 was set to 2 mm, and the outer diameter of the bent middle portion 24 was greater than 2 mm.

[0128] <Input of physical properties of each layer into the simulation> (i) Hard coat layer 7, window film 8, polarizer protective film 10, polarizer 11, panel body 14, substrate 17, metal plate 6 Tensile tests were conducted at 25°C for each of the hard coat layer 7, window film 8, polarizer protective film 10, polarizer 11, panel body 14, substrate 17, and metal plate 6 to obtain stress-strain curves. Strain and stress were converted to true strain (ln(strain + 1)) and true stress (stress(strain + 1)), respectively. The type was entered as "signed_eq_mechanical_Strain" in the simulation table. The material type for the relevant part of the mesh was entered as "hypoelastic," and the stress-strain curve for the relevant material was selected from the table.

[0129] (ii) Each adhesive layer (window adhesive layer 9, optical adhesive layer 13, first adhesive layer 16, second adhesive layer 1) A tensile test was carried out on each of the window adhesive layer 9, the optical adhesive layer 13, the first adhesive layer 16, and the second adhesive layer 18, and a stress-strain curve was obtained. The stress-strain curve of the tensile test was fitted with the Mooney-Rivlin equation (2) below, and the coefficient C 10 , C 01 , C 11The type of material property for the relevant part of the mesh is entered as "Mooney" and the calculated coefficient C 10 , C 01 , C 11 I entered:

number

[0130] (iii) Optical compensation layer 12 and ITO layer For the optical compensation layer 12, the type of material property of the corresponding part of the mesh was entered as "isotropic elastoplastic," and the elastic modulus calculated from a tensile test of the optical member 3 including the optical compensation layer 12 was entered. For the ITO layer, the type of material property of the corresponding part of the mesh was entered as "isotropic elastoplastic," and the elastic modulus calculated from a tensile test of the dummy panel member 40 including the ITO layer was entered.

[0131] <Distortion calculation> The maximum value of the strain in the second direction at the boundary 28 on the surface of the dummy panel member 40 was calculated by the following method.

[0132] (i) Calculate the coordinates of the contact points after bending Displacement X and Displacement Y output the displacement from the coordinate before bending to the coordinate after bending, and the coordinate of the contact point after bending is calculated from the coordinate before bending and the displacement. Specifically, the coordinate after bending is calculated using the following formula. Coordinates before bending + displacement = coordinates after bending

[0133] (ii) Calculate the distance between the contact points after bending The distance between adjacent contact points in the second direction was calculated. The distance between the two points is ((X1-X2) 2 +(Y1-Y2) 2 ) 1 / 2 ) where X1, X2, Y1 and Y2 are as follows: X1: Displacement X coordinate at the contact point before bending X2: Displacement X coordinate at the contact point after bending Y1: Displacement Y coordinate at the contact point before bending Y2: Displacement X coordinate at the contact point after bending

[0134] (iii) Calculate the strain after bending The distance between adjacent contact points in the second direction before bending was also calculated in the same manner as the calculation of the distance between contact points after bending, as described above, and the distortion after bending was calculated from the distance between contact points before and after bending. Specifically, the strain was calculated using the following formula: Distortion (%) = ((distance between contacts after bending / distance between contacts before bending) - 1) x 100

[0135] <Distortion evaluation> The Examples and Comparative Examples listed in Table 3 correspond to Case (1) because the tensile modulus E of the base material A is 3 GPa. In all of Examples 1 to 3, the tensile modulus E of the first adhesive layer 16 is 0.03 MPa or more and less than 0.15 MPa. Therefore, the strains in Examples 1 to 3 are smaller than those in Comparative Examples 1 to 6.

[0136] In Examples 12 to 14 shown in Table 6, the tensile modulus E of the first adhesive layer 16 is 0.03 MPa or more and less than 0.15 MPa, and the strain is smaller than that of Comparative Examples 17 to 22.

[0137] The Examples and Comparative Examples listed in Table 4 correspond to Case (2) because the tensile modulus E of the substrate B is 7 GPa. In Examples 4 to 8, the tensile modulus E of the first adhesive layer 16 or the second adhesive layer 18 is 0.03 MPa or more and less than 0.15 MPa. Therefore, the strains in Examples 4 to 8 are smaller than those in Comparative Examples 7 to 10.

[0138] In Examples 15 to 19 listed in Table 7, the tensile modulus E of the first adhesive layer 16 or the second adhesive layer 18 is 0.03 MPa or more and less than 0.15 MPa, and the distortion is smaller than that of Comparative Examples 23 to 26.

[0139] The Examples and Comparative Examples listed in Table 5 correspond to Case (3) because the tensile modulus E of the substrate C is 12 GPa. In Examples 9 to 11, the tensile modulus E of the second adhesive layer 18 is 0.03 MPa or more and 0.15 MPa or less. Therefore, the strain in Examples 9 to 11 is smaller than that in Comparative Examples 11 to 16.

[0140] In Examples 20 to 22 listed in Table 8, the tensile modulus E of second adhesive layer 18 is 0.03 MPa or more and 0.15 MPa or less, and the strain is smaller than those of Comparative Examples 27 to 32.

[0141] [Table 1]

[0142] [Table 2]

[0143] [Table 3]

[0144] [Table 4]

[0145] [Table 5]

[0146] [Table 6]

[0147] [Table 7]

[0148] [Table 8] [Explanation of symbols]

[0149] 1 Organic EL display device 4. Organic EL panel components 5 Protective materials 6 metal plate 8. Window Film 16 1st adhesive layer 17 Base material 18 Second adhesive layer 26 One side 27 Other side 29 Central part 41 Back side 45 1st support plate 46 Second support plate

Claims

1. An organic electroluminescence display device including an organic electroluminescence panel member, a first adhesive layer, a base material, a second adhesive layer, and a metal plate in this order toward one side in a thickness direction, The substrate has a tensile modulus E at 25°C of 1 GPa or more and 15 GPa or less, When the tensile modulus E of the base material at 25°C is 1 GPa or more and less than 5 GPa (1), the tensile modulus E of the first adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, In the case where the tensile modulus E of the base material at 25°C is 5 GPa or more and less than 10 GPa (2), the tensile modulus E of the first adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, or the tensile modulus E of the second adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, In the case where the tensile modulus E of the base material at 25°C is 10 GPa or more and 15 GPa or less (3), the tensile modulus E of the second adhesive layer at 25°C is 0.03 MPa or more and 0.15 MPa or less, the metal plate is stainless steel and forms the entire surface of one side in a thickness direction of the organic electroluminescence display device; The thickness of the metal plate is 5 μm or more and 100 μm or less, The organic electroluminescence display device, wherein the metal plate has a tensile modulus E of 50 GPa or more and 500 GPa or less.

2. Further comprising a window member and an optical member, the window member, the optical member, the organic electroluminescence panel member, the first adhesive layer, the base material, the second adhesive layer, and the metal plate are arranged in this order toward one side in the thickness direction, extending in one direction perpendicular to the thickness direction, the first end portion has one side portion, another side portion spaced apart from the one side portion, and an intermediate portion located therebetween in the extending direction; The one side portion and the other side portion on one surface of the metal plate in the thickness direction are fixed to a surface of a first support plate and a surface of a second support plate spaced 16 mm from the one side portion in the extension direction, 2. The organic electroluminescent display device according to claim 1, wherein the organic electroluminescent display device is bent 100,000 times or more in a bending test in which the first support plate and the second support plate are moved in a facing, parallel relationship, such that the opposing distance between one thickness-wise surface of one side of the organic electroluminescent display device and one thickness-wise surface of the other side of the organic electroluminescent display device is 2 mm, and the maximum distance between the thickness-wise surfaces opposing each other in the thickness direction at the center of the organic electroluminescent display device exceeds 2 mm.

3. A protective member used in the organic electroluminescence display device according to claim 1, A first adhesive layer, a base material, and a second adhesive layer are provided in this order toward one side in a thickness direction, The substrate has a tensile modulus E at 25°C of 1 GPa or more and 15 GPa or less, When the tensile modulus E of the base material at 25°C is 1 GPa or more and less than 5 GPa (1), the tensile modulus E of the first adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, In the case where the tensile modulus E of the base material at 25°C is 5 GPa or more and less than 10 GPa (2), the tensile modulus E of the first adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, or the tensile modulus E of the second adhesive layer at 25°C is 0.03 MPa or more and less than 0.15 MPa, A protective member in which, when the tensile modulus E of the base material at 25°C is 10 GPa or more and 15 GPa or less (3), the tensile modulus E of the second adhesive layer at 25°C is 0.03 MPa or more and 0.15 MPa or less.

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