Flexible display device metal support, method of manufacturing the same, and flexible display device

Abstract

To provide a flexible display device metal support capable of reducing a curvature radius of a bent portion of a flexible display device, a method of manufacturing the same, and a flexible display device.SOLUTION: A flexible display device metal support 10 is provided, comprising a first metal layer 20 having a first surface 20a and a second surface 20b, and a second metal layer 30 stacked on the second surface 20b of the first metal layer 20. A main metal material constituting the first metal layer 20 is different from a main metal material constituting the second metal layer 30. The second metal layer 30 has a first opening 31.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a metal support for a flexible display device and a method for manufacturing the same, and a flexible display device. [Background technology]

[0002] In recent years, foldable display devices have become known for use in, for example, smartphones, tablets, etc. As such display devices, there are flexible display devices that have a bendable portion in a portion thereof (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6603764 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for a smaller shape of the bent portion when a flexible display device is folded. In other words, there is a demand for a smaller radius of curvature of the bent portion. However, when the shape of the bent portion is made smaller, it becomes difficult to maintain the strength of the bent portion.

[0005] The present disclosure provides a metal support for a flexible display device, which is capable of reducing the radius of curvature of the bent portion of the flexible display device, a method for manufacturing the same, and a flexible display device. [Means for solving the problem]

[0006] The embodiments of the present disclosure relate to the following [1] to

[12] .

[0007] [1] A metal support for a flexible display device, comprising: a first metal layer having a first surface and a second surface; and a second metal layer laminated on the second surface of the first metal layer, wherein a main metal material constituting the first metal layer is different from a main metal material constituting the second metal layer, and the second metal layer has a first opening.

[0008] [2] The metal support for a flexible display device according to [1], further comprising a third metal layer laminated on the first surface of the first metal layer.

[0009] [3] The metal support for a flexible display device according to [2], wherein the third metal layer has a second opening.

[0010] [4] A metal support for a flexible display device described in [2] or [3], wherein at least a portion of the first opening of the second metal layer and at least a portion of the second opening of the third metal layer overlap in a planar view.

[0011] [5] A metal support for a flexible display device described in any one of [2] to [4], wherein at least a portion of the first opening of the second metal layer and at least a portion of the second opening of the third metal layer are misaligned in a planar view.

[0012] [6] The metal support for a flexible display device according to [2], wherein the third metal layer has no openings.

[0013] [7] A metal support for a flexible display device described in any one of [1] to [6], wherein the second metal layer has a pattern-shaped portion around the first opening, and the pattern-shaped portion includes a portion formed in an island shape, a line shape or a mesh shape.

[0014] [8] A flexible display device comprising: a display member; and a metal support for a flexible display device according to any one of [1] to [7] that supports the display member.

[0015] [9] A method for manufacturing a metal support for a flexible display device, comprising the steps of: preparing a laminate having a first metal layer having a first side and a second side, and a second metal layer laminated on the second side of the first metal layer, wherein a main metal material constituting the first metal layer and a main metal material constituting the second metal layer are different from each other; providing a second protective layer having a second protective layer opening on the second metal layer of the laminate; and forming a first opening in the second metal layer by etching the second metal layer of the laminate.

[0016]

[10] The laminate further has a third metal layer laminated on the first surface of the first metal layer, and the method for manufacturing a metal support for a flexible display device described in [9] further includes a step of providing a first protective layer on the third metal layer.

[0017]

[11] The method for manufacturing a metal support for a flexible display device described in

[10] , wherein the first protective layer has a first protective layer opening, and in the etching process, a second opening is formed in the third metal layer.

[0018]

[12] The method for manufacturing a metal support for a flexible display device described in

[10] , wherein the first protective layer does not have an opening, and in the etching process, no opening is formed in the third metal layer. Effect of the Invention

[0019] According to the present disclosure, the radius of curvature of the curved portion of a flexible display device can be made smaller. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view showing a flexible display device according to an embodiment. [Diagram 2] FIG. 2 is a plan view showing a flexible display device according to an embodiment. [Diagram 3]FIG. 3 is a cross-sectional view (cross-sectional view taken along line III-III in FIG. 2) showing the flexible display device (in an unfolded state) according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a flexible display device (in a folded state) according to an embodiment. [Diagram 5] FIG. 5 is a plan view showing a metal support for a flexible display device according to an embodiment. [Figure 6] FIG. 6 is a partial cross-sectional view showing a metal support for a flexible display device according to an embodiment (a cross-sectional view taken along line VI-VI in FIG. 5). [Figure 7] 7(a) to (c) are plan views showing modified examples of a metal support for a flexible display device. [Figure 8] 8(a) to 8(d) are cross-sectional views showing a method for manufacturing a metal support for a flexible display device according to an embodiment. [Figure 9] 9(a) to 9(d) are cross-sectional views showing modified metal supports for flexible display devices. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] An embodiment of the present disclosure will be described with reference to Figures 1 to 9. In the following figures, the same parts are denoted by the same reference numerals, and some detailed description may be omitted.

[0022] In this specification, the first direction D1 refers to a direction located on a plane parallel to the main surface of the metal support 10 for a flexible display device or the flexible display device 70 and perpendicular to the folding center line FL. The second direction D2 refers to a direction located on a plane parallel to the main surface of the metal support 10 for a flexible display device or the flexible display device 70 and parallel to the folding center line FL. The first direction D1 and the second direction D2 may be parallel to each side of the metal support 10 for a flexible display device or the flexible display device 70. The first direction D1 and the second direction D2 are orthogonal to each other. The third direction D3 refers to a direction perpendicular to both the first direction D1 and the second direction D2 and parallel to the thickness direction of the metal support 10 for a flexible display device or the flexible display device 70.

[0023] (Configuration of metal support for flexible display device) First, an outline of a flexible display device according to the present embodiment will be described with reference to Figures 1 to 4. Figures 1 to 4 are diagrams showing a flexible display device according to the present embodiment.

[0024] The flexible display device 70 shown in FIG. 1 and FIG. 2 may be, for example, an organic electroluminescence (EL) display device. The flexible display device 70 is flexible and has a foldable structure. That is, the flexible display device 70 can be in a folded state (see FIG. 4) in a folded state and in an unfolded state (see FIG. 2 and FIG. 3) in an unfolded state. The folded state is a state in which the flexible display device 70 is folded around a folding center line FL. In the folded state, the display members 71 are folded in a direction in which the outer surfaces of the display members 71 approach each other. However, this is not limited to this, and the display members 71 may be folded in a direction in which the outer surfaces of the housings 78 approach each other. The unfolded state is a state in which the flexible display device 70 is opened without being folded. In the unfolded state, the entire surface of the display member 71 is substantially located on the same plane. Such a flexible display device 70 may be a thin electronic device having a portion for displaying an image. Such an electronic device may be, for example, a mobile terminal device such as a smartphone or a tablet.

[0025] 3, the flexible display device 70 includes a display member 71 and a metal support 10 for a flexible display device (hereinafter, simply referred to as the metal support 10) that supports the display member 71. A buffer layer 76 such as a cushion sheet is provided between the display member 71 and the metal support 10. A heat dissipation layer 77 is disposed on the surface of the metal support 10 opposite to the display member 71. Furthermore, the display member 71, the buffer layer 76, the metal support 10, and the heat dissipation layer 77 are supported by a housing 78.

[0026] The display member 71 has a supporting substrate 72, a thin film transistor (TFT) 73, an organic EL element 74, and a sealing resin 75. The thin film transistor 73 is disposed on the supporting substrate 72. The organic EL element 74 is disposed on the thin film transistor 73. The sealing resin 75 is disposed on the organic EL element 74.

[0027] The support base material 72 supports the entire display member 71 and may be a flexible film. The support base material 72 may be made of a synthetic resin material such as polyethylene terephthalate. The thin film transistor 73 drives the organic EL element 74 and controls the voltage applied to the electrode of the organic EL element 74. The organic EL element 74 displays an image or the like by emitting light by itself. The organic EL element 74 is electrically connected to the thin film transistor 73. The organic EL element 74 may be called a light-emitting portion. The organic EL element 74 may have a reflective electrode, an organic light-emitting layer, and a transparent electrode, which are not shown. The sealing resin 75 seals the organic EL element 74 and protects the organic EL element 74. The display member 71 is not limited to an organic EL display device. For example, the display member 71 may be another display device having a function of emitting light by itself. The display member 71 may be a micro LED display device including a micro LED element (light emitter).

[0028] The buffer layer 76 is a layer that relieves stress applied to the display member 71 when the flexible display device 70 is bent. The buffer layer 76 may be a layer of a resin material having elasticity, such as silicone resin, polyurethane resin, or epoxy resin. The metal support 10 is a member that increases the bending strength when the flexible display device 70 is bent. The configuration of the metal support 10 will be described later.

[0029] The heat dissipation layer 77 is a layer for dissipating heat from the display member 71 to the outside. The heat dissipation layer 77 may be a metal layer such as copper or nickel. The heat dissipation layer 77 may also be a plating layer produced by electrolytic plating. The housing 78 houses and protects the display member 71, the buffer layer 76, the metal support 10, and the heat dissipation layer 77. The housing 78 has a structure that allows it to be folded about a folding center line FL.

[0030] The flexible display device 70 has a bent region BA and a non-bent region NA. The bent region BA is a region that is physically deformed when the flexible display device 70 is in a bent state (see FIG. 4). The bending center line FL is located at approximately the center of the bent region BA. The non-bent region NA is a region that is not substantially deformed when the flexible display device 70 is in a bent state (see FIG. 4). In the first direction D1, the non-bent region NA is located on both sides of the bent region BA. The lengths of the two non-bent regions NA along the first direction D1 may be approximately the same. Not limited to this, the lengths of the two non-bent regions NA along the first direction D1 may be different from each other. The bent region BA is located at the center of the flexible display device 70 in the first direction D1. Not limited to this, the bent region BA may be located at a position other than the center of the flexible display device 70 in the first direction D1.

[0031] (Configuration of metal support for flexible display device) Next, an outline of the metal support for a flexible display device according to the present embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are diagrams showing the metal support for a flexible display device according to the present embodiment.

[0032] As shown in FIG. 5 and FIG. 6, the metal support 10 includes a first metal layer 20, a second metal layer 30, and a third metal layer 40. That is, the metal support 10 is composed of a three-layer laminate. The first metal layer 20 has a first surface 20a and a second surface 20b. The first surface 20a faces the display member 71 of the flexible display device 70. The second surface 20b faces the heat dissipation layer 77 of the flexible display device 70. The first surface 20a and the second surface 20b are parallel to a plane formed by the first direction D1 axis and the second direction D2 axis, respectively. The second metal layer 30 is disposed on the second surface 20b of the first metal layer 20. The third metal layer 40 is laminated on the first surface 20a of the first metal layer 20. The main metal material constituting the first metal layer 20 and the main metal material constituting the second metal layer 30 are different from each other. The second metal layer 30 has a first opening 31 that opens toward the opposite side to the first metal layer 20 .

[0033] The metal support 10 has a bent region BA and a non-bent region NA. The bent region BA is a region that physically deforms when the flexible display device 70 is in a bent state (see FIG. 4). The folding center line FL is located approximately at the center of the bent region BA. The non-bent region NA is a region that does not substantially deform when the flexible display device 70 is in a bent state (see FIG. 4). The bent region BA and the non-bent region NA respectively correspond to the bent region BA and the non-bent region NA of the flexible display device 70 described above.

[0034] The first metal layer 20 is a member that enhances the bending strength when the flexible display device 70 is bent. The first metal layer 20 also holds the second metal layer 30 and the third metal layer 40. The first metal layer 20 has a rectangular shape in a plan view. This rectangle has a pair of long sides parallel to the first direction D1 and a pair of short sides parallel to the second direction D2. However, this is not limited to this, and a pair of short sides may be parallel to the first direction D1 and a pair of long sides may be parallel to the second direction D2. Each corner of the rectangle may be rounded. The first metal layer 20 may also be a square, polygon, or circle in a plan view. The planar shape of the first metal layer 20 may correspond to the planar shape of the flexible display device 70. In this case, the planar shape of the first metal layer 20 may be the same as the planar shape of the flexible display device 70. Alternatively, the planar shape of the first metal layer 20 may be smaller than the planar shape of the flexible display device 70.

[0035] The first metal layer 20 has a flexible, bendable thin plate shape. In this specification, "flexible" means "capable of being bent to a radius of curvature of at least 5.0 mm or less, preferably 3.0 mm or less."

[0036] The thickness T1 of the first metal layer 20 may be 10 μm or more, or may be 15 μm or more. By setting the thickness T1 of the first metal layer 20 to 10 μm or more, the bending strength of the first metal layer 20 can be maintained. The thickness T1 of the first metal layer 20 may be 40 μm or less, or may be 30 μm or less. By setting the thickness T1 of the first metal layer 20 to 40 μm or less, it is possible to prevent the flexible display device 70 incorporating the metal support 10 from becoming excessively thick.

[0037] The first metal layer 20 is made of metal. The first metal layer 20 includes a main metal material. An iron alloy such as stainless steel may be used as the main metal material of the first metal layer 20. When stainless steel is used as the main metal material of the first metal layer 20, the first metal layer 20 has good spring properties and is therefore easy to bend. In this specification, the term "main metal material" refers to a metal material that is contained in a certain member in an amount of more than 50 mass%, preferably more than 80 mass%.

[0038] The second metal layer 30 is laminated on the second surface 20b of the first metal layer 20. The second metal layer 30 is bonded to the first metal layer 20. The second metal layer 30 may be laminated on the first metal layer 20 by rolling bonding, diffusion bonding, or depositing metal by plating, as described below. The second metal layer 30 increases the strength of the metal support 10. The second metal layer 30 is provided at least in the curved region BA of the first metal layer 20. The second metal layer 30 may be provided on the entire second surface 20b of the first metal layer 20, including the curved region BA, or may be provided on a part of the second surface 20b of the first metal layer 20. The second metal layer 30 may be directly laminated on the second surface 20b of the first metal layer 20, or may be laminated on the first metal layer 20 via another layer. The thickness T2 of the second metal layer 30 may be 100 μm or less, or 50 μm or less. The thickness T2 of the second metal layer 30 may be smaller than the thickness T1 of the first metal layer 20.

[0039] The second metal layer 30 has a first opening 31 that opens toward the opposite side of the first metal layer 20. In this case, the first opening 31 is a through opening that penetrates the second metal layer 30 in the thickness direction. That is, a part of the second surface 20b of the first metal layer 20 is exposed to the outside through the first opening 31. The first opening 31 may be a non-through opening that does not penetrate the second metal layer 30 in the thickness direction as long as it opens toward the opposite side of the first metal layer 20. As shown in FIG. 5, the outer periphery of the first opening 31 does not necessarily have to be formed in a ring shape. That is, the first opening 31 may reach the outer edge of the second metal layer 30.

[0040] The second metal layer 30 has a first pattern shape portion 32 around the first opening 31. The first pattern shape portion 32 is provided at a position corresponding to the bending region BA. The first pattern shape portion 32 includes a first island portion 33 which is a portion formed in an island shape. The first pattern shape portion 32 has a first opening 31 and a plurality of first island portions 33 each having an annular periphery. A first opening 31 is formed around the first island portion 33. The first opening 31 surrounds the entire periphery of each first island portion 33. The first island portions 33 are arranged at intervals in each of the first direction D1 and the second direction D2. The plurality of first island portions 33 are aligned in both the first direction D1 and the second direction D2. That is, the plurality of first island portions 33 are arranged at intervals from each other along the first direction D1, and are also arranged at intervals from each other along the second direction D2. The interval P1 between the first island portions 33 in the first direction D1 may be 5 μm or more, or may be 10 μm or more. The interval P1 between the first island portions 33 in the first direction D1 may be 500 μm or less, or may be 100 μm or less. The interval P2 between the first island portions 33 in the second direction D2 may be 5 μm or more, or may be 10 μm or more. The interval P2 between the first island portions 33 in the second direction D2 may be 500 μm or less, or may be 100 μm or less.

[0041] Each of the first island portions 33 has a substantially square shape in plan view. However, each of the first island portions 33 may have, for example, a polygonal shape or a circular shape in plan view. The length L1 of the first island portion 33 along the first direction D1 may be 5 μm or more, or 10 μm or more. The length L1 of the first island portion 33 along the first direction D1 may be 500 μm or less, or 100 μm or less. The length L2 of the first island portion 33 along the second direction D2 may be 5 μm or more, or 10 μm or more. The length L2 of the first island portion 33 along the second direction D2 may be 500 μm or less, or 100 μm or less.

[0042] The second metal layer 30 also has a pair of first peripheral portions 34. The first peripheral portions 34 are provided at positions corresponding to the non-bending regions NA. The first pattern shape portion 32 is located between the pair of first peripheral portions 34. No opening is provided in the first peripheral portion 34, but an opening may be present in the first peripheral portion 34.

[0043] The second metal layer 30 is made of metal. The second metal layer 30 includes a main metal material. The main metal material of the second metal layer 30 is different from the main metal material of the first metal layer 20. The main metal material of the second metal layer 30 may be, for example, copper (Cu) or nickel (Ni), or an alloy thereof. When copper is used as the main metal material of the second metal layer 30, the workability of the second metal layer 30 is good, so that fine processing is possible. In addition, the thermal conductivity of the second metal layer 30 can be improved. When nickel is used as the main metal material of the second metal layer 30, the surface hardness of the second metal layer 30 is high, so that the flexible display device 70 can withstand impacts when it is in use.

[0044] The third metal layer 40 is laminated on the first surface 20a of the first metal layer 20. The third metal layer 40 is bonded to the first metal layer 20. The third metal layer 40 may be laminated on the first metal layer 20 by rolling bonding, diffusion bonding, or depositing metal by plating, as described below. The third metal layer 40 increases the strength of the metal support 10. The third metal layer 40 is provided at least in the curved region BA of the first metal layer 20. The third metal layer 40 may be provided on the entire first surface 20a of the first metal layer 20 including the curved region BA, or may be provided on a part of the first surface 20a of the first metal layer 20. The third metal layer 40 may be directly laminated on the first surface 20a of the first metal layer 20, or may be laminated on the first metal layer 20 via another layer. The thickness T3 of the third metal layer 40 may be 100 μm or less, or 50 μm or less. The thickness T3 of the third metal layer 40 may be thinner than the thickness T1 of the first metal layer 20. The thickness T3 of the third metal layer 40 may be the same as the thickness T2 of the second metal layer 30. Alternatively, the thickness T3 of the third metal layer 40 may be different from the thickness T2 of the second metal layer 30.

[0045] The third metal layer 40 has a second opening 41 that opens toward the opposite side of the first metal layer 20. In this case, the second opening 41 is a through opening that penetrates the third metal layer 40 in the thickness direction. That is, a part of the first surface 20a of the first metal layer 20 is exposed to the outside through the second opening 41. The second opening 41 may be a non-through opening that does not penetrate the third metal layer 40 in the thickness direction as long as it is opened toward the opposite side of the first metal layer 20. As shown in FIG. 5, the outer periphery of the second opening 41 does not necessarily have to be formed in a ring shape. That is, the second opening 41 may reach the outer edge of the third metal layer 40. In the example shown in FIG. 5 and FIG. 6, the second opening 41 has the same planar shape as the first opening 31. That is, the entire first opening 31 and the entire second opening 41 overlap in a planar view. However, this is not limited to this, and at least a part of the first opening 31 and at least a part of the second opening 41 may overlap in a planar view.

[0046] The third metal layer 40 has a second pattern shape portion 42 around the second opening 41. The second pattern shape portion 42 is provided at a position corresponding to the bending region BA. The second pattern shape portion 42 includes a second island portion 43 that is a portion formed in an island shape. The second pattern shape portion 42 has a second opening 41 and a plurality of second island portions 43 each having an annular periphery. A second opening 41 is formed around the second island portion 43. The second opening 41 surrounds the entire periphery of each second island portion 43. The second island portions 43 are arranged at intervals in each of the first direction D1 and the second direction D2. In the example shown in FIG. 5 and FIG. 6, the plurality of second island portions 43 have the same planar shape as the plurality of first island portions 33. That is, the positions and shapes of the first opening 31 and the first island portion 33 are the same as the positions and shapes of the second opening 41 and the second island portion 43. However, the present invention is not limited to this, and the position or shape of the first opening 31 and the first island portion 33 may be different from the position or shape of the second opening 41 and the second island portion 43.

[0047] The third metal layer 40 also has a pair of second peripheral portions 44. The second peripheral portions 44 are provided at positions corresponding to the non-bending regions NA. The second pattern shape portion 42 is located between the pair of second peripheral portions 44. No opening is provided in the second peripheral portion 44, but an opening may be present in the second peripheral portion 44.

[0048] The third metal layer 40 is made of metal. The third metal layer 40 includes a main metal material. The main metal material of the third metal layer 40 is different from the main metal material of the first metal layer 20. The main metal material of the third metal layer 40 may be, for example, copper (Cu) or nickel (Ni), or an alloy thereof. When copper is used as the main metal material of the third metal layer 40, the third metal layer 40 has good workability, so that fine processing is possible. In addition, the thermal conductivity of the third metal layer 40 can be improved. When nickel is used as the main metal material of the third metal layer 40, the surface hardness of the third metal layer 40 is high, so that the flexible display device 70 can withstand impacts when it is used. The main metal material of the third metal layer 40 may be the same as the main metal material of the second metal layer 30, or may be different from the main metal material of the second metal layer 30.

[0049] 7(a)-(c) are plan views showing modified examples of the metal support 10. As shown in FIG. 7(a), the first pattern shape portion 32 may include a plurality of first island-shaped portions 33 formed in an island shape, and the plurality of first island-shaped portions 33 may be arranged alternately (staggered). In this case, the plurality of first island-shaped portions 33 include the first island-shaped portions 33 of the first row R1 arranged at intervals from each other along the second direction D2, and the first island-shaped portions 33 of the second row R2 arranged at intervals from each other along the second direction D2. The first island-shaped portions 33 of the first row R1 and the first island-shaped portions 33 of the second row R2 are arranged at intervals from each other in the second direction D2. In this case, since the plurality of first island-shaped portions 33 are arranged alternately, it is possible to suppress stress concentration at a specific location when the flexible display device 70 is folded. In the example shown in FIG. 7(a), the third metal layer 40 has the same planar shape as the second metal layer 30. However, the present invention is not limited to this, and the third metal layer 40 may have a different planar shape from the second metal layer 30.

[0050] As shown in FIG. 7(b), the first pattern shape portion 32 may include a first linear portion that is a portion formed in a line shape. The first pattern shape portion 32 has a plurality of first linear portions in an area surrounded by virtual lines in FIG. 7(b). In this case, the plurality of first linear portions are arranged at intervals from each other in the first direction D1. Each of the first linear portions extends in a line shape along the second direction D2. This increases the area that the plurality of first linear portions cover the first metal layer 20, thereby increasing the bending strength when bending the flexible display device 70. Note that each of the first linear portions may extend in a line shape along the first direction D1. Also, the second pattern shape portion 42 of the third metal layer 40 has a plurality of second linear portions 45. In the example shown in FIG. 7(b), the third metal layer 40 has the same planar shape as the second metal layer 30. Note that this is not limited to this, and the third metal layer 40 may have a planar shape different from that of the second metal layer 30.

[0051] As shown in FIG. 7(c), the first pattern shape portion 32 may include a first mesh-like portion 36 which is a portion formed in a mesh shape. In this case, the first mesh-like portion 36 may be composed of one member. The first mesh-like portion 36 includes a first direction portion 36a extending in a first direction and a second direction portion 36b extending in a second direction. A first opening 31 is formed so as to be surrounded by the first direction portion 36a and the second direction portion 36b. The first openings 31 include first openings 31 in a first row R1 arranged at intervals from each other along the second direction D2, and first openings 31 in a second row R2 arranged at intervals from each other along the second direction D2. The first openings 31 in the first row R1 and the first openings 31 in the second row R2 are arranged so as to be shifted in the second direction D2. That is, the center points of the first openings 31 are arranged in an oblique lattice pattern. In this case, the area where the second metal layer 30 covers the first metal layer 20 increases, so that the bending strength when the flexible display device 70 is folded can be increased. In addition, since the multiple first openings 31 are arranged alternately, it is possible to reduce the concentration of stress at a specific location when the flexible display device 70 is folded. The center points of the first openings 31 may be arranged in a square lattice or rectangular lattice. In addition, the second pattern shape portion 42 of the third metal layer 40 has a second mesh-like portion 46 formed in a mesh shape. In the example shown in FIG. 7(c), the third metal layer 40 has the same planar shape as the second metal layer 30. In addition, the third metal layer 40 may have a planar shape different from that of the second metal layer 30.

[0052] (Method of manufacturing a metal support for a flexible display device) Next, a method for manufacturing the metal support 10 shown in FIGS. 5 and 6 will be described with reference to FIGS. 8(a)-(d).

[0053] First, as shown in Fig. 8(a), a laminate 60 including a first metal layer 20, a second metal layer 30A, and a third metal layer 40A is prepared. The second metal layer 30A is in a state before the openings are formed, and is laminated on the second surface 20b of the first metal layer 20. Similarly, the third metal layer 40A is in a state before the openings are formed, and is laminated on the first surface 20a of the first metal layer 20.

[0054] The method of producing the laminate 60 is not limited. For example, the laminate 60 may be a clad material. In this case, the laminate 60 may be produced by rolling and bonding the first metal layer 20, the second metal layer 30A, and the third metal layer 40A under pressure. Alternatively, the laminate 60 may be produced by diffusion bonding the first metal layer 20, the second metal layer 30A, and the third metal layer 40A. Alternatively, the laminate 60 may be produced by forming the second metal layer 30A and the third metal layer 40A on the first metal layer 20 by plating, respectively.

[0055] Next, as shown in FIG. 8(b), a first protective layer 51 and a second protective layer 52 are provided on the laminate 60. Specifically, the first protective layer 51 having a first protective layer opening 51a is provided on the second metal layer 30A, and the second protective layer 52 having a second protective layer opening 52a is provided on the third metal layer 40A. The first protective layer 51 and the second protective layer 52 may each be a resist layer. At this time, a photosensitive resist is first applied to the entire second metal layer 30A and the third metal layer 40A, respectively, and dried. Then, the photosensitive resist on the second metal layer 30A and the third metal layer 40A is exposed through a photomask, respectively, and developed. As a result, the first protective layer 51 having the first protective layer opening 51a is formed on the second metal layer 30A, and the second protective layer 52 having the second protective layer opening 52a is formed on the second surface 20b. The planar shape of the first protective layer opening 51a corresponds to the planar shape of the first opening 31. The planar shape of the second protective layer opening 52a corresponds to the planar shape of the second opening 41.

[0056] Next, as shown in FIG. 8(c), the second metal layer 30A is etched with an etchant using the first protective layer 51 as a corrosion-resistant film. Similarly, the third metal layer 40A is etched with an etchant using the second protective layer 52 as a corrosion-resistant film. The etchant can be appropriately selected according to the material of the second metal layer 30A and the third metal layer 40A. For example, when copper is used as the second metal layer 30A and the third metal layer 40A, a ferric chloride aqueous solution may be used as the etchant and spray etching may be performed on the second metal layer 30A and the third metal layer 40A. As a result, a first opening 31 penetrating the second metal layer 30A is formed in the second metal layer 30A. Similarly, a second opening 41 penetrating the third metal layer 40A is formed in the third metal layer 40A. The main metal material of the first metal layer 20 is different from the main metal materials of the second metal layer 30A and the third metal layer 40A. Therefore, the first metal layer 20 is not etched.

[0057] Thereafter, as shown in Fig. 8(d), the first protective layer 51 on the second metal layer 30 and the second protective layer 52 on the third metal layer 40 are peeled off and removed, respectively. In this manner, the metal support 10 shown in Figs. 5 and 6 is obtained.

[0058] Thus, according to the present embodiment, the metal support 10 includes the first metal layer 20 and the second metal layer 30, and the second metal layer 30 has the first opening 31. This makes it possible to improve the flexibility of the bending region BA of the flexible display device 70 when the metal support 10 is incorporated into the flexible display device 70. As a result, the shape of the bending region BA can be made smaller when the flexible display device 70 is folded. In other words, the radius of curvature of the bending region BA can be made smaller.

[0059] Furthermore, according to this embodiment, the strength of the metal support 10 is increased by laminating the second metal layer 30 on the first metal layer 20. Furthermore, the heat dissipation from the second metal layer 30 is improved.

[0060] Furthermore, according to this embodiment, the third metal layer 40 is laminated on the first surface 20a of the first metal layer 20. In this manner, by evenly sandwiching the first metal layer 20 between the second metal layer 30 and the third metal layer 40, it is possible to prevent warping of the metal support 10 before it is incorporated into the flexible display device 70. Note that the metal support 10 may be composed of four or more metal layers.

[0061] Furthermore, according to the present embodiment, the third metal layer 40 has the second opening 41. This makes it possible to improve the flexibility of the bending region BA of the flexible display device 70 when the metal support 10 is incorporated into the flexible display device 70.

[0062] Furthermore, according to this embodiment, the second metal layer 30 has portions formed in an island, line, or mesh shape. In this case, spaces (first openings 31) are formed between the first island portions 33, between the first line portions, or inside the first mesh portions 36. This makes it possible to suppress a decrease in the flexibility of the metal support 10 in the bending region BA, compared to a case in which the entire bending region BA of the metal support 10 is covered with metal.

[0063] (Modification) Next, modified examples of the metal support 10 will be described with reference to Fig. 9(a)-(d). Fig. 9(a)-(d) are cross-sectional views showing modified examples of the metal support 10. In Fig. 9(a)-(d), the same parts as those shown in Fig. 1 to Fig. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0064] As shown in FIG. 9(a), the first opening 31 of the second metal layer 30 and the second opening 41 of the third metal layer 40 may be formed to be offset from each other in a plan view. In this case, the first opening 31 and the second opening 41 are arranged so as not to overlap each other in a plan view. The overlap width δa between the metal part of the first pattern shape portion 32 and the metal part of the second pattern shape portion 42 may be 1 μm or more and 50 μm or less. In this way, the first opening 31 and the second opening 41 are formed to be offset from each other in a plan view, so that there is no part of the first metal layer 20 that is not covered by both the second metal layer 30 and the third metal layer 40. Therefore, when the flexible display device 70 is folded, it is possible to suppress stress concentration at a specific part of the first metal layer 20.

[0065] As shown in FIG. 9(b), the first opening 31 of the second metal layer 30 and the second opening 41 of the third metal layer 40 may be formed to be offset from each other in a plan view. In this case, a part of the first opening 31 and a part of the second opening 41 are arranged to overlap each other in a plan view. The overlap width δb between the first opening 31 and the second opening 41 may be 1 μm or more and 50 μm or less. This makes it possible to enhance the flexibility of the metal support 10 in the bending region BA while suppressing stress concentration at a specific point of the first metal layer 20 when the flexible display device 70 is bent.

[0066] As shown in Fig. 9(c), the third metal layer 40 may not have the second opening 41. The third metal layer 40 spreads without gaps over at least the entire curved region BA. The third metal layer 40 may spread without gaps over the entire first surface 20a. Since the third metal layer 40 does not have an opening, the third metal layer 40 side of the metal support 10 can be flattened, and the display member 71 can be attached to the flatter surface of the metal support 10.

[0067] When producing the metal support 10 shown in Fig. 9(c), in the step of providing the first protective layer 51 and the second protective layer 52 on the above-mentioned laminate 60 (see Fig. 8(b)), the second protective layer 52 used does not have an opening (second protective layer opening 52a). This makes it possible to prevent an opening from being formed in the third metal layer 40A during the above-mentioned etching (see Fig. 8(c)).

[0068] As shown in FIG. 9(d), the metal support 10 may not have the third metal layer 40. In this case, the metal support 10 includes the first metal layer 20 and the second metal layer 30. That is, the metal support 10 is made of a two-layer laminate. The first surface 20a of the first metal layer 20 is exposed to the outside over its entirety. Since the metal support 10 does not have the third metal layer 40, the first surface 20a side of the metal support 10 can be flattened, and the display member 71 can be attached to the flatter surface of the metal support 10. Furthermore, the metal support 10 can be made thin.

[0069] When producing the metal support 10 shown in FIG. 9(d), in the step of providing the first protective layer 51 and the second protective layer 52 on the laminate 60 described above (see FIG. 8(b)), the second protective layer 52 is not provided on the third metal layer 40A. As a result, the third metal layer 40A is entirely etched away during the above-mentioned etching (see FIG. 8(c)). Alternatively, a two-layer laminate consisting of the first metal layer 20 and the second metal layer 30A may be used as the laminate 60 described above (see FIG. 8(a)). As a result, a two-layer metal support 10 including the first metal layer 20 and the second metal layer 30 is obtained.

[0070] It is also possible to combine the multiple components disclosed in the above embodiments and modifications as necessary. Alternatively, some components may be deleted from all the components shown in the above embodiments and modifications. [Explanation of symbols]

[0071] 10 Metallic support for flexible display devices 20 1st metal layer 20a Page 1 20b 2nd side 30 Second metal layer 31 First opening 32 First pattern shape portion 33 1st island part 34 First Periphery 40 Third metal layer 41 Second opening 42 Second pattern shape portion 43 Second island-shaped part 44 Second Periphery 70 Flexible display device

Claims

1. In a metal support for a flexible display device, a first metal layer having a first surface and a second surface; a second metal layer laminated on the second surface of the first metal layer, a main metal material constituting the first metal layer and a main metal material constituting the second metal layer are different from each other; the second metal layer has a first opening; the metal support has a curved region and a non-bent region, and the first opening is provided at a position corresponding to the curved region; The metal support for a flexible display device, wherein the first metal layer has no openings.

2. A metal support for a flexible display device, a first metal layer having a first surface and a second surface; a second metal layer laminated on the second surface of the first metal layer, a main metal material constituting the first metal layer and a main metal material constituting the second metal layer are different from each other; the second metal layer has a first opening; the metal support has a curved region and a non-bent region, and the first opening is provided at a position corresponding to the curved region; The first opening penetrates the second metal layer in the thickness direction, and a portion of the second surface of the first metal layer is exposed to the outside through the first opening.

3. The metal support for a flexible display device according to claim 1 or 2, further comprising a third metal layer laminated on the first surface of the first metal layer.

4. The metal support for a flexible display device according to claim 3 , wherein the third metal layer has a second opening.

5. The metal support for a flexible display device according to claim 4 , wherein at least a portion of the first opening of the second metal layer and at least a portion of the second opening of the third metal layer overlap in a plan view.

6. The metal support for a flexible display device according to claim 4 , wherein at least a part of the first opening of the second metal layer and at least a part of the second opening of the third metal layer are misaligned in a plan view.

7. The metal support for a flexible display device according to claim 4 , wherein the third metal layer has no opening.

8. 3. The metal support for a flexible display device according to claim 1, wherein the second metal layer has a patterned portion around the first opening, and the patterned portion includes a portion formed in an island shape, a line shape, or a mesh shape.

9. A display member; A flexible display device comprising: the metal support for a flexible display device according to claim 1 or 2, which supports the display member.

10. A method for producing a metal support for a flexible display device, comprising: preparing a laminate including a first metal layer having a first surface and a second surface, and a second metal layer laminated on the second surface of the first metal layer, wherein a primary metal material constituting the first metal layer and a primary metal material constituting the second metal layer are different from each other; providing a second protective layer having a second protective layer opening on the second metal layer of the stack; and forming a first opening in the second metal layer by etching the second metal layer of the laminate; The method for manufacturing a metal support for a flexible display device, wherein the first metal layer is not etched.

11. A method for manufacturing a metal support for a flexible display device, comprising: preparing a laminate including a first metal layer having a first surface and a second surface, and a second metal layer laminated on the second surface of the first metal layer, wherein a primary metal material constituting the first metal layer and a primary metal material constituting the second metal layer are different from each other; providing a second protective layer having a second protective layer opening on the second metal layer of the stack; and forming a first opening in the second metal layer by etching the second metal layer of the laminate; A method for manufacturing a metal support for a flexible display device, comprising forming the first opening in the second metal layer, thereby exposing a portion of the second surface of the first metal layer to the outside through the first opening.

12. the stack further includes a third metal layer stacked on the first surface of the first metal layer; The method for producing a metal support for a flexible display device includes: The method for manufacturing a metal support for a flexible display device according to claim 10 or 11, further comprising the step of providing a first protective layer on the third metal layer.

13. the first protective layer has a first protective layer opening; The method for manufacturing a metal support for a flexible display device according to claim 12 , wherein a second opening is formed in the third metal layer in the etching step.

14. the first protective layer does not have an opening; The method for manufacturing a metal support for a flexible display device according to claim 12 , wherein no opening is formed in the third metal layer in the etching step.

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