Display device and method of manufacturing the same

Abstract

A display device and a method for manufacturing the display device are provided. The display device has a first non-foldable area, a second non-foldable area spaced apart from the first non-foldable area, and a foldable area arranged between the first non-foldable area and the second non-foldable area. The display device includes a supporting member, a first adhesive layer arranged on the supporting member, a buffer member arranged on the first adhesive layer, a second adhesive layer arranged on the buffer member, and a flexible display panel arranged on the second adhesive layer. At least one of the supporting member and the buffer member includes a first area overlapping with a foldable area having at least one first concavo-convex body for facilitating bending, and the at least one first concavo-convex body is formed on the surface of the first area.

Description

Technical Field

[0001] Exemplary implementations of the present invention generally relate to a display device and a method of manufacturing the display device, and more particularly, to a foldable display device and a method of manufacturing the foldable display device. Background Art

[0002] Recently, with the improvement of technology, display products with smaller size, lighter weight and better performance are being produced. Conventional cathode ray tube (CRT) televisions have been widely used as display devices because of their many advantages in performance and price. However, recently, display devices (such as plasma display devices, liquid crystal display devices and organic light emitting display devices) have gained much attention because they overcome the weaknesses of CRT in miniaturization or portability and have advantages such as miniaturization, light weight, low power consumption, etc.

[0003] Recently, various types of display devices other than flat display devices have been developed. For example, various flexible display devices such as curved display devices, bendable display devices, foldable display devices, rollable display devices, and stretchable display devices have been developed. In particular, a foldable display device that can be folded bidirectionally around a foldable axis has been developed.

[0004] The above information disclosed in this Background section is only for understanding the background of the present invention concept and therefore it may contain information that does not constitute the prior art. Summary of the invention

[0005] The applicant has realized that, for a foldable display device, stress in the foldable region may be higher than stress in the non-foldable region, and thus defects such as delamination of the layer structure, bubbles, etc. may occur in the foldable region of the foldable display device.

[0006] The display device constructed according to the concepts and exemplary implementations of the present invention and the exemplary method of manufacturing the display device according to the concepts of the present invention prevent or at least reduce defects caused by repeated folding and unfolding of the display device. For example, the display device may include at least one area having at least one concave-convex body to facilitate folding, and thereby prevent or at least reduce defects in the foldable area and / or the non-foldable area adjacent to the foldable area.

[0007] Additional features of the inventive concept will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concept.

[0008] According to one aspect of the present invention, a display device having a first non-foldable area, a second non-foldable area spaced apart from the first non-foldable area, and a foldable area arranged between the first non-foldable area and the second non-foldable area is provided, the display device comprising a supporting member, a first adhesive layer arranged on the supporting member, a buffer member arranged on the first adhesive layer, a second adhesive layer arranged on the buffer member, and a flexible display panel arranged on the second adhesive layer. At least one of the supporting member and the buffer member comprises a first area overlapping with the foldable area having at least one first concavo-convex body for facilitating bending, and the at least one first concavo-convex body is formed on the surface of the first area.

[0009] The support member may include a lower plate including a first metal layer, a film layer disposed on the first metal layer and including the first region, and a second metal layer disposed on the film layer.

[0010] The buffer member may include a buffer plate, the buffer plate including a second area overlapping the foldable area, the second area having at least one second concave-convex body for easy bending. The first area may have a first width. The second area may have a second width greater than the first width.

[0011] The first and second regions may include first and second corrugated regions having corrugations formed on surfaces of the film layer and the buffer sheet, respectively, and the second region of the buffer sheet may partially overlap the first and second non-foldable regions.

[0012] The lower plate may further include a lower adhesive layer disposed between the first metal layer and the film layer, and an upper adhesive layer disposed between the film layer and the second metal layer.

[0013] The support member may include a film layer including the first region, and the film layer of the support member may include a resin layer having thermally conductive balls.

[0014] The first region may include a corrugated region having corrugations formed on top and bottom surfaces thereof.

[0015] The first adhesive layer and the second adhesive layer may include a third region and a fourth region overlapping the foldable region, and at least one of the third region and the fourth region has at least one concavo-convex body to facilitate folding.

[0016] The first region may include fine particles comprising calcium carbonate.

[0017] According to another aspect of the present invention, a method for manufacturing a display device includes the following steps: forming a film layer by using a resin solution containing a plurality of fine particles having alkalinity; performing acid treatment by allowing an acidic solution to contact the film layer to remove some of the plurality of fine particles adjacent to the surface of the film layer; forming wrinkles on the surface of the film layer by curing the acid-treated film layer; and attaching a display panel to the film layer having the wrinkles.

[0018] The plurality of fine particles may include calcium carbonate (CaCO 3 ).

[0019] Surfaces of the plurality of fine particles may be hydrophobically treated.

[0020] The hydrophobic treatment can be achieved by adding a mixture containing calcium carbonate (CaCO 3 ) is mixed with ethanol and stearic acid.

[0021] The acidic solution may include dilute hydrochloric acid.

[0022] When the acid-treated film layer is cured, the film layer may be thermally cured at a temperature greater than about 100°C.

[0023] The plurality of fine particles may have an average size of less than about 0.1 μm.

[0024] The method may further include the step of attaching a metal plate to the film layer before attaching the display panel to the film layer.

[0025] The method may further include the step of attaching a buffer plate to the metal plate before attaching the display panel to the film layer.

[0026] The film layer may include a corrugated region having corrugations and a plurality of flat regions spaced apart from each other, and the corrugated region may be formed between the plurality of flat regions.

[0027] According to another aspect of the present invention, a display device includes a flexible display panel having a foldable region and a film layer arranged below the flexible display panel. The film layer includes fine particles containing calcium carbonate overlapping the foldable region.

[0028] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the inventive concept.

[0030] Figure 1is a perspective view of an exemplary embodiment of a display device constructed according to the concepts of the present invention.

[0031] Figure 2 It is in folded state Figure 1 A perspective view of a display device.

[0032] Figure 3 yes Figure 2 A cross-sectional view of an exemplary embodiment of a foldable area and an adjacent non-foldable area in a display device.

[0033] Figure 4 It is in the expanded state Figure 3 A cross-sectional view of a foldable area and an adjacent non-foldable area in a display device.

[0034] Figure 5A yes Figure 4 FIG. 5 is a cross-sectional view of an exemplary embodiment of a first adhesive layer.

[0035] Figure 5B yes Figure 4 A cross-sectional view of an exemplary embodiment of a buffer plate.

[0036] Figure 5C yes Figure 4 A cross-sectional view of an exemplary embodiment of a lower plate.

[0037] Fig. 6A yes Figure 4 FIG. 5 is a cross-sectional view of another exemplary embodiment of a first adhesive layer.

[0038] Figure 6B yes Figure 4 A cross-sectional view of another exemplary embodiment of a lower plate of FIG.

[0039] Figure 7 is a flowchart of a method of manufacturing an adhesive layer for a display device according to the concept of the present invention.

[0040] Figure 8 is a flowchart of a method of manufacturing a lower plate for a display device according to the concept of the present invention.

[0041] Fig. 9 is a flowchart of a method of manufacturing a display device according to the concept of the present invention.

[0042] Fig. 10A and Fig. 10B is a diagram showing an example of the surface of a wrinkle region of a display device manufactured according to the concept of the present invention.

[0043] Fig.11 is a block diagram of an exemplary embodiment of an electronic device including a display device constructed according to the concepts of the present invention. DETAILED DESCRIPTION

[0044] In the following description, for the purpose of explanation, many specific details are set forth to provide a thorough understanding of various exemplary embodiments or implementations of the present invention. As used herein, "implementation" and "implementation" are interchangeable words, which are non-limiting examples of devices or methods using one or more of the inventive concepts disclosed herein. However, it is apparent that various exemplary embodiments can be practiced without specific details or in the case of one or more equivalent arrangements. In other examples, known structures and devices are shown in block diagram form to avoid unnecessary confusion of various exemplary embodiments. In addition, various exemplary embodiments may be different, but need not be exclusive. For example, without departing from the inventive concept, the specific shape, configuration and characteristics of the exemplary embodiment may be used or implemented in another exemplary embodiment.

[0045] Unless otherwise specified, the exemplary embodiments shown will be understood as providing exemplary features of various details of some ways in which the inventive concept can be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions and / or aspects, etc. (hereinafter individually or collectively referred to as "elements") of various embodiments may be combined, separated, interchanged and / or rearranged in other ways without departing from the inventive concept.

[0046] The use of cross hatching and / or shading in the drawings is generally provided to clarify the boundaries between adjacent elements. As such, unless otherwise stated, whether cross hatching or shading exists or not, it will not convey or indicate any preference or requirement for a specific material, material property, size, ratio, commonality between the elements shown and / or any other characteristics, attributes, properties, etc. of the elements. In addition, in the drawings, the size and relative size of the elements may be exaggerated for the purpose of clarity and / or description. When the exemplary embodiments can be implemented in different ways, the specific process sequence can be performed differently from the described sequence. For example, two processes described in succession can be performed substantially simultaneously or in an order opposite to the described order. In addition, similar reference numerals represent similar elements.

[0047] When an element (such as a layer) is referred to as being "on" another element or layer, or being "connected to" or "coupled to" another element or layer, the element (e.g., layer) may be directly on another element or layer, or connected to or coupled to another element or layer, or there may be an intermediate element or layer. However, when an element or layer is referred to as being "directly" "on" another element or layer, or being "directly connected to" or "directly coupled to" another element or layer, there is no intermediate element or layer. For this reason, the term "connection" may refer to a physical, electrical and / or fluid connection with or without an intermediate element. In addition, the D1-axis, D2-axis, and D3-axis are not limited to the three axes of a rectangular coordinate system (such as an x-axis, a y-axis, and a z-axis), and may be interpreted in a broader sense. For example, the D1-axis, the D2-axis, and the D3-axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purpose of this disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" may be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as, for example, XYZ, XYY, YZ, and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0048] Although the terms "first", "second", etc. may be used herein to describe various types of elements, these components should not be limited by these terms. These terms are used to distinguish one element from another element. Therefore, without departing from the teachings of the present disclosure, the first element discussed below may be referred to as the second element.

[0049] Spatially relative terms such as "below," "beneath," "below," "above," "on," "over," "higher," "side" (e.g., as in "sidewall") and the like may be used herein for descriptive purposes and thereby to describe the relationship of one element to another element as shown in the figures. In addition to the orientations depicted in the figures, spatially relative terms are also intended to cover different orientations of the device in use, operation, and / or manufacture. For example, if the device in the figure is flipped, an element described as being "below" or "beneath" other elements or features will subsequently be oriented to be "above" the other elements or features. Thus, the exemplary term "below" may include both an orientation above and an orientation below. In addition, the device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and, as such, the spatially relative descriptors used herein are interpreted accordingly.

[0050] The terms used herein are for the purpose of describing specific embodiments and are not intended to be limiting. Unless the context clearly states otherwise, the singular forms "one" and "the" as used herein are also intended to include plural forms. In addition, the term "including", when used in this specification, illustrates the existence of stated features, integers, steps, operations, elements, parts and / or its clusters, but does not exclude the existence or addition of one or more other features, integers, steps, operations, elements, parts and / or its clusters. It is also noted that, as used herein, the terms "substantially", "about" and other similar terms are used as approximate terms rather than terms of degree, and, as such, they are utilized to explain the inherent deviations of measured values, calculated values ​​and / or provided values ​​that will be recognized by those of ordinary skill in the art.

[0051] Various exemplary embodiments are described herein with reference to cross-sections and / or exploded illustrations, which are schematic illustrations of idealized exemplary embodiments and / or intermediate structures. As such, variations in the shapes of the illustrations as a result of, for example, manufacturing techniques and / or tolerances are to be expected. Thus, the exemplary embodiments disclosed herein should not necessarily be construed as limited to the specific illustrated shapes of regions, but rather are to include deviations in shapes resulting from, for example, manufacturing. In this manner, the regions illustrated in the figures may be schematic in nature, and the shapes of these regions may not reflect the actual shapes of the regions of the device, and, as such, are not necessarily intended to be limiting.

[0052] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. Unless explicitly defined as such herein, terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and should not be interpreted in an idealized or overly formal sense.

[0053] Figure 1 is a perspective view of an exemplary embodiment of a display device 10 constructed according to the concepts of the present invention. Figure 2 It is in folded state Figure 1 1 is a perspective view of a display device 10 .

[0054] Reference Figure 1 and Figure 2, a foldable display is shown as an example of the display device 10. However, the exemplary embodiment is not limited thereto. For example, the display device 10 may be applied to various display devices such as a curved display device, a bendable display device, a rollable display device, and a stretchable display device. In addition, in addition to a television or a large electronic device such as an external billboard, the display device 10 may be used in small and medium-sized electronic devices such as mobile phones, personal computers, notebook computers, personal digital terminals, car navigation units, game consoles, portable electronic devices, watch-type electronic devices, and cameras.

[0055] The display device 10 may include a plurality of areas defined on a display surface. The display device 10 may include a display area DA and a non-display area NDA. The display area DA may be an area for displaying an image. The non-display area NDA may be an area adjacent to the display area DA. The non-display area NDA does not display an image. In an embodiment, the display area DA may have a substantially rectangular shape. The non-display area NDA may be adjacent to the display area DA and may surround the display area DA. In addition, the non-display area NDA may be omitted.

[0056] The display area DA of the display device 10 may be arranged substantially parallel to a surface defined by a first direction D1 and a second direction D2 perpendicular to the first direction D1. A normal direction of the surface of the display device 10 is indicated by a third direction D3. The third direction D3 indicates a thickness direction of the display device 10.

[0057] The display device 10 may include a foldable area FA that can be folded around a foldable axis FX according to an action and one or more adjacent non-foldable areas, such as a first non-foldable area NFA1 and a second non-foldable area NFA2 that cannot be folded. The foldable axis FX may be in the same direction as the second direction D2. The first non-foldable area NFA1 and the second non-foldable area NFA2 may be arranged with the foldable area FA interposed therebetween. In other words, the first non-foldable area NFA1 may extend from one end of the foldable area FA in the first direction D1, and the second non-foldable area NFA2 may extend from the other end of the foldable area FA.

[0058] The foldable area FA may be folded about the foldable axis FX so that the display surface of the first non-foldable area NFA1 and the display surface of the second non-foldable area NFA2 face each other. In this case, the lower surface of the display device 10 may face upward.

[0059] As described above, the display device 10 can be folded inwardly about the foldable axis FX so that the display surface of the first non-foldable area NFA1 and the display surface of the second non-foldable area NFA2 can face each other, which is defined as an inner fold. The display device 10 can also be folded outwardly about the foldable axis FX so that the display surface of the first non-foldable area NFA1 and the display surface of the second non-foldable area NFA2 can face opposite directions, which is defined as an outer fold.

[0060] Figure 3 yes Figure 2 1 is a cross-sectional view of an exemplary embodiment of a foldable area FA and adjacent non-foldable areas NFA1 and NFA2 in a display device 10. Figure 4 It is in the expanded state Figure 3 1 is a cross-sectional view of a foldable area FA and adjacent non-foldable areas NFA1 and NFA2 in a display device 10. Figure 5A yes Figure 4 sectional view of an exemplary embodiment of a first adhesive layer PSA1. Figure 5B yes Figure 4 sectional view of an exemplary embodiment of a buffer panel CP. Figure 5C yes Figure 4 A cross-sectional view of an exemplary embodiment of a lower plate LPT.

[0061] Reference Figures 3 to 5C The display device 10 may include a support member which may be in the form of a lower panel LPT, a first adhesive layer PSA1, a buffer member which may be in the form of a buffer panel CP, a second adhesive layer PSA2, a display panel DP, a third adhesive layer PSA3, and a cover window CW.

[0062] The lower plate LPT may be substantially rigid to support components of the display device 10, and may be configured to dissipate heat generated from some of the various components of the display device, such as the display panel DP. Figure 5C As shown in , the lower plate LPT may include a first metal layer MP1, a lower adhesive layer AD1, a film layer CF, an upper adhesive layer AD2, and a second metal layer MP2.

[0063] The first metal layer MP1 may be a metal plate. The metal plate may include a high modulus material. For example, the first metal layer MP1 may include at least one selected from the group consisting of Invar, Nobinite, stainless steel, and alloys thereof, but is not limited thereto.

[0064] The lower adhesive layer AD1 may be disposed on the first metal layer MP1. The first metal layer MP1 and the film layer CF may be attached to each other through the lower adhesive layer AD1. The lower adhesive layer AD1 may include a pressure sensitive adhesive (PSA) as a main component. The pressure sensitive adhesive may be at least one selected from the group consisting of acrylic, silicone, polyester, rubber, and polyurethane polymers, but is not limited thereto.

[0065] In an exemplary embodiment, the pressure-sensitive adhesive may include an acrylic copolymer formed by copolymerizing an acrylic compound with other monomers. The acrylic compound may include an acrylic monomer having 1 to 18 carbons, and more specifically, may include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, and the like, but are not limited thereto. Other monomers copolymerized with the acrylic compound may include styrene-based monomers, olefin-based monomers, vinyl esters, cyano-containing monomers, amide-containing monomers, hydroxyl-containing monomers, acidic-containing monomers, epoxy-containing monomers, amino-containing monomers, carboxyl-containing monomers, and the like, but are not limited thereto.

[0066] The film layer CF may be arranged on the lower adhesive layer AD1. The film layer CF may include an area including at least one concavoconvex body for folding, such as a wrinkle area WA, and in the wrinkle area WA, wrinkles WC are formed on the surface of the film layer CF. The wrinkle area WA of the film layer CF may be formed to have a first width W1 substantially equal to the width of the foldable area FA. The wrinkles WC may be formed on both the top surface and the bottom surface of the film layer CF. For example, the wrinkles WC may be formed in an undulating concavoconvex shape on the surface.

[0067] The film layer CF may have thermal conductivity. When the film layer CF has thermal conductivity, a favorable heat dissipation structure may be realized in which the heat generated by the display panel DP is discharged and / or dissipated to the outside. For example, the film layer CF may be formed of a resin layer including thermally conductive balls. In some exemplary embodiments, the film layer CF may be formed of an insulating layer that does not have thermal conductivity.

[0068] The upper adhesive layer AD2 may be arranged on the film layer CF. The second metal layer MP2 and the film layer CF may be attached to each other through the upper adhesive layer AD2. The upper adhesive layer AD2 may include a pressure sensitive adhesive (PSA) as a main component. The pressure sensitive adhesive may be at least one selected from the group consisting of acrylic, silicone, polyester, rubber, and polyurethane polymers, but is not limited thereto.

[0069] The second metal layer MP2 may be disposed on the upper adhesive layer AD2. The second metal layer MP2 may be a metal plate. The metal plate may include a high modulus material. For example, the second metal layer MP2 includes at least one selected from the group consisting of Invar, Nobinite, stainless steel, and alloys thereof, but is not limited thereto.

[0070] The wrinkles WC of the wrinkle area WA of the film layer CF can allow the film layer CF to have a high strain rate. Accordingly, when the foldable area FA of the lower panel LPT is bent and / or folded, the shear stress at the interlayer interface can be reduced, and adhesive delamination, wrinkle deformation, bubble generation, or the like caused by repulsive force due to the difference in curvature of the interlayer interface can be prevented or at least reduced.

[0071] Other layers arranged below the display panel DP may also include regions having uneven bodies, such as wrinkle regions. The first adhesive layer PSA1 may be arranged on the lower plate LPT. The first adhesive layer PSA1 may include a pressure-sensitive adhesive (PSA) as a main component. The pressure-sensitive adhesive may be at least one selected from the group consisting of acrylic, silicone, polyester, rubber, and polyurethane polymers, but is not limited thereto.

[0072] like Figure 5A As shown in FIG. 1 , the first adhesive layer PSA1 may include a wrinkle area WA formed on the surface of the first adhesive layer PSA1 with wrinkles WC. Figure 4 As shown in , the wrinkles WC of the first adhesive layer PSA1 may be formed to have a second width W2 greater than the first width W1. A portion of the wrinkle area WA of the first adhesive layer PSA1 may overlap the first non-foldable area NFA1 and the second non-foldable area NFA2. For its part, the wrinkle area WA of the first adhesive layer PSA1 may overlap the foldable area FA and the first non-foldable area NFA1 and the second non-foldable area NFA2.

[0073] The buffer plate CP may be disposed on the first adhesive layer PSA1. The buffer plate CP may be disposed between the lower plate LPT and the display panel DP and may be used to protect the display panel DP from external impact. The buffer plate CP may be formed of a material having excellent compressive stress and having excellent impact and vibration absorption. For example, the buffer plate CP may be formed of acrylic resin, polyurethane, or latex, but is not limited thereto.

[0074] like Figure 5B As shown in , the buffer panel CP may include a wrinkle area WA formed on the surface of the buffer panel CP with wrinkles WC. The wrinkles WC of the buffer panel CP may be formed to have a second width W2. A portion of the wrinkle area WA of the buffer panel CP may overlap with the first non-foldable area NFA1 and the second non-foldable area NFA2. As such, the wrinkle area WA of the buffer panel CP may overlap with the foldable area FA and the first non-foldable area NFA1 and the second non-foldable area NFA2.

[0075] The second adhesive layer PSA2 may be disposed on the buffer plate CP. The second adhesive layer PSA2 may include a pressure-sensitive adhesive (PSA) as a main component. The pressure-sensitive adhesive may be at least one selected from the group consisting of acrylic, silicone, polyester, rubber, and polyurethane polymers, but is not limited thereto.

[0076] The second adhesive layer PSA2 may be configured in substantially the same manner as the first adhesive layer PSA1. The second adhesive layer PSA2 may include a wrinkle region on the surface of the wrinkle region such that wrinkles are formed. The wrinkle region of the second adhesive layer PSA2 may be formed to have a second width W2 greater than the first width W1. A portion of the wrinkle region of the second adhesive layer PSA2 may overlap the first non-foldable area NFA1 and the second non-foldable area NFA2.

[0077] exist Figure 3 and Figure 4 , the shaded portion may be a wrinkle area where wrinkles may be formed on at least one surface of each layer.

[0078] The display panel DP may be a flexible display panel. The display panel DP may include a foldable area vertically overlapping with the foldable area FA of the display device 10. For example, the display panel DP includes a plurality of non-foldable areas and a foldable area arranged between the plurality of non-foldable areas, and the plurality of non-foldable areas and the foldable area correspond to the first non-foldable area NFA1 and the second non-foldable area NFA2 and the foldable area FA, respectively. The display panel DP may be a flexible organic light-emitting display device including a base layer, a display element arranged on the base layer, and an encapsulation layer arranged on the display element. The display element may include a first electrode, a light-emitting layer, and a second electrode.

[0079] The third adhesive layer PSA3 may be disposed on the display panel DP. The third adhesive layer PSA3 may include a pressure sensitive adhesive (PSA) as a main component. The pressure sensitive adhesive may be at least one selected from the group consisting of acrylic, silicone, polyester, rubber, and polyurethane polymers, but is not limited thereto.

[0080] The cover window CW may be disposed on the third adhesive layer PSA 3. The cover window CW may be formed of a transparent hard material so that the display panel DP may be protected from external impact while allowing an image of the display panel DP to pass therethrough without any change.

[0081] According to the conventional foldable display device, since the metal plate cannot be easily folded, the metal plate is separately arranged to be placed only in the non-foldable area, not in the foldable area. Accordingly, defects such as wrinkles and bubbles and appearance defects (e.g., corrugations) may be caused in the folding area.

[0082] In an exemplary embodiment, the foldable display device 10 includes a layer including a wrinkle area, and the wrinkle area has a wrinkle surface, so that defects can be prevented or at least reduced. For example, the lower panel LPT includes a first metal layer MP1 and a second metal layer MP2 arranged in the foldable area FA and the first non-foldable area NFA1 and the second non-foldable area NFA2 to prevent defects. The lower panel LPT may also include a film layer CF including a wrinkle area. The film layer CF including the wrinkle area has a relatively high strain rate, and the relatively high strain rate can reduce the shear stress at the interlayer interface of the multiple layers of the lower panel LPT and / or the display device 10, and when the display device 10 is folded, the relatively high strain rate can prevent or at least reduce the adhesive delamination, wrinkle deformation, bubble generation, or the like caused by the repulsive force due to the difference in curvature of the interlayer interface. Therefore, the lower panel LPT and / or the display device 10 are easy to fold and unfold without causing defects such as wrinkles and bubbles and appearance defects. In addition, the first adhesive layer PSA1 and the second adhesive layer PSA2 and the buffer plate CP may include a wrinkle area with a relatively high strain rate, and these may also facilitate the folding and unfolding of the lower plate LPT and / or the display device 10 without causing such defects. The display device 10 can be provided by applying a manufacturing method using a hydrogel. An exemplary method of manufacturing the display device 10 will be described later.

[0083] A touch sensor configured to detect a user's touch action may be further disposed between the display panel DP and the cover window CW. The touch sensor may be implemented on a separate substrate so as to be disposed on the display panel DP, or may be directly implemented inside the display panel DP.

[0084] Fig. 6A yes Figure 4 FIG. 5 is a cross-sectional view of another exemplary embodiment of a first adhesive layer PSA1 . Figure 6B yes Figure 4 sectional view of another exemplary embodiment of a lower plate LPT.

[0085] Reference Fig. 6A and Figure 6B, except for the wrinkle area WA formed by the wrinkles WC of each layer, the first adhesive layer PSA1' and the lower plate LPT' are Figure 5A and Figure 5C The first adhesive layer PSA1 and the lower plate LPT are substantially the same. Therefore, for the sake of brevity, repeated descriptions thereof will be omitted.

[0086] exist Fig. 6A , the first adhesive layer PSA1' may have wrinkles WC only in the wrinkle area WA on the bottom surface of the first adhesive layer PSA1'. The second adhesive layer PSA2, the buffer plate CP and / or other layers arranged below the display panel DP may also have wrinkles only on one side thereof. In addition, although the figure shows that the wrinkles WC are formed on the bottom surface of the first adhesive layer PSA1', the wrinkles may be formed only on the top surface.

[0087] exist Figure 6B , the film layer CF of the lower plate LPT' may have the wrinkles WC only in the wrinkle area WA on the bottom surface of the film layer CF. Although the figure shows that the wrinkles WC are formed on the bottom surface of the film layer CF, the wrinkles may be formed only on the top surface.

[0088] Figure 7 is a flowchart of a method of manufacturing an adhesive layer for a display device according to the concept of the present invention.

[0089] Reference Figure 7 , a method of manufacturing an adhesive layer for a display device may include: forming an adhesive layer ( S110 ); acid-treating a surface of the adhesive layer to form a wrinkle region ( S120 ); and curing the adhesive layer ( S130 ).

[0090] At step S110, the hydrophobic surface treated fine particles having alkalinity may be mixed with the pressure sensitive adhesive resin solution so that an adhesive layer may be formed. The fine particles may include calcium carbonate (CaCO 3 ).

[0091] At step S120, an acidic solution may be brought into contact with the surface of the adhesive layer, thereby performing an acid treatment. Thus, fine particles located adjacent to the surface of the adhesive layer may be removed, so that a wrinkle region may be formed in the region of the adhesive layer where the fine particles are removed. The acidic solution may be dilute hydrochloric acid.

[0092] At step S130, the adhesive layer may be thermally cured. Accordingly, wrinkles may be formed on the surface of the adhesive layer in the wrinkle region.

[0093] The following will refer to Figure 8 The specific details of forming the folds are described.

[0094] The method of making an adhesive layer can be used to form Figures 1 to 5CThe first adhesive layer PSA1 and the second adhesive layer PSA2 of the display device of the present invention are shown in FIG. 1 , and the buffer plate CP including the corrugations may be manufactured by using a similar scheme.

[0095] Figure 8 is a flow chart of a method of manufacturing a lower plate for a display device according to the concept of the present invention.

[0096] Reference Figure 8 , the manufacturing method of the lower plate may include: forming a film layer (S210); acid-treating a surface of the film layer to form a wrinkle area (S220); curing the film layer (S230); and attaching a metal plate to the film layer (S240).

[0097] At step S210, fine particles containing calcium carbonate treated with a hydrophobic surface may be mixed with a resin solution so that a film layer may be formed. The calcium carbonate may have alkalinity. For example, a resin solution containing fine particles may be applied to a base film so that a film layer may be formed. The film layer may include a second portion and a third portion spaced apart from each other and a first portion arranged between the second portion and the third portion. The first portion may include fine particles, and the film layer may be formed to prevent the fine particles from being included in the second portion and the third portion.

[0098] The fine particles may have an average size of about 0.1 μm (micrometer) or less. For example, calcium carbonate (CaCO 3 ) has a size of about 0.03 μm. When mixed with an organic solution, since the fine particles may be unevenly dispersed due to precipitation or agglomeration, surface improvement is required in order to evenly disperse the fine particles and maintain the performance of the material. For surface improvement, the fine particles may be subjected to a hydrophobic surface treatment. For example, for surface improvement of fine particles containing calcium carbonate, ethanol:calcium carbonate (CaCO) may be mixed in a ratio of 10:1:0.4. 3 ): stearic acid, thereby providing hydrophobicity to the surface of the fine particles. Accordingly, when mixed with the resin solution to form a film layer, calcium carbonate (CaCO 3 ) can have a uniform distribution of fine particles.

[0099] For example, in the case of adding stearic acid, when the surface of the fine particles is treated by about 25%, the water content is relative to that of the particles containing calcium carbonate (CaCO 3 The contact angle of the surface of the fine particles of calcium carbonate (CaCO) can be 48°, and when the surface of the fine particles is subjected to about 50% surface treatment, the contact angle can be greater than 100°, so that 3 ) can be modified to be hydrophobic.

[0100] In exemplary embodiments, the resin solution may include thermally conductive balls, and thus the film layer may have thermal conductivity.

[0101] At step S220, an acidic solution may be brought into contact with the surface of the film layer to perform an acid treatment. Accordingly, fine particles positioned adjacent to the surface of the film layer may be removed, so that a wrinkled region may be formed in the region of the film layer from which the fine particles are removed. A first portion of the film layer containing fine particles may form a wrinkled region, and a second portion and a third portion of the film layer not containing fine particles may form a substantially flat region. For example, the film layer may be immersed in an acidic solution to perform an acid treatment. For example, fine particles of calcium carbonate having a high solubility in acid may be removed by using a 0.1 mol / L aqueous hydrochloric acid solution (HCl). Accordingly, voids may be formed on the surface of the film layer in the wrinkled region.

[0102] At step S230, the film layer may be thermally cured. The film layer may be thermally cured at a temperature greater than about 100°C. For example, the film layer may be cured for one hour by a hard baking process at a temperature of about 220°C. Accordingly, wrinkles may be formed on the surface of the film layer, so that a wrinkle region may be formed.

[0103] When the film layer is folded, the wrinkles formed can improve the strain rate by the height of the wrinkles. When it is assumed that the height of the film layer is about 100 μm, and when wrinkles are generated by uniformly removing fine particles containing calcium carbonate to a depth of about 10 μm from the surface of the film layer by immersing the film layer containing fine particles in a dilute hydrochloric acid solution for several minutes, the strain rate can be improved by about 10%, and the depth is about 10% of the height of the film layer.

[0104] The fine particles containing calcium carbonate may be distributed only in the wrinkle region and may not be distributed in the flat region. In this case, when the acid treatment is performed, wrinkles may be formed only in the wrinkle region even if the entire film layer is treated with an acid solution.

[0105] In another exemplary embodiment, the fine particles containing calcium carbonate may be distributed throughout the film layer. In this case, when the acid treatment is performed, only the wrinkled area of ​​the film layer may be treated with the acid solution.

[0106] At step S240, the metal plate may be attached to the top and bottom surfaces of the film layer. The metal plate and the film layer may be attached to each other using an adhesive layer.

[0107] Fig. 9 is a flowchart of a method of manufacturing a display device according to the concept of the present invention.

[0108] Reference Fig. 9 , the method of manufacturing a display device may include: forming a lower plate (S310); attaching a buffer plate to the lower plate (S320); attaching a display panel to the buffer plate (S330); and attaching a cover window to the display panel (S340).

[0109] At step S310, Figure 8 The lower plate is formed by the method described in .

[0110] At step S320, the buffer plate may be attached to the lower plate by using an adhesive layer. Figure 7 The method described in is formed.

[0111] At step S330, the display panel may be attached to the buffer plate by using an adhesive layer. The display panel may be a flexible display panel, and may be formed by using various known technologies.

[0112] At step S340, the cover window may be attached to the display panel by using an adhesive layer. Thus, the manufacture of the display device may be completed.

[0113] Fig. 10A and Fig. 10B is a diagram showing an example of the surface of a wrinkle region of a display device manufactured according to the concept of the present invention.

[0114] Fig. 10A and Fig. 10B The results of observations made using a scanning electron microscope (SEM) on the wrinkled surface of the film layer of the lower plate of the display device are shown. By using a dilute hydrochloric acid solution to remove calcium carbonate (CaCO 3 ) are thermally dried and transformed into wrinkles, thereby generating a new membrane structure with an increased elastic strain rate.

[0115] Fig.11 is a block diagram of an exemplary embodiment of an electronic device 500 including a display device 10 constructed according to the concepts of the present invention.

[0116] Reference Fig.11 , the electronic device 500 may include a processor 510, a memory device 520, a storage device 530, an input / output (I / O) device 540, a power supply 550, and a display device 560. Here, the display device 560 may be Figure 1 The electronic device 500 may further include a plurality of ports for communicating with a video card, a sound card, a memory card, a universal serial bus (USB) device, other electronic devices, etc. In an exemplary embodiment, the electronic device 500 may be implemented as a television. In another exemplary embodiment, the electronic device 500 may be implemented as a smart phone. However, the electronic device 500 is not limited thereto. For example, the electronic device 500 may be implemented as a cellular phone, a video phone, a smart tablet, a smart watch, a tablet computer, a car navigation system, a computer display screen, a laptop, a head mounted display (HMD) device, etc.

[0117] The processor 510 may perform various computing functions. The processor 510 may be a microprocessor, a central processing unit (CPU), an application processor (AP), etc. The processor 510 may be connected to other components via an address bus, a control bus, a data bus, etc. In addition, the processor 510 may be connected to an expansion bus such as a peripheral component interconnection (PCI) bus. The memory device 520 may store data used for the operation of the electronic device 500. For example, the memory device 520 may include at least one nonvolatile memory device and / or at least one volatile memory device, wherein the at least one nonvolatile memory device is such as an erasable programmable read-only memory (EPROM) device, an electrically erasable programmable read-only memory (EEPROM) device, a flash memory device, a phase change random access memory (PRAM) device, a resistance random access memory (RRAM) device, a nano floating gate memory (NFGM) device, a polymer random access memory (PoRAM) device, a magnetic random access memory (MRAM) device, a ferroelectric random access memory (FRAM) device, etc., and the at least one volatile memory device is such as a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, etc. The storage device 530 may include a solid state drive (SSD) device, a hard disk drive (HDD) device, a CD-ROM device, etc. The I / O device 540 may include an input device and an output device, the input device being such as a keyboard, a keypad, a mouse device, a touch pad, a touch screen, etc., and the output device being such as a printer, a speaker, etc. The power supply 550 may provide power for the operation of the electronic device 500.

[0118] The display device 560 may be connected to other components via a bus or other communication links. In some exemplary embodiments, the I / O device 540 may include a display device 560. As described above, since the display device 560 includes a layer including a wrinkle region in a foldable region, the layer may have a high strain rate. Accordingly, when the display device 560 is folded and unfolded, the shear stress at the interface between the layers can be reduced, and wrinkle deformation, bubble generation, or the like caused by the repulsive force due to the difference in curvature of the interface between the layers can be prevented or at least reduced. Since these are described above, for the sake of brevity, repeated descriptions related thereto will be omitted.

[0119] Although certain exemplary embodiments and implementations have been described herein, other embodiments and variations will be apparent from this description. Accordingly, the inventive concept is not limited to such embodiments, but rather to the broader scope of the appended claims and to various obvious variations and equivalent arrangements apparent to those of ordinary skill in the art.

Claims

1. A display device, comprising a first non-foldable area, a second non-foldable area spaced apart from the first non-foldable area, and a foldable area arranged between the first non-foldable area and the second non-foldable area, the display device comprising: Supporting member; a first adhesive layer disposed on the support member; a buffer member disposed on the first adhesive layer; a second adhesive layer disposed on the buffer member; as well as a flexible display panel, the flexible display panel being arranged on the second adhesive layer, wherein the supporting member comprises a first region, the first region overlapping the foldable region, The supporting member includes a lower plate, the lower plate includes: a first metal layer; a film layer, the film layer is arranged on the first metal layer, the film layer includes the first region; and a second metal layer, the second metal layer is arranged on the film layer. The first region includes a first wrinkle region having wrinkles formed on a top surface or a bottom surface of the film layer.

2. The display device according to claim 1, wherein: The buffer member comprises a buffer plate, the buffer plate comprises a second area overlapping the foldable area, the second area having at least one second concave-convex body for easy bending; The first region has a first width; and The second region has a second width greater than the first width.

3. The display device according to claim 2, wherein: The second region includes a second corrugated region having corrugations formed on a surface of the buffer panel, and the second region of the buffer panel partially overlaps the first non-foldable region and the second non-foldable region.

4. The display device according to claim 1, wherein: The lower plate also includes: a lower adhesive layer disposed between the first metal layer and the film layer; and An upper adhesive layer is disposed between the film layer and the second metal layer.

5. The display device according to claim 1, wherein: The film layer of the support member includes a resin layer having thermally conductive balls.

6. The display device according to claim 1, wherein: The first region includes a first wrinkle region having wrinkles formed on an opposite surface of the top surface or the bottom surface of the film layer.

7. The display device according to claim 1, wherein: The first adhesive layer includes a third area overlapping the foldable area, and the second adhesive layer includes a fourth area overlapping the foldable area, and at least one of the third area and the fourth area has at least one concavo-convex body to facilitate folding.

8. The display device according to claim 1, wherein: The film layer overlapping the first region includes fine particles containing calcium carbonate.

9. A method for manufacturing a display device, the method comprising the following steps: forming a film layer by using a resin solution including a plurality of fine particles having alkalinity; performing an acid treatment to remove some of the plurality of fine particles adjacent to a surface of the film layer by allowing an acidic solution to contact the film layer; forming wrinkles on the surface of the film layer by curing the acid-treated film layer; as well as A display panel is attached to the film layer having the corrugations.

10. The method of claim 9, wherein: The plurality of fine particles include calcium carbonate.

11. The method of claim 10, wherein: Multiple surfaces of the multiple fine particles are hydrophobically treated.

12. The method of claim 11, wherein: The hydrophobic treatment is performed by mixing the plurality of fine particles including the calcium carbonate with ethanol and stearic acid.

13. The method of claim 10, wherein: The acidic solution includes dilute hydrochloric acid.

14. The method of claim 9, wherein: When curing the acid-treated film layer, the film layer is thermally cured at a temperature higher than 100°C.

15. The method of claim 9, wherein: The plurality of fine particles have an average size of less than 0.1 μm.

16. The method of claim 9, further comprising the steps of: Before attaching the display panel to the film layer, a metal plate is attached to the film layer.

17. The method of claim 16, further comprising the steps of: Before attaching the display panel to the film layer, a buffer plate is attached to the metal plate.

18. The method of claim 9, wherein: The film layer includes a corrugated area having the corrugations and a plurality of flat areas spaced apart from each other, and the corrugated area is formed between the plurality of flat areas.

19. A display device comprising: A flexible display panel having a foldable area; as well as a film layer, wherein the film layer is arranged below the flexible display panel, wherein the entire film layer or a region of the film layer overlapping the foldable region comprises fine particles containing calcium carbonate, and The entire film layer or the region is subjected to acid treatment to form a wrinkled region on the top surface or the bottom surface of the region of the film layer.

Images