Display device

Abstract

A display device is provided. The display device includes a display panel, a window disposed on the display panel, a window protective layer disposed on the window, and a first adhesive layer disposed between the window and the window protective layer. The first adhesive layer has a creep value of about 38.1876% to about 40.4371% at a temperature of about 25°C when a stress of about 2000 Pa is applied to it for about 10 minutes. When a frequency of about 1 Hz and an axial force of about 1.0 N are applied and the first adhesive layer maintains a strain of about 1%, the first adhesive layer has a storage modulus of about 0.0317 MPa to about 0.0348 MPa, a loss modulus of about 0.0108 MPa to about 0.0120 MPa, and a loss tangent of about 0.3359 to about 0.3480 at a temperature of about 25°C, wherein the loss tangent is defined as the loss modulus divided by the storage modulus.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2019-0165451, filed on December 12, 2019, which is incorporated herein by reference for all purposes as if fully set forth herein. Technical Field

[0003] Exemplary implementations of the present invention generally relate to display devices, and more specifically, to display devices including an adhesive layer. Background Technology

[0004] Electronic devices such as smartphones, digital cameras, laptops, navigation units, and smart TVs include display devices that display images to users. The display device generates images to provide the generated images to the user via a screen.

[0005] In recent years, with the advancement of display device technology, various types of display devices have been developed. For example, foldable and rollable flexible display devices have been developed. Flexible display devices that can be deformed into various shapes are portable, thus increasing user convenience.

[0006] The display device may include a display panel, a window disposed on the display panel, and a window protective layer disposed on the window. An adhesive layer may be disposed between the window protective layer and the window to attach the window protective layer to the window.

[0007] The information disclosed in this background section is only for understanding the background of the concept of the present invention, and therefore may contain information that does not constitute prior art. Summary of the Invention

[0008] The applicant discovered that the adhesive layer could deform when the window protective layer of the display device was pressed and attached to the window, or when the display device was repeatedly folded.

[0009] The display device constructed according to the principles and exemplary implementations of the present invention includes an adhesive layer having high elasticity, low strain, and high adhesion.

[0010] Additional features of the inventive concept will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the inventive concept.

[0011] According to one aspect of the present invention, a display device includes a display panel, a window disposed on the display panel, a window protective layer disposed on the window, and a first adhesive layer disposed between the window and the window protective layer, wherein, when a stress of about 2000 Pa is applied to the first adhesive layer for about 10 minutes, the first adhesive layer has a creep value of about 38.1876% to about 40.4371% at a temperature of about 25°C, and when a frequency of about 1 Hz and an axial force of about 1.0 N are applied and the first adhesive layer maintains a strain of about 1%, the first adhesive layer has a storage modulus of about 0.0317 MPa to about 0.0348 MPa, a loss modulus of about 0.0108 MPa to about 0.0120 MPa, and a loss tangent of about 0.3359 to about 0.3480 at a temperature of about 25°C, and the loss tangent is defined as the loss modulus divided by the storage modulus.

[0012] The first adhesive layer may have a storage modulus of about 0.1463 MPa to about 0.1994 MPa, a loss modulus of about 0.1458 MPa to about 0.2071 MPa, and a loss tangent of about 0.9885 to about 1.0519 at a temperature of about -20°C.

[0013] The first adhesive layer may have a storage modulus of about 0.0490 MPa to about 0.0629 MPa, a loss modulus of about 0.0229 MPa to about 0.0318 MPa, and a loss tangent of about 0.4673 to about 0.5056 at a temperature of about 2°C.

[0014] The first adhesive layer may have a storage modulus of about 0.0181 MPa to about 0.0243 MPa, a loss modulus of about 0.0073 MPa to about 0.0102 MPa, and a loss tangent of about 0.4033 to about 0.4309 at a temperature of about 60°C.

[0015] The first adhesive layer may have a storage modulus of about 0.0137 MPa to about 0.0215 MPa, a loss modulus of about 0.0058 MPa to about 0.0095 MPa, and a loss tangent of about 0.4173 to about 0.4455 at a temperature of about 85°C.

[0016] After approximately 10 minutes following the removal of the stress applied to the first adhesive layer, the first adhesive layer may have a residual strain of approximately 7.0426% to approximately 8.0211% at a temperature of approximately 25°C.

[0017] When a stress of about 2000 Pa is applied to the first adhesive layer for about 10 minutes, the first adhesive layer can have a creep value of about 52.3894% to about 59.9129% at a temperature of about 60°C.

[0018] After approximately 10 minutes following the removal of the stress applied to the first adhesive layer, the first adhesive layer may have a residual strain of approximately 6.3912% to approximately 8.5546% at a temperature of approximately 60°C.

[0019] The first adhesive layer may have a thickness of about 10 μm to about 50 μm.

[0020] The first adhesive layer may be made of silicone resin, acrylic resin or urethane resin.

[0021] The window protective layer may include at least one polymer resin selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, polystyrene, polyvinyl chloride, polyethersulfone, polypropylene, polyamide, modified polyphenylene ether, polyoxymethylene, polysulfone, polyphenylene sulfide, polyimide, polyethyleneimine, polyetheretherketone, polyamide-imide, polyarylate, and thermoplastic polyurethane.

[0022] The display device may further include an input sensor disposed on the display panel, an anti-reflective layer disposed between the input sensor and a window, a protective layer disposed below the display panel, a support member disposed below the protective layer, a second adhesive layer disposed between the window and the anti-reflective layer, a third adhesive layer disposed between the anti-reflective layer and the input sensor, a fourth adhesive layer disposed between the display panel and the protective layer, and a fifth adhesive layer disposed between the protective layer and the support member, wherein at least one of the second, third, fourth, and fifth adhesive layers has substantially the same physical properties as the first adhesive layer.

[0023] Windows may include glass.

[0024] The adhesion force of the first adhesive layer to the window can be about 810 ± 25 gf / in at a temperature of about 25°C, and the adhesion force can be the peel force value when the window protective layer is attached to the window through the first adhesive layer and peeled off from the window after about 30 minutes.

[0025] The adhesion force of the first adhesive layer to the window can be approximately 256 ± 17 gf / in at a temperature of approximately 80°C, and the adhesion force can be the peel force value when the window protective layer is attached to the window through the first adhesive layer and peeled off from the window after approximately 30 minutes.

[0026] At least one of the display panel and the window protective layer can be folded inward or outward relative to the folding axis.

[0027] The input sensor may include an input sensing part, and the support member may include a support part.

[0028] According to another aspect of the present invention, a display device includes a display panel, a window disposed on the display panel, a window protective layer disposed on the window, and an adhesive layer disposed between the window and the window protective layer, wherein the adhesive force of the adhesive layer relative to the window is about 810±25 gf / in at a temperature of about 25°C, and the adhesive force of the adhesive layer relative to the window is about 256±17 gf / in at a temperature of about 80°C, and the adhesive force is the peel force value when the window protective layer is attached to the window through the adhesive layer and peeled off from the window after about 30 minutes.

[0029] When a stress of about 2000 Pa is applied to the adhesive layer for about 10 minutes, the adhesive layer can have a creep value of about 38.3271% to about 40.4371% at a temperature of about 25°C, and when a frequency of about 1 Hz and an axial force of about 1.0 N are applied and the adhesive layer can maintain a strain of about 1%, the adhesive layer can have a storage modulus of about 0.0317 MPa to about 0.0348 MPa and a loss modulus of about 0.0108 MPa to about 0.0120 MPa at a temperature of about 25°C.

[0030] It will be understood that the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the claimed invention. Attached Figure Description

[0031] 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 concepts of the invention.

[0032] Figure 1 This is a perspective view illustrating an exemplary embodiment of a display device constructed according to the principles of the present invention.

[0033] Figure 2 It is shown Figure 1 A perspective view of the folded state of the display device.

[0034] Figure 3 This is a perspective view illustrating another exemplary embodiment of a display device constructed according to the principles of the present invention.

[0035] Figure 4 It is shown Figure 3 A perspective view of the folded state of the display device.

[0036] Figure 5 yes Figure 1 A cross-sectional view of the display device.

[0037] Figure 6 It is shown Figure 5 A cross-sectional view of the display panel.

[0038] Figure 7 It shows the arrangement in Figure 6 A schematic cross-sectional view of representative pixels in the pixel layer.

[0039] Figure 8 It is based on the principle of the present invention. Figure 5 A cross-sectional view of an exemplary method for attaching a window protective layer to a window.

[0040] Figure 9 It is shown Figure 5 A cross-sectional view of the display device in its inward-folded state.

[0041] Figure 10 It is used for measurement Figure 5 A perspective view of the method for applying adhesive force to the first adhesive layer.

[0042] Figure 11 The graph depicts the average values ​​of the storage modulus and loss modulus of the first adhesive layer, produced according to the principle of the invention, at temperatures of approximately 2°C and approximately 25°C, and compares the average values ​​of the storage modulus and loss modulus of the adhesive layer.

[0043] Figure 12 The graph depicts the average value of the loss tangent of the first adhesive layer and the average value of the loss tangent of the comparative adhesive layers, which were produced according to the principle of the present invention at temperatures of approximately 2°C and approximately 25°C.

[0044] Figure 13 It is a graphical depiction of the average creep value of the first adhesive layer made according to the principle of the present invention at temperatures of about 25°C and about 60°C, and the average creep value of the comparative adhesive layers. Detailed Implementation

[0045] In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of various exemplary embodiments or implementations of the invention. As used herein, “embodiment” and “implementation” are interchangeable terms and are non-limiting examples of apparatus or methods employing one or more of the inventive concepts disclosed herein. However, it will be apparent, however, that various exemplary embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and apparatuses are shown in block diagram form to avoid unnecessarily obscuring various exemplary embodiments. Furthermore, the various exemplary embodiments may be different, but are not necessarily exclusive. For example, a particular shape, configuration, and feature of an exemplary embodiment may be used or implemented in another exemplary embodiment without departing from the inventive concept.

[0046] Unless otherwise stated, the exemplary embodiments shown are to be understood as providing exemplary features detailing variations in some ways in which the inventive concept can be implemented in practice. Therefore, unless otherwise stated, features, components, modules, layers, films, panels, areas and / or aspects of various embodiments (hereinafter individually or collectively referred to as “elements”) may be combined, separated, interchanged and / or rearranged in other ways without departing from the inventive concept.

[0047] Crosshairs and / or shading are generally provided in the accompanying drawings to clarify the boundaries between adjacent elements. Thus, unless otherwise stated, the presence or absence of crosshairs or shading does not convey or indicate any preference or requirement for specific materials, material properties, dimensions, scale, commonalities between the shown elements, or / or any other characteristics, properties, or characteristics of the elements. Furthermore, in the drawings, the size and relative size of elements may be exaggerated for clarity and / or descriptive purposes. When exemplary embodiments can be implemented differently, a particular order of processes may be performed differently than the order described. For example, two consecutively described processes may be performed substantially simultaneously or in the reverse order of their description. Additionally, the same reference numerals denote the same elements.

[0048] When an element, layer, component, area, or part is referred to as being "on," "connected to," or "coupled to" another element, layer, component, area, or part, it may be directly connected to or directly coupled to the other element, layer, component, area, or part, or there may be intermediate elements, layers, components, areas, or parts. However, when an element, layer, component, area, or part is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, layer, component, area, or part, there are no intermediate elements, layers, components, areas, or parts. For this purpose, the term "connection" may refer to a physical, electrical, and / or fluid connection with or without intermediate elements. Furthermore, the D1, D2, and D3 axes are not limited to the three axes of a Cartesian coordinate system, such as the x-axis, y-axis, and z-axis, and can be interpreted in a broader sense. For example, axes D1, D2, and D3 can be perpendicular to each other, or they can represent different directions that are not perpendicular to each other. For the purposes 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" can be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as 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.

[0049] Although the terms “first,” “second,” etc., may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Therefore, without departing from the teachings of this disclosure, the first element discussed below may be referred to as the second element.

[0050] Spatial relation terms, such as “below,” “under,” “below,” “lower,” “above,” “upper,” “above,” “higher,” “side” (e.g., as in “sidewall”), etc., are used herein for descriptive purposes and thus to describe the relationship between one element(s) and another(s) as shown in the figures. Spatial relation terms are intended to cover different orientations of the device in use, operation, and / or manufacture other than those depicted in the figures. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features would be oriented as “above” other elements or features. Thus, the exemplary term “below” can include both upper and lower orientations. Furthermore, the device may be oriented in other ways (e.g., rotated 90 degrees or located in other orientations), and therefore, the spatial relation descriptive terms used herein are interpreted accordingly.

[0051] The wording used herein is for the purpose of describing particular embodiments and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein are intended to also include the plural forms. Furthermore, the terms “comprise,” “comprising,” “include,” and / or “including”, when used in this specification, specify the presence of the referred features, properties, fixed quantities, integrals, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, properties, fixed quantities, integrals, steps, operations, elements, components, and / or groups thereof. It should also be noted that, as used herein, the terms “substantially,” “about,” and other similar terms are used as approximate terms and not as terms of degree, and are therefore used to explain inherent deviations in measured, calculated, and / or provided values ​​that would be recognized by those skilled in the art.

[0052] This document describes various exemplary embodiments with reference to cross-sectional views and / or exploded views, which are schematic representations of idealized exemplary embodiments and / or intermediate structures. Thus, variations in the illustrated shapes, for example due to manufacturing techniques and / or tolerances, are to be expected. Therefore, the exemplary embodiments disclosed herein should not necessarily be interpreted as limited to the specific illustrated shapes of the areas, but rather include shape deviations caused, for example, by manufacturing processes. In this way, the areas shown in the figures can be schematic in nature, and the shapes of these areas may not reflect the actual shapes of the areas of the device, and are therefore not necessarily intended to be limiting.

[0053] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms such as those defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field, and shall not be interpreted in an ideal or overly rigid sense unless expressly so defined herein.

[0054] Figure 1 This is a perspective view illustrating an exemplary embodiment of a display device constructed according to the principles of the present invention. Figure 2 It is shown Figure 1 A perspective view of the folded state of the display device.

[0055] Reference Figure 1 According to an exemplary embodiment, the display device DD may have a generally rectangular shape with its long side along a first direction DR1 and its short side along a second direction DR2 intersecting the first direction DR1. However, the exemplary embodiment is not limited thereto. For example, the display device DD may have various shapes, such as a generally circular shape or a generally polygonal shape. The display device DD may generally be a flexible display device.

[0056] As discussed herein, the direction that intersects the plane defined by the first direction DR1 and the second direction DR2 in a substantially perpendicular manner is defined as the third direction DR3.

[0057] The display device DD may include a folded region FA and multiple non-folded regions NFA1 and NFA2. The non-folded regions NFA1 and NFA2 may include a first non-folded region NFA1 and a second non-folded region NFA2. The folded region FA may be arranged between the first non-folded region NFA1 and the second non-folded region NFA2. The folded region FA, the first non-folded region NFA1, and the second non-folded region NFA2 may be arranged in a first direction DR1.

[0058] Although an exemplary embodiment shows one folded region FA and two non-folded regions NFA1 and NFA2, some exemplary embodiments are not limited to the respective number of folded regions FA and non-folded regions NFA1 and NFA2. For example, the display device DD may include two or more non-folded regions and a plurality of folded regions arranged between the two or more non-folded regions.

[0059] The top surface of the display device DD may be defined as a display surface DS, and may have a plane defined by a first direction DR1 and a second direction DR2. The image IM generated in the display device DD can be provided to the user through the display surface DS.

[0060] The display surface DS may include a display area DA and a non-display area NDA surrounding the display area DA. The display area DA may display an image IM, and the non-display area NDA may not display an image. The non-display area NDA may define an edge surrounding the display area DA and printed in a predetermined color.

[0061] Reference Figure 2 The display device DD can be folded or unfolded. For example, the display device DD can be folded such that the folded area FA bends relative to a folding axis FX that is substantially parallel to the second direction DR2. The folding axis FX can be defined as a short axis that is substantially parallel to the short side of the display device DD.

[0062] When the display device DD is folded, the first non-folded area NFA1 and the second non-folded area NFA2 can face each other, and the display device DD can be folded inward (inward fold) so that the display surface DS is not exposed to the outside.

[0063] Figure 3 This is a perspective view illustrating another exemplary embodiment of a display device constructed according to the principles of the present invention. Figure 4 It is shown Figure 3 A perspective view of the folded state of the display device.

[0064] In addition to folding operations, Figure 3 The display device DD_1 in the middle can be with Figure 1 The display device DD has a substantially identical configuration. Therefore, the following description will primarily focus on the folding operation of the display device DD_1, and descriptions of similar components will be omitted to avoid redundancy.

[0065] Reference Figure 3 and Figure 4The display device DD_1 may include a folded region FAa and multiple non-folded regions NFA1a and NFA2a. The non-folded regions NFA1a and NFA2a may include a first non-folded region NFA1a and a second non-folded region NFA2a. The folded region FAa may be arranged between the first non-folded region NFA1a and the second non-folded region NFA2a. The folded region FAa, the first non-folded region NFA1a, and the second non-folded region NFA2a may be arranged in a second direction DR2.

[0066] The display device DD_1 can be folded such that the folded area FAa is bent relative to a folding axis FXa that is substantially parallel to the first direction DR1. The folding axis FXa can be defined as a major axis that is substantially parallel to the long side of the display device DD_1. Figure 1 The display device DD in the middle can be folded relative to the short side, and unlike this, Figure 3 The display device DD_1 can be folded relative to its long side. The display device DD_1 can be folded inward so that the display surface DS is not exposed to the outside.

[0067] Although display devices DD and DD_1 are described exemplarily inwardly folded relative to folding axes FX and FXa, the exemplary embodiments are not limited to the folding operation of display devices DD and DD_1. For example, each of display devices DD and DD_1 may be folded outward (outward folding) so that the display surface DS is exposed to the outside.

[0068] Figure 5 yes Figure 1 A cross-sectional view of the display device.

[0069] Reference Figure 5 The display device DD may include a display panel DP, an input sensor (which may be an input sensing unit ISP), an anti-reflective layer RPL, a window WIN, a window protective layer WPL, a protective layer PL, a support member (which may be a support unit SUP), and first adhesive layers AL1 to fifth adhesive layers AL5. The input sensing unit ISP, the anti-reflective layer RPL, the window WIN, and the window protective layer WPL may be arranged on the display panel DP, and the protective layer PL and the support unit SUP may be arranged below the display panel DP.

[0070] The display panel DP can be flexible. For example, the display panel DP may include multiple electronic components arranged on a flexible display panel. The display panel DP may include a first non-folding region NFA1, a second non-folding region NFA2, and a folding region FA arranged between the first non-folding region NFA1 and the second non-folding region NFA2.

[0071] The display panel DP according to the exemplary embodiments may be a light-emitting display panel. However, the exemplary embodiments are not limited thereto. For example, the display panel DP may be an organic light-emitting display panel, a quantum dot light-emitting display panel, or other types of display panels. An organic light-emitting display panel may include a light-emitting layer comprising organic light-emitting materials. A quantum dot light-emitting display panel may include a light-emitting layer comprising quantum dots or quantum rods. Hereinafter, for ease of description, the display panel DP will be described as an organic light-emitting display panel.

[0072] An input sensing unit (ISP) may be disposed on a display panel (DP). The input sensing unit (ISP) may include multiple sensors to detect external input. The sensors may detect external input using capacitive methods. The input sensing unit (ISP) may be manufactured directly on the display panel (DP) during the manufacturing process. However, exemplary embodiments are not limited thereto. The input sensing unit (ISP) may be manufactured as a panel separate from the display panel (DP) and then attached to the display panel (DP) via an adhesive layer.

[0073] An anti-reflective layer RPL may be disposed between the input sensing unit ISP and the window WIN. The anti-reflective layer RPL may be defined as an anti-external light reflection film. The anti-reflective layer RPL can reduce the reflectivity of external light incident from above the display device DD toward the display panel DP. For example, the anti-reflective layer RPL may include a retarder and / or a polarizer.

[0074] The window (WIN) is positioned on the anti-reflective layer (RPL). The window protects the display panel (DP), input sensor (ISP), and anti-reflective layer (RPL) from external scratches and impacts. The window can be optically transparent.

[0075] A window protective layer (WPL) may be disposed on the window (WIN). The WPL protects the window (WIN). The WPL may be optically transparent. Therefore, the image generated in the display panel (DP) can pass through the window (WIN) and the WPL and be provided to the user. A protective layer (PL) may be disposed below the display panel (DP). The PL may be defined as a protective substrate. The PL protects the lower part of the display panel (DP). The PL may contain a plastic material. For example, the PL may contain polyethylene terephthalate (PET).

[0076] The support portion SUP can be disposed below the protective layer PL. The support portion SUP can support the display panel DP. The support portion SUP may include a first support portion SUP1 overlapping the first non-folding region NFA1 and a second support portion SUP2 overlapping the second non-folding region NFA2. The first support portion SUP1 can support the first non-folding region NFA1, and the second support portion SUP2 can support the second non-folding region NFA2.

[0077] Each of the first support portion SUP1 and the second support portion SUP2 may contain metal. For example, each of the first support portion SUP1 and the second support portion SUP2 may contain stainless steel, aluminum, or an alloy thereof. Each of the first support portion SUP1 and the second support portion SUP2 may have a strength greater than that of the display panel DP.

[0078] A padding layer may be disposed between the protective layer PL and the support SUP. The padding layer can absorb external impacts acting on the lower part of the display device DD to protect the display panel DP. The padding layer may include a foam sheet with a predetermined elasticity.

[0079] A first adhesive layer AL1 may be disposed between the window protective layer WPL and the window WIN. The window protective layer WPL and the window WIN can be attached to each other through the first adhesive layer AL1.

[0080] A second adhesive layer AL2 may be disposed between the window WIN and the anti-reflective layer RPL. The window WIN and the anti-reflective layer RPL can be attached to each other through the second adhesive layer AL2. A third adhesive layer AL3 may be disposed between the anti-reflective layer RPL and the input sensing unit ISP. The anti-reflective layer RPL and the input sensing unit ISP can be attached to each other through the third adhesive layer AL3.

[0081] A fourth adhesive layer AL4 may be disposed between the display panel DP and the protective layer PL. The display panel DP and the protective layer PL can be attached to each other through the fourth adhesive layer AL4.

[0082] A fifth adhesive layer AL5 may be disposed between the protective layer PL and the support portion SUP. The protective layer PL and the support portion SUP can be attached to each other through the fifth adhesive layer AL5. Although each of the first adhesive layers AL1 to the fifth adhesive layer AL5 may include, for example, a pressure-sensitive adhesive, the exemplary embodiments are not limited thereto. For example, each of the first adhesive layers AL1 to the fifth adhesive layer AL5 may include various adhesives. Each of the first adhesive layers AL1 to the fifth adhesive layer AL5 may include a silicone resin, an acrylic resin, or a urethane resin. Each of the first adhesive layers AL1 to the fifth adhesive layer AL5 may include a polymer resin comprising a silicone resin, an acrylic resin, or a urethane resin. For example, each of the first adhesive layers AL1 to the fifth adhesive layer AL5 may be made of an acrylic resin.

[0083] Figure 6 It is shown Figure 5 A cross-sectional view of the display panel.

[0084] Reference Figure 6 The display panel DP may include a substrate SUB, a pixel layer PXL disposed on the substrate SUB, and a thin film encapsulation layer TFE disposed on the substrate SUB to cover the pixel layer PXL.

[0085] The substrate SUB may include a display area DA and a non-display area NDA surrounding the display area DA. The substrate SUB may contain a flexible plastic material. For example, the substrate SUB may contain polyimide (PI). The pixel layer PXL may include multiple pixels. The configuration of each pixel will be described in detail below.

[0086] The thin-film encapsulation layer (TFE) may include at least two inorganic layers and an organic layer disposed between the inorganic layers. The inorganic layers may contain inorganic materials and protect the pixel layer (PXL) from moisture and oxygen. The organic layer may contain organic materials and protect the pixel layer (PXL) from foreign matter such as dust particles. The aforementioned input sensing unit (ISP) may be disposed on the thin-film encapsulation layer (TFE).

[0087] Figure 7 It shows the arrangement in Figure 6 A schematic cross-sectional view of representative pixels in the pixel layer.

[0088] Reference Figure 6 and Figure 7 , Figure 7 Multiple pixels (PX) can be set within the pixel layer (PXL). A representative pixel (PX) may include an OLED light-emitting element and a transistor (TR) connected to the OLED light-emitting element.

[0089] An OLED (Organic Light-Emitting Device) may include a first electrode AE, a second electrode CE, a hole control layer HCL, an electron control layer ECL, and an emissive layer EML. The first electrode AE ​​may be an anode electrode, and the second electrode CE may be a cathode electrode. The OLED may be defined as an organic light-emitting device.

[0090] Transistor TR and light-emitting element OLED can be arranged on substrate SUB. Substrate SUB may include a light-emitting region PXA corresponding to each pixel PX and a non-light-emitting region NPXA arranged around the light-emitting region PXA. Light-emitting element OLED can be arranged on light-emitting region PXA, and transistor TR can be arranged on non-light-emitting region NPXA.

[0091] A buffer layer BFL may be disposed on the substrate SUB. The buffer layer BFL may contain inorganic materials. The semiconductor layer SM of the transistor TR may be disposed on the buffer layer BFL. The semiconductor layer SM may include organic semiconductors and semiconductors made of inorganic materials such as amorphous silicon or polycrystalline silicon. Alternatively, the semiconductor layer SM may include oxide semiconductors.

[0092] The semiconductor layer SM may include a source region, a drain region, and a channel region disposed between the source region and the drain region.

[0093] A first insulating layer INS1 may be disposed on a buffer layer BFL to cover the semiconductor layer SM. The first insulating layer INS1 may contain inorganic material. The gate electrode GE of the transistor TR, which overlaps with the semiconductor layer SM, may be disposed on the first insulating layer INS1. The gate electrode GE may be arranged to overlap with the channel region of the semiconductor layer SM.

[0094] A second insulating layer INS2 may be disposed on the first insulating layer INS1 to cover the gate electrode GE. The second insulating layer INS2 may contain organic and / or inorganic materials.

[0095] The source electrode SE and drain electrode DE of transistor TR are spaced apart from each other on the second insulating layer INS2. The source electrode SE can be connected to the source region of semiconductor layer SM through a first contact hole CH1 passing through the first insulating layer INS1 and the second insulating layer INS2. The drain electrode DE can be connected to the drain region of semiconductor layer SM through a second contact hole CH2 passing through the first insulating layer INS1 and the second insulating layer INS2.

[0096] A third insulating layer INS3 may be disposed on the second insulating layer INS2 to cover the source electrode SE and drain electrode DE of the transistor TR. The third insulating layer INS3 may contain an organic material. A connection electrode CNE may be disposed on the third insulating layer INS3. The connection electrode CNE may be connected to the drain electrode DE through a third contact hole CH3 defined in the third insulating layer INS3.

[0097] A fourth insulating layer INS4 may be disposed on the third insulating layer INS3 to cover the connecting electrode CNE. A first electrode AE ​​may be disposed on the fourth insulating layer INS4. The first electrode AE ​​may be connected to the connecting electrode CNE through a fourth contact hole CH4 defined in the fourth insulating layer INS4.

[0098] A pixel defining layer PDL, exposing a predetermined portion of the first electrode AE, may be disposed on the first electrode AE ​​and the fourth insulating layer INS4. An opening PX-OP for exposing the predetermined portion of the first electrode AE ​​may be defined in the pixel defining layer PXL.

[0099] The hole control layer (HCL) can be disposed on the first electrode (AE) and the pixel definition layer (PDL). The hole control layer (HCL) can also be commonly disposed on the light-emitting region (PXA) and the non-light-emitting region (NPXA). The hole control layer (HCL) may include a hole transport layer and a hole injection layer.

[0100] The emissive layer EML can be disposed on the hole control layer HCL. The emissive layer EML can be disposed in the region corresponding to the opening PX_OP. That is, the emissive layer EML can be individually disposed in each of the pixels PX. The emissive layer EML can contain organic and / or inorganic materials. Although the emissive layer EML can generate one of red, green, and blue light, the exemplary embodiments are not limited thereto. For example, the emissive layer EML can generate white light by a combination of organic materials that each generate red, green, and blue light.

[0101] An electron control layer (ECL) may be disposed on the light-emitting layer (EML). The ECL may also be disposed on the hole control layer (HCL) to cover the EML. That is, the ECL may be commonly disposed on the light-emitting region (PXA) and the non-light-emitting region (NPXA). The ECL may include an electron transport layer and also an electron injection layer.

[0102] The second electrode CE can be disposed on the substrate SUB. The second electrode CE can also be disposed on the pixel PX. The thin-film encapsulation layer TFE can be disposed on the second electrode CE. The layer disposed between the substrate SUB and the thin-film encapsulation layer TFE can be defined as the pixel layer PXL.

[0103] A first voltage can be applied to the first electrode AE, and a second voltage with a lower level than the first voltage can be applied to the second electrode CE. In this case, holes and electrons injected into the light-emitting layer EML can couple with each other to provide excitons, and when the excitons transition to the ground state, the light-emitting element OLED can emit light. The light-emitting element OLED can emit light to display an image.

[0104] Figure 8 It is based on the principle of the present invention. Figure 5 A cross-sectional view of an exemplary method for attaching a window protective layer to a window. Figure 9 It is shown Figure 5 A cross-sectional view of the display device in its inward-folded state.

[0105] Reference Figure 5 and Figure 8 The window WIN, anti-reflective layer RPL, input sensor ISP, display panel DP, protective layer PL, and support SUP can be attached to each other via the second adhesive layer AL2 to the fifth adhesive layer AL5. The window protective layer WPL and the first adhesive layer AL1 can be disposed on the window WIN. The first adhesive layer AL1 can be attached to the bottom surface of the window protective layer WPL facing the window WIN. The first adhesive layer AL1 can have a thickness of approximately 10 μm to approximately 50 μm.

[0106] The window WM may include glass. The window protective layer WPL may be a polymer film of at least one polymer resin selected from polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), polyvinyl chloride (PVC), polyethersulfone (PES), polypropylene (PP), polyamide (PA), modified polyphenylene ether (m-PPO), polyoxymethylene (POM), polysulfone (PSU), polyphenylene sulfide (PPS), polyimide (PI), polyethyleneimine (PEI), polyetheretherketone (PEEK), polyamide-imide (PAI), polyarylate (PAR), and thermoplastic polyurethane (TPU).

[0107] The first adhesive layer AL1 can be attached to the top surface of the window WIN facing the window protective layer WPL. The window protective layer WPL can be pressed down and attached to the window WIN. This process can be defined as a pressing process.

[0108] The first adhesive layer AL1 can have high elasticity, low strain, and high adhesion. Therefore, even though the window protective layer WPL is pressed against the first adhesive layer AL1, the elasticity and adhesion of the first adhesive layer AL1 can be maintained, and the deformation of the first adhesive layer AL1 can be reduced.

[0109] Although, by way of example, the first adhesive layer AL1 is first attached to the window protective layer WPL, the exemplary embodiments are not limited thereto. For example, the first adhesive layer AL1 may be first attached to the window WIN, and then the window protective layer WPL may be pressed against the window WIN.

[0110] The experimental data of a first adhesive layer AL1 having high elasticity, low strain, and high adhesion according to some exemplary embodiments are described in detail below with reference to comparative examples.

[0111] Although the method of attaching the window protective layer WPL to the window WIN via the first adhesive layer AL1 has been described as an example, the exemplary embodiments are not limited thereto. For example, the window WIN and the anti-reflective layer RPL, the anti-reflective layer RPL and the input sensing unit ISP, the display panel DP and the protective layer PL, and the protective layer PL and the support unit SUP can be attached to each other in the same manner via the second adhesive layer AL2 to the fifth adhesive layer AL5.

[0112] Each of the second adhesive layers AL2 to the fifth adhesive layers AL5 may contain the same material as the first adhesive layer AL1 and have the same physical properties as the first adhesive layer AL1. Therefore, each of the second adhesive layers AL2 to the fifth adhesive layers AL5 may also have high elasticity, low strain, and high adhesion, just like the first adhesive layer AL1.

[0113] Reference Figure 5 and Figure 9 The display device DD can be folded inward relative to the folding axis FX. The display device DD can be folded from, for example... Figure 5 The flat first state shown is deformed as follows Figure 9 The second folded state shown can be transformed into the first state. This folding operation can be performed repeatedly.

[0114] The areas of the display device DD that overlap with the first support SUP1 and the areas of the display device DD that overlap with the second support SUP2 can each remain substantially flat. The folding area FA can bend from the boundary between the first support SUP1 and the folding area FA to the boundary between the second support SUP2 and the folding area FA.

[0115] However, this is merely an example. Exemplary embodiments are not limited to the curved areas. For example, the portions of the display device DD adjacent to the first support SUP1 and the portions of the display device DD adjacent to the second support SUP2 may remain substantially flat, while the remaining portions may be bent, causing the display device DD to be folded. For the folding operation of the display device DD, each of the window protective layer WPL, window WIN, anti-reflective layer RPL, input sensing unit ISP, display panel DP, protective layer PL, and first adhesive layers AL1 to fifth adhesive layers AL5 may generally be flexible.

[0116] When folding operations are repeatedly performed, the stress generated in the folded area FA can affect the first adhesive layer AL1 to the fifth adhesive layer AL5. However, since each of the first adhesive layer AL1 to the fifth adhesive layer AL5 has high elasticity, low strain, and generally high adhesion, the elasticity and adhesion of each of the first adhesive layer AL1 to the fifth adhesive layer AL5 can be maintained, and the strain of each of the first adhesive layer AL1 to the fifth adhesive layer AL5 can be reduced.

[0117] In the following text, test results of the elastic modulus, strain, and adhesive force of the first adhesive layer AL1 based on various temperatures according to an exemplary embodiment will be described in a table. Furthermore, test results of the elastic modulus, strain, and adhesive force of a comparative adhesive layer used for comparison with the first adhesive layer AL1 will be described in a table in conjunction with the test results of the first adhesive layer AL1.

[0118] As described herein, the storage modulus G' and loss modulus G″ of the adhesive layer correspond to values ​​measured by a rheometer (manufactured by TA Instruments, a subsidiary of Waters Corporation in Milford, Massachusetts). Samples for measuring the storage modulus G' are prepared by machining the adhesive layer into a disk shape having a diameter of approximately 8 mm and a thickness of approximately 800 μm. For example, an adhesive layer product used in a display device DD can be machined to have a diameter of approximately 8 mm and a thickness of approximately 800 μm and used as a test sample.

[0119] However, this is merely an example. The adhesive layer attached to the display device DD can be separated from the display device DD and used as a test sample. For example, when a predetermined time has elapsed since the portion of the display device DD with the adhesive layer was inserted into an organic solvent, the adhesive layer can be swollen and expanded by the organic solvent. The expanded adhesive layer can be removed from the display device DD and then processed and used as a test sample.

[0120] Storage modulus G' and loss modulus G″ can be measured at a temperature increase rate of about 10 °C / min, with a frequency of about 1 Hz and an axial force of about 1.0 N applied from the rheometer and the adhesive layer maintaining a strain of about 1%.

[0121] In the following text, the exemplary embodiments in the table are test results of a first adhesive layer AL1 made according to the principles and exemplary embodiments of the present invention, and the comparative examples are test results of a comparative adhesive layer. The comparative adhesive layer may be a substantially existing adhesive layer.

[0122] Table 1 shows the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the first adhesive layer AL1 at a temperature of approximately -20°C, as well as the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the adhesive layers.

[0123] Storage modulus G' represents the degree of elasticity of the adhesive layer, and loss modulus G″ represents the degree of fluidity of the adhesive layer. The loss tangent (tanδ) can be defined as the value obtained by dividing the loss modulus G″ by the storage modulus G'. A temperature of approximately -20°C can be defined as low temperature.

[0124] Table 1

[0125]

[0126] Referring to the results in Table 1, at a temperature of approximately -20°C, the first adhesive layer AL1 can have a storage modulus G' of approximately 0.1463 MPa to approximately 0.1994 MPa, a loss modulus G″ of approximately 0.1458 MPa to approximately 0.2071 MPa, and a loss tangent (tanδ) of approximately 0.9885 to approximately 1.0519. At a temperature of approximately -20°C, the first adhesive layer AL1 can have a storage modulus G' larger than that of the comparative adhesive layer.

[0127] When an adhesive layer is frozen and cured at low temperatures, its fluidity may be lost. In this case, the adhesive layer may lose its adhesiveness and may peel off from the attached object. For example, when the first adhesive layer AL1 is frozen and cured, the first adhesive layer AL1 may lose its adhesiveness, and in this case, the first adhesive layer AL1 may peel off from the window WIN and the window protective layer WPL.

[0128] When the adhesive layer does not freeze at low temperatures, its adhesive properties can be maintained. For example, at low temperatures, since the loss modulus G″ is relatively greater than the storage modulus G', the fluidity of the adhesive layer can increase to further adequately maintain its adhesive properties. Therefore, at low temperatures, the adhesive layer can have better adhesive properties as the value of the loss tangent (tanδ), defined as the value obtained by dividing the loss modulus G″ by the storage modulus G', increases.

[0129] At a temperature of approximately -20°C, the first adhesive layer AL1 can have a larger loss tangent (tanδ) than the comparative adhesive layer. Therefore, the first adhesive layer AL1 can have greater adhesion than the comparative adhesive layer at a temperature of approximately -20°C.

[0130] Table 2 shows the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the first adhesive layer AL1 at approximately 2°C, and compares the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the adhesive layers. The temperature of approximately 2°C can be defined as low temperature.

[0131] Table 2

[0132]

[0133]

[0134] Referring to the results in Table 2, the first adhesive layer AL1 can have a storage modulus G' of about 0.0490 MPa to about 0.0629 MPa, a loss modulus G″ of about 0.0229 MPa to about 0.0318 MPa, and a loss tangent (tanδ) of about 0.4673 to about 0.5056 at a temperature of about 2°C. At a temperature of about 2°C, the first adhesive layer AL1 can have a storage modulus G' larger than that of the comparative adhesive layer. At a temperature of about 2°C, the first adhesive layer AL1 can have a loss tangent (tanδ) larger than that of the comparative adhesive layer.

[0135] Table 3 shows the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the first adhesive layer AL1 at a temperature of approximately 25°C, and compares the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the adhesive layer. The temperature of approximately 25°C can be defined as room temperature.

[0136] Table 3

[0137]

[0138]

[0139] Referring to the results in Table 3, the first adhesive layer AL1 can have a storage modulus G' of about 0.0317 MPa to about 0.0348 MPa, a loss modulus G″ of about 0.0108 MPa to about 0.0120 MPa, and a loss tangent (tanδ) of about 0.3359 to about 0.3480 at a temperature of about 25°C. At a temperature of about 25°C, the first adhesive layer AL1 can have a storage modulus G' that is larger than that of the comparative adhesive layer.

[0140] As the temperature increases to higher temperatures, the elastic modulus of the adhesive layer can decrease. At both room temperature and high temperatures, an increase in the elastic modulus of the adhesive layer is significant. For example, at both room temperature and high temperatures, the elasticity of the adhesive layer can be further adequately maintained because the storage modulus G' is relatively greater than the loss modulus G″. Therefore, at both room temperature and high temperatures, the adhesive layer can exhibit better elasticity as the value of the loss tangent (tanδ), defined as the value obtained by dividing the loss modulus G″ by the storage modulus G', decreases.

[0141] The first adhesive layer AL1 can have a smaller loss tangent (tanδ) than the comparative adhesive layer at a temperature of about 25°C. Therefore, the first adhesive layer AL1 can have greater elasticity than the comparative adhesive layer at a temperature of about 25°C.

[0142] Table 4 shows the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the first adhesive layer AL1 at approximately 60°C, and compares the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the adhesive layers. The temperature of 60°C can be defined as high temperature.

[0143] Table 4

[0144]

[0145]

[0146] Referring to the results in Table 4, the first adhesive layer AL1 can have a storage modulus G' of about 0.0181 MPa to about 0.0243 MPa, a loss modulus G″ of about 0.0073 MPa to about 0.0102 MPa, and a loss tangent (tanδ) of about 0.4033 to about 0.4309 at a temperature of about 60°C. At a temperature of about 60°C, the first adhesive layer AL1 can have a storage modulus G' that is larger than that of the comparative adhesive layer.

[0147] The first adhesive layer AL1 can have a smaller loss tangent (tanδ) than the comparative adhesive layer at a temperature of about 60°C. Therefore, the first adhesive layer AL1 can have greater elasticity than the comparative adhesive layer at a temperature of about 60°C.

[0148] Table 5 presents the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the first adhesive layer AL1 at approximately 85°C, and compares the test results of the storage modulus G', loss modulus G″, and loss tangent (tanδ) of the adhesive layer. The temperature of approximately 85°C can be defined as high temperature.

[0149] Table 5

[0150]

[0151] Referring to the results in Table 5, the first adhesive layer AL1 can have a storage modulus G' of about 0.0137 MPa to about 0.0215 MPa, a loss modulus G″ of about 0.0058 MPa to about 0.0095 MPa, and a loss tangent (tanδ) of about 0.4173 to about 0.4455 at a temperature of about 85°C.

[0152] The first adhesive layer AL1 can have a smaller loss tangent (tanδ) than the comparative adhesive layer at a temperature of about 85°C. Therefore, the first adhesive layer AL1 can have greater elasticity than the comparative adhesive layer at a high temperature of about 85°C.

[0153] Therefore, compared to the elasticity and adhesion of the comparative adhesive layers, the first adhesive layer AL1 can exhibit higher elasticity and higher adhesion. In the tests shown in Tables 1 to 5, the glass transition temperature of the first adhesive layer AL1 was measured in the range of approximately -37.41°C to approximately 37.86°C.

[0154] As described herein, the creep value and residual strain of the adhesive layer correspond to values ​​measured by a rheometer as described above. Samples for measuring creep value and residual strain were prepared by forming the adhesive layer into a disk shape having a diameter of approximately 8 mm and a thickness of approximately 800 μm.

[0155] When a stress of approximately 2000 Pa is applied to the adhesive layer for approximately 10 minutes, the creep value is measured as the strain of the adhesive layer. After approximately 10 minutes following the removal of the applied stress, the residual strain is measured as the strain of the adhesive layer. The residual strain can be defined as the strain of the adhesive layer remaining after the stress has been removed and the adhesive layer has recovered for approximately 10 minutes. As each of the creep value and residual strain decreases, the strain of the adhesive layer, depending on the stress or pressure, decreases.

[0156] Table 6 shows the test results of creep value and residual strain of the first adhesive layer AL1 at a temperature of about 60°C, and compares the test results of creep value and residual strain of the adhesive layer.

[0157] Table 6

[0158]

[0159] Referring to the results in Table 6, when a stress of approximately 2000 Pa is maintained at a temperature of approximately 60°C for approximately 10 minutes, the first adhesive layer AL1 can have a creep value of approximately 52.3894% to approximately 59.9129%. Furthermore, after approximately 10 minutes following the removal of the applied stress at approximately 60°C, the first adhesive layer AL1 can have a residual strain of approximately 6.3912% to approximately 8.5546%.

[0160] The first adhesive layer AL1 has a smaller creep value and residual strain than the comparative adhesive layer at a temperature of about 60°C. Based on the creep value and residual strain of the first adhesive layer AL1 at a temperature of about 60°C, the first adhesive layer AL1 has a recovery rate of about 85.7216% to about 87.8005%.

[0161] Table 7 shows the test results of creep value and residual strain of the first adhesive layer AL1 at a temperature of about 25°C, and compares the test results of creep value and residual strain of the adhesive layer.

[0162] Table 7

[0163]

[0164] Referring to the results in Table 7, when a stress of approximately 2000 Pa is maintained at a temperature of approximately 25°C for approximately 10 minutes, the first adhesive layer AL1 can have a creep value of approximately 38.1876% to approximately 40.4371%. Furthermore, after approximately 10 minutes following the removal of the applied stress at approximately 25°C, the first adhesive layer AL1 can have a residual strain of approximately 7.0426% to approximately 8.0211%.

[0165] The first adhesive layer AL1 can have a smaller creep value and residual strain than the comparative adhesive layer at a temperature of about 25°C. Based on the creep value and residual strain of the first adhesive layer AL1 at a temperature of about 25°C, the first adhesive layer AL1 has a recovery rate of about 79.7425% to about 81.6250%.

[0166] Since the first adhesive layer AL1 has a smaller creep value and residual strain than the comparative adhesive layer, the strain of the first adhesive layer AL1 under stress or pressure can be further reduced compared to the comparative adhesive layer.

[0167] Figure 10 It is used for measurement Figure 5 A perspective view of the method for applying adhesive force to the first adhesive layer.

[0168] Reference Figure 10 A glass glass layer (GLS) can be fabricated as a base layer, and a first adhesive layer (AL1) can be disposed on the glass GLS. A film (FLM) can be disposed on the first adhesive layer (AL1). The film (FLM) can be attached to the glass GLS through the first adhesive layer (AL1). The glass GLS can correspond to a window (WIN), and the film (FLM) can correspond to a window protective layer (WPL).

[0169] The adhesive strength of the first adhesive layer AL1 was measured when the film FLM was attached to the glass GLS for approximately 30 minutes and then peeled off from the glass GLS after approximately 30 minutes. The adhesive strength of the adhesive layers was compared and measured in the same manner.

[0170] Figure 8 The test results of the adhesive strength of the first adhesive layer AL1 and the adhesive strength of the comparative adhesive layers are shown under temperature conditions of about 25°C and about 80°C.

[0171] Table 8

[0172]

[0173] Referring to the results in Table 8, at a temperature of approximately 25°C, the adhesive force of the first adhesive layer AL1 relative to the glass GLS (e.g., window WIN) is approximately 810 ± 25 gf / in. At a temperature of approximately 80°C, the adhesive force of the first adhesive layer AL1 relative to the glass GLS is approximately 256 ± 17 gf / in. The first adhesive layer AL1 can have a greater adhesive force than the comparative adhesive layers. Therefore, the first adhesive layer AL1 can have high adhesion.

[0174] Figure 11 The graph depicts the average values ​​of the storage modulus and loss modulus of the first adhesive layer manufactured according to the principle of the present invention at temperatures of approximately 2°C and approximately 25°C, and compares the average values ​​of the storage modulus and loss modulus of the adhesive layer. Figure 12The graph depicts the average value of the loss tangent of the first adhesive layer and the average value of the loss tangent of the comparative adhesive layers, which were produced according to the principle of the present invention at temperatures of approximately 2°C and approximately 25°C. Figure 13 It is a graphical depiction of the average creep value of the first adhesive layer made according to the principle of the present invention at temperatures of about 25°C and about 60°C, and the average creep value of the comparative adhesive layers.

[0175] For example, Figure 11 and Figure 12 The average values ​​of the data for the corresponding exemplary and comparative examples in Tables 2 and 3 are plotted. Similarly, Figure 13 The average values ​​of the data for the corresponding exemplary and comparative examples in Tables 6 and 7 are plotted. Figure 11 In this context, both the energy storage modulus and the loss modulus are expressed to three decimal places. Figure 12 and Figure 13 For example, the loss tangent is expressed to three decimal places, and the creep value is expressed to one decimal place.

[0176] Reference Figure 11 Based on the average values ​​of energy storage modulus and loss modulus, the first adhesive layer AL1 can have a larger energy storage modulus and loss modulus than the comparative adhesive layer at temperatures of about 2°C and about 25°C.

[0177] Reference Figure 12 Based on the average value of the loss tangent, the first adhesive layer AL1 can have a larger loss tangent than the comparative adhesive layer at a temperature of about 2°C, and a smaller loss tangent than the comparative adhesive layer at a temperature of about 25°C.

[0178] Reference Figure 13 Based on the average creep value, the first adhesive layer AL1 can have a smaller creep value than the comparative adhesive layer at temperatures of about 25°C and about 60°C.

[0179] Based on the aforementioned significant and unexpected test results, the first adhesive layer AL1 exhibits high elasticity, low strain, and high adhesion. Therefore, during the pressing and folding processes of the display device DD, the elasticity and adhesion of the first adhesive layer AL1 can be easily maintained, and the strain of the first adhesive layer AL1 can be reduced.

[0180] While certain exemplary embodiments and implementations have been described herein, other embodiments and variations will become apparent from this description. Accordingly, the inventive concept is not limited to these embodiments, but is limited to the broader scope of the appended claims and various obvious variations and equivalent arrangements that will be apparent to those skilled in the art.

Claims

1. A display device, comprising: Display panel; A window, which is arranged on the display panel; A window protective layer, wherein the window protective layer is disposed on the window; as well as A first adhesive layer is disposed between the window and the window protective layer. Specifically, when a stress of 2000 Pa is applied to the first adhesive layer for 10 minutes, the first adhesive layer exhibits a creep value of 38.1876% to 40.4371% at a temperature of 25°C. When a frequency of 1 Hz and an axial force of 1.0 N are applied and the first adhesive layer maintains a strain of 1%, the first adhesive layer has a storage modulus of 0.0317 MPa to 0.0348 MPa, a loss modulus of 0.0108 MPa to 0.0120 MPa, and a loss tangent of 0.3359 to 0.3480 at a temperature of 25°C. The loss tangent is defined as the loss modulus divided by the energy storage modulus.

2. The display device as claimed in claim 1, wherein, The first adhesive layer has a storage modulus of 0.1463 MPa to 0.1994 MPa, a loss modulus of 0.1458 MPa to 0.2071 MPa, and a loss tangent of 0.9885 to 1.0519 at a temperature of -20°C.

3. The display device as claimed in claim 1, wherein, The first adhesive layer has a storage modulus of 0.0490 MPa to 0.0629 MPa, a loss modulus of 0.0229 MPa to 0.0318 MPa, and a loss tangent of 0.4673 to 0.5056 at a temperature of 2°C.

4. The display device as claimed in claim 1, wherein, The first adhesive layer has a storage modulus of 0.0181 MPa to 0.0243 MPa, a loss modulus of 0.0073 MPa to 0.0102 MPa, and a loss tangent of 0.4033 to 0.4309 at a temperature of 60°C.

5. The display device as claimed in claim 1, wherein, The first adhesive layer has a storage modulus of 0.0137 MPa to 0.0215 MPa, a loss modulus of 0.0058 MPa to 0.0095 MPa, and a loss tangent of 0.4173 to 0.4455 at a temperature of 85°C.

6. The display device as claimed in claim 1, wherein, Ten minutes after the stress applied to the first adhesive layer is removed, the first adhesive layer has a residual strain of 7.0426% to 8.0211% at a temperature of 25°C.

7. The display device as claimed in claim 1, wherein, When a stress of 2000 Pa is applied to the first adhesive layer for 10 minutes, the first adhesive layer has a creep value of 52.3894% to 59.9129% at a temperature of 60°C.

8. The display device as claimed in claim 7, wherein, Ten minutes after the stress applied to the first adhesive layer is removed, the first adhesive layer has a residual strain of 6.3912% to 8.5546% at a temperature of 60°C.

9. The display device as claimed in claim 1, wherein, The first adhesive layer has a thickness of 10 μm to 50 μm.

10. The display device as claimed in claim 1, wherein, The first adhesive layer comprises silicone resin, acrylic resin or urethane resin.

11. The display device as claimed in claim 1, wherein, The window protective layer comprises at least one polymer resin selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, polystyrene, polyvinyl chloride, polyethersulfone, polypropylene, polyamide, modified polyphenylene ether, polyoxymethylene, polysulfone, polyphenylene sulfide, polyimide, polyethyleneimine, polyetheretherketone, polyamide-imide, polyarylate, and thermoplastic polyurethane.

12. The display device of claim 1, further comprising: An input sensor is arranged on the display panel; An anti-reflective layer is disposed between the input sensor and the window; A protective layer is disposed beneath the display panel; A support member, the support member being disposed beneath the protective layer; A second adhesive layer is disposed between the window and the anti-reflective layer; A third adhesive layer is disposed between the anti-reflective layer and the input sensor; A fourth adhesive layer is disposed between the display panel and the protective layer; as well as A fifth adhesive layer is disposed between the protective layer and the support member. At least one of the second adhesive layer, the third adhesive layer, the fourth adhesive layer, and the fifth adhesive layer has the same physical properties as the first adhesive layer.

13. The display device as claimed in claim 1, wherein, The window includes glass.

14. The display device as claimed in claim 13, wherein, The adhesive force of the first adhesive layer relative to the window is 810±25 gf / in at a temperature of 25°C, and The adhesive force is the peel force value when the window protective layer is attached to the window through the first adhesive layer and peeled off from the window at a 90-degree angle after 30 minutes.

15. The display device as claimed in claim 14, wherein, The adhesive force of the first adhesive layer relative to the window is 256±17 gf / in at a temperature of 80°C, and The adhesive force is the peel force value when the window protective layer is attached to the window through the first adhesive layer and peeled off from the window after 30 minutes.

16. The display device as claimed in claim 1, wherein, At least one of the display panel and the window protective layer is folded inward or outward relative to the folding axis.

17. A display device, comprising: Display panel; A window, which is arranged on the display panel; A window protective layer, wherein the window protective layer is disposed on the window; as well as An adhesive layer is disposed between the window and the window protective layer. Wherein, the adhesive force of the adhesive layer relative to the window is 810±25 gf / in at a temperature of 25°C, and the adhesive force of the adhesive layer relative to the window is 256±17 gf / in at a temperature of 80°C; and The adhesive force is the peel force value when the window protective layer is attached to the window through the adhesive layer and peeled off from the window at a 90-degree angle after 30 minutes.

18. The display device as claimed in claim 17, wherein, When a stress of 2000 Pa is applied to the adhesive layer for 10 minutes, the adhesive layer exhibits a creep value of 38.3271% to 40.4371% at a temperature of 25°C. When a frequency of 1 Hz and an axial force of 1.0 N are applied and the adhesive layer maintains a strain of 1%, the adhesive layer has a storage modulus of 0.0317 MPa to 0.0348 MPa and a loss modulus of 0.0108 MPa to 0.0120 MPa at a temperature of 25°C.

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