Display device and window module

Abstract

A display device includes: a display module foldable with respect to a folding axis extending in a direction; and a window disposed on the display module and including a folded portion and a non-folded portion, the folded portion being folded with respect to the folding axis. The folding portion includes a first folding surface adjacent to the display module and a second folding surface opposite and spaced apart from the first folding surface. A plurality of first slots may be defined in the first folding surface, a plurality of second slots may be defined in the second folding surface, and a ratio of a Young's modulus of the folded portion to a Young's modulus of the non-folded portion may be in a range of about 30 / 70000 to about 2000 / 70000.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the priority of Korean Patent Application No. 10-2023-0078171 filed in the Korean Intellectual Property Office on June 19, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a window module including a window in which a groove may be defined, and a display device including the window module. Background Art

[0004] The display device displays various images through a display screen to provide information to a user. Generally speaking, the display device displays information in an allocated area of ​​the display screen. In recent years, flexible display devices including foldable flexible display panels are being developed. Unlike rigid display devices, flexible display devices may be foldable, rollable, or bendable. Flexible display devices that can be converted into various shapes can be easily carried and can improve user convenience regardless of the original size of the display screen.

[0005] In the case where a structure for ensuring the flexibility of a flexible display device is applied to the flexible display device, the durability of the flexible display device against impact may be weakened. In the case where a structure for strengthening the durability of a flexible display device against impact is applied to the flexible display device, the flexibility of the flexible display device may be deteriorated. Summary of the invention

[0006] The present disclosure provides a foldable window module with improved durability.

[0007] The present disclosure provides a display device including a foldable window module having improved durability.

[0008] An embodiment of the inventive concept provides a display device, which may include a display module that is foldable relative to a folding axis extending in a first direction and a window disposed on the display module and including a folding portion and a non-folding portion. The folding portion may include: a first folding surface adjacent to the display module, the first folding surface may include a plurality of first grooves defined in the first folding surface, and a second folding surface opposite to the first folding surface and spaced apart from the first folding surface by a window thickness, the second folding surface may include a plurality of second grooves defined in the second folding surface. The folding portion may be foldable relative to the folding axis, and a ratio of a Young's modulus of the folding portion to a Young's modulus of the non-folding portion may be in a range of about 30 / 70000 to about 2000 / 70000.

[0009] The thickness of the window may be in the range of about 100 μm to about 175 μm, and the radius of curvature of the folded portion after folding with respect to the folding axis may be in the range of about 1.0 mm to about 2.0 mm.

[0010] The thickness of the window may be about 100 μm.

[0011] The window may have a thickness of about 125 μm, a radius of curvature may be in the range of about 1.0 mm to about 1.5 mm, and a ratio of the Young's modulus of the folded portion to the Young's modulus of the non-folded portion may be in the range of about 50 / 70000 to about 2000 / 70000.

[0012] The ratio of the Young's modulus of the folded portion to the Young's modulus of the non-folded portion may be in the range of about 75 / 70000 to about 2000 / 70000. The window may have a thickness of about 150 μm and a radius of curvature of about 1.0 mm, or a thickness of about 125 μm and a radius of curvature of about 2.0 mm.

[0013] The ratio of the Young's modulus of the folded portion to the Young's modulus of the non-folded portion may be in the range of about 100 / 70000 to about 2000 / 70000. The thickness of the window may be about 175 μm and the radius of curvature may be about 1.0 mm, or the thickness of the window may be in the range of about 150 μm to about 175 μm and the radius of curvature may be in the range of about 1.5 mm to about 2.0 mm.

[0014] The Young's modulus of the unfolded portion may be in a range of about 65 GPa to about 75 GPa.

[0015] The plurality of first grooves and the plurality of second grooves may be arranged in an alternating manner in a second direction intersecting the first direction in a plan view.

[0016] The window includes a plurality of first folded middle portions and a plurality of second folded middle portions, the plurality of first folded middle portions may respectively overlap with the plurality of first grooves in a plan view, the plurality of second folded middle portions may respectively overlap with the plurality of second grooves in a plan view, and the thickness of each of the plurality of first folded middle portions and the thickness of each of the plurality of second folded middle portions may be in the range of about 35 μm to about 40 μm.

[0017] A thickness of each of the plurality of first folded middle portions and a thickness of each of the plurality of second folded middle portions may be substantially equal to each other.

[0018] A width of each of the plurality of first grooves and each of the plurality of second grooves in a second direction intersecting the first direction may be in a range of about 80 μm to about 100 μm.

[0019] A width of a sidewall portion of the folded portion disposed between one of the plurality of first grooves and one of the plurality of second grooves adjacent to the one of the plurality of first grooves may be in a range of about 25 μm to about 35 μm.

[0020] Each of a distance between two of the plurality of first grooves adjacent to each other and a distance between two of the plurality of second grooves adjacent to each other may be in a range of about 120 μm to about 150 μm.

[0021] The display device may further include a protective film disposed on the window.

[0022] The window may comprise a glass material.

[0023] The plurality of first grooves and the plurality of second grooves may not overlap with the non-folded portion in a plan view.

[0024] An embodiment of the inventive concept provides a window module, which may include a window including a folding portion and a non-folding portion and a protective film disposed on the window. The folding portion may include: a first folding surface including a plurality of first grooves defined in the first folding surface, and a second folding surface including a plurality of second grooves defined in the second folding surface, the second folding surface may be opposite to the first folding surface and spaced apart from the first folding surface by the thickness of the window. The folding portion may be folded relative to a folding axis extending in a first direction. The ratio of the Young's modulus of the folding portion to the Young's modulus of the non-folding portion may be in the range of about 30 / 70000 to about 2000 / 70000, and the shortest distance between the folding axis and the upper surface of the protective film may be in the range of about 1.0 mm to about 2.0 mm.

[0025] The window module may further include an adhesive layer disposed between the window and the protective film.

[0026] The plurality of first grooves and the plurality of second grooves may be arranged in an alternating manner in a second direction intersecting the first direction in a plan view.

[0027] The plurality of first grooves and the plurality of second grooves may not overlap with the non-folded portion in a plan view.

[0028] According to the above, since the groove may be defined in both the upper and lower surfaces of the window, the window module may be folded, and the durability of the window module may be improved.

[0029] According to the above, a display device including a window module including a window provided with grooves defined in both upper and lower surfaces of the window may be foldable and may have improved durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other advantages of the present disclosure will become readily apparent by referring to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0031] Figure 1 is a perspective view of a display device according to an embodiment of the present disclosure;

[0032] Figure 2A is a perspective view of an inwardly folded (inwardly folded) display device according to an embodiment of the present disclosure;

[0033] Figure 2B is a perspective view of an outwardly folded (outwardly folded) display device according to an embodiment of the present disclosure;

[0034] Figure 3 is a schematic cross-sectional view of a display device according to an embodiment of the present disclosure;

[0035] Figure 4 is a schematic cross-sectional view of a display device in a folded state according to an embodiment of the present disclosure; and

[0036] Figure 5 for Figure 3 An enlarged schematic cross-sectional view of the window shown in FIG. DETAILED DESCRIPTION

[0037] In the following description, for the purpose of explanation, many specific details are stated in order to provide a thorough understanding of various embodiments or implementations of the present invention. As used herein, "embodiment" and "implementation" are interchangeable words, which are non-limiting examples of the devices or methods disclosed herein. However, it is apparent that various embodiments may be practiced without these specific details or with one or more equivalent arrangements. Here, various embodiments do not have to be exclusive and do not limit the present disclosure. For example, a specific shape, configuration, and characteristic in one embodiment may be used or implemented in another embodiment.

[0038] Unless otherwise indicated, the illustrated embodiments should be understood to provide features of the present invention. Therefore, unless otherwise indicated, the features, components, modules, layers, films, panels, regions and / or aspects of the various embodiments (hereinafter individually or collectively referred to as "elements") can be combined, separated, interchanged and / or rearranged in other ways without departing from the concept of the present invention.

[0039] Cross hatching and / or shading are often used in the accompanying drawings to illustrate the boundaries between adjacent elements. As such, the presence or absence of cross hatching or shading does not convey or indicate any preference or requirement for a particular material, material property, dimension, ratio, commonality between the illustrated elements, and / or any other characteristics, attributes, properties, etc. of the elements, unless specifically noted. Further, in the accompanying drawings, the size and relative size of the elements may be magnified for the purpose of clarity and / or description. When an embodiment may be implemented differently, a specific process sequence may be performed differently from the described sequence. For example, two consecutive described processes may be performed substantially simultaneously or in an order opposite to the described sequence. Moreover, the same reference numerals and / or reference characters represent the same elements.

[0040] When an element or layer is referred to as being "on", "connected to" or "coupled to" another element or layer, it may be directly on, connected to or coupled to another element or layer, or there may be intervening elements or layers. However, when an element or layer is referred to as being "directly on", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. For this purpose, the term "connected" may refer to physical, electrical and / or fluid connections, with or without intervening elements. Further, the X-axis, Y-axis and Z-axis (or DR1, DR2 and DR3) are not limited to three axes of a rectangular coordinate system, such as the x, y and z axes, and may be interpreted in a broader sense. For example, the X-axis, Y-axis and Z-axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purposes of this disclosure, "at least one of A and B" may be interpreted as only A, only B, or any combination of A and B. Moreover, “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 any combination of only X, only Y, only Z, or two or more of X, Y, and Z. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0041] 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 element. Therefore, the first element discussed below may be referred to as the second element without departing from the teachings of the present disclosure.

[0042] Spatially relative terms, such as "below," "beneath," "below," "above," "above," "higher," and "side" (e.g., as in "sidewall"), etc., may be used herein for descriptive purposes, and thereby describe the relationship of one element to another element as illustrated in the accompanying drawings. Spatially relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, elements or features described as being "below" or "beneath" other elements or features will be oriented "above" the other elements or features. Thus, the term "below" may encompass both above and below orientations. 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.

[0043] The terms used in this article are for the purpose of describing a specific embodiment, and are not intended to be restrictive. As used in this article, unless the context clearly indicates otherwise, the singular forms "a", "an" and "said" are intended to also include plural forms. Moreover, the terms "including" and / or "comprising" indicate the existence of the narrated features, integers, steps, operations, elements, parts and / or its groups when used in this specification, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, parts and / or its groups. It should also be noted that, as used in this article, the terms "substantially", "about" and other similar terms are used as approximate terms rather than degree terms, and, for this reason, are used to illustrate the inherent deviations of the values ​​that will be recognized by those of ordinary skill in the art, measured, calculated and / or provided.

[0044] Various embodiments are described herein with reference to cross-sectional and / or exploded views that are schematic illustrations of embodiments and / or intermediate structures. As such, variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are expected. Thus, the embodiments disclosed herein should not necessarily be construed as limited to only the specific illustrated shapes of the regions, but rather include deviations in shapes resulting from, for example, manufacturing. In this manner, the regions illustrated in the drawings 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.

[0045] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0046] Figure 1 is a perspective view of a display device ED according to an embodiment of the present disclosure.

[0047] refer to Figure 1 , the display device ED can display the image IMG through the display surface DD-IS. Figure 1, a clock plug-in image, a search box image, and an application icon image are shown as images IMG. The display surface DD-IS may be substantially parallel to a plane defined by the first direction DR1 and the second direction DR2. The normal direction of the display surface DD-IS, that is, the thickness direction of the display device ED, may be indicated by a third direction DR3. The front (or upper) surface and the rear (or lower) surface of each member or each unit of the display device ED may be distinguished from each other with respect to the third direction DR3.

[0048] The display surface DD-IS may include a display area DD-DA in which an image IMG may be displayed and a non-display area DD-NDA defined adjacent to the display area DD-DA, and the image IMG may not be displayed through the non-display area DD-NDA. The display area DD-DA may have a quadrilateral shape. The non-display area DD-NDA may surround the display area DD-DA, however, the present disclosure may not be limited thereto or thereby. The shape of the display area DD-DA and the shape of the non-display area DD-NDA may be designed relative to each other. According to one embodiment, the non-display area DD-NDA may be omitted.

[0049] Figure 1 A portable electronic device is shown as a representative example of the display device ED, however, the present disclosure should not be limited thereto or thereby. The display device ED can be applied to large-sized electronic items such as televisions and monitors and small and medium-sized electronic items such as mobile phones, tablet computers, car navigation units, game units, and smart watches.

[0050] Figure 2A 4 is a perspective view of an inwardly foldable (inwardly foldable) display device ED according to an embodiment of the present disclosure. Figure 2B 4 is a perspective view of an outwardly foldable (outwardly foldable) display device ED according to an embodiment of the present disclosure.

[0051] refer to Figure 2A , the display device ED may include a plurality of areas defined according to its operation state. The display device ED may include a first non-folding area NFA1, a second non-folding area NFA2, and a folding area FA disposed between the first non-folding area NFA1 and the second non-folding area NFA2. The first non-folding area NFA1, the folding area FA, and the second non-folding area NFA2 may be arranged sequentially in the second direction DR2. The folding area FA may be folded based on the folding axis FX, and the folding area FA may be a region substantially formed with a curvature.

[0052] The display device ED may be folded inward (inwardly folded) to allow the display surface DD-IS corresponding to the first non-folding area NFA1 to face the display surface DD-IS corresponding to the second non-folding area NFA2.

[0053] refer to Figure 2B , the display device ED may be folded outward (outwardly folded) to allow the display surface DD-IS to be exposed to the outside. The folding axis FX may extend in the first direction DR1, and the folding axis FX may be a short axis of the display device ED.

[0054] Figure 3 is a schematic cross-sectional view of a display device ED according to an embodiment of the present disclosure. Figure 4 is a schematic cross-sectional view of a display device ED in a folded state according to an embodiment of the present disclosure. Figure 5 for Figure 3 An enlarged schematic cross-sectional view of the window WD is shown in FIG.

[0055] refer to Figure 3 , the display device ED may include a window module WDM, a display module DM, a lower protective film BPF, a protection panel PP, and a lower member BP. The window module WDM may include a protection film WPF, an adhesive layer AD, and a window WD. The display device ED may be a flexible display device ED, and therefore, each of the window module WDM, the display module DM, the lower protective film BPF, the protection panel PP, and the lower member BP may have flexibility.

[0056] The display module DM can be folded relative to a folding axis FX extending in a first direction DR1. The display module DM may include a first non-folding area NFA1, a second non-folding area NFA2 and a folding area FA. The display module DM may include a display panel, a sensing portion and an anti-reflection layer. According to one embodiment, at least one of the sensing portion and the anti-reflection layer may be omitted. As an example, the display module DM may include only a display panel. The display panel may be a light-emitting display panel, however, it should not be particularly limited. For example, the display panel may be an organic light-emitting display panel or a quantum dot light-emitting display panel. The light-emitting layer of the organic light-emitting display panel may include an organic light-emitting material. The light-emitting layer of the quantum dot light-emitting display panel may include quantum dots and / or quantum rods.

[0057] The lower protective film BPF may be disposed under the display module DM. The lower protective film BPF may prevent scratches from occurring on the rear surface of the display module DM during the manufacturing process of the display module DM. The lower protective film BPF may be a colored polyimide film. For example, the lower protective film BPF may be an opaque yellow film, however, it should not be particularly limited as long as the lower protective film BPF has flexibility and protects the lower portion of the display module DM.

[0058] The protection panel PP may be disposed under the lower protection film BPF. The lower member BP may be disposed under the protection panel PP. Since the protection panel PP and the lower member BP may be disposed under the lower protection film BPF, the impact resistance of the display device ED may be improved. The protection panel PP and the lower member BP may protect components disposed on the protection panel PP. The lower member BP may include a functional layer such as a buffer layer.

[0059] The protective film WPF may be referred to as a window protective film WPF. Since the protective film WPF may be disposed on (e.g., attached to) the window WD, the impact resistance of the display device ED may be improved. The protective film WPF may protect components disposed below the protective film WPF. A hard coating layer and an anti-fingerprint layer may be additionally provided to the protective film WPF to improve properties such as chemical resistance and wear resistance. The protective film WPF may include a transparent material.

[0060] The adhesive layer AD may be disposed between the protection film WPF and the window WD. The adhesive layer AD may be an optically transparent adhesive film, an optically transparent resin, or a pressure-sensitive adhesive film.

[0061] The window WD may be disposed between the adhesive layer AD and the display module DM. The window WD may protect the display module DM from external scratches and impacts. The window WD may include an optically transparent insulating material. As an example, the window WD may include a glass material, such as a thin film glass. The image generated by the display module DM may be provided to the user after passing through the window WD. The window WD may have a single-layer or multi-layer structure. As an example, the window WD may include at least one of a touch screen film and an optical film. The optical film may be, for example, a polarizing film, a diffusion film, and a protective film.

[0062] The window WD may be provided on the display module DM and may include a folding portion FP and a non-folding portion NFP folded along a folding axis FX. The folding portion FP may overlap with the folding area FA in a plan view. The non-folding portion NFP may include a first non-folding portion NFP1 and a second non-folding portion NFP2. When viewed in a plan view, the first non-folding portion NFP1 may overlap with the first non-folding area NFA1. When viewed in a plan view, the second non-folding portion NFP2 may overlap with the second non-folding area NFA2.

[0063] The folding portion FP of the window WD may include a first folding surface WFS1 and a second folding surface WFS2. The first folding surface WFS1 may be adjacent to the display module DM. The second folding surface WFS2 may be opposite to the first folding surface WFS1 and may be spaced apart from the first folding surface WFS1. A plurality of first grooves HM1 may be defined in the first folding surface WFS1, and a plurality of second grooves HM2 may be defined in the second folding surface WFS2. In the case of a plan view, the first grooves HM1 may be arranged alternately with the second grooves HM2 along the second direction DR2. In the case of a plan view, in the case of the first grooves HM1 and the second grooves HM2 being arranged alternately along the second direction DR2, the window WD may be folded inward (inward folding) or folded outward (outward folding) depending on its operation mode. In the case where a force is applied to the window WD and the window WD is folded inward (inward folding), the width of the second groove HM2 in the second direction DR2 may be reduced. In the case where a force is applied to the window WD and the window WD is folded outward (outward folding), the width of the first groove HM1 in the second direction DR2 may be reduced. When viewed in a plan view, the first groove HM1 and the second groove HM2 may not overlap with the non-folding portion NFP.

[0064] refer to Figure 3 and Figure 5 , the first width (or thickness) W1 may correspond to the distance between the first folding surface WFS1 and the second folding surface WFS2. The first width W1 may correspond to the thickness or maximum thickness of the window WD. The first width W1 may be in the range of about 100 μm to about 175 μm. As an example, the first width W1 may be selected from about 100 μm, about 125 μm, about 150 μm and about 175 μm, however, this may be just an example.

[0065] The second width W2 may correspond to the thickness W2 of the side wall portion SP of the folded portion FP between one of the first grooves HM1 and one of the second grooves HM2 adjacent to the one of the first grooves HM1. The second width W2 may correspond to the separation distance between the first grooves HM1 and the second grooves HM2 adjacent to each other. The second width W2 may be in the range of about 25 μm to about 35 μm. As an example, the second width W2 may be about 31 μm, however, this may be just an example. The ratio of the second width W2 to the first width W1 may be in the range of about 25 / 175 to about 35 / 100. As an example, the ratio of the second width W2 to the first width W1 may be selected from about 31 / 100, about 31 / 125, about 31 / 150 and about 31 / 175. In the case where the ratio of the second width W2 to the first width W1 is less than about 25 / 175, the second width W2 may become relatively thin compared to the first width W1, so when the user folds the display device ED or the window module WDM inward or outward, buckling may occur in the folded portion FP. In the case where the ratio of the second width W2 to the first width W1 is greater than about 35 / 100, the second width W2 may become relatively thick compared to the first width W1, so when the user folds the display device ED or the window module WDM inward or outward, the tensile strain of the folded portion FP may exceed about 2.5%, thereby causing cracks.

[0066] The third width W3 may correspond to the distance W3 between two first grooves HM1 adjacent to each other in the first groove HM1, and may correspond to the distance between two second grooves HM2 adjacent to each other in the second groove HM2. The distance W3 between the first grooves HM1 may correspond to the length of a portion of the first folding surface WFS1 between the first grooves HM1, and the distance W3 between the second grooves HM2 may correspond to the length of a portion of the second folding surface WFS2 between the second grooves HM2. The distance W3 between the first grooves HM1 may be the minimum distance between the first grooves HM1, and the distance W3 between the second grooves HM2 may be the minimum distance between the second grooves HM2. The third width W3 may be in the range of about 120 μm to about 150 μm. As an example, the third width W3 may be about 134 μm, however, this may be only an example. The ratio of the third width W3 to the first width W1 may be in the range of about 120 / 175 to about 150 / 100. As an example, a ratio of the third width W3 to the first width W1 may be selected from about 134 / 100, about 134 / 125, about 134 / 150, and about 134 / 175.

[0067] The fourth width W4 may correspond to the width W4 of each of the first groove HM1 and the second groove HM2 in the second direction DR2. The width W4 of the first groove HM1 may be the width W4 of the first groove HM1 in the first folding surface WFS1, and the width W4 of the second groove HM2 may be the width W4 of the second groove HM2 in the second folding surface WFS2. The width W4 of each of the first groove HM1 and the second groove HM2 in the second direction DR2 may correspond to the maximum width of the first groove HM1 and the second groove HM2. The fourth width W4 may be in the range of about 80 μm to about 100 μm. As an example, the fourth width W4 may be about 89 μm, however, this may be only an example. The ratio of the fourth width W4 to the first width W1 may be in the range of about 80 / 175 to about 1. As an example, the ratio of the fourth width W4 to the first width W1 may be selected from about 89 / 100, about 89 / 125, about 89 / 150, and about 89 / 175.

[0068] The fifth width W5 may correspond to the distance W5 between the first bottom surface B-HM1 and the first folding surface WFS1 defining the bottom of the first groove HM1, and may correspond to the distance W5 between the second bottom surface B-HM2 and the second folding surface WFS2 defining the bottom of the second groove HM2. The fifth width W5 may correspond to the depth of the first groove HM1 or the depth of the second groove HM2. The fifth width W5 may be in the range of about 60 μm to about 140 μm. As an example, the fifth width W5 may be selected from about 60 μm, about 65 μm, about 85 μm, about 90 μm, about 110 μm, and about 115 μm, however, this may be only an example. The ratio of the fifth width W5 to the first width W1 may be in the range of about 60 / 175 to about 140 / 100.

[0069] The window WD may include a plurality of first folded middle parts FBP1 and a plurality of second folded middle parts FBP2. When viewed in a plan view, the first folded middle parts FBP1 may overlap the first grooves HM1, respectively. When viewed in a plan view, the second folded middle parts FBP2 may overlap the second grooves HM2, respectively. The window WD may include a plurality of first bottom surfaces B-HM1 overlapping the first grooves HM1, respectively, when viewed in a plan view, and a plurality of second bottom surfaces B-HM2 overlapping the second grooves HM2, respectively, when viewed in a plan view. The sixth width W6 may correspond to the thickness of one of the first folded middle parts FBP1. The sixth width W6 may be the shortest distance between the first bottom surface B-HM1 and the second folding surface WFS2. The seventh width W7 may be the thickness of one of the second folded middle parts FBP2. The seventh width W7 may be the shortest distance between the second bottom surface B-HM2 and the first folding surface WFS1. The sixth width W6 may be different from the seventh width W7. Each of the sixth width W6 and the seventh width W7 may be in the range of about 35 μm to about 40 μm. As an example, the sixth width W6 may be about 35 μm or about 40 μm, however, this may be only an example. The sixth width W6 and the seventh width W7 may be substantially equal.

[0070] The ratio of the sixth width W6 to the first width W1 may be in the range of about 35 / 175 to about 40 / 100. The ratio of the seventh width W7 to the first width W1 may be in the range of about 35 / 175 to about 40 / 100. As an example, the ratio of the sixth width W6 to the first width W1 may be selected from about 35 / 100, about 35 / 125, about 35 / 150, and about 35 / 175. As an example, the ratio of the seventh width W7 to the first width W1 may be selected from about 40 / 100, about 40 / 125, about 40 / 150, and about 40 / 175. In the case where the ratio of the sixth width W6 to the first width W1 or the ratio of the seventh width W7 to the first width W1 is less than about 35 / 175, the sixth width W6 or the seventh width W7 may become relatively thin compared to the first width W1, and thus, in the case where the user folds the display device ED or the window module WDM inwardly or outwardly, buckling may occur in the folded portion FP. In the case where the ratio of the sixth width W6 to the first width W1 or the ratio of the seventh width W7 to the first width W1 is greater than about 40 / 100, the sixth width W6 or the seventh width W7 may become relatively thick compared to the first width W1, and thus, in the case where the user folds the display device ED or the window module WDM inwardly or outwardly, the tensile strain of the folded portion FP may exceed about 2.5%, thereby causing cracks.

[0071] Figure 4 The folded portion is shown along the folding axis FX. Figure 3The display device ED is shown in the inward folded state.

[0072] refer to Figure 3 and Figure 4 , the radius of curvature R of the display device ED may correspond to the shortest distance between the folding axis FX and the display device ED. The radius of curvature R may correspond to the shortest distance between the folding axis FX and the upper surface of the protective film WPF. The radius of curvature R (e.g., the radius of curvature of the folded portion FP after folding relative to the folding axis FX) may be in the range of about 1.0 mm to about 2.0 mm. As an example, the radius of curvature R may be selected from about 1.0 mm, about 1.5 mm, and about 2.0 mm, however, this may be just an example.

[0073] In the present disclosure, Young's modulus may be measured using a universal testing machine (UTM), which may be the LF+ series from Lloyd Instruments and will be referred to as the universal testing machine hereinafter.

[0074] In the window WD, a ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP may be in a range of about 30 / 70000 to about 2000 / 70000.

[0075] According to the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 and the curvature radius R of the display device ED, the following Table 1 shows the ratio of the Young's modulus of the folding part FP to the Young's modulus of the non-folding part NFP that can be allowed. The expression "allowable" used in this article means that no bending, buckling or splitting occurs in the folding part FP when the display device ED or the window module WDM is folded. The ratio of the Young's modulus of the folding part FP to the Young's modulus of the non-folding part NFP can be controlled by changing the first width W1 to the sixth width W6. As an example, when the second width W2 and the sixth width W6 are reduced, the ratio of the Young's modulus of the folding part FP to the Young's modulus of the non-folding part NFP can be reduced. The Young's modulus of the non-folding part NFP of the window WD (which can be measured using a universal testing machine at room temperature of about 25°C) can be in the range of about 65GPa to about 75GPa. As an example, the Young's modulus of the non-folding part NFP can be about 70GPa, however, this can only be an example.

[0076] Table 1

[0077]

[0078]

[0079] Referring to Table 1, in the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 100 μm and the radius of curvature R is in the range of about 1.0 mm to about 2.0 mm, the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP may be in the range of about 30 / 70000 to about 2000 / 70000. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 100 μm, the radius of curvature R is in the range of about 1.0 mm to about 2.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is less than about 30 / 70000, buckling may occur in the folded portion FP, and thus an irreversible change in physical properties may occur due to the buckling. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 100 μm, the radius of curvature R is in the range of about 1.0 mm to about 2.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is greater than about 2000 / 70000, the tensile strain may exceed about 2.5%, and thus cracks may occur in the folded portion FP. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 125 μm and the radius of curvature R is in the range of about 1.0 mm to about 1.5 mm, the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP may be in the range of about 50 / 70000 to about 2000 / 70000. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 125 μm, the radius of curvature R is in the range of about 1.0 mm to about 1.5 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is less than about 50 / 70000, buckling may occur in the folded portion FP, and thus an irreversible change in physical properties may occur due to the buckling. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 125 μm, the radius of curvature R is in the range of about 1.0 mm to about 1.5 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is greater than about 2000 / 70000, tensile strain may exceed about 2.5%, and thus cracks may occur in the folded portion FP.

[0080] In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 150 μm and the radius of curvature R is about 1.0 mm, the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP may be in the range of about 75 / 70000 to about 2000 / 70000. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 150 μm, the radius of curvature R is about 1.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is less than about 75 / 70000, buckling may occur in the folded portion FP, and thus an irreversible change in physical properties may occur. When the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is approximately 150 μm, the curvature radius R is approximately 1.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is greater than approximately 2000 / 70000, the tensile strain may exceed approximately 2.5%, and thus cracks may occur in the folded portion FP.

[0081] In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 125 μm and the radius of curvature R is about 2.0 mm, the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP may be in the range of about 75 / 70000 to about 2000 / 70000. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 125 μm, the radius of curvature R is about 2.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is less than about 75 / 70000, buckling may occur in the folded portion FP, and thus an irreversible change in physical properties may occur. When the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is approximately 125 μm, the curvature radius R is approximately 2.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is greater than approximately 2000 / 70000, the tensile strain may exceed approximately 2.5%, and thus cracks may occur in the folded portion FP.

[0082] When the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is in the range of about 150 μm to about 175 μm and the radius of curvature R is in the range of about 1.5 mm to about 2.0 mm, the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP may be in the range of about 100 / 70000 to about 2000 / 70000. When the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is in the range of about 150 μm to about 175 μm, the radius of curvature R is in the range of about 1.5 mm to about 2.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is less than about 100 / 70000, buckling may occur in the folded portion FP, and thus an irreversible change in physical properties may occur. When the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is in the range of about 150 μm to about 175 μm, the radius of curvature R is in the range of about 1.5 mm to about 2.0 mm, and the ratio of the Young's modulus of the folding portion FP to the Young's modulus of the non-folding portion NFP is greater than about 2000 / 70000, the tensile strain may exceed about 2.5%, and thus cracks may occur in the folding portion FP.

[0083] In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 175 μm and the radius of curvature R is about 1.0 mm, the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP may be in the range of about 100 / 70000 to about 2000 / 70000. In the case where the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 175 μm, the radius of curvature R is about 1.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is less than about 100 / 70000, buckling may occur in the folded portion FP, and thus irreversible changes in physical properties may occur. When the thickness W1 between the first folding surface WFS1 and the second folding surface WFS2 is about 175 μm, the curvature radius R is about 1.0 mm, and the ratio of the Young's modulus of the folded portion FP to the Young's modulus of the non-folded portion NFP is greater than about 2000 / 70000, the tensile strain may exceed about 2.5%, and thus cracks may occur in the folded portion FP.

[0084] Although the embodiments of the present disclosure have been described, it is understood that the present disclosure should not be limited to these embodiments, but a person of ordinary skill in the art may make various changes and modifications within the spirit and scope of the present disclosure as claimed below. Therefore, the subject matter of the present disclosure should not be limited to any single embodiment described herein, and the scope of the inventive concept should be determined according to the claims.

Claims

1. A display device, include: a display module foldable relative to a folding axis extending in a first direction; and A window is provided on the display module and includes a folding portion and a non-folding portion, wherein the folding portion includes: a first folding surface adjacent to the display module, the first folding surface comprising a plurality of first grooves defined therein; and a second folding surface opposite to the first folding surface and spaced apart from the first folding surface by the thickness of the window, the second folding surface comprising a plurality of second grooves defined in the second folding surface, wherein The folding portion is folded relative to the folding axis, and The ratio of the Young's modulus of the folded portion to the Young's modulus of the non-folded portion is in the range of 30 / 70000 to 2000 / 70000.

2. The display device according to claim 1, wherein The thickness of the window is in the range of 100 μm to 175 μm, and The curvature radius of the folded portion after being folded relative to the folding axis is in the range of 1.0 mm to 2.0 mm. The display device according to claim 2 , wherein the thickness of the window is 100 μm.

4. The display device according to claim 2, wherein The thickness of the window is 125 μm, The radius of curvature is in the range of 1.0 mm to 1.5 mm, and The ratio of the Young's modulus of the folded portion to the Young's modulus of the unfolded portion is in the range of 50 / 70000 to 2000 / 70000.

5. The display device according to claim 2, wherein The ratio of the Young's modulus of the folded portion to the Young's modulus of the unfolded portion is in the range of 75 / 70000 to 2000 / 70000; and The thickness of the window is 150 μm and the radius of curvature is 1.0 mm, or the thickness of the window is 125 μm and the radius of curvature is 2.0 mm.

6. The display device according to claim 2, wherein The ratio of the Young's modulus of the folded part to the Young's modulus of the non-folded part is in the range of 100 / 70000 to 2000 / 70000; and the thickness of the window is 175μm and the radius of curvature is 1.0mm, or the thickness of the window is in the range of 150μm to 175μm and the radius of curvature is in the range of 1.5mm to 2.0mm. 7 . The display device according to claim 1 , wherein the Young's modulus of the non-folded portion is in the range of 65 GPa to 75 GPa. 8 . The display device according to claim 1 , wherein the plurality of first grooves and the plurality of second grooves are arranged in an alternating manner in a second direction intersecting the first direction in a plan view.

9. The display device according to claim 1, wherein The window comprises a plurality of first folded middle sections and a plurality of second folded middle sections, The plurality of first folded middle portions overlap the plurality of first grooves respectively in a plan view, The plurality of second folded middle portions overlap the plurality of second grooves respectively in a plan view, and A thickness of each of the plurality of first folded middle portions and a thickness of each of the plurality of second folded middle portions are in a range of 35 μm to 40 μm. 10 . The display device of claim 9 , wherein the thickness of each of the plurality of first folded middle portions and the thickness of each of the plurality of second folded middle portions are equal to each other. 11 . The display device according to claim 1 , wherein a width of each of the plurality of first grooves and each of the plurality of second grooves in a second direction intersecting the first direction is in a range of 80 μm to 100 μm. 12 . The display device according to claim 1 , wherein a width of a side wall portion of the folded portion disposed between one of the plurality of first grooves and one of the plurality of second grooves adjacent to the one of the plurality of first grooves is in a range of 25 μm to 35 μm. 13 . The display device according to claim 1 , wherein each of a distance between two adjacent ones of the plurality of first grooves and a distance between two adjacent ones of the plurality of second grooves is in a range of 120 μm to 150 μm.

14. The display device according to claim 1, further comprising: include: A protective film is disposed on the window.

15. The display device of claim 1, wherein the window comprises a glass material. 16 . The display device of claim 1 , wherein the plurality of first grooves and the plurality of second grooves do not overlap the non-folding portion in a plan view.

17. A window module, include: A window, including a folding portion and a non-folding portion; as well as A protective film is provided on the window, The folding part comprises: a first folding surface including a plurality of first grooves defined therein; and a second folding surface including a plurality of second grooves defined therein, the second folding surface being opposite to the first folding surface and spaced apart from the first folding surface by the thickness of the window, wherein the folding portion is folded relative to a folding axis extending in a first direction, The ratio of the Young's modulus of the folded portion to the Young's modulus of the non-folded portion is in the range of 30 / 70000 to 2000 / 70000, and The shortest distance between the folding axis and the upper surface of the protective film is in the range of 1.0 mm to 2.0 mm.

18. The window module according to claim 17, further comprising: include: An adhesive layer is disposed between the window and the protective film. 19 . The window module of claim 17 , wherein the plurality of first grooves and the plurality of second grooves are arranged in an alternating manner in a second direction intersecting the first direction in a plan view. 20 . The window module of claim 17 , wherein the plurality of first grooves and the plurality of second grooves do not overlap the non-folded portion in a plan view.

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