Display device

Abstract

A display device is disclosed. The display device includes a display module, a plurality of bonding units, and a mesh pattern layer. The display module includes a first non-folded area, a second non-folded area, and a folded area disposed between the first non-folded area and the second non-folded area. The plurality of bonding units is disposed under the display module, overlaps the folded area, and is sequentially arranged in a first direction. The mesh pattern layer is disposed between the display module and the plurality of bonding units, and includes a mesh pattern and a plurality of openings defined by the mesh pattern. Accordingly, the display device according to embodiments of the present inventive concept can have excellent visibility.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to Korean Patent Application No. 10-2019-0178832, filed on December 31, 2019, the contents of which are incorporated herein in its entirety by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a display device, and more particularly, to a foldable display device. BACKGROUND

[0004] Smartphones, digital cameras, laptop computers, navigation devices, and smart televisions are examples of electronic devices. Electronic devices can include display panels to deliver information by displaying images to users.

[0005] In the case of smartphones, the demand for larger displays has led to an increase in the size of electronic devices. However, larger smartphones can be less convenient to hold or carry.

[0006] Flexible or foldable display devices have been developed to reduce the size of electronic devices by folding the electronic devices to a fraction of the unfolded size. However, if the electronic device is repeatedly folded, the folding area can show signs of creasing, wrinkling, or other degradation over time. Therefore, there is a need in the art for systems and methods that reduce the impact of folding on the folding area of a display device. SUMMARY

[0007] The present disclosure relates to a display device.

[0008] Embodiments of the inventive concept provide a display device including a display module, a plurality of bonding units, and a mesh pattern layer. The display module includes a first non-folding area, a second non-folding area, and a folding area disposed between the first non-folding area and the second non-folding area. The plurality of bonding units is disposed under the display module, overlaps the folding area, and is sequentially arranged in a first direction. The mesh pattern layer is disposed between the display module and the plurality of bonding units. The mesh pattern layer includes a mesh pattern and a plurality of openings defined by the mesh pattern.

[0009] In embodiments, the mesh pattern can be defined by a plurality of first yarns extending in the first direction and a plurality of second yarns each extending crosswise to the plurality of first yarns. In embodiments, the mesh pattern can be defined by a plurality of first yarns extending in a direction intersecting the first direction at an angle of about 30 degrees to about 60 degrees and a plurality of second yarns each extending crosswise to the plurality of first yarns.

[0010] In an embodiment, the mesh pattern layer can have a thickness of about 80 micrometers to about 150 micrometers. In an embodiment, at least one of the plurality of junction units can have a predetermined step with an adjacent junction unit of the plurality of junction units. Each of the plurality of openings can have an area of about (average step of the junction unit x 0.95) 2 to about (the average step of the junction unit x 1.3) 2 .

[0011] In an embodiment, each of the plurality of openings can have the same shape and area in a plan view. In an embodiment, the mesh pattern layer can overlap with the folding area and the first and second non-folding areas. In an embodiment, the mesh pattern layer can overlap with the folding area and can not overlap with the first and second non-folding areas.

[0012] In an embodiment, each of the plurality of first and second yarns can have a modulus of about 3 GPa to about 4 GPa. In an embodiment, each of the plurality of first and second yarns can include at least one of polyethylene terephthalate (PET), polyether ether ketone (PEEK), poly aniline (PA), and polypropylene (PP).

[0013] In an embodiment, the display device can further include at least one of a film layer and a buffer layer disposed between the display module and the plurality of junction units. In an embodiment, the display device can further include a film layer disposed between the display module and the plurality of junction units. The mesh pattern layer can be disposed under the film layer.

[0014] In an embodiment, the display device can further include a buffer layer disposed between the display module and the plurality of junction units. The mesh pattern layer can be disposed over the buffer layer. In an embodiment, the display module can include a display element layer, a thin film encapsulation layer encapsulating the display element layer, and an input sensing layer disposed directly on the thin film encapsulation layer. In an embodiment, the plurality of junction units can be spaced apart from each other at regular intervals.

[0015] In an embodiment, the display device can further include a window. The window can be disposed over the display module and can include a first non-folding portion overlapping with the first non-folding area, a second non-folding portion overlapping with the second non-folding area, and a folding portion overlapping with the folding area. The folding portion can be foldable, and display surfaces of the first and second non-folding portions can be exposed to the outside.

[0016] In an embodiment of the disclosure, a display device includes a window, a display module, and a mesh pattern layer. The window can include a folding portion, a first non-folding portion, and a second non-folding portion spaced apart from each other, the folding portion being between the first non-folding portion and the second non-folding portion. The display module can be disposed under the window. The mesh pattern layer can include a mesh pattern and a plurality of openings. The mesh pattern layer can be disposed under the display module. The openings can be defined by the mesh pattern and can have the same shape and the same area. The mesh pattern can be defined by a plurality of first yarns extending in a first direction and a plurality of second yarns each extending to cross the plurality of first yarns.

[0017] In an embodiment, a display device can operate in at least one of a first operation mode and a second operation mode. The first operation mode can be an operation mode in which a display surface of the first non-folding portion and a display surface of the second non-folding portion face each other when the folding portion is folded. The second operation mode can be an operation mode in which the display surface of the first non-folding portion and the display surface of the second non-folding portion are exposed to the outside when the folding portion is folded.

[0018] In an embodiment, the display device can further include a plurality of junction units. The plurality of junction units can overlap the folding portion and can be disposed under the mesh pattern. In an embodiment, the plurality of junction units can include a first junction unit and a second junction unit having a first step from the first junction unit. An area of each of the plurality of openings is about (the first step x 0.95) 2 to about (the first step x 1.3) 2 .

[0019] In an embodiment of the inventive concept, the display device includes a display module and a mesh pattern layer. The display module includes a folding area and a non-folding area adjacent to the folding area. The mesh pattern layer is disposed under the display module and can include a mesh pattern and openings. The openings are defined by the mesh pattern. The mesh pattern can be defined by a plurality of first yarns extending in a first direction and a plurality of second yarns each extending transversely to the plurality of first yarns. An m-th first yarn of the first yarns is disposed over an n-th second yarn of the second yarns and under an (n+1)-th second yarn of the second yarns. Alternatively, the m-th first yarn of the first yarns is disposed under the n-th second yarn of the second yarns and over the (n+1)-th second yarn of the second yarns. An (m+1)-th first yarn of the first yarns is disposed over the n-th second yarn of the second yarns and under the (n+1)-th second yarn of the second yarns. Alternatively, the (m+1)-th first yarn of the first yarns is disposed under the n-th second yarn of the second yarns and over the (n+1)-th second yarn of the second yarns. Here, m and n are each an odd number equal to or greater than 1.

[0020] In an embodiment, in an overlapping portion of the first yarn and the second yarn, a shortest distance between a top of the first yarn and a bottom of the second yarn can be about 80 micrometers to about 150 micrometers. In an embodiment, the display device can further include a plurality of bonding units. The plurality of bonding units can be disposed under the mesh pattern layer and can overlap the folding area.

[0021] Embodiments of the present disclosure include a display device including a display module, a plurality of joints disposed under the display module and configured to support folding of the display device, and a mesh pattern layer disposed between the display module and the joints, wherein the mesh pattern layer includes a mesh pattern and a plurality of openings defined by the mesh pattern, and wherein the openings have an average size between a lower limit value determined based on a visibility parameter and an upper limit value determined based on an adhesion parameter. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the inventive concept, and are incorporated in and constitute a part of this disclosure. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain principles of the inventive concept. In the drawings:

[0023] Figure 1A is a perspective view showing a display device according to an embodiment of the inventive concept in a first operation;

[0024] Figure 1B is a perspective view of a display device according to an embodiment of the inventive concept in a second operation;

[0025] Figure 1C is a perspective view of a display device according to an embodiment of the inventive concept in a third operation;

[0026] Figure 2A is a perspective view of a display device according to an embodiment of the inventive concept in a first operation;

[0027] Figure 2B is a perspective view of a display device according to an embodiment of the inventive concept in a second operation;

[0028] Figure 3A is an exploded perspective view of a display device according to an embodiment of the inventive concept;

[0029] Figure 3B is an exploded perspective view of a display device according to an embodiment of the inventive concept;

[0030] Figure 4 is a magnified view of some of the joining units according to an embodiment of the inventive concept;

[0031] Figure 5A is a plan view of a grid pattern layer according to an embodiment of the inventive concept;

[0032] Figure 5B is a plan view of a grid pattern layer according to an embodiment of the inventive concept;

[0033] Figure 5C is a cross-sectional view of a grid pattern layer according to an embodiment of the inventive concept;

[0034] Figure 6A is a cross-sectional view of a display device according to an embodiment of the inventive concept;

[0035] Figure 6B is a cross-sectional view of a display device according to an embodiment of the inventive concept;

[0036] Figure 6C is a cross-sectional view of a display device according to an embodiment of the inventive concept;

[0037] Figure 7 is a cross-sectional view of a display module according to an embodiment of the inventive concept;

[0038] Figure 8 is a cross-sectional view of a display panel according to an embodiment of the inventive concept;

[0039] Figures 9A-9Dis a view showing display devices with and without a grid pattern layer for visibility comparison;

[0040] Figures 10A-10D is a view showing display devices according to areas of openings for visibility comparison; and

[0041] Figure 11 is a graph showing tensile strain and tensile stress in an extension direction of a grid pattern layer. DETAILED DESCRIPTION

[0042] A flexible display device can be deformed into a curved shape, or can be folded or rolled. A flexible display device capable of being deformed into various shapes is easy to carry and can increase user convenience.

[0043] In a flexible display device, a foldable display device is folded with respect to a folding axis extending in one or more directions. In the entire life of the flexible display device, visibility can be deteriorated at a folding portion after repeatedly performing a folding operation. For example, a wrinkle generated when folding the flexible display device can be visually recognized, or a joint unit provided in the folding portion can be visually recognized.

[0044] A display device of the disclosure includes a grid pattern layer disposed between a display module and a plurality of joint units, wherein the grid pattern layer includes a grid pattern and a plurality of openings defined by the grid pattern. Through the grid pattern layer, a problem in which a wrinkle or a multi-joint hinge appearing in a folding portion is recognized can be reduced.

[0045] In the disclosure, it will be understood that when an element (or region, layer, or part, etc.) is referred to as being "on" another element, "connected to" or "coupled to" another element, it can be directly on, directly connected to, or directly coupled to the other element or layer, or an intervening element or an intervening layer can exist.

[0046] The same reference numerals refer to the same elements throughout the specification. In the drawings, the thickness, proportions, and dimensions of elements are exaggerated for effective description of the technical content.

[0047] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0048] It will be understood that, although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the teachings of the present application. The singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0049] For ease of description, terms such as "below," "under," "lower," "above," "over," and the like can be used herein to describe one element or feature's relationship to another element or feature as shown in the figures. It will be understood that these terms are spatial relative terms and are described with reference to the orientation depicted in the figures.

[0050] Additionally or alternatively, the term "on" in the present disclosure can include instances where an element or feature is disposed at a lower as well as an upper portion.

[0051] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0052] It will be further understood that the terms "comprises" and / or "comprising," when used in this disclosure, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0053] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings.

[0054] Figure 1A is a perspective view showing a display device DD according to an embodiment of the present inventive concept in a first operation mode. Figure 1B is a perspective view showing a display device DD according to an embodiment of the present inventive concept in a second operation mode. Figure 1C is a perspective view showing a display device DD according to an embodiment of the present inventive concept in a third operation mode.

[0055] As Figure 1AAs shown in FIG. 1, in the first operation mode, the display surface IS on which the image IM is displayed is parallel to a surface defined by the first direction DR1 and the second direction DR2. The third direction DR3 represents a normal direction of the display surface IS, i.e., a thickness direction of the display device DD. The front surface (or upper surface) and the rear surface (or bottom surface) of each member are distinguished from each other by the third direction DR3. However, the directions represented by the first direction DR1, the second direction DR2, and the third direction DR3 are relative concepts. Thus, these directions can be converted to other directions. Hereinafter, the first direction to the third direction are the directions indicated by the first direction DR1, the second direction DR2, and the third direction DR3, respectively, and the same reference numerals are referred to. In the present disclosure, the expression "when viewed in a plan view" means that a structure under consideration is viewed in the third direction DR3.

[0056] Figures 1A-1C A foldable display device DD is shown as an example of a flexible display device DD. However, the display device according to an embodiment of the present inventive concept can be a rollable display device DD or a bendable display device DD that is rolled up, and the display device is not particularly limited. In the present disclosure, a flexible display device and a display device are denoted by the same reference numeral "DD", and a foldable display device, a rollable display device, a bendable display device, and a display device are denoted by the same reference numeral "DD". The flexible display device DD according to an embodiment of the present inventive concept can be used in a large electronic device such as a television or a monitor, and can also be used in a medium or small electronic device such as a mobile phone, a tablet, a car navigation device, a game machine, and a smart watch. Hereinafter, the display device DD will be described as a foldable display device DD.

[0057] As Figure 1A As shown in FIG. 1, the display surface IS of the display device DD can include a plurality of regions. The display device DD includes a display region DD-DA on which the image IM is displayed and a non-display region DD-NDA adjacent to the display region DD-DA. The non-display region DD-NDA is a region on which the image IM is not displayed. In Figure 1A In FIG. 1, a clock widget is shown as an example of the image IM. As an example, the display region DD-DA can have a rectangular shape. The non-display region DD-NDA can surround the display region DD-DA. However, the shape of the display region DD-DA and the shape of the non-display region DD-NDA are not limited thereto, and the shape of the display region DD-DA and the shape of the non-display region DD-NDA can be relatively designed. In an embodiment, the non-display region DD-NDA can be omitted.

[0058] As Figures 1A-1CAs shown, the display surface IS of the display device DD may include multiple regions defined according to the operation type. The display device DD may include a folded region FA folded about a folding axis FX and non-folded regions NFA1 and NFA2 that are not folded. The folded region FA may be located between the first non-folded region NFA1 and the second non-folded region NFA2. Although Figures 1A-1C A display device DD is shown, comprising a folded region FA and two non-folded regions NFA1 and NFA2; however, embodiments of the present invention are not limited thereto. For example, the display device DD may include one folded region and one non-folded region. Alternatively, the display device DD may include three or more non-folded regions and two or more folded regions. In this case, at least two folding axes FX may be defined.

[0059] like Figure 1B As shown, the display device DD can be folded forward into itself (inward bending) so that the display surfaces IS of the two non-folded regions NFA1 and NFA2 face each other. Figure 1C As shown, the display device DD can fold itself backward (bend outward), so that the display surface IS is exposed to the outside.

[0060] In an embodiment of the present invention, the display device DD can... Figure 1A and Figure 1B The display device DD can be configured to operate in at least one of the operating modes shown. Figure 1A and Figure 1B The operating mode is shown. However, embodiments of the present invention are not limited to this, and the folding area FA can be defined differently to correspond to the type of user-operated display device DD. For example, different from Figure 1B and Figure 1C The folded region FA can be defined as parallel to the first direction DR1, or the folded region FA can be defined in the diagonal direction.

[0061] When the display device DD includes two non-foldable regions NFA, the areas of the non-foldable regions NFA can be equal, but the embodiments of the present invention are not limited to this. The area of ​​the non-foldable region NFA can be larger than the area of ​​the foldable region FA. In the embodiments, the area of ​​the foldable region FA is not fixed, but can be determined based on the radius of curvature. Figures 1A-1C The example shown illustrates the case where the display device DD is folded about the short axis.

[0062] Figure 2A This is a perspective view of a display device DD-1 according to an embodiment of the present invention during first operation. Figure 2BThis is a perspective view of a display device DD-1 according to an embodiment of the present invention in a second operation.

[0063] Reference Figure 2A and Figure 2B The display device DD-1 may include a first non-foldable region NFA1', a second non-foldable region NFA2', and a foldable region FA' disposed between the first non-foldable region NFA1' and the second non-foldable region NFA2'. The first non-foldable region NFA1', the second non-foldable region NFA2', and the foldable region FA' may be arranged on a second direction DR2.

[0064] The folding region FA' can be bent about a folding axis FX' parallel to the first direction DR1, allowing the display device DD-1 to be folded. The folding axis FX' can be defined as a long axis parallel to the long side of the display device DD-1. Besides folding the display device DD-1 about its long axis, as referenced... Figures 1A-1C The same description can be applied to Figure 2A and Figure 2B The display device DD-1 is shown. For example, the display device DD-1 can be folded by outward bending to expose the display surface IS to the outside. Although not shown, the display device DD-1 can be folded by inward bending so that the display surfaces IS face each other.

[0065] In the following, this disclosure will describe the case in which the display device DD is folded about its short axis. However, it will be understood that the inventive concept described below can also be applied to the display device DD-1 with respect to its long axis folding.

[0066] Figure 3A This is an exploded perspective view of a display device DD according to an embodiment of the present invention. Figure 3B This is an exploded perspective view of a display device DD according to an embodiment of the present invention.

[0067] Reference Figure 3A and Figure 3BA display device DD according to an embodiment of the present invention may include a window WD, a display module DM, a grid pattern layer MS, a plurality of bonding units JU, and a lower cover BC. Although not shown, an adhesive layer may be disposed between the window WD and the display module DM. Additionally or alternatively, an adhesive layer may be disposed between the display module DM and the grid pattern layer MS. Adhesive layers may be disposed between the plurality of bonding units JU and the grid pattern layer MS, and between the lower cover BC and the grid pattern layer MS. The window WD may include a folded portion WD-FA and non-folded portions WD-NFA1 and WD-NFA2 spaced apart from each other, the folded portion WD-FA being between the non-folded portions WD-NFA1 and WD-NFA2. The folded portion WD-FA may overlap with the folded area FA. The non-folded portions WD-NFA1 and WD-NFA2 may overlap with the non-folded areas NFA1 and NFA2. The upper surface of the window WD may be a display surface IS (FIG. 1) for displaying an image. The window WD may comprise glass or plastic. The window WD may be a thin film substrate of approximately 100 micrometers or smaller. Although not shown, the film used to protect the window WD can also be attached to the window WD.

[0068] The display module DM can be positioned below the window WD. As described in the display device DD, the display module DM may include a first non-folding region NFA1, a second non-folding region NFA2, and a folded region FA disposed between the first non-folding region NFA1 and the second non-folding region NFA2. The first non-folding region NFA1, the second non-folding region NFA2, and the folded region FA can be arranged on a first direction DR1.

[0069] Reference Figure 3A The mesh pattern layer MS can be configured to overlap with the folded region FA and the non-folded regions NFA1 and NFA2. However, the embodiments are not limited to this, and as... Figure 3B As shown, the mesh pattern layer MS can be configured to overlap with the folded region FA, but not with the non-folded regions NFA1 and NFA2. In an embodiment, when multiple folded regions FA are provided, the mesh pattern layer MS can be provided to overlap with the multiple folded regions FA.

[0070] When the grid pattern layer MS does not overlap with the non-folded regions NFA1 and NFA2, the adhesive layer ADH can be disposed in the non-folded regions NFA1 and NFA2 instead of the grid pattern layer MS. For example, the adhesive layer ADH can be disposed between the first lower cover BC1 and the second lower cover BC2 and the display module DM. The adhesive layer ADH can be an optically transparent adhesive layer. The optically transparent adhesive layer can be an optically transparent adhesive resin or an optically transparent adhesive tape. The adhesive layer can be a pressure-sensitive adhesive (PSA). The adhesive layer can contain, for example, an acrylic adhesive material.

[0071] The joining unit JU can be disposed below the grid pattern layer MS. The joining unit JU can overlap with the folded area FA. Specifically, the joining unit JU can overlap with the folded portion WD-FA. The joining unit JU can extend in the second direction DR2 and can be arranged in the first direction DR1. The joining units JU can be spaced apart from each other at regular intervals in the first direction DR1. The joining unit JU can be disposed between the first lower cover BC1 and the second lower cover BC2. The joining unit JU can be coupled to the grid pattern layer MS via an adhesive layer to protrude downwards.

[0072] For the first direction DR1, the width of each joining unit JU can become smaller from the top to the bottom of each joining unit JU. For example, when viewed in the second direction DR2, each joining unit JU can have a trapezoidal shape in which the length of the upper side is wider than the length of the lower side. However, this is only illustrative, and the joining unit JU can have various shapes.

[0073] For the third-party DR3, the joining unit JU can have the same thickness as each of the first lower cover BC1 and the second lower cover BC2. However, this is only illustrative, and the thickness of each joining unit JU can be different from the thickness of each of the first lower cover BC1 and the second lower cover BC2.

[0074] The lower cover BC can be located at the bottom of the display device DD to accommodate the components of the display device DD. The lower cover BC can include a first lower cover BC1 and a second lower cover BC2. The first lower cover BC1 is located below the grid pattern layer MS and overlaps with the first non-folded area NFA1, and the second lower cover BC2 is located below the grid pattern layer MS and overlaps with the second non-folded area NFA2.

[0075] Although not shown, the display device DD may also include a hinge portion connected to the first lower cover BC1 and the second lower cover BC2. The hinge portion may be used to provide a folding shaft FX extending in the second direction DR2. The hinge portion may accommodate an engagement unit JU.

[0076] Figure 4 This is an enlarged view illustrating some of the joining units JU according to an embodiment of the present invention.

[0077] Reference Figure 4In an embodiment, the bonding unit JU may include a first bonding unit JU1 and a second bonding unit JU2. The upper component to which the bonding unit JU is attached may have minor bends that may occur during the process. Additionally or alternatively, when the bonding units JU are attached, the thickness of the adhesive layer between each bonding unit JU and the upper component may vary. Therefore, when each of the plurality of bonding units JU is attached to the upper component, steps may appear between the bonding units JU.

[0078] Each joining unit JU can have a predetermined step with its adjacent joining unit. For example, the first joining unit JU1 and the second joining unit JU2 can have a first step G1. Figure 4 As shown, the first step G1 is defined as the shortest distance between a plane parallel to the upper surface of the first joining unit JU1 and a plane parallel to the upper surface of the second joining unit JU2 (assuming that the plane parallel to the upper surface of the first joining unit JU1 and the plane parallel to the upper surface of the second joining unit JU2 are parallel to each other). The average value of the steps of the multiple joining units JU can be from about 30 micrometers to about 200 micrometers.

[0079] If the multiple bonding units JU have predetermined steps relative to each other, one or more of the multiple bonding units JU can be visually identified on the display surface IS (FIG. 1) of the display device DD. Additionally or alternatively, even when the bonding units JU are omitted, spots or other visual indications may still be visually identifiable due to bending or other issues between the components of the display device. Because the display device DD of the embodiment includes a grid pattern layer MS, the above-mentioned problems can be mitigated or prevented.

[0080] Figure 5A This is a plan view of a grid pattern layer MS according to an embodiment of the present invention. Figure 5B This is a plan view of a grid pattern layer MS according to an embodiment of the present invention. Figure 5C This is a cross-sectional view of a mesh pattern layer MS according to an embodiment of the present invention.

[0081] Reference Figure 5A The mesh pattern layer MS may include a mesh pattern MP and multiple openings OP. The mesh pattern MP and the openings OP may be defined by multiple first yarns TH1 and multiple second yarns TH2. The openings OP may have the same shape and the same area.

[0082] Reference Figure 5AThe first yarn TH1 may extend in a first direction DR1. The first yarns TH1 may be spaced apart from each other at regular intervals in a second direction DR2. The second yarn TH2 may extend to intersect each of the first yarns TH1. The second yarns TH2 may be spaced apart from each other at regular intervals. For example, the second yarn TH2 may intersect the first yarn TH1 in a second direction DR2 perpendicular to the first direction DR1. In this case, when viewed in a third direction DR3, the opening OP may be defined in the form of a square or rectangle.

[0083] However, this is merely illustrative, and the embodiments are not limited thereto. The first yarn TH1 and the second yarn TH2 may intersect each other in various directions. If some or all of the openings OP have the same shape and the same area, the openings OP may be defined in other shapes than rectangles.

[0084] The m-th first yarn TH1 in the first yarn TH1 can be positioned above the n-th second yarn TH2 in the second yarn TH2, and below the (n+1)-th second yarn TH2 in the second yarn TH2. Alternatively, the m-th first yarn TH1 in the first yarn TH1 can be positioned below the n-th second yarn TH2 in the second yarn TH2, and above the (n+1)-th second yarn TH2 in the second yarn TH2. Here, m and n are each odd numbers equal to or greater than 1.

[0085] The (m+1)th first yarn TH1 in the first yarn TH1 can be positioned above the nth second yarn TH2 in the second yarn TH2 and below the (n+1)th second yarn TH2 in the second yarn TH2. Alternatively, the (m+1)th first yarn TH1 in the first yarn TH1 can be positioned below the nth second yarn TH2 in the second yarn TH2 and above the (n+1)th second yarn TH2 in the second yarn TH2.

[0086] For example, each first yarn TH1 can be arranged to alternately cross with the second yarn TH2.

[0087] In this embodiment, because the display device DD includes a grid pattern layer MS, it is possible to prevent the visual identification of spots or joint units JU in the folded area FA. When the display device DD includes an opening OP, it is determined that the opening OP reduces the bending between the components of the display device DD and the steps between the joint units JU.

[0088] When the shape of the opening OP is square, the length of one side of the opening OP can be equal to or greater than approximately 0.95 times the average step size of the joining unit JU and less than or equal to approximately 1.3 times the average step size of the joining unit JU. For example, the area of ​​each opening OP can be approximately [average step size of the joining unit JU × 0.95]. 2 Approximately [average step size of joint unit JU × 1.3] 2 .

[0089] For the entire area of ​​the mesh pattern layer MS, a higher proportion of openings (OPs) effectively reduces steps. Therefore, as the proportion of openings (OPs) increases, the visibility of the display device DD can be improved. However, when the proportion of openings (OPs) is too high, the bonding area of ​​the mesh pattern layer MS becomes smaller. Therefore, the adhesion of the mesh pattern layer MS may deteriorate. When the area of ​​each opening (OP) meets the above-mentioned range, the bonding area of ​​the mesh pattern layer MS can be sufficiently ensured while improving the visibility of the display device DD.

[0090] Therefore, embodiments of this disclosure include a display device (e.g., display device DD), the display device comprising: a display module (e.g., display module DM); a plurality of connectors (e.g., connector units JU) disposed below the display module and configured to support folding of the display device; and a grid pattern layer (e.g., Figure 5A Mesh pattern layer MS or Figure 5B A grid pattern layer MS-1 is disposed between the display module and the connector, wherein the grid pattern layer includes a grid pattern (e.g., Figure 5A Grid pattern MP or Figure 5B The grid pattern MP-1 and a plurality of openings (e.g., openings OP) defined by the grid pattern, wherein the openings have an average size between a lower limit determined based on a visibility parameter (i.e., the ratio of the opening size to the joint unit step sufficient to achieve improved visibility) and an upper limit determined based on an adhesion parameter (i.e., the ratio of the opening size to the joint unit step small enough to achieve sufficient adhesion of the grid pattern layer).

[0091] Because the mesh pattern layer MS comprises a first yarn TH1 and a second yarn TH2, the process efficiency for forming the mesh pattern layer MS can be improved. The area of ​​the opening OP can be adjusted by adjusting the spacing between the first yarn TH1 and the second yarn TH2. The thickness of the mesh pattern layer MS can be adjusted by adjusting the thickness of the first yarn TH1 and the second yarn TH2.

[0092] However, in embodiments, the mesh pattern MP may not be defined by the first yarn TH1 and the second yarn TH2. For example, the mesh pattern MP may be formed as a single integral shape.

[0093] ReferenceFigure 5B The first yarn TH1 can extend along a fourth direction DR4, intersecting the first direction DR1 at an angle of approximately 30 to approximately 60 degrees. The fourth direction DR4 can be a direction between the first direction DR1 and the second direction DR2. For example, the fourth direction DR4 can be a direction intersecting the first direction DR1 at an angle of approximately 45 degrees. For example, the second yarn TH2 can intersect the first yarn TH1 along a fifth direction DR5, perpendicular to the fourth direction DR4. In this case, when viewed along the third direction DR3, the grid pattern MP-1 can have a diamond shape.

[0094] In such Figure 5B In the case where the grid pattern layer MS-1 is formed as shown, when the grid pattern layer MS-1 is stretched in the first direction DR1 or the second direction DR2, the grid pattern layer MS-1 has a higher density than... Figure 5A The mesh pattern layer shown has high tensile strain.

[0095] Depending on the radius of curvature of the foldable display device DD, the characteristics of the mesh pattern layers MS and MS-1 may change. For example, for a display device DD folded by inward bending, the tensile strain of the mesh pattern layers MS and MS-1 may be high as the radius of curvature decreases. Therefore, Figure 5B The grid pattern layer MS-1 shown can be applied to a display device DD that is folded inwards.

[0096] Figure 5C This is a cross-sectional view of a mesh pattern layer MS according to an embodiment of the present invention. Figure 5C In the middle, it is shown that along Figure 5A The cross section intercepted by line I-I'.

[0097] Reference Figure 5C The first yarn TH1 and the second yarn TH2 may each have predetermined thicknesses T1 and T2. The mesh pattern layer MS may also have a predetermined thickness T3. The thickness T1 of the first yarn TH1 and the thickness T2 of the second yarn TH2 may be the same as or different from each other, but may be the same. The thickness T3 of the mesh pattern layer MS may be from about 80 micrometers to about 150 micrometers. In the overlapping portion of the first yarn TH1 and the second yarn TH2, the shortest distance between the top of the first yarn TH1 and the bottom of the second yarn TH2 is between about 80 micrometers and about 150 micrometers.

[0098] When the thickness T3 of the mesh pattern layer MS is 80 micrometers or less, the effect of improving visibility may be insufficient because the opening OP does not have enough thickness. When the thickness T3 of the mesh pattern layer MS exceeds 150 micrometers, the durability of the display device DD may deteriorate because the mesh pattern layer MS undergoes plastic deformation during the folding process.

[0099] Depending on the degree of stretching, the thickness T3 of the mesh pattern layer MS can be less than or greater than the sum of the thickness T1 of the first yarn TH1 and the thickness T2 of the second yarn TH2. When the mesh pattern layer MS is stretched strongly, the first yarn TH1 and the second yarn TH2 may be compressed against each other. Therefore, the thickness T3 of the mesh pattern layer MS can be less than the sum of the thickness T1 of the first yarn TH1 and the thickness T2 of the second yarn TH2. When the mesh pattern layer MS is stretched slightly, space may be created between the first yarn TH1 and the second yarn TH2. Therefore, the thickness T3 of the mesh pattern layer MS can be greater than the sum of the thickness T1 of the first yarn TH1 and the thickness T2 of the second yarn TH2.

[0100] The first yarn TH1 and the second yarn TH2 can have Young's modulus values ​​of approximately 3 GPa to approximately 4 GPa. In the example scenario, when the modulus values ​​of the first yarn TH1 and the second yarn TH2 are less than 3 GPa, the steps of the bending or joining unit JU between the components of the display device DD may not be sufficiently relaxed. When the modulus values ​​of the first yarn TH1 and the second yarn TH2 exceed 4 GPa, plastic deformation may occur in the first yarn TH1 and the second yarn TH2 during folding.

[0101] Each of the first yarn TH1 and the second yarn TH2 may include at least one of polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyaniline (PA), and polypropylene (PP). When each of the first yarn TH1 and the second yarn TH2 includes polyethylene terephthalate (PET), polyaniline (PA), or polypropylene (PP), a crosslinking agent may be included to improve rigidity.

[0102] Figure 6A This is a cross-sectional view of the display device DD-2 according to an embodiment of the present invention. Figure 6B This is a cross-sectional view of the display device DD-3 according to an embodiment of the present invention. Figure 6C This is a cross-sectional view of the display device DD-4 according to an embodiment of the present invention.

[0103] Reference Figures 6A-6C The display devices DD-2, DD-3 and DD-4 according to the embodiments further include at least one of the buffer layer CS and the protective film PF.

[0104] Reference Figure 6A In the display device DD-2 of this embodiment, the buffer layer CS and the protective film PF can absorb external impact vibrations. The protective film PF is also referred to as a film layer. (See reference...) Figure 6A At least one of the protective film PF and the buffer layer CS can be disposed between the display module DM and the multiple bonding units JU. Specifically, refer to Figure 6AThe buffer layer CS is shown as being disposed below the grid pattern layer MS, but the embodiment is not limited thereto. The buffer layer CS may be disposed above the grid pattern layer MS.

[0105] The cushioning layer CS can include a cushioning material for absorbing external impacts. For example, the cushioning layer CS can be provided by foaming. The cushioning layer CS can include various compounds such as silicone resin.

[0106] The protective film PF prevents external moisture from penetrating the display module DM and absorbs external impacts. Figure 6A In this embodiment, the protective film PF is shown disposed above the grid pattern layer MS, but the embodiment is not limited thereto. For example, the protective film PF may be disposed below the grid pattern layer MS, or between the grid pattern layer MS and the buffer layer CS. The protective film PF may include a plastic film as a base layer. The protective film PF may include a plastic film comprising any one selected from the group consisting of polyethersulfone (PES), polyacrylate, polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polyimide (PI), polycarbonate (PC), polyarylene ether sulfone, and combinations thereof.

[0107] Reference Figure 6A A first adhesive layer ADH1 can be disposed between the joining unit JU and the buffer layer CS. Although the first adhesive layer ADH1 is shown as being integrally disposed on the folded region FA, it can actually be disposed on the contact surface between the joining unit JU and the buffer layer CS. A second adhesive layer ADH2 can be disposed between the buffer layer CS and the grid pattern layer MS, such that the buffer layer CS and the grid pattern layer MS are attached to each other. A third adhesive layer ADH3 can be disposed between the grid pattern layer MS and the protective film PF, such that the grid pattern layer MS is attached to the protective film PF. The second adhesive layer ADH2 and the third adhesive layer ADH3 can be provided in the form of adhesive tape.

[0108] When the second adhesive layer ADH2 and the third adhesive layer ADH3 are provided in the form of adhesive resin, the openings OP of the grid pattern layer MS can be filled with resin. In this case, the visibility of the display device DD can be reduced. The fourth adhesive layer ADH4 can be disposed between the protective film PF and the display module DM, so that the protective film PF is attached to the display module DM. The same material as the adhesive layer ADH can be used for the first adhesive layer ADH1, the second adhesive layer ADH2, the third adhesive layer ADH3, and the fourth adhesive layer ADH4.

[0109] The materials constituting the protective film PF are not limited to plastic resins and may include organic or inorganic composite materials. The protective film PF may include a porous organic layer and inorganic materials filling the pores of the porous organic layer. The protective film PF may also include a functional layer provided on the plastic film. The functional layer may include a resin layer. The functional layer may be provided by a coating method.

[0110] Reference Figure 6B The display device DD-3 in this embodiment may further include a buffer layer CS. (Refer to reference...) Figure 6A Compared to the aforementioned display device DD-3, in Figure 6B The protective film PF can be omitted in the display device DD-2 shown. In this case, the grid pattern layer MS can serve the function of the protective film PF. Although the grid pattern layer MS is shown as being disposed above the buffer layer CS, the grid pattern layer MS can be disposed below the buffer layer CS.

[0111] Reference Figure 6C The display device DD-4 in this embodiment may further include a protective film PF. (Refer to reference...) Figure 6A Compared to the aforementioned display device DD-3, in Figure 6C The buffer layer CS can be omitted in the display device DD-4 shown. Because the grid pattern layer MS includes multiple openings OP, it can effectively absorb external impacts. Therefore, the grid pattern layer MS can function as a buffer layer CS to absorb external impacts. Although the grid pattern layer MS is shown as being disposed below the protective film PF, in embodiments, the grid pattern layer MS can be disposed above the protective film PF.

[0112] Figure 7 This is a cross-sectional view of a display module DM according to an embodiment of the present invention. Figure 8 This is a cross-sectional view of a display panel DP according to an embodiment of the present invention.

[0113] Reference Figure 7 and Figure 8 The display module DM may include a display panel DP and an input sensing layer ISL. The display panel DP may include a substrate SUB, a circuit element layer DP-CL, a display element layer DP-DEL, and a thin film encapsulation layer TFE stacked sequentially.

[0114] The display panel DP includes the display area DP-DA and the non-display area DP-NDA. The display area DP-DA of the display panel DP corresponds to... Figures 1A-1C The display area DD-DA is shown, and the non-display area DP-NDA corresponds to... Figures 1A-1C The non-display area DD-NDA is shown in the image.

[0115] The substrate SUB may include at least one plastic film and is a flexible substrate, and may include a plastic substrate, a glass substrate, a metal substrate, or an organic or inorganic composite substrate. Additionally or alternatively, the substrate SUB may include a synthetic resin layer. The synthetic resin layer may include a thermosetting resin. The substrate SUB may have a multilayer structure. For example, the substrate SUB may have a three-layer structure consisting of a synthetic resin layer, an adhesive layer, and a synthetic resin layer. Specifically, the synthetic resin layer may be a polyimide resin layer, and the material of the synthetic resin layer is not specifically limited. The synthetic resin layer may include at least one of acrylic resin, methacrylic resin, polyisoprene, vinyl resin, epoxy resin, polyurethane resin, cellulose resin, siloxane resin, polyamide resin, and perylene resin. Additionally or alternatively, the substrate SUB may include a glass substrate, a metal substrate, or an organic or inorganic composite substrate.

[0116] The circuit element layer DP-CL may include at least one intermediate insulating layer and circuit elements. The intermediate insulating layer includes at least one intermediate inorganic film and at least one intermediate organic film. The circuit elements may include signal lines and pixel driving circuits, etc.

[0117] The display element layer DP-DEL can include an organic light-emitting diode (OLED). The OLED can include a first electrode EL1, a hole transport layer HCL, an emitter layer EML, an electron transport layer ECL, and a second electrode EL2, stacked sequentially. The first electrode EL1 can be an anode. Alternatively or additionally, the first electrode EL1 can be a pixel electrode. The emitter layer EML can include organic emitting materials, but embodiments are not limited thereto. The emitter layer EML can include inorganic emitting materials such as quantum dots or quantum rods. The second electrode EL2 can be a common electrode or a cathode.

[0118] The organic light-emitting diode (OLED) may also include a capping layer disposed on the second electrode EL2. The capping layer may be a layer used to protect the OLED or to modulate its optical properties.

[0119] The display element layer DP-DEL may also include an organic film such as a pixel defining film PDL. The pixel defining film PDL may be disposed on the circuit element layer DP-CL to expose at least a portion of the first electrode EL1. The pixel defining film PDL may define a light-emitting region PXA and a non-light-emitting region NPXA adjacent to the light-emitting region PXA.

[0120] A thin-film encapsulation layer (TFE) encapsulates the display element layer DP-DEL. The TFE can be directly disposed on the organic light-emitting diode (OLED). For example, the TFE can be directly disposed on the second electrode EL2. Alternatively, when the OLED also includes a capping layer (not shown), the TFE can be directly disposed on the capping layer. The TFE may include at least one organic layer and at least one inorganic layer. For example, the insulating layer may include a stacked structure of inorganic, organic, and inorganic layers. The TFE protects the DP-DEL from foreign matter such as moisture, oxygen, and dust particles.

[0121] The input sensing layer (ISL) can be disposed above the display panel (DP). Although not shown, the input sensing layer (ISL) may include an insulating layer and a conductive layer. A substrate insulating layer may be disposed below the input sensing layer (ISL). The substrate insulating layer may be an inorganic insulating layer.

[0122] The input sensing layer (ISL) and the display panel (DP) can be manufactured using a continuous process. The ISL can be directly applied to the display panel (DP). Specifically, as... Figure 7 As shown, the input sensing layer ISL can be directly disposed on the thin-film encapsulation layer TFE. In this disclosure, the statement "structure A is directly disposed on structure B" means that the adhesive layer is not disposed between structure A and structure B, and structure A and structure B are in contact with each other.

[0123] According to an embodiment, the input sensing layer (ISL) can sense external input by sensing the capacitance changed by an external object. For example, the input sensing layer (ISL) can be a capacitive input sensing layer (ISL).

[0124] According to another embodiment of the present invention, the input sensing layer ISL can sense external input by sensing changes in pressure caused by an external object. For example, the input sensing layer ISL can be a pressure-reducing type input sensing layer ISL.

[0125] Figures 9A-9D This is a view showing a display device DD with a grid pattern layer MS and without a grid pattern layer MS for visibility comparison. Figures 10A-10D This is a view of the display device DD showing the area of ​​the opening OP for visibility comparison. Figure 11 It is a graph showing the changes in tensile strain and tensile stress in the extension direction of the mesh pattern layer MS.

[0126] In the following description, reference will be used. Figures 9A-9D , Figures 10A-10D and Figure 11Examples and comparative examples illustrating the inventive concept are provided to describe a display device DD according to embodiments of the inventive concept. Additionally or alternatively, the examples shown below are merely illustrative for understanding the inventive concept, and the scope of the inventive concept is not limited to these examples.

[0127] Manufacturing of the display device according to Example 1 and Comparative Example 1

[0128] A grid pattern layer is prepared using a first yarn and a second yarn containing PEEK. The prepared grid pattern layer is placed between a buffer layer and a bonding unit to manufacture the display device of Example 1. The display device of Example 1 is manufactured in a stacked structure having a bonding unit, a buffer layer, a grid pattern layer, and a display module. The individual components are attached to each other using adhesive members. According to Example 1, the display device is a foldable display device with a radius of curvature of 4 mm.

[0129] Except for omitting the grid pattern layer, the display device of Comparative Example 1 is manufactured to have the same construction as the display device of Example 1.

[0130] Evaluation of the visibility of the display devices based on Example 1 and Comparative Example 1

[0131] For the display device according to Example 1 and Comparative Example 1, the folding operation and unfolding operation (first operation and second operation) are repeated about 150,000 times in an environment with a temperature of about 60°C and a relative humidity of about 93%, so that the display surface of the display device is exposed to the outside.

[0132] Figure 9A The visible state before the display device according to Example 1 is shown, and Figure 9B The visible state is shown after the display device according to Example 1 is folded. Figure 9C The visual state before the display device according to Comparative Example 1 is folded is shown, and Figure 9D The visible state is shown after the display device according to Comparative Example 1 is folded.

[0133] Reference Figure 9A and Figure 9C In the display device of Example 1, the joining unit is not visually identifiable before folding, but in the display device of Comparative Example 1, the joining unit is visually identifiable before folding. (Refer to...) Figure 9B and Figure 9D In the display device of Example 1, the joining unit is not visually identifiable after folding, but in the display device of Comparative Example 1, the joining unit is visually identifiable after folding. (Refer to...) Figures 9A-9DCompared to the display device of Comparative Example 1 which does not include a grid pattern layer, the visibility of the bonding unit of the display device of Example 1 which includes a grid pattern layer can be improved.

[0134] Evaluation of the visibility of a display device based on the area of ​​the openings in the grid pattern.

[0135] Display devices according to Example 2 and Comparative Examples 2 to 4, comprising mesh pattern layers with different opening widths, are manufactured. In the display devices, according to Example 2 and Comparative Examples 2 to 4, the average step of the bonding unit is measured to be approximately ±500 micrometers. The opening width, opening ratio, and thickness of the mesh pattern layer of the display devices according to Example 2 and Comparative Examples 2 to 4 are described in Table 1 below.

[0136]

[0137]

[0138] Table 1

[0139] Figure 10A The image shows the visible state before the display device of Example 2 is folded. Figure 10B The image shows the visible state before the display device of Comparison Example 2 is folded down. Figure 10C The visible state before the display device of Comparison Example 3 is folded is shown, and Figure 10D The view of the display device before folding in comparison example 4 is shown. (Refer to...) Figure 10A The width of the opening therein has (the average step of the joint unit) 2 In Example 2, where the value is [value], no shape of the grid pattern was observed. (See reference [reference]). Figures 10B-10D The width of the opening in it does not meet the requirement of approximately (average step of the joint unit × 0.95). 2 Approximately (average step size of the joint unit × 1.3) 2 In the cases of comparing the values ​​of Example 2 to Example 4, the shape of the grid pattern is observed.

[0140] In Example 2, the width of the opening satisfies approximately (average step of the joint unit × 0.95). 2 Approximately (average step size of the joint unit × 1.3) 2 The value of this value ensures that the opening area is at a proportion sufficient to improve visibility and adequately guarantee the adhesive area. According to Comparative Examples 2 and 3, if the opening area proportion is too small, visibility may not be improved. According to Comparative Example 4, if the opening area proportion is too high, it may be insufficient to guarantee the adhesive area of ​​the mesh pattern layer. Therefore, the adhesive strength of the mesh pattern layer is reduced, and the mesh pattern becomes visually identifiable.

[0141] As a result, the width of the opening satisfies approximately (average step of the joint unit × 0.95). 2 Approximately (average step size of the joint unit × 1.3) 2 The display device of Example 2 with the above value has superior visibility compared to the display devices of Comparative Examples 2 to 4, which do not satisfy the above value.

[0142] Tensile strain and tensile stress in the extension direction of the mesh pattern layer

[0143] Reference Figure 11 The graph shows the tensile strain and tensile stress in the extending direction of the mesh pattern layer. (See reference...) Figure 5A The manufacturing Figure 11 The grid pattern layer gives the opening a rectangular shape. The yarns that make up the grid pattern layer contain PEEK.

[0144] exist Figure 11 In the diagram, when the extension direction is horizontal or vertical (first or second direction), tensile strain and tensile stress are represented by solid lines. When the extension direction is inclined at approximately 45 degrees relative to the horizontal direction (fourth or fifth direction), tensile strain and tensile stress are represented by single-dotted lines. Double-dotted lines represent the tensile strain and tensile stress of the yarns constituting the grid pattern layer.

[0145] Reference Figure 11 When the tensile strain exceeds approximately 6%, the yarns constituting the mesh pattern layer begin to plastically deform. When the mesh pattern layer extends in the vertical or horizontal direction, it begins to plastically deform when the tensile strain is approximately 30% to approximately 40%. When the mesh pattern layer extends in a direction inclined at approximately 45 degrees relative to the horizontal direction, it does not begin to plastically deform even when the tensile strain is approximately 40% or greater.

[0146] In some cases, the elastic range of the mesh pattern layer MS-1 can be wider than that of the mesh pattern layer MS. Therefore, the second yarn TH2 extends in a fourth direction DR4 intersecting the first direction DR1 at an angle of approximately 45 degrees, and the first yarn TH1 extends in a fifth direction DR5 perpendicular to the fourth direction DR4 to intersect each second yarn TH2. Alternatively or additionally, the first yarn TH1 extends in the first direction DR1, and the second yarn TH2 extends in a second direction DR2 perpendicular to the first direction DR1 to intersect each first yarn TH1. Therefore, even when the radius of curvature is small, damage due to deformation can be reduced.

[0147] A display device according to an embodiment of the present invention includes a grid pattern layer disposed between a display module and a plurality of bonding units. The grid pattern layer includes a grid pattern and a plurality of openings defined by the grid pattern. Therefore, according to an embodiment of the present invention, the display device can have improved visibility.

[0148] Additionally or alternatively, the exemplary embodiments disclosed herein are not intended to limit the technical ideas of the invention, and all technical ideas within the scope of the appended claims and their equivalents should be interpreted as being included within the scope of the invention.

[0149] Although exemplary embodiments of the invention have been described, it will be understood that the invention should not be limited to these exemplary embodiments, but rather that various changes and modifications can be made by those skilled in the art within the spirit and scope of the invention.

Claims

1. A display device, wherein, The display device includes: a display module including a first non-folded area, a second non-folded area, and a folded area disposed between the first non-folded area and the second non-folded area; a plurality of bonding units disposed under the display module, overlapping the folded area, and sequentially arranged in a first direction; and a mesh pattern layer disposed between the display module and the plurality of bonding units, overlapping the folded area, and including a mesh pattern and a plurality of openings defined by the mesh pattern, wherein the plurality of openings have an average size between a lower limit value determined based on a visibility parameter and an upper limit value determined based on an adhesion parameter, and wherein the visibility parameter and the adhesion parameter respectively correspond to a ratio of an opening size to a bonding unit step sufficient to achieve improved visibility of the display device and a ratio of an opening size to the bonding unit step sufficient to achieve sufficient adhesion of the mesh pattern layer.

2. The display device according to claim 1, wherein The mesh pattern is defined by a plurality of first yarns extending in the first direction and a plurality of second yarns each extending crosswise to the plurality of first yarns.

3. The display device according to claim 1, wherein The mesh pattern is defined by a plurality of first yarns extending in a direction intersecting the first direction at an angle between 30 degrees and 60 degrees and a plurality of second yarns each extending crosswise to the plurality of first yarns.

4. The display device according to claim 1, wherein A thickness of the mesh pattern layer is between 80 micrometers and 150 micrometers.

5. The display device of claim 1, wherein, at least one bonding unit of the plurality of bonding units has a predetermined step with an adjacent bonding unit of the plurality of bonding units, and An area of each of the plurality of openings is between (an average step of the bonding unit x 0.95) 2 and (the average step of the bonding unit x 1.3) 2 .

6. The display device according to claim 1, wherein each opening of the plurality of openings has a same shape and area in a plan view.

7. The display device according to claim 1, wherein The mesh pattern layer overlaps the folded area and the first and second non-folded areas.

8. The display device according to claim 1, wherein The mesh pattern layer overlaps the folded area and does not overlap the first and second non-folded areas.

9. The display device according to claim 2 or 3, wherein Each yarn of the plurality of first yarns and the plurality of second yarns has a modulus between 3 GPa and 4 GPa.

10. The display device according to claim 2 or 3, wherein Each yarn of the plurality of first yarns and the plurality of second yarns includes at least one of polyethylene terephthalate, polyether ether ketone, polyaniline, and polypropylene.

11. The display device according to claim 1, wherein The display device further includes: at least one of a film layer and a buffer layer disposed between the display module and the plurality of bonding units.

12. The display device according to claim 1, wherein The display device further includes: a film layer disposed between the display module and the plurality of bonding units, wherein, the mesh pattern layer is disposed under the film layer.

13. The display device of claim 1, wherein, The display device further includes: a buffer layer disposed between the display module and the plurality of bonding units, wherein, the mesh pattern layer is disposed over the buffer layer.

14. The display device of claim 1, wherein, the display module includes: a display element layer; a thin film encapsulation layer encapsulating the display element layer; and an input sensing layer disposed directly on the thin film encapsulation layer.

15. The display device of claim 1, wherein, The plurality of joint units are spaced apart from each other at regular intervals.

16. The display device of claim 1, wherein, The display device further includes: a window disposed above the display module and including a first non-folded portion overlapping the first non-folded area, a second non-folded portion overlapping the second non-folded area, and a folded portion overlapping the folded area, wherein when the folded portion is folded, display surfaces of the first non-folded portion and the second non-folded portion are exposed to the outside.

17. A display device, wherein, The display device includes: a window including a folded portion, a first non-folded portion, and a second non-folded portion spaced apart from each other, the folded portion being located between the first non-folded portion and the second non-folded portion; a display module disposed below the window; a mesh pattern layer disposed below the display module, overlapping the folded portion, and including a mesh pattern and a plurality of openings defined by the mesh pattern, wherein the plurality of openings have the same shape and the same area; and a plurality of joint units overlapping the folded portion and disposed below the mesh pattern, wherein the mesh pattern is defined by a plurality of first yarns extending in a first direction and a plurality of second yarns each extending transversely to the plurality of first yarns, and wherein the plurality of openings have an average size between a lower limit value determined based on a visibility parameter and an upper limit value determined based on an adhesion parameter, wherein the visibility parameter and the adhesion parameter respectively correspond to a ratio of an opening size to a joint unit step sufficient to achieve improved visibility of the display device and a ratio of an opening size to the joint unit step sufficient to achieve sufficient adhesion of the mesh pattern layer.

18. The display device of claim 17, wherein the display device is operable in at least one of: a first operation mode in which display surfaces of the first non-folded portion and the second non-folded portion face each other when the folded portion is folded; and a second operation mode in which the display surfaces of the first non-folded portion and the second non-folded portion are exposed to the outside when the folded portion is folded.

19. The display device of claim 17, wherein the plurality of joint units include a first joint unit and a second joint unit having a first step from the first joint unit, and an area of each of the plurality of openings is between (the first step x 0.95) 2 and (the first step x 1.3) 2 .

20. A display device comprising: the display device includes: a display module including a folded area and a non-folded area adjacent to the folded area; and a mesh pattern layer disposed below the display module, overlapping the folded area, and including a mesh pattern and a plurality of openings defined by the mesh pattern; and a plurality of joint units disposed below the mesh pattern layer and overlapping the folded area, wherein, the mesh pattern is defined by a plurality of first yarns extending in a first direction and a plurality of second yarns each extending transversely to the plurality of first yarns, and the plurality of openings have an average size between a lower limit value determined based on a visibility parameter and an upper limit value determined based on an adhesion parameter, wherein the visibility parameter and the adhesion parameter respectively correspond to a ratio of an opening size to a joint unit step sufficient to achieve improved visibility of the display device and a ratio of an opening size to the joint unit step sufficient to achieve sufficient adhesion of the mesh pattern layer. The mesh pattern is defined by a plurality of first yarns extending in a first direction and a plurality of second yarns each extending crosswise to the plurality of first yarns, and wherein an mth first yarn of the first yarns is disposed above an nth second yarn of the second yarns and below an (n+1)th second yarn of the second yarns, or below the nth second yarn of the second yarns and above the (n+1)th second yarn of the second yarns, and an (m+1)th first yarn of the first yarns is disposed above the nth second yarn of the second yarns and below the (n+1)th second yarn of the second yarns, or below the nth second yarn of the second yarns and above the (n+1)th second yarn of the second yarns, wherein m and n are odd numbers equal to or greater than 1, and wherein the plurality of openings have an average size between a lower limit value determined based on a visibility parameter and an upper limit value determined based on a bonding parameter, wherein the visibility parameter and the bonding parameter respectively correspond to a ratio of an opening size to a joining cell step sufficient to achieve improved visibility of the display device and a ratio of an opening size to the joining cell step sufficient to achieve sufficient bonding force of the mesh pattern layer.

21. The display device of claim 20, wherein, in an overlapping portion of the first yarn and the second yarn, a shortest distance between a top of the first yarn and a bottom of the second yarn is between 80 micrometers and 150 micrometers. ​ ​

Images