Foldable display device

Abstract

A foldable display device is provided. The foldable display device includes a folding area and non-folding areas located on both sides of the folding area, the folding area including folding shoulder areas located on both sides so as to be adjacent to the non-folding areas, and a folding central area located inside the folding shoulder areas on both sides. The foldable display device includes: a glass substrate including a first pattern disposed to correspond to a folding area; a first undercoat layer disposed on the bottom surface of the glass substrate and filled in the first pattern; the light emitting diode is arranged on the glass substrate; the packaging layer is arranged on the light emitting diode; a plurality of color filters and black matrixes disposed on the encapsulation layer; and a cover glass disposed on the plurality of color filters. Any one of the organic material layers between the plurality of color filters and the cover glass includes a second pattern disposed to correspond to the folded region.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2024-0030207 filed on February 29, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a foldable display device, and more particularly, to a foldable display device having improved rigidity, durability, and foldability. Background Art

[0004] Recently, with the advent of the information age, the field of display that visually expresses electrical information signals has been rapidly developed, and in response to this, various display devices with excellent performance such as thin thickness, light weight, and low power consumption have been developed. Specific examples of such display devices include liquid crystal display devices (LCDs), plasma display panel devices (PDPs), field emission display devices (FEDs), organic light emitting display devices (OLEDs), and the like.

[0005] Organic light-emitting display devices include an anode, a cathode, and an organic light-emitting layer disposed therebetween. However, the cathode is formed of a metal material with high reflectivity, which reflects external light, degrading the reflected luminosity and contrast. Therefore, to reduce the reflection of external light, a polarizer is placed under the cover member to absorb it. The polarizer is a film with a predetermined level of light transmittance that absorbs both external light and its reflection to suppress contrast degradation.

[0006] Meanwhile, flexible display devices, which can display images even when bent or folded like paper, have recently attracted attention as next-generation display devices. Flexible display devices are categorized into highly durable, unbreakable displays, bendable displays that can be bent without breaking, rollable displays that can be rolled, and foldable displays that can be folded. These flexible display devices offer advantages in terms of space utilization, interior design, and design, and have diverse applications.

[0007] In such flexible display devices, a structure has been proposed in which a relatively thin coated polarizing film is applied instead of a thick polarizer. However, there is a problem in that the thickness of the coated polarizing film is also large, and if the thickness is reduced, the function and display quality of the polarizing film deteriorate. Summary of the Invention

[0008] An object to be achieved by the present disclosure is to provide a foldable display device having good foldability and durability even when a glass substrate and a cover glass are used.

[0009] Another object to be achieved by the present disclosure is to provide a foldable display device for which the number of processes is reduced and the manufacturing process is simplified.

[0010] Still another object to be achieved by the present disclosure is to provide a foldable display device that suppresses cracks and peeling generated in a coating layer over a color filter due to a folding operation.

[0011] The objects of the present disclosure are not limited to the above-mentioned objects, and other objects not mentioned above can be clearly understood by those skilled in the art from the following description.

[0012] According to one aspect of the present disclosure, a foldable display device includes a folding area and non-folding areas located on both sides of the folding area, the folding area including folding shoulder areas located on both sides so as to be adjacent to the non-folding areas and a folding center area located inside the folding shoulder areas on both sides. The foldable display device includes: a glass substrate including a first pattern arranged to correspond to the folding area; a first primer layer arranged on the bottom surface of the glass substrate and filled in the first pattern; a light-emitting diode arranged on the glass substrate; an encapsulation layer arranged on the light-emitting diode; a plurality of color filters and a black matrix arranged on the encapsulation layer; and a cover glass arranged on the plurality of color filters. Any one of the organic material layers located between the plurality of color filters and the cover glass includes a second pattern arranged to correspond to the folding area. According to another aspect of the present disclosure, a foldable display device includes a folding area and non-folding areas located on both sides of the folding area, the folding area including folding shoulder areas located on both sides so as to be adjacent to the non-folding areas and a folding center area located inside the folding shoulder areas on both sides. The foldable display device includes: a glass substrate including a first pattern arranged to correspond to a folding area; a first base coating layer arranged on a bottom surface of the glass substrate and filled in the first pattern; a display panel on the glass substrate, the display panel including a light-emitting diode, a plurality of color filters and a black matrix; and a cover glass on the plurality of color filters, wherein one of the organic material layers located between the plurality of color filters and the cover glass includes a pattern corresponding to a central folding area.

[0013] Additional details of exemplary embodiments are included in the detailed description and accompanying drawings.

[0014] According to the present disclosure, the foldable display device has good foldability and durability even if a glass material is used.

[0015] According to the present disclosure, in a foldable display device, specific patterns are formed on a glass substrate, a cover glass, and an overcoat layer to improve foldability and suppress cracking and peeling of components.

[0016] According to the present disclosure, a foldable display device has a simple structure and a reduced number of manufacturing process steps to facilitate manufacturing.

[0017] According to the present disclosure, a foldable display device improves foldability and durability while operating in an inward-folding manner and an outward-folding manner simultaneously.

[0018] The effects according to the present disclosure are not limited to those exemplified above, and more various effects are included in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 is a schematic plan view of a foldable display device according to an exemplary embodiment of the present disclosure;

[0021] Figure 2 yes Figure 1 Schematic cross-sectional view of II-II';

[0022] Figure 3 yes Figure 2 A schematic cross-sectional view of a display panel;

[0023] Figure 4 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0024] Figure 5 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0025] Figure 6 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0026] Figure 7 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0027] Figure 8 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0028] Figure 9 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0029] Figure 10 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0030] Figure 11 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure;

[0031] Figure 12 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure; and

[0032] Figure 13A 1 is a diagram showing the results of a folding test simulation of the foldable display device according to Embodiment 1.

[0033] Figure 13B 1 is a diagram showing the results of a folding test simulation of the foldable display device according to Comparative Embodiment 1. DETAILED DESCRIPTION

[0034] The advantages and features of the present disclosure and methods for achieving these advantages and features will be clear by reference to the exemplary embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the exemplary embodiments disclosed herein, but will be implemented in various forms. The exemplary embodiments are provided only by way of example so that those skilled in the art can fully understand the disclosure and scope of the present disclosure.

[0035] The shapes, sizes, ratios, angles, numbers, etc. used to describe the exemplary embodiments of the present disclosure shown in the accompanying drawings are merely examples, and the present disclosure is not limited thereto. Throughout the specification, similar reference numerals generally represent similar elements. In addition, in the following description of the present disclosure, detailed descriptions of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of the present disclosure. Terms such as "including," "having," and "consisting of" used herein are generally intended to allow the addition of other components, unless these terms are used together with the term "only." Unless otherwise expressly stated, any reference to the singular may include the plural.

[0036] Even if not explicitly stated, the components are interpreted as including the ordinary error range.

[0037] When terms such as "on," "above," "below," and "beside" are used to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless these terms are used together with the terms "immediately" or "directly."

[0038] When an element or layer is referred to as being “on” another element or layer, the other layer or element can be directly on the other element or interposed therebetween.

[0039] Although the terms "first," "second," and the like are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from other components. Therefore, the first component to be mentioned below may be the second component in the technical concept of the present disclosure.

[0040] Like reference numerals generally refer to like elements throughout the specification.

[0041] The size and thickness of each component shown in the drawings are illustrated for convenience of description, and the present disclosure is not limited to the illustrated sizes and thicknesses of the components.

[0042] The features of the various embodiments of the present disclosure may be partially or completely dependent on or combined with each other, and may be technically interlocked and operated in various ways, and the embodiments may be performed independently of each other or in association with each other.

[0043] Hereinafter, a foldable display device according to exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0044] Figure 1 is a schematic plan view of a foldable display device according to an exemplary embodiment of the present disclosure. Figure 2 yes Figure 1 Schematic cross-sectional view of II-II′. Figure 3 yes Figure 2 Schematic cross-sectional view of a display panel.

[0045] Reference Figure 1 and Figure 2 The foldable display device 100 according to an exemplary embodiment of the present disclosure includes a glass substrate GS, a display panel DP, a cover glass CG, and a back panel BP. Hereinafter, for ease of description, it is assumed that the foldable display device 100 according to an exemplary embodiment of the present disclosure is an organic light-emitting display device, but is not limited thereto.

[0046] The foldable display device 100 according to an exemplary embodiment of the present disclosure can be folded at a specific angle according to the user's intention. In addition, the foldable display device can be completely folded or unfolded according to the user's intention. The foldable display device folds inward (inward folding or internal folding) to fold or unfold so that the display panel is set on the inside, and folds outward (outward folding) to fold or unfold so that the display panel is set on the outside. The foldable display device 100 according to an exemplary embodiment of the present disclosure is folded by a method selected from the user's inward folding method or the outward folding method. In addition, in one foldable display device 100, the inward folding method and the outward folding method can be implemented at the same time.

[0047] The foldable display device 100 includes a display area DA and a non-display area NDA. Furthermore, the foldable display device 100 includes a folding area FA and non-folding areas NFA1 and NFA2. Depending on whether an image is displayed, the foldable display device 100 can be divided into the display area DA and the non-display area NDA. Furthermore, depending on whether the device is folded, the foldable display device 100 can be divided into the folding area FA and the non-folding areas NFA1 and NFA2. Therefore, a portion of the foldable display device 100 can be the display area DA and the folding area FA, while another portion of the foldable display device 100 can be the non-display area NDA and the non-folding areas NFA1 and NFA2.

[0048] Meanwhile, for the sake of convenience of description, it is assumed that the foldable display device 100 according to the exemplary embodiment of the present disclosure is a foldable display device in which one folding area FA is provided only in a portion of the display area DA. However, the foldable display device 100 according to the exemplary embodiment of the present disclosure may be a display device in which a plurality of folding areas are provided in the display area DA, but is not limited thereto.

[0049] The display area DA is an area where multiple pixels are arranged to essentially display an image. Within the display area DA, multiple pixels including an emission area for displaying an image, thin-film transistors for driving the pixels, and capacitors may be provided. A pixel may include multiple sub-pixels SP. A sub-pixel SP is the smallest unit that constitutes the display area, and each sub-pixel SP may be configured to emit light of a specific wavelength band. For example, each sub-pixel SP may be configured to emit red, green, blue, or white light.

[0050] The non-display area NDA is provided to surround the display area DA. The non-display area NDA is a region in which substantially no image is displayed and in which various wirings and driver ICs for driving pixels and driver elements provided in the display area DA are provided.

[0051] As described above, the foldable display device 100 according to the exemplary embodiment of the present disclosure can be defined as a folding area FA and non-folding areas NFA1 and NFA2, depending on whether it is foldable. The foldable display device 100 includes a foldable folding area FA and non-folding areas NFA1 and NFA2 in addition to the folding area. The folding area FA is the area that folds when the foldable display device 100 is folded, and can be folded according to a specific radius of curvature relative to a folding axis. Here, the folding axis can be formed in the X-axis direction. The non-folding areas NFA1 and NFA2 can be located on both sides of the folding area FA along the folding direction. Here, the folding direction can refer to the Y-axis direction perpendicular to the folding axis. When the folding area FA is folded relative to the folding axis, the folding area FA can form a portion of a circle or an ellipse. In this case, the radius of curvature of the folding area FA can refer to the radius of the circle or ellipse formed by the folding area FA.

[0052] The folding area FA includes a central folding area CA and a shoulder folding area SA. The shoulder folding area SA is the area within the folding area FA where tension is greatest during the folding operation. The shoulder folding area SA comprises the boundary between the non-folding areas NFA1 and NFA2, which do not deform during the folding operation, and the deformed folding area FA. The central folding area CA is the area between the shoulder folding areas SA on either side of the folding area FA.

[0053] At the same time, even in Figure 1 and Figure 2 , the shoulder area SA is shown as being located within the folding area FA in contact with the non-folding areas NFA1 and NFA2. However, the present disclosure is not limited thereto. For example, the shoulder area SA may be positioned so as to overlap with the non-folding areas NFA1 and NFA2 and the folding area FA, thereby including the boundary between the non-folding areas NFA1 and NFA2 and the folding area FA.

[0054] Non-folding areas NFA1 and NFA2 are areas that remain unfolded when the foldable display device 100 is folded. That is, when the foldable display device 100 is folded, the non-folding areas NFA1 and NFA2 maintain a flat surface state. The non-folding areas NFA1 and NFA2 may extend from both sides of the folding area FA along the folding direction. In this case, the folding area FA may be defined between the non-folding areas NFA1 and NFA2. The non-folding areas NFA1 and NFA2 include a first non-folding area NFA1 and a second non-folding area NFA2. The first non-folding area NFA1 extends from one side of the folding area FA, and the second non-folding area NFA2 may extend from the other side of the folding area FA. When the foldable display device 100 is folded about the folding axis, the first non-folding area NFA1 and the second non-folding area NFA2 may overlap each other.

[0055] The glass substrate GS supports the display panel DP located thereon. The glass substrate GS may be made of plate-type alkali-free glass or non-alkali glass, but is not limited thereto.

[0056] The thickness of the glass substrate GS may be 30 to 200 μm or 50 to 150 μm. When the thickness of the glass substrate GS satisfies the above range, the glass substrate can support components of the foldable display device 100 and also enable folding or bending of the display device.

[0057] A plurality of first patterns P1 are formed on the glass substrate GS to correspond to the folding area FA. Specifically, the glass substrate GS includes an inner surface facing the display panel DP and an outer surface opposite the inner surface. In this case, the first patterns P1 may be concave patterns or grooves formed inward from the outer surface to allow the foldable display device 100 to fold or bend. The first patterns P1 may have a structure in which concave and convex portions are arranged continuously and alternately. Therefore, the first patterns P1 can provide flexibility to the glass substrate GS.

[0058] The plurality of first patterns P1 can disperse stress concentrated on the folding area FA during folding. As described above, since the plurality of first patterns P1 are formed in positions corresponding to the folding area FA, it is advantageous that the foldable display device 100 is easily foldable and has excellent elasticity.

[0059] Each of the plurality of first patterns P1 may be formed in a direction parallel to the folding axis ( Figure 1 In other words, the first pattern P1 may be formed to extend longer in the same direction as the folding axis. Therefore, the first pattern P1 may be formed to be parallel to the folding axis in a strip shape in a plan view. At the same time, the first pattern P1 may extend continuously across the display area FA to the non-display area in the same direction as the folding axis without being disconnected, but is not limited thereto. When the first pattern P1 extends parallel to the folding axis (X-axis direction), the glass substrate GS is easily bent in a direction perpendicular to the folding axis (Y-axis direction). On the contrary, due to the first pattern P1, the rigidity is increased to the folding axis direction (X-axis direction), so that the glass substrate GS is not easily bent in the folding axis direction (X-axis direction).

[0060] At the same time, Figure 2In the embodiment, a structure has been shown in which multiple first patterns P1 are formed in the folding area FA with the same shape and intervals. However, the present disclosure is not limited thereto. That is, the first patterns P1 may be formed in the folding center area CA and the folding shoulder area SA with different thicknesses, widths, and intervals. In addition, the multiple first patterns P1 may be formed in the entire folding area FA, or may be formed in only a portion of the folding area FA. That is, the multiple first patterns P1 may be formed in only a portion of the folding center area CA and the folding shoulder area SA.

[0061] Meanwhile, in the foldable display device 100 according to the exemplary embodiment of the present disclosure, the glass substrate GS may be formed from a carrier substrate or mother substrate that supports the components disposed thereon during the manufacturing process of the foldable display device 100. As will be described below, the components of the display panel are sequentially laminated onto the carrier substrate or mother substrate. After the display panel DP is fully manufactured, the carrier substrate or mother substrate is not removed, but its lower surface is etched to reduce the thickness and uniformize the surface, thereby forming the glass substrate GS. Furthermore, after etching the carrier substrate or mother substrate to uniformize the thickness or surface, a process of forming a first pattern P1 in an area corresponding to the folding area FA of the foldable display device 100 may be further added.

[0062] A first basecoat layer BC1 is disposed beneath the glass substrate GS. The first basecoat layer BC1 suppresses externally applied shocks from being transmitted to the display panel DP and prevents cracks in the glass substrate GS. Specifically, the first basecoat layer BC1 fills the first pattern P1 formed on the glass substrate GS and absorbs the folding stress generated on the glass substrate GS during the folding operation, thereby improving foldability. Therefore, the combination of the glass substrate GS including the first pattern P1 and the first basecoat layer BC1 makes the foldable display device 100 easy to bend and enhances rigidity to reduce strain on the glass substrate GS. Therefore, even when the foldable display device 100 is folded with a large curvature, the strain on the glass substrate GS is reduced, preventing visible creases or stains. The first basecoat layer BC1 may include silicon or a resin material with good stretchability. For example, the first basecoat layer BC1 may include at least one selected from a polyurethane-based resin, an epoxy-based resin, a polyester-based resin, a polyether-based resin, an acrylate-based resin, an acrylonitrile-butadiene-styrene (ABS) resin, and a rubber. Specifically, the first primer layer BC1 may include at least one of phenylene, polyethylene terephthalate (PET), polyimide (PI), polyamide (PAI), polyethylene naphthalate (PEN), and polycarbonate (PC).

[0063] The back plate BP may be disposed below the glass substrate GS. The back plate BP may be bonded to the rear surface of the glass substrate GS and the first base coating layer BC1 to further support the thin display panel DP and reduce strain on the glass substrate GS during the folding operation, but may not be included if desired.

[0064] The back plate 150 may be formed of a polymer such as polyimide (PI), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl alcohol (PVA), acrylonitrile butadiene styrene (ABS), polyethylene terephthalate (PET), silicone, or polyurethane (PU), but is not limited thereto.

[0065] The first adhesive layer ADH1 is provided between the backplane BP and the first base coating layer BC1. The first adhesive layer ADH1 bonds the backplane BP to the first base coating layer BC1. The first adhesive layer ADH1 may be formed of a transparent adhesive member such as an optically clear resin (OCR) or an optically clear adhesive (OCA), but is not limited thereto. Depending on whether the backplane BP is used, the first adhesive layer ADH1 may be omitted.

[0066] The display panel DP is disposed on the glass substrate GS.

[0067] The display panel DP includes a flexible substrate, a driving thin film transistor, a display element, and the like. In the display panel DP, the flexible substrate on which the driving thin film transistor and the display element are formed is encapsulated by an encapsulation unit. The display panel DP includes a thin flexible substrate and a display element disposed on the flexible substrate to achieve flexibility.

[0068] The display element may be defined in different ways depending on the type of the display panel DP. For example, when the display panel DP is an organic light-emitting display panel DP, the display element may be an organic light-emitting diode including an anode, an emission layer, and a cathode. In addition, the display panel DP may be an inorganic light-emitting display device in which the light-emitting diode is implemented by a light-emitting diode based on an inorganic material. For example, the display panel DP may be a quantum dot display panel DP in which the light-emitting diode is implemented by quantum dots, which are self-luminous semiconductor crystals. Figure 3 The display panel DP is described in detail.

[0069] Cover glass CG is provided over the display panel DP. It protects the display panel DP from external impacts and scratches. Therefore, the cover glass CG can be formed from a transparent material with excellent impact and scratch resistance. Furthermore, the cover glass CG protects the display panel DP from moisture penetrating from the outside. Thus, the cover glass CG prevents degradation of the display panel DP, which could reduce display quality.

[0070] The thickness of the cover glass CG can be 30 μm to 90 μm. The cover glass CG having such a thickness has the advantage of excellent folding characteristics. The cover glass CG can be chemically strengthened glass. Chemically strengthened glass is glass strengthened by a chemical strengthening method. The chemical strengthening method is a process of strengthening the strength of the glass by an ion exchange method in which sodium ions contained in the glass are replaced with ions with an ion radius larger than that of the sodium ions. Ions with an ion radius larger than that of the sodium ions constituting the glass are infiltrated, thereby forming a compressive stress layer on the surface of the glass to enhance the strength. For example, chemically strengthened glass can be prepared by immersing the glass in a potassium salt solution such as potassium nitride and replacing the sodium ions of the glass with potassium ions while heating at 200°C to 450°C for a predetermined time, but is not limited thereto. 200°C to 450°C is a temperature equal to or lower than the glass transition temperature.

[0071] A protective layer PL may be provided on the cover glass CG. The protective layer PL protects the display panel DP from external impacts, scratches, or foreign matter, and suppresses scattering of fragments when the cover glass CG breaks. The protective layer PL may be a protective film. For example, the protective film may be a plastic film including one or more selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), poly(methyl methacrylate) (PMMA), polyimide (PI), polyamide-imide (PAI), polycarbonate (PC), and cycloolefin (co)polymers, but is not limited thereto.

[0072] Furthermore, the protective layer PL may be an anti-scattering layer. The anti-scattering layer may serve as a buffer layer to suppress damage to the cover glass CG due to external impact and to suppress scattering of fragments when damage occurs. For example, the anti-scattering layer may include polyurethane or a silicone-based resin that absorbs external impact and suppresses scattering of fragments when the cover glass CG breaks. The anti-scattering layer may be formed by coating the top surface of the cover glass CG with an anti-scattering coating agent.

[0073] The second adhesive layer ADH2 is provided between the cover glass CG and the display panel DP. The second adhesive layer ADH2 is bonded between the cover glass CG and the display panel DP. The second adhesive layer ADH2 may be formed of a transparent adhesive member such as an optically clear resin (OCR) or an optically clear adhesive (OCA), but is not limited thereto.

[0074] In the following, reference will be made to Figure 3 The display panel DP of the present disclosure is described in detail. Figure 3 yes Figure 2 Schematic cross-sectional view of a display panel.

[0075] Reference Figure 3The plurality of sub-pixels SP may include a first sub-pixel SP1, a second sub-pixel SP2, and a third sub-pixel SP3. The display panel DP of the foldable display device 100 according to an exemplary embodiment of the present disclosure includes a flexible substrate 110, a thin film transistor TFT, an organic light emitting diode 130, an encapsulation layer 140, a touch sensor unit 150, a plurality of color filters 170, a black matrix 180, and an overcoat layer 190.

[0076] The flexible substrate 110 is a base member for supporting the various components included in the display panel DP and can be formed of an insulating material. The flexible substrate 110 can be formed of an insulating material with a very small thickness to achieve flexibility. For example, the flexible substrate can be an insulating plastic substrate selected from polyimide, polyethersulfone, polyethylene terephthalate, and polycarbonate, but is not limited thereto. Meanwhile, in the foldable display device 100 according to the exemplary embodiment of the present disclosure, the flexible substrate can be omitted. In this case, other configurations of the display panel DP can be formed directly on the glass substrate GS located thereunder.

[0077] The first buffer layer 121 may be provided on the flexible substrate 110 to suppress the penetration of oxygen or moisture. The first buffer layer 121 may be formed as a single layer, and may also be formed in a multi-layer structure if necessary.

[0078] On the first buffer layer 121, a thin film transistor TFT including a gate electrode G, an active layer ACT, a source electrode S, and a drain electrode D is provided. The thin film transistor TFT is provided in each region of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3. Figure 3 In the embodiment, for the convenience of description, only the driving thin film transistor among the various thin film transistors that may be included in the foldable display device 100 is shown. Figure 3 , it is described as an example that the thin film transistor TFT has a coplanar structure, but the present disclosure is not limited thereto, and a thin film transistor TFT having an inverse staggered structure may also be used.

[0079] For example, an active layer ACT is provided on the first buffer layer 121, and a gate insulating layer 123 is provided on the active layer ACT to insulate the active layer ACT from the gate electrode G. Furthermore, an interlayer insulating layer 122 is provided on the first buffer layer 121 to insulate the gate electrode G from the source electrode S and the drain electrode D. The source electrode S and the drain electrode D, which are in contact with the active layer ACT, are formed on the interlayer insulating layer 122. A planarization layer 124 may be provided on the thin film transistor TFT. The planarization layer 124 planarizes the upper portion of the thin film transistor TFT. The planarization layer 124 may include a contact hole that electrically connects the thin film transistor TFT to the anode 131 of the organic light emitting diode 130.

[0080] The organic light emitting diode 130 is disposed on the planarization layer 124. For example, the organic light emitting diode 130 is formed in each of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3. Each of the organic light emitting diodes 130 includes an anode 131, an organic light emitting layer 132, and a cathode 133.

[0081] The anode 131 is disposed on the planarization layer 124. The anode 131 is disposed corresponding to each of the plurality of sub-pixels SP1, SP2, and SP3. The anode 131 is formed of a conductive material having a high work function to supply holes to the organic light-emitting layer 132. The anode 131 may be a transparent conductive layer formed of a transparent conductive oxide (TCO). For example, the anode 131 may be formed of one or more transparent conductive oxides selected from, but not limited to, indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), tin oxide (SnO2), zinc oxide (ZnO), indium copper oxide (ICO), and aluminum:zinc oxide (Al:ZnO, AZO). When the foldable display device 100 is driven as a top emission type, the anode 131 may further include a reflective layer that reflects light emitted from the light-emitting layer 132 toward the cathode 133. The anode 131 may be formed separately for each of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3.

[0082] A dam 125 is provided on the anode 131 and the planarization layer 124. The dam 125 may cover the edge of the anode 131 of the organic light-emitting diode 130 to define the emission area. In other words, the dam 125 may divide the plurality of sub-pixels SP1, SP2, and SP3. The dam 125 may be formed of an insulating material that insulates the anodes 131 of adjacent sub-pixels SP1, SP2, and SP3 from each other. Furthermore, the dam 125 may be formed of a black dam with high light absorption to suppress color mixing between adjacent sub-pixels SP1, SP2, and SP3. For example, the dam 125 may be formed of, but is not limited to, a polyimide resin, an acrylic resin, or a benzocyclobutene resin.

[0083] A cathode 133 is provided on the anode 131. The cathode 133 may be formed of a metal material having a low work function to smoothly supply electrons to the organic light emitting layer 132. For example, the cathode 133 may be formed of a metal material selected from calcium (Ca), barium (Ba), aluminum (Al), silver (Ag), and alloys including one or more thereof, but is not limited thereto. Figure 3 , the cathode is formed as a layer on the anode 131. That is, the cathode 133 can be formed as a single layer in the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3. When the foldable display device 100 is driven as a top emission type, the cathode 133 can be formed to have a very small thickness to be substantially transparent.

[0084] An organic light-emitting layer 132 is provided between the anode 131 and the cathode 133. The organic light-emitting layer 132 is a layer in which electrons and holes couple to emit light. The organic light-emitting layer of the first sub-pixel SP1 is a red organic light-emitting layer, the organic light-emitting layer of the second sub-pixel SP2 is a green organic light-emitting layer, and the organic light-emitting layer of the third sub-pixel SP3 is a blue organic light-emitting layer.

[0085] To improve the luminous efficiency of the organic light-emitting diode 130, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer may also be included. For example, the hole injection layer and the hole transport layer may be disposed between the anode 131 and the organic light-emitting layer 132, and the electron transport layer and the electron injection layer may be disposed between the organic light-emitting layer 132 and the cathode 133. In addition, a hole blocking layer or an electron blocking layer may be provided to further improve the recombination efficiency of holes and electrons in the organic light-emitting layer 132.

[0086] An encapsulation layer 140 is provided on the organic light emitting diode 130. The encapsulation layer 140 may cover the organic light emitting diode 130. The encapsulation layer 140 may protect the organic light emitting diode 130 from moisture, oxygen and external impact. The encapsulation layer 140 may be formed in a multilayer structure in which an inorganic layer formed of an inorganic insulating material and an organic layer formed of an organic material are laminated. For example, the encapsulation layer 140 may be composed of at least one organic layer and at least two inorganic layers, and have a multilayer structure in which the inorganic layer and the organic layer are alternately laminated, but is not limited thereto. For example, the encapsulation layer 140 may have a three-layer structure including a first inorganic layer 141, an organic layer 142, and a second inorganic layer 143. In this case, the first inorganic layer 141 and the second inorganic layer 143 may be independently formed of one or more selected from silicon nitride (SiNx), silicon oxide (SiOx), aluminum oxide (AlOx) and silicon oxynitride (SiON), but is not limited thereto. For example, the organic layer 142 may be formed of one or more selected from epoxy, polyimide, polyethylene, and silicon oxycarbide (SiOC), but is not limited thereto.

[0087] The touch sensor unit 150 is disposed on the encapsulation layer 140 to provide the foldable display device 100 with touch sensing functionality. The foldable display device 100 according to an exemplary embodiment of the present disclosure includes the touch sensor unit 150, which has a structure in which touch electrodes 151 are formed on the encapsulation layer 140, rather than the structure of a conventional touch panel in which touch electrodes are formed on a separate base member and then disposed above an organic light-emitting diode via an adhesive member. Since the touch sensor unit 150 is formed directly on the encapsulation layer 140, the adhesive member that bonds the touch sensor unit 150 to the organic light-emitting display panel DP is omitted, thereby reducing the thickness of the foldable display device 100.

[0088] The touch sensor unit 150 includes a touch electrode 151 and a touch protection layer 152. The touch electrode 151 can be formed directly on the encapsulation layer 140 without using an adhesive member. The touch electrode 151 is an electrode that senses touch input and can be composed of a sensing electrode and a drive electrode, and can detect touch coordinates by sensing changes in capacitance between the sensing electrode and the drive electrode. For example, the drive electrode is provided on the second inorganic layer 143, and the sensing electrode can be provided on the same planar surface as the drive electrode. As another example, a touch insulating layer is provided on the drive electrode, and the sensing electrode can be provided on the touch insulating layer. The placement of the touch electrode 151 is not limited thereto and can vary as needed.

[0089] Touch electrode 151 is formed directly on encapsulation layer 140, making the distance between organic light-emitting diode 130 and touch electrode 151 too close. This generates parasitic capacitance between touch electrode 151 and an electrode included in organic light-emitting diode 130 or thin-film transistor TFT. As a result, touch sensitivity may be reduced. Therefore, the thickness of encapsulation layer 140 can be appropriately adjusted to minimize parasitic capacitance.

[0090] The touch electrode 151 may be formed of a transparent metal material that transmits light, such as indium tin oxide (ITO) or indium zinc oxide (IZO). The touch electrode 151 may have various shapes, such as a rectangular shape, an octagonal shape, a circular shape, or a diamond shape.

[0091] The touch protection layer 152 is disposed on the touch electrode 151. The touch protection layer 152 suppresses short circuit or damage of the touch electrode 151 and flattens the upper surface of the touch electrode 151. The touch protection layer 152 may be formed of a transparent insulating resin such as an acrylic resin, a polyester resin, an epoxy resin, or a silicon resin.

[0092] At the same time, Figure 3, a structure in which the touch electrodes 151 of the touch sensor unit 150 directly contact the encapsulation layer 140 is disclosed, but the present invention is not limited thereto. For example, a touch buffer layer may be provided between the encapsulation layer 140 and the touch sensor unit 150, and the touch electrodes 151 may be provided on the touch buffer layer. The touch buffer layer can prevent damage to the encapsulation layer 140 and the organic light-emitting diode 130 during the process of forming the touch electrodes 151 directly on the encapsulation layer 140.

[0093] The touch buffer layer can be formed of an inorganic material with excellent barrier properties. Therefore, the penetration of moisture or oxygen can be minimized. For example, the touch buffer layer can be formed of an inorganic material such as silicon nitride (SiNx), silicon oxide (SiOx), or aluminum oxide (AlOx), but is not limited thereto.

[0094] The second buffer layer 160 is provided on the touch sensor unit 150. The second buffer layer 160 inhibits moisture or oxygen from penetrating from the outside to protect the components of the foldable display device 100. The second buffer layer 160 can be formed of an inorganic material with excellent barrier properties. Therefore, the penetration of moisture or oxygen can be minimized. For example, the second buffer layer 160 can be formed of one or more inorganic materials selected from silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiON) and aluminum oxide (Al2O3), but is not limited thereto. In addition, the second buffer layer 160 can compensate for the deterioration of the adhesion between the multiple color filters 170 and the black matrix 180 and the touch protection layer 152. That is, the second buffer layer 160 is provided on the touch protection layer 152 to bond the multiple color filters 170 and the black matrix 180 to the touch protection layer 152. When the touch sensor unit 150 is provided above or below the encapsulation layer 140 by means of an adhesive member, the second buffer layer 160 can be omitted. A plurality of color filters 170 and a black matrix 180 are disposed on the second buffer layer 160. The plurality of color filters 170 and the black matrix 180 are integrally formed on the same planar surface and absorb external light to minimize degradation of visibility and contrast of the foldable display device 100 due to external light.

[0095] A plurality of color filters 170 and a black matrix 180 are disposed on the second buffer layer 160. The plurality of color filters 170 and the black matrix 180 may function as an anti-reflection layer that absorbs external light to minimize degradation of visibility and contrast of the foldable display device 100 due to external light.

[0096] The black matrix 180 can be provided on the touch sensor unit 150 or the second buffer layer 160. The black matrix 180 is provided along the boundaries of the sub-pixels and includes openings that open the sub-pixels. The black matrix 180 divides each of the plurality of color filters 170. The black matrix 180 can be provided to overlap with the bank 125. Thus, color mixing between the sub-pixels SP1, SP2, and SP3 can be minimized. In addition, the black matrix 180 absorbs external light. Therefore, degradation of the visibility and contrast of the foldable display device 100 caused by external light can be minimized.

[0097] A plurality of color filters 170 are provided on the encapsulation layer 140. The plurality of color filters 170 may be provided on the touch sensor unit 150 or the second buffer layer 160. In addition, the plurality of color filters 170 are provided in direct contact with the second buffer layer 160 and may be provided to cover a portion of the black matrix 180. The plurality of color filters 170 absorb external light to minimize the degradation of visibility and contrast caused by external light and improve color reproducibility. The plurality of color filters 170 are provided on the encapsulation layer 140 to improve luminous efficiency and omit a polarizer or polarizing film.

[0098] The plurality of color filters 170 are arranged to correspond to the sub-pixels arranged thereunder. Figure 3 The plurality of color filters 170 include a first color filter 171 corresponding to the first sub-pixel SP1, a second color filter 172 corresponding to the second sub-pixel SP2, and a third color filter 173 corresponding to the third sub-pixel SP3. When the first sub-pixel SP1 is a red sub-pixel, the first color filter 171 is a red color filter. In addition, when the second sub-pixel SP2 is a green sub-pixel, the second color filter 172 is a green color filter, and when the third sub-pixel SP3 is a blue sub-pixel, the third color filter 173 is a blue color filter.

[0099] Since each color filter 170 is provided to correspond to the color of each corresponding sub-pixel SP1, SP2, SP3, internal light emitted from each of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3 passes through the color filter 170. For example, red light emitted from the first sub-pixel SP1 passes through the first color filter 171. In contrast, when external light is incident, the external light corresponding to the absorption wavelength of the coloring material included in each color filter 170 is absorbed by the color filter 170. The external light not absorbed by the color filter 170 is reflected from the cathode 133 to pass through the color filter 170 again. The reflected light corresponding to the absorption wavelength of the coloring material included in each color filter 170 is absorbed by the color filter 170. Therefore, the degradation of display quality caused by external light can be minimized.

[0100] The overcoat layer 190 is provided to cover the plurality of color filters 170 and the black matrix 180. The overcoat layer 190 may planarize upper portions of the plurality of color filters 170 and the black matrix 180. For example, the overcoat layer 190 may be formed of a transparent resin such as an acrylic resin, a silicon resin, a polyester resin, and an epoxy resin, but is not limited thereto.

[0101] At the same time, the outer coating 190 may include a UV absorbing layer. The UV absorbing layer blocks light with ultraviolet wavelengths from the external light incident on the foldable display device 100. The UV absorbing layer blocks light with a wavelength equal to or less than 400 nm and transmits visible light with a wavelength exceeding about 400 nm. The UV absorbing layer may be formed of an organic material including a UV blocker or UV absorber that blocks or absorbs light with a wavelength equal to or less than 400 nm. The UV blocker or UV absorber may be used without limitation as long as the UV blocker or UV absorber is a material used in the art.

[0102] Reference Figure 2 The outer coating layer 190 includes a plurality of second patterns P2 so as to correspond to the folding shoulder area SA of the folding area FA of the foldable display device 100. The plurality of second patterns P2 reduce the folding stress applied to the outer coating layer 190 during the folding operation and improve the adhesion between the outer coating layer 190 and the second adhesive layer to suppress peeling and cracks generated on the outer coating layer 190.

[0103] The second pattern P2 may be an opening pattern or a hole formed by penetrating the outer coating layer 190 in the thickness direction. When the foldable display device 100 is folded, stress is concentrated on the folding area FA. The second pattern P2 can disperse the stress concentrated on the folding area FA of the outer coating layer 190 during folding.

[0104] Each of the plurality of second patterns P2 may be formed in a direction parallel to the folding axis ( Figure 1 In other words, the second pattern P2 may be formed to extend long in the same direction as the folding axis. Therefore, in a plan view, the second pattern P2 may be formed in the form of stripes parallel to the folding axis.

[0105] At the same time, Figure 2In the embodiment, a structure is shown in which multiple second patterns P2 are formed in the folding area FA with the same shape and intervals, but the present disclosure is not limited thereto. That is, the second patterns P2 may be formed in the folding center area CA and the folding shoulder area SA with different thicknesses, widths, and intervals. In addition, the multiple second patterns P2 may be formed in the entire folding area FA or only in a portion of the folding area FA. That is, the multiple second patterns P2 may be formed only in the folding center area CA and the folding shoulder area SA.

[0106] Meanwhile, the plurality of second patterns P2 may have a shape corresponding to the first pattern P1 of the glass substrate GS. Figure 2 , the plurality of second patterns P2 may be arranged to overlap with the first patterns P1 of the glass substrate GS. However, the present disclosure is not limited thereto, and the plurality of second patterns P2 may be formed to have a shape opposite to the plurality of first patterns P1 of the glass substrate GS. For example, the plurality of second patterns P2 of the overcoat layer 190 may have an open shape, and the plurality of first patterns P1 of the glass substrate GS may have grooves or recesses. In this case, the open areas of the overcoat layer 190 may correspond to the recesses of the glass substrate GS in the vertical direction (Z-axis direction).

[0107] The foldable display device according to the exemplary embodiment of the present disclosure can reduce the folding stress applied to the foldable display device 100 by means of the multiple first patterns P1 formed on the glass substrate GS and the multiple second patterns P2 formed on the overcoat layer 190. Furthermore, rather than using multiple plates to ensure folding performance and rigidity as in conventional foldable display devices, a mother substrate or carrier substrate is used as the base substrate, as this ensures the number of processes and economic feasibility. Specifically, when using the glass substrate GS and the cover glass CG, both limited foldability and durability are satisfied.

[0108] Figure 4 is a schematic cross-sectional view of a foldable display device according to another exemplary embodiment of the present disclosure. Figure 4 The foldable display device 200 shown has Figures 1 to 3 The foldable display device 100 shown has substantially the same configuration except for the shapes of the first pattern P1 formed on the glass substrate GS and the second pattern P2 formed on the overcoat layer 290. Therefore, redundant description will be omitted.

[0109] Reference Figure 4 , the first pattern P1 formed on the glass substrate GS may be formed in the folding center area CA and the folding shoulder area SA with different thicknesses, widths, and intervals. Figure 4The thickness of the first pattern P1 in the shoulder area SA is smaller than that in the central fold area CA. During the folding operation, the glass substrate GS is subjected to strong compressive stress in the shoulder area SA, which can cause cracks and delamination. Therefore, the thickness of the first pattern P1 in the shoulder area SA is formed to be smaller than that in the central fold area CA to improve durability against compressive stress while maintaining foldability. Furthermore, the thickness of the first pattern P1 in the shoulder area SA gradually decreases as it approaches the non-folding areas NFA1 and NFA2.

[0110] Furthermore, the width of and spacing between the first patterns P1 in the shoulder area SA can be smaller than the width of and spacing between the first patterns P1 in the central fold area CA. As described above, the glass substrate GS in the shoulder area SA is subjected to strong compressive stress during the folding operation, resulting in a denser arrangement of the width and spacing of the first patterns P1 in the shoulder area SA. This reduces the folding stress on the glass substrate GS in the shoulder area SA, improving durability. Furthermore, the width and spacing of the first patterns P1 in the shoulder area SA gradually decrease as they approach the non-folding areas NFA1 and NFA2, allowing for a denser pattern.

[0111] Next, in Figure 2 In the foldable display device 100 shown, the second pattern P2 formed in the overcoat layer 190 is formed in the entire folding area FA. Figure 4 In the illustrated foldable display device 200, the second pattern P2 may be formed only in the folding shoulder region SA. As described above, during the folding operation, the components of the foldable display device 200 are subjected to particularly strong compressive stress in the folding shoulder region SA. In the outer coating 290, compressive stress is also concentrated in the folding shoulder region SA. The second pattern P2 can disperse the stress concentrated in the folding shoulder region FA of the outer coating 290 during folding.

[0112] The plurality of second patterns P2 may have a shape arranged to alternate with the first patterns P1 of the glass substrate GS. Specifically, the plurality of second patterns P2 of the overcoat layer 290 may be formed to have a shape opposite to the plurality of first patterns P1 of the glass substrate GS. Figure 4, the plurality of second patterns P2 of the outer coating layer have an open shape, and the plurality of first patterns P1 of the glass substrate GS have grooves or recesses. In this case, the open area of ​​the outer coating layer 290 may correspond to the convex portion of the glass substrate GS in the vertical direction (Z axis direction). In other words, the portion of the outer coating layer 290 that remains unopened by the second pattern P2 may correspond to the groove or recess formed by the first pattern P1 of the glass substrate GS. Figure 4 In the foldable display device 200 shown, when the first pattern P1 of the glass substrate GS and the second pattern P2 of the overcoat layer 290 are alternately arranged, the complementary structure between the first pattern P1 and the second pattern P2 reduces stress during folding and improves the flatness of the entire display panel. This improves durability.

[0113] Figure 5 is a schematic cross-sectional view of a foldable display device according to yet another exemplary embodiment of the present disclosure. Figure 5 The foldable display device 300 shown has Figure 4 The foldable display device 200 shown has substantially the same configuration except for the shapes of the first pattern P1 formed on the glass substrate GS and the second pattern P2 formed on the overcoat layer 390. Therefore, redundant description will be omitted.

[0114] Reference Figure 5 The first pattern P1 formed on the glass substrate GS can form a groove across the entire folding area FA. Specifically, the first pattern P1 can be a groove having a concave shape extending from the outer surface to the inner surface of the glass substrate GS. The first pattern P1 can be formed with a stepped shape that gradually deepens from the area adjacent to the non-folding areas NFA1 and NFA2 toward the center of the folding area FA. In other words, the first pattern P1 forms a step in the folding area FA, and the depth of the groove of the first pattern P1 in the folding shoulder area SA gradually increases as it approaches the central folding area CA.

[0115] At the same time, the second pattern P2 formed in the outer coating 390 may also form a groove across the entire folding area FA. The second pattern P2 may be a groove that is recessed from the top surface to the bottom surface of the outer coating 390. The second pattern P2 may have a shape opposite to the first pattern P1. That is, the second pattern P2 may be formed with a stepped shape that gradually becomes shallower from the area adjacent to the non-folding areas NFA1 and NFA2 toward the center of the folding area FA. The second pattern P2 forms a step in the folding area FA, and the depth of the groove of the second pattern P2 in the folding shoulder area SA gradually decreases as it approaches the folding center area CA. In other words, the second pattern P2 has a stepped shape that deepens toward the non-folding areas NFA1 and NFA2.

[0116] At this time, the stepped shape of the first pattern P1 formed in the glass substrate GS may correspond to the stepped shape of the second pattern P2 formed in the overcoat layer 390. That is, even if the depths of the patterns are different, the stepped portion formed by the first pattern P1 may coincide with the step of the overcoat layer formed by the second pattern in the vertical direction (Z-axis direction).

[0117] exist Figure 5 In the illustrated foldable display device 300, the first pattern P1 formed in the glass substrate GS has a concave shape that has a stepped shape across the folding area FA, making the glass substrate GS easier to fold. However, there is a possibility that the durability of the glass substrate GS may be reduced due to the first pattern P1. Therefore, the second pattern P2 formed in the overcoat layer 390 has a stepped shape with a concave and convex shape opposite to that of the first pattern P1 to compensate for the etching of the glass substrate GS by the first pattern P1. This improves durability.

[0118] Figure 6 is a schematic cross-sectional view of a foldable display device according to yet another exemplary embodiment of the present disclosure. Figure 6 The foldable display device 400 shown has Figure 4 The foldable display device 200 shown has substantially the same configuration except that the third pattern P3 is formed on the cover glass CG and the second base coating layer BC2 is formed under the cover glass CG. Therefore, redundant description will be omitted.

[0119] Reference Figure 6 A third pattern P3 is formed on the cover glass CG. The third pattern P3 may be a concave pattern or groove formed from the bottom surface to the top surface to allow the foldable display device 400 to fold inward. The third pattern P3 may have a structure in which concave and convex portions are arranged continuously and alternately. Therefore, the third pattern P3 can impart flexibility to the cover glass CG.

[0120] The plurality of third patterns P3 can disperse stress concentrated on the folding area FA during folding. As described above, since the plurality of third patterns P3 are formed in positions corresponding to the folding area FA, the foldable display device 400 is easy to fold and has excellent elasticity.

[0121] Meanwhile, the third pattern P3 may have the same shape as the first pattern P1 of the glass substrate GS. Therefore, the same description as the first pattern P1 is omitted. Meanwhile, the third pattern P3 may be formed to substantially correspond to the first pattern P1.

[0122] At the same time, a second base coating layer BC2 is provided beneath the cover glass CG. The second base coating layer BC2 suppresses the transmission of externally applied impacts to the display panel DP and suppresses cracks in the cover glass CG. Specifically, the second base coating layer BC2 fills the third pattern P3 formed on the cover glass CG and absorbs the folding stress generated on the cover glass CG during the inner folding operation, thereby improving foldability. Therefore, the combination of the cover glass CG including the third pattern P3 and the second base coating layer BC2 allows the foldable display device 400 to be easily bent and enhances rigidity to reduce strain on the cover glass CG.

[0123] The material configuring the second base coating layer BC2 is substantially the same as the material configuring the first base coating layer BC1, and thus redundant description will be omitted.

[0124] Figure 6 The illustrated foldable display device 400 forms a plurality of third patterns P3 having a concave shape not only on the glass substrate GS but also on the cover glass CG to further improve the foldability of the foldable display device 100 .

[0125] Figure 7 is a schematic cross-sectional view of a foldable display device according to yet another exemplary embodiment of the present disclosure. Figure 7 The foldable display device 500 shown has Figure 6 The foldable display device 400 shown has a substantially identical configuration, except that the second base coating layer BC2 is not provided and the structures of the cover glass CG and the second adhesive layer ADH2 are changed. Therefore, redundant description will be omitted.

[0126] Reference Figure 7 , the cover glass CG includes a third pattern P3. At this time, the shape of the third pattern P3 located in the folding central area CA is the same as that of the third pattern P3. Figure 6 The third pattern of the foldable display device 400 shown has the same shape. That is, compared to the adjacent non-folding areas NFA1 and NFA2, the third pattern P3 located in the folding center area CA may be a concave pattern or groove formed from the bottom to the top surface of the cover glass CG. However, the third pattern P3 located in the folding shoulder area SA has a concave portion formed from the bottom to the top surface of the cover glass CG and a convex portion protruding from the bottom surface of the cover glass CG toward the display panel DP. The convex portion can be inserted into the second adhesive layer ADH2 located thereunder.

[0127] The second adhesive layer ADH2 is disposed between the cover glass CG and the display panel DP. At this point, the second adhesive layer ADH2 may fill the third pattern P3 of the cover glass CG. That is, the second adhesive layer ADH2 may fill the recessed portion of the cover glass CG formed by the third pattern P3. As described above, the convex portion formed by the third pattern P3 has a shape that protrudes from the cover glass CG toward the display panel to be inserted into the second adhesive layer ADH2. The second adhesive layer ADH2 may have a pattern formed by the convex portion of the cover glass CG, which extends to the second adhesive layer ADH2.

[0128] Figure 7 The foldable display device 500 shown includes concave and convex portions formed by the third pattern P3 of the cover glass CG, and the second adhesive layer ADH2 provided below the cover glass CG fills the concave portions of the cover glass CG. Therefore, the second primer layer can be omitted. By doing so, the number of processes for the foldable display device 400 is reduced and its thickness can be reduced. In addition, an additional pattern is formed in the second adhesive layer ADH2 below which the convex portion of the cover glass CG is located, so that the second adhesive layer ADH2 can be replaced with the second adhesive layer ADH2. Figure 6 The second pattern is formed in the outer coating layer in the foldable display device 400 shown. By doing so, a separate process for forming the second pattern on the outer coating layer 590 can be omitted, so that the number of manufacturing processes of the foldable display device 500 can be reduced.

[0129] Figure 8 is a schematic cross-sectional view of a foldable display device according to yet another exemplary embodiment of the present disclosure. Figure 8 The foldable display device 500 shown has Figure 6 The foldable display device 400 shown has a substantially identical configuration, except that the second pattern P2 formed on the overcoat layer 690 and the third pattern P3 formed on the cover glass CG have different shapes, and a top coating layer BC3 is provided instead of the second base coating layer. Therefore, redundant descriptions will be omitted.

[0130] Reference Figure 8 A third pattern P3 is formed on the cover glass CG. The third pattern P3 may be a concave pattern or groove formed from the top surface of the cover glass CG toward the display panel DP to allow the foldable display device to fold outward. The third pattern P3 may have a structure in which concave and convex portions are arranged continuously and alternately. Therefore, the third pattern P3 can impart flexibility to the cover glass CG.

[0131] When the foldable display device 600 is folded outward, the plurality of third patterns P3 can disperse the stress concentrated on the folding area FA. During the outward folding operation of the foldable display device 600, unlike the inward folding operation, the maximum compressive stress is applied to the folding center area CA in both the cover glass CG and the outer coating 690. In other words, when the foldable display device 600 is folded outward, the maximum tension is applied to the top surface of the cover glass CG located on the outside, resulting in grooves formed on the top surface of the cover glass CG to reduce the stress in the folding center area CA.

[0132] Meanwhile, the third pattern P3 can have the same shape as the first pattern P1 of the glass substrate GS, except for the groove formation direction. Therefore, the description of the same as the first pattern P1 is omitted. Meanwhile, the third pattern P3 can be formed to substantially correspond to the first pattern P1. Meanwhile, during the outward folding operation of the foldable display device 600, in the case where the patterns contact each other according to the curvature radius, the ends of the patterns can be implemented to be rounded or sharply angled.

[0133] At the same time, a top coating layer BC3 is provided above the cover glass CG. The top coating layer BC3 suppresses the transmission of externally applied shock to the display panel DP and prevents cracks in the cover glass CG. Specifically, the top coating layer BC3 fills the third pattern P3 formed on the cover glass CG and absorbs the folding stress generated on the cover glass CG during the external folding operation, thereby improving foldability. Therefore, the combination of the cover glass CG including the third pattern P3 and the top coating layer BC3 allows the foldable display device 600 to be easily bent and enhances rigidity to reduce strain on the cover glass CG.

[0134] Reference Figure 8 The outer coating layer 690 includes a plurality of second patterns P2 corresponding to the folded central area SA. The plurality of second patterns P2 reduce the folding stress applied to the outer coating layer 690 during the outer folding operation and improve the adhesion between the outer coating layer 690 and the second adhesive layer ADH2 to suppress peeling and cracks generated on the outer coating layer 690.

[0135] As described above, during the outward folding operation of the foldable display device 600, unlike the inward folding operation, the outer coating 690 is located above the neutral plane, thereby applying the maximum compressive stress in the folding center area CA. Therefore, the opening pattern is formed in the folding center area CA, rather than in the folding shoulder area SA, so that the stress concentrated in the folding center area CA of the outer coating 690 can be dispersed.

[0136] Meanwhile, the plurality of second patterns P2 may have shapes corresponding to the first pattern P1 of the glass substrate GS and the third pattern P3 of the cover glass CG. Specifically, the plurality of second patterns P2 of the overcoat layer 690 may be formed to have the same shapes as the first pattern P1 and the third pattern P3. Figure 8 The second patterns P2 of the overcoat layer 690 have an open shape, and the first patterns P1 of the glass substrate GS and the third patterns P3 of the cover glass CG form a groove. In this case, the opening area of ​​the overcoat layer 690 corresponds to the groove in the vertical direction (Z axis direction) of the glass substrate GS and the cover glass CG.

[0137] Figure 8 The illustrated foldable display device 600 changes the shapes of the third pattern P3 of the cover glass CG and the second pattern P2 of the overcoat layer 690 to suppress cracks and peeling of the cover glass CG and the overcoat layer 690 even during an outward folding operation.

[0138] Figure 9 is a schematic cross-sectional view of a foldable display device according to yet another exemplary embodiment of the present disclosure. Figure 9 The foldable display device 700 shown has Figure 8 The foldable display device 600 shown has a substantially identical configuration, except that the structures of the cover glass CG, the top coating BC3, the overcoat layer 790, and the second adhesive layer ADH2 are changed. Therefore, redundant descriptions will be omitted.

[0139] Reference Figure 9 , the cover glass CG includes a third pattern P3. At this time, the shape of the third pattern P3 located in the folded shoulder area SA is the same as that of the third pattern P3. Figure 8 The third pattern P3 of the foldable display device 600 shown has the same shape. For example, the third pattern P3 located in the fold shoulder area SA may be a concave pattern or groove formed inward from the top surface of the cover glass CG toward the display panel DP. However, the third pattern P3 located in the fold center area CA may be an opening pattern or hole that passes through the cover glass CG.

[0140] Meanwhile, the second adhesive layer ADH2 disposed under the cover glass CG includes a fourth pattern P4. The fourth pattern P4 may be an opening pattern or a hole passing through the second adhesive layer ADH2. The fourth pattern P4 of the second adhesive layer ADH2 may overlap with the third pattern P3 of the cover glass CG to form a hole.

[0141] The top coating layer BC3 is provided on the cover glass CG. The top coating layer BC3 suppresses the transmission of external impact to the display panel DP and suppresses cracks in the cover glass CG. At this time, the top coating layer BC3 may be filled in both the third pattern P3 of the cover glass CG and the fourth pattern P4 of the second adhesive layer ADH2.

[0142] Figure 9 The foldable display device 700 shown forms a hole that is formed to overlap with the cover glass CG and the second adhesive layer ADH2 to form a third pattern P3 and a fourth pattern P4. Figure 8 Compared to the foldable display device 600 shown in FIG. , the fourth pattern P4 formed on the second adhesive layer ADH2 can replace the second pattern formed on the overcoat layer. Specifically, the third pattern P3 of the cover glass CG and the fourth pattern P4 of the second adhesive layer ADH2 can be simultaneously etched in a single process prior to the process of bonding the display panel DP and the cover glass CG. In other words, by forming the third pattern P3 and the fourth pattern P4 simultaneously, a separate process for forming the second pattern on the overcoat layer 790 can be omitted, thereby reducing the number of manufacturing processes for the foldable display device 600.

[0143] Figure 10 is a schematic cross-sectional view of a foldable display device according to yet another exemplary embodiment of the present disclosure. Figure 10 The foldable display device 800 shown has Figure 9 The foldable display device 700 shown has substantially the same configuration except that the etch stop layer ESL is disposed below the second adhesive layer ADH2 , and thus redundant description will be omitted.

[0144] Reference Figure 10 The etch stop layer ESL is disposed below the second adhesive layer ADH2. The etch stop layer ESL suppresses damage to the display panel DP disposed below the etch stop layer ESL caused by the etching process during the etching process of forming the third pattern on the cover glass CG and the fourth pattern on the second adhesive layer. The etch stop layer ESL may be formed of an inorganic material such as silicon oxide (SiO2), but is not limited thereto.

[0145] Figure 10The foldable display device 800 shown is an external foldable display device, such that the foldable display device 800 includes a third pattern P3 on the cover glass CG. The third pattern P3 is a concave pattern or groove formed inward from the top surface of the cover glass CG toward the display panel DP. According to the manufacturing process of the foldable display device 800, the thin-film transistor TFT, the organic light-emitting diode 130, the plurality of color filters 170, the black matrix 180, and the overcoat layer 790 are sequentially formed on a mother substrate or a carrier substrate. Thereafter, the cover glass CG is directly coupled to the overcoat layer 790 using a second adhesive layer ADH2. Finally, the top surface of the cover glass CG is etched to reduce the thickness of the cover glass CG and form the third pattern P3 and the fourth pattern P4. However, during the process of forming the fourth pattern P4 in the shape of a hole passing through the second adhesive layer ADH2, components located below the second adhesive layer ADH2, such as the plurality of color filters 170 and the overcoat layer 790, are also etched or damaged. Therefore, the etch stop layer ESL is formed on the overcoat layer 790 to protect the display panel under the second adhesive layer ADH2 and improve process convenience.

[0146] Figure 11 is a schematic cross-sectional view of a foldable display device according to yet another exemplary embodiment of the present disclosure. Figure 11 The foldable display device 900 shown may be a foldable display device 900 including a plurality of folding areas FA to achieve multi-folding, and the plurality of folding areas may be folded simultaneously through the multi-folding. Figure 11 The foldable display device 900 shown has Figure 6 The foldable display device 400 shown has a substantially identical configuration, except that the folding area FA includes a first folding area FA1 and a second folding area FA2, and the first pattern P1 formed on the glass substrate GS, the second pattern P2 formed on the overcoat layer 990, and the third pattern P3 formed on the cover glass CG are arranged in the first folding area FA1 and the second folding area FA2 to form two groups. Therefore, redundant descriptions will be omitted.

[0147] Reference Figure 11 , the foldable display device 900 includes a first non-folding area NFA1, a first folding area FA1, a second non-folding area NFA2, a second folding area FA2 and a third non-folding area NFA3 sequentially positioned along the folding direction (X-axis direction). Figure 11 The foldable display device 900 may be operated by an inward folding operation such that the display panel DP is folded or unfolded to be disposed inside the first folding area FA1 and the second folding area FA2.

[0148] The glass substrate GS includes a first pattern P1 formed in each of the first folding area FA1 and the second folding area FA2. The overcoat layer 990 includes a second pattern P2 formed in each of the first folding area FA1 and the second folding area FA2, and the cover glass CG includes a third pattern P3 formed in the first folding area FA1 and the second folding area FA2. The description of the first pattern P1, the second pattern P2, and the third pattern P3 is the same as that already described. Figure 6 The description of the first pattern P1, the second pattern P2 and the third pattern P3 described in the above is basically the same. Therefore, redundant description will be omitted. Figure 11 The first pattern P1, the second pattern P2 and the third pattern P3 are shown in FIG. Figure 6 The first pattern P1, the second pattern P2, and the third pattern P3 in the foldable display device 400 are shown to be the same, but the present disclosure is not limited thereto. That is, according to the exemplary embodiment described in the present disclosure, the pattern shapes, i.e. Figure 2 、 Figure 4 、 Figures 6 to 10 The illustrated first pattern P1 , second pattern P2 , and third pattern P3 are selectively applied to the foldable display device 900 .

[0149] exist Figure 11 In the illustrated foldable display device 900, first, second, and third patterns P1, P2, and P3 are formed on each of the glass substrate GS, overcoat layer 990, and cover glass CG in each of the multiple folding areas FA1 and FA2, enhancing foldability and durability. Specifically, rather than using multiple substrates to ensure folding performance and rigidity, as in conventional foldable display devices, a mother substrate or carrier substrate is used as the base substrate, minimizing the number of process steps and ensuring economic feasibility. Specifically, even with the glass substrate GS and cover glass CG, limited foldability can be achieved.

[0150] Figure 12 is a schematic cross-sectional view of a foldable display device 1000 according to yet another exemplary embodiment of the present disclosure. Figure 12 The foldable display device 1000 shown may include multiple folding areas FA1 and FA2 to achieve multi-folding. The multiple folding areas are folded simultaneously through multi-folding. In this case, in the first folding area FA1, the foldable display device operates in an inward folding mode, such that the display panel DP is folded or unfolded to be positioned inward. In the second folding area FA2, the foldable display device operates in an outward folding mode, such that the display panel DP is folded or unfolded to be positioned outward.

[0151] exist Figure 12In the foldable display device 1000 shown, patterns of different shapes are formed in the first folding area FA1 and the second folding area FA2 in the glass substrate GS, the overcoat layer 1090 and the cover glass CG.

[0152] Reference Figure 12 In the first folding area FA1, the glass substrate GS, the outer coating 1090 and the cover glass CG form a pattern that reduces the strong folding stress applied to the folding shoulder area SA during the inner folding and suppresses the peeling and cracking of the component. Specifically, in the first folding area FA1, the pattern as shown above is formed. Figure 6 The first pattern P1, the second pattern P2, and the third pattern P3 described. That is, the glass substrate GS includes a first pattern P1 having a groove shape formed from the bottom surface toward the display panel DP. In addition, the outer coating layer 1090 includes a second pattern P2 having a hole shape formed only in the folding shoulder area SA. In addition, the cover glass CG includes a third pattern P3 having a groove shape formed from the bottom surface toward the display panel DP. At this time, the first base coating layer BC1 and the second base coating layer BC2 are respectively arranged under the glass substrate GS and the cover glass CG to fill in the first pattern P1 and the third pattern P3. Through this configuration, when the first folding area FA1 is operated in an inward folding manner, the folding stress applied to the first folding area FA1 is reduced, and the durability of the display device can be improved.

[0153] Next, in the second folding area FA2, the glass substrate GS, the overcoat layer 1090, and the cover glass CG form a pattern that reduces the strong folding stress applied to the folding center area CA during the inner folding and suppresses peeling and cracking of the components. Specifically, in the second folding area FA2, the pattern as shown above is formed. Figure 7 The first pattern P1, the second pattern P2 and the third pattern P3 described. That is, the glass substrate GS includes a first pattern P1 having a groove shape formed from the bottom surface toward the display panel DP. In addition, the outer coating layer 1090 includes a second pattern P2 having a hole shape formed only in the folding central area CA. In addition, the cover glass CG includes a third pattern P3 having a groove shape formed from the top surface toward the display panel DP. At this time, the first base coating layer BC1 is provided under the glass substrate GS, and the top coating layer BC3 is provided above the cover glass CG. The first base coating layer BC1 and the top coating layer BC3 are filled in the first pattern P1 and the third pattern P3. Through this configuration, when the second folding area FA2 is operated in a folding manner outside the second folding area FA2, the folding stress applied to the second folding area FA2 is reduced and the durability of the display device can be improved.

[0154] Figure 12The foldable display device 1000 shown can realize the foldable display device 1000 including a glass substrate GS with improved foldability and durability by forming different patterns in the first folding area FA1 and the second folding area FA2 having different folding directions and curvature radii to simultaneously realize inward folding and outward folding modes.

[0155] In the following, reference will be made to 13A to 13B Shear stress according to positions of a foldable display device according to an exemplary embodiment of the present disclosure and a foldable display device according to a comparative embodiment is described.

[0156] Figure 13A FIG. 1 is a diagram showing simulation results of a folding test of the foldable display device according to Embodiment 1. FIG. Figure 13B 1 is a diagram showing the results of a folding test simulation of the foldable display device according to Comparative Embodiment 1.

[0157] In embodiment 1, a Figure 4 A foldable display device having the structure shown. In Embodiment 1, a bottom glass substrate GS having a thickness of 100 μm and a modulus of 73.3 GPa, a top cover glass CG having a thickness of 140 μm and a modulus of 73.3 GPa, an overcoat layer 190 having a thickness of 3 μm and a modulus of 6.3 GPa, and a first basecoat layer BC1 having a modulus of 300 MPa are formed. Furthermore, first patterns P1 on the bottom glass substrate GS and second patterns P2 on the overcoat layer 190 are formed with a width and spacing of 10 μm. In Comparative Embodiment 1, the same structure as in Embodiment 1 is formed, except that the second pattern P2 is not formed on the overcoat layer 190.

[0158] exist Figure 13A and Figure 13B , shows simulation results obtained by calculating the strain stress applied to the display device when the folding region of the foldable display device according to Embodiment 1 and Comparative Embodiment 1 was pressed with a tip having a diameter of 2 mm at a load of 0.2 kgf. At this time, all simulations were analyzed using the Abaqus tool.

[0159] right Figure 13A and Figure 13B Comparison showed that strain stress was significantly high locally in Comparative Example 1. Furthermore, when the first pattern of the glass substrate and the second pattern of the overcoat layer were alternately arranged as in Example 1, the average strain stress was reduced by 7% or more compared to the comparative example.

[0160] Exemplary embodiments of the present disclosure may also be described as follows:

[0161] According to one aspect of the present disclosure, a foldable display device is provided. The foldable display device includes a folding area and non-folding areas on both sides of the folding area, the folding area including folding shoulder areas located on both sides so as to be adjacent to the non-folding areas and a folding central area located inside the folding shoulder areas on both sides. The foldable display device includes: a glass substrate including a first pattern arranged to correspond to the folding area; a first primer layer arranged on the bottom surface of the glass substrate and filled in the first pattern; a light-emitting diode on the glass substrate; an encapsulation layer on the light-emitting diode; a plurality of color filters and a black matrix on the encapsulation layer; and a cover glass on the plurality of color filters. Any one of the organic material layers located between the plurality of color filters and the cover glass includes a second pattern arranged to correspond to the folding area.

[0162] The first pattern may be formed of grooves formed from a bottom surface of the glass substrate toward a top surface of the glass substrate.

[0163] The first pattern may be formed by a plurality of grooves, and the plurality of grooves located in the shoulder region of the fold may have a smaller thickness or width or spacing than the plurality of grooves located in the central region of the fold.

[0164] The folding region may be folded inwardly so that a display surface of the foldable display device faces inwardly, the second pattern may be formed by a plurality of openings passing through any one of the organic material layers, and the plurality of openings may be provided in the folding shoulder region.

[0165] The plurality of grooves in the folded shoulder region of the glass substrate may be arranged to alternate with the plurality of openings.

[0166] The organic material layer may include an overcoat layer on the plurality of color filters; and an adhesive layer on the overcoat layer. The second pattern may be formed on the overcoat layer.

[0167] The organic material layer may include an outer coating layer disposed on the plurality of color filters, the second pattern may be formed by grooves formed from a top surface of the outer coating layer toward a bottom surface of the outer coating layer, the first pattern may have a step shape that deepens toward a folded central area, and the second pattern may have a step shape that deepens toward a non-folded area.

[0168] The cover glass may include a third pattern disposed to correspond to the folding area, and the third pattern may be formed of a plurality of grooves formed from a bottom surface toward a top surface of the cover glass.

[0169] The foldable display device may further include a second primer layer disposed on the bottom surface of the cover glass and filled in the third pattern. The third pattern may have the same shape as the first pattern.

[0170] The organic material layer may include an overcoat layer on the plurality of color filters; and an adhesive layer on the overcoat layer. The third pattern may include a plurality of recesses formed from the bottom surface toward the top surface of the cover glass and a protrusion protruding toward the adhesive layer. The second pattern may be formed on the adhesive layer via the protrusions. The adhesive layer may fill the third pattern.

[0171] The foldable display device may further include a top coating on the cover glass. The folding region may fold outward so that the display surface of the foldable display device faces outward. The cover glass may include a third pattern arranged to correspond to the folding region. The third pattern may be formed by a plurality of grooves formed from the top surface to the bottom surface of the cover glass. The top coating may fill the third pattern.

[0172] The organic material layer may include an overcoat layer on the plurality of color filters; and an adhesive layer on the overcoat layer. The second pattern may be formed by a plurality of openings passing through the overcoat layer so as to correspond to the folded central area.

[0173] The plurality of openings of the overcoat layer can be positioned to overlap the plurality of grooves of the cover glass.

[0174] The organic material layer may include an overcoat layer on the plurality of color filters; and an adhesive layer on the overcoat layer. The second pattern may be formed by a plurality of openings passing through the adhesive layer so as to correspond to the folded central area.

[0175] Each of the plurality of grooves of the cover glass located in the folded central region may be connected to each of the plurality of openings of the adhesive layer.

[0176] The foldable display device may further include an etch stop layer disposed between the overcoat layer and the adhesive layer.

[0177] The folding area may include a first folding area and a second folding area, the first folding area folds inward so that the display surface of the foldable display device faces inward, and the second folding area folds outward so that the display surface of the foldable display device faces outward. The first pattern may include a 1-1 pattern arranged to correspond to the first folding area and a 1-2 pattern arranged to correspond to the second folding area. The second pattern may include a 2-1 pattern arranged to correspond to the first folding area and a 2-2 pattern arranged to correspond to the second folding area. The 1-1 pattern located in the first folding area may have the same shape as the 1-2 pattern in the second folding area, and the 2-1 pattern located in the first folding area may have a different shape from the 2-2 pattern in the second folding area.

[0178] The organic material layer may include an overcoat layer on the plurality of color filters; and an adhesive layer on the overcoat layer. The 2-1st pattern may be formed by a plurality of 2-1st openings passing through the overcoat layer so as to correspond to the fold shoulder region, and the 2-2nd pattern may be formed by a plurality of 2-2nd openings passing through the overcoat layer so as to correspond to the fold center region.

[0179] The cover glass may include a 3-1st pattern arranged to correspond to the first folding area and a 3-2nd pattern arranged to correspond to the second folding area, and the 3-1st pattern located in the first folding area may have a different shape from the 3-2nd pattern located in the second folding area.

[0180] The 3-1st pattern may be formed by a plurality of 3-1st grooves formed from the bottom surface of the cover glass toward the top surface of the cover glass, and the 3-2nd pattern may be formed by a plurality of 3-2nd grooves formed from the top surface of the cover glass toward the bottom surface of the cover glass.

[0181] Although the exemplary embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited thereto, and the present disclosure can be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, the exemplary embodiments of the present disclosure are provided for illustrative purposes only and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above exemplary embodiments are illustrative in all aspects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the appended claims, and all technical concepts within their equivalent scope should be interpreted as falling within the scope of the present disclosure.

Claims

1. A foldable display device comprising a folding region and non-folding regions located on either side of the folding region, the folding region comprising folding shoulder regions located on either side so as to be adjacent to the non-folding region, and a folding central region located inside the folding shoulder regions on either side, the foldable display device comprising: a glass substrate comprising a first pattern arranged to correspond to the folding area; a first primer layer disposed on the bottom surface of the glass substrate and filling the first pattern; a light emitting diode on the glass substrate; an encapsulation layer on the light-emitting diode; a plurality of color filters and a black matrix on the encapsulation layer; as well as a cover glass on the plurality of color filters, Any one of the organic material layers located between the plurality of color filters and the cover glass includes a second pattern arranged to correspond to the folding area.

2. The foldable display device according to claim 1, wherein: The first pattern is formed of grooves formed from a bottom surface of the glass substrate toward a top surface of the glass substrate.

3. The foldable display device according to claim 2, wherein: The first pattern is formed by a plurality of grooves, and the plurality of grooves located in the fold shoulder region have a smaller thickness or width or spacing than the plurality of grooves located in the fold central region.

4. The foldable display device according to claim 2, wherein: The folding region is folded inwardly so that a display surface of the foldable display device faces inwardly, the second pattern is formed by a plurality of openings passing through any one of the organic material layers, and the plurality of openings are provided in the folding shoulder region.

5. The foldable display device according to claim 4, wherein: The plurality of grooves of the glass substrate in the folded shoulder region are arranged to alternate with the plurality of openings.

6. The foldable display device according to claim 5, wherein: The organic material layer includes: an overcoat layer on the plurality of color filters; and an adhesive layer on the outer coating, and The second pattern is formed on the outer coating layer.

7. The foldable display device according to claim 2, wherein: The organic material layer includes an overcoat layer disposed on the plurality of color filters, The second pattern is formed by grooves formed from the top surface of the outer coating layer toward the bottom surface of the outer coating layer, The first pattern has a stepped shape that deepens toward the folded central area, and The second pattern has a stepped shape that deepens toward the unfolded region.

8. The foldable display device according to claim 1, wherein: The cover glass includes a third pattern arranged to correspond to the folding area, and The third pattern is formed by a plurality of grooves formed from a bottom surface toward a top surface of the cover glass.

9. The foldable display device according to claim 8, further comprising: a second primer layer disposed on the bottom surface of the cover glass and filled in the third pattern; The third pattern has the same shape as the first pattern.

10. The foldable display device according to claim 9, wherein: The organic material layer includes: an overcoat layer on the plurality of color filters; and an adhesive layer on the outer coating, and The third pattern includes a plurality of concave portions formed from the bottom surface toward the top surface of the cover glass and convex portions protruding toward the adhesive layer. The second pattern is formed on the adhesive layer by the protrusion, and The adhesive layer is filled in the third pattern.

11. The foldable display device according to claim 1 , further comprising: A top coating on the cover glass, wherein the folding area is folded outward so that the display surface of the foldable display device faces outward, The cover glass includes a third pattern arranged to correspond to the folding area, The third pattern is formed by a plurality of grooves formed from the top surface to the bottom surface of the cover glass, and The top coating layer is filled in the third pattern.

12. The foldable display device according to claim 11, wherein: The organic material layer includes: an overcoat layer on the plurality of color filters; and an adhesive layer on the outer coating, and The second pattern is formed by a plurality of openings passing through the outer coating layer so as to correspond to the folded central area.

13. The foldable display device according to claim 12, wherein: The plurality of openings of the overcoat layer are positioned to overlap the plurality of grooves of the cover glass.

14. The foldable display device according to claim 11, wherein: The organic material layer includes: an overcoat layer on the plurality of color filters; and an adhesive layer on the outer coating, and The second pattern is formed by a plurality of openings passing through the adhesive layer so as to correspond to the folded central area.

15. The foldable display device according to claim 14, wherein: Each of the plurality of grooves of the cover glass located in the folded central region is connected to each of the plurality of openings of the adhesive layer.

16. The foldable display device according to claim 15, further comprising: An etch stop layer is disposed between the overcoat layer and the adhesion layer.

17. The foldable display device according to claim 1, wherein: The folding area includes a first folding area and a second folding area, the first folding area folds inward so that the display surface of the foldable display device faces inward, and the second folding area folds outward so that the display surface of the foldable display device faces outward, The first pattern includes a 1-1 pattern corresponding to the first folding area and a 1-2 pattern corresponding to the second folding area. The second pattern includes a 2-1 pattern corresponding to the first folding area and a 2-2 pattern corresponding to the second folding area. The 1-1 pattern in the first folding region has the same shape as the 1-2 pattern in the second folding region, and The 2-1 pattern located in the first folding region has a shape different from that of the 2-2 pattern located in the second folding region.

18. The foldable display device according to claim 17, wherein: The organic material layer includes: an overcoat layer on the plurality of color filters; and an adhesive layer on the outer coating, and The 2-1st pattern is formed by a plurality of 2-1st openings passing through the outer coating layer so as to correspond to the folded shoulder areas, and The 2-2 pattern is formed by a plurality of 2-2 openings penetrating the outer coating layer so as to correspond to the folded central area.

19. The foldable display device according to claim 17, wherein: The cover glass includes a 3-1 pattern arranged to correspond to the first folding area and a 3-2 pattern arranged to correspond to the second folding area, and The 3-1st pattern located in the first folding region has a shape different from that of the 3-2nd pattern located in the second folding region.

20. The foldable display device according to claim 19, wherein: The 3-1st pattern is formed by a plurality of 3-1st grooves formed from the bottom surface of the cover glass toward the top surface of the cover glass, and The 3-2nd pattern is formed by a plurality of 3-2nd grooves formed from the top surface of the cover glass toward the bottom surface of the cover glass.

21. A foldable display device comprising a folding region and non-folding regions located on both sides of the folding region, the folding region comprising folding shoulder regions located on both sides so as to be adjacent to the non-folding region and a folding central region located inside the folding shoulder regions on both sides, the foldable display device comprising: a glass substrate comprising a first pattern arranged to correspond to the folding area; a first primer layer disposed on the bottom surface of the glass substrate and filling the first pattern; a display panel on the glass substrate, the display panel comprising a light emitting diode, a plurality of color filters and a black matrix; as well as a cover glass on the plurality of color filters, One of the organic material layers located between the plurality of color filters and the cover glass includes a pattern corresponding to the folded central area.

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