Foldable display devices

Abstract

The present invention discloses a foldable display device, which includes: a display panel; a first plate below the display panel; and a support structure, which is below the first plate and has a foldable area and two non-foldable areas on two opposite sides of the foldable area. The support structure includes: a first support plate, which has a plurality of opening patterns defined in the foldable area; a second support plate, which is above the first support plate and includes a material different from that of the first support plate; and a first adhesive layer, which is between the first support plate and the second support plate. The first adhesive layer has: a first portion in each of the non-foldable areas of the support structure; and a second portion in the foldable area of ​​the support structure. The second portion has a higher degree of curing than each of the first portions.

Description

Technical Field

[0001] The present disclosure relates to a foldable display device, and more particularly, to a foldable display device that can reduce display quality defects caused by an opening pattern of a support structure. Background Art

[0002] As society enters the fully mature information age, various display devices that process and display large amounts of information have been developed. There are various types of display devices that display images, such as liquid crystal display devices (LCDs), organic light emitting display devices (OLEDs), and electrophoretic display devices (EPDs).

[0003] Users who watch broadcasts, videos, or play video games on display devices tend to prefer portable display devices with large screens. However, when the screen of a portable display device is enlarged, its portability deteriorates. Therefore, there is a limit to enlarging the screen. Research on foldable display devices that can fold and unfold display panels that can achieve both large screens and portability has been actively conducted. Summary of the invention

[0004] In a foldable display device, the flexible substrate of the display panel is very thin. Therefore, a backplane that can support the display panel can be attached to the bottom surface of the display panel. For example, the backplane can be made of a polymer film and can be attached to the display panel via an adhesive layer. When the folding operation and the unfolding operation of the foldable display device are repeated, plastic deformation occurs in the backplane made of the polymer film in the foldable region. This leads to the problem that the folding characteristics of the foldable display device may be degraded. In order to compensate for this degradation, a high-rigidity support structure is attached to the bottom surface of the backplane. The support structure includes a high-rigidity metal plate with a thin thickness. The high-rigidity metal plate has a high restoring force. However, the elastic deformation zone of the high-rigidity metal plate is narrow. Therefore, an opening pattern is formed in the foldable region to expand the elastic deformation zone of the metal plate. At this point, there is a problem that the step caused by the opening pattern formed in the support structure is transferred to the display surface of the display device, resulting in poor display quality.

[0005] Accordingly, embodiments of the present disclosure are directed to a foldable display device that substantially obviates one or more problems due to limitations and disadvantages of the related art.

[0006] An aspect of the present disclosure is to provide a foldable display device having excellent folding characteristics and which can reduce display quality defects due to an opening pattern of a support structure.

[0007] Furthermore, an aspect of the present disclosure is to provide a foldable display device that can improve puncture strength.

[0008] Additional features and aspects will be set forth in the following description and, to some extent, will be apparent from the description or may be learned by practice of the inventive concepts provided herein. Other features and aspects of the inventive concepts may be realized and obtained by the structures particularly pointed out in the written description or inferable therefrom, as well as the claims and drawings thereof.

[0009] According to an embodiment of the present disclosure, a foldable display device includes: a display panel; a first plate below the display panel; and a supporting structure, which is below the first plate and has a foldable area and two non-foldable areas respectively on two opposite sides of the foldable area, wherein the supporting structure includes: a first supporting plate, which has a plurality of opening patterns defined in the foldable area of ​​the supporting structure; a second supporting plate, which is above the first supporting plate and includes a material different from the material of the first supporting plate; and a first adhesive layer, which is between the first supporting plate and the second supporting plate, wherein the first adhesive layer of the supporting structure has: a first portion in each of the two non-foldable areas of the supporting structure respectively; and a second portion in the foldable area of ​​the supporting structure, wherein the second portion has a degree of cure higher than that of each of the first portions.

[0010] In other aspects, a foldable display device includes: a display panel; and a board assembly below the display panel, wherein the board assembly includes an upper board, a lower board below the upper board, and a first adhesive layer between the upper board and the lower board, wherein the lower board has a plurality of opening patterns defined therein, wherein the first adhesive layer covers the plurality of opening patterns and has different portions with different moduli.

[0011] In other aspects, a foldable display device includes: a display panel; a first plate below the display panel; and a supporting structure, which is below the first plate and has a foldable area and two non-foldable areas on two opposite sides of the foldable area, respectively, wherein the supporting structure includes: a first supporting plate, the first supporting plate having a plurality of opening patterns defined in the foldable area of ​​the supporting structure; a second supporting plate, the second supporting plate being above the first supporting plate and including a material different from that of the first supporting plate; and a first adhesive layer, the first adhesive layer being a single curing type adhesive layer between the first supporting plate and the second supporting plate, wherein the first adhesive layer has: a first part, the first part being respectively in each of the two non-foldable areas of the supporting structure; and a second part, the second part being in the foldable area of ​​the supporting structure, wherein the second part has a higher degree of cure than each of the first parts, wherein the first part and the second part of the first adhesive layer are first cured under light, and then only the second part of the first adhesive layer is further cured under light.

[0012] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the inventive concepts as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this disclosure, illustrate embodiments of the disclosure and together with the description serve to explain various principles.

[0014] Figure 1 is a perspective view illustrating a display device according to an example embodiment of the present disclosure.

[0015] Figure 2 is a cross-sectional view showing a display device according to an example embodiment of the present disclosure.

[0016] Figure 3 is a plan view showing a first support plate included in a support structure according to an example embodiment of the present disclosure.

[0017] Figure 4 is a plan view showing an adhesive layer included in a support structure and disposed on a first support plate according to an example embodiment of the present disclosure.

[0018] Figure 5 is a cross-sectional view showing a display device according to an example embodiment of the present disclosure.

[0019] Figures 6 to 9 They are cross-sectional views respectively showing a support structure according to an example embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] Reference will now be made in detail to the embodiments of the present disclosure, examples of which may be illustrated in the accompanying drawings. In the following description, a detailed description of the known functions or configurations associated with this document will be omitted. The described processing steps and / or the progress of the operations are examples. Except for the steps and / or operations that must occur in a particular order, the order of the steps and / or operations is not limited to the order set forth herein and may be changed as known in the art or as apparent to those skilled in the art. The names of the corresponding elements used in the following description are selected only for the convenience of writing the specification, and therefore may be different from the names of the elements used in the actual product.

[0021] The advantages and features of the present disclosure and methods for implementing the same are explained by referring to the example implementations described below in conjunction with the accompanying drawings. However, the present disclosure can be implemented in various different forms and is not limited to the example implementations described herein. More specifically, these example implementations are provided so that the present disclosure can be sufficiently thorough and complete to help those skilled in the art fully understand the scope of the present disclosure, which is limited only by the scope of the claims.

[0022] The shapes, sizes, ratios, angles and numbers disclosed in the accompanying drawings for describing the embodiments of the present disclosure are exemplary only. Therefore, the present disclosure is not limited to the details described. Unless otherwise specified, similar reference numerals refer to similar elements throughout the text. In the following description, when a detailed description of a related known function or configuration is determined to be unnecessary to obscure the focus of the present disclosure, a detailed description of such known function or configuration may be omitted. In addition, in the following detailed description of the present disclosure, many specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it should be understood that the present disclosure can be practiced without these specific details. In other cases, well-known methods, processes, components and circuits are not described in detail to avoid unnecessary obscurity of various aspects of the present disclosure.

[0023] The terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular components "one" and "one" are intended to also include plural components. In the case of using the terms "comprising", "having", "including" in this specification, other parts can be added, unless more restrictive terms such as "only" are used. Unless otherwise specified, the terms in the singular form may include plural forms. As used herein, the term "and / or" includes any combination and all combinations of one or more items in the associated listed items. Expressions such as "at least one" can modify the entire list of elements when before the list of elements, and may not modify the individual elements of the list. When explaining a numerical value, even if there is no clear description of it, errors or tolerances therein may also occur.

[0024] In addition, it should also be understood that when a first element or layer is referred to as being present "on" a second element or layer, the first element may be directly disposed on the second element, or may be indirectly disposed on the second element, wherein a third element or layer is disposed between the first element or layer and the second element or layer. It should be understood that when an element or layer is referred to as being "connected to" or "coupled to" another element or layer, it may be directly on another element or layer, directly connected to another element or layer, or directly coupled to another element or layer, or one or more intermediate elements or layers may be present. In addition, it should also be understood that when an element or layer is referred to as being "between" two elements or layers, it may be the only element or layer between the two elements or layers, or one or more intermediate elements or layers may also be present.

[0025] In addition, as used herein, when a layer, film, region, plate, etc. may be disposed "on" or "on top of" another layer, film, region, plate, etc., the former may directly contact the latter, or another layer, film, region, plate, etc. may be between the former and the latter. As used herein, when a layer, film, region, plate, etc. is disposed directly "on" or "on top of" another layer, film, region, plate, etc., the former directly contacts the latter, and no further layer, film, region, plate, etc. is disposed between the former and the latter. In addition, as used herein, when a layer, film, region, plate, etc. may be disposed "under" or "below" another layer, film, region, plate, etc., the former may directly contact the latter, or another layer, film, region, plate, etc. may be disposed between the former and the latter. As used herein, when a layer, film, region, plate, etc. is disposed directly "under" or "below" another layer, film, region, plate, etc., the former directly contacts the latter, and no further layer, film, region, plate, etc. is disposed between the former and the latter.

[0026] When describing a temporal relationship, for example a temporal precedence relationship between two events such as "after", "subsequently", "before", etc., other events may occur between the two events unless "directly after", "directly subsequent" or "directly before" is indicated.

[0027] When describing the elements of the present disclosure, terms such as "first", "second", "A", "B", "(a)", and "(b)" may be used. These terms are only used to distinguish one element from another element, and the nature, order, sequence, or number of the corresponding elements should not be limited by the terms. Therefore, without departing from the spirit and scope of the present disclosure, the first element, component, region, layer, or part described below may be referred to as a second element, component, region, layer, or part.

[0028] The features of various embodiments of the present disclosure may be combined with each other in part or in whole, and may be technically associated with each other or operate with each other. The embodiments may be implemented independently of each other, and may be implemented together in an associated relationship.

[0029] When interpreting numerical values, the values ​​are interpreted as including the error range unless explicitly stated otherwise.

[0030] It should be understood that when an element or layer is referred to as being “connected to” or “coupled to” another element or layer, it can be directly on, directly connected to, or directly coupled to the other element or layer, or one or more intervening elements or layers may be present. In addition, it should be understood that when an element or layer is referred to as being “between” two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers may also be present.

[0031] The features of various embodiments of the present disclosure may be combined with each other in part or in whole, and may be technically associated with each other or operate with each other. The embodiments may be implemented independently of each other, and may be implemented together in an associated relationship.

[0032] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the inventive concept belongs. It should also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0033] Hereinafter, a foldable display device according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0034] Figure 1is a perspective view of a foldable display device according to an example embodiment of the present disclosure.

[0035] Reference Figure 1 , the foldable display device 100 may include a display area AA, a non-display area NA, a foldable area FA, and a non-foldable area NFA.

[0036] The display area AA may be an area where an image is displayed. The non-display area NA is located at the periphery of the display area AA and may be an area where an image is not displayed.

[0037] The foldable area FA may include a folding axis Fx and may overlap a portion of the display area AA and a portion of the non-display area NA. For example, the foldable area FA may be an area that can be folded with a predefined curvature when the foldable display device 100 is folded in at least one of an inner folding scheme and an outer folding scheme. An area other than the foldable area FA may be a non-foldable area NFA. The non-foldable area NFA may overlap a portion of the display area AA and a portion of the non-display area NA.

[0038] In addition, the foldable display device 100 may further include a hinge structure for folding the display panel, etc. and a housing for supporting and accommodating the display panel, etc. The foldable area FA and the non-foldable area NFA may be equally applied to components of the foldable display device 100 .

[0039] Figure 2 is a cross-sectional view illustrating a foldable display device according to an example embodiment of the present disclosure. Figure 3 is a plan view showing a first support plate included in a support structure according to an example embodiment of the present disclosure. Figure 4 is a plan view showing an adhesive layer included in a support structure and disposed on a first support plate according to an embodiment of the present disclosure.

[0040] Reference Figure 2 , the foldable display device 100 may include a support structure PS, a first plate 130 , a display panel 140 , a polarizing layer 150 , a light blocking layer 180 , and a cover window 190 .

[0041] The display panel 140 may display an image. The display panel 140 may be flexible and may display an image to a user. For example, the display panel 140 may be implemented as an organic light-emitting display panel. However, the present disclosure is not limited thereto. The display panel 140 may be of various types, for example, a liquid crystal display panel, an electrophoretic display panel, and the like. When the display panel 140 is implemented as an organic light-emitting display panel, the display panel 140 may include: a thin film transistor array formed on a substrate and including thin film transistors (switching thin film transistors and driving thin film transistors) corresponding to sub-pixels; an organic light-emitting layer having organic light-emitting elements corresponding to sub-pixels and connected to driving thin film transistors, respectively; and an encapsulation layer covering the organic light-emitting layer to prevent moisture and oxygen from penetrating into the organic light-emitting layer from the outside. A touch electrode array formed on the encapsulation layer may also be included. In another example, a touch panel including a touch electrode array may be formed on the polarization layer 150.

[0042] The first plate 130 may be disposed below the display panel 140 and may support the display panel 140. The display panel 140 applied to the foldable display device 100 may be very thin and flexible. The first plate 130 enhances the rigidity of the display panel 140, prevents foreign matter from adhering to the bottom surface of the display panel 140 and buffers impacts from the outside. The first plate 130 may be made of, for example, polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN) or metal. However, the present disclosure is not limited thereto. An adhesive layer 135 may be disposed between the first plate 130 and the display panel 140. For example, the first plate 130 may be attached to the bottom surface of the display panel 140 via the adhesive layer 135. The first plate 130 may be a backplane. The present disclosure is not limited to this term.

[0043] The support structure PS may be disposed below the first plate 130 and may support the display panel 140. The support structure PS may facilitate the folding and unfolding of the display panel 140. The support structure PS may dissipate the heat generated from the display panel 140 to the outside. The support structure PS may include a foldable area FA and a non-foldable area NFA on each of two opposite sides of the foldable area FA. The support structure PS may include at least one support plate. The support structure PS may include a first support plate 110 and a second support plate 120. The support structure PS may also include an adhesive layer 115 disposed between the first support plate 110 and the second support plate 120. The support structure PS may also include an adhesive layer 125 and may be attached to the bottom surface of the first plate 130 via the adhesive layer 125. For example, the adhesive layer 125 may be disposed between the first plate 130 and the support structure PS. For example, the support structure PS may be a plate assembly.

[0044] The first support plate 110 may have a plurality of opening patterns 110h defined in the foldable area FA thereof. Figure 3 , a plurality of opening patterns 110h may extend in a direction parallel to the folding axis (hereinafter referred to as the folding axis direction) and may be arranged in a discontinuous form. The length of each of the plurality of opening patterns 110h may be less than the width of the first support plate 110 in the folding axis direction. The shapes and arrangements of the plurality of opening patterns 110h are not limited to the shapes and arrangements shown. The spacing between the opening patterns 110h adjacent to each other in a direction perpendicular to the folding axis Fx may be uniform. However, the present disclosure is not limited thereto. The spacing between the opening patterns 110h adjacent to each other in a direction perpendicular to the folding axis Fx may increase as the pattern is positioned away from the folding axis Fx. The first spacing between the opening patterns 110h adjacent to each other in a direction perpendicular to the folding axis Fx in the central portion adjacent to the folding axis Fx may be less than the second spacing between the opening patterns 110h adjacent to each other in a direction perpendicular to the folding axis Fx in the edge portion on either side of the central portion.

[0045] The second support plate 120 may be disposed on the first support plate 110. The second support plate 120 may be made of a material different from that of the first support plate 110. For example, the first support plate 110 may be made of a metal having excellent thermal conductivity. For example, the first support plate 110 may be made of stainless steel. The second support plate 120 may be made of a polymer that blocks ultraviolet rays. For example, the second support plate 120 may be made of black polyethylene terephthalate (PET). The first support plate 110 may be used as a lower plate, and the second support plate 120 may be used as an upper plate.

[0046] The adhesive layer 115 may be configured to have different moduli in its non-foldable area NFA and foldable area FA. For example, the adhesive layer 115 may have a first portion 115n disposed in the non-foldable area NFA and a second portion 115f disposed in the foldable area FA. The second portion 115f may have a larger modulus than each of the first portions 115n. In this regard, the modulus may be a storage modulus or a Young's modulus. The second portion 115f may have a modulus of about 10 6 Pa to 10 7 Pa, and the first portion 115n may have a modulus of about 10 4 Pa to 10 5 The modulus of Pa.

[0047] Reference Figure 4, the second portion 115f of the adhesive layer 115 may cover the plurality of opening patterns 110h of the first support plate 110. For example, the second portion 115f of the adhesive layer 115 may cover all of the plurality of opening patterns 110h of the first support plate 110. The second portion 115f may penetrate the foldable area FA and be provided as a single body. The adhesive layer 115 may be transparent or include a black pigment.

[0048] The adhesive layer 115 may be configured to have different degrees of curing in its non-foldable area NFA and foldable area FA. For example, the adhesive layer 115 may have a first portion 115n disposed in the non-foldable area NFA and a second portion 115f disposed in the foldable area FA and having a higher degree of curing than the first portion 115n.

[0049] At least two curing processes may be performed so that the adhesive layer 115 has different degrees of curing in the non-foldable area NFA and the foldable area FA. The adhesive layer 115 may be a single curing type adhesive layer, such as a light curing type adhesive layer, such as an ultraviolet curing type adhesive layer. First, each of the first parts 115n of the adhesive layer 115 may be cured under light (e.g., UV), and then the second part 115f of the adhesive layer 115 may be further cured under light (e.g., UV). To this end, the entire adhesive layer 115 including the first part 115n and the second part 115f may be first cured under light, and then only the second part 115f may be further cured under light using a light blocking mask covering the first part 115n. In this way, an adhesive layer 115 having a second part 115f having a higher degree of curing than each of the first parts 115n may be manufactured. When the composition for forming the adhesive layer 115 includes one type of photoinitiator, the method may include: irradiating ultraviolet light to the first portion 115n for a first duration, and irradiating ultraviolet light to the second portion 115f for a second duration longer than the first duration. In this way, the adhesive layer 115 having the second portion 115f having a higher degree of curing than each of the first portions 115n can be manufactured. In contrast, the composition for forming the adhesive layer 115 includes two different types of photoinitiators having different absorption wavelengths, for example, a short-wavelength photoinitiator that absorbs ultraviolet light of a short wavelength of 250nm or less and a long-wavelength photoinitiator that absorbs ultraviolet light of a long wavelength of 300nm or more. In this case, the method may include: irradiating only short-wavelength ultraviolet light or long-wavelength ultraviolet light to the first portion 115n, and irradiating both short-wavelength ultraviolet light and long-wavelength ultraviolet light to the second portion 115f. In this way, the adhesive layer 115 having the second portion 115f having a higher degree of curing than each of the first portions 115n can be manufactured. The curing degree of the second portion 115 f may be approximately 76% to 90%, and the curing degree of each of the first portions 115 n may be approximately 68% to 75%.

[0050] In another exemplary embodiment of the present disclosure, the adhesive layer 115 may be a dual-curing adhesive layer. The adhesive layer 115 may be cured with two curing schemes selected from heat curing, light curing or moisture curing. The first portion 115n and the second portion 115f of the adhesive layer 115 may be first cured with a first curing scheme as a curing scheme among heat curing, light curing and moisture curing, and then, the second portion 115f may be second cured with a second curing scheme different from the first curing scheme and selected from heat curing, light curing and moisture curing. For example, the first portion 115n and the second portion 115f of the adhesive layer 115 may be first cured with a heat curing scheme, and then the second portion 115f may be second cured with a light curing scheme (e.g., with an ultraviolet curing scheme). In this regard, the entire adhesive layer 115 including the first portion 115n and the second portion 115f may be first cured with a heat curing scheme, and then, the second portion 115f may be second cured with a light curing scheme (e.g., with an ultraviolet curing scheme) using a light-blocking mask covering the first portion. Therefore, the adhesive layer 115 having the second portion 115f having a higher degree of curing than each of the first portions 115n may be manufactured.

[0051] In an embodiment of the present disclosure, since the second support plate 120 is made of a polymer that blocks ultraviolet rays, a second photocuring to form the second portion 115f of the layer 115 can be performed without changing the properties of the adhesive layer 125 disposed on the top surface of the second support plate 120 during the second photocuring.

[0052] When the second support plate 120 is made of stainless steel (SUS) or polyimide (PI), the puncture strength of the foldable display device is low, for example, about 4.0 to 4.8 kgF. Unlike the flat panel display device of the prior art, the foldable display device may have a folding characteristic, and therefore, the thickness of the cover window of the foldable display device is much smaller than the thickness of the cover window of the flat panel display device of the prior art. Therefore, when the puncture strength of the foldable display device is as low as the above range, even due to a small external impact, bright spots may appear on the display panel, cracks may appear in the cover window, the adhesive layer may be squeezed, etc. In addition, when the second support plate 120 includes polyimide (PI), the steps caused by the multiple opening patterns 110h of the first support plate 110 may be transferred to the display surface of the foldable display device, which leads to problems with display quality that are discerned by the user.

[0053] In a foldable display device according to an embodiment of the present disclosure, the second support plate 120 of the support structure PS may include a material having excellent toughness. Therefore, this can improve the rigidity characteristics of the foldable display device. In a foldable display device according to an embodiment of the present disclosure, the second support plate 120 of the support structure PS may include polyethylene terephthalate (PET), which has better toughness than stainless steel and polyimide (PI). Therefore, the puncture strength can be improved to about 5.4kgF. The toughness of a material refers to the amount of energy absorbed by the material when the material undergoes plastic deformation before breaking. The total area on the stress-strain curve represents the toughness value. The high toughness of the material enables a good ability to absorb energy from external impacts.

[0054] In the prior art, in terms of heat resistance, colorless polyimide with a high glass transition temperature Tg is applied to the cover window. Accordingly, polyimide is used in the support structure. Therefore, a neutral plane can be formed in the organic light-emitting element region of the display panel or in its thin film transistor array region. However, since the foldable display device must have a folding characteristic, the thickness of the cover window must be reduced. With the increase in the number of products using a touch fan, the demand for a foldable display device with high rigidity to withstand external impacts has also increased.

[0055] In an exemplary embodiment of the present disclosure, a material having excellent toughness characteristics (such as polyethylene terephthalate) may be used for the support structure. Therefore, the puncture strength can be improved, thereby preventing bright spots from appearing on the display panel due to external impact, preventing defects such as cracks in the cover window, and preventing the adhesive layer from being squeezed.

[0056] In the foldable display device according to the example embodiment of the present disclosure, the support structure PS may include an adhesive layer 115 disposed between the first support plate 110 and the second support plate 120 of the support structure PS, wherein the adhesive layer 115 has a second portion 115f that covers the plurality of opening patterns 110h formed in the foldable region of the first support plate 110 and has a modulus greater than that of each of the first portions 115n or has a higher degree of curing than that of each of the first portions 115n. Therefore, the foldable display device may have excellent folding characteristics, and display quality defects of the foldable display device due to steps caused by the opening patterns of the support structure may be suppressed.

[0057] The polarizing layer 150 may be configured to ensure visibility of the display panel 140. For example, the polarizing layer 150 may include a polarizer and a phase retardation film disposed on one surface of the polarizer. The adhesive layer 145 may be disposed between the polarizing layer 150 and the display panel 140. For example, the polarizing layer 150 may be attached to the top surface of the display panel 140 via the adhesive layer 145. The display panel 140 may include various metal materials for thin film transistors, wiring, electrodes, and light-emitting element layers. External light incident on the display panel 140 may be reflected from the metal material as described above, and therefore, the visibility of the foldable display device 100 may be degraded due to the reflection of external light. Therefore, the polarizing layer 150 including the phase retardation film selectively transmits light therethrough, so that the reflection of external light incident on the display panel 140 can be reduced. Therefore, the outdoor visibility of the foldable display device 100 can be improved.

[0058] The cover window 190 may be disposed on the polarizing layer 150. The cover window 190 may include a polymer film. For example, the polymer film may be transparent. The polymer film may include, for example, polyethylene terephthalate (PET), colorless polyimide (PI), or a laminate of polyethylene terephthalate (PET) and colorless polyimide (PI). The cover window 190 may also include a hard coating formed on the transparent polymer film. For example, the hard coating may be a coating. However, the present disclosure is not limited to this term. The hard coating may include a transparent organic-inorganic composite material that can effectively protect the cover window 190 and reduce the degradation of the transmittance. The cover window 190 may protect the polarizing layer 150 and the display panel 140 from external impact, moisture, and heat. An adhesive layer 155 may be disposed between the polarizing layer 150 and the cover window 190. For example, the cover window 190 may be attached to the top surface of the polarizing layer 150 via the adhesive layer 155.

[0059] The light blocking layer 180 may be formed on the edge portion of the cover window 190. The light blocking layer 180 may be covered with an adhesive layer 155 for attaching the cover window 190 to the polarizing layer 150. The light blocking layer 180 may prevent the driver circuit, various wirings, and pads of the non-display area NA of the display panel 140 from being seen by the user. The light blocking layer 180 may be formed in a ring shape. For example, the light blocking layer 180 may be formed by printing black ink. However, the present disclosure is not limited thereto.

[0060] Figure 5 is a cross-sectional view illustrating a foldable display device according to an example embodiment of the present disclosure.

[0061] Reference Figure 5, the foldable display device 100-1 according to an embodiment of the present disclosure may include a protective base 160 and a light blocking layer 180 formed on an edge of a bottom surface of the protective base 160. In an embodiment of the present disclosure, Figure 2 Unlike the foldable display device 100 of the embodiment shown in the figure, the light blocking layer 180 is not formed on the bottom surface of the cover window 190, but the light blocking layer 180 is formed on the bottom surface of the protective base 160. For example, the protective base 160 may include a polymer film made of, for example, polyimide (PI), polyethylene terephthalate (PET), propylene glycol (PPG), and polycarbonate (PC). However, the present disclosure is not limited thereto. The light blocking layer 180 may be formed on the edge portion of the protective base 160. The adhesive layer 155 may be disposed between the protective base 160 and the polarizing layer 150. For example, the protective base 160 may be attached to the top surface of the polarizing layer 150 via the adhesive layer 155. The light blocking layer 180 may be covered with an adhesive layer 155 for attaching the protective base 160 to the polarizing layer 150. The adhesive layer 165 may be disposed between the cover window 190 and the protective base 160. For example, the cover window 190 may be attached to the top surface of the protection base 160 via the adhesive layer 165 .

[0062] Other configurations of the foldable display device 100-1 and their effects may be the same as Figure 2 Other configurations of the foldable display device of the exemplary embodiment and their effects are the same or similar.

[0063] Figures 6 to 9 They are cross-sectional views respectively showing a support structure according to an example embodiment of the present disclosure.

[0064] Reference Figure 6 and Figure 7 , the supporting structure PS-1 or PS-2 of the foldable display device may include: a first adhesive layer 115, the first adhesive layer having a first portion 115n disposed in the non-foldable area NFA and a second portion 115f disposed in the foldable area FA and having a higher degree of curing than each of the first portions 115n; a second adhesive layer 114, the second adhesive layer being disposed on one surface of the first adhesive layer 115 and having a uniform degree of curing. The second adhesive layer 114 may have a lower degree of curing than the second portion 115f of the first adhesive layer 115. The first adhesive layer 115 and the second adhesive layer 114 may be transparent or may include a black pigment. Figure 6 In the support structure PS-1 shown, the second adhesive layer 114 can be disposed below the first adhesive layer 115. Figure 7In the illustrated support structure PS-2, the second adhesive layer 114 may be disposed on the top surface of the first adhesive layer 115. The first adhesive layer 115 and the second adhesive layer 114 may be manufactured separately and then bonded to each other.

[0065] In a foldable display device according to an embodiment of the present disclosure, a support structure PS-1 or PS-2 may include an adhesive layer 115 disposed between a first support plate 110 and a second support plate 120 of the support structure PS-1 or PS-2, wherein the layer 115 has a second portion 115f that covers a plurality of opening patterns 110h formed in a foldable region of the first support plate 110 and has a modulus greater than that of each of the first portions 115n or a degree of cure higher than that of each of the first portions 115n. Therefore, the device may have excellent folding characteristics, and display quality defects of the device due to steps caused by the opening pattern of the support structure may be suppressed. In addition, puncture strength may also be improved in the foldable region.

[0066] Reference Figure 8 and Fig. 9 , the supporting structure PS-3 or PS-4 of the foldable display device may include at least two first adhesive layers 115, wherein each of the at least two first adhesive layers 115 has a first portion 115n disposed in the non-foldable area NFA and a second portion 115f disposed in the foldable area FA and having a higher degree of cure than that of each of the first portions 115n. The supporting structure PS-3 or PS-4 of the foldable display device may also include at least two second adhesive layers 114, wherein each of the at least two second adhesive layers 114 is disposed on one surface or opposite surfaces of each of the first adhesive layers 115 and has a uniform degree of cure. Figure 8 In the support structure PS-3 shown in the example of , two first adhesive layers 115 and three second adhesive layers 114 may be alternately stacked on each other, and the second adhesive layer 114 may constitute each of the lowermost layer and the uppermost layer. Fig. 9 In the support structure PS-3 shown in the example of FIG. 1 , three first adhesive layers 115 and two second adhesive layers 114 may be alternately stacked with each other, and the first adhesive layer 115 may constitute each of the lowermost layer and the uppermost layer. The first adhesive layer 115 and the second adhesive layer 114 may be manufactured separately and then bonded to each other.

[0067] In a foldable display device according to an embodiment of the present disclosure, a support structure PS-3 or PS-4 may include at least two first adhesive layers 115 disposed between a first support plate 110 and a second support plate 120 of the support structure PS-3 or PS-4, wherein each first adhesive layer 115 has a second portion 115f, the second portion 115f covering a plurality of opening patterns 110h formed in a foldable region of the first support plate 110 and having a modulus greater than that of each of the first portions 115n or a degree of cure higher than that of each of the first portions 115n. Therefore, the device may have excellent folding characteristics. Display quality defects that occur when a step caused by the opening pattern of the support structure is transferred to the display surface of the foldable display device may also be suppressed. In addition, puncture strength may also be improved in the foldable region.

[0068] A foldable display device according to an example embodiment of the present disclosure may be described as follows.

[0069] According to an embodiment of the present disclosure, a foldable display device includes: a display panel; a first plate below the display panel; and a supporting structure, which is below the first plate and has a foldable area and two non-foldable areas respectively on two opposite sides of the foldable area, wherein the supporting structure includes: a first supporting plate, which has a plurality of opening patterns defined in the foldable area of ​​the supporting structure; a second supporting plate, which is above the first supporting plate and includes a material different from that of the first supporting plate; and a first adhesive layer, which is between the first supporting plate and the second supporting plate, wherein the first adhesive layer of the supporting structure has: a first portion in each of the two non-foldable areas of the supporting structure respectively; and a second portion in the foldable area of ​​the supporting structure, wherein the second portion has a degree of cure higher than that of each of the first portions.

[0070] In some embodiments of the present disclosure, the second portion of the first adhesive layer covers all of the opening patterns of the plurality of opening patterns of the first support plate.

[0071] In some embodiments of the present disclosure, the first support plate comprises a metal and the second support plate comprises a UV blocking polymer.

[0072] In some embodiments of the present disclosure, the second support plate includes polyethylene terephthalate having a black color.

[0073] In some embodiments of the present disclosure, the foldable display device further includes a second adhesive layer disposed on a surface of the first adhesive layer.

[0074] In some embodiments of the present disclosure, the second adhesive layer has a lower degree of cure than the second portion of the first adhesive layer.

[0075] In some embodiments of the present disclosure, the first adhesive layer includes at least two first adhesive layers, and the second adhesive layer includes at least two second adhesive layers, and wherein the at least two first adhesive layers and the at least two second adhesive layers are alternately stacked on each other.

[0076] In some embodiments of the present disclosure, the first adhesive layer includes an adhesive layer cured in two different curing schemes selected from at least one of a thermal curing scheme, a light curing scheme, and a moisture curing scheme.

[0077] In some embodiments of the present disclosure, a first portion and a second portion of a first adhesive layer are first cured according to a first curing scheme selected from a thermal curing scheme, a light curing scheme, and a moisture curing scheme, and then only the second portion is second cured according to a second curing scheme that is different from the first curing scheme and selected from the thermal curing scheme, the light curing scheme, and the moisture curing scheme.

[0078] According to an embodiment of the present disclosure, a foldable display device includes: a display panel; and a board assembly below the display panel, wherein the board assembly includes an upper board, a lower board below the upper board, and a first adhesive layer between the upper board and the lower board, wherein the lower board has a plurality of opening patterns defined in the lower board, wherein the first adhesive layer covers the plurality of opening patterns and has different portions with different moduli.

[0079] In some embodiments of the present disclosure, the upper plate includes a UV blocking polymer and the lower plate includes a metal.

[0080] In some embodiments of the present disclosure, the first adhesive layer includes first portions in the non-foldable region and second portions in the foldable region, respectively, wherein the second portions have a modulus higher than a modulus of each of the first portions.

[0081] In some embodiments of the present disclosure, the foldable display device further includes a second adhesive layer disposed on one surface or the other surface of the first adhesive layer.

[0082] In some embodiments of the present disclosure, the first adhesive layer includes at least two first adhesive layers, and the second adhesive layer includes at least two second adhesive layers, wherein the at least two first adhesive layers and the at least two second adhesive layers are alternately stacked on each other.

[0083] In some embodiments of the present disclosure, all of the different parts of the first adhesive layer are first cured according to a first curing scheme selected from at least one of a thermal curing scheme, a light curing scheme, and a moisture curing scheme, and then only one of the different parts is second cured according to a second curing scheme that is different from the first curing scheme and selected from at least one of the thermal curing scheme, the light curing scheme, and the moisture curing scheme.

[0084] According to an embodiment of the present disclosure, a foldable display device includes: a display panel; a first plate below the display panel; and a supporting structure, which is below the first plate and has a foldable area and two non-foldable areas on two opposite sides of the foldable area, respectively, wherein the supporting structure includes: a first supporting plate, which has a plurality of opening patterns defined in the foldable area of ​​the supporting structure; a second supporting plate, which is above the first supporting plate and includes a material different from that of the first supporting plate; and a first adhesive layer, which is a single curing type adhesive layer between the first supporting plate and the second supporting plate, wherein the first adhesive layer has: a first part, which is respectively in each of the two non-foldable areas of the supporting structure; and a second part, which is in the foldable area of ​​the supporting structure, wherein the second part has a higher degree of curing than each of the first parts, wherein the first part and the second part of the first adhesive layer are first cured under light, and then only the second part of the first adhesive layer is further cured under light.

[0085] In some embodiments of the present disclosure, a first spacing between opening patterns adjacent to each other in a center portion adjacent to a folding axis of a foldable region in a direction perpendicular to the folding axis is smaller than a second spacing between opening patterns adjacent to each other in an edge portion on either side of the center portion in a direction perpendicular to the folding axis.

[0086] It will be apparent to those skilled in the art that various modifications and variations can be made in the foldable display device of the present disclosure without departing from the technical concept or scope of the present disclosure. Therefore, the embodiments of the present disclosure are intended to cover modifications and variations of the disclosure as long as they fall within the scope of the attached claims and their equivalents.

Claims

1. A foldable display device, comprising: Display panel; a first plate below the display panel; as well as a supporting structure under the first plate and having a foldable area and two non-foldable areas on two opposite sides of the foldable area, Wherein, the supporting structure comprises: a first support sheet having a plurality of opening patterns defined in the foldable region of the support structure; a second support plate above the first support plate and comprising a material different from that of the first support plate; and a first adhesive layer, the first adhesive layer being between the first support plate and the second support plate, Wherein, the first adhesive layer of the supporting structure has: a first portion, one portion in each of the two non-foldable regions of the support structure; and A second portion, the second portion being in the foldable region of the support structure, wherein the second portion has a degree of cure that is higher than a degree of cure of each of the first portions.

2. The foldable display device according to claim 1, wherein: The second portion of the first adhesive layer covers all of the opening patterns of the plurality of opening patterns of the first support plate.

3. The foldable display device according to claim 1, wherein: The first support plate comprises metal, and the second support plate comprises an ultraviolet blocking polymer.

4. The foldable display device according to claim 3, wherein: The second support plate includes polyethylene terephthalate having a black color. 5 . The foldable display device of claim 1 , further comprising a second adhesive layer disposed on a surface of the first adhesive layer.

6. The foldable display device according to claim 5, wherein: The second adhesive layer has a degree of curing lower than a degree of curing of a second portion of the first adhesive layer.

7. The foldable display device according to claim 5, wherein: The first adhesive layer includes at least two first adhesive layers, and the second adhesive layer includes at least two second adhesive layers, and The at least two first adhesive layers and the at least two second adhesive layers are stacked alternately with each other.

8. The foldable display device according to claim 1, wherein: The first adhesive layer includes an adhesive layer cured in two different curing schemes selected from at least one of a heat curing scheme, a light curing scheme, and a moisture curing scheme.

9. The foldable display device according to claim 1, wherein: The first portion and the second portion of the first adhesive layer are first cured using a first curing scheme selected from a thermal curing scheme, a light curing scheme, and a moisture curing scheme, and then only the second portion is second cured using a second curing scheme that is different from the first curing scheme and selected from the thermal curing scheme, the light curing scheme, and the moisture curing scheme.

10. A foldable display device, comprising: Display panel; as well as a board assembly below the display panel, wherein the board assembly includes an upper board, a lower board below the upper board, and a first adhesive layer between the upper board and the lower board, wherein the lower plate has a plurality of opening patterns defined in the lower plate, wherein the first adhesive layer covers the plurality of opening patterns and has different portions with different moduli, and The first adhesive layer includes first portions in the non-foldable region and second portions in the foldable region, respectively, wherein the second portions have a modulus higher than a modulus of each of the first portions.

11. The foldable display device according to claim 10, wherein: The upper plate includes a polymer that blocks ultraviolet light, and the lower plate includes metal. 12 . The foldable display device of claim 10 , further comprising a second adhesive layer on a surface of the first adhesive layer.

13. The foldable display device according to claim 12, wherein: The first adhesive layer includes at least two first adhesive layers, and the second adhesive layer includes at least two second adhesive layers, and The at least two first adhesive layers and the at least two second adhesive layers are alternately stacked with each other.

14. The foldable display device according to claim 10, wherein: All of the different parts of the first adhesive layer are first cured with a first curing scheme selected from at least one of a thermal curing scheme, a light curing scheme, and a moisture curing scheme, and then only one of the different parts is second cured with a second curing scheme that is different from the first curing scheme and selected from at least one of the thermal curing scheme, the light curing scheme, and the moisture curing scheme.

15. A foldable display device, comprising: Display panel; a first plate below the display panel; as well as a supporting structure under the first plate and having a foldable area and two non-foldable areas on two opposite sides of the foldable area, Wherein, the supporting structure comprises: a first support sheet having a plurality of opening patterns defined in the foldable region of the support structure; a second support plate above the first support plate and comprising a material different from that of the first support plate; and a first adhesive layer, the first adhesive layer being a single curing adhesive layer between the first support plate and the second support plate, Wherein, the first adhesive layer has: a first portion, one portion in each of the two non-foldable regions of the support structure; and a second portion, the second portion being in the foldable region of the support structure, wherein the second portion has a degree of cure that is higher than a degree of cure of each of the first portions, The first portion and the second portion of the first adhesive layer are first cured under light, and then only the second portion of the first adhesive layer is further cured under light.

16. A foldable display device according to claim 15, wherein a first spacing between opening patterns adjacent to each other in a center portion adjacent to a folding axis of the foldable area in a direction perpendicular to the folding axis is smaller than a second spacing between opening patterns adjacent to each other in an edge portion on either side of the center portion in a direction perpendicular to the folding axis.

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