Hinge Structure and Foldable Display Device Comprising the Same

Abstract

Disclose a hinge structure and a foldable display device. The foldable display device includes: a first set of housings and a second set of housings, which are arranged opposite to each other in a first direction; a hinge assembly, which is disposed between the first set of housings and the second set of housings; and a display panel, which is disposed above the first set of housings, the second set of housings and the hinge assembly. The hinge assembly includes: a middle rod, which extends between the first set of housings and the second set of housings in a second direction perpendicular to the first direction; a first baffle rod, which is disposed between the first set of housings and the middle rod; a second baffle rod, which is disposed between the second set of housings and the middle rod; a fastening member, which fastens the middle rod, the first baffle rod and the second baffle rod; a support member, which is coupled to the fastening member; a first cam and a second cam, which are disposed on both sides of the support member in the first direction; a spring member, which is disposed below the support member; and a first gear arm and a second gear arm.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10 - 2021 - 0194332, filed with the Korean Intellectual Property Office on December 31, 2021, and Korean Patent Application No. 10 - 2022 - 0181996, filed with the Korean Intellectual Property Office on December 22, 2022, the disclosures of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a hinge structure and a foldable display device including the hinge structure, and more particularly, to a bidirectional foldable hinge structure and a foldable display device including the hinge structure. Background Art

[0004] Recently, mobile terminals such as wireless terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), or electronic notebooks are being miniaturized to ensure portability. However, since users want to receive various information such as character information, videos, still images, MP3s, or games through the screen of a portable terminal, users need a large - sized or wide - sized screen for the display unit. However, the miniaturization of the portable terminal results in a reduction in the size of the screen of the display unit, making it difficult to meet both requirements.

[0005] To overcome the above - mentioned limitations, recently, flexible display devices such as bendable display devices or foldable display devices have been developed.

[0006] A flexible display device can be realized by using a plastic material to form a substrate. When the flexible display device is folded, it is convenient to carry, and when the flexible display device is unfolded, a large screen is realized, so that the flexible display device can be applied to various fields, including not only mobile devices such as mobile phones, e - books, or e - newspapers but also televisions or monitors. Summary of the Invention

[0007] The inventors of the present disclosure have invented a structure using a device composed of a hinge in the area where the display panel is folded to realize a foldable display device in a flexible display device. However, the inventors have recognized that the hinge structures of related technologies can only be folded in one direction, and it is difficult to simultaneously achieve in - folding with the display panel on the inside and out - folding with the display panel on the outside.

[0008] The inventors have also recognized that even if a hinge that can simultaneously achieve in - folding and out - folding is applied, it is difficult to simultaneously solve the panel damage caused by in - folding and the display panel damage caused by out - folding due to repeated folding.

[0009] Accordingly, an object of the present disclosure is to provide a hinge structure and a bidirectional foldable display device including the hinge structure, in which both inward folding and outward folding can be performed.

[0010] Another object of the present disclosure is to provide a foldable display device that can solve damage to a display panel caused by pressure applied to the display panel exposed by outward folding.

[0011] Yet another object of the present disclosure is to provide a foldable display device that solves excessive stress applied to a display panel by a small radius of curvature during inward folding and minimizes cracks and creases in the display panel.

[0012] Another object of the present disclosure is to reduce strain in a portion of the display panel where the maximum strain is applied during repeated inward and outward folding operations.

[0013] Yet another object of the present disclosure is to provide a foldable display device having excellent durability even in repeated folding.

[0014] The objects of the present disclosure are not limited to the objects mentioned above, and other objects not mentioned above will be clearly understood by those skilled in the art from the following description.

[0015] According to an aspect of the present disclosure, a foldable display device includes: a first set of housings and a second set of housings disposed opposite each other in a first direction; a hinge assembly disposed between the first set of housings and the second set of housings; and a display panel disposed above the first set of housings, the second set of housings, and the hinge assembly. The hinge assembly includes: a middle rod extending in a second direction perpendicular to the first direction between the first set of housings and the second set of housings; a first flap bar disposed between the first set housing and the middle rod; a second flap bar disposed between the second set housing and the middle rod; a fastening member fastening the middle rod, the first flap bar, and the second flap bar; a support member coupled to the fastening member; first and second cams disposed on both sides of the support member in the first direction and including a fixing unit that interworks with the first flap bar and the second flap bar and a pressing unit protruding from the fixing unit toward the support member; a spring member disposed below the support member; and first and second gear arms fastened to the fixing units of the first and second cams, respectively.

[0016] According to another aspect of the present disclosure, a hinge structure for a foldable display device includes: a middle rod extending in a second direction; a first baffle rod disposed on one side of the middle rod and extending in the second direction; a second baffle rod disposed on the other side of the middle rod and extending in the second direction; a fastening member fastening the middle rod, the first baffle rod, and the second baffle rod; a support member coupled to the fastening member; a first cam and a second cam disposed on both sides of the support member in a first direction perpendicular to the second direction, the first cam including a fixing unit that cooperates with the first baffle rod and a pressing unit protruding from the fixing unit toward the support member, and the second cam including a fixing unit that cooperates with the second baffle rod and a pressing unit protruding from the fixing unit toward the support member; a spring member disposed below the support member; a first gear arm fastened to the fixing unit of the first cam; and a second gear arm fastened to the fixing unit of the second cam.

[0017] Other details of the exemplary embodiments are included in the detailed description and the drawings.

[0018] According to the present disclosure, a bidirectional foldable display device is provided, in which both inward folding and outward folding can be performed.

[0019] According to the present disclosure, a rounded rectangle corner is formed in the folding area during outward folding to suppress damage to the display panel due to the pressure applied to the display panel.

[0020] According to the present disclosure, the display panel is set in an omega (Ω) shape during inward folding so that the radius of curvature of the display panel in the folding area increases to reduce the stress applied to the folded display panel.

[0021] According to the present disclosure, during both outward folding and inward folding, a support member with a variable position is used to support the display panel in the display area to suppress creases and cracks applied to the display panel.

[0022] According to the present disclosure, even if folding is repeatedly performed, damage to the display panel is minimized and the reliability of the display device is improved.

[0023] 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

[0024] The above and other aspects, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description presented in conjunction with the drawings, in which:

[0025] Figure 1is a perspective view of a foldable display device according to an exemplary embodiment of the present disclosure;

[0026] Figure 2 is a plan view of a part of the configuration of a foldable display device according to an exemplary embodiment of the present disclosure;

[0027] Figure 3 is to Figure 2 is an exploded perspective view of a magnified part A of;

[0028] Figure 4A is a perspective view showing a first cam structure of a foldable display device according to an exemplary embodiment of the present disclosure;

[0029] Figure 4B is a perspective view showing a support member and a gear housing of a foldable display device according to an exemplary embodiment of the present disclosure;

[0030] Figure 5A and Figure 5B is a schematic cross-sectional view showing an unfolded state of a foldable display device according to an exemplary embodiment of the present disclosure;

[0031] Figure 6A and Figure 6B is a schematic cross-sectional view showing an outward-folded state of a foldable display device according to an exemplary embodiment of the present disclosure;

[0032] Figure 7A and Figure 7B is a schematic cross-sectional view showing an inward-folded state of a foldable display device according to an exemplary embodiment of the present disclosure; and

[0033] Figure 8A and 8B is a schematic cross-sectional view showing an inward-folded state of a foldable display device according to another exemplary embodiment of the present disclosure. Detailed Description

[0034] Advantages and features of the present disclosure and methods for achieving these advantages and features will become clear by referring to the following exemplary embodiments described in detail 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 content of the present disclosure and the scope of the present disclosure. Therefore, the present disclosure will be defined only by the scope of the appended claims.

[0035] The shapes, dimensions, ratios, angles, numbers, etc. shown in the drawings for describing the exemplary embodiments of the present disclosure are merely examples, and the present disclosure is not limited thereto. Throughout the specification, like reference numerals generally denote like 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 "comprising", "having", and "consisting of" used herein generally intend to allow the addition of other components, unless these terms are used together with the term "only". Any reference to the singular may include the plural unless otherwise expressly stated.

[0036] Even if not expressly stated, components are construed to include a normal error range.

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

[0038] When an element or layer is disposed "on" another element or layer, another layer or another element may be directly disposed on the other element or layer or between them.

[0039] Although terms such as "first", "second", etc. 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, in the technical concept of the present disclosure, the first component mentioned below may be the second component.

[0040] Throughout the specification, like reference numerals generally denote like elements.

[0041] For convenience of description, the dimensions and thicknesses of each component shown in the drawings are shown, and the present disclosure is not limited to the dimensions and thicknesses of the components shown.

[0042] The features of the various embodiments of the present disclosure may be partially or wholly adhered to or combined with each other, and may be interlocked and operated in various ways technically, and the embodiments may be executed independently or in association with each other.

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

[0044] Figure 1 and Figure 2 are views for illustrating a foldable display device according to an exemplary embodiment of the present disclosure. Figure 1 is a perspective view of a foldable display device according to an exemplary embodiment of the present disclosure, and Figure 2It is a plan view that is part of the configuration of a foldable display device according to an exemplary embodiment of the present disclosure.

[0045] Referring Figure 1 and Figure 2 , the foldable display device 100 according to an exemplary embodiment of the present disclosure includes a set of housings 110 and 120, a hinge assembly 200, a display panel 130, and a bezel cover 140.

[0046] In Figure 1 and Figure 2 , although the components of the foldable display device 100 are briefly shown for ease of description, in fact, it may also include various components for driving the foldable display device 100.

[0047] 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 fully folded or unfolded according to the user's intention. The foldable display device can be folded inward (inward folding) so that the display panel is positioned inside, can be folded outward (outward folding) so that the display panel is positioned outside, and can be unfolded in either direction. The foldable display device 100 according to an exemplary embodiment of the present disclosure is a bi-directional foldable display device that can freely achieve inward folding and outward folding according to the user's intention.

[0048] The set of housings 110 and 120 are outer covers of a set for supporting or accommodating various components of the foldable display device 100 including the display panel 130. The set of housings 110 and 120 may be composed of a first set of housings 110 on the left and a second set of housings 120 on the right, but is not limited thereto.

[0049] The first set of housings 110 and the second set of housings 120 may be spaced apart from each other and the hinge assembly 200 is located between them. The first set of housings 110 and the second set of housings 120 may be disposed opposite to each other, and the hinge assembly 200 is placed between the first set of housings 110 and the second set of housings 120 in the width direction (X-axis direction or first direction). In addition, the first set of housings 110 and the second set of housings 120 may be disposed in one area and another area where the foldable display device 100 according to an exemplary embodiment of the present disclosure is folded and unfolded. That is, by an external force applied by the user to perform the folding and unfolding movement, the foldable display device 100 according to an exemplary embodiment of the present disclosure is folded or unfolded with respect to any area between the first set of housings 110 and the second set of housings 120.

[0050] Referring Figure 2, Each of the first and second sets of housings 110 and 120 includes a support member, a frame, and a fastening unit. Specifically, the first set of housing 110 includes a first support member 112, a first frame 114, and a first fastening unit 116, and the second set of housing 120 includes a second support member 122, a second frame 124, and a second fastening unit 126.

[0051] The first support member 112 and the second support member 122 may be basic members for supporting various components of the foldable display device 100 including the display panel 130. The first support member 112 and the second support member 122 are spaced apart from each other, and the middle bar 210, the first baffle bar 220a, and the second baffle bar 220b are located therebetween.

[0052] The first frame 114 and the second frame 124 are embedded frames of the set, configured to surround and accommodate various components of the foldable display device 100. The first frame 114 and the second frame 124 respectively surround the edges of the first support member 112 and the second support member 122. Specifically, the first frame 114 surrounds three edges of the first support member 112 except for the edge facing the hinge assembly 200. In addition, the second frame 124 surrounds three edges of the second support member 122 except for the edge facing the hinge assembly 200.

[0053] The support member and the frame are separately provided for assembly or have a single structure to continuously connect the support member and the frame. Although in Figure 2 it is shown that the first support member 112 and the first frame 114 are configured as a continuous single structure, and the second support member 122 and the second frame 124 are configured as a continuous single structure, this is not limiting.

[0054] The first fastening unit 116 and the second fastening unit 126 coupled to the hinge assembly 200 are formed in the first frame 114 and the second frame 124. The first fastening unit 116 is formed on the upper and lower edges of the first frame 114 adjacent to the first baffle bar 220a, and the second fastening unit 126 is formed on the upper and lower edges of the second frame 124 adjacent to the second baffle bar 220b. The first fastening unit 116 and the second fastening unit 126 are fastened to the first gear arm 290a and the second gear arm 290b of the hinge assembly 200, which will be described below. The first fastening unit 116 and the second fastening unit 126 may be arranged to face each other during folding.

[0055] The hinge assembly 200 is connected to the first set of housing 110 and the second set of housing 120 to enable the folding and unfolding movement of the foldable display device 100. The hinge assembly 200 includes a middle bar 210 and baffle bars 220a and 220b. The specific structure and function of the hinge assembly 200 will be described below with reference to Figures 3 to 4B and described.

[0056] The display panel 130 is disposed on the first set of housings 110 and the second set of housings 120. Specifically, the display panel 130 is disposed on one surface of the first support member 112 and the second support member 122. The display panel 130 may be one of various display panels 130 such as an organic light emitting display panel or a liquid crystal display panel.

[0057] Although not shown in the drawings, the display panel 130 is a configuration for displaying an image to a user and includes a plurality of sub-pixels. In the display panel 130, a plurality of scan lines and a plurality of data lines intersect each other, and each of the plurality of sub-pixels may be connected to the scan line and the data line. In addition, each of the plurality of sub-pixels may be connected to a high potential power line, a low potential power line, an initialization signal line, and an emission control signal line.

[0058] A sub-pixel is the smallest unit constituting the screen, and each of the plurality of sub-pixels may include a light emitting diode and a pixel circuit for driving the light emitting diode. The plurality of light emitting diodes may be defined in different ways according to the type of the display panel 130. For example, when the display panel 130 is an organic light emitting display panel, the light emitting diode may be an organic light emitting diode including an anode, a light emitting unit, and a cathode. Hereinafter, although the description will be made on the assumption that the light emitting diode is an organic light emitting diode, the type of the light emitting diode is not limited thereto.

[0059] The pixel circuit is a circuit for controlling the driving of the light emitting diode. For example, the pixel circuit may be configured to include a plurality of transistors and capacitors, but is not limited thereto.

[0060] In addition, the display panel 130 may be flexible and be folded and unfolded according to the folding and unfolding of the foldable display device 100.

[0061] The foldable display device 100 may be folded such that the first set of housings 110 and the second set of housings 120 form a specific folding angle. That is, although in Figure 1 and Figure 2 , the first set of housings 110 and the second set of housings 120 are fully unfolded at 180°, the foldable display device 100 may be folded at a specific angle. In this case, the display panel 130 on which the first set of housings 110 and the second set of housings 120 are disposed is also folded at a specific angle together with the folding of the first set of housings 110 and the second set of housings 120.

[0062] In addition, the foldable display device 100 may be maintained at a specific folding angle by the holding force provided from the hinge assembly 200. That is, the first set of housings 110 and the second set of housings 120 may be fixed while being maintained at a specific folding angle by the hinge assembly 200. Accordingly, the foldable display device 100 is folded at a specific angle according to the user's intention and is maintained in the folded state at a specific angle by the holding force of the hinge assembly 200.

[0063] The bezel cover 140 covers the upper bezel of the display panel 130 on the upper surface of the display panel 130. The bezel cover 140 is integrally formed to cover all the bezels of the display panel 130, but is not limited thereto. That is, the bezel cover 140 may be configured to be divided into a first bezel cover on the left side and a second bezel cover on the right side.

[0064] Hereinafter, Figures 3 to 4B a detailed description will be given of the specific structure and function of the hinge assembly 200.

[0065] Figure 3 is Figure 2 an exploded perspective view in which part A of Figure 3 shows an exploded perspective view of the hinge assembly 200. Figure 4A is a perspective view showing a first cam structure of a foldable display device according to an exemplary embodiment of the present disclosure. Figure 4B is a perspective view showing a support member and a gear housing of a foldable display device according to an exemplary embodiment of the present disclosure. Figure 5A is Figure 2 a cross-sectional view taken along line Va-Va' of Figure 5B is Figure 2 a cross-sectional view taken along line Vb-Vb' of

[0066] Referring to Figures 3 to 4B , the hinge assembly 200 according to an exemplary embodiment of the present disclosure includes: a middle rod 210, a first baffle rod 220a, a second baffle rod 220b, a fastening member 230, a first cam 240a, a second cam 240b, a support member 250, a spring member 260, a gear housing 270, a first rotating gear 280a, a second rotating gear 280b, a first gear arm 290a, and a second gear arm 290b.

[0067] Referring to Figure 2 , the middle rod 210 is disposed between the first set of housings 110 and the second set of housings 120. The middle rod 210 extends in the longitudinal direction (Y-axis direction or the second direction). The middle rod 210 has a flat upper surface to support the display panel 130.

[0068] Referring to Figure 3, both sides of the middle rod 210 in the width direction (X-axis direction or the first direction) have inwardly recessed surfaces to correspond to the protruding surfaces formed on one side of the first baffle rod 220a and the second baffle rod 220b. The curved surface of the middle rod 210 may have a shape corresponding to the arc formed on one side of the first baffle rod 220a and the second baffle rod 220b.

[0069] Two first insertion holes 212 are formed on both sides of the middle rod 210 in the length direction (Y-axis direction). The first insertion holes 212 are fastened to a fastening member 230 adjacent in the length direction (Y-axis direction) by pins.

[0070] The middle rod 210 moves up and down in the thickness direction (Z-axis direction or the third direction). The middle rod moves up and down according to whether the first set of housings 110 and the second set of housings 120 are folded. The up and down movement of the middle rod 210 will be described in the case of folding an example of a foldable display device according to an exemplary embodiment of the present disclosure.

[0071] The first baffle rod 220a and the second baffle rod 220b are disposed on both sides of the middle rod 210 in the width direction (X-axis direction). Refer to Figure 2 , the first baffle rod 220a is disposed between the middle rod 210 and the first set of housings 110, and the second baffle rod 220b is disposed between the middle rod 210 and the second set of housings 120. The first baffle rod 220a and the second baffle rod 220b support a part of the display panel 130 and serve as hinges. The first baffle rod 220a and the second baffle rod 220b rotate about a rotation axis in the length direction (Y-axis direction) located on the side adjacent to the middle rod 210.

[0072] The first baffle rod 220a and the second baffle rod 220b have a wing shape. Refer to Figure 3 , the first baffle rod 220a and the second baffle rod 220b are formed such that the thickness decreases from the inside to the outside in the width direction (X-axis direction). The first baffle rod 220a and the second baffle rod 220b achieve a movement in which the thin outer side rotates about a rotation axis located at the thick inner side.

[0073] One side of the first baffle rod 220a and the second baffle rod 220b adjacent to the middle rod 210 has a protruding surface. Refer to Figure 3, the right side of the first baffle rod 220a and the left side of the second baffle rod 220b have convex surfaces. The right side of the first baffle rod 220a and the left side of the second baffle rod 220b form an arc relative to the rotation axis. The curved surfaces formed on one side of the first baffle rod 220a and the second baffle rod 220b correspond to the side surfaces of the middle rod 210. The convex surfaces formed on one side of the first baffle rod 220a and the second baffle rod 220b at least partially correspond to the concave surfaces formed on the side of the middle rod 210. The central axis of the convex surfaces formed on one side of the first baffle rod 220a and the second baffle rod 220b at least partially corresponds to the concave surfaces formed on the side surface of the middle rod 210.

[0074] The other sides of the first baffle rod 220a and the second baffle rod 220b have various shapes. Although Figure 3 shows a structure in which the other sides of the first baffle rod 220a and the second baffle rod 220b adjacent to the first set of housings 110 and the second set of housings 120 form an arc with a smaller radius of curvature than their one side, it is not limited thereto. That is, the other sides of the first baffle rod 220a and the second baffle rod 220b form curved surfaces or may have a rectangular or polygonal shape.

[0075] The second insertion holes 224a and 224b may be formed in the corresponding sides of the first baffle rod 220a and the second baffle rod 220b adjacent to the middle rod 210 in the width direction (X-axis direction), and may be fastened to the adjacent fastening members 230 in the length direction (Y-axis direction). The second insertion holes 224a and 224b are fastened to the adjacent fastening members 230 in the length direction (Y-axis direction) by pins, and the first baffle rod 220a and the second baffle rod 220b cooperate with the middle rod 210 connected to the fastening members 230.

[0076] The sliding pins 222a and 222b (examples of the first sliding pin and the second sliding pin) are formed on both sides of one side of the first baffle rod 220a and the second baffle rod 220b adjacent to the first set of housings 110 and the second set of housings 120 in the length direction (Y-axis direction). The sliding pins 222a and 222b are inserted into the guide holes 241 (in Figure 5B , 241a and 241b, which are examples of the first guide hole and the second guide hole) of the cams 240a and 240b to be described below to slide along the guide holes 241. The sliding pins 222a and 222b are integrally formed with the first baffle rod 220a and the second baffle rod 220b, and may be pins inserted into pre-formed third insertion holes formed in the first baffle rod 220a and the second baffle rod 220b.

[0077] The fastening members 230 are arranged on the outside of the middle rod 210 in the length direction (Y-axis direction). Refer toFigure 3 The fastening member 230 has four fourth insertion holes 232. Among the four fourth insertion holes, two of the fourth insertion holes therein are fastened to the first insertion hole 212 of the middle rod 210, and the other two remaining fourth insertion holes located on the outside can be fastened to the second insertion holes 224a and 224b of the first baffle rod 220a and the second baffle rod 220b. The middle rod 210, the first baffle rod 220a, and the second baffle rod 220b are integrated by the fastening member 230 to cooperate with each other.

[0078] Two of the fourth insertion holes located in the fastening member 230 are fastened to the support member 250. That is, two of the fourth insertion holes located in the fastening member 230 are fastened to the middle rod 210 on one side in the longitudinal direction (Y-axis direction), and are fastened to the support member 250 on the other side. By doing so, the middle rod 210 can cooperate with the support member 250.

[0079] The support member 250 is disposed outside the fastening member 230 along the longitudinal direction (Y-axis direction). The support member 250 moves up and down according to the rotation of the cam to be described below. In addition, the support member 250 is coupled to the fastening member 230 on one side and contacts the gear housing 270 on the other side.

[0080] Refer to Figure 4B The support member 250 may include a flat portion 252, an arc portion 254, and a protrusion portion 256. The flat portion 252 is located at the center of the upper surface of the support member 250 and contacts the first protrusion portions 243 of the first cam 240a and the second cam 240b by the rotation of the first cam 240a and the second cam 240b to be described below. The arc portions 254 are located on both sides of the flat portion 252 and have a convex surface. That is, the arc portions 254 form an arc with respect to the central axis. The arc portions 254 may contact the bent portions 245 of the first cam 240a and the second cam 240b to be described below. The arc portions 254 contact the bent portions 245 of the first cam 240a and the second cam 240b to support the first cam 240a and the second cam 240b when the first cam 240a and the second cam 240b rotate. The protrusion portion 256 has a shape protruding toward the gear housing 270. The protrusion portion 256 is inserted into the guide groove 272 formed in the gear housing 270 to move up and down.

[0081] The first cam 240a and the second cam 240b are disposed on both sides of the support member 250 along the width direction (X-axis direction). Refer to Figure 4A Each of the first cam 240a and the second cam 240b includes a fixed portion FP and a pressing portion PP.

[0082] The fixing part FP is connected to the adjacent baffle rods 220a and 220b and the gear arms 290a and 290b. Specifically, the fixing part FP includes a guide hole 241 and a fastening hole 242. The sliding pins 222a and 222b of the baffle rods 220a and 220b are inserted into the guide hole 241. When the first cam 240a and the second cam 240b rotate, the sliding pins 222a and 222b move along the guide hole 241 of the fixing part FP, so that the first baffle rod 220a and the second baffle rod 220b can rotate with a margin. A plurality of fastening holes 242 can be provided. For example, referring to Figure 4A , there are two fastening holes 242 with the guide hole 241 located therebetween, spaced at the same interval from the guide hole 241. The fastening holes 242 can be fastened to the first gear arm 290a and the second gear arm 290b through fastening pins.

[0083] When the first cam 240a and the second cam 240b rotate, the pressing part PP applies pressure to the upper surface of the support member 250 disposed between the first cam 240a and the second cam 240b. Referring to Figure 4A , the pressing part PP includes a first protrusion 243, a second protrusion 244, and a bending part 245.

[0084] The first protrusion 243 extends from the fixing part FP in the width direction (X-axis direction) with respect to the unfolded state of the foldable display device. That is, the first protrusion 243 is a part extending from the fixing part FP toward the adjacent support member 250. Through the rotational movement of the first cam 240a and the second cam 240b, the first protrusion 243 applies downward pressure to the flat part 252 of the support member 250, so that the support member 250 moves downward. That is, the up-and-down movement of the support member 250 is achieved through the movement of the first protrusion 243.

[0085] The second protrusion 244 has a structure extending in the thickness direction (Z-axis direction). The bending part 245 is formed between the first protrusion 243 and the second protrusion 244. The bending part 245 corresponds to the arc part 254 of the support member 250. The bending part 245 has a concave surface. The bending part 245 contacts the arc part 254 of the support member 250. When the first cam 240a and the second cam 240b rotate, the bending part 245 rotates and supports the arc part 254. The movement of the first cam 240a and the second cam 240b in the inward folding, outward folding, and unfolded states will be described below with reference to Figures 5A to 7B the movement of the first cam 240a and the second cam 240b in the inward folding, outward folding, and unfolded states.

[0086] The spring member 260 is disposed on the lower surface of the flat portion 252 of the support member 250 and on the support unit 273 of the gear housing 270 to transmit an upward pressure to the support member 250. When the support member 250 moves downward by the rotational movement of the first cam 240a and the second cam 240b, the spring member 260 transmits pressure to restore the support member 250 to its original position.

[0087] The gear housing 270 is disposed outside the support member 250 in the longitudinal direction (Y-axis direction). The gear housing 270 houses and protects the first rotating gear 280a and the second rotating gear 280b, and supports the adjacent spring member 260.

[0088] Referring Figure 3 and Figure 4B , the gear housing 270 includes a housing unit 271, a guide groove 272, a support unit 273, and a fixing groove 274. The housing unit 271 is formed on one side of the gear housing 270 in the longitudinal direction (Y-axis direction) to house the first rotating gear 280a and the second rotating gear 280b. The guide groove 272 is formed on the opposite surface of the housing unit 271, that is, on the other side of the gear housing 270 in the longitudinal direction (Y-axis direction). The guide groove 272 has a shape in which a portion on the other side of the gear housing 270 is recessed. The guide groove 272 is formed to extend in the thickness direction (Z-axis direction), but is not limited thereto. The protrusion 256 of the support member 250 is inserted into the guide groove 272 to move up and down. The support unit 273 is located below the surface on which the guide groove 272 is formed. The support unit 273 may have a plate shape extending from the other side of the gear housing 270 toward the support member 250. The fixing groove 274 is formed in the support unit 273. The spring member 260 is inserted into the fixing groove 274 to be fixed.

[0089] The support unit 273 and the fixing groove 274 of the gear housing 270 enable the spring member 260 to transmit pressure to the support member 250 without being deviated by an external impact force during movement. In addition, the guide groove 272 of the gear housing 270 enables the support member 250 to move up and down constantly without deviation.

[0090] The first rotating gear 280a and the second rotating gear 280b are disposed in the gear housing 270. The first rotating gear 280a and the second rotating gear 280b serve as rotating shafts for rotating the first gear arm 290a and the second gear arm 290b coupled to the first group of housings 110 and the second group of housings 120. Referring Figure 3 , the first rotating gear 280a and the second rotating gear 280b have a circular cross-section at the edge portion and a tooth shape at the center portion. The first rotating gear 280a and the second rotating gear 280b mesh with each other. Figure 3The rotating gear shown is a two-axis gear composed of two rotating gears, but it is not limited thereto. For example, the rotating gear is a four-axis gear composed of four rotating gears.

[0091] The first gear arm 290a and the second gear arm 290b are disposed outside the first rotating gear 280a and the second rotating gear 280b in the longitudinal direction (Y-axis direction). The first gear arm 290a and the second gear arm 290b couple the hinge assembly 200 to the first set of housings 110 and the second set of housings 120 to fold and unfold the first set of housings 110 and the second set of housings 120 relative to the hinge assembly 200.

[0092] Referring to Figure 3 , the first gear arm 290a and the second gear arm 290b include fastening holes 291a and 291b coupled to the first rotating gear 280a and the second rotating gear 280b and fastening units 292a and 292b coupled to the first set of housings 110 and the second set of housings 120. When the first rotating gear 280a and the second rotating gear 280b rotate relative to a pair of rotating shafts, the first gear arm 290a and the second gear arm 290b rotate. The fastening units 292a and 292b of the first gear arm 290a and the second gear arm 290b are fastened to the first fastening unit 116 of the first set of housings 110 and the second fastening unit 126 of the second set of housings 120. Accordingly, the set of housings and other components accommodated in the set of housings can be folded and unfolded according to the movement of the hinge assembly 200.

[0093] Hereinafter, with reference to Figures 5A to 7B , the structure and movement of the main components of the hinge assembly when the foldable display device 100 is folded and unfolded will be described in detail.

[0094] Figure 5A and Figure 5B are schematic cross-sectional views showing an unfolded state of a foldable display device according to another exemplary embodiment of the present disclosure. Figure 5A is a cross-sectional view taken along line Va-Va' of Figure 2 . Figure 5B is a cross-sectional view taken along line Vb-Vb' of Figure 2 . Figure 6A and Figure 6B are schematic cross-sectional views showing an outward-folded state of a foldable display device according to an exemplary embodiment of the present disclosure. Figure 7A and Figure 7B are schematic cross-sectional views showing an inward-folded state of a foldable display device according to an exemplary embodiment of the present disclosure.

[0095] Shows Figure 5A and Figure 5BThe foldable display device shown is in the unfolded state, i.e., the first set of housings and the second set of housings are fully unfolded at an angle of 180°.

[0096] Referring to Figure 5A and Figure 5B , the first set of housings and the second set of housings are fully unfolded at 180°. The first cam 240a and the second cam 240b coupled to the first set of housings and the second set of housings are fully unfolded at 180°, and the first protrusions of the first cam 240a and the second cam 240b do not contact the flat portion 252 of the support member 250. Accordingly, by the elastic force of the spring member 260, the middle rod 210 coupled to the fastening member 230 and the support member 250 are disposed in the same plane as the adjacent first baffle rod 220a and the second baffle rod 220b. By doing so, as Figure 5A shown, the middle rod 210, the first baffle rod 220a, and the second baffle rod 220b substantially form a flat upper surface, and the display panel 130 located on the set of housings and the middle rod 210, the first baffle rod 220a, and the second baffle rod 220b also remains in a flat state.

[0097] Illustrated is Figure 6A and Figure 6B the foldable display device shown being folded outward, i.e., the first set of housings and the second set of housings are fully folded backward so that the display panel is disposed on the outside.

[0098] Referring to Figure 6A and Figure 6B , the first set of housings and the second set of housings are folded downward by approximately 90° relative to the Figure 5A and Figure 5B shown unfolded state so that the display panel 130 is disposed on the outside. As Figure 6B shown, the first cam 240a and the second cam 240b coupled to the first set of housings and the second set of housings are also folded downward by approximately 90°, and support the arc portion 254 of the support member 250. The first baffle rod 220a and the second baffle rod 220b coupled through the guide holes 241 of the first cam 240a and the second cam 240b are also folded downward by approximately 90°. As Figure 6A and Figure 6B shown, the first protrusions 243a and 243b of the first cam 240a and the second cam 240b do not contact the flat portion 252 of the support member 250. Accordingly, as Figure 6A shown, the middle rod 210 coupled to the fastening member 230 and the support member 250 do not move up and down by the elastic force of the spring member 260, but remain in their original positions. At this time, the first baffle rod 220a and the second baffle rod 220b are folded downward so that the display panel 130 is folded downward and outward by approximately 90° from the upper surface of the middle rod 210 along the curved surface of one side of the first baffle rod and the second baffle rod.

[0099] At this time, the display panel 130 in the folding area is supported by the middle rod 210, so that even when subjected to external impacts and pressures during outward folding, dents in the display panel 130 are suppressed. In addition, referring to Figure 6A , one side of the first baffle rod 220a and the second baffle rod 220b maintains a curved shape C instead of an angular shape. A rounded rectangle is formed by folding the first baffle rod 220a and the second baffle rod 220b. By doing so, the middle rod 210 and the display panel 130 provided along the upper surfaces of the first baffle rod 220a and the second baffle rod 220b are folded along the curved shape, so that even when outward folding is repeatedly performed, cracks and creases in the folding area are minimized.

[0100] In addition, referring to Figure 6A , during outward folding, the lengths V of the baffle rods 220a and 220b from the rotation axis in the upward direction or the vertical direction (Z-axis direction) and the length H in the lateral direction or the horizontal direction (X-axis direction) satisfy the following Equation 1. The stress concentrated on the display panel during outward folding can vary according to the size of the angle with which the display panel 130 is in direct contact.

[0101] [Equation 1]

[0102] Or

[0103] When the length V of the baffle rods 220a and 220b from the rotation axis in the upward direction is greater than the length H in the lateral direction, during outward folding, the stress applied to the portion in contact with the baffle rods 220a and 220b when the display panel 130 is folded can be reduced. In contrast, when the length H of the baffle rods 220a and 220b from the rotation axis in the lateral direction is greater than the length V in the upward direction, the stress applied to the display panel corresponding to the inside of the support member 250 can be reduced. That is, the length H of the baffle rods 220a and 220b from the rotation axis in the lateral direction and the length V in the upward direction have a trade-off relationship, so that the lengths can be set by considering the total stress applied to the entire display panel. When the length H of the baffle rods 220a and 220b from the rotation axis in the lateral direction and the length V in the upward direction satisfy the range of Equation 1, the stress applied to the display panel during outward folding is completely reduced, so that the performance of the display panel can be maintained for a long time.

[0104] It shows that Figure 7A and Figure 7B the foldable display device shown in is folded inward, that is, the first set of housings and the second set of housings are completely folded so that the display panel is disposed therein.

[0105] Referring to Figure 7A andFigure 7B , the first set of housings and the second set of housings are folded upward by approximately 90° relative to Figure 5A and Figure 5B the unfolded state shown, such that the display panel 130 is disposed therein. As Figure 7B shown, the first cam 240a and the second cam 240b coupled to the first set of housings and the second set of housings are folded upward by approximately 90°. At this time, the first protrusions 243a and 243b of the first cam 240a and the second cam 240b apply downward pressure to the flat portion 252 of the support member 250. Due to the pressure applied to the support member 250, the support member 250 moves downward, and the first cam 240a and the second cam 240b are folded upward and the first protrusions 243a and 243b of the first cam 240a and the second cam 240b come into contact with the flat portion 252 of the support member 250. The first shutter bars 220a and the second shutter bars 220b coupled through the guide holes of the first cam 240a and the second cam 240b are also folded upward. At this time, referring to Figure 7B , when the first cam 240a and the second cam 240b are folded upward, they are subjected to a force in the upward direction. Therefore, unlike the first cam 240a and the second cam 240b that are folded by approximately 90°, the sliding pins 222a and 222b of the first shutter bars 220a and the second shutter bars 220b move outward along the guide holes of the first cam 240a and the second cam 240b. Therefore, the first shutter bars 220a and the second shutter bars 220b are not folded by 90° but are located at a position higher than the first cam 240a and the second cam 240b. Therefore, as Figure 7A shown, the first support member 112 and the second support member 122 coupled to the first cam 240a and the second cam 240b are located inside the first shutter bars 220a and the second shutter bars 220b.

[0106] Therefore, the first support member 112, the second support member 122, the first shutter bars 220a and the second shutter bars 220b form a space S in the folded state, and the display panel 130 is disposed in the shape of omega (Ω). When the display panel 130 is folded in the shape of omega (Ω), the radius of curvature increases, such that the stress applied to the folded display panel 130 can be reduced.

[0107] In addition, the curved surface of the display panel 130 that is folded inward is supported by the support member 250 that moves downward to suppress a decrease in the radius of curvature of the display panel 130. Therefore, even when the inward folding is repeatedly implemented, cracks or creases caused in the display panel corresponding to the folding layer can be suppressed.

[0108] Figure 8A and Figure 8BIt is a schematic cross-sectional view showing an inwardly folded state of a foldable display device according to another exemplary embodiment of the present disclosure.

[0109] Referring to Figure 8A and Figure 8B , a foldable display device according to another exemplary embodiment of the present disclosure is substantially the same as the foldable display device 100 shown in Figure 7A and Figure 7B , except that the first cam 340a and the second cam 340b have different structures, such that in the inwardly folded state of the foldable display device, the folding angles of the first baffle rod 320a and the second baffle rod 320b are different, and the folding shape of the display panel 330 is different. Therefore, redundant descriptions will be omitted.

[0110] Shows Figure 8A and Figure 8B the foldable display device shown in is in an inwardly folded state, that is, the first set of housings 110 and the second set of housings 120 are fully folded such that the display panel 330 is disposed therein. Referring to Figure 8A and Figure 8B , the first set of housings 110 and the second set of housings 120 are folded by approximately 90° in the upward direction (Z-axis direction) relative to the unfolded state such that the display panel 330 is disposed therein. As shown in Figure 8B , the first cam 340a and the second cam 340b coupled to the first set of housings 110 and the second set of housings 120 are also folded by approximately 90° in the upward direction (Z-axis direction).

[0111] Referring to Figure 8A , the display panel 330 is folded in an "Ω" shape in the space formed by the first baffle rod 320a and the second baffle rod 320b. Different from the foldable display device 100 shown in Figure 7A , in Figure 8A , the foldable display device can be folded such that the folding angle θ1 of the first baffle rod 320a and the second baffle rod 320b is larger, and the interval between the first baffle rod 320a and the second baffle rod 320b is smaller. More specifically, in the inwardly folded state, the interval d1 between the first point P1 where the first baffle rod 320a contacts the display panel 330 and the second point P2 where the second baffle rod 320b contacts the display panel 330 may be 4 mm to 5 mm or 4.3 mm to 4.7 mm. In this case, the maximum distance d2 between the two upper surfaces of the display panel 330 opposite to each other at the first point P1 and the second point P2 may be 3.2 mm to 3.8 mm or 3.4 mm to 3.6 mm. That is, the maximum interval d2 in the omega (Ω) shape of the display panel 330 may be 3.2 mm to 3.8 mm or 3.4 mm to 3.6 mm.

[0112] Unlike Figure 7A the foldable display device 100 shown, as Figure 8A shown, when the size of the omega (Ω) shape of the folded display panel 330 is reduced by adjusting the interval between the first baffle bar 320a and the second baffle bar 320b, the stress applied at the point where the display panel 330 contacts the first baffle bar 320a and the second baffle bar 320b during outward folding can be reduced. More specifically, referring to Figure 6A , during outward folding in which the first baffle bar 320a and the second baffle bar 320b rotate downward so that the display panel 330 is disposed on the outside, the first baffle bar 320a and the second baffle bar 320b are folded downward. Accordingly, one side portion of the first baffle bar 320a and the second baffle bar 320b maintains a curved shape C instead of an angular shape. At this time, the display panel 330 is folded downward and outward along the curved shape C formed by the first baffle bar 320a and the second baffle bar 320b. The display panel 330 is in direct contact with the curved shape C formed on one side portion of the first baffle bar 320a and the second baffle bar 320b, and is folded at a large angle at this portion. Accordingly, a large stress is concentrated on the portion where the display panel 330 contacts the first baffle bar 320a and the second baffle bar 320b. At this time, a large compressive strain is applied to the portion where the display panel 330 contacts the first baffle bar 320a and the second baffle bar 320b during inward folding during the above-mentioned outward folding. When the display panel 330 is repeatedly folded inward and outward, this portion may be damaged. Accordingly, in the foldable display device according to another exemplary embodiment of the present disclosure, when the maximum interval d2 in the omega (Ω) shape of the display panel 330 satisfies the above range during inward folding, the compressive strain applied during the inward folding operation is reduced in the portion where the display panel 330 contacts the first baffle bar 320a and the second baffle bar 320b during outward folding. Specifically, when the maximum interval d2 of the omega (Ω) shape of the display panel 330 changes from 4.5 mm to 3.5 mm, it can be confirmed that during the inward folding operation, the compressive strain applied to the portion where the display panel 330 contacts the first baffle bar 320a and the second baffle bar 320b is reduced by 15%.

[0113] To control the structure of the display panel 330 during inward folding, the structures of the first cam 340a and the second cam 340b can be adjusted. Specifically, in the foldable display device according to another exemplary embodiment of the present disclosure, Figure 8B the first cam 340a and the second cam 340b shown in Figure 7BThe guiding holes 341a and 341b (examples of the first guiding hole and the second guiding hole) having different shapes of the guiding holes of the first cam 240a and the second cam 240b shown in []. More specifically, Figure 8B The guiding holes 341a and 341b of the first cam 340a and the second cam 340b shown in [] include first ends EP1a and EP1b and second ends EP2a and EP2b. The sliding pins (examples of the first sliding pin and the second sliding pin) of the first baffle rod 320a and the second baffle rod 320b are located at the first ends EP1a and EP1b in the inward folding state, and the sliding pins are located at the second ends EP2a and EP2b in the outward folding state. That is, the first ends EP1a and EP1b are the ends of the guiding holes 341a and 341b adjacent to the rotation axes R1 and R2 of the first baffle rod 320a and the second baffle rod 320b. The second ends EP2a and EP2b are the ends of the guiding holes 341a and 341b positioned away from the rotation axes R1 and R2 of the first baffle rod 320a and the second baffle rod 320b. The first ends EP1a and EP1b determine the positions of the first baffle rod 320a and the second baffle rod 320b during inward folding, thereby controlling the interval between the first baffle rod 320a and the second baffle rod 320b.

[0114] Referring to Figure 8B , the gradient formed by the first ends EP1a and EP1b and the second ends EP2a and EP2b with respect to the imaginary line IL connecting the rotation axis R1 of the first baffle rod 320a and the rotation axis R2 of the second baffle rod 320b may be 2 to 3 or 2.25 to 2.75. More specifically, during inward folding, the ratio of the displacement Lx of the guiding holes 341a and 341b in the X-axis direction to the displacement Lz in the Z-axis direction may be 1:2 to 1:3 or 2:4.5 to 2:5.5. At the same time, the folding angle θ1 formed by the rotation axis R1 of the first baffle rod 320a and the first end EP1a of the first cam 340a and the folding angle formed by the rotation axis R2 of the second baffle rod 320b and the first end EP1b of the second cam 340b may be 93° to 97° respectively. That is, the folding angle formed by the rotation axis R1 of the first baffle rod 320a and the sliding pin of the first baffle rod 320a may be 93° to 97°. As described above, the folding angles and positions of the first baffle rod 320a and the second baffle rod 320b are adjusted by the structures of the guiding holes 341a and 341b of the first cam 340a and the second cam 340b. By doing so, the shape of the folded display panel 330 located between the first baffle rod 320a and the second baffle rod 320b can be controlled. The strain of the portion of the display panel where the maximum strain is applied during repeated inward folding and outward folding operations can be reduced by adjusting the omega shape of the folded display panel 330 during inward folding.

[0115] Exemplary embodiments of the present disclosure may also be described as follows:

[0116] According to one aspect of the present disclosure, a foldable display device is provided. The foldable display device includes: a first set of housings and a second set of housings that are disposed opposite to each other in a first direction; a hinge assembly disposed between the first set of housings and the second set of housings; and a display panel disposed above the first set of housings, the second set of housings, and the hinge assembly. The hinge assembly includes: a middle rod that extends in a second direction perpendicular to the first direction between the first set of housings and the second set of housings; a first baffle rod disposed between the first set of housings and the middle rod; a second baffle rod disposed between the second set of housings and the middle rod; a fastening member that fastens the middle rod, the first baffle rod, and the second baffle rod; a support member coupled to the fastening member; a first cam and a second cam disposed on both sides of the support member in the first direction, and including a fixing unit that cooperates with the first baffle rod and the second baffle rod and a pressing unit that protrudes from the fixing unit toward the support member; a spring member disposed below the support member; and a first gear arm and a second gear arm that are fastened to the fixing units of the first cam and the second cam.

[0117] Each of the first set of housings and the second set of housings may include: a support member disposed below the display panel, a frame disposed at an edge of the support member, and a fastening unit formed in the frame. The fastening unit of the first set of housings may be fastened to the first gear arm, and the fastening unit of the second set of housings may be fastened to the second gear arm.

[0118] The upper surface of the middle rod may have a flat shape, and the side surfaces of the middle rod adjacent to the first baffle rod and the second baffle rod may have inwardly recessed surfaces.

[0119] At least a part of the first side portions of the first baffle rod and the second baffle rod adjacent to the middle rod may have protruding surfaces corresponding to the side surfaces of the middle rod, and the first side portions of the first baffle rod and the second baffle rod may be fastened to the fastening member such that the second side portions of the first baffle rod and the second baffle rod opposite to the first side portions are rotatably movable about the first side portions as rotation axes.

[0120] In the unfolded state of the first baffle rod and the second baffle rod, the length V of the first side portions of the first baffle rod and the second baffle rod from the rotation axis in the horizontal direction and the length H of the first side portions in the vertical direction from the rotation axis may satisfy the following Equation 1.

[0121] [Equation 1]

[0122] Or

[0123] The first side portions of the first baffle rod and the second baffle rod may be coupled to the fastening member, and the second side portions of the first baffle rod and the second baffle rod may be coupled to the fixing units of the first cam and the second cam.

[0124] The fixing units of the first cam and the second cam may include guide holes extending in a 45-degree direction between the first direction and the second direction, and sliding pins formed at the second side portions of the first baffle rod and the second baffle rod may be inserted into the guide holes.

[0125] The sliding pins may slidably move in the guide holes during the folding movement and the unfolding movement.

[0126] Each of the fixing units of the first cam and the second cam may further include two fastening holes, the two fastening holes being arranged to be spaced apart from the guide holes by the same distance and the guide hole being located between the two fastening holes, and the fastening holes may be fastened to the first gear arm and the second gear arm.

[0127] The support member may include a flat portion provided on the upper surface and arc portions provided on both sides of the flat portion and having convex surfaces, and the pressing portions of the first cam and the second cam may include a first protruding portion protruding from the fixing unit in the first direction to elongate, a second protruding portion protruding in a direction perpendicular to the first protruding portion, and a bent portion located between the first protruding portion and the second protruding portion.

[0128] During the inward folding movement in which the display panel is disposed inside, the first fixing units of the first cam and the second cam may press the flat portion of the support member to move the support member downward.

[0129] During the outward folding movement in which the display panel is disposed outside, the first fixing units of the first cam and the second cam may be spaced apart from the flat portion of the support member, and the support member may maintain its position without moving up and down by the spring member.

[0130] The foldable display device may further include: a first rotating gear and a second rotating gear respectively coupled to the first gear arm and the second gear arm; and a gear housing accommodating the first rotating gear and the second rotating gear. The gear housing may include a support unit extending to the support member, and the spring member may be disposed on the support unit.

[0131] The gear housing may include a guide groove pointing to the support member and partially recessed, and a protruding portion of the support member may be inserted into the guide groove to move up and down along the guide groove.

[0132] In the inward folded state in which the display panel is disposed inside, the display panel may have an omega (Ω) shape.

[0133] In the inward folding state where the display panel is disposed inside, the interval between the first point where the first baffle rod contacts the display panel and the second point where the second baffle rod contacts the display panel may be 4 mm to 5 mm.

[0134] The maximum distance between two opposite upper surfaces of the display panel at the first point and the second point may be 3.2 mm to 3.8 mm.

[0135] One side portion of the first baffle rod and the second baffle rod may be fastened to the fastening member, and the other side portion of the first baffle rod and the second baffle rod is coupled to the fixing units of the first cam and the second cam. The fixing units of the first cam and the second cam may include guiding holes formed to allow a sliding pin formed at the other side portion of the first baffle rod and the second baffle rod to slidably move, and the guiding holes may include a first end portion and a second end portion. In the inward folding state where the display panel is disposed inside, the sliding pin is located at the first end portion, and in the outward folding operation state where the display panel is disposed outside, the sliding pin is located at the second end portion.

[0136] In the inward folding state where the display panel is disposed inside, the folding angles formed by the rotation axis of the first baffle rod and the first end portion of the first cam and the folding angles formed by the rotation axis of the second baffle rod and the first end portion of the second cam may be 93° to 97° respectively.

[0137] In the inward folding state where the display panel is disposed inside, the gradient formed by the first end portion and the second end portion with respect to an imaginary line connecting the rotation axes of the first baffle rod and the second baffle rod may be 2.25 to 2.75.

[0138] 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 may be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, providing the exemplary embodiments of the present disclosure is only for illustrative purposes and is 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 protection scope of the present disclosure should be interpreted based on the appended claims, and all technical concepts within the equivalent scope thereof should be interpreted as falling within the scope of the present disclosure.

Claims

1. A foldable display device, comprising: A first set of housings and a second set of housings, which are arranged opposite to each other in a first direction; A hinge assembly, which is arranged between the first set of housings and the second set of housings; And A display panel, which is arranged above the first set of housings, the second set of housings and the hinge assembly, Wherein, the hinge assembly includes: A middle rod, which extends in a second direction perpendicular to the first direction between the first set of housings and the second set of housings; A first baffle rod, which is arranged between the first set of housings and the middle rod; A second baffle rod, which is arranged between the second set of housings and the middle rod; A fastening member, which fastens to the middle rod, the first baffle rod and the second baffle rod; A support member, which is coupled to the fastening member; A first cam and a second cam, which are arranged on both sides of the support member along the first direction. The first cam includes a fixing unit that cooperates with the first baffle rod and a pressing unit that protrudes from the fixing unit toward the support member, and the second cam includes a fixing unit that cooperates with the second baffle rod and a pressing unit that protrudes from the fixing unit toward the support member; A spring member, which is arranged below the support member; and A first gear arm and a second gear arm, the first gear arm is fastened to the fixing unit of the first cam, and the second gear arm is fastened to the fixing unit of the second cam.

2. The foldable display device according to claim 1, wherein, Each of the first set of housings and the second set of housings includes: A support member arranged below the display panel, a frame formed at the edge of the support member, and a fastening unit formed in the frame, The fastening unit of the first set of housings is fastened to the first gear arm, and the fastening unit of the second set of housings is fastened to the second gear arm.

3. The foldable display device according to claim 1, wherein, The upper surface of the middle rod has a flat shape, and the side surfaces of the middle rod adjacent to the first baffle rod and the second baffle rod have inwardly concave surfaces.

4. The foldable display device according to claim 3, wherein, At least a part of one side portion of the first baffle rod adjacent to the middle rod has a protruding surface corresponding to the side surface of the middle rod, and the one side portion of the first baffle rod is fastened to the fastening member, so that the other side portion of the first baffle rod can rotate and move with the one side portion of the first baffle rod as a rotation axis, and At least a part of one side portion of the second baffle rod adjacent to the middle rod has a protruding surface corresponding to the side surface of the middle rod, and the one side portion of the second baffle rod is fastened to the fastening member, so that the other side portion of the second baffle rod can rotate and move with the one side portion of the second baffle rod as a rotation axis.

5. The foldable display device according to claim 4, wherein, In the outwardly folded state of the first baffle rod and the second baffle rod, a side portion of the first baffle rod is at distances V and H from the rotation axis corresponding to the first baffle rod in the vertical direction and the horizontal direction, respectively, a side portion of the second baffle rod is at distances V and H from the rotation axis corresponding to the second baffle rod in the vertical direction and the horizontal direction, respectively, and V and H satisfy the following equation 1: or 6. The foldable display device according to claim 4, wherein, One side portion of the first baffle rod and one side portion of the second baffle rod are coupled to the fastening member, the other side portion of the first baffle rod is coupled to the fixing unit of the first cam, and the other side portion of the second baffle rod is coupled to the fixing unit of the second cam.

7. The foldable display device according to claim 6, wherein, The fixing unit of the first cam includes a first guiding hole extending in a 45-degree direction between the first direction and the second direction, and a first sliding pin formed at the other side portion of the first baffle rod is inserted into the first guiding hole, and wherein the fixing unit of the second cam includes a second guiding hole extending in a 45-degree direction between the first direction and the second direction, and a second sliding pin formed at the other side portion of the second baffle rod is inserted into the second guiding hole.

8. The foldable display device according to claim 7, wherein, During the folding movement and the unfolding movement, the first sliding pin slidably moves in the first guiding hole and the second sliding pin slidably moves in the second guiding hole.

9. The foldable display device according to claim 7, wherein, The fixing unit of the first cam further includes two fastening holes which are arranged to be spaced apart from the first guiding hole by the same distance and are fastened to the first gear arm, the first guiding hole being located between the two fastening holes, and wherein the fixing unit of the second cam further includes two fastening holes which are arranged to be spaced apart from the second guiding hole by the same distance and are fastened to the second gear arm, the second guiding hole being located between the two fastening holes.

10. The foldable display device according to claim 1, wherein, The support member includes a flat portion provided on the upper surface and arc portions provided on both sides of the flat portion and having convex surfaces, and The pressing portions of the first cam and the second cam each include a first protruding portion protruding in the first direction from the fixing unit to elongate, a second protruding portion protruding in a direction perpendicular to the first protruding portion, and a bent portion located between the first protruding portion and the second protruding portion.

11. The foldable display device according to claim 10, wherein, During the inward folding movement in which the display panel is disposed inside, the fixing units of the first cam and the second cam press the flat portion of the support member to move the support member downward.

12. The foldable display device according to claim 10, wherein, During the outward folding movement in which the display panel is disposed outside, the fixing units of the first cam and the second cam are spaced apart from the flat portion of the support member, and the support member maintains the position of the support member without moving up and down by a spring member.

13. The foldable display device according to claim 1, further comprising: A first rotating gear and a second rotating gear which are respectively coupled to the first gear arm and the second gear arm; And A gear housing that houses the first rotating gear and the second rotating gear, wherein the gear housing includes a support unit extending to the support member, and the spring member is disposed on the support unit.

14. The foldable display device according to claim 13, wherein, The gear housing includes a guide groove that points to the support member and is partially recessed, and a protrusion of the support member is inserted into the guide groove to move up and down along the guide groove.

15. The foldable display device according to claim 1, further comprising a bezel cover that covers an upper bezel of the display panel on an upper surface of the display panel.

16. The foldable display device according to claim 1, wherein, In an inwardly folded state where the display panel is disposed inside, the display panel has an omega (Ω) shape.

17. The foldable display device according to claim 16, wherein, In an inwardly folded state where the display panel is disposed inside, a distance between a first point where the first baffle bar and the display panel come into contact with each other and a second point where the second baffle bar and the display panel come into contact with each other is 4 mm to 5 mm.

18. The foldable display device according to claim 17, wherein, A maximum distance between two opposite upper surfaces of the display panel at the first point and the second point is 3.2 mm to 3.8 mm.

19. The foldable display device according to claim 1, wherein, One side portion of the first baffle bar is fastened to the fastening member, and the other side portion of the first baffle bar is coupled to a fixing unit of the first cam. The fixing unit of the first cam includes a first guide hole formed to allow a first sliding pin formed at the other side portion of the first baffle bar to slidably move, and the first guide hole includes a first end portion and a second end portion. In an inwardly folded state where the display panel is disposed inside, the first sliding pin is located at the first end portion, and in an outward folding operation state where the display panel is disposed outside, the first sliding pin is located at the second end portion, and One side portion of the second baffle bar is fastened to the fastening member, and the other side portion of the second baffle bar is coupled to a fixing unit of the second cam. The fixing unit of the second cam includes a second guide hole formed to allow a second sliding pin formed at the other side portion of the second baffle bar to slidably move, and the second guide hole includes a first end portion and a second end portion. In an inwardly folded state where the display panel is disposed inside, the second sliding pin is located at the first end portion, and in an outward folding operation state where the display panel is disposed outside, the second sliding pin is located at the second end portion.

20. The foldable display device according to claim 19, wherein, In an inwardly folded state where the display panel is disposed inside, a folding angle formed by a rotation axis of the first baffle bar and a first end portion of the first cam and a folding angle formed by a rotation axis of the second baffle bar and a first end portion of the second cam are 93° to 97° respectively.

21. The foldable display device according to claim 19, wherein, In the inward folding state where the display panel is disposed inside, the gradient formed by the first end portion and the second end portion with respect to an imaginary line connecting the rotation axis of the first damper rod and the rotation axis of the second damper rod is 2.25 to 2.

75.

22. A hinge structure for a foldable display device, comprising: A middle rod extending in a second direction; A first damper rod disposed on one side of the middle rod and extending in the second direction; A second damper rod disposed on the other side of the middle rod and extending in the second direction; A fastening member fastening to the middle rod, the first damper rod, and the second damper rod; A support member coupled to the fastening member; A first cam and a second cam disposed on both sides of the support member in a first direction perpendicular to the second direction, the first cam including a fixing unit that cooperates with the first damper rod and a pressing unit protruding from the fixing unit toward the support member, and the second cam including a fixing unit that cooperates with the second damper rod and a pressing unit protruding from the fixing unit toward the support member; A spring member disposed below the support member; A first gear arm fastened to the fixing unit of the first cam; And A second gear arm fastened to the fixing unit of the second cam.

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