Flexible display device and electronic device comprising this

Abstract

Flexible display device, including: a display panel (100); a lower plate (200) formed from a stainless steel material, wherein the lower plate (200) comprises a first surface facing a bottom of the display panel (100), wherein the lower plate (200) is divided into at least one folding area (FR, BR) and at least one non-folding area (UFR, UBR) adjacent to the folding area (FR, BR), wherein the folding area (FR, BR) has a mass per unit volume that is less than a mass per unit volume of the non-folding area (UFR, UBR); and several gears (510) under the folding area (FR, BR) of the lower plate (200), a support frame (450) to support the lower plate (200) around the gears (510) in the folding area (FR, BR); a magnetic body group (300, 1300) that is contained in the folding region (FR, BR) and the non-folding region (UFR, UBR), wherein the magnetic body group (300, 1300) is in contact with a second surface of the lower plate (200) that is opposite to the first surface of the lower plate (200). wherein the lower plate (200) comprises several slots (202) formed in the folding area (FR, BR); and wherein the magnetic body group (300, 1300) is in the folding area (FR, BR) between the lower plate (200) and the support frame (450).

Description

[0001] This application claims priority over Korean patent application No. 10-2017-0096363, which was filed on July 28, 2017. BACKGROUND OF THE INVENTION Area of ​​the invention

[0002] The present invention relates to a flexible display device, and in particular a flexible display device which, despite frequent folding and unfolding operations, exhibits improved reliability and facilitates a post-processing process, and to an electronic device which incorporates this. Discussion of the state of the art

[0003] A display device that presents various pieces of information on a screen is a core technology of the information and communication age and is constantly evolving to become thinner, lighter, more portable, and more powerful. For example, an organic light-emitting display device, which uses a self-illuminating organic light-emitting element and therefore does not require a separate light source, is attracting attention as a flat-panel display device capable of overcoming the problems of the cumbersome weight and bulk of a cathode ray tube (CRT).

[0004] Such an organic light-emitting display device displays an image using multiple pixels arranged in a matrix. Each pixel has a light-emitting element and a pixel drive circuit with multiple transistors that implement independent control of the light-emitting element.

[0005] Recently, there has been an increasing demand for flexible display devices for various applications. These devices can be conveniently carried in a pocket or purse and can display an image on a larger screen than when worn. A flexible display device is kept folded or bent when carried or stored and unfolds to display an image, thus increasing the image display area, improving the device's aesthetic appearance, and providing a more realistic image for the user.

[0006] A display panel for showing an image can be made thinner by reducing the thickness of the substrate. To protect the display panel from external moisture, stimulation, or physical shocks, it must be housed in an enclosure. Generally, the display panel and the enclosure are made of different materials, and the display panel and other components are housed together within the enclosure. Because the enclosure serves to hold various components, its size differs from that of the display panel. Furthermore, the thickness of the enclosure can vary depending on whether the components housed within it overlap. The display panel and the enclosure are manufactured using separate processes and are then assembled.Therefore, an adhesive element is provided between the display panel and the housing structure to prevent the display panel and the housing structure from separating due to vibrations or shocks.

[0007] However, in the case of a flexible display device where an adhesive element is provided at a folding area, the display panel may be undesirably bent, or the adhesive element may detach from the folding area. To avoid this problem, the adhesive element is removed from the folding area.

[0008] However, in the case of a flexible display device where an adhesive element is located away from the folding area, the force required to support the folding area is reduced. Therefore, when returning from the folded to the unfolded state, the display panel does not lie completely flat.

[0009] In previously developed flexible display devices, the folding area is separated from other areas after repeated folding and unfolding processes and is therefore visible from the outside, which leads to a deterioration of the aesthetic appearance of the device.

[0010] US 2016 / 0357052 A1 relates to a foldable display device and comprises a display panel and a backplate on a surface of the display panel, wherein the backplate comprises a folding area and unfolding areas on both sides of the folding area and the backplate has at least two different opening patterns in the folding area.

[0011] US 2015 / 0361696 A1 applies to devices such as computer equipment with hinged parts. An example may include a first and a second part, as well as a flexible display attached to the first and second parts. This example may also include a hinge assembly that rotatably secures the first and second parts. The hinge assembly may be fixed to the second part and movable to the first part, so that the length of the hinge assembly can change when the first and second parts are rotated relative to each other. BRIEF SUMMARY OF THE INVENTION

[0012] Accordingly, the present invention relates to a flexible display device and an electronic device containing it, which essentially avoid one or more problems caused by limitations and disadvantages of the prior art.

[0013] One object of the present invention is to provide a flexible display device that is able to keep a display panel stable despite repeated folding and unfolding operations, to prevent damage to the display panel during a post-processing process, and to facilitate the assembly of the display panel in a housing.

[0014] Another object of the present invention is to provide an electronic device comprising the above flexible display device.

[0015] Additional advantages, objectives, and features of the invention are partially set forth in the following description and will become apparent to the person skilled in the art upon examination of the following, or can be inferred from the embodiment of the invention. The objectives and other advantages of the invention can be realized and achieved through the structure, which is set forth in particular in the written description and the claims, as well as in the accompanying drawings.

[0016] These problems are solved by the subject matter of the independent claims. Further advantageous embodiments and developments are described in the respective dependent claims. In one aspect of the present disclosure, a flexible display device comprises a lower plate, provided beneath a display panel and having a predetermined stiffness, and a magnetic body group that is held in direct contact with the underside of the lower plate without any intervening adhesive element.

[0017] In one aspect of the present disclosure, a flexible display device comprises a display panel, a lower plate formed of stainless steel, the lower plate having a surface facing the underside of the display panel, the lower plate being divided into at least one folding area and a non-folding area adjacent to the folding area, the folding area having a density lower than the density of the non-folding area, and a magnetic body group divided in accordance with the folding area and the non-folding area, the magnetic body group being held in contact with the surface opposite the lower plate.

[0018] The magnetic body assembly can comprise a single magnetic body located in the non-folding area and at least two magnetic bodies located in the folding area. The magnetic body in the non-folding area and the at least two magnetic bodies can be separate from each other.

[0019] The magnetic body provided in the non-folding area and the at least two magnetic bodies provided in the folding area can be held in surface contact with the lower plate, and the contact area between the at least two magnetic bodies provided in the folding area and the lower plate can be smaller in a folded state than in an unfolded state.

[0020] The magnetic body provided in the non-folding area and the at least two magnetic bodies provided in the folding area may have flat surfaces to correspond to the lower plate.

[0021] The flexible display device may also have an adhesive layer provided between the display panel and the non-folding area of ​​one surface of the lower plate.

[0022] The lower plate may have several slots formed in the folding area.

[0023] The multiple slots can be arranged in multiple rows and multiple columns, with the rows being parallel to the folding axis, and the multiple slots formed in the adjacent rows may, viewed in a column direction, partially not overlap each other.

[0024] At least one of the slots formed in the folding area of ​​the lower plate can be formed with a depth that is less than the thickness of the non-folding area of ​​the lower plate.

[0025] The flexible display device may further comprise a metal film provided on the surface opposite the lower plate, which faces the magnet body group, wherein the metal film is brought into direct contact with the magnet body group.

[0026] Each of the at least two magnetic bodies provided in the folding area can be configured as a single body that extends continuously along the folding axis direction.

[0027] The magnetic body group can occupy an area that is more than 10% of the total area of ​​the non-folding region of the lower plate.

[0028] The flexible display device may further comprise a housing element for receiving the lower plate and the magnetic body assembly therein. The housing element may be connected to the underside of the magnetic body assembly by means of an adhesive element.

[0029] The housing element can have several segments provided according to the folding area, with the segments extending in the folding axis direction, and the magnet body group can be subdivided into the magnet bodies in accordance with the segments.

[0030] The flexible display device may also include a circuit board provided between the magnetic body group and the housing element to conform to the non-folding area.

[0031] The magnetic body group can be made of magnet steel.

[0032] The flexible display device can further comprise a flexible printed circuit board connected to one side of the display panel, wherein the flexible printed circuit board is arranged such that it is folded between the housing element and the magnet body group, a printed circuit board connected to the flexible printed circuit board, and a battery connected to the printed circuit board, wherein the battery is located between the housing element and the magnet body group.

[0033] The display panel can comprise a flexible base substrate, a thin-film transistor array provided on the flexible base substrate, an organic light-emitting diode array connected to the thin-film transistor array, an encapsulation layer for encapsulating the organic light-emitting diode array, a touch electrode array provided on the encapsulation layer, and a cover layer for protecting the touch electrode array.

[0034] In another aspect of the present disclosure, an electronic device comprises a display panel, a bottom plate formed of stainless steel, the bottom plate having a surface facing the underside of the display panel, the bottom plate being divided into at least one folding area and a non-folding area adjacent to the folding area, the folding area having a density lower than the density of the non-folding area, a magnetic body group being divided in accordance with the folding area and the non-folding area, the magnetic body group being held in contact with the surface opposite the bottom plate, a housing element for receiving the bottom plate and the magnetic body group therein, the housing element being divided in accordance with the non-folding area and the folding area in order to operate independently therein, and a flexible printed circuit board.which is connected to one side of the display panel, wherein the flexible printed circuit board extends to be folded between the housing element and the magnet body assembly, a printed circuit board connected to the flexible printed circuit board, wherein the printed circuit board is located between the housing element and the magnet body assembly, and a battery connected to the printed circuit board, wherein the battery is located between the housing element and the magnet body assembly.

[0035] It is understood that both the preceding general description and the following detailed description of the present invention are exemplary and explanatory and are intended to further explain the claimed invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are included to provide a further understanding of the invention and which form part of this application, illustrate one embodiment (version) of the invention and, together with the description, serve to explain the principle of the invention. The drawings include: Fig. Figure 1 is a perspective exploded view of a flexible display device according to a first embodiment of the present invention; Fig. 2 is a perspective view showing the coupled state of the in Fig. 1 flexible display device shown; Fig. 3 is a cross-sectional view along line II' in the unfolded state of the Fig. 1 flexible display device shown; Fig. 4 is a cross-sectional view along line II' in the state in which the Fig. 1 The flexible display device shown is folded halfway around a folding axis; Fig. Figure 5 is a cross-sectional view of a flexible display device according to another embodiment of the present invention, along line II-II' in Fig. 1; Fig. Figure 6 is a cross-sectional view of a display panel of the flexible display device; Fig. Figure 7 is a top view of a lower plate of the flexible display device; The Fig. 8A to 8D are cross-sectional views along line III-III' in Fig. 7; The Fig. Figures 9A to 9C are top views showing different embodiments of magnetic bodies that are brought into contact with the lower plate in the flexible display device according to the present invention; The Fig. 10A and Fig. Figures 10B are perspective views, each showing the unfolded state and the folded state of another exemplary folding area of ​​a housing element in the flexible display device according to the present invention; Fig. Figure 11 is a cross-sectional view showing an exemplary electronic device; Fig. Figure 12 is a perspective exploded view showing the unfolded state of a flexible display device according to a second embodiment. The Fig. 13A and Fig. Figure 13B shows cross-sectional views of a folding area and peripheral components in the unfolded and folded states of the [unclear text]. Fig. 12 display device shown; Fig. Figure 14 is an image showing the lower plate in the folded state in the flexible display device according to the present invention; Fig. Figure 15 is an image showing the folded state in which the lower plate and the magnetic body in the flexible display device according to the present invention are partially separated from each other; and Fig. Figure 16 is a view showing a magnetic body group and components arranged thereon in a flexible display device according to a second embodiment of the flexible display device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. In the drawings, identical or similar elements are designated by the same reference numerals, even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations included herein will be omitted if it could obscure the subject matter of the present invention.Before exemplary embodiments of the present invention are explained, it should be understood that the phraseology and terminology used in the following description and the attached claims is not to be interpreted as being limited to general and dictionary meanings, but rather as meanings and concepts in accordance with the spirit of the present invention, based on the principle that allows the inventor to define suitable terms for the best explanation.

[0038] It is understood that when an element, such as a layer, film, area, or substrate, is described as being "on" another element, it may be directly on top of that other element, or intervening elements may also be present. Conversely, when an element, such as a layer, film, area, or substrate, is described as being "directly on top of another element," this means that no intervening elements are present.

[0039] Additionally, for clearer illustration, the dimensions of elements such as thickness, width, or the like may be exaggerated or reduced in the drawings, and thus the thickness, width, or the like of the present invention is not limited to the representation in the drawings.

[0040] Exemplary embodiments of the present invention are described below with reference to the drawings.

[0041] The display devices according to the embodiments described herein can be a foldable display device whose center is foldable, or a bendable display device that is bendable in both directions. However, each part of the display device can be configured to be foldable or bendable. In the flexible display device according to the present invention, a lower plate and a magnetic body, which are folded or collapsed during a folding operation of the folding area, can be repositioned in accordance with the arrangement of the folding area of ​​the display device. The flexible display device according to the present invention can be referred to by various names, such as a foldable display device, a bendable display device, a rollable display device, etc., as long as the device is configured to be flexible.

[0042] Fig. Figure 1 is a perspective exploded view of a flexible display device according to a first embodiment of the present invention. Fig. 2 is a perspective view showing the coupled state of the in Fig. 1 represents the flexible display device shown. Fig. 3 is a cross-sectional view along line II' in the unfolded state of the Fig. 1 flexible display device shown. Fig. 4 is a cross-sectional view along line II' in the state in which the Fig. 1 The flexible display device shown is folded halfway around a folding axis.

[0043] As in the Fig. 1, Fig. 2, Fig. 3 to Fig. As shown in Figure 4, the flexible display device according to the first embodiment of the present invention comprises a display panel 100, a lower plate 200, a magnetic body group 300, and a housing element 400, which are arranged sequentially from above. This flexible display device according to the first embodiment of the present invention, as shown in Figure 4, comprises a display panel 100, a lower plate 200, a magnetic body group 300, and a housing element 400, which are arranged sequentially from above. Fig. 1, Fig. 2, Fig. 3 to Fig. Figure 4 shows a foldable display which can be folded such that an area of ​​it extending along line II-II' is folded halfway around the fold axis.

[0044] Due to the volumes of the display panel 100, the lower plate 200, the magnetic body group 300, and the housing element 400, the flexible display device is not completely folded flat in half, but folded in such a way that a folded area FR is created which has a predetermined surface that is folded to form a C-shaped curve, as shown in Fig. 4 shown.

[0045] Here is the top of the in the Fig. 1, Fig. 2 to Fig. The top of the display panel 100 shown in Figure 3 is the upper surface of the flexible display device, which is exposed to the outside and is a display surface. The underside of a base panel 400a of the housing element 400 is the underside of the flexible display device through which the housing element 400 or another system cover (not shown) is observed. In other words, the top of the display panel 100 is a surface on which an image is displayed by the display panel 100. The underside is the surface of the display panel 100 that is opposite the top of the display panel 100.

[0046] The flexible display device is shown as being formed in an approximately rectangular shape. However, this is only for illustrative purposes, and the present invention is not limited to this. The four corners of the flexible display device can be rounded. The flexible display device can be formed in a more polygonal shape than in a rectangular or circular shape. The shapes of the display panel 100, the lower plate 200, the magnetic body group 300, and the housing element 400 can be determined in accordance with the desired shape of the flexible display device. The display panel 100, the lower plate 200, the magnetic body group 300, and the base panel 400a of the housing element 400 can be approximately the same size.

[0047] Here, “folding area FR” refers to an area that is designed to be foldable, and “non-folding area UFR” refers to an area that is designed to be non-foldable. The shapes of the lower plate 200, the magnetic body group 300, and the housing element 400 can vary according to the design type of the folding area FR and the non-folding area UFR of the flexible display device according to the present invention. The first embodiment shown is a foldable display in which the folding area FR is located at the central sections of the display panel 100 and the lower plate 200.

[0048] The display panel 100 is a panel that displays an image independently. To maintain flexibility, a flexible base substrate 112 can be used (see Fig. 6), on which a thin-film transistor arrangement 1100 (see Fig. 12) is arranged as a flexible plastic film or an organic substrate. The flexible base substrate 112 has a thickness in the range of approximately 3 µm to approximately 100 µm. The total thickness of the display panel 100, including the arrangement configuration formed on the flexible base substrate 112, is in the range of approximately 5 µm to approximately 300 µm, with each section of the display panel 100 being able to be folded or bent. However, the folding area FR can be defined as a specific area in accordance with conditions required for the finished flexible display device. The folding area FR of each of the components (the bottom plate 200, the magnetic body group 300, and the housing element 400), with the exception of the display panel 100, can be specified to have an individual configuration in accordance with the respective required specification of the components.To ensure sufficient flexibility and prevent damage to the arrangement during the folding process, the display panel 100 may, if necessary, also have a flexible base substrate 112, the arrangement or surface structure of which in the folding area FR differs from that in the non-folding area UFR.

[0049] The lower plate 200 has a folding area FR and a non-folding area UFR. The lower plate 200 is configured as a stainless steel (SUS, also referred to as "stainless steel") plate. The lower plate 200 is positioned such that one surface of it, i.e., the top surface of the lower plate 200, faces the underside of the display panel 100. That is, the display panel 100 and the lower plate 200 overlap, with surfaces of them in contact with each other, so that the display panel 100 and the lower plate 200 are actuated together during the folding or unfolding process. As shown in Fig. As shown in Figure 5, an adhesive layer 150 can be provided between the display panel 100 and the lower plate 200. Alternatively, the adhesive layer 150 can be omitted. In the case where the adhesive layer 150 is not provided, the display panel 100 and the lower plate 200 can be in contact with each other without a gap between them, or there can be an air gap of 10 µm or less between them.

[0050] The reason for constructing the lower plate 200 using stainless steel (SUS) is to ensure sufficient stiffness and flexibility despite its small thickness. Stainless steel is a material whose modulus is greater than that of an insulating film provided in the flexible base substrate 112 and the arrangement configuration contained in the display panel 100. In general, a modulus is a coefficient that expresses stiffness. A smaller modulus indicates greater elasticity, and a larger modulus indicates less elasticity and greater stiffness, i.e., a property of maintaining an original state. A Young's modulus can be measured, and the measured value can be used.

[0051] The lower plate 200 has several slots 202 (see Fig. 7), which are formed in the folding area FR, thereby reducing the density (or specific gravity) of the folding area FR below that of the non-folding area UFR. The reason for forming the slots in the folding area FR of the lower plate 200 is as follows. The folding area FR is repeatedly subjected to stress during the folding process. If the folding area FR is formed such that it has a mass ratio (or specific gravity) equal to that of the non-folding area UFR, it can take a long time for the folding area FR to return to its original state after folding. The aforementioned slots are formed to allow the folding area FR to quickly return to its original state after folding.This means that, to ensure sufficient stiffness of the lower plate 200 and rapid restoration to its original state after folding, the slots 202 in the folded area FR of the lower plate 200 are designed such that the mass ratio of the folded area FR is smaller than that of the unfolded area UFR. The slots 202 can extend through the entire thickness of the folded area FR of the lower plate 200, or they can extend to a predetermined depth within the entire thickness of the folded area FR of the lower plate 200. The slots can be arranged at regular intervals throughout the folded area FR. The slots can be arranged such that their density gradually increases or decreases from the center of the folded area FR towards the edge.

[0052] In any case, the slots 202 are located in the folding area FR of the lower plate 200. The lower plate 200 is not divided into several pieces by the slots, but is configured as a single plate corresponding to the display panel 100.

[0053] Metal films 211 and 213 (see the Fig. 8A to 8D) are provided on the surfaces of the lower plate 200 to be brought into contact with the display panel 100, which is arranged on the lower plate 200, and the magnetic body group 300, which is arranged under the lower plate 200.

[0054] The magnetic body group 300 can comprise a first magnetic body 300a, corresponding to the non-folding region UFR, and a second magnetic body 300b, corresponding to the folding region FR. The first and second magnetic bodies 300a and 300b can be brought into contact with another surface of the lower plate 200, i.e., the underside of the lower plate 200, by magnetic attraction. In other words, the underside of the lower plate 200 is opposite the top surface of the lower plate 200. The first magnetic body 300a and the second magnetic body 300b can be formed to have the same thickness, without any difference in height between them. Each of the first magnetic body 300a and the second magnetic body 300b can be formed to have a thickness in the range of approximately 0.3 mm to approximately 5 mm to provide sufficient rigidity and to stably support the lower plate 200.The magnetic body group 300 is configured such that the first magnetic body 300a is arranged in each of the non-folding areas UFR, which are located on both sides of the folding area FR, and has a single-plate configuration, and such that the second magnetic body 300b is arranged in the folding area FR and is divided into more than one piece.

[0055] The second magnetic body 300b, provided in the folding area FR of the magnetic body group 300, can be divided in accordance with the split configuration of the housing element 400, which is arranged below the magnetic body group 300. Each of the magnetic body group 300 and the housing element 400 can be formed to have a thickness and stiffness greater than the thickness and stiffness of the display panel 100 or the lower plate 200, in order to maintain their shapes. The reason for forming the housing element 400 and the second magnetic body 300b in such a way that they have a split configuration in the folding area FR is as follows. Unlike the lower plate 200, the second magnetic body 300b is not flexible, and thus, as in Fig. As shown in Figure 4, the second magnetic body 300b remains flat even during the folding process. Therefore, the second magnetic body 300b is divided into several parts, minimizing the contact area between the second magnetic body 300b and the lower plate 200 when the folding area FR is folded with a large curvature. As shown in Figures 3 and 4, each of the first and second magnetic bodies 300a and 300b, forming the magnetic body group 300, has a flat top and bottom surface, respectively, facing the lower plate 200 and the housing element 400. In this state, the first and second magnetic bodies 300a and 300b are held in surface contact with the lower plate 200 and the housing element 400.

[0056] Segments 410 of the housing element 400, located in the folding area FR, are formed separately from one another. Therefore, even if the housing element 400 is folded such that the radius of curvature R on a section of it relatively far from the flexible lower plate 200 and the radius of curvature R on a section of it relatively close to the flexible lower plate are different from each other, the segments 410 can be arranged such that their upper surfaces are close together and their lower surfaces are spaced apart. That is, during the folding process, the segments 410 of the housing element 400 can withstand any change in the shape of the device.

[0057] When the device is switched from the folded state to the unfolded state, as in Fig. As shown in Figure 3, the segments 410 can be returned to their original state in which the distance between the tops and the distance between the bottoms of the adjacent segments 410 are equal.

[0058] In the flexible display device according to the first embodiment of the present invention, the folding area FR of the housing element 400 is divided into five segments 410. Each of the segments 410 can be formed in a single linear configuration extending continuously along the folding axis direction. Although the drawings show that the folding area FR of the housing element 400 is divided into five segments 410, the present invention is not limited to this. The number of segments can vary depending on the curvature formed during the folding process. When the display panel 100 is folded, a predetermined space is formed between the upper and lower sections of the folded display panel 100, which are opposite each other. The smaller this space, the more precisely the folding process is realized.For this purpose, the number of segments can be further increased. The reason for providing several segments 410 (e.g., five segments) in the folding area FR of the housing component 400 is to enable the folding area FR of the housing component 400, which has greater stiffness than other components, to fold in a smooth curve. As in . Fig. As shown in Figure 4, the five segments 410 are connected to each other using springs 412 that expand during the folding process. Each of the segments 410 has a body 415 that has holes 411 in its left and right sections. The section of the body 415 in which the hole 411 is formed can have a protruding configuration (a convex section 414) or a recessed configuration (a concave section 413). In the unfolded state, as shown in Figure 4, the five segments 410 are connected to each other by ... Fig. Figure 3 shows the adjacent segments 410 arranged such that the hole 411 formed in the concave section 413 of one segment 410 and the hole 411 formed in the convex section 414 of the other overlap, and such that the spring 412 inserted into the holes 411 is in its most compressed state. When a tensile force is applied to the segments 410 during the folding process, as shown in Figure 3, the spring 412 is compressed. Fig. As shown in Figure 4, the spring 412 expands, and the concave section 413 of one of the adjacent segments 410 and the convex section 414 of the other are therefore separated from each other. Among the segments 410, the segment 410 located in the middle (the center of the C-shaped configuration in Figure 4) has a convex section 413. Fig. 4) concave sections 413 formed on both sides of the body 415, and each of the remaining segments 410 has a concave section 413 formed on one side of the body 415 and a convex section 414 formed on the opposite side of the body 415. By this configuration, the springs 412 are coupled to the segments 410 to be symmetrical in the transverse direction based on the center of the folding area FR. However, the present invention is not limited to this. All segments 410 can have the same configuration, such that the concave section 413 is formed on one side of the body and the convex section 414 is formed on the opposite side of the body.This means that the positions of the concave section 413 and the convex section 414, which are formed symmetrically in each of the segments 410, correspond to the positions of the concave section and the convex section in the other segment. Therefore, all segments 410 have the same coupling structure between the springs 412 and the holes 411.

[0059] In the unfolded state, the concave section 413 of one of the adjacent segments 410 and the convex section 414 of the other overlap, and the spring 412 is in its most compressed state. In the folded state, the adjacent segments 410 are separated from each other, and the spring 412 expands out of the hole 411 formed in the concave section 413.

[0060] The surface of body 415 of each of the segments 410 facing the lower plate 200 is flat. The second magnetic body 300b is arranged between the flat surface of each of the segments 410 and the lower plate 200. In the unfolded state, they adhere as shown in Fig. As shown in Figure 3, the second magnetic body 300b and the lower plate 200 are held together by the magnetic attraction exerted between the entire top surface of the second magnetic body 300b and the lower plate 200. In the folded state, the contact area between the second magnetic body 300b and the lower plate 200 varies depending on the degree to which the lower plate 200 is bent. In the folded state, the second magnetic body 300b and the lower plate 200 are held in at least line contact with each other in the direction of the fold axis (the direction that penetrates the drawing sheet).

[0061] As in Fig. As shown in Figure 4, in the folded state, the display panel 100, which is located in the innermost position, is folded such that an upper non-folding area UFR and a lower non-folding area UFR are opposite each other in the vertical direction, i.e., a direction perpendicular to the top of the display panel 100. At this point, the length by which the folding area FR expands from each of the lower plate 200, the magnetic body group 300, and the housing element 400, which are located further out than the display panel 100, gradually increases outwards during the folding process.

[0062] The lower plate 200, which is in surface contact with the display panel 100, has slots 202 (see Fig. 7), which are formed in the folding region FR, exhibit sufficient flexibility, allowing them to be folded integrally with the display panel 100. The magnetic body group 300 and the housing element 400, which have relatively high rigidity, can expand during the folding process due to the segments 410, which are divided in the folding region FR, and the springs 412 that connect the segments. The base panel 400a of the housing component 400, which is the non-folding region UFR of the housing component 400, includes a convex section 424 projecting towards the adjacent segment 410, a hole 422 formed in the convex section 424, and a spring 423 coupled to the hole 422 and the hole 411 formed in the adjacent segment 410. Through this configuration of the housing element 400, the base panel 400a and the segment 410 are connected to each other.

[0063] The second magnetic body 300b and the segments 410, which are divided within the folding area FR of the housing 400, extend along the folding axis direction. The second magnetic body 300b and each of the segments 410 of the housing element 400 can be held in contact with each other using an adhesive (not shown) and can therefore be operated together without separating from each other during folding or unfolding.

[0064] The magnetic body group 300 and the lower plate 200 adhere to each other by magnetic attraction. In the unfolded (flat) state, as shown in Fig. As shown in Figure 3, the magnetic body group 300 is in surface contact with the entire surface of the lower plate 200. In the folded (bent) state, the second magnetic body 300b, which is located in the folding area FR of the magnetic body group 300, is in contact with a smaller area of ​​the lower plate 200 in the direction of the folding axis than in the unfolded state. That is, the contact area between the second magnetic body 300b and the lower plate 200 gradually decreases as it transitions from the unfolded state to the folded state. This is because the lower plate 200 is relatively flexible, and the folding area FR is therefore bent into a circle during the folding process, whereas the second magnetic body 300b of the magnetic body group 300 has a strong property of retaining its original shape due to the properties of its material, even under the stress generated during the folding process.However, during the folding process, the second magnetic body 300b is not completely separated from the lower plate 200, but is held in line contact or partial surface contact with the lower plate 200 in the folding axis direction. Due to the at least line contact between the second magnetic body 300b and the lower plate 200, the contact between the magnetic body group 300 and the lower plate 200 is maintained during the folding process without additional adhesive.

[0065] The magnetic body group 300 has a flat surface, so that either the second magnetic body 300b in the folding region FR or the first magnetic body 300a in the non-folding region UFR has no protruding or recessed section. The second magnetic body 300b and the first magnetic body 300a have widths that differ from each other, but have the same length in the folding axis direction.

[0066] The housing element 400 accommodates the lower plate 200 and the magnet body group 300. As in Fig. As shown in Figure 1, the housing element 400 can have the base panel 400a and side panels 400b, each of which has a height equal to or greater than the sum of the height of the bottom plate 200 and the height of the magnetic body group 300, so that the bottom plate 200 and the magnetic body group 300 are invisible from the outside. The housing element 400 can further, as required, have top panels (not shown) extending inwards from the side panels 400b to cover the edges of the display panel 100. In this case, the top panels, arranged on the four sides of the display panel 100, can have different configurations. For example, each of the upper panels of the housing element 400, which are located on the left side, the right side and the top of the display panel 100, may have a narrower width than the upper panel of the housing element 400 that is located on the bottom of the display panel 100.In the case where a flexible printed circuit board 610 (see . Fig. 11) provided on the lower side of the display panel 100, the flexible circuit board can be shielded by the upper panel of the housing 400, which is located on the lower side of the display panel 100 and has a relatively large width.

[0067] Each of the segments 410, which are divided within the folding area FR of the housing element 400, can extend through the entire base panel, the side panels, and the top panels of the housing element 400. The segments 410 can be connected to one another and can be connected to the base panel 400a, which corresponds to the non-folding area of ​​the housing element 400, using the springs 412 and 423. The springs 412 and 423 can be made of a compressible material, such as rubber or the like.

[0068] In the flexible display device according to the present invention, the housing element 400, which has the segments 410, can be made of a material that has a higher stiffness than the material of the lower plate 200, such as plastic, metal, or surface-treated metal.

[0069] In some cases, the flexible display device according to the present invention may further comprise a system cover arranged outside the housing element 400 to improve the aesthetic appearance of the device or to accommodate additional components. In this case, the system cover may be made of a flexible material, unlike the housing element 400, so that it can be folded.

[0070] Fig. 5 is a cross-sectional view along line II-II' in Fig. 1 of a flexible display device according to another embodiment of the present invention.

[0071] As in Fig. As shown in section 5, the flexible display device according to the other embodiment differs from the one shown in the Fig. 4 and Fig. The device shown in Figure 5 consists in that an adhesive layer 150 is provided between the non-folding area UFR of the display panel 100 and the non-folding area UFR of the lower plate 200.

[0072] This means that in the flexible display device according to the other embodiment of the present invention, the display panel 100 and the lower plate 200 can be connected to each other by the adhesive layer 150, which is arranged between the surfaces of the display panel 100 and the surfaces of the lower plate 200 facing each other. In this case, the adhesive layer 150 can be provided not in the folding area FR, but only in the non-folding area UFR. This serves to prevent the adhesive layer from detaching from the folding area FR due to the deterioration of the bonding force between the two components, which is attributable to repeated folding and unfolding processes.

[0073] The magnetic body group 300 (300a and 300b) is in contact with the lower plate 200 due to magnetic attraction. In the unfolded state, the folded area FR of the magnetic body group 300 is in surface contact with the folded area FR of the lower plate 200 (see Fig. 3) In the folded state, the folding area FR of the magnetic body group 300 is at least in line contact with the folding area FR of the lower plate 200 (see Fig. 4) Therefore, the lower plate 200 and the magnetic body group 300 are held in contact with each other without an adhesive element being present between them.

[0074] The magnetic body group 300 can be arranged further inward than the edges of the display panel 100. Accordingly, if the magnetic body group 300, which is not used for display and has a greater thickness than the display panel 100 or the lower plate 200, is enclosed in the housing element 400, which has no upper panels, the magnetic body group 300 is shielded by the lower plate 200 or the display panel 100 arranged thereon. That is to say, in the flexible display device according to the present invention, the components arranged under the display panel 100 are invisible from the outside in every direction.

[0075] In either the flexible display device according to the first embodiment or the flexible display device according to another embodiment, when the display panel 100 is mounted on the housing element 400, the lower plate 200, which has a size equal to or similar to that of the display panel 100, is designed to face the surface of the display panel. Therefore, the lower plate 200, which has relatively high rigidity, also supports the display panel 100 to prevent it from sagging or bending, thus maintaining rigidity and consequently improving the reliability of the device despite repeated folding and unfolding operations. Furthermore, the section of the lower plate 200 corresponding to the folding area is designed to have a relatively low density, thereby reducing the stress exerted on the folding area.

[0076] Furthermore, when the display panel 100 is attached to the housing element 400, the lower plate 200 is provided beneath the display panel 100, and the magnetic body group 300 is provided beneath the lower plate to adhere to it by magnetic attraction. Therefore, no adhesive element is required between the housing element 400 and the display panel 100, whose materials have a significant difference in stiffness and physical properties. This prevents the adhesive element from detaching and prevents the display panel 100 from gradually separating from the housing element 400 due to repeated folding and unfolding operations.

[0077] The second magnetic bodies 300b, which are provided in the folding area FR of the magnetic body group 300, are arranged in accordance with the segments 410, which are distributed in the folding area FR of the housing element 400. By providing the second magnetic bodies 300b and the segments 410, which adhere to the second magnetic bodies 300b and have a housing function, it is possible to ensure the flexibility of the flexible display device in the folding area FR, which is folded with a large curvature.

[0078] The surfaces of the magnetic body assembly 300 and the surfaces of the lower plate 200, facing each other, are held flat and are therefore held in surface contact solely by magnetic attraction, without any additional protruding or fastening section. During the folding process, the second magnetic body 300b is not completely separated from the lower plate 200 in the folding area FR, but is held in line contact with the lower plate 200, or is partially in contact with it, by magnetic attraction. After returning from the folded to the unfolded state, the entire surface of the second magnetic body 300b is brought into contact with the lower plate 200 by magnetic attraction. Therefore, despite repeated folding and unfolding processes, the magnetic body assembly is not completely separated from the lower plate, and the components are thus stably housed within the casing element.

[0079] As described above, during the folding and unfolding processes, the display panel 100 and the lower plate 200 are operated together, and the lower plate 200 and the magnetic body assembly 300 adhere to each other by magnetic attraction. Therefore, no adhesive element is required between sections that are separated when the folding process is repeated. In particular, since no adhesive element is needed between the display panel 100 and the housing element 400, which have different material properties, it is possible to prevent damage to the display panel 100 caused by the adhesive element detaching during a post-processing step, and consequently to improve the production yield of the device.

[0080] A detailed description of the components of the flexible display device is given below.

[0081] Fig. Figure 6 is a cross-sectional view of the display panel 100 of the flexible display device.

[0082] As in Fig. As shown in Figure 6, a buffer layer 120 is formed on the flexible substrate (the flexible base substrate 112), and a thin-film transistor Tr is formed on the buffer layer 120. The buffer layer 120 can be omitted.

[0083] A semiconductor layer 122 is formed on the buffer layer 120. The semiconductor layer 122 can be made of an oxide semiconductor material or polycrystalline silicon.

[0084] In the case where the semiconductor layer 122 is formed from an oxide semiconductor material, a light-shielding pattern (not shown) may be formed beneath the semiconductor layer 122. The light-shielding pattern serves to prevent light from entering the semiconductor layer 122 and consequently prevents light degradation of the semiconductor layer 122. Alternatively, the semiconductor layer 122 may be formed from polycrystalline silicon. In this case, impurities may be doped onto both edges of the semiconductor layer 122.

[0085] A gate insulation film 124, formed from an insulating material, is formed on the semiconductor layer 122. The gate insulation film 124 can be formed from an inorganic insulating material, such as silicon oxide or silicon nitride.

[0086] A gate electrode 130, which is formed from a conductive material, such as metal, is formed on the gate insulation film 124 such that it is arranged according to the center of the semiconductor layer 122.

[0087] Although in Fig. Figure 6 shows that the gate insulation film 124 is formed over the entire surface of the flexible base substrate 112, and the gate insulation film 124 can be structured in the same shape as the gate electrode 130.

[0088] An interlayer insulating film 132, formed from an insulating material, is formed on the gate electrode 130. The interlayer insulating film 132 can be formed from an inorganic insulating material, such as silicon oxide or silicon nitride, or from an organic insulating material, such as benzocyclobutene or photoacrylic.

[0089] The interlayer insulating film 132 has a first and a second contact hole 134 and 136 through which both sides of the semiconductor layer 122 are exposed. The first and second contact holes 134 and 136 are arranged such that they are spaced apart from both sides of the gate electrode 130.

[0090] The first and second contact holes 134 and 136 are also formed in the gate insulation film 124. Alternatively, if the gate insulation film 124 is structured in the same way as the gate electrode 130, the first and second contact holes 134 and 136 can be formed only in the interlayer insulation film 132.

[0091] A source electrode 140 and a drain electrode 142, which are formed from a conductive material, such as metal, are formed on the interlayer insulating film 132.

[0092] The source electrode 140 and the drain electrode 142 are arranged such that they are spaced apart from each other at the base of the gate electrode 130. The source electrode 140 and the drain electrode 142 are in contact with both sides of the semiconductor layer 122 via the first and second contact holes 134 and 136, respectively.

[0093] The semiconductor layer 122, the gate electrode 130, the source electrode 140 and the drain electrode 142 form the thin-film transistor Tr, and the thin-film transistor Tr serves as a control element.

[0094] The thin-film transistor Tr can have a coplanar structure in which the gate electrode 130, the source electrode 140 and the drain electrode 142 are located on the semiconductor layer 120.

[0095] Alternatively, the thin-film transistor Tr can have an inverted staggered structure in which the gate electrode is located below the semiconductor layer and the source and drain electrodes are located on top of the semiconductor layer. In this case, the semiconductor layer can be made of amorphous silicon.

[0096] Although not shown, the gate wiring and data wiring cross over to define a pixel area. A switching element is also provided, connected to both the gate and data wiring. This switching element is connected to the thin-film transistor Tr, which acts as a driver.

[0097] A power line is formed parallel to the gate wiring or the data wiring, such that it is spaced apart from it. Furthermore, a storage capacitor may be provided to maintain a constant voltage at the gate electrode of the thin-film transistor Tr, which is a drive element, during a frame.

[0098] A protective layer 145, which has a drain contact hole 152 through which the drain electrode 142 of the thin-film transistor Tr is exposed, is formed such that it covers the thin-film transistor Tr. The thin-film transistor Tr is provided in each pixel area, and the thin-film transistors provided on the flexible base substrate 112 are collectively referred to as a thin-film transistor array.

[0099] A first electrode 160, connected to the drain electrode 142 of the thin-film transistor Tr via the drain contact hole 152, is formed on the protective layer 145 such that it is located in a corresponding pixel area. The first electrode 160 can be an anode, which may be formed from a conductive material with a relatively high work function. For example, the first electrode 160 can be formed from a transparent conductive material, such as indium tin oxide (ITO) or indium zinc oxide (IZO), or it can be configured as a multilayer electrode having at least one layer formed from the above transparent conductive material.

[0100] In the case where the display panel 100 is of an upward-emitting type, a reflective electrode or a reflective layer may also be formed beneath the first electrode 160. For example, the reflective electrode or the reflective layer may be made of an aluminum-palladium-copper (APC) alloy. In some cases, a transparent conductive material may also be included on the underside of the reflective electrode.

[0101] A bank layer 166, covering the edges of the first electrode 160, is formed on the protective layer 145. The bank layer 166 exposes the center of the first electrode 160 at the base of each pixel area.

[0102] An organic emission layer 162 is formed on the first electrode 160. The organic emission layer 162 can have a single-layer structure, comprising an emission material layer formed from an emitting material. To improve emission efficiency, the organic emission layer 162 can alternatively have a multi-layer structure in which a hole injection layer, a hole transport layer, an emission material layer, an electron transport layer, and an electron injection layer are stacked successively on the first electrode 160.

[0103] A second electrode 164 is formed on the flexible base substrate 112, on which the organic emission layer 162 described above has been formed. The second electrode 164 covers the entire area of ​​the display region. The second electrode 164 can be a cathode, which may be made of a conductive material with a relatively low work function. For example, the second electrode 164 can be made of an aluminum (Al), magnesium (Mg), or aluminum-magnesium (AlMg) alloy.

[0104] The first electrode 160, the organic emission layer 162, and the second electrode 164 form an organic light-emitting diode D. The organic light-emitting diode D is connected to the thin-film transistor Tr in each pixel region. The organic light-emitting diodes formed in all pixel regions are collectively referred to as an organic light-emitting diode array.

[0105] An encapsulation film 170 is formed on the second electrode 164 to prevent external moisture from penetrating the organic light-emitting diode D. The encapsulation film 170 can have a structure in which a first inorganic insulating layer 172, an organic insulating layer 174, and a second inorganic insulating layer 176 are stacked on top of each other. However, the present invention is not limited to this. Alternatively, the encapsulation film 170 can have a structure in which inorganic insulating layers and organic insulating layers are stacked alternately, with the inorganic insulating layer located in the outermost position.

[0106] A touch electrode arrangement comprising a first touch electrode 181 and a second touch electrode 182, which intersect to detect touch, can further be provided on the encapsulation film 170. The bridge wiring 181a is provided on the second inorganic insulating layer 176, which is located at the outermost position. A touch insulation film 183 is provided on the bridge wiring 181a, and a first touch pattern 181b and the second touch electrode 182 are arranged on the touch insulation film 183 such that they are spaced apart from each other. The first touch pattern 181b is electrically connected to the bridge wiring 181a by a contact hole formed in the touch insulation film 183, thereby forming the first touch electrode 181. Only a portion of the second touch electrode 182 is shown in the drawings.The second touch electrode 182 is located on a section of the touch insulation film 183 on which the first touch pattern 181b is not arranged, and a mutual capacitance Cm is generated between the first touch pattern 181b and the second touch electrode 182, which are spaced apart from each other.

[0107] The presence or absence of contact can be detected by sensing a change in mutual capacitance Cm in response to contact.

[0108] The illustrated touch electrode arrangement is for illustrative purposes only, and the present invention is not limited to it. As shown, the touch electrode arrangement can be formed directly on the encapsulation film 170. Alternatively, an additional substrate or an insulating film can be provided between the encapsulation film and the touch electrode arrangement, or the touch electrode arrangement can be provided within a cover film. In some cases, the touch electrode arrangement can be omitted, or the encapsulation film 170 can be located on the upper side of the display panel 100.

[0109] A polarizing plate (not shown) for reducing the reflection of external light can be attached to the contact electrode assembly. For example, the polarizing plate can be circular. A cover layer, such as a cover window or the like, can also be provided to protect the top of the contact electrode assembly.

[0110] The unexplained reference numeral 1100 denotes an arrangement structure comprising the thin-film transistor arrangement formed on the flexible base substrate 112, the organic light-emitting diode arrangement connected to the respective thin-film transistors Tr, the encapsulation layer 170 covering the above components, and the contact electrode arrangement 181, 182 and 183.

[0111] The display panel described above is an example of an organic light-emitting display panel. Any other type of display panel can be used, as long as it is flexible. For example, the organic light-emitting display panel described above can be replaced by a flexible liquid crystal panel, a quantum dot display panel, or an electrophoretic display panel.

[0112] Fig. Figure 7 is a top view of the lower plate of the flexible display device, and the Fig. 8A to 8D are cross-sectional views along line III-III' in Fig. 7.

[0113] The lower plate 200 of the flexible display device according to the first embodiment of the present invention is formed from a steel alloy material having a certain stiffness, such as stainless steel (SUS), which can adhere to the magnetic body group 300, formed from a magnetic steel material, by magnetic attraction and which comprises 50% or less of alloying elements other than steel and 7 to 32% chromium (Cr). In addition to steel and chromium, the material of the lower plate 200 may further comprise a metal, such as nickel, and a non-metallic material, such as silicon (Si).

[0114] Stainless steel is generally classified into austenitic, ferritic, and martensitic series. An austenitic series can be excluded from these to increase the force with which the lower plate 200 adheres to the magnetic bodies.

[0115] As in Fig. As shown in Figure 7, the lower plate 200 has the slots 202 formed in the folding region FR. The slots 202 have a first pattern 202a formed in a (2n-1)th row, and a pair of second patterns 202b formed in a (2n)th row (here n is a positive integer).

[0116] Although in Fig. Figure 7 shows that the folding area FR is located in the center of the lower plate 200; however, the position of the folding area FR is not limited to this. Alternatively, two or more folding areas can be defined.

[0117] Each of the first and second patterns 202a and 202b can have a rectangular shape. The distance between the pair of second patterns 202b formed in the (2n)th row can be determined depending on the dimension of the first pattern 202a formed in the (2n-1)th row.

[0118] Both ends of the first pattern 202a can be arranged inwards from both sides of the lower plate 200 in the folding area FR, and one end of each of the second patterns 202b can be located on either side of the second pattern 202a of the lower plate 200 in the folding area FR.

[0119] This means that each of the two sides of the lower plate 200 has a discontinuity formed in the (2n)th row. Therefore, the folding region FR of the lower plate 200 is defined by the region between the first pattern 202a and the second pattern 202b and the region between the pair of second patterns 202b, thus giving the folding region FR the function of a spring.

[0120] It is in Fig. Figure 7 shows that a single first pattern 202a is formed in the odd-numbered ((2n-1)th) row and a pair of second patterns 202b are formed in the even-numbered ((2n)th) row. However, two or more first patterns 202a can be formed, and three or more second patterns 202b can be formed.

[0121] Each of the first and second patterns 202a and 202b extends in the row direction. That is, the long axis of each of the first and second patterns 202a and 202b can be parallel to the row direction.

[0122] A first distance D1 between the pair of second patterns 202b can be equal to or less than a first length L1 of each of the second patterns 202b. It is desirable that the first distance D1 be less than the first length L1.

[0123] When the flexible display device is folded and unfolded, the folding area FR, in which the slots 202 are formed, acts as a spring and increases the elastic restoring energy of the lower plate 200. Therefore, if the stress exerted on the flexible display device during the folding process is eliminated, the time required to return to its original state can be reduced.

[0124] The shape of the slots 202 is not based on the one in Fig. The rectangular shape shown in Figure 7 is limited. The first and second patterns forming the slots 202 can have any other polygonal shape, a polygonal shape with rounded corners, or an elliptical shape extending along the fold axis direction.

[0125] As in Fig. As shown in Figure 7, the slots 202 can be formed such that the first patterns 202a and the second patterns 202b are arranged alternately at regular intervals throughout the entire area of ​​the folding region FR. Alternatively, a group of patterns can be arranged more densely or more sparsely with an identical shape from the center of the folding region FR to the edge of the folding region FR. Alternatively, a group of patterns can be arranged randomly to distinguish the folding region FR from the non-folding region UFR. Each of the first and second patterns 202a and 202b can be formed such that its longitudinal direction is parallel to the folding axis direction. That is, the slots 202 can be formed such that they extend along the folding axis direction in the top view.

[0126] As in Fig. As shown in Figure 7, due to the slots 202 formed in the folding area FR of the lower plate 200, it is possible to prevent a break in the folding area FR, which is attributable to repeated folding and unfolding operations, and to reduce the amount of stress exerted on the folding area FR during the folding process.

[0127] The lower plate 200 is located beneath the display panel 100 to support it. The lower plate 200 has a higher stiffness than the flexible base substrate 112. This means that the lower plate 200 can have a higher modulus of elasticity than the flexible base substrate 112.

[0128] Since the lower plate 200 is made of a material with relatively high stiffness, such as stainless steel (SUS), it can have a high restoring force and can be reduced in thickness.

[0129] This means that if the lower plate 200 is made of a material with relatively high stiffness, such as SUS, its stiffness can be maintained at the desired level despite a reduction in thickness. This ensures stable support for the display panel 100. Furthermore, it is possible to reduce the plastic deformation of the lower plate 200 that results from the reduction in thickness.

[0130] However, the elastic deformation range of the lower plate 200, which is made of a material with relatively high stiffness and relatively low thickness, is rather narrow. Therefore, it is very difficult for such a lower plate to return to its original state after deformation. That is, after the folding process is complete, the lower plate 200 remains in a folded state for a long time without being unfolded.

[0131] In the flexible display device according to the present invention, the elastic deformation range of the lower plate 200 increases due to one or more slots 202 formed in the folding area FR of the lower plate 200. Furthermore, due to the slots 202, the folding area FR of the lower plate 200 acts as a spring, and the restoring force of the lower plate 200 is increased. Therefore, it is possible to solve a problem where the time required to restore the lower plate 200 increases due to a reduction in thickness. The slots 202 formed in the folding area FR of the lower plate 200 can be formed to a depth equal to the thickness of the lower plate, or they can be formed to a depth less than the thickness of the non-folding area UFR of the lower plate 200.Alternatively, the slots 202 can be formed such that the first patterns are formed over the entire thickness of the lower plate 200 and that the second patterns are formed with a depth less than the thickness of the lower plate 200.

[0132] As described above, since the lower plate 200 is made of a material with high stiffness, its restoring force is increased, and its elastic deformation range increases due to the slots 202. Therefore, despite a reduction in the thickness of the lower plate 200 to, for example, 2 mm or less, the flexible display device has improved reliability with respect to the folding process and can be easily returned to its original state.

[0133] As in the Fig. As shown in Figures 8A to 8D, a first step compensation layer 211 and a second step compensation layer 213 can each be formed on the top and bottom surfaces of the lower plate 200, respectively, to prevent the formation of steps between the slots 202 and to protect the lower plate 200. Each of the first and second step compensation layers 211 and 213 can be configured as a metal film made of stainless steel (SUS), which is the main component of a body 200a of the lower plate 200. In this case, the second step compensation layer 213, located on the bottom surface of the lower plate 200, can be in direct contact with the magnetic body group 300.

[0134] Alternatively, the first and second stage compensation layers 211 and 213 can be made of a material that has a lower stiffness than the material of the lower plate 200. For example, each or one of the first and second stage compensation layers 211 and 213 can be made of any material selected from polyurethane (PU), thermoplastic polyurethane (TPU), polyacrylate, rubber, and silicon (Si).

[0135] In this case, the first and second step compensation layers 211 and 213 serve to protect the slots 202 by covering them and eliminating steps. Furthermore, the first and second step compensation layers 211 and 213 can prevent the occurrence of a faulty display that may be caused by the slots 202.

[0136] Only one of the first and second step compensation layers 211 and 213 can be formed, and can be selectively provided only on the folding area FR.

[0137] In some cases, the first and second step compensation layers 211 and 213 can also be arranged in the slots 202 formed in the folding area FR. In this case, the step compensation layers arranged in the slots 202 are made of a material that has a lower stiffness than the material of the lower plate 200, i.e., SUS, and the reliability of the step compensation layers can therefore be maintained despite repeated folding and unfolding operations of the folding area FR.

[0138] As in Fig. As shown in Figure 8A, the slots 202 can be formed to a depth corresponding to a partial thickness P1 of the body 200a. As shown in Fig. As shown in Figure 8B, the slots 202 can be formed over the entire thickness P2 of the body 200a. As shown in Fig. As shown in Figure 8C, slots 202 extending from the top of the body 200a to a depth corresponding to the partial thickness P1 of the body 200a and slots 202 extending from the bottom of the body 200a to a depth corresponding to the partial thickness P3 of the body 200a can be arranged alternately. Fig. As shown in Figure 8D, slots 202 formed over the entire thickness P2 of the body 200a and slots 202 extending from the top of the body 200a to a depth corresponding to the partial thickness P1 of the body 200a can be arranged alternately.

[0139] As described above, according to the flexible display device of the present invention, its overall thickness can be reduced due to the high stiffness of the lower plate 200. Additionally, the restoring force of the lower plate 200 can be increased by means of the slots 202, which allows the folding area FR of the lower plate 200 to function like a spring. That is, a lower plate with a small thickness and a high restoring force can be provided.

[0140] The Fig. Figures 9A to 9C are top views showing different embodiments of the magnetic bodies that are brought into contact with the lower plate in the flexible display device according to the present invention. Fig. Figures 9A to 9C show the surfaces of the lower plate 200 and the magnetic body group 300 as seen from below. Since the lower plate 200 has a surface area larger than that of the magnetic body group 300, the edge sections of the lower plate 200 can be seen when viewed from below. An adhesive element (not shown) can be provided on the underside of the magnetic body group 300, and thus the housing element 400, which is located under the magnetic body group 300 on the basis of Fig. 1 is arranged, connected to the magnetic body group 300.

[0141] In the flexible display device according to the present invention, the magnetic body group 300 is formed from magnetic steel, which is an alloy comprising at least two metals selected from the group consisting of carbon, chromium, tungsten, molybdenum, cobalt, aluminum, steel, vanadium (V), manganese, titanium (Ti), and combinations thereof. This material has a residual flux density (Br) of 5000 gauss or more, and thus the magnetic body group 300 functions as a type of permanent magnet. Furthermore, in the flexible display device according to the present invention, the magnetic body group 300 comprises the first magnetic body 300a, which is formed in a plate configuration in the non-folding region UFR, and the second magnetic body 300b, which is divided into several pieces in the folding region FR to correspond to the divided configuration of the housing element 400. Each second magnetic body 300b has a small width and extends in the folding axis direction.

[0142] The second bodies 300b, which are in the Fig. 9A to 9C, as shown, have the same configuration relative to each other in the folding region FR, but the first bodies 300a, which are in the Fig. Figures 9A to 9C, shown here, have different arrangements and configurations in the non-folding area UFR.

[0143] Referring to Fig. 9A In the non-folding areas UFR, first magnetic bodies 300a are provided, located above and below the folding area FR. Each of the first magnetic bodies 300a is formed in the form of a large plate with an area corresponding to one of the respective non-folding areas. Several second magnetic bodies 300b are provided in the folding area FR to correspond to the segments divided in the housing element 400.

[0144] The first magnetic body 300a, located in the non-folding region UFR, is held in surface contact with the lower plate 200 by magnetic attraction, regardless of whether the flexible display device is being folded or unfolded. Since the second magnetic body 300b, located in the folding region FR, is made of magnetic steel with a higher stiffness than the material of the folding region FR of the lower plate 200, the second magnetic body 300b is held in surface contact with the lower plate 200 in the unfolded state, but is also held in partial contact with the lower plate 200, which is bent with a large curvature in the folded state. In the folded state, the second magnetic body 300b is held in at least line contact with the folding region FR of the lower plate 200 in the direction of the folding axis, without being completely separated from the lower plate 200.Therefore, when returning from the folded state to the unfolded state, the entire surface area of ​​the second magnetic body 300b is quickly brought into contact with the lower plate 200 without any gap in between.

[0145] Referring to the Fig. 9A is the first magnetic body 300a spaced from the edge of the lower plate 200 by a first distance a. As described above, this serves to make the magnetic body group 300 invisible in any direction from the display surface of the display panel 100 (see Fig. 1) In the same way, the second magnetic body 300b is also spaced from the edge of the lower plate 200 by the first distance a. The second magnetic bodies 300b provided in the folding area FR are spaced apart from each other by a second distance b. However, this is only for illustrative purposes, and the arrangement of the second magnetic bodies 300b can vary according to the configuration of the folding area FR of the housing element 400. Depending on the degree to which the folding area FR is bent, the distance between the second magnetic bodies 300b can increase, or the width of each of the second magnetic bodies 300b can decrease.

[0146] One of the second magnetic bodies 300b, located at the outermost position in the folding region FR, can be spaced apart from the first magnetic body 300a, which is provided in the non-folding region UFR, by a third distance c. The value of the third distance c and the width of the first magnetic body 300a can be, as shown in the Fig. 9B and Fig. Shown as 9C, they vary.

[0147] The reason for placing the first and second magnetic bodies 300a and 300b in the non-folding area UFR and the folding area FR of the magnetic body group 300 is to ensure that at least part of the magnetic body group 300 remains in contact with the lower plate 200 despite repeated folding and unfolding operations, without being separated from it. Furthermore, if an adhesive element is provided on the underside of the magnetic body group 300 and the housing element 400 is connected to the magnetic body group 300 by this adhesive element, the housing element 400 and the magnetic body group 300 are actuated together during the folding process. Therefore, during the folding process, at least part of the magnetic body group 300 remains in contact with the lower plate 200 instead of being completely separated from it, thus eliminating the need for an adhesive element between the lower plate 200 and the magnetic body group 300.

[0148] As in the Fig. 9B and Fig. As shown in Figure 9C, the area occupied by the first magnetic body 300a in the non-folding area UFR of the magnetic body group 300 can constitute more than 10% of the total area of ​​the non-folding area UFR of the lower plate 200. The reason for this is to ensure that the magnetic attraction between the first magnetic body 300a and the non-folding area UFR of the lower plate 200 is equal to or greater than the magnetic attraction between the second magnetic body 300b and the folding area FR of the lower plate 200 in the unfolded state. As shown in Fig. As shown in Figure 9A, in the case where the first magnetic body 300a is provided in the entire non-folding region UFR, there is no step between the non-folding region UFR and the folding region FR. As shown in the Fig. 9B and Fig. As shown in Figure 9C, even if the first magnetic body 300a is selectively provided only on a section of the non-folding area UFR, the magnetic attraction force with which the magnetic body group 300 is held in surface contact with the underside of the lower plate 200 can be sufficiently ensured.

[0149] The Fig. 10A and Fig. Figures 10B are perspective views showing the unfolded state and the folded state of the folding area of ​​the housing element in the flexible display device according to the present invention.

[0150] In the flexible display device according to another embodiment of the present invention, the folding area FR of the housing element can have 400 joints and gears instead of the springs described above with reference to the Fig. 1, Fig. 2, Fig. 3 to Fig. 4 described embodiments are provided.

[0151] Referring to the Fig. 10A and Fig. 10B, the folding area 4100 of the flexible display device comprises a first unit joint 2410, a second unit joint 2420 having the same configuration as the first unit joint 2410 and interlocking with one side of the first unit joint 2410 to move relative to it, and a third unit joint 2430 interlocking with one side of the second unit joint 2420 to move relative to it and arranged opposite to the first unit joint 2410 on the base of the second unit joint 2420, and connecting elements 2470 connecting the unit joints 2410 to 2460 to each other, arranged adjacent to each other.

[0152] In addition, a fourth to sixth unit joint 2440 to 2460 are provided, which interlock with each other in the same way as the first to third unit joint 2410 to 2430.

[0153] As in Fig. As shown in Figure 10B, the folding area 4100 can be folded (bent) around the folding axis. In the folded state, the folding area 4100 is folded approximately in a C-shaped configuration, such that the upper surfaces of the first to sixth unit hinges 2410 to 2460 are oriented inwards, and their lower surfaces are oriented outwards.

[0154] The folding area 4100 of the housing element is formed as an arrangement created by the engagement of the first to sixth unit hinges 2410 to 2460. That is, the first to sixth unit hinges 2410 to 2460 are arranged successively along the side of the folding area of ​​the housing element 400 (see Fig. 1) and extend in the direction of the folding axis. Each of the second magnetic bodies 300b can be in contact with the top surface of a respective first to sixth unit hinge 2410 to 2460 in the direction of the folding axis.

[0155] The first unit joint 2410 has an elongated elliptical shape when viewed from the side. The first unit joint 2410 has a first pivot shaft and a second pivot shaft, each arranged on two opposite side sections of the first unit joint 2410. The first unit joint 2410 further has first toothed sections 2411 formed on the outer circumferential surface adjacent to the first pivot shaft, and second toothed sections 2412 formed on the outer circumferential surface adjacent to the second pivot shaft.

[0156] Each of the first teeth 2411 and the second teeth 2412 can be formed on the entire surface or on a section of the corresponding outer circumferential surface. The first teeth 2421 of the second unit joint 2420 mesh with the second teeth 2412 of the first unit joint 2410, and the first teeth 2431 of the third unit joint 2430 mesh with the second teeth 2422 of the second unit joint 2420. In this way, the first teeth 2411, 2421, and 2431 and the second teeth 2412, 2422, and 2432 of the unit joints mesh with each other.

[0157] The first to sixth unit joints 2410 to 2460 have the same configuration.

[0158] The first to sixth unit joints 2410 to 2460 are described assuming that the first pivot shaft and the second pivot shaft are arranged within one side and the opposite side of each of the unit joints 2410 to 2460.

[0159] The first unit joint 2410 and the second unit joint 2420 are connected to each other such that the second pivot shaft of the first unit joint 2410 and the first pivot shaft of the second unit joint 2420 are connected to each other by the connecting element 2470. The second pivot shaft of the second unit joint 2420 and the first pivot shaft of the third unit joint 2430 are connected to each other by the connecting element 2470. In this way, the unit joints 2410 to 2460, which are arranged one after the other, are connected to each other by the connecting elements 2470 so that they rotate relative to each other and are rotated sequentially during the folding and unfolding processes.

[0160] Since the first pivot shaft is attached to one side of the first unit joint 2410, the second unit joint 2420 and the subsequent unit joints 2430 to 2460 are arranged to perform a relative rotation about the second pivot shaft of the first unit joint 2410.

[0161] When the rotation of the second unit joint 2420 relative to the first unit joint 2410 is complete, the third unit joint 2430 performs a relative rotation about the second pivot shaft of the second unit joint 2420. In this way, all interconnected unit joints perform a relative rotation at regular angles.

[0162] After the relative rotation of the second to sixth unit joints 2420 and 2460 has been carried out successively, as in Fig. As shown in Figure 10B, the folding area 4100 is folded approximately into a C-shaped configuration.

[0163] The first teeth 2421 of the second unit joint 2420 mesh with the second teeth 2412 of the first unit joint 2410, and only the second unit joint 2420 performs a relative rotation. The rotation of the second unit joint 2420 relative to the first unit joint 2410 does not interrupt the rotation of the other unit joints. That is, each of the unit joints can perform a relative rotation independently. Since the unit joints rotate around two or more multiple shafts, the unit joints can perform a relative rotation sequentially or stepwise. If the gears are configured to rotate around a single shaft, when one of the gears rotates, all the other gears rotate together simultaneously, preventing the unit joints from rotating sequentially or stepwise.

[0164] The first unit joint 2410 has a rotation limiting element 2415 projecting from one side of its underside and a limiting recess 2416 formed on the opposite side of its underside, into which a rotation limiting element of the second unit joint 2420 is inserted. When the folding area 4100 of the housing element is folded, the rotation limiting element 2415 of each unit joint is inserted into the limiting recess 2416 formed in the unit joint adjacent to it, thereby limiting the rotation of the unit joints. This insertion of the rotation limiting element 2415 into the limiting recess 2416 determines the angle at which each unit joint performs a relative rotation.For example, the angle at which each of the unit joints performs a relative rotation can be determined by the degree by which the rotation limiting element 2415 projects, or by the degree to which the limiting recess 2416 is depressed. Due to the insertion of the rotation limiting element 2415 into the limiting recess 2416, the folding area 4100 of the housing element can be folded with a constant curvature R, and the stiffness of the folding area can be ensured.

[0165] The folding area of ​​the housing element described above is for illustrative purposes only. The length of each of the unit joints can be increased in the direction of the folding axis, or the gears of the unit joints can be changed in shape or replaced by other rotating elements.

[0166] Fig. Figure 11 is a cross-sectional view showing an exemplary electronic device to which the flexible display device according to the present invention is applied.

[0167] As in Fig. Figure 11 shows an exemplary electronic device implemented by the flexible display device according to the present invention, comprising a display panel 100 having a flexible base substrate 112 and an arrangement structure 1100 arranged on the flexible base substrate 112, the arrangement structure 1100 comprising the aforementioned thin-film transistor arrangement, the organic light-emitting diode arrangement, the encapsulation film, and the touch electrode arrangement, a flexible printed circuit board 610 connected to a contact section (not shown) provided on one side of the flexible base substrate 112, plates 540 and 550 provided under the first magnetic bodies 300a in the non-folding area UFR, a printed circuit board 650 provided under the plates 540 and 550 to be connected to the flexible printed circuit board 610, and a battery 700 connected to the Circuit board 650 is connected,to supply them with electrical energy, and a housing structure 800 that accommodates the components 150, 200 and 300, which are arranged under the display panel 100.

[0168] To shield the flexible printed circuit board 610, the housing structure 800 can be designed such that the upper panel extending from the side on which the flexible printed circuit board 610 is located is longer than the upper panels extending from the other sides. This is similar to the housing element 400 described above, which is located in the Fig. 1, Fig. 2, Fig. 3 to Fig. As shown in Figure 4, the folding area FR of the housing structure 800 can be divided into several segments which are connected to each other by springs in order to realize a kind of joint movement due to expansion and compression of the springs during the folding and unfolding processes.

[0169] In some cases, as in Fig. Figure 5 shows that a driver circuit may be embedded on the top side of the display panel 100 in an integrated circuit (IC) configuration. In this case, the driver circuit may be connected to the printed circuit board 650 via a connector (not shown).

[0170] The illustrated electronic device further comprises a lower plate 200, configured as a single plate without gaps, and a magnetic body group 300, comprising a first magnetic body 300a located in the non-folding region UFR and a second magnetic body 300b located in the folding region FR. To improve reliability despite repeated folding and unfolding operations as described above, the lower plate 200 may have slots 202 (see Figure 2). Fig. 7) An adhesive layer 150 for connecting the display panel 100 and the lower plate 200 can only be provided in the non-folding area UFR. This serves to prevent the adhesive layer 150 from detaching from the folding area FR due to repeated folding and unfolding operations. Since each of the first and second magnetic bodies 300a and 300b is provided in a corresponding non-folding area UFR and folding area FR of the magnetic body group 300, the contact area between the second magnetic body 300b, which has a certain stiffness, and the lower plate 200, which adhere to each other by magnetic attraction, can vary during the folding and unfolding operations.

[0171] In some cases, one or more second magnetic bodies 300b may be provided in the folding area FR. Although not shown, the second magnetic bodies 300b may be connected to projections extending from the base of the housing structure 800. In this case, the number of projections may be equal to the number of second magnetic bodies 300b provided in the folding area FR.

[0172] Plate 540 is provided to prevent interference between display panel 100 and circuit board 650, and plate 550 is provided to prevent interference between display panel 100 and battery 700. However, if the lower plate 200 and the magnetic body group 300 provide sufficient shielding, plates 540 and 550 can be omitted.

[0173] A flexible display device according to a second embodiment is described below.

[0174] Fig. Figure 12 is a perspective exploded view showing the unfolded state of the flexible display device according to the second embodiment. Fig. 13A and Fig. Figure 13B shows cross-sectional views of a folding area and peripheral components in the unfolded and folded states of the [unclear text]. Fig. 12 flexible display devices shown.

[0175] As in the Fig. As shown in Figures 12 to 13B, the flexible display device according to the second embodiment differs from the flexible display device according to the first embodiment in that the housing element 400 is divided into two units in the folding area FR, each unit comprising a gear shaft 520, a support frame 450, and a gear 510 with teeth formed around the gear shaft 520, and that the housing element 400 further comprises a joint element 500 for receiving the gear 510 and the gear shaft 520 and for connecting the two divided units. The gear 510 of one of the two units and the gear 510 of the other mesh with each other.

[0176] In the flexible display device according to the second embodiment of the present invention, the support frames 450 in the folding area FR can be arranged such that they are symmetrical to each other on the basis of the hinge element 500 in order to support the lower plate 200 and the second magnetic bodies 300b, and the base panel 400a of the housing element 400 can be formed with an inclination to be arranged in the remaining space, except for the space occupied by the hinge element 500.

[0177] Each of the first and second magnetic bodies 300a and 300b is located in a corresponding area of ​​the non-folding region UFR and the folding region FR of the magnetic body group 300. In particular, two second magnetic bodies 300b are provided, which are arranged symmetrically to each other on the basis of the hinge element 500 and are attached to the lower plate 200.

[0178] The second magnetic bodies 330b, located in the folding area FR, are supported by the support frames 450, which are situated to the left and right of the hinge element 400. The first magnetic body 300a, located in the non-folding area UFR, is supported by a support section projecting from the housing element 400.

[0179] With the exception of the provision of the joint element 500, the housing element in the second embodiment has a configuration with respect to the formation of segments (i.e. two support frames 450) that is similar to the configuration of the housing element in the first embodiment.

[0180] In the second embodiment, the folding area FR of the magnetic body group 300 and the non-folding area UFR of the magnetic body group 300 are individually attached to the lower plate 200. During the folding process, the folding area FR of the magnetic body group 300 is brought into at least line contact with the lower plate 200 in the folding axis direction. Regardless of whether a folding or unfolding process is performed, the non-folding area UFR of the magnetic body group 300 is held in surface contact with the lower plate 200. Therefore, the lower plate 200 and the magnetic body group 300 are held in contact with each other without any interlocking element.

[0181] As a result, the flexible display device according to the second embodiment can exhibit effects that are the same as the previously mentioned effects of the flexible display device according to the first embodiment.

[0182] Fig. Figure 14 is an image showing the lower plate in the folded state in the flexible display device according to the present invention. Fig. Figure 15 is an image showing the folded state in which the lower plate and the magnetic body in the flexible display device are partially separated from each other, according to the present invention.

[0183] The Fig. 14 and Fig. Figure 15 shows the folded state in which the magnetic body group 300, which has a certain stiffness, is separated from the folded area FR of the lower plate 200, which is bent with a certain curvature. In the images of Fig. 14 and Fig. Figure 15 shows only the housing element 400, which is divided into two units in the folding area FR, and the magnet body group 300, which is arranged to correspond to the housing element 400. The hinge element 500 and a section of the magnet body group 300 located at the folded section are omitted. As shown in the figures, the magnet body group 300 is formed only in a plate shape in the non-folding area. Thus, during the folding process, the magnet body group 300 remains flat due to the difference in stiffness between the magnet body group 300 and the lower plate 200, partially separating the folding area of ​​the magnet body group 300 from the lower plate 200.

[0184] The images only show the difference in stiffness between the lower plate 200 and the magnetic body group 300. However, in the flexible display devices according to the first and second embodiments, the magnetic body group 300 has several second magnetic bodies 300b provided in its folding area, and the housing element 400 has several segments provided in the folding area thereof, wherein the magnetic body group 300 (300b) is held in at least line contact with the lower plate 200 in the folding area during the folding process.

[0185] Fig. Figure 16 is a cross-sectional view of a bendable display device according to the present invention.

[0186] As in Fig. As shown in Figure 16, the bendable display device according to the present invention can be divided into a non-bending area UBR, which corresponds to the central section of the device, and bending areas BR, which correspond to the left and right sections of the device. Fig. Figure 16 represents the bent state of the bending areas BR. In the non-bent state, a plate group 2000 is held flat in each of the bending areas BR, like the non-bent area UBR.

[0187] The non-bending area UBR remains flat regardless of whether a bending or re-bending operation is performed. The bending areas BR can be bent with a predetermined curvature on the left and right sides of the device.

[0188] The record group 2000, which in Fig. Figure 16 shows an arrangement of the display panel 100 and the lower plate 200 stacked on top of each other. The plate group 2000 is flat and flexible.

[0189] The display panel 100 and the lower plate 200 can be configured as described above, and a description of this is omitted.

[0190] A group of magnet bodies 1300 can comprise a first magnet body 1300a, located in the non-bending region UBR, and second magnet bodies 1300b, located in the bending regions BR. One or more second magnet bodies 1300b can be located in each of the bending regions BR. In the case where multiple second magnet bodies 1300b are located in each of the bending regions BR, the width of the second magnet bodies 1300b can be varied according to the curvature with which each of the bending regions BR is bent. For example, the width of the second magnet body 1300b located in a section of the bending region BR that is bent with a relatively large curvature can be reduced or omitted, and the width of the second magnet body 1300b located in a section of the bending region BR that is bent with a relatively small curvature can be increased.The first magnetic body 1300a, which is provided in the non-bending area UBR, can be configured as a single body to uniformly support the plate group 2000 and keep the plate group 2000 flat.

[0191] In the bendable display device according to the present invention, the bending regions BR of the magnetic body group 1300 and the non-bending region UBR of the magnetic body group 1300 adhere individually to the lower plate 200. During the bending process, each of the bending regions BR of the magnetic body group 1300 is brought into at least line contact with the lower plate 200 in a bending axis direction. Regardless of whether a bending or re-bending process is performed, the non-bending region UBR of the magnetic body group 1300 is kept in surface contact with the lower plate 200. Therefore, the lower plate 200 and the magnetic body group 1300 (1300a and 1300b) are held in contact with each other without any intervening adhesive element.

[0192] Therefore, the bendable display device according to the present invention can exhibit effects that are the same as the previously mentioned effects of the flexible display devices according to the first and second embodiments.

[0193] The flexible display device, which is in Fig. Figure 16 shows that the device is configured so that it is bendable in both directions. However, a bendable display device with only one bendable side is also possible. In this case, several second magnetic bodies 1300b can be provided in only one bending area.

[0194] In the flexible display device according to the present invention, the magnetic bodies can be arranged such that a deterioration of the flexibility of a specific section, which is to be folded with a predetermined curvature, is prevented. The arrangement of the magnetic bodies can vary according to the arrangement of the folding or bending area.

[0195] As can be seen from the above description, the flexible display device and the electronic device comprising it have the following effects according to the present invention.

[0196] First, when a display panel is attached to a housing element, a lower plate, sized to or similar to the display panel, is positioned facing the panel's surface. This lower plate, which possesses relatively high rigidity, supports the display panel, preventing it from sagging or bending. This maintains rigidity and consequently improves the device's reliability despite repeated folding and unfolding operations. Furthermore, the section of the lower plate corresponding to the folding area is designed with a relatively low density, thus reducing the stress exerted on this area.

[0197] Secondly, when the display panel is attached to the housing element, the lower plate is positioned beneath the display panel, and a group of magnets is located under the lower plate to adhere to it through magnetic attraction. Therefore, no adhesive element is required between the housing element and the display panel, whose materials differ significantly in stiffness and physical properties. This prevents the adhesive element from detaching and prevents the display panel from gradually separating from the housing element through repeated folding and unfolding operations.

[0198] Thirdly, magnetic bodies provided in the folding area of ​​the magnetic body assembly are arranged in accordance with segments distributed across the folding area of ​​the housing element. By providing the magnetic bodies and the housing element segments, which adhere to the magnetic bodies, in the folding area intended to be folded with a large curvature, it is possible to ensure the flexibility of the device.

[0199] Fourth, the surfaces of the magnetic body assembly and the surfaces of the lower plate facing each other are kept flat and are therefore held in surface contact solely by magnetic attraction, without any additional protruding or fastening section. During the folding process, the magnetic body is not completely separated from the lower plate in the folded area but is held in line contact with the lower plate, or partially in contact with it, by magnetic attraction. When returning from the folded to the unfolded state, the entire surface of the magnetic body is brought into contact with the lower plate by magnetic attraction. Therefore, despite repeated folding and unfolding processes, the magnetic body assembly is not completely separated from the lower plate, and the components are thus stably housed within the casing element.

[0200] Fifth, during the folding and unfolding processes, the display panel and the lower plate are actuated together, and the lower plate and the magnetic body assembly adhere to each other by magnetic attraction. Therefore, no adhesive element is required between sections that are separated when the folding process is repeated. This simplifies post-processing, prevents damage to the display panel, and improves the production yield of the device.

[0201] It is obvious to a person skilled in the art that various modifications and variations can be made to the present invention without altering its scope. Therefore, it is intended that the present invention covers such modifications and variations, provided they fall within the scope of protection of the appended claims and their equivalents.

[0202] The following is a list of examples: 1. Flexible display device, comprising: a display panel (100); a lower plate (200) formed from a stainless steel material, wherein the lower plate (200) comprises a first surface facing a bottom of the display panel (100), wherein the lower plate (200) is divided into at least one folding area (FR, BR) and at least one non-folding area (UFR, UBR) adjacent to the folding area (FR, BR), wherein the folding area (FR, BR) has a density that is lower than the density of the non-folding area (UFR, UBR); and a magnetic body group (300, 1300) which is subdivided in accordance with the folding area (FR, BR) and the non-folding area (UFR, UBR), wherein the magnetic body group (300, 1300) is held in contact with a second surface of the lower plate (200) which is opposite to the first surface of the lower plate (200). 2. Flexible display device according to Example 1, wherein the magnetic body group (300, 1300) comprises a single first magnetic body (300a, 1300a) provided in each non-folding region (FR, BR) and at least two second magnetic bodies (300b, 1300b) provided in each folding region (FR, BR), and wherein the first magnetic body (300a, 1300a) and the at least two second magnetic bodies (300b, 1300b) are separate from each other. 3. Flexible display device according to Example 2, wherein the first magnetic body (300a, 1300a) and the at least two second magnetic bodies (300b, 1300b) are held in a folded state in contact with the lower plate (200), and wherein a contact area between the at least two second magnetic bodies (300b, 1300b) and the lower plate (200) in the folded state is smaller than in an unfolded state. 4. Flexible display device according to Example 2 or 3, wherein each of the at least two second magnetic bodies (300b, 1300b) is configured as a single body extending continuously parallel to the folding axis. 5. Flexible display device according to any of the preceding examples, wherein the magnetic body group (300, 1300) occupies an area which constitutes more than 10% of the total area of ​​the non-folding area (UFR, UBR) of the lower plate (200). 6. Flexible display device according to any of the preceding examples, further comprising: an adhesive layer (150) provided between the display panel (100) and the non-folding area (UFR, UBR) of the first surface of the lower plate (200). 7. Flexible display device according to one of the preceding examples, wherein the lower plate (200) comprises several slots (202) formed in the folding area (UFR, UBR). 8. Flexible display device according to Example 7, wherein the multiple slots (200) are arranged parallel to a folding axis of the display panel (200), and wherein the multiple slots (200) are arranged adjacent to each other, so that they do not overlap when viewed in the direction of the folding axis. 9. Flexible display device according to Example 7 or 8, wherein at least one of the slots (202) is formed with a depth less than the thickness of the non-folding area (UFR, UBR) of the lower plate (200). 10. Flexible display device according to any of the preceding examples, further comprising: a metal layer (213) provided on the second surface of the lower plate (200), wherein the metal layer (213) is in direct contact with the magnet body group (300, 1300). 11. Flexible display device according to any of the preceding examples, further comprising: a housing element (400) for receiving the lower plate (200) and the magnetic body group (300, 1300) therein. 12. Flexible display device according to Example 11, characterized in that the housing element (400) comprises several segments (410) facing the folding area (FR, BR), wherein the segments (410) extend parallel to the folding axis, and wherein the second magnetic bodies (300b, 1300b) are arranged in accordance with the segments (410). 13. Flexible display device according to any of the preceding examples, further comprising: a plate that is provided between the magnet body group and the housing element to correspond to the non-folding area. 14. Flexible display device according to any of the preceding examples, further comprising: a flexible printed circuit board connected to one side of the display panel, wherein the flexible printed circuit board extends in such a way that it is folded between the housing element and the magnet body assembly; a circuit board connected to the flexible circuit board; and a battery connected to the circuit board, wherein the battery is located between the housing element and the magnet body group.

Claims

[1] Flexible display device comprising: a display panel (100); a lower plate (200) formed from a stainless steel material, wherein the lower plate (200) comprises a first surface facing a bottom of the display panel (100), wherein the lower plate (200) is divided into at least one folding area (FR, BR) and at least one non-folding area (UFR, UBR) adjacent to the folding area (FR, BR), wherein the folding area (FR, BR) has a mass per unit volume that is less than a mass per unit volume of the non-folding area (UFR, UBR); and several gears (510) under the folding area (FR, BR) of the lower plate (200), a support frame (450) to support the lower plate (200) around the gears (510) in the folding area (FR, BR); a magnetic body group (300, 1300) that is contained in the folding region (FR, BR) and the non-folding region (UFR, UBR), wherein the magnetic body group (300, 1300) is in contact with a second surface of the lower plate (200) that is opposite to the first surface of the lower plate (200). wherein the lower plate (200) comprises several slots (202) formed in the folding area (FR, BR); and wherein the magnetic body group (300, 1300) is in the folding area (FR, BR) between the lower plate (200) and the support frame (450). [2] Flexible display device according to claim 1, wherein each of the gears (510) is formed around a gear shaft (520) and an outer region of the gear (510) has multiple teeth. [3] Flexible display device according to claim 1 or 2, wherein the teeth of adjacent gears (510) in the folding area (FR, BR) are in engagement with each other. [4] Flexible display device according to one of the preceding claims, further comprising a joint element (500) to accommodate the gear (510). [5] Flexible display device according to claim 4, further comprising a housing element (400) which accommodates the lower plate (200) and has an open part to expose the hinge element (500). [6] Flexible display device according to one of the preceding claims, wherein the multiple slots (202) formed in the folding area (UFR, UBR) are random opening patterns that differ from those in the non-folding area (UFR, UBR). [7] Flexible display device according to one of the preceding claims, wherein the multiple slots (202) are arranged in multiple rows and multiple columns, wherein the rows are parallel to a folding axis, and wherein slots (202) that are adjacent to each other in the rows are offset from each other in the column direction. [8] Flexible display device according to claim 7, wherein at least one of the slots (202) formed in the folding area (FR, BR) of the lower plate (200) is formed with a depth that is less than a thickness of the non-folding area (UFR, UBR) of the lower plate (200). [9] Flexible display device according to any of the preceding claims, wherein the magnetic body group (300, 1300) comprises one or more magnetic bodies (300b, 1300b) in relation to the folded area (FR, BR) and separately magnetic bodies (300a, 1300a) in relation to the non-folded area (UFR, UBR), wherein each magnetic body (300b, 1300b) of the magnetic body group (300, 1300) faces and is in contact with the lower plate (200), and wherein a contact area between the magnetic bodies (300b, 1300b) provided in the folded area (FR, BR) and the lower plate (200) is smaller in a folded state than in an unfolded state. [10] Flexible display device according to one of the preceding claims, further comprising an adhesive layer provided between the display panel (100) and the non-folding area (UFR, UBR) of the first surface of the lower plate (200). [11] Flexible display device according to one of the preceding claims, further comprising a metal film provided on the second surface of the lower plate (200) which faces the magnet body group, wherein the metal film is in direct contact with a magnet body of the magnet body group (300, 1300). [12] Flexible display device according to one of the preceding claims, wherein the housing element (400) is connected to the underside of the magnetic body group (300, 1300) using an adhesive element. [13] Flexible display device according to one of the preceding claims, further comprising a plate (540, 550) which is provided between the magnetic body group (300, 1300) and the housing element (400) to correspond to the non-folding area (UFR, UBR). [14] Flexible display device according to any of the preceding claims, further comprising: a flexible printed circuit board (610) which is connected to one side of the display panel (100), wherein the flexible printed circuit board (610) extends such that it is folded between the housing element (400) and the magnet body group (300, 1300); a printed circuit board (650) connected to the flexible printed circuit board (610); and a battery (700) which is connected to the circuit board (650), wherein the battery (700) is located between the housing element (400) and the magnet body group (300, 1300). [15] Flexible display device according to any one of the preceding claims, further comprising: a flexible base substrate, a thin-film transistor arrangement provided on the flexible base substrate, an organic light-emitting diode array connected to the thin-film transistor array, an encapsulation layer for encapsulating the organic light-emitting diode arrangement, a contact electrode arrangement provided on the encapsulation layer, and a protective coating for the contact electrode assembly. [16] Electronic device comprising: a flexible display device according to any one of the preceding claims 1-15; a flexible printed circuit board (610) connected to one side of the display panel (100); a printed circuit board (650) connected to the flexible printed circuit board (610); and a battery (700) which is connected to the circuit board (650).

Images