Cover plate and foldable display device

Abstract

The present disclosure relates to the field of display technology, and more specifically, to a cover plate and a foldable display device. This cover plate is used in a foldable display device, wherein the surface of the cover plate away from the first display panel is the first surface; the first surface includes a central plane and an edge plane, a first edge arc surface, a second edge arc surface and a third edge arc surface that surround the central plane and are sequentially connected end to end; the edge plane and the second edge arc surface are arranged relative to each other in a first direction, and the first edge arc surface and the third edge arc surface are arranged relative to each other in a second direction, and the second direction is perpendicular to the first direction; wherein the edge plane is located on the side of the second edge arc surface close to the foldable area; and the curvature of the first edge arc surface and the third edge arc surface gradually decreases from the second edge arc surface to the edge plane. This solution can improve product reliability.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a cover plate and a foldable display device. Background Art

[0002] At present, foldable display products (such as foldable mobile phones) are rapidly emerging. For inward foldable display products, a secondary display screen is usually installed on the back of the foldable display product as one of the usage scenarios; the size of this secondary display screen is usually half of the size of the main display screen, installed on the whole machine, with three sides adjacent to the frame of the foldable display product and the other side located in the middle of the foldable display product. Among them, adding a secondary display screen on the back of the foldable display product can make the foldable display product have a variety of usage scenarios, but it will reduce the reliability of the foldable display product. For example, the secondary display screen is easily damaged during the drop test.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] The purpose of the present disclosure is to provide a cover plate and a foldable display device, which improves product reliability.

[0005] According to a first aspect of the present disclosure, there is provided a cover plate for a foldable display device, wherein the foldable display device comprises a first area, a second area, and a foldable area connecting the first area and the second area, wherein the foldable display device comprises a first display panel located in the first area, and the cover plate can be located in the first area and arranged on a display side of the first display panel;

[0006] The surface of the cover plate away from the first display panel is the first surface; the first surface includes a central plane and an edge plane, a first edge curved surface, a second edge curved surface and a third edge curved surface that surround the central plane and are sequentially connected end to end; the edge plane and the second edge curved surface are arranged opposite to each other in a first direction, the first edge curved surface and the third edge curved surface are arranged opposite to each other in a second direction, and the second direction is perpendicular to the first direction;

[0007] The edge plane is located on a side of the second edge arc surface close to the foldable area; and the curvatures of the first edge arc surface and the third edge arc surface gradually decrease from the second edge arc surface to the edge plane.

[0008] In an exemplary embodiment of the present disclosure,

[0009] The curvature of the first edge arc surface at the junction with the edge plane is 0;

[0010] The curvature of the third edge arc surface at a portion where it meets the edge plane is 0.

[0011] In an exemplary embodiment of the present disclosure,

[0012] The width of the first edge arc surface at the junction with the edge plane is W1, the width of the first edge arc surface at the junction with the second edge arc surface is W2, and the ratio of W2 to W1 is 0.5 to 0.8;

[0013] The width of the third edge arc surface at the edge plane is W3, the width of the third edge arc surface at the second edge arc surface is W4, and the ratio of W4 to W3 is 0.5 to 0.8;

[0014] The width is the dimension in the second direction.

[0015] In an exemplary embodiment of the present disclosure,

[0016] The curvature of the second edge arc surface at each location in the second direction is the same.

[0017] In an exemplary embodiment of the present disclosure,

[0018] A surface of the cover plate close to the first display panel is a second surface, wherein the second surface is a plane.

[0019] In an exemplary embodiment of the present disclosure,

[0020] The surface of the cover plate close to the first display panel is the second surface, wherein:

[0021] The area of ​​the second surface opposite to the central plane and the area opposite to the edge plane are both planes;

[0022] The area of ​​the second surface opposite to the first edge arc surface, the area opposite to the second edge arc surface, and the area opposite to the third edge arc surface are all arc surfaces.

[0023] In an exemplary embodiment of the present disclosure,

[0024] The curvature of the area of ​​the second surface opposite to the first edge arc surface is the same as the curvature of the first edge arc surface;

[0025] The curvature of the area of ​​the second surface opposite to the second edge arc surface is the same as the curvature of the second edge arc surface;

[0026] The curvature of a region of the second surface opposite to the third edge arc surface is the same as the curvature of the third edge arc surface.

[0027] A second aspect of the present disclosure provides a foldable display device, wherein the foldable display device has a first area, a second area, and a foldable area connected between the first area and the second area, wherein the foldable display device includes a first display panel and a first cover plate located in the first area, the first cover plate is arranged on the display side of the first display panel, and the first cover plate is any one of the cover plates described above.

[0028] In an exemplary embodiment of the present disclosure,

[0029] The first display panel has a display area and a non-display area surrounding the display area, the display area has a first boundary and a second boundary opposite to each other in the second direction, and both the first boundary and the second boundary extend in the first direction;

[0030] The boundary of the first edge arc surface connected to the central plane is a third boundary, and the third boundary intersects with the first boundary, and the intersection point is a first intersection point;

[0031] The boundary of the third edge arc surface that is connected to the central plane is a fourth boundary, and the fourth boundary intersects with the second boundary, and their intersection is a second intersection point; wherein,

[0032] The ratio of the length of the line segment in the first boundary located at the first intersection close to the second edge arc surface to the length of the line segment in the first boundary located at the first intersection close to the edge plane is 0.2 to 0.5;

[0033] A ratio of a length of a line segment in the second boundary located at the second intersection point close to the second edge arc surface to a length of a line segment in the second boundary located at the second intersection point close to the edge plane is 0.2 to 0.5.

[0034] In an exemplary embodiment of the present disclosure,

[0035] The first display panel is flexible; the first display panel includes a display portion, a binding portion located at the back side of the display portion, and a bending portion connecting the display portion and the binding portion; the first cover plate is provided on the display side of the display portion, and the display portion includes the display area and the non-display area;

[0036] Among them, a part of the orthographic projection of the binding part on the reference plane is located within the orthographic projection of the third edge arc surface on the reference plane, and the other part is located within the orthographic projection of the center plane on the reference plane, and the reference plane is a plane parallel to the center plane.

[0037] In an exemplary embodiment of the present disclosure,

[0038] The foldable display device further includes a second display panel and a second cover plate located in the first area, the second area, and the foldable area;

[0039] The second display panel and the second cover plate are flexible, a side of the second display panel away from the first display panel is a display side, the second cover plate is located on the display side of the second display panel, and an outer contour of the second cover plate exceeds an outer contour of the second display panel.

[0040] The technical solution provided by the present disclosure can achieve the following beneficial effects:

[0041] The cover plate and the foldable display device provided by the present disclosure are configured such that the area on the outer surface (i.e., the first surface) of the cover plate, which is located at the edge of the foldable display device, is formed into an arc surface, namely, a first edge arc surface, a second edge arc surface, and a third edge arc surface. On the one hand, stress concentration can be avoided at the edge of the cover plate during a drop test, thereby avoiding damage to the cover plate and improving the product reliability of the foldable display device during a drop test. On the other hand, the contact area between the cover plate and the user's hand can be appropriately increased to appropriately alleviate the concentrated stress generated by the edge of the cover plate on the user's hand during hand-holding, thereby improving the user experience.

[0042] In addition, by setting the area in the middle of the foldable display device on the outer surface of the cover plate as a plane, that is, an edge plane; on the one hand, when the foldable display device is in an unfolded state, the gap generated in the middle of the back side of the foldable display device (that is, the plane where the first surface of the cover plate is located) can be reduced, thereby improving the product quality; on the other hand, the support area of ​​the back side of the foldable display device can be increased, so that when the back side of the foldable display device is used as a supporting surface, the problem of stress concentration in the middle of the back side can be alleviated, thereby extending the service life of the product.

[0043] In order to achieve a smooth transition at the edge of the first cover plate, the curvatures of the first edge arc surface and the third edge arc surface need to gradually decrease from the second edge arc surface to the edge plane, so as to avoid the problem of stress concentration caused by contact due to excessive difference in curvature between the first edge arc surface and the third edge arc surface and the edge plane, thereby improving the structural strength of the first cover plate and extending its service life.

[0044] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0046] Figure 1 A schematic diagram showing the structure of a foldable display device in a folded state according to an embodiment of the present disclosure is shown;

[0047] Figure 2 A schematic diagram showing the structure of a foldable display device in an unfolded state according to an embodiment of the present disclosure is shown;

[0048] Figure 3 A schematic structural diagram of a foldable display device in an unfolded state according to another embodiment of the present disclosure is shown;

[0049] Figure 4 Shows Figure 2 A schematic cross-sectional view of a foldable display device along line PP according to an embodiment of the present invention;

[0050] Figure 5 Shows Figure 2 A schematic cross-sectional view of a foldable display device along line NN according to an embodiment of the present invention;

[0051] Figure 6 Shows Figure 2 A schematic cross-sectional view of a foldable display device along line NN according to another embodiment of the present invention;

[0052] Figure 7 Shows Figure 2 A schematic cross-sectional view of a foldable display device along line NN according to another embodiment of the present invention;

[0053] Figure 8 Shows Figure 2 A schematic cross-sectional view of a foldable display device along line MM according to another embodiment;

[0054] Fig. 9 A schematic structural diagram of a foldable display device in another embodiment of the present disclosure in an unfolded state is shown;

[0055] Fig.10 Shows Fig. 9 A schematic side view of a first cover plate of a foldable display device according to an embodiment;

[0056] Fig.11 Shows Fig. 9 A schematic side view of a first cover plate of a foldable display device according to another embodiment;

[0057] Fig.12 Shows Fig. 9 A schematic plan view of a first cover plate of a foldable display device according to an embodiment of the present invention from an external perspective;

[0058] Fig.13a Shows Fig.12 A schematic cross-sectional view of the first cover plate along line QQ according to an embodiment of the present invention;

[0059] Fig.13b Shows Fig.12 A schematic cross-sectional view of the first cover plate along line RR according to an embodiment of the present invention;

[0060] Fig.13c Shows Fig.12 A schematic cross-sectional view of the first cover plate along line TT according to an embodiment of the present invention;

[0061] Fig.13d Shows Fig.12 A schematic cross-sectional view of the first cover plate along line HH according to an embodiment;

[0062] Fig.14a Shows Fig.12 A schematic cross-sectional view of the first cover plate along line RR according to another embodiment of the present invention;

[0063] Fig.14b Shows Fig.12 A schematic cross-sectional view of the first cover plate along line TT according to another embodiment of the present invention;

[0064] Fig.14c Shows Fig.12 A schematic cross-sectional view of the first cover plate along line HH according to another embodiment of the present invention;

[0065] Fig.15 Shows Fig. 9 A schematic plan view of a first cover plate of a foldable display device according to an embodiment of the present invention from an external perspective.

[0066] Reference numerals:

[0067] 10. First display panel; 10a. Display portion; 10b. Binding portion; 10c. Bend portion; 11. First flexible circuit board; 110. First portion; 111. Second portion; 112. Bend portion; 12. Rigid diaphragm; 13. First main circuit board; 14. First connecting terminal; 15. Matching terminal; 16. Buffer portion; 17. First mounting plate; 170. First mounting surface; 170a. Avoidance groove; 170b. First assembly groove; 170c. Second assembly groove; 171. Second mounting surface; 18. First side plate; 19. First mounting groove; 20. Hinge mechanism; 21. Second mounting plate; 210. Third mounting surface; 211. Fourth mounting surface; 22. The second display panel; 220, display substrate; 221, second heat dissipation film layer; 23, second main circuit board; 24, second flexible circuit board; 25, second connecting terminal; 26, second side plate; 27, third side plate; 28, second mounting groove; 29, first cover plate; 29a, first surface; 29b, second surface; 290, center plane; 291, edge plane; 292, first edge arc surface; 293, second edge arc surface; 294, third edge arc surface; 30, second cover plate; 31, third mounting plate; 32, third mounting groove; 33, fourth side plate; 34, adhesive layer; 36, first heat dissipation film layer; 37, raised film portion; 38, strain neutral adhesive layer. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the embodiments of the present disclosure will be described in detail in conjunction with the accompanying drawings below. Note that the embodiments can be implemented in multiple different forms. A person of ordinary skill in the art can easily understand the fact that the methods and contents can be transformed into various forms without departing from the purpose and scope of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited to the contents described in the following embodiments. In the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other.

[0069] In the drawings, the size of each component, the thickness of a layer, or the area is sometimes exaggerated for the sake of clarity. Therefore, one embodiment of the present disclosure is not necessarily limited to this size, and the shape and size of each component in the drawings do not reflect the true proportion. In addition, the drawings schematically show ideal examples, and one embodiment of the present disclosure is not limited to the shapes or values ​​shown in the drawings.

[0070] It should be noted that, the term “on” as used herein may mean that one layer is directly formed or disposed on another layer, or may mean that one layer is indirectly formed or disposed on another layer, that is, there are other layers between the two layers.

[0071] The terms "a", "an", "the", and "this" are used to indicate the presence of one or more elements / components / etc.; the term "comprising" is used to indicate an open-ended inclusion and means that additional elements / components / etc. may exist in addition to the listed elements / components / etc.

[0072] In the present specification, ordinal numbers such as “first” and “second” are provided to avoid confusion among constituent elements, and are not intended to limit the number.

[0073] In this specification, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate, or the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0074] The present disclosure provides a foldable display device having a first area S1, a second area S2, and a foldable area S3 connected between the first area S1 and the second area S2; Figure 1 As shown, the foldable display device can have a folded state. When the foldable display device is in the folded state, the foldable area S3 can be bent as a whole, and the first area S1 and the second area S2 are arranged in the thickness direction Z of the foldable display device; Figure 2 and Figure 3 As shown, the foldable display device can also have an unfolded state. When the foldable display device is in the unfolded state, the foldable area S3 can be flat as a whole, and the first area S1 and the second area S2 are arranged in a first direction X, and the first direction X is perpendicular to the thickness direction Z of the foldable display device.

[0075] It should be noted that if Figure 1 As shown, the foldable area S3 of the embodiment of the present disclosure can be completely exposed relative to the first area S1 and the second area S2 when the foldable display device is in a folded state. When the foldable display device is in an unfolded state, the foldable area S3 of the embodiment of the present disclosure can be completely exposed relative to the first area S1 and the second area S2. Figure 2 As shown; but not limited thereto, the foldable area S3 of the embodiment of the present disclosure may also be at least partially hidden in the first area S1 and the second area S2 when the foldable display device is in the unfolded state, referring to Figure 3 shown.

[0076] In addition, it should be noted that when the foldable display device is in a folded state, the entire first area S1 and the entire second area S2 are substantially not bent.

[0077] The structure of the foldable display device according to the embodiment of the present disclosure is described in detail below with reference to the accompanying drawings.

[0078] The foldable display device may include a first display panel 10 and a first cover plate 29 located in the first area S1, and the first cover plate 29 is arranged on the display side of the first display panel 10; the first cover plate 29 and the first display panel 10 as a whole may constitute a display screen of the foldable display device.

[0079] It should be noted that, as mentioned above, when the foldable display device is in the folded state, the first area S1 as a whole is basically not bent, so the first cover plate 29 can be a glass cover plate with poor flexibility (i.e., not easy to deform), but is not limited thereto, and can also be a cover plate made of a polymer with good flexibility (i.e., easy to deform). Similarly, the first display panel 10 can be a hard panel that is not easy to deform, or a flexible panel that is easy to deform.

[0080] For example, the first display panel 10 of the embodiment of the present disclosure may be a flexible panel, that is, the first display panel may be flexible. Specifically, Figure 4 As shown, the first display panel 10 may include a display portion 10a, a binding portion 10b located on the back side of the display portion 10a, and a bending portion 10c connecting the display portion 10a and the binding portion 10b. The display portion 10a may be an OLED (Organic Light Emitting Diode) display, but is not limited thereto. It should be understood that the first cover plate 29 mentioned above needs to be arranged on the display side of the display portion 10a, that is, the first cover plate 29 is arranged on the side of the display portion 10a away from the binding portion 10b. The first cover plate 29 may be bonded to one side of the display portion 10a through an adhesive layer 34. In addition, it should be noted that the structure of the first display panel 10 of the embodiment of the present disclosure is not limited to the bending structure mentioned above, and may also be a planar structure as a whole.

[0081] Alternatively, if Figure 4 As shown, a first heat dissipation film layer 36 may be provided on the back side of the display portion 10a; the orthographic projection of the first heat dissipation film layer 36 on the display portion 10a is located inside the display portion 10a or overlaps with it; for example, the first heat dissipation film layer 36 may be a multi-layer structure, and the first heat dissipation film layer 36 may include an EMBO (embossed silicone cushioning material) layer, a Foam (foam material) layer, a PI (polyimide film) layer, a Cu (copper) foil layer, and an absorbing material layer, etc., which are arranged in sequence; but not limited to this, the first heat dissipation film layer 36 may also be composed of other film layers, as long as it can ensure that the first heat dissipation film layer 36 has good heat dissipation performance and bendability. In addition, the first heat dissipation film layer 36 may also be a single-layer structure, depending on the specific situation.

[0082] Among them, Figure 4As shown, a padding film layer 37 may be provided between the first heat dissipation film layer 36 and the binding portion 10 b . The padding film layer 37 may ensure the bending curvature and bending stability of the first display panel 10 .

[0083] In addition, if Figure 4 As shown, the outer side of the bending portion 10c may be covered with a strain-neutral adhesive layer 38, and the strain-neutral adhesive layer 38 may also cover the edge portions of the display portion 10a and the binding portion 10b; by providing the strain-neutral adhesive layer 38, the bending portion 10c may be protected to prevent it from breaking during the bending process; for example, the strain-neutral adhesive layer 38 may be an organic adhesive material.

[0084] In one embodiment of the present disclosure, Figure 5 As shown, the foldable display device may further include a first flexible circuit board 11 and a rigid film 12, wherein:

[0085] The first flexible circuit board 11 can be arranged on a side of the first heat dissipation film layer 36 away from the display portion 10a; Figure 5 As shown, the first flexible circuit board 11 may include a first portion 110, a second portion 111, and a bent portion 112 connecting the first portion 110 and the second portion 111. Specifically, the orthographic projection of the bent portion 112 on the display portion 10a may be located in the display area of ​​the display portion 10a; the first portion 110 may be electrically connected to the binding portion 10b; the second portion 111 may be located on a side of the first portion 110 away from the display portion 10a. It should be understood that Figure 6 As shown, the display device of the embodiment of the present disclosure may also include a first main circuit board 13, and the second part 111 may be electrically connected to the first main circuit board 13. It should be noted that the first main circuit board 13 may be located on a side of the second part 111 away from the first part 110.

[0086] like Figure 5 and Figure 6 As shown, a rigid film 12 may be provided between the side of the first heat dissipation film layer 36 away from the display portion 10a and the curved portion 112; the orthographic projection of the rigid film 12 on the display portion 10a may be located within the orthographic projection of the first heat dissipation film layer 36 on the display portion 10a; and the rigid film 12 may support the curved portion 112 of the first flexible circuit board 11. It should be understood that the rigidity of the rigid film 12 may be greater than the rigidity of the first heat dissipation film layer 36 and the display portion 10a, that is, the rigid film 12 is less likely to deform under force than the display portion 10a and the first heat dissipation film layer 36. For example, the material of the rigid film 12 may be polyimide (PI) or stainless steel (SUS), and it should be understood that the PI material used to make the rigid film 12 should be a hard PI material.

[0087] In addition, the thickness of the rigid diaphragm 12 can be 0.1mm to 0.5mm, such as: 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, etc. By designing the thickness of the rigid diaphragm 12 to be greater than or equal to 0.1mm, it is ensured that the rigid diaphragm 12 has sufficient rigidity, and by designing the thickness of the rigid diaphragm 12 to be less than or equal to 0.5mm, the overall thickness of the product can be reduced.

[0088] In the embodiment of the present disclosure, since a rigid diaphragm 12 is provided between the bent portion 112 of the first flexible circuit board 11 and the back side of the display portion 10a, and the rigid diaphragm 12 is not easily deformed when subjected to force, during the installation process, the rigid diaphragm 12 can disperse and release the rebound force generated by the bent portion 112. Therefore, it is possible to avoid the situation where obvious mold marks are generated at the position corresponding to the bent portion 112 in the display area of ​​the display portion 10a, thereby improving the display effect.

[0089] It should be noted that the bent portion 112 of the first flexible circuit board 11 of the embodiment of the present disclosure is not limited to being disposed in the display area of ​​the display portion 10 a , but may also be disposed in the non-display area.

[0090] In the embodiment of the present disclosure, the installation process may be: firstly electrically connect the second portion 111 of the first flexible circuit board 11 to the first main circuit board 13, and then bend the first flexible circuit board 11 to form the aforementioned bent portion 112 and make the first portion 110 be located on the side of the second portion 111 away from the first main circuit board 13. It should be noted that the first portion 110 may be electrically connected to the binding portion 10b before the second portion 111 is electrically connected to the first main circuit board 13, or the first portion 110 may be electrically connected to the binding portion 10b when it is bent to the side of the second portion 111 away from the first main circuit board 13.

[0091] like Figure 6 As shown, the first main circuit board 13 may be provided with a first connecting terminal 14, and the second part 111 of the first flexible circuit board 11 may be provided with a mating terminal 15 that can be snapped or inserted with the first connecting terminal 14, that is: the electrical connection between the first main circuit board 13 and the second part 111 is achieved by snapping or inserting the mating terminal 15 with the first connecting terminal 14.

[0092] In the embodiment of the present disclosure, the bending axis corresponding to the bending portion 112 of the first flexible circuit board 11 can be in the second direction Y (eg Figures 2 to 4 ), and the orthographic projection of the curved portion 112 on the display portion 10a has a first boundary A and a second boundary B opposite to each other in the first direction X. It should be noted that the second boundary B is a side of the curved portion 112 close to the first portion 110 and the second portion 111, and the first boundary A is a side of the curved portion 112 away from the first portion 110 and the second portion 111. Figure 5and Figure 6 and the orthographic projection of the rigid diaphragm 12 on the display portion 10a has a third boundary C and a fourth boundary D opposite in the first direction X, as shown in FIG. Figure 5 and Figure 6 As shown, the third boundary C is located on the side of the first boundary A away from the second boundary B, and the fourth boundary D is located on the side of the second boundary B away from the first boundary A.

[0093] In this embodiment, by locating the first boundary A and the second boundary B of the curved portion 112 on the inner side of the third boundary C and the fourth boundary D of the rigid diaphragm 12, the rigid diaphragm 12 can better disperse the rebound force generated by the curved portion 112. Specifically, compared with the solution in which the first boundary A and the second boundary B of the curved portion 112 are located on the outer side of the third boundary C and the fourth boundary D of the rigid diaphragm 12, the rebound force generated by the curved portion 112 can be avoided from being concentrated on the third boundary C and the fourth boundary D of the rigid diaphragm 12, thereby avoiding the situation in which molds are generated at the positions corresponding to the third boundary C and the fourth boundary D of the rigid diaphragm 12 in the display portion 10a, thereby avoiding improving the display effect.

[0094] It should be noted that the first direction X and the second direction Y mentioned in the embodiment of the present disclosure are perpendicular to each other; and both the first direction X and the second direction Y are perpendicular to the thickness direction Z of the foldable display device.

[0095] Optionally, the distance between the third boundary C of the rigid diaphragm 12 and the first boundary A of the curved portion 112 in the first direction X may be equal to the distance between the fourth boundary D of the rigid diaphragm 12 and the second boundary B of the curved portion 112 in the first direction X, so as to ensure the uniformity of the force on the entire rigid diaphragm 12 and better disperse the stress; but not limited to this, the distance between the third boundary C of the rigid diaphragm 12 and the first boundary A of the curved portion 112 in the first direction X may also be unequal to the distance between the fourth boundary D of the rigid diaphragm 12 and the second boundary B of the curved portion 112 in the first direction X.

[0096] In the embodiment of the present disclosure, the distance between the third boundary C of the rigid diaphragm 12 and the first boundary A of the curved portion 112 in the first direction X may be greater than or equal to 1 cm; the distance between the fourth boundary D of the rigid diaphragm 12 and the second boundary B of the curved portion 112 in the first direction X is greater than or equal to 1 cm. This design enables the rigid diaphragm 12 to better disperse stress.

[0097] It should be noted that the area of ​​the rigid diaphragm 12 in the embodiment of the present disclosure can be determined according to actual conditions, as long as it can better disperse the stress to avoid installation mold printing.

[0098] In some embodiments of the present disclosure, Figure 6As shown, a buffer portion 16 may be provided in the bending space of the bent portion 112, and the orthographic projection of the buffer portion 16 on the display portion 10a is located within the orthographic projection of the rigid diaphragm 12 on the display portion 10a; specifically, the buffer portion 16 may be provided at a position of the bent portion 112 close to the first portion 110, and the orthographic projection of the buffer portion 16 on the display portion 10a is located in the central area of ​​the orthographic projection of the rigid diaphragm 12 on the display portion 10a.

[0099] In this embodiment, a buffer portion 16 is provided in the bending space of the bending portion 112. Such a design enables the buffer portion 16 to provide a certain buffer force for the bending portion 112, so as to ensure that the bending portion 112 has a good ability to recover deformation, thereby avoiding the situation where the bending portion 112 forms a dead bend during the installation process.

[0100] It should be understood that the foldable display device of the embodiment of the present disclosure may further include a middle frame structure, and the middle frame structure includes a first middle frame located in the first area S1, as described in detail, Figure 7 As shown, the first middle frame may include a first mounting plate 17 and a first side plate 18, wherein the first mounting plate 17 has a first mounting surface 170 and a second mounting surface 171 opposite to each other, and the first side plate 18 is arranged on the periphery of the first mounting surface 170, and forms a first mounting groove 19 with the first mounting surface 170; it should be noted that when the first mounting surface 170 is a rectangle, the first side plate 18 may be arranged around the four sides of the first mounting surface 170, but is not limited to this, and may also be arranged on three sides, or on two opposite sides, etc., depending on the specific circumstances.

[0101] The first display panel 10, the first flexible circuit board 11, the rigid film 12, the first main circuit board 13, the first connection terminal 14, the mating terminal 15, and the buffer portion 16 mentioned above can be located in the first mounting groove 19. Specifically, the first portion 110 is located on the side of the second portion 111 away from the first mounting surface 170. It should be noted that, if Figure 7 As shown, the first mounting surface 170 may be provided with an avoidance groove 170a corresponding to the bending portion 112, and the first mounting surface 170 may be provided with a first assembly groove 170b; the aforementioned first main circuit board 13 may be specifically located in the first assembly groove 170b, and a portion of the first connecting terminal 14 extends out of the first assembly groove 170b and is plugged or snapped into place with the mating terminal 15 on the second portion 111.

[0102] Optionally, the edge of the first cover plate 29 exceeds the edge of the display portion 10a, and the portion of the first cover plate 29 exceeding the display portion 10a can be placed on the end surface of the first side plate 18 away from the first mounting surface 170; specifically, a positioning groove can be provided on the end surface of the first side plate 18 away from the first mounting surface 170, and the portion of the first cover plate 29 exceeding the display portion 10a can be placed on the positioning groove of the first side plate 18, refer to Figure 7 shown.

[0103] It should be understood that the middle frame structure in the embodiment of the present disclosure may be a folding mechanism, and in addition to the first middle frame located in the first area S1 mentioned above, it may also include a second middle frame rotatably connected to the first middle frame and located in the second area S2, such as Figure 8 As shown, the second middle frame can be rotatably connected to the first middle frame via a hinge mechanism 20, and the hinge mechanism 20 can be located in the foldable area S3.

[0104] Among them, Figure 8 As shown, the second middle frame may include at least a second mounting plate 21, and the second mounting plate 21 has a third mounting surface 210 and a fourth mounting surface 211 relative to each other, wherein the relative rotation of the first middle frame and the second middle frame can enable the third mounting surface 210 to rotate to a position facing the second mounting surface 171.

[0105] Alternatively, if Figure 8 As shown, the foldable display device of the embodiment of the present disclosure may also include a second display panel 22 located in the first area S1, the second area S2 and the foldable area S3. The second display panel 22 may be located on a side of the second mounting surface 171 away from the first mounting surface 170 and on a side of the third mounting surface 210 away from the fourth mounting surface 211. It should be understood that the side of the second display panel 22 facing the second mounting surface 171 and the third mounting surface 210 is the back side of the second display panel 22, and the side of the second display panel 22 away from the second mounting surface 171 and the third mounting surface 210 is the display side; for example, Figure 8 As shown, the second display panel 22 may include a display substrate 220 and a second heat dissipation film layer 221 , and the second heat dissipation film layer 221 may be disposed on the back side of the display substrate 220 ; the orthographic projection of the second heat dissipation film layer 221 on the display substrate 220 is located within the display substrate 220 or overlaps with it.

[0106] In addition, the structure of the second heat dissipation film layer 221 may be the same as that of the first heat dissipation film layer 36 mentioned above, and will not be repeated here.

[0107] Among them, the second display panel 22 can be a flexible display panel, that is, the second display panel 22 is flexible, and when the first middle frame and the second middle frame rotate relative to each other so that the third mounting surface 210 rotates to a position facing the second mounting surface 171, the second display panel 22 can be bent, that is, the entire foldable display device can be folded inward, that is, the display surface of the display substrate 220 is located on the inner side of the bend.

[0108] In the embodiments of the present disclosure, Figure 8As shown, the foldable display device may further include a second main circuit board 23 and a second flexible circuit board 24; wherein the second main circuit board 23 may be disposed on the first mounting plate 17 or the second mounting plate 21, and a second connecting terminal is disposed on the second main circuit board 23; one end of the second flexible circuit board 24 is electrically connected to the second connecting terminal 25, and the other end is electrically connected to the second display panel 22. It should be noted that one end of the second flexible circuit board 24 may be bound to the second display panel 22 at the display side of the second display panel 22; but not limited thereto, a portion of the second display panel 22 may also be bent away from its display side to form a binding portion, and then electrically connected to the second flexible circuit board 24.

[0109] For example, Figure 8 As shown, a second assembly groove 170c may also be provided on the aforementioned first mounting surface 170, and a through hole (not shown in the figure) penetrating the first mounting surface 170 and the second mounting surface 171 may also be provided on the first mounting plate 17, and this through hole is connected to the second assembly groove 170c; the second main circuit board 23 and the second connecting terminal 25 are located in the second assembly groove 170c, and one end of the second flexible circuit board 24 passes through the through hole and is electrically connected to the second connecting terminal 25.

[0110] It should be noted that the second main circuit board 23 and the first main circuit board 13 can be an integrated structure or independently arranged. It should be understood that when the second main circuit board 23 and the first main circuit board 13 are an integrated structure, the first assembly groove 170b and the second assembly groove 170c can be interconnected.

[0111] In the embodiments of the present disclosure, Figure 8 As shown, a second side panel 26 may be provided around the second mounting surface 171 of the first mounting plate 17. It should be understood that the second side panel 26 may not be provided on one side of the second mounting surface 171 adjacent to the third mounting surface 210, and the other three sides may be provided, but not limited to this; a third side panel 27 may be provided around the third mounting surface 210 of the second mounting plate 21. It should be understood that the third side panel 27 may not be provided on one side of the third mounting surface 210 adjacent to the second mounting surface 171, and the other three sides may be provided, but not limited to this; wherein, the second side panel 26, the second mounting surface 171, the third mounting surface 210 and the third side panel 27 may form a second mounting groove 28, and the aforementioned second display panel 22 and the second flexible circuit board 24 may be located in the second mounting groove 28.

[0112] like Figure 8As shown, the foldable display device of the embodiment of the present disclosure may also include a second cover plate 30 located in the first area S1, the second area S2 and the foldable area S3, and the second cover plate 30 is located on the display side of the second display panel 22, that is, the second cover plate 30 may be arranged on the side of the second display panel 22 away from the second mounting surface 171 and the third mounting surface 210, and the second cover plate 30 and the second display panel 22 may constitute another display screen of the foldable display device. The edge of the second cover plate 30 may also exceed the edge of the second display panel 22; the outer contour of the second cover plate 30 may exceed the outer contour of the second display panel 22.

[0113] It should be noted that the second cover plate 30 may be a flexible cover plate, for example, it may be made of a polymer material, that is, the second cover plate 30 can be bent. Specifically, when the first middle frame and the second middle frame rotate relative to each other so that the third mounting surface 210 rotates to a position facing the second mounting surface 171, the second cover plate 30 can bend along with the second display panel 22.

[0114] Among them, Figure 8 As shown, a fourth side panel 33 may also be provided around the fourth mounting surface 211. It should be noted that when the fourth mounting surface 211 is a rectangle, the fourth side panel 33 may be provided around the four sides of the fourth mounting surface 211, but is not limited thereto. It may also be provided on three sides, or on two opposite sides, etc., depending on the specific circumstances.

[0115] In addition, the second middle frame may further include a third mounting plate 31 opposite to the second mounting plate 21, and the fourth side plate 33 may form a third mounting groove 32 with the third mounting plate 31 and the fourth mounting surface 211 of the second mounting plate 21, and the display device may further include a battery (not shown in the figure) and other structures, and the battery may be placed in the third mounting groove 32, but is not limited thereto, and other structures may be provided in the third mounting groove 32. It should be noted that the second middle frame of the embodiment of the present disclosure may not include the third mounting plate 31, depending on the specific situation.

[0116] It should be noted that the first middle frame of the embodiment of the present disclosure may be an integrated structure as a whole, and the second middle frame may also be an integrated structure as a whole.

[0117] In an embodiment of the present disclosure, a display screen formed by the aforementioned first display panel 10 and the first cover plate 29 can be a sub-display screen of the entire foldable display device, and a display screen formed by the aforementioned second display panel 22 and the second cover plate 30 can be a main display screen of the entire foldable display device. When the foldable display device is in an unfolded state, the main display screen can be mainly used for display, but not limited to this, and the sub-display screen can also be used for display; and when the foldable display device is in a folded state, the sub-display screen can be used for display.

[0118] It should be noted that when the foldable display device is in the unfolded state, the side where the secondary display screen is located can be the back side of the entire foldable display device, and the side where the main display screen is located can be the front side of the entire foldable display device. In addition, the main display screen and the secondary display screen of the embodiment of the present disclosure can be designed as a rectangle as a whole.

[0119] In the embodiments of the present disclosure, the specific type of the foldable display device is not particularly limited, and any type of display device commonly used in the art can be used, such as mobile phones, tablet computers, etc. Those skilled in the art can make corresponding choices based on the specific purpose of the display device, which will not be repeated here.

[0120] It should be noted that in addition to the aforementioned structure, the foldable display device also includes other necessary components and components. Taking a mobile phone as an example, these include a front cover, a back cover, a touch function layer, a polarizer, a power cord, etc. Those skilled in the art can make corresponding supplements based on the specific usage requirements of the display device, which will not be elaborated here.

[0121] Based on the foregoing, it can be seen that the main display screen of the embodiment of the present disclosure is located in the entire area of ​​the foldable display device, and the four sides of the main display screen are close to the edges of the entire foldable display device. Therefore, in order to improve the reliability of the main display screen during the drop test, the edge portions of the second cover plate 30 located at the four sides can be set to be arc-shaped; specifically, Figure 8 As shown, the surface of the edge of the second cover plate 30 away from the second display panel 22 can be set to an arc surface, and this arc surface can be produced by mechanical processing; or, the edge of the second cover plate 30 can be bent as a whole to form an arc structure, for example, it can be bent by hot bending or other processing methods.

[0122] In the embodiment of the present disclosure, the edge portions of the second cover plate 30 at the four sides are all arranged to be arc-shaped, so that the problem of stress concentration at the edge of the second cover plate 30 can be avoided during the drop test, thereby avoiding damage to the cover plate; in addition, when the edge portion of the second cover plate 30 is bent as a whole to form an arc structure, the edge of the second display panel 22 can also be bent together with the edge portion of the second cover plate 30 to form an arc structure; this can facilitate the realization of full-screen display.

[0123] It should be understood that the present disclosure is not limited to setting the edge portions at the four sides of the second cover plate 30 to be arc-shaped, and the edge portions at the two opposite sides of the second cover plate 30 may also be set to be arc-shaped, depending on the specific product requirements.

[0124] In addition, based on the above content, it can be known that the secondary display screen of the embodiment of the present disclosure is located in half of the area of ​​the foldable display device, and only three sides of this secondary display screen are close to the edge of the entire foldable display device, and the other side is close to the middle area of ​​the entire foldable display device. Among them, in order to improve the product reliability of the secondary display screen, the structure of the first cover plate 29 is designed in the embodiment of the present disclosure, and the structure of the first cover plate 29 is described in detail below with reference to the accompanying drawings.

[0125] In the embodiments of the present disclosure, Fig.10 and Fig.11 As shown, the surface of the first cover plate 29 away from the first display panel 10 may be the first surface 29a, that is, the first surface 29a is the outer surface of the first cover plate 29; the surface of the first cover plate 29 close to the first display panel 10 may be the second surface 29b, that is, the second surface 29b is the inner surface of the first cover plate 29; wherein:

[0126] like Fig.12 As shown, the first surface 29a may include a central plane 290 and an edge plane 291, a first edge arc surface 292, a second edge arc surface 293 and a third edge arc surface 294 that surround the central plane 290 and are sequentially connected end to end; the edge plane 291 and the second edge arc surface 293 are arranged opposite to each other in the first direction X, and the first edge arc surface 292 and the third edge arc surface 294 are arranged opposite to each other in the second direction Y; it should be noted that the edge plane 291 is located on the side of the second edge arc surface 293 close to the foldable area S3, combined with Fig. 9 , Fig.12 and Fig.13a As shown; and the curvature of the first edge arc surface 292 gradually decreases from the second edge arc surface 293 to the edge plane 291, combined with Fig.12 , Fig.13b , Fig.13c , or combined Fig.12 , Fig.14a and Fig.14b Similarly, the curvature of the third edge arc surface 294 gradually decreases from the second edge arc surface 293 to the edge plane 291.

[0127] In the embodiment of the present disclosure, the outer surface of the first cover plate 29 is provided with a region at the edge of the foldable display device as a curved surface, Fig.12 , Figures 13b to 13d As shown, or combined Fig.12 , Figures 14a to 14cAs shown, namely: the first edge arc surface 292, the second edge arc surface 293 and the third edge arc surface 294; on the one hand, the problem of stress concentration at the edge of the first cover plate 29 can be avoided during the drop test, thereby avoiding damage to the first cover plate 29, and improving the product reliability of the first cover plate 29 and the entire foldable display device during the drop process; on the other hand, the contact area between the first cover plate 29 and the user's hand can be appropriately increased to appropriately alleviate the concentrated stress generated by the edge of the first cover plate 29 on the user's hand during the hand-holding process, thereby improving the user experience.

[0128] In addition, by setting the area in the middle of the foldable display device on the outer surface of the first cover plate 29 to be a flat surface, the Fig.12 and Fig.13a As shown, that is: edge plane 291; on the one hand, when the foldable display device is in the unfolded state, the gap generated in the middle of the back side of the foldable display device (that is: the plane where the first surface 29a of the first cover plate 29 is located) can be reduced to improve product quality; on the other hand, the support area of ​​the back side of the foldable display device can also be increased. In this way, when the back side of the foldable display device is used as a supporting surface, the problem of stress concentration in the middle of its back side can be alleviated, thereby extending the service life of the product.

[0129] In order to make the edge of the first cover plate 29 smoothly transition, the curvature of the first edge arc surface 292 and the third edge arc surface 294 needs to be gradually reduced from the second edge arc surface 293 to the edge plane 291. Fig.12 , Fig.13b and Fig.13c As shown, or combined Fig.12 , Fig.14a and Fig.14b As shown, such a design can avoid the problem of stress concentration caused by contact due to excessive difference in curvature between the first edge arc surface 292 and the third edge arc surface 294 and the edge plane 291, thereby improving the structural strength of the first cover plate 29 and extending its service life.

[0130] Optionally, the curvature of the first edge arc surface 292 at the connection with the edge plane 291 can be 0; the curvature of the third edge arc surface 294 at the connection with the edge plane 291 can be 0, further avoiding the problem of stress concentration between the first edge arc surface 292 and the third edge arc surface 294 and the edge plane 291, thereby improving the structural strength of the first cover plate 29 and extending its service life.

[0131] like Fig.12As shown, the width of the first edge arc surface 292 at the junction with the edge plane 291 is W1, the width of the first edge arc surface 292 at the junction with the second edge arc surface 293 is W2, and the ratio of W2 to W1 is 0.5 to 0.8, such as: 0.5, 0.55, 0.65, 0.7, 0.75, 0.8, etc. For example, W1 can be 4mm, and W2 can be 3mm. This design can avoid the edge from being easily damaged during the drop test and achieve a smooth transition, while also reducing the proportion of the edge arc surface, which ensures the product's self- On the one hand, it can improve the structural strength of the body, and on the other hand, it can also improve the visual effect and enhance the user experience; similarly, the width of the third edge arc surface 294 at the connection with the edge plane 291 is W3, and the width of the third edge arc surface 294 at the connection with the second edge arc surface 293 is W4, and the ratio of W4 to W3 is 0.5 to 0.8, such as: 0.5, 0.55, 0.65, 0.7, 0.75, 0.8, etc. For example, W3 can be 4mm and W4 can be 3mm; It should be noted that the widths W1, W2, W3, and W4 are the dimensions in the second direction Y.

[0132] The curvature of the second edge arc surface 293 at each location in the second direction Y is the same to reduce the difficulty of processing. It should be noted that the curvature of the first edge arc surface 292 at the connection with the second edge arc surface 293 may be the same as the curvature of the second edge arc surface 293, but is not limited to this, and may also be different, depending on the specific situation; similarly, the curvature of the third edge arc surface 294 at the connection with the second edge arc surface 293 may be the same as the curvature of the third edge arc surface 294, but is not limited to this, and may also be different, depending on the specific situation.

[0133] Combination Fig.10 , Fig.12 and Figures 13a to 13d As shown, in one embodiment of the present disclosure, the second surface 29 b of the first cover plate 29 can be a plane as a whole, which can reduce the difficulty of processing the first cover plate 29 and reduce the cost.

[0134] In another embodiment of the present disclosure, the area of ​​the second surface 29b of the first cover plate 29 opposite to the central plane 290 and the area opposite to the edge plane 291 may both be planes; Fig.11 , Fig.12 and Figures 14a to 14c As shown, the area of ​​the second surface 29b opposite to the first edge arc surface 292, the area opposite to the second edge arc surface 293, and the area opposite to the third edge arc surface 294 are all arc surfaces, that is, the portion of the first cover plate 29 close to the edge area of ​​the entire foldable display device can be bent into an arc-shaped structure as a whole.

[0135] Among them, the curvature of the area in the second surface 29b opposite to the first edge arc surface 292 is the same as the curvature of the first edge arc surface 292; the curvature of the area in the second surface 29b opposite to the second edge arc surface 293 is the same as the curvature of the second edge arc surface 293; the curvature of the area in the second surface 29b opposite to the third edge arc surface 294 is the same as the curvature of the third edge arc surface 294; but not limited to this, the curvatures of corresponding parts may also be different, depending on the specific situation.

[0136] It should be noted that, when the portion of the first cover plate 29 close to the edge area of ​​the entire foldable display device is bent as a whole into an arc-shaped structure, the portion of the first display panel 10 close to the edge area of ​​the entire foldable display device can also be bent together with the edge portion of the first cover plate 29 to form an arc-shaped structure, which can facilitate the realization of full-screen display.

[0137] In the embodiment of the present disclosure, the position between the first cover plate 29 and the first display panel 10 can refer to Fig. 9 , Fig.12 class Fig.15 As shown, specifically, the first display panel 10 has a display area ( Fig.15 The area enclosed by the double-dashed line in the middle) and the non-display area ( Fig.15 The display area has a first boundary L1 and a second boundary L2 opposite to each other in the second direction Y, and both the first boundary L1 and the second boundary L2 extend in the first direction X; the boundary of the first edge arc surface 292 connected to the center plane 290 is a third boundary L3, and the third boundary L3 intersects with the first boundary L1, and the intersection point is the first intersection point K1; the boundary of the third edge arc surface 294 connected to the center plane 290 is a fourth boundary L4, and the fourth boundary L4 intersects with the second boundary L2, and the intersection point is the second intersection point K2.

[0138] Among them, the ratio of the length of the line segment in the first boundary L1 located at the first intersection K1 close to the second edge arc surface 293 to the length of the line segment in the first boundary L1 located at the first intersection K1 close to the edge plane 291 is 0.2 to 0.5, for example: 0.2, 0.3, 0.4, 0.5, etc. This design can reduce the impact of the cover on the display while achieving smooth processing; similarly, the ratio of the length of the line segment in the second boundary L2 located at the second intersection K2 close to the second edge arc surface 293 to the length of the line segment in the second boundary L2 located at the second intersection K2 close to the edge plane 291 is 0.2 to 0.5, for example: 0.2, 0.3, 0.4, 0.5, etc.

[0139] It should be noted that, in the above-mentioned embodiment, the first display panel 10 may include a display portion 10a, a binding portion 10b located at the back of the display portion 10a, and a bending portion 10c connecting the display portion 10a and the binding portion 10b; wherein, Figure 2 , Figure 4 , Fig. 9 , Fig.12 and Fig.15 As shown, a part of the orthographic projection of the binding portion 10b on the reference plane is located within the orthographic projection of the third edge arc surface 294 on the reference plane, and the other part is located within the orthographic projection of the center plane 290 on the reference plane. It should be understood that the reference plane mentioned here is a plane parallel to the center plane 290.

[0140] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A cover plate for a foldable display device, wherein the foldable display device has a first area, a second area, and a foldable area connecting the first area and the second area, wherein: The foldable display device comprises a first display panel located in the first area, and the cover plate is located in the first area and is arranged on the display side of the first display panel; characterized in that: The surface of the cover plate away from the first display panel is the first surface; the first surface includes a central plane and an edge plane, a first edge curved surface, a second edge curved surface and a third edge curved surface that surround the central plane and are sequentially connected end to end; the edge plane and the second edge curved surface are arranged opposite to each other in a first direction, the first edge curved surface and the third edge curved surface are arranged opposite to each other in a second direction, and the second direction is perpendicular to the first direction; The edge plane is located on a side of the second edge arc surface close to the foldable area; and the curvatures of the first edge arc surface and the third edge arc surface gradually decrease from the second edge arc surface to the edge plane.

2. The cover plate according to claim 1, characterized in that: The curvature of the first edge arc surface at the junction with the edge plane is 0; The curvature of the third edge arc surface at a portion where it meets the edge plane is 0.

3. The cover plate according to claim 2, characterized in that: The width of the first edge arc surface at the junction with the edge plane is W1, the width of the first edge arc surface at the junction with the second edge arc surface is W2, and the ratio of W2 to W1 is 0.5 to 0.8; The width of the third edge arc surface at the edge plane is W3, the width of the third edge arc surface at the second edge arc surface is W4, and the ratio of W4 to W3 is 0.5 to 0.8; The width is the dimension in the second direction.

4. The cover plate according to claim 1, characterized in that: The curvature of the second edge arc surface at each location in the second direction is the same.

5. The cover plate according to any one of claims 1 to 4, characterized in that: A surface of the cover plate close to the first display panel is a second surface, wherein the second surface is a plane.

6. The cover plate according to any one of claims 1 to 4, characterized in that: The surface of the cover plate close to the first display panel is the second surface, wherein: The area of ​​the second surface opposite to the central plane and the area opposite to the edge plane are both planes; The area of ​​the second surface opposite to the first edge arc surface, the area opposite to the second edge arc surface, and the area opposite to the third edge arc surface are all arc surfaces.

7. The cover plate according to claim 6, characterized in that: The curvature of the area of ​​the second surface opposite to the first edge arc surface is the same as the curvature of the first edge arc surface; The curvature of the area of ​​the second surface opposite to the second edge arc surface is the same as the curvature of the second edge arc surface; The curvature of a region of the second surface opposite to the third edge arc surface is the same as the curvature of the third edge arc surface.

8. A foldable display device, characterized in that: The foldable display device has a first area, a second area and a foldable area connected between the first area and the second area, wherein the foldable display device includes a first display panel and a first cover plate located in the first area, the first cover plate is arranged on the display side of the first display panel, and the first cover plate is the cover plate described in any one of claims 1 to 7.

9. The foldable display device according to claim 8, characterized in that: The first display panel has a display area and a non-display area surrounding the display area, the display area has a first boundary and a second boundary opposite to each other in the second direction, and both the first boundary and the second boundary extend in the first direction; The boundary of the first edge arc surface connected to the central plane is a third boundary, and the third boundary intersects with the first boundary, and the intersection point is a first intersection point; The boundary of the third edge arc surface that is connected to the central plane is a fourth boundary, and the fourth boundary intersects with the second boundary, and their intersection is a second intersection point; wherein, The ratio of the length of the line segment in the first boundary located at the first intersection close to the second edge arc surface to the length of the line segment in the first boundary located at the first intersection close to the edge plane is 0.2 to 0.5; A ratio of a length of a line segment in the second boundary located at the second intersection point close to the second edge arc surface to a length of a line segment in the second boundary located at the second intersection point close to the edge plane is 0.2 to 0.

5.

10. The foldable display device according to claim 9, characterized in that: The first display panel is flexible; the first display panel includes a display portion, a binding portion located at the back side of the display portion, and a bending portion connecting the display portion and the binding portion; the first cover plate is provided on the display side of the display portion, and the display portion includes the display area and the non-display area; Among them, a part of the orthographic projection of the binding part on the reference plane is located within the orthographic projection of the third edge arc surface on the reference plane, and the other part is located within the orthographic projection of the center plane on the reference plane, and the reference plane is a plane parallel to the center plane.

11. The foldable display device according to claim 8, characterized in that: The foldable display device further includes a second display panel and a second cover plate located in the first area, the second area, and the foldable area; The second display panel and the second cover plate are flexible, a side of the second display panel away from the first display panel is a display side, the second cover plate is located on the display side of the second display panel, and an outer contour of the second cover plate exceeds an outer contour of the second display panel.

Images