Flexible cover plate, flexible display panel and foldable display device

Abstract

The invention relates to the technical field of display, and discloses a flexible cover plate, a flexible display panel and a foldable display device. The flexible cover plate is provided with a bending area and a non-bending area which are arranged in the first direction, and the flexible cover plate comprises an unequal-thickness ultra-thin glass layer, a flexible layer and a reinforcing layer. The unequal-thickness ultra-thin glass layer is provided with a sunken structure, and at least part of the sunken structure is located in the bending area; the flexible layer is at least arranged in the sunken structure; the reinforcing layer is at least arranged in the concave structure, the modulus of the reinforcing layer is larger than that of the flexible layer, and the modulus of the reinforcing layer is smaller than that of the unequal-thickness ultra-thin glass layer. The flexible cover plate is easy to bend in the bending area, and is high in impact resistance and spherical object falling performance.

Description

Technical Field

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

[0002] In order to ensure the bending performance of the foldable display device, the cover plate of the foldable display device adopts a material with a low modulus, which reduces the protective effect of the cover plate on the display substrate; however, the cover plate of the foldable display device adopts a material with a high modulus, which makes the stress of the cover plate larger after bending, affecting the display effect and service life of the display substrate, and easily generating creases. Therefore, the flexibility and hardness of the cover plate of the current foldable display device are not compatible.

[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 overcome the above-mentioned deficiencies of the prior art and to provide a flexible cover plate, a flexible display panel including the flexible cover plate, and a foldable display device including the flexible display panel.

[0005] According to one aspect of the present disclosure, there is provided a flexible cover having a bending area and a non-bending area arranged along a first direction, the flexible cover comprising:

[0006] Ultra-thin glass layers of unequal thickness, wherein a concave structure is provided on the ultra-thin glass layers of unequal thickness, and at least a portion of the concave structure is located in the bending area;

[0007] A flexible layer, at least disposed in the recessed structure;

[0008] The reinforcing layer is at least arranged in the recessed structure, the modulus of the reinforcing layer is greater than the modulus of the flexible layer, and the modulus of the reinforcing layer is less than the modulus of the ultra-thin glass layers of unequal thickness.

[0009] In an exemplary embodiment of the present disclosure, a groove is provided on the reinforcement layer, and the groove extends along a second direction, and the second direction is perpendicular to the first direction.

[0010] In an exemplary embodiment of the present disclosure, the groove is arranged on a side of the reinforcement layer close to the bottom wall of the recessed structure, or the groove is arranged on a side of the reinforcement layer away from the bottom wall of the recessed structure.

[0011] In an exemplary embodiment of the present disclosure, the depth of the groove is less than or equal to 50% of the thickness of the reinforcement layer.

[0012] In an exemplary embodiment of the present disclosure, the groove arranged on the side of the reinforcing layer close to the bottom wall of the recessed structure is a first groove, and the groove arranged on the side of the reinforcing layer away from the bottom wall of the recessed structure is a second groove. The first groove and the second groove are staggered, or the first groove and the second groove are opposite to each other.

[0013] In an exemplary embodiment of the present disclosure, the sum of the depth of the first groove and the depth of the second groove is less than or equal to 50% of the thickness of the reinforcement layer.

[0014] In an exemplary embodiment of the present disclosure, the ratio of the absolute value of the difference between the refractive index of the flexible layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.5%, and the ratio of the absolute value of the difference between the refractive index of the strengthening layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.5%.

[0015] In an exemplary embodiment of the present disclosure, the ratio of the absolute value of the difference between the refractive index of the flexible layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.3%, and the ratio of the absolute value of the difference between the refractive index of the strengthening layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.3%.

[0016] In an exemplary embodiment of the present disclosure, the modulus of the reinforcement layer is greater than or equal to 0.1 GPa and less than or equal to 6 GPa, and the modulus of the flexible layer is greater than or equal to 0.01 GPa and less than or equal to 1 GPa.

[0017] In an exemplary embodiment of the present disclosure, a ratio of a total thickness of the reinforcement layer to a depth of the recessed structure is greater than or equal to 0.2 and less than or equal to 0.7.

[0018] In an exemplary embodiment of the present disclosure, a ratio of a total thickness of the reinforcement layer to a depth of the recessed structure is greater than or equal to 0.3 and less than or equal to 0.5.

[0019] In an exemplary embodiment of the present disclosure, in the second direction, the ratio of the length of the reinforcing layer to the length of the recessed structure is greater than or equal to 0.75 and less than or equal to 1; in the first direction, the ratio of the width of the reinforcing layer to the width of the recessed structure is greater than or equal to 0.75 and less than or equal to 1, and the first direction intersects with the second direction.

[0020] In an exemplary embodiment of the present disclosure, the reinforcement layer includes a first part, a second part and a third part connected in sequence along the first direction, the thickness of the first part is greater than the thickness of the second part, and the thickness of the third part is greater than the thickness of the second part.

[0021] In an exemplary embodiment of the present disclosure, in the first direction, the width of the first portion is less than or equal to 50% of the width of the second portion, and the width of the third portion is less than or equal to 50% of the width of the second portion.

[0022] In an exemplary embodiment of the present disclosure, the recessed structure includes a first side wall, a first transition surface, a bottom wall, a second transition surface and a second side wall connected in sequence; the bottom wall is connected to the first transition surface to form a first connection portion, and the first connection portion is arranged opposite to the first portion; the bottom wall is connected to the second transition surface to form a second connection portion, and the second connection portion is arranged opposite to the third portion.

[0023] In an exemplary embodiment of the present disclosure, the ultra-thin glass layer of unequal thickness has two surfaces arranged opposite to each other; both surfaces are provided with the recessed structure, and the recessed structures of the two surfaces are arranged opposite to each other, or the recessed structure is provided on only one of the surfaces.

[0024] In an exemplary embodiment of the present disclosure, the flexible layer and the reinforcing layer are disposed in the recessed structures on the two surfaces;

[0025] Alternatively, the two relatively arranged surfaces of the ultra-thin glass layers of unequal thickness are the first surface and the second surface, the recessed structure arranged on the first surface is the first recessed structure, the recessed structure arranged on the second surface is the second recessed structure, only the flexible layer is arranged in the first recessed structure, and the flexible layer and the reinforcing layer are arranged in the second recessed structure.

[0026] In an exemplary embodiment of the present disclosure, within one of the recessed structures, the flexible layer is provided as at least two layers, the reinforcing layer is provided as at least one layer, and the reinforcing layer and the flexible layer are alternately provided.

[0027] In an exemplary embodiment of the present disclosure, the flexible layer located at the outermost layer extends outside the recessed structure.

[0028] In an exemplary embodiment of the present disclosure, in one of the recessed structures, the reinforcement layer is provided as two layers, the flexible layer is provided as one layer, and at least one reinforcement layer is located on a side of the flexible layer away from the ultra-thin glass layers of unequal thickness.

[0029] In an exemplary embodiment of the present disclosure, in one of the recessed structures, the flexible layer is provided as one layer, the reinforcing layer is provided as one layer, and the reinforcing layer is located on a side of the flexible layer away from the ultra-thin glass layers of unequal thicknesses.

[0030] According to another aspect of the present disclosure, there is provided a flexible display panel, comprising:

[0031] Display substrate;

[0032] The flexible cover plate is any one of the flexible cover plates described above, and the flexible cover plate is arranged on the light output side of the display substrate.

[0033] According to another aspect of the present disclosure, a foldable display device is provided, comprising the flexible display panel described above.

[0034] The flexible cover plate disclosed in the present invention, on the one hand, reduces the hardness of the ultra-thin glass layers of unequal thickness in the bending area by arranging a recessed structure on the ultra-thin glass layers of unequal thickness in the bending area, so that the ultra-thin glass layers of unequal thickness can be easily bent in the bending area; on the other hand, the modulus of the reinforcing layer is greater than the modulus of the flexible layer, so that the reinforcing layer can improve the impact resistance (for example, pen and ball drops) of the ultra-thin glass layers of unequal thickness in the bending area, and the flexibility of the reinforcing layer is better than that of the ultra-thin glass layers of unequal thickness, which is beneficial to the bending of the flexible cover plate; and the flexible layer can ensure the bending performance of the ultra-thin glass layers of unequal thickness in the bending area.

[0035] 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

[0036] 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.

[0037] Figure 1 It is a schematic structural diagram of an exemplary embodiment of the flexible cover disclosed in the present invention.

[0038] Figure 2 for Figure 1 A schematic cross-sectional view of a first exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0039] Figure 3 for Figure 1 A schematic cross-sectional view of a second exemplary embodiment of ultra-thin glass layers of unequal thickness in a flexible cover.

[0040] Figure 4 for Figure 3 A partial enlarged schematic diagram of the part indicated by I.

[0041] Figure 5 for Figure 3 Schematic diagram of the structure of the middle reinforcement layer.

[0042] Figure 6 FIG. 1 is a schematic structural diagram of a second exemplary embodiment of a reinforcement layer.

[0043] Figure 7 FIG. 1 is a schematic structural diagram of a third exemplary embodiment of a reinforcement layer.

[0044] Figure 8 for Figure 1 A schematic structural diagram of a third exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0045] Fig. 9 for Figure 8 Schematic diagram of the structure of the middle reinforcement layer.

[0046] Fig.10 FIG. 4 is a schematic structural diagram of a fifth exemplary embodiment of a reinforcement layer.

[0047] Fig.11 FIG. 1 is a schematic structural diagram of a sixth exemplary embodiment of a reinforcement layer.

[0048] Fig.12 FIG. 1 is a schematic structural diagram of a seventh exemplary embodiment of a reinforcement layer.

[0049] Fig.13 for Figure 9-12 Schematic diagram of the top view structure of the middle reinforcement layer.

[0050] Fig.14 for Figure 1 A schematic structural diagram of a fourth exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0051] Fig.15 for Figure 1 A schematic structural diagram of a fifth exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0052] Fig.16 for Figure 1 A schematic structural diagram of a sixth exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0053] Fig.17 for Figure 1 A schematic structural diagram of the seventh exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0054] Fig.18 for Figure 1 A schematic structural diagram of an eighth exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0055] Fig.19 for Figure 1 A schematic structural diagram of a ninth exemplary embodiment of ultra-thin glass layers of unequal thickness in a medium-flexible cover.

[0056] Fig. 20 It is a schematic structural diagram of an exemplary implementation of a flexible display panel disclosed in the present invention.

[0057] Description of reference numerals:

[0058] 1. Ultra-thin glass layers of unequal thickness; 1a. first surface; 1b. second surface; 11. recessed structure; 11a. first recessed structure; 11b. second recessed structure; 111. first side wall; 112. first transition surface; 112-3. first connecting portion; 113. bottom wall; 113-4. second connecting portion; 114. second transition surface; 115. second side wall;

[0059] 2. Flexible layer;

[0060] 3. reinforcing layer; 31. first part; 32. second part; 33. third part; 34. groove; 34a. first groove; 34a1. first groove side wall; 34b. second groove; 34b1. second groove side wall;

[0061] 10. Flexible cover;

[0062] 20. Display substrate; 201. Base substrate; 202. Driving backplane; 203. Light emitting device;

[0063] 30. Touch control substrate;

[0064] X, first direction; Y, second direction; Z, thickness direction; ZW, bending area; FZW, non-bending area. DETAILED DESCRIPTION

[0065] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0066] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0067] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0068] In this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. "And / or" is just a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0069] The exemplary embodiment of the present disclosure provides a flexible cover 10, referring to Figure 1-Figure 19 As shown, the flexible cover plate 10 has a bending area ZW and a non-bending area FZW arranged along a first direction X, and the flexible cover plate 10 may include an ultra-thin glass layer 1 of unequal thickness, a flexible layer 2 and a reinforcing layer 3; a recessed structure 11 is provided on the ultra-thin glass layer 1 of unequal thickness, and at least a part of the recessed structure 11 is located in the bending area ZW; the flexible layer 2 is at least provided in the recessed structure 11; the reinforcing layer 3 is at least provided in the recessed structure 11, and the modulus of the reinforcing layer 3 is greater than the modulus of the flexible layer 2, and the modulus of the reinforcing layer 3 is less than the modulus of the ultra-thin glass layer 1 of unequal thickness.

[0070] The flexible cover plate 10 disclosed in the present invention, on the one hand, reduces the hardness of the ultra-thin glass layer 1 of unequal thickness in the bending area ZW by setting a recessed structure 11 on the ultra-thin glass layer 1 of unequal thickness in the bending area ZW, so that the ultra-thin glass layer 1 of unequal thickness can be easily bent in the bending area ZW; on the other hand, the modulus of the reinforcing layer 3 is greater than the modulus of the flexible layer 2, so that the reinforcing layer 3 can improve the impact resistance (for example, pen and ball falling) of the ultra-thin glass layer 1 of unequal thickness in the bending area ZW, and the flexibility of the reinforcing layer 3 is better than that of the ultra-thin glass layer 1 of unequal thickness, which is beneficial to the bending of the flexible cover plate 10; and the flexible layer 2 can ensure the bending performance of the ultra-thin glass layer 1 of unequal thickness in the bending area ZW.

[0071] The flexible cover plate 10 can be bent, and therefore, the flexible cover plate 10 has a bending area ZW, and the flexible cover plate 10 is bent in the bending area ZW. Figure 1 As shown, the flexible cover plate 10 may include two non-bending areas FZW and one bending area ZW, the two non-bending areas FZW and one bending area ZW are arranged along the first direction X, and the bending area ZW is connected between the two non-bending areas FZW. Of course, in some other example embodiments of the present disclosure, the non-bending areas FZW and the bending areas ZW may be set to more as needed, which are not described one by one here.

[0072] The flexible cover 10 can be set to a single-layer structure, in which case the flexible cover 10 can include a layer of inorganic material; the flexible cover 10 can also be set to a multi-layer structure, in which case the flexible cover 10 can include at least one layer of inorganic material and at least one layer of organic material, or at least two layers of inorganic material; the inorganic material layer can be ultra-thin glass (Ultra Thin Glass, UTG), ultra-thin glass of unequal thickness (Ultra Flexible Glass, UFG), etc.; the organic material can be one or more of polyimide (PI), polyethylene terephthalate, polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), etc.

[0073] In this example embodiment, the flexible cover plate 10 may include a layer of ultra-thin glass layer 1 of unequal thickness, the thickness of the ultra-thin glass layer 1 of unequal thickness is greater than 30 μm and less than or equal to 500 μm, for example, the thickness of the ultra-thin glass layer 1 of unequal thickness may be 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 170 μm, 200 μm, 230 μm, 250 μm, 280 μm, 300 μm, 320 μm, 350 μm, 370 μm, 400 μm, 430 μm, 450 μm, 480 μm, etc. The ultra-thin glass layer 1 of unequal thickness may be produced by conventional processes such as overflow method, down-draw method, and casting method.

[0074] Reference Figure 2 As shown, a recessed structure 11 is provided on the ultra-thin glass layer 1 of unequal thickness. For example, a portion of the ultra-thin glass layer 1 of unequal thickness can be etched by a thinning process such as photolithography to form the recessed structure 11. The thickness of the ultra-thin glass layer 1 of unequal thickness remaining at the recessed structure 11 is greater than or equal to 30 μm and less than or equal to 470 μm. For example, the thickness of the ultra-thin glass layer 1 of unequal thickness remaining at the recessed structure 11 can be 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 170 μm, 200 μm, 230 μm, 250 μm, 280 μm, 300 μm, 320 μm, 350 μm, 370 μm, 400 μm, 430 μm, 450 μm, and the like.

[0075] At least part of the recessed structure 11 is located in the bending area ZW. For example, the recessed structure 11 may be entirely located in the bending area ZW, and the recessed structure 11 may be slightly smaller than the bending area ZW; the recessed structure 11 may be entirely located in the bending area ZW, and the recessed structure 11 may basically occupy the bending area ZW; or part of the recessed structure 11 may be located in the bending area ZW, and the other part of the recessed structure 11 may be located in the non-bending area FZW.

[0076] Reference Figure 1 As shown, the recessed structure 11 extends along the second direction Y, and the second direction Y is perpendicular to the first direction X, or it can be said that the second direction Y is perpendicular to the bending direction of the flexible cover plate 10; the recessed structure 11 can be a through groove penetrating the ultra-thin glass layers 1 of unequal thickness in the second direction Y, and the recessed structure 11 can also be a blind groove that does not penetrate the ultra-thin glass layers 1 of unequal thickness at one end or both ends.

[0077] Reference Figure 2 As shown, the recessed structure 11 may be configured as a rectangular groove, that is, the cross-sectional shape of the recessed structure 11 perpendicular to the second direction Y may be a rectangle.

[0078] Reference Figure 3As shown, the recessed structure 11 can be set as a "U"-shaped groove, that is, the cross-sectional shape of the recessed structure 11 perpendicular to the second direction Y can be a "U" shape. Specifically, the recessed structure 11 may include a first side wall 111, a first transition surface 112, a bottom wall 113, a second transition surface 114 and a second side wall 115 connected in sequence. The first transition surface 112 and the second transition surface 114 can be set as arc surfaces, so that there is a smooth transition between the first side wall 111 and the bottom wall 113, and there is also a smooth transition between the bottom wall 113 and the second side wall 115. In addition, the stress concentration at the corner portion caused by the formation of a right angle, an acute angle or an obtuse angle structure is avoided, so that the corner portion of the recessed structure 11 is not easy to crack, so as to ensure the strength of the ultra-thin glass layer 1 of unequal thickness. In addition, the first transition surface 112 and the second transition surface 114 may include a plane and curved surfaces connected to both sides of the plane, which can also enable a smooth transition between the first side wall 111 and the bottom wall 113, and a smooth transition between the bottom wall 113 and the second side wall 115, so as to ensure the strength of the ultra-thin glass layers 1 of unequal thickness.

[0079] In addition, in some other exemplary embodiments of the present disclosure, the sidewalls of the recessed structure 11 can be set to be stepped, that is, the first sidewall 111 and the second sidewall 115 can be set to be stepped surfaces, so that the recessed structure 11 forms a structure with a gradually expanding opening. The stepped recessed structure 11 can be formed by multiple thinning processes. The recessed structure 11 can also be set to be multiple at intervals, and the multiple recessed structures 11 are arranged in the bending area ZW along the second direction Y.

[0080] Of course, in some other example embodiments of the present disclosure, the flexible cover 10 may include two or more layers of ultra-thin glass layers 1 of unequal thickness. In this case, a recessed structure 11 is provided on at least one layer of ultra-thin glass layers 1 of unequal thickness, that is, a recessed structure 11 may be provided on one layer of ultra-thin glass layers 1 of unequal thickness, or a recessed structure 11 may be provided on two or more layers of ultra-thin glass layers 1 of unequal thickness. The specific structure of the recessed structure 11 has been described in detail above, so it will not be repeated here. By providing a recessed structure 11 on the ultra-thin glass layers 1 of unequal thickness in the bending area ZW, the hardness of the ultra-thin glass layers 1 of unequal thickness in the bending area ZW is reduced, so that the ultra-thin glass layers 1 of unequal thickness can be easily bent in the bending area ZW.

[0081] In this example embodiment, a flexible layer 2 is provided at least in the recessed structure 11, a reinforcing layer 3 is provided at least in the recessed structure 11, and the modulus of the reinforcing layer 3 is greater than the modulus of the flexible layer 2, and the modulus of the reinforcing layer 3 is less than the modulus of the ultra-thin glass layers 1 of unequal thickness, so that the reinforcing layer 3 can improve the impact resistance (for example, pen and ball falling) of the ultra-thin glass layers 1 of unequal thickness in the bending area ZW, and the flexibility of the reinforcing layer 3 is better than that of the ultra-thin glass layers 1 of unequal thickness, which is beneficial to the bending of the flexible cover plate 10; and the flexible layer 2 can ensure the bending performance of the ultra-thin glass layers 1 of unequal thickness in the bending area ZW.

[0082] Specifically, the modulus of the reinforcement layer 3 is greater than or equal to 0.1 Gpa and less than or equal to 6 Gpa. For example, the modulus of the reinforcement layer 3 may be 0.3 Gpa, 0.5 Gpa, 0.8 Gpa, 1 Gpa, 1.2 Gpa, 1.5 Gpa, 1.7 Gpa, 2 Gpa, 2.3 Gpa, 2.5 Gpa, 2.8 Gpa, 3 Gpa, 3.2 Gpa, 3.5 Gpa, 3.7 Gpa, 4 Gpa, 4.3 Gpa, 4.5 Gpa, 4.8 Gpa, 5 Gpa, 5.2 Gpa, 5.5 Gpa, 5.7 Gpa and the like.

[0083] The modulus of the flexible layer 2 is greater than or equal to 0.01 Gpa and less than or equal to 1 Gpa. For example, the modulus of the flexible layer 2 can be 0.03 Gpa, 0.05 Gpa, 0.08 Gpa, 0.1 Gpa, 0.12 Gpa, 0.15 Gpa, 0.17 Gpa, 0.2 Gpa, 0.23 Gpa, 0.25 Gpa, 0.28 Gpa, 0.3 Gpa, 0.32 Gpa, 0.35 Gpa, 0.37 Gpa, 0.4 Gpa, 0.43 Gpa, 0.45Gpa, 0.48Gpa, 0.5Gpa, 0.52Gpa, 0.55Gpa, 0.57Gpa, 0.6Gpa, 0.63Gpa, 0.65Gpa, 0.68Gpa, 0.7Gpa, 0 .72Gpa, 0.75Gpa, 0.77Gpa, 0.8Gpa, 0.83Gpa, 0.85Gpa, 0.88Gpa, 0.9Gpa, 0.92Gpa, 0.95Gpa, 0.97Gpa, etc.

[0084] In this exemplary embodiment, the ratio of the absolute value of the difference between the refractive index λ2 of the flexible layer 2 and the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness to the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness is less than or equal to 0.5%, and the specific formula is |λ2-λ1| / λ1≤0.5%, that is, the refractive index of the flexible layer 2 may be larger than the refractive index of the ultra-thin glass layer 1 of unequal thickness, or the refractive index of the flexible layer 2 may be smaller than the refractive index of the ultra-thin glass layer 1 of unequal thickness. For example, the ratio of the absolute value of the difference between the refractive index λ2 of the flexible layer 2 and the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness to the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness may be 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, etc.

[0085] The ratio of the absolute value of the difference between the refractive index λ3 of the strengthening layer 3 and the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness to the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness is less than or equal to 0.5%, and the specific formula is |λ3-λ1| / λ1≤0.5%, that is, the refractive index of the strengthening layer 3 may be larger than the refractive index of the ultra-thin glass layer 1 of unequal thickness, or the refractive index of the strengthening layer 3 may be smaller than the refractive index of the ultra-thin glass layer 1 of unequal thickness. For example, the ratio of the absolute value of the difference between the refractive index λ3 of the strengthening layer 3 and the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness to the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness may be 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, etc.

[0086] By such arrangement, the refractive index of the flexible layer 2 is slightly different from that of the ultra-thin glass layers 1 of unequal thicknesses, thereby avoiding the contour of the flexible layer 2 due to the difference in refractive index between the edge of the flexible layer 2 and the ultra-thin glass layers 1 of unequal thicknesses, thereby ensuring the display effect; the refractive index of the strengthening layer 3 is also slightly different from that of the ultra-thin glass layers 1 of unequal thicknesses, and similarly, avoiding the contour of the strengthening layer 3 due to the difference in refractive index between the edge of the strengthening layer 3 and the ultra-thin glass layers 1 of unequal thicknesses, thereby ensuring the display effect.

[0087] Optionally, the ratio of the absolute value of the difference between the refractive index λ2 of the flexible layer 2 and the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness to the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness is less than or equal to 0.3%, and the specific formula is |λ2-λ1| / λ1≤0.3%; the ratio of the absolute value of the difference between the refractive index λ3 of the strengthening layer 3 and the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness to the refractive index λ1 of the ultra-thin glass layer 1 of unequal thickness is less than or equal to 0.3%, and the specific formula is |λ3-λ1| / λ1≤0.3%.

[0088] Such an arrangement makes the refractive index of the flexible layer 2 less different from that of the ultra-thin glass layers 1 of unequal thicknesses, thereby avoiding the outline of the flexible layer 2 due to the difference in refractive index between the edge of the flexible layer 2 and the ultra-thin glass layers 1 of unequal thicknesses, thereby ensuring the display effect; the refractive index of the strengthening layer 3 is also less different from that of the ultra-thin glass layers 1 of unequal thicknesses. Similarly, the outline of the strengthening layer 3 is avoided due to the difference in refractive index between the edge of the strengthening layer 3 and the ultra-thin glass layers 1 of unequal thicknesses, thereby ensuring the display effect.

[0089] The material of the flexible layer 2 may be an organic material or an inorganic material. The organic material may include polyimide (PI), polyethylene terephthalate, polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), polyurethane, polyaramid, acrylic, polyacrylate, polyvinylidene chloride, polyvinylidene fluoride (PVDF), polystyrene, ethylene vinyl alcohol copolymer, polyether sulfone (PES), polyetherimide (PEI), polyphenylene sulfide (PPS), polyallyl ester, triacetate film (TAC), cellulose acetate propionate (CAP), etc. The inorganic material may include flexible glass.

[0090] The material of the reinforcing layer 3 may be an organic material or an inorganic material. The organic material may include polyimide (PI), polyethylene terephthalate, polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), polyurethane, polyaramid, acrylic, polyacrylate, polyvinylidene chloride, polyvinylidene fluoride (PVDF), polystyrene, ethylene vinyl alcohol copolymer, polyether sulfone (PES), polyetherimide (PEI), polyphenylene sulfide (PPS), polyallyl ester, triacetate film (TAC), cellulose acetate propionate (CAP), etc. The inorganic material may include flexible glass.

[0091] The flexible layer 2 and the reinforcing layer 3 can be formed by coating and dispensing processes, and the reinforcing layer 3 can be a finished film, which is fixed on the ultra-thin glass layer 1 of unequal thickness by a laminating process. The above-mentioned process methods can be used on a flexible cover plate 10.

[0092] In this example embodiment, the ratio of the total thickness of the reinforcement layer 3 to the depth of the recessed structure 11 is greater than or equal to 0.2 and less than or equal to 0.7. For example, the ratio of the total thickness of the reinforcement layer 3 to the depth of the recessed structure 11 may be 0.23, 0.25, 0.28, 0.3, 0.32, 0.35, 0.37, 0.4, 0.43, 0.45, 0.48, 0.5, 0.52, 0.55, 0.57, 0.6, 0.63, 0.65, 0.68, and the like.

[0093] If the ratio of the total thickness of the reinforcing layer 3 to the depth of the recessed structure 11 is too small, the total thickness of the reinforcing layer 3 is too small, and the reinforcing effect of the reinforcing layer 3 is not obvious. If the ratio of the total thickness of the reinforcing layer 3 to the depth of the recessed structure 11 is too large, the total thickness of the reinforcing layer 3 is too large, and the strength is too large, which is not conducive to bending.

[0094] The above numerical range not only ensures the strengthening effect of the reinforcing layer 3, but also ensures the bending effect of the flexible cover plate 10 in the bending area ZW.

[0095] Optionally, the ratio of the total thickness of the reinforcing layer 3 to the depth of the recessed structure 11 is greater than or equal to 0.3 and less than or equal to 0.5, so as to further ensure the reinforcing effect of the reinforcing layer 3 and the bending effect of the flexible cover plate 10 in the bending area ZW.

[0096] It should be noted that, in the thickness direction Z of the unequal thickness ultra-thin glass layer 1, when the reinforcing layer 3 is provided as one layer, the total thickness of the reinforcing layer 3 of course refers to the thickness of one layer of the reinforcing layer 3; in the thickness direction Z of the unequal thickness ultra-thin glass layer 1, when the reinforcing layer 3 is provided as two or more layers, the total thickness of the reinforcing layer 3 of course refers to the thickness of two or more layers of the reinforcing layer 3. Moreover, in the case where the thickness of the reinforcing layer 3 is different at different locations, the ratio of the total thickness of the reinforcing layer 3 at different locations to the depth of the recessed structure 11 may be different, as long as it is within the above range.

[0097] Reference Figure 2 As shown, the reinforcement layer 3 can be set as a flat plate structure, that is, the thickness of the reinforcement layer 3 is basically the same at all locations.

[0098] Reference Figure 8-Figure 13 As shown, a groove 34 is provided on the reinforcing layer 3, and the groove 34 extends along the second direction Y, and the second direction Y is perpendicular to the first direction X, that is, the extension direction of the groove 34 is perpendicular to the bending direction of the flexible cover plate 10. The groove 34 can increase the flexibility of the reinforcing layer 3, so that the reinforcing layer 3 is more conducive to bending, and the stress after bending is smaller; the side wall of the groove 34 can ensure the strength of the reinforcing layer 3, so that the reinforcing layer 3 has a better reinforcement effect.

[0099] The groove 34 may be provided on one side of the reinforcing layer 3. Figure 8 As shown, the groove 34 can be arranged on the side of the reinforcing layer 3 away from the bottom wall 113 of the recessed structure 11. Of course, in some other exemplary embodiments of the present disclosure, the groove 34 can also be arranged on the side of the reinforcing layer 3 close to the bottom wall 113 of the recessed structure 11;

[0100] The depth of the groove 34 is less than or equal to 50% of the thickness of the reinforcement layer 3. For example, the depth of the groove 34 can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% and so on of the thickness of the reinforcement layer 3.

[0101] If the depth of the groove 34 is too large, the impact resistance of the reinforcing layer 3 is lost; therefore, the above numerical range enables the reinforcing layer 3 to have both flexibility and impact resistance.

[0102] At least two grooves 34 may be provided. In the first direction X, the ratio of the total width of the grooves 34 to the width of the reinforcing layer 3 is greater than or equal to 0.2 and less than or equal to 0.7. For example, the ratio of the total width of the grooves 34 to the width of the reinforcing layer 3 may be 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, etc.

[0103] If the ratio of the total width of the groove 34 to the width of the reinforcing layer 3 is too small, the groove 34 has little effect on increasing the flexibility of the reinforcing layer 3; if the ratio of the total width of the groove 34 to the width of the reinforcing layer 3 is too large, the strength of the reinforcing layer 3 cannot be guaranteed.

[0104] The above numerical range not only ensures that the flexibility of the reinforcing layer 3 can be increased through the groove 34, making the reinforcing layer 3 more conducive to bending and having less stress after bending; but also ensures the strength of the reinforcing layer 3, so that the reinforcing layer 3 has a better reinforcement effect.

[0105] Reference Fig. 9 , Fig.11 and Fig.12 As shown, the groove 34 may be a rectangular groove, that is, the shape of the cross section of the groove 34 perpendicular to the second direction Y may be a rectangle. Fig.10 As shown, the groove 34 may be an arc groove, that is, the shape of the cross section of the groove 34 perpendicular to the second direction Y may be semicircular, less semicircular, semi-elliptical, less semi-elliptical, etc. Of course, the groove 34 may also be other shapes, which are not described here one by one.

[0106] In addition, in some other exemplary embodiments of the present disclosure, referring to Fig.11 and Fig.12 As shown, the groove 34 can be arranged on both sides of the reinforcing layer 3. Specifically, the groove 34 arranged on the side of the reinforcing layer 3 close to the bottom wall 113 of the recessed structure 11 is a first groove 34a, and the groove 34 arranged on the side of the reinforcing layer 3 away from the bottom wall 113 of the recessed structure 11 is a second groove 34b. Fig.12As shown, the first groove 34a and the second groove 34b can be arranged in a staggered manner, that is, the first groove 34a is arranged opposite to the second groove side wall 34b1 between two adjacent second grooves 34b, and the second groove 34b is arranged opposite to the first groove side wall 34a1 between two adjacent first grooves 34a. In addition, according to the difference in the width of the first groove 34a and the width of the second groove 34b and the difference in the width of the first groove side wall 34a1 and the width of the second groove side wall 34b1, the first groove 34a can be arranged opposite to a part of the second groove 34b.

[0107] Reference Fig.11 As shown, the first groove 34a and the second groove 34b can be arranged relative to each other. For example, the first groove 34a and the second groove 34b can be arranged directly opposite to each other. Of course, directly opposite to each other does not only mean completely directly opposite to each other, but also can have a certain error. The error range varies depending on the process and equipment. As long as it is within the error range, it is considered to be relatively arranged.

[0108] In this case, the sum of the depth of the first groove 34a and the depth of the second groove 34b is less than or equal to 50% of the thickness of the reinforcement layer 3. For example, the sum of the depth of the first groove 34a and the depth of the second groove 34b can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% and so on of the thickness of the reinforcement layer 3.

[0109] If the sum of the depth of the first groove 34a and the depth of the second groove 34b is too large, the impact resistance of the reinforcing layer 3 is lost; therefore, the above numerical range enables the reinforcing layer 3 to have both flexibility and impact resistance.

[0110] In this example embodiment, in the second direction Y, the ratio of the length of the reinforcement layer 3 to the length of the recessed structure 11 is greater than or equal to 0.75 and less than or equal to 1. For example, the ratio of the length of the reinforcement layer 3 to the length of the recessed structure 11 can be 0.78, 0.8, 0.82, 0.85, 0.87, 0.9, 0.93, 0.95, 0.98, etc.

[0111] Moreover, in the first direction X, the ratio of the width of the reinforcing layer 3 to the width of the recessed structure 11 is greater than or equal to 0.75 and less than or equal to 1. For example, the ratio of the width of the reinforcing layer 3 to the width of the recessed structure 11 may be 0.78, 0.8, 0.82, 0.85, 0.87, 0.9, 0.93, 0.95, 0.98, etc. The first direction X intersects the second direction Y. For example, the first direction X may be perpendicular to the second direction Y.

[0112] The length and width of the reinforcing layer 3 may be the same as the length and width of the recessed structure 11 , or may be slightly smaller than the length and width of the recessed structure 11 .

[0113] If the ratio of the length of the reinforcing layer 3 to the length of the recessed structure 11 and the ratio of the width of the reinforcing layer 3 to the width of the recessed structure 11 are too small, it is not conducive to the full area protection of the reinforcing layer 3. The above numerical range enables the reinforcing layer 3 to achieve full protection.

[0114] In addition, according to the processing accuracy of the actual process, the dimensions of the reinforcement layer 3 and the recessed structure 11 are allowed to have a tolerance of ±500 μm.

[0115] Reference Figure 3 As shown, when the length and width of the reinforcing layer 3 are slightly smaller than those of the recessed structure 11 , the flexible layer 2 fills the gap between the reinforcing layer 3 and the side wall of the recessed structure 11 , that is, the flexible layer 2 wraps the reinforcing layer 3 .

[0116] In some example embodiments of the present disclosure, reference is made to Figure 3 and Figures 5 to 7 As shown, the reinforcing layer 3 may include a first portion 31, a second portion 32 and a third portion 33 sequentially connected along the first direction X. In the thickness direction Z, the thickness of the first portion 31 is greater than the thickness of the second portion 32, and the thickness of the third portion 33 is greater than the thickness of the second portion 32, that is, in the first direction X, the thickness of the middle portion of the reinforcing layer 3 is less than the thickness of the two end portions. The thickness of the first portion 31 and the thickness of the third portion 33 may be the same or different.

[0117] Since the curvature radius of the second part 32 of the reinforcing layer 3 after bending is smaller and the stress is larger, setting the thickness of the second part 32 of the reinforcing layer 3 to be thinner can reduce the stress after bending; and setting the thickness of the first part 31 and the third part 33 of the reinforcing layer 3 to be thicker can ensure the strength and impact resistance of the reinforcing layer 3.

[0118] In the first direction X, the width of the first portion 31 is less than or equal to 50% of the width of the second portion 32. For example, the width of the first portion 31 may be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or the like of the width of the second portion 32. The width of the third portion 33 is less than or equal to 50% of the width of the second portion 32. For example, the width of the third portion 33 may be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or the like of the width of the second portion 32.

[0119] If the width of the first part 31 and the width of the third part 33 are set too wide, making the width of the second part 32 too narrow, the stress of the second part 32 will be too concentrated after the reinforcing layer 3 is bent, resulting in the loss of the bending performance of the reinforcing layer 3, which may easily cause cracks or breakage in the second part 32.

[0120] Reference Figure 3 and Figure 4 As shown, the approximate positions of the first connection part 112-3 and the second connection part 113-4 are indicated by circular dotted lines in the figure, and the relative relationship between the first connection part 112-3 and the first part 31, and the relative relationship between the second connection part 113-4 and the third part 33 are indicated by straight dotted lines in the figure; the bottom wall 113 is connected to the first transition surface 112 to form the first connection part 112-3. The first connection part 112-3 may include a portion of the bottom wall 113 close to the first transition surface 112 and a portion of the first transition surface 112 close to the bottom wall 113. After the flexible cover plate 10 is bent, the stress at the first connection part 112-3 is relatively concentrated, and the thickness at the first connection part 112-3 is relatively thin, so that cracks or even fractures are easily generated at the first connection part 112-3.

[0121] The first connection part 112-3 is arranged opposite to the first part 31; since the first part 31 is thicker and stronger, a part of the bending stress can be borne by the first part 31, so that the stress at the first connection part 112-3 is smaller, and it is not easy to generate cracks or breakage at the first connection part 112-3.

[0122] The bottom wall 113 is connected to the second transition surface 114 to form a second connection portion 113-4, and the second connection portion 113-4 may include a portion of the bottom wall 113 close to the second transition surface 114 and a portion of the second transition surface 114 close to the bottom wall 113. After the flexible cover 10 is bent, the stress at the second connection portion 113-4 is relatively concentrated, and the thickness at the second connection portion 113-4 is relatively thin, so that cracks or even fractures are easily generated at the second connection portion 113-4.

[0123] The second connection part 113-4 is arranged opposite to the third part 33; since the third part 33 is thicker and stronger, a part of the bending stress can be borne by the third part 33, so that the stress at the second connection part 113-4 is smaller, and it is not easy to produce cracks or breakage at the second connection part 113-4.

[0124] Reference Figure 5-Figure 7 As shown, the first part 31 and the third part 33 can be set as a cylinder, a cuboid, a rounded cuboid, etc., so that the shape of the cross section of the first part 31 and the third part 33 perpendicular to the second direction Y can be a circle, a rectangle, a rounded rectangle, etc. The second part 32 is set as a cuboid film layer, so that the shape of the cross section of the second part 32 perpendicular to the second direction Y can be a rectangle. Of course, the first part 31 and the third part 33 can also be other shapes, which are not described here one by one.

[0125] In addition, in this case, a groove 34 may also be set on the reinforcing layer 3, and the ratio of the depth of the groove 34 to the thickness of the reinforcing layer 3 may be within the range described above, wherein the thickness of the reinforcing layer 3 refers to the thickness of the reinforcing layer 3 at the position where the groove 34 is set.

[0126] Reference Figure 2 , Figure 3 , Figure 8 , Fig.14 and Fig.15 As shown, in some exemplary embodiments of the present disclosure, the ultra-thin glass layer 1 of unequal thickness has two surfaces arranged opposite to each other. A recessed structure 11 may be arranged on only one of the surfaces. The flexible layer 2 and the reinforcing layer 3 are arranged in the recessed structure 11.

[0127] Reference Figure 16-Figure 19 As shown, in some other example embodiments of the present disclosure, recessed structures 11 may be provided on both surfaces, and the recessed structures 11 on the two surfaces may be arranged relatively to each other. For example, the recessed structures 11 on the two surfaces may be arranged directly opposite to each other. Of course, directly opposite to each other does not only mean completely directly opposite to each other, but may also have a certain error. The error range may vary depending on the process and the equipment. As long as it is within the error range, it is considered to be relatively arranged.

[0128] Reference Fig.16 As shown, the recessed structures 11 on both surfaces are provided with a flexible layer 2 and a reinforcing layer 3. The flexible layer 2 and the reinforcing layer 3 in the recessed structures 11 on both surfaces may be symmetrically arranged or asymmetrically arranged.

[0129] Reference Figure 17-Figure 19 As shown, the two relatively arranged surfaces of the ultra-thin glass layer 1 of unequal thickness are the first surface 1a and the second surface 1b, the recessed structure 11 arranged on the first surface 1a is the first recessed structure 11a, and the recessed structure 11 arranged on the second surface 1b is the second recessed structure 11b, and only the flexible layer 2 is arranged in the first recessed structure 11a, and the flexible layer 2 and the strengthening layer 3 are arranged in the second recessed structure 11b.

[0130] The specific structures of the flexible layer 2 and the reinforcing layer 3 have been described in detail above, so they will not be repeated here.

[0131] The number of layers and positional relationship of the flexible layer 2 and the reinforcing layer 3 in a recessed structure are described below. It should be noted that when the flexible layer 2 and the reinforcing layer 3 are provided in the recessed structures 11 on both surfaces, the following exemplary implementations can be combined arbitrarily.

[0132] Reference Fig.19As shown, in a recessed structure 11, the flexible layer 2 is set as a layer, and the reinforcing layer 3 is set as a layer. The reinforcing layer 3 is located on the side of the flexible layer 2 away from the ultra-thin glass layer 1 of unequal thickness, that is, the flexible layer 2 is located on the inner side, and the reinforcing layer 3 is located on the outer side. The reinforcing layer 3 can protect the flexible layer 2.

[0133] Reference Fig.14 and Fig.15 As shown, in a recessed structure 11, the strengthening layer 3 is provided as two layers, the flexible layer 2 is provided as one layer, and at least one strengthening layer 3 is located on the side of the flexible layer 2 away from the ultra-thin glass layer 1 of unequal thickness. Fig.15 As shown, the flexible layer 2 may be located between two reinforcing layers 3, so that one reinforcing layer 3 is located on the side of the flexible layer 2 away from the ultra-thin glass layer 1 of unequal thickness, and one reinforcing layer 3 is located on the side of the flexible layer 2 close to the ultra-thin glass layer 1 of unequal thickness; Fig.14 As shown, the two reinforcing layers 3 may be both located on the side of the flexible layer 2 away from the unequal thickness ultra-thin glass layer 1. The moduli of the two reinforcing layers 3 may be the same or different.

[0134] Reference Figure 16-18 As shown, in a concave structure 11, the flexible layer 2 is provided as at least two layers, the reinforcing layer 3 is provided as at least one layer, and the reinforcing layer 3 and the flexible layer 2 are provided alternately. Fig.16 and Fig.17 As shown, in a concave structure 11, the flexible layer 2 is provided as two layers, the reinforcing layer 3 is provided as one layer, and the reinforcing layer 3 is provided between the two flexible layers 2, so that the reinforcing layer 3 and the flexible layer 2 are provided alternately, and the modulus of the two flexible layers 2 can be the same or different. Fig.18 As shown, in a recessed structure 11 , the flexible layer 2 is configured as three layers, and the reinforcing layer 3 is configured as two layers. Each reinforcing layer 3 is disposed between two flexible layers 2 , so that the reinforcing layers 3 and the flexible layers 2 are alternately disposed.

[0135] In a recessed structure 11 , the sum of the thickness of all the flexible layers 2 and the thickness of all the reinforcing layers 3 may be less than or equal to the depth of the recessed structure 11 .

[0136] In other exemplary embodiments, the outermost flexible layer 2 extends outside the recessed structure 11. For example, the outermost flexible layer 2 may protrude from the ultra-thin glass layers 1 of different thicknesses. That is, in one recessed structure 11, the sum of the thickness of all the flexible layers 2 and the thickness of all the reinforcing layers 3 may be greater than the depth of the recessed structure 11. Fig.18 As shown, the flexible layer 2 located at the outermost layer may also cover the surface of the ultra-thin glass layer 1 of unequal thickness in the non-bending area FZW, which can improve the connection strength between the flexible layer 2 and the reinforcing layer 3 filled in the recessed structure 11 and the recessed structure 11, and prevent the flexible layer 2 and the reinforcing layer 3 from escaping from the recessed structure 11.

[0137] Of course, in some other exemplary embodiments of the present disclosure, the outermost reinforcement layer 3 may extend outside the recessed structure 11. For example, the outermost reinforcement layer 3 may protrude from the ultra-thin glass layer 1 of unequal thickness, that is, in a recessed structure 11, the sum of the thickness of all the flexible layers 2 and the thickness of all the reinforcement layers 3 may be greater than the depth of the recessed structure 11. The outermost reinforcement layer 3 may cover the surface of the ultra-thin glass layer 1 of unequal thickness in the non-bending area FZW, which can also improve the connection strength between the flexible layer 2 and the reinforcement layer 3 filled in the recessed structure 11 and the recessed structure 11, and prevent the flexible layer 2 and the reinforcement layer 3 from escaping from the recessed structure 11; moreover, the impact resistance of the ultra-thin glass layer 1 of unequal thickness in the non-bending area FZW can be improved.

[0138] Based on the same inventive concept, the exemplary embodiment of the present disclosure provides a flexible display panel, referring to Fig. 20 As shown, the flexible display panel may include a display substrate 20 and a flexible cover plate 10; the flexible cover plate 10 is any one of the flexible cover plates 10 described above, and the flexible cover plate 10 is arranged on the light-emitting side of the display substrate 20. The specific structure of the flexible cover plate 10 has been described in detail above, so it will not be repeated here.

[0139] The display substrate 20 can be an OLED (Organic Electroluminescence Display) display substrate, a QLED (Quantum Dot Light Emitting Diodes) display substrate, a Micro-LED (Micro-light emitting diode) display substrate, etc.; the display substrate 20 has a light emitting side and a non-light emitting side, the light emitting side and the non-light emitting side are arranged opposite to each other, and a picture can be displayed on the light emitting side, and the side that displays the picture is the display surface.

[0140] The display substrate 20 may include a base substrate 201, a driving backplane 202 and a light emitting device 203, wherein the driving backplane 202 may drive the light emitting device 203 to emit light. The driving backplane 202 is disposed on one side of the base substrate 201, and the light emitting device 203 is disposed on the side of the driving backplane 202 away from the base substrate 201; a touch substrate 30 may be disposed on the light emitting side of the display substrate 20, that is, the touch substrate 30 is disposed on the side of the light emitting device 203 away from the base substrate 201; a flexible cover plate 10 may be disposed on the side of the touch substrate 30 away from the display substrate 20, so that the flexible cover plate 10 is disposed on the light emitting side of the display substrate 20.

[0141] Based on the same inventive concept, an exemplary embodiment of the present disclosure provides a foldable display device, which may include the flexible display panel described above.

[0142] The specific type of the foldable display device is not particularly limited. Any type of foldable display device commonly used in the art can be used, such as mobile devices such as mobile phones, wearable devices such as watches, VR devices, etc. Those skilled in the art can make corresponding choices based on the specific purpose of the foldable display device, which will not be repeated here.

[0143] It should be noted that, in addition to the flexible display panel, the foldable display device also includes other necessary components and components, such as the display for example, such as the outer casing, circuit board, power cord, etc. Those skilled in the art can make corresponding supplements according to the specific use requirements of the display device, which will not be repeated here.

[0144] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification 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 flexible cover having a bending area and a non-bending area arranged along a first direction, characterized in that: The flexible cover plate comprises: Ultra-thin glass layers of unequal thickness, wherein a concave structure is provided on the ultra-thin glass layers of unequal thickness, and at least a portion of the concave structure is located in the bending area; A flexible layer, at least disposed in the recessed structure; The reinforcing layer is at least arranged in the recessed structure, the modulus of the reinforcing layer is greater than the modulus of the flexible layer, and the modulus of the reinforcing layer is less than the modulus of the ultra-thin glass layers of unequal thickness.

2. The flexible cover according to claim 1, characterized in that: The reinforcement layer is provided with a groove, and the groove extends along a second direction, and the second direction is perpendicular to the first direction.

3. The flexible cover according to claim 2, characterized in that: The groove is arranged on a side of the reinforcing layer close to the bottom wall of the recessed structure, or the groove is arranged on a side of the reinforcing layer away from the bottom wall of the recessed structure.

4. The flexible cover according to claim 3, characterized in that: The depth of the groove is less than or equal to 50% of the thickness of the reinforcement layer.

5. The flexible cover according to claim 2, characterized in that: The groove arranged on the side of the reinforcing layer close to the bottom wall of the recessed structure is a first groove, and the groove arranged on the side of the reinforcing layer away from the bottom wall of the recessed structure is a second groove. The first groove and the second groove are staggered, or the first groove and the second groove are opposite to each other.

6. The flexible cover according to claim 5, characterized in that: The sum of the depth of the first groove and the depth of the second groove is less than or equal to 50% of the thickness of the reinforcement layer.

7. The flexible cover according to any one of claims 1 to 6, characterized in that: The ratio of the absolute value of the difference between the refractive index of the flexible layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.5%, and the ratio of the absolute value of the difference between the refractive index of the strengthening layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.5%.

8. The flexible cover according to any one of claims 1 to 6, characterized in that: The ratio of the absolute value of the difference between the refractive index of the flexible layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.3%, and the ratio of the absolute value of the difference between the refractive index of the strengthening layer and the refractive index of the ultra-thin glass layer of unequal thickness to the refractive index of the ultra-thin glass layer of unequal thickness is less than or equal to 0.3%.

9. The flexible cover according to any one of claims 1 to 6, characterized in that: The modulus of the reinforcement layer is greater than or equal to 0.1 GPa and less than or equal to 6 GPa, and the modulus of the flexible layer is greater than or equal to 0.01 GPa and less than or equal to 1 GPa.

10. The flexible cover according to any one of claims 1 to 6, characterized in that: The ratio of the total thickness of the reinforcement layer to the depth of the recessed structure is greater than or equal to 0.2 and less than or equal to 0.

7.

11. The flexible cover according to any one of claims 1 to 6, characterized in that: The ratio of the total thickness of the reinforcement layer to the depth of the recessed structure is greater than or equal to 0.3 and less than or equal to 0.

5.

12. The flexible cover according to any one of claims 1 to 6, characterized in that: In the second direction, the ratio of the length of the reinforcing layer to the length of the recessed structure is greater than or equal to 0.75 and less than or equal to 1; in the first direction, the ratio of the width of the reinforcing layer to the width of the recessed structure is greater than or equal to 0.75 and less than or equal to 1, and the first direction intersects with the second direction.

13. The flexible cover according to any one of claims 1 to 6, characterized in that: The reinforcement layer includes a first portion, a second portion, and a third portion sequentially connected along the first direction, the thickness of the first portion is greater than the thickness of the second portion, and the thickness of the third portion is greater than the thickness of the second portion.

14. The flexible cover according to claim 13, characterized in that: In the first direction, a width of the first portion is less than or equal to 50% of a width of the second portion, and a width of the third portion is less than or equal to 50% of a width of the second portion.

15. The flexible cover according to claim 13, characterized in that: The recessed structure includes a first side wall, a first transition surface, a bottom wall, a second transition surface and a second side wall connected in sequence; the bottom wall is connected to the first transition surface to form a first connecting portion, and the first connecting portion is arranged opposite to the first portion; the bottom wall is connected to the second transition surface to form a second connecting portion, and the second connecting portion is arranged opposite to the third portion.

16. The flexible cover according to any one of claims 1, characterized in that: The ultra-thin glass layer of unequal thickness has two surfaces arranged opposite to each other; the two surfaces are both provided with the recessed structure, and the recessed structures of the two surfaces are arranged opposite to each other, or the recessed structure is only provided on one of the surfaces.

17. The flexible cover according to claim 16, characterized in that: The flexible layer and the reinforcing layer are arranged in the recessed structures on the two surfaces; Alternatively, the two relatively arranged surfaces of the ultra-thin glass layers of unequal thickness are the first surface and the second surface, the recessed structure arranged on the first surface is the first recessed structure, the recessed structure arranged on the second surface is the second recessed structure, only the flexible layer is arranged in the first recessed structure, and the flexible layer and the reinforcing layer are arranged in the second recessed structure.

18. The flexible cover according to claim 16 or 17, characterized in that: In one of the recessed structures, the flexible layer is provided as at least two layers, the reinforcing layer is provided as at least one layer, and the reinforcing layer and the flexible layer are alternately provided.

19. The flexible cover according to claim 18, characterized in that: The outermost flexible layer extends outside the concave structure.

20. The flexible cover according to claim 16 or 17, characterized in that: In one of the recessed structures, the reinforcement layer is provided as two layers, the flexible layer is provided as one layer, and at least one reinforcement layer is located on a side of the flexible layer away from the ultra-thin glass layers of unequal thickness.

21. The flexible cover according to claim 16 or 17, characterized in that: In one of the recessed structures, the flexible layer is provided as one layer, the reinforcing layer is provided as one layer, and the reinforcing layer is located on a side of the flexible layer away from the ultra-thin glass layers of unequal thickness.

22. A flexible display panel, characterized in that: include: Display substrate; The flexible cover plate is the flexible cover plate according to any one of claims 1 to 21, and the flexible cover plate is arranged on the light output side of the display substrate.

23. A foldable display device, characterized in that: Includes the flexible display panel as described in claim 22.

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