Flexible display module, manufacturing method therefor, adhesive and flexible display apparatus

Abstract

A flexible display module, a manufacturing method therefor, an adhesive and a flexible display apparatus. The flexible display module (10) comprises a flexible display panel (1) and an adhesive layer group (2); the flexible display panel (1) has a non-edge area (11) and an edge area (12) surrounding the non-edge area (11); the adhesive layer group (2) is arranged on a display side of the flexible display panel (1), and the adhesive layer group (2) comprises a first portion (21) and a second portion (22), the first portion (21) being at least arranged in the non-edge area(11), and the second portion (22) being arranged in the edge area(12); the adhesive layer group (2) comprises an adhesive, the adhesive comprising a photo-degradable cross-linking agent and / or a thermo-degradable cross-linking agent; the second portion (22) is configured such that under the action of light and / or heat, the storage modulus of the second portion (22) is less than the storage modulus of the first portion (21) and / or the cross-linking density of the second portion (22) is less than the cross-linking density of the first portion (21).

Description

Flexible display modules and their manufacturing methods, adhesives and flexible display devices Technical Field

[0001] This disclosure relates to the field of display technology, and more specifically, to a flexible display module and its preparation method, an adhesive, and a flexible display device. Background Technology

[0002] Currently, flexible display devices are pursuing the ultimate in thinness and lightness, resulting in increasingly extreme bending shapes, that is, smaller and smaller bending radii, which makes the adhesive layer in the display module prone to problems such as bubbles and delamination.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a flexible display module, its preparation method, adhesive, and flexible display device.

[0005] According to one aspect of this disclosure, a flexible display module is provided, comprising:

[0006] A flexible display panel having a non-edge region and an edge region surrounding the non-edge region;

[0007] An adhesive layer assembly is disposed on the display side of the flexible display panel. The adhesive layer assembly includes a first portion and a second portion. The first portion is disposed at least in the non-edge region, and the second portion is disposed in the edge region. The adhesive layer assembly includes an adhesive, which includes a photodegradable crosslinking agent and / or a thermally degradable crosslinking agent. The second portion is configured such that, under the action of light and / or heat, the storage modulus of the second portion is less than the storage modulus of the first portion, and / or the crosslinking density of the second portion is less than the crosslinking density of the first portion.

[0008] In one exemplary embodiment of this disclosure, the energy storage modulus of the second portion is less than or equal to 20 kPa, the energy storage modulus of the first portion is greater than or equal to 40 kPa and less than or equal to 200 kPa, and / or the crosslinking density of the second portion is less than or equal to 0.05 mmol / cm^3, and the crosslinking density of the first portion is greater than or equal to 0.1 mmol / cm^3 and less than or equal to 1 mmol / cm^3.

[0009] In one exemplary embodiment of this disclosure, air bubbles are formed within the adhesive layer group in the edge region, the maximum size of the air bubbles being less than or equal to 50 μm.

[0010] In an exemplary embodiment of this disclosure, the flexible display panel is a foldable display panel, the edge region includes an edge bending region and an edge non-bending region, the second portion is disposed in the edge bending region, and the first portion is also disposed in the edge non-bending region;

[0011] Alternatively, the flexible display panel is a rollable display panel, and the edge region includes a rollable bending region and a rollable non-bending region, with the second part located in the rollable bending region and the first part also located in the rollable non-bending region.

[0012] In one exemplary embodiment of this disclosure, the adhesive layer group includes a first adhesive layer, and the flexible display module further includes:

[0013] The first cover plate layer is bonded to the side of the first adhesive layer opposite to the flexible display panel.

[0014] In one exemplary embodiment of this disclosure, the adhesive layer group includes a first adhesive layer and a second adhesive layer, and the flexible display module further includes:

[0015] A first cover plate layer is bonded to the side of the first adhesive layer opposite to the flexible display panel, and a second adhesive layer is bonded to the side of the first cover plate layer opposite to the flexible display panel.

[0016] The second cover layer is bonded to the side of the second adhesive layer opposite to the flexible display panel.

[0017] In one exemplary embodiment of this disclosure, the orthographic projection of the first cover layer on the flexible display panel is located within the orthographic projection of the adhesive layer group on the flexible display panel, and there is a non-zero gap between the edge line of the orthographic projection of the first cover layer on the flexible display panel and the edge line of the orthographic projection of the adhesive layer group on the flexible display panel, so that the portions of the first adhesive layer and the second adhesive layer protruding from the first cover layer are connected as one unit.

[0018] In one exemplary embodiment of this disclosure, the orthographic projection of the second portion on the flexible display panel overlaps with the orthographic projection of the first cover layer on the flexible display panel.

[0019] In an exemplary embodiment of this disclosure, the orthographic projection of the first cover layer on the flexible display panel is located within the orthographic projection of the second cover layer on the flexible display panel, and there is a non-zero gap between the edge line of the orthographic projection of the first cover layer on the flexible display panel and the edge line of the orthographic projection of the second cover layer on the flexible display panel.

[0020] In one exemplary embodiment of this disclosure, the photodegradable crosslinking agent includes one, two, or three of the following: a coumarin-based crosslinking agent, an azobenzene-based crosslinking agent, and an O-nitrophenyl-based crosslinking agent.

[0021] In one exemplary embodiment of this disclosure, the coumarin-based crosslinking agent includes one, two, or more of the following: coumarin-6-based crosslinking agent, coumarin diacrylate, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymer, and photofragmentable coumarin derivative.

[0022] In one exemplary embodiment of this disclosure, the azobenzene-based crosslinking agent includes one, two, or more of azobenzene diacrylate, azobenzene-containing polyethylene glycol, azobenzene-based dendritic polymer, azobenzene derivatives containing azido groups, and azobenzene-terminated polyesters.

[0023] In one exemplary embodiment of this disclosure, the O-nitrophenyl-based crosslinking agent includes one, two, or more of the following: O-nitrophenyl 1,6-hexanediamine, O-nitrophenyl methacrylate, O-nitrophenyl-modified polyvinyl alcohol, polymers of O-nitrophenyl derivatives, and dendritic polymers based on O-nitrophenyl.

[0024] In one exemplary embodiment of this disclosure, the thermally degradable crosslinking agent includes melamine, bifunctional polyether, bifunctional polyester, and one, two, or more compounds containing amino, hydroxyl, or carboxylic acid functional groups.

[0025] In one exemplary embodiment of this disclosure, the bifunctional polyether comprises a dihydroxy polyether.

[0026] In one exemplary embodiment of this disclosure, the compound containing amino, hydroxyl, or carboxylic acid functional groups includes one, two, or more of diethylenetriamine, butanetetracarboxylic acid, maleic anhydride, succinic anhydride, 2,4-diisocyanate, and 2,6-diisocyanate.

[0027] In one exemplary embodiment of this disclosure, the photodegradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the thermally degradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the sum of the weight parts of the photodegradable crosslinking agent and the thermally degradable crosslinking agent is 0.01-2 parts by weight; the adhesive raw materials further include:

[0028] Acrylic ester monomer, 80-90 parts by weight;

[0029] Polar acrylic comonomer, in parts by weight of 2-15;

[0030] Free radical initiator, in parts by weight of 0.01-2 parts;

[0031] A thermal crosslinking agent and / or a photocrosslinking agent, wherein the thermal crosslinking agent is present in a weight ratio of 0.01-5 parts; or the photocrosslinking agent is present in a weight ratio of 0.01-5 parts; or the sum of the weight ratios of the thermal crosslinking agent and the photocrosslinking agent is 0.01-5 parts.

[0032] In one exemplary embodiment of this disclosure, the acrylate monomer includes one, two, or more of linear monofunctional acrylates, branched monofunctional acrylates, and methacrylates.

[0033] In one exemplary embodiment of this disclosure, the polar acrylic comonomer includes one, two, or more of acrylic acid, methacrylic acid, and methacrylamide.

[0034] In one exemplary embodiment of this disclosure, the free radical initiator includes a thermal initiator and / or a photoinitiator.

[0035] In one exemplary embodiment of this disclosure, the thermal initiator includes a peroxide or an azo compound.

[0036] In one exemplary embodiment of this disclosure, the thermal crosslinking agent includes one, two, or more of the following: a polyfunctional isocyanate, a polyfunctional aziridine, and an epoxy compound.

[0037] In one exemplary embodiment of this disclosure, the photocrosslinking agent includes a non-copolymerized photocrosslinking agent and / or a copolymerized photocrosslinking agent.

[0038] In one exemplary embodiment of this disclosure, the adhesive raw materials further include:

[0039] Plasticizer, 5-10 parts by weight;

[0040] And / or, 3-5 parts by weight of elastomer monomer;

[0041] And / or, a molecular weight control agent, in parts by weight of 0.01-1;

[0042] And / or, coupling agent, in parts by weight of 0.1-3 parts.

[0043] According to another aspect of this disclosure, an adhesive is provided, the raw materials of which include:

[0044] Acrylic ester monomer, 80-90 parts by weight;

[0045] Polar acrylic comonomer, in parts by weight of 2-15;

[0046] Free radical initiator, in parts by weight of 0.01-2 parts;

[0047] A thermal crosslinking agent and / or a photocrosslinking agent, wherein the thermal crosslinking agent is present in a weight ratio of 0.01-5 parts; or the photocrosslinking agent is present in a weight ratio of 0.01-5 parts; or the sum of the weight ratios of the thermal crosslinking agent and the photocrosslinking agent is 0.01-5 parts.

[0048] The crosslinking agent is photodegradable and / or thermally degradable, wherein the photodegradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the thermally degradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the combined amount of the photodegradable crosslinking agent and the thermally degradable crosslinking agent is 0.01-2 parts by weight.

[0049] According to another aspect of this disclosure, a method for fabricating a flexible display module is provided, comprising:

[0050] A flexible display panel is provided, the flexible display panel having a non-edge region and an edge region surrounding the non-edge region;

[0051] An adhesive material layer group is formed on the display side of the flexible display panel, and at least a portion of the adhesive material layer group located in the edge region is irradiated and / or heated to form a second part, while the adhesive material layer group that is not irradiated and heated forms a first part. The first part is located at least in the non-edge region, and the second part is located in the edge region. The storage modulus of the second part is less than that of the first part, and / or the crosslinking density of the second part is less than that of the first part.

[0052] According to another aspect of this disclosure, a flexible display device is provided, comprising: the flexible display module described in any one of the preceding claims.

[0053] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0054] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0055] Figure 1 is a top view of an example embodiment of the flexible display module of this disclosure.

[0056] Figure 2 is a top view of another example embodiment of the flexible display module of this disclosure.

[0057] Figure 3 is a schematic diagram of the adhesive layer between the flexible display panel and the first cover plate layer subjected to bending and compressive forces.

[0058] Figure 4 is a schematic diagram of the adhesive layer assembly between the flexible display panel and the first cover plate layer subjected to bending tensile force.

[0059] Figure 5 is a schematic diagram of the microstructure of bubble expansion in the adhesive layer group in Figure 4.

[0060] Figure 6 is a structural schematic diagram of an example embodiment of preventing crack propagation in the related art.

[0061] Figure 7 is a schematic diagram of an example embodiment of preventing crack propagation in the related art.

[0062] Figure 8 is a cross-sectional view of an example embodiment of the flexible display module of this disclosure.

[0063] Figure 9 is a cross-sectional view of another example embodiment of the flexible display module disclosed herein.

[0064] Figure 10 is a flowchart illustrating an example embodiment of the fabrication method of the flexible display module disclosed herein.

[0065] Figure 11 is a schematic diagram of the structure at the bend of the foldable flexible display device.

[0066] Explanation of reference numerals in the attached drawings: 10. Flexible display module; 1. Flexible display panel; 11. Non-edge area; 12. Edge area; 121. Edge bending area; 122. Edge non-bending area; 123. Sliding bending area; 124. Sliding non-bending area; 2. Adhesive layer group; 2a. First adhesive layer; 2b. Second adhesive layer; 21. First part; 22. Second part; 31. First cover plate layer; 32. Second cover plate layer; 4. Bubble; 5. Middle frame; 6. Adhesive; 7. Wing plate; 81. Toughening structure; 82. Bridging structure; AA. Display area; NAA. Non-display area; X. First direction; Y. Second direction. Detailed Implementation

[0067] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0068] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0069] The terms “a,” “one,” “the,” “the,” 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 indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markers and are not a limitation on the number of objects.

[0070] In this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0071] This disclosure provides an example embodiment of a flexible display module. Referring to Figures 1, 2, 8, and 9, the flexible display module may include a flexible display panel 1 and an adhesive layer group 2. The flexible display panel 1 has a non-edge region 11 and an edge region 12 surrounding the non-edge region 11. The adhesive layer group 2 is disposed on the display side of the flexible display panel 1. The adhesive layer group 2 may include a first portion 21 and a second portion 22. The first portion 21 is at least disposed in the non-edge region 11, and the second portion 22 is disposed in the edge region 12. The adhesive layer group 2 may include an adhesive, which may include a photodegradable crosslinking agent and / or a thermally degradable crosslinking agent. The second portion 22 is configured such that, under the action of light and / or heat, the storage modulus of the second portion 22 is less than the storage modulus of the first portion 21, and / or the crosslinking density of the second portion 22 is less than the crosslinking density of the first portion 21.

[0072] In the display module disclosed herein, the energy storage modulus of the second part 22 is less than that of the first part 21, and / or the crosslinking density of the second part 22 is less than that of the first part 21; this makes the second part 22 more prone to deformation. During the bending or rolling process of the flexible display module, the second part 22 is less likely to develop cracks. Even if some cracks are generated after multiple bending or rolling, the second part 22 will resist the propagation of cracks, avoid the generation of large bubbles 4, and thus avoid delamination, and prevent bubbles 4 from expanding into the display area AA, so as to ensure the display effect of the display area AA.

[0073] In this example embodiment, the flexible display panel 1 can be an OLED (Organic Electroluminescence Display) display panel, or a QLED (Quantum Dot Light Emitting Diodes) display panel, a micro-LED (micro-Light Emitting Diode) display panel, a mini-LED (mini-Light Emitting Diode) display panel, etc.

[0074] The following explanation uses flexible display panel 1 as an example of an OLED display panel.

[0075] The flexible display panel 1 may include a flexible substrate, a driving substrate, and a light-emitting substrate. The driving substrate is disposed on one side of the substrate, and the light-emitting substrate is disposed on the side of the driving substrate opposite to the substrate. The driving substrate may include multiple driving circuits arranged in an array, and the light-emitting substrate may include multiple light-emitting devices arranged in an array. The driving circuits can drive the light-emitting devices to emit light.

[0076] Flexible display panels typically employ flexible substrates to enable bending and rolling. These flexible substrates are generally organic materials, such as polyimide (PI), polycarbonate, polyacrylate, polyetherimide, polyethersulfone, polyethylene terephthalate, and polyethylene naphthalate, among other resin-based materials. Flexible substrates can be formed from multiple layers of material; for example, they may include multiple substrate layers, the material of which can be any of the aforementioned materials. Alternatively, flexible substrates can also be single-layered, and can be any of the aforementioned materials.

[0077] The flexible display panel 1 may further include an encapsulation layer assembly disposed on the side of the light-emitting substrate facing away from the flexible substrate. For example, the encapsulation layer assembly may include a first inorganic layer, an organic layer, and a second inorganic layer; the first inorganic layer is disposed on the side of the light-emitting substrate facing away from the substrate; the material of the first inorganic layer may be silicon nitride (SiNx) or silicon oxynitride (SiNO), etc. The organic layer is disposed on the side of the first inorganic layer facing away from the flexible substrate, and the material of the organic layer may be acrylic, epoxide, or other organic materials. The second inorganic layer is disposed on the side of the organic layer facing away from the flexible substrate, and the material of the second inorganic layer may be silicon nitride (SiNx) or silicon oxynitride (SiNO), etc. The encapsulation layer assembly can encapsulate the light-emitting layer assembly, isolating it from corrosion by water / oxygen in the air.

[0078] In some exemplary embodiments of this disclosure, the flexible display panel 1 may further include a touch layer group disposed on the side of the encapsulation layer group facing away from the flexible substrate. The touch layer group enables the flexible display panel 1 to perform touch functions. The touch layer group may include a base layer, a first touch functional layer, a touch insulating layer, a second touch functional layer, and a protective layer stacked sequentially.

[0079] Referring to Figures 1 and 2, the flexible display panel 1 has a display area AA (Active Area) and a non-display area NAA. Specifically, the non-display area NAA may surround the outer periphery of the display area AA. The flexible display panel 1 may be rectangular, and the display area AA may be rectangular, such that the non-display area NAA is a rectangular frame.

[0080] In this example embodiment, Figures 1 and 2 are divided into a non-edge region 11 and an edge region 12 by dashed lines; the flexible display panel 1 has a non-edge region 11 and an edge region 12 surrounding the non-edge region 11; the flexible display panel 1 can be set as a rectangle, the non-edge region 11 can be set as a rectangle, and the edge region 12 is set as a rectangular frame.

[0081] The display area AA and the non-edge area 11 have only the outermost edge line. The display area AA can be located within the non-edge area 11. For example, the edge line of the display area AA can coincide with the edge line of the non-edge area 11, or there can be a non-zero gap between the edge line of the display area AA and the edge line of the non-edge area 11.

[0082] Both the edge region 12 and the non-display region NAA have an outer edge line and an inner edge line, and the outer edge line of the edge region 12 coincides with the outer edge line of the non-display region NAA.

[0083] The edge region 12 may be located within the non-display region NAA. For example, the inner edge of the edge region 12 may coincide with the inner edge of the non-display region NAA, or there may be a non-zero gap between the inner edge of the edge region 12 and the inner edge of the non-display region NAA.

[0084] An adhesive layer assembly 2 is disposed between the flexible display panel 1 and the first cover plate layer 31. Under external load, the adhesive layer assembly 2 undergoes whitening, fibrosis, or cavitation bubbles due to crack propagation. The macroscopic manifestation is the extension and expansion of bubbles. Specifically, as shown in Figure 3, during the bending or rolling process of the flexible display module, the adhesive layer assembly 2 may protrude outward from the edge of the flexible display panel 1 and the first cover plate layer 31 due to bending and compressive forces; as shown in Figures 4 and 5, the adhesive layer assembly 2 may be recessed inward into the flexible display panel 1 due to bending and tensile forces. The edges of the display panel 1 and the first cover layer 31; in Figure 5, the curves represent polymer chains, and the dashed lines represent cracks. When the polymer chains break, cracks are formed, and bubbles 4 will further extend to the display area AA as the cracks expand. As the number of bends or curls increases, the adhesive layer group 2 is subjected to cyclic tensile stress. Cracks will first appear in the adhesive layer group 2 in the edge area 12, and the cracks will further expand to form bubbles 4. As the number of bends or curls continues to increase, bubbles 4 will further extend to the display area AA, affecting the display effect.

[0085] Foldable and rollable display modules need to be able to withstand repeated folding, rolling, and unfolding. Under repeated bending of multi-layered structures, the shear slip capability of the adhesive layers becomes crucial. Any form of stress can lead to defects (delamination, buckling, cavitation bubbles in the adhesive, etc.).

[0086] Referring to Figure 6, a toughening structure 81 is provided in the adhesive layer group 2 to induce crack tip deflection, thereby generating fracture resistance and reducing the "driving force" at the crack tip. Referring to Figure 7, a bridging structure 82 is provided in the adhesive layer group 2 to generate fracture resistance and reduce the "driving force" at the crack tip. The toughening structure 81 and the bridging structure 82 can resist damage caused by crack tips; however, these structures inevitably have some defects, such as affecting the optical transparency of the adhesive layer group 2 or the reliability of folding fatigue bending.

[0087] In this exemplary embodiment, referring to Figures 8 and 9, an adhesive layer assembly 2 is provided on the display side of the flexible display panel 1. The adhesive layer assembly 2 may include a first portion 21 and a second portion 22, which are connected to each other. The first portion 21 is provided at least in the non-edge region 11. For example, the first portion 21 may be provided only in the non-edge region 11, as shown in Figures 1 and 2, or the first portion 21 may be provided not only in the non-edge region 11 but also in a part of the edge region 12. The second portion 22 is provided in the edge region 12. For example, the second portion 22 may be provided in the entire edge region 12, as shown in Figures 1 and 2, or the second portion 22 may be provided in a part of the edge region 12, and the first portion 21 may be provided in another part of the edge region 12.

[0088] The adhesive layer group 2 may include an adhesive, which may include a photodegradable crosslinking agent and / or a thermally degradable crosslinking agent. For example, the adhesive may include both a photodegradable crosslinking agent and a thermally degradable crosslinking agent, or it may include a photodegradable crosslinking agent or a thermally degradable crosslinking agent.

[0089] The second part 22 is configured such that, under the influence of light and / or heat, the energy storage modulus of the second part 22 is less than that of the first part 21, and / or, the crosslinking density of the second part 22 is less than that of the first part 21.

[0090] Specifically, when the adhesive includes a photodegradable crosslinking agent and a thermally degradable crosslinking agent, the second part 22 is configured such that, under the action of light and heat, the storage modulus of the second part 22 is less than the storage modulus of the first part 21, or the crosslinking density of the second part 22 is less than the crosslinking density of the first part 21; it can also be configured such that the storage modulus of the second part 22 is less than the storage modulus of the first part 21, and the crosslinking density of the second part 22 is less than the crosslinking density of the first part 21.

[0091] When the adhesive includes a photodegradable crosslinking agent, the second part 22 is configured such that, under the action of light, the storage modulus of the second part 22 is less than the storage modulus of the first part 21, or the crosslinking density of the second part 22 is less than the crosslinking density of the first part 21; it may also be configured such that the storage modulus of the second part 22 is less than the storage modulus of the first part 21, and the crosslinking density of the second part 22 is less than the crosslinking density of the first part 21.

[0092] When the adhesive includes a thermally degradable crosslinking agent, the second part 22 is configured such that, under the action of heat, the storage modulus of the second part 22 is less than the storage modulus of the first part 21, or the crosslinking density of the second part 22 is less than the crosslinking density of the first part 21; it may also be configured such that the storage modulus of the second part 22 is less than the storage modulus of the first part 21, and the crosslinking density of the second part 22 is less than the crosslinking density of the first part 21.

[0093] Storage modulus generally refers to Young's modulus. Young's modulus is a physical quantity that describes the resistance of a solid material to deformation. According to Hooke's Law, within the elastic limit of an object, stress and strain are directly proportional, and the ratio is called the Young's modulus of the material. It is a physical quantity characterizing the properties of a material and depends only on the material's inherent physical properties. The magnitude of Young's modulus indicates the stiffness of the material; the larger the Young's modulus, the less resistant it is to deformation.

[0094] The energy storage modulus of the second part 22 is smaller than that of the first part 21, making the second part 22 more prone to deformation. During the bending or rolling process of the flexible display module, the second part 22 is less likely to develop cracks. Even if some cracks are generated after multiple bending or rolling, the second part 22 will resist the expansion of cracks, avoid the generation of large bubbles 4, and prevent bubbles 4 from expanding into the display area AA, so as to ensure the display effect of the display area AA; and avoid the generation of delamination.

[0095] Crosslinking density refers to the number of crosslinks in a crosslinked polymer, typically expressed as the molecular weight of the crosslinked chain. A higher crosslinking density means more crosslinks per unit volume, indicating a greater degree of crosslinking. Crosslinking density significantly affects the physical properties of polymers. As crosslinking density increases, the polymer's modulus and hardness also increase.

[0096] The crosslinking density of the second part 22 is less than that of the first part 21, resulting in a lower modulus and hardness of the second part 22. This makes the second part 22 more prone to deformation. During the bending or rolling process of the flexible display module, the second part 22 is less likely to develop cracks. Even if some cracks are generated after multiple bending or rolling, the second part 22 will resist the propagation of cracks, avoid the generation of large air bubbles 4, and prevent air bubbles 4 from expanding into the display area AA, so as to ensure the display effect of the display area AA; and avoid delamination.

[0097] Furthermore, the adhesive layer group 2, which incorporates both photodegradable and thermally degradable crosslinking agents, still meets all optical transparency requirements, such as optical properties: haze less than or equal to 1%, and transmission hue b* less than or equal to 0.5.

[0098] Specifically, the energy storage modulus of the second part 22 is less than or equal to 20 kPa. For example, the energy storage modulus of the second part 22 can be 2 kPa, 5 kPa, 7 kPa, 10 kPa, 13 kPa, 15 kPa, 18 kPa, etc.

[0099] If the energy storage modulus of the second part 22 is too large, the second part 22 will not be able to achieve the above effect.

[0100] The energy storage modulus of the first part 21 is greater than or equal to 40 kPa and less than or equal to 200 kPa. For example, the energy storage modulus of the first part 21 can be 50 kPa, 70 kPa, 100 kPa, 130 kPa, 150 kPa, 180 kPa, etc.

[0101] If the energy storage modulus of the first part 21 is too small, the mechanical strength of the first part 21 will be insufficient. After the display module collides with a hard object, it will inevitably lead to display abnormalities, such as the generation of bright spots.

[0102] If the energy storage modulus of the first part 21 is too large, it will be easy for cracks to be generated during the bending or rolling process, which will affect the display effect.

[0103] The above-mentioned numerical range not only ensures that the mechanical strength of the first part 21 is sufficient to avoid display abnormalities caused by collisions between the display module and hard objects, but also ensures that the first part 21 is not prone to cracks during bending or rolling, thus avoiding affecting the display effect.

[0104] Specifically, the crosslinking density of the second part 22 is less than or equal to 0.05 mmol / cm^3. For example, the crosslinking density of the second part 22 can be 0.01 mmol / cm^3, 0.02 mmol / cm^3, 0.04 mmol / cm^3, etc.

[0105] The crosslinking density of the first part 21 is greater than or equal to 0.1 mmol / cm^3 and less than or equal to 1 mmol / cm^3. For example, the crosslinking density of the first part 21 can be 0.3 mmol / cm^3, 0.5 mmol / cm^3, 0.8 mmol / cm^3, etc.

[0106] In some exemplary embodiments of this disclosure, bubbles 4 may be formed within the adhesive layer group 2 of the edge region 12. The maximum size of the bubble 4 is less than or equal to 50 μm. For example, the maximum size of the bubble 4 may be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, etc.

[0107] In the prior art, the maximum size of bubble 4 can reach 1000μm, which is significantly smaller than the maximum size of bubble 4 in the prior art. Moreover, the second part 22 will block the expansion of bubble 4, so bubble 4 will not extend to the display area AA to ensure the display effect.

[0108] Referring to Figure 1, the flexible display panel 1 can be a foldable display panel. In this case, the edge region 12 can include an edge bending region 121 and an edge non-bending region 122. Two edge bending regions 121 can be provided, and they can be arranged opposite each other in a first direction X, which is perpendicular to the folding direction of the flexible display panel 1. Two edge non-bending regions 122 can also be provided, and they are connected to opposite sides of the two edge bending regions 121 in a second direction Y. The non-edge region 11 can include an inner bending region and an inner non-bending region. A second part 22 is provided in the edge bending region 121, but not in the edge non-bending region 122. A first part 21 is also provided in the edge non-bending region 122 of the edge region 12, that is, the first part 21 is provided in both the non-edge region 11 and the edge non-bending region 122.

[0109] Since the edge bending area 121 requires multiple bends, while the edge non-bending area 122 does not, the second part 22 is positioned in the edge bending area 121. This makes it less prone to cracking during the bending process of the flexible display module. Even if some cracks occur after multiple bends, the second part 22 will resist the propagation of the cracks, preventing the formation of large air bubbles 4 and preventing the air bubbles 4 from expanding into the display area AA, thus ensuring the display effect of the display area AA; and also preventing delamination.

[0110] Furthermore, the non-bent edge area 122 is more prone to collision with hard objects. The first part 21 is also provided in the non-bent edge area 122 of the edge area 12, which can ensure the mechanical strength of the non-bent edge area 122 and avoid display abnormalities caused by the collision between the non-bent edge area 122 and hard objects.

[0111] Referring to Figure 2, the flexible display panel 1 can be a rollable display panel. In this case, the edge region 12 can include a rollable bending region 123 and a rollable non-bending region 124. There can be two rollable bending regions 123, which can be two opposite regions of the edge region 12 in the first direction X. There can also be two rollable non-bending regions 124, which can be two opposite regions of the edge region 12 in the second direction Y. The rollable bending region 123, the rollable non-bending region 124, and the rollable bending region 123 are connected end to end to form the edge region 12.

[0112] The second part 22 is located in the sliding bending area 123, and the second part 22 is not located in the sliding non-bending area 124; the first part 21 is also located in the sliding non-bending area 124 of the edge area 12, that is, the first part 21 is located in the non-edge area 11 and the sliding non-bending area 124.

[0113] Since the sliding bending area 123 requires multiple bends, while the sliding non-bending area 124 does not, the second part 22 is positioned within the sliding bending area 123. This prevents the second part 22 from developing cracks during the bending process of the flexible display module. Even if some cracks do develop after multiple bends, the second part 22 will resist the propagation of the cracks, preventing the formation of large air bubbles 4 and preventing the air bubbles 4 from expanding into the display area AA, thus ensuring the display effect of the display area AA; and also preventing delamination.

[0114] Furthermore, the non-bending area 124 is more prone to collision with hard objects. The first part 21 is also provided in the non-bending area 124 of the edge area 12, which can ensure the mechanical strength of the non-bending area 124 and avoid display abnormalities caused by the collision of the non-bending area 124 with hard objects.

[0115] In some exemplary embodiments of this disclosure, referring to FIG8, the adhesive layer group 2 may include a first adhesive layer 2a, which is disposed on the display side of the flexible display panel 1. Specifically, the first adhesive layer 2a is disposed on the side of the touch layer group away from the flexible substrate. In this case, the flexible display module may further include a first cover layer 31, which is bonded to the side of the first adhesive layer 2a away from the flexible display panel 1. The first cover layer 31 may be ultra-thin glass (UTG).

[0116] In some exemplary embodiments of this disclosure, referring to FIG9, the adhesive layer group 2 may include a first adhesive layer 2a and a second adhesive layer 2b. The first adhesive layer 2a is disposed on the display side of the flexible display panel 1. Specifically, the first adhesive layer 2a is disposed on the side of the touch layer group away from the flexible substrate. In this case, the flexible display module may also include a first cover layer 31 and a second cover layer 32. The first cover layer 31 is bonded to the side of the first adhesive layer 2a away from the flexible display panel 1, and the second adhesive layer 2b is bonded to the side of the first cover layer 31 away from the flexible display panel 1. The second cover layer 32 is bonded to the side of the second adhesive layer 2b away from the flexible display panel 1.

[0117] The first cover layer 31 can be ultra-thin glass (UTG), and the second cover layer 32 can be PET (polyethylene terephthalate). The second cover layer 32 can protect the entire flexible display module.

[0118] The thickness of the first adhesive layer 2a is greater than or equal to 10 μm and less than or equal to 50 μm. For example, the thickness of the first adhesive layer 2a can be 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, etc.

[0119] The thickness of the second adhesive layer 2b is greater than or equal to 25 μm and less than or equal to 45 μm. For example, the thickness of the second adhesive layer 2b can be 28 μm, 30 μm, 32 μm, 35 μm, 37 μm, 40 μm, 43 μm, etc.

[0120] The thickness of the first cover plate layer 31 is greater than or equal to 20 and less than or equal to 40. For example, the thickness of the first cover plate layer 31 can be 23μm, 25μm, 28μm, 30μm, 32μm, 35μm, 37μm, etc.

[0121] The thickness of the second cover plate layer 32 is greater than or equal to 25 μm and less than or equal to 100 μm. For example, the thickness of the second cover plate layer 32 can be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, etc.

[0122] Optionally, the orthographic projection of the first cover layer 31 on the flexible display panel 1 lies within the orthographic projection of the second cover layer 32 on the flexible display panel 1, and there is a non-zero gap between the edge line of the orthographic projection of the first cover layer 31 on the flexible display panel 1 and the edge line of the orthographic projection of the second cover layer 32 on the flexible display panel 1. That is, the orthographic projection of the second cover layer 32 on the flexible display panel 1 covers and is larger than the orthographic projection of the first cover layer 31 on the flexible display panel 1, so that the second cover layer 32 can protect the entire flexible display module. This non-zero gap can be greater than 0 and less than or equal to 0.3 mm. For example, the non-zero gap can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.22 mm, 0.25 mm, 0.27 mm, etc.

[0123] The orthographic projection of the first cover layer 31 on the flexible display panel 1 lies within the orthographic projection of the adhesive layer assembly 2 on the flexible display panel 1, and there is a non-zero gap between the edge of the orthographic projection of the first cover layer 31 on the flexible display panel 1 and the edge of the orthographic projection of the adhesive layer assembly 2 on the flexible display panel 1. This non-zero gap can be greater than 0 and less than or equal to 0.3 mm. For example, the non-zero gap can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.22 mm, 0.25 mm, 0.27 mm, etc. That is, the orthographic projection of the adhesive layer group 2 on the flexible display panel 1 covers and is greater than the orthographic projection of the first cover layer 31 on the flexible display panel 1. In other words, the orthographic projection of the first adhesive layer 2a on the flexible display panel 1 covers and is greater than the orthographic projection of the first cover layer 31 on the flexible display panel 1, and the orthographic projection of the second adhesive layer 2b on the flexible display panel 1 covers and is greater than the orthographic projection of the first cover layer 31 on the flexible display panel 1. Thus, the portions of the first adhesive layer 2a and the second adhesive layer 2b protruding from the first cover layer 31 are connected as one unit. That is, the first adhesive layer 2a and the second adhesive layer 2b are connected as one unit at positions opposite to the periphery of the first cover layer 31, so that the first adhesive layer 2a and the second adhesive layer 2b completely cover the first cover layer 31 to protect the first cover layer 31.

[0124] Since the connection between the first adhesive layer 2a and the second adhesive layer 2b is essentially a structure where two layers of adhesive are stacked and bonded together, air bubbles 4 are more likely to form between the bonding surfaces of the first adhesive layer 2a and the second adhesive layer 2b. Therefore, the storage modulus of the second part 22 is less than that of the first part 21, and / or the crosslinking density of the second part 22 is less than that of the first part 21. This structure is more suitable for this structure and is more conducive to resisting the expansion of air bubbles 4, so as to ensure the display effect.

[0125] The edge line of the orthographic projection of the adhesive layer group 2 on the flexible display panel 1 can coincide with the edge line of the orthographic projection of the second cover layer 32 on the flexible display panel 1. The edge line of the flexible display panel 1 can coincide with the edge line of the adhesive layer group 2. The edge line of the flexible display panel 1 can coincide with the edge line of the second cover layer 32. That is, the edge lines of the adhesive layer group 2, the flexible display panel 1, and the second cover layer 32 can all coincide.

[0126] Of course, in other exemplary embodiments of this disclosure, two first cover layers 31 and two first adhesive layers 2a may also be provided, with the two first cover layers 31 and the two first adhesive layers 2a stacked alternately in sequence. A second adhesive layer 2b is adhered to the side of the upper first cover layer 31 facing away from the flexible display panel 1, and a second cover layer 32 is adhered to the side of the second adhesive layer 2b facing away from the flexible display panel 1. In this case, the portions of the two first adhesive layers 2a and the second adhesive layer 2b protruding from the first cover layer 31 are connected as one unit, that is, the two first adhesive layers 2a and the second adhesive layer 2b can be connected as one unit at positions opposite to the periphery of the first cover layer 31. The number of film layers and the stacking structure of the adhesive layer group 2 and the cover layer can also be other structures, which will not be described in detail here.

[0127] Referring to Figure 1, in the second direction Y, the edge line of the second portion 22 coincides at least with the edge line of the edge bending region 121. Of course, the edge line of the second portion 22 may also slightly extend beyond the edge line of the edge bending region 121. Referring to Figure 2, in the second direction Y, the edge line of the second portion 22 coincides with the edge line of the sliding bending region 123.

[0128] Referring to Figures 1, 2, 8 and 9, in the first direction X, the starting edge of the second part 22 can coincide with the edge line of the adhesive layer group 2, so that the starting edge of the second part 22 coincides with the edge line of the flexible display panel 1.

[0129] In some exemplary embodiments of this disclosure, the distance between the second portion 22 and the display area AA is greater than or equal to 0.1 mm and less than or equal to 0.3 mm. Specifically, the distance between the edge of the second portion 22 near the display area AA and the edge of the display area AA is greater than or equal to 0.1 mm and less than or equal to 0.3 mm. For example, the distance between the second portion 22 and the display area AA can be 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.25 mm, 0.27 mm, etc.

[0130] In some exemplary embodiments of this disclosure, the orthographic projection of the second portion 22 on the flexible display panel 1 overlaps with the orthographic projection of the first cover layer 31 on the flexible display panel 1, that is, the second portion 22 extends to the upper side and / or lower side of the first cover layer 31. Specifically, the width of the overlap between the second portion 22 and the first cover layer 31 is greater than or equal to 0.1 mm and less than or equal to 1 mm. For example, the width of the overlap between the second portion 22 and the first cover layer 31 can be 0.3 mm, 0.5 mm, 0.8 mm, etc.

[0131] In some exemplary embodiments of this disclosure, the photodegradable crosslinking agent may include, but is not limited to, one, two, or three of the following: coumarin-based crosslinking agents, azobenzene-based crosslinking agents, and O-nitrophenyl-based crosslinking agents. For example, the photodegradable crosslinking agent may include, but is not limited to, a coumarin-based crosslinking agent, azobenzene-based crosslinking agent, or O-nitrophenyl-based crosslinking agent; the photodegradable crosslinking agent may include, but is not limited to, a coumarin-based crosslinking agent and azobenzene-based crosslinking agent; the photodegradable crosslinking agent may include, but is not limited to, azobenzene-based crosslinking agent and O-nitrophenyl-based crosslinking agent; the photodegradable crosslinking agent may include, but is not limited to, a coumarin-based crosslinking agent, azobenzene-based crosslinking agent, and O-nitrophenyl-based crosslinking agent.

[0132] Specifically, coumarin-based crosslinking agents may include, but are not limited to, one, two, or more of the following: coumarin-6-based crosslinking agents, coumarin diacrylates, coumarin-functionalized polyvinyl alcohol (PVA), coumarin-based dendritic polymers, and photo-severable coumarin derivatives. For example, coumarin-based crosslinking agents may include, but are not limited to, coumarin-6-based crosslinking agents, coumarin diacrylates, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymers, or photo-severable coumarin derivatives; coumarin-based crosslinking agents may also include, but are not limited to, any two of the following: coumarin-6-based crosslinking agents, coumarin diacrylates, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymers, and photo-severable coumarin derivatives, which will not be listed individually here; coumarin-based crosslinking agents may also include, but are not limited to, coumarin-6-based crosslinking agents, coumarin diacrylates, and coumarin-functionalized... The coumarin-based crosslinking agent may be any three of the following: polyvinyl alcohol, coumarin-based dendritic polymers, and photo-severable coumarin derivatives, without further explanation. The coumarin-based crosslinking agent may also include, but is not limited to, any four of the following: coumarin-6-based crosslinking agent, coumarin diacrylate, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymers, and photo-severable coumarin derivatives, without further explanation.

[0133] Specifically, the crosslinking agent based on azobenzene can be, but is not limited to, one, two, or more of the following: azobenzene diacrylate, polyethylene glycol (PEG) containing azobenzene, azobenzene-based dendritic polymers, azobenzene derivatives containing azido groups, and azobenzene-terminated polyesters. That is, the crosslinking agent based on azobenzene can be, but is not limited to, any one of the following: azobenzene diacrylate, polyethylene glycol containing azobenzene, azobenzene-based dendritic polymers, azobenzene derivatives containing azido groups, and azobenzene-terminated polyesters; it can also be, but is not limited to, any two of these materials; it can also be, but is not limited to, any three or four of these materials; or it can include all of them. These will not be listed individually here.

[0134] Specifically, the crosslinking agent based on O-nitrophenyl can include, but is not limited to, one, two, or more of the following: O-nitrophenyl 1,6-hexanediamine, O-nitrophenyl methacrylate, O-nitrophenyl-modified polyvinyl alcohol (PVA), polymers of O-nitrophenyl derivatives (e.g., poly(N-isopropylacrylamide)), and dendritic polymers based on O-nitrophenyl. That is, the crosslinking agent based on O-nitrophenyl can include, but is not limited to, any one of the following: O-nitrophenyl 1,6-hexanediamine, O-nitrophenyl methacrylate, O-nitrophenyl-modified polyvinyl alcohol, polymers of O-nitrophenyl derivatives, and dendritic polymers based on O-nitrophenyl; it can also include, but is not limited to, any two of these materials; it can also include, but is not limited to, any three, four, or more of these materials; or it can include all of them. These will not be listed individually here.

[0135] In some exemplary embodiments of this disclosure, the thermally degradable crosslinking agent may include, but is not limited to, melamine, difunctional polyethers, difunctional polyesters, and one, two, or more compounds containing amino, hydroxyl, or carboxylic acid functional groups. That is, the thermally degradable crosslinking agent may include, but is not limited to, any one of melamine, difunctional polyethers, difunctional polyesters, and compounds containing amino, hydroxyl, or carboxylic acid functional groups, or may include, but is not limited to, any two, any three, or all of these materials; however, they will not be described individually here. Melamine is commonly used for crosslinking polyurethanes to form a network structure. Difunctional polyethers and difunctional polyesters can provide additional crosslinking points.

[0136] Specifically, the bifunctional polyether may include, but is not limited to, dihydroxy polyether. The bifunctional polyester may include, but is not limited to, polyethylene glycol diacrylate and hexanediol diacrylate.

[0137] Specifically, compounds containing amino, hydroxyl, or carboxylic acid functional groups may include, but are not limited to, one, two, or more of diethylenetriamine, butanetetracarboxylic acid, maleic anhydride, succinic anhydride, 2,4-diisocyanate, and 2,6-diisocyanate.

[0138] In some exemplary embodiments of this disclosure, when a photodegradable crosslinking agent is provided, the weight of the photodegradable crosslinking agent is 0.01-2 parts. For example, the weight of the photodegradable crosslinking agent can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.

[0139] When the weight of the photodegradable crosslinking agent is 0.01 parts, the second part 22 is configured such that, under the action of light, the storage modulus of the second part 22 is less than or equal to 5 kPa, and / or, the crosslinking density of the second part 22 is approximately 0.1 × 10⁻⁴ mol / cm³; when the weight of the photodegradable crosslinking agent is 1 part, the second part 22 is configured such that, under the action of light, the storage modulus of the second part 22 is approximately 15 kPa, and / or, the crosslinking density of the second part 22 is approximately 1 × 10⁻⁴ mol / cm³; when the weight of the photodegradable crosslinking agent is 2 parts, the second part 22 is configured such that, under the action of light, the storage modulus of the second part 22 is approximately 20 kPa, and / or, the crosslinking density of the second part 22 is approximately 2 × 10⁻⁴ mol / cm³.

[0140] When a thermally degradable crosslinking agent is provided, the weight of the thermally degradable crosslinking agent is 0.01-2 parts. For example, the weight of the thermally degradable crosslinking agent can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.

[0141] When the weight of the thermally degradable crosslinking agent is 0.01 parts, the second part 22 is configured such that, under the action of heat, the storage modulus of the second part 22 is approximately less than or equal to 5 kPa, and / or, the crosslinking density of the second part 22 is approximately 0.1 × 10⁻⁴ mol / cm³; when the weight of the thermally degradable crosslinking agent is 1 part, the second part 22 is configured such that, under the action of heat, the storage modulus of the second part 22 is approximately 15 kPa, and / or, the crosslinking density of the second part 22 is approximately 1 × 10⁻⁴ mol / cm³; when the weight of the thermally degradable crosslinking agent is 2 parts, the second part 22 is configured such that, under the action of heat, the storage modulus of the second part 22 is approximately 20 kPa, and / or, the crosslinking density of the second part 22 is approximately 1.5 × 10⁻⁴ mol / cm³.

[0142] When both photodegradable and thermally degradable crosslinking agents are provided, the sum of the weight parts of the photodegradable crosslinking agent and the weight parts of the thermally degradable crosslinking agent is 0.01-2 parts. For example, the sum of the weight parts of the photodegradable crosslinking agent and the weight parts of the thermally degradable crosslinking agent can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.

[0143] When the sum of the weight parts of the photodegradable crosslinking agent and the thermally degradable crosslinking agent is 0.01, the second part 22 is configured such that, under the action of light and heat, the storage modulus of the second part 22 is approximately 5 kPa, and / or, the crosslinking density of the second part 22 is approximately 0.1 × 10⁻⁴ mol / cm³; when the sum of the weight parts of the photodegradable crosslinking agent and the thermally degradable crosslinking agent is 1, the second part 22 is configured such that, under the action of light and heat, the storage modulus of the second part 22 is approximately 15 kPa, and / or, the crosslinking density of the second part 22 is approximately 1 × 10⁻⁴ mol / cm³; when the sum of the weight parts of the photodegradable crosslinking agent and the thermally degradable crosslinking agent is 2, the second part 22 is configured such that, under the action of light, the storage modulus of the second part 22 is approximately 20 kPa, and / or, the crosslinking density of the second part 22 is approximately 1.8 × 10⁻⁴ mol / cm³.

[0144] The raw materials for the adhesive may also include, but are not limited to, acrylate monomers, polar acrylic comonomers, free radical initiators, and thermal crosslinking agents and / or photocrosslinking agents; the acrylate monomers are 80-90 parts by weight, for example, the weight of acrylate monomers may be 82 parts, 84 parts, 85 parts, 86 parts, 88 parts, etc.; the polar acrylic comonomers are 2-15 parts by weight, for example, the weight of polar acrylic comonomers may be 5 parts, 7 parts, 9 parts, 10 parts, 12 parts, etc.; the free radical initiator is 0.01-2 parts by weight, for example, the weight of free radical initiator may be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.; the thermal crosslinking agent is 0.01-5 parts by weight, for example, the weight of the thermal crosslinking agent may be... The amounts can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc., or the weight of the photocrosslinking agent can be 0.01-5 parts. For example, the weight of the photocrosslinking agent can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc. Or, the sum of the weight of the thermal crosslinking agent and the weight of the photocrosslinking agent can be 0.01-5 parts. For example, the sum of the weight of the thermal crosslinking agent and the weight of the photocrosslinking agent can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc.

[0145] In some exemplary embodiments of this disclosure, the acrylate monomer may include, but is not limited to, one, two, or more of linear monofunctional acrylates, branched monofunctional acrylates, and methacrylates. Specifically, the acrylate monomer may include, but is not limited to, one, two, or more of ethyl (meth)acrylate, meth (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. That is, the acrylate monomer may include, but is not limited to, any one of these materials, any two of these materials, any three of these materials, any more of these materials, or all of these materials; these will not be described in detail here.

[0146] In some exemplary embodiments of this disclosure, the polar acrylic comonomer may include, but is not limited to, one, two, or more of acrylic acid, methacrylic acid, and methacrylamide. For example, the polar acrylic comonomer may include, but is not limited to, acrylic acid, methacrylic acid, or methacrylamide; the polar acrylic comonomer may include, but is not limited to, acrylic acid and methacrylic acid; the polar acrylic comonomer may include, but is not limited to, acrylic acid, methacrylic acid, and methacrylamide; or the polar acrylic comonomer may include, but is not limited to, acrylic acid, methacrylic acid, and methacrylamide.

[0147] In some exemplary embodiments of this disclosure, the free radical initiator may include, but is not limited to, a thermal initiator and / or a photoinitiator. That is, the free radical initiator may include a thermal initiator, or a photoinitiator, or a free radical initiator may include both a thermal initiator and a photoinitiator.

[0148] Specifically, thermal initiators may include, but are not limited to, peroxides or azo compounds. A variety of peroxides or azo compounds can be used to initiate thermal polymerization, and these compounds can be used at various temperatures.

[0149] Photoinitiators may include, but are not limited to, hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylphenylformyl)phosphine oxide.

[0150] In some exemplary embodiments of this disclosure, the thermal crosslinking agent is activated during the drying step of preparing the solvent-coated adhesive and is a crosslinking agent that undergoes copolymerization during the polymerization step. The thermal crosslinking agent may include, but is not limited to, one, two, or more of polyfunctional isocyanates, polyfunctional aziridines, and epoxy compounds; that is, the thermal crosslinking agent may include, but is not limited to, any one of these materials, any two of these materials, any multiple of these materials, or all of these materials; these will not be described in detail here.

[0151] In some exemplary embodiments of this disclosure, the photocrosslinker may be a UV-activated crosslinker. The photocrosslinker may include, but is not limited to, non-copolymerized photocrosslinkers and / or copolymerized photocrosslinkers.

[0152] Specifically, the non-copolymer photocrosslinking agent may include, but is not limited to, benzophenone, and the copolymer photocrosslinking agent may include, but is not limited to, acrylic compounds and methacrylic compounds, for example, 4-acryloyloxybenzophenone.

[0153] In some exemplary embodiments of this disclosure, the adhesive may also include, but is not limited to, any one, any two, or any combination of plasticizers, elastomer monomers, molecular weight control agents, and coupling agents. The plasticizer is present in 5-10 parts by weight, for example, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 parts by weight, etc.; the elastomer monomer is present in 3-5 parts by weight, for example, 3.5, 4, 4.5 parts by weight, etc.; the molecular weight control agent is present in 0.01-1 part by weight, for example, 0.05, 0.1, 0.3, 0.5, 0.7, 0.9 parts by weight, etc.; the coupling agent is present in 0.01-1 part by weight, for example, 0.05, 0.1, 0.3, 0.5, 0.7, 0.9 parts by weight, etc.

[0154] Plasticizers can be added to dissolved polymers to lower the glass transition temperature, thereby increasing the flexibility of the adhesive. Specifically, plasticizers can include, but are not limited to, phthalates, such as dibutyl phthalate, dioctyl phthalate, or diisononyl phthalate, etc.

[0155] Elasticity or toughness can be increased by using elastomer monomers, which may include, but are not limited to, polybutadiene or polyisoprene.

[0156] Molecular weight control agents enhance the flowability of adhesives by reducing the molecular weight of polymers, making it easier to fill irregular surfaces or gaps in applications. This improves the adhesive's adaptability during processing, ensuring good bonding performance under varying temperatures and conditions. Molecular weight control agents may include, but are not limited to, n-dodecyl mercaptan and isooctyl mercaptan.

[0157] Coupling agents can be used to ensure that the adhesive maintains sufficient bond strength between the layers within the adhesive, resisting or preventing delamination. Coupling agents can include, but are not limited to, vinyltrimethoxysilane and γ-aminopropyltriethoxysilane.

[0158] Based on the same inventive concept, this disclosure provides an adhesive comprising acrylate monomers, polar acrylic comonomers, free radical initiators, thermal crosslinking agents and / or photocrosslinking agents, and photodegradable crosslinking agents and / or thermally degradable crosslinking agents. The acrylate monomers are present in an amount of 80-90 parts by weight; the polar acrylic comonomers are present in an amount of 2-15 parts by weight; the free radical initiator is present in an amount of 0.01-2 parts by weight; the thermal crosslinking agent is present in an amount of 0.01-5 parts by weight, or the photocrosslinking agent is present in an amount of 0.01-5 parts by weight, or the sum of the thermal crosslinking agent and the photocrosslinking agent is 0.01-5 parts by weight; the photodegradable crosslinking agent is present in an amount of 0.01-2 parts by weight, or the sum of the photodegradable crosslinking agent and the thermally degradable crosslinking agent is 0.01-2 parts by weight.

[0159] For example, the weight parts of acrylate monomers can be 82 parts, 84 parts, 85 parts, 86 parts, 88 parts, etc.; the weight parts of polar acrylic comonomers can be 5 parts, 7 parts, 9 parts, 10 parts, 12 parts, etc.; the weight parts of free radical initiators can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.; the weight parts of thermal crosslinking agents can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc.; or, the weight parts of photocrosslinking agents can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc.; or, light... The sum of the weight parts of the degradable crosslinking agent and the thermally degradable crosslinking agent can be 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc.; the weight parts of the photodegradable crosslinking agent can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.; or the weight parts of the thermally degradable crosslinking agent can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.; or the sum of the weight parts of the photodegradable crosslinking agent and the thermally degradable crosslinking agent can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, etc.

[0160] In some exemplary embodiments of this disclosure, the acrylate monomer may include, but is not limited to, one, two, or more of linear monofunctional acrylates, branched monofunctional acrylates, and methacrylates. Specifically, the acrylate monomer may include, but is not limited to, one, two, or more of ethyl (meth)acrylate, meth (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. That is, the acrylate monomer may include, but is not limited to, any one of these materials, any two of these materials, any three of these materials, any more of these materials, or all of these materials; these will not be described in detail here.

[0161] In some exemplary embodiments of this disclosure, the polar acrylic comonomer may include, but is not limited to, one, two, or more of acrylic acid, methacrylic acid, and methacrylamide. For example, the polar acrylic comonomer may include, but is not limited to, acrylic acid, methacrylic acid, or methacrylamide; the polar acrylic comonomer may include, but is not limited to, acrylic acid and methacrylic acid; the polar acrylic comonomer may include, but is not limited to, acrylic acid, methacrylic acid, and methacrylamide; or the polar acrylic comonomer may include, but is not limited to, acrylic acid, methacrylic acid, and methacrylamide.

[0162] In some exemplary embodiments of this disclosure, the free radical initiator may include, but is not limited to, a thermal initiator and / or a photoinitiator. That is, the free radical initiator may include a thermal initiator, or a photoinitiator, or a free radical initiator may include both a thermal initiator and a photoinitiator.

[0163] Specifically, thermal initiators may include, but are not limited to, peroxides or azo compounds. A variety of peroxides or azo compounds can be used to initiate thermal polymerization, and these compounds can be used at various temperatures.

[0164] Photoinitiators may include, but are not limited to, hydroxycyclohexylphenyl ketone, phenyl bis(2,4,6-trimethylphenylformyl)phosphine oxide, etc.

[0165] In some exemplary embodiments of this disclosure, the thermal crosslinking agent is activated during the drying step of preparing the solvent-coated adhesive and is a crosslinking agent that undergoes copolymerization during the polymerization step. The thermal crosslinking agent may include, but is not limited to, one, two, or more of polyfunctional isocyanates, polyfunctional aziridines, and epoxy compounds; that is, the thermal crosslinking agent may include, but is not limited to, any one of these materials, any two of these materials, any multiple of these materials, or all of these materials; these will not be described in detail here.

[0166] In some exemplary embodiments of this disclosure, the photocrosslinker may be a UV-activated crosslinker. The photocrosslinker may include, but is not limited to, non-copolymerized photocrosslinkers and / or copolymerized photocrosslinkers.

[0167] Specifically, the non-copolymer photocrosslinking agent may include, but is not limited to, benzophenone, and the copolymer photocrosslinking agent may include, but is not limited to, acrylic compounds and methacrylic compounds, for example, 4-acryloyloxybenzophenone.

[0168] In some exemplary embodiments of this disclosure, the photodegradable crosslinking agent may include, but is not limited to, one, two, or three of the following: coumarin-based crosslinking agents, azobenzene-based crosslinking agents, and O-nitrophenyl-based crosslinking agents. For example, the photodegradable crosslinking agent may include, but is not limited to, a coumarin-based crosslinking agent, azobenzene-based crosslinking agent, or O-nitrophenyl-based crosslinking agent; the photodegradable crosslinking agent may include, but is not limited to, a coumarin-based crosslinking agent and azobenzene-based crosslinking agent; the photodegradable crosslinking agent may include, but is not limited to, azobenzene-based crosslinking agent and O-nitrophenyl-based crosslinking agent; the photodegradable crosslinking agent may include, but is not limited to, a coumarin-based crosslinking agent, azobenzene-based crosslinking agent, and O-nitrophenyl-based crosslinking agent.

[0169] Specifically, coumarin-based crosslinking agents may include, but are not limited to, one, two, or more of the following: coumarin-6-based crosslinking agents, coumarin diacrylates, coumarin-functionalized polyvinyl alcohol (PVA), coumarin-based dendritic polymers, and photo-severable coumarin derivatives. For example, coumarin-based crosslinking agents may include, but are not limited to, coumarin-6-based crosslinking agents, coumarin diacrylates, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymers, or photo-severable coumarin derivatives; coumarin-based crosslinking agents may also include, but are not limited to, any two of the following: coumarin-6-based crosslinking agents, coumarin diacrylates, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymers, and photo-severable coumarin derivatives, which will not be listed individually here; coumarin-based crosslinking agents may also include, but are not limited to, coumarin-6-based crosslinking agents, coumarin diacrylates, and coumarin-functionalized... The coumarin-based crosslinking agent may be any three of the following: polyvinyl alcohol, coumarin-based dendritic polymers, and photo-severable coumarin derivatives, without further explanation. The coumarin-based crosslinking agent may also include, but is not limited to, any four of the following: coumarin-6-based crosslinking agent, coumarin diacrylate, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymers, and photo-severable coumarin derivatives, without further explanation.

[0170] Specifically, the crosslinking agent based on azobenzene can be, but is not limited to, one, two, or more of the following: azobenzene diacrylate, polyethylene glycol (PEG) containing azobenzene, azobenzene-based dendritic polymers, azobenzene derivatives containing azido groups, and azobenzene-terminated polyesters. That is, the crosslinking agent based on azobenzene can be, but is not limited to, any one of the following: azobenzene diacrylate, polyethylene glycol containing azobenzene, azobenzene-based dendritic polymers, azobenzene derivatives containing azido groups, and azobenzene-terminated polyesters; it can also be, but is not limited to, any two of these materials; it can also be, but is not limited to, any three or four of these materials; or it can include all of them. These will not be listed individually here.

[0171] Specifically, the crosslinking agent based on O-nitrophenyl can include, but is not limited to, one, two, or more of the following: O-nitrophenyl 1,6-hexanediamine, O-nitrophenyl methacrylate, O-nitrophenyl-modified polyvinyl alcohol (PVA), polymers of O-nitrophenyl derivatives (e.g., poly(N-isopropylacrylamide)), and dendritic polymers based on O-nitrophenyl. That is, the crosslinking agent based on O-nitrophenyl can include, but is not limited to, any one of the following: O-nitrophenyl 1,6-hexanediamine, O-nitrophenyl methacrylate, O-nitrophenyl-modified polyvinyl alcohol, polymers of O-nitrophenyl derivatives, and dendritic polymers based on O-nitrophenyl; it can also include, but is not limited to, any two of these materials; it can also include, but is not limited to, any three or four of these materials; or it can include all of them. These will not be listed individually here.

[0172] In some exemplary embodiments of this disclosure, the thermally degradable crosslinking agent may include, but is not limited to, melamine, difunctional polyether, difunctional polyester, and one, two, or more compounds containing amino, hydroxyl, or carboxylic acid functional groups. That is, the thermally degradable crosslinking agent may include, but is not limited to, any one of melamine, difunctional polyether, difunctional polyester, and compounds containing amino, hydroxyl, or carboxylic acid functional groups, or may include, but is not limited to, any two or three of these materials, or may include all of them; however, each will not be described in detail here.

[0173] Specifically, bifunctional polyethers may include, but are not limited to, dihydroxy polyethers. Bifunctional polyesters may include, but are not limited to, polyethylene glycol diacrylate and hexanediol diacrylate. Compounds containing amino, hydroxyl, or carboxylic acid functional groups may include, but are not limited to, one, two, or more of diethylenetriamine, butanetetracarboxylic acid, maleic anhydride, succinic anhydride, 2,4-diisocyanate, and 2,6-diisocyanate.

[0174] In this disclosure, the storage modulus and crosslinking density of the first portion 21 and the second portion 22 subsequently formed by the adhesive in each embodiment were tested, as shown in the table below:

[0175] In some exemplary embodiments of this disclosure, the adhesive may also include, but is not limited to, any one, any two, or any combination of plasticizers, elastomer monomers, molecular weight control agents, and coupling agents. The plasticizer is present in 5-10 parts by weight, for example, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, etc.; the elastomer is present in 3-5 parts by weight, for example, 3.5, 4, 4.5, etc.; the molecular weight control agent is present in 0.01-1 parts by weight, for example, 0.05, 0.1, 0.3, 0.5, 0.7, 0.9, etc.; the coupling agent is present in 0.01-1 parts by weight, for example, 0.05, 0.1, 0.3, 0.5, 0.7, 0.9, etc.

[0176] Plasticizers can be added to dissolved polymers to lower the glass transition temperature, thereby increasing the flexibility of the adhesive. Specifically, plasticizers can include, but are not limited to, phthalates, such as dibutyl phthalate, dioctyl phthalate, or diisononyl phthalate, etc.

[0177] Elasticity or toughness can be increased by using elastomer monomers, which may include, but are not limited to, polybutadiene or polyisoprene.

[0178] Molecular weight control agents enhance the flowability of adhesives by reducing the molecular weight of polymers, making it easier to fill irregular surfaces or gaps in applications. This improves the adhesive's adaptability during processing, ensuring good bonding performance under varying temperatures and conditions. Molecular weight control agents may include, but are not limited to, n-dodecyl mercaptan and isooctyl mercaptan.

[0179] Coupling agents can be used to ensure that the adhesive maintains sufficient bond strength between the layers within the adhesive, resisting or preventing delamination. Coupling agents can include, but are not limited to, vinyltrimethoxysilane and γ-aminopropyltriethoxysilane.

[0180] When the adhesive includes any one, two, or more of the following: plasticizer, elastomer monomer, molecular weight control agent, and coupling agent, the storage modulus and crosslinking density of the first part 21 and the second part 22 formed by the adhesive are not significantly affected. Therefore, the values ​​of the examples in which the adhesive includes plasticizer, elastomer monomer, molecular weight control agent, and coupling agent are basically the same as those in the examples provided in the table above, and will not be repeated here.

[0181] Peel strength tests were conducted on the adhesive. After bonding with the bonded layer, the 180° peel strength between the adhesive and the bonded layer was greater than or equal to 1700 gf / in at 25 degrees Celsius, greater than or equal to 1000 gf / in at 65 degrees Celsius, and greater than or equal to 700 gf / in at 85 degrees Celsius.

[0182] Static bending tests were conducted on the adhesive after bonding the first cover plate (UTG) and the second cover plate (PET material) to both sides. The test duration was 240 hours, the bending radius was R1.5 mm, and the adhesive thickness was 50 micrometers. The adhesive met the requirements and passed the tests at -20℃, 25℃, and 85℃ (relative humidity: 85RH). Dynamic bending tests were also conducted on the adhesive after bonding the first cover plate (UTG) and the second cover plate (PET material) to both sides. The test duration was 400,000 cycles, the bending radius was R1.5 mm, and the adhesive thickness was 50 micrometers. The adhesive met the requirements and passed the tests at -20℃, 25℃, 60℃ (relative humidity: 90RH), and 85℃ (relative humidity: 85RH).

[0183] The preparation method of the adhesive may include: first, preparing the above-mentioned raw materials and ethyl acetate solvent in the specified weight proportions; mixing the acrylate monomer, free radical initiator and ethyl acetate solvent in a glass reaction flask according to the formula ratio; then adding the polar acrylic copolymer monomer; purging the glass reaction flask with nitrogen for 2-3 minutes to remove oxygen; and then sealing the glass reaction flask; placing the glass reaction flask in a 60°C constant temperature water bath and rotating it at 30-50 rpm for 24 hours; adding the photodegradable crosslinking agent and / or the thermally degradable crosslinking agent, as well as the thermal crosslinking agent and / or the photocrosslinking agent, and continuing to rotate and stir for 2 hours to uniformly disperse it into a reaction solution.

[0184] The reaction solution formed above is uniformly coated onto the siliconized PET release film, for example, by roller coating, spraying, doctor blade coating, calendering, etc. The coating thickness (typically 25μm-100μm) is controlled using a precision coater or doctor blade, with a coating speed of 3-5 m / min. The coating environment temperature is 25±2℃, and the relative humidity is 45±5%. Then, a curing process is performed, specifically, treating in an oven at approximately 70℃ for 24 hours, followed by natural cooling to room temperature to form an adhesive material layer. Finally, a layer of siliconized PET release film is placed on top of the formed adhesive material layer. This film can be cut to the required size to form a spare adhesive film, and then vacuum-packed and sealed for storage.

[0185] Based on the same inventive concept, this disclosure provides an example embodiment of a method for fabricating a flexible display module. Referring to FIG10, the fabrication method may include the following steps:

[0186] Step S10: Provide a flexible display panel 1, the flexible display panel 1 having a non-edge region 11 and an edge region 12 surrounding the non-edge region 11.

[0187] Step S20: An adhesive material layer group is formed on the display side of the flexible display panel 1, and at least a portion of the adhesive material layer group located in the edge region 12 is irradiated and / or heated to form a second part 22. The adhesive material layer group that is not irradiated and heated forms a first part 21. The first part 21 is located at least in the non-edge region 11, and the second part 22 is located in the edge region 12. The storage modulus of the second part 22 is less than the storage modulus of the first part 21, and / or the crosslinking density of the second part 22 is less than the crosslinking density of the first part 21.

[0188] The specific structure of the flexible display panel 1 has been described in detail above, so it will not be repeated here.

[0189] An adhesive material layer is formed on the display side of the flexible display panel 1.

[0190] Specifically, when preparing a foldable display panel, if a first adhesive layer 2a and a first cover layer 31 are provided, a PET release film on the prepared adhesive film can be peeled off, and then the adhesive material layer is bonded to the display side of the flexible display panel 1. Another PET release film is then peeled off, and the first cover layer 31 is then applied. If the adhesive material layer includes a photodegradable crosslinking agent, the adhesive material layer located in the edge bending region 121 is irradiated to form a second portion 22. If the adhesive material layer includes a thermally degradable crosslinking agent, the adhesive material layer located in the edge bending region 121 is heated to form the second portion 22. If the adhesive material layer includes both a photodegradable crosslinking agent and a thermally degradable crosslinking agent, the adhesive material layer located in the edge bending region 121 is irradiated and heated to form the second portion 22, thus placing the second portion 22 in the edge bending region 121. Other adhesive material layers that have not been exposed to light and heat form a first portion 21, such that the first portion 21 is located at least in the non-edge region 11 and the edge non-bending region 122; and such that the energy storage modulus of the second portion 22 is less than the energy storage modulus of the first portion 21, and / or, the crosslinking density of the second portion 22 is less than the crosslinking density of the first portion 21.

[0191] In the fabrication of the roll-up display panel, when the adhesive material layer includes a photodegradable crosslinking agent, the adhesive material layer located in the roll-up bending region 123 is irradiated to form a second portion 22; when the adhesive material layer includes a thermally degradable crosslinking agent, the adhesive material layer located in the roll-up bending region 123 is heated to form the second portion 22; when the adhesive material layer includes both a photodegradable crosslinking agent and a thermally degradable crosslinking agent, the adhesive material layer located in the roll-up bending region 123 is both irradiated and heated to form the second portion 22; thus, the second portion 22 is located in the roll-up bending region 123. Other adhesive material layers that are not irradiated or heated form a first portion 21, such that the first portion 21 is located at least in the non-edge region 11 and the roll-up non-bending region 124; and the storage modulus of the second portion 22 is less than the storage modulus of the first portion 21, and / or, the crosslinking density of the second portion 22 is less than the crosslinking density of the first portion 21. Then, the first cover plate layer 31 is applied.

[0192] Of course, in some other example embodiments of this disclosure, light and / or heating may be applied first, and then the first cover layer 31 may be applied.

[0193] With two adhesive layers (first adhesive layer 2a and second adhesive layer 2b), a first cover layer 31, and a second cover layer 32, a PET release film can be peeled off from the prepared adhesive film, and then the adhesive material layer is bonded to the display side of the flexible display panel 1. Another PET release film is peeled off to form the first adhesive material layer, and then the first cover layer 31 is applied. Next, a PET release film is peeled off from the other prepared adhesive film, and then the adhesive material layer is bonded to the side of the first cover layer 31 opposite to the flexible display panel 1. Another PET release film is peeled off to form the second adhesive material layer. The first and second adhesive material layers constitute an adhesive material layer assembly. Finally, the second cover layer 32 is applied.

[0194] When the adhesive layer assembly includes a photodegradable crosslinking agent, the adhesive layer assembly located in the edge bending region 121 is irradiated to form a second portion 22; when the adhesive layer assembly includes a thermally degradable crosslinking agent, the adhesive layer assembly located in the edge bending region 121 is heated to form a second portion 22; when the adhesive layer assembly includes both a photodegradable crosslinking agent and a thermally degradable crosslinking agent, the adhesive layer assembly located in the edge bending region 121 is both irradiated and heated to form a second portion 22; such that the second portion 22 is located in the edge bending region 121. Other adhesive layer assemblies that have not been irradiated or heated form a first portion 21, such that the first portion 21 is located at least in the non-edge region 11 and the edge non-bending region 122; and such that the storage modulus of the second portion 22 is less than the storage modulus of the first portion 21, and / or, the crosslinking density of the second portion 22 is less than the crosslinking density of the first portion 21.

[0195] In the fabrication of the roll-up display panel, when the adhesive layer group includes a photodegradable crosslinking agent, the adhesive layer group located in the roll-up bending region 123 is irradiated to form a second portion 22; when the adhesive layer group includes a thermally degradable crosslinking agent, the adhesive layer group located in the roll-up bending region 123 is heated to form the second portion 22; when the adhesive layer group includes both a photodegradable crosslinking agent and a thermally degradable crosslinking agent, the adhesive layer group located in the roll-up bending region 123 is both irradiated and heated to form the second portion 22; thus, the second portion 22 is located in the roll-up bending region 123. Other adhesive layer groups that have not been irradiated or heated form a first portion 21, such that the first portion 21 is located at least in the non-edge region 11 and the roll-up non-bending region 124; and the storage modulus of the second portion 22 is less than the storage modulus of the first portion 21, and / or, the crosslinking density of the second portion 22 is less than the crosslinking density of the first portion 21. Then, a second cover layer 32 is applied.

[0196] Of course, in some other example embodiments of this disclosure, light and / or heating may be performed first, and then the second cover layer 32 may be applied.

[0197] Furthermore, the adhesive layer can be the reaction liquid formed above, which can be coated to form a thin film, for example, by roller coating, spraying, doctor blade coating, calendering coating, etc., and then cured.

[0198] Heating methods can include infrared heating, microwave heating, and laser heating. Infrared heating effectively provides heat, accelerates the reverse reaction, and reduces cross-linking density. Microwave heating enables uniform heating within the second part 22, thereby achieving a rapid transition to a softened state. Laser heating can provide highly focused heat, rapidly breaking cross-linking bonds within a small area and reducing cross-linking density.

[0199] It should be noted that although the steps of the flexible display module fabrication method of this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0200] Based on the same inventive concept, this disclosure provides an example embodiment of a flexible display device. Referring to FIG11, the flexible display device may include the flexible display module 10 described in any of the above-described embodiments. The specific structure of the flexible display module 10 has been described in detail above, and therefore will not be repeated here.

[0201] Referring to Figure 11, the flexible display device can be a foldable display device. The two flat parts of the flexible display module 10 are bonded to the middle frame 5 by adhesive 6, and the two relatively flat parts of the bent part of the flexible display module 10 are also bonded to the wing plate 7 by adhesive 6.

[0202] The specific type of flexible display device is not particularly limited; any type of flexible display device commonly used in the field is acceptable, such as mobile devices like mobile phones, wearable devices like watches, VR devices, etc. Those skilled in the art can make the appropriate selection based on the specific purpose of the display device, which will not be elaborated here.

[0203] It should be noted that, in addition to the array substrate, the flexible display device also includes other necessary components and parts. Taking the display as an example, these include, for instance, the casing, circuit board, power cord, etc. Those skilled in the art can supplement these components according to the specific usage requirements of the flexible display device, and will not be elaborated here.

[0204] Compared with the prior art, the beneficial effects of the flexible display device provided by the exemplary embodiments of the present invention are the same as the beneficial effects of the array substrate provided by the above exemplary embodiments, and will not be repeated here.

[0205] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A flexible display module, wherein, include: A flexible display panel having a non-edge region and an edge region surrounding the non-edge region; An adhesive layer assembly is disposed on the display side of the flexible display panel. The adhesive layer assembly includes a first portion and a second portion. The first portion is disposed at least in the non-edge region, and the second portion is disposed in the edge region. The adhesive layer assembly includes an adhesive, which includes a photodegradable crosslinking agent and / or a thermally degradable crosslinking agent. The second portion is configured such that, under the action of light and / or heat, the storage modulus of the second portion is less than the storage modulus of the first portion, and / or the crosslinking density of the second portion is less than the crosslinking density of the first portion.

2. The flexible display module according to claim 1, wherein, The energy storage modulus of the second part is less than or equal to 20 kPa, the energy storage modulus of the first part is greater than or equal to 40 kPa and less than or equal to 200 kPa, and / or the crosslinking density of the second part is less than or equal to 0.05 mmol / cm^3, and the crosslinking density of the first part is greater than or equal to 0.1 mmol / cm^3 and less than or equal to 1 mmol / cm^3.

3. The flexible display module according to claim 1, wherein, Bubbles are formed within the adhesive layer group in the edge region, and the maximum size of the bubbles is less than or equal to 50 μm.

4. The flexible display module according to claim 1, wherein, The flexible display panel is a foldable display panel, and the edge region includes an edge bending region and an edge non-bending region. The second part is disposed in the edge bending region, and the first part is also disposed in the edge non-bending region. Alternatively, the flexible display panel is a rollable display panel, and the edge region includes a rollable bending region and a rollable non-bending region, with the second part located in the rollable bending region and the first part also located in the rollable non-bending region.

5. The flexible display module according to claim 1, wherein, The adhesive layer assembly includes a first adhesive layer, and the flexible display module further includes: The first cover plate layer is bonded to the side of the first adhesive layer opposite to the flexible display panel.

6. The flexible display module according to claim 1, wherein, The adhesive layer assembly includes a first adhesive layer and a second adhesive layer, and the flexible display module further includes: A first cover plate layer is bonded to the side of the first adhesive layer opposite to the flexible display panel, and a second adhesive layer is bonded to the side of the first cover plate layer opposite to the flexible display panel. The second cover layer is bonded to the side of the second adhesive layer opposite to the flexible display panel.

7. The flexible display module according to claim 6, wherein, The orthographic projection of the first cover layer on the flexible display panel is located within the orthographic projection of the adhesive layer assembly on the flexible display panel, and there is a non-zero gap between the edge line of the orthographic projection of the first cover layer on the flexible display panel and the edge line of the orthographic projection of the adhesive layer assembly on the flexible display panel, so that the portions of the first adhesive layer and the second adhesive layer protruding from the first cover layer are connected as one unit.

8. The flexible display module according to claim 7, wherein, The orthographic projection of the second part on the flexible display panel overlaps with the orthographic projection of the first cover layer on the flexible display panel.

9. The flexible display module according to claim 7, wherein, The orthographic projection of the first cover layer on the flexible display panel is located within the orthographic projection of the second cover layer on the flexible display panel, and there is a non-zero gap between the edge line of the orthographic projection of the first cover layer on the flexible display panel and the edge line of the orthographic projection of the second cover layer on the flexible display panel.

10. The flexible display module according to any one of claims 1 to 9, wherein, The photodegradable crosslinking agent includes one, two, or three of the following: coumarin-based crosslinking agents, azobenzene-based crosslinking agents, and O-nitrophenyl-based crosslinking agents.

11. The flexible display module according to claim 10, wherein, The coumarin-based crosslinking agent includes one, two, or more of the following: coumarin-6-based crosslinking agent, coumarin diacrylate, coumarin-functionalized polyvinyl alcohol, coumarin-based dendritic polymer, and photo-severable coumarin derivative.

12. The flexible display module according to claim 10, wherein, The azobenzene-based crosslinking agent includes one, two, or more of the following: azobenzene diacrylate, azobenzene-containing polyethylene glycol, azobenzene-based dendritic polymer, azobenzene derivatives containing azido groups, and azobenzene-terminated polyesters.

13. The flexible display module according to claim 10, wherein, The O-nitrophenyl-based crosslinking agent includes one, two, or more of the following: O-nitrophenyl 1,6-hexanediamine, O-nitrophenyl methacrylate, O-nitrophenyl-modified polyvinyl alcohol, polymers of O-nitrophenyl derivatives, and dendritic polymers based on O-nitrophenyl.

14. The flexible display module according to any one of claims 1 to 9, wherein, The thermally degradable crosslinking agent includes one, two, or more of the following: melamine, bifunctional polyether, bifunctional polyester, and compounds containing amino, hydroxyl, or carboxylic acid functional groups.

15. The flexible display module according to claim 14, wherein, The bifunctional polyether includes dihydroxy polyether.

16. The flexible display module according to claim 14, wherein, The compounds containing amino, hydroxyl, or carboxylic acid functional groups include one, two, or more of diethylenetriamine, butanetetracarboxylic acid, maleic anhydride, succinic anhydride, 2,4-diisocyanate, and 2,6-diisocyanate.

17. The flexible display module according to any one of claims 1 to 9, wherein, The photodegradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the thermally degradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the sum of the weight of the photodegradable crosslinking agent and the weight of the thermally degradable crosslinking agent is 0.01-2 parts by weight. The adhesive also includes the following raw materials: Acrylic ester monomer, 80-90 parts by weight; Polar acrylic comonomer, in parts by weight of 2-15; Free radical initiator, in parts by weight of 0.01-2 parts; A thermal crosslinking agent and / or a photocrosslinking agent, wherein the thermal crosslinking agent is present in a weight ratio of 0.01-5 parts; or the photocrosslinking agent is present in a weight ratio of 0.01-5 parts; or the sum of the weight ratios of the thermal crosslinking agent and the photocrosslinking agent is 0.01-5 parts.

18. The flexible display module according to claim 17, wherein, The acrylate monomers include one, two, or more of linear monofunctional acrylates, branched monofunctional acrylates, and methacrylates.

19. The flexible display module according to claim 17, wherein, The polar acrylic comonomer includes one, two, or more of acrylic acid, methacrylic acid, and methacrylamide.

20. The flexible display module according to claim 17, wherein, The free radical initiator includes thermal initiators and / or photoinitiators.

21. The flexible display module according to claim 20, wherein, The thermal initiator includes peroxides or azo compounds.

22. The flexible display module according to claim 17, wherein, The thermal crosslinking agent includes one, two, or more of the following: polyfunctional isocyanates, polyfunctional aziridines, and epoxy compounds.

23. The flexible display module according to claim 17, wherein, The photocrosslinking agent includes non-copolymerized photocrosslinking agents and / or copolymerized photocrosslinking agents.

24. The flexible display module according to claim 1, wherein, The adhesive also includes the following raw materials: Plasticizer, 5-10 parts by weight; And / or, 3-5 parts by weight of elastomer monomer; And / or, a molecular weight control agent, in parts by weight of 0.01-1; And / or, coupling agent, in parts by weight of 0.1-3 parts.

25. An adhesive, wherein, The raw materials for the adhesive include: Acrylic ester monomer, 80-90 parts by weight; Polar acrylic comonomer, in parts by weight of 2-15; Free radical initiator, in parts by weight of 0.01-2 parts; A thermal crosslinking agent and / or a photocrosslinking agent, wherein the thermal crosslinking agent is present in a weight ratio of 0.01-5 parts; or the photocrosslinking agent is present in a weight ratio of 0.01-5 parts; or the sum of the weight ratios of the thermal crosslinking agent and the photocrosslinking agent is 0.01-5 parts. The crosslinking agent is photodegradable and / or thermally degradable, wherein the photodegradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the thermally degradable crosslinking agent is present in an amount of 0.01-2 parts by weight; or the combined amount of the photodegradable crosslinking agent and the thermally degradable crosslinking agent is 0.01-2 parts by weight.

26. A method for manufacturing a flexible display module, wherein, include: A flexible display panel is provided, the flexible display panel having a non-edge region and an edge region surrounding the non-edge region; An adhesive material layer group is formed on the display side of the flexible display panel, and at least a portion of the adhesive material layer group located in the edge region is irradiated and / or heated to form a second part, while the adhesive material layer group that is not irradiated and heated forms a first part. The first part is located at least in the non-edge region, and the second part is located in the edge region. The storage modulus of the second part is less than that of the first part, and / or the crosslinking density of the second part is less than that of the first part.

27. A flexible display device, wherein, include: The flexible display module according to any one of claims 1-24.

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