Foldable screen apparatus and electronic device

Abstract

The present application relates to the technical field of foldable screens. Disclosed are a foldable screen apparatus and an electronic device. The foldable screen apparatus comprises: a flexible cover plate, a first adhesive layer, a display layer, a second adhesive layer and a support layer which are stacked in sequence, wherein a plurality of first microsphere particles are provided in the first adhesive layer, and in the first adhesive layer, the plurality of first microsphere particles are distributed in a single layer; each first microsphere particle comprises a first core and a first shell; and when the first microsphere particle is subjected to an external force, the elastic deformation amount of the first shell is greater than that of the first core.

Description

Foldable screen devices and electronic devices

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510492230.2, filed in China on April 18, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of foldable screen technology, specifically to a foldable screen device and an electronic device. Background Technology

[0004] In related technologies, foldable screens typically consist of a flexible cover plate, an upper optical clear adhesive (OCA) layer, a polarizer, a display layer, a lower OCA layer, and a supporting backplate from top to bottom. Among these, the flexible cover plate, display layer, and supporting backplate are relatively rigid materials, resulting in high interlayer stress during bending. Therefore, soft, substrate-free OCA is needed for bonding to buffer the interlayer stress and reduce damage to the display layer.

[0005] In foldable screens, the rigid layers undergo relative displacement during bending, with the stress concentration being highest at the center of the bend. At this point, the OCA adhesive layer experiences elastic deformation under tensile / compressive stress. After repeated bending and unfolding, the OCA adhesive in the center of the screen begins to creep and thin, its elastic recovery deteriorates, and irreversible creep gradually occurs, resulting in deep creases on the screen. Therefore, in related technologies, foldable screens are prone to crease formation at the folding point.

[0006] Application content

[0007] This application provides a foldable screen device and an electronic device that can mitigate the formation of creases in the foldable screen device.

[0008] In a first aspect, this application provides a foldable screen device, comprising: a flexible cover plate, a first adhesive layer, a display layer, a second adhesive layer and a support layer stacked sequentially;

[0009] The first adhesive layer contains a plurality of first microspheres, which are distributed in a single layer within the first adhesive layer.

[0010] The first microsphere includes a first core and a first shell. When the first microsphere is subjected to an external force, the elastic deformation of the first shell is greater than that of the first core.

[0011] Secondly, this application provides an electronic device including the foldable screen device described in the first aspect.

[0012] In this embodiment, by setting multiple first microspheres in the first adhesive layer, during the folding process of the foldable screen device, the elastic deformation of the first outer shell is greater than that of the first core when the first microspheres are subjected to external force. That is, the first core is not easily deformed and can form a thickness support, thereby making the first adhesive layer less prone to fatigue thinning. At the same time, the elastic deformation of the first outer shell is relatively large when the first microspheres are subjected to external force, meaning the first outer shell is relatively easy to undergo elastic deformation. Thus, when the foldable screen device is unfolded, the first outer shell has a certain degree of resilience, which can assist the adhesive layer in undergoing elastic deformation, thereby effectively reducing the formation of creases. In addition, the microsphere structure can improve the overall rigidity of the screen, ensuring that the core display layer will not be directly hit during the drop ball and pen test, thereby greatly enhancing the screen reliability. Furthermore, since the first adhesive layer is located on the display side of the foldable screen device, by distributing the plurality of first microspheres in a single layer within the first adhesive layer, it can be ensured that there is only one layer of first microspheres in the first adhesive layer, thus avoiding the problem of a significant reduction in the overall display effect of the foldable screen device due to the presence of more than two layers of first microspheres. Attached Figure Description

[0013] Figure 1 is a cross-sectional view of the folding screen device provided in an embodiment of this application;

[0014] Figure 2 is a partial schematic diagram of Figure 1;

[0015] Figure 3 is a comparative schematic diagram of the adhesive layer with added microspheres and the adhesive layer without added microspheres in a folded state.

[0016] Figure 4 is a comparative diagram of the drop pen test between a foldable screen device with added microspheres and a foldable screen device without added microspheres.

[0017] Figure 5 is a schematic diagram of the internal structure of the first adhesive layer in an embodiment of this application;

[0018] Figure 6 is a schematic diagram comparing the light propagation process when the adhesive layer has multiple layers of microspheres and when it has a single layer of microspheres.

[0019] Figure 7 is a schematic diagram of the internal structure of the second adhesive layer in an embodiment of this application. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0022] The following description, in conjunction with the accompanying drawings, details a foldable screen device and electronic device provided in this application through specific embodiments and application scenarios.

[0023] Please refer to Figures 1 and 2. This application provides a folding screen device, which includes: a flexible cover plate 100, a first adhesive layer 200, a display layer 300, a second adhesive layer 400, and a support layer 500 stacked sequentially.

[0024] The first adhesive layer 200 contains a plurality of first microspheres 600, which are distributed in a single layer within the first adhesive layer 200.

[0025] It is understandable that the aforementioned foldable screen device can serve as the screen module for various foldable screen devices.

[0026] The first microsphere 600 includes a first core 610 and a first outer shell 620. When the first microsphere 600 is subjected to an external force, the elastic deformation of the first outer shell 620 is greater than the elastic deformation of the first core 610.

[0027] The aforementioned first microsphere particle 600 can be a core-shell structure. A core-shell structure refers to a structure in which a core is composed of micrometer- or nanometer-sized particles, and one or more layers of uniform heterogeneous or homogeneous material are coated onto the core to form an outer shell. The core and outer shell are connected by electrostatic or chemical bonding. In this embodiment, the first microsphere particle 600 can be a core-shell structure formed by micrometer-sized particles connected to a heterogeneous outer shell by chemical bonding.

[0028] In this context, both the first adhesive layer 200 and the second adhesive layer 400 can be OCA adhesive layers.

[0029] The aforementioned single-layer distribution of the plurality of first microspheres 600 in the first adhesive layer 200 can be interpreted as follows: along the thickness direction of the first adhesive layer 200, the number of layers of the first microspheres 600 is only one, that is, there are no stacked layers of the first microspheres 600 in the thickness direction of the first adhesive layer 200. The distance between different first microspheres 600 and the flexible cover plate 100 layer can be the same or different. For example, referring to Figure 2, the plurality of first microspheres 600 can be relatively uniformly distributed in different regions of the first adhesive layer 200.

[0030] It is understood that the aforementioned flexible cover plate 100, display layer 300 and support layer 500 can be flexible cover plate 100, display layer 300 and support layer 500 in various types of displays in the related art.

[0031] The first core 610 and the first outer shell 620 are connected by chemical bonds.

[0032] The external force acting on the first microsphere particle 600 can include various external forces that may occur during the manufacturing and normal use of the electronic device. For example, the external force could be the squeezing force exerted by the first adhesive layer 200 during the folding process of the electronic device. Alternatively, the external force could be the impact force experienced during a ball-dropping pen test.

[0033] In some embodiments of this application, the first outer shell 620 can be made of an elastic material, while the first core 610 can be made of a rigid material that is not easily deformed. Thus, when the first microsphere 600 is subjected to external force, the first outer shell 620 can undergo elastic deformation, while the first core 610 hardly deforms. For example, in some embodiments of this application, the material of the first outer shell 620 can be polymethyl methacrylate (PMMA), and the material of the first core 610 can be rigid silica, polystyrene (PS), or rigid PMMA, etc.

[0034] In this embodiment, by setting multiple first microspheres 600 in the first adhesive layer 200, during the folding process of the folding screen device, when the first microspheres 600 are subjected to external force, the elastic deformation of the first outer shell 620 is greater than that of the first core 610, that is, the first core 610 is not easily deformed and can form a thickness support effect, thereby making the first adhesive layer 200 less prone to fatigue thinning. For example, please refer to Figure 3(a), which is a schematic diagram of the adhesive layer in a folded state when microspheres are added, and Figure 3(b), which is a schematic diagram of the adhesive layer in a folded state when no microspheres are added. As can be seen from Figures 3(a) and 3(b), the thickness of the adhesive layer with added microspheres in the folded state at the folded position will be greater than that of the adhesive layer without added microspheres in the folded state at the folded position. The notice states that, due to the relatively large elastic deformation of the first outer shell 620 when the first microsphere particle 600 is subjected to external force, the first outer shell 620 is relatively prone to elastic deformation. Therefore, when the foldable screen device unfolds, the first outer shell 620, possessing a certain degree of resilience, can assist the adhesive layer in undergoing elastic deformation, effectively mitigating crease formation. Simultaneously, the microsphere structure improves the overall rigidity of the screen (see Figure 4(b)), ensuring that the ball drop test will not directly impact the core display layer 300, thus greatly enhancing screen reliability. Conversely, as shown in Figure 4(a), when no microsphere particles are added to the adhesive layer, the ball drop test will easily result in direct impact on the core display layer 300. Furthermore, since the first adhesive layer 200 is located on the display side of the folding screen device, by ensuring that there are no stacked first microsphere particles 600 in the thickness direction of the first adhesive layer 200, it can be ensured that the number of layers of first microsphere particles 600 in the first adhesive layer 200 is only one, thus avoiding the problem that the overall display effect of the folding screen device would be greatly reduced due to the presence of more than two layers of first microsphere particles 600.

[0035] Optionally, the first microsphere particles 600 are connected to the first adhesive layer 200 by chemical bonds.

[0036] In this embodiment, voids are created when the microspheres separate from the OCA adhesive layer, altering the refractive index and scattering of light, thus affecting the display performance of the foldable screen. Therefore, in this embodiment, the first microspheres 600 are chemically bonded to the first adhesive layer 200, forming a strong and effective bond that integrates them seamlessly. This prevents the microspheres from separating from the adhesive layer due to weak adhesion during the folding process, thereby extending the lifespan of the foldable screen.

[0037] Optionally, the polarity of the material on the surface of the first microsphere 600 is the same as the polarity of the material of the first adhesive layer 200; and / or,

[0038] The surface of the first microsphere 600 has a first chemical functional group 630 formed by chemical grafting, and the first chemical functional group 630 is connected to the first adhesive layer 200 by chemical bonds.

[0039] The polarity of the aforementioned materials can include polar, non-polar, and weakly polar types. Correspondingly, "the polarity of the material on the surface of the first microsphere 600 is the same as the polarity of the material of the first adhesive layer 200" means that the type of polarity of the material on the surface of the first microsphere 600 is the same as the type of polarity of the material of the first adhesive layer 200. For example, both the polarity of the material on the surface of the first microsphere 600 and the polarity of the material of the first adhesive layer 200 are polar. Or, both the polarity of the material on the surface of the first microsphere 600 and the polarity of the material of the first adhesive layer 200 are non-polar, etc.

[0040] Specifically, the material of the surface of the first microsphere 600 can refer to the material of the outer shell of the first microsphere 600. The outer shell of the first microsphere 600 and the first adhesive layer 200 can be made of various materials with the same polarity. The materials of the outer shell of the first microsphere 600 and the first adhesive layer 200 can be the same or different, as long as their polarities are the same. For example, in some embodiments of this application, the outer shell of the first microsphere 600 and the first adhesive layer 200 can both be made of the same acrylic resin.

[0041] Specifically, based on the principle of "like dissolves like," first microspheres 600 of the same polarity are filled into the first adhesive layer 200. The surface of the first microspheres 600 forms an effective and strong adhesion with the first adhesive layer 200, making the first microspheres 600 and the first adhesive layer 200 integrated. The principle of "like dissolves like" primarily involves wetting by substances of the same polarity, not dissolution in the traditional sense. That is, the outer shell of the first microspheres 600 will not dissolve into the first adhesive layer 200, and the outer shell of the first microspheres 600 in the first adhesive layer 200 will not dissipate. The strong adhesion refers to the formation of chemical bonds between the outer shell of the first microspheres 600 and the first adhesive layer 200, thus enabling the first microspheres 600 to be connected to the first adhesive layer 200 through chemical bonds.

[0042] In other embodiments of this application, the polarity of the material on the surface of the first microsphere 600 is different from the polarity of the material on the first adhesive layer 200, and the surface of the first microsphere 600 has a first chemical functional group 630 formed by chemical grafting treatment, and the first chemical functional group 630 is connected to the first adhesive layer 200 by chemical bonds.

[0043] In other embodiments of this application, the polarity of the material on the surface of the first microsphere 600 is the same as the polarity of the material of the first adhesive layer 200, and the surface of the first microsphere 600 has a first chemical functional group 630 formed by chemical grafting treatment, and the first chemical functional group 630 is connected to the first adhesive layer 200 by chemical bonds.

[0044] It should be noted that when the polarity of the material on the surface of the first microsphere 600 is different from the polarity of the material on the first adhesive layer 200, the polarity of the material on the surface of the first microsphere 600 can be made similar to the polarity of the material on the first adhesive layer 200. Since two materials with similar polarities may also form chemical bonds, this is beneficial to improving the strong adhesion between the first microsphere 600 and the first adhesive layer 200. Here, "similar polarity" can mean that one of the polarities of the material on the surface of the first microsphere 600 and the material on the first adhesive layer 200 is polar, and the other is weakly polar.

[0045] In some embodiments of this application, the first adhesive layer 200 may be made of acrylic resin to improve the overall light performance of the first adhesive layer 200. The outer shell of the first microsphere 600 may be made of polymethyl methacrylate (PMMA), and the core of the first microsphere 600 may be made of rigid silica, polystyrene (PS), or rigid PMMA, etc.

[0046] The aforementioned first chemical functional group 630 can be any type of functional group capable of forming chemical bonds with the first adhesive layer 200. For example, the first chemical functional group 630 can be tetrabutyl titanate, siloxane, or other chemical functional groups. Specifically, a chemical grafting treatment can be performed on the surface of the first microsphere particles 600, thereby enabling the first microsphere particles 600 to be connected to the first adhesive layer 200 through chemical bonds. Please refer to Figure 5, which is a schematic diagram of the strong adhesion between the first microsphere particles 600 and the first adhesive layer 200 through the first chemical functional group 630 on the surface.

[0047] In this embodiment, by making the polarity of the material on the surface of the first microsphere 600 the same as the polarity of the material of the first adhesive layer 200; and / or, the surface of the first microsphere 600 has a first chemical functional group 630 formed by chemical grafting treatment, and the first chemical functional group 630 is connected to the first adhesive layer 200 by chemical bonds, the first microsphere 600 can be connected to the first adhesive layer 200 by chemical bonds.

[0048] Optionally, the first microsphere particle 600 includes a first core 610 and a first shell 620, the first core 610 and the first shell 620 are connected by chemical bonds, and the elastic modulus of the first shell 620 is in the range of 1 to 1.1 times the elastic modulus of the first adhesive layer 200.

[0049] It is understood that the connection between the first microsphere particle 600 and the first adhesive layer 200 via chemical bonds can mean that the first shell 620 of the first microsphere particle 600 is connected to the first adhesive layer 200 via chemical bonds.

[0050] The elastic modulus mentioned above is a physical quantity that describes a material's ability to resist deformation during the elastic deformation stage, and is usually defined as the ratio of stress to strain.

[0051] In some embodiments of this application, the elastic modulus of the first housing 620 can be adjusted to be 1 to 1.1 times that of the elastic modulus of the first adhesive layer 200 by adjusting the formulation of the first housing 620.

[0052] In this embodiment, by setting the elastic modulus of the first outer shell 620 to be 1 to 1.1 times that of the elastic modulus of the first adhesive layer 200, the first microsphere particles 600 can undergo reversible elastic deformation during the folding process of the foldable screen device, thereby absorbing bending stress and preventing creep accumulation of the first adhesive layer 200, thus slowing down the formation of creases.

[0053] Optionally, in the first adhesive layer 200, the distance between two adjacent first microsphere particles 600 is between 50 μm and 100 μm.

[0054] Specifically, the distance between two adjacent first microsphere particles 600 is between 50um and 100um, which means that the density of the first microsphere particles 600 in the first adhesive layer 200 is 1-2 first microsphere particles 600 per 100um length section.

[0055] In this embodiment, by setting the distance between two adjacent first microsphere particles 600 in the first adhesive layer 200 to be between 50µm and 100µm, a certain spacing can be maintained between the first microsphere particles 600 in the first adhesive layer 200, thus preventing the first microsphere particles 600 from being too concentrated and affecting the display effect of the foldable screen device.

[0056] Optionally, the first microsphere particle 600 includes a first core 610 and a first shell 620, the first core 610 and the first shell 620 are connected by chemical bonds, and the refractive index of the first core 610, the refractive index of the first shell 620 and the refractive index of the first adhesive layer 200 are equal.

[0057] The refractive index of the first outer shell 620 can be adjusted by selecting acrylic resins with different formulations. The refractive index of the first core 610 can be adjusted by grain size and surface morphology. For example, when the first core 610 is made of SiO2, its refractive index can be adjusted by grain size and surface morphology. When the first core 610 is made of PS, its refractive index can be adjusted by molecular chain length and degree of polymerization. It should be noted that microspheres with different refractive indices are readily available for purchase in related technologies.

[0058] Please refer to Figure 6(b). When the refractive indices of the first core 610, the first outer shell 620, and the first adhesive layer 200 are equal, the optical path in the first adhesive layer 200 can be controlled. Please refer to Figure 6(a). When the number of microspheres in the first adhesive layer 200 is not limited, and the refractive indices of the microspheres and the first adhesive layer 200 are not limited, the optical path in the first adhesive layer 200 will be uncontrollable.

[0059] In this embodiment, by making the refractive index of the first core 610, the refractive index of the first outer shell 620, and the refractive index of the first adhesive layer 200 equal, the optical path in the first adhesive layer 200 can be controlled, thereby improving the display effect of the foldable screen device.

[0060] Optionally, the second adhesive layer 400 is provided with a plurality of second microspheres 700, and the plurality of second microspheres 700 are distributed in multiple layers in at least a portion of the second adhesive layer 400.

[0061] The aforementioned second microsphere 700 can also be a core-shell structure formed by micron-sized particles connected by chemical bonds to a heterogeneous outer shell.

[0062] The above-mentioned plurality of second microsphere particles 700 being distributed in at least a portion of the second adhesive layer 400 in a multilayer manner can mean that there are stacked second microsphere particles 700 in the thickness direction of the second adhesive layer 400, that is, there can be two or more layers of second microsphere particles 700 in the thickness direction of the second adhesive layer 400. The second microsphere particles 700 in different regions of the second adhesive layer 400 can be different. For example, please refer to Figure 7, which is a schematic diagram of the distribution of second microsphere particles 700 in the second adhesive layer 400 in some embodiments of this application.

[0063] In this embodiment, multiple second microspheres 700 are disposed within the second adhesive layer 400. During the folding process of the foldable screen device, the microsphere structure is not easily deformed and can form a thickness support effect, thereby preventing the second adhesive layer 400 from fatigue-induced thinning. When the foldable screen device unfolds, the microsphere structure has a certain degree of resilience, which can assist the adhesive layer in elastic deformation, thereby effectively reducing the formation of creases. At the same time, the microsphere structure can improve the overall rigidity of the screen. Furthermore, since the second adhesive layer 400 is located on the non-display side of the foldable screen device, by having the second microspheres 700 stacked in the thickness direction of the second adhesive layer 400, that is, having two or more layers of second microspheres 700 in the second adhesive layer 400, it is beneficial to improve the overall support and cushioning effect of the foldable screen, thereby further reducing the formation of creases.

[0064] Optionally, the second microsphere particles 700 are connected to the second adhesive layer 400 by chemical bonds.

[0065] In this embodiment, voids are created when the microspheres separate from the OCA adhesive layer, altering the refractive index and scattering of light, thus affecting the display performance of the foldable screen. Therefore, in this embodiment, the second microspheres 700 are chemically bonded to the second adhesive layer 400, forming a strong and effective bond that integrates them seamlessly. This prevents the microspheres from separating from the adhesive layer due to weak adhesion during the folding process, thereby extending the display lifespan of the foldable screen.

[0066] Optionally, the polarity of the material on the surface of the second microsphere 700 is the same as the polarity of the material of the second adhesive layer 400; and / or,

[0067] The surface of the second microsphere 700 has a second chemical functional group formed by chemical grafting treatment, and the second chemical functional group is connected to the second adhesive layer 400 by chemical bonds.

[0068] The statement that the polarity of the material on the surface of the second microsphere 700 is the same as the polarity of the material of the second adhesive layer 400 means that the type of polarity of the material on the surface of the second microsphere 700 is the same as the type of polarity of the material of the second adhesive layer 400. For example, both the type of polarity of the material on the surface of the second microsphere 700 and the type of polarity of the material of the second adhesive layer 400 are polar. Alternatively, both the type of polarity of the material on the surface of the second microsphere 700 and the type of polarity of the material of the second adhesive layer 400 are non-polar, etc.

[0069] Specifically, the material of the surface of the second microsphere 700 can refer to the material of the outer shell of the second microsphere 700. The outer shell of the second microsphere 700 and the second adhesive layer 400 can be made of various materials with the same polarity. The materials of the outer shell of the second microsphere 700 and the second adhesive layer 400 can be the same or different, as long as their polarities are the same. For example, in some embodiments of this application, the outer shell of the second microsphere 700 and the second adhesive layer 400 can both be made of the same acrylic resin.

[0070] Specifically, based on the principle of "like dissolves like," second microspheres 700 of the same polarity are filled into the second adhesive layer 400. The surface of the second microspheres 700 forms an effective and strong bond with the second adhesive layer 400, causing the second microspheres 700 and the second adhesive layer 400 to fuse together. The principle of "like dissolves like" primarily involves wetting by substances of the same polarity, not dissolution in the traditional sense. That is, the outer shell of the second microspheres 700 will not dissolve into the second adhesive layer 400, and the outer shell of the second microspheres 700 in the second adhesive layer 400 will not dissipate. The strong bond refers to the formation of chemical bonds between the outer shell of the second microspheres 700 and the second adhesive layer 400, thus enabling the second microspheres 700 to be connected to the second adhesive layer 400 through chemical bonds.

[0071] In other embodiments of this application, the polarity of the material on the surface of the second microsphere 700 is different from the polarity of the material on the second adhesive layer 400, and the surface of the second microsphere 700 has a second chemical functional group formed by chemical grafting treatment, and the second chemical functional group is connected to the second adhesive layer 400 by chemical bonds.

[0072] In other embodiments of this application, the polarity of the material on the surface of the second microsphere 700 is the same as the polarity of the material of the second adhesive layer 400, and the surface of the second microsphere 700 has a second chemical functional group formed by chemical grafting treatment, and the second chemical functional group is connected to the second adhesive layer 400 by chemical bonds.

[0073] It should be noted that when the polarity of the material on the surface of the second microsphere 700 is different from the polarity of the material on the second adhesive layer 400, the polarity of the material on the surface of the second microsphere 700 can be made similar to the polarity of the material on the second adhesive layer 400. Since two materials with similar polarities may also form chemical bonds, this is beneficial to improving the strong adhesion between the second microsphere 700 and the second adhesive layer 400. Here, "similar polarity" can mean that one of the polarities of the material on the surface of the second microsphere 700 and the material on the second adhesive layer 400 is polar, and the other is weakly polar.

[0074] In some embodiments of this application, the second adhesive layer 400 may be made of acrylic resin to improve the overall light performance of the second adhesive layer 400. The outer shell of the second microsphere 700 may be made of polymethyl methacrylate (PMMA), and the core of the second microsphere 700 may be made of rigid silica, polystyrene (PS), or rigid PMMA, etc.

[0075] The aforementioned second chemical functional group can be any type of functional group capable of forming chemical bonds with the second adhesive layer 400. For example, the second chemical functional group can be tetrabutyl titanate, siloxane, or other chemical functional groups. Specifically, a chemical grafting treatment can be performed on the surface of the second microsphere particles 700, thereby enabling the second microsphere particles 700 to be connected to the second adhesive layer 400 through chemical bonds.

[0076] In this embodiment, by making the polarity of the material on the surface of the second microsphere 700 the same as the polarity of the material of the second adhesive layer 400; and / or, by having the surface of the second microsphere 700 having a second chemical functional group formed by chemical grafting treatment, and the second chemical functional group being connected to the second adhesive layer 400 by chemical bonds, the second microsphere 700 can be connected to the second adhesive layer 400 by chemical bonds.

[0077] Optionally, the second microsphere 700 includes a second core 710 and a second shell 720, the second core 710 and the second shell 720 are connected by chemical bonds, and the elastic modulus of the second shell 720 is in the range of 1 to 1.1 times the elastic modulus of the second adhesive layer 400.

[0078] In some embodiments of this application, the elastic modulus of the second housing 720 can be adjusted to be 1 to 1.1 times that of the elastic modulus of the second adhesive layer 400 by adjusting the formulation of the second housing 720.

[0079] In this embodiment, by setting the elastic modulus of the second outer shell 720 to be 1 to 1.1 times that of the elastic modulus of the second adhesive layer 400, the second microsphere particles 700 can undergo reversible elastic deformation during the folding process of the foldable screen device, thereby absorbing bending stress and preventing creep accumulation of the second adhesive layer 400, thus slowing down the formation of creases.

[0080] Optionally, the particle size of the first microsphere 600 is 1 / 2 to 2 / 3 times the thickness of the first adhesive layer 200; the particle size of the second microsphere 700 is 1 / 5 to 2 / 5 times the thickness of the second adhesive layer 400.

[0081] Understandably, both the first microsphere 600 and the second microsphere 700 are micrometer-sized spheres.

[0082] The fabrication of the first adhesive layer 200 typically includes the following steps: adding first microsphere particles 600 to OCA liquid adhesive; coating the OCA liquid adhesive containing the first microsphere particles 600 onto a release film; rolling the liquid adhesive on the release film to a specified thickness; drying; ultraviolet (UV) curing; rolling; and cutting into sheets to obtain the first adhesive layer 200. By making the particle size of the first microsphere particles 600 1 / 2 to 2 / 3 times the thickness of the first adhesive layer 200, since the sum of the particle sizes of two first microsphere particles 600 will be greater than or equal to the thickness of the first adhesive layer 200, the thickness of two overlapping first microsphere particles 600 exceeding a predetermined limit during rolling will be squeezed to the other side during the pressure rolling process, thus ensuring that the first microsphere particles 600 in the first adhesive layer 200 are distributed in a single layer. At the same time, an appropriate amount of dispersant can be added to the formula to make the first microsphere particles 600 in the first adhesive layer 200 dispersed from each other and not overlap.

[0083] It should be noted that, since both the first adhesive layer 200 and the second adhesive layer 400 need to undergo UV curing during the manufacturing process, in order to avoid the first outer shell 620 of the first adhesive layer 200 and the second outer shell 720 of the second adhesive layer 400 dissolving in the corresponding adhesive layer during the UV curing process, resulting in the disappearance of the outer shell, in some embodiments of this application, the materials of the first outer shell 620 and the second outer shell 720 can be selected as materials that do not dissolve in OCA adhesive. For example, the materials of the first outer shell 620 and the second outer shell 720 can both be acrylic resin.

[0084] In this embodiment, by making the particle size of the first microsphere 600 1 / 2 to 2 / 3 times the thickness of the first adhesive layer 200, since the sum of the particle sizes of two first microspheres 600 will be greater than or equal to the thickness of the first adhesive layer 200, the stacking of the first microspheres 600 in the thickness direction of the first adhesive layer 200 can be avoided, ensuring that the first microspheres 600 in the first adhesive layer 200 are distributed in a single layer. Simultaneously, by making the particle size of the second microsphere 700 1 / 5 to 2 / 5 times the thickness of the second adhesive layer 400, the maximum number of stacked layers of the second microspheres 700 in the second adhesive layer 400 can be effectively controlled to not exceed 5 layers. This allows for control over the number of layers of the second microspheres 700 in the adhesive layer, thereby improving the support effect of the second adhesive layer 400.

[0085] Optionally, in the second adhesive layer 400, the sum of the volumes of the plurality of second microsphere particles 700 is 0.01 to 0.05 times the volume of the second adhesive layer 400.

[0086] In some embodiments of this application, during the fabrication of the first adhesive layer 200, the amount of the second microsphere particles 700 added is designed to be 1%-5% of the OCA adhesive volume.

[0087] In this embodiment, by making the sum of the volumes of the plurality of second microsphere particles 700 in the second adhesive layer 400 0.01 to 0.05 times the volume of the second adhesive layer 400, the second adhesive layer 400 can have both good support and good adhesion.

[0088] The foldable screen device provided in this application embodiment has at least the following beneficial effects:

[0089] This application's embodiments start from the design of the OCA adhesive layer of the crease itself, improving the creep resistance and rigidity of OCA, which can greatly improve the reliability of ball drop and pen drop tests and optimize the crease, preventing the crease from deepening.

[0090] With the development of foldable screen technology, the OCA in foldable screen devices will be further thinned. In related technologies, the effect of designing the outer structure of the foldable screen to reduce creases is becoming increasingly limited. However, in the embodiments of this application, the scheme of adding microsphere particle structure to the adhesive layer can maintain or improve the crease problem of the foldable screen device.

[0091] The embodiments of this application, through the layout design of different layers of OCA, can maintain the display effect to the greatest extent without thickening the OCA, and improve reliability and appearance crease effect.

[0092] It should be noted that the folding screen device provided in this application embodiment is not limited to the case of only including one first adhesive layer 200 and one second adhesive layer 400. Specifically, the number of adhesive layers can be set according to structural differences. For example, two or more first adhesive layers 200 can be provided between the flexible cover plate 100 and the display layer 300, and two or more second adhesive layers 400 can be provided between the display layer 300 and the support layer 500.

[0093] This application also provides an electronic device, which includes the foldable screen device described in the above embodiments.

[0094] The electronic device can be various types of foldable screen devices, such as foldable screen phones, foldable screen tablets, etc.

[0095] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A foldable screen apparatus comprising: A flexible cover plate, a first adhesive layer, a display layer, a second adhesive layer, and a support layer are stacked in sequence. The first adhesive layer contains a plurality of first microspheres, which are distributed in a single layer within the first adhesive layer. The first microsphere includes a first core and a first shell. When the first microsphere is subjected to an external force, the elastic deformation of the first shell is greater than that of the first core.

2. The folding screen device according to claim 1, wherein The polarity of the material on the surface of the first microsphere particles is the same as the polarity of the material of the first adhesive layer; and / or, The surface of the first microsphere has a first chemical functional group formed by chemical grafting, and the first chemical functional group is connected to the first adhesive layer by chemical bonds.

3. The folding screen device of claim 1, wherein, The elastic modulus of the first outer shell ranges from 1 to 1.1 times the elastic modulus of the first adhesive layer.

4. The folding screen device of claim 1, wherein, In the first adhesive layer, the distance between two adjacent first microsphere particles ranges from 50 μm to 100 μm.

5. The folding screen device of claim 1, wherein, The refractive index of the first core, the refractive index of the first outer shell, and the refractive index of the first adhesive layer are equal.

6. The folding screen device of claim 1, wherein, The second adhesive layer contains a plurality of second microspheres, which are distributed in multiple layers in at least a portion of the second adhesive layer.

7. The folding screen device according to claim 6, wherein The particle size of the first microsphere is 1 / 2 to 2 / 3 times the thickness of the first adhesive layer; the particle size of the second microsphere is 1 / 5 to 2 / 5 times the thickness of the second adhesive layer.

8. The folding screen device of claim 6, wherein, In the second adhesive layer, the sum of the volumes of the plurality of second microspheres is 0.01 to 0.05 times the volume of the second adhesive layer.

9. The folding screen device of claim 6, wherein, The polarity of the material on the surface of the second microsphere particles is the same as the polarity of the material of the second adhesive layer; and / or, The surface of the second microsphere has a second chemical functional group formed by chemical grafting, and the second chemical functional group is connected to the second adhesive layer by chemical bonds.

10. An electronic device comprising the folding screen device according to any one of claims 1 to 9.

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