Middle frame and manufacturing method thereof and electronic device

Abstract

An embodiment of the present application provides a middle frame, a manufacturing method thereof, and an electronic device, wherein the middle frame includes a first frame and a second frame, and the second frame is arranged on the outer periphery of the first frame, and the side of the second frame facing away from the first frame is an anodized surface, and the side of the second frame facing away from the first frame is the appearance surface of the middle frame, so that the appearance surface of the middle frame has an anodized effect, and because the first frame and the second frame are relatively independent, the performances of the first frame and the second frame do not affect each other. Therefore, the first frame has a high yield strength and the outer surface of the second frame has a high anodized effect, so that the middle frame can have a high anodized effect and a high yield strength, which solves the problem that the existing middle frame has poor yield strength while ensuring a high anode effect.

Description

Technical Field

[0001] The present application relates to the field of terminal technology, and in particular to a middle frame and a manufacturing method thereof and an electronic device. Background Art

[0002] The current development trend of terminal electronic devices (such as mobile phones, tablets, PCs, etc.) is to have multiple camera modules, multiple sensors, large batteries, and thinness. The space left for electronic device structural parts (such as the middle frame) is greatly reduced, but the requirements for the resistance to drops of the whole machine are constantly increasing. Therefore, the demand for the mechanical properties of the middle frame material (mainly yield strength) is constantly increasing. In addition, as people continue to pursue the beauty of electronic devices, middle frames with mirror anode effects are increasingly favored by consumers.

[0003] At present, the middle frame of electronic equipment is usually made of an aluminum alloy material through a CNC lathe (Computer numerical control, CNC) to form a metal frame, and then sandblasting, anodizing and other molding. The main way to improve the strength of the middle frame is to increase the alloying degree of the material. For example, for the mainstream 6 series aluminum alloy, the main thing is to increase the alloy content of silicon and copper in the alloy. However, the mirror anodizing effect has strict restrictions on the alloy composition of aluminum alloy materials, such as low magnesium, low silicon, low copper, etc., that is, the improvement of strength requires high alloying of the material, while the anodizing effect requires low alloying of the material, and the two are contradictory. In the related art, in order to ensure the mirror anode effect, the main way to improve the yield strength of the material is to optimize the alloy composition and the extrusion process. Among them, the alloy composition optimization is mainly to strictly control the alloy composition of magnesium, silicon and copper in the material, and the extrusion process optimization is mainly to control the extrusion speed and outlet temperature.

[0004] However, since improving the strength and enhancing the anode effect of the same alloy material are contradictory, in the above-mentioned optimization method, meeting the requirements of the anode effect of the middle frame will limit the yield strength of the material. The strength of the middle frame still needs to be further improved to meet the requirements for the drop resistance of electronic equipment. Summary of the invention

[0005] The present application provides a middle frame and a manufacturing method thereof and an electronic device, which solves the problem that the yield strength of the material of the existing middle frame needs to be further improved while ensuring a high anode effect.

[0006] The first aspect of the embodiment of the present application provides a middle frame, including a first frame and a second frame, the second frame is arranged on the periphery of the first frame, and the side of the second frame facing away from the first frame is an anodized surface. The middle frame includes the first frame and the second frame, the second frame is arranged on the periphery of the first frame, the side of the second frame facing away from the first frame is an anodized surface, and the side of the second frame facing away from the first frame is the appearance surface of the middle frame, so that the appearance surface of the middle frame has an anodized effect, and because the first frame and the second frame are relatively independent, the performance of the first frame and the second frame does not affect each other, therefore, the first frame has a high yield strength, and the outer surface of the second frame has a high anodized effect, so that the middle frame can have a high anodized effect and a high yield strength, which solves the problem that the existing middle frame has a poor yield strength under the premise of ensuring a high anode effect.

[0007] In a possible implementation, it further includes: a nano-connection layer, the nano-connection layer is located between the first frame and the second frame, and the nano-connection layer is used to make the second frame fit on the first frame. The nano-connection layer can realize the connection between the first frame and the second frame at low temperature, has a high connection strength, and can reduce the damage to the first frame and the second frame during the connection process. The nano-connection layer has strong anti-aging properties, ensuring the durability and aesthetics of the middle frame.

[0008] In a possible implementation, the first frame has a first coating on one side facing the second frame, the second frame has a second coating on one side facing the first frame, the first coating has a first nanowire, the second coating has a second nanowire, and the first nanowire and the second nanowire are connected to form the nano-connection layer. In this way, nano-connection between the first frame and the second frame is achieved by connecting the first nanowire of the first frame with the second nanowire of the second frame, so that the second frame is laminated on the periphery of the first frame.

[0009] In a possible implementation, the nano-connection layer includes an intermediate layer, the intermediate layer has a first nanowire on one side facing the first frame, the intermediate layer has a second nanowire on one side facing the second frame, the first frame has a first plating layer on one side facing the intermediate layer, the second frame has a second plating layer on one side facing the intermediate layer, the first plating layer is connected to the first nanowire, and the second plating layer is connected to the second nanowire. In this way, the nano-connection between the first frame and the second frame is achieved by growing the intermediate layer with the first nanowire and the second nanowire, and the second frame is laminated on the periphery of the first frame.

[0010] In a possible implementation, a first structural adhesive layer is further included, and the first structural adhesive layer covers the area where the first nanowire and the second nanowire are connected. By covering the first adhesive layer on the area where the first nanowire and the second nanowire are connected, the connection strength of the first nanowire and the second nanowire can be guaranteed, which helps to improve the drop resistance of the middle frame, especially when the connection temperature of the first nanowire and the second nanowire is room temperature, the first structural adhesive layer can effectively enhance the connection strength of the nano connection layer.

[0011] In a possible implementation, a second structural adhesive layer is further included, and the second structural adhesive layer covers the area where the first coating layer and the first nanowire are connected and the area where the second coating layer and the second nanowire are connected. The second structural adhesive layer ensures the connection strength between the first frame and the second frame and the intermediate layer, thereby enhancing the connection strength between the first frame and the second frame, especially when the connection temperature is room temperature, the second structural adhesive layer can effectively enhance the connection strength of the nano connection layer.

[0012] In a possible implementation, the thickness of the intermediate layer is 10-100 μm. A smaller thickness of the intermediate layer helps to reduce the thickness of the middle frame and improve the aesthetics of the middle frame.

[0013] In a possible implementation, the thickness of the first coating layer is 2-10 μm, the diameter of the first nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

[0014] In a possible implementation, the thickness of the second coating layer is 2-10 μm, the diameter of the second nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

[0015] In a possible implementation, the molding materials of the first frame and the second frame include aluminum alloy, stainless steel, titanium alloy, magnesium alloy, metal matrix composite material, glass, or ceramic, and the second frame is aluminum alloy.

[0016] In a possible implementation manner, the material of the nano-connection layer includes copper, gold, nickel, silver, platinum or tin.

[0017] In a possible implementation, the yield strength of the middle frame is greater than or equal to 450 MPa. The yield strength of the existing middle frame obtained by optimizing the alloy composition and the forming process can reach 380 MPa. Therefore, the middle frame of the embodiment of the present application effectively improves the strength of the middle frame while satisfying the high anode effect of the appearance.

[0018] In a possible implementation, the middle frame further includes: a middle plate, the first frame is arranged around an outer edge of the middle plate, and the middle plate is connected to an inner wall of the first frame.

[0019] A second aspect of an embodiment of the present application provides a method for manufacturing a middle frame, which is used to manufacture any of the above-mentioned middle frames, and the manufacturing method includes:

[0020] Arranging a second frame around the periphery of the first frame;

[0021] Anodizing is performed on a surface of the second frame that is away from the first frame, so that the surface of the second frame that is away from the first frame is an anodized surface.

[0022] In this way, the side of the second frame facing away from the first frame is the appearance surface of the middle frame, and the appearance surface is anodized to give it an anodized effect. The middle frame includes a relatively independent first frame and a second frame, and the strength of the first frame and the anodizing effect of the second frame can be improved respectively, and the two do not affect each other. In this way, the first frame has a high yield strength and the second frame has a high anodizing effect. Compared with the existing method of optimizing the alloy composition and the forming process, the method for manufacturing the middle frame provided in the embodiment of the present application can enable the middle frame to have a high yield strength while having a high anode effect.

[0023] In a possible implementation, the second frame is arranged on the periphery of the first frame, including:

[0024] The second frame is bonded to the outer periphery of the first frame by nano-connection.

[0025] Nano-connection can achieve low-temperature connection between different materials, and nano-connection has medium connection strength. Compared with welding or bonding, the second frame is bonded to the outer periphery of the first frame through nano-connection, which can reduce the damage to the first frame and the second frame during the bonding process. At the same time, it can also ensure that the first frame and the second frame have a high connection strength. The connected middle frame also has strong anti-aging properties.

[0026] In a possible implementation, the second frame is attached to the outer periphery of the first frame by nano-connection, including:

[0027] forming a first plating layer on a side of the first frame facing the second frame by electroplating;

[0028] forming a second plating layer on a side of the second frame facing the first frame by electroplating;

[0029] Growing a first nanowire on the surface of the first coating;

[0030] Growing a second nanowire on the surface of the second coating;

[0031] The second frame is arranged around the outer periphery of the first frame and is pressurized and connected.

[0032] Through the above process, the first nanowires on the second frame and the second nanowires on the second frame can be connected by pressurized connection, thereby realizing nano-connection between the first frame and the second frame, and setting the second frame on the periphery of the first frame.

[0033] In a possible implementation, the second frame is attached to the outer periphery of the first frame by nano-connection, including:

[0034] forming a first plating layer on a side of the first frame facing the second frame by electroplating;

[0035] forming a second plating layer on a side of the second frame facing the first frame by electroplating;

[0036] Growing a first nanowire and a second nanowire on two sides of the middle layer respectively;

[0037] The intermediate layer is placed between the first frame and the second frame, so that the second frame is arranged around the periphery of the first frame, and the first nanowire is close to the first frame, and the second nanowire is close to the second frame, and is connected by pressure. Through the above process, the first nanowire of the intermediate layer can be connected to the first plating layer on the first frame, and the second nanowire of the intermediate layer can be connected to the second plating layer on the second frame, so that the nano connection between the first frame and the second frame is realized through the intermediate layer, and the second frame is arranged on the periphery of the first frame.

[0038] In a possible implementation, the connection temperature of the pressurized connection is room temperature-250° C., the connection pressure is 15-50 MPa, and the connection time is 60 ms-60 s.

[0039] In a possible implementation manner, the thickness of the intermediate layer is 10-100 μm.

[0040] In a possible implementation, the thickness of the first coating layer is 2-10 μm, the diameter of the first nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

[0041] In a possible implementation, the thickness of the second coating layer is 2-10 μm, the diameter of the second nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

[0042] In a possible implementation, when the connection temperature is room temperature, after the pressurized connection, the method further includes:

[0043] A first structural adhesive layer is applied to the area where the first nanowire and the second nanowire are connected. When the connection temperature is room temperature, the connection strength between the first nanowire and the second nanowire is relatively weak due to the low temperature. The first structural adhesive layer is applied to the area where the first nanowire and the second nanowire are connected, so as to ensure the connection strength between the first nanowire and the second nanowire.

[0044] In a possible implementation, when the connection temperature is room temperature, after the pressurized connection, the method further includes: coating a second structural adhesive layer on the area where the first nanowire is connected to the first coating layer and the area where the second coating layer is connected to the second nanowire. Since the connection strength is weak due to the connection temperature being room temperature, coating the second structural adhesive layer on the area where the first nanowire is connected to the first coating layer and the area where the second coating layer is connected to the second nanowire can effectively ensure the connection strength between the first nanowire and the first coating layer, and between the second nanowire and the second coating layer.

[0045] In a possible implementation, the second frame is arranged around the periphery of the first frame, including: the second frame is sleeved on the first frame; or the second frame is arranged on the first frame along the periphery of the first frame. The second frame can be arranged around the periphery of the first frame by both of the above methods, and the nano-connection between the second frame and the first frame can be achieved by pressurized connection.

[0046] In a possible implementation, when at room temperature, the inner height of the second frame is less than the outer height of the first frame, and when the second frame is heated, the inner height of the second frame is greater than the outer height of the first frame, wherein the making the second frame sleeved on the first frame includes:

[0047] Heating the second frame and sleeve the second frame on the outer periphery of the first frame;

[0048] The pressurized connection includes: cooling the second frame to room temperature.

[0049] By utilizing the fact that the second frame expands at different temperatures and thus has different heights, the second frame is heated and placed on the outer periphery of the first frame. When cooled to room temperature, the height of the second frame is reduced, and the second frame is clamped on the outer periphery of the first frame, thereby enhancing the connection strength between the first frame and the second frame. At the same time, since the first frame and the second frame undergo elastic deformation after cooling, a self-pressurized connection can occur under the action of internal stress, so that the nano-connection between the first frame and the second frame can be achieved by cooling the second frame without pressurization.

[0050] In a possible implementation, after the pressurized connection, the method further includes:

[0051] Processing the pressurized composite middle frame through a CNC machine tool;

[0052] Cutting the antenna seam, and forming a nano-injection molded part by injection molding on the inner side of the first frame and in the antenna seam;

[0053] The outer surface of the second frame is ground and polished.

[0054] Through the above steps, the antenna seam is cut on the middle frame, a nano injection molded part for connection is formed on the middle frame, and the outer surface of the second frame is pre-treated for anodizing, thereby obtaining a molded middle frame.

[0055] In a possible implementation manner, after the anodizing treatment is performed on a side of the second frame facing away from the first frame, the method further includes:

[0056] Provide mid-board;

[0057] Connect the outer edge of the middle plate to the inner wall of the first frame.

[0058] A third aspect of the embodiments of the present application provides an electronic device, comprising: a display screen, a back cover, and any of the above-mentioned middle frames, wherein the middle frame is located between the display screen and the back cover. By providing the above-mentioned middle frame in the electronic device, the middle frame has a high anodizing effect and a high yield strength, which helps to improve the aesthetics of the electronic device and can ensure that the electronic device has a high drop resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A schematic diagram of the structure of an electronic device provided in one embodiment of the present application;

[0060] Figure 2 A schematic diagram of an exploded structure of an electronic device provided in one embodiment of the present application;

[0061] Figure 3 A schematic diagram of an exploded structure of a middle frame provided in an embodiment of the present application;

[0062] Figure 4 A front view of a middle frame provided in an embodiment of the present application;

[0063] Figure 5 A schematic diagram of the connection between the first frame and the second frame in the middle frame provided in an embodiment of the present application;

[0064] Figure 6 Another schematic diagram of the connection between the first frame and the second frame in the middle frame provided in an embodiment of the present application;

[0065] Figure 7 A cross-sectional microscopic schematic diagram of a middle frame provided in an embodiment of the present application;

[0066] Figure 8 A flowchart of a method for manufacturing a middle frame provided in an embodiment of the present application;

[0067] Fig. 9 A flow chart of a nano-connection method provided in one embodiment of the present application;

[0068] Fig.10 A schematic diagram of a middle frame manufacturing process provided in an embodiment of the present application;

[0069] Fig.11 Another schematic diagram of a middle frame manufacturing process provided by an embodiment of the present application;

[0070] Fig.12 Another flow chart of the nano-connection method provided in one embodiment of the present application.

[0071] Description of reference numerals:

[0072] 100-electronic device; 10-middle frame; 11-first frame; 111-first coating;

[0073] 112-first nanowire; 12-second frame; 121-second coating; 122-second nanowire;

[0074] 13-nano connection layer; 131-middle layer; 14-middle plate; 15-nano injection molded part;

[0075] 16-battery; 17-circuit board; 18-frame; 20-display screen;

[0076] 30-Back cover. DETAILED DESCRIPTION

[0077] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0078] In response to the development demand for thinner and lighter electronic devices, the molding materials of the middle frames of electronic devices are mostly metal alloy materials. Specifically, aluminum alloy materials are used to form the frame of the middle frame through CNC machine tools. With the continuous pursuit of consumers for the anti-drop ability of the middle frame and the aesthetics of the frame, the middle frame with high yield strength and high mirror anode effect has become a development trend. Among them, the main means to improve the strength of the middle frame is to increase the alloying degree of the middle frame molding material, but the mirror anode effect has strict restrictions on the alloy composition of the alloy material, that is, the required alloy composition is relatively low. Therefore, the enhancement of the strength of the same alloy material and the improvement of the anode effect are contradictory. In related technologies, the requirements of strength and anode effect are mostly met by further optimizing the alloy composition and molding process, but meeting the anode effect of the middle frame will inevitably affect the yield strength of the alloy material. There is a problem that the strength of the middle frame is poor under the premise of ensuring the high anode effect of the middle frame.

[0079] In order to make the middle frame have a high mirror anode effect and a high yield strength at the same time, an embodiment of the present application provides a middle frame, which includes a first frame and a second frame, and the second frame is arranged on the outer periphery of the first frame, and the side of the second frame facing away from the first frame is the appearance surface of the middle frame, so that the surface has an anodized effect, wherein the first frame and the second frame are relatively independent, and the performance of the two will not affect each other, so that the first frame can have a high yield strength, and the outer surface of the second frame can have a high anodized effect, so that the middle frame has a high yield strength while having a high anodized effect.

[0080] The embodiment of the present application sets the above-mentioned middle frame in the electronic device. The middle frame has a high anodizing effect and a high yield strength, which helps to improve the aesthetics of the electronic device and can ensure that the electronic device has a high drop resistance.

[0081] The electronic device provided in the embodiments of the present application may include but is not limited to a mobile or fixed terminal with a middle frame, such as a mobile phone, a tablet computer, a laptop computer, an ultra-mobile personal computer (UMPC), a handheld computer, a walkie-talkie, a netbook, a POS machine, a personal digital assistant (PDA), a wearable device, a virtual reality device, etc.

[0082] Among them, in the embodiments of the present application, a mobile phone is taken as an example of the above-mentioned electronic device for description. The mobile phone can be a foldable mobile phone, or a straight-screen mobile phone, or a sliding mobile phone. The following is a specific description taking a straight-screen mobile phone as an example.

[0083] Figure 1 A three-dimensional diagram of an electronic device. Figure 2For an exploded view of an electronic device, see Figure 1 and Figure 2 As shown, the electronic device 100 may include: a display screen 20 , a back cover 30 and a middle frame 10 , wherein the middle frame 10 is located between the display screen 20 and the back cover 30 .

[0084] See also Figure 2 As shown, the middle frame 10 may include a middle plate 14 and a frame 18 surrounding the outer edge of the middle plate 14, the inner wall of the frame 18 may be connected to the outer edge of the middle plate 14 to form an integral structure, and the material of the middle plate 14 may be aluminum or an aluminum alloy, or the material of the middle plate 14 may be stainless steel. Of course, in some other examples, the middle frame 10 may not include the middle plate 14, for example, the middle frame 10 only includes the frame 18.

[0085] The electronic device 100 may further include a battery 16 and a circuit board 17 , which may be disposed on the middle plate 14 , for example, the battery 16 and the circuit board 17 may be disposed on a side of the middle plate 14 facing the display screen 20 , or on a side of the middle plate 14 facing the back cover 30 .

[0086] The back cover 30 may be a metal back cover, a glass back cover, a plastic back cover, or a ceramic back cover.

[0087] The middle frame of the embodiment of the present application is described in detail below through two different embodiments.

[0088] Embodiment 1

[0089] The middle frame 10 provided in the embodiment of the present application may include a first frame 11 and a second frame 12, for example Figure 3 As shown, the frame 18 in the middle frame 10 may include a first frame 11 and a second frame 12, wherein the second frame 12 is arranged on the periphery of the first frame 11, and the side of the second frame 12 facing away from the first frame 11 is an anodized surface, and the side of the second frame 12 facing away from the first frame 11 (that is, the outer surface of the second frame 12) is the appearance surface of the middle frame 10, that is, the appearance surface of the middle frame 10 has an anodized effect, and since the middle frame 10 includes the first frame 11 and the second frame 12 arranged on the first frame 11, the first frame 11 and the second frame 12 are relatively independent, and the performance optimization of the first frame 11 and the second frame 12 will not affect each other, so the strength of the first frame 11 and the anodized effect of the second frame 12 can be improved respectively, so that the first frame 11 has a high yield strength, and the outer surface of the second frame 12 has a high anodized effect, so that the middle frame 10 can have a high anodized effect and a high yield strength at the same time, which solves the problem that the yield strength of the existing middle frame is poor under the premise of ensuring a high anode effect. In addition, it also helps to improve the yield rate of the anode manufacturing of the middle frame.

[0090] Among them, in the embodiment of the present application, the molding material of the first frame 11 can be an aluminum alloy material with high yield strength, and the molding material of the second frame 12 can be an aluminum alloy material with low strength or medium strength and high anode effect. Specifically, the strength of the first frame 11 can be enhanced by increasing the alloy composition in the aluminum alloy material of the first frame 11, and the anode effect of the second frame 12 can be improved by reasonably controlling the alloy composition in the aluminum alloy material of the second frame 12.

[0091] See also Figure 4 As shown, in the embodiment of the present application, the middle frame 10 may also include: a nano-injection molding part 15, the nano-injection molding part 15 is located on the inner side of the first frame 11, and the nano-injection molding part 15 is used to fill the antenna seam formed by cutting on the middle frame 10. In addition, the nano-injection molding part 15 also serves to connect the middle plate 14 of the electronic device 100 and the first frame 11. For example, the inner wall of the first frame 11 and the outer edge of the middle plate 14 are connected into a whole through plastic injection molding, and the middle plate 14 and the inner wall of the first frame 11 are connected through the nano-injection molding part 15.

[0092] The second frame 12 is fixedly arranged on the outer periphery of the first frame 11. It is understandable that the connection method between the first frame 11 and the second frame 12 should have a certain connection strength to ensure the overall strength of the middle frame 10. For example, the first frame 11 and the second frame 12 can be connected by welding or bonding. However, welding often requires a higher temperature, which may easily soften the alloy material of the first frame 11 and the second frame 12; and bonding has a problem of weak aging resistance, which affects the long-lasting aesthetics of the middle frame 10.

[0093] In the embodiment of the present application, the first frame 11 and the second frame 12 may be connected by nano-connection, for example Figure 5 As shown, the middle frame 10 may further include a nano-connection layer 13 , which is located between the first frame 11 and the second frame 12 . The nano-connection layer 13 is used to make the second frame 12 fit on the first frame 11 .

[0094] Among them, the nanowire connection layer is a connection layer formed by pressurizing and welding metal nanomaterials. The nano connection technology refers to the connection between metals through nanomaterials. Nanomaterials refer to materials that have at least one dimension in nanometer size (1-100nm) in three-dimensional space or are composed of them as basic units. Due to the small size of nanomaterials, the ratio of the number of atoms on the surface of nanomaterials to the total number of atoms increases sharply as the particle size decreases, that is, the number of atoms on the surface of nanomaterials is large, and the specific surface area is large. At the same time, nanomaterials have high activity and mobility, so that nanomaterials can be welded and connected under the action of low temperature. The connection temperature can be less than or equal to 250°C, and the lowest can be as low as room temperature. At the same time, the nano connection layer has a medium connection strength. Therefore, compared with the welding or bonding method, the second frame 12 is attached to the outer periphery of the first frame 11 through the nano connection layer 13, which can reduce the damage to the first frame 11 and the second frame 12 during the attachment and connection process, and the nano connection layer 13 has strong anti-aging properties, and can also ensure that the first frame 11 and the second frame 12 have a high connection strength.

[0095] In one possible implementation, see Figure 5 As shown, the first frame 11 has a first coating 111 on one side facing the second frame 12, and the second frame 12 has a second coating 121 on one side facing the first frame 11, wherein the first coating 111 has a first nanowire 112, and the second coating 121 has a second nanowire 122, the first nanowire 112 and the second nanowire 122 can be welded under low temperature and pressure, and the first nanowire 112 and the second nanowire 122 are connected to form a nano connection layer 13, so that the nano connection between the first frame 11 and the second frame 12 is achieved through the welding connection of the first nanowire 112 on the first frame 11 and the second nanowire 122 on the second frame 12, so that the second frame 12 is fitted on the outer periphery of the first frame 11.

[0096] The first nanowire and the second nanowire refer to a one-dimensional structure with a lateral size of less than 100 nm. Since the lateral size of the first nanowire and the second nanowire is small, when the first nanowire and the second nanowire are in contact at low temperature, the first nanowire and the second nanowire will first be entangled with each other to form a certain connection strength, and then the first nanowire and the second nanowire will be welded under the action of temperature and pressure to further strengthen the connection between the two. Therefore, compared with other common nanomaterials of other shapes, such as zero-dimensional nanoparticles, nanofilms, etc., the connection achieved through nanowires has better connection strength, which helps to improve the connection strength between the first frame 11 and the second frame 12.

[0097] Specifically, the first coating 111 and the second coating 121 can be formed on the surfaces of the first frame 11 and the second frame 12 respectively by electroplating, and then the first nanowires 112 are electro-deposited on the surface of the first coating 111 and the second nanowires 122 are electro-deposited on the surface of the second coating 121 by electrodeposition.

[0098] The metal of the first coating 111 and the second coating 121 may be the same metal or different metals, and the metal of the first nanowire 112 on the first coating 111 may be the same as or different from that of the first coating 111; accordingly, the metal of the second nanowire 122 on the second coating 121 may be the same as or different from that of the second coating 121. In the embodiment of the present application, the metal of the first nanowire 112 is the same as that of the first coating 111, and the metal of the second nanowire 122 is the same as that of the second coating 121, which can facilitate the growth of the first nanowire 112 and the second nanowire 122 on the first coating 111 and the second coating 121, respectively; at the same time, the metal of the first nanowire 112 and the second nanowire 122 is also the same, which can facilitate the connection between the first nanowire 112 and the second nanowire 122.

[0099] In a possible implementation, the middle frame 10 further includes a first structural adhesive layer (not shown), which covers the area where the first nanowire 112 and the second nanowire 122 are connected, further ensuring the connection strength of the first nanowire 112 and the second nanowire 122, thereby ensuring the connection strength between the first frame 11 and the second frame 12, which helps to improve the drop resistance of the middle frame 10. In addition, the connection temperature between the first nanowire 112 and the second nanowire 122 is less than or equal to 250°C. When the connection temperature of the first nanowire 112 and the second nanowire 122 is room temperature, the connection strength of the nano connection layer 13 formed after the connection is relatively weak, and the first structural adhesive layer can effectively enhance the connection strength of the nano connection layer 13. Among them, the first structural adhesive layer can be an adhesive layer formed by acrylic structural adhesive or the like.

[0100] The first coating layer 111 has a thickness of 2-10 μm, the first nanowire 112 has a diameter of 30 nm-2 μm, and a length of 0.5-50 μm. The second coating layer 121 has a thickness of 2-10 μm, the second nanowire 122 has a diameter of 30 nm-2 μm, and a length of 0.5-50 μm.

[0101] In the embodiment of the present application, the second frame 12 has the same shape as the first frame 11. For example, the second frame 12 may be an annular structure, so that the size of the second frame 12 is larger than the size of the first frame 11. The second frame 12 may be sleeved on the periphery of the first frame 11 and then pressurized and welded to connect. The inner wall of the second frame 12 and the outer wall of the first frame 11 may fit each other, or there may be a certain gap. The second frame 12 may be a closed annular shape, or the second frame 12 may be a non-closed annular shape, and the second frame 12 may have the same shape as the first frame 11.

[0102] Specifically, a first plating layer 111 is formed by electroplating on a surface of the first frame 11 facing the second frame 12, a first nanowire 112 is formed on the first plating layer 111, a second plating layer 121 is formed by electroplating on a surface of the second frame 12 facing the first frame 11, and a second nanowire 122 is formed on the second plating layer 121. The second frame 12 is sleeved on the outer periphery of the first frame 11, and pressure welding is performed to connect the first nanowire 112 and the second nanowire 122 to form a nano connection layer 13. In this way, the second frame 12 is fixed around the outer periphery of the first frame 11 to form a composite middle frame 10.

[0103] Alternatively, the second frame 12 may be a strip structure, with one end of the second frame 12 as the starting point, extending along the periphery of the first frame 11 and being fitted on the first frame 11. The other end of the second frame 12 may fit with one end of the starting point, or there may be a gap between the two.

[0104] Specifically, a first plating layer 111 is formed by electroplating on a surface of the first frame 11 facing the second frame 12, a first nanowire 112 is formed on the first plating layer 111, a second plating layer 121 is formed by electroplating on a surface of the second frame 12 facing the first frame 11, and a second nanowire 122 is formed on the second plating layer 121. Starting from one end of the second frame 12, the second frame 12 is sequentially attached to the first frame 11 along the outer periphery of the first frame 11, and pressure welding is performed at the same time to connect the first nanowire 112 and the second nanowire 122 to form a nano connection layer 13. In this way, the second frame 12 is fixed around the outer periphery of the first frame 11 to form a middle frame 10.

[0105] The material of the nano-connection layer 13 may include copper, gold, nickel, silver, platinum or tin, or other metals, so that nanowires can be easily grown on the metal substrate. At the same time, since the molding materials of the first frame 11 and the second frame 12 are mostly metals or their alloys, the metal nano-connection layer 13 can be easily connected to the frame and has a certain connectivity. Accordingly, the first nanowire 112 and the second nanowire 122 can be metal nanowires, and the first plating layer 111 and the second plating layer 121 can be metal plating layers.

[0106] The molding materials of the first frame 11 and the second frame 12 include aluminum alloy, stainless steel, titanium alloy, magnesium alloy, metal-based composite material, glass or ceramic, and the molding material of the second frame is an alloy. In a possible implementation, the molding materials of the first frame 11 and the second frame 12 are aluminum alloy, and the alloy composition of the second frame 12 is less than the alloy composition of the first frame 11. The first frame 11 has a higher yield strength, and the second frame 12 has a higher anodizing effect, so that the middle frame 10 has a high yield strength and a high mirror anode effect.

[0107] The composite middle frame 10 is formed by the first frame 11 and the second frame 12. The molding material of the first frame 11 is a high-strength alloy material. The yield strength of the composite middle frame 10 can reach 450MPa or more. The middle frame 10 obtained by optimizing the alloy composition and the molding process in the above-mentioned related technology can have a yield strength of 380MPa. Therefore, the middle frame 10 of the embodiment of the present application effectively improves the strength of the middle frame 10 while satisfying the high anode effect on the appearance.

[0108] In addition, at least one side of the middle frame 10 can be a curved surface. Specifically, the two ends of the upper and lower sides can be 2D curved surfaces or 3D curved surfaces, which enhances the aesthetics of the middle frame 10 and can be adapted to various designs of the middle frame 10. The middle frame 10 is composed of a first frame 11 and a second frame 12. Therefore, at least one side of the first frame 11 can be a curved surface, and the corresponding position of the second frame 12 can also be a curved surface, or only at least one side of the second frame 12 can be a curved surface.

[0109] Embodiment 2

[0110] In the examples of this application, see Figure 6 As shown, different from the first embodiment, the nano-connection layer 13 includes an intermediate layer 131, the intermediate layer 131 has a first nanowire 112 on a surface facing the first frame 11, and has a second nanowire 122 on a surface facing the second frame 12, a first plating layer 111 is provided on a surface of the first frame 11 facing the intermediate layer 131, and a second plating layer 121 is provided on a surface of the second frame 12 facing the intermediate layer 131, the first plating layer 111 and the first nanowire 112 are connected, that is, the first frame 11 is connected to the intermediate layer 131; the second plating layer 121 and the second nanowire 122 are connected, that is, the second frame 12 is connected to the intermediate layer 131, so that the nano-connection between the first frame 11 and the second frame 12 is achieved by growing the intermediate layer 131 with the first nanowire 112 and the second nanowire 122, so that the second frame 12 is fitted on the outer periphery of the first frame 11.

[0111] Among them, in embodiment one, the first nanowire 112 is grown on the first coating 111 of the first frame 11, and the second nanowire 122 is grown on the second coating 12 of the second frame 12. The first frame 11 and the second frame 12 both include an upper frame, a lower frame, a left frame and a right frame. Taking the first frame 11 as an example, when the first nanowire 112 is formed on the first coating 111 on the upper frame of the first frame 11, its lower frame, left frame and right frame need to be blocked. Then, when the first nanowire 112 is formed on the left frame, the upper frame, right frame and lower frame need to be blocked, and so on. At the same time, the side of the first frame 11 facing away from the second frame 12 needs to be blocked during the whole process. In this way, the steps required to form the first nanowire 112 and the second nanowire 122 on the first frame 11 and the second frame 12 respectively are more complicated and difficult.

[0112] In the embodiment of the present application, the first nanowire 112 and the second nanowire 122 are grown on the intermediate layer 131, and then the nano-connection between the first frame 11 and the second frame 12 is achieved through the intermediate layer 131. The steps required to form the first nanowire 112 and the second nanowire 122 on both sides of the intermediate layer 131 are relatively few and easy to implement, which greatly reduces the difficulty of the process.

[0113] Specifically, the middle layer 131 may be a metal middle layer. The first plated layer 111 and the second plated layer 121 may be formed on the surfaces of the first frame 11 and the second frame 12 by electroplating, and the first nanowires 112 and the second nanowires 122 may be electrodeposited on the two surfaces of the middle layer 131 by electroplating.

[0114] See also Figure 7 As shown, in the embodiment of the present application, the first nanowire 112 and the second nanowire 122 on the intermediate layer 131 are bent after pressurized welding, entangled with each other and welded with the first coating 111 of the first frame 11 and the second coating 121 of the second frame 12 respectively, so that the first frame 11 and the second frame 12 are connected through the nano-connection layer 13, and have a high connection strength.

[0115] In one possible implementation, the middle frame 10 further includes a second structural adhesive layer (not shown), which covers the area where the first coating layer 111 and the first nanowire 112 are connected, and the area where the second coating layer 121 and the second nanowire 122 are connected can also cover the second structural adhesive layer, thereby ensuring the connection strength between the first frame 11 and the second frame 12 and the intermediate layer 131, enhancing the connection strength between the first frame 11 and the second frame 12, and thus improving the anti-drop performance of the middle frame 10. In addition, the connection temperature when the first coating layer 111 and the first nanowire 112 and the second coating layer 121 and the second nanowire 122 are pressurized is less than or equal to 250°C. When the connection temperature is room temperature, the connection strength between the intermediate layer 131 and the first frame 11 is weak, and the connection strength between the intermediate layer 131 and the second frame 12 is also weak. The second structural adhesive layer can effectively enhance the connection strength between the intermediate layer 131 and the first frame 11 and the second frame 12. The second structural adhesive layer can be an adhesive layer formed by acrylic structural adhesive or the like.

[0116] The thickness of the middle layer 131 is 10-100 μm, and the thickness of the middle layer 131 is relatively small, which helps to reduce the thickness of the middle frame 10 and improve the aesthetics of the middle frame 10 .

[0117] In the embodiment of the present application, the second frame 12 and the first frame 11 have the same shape, such as the second frame 12 can be an annular structure, and the second frame 12 can be sleeved on the outer periphery of the first frame 11. Specifically, the first plating layer 111 is formed by electroplating on the side of the first frame 11 facing the second frame 12, and the second plating layer 121 is formed by electroplating on the side of the second frame 12 facing the first frame 11, and the first nanowire 112 and the second nanowire 122 are formed on both sides of the intermediate layer 131, and the intermediate layer 131 is placed between the first frame 11 and the second frame 12, and the second frame 12 is sleeved on the outer periphery of the first frame 11, and the first plating layer 111 of the first frame 11 is connected to the first nanowire 112, and the second plating layer 121 of the second frame 12 is connected to the second nanowire 122, so that the second frame 12 is fixed around the outer periphery of the first frame 11 to form the middle frame 10.

[0118] Alternatively, the second frame 12 may be a strip structure, with one end of the second frame 12 as the starting point, the second frame 12 is extended along the periphery of the first frame 11 and is bonded to the first frame 11. Specifically, the first plating layer 111 is formed by electroplating on the side of the first frame 11 facing the second frame 12, the second plating layer 121 is formed by electroplating on the side of the second frame 12 facing the first frame 11, and the first nanowires 112 and the second nanowires 122 are formed on both sides of the intermediate layer 131, the intermediate layer 131 is arranged around the periphery of the first frame 11, and with one end of the second frame 12 as the starting point, the second frame 12 is bonded to the intermediate layer 131 along the periphery of the first frame 11, that is, the intermediate layer 131, and pressure welding is performed at the same time to connect the first nanowires 112 and the first plating layer 111, and the second nanowires 122 and the second plating layer 121, so that the second frame 12 can be fixed around the periphery of the first frame 11 to form the middle frame 10.

[0119] The embodiment of the present application further provides a method for manufacturing a middle frame, which is used to manufacture any of the above-mentioned middle frames. The method for manufacturing the middle frame in the embodiment of the present application is described in detail below through two different scenarios.

[0120] Embodiment 3

[0121] See also Figure 8 As shown, the embodiment of the present application provides a method for manufacturing a middle frame, and takes the middle frame of a straight-screen mobile phone as an example for specific description, providing a first frame 11 and a second frame 12, and the method for manufacturing the middle frame 10 includes:

[0122] S801: setting a second frame around the outer periphery of the first frame;

[0123] S802: performing anodizing treatment on a side of the second frame facing away from the first frame, so that the side of the second frame facing away from the first frame is an anodized surface.

[0124] Among them, the second frame 12 is arranged around the outer periphery of the first frame 11, so that the side of the second frame 12 facing away from the first frame 11 is the appearance surface of the middle frame 10, and the appearance surface is anodized to make it have an anodization effect, and the middle frame 10 includes a relatively independent first frame 11 and a second frame 12, which can respectively improve the strength of the first frame 11 and the anodization effect of the second frame 12, and the two do not affect each other, so that the first frame 11 has a high yield strength, and the second frame 12 has a high anodization effect. Compared with the existing method of optimizing the alloy composition and the forming process, the method for manufacturing the middle frame 10 provided in the embodiment of the present application can make the middle frame 10 have a high yield strength while having a high anode effect, which solves the problem that the existing middle frame has poor yield strength while ensuring a high anode effect.

[0125] In the embodiment of the present application, the second frame 12 is disposed on the outer periphery of the first frame 11 , and a specific arrangement includes: the second frame 12 is adhered to the outer periphery of the first frame 11 by nano-connection.

[0126] Nano-connection can achieve low-temperature connection between different materials, and the connection temperature can be less than or equal to 250°C, and can be as low as room temperature. At the same time, nano-connection has medium connection strength. Therefore, compared with welding or bonding, the second frame 12 is bonded to the outer periphery of the first frame 11 by nano-connection. The damage to the first frame 11 and the second frame 12 during the bonding process can be reduced, and at the same time, a high connection strength between the first frame 11 and the second frame 12 can be ensured. The connected middle frame 10 also has strong anti-aging properties.

[0127] In a possible implementation, the second frame 12 is attached to the outer periphery of the first frame 11 by nano-connection, see Fig. 9 As shown, specifically including:

[0128] S901: forming a first plating layer on a side of the first frame facing the second frame by electroplating;

[0129] S902: forming a second plating layer on a side of the second frame facing the first frame by electroplating;

[0130] S903: growing a first nanowire on the surface of the first coating layer;

[0131] S904: growing a second nanowire on the surface of the second coating layer;

[0132] S905: The second frame is arranged around the outer periphery of the first frame and connected by pressurization.

[0133] Through the above process, the first nanowire 112 on the second frame 12 and the second nanowire 122 on the second frame 12 can be connected by pressurized connection, thereby realizing nano-connection between the first frame 11 and the second frame 12, and setting the second frame 12 on the periphery of the first frame 11.

[0134] The connection temperature of the pressurized connection is room temperature-250°C, the connection pressure is 15-50MPa, the connection time is 60ms-60s, the tensile strength of the weld is 20MPa, and the shear strength is 30MPa. In a possible implementation, the connection temperature is room temperature. After the pressurized connection in the above step S905, the method further includes: coating a first structural adhesive layer on the area where the first nanowire 112 and the second nanowire 122 are connected. Since the connection temperature when the first nanowire 112 and the second nanowire 122 are pressurized and connected is room temperature, the temperature is low and the connection strength of the first nanowire 112 and the second nanowire 122 is relatively weak. Coating the first structural adhesive layer on the area where the first nanowire 112 and the second nanowire 122 are connected can ensure the connection strength of the first nanowire 112 and the second nanowire 122.

[0135] In the embodiment of the present application, the thickness of the first coating layer 111 is 2-10 μm, the diameter of the first nanowire 112 is 30 nm-2 μm, and the length is 0.5-50 μm. The thickness of the second coating layer 121 is 2-10 μm, and the diameter of the second nanowire 122 is 30 nm-2 μm, and the length is 0.5-50 μm.

[0136] See also Fig.10 As shown, in step S905, the second frame 12 is arranged around the outer periphery of the first frame 11, which may include: the second frame 12 is sleeved on the first frame 11. Specifically, the first frame 11 and the second frame 12 have the same shape, and the second frame 12 may be as follows: Fig.10 As shown in the closed ring shape, the second frame 12 can be sleeved on the outer circumference of the first frame 11.

[0137] In a possible implementation, the height of the second frame 12 expands differently at different temperatures. Specifically, when at room temperature, the height of the inner side of the second frame 12 is less than the height of the outer side of the first frame 11. When the second frame 12 is heated, the height of the inner side of the second frame 12 is greater than the height of the outer side of the first frame 11. At this time, the method of sleeve-mounting the second frame 12 on the first frame 11 specifically includes: heating the second frame 12, sleeve-mounting the second frame 12 on the periphery of the first frame 11. Since the height of the inner side of the second frame 12 is less than the height of the outer side of the first frame 11 when the second frame 12 is cooled to room temperature, the second frame 12 is clamped on the periphery of the first frame 11, which helps to improve the connection strength between the first frame 11 and the second frame 12.

[0138] In addition, when the second frame 12 is cooled back to room temperature, both the first frame 11 and the second frame 12 will undergo elastic deformation, and under the action of the internal stress of the first frame 11 and the second frame 12, a self-pressurized connection can occur. Therefore, cooling the second frame 12 to room temperature can achieve a nano-connection between the first frame 11 and the second frame 12 without pressurization.

[0139] The following is a specific embodiment to illustrate the arrangement of the first frame 11 and the second frame 12:

[0140] The first frame 11 is made of 7075 aluminum alloy, which has a yield strength of 500 MPa, an elastic modulus of 70 Gpa, and an expansion coefficient of 2.4×10 -6 K -1 , see Figure 6 As shown, the outer height of the first frame 11 is H1. The second frame 12 is made of 6061 aluminum alloy, the yield strength of the material is 220MPa, the elastic modulus is 70Gpa, and the expansion coefficient is 2.3×10 -6 K -1 , the inner height of the second frame 12 is H2. At room temperature, H1>H2, for example, H1=(1+0.2%)H2. Then, the second frame 12 is heated to 220°C. According to the expansion coefficient of the 6061 aluminum alloy used in the second frame 12, at 220°C: H 2(220) =(1+0.51%)H2, so H1 <H 2(220) , the second frame 12 can be mounted on the outer periphery of the first frame 11. After the second frame 12 and the first frame 11 are air-cooled back to room temperature, the internal stress of the first frame 11 and the second frame 12 due to elastic deformation is approximately 100 MPa, thereby realizing a self-pressurized connection between the first frame 11 and the second frame 12.

[0141] The specific implementation scheme is as follows: first, a first coating 111 is formed on the side of the first frame 11 facing the second frame 12, and a second coating 121 is formed on the side of the second frame 12 facing the first frame 11, and then, first nanowires 112 and second nanowires 122 are grown on the surfaces of the first coating 111 and the second coating 121, respectively, and the second frame 12 is heated, and the first frame 11 is inserted into the second frame 12, and cooled back to room temperature, and the first nanowires 112 and the second nanowires 122 are self-pressurized and welded together while the temperature is lowered to form a composite frame. In another implementation scheme, as Fig.10 As shown, the middle plate 14 is connected to the inner wall of the first frame 11 via the nano plastic part 15 , for example, the inner wall of the frame 18 is connected to the middle plate 14 by plastic injection molding.

[0142] See also Fig.11As shown, in step S905, the specific method of setting the second frame 12 around the periphery of the first frame 11 can also be: the second frame 12 is attached to the first frame 11 along the periphery of the first frame 11. Specifically, the second frame 12 can be in a strip shape, starting from one end of the second frame 12, and sequentially attached to the first frame 11 along the periphery of the first frame 11, and pressure welding is performed while attaching, so that the second frame 12 is surrounded on the periphery of the first frame 11.

[0143] Among them, the specific implementation scheme is: first, a first coating 111 is formed on a side of the first frame 11 facing the second frame 12, and a second coating 121 is formed on a side of the second frame 12 facing the first frame 11, and then a first nanowire 112 and a second nanowire 122 are grown on the surfaces of the first coating 111 and the second coating 121 respectively, and with one end of the second frame 12 as the starting point, the second frame 12 is sequentially attached to the surface of the first frame 11 along the outer peripheral sides of the first frame 11, and pressure welding is performed while attaching to connect the first nanowire 112 and the second nanowire 122 to form a composite middle frame 10.

[0144] In the embodiment of the present application, after the pressurized connection in step S905, the method further includes:

[0145] Processing the pressurized composite middle frame through a CNC machine tool;

[0146] Cutting the antenna seam, and forming a nano-injection molded part 15 by injection molding on the inner side of the first frame and in the antenna seam;

[0147] The outer surface of the second frame is ground and polished.

[0148] Through the above steps, the antenna seam is cut on the middle frame 10, a nano-injection molded part 15 for connection is formed on the middle frame 10, and the outer surface of the second frame 12 is pre-treated for anodizing, thereby obtaining the formed middle frame 10. It should be noted that in this embodiment, the inner wall of the first frame 11 can be connected to the middle plate 14 before anodizing, or the inner wall of the first frame 11 can be connected to the middle plate 14 after anodizing.

[0149] Embodiment 4

[0150] The method for manufacturing a middle frame provided in the embodiment of the present application is different from that in the third embodiment in that the second frame 12 is bonded to the outer periphery of the first frame 11 by nano-connection. Fig.12 As shown, it may include:

[0151] S120: forming a first plating layer on a side of the first frame facing the second frame by electroplating;

[0152] S121: forming a second plating layer on a side of the second frame facing the first frame by electroplating;

[0153] S122: growing a first nanowire and a second nanowire on two sides of the middle layer respectively;

[0154] S123: The middle layer is placed between the first frame and the second frame, so that the second frame is arranged around the periphery of the first frame, and the first nanowire is close to the first frame, and the second nanowire is close to the second frame, and they are pressurized and connected.

[0155] Through the above process, the first nanowire 112 of the intermediate layer 131 can be connected to the first coating 111 on the first frame 11 by pressurized connection, and the second nanowire 122 of the intermediate layer 131 can be connected to the second coating 121 on the second frame 12, thereby realizing nano-connection between the first frame 11 and the second frame 12 through the intermediate layer 131, and setting the second frame 12 on the periphery of the first frame 11.

[0156] In addition, compared with the connection step of attaching the second frame 12 to the outer periphery of the first frame 11 by nano-connection in Example 3, the connection between the first frame 11 and the second frame 12 is achieved through the intermediate layer 131 in Example 4, and it is more convenient and less difficult to form the first nanowires 112 and the second nanowires 122 on both sides of the intermediate layer 131. Therefore, this solution requires fewer steps and has a lower process difficulty.

[0157] The connection temperature of the pressurized connection is room temperature-250°C, the connection pressure is 15-50MPa, and the connection time is 60ms-60s. In a possible implementation, the connection temperature is room temperature. After the pressurized connection in the above step S123, the method further includes: coating a second structural adhesive layer on the area where the first nanowire 112 is connected to the first coating layer 111 and the area where the second coating layer 121 is connected to the second nanowire 122 to ensure the connection strength between the first nanowire 112 and the first coating layer 111 and between the second nanowire 122 and the second coating layer 121.

[0158] In the embodiment of the present application, the thickness of the intermediate layer 131 is 10-100 μm.

[0159] The step S123 of making the second frame 12 surround the outer periphery of the first frame 11 specifically includes: making the second frame 12 sleeved on the first frame 11. Specifically, the first frame 11 and the second frame 12 have the same shape, the second frame 12 can be annular, and the second frame 12 sleeved on the outer periphery of the first frame 11.

[0160] The specific implementation scheme is as follows: first, a first coating 111 is formed on a side of the first frame 11 facing the second frame 12, and a second coating 121 is formed on a side of the second frame 12 facing the first frame 11, and then a first nanowire 112 and a second nanowire 122 are grown on both sides of the intermediate layer 131, the second frame 12 is heated, the intermediate layer 131 is placed between the first frame 11 and the second frame 12, and the intermediate layer 131 is cooled back to room temperature, and while cooling, self-pressurization welding between the first nanowire 112 and the first coating 111 and between the second nanowire 122 and the second coating 121 is completed to form a composite middle frame 10.

[0161] In step S123, the specific method of setting the second frame 12 around the periphery of the first frame 11 can also be: the second frame 12 is set on the first frame 11 along the periphery of the first frame 11. Specifically, the second frame 12 can be in a strip shape, starting from one end of the second frame 12, and sequentially attached to the first frame 11 along the periphery of the first frame 11.

[0162] The specific implementation scheme is as follows: first, a first coating 111 is formed on a side of the first frame 11 facing the second frame 12, and a second coating 121 is formed on a side of the second frame 12 facing the first frame 11. Then, a first nanowire 112 and a second nanowire 122 are grown on both sides of an intermediate layer 131. The intermediate layer 131 is placed on the periphery of the first frame 11, and starting from one end of the second frame 12, the intermediate layer 131 is sequentially attached to the surface of the first frame 11 along the peripheral sides of the first frame 11. The attachment is pressurized and welded at the same time to connect the first nanowire 112 and the first coating 111 as well as the second nanowire 122 and the second coating 121 to form a composite middle frame 10.

[0163] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0164] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the embodiments of the present application have been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A middle frame, characterized in that: include: The middle frame includes a frame, the frame includes a first frame and a second frame, the second frame is arranged on the outer periphery of the first frame, wherein the molding material of the first frame and the second frame is an aluminum alloy, and the alloy composition of the second frame is less than the alloy composition of the first frame, and the side of the second frame facing away from the first frame is an anodized surface; The invention also includes: a nano-connection layer, the nano-connection layer is located between the first frame and the second frame, and the nano-connection layer is used to make the second frame fit on the first frame; The first frame has a first coating on one side facing the second frame, the second frame has a second coating on one side facing the first frame, the first coating has a first nanowire, the second coating has a second nanowire, the first nanowire and the second nanowire are connected to form the nano connection layer; or The nano-connection layer includes an intermediate layer, the intermediate layer has a first nanowire on a surface facing the first frame, the intermediate layer has a second nanowire on a surface facing the second frame, a first coating layer is provided on a surface of the first frame facing the intermediate layer, a second coating layer is provided on a surface of the second frame facing the intermediate layer, the first coating layer is connected to the first nanowire, and the second coating layer is connected to the second nanowire.

2. The middle frame according to claim 1, characterized in that: The method further includes a first structural adhesive layer, wherein the first structural adhesive layer covers the area where the first nanowire and the second nanowire are connected.

3. The middle frame according to claim 1, characterized in that: It also includes a second structural adhesive layer, which covers an area where the first coating layer and the first nanowire are connected and an area where the second coating layer and the second nanowire are connected.

4. The middle frame according to claim 1 or 3, characterized in that: The thickness of the intermediate layer is 10-100 μm.

5. The middle frame according to claim 1, characterized in that: The thickness of the first coating layer is 2-10 μm, the diameter of the first nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

6. The middle frame according to any one of claims 1 or 5, characterized in that: The thickness of the second coating layer is 2-10 μm, the diameter of the second nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

7. The middle frame according to any one of claims 1 to 6, characterized in that: The material of the nano-connection layer includes copper, gold, nickel, silver, platinum or tin.

8. The middle frame according to any one of claims 1 to 7, characterized in that: The yield strength of the middle frame is greater than or equal to 450 MPa.

9. The middle frame according to any one of claims 1 to 8, characterized in that: The middle frame further includes: a middle plate, the first frame is arranged around the outer edge of the middle plate, and the middle plate is connected to the inner wall of the first frame.

10. A method for manufacturing a middle frame, characterized in that: The middle frame includes a frame, and the frame includes a first frame and a second frame. The manufacturing method includes: The second frame is arranged on the outer periphery of the first frame; wherein the molding material of the first frame and the second frame is aluminum alloy, and the alloy composition of the second frame is less than the alloy composition of the first frame; Performing anodizing treatment on a side of the second frame facing away from the first frame, so that the side of the second frame facing away from the first frame is an anodized surface; The second frame is arranged around the outer periphery of the first frame, comprising: The second frame is bonded to the outer periphery of the first frame by nano-connection; The second frame is bonded to the outer periphery of the first frame by nano-connection, and includes: forming a first plating layer on a side of the first frame facing the second frame by electroplating; forming a second plating layer on a side of the second frame facing the first frame by electroplating; Growing a first nanowire on the surface of the first coating; Growing a second nanowire on the surface of the second coating; The second frame is arranged around the outer periphery of the first frame and connected by pressure; Alternatively, the second frame is bonded to the outer periphery of the first frame by nano-connection, including: forming a first plating layer on a side of the first frame facing the second frame by electroplating; forming a second plating layer on a side of the second frame facing the first frame by electroplating; Growing a first nanowire and a second nanowire on two sides of the middle layer respectively; The intermediate layer is placed between the first frame and the second frame, the second frame is arranged around the periphery of the first frame, the first nanowire is close to the first frame, the second nanowire is close to the second frame, and they are connected by pressure.

11. The method according to claim 10, characterized in that The connection temperature of the pressurized connection is room temperature-250° C., the connection pressure is 15-50 MPa, and the connection time is 60 ms-60 s.

12. The method according to claim 10, characterized in that The thickness of the intermediate layer is 10-100 μm.

13. The method according to claim 10, characterized in that The thickness of the first coating layer is 2-10 μm, the diameter of the first nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

14. The method according to claim 10, characterized in that The thickness of the second coating layer is 2-10 μm, the diameter of the second nanowire is 30 nm-2 μm, and the length is 0.5-50 μm.

15. The method according to claim 11, characterized in that When the connection temperature is room temperature, after the pressurized connection, the method further comprises: A first structural adhesive layer is coated on a region where the first nanowire and the second nanowire are connected.

16. The method according to claim 11, characterized in that When the connection temperature is room temperature, after the pressurized connection, the method further comprises: A second structural adhesive layer is coated on a region where the first nanowire is connected to the first plating layer and a region where the second plating layer is connected to the second nanowire.

17. The method according to any one of claims 10 to 16, characterized in that: The step of making the second frame surround the periphery of the first frame comprises: The second frame is sleeved on the first frame; or the second frame is disposed on the first frame along the outer periphery of the first frame.

18. The method according to claim 17, characterized in that When at room temperature, the inner height of the second frame is less than the outer height of the first frame, and when the second frame is heated, the inner height of the second frame is greater than the outer height of the first frame, wherein the second frame is sleeved on the first frame comprises: Heating the second frame and sleeve the second frame on the outer periphery of the first frame; The pressurized connection includes: cooling the second frame to room temperature.

19. The method according to any one of claims 10 to 18, characterized in that: The pressurized connection also includes: Processing the pressurized composite middle frame through a CNC machine tool; Cutting the antenna seam, and forming a nano-injection molded part by injection molding on the inner side of the first frame and in the antenna seam; The outer surface of the second frame is ground and polished.

20. The method according to any one of claims 10 to 19, characterized in that: After the anodizing treatment is performed on the side of the second frame facing away from the first frame, the method further comprises: Provide mid-board; Connect the outer edge of the middle plate to the inner wall of the first frame.

21. A middle frame, characterized in that: The middle frame is manufactured by the method according to any one of claims 10-20.

22. An electronic device, characterized in that: include: A display screen, a back cover and the middle frame described in claim 21 or the middle frame described in any one of claims 1 to 9, wherein the middle frame is located between the display screen and the back cover.

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