Circuit board assembly and electronic device

Abstract

The circuit board assembly and the electronic equipment provided by the embodiment of the present application are applied to the technical field of electronic equipment. The circuit board assembly comprises a circuit board, an electronic device and a sealing structure. The electronic device comprises a device body and a connecting pin. The connecting pin is welded with the circuit board to form a welding point. In the thickness direction of the circuit board, there is a gap between the device body and the circuit board. The sealing structure surrounds the electronic device and is connected with the electronic device and the circuit board respectively. The sealing structure blocks the gap and covers the welding point. The sealing structure comprises a hydrophobic layer, and the hydrophobic layer blocks at least part of the gap. In this way, sweat or rainwater can be prevented from entering the interior of the switch device, and problems such as electrode corrosion or short circuit of the switch device can be prevented.

Description

Technical Field

[0001] This application relates to the field of electronic equipment technology, and more particularly to a circuit board assembly and an electronic device. Background Technology

[0002] Electronic devices such as mobile phones and smartwatches typically include button components, such as power buttons and volume buttons. In related technologies, the electronic device includes a frame and a button assembly. The frame has button holes, and the button assembly is installed within these holes. Part of the button assembly is located inside the electronic device, while another part extends out of the button hole, allowing the user to operate it. However, when the button assembly is pressed, liquids such as sweat or rainwater can easily enter the switching device through the gap between the button assembly and the inner wall of the button hole, causing problems such as electrode corrosion or short circuits. Summary of the Invention

[0003] This application provides a circuit board assembly and an electronic device, applicable to the field of electronic device technology. This electronic device can prevent sweat or rainwater from entering the internal components during switching, thus preventing problems such as electrode corrosion or short circuits in the switching device.

[0004] In a first aspect, embodiments of this application provide a circuit board assembly, which includes a circuit board, electronic components, and a sealing structure. The electronic component includes a component body and connecting pins, the connecting pins being soldered to the circuit board to form solder joints. A gap exists between the component body and the circuit board along the thickness direction of the circuit board. The sealing structure surrounds the electronic component and is connected to both the electronic component and the circuit board. The sealing structure seals the gap and covers the solder joints. The sealing structure includes a hydrophobic layer that seals at least a portion of the gap.

[0005] In this embodiment, when the electronic device is a switching device and is applied to a narrow circuit board, the dispensing space on at least one side of the device body along the width direction of the circuit board is less than 0.5 mm. For example, when the dispensing space on both sides of the device body along the width direction of the circuit board is less than 0.5 mm, hydrophobic material can be applied to the surface film of the device body. Under the action of gravity, the hydrophobic material flows to the gap between the device body and the circuit board on both sides of the width direction of the circuit board. The hydrophobic layer formed by curing seals the gap between the device body and the circuit board on both sides of the width direction of the circuit board, thereby sealing the device body on both sides of the width direction of the circuit board. This prevents liquids such as sweat and rainwater from entering the interior of the switching device through the gap between the device body and the circuit board on either side of the width direction of the circuit board, thus avoiding problems such as electrode corrosion or short circuits.

[0006] Furthermore, when another portion of the hydrophobic layer covers part of the surface film of the device body, due to the thinness of the hydrophobic layer, it has little or no impact on the tactile feel or electrical connection pathways of the device body. In addition, compared to using UF adhesive to seal the gap between the device body and the circuit board, the amount of hydrophobic material used to form the hydrophobic layer is less, reducing processing costs. Finally, by controlling the solvent type of the hydrophobic material, it can achieve rapid curing at room temperature or low temperature, compared to the high-temperature curing required for UF adhesive, thus reducing processing difficulty.

[0007] In one possible implementation, the hydrophobic layer's orthographic projection on the circuit board is a ring structure, surrounding the device body. The first part of the hydrophobic layer seals gaps, and the second part covers solder joints. In this way, the hydrophobic layer constitutes the entire sealing structure, simplifying the sealing structure, reducing manufacturing steps, and improving production efficiency.

[0008] In one possible implementation, the sealing structure further includes a sealing colloid, which is connected to the device body, the circuit board, and the hydrophobic layer, respectively, and covers the solder joints. Thus, sealing the solder joints with the sealing colloid improves the sealing effect.

[0009] In one possible implementation, a hydrophobic layer seals the gaps.

[0010] In one possible implementation, a first portion of the sealant covers the weld joint, a second portion of the sealant covers a portion of the gap, and a hydrophobic layer seals another portion of the gap.

[0011] In one possible implementation, the hydrophobic layer's orthographic projection onto the circuit board is a ring structure, with the hydrophobic layer surrounding the device body and a portion of it covering a sealing colloid. This reduces the manufacturing difficulty and improves the production efficiency of the hydrophobic layer.

[0012] In one possible implementation, the thickness of the hydrophobic layer is greater than or equal to 1 nm and less than or equal to 20 μm. This makes the hydrophobic layer very thin, so that it does not affect the tactile feel or electrical connectivity.

[0013] In one possible implementation, the hydrophobic layer is made of silicon-based polymer hydrophobic materials or fluorine-based hydrophobic materials.

[0014] In one possible implementation, the hydrophobic layer is made of dimethylsiloxane, vinylsiloxane, methoxy-nonafluorobutane, perfluoroalkyl acrylate, or fluorohydroether.

[0015] In one possible implementation, the hydrophobic layer is formed by curing a hydrophobic material with a solid content of less than or equal to 30 wt%.

[0016] In one possible implementation, along the width direction of the circuit board, the distance between at least one of the opposite sides of the device body and the edge of the circuit board is less than 0.5 mm. Thus, by having a solid content of less than or equal to 30 wt% for the hydrophobic material, the hydrophobic material has a low degree of cross-linking, resulting in a very thin hydrophobic layer that does not affect the tactile feel or electrical connection pathways. Furthermore, the processing difficulty of the hydrophobic material can be reduced; for example, it can be processed using methods such as jet valve dispensing, pneumatic valve spraying, or atomized deposition.

[0017] In one possible implementation, the width of the circuit board is less than or equal to 4mm, which makes the circuit board narrower, reduces the impact on the thickness of the electronic device, and helps to achieve a thinner design for the electronic device.

[0018] In one possible implementation, the circuit board is a flexible circuit board. This reduces the space occupied by the circuit board by bending it, and also simplifies the connection between the circuit board and the motherboard of the electronic device.

[0019] In one possible implementation, the electronic device is a switch, resistor, capacitor, or connector.

[0020] In one possible implementation, the electronic device is a switching device, and the device body includes a mounting base, a surface film, a movable contact, a fixed contact, and a push plate. The mounting base forms a gap with the circuit board, and the mounting base and the surface film enclose a mounting space. The fixed contact, movable contact, and push plate are all located inside the mounting space. Along the thickness direction of the circuit board, the push plate is located between the surface film and the movable contact. The push plate and the fixed contact are located on opposite sides of the movable contact. The fixed contact is fixedly connected to the mounting base and electrically connected to the circuit board. One end of a connection pin is located outside the mounting space, and the other end of the connection pin is electrically connected to the fixed contact.

[0021] Secondly, embodiments of this application provide an electronic device that includes a circuit board assembly as described in any of the first aspects.

[0022] In one possible implementation, the electronic device includes a mid-frame and a button assembly. The mid-frame has button holes. The button assembly includes a button component and a circuit board assembly. The electronic component of the circuit board assembly is a switching device. One end of the button component protrudes to the outside of the electronic device through the button hole, and the other end of the button component is used to activate the switching device.

[0023] It should be understood that the second aspect of this application corresponds to the technical solution of the first aspect of this application, and the beneficial effects achieved by each aspect and the corresponding feasible implementation are similar, and will not be repeated here. Attached Figure Description

[0024] Figure 1This is a schematic diagram of an electronic device provided in an embodiment of this application;

[0025] Figure 2 for Figure 1 An exploded view of the electronic device shown.

[0026] Figure 3 A cross-sectional schematic diagram of a button assembly provided in an embodiment of this application;

[0027] Figure 4 for Figure 3 A cross-sectional view of the switch element 120 in the diagram;

[0028] Figure 5 This is a schematic diagram of a UF adhesive dispensing path in related technologies;

[0029] Figure 6 for Figure 5 A top view of the first sealant formed by the curing of UF adhesive and its mating with the device body;

[0030] Figure 7 for Figure 6 The diagram shows a side view of the first sealing material in conjunction with the device body and the circuit board.

[0031] Figure 8 This is a schematic diagram of the UF adhesive dispensing path after the circuit board width becomes narrower;

[0032] Figure 9 for Figure 8 A top view of the UF adhesive after curing and its fit with the device body;

[0033] Figure 10 for Figure 9 A side view diagram showing the UF adhesive in conjunction with the device body and the circuit board;

[0034] Figure 11 A top view schematic diagram of a circuit board assembly provided in an embodiment of this application;

[0035] Figure 12 for Figure 11 A cross-sectional view along the AA direction;

[0036] Figure 13 for Figure 12 Cross-sectional view along the BB direction;

[0037] Figure 14 A cross-sectional schematic diagram of another circuit board assembly provided in an embodiment of this application;

[0038] Figure 15 In order to be in Figure 11 A schematic diagram showing the route for coating a hydrophobic material on a narrow circuit board;

[0039] Figure 16 A top view schematic diagram of another circuit board assembly provided in an embodiment of this application;

[0040] Figure 17 for Figure 16 A cross-sectional view along the CC direction;

[0041] Figure 18 In order to be in Figure 15 The diagram shows the route for coating hydrophobic material and applying UF adhesive on a narrow circuit board.

[0042] 100. Button assembly;

[0043] 110. Keypad; 111. Keycap; 112. Actuator;

[0044] 120. Switching component; 121. Switching device; 1211. Mounting base; 1212. Surface film; 1213. Moving contact; 1214. Fixed contact; 1215. Push plate;

[0045] 200. Mid-frame; 210. Button hole;

[0046] 300. Display screen;

[0047] 400. Battery cover;

[0048] 500. Circuit board assembly;

[0049] 510. Circuit board;

[0050] 520. Electronic components; 521. Component body;

[0051] 530. Solder joint;

[0052] 540, hydrophobic layer; 550, sealing colloid;

[0053] 600, gap. Detailed Implementation

[0054] Figure 1 This is an overall schematic diagram of an electronic device provided in an embodiment of this application. Figure 2 for Figure 1 An exploded view of the electronic device shown.

[0055] refer to Figure 1 and Figure 2As shown, this application embodiment provides an electronic device, which includes a button assembly 100 and a mid-frame 200. The button assembly 100 is disposed on the outer wall of the mid-frame 200. The outer wall of the mid-frame 200 can be understood as the sidewall of the mid-frame 200 exposed on the surface of the electronic device. For example, the button assembly 100 may include, but is not limited to, a power button and volume buttons. Generally, the mid-frame 200 has a middle plate and a frame, with the frame surrounding the peripheral edge of the middle plate and forming the mid-frame 200 together. The button assembly 100 may be disposed on the frame. The frame may include a left frame, a top frame, a right frame, and a bottom frame, which may be connected end-to-end to form a ring-shaped frame.

[0056] For example, the button assembly 100 can be disposed on the right side border. Alternatively, in some embodiments, the button assembly 100 can also be disposed in other locations on the border, such as the left side border. By disposing of the button assembly 100 on the border, the structure of the border, such as the right side border, can be utilized in a reasonable manner, and while realizing the function of the button assembly 100 of the electronic device, it can also better conform to the user's operating habits.

[0057] In this embodiment, the electronic device may include, but is not limited to, any electronic device with a mid-frame 20020 and requiring button component 100 functionality, such as a mobile phone, tablet computer (i.e., pad), laptop computer, ultra-mobile personal computer (UMPC), handheld computer, walkie-talkie, netbook, POS machine, personal digital assistant (PDA), wearable device, virtual reality device, etc.

[0058] The structure of the electronic device in this embodiment will be further described below, taking the button assembly 100 set in a mobile phone as an example.

[0059] like Figure 2 As shown, electronic devices such as mobile phones may also include a display screen 300 and a battery cover 400, which are connected to the opposite sides of the mid-frame 200. Generally, the display screen 300 and the battery cover 400 can be connected to the mid-frame 200 by means of adhesive bonding.

[0060] It should be noted that in this embodiment... Figure 2 The structures shown do not constitute a limitation on the structure of electronic devices. Electronic devices may also include, in addition to Figure 2Other structures shown include the motherboard, battery, and camera. The configuration of the battery, camera, and motherboard in electronic devices such as mobile phones can refer to the configuration within related mobile phones, and will not be further limited in this embodiment.

[0061] Figure 3 This is a cross-sectional schematic diagram showing the cooperation between a button assembly and a middle frame, as provided in an embodiment of this application.

[0062] For example, such as Figure 3 As shown, the button assembly 100 includes a button 110 and a switch 120. The mid-frame 200 has a button hole 210. One end of the button 110 protrudes from the outside of the electronic device through the button hole 210, and the other end of the button assembly 100 is used to turn on the switch 120, causing the switch 120 to generate an electrical signal. In actual implementation, when the user presses the button 110, the button 110 moves towards the switch 120, applying force to the switch 120, causing the switch 120 to turn on and generate an electrical signal.

[0063] In some embodiments, such as Figure 3 As shown, the key component 110 includes a keycap 111 and an actuator 112. A portion of the keycap 111 is located inside the keyhole 210, while the other portion protrudes from the outside of the electronic device. One end of the actuator 112 is connected to the keycap 111. When the user presses the keycap 111, the keycap 111 moves towards the switch component 120 and pushes the actuator 112 to move. The actuator 112 applies force to the switch component 120, causing the switch component 120 to conduct.

[0064] Figure 4 for Figure 3 A cross-sectional view of the switch element 120.

[0065] For example, such as Figure 4 As shown, the switch 120 includes a switch device 121 and a circuit board 510. The switch device 121 is electrically connected to the circuit board 510. The switch device 121 has an on state and an off state. By pressing the button 110, a force is applied to the switch device 120, causing the switch device 121 to switch from the off state to the on state. When the switch device 121 is in the on state, it conducts and generates an electrical signal. When the switch device 121 is in the off state, it is off and does not generate an electrical signal. In practical applications, the switch device 121 is usually in the off state; that is, the switch device 120 is not conducting when the button 110 is not pressed.

[0066] In some embodiments, such as Figure 4As shown, the switching device 121 includes a device body 521 and connection pins (not shown in the figure). The device body 521 and the circuit board 510 are aligned in the thickness direction of the circuit board 510 (e.g., ...). Figure 4 A gap 600 is provided in the Y direction, and a connecting pin is soldered to the circuit board 510 to form a solder joint 530. At least a portion of the solder joint 530 is located outside the gap 600, for example... Figure 4 As shown, part of the solder joint 530 is located inside the gap 600 and another part is located outside the gap 600. Of course, all of the solder joints 530 can also be located outside the gap 600.

[0067] It is understood that at least a portion of solder joint 530 being located outside the gap 600 can be understood as at least a portion of solder joint 530 not being sandwiched between device body 521 and circuit board 510.

[0068] For example, such as Figure 4 As shown, the device body 521 includes a mounting base 1211, a surface film 1212, a movable contact 1213, a fixed contact 1214, and a push plate 1215. The mounting base 1211 forms a gap 600 with the circuit board 510. The mounting base 1211 and the surface film 1212 enclose a mounting space. The fixed contact 1214, the movable contact 1213, and the push plate 1215 are all located inside the mounting space, along the thickness direction of the circuit board 510 (e.g., ...). Figure 4 In the Y direction, push plate 1215 is located between surface film 1212 and movable contact 1213. Push plate 1215 and fixed contact 1214 are located on opposite sides of movable contact 1213. Fixed contact 1214 is fixedly connected to mounting base 1211 and electrically connected to circuit board 510. One end of connection pin is located outside the mounting space, and the other end of connection pin is electrically connected to fixed contact 1214.

[0069] The number of active contacts 1213 can be one or more, for example... Figure 4 As shown, there are three active contacts 1213, and these three active contacts 1213 are located along the thickness direction of the circuit board 510 (e.g., ...). Figure 4 (Y-direction) stacking settings.

[0070] like Figure 3As shown, due to the clearance fit between the button component 110 and the inner wall of the button hole 210, there is a gap between the button component 110 and the inner wall of the button hole 210. When the button component 110 is pressed, external liquids such as sweat or rainwater can easily flow through the gap between the inner wall of the button component 110 and the button hole 210 to the vicinity of the switching device 121, and enter the interior of the mounting base 1211 through the gap 600 between the device body 521 and the circuit board 510. This causes the liquids such as sweat or rainwater to come into contact with electrodes such as the fixed contact 1214 or the movable contact 1213, resulting in problems such as electrode corrosion or short circuits. In addition, they may also come into contact with the solder joint 530, causing problems such as corrosion or migration of the solder joint 530, resulting in the overall malfunction of the switching device 121.

[0071] Figure 5 This is a schematic diagram of a UF adhesive dispensing path in related technologies. Figure 6 for Figure 5 A top view schematic diagram of the first sealant formed by the curing of UF adhesive and its mating with the device body. Figure 7 for Figure 6 The diagram shows a side view of the first sealing material in conjunction with the device body and the circuit board.

[0072] In one related technology, the electronic device further includes a sealing structure that covers the exposed portion of the solder joint 530 and seals the gap 600 between the device body 521 and the circuit board 510. The sealing structure includes a first sealing element and a second sealing element. The first sealing element is an annular structure and is fitted onto the device body 521 of the switching device 1221. The first sealing element seals the gap 600 between the device body 521 and the circuit board 510, preventing liquid from entering the device electrodes through the gap 600. The second sealing element covers the exposed portion of the solder joint 530 located outside the gap 600.

[0073] The first sealant is made of epoxy resin adhesive (Underfill, or UF for short) cured, along... Figure 5 The UF adhesive dispensing path shown applies a ring of epoxy resin adhesive around the device body 521 of the switch device 121, bonding... Figure 6 and Figure 7 It can be seen that after the UF adhesive cures, it forms the first sealing adhesive to seal the gap 600 between the device body 521 and the circuit board 510.

[0074] The second sealant is formed by applying UV-curing adhesive to the weld joint 530. The UV-curing adhesive can be applied before or after the formation of the first sealant.

[0075] Figure 8This is a schematic diagram of the UF adhesive dispensing path after the circuit board width becomes narrower. Figure 9 for Figure 8 A top view of the UF adhesive after curing and its mating with the device body. Figure 10 for Figure 9 A side view diagram showing the UF adhesive in conjunction with the device body and the circuit board.

[0076] However, as the thickness of the mobile phone decreases, the width of the circuit board 510 in the thickness direction of the electronic device correspondingly narrows, resulting in the distance between at least one side of the device body 521 of the switching device 121 and the edge of the circuit board 510 along the width direction being less than 0.5 mm, for example. Figure 8 As shown, along the width direction of circuit board 510 (e.g.) Figure 8 (Z-direction), the distance between the device body 521 and the circuit board 510 on one side of the circuit board 510 in the width direction (e.g., in the Z-direction), and the circuit board 510. Figure 8 The diameter (L shown in the image) is less than 0.5mm, resulting in insufficient space for the UF adhesive on that side. Consequently, the UF adhesive cannot be completely filled on that side. Figure 9 and Figure 10 It is known that the gap 600 between the device body 521 and the circuit board 510 cannot be completely sealed. After prolonged contact with liquid, the solder joint 530 corrodes or migrates, causing overall malfunction. In addition, liquid can easily enter the interior of the switching device 121, causing problems such as electrode corrosion or short circuits.

[0077] When there is insufficient space to apply the UF adhesive, in one embodiment, the UF adhesive can be applied to the surface film 1212 of the device body 521. The UF adhesive flows to the gap 600 between the device body 521 and the circuit board 510, and then cures to form a first sealant. However, because the cured UF adhesive is relatively thick and has very low flexibility, it restricts the movement of the surface film 1212, thereby affecting the pressing feel and even affecting the electrical connection path formed by the fixed contact 1214 and the movable contact 1213.

[0078] In view of this, embodiments of this application provide a circuit board assembly 500, which includes a circuit board 510, an electronic device 520, and a hydrophobic layer 540. The electronic device 520 is formed by a device body 521 and connection pins, and the device body 521 and the circuit board 510 have a gap 600 in the thickness direction of the circuit board 510. By coating the periphery of the device body 521 with a volatile solvent-based hydrophobic material, the hydrophobic material cures to form a hydrophobic layer 540, which seals at least a portion of the gap 600 between the device body 521 and the circuit board 510. Since the solvent in the hydrophobic material evaporates after curing, the thickness of the hydrophobic layer 540 is thin. Therefore, the portion of the surface film 1212 covered by the hydrophobic layer 540 will not affect the pressing feel or the electrical connection path. Therefore, by sealing at least a portion of the gap 600 between the device body 521 and the circuit board 510 through the hydrophobic layer 540, it can be applied to scenarios where the circuit board 510 is narrowed, which helps to achieve the thinning design of electronic devices.

[0079] The circuit board assembly 500 provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0080] Figure 11 This is a top view schematic diagram of a circuit board assembly provided in an embodiment of this application. Figure 12 for Figure 11 A cross-sectional view along the AA direction. Figure 13 for Figure 12 A cross-sectional view along the BB direction.

[0081] See Figure 11 The circuit board assembly 500 includes a circuit board 510, electronic components 520, and a sealing structure. The circuit board 510 is a flexible printed circuit (FPC). By bending the circuit board 510, the space occupied by the circuit board 510 is reduced, and the connection difficulty between the circuit board 510 and the motherboard of the electronic device is also reduced. Of course, in some embodiments, the circuit board 510 can also be a printed circuit board (PCB).

[0082] In one possible implementation, along the width direction of the circuit board 510 (e.g. Figure 11 In the Z-direction, the width of the circuit board 510 is less than or equal to 4mm, which makes the width of the circuit board 510 narrower, reducing the impact on the thickness of the electronic device and helping to achieve a thinner design for the electronic device.

[0083] Of course, in some embodiments, the width of the circuit board 510 may be greater than 4 mm, in addition to being less than or equal to 4 mm.

[0084] Electronic device 520 can be a switch device 121, an electronic component (chip), or a connector, etc. The electronic component can be a resistor, capacitor, etc. For ease of description, the following description takes electronic device 520 as a switch device 121 as an example. In this case, the circuit board assembly 500 constitutes the switch 120 of the button assembly 100 mentioned above.

[0085] It should be noted that when the electronic device 520 is an electronic component or connector, the circuit board assembly 500 can be used not only in the above-mentioned electronic devices such as mobile phones, tablets, laptops, ultra-mobile personal computers (UMPCs), handheld computers, walkie-talkies, netbooks, POS machines, personal digital assistants (PDAs), wearable devices, and virtual reality devices, but also in electronic devices such as servers, switches, and routers.

[0086] In some embodiments, the number of electronic devices 520 is one. In other embodiments, the number of electronic devices 520 can be multiple, for example, the number of electronic devices 520 can be two, in which case two electronic devices 520 are soldered on the circuit board 510.

[0087] Electronic device 520 includes a device body 521 and connection pins. The connection pins are soldered to circuit board 510 to form solder joints 530. Electronic device 120 is fixedly connected to and electrically connected to circuit board 510 via solder joints 530. Along the thickness direction of circuit board 510 (e.g., along the thickness direction of circuit board 510)... Figure 12 (in the Y direction), there is a gap of 600 between the device body 521 and the circuit board 510.

[0088] Each connection pin corresponds one-to-one with a solder joint 530. For example, there are four connection pins; in this case, the four connection pins are soldered to the circuit board 510 to form four solder joints 530 (e.g., ...). Figure 11 (As shown). Of course, the number of connection pins can be less than or more than four, and correspondingly, the number of solder points 530 can also be less than or more than four.

[0089] In some embodiments, along the length direction of the circuit board 510 (e.g.) Figure 11 In the X direction, solder joint 530 is located on at least one of the opposite sides of the device body 521 along the length of the circuit board 510, for example... Figure 11As shown, some solder joints 530 are located on one side of the device body 521 along the length direction of the circuit board 510, and other solder joints 530 are located on the other side of the device body 521 along the length direction of the circuit board 510. In this way, the width of the circuit board assembly 500 in the width direction of the circuit board 510 can be reduced, which helps to achieve a thinner design for electronic devices.

[0090] In one possible implementation, along the width direction of the circuit board 510, the distance between at least one of the opposite sides of the device body 521 along the width direction of the circuit board 510 and the edge of the circuit board 510 is less than 0.5 mm, for example... Figure 11 As shown, the distance between the opposite sides of the device body 521 and the edge of the circuit board 510 along the width direction of the circuit board 510 (e.g.) Figure 11 Both M1 and M2 (as shown in the figures) are less than 0.5 mm.

[0091] It should be noted that, along the width direction of the circuit board 510, in some embodiments, the distance between at least one of the opposite sides of the device body 521 along the width direction of the circuit board 510 and the edge of the circuit board 510 may be greater than or equal to 0.5 mm, except that it is less than 0.5 mm.

[0092] In some embodiments, the spacing between the opposite sides of the device body 521 along the width direction of the circuit board 510 and the edge of the circuit board 510 may be the same. In this case, the electronic device 520 is arranged at the center of the circuit board 510 along the width direction of the circuit board 510.

[0093] In other embodiments, the spacing between the opposite sides of the device body 521 along the width direction of the circuit board 510 and the edge of the circuit board 510 may also be different. In this case, the electronic device 520 is closer to the side of the circuit board 510 along the width direction of the circuit board 510.

[0094] For example, when electronic device 520 is a switching device 121, such as Figure 12 or Figure 13As shown, the device body 521 includes a mounting base 1211, a surface film 1212, a movable contact 1213, a fixed contact 1214, and a push plate 1215. The mounting base 1211 forms a gap 600 with the circuit board 510, and the mounting base 1211 and the surface film 1212 enclose a mounting space. The fixed contact 1214, movable contact 1213, and push plate 1215 are all located inside the mounting space. Along the thickness direction of the circuit board 510, the push plate 1215 is located between the surface film 1212 and the movable contact 1213. The push plate 1215 and the fixed contact 1214 are located on opposite sides of the movable contact 1213. The fixed contact 1214 is fixedly connected to the mounting base 1211 and electrically connected to the circuit board 510. One end of the connection pin is located outside the mounting space, and the other end of the connection pin is electrically connected to the fixed contact 1214.

[0095] In practical applications, when a user presses the button 110, the button 110 comes into contact with the surface film 1212 and presses down the push plate 1215. The push plate 1215 causes the movable contact 1213 to deform until the movable contact 1213 connects with the fixed contact 1214, forming a circuit and then an electrical connection is established.

[0096] It should be noted that the opposite sides of the mounting base 1211 along the width direction of the circuit board 510 are the opposite sides of the device body 521 along the width direction of the circuit board 510. At this time, the distance between one side of the mounting base 1211 along the width direction of the circuit board 510 and the edge of the circuit board 510 is the distance between one side of the device body 521 along the width direction of the circuit board 510 and the edge of the circuit board 510.

[0097] In this embodiment, the sealing structure surrounds the electronic device 520 and is connected to both the electronic device 520 and the circuit board 510. The sealing structure seals the gap 600 and covers the solder joint 530, preventing liquids such as sweat and rainwater from entering the interior of the switching device 121 and preventing problems such as electrode corrosion or short circuits. It also prevents corrosion or migration of the solder joint 530, ensuring that the overall function of the switching device 121 remains intact.

[0098] The sealing structure includes a hydrophobic layer 540, which is formed by curing a hydrophobic material based on a volatile solvent. The hydrophobic layer 540 seals at least a portion of the gap 600, for example, by bonding... Figure 12 and Figure 13 It can be seen that the hydrophobic layer 540 seals all gaps 600.

[0099] like Figure 13 As shown, the gap 600 is formed by the mounting base 1211 of the device body 521 and the circuit board 510, so the hydrophobic layer 540 contacts at least the sidewalls of the circuit board 510 and the mounting base 1211, thereby sealing at least a portion of the gap 600.

[0100] Figure 14 This is a cross-sectional schematic diagram of another circuit board assembly provided in an embodiment of this application.

[0101] In some embodiments, such as Figure 14 As shown, the hydrophobic layer 540 can also contact a portion of the surface of the surface film 1212. That is, while the hydrophobic layer 540 is in contact with the sidewalls of the circuit board 510 and the mounting base 1211, it also covers a portion of the surface of the surface film 1212.

[0102] When the width of the circuit board 510 is narrow, the dispensing space on at least one side of the device body 521 along the width direction of the circuit board 510 is less than 0.5 mm. For example, when the dispensing space on both sides of the device body 521 along the width direction of the circuit board 510 is less than 0.5 mm, hydrophobic material can be applied to the surface film 1212 of the device body 521. Under the action of gravity, the hydrophobic material flows to the gap between the device body 521 and the circuit board 510 along the width direction of the circuit board 510. The hydrophobic layer 540 formed by curing seals the gap between the device body 521 and the circuit board 510 along the width direction of the circuit board 510, thereby sealing the device body 521 on both sides of the circuit board 510 in the width direction. This prevents liquids such as sweat and rainwater from entering the interior of the switching device 121 through the gap 600 between the device body 521 and the circuit board 510 on any side of the device body 521 in the width direction of the circuit board 510, thus avoiding problems such as electrode corrosion or short circuits.

[0103] Furthermore, when another portion of the hydrophobic layer 540 covers part of the surface film 1212, due to the thinness of the hydrophobic layer 540, it has little to no impact on the tactile feel or electrical connection pathways of the device body 521. In addition, compared to sealing the gap 600 between the device body 521 and the circuit board 510 with UF adhesive, the amount of hydrophobic material used to form the hydrophobic layer 540 is less, reducing processing costs. Finally, by controlling the solvent type of the hydrophobic material, it can be rapidly cured at room temperature or low temperature, compared to the high-temperature curing required for UF adhesive, thus reducing processing difficulty.

[0104] In one possible implementation, the hydrophobic layer 540 can be made of a silicon-based polymer hydrophobic material, a fluorinated hydrophobic material, or other hydrophobic materials.

[0105] Among them, silicon-based hydrophobic polymers can be dimethylsiloxane, vinylsiloxane, and their derivatives. Fluorine-based hydrophobic materials can be methoxy-nonafluorobutane, perfluoroalkyl acrylates, or fluorohydroethers, etc.

[0106] It is understandable that the uncured hydrophobic material is composed of a base hydrophobic material and a solvent. The base hydrophobic material can be a silicon-based polymer hydrophobic material, a fluorinated hydrophobic material, etc. In some embodiments, to meet the requirements of rapid curing at room temperature or low temperature, the solvent type is selected as a volatile solvent such as methylcyclohexane or n-hexane. Therefore, it can be seen that the hydrophobic layer 540 is composed of the base hydrophobic material in the hydrophobic material.

[0107] In one possible implementation, the hydrophobic layer 540 is formed by curing a hydrophobic material with a solid content of less than or equal to 30 wt%, where solid content refers to the proportion of non-volatile solid components in the hydrophobic material. By setting the solid content of the hydrophobic material to less than or equal to 30 wt%, the hydrophobic material has a low degree of cross-linking, resulting in a very thin hydrophobic layer 540 that does not affect the tactile feel or electrical connectivity. Furthermore, the processing difficulty of the hydrophobic material can be reduced; for example, it can be processed using methods such as jet valve dispensing, pneumatic valve spraying, or atomized deposition.

[0108] It should be noted that, in addition to being formed by curing hydrophobic materials with a solid content of less than or equal to 30 wt%, in some embodiments, the hydrophobic layer 540 can also be formed by curing hydrophobic materials with a solid content of greater than 30 wt% and less than or equal to 50 wt%, which can also form a thinner hydrophobic layer 540, having little impact on the pressing feel and electrical connection path.

[0109] In one possible implementation, the thickness of the hydrophobic layer 540 is greater than or equal to 1 nm and less than or equal to 20 μm, making the hydrophobic layer 540 very thin so that it does not affect the pressing feel and electrical connection path.

[0110] It should be noted that when applying waterproof material, the thickness of the hydrophobic layer 540 can be controlled between 1nm and 20μm by controlling the amount of waterproof material used.

[0111] Of course, in addition to being between 1 nm and 20 μm, the thickness of the hydrophobic layer 540 can also be greater than 20 μm in some embodiments, in order to ensure that the impact on the pressing feel and electrical connection path is minimal.

[0112] In one possible implementation, see Figure 11 The hydrophobic layer 540, projected onto the circuit board 510, is a ring structure. The hydrophobic layer 540 surrounds the device body 521. The first part of the hydrophobic layer 540 seals the gap 600 (e.g., Figure 13 As shown), the second portion of the hydrophobic layer 540 covers the solder joint 530 (as shown). Figure 12 (As shown). It can be seen that the hydrophobic layer 540 constitutes the entire sealing structure, which can simplify the sealing structure, reduce the process steps of the sealing structure, and improve the production efficiency of the sealing structure.

[0113] Figure 15 In order to be in Figure 11 The diagram shows the route for coating a hydrophobic material on a narrow circuit board.

[0114] See Figure 15 As shown, during the fabrication of the sealing structure, a certain amount of waterproof material is applied to the periphery of the device body 521 at the junction with the circuit board 510 using coating processes such as dot coating, spraying, and atomized deposition. Simultaneously, the solder joints 530 are wrapped. After the hydrophobic material cures, the final product is obtained. Figure 11 The circuit board assembly 500 shown here has a hydrophobic layer 540 covering the solder joints 530 and sealing the gaps 600.

[0115] In the above description, the hydrophobic layer 540 forms a sealing structure, sealing the gap 600 while covering the solder joint 530. Of course, the solder joint 530 can also be sealed without the hydrophobic layer 540.

[0116] Figure 16 This is a top view schematic diagram of another circuit board assembly provided in an embodiment of this application. Figure 17 for Figure 16 A cross-sectional view along the CC direction.

[0117] In one possible implementation, combining Figure 16 and Figure 17 As shown, the sealing structure includes a hydrophobic layer 540 and a sealing colloid 550. The hydrophobic layer 540 covers at least a portion of the gap 600. The sealing colloid 550 is formed by curing sealant and is connected to the device body 521, the circuit board 510, and the hydrophobic layer 540, respectively, covering the solder joint 530. Thus, by sealing the solder joint 530 with the sealing colloid 550, the sealing effect of the solder joint 530 is improved.

[0118] In some embodiments, a first portion of the sealant 550 covers the solder joint 530, a second portion of the sealant 550 covers a portion of the gap 600, and the hydrophobic layer 540 seals another portion of the gap 600. In other embodiments, the hydrophobic layer 540 seals the gap 600, in which case the sealant 550 is primarily used to cover the solder joint 530. Therefore, when the sealant 550 covers the solder joint 530, the hydrophobic layer 540 can seal part or all of the gap 600.

[0119] The material of sealant 550 can be epoxy resin adhesive (Underfill adhesive, abbreviated as UF adhesive), UV curing adhesive, and other sealants.

[0120] Combination Figure 16 and Figure 17It is known that the hydrophobic layer 540 is in contact with at least the surface of the circuit board 510 and the sidewall of the mounting base 1211. Additionally, in conjunction with... Figure 16 and Figure 17 It is understood that the hydrophobic layer 540 can also cover part of the surface of the surface film 1212. Of course, in some other embodiments, the hydrophobic layer 540 may not cover the surface of the surface film 1212. When the hydrophobic layer 540 contacts the surface of the surface film 1212, it is suitable for scenarios where the width of the circuit board 510 is narrow and there is not enough space for UF glue to be applied, thereby sealing the gap 600.

[0121] In some embodiments, see Figure 16 The hydrophobic layer 540, projected onto the circuit board 510, is a ring structure. The hydrophobic layer 540 surrounds the device body 521, and a portion of the hydrophobic layer 540 covers the sealing colloid 550. This reduces the manufacturing difficulty of the hydrophobic layer 540 and improves its manufacturing efficiency.

[0122] Figure 18 In order to be in Figure 15 The diagram shows the route for coating hydrophobic material and applying UF adhesive on a narrow circuit board.

[0123] like Figure 18 As shown, during the fabrication of the sealing structure, sealant (e.g., UF adhesive) is first applied to the solder joint 530 using a dispensing process to form a sealant 550 covering the solder joint 530. Then, a certain amount of waterproof material is applied to the periphery of the device body 521 at the junction with the circuit board 510 using coating processes such as dotting, spraying, and atomization deposition to form a hydrophobic layer 540 surrounding the device body 521.

[0124] Of course, in other embodiments, the hydrophobic layer 540 may not be a ring structure. In this case, the hydrophobic layer 540 may include multiple hydrophobic segments, which are arranged at intervals along the circumference of the circuit board 510, and a hydrophobic segment is provided between two adjacent solder joints 530.

[0125] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0126] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

Claims

1. A circuit board assembly (500), characterized in that, include: Circuit board (510); An electronic device (520) includes a device body (521) and connection pins, the connection pins being soldered to a circuit board (510) to form solder joints (530), and a gap (600) between the device body (521) and the circuit board (510) along the thickness direction of the circuit board (510). A sealing structure surrounds the electronic device (520) and is connected to the electronic device (520) and the circuit board (510) respectively, the sealing structure seals the gap (600) and covers the solder joint (530), the sealing structure includes a hydrophobic layer (540) that seals at least a portion of the gap (600).

2. The circuit board assembly (500) according to claim 1, characterized in that, The hydrophobic layer (540) has a ring-shaped projection on the circuit board (510). The hydrophobic layer (540) surrounds the device body (521). The first part of the hydrophobic layer (540) blocks the gap (600), and the second part of the hydrophobic layer (540) covers the solder joint (530).

3. The circuit board assembly (500) according to claim 1, characterized in that, The sealing structure further includes: A sealing colloid (550) is connected to the device body (521), the circuit board (510) and the hydrophobic layer (540) respectively, and the sealing colloid (550) covers the solder joint (530).

4. The circuit board assembly (500) according to claim 3, characterized in that, The hydrophobic layer (540) seals the gap (600).

5. The circuit board assembly (500) according to claim 3, characterized in that, The first portion of the sealant (550) covers the solder joint (530), the second portion of the sealant (550) covers a portion of the gap (600), and the hydrophobic layer (540) seals another portion of the gap (600).

6. The circuit board assembly (500) according to any one of claims 3 to 5, characterized in that, The hydrophobic layer (540) has a ring-shaped projection on the circuit board (510), the hydrophobic layer (540) surrounds the device body (521), and a portion of the hydrophobic layer (540) covers the sealant (550).

7. The circuit board assembly (500) according to any one of claims 1 to 6, characterized in that, The thickness of the hydrophobic layer (540) is greater than or equal to 1 nm and less than or equal to 20 μm.

8. The circuit board assembly (500) according to any one of claims 1 to 7, characterized in that, The hydrophobic layer (540) is made of silicon-based polymer hydrophobic material or fluorine-based hydrophobic material.

9. The circuit board assembly (500) according to claim 8, characterized in that, The hydrophobic layer (540) is made of dimethylsiloxane, vinylsiloxane, methoxy-nonafluorobutane, perfluoroalkyl acrylate or fluorohydroether.

10. The circuit board assembly (500) according to any one of claims 1 to 9, characterized in that, The hydrophobic layer (540) is formed by curing a hydrophobic material with a solid content of less than or equal to 30 wt%.

11. The circuit board assembly (500) according to any one of claims 1 to 10, characterized in that, Along the width direction of the circuit board (510), the distance between at least one of the opposite sides of the device body (521) along the width direction of the circuit board (510) and the edge of the circuit board (510) is less than 0.5 mm.

12. The circuit board assembly (500) according to any one of claims 1 to 11, characterized in that, The width of the circuit board (510) is less than or equal to 4 mm.

13. The circuit board assembly (500) according to any one of claims 1 to 12, characterized in that, The circuit board (510) is a flexible circuit board.

14. The circuit board assembly (500) according to any one of claims 1 to 13, characterized in that, The electronic device (520) is a switch (121), a resistor, a capacitor, or a connector.

15. The circuit board assembly (500) according to claim 14, characterized in that, The electronic device (520) is a switching device (121), and the device body (521) includes a mounting base (1211), a surface film (1212), a movable contact (1213), a fixed contact (1214), and a push plate (1215); The mounting base (1211) and the circuit board (510) form the gap (600). The mounting base (1211) and the surface film (1212) enclose an installation space. The fixed contact (1214), the movable contact (1213), and the push plate (1215) are all located inside the installation space. Along the thickness direction of the circuit board (510), the push plate (1215) is located between the surface film (1212) and the movable contact (1213). The push plate (1215) and the fixed contact (1214) are located on opposite sides of the movable contact (1213). The fixed contact (1214) is fixedly connected to the mounting base (1211) and electrically connected to the circuit board (510). One end of the connection pin is located outside the mounting space, and the other end of the connection pin is electrically connected to the fixed contact (1214).

16. An electronic device, characterized in that, Includes the circuit board assembly (500) as described in any one of claims 1 to 15.

17. The electronic device according to claim 16, characterized in that, The electronic device includes: The middle frame (200) is provided with button holes (210); The button assembly (100) includes a button (110) and the circuit board assembly (500). The electronic device (520) of the circuit board assembly (500) is a switch device (121). One end of the button (110) is exposed to the outside of the electronic device through the button hole (210), and the other end of the button (110) is used to connect with the electronic device (520) to enable the switch device (121) to conduct.

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