Method for manufacturing a circuit board assembly, circuit board assembly, and electronic device

Abstract

This application discloses a method for manufacturing a circuit board assembly, a circuit board assembly, and an electronic device. The method for manufacturing the circuit board assembly includes: placing a component to be assembled on a first mold, with the circuit board of the component located between the first mold and a dome switch; the first mold supporting the component; fastening a second mold to the side of the circuit board facing away from the first mold, forming a mounting cavity between the second mold and the circuit board, with the dome switch located within the mounting cavity; the second mold fixing the component to be assembled and engaging with the circuit board to form the mounting cavity; injecting a molding compound into the mounting cavity and curing the molding compound to form a cured body; laser-cutting the cured body to form a molding layer and a sealing portion; or applying adhesive between the cured body and the dome switch, and laser-cutting the cured body and the adhesive to form a molding layer and a sealing portion.

Description

Technical Field

[0001] This application belongs to the field of electronic equipment technology, specifically relating to a method for manufacturing a circuit board assembly, the circuit board assembly, and an electronic device. Background Technology

[0002] The electronic device includes side buttons and a circuit board assembly. The circuit board assembly includes a circuit board and a dome switch. The dome switch is located between the side buttons and the circuit board. The width of the circuit board assembly directly affects the thickness of the entire device.

[0003] In related technologies, to ensure the waterproof performance of the circuit board assembly, adhesive is applied to one side of the circuit board assembly along its width during manufacturing to form a wrapping adhesive around the metal dome. This wrapping adhesive seals the connection between the circuit board and the metal dome. Along the width of the circuit board assembly, the sum of the dimensions of the metal dome and the wrapping adhesive surrounding it is a critical dimension affecting the overall thickness. However, to ensure a high sealing yield of the circuit board assembly, sufficient dispensing distance must be allowed for the wrapping adhesive (the distance between the adhesive-applied side of the metal dome and the outer edge of the circuit board along the width of the circuit board assembly). Since the minimum dispensing distance is fixed, the width of the circuit board assembly cannot be further reduced, thus preventing further reduction in the overall thickness. Summary of the Invention

[0004] This application aims to provide a method for manufacturing a circuit board assembly, a circuit board assembly, and an electronic device, which can solve the problem in the related art where the width of the circuit board assembly cannot be reduced due to unreasonable manufacturing methods.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application propose a method for manufacturing a circuit board assembly. The method includes: placing a component to be assembled on a first mold, the component including a circuit board and a dome switch, the circuit board being located between the first mold and the dome switch, the first mold supporting the component to be assembled; fastening a second mold to the side of the circuit board away from the first mold, the second mold and the circuit board forming an installation cavity, the dome switch being located within the installation cavity, the second mold fixing the component to be assembled and cooperating with the circuit board to form the installation cavity; injecting a molding compound into the installation cavity and curing the molding compound to form a cured body; laser-cutting the cured body to form a molding layer and a sealing portion; or applying adhesive between the cured body and the dome switch, laser-cutting the cured body and the adhesive to form a molding layer and a sealing portion; wherein the sealing portion is located between the molding layer and the dome switch, both the molding layer and the sealing portion surrounding the dome switch, the sealing portion sealing the connection between the circuit board, the molding layer and the dome switch, and a portion of the dome switch protruding from the sealing portion on the side facing away from the circuit board.

[0007] Secondly, embodiments of this application provide a circuit board assembly, which is manufactured by the method for manufacturing a circuit board assembly in the first aspect. The circuit board assembly includes: a circuit board; a dome switch, which is stacked on one side of the circuit board and electrically connected to the circuit board; a molding compound, which is located on the same side of the circuit board and connected to the circuit board; and a sealing portion, which is located between the molding compound and the dome switch. Both the molding compound and the sealing portion are arranged around the dome switch, and the sealing portion is used to seal the connection between the circuit board, the molding compound, and the dome switch; wherein a portion of the dome switch protrudes from the sealing portion and faces away from the end face of the circuit board.

[0008] Thirdly, embodiments of this application provide an electronic device, including: a frame with an opening on its side; a button located at the opening and movably connected to the frame; and a circuit board assembly as described in the second aspect, the circuit board assembly being disposed in the frame, with the button and the portion of the dome switch protruding from the sealing portion being disposed opposite each other.

[0009] In the embodiments of this application, the assembly to be assembled (including a circuit board and a dome switch) is placed on a first mold, with the circuit board positioned between the first mold and the dome switch. Then, a second mold is fastened onto the side of the circuit board facing away from the first mold, forming a mounting cavity between the second mold and the circuit board, within which the dome switch of the assembly to be assembled is located. It is understood that the first mold supports the assembly to be assembled, and the second mold fixes the assembly to be assembled and mates with the circuit board to form the mounting cavity. Both the first and second molds are molds used to prepare the circuit board assembly; however, neither the first nor the second mold is a component of the circuit board assembly.

[0010] Molding compound is injected into the mounting cavity and cured to form a cured body. A second mold is opened, and the cured body is laser-cut to form a molding layer and a sealing portion. Alternatively, the second mold is opened, adhesive is applied between the cured body and the dome switch, and the cured body and adhesive are laser-cut to form a molding layer and a sealing portion. The molding layer is attached to the circuit board and surrounds the dome switch. The sealing portion is located between the molding layer and the dome switch and surrounds the dome switch. The sealing portion connects the circuit board, the molding layer, and the dome switch, sealing the connection points to provide the circuit board assembly with waterproof and corrosion-resistant properties.

[0011] In this application, since the molding compound is formed by molding and its shape is trimmed by laser cutting, the dimension of the molding compound in the width direction of the circuit board assembly is not limited by the dispensing distance limitation in related technologies. The dimension of the molding compound in the width direction of the circuit board assembly can be reduced according to usage requirements. This application changes the manufacturing method of the circuit board assembly in related technologies. Along the width direction of the circuit board assembly, the sum of the dimensions of the dome switch, the sealing portion, and the laser-trimmed molding compound is smaller than the sum of the dimensions of the dome switch and the encapsulating adhesive in related technologies. This eliminates the dispensing distance limitation of the sealing structure used to seal the connection between the dome switch and the circuit board, thereby facilitating a reduction in the width of the circuit board assembly and contributing to the overall thinning of electronic devices.

[0012] Understandably, the sealing element is located between the molding compound and the dome switch, and the sum of the dimensions of the sealing element, molding compound, and dome switch affects the minimum width of the circuit board assembly. The molding compound is formed through a molding process, and its outer contour is formed by laser cutting. This means that the sealing and waterproofing structure of the circuit board assembly is not limited by the dispensing distance. The width of the circuit board assembly is determined by the dome switch, the sealing element, and the laser-cut molding compound, rather than by the dome switch and the dispensing distance.

[0013] It is understandable that a portion of the dome switch protrudes from the sealing part and is away from the side end face of the circuit board. That is, the dome switch is not completely covered by the sealing part. The portion of the dome switch protruding from the sealing part is used to cooperate with the buttons of the electronic device. When the button is triggered, it can squeeze the portion of the dome switch protruding from the sealing part to achieve functions such as adjusting the volume and turning on the device.

[0014] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0015] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0016] Figure 1 This is a flowchart of a method for manufacturing a circuit board assembly according to an embodiment of this application;

[0017] Figure 2 This is a partial structural diagram of an electronic device according to an embodiment of this application;

[0018] Figure 3 This is a schematic diagram of the first part of the assembly to be assembled according to an embodiment of this application;

[0019] Figure 4 This is a schematic diagram of the second part of the assembly to be assembled according to an embodiment of this application;

[0020] Figure 5 This is a schematic diagram of the third part of the assembly to be assembled according to an embodiment of this application;

[0021] Figure 6 This is a schematic diagram of the fourth part of the assembly to be assembled according to an embodiment of this application;

[0022] Figure 7 This is a schematic diagram of the fifth part of the assembly to be assembled according to an embodiment of this application;

[0023] Figure 8 This is a schematic diagram of the sixth part of the assembly to be assembled according to an embodiment of this application;

[0024] Figure 9 This is a schematic diagram of the structure of the assembly to be assembled according to an embodiment of this application;

[0025] Figure 10 This is an exploded view of the first mold, the second mold, and the assembly to be assembled according to the first embodiment of this application;

[0026] Figure 11 This is a schematic diagram of the structure of the first mold, the second mold, the injection rod, and the molding compound according to the first embodiment of this application;

[0027] Figure 12 This is a partial structural schematic diagram of the first mold, the second mold, and the assembly to be assembled according to the first embodiment of this application;

[0028] Figure 13 This is a schematic diagram of the first part of the circuit board assembly according to the first embodiment of this application;

[0029] Figure 14 This is a schematic diagram of the second part of the circuit board assembly according to the first embodiment of this application;

[0030] Figure 15 This is a partial structural schematic diagram of the first mold, the second mold, the assembly to be assembled, the dome switch, and the electronic components according to the second embodiment of this application;

[0031] Figure 16 This is a partial structural schematic diagram of the second mold and the hot plate according to the second embodiment of this application;

[0032] Figure 17 This is a partial structural schematic diagram of a circuit board assembly according to a second embodiment of this application;

[0033] Figure 18 This is a schematic diagram of a panel structure of multiple circuit boards according to one embodiment of this application.

[0034] Figure label:

[0035] 1. Electronic device; 10. Circuit board assembly; 100. Circuit board; 110. First area; 120. Second area; 130. Third area; 141. Metal layer; 142. Wiring layer; 150. Insulating dielectric layer; 150a. First insulating dielectric layer; 150b. Second insulating dielectric layer; 150c. Third insulating dielectric layer; 160. Conductive hole; 170. First adhesive layer; 180. Second adhesive layer; 190. Assembly to be assembled; 200. Dome switch; 300. Molding layer; 400. Sealing part; 400a. Molding part; 400b. Encapsulation part; 500. Reinforcing plate; 600. Electronic component; 70. Frame; 700. Opening; 81. Button; 82. Battery cover; 83. Screen; 84. Motherboard; 91. First mold; 92. Second mold; 93. Mounting cavity; 931. First chamber; 932. Second chamber; 94. Injection rod; 95. Molding material; 96. Molding area. Detailed Implementation

[0036] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0037] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0038] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] The following is combined with Figures 1 to 18 This application describes a method for manufacturing a circuit board assembly, a circuit board assembly, and an electronic device according to embodiments of the present application.

[0040] like Figure 1 As shown, some embodiments of this application provide a method for manufacturing a circuit board assembly. Figure 1 A flowchart illustrating a method for fabricating a circuit board assembly according to an embodiment of this application is shown. Figure 1 As shown, the method for manufacturing the circuit board assembly includes:

[0041] Step 101: Place the assembly to be assembled on the first mold. The assembly to be assembled includes a circuit board and a dome switch. The circuit board is located between the first mold and the dome switch. The first mold is used to support the assembly to be assembled.

[0042] Step 102: The second mold is fastened to the side of the circuit board away from the first mold, and the second mold and the circuit board enclose an installation cavity. The dome switch is located in the installation cavity. The second mold is used to fix the assembly to be assembled and cooperates with the circuit board to enclose the installation cavity.

[0043] Step 103: Inject molding compound into the mounting cavity and cure the molding compound to form a cured body, then proceed to step 104 or step 105;

[0044] Step 104: Laser cutting of the cured body to form a molding layer and a sealing layer;

[0045] Step 105: Apply adhesive between the cured body and the dome switch, and laser cut the cured body and the adhesive to form a molding layer and a sealing part.

[0046] In the embodiments of this application, the assembly to be assembled (including a circuit board and a dome switch) is placed on a first mold, with the circuit board positioned between the first mold and the dome switch. Then, a second mold is fastened onto the side of the circuit board facing away from the first mold, forming a mounting cavity between the second mold and the circuit board, within which the dome switch of the assembly to be assembled is located. It is understood that the first mold supports the assembly to be assembled, and the second mold fixes the assembly to be assembled and mates with the circuit board to form the mounting cavity. Both the first and second molds are molds used to prepare the circuit board assembly; however, neither the first nor the second mold is a component of the circuit board assembly.

[0047] Molding compound is injected into the mounting cavity and cured to form a cured body. A second mold is opened, and the cured body is laser-cut to form a molding layer and a sealing portion. Alternatively, the second mold is opened, adhesive is applied between the cured body and the dome switch, and the cured body and adhesive are laser-cut to form a molding layer and a sealing portion. The molding layer is attached to the circuit board and surrounds the dome switch. The sealing portion is located between the molding layer and the dome switch and surrounds the dome switch. The sealing portion connects the circuit board, the molding layer, and the dome switch, sealing the connection points to provide the circuit board assembly with waterproof and corrosion-resistant properties.

[0048] In this application, since the molding compound is formed by molding and its shape is trimmed by laser cutting, the dimension of the molding compound in the width direction of the circuit board assembly is not limited by the dispensing distance limitation in related technologies. The dimension of the molding compound in the width direction of the circuit board assembly can be reduced according to usage requirements. This application changes the manufacturing method of the circuit board assembly in related technologies. Along the width direction of the circuit board assembly, the sum of the dimensions of the dome switch, the sealing portion, and the laser-trimmed molding compound is smaller than the sum of the dimensions of the dome switch and the encapsulating adhesive in related technologies. This eliminates the dispensing distance limitation of the sealing structure used to seal the connection between the dome switch and the circuit board, thereby facilitating a reduction in the width of the circuit board assembly and contributing to the overall thinning of electronic devices.

[0049] Understandably, the sealing element is located between the molding compound and the dome switch, and the sum of the dimensions of the sealing element, molding compound, and dome switch affects the minimum width of the circuit board assembly. The molding compound is formed through a molding process, and its outer contour is formed by laser cutting. This means that the sealing and waterproofing structure of the circuit board assembly is not limited by the dispensing distance. The width of the circuit board assembly is determined by the dome switch, the sealing element, and the laser-cut molding compound, rather than by the dome switch and the dispensing distance.

[0050] It is understandable that a portion of the dome switch protrudes from the sealing part and is away from the side end face of the circuit board. That is, the dome switch is not completely covered by the sealing part. The portion of the dome switch protruding from the sealing part is used to cooperate with the buttons of the electronic device. When the button is triggered, it can squeeze the portion of the dome switch protruding from the sealing part to achieve functions such as adjusting the volume and turning on the device.

[0051] Molding material is extruded into the mounting cavity using an injection molding rod, and air is expelled from the cavity through the vent of at least one of the first and second molds. The molding material is then cured to form a solidified body. The second mold is then opened, and the solidified body is laser-cut to form the molding layer and the sealing element. The molding layer and the sealing element are made of the same material and are an integral structure formed by the molding process. This ensures the dimensional fit between the sealing element, the dome switch, and the circuit board, guarantees reliable sealing, simplifies the processing steps of the circuit board assembly, simplifies manufacturing, and results in a high product yield.

[0052] Alternatively, molding compound can be extruded into the mounting cavity using an injection molding rod, and air is expelled from the cavity through the vents of at least one of the first and second molds. The molding compound is then cured to form a solidified body. The second mold is then opened, and adhesive is applied to the gap between the dome and the solidified body using a dispensing process. Finally, the solidified body and the adhesive are laser-cut to form the molding layer and the sealing portion. It is understood that the solidified body and the dome form a groove-shaped structure to accommodate the adhesive, which serves to limit the adhesive and allow it to effectively fill the gap between the circuit board, the dome, and the molding layer, ensuring a sealing effect.

[0053] Understandably, when applying adhesive between the cured body and the dome switch, the dispensing distance is limited to the inside of the cured body, without increasing the width of the circuit board assembly.

[0054] Understandably, the seal formed by laser-cut adhesive has the ability to deform elastically, which can provide a cushioning effect when the dome is pressed, avoiding rigid contact between the plastic seal and the dome, thus reducing the risk of fatigue failure of the dome and improving the user's pressing feel.

[0055] Understandably, the sealing part is formed by dispensing adhesive, which can effectively fill the gap between the molding layer, the circuit board and the dome switch, thus improving the waterproof rating of the circuit board assembly.

[0056] In some embodiments, based on the application of adhesive between the cured body and the dome switch, the second mold has a baffle that separates the mounting cavity into a first chamber and a second chamber, the dome switch being located in the first chamber and having a gap between the dome switch and the cavity wall of the first chamber; the step of forming the cured body specifically includes: injecting molding compound into the second chamber and curing the molding compound.

[0057] In this embodiment, based on the application of encapsulating adhesive between the cured body and the dome switch, the second mold has a baffle. When the second mold is fastened to the side of the circuit board facing away from the first mold, the baffle separates the mounting cavity into a first chamber and a second chamber, with the dome switch located in the first chamber. Molding material is extruded into the second chamber via an injection molding rod, and air is expelled from the second chamber through the vent of at least one of the first and second molds. The molding material is then cured to form a cured body. The second mold is then opened, leaving a gap between the cured body and the dome switch. Encapsulating adhesive is applied to the gap between the dome switch and the cured body using a dispensing process. Finally, the cured body and the encapsulating adhesive are laser-cut to form a molding layer and a sealing portion.

[0058] In some embodiments, when the curing body is laser-cut to form a molding layer and a sealing portion, the second mold snaps onto the side of the circuit board away from the first mold and presses the dome.

[0059] In this embodiment, the second mold snaps onto the side of the circuit board away from the first mold and squeezes the dome switch. In this way, when the molding compound is squeezed into the mounting cavity by the injection rod, the molding compound will not cover the part of the dome switch squeezed by the second mold. This can meet the usage requirement that part of the dome switch protrudes from the sealing part and is away from the end face of the circuit board, and provide structural support for the effective cooperation between the dome switch and the button of the electronic device.

[0060] Understandably, the second mold snaps onto the side of the circuit board away from the first mold and squeezes the hot plate, causing the hot plate to deform. After the second mold is opened, at least part of the hot plate that was squeezed will recover its deformation.

[0061] In some embodiments, the assembly to be assembled further includes electronic components located within the mounting cavity, and the cured body encapsulates the electronic components.

[0062] In this embodiment, the assembly to be assembled also includes electronic components, which are located within the mounting cavity and encapsulated by the cured body. That is, the electronic components are embedded within the molding compound, which separates the electronic components from water, dirt, and other contaminants in the external environment.

[0063] In some embodiments, the circuit board includes a first region. The step of laser cutting the cured body to form a molding compound specifically includes: using the outer edge of the first region as a reference edge, laser cutting the cured body so that the outer contour of the molding compound overlaps with the outer edge of the first region; wherein, along the first direction, the width of the portion of the circuit board located between the dome switch and the outer edge of the first region is greater than or equal to 0.15 mm.

[0064] In this embodiment, the circuit board includes a first region. The outer edge of the first region is used as a reference edge. The cured body is laser-cut so that the outer contour of the molding compound overlaps with the outer edge of the first region. The first region connects the molding compound, the sealing part, and the dome switch. That is, a part of the circuit board is used to connect with the molding compound, the sealing part, and the dome switch, rather than the entire circuit board being covered by the molding compound.

[0065] It is understandable that the outer edge of the cured molding compound is located outside the outer edge of the first area of ​​the circuit board. After opening the second mold, the cured molding compound is cut by laser cutting to form a molding layer. The outer contour of the molding layer is also overlapped with the outer edge of the first area by laser cutting. That is, not only can the size of the molding layer in the width direction of the circuit board assembly be reduced according to the usage requirements, but the positional relationship of the molding layer, the sealing part and the dome switch can also be guaranteed, and the setting position and molding size of the sealing part can be guaranteed.

[0066] Understandably, along the first direction, the sum of the dimensions of the sealing part, the plastic sealant, and the dome switch is the key dimension affecting the overall thickness of the machine.

[0067] Along the first direction, the width of the portion of the circuit board assembly located between the dome switch and the outer edge of the first region is greater than or equal to 0.15 mm, that is, the minimum width of the portion of the circuit board assembly located between the dome switch and the outer edge of the first region is defined as 0.15 mm. In related technologies, the minimum dispensing distance along the first direction is 0.7 mm. Taking a conventional dome switch (the width of the dome switch along the first direction is 1.9 mm) as an example, the minimum width of the circuit board assembly in the first direction of this application is 2.2 mm, while the minimum width of the circuit board assembly in the first direction of related technologies is 3.3 mm. The width of the circuit board assembly in the first direction of this application is reduced by 30% compared to the circuit board assembly in the related technologies.

[0068] In addition, along the first direction, the width of the portion of the circuit board assembly located between the dome and the outer edge of the first region is greater than or equal to 0.15 mm, which can ensure a safety margin in the laser cutting process, avoid damage to the dome, and also avoid weakening the sealing performance of the sealing part.

[0069] It is understandable that the outer contour of the molding compound overlaps with the outer edge of the first region. The outer contour of the molding compound is formed by laser cutting, and the molding compound will not extend beyond the outer edge of the circuit board.

[0070] like Figure 9 , Figure 13 , Figure 14 and Figure 17 As shown, some embodiments of this application provide a circuit board assembly 10, which is manufactured by the method of manufacturing the circuit board assembly of any of the above embodiments. The circuit board assembly 10 includes: a circuit board 100; a dome switch 200, which is stacked on one side of the circuit board 100 and electrically connected to the circuit board 100; a molding compound 300, which is located on the same side of the circuit board 100 and connected to the circuit board 100; and a sealing portion 400, which is located between the molding compound 300 and the dome switch 200. Both the molding compound 300 and the sealing portion 400 are disposed around the dome switch 200, and the sealing portion 400 is used to seal the connection between the circuit board 100, the molding compound 300 and the dome switch 200; wherein a portion of the dome switch 200 protrudes from the sealing portion 400 and faces away from the side end face of the circuit board 100.

[0071] In this embodiment, the circuit board assembly 10 includes a circuit board 100, a dome switch 200, a molding compound 300, and a sealing portion 400.

[0072] The dome switch 200, molding compound 300, and sealing portion 400 are located on the same side of the circuit board 100. The dome switch 200 is electrically connected to the circuit board 100. The assembly to be assembled 190 includes the dome switch 200 and the circuit board 100. After the assembly to be assembled 190 is placed on the first mold 91, the second mold 92 is fastened onto the side of the circuit board 100 opposite to the first mold 91, forming an mounting cavity 93 between the second mold 92 and the circuit board 100. Molding compound 95 is injected into the mounting cavity 93 and cured to form a cured body. The second mold 92 is opened, and the cured body is laser-cut to form the molding compound 300 and the sealing portion 400. Alternatively, the second mold 92 is opened, adhesive is applied between the cured body and the dome switch 200, and the cured body and adhesive are laser-cut to form the molding compound 300 and the sealing portion 400. The molding compound 300 is connected to the circuit board 100 and surrounds the dome switch 200. A sealing portion 400 is located between the molding compound 300 and the dome switch 200, and surrounds the dome switch 200. The sealing portion 400 connects the circuit board 100, the molding compound 300, and the dome switch 200, and can seal the connection points of the circuit board 100, the molding compound 300, and the dome switch 200, so that the circuit board assembly 10 has waterproof and corrosion-resistant functions.

[0073] In this application, since the molding compound 300 is formed by mold and its shape is trimmed by laser cutting, the dimension of the molding compound 300 in the width direction of the circuit board assembly 10 is not limited by the dispensing distance limitation in the related technology. The dimension of the molding compound 300 in the width direction of the circuit board assembly 10 can be reduced according to the usage requirements. This application changes the sealing and waterproofing structure of the circuit board assembly in the related technology. Along the width direction of the circuit board assembly 10, the sum of the dimensions of the dome 200, the sealing part 400, and the laser-trimmed molding compound 300 is smaller than the sum of the dimensions of the dome 200 and the encapsulating adhesive in the related technology. This can eliminate the dispensing distance limitation of the sealing structure used to seal the connection between the dome 200 and the circuit board 100, thereby helping to reduce the width of the circuit board assembly 10 and the overall thinning of the electronic device 1.

[0074] It is understandable that, such as Figure 14 and Figure 17 As shown, the first direction is the width direction of the circuit board assembly 10.

[0075] It is understandable that the sealing part 400 is located between the molding layer 300 and the dome switch 200. The sum of the dimensions of the sealing part 400, the molding layer 300, and the dome switch 200 affects the minimum width of the circuit board assembly 10. The molding layer 300 is formed by molding, and the outer contour of the molding layer 300 is formed by laser cutting. That is, the sealing and waterproof structure of the circuit board assembly 10 is not limited by the dispensing distance. The width of the circuit board assembly 10 is determined by the dome switch 200, the sealing part 400, and the molding layer 300 after laser cutting, and is no longer determined by the dome switch 200 and the dispensing distance.

[0076] It is understandable that a portion of the dome switch 200 protrudes from the sealing portion 400 and is away from the side end face of the circuit board 100. That is, the dome switch 200 is not completely covered by the sealing portion 400. The portion of the dome switch 200 protruding from the sealing portion 400 is used to cooperate with the button 81 of the electronic device 1. When the button 81 is triggered, it can squeeze the portion of the dome switch 200 protruding from the sealing portion 400 to realize functions such as adjusting volume and turning on.

[0077] In some embodiments, such as Figure 14 and Figure 17 As shown, the sealing part 400 includes a molding part 400a, and the molding part 400a and the molding layer 300 are an integral structure; or the sealing part 400 includes an encapsulating adhesive part 400b.

[0078] In this embodiment, the sealing part 400 includes a molding part 400a, and the molding part 400a and the molding layer 300 are an integral structure. That is, the molding material 95 is extruded into the mounting cavity 93 by the injection rod 94, and the air in the mounting cavity 93 is discharged through the vent of at least one of the first mold 91 and the second mold 92, and then the molding material 95 is cured to form a cured body. Then the second mold 92 is opened, and the cured body is laser-cut to form the molding layer 300 and the sealing part 400. The molding layer 300 and the sealing part 400 are made of the same material, and the molding layer 300 and the sealing part 400 are an integral structure formed by the molding process, which can ensure the matching dimensions of the sealing part 400, the dome switch 200 and the circuit board 100, ensure the sealing reliability, simplify the processing steps of the circuit board assembly 10, simplify manufacturing, and increase the product yield.

[0079] In this embodiment, the sealing portion 400 includes an encapsulating adhesive portion 400b. The second mold 92 has a baffle. When the second mold 92 is fastened to the side of the circuit board 100 facing away from the first mold 91, the baffle separates the mounting cavity 93 into a first chamber 931 and a second chamber 932, with the dome switch 200 located in the first chamber 931. A molding compound 95 is extruded into the second chamber 932 via an injection rod 94, and air in the second chamber 932 is expelled through the vent of at least one of the first mold 91 and the second mold 92. The molding compound 95 is then cured to form a cured body. The second mold 92 is then opened, and encapsulating adhesive is applied to the gap between the dome switch 200 and the cured body using a dispensing process. Finally, the cured body and the encapsulating adhesive are laser-cut to form the molding layer 300 and the sealing portion 400. Understandably, the cured body and the dome 200 form a groove-shaped structure to accommodate the encapsulating adhesive, which serves to limit the encapsulating adhesive and allows it to effectively fill the gap between the circuit board 100, the dome 200, and the molding compound 300, ensuring a sealing effect.

[0080] Understandably, the dispensing distance of the encapsulating adhesive portion 400b is limited to the inside of the molding compound 300 without increasing the width of the circuit board assembly 10.

[0081] Understandably, the encapsulating adhesive portion 400b has the ability to deform elastically, which can provide a cushioning effect when the dome switch 200 is pressed, avoiding rigid contact between the plastic sealant layer 300 and the dome switch 200. This helps reduce the risk of fatigue failure of the dome switch 200 and also improves the user's pressing feel.

[0082] It is understandable that the encapsulation adhesive portion 400b is formed by dispensing adhesive. The encapsulation adhesive portion 400b can effectively fill the gap between the molding layer 300, the circuit board 100 and the dome switch 200, which is beneficial to improving the waterproof rating of the circuit board assembly 10.

[0083] In some embodiments, there are multiple dome switches 200 and multiple sealing portions 400, with multiple dome switches 200 located on the same side of the circuit board 100, a molding compound 300 surrounding each dome switch 200, and each sealing portion 400 cooperating with one dome switch 200.

[0084] In this embodiment, there are multiple dome switches 200 and multiple sealing portions 400. The number of sealing portions 400 and dome switches 200 are equal, and the multiple sealing portions 400 cooperate with the multiple dome switches 200 one by one. Each dome switch 200 is equipped with a sealing portion 400, which can seal the connection between the dome switch 200, the circuit board 100 and the molding compound 300. The molding compound 300 is disposed around each dome switch 200.

[0085] Multiple dome switches 200 are located on the same side of the circuit board 100. The circuit board assembly 10 can integrate the functions of multiple buttons 81. Each dome switch 200 is equipped with a sealing part 400, which will not interfere with each other and can ensure the sealing reliability of each dome switch 200.

[0086] In some embodiments, such as Figure 8 As shown, the circuit board 100 includes a first region 110, which connects the molding compound 300, the sealing portion 400, and the dome switch 200. The outer contour of the molding compound 300 is formed by laser cutting, and the outer contour of the molding compound 300 overlaps with the outer edge of the first region 110. Along the first direction, the width of the portion of the circuit board 100 located between the dome switch 200 and the outer edge of the first region 110 is greater than or equal to 0.15 mm.

[0087] In this embodiment, the circuit board 100 includes a first region 110, which connects the molding compound 300, the sealing portion 400 and the dome switch 200. That is, a portion of the circuit board 100 is used to connect with the molding compound 300, the sealing portion 400 and the dome switch 200, rather than the entire circuit board 100 being covered by the molding compound 300.

[0088] It is understandable that the outer edge of the cured molding compound 95 is located outside the outer edge of the first region 110 of the circuit board 100. After the second mold 92 is opened, the cured molding compound 95 is cut by laser cutting to form the molding layer 300, and the outer contour of the molding layer 300 overlaps with the outer edge of the first region 110. That is, not only can the size of the molding layer 300 in the width direction of the circuit board assembly 10 be reduced according to the usage requirements, but the positional relationship of the molding layer 300, the sealing part 400 and the dome switch 200 can also be guaranteed, and the setting position and molding size of the sealing part 400 can be guaranteed.

[0089] It is understandable that, along the first direction, the sum of the dimensions of the sealing part 400, the plastic sealing layer 300, and the dome switch 200 is a key dimension affecting the overall thickness of the machine.

[0090] Along the first direction, the width of the portion of the circuit board assembly 10 located between the outer edges of the dome switch 200 and the first region 110 is greater than or equal to 0.15 mm. That is, the minimum width of the portion of the circuit board assembly 10 located between the outer edges of the dome switch 200 and the first region 110 is defined as 0.15 mm. In related technologies, the minimum dispensing distance along the first direction is 0.7 mm. Taking a conventional dome switch (with a width of 1.9 mm along the first direction) as an example, the minimum width of the circuit board assembly 10 in this application in the first direction is 2.2 mm, while the minimum width of the circuit board assembly in the first direction in related technologies is 3.3 mm. The width of the circuit board assembly 10 in this application in the first direction is reduced by 30% compared to the circuit board assembly in the related technologies.

[0091] In addition, along the first direction, the width of the portion of the circuit board assembly 10 located between the outer edge of the dome 200 and the first region 110 is greater than or equal to 0.15 mm, which can ensure a safety margin in the laser cutting process, avoid damage to the dome 200, and also avoid weakening the sealing performance of the sealing portion 400.

[0092] It is understandable that the outer contour of the molding compound 300 overlaps with the outer edge of the first region 110. The outer contour of the molding compound 300 is formed by laser cutting, and the molding compound 300 will not extend beyond the outer edge of the circuit board 100.

[0093] In some embodiments, such as Figure 8 As shown, the circuit board 100 is a flexible circuit board, and the circuit board assembly 10 further includes a reinforcing plate 500, which is connected to the side of the circuit board 100 away from the dome switch 200.

[0094] In this embodiment, the circuit board 100 is a flexible circuit board.

[0095] The circuit board assembly 10 also includes a reinforcing plate 500, which is connected to the side of the circuit board 100 away from the dome switch 200. The reinforcing plate 500 can provide support for the flexible circuit board, compensate for the rigidity of the flexible circuit board, ensure the flatness of the flexible circuit board and the overall strength of the circuit board assembly 10, prevent the circuit board assembly 10 from collapsing, ensure the matching dimensions of the dome switch 200 and the button 81 of the electronic device 1, and provide structural support for the sensitivity and effectiveness of the button 81 when it is triggered.

[0096] In some embodiments, the thickness of the reinforcing plate 500 is greater than or equal to 0.25 mm; and / or the reinforcing plate 500 includes a steel plate and / or an epoxy board.

[0097] In this embodiment, the thickness of the reinforcing plate 500 is greater than or equal to 0.25 mm to ensure the bending stiffness and support stability of the reinforcing plate 500, which can prevent excessive deformation of the part of the flexible circuit board and the dome switch 200 that are opposite to each other, and can ensure the effectiveness and reliability of the button 81 of the electronic device 1 being triggered.

[0098] For example, the outer edge of the reinforcing plate 500 overlaps with the outer edge of the circuit board 100, that is, the reinforcing plate 500 does not protrude from the outer edge of the circuit board 100, and does not increase the size of the circuit board assembly 10 in the first direction, which is beneficial to the overall thinning of the machine.

[0099] In this embodiment, the reinforcing plate 500 includes a steel plate and / or an epoxy board to ensure the bending stiffness of the reinforcing plate 500 and provide stable support for the circuit board 100.

[0100] When the reinforcing plate 500 includes a steel plate, the steel plate also serves to provide electromagnetic shielding.

[0101] When the reinforcing plate 500 includes an epoxy board, the epoxy board has the advantage of low cost.

[0102] For example, the reinforcing plate 500 is bonded to the circuit board 100.

[0103] In some embodiments, such as Figure 8 As shown, along the direction perpendicular to the dome switch 200 to the circuit board 100, the circuit board 100 further includes a second region 120 and a third region 130, with the second region 120 connected between the first region 110 and the third region 130; the circuit board 100 includes a plurality of metal layers 141 and a plurality of insulating dielectric layers 150, with the plurality of metal layers 141 stacked, and an insulating dielectric layer 150 disposed between any two adjacent metal layers 141; the number of metal layers 141 in either the first region 110 or the third region 130 is greater than the number of metal layers 141 in the second region 120, a portion of the reinforcing plate 500 is disposed opposite to the first region 110, and another portion of the reinforcing plate 500 is disposed opposite to the third region 130.

[0104] In this embodiment, the circuit board 100 is divided into regions such that, along the direction perpendicular to the dome switch 200 to the circuit board 100, the circuit board 100 is divided into a first region 110, a second region 120 and a third region 130, with the second region 120 connecting the first region 110 and the third region 130.

[0105] The circuit board 100 includes multiple metal layers 141 and multiple insulating dielectric layers 150. The multiple metal layers 141 are stacked, and an insulating dielectric layer 150 is disposed between any two adjacent metal layers 141.

[0106] The number of metal layers 141 in the first region 110 is greater than the number of metal layers 141 in the second region 120, and the number of metal layers 141 in the third region 130 is greater than the number of metal layers 141 in the second region 120. A portion of the reinforcing plate 500 is disposed opposite to the first region 110, and another portion of the reinforcing plate 500 is disposed opposite to the third region 130. The reinforcing plate 500 does not cover the second region 120 of the circuit board 100. This reduces the rigidity and thickness of the second region 120, which is the bending region of the circuit board 100. The third region 130 of the circuit board 100 is used for electrical connection with the motherboard 84 of the electronic device 1.

[0107] In some embodiments, such as Figure 8 As shown, the circuit board 100 is provided with conductive holes 160, and the circuit board 100 is provided with a wiring layer 142 on the side opposite to the dome 200. The dome 200 is electrically connected to the wiring layer 142 through the conductive holes 160.

[0108] In this embodiment, the circuit board 100 is provided with conductive vias 160, and a trace layer 142 is provided on the side of the circuit board 100 opposite to the dome switch 200. The dome switch 200 is electrically connected to the trace layer 142 through the conductive vias 160. That is, the dome switch 200 and the trace layer 142 are located on different sides of the circuit board 100, which can reduce the number of traces on the side of the circuit board 100 facing the dome switch 200, avoid the surface traces occupying the space of the circuit board 100 in the first direction, and help to further compress the size of the circuit board assembly 10 in the first direction.

[0109] If the dome switch 200 is directly connected to the wiring layer 142, the wiring of the wiring layer 142 will be arranged around the dome switch 200. Compared with arranging the wiring on the side of the circuit board 100 away from the dome switch 200, this will increase the size of the circuit board 100 in the first direction, and thus increase the width of the circuit board assembly 10, which is not conducive to reducing the thickness of the whole machine.

[0110] The dome switch 200 is electrically connected to the trace layer 142 through the conductive via 160. Although the dome switch 200 and the trace layer 142 are located on different sides of the circuit board 100, the dome switch 200 can still be electrically connected to the trace layer 142 through the conductive via 160, which can meet the requirements of signal transmission. In addition, the conductive via 160 transmits the signal to the side of the circuit board 100 away from the dome switch 200. A reference ground or power supply can be arranged on the side of the circuit board 100 away from the dome switch 200. This helps to improve the anti-interference capability and electrostatic discharge protection performance of the button 81 signal.

[0111] In some embodiments, such as Figure 13As shown, the circuit board assembly 10 further includes at least one electronic component 600, at least one electronic component 600 and the dome switch 200 are located on the same side of the circuit board 100, and the electronic component 600 is electrically connected to the circuit board 100, and the molding compound 300 covers each electronic component 600.

[0112] In this embodiment, the circuit board assembly 10 further includes at least one electronic component 600. The at least one electronic component 600, the dome switch 200, and the molding compound 300 are located on the same side of the circuit board 100. The electronic component 600 is electrically connected to the circuit board 100, and the molding compound 300 covers each electronic component 600. That is, the electronic component 600 is embedded within the molding compound 300, which separates the electronic component 600 from water, dirt, and other contaminants in the external environment.

[0113] like Figure 2 As shown, in some embodiments of this application, an electronic device 1 is provided. The electronic device 1 includes: a frame 70, with an opening 700 on the side of the frame 70; a button 81 located at the opening 700 and movably connected to the frame 70; and a circuit board assembly 10 of any of the above embodiments, the circuit board assembly 10 being disposed in the frame 70, with the button 81 and the portion of the dome switch 200 protruding from the sealing portion 400 being disposed opposite to each other.

[0114] It is understandable that when button 81 is triggered, button 81 can move relative to the frame 70.

[0115] The electronic device 1 provided in this application includes the circuit board assembly 10 of any of the above embodiments, and therefore has all the beneficial effects of the circuit board assembly 10, which will not be described in detail here.

[0116] For example, electronic device 1 may be a mobile terminal such as a mobile phone, a wearable device, a tablet computer, a laptop computer, a mobile computer, an augmented reality device (also known as an AR (Augmented Reality) device), a virtual reality device (also known as a VR (Virtual Reality) device), and a handheld game console, etc.

[0117] For example, this application reasonably sets the structure of the circuit board assembly 10 and achieves miniaturization of the circuit board assembly 10 through the molding process. Therefore, the width of the circuit board assembly 10 can be reduced and the overall reliability of the circuit board assembly 10 can be improved.

[0118] For example, the circuit board assembly 10 includes a circuit board 100, a dome switch 200, a molding compound 300, and a sealing portion 400. For instance, the circuit board 100 is a double-sided circuit board 100 with a thickness of 0.13 mm. Devices, such as the dome switch 200 and electronic components 600, are soldered to the top surface of the circuit board 100, and traces are routed to the bottom surface of the circuit board 100. The devices are electrically connected to the bottom surface traces through conductive vias 160, minimizing the space occupied in the width direction of the circuit board 100.

[0119] For example, the circuit board 100 is reinforced with steel. Specifically, the reinforcing plate 500 is connected to the side of the circuit board 100 away from the dome switch 200. The thickness of the reinforcing plate 500 is greater than or equal to 0.25mm. The reinforcing plate 500 can ensure the flatness of the circuit board 100 and improve the overall structural strength.

[0120] For example, such as Figure 8 As shown, the circuit board 100 is divided into a first region 110, a second region 120 and a third region 130, with the second region 120 being a single-layer wiring design. Figure 18 The diagram illustrates a panel structure of multiple circuit boards 100, with the areas requiring molding arranged in the same vertical column for easy encapsulation. The second region 120 is the bending area of ​​the circuit board 100, and the third region 130 is the contact gold surface area of ​​the circuit board 100. The second region 120 and the third region 130 need to be designed outside the molding area 96.

[0121] For example, Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The diagram illustrates the processing steps for the assembly component 190. For example... Figures 3 to 8 As shown, the first region 110 is the side button area, the second region 120 is the bending area, and the third region 130 is the contact gold surface area. Both the first region 110 and the third region 130 include two metal layers 141, allowing for double-sided or single-sided routing. The second region 120 has one metal layer 141 etched away for single-sided routing. The structure of the assembly 190 after drilling is detailed below. Figure 4 The structure of the assembly to be assembled after copper plating is detailed in [link to documentation]. Figure 5 The structure of the assembly 190 after the etching process is detailed in [link to image]. Figure 6 The structure of the assembly 190 after the protective film application and surface treatment processes is detailed in [link to documentation]. Figure 7 The structure of the assembly 190 after the reinforcement and bonding process is detailed in [link to documentation]. Figure 8 .

[0122] For example, Figure 9The structure of the assembly 190 before encapsulation is shown. Figure 15 The structure of the assembly 190 after encapsulation is shown. All electronic components 600 are embedded in the plastic encapsulation layer 300, and only a part of the dome switch 200 is exposed. The part of the dome switch 200 that protrudes from the sealing part 400 is used to cooperate with the button 81 of the electronic device 1.

[0123] For example, such as Figure 10 and Figure 11 As shown, the mold includes a first mold 91, a second mold 92, and an injection rod 94. The assembly to be assembled 190 is placed on the first mold 91. After the second mold 92 is pressed down, the second mold 92 snaps onto the side of the circuit board 100 away from the first mold 91 and squeezes the dome switch 200, causing the dome switch 200 to deform.

[0124] For example, such as Figure 11 and Figure 12 As shown, injection molding rod 94 extrudes epoxy molding compound into mounting cavity 93, and expels air from mounting cavity 93 through the vent of at least one of the first mold 91 and the second mold 92. After air is expelled, the epoxy molding compound is cured. Once fully cured, the second mold 92 is opened. After mold opening, the shape of the cured body is laser-cut to form the molding layer 300 and the sealing part 400. Figure 12 As shown, after mold closing, the dimension of the dome switch 200 in the second direction is A1, 0.36mm≤A1≤0.54mm. Figure 12 As shown, after mold closing, along the second direction, the distance between the portion of the cavity wall of the mounting cavity 93 opposite to the electronic component 600 and the assembly 190 is B1, 0.56mm≤B1≤0.84mm. Figure 12 As shown, after mold closing, along the third direction, the distance between the cavity wall of mounting cavity 93 and the dome switch 200 is C1, 0.15mm≤C1≤0.24mm. Figure 12 As shown, after mold closing, along the second direction, the distance between the portion of the second mold 92 located around the dome switch 200 and the circuit board 100 is D1, where 0.24mm ≤ D1 ≤ 0.36mm. Figure 13 As shown, along the second direction, the height of the molding compound 300 is E1, where 0.7mm ≤ E1 ≤ 0.8mm. Figure 13 As shown, along the second direction, the height of the sealing part 400 is E2, where 0.1mm ≤ E2 ≤ 0.3mm. (As...) Figure 13 As shown, along the second direction, the height of the assembly 190 is E3. The height of the assembly 190 includes the height h1 of the circuit board 100 and the height h2 of the reinforcing plate 500, where h1 = 0.13 mm, and 0.25 mm ≤ h2 ≤ 0.35 mm. Figure 14As shown, along the first direction, the distance from the side of the molding compound 300 away from the dome switch 200 to the dome switch 200 is E4, where 0.15mm ≤ E4 ≤ 0.2mm. For example, the values ​​of A1 include 0.38mm, 0.4mm, 0.42mm, 0.45mm, 0.5mm, 0.52mm, and 0.54mm, etc., and are not listed here. The values ​​of B1 include 0.58mm, 0.59mm, 0.6mm, 0.65mm, 0.68mm, 0.7mm, 0.72mm, 0.75mm, and 0.8mm, etc., and are not listed here. The values ​​of C1 include 0.16mm, 0.18mm, 0.2mm, 0.21mm, 0.22mm, and 0.23mm, etc., and are not listed here. Values ​​for D1 include 0.25mm, 0.28mm, 0.3mm, 0.32mm, 0.33mm, and 0.35mm, etc., and are not listed here. Values ​​for E1 include 0.71mm, 0.72mm, 0.73mm, 0.74mm, 0.75mm, 0.76mm, 0.77mm, 0.78mm, and 0.79mm, etc., and are not listed here. Values ​​for E2 include 0.12mm, 0.15mm, 0.16mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, and 0.28mm, etc., and are not listed here. Values ​​for h2 include 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, and 0.33mm, etc., and are not listed here. The values ​​for E4 include 0.16mm, 0.17mm, 0.18mm, and 0.19mm, etc., which will not be listed here.

[0125] like Figure 15 and Figure 16 As shown, after the mold is closed, the second mold 92 presses down to completely isolate and protect the dome switch 200. Specifically, after the mold is closed, the baffle of the second mold 92 separates the mounting cavity 93 into a first chamber 931 and a second chamber 932, with the dome switch 200 located in the first chamber 931. Figure 15 As shown, after mold closing, the height of the first chamber 931 in the second direction is A2, 0.52mm≤A2≤0.78mm. Figure 15 As shown, after mold closing, along the second direction, the distance between the portion of the cavity wall of the mounting cavity 93 opposite to the electronic component 600 and the assembly 190 is B2, 0.56mm≤B2≤0.84mm. Figure 15 and Figure 16As shown, after mold closing, the distance between the cavity wall of the mounting cavity 93 and the dome switch 200 is C2, where 0.15mm ≤ C2 ≤ 0.24mm. The injection molding rod 94 extrudes the epoxy molding compound into the second chamber 932 and expels air from the second chamber 932 through the vent of at least one of the first mold 91 and the second mold 92. After air expulsion, the epoxy molding compound is cured, and the second mold 92 is opened after complete curing. After mold opening, adhesive is applied to the dome switch 200 on the circuit board 100 using a dotting method. After mold opening, the cured body and the encapsulated adhesive are laser-cut to form the molding layer 300 and the sealing part 400. For example, the value of A2 includes 0.55mm, 0.58mm, 0.6mm, 0.65mm, 0.68mm, 0.7mm, 0.72mm, and 0.75mm, etc., which are not listed here. Values ​​for B2 include 0.58mm, 0.59mm, 0.6mm, 0.65mm, 0.68mm, 0.7mm, 0.72mm, 0.75mm, and 0.8mm, etc., and will not be listed here. Values ​​for C2 include 0.16mm, 0.18mm, 0.2mm, 0.21mm, 0.22mm, and 0.23mm, etc., and will not be listed here. For example... Figure 17 As shown, along the first direction, the distance from the side of the sealing layer 300 away from the dome switch 200 to the sealing part 400 is X, where 0.16mm ≤ X ≤ 0.24mm. Along the first direction, the length of the sealing part 400 is Y1, where 0.15mm ≤ Y1 ≤ 0.2mm. Along the third direction, the length of the sealing part 400 is Y2, where 0.15mm ≤ Y2 ≤ 0.2mm. Values ​​of X include 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, and 0.23mm, etc., and are not listed here. Values ​​of Y1 include 0.16mm, 0.17mm, 0.18mm, and 0.19mm, etc., and are not listed here. Values ​​of Y2 include 0.16mm, 0.17mm, 0.18mm, and 0.19mm, etc., and are not listed here.

[0126] For example, in this application, the shape of the circuit board assembly 10 is laser-cut. (As...) Figure 14 As shown, along the first direction, the distance E4 from the side of the molding compound 300 away from the dome switch 200 to the dome switch 200 is greater than or equal to 0.15 mm and less than or equal to 0.2 mm. Therefore, the width of the circuit board assembly 10 is the width of the dome switch 200 in the first direction + 0.4 mm. Taking a width of 1.9 mm for the dome switch 200 in the first direction as an example, the width of the circuit board assembly 10 in this application can be 2.2 mm. The minimum width of a circuit board assembly in related technologies is 3.3 mm. Therefore, the width of the circuit board assembly 10 in this application can be optimized by 30%.

[0127] For example, in this application, the shape of the circuit board assembly 10 is laser-cut. (As...) Figure 17 As shown, along the first direction, the width of the circuit board assembly 10 is the width of the dome switch 200 in the first direction + 0.7 mm. Taking the width of the dome switch 200 in the first direction as 1.9 mm as an example, the width of the circuit board assembly 10 in this application can be 2.6 mm. The minimum width of the circuit board assembly in the related art is 3.3 mm. Therefore, the width of the circuit board assembly 10 in this application can be optimized by 21%.

[0128] For example, the electronic components 600 in this application are completely embedded in the molding compound 300, which helps to improve the waterproof capability and device pressure protection capability of the circuit board assembly 10. The electronic components 600 include chips, inductors, resistors, etc., which will not be listed here.

[0129] For example, such as Figure 2 As shown, electronic device 1 includes a frame 70, buttons 81, a battery cover 82, a screen 83, a motherboard 84, and a circuit board assembly 10. A third region 130 of the circuit board assembly 10 is electrically connected to the motherboard 84. The motherboard 84 can be replaced with a camera or a battery.

[0130] For example, such as Figure 8 As shown, the assembly to be assembled 190 includes a first insulating dielectric layer 150a, a second insulating dielectric layer 150b, a third insulating dielectric layer 150c, a first adhesive layer 170, a second adhesive layer 180, a wiring layer 142, a metal layer 141, and a reinforcing plate 500.

[0131] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0132] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for manufacturing a circuit board assembly, characterized in that, include: The assembly to be assembled is placed on the first mold. The assembly to be assembled includes a circuit board and a dome switch. The circuit board is located between the first mold and the dome switch. The first mold is used to support the assembly to be assembled. The second mold is fastened to the side of the circuit board away from the first mold, and an installation cavity is formed between the second mold and the circuit board. The dome switch is located in the installation cavity. The second mold is used to fix the assembly to be assembled and cooperates with the circuit board to form the installation cavity. Inject molding compound into the mounting cavity and cure the molding compound to form a cured body; Laser cutting of the cured body to form a molding layer and a sealing portion; or Apply adhesive between the cured body and the dome switch, and then laser-cut the cured body and the adhesive to form a molding layer and a sealing portion; The sealing portion is located between the molding layer and the dome switch. Both the molding layer and the sealing portion are arranged around the dome switch. The sealing portion is used to seal the connection between the circuit board, the molding layer and the dome switch, and a portion of the dome switch protrudes from the sealing portion to the side of the circuit board away from the sealing portion.

2. The method for preparing the circuit board assembly according to claim 1, characterized in that, Based on the case where adhesive is applied between the cured body and the dome switch, the second mold has a baffle that divides the mounting cavity into a first chamber and a second chamber, the dome switch being located in the first chamber and having a gap between the dome switch and the wall of the first chamber; The steps for forming the cured body specifically include: injecting molding compound into the second chamber and curing the molding compound.

3. The method for preparing the circuit board assembly according to claim 1, characterized in that, When the cured body is laser-cut to form the encapsulation layer and the sealing portion, the second mold snaps onto the side of the circuit board opposite to the first mold and extrudes the dome switch.

4. The method for preparing a circuit board assembly according to any one of claims 1 to 3, characterized in that, The assembly to be assembled also includes electronic components, which are located within the mounting cavity and are encapsulated by the cured body.

5. The method for manufacturing a circuit board assembly according to any one of claims 1 to 3, characterized in that, The circuit board includes a first region, and the step of laser cutting the cured body to form a molding layer specifically includes: Using the outer edge of the first region as a reference edge, the cured body is laser-cut so that the outer contour of the encapsulation layer overlaps with the outer edge of the first region; Wherein, along the first direction, the width of the portion of the circuit board located between the dome switch and the outer edge of the first region is greater than or equal to 0.15 mm.

6. A circuit board assembly, characterized in that, The circuit board assembly is manufactured by the method for manufacturing a circuit board assembly as described in any one of claims 1 to 5, and the circuit board assembly comprises: Circuit board; A dome switch is stacked on one side of the circuit board, and the dome switch is electrically connected to the circuit board; A molding compound layer, wherein the molding compound layer and the dome switch are located on the same side of the circuit board, and the molding compound layer and the circuit board are connected; A sealing portion is located between the molding compound and the dome switch, both the molding compound and the sealing portion are arranged around the dome switch, and the sealing portion is used to seal the connection between the circuit board, the molding compound and the dome switch; A portion of the dome switch protrudes from the sealing portion and faces away from the circuit board.

7. The circuit board assembly according to claim 6, characterized in that, The sealing portion includes a molding portion, and the molding portion and the molding layer are an integral structure; or The sealing part includes an encapsulating adhesive part.

8. The circuit board assembly according to claim 6 or 7, characterized in that, There are multiple dome switches and multiple sealing portions. Multiple dome switches are located on the same side of the circuit board. The molding layer is arranged around each dome switch. Each sealing portion mates with one dome switch.

9. The circuit board assembly according to claim 6 or 7, characterized in that, The circuit board includes a first region, which connects the molding layer, the sealing portion, and the dome switch. The outer contour of the molding layer is formed by laser cutting, and the outer contour of the molding layer overlaps with the outer edge of the first region. Along the first direction, the width of the portion of the circuit board located between the dome switch and the outer edge of the first region is greater than or equal to 0.15 mm.

10. The circuit board assembly according to claim 9, characterized in that, The circuit board is a flexible circuit board, and the circuit board assembly further includes: A reinforcing plate is connected to the side of the circuit board opposite to the dome switch.

11. The circuit board assembly according to claim 10, characterized in that, The thickness of the reinforcing plate is greater than or equal to 0.25 mm; and / or The reinforcing plate includes a steel plate and / or an epoxy board.

12. The circuit board assembly according to claim 10, characterized in that, Along a direction perpendicular to the dome switch to the circuit board, the circuit board further includes a second region and a third region, the second region being connected between the first region and the third region; The circuit board includes multiple metal layers and multiple insulating dielectric layers, wherein the multiple metal layers are stacked, and an insulating dielectric layer is disposed between any two adjacent metal layers; The number of metal layers in either the first region or the third region is greater than the number of metal layers in the second region. A portion of the reinforcing plate is disposed opposite to the first region, and another portion of the reinforcing plate is disposed opposite to the third region.

13. The circuit board assembly according to claim 6 or 7, characterized in that, The circuit board is provided with conductive holes, and a wiring layer is provided on the side of the circuit board opposite to the dome switch. The dome switch is electrically connected to the wiring layer through the conductive holes.

14. The circuit board assembly according to claim 6 or 7, characterized in that, Also includes: At least one electronic component, wherein at least one said electronic component and the dome switch are located on the same side of the circuit board and the electronic component is electrically connected to the circuit board, and the molding compound covers each said electronic component.

15. An electronic device, characterized in that, include: A frame, wherein an opening is provided on the side of the frame; A button is located at the opening, and the button is movably connected to the frame. and The circuit board assembly as described in any one of claims 6 to 14, wherein the circuit board assembly is disposed in the frame, and the button is disposed opposite to the portion of the dome that protrudes from the sealing portion.

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