Small-current and large-breaking-capacity surface mount fuse and preparation method thereof

Abstract

This invention provides a surface-mount fuse with low current and high breaking capacity, and its manufacturing method. The manufacturing method includes: S1, providing a support portion; the support portion includes a first substrate and a first metal film, the first metal film being tightly attached to a first surface of the first substrate, and a fusing unit being formed on the first metal film, the mechanical stress of the fusing unit being enhanced by the first substrate; S2, providing a cavity portion; the cavity portion includes a second substrate and a groove formed by machining, the groove being formed on the first surface of the second substrate and extending into the interior of the second substrate, wherein the depth of the groove is less than the thickness of the second substrate; S3, attaching the support portion and the cavity portion together to form a fuse body portion, wherein the groove and the support portion are attached to form the cavity. This invention, by setting a support portion including a fusing unit manufactured by a special process, achieves a new type of fuse with a fusing unit that is not easily broken by mechanical stress during application and has a high breaking capacity for low current.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit protection, and in particular to a surface mount fuse and its preparation method. Background Technology

[0002] In the field of electronic circuit protection, surface mount fuses play a vital role and are widely used. These fuses are mainly divided into two types: wire-in-air fuses and epoxy resin frame fuses. However, both types of fuses use metallurgical techniques to fabricate thin-wire fuse elements. Due to the excessively small diameter of the fuse element, the wire is prone to breakage, affecting the reliability of the fuse. Furthermore, limitations in machining precision make it difficult to reduce their size, limiting their minimum protection current and breaking capacity, thus failing to meet the miniaturization and high-performance requirements of electronic equipment. In addition, both types of fuses suffer from poor dimensional consistency, affecting the consistency of the final product's protective effect.

[0003] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a surface mount fuse with small current and large breaking capacity and its preparation method, which solves the problems of excessively thin and easily broken fusing units, insufficient fuse reliability, excessively large protection current threshold, insufficient breaking capacity, and insufficient size consistency of surface mount fuses in the prior art.

[0005] To achieve the above and other related objectives, the present invention provides a method for preparing a surface-mount fuse, comprising:

[0006] Step S1: Provide a support portion; the support portion includes a first substrate and a first metal film, the first metal film is closely attached to the first surface of the first substrate, wherein a fusion unit is formed on the first metal film, and the mechanical stress of the fusion unit is enhanced by the first substrate;

[0007] Step S2: Provide a cavity portion; the cavity portion includes a second substrate and a groove, the groove is formed on a first surface of the second substrate by mechanical processing and extends into the interior of the second substrate, wherein the depth of the groove is less than the thickness of the second substrate;

[0008] Step S3: The support portion and the cavity portion are fitted together to form a fuse body portion, wherein the groove and the support portion are fitted together to form a cavity, so that the fuse unit is disposed in the cavity.

[0009] Optionally, the fusible element comprises at least one material selected from pure copper, pure tin, pure nickel, pure aluminum, pure silver, and metal alloys.

[0010] Optionally, the step of forming the fuse unit includes: performing a patterned etching process on the first metal film to form the body portion of the fuse unit, and then performing a patterned thickening process on the first metal film to form a connection structure of the fuse unit, wherein the connection structure is disposed at both ends of the body portion, and the width of the connection structure is greater than the width of the body portion.

[0011] Optionally, the step of forming the support portion further includes: providing a second metal film and attaching the second metal film to a second surface of the first substrate, wherein the second surface of the first substrate is configured as the surface of the support portion away from the cavity portion.

[0012] Optionally, the step of forming the cavity portion further includes: providing a third metal film and attaching the third metal film to a second surface of the second substrate, wherein the second surface of the second substrate is configured as the surface of the cavity portion away from the support portion.

[0013] Optionally, the step of bonding the support portion to the cavity portion includes: providing an adhesive material layer and performing a graphic processing on the adhesive material layer; placing the graphic processed adhesive material layer on the contact portion between the support portion and the cavity portion, and bonding and connecting the support portion and the cavity portion through a pressing process.

[0014] Optionally, the preparation method further includes an electrode formation step, comprising:

[0015] A first power through hole and a second power through hole are respectively provided at the left and right ends of the fuse body. The first power through hole and the second power through hole both penetrate the support part and the cavity part along the direction from the support part to the cavity part, and two electrodes are respectively formed by electroplating based on the first power through hole and the second power through hole.

[0016] Optionally, a first electrical blind hole and a second electrical blind hole are provided at the left and right ends of the support portion. The first electrical blind hole and the second electrical blind hole penetrate the support portion along the direction from the support portion to the cavity portion until they contact the fuse unit. Two electrodes are formed by electroplating based on the first electrical blind hole and the second electrical blind hole.

[0017] Optionally, a third electrical blind hole and a fourth electrical blind hole are provided at the left and right ends of the cavity. The third electrical blind hole and the fourth electrical blind hole penetrate the cavity in the direction from the cavity to the support until they contact the fuse unit. Two electrodes are formed by electroplating based on the third electrical blind hole and the fourth electrical blind hole.

[0018] Optionally, a first side electrode and a second side electrode are provided on the left and right end faces of the cavity; a first end electrode is prepared on the surface of the first side electrode to electrically connect the first end electrode to the first end of the fuse unit through the first side electrode; a second end electrode is prepared on the surface of the second side electrode to electrically connect the second end of the fuse unit through the second side electrode; the first end electrode and the second end electrode cover the left and right end faces of the cavity.

[0019] Optionally, the preparation method further includes the step of connecting the fusing unit to the corresponding electrode, including,

[0020] When the first metal film is patterned to form only the body portion, the fuse unit is electrically connected to the corresponding electrode through the body portion.

[0021] When the first metal film is patterned to form a connection structure, the fusion unit is electrically connected to the corresponding electrode through the connection structure.

[0022] To achieve the above and other related objectives, the present invention provides a surface mount fuse with low current and high breaking capacity, comprising: a support portion and a cavity portion;

[0023] The support portion and the cavity portion are fitted together to form the fuse body portion. The cavity portion has a machined groove on the side near the support portion to fit with the support portion to form a cavity.

[0024] The support portion includes a fusible element, which is disposed close to the surface of the support portion near the cavity portion to increase the mechanical stress of the fusible element, and the fusible element is disposed in the cavity.

[0025] Optionally, the fusion unit is configured as a rectangular metal film or a serpentine metal film.

[0026] Optionally, the low-current, high-breaking-capacity surface mount fuse further includes a bonding portion; the bonding portion is disposed between the support portion and the cavity portion, and is used to bond and connect the support portion and the cavity portion.

[0027] Optionally, the surface mount fuse with low current and high breaking capacity further includes two electrodes; each electrode is disposed at the left and right ends of the fuse body and is electrically connected to the two ends of the fusing unit.

[0028] Optionally, the two electrodes include a first power through hole and a second power through hole respectively provided at the left and right ends of the fuse body portion; the first power through hole and the second power through hole both penetrate the support portion and the cavity portion along the direction from the support portion to the cavity portion; the two electrodes also include two electroplated layer structures respectively prepared by electroplating along the surfaces of the first power through hole and the second power through hole.

[0029] Optionally, the two electrodes include a first electrical blind hole and a second electrical blind hole provided at the left and right ends of the support portion; the first electrical blind hole and the second electrical blind hole both penetrate the support portion along the direction from the support portion to the cavity portion until they contact the fuse unit; the two electrodes also include two electroplated layer structures prepared by electroplating along the surfaces of the first electrical blind hole and the second electrical blind hole respectively.

[0030] Optionally, the two electrodes include a third electrical blind hole and a fourth electrical blind hole at the left and right ends of the cavity; the third electrical blind hole and the fourth electrical blind hole both penetrate the cavity in the direction from the cavity to the support until they contact the fuse unit; the two electrodes also include two electroplated layer structures prepared by electroplating along the surfaces based on the third electrical blind hole and the fourth electrical blind hole respectively.

[0031] Optionally, the two electrodes include a first side electrode and a second side electrode provided on the left and right end faces of the cavity; the two electrodes also include a first end electrode prepared on the surface of the first side electrode and a second end electrode prepared on the surface of the second side electrode; the first end electrode is electrically connected to the first end of the fuse unit through the first side electrode, and the second end electrode is electrically connected to the second end of the fuse unit through the second side electrode; the first end electrode and the second end electrode cover the left and right end faces of the cavity.

[0032] Optionally, the fuse unit includes a body portion and a connecting structure. The connecting structure is disposed at both ends of the body portion and extends outward from both ends to connect to the corresponding electrodes. The width of the connecting structure is greater than the width of the body portion.

[0033] As described above, the surface mount fuse with low current and high breaking capacity and its preparation method of the present invention have the following beneficial effects:

[0034] This invention provides a new type of surface mount fuse by incorporating a support portion for the fuse unit, which is manufactured using a special process. This allows the fuse unit to be less prone to breakage under mechanical stress during manufacturing and application, while also exhibiting strong current protection capability, strong breaking capacity, good product consistency, and smaller product size.

[0035] The method of the present invention is simple and has a simple structure, and can be applied to most electronic circuit working environments. Attached Figure Description

[0036] Figure 1 The diagram shows the steps of the method for preparing a surface-mount fuse with low current and high breaking capacity according to the present invention.

[0037] Figure 2 The diagram shown illustrates the structure of the surface mount fuse with low current and high breaking capacity according to the present invention.

[0038] Figure 3 The image shown is a top view of the first substrate of the present invention.

[0039] Figure 4 The image shown is a top view of the first substrate with the first metal film attached according to the present invention.

[0040] Figure 5 This invention is shown to be related to... Figure 4 The top view of the fusing unit is obtained by graphically representing the first metal film.

[0041] Figure 6 The image shown is a top view of the second substrate of the present invention.

[0042] Figure 7 This invention is shown to be related to... Figure 6 The second substrate is machined to obtain a top view of the groove.

[0043] Figure 8 This invention is shown as Figure 7 A side view of the groove produced by machining.

[0044] Figure 9 The image shown is a top view of the adhesive material layer of this invention.

[0045] Figure 10 The image shown is a top view of the graphic representation of the adhesive material layer according to the present invention.

[0046] Figure 11 The image shown is a top view of the first electrode of the present invention before its fabrication.

[0047] Figure 12 The diagram shown is a structural schematic of the first electrode of the present invention.

[0048] Figure 13The image shown is a top view of the second type of electrode before its fabrication according to the present invention.

[0049] Figure 14 The diagram shown is a structural schematic of the second type of electrode of the present invention.

[0050] Figure 15 The image shown is a top view of the third type of electrode before its fabrication according to the present invention.

[0051] Figure 16 The diagram shown is a structural schematic of the third type of electrode of the present invention.

[0052] Figure 17 The image shown is a top view of the fourth type of electrode before its fabrication according to the present invention.

[0053] Figure 18 The image shown is a side view of the fourth type of electrode before its fabrication according to the present invention.

[0054] Figure 19 The diagram shown is a structural schematic of the fourth type of electrode of the present invention.

[0055] Component designation explanation

[0056] 1. Surface mount fuse with low current and high breaking capacity

[0057] 11 Support section

[0058] 111 First substrate

[0059] 112 First Metallic Film

[0060] 1121 Fuse Unit

[0061] 1121a Main Body

[0062] 1121b Connection Structure

[0063] 12. Hollow section

[0064] 121 Second substrate

[0065] 1211 Groove

[0066] 13. Adhesive Material Layer

[0067] 131 Fitting Part

[0068] 132 Penetrating section

[0069] 14 electrodes

[0070] 141 First power through hole

[0071] 142 Second power through hole

[0072] 143 First blind hole

[0073] 144 Second electrical blind hole

[0074] 145 Third blind hole

[0075] 146 Fourth electrical blind hole

[0076] 147 First side hole

[0077] 148 Second side hole Detailed Implementation

[0078] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0079] Please see Figures 1 to 19 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0080] Surface mount fuses are mainly divided into two types: one is the wire-in-air fuse, and the other is the epoxy resin frame fuse.

[0081] The fuse element of an air-fuse fuse is typically a thin wire manufactured using metallurgical processes. However, this type of fuse element has several drawbacks. First, its extremely small diameter makes it prone to breakage during use, affecting the fuse's reliability. Second, limitations in machining precision restrict the size of the fuse element, making it difficult to meet the demands of increasingly miniaturized and high-performance electronic devices, as well as the requirement for dimensional consistency, thus impacting the consistency of the fuse's protective effect. Furthermore, air-fuse fuses require welding to connect the fuse element to external terminals, a method prone to defects such as incomplete or false soldering, which can cause the fuse element to break off from the solder, affecting the fuse's normal operation. Moreover, the air-fuse structure cannot achieve a complete seal, severely limiting its application in harsh environments; for example, in environments with high humidity, high temperature, or corrosive gases, the fuse's performance may be severely affected, or it may even fail to function properly, significantly reducing its applicability.

[0082] Epoxy resin frame fuses represent an improvement on the housing of air-fuse fuses. They utilize a printed circuit board (PCB) fabrication process on a substrate to create the housing, replacing the ceramic or melamine housing of traditional air-fuse fuses. This design addresses, to some extent, the sealing issues of traditional surface-mount fuses, making them suitable for environments with high humidity, high temperature, or corrosive gases. However, the structure of the fusing unit in epoxy resin frame fuses remains unchanged. The fusing unit still consists of a thin wire, fabricated using metallurgical processes, that passes directly through the epoxy resin frame. This results in the same issues of easy breakage and difficulty in ensuring consistent product performance.

[0083] To solve the above technical problems, such as Figure 1 As shown, this embodiment provides a method for preparing a surface-mount fuse with low current and high breaking capacity, used to prepare a surface-mount fuse 1 with low current and high breaking capacity; wherein, the method for preparing the surface-mount fuse 1 with low current and high breaking capacity includes at least the following steps.

[0084] like Figure 1 and Figure 2 As shown, in step S1, a support portion 11 is provided; the support portion 11 includes a first substrate 111 and a first metal film 112; the first metal film 112 is tightly disposed on the first surface of the first substrate 111 (e.g., ...). Figure 2 (The lower surface of the first substrate 111 is shown); a fusing unit 1121 is formed on the first metal film 112, and the mechanical stress of the fusing unit 1121 is strengthened by the first substrate 111.

[0085] Specifically, in this embodiment, the first substrate 111 includes, but is not limited to, an FR4 carrier board, a BT carrier board, and an ABF carrier board. The FR4 carrier board is made of glass fiber reinforced epoxy resin and has good electrical insulation, mechanical strength, and flame retardancy. The BT carrier board is a carrier board prepared using a high-performance epoxy resin material called bismaleimide triazine. The ABF carrier board is a carrier board formed from a thin film material used to construct a multilayer circuit board.

[0086] Specifically, in this embodiment, the fuse unit 1121 comprises at least one material selected from pure copper, pure tin, pure nickel, pure aluminum, pure silver, and metal alloys. That is, the material of the first metal film 112 is selected from at least one of these materials. In this embodiment, the fuse unit 1121 is selected from pure copper, metal alloy films, or alloy materials formed based on additional processing techniques (such as copper-tin plating). The thickness of the fuse unit 1121 is set to 0.1µm to 0.1mm, including 0.5µm, 0.75µm, and 0.8µm. In this embodiment, pure copper is preferred. Based on current advancements in metal film preparation technology, mature pure copper foil can achieve a thickness of 1.5µm. Further, through sputtering and vapor deposition processes, pure copper foil can be reduced to 0.1µm. At this point, the fuse unit 1121 can achieve a smaller current protection capability, making it easier to realize low-current products and ensuring manufacturing feasibility. At the same time, it should be emphasized that, since the pure copper foil itself is relatively thin at this time, it needs to be supported by the first substrate in this embodiment to further ensure the reliability of the fusing unit in the subsequent preparation process and use.

[0087] Specifically, such as Figures 3-5 As shown, the steps for forming the fuse unit 1121 include: performing a patterned etching process on the first metal film 112 to form the body portion 1121a of the fuse unit 1121, and then performing a patterned thickening process on the first metal film 112 to form the connection structure 1121b of the fuse unit 1121. The connection structure 1121b is disposed at both ends of the body portion 1121a, and the width of the connection structure 1121b is greater than the width of the body portion 1121a, and the thickness of the connection structure 1121b is greater than the thickness of the body portion 1121a.

[0088] In this embodiment, the first metal film 112 is patterned to form the body portion 1121a of the fuse unit and the connecting structure 1121b, as shown below. Figure 5As shown, the connecting structure 1121b is disposed at both ends of the body portion 1121a of the fuse unit. The width of the connecting structure 1121b is greater than the width of the body portion 1121a. The body portion 1121a is connected outward through the wider connecting structure 1121b, improving reliability. Meanwhile, because the body portion 1121a and the connecting structure 1121b of the fuse unit 1121 are etched using a patterning process, the fuse unit 1121 is integrally formed, increasing structural stress and preventing wire breakage. This avoids the breakage problem that might occur when soldering the fuse unit 1121, thus enhancing the reliability of the surface mount fuse 1 with its small current and high breaking capacity. Furthermore, the thickness of the body portion 1121a and the connecting structure 1121b of the fuse unit 1121 is inconsistent to improve structural reliability. The specific thickness can be determined based on the specific configuration of the fuse unit 1121. In another embodiment, the body portion 1121a and the connecting structure 1121b can be manufactured separately for connection. The actual connection method is not limited to this embodiment. In this embodiment, the body portion 1121a is further provided with connecting portions at both ends (that is, the irregular quadrilateral between the body portion 1121a and the connecting structure 1121b). In other embodiments, the connecting portions may be omitted, and the two ends of the first metal film of the body portion 1121a may be patterned and thickened to obtain the thickened connecting structure 1121b. The thickened connecting structure includes, but is not limited to, electroplating.

[0089] It should be noted that, compared to the fine wires prepared by metallurgical processes, the fuse unit 1121 in this embodiment is a thin film strip, and the fuse unit 1121 is formed by a special process applied to the surface of the first substrate 111 in a patterned manner. The shape (rectangular in this embodiment) and width (which determine properties such as the minimum protection current) of the fuse unit 1121 can be achieved through precision PCB processing and semiconductor processing, thereby further reducing the rated minimum protection current from 0.5A, making it suitable for scenarios with higher protection requirements. At the same time, using precision PCB processing and semiconductor processing to manufacture the fuse unit 1121 can further improve the product's processing accuracy and reliability, and effectively improve the product's dimensional consistency.

[0090] It should be further explained that, since the metal film of the fuse unit 1121 is relatively thin, the fuse unit 1121 is manufactured by first attaching the first metal film 112 to the first substrate 111. The good support provided by the first substrate 111 ensures that the fuse unit 1121 has sufficient strength during the process of forming the fuse unit 1121, the subsequent assembly of the surface mount fuse, and the subsequent use of the surface mount fuse. It is not easily affected by mechanical stress, such as assembly stress, vibration stress, or other mechanical impacts that may occur during the formation of the fuse unit 1121, the subsequent assembly process, and the use process, which greatly improves the reliability, product consistency, and service life of the surface mount fuse manufactured in this embodiment.

[0091] Specifically, the step of forming the support portion 11 further includes providing a second metal film (not shown in the figure) and attaching the second metal film to the second surface of the first substrate 111; the second surface of the first substrate 111 is set as the surface of the support portion 11 away from the cavity portion 12.

[0092] In this embodiment, with Figure 2 As explained, the upper and lower surfaces of the first substrate 111 are covered with different metal films. The metal film on the upper surface is used to form the outer shell, and the metal film on the lower surface is used to form the fuse unit 1121.

[0093] like Figure 1 , Figure 2 as well as Figures 6-8 As shown, in step S2, a cavity portion 12 is provided; wherein, the cavity portion 12 includes a second substrate 121 and a groove 1121, the groove 1121 is formed on the first surface of the second substrate 121 by mechanical processing and extends into the interior of the second substrate 121, and the depth of the groove 1211 is less than the thickness of the second substrate 121.

[0094] In this embodiment, as Figure 8 As shown, the groove 1211, which is machined by milling process according to the preset design size requirements, does not penetrate the entire substrate. The lower cavity structure of the fusing unit 1121 and the special process ensure that the fusing unit 1121 can withstand greater breaking capacity when it is melted.

[0095] Specifically, the step of forming the cavity portion 12 further includes providing a third metal film (not shown in the figure) and attaching the third metal film to the second surface of the second substrate 121; the second surface of the second substrate 121 is set as the surface of the cavity portion 12 away from the support portion 11.

[0096] In this embodiment, with Figure 2To explain, the upper surface of the second substrate 121 is machined by milling to create a groove 1211, and the lower surface is provided with a third metal film to form the final shell.

[0097] like Figure 1 and Figure 2 As shown, in step S3, the support part 11 and the cavity part 12 are attached together to form the fuse body part, wherein the groove 1211 and the support part 11 are attached together to form a cavity, so as to place the fuse unit 1121 in the cavity.

[0098] Specifically, such as Figure 2 , Figure 9 and Figure 10 As shown, the step of bonding the support portion 11 to the cavity portion 12 includes: providing an adhesive material layer 13 and performing graphic processing on the adhesive material layer 13; placing the graphic processed adhesive material layer 13 at the contact portion between the support portion 11 and the cavity portion 12, and bonding and connecting the support portion 11 and the cavity portion 12 through a pressing process.

[0099] In this embodiment, the adhesive material layer 13 is divided into an adhesive portion 131 and a through portion 132. The through portion 132 is used to connect the fusion unit 1121 and the cavity, while the adhesive portion 131 is used to fix the upper support portion 11 and the lower cavity portion 12. Therefore, the shape of the adhesive portion 131 depends on the shape of the contact portion between the support portion 11 and the cavity portion 12.

[0100] In this embodiment, the adhesive material layer 13 includes raw material sheets such as adhesive sheets, fiberglass cloth, copper foil, core, and resin. The adhesive sheet is a material used in multilayer PCB manufacturing, typically made of fiberglass cloth (or other reinforcing materials) impregnated with epoxy resin (or other resins). It is in a semi-cured state (B-stage) at room temperature and can be fully cured by heating and pressurizing, thereby bonding different copper foil layers or cores together. In this embodiment, other semi-cured sheets can also be used; any arrangement that achieves reinforcement is within the scope of protection of this embodiment.

[0101] It should be noted that the surface mount fuse formed in this embodiment has a good encapsulation effect, meets the usage requirements of various harsh environments, and is suitable for most electrical working environments.

[0102] like Figure 2 As shown, the surface mount fuse preparation method also includes the electrode 14 forming step.

[0103] Specifically, in the first example, such as Figure 11 and Figure 12As shown, the electrode forming step includes: providing a first through hole 141 and a second through hole 142 at the left and right ends of the fuse body, respectively; both the first through hole 141 and the second through hole 142 penetrate the support portion 11 and the cavity portion 12 along the direction from the support portion 11 to the cavity portion 12, and two electrodes are formed by electroplating based on the first through hole 141 and the second through hole 142. In this embodiment, the electrodes are implemented using the plated through hole (PTH) method in PCB technology. In this case, the electrical connection of the electrodes mainly depends on the copper plating layer on the inner wall of the PTH through hole and the solder terminals at the upper and lower ends (not shown in the figure), and is non-directional.

[0104] Specifically, in the second example, such as Figure 13 and Figure 14 As shown, the electrode forming step includes: providing a first electrical blind hole 143 and a second electrical blind hole 144 at both ends of the support portion 11; both the first electrical blind hole 143 and the second electrical blind hole 144 penetrate the support portion 11 along the direction from the support portion 11 to the cavity portion 12 until they contact the fuse unit 1121, and two electrodes are formed by electroplating based on the first electrical blind hole 143 and the second electrical blind hole 144. In this embodiment, the first electrical blind hole 143 and the second electrical blind hole 144 are formed on the first substrate 111, and metal plating is performed on the blind holes to realize electrode fabrication, and the blind holes are connected to a single-sided solder terminal. At this time, the other surface of the surface mount fuse (the lower surface of the cavity portion 12) has no solder terminal.

[0105] Specifically, in the third example, such as Figure 15 and Figure 16 As shown, the electrode forming step includes: a third electrical blind hole 145 and a fourth electrical blind hole 146 are provided at both ends of the cavity 12; the third electrical blind hole 145 and the fourth electrical blind hole 146 penetrate the cavity 12 along the direction from the cavity 12 towards the support portion 11 until they contact the fuse unit 1121, and two electrodes are formed by electroplating based on the third electrical blind hole 145 and the fourth electrical blind hole 146. In this embodiment, the third electrical blind hole 145 and the fourth electrical blind hole 146 are prepared on the second substrate 121, and metal plating is performed on the blind holes to realize electrode fabrication. The blind holes are then connected to a single-sided solder terminal. At this time, the other surface of the surface mount fuse (the upper surface of the support portion 11) has no solder terminal.

[0106] Specifically, in the fourth example, such as Figures 17-19As shown, the electrode forming step includes: providing a first side electrode 147 and a second side electrode 148 on the left and right end faces of the cavity portion 12; forming a first end electrode on the surface of the first side electrode 147 to electrically connect the first end electrode to the first end of the fuse unit 1121 through the first side electrode 147; forming a second end electrode on the surface of the second side electrode 148 to electrically connect the second end electrode to the second end of the fuse unit 1121 through the second side electrode; the first end electrode and the second end electrode cover the left and right end faces of the cavity portion 12. In this embodiment, the second substrate 121 also drills side through holes (such as those for side hole connections) while forming the groove 1211. Figure 17 The first side electrical hole 147 and the second side electrical hole 148 on the left and right sides are used to form the electrode after the cavity part 12 and the support part 11 are attached. The end electrode is then made at the two side electrical hole positions to finally form the electrode.

[0107] It should be noted that during the electrode formation process described above, the patterned shape of the adhesive material layer needs to be set according to the actual shapes of the first substrate 111 and the second substrate 121 to be bonded. For example, in the fourth example, the second substrate 121 forms a first side electrical hole 147 and a second side electrical hole 148 while forming the groove 1211 manufactured by machining. Therefore, the corresponding adhesive material layer 13 needs to be modified accordingly.

[0108] It should be further explained that different electrode formation methods can be applied to different application scenarios of surface mount fuses, that is: the positional relationship of surface mount with other electronic components can be set directly by soldering terminals, which has a wide range of applicability.

[0109] In this embodiment, the surface mount fuse manufacturing method further includes the step of connecting the fusing unit 1121 to the corresponding electrode.

[0110] In the first embodiment, when the first metal film 112 is patterned to form only the body portion 1121a of the fuse unit, the fuse unit is electrically connected to the corresponding electrode through the body portion. That is, when the pattern is patterned, only the fuse unit is formed, and each electrode is directly electrically connected to the body portion of the fuse terminal 1121.

[0111] In the second embodiment, when the first metal film 112 is patterned to form a connection structure 1121b, the fuse unit is electrically connected to the corresponding electrode through the connection structure 1121b. That is, during patterning, the body portion 1121a of the fuse unit 1121 and the connection structure 1121b are formed, and each electrode is electrically connected to the corresponding electrode based on the connection structure 1121b. At this time, the connection between the fuse unit and the external terminal does not directly utilize materials such as solder, thus resulting in higher reliability.

[0112] like Figure 2As shown, this embodiment also provides a surface patch fuse with low current and high breaking capacity, including a support portion 11 and a cavity portion 12; in one example, the surface patch fuse 1 with low current and high breaking capacity of this embodiment is prepared by the preparation method described above.

[0113] like Figure 2 As shown, the support portion 11 and the cavity portion 12 are fitted together to form the fuse body portion. The cavity portion 12 has a machined groove on the side near the support portion 11 so as to fit with the support portion 11 to form a cavity.

[0114] In this embodiment, the cavity portion 12 includes a second substrate 121; a groove 1211 is machined onto the first surface of the second substrate 121, and the depth of the groove 1211 is less than the thickness of the second substrate 121. In this embodiment, the thickness of the second substrate 121 is set to 0.06mm to 1.0mm, such as 0.2mm, 0.5mm, or 0.75mm.

[0115] like Figure 2 As shown, the support portion 11 includes a fusing unit 1121; the fusing unit 1121 is disposed in close contact with the surface of the support portion 11 near the cavity portion 12 to improve the mechanical stress of the fusing unit 1121; the fusing unit 1121 is disposed in the cavity. Since the support portion is present on one side of the fusing unit 1121, it can prevent wire breakage due to the thinness of the fusing unit 1121 itself, as well as mechanical stress impacts during manufacturing, processing, and use.

[0116] Specifically, the fuse unit 1121 is configured as a rectangular metal film or a serpentine metal film. In fact, any shape that meets the fusing characteristics is within the protection scope of this embodiment. In this embodiment, the fuse unit 1121 is patterned to obtain a rectangular metal film. At this time, compared with the previous "line" shaped fuse unit 1121, the current that the fuse unit 1121 in this embodiment can withstand is guaranteed by the shape, thickness, and width of the patterned "pattern film". The thickness is achieved by the metal film attached to the surface of the substrate. The shape and width of the fuse unit 1121 can be guaranteed by precision PCB processing and semiconductor processing technology. Ultimately, a surface mount fuse 1 with a minimum single current of 20mA and a rated voltage of 250Vac can be achieved, which has a small current and a large breaking capacity. Meanwhile, the PCB manufacturing process used in this embodiment has high precision, ensuring product reliability and performance consistency. It can meet the design requirements for smaller products and can manufacture packages with various size codes, including but not limited to 0402, 0603, 0805, 1206, 1812, 2410, and 2920. These codes represent the component's length and width in imperial units (thousandths of an inch) or metric units (millimeters). For example, 0402 indicates a component length of 0.04 inches and a width of 0.02 inches.

[0117] like Figure 2 As shown, the surface mount fuse 1 with low current and high breaking capacity also includes a bonding part 131; the bonding part is disposed between the support part 11 and the cavity part 12, and is used to bond and connect the support part and the cavity part 12.

[0118] like Figure 2 As shown, the surface mount fuse 1 with low current and high breaking capacity also includes an electrode portion; the electrode portion is disposed at both ends of the fuse body, and the electrode portion electrically connects and leads out the fusing unit 1121. The surface mount fuse 1 with low current and high breaking capacity includes two electrodes 14, wherein the electrodes include different types, such as... Figures 11-19 There are 4 electrodes in different positions 14.

[0119] In the first example, the two electrodes 14 include a first through hole 141 and a second through hole 142 respectively provided at the left and right ends of the fuse body portion; the first through hole 141 and the second through hole 142 both penetrate the support portion 11 and the cavity portion 12 along the direction from the support portion 11 to the cavity portion 12; the two electrodes 14 also include two electroplated layer structures prepared by electroplating along the surfaces of the first through hole 141 and the second through hole 142 respectively, the specific configuration of which has been described above and will not be repeated here.

[0120] In the second example, the two electrodes 14 include a first electrical blind hole 143 and a second electrical blind hole 144 provided at the left and right ends of the support portion; the first electrical blind hole 143 and the second electrical blind hole 144 both penetrate the support portion along the direction from the support portion 11 to the cavity portion 12 until they contact the fuse unit 1121; the two electrodes 14 also include two electroplated layer structures prepared by electroplating along the surfaces of the first electrical blind hole 143 and the second electrical blind hole 144 respectively. The specific configuration has been described above and will not be repeated here.

[0121] In the third example, the two electrodes 14 include a third electrical blind hole 145 and a fourth electrical blind hole 146 at the left and right ends of the cavity portion 12; the third electrical blind hole 145 and the fourth electrical blind hole 146 both penetrate the cavity portion 12 along the direction from the cavity portion 12 toward the support portion 11 until they contact the fuse unit 1121; the two electrodes 14 also include two electroplated layer structures prepared by electroplating along the surfaces based on the third electrical blind hole 145 and the fourth electrical blind hole 146 respectively. The specific configuration has been described above and will not be repeated here.

[0122] In the fourth example, the two electrodes 14 include a first side electrode 147 and a second side electrode 148 disposed on the left and right end faces of the cavity portion 12; the two electrodes also include a first end electrode prepared on the surface of the first side electrode and a second end electrode prepared on the surface of the second side electrode; the first end electrode is electrically connected to the first end of the fuse unit 1121 through the first side electrode 147, and the second end electrode is electrically connected to the second end of the fuse unit 1121 through the second side electrode 148; the first end electrode and the second end electrode cover the left and right end faces of the cavity portion, and the specific arrangement has been described above and will not be repeated here.

[0123] In this embodiment, the fuse unit 1121 includes a body portion 1121a and a connecting structure 1121b; the connecting structure 1121b is disposed at both ends of the body portion 1121a of the fuse unit and extends outward from both ends to connect to the corresponding electrodes; wherein, the width of the connecting structure 1121b is greater than the width of the body portion 1121a to improve the reliability of the product. The specific settings have been described above and will not be repeated here.

[0124] In summary, this invention provides a surface-mount fuse with low current and high breaking capacity, and its manufacturing method. The manufacturing method includes: S1, providing a support portion; the support portion includes a first substrate and a first metal film, the first metal film being tightly attached to a first surface of the first substrate, and a fusing unit being formed on the first metal film, the mechanical stress of the fusing unit being strengthened by the first substrate; S2, providing a cavity portion; the cavity portion includes a second substrate and a groove formed by machining, the groove being formed on the first surface of the second substrate and extending into the interior of the second substrate, wherein the depth of the groove is less than the thickness of the second substrate; S3, attaching the support portion and the cavity portion together to form a fuse body portion, wherein the groove and the support portion are attached to form the cavity. This invention, by providing a support portion including a fusing unit manufactured by a special process, achieves a new type of fuse with a fusing unit that is not easily broken by mechanical stress during application and has a low current and high breaking capacity. The above embodiments are only illustrative of the principles and effects of this invention and are not intended to limit this invention. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of this invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention shall still be covered by the claims of this invention.

Claims

1. A method for preparing a surface mount fuse with low current and high breaking capacity, characterized in that, The preparation method includes at least: Step S1: Provide a support portion; the support portion includes a first substrate and a first metal film, the first metal film is closely attached to the first surface of the first substrate, wherein a fusion unit is formed on the first metal film, and the mechanical stress of the fusion unit is enhanced by the first substrate; Step S2: Provide a cavity portion; the cavity portion includes a second substrate and a groove, the groove is formed on a first surface of the second substrate by mechanical processing and extends into the interior of the second substrate, wherein the depth of the groove is less than the thickness of the second substrate; Step S3: The support portion and the cavity portion are fitted together to form a fuse body portion, wherein the groove and the support portion are fitted together to form a cavity, so that the fuse unit is disposed in the cavity; The preparation method further includes an electrode forming step, comprising: setting two electrodes at the left and right ends of the fuse body, and electrically connecting the two electrodes to the two ends of the fuse unit respectively. The preparation method further includes the step of connecting the fusing unit to the corresponding electrode, including: when the first metal film is patterned to form only the body portion, the fusing unit is electrically connected to the corresponding electrode through the body portion; when the first metal film is patterned to form a connection structure, the fusing unit is electrically connected to the corresponding electrode through the connection structure.

2. The method for preparing a surface-mount fuse according to claim 1, characterized in that: The fusion unit comprises at least one material selected from pure copper, pure tin, pure nickel, pure aluminum, pure silver, and metal alloys.

3. The method for preparing a surface mount fuse with low current and high breaking capacity according to claim 2, characterized in that: The steps for forming the fuse unit include: performing patterned etching on the first metal film to form the body portion of the fuse unit, and then performing patterned thickening on the first metal film to form the connection structure of the fuse unit, wherein the connection structure is disposed at both ends of the body portion, and the width of the connection structure is greater than the width of the body portion.

4. The method for preparing a surface mount fuse with low current and high breaking capacity according to claim 1, characterized in that: The step of forming the support portion further includes: providing a second metal film and attaching the second metal film to a second surface of the first substrate, wherein the second surface of the first substrate is configured as the surface of the support portion away from the cavity portion; And / or, The step of forming the cavity portion further includes: providing a third metal film and attaching the third metal film to the second surface of the second substrate, wherein the second surface of the second substrate is configured as the surface of the cavity portion away from the support portion.

5. The method for preparing a surface mount fuse with low current and high breaking capacity according to claim 1, characterized in that: The step of fitting the support portion to the cavity portion includes: Provide an adhesive material layer and perform graphical processing on the adhesive material layer; The patterned adhesive material layer is placed at the contact portion between the support portion and the cavity portion, and the support portion and the cavity portion are bonded together by a pressing process.

6. The method for preparing a surface mount fuse with low current and high breaking capacity according to any one of claims 1 to 5, characterized in that: The preparation method further includes an electrode formation step, comprising: A first power through hole and a second power through hole are respectively provided at the left and right ends of the fuse body. The first power through hole and the second power through hole both penetrate the support part and the cavity part along the direction from the support part to the cavity part, and two electrodes are respectively formed by electroplating based on the first power through hole and the second power through hole. Alternatively, a first electrical blind hole and a second electrical blind hole are provided at the left and right ends of the support portion. The first electrical blind hole and the second electrical blind hole penetrate the support portion along the direction from the support portion to the cavity portion until they contact the fuse unit. Two electrodes are formed by electroplating based on the first electrical blind hole and the second electrical blind hole. Alternatively, a third electrical blind hole and a fourth electrical blind hole are provided at the left and right ends of the cavity. The third electrical blind hole and the fourth electrical blind hole penetrate the cavity in the direction from the cavity to the support until they contact the fuse unit. Two electrodes are formed by electroplating based on the third electrical blind hole and the fourth electrical blind hole. Alternatively, a first side electrode and a second side electrode are provided on the left and right end faces of the cavity; a first end electrode is prepared on the surface of the first side electrode to electrically connect the first end electrode to the first end of the fuse unit through the first side electrode; a second end electrode is prepared on the surface of the second side electrode to electrically connect the second end of the fuse unit through the second side electrode; the first end electrode and the second end electrode cover the left and right end faces of the cavity.

7. A surface mount fuse with low current and high breaking capacity, characterized in that, The surface mount fuse with low current and high breaking capacity includes at least: a support portion and a cavity portion; The support portion and the cavity portion are fitted together to form the fuse body portion. The cavity portion has a machined groove on the side near the support portion to fit with the support portion to form a cavity. The support portion includes a fusible element, which is disposed in close contact with the surface of the support portion near the cavity portion to increase the mechanical stress of the fusible element, and the fusible element is disposed in the cavity; The surface mount fuse with low current and high breaking capacity also includes two electrodes; each electrode is respectively disposed at the left and right ends of the fuse body and is electrically connected to the two ends of the fusing unit. When the fuse unit only forms the body portion, the fuse unit is electrically connected to the corresponding electrode through the body portion; when the fuse unit also forms a connection structure, the fuse unit is electrically connected to the corresponding electrode through the connection structure.

8. The surface mount fuse with low current and high breaking capacity according to claim 7, characterized in that: The fusing unit is configured as a rectangular metal film or a serpentine metal film.

9. The surface mount fuse with low current and high breaking capacity according to claim 7, characterized in that: The surface mount fuse with low current and high breaking capacity also includes a bonding portion; the bonding portion is disposed between the support portion and the cavity portion, and is used to bond and connect the support portion and the cavity portion.

10. The surface mount fuse with low current and high breaking capacity according to claim 7, characterized in that: The two electrodes include a first power through hole and a second power through hole respectively provided at the left and right ends of the fuse body portion; the first power through hole and the second power through hole both penetrate the support portion and the cavity portion along the direction from the support portion to the cavity portion; the two electrodes also include two electroplated layer structures respectively prepared by electroplating along the surfaces of the first power through hole and the second power through hole; Alternatively, the two electrodes include a first electrical blind hole and a second electrical blind hole provided at the left and right ends of the support portion; the first electrical blind hole and the second electrical blind hole both penetrate the support portion along the direction of the support portion pointing to the cavity portion until they contact the fuse unit; the two electrodes also include two electroplated layer structures prepared by electroplating along the surfaces of the first electrical blind hole and the second electrical blind hole respectively. Alternatively, the two electrodes include a third electrical blind hole and a fourth electrical blind hole at the left and right ends of the cavity; the third electrical blind hole and the fourth electrical blind hole both penetrate the cavity in the direction from the cavity to the support until they contact the fuse unit; the two electrodes also include two electroplated layer structures prepared by electroplating along the surfaces based on the third electrical blind hole and the fourth electrical blind hole respectively; Alternatively, the two electrodes include a first side electrode and a second side electrode provided on the left and right end faces of the cavity; the two electrodes also include a first end electrode prepared on the surface of the first side electrode and a second end electrode prepared on the surface of the second side electrode; the first end electrode is electrically connected to the first end of the fuse unit through the first side electrode, and the second end electrode is electrically connected to the second end of the fuse unit through the second side electrode; the first end electrode and the second end electrode cover the left and right end faces of the cavity.

11. The surface mount fuse with low current and high breaking capacity according to claim 10, characterized in that: The fuse unit includes a body part and a connecting structure. The connecting structure is disposed at both ends of the body part and extends outward from both ends to connect to the corresponding electrodes. The width of the connecting structure is greater than the width of the body part.

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