Inductor and manufacturing method thereof

Abstract

The invention discloses an inductor and a manufacturing method thereof. The inductor comprises at least two inductance structures, and each inductance structure comprises a single coil, a magnetic body, an electrode structure and a protection structure. The single coil has a first end portion and a second end portion. The magnetic body covers the single coil, and the first end portion and the second end portion are exposed from the bottom surface of the magnetic body. The electrode structure is arranged on the bottom surface of the magnetic body, the electrode structure comprises a first electrode and a second electrode which are arranged at an interval, the first electrode is electrically connected with the first end part, and the second electrode is electrically connected with the second end part. The protection structure is arranged on the bottom surface of the magnetic body and separates the first electrode from the second electrode.

Description

Technical Field

[0001] The present application relates to an inductor and a method for manufacturing the same, and in particular to an inductor with good reliability and a method for manufacturing the same. Background Art

[0002] An inductor is a circuit component that generates an electromotive force due to a change in the current passing through it, thereby resisting the change in current. Depending on the configuration of different structures, inductors can have different inductance values ​​to meet various characteristic requirements.

[0003] However, if different characteristics are required each time, the structure must be redesigned, which will incur a lot of time and design costs. Therefore, how to improve the convenience of inductor configuration through structural design improvements has become one of the important issues that this business wants to solve. Summary of the invention

[0004] The technical problem to be solved by the present application is to provide an inductor and a manufacturing method thereof in view of the deficiencies in the prior art.

[0005] In order to solve the above-mentioned technical problems, one of the technical solutions adopted by the present invention is to provide an inductor. The inductor includes at least two inductance structures, each of which includes: a single coil, a magnetic body, an electrode structure and a protective structure. The single coil has a first end and a second end. The magnetic body covers the single coil, and the first end and the second end are exposed from the bottom surface of the magnetic body. The electrode structure is arranged on the bottom surface of the magnetic body, and the electrode structure includes a first electrode and a second electrode arranged at intervals, the first electrode is electrically connected to the first end, and the second electrode is electrically connected to the second end. The protective structure is arranged on the bottom surface of the magnetic body, and the protective structure separates the first electrode and the second electrode.

[0006] Furthermore, there is a gap between the first electrode and the second electrode, and the gap is greater than or equal to 0.1 mm.

[0007] Furthermore, the first end and the second end of the single coil extend toward each other but do not contact each other.

[0008] Furthermore, the first end and the second end of the single coil extend in opposite directions but do not contact each other.

[0009] Furthermore, relative to the bottom surface, the thickness of the electrode structure is greater than the thickness of the protection structure.

[0010] Furthermore, the protection structure and the electrode structure jointly cover the outer surface of the magnetic body.

[0011] Furthermore, the first electrode has a first side electrode extending from the bottom surface to one side surface of the magnetic body; the second electrode has a second side electrode extending from the bottom surface to the other side surface of the magnetic body.

[0012] Furthermore, relative to the bottom surface, an extended height of the first side electrode is greater than or equal to 0.01 mm, and an extended height of the second side electrode is greater than or equal to 0.01 mm.

[0013] Furthermore, relative to the bottom surface, the extension height of the first side electrode is lower than or equal to the height of the magnetic body, and the extension height of the second side electrode is lower than or equal to the height of the magnetic body.

[0014] Furthermore, the material of the protection structure includes epoxy resin, acrylic resin or silicone.

[0015] Furthermore, an adhesive layer is disposed between two adjacent inductor structures.

[0016] Furthermore, the material of the adhesive layer is epoxy resin, acrylic resin or silicone.

[0017] Furthermore, the material of the magnetic body includes at least one of crystalline metal magnetic powder and amorphous metal magnetic powder.

[0018] Furthermore, the crystalline metal magnetic powder is selected from the group consisting of: iron-silicon alloy powder, iron-silicon-chromium alloy powder, iron-silicon-aluminum alloy powder, iron-nickel alloy powder, carbonyl iron powder, iron powder, iron-nickel-molybdenum alloy powder and iron-cobalt-vanadium alloy powder.

[0019] Furthermore, the amorphous metal magnetic powder is selected from the group consisting of: iron silicon boron carbon powder and iron silicon chromium boron phosphorus carbon powder.

[0020] In order to solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a method for manufacturing an inductor. The method for manufacturing an inductor includes the following steps: a single coil is prepared, and the single coil has a first end and a second end. A molding process is performed to bury the single coil in a magnetic body, and the first end and the second end are exposed from a bottom surface of the magnetic body. A protective structure is set on the bottom surface. A portion of the protective structure is removed so that the first end and the second end are exposed from the bottom surface. An electroplating process is performed to form an electrode structure on the bottom surface of the magnetic body; wherein the electrode structure includes a first electrode and a second electrode arranged at intervals, the first electrode is electrically connected to the first end, the second electrode is electrically connected to the second end, and the protective structure separates the first electrode and the second electrode. Two adjacent electrode structures are fixed with an adhesive layer to obtain an inductor.

[0021] Furthermore, there is a gap between the first electrode and the second electrode, and the gap is greater than or equal to 0.1 mm.

[0022] In order to solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide an inductor. The inductor includes an inductor structure, which includes: a single coil, a magnetic body, an electrode structure and a protective structure. The single coil has a first end and a second end. The magnetic body covers the single coil, and the first end and the second end are exposed from the bottom surface of the magnetic body. The electrode structure is arranged on the bottom surface of the magnetic body, and the electrode structure includes a first electrode and a second electrode arranged at intervals, the first electrode is electrically connected to the first end, and the second electrode is electrically connected to the second end. The protective structure is arranged on the bottom surface of the magnetic body, and the protective structure separates the first electrode and the second electrode.

[0023] One of the beneficial effects of the present invention is that the inductor and the manufacturing method thereof provided by the present invention can provide an inductor structure with good reliability through the technical solutions of "the electrode structure includes a first electrode and a second electrode arranged at intervals" and "the protection structure separates the first electrode and the second electrode", and inductors with different inductance values ​​can be obtained by free combination.

[0024] To further understand the features and technical contents of the present application, please refer to the following detailed description and drawings of the present application. However, the drawings provided are only for reference and illustration and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. 4 is a schematic three-dimensional diagram of an inductor according to a first embodiment of the present invention.

[0026] Figure 2 FIG. 4 is a schematic side view of an inductor according to a first embodiment of the present invention.

[0027] Figures 3 to 7 FIG. 4 is a schematic side view of the inductor structure during the manufacturing process of the first embodiment of the present invention from another angle.

[0028] Figure 8 for Figure 7 Bottom view of the inductor structure.

[0029] Fig. 9 FIG. 4 is a schematic side view of an inductor structure from another angle in one embodiment of the present invention.

[0030] Fig.10 FIG. 4 is a schematic side view of an inductor structure at another angle in another embodiment of the present invention.

[0031] Fig.11 FIG. 4 is a schematic side view of an inductor structure from another angle in yet another embodiment of the present invention.

[0032] Fig.12 FIG. 4 is a schematic three-dimensional diagram of an inductor according to a second embodiment of the present invention.

[0033] Fig.13 FIG. 4 is a three-dimensional schematic diagram of an inductor according to a third embodiment of the present invention.

[0034] Fig.14 FIG. 4 is a three-dimensional schematic diagram of an inductor according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following is an explanation of the implementation of the "inductor" disclosed in the present invention through specific examples. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following implementations will further explain the relevant technical contents of the present invention in detail, but the disclosed contents are not intended to limit the scope of protection of the present invention. In addition, the term "or" used in this article may include any one or more combinations of the associated listed items depending on the actual situation.

[0036] The present invention provides an inductor, which includes an inductor structure. The inductor structure has a protection structure, which separates two adjacent electrodes, so that the inductor has good reliability. In addition, the inductor structure of the present invention can be freely combined to obtain inductors with different inductance values.

[0037] Please refer to the combined Figure 1 and Figure 2 As shown, the present invention provides an inductor, which may include at least two inductor structures 1. Two adjacent inductor structures 1 are arranged in parallel and fixed by an adhesive layer 5. The material of the adhesive layer 5 includes epoxy resin, acrylic resin or silicone. In an exemplary embodiment, the adhesive layer 5 may be formed by coating, but the present invention is not limited thereto.

[0038] Each inductor structure 1 can be regarded as a minimum structural unit. By combining multiple inductor structures 1, the inductance value of the inductor can be adjusted. Each inductor structure includes a single coil 10, a magnetic body 20, an electrode structure 30 and a protection structure 40.

[0039] Please refer to Figure 3 As shown, the single coil 10 is an open coil. A first end 101 and a second end 102 of the single coil 10 are not connected to form a closed loop, and an opening 100 is formed between the first end 101 and the second end 102 .

[0040] In an exemplary embodiment, two ends of a single coil 10 may be bent toward each other and extend to form a first end 101 and a second end 102, and the opening 100 is located between the first end 101 and the second end 102. Figure 3 shown.

[0041] In an exemplary embodiment, the two ends of the single coil 10 may also be bent in opposite directions and extend to form a first end 101 and a second end 102, such as Fig.10 It should be particularly noted that the first end portion 101 and the second end portion 102 will not protrude from the side surface of the magnetic body 20 , or be exposed from the side surface of the magnetic body 20 .

[0042] In other embodiments, the first end 101 and the second end 102 of the single coil 10 may also extend in the same direction without bending. Fig.11 The size of the single coil 10 can be adjusted according to the characteristic requirements. For example, by adjusting the distance between the first end 101 and the second end 102, the impedance value can be adjusted.

[0043] The single coil 10 is made of a single material and is not a coupled coil. Specifically, the inductive coupling coefficient of the inductor may be less than 0.9. Preferably, the inductive coupling coefficient of the inductor may be less than 0.5. More preferably, the inductive coupling coefficient of the inductor may be less than 0.3, even less than 0.1, or less than 0.08.

[0044] Figure 3 Although the appearance of the single coil 10 in the figure is square, the shape of the single coil 10 is not limited thereto and may also be circular, triangular or other polygonal. Figure 1 Although the cross section of the single coil 10 is rectangular, the cross section of the single coil 10 is not limited thereto, and may also be circular or other shapes.

[0045] Please refer to the combined Figure 2 and Figure 4 As shown, the magnetic body 20 covers the single coil 10. It should be particularly noted that on a bottom surface 200 of the magnetic body 20, the first end 101 and the second end 102 of the single coil 10 are flush with the bottom surface 200 of the magnetic body 20. In other words, a portion of the first end 101 and a portion of the second end 102 are exposed from the bottom surface 200 of the magnetic body 20. Figure 4 As shown, the single coil 10 can be electrically connected to an external circuit.

[0046] The material of the magnetic body 20 includes metal magnetic powder and adhesive component. The metal magnetic powder includes at least one of crystalline metal magnetic powder and amorphous metal magnetic powder. For example, the crystalline metal magnetic powder can be iron silicon alloy powder, iron silicon chromium alloy powder, iron silicon aluminum alloy powder, iron nickel alloy powder, carbonyl iron powder, iron powder, iron nickel molybdenum alloy powder or iron cobalt vanadium alloy powder. The amorphous metal magnetic powder can be iron silicon boron carbon powder or iron silicon chromium boron phosphorus carbon powder. The adhesive component can be epoxy resin, acrylic resin or silicone.

[0047] Since the material of the magnetic body 20 is a mixture of metal magnetic powder and adhesive components, the magnetic body 20 can be formed by a compression molding process. However, the present invention is not limited thereto.

[0048] Please refer to the combined Figure 1 , Figure 2 , Figure 7 and Figure 8 As shown, the electrode structure 30 is disposed on the bottom surface 200 of the magnetic body 20. The electrode structure 30 includes a first electrode 31 and a second electrode 32 that are spaced apart. The first electrode 31 is in contact with and electrically connected to the first end 101, and the second electrode 32 is in contact with and electrically connected to the second end 102. Accordingly, the single coil 10 can be electrically connected to an external circuit through the electrode structure 30.

[0049] See also Figure 7 As shown, relative to the bottom surface 200, the thickness of the electrode structure 30 may be higher than the thickness of the protection structure 40. Therefore, the electrode structure 30 may help the solder to be fixed during the subsequent soldering process.

[0050] See also Figure 8 As shown, in order to avoid short circuit, a gap D is provided between the first electrode 31 and the second electrode 32. Specifically, the gap D is greater than or equal to 0.1 mm.

[0051] See also Fig. 9 As shown, the electrode structure 30 is not only disposed on the bottom surface 200, but also can be extended to the side surface of the magnetic body 20 to form an L-shaped electrode structure. In this way, the electrode structure 30 can have a higher contact area with the solder and can have a better bonding effect.

[0052] Specifically, the first electrode 31 may include a first side electrode 311, which extends from the bottom surface 200 to one side surface of the magnetic body 20. The extension height of the first side electrode 311 is greater than or equal to 0.01 mm relative to the bottom surface 200. Similarly, the second electrode 32 may include a second side electrode 321, which extends from the bottom surface 200 to the other side surface of the magnetic body 20. The extension height of the second side electrode 321 is greater than or equal to 0.01 mm relative to the bottom surface 200.

[0053] The formation of the first side electrode 311 and the second side electrode 321 can enhance the bonding strength of the inductor on the printed circuit board (PCB). In the present invention, relative to the bottom surface 200, the extension height of the first side electrode 311 and the second side electrode 321 is lower than or equal to the height of the magnetic body 20. For example, the extension height of the first side electrode 311 and the second side electrode 321 can be 0.2, 0.4, 0.6, 0.8 or 1 times the height of the magnetic body 20, but the present invention is not limited thereto.

[0054] In an exemplary embodiment, the material of the electrode structure 30 may be at least one of copper, nickel, and tin. For example, the material of the electrode structure 30 may be a copper-nickel alloy, a tin-copper alloy, or a copper-nickel-tin alloy, or the electrode structure 30 may include a copper layer, a nickel layer, and a tin layer disposed in sequence, and the copper layer is in contact with the first end 101 or the second end 102.

[0055] Please refer to the combined Figure 7 , Figure 8 As shown, the protection structure 40 is disposed on the bottom surface 200 of the magnetic body 20, and the protection structure 40 is disposed between the first electrode 31 and the second electrode 32. That is, the protection structure 40 is disposed in the gap D.

[0056] The protection structure 40 can be used as a barrier wall between the first electrode 31 and the second electrode 32. During the electroplating process, metal cannot be deposited on the protection structure 40. Therefore, the provision of the protection structure 40 can prevent the first electrode 31 and the second electrode 32 from being connected.

[0057] At Figure 8 In the illustrated example, the protection structure 40 is in an H-shape on the bottom surface 200, so as to achieve the effect of separating the first electrode 31 from the second electrode 32. However, the shape of the protection structure 40 is not limited thereto.

[0058] See also Figure 7 As shown, in addition to the bottom surface 200, the protection structure 40 can also be disposed on other surfaces of the magnetic body 20. In this way, the protection structure 40 and the electrode structure 30 can cover the magnetic body 20 together to prevent the magnetic body 20 or the single coil 10 from contacting the outside.

[0059] The material of the protection structure 40 includes epoxy resin, acrylic resin or silicone. In an exemplary embodiment, the protection structure 40 may be formed by spraying. However, the present invention is not limited thereto.

[0060] [First embodiment]

[0061] Please refer to the combined Figures 1 to 8 As shown, the inductor according to the first embodiment of the present invention can be manufactured through the following steps.

[0062] In step S1, a single coil 10 with two ends not connected is prepared, such as Figure 3 The single coil 10 is placed in a mold with its opening 100 facing downward, so that the first end 101 and the second end 102 are in contact with the bottom of the mold.

[0063] In step S2, the material for forming the magnetic body 20 is prepared, filled into a mold, and covered on the single coil 10. Next, a compression molding process is performed to solidify the material to form the magnetic body 20, and the magnetic body 20 covers the single coil 10. Figure 4 shown.

[0064] Since the first end 101 and the second end 102 of the single coil 10 are in contact with the bottom of the mold, a portion of the first end 101 and a portion of the second end 102 are exposed from the bottom surface 200 of the magnetic body 20 after the molding process.

[0065] In step S3, a protective structure 40 is formed on the outer surface (including the bottom surface 200) of the magnetic body 20 through a spraying process. Figure 5 In other embodiments, the protection structure 40 may be formed only on the bottom surface 200 of the magnetic body 20 .

[0066] In step S4, a portion of the protection structure 40 is removed by laser or grinding, so that the first end 101 and the second end 102 are exposed from the bottom surface 200 of the magnetic body 20. Figure 6 It is worth noting that the protection structure 40 located between the first end portion 101 and the second end portion 102 needs to be retained to achieve the effect of separating the first end portion 101 from the second end portion 102 .

[0067] In step S5, an electroplating process is performed to form the electrode structure 30 on the bottom surface 200 of the magnetic body 20 to obtain the electrode structure 1. Since the protection structure 40 is non-conductive, the electrode structure 30 is not formed on the protection structure 40, but only on the magnetic body 20 and the first end 101 and the second end 102 exposed from the bottom surface 200.

[0068] In addition, according to different formation positions, the electrode structure 30 that contacts the first end 101 is called the first electrode 31, and the electrode structure 30 that contacts the second end 102 is called the second electrode 32. In addition, the first electrode 31 and the second electrode 32 are not in contact and are separated by a gap D, as shown in FIG. Figure 7 , Figure 8 shown.

[0069] In step S6, at least two electrode structures 1 are fixed with an adhesive layer 5 to obtain an inductor, such as Figure 2 Specifically, two electrode structures 1 are arranged in parallel.

[0070] In this specification, the parallel arrangement of the electrode structures 1 refers to the parallel arrangement of the single coils 10 in the electrode structures 1. In this way, when the current passing through the single coil 10 changes, the two electrode structures 1 will generate electromotive forces in the same direction. Therefore, by combining multiple electrode structures 1, the effect of adjusting the inductor characteristics can be achieved.

[0071] It is worth noting that the material of the adhesive layer 5 is similar to that of the protection structure 40 and has good compatibility. Therefore, when two adjacent electrode structures 1 are combined with the adhesive layer 5 , a good combination effect can be achieved.

[0072] The inductor of the present invention may be composed of a plurality of identical or different inductor structures. In the first embodiment, the inductor is composed of the same inductor structure (e.g. Figure 1 In the second to fourth embodiments, the inductor is composed of different inductor structures (such as Figures 12 to 14 shown).

[0073] See also Fig.12 As shown, in the inductor of the second embodiment, the inductor structure 1 and the inductor structure 6 have similar structures, and the difference between them is that the magnetic body 20A in the inductor structure 6 is different from the magnetic body 20 in the inductor structure 1 .

[0074] For example, the magnetic body 20A in the inductor structure 6 is composed of carbonyl iron metal magnetic powder and epoxy resin adhesive component. The magnetic body 20B in the inductor structure 1 is composed of iron-nickel alloy metal magnetic powder and epoxy resin adhesive component.

[0075] See also Fig.13 As shown, in the inductor of the third embodiment, the inductor structure 1 and the inductor structure 7 have similar structures, and the difference is that: the two ends of the single coil 10 in the inductor structure 1 are bent toward each other and extended to form a first end 101 and a second end 102; the two ends of the single coil 10 in the inductor structure 7 are bent away from each other and extended to form a first end 101 and a second end 102.

[0076] See also Fig.14 As shown, in the inductor of the fourth embodiment, the inductor structure 1 and the inductor structure 8 have similar structures, and the difference is that in the induced magnetic field direction of the single coil 10 , the thickness of the inductor structure 1 is thicker than the thickness of the inductor structure 8 .

[0077] [Beneficial Effects of Embodiments]

[0078] One of the beneficial effects of the present invention is that the inductor and the manufacturing method thereof provided by the present invention can provide an inductor structure with good reliability through the technical solutions of "the electrode structure includes a first electrode and a second electrode arranged at intervals" and "the protection structure separates the first electrode and the second electrode", and inductors with different inductance values ​​can be obtained by free combination.

[0079] The contents disclosed above are only preferred feasible embodiments of the present application, and are not intended to limit the protection scope of the claims of the present application. Therefore, all equivalent technical changes made using the contents of the present application specification and drawings are included in the protection scope of the claims of the present application.

Claims

1. An inductor, It is characterized in that The inductor comprises at least two inductor structures, each of which comprises: A single coil having a first end and a second end; a magnetic body covering the single coil, wherein the first end and the second end are exposed from a bottom surface of the magnetic body; an electrode structure disposed on the bottom surface of the magnetic body, wherein the electrode structure includes a first electrode and a second electrode disposed at intervals, the first electrode is electrically connected to the first end, and the second electrode is electrically connected to the second end; and A protection structure is disposed on the bottom surface of the magnetic body, and the protection structure separates the first electrode and the second electrode.

2. The inductor according to claim 1, It is characterized in that There is a gap between the first electrode and the second electrode, and the gap is greater than or equal to 0.1 mm.

3. The inductor according to claim 1, It is characterized in that The first end portion and the second end portion of the single coil extend toward each other but do not contact each other.

4. The inductor according to claim 1, It is characterized in that The first end and the second end of the single coil extend in opposite directions but do not contact each other.

5. The inductor according to claim 1, It is characterized in that Relative to the bottom surface, the thickness of the electrode structure is greater than the thickness of the protection structure.

6. The inductor according to claim 1, It is characterized in that The protection structure and the electrode structure jointly cover the outer surface of the magnetic body.

7. The inductor according to claim 1, It is characterized in that The first electrode has a first side electrode extending from the bottom surface to one side surface of the magnetic body; the second electrode has a second side electrode extending from the bottom surface to the other side surface of the magnetic body.

8. The inductor according to claim 7, It is characterized in that Relative to the bottom surface, an extended height of the first side electrode is greater than or equal to 0.01 mm, and an extended height of the second side electrode is greater than or equal to 0.01 mm.

9. The inductor according to claim 7, It is characterized in that With respect to the bottom surface, an extension height of the first side electrode is lower than or equal to a height of the magnetic body, and an extension height of the second side electrode is lower than or equal to a height of the magnetic body.

10. The inductor according to claim 1, It is characterized in that The material of the protection structure includes epoxy resin, acrylic resin or silicone.

11. The inductor according to claim 1, It is characterized in that An adhesive layer is disposed between two adjacent inductor structures.

12. The inductor according to claim 11, It is characterized in that The material of the adhesive layer is epoxy resin, acrylic resin or silica gel.

13. The inductor according to claim 1, It is characterized in that The material of the magnetic body includes at least one of crystalline metal magnetic powder and amorphous metal magnetic powder.

14. The inductor according to claim 13, It is characterized in that The crystalline metal magnetic powder is selected from the group consisting of: iron-silicon alloy powder, iron-silicon-chromium alloy powder, iron-silicon-aluminum alloy powder, iron-nickel alloy powder, carbonyl iron powder, iron powder, iron-nickel-molybdenum alloy powder and iron-cobalt-vanadium alloy powder.

15. The inductor according to claim 13, It is characterized in that The amorphous metal magnetic powder is selected from the group consisting of: iron silicon boron carbon powder and iron silicon chromium boron phosphorus carbon powder.

16. A method for manufacturing an inductor, It is characterized in that The manufacturing method comprises: A single coil is provided, wherein the single coil has a first end and a second end; Performing a molding process to embed the single coil in a magnetic body, with the first end and the second end exposed from a bottom surface of the magnetic body; A protective structure is provided on the bottom surface; Removing a portion of the protective structure so that the first end portion and the second end portion are exposed from the bottom surface; Performing an electroplating process to form an electrode structure on the bottom surface of the magnetic body; wherein the electrode structure includes a first electrode and a second electrode spaced apart, the first electrode is electrically connected to the first end, the second electrode is electrically connected to the second end, and the protection structure separates the first electrode from the second electrode; and The two adjacent electrode structures are fixed by an adhesive layer to obtain an inductor.

17. The manufacturing method according to claim 16, It is characterized in that There is a gap between the first electrode and the second electrode, and the gap is greater than or equal to 0.1 mm.

18. An inductor, It is characterized in that The inductor comprises an inductor structure, and the inductor structure comprises: A single coil having a first end and a second end; a magnetic body covering the single coil, wherein the first end and the second end are exposed from a bottom surface of the magnetic body; an electrode structure disposed on the bottom surface of the magnetic body, wherein the electrode structure includes a first electrode and a second electrode disposed at intervals, the first electrode is electrically connected to the first end, and the second electrode is electrically connected to the second end; and A protection structure is disposed on the bottom surface of the magnetic body, and the protection structure separates the first electrode and the second electrode.

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