Coil array

Abstract

To provide a coil array capable of adjusting a coupling coefficient.SOLUTION: In a coil array 1, both insulating substrates 14 of coils 13 of a pair of adjacent coil components 10 are biased to approach each other, thereby shortening a distance d between planar coil patterns 15 formed on the main surfaces 14a, 14b of the insulating substrate 14. The design of the distance d between the planar coil patterns 15 of a pair of adjacent coil components 10 can be appropriately changed by adjusting the thickness of the magnetic material constituting a base body 11, thereby allowing adjustment to a desired coupling coefficient.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to coil arrays. [Background technology]

[0002] The following cited document 1 discloses a coil component in which a first coil and a second coil overlap with a substrate interposed therebetween, and the coupling coefficient is increased by placing the substrate in the space between the first coil and the second coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-137421 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors conducted extensive research into the coupling coefficient between coils and discovered a new technique for adjusting the coupling coefficient.

[0005] An object of one aspect of the present disclosure is to provide a coil array capable of adjusting a coupling coefficient. [Means for solving the problem]

[0006] A coil array according to one aspect of the present disclosure comprises a base body containing metal magnetic powder, a plurality of coil components including a substrate provided within the base body and perpendicular to a first direction, a coil including a planar coil pattern formed on a main surface of the substrate, and a pair of external terminals provided on a surface of the base body and electrically connected to the coil, wherein the plurality of coil components are arranged along the first direction, and at least one of the substrates of a pair of coil components adjacent to each other in the first direction is biased toward the other substrate.

[0007] In the coil array, at least one of the substrates of a pair of adjacent coil components is biased toward the other substrate, thereby bringing the planar coil patterns formed on the main surfaces of the substrates closer together. The distance between the planar coil patterns of a pair of adjacent coil components can be appropriately changed in design, thereby allowing the coupling coefficient to be adjusted as desired. Effect of the Invention

[0008] According to various aspects of the present disclosure, a coil array is provided that has an adjustable coupling coefficient. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic perspective view showing a coil array according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the coil array shown in FIG. [Diagram 3] FIG. 3 is a diagram showing the internal structure of the coil component of FIGS. [Figure 4] FIG. 4 is a cross-sectional view of the coil device shown in FIG. 3 taken along line IV-IV. [Diagram 5] FIG. 5 is a cross-sectional view of the coil device shown in FIG. 3 taken along line VV. [Figure 6] FIG. 6 is a diagram showing the positional relationship between the coils of both coil components. [Figure 7] FIG. 7 is a table showing the test results. [Figure 8] FIG. 8 is a graph showing the test results. [Figure 9] FIG. 9 is a schematic perspective view showing a coil array according to a different embodiment. [Figure 10] FIG. 10 is a schematic perspective view showing a coil array according to a different embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Various embodiments and examples will be described below with reference to the drawings. Note that the same or corresponding parts in each drawing are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0011] A coil array 1 according to one embodiment has the configuration shown in Figs. 1 and 2. The coil array 1 is mounted (for example, solder mounted) on a mounting board 100 described later. The coil array 1 is applied, for example, to an in-vehicle device that requires a large current. The coil array 1 is configured to include a plurality of coil components 10, and in this embodiment, is configured to include two coil components 10. Hereinafter, the two coil components 10 will be appropriately referred to as a first coil component 10A and a second coil component 10B.

[0012] Each coil component 10 has a substantially rectangular parallelepiped outer shape and is substantially rectangular when viewed in the height direction. As an example, each coil component 10 may be designed with dimensions of a short side of 1.0 mm, a long side of 2.5 mm, and a height of 2.0 mm. Hereinafter, for convenience of explanation, the short side direction of the coil component 10 is also referred to as the first direction, the short side direction of the coil component 10 is also referred to as the first direction D1, the long side direction is also referred to as the second direction D2, and the height direction is also referred to as the third direction D3. The first direction D1, the second direction D2, and the third direction D3 are mutually perpendicular.

[0013] Each coil component 10 is configured to include an element body 11, a pair of external terminals 12A, 12B provided on the surface of the element body 11, and a coil 13 provided within the element body 11.

[0014] The element body 11 is made of a magnetic material. In this embodiment, the element body 11 is made of a resin containing a metal magnetic powder, which is a type of magnetic material. The resin containing a metal magnetic powder is a binding powder in which a metal magnetic powder is bound by a binder resin. The metal magnetic powder may be made of, for example, an iron-nickel alloy (permalloy alloy), carbonyl iron, an amorphous, non-crystalline or crystalline FeSiCr-based alloy, sendust, or the like. The binder resin is, for example, a thermosetting epoxy resin. In this embodiment, the content of the metal magnetic powder in the binding powder is 80 to 92 vol% in volume percent and 95 to 99 wt% in mass percent. From the viewpoint of magnetic properties, the content of the metal magnetic powder in the binding powder may be 85 to 92 vol% in volume percent and 97 to 99 wt% in mass percent.

[0015] The element body 11 has a substantially rectangular parallelepiped outer shape and has six faces 11a to 11f. Of the faces 11a to 11f of the element body 11, the upper face 11a and the lower face 11b face each other in the third direction D3, the end face 11c and the end face 11d face each other in the second direction D2, and the side face 11e and the side face 11f face each other in the first direction D1. The upper face 11a and the lower face 11b are parallel to each other, the end face 11c and the end face 11d are parallel to each other, and the side face 11e and the side face 11f are parallel to each other. The lower face 11b of the element body 11 is a face facing a mounting board 100 on which the coil array 1 is mounted.

[0016] 3 to 5 is provided within element body 11. Coil 13 according to this embodiment includes an insulating substrate 14, a first coil portion 17A, and a second coil portion 17B.

[0017] The insulating substrate 14 is a plate-like member made of a non-magnetic insulating material, and extends perpendicular to the first direction D1. The insulating substrate 14 has a substantially elliptical annular shape when viewed from the first direction D1. An elliptical through hole 14c is provided in the center of the insulating substrate 14. The insulating substrate 14 may be a substrate made of glass cloth impregnated with epoxy resin and having a thickness of 10 μm to 60 μm. In addition to epoxy resin, BT resin, polyimide, aramid, etc. may also be used. The insulating substrate 14 may be made of ceramic or glass. The insulating substrate 14 is preferably made of a mass-produced printed circuit board material, and is most preferably made of a resin material used for a BT printed circuit board, an FR4 printed circuit board, or an FR5 printed circuit board.

[0018] The first coil portion 17A is configured to include a planar coil pattern 15 provided on one surface 14a (surface on the side of the side surface 11f) of the insulating substrate 14, and resin walls 16 located between the lines of the planar coil pattern 15, and on the inner and outer periphery. The planar coil pattern 15 is formed by plating with a conductive material such as Cu. The planar coil pattern 15 is formed so as to be wound around the through hole 14c of the insulating substrate 14. The outer peripheral end 15a of the planar coil pattern 15 reaches the end surface 11c of the element body 11 and is exposed from the end surface 11c, and the inner peripheral end 15b terminates at the edge of the through hole 14c of the insulating substrate 14. The resin walls 16 are configured of an insulating resin material. The resin walls 16 can be provided on the insulating substrate 14 before the planar coil pattern 15 is formed, and in this case, the planar coil pattern 15 is plated and grown between the walls defined by the resin walls 16. That is, the resin walls 16 provided on the insulating substrate 14 define the formation area of ​​the planar coil pattern 15. The resin wall 16 can be provided on the insulating substrate 14 after the planar coil pattern 15 is formed. In this case, the resin wall 16 is provided on the planar coil pattern 15 by filling or coating.

[0019] The second coil portion 17B is configured to include a planar coil pattern 15 provided on the other surface 14b (surface on the side of the side 11e) of the insulating substrate 14, and resin walls 16 located between the lines of the planar coil pattern 15, and on the inner and outer periphery. The planar coil pattern 15 of the second coil portion 17B is also formed by plating with a conductive material such as Cu, similar to the planar coil pattern 15 of the first coil portion 17A. The planar coil pattern 15 of the second coil portion 17B is also formed to be wound around the through hole 14c of the insulating substrate 14, similar to the planar coil pattern 15 of the first coil portion 17A. The outer peripheral end 15a of the planar coil pattern 15 of the second coil portion 17B reaches the end surface 11d of the element body 11 and is exposed from the end surface 11d, and the inner peripheral end 15b terminates at the edge of the through hole 14c of the insulating substrate 14 (more specifically, at a position overlapping the inner peripheral end 15b of the planar coil pattern 15 of the first coil portion 17A in the first direction D1). Like the resin wall 16 of the first coil portion 17A, the resin wall 16 of the second coil portion 17B is also made of an insulating resin material.

[0020] In the first coil portion 17A and the second coil portion 17B, the resin walls 16 located on the inner and outer periphery of the planar coil pattern 15 can be designed to be thicker than the resin walls 16 located between the lines of the planar coil pattern 15.

[0021] In the first coil portion 17A and the second coil portion 17B, the surface of the planar coil pattern 15 exposed from the resin wall 16 is covered with an insulating layer 18. The insulating layer 18 is provided over the entire upper surface of the planar coil pattern 15 between adjacent resin walls 16. The insulating layer 18 is made of a resin such as an epoxy resin or a polyimide resin. The insulating layer 18 may be an electrodeposition layer formed using an electrodeposition method, in which case it has a uniform thickness.

[0022] An inner peripheral end 15b of the planar coil pattern 15 of the first coil portion 17A and an inner peripheral end 15b of the planar coil pattern 15 of the second coil portion 17B are connected via a through-hole conductor 19 that penetrates the edge of a through-hole 14c of the insulating substrate 14. The through-hole conductor 19 may be composed of a hole provided in the insulating substrate 14 and a conductive material (e.g., a metal material such as Cu) filled in the hole.

[0023] As shown in Figures 4 and 5, the magnetic material constituting element body 11 integrally covers coil 13. More specifically, the magnetic material constituting element body 11 covers coil 13 from above and below, and also covers the outer periphery of coil 13. The magnetic material constituting element body 11 also fills the inner region of coil 13. The magnetic material constituting element body 11 can be formed by molding so as to cover coil 13. The dimension (thickness) of element body 11 in the first direction D1 can be easily and freely adjusted by polishing the magnetic material after molding.

[0024] In the first coil component 10A shown in FIG. 3, the coil 13 is biased upward (toward the side surface 11f) as a whole. That is, the coil 13 of the first coil component 10A is offset toward the side surface 11f from the intermediate position Y of the element body 11 in the first direction D1. On the other hand, in the second coil component 10B, the coil 13 is biased downward (toward the side surface 11e) as a whole. That is, the coil 13 of the second coil component 10B is offset toward the side surface 11e from the intermediate position Y of the element body 11 in the first direction D1. As a result, as shown in FIG. 6, the coils 13 of the coil components 10 approach each other. At this time, the insulating substrate 14 of the coil 13 of the first coil component 10A is offset toward the side surface 11f from the intermediate position Y of the element body 11 in the first direction D1, and the insulating substrate 14 of the coil 13 of the second coil component 10B is offset toward the side surface 11e from the intermediate position Y of the element body 11 in the first direction D1. In this embodiment, the offset length L of the insulating substrate 14 of the coil 13 of the first coil component 10A is the same as the offset length L of the insulating substrate 14 of the coil 13 of the second coil component 10B. The planar coil pattern 15 of the coil 13 of the first coil component 10A and the planar coil pattern 15 of the coil 13 of the second coil component 10B are separated by a distance d in the first direction D1.

[0025] Of the pair of external terminals 12A and 12B, the external terminal 12A is provided on the end surface 11c side of the element body 11, and the external terminal 12B is provided on the end surface 11d side of the element body 11. The external terminal 12A integrally covers the end surface 11c and the upper surface 11a, lower surface 11b, side surface 11e, and side surface 11f near the end surface 11c, and is connected to the outer peripheral end 15a of the planar coil pattern 15 of the first coil part 17A exposed from the end surface 11c. The external terminal 12A integrally covers the end surface 11d and the upper surface 11a, lower surface 11b, side surface 11e, and side surface 11f near the end surface 11d, and is connected to the outer peripheral end 15a of the planar coil pattern 15 of the second coil part 17B exposed from the end surface 11d.

[0026] 1, in the coil array 1, the two coil components 10 are arranged along the first direction D1 with the side surfaces 11e, 11f of the body 11 facing each other. More specifically, the side surface 11f of the body 11 of the first coil component 10A and the side surface 11e of the body 11 of the second coil component 10B face each other in the first direction D1. Therefore, the coils 13 provided in the body 11 of the coil components 10 have a common coil axis X extending in the first direction D1.

[0027] In the coil array 1 according to this embodiment, an adhesive layer 30 is interposed between two coil components 10. The adhesive layer 30 has approximately the same dimensions as the side surface 11f of the element body 11 of the first coil component 10A, and covers the entire surface of the side surface 11f of the element body 11 of the first coil component 10A and covers the entire surface of the side surface 11e of the element body 11 of the second coil component 10B. The adhesive layer 30 is made of polyethylene, as an example. The adhesive layer 30 may be made of a non-magnetic material or a magnetic material.

[0028] The coil array 1 has two coil components 10 connected in parallel. In this embodiment, the two coil components 10 are connected in parallel by a pair of metal plates 20. Hereinafter, the pair of metal plates 20 will be appropriately referred to as a first metal plate 20A and a second metal plate 20B. As an example, each metal plate 20 can be made of pure copper (more specifically, tough pitch copper), and the surface may be Ni / Sn plated.

[0029] The first metal plate 20A is located on the end face 11c side of the element body 11 of each coil component 10, and covers the external terminal 12A that covers the end face 11c. The first metal plate 20A has a size that is approximately twice the end face 11c, and integrally covers and electrically connects the external terminal 12A of the first coil component 10A and the external terminal 12A of the second coil component 10B. Similarly, the second metal plate 20B is located on the end face 11d side of the element body 11 of each coil component 10, and covers the external terminal 12B that covers the end face 11d. The second metal plate 20B, like the first metal plate 20A, has a size that is approximately twice the end face 11d, and integrally covers and electrically connects the external terminal 12B of the first coil component 10A and the external terminal 12B of the second coil component 10B. Each metal plate 20 may be attached to the external terminals 12A and 12B using a conductive adhesive.

[0030] As described above, in the above-mentioned coil array 1, both insulating substrates 14 of the coils 13 of a pair of adjacent coil components 10 are biased to approach each other, thereby shortening the distance between the planar coil patterns 15 formed on the main surfaces 14a, 14b of the insulating substrate 14. The distance between the planar coil patterns 15 of a pair of adjacent coil components 10 can be appropriately designed and changed by adjusting the thickness of the magnetic material constituting the base body 11, and thereby the coupling coefficient can be adjusted to a desired value.

[0031] In order to confirm the relationship between the bias of the insulating substrate 14 and the coupling coefficient, the inventors performed a simulation analysis using a 3D model simulating the following embodiment. For this simulation analysis, ANSYS Electronics Desktop Maxwell 2021R1 simulation software manufactured by ANSYS was used. For each of the simulation models 1 to 5, a coil array was used in which a pair of coil components having dimensions in the first direction D1, such as a 900 μm thick element, a 60 μm thick substrate, a 200 μm high planar coil pattern, and a 225 μm high resin wall, were adjacent to each other. The same material having the same magnetic permeability was used as the magnetic material constituting the element of each of the simulation models 1 to 5. In addition, the coil components were bonded together using a 20 μm thick adhesive layer made of a resin material. In each of the simulation models 1 to 5, the offset length L of the substrate of both coil components was the same.

[0032] 7 and 8. That is, in simulation model 1 which is not offset from the middle position Y of the element body in the first direction D1, the coupling coefficient was 0.061, in simulation model 2 which is offset 50 μm toward the side from the middle position Y of the element body, the coupling coefficient was 0.076, in simulation model 3 which is offset 100 μm toward the side from the middle position Y of the element body, the coupling coefficient was 0.104, in simulation model 4 which is offset 150 μm toward the side from the middle position Y of the element body, the coupling coefficient was 0.175, and in simulation model 5 which is offset 195 μm toward the side from the middle position Y of the element body, the coupling coefficient was 0.607.

[0033] In this way, it was confirmed that the coupling coefficient changes when the offset length L of the substrate and the distance d between the coil patterns are changed. Therefore, the coupling coefficient can be appropriately adjusted by adjusting the offset length L of the substrate and the distance d between the coil patterns, for example by adjusting the thickness of the magnetic material constituting the element body. It was also confirmed that the longer the offset length L of the substrate, the higher the coupling coefficient. For example, as in simulation models 4 and 5, when the offset length L is 150 μm or more and the distance d between the coil patterns is 160 μm or less, a relatively high coupling coefficient of 0.150 or more can be obtained.

[0034] The present invention is not limited to the above-described embodiment, and can be modified in various ways. For example, the pair of adjacent coil components is not necessarily limited to a configuration in which both substrates are biased, and only one of the substrates may be biased. Furthermore, when both substrates of a pair of adjacent coil components are biased, the offset length L of both substrates may be the same or different.

[0035] In addition, the coil array is not limited to a coil array in which a plurality of coil components are connected in parallel, but may be a coil array in which a plurality of coil components are connected in series. FIG. 9 shows a coil array 1A in which two coil components 10 are connected in series. The coil array 1A is a three-terminal type and includes three metal plates 20. Of the three metal plates 20, the first metal plate 20A covers only the external terminal 12A that covers the end surface 11c of the first coil component 10A, the second metal plate 20B integrally covers the external terminal 12B that covers the end surface 11d of the first coil component 10A and the second coil component 10B, and the third metal plate 20C covers only the external terminal 12A that covers the end surface 11c of the first coil component 10B. In the coil array 1A, a voltage can be applied between the first metal plate 20A and the third metal plate 20C.

[0036] Furthermore, the number of coil components 10 in the coil array 1 is not limited to two, and can be increased as appropriate. FIG. 10 shows a coil array 1B including four coil components 10A to 10D. The dimensions of the metal plate 20 can be extended as appropriate according to the number of coil components 10. The adhesive layer 30 can be interposed between each of the coil components 10 adjacent to each other in the first direction D1. In the coil array 1B, a current that is approximately four times larger than that in the case where the coil component 10 is used alone can be passed, and the direct current resistance can be reduced to approximately one-quarter. In the coil array 1B, the insulating substrates 14 of some of the coil components 10 among the four coil components 10A to 10D are offset. Specifically, only the insulating substrate 14 of the coil 13 of the coil component 10B is offset. In the coil array 1B, the direction of magnetic flux generated in the coils 13 of the coil components 10A to 10D when a voltage is applied between a pair of metal plates 20 may be the same, or the direction of some of the coil components 10 (for example, only the coil component 10D) may be reversed so that the direction of magnetic flux generated in the coil 13 is opposite to that of the others. In this case, interference of coil magnetic flux may occur between the adjacent coil components 10C and 10D.

[0037] The coil is not limited to an elliptical ring shape, but may be, for example, a circular ring shape, a rectangular ring shape, etc. Furthermore, the number of turns of the coil can be increased or decreased as appropriate.

[0038] As can be understood from the above description, the present specification discloses the following. [Appendix 1] a plurality of coil components each including an element body containing a metal magnetic powder, a substrate provided in the element body and perpendicular to a first direction, a coil including a planar coil pattern formed on a main surface of the substrate, and a pair of external terminals provided on a surface of the element body and electrically connected to the coil; A coil array in which the multiple coil components are aligned along the first direction, and at least one substrate of a pair of coil components adjacent to each other in the first direction is biased toward the other substrate. [Appendix 2] 2. The coil array of claim 1, wherein the multiple coil components are connected in parallel. [Appendix 3] 3. The coil array of claim 1, wherein the substrates of both of a pair of coil components adjacent to each other in the first direction are biased to approach each other. [Appendix 4] 4. The coil array of claim 3, wherein the substrates of both of a pair of adjacent coil components in the first direction are offset by the same distance. [Appendix 5] 2. The coil array of claim 1, wherein the plurality of coil components are connected in series. [Appendix 6] 6. The coil array according to claim 1, wherein an element of each of the coil components has a mounting surface facing a mounting board, and the first direction extends parallel to the mounting surface. [Appendix 7] 7. The coil array according to claim 1, further comprising an adhesive layer interposed between the coil components adjacent to each other in the first direction. [Appendix 8] 8. The coil array of claim 7, wherein the distance between the planar coil patterns of a pair of adjacent coil components in the first direction is 160 μm or less. [Explanation of symbols]

[0039] 1, 1A, 1B... coil array, 10, 10A to 10D... coil component, 11... element body, 11a... upper surface, 11b... lower surface, 11c, 11d... end surface, 11e, 11f... side surface, 12A, 12B... external terminal, 13... coil, 14... insulating substrate, 20, 20A to 20C... metal plate, 30... adhesive layer, D1... first direction, D2... second direction, D3... third direction.

Claims

1. a coil component including an element body containing a metal magnetic powder, a substrate provided in the element body and perpendicular to a first direction, a coil including a planar coil pattern formed on a main surface of the substrate, and a pair of external terminals provided on a surface of the element body and electrically connected to the coil; A coil array in which the multiple coil components are aligned along the first direction, and at least one substrate of a pair of coil components adjacent to each other in the first direction is biased toward the other substrate.

2. The coil array of claim 1 , wherein the plurality of coil components are connected in parallel.

3. The coil array according to claim 1 , wherein both substrates of a pair of coil components adjacent to each other in the first direction are biased to approach each other.

4. The coil array according to claim 3 , wherein the substrates of both of a pair of adjacent coil components in the first direction are offset by the same distance.

5. The coil array of claim 1 , wherein the plurality of coil components are connected in series.

6. The coil array according to claim 1 , wherein an element of each of the coil components has a mounting surface facing a mounting board, and the first direction extends parallel to the mounting surface.

7. The coil array according to claim 1 , further comprising an adhesive layer interposed between adjacent ones of the coil components in the first direction.

8. The coil array according to claim 7 , wherein the distance between the planar coil patterns of a pair of adjacent coil components in the first direction is 160 μm or less.

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