Magnetic body and coil component provided with the same

Abstract

The present application provides a magnetic body capable of improving the electrical characteristics of a coil when used as a magnetic circuit by being disposed on the back of the coil, and a coil component provided with the magnetic body. A coil component (100) is provided with a magnetic body (10), and a coil (20) overlapping the magnetic body (10). The magnetic body (10) is provided with a first magnetic body layer (11), and a second magnetic body layer (12) laminated to the first magnetic body layer (11). The first magnetic body layer (11) is composed of a nanocrystalline alloy material, and the second magnetic body layer (12) is composed of a composite magnetic material in which magnetic powder F is mixed in resin R. The coil (20) is disposed opposite the second magnetic body layer (12) of the magnetic body (10).

Description

Technical Field

[0001] This disclosure relates to a magnetic body and a coil component having the magnetic body, and more particularly to a magnetic body comprising a nanocrystalline alloy material and a coil component having the magnetic body. Background Technology

[0002] Patent Document 1 discloses a wireless power transmission device with a magnetic element made of a nanocrystalline alloy material. Because the nanocrystalline alloy material has a very high relative permeability, it can achieve high magnetic saturation characteristics when used as a magnetic circuit by placing it on the back side of a coil.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-134959 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, because nanocrystalline alloy materials are conductive, they have the following problems: due to the influence of eddy currents, the resistance of the coil increases and the Q value of the coil decreases.

[0008] In this disclosure, a magnetic material that can improve the electrical characteristics of a coil when used as a magnetic circuit by being disposed on the back side of the coil, and a coil component having the magnetic material are described.

[0009] Technical solutions for solving technical problems

[0010] One aspect of this disclosure relates to a magnetic body comprising a first magnetic body layer and a second magnetic body layer stacked on the first magnetic body layer, wherein the first magnetic body layer is composed of a nanocrystalline alloy material and the second magnetic body layer is composed of a composite magnetic material in which magnetic powder is mixed in a resin.

[0011] One aspect of this disclosure relates to a coil component comprising the aforementioned magnetic body and a coil overlapping the magnetic body, wherein the coil and a second magnetic body layer of the magnetic body are disposed opposite to each other.

[0012] The effects of the invention

[0013] According to this disclosure, a magnetic body that can improve the electrical characteristics of a coil when used as a magnetic circuit by being disposed on the back side of the coil, and a coil component having the magnetic body can be provided. Attached Figure Description

[0014] Figure 1 This is a schematic diagram used to illustrate the basic structure of wireless power transmission devices.

[0015] Figure 2 This is a schematic top view illustrating the structure of a coil component 100, which is used to explain one embodiment of the technology disclosed herein.

[0016] Figure 3 (a) is along Figure 2 The approximate cross-sectional view of line AA shown. Figure 3 (b) is along Figure 2 A rough cross-sectional view of the BB line shown.

[0017] Figure 4 (a) to (c) are schematic cross-sectional views used to illustrate the structural changes of the coil component 100.

[0018] Figure 5 This is a schematic top view showing an example of the first magnetic layer 11 being composed of multiple nanocrystalline alloy tiles.

[0019] Explanation of reference numerals in the attached figures:

[0020] 10, 10A, 10B Magnetic materials

[0021] 11 First Magnetic Layer

[0022] 11A Slit

[0023] 12 Second Magnetic Layer

[0024] 13 Adhesive Layer

[0025] 14 Insulation layer

[0026] 15 Slits

[0027] 20 coils

[0028] 21 Peripheral end

[0029] 22 inner peripheral end

[0030] 23 Outermost edge

[0031] 24 Innermost peripheral edge

[0032] 30 Metal Sheets

[0033] 40 flexible substrate

[0034] 41, 42 wiring

[0035] Terminal electrodes 43 and 44

[0036] 50 solder

[0037] 100 and 200 coil components

[0038] 301 Power Supply Circuit

[0039] 302 Power receiving circuit

[0040] F magnetic powder

[0041] R resin Detailed Implementation

[0042] The following is a reference to the appendix. Figure 1 The embodiments of the technology disclosed herein will be described in detail below.

[0043] Figure 1 This is a schematic diagram used to illustrate the basic structure of wireless power transmission devices.

[0044] Figure 1 The wireless power transmission device shown includes a coil component 100 and a coil component 200. The coil component 100 includes a magnetic body 10 and a coil 20 disposed on its surface, and a power supply circuit 301 is connected to the coil 20. Thus, the coil component 100 and the power supply circuit 301 constitute a power supply device. The coil component 200 includes a magnetic body 10 and a coil 20 disposed on its surface, and a power receiving circuit 302 is connected to the coil 20. Thus, the coil component 200 and the power receiving circuit 302 constitute a power receiving device. The power supply device and the power receiving device are arranged with the coils 20 facing each other and separated by a predetermined space. In this state, when current flows from the power supply circuit 301 included in the power supply device to the coil 20, the resulting magnetic flux links with the coil 20 included in the power receiving device, supplying power to the power receiving circuit 302. The magnetic body 10 included in the coil components 100 and 200, by being disposed on the back side of the coil 20, serves as a magnetic circuit for the magnetic flux. Furthermore, when the surface of the coil 20 is covered with an insulating material, such as... Figure 1 In the example shown, coil 20 and magnet 10 can also be grounded. Alternatively, coil 20 can be positioned between it and magnet 10 via an insulating component.

[0045] The structures of coil component 100 and coil component 200 may be the same or different. Hereinafter, the structure of coil component 100 will be described in more detail.

[0046] Figure 2 This is a schematic top view illustrating the structure of a coil component 100 according to one embodiment of the technology disclosed herein. Additionally, Figure 3 (a) is along Figure 2 The approximate cross-sectional view of line AA shown. Figure 3 (b) is along Figure 2 A rough cross-sectional view of the BB line shown.

[0047] like Figure 2 and Figure 3 As shown, the coil component 100 of this embodiment includes a magnetic body 10 and a coil 20 overlapping the magnetic body 10 in the thickness direction. The magnetic body 10 includes a first magnetic body layer 11 and a second magnetic body layer 12 stacked on top of each other. The first magnetic body layer 11 and the second magnetic body layer 12 are made of different magnetic materials. Specifically, the first magnetic body layer 11 is made of a nanocrystalline alloy material, and the second magnetic body layer 12 is made of a composite magnetic material in which magnetic powder F is mixed in resin R. The magnetic powder F contained in the second magnetic body layer 12 may also have a flat shape in which the plane direction perpendicular to the thickness direction is set as the long side direction. The magnetic powder F contained in the second magnetic body layer 12 is not particularly limited as long as it exhibits soft magnetic properties, for example, it may also be made of a material with Fe as the main component. The first magnetic body layer 11 and the second magnetic body layer 12 may also be bonded together via an adhesive layer 13 located between them.

[0048] The coil 20 overlaps with the magnetic body 10 in a face-to-face manner with the second magnetic body layer 12. In other words, the coil 20 and the second magnetic body layer 12 of the magnetic body 10 are arranged opposite each other. Figure 3 As shown, the pattern width of coil 20 can also be thinner, becoming closer to the shape of magnetic body 10. Figure 3 In the example shown, the surface of the coil 20 facing the magnetic body 10 is curved, and the surface of the coil 20 facing the opposite side of the magnetic body 10 is approximately flat. This cross-sectional shape is obtained by forming the coil 20 on a substrate present on the surface of the coil 20 facing the opposite side of the magnetic body 10, transferring the coil 20 in an overlapping manner with the magnetic body 10, and then peeling off the substrate. Thus, no substrate used to form the coil 20 remains, and therefore, the overall thickness of the coil component 100 can be reduced. An insulating layer 14 made of acrylic resin or the like can also be interposed between the coil 20 and the second magnetic body layer 12. Furthermore, viewed from the magnetic body 10, a metal sheet 30 can be provided on the opposite side of the coil 20, facing the first magnetic body layer 11, and this metal sheet 30 is disposed opposite to the first magnetic body layer 11.

[0049] exist Figure 2 In the example shown, coil 20 is wound approximately 5 turns on the surface of magnetic body 10. The outer peripheral end 21 of coil 20 is connected to terminal electrode 43 via wiring 41 provided on flexible substrate 40. The inner peripheral end 22 of coil 20 is connected to terminal electrode 44 via wiring 42 provided on flexible substrate 40. Figure 3 As shown in (b), a portion of the flexible substrate 40 is disposed within a slit 15, which is located on the magnetic body 10. The inner peripheral end 22 of the coil 20 is connected to the wiring 42 on the flexible substrate 40 via solder 50. Although not shown, the outer peripheral end 21 of the coil 20 is also connected to the wiring 41 on the flexible substrate 40 via solder 50.

[0050] With this structure, when a magnetic flux is generated by flowing current through the terminal electrodes 43 and 44 to the coil 20, the magnetic body 10 functions as a magnetic circuit for the flux. Therefore, almost no magnetic flux is applied to the metal sheet 30, suppressing losses caused by the metal sheet 30. Here, the first magnetic layer 11 contained in the magnetic body 10 is made of a nanocrystalline alloy material, thus exhibiting very high relative permeability and excellent magnetic saturation characteristics. However, because the nanocrystalline alloy material is conductive, when the first magnetic layer 11 is used alone, the resistance of the coil 20 may increase and the Q value of the coil 20 may decrease due to the influence of eddy currents generated within the first magnetic layer 11. Considering this, in this embodiment, a second magnetic layer 12 is added to the coil 20 side. The second magnetic layer 12 is made of a composite magnetic material in which magnetic powder F is mixed into the resin R. Therefore, although its relative permeability is lower than that of the first magnetic layer 11, by being positioned between the first magnetic layer 11 and the coil 20, the resistance of the coil 20 and the Q value of the coil 20 are improved. Furthermore, the composite magnetic material in which magnetic powder F is mixed into resin R can be coated thinly to less than 100 μm. Therefore, compared with the case where a bulk ferrite sintered body or the like is used as the material of the second magnetic layer 12, the overall thickness can be reduced.

[0051] The relative permeability of the second magnetic layer 12 can also be increased in a planar direction perpendicular to the thickness direction. This is achieved by using magnetic powder F with a flat shape having the planar direction as the long side as the magnetic powder F contained in the second magnetic layer 12.

[0052] The thickness T1 of the first magnetic layer 11 can also be less than or equal to the thickness T2 of the second magnetic layer 12. Figure 3 In the example shown, the thickness T1 of the first magnetic layer 11 is thinner than the thickness T2 of the second magnetic layer 12. The thickness T1 of the first magnetic layer 11 can also be 10 μm or more and 30 μm or less. The thickness T2 of the second magnetic layer 12 can also be 30 μm or more and 100 μm or less. Thus, when the thickness T1 of the first magnetic layer 11 is less than or equal to the thickness T2 of the second magnetic layer 12, it is possible to increase the relative permeability of the magnetic body 10 as a whole while simultaneously reducing the overall thickness of the magnetic body 10.

[0053] The first magnetic layer 11 can be a sheet-like component that is not divided in the planar direction, or it can be an assembly of multiple block-like components that are divided in the planar direction.

[0054] exist Figure 4In the example shown in (a), the first magnetic layer 11 is composed of a nanocrystalline alloy sheet extending in a planar direction perpendicular to the stacking direction. That is, the first magnetic layer 11 is not divided in the planar direction and is composed of a single nanocrystalline alloy sheet. This improves the relative permeability of the first magnetic layer 11. When using a nanocrystalline alloy sheet that is not divided in the planar direction as the material of the first magnetic layer 11, two or more nanocrystalline alloy sheets can also be overlapped. Furthermore, in Figure 4 In the example shown in (a), multiple microcracks can also be added to the nanocrystalline alloy sheet.

[0055] exist Figure 4 In the example shown in (b), the first magnetic layer 11 is composed of multiple nanocrystalline alloy blocks divided in a planar direction perpendicular to the stacking direction. That is, slits 11A are provided on the first magnetic layer 11, dividing the first magnetic layer 11 into multiple segments. This reduces the eddy current generated in the first magnetic layer 11. Figure 4 In the example shown in (b), gaps can also be present between blocks, and multiple microcracks can be added to each nanocrystalline alloy block.

[0056] exist Figure 4 In the example shown in (c), two magnetic bodies 10A and 10B are stacked. Both magnetic bodies 10A and 10B can have the same properties as... Figure 4 The magnetic body 10 shown in (b) has the same structure. In this way, if multiple sets of magnetic bodies 10 containing the first magnetic body layer 11 and the second magnetic body layer 12 are stacked, the overall thickness can be increased without increasing the thickness of the first magnetic body layer 11 and the second magnetic body layer 12 individually, thereby improving the magnetic properties.

[0057] In the case where the alloy is divided into multiple nanocrystalline blocks by providing slits 11A in the first magnetic layer 11, such as Figure 5 As shown, the planar shape of each block can also be a square. Figure 5 The location of coil 20 is also shown in the diagram. Figure 5 The reference numeral 23 in the attached figure indicates the outermost peripheral edge of coil 20. Figure 5 The reference numeral 24 in the attached figure indicates the innermost circumferential edge of coil 20. Figure 5 In the example shown, the dimension of one side of the nanocrystalline alloy block divided by slit 11A is smaller than the dimension in the planar direction of the opening region surrounded by the innermost peripheral edge 24 of coil 20. This effectively reduces the eddy currents generated in the first magnetic layer 11. Furthermore, in Figure 5In the example shown, the dimension of one side of the nanocrystalline alloy block divided by slit 11A is smaller than the coil width defined by the widths of the outermost peripheral edge 23 and the innermost peripheral edge 24 of the coil 20. This allows for a more effective reduction of eddy currents generated in the first magnetic layer 11.

[0058] The planar shape of the nanocrystalline alloy block divided by slit 11A does not need to be a square; it can also be a rectangle or a triangle. If the planar shape of the nanocrystalline alloy block divided by slit 11A is not a square, the dimension of one side of the nanocrystalline alloy block can be defined by the dimension of the largest side or the dimension of the smallest side.

[0059] As explained above, the coil component 100 of this embodiment uses a magnetic body 10 that is laminated with a first magnetic body layer 11 made of a nanocrystalline alloy material and a second magnetic body layer 12 made of a composite magnetic material in which magnetic powder is mixed in resin. Therefore, it is possible to obtain high magnetic properties while reducing the overall thickness. Thus, if the coil component 100 of this embodiment is used as part of a power supply device or a power receiving device for a wireless power transmission device, the resistance value and Q value of the coil 20 are improved, thereby achieving high power transmission efficiency.

[0060] The above describes the implementation of the technology disclosed herein. However, the technology disclosed herein is not limited to the above implementation. Various modifications can be made without departing from its spirit, and these modifications are also included within the scope of the technology disclosed herein.

[0061] The technology disclosed herein includes the following structural examples, but is not limited thereto.

[0062] One aspect of the magnetic material disclosed herein includes a first magnetic material layer and a second magnetic material layer stacked on the first magnetic material layer. The first magnetic material layer is made of a nanocrystalline alloy material, and the second magnetic material layer is made of a composite magnetic material in which magnetic powder is mixed in a resin. Thus, while reducing the overall thickness, the electrical characteristics of the coils can be improved in the case of overlapping coils.

[0063] In the aforementioned magnetic material, the first magnetic material layer may also comprise multiple nanocrystalline alloy blocks segmented in a plane perpendicular to the stacking direction. This reduces the eddy currents generated within the first magnetic material layer.

[0064] In the aforementioned magnetic material, the first magnetic layer may also comprise a nanocrystalline alloy sheet extending in a planar direction perpendicular to the stacking direction. This improves the relative permeability of the first magnetic layer in the planar direction.

[0065] In the aforementioned magnetic material, the magnetic powder contained in the second magnetic material layer can also have a flat shape. This increases the relative permeability of the second magnetic material layer in the planar direction.

[0066] In the aforementioned magnetic material, the relative permeability of the first magnetic layer can also be higher than that of the second magnetic layer. Therefore, the overall relative permeability of the magnetic material can be improved.

[0067] In the aforementioned magnetic material, the thickness of the first magnetic layer can be less than or equal to the thickness of the second magnetic layer. This allows for a reduction in the overall thickness of the magnetic material.

[0068] One aspect of the coil component disclosed herein includes the aforementioned magnetic body and a coil overlapping the magnetic body, wherein the coil and a second magnetic body layer of the magnetic body are disposed opposite to each other. Accordingly, the resistance value of the coil can be reduced, and the Q value of the coil can be increased.

[0069] In the aforementioned coil component, the first magnetic layer may also comprise multiple nanocrystalline alloy blocks divided in a planar direction perpendicular to the stacking direction, wherein the planar dimension of each nanocrystalline alloy block is smaller than the planar dimension of the opening region surrounded by the coil. This effectively reduces eddy currents generated in the first magnetic layer.

[0070] The aforementioned coil component may also include a metal sheet disposed opposite to the first magnetic layer of the magnetic body. Even with such a metal sheet present, the magnetic flux is blocked by the magnetic body, thus suppressing the generation of eddy current losses.

[0071] In the aforementioned coil component, multiple sets of magnetic materials, including a first magnetic material layer and a second magnetic material layer, can be stacked. This allows for the acquisition of higher magnetic properties.

Claims

1. A magnetic body, wherein, have: First magnetic layer; and A second magnetic layer is stacked on top of the first magnetic layer. The first magnetic layer is composed of a nanocrystalline alloy material. The second magnetic layer is composed of a composite magnetic material in which magnetic powder is mixed in resin.

2. The magnetic body according to claim 1, wherein, The first magnetic layer comprises multiple nanocrystalline alloy blocks divided in a plane perpendicular to the stacking direction.

3. The magnetic body according to claim 1, wherein, The first magnetic layer comprises a nanocrystalline alloy sheet extending in a planar direction perpendicular to the stacking direction.

4. The magnetic body according to claim 1, wherein, The magnetic powder contained in the second magnetic layer has a flat shape.

5. The magnetic body according to claim 1, wherein, The relative permeability of the first magnetic layer is higher than that of the second magnetic layer.

6. The magnetic body according to claim 1, wherein, The thickness of the first magnetic layer is less than or equal to the thickness of the second magnetic layer.

7. A coil component, wherein, have: The magnetic body according to any one of claims 1 to 6; and A coil, which overlaps with the magnetic body, The coil is disposed opposite to the second magnetic layer of the magnetic body.

8. The coil component according to claim 7, wherein, The first magnetic layer comprises multiple nanocrystalline alloy blocks segmented in a plane perpendicular to the stacking direction. The dimension of the nanocrystalline alloy block in the planar direction is smaller than the dimension of the opening region surrounded by the coil in the planar direction.

9. The coil component according to claim 7, wherein, It also includes: a metal sheet disposed opposite to the first magnetic body layer of the magnetic body.

10. The coil component according to claim 7, wherein, Multiple sets of magnetic bodies, including the first magnetic body layer and the second magnetic body layer, are stacked.

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