Cooling structure of the power module

Abstract

The power module includes a substrate, an electronic component disposed on an upper surface of the substrate, a lower board electrically connected to the electronic component via the substrate, and an upper board electrically connected to another end of the at least one support pillar opposite an end of the at least one support pillar electrically connected to the at least one lower board, the at least one upper board being electrically connected to the substrate. The support pillar extends between the lower board and the upper board. The support pillar includes a first end electrically connected to the lower board and a second end electrically connected to the upper board. The magnetic material is disposed around a periphery of the support pillar.

Description

Technical Field

[0006] , , ,

[0001] The present invention relates to a power module. More specifically, the present invention relates to improving the performance of a power module by cooling a heat-generating power element in the power module.

Background Art

[0002] Known power modules include heat-generating components such as power elements of the power module. The heat-generating components are connected to a heat sink, and part of the heat generated by the heat-generating components is transmitted to the heat sink that helps dissipate the heat.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, a typical arrangement in a known power module requires a large space and is not preferable when miniaturization of the power module is required. Further, when a heat-generating power component has to be installed near an inductive component, the cooling efficiency decreases because the inductive component has a low thermal conductivity. When the cooling efficiency decreases, the heat-generating power component cannot generate a large current.

[0005] Patent Document 1 shows an inductor in a DC-DC converter. However, the core of the structure of the inductor 4i is toroidal and lacks sufficient heat dissipation capacity for a large current power component.

Means for Solving the Problems

[0006] To solve the above problems, a preferred embodiment of the present invention provides a power supply module that can be miniaturized while also providing sufficient cooling to generate a large current. A preferred embodiment of the present invention includes a substrate and an electronic component provided on the upper surface of the substrate. Located above the electronic components, The lower board is electrically connected to the electronic components via the circuit board. , electric Connected to the circuit board via air on A power module is provided, including a lower board and an upper board. The support column extends between the lower board and the upper board. The support column includes a first end connected to the lower board and a second end connected to the upper board. Magnetic material is provided around the periphery of the support column. The lower board, support column, and upper board define the inductor.

[0007] The electronic components may be thermally connected to the lower board. The electronic components may be thermally connected to the lower board via a thermally conductive material. 。

[0008] The lower board may be connected to the top surface of the substrate. The lower board may include an upright portion of the lower board extending upward from the substrate, a curved portion of the lower board located at the end of the upright portion of the lower board, and a flat portion of the lower board extending from the curved portion of the lower board along a plane parallel or substantially parallel to the top surface of the substrate. The top surface of the flat portion of the lower board may be connected to the first end of one of the supports.

[0009] The upper surface of the electronic component may be thermally connected to the lower surface of the flat portion of the lower board. A thermally conductive material may be provided between the upper surface of the electronic component and the lower surface of the flat portion of the lower board. The surface area of ​​the flat portion of the lower board may be larger than the surface area of ​​the upright portion of the lower board. The maximum height of electronic components is less than or equal to the distance between the bottom surface of the flat portion of the lower board and the top surface of the substrate.

[0010] The electronic components may be molded, at least partially, within the resin material. The maximum height of the resin material may be less than or equal to the distance between the lower surface of the flat portion of the lower board and the upper surface of the substrate. The upper board may include an upper board flat portion extending along a plane parallel or substantially parallel to the top surface of the substrate, an upper board curved portion provided at the end of the upper board flat portion, and an upper board upright portion that may extend from the upper board curved portion and may be electrically connected to the substrate. The sum of the maximum height of the electronic components, the maximum thickness of the lower board flat portion, and the maximum thickness of the support column may be equal to the total distance between the bottom surface of the upper board flat portion and the top surface of the substrate. The total surface area of ​​the upper board flat portion may be greater than the total surface area of ​​the upper board upright portion.

[0011] The support columns may be cylindrical in shape. The electronic components may include field-effect transistors. The module may further include additional support columns, and the support columns and additional support columns may be arranged on a straight line extending in a direction intersecting the extending direction of the lower board.

[0012] A preferred embodiment of the present invention comprises a first substrate and a second substrate, and a first electronic component provided on the upper surface of the first substrate. Located above the first electronic component, A first lower board electrically connected to a first electronic component via a first substrate; a first upper board electrically connected to the first substrate; a first support column extending between the first lower board and the first upper board and including a first end electrically connected to the first lower board and a second end electrically connected to the first upper board; a first magnetic material provided around the first support column; and a second electronic component provided on the upper surface of the second substrate. Located above the second electronic component, The present invention provides a power supply module comprising: a second lower board electrically connected to a second electronic component via a second substrate; a second upper board electrically connected to the second substrate; a second support column extending between the second lower board and the second upper board and including a first end electrically connected to the second lower board and a second end electrically connected to the second upper board; and a second magnetic material provided around the second support column. The first lower board, the first support column, the first upper board, the second lower board, the second support column, and the second upper board are magnetically connected to each other. The first lower board, first support, first upper board, first magnetic material, second lower board, second support, second upper board, and second magnetic material define at least one inductor.

[0013] The first magnetic material and the second magnetic material may be fixed to each other. The first magnetic material and the second magnetic material may be provided together as a single monolithic member. The above and other features, elements, characteristics, steps, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings.

Brief Description of the Drawings

[0014] [Figure 1] A side view of a power module according to a first preferred embodiment of the present invention is shown. [Figure 2A] A perspective view of a part of a power module according to a first preferred embodiment of the present invention is shown. [Figure 2B] A perspective view of a part of a power module according to a first preferred embodiment of the present invention is shown. [Figure 2C] A perspective view of a part of a power module according to a first preferred embodiment of the present invention is shown. [Figure 2D] A perspective view of a part of a power module according to a first preferred embodiment of the present invention is shown. [Figure 2E] A perspective view of a power module according to a first preferred embodiment of the present invention is shown. [Figure 2F] A circuit diagram of a power module according to a first preferred embodiment of the present invention is shown. [Figure 3] A perspective view of a power module according to a modified form of a first preferred embodiment of the present invention is shown. [Figure 4A] A perspective view of a power module according to a second preferred embodiment of the present invention is shown. [Figure 4B] A perspective view of a power module according to a second preferred embodiment of the present invention is shown. [Figure 5] A perspective view of a power module according to a third preferred embodiment of the present invention is shown. [Figure 6A] A perspective view of a power module according to a fourth preferred embodiment of the present invention is shown. [Figure 6B]A perspective view of a power module according to a fourth preferred embodiment of the present invention is shown. [Figure 6C] A perspective view of a part of a power module according to a fourth preferred embodiment of the present invention is shown. [Figure 6D] A perspective view of a part of a power module according to a fourth preferred embodiment of the present invention is shown. [Figure 7A] A perspective view of a power module according to a fifth preferred embodiment of the present invention is shown. [Figure 7B] A perspective view of a power module according to a fifth preferred embodiment of the present invention is shown. [Figure 7C] A perspective view of a power module according to a modified form of a fifth preferred embodiment of the present invention is shown. [Figure 8A] A perspective view of a power module according to a sixth preferred embodiment of the present invention is shown. [Figure 8B] A perspective view of a part of a power module according to a sixth preferred embodiment of the present invention is shown. [Figure 8C] A perspective view of a part of a power module according to a sixth preferred embodiment of the present invention is shown. -- [Figure 9] )]]A perspective view of a part of a power module according to a seventh preferred embodiment of the present invention is shown. [Figure 10] A perspective view of a power module according to an eighth preferred embodiment of the present invention is shown.

Mode for Carrying Out the Invention

[0015] First Preferred Embodiment A power module 1 according to a first preferred embodiment of the present invention will be described with reference to FIGS. 1 to 2F. FIG. 1 is a side view of the power module 1 according to the first preferred embodiment of the present invention. FIGS. 2A to 2D are perspective views of a part of the power module 1 according to the first preferred embodiment of the present invention. FIG. 2E is a perspective view of the power module 1 according to the first preferred embodiment of the present invention. FIG. 2F is a circuit diagram of the power module 1 according to the first preferred embodiment of the present invention.

[0016] As shown in Figure 1, the power module 1 may include a substrate 10, one or more electronic components 40 on the surface of the substrate 10, a lower board 21 extending from the upper surface of the substrate 10 to cover the electronic components 40, one or more support columns 30 extending from the upper surface of the lower board 21, a magnetic material 31 surrounding one or more support columns 30, and an upper board 22 extending from the substrate 10 to cover the upper ends of one or more support columns 30. The electronic components 40 may include, for example, power elements (e.g., field-effect transistors), capacitors, resistors, etc.

[0017] The lower board 21 may include a pair of lower board portions 21A and 21B spaced apart from each other with a gap 214 between them, as shown in Figure 2B. The lower board 21 may include a lower board upright portion 211, a lower board curved portion 212, and a lower board flat portion 213. The lower board upright portion 211 extends perpendicular or substantially perpendicular to the upper surface of the substrate 10 within the manufacturing tolerance range and / or measurement tolerance range. The lower board flat portion 213 extends parallel or substantially parallel to the upper surface of the substrate 10 within the manufacturing tolerance range and / or measurement tolerance range. The surface area of ​​the lower board flat portion 213 may be larger than the surface area of ​​the lower board upright portion 211. However, the surface area of ​​the lower board flat portion 213 may be less than or equal to that of the lower board upright portion 211. The bottom of the lower board upright portion 211 may be fixed within an opening 1021 defined on the substrate 10. The lower board 21 may be electrically connected to one or more electronic components 40 via solder and / or wiring defined on or within the substrate 10.

[0018] As shown in Figure 2D, the upper board 22 may include a pair of upper board portions 22A and 22B spaced apart from each other with a gap 224 between them. The upper board 22 may include an upper board upright portion 221, an upper board curved portion 222, and an upper board flat portion 223. The upper board upright portion 221 extends perpendicular or substantially perpendicular to the upper surface of the substrate 10 within the manufacturing tolerance range and / or measurement tolerance range. The upper board flat portion 223 extends parallel or substantially parallel to the upper surface of the substrate 10 within the manufacturing tolerance range and / or measurement tolerance range. The bottom of the upper board upright portion 221 may be fixed within an opening 1022 defined in the substrate 10. The total surface area of ​​the upper board flat portion 223 may be greater than the total surface area of ​​the upper board upright portion 221. However, the total surface area of ​​the upper board flat portion 223 may be less than or equal to that of the upper board upright portion 221. The upper board 22 may be electrically connected to one or more electronic components 40 via solder and / or wiring defined on or within the substrate 10.

[0019] At least one support column 30 extends from the lower board flat portion 213 to the upper board flat portion 223. The lower board 21 and the upper board 22 are electrically connected to each other via at least one support column 30. As shown in Figure 2C, for example, at least one support column 30 may include a pair of support columns. However, a different number of support columns may be used. At least one support column 30 may be cylindrical, but any other shape may be used. At least one support column 30 is surrounded by magnetic material 31. The lower board 21, upper board 22, at least one support column 30, and magnetic material 31 together may define one or more inductors. Furthermore, the structure of the lower board 21, upper board 22, at least one support column 30, and magnetic material 31 may define a heat sink that can dissipate the heat generated inside the power module 1.

[0020] The maximum height of at least one of the electronic components 40 is the same as or substantially the same as the distance between the lower board flat portion 213 and the upper surface of the substrate 10. Furthermore, the maximum height of at least one of the electronic components 40 may be less than the distance between the lower board flat portion 213 and the upper surface of the substrate 10.

[0021] Figures 2E and 2F show an example of a circuit layout provided in the power module 1. The circuit layout may include a transformer TX1 provided between a pair of transistors Q1 and Q2 and a pair of transistors Q3 and Q4. The primary winding P1 includes node B, and the secondary winding S1 includes node A. Node B is connected between transistors Q3 and Q4 and corresponds to the connection of the upper board 22 to the substrate 10. Node A is connected between transistors Q1 and Q2 and corresponds to the connection of the lower board 21 to the substrate 10. The ends of the primary winding P1 and secondary winding S1 that are not connected to nodes A and B are connected to a capacitor C1 and an AC power supply I1, which are connected in parallel between the primary winding P1 and secondary winding S1 and ground. The pair of transistors Q1 and Q2, and the pair of transistors Q3 and Q4 are also connected in parallel between a voltage source V1 and ground.

[0022] Figure 3 shows a power module 1A according to a modified version of the first preferred embodiment of the present invention. The power module 1A according to the modified version of the first preferred embodiment may differ from the power module 1 according to the first preferred embodiment in that the electronic components 40 on the substrate 10 are encapsulated in a thermally conductive resin material 401. Furthermore, the thermally conductive resin material 401 supports the lower board 21, thereby stabilizing the structure of the power module 1A. The maximum height of at least one of the electronic components 40 may be substantially the same as or less than the maximum height of the resin material 401. By encapsulating the electronic components 40 in the resin material 401, better heat transfer between the substrate 10, the electronic components 40, and the lower board 21 can be provided while simultaneously improving stability.

[0023] Second Preferred Embodiment A power supply module 2 according to a second preferred embodiment of the present invention will be described with reference to Figures 4A and 4B. Figure 4A is a perspective view of an example of a power supply module 2 according to a second preferred embodiment of the present invention. Figure 4B is another perspective view of an example of a power supply module 2 according to a second preferred embodiment of the present invention, and is semi-transparent to show the internal shape of the components of the power supply module 2.

[0024] As shown in Figures 4A and 4B, the power module 2 according to the second preferred embodiment may differ from the power module 1 according to the first preferred embodiment in that the shape of the support column 2030 and the magnetic material 2031 may be rectangular or cubic. Furthermore, the support column 2030 may be polygonal (pentagonal, hexagonal, etc.). Other components of the power module 2 according to the second preferred embodiment may be the same as those of the power module 1 according to the first preferred embodiment, and descriptions of the same parts are omitted for simplicity.

[0025] Third Preferred Embodiment A power supply module 3 based on a third preferred embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a perspective view of an example of a power supply module 3 according to a third preferred embodiment of the present invention, and is semi-transparent to show the internal shape of the components of the power supply module 3.

[0026] As shown in Figure 5, the power module 3 according to the third preferred embodiment may differ from the power module 1 according to the first preferred embodiment in that the support column 30 is surrounded by a magnetic material 2031 which may be cylindrical or cylindrical in shape. Other components of the power module 3 according to the third preferred embodiment may be the same as those of the power module 1 according to the first preferred embodiment, and descriptions of the same parts are omitted for simplicity.

[0027] Fourth Preferred Embodiment A power supply module 4 according to a fourth preferred embodiment of the present invention will be described with reference to Figures 6A to 6D. Figures 6A and 6B are perspective views of the power supply module 4 according to the fourth preferred embodiment of the present invention. Figures 6C and 6D show partial perspective views of the power supply module 4 according to the fourth preferred embodiment of the present invention.

[0028] As shown in Figures 6A to 6D, the power module 4 according to the fourth preferred embodiment may differ from the power module 1 according to the first preferred embodiment in that the shape of the support column 4030 is surrounded by a magnetic material 4031 which may be rectangular or cubic. Furthermore, the magnetic material 4031 may include a separately provided structure having the shape of the Greek letter pi (π). The lower board 4021 and the upper board 4022 may be defined as a pair of separate structures that directly contact only the upper and lower surfaces of the corresponding support column 4030. Other components of the power module 4 according to the fourth preferred embodiment may be the same as those of the power module 1 according to the first preferred embodiment, and descriptions of the same parts are omitted for simplicity.

[0029] Fifth Preferred Embodiment A power supply module 5 according to a fifth preferred embodiment of the present invention will be described with reference to Figures 7A and 7B. Figures 7A and 7B are perspective views of the power supply module 5 according to a fifth preferred embodiment of the present invention.

[0030] As shown in Figures 7A and 7B, the power module 5 according to the fifth preferred embodiment may differ from the power module 1 according to the first preferred embodiment in that a plurality of support columns 5030, which may be rectangular or cubic in shape, are surrounded by a magnetic material 5031. The magnetic material 5031 may include separately provided structures having the shape of a single long side with a plurality of vertical projections extending between pairs of support columns 5030. Furthermore, the lower board 5021 and upper board 5022 may be defined as a pair of separate structures that directly contact only the upper and lower surfaces of the corresponding support columns 5030. For example, the four vertical projections of the magnetic material 5031 may be provided adjacent to the four support columns 5030. Other components of the power module 5 according to the fifth preferred embodiment may be the same as those of the power module 1 according to the first preferred embodiment, and descriptions of the same parts are omitted for simplicity. By increasing the number of inductors (corresponding to the support columns 5030 and magnetic material 5031) in the power module 5 according to the fifth preferred embodiment compared to that in the power module 1 according to the first preferred embodiment, the performance of the power module 5 according to the fifth preferred embodiment can be improved compared to that of the power module 1 according to the first preferred embodiment.

[0031] Figure 7C shows a power module 5A according to a modified form of the fifth preferred embodiment of the present invention. The power module 5A according to the fifth preferred embodiment differs from the power module 5 according to the fifth preferred embodiment in that the magnetic material 5031 is defined by a plurality of structures having the shape of the Greek letter pi (π). Furthermore, instead of a single substrate, a pair of substrates 10A and 10B are provided. Similar to the power module 5, the performance of the power module 5A can be improved by increasing the number of inductors in the power module 5A.

[0032] Sixth Preferred Embodiment A power supply module 6 according to a sixth preferred embodiment of the present invention will be described with reference to Figures 8A to 8C. Figure 8A is a perspective view of a power supply module 6 based on the sixth preferred embodiment of the present invention. Figures 8B and 8C show partial perspective views of a power supply module 6 based on a fourth preferred embodiment of the present invention.

[0033] As shown in Figure 8A, the power module 6 according to the sixth preferred embodiment may differ from the power module 1 according to the first preferred embodiment in that a plurality of pillars 6030, which may be rectangular or cubic in shape, are surrounded by a magnetic material 6031. The magnetic material 6031 may include a separately provided structure having the shape of a single long side with a plurality of vertical projections extending between pairs of pillars 6030. Furthermore, the upper board 6022 may be defined by a plurality of separate structures that directly contact only the upper surfaces of the corresponding pillars 6030. In contrast, the lower board 6021 may include a single structure having an opening 6033 through which the lower part of the upper board 6022 passes and reaches the substrate 6010.

[0034] Figures 8B and 8C show the lower board 6021. The opening 6033 may include a curved projection 6034 provided on the periphery of the opening 6033. The curved projection 6034 extends downward toward the upper surface of the substrate 6010. The opening may overlap with a portion of the lower surface of the support column 6030. The remaining portion of the lower board 6021 may have a structure similar to the structure of the power module 1 according to the first preferred embodiment. Inserting a portion of the support column 6030 into the opening 6033 can increase the stability of the power module 6.

[0035] Seventh Preferred Embodiment A power supply module 7 based on a seventh preferred embodiment of the present invention will be described with reference to Figure 9. Figure 9 is a perspective view of a power supply module 7 based on a seventh preferred embodiment of the present invention.

[0036] As shown in Figure 9, the power module 7 based on the seventh preferred embodiment may differ from the power module 1 based on the first preferred embodiment in that a plurality of support columns 7030, which may be rectangular or cubic in shape, are surrounded by a magnetic material 7031. The magnetic material 7031 may include separately provided structures having the shape of a single long side with a plurality of vertical projections extending between pairs of support columns 7030. Furthermore, the upper board 7022 may include a single structure having an opening 7033, while the lower board 7021 may be defined by a plurality of separate structures that directly contact only the underside of the corresponding support columns 7030. The opening 7033 may include curved projections 7034 that extend downward between adjacent individual structures of the lower board 7021 and reach the substrate 7010. Inserting a portion of the support columns 7030 into the opening 7033 can increase the stability of the power module 7.

[0037] Eighth Preferred Embodiment A power supply module 8 according to an eighth preferred embodiment of the present invention will be described with reference to Figure 10. Figure 10 is a perspective view of a power supply module 8 according to an eighth preferred embodiment of the present invention.

[0038] As shown in Figure 10, the power module 8 according to the eighth preferred embodiment may differ from the power module 1 according to the first preferred embodiment in that a plurality of support columns 8030, which may be rectangular or cubic in shape, are surrounded by a magnetic material 8031. The magnetic material 8031 ​​may include a plurality of structures having the shape of the Greek letter pi (π). A wide gap 8066 may be defined between adjacent structures of the magnetic material 8031.

[0039] The configurations of the preferred embodiments and modifications described above can be appropriately combined with each other and produce effects corresponding to each combination. It should be understood that the foregoing description is merely illustrative of the present invention. Those skilled in the art can devise various alternative and modified forms without departing from the present invention. Accordingly, the present invention is intended to encompass all such alternative, modified, and variant forms that fall within the scope of the appended claims.

Claims

1. A power module, circuit board and An electronic component provided on the upper surface of the substrate, A lower board located above the aforementioned electronic component and electrically connected to the aforementioned electronic component via the substrate, An upper board electrically connected to the aforementioned substrate, A support column extending between the lower board and the upper board, A first end electrically connected to the lower board, A support column including a second end electrically connected to the upper board, The system comprises a magnetic material provided around the periphery of the support column, The lower board, the support column, the upper board, and the magnetic material define an inductor, forming a power module.

2. The module according to claim 1, wherein the electronic component is thermally connected to the lower board.

3. The module according to claim 1, wherein the electronic component is thermally connected to the lower board via a thermally conductive material.

4. The lower board is connected to the upper surface of the substrate, The lower board includes a lower board upright portion extending upward from the substrate, a lower board curved portion located at the end of the lower board upright portion, and a lower board flat portion extending from the lower board curved portion along a plane parallel or substantially parallel to the upper surface of the substrate. The module according to claim 1, wherein the upper surface of the lower board flat portion is connected to the first end of the one support column.

5. The module according to claim 4, wherein the upper surface of the electronic component is thermally connected to the lower surface of the flat portion of the lower board.

6. The module according to claim 5, wherein a thermally conductive material is provided between the upper surface of the electronic component and the lower surface of the flat portion of the lower board.

7. The module according to claim 4, wherein the surface area of ​​the flat portion of the lower board is larger than the surface area of ​​the upright portion of the lower board.

8. The module according to claim 4, wherein the maximum height of the electronic component is less than or equal to the distance between the lower surface of the lower flat portion of the board and the upper surface of the substrate.

9. The module according to claim 8, wherein at least a portion of the electronic component is molded within a resin material.

10. The module according to claim 9, wherein the maximum height of the resin material is less than or equal to the distance between the lower surface of the lower board flat portion and the upper surface of the substrate.

11. The aforementioned upper board is An upper board flat portion extending along a plane parallel or substantially parallel to the upper surface of the substrate, The curved portion of the upper board is provided at the end of the flat portion of the upper board, The module according to claim 8, comprising an upper board upright portion extending from the upper board curved portion and electrically connected to the substrate.

12. The module according to claim 11, wherein the sum of the maximum height of the electronic component, the maximum thickness of the lower board flat portion, and the maximum thickness of the support column is the same as the total distance between the lower surface of the upper board flat portion and the upper surface of the substrate.

13. The module according to claim 11, wherein the total surface area of ​​the flat portion of the upper board is greater than the total surface area of ​​the upright portion of the upper board.

14. The module according to any one of claims 1 to 13, wherein the support column is cylindrical in shape.

15. The module according to any one of claims 1 to 13, wherein the electronic component includes a field-effect transistor.

16. With additional support columns, The module according to any one of claims 1 to 13, wherein the support column and the additional support column are arranged on a straight line extending in a direction intersecting the extending direction of the lower board.

17. A power module, A first substrate and a second substrate, A first electronic component provided on the upper surface of the first substrate, A first lower board is located above the first electronic component and is electrically connected to the first electronic component via the first substrate, A first upper board electrically connected to the first substrate, A first support column extending between the first lower board and the first upper board, A first end electrically connected to the first lower board, A first support column, including a second end electrically connected to the first upper board, A first magnetic material provided around the first support column, A second electronic component provided on the upper surface of the second substrate, A second lower board is located above the second electronic component and is electrically connected to the second electronic component via the second substrate, A second upper board electrically connected to the second substrate, A second support column extending between the second lower board and the second upper board, The first end is electrically connected to the second lower board, A second support column, including a second end electrically connected to the second upper board, The device comprises a second magnetic material provided around the second support column, The first lower board, the first support column, the first upper board, the second lower board, the second support column, and the second upper board are magnetically connected to each other. The first lower board, the first support column, the first upper board, the first magnetic material, the second lower board, the second support column, the second upper board, and the second magnetic material define at least one inductor. Power module.

18. The module according to claim 17, wherein the first magnetic material and the second magnetic material are fixed to each other.

19. The module according to claim 18, wherein the first magnetic material and the second magnetic material are provided together as a single monolithic member.

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