Coil component and coil-incorporated substrate

Abstract

To provide a coil component in which the leak of a magnetic flex is suppressed.SOLUTION: A coil component A2 includes a coil 3 that generates a magnetic field by input current from the outside. The coil 3 includes a plurality of first circulation parts 31 and a plurality of second circulation parts 32 each having a rectangular annular shape when viewed in a first direction (circumferential direction t). The first circulation parts 31 are arranged in the circumferential direction t and form a first cylindrical part 5A. The second circulation parts 32 are arranged in the circumferential direction t and form a second cylindrical part 5B. The second cylindrical part 5B exists inside the first cylindrical part 5A when viewed in the circumferential direction t. Each of the cylindrical part 5A and the second cylindrical part 5B has an annular shape when viewed in a thickness direction (axial direction s) that is orthogonal to the circumferential direction t. The direction of the input current flowing in each of the first circulation parts 31 and the direction of the input current flowing in each of the second circulation parts 32 are the same.SELECTED DRAWING: Figure 23

Description

[Technical Field]

[0001] The present disclosure relates to a coil component and a coil-embedded substrate. [Background technology]

[0002] Coil components such as inductors and transformers are mounted in various electrical devices. For example, Patent Document 1 discloses coil components (inductors and transformers) using spiral coils. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-124250 Summary of the Invention [Problem to be solved by the invention]

[0004] It is generally believed that the less magnetic flux leakage there is in an inductor or transformer, the better, because magnetic flux leakage can cause radiated noise and heat generation.

[0005] The present disclosure has been made in view of the above circumstances, and one object thereof is to provide a coil component that suppresses magnetic flux leakage and a coil-embedded substrate that includes the coil component. [Means for solving the problem]

[0006] A coil device provided by a first aspect of the present disclosure includes a primary winding that generates a magnetic field in response to an external input current, and a secondary winding through which an induced current generated by the magnetic field flows. The primary winding includes a plurality of primary-side first winding portions and a plurality of primary-side second winding portions, each of which is annular when viewed in a first direction. The secondary winding includes a plurality of secondary-side first winding portions and a plurality of secondary-side second winding portions, each of which is annular when viewed in the first direction. The plurality of primary-side first winding portions and the plurality of secondary-side first winding portions are alternately arranged in the first direction to form a first cylindrical portion. The plurality of primary-side second winding portions and the plurality of secondary-side second winding portions are alternately arranged in the first direction to form a second cylindrical portion. The second cylindrical portion is located inside the first cylindrical portion when viewed in the first direction. The direction of the input current flowing through each of the plurality of primary-side first winding portions is the same as the direction of the input current flowing through each of the plurality of primary-side second winding portions.

[0007] A coil component provided by a second aspect of the present disclosure includes a winding that generates a magnetic field by an external input current. The winding includes a plurality of first winding portions and a plurality of second winding portions, each of which is annular when viewed in a first direction. The plurality of first winding portions are arranged in the first direction to form a first cylindrical portion. The plurality of second winding portions are arranged in the first direction to form a second cylindrical portion. The second cylindrical portion is located inside the first cylindrical portion when viewed in the first direction. The first cylindrical portion and the second cylindrical portion are each annular when viewed in a thickness direction perpendicular to the first direction. The direction of the input current flowing in each of the plurality of first winding portions and the direction of the input current flowing in each of the plurality of second winding portions are the same.

[0008] A coil-embedded substrate provided by a third aspect of the present disclosure incorporates the coil component provided by the first aspect or the coil component provided by the second aspect. The coil-embedded substrate includes a plurality of wiring layers stacked in the thickness direction and a plurality of insulating layers interposed between the plurality of wiring layers in the thickness direction. The coil component is constituted by wiring patterns in the plurality of wiring layers. [Effects of the Invention]

[0009] The coil component and coil-built-in substrate of the present disclosure can suppress magnetic flux leakage. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing a coil component according to a first embodiment. [Figure 2] FIG. 2 is a partially enlarged view of a part of FIG. [Figure 3] FIG. 1 is a plan view showing a coil component according to a first embodiment. [Figure 4] FIG. 4 is a cross-sectional end view taken along line IV-IV in FIG. 3. [Figure 5] 1, taken along the cross section of FIG. 4 (a cross section taken along line IV-IV in FIG. 3). [Figure 6] FIG. 2 is a bottom view showing the coil component according to the first embodiment. [Figure 7] 2 is a perspective view of FIG. 1 with a portion (part of the first cylindrical portion) omitted. [Figure 8] FIG. 2 is a perspective view showing a primary winding of the coil component according to the first embodiment. [Figure 9] FIG. 2 is a plan view showing a primary winding of the coil component according to the first embodiment. [Figure 10] FIG. 10 is a schematic diagram of the primary winding shown in FIGS. 8 and 9 as viewed in the circumferential direction. [Figure 11] FIG. 2 is a perspective view showing a secondary winding of the coil component according to the first embodiment. [Figure 12] FIG. 2 is a plan view showing a secondary winding of the coil component according to the first embodiment. [Figure 13] 13 is a schematic diagram of the secondary winding of FIGS. 11 and 12 as viewed in the circumferential direction. FIG. [Figure 14] 3 is a schematic diagram showing a part of a primary winding and a secondary winding, illustrating an example of connection of each connection portion. FIG. [Figure 15]FIG. 1 is a perspective view showing a coil-embedded substrate according to a first embodiment. [Figure 16] FIG. 1 is a plan view showing a coil-embedded substrate according to a first embodiment. [Figure 17] FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. [Figure 18] FIG. 10 is a perspective view showing a coil component according to a second embodiment. [Figure 19] FIG. 19 is a partially enlarged view of a part of FIG. 18. [Figure 20] FIG. 10 is a plan view showing a coil component according to a second embodiment. [Figure 21] FIG. 21 is a cross-sectional end view taken along line XXI-XXI in FIG. 20. [Figure 22] FIG. 10 is a bottom view showing the coil component according to the second embodiment. [Figure 23] 19 is a perspective view of FIG. 18 with a portion (part of the first cylindrical portion) omitted. [Figure 24] FIG. 10 is a schematic diagram of the windings of the coil component according to the second embodiment as viewed in the circumferential direction. [Figure 25] FIG. 10 is a perspective view showing a coil-embedded substrate according to a second embodiment. [Figure 26] FIG. 10 is a plan view showing a coil-embedded substrate according to a second embodiment. [Figure 27] FIG. 27 is a cross-sectional view taken along line XXVII-XXVII in FIG. 26. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the coil component and the coil-embedded substrate of the present disclosure will be described below with reference to the drawings. In the following description, identical or similar components will be designated by the same reference numerals, and redundant description will be omitted.

[0012] A coil component A1 according to a first embodiment will be described with reference to FIGS. 1 to 14. The coil component A1 is, for example, a transformer and includes a primary winding 1 and a secondary winding 2. The coil component A1 may include a magnetic core, but is preferably an air-core coil without a magnetic core. The coil component A1 has, for example, a toroidal shape in appearance. The planar shape of the coil component A1 is preferably a substantially circular ring, such as a circular ring, an elliptical ring, or a polygonal ring. Note that the planar shape of the coil component A1 does not necessarily have to be a circular ring. The cross-sectional shape of the coil component A1 is preferably a substantially circular ring, such as a circular ring, an elliptical ring, or a polygonal ring. The overall shape of the coil component A1 can be configured by various combinations of the above planar shape and the above cross-sectional shape. In the first embodiment, a case where the planar shape is a circular ring and the cross-sectional shape is a rectangular ring will be described as an example. For ease of explanation, in a plan view of the coil component A1, the direction in which the central axis extends is referred to as the axial direction s, the direction around the central axis as the circumferential direction t, and the direction extending radially from the central axis as the radial direction u. The axial direction s corresponds to the thickness direction of the coil component A1. The circumferential direction t coincides with the toroidal direction of the coil component A1. Furthermore, the above cross-sectional shape corresponds to a cross section in a plane defined by the axial direction s and the radial direction u. The circumferential direction t corresponds to the "first direction," and the axial direction s corresponds to the "thickness direction."

[0013] FIG. 1 is a perspective view showing the coil device A1. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 3 is a plan view showing the coil device A1. FIG. 4 is a cross-sectional end view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view of the perspective view shown in FIG. 1 taken along the cross section of FIG. 4 (a cross section taken along line IV-IV in FIG. 3). In FIG. 5, the cross-sectional portion is indicated by an imaginary line (a two-dot chain line). FIG. 6 is a bottom view showing the coil device A1. FIG. 7 is a cross-sectional view of the perspective view shown in FIG. 1 with a portion (a portion of a first cylindrical portion 5A described below) omitted. FIG. 8 is a perspective view showing the primary winding 1 of the coil device A1. FIG. 9 is a plan view showing the primary winding 1 of the coil device A1. FIG. 10 is a schematic view of the primary winding 1 shown in FIGS. 8 and 9 when viewed along the circumferential direction t. FIG. 11 is a perspective view showing the secondary winding 2 of the coil device A1. FIG. 12 is a plan view showing the secondary winding 2 of the coil device A1. FIG. 13 is a schematic view of the secondary winding 2 of FIGS. 11 and 12 when viewed along the circumferential direction t. FIG. 14 is a schematic view showing a portion of the primary winding 1 and the secondary winding 2, illustrating an example of a connection portion 13 (described later) and a connection portion 23 (described later). Note that the connection portions 13 and 23 are omitted in FIGS. 1 to 13. FIG. 14(a) is a view viewed from the outside in the radial direction u to the inside in the radial direction u, FIGS. 14(b) and 14(c) are views viewed from both sides in the circumferential direction t, and FIGS. 14(d) and 14(e) are views viewed from both sides in the axial direction s.

[0014] The coil component A1 has a primary winding 1 and a secondary winding 2 wound alternately and doubly. The coil component A1 includes a first cylindrical portion 5A and a second cylindrical portion 5B formed by doubly winding the primary winding 1 and the secondary winding 2. The first cylindrical portion 5A and the second cylindrical portion 5B each have a toroidal shape. As shown in FIG. 7, the second cylindrical portion 5B is located inside the first cylindrical portion 5A. The first cylindrical portion 5A forms the outer appearance of the coil component A1. The first cylindrical portion 5A and the second cylindrical portion 5B each have a planar shape, for example, a circular ring shape, and share a common central axis. That is, the central axis of the first cylindrical portion 5A in a planar view and the central axis of the second cylindrical portion 5B in a planar view are substantially the same. The direction in which this central axis extends corresponds to the axial direction s. Furthermore, the first cylindrical portion 5A and the second cylindrical portion 5B each have a cross-sectional shape, for example, a rectangular ring shape.

[0015] The primary winding 1 generates a magnetic field by an external input current. As shown in Figures 8 to 10 and 14, the primary winding 1 includes a plurality of first winding portions 11, a plurality of second winding portions 12, and a connection portion 13. The first winding portion 11 corresponds to the "primary-side first winding portion," the second winding portion 12 corresponds to the "primary-side second winding portion," and the connection portion 13 corresponds to the "primary-side connection portion."

[0016] As shown in FIG. 10 , each of the multiple first winding portions 11 has a shape, for example, a rectangular ring when viewed in the circumferential direction t. As shown in FIG. 9 , the multiple first winding portions 11 are lined up in the circumferential direction t when viewed in the axial direction s. The multiple first winding portions 11 are part of the first tubular portion 5A. As shown in FIG. 10 , each of the multiple first winding portions 11 includes a first upper conductor portion 111, a first lower conductor portion 112, and a pair of first connecting conductor portions 113 and 114. The first upper conductor portion 111 corresponds to the "primary-side first upper conductor portion," the first lower conductor portion 112 corresponds to the "primary-side first lower conductor portion," and the pair of first connecting conductor portions 113 and 114 correspond to the "pair of primary-side first connecting conductor portions."

[0017] In each first winding portion 11, the first upper conductor portion 111 and the first lower conductor portion 112 are spaced apart in the axial direction s, as shown in FIG. 10 . As shown in FIG. 9 , the first upper conductor portion 111 and the first lower conductor portion 112 each extend from the inner peripheral edge 51A of the first cylindrical portion 5A toward the outer peripheral edge 52A of the first cylindrical portion 5A when viewed in the axial direction s. The first upper conductor portion 111 and the first lower conductor portion 112 each have a strip shape when viewed in the axial direction s. As shown in FIG. 10 , the pair of first connecting conductor portions 113 and 114 each extend from the first upper conductor portion 111 along the axial direction s. The first connecting conductor portion 113 is connected to the first lower conductor portion 112 of the same first winding portion 11. The first connecting conductor portion 114 is connected to the first lower conductor portion 112 of the first winding portion 11 adjacent to it in the circumferential direction t. The pair of first connecting conductors 113, 114 are each approximately perpendicular to the first upper conductor 111 and the first lower conductor 112. When viewed in the axial direction s, the first connecting conductor 113 overlaps the inner peripheral edge 51A of the first tubular portion 5A, and the first connecting conductor 114 overlaps the outer peripheral edge 52A of the first tubular portion 5A. When viewed along the radial direction u, the pair of first connecting conductors 113, 114 each have a band shape extending in the axial direction s.

[0018] In this embodiment, each first upper conductor 111 is inclined in one direction in the circumferential direction t with respect to the radial direction u, and each first lower conductor 112 is inclined in the other direction in the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 9 , the radial direction u overlapping each first connecting conductor 113 is defined as the radial direction u11, and the first upper conductor 111 connected to the first connecting conductor 113 is inclined clockwise in the circumferential direction t with respect to the radial direction u11. Furthermore, the first lower conductor 112 connected to the first connecting conductor 113 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u11. In this way, the first upper conductor 111 and the first lower conductor 112 are inclined in opposite directions in the circumferential direction t with respect to the radial direction u, so that a pair of first connecting conductors 113, 114 can each be formed along the axial direction s.

[0019] In this embodiment, two first upper conductors 111 adjacent to each other in the circumferential direction t and two first lower conductors 112 adjacent to each other in the circumferential direction t are disposed at a predetermined interval. The interval is, for example, substantially the same on the inner peripheral edge 51A side and the outer peripheral edge 52A side of the first tubular portion 5A. With this configuration, the dimension of the first connecting conductor 114 along the circumferential direction t is greater than the dimension of the first connecting conductor 113 along the circumferential direction t when viewed in the axial direction s.

[0020] Among the multiple first winding portions 11, two adjacent first winding portions 11 in the circumferential direction t are directly connected to each other, and the input current flowing through the primary winding 1 flows sequentially through the multiple first winding portions 11. At this time, the input current is transmitted to the first connecting conductor portion 114 of each first winding portion 11 from the first lower conductor portion 112 of the first winding portion 11 adjacent to one side in the circumferential direction t. This input current then flows from the first connecting conductor portion 114 to the first lower conductor portion 112 via the first upper conductor portion 111 and the first connecting conductor portion 113. That is, in the example shown in FIG. 10 , the input current flowing through each first winding portion 11 flows counterclockwise. Then, it is transmitted to the adjacent first winding portion 11 on the other side in the circumferential direction t. In this way, the input current of the primary winding 1 circulates through each of the multiple first winding portions 11. Note that the direction of the input current flowing through the first winding portions 11 may be opposite to that in the above example. That is, the first lower conductor portion 112 of each first winding portion 11 receives the input current from the first connecting conductor portion 114 of the first winding portion 11 adjacent to it on the other side in the circumferential direction t. This input current then flows from the first lower conductor portion 112 to the first connecting conductor portion 114 via the first connecting conductor portion 113 and the first upper conductor portion 111. That is, in the example shown in FIG. 10 , the input current flowing in each first winding portion 11 may flow clockwise.

[0021] As shown in FIG. 10 , each of the multiple second winding portions 12 has a shape, for example, a rectangular ring shape when viewed in the circumferential direction t. As shown in FIG. 10 , each second winding portion 12 is located inward of each first winding portion 11 when viewed in the circumferential direction t. As shown in FIG. 9 , the multiple second winding portions 12 are lined up in the circumferential direction t when viewed in the axial direction s. The second winding portion 12 is part of the second tubular portion 5B. As shown in FIGS. 8 and 9 , the multiple first winding portions 11 and the multiple second winding portions 12 are alternately arranged in the circumferential direction t when viewed in the axial direction s. As shown in FIG. 10 , each of the multiple second winding portions 12 includes a second upper conductor portion 121, a second lower conductor portion 122, and a pair of second connection conductor portions 123 and 124. The second upper conductor portion 121 corresponds to the "primary side second upper conductor portion," the second lower conductor portion 122 corresponds to the "primary side second lower conductor portion," and the pair of second connecting conductor portions 123, 124 correspond to the "pair of primary side second connecting conductor portions."

[0022] In each second winding portion 12, the second upper conductor 121 and the second lower conductor 122 are spaced apart in the axial direction s, as shown in FIG. 10 . As shown in FIG. 9 , the second upper conductor 121 and the second lower conductor 122 each extend from the inner circumferential edge 51B of the second cylindrical portion 5B toward the outer circumferential edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. The second upper conductor 121 and the second lower conductor 122 each have a strip shape when viewed in the axial direction s. As shown in FIG. 10 , the pair of second connecting conductors 123 and 124 each extend from the second upper conductor 121 along the axial direction s. The second connecting conductor 123 is connected to the second lower conductor 122 of the same second winding portion 12. The second connecting conductor 124 is connected to the second lower conductor 122 of the second winding portion 12 adjacent to it in the circumferential direction t. The pair of second connection conductors 123, 124 are each approximately perpendicular to the second upper conductor 121 and the second lower conductor 122. The second connection conductor 123 overlaps the inner peripheral edge 51B of the second tubular portion 5B when viewed in the axial direction s, and the second connection conductor 124 overlaps the outer peripheral edge 52B of the second tubular portion 5B when viewed in the axial direction s. When viewed along the radial direction u, the pair of second connection conductors 123, 124 each have a band shape extending in the axial direction s.

[0023] In this embodiment, each second upper conductor 121 is inclined to one side of the circumferential direction t with respect to the radial direction u, and each second lower conductor 122 is inclined to the other side of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 9 , the radial direction u overlapping each second connection conductor 123 is defined as the radial direction u12, and the second upper conductor 121 connected to the second connection conductor 123 is inclined clockwise in the circumferential direction t with respect to the radial direction u12. Furthermore, the second lower conductor 122 connected to the second connection conductor 123 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u12. In this way, the second upper conductor 121 and the second lower conductor 122 are inclined to the opposite side of the circumferential direction t with respect to the radial direction u, so that a pair of second connection conductors 123, 124 can each be formed along the axial direction s.

[0024] In this embodiment, two second upper conductors 121 adjacent to each other in the circumferential direction t and two second lower conductors 122 adjacent to each other in the circumferential direction t are disposed at a predetermined interval. The interval is, for example, substantially the same on the inner peripheral edge 51B side and the outer peripheral edge 52B side of the second cylindrical portion 5B. With this configuration, the dimension of the second connecting conductor 124 along the circumferential direction t is greater than the dimension of the second connecting conductor 123 along the circumferential direction t when viewed in the axial direction s.

[0025] Among the multiple second winding parts 12, two adjacent second winding parts 12 in the circumferential direction t are directly connected to each other, and the input current flowing through the primary winding 1 flows sequentially through the multiple second winding parts 12. At this time, the input current is transmitted to the second connecting conductor 124 of each second winding part 12 from the second lower conductor 122 of the second winding part 12 adjacent to it on one side in the circumferential direction t. This input current then flows from the second connecting conductor 124 to the second lower conductor 122 via the second upper conductor 121 and the second connecting conductor 123. That is, in the example shown in FIG. 10 , the input current flowing through each second winding part 12 flows counterclockwise. Therefore, the direction of the input current flowing through each first winding part 11 and the direction of the input current flowing through each second winding part 12 are the same when viewed along the circumferential direction t. In this way, the input current to the primary winding 1 circulates through each of the multiple second winding portions 12. Note that the direction of the input current flowing through the second winding portions 12 may be opposite to that in the above example. That is, the second lower conductor portion 122 of each second winding portion 12 receives the input current from the second connecting conductor portion 124 of the second winding portion 12 adjacent to it on the other side in the circumferential direction t. This input current then flows from the second lower conductor portion 122 to the second connecting conductor portion 124 via the second connecting conductor portion 123 and the second upper conductor portion 121. That is, in the example shown in FIG. 10 , the input current flowing through each second winding portion 12 may be configured to flow clockwise. However, the direction of the input current flowing through each first winding portion 11 and the direction of the input current flowing through each second winding portion 12 should be the same when viewed along the circumferential direction t.

[0026] The connection portion 13 connects one of the multiple first winding portions 11 and one of the multiple second winding portions 12. For example, as shown in Fig. 14, the connection portion 13 is connected to a first lower conductor portion 112 of one of the multiple first winding portions 11 and a second upper conductor portion 121 of one of the multiple second winding portions 12, thereby establishing electrical continuity between them.

[0027] The primary winding 1 has a plurality of first winding portions 11 connected in series along the circumferential direction t, and a plurality of second winding portions 12 connected in series along the circumferential direction t. These are connected by connecting portions 13. Therefore, the input current of the primary winding 1 flows around the plurality of first winding portions 11, then is input to the plurality of second winding portions 12 via the connecting portions 13, and flows around the plurality of second winding portions 12.

[0028] An induced current flows in the secondary winding 2 due to the influence of the magnetic field generated by the primary winding 1. As shown in FIGS. 11 to 14, the secondary winding 2 includes a plurality of first winding portions 21, a plurality of second winding portions 22, and a connecting portion 23. The first winding portion 21 corresponds to the "secondary-side first winding portion," the second winding portion 22 corresponds to the "secondary-side second winding portion," and the connecting portion 23 corresponds to the "secondary-side connecting portion."

[0029] As shown in Fig. 13, each of the multiple first winding portions 21 has a shape, for example, a rectangular ring when viewed in the circumferential direction t. As shown in Fig. 12, the multiple first winding portions 21 are lined up in the circumferential direction t when viewed in the axial direction s. The multiple first winding portions 21 are part of the first tubular portion 5A. Each of the multiple first winding portions 21 includes a first upper conductor portion 211, a first lower conductor portion 212, and a pair of first connecting conductor portions 213, 214. The first upper conductor portion 211 corresponds to the "secondary-side first upper conductor portion," the first lower conductor portion 212 corresponds to the "secondary-side first lower conductor portion," and the pair of first connecting conductor portions 213, 214 correspond to the "pair of secondary-side first connecting conductor portions."

[0030] In each first winding portion 21, the first upper conductor portion 211 and the first lower conductor portion 212 are spaced apart in the axial direction s, as shown in FIG. 13 . As shown in FIG. 12 , the first upper conductor portion 211 and the first lower conductor portion 212 each extend from the inner circumferential edge 51A of the first cylindrical portion 5A toward the outer circumferential edge 52A of the first cylindrical portion 5A when viewed in the axial direction s. The first upper conductor portion 211 and the first lower conductor portion 212 each have a strip shape when viewed in the axial direction s. As shown in FIG. 13 , the pair of first connecting conductor portions 213, 214 each extend from the first upper conductor portion 211 along the axial direction s. The first connecting conductor portion 213 is connected to the first lower conductor portion 212 of the same first winding portion 21. The first connecting conductor portion 214 is connected to the first lower conductor portion 212 of the first winding portion 21 adjacent to it in the circumferential direction t. The pair of first connecting conductors 213, 214 are each approximately perpendicular to the first upper conductor 211 and the first lower conductor 212. The first connecting conductor 213 overlaps the inner peripheral edge 51A of the first tubular portion 5A when viewed in the axial direction s, and the first connecting conductor 214 overlaps the outer peripheral edge 52A of the first tubular portion 5A when viewed in the axial direction s. When viewed along the radial direction u, the pair of first connecting conductors 213, 214 each have a band shape extending in the axial direction s.

[0031] In this embodiment, each first upper conductor 211 is inclined to one side of the circumferential direction t with respect to the radial direction u, and each first lower conductor 212 is inclined to the other side of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 12 , the radial direction u overlapping each first connecting conductor 213 is defined as the radial direction u21, and the first upper conductor 211 connected to the first connecting conductor 213 is inclined clockwise in the circumferential direction t with respect to the radial direction u21. Furthermore, the first lower conductor 212 connected to the first connecting conductor 213 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u21. In this way, the first upper conductor 211 and the first lower conductor 212 are inclined to opposite sides of the circumferential direction t with respect to the radial direction u, so that the pair of first connecting conductors 213, 214 can each be formed along the axial direction s.

[0032] In this embodiment, two first upper conductors 211 adjacent to each other in the circumferential direction t and two first lower conductors 212 adjacent to each other in the circumferential direction t are disposed at a predetermined interval. The interval is, for example, substantially the same on the inner peripheral edge 51A side and the outer peripheral edge 52A side. With this configuration, the dimension of the first connecting conductor 214 along the circumferential direction t is greater than the dimension of the first connecting conductor 213 along the circumferential direction t when viewed in the axial direction s.

[0033] Among the multiple first winding portions 21, two adjacent first winding portions 21 in the circumferential direction t are directly connected to each other, and the induced current flowing in the secondary winding 2 flows sequentially through the multiple first winding portions 21. At this time, the induced current is transmitted to the first connecting conductor portion 214 of each first winding portion 21 from the first lower conductor portion 212 of the first winding portion 21 adjacent to it on one side in the circumferential direction t. This induced current then flows from the first connecting conductor portion 214 to the first lower conductor portion 212 via the first upper conductor portion 211 and the first connecting conductor portion 213. That is, in the example shown in FIG. 13 , the induced current flowing in each first winding portion 21 flows counterclockwise. Then, it is transmitted to the adjacent first winding portion 21 on the other side in the circumferential direction t. In this way, the induced current in the secondary winding 2 makes a circuit through each of the multiple first winding portions 21. Note that the direction of the induced current flowing in the first winding portion 21 may be opposite to that in the above example. That is, the first lower conductor portion 212 of each first winding portion 21 receives an induced current from the first connecting conductor portion 214 of the first winding portion 21 adjacent to it on the other side in the circumferential direction t. This induced current flows from the first lower conductor portion 212 to the first connecting conductor portion 214 via the first connecting conductor portion 213 and the first upper conductor portion 211. That is, in the example shown in FIG. 13 , the induced current flowing in each first winding portion 21 may flow clockwise. The direction of the induced current flowing in each first winding portion 21 is determined by the magnetic field generated by the primary winding 1.

[0034] As shown in FIG. 13 , each of the multiple second winding portions 22 has a shape, for example, a rectangular ring shape when viewed in the circumferential direction t. As shown in FIG. 13 , each second winding portion 22 is located inward of each first winding portion 21 when viewed in the circumferential direction t. As shown in FIG. 12 , the multiple second winding portions 22 are aligned in the circumferential direction t when viewed in the axial direction s. The second winding portion 22 is a part of the second tubular portion 5B. As shown in FIGS. 11 and 12 , the multiple first winding portions 21 and the multiple second winding portions 22 are alternately arranged in the circumferential direction t when viewed in the axial direction s. As shown in FIG. 13 , each of the multiple second winding portions 22 includes a second upper conductor portion 221, a second lower conductor portion 222, and a pair of second connection conductor portions 223 and 224. The second upper conductor portion 221 corresponds to the "secondary side second upper conductor portion", the second lower conductor portion 222 corresponds to the "secondary side second lower conductor portion", and the pair of second connecting conductor portions 223, 224 correspond to the "pair of secondary side second connecting conductor portions".

[0035] In each second winding portion 22, the second upper conductor 221 and the second lower conductor 222 are spaced apart in the axial direction s, as shown in FIG. 13 . As shown in FIG. 12 , the second upper conductor 221 and the second lower conductor 222 each extend from the inner circumferential edge 51B of the second cylindrical portion 5B toward the outer circumferential edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. The second upper conductor 221 and the second lower conductor 222 each have a strip shape when viewed in the axial direction s. As shown in FIG. 13 , the pair of second connecting conductors 223, 224 each extend from the second upper conductor 221 along the axial direction s. The second connecting conductor 223 is connected to the second lower conductor 222 of the same second winding portion 22. The second connecting conductor 224 is connected to the second lower conductor 222 of the second winding portion 22 adjacent to it in the circumferential direction t. The pair of second connection conductors 223, 224 are each approximately perpendicular to the second upper conductor 221 and the second lower conductor 222. The second connection conductor 223 overlaps the inner peripheral edge 51B of the second tubular portion 5B when viewed in the axial direction s, and the second connection conductor 224 overlaps the outer peripheral edge 52B of the second tubular portion 5B when viewed in the axial direction s. When viewed along the radial direction u, the pair of second connection conductors 223, 224 each have a belt shape extending in the axial direction s.

[0036] In this embodiment, each second upper conductor 221 is inclined to one side of the circumferential direction t with respect to the radial direction u, and each second lower conductor 222 is inclined to the other side of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 12 , the radial direction u overlapping each second connecting conductor 223 is defined as the radial direction u22, and the second upper conductor 221 connected to the second connecting conductor 223 is inclined clockwise in the circumferential direction t with respect to the radial direction u22. Furthermore, the second lower conductor 222 connected to the second connecting conductor 223 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u22. In this way, the second upper conductor 221 and the second lower conductor 222 are inclined to the opposite side of the circumferential direction t with respect to the radial direction u, so that a pair of second connecting conductors 223, 224 can each be formed along the axial direction s.

[0037] In this embodiment, two second upper conductors 221 adjacent to each other in the circumferential direction t and two second lower conductors 222 adjacent to each other in the circumferential direction t are disposed at a predetermined interval. The interval is, for example, substantially the same on the inner peripheral edge 51B side and the outer peripheral edge 52B side. With this configuration, the dimension of the second connecting conductor 224 along the circumferential direction t is greater than the dimension of the second connecting conductor 223 along the circumferential direction t when viewed in the axial direction s.

[0038] Among the multiple second winding portions 22, two adjacent second winding portions 22 in the circumferential direction t are directly connected to each other, and the induced current flowing in the secondary winding 2 flows sequentially through the multiple second winding portions 22. At this time, the induced current is transmitted to the second connecting conductor 224 of each second winding portion 22 from the second lower conductor 222 of the second winding portion 22 adjacent to it on one side in the circumferential direction t. This induced current then flows from the second connecting conductor 224 to the second lower conductor 222 via the second upper conductor 221 and the second connecting conductor 223. That is, in the example shown in FIG. 13 , the induced current flowing in each second winding portion 22 flows counterclockwise. Therefore, the direction of the induced current flowing in each first winding portion 21 and the direction of the induced current flowing in each second winding portion 22 are the same when viewed along the circumferential direction t. In this way, the induced current in the secondary winding 2 circulates around each of the multiple second winding portions 22. The direction of the induced current flowing through the second winding portions 22 may be opposite to that in the above example. That is, the second lower conductor portion 222 of each second winding portion 22 receives the induced current from the second connecting conductor portion 224 of the second winding portion 22 adjacent to it on the other side in the circumferential direction t. This induced current then flows from the second lower conductor portion 222 to the second connecting conductor portion 224 via the second connecting conductor portion 223 and the second upper conductor portion 221. That is, in the example shown in FIG. 13 , the induced current flowing through each second winding portion 22 may be configured to flow clockwise. However, the direction of the induced current flowing through each first winding portion 21 and the direction of the induced current flowing through each second winding portion 22 are the same when viewed along the circumferential direction t.

[0039] The connection portion 23 connects one of the multiple first winding portions 21 and one of the multiple second winding portions 22. For example, as shown in Fig. 14, the connection portion 23 is connected to a first upper conductor portion 211 of one of the multiple first winding portions 21 and a second lower conductor portion 222 of one of the multiple second winding portions 22, thereby establishing electrical continuity between them.

[0040] In the secondary winding 2, a plurality of first winding portions 21 are connected in series along the circumferential direction t, and a plurality of second winding portions 22 are connected in series along the circumferential direction t. These are connected by connecting portions 23. Therefore, the induced current of the secondary winding 2 flows around the plurality of first winding portions 21, and then is input to the plurality of second winding portions 22 via the connecting portions 23, and flows around the plurality of second winding portions 22.

[0041] In the coil component A1, a plurality of first winding portions 11 (primary winding 1) and a plurality of first winding portions 21 (secondary winding 2) are alternately arranged in the circumferential direction t to form a first cylindrical portion 5A. Also, a plurality of second winding portions 12 (primary winding 1) and a plurality of second winding portions 22 (secondary winding 2) are alternately arranged in the circumferential direction t to form a second cylindrical portion 5B. The second cylindrical portion 5B is located inside the first cylindrical portion 5A.

[0042] 3 to 7, in the coil component A1, the first winding portions 11 of the primary winding 1 and the first winding portions 21 of the secondary winding 2 overlap each other when viewed along the circumferential direction t. That is, when viewed along the circumferential direction t, the first upper conductor portions 111 and the first upper conductor portions 211 overlap each other, the first lower conductor portions 112 and the first lower conductor portions 212 overlap each other, the first connecting conductor portions 113 and the first connecting conductor portions 213 overlap each other, and the first connecting conductor portions 114 and the first connecting conductor portions 214 overlap each other. Also, as shown in FIGS. 3 to 7, the second winding portions 12 of the primary winding 1 and the second winding portions 22 of the secondary winding 2 overlap each other when viewed along the circumferential direction t. In other words, when viewed along the circumferential direction t, each second upper conductor portion 121 overlaps with each second upper conductor portion 221, each second lower conductor portion 122 overlaps with each second lower conductor portion 222, each second connecting conductor portion 123 overlaps with each second connecting conductor portion 223, and each second connecting conductor portion 124 overlaps with each second connecting conductor portion 224.

[0043] In the coil component A1, as shown in FIGS. 3 to 7, the first winding portions 11 of the primary winding 1 and the second winding portions 22 of the secondary winding 2 partially overlap when viewed in the axial direction s and also partially overlap when viewed in the radial direction u. That is, when viewed in the axial direction s, the first upper conductor portions 111 and the second upper conductor portions 221 overlap with each other, and the first lower conductor portions 112 and the second lower conductor portions 222 overlap with each other. When viewed in the radial direction u, the first connecting conductor portions 113 and the second connecting conductor portions 223 overlap with each other, and the first connecting conductor portions 114 and the second connecting conductor portions 224 overlap with each other. Furthermore, as shown in FIGS. 3 to 7, the second winding portions 12 of the primary winding 1 and the first winding portions 21 of the secondary winding 2 partially overlap when viewed in the axial direction s and also partially overlap when viewed in the radial direction u. That is, when viewed in the axial direction s, the second upper conductors 121 and the first upper conductors 211 overlap each other, and the second lower conductors 122 and the first lower conductors 212 overlap each other. When viewed in the radial direction u, the second connecting conductors 123 and the first connecting conductors 213 overlap each other, and the second connecting conductors 124 and the first connecting conductors 214 overlap each other.

[0044] Next, the coil-built-in substrate B1 incorporating the coil component A1 will be described with reference to Figs. 15 to 17. Fig. 15 is a perspective view showing the coil-built-in substrate B1. Fig. 16 is a plan view showing the coil-built-in substrate B1. Fig. 17 is a cross-sectional view taken along line XVII-XVII in Fig. 16.

[0045] The coil-built-in substrate B1 is, for example, a printed circuit board. The coil-built-in substrate B1 is not limited to a printed circuit board and may be a semiconductor substrate or a ceramic substrate. The coil-built-in substrate B1 has a built-in coil component A1. The coil-built-in substrate B1 is, for example, rectangular in plan view. The coil-built-in substrate B1 includes a plurality of wiring layers 7, a plurality of through electrodes 79, an insulating member 8, and a plurality of terminals 9A and 9B.

[0046] Each of the multiple wiring layers 7 is made of, for example, a metal. The constituent material of each wiring layer 7 is, for example, Cu (copper) or a Cu alloy. The constituent material is not limited to Cu or a Cu alloy. The multiple wiring layers 7 include a first wiring layer 71, a second wiring layer 72, a third wiring layer 73, and a fourth wiring layer 74.

[0047] The first wiring layer 71, the second wiring layer 72, the third wiring layer 73, and the fourth wiring layer 74 are stacked from one side (upper side in FIG. 17) to the other side (lower side in FIG. 17) in the axial direction s and are spaced apart from each other. Wiring patterns are formed on the first wiring layer 71, the second wiring layer 72, the third wiring layer 73, and the fourth wiring layer 74, respectively.

[0048] The wiring pattern in the first wiring layer 71 forms a plurality of first upper conductor portions 111 (first winding portions 11 of the primary winding 1) and a plurality of first upper conductor portions 211 (first winding portions 21 of the secondary winding 2).

[0049] The wiring pattern in the second wiring layer 72 forms a plurality of second upper conductor portions 121 (second winding portions 12 of the primary winding 1) and a plurality of second upper conductor portions 221 (second winding portions 22 of the secondary winding 2).

[0050] The wiring pattern in the third wiring layer 73 forms a plurality of second lower conductor portions 122 (second winding portions 12 of the primary winding 1) and a plurality of second lower conductor portions 222 (second winding portions 22 of the secondary winding 2).

[0051] The wiring pattern in the fourth wiring layer 74 forms a plurality of first lower conductor portions 112 (first winding portions 11 of the primary winding 1) and a plurality of first lower conductor portions 212 (first winding portions 21 of the secondary winding 2).

[0052] 17, the separation distance in the axial direction s between the first wiring layer 71 and the second wiring layer 72 is approximately the same as the separation distance in the axial direction s between the third wiring layer 73 and the fourth wiring layer 74. Furthermore, the separation distance in the axial direction s between the second wiring layer 72 and the third wiring layer 73 is greater than the separation distance in the axial direction s between the first wiring layer 71 and the second wiring layer 72 and the separation distance in the axial direction s between the third wiring layer 73 and the fourth wiring layer 74. As a result, in the primary winding 1 of the coil component A1, the separation distance in the axial direction s between the first upper conductor 111 and the second upper conductor 121 is approximately the same as the separation distance in the axial direction s between the second lower conductor 122 and the first lower conductor 112. Furthermore, the separation distance in the axial direction s between the second upper conductor 121 and the second lower conductor 122 is greater than the separation distance in the axial direction s between the first upper conductor 111 and the second upper conductor 121 and the separation distance in the axial direction s between the second lower conductor 122 and the first lower conductor 112. The same is true for the secondary winding 2 of the coil component A1.

[0053] The plurality of through electrodes 79 partially penetrate the insulating member 8 in the axial direction s. In this embodiment, each through electrode 79 is, for example, columnar. The plurality of through electrodes 79 include one that electrically connects the first wiring layer 71 and the fourth wiring layer 74 and one that electrically connects the second wiring layer 72 and the third wiring layer 73. The through electrodes 79 that electrically connect the first wiring layer 71 and the fourth wiring layer 74 form a pair of first connection conductors 113, 114 (first winding portion 11 of the primary winding 1) and a pair of first connection conductors 213, 214 (first winding portion 21 of the secondary winding 2). The through electrodes 79 that electrically connect the second wiring layer 72 and the third wiring layer 73 form a pair of second connection conductors 123, 124 (second winding portion 12 of the primary winding 1) and a pair of second connection conductors 223, 224 (second winding portion 22 of the secondary winding 2).

[0054] In the coil-built-in substrate B1, the wiring patterns of the plurality of wiring layers 7 (first wiring layer 71, second wiring layer 72, third wiring layer 73, fourth wiring layer 74) and the plurality of through electrodes 79 form a coil component A1.

[0055] As shown in Figs. 15 to 17, the insulating member 8 covers the coil component A1. The constituent material of the insulating member 8 is, for example, an insulating resin such as glass epoxy resin. The material of the insulating member 8 is not limited to insulating resin, and an insulating semiconductor material (for example, Si (silicon)) or ceramic may be used. Examples of the insulating treatment include doping with insulating impurities and forming an insulating oxide film.

[0056] 17, the insulating member 8 includes a plurality of insulating layers 81. As shown in Fig. 17, the plurality of insulating layers 81 include one interposed between the first wiring layer 71 and the second wiring layer 72 in the axial direction s, one interposed between the second wiring layer 72 and the third wiring layer 73 in the axial direction s, and one interposed between the third wiring layer 73 and the fourth wiring layer 74 in the axial direction s. The plurality of insulating layers 81 also includes one formed above the first wiring layer 71 (one side in the axial direction s) and one formed below the fourth wiring layer 74 (the other side in the axial direction s).

[0057] The pair of terminals 9A are electrically connected to the primary winding 1 and are input terminals for inputting an input current to the primary winding 1. Each of the pair of terminals 9A includes a portion formed outside the insulating member 8 and a terminal wiring portion 90A connected to this portion and the primary winding 1. The terminal wiring portion 90A of one of the terminals 9A is connected to the first upper conductor portion 111 (the first winding portion 11 of the primary winding 1), as shown by an imaginary line in FIG. 14, for example. The terminal wiring portion 90A of the other terminal 9A is connected to the second lower conductor portion 122 (the second winding portion 12 of the primary winding 1), as shown by an imaginary line in FIG. 14. When a voltage is applied between the pair of terminals 9A, an input current flows from one terminal 9A to the other terminal 9A via the primary winding 1. This generates a magnetic field from the primary winding 1.

[0058] The pair of terminals 9B are electrically connected to the secondary winding 2 and serve as output terminals for the induced current in the secondary winding 2. Each of the pair of terminals 9B includes a portion formed outside the insulating member 8 and a terminal wiring portion 90B connected to this portion and the secondary winding 2. The terminal wiring portion 90B of one of the terminals 9B is connected to the first lower conductor portion 212 (the first winding portion 21 of the secondary winding 2), as shown by imaginary lines in FIG. 14, for example. The terminal wiring portion 90B of the other terminal 9B is connected to the second upper conductor portion 221 (the second winding portion 22 of the secondary winding 2), as shown by imaginary lines in FIG. 14, for example. A magnetic field generated by the primary winding 1 generates an induced current in the secondary winding 2, generating a potential difference between the pair of terminals 9B.

[0059] 15 and 16, the pair of terminals 9A and the pair of terminals 9B are all formed so as to be exposed from the upper surface (the surface facing one side in the axial direction s) of the insulating member 8, but this is not limiting. Whether the pair of terminals 9A and the pair of terminals 9B are exposed from the upper surface of the insulating member 8 or from the lower surface (the surface facing the other side in the axial direction s) of the insulating member 8 can be changed as appropriate depending on the specifications of the coil-built-in substrate B1. In this case, the terminal wiring portion 90A of each terminal 9A and the terminal wiring portion 90B of each terminal 9B are changed as appropriate from the example shown in FIG.

[0060] The coil component A1 and the coil-built-in substrate B1 according to the first embodiment have the following advantages.

[0061] The coil component A1 has a primary winding 1 through which an input current flows from the outside. The primary winding 1 includes a plurality of first winding portions 11, each of which is annular when viewed in a first direction (circumferential direction t). With this configuration, the input current flows in opposite directions in the portions of each first winding portion 11 that face each other in the axial direction s. Therefore, the magnetic fluxes generated by these portions face in opposite directions outside each first winding portion 11 and cancel each other out. The plurality of first winding portions 11 are part of a first cylindrical portion 5A that forms the exterior of the coil component A1. Therefore, the magnetic flux outside each first winding portion 11 (first cylindrical portion 5A) of the coil component A1 is reduced, thereby suppressing magnetic flux leakage to the outside.

[0062] In the coil component A1, the primary winding 1 includes a plurality of first winding portions 11 and a plurality of second winding portions 12. The direction of the input current flowing through each of the plurality of first winding portions 11 and the direction of the input current flowing through each of the plurality of second winding portions 12 are the same when viewed in the first direction (circumferential direction t). With this configuration, the magnetic flux generated by the input current flowing through each of the first winding portions 11 and the magnetic flux generated by the input current flowing through each of the second winding portions 12 are oriented in the same direction inside the plurality of second winding portions 12, i.e., inside the second cylindrical portion 5B, and the two magnetic fluxes reinforce each other. Therefore, the coil component A1 can improve its inductance value because the magnetic flux inside the second cylindrical portion 5B increases.

[0063] Coil component A1 is an air-core type, with no magnetic cores provided for primary winding 1 and secondary winding 2. In coil components with magnetic cores, the magnetic cores can cause energy loss when the input current to primary winding 1 is in the high frequency band. Therefore, because coil component A1 does not have a magnetic core, energy loss due to the magnetic core can be suppressed even when the input current to primary winding 1 is in the high frequency band.

[0064] In the coil component A1, the multiple first winding portions 11 of the primary winding 1 and the multiple first winding portions 21 of the secondary winding 2 are arranged alternately in the circumferential direction t. Furthermore, the second winding portions 22 of the secondary winding 2 are arranged inside the first winding portions 11 of the primary winding 1, and the second winding portions 12 of the primary winding 1 are arranged inside the first winding portions 21 of the secondary winding 2. This configuration improves the coupling between the primary winding 1 and the secondary winding 2. This makes it possible to suppress magnetic flux leakage due to poor coupling between the primary winding 1 and the secondary winding 2.

[0065] The coil-built-in substrate B1 includes a plurality of wiring layers 7. The plurality of wiring layers 7 includes a first wiring layer 71, a second wiring layer 72, a third wiring layer 73, and a fourth wiring layer 74 stacked in the axial direction s. Wiring patterns are formed on each of the first wiring layer 71, the second wiring layer 72, the third wiring layer 73, and the fourth wiring layer 74, and these wiring patterns form the coil component A1. With this configuration, the coil component A1 is formed, for example, by a manufacturing process for a printed circuit board (or a semiconductor substrate or a ceramic substrate). Therefore, the coil-built-in substrate B1 facilitates the manufacture of the coil component A1, which has a complex wiring structure. Furthermore, because the coil component A1 is formed by wiring patterns on the plurality of wiring layers 7, the height of the coil component A1 can be reduced.

[0066] In the first embodiment, the first winding portions 11 of the primary winding 1 and the second winding portions 22 of the secondary winding 2 partially overlap when viewed in the axial direction s and partially overlap when viewed in the radial direction u. However, this is not limiting. For example, the first winding portions 11 of the primary winding 1 may partially overlap, when viewed in the axial direction s, with the second winding portions 12 of the primary winding 1, instead of with the second winding portions 22 of the secondary winding 2, and partially overlap when viewed in the radial direction u. In this case, the first winding portions 21 of the secondary winding 2 and the second winding portions 22 of the secondary winding 2 partially overlap when viewed in the axial direction s and partially overlap when viewed in the radial direction u. However, the coil device A1 is preferable to the coil device according to the modified example in terms of increasing the coupling coefficient between the primary winding 1 and the secondary winding 2.

[0067] In the first embodiment, an example has been described in which a plurality of first winding portions 11 connected continuously along the circumferential direction t and a plurality of second winding portions 12 connected continuously along the circumferential direction t are connected by the connection portions 13, but this is not limiting. For example, each first winding portion 11 and each second winding portion 12 adjacent to each other in the circumferential direction t may be connected. That is, the primary winding 1 may be configured such that an input current flows alternately between each first winding portion 11 and each second winding portion 12. Similarly, the secondary winding 2 may be configured such that an induced current flows alternately between each first winding portion 21 and each second winding portion 22.

[0068] In the first embodiment, an example has been described in which, in each first winding portion 11 (primary winding 1), the first upper conductor portion 111 is inclined to one side of the circumferential direction t with respect to the radial direction u, and the first lower conductor portion 112 is inclined to the other side of the circumferential direction t with respect to the radial direction u. However, this is not limiting. In each first winding portion 11, the first upper conductor portion 111 does not have to be inclined to one side of the circumferential direction t. In this case, the pair of first connecting conductor portions 113, 114 are shaped to extend along the axial direction s, so the inclination angle of the first lower conductor portion 112 in the circumferential direction t with respect to the radial direction u becomes large. Conversely, the first lower conductor portion 112 does not have to be inclined to the other side of the circumferential direction t. In this case, the pair of first connecting conductor portions 113, 114 are shaped to extend along the axial direction s, so the inclination angle of the first upper conductor portion 111 in the circumferential direction t with respect to the radial direction u becomes large. Furthermore, both the first upper conductor 111 and the first lower conductor 112 do not have to be inclined in the circumferential direction t. In this case, the pair of first connection conductors 113, 114 are inclined with respect to the axial direction s. This type of modification also applies to the second upper conductor 121 and the second lower conductor 122 in each second winding part 12 (primary winding 1), the first upper conductor 211 and the first lower conductor 212 in each first winding part 21 (secondary winding 2), and the second upper conductor 221 and the second lower conductor 222 in each second winding part 22 (secondary winding 2).

[0069] In the first embodiment, an example was shown in which, in each first winding portion 11 (primary winding 1), the dimension of the first connecting conductor 114 along the circumferential direction t is larger than the dimension of the first connecting conductor 113 along the circumferential direction t when viewed in the axial direction s. However, this is not limiting. These dimensions may be approximately the same. In this case, the predetermined gaps provided between two first upper conductors 111 adjacent to each other in the circumferential direction t and between two first lower conductors 112 adjacent to each other in the circumferential direction t are relatively larger on the side closer to the outer peripheral edge 52A and relatively smaller on the side closer to the inner peripheral edge 51A in the radial direction u. This modification also applies to the pair of second connecting conductors 123, 124 in each second winding portion 12 (primary winding 1), the pair of first connecting conductors 213, 214 in each first winding portion 21 (secondary winding 2), and the pair of second connecting conductors 223, 224 in each second winding portion 22 (secondary winding 2).

[0070] A coil component A2 according to the second embodiment will be described with reference to FIGS. 18 to 24. The coil component A2 is, for example, an inductor and includes a winding 3. The coil component A2 may include a magnetic core, but is preferably an air-core coil without a magnetic core. Like the coil component A1, the coil component A2 has, for example, a toroidal shape in appearance. Like the coil component A1, the overall shape of the coil component A2 can be configured by various combinations of the planar shape and the cross-sectional shape. In the second embodiment, however, an example will be described in which the planar shape is annular and the cross-sectional shape is rectangular. For convenience of explanation, in a plan view of the coil component A2, the direction in which the central axis extends is defined as the axial direction s, the direction around the central axis is defined as the circumferential direction t, and the direction extending radially from the central axis is defined as the radial direction u. The axial direction s corresponds to the thickness direction of the coil component A2. The circumferential direction t coincides with the toroidal direction of the coil component A2. The cross-sectional shape corresponds to a cross section in a plane defined by the axial direction s and the radial direction u.

[0071] FIG. 18 is a perspective view showing the coil device A2. FIG. 19 is a partially enlarged view of FIG. 18. FIG. 20 is a plan view showing the coil device A2. FIG. 21 is a cross-sectional end view taken along line XXI-XXI in FIG. 20. FIG. 22 is a bottom view showing the coil device A2. FIG. 23 is a view in which a portion (a portion of a first cylindrical portion 5A described below) is omitted from the perspective view shown in FIG. 18. In FIG. 23, a connecting portion 33 (described below) is omitted. FIG. 24 is a schematic view of the winding 3 when viewed along the circumferential direction t.

[0072] The coil component A2 has the winding 3 wound twice. The coil component A2 includes a first cylindrical portion 5A and a second cylindrical portion 5B due to the double winding of the winding 3. Similar to the first embodiment, the first cylindrical portion 5A and the second cylindrical portion 5B each have a toroidal shape. As shown in FIG. 23 , the second cylindrical portion 5B is located inside the first cylindrical portion 5A. The first cylindrical portion 5A forms the exterior of the coil component A1. The first cylindrical portion 5A and the second cylindrical portion 5B each have a planar shape, for example, a circular ring shape, and share a common central axis. That is, the central axis of the first cylindrical portion 5A in a planar view and the central axis of the second cylindrical portion 5B in a planar view are substantially the same. The direction in which this central axis extends corresponds to the axial direction s. Furthermore, the first cylindrical portion 5A and the second cylindrical portion 5B each have a cross-sectional shape, for example, a rectangular ring shape.

[0073] The winding 3 generates a magnetic field when an external input current is applied. The winding 3 is configured similarly to the primary winding 1 according to the first embodiment. As shown in FIGS. 18 to 24, the winding 3 includes a plurality of first winding portions 31, a plurality of second winding portions 32, and a connecting portion 33.

[0074] As shown in Fig. 24, each of the multiple first winding parts 31 has, for example, a rectangular ring shape when viewed in the circumferential direction t. As shown in Figs. 18 to 20, 22 and 23, the multiple first winding parts 31 are lined up in the circumferential direction t when viewed in the axial direction s. As shown in Fig. 24, each of the multiple first winding parts 31 includes a first upper conductor part 311, a first lower conductor part 312 and a pair of first connecting conductor parts 313, 314.

[0075] In each first winding portion 31, the first upper conductor portion 311 and the first lower conductor portion 312 are spaced apart in the axial direction s, as shown in FIG. 24 . As shown in FIGS. 20 and 22 , the first upper conductor portion 311 and the first lower conductor portion 312 each extend from the inner peripheral edge 51A of the first cylindrical portion 5A toward the outer peripheral edge 52A of the first cylindrical portion 5A when viewed in the axial direction s. The first upper conductor portion 311 and the first lower conductor portion 312 each have a strip shape when viewed in the axial direction s. As shown in FIG. 24 , the pair of first connecting conductor portions 313, 314 each extend from the first upper conductor portion 311 along the axial direction s. The first connecting conductor portion 313 is connected to the first lower conductor portion 312 of the same first winding portion 31. The first connecting conductor portion 314 is connected to the first lower conductor portion 312 of the first winding portion 31 adjacent to it in the circumferential direction t. The pair of first connecting conductors 313, 314 are each approximately perpendicular to the first upper conductor 311 and the first lower conductor 312. The first connecting conductor 313 overlaps the inner peripheral edge 51A of the first tubular portion 5A when viewed in the axial direction s, and the first connecting conductor 314 overlaps the outer peripheral edge 52A of the first tubular portion 5A when viewed in the axial direction s. When viewed along the radial direction u, the pair of first connecting conductors 313, 314 each have a band shape extending in the axial direction s.

[0076] In this embodiment, each first upper conductor 311 is inclined in one direction in the circumferential direction t with respect to the radial direction u, and each first lower conductor 312 is inclined in the other direction in the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 20 , the radial direction u overlapping each first connecting conductor 313 is defined as the radial direction u3, and the first upper conductor 311 connected to the first connecting conductor 313 is inclined clockwise in the circumferential direction t with respect to the radial direction u3. Furthermore, the first lower conductor 312 connected to the first connecting conductor 313 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u3. In this way, the first upper conductor 311 and the first lower conductor 312 are inclined in opposite directions in the circumferential direction t with respect to the radial direction u, thereby forming a pair of first connecting conductors 313, 314 along the axial direction s.

[0077] In this embodiment, two first upper conductors 311 adjacent to each other in the circumferential direction t and two first lower conductors 312 adjacent to each other in the circumferential direction t are disposed at a predetermined interval. The interval is, for example, substantially the same on the inner peripheral edge 51A side and the outer peripheral edge 52A side. With this configuration, the dimension of the first connecting conductor 314 along the circumferential direction t is greater than the dimension of the first connecting conductor 313 along the circumferential direction t when viewed in the axial direction s.

[0078] Among the multiple first winding parts 31, two adjacent first winding parts 31 in the circumferential direction t are directly connected to each other, and the input current flowing through the winding 3 flows sequentially through the multiple first winding parts 31. At this time, the input current is transmitted to the first connecting conductor 314 of each first winding part 31 from the first lower conductor 312 of the first winding part 31 adjacent to it on one side in the circumferential direction t. This input current then flows from the first connecting conductor 314 to the first lower conductor 312 via the first upper conductor 311 and the first connecting conductor 313. That is, in the example shown in FIG. 24 , the input current flowing through each first winding part 31 flows counterclockwise. Then, it is transmitted to the first winding part 31 adjacent to it on the other side in the circumferential direction t. In this way, the input current of the winding 3 makes a circuit through each of the multiple first winding parts 31. Note that the direction of the input current flowing through the first winding part 31 may be opposite to that in the above example. That is, the first lower conductor portion 312 of each first winding portion 31 receives the input current from the first connecting conductor portion 314 of the first winding portion 31 adjacent to it on the other side in the circumferential direction t. This input current flows from the first lower conductor portion 312 to the first connecting conductor portion 314 via the first connecting conductor portion 313 and the first upper conductor portion 311. That is, in the example shown in FIG. 24 , the input current flowing in each first winding portion 31 may flow clockwise.

[0079] As shown in FIG. 24 , each of the multiple second winding portions 32 has a shape, for example, a rectangular ring shape when viewed in the circumferential direction t. As shown in FIG. 24 , each second winding portion 32 is located inward of each first winding portion 31 when viewed in the circumferential direction t. As shown in FIG. 20 and FIG. 22 , the multiple second winding portions 32 are aligned in the circumferential direction t when viewed in the axial direction s. As shown in FIG. 20 and FIG. 22 , the multiple first winding portions 31 and the multiple second winding portions 32 are alternately arranged in the circumferential direction t when viewed in the axial direction s. As shown in FIG. 24 , each of the multiple second winding portions 32 includes a second upper conductor portion 321, a second lower conductor portion 322, and a pair of second connection conductor portions 323, 324.

[0080] In each second winding portion 32, the second upper conductor 321 and the second lower conductor 322 are spaced apart in the axial direction s, as shown in FIG. 24 . As shown in FIGS. 20 and 22 , the second upper conductor 321 and the second lower conductor 322 each extend from the inner circumferential edge 51B of the second cylindrical portion 5B toward the outer circumferential edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. The second upper conductor 321 and the second lower conductor 322 each have a strip shape when viewed in the axial direction s. As shown in FIG. 24 , the pair of second connecting conductors 323 and 324 each extend from the second upper conductor 321 along the axial direction s. The second connecting conductor 323 is connected to the second lower conductor 322 of the same second winding portion 32. The second connecting conductor 324 is connected to the second lower conductor 322 of the second winding portion 32 adjacent to it in the circumferential direction t. The pair of second connection conductors 323, 324 are each approximately perpendicular to the second upper conductor 321 and the second lower conductor 322. The second connection conductor 323 overlaps the inner peripheral edge 51B of the second tubular portion 5B when viewed in the axial direction s, and the second connection conductor 324 overlaps the outer peripheral edge 52B of the second tubular portion 5B when viewed in the axial direction s. When viewed along the radial direction u, the pair of second connection conductors 323, 324 each have a band shape extending in the axial direction s.

[0081] In this embodiment, each second upper conductor 321 is inclined to one side of the circumferential direction t with respect to the radial direction u, and each second lower conductor 322 is inclined to the other side of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 20 , the radial direction u overlapping each second connection conductor 323 is defined as the radial direction u3, and the second upper conductor 321 connected to the second connection conductor 323 is inclined clockwise in the circumferential direction t with respect to the radial direction u3. Furthermore, the second lower conductor 322 connected to the second connection conductor 323 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u3. In this way, the second upper conductor 321 and the second lower conductor 322 are inclined to the opposite side of the circumferential direction t with respect to the radial direction u, so that each pair of second connection conductors 323, 324 can be formed along the axial direction s.

[0082] In this embodiment, two second upper conductors 321 adjacent to each other in the circumferential direction t and two second lower conductors 322 adjacent to each other in the circumferential direction t are disposed at a predetermined interval. The interval is, for example, substantially the same on the inner peripheral edge 51B side and the outer peripheral edge 52B side. With this configuration, the dimension of the second connecting conductor 324 along the circumferential direction t is greater than the dimension of the second connecting conductor 323 along the circumferential direction t when viewed in the axial direction s.

[0083] Among the multiple second winding parts 32, two adjacent second winding parts 32 in the circumferential direction t are directly connected to each other, and the input current flowing through the winding 3 flows sequentially through the multiple second winding parts 32. At this time, the input current is transmitted to the second connecting conductor 324 of each second winding part 32 from the second lower conductor 322 of the second winding part 32 adjacent to it on one side in the circumferential direction t. This input current then flows from the second connecting conductor 324 to the second lower conductor 322 via the second upper conductor 321 and the second connecting conductor 323. That is, in the example shown in FIG. 24 , the input current flowing through each second winding part 32 flows counterclockwise. Therefore, the direction of the input current flowing through each first winding part 31 and the direction of the input current flowing through each second winding part 32 are the same when viewed along the circumferential direction t. In this way, the input current to the winding 3 circulates through each of the multiple second winding parts 32. The direction of the input current flowing through the second winding part 32 may be opposite to that in the above example. That is, the second lower conductor part 322 of each second winding part 32 receives the input current from the second connecting conductor part 324 of the second winding part 32 adjacent to it on the other side in the circumferential direction t. This input current then flows from the second lower conductor part 322 to the second connecting conductor part 324 via the second connecting conductor part 323 and the second upper conductor part 321. That is, in the example shown in FIG. 24 , the input current flowing through each second winding part 32 may be configured to flow clockwise. However, the direction of the input current flowing through each first winding part 31 and the direction of the input current flowing through each second winding part 32 are the same when viewed along the circumferential direction t.

[0084] 19, the connection portion 33 connects one of the plurality of first winding portions 31 and one of the plurality of second winding portions 32. For example, the connection portion 33 is connected to a first lower conductor portion 312 of one of the plurality of first winding portions 31 and a second upper conductor portion 321 of one of the plurality of second winding portions 32, thereby establishing electrical continuity between them.

[0085] The winding 3 has a plurality of first winding portions 31 connected in series along the circumferential direction t, and a plurality of second winding portions 32 connected in series along the circumferential direction t. These are connected by connecting portions 33. Therefore, the input current of the winding 3 makes a circuit through the plurality of first winding portions 31, and then is input to the plurality of second winding portions 32 via the connecting portions 33, and makes a circuit through the plurality of second winding portions 32.

[0086] In the coil device A2, a plurality of first winding portions 31 are arranged in the circumferential direction t to form a first cylindrical portion 5A. A plurality of second winding portions 32 are arranged in the circumferential direction t to form a second cylindrical portion 5B. The second cylindrical portion 5B is located inside the first cylindrical portion 5A.

[0087] 18 to 24, in the coil device A2, the first winding portions 31 and the second winding portions 32 partially overlap when viewed in the axial direction s and also partially overlap when viewed in the radial direction u. That is, when viewed in the axial direction s, the first upper conductor portions 311 and the second upper conductor portions 321 overlap with each other, and the first lower conductor portions 312 and the second lower conductor portions 322 overlap with each other. When viewed in the radial direction u, the first connecting conductor portions 313 and the second connecting conductor portions 323 overlap with each other, and the first connecting conductor portions 314 and the second connecting conductor portions 324 overlap with each other.

[0088] Next, the coil-built-in substrate B2 incorporating the coil component A2 will be described with reference to Fig. 25 to Fig. 27. Fig. 25 is a perspective view showing the coil-built-in substrate B2. Fig. 26 is a plan view showing the coil-built-in substrate B2. Fig. 27 is a cross-sectional view taken along line XXVII-XXVII in Fig. 26.

[0089] The coil-built-in substrate B2 is a printed circuit board, similar to the coil-built-in substrate B1. The coil-built-in substrate B2 is also not limited to a printed circuit board and may be a semiconductor substrate or a ceramic substrate. The coil-built-in substrate B2 incorporates the coil component A2. The coil-built-in substrate B2 is, for example, rectangular in plan view. The coil-built-in substrate B2 includes multiple wiring layers 7, multiple through electrodes 79, an insulating member 8, and a pair of terminals 9C.

[0090] In the coil-built-in substrate B2, the multiple wiring layers 7 also include a first wiring layer 71, a second wiring layer 72, a third wiring layer 73, and a fourth wiring layer 74, each having a wiring pattern formed thereon, as shown in FIG.

[0091] 27, the wiring pattern in the first wiring layer 71 forms a plurality of first upper conductors 311. The wiring pattern in the second wiring layer 72 forms a plurality of second upper conductors 321. The wiring pattern in the third wiring layer 73 forms a plurality of second lower conductors 322. The wiring pattern in the fourth wiring layer 74 forms a plurality of first lower conductors 312.

[0092] 27 , in the present embodiment as well, the separation distance in the axial direction s between the first wiring layer 71 and the second wiring layer 72 is substantially the same as the separation distance in the axial direction s between the third wiring layer 73 and the fourth wiring layer 74. The separation distance in the axial direction s between the second wiring layer 72 and the third wiring layer 73 is greater than the separation distance in the axial direction s between the first wiring layer 71 and the second wiring layer 72 and the separation distance in the axial direction s between the third wiring layer 73 and the fourth wiring layer 74. As a result, in the winding 3 of the coil component A2, the separation distance in the axial direction s between the first upper conductor 311 and the second upper conductor 321 is substantially the same as the separation distance in the axial direction s between the second lower conductor 322 and the first lower conductor 312. Furthermore, the separation distance in the axial direction s between the second upper conductor portion 321 and the second lower conductor portion 322 is greater than the separation distance in the axial direction s between the first upper conductor portion 311 and the second upper conductor portion 321, and the separation distance in the axial direction s between the second lower conductor portion 322 and the first lower conductor portion 312.

[0093] Furthermore, a pair of first connection conductors 313, 314 (first winding portion 31) are formed by through electrodes 79 that connect the first wiring layer 71 and the fourth wiring layer 74 to each other. Furthermore, a pair of second connection conductors 323, 324 (second winding portion 32) are formed by through electrodes 79 that connect the second wiring layer 72 and the third wiring layer 73 to each other.

[0094] In the coil-built-in substrate B2, the wiring patterns of the plurality of wiring layers 7 (first wiring layer 71, second wiring layer 72, third wiring layer 73, fourth wiring layer 74) and the plurality of through electrodes 79 form the coil component A2.

[0095] The pair of terminals 9C are electrically connected to the winding 3 and are input terminals for inputting an input current to the winding 3. Each of the pair of terminals 9C includes a portion formed outside the insulating member 8 and a terminal wiring portion 90C connected to this portion and the winding 3. As shown in FIG. 25 , the terminal wiring portion 90C of one terminal 9C is connected to, for example, the first upper conductor portion 311 (first winding portion 31). The terminal wiring portion 90C of the other terminal 9C is connected to, for example, the second lower conductor portion 322 (second winding portion 32). When a voltage is applied between the pair of terminals 9C, an input current flows from one terminal 9C to the other terminal 9C via the winding 3. This generates a magnetic field from the winding 3.

[0096] 25, the pair of terminals 9C are each formed so as to be exposed from the upper surface (surface facing one side in the axial direction s) of the insulating member 8, but this is not limiting. Whether the pair of terminals 9C are each exposed from the upper surface of the insulating member 8 or from the lower surface (surface facing the other side in the axial direction s) of the insulating member 8 can be changed as appropriate depending on the specifications of the coil-built-in substrate B2.

[0097] The coil component A2 and the coil-built-in substrate B2 according to the second embodiment have the following advantages.

[0098] The coil component A2 has a winding 3 through which an input current flows from the outside. The winding 3 includes a plurality of first winding portions 31, each of which is annular when viewed in a first direction (circumferential direction t). With this configuration, in each first winding portion 31, for example, the input current flows in opposite directions in portions facing each other in the axial direction s. Therefore, the magnetic fluxes generated by these portions face in opposite directions outside each first winding portion 31 and cancel each other out. The plurality of first winding portions 31 form a first cylindrical portion 5A that forms the exterior of the coil component A2. Therefore, in the coil component A2, the magnetic flux outside each first winding portion 31 (first cylindrical portion 5A) is reduced, thereby suppressing magnetic flux leakage to the outside.

[0099] In the coil component A2, the winding 3 includes a plurality of first winding portions 31 and a plurality of second winding portions 32. The direction of the input current flowing through each of the plurality of first winding portions 31 and the direction of the input current flowing through each of the plurality of second winding portions 32 are the same when viewed in the first direction (circumferential direction t). With this configuration, the magnetic flux generated by the input current flowing through each of the first winding portions 31 and the magnetic flux generated by the input current flowing through each of the second winding portions 32 are oriented in the same direction inside the plurality of second winding portions 32, i.e., inside the second cylindrical portion 5B, and the two magnetic fluxes reinforce each other. Therefore, the inductance value of the coil component A2 can be improved because the magnetic flux inside the second cylindrical portion 5B is increased.

[0100] Coil component A1 does not have a magnetic core for the winding 3 and is an air-core type. In coil components with a magnetic core, the magnetic core can cause energy loss when the input current to the winding 3 is in the high frequency band. Therefore, coil component A2 does not have a magnetic core, so energy loss due to the magnetic core can be suppressed even when the input current to the winding 3 is in the high frequency band.

[0101] In the coil-built-in substrate B2, wiring patterns are formed on each of the first wiring layer 71, the second wiring layer 72, the third wiring layer 73, and the fourth wiring layer 74, and the coil component A2 is formed by these wiring patterns. With this configuration, the coil component A2 is formed, for example, by a manufacturing process for a printed circuit board (or a semiconductor substrate or a ceramic substrate). Therefore, the coil-built-in substrate B2 facilitates the manufacturing of the coil component A2, which has a complex wiring structure. Furthermore, because the coil component A2 is formed by wiring patterns on multiple wiring layers 7, the height of the coil component A2 can be reduced.

[0102] In the second embodiment, an example has been shown in which the first winding portions 31 and the second winding portions 32 overlap when viewed in the axial direction s, but this is not limiting. For example, the first winding portions 31 and the second winding portions 32 may or may not partially overlap when viewed in the axial direction s. However, the coil component A2 is more preferable than the coil component according to this modified example in terms of improving the inductance value.

[0103] In the second embodiment, an example has been described in which, in each first winding portion 31, the first upper conductor portion 311 is inclined to one side of the circumferential direction t with respect to the radial direction u, and the first lower conductor portion 312 is inclined to the other side of the circumferential direction t with respect to the radial direction u. However, this is not limiting. In each first winding portion 31, the first upper conductor portion 311 does not have to be inclined to one side of the circumferential direction t. In this case, the pair of first connecting conductor portions 313, 314 are shaped to extend along the axial direction s, so the inclination angle of the first lower conductor portion 312 in the circumferential direction t with respect to the radial direction u is large. Conversely, the first lower conductor portion 312 does not have to be inclined to the other side of the circumferential direction t. In this case, the pair of first connecting conductor portions 313, 314 are shaped to extend along the axial direction s, so the inclination angle of the first upper conductor portion 311 in the circumferential direction t with respect to the radial direction u is large. Furthermore, the first upper conductor 311 and the first lower conductor 312 do not have to be inclined in the circumferential direction t. In this case, the pair of first connecting conductors 313, 314 are inclined with respect to the axial direction s. This type of modification also applies to the second upper conductor 321 and the second lower conductor 322 in each second winding part 32.

[0104] In the second embodiment, in each first winding portion 31, the dimension of the first connecting conductor 314 along the circumferential direction t is larger than the dimension of the first connecting conductor 313 along the circumferential direction t when viewed in the axial direction s. However, this is not limiting. These dimensions may be approximately the same. In this case, the predetermined gaps provided between two first upper conductors 311 adjacent to each other in the circumferential direction t and between two first lower conductors 312 adjacent to each other in the circumferential direction t are relatively larger on the side closer to the outer peripheral edge 52A and relatively smaller on the side closer to the inner peripheral edge 51A in the radial direction u. This modification also applies to the pair of second connecting conductors 323, 324 in each second winding portion 32.

[0105] In the first and second embodiments, examples have been shown in which the plurality of through electrodes 79 in each of the coil-built-in substrates B1 and B2 are each configured in a columnar shape, but this is not limiting. For example, each through electrode 79 may be configured as a so-called through via. The through via has, for example, a circular shape in a plan view. Furthermore, a plurality of through vias may be provided for each through electrode 79.

[0106] In the first and second embodiments, the coil components A1 and A2 have a toroidal shape in appearance, but this is not limiting. For example, each coil component A1 may have a solenoid shape. In this disclosure, a solenoid shape refers to a shape whose planar shape is not annular like a toroidal shape, and includes not only linear windings but also curved windings. In this modification, the multiple first winding portions 11 and multiple second winding portions 12 of the primary winding 1 and the multiple first winding portions 21 and multiple second winding portions 22 of the secondary winding 2, or the multiple first winding portions 31 and second winding portions 32 of the winding 3, are arranged linearly or curvedly. However, in the case of a solenoid shape, since the planar shape is not annular, a toroidal configuration like each of the coil components A1 and A2 is more effective in suppressing magnetic flux leakage.

[0107] In the first and second embodiments, examples have been shown in which the coil components A1 and A2 are configured by wiring patterns in multiple wiring layers 7 of the coil-built-in substrate B1, but the present invention is not limited to this. For example, the primary winding 1 and the secondary winding 2 (or winding 3) may be formed by winding a wire-shaped or plate-shaped lead wire.

[0108] The coil component and the coil-embedded substrate according to the present disclosure are not limited to the above-described embodiments. The specific configurations of the coil component and the coil-embedded substrate according to the present disclosure can be freely modified in various ways. The present disclosure includes the embodiments described in the following appendices. Appendix 1. a primary winding that generates a magnetic field using an external input current; a secondary winding through which an induced current generated by the magnetic field flows; It is equipped with the primary winding includes a plurality of primary-side first winding portions and a plurality of primary-side second winding portions each having an annular shape when viewed in a first direction; the secondary winding includes a plurality of secondary first winding portions and a plurality of secondary second winding portions each having an annular shape when viewed in the first direction, the plurality of primary-side first winding portions and the plurality of secondary-side first winding portions are alternately arranged in the first direction to form a first cylindrical portion; the plurality of primary-side second winding portions and the plurality of secondary-side second winding portions are alternately arranged in the first direction to form a second cylindrical portion, the second cylindrical portion is located inside the first cylindrical portion when viewed in the first direction, A coil component in which the direction of the input current flowing through each of the plurality of primary side first winding portions and the direction of the input current flowing through each of the plurality of primary side second winding portions are the same. Appendix 2. each of the plurality of primary side first winding portions includes a primary side first upper conductor portion and a primary side first lower conductor portion spaced apart in a thickness direction perpendicular to the first direction; each of the plurality of primary side second winding portions includes a primary side second upper conductor portion and a primary side second lower conductor portion spaced apart in the thickness direction; each of the plurality of secondary side first winding portions includes a secondary side first upper conductor portion and a secondary side first lower conductor portion spaced apart in the thickness direction; 2. The coil component of claim 1, wherein each of the plurality of secondary side second winding portions includes a secondary side second upper conductor portion and a secondary side second lower conductor portion spaced apart in the thickness direction. Appendix 3. the primary-side first upper conductor portion and the secondary-side first upper conductor portion overlap each other when viewed in the first direction, 3. The coil component according to claim 2, wherein the primary-side first lower conductor portion and the secondary-side first lower conductor portion overlap when viewed in the first direction. Appendix 4. the primary-side second upper conductor portion and the secondary-side second upper conductor portion overlap each other when viewed in the first direction, 4. The coil component according to claim 3, wherein the primary-side second lower conductor portion and the secondary-side second lower conductor portion overlap when viewed in the first direction. Appendix 5. A coil component as described in Appendix 4, wherein in the thickness direction, the distance between the primary side second upper conductor portion and the primary side second lower conductor portion is greater than the distance between the primary side first upper conductor portion and the primary side second upper conductor portion and the distance between the primary side second lower conductor portion and the primary side first lower conductor portion. Appendix 6. the primary-side first upper conductor portion and the secondary-side second upper conductor portion overlap each other when viewed in the thickness direction, 6. The coil component according to claim 3, wherein the primary-side first lower conductor portion and the secondary-side second lower conductor portion overlap each other when viewed in the thickness direction. Appendix 7. the primary-side second upper conductor portion and the secondary-side first upper conductor portion overlap each other when viewed in the thickness direction, 7. The coil component according to claim 6, wherein the primary-side second lower conductor portion and the secondary-side first lower conductor portion overlap each other when viewed in the thickness direction. Appendix 8. each of the plurality of primary side first winding portions includes a pair of primary side first connecting conductor portions extending in the thickness direction from the primary side first upper conductor portion; one of the pair of primary-side first connecting conductor portions is connected to the primary-side first lower conductor portion; each of the plurality of primary side second winding portions includes a pair of primary side second connecting conductor portions extending in the thickness direction from the primary side second upper conductor portion; 8. The coil component according to claim 3, wherein one of the pair of primary side second connection conductors is connected to the primary side second lower conductor. Appendix 9. the other of the pair of primary-side first connecting conductor portions is connected to the primary-side first lower conductor portion of the adjacent primary-side first winding portion, 9. The coil component according to claim 8, wherein the other of the pair of primary side second connecting conductor portions is connected to the primary side second lower conductor portion of the adjacent primary side second winding portion. Appendix 10. 10. The coil component of claim 9, wherein the primary winding further includes a primary connection portion that electrically connects one of the plurality of primary first winding portions and one of the plurality of primary second winding portions. Appendix 11. each of the plurality of secondary-side first winding portions includes a pair of secondary-side first connecting conductor portions extending in the thickness direction from the secondary-side first upper conductor portion; one of the pair of secondary-side first connecting conductor portions is connected to the secondary-side first lower conductor portion, each of the plurality of secondary-side second winding portions includes a pair of secondary-side second connecting conductor portions extending from the secondary-side second upper conductor portion in the thickness direction; The coil component according to claim 9 or 10, wherein one of the pair of secondary-side second connecting conductors is connected to the secondary-side second lower conductor. Appendix 12. the other of the pair of secondary-side first connecting conductor portions is connected to the secondary-side first lower conductor portion of the adjacent secondary-side first winding portion, 12. The coil component according to claim 11, wherein the other of the pair of secondary side second connecting conductor portions is connected to the secondary side second lower conductor portion of the adjacent secondary side second winding portion. Appendix 13. 13. The coil component of claim 12, wherein the secondary winding further includes a secondary connection portion that electrically connects one of the plurality of secondary first winding portions to one of the plurality of secondary second winding portions. Appendix 14. The coil component according to any one of Supplementary Note 2 to Supplementary Note 13, wherein the first cylindrical portion and the second cylindrical portion are each annular in shape with the first direction as a circumferential direction when viewed in the thickness direction. Appendix 15. A coil component as described in Appendix 14, wherein the primary side first upper conductor portion, the primary side first lower conductor portion, the secondary side first upper conductor portion, and the secondary side first lower conductor portion each extend from the inner peripheral side to the outer peripheral side of the first cylindrical portion when viewed in the thickness direction. Appendix 16. A coil component as described in Appendix 15, wherein the primary side first upper conductor portion, the primary side first lower conductor portion, the secondary side first upper conductor portion, and the secondary side first lower conductor portion are each strip-shaped when viewed in the thickness direction. Appendix 17. the primary side first upper conductor portion and the secondary side first upper conductor portion are each inclined toward one side in the circumferential direction of the first cylindrical portion with respect to the radial direction of the first cylindrical portion when viewed in the thickness direction, A coil component as described in Appendix 15 or Appendix 16, wherein the primary side first lower conductor portion and the secondary side first lower conductor portion are each inclined toward the other circumferential direction of the first cylindrical portion with respect to the radial direction of the first cylindrical portion when viewed in the thickness direction. Appendix 18. A coil component described in any one of Appendix 14 to Appendix 17, wherein the primary side second upper conductor portion, the primary side second lower conductor portion, the secondary side second upper conductor portion, and the secondary side second lower conductor portion each extend from the inner peripheral edge to the outer peripheral edge of the second cylindrical portion when viewed in the thickness direction. Appendix 19. A coil component as described in Appendix 18, wherein the primary side second upper conductor portion, the primary side second lower conductor portion, the secondary side second upper conductor portion, and the secondary side second lower conductor portion are each strip-shaped when viewed in the thickness direction. Appendix 20. the primary-side second upper conductor portion and the secondary-side second upper conductor portion are each inclined toward one side in the circumferential direction of the second cylindrical portion with respect to the radial direction of the second cylindrical portion when viewed in the thickness direction, A coil component described in either Appendix 18 or Appendix 19, wherein the primary side second lower conductor portion and the secondary side second lower conductor portion are each inclined toward the other circumferential direction of the second cylindrical portion with respect to the radial direction of the second cylindrical portion when viewed in the thickness direction. Appendix 21. It has a winding that generates a magnetic field using an external input current. the winding includes a plurality of first winding portions and a plurality of second winding portions each having an annular shape when viewed in a first direction; the plurality of first winding portions are arranged in the first direction and form a first cylindrical portion; the plurality of second winding portions are arranged in the first direction and form a second cylindrical portion; the second cylindrical portion is located inside the first cylindrical portion when viewed in the first direction, the first cylindrical portion and the second cylindrical portion each have an annular shape when viewed in a thickness direction perpendicular to the first direction, a direction of the input current flowing through each of the plurality of first winding portions and a direction of the input current flowing through each of the plurality of second winding portions are the same; Appendix 22. A coil-embedded substrate incorporating the coil component according to any one of Supplementary Note 2 to Supplementary Note 21, a plurality of wiring layers stacked in the thickness direction; a plurality of insulating layers interposed between the plurality of wiring layers in the thickness direction; It is equipped with The coil component is configured by wiring patterns in the plurality of wiring layers. Appendix 23. 23. The coil-embedded substrate according to claim 22, wherein the coil component is a transformer. [Explanation of symbols]

[0109] A1, A2: Coil component 1: Primary winding 11: First winding portion 111: First upper conductor portion 112: First lower conductor portion 113, 114: First connecting conductor portion 12: Second winding portion 121: Second upper conductor portion 122: Second lower conductor portion 123, 124: Second connecting conductor portion 13: Connection 2: Secondary winding 21: First winding portion 211: First upper conductor portion 212: First lower conductor portion 213, 214: First connecting conductor portion 22: Second winding portion 221: Second upper conductor portion 222: Second lower conductor portion 223, 224: Second connecting conductor portion 23: Connection 3: Winding 31: First winding portion 311: First upper conductor portion 312: First lower conductor portion 313, 314: First connecting conductor portion 32: Second winding section 321: Second upper conductor section 322: Second lower conductor portion 323, 324: Second connecting conductor portion 33: Connection portion 5A: First cylindrical portion 5B: Second cylindrical portion 51A, 51B: Inner peripheral edge 52A, 52B: Outer rim B1, B2: Coil built-in board 7: Wiring layer 71: First wiring layer 72: 2nd wiring layer 73: 3rd wiring layer 74: 4th wiring layer 79: Through electrode 8: Insulating member 81: Insulating layer 9A, 9B, 9C: Terminal 90A, 90B, 90C: Terminal wiring section s: Axial direction t: Circumferential direction u: Radial direction

Claims

1. It has a winding that generates a magnetic field using an external input current. the winding includes a plurality of first winding portions and a plurality of second winding portions each having a rectangular annular shape when viewed in a first direction; the plurality of first winding portions are arranged in the first direction and form a first cylindrical portion; the plurality of second winding portions are arranged in the first direction and form a second cylindrical portion; the second cylindrical portion is located inside the first cylindrical portion as viewed in the first direction, the first cylindrical portion and the second cylindrical portion each have an annular shape when viewed in a thickness direction perpendicular to the first direction, a direction of the input current flowing through each of the plurality of first winding portions and a direction of the input current flowing through each of the plurality of second winding portions are the same;

2. The coil component according to claim 1 , wherein each of the plurality of first winding portions includes a first upper conductor portion and a first lower conductor portion spaced apart in the thickness direction.

3. The coil component according to claim 2 , wherein in each of the plurality of first winding portions, the first upper conductor portion and the first lower conductor portion are each strip-shaped when viewed in the thickness direction.

4. 4. The coil component according to claim 2, wherein in each of the plurality of first winding portions, the first upper conductor portion is inclined in one direction of the first direction relative to the radial direction of the first cylindrical portion when viewed in the thickness direction, and the first lower conductor portion is inclined in the other direction of the first direction relative to the radial direction of the first cylindrical portion when viewed in the thickness direction.

5. each of the plurality of first winding portions includes a pair of first connection conductor portions each extending from the first upper conductor portion in the thickness direction; 5. The coil component according to claim 2, wherein in each of the plurality of first winding portions, one of the pair of first connection conductor portions is connected to the first lower conductor portion.

6. The coil component according to claim 5 , wherein in each of the plurality of first winding portions, each of the pair of first connection conductor portions has a strip shape when viewed in a radial direction of the first cylindrical portion.

7. 7. The coil component according to claim 5, wherein in each of the plurality of first winding portions, one of the pair of first connecting conductor portions overlaps the outer peripheral edge of the first cylindrical portion when viewed in the thickness direction, and the other of the pair of first connecting conductor portions overlaps the inner peripheral edge of the first cylindrical portion when viewed in the thickness direction.

8. The coil component according to claim 1 , wherein each of the plurality of second winding portions includes a second upper conductor portion and a second lower conductor portion spaced apart in the thickness direction.

9. The coil component according to claim 8 , wherein in each of the plurality of second winding portions, the second upper conductor portion and the second lower conductor portion are each strip-shaped when viewed in the thickness direction.

10. 10. A coil component as described in claim 8 or claim 9, wherein in each of the plurality of second winding portions, the second upper conductor portion is inclined in one side of the first direction with respect to the radial direction of the second cylindrical portion when viewed in the thickness direction, and the second lower conductor portion is inclined in the other side of the first direction with respect to the radial direction of the second cylindrical portion when viewed in the thickness direction.

11. each of the plurality of second winding portions includes a pair of second connection conductor portions extending in the thickness direction from the second upper conductor portion; 11. The coil component according to claim 8, wherein in each of the plurality of second winding portions, one of the pair of second connection conductor portions is connected to the second lower conductor portion.

12. The coil component according to claim 11 , wherein in each of the plurality of second winding portions, each of the pair of second connection conductor portions has a strip shape when viewed in a radial direction of the second cylindrical portion.

13. 13. The coil component according to claim 11 or 12, wherein in each of the plurality of second winding portions, one of the pair of second connecting conductor portions overlaps the outer peripheral edge of the second cylindrical portion when viewed in the thickness direction, and the other of the pair of second connecting conductor portions overlaps the inner peripheral edge of the second cylindrical portion when viewed in the thickness direction.

14. A coil-embedded substrate incorporating the coil component according to any one of claims 1 to 13, a plurality of wiring layers stacked in the thickness direction; a plurality of insulating layers interposed between the plurality of wiring layers in the thickness direction; It is equipped with The coil component is configured by wiring patterns in the plurality of wiring layers.

15. The coil-embedded substrate according to claim 14 , wherein the coil component is a transformer in which the winding functions as a primary winding.

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