Coil component and substrate with built-in coil

Abstract

This coil component comprises a primary winding that generates a magnetic field using input current from the outside, and a secondary winding in which flows an induction current that is generated by the magnetic field. The primary winding includes a plurality of primary-side first circumference parts and a plurality of primary-side second circumference parts, each of which has an annular shape as seen from a first direction. The secondary winding includes a plurality of secondary-side first circumference parts and a plurality of secondary-side second circumference parts, each of which has an annular shape as seen from the first direction. The plurality of primary-side first circumference parts and the plurality of secondary-side first circumference parts are arranged alternating in the first direction and constitute a first tubular part. The plurality of primary-side second circumference parts and the plurality of secondary-side second circumference parts are arranged alternating in the first direction and constitute a second tubular part. The second tubular part is positioned inward of the first tubular part as seen from the first direction. The orientation of the input current flowing to each of the plurality of primary-side first circumference parts, and the orientation of the input current flowing to each of the plurality of primary-side second circumference parts, are the same.

Description

Technical Field

[0001] The present disclosure relates to coil components and substrates with built-in coils.

Background Art

[0002] Coil components such as inductors and transformers are mounted on 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

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, it is considered that the less magnetic flux leakage there is in inductors and transformers, the better. This is because such magnetic flux leakage causes the generation of radiation noise and heat generation.

[0005] The present disclosure has been conceived in view of the above circumstances, and one of its objects is to provide a coil component that suppresses magnetic flux leakage and a substrate with a built-in coil that includes the coil component.

Means for Solving the Problems

[0006] The coil component provided by the first aspect of the present disclosure includes a primary winding that generates a magnetic field by an input current from the outside, 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-turn portions and a plurality of primary-side second-turn portions, each of which is annular when viewed in the first direction. The secondary winding includes a plurality of secondary-side first-turn portions and a plurality of secondary-side second-turn portions, each of which is annular when viewed in the first direction. The plurality of primary-side first-turn portions and the plurality of secondary-side first-turn portions are alternately arranged in the first direction to form a first cylindrical portion. The plurality of primary-side second-turn portions and the plurality of secondary-side second-turn 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-turn portions and the direction of the input current flowing through each of the plurality of primary-side second-turn portions face the same direction.

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

[0008] The coil-embedded substrate provided by the 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 laminated 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.

Advantages of the Invention

[0009] According to the coil component and the substrate with a built-in coil of the present disclosure, magnetic flux leakage can be suppressed.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out 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, the same or similar components are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] Regarding the coil component A1 according to the first embodiment, with reference to FIGS. 1 to 14, an explanation will be given. 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 it is preferably in an air-core form 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 an annular shape that substantially makes one turn, for example, an annular shape, an elliptical annular shape, or a polygonal annular shape. Note that the planar shape of the coil component A1 does not necessarily have to make one turn. The cross-sectional shape of the coil component A1 is preferably an annular shape that substantially makes one turn, for example, an annular shape, an elliptical annular shape, or a polygonal annular shape. The overall shape of the coil component A1 is constituted by various combinations of the above planar shape and the above cross-sectional shape. In the first embodiment, the case where the planar shape is an annular shape and the cross-sectional shape is a rectangular annular shape will be described as an example. For the sake of convenience of explanation, in the plan view of the coil component A1, 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 A1. The circumferential direction t coincides with the toroidal direction of the coil component A1. Also, the above cross-sectional shape corresponds to the cross-section in the 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 a coil component A1. FIG. 2 is a partial enlarged view obtained by enlarging a part of FIG. 1. FIG. 3 is a plan view showing the coil component A1. FIG. 4 is an end view of a cut surface along line IV-IV of FIG. 3. FIG. 5 is a view obtained by cutting the perspective view shown in FIG. 1 along the cut surface (cross section along line IV-IV of FIG. 3). In FIG. 5, the cut portion is indicated by an imaginary line (two-dot chain line). FIG. 6 is a bottom view showing the coil component A1. FIG. 7 is a view obtained by omitting a part (a part of a first cylindrical portion 5A described later) in the perspective view shown in FIG. 1. FIG. 8 is a perspective view showing a primary winding 1 of the coil component A1. FIG. 9 is a plan view showing the primary winding 1 of the coil component A1. FIG. 10 is a schematic view when the primary winding 1 shown in FIGS. 8 and 9 is viewed along the circumferential direction t. FIG. 11 is a perspective view showing a secondary winding 2 of the coil component A1. FIG. 12 is a plan view showing the secondary winding 2 of the coil component A1. FIG. 13 is a schematic view when the secondary winding 2 shown in FIGS. 11 and 12 is viewed along the circumferential direction t. FIG. 14 is a schematic view showing a part of the primary winding 1 and the secondary winding 2, and shows a connection example of a connection portion 13 (described later) and a connection portion 23 (described later). In FIGS. 1 to 13, the connection portions 13 and 23 are omitted. FIG. 14(a) is a view seen from the outside in the radial direction u to the inside in the radial direction u, FIGS. 14(b) and 14(c) are views seen from both sides in the circumferential direction t, respectively, and FIGS. 14(d) and 14(e) are views seen from both sides in the axial direction s, respectively.

[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 due to the primary winding 1 and the secondary winding 2 being doubly wound respectively. 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 appearance of the coil component A1. The first cylindrical portion 5A and the second cylindrical portion 5B each have a planar shape that is, for example, an annular shape and share a common central axis. That is, the central axis in the plan view of the first cylindrical portion 5A and the central axis in the plan view of the second cylindrical portion 5B substantially coincide. The direction in which this central axis extends corresponds to the axial direction s. Also, the first cylindrical portion 5A and the second cylindrical portion 5B each have a cross-sectional shape that is, for example, a rectangular annular shape.

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

[0016] As shown in FIG. 10, each of the plurality of first winding portions 11 has a shape that is, for example, a rectangular annular shape when viewed along the circumferential direction t. As shown in FIG. 9, the plurality of first winding portions 11 are arranged in the circumferential direction t when viewed in the axial direction s. The plurality of first winding portions 11 are a part of the first cylindrical portion 5A. As shown in FIG. 10, each of the plurality of 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, 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, 114 corresponds to the "pair of primary-side first connecting conductor portions".

[0017] In each first circumferential 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 to 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 are each strip-shaped when viewed in the axial direction s. Each of the pair of first connection conductor portions 113, 114 extends along the axial direction s from the first upper conductor portion 111 as shown in FIG. 10. The first connection conductor portion 113 is connected to the first lower conductor portion 112 of the same first circumferential portion 11. The first connection conductor portion 114 is connected to the first lower conductor portion 112 of the first circumferential portion 11 adjacent in the circumferential direction t. Each of the pair of first connection conductor portions 113, 114 is substantially orthogonal to the first upper conductor portion 111 and the first lower conductor portion 112. The first connection conductor portion 113 overlaps the inner peripheral edge 51A of the first cylindrical portion 5A when viewed in the axial direction s, and the first connection conductor portion 114 overlaps the outer peripheral edge 52A of the first cylindrical portion 5A when viewed in the axial direction s. Each of the pair of first connection conductor portions 113, 114 is strip-shaped and extends in the axial direction s when viewed along the radial direction u.

[0018] In the present embodiment, each first upper conductor portion 111 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and each first lower conductor portion 112 is inclined in the other direction of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 9, taking the radial direction u overlapping the first connection conductor portion 113 as the radial direction u11, the first upper conductor portion 111 connected to the first connection conductor portion 113 is inclined clockwise in the circumferential direction t with respect to the radial direction u11. Also, the first lower conductor portion 112 connected to the first connection conductor portion 113 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u11. In this way, by the first upper conductor portion 111 and the first lower conductor portion 112 being inclined on opposite sides of the circumferential direction t with respect to the radial direction u, the pair of first connection conductor portions 113, 114 can be formed along the axial direction s respectively.

[0019] Also, in the present embodiment, two first upper conductor portions 111 adjacent to each other in the circumferential direction t and two first lower conductor portions 112 adjacent to each other in the circumferential direction t are each arranged with a predetermined interval therebetween. The interval is substantially the same on the inner peripheral edge 51A side and the outer peripheral edge 52A side of the first cylindrical portion 5A, for example. With this configuration, when viewed in the axial direction s, the dimension of the first connection conductor portion 114 along the circumferential direction t is larger than the dimension of the first connection conductor portion 113 along the circumferential direction t.

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

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

[0022] In each second circumferential portion 12, the second upper conductor portion 121 and the second lower conductor portion 122 are spaced apart in the axial direction s as shown in FIG. 10. As shown in FIG. 9, the second upper conductor portion 121 and the second lower conductor portion 122 each extend from the inner peripheral edge 51B of the second cylindrical portion 5B toward the outer peripheral edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. The second upper conductor portion 121 and the second lower conductor portion 122 are each strip-shaped when viewed in the axial direction s. Each of the pair of second connection conductor portions 123, 124 extends along the axial direction s from the second upper conductor portion 121 as shown in FIG. 10. The second connection conductor portion 123 is connected to the second lower conductor portion 122 of the same second circumferential portion 12. The second connection conductor portion 124 is connected to the second lower conductor portion 122 of the second circumferential portion 12 adjacent in the circumferential direction t. Each of the pair of second connection conductor portions 123, 124 is substantially orthogonal to the second upper conductor portion 121 and the second lower conductor portion 122. The second connection conductor portion 123 overlaps the inner peripheral edge 51B of the second cylindrical portion 5B when viewed in the axial direction s, and the second connection conductor portion 124 overlaps the outer peripheral edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. Each of the pair of second connection conductor portions 123, 124 is strip-shaped and extends in the axial direction s when viewed along the radial direction u.

[0023] In this embodiment, each second upper conductor portion 121 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and each second lower conductor portion 122 is inclined in the other direction of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 9, taking the radial direction u overlapping the second connection conductor portion 123 as the radial direction u12, the second upper conductor portion 121 connected to the second connection conductor portion 123 is inclined clockwise in the circumferential direction t with respect to the radial direction u12. Further, the second lower conductor portion 122 connected to the second connection conductor portion 123 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u12. In this way, by inclining the second upper conductor portion 121 and the second lower conductor portion 122 on the opposite sides of the circumferential direction t with respect to the radial direction u, a pair of second connection conductor portions 123, 124 can be formed along the axial direction s respectively.

[0024] Also, in this embodiment, two second upper conductor portions 121 adjacent to each other in the circumferential direction t and two second lower conductor portions 122 adjacent to each other in the circumferential direction t are arranged with a predetermined interval therebetween. The interval is substantially the same, for example, between the inner peripheral edge 51B side and the outer peripheral edge 52B side of the second cylindrical portion 5B. With this configuration, when viewed in the axial direction s, the dimension along the circumferential direction t of the second connection conductor portion 124 is larger than the dimension along the circumferential direction t of the second connection conductor portion 123.

[0025] The plurality of second turns 12 are such that two adjacent second turns 12 in the circumferential direction t are directly connected, and the input current flowing through the primary winding 1 flows through the plurality of second turns 12 in sequence. At this time, the second connection conductor portion 124 of each second turn 12 receives the input current from the second lower conductor portion 122 of the second turn 12 adjacent to one side in the circumferential direction t. Then, this input current flows from the second connection conductor portion 124 through the second upper conductor portion 121 and the second connection conductor portion 123 to the second lower conductor portion 122. That is, in the example shown in FIG. 10, the input current flowing through each second turn 12 flows counterclockwise. Therefore, the direction of the input current flowing through each first turn 11 and the direction of the input current flowing through each second turn 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 plurality of second turns 12. Note that the direction of the input current flowing through the second turn 12 may be opposite to the above example. That is, the second lower conductor portion 122 of each second turn 12 receives the input current from the second connection conductor portion 124 of the second turn 12 adjacent to the other side in the circumferential direction t. Then, this input current flows from the second lower conductor portion 122 through the second connection conductor portion 123 and the second upper conductor portion 121 to the second connection conductor portion 124. That is, in the example shown in FIG. 10, the input current flowing through each second turn 12 may be configured to flow clockwise. However, the direction of the input current flowing through each first turn 11 and the direction of the input current flowing through each second turn 12 are made the same when viewed along the circumferential direction t.

[0026] The connection portion 13 connects one of the plurality of first turns 11 and one of the plurality of second turns 12. For example, as shown in FIG. 14, the connection portion 13 is connected to and electrically connects a first lower conductor portion 112 of one of the plurality of first turns 11 and a second upper conductor portion 121 of one of the plurality of second turns 12.

[0027] The primary winding 1 has a plurality of first circumferential portions 11 connected continuously along the circumferential direction t, and a plurality of second circumferential portions 12 connected continuously along the circumferential direction t. And these are connected by the connection portion 13. Therefore, the input current of the primary winding 1 enters the plurality of second circumferential portions 12 via the connection portion 13 after circulating through the plurality of first circumferential portions 11 and circulates through the plurality of second circumferential portions 12.

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

[0029] As shown in FIG. 13, each of the plurality of first circumferential portions 21 has a shape, for example, a rectangular ring shape when viewed along the circumferential direction t. As shown in FIG. 12, the plurality of first circumferential portions 21 are arranged in the circumferential direction t when viewed in the axial direction s. The plurality of first circumferential portions 21 are part of the first cylindrical portion 5A. Each of the plurality of first circumferential portions 21 includes a first upper conductor portion 211, a first lower conductor portion 212, and a pair of first connection 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 connection conductor portions 213, 214 corresponds to the "pair of secondary-side first connection conductor portions".

[0030] In each first circumferential 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 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 211 and the first lower conductor portion 212 are each strip-shaped when viewed in the axial direction s. Each of the pair of first connection conductor portions 213, 214 extends along the axial direction s from the first upper conductor portion 211 as shown in FIG. 13. The first connection conductor portion 213 is connected to the first lower conductor portion 212 of the same first circumferential portion 21. The first connection conductor portion 214 is connected to the first lower conductor portion 212 of the first circumferential portion 21 adjacent in the circumferential direction t. Each of the pair of first connection conductor portions 213, 214 is substantially orthogonal to the first upper conductor portion 211 and the first lower conductor portion 212. The first connection conductor portion 213 overlaps the inner peripheral edge 51A of the first cylindrical portion 5A when viewed in the axial direction s, and the first connection conductor portion 214 overlaps the outer peripheral edge 52A of the first cylindrical portion 5A when viewed in the axial direction s. Each of the pair of first connection conductor portions 213, 214 is strip-shaped and extends in the axial direction s when viewed along the radial direction u.

[0031] In the present embodiment, each first upper conductor portion 211 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and each first lower conductor portion 212 is inclined in the other direction of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 12, taking the radial direction u overlapping the first connection conductor portion 213 as the radial direction u21, the first upper conductor portion 211 connected to the first connection conductor portion 213 is inclined clockwise in the circumferential direction t with respect to the radial direction u21. Further, the first lower conductor portion 212 connected to the first connection conductor portion 213 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u21. In this way, by inclining the first upper conductor portion 211 and the first lower conductor portion 212 on opposite sides of the circumferential direction t with respect to the radial direction u, the pair of first connection conductor portions 213, 214 can be formed along the axial direction s respectively.

[0032] Also, in the present embodiment, two first upper conductor portions 211 adjacent to each other in the circumferential direction t and two first lower conductor portions 212 adjacent to each other in the circumferential direction t are each arranged with a predetermined interval therebetween. The interval is substantially the same, for example, on the inner peripheral edge 51A side and the outer peripheral edge 52A side. With this configuration, when viewed in the axial direction s, the dimension of the first connection conductor portion 214 along the circumferential direction t is larger than the dimension of the first connection conductor portion 213 along the circumferential direction t.

[0033] The plurality of first turns 21 are directly connected to each other between two first turns 21 adjacent in the circumferential direction t, and the induced current flowing through the secondary winding 2 flows through the plurality of first turns 21 in order. At this time, the first connection conductor portion 214 of each first turn 21 receives the induced current from the first lower conductor portion 212 of the first turn 21 adjacent to one side in the circumferential direction t. Then, this induced current flows from the first connection conductor portion 214 to the first lower conductor portion 212 via the first upper conductor portion 211 and the first connection conductor portion 213. That is, in the example shown in FIG. 13, the induced current flowing through each first turn 21 flows counterclockwise. Then, it is transmitted to the first turn 21 adjacent to the other side in the circumferential direction t. Thus, the induced current of the secondary winding 2 circulates through each of the plurality of first turns 21. Note that the direction of the induced current flowing through the first turn 21 may be opposite to the above example. That is, the first lower conductor portion 212 of each first turn 21 receives the induced current from the first connection conductor portion 214 of the first turn 21 adjacent to the other side in the circumferential direction t. Then, this induced current flows from the first lower conductor portion 212 to the first connection conductor portion 214 via the first connection conductor portion 213 and the first upper conductor portion 211. That is, in the example shown in FIG. 13, the induced current flowing through each first turn 21 may be configured to flow clockwise. Note that the direction of the induced current flowing through each first turn 21 is determined by the magnetic field generated by the primary winding 1.

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

[0035] In each second circumferential portion 22, the second upper conductor portion 221 and the second lower conductor portion 222 are separated from each other in the axial direction s as shown in FIG. 13. As shown in FIG. 12, the second upper conductor portion 221 and the second lower conductor portion 222 each extend from the inner peripheral edge 51B of the second cylindrical portion 5B toward the outer peripheral edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. The second upper conductor portion 221 and the second lower conductor portion 222 are each strip-shaped when viewed in the axial direction s. As shown in FIG. 13, each of the pair of second connection conductor portions 223, 224 extends along the axial direction s from the second upper conductor portion 221. The second connection conductor portion 223 is connected to the second lower conductor portion 222 of the same second circumferential portion 22. The second connection conductor portion 224 is connected to the second lower conductor portion 222 of the second circumferential portion 22 adjacent in the circumferential direction t. Each of the pair of second connection conductor portions 223, 224 is substantially orthogonal to the second upper conductor portion 221 and the second lower conductor portion 222. The second connection conductor portion 223 overlaps the inner peripheral edge 51B of the second cylindrical portion 5B when viewed in the axial direction s, and the second connection conductor portion 224 overlaps the outer peripheral edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. Each of the pair of second connection conductor portions 223, 224 is strip-shaped and extends in the axial direction s when viewed along the radial direction u.

[0036] In this embodiment, each second upper conductor portion 221 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and each second lower conductor portion 222 is inclined in the other direction of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 12, taking the radial direction u overlapping the second connection conductor portion 223 as the radial direction u22, the second upper conductor portion 221 connected to the second connection conductor portion 223 is inclined clockwise in the circumferential direction t with respect to the radial direction u22. Further, the second lower conductor portion 222 connected to the second connection conductor portion 223 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u22. In this way, by inclining the second upper conductor portion 221 and the second lower conductor portion 222 on opposite sides of the circumferential direction t with respect to the radial direction u, a pair of second connection conductor portions 223, 224 can be formed along the axial direction s respectively.

[0037] Also, in this embodiment, two second upper conductor portions 221 adjacent to each other in the circumferential direction t and two second lower conductor portions 222 adjacent to each other in the circumferential direction t are each arranged with a predetermined interval therebetween. The interval is substantially the same, for example, between the inner peripheral edge 51B side and the outer peripheral edge 52B side. With this configuration, when viewed in the axial direction s, the dimension along the circumferential direction t of the second connection conductor portion 224 is larger than the dimension along the circumferential direction t of the second connection conductor portion 223.

[0038] The plurality of second turn portions 22 are such that two adjacent second turn portions 22 in the circumferential direction t are directly connected, and the induced current flowing through the secondary winding 2 flows through the plurality of second turn portions 22 in sequence. At this time, the second connection conductor portion 224 of each second turn portion 22 receives the induced current from the second lower conductor portion 222 of the second turn portion 22 adjacent to one side in the circumferential direction t. Then, this induced current flows from the second connection conductor portion 224 through the second upper conductor portion 221 and the second connection conductor portion 223 to the second lower conductor portion 222. That is, in the example shown in FIG. 13, the induced current flowing through each second turn portion 22 flows counterclockwise. Therefore, the direction of the induced current flowing through each first turn portion 21 and the direction of the induced current flowing through each second turn portion 22 are the same when viewed along the circumferential direction t. Thus, the induced current of the secondary winding 2 circulates through each of the plurality of second turn portions 22. Note that the direction of the induced current flowing through the second turn portion 22 may be opposite to the above example. That is, the second lower conductor portion 222 of each second turn portion 22 receives the induced current from the second connection conductor portion 224 of the second turn portion 22 adjacent to the other side in the circumferential direction t. Then, this induced current flows from the second lower conductor portion 222 through the second connection conductor portion 223 and the second upper conductor portion 221 to the second connection conductor portion 224. That is, in the example shown in FIG. 13, the induced current flowing through each second turn portion 22 may be configured to flow clockwise. However, the direction of the induced current flowing through each first turn portion 21 and the direction of the induced current flowing through each second turn portion 22 are made the same when viewed along the circumferential direction t.

[0039] The connection portion 23 connects one of the plurality of first turn portions 21 and one of the plurality of second turn portions 22. For example, as shown in FIG. 14, the connection portion 23 is connected to and electrically connects the first upper conductor portion 211 of one of the plurality of first turn portions 21 and the second lower conductor portion 222 of one of the plurality of second turn portions 22.

[0040] The secondary winding 2 has a plurality of first circumferential portions 21 connected continuously along the circumferential direction t, and a plurality of second circumferential portions 22 connected continuously along the circumferential direction t. And these are connected by the connection portion 23. Therefore, the induced current of the secondary winding 2 circulates through the plurality of first circumferential portions 21, then enters the plurality of second circumferential portions 22 via the connection portion 23, and circulates through the plurality of second circumferential portions 22.

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

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

[0043] In the coil component A1, as shown in FIGS. 3 to 7, each first turn portion 11 of the primary winding 1 and each second turn portion 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, each first upper conductor portion 111 and each second upper conductor portion 221 overlap each other, and each first lower conductor portion 112 and each second lower conductor portion 222 overlap each other. When viewed in the radial direction u, each first connection conductor portion 113 and each second connection conductor portion 223 overlap each other, and each first connection conductor portion 114 and each second connection conductor portion 224 overlap each other. Also, as shown in FIGS. 3 to 7, each second turn portion 12 of the primary winding 1 and each first turn portion 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, each second upper conductor portion 121 and each first upper conductor portion 211 overlap each other, and each second lower conductor portion 122 and each first lower conductor portion 212 overlap each other. When viewed in the radial direction u, each second connection conductor portion 123 and each first connection conductor portion 213 overlap each other, and each second connection conductor portion 124 and each first connection conductor portion 214 overlap each other.

[0044] Next, the coil - embedded 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 - embedded substrate B1. FIG. 16 is a plan view showing the coil - embedded substrate B1. FIG. 17 is a cross - sectional view taken along line XVII - XVII of FIG. 16.

[0045] The coil - embedded substrate B1 is, for example, a printed circuit board. The coil - embedded substrate B1 is not limited to a printed circuit board and may be a semiconductor substrate or a ceramic substrate. The coil - embedded substrate B1 incorporates the coil component A1. The coil - embedded substrate B1 is, for example, rectangular in plan view. The coil - embedded 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, 9B.

[0046] The plurality of wiring layers 7 are each made of, for example, 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 plurality of 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 laminated from one side (the upper side in FIG. 17) to the other side (the lower side in FIG. 17) in the axial direction s and are spaced apart from each other. Wiring patterns are formed in 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 constitutes a plurality of first upper conductor portions 111 (the first turn portion 11 of the primary winding 1) and a plurality of first upper conductor portions 211 (the first turn portion 21 of the secondary winding 2).

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

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

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

[0052] As shown in FIG. 17, 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. Also, the separation distance in the axial direction s between the second wiring layer 72 and the third wiring layer 73 is greater than each of 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. Thereby, in the primary winding 1 of the coil component A1, the separation distance in the axial direction s between the first upper conductor portion 111 and the second upper conductor portion 121 is substantially the same as the separation distance in the axial direction s between the second lower conductor portion 122 and the first lower conductor portion 112. Also, the separation distance in the axial direction s between the second upper conductor portion 121 and the second lower conductor portion 122 is greater than each of the separation distance in the axial direction s between the first upper conductor portion 111 and the second upper conductor portion 121, and the separation distance in the axial direction s between the second lower conductor portion 122 and the first lower conductor portion 112. The same applies to 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. Each through electrode 79 in the present embodiment is, for example, columnar. The plurality of through electrodes 79 includes those that conduct between the first wiring layer 71 and the fourth wiring layer 74 and those that conduct between the second wiring layer 72 and the third wiring layer 73. The through electrode 79 that conducts between the first wiring layer 71 and the fourth wiring layer 74 constitutes a pair of first connection conductor portions 113, 114 (the first turn portion 11 of the primary winding 1) and a pair of first connection conductor portions 213, 214 (the first turn portion 21 of the secondary winding 2). Also, the through electrode 79 that conducts between the second wiring layer 72 and the third wiring layer 73 constitutes a pair of second connection conductor portions 123, 124 (the second turn portion 12 of the primary winding 1) and a pair of second connection conductor portions 223, 224 (the second turn portion 22 of the secondary winding 2).

[0054] In the coil-embedded substrate B1, the coil component A1 is constituted by each wiring pattern of the plurality of wiring layers 7 (the first wiring layer 71, the second wiring layer 72, the third wiring layer 73, the fourth wiring layer 74) and the plurality of through electrodes 79.

[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 an insulating resin such as glass epoxy resin. The material of the insulating member 8 is not limited to insulating resin, and a semiconductor material (for example, Si (silicon)) that has been subjected to an insulation treatment, or a ceramic or the like is adopted. Examples of the insulation treatment include doping with insulating impurities and forming an insulating oxide film.

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

[0057] The pair of terminals 9A are electrically connected to the primary winding 1 and are input terminals for the 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 terminal 9A is connected to the first upper conductor portion 111 (the first turn portion 11 of the primary winding 1), for example, as shown by the imaginary line in FIG. 14. The terminal wiring portion 90A of the other terminal 9A is connected to the second lower conductor portion 122 (the second turn portion 12 of the primary winding 1), for example, as shown by the 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 through the primary winding 1. Thereby, a magnetic field is generated from the primary winding 1.

[0058] The pair of terminals 9B are electrically connected to the secondary winding 2 and are the output terminals of the induced current of 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 terminal 9B is connected to the first lower conductor portion 212 (the first turn portion 21 of the secondary winding 2), for example, as indicated by the imaginary line in FIG. 14. The terminal wiring portion 90B of the other terminal 9B is connected to the second upper conductor portion 221 (the second turn portion 22 of the secondary winding 2), for example, as indicated by the imaginary line in FIG. 14. An induced current is generated in the secondary winding 2 by the magnetic field generated by the primary winding 1, and a potential difference is generated between the pair of terminals 9B.

[0059] In the examples shown in FIGS. 15 and 16, all of the pair of terminals 9A and the pair of terminals 9B are formed so as to be exposed from the upper surface of the insulating member 8 (the surface facing one of the axial directions s), but the present invention is not limited to this. The pair of terminals 9A and the pair of terminals 9B can be appropriately changed according to the specifications of the coil-embedded substrate B1 as to whether they are exposed from the upper surface of the insulating member 8 or from the lower surface of the insulating member 8 (the surface facing the other of the axial directions s). In this case, the terminal wiring portion 90A of each terminal 9A and the terminal wiring portion 90B of each terminal 9B are appropriately changed from the example shown in FIG. 14.

[0060] The functions and effects of the coil component A1 and the coil-embedded substrate B1 according to the first embodiment are as follows.

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

[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 face the same direction when viewed in the first direction (circumferential direction t). According to this configuration, the magnetic flux generated by the input current flowing through each first winding portion 11 and the magnetic flux generated by the input current flowing through each second winding portion 12 face the same direction and reinforce each other inside the plurality of second winding portions 12, that is, inside the second cylindrical portion 5B. Therefore, in the coil component A1, since the magnetic flux inside the second cylindrical portion 5B increases, the inductance value can be improved.

[0063] The coil component A1 does not include a magnetic core for the primary winding 1 and the secondary winding 2, and is in an air-core form. In a coil component provided with a magnetic core, when the input current input to the primary winding 1 is in a high-frequency band, the magnetic core causes energy loss. Therefore, even when the input current to the primary winding 1 is in a high-frequency band, the coil component A1 does not include a magnetic core, so that energy loss due to the magnetic core can be suppressed.

[0064] In the coil component A1, in the circumferential direction t, the plurality of first winding portions 11 of the primary winding 1 and the plurality of first winding portions 21 of the secondary winding 2 are alternately arranged. Also, inside each first winding portion 11 of the primary winding 1, each second winding portion 22 of the secondary winding 2 is arranged, and inside each first winding portion 21 of the secondary winding 2, each second winding portion 12 of the primary winding 1 is arranged. According to this configuration, the coupling between the primary winding 1 and the secondary winding 2 becomes good. Thereby, magnetic flux leakage due to poor coupling between the primary winding 1 and the secondary winding 2 can be suppressed.

[0065] The coil-embedded 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 laminated in the axial direction s. Wiring patterns are formed in 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 A1 is constituted by these wiring patterns. According to this configuration, for example, the coil component A1 is formed by the manufacturing process of a printed circuit board (or a semiconductor substrate or a ceramic substrate). Therefore, the coil-embedded substrate B1 facilitates the manufacture of the coil component A1 having a complex wiring structure. Further, since the coil-embedded substrate B1 constitutes the coil component A1 by the wiring patterns in the plurality of wiring layers 7, the coil component A1 can be made thinner.

[0066] In the first embodiment, an example is shown in which each first turn portion 11 of the primary winding 1 and each second turn portion 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, but the present invention is not limited to this. For example, each first turn portion 11 of the primary winding 1 may partially overlap with each second turn portion 12 of the primary winding 1 rather than each second turn portion 22 of the secondary winding 2 when viewed in the axial direction s and also partially overlap when viewed in the radial direction u. At this time, each first turn portion 21 of the secondary winding 2 and each second turn portion 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. However, the coil component A1 is more preferable than the coil component according to this modification in enhancing the coupling coefficient between the primary winding 1 and the secondary winding 2.

[0067] In the first embodiment, an example is shown in which a plurality of first turn portions 11 continuously connected along the circumferential direction t and a plurality of second turn portions 12 continuously connected along the circumferential direction t are connected by a connection portion 13, but the present invention is not limited to this. For example, each first turn portion 11 adjacent to each other in the circumferential direction t and each second turn portion 12 may be connected. That is, in the primary winding 1, a configuration may be adopted in which an input current alternately flows through each first turn portion 11 and each second turn portion 12. Similarly, in the secondary winding 2, a configuration may be adopted in which an induced current alternately flows through each first turn portion 21 and each second turn portion 22 in the secondary winding 2.

[0068] In the first embodiment, in each first winding portion 11 (primary winding 1), an example is shown in which the first upper conductor portion 111 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and the first lower conductor portion 112 is inclined in the other direction of the circumferential direction t with respect to the radial direction u, but the present invention is not limited to this. In each first winding portion 11, the first upper conductor portion 111 may not be inclined in one direction of the circumferential direction t. In this case, in order for the pair of first connection conductor portions 113 and 114 to have a shape along the axial direction s, the inclination angle of the first lower conductor portion 112 with respect to the circumferential direction t with respect to the radial direction u increases. Conversely, the first lower conductor portion 112 may not be inclined in the other direction of the circumferential direction t. In this case, in order for the pair of first connection conductor portions 113 and 114 to have a shape along the axial direction s, the inclination angle of the first upper conductor portion 111 with respect to the circumferential direction t with respect to the radial direction u increases. Further, both the first upper conductor portion 111 and the first lower conductor portion 112 may not be inclined in the circumferential direction t. In this case, the pair of first connection conductor portions 113 and 114 are inclined with respect to the axial direction s. Such a modified example is the same for the second upper conductor portion 121 and the second lower conductor portion 122 in each second winding portion 12 (primary winding 1), the first upper conductor portion 211 and the first lower conductor portion 212 in each first winding portion 21 (secondary winding 2), and the second upper conductor portion 221 and the second lower conductor portion 222 in each second winding portion 22 (secondary winding 2).

[0069] In the first embodiment, in each first winding portion 11 (primary winding 1), an example was shown in which, when viewed in the axial direction s, the dimension along the circumferential direction t of the first connection conductor portion 114 is larger than the dimension along the circumferential direction t of the first connection conductor portion 113, but the present invention is not limited to this. These dimensions may be substantially the same. In this case, the predetermined intervals provided between two adjacent first upper conductor portions 111 in the circumferential direction t and between two adjacent first lower conductor portions 112 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. Such a modified example is the same for a pair of second connection conductor portions 123 and 124 in each second winding portion 12 (primary winding 1), a pair of first connection conductor portions 213 and 214 in each first winding portion 21 (secondary winding 2), and a pair of second connection conductor portions 223 and 224 in each second winding portion 22 (secondary winding 2).

[0070] In the coil component A2 according to the second embodiment, with reference to FIGS. 18 to 24, it will be described. The coil component A2 is, for example, an inductor and includes a winding 3. The coil component A2 may include a magnetic core, but it is preferably in a hollow form without a magnetic core. Similar to the coil component A1, the coil component A2 is, for example, toroidal in appearance. The overall shape of the coil component A2 is constituted by various combinations of the above planar shape and the above cross-sectional shape, similar to the overall shape of the coil component A1. In the second embodiment, a case where the planar shape is an annular shape and the cross-sectional shape is a rectangular annular shape will be described as an example. 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. Also, the above 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 component A2. FIG. 19 is a partially enlarged view obtained by enlarging a part of FIG. 18. FIG. 20 is a plan view showing the coil component A2. FIG. 21 is an end face view of a cut portion along line XXI-XXI of FIG. 20. FIG. 22 is a bottom view showing the coil component A2. FIG. 23 is a view obtained by omitting a part (a part of the first cylindrical portion 5A described later) in the perspective view shown in FIG. 18. In FIG. 23, a connecting portion 33 (described later) is omitted. FIG. 24 is a schematic view when the winding 3 is viewed along the circumferential direction t.

[0072] In the coil component A2, the winding 3 is wound double. 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. The first cylindrical portion 5A and the second cylindrical portion 5B are each toroidal in shape, similar to the first embodiment. 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 appearance of the coil component A1. The first cylindrical portion 5A and the second cylindrical portion 5B each have an annular planar shape, for example, and share a common central axis. That is, the central axis in the plan view of the first cylindrical portion 5A and the central axis in the plan view of the second cylindrical portion 5B substantially coincide. The direction in which this central axis extends corresponds to the axial direction s. Also, the first cylindrical portion 5A and the second cylindrical portion 5B each have a rectangular annular cross-sectional shape, for example.

[0073] The winding 3 generates a magnetic field by an input current from the outside. The winding 3 is configured in the same manner as the primary winding 1 according to the first embodiment. As shown in FIGS. 18 to 24, the winding 3 includes a plurality of first circumferential portions 31, a plurality of second circumferential portions 32, and a connecting portion 33.

[0074] As shown in FIG. 24, each of the plurality of first circumferential portions 31 has a rectangular annular shape, for example, when viewed along the circumferential direction t. As shown in FIGS. 18 to 20, FIG. 22, and FIG. 23, the plurality of first circumferential portions 31 are arranged in the circumferential direction t when viewed in the axial direction s. Each of the plurality of first circumferential portions 31 includes a first upper conductor portion 311, a first lower conductor portion 312, and a pair of first connecting conductor portions 313 and 314, as shown in FIG. 24.

[0075] In each first circumferential portion 31, the first upper conductor portion 311 and the first lower conductor portion 312 are separated 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 are each strip-shaped when viewed in the axial direction s. Each of the pair of first connection conductor portions 313, 314 extends along the axial direction s from the first upper conductor portion 311 as shown in FIG. 24. The first connection conductor portion 313 is connected to the first lower conductor portion 312 of the same first circumferential portion 31. The first connection conductor portion 314 is connected to the first lower conductor portion 312 of the first circumferential portion 31 adjacent in the circumferential direction t. Each of the pair of first connection conductor portions 313, 314 is substantially orthogonal to the first upper conductor portion 311 and the first lower conductor portion 312. The first connection conductor portion 313 overlaps the inner peripheral edge 51A of the first cylindrical portion 5A when viewed in the axial direction s, and the first connection conductor portion 314 overlaps the outer peripheral edge 52A of the first cylindrical portion 5A when viewed in the axial direction s. Each of the pair of first connection conductor portions 313, 314 is strip-shaped and extends in the axial direction s when viewed along the radial direction u.

[0076] In the present embodiment, each first upper conductor portion 311 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and each first lower conductor portion 312 is inclined in the other direction of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 20, taking the radial direction u overlapping the first connection conductor portion 313 as the radial direction u3, the first upper conductor portion 311 connected to the first connection conductor portion 313 is inclined clockwise in the circumferential direction t with respect to the radial direction u3. Also, the first lower conductor portion 312 connected to the first connection conductor portion 313 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u3. In this way, by inclining the first upper conductor portion 311 and the first lower conductor portion 312 on opposite sides of the circumferential direction t with respect to the radial direction u, the pair of first connection conductor portions 313, 314 can be formed along the axial direction s respectively.

[0077] Also, in the present embodiment, two first upper conductor portions 311 adjacent to each other in the circumferential direction t and two first lower conductor portions 312 adjacent to each other in the circumferential direction t are each arranged with a predetermined interval therebetween. The interval is substantially the same, for example, between the inner peripheral edge 51A side and the outer peripheral edge 52A side. With this configuration, when viewed in the axial direction s, the dimension of the first connection conductor portion 314 along the circumferential direction t is larger than the dimension of the first connection conductor portion 313 along the circumferential direction t.

[0078] The plurality of first winding portions 31 are such that two first winding portions 31 adjacent to each other in the circumferential direction t are directly connected, and the input current flowing through the winding 3 flows through the plurality of first winding portions 31 in order. At this time, the first connection conductor portion 314 of each first winding portion 31 receives the input current from the first lower conductor portion 312 of the first winding portion 31 adjacent to one side in the circumferential direction t. Then, this input current flows from the first connection conductor portion 314 to the first lower conductor portion 312 via the first upper conductor portion 311 and the first connection conductor portion 313. That is, in the example shown in FIG. 24, the input current flowing through each first winding portion 31 flows counterclockwise. Then, it is transmitted to the first winding portion 11 adjacent to the other side in the circumferential direction t. In this way, the input current of the winding 3 circulates through each of the plurality of first winding portions 31. Note that the direction of the input current flowing through the first winding portion 31 may be opposite to the above example. That is, the first lower conductor portion 312 of each first winding portion 31 receives the input current from the first connection conductor portion 314 of the first winding portion 31 adjacent to the other side in the circumferential direction t. Then, this input current flows from the first lower conductor portion 312 to the first connection conductor portion 314 via the first connection conductor portion 313 and the first upper conductor portion 311. That is, in the example shown in FIG. 24, the input current flowing through each first winding portion 31 may be configured to flow clockwise.

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

[0080] In each second circumferential portion 32, the second upper conductor portion 321 and the second lower conductor portion 322 are spaced apart in the axial direction s as shown in FIG. 24. The second upper conductor portion 321 and the second lower conductor portion 322 each extend from the inner peripheral edge 51B to the outer peripheral edge 52B of the second cylindrical portion 5B when viewed in the axial direction s as shown in FIGS. 20 and 22. The second upper conductor portion 321 and the second lower conductor portion 322 are each strip-shaped when viewed in the axial direction s. Each of the pair of second connection conductor portions 323 and 324 extends along the axial direction s from the second upper conductor portion 321 as shown in FIG. 24. The second connection conductor portion 323 is connected to the second lower conductor portion 322 of the same second circumferential portion 32. The second connection conductor portion 324 is connected to the second lower conductor portion 322 of the second circumferential portion 32 adjacent in the circumferential direction t. Each of the pair of second connection conductor portions 323 and 324 is substantially orthogonal to the second upper conductor portion 321 and the second lower conductor portion 322. The second connection conductor portion 323 overlaps the inner peripheral edge 51B of the second cylindrical portion 5B when viewed in the axial direction s, and the second connection conductor portion 324 overlaps the outer peripheral edge 52B of the second cylindrical portion 5B when viewed in the axial direction s. Each of the pair of second connection conductor portions 323 and 324 is strip-shaped and extends in the axial direction s when viewed along the radial direction u.

[0081] In the present embodiment, each second upper conductor portion 321 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and each second lower conductor portion 322 is inclined in the other direction of the circumferential direction t with respect to the radial direction u. In the example shown in FIG. 20, taking the radial direction u overlapping the second connection conductor portion 323 as the radial direction u3, the second upper conductor portion 321 connected to the second connection conductor portion 323 is inclined clockwise in the circumferential direction t with respect to the radial direction u3. Further, the second lower conductor portion 322 connected to the second connection conductor portion 323 is inclined counterclockwise in the circumferential direction t with respect to the radial direction u3. In this way, by inclining the second upper conductor portion 321 and the second lower conductor portion 322 on opposite sides of the circumferential direction t with respect to the radial direction u, a pair of second connection conductor portions 323 and 324 can be formed along the axial direction s, respectively.

[0082] Also, in the present embodiment, two second upper conductor portions 321 adjacent to each other in the circumferential direction t and two second lower conductor portions 322 adjacent to each other in the circumferential direction t are arranged with a predetermined interval therebetween. The interval is substantially the same, for example, between the inner peripheral edge 51B side and the outer peripheral edge 52B side. With this configuration, when viewed in the axial direction s, the dimension along the circumferential direction t of the second connection conductor portion 324 is larger than the dimension along the circumferential direction t of the second connection conductor portion 323.

[0083] The plurality of second turns 32 are such that two adjacent second turns 32 in the circumferential direction t are directly connected, and the input current flowing through the winding 3 flows through the plurality of second turns 32 in sequence. At this time, the second connection conductor portion 324 of each second turn 32 receives the input current from the second lower conductor portion 322 of the second turn 32 adjacent to one side in the circumferential direction t. Then, this input current flows from the second connection conductor portion 324 through the second upper conductor portion 321 and the second connection conductor portion 323 to the second lower conductor portion 322. That is, in the example shown in FIG. 24, the input current flowing through each second turn 32 flows counterclockwise. Therefore, the direction of the input current flowing through each first turn 31 and the direction of the input current flowing through each second turn 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 plurality of second turns 32. Note that the direction of the input current flowing through the second turn 32 may be opposite to the above example. That is, the second lower conductor portion 322 of each second turn 32 receives the input current from the second connection conductor portion 324 of the second turn 32 adjacent to the other side in the circumferential direction t. Then, this input current flows from the second lower conductor portion 322 through the second connection conductor portion 323 and the second upper conductor portion 321 to the second connection conductor portion 324. That is, in the example shown in FIG. 24, the input current flowing through each second turn 32 may be configured to flow clockwise. However, the direction of the input current flowing through each first turn 31 and the direction of the input current flowing through each second turn 32 are made the same when viewed along the circumferential direction t.

[0084] As shown in FIG. 19, the connection portion 33 connects one of the plurality of first turns 31 and one of the plurality of second turns 32. For example, the connection portion 33 is connected to the first lower conductor portion 312 of one of the plurality of first turns 31 and the second upper conductor portion 321 of one of the plurality of second turns 32, and conducts them.

[0085] The winding 3 has a plurality of first winding portions 31 connected continuously along the circumferential direction t, and a plurality of second winding portions 32 connected continuously along the circumferential direction t. And these are connected by the connection portion 33. Therefore, the input current of the winding 3 circulates through the plurality of first winding portions 31, then enters the plurality of second winding portions 32 via the connection portion 33, and circulates through the plurality of second winding portions 32.

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

[0087] In the coil component A2, as shown in FIGS. 18 to 24, each first winding portion 31 and each second winding portion 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, each first upper conductor portion 311 and each second upper conductor portion 321 overlap each other, and each first lower conductor portion 312 and each second lower conductor portion 322 overlap each other. When viewed in the radial direction u, each first connection conductor portion 313 and each second connection conductor portion 323 overlap each other, and each first connection conductor portion 314 and each second connection conductor portion 324 overlap each other.

[0088] Next, the coil - built - in substrate B2 incorporating the coil component A2 will be described with reference to FIGS. 25 to 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 of 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 not limited to a printed circuit board and may also 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 a plurality of wiring layers 7, a plurality of through - electrodes 79, an insulating member 8, and a pair of terminals 9C.

[0090] Also in the substrate B2 with a built-in coil, as shown in FIG. 27, the plurality of 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 each having a wiring pattern formed thereon.

[0091] As shown in FIG. 27, a plurality of first upper conductor portions 311 are formed by the wiring pattern in the first wiring layer 71. A plurality of second upper conductor portions 321 are formed by the wiring pattern in the second wiring layer 72. A plurality of second lower conductor portions 322 are formed by the wiring pattern in the third wiring layer 73. A plurality of first lower conductor portions 312 are formed by the wiring pattern in the fourth wiring layer 74.

[0092] As shown in FIG. 27, also in the present embodiment, 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. Also, the separation distance in the axial direction s between the second wiring layer 72 and the third wiring layer 73 is larger than each of 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. Thereby, in the winding 3 of the coil component A2, the separation distance in the axial direction s between the first upper conductor portion 311 and the second upper conductor portion 321 is substantially the same as the separation distance in the axial direction s between the second lower conductor portion 322 and the first lower conductor portion 312. Also, the separation distance in the axial direction s between the second upper conductor portion 321 and the second lower conductor portion 322 is larger than each of 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] Also, a pair of first connection conductor portions 313, 314 (first turn portion 31) are formed by a through electrode 79 that conducts the first wiring layer 71 and the fourth wiring layer 74. Also, a pair of second connection conductor portions 323, 324 (second turn portion 32) are formed by a through electrode 79 that conducts the second wiring layer 72 and the third wiring layer 73.

[0094] In the coil-embedded substrate B2, the coil component A2 is constituted by each wiring pattern of a plurality of wiring layers 7 (first wiring layer 71, second wiring layer 72, third wiring layer 73, fourth wiring layer 74) and a plurality of through electrodes 79.

[0095] A pair of terminals 9C are electrically connected to the winding 3 and are input terminals for 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 turn portion 31). The terminal wiring portion 90C of the other terminal 9C is connected to, for example, the second lower conductor portion 322 (second turn portion 32). When a voltage is applied between the pair of terminals 9C, an input current flows from one terminal 9C through the winding 3 to the other terminal 9C. Thereby, a magnetic field is generated from the winding 3.

[0096] In the example shown in FIG. 25, each of the pair of terminals 9C is formed so as to be exposed from the upper surface of the insulating member 8 (the surface facing one of the axial directions s), but is not limited thereto. Each of the pair of terminals 9C can be appropriately changed according to the specifications of the coil-embedded substrate B2 as to whether it is exposed from the upper surface of the insulating member 8 or from the lower surface of the insulating member 8 (the surface facing the other of the axial directions s).

[0097] The functions and effects of the coil component A2 and the coil-embedded substrate B2 according to the second embodiment are as follows.

[0098] The coil component A2 includes a winding 3 through which an input current from the outside flows. The winding 3 includes a plurality of first circumferential portions 31 each of which is annular when viewed in the first direction (circumferential direction t). According to this configuration, in each first circumferential portion 31, for example, the input currents flowing through portions facing each other in the axial direction s are in opposite directions. Therefore, the magnetic fluxes generated by these portions face opposite sides outside each first circumferential portion 31 and cancel each other out. The plurality of first circumferential portions 31 are a first cylindrical portion 5A that forms the appearance of the coil component A2. Therefore, the coil component A2 can suppress magnetic flux leakage to the outside because the magnetic flux outside each first circumferential portion 31 (first cylindrical portion 5A) decreases.

[0099] In the coil component A2, the winding 3 includes a plurality of first circumferential portions 31 and a plurality of second circumferential portions 32. The direction of the input current flowing through each of the plurality of first circumferential portions 31 and the direction of the input current flowing through each of the plurality of second circumferential portions 32 face the same direction when viewed in the first direction (circumferential direction t). According to this configuration, the magnetic flux generated by the input current flowing through each first circumferential portion 31 and the magnetic flux generated by the input current flowing through each second circumferential portion 32 face the same direction and reinforce each other inside the plurality of second circumferential portions 32, that is, inside the second cylindrical portion 5B. Therefore, the coil component A2 can improve the inductance value because the magnetic flux inside the second cylindrical portion 5B increases.

[0100] The coil component A1 does not include a magnetic core with respect to the winding 3 and is in an air-core form. In a coil component with a magnetic core, when the input current input to the winding 3 is in a high-frequency band, the magnetic core causes energy loss. Therefore, the coil component A2 can suppress energy loss caused by the magnetic core because it does not include a magnetic core even when the input current of the winding 3 is in a high-frequency band.

[0101] In the coil-embedded substrate B2, wiring patterns are formed in 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 constituted by these wiring patterns. According to this configuration, for example, the coil component A2 is formed by the manufacturing process of a printed circuit board (or a semiconductor substrate or a ceramic substrate). Therefore, the coil-embedded substrate B2 facilitates the manufacture of the coil component A2 having a complex wiring structure. Further, since the coil-embedded substrate B2 constitutes the coil component A2 by the wiring patterns in the plurality of wiring layers 7, the height of the coil component A2 can be reduced.

[0102] In the second embodiment, an example in which each first circumferential portion 31 and each second circumferential portion 32 overlap when viewed in the axial direction s is shown, but the present invention is not limited to this. For example, each first circumferential portion 31 and each second circumferential portion 32 may partially overlap or may not overlap when viewed in the axial direction s. However, the coil component A2 is more preferable than the coil component according to the modification in terms of improving the inductance value.

[0103] In the second embodiment, an example in which in each first circumferential portion 31, the first upper conductor portion 311 is inclined in one direction of the circumferential direction t with respect to the radial direction u, and the first lower conductor portion 312 is inclined in the other direction of the circumferential direction t with respect to the radial direction u is shown, but the present invention is not limited to this. In each first circumferential portion 31, the first upper conductor portion 311 may not be inclined in one direction of the circumferential direction t. In this case, since the pair of first connection conductor portions 313 and 314 have a shape along the axial direction s, the inclination angle of the first lower conductor portion 312 with respect to the circumferential direction t with respect to the radial direction u increases. Conversely, the first lower conductor portion 312 may not be inclined in the other direction of the circumferential direction t. In this case, since the pair of first connection conductor portions 313 and 314 have a shape along the axial direction s, the inclination angle of the first upper conductor portion 311 with respect to the circumferential direction t with respect to the radial direction u increases. Further, both the first upper conductor portion 311 and the first lower conductor portion 312 may not be inclined in the circumferential direction t. In this case, the pair of first connection conductor portions 313 and 314 are inclined with respect to the axial direction s. Such a modification is the same for the second upper conductor portion 321 and the second lower conductor portion 322 in each second circumferential portion 32.

[0104] In the second embodiment, in each first turn portion 31, an example is shown in which, when viewed in the axial direction s, the dimension along the circumferential direction t of the first connection conductor portion 314 is larger than the dimension along the circumferential direction t of the first connection conductor portion 313. However, the present invention is not limited to this. These dimensions may be substantially the same. In this case, the predetermined intervals provided between two adjacent first upper conductor portions 311 in the circumferential direction t and between two adjacent first lower conductor portions 312 in the circumferential direction t are such that, in the radial direction u, the side closer to the outer peripheral edge 52A is relatively large and the side closer to the inner peripheral edge 51A is relatively small. Such a modified example is the same for a pair of second connection conductor portions 323 and 324 in each second turn portion 32.

[0105] In the first embodiment and the second embodiment, in each coil-embedded substrate B1, B2, an example is shown in which a plurality of through electrodes 79 are each formed in a columnar shape. However, the present invention is not limited to this. For example, each through electrode 79 may be formed of a so-called through via. The through via is, for example, circular in plan view. Also, a plurality of through vias may be provided for each through electrode 79.

[0106] In the first embodiment and the second embodiment, an example is shown in which each coil component A1, A2 has a toroidal shape in appearance. However, the present invention is not limited to this. For example, each coil component A1 may have a solenoid shape. In the present disclosure, the solenoid shape means that the planar shape is not annular like the toroidal shape, and includes not only those wound linearly but also those wound in a curved shape. In this modified example, a plurality of first turn portions 11 and a plurality of second turn portions 12 of the primary winding 1 and a plurality of first turn portions 21 and a plurality of second turn portions 22 of the secondary winding 2, or a plurality of first turn portions 31 and second turn portions 32 of the winding 3, are arranged linearly or in a curved shape. However, in the case of the solenoid shape, since the planar shape is not annular, it is more effective to suppress magnetic flux leakage when configured in a toroidal shape like each coil component A1, A2.

[0107] In the first and second embodiments, an example in which each coil component A1, A2 is constituted by wiring patterns in a plurality of wiring layers 7 of the substrate B1 with built-in coils has been shown, but the present invention is not limited thereto. For example, a linear or plate-like lead wire may be wound to form the primary winding 1 and the secondary winding 2 (or winding 3).

[0108] The coil component and the substrate with built-in coil according to the present disclosure are not limited to the above-described embodiments. The specific configuration of each part of the coil component and the substrate with built-in coil of the present disclosure can be freely designed in various ways. The present disclosure includes the embodiments described in the following supplementary notes. Supplementary Note 1. A primary winding that generates a magnetic field by an input current from the outside, A secondary winding through which an induced current generated by the magnetic field flows, and are provided with, each of the primary windings includes a plurality of primary-side first circumferential portions and a plurality of primary-side second circumferential portions that are annular when viewed in the first direction, each of the secondary windings includes a plurality of secondary-side first circumferential portions and a plurality of secondary-side second circumferential portions that are annular when viewed in the first direction, the plurality of primary-side first circumferential portions and the plurality of secondary-side first circumferential portions are alternately arranged in the first direction to form a first cylindrical portion, the plurality of primary-side second circumferential portions and the plurality of secondary-side second circumferential 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 circumferential portions and the direction of the input current flowing through each of the plurality of primary-side second circumferential portions face the same direction. Supplementary Note 2. Each of the plurality of primary-side first circumferential portions includes a primary-side first upper conductor portion and a primary-side first lower conductor portion that are separated in the thickness direction orthogonal to the first direction, each of the plurality of primary-side second circumferential portions includes a primary-side second upper conductor portion and a primary-side second lower conductor portion that are separated in the thickness direction, Each of the plurality of secondary-side first turn portions includes a secondary-side first upper conductor portion and a secondary-side first lower conductor portion that are spaced apart in the thickness direction. Each of the plurality of secondary-side second turn portions includes a secondary-side second upper conductor portion and a secondary-side second lower conductor portion that are spaced apart in the thickness direction, the coil component according to appended note 1. Appended note 3. The primary-side first upper conductor portion and the secondary-side first upper conductor portion overlap when viewed in the first direction. The primary-side first lower conductor portion and the secondary-side first lower conductor portion overlap when viewed in the first direction, the coil component according to appended note 2. Appended note 4. The primary-side second upper conductor portion and the secondary-side second upper conductor portion overlap when viewed in the first direction. The primary-side second lower conductor portion and the secondary-side second lower conductor portion overlap when viewed in the first direction, the coil component according to appended note 3. Appended note 5. 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 each of 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, the coil component according to appended note 4. Appended note 6. The primary-side first upper conductor portion and the secondary-side second upper conductor portion overlap when viewed in the thickness direction. The primary-side first lower conductor portion and the secondary-side second lower conductor portion overlap when viewed in the thickness direction, the coil component according to any one of appended notes 3 to 5. Appended note 7. The primary-side second upper conductor portion and the secondary-side first upper conductor portion overlap when viewed in the thickness direction. The primary-side second lower conductor portion and the secondary-side first lower conductor portion overlap when viewed in the thickness direction, the coil component according to appended note 6. Appended note 8. Each of the plurality of primary-side first turn portions includes a pair of primary-side first connection conductor portions each extending in the thickness direction from the primary-side first upper conductor portion. One of the pair of primary-side first connection 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 connection conductor portions that each extend in the thickness direction from the primary-side second upper conductor portion. One of the pair of primary-side second connection conductor portions is connected to the primary-side second lower conductor portion, and is the coil component according to any one of Appendices 3 to 7. Appendix 9. The other of the pair of primary-side first connection conductor portions is connected to the primary-side first lower conductor portion of the adjacent primary-side first winding portion. The other of the pair of primary-side second connection conductor portions is connected to the primary-side second lower conductor portion of the adjacent primary-side second winding portion, and is the coil component according to Appendix 8. Appendix 10. The primary winding further includes a primary-side connection portion that electrically connects one of the plurality of primary-side first winding portions and one of the plurality of primary-side second winding portions, and is the coil component according to Appendix 9. Appendix 11. Each of the plurality of secondary-side first winding portions includes a pair of secondary-side first connection conductor portions that each extend in the thickness direction from the secondary-side first upper conductor portion. One of the pair of secondary-side first connection 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 connection conductor portions that each extend in the thickness direction from the secondary-side second upper conductor portion. One of the pair of secondary-side second connection conductor portions is connected to the secondary-side second lower conductor portion, and is the coil component according to Appendix 9 or Appendix 10. Appendix 12. The other of the pair of secondary-side first connection conductor portions is connected to the secondary-side first lower conductor portion of the adjacent secondary-side first winding portion. The other of the pair of secondary-side second connection conductor portions is connected to the secondary-side second lower conductor portion of the adjacent secondary-side second winding portion, and is the coil component according to Appendix 11. Appendix 13. The secondary winding further includes a secondary-side connection portion that electrically connects one of the plurality of secondary-side first winding portions and one of the plurality of secondary-side second winding portions, the coil component according to appended note 12. Appended note 14. The first cylindrical portion and the second cylindrical portion are each annular with the first direction as the circumferential direction when viewed in the thickness direction, the coil component according to any one of appended notes 2 to 13. Appended note 15. 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, the coil component according to appended note 14. Appended note 16. 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, the coil component according to appended note 15. Appended note 17. The primary-side first upper conductor portion and the secondary-side first upper conductor portion each incline in one direction of 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, The primary-side first lower conductor portion and the secondary-side first lower conductor portion each incline in the other direction of 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, the coil component according to appended note 15 or 16. Appended note 18. 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, the coil component according to any one of appended notes 14 to 17. Appended note 19. 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, the coil component according to appended note 18. Appended note 20. The primary-side second upper conductor part and the secondary-side second upper conductor part are each inclined in one direction in the circumferential direction of the second cylindrical part with respect to the radial direction of the second cylindrical part when viewed in the thickness direction. The primary-side second lower conductor part and the secondary-side second lower conductor part are each inclined in the other direction in the circumferential direction of the second cylindrical part with respect to the radial direction of the second cylindrical part when viewed in the thickness direction, the coil component according to any one of Appendices 18 or 19. Appendix 21. It includes windings that generate a magnetic field by an input current from the outside. Each of the windings includes a plurality of first circumferential parts and a plurality of second circumferential parts that are annular when viewed in the first direction. The plurality of first circumferential parts are arranged in the first direction and constitute a first cylindrical part. The plurality of second circumferential parts are arranged in the first direction and constitute a second cylindrical part. The second cylindrical part is located inside the first cylindrical part when viewed in the first direction. Each of the first cylindrical part and the second cylindrical part is annular when viewed in the thickness direction orthogonal to the first direction. The direction of the input current flowing through each of the plurality of first circumferential parts and the direction of the input current flowing through each of the plurality of second circumferential parts face the same direction, the coil component. Appendix 22. A coil-embedded substrate incorporating the coil component according to any one of Appendices 2 to 21, A plurality of wiring layers laminated in the thickness direction, A plurality of insulating layers interposed between the plurality of wiring layers in the thickness direction, and includes The coil component is constituted by a wiring pattern in the plurality of wiring layers, the coil-embedded substrate. Appendix 23. The coil component is a transformer, the coil-embedded substrate according to Appendix 22.

Explanation of Signs

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

Claims

1. A primary winding that generates a magnetic field by an input current from the outside, A secondary winding through which an induced current generated by the magnetic field flows, Comprising, The primary winding includes a plurality of primary-side first circumferential portions and a plurality of primary-side second circumferential portions that are each annular when viewed in the first direction, The secondary winding includes a plurality of secondary-side first circumferential portions and a plurality of secondary-side second circumferential portions that are each annular when viewed in the first direction, The plurality of primary-side first circumferential portions and the plurality of secondary-side first circumferential portions are alternately arranged in the first direction to form a first cylindrical portion, The plurality of primary-side second circumferential portions and the plurality of secondary-side second circumferential 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 circumferential portions and the direction of the input current flowing through each of the plurality of primary-side second circumferential portions face the same direction.

2. Each of the plurality of primary-side first circumferential portions includes a primary-side first upper conductor portion and a primary-side first lower conductor portion that are spaced apart in a thickness direction orthogonal to the first direction, Each of the plurality of primary-side second circumferential portions includes a primary-side second upper conductor portion and a primary-side second lower conductor portion that are spaced apart in the thickness direction, Each of the plurality of secondary-side first circumferential portions includes a secondary-side first upper conductor portion and a secondary-side first lower conductor portion that are spaced apart in the thickness direction, The coil component according to claim 1, wherein each of the plurality of secondary-side second circumferential portions includes a secondary-side second upper conductor portion and a secondary-side second lower conductor portion that are spaced apart in the thickness direction.

3. The primary-side first upper conductor portion and the secondary-side first upper conductor portion overlap when viewed in the first direction, 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.

4. The primary-side second upper conductor portion and the secondary-side second upper conductor portion overlap when viewed in the first direction, 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.

5. In the thickness direction, the separation distance between the primary-side second upper conductor portion and the primary-side second lower conductor portion is greater than each of the separation distance between the primary-side first upper conductor portion and the primary-side second upper conductor portion and the separation distance between the primary-side second lower conductor portion and the primary-side first lower conductor portion. The coil component according to claim 4.

6. The first upper conductor portion on the primary side and the second upper conductor portion on the secondary side overlap when viewed in the thickness direction. The first lower conductor portion on the primary side and the second lower conductor portion on the secondary side overlap when viewed in the thickness direction. The coil component according to any one of claims 3 to 5.

7. The second upper conductor portion on the primary side and the first upper conductor portion on the secondary side overlap when viewed in the thickness direction. The second lower conductor portion on the primary side and the first lower conductor portion on the secondary side overlap when viewed in the thickness direction. The coil component according to claim 6.

8. Each of the plurality of first circumferential portions on the primary side includes a pair of first connection conductor portions each extending from the first upper conductor portion on the primary side in the thickness direction. One of the pair of first connection conductor portions on the primary side is connected to the first lower conductor portion on the primary side. Each of the plurality of second circumferential portions on the primary side includes a pair of second connection conductor portions each extending from the second upper conductor portion on the primary side in the thickness direction. One of the pair of second connection conductor portions on the primary side is connected to the second lower conductor portion on the primary side. The coil component according to any one of claims 3 to 7.

9. The other of the pair of first connection conductor portions on the primary side is connected to the first lower conductor portion of the adjacent first circumferential portion on the primary side. The other of the pair of second connection conductor portions on the primary side is connected to the second lower conductor portion of the adjacent second circumferential portion on the primary side. The coil component according to claim 8.

10. The primary winding further includes a primary connection portion that electrically connects one of the plurality of first circumferential portions on the primary side and one of the plurality of second circumferential portions on the primary side. The coil component according to claim 9.

11. Each of the plurality of first circumferential portions on the secondary side includes a pair of first connection conductor portions each extending from the first upper conductor portion on the secondary side in the thickness direction. One of the pair of first connection conductor portions on the secondary side is connected to the first lower conductor portion on the secondary side. Each of the plurality of second circumferential portions on the secondary side includes a pair of second connection conductor portions each extending from the second upper conductor portion on the secondary side in the thickness direction. One of the pair of second connection conductor portions on the secondary side is connected to the second lower conductor portion on the secondary side. The coil component according to claim 9 or claim 10.

12. The other of the pair of first connection conductor portions on the secondary side is connected to the first lower conductor portion of the adjacent first circumferential portion on the secondary side. The other of the pair of secondary-side second connection conductor parts is connected to the secondary-side second lower conductor part of the adjacent secondary-side second winding part. The coil component according to claim 11.

13. The secondary winding further includes a secondary-side connection part that electrically connects one of the plurality of secondary-side first winding parts and one of the plurality of secondary-side second winding parts. The coil component according to claim 12.

14. Each of the first cylindrical part and the second cylindrical part is an annular shape with the first direction as the circumferential direction when viewed in the thickness direction. The coil component according to any one of claims 2 to 13.

15. The primary-side first upper conductor part, the primary-side first lower conductor part, the secondary-side first upper conductor part, and the secondary-side first lower conductor part each extend from the inner peripheral side to the outer peripheral side of the first cylindrical part when viewed in the thickness direction. The coil component according to claim 14.

16. The primary-side first upper conductor part, the primary-side first lower conductor part, the secondary-side first upper conductor part, and the secondary-side first lower conductor part are each strip-shaped when viewed in the thickness direction. The coil component according to claim 15.

17. The primary-side first upper conductor part and the secondary-side first upper conductor part each incline in one direction of the circumferential direction of the first cylindrical part with respect to the radial direction of the first cylindrical part when viewed in the thickness direction. The primary-side first lower conductor part and the secondary-side first lower conductor part each incline in the other direction of the circumferential direction of the first cylindrical part with respect to the radial direction of the first cylindrical part when viewed in the thickness direction. The coil component according to claim 15 or claim 16.

18. The primary-side second upper conductor part, the primary-side second lower conductor part, the secondary-side second upper conductor part, and the secondary-side second lower conductor part each extend from the inner peripheral edge to the outer peripheral edge of the second cylindrical part when viewed in the thickness direction. The coil component according to any one of claims 14 to 17.

19. The primary-side second upper conductor part, the primary-side second lower conductor part, the secondary-side second upper conductor part, and the secondary-side second lower conductor part are each strip-shaped when viewed in the thickness direction. The coil component according to claim 18.

20. The primary-side second upper conductor part and the secondary-side second upper conductor part each incline in one direction of the circumferential direction of the second cylindrical part with respect to the radial direction of the second cylindrical part when viewed in the thickness direction. The primary-side second lower conductor portion and the secondary-side second lower conductor portion are each inclined, in the thickness direction, to the other in the circumferential direction of the second cylindrical portion with respect to the radial direction of the second cylindrical portion, the coil component according to any one of claims 18 or 19.

21. A coil-embedded substrate incorporating the coil component according to any one of claims 2 to 20, a plurality of wiring layers laminated in the thickness direction, a plurality of insulating layers interposed between the plurality of wiring layers in the thickness direction, and comprising the coil component is constituted by wiring patterns in the plurality of wiring layers, a coil-embedded substrate.

22. The coil component is a transformer, the coil-embedded substrate according to claim 21.

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