Coil component

Abstract

To provide a coil component in which the bonding strength between a coil conductor and an external electrode is improved.SOLUTION: A coil component 1 in an aspect includes a base body 10 having a first surface, a coil conductor provided inside the base body and including a conductive material, and a first external electrode 21 and a second external electrode 22 provided on the first surface of the base body. The second external electrode is disposed apart from the first external electrode in a first direction L extending along the first surface. The coil conductor includes a circulation part extending in a circumferential direction around a coil axis, a first connection part 25b1 connecting one end of the circulation part and the first external electrode, and a second connection part 25b2 connecting the other end of the circulation part and the second external electrode. The first connection part extends along a second direction W that is orthogonal to the first direction when viewed from a direction perpendicular to the first surface. In a cross section obtained by cutting the first connection part along a sectional surface that is orthogonal to the second direction, the size in the first direction is larger than the size in a third direction T that is orthogonal to the first direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The disclosure herein primarily relates to coil components. [Background technology]

[0002] Coil components are installed in various electronic devices. For example, coil components are used to remove noise from power lines or signal lines of circuits. The coil component includes a base made of a magnetic material, a coil conductor provided on the base, a first external electrode connected to one end of the coil conductor, and a second external electrode connected to the other end of the coil conductor.

[0003] In order to reduce the size of the coil component, the first external electrode and the second external electrode may each be attached to only one surface (mounting surface) of the surface of the base. For example, in the inductor described in JP 2018-101732 A (Patent Document 1), external electrodes 13, 13 are attached only to the mounting surface of the base.

[0004] In conventional coil components, the winding portion of the coil conductor and the external electrode attached only to the mounting surface of the base are connected by a conductive connecting portion extending in a direction perpendicular to the mounting surface. For example, in Patent Document 1, the winding portion (winding portion 11a) of the coil conductor and the external electrode are connected by a lead-out portion 11b and a conductor 14 extending in a direction perpendicular to the mounting surface of the base. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-101732 Summary of the Invention [Problem to be solved by the invention]

[0006] In a conventional coil component in which a winding portion and an external electrode are connected by a connection portion perpendicular to the mounting surface of a base, an end face of the connection portion extending in a direction perpendicular to the mounting surface is exposed to the outside of the base from the mounting surface, and the connection portion is connected to the external electrode at this end face. Because the end face of this connection portion is small, approximately the same as the cross-sectional area of ​​the connection portion, in conventional coil components, the bonding strength between the coil conductor and the external electrode may be insufficient.

[0007] When a coil component includes a composite substrate in which metal magnetic particles are bound with a binder made of a resin material, the linear expansion coefficient of the substrate is greater than that of the external electrodes. When a coil component including such a composite substrate is used, if the temperature of the coil component rises due to heat generated by a current flowing through the coil conductor, for example, the substrate expands more than the external electrodes, and the resulting thermal stress makes the substrate more likely to peel off from the external electrodes.

[0008] It is an object of the invention disclosed herein to solve or alleviate at least some of the problems mentioned above.

[0009] A more specific object of the invention disclosed in this specification is to improve the bonding strength between the coil conductor and the external electrode in a coil component.

[0010] One of the specific objects of the invention disclosed in this specification is to prevent the external electrodes from peeling off from the base due to thermal stress caused by thermal expansion of the base.

[0011] Objects of the various inventions disclosed in this specification other than those mentioned above will become clear throughout the entire specification. The inventions described in the claims may solve problems other than those understood from the "problem to be solved by the invention." The various inventions disclosed in this specification may be collectively referred to as the "present invention." [Means for solving the problem]

[0012] A coil component according to one aspect of the present invention includes a base having a first surface, a coil conductor made of a conductive material and disposed inside the base, a first external electrode disposed on the first surface of the base, and a second external electrode disposed on the first surface of the base. The second external electrode is disposed spaced apart from the first external electrode in a first direction extending along the first surface. The coil conductor has a winding portion extending in a circumferential direction around the coil axis, a first connection portion connecting one end of the winding portion to the first external electrode, and a second connection portion connecting the other end of the winding portion to the second external electrode. The first connection portion extends along a second direction orthogonal to the first direction when viewed from a direction perpendicular to the first surface. In a first cross section obtained by cutting the first connection portion along a cut plane orthogonal to the second direction, the dimension in the first direction is greater than the dimension in a third direction orthogonal to the first direction. [Effects of the Invention]

[0013] According to the present invention, in a coil component, the bonding strength between the coil conductor and the external electrode can be improved. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view schematically showing a coil component 1 according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view schematically showing a cross section of the coil device 1 taken along line II. FIG. [Figure 3] FIG. 2 is a side view of the coil device 1. [Figure 4] FIG. 2 is a bottom view of the coil device 1. [Figure 5] 3 is a schematic enlarged cross-sectional view showing an enlarged view of the first external electrode and its vicinity in the cross section shown in FIG. 2. FIG. [Figure 6a] 5 is a schematic enlarged bottom view showing an enlarged view of the vicinity of a first external electrode on the bottom surface of the base body shown in FIG. 4. FIG. [Figure 6b] 5 is a schematic enlarged bottom view showing an enlarged view of the vicinity of a second external electrode on the bottom surface of the base shown in FIG. 4. FIG. [Figure 7a] FIG. 4 is a schematic enlarged bottom view illustrating the dimensions of a first external electrode and a first connecting portion. [Figure 7b] FIG. 10 is a schematic enlarged bottom view for explaining the dimensions of a second external electrode and a second connecting portion. [Figure 8a] 2A to 2C are schematic diagrams illustrating a part of the manufacturing process of the coil device 1. FIG. [Figure 8b] 2A to 2C are schematic diagrams illustrating a part of the manufacturing process of the coil device 1. FIG. [Figure 8c] 2A to 2C are schematic diagrams illustrating a part of the manufacturing process of the coil device 1. FIG. [Figure 8d] 2A to 2C are schematic diagrams illustrating a part of the manufacturing process of the coil device 1. FIG. [Figure 8e] 2A to 2C are schematic diagrams illustrating a part of the manufacturing process of the coil device 1. FIG. [Figure 9] FIG. 10 is a schematic bottom view of a coil device 101 according to another embodiment of the present invention. [Figure 10] FIG. 10 is a schematic bottom view of a coil device 201 according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Various embodiments of the present invention will be described below with reference to the drawings as appropriate. Components common to multiple drawings are designated by the same reference numerals throughout the drawings. Please note that the drawings are not necessarily drawn to scale for ease of explanation. The embodiments of the present invention described below do not limit the invention according to the claims. Elements described in the following embodiments are not necessarily essential to the solution of the invention.

[0016] The present invention relates to a coil component. The present invention can be applied to inductors, transformers, filters, reactors, and various other coil components. The present invention can also be applied to coupled inductors, choke coils, and various other magnetically coupled coil components. Applications of the coil components described in this specification are not limited to those explicitly stated in this specification.

[0017] An overview of a coil component 1 according to one embodiment of the present invention will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is a perspective view that schematically shows the coil component 1. Fig. 2 is a cross-sectional view that schematically shows a cross section of the coil component 1 taken along line II shown in Fig. 1. Fig. 3 is a side view of the coil component 1. Fig. 4 is a bottom view of the coil component 1.

[0018] 1 to 4, the coil device 1 includes an insulating base 10, a coil conductor 25 provided on the base 10, a first external electrode 21 provided on the surface of the base 10, and a second external electrode 22 provided on the surface of the base 10 at a position spaced apart from the first external electrode 21. The coil conductor 25 is provided inside the base 10. For ease of explanation, the coil conductor 25 is drawn through the base 10, the first external electrode 21, and the second external electrode 22 in FIGS. 1 and 4. The coil conductor 25 is drawn through the base 10 in FIG. 3.

[0019] In this specification, the arrangement, dimensions, shape, and other aspects of each component may be described based on the "L axis," "W axis," and "T axis" shown in each drawing. The direction along the L axis may be referred to as the L axis direction, the direction along the W axis may be referred to as the W axis direction, and the direction along the T axis may be referred to as the T axis direction. The L axis, W axis, and T axis are perpendicular to each other.

[0020] The coil component 1 can be mounted on a mounting substrate. The mounting substrate is provided with land portions. The coil component 1 is mounted on the mounting substrate by connecting the first external electrode 21 and the second external electrode 22 to the land portions of the mounting substrate. The mounting substrate on which the coil component 1 is mounted can be installed in various electronic devices such as smartphones, tablets, game consoles, automotive electrical components, and servers.

[0021] The base 10 is made of a magnetic material. The base 10 has a roughly rectangular parallelepiped shape. In one embodiment of the present invention, the base 10 is configured so that its dimension in the L-axis direction (length dimension) is greater than its dimension in the W-axis direction (width dimension) and its dimension in the T-axis direction (height dimension). For example, the length dimension is in the range of 1.0 mm to 6.0 mm, the width dimension is in the range of 0.5 mm to 4.5 mm, and the height dimension is in the range of 0.5 mm to 4.5 mm. The dimensions of the base 10 are not limited to those specifically described in this specification. In this specification, the terms "rectangular parallelepiped" or "rectangular parallelepiped shape" do not necessarily mean "rectangular parallelepiped" in the strict mathematical sense. The dimensions and shape of the base 10 are not limited to those explicitly described in this specification.

[0022] The base 10 has an upper surface 10a, a lower surface 10b, a first end surface 10c, a second end surface 10d, a first side surface 10e, and a second side surface 10f. The outer surface of the base 10 is defined by these six surfaces. The upper surface 10a and the lower surface 10b form the surfaces at both ends of the base 10 in the height direction, the first end surface 10c and the second end surface 10d form the surfaces at both ends of the base 10 in the width direction, and the first side surface 10e and the second side surface 10f form the surfaces at both ends of the base 10 in the length direction.

[0023] In the coil device 1, the first external electrode 21 and the second external electrode 22 are both provided on the lower surface 10b of the base 10. The lower surface 10b extends along the L-axis direction and the W-axis direction. In other words, the lower surface 10b extends along the LW plane. The first external electrode 21 and the second external electrode 22 are arranged on the lower surface 10b of the base 10 so as to be spaced apart from each other in the L-axis direction. In the illustrated embodiment, the first external electrode 21 and the second external electrode 22 are in contact only with the lower surface 10b of the base 10 and are not in contact with any surfaces other than the lower surface 10b. The lower surface 10b of the base 10 may be connected to the first end surface 10c via a curved portion C1. The lower surface 10b of the base 10 may also be connected to the second end surface 10d via a curved portion C2. The first external electrode 21 may extend from the lower surface 10b to the curved portion C1. The second external electrode 22 may extend from the lower surface 10b to the curved portion C2. The coil component 1 is disposed so that the lower surface 10b faces the mounting substrate, and therefore the lower surface 10b is sometimes referred to as the "mounting surface." The lower surface 10b of the base 10 is an example of the "first surface" of the base described in the claims.

[0024] The first external electrode 21 and the second external electrode 22 may have a base electrode layer and a plating layer formed on the surface of the base electrode layer. The plating layer is formed, for example, by electrolytic plating. The base electrode layer is formed, for example, by applying a conductive paste to the surface of the base 10. The conductive paste contains a conductive material with excellent conductivity, such as Cu, Ag, Pd, Ni, or an alloy thereof. The base electrode layer may be formed on the surface of the base 10 by plating, for example. When the base electrode layer is a plating layer, it is formed, for example, by electrolytic plating. Two or more plating layers may be formed on the surface of the base electrode layer. The two or more plating layers may include a Ni plating layer and a Sn plating layer provided on the outer side of the Ni plating layer. The two or more plating layers may further include at least one of an Au plating layer and a Pd plating layer.

[0025] The thickness (dimension in the T-axis direction) of each of the first external electrode 21 and the second external electrode 22 may be 5 to 30 μm. When the first external electrode 21 and the second external electrode 22 have a base electrode layer and a plating layer, the thickness of the base electrode layer may be 3 to 20 μm, and the thickness of the plating layer (when there are two or more plating layers, the total thickness of the two or more plating layers) may be 10 μm or less. The first external electrode 21 may have a uniform thickness. The first external electrode 21 may be formed so that the thickness in the vicinity of the first end face 10 c is greater than the thickness in other regions. The second external electrode 22 may have a uniform thickness. The second external electrode 22 may be formed so that the thickness in the vicinity of the second end face 10 d is greater than the thickness in other regions.

[0026] In one embodiment of the present invention, the substrate 10 is made of a magnetic material. Examples of magnetic materials that can be used for the substrate 10 include ferrite, soft magnetic alloy materials, and mixed magnetic materials that are a mixture of these.

[0027] The ferrite for the substrate 10 may be Ni-Cu-Zn ferrite, Ni-Cu-Zn-Mg ferrite, Cu-Zn ferrite, Ni-Cu ferrite, or any other known ferrite.

[0028] The soft magnetic metal material for the substrate 10 contains at least one metal element selected from Fe, Ni, and Co. Examples of soft magnetic metal materials that can be used for the substrate 10 include: (1) metallic Fe or Ni; (2) alloys such as Fe-Si-Cr, Fe-Si-Al, Fe-Ni, Fe-Co, or Fe-Si-B-Nb-Cu; (3) amorphous Fe-Si-Cr-BC or Fe-Si-Cr-B; and (4) mixtures thereof. The substrate 10 may be composed of a plurality of metallic magnetic particles made of a soft magnetic metal material.

[0029] The metal magnetic particles contained in the substrate 10 have a spherical, elliptical, or modified shape when viewed in cross section. The average particle size of the metal magnetic particles contained in the substrate 10 can be 2 to 10 μm. The average particle size of the metal magnetic particles contained in the substrate 10 can be determined, for example, as follows. First, the substrate 10 is cut or polished along its thickness direction (T-axis direction) to expose a cross section, and an SEM image of the cross section is obtained by photographing the cross section with a scanning electron microscope (SEM) at a magnification of approximately 10,000 to 50,000 times. Next, the circle-equivalent diameter (Heywood diameter) of each metal magnetic particle is determined by image analysis of the SEM image. The average circle-equivalent diameter of each metal magnetic particle in the SEM image can then be determined as the average particle size of the metal magnetic particles.

[0030] Each of the plurality of metal magnetic particles contained in the substrate 10 may be bonded to adjacent metal magnetic particles via an insulating film. The insulating film may contain an oxide of a constituent element of the metal magnetic particle. An insulating oxide film may be formed on the surface of each of the plurality of metal magnetic particles, and adjacent metal magnetic particles may be bonded to each other via this oxide film.

[0031] The base 10 may contain a resin. In the base 10, a plurality of metal magnetic particles may be bound by a resin binder. The binder may be made of, for example, a thermosetting resin with excellent insulating properties. The resin material used as the binder has a lower magnetic permeability than the first magnetic material. Examples of resin materials that can be used for the binder include epoxy resin, polyimide resin, polystyrene (PS) resin, high-density polyethylene (HDPE) resin, polyoxymethylene (POM) resin, polycarbonate (PC) resin, polyvinylidene fluoride (PVDF) resin, phenolic resin, polytetrafluoroethylene (PTFE) resin, polybenzoxazole (PBO) resin, and modified resins thereof.

[0032] When multiple metal magnetic particles are bound by a binder in the base 10, the proportion of the metal magnetic particles in the base 10 is desirably 90 vol% or more. The proportion of the binder in the base may be 3 vol% or less, or may be 2 vol% or less.

[0033] The coil conductor 25 has a winding portion 25a extending in the circumferential direction around the coil axis Ax, a first connection portion 25b1 extending from one end of the winding portion 25a to the first external electrode 21, and a second connection portion 25b2 extending from the other end of the winding portion 25a to the second external electrode 22. The coil conductor 25 may be formed by plastically deforming a strip made of a conductive material. For example, the coil conductor 25 may be formed by winding the strip around a mandrel using a commercially available winding machine. When the coil conductor 25 is formed by plastically deforming a strip, from the viewpoint of ease of processing when winding the strip around the coil axis Ax, the winding portion 25a is wound around the coil axis Ax with the longitudinal direction of the cross section of the strip facing the T-axis direction parallel to the coil axis Ax.

[0034] The coil conductor 25 is made of a material with excellent conductivity, such as Cu, Ag, or Ni. The surface of the coil conductor 25 may be covered with an insulating coating. The insulating coating may be made of a thermosetting resin with excellent insulating properties, such as polyurethane, polyamideimide, or phenol. The insulating coating may be made of an oxide of a metal element contained in the coil conductor 25.

[0035] The winding portion 25a is wound around the coil axis Ax for a plurality of turns. The number of turns of the winding portion 25a may be six turns or less. The number of turns of the winding portion 25a may be four turns or less. The winding portion 25a may be wound around the coil axis Ax for a number of turns other than those explicitly described in this specification. The coil axis Ax is an imaginary axis extending in a direction perpendicular to the lower surface 10b. The coil axis Ax may pass through the geometric center of the lower surface 10b when viewed from below. In the illustrated embodiment, the winding portion 25a is provided in two layers in the T-axis direction.

[0036] As clearly shown in FIG. 3, the first connection portion 25b1 extends from one end of the winding portion 25a to the first external electrode 21 in a direction inclined with respect to the coil axis Ax and the lower surface 10b. In one embodiment, the inclination of the first connection portion 25b1 with respect to the lower surface 10b is set to 1 to 10 degrees. To ensure an appropriate size of the first connection end face 25c1 (described later), the inclination of the first connection portion 25b1 with respect to the lower surface 10b is preferably set to 1 to 5 degrees. The inclination of the first connection portion 25b1 with respect to the lower surface 10b can be expressed as the angle between the upper side A1 of the first connection portion 25b1 and the lower surface 10b. As shown in FIG. 4, the first connection portion 25b1 extends along the W-axis direction when viewed from below.

[0037] In conventional coil components, the winding portion and the external electrode are connected by a connecting conductor extending along the T-axis direction. In contrast, in the coil component 1, the first connecting portion 25b1 extends in a direction inclined with respect to the coil axis Ax and the lower surface 10b. This increases the contact area between the first connecting portion 25b1 and the base 10 compared to conventional connection structures. Therefore, in the illustrated embodiment, the adhesion strength between the first connecting portion 25b1 and the base 10 can be increased compared to conventional connection structures. Furthermore, the first connecting portion 25b1 and the first external electrode 21 are both made of a conductive material (typically a metal or an alloy). Furthermore, as described below, the area of ​​the end face (first connection end face 25c1) of the first connecting portion 25b1 is larger than the area of ​​the end face of a conventional connection portion. Therefore, the first external electrode 21 and the first connecting portion 25b1 are firmly joined. Therefore, by increasing the adhesion strength between the first connecting portion 25b1 and the base 10, the adhesion strength of the first external electrode 21 to the base 10 can be increased. This can prevent the first external electrode 21 from peeling off from the base 10.

[0038] The second connection portion 25b2 extends from the other end of the winding portion 25a to the second external electrode 22 in a direction inclined with respect to the coil axis Ax and the lower surface 10b. In one embodiment, the inclination of the second connection portion 25b2 with respect to the lower surface 10b is set to 1 to 10 degrees. To ensure an appropriate size of the second connection end surface 25c2 (described later), the inclination of the second connection portion 25b2 with respect to the lower surface 10b is desirably set to 1 to 5 degrees. Since the second connection portion 25b extends in a direction inclined with respect to the lower surface 10b, the adhesion strength between the second connection portion 25b2 and the base 10 can be increased for the same reason as the adhesion strength between the first connection portion 25b1 and the base 10 is increased. Furthermore, by increasing the adhesion strength between the second connection portion 25b2 and the base 10, the adhesion strength of the second external electrode 22 to the base 10 can be increased. This makes it possible to prevent the second external electrode 22 from peeling off from the base 10.

[0039] In the coil device 1, the first connection portion 25b1 extends from one end of the winding portion 25a at a slight inclination (for example, about 1 to 10°) with respect to the lower surface 10b of the base 10, and therefore functions as a beam that supports a load applied to the base 10. The second connection portion 25b2 extends from the other end of the winding portion 25a at a slight inclination (for example, about 1 to 10°) with respect to the lower surface 10b of the base 10, and therefore functions as a beam that supports a load applied to the base 10. The first connection portion 25b1 is connected to the first external electrode 21, and therefore can support a load that is applied to the base 10 particularly via the first external electrode 21. The second connection portion 25b2 is connected to the second external electrode 22, and therefore can support a load that is applied to the base 10 particularly via the second external electrode 22. Since the load applied to the base 10 is supported by the first connecting portion 25b1 and the second connecting portion 25b2, even if the proportion of the binder is reduced to 3 vol% or less as described above, the mechanical strength of the base 10 can be maintained at a level that does not cause any practical problems.

[0040] Next, the first connecting portion 25b1 and the second connecting portion 25b2 will be further described with reference to Fig. 5. Fig. 5 is an enlarged cross-sectional view showing the vicinity of the first connecting portion 25b1 in the cross section shown in Fig. 2.

[0041] FIG. 5 shows an enlarged cross-section of first connecting portion 25b1 taken along a plane perpendicular to the W-axis direction. In one embodiment, the cross-section of first connecting portion 25b1 has a rectangular shape. The dimension of the cross-section of first connecting portion 25b1 in the T-axis direction is T1, and the dimension of the cross-section in the L-axis direction is L1. As shown, first connecting portion 25b1 is configured and arranged such that the dimension L1 in the L-axis direction of the cross-section taken along a plane perpendicular to the W-axis direction is greater than the dimension T1 in the T-axis direction of the cross-section. Although FIG. 5 shows a cross-section taken near the center in the W-axis direction, first connecting portion 25b1 may be configured such that the dimension in the L-axis direction is greater than the dimension in the T-axis direction of the cross-section at any position in the W-axis direction.

[0042] The first connection portion 25b1 extends from one end of the winding portion 25a in a direction inclined with respect to the coil axis Ax and the lower surface 10b so that the first connection end face 25c1 is exposed from the lower surface 10b to the outside of the base 10. Because the angle between the extension direction of the first connection portion 25b1 and the lower surface 10b is small, e.g., 10° or less, the first connection end face 25c1 has an elongated shape extending in the W-axis direction in bottom view, as shown in Fig. 4. In conventional coil components, the winding portion and the external electrode are connected by a connection portion extending along the T-axis direction, and therefore the area of ​​the end face of the connecting conductor exposed from the base is equal to the cross-sectional area of ​​the strip that constitutes the coil conductor. In contrast, in the illustrated embodiment of the present invention, the first connection portion 25b1 extends at an angle with respect to the coil axis Ax, and therefore a first area representing the area of ​​the first connection end surface 25c1 exposed from the lower surface 10b is larger than a second area representing the cross-sectional area of ​​the strip that constitutes the coil conductor 25. Therefore, in one aspect of the present invention, the first connection portion 25b1 is connected to the first external electrode 21 at the first connection end surface 25c1, which has an area larger than the cross-section of the strip that constitutes the coil conductor 25. In this way, in one aspect of the present invention, by increasing the contact area between the first connection portion 25b1 and the first external electrode 21, the bonding strength between the first connection portion 25b1 and the first external electrode 21 can be improved.

[0043] The second connection portion 25b2 extends from the other end of the winding portion 25a in a direction inclined with respect to the coil axis Ax and the lower surface 10b so that the second connection end face 25c2 is exposed from the lower surface 10b to the outside of the base 10. Like the first connection end face 25c1, the second connection end face 25c2 has an elongated shape extending in the W-axis direction in bottom view. Like the first connection portion 25b1, the second connection portion 25b2 also extends inclined with respect to the coil axis Ax, and therefore the area of ​​the second connection end face 25c2 exposed from the lower surface 10b is larger than the cross-sectional area of ​​the strip that constitutes the coil conductor 25. Therefore, in one aspect of the present invention, the second connection portion 25b2 is connected to the second external electrode 22 at the second connection end face 25c2, which has an area larger than the cross-section of the strip that constitutes the coil conductor 25. In this way, in one aspect of the present invention, by increasing the contact area between the second connection portion 25b2 and the second external electrode 22, the bonding strength between the second connection portion 25b2 and the second external electrode 22 can be improved.

[0044] As described above, in the winding portion 25a, from the viewpoint of processability, the longitudinal direction of the cross section of the strip faces the T-axis direction parallel to the coil axis Ax. In contrast, in the first connecting portion 25b1, the longitudinal direction of the cross section of the strip faces the L-axis direction perpendicular to the T-axis so that the area of ​​the first connecting end face 25c1 is large. Therefore, in the cross section of the first connecting portion 25b1 perpendicular to the W-axis, the dimension L1 in the L-axis direction is larger than the dimension T1 in the T-axis direction. In this way, in the present invention, the area of ​​the first connecting end face 25c1 can be made larger than in an embodiment in which the longitudinal direction of the cross section of the strip faces the T-axis direction and is exposed from the lower surface 10b. Similarly, in the second connection portion 25b2, in order to maximize the area of ​​the second connection end face 25c2, the longitudinal direction of the cross section of the band is oriented in the L-axis direction perpendicular to the T-axis, and therefore the area of ​​the second connection end face 25c2 can be made larger than in an embodiment in which the longitudinal direction of the cross section of the band is exposed from the lower surface 10b while remaining oriented in the T-axis direction.

[0045] The base 10, which contains a resin binder, is more susceptible to thermal expansion than the first external electrode 21 and the second external electrode 22, which are made of a metal material. Therefore, when the temperature of the coil component 1 rises due to heat generated by a current flowing through the coil conductor 25, the base 10 expands more than the first external electrode 21 and the second external electrode 22, causing shear stress to occur between the lower surface 10b of the base 10 and the first external electrode 21 and the second external electrode 22. In one aspect of the present invention, the first connecting portion 25b1 and the second connecting portion 25b are configured so that the areas of the first connecting end face 25c1 and the second connecting end face 25c2 are large, thereby reducing the contact area between the lower surface 10b of the base 10 and the first external electrode 21 and the contact area between the lower surface 10b of the base 10 and the second external electrode 22. Therefore, in one aspect of the present invention, the shear stress acting between the lower surface 10b of the base 10 and the first external electrode 21 and the second external electrode 22 can be reduced, thereby preventing the base 10 from peeling off from the first external electrode 21 or the second external electrode 22.

[0046] To increase the bonding strength between the first connecting portion 25b1 and the first external electrode 21, the area of ​​the first connecting end surface 25c1 of the first connecting portion 25b1 is preferably at least twice the cross-sectional area of ​​the band. It is even more preferable that the area of ​​the first connecting end surface 25c1 of the first connecting portion 25b1 be at least four times the cross-sectional area of ​​the band. Similarly, to increase the bonding strength between the second connecting portion 25b2 and the second external electrode 22, the area of ​​the second connecting end surface 25c2 of the second connecting portion 25b2 is preferably at least twice the cross-sectional area of ​​the band. It is even more preferable that the area of ​​the second connecting end surface 25c2 of the second connecting portion 25b2 be at least four times the cross-sectional area of ​​the band.

[0047] 6a and 6b, the arrangement of the first connecting end surface 25c1 relative to the first external electrode 21 and the arrangement of the second connecting end surface 25c2 relative to the second external electrode 22 will be further described. Fig. 6a is a schematic enlarged bottom view showing an enlarged view of the vicinity of the first external electrode 21 on the underside 10b of the base 10 shown in Fig. 4, and Fig. 6b is a schematic enlarged bottom view showing an enlarged view of the vicinity of the second external electrode 22 on the underside 10b of the base 10 shown in Fig. 4.

[0048] As shown in FIG. 6a, the first connecting end face 25c1 is disposed near the center of the first external electrode 21. More specifically, the first connecting end face 25c1 extends in the L-axis direction so as to intersect with a first center line CL11 that passes through the center of the first external electrode 21 in the L-axis direction. In other words, the first connecting end face 25c1 extends in the L-axis direction from a position on the positive side of the first center line CL11 in the L-axis direction to a position on the negative side of the L-axis direction. Furthermore, the first connecting end face 25c1 extends in the W-axis direction so as to intersect with a second center line CL12 that passes through the center of the first external electrode 21 in the W-axis direction. In other words, the first connecting end face 25c1 extends in the W-axis direction from a position on the positive side of the second center line CL12 in the W-axis direction to a position on the negative side of the W-axis direction. 6a, the first connecting end surface 25c1 may intersect with both the first center line CL11 and the second center line CL12. The first connecting end surface 25c1 may be disposed at a position overlapping with the geometric center of the first external electrode 21 in a bottom view (i.e., when viewed from the T-axis direction).

[0049] As shown in FIG. 6b, the second connecting end face 25c2 is disposed near the center of the second external electrode 22. The arrangement of the second connecting end face 25c2 with respect to the second external electrode 22 can be similar to the arrangement of the first connecting end face 25c1 with respect to the first external electrode 21. More specifically, the second connecting end face 25c2 extends in the L-axis direction so as to intersect with a third center line CL21 passing through the center of the second external electrode 22 in the L-axis direction. The second connecting end face 25c2 also extends in the W-axis direction so as to intersect with a fourth center line CL22 passing through the center of the second external electrode 22 in the W-axis direction. As shown in FIG. 6b, the second connecting end face 25c2 may intersect with both the third center line CL21 and the fourth center line CL22. The second connecting end face 25c2 may be disposed at a position overlapping with the geometric center of the second external electrode 22 in a bottom view (i.e., when viewed from the T-axis direction).

[0050] By arranging the first connection end face 25c1 of the first connection portion 25b1 near the center of the first external electrode 21, the first connection portion 25b1 embedded in the base 10 allows the base 10 to support the center of the first external electrode 21, thereby further improving the adhesive strength of the first external electrode 21 to the base 10. Similarly, by arranging the second connection end face 25c2 of the second connection portion 25b2 near the center of the second external electrode 22, the second connection portion 25b2 embedded in the base 10 allows the base 10 to support the center of the first external electrode 21, thereby further improving the adhesive strength of the second external electrode 22 to the base 10.

[0051] Furthermore, by arranging the first connection end face 25c1 of the first connection portion 25b1 near the center of the first external electrode 21, the first connection portion 25b1 can block the transmission within the base 10 of impacts applied to the first external electrode 21 from various directions on the LW plane. Similarly, by arranging the second connection end face 25c2 of the second connection portion 25b2 near the center of the second external electrode 22, the second connection portion 25b2 can block the transmission within the base 10 of impacts applied to the second external electrode 22 from various directions on the LW plane. This makes it possible to suppress the transmission of impacts applied from the outside to the base 10 via the first external electrode 21 or the second external electrode 22 to the inside of the base 10.

[0052] Next, the dimensions of the first connecting end face 25c1, the second connecting end face 25c2, the first external electrode 21, and the second external electrode 22 will be further described with further reference to Figures 7a and 7b. Figure 7a is a schematic enlarged bottom view showing an enlarged view of the vicinity of the first external electrode 21 on the underside of the base 10 shown in Figure 4, and Figure 7b is a schematic enlarged bottom view showing an enlarged view of the vicinity of the second external electrode 22 on the underside of the base 10 shown in Figure 4. Figures 7a and 7b differ from Figures 6a and 6b in that symbols indicating dimensions are used.

[0053] As shown in Fig. 7a, the dimension L11 of the first connecting end face 25c1 in the L-axis direction is smaller than the dimension W11 of the first connecting end face 25c1 in the W-axis direction. Furthermore, the dimension L31 of the first external electrode 21 in the L-axis direction is smaller than the dimension W31 of the first external electrode 21 in the W-axis direction. As shown in Fig. 7b, the dimension L21 of the second connecting end face 25c2 in the L-axis direction is smaller than the dimension W21 of the second connecting end face 25c2 in the W-axis direction. Furthermore, the dimension L41 of the second external electrode 22 in the L-axis direction is smaller than the dimension W41 of the second external electrode 22 in the W-axis direction.

[0054] In one embodiment of the present invention, the area of ​​the first connecting end face 25c1 is 5% or more of the area of ​​the first external electrode 21. By making the area of ​​the first connecting end face 25c1 5% or more of the area of ​​the first external electrode 21, the first connecting portion 25b1 and the first external electrode 21 can be firmly joined. The area of ​​the first connecting end face 25c1 may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more of the area of ​​the first external electrode 21. By making the area of ​​the first connecting end face 25c1 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more of the area of ​​the first external electrode 21, the first connecting portion 25b1 and the first external electrode 21 can be even more firmly joined.

[0055] In one embodiment of the present invention, the area of ​​the second connection end face 25c2 is 5% or more of the area of ​​the second external electrode 22. By making the area of ​​the second connection end face 25c2 5% or more of the area of ​​the second external electrode 22, the second connection portion 25b2 and the second external electrode 22 can be firmly joined. The area of ​​the second connection end face 25c2 may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more of the area of ​​the second external electrode 22. By making the area of ​​the second connection end face 25c2 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more of the area of ​​the second external electrode 22, the second connection portion 25b2 and the second external electrode 22 can be even more firmly joined.

[0056] Next, a method for manufacturing the coil device 1 will be described with reference to Figures 8a to 8e. The coil conductor 25 is produced, for example, by plastically deforming a strip made of a conductive material using a winding machine. The winding machine may be a commercially available spindle-type winding machine, a commercially available flyer-type winding machine, or any other known winding machine.

[0057] First, with reference to Figures 8a to 8c, an example of a method for producing a coil conductor 25 from a strip 31 made of a metal material with excellent conductivity will be described. As shown in Figure 8a, the strip 31 is a long member. The strip 31 has, for example, a rectangular cross section.

[0058] The winding machine transports the strip 31 wound around a bobbin from the bobbin to a nozzle using a transport roller, and the nozzle supplies the strip 31 to the vicinity of a core bar, which is the axial core. FIG. 8a shows an example of a core bar 30. FIG. 8a shows a cross section perpendicular to the rotation axis Bx of the core bar 30 (which means the orbital axis of the nozzle when the core bar 30 is fixed and the nozzle rotates; the same applies below). The outer peripheral surface of the core bar 30 has a shape corresponding to the inner peripheral surface of the coil conductor 25. For example, the cross section of the core bar 30 shown in FIG. 8a is oval.

[0059] When a spindle-type winding machine is used, the mandrel 30 is supported by a spindle so as to be rotatable about a rotation axis Bx. A nozzle (not shown) is configured to be movable in three axial directions either in synchronization with the rotation of the mandrel 30 or independently of the rotation of the mandrel 30. When winding the strip 31 around the mandrel 30, the position of the nozzle relative to the mandrel 30 is adjusted, and then the mandrel 30 is rotated relative to the nozzle while applying tension to the strip 31 from the nozzle. This causes the strip 31 to be wound tightly around the mandrel 30, forming a winding portion 25a around the mandrel 30 as shown in FIG. 8b. In the illustrated embodiment, the winding portion 25a is wound in two layers, upper and lower, around the mandrel 30. The lower layer of the winding portion 25a is wound along a plane P1 perpendicular to the rotation axis Bx of the mandrel 30.

[0060] When the winding of the winding portion 25a is completed, each nozzle is positioned at one end and the other end of the winding portion 25a. After the winding of the winding portion 25a is completed, the nozzles are rotated around the longitudinal direction of the band so as to twist the band. At the same time, while applying downward tension from the nozzles to the band 31, each nozzle is moved from one end of the winding portion 25a along the W-axis direction. As a result, the band 31 is twisted so that its longitudinal direction changes from the T-axis direction to the L-axis direction, which is perpendicular to the T-axis direction, and is extended from each end of the winding portion 25a in a direction inclined downward with respect to the plane P1. As a result, as shown in Figures 8c(a) and 8c(b), a portion of the band 31 becomes a first inclined portion 31a extending downward with respect to the plane P1 from one end of the winding portion 25a and a second inclined portion 31b extending downward with respect to the plane P1 from the other end of the winding portion 25a. The magnitude of the tension applied downward from the nozzle to the strip 31 is adjusted so that the inclination of the first inclined portion 31a and the second inclined portion 31b with respect to the plane P1 is 1 to 10 degrees. Both the first inclined portion 31a and the second inclined portion 31b extend in a direction inclined not only with respect to the plane P1 but also with respect to the rotation axis Bx.

[0061] Next, the strip 31 is cut at the respective tips of the first inclined portion 31a and the second inclined portion 31b, thereby separating the workpiece 41 having the circumferential portion 25a wound around the core 30, the first inclined portion 31a, and the second inclined portion 31b. Next, the workpiece 41 is removed from the core 30, and the workpiece 41 removed from the core 30 is placed in a molding die.

[0062] Next, a slurry produced by kneading a plurality of metal magnetic particles and a resin material is poured into a molding die in which a coil conductor 25 is placed, and molding pressure is applied to the slurry in the molding die to produce a molded body 50 with a workpiece 41 disposed therein, as shown in FIG. 8d. There are no particular restrictions on the magnetic material and resin material contained in the slurry, and known magnetic materials and resin materials can be used. Next, the molded body 50 is heated to harden the resin material, thereby obtaining a magnetic substrate with a workpiece 51 disposed therein. In the magnetic substrate, the metal magnetic particles are bonded to each other by the hardened resin.

[0063] The magnetic substrate thus obtained is removed from the molding die, and the lower surface of the magnetic substrate removed from the molding die is subjected to a surface treatment to expose the first inclined portion 31a and the second inclined portion 31b from the lower surface. In the surface treatment, the lower surface of the magnetic substrate is subjected to grinding with a grinding blade, polishing, laser processing, or chemical processing such as acid treatment, thereby removing the lower surface of the magnetic substrate down to the resection plane P2. The resection plane P2 corresponds to the lower surface 10b of the substrate 10. When the lower surface of the magnetic substrate 10 is removed down to the resection plane P2, the portions of the first inclined portion 31a and the second inclined portion 31b below the resection plane P2 are also removed. By performing the surface treatment on the lower surface of the magnetic substrate 10 as described above, the magnetic substrate becomes the substrate 10, and a portion of the first inclined portion 31a is removed to form the first connecting portion 25b1, and a portion of the second inclined portion 31b is removed to form the second connecting portion 25b2. As shown in FIGS. 8e and 4, a first connection end face 25c1 of the first connection portion 25b1 and a first connection end face 25c1 of the second connection portion 25b2 are exposed from the lower surface 10b of the base 10.

[0064] By performing surface treatment on the magnetic base by laser processing to remove the lower surface of the magnetic base down to the resection plane P2, damage to the processed surface (i.e., the lower surface 10b of the base 10) can be reduced compared to cutting or polishing. Furthermore, by performing surface treatment on the magnetic base by laser processing, it is possible to remove dirt and oxides adhering to the first connecting end face 25c1 and the second connecting end face 25c2, thereby increasing the bonding strength between the first connecting portion 25b1 and the first external electrode 21 and the bonding strength between the second connecting portion 25b2 and the second external electrode 22. Furthermore, by performing surface treatment on the magnetic base by laser processing, it is possible to remove metal magnetic particles and resin around the first connecting portion 25b1 and the second connecting portion 25b2, and to cause the tips of the first connecting portion 25b1 and the second connecting portion 25b2 to protrude from the lower surface of the base 10.

[0065] Next, a conductive paste is applied to the surface of the base 10 to form the first external electrode 21 and the second external electrode 22. The first external electrode 21 is formed so as to cover the first connecting end surface 25c1 exposed from the lower surface 10b of the base 10, and the second external electrode 22 is formed so as to cover the second connecting end surface 25c2 exposed from the lower surface 10b of the base 10. The first external electrode 21 and the second external electrode 22 may include a plating layer. This plating layer may be two or more layers. The two plating layers may include a Ni plating layer and a Sn plating layer provided on the outside of the Ni plating layer.

[0066] In this manner, the coil component 1 is produced. The method for producing the coil component 1 is not limited to the above method. The coil component 1 may also be produced, for example, by producing a core made of a magnetic material and winding the strip 31 around the winding core of this core. The strip 31 can be wound around the core by a method similar to the process for winding the strip 31 around the mandrel 30. Furthermore, the base 10 in which the coil conductor 25 is disposed may be produced by a thin-film process.

[0067] Next, a coil device 101 according to another embodiment of the present invention will be described with reference to Fig. 9. Fig. 9 shows a bottom view of the coil device 101. The coil device 101 differs from the coil device 1 in that it includes a first connection portion 125b1 instead of the first connection portion 25b1 and a second connection portion 125b2 instead of the second connection portion 25b2. Fig. 9 shows the end faces of the first connection portion 125b1 and the second connection portion 125b2 exposed from the base 10 through the first external electrode 21 and the second external electrode 22.

[0068] As shown in FIG. 9, the first connecting portion 125b1 is configured so that a J-shaped first connecting end surface 125c1 is exposed from the lower surface 10b of the base 10. The first connecting end surface 125c1 has a first linear region 126 extending along the W-axis direction and a curved region 127 extending from one end of the first linear region 126 in the W-axis direction. The first connecting portion 125b1 extends from the end surface shown in FIG. 9 into the inside of the base 10 along the T-axis direction. Similar to the first connecting portion 25b1, the first connecting portion 125b1 is configured so that the dimension in the L-axis direction of a cross section taken along a plane perpendicular to the W-axis is larger than the dimension in the T-axis direction.

[0069] The second connecting portion 125b2 is configured so that an inverted-J-shaped second connecting end surface 125c2 is exposed from the lower surface 10b of the base 10. Similar to the first connecting end surface 125c1, the second connecting end surface 125c2 also has a linear region extending along the W-axis direction and a curved region extending from one end of the first region in the W-axis direction. Also, similar to the first connecting portion 125b1, the second connecting portion 125b2 is configured so that the dimension in the L-axis direction of a cross section taken along a plane perpendicular to the W-axis is larger than the dimension in the T-axis direction.

[0070] The contact area between the first connecting portion 125b1 and the first external electrode 21 is larger than the contact area between the first connecting portion 25b1 and the first external electrode 21 by the amount of the curved region 127, so the first external electrode 21 is more firmly joined to the first connecting portion 125b1. Similarly, the contact area between the second external electrode 22 and the second connecting portion 125b2 is larger by the amount of the curved region, so the second external electrode 22 is more firmly joined to the second connecting portion 125b2.

[0071] Next, a coil device 201 according to another embodiment of the present invention will be described with reference to Fig. 10. Fig. 10 shows a bottom view of the coil device 201. The coil device 201 differs from the coil device 1 in that it includes a first connection portion 225b1 instead of the first connection portion 25b1 and a second connection portion 225b2 instead of the second connection portion 25b2. Fig. 10 shows the end faces of the first connection portion 225b1 and the second connection portion 225b2 exposed from the base 10 through the first external electrode 21 and the second external electrode 22.

[0072] As shown in FIG. 10 , the first connecting portion 225b1 is configured such that a U-shaped first connecting end surface 225c1 is exposed from the lower surface 10b of the base 10. The first connecting end surface 225c1 has a first linear region 226 extending along the W-axis direction, a curved region 227 extending from one end of the first linear region 226 in the W-axis direction, and a second linear region 228 extending along the W-axis direction. The first linear region 226 is connected to one end of the curved region 227, and the second linear region 228 is connected to the other end of the curved region 227. The first connecting portion 225b1 extends from the first connecting end surface 225c1 shown in FIG. 10 into the inside of the base 10 along the T-axis direction. Similar to the first connecting portion 25b1, the second connecting portion 225b2 is configured such that the dimension in the L-axis direction of a cross section cut along a plane perpendicular to the W-axis is larger than the dimension in the T-axis direction.

[0073] The second connecting portion 225b2 is configured so that a U-shaped second connecting end surface 225c2 is exposed from the lower surface 10b of the base 10. The second connecting end surface 225c2 has a U-shape similar to the first connecting end surface 225c1. Similarly to the first connecting portion 225b1, the second connecting portion 225b2 is configured so that the dimension in the L-axis direction of a cross section taken along a plane perpendicular to the W-axis is larger than the dimension in the T-axis direction.

[0074] The contact area between the first connecting portion 225b1 and the first external electrode 21 is larger than the contact area between the first connecting portion 25b1 and the first external electrode 21 by the amount of the curved region 227 and the second straight region 228, so the first external electrode 21 is more firmly joined to the first connecting portion 225b1. Similarly, the contact area between the second external electrode 22 and the second connecting portion 225b2 is larger by the amount of the curved region and the second straight region, so the second external electrode 22 is more firmly joined to the second connecting portion 225b2.

[0075] The dimensions, materials, and arrangements of each component described in the various embodiments above are not limited to those explicitly described in each embodiment, and each component can be modified to have any dimensions, materials, and arrangements that may fall within the scope of the present invention.

[0076] Components not explicitly described in this specification may be added to each of the above-described embodiments, and some of the components described in each embodiment may be omitted.

[0077] The designations "first," "second," "third," etc. in this specification are used to identify components and do not necessarily limit the number, order, or content thereof. Furthermore, numbers used to identify components are used in different contexts, and numbers used in one context do not necessarily indicate the same configuration in another context. Furthermore, this does not prevent a component identified by a certain number from also serving the function of a component identified by another number.

[0078] This specification also discloses the following techniques. [Appendix 1] a substrate (10) having a first surface (10b); a coil conductor (25) made of a conductive material provided inside the base; a first external electrode (21) provided on the first surface of the base; a second external electrode (22) provided on the first surface of the base body and spaced apart from the first external electrode in a first direction (L) extending along the first surface; Equipped with the coil conductor has a winding portion (25a) extending in a circumferential direction around the coil axis, a first connection portion (25b1) connecting one end of the winding portion to the first external electrode, and a second connection portion (25b2) connecting the other end of the winding portion to the second external electrode, the first connection portion extends along a second direction (W) perpendicular to the first direction when viewed from a direction perpendicular to the first surface, a dimension (L11) in the first direction of a first cross section of the first connection portion cut along a cutting plane perpendicular to the second direction is larger than a dimension (T11) of the first cross section in a third direction (T) perpendicular to the first direction; Coil parts. [Appendix 2] the first connection portion has a first end surface (25c1) exposed from the first surface of the base body, and is connected to the first external electrode at the first end surface; 10. The coil component according to claim 1. [Appendix 3] the coil conductor is made of a strip having a rectangular cross section, a first area representing the area of ​​the first end face is larger than a second area representing the cross-sectional area of ​​the strip; 2. A coil component as described in Appendix 2. [Appendix 4] The first area is at least twice the second area. 4. The coil component according to claim 3. [Appendix 5] the first end surface of the first connection portion extends in the first direction so as to intersect with a first center line (CL1) passing through a center of the first external electrode in the first direction; 5. The coil component according to claim 2, wherein the coil component is a coil element. [Appendix 6] the first end surface of the first connection portion extends in the second direction so as to intersect with a second center line (CL2) passing through a center of the first external electrode in the second direction; 6. The coil component according to claim 2, wherein the coil component is a coil element. [Appendix 7] a dimension (L11) of the first end surface of the first connection portion in the first direction is smaller than a dimension (W11) of the first end surface of the first connection portion in the second direction; 7. The coil component according to claim 2, wherein the coil component is a coil element. [Appendix 8] The dimension (L21) of the first external electrode in the first direction is smaller than the dimension (W21) of the first external electrode in the second direction. 8. The coil component according to claim 7. [Appendix 9] The first end surface has a first linear region extending along the second direction and a curved region extending from one end of the first linear region in the second direction. 9. The coil component according to claim 2, wherein the coil component is a coil element. [Appendix 10] the first end surface further has a second linear region extending along the second direction, The first linear region is connected to one end of the curved region, and the second linear region is connected to the other end of the curved region. 10. The coil component according to claim 9. [Appendix 11] The first connection portion is inclined with respect to the first surface. 11. The coil component according to claim 1. [Appendix 12] the substrate includes a plurality of metal magnetic particles; 12. The coil component according to claim 1. [Appendix 13] The substrate further includes a binder, The plurality of metal magnetic particles are bound by the binder. 13. The coil component according to claim 12. [Appendix 14] the first external electrode and the second external electrode are in contact with only the first surface of the base body; 14. The coil component according to claim 1. [Appendix 15] The coil axis extends in a direction perpendicular to the first surface. 15. The coil component according to any one of claims 1 to 14. [Explanation of symbols]

[0079] 1 Coil parts 10 Base 21 1st external electrode 22 2nd external electrode 25 Coil conductor 25a Circular section 25b1, 125b1, 225b1 First connection part 25b2, 125b2, 225b2 Second connection part

Claims

1. a substrate having a first surface; a coil conductor made of a conductive material provided inside the base; a first external electrode provided on the first surface of the base; a second external electrode provided on the first surface of the base body and spaced apart from the first external electrode in a first direction extending along the first surface; Equipped with the coil conductor has a winding portion extending in a circumferential direction around a coil axis, a first connection portion connecting one end of the winding portion to the first external electrode, and a second connection portion connecting the other end of the winding portion to the second external electrode, the first connection portion extends along a second direction orthogonal to the first direction when viewed in a direction perpendicular to the first surface, a dimension in the first direction of a first cross section of the first connection portion taken along a cutting plane perpendicular to the second direction is larger than a dimension of the first cross section in a third direction perpendicular to the first direction; Coil parts.

2. the first connection portion has a first end surface exposed from the first surface of the base body, and is connected to the first external electrode at the first end surface; The coil component according to claim 1 .

3. the coil conductor is made of a strip having a rectangular cross section, a first area representing an area of ​​the first end surface is larger than a second area representing a cross-sectional area of ​​the strip; The coil component according to claim 2 .

4. The first area is at least twice the second area. The coil component according to claim 3 .

5. the first end surface of the first connection portion extends in the first direction so as to intersect with a first center line passing through a center of the first external electrode in the first direction; The coil component according to claim 2 .

6. the first end surface of the first connection portion extends in the second direction so as to intersect with a second center line passing through a center of the first external electrode in the second direction; The coil component according to claim 2 .

7. a dimension of the first end surface of the first connection portion in the first direction is smaller than a dimension of the first end surface of the first connection portion in the second direction; The coil component according to claim 2 .

8. a dimension of the first external electrode in the first direction is smaller than a dimension of the first external electrode in the second direction; The coil component according to claim 7 .

9. The first end surface has a first linear region extending along the second direction and a curved region extending from one end of the first linear region in the second direction. The coil component according to claim 2 .

10. the first end surface further includes a second linear region extending along the second direction; The first linear region is connected to one end of the curved region, and the second linear region is connected to the other end of the curved region. The coil component according to claim 9 .

11. the first connection portion is inclined with respect to the first surface; The coil component according to claim 1 .

12. the substrate includes a plurality of metal magnetic particles; The coil component according to claim 1 .

13. The substrate further includes a binder, The plurality of metal magnetic particles are bound by the binder. The coil component according to claim 12.

14. the first external electrode and the second external electrode are in contact with only the first surface of the base body; The coil component according to claim 1 .

15. The coil axis extends in a direction perpendicular to the first surface. The coil component according to claim 1 .

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