Coil component

Abstract

The coil component includes a body and a coil disposed within the body. The body includes a first region and a second region in the portion of the body where the coil is disposed. The first region includes a magnetic material. The second region is adjacent to and in contact with the first region and includes a material having a shrinkage rate greater than that of the magnetic material.

Description

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Japanese Patent Application No. 2024-230747, filed on December 26, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a coil component. Background Technology

[0004] Existing coil components include a body and a coil disposed in the body (for example, see Japanese Unexamined Patent Publication No. H8-55726). Summary of the Invention

[0005] One aspect of the present invention is to provide a coil component capable of increasing the peak impedance.

[0006] The inventors of this invention conducted research and investigation on coil components that can increase the peak impedance, and as a result, obtained the following new insights.

[0007] The inductive properties of magnetic materials change due to the stress applied to them. These stresses include, for example, compressive or tensile stress. Inductance tends to decrease with increasing compressive stress, and similarly, inductance tends to decrease with increasing tensile stress. However, when the compressive and tensile stresses are in equilibrium, the inductance properties can be improved. This improvement in inductance properties can also lead to an increase in the peak impedance.

[0008] The inventors of this invention further studied and investigated coil components that can balance the compressive and tensile stresses acting on magnetic materials, and obtained the following new insights.

[0009] The raw body is obtained, for example, by sintering a green body. That is, the raw body is obtained, for example, through a sintering process. During sintering, the green body shrinks. In this case, stress may act on the resulting raw body.

[0010] In one structure, the substrate, in the portion of the substrate in which the coil is disposed, includes: a first region comprising a magnetic material; and a second region adjacent to and in contact with the first region, the second region comprising a material with a shrinkage rate greater than that of the magnetic material. The second region is more shrinkable than the first region. In this structure, the first and second regions are in contact with each other, therefore, as the second region shrinks, compressive stress is applied to the first region from the region near the surface of the substrate into the interior of the substrate. The force generated by this compressive stress is confined within the substrate and converted into a force from the first region to the second region. This force from the first region to the second region acts as a tensile stress on the first region. The above structure enables the compressive stress and tensile stress acting on the first region of the substrate portion in which the coil is disposed to tend to be balanced. Therefore, the above structure can improve the peak impedance.

[0011] Based on new understanding of compressive stress and tensile stress, the inventors have proposed the following solution.

[0012] According to one aspect, a coil component includes a body and a coil disposed within the body. The body includes a first region and a second region in the portion of the body in which the coil is disposed. The first region includes a magnetic material. The second region is adjacent to and in contact with the first region and includes a material with a shrinkage rate greater than that of the magnetic material. Attached Figure Description

[0013] Figure 1 This is a perspective view of the coil component shown in the embodiment;

[0014] Figure 2 An exploded perspective view showing the coil and connection;

[0015] Figure 3 This is a schematic diagram of the cross-sectional structure of the coil component shown in the embodiment;

[0016] Figure 4 This is a schematic diagram of the cross-sectional structure of the base body;

[0017] Figure 5 This is a schematic diagram of the cross-sectional structure of the base body;

[0018] Figure 6 A schematic diagram illustrating the interaction of compressive and tensile stresses; and

[0019] Figure 7 This is a schematic diagram of a coil component shown in a modified example of the embodiment. Detailed Implementation

[0020] In the following description, with reference to the accompanying drawings, the same reference numerals are used for the same parts or similar parts with the same function, and repeated descriptions are omitted.

[0021] The following will refer to Figures 1 to 3The structure of the coil component ED1 shown in the embodiment will be described. Figure 1 This is a perspective view of the coil component shown in the embodiment. Figure 2 An exploded perspective view showing the coil and connection. Figure 3 This is a schematic cross-sectional view of the coil component shown in the embodiment. Figure 3 In the text, the section lines representing the cross-section are omitted.

[0022] like Figures 1 to 3 As shown, the coil component ED1 includes a body 1, a plurality of external electrodes 10, and a coil 30. The plurality of external electrodes 10 includes a pair of external electrodes 10. The plurality of external electrodes 10 are disposed on the body 1. The coil 30 is disposed within the body 1 and is electrically connected to the plurality of external electrodes 10. The coil 30 is arranged such that its coil axis is along a first direction D1. The first direction D1 includes the direction of the coil axis of the coil 30.

[0023] The base body 1 has, for example, a cuboid shape. This cuboid shape may include a cuboid shape with chamfered corners and edges, or a cuboid shape with rounded corners and edges. The base body 1 includes a pair of opposing end faces 1a and side faces connecting the pair of end faces 1a. The side faces include multiple side faces. For example, the base body 1 includes four side faces 1c. The surface of the base body 1 includes the pair of end faces 1a and the four side faces 1c. Each of the pair of end faces 1a and the four side faces 1c has a rectangular shape. For example, the rectangular shape may include a shape with chamfered corners, or a shape with rounded corners.

[0024] The pair of end faces 1a are opposite to each other in the first direction D1. That is, the pair of end faces 1a are opposite to each other in the direction of the coil axis of the coil 30. One pair of side faces 1c are opposite to each other in the second direction D2, and the other pair of side faces 1c are opposite to each other in the third direction D3. The four side faces 1c extend along the first direction D1 to connect the pair of end faces 1a. The first direction D1 intersects the second direction D2 and intersects the third direction D3. The second direction D2 intersects the third direction D3. The first direction D1, the second direction D2, and the third direction D3 are, for example, perpendicular to each other.

[0025] For example, the length of body 1 in the first direction D1 is 0.4 mm to 1.6 mm. For example, the length in the second direction D2 is 0.2 mm to 1.0 mm. For example, the length of body 1 in the third direction D3 is 0.2 mm to 0.8 mm. In body 1, for example, the first direction D1 includes the longitudinal direction.

[0026] The pair of external electrodes 10 are disposed at both ends of the body 1. One external electrode 10 is disposed, for example, on one end face 1a. The other external electrode 10 is disposed, for example, on another end face 1a. The pair of external electrodes 10 are separated from each other in a first direction D1. Each of the pair of external electrodes 10 includes an electrode portion located on a corresponding end face 1a of the pair of end faces 1a, and an electrode portion 10c located on four side faces 1c.

[0027] Each electrode portion 10c is located on four side surfaces 1c. Each electrode portion 10c includes an end edge 10e. One electrode portion 10c extends from one end surface 1a toward another end surface 1a to the end edge 10e on the four side surfaces 1c. Another electrode portion 10c extends from another end surface 1a toward one end surface 1a to the end edge 10e on the four side surfaces 1c. The end edge 10e includes the end edge of the external electrode 10 located on the side surface 1c. That is, the external electrode 10 includes the end edge located on the side surface 1c.

[0028] The external electrode 10 includes a conductive material. The conductive material includes, for example, Ag, Pd, Cu, or Al. The conductive material includes, for example, Ag-Pd alloys, Ag-Cu alloys, Ag-Au alloys, or Ag-Pt alloys. The external electrode 10 may include, for example, a coating. The coating includes, for example, a Ni coating, a Sn coating, a Cu coating, or an Au coating. The coating may have a multilayer structure. For example, the coating may include a Ni coating and a Sn coating formed on the Ni coating. For example, the thickness of the portion of the external electrode 10 located on the end face 1a is 5 μm to 50 μm.

[0029] The coil 30 includes a plurality of coil conductors 31. The coil 30 may include at least one coil conductor 31. The coil conductors 31 are configured to at least partially overlap each other when viewed from a first direction D1. Each coil conductor 31 has a shape in which, for example, a portion of the loop is interrupted. Each coil conductor 31 includes a pair of ends. Each coil conductor 31 extends along a loop path between the pair of ends. Among the plurality of coil conductors 31, adjacent coil conductors 31 are interconnected at their respective ends via through-hole conductors 38. When viewed from the first direction D1, the aforementioned adjacent coil conductors 31 overlap at their corresponding ends. The coil component ED1 includes a pair of connecting portions 33 disposed at both ends of the coil 30. The pair of connecting portions 33 electrically connect the coil 30 to the pair of external electrodes 10. Figure 1 In the diagram, the double-dotted lines schematically represent the outer contours of the coil 30 and the connecting part 33.

[0030] like Figure 2As shown, each of the pair of connection portions 33 includes, for example, a plurality of conductors 33a and a conductor 33b. Among the plurality of conductors 33a, adjacent conductors 33a are connected via a through-hole conductor 36. The through-hole conductor 36 electrically connects adjacent conductors 33a. For example, conductors 33a are not exposed on end face 1a. In a configuration where conductors 33a are not exposed on end face 1a, for example, the conductor 33a farthest from coil 30 among the plurality of conductors 33a is connected to the external electrode 10 via a through-hole conductor 39. The through-hole conductor 39 is, for example, located between the conductor 33a farthest from coil 30 and the external electrode 10, and electrically connects them. For example, the conductor 33a farthest from coil 30 may be exposed on end face 1a. In a configuration where conductors 33a are exposed on end face 1a, the conductors 33a exposed on end face 1a are directly connected to the external electrode 10, and each of the pair of connection portions 33 does not include a through-hole conductor 39. The coil component ED1 may have a structure in which one of a pair of connecting portions 33 includes a through-hole conductor 39, and the other connecting portion 33 does not include the through-hole conductor 39. In this structure, one connecting portion 33 is connected to the external electrode 10 at the through-hole conductor 39, and the other connecting portion 33 is connected to the external electrode 10 at the conductor 33a exposed on the end face 1a.

[0031] Conductor 33b is located between coil 30 and the conductor 33a closest to coil 30 among a plurality of conductors 33a. Conductor 33b electrically connects the plurality of conductors 33a to coil 30. Conductor 33b includes, for example, one end connected to conductor 33a and another end connected to coil 30. One end of conductor 33b is connected to conductor 33a through through-hole conductor 36. The other end of conductor 33b is connected to coil 30 through through-hole conductor 37. Among the plurality of coil conductors 31 included in coil 30, the coil conductor 31 closest to end face 1a is connected to conductor 33b through through-hole conductor 37. Figure 2 The illustrations of multiple conductors 33a and a portion of the through-hole conductor 36 are omitted.

[0032] The coil 30 and the connecting portion 33 include a conductive material. The conductive material includes, for example, Ag, Pd, Au, Cu, or Al. The conductive material includes, for example, Ag-Pd alloys, Ag-Cu alloys, Ag-Au alloys, or Ag-Pt alloys. The coil 30 and the connecting portion 33 include, for example, the same conductive material as the external electrode 10. The coil 30 and the connecting portion 33 may also include a conductive material different from that of the external electrode 10.

[0033] The base body 1 includes a pair of base body portions 3a and 3b, and a base body portion 3c. The pair of base body portions 3a and 3b each include a corresponding end face from a pair of end faces 1a. For example, base body portion 3a includes one end face 1a, and base body portion 3b includes the other end face 1a. Base body portion 3c is located between base body portions 3a and 3b in a first direction D1. For example, a connecting portion 33 is provided in base body portion 3a, another connecting portion 33 is provided in base body portion 3b, and a coil 30 is provided in base body portion 3c. Figure 3 The diagram of the through-hole conductor 36 is omitted in the image.

[0034] For example, when the body portion 3a includes a first body portion, the body portion 3c includes a second body portion. For example, when the body portion 3b includes a first body portion, the body portion 3c includes a second body portion.

[0035] The substrate 1 includes, for example, multiple insulating layers with electrical insulation properties. For example, the substrate 1 includes multiple insulating layers stacked along a first direction D1. Each insulating layer includes, for example, a sintered body of a green sheet containing the following material. The substrate 1 includes a sintered body. The substrate 1 is obtained, for example, by sintering a green substrate comprising multiple stacked green sheets. That is, the substrate 1 is obtained, for example, by a sintering process. In the substrate 1, the multiple insulating layers are integrated with each other to the point that their boundaries are not visually discernible. Each of the multiple insulating layers is, for example, rectangular in shape when viewed from the first direction D1. For example, multiple coil conductors 31 and conductors 33a, 33b are respectively disposed between adjacent insulating layers in the multiple insulating layers.

[0036] The boundaries between the base parts 3a and 3b and the base part 3c can be defined as follows.

[0037] For example, the plane defining the boundary between body portion 3a and body portion 3c is parallel to one end face 1a, and this plane contacts the surface contained in the coil conductor 31 that is closest to and opposite to that end face 1a. For example, the plane defining the boundary between body portion 3b and body portion 3c is parallel to another end face 1a, and this plane contacts the surface contained in the coil conductor 31 that is closest to and opposite to that other end face 1a.

[0038] The body portion 3c includes multiple regions 5a and multiple regions 5b. For example, the body portion 3c includes four regions 5a and four regions 5b. The multiple regions 5a are disposed at different positions along the first direction D1. The multiple regions 5b are disposed at different positions along the first direction D1. The multiple regions 5a and multiple regions 5b are disposed at mutually different positions along the first direction D1. Region 5b is positioned adjacent to and in contact with region 5a. Regions 5a and 5b are adjacent to and in contact with each other along the first direction D1. Regions 5a and 5b are, for example, alternately disposed along the first direction D1. Region 5a is located between adjacent regions 5b among the multiple regions 5b. Region 5b is located between adjacent regions 5a among the multiple regions 5a. Each of regions 5a and 5b includes at least one of the aforementioned insulating layers. For example, when region 5a includes a first region, region 5b includes a second region.

[0039] The four regions 5b are arranged relative to each other along the first direction D1, from the body portion 3a toward the body portion 3b, with intervals L1, L2, and L3. That is, the two regions 5b closer to the body portion 3a relative to the center position CL1 are separated from each other by interval L1. The two regions 5b located approximately at the center are separated from each other by interval L2. The two regions 5b closer to the body portion 3b relative to the center position CL1 are separated from each other by interval L3. For example, the intervals L1, L2, and L3 are substantially the same. The four regions 5b are arranged at substantially equal intervals along the first direction D1. Multiple regions 5b may be arranged at different intervals along the first direction D1.

[0040] The term "basically equal intervals" includes, for example, multiple intervals that are equal to each other, multiple intervals whose differences are within a predetermined range of minor differences, or multiple intervals whose differences are within manufacturing tolerances. For example, multiple regions 5b can be considered to be arranged with basically equal intervals when each of the multiple intervals L1, L2, and L3 is within ±20% of the average value of the multiple intervals L1, L2, and L3.

[0041] For example, the edge 10e of electrode portion 10c is in contact with region 5b. For example, the edge 10e is in contact with the region 5b closest to the body portion 3b among a plurality of regions 5b. For example, a portion of the region 5b closest to the body portion 3b is covered by another electrode portion 10c, while the remainder is exposed from that other electrode portion 10c. For example, the remainder is not covered by another electrode portion 10c. For example, the region 5b closest to the body portion 3a is covered by one electrode portion 10c. For example, the entire region 5b closest to the body portion 3a is covered by one electrode portion 10c. The region 5b closest to the body portion 3a may be in contact with the edge 10e. Two regions 5b located approximately at the center, for example, are not in contact with the edge 10e. Two regions 5b located approximately at the center, for example, are exposed from the electrode portion 10c. Two regions 5b located approximately at the center, for example, are not covered by the electrode portion 10c.

[0042] The insulating layer included in region 5a comprises a first material. That is, region 5a includes a first material. The first material includes, for example, a magnetic material. The magnetic material includes, for example, a ferrite material. The ferrite material included in the first material includes, for example, a Ni-Cu-Zn based ferrite material, a Mg-Cu-Zn based ferrite material, a Ni-Cu-Zn-Mg based ferrite material, a Ni-Cu based ferrite material, or a Ni-Zn based ferrite material.

[0043] The insulating layer contained in region 5b includes a second material. That is, region 5b includes a second material. The second material includes, for example, Ni-Cu-Zn ferrite materials, Mg-Cu-Zn ferrite materials, Ni-Cu-Zn-Mg ferrite materials, Ni-Cu ferrite materials, Cu-Zn ferrite materials, glassy materials, forsterite materials, zinc silicate materials, alumina materials, cordierite materials, soapstone materials, or mullite materials, or a mixture of the above materials.

[0044] The shrinkage rate of the second material is greater than that of the first material. The shrinkage rate of the first material refers to the shrinkage rate of the first material during the sintering process of the base body 1, and the shrinkage rate of the second material refers to the shrinkage rate of the second material during the sintering process of the base body 1. The shrinkage rate of the first material is, for example, 10% to 23%, and the shrinkage rate of the second material is, for example, 12% to 25%.

[0045] The shrinkage rates of the first and second materials can be determined, for example, in the following manner.

[0046] Prepare a sample comprising a first material and a sample comprising a second material. Preparing the sample comprising the first material includes preparing a green sheet comprising the first material and cutting the prepared green sheet to a predetermined size. Preparing the sample comprising the second material includes preparing a green sheet comprising the second material and cutting the prepared green sheet to a predetermined size. The predetermined size is, for example, 1.6 mm × 0.8 mm.

[0047] The dimensional changes of each prepared sample in the longitudinal direction were measured using a thermomechanical analyzer (TMA). The heating conditions of the TMA were set to be the same as those of the sintering conditions of the substrate 1. The shrinkage rate, for example, is a percentage value, obtained by dividing the difference between the dimensions before and after heat treatment by the dimensions before heat treatment.

[0048] The relative permeability and relative permittivity of the second material are both less than those of the first material. Therefore, as long as the second material includes materials whose relative permeability and relative permittivity are both less than those of the first material, the second material can include a magnetic material. The insulating layer disposed in the body portions 3a and 3b includes, for example, the first material.

[0049] The relative permeability of the first material is, for example, 2 to 1500. The relative permeability of the second material contained in region 5b is, for example, 1 to 10. For example, the relative permeability of the second material contained in region 5b is, for example, 1. The relative permittivity of the first material is, for example, 8 to 20. The relative permittivity of the second material contained in region 5b is, for example, 3 to 15.

[0050] For example, the relative permeability and relative permittivity of region 5b are less than those of region 5a, respectively. In other words, the relative permeability of region 5b is less than that of region 5a, and the relative permittivity of region 5b is less than that of region 5a.

[0051] The body portion 3c comprises three parts: part 7a, part 7b, and part 7c. Parts 7a, 7b, and 7c are arranged along a first direction D1, for example, in the order of parts 7a, 7b, and 7c. Part 7b is approximately located at the center of parts 7a, 7b, and 7c. Part 7a is located near the body portion 3a, and part 7c is located near the body portion 3b. For example, parts 7a, 7b, and 7c divide the body portion 3c along the first direction D1 into three parts of substantially equal length.

[0052] Here, "substantially equal in length" means, for example, that the lengths of the three parts are equal to each other, or that the difference between the lengths of the three parts is within a predetermined small range, or that the difference between the lengths of the three parts is within the manufacturing tolerance range. For example, when the lengths of parts 7a, 7b, and 7c in the first direction D1 are each within ±20% of the average value of their lengths in the first direction D1, it can be considered that parts 7a, 7b, and 7c divide the base part 3c into three parts of substantially equal length along the first direction D1.

[0053] Each of portions 7a, 7b, and 7c includes, for example, regions 5a and 5b. For instance, portion 7a includes one region 5a and two regions 5b, portion 7b includes two regions 5a and two regions 5b, and portion 7c includes two regions 5a and one region 5b. Adjacent portions 7a and 7b include a region 5a or 5b that overlaps at the boundary between portions 7a and 7b. Adjacent portions 7b and 7c include a region 5a or 5b that overlaps at the boundary between portions 7b and 7c. In each of the plurality of regions 5b, three insulating layers comprising a second material are continuously stacked on top of each other without any region 5a intervening therebetween.

[0054] like Figure 4 As shown, region 5a includes a surface region SR1 contained on the side surface connecting the pair of end faces 1a. Region 5a includes surface regions SR1 contained in each of a plurality of side faces 1c. Region 5a includes a plurality of surface regions SR1. In the plurality of side faces 1c, the surface regions SR1 contained in adjacent side faces 1c are continuous with each other. Each of the plurality of surface regions SR1 is positioned to extend in a direction opposite to each other in a pair of side faces 1c adjacent to the side face 1c containing the surface region SR1.

[0055] Region 5b includes a surface region SR2 contained on the side surface connecting the pair of end surfaces 1a. Region 5b includes surface regions SR2 contained in each of the plurality of side surfaces 1c. Region 5b includes a plurality of surface regions SR2. In the plurality of side surfaces 1c, the surface regions SR2 contained in adjacent side surfaces 1c are continuous with each other. Each of the plurality of surface regions SR2 is positioned to extend in a direction opposite to each other in a pair of side surfaces 1c adjacent to the side surface 1c containing the surface region SR2.

[0056] Figure 4 A diagram showing the cross-sectional structure of the substrate. Figure 4 Includes a portion of a magnified image of body 1 (regions 5a and 5b). Figure 4 The coil 30 is omitted from the diagram. Figure 4 In this text, the section lines representing cross-sections are omitted. For example, when surface region SR1 includes the first surface region, surface region SR2 includes the second surface region.

[0057] Surface regions SR1 and SR2 are contained on the surface of body 1. In adjacent regions 5a and 5b, surface regions SR1 and SR2 are continuous. For example, in a structure where body 1 includes only a plurality of respective regions 5a and 5b, side surface 1c includes only a plurality of respective surface regions SR1 and SR2.

[0058] Surface region SR2 includes natural surfaces. Surface region SR2 is a natural surface. Surface region SR1 may include natural surfaces. Surface region SR1 can be a natural surface. A natural surface refers to a surface that has not undergone mechanical or chemical treatment. For example, a natural surface is a surface composed of the surfaces of grains grown through sintering.

[0059] Surface region SR2 is more concave than surface region SR1. For example, in a cross-section of the substrate 1 taken along a plane perpendicular to a pair of opposing side surfaces 1c and along the first direction D1, surface region SR2 is more concave than surface region SR1. As mentioned above, the shrinkage rate of the second material is greater than that of the first material. Therefore, in the substrate 1 obtained through the sintering process, region 5b shrinks more than region 5a. Therefore, surface region SR2 is more concave than surface region SR1.

[0060] For example, in the cross-section described above, surface region SR2 is concave. Surface region SR2 includes, for example, a curved surface. Surface region SR2 forms a recess on side surface 1c. The recess formed by surface region SR2 is, for example, groove-shaped. In this case, surface region SR2 constitutes a groove bottom extending in a direction opposite to each other along a pair of side surfaces 1c adjacent to the side surface 1c including surface region SR2. Surface region SR1 can be a substantially flat surface. Surface region SR1 can be concave. Even in a structure where surface region SR1 is concave, surface region SR2 is more concave than surface region SR1.

[0061] As described above, among the plurality of side surfaces 1c, the surface regions SR2 contained in adjacent side surfaces 1c are continuous with each other. Therefore, the recesses formed by the surface regions SR2 contained in adjacent side surfaces 1c are also continuous with each other. Figure 5 As shown, continuous grooves on multiple sides 1c are formed in the body 1 at positions corresponding to region 5b. The surface regions SR2 of adjacent sides 1c contained in the multiple sides 1c can be discontinuous. Figure 5 A diagram illustrating the cross-sectional structure of the substrate. For example, Figure 5 This represents the cross-section when region 5b is cut by a plane parallel to a pair of end faces 1a. Figure 5 The coil 30 is omitted from the diagram. Figure 5 In the text, the section lines representing the cross-section are omitted.

[0062] The recess depth of surface region SR2 is 0.5 μm to 5 μm. For example, the recess depth of surface region SR2 can be 1 μm to 2 μm. The recess depth of surface region SR2 can be defined, for example, by the maximum recess depth value in the aforementioned cross-section. In a structure where surface region SR1 is a substantially flat surface, the recess depth of surface region SR2 can be defined by the maximum distance from the plane including surface region SR1 to surface region SR2 in a direction perpendicular to that plane.

[0063] The width W2 of surface region SR2 is, for example, smaller than the width W1 of region 5b in the substrate 1. In each surface region SR2, for example, the width W2 is smaller than the width W1. The width W2 is defined by the width of region 5b on the surface of the substrate 1. The ratio of width W2 to width W1 is, for example, greater than or equal to 0.6 and less than 1.0. As described above, the shrinkage rate of the second material is greater than that of the first material. Therefore, in the substrate 1 obtained by the sintering process, regions 5a located on both sides of region 5b may shift and move closer to each other on the surface side of the substrate 1 as region 5b shrinks. In this case, the width W2 tends to be smaller than the width W1.

[0064] Widths W1 and W2 can be obtained, for example, as follows.

[0065] Obtain a cross-sectional photograph of the coil component ED1 (body 1). For example, the cross-sectional photograph is a photograph of the coil component ED1 cut along a plane perpendicular to a pair of opposing side surfaces 1c, in the first direction D1. Perform image processing on the obtained cross-sectional photograph using software. Based on the image processing results, identify the boundary of region 5b and calculate the widths W1 and W2 on the cross-sectional photograph.

[0066] As described above, the raw body 1 is obtained, for example, by sintering a green raw body. That is, the raw body 1 is obtained, for example, by a sintering process. During the sintering process, the green raw body shrinks, and stress may be generated on the resulting raw body 1.

[0067] In coil component ED1, when the body 1 includes a region 5a containing magnetic material and a region 5b adjacent to and in contact with region 5a and containing material with a shrinkage rate greater than that of the magnetic material in body portion 3c, region 5b is more contracted than region 5a. In coil component ED1, regions 5a and 5b are in contact with each other. Therefore, as... Figure 6 As shown, due to the contraction of region 5b, compressive stress CS acts on region 5a from the region near the surface of the substrate 1 into the interior of the substrate 1. The force based on this compressive stress CS is confined inside the substrate 1 and transformed into a force pointing from region 5a to region 5b. This force pointing from region 5a to region 5b acts as tensile stress TS on region 5a. The coil component ED1 tends to balance the compressive stress CS and tensile stress TS acting on region 5a in the substrate portion 3c. For example, when the compressive stress CS and tensile stress TS are in equilibrium, a slight compressive stress CS can be applied to region 5a. This slight compressive stress CS can increase the relative permeability in region 5a, thereby improving the inductance characteristics. Figure 6 This is a schematic diagram illustrating the interaction of compressive and tensile stresses.

[0068] When the compressive stress acting on a magnetic material increases, the inductance tends to decrease. Similarly, when the tensile stress acting on a magnetic material increases, the inductance also tends to decrease. However, when the compressive and tensile stresses are in equilibrium, the inductance can be improved. In coil component ED1, the compressive and tensile stresses acting on the magnetic material tend to be in equilibrium; therefore, coil component ED1 can improve the inductance characteristics, thereby increasing the peak impedance.

[0069] In the coil component ED1, region 5a can be located between adjacent regions 5b of a plurality of regions 5b.

[0070] The structure of region 5a, located between adjacent regions 5b, further enhances the balance between compressive stress CS and tensile stress TS acting on region 5a. This structure allows for more stable improvement of inductance characteristics. Therefore, this structure can more reliably enhance the peak impedance.

[0071] In the coil component ED1, each of the plurality of regions 5a and each of the plurality of regions 5b can be alternately arranged along the first direction D1.

[0072] The alternating arrangement of multiple regions 5a and multiple regions 5b along the first direction D1 tends to reduce the spacing between adjacent regions 5b in the body portion 3c. Compared to a structure with a large spacing between adjacent regions 5b, a structure with a small spacing between adjacent regions 5b tends to enhance the compressive stress CS acting on region 5a. Therefore, this alternating arrangement helps to further strengthen the balance between the compressive stress CS and the tensile stress TS acting on region 5a. In this way, the inductance characteristics can be improved more reliably, thereby more stably increasing the peak impedance.

[0073] In this coil component ED1, at least one coil conductor 31 includes a coil conductor 31 disposed within a body portion 3c, which is reliably located at a position through which the magnetic flux generated by the coil conductor 31 passes. That is, the body portion 3c affects the characteristics of the coil component, such as impedance and inductance. The body portion 3c includes regions 5a and 5b, where the relative permeability and relative permittivity of region 5b are lower than those of region 5a, respectively. Because the body portion 3c includes region 5b, the coil component ED1 exhibits impedance peaks in the high-frequency band. By including region 5a in the body portion 3c, the coil component ED1 can suppress the reduction in inductance.

[0074] The coil component ED1 is capable of achieving high impedance in the high-frequency band (e.g., 700MHz to 3GHz).

[0075] In the coil component ED1, among the three parts 7a, 7b and 7c that divide the body part 3c into three parts of substantially equal length along the first direction D1, the part 7b located approximately at the center may include region 5b.

[0076] When portion 7b includes region 5b, region 5b, which can induce impedance peaks in the high-frequency band, is located approximately in the center of portion 7b. Therefore, this structure can generate impedance peaks more stably and reliably in the high-frequency band.

[0077] In the coil component ED1, each of the multiple parts 7a, 7b and 7c may include region 5a and region 5b.

[0078] When each of the multiple parts 7a, 7b, and 7c includes regions 5a and 5b, region 5b, which can induce impedance peaks in the high-frequency band, is disposed in each of the multiple parts 7a, 7b, and 7c. Therefore, this structure can generate impedance peaks in the high-frequency band more stably and reliably.

[0079] In the coil component ED1, the body portion 3c may include a plurality of regions 5b disposed at different positions along the first direction D1.

[0080] When the body portion 3c includes the aforementioned multiple regions 5b, multiple regions 5b capable of generating impedance peaks in the high-frequency band are disposed within the body portion 3c. Therefore, this structure can more reliably generate impedance peaks in the high-frequency band.

[0081] In this coil component ED1, multiple regions 5b can be arranged at substantially equal intervals along the first direction D1.

[0082] When multiple regions 5b are arranged at substantially equal intervals along the first direction D1, the multiple regions 5b that can induce impedance peaks in the high-frequency band are also arranged at substantially equal intervals. Therefore, this structure can more stably and reliably form impedance peaks in the high-frequency band.

[0083] The coil component ED1 may include a plurality of coil conductors 31, which may include coil conductors 31 disposed in region 5b.

[0084] When multiple coil conductors 31 include a coil conductor 31 disposed in region 5b, the coil conductor 31 can be disposed in region 5b. Therefore, the peak impedance in the high-frequency band can be achieved through this coil conductor 31, thereby making the peak impedance occur more reliably in the high-frequency band.

[0085] The coil component ED1 may include external electrodes 10 disposed at both ends of the body 1 along the first direction D1 and electrically connected to the coil 30. The body 1 may include a side surface 1c connecting a pair of end faces 1a. The external electrodes 10 may include electrode portions 10c located on the side surface 1c. The end edge 10e of the electrode portion 10c may be in contact with the region 5b.

[0086] In a structure where the end edge 10e of electrode section 10c contacts region 5b, the parasitic capacitance formed between coil 30 and external electrode 10 can be reduced. Therefore, this structure can generate impedance peaks more stably and reliably in the high-frequency band.

[0087] like Figure 7 As shown, each of the plurality of external electrodes 10 may include an end edge 10e located on the surface region SR2. Figure 7 This is a schematic diagram of a coil component shown in a modified example of the embodiment.

[0088] When each of the plurality of external electrodes 10 includes an end edge 10e located on the surface region SR2, the structure can more reliably define the position of the end edge 10e.

[0089] For example, the external electrode 10 includes a sintered metal layer formed by sintering a conductive paste applied to the surface of the substrate 1. When the conductive paste is applied, it tends to remain in the recess formed in the side surface 1c of the surface region SR2. In this case, the position of the end edge 10e is defined as extending along the surface region SR2.

[0090] It should be understood that not all described implementation methods, advantages, and features must be implemented or possessed simultaneously in a particular embodiment. In fact, the various embodiments described and illustrated in this specification can be adjusted and modified in structure and detail as needed.

[0091] The number of regions 5a and regions 5b is not limited to the number shown. Regions 5b can be arranged symmetrically with respect to the center position CL1 of the body portion 3c. When regions 5b are arranged symmetrically with respect to the center position CL1 of the body portion 3c, impedance peaks can be generated more reliably in the high-frequency band.

Claims

1. A coil component, in, include: Base body; and Coils disposed within the body of the substrate The body includes a first region and a second region in the body portion where the coil is provided. The first region includes a magnetic material, and the second region is adjacent to and in contact with the first region, and includes a material with a shrinkage rate greater than that of the magnetic material.

2. The coil component as claimed in claim 1, wherein, The second region includes multiple second regions disposed at different positions along the coil axis of the coil. The first region is located between adjacent second regions among the plurality of second regions.

3. The coil component as claimed in claim 2, wherein, The first region includes a plurality of first regions disposed at different positions along the coil axis direction of the coil. Each of the plurality of second regions is alternately arranged with each of the plurality of first regions along the coil axis direction of the coil.

4. The coil component as described in any one of claims 1 to 3, wherein, The body includes a pair of end faces facing each other along the coil axis of the coil, and a side surface connecting the pair of end faces. The first region includes a first surface region contained within the side surface. The second region includes a second surface region that is contained within the side surface and is more recessed than the first surface region.

5. The coil component as claimed in claim 4, wherein, The depth of the depression in the second surface region is 0.5 μm to 5 μm.

6. The coil component as claimed in claim 4 or 5, wherein, The second surface region has a width smaller than the width of the second region in the body.

7. The coil component as claimed in any one of claims 4 to 6, wherein, The second surface region contains natural surfaces.

8. The coil component as claimed in any one of claims 4 to 7, wherein, The side includes multiple sides. The second surface region is included in each of the plurality of side surfaces. The recesses in the second surface regions of the plurality of adjacent sides are continuous with each other.

9. The coil component as claimed in any one of claims 4 to 8, wherein, It also includes external electrodes disposed on the substrate and electrically connected to the coil. The external electrode includes an end edge located on the second surface region.

10. The coil component as claimed in any one of claims 1 to 9, wherein, The second region has a relative permeability and a relative permittivity that are respectively smaller than those of the first region.

11. The coil component as claimed in any one of claims 1 to 10, wherein, The magnetic material includes ferrite materials.

12. A coil component, in, include: A basic body, comprising a pair of opposing end faces and side faces connecting the pair of end faces; and Coils disposed within the body of the substrate The pair of end faces are opposite each other along the coil axis direction of the coil. The body includes a first region and a second region that are adjacent to and in contact with each other along the coil axis of the coil. The first region includes a first surface region contained within the side surface. The second region includes a second surface region that is contained within the side surface and is more recessed than the first surface region.

13. The coil component as claimed in claim 12, wherein, The depth of the depression in the second surface region is 0.5 μm to 5 μm.

14. The coil component as claimed in claim 12 or 13, wherein, The second surface region has a width smaller than the width of the second region in the body.

15. The coil component as claimed in any one of claims 12 to 14, wherein, The second surface region contains natural surfaces.

16. The coil component as claimed in any one of claims 12 to 15, wherein, The side includes multiple sides. The second surface region is included in each of the plurality of side surfaces. The recesses in the second surface regions of the plurality of adjacent sides are continuous with each other.

17. The coil component as claimed in any one of claims 12 to 16, wherein, It also includes external electrodes disposed on the substrate and electrically connected to the coil. The external electrode includes an end edge located on the second surface region.

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