JP2021100098A - Inductor - Google Patents

Abstract

To provide an inductor with the improved heat release characteristic.SOLUTION: An inductor includes: a base body 10 including a mount surface 10b facing a circuit board, an upper surface 10a facing the mount surface, and end surfaces connecting the mount surface and the upper surface; a first external electrode 21 and a second external electrode 22 attached to the mount surface of the base body with a space therebetween in a longitudinal direction that is perpendicular to the end surface; and an internal conductor that is provided in the base body, extends linearly from the first external electrode to the second external electrode in a plan view viewed from a thickness direction perpendicular to the mount surface, and having one end exposed from the mount surface and connected to the first external electrode and the other end exposed from the mount surface and connected to the second external electrode. In a front view viewed from a width direction W that is perpendicular to the thickness direction T and the length direction L, a distance T2 between the upper surface 10a and an axial line A of the internal conductor is smaller than a half of an interval T1 between the upper surface 10a and the mount surface 10b.SELECTED DRAWING: Figure 5

Description

The present invention relates to inductors.

As disclosed in Japanese Patent Application Laid-Open No. 10-144526 (Patent Document 1), a magnetic substrate made of a ferrite material, a rectangular parallelepiped-shaped inner conductor provided in the magnetic substrate, and one end and the other end of the inner conductor. Inductors having two external electrodes, each connected to, have been conventionally known. This internal conductor extends linearly from one external electrode to the other external electrode in a plan view.

Japanese Unexamined Patent Publication No. 10-144526

In recent years, as the current of equipment and circuits has been increasing mainly for electrical components, soft magnetic metal materials that are less likely to cause magnetic saturation even when a large current flows have come to be used as the material of the magnetic substrate of the inductor. ing. However, in a magnetic substrate made of a soft magnetic metal material, an eddy current is likely to be generated as compared with a magnetic substrate made of a ferrite material, and a temperature rise is likely to occur due to Joule heat generated by the eddy current.

Further, when a large current flows through the inductor, heat generation from the current path in the inductor increases. Most of the heat generated in the current path of the inductor is dissipated by heat conduction through the land on the printed circuit board to the printed circuit board on which the inductor is mounted. However, when a large current flows through the inductor, the heat generated by the inductor may not be sufficiently dissipated only by heat dissipation by heat conduction through the land to the printed circuit board.

An object of the present invention is to solve or alleviate at least a part of the above-mentioned problems. One of the more specific objects of the present invention is to improve the heat dissipation characteristics of the inductor. Other objects of the present invention will be made clear through the description throughout the specification. The invention disclosed in the present specification may solve a problem that may be described in addition to the "problem for solving the invention".

An inductor according to an embodiment of the present invention is formed on a substrate having a mounting surface facing a circuit board, an upper surface facing the mounting surface, and an end surface connecting the mounting surface and the upper surface, and the mounting surface of the substrate. A first external electrode attached, a second external electrode attached to the mounting surface of the substrate at a distance from the first external electrode in a length direction perpendicular to the end surface, and a second external electrode provided in the substrate. In a plan view viewed from a thickness direction perpendicular to the mounting surface, the first external electrode extends linearly from the first external electrode toward the second external electrode, and one end is exposed from the mounting surface and connected to the first external electrode. The other end is exposed from the mounting surface and is connected to the second external electrode. The shortest distance between the axis of the inner conductor and the upper surface in the front view seen from the width direction perpendicular to the thickness direction and the length direction is more than half of the distance between the upper surface and the mounting surface. Is also small.

In one embodiment of the invention, the substrate is an upper portion that extends parallel to the mounting surface and the upper surface and is located between the intermediate surface and the upper surface by an intermediate surface equidistant from the mounting surface and the upper surface. It is divided into a region and a lower region between the intermediate surface and the mounting surface. In one embodiment, the internal conductor is located between a first portion connected to the first external electrode, a second portion connected to the second external electrode, and between the first portion and the second portion. It has a third portion, which is located in the upper region and is located in the upper region.

In one embodiment of the present invention, in the inner conductor, the distance between the axis and the upper surface is one half of the distance between the upper surface and the mounting surface in a region of 50% or more of the substrate in the length direction. Smaller than

In one embodiment of the present invention, the first external electrode is attached to the substrate only on the mounting surface.

In one embodiment of the present invention, the second external electrode is attached to the substrate only on the mounting surface.

In one embodiment of the present invention, the first electrical conductivity, which is the electrical conductivity of the internal conductor, is higher than the second electrical conductivity, which is the electrical conductivity of the first external electrode.

In one embodiment of the present invention, the substrate is configured so that a heat sink can be provided on the upper surface thereof.

In one embodiment of the invention, the substrate comprises metal magnetic particles.

In one embodiment of the present invention, the inner conductor has a first inner conductor pattern and a second inner conductor pattern arranged in the substrate at a distance from the inner conductor pattern, and the first inner conductor. Each of the pattern and the internal conductor pattern extends linearly from the first external electrode toward the second external electrode in a plan view viewed from a thickness direction perpendicular to the mounting surface, and one end thereof is from the mounting surface. It is exposed and connected to the first external electrode, and the other end is exposed from the mounting surface and connected to the second external electrode.

The inductor according to one embodiment of the present invention is separated from the third external electrode mounted on the mounting surface of the substrate and the third external electrode on the mounting surface of the substrate in a length direction perpendicular to the end surface. And the fourth external electrode provided in the substrate and extending linearly from the third external electrode toward the fourth external electrode in a plan view viewed from a thickness direction perpendicular to the mounting surface. One end is exposed from the mounting surface and connected to the third external electrode, and the other end is exposed from the mounting surface and connected to the fourth external electrode. In the embodiment, the shortest distance between the axis of the other inner conductor and the upper surface is smaller than half of the distance between the upper surface and the mounting surface in the front view from the width direction.

In one embodiment of the present invention, the distance between the inner conductor and the other inner conductor in the width direction is smaller than at least one of the thickness of the inner conductor and the thickness of the other inner conductor.

The inductor according to one embodiment of the present invention includes a third external electrode mounted between the first external electrode and the second electrode on the mounting surface of the substrate, and the first on the mounting surface of the substrate. A fourth external electrode is attached between the external electrode and the second electrode so as to be separated from the third external electrode in a length direction perpendicular to the end surface, and a fourth external electrode provided in the substrate and perpendicular to the mounting surface. In a plan view viewed from a thick direction, the third external electrode extends linearly from the third external electrode toward the fourth external electrode, one end of which is exposed from the mounting surface and is connected to the third external electrode, and the other end is said. It includes another internal conductor exposed from the mounting surface and connected to the fourth external electrode. In the embodiment, the shortest distance between the axis of the other inner conductor and the upper surface is smaller than half of the distance between the upper surface and the mounting surface in the front view from the width direction.

In one embodiment of the present invention, the distance between the inner conductor and the other inner conductor in the thickness direction is smaller than at least one of the width of the inner conductor and the width of the other inner conductor.

In one embodiment of the present invention, the magnetic permeability of the interconductor region between the inner conductor and the other inner conductor of the substrate is lower than the magnetic permeability in the region other than the interconductor region.

One embodiment of the present invention relates to a circuit board including any of the above inductors.

One embodiment of the present invention relates to an electronic device including the above circuit board.

According to the disclosure of the present specification, the heat dissipation characteristics of the inductor can be improved. As a result, it is possible to suppress an increase in the temperature of the inductor when a current is applied to the inductor, and a larger current can be passed through the inductor.

It is a perspective view of the inductor according to one Embodiment of this invention mounted on a circuit board. It is a front view of the inductor of FIG. It is a top view of the inductor of FIG. It is an exploded view of the inductor of FIG. FIG. 5 is a cross-sectional view taken along the line XX of the inductor of FIG. It is sectional drawing of the inductor according to another embodiment of this invention. It is sectional drawing of the inductor according to another embodiment of this invention. It is sectional drawing of the inductor according to another embodiment of this invention. It is sectional drawing of the inductor according to another embodiment of this invention. It is sectional drawing of the inductor according to another embodiment of this invention. It is sectional drawing of the inductor according to another embodiment of this invention. It is sectional drawing of the inductor according to another embodiment of this invention. It is sectional drawing of the inductor according to another embodiment of this invention. It is a perspective view of the inductor according to another embodiment of this invention. It is a front view of the inductor according to another embodiment of this invention. It is a perspective view of the inductor according to another embodiment of this invention. It is a bottom view of the inductor according to another embodiment of this invention. It is a perspective view of the inductor according to another embodiment of this invention. It is a bottom view of the inductor according to another embodiment of this invention. FIG. 8 is a cross-sectional view taken along the line YY of the inductor of FIG.

Hereinafter, various embodiments of the present invention will be described with reference to the drawings as appropriate. The components common to the plurality of drawings are designated by the same reference numerals throughout the plurality of drawings. It should be noted that each drawing is not always drawn to the correct scale for convenience of explanation.

The inductor 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, the outline of the inductor 1 will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of an inductor 1 according to an embodiment of the present invention, FIG. 2 is a front view of the inductor 1, and FIG. 3 is a plan view of the inductor 1. As shown in the drawing, the inductor 1 is separated from the base 10, the internal conductor 25 provided in the base 10, the external electrode 21 provided on the surface of the base 10, and the external electrode 21 on the surface of the base 10. An external electrode 22 provided at a position is provided.

Each figure shows an L-axis, a W-axis, and a T-axis that are orthogonal to each other. In the present specification, the "length" direction, the "width" direction, and the "thickness" direction of the inductor 1 are the "L" direction and the "W" of FIG. 1, respectively, unless otherwise understood in the context. The direction and the "T" direction. According to the method of determining this direction, the external electrode 22 is arranged at a position separated from the external electrode 21 in the length direction (L-axis direction).

The inductor 1 is used, for example, in a large current circuit through which a large current flows. The inductor 1 may be used in a signal circuit or a high frequency circuit. The inductor 1 may be used as a bead inductor for noise suppression.

The inductor 1 is mounted on the circuit board 2. Two lands 3a and 3b are provided on the mounting board of the circuit board 2. The external electrode 21 is arranged so as to face the land 3a when the inductor 1 is mounted on the circuit board 2, and the external electrode 22 is the land 3b of the circuit board 2 when the inductor 1 is mounted on the circuit board 2. It is arranged so that it can face each other. The inductor 1 may be mounted on the circuit board 2 by joining the external electrode 21 and the land 3a and the external electrode 22 and the land 3b with solder, respectively. Various electronic components other than the inductor 1 can be mounted on the circuit board 2. The circuit board 2 can be mounted on various electronic devices. Electronic devices on which the circuit board 2 can be mounted include smartphones, tablets, game consoles, servers, automobile electrical components, and various other electronic devices. The inductor 1 may be an internal component embedded inside the mounting board of the circuit board 2.

The substrate 10 is formed of a magnetic material into a rectangular parallelepiped shape. In one embodiment of the present invention, the substrate 10 has a length dimension (dimension in the L-axis direction) of 0.4 mm to 10 mm, a width dimension (dimension in the W-axis direction) of 0.2 to 10 mm, and a height dimension (T). Axial dimensions) are formed to be 0.2 to 10 mm. The present invention can be widely applied from relatively small inductors to relatively large inductors. The dimensions of the substrate 10 are not limited to the dimensions specifically described herein. In the present specification, the term "rectangular parallelepiped" or "rectangular parallelepiped shape" does not mean only "rectangular parallelepiped" in a mathematically strict sense.

The substrate 10 has a first main surface 10a, a second main 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 substrate 10 is defined by these six surfaces. The first main surface 10a and the second main surface 10b face each other, the first end surface 10c and the second end surface 10d face each other, and the first side surface 10e and the second side surface 10f face each other. Facing each other. Each of the first end surface 10c and the second end surface 10d connects the first main surface 10a and the second main surface 10b, and also connects the first side surface 10e and the second side surface 10f. Since the first main surface 10a is on the upper side of the substrate 10 when the circuit board 2 is used as a reference, the first main surface 10a may be referred to as an "upper surface". Similarly, the second main surface 10b may be referred to as the "lower surface". Since the inductor 1 is arranged so that the second main surface 10b faces the circuit board 2, the second main surface 10b may be referred to as a "mounting surface" or a "mounting surface 10b".
When referring to the vertical direction of the inductor 1, the vertical direction of FIG. 1 is used as a reference. The thickness direction of the inductor 1 or the substrate 10 can be perpendicular to at least one of the upper surface 10a and the mounting surface 10b. The length direction of the inductor 1 or the substrate 10 can be a direction perpendicular to at least one of the first end surface 10c and the second end surface 10d. The width direction of the inductor 1 or the substrate 10 can be a direction perpendicular to at least one of the first side surface 10e and the second side surface 10f. The width direction of the inductor 1 or the substrate 10 may be a direction perpendicular to the thickness direction and the length direction of the inductor 1 or the substrate 10.

In the illustrated embodiment, the external electrode 21 is provided so as to be in contact with the mounting surface 10b, the first end surface 10c, and the upper surface 10a of the substrate 10. The external electrode 22 is provided so as to be in contact with the mounting surface 10b, the second end surface 10d, and the upper surface 10a of the substrate 10. At least one of the external electrode 21 and the external electrode 22 may be provided on the substrate 10 so as to be in contact with only the mounting surface 10b. FIG. 15 shows an inductor 1 in which the external electrodes 21 and 22 are provided so as to be in contact with only the mounting surface 10b. The shapes and arrangements of the external electrodes 21 and 22 are not limited to those expressly described herein.

The substrate 10 is made of a magnetic material. The magnetic material for the substrate 10 may contain a plurality of metallic magnetic particles. The metal magnetic particles contained in the magnetic material for the substrate 10 include, for example, (1) metal particles such as Fe and Ni, (2) Fe-Si-Cr alloy, Fe-Si-Al alloy, Fe-Ni alloy and the like. Crystal alloy particles, (3) amorphous alloy particles such as Fe-Si-Cr-BC alloy, Fe-Si-Cr-B alloy, or (4) mixed particles in which these are mixed. The composition of the metallic magnetic particles contained in the core 10 is not limited to that described above. For example, the metal magnetic particles contained in the core 10 are Co-Nb-Zr alloy, Fe-Zr-Cu-B alloy, Fe-Si-B alloy, Fe-Co-Zr-Cu-B alloy, Ni-Si-. It may be a B alloy or a Fe-AL-Cr alloy. The Fe-based metal magnetic particles contained in the substrate 10 may contain 80 wt% or more of Fe. An insulating film may be formed on each surface of the metal magnetic particles. The insulating film may be an oxide film formed by oxidizing the above metal or alloy. The insulating film provided on each surface of the metal magnetic particles may be, for example, a silicon oxide film coated by the sol-gel method.

In one embodiment, the metallic magnetic particles have an average particle size of 1.5 to 20 μm. The average particle size of the metal magnetic particles contained in the substrate 10 may be smaller than 1.5 μm or larger than 20 μm. The substrate 10 may contain two or more types of metal magnetic particles having different average particle diameters from each other. For example, the metal magnetic particles for a composite magnetic material include a first metal magnetic particle having a first average particle size, and a second metal magnetic particle having a second average particle size smaller than the first average particle size. May include.

The substrate 10 may be formed of a composite magnetic material containing metal magnetic particles and a binder. When the substrate 10 is formed of a composite magnetic material, the binder contained in the composite magnetic material is, for example, a thermosetting resin having excellent insulating properties. Examples of 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, and phenol (Phenolic). ) Resin, polytetrafluoroethylene (PTFE) resin, or polybenzoxazole (PBO) resin can be used. Further, the binder may be an oxide film on the surface of each of the metal magnetic particles, or an oxide different from the oxide film. The binder is preferably an inorganic material having high thermal conductivity. The metal magnetic particles may be bonded to each other by these oxides. For example, it is desirable that the substrate 10 has a binder content of 5 wt% or less, and the balance is metallic magnetic particles. The content ratio of the binder in the substrate 10 is more preferably 3 wt% or less.

The inner conductor 25 is provided so as to electrically connect the outer electrode 21 and the outer electrode 22 in the substrate 10. The inner conductor 25 and the substrate 10 may be in direct contact with each other. The inner conductor 25 may have a plurality of inner conductor patterns, or may have only a single inner conductor pattern. In the illustrated embodiment, the inner conductor 25 has six inner conductor patterns 25a-25f. One end and the other end of the inner conductor pattern 25a are exposed from the mounting surface 10b toward the outside of the substrate 10, and are connected to the external electrode 21 at the one end and the external electrode 22 at the other end. .. The end face of the inner conductor 25 in contact with the outer electrode 21 faces the land 3a when the inductor 1 is mounted on the circuit board 2, and the end face of the inner conductor 25 in contact with the outer electrode 22 attaches the inductor 1 to the circuit board 2. It is provided so as to face the land 3b when mounting. The inner conductors 25b to 25f have the same or similar shape as the inner conductors 25a. The inner conductor patterns 25a to 25f are arranged apart from each other in the substrate 10. As described above, the internal conductors 25a to 25f are arranged in parallel between the external electrode 21 and the external electrode 22 in the substrate 10. Each of the inner conductor patterns 25a to 25f may be connected to an adjacent inner conductor pattern. For example, a part or the whole of the inner conductor pattern 25b may have at least one of the inner conductor pattern 25a and the inner conductor pattern 25c connected in the substrate 10.

As shown in FIG. 3, the inner conductor pattern 25a extends linearly from the outer electrode 21 toward the second outer electrode 22 in a plan view (from the viewpoint seen from the T axis). That is, the internal conductor pattern 25a does not have a portion that is arranged so as to face each other in the substrate 10 when viewed in a plan view. In the present specification, when the inner conductor pattern 25a does not have a portion in the substrate 10 that faces each other in a plan view, the inner conductor pattern 25a extends linearly from the outer electrode 21 toward the outer electrode 22. .. The inner conductor pattern 25a may be arranged on a straight line drawn from the outer electrode 21 toward the second outer electrode 22. Like the inner conductor patterns 25a, the inner conductor patterns 25b to 25f also extend linearly from the outer electrode 21 toward the second outer electrode 22 in a plan view (from the viewpoint seen from the T axis). Since the inner conductor patterns 25a to 25f extend linearly from the outer electrode 21 toward the second outer electrode 22 in the plan view (from the viewpoint seen from the T axis), the inner conductor pattern turns in the plan view. It does not have a region (turn part).

Next, with reference to FIG. 4, the laminated structure of the inductor 1 produced by the lamination process will be described. FIG. 4 shows an exploded view of the inductor 1. In FIG. 4, the external electrodes 21 and 22 are not shown for convenience of explanation. As shown in FIG. 4, the substrate 10 includes magnetic material layers 11a to 11f, a cover layer 12, and a cover layer 13. Each of the magnetic material layers 11a to 11f, the cover layer 12, and the cover layer 13 is made of a magnetic material. The substrate 10 is laminated in the order of the cover layer 12, the magnetic material layers 11a to 11f, and the cover layer 13 from the positive side to the negative side in the W-axis direction. The cover layers 12 and 13 may each have a plurality of magnetic material layers. The inductor 1 may be made by a method other than the lamination process. For example, the inductor 1 may be made by a thin film process or a compression molding process.

Internal conductor patterns 25a to 25f are provided on one surface of the magnetic material layers 11a to 11f, respectively. In the illustrated embodiment, the inner conductor patterns 25a to 25f are provided on the surface of the pair of surfaces intersecting the W-axis direction of the magnetic layers 11a to 11f on the negative side in the W-axis direction. The inner conductor patterns 25a to 25f are formed, for example, by printing a conductive paste made of a metal or alloy having excellent conductivity by a screen printing method. Of the surfaces of the magnetic layers 11a to 11f, the surface on which the internal conductor patterns 25a to 25f are formed is an example of the coil forming surface. As the material of this conductive paste, Ag, Pd, Cu, Al or an alloy thereof can be used. The inner conductor patterns 25a to 25f may be formed by a method other than the screen printing method, for example, a sputtering method, an inkjet method, or a known method other than these. In one embodiment, the internal conductor patterns 25a-25f are formed from a material having a higher electrical conductivity than the external electrode 21 and the external electrode 22. Further, as the internal conductor patterns 25a to 25f, for example, a conductor wire made of a metal or alloy having excellent conductivity, which is made in advance, may be used. The surface of this conductor may or may not be coated with an insulating film. The insulating film covering the conducting wire may be a resin film made of a resin material. When the inner conductor patterns 25a to 25f are conductors, it is desirable that no plating layer is provided on the surface thereof. The Sn component in the plating layer, particularly the plating layer, may be melted by heat when mounted on the substrate. By not providing a plating layer on the surface of the conducting wire (internal conductor patterns 25a to 25f), it is possible to prevent unintentional deformation of the internal conductor patterns 25a to 25f due to heat when the inductor 1 is mounted on the circuit board 2. it can.

Next, the internal conductor pattern 25a will be described with reference to FIG. FIG. 5 is a cross-sectional view taken along line XX of the inductor 1. The XX-ray cross section of the inductor 1 shows a cross section of the substrate 10 cut at a cut surface parallel to the LT plane and passing through the inner conductor pattern 25a. It may be considered that FIG. 5 shows a view through the substrate 10 so that the internal conductor pattern 25a can be seen in the front view from the W-axis direction (that is, from the width direction). The description of the inner conductor pattern 25a also applies to the inner conductor patterns 25b-25f wherever possible in context. That is, in the following, the inner conductor patterns 25a to 25f will be described by taking the inner conductor pattern 25a as an example.

The substrate 10 extends parallel to the upper surface 10a and the mounting surface 10b, and is divided into an upper region and a lower region by an intermediate surface B equidistant from the upper surface 10a and the mounting surface 10b. That is, the substrate 10 is divided by the intermediate surface B into an upper region between the intermediate surface B and the upper surface 10a and a lower region between the intermediate surface B and the mounting surface 10b. As is clear from this definition, at any position included in the upper region, the distance from the top surface 10a is smaller than the distance from the mounting surface 10b, and at any position included in the lower region, the distance from the top surface 10a is. It is larger than the distance from the mounting surface 10b.

As shown, the internal conductor pattern 25a extends from the external electrode 21 to the external electrode 22 along the axis A extending from the external electrode 21 to the external electrode 22. The lower end of the inner conductor pattern 25a is exposed from the mounting surface 10b, and the first portion 25a1 extending from one end in the positive direction of the T axis and the positive direction of the L axis and the lower end thereof are exposed from the mounting surface 10b. It has a second portion 25a2 extending from one end in the positive direction of the T-axis and a negative direction of the L-axis, and a third portion 25a3 connecting the upper end of the first portion 25a1 and the upper end of the second portion 25a2. The lower end of the first portion 25a1 is connected to the external electrode 21, and the lower end of the second portion 25a2 is connected to the external electrode 22. In the illustrated embodiment, the third portion 25a3 extends parallel to the top surface 10a. The first portion 25a1 and the second portion 25a2 are included in the lower region of the substrate 10, and the third portion 25a3 is included in the upper region of the substrate 10. That is, in the X-ray cross section, the portion of the inner conductor pattern 25a above the intermediate surface B is the third portion 25a3, and the portion below the intermediate surface B is the first portion 25a1 and the second portion. Part 25a2.

In the illustrated embodiment, the third portion 25a3 extends over the range of L2 in the L-axis direction (length direction). L2 is larger than half of the L1 dimension of the substrate 10 in the L-axis direction. That is, the inner conductor pattern 25a is arranged in the upper region of the substrate 10 in a region of 50% or more of the length L1 along the mounting surface 10b of the substrate 10 in the XX line cross section. More specifically, the axis A and the virtual line B of the internal conductor pattern 25a intersect at two intersections, and when the distance between these two intersections is L2, L2 is 50% or more of L1. ..

The inner conductor pattern 25a has an inner peripheral surface 25X extending parallel to the axis A from the outer electrode 21 to the outer electrode 22 between the axis A and the mounting surface 10b, and the outer electrode 21 to the outside between the axis A and the upper surface 10a. It has an outer peripheral surface 25Y extending parallel to the axis A to the electrode 22. The axis A of the inner conductor pattern 25a may be defined with reference to the inner peripheral surface 25X. For example, the axis A may be a set of points equidistant from the inner peripheral surface 25X. The axis A may be a set of midpoints of a line segment sandwiched between a point on the inner peripheral surface 25X, a normal at the point, and a point where the normal intersects the outer peripheral surface 25Y. The axis A substantially coincides with the direction in which the current flows in the inner conductor pattern 25a.

In one embodiment, the cross-sectional area of the cross section obtained by cutting the internal conductor pattern 25a along the direction perpendicular to the axis A (internal conductor cross-sectional area) is the mounting surface of the external electrode 21 in contact with the first end surface 10c. It is larger than the cross-sectional area (outer conductor cross-sectional area) cut along the direction parallel to 10b. In one embodiment, the cross-sectional area of the cross section obtained by cutting the internal conductor pattern 25a along the direction perpendicular to the axis A is such that the portion of the external electrode 22 in contact with the second end surface 10d is parallel to the mounting surface 10b. It is larger than the cross-sectional area cut along. When the cross-sectional area along the mounting surface 10b of the external electrode 21 is not constant, the average of the cross-sectional areas of the external electrodes 21 in each of the cross sections passing through the three points arranged at equal intervals in the T-axis direction is taken as the external electrode. It can be a cross-sectional area of 21. The same applies to the cross-sectional area of the external electrode 22.

The inner conductor pattern 25a is arranged at a position separated from the upper surface 10a by the upper margin D1. More specifically, the inner conductor pattern 25a is arranged so that the distance between the upper surface 10a of the substrate 10 and the outer peripheral surface 25Y of the inner conductor pattern 25a is the upper margin D1. In the illustrated embodiment, the first portion 25a1 of the inner conductor pattern 25a is inclined with respect to the first end surface 10c. Therefore, the region between the first portion 25a1 and the first end surface 10c in the cross section of the substrate 10 becomes narrower as it approaches the external electrode 21. Of the regions between the first portion 25a1 and the first end surface 10c, a narrow region whose width is equal to or less than the upper margin D1 is defined as the first strip region SR1. The width between the first portion 25a1 and the first end surface 10c means the width between the outer peripheral surface 25Y and the first end surface 10c in the first portion 25a1. The width of the first portion 25a and the first end surface 10c means, for example, the distance between the outer peripheral surface 25Y and the first end surface 10c along the direction perpendicular to the axis A. Similarly, the region between the third portion 25c and the second end surface 10d becomes narrower as it approaches the external electrode 22. Of the regions between the third portion 25c and the second end surface 10d, a narrow region whose width is equal to or less than the upper margin D1 is defined as the second strip region SR2.

In one embodiment, in the inner conductor pattern 25a, the distance T2 between the axis A and the upper surface 10a of the substrate 10 is smaller than half of the shortest distance between the upper surface 10a and the mounting surface 10b in the XX line cross section. It is configured and arranged so as to be. In the illustrated embodiment, the distance between the upper surface 10a and the mounting surface 10b is equal to the height dimension T1 of the substrate 10. Therefore, in the illustrated example, the relationship of T2 <T1 / 2 holds. In one embodiment, the thickness of the internal conductor pattern 25a in the direction parallel to the LT plane and perpendicular to the axis A is b1. In the present specification, the thickness b1 of the inner conductor pattern means the dimension of the inner conductor pattern 25a in the direction parallel to the LT plane and perpendicular to the axis A. When the first portion 25a1, the second portion 25a2, and the third portion 25a3 have different thicknesses, the thickness of any one of the first portion 25a1, the second portion 25a2, and the third portion 25a3 is used as the inner conductor pattern 25a. The thickness b1 may be set. The thickness b1 of the inner conductor pattern 25a may be the thickness at a predetermined position (for example, the center in the L-axis direction) of the inner conductor pattern 25a, or may be the average value of the thicknesses at a plurality of positions. Good. For example, the average value of the thicknesses at the three positions evenly dispersed in the L-axis direction may be the thickness b1 of the inner conductor pattern 25a.

In the X-ray cross section (that is, in the front view seen from the W axis), the substrate 10 has a first region 10r1 and a first region 10r1 surrounded by the internal conductor pattern 25a and the mounting surface 10b by the internal conductor pattern 25a. It is partitioned into a second region 10r2 other than the above. More specifically, the first region 10r1 has an inner peripheral edge which is a line of intersection between the inner peripheral surface 25X and the XX line cross section, and the mounting surface 10b and the XX line cross section when viewed from the W axis. It is an area surrounded by the bottom edge, which is the line of intersection with. The second region 10r2 is the outer peripheral edge which is the intersection line of the outer peripheral surface 25Y and the XX line cross section and the upper edge which is the intersection line of the upper surface 10a and the XX line cross section in the front view seen from the W axis. It is a region surrounded by the right edge which is the intersection line of the first end surface 10c and the XX line cross section and the left edge which is the intersection line of the second end surface 10d and the XX line cross section. The inner conductor pattern 25a is configured and arranged so that the magnetic flux density of the first region 10r1 and the magnetic flux density of the second region 10r2 are the same or substantially the same. That is, the magnetic flux density of the first region 10r1 and the magnetic flux density of the second region 10r2 are determined to be equal to or substantially equal to each other, whereby the magnetism is concentrated in one of the first region 10r1 and the second region 10r2. I try to prevent saturation. By making the first area S1 of the first region 10r1 and the second area S2 of the second region 10r2 equal or substantially equal, the magnetic flux density of the first region 10r1 and the magnetic flux density of the second region 10r2 are the same or substantially the same. Can be substantially the same.

Of the second region 10r2, the strip regions SR1 and SR2 are narrower than the other regions in the second region 10r2 (for example, the region between the upper surface 10a of the substrate 10 and the second portion 25a2). This is a region in the second region 10r2 where magnetic saturation is particularly likely to occur. Assuming that the areas of the strip regions SR1 and SR2 are S3 and S4, respectively, S3 and S4 are smaller than S1 and S2. Therefore, for the second region 10r2, the magnetic influence of the strip regions SR1 and SR2 is small, and the contribution can be ignored. Therefore, in one embodiment, the area S1 of the first region 10r1 and the adjusted second area (S2-S3-S4) obtained by dividing the area S2 of the second region 10r2 from S3 and S4 are equal to or substantially equal to each other. The internal conductor pattern 25a is configured and arranged so as to be. For example, the internal conductor pattern 25a can be configured and arranged so that the ratio of the adjusted second area ((S2-S3-S4) / S1) to the first area S1 is 0.99 to 0.96. The ratio of the adjusted second area to the first area S1 may be in the range of 0.88 to 0.98, or may be in the range of 0.86 to 1.0. Practically, when the ratio of the adjusted second area ((S2-S3-S4) / S1) to the first area S1 is in the range of 0.86 to 1.0, the magnetic flux density of the first region 10r1 The magnetic flux density of the second region 10r2 is equal to or substantially equal to that of the magnetic flux density.

By comparing the area S1 of the first region 10r1 and the area S2 of the second region 10r2 without considering the areas and shapes of the strip regions SR1 and SR2, the design of the shape and arrangement of the internal conductor pattern 25a becomes simple. In some cases. In this case, the configuration and arrangement of the internal conductor pattern 25a may be determined based on the ratio of S2 to S1. It is possible to design the internal conductor pattern 25a so that the sum of S3 and S4 does not exceed 10% of S2, in which case the ratio of S2 to S1 is in the range 0.95 to 1.1. The inner conductor pattern 25a is configured and arranged.

The shape and arrangement of the inner conductor pattern 25a are not limited to those illustrated in FIG. The inner conductor pattern 25a can take various shapes and arrangements different from the shapes and arrangements exemplified in FIG. A modified example of the inner conductor pattern 25a will be described with reference to FIGS. 6 to 13.

In another embodiment of the present invention as a modification of the inner conductor pattern 25a, the inner conductor pattern 25a may have a curved surface, as shown in FIG. When the outer peripheral surface 25Y has an intersection where straight lines intersect, magnetic flux may be concentrated near the intersection. According to the internal conductor pattern 25a shown in FIG. 6, since there is no intersection where the straight lines intersect, it is possible to prevent the magnetic flux from concentrating in the vicinity of the intersection. As a result, the DC superimposition characteristic of the inductor 1 is further improved.

In another embodiment of the present invention as a modification of the inner conductor pattern 25a, the inner conductor pattern 25a has a cross section of the inner peripheral surface 25X and the outer peripheral surface 25Y seen from the W axis direction (cross section along the LT surface). In, it may be composed only of a curve. For example, as shown in FIG. 7, the curve constituting the inner peripheral surface 25X and the outer peripheral surface 25Y is an elliptical partial elliptical arc whose long axis is parallel to the L axis or whose long axis coincides with the L axis. May be good. In one embodiment, the internal conductor pattern 25a may have a horizontally long shape in a cross-sectional view seen from the W-axis direction. That is, the inner conductor pattern 25a may be configured so that the dimension in the direction along the L-axis direction is larger than the dimension in the direction along the T-axis direction. In this case, the substrate 10 is formed so that the dimension in the direction along the L-axis direction is larger than the dimension in the direction along the T-axis direction. As an example, the dimension (length) in the L-axis direction of the internal conductor pattern 25a can be 10 mm, and the dimension (height) in the T-axis direction can be 7 mm. As shown in FIG. 8, the curve constituting the inner peripheral surface 25X and the outer peripheral surface 25Y may be an elliptical partial elliptical arc whose minor axis is parallel to the L axis or whose minor axis coincides with the L axis. As shown in FIGS. 7 and 8, when the inner conductor pattern 25a does not have a linear portion parallel to the upper surface 10a, the upper surface 10a of the outer peripheral surface 25Y of the inner conductor pattern 25a is the most. The distance between the close position and the upper surface 10a is defined as the upper margin D1. The curves forming the inner peripheral surface 25X and the outer peripheral surface 25Y may be a partial arc or an elliptical partial elliptical arc. By forming the inner peripheral surface 25X and the outer peripheral surface 25Y only with curved lines in the cross-sectional view seen from the W-axis direction, it is possible to prevent the magnetic flux from concentrating on a part of the region in the substrate 10, and as a result, the inductor 1 DC superimposition characteristics are improved. In particular, since the curves forming the inner peripheral surface 25X and the outer peripheral surface 25Y are elliptical partial elliptical arcs and partial arcs, in addition to preventing the concentration of magnetic flux, the DC resistance (Rdc) is lowered while ensuring the inductance value. It becomes possible.

In another embodiment of the present invention as a modification of the inner conductor pattern 25a, as shown in FIGS. 9 and 10, the first portions 25a1 and the first portion 25a1 and the first portion 25a1 of the inner conductor pattern 25a in the cross section viewed from the W axis direction. The two portions 25a2 may extend in a direction parallel to the T axis. As shown in FIG. 9, the inner peripheral surface 25X and the region connecting the first portion 25a1 and the third portion 25a3 and the region connecting the second portion 25a2 and the third portion 25a3 of the inner conductor pattern 25a and Each of the outer peripheral surfaces 25Y may have the shape of a partial arc. The region connecting the first portion 25a1 and the third portion 25a3 of the inner conductor pattern 25a and the connecting region connecting the second portion 25a2 and the third portion 25a3 have a partial arc shape, so that in the vicinity of the connection region. It is possible to suppress the occurrence of magnetic saturation in the substrate 10. When the inner peripheral surface 25X of the connection region has a partial arc shape, the radius of curvature of the partial arc is 1 of the distance L2 between the first portion 25a1 and the second portion 25a2 of the inner conductor pattern 25a on the mounting surface 10b of the substrate 10. It is preferably / 8 or more and / or 1/4 or less. In these embodiments, the side margin D2, which is the distance between the first portion 25a1 and the first end surface 10c of the substrate 10, is smaller than the upper margin D1. In the illustrated embodiment, the distance between the second portion 25a2 and the first end face 10c of the substrate 10 is equal to the side margin D2. The distance between the second portion 25a2 and the second end surface 10d of the substrate 10 may be larger or smaller than the side margin D2. The internal conductor pattern 25a shown in FIG. 9 has a first protruding portion 25a4 projecting from the lower end portion of the first portion 25a1 toward the first end surface 10c, and a second end surface 10d from the lower end portion of the third portion 25a3. It has a second protruding portion 25a5 that protrudes toward the direction. The areas of the strip regions SR1 and SR2 are reduced by the first protrusions 25a4 and the second protrusions 25a5, but the strip regions SR1 and SR2 are magnetically saturated immediately after the current starts to flow in the internal conductor pattern 25a. Even if the area of SR2 is reduced, the effect on the DC superimposition characteristics is small. Therefore, the first protruding portion 25a4 and the second protruding portion 25a5 increase the contact area between the internal conductor pattern 25a and the external electrodes 21 and 22 without substantially adversely affecting the DC superimposition characteristics, and electrically connect the two. You can connect securely. Further, by increasing the contact area between the internal conductor pattern 25a and the external electrodes 21 and 22, the heat in the inductor 1 can be more efficiently dissipated from the external electrodes 21 and 22 via the lands 3a and 3b). it can. As shown in FIG. 10, the internal conductor pattern 25a does not have the first protruding portion 25a4 and the second protruding portion 25a5, and may be configured to be exposed only from the mounting surface 10b. In another embodiment, the side margin D2 may be zero.

In another embodiment of the present invention as a modification of the inner conductor pattern 25a, FIGS. 11 to 13 show a further modification of the inner conductor pattern 25a. In FIGS. 11 to 13, the external electrodes 21 and 22 are omitted for simplification of the illustration. FIG. 11 shows a modified example of the internal conductor pattern 25a shown in FIG. The inner conductor pattern 25a of FIG. 11 is arranged between the inner virtual ellipse C1 and the outer virtual ellipse C2. The virtual ellipse C1 has a minor axis of L1 / 2 length extending in the L-axis direction and a length of T1 / 2 centered on the midpoint of the side corresponding to the mounting surface 10b in the L-axis cross section in the L-axis direction. Has a long axis of. The outer virtual ellipse C2 is concentric with the virtual ellipse C1 and has a minor axis of length L1 extending in the L-axis direction and a major axis of length T1.

FIG. 12 shows a modified example of the internal conductor pattern 25a shown in FIG. The inner conductor pattern 25a of FIG. 12 is arranged between the virtual circle C11 and the virtual circle C12. The virtual circle C11 has a diameter of T1 / 2 extending in the L-axis direction about the midpoint in the L-axis direction of the side corresponding to the mounting surface 10b in the X-ray cross section. The outer virtual circle C12 is concentric with the virtual circle C11 and has a diameter of T1.

FIG. 13 shows a modified example of the internal conductor pattern 25a shown in FIG. The inner conductor pattern 25a of FIG. 13 is arranged between the inner virtual line C21 and the outer virtual line C22. The virtual line C21 is composed of two quadrant arcs C21a having a radius T1 / 2 and a line segment C21b connecting the two quadrant arcs C21a. The virtual line C22 is composed of two quadrant arcs C22a having a radius T1 and a line segment C22b connecting the two quadrant arcs C22a.

According to the embodiment shown in FIGS. 11 to 13, the curves forming the inner peripheral surface 25X and the outer peripheral surface 25Y are elliptical partial elliptical arcs and partial arcs, in addition to preventing the concentration of magnetic flux. It is possible to reduce the direct current resistance (Rdc) while ensuring the inductance value. According to the embodiment of FIG. 13, a region defined by linearly extending line segments C21b and C22b in the third portion 25a3 extends in the vicinity of the upper surface 10a along the upper surface 10a. A larger portion of the inner conductor pattern 25a can be arranged in the vicinity of the upper surface 10a as compared with the 12th embodiment. As a result, according to the embodiment of FIG. 13, the heat dissipation efficiency can be further increased.

FIG. 14 shows an inductor 1 according to another embodiment of the present invention. The inductor 1 shown in FIG. 14 has a heat sink 30 provided on the upper surface 10a of the substrate 10. The heat sink 30 is arranged so as to face the inner conductor 25. The illustrated heat sink 30 has a large number of fins in order to increase the amount of heat radiation. The heat sink 30 is formed of aluminum, copper, nickel, and other materials having high thermal conductivity.

Subsequently, another embodiment of the present invention will be described with reference to FIGS. 16 and 17. FIG. 16 shows a perspective view of the inductor 101 according to another embodiment of the present invention, and FIG. 17 shows a bottom view of the inductor 101 of FIG. The inductor 101 differs from the inductor 1 having one system of internal conductors (that is, the internal conductor 25) in that it has two systems of internal conductors 125A and 125B. The inductor 101 shown in FIGS. 16 and 17 is a coupling type inductor in which two internal conductors are magnetically coupled. The inductor 101 includes four external electrodes 121a, 121b, 122a, 122b and internal conductors 125A, 125B. The inductor 101 may be used as a common mode choke coil or a transformer. The components of the inductor 101 that are common to the inductor 1 are designated by the same or similar reference numerals as those used in the description of the inductor 1 in FIGS. 16 and 17. Hereinafter, among the components of the inductor 101, those different from the components of the inductor 1 will be mainly described.

In the illustrated embodiment, the external electrodes 121a, 121b, 122a, 122b are provided on the bottom surface 10b of the magnetic substrate 10. The external electrode 122a is arranged at a position separated from the external electrode 121a in the length direction (L-axis direction), and the external electrode 122b is arranged at a position separated from the external electrode 121b in the length direction (L-axis direction). Has been done. The four external electrodes 121a, 121b, 122a, 122b are connected to the corresponding lands 103a, 103b, 103c, 103d, respectively. The shapes and arrangements of the external electrodes 121a, 121b, 122a, 122b are not limited to those shown in the drawings.

The inner conductor 125A is configured and arranged so as to electrically connect the outer electrode 121a and the outer electrode 122a, and the inner conductor 125B is configured and arranged so as to electrically connect the outer electrode 121a and the outer electrode 122a. Will be done. The inner conductors 125A and 125B may have a plurality of inner conductor patterns, or may have only a single inner conductor pattern. The shapes of the inner conductor 125A and the inner conductor 125B may be the same as or similar to those of the inner conductor 25. The description of the inner conductor 25 in the present specification also applies to the inner conductor 125A and the inner conductor 125B as much as possible. For example, the inner conductor 125A extends along an axis extending from the outer electrode 121a to the outer electrode 122a, the inner conductor 125B extends along the axis extending from the outer electrode 121b to the outer electrode 122b, and the axis of the inner conductor 125A and the substrate 10 The distance between the upper surface 10a and the distance between the axis of the inner conductor 125B and the upper surface 10a of the substrate 10 is smaller than half of the shortest distance between the upper surface 10a and the mounting surface 10b in the XX line cross section. It may be configured and arranged as such.

In one embodiment, the inner conductor 125A and the inner conductor 125B are arranged so as to face each other in the W-axis direction. In one embodiment, more than half of the inner conductor 125A overlaps with the inner conductor 125B in the front view from the W axis. That is, the area of the region where the inner conductor 125A projected on the LT plane and the inner conductor 125B projected on the LT plane overlap may be 1/2 or more of the area of the inner conductor 125A on the projection plane. ..

The inner conductor 125A and the inner conductor 125B are arranged apart from each other by a distance d1 in the W-axis direction. The distance between the inner conductor 125A and the inner conductor 125B is the position where the straight line and the inner conductor 125A intersect and the position where the straight line and the inner conductor 125B intersect, assuming a straight line extending in a direction parallel to the W axis direction. Means the distance between and. As shown in FIG. 17, the distance d1 between the inner conductor 125A and the inner conductor 125B may be constant or substantially constant in the total length in the L-axis direction. When the distance d1 is almost constant in the total length in the L-axis direction, the difference between the smallest distance and the largest distance d1 at an arbitrary position in the plane of the inner conductor 125B facing the inner conductor 125B is 10%. It means that it is within. The distance d1 can be measured on the cut surface obtained by cutting the inductor 101 along the LW surface. When the inner conductor 125A has a plurality of inner conductor patterns, the distance d1 means the distance between the plurality of inner conductor patterns located at the positive end in the W-axis direction and the inner conductor 125B. To do. Similarly, when the inner conductor 125B has a plurality of inner conductor patterns, the distance d1 is between the plurality of inner conductor patterns located at the negative end in the W-axis direction and the inner conductor 125A. Means distance.

In one embodiment, the inner conductor 125A and the inner conductor 125B are configured and arranged such that the distance d1 is smaller than at least one of the thickness of the inner conductor 125A and the thickness of the inner conductor 125B. The inner conductor 125A and the inner conductor 125B are configured and arranged so that the distance d1 is smaller than at least one half of the thickness of the inner conductor 125A and the thickness of the inner conductor 125B. The thickness of the inner conductor 125A and the thickness of the inner conductor 125B can be defined in the same manner as the thickness b1 of the inner conductor pattern 25a.

The substrate 10 of the inductor 101 has an interconductor region 10R1 between the inner conductor 125A and the inner conductor 125B, and a peripheral region 10R2 excluding the interconductor region 10R1. In one embodiment, the substrate 10 is configured such that the magnetic permeability of the interconductor region 10R1 is lower than the magnetic permeability of the peripheral region 10R2.

Subsequently, another embodiment of the present invention will be described with reference to FIGS. 18 to 20. FIG. 18 shows a perspective view of the inductor 201 according to another embodiment of the present invention, FIG. 19 shows a bottom view of the inductor 201 of FIG. 18, and FIG. 20 shows a YY line cross section of the inductor 201 of FIG. The figure is shown. The inductor 201 shown in FIGS. 18 to 20 is different from the inductor 101 shown in FIGS. 16 to 17 in terms of the shape and arrangement of the external electrode and the internal conductor. Specifically, the inductor 201 includes four external electrodes 221a, 221b, 222a, 222b and internal conductors 225A and 225B. Hereinafter, among the components of the inductor 201, those different from the components of the inductors 1 and 101 will be mainly described.

In the illustrated embodiment, the external electrodes 221a, 221b, 222a, 222b are provided on the bottom surface 10b of the magnetic substrate 10. The external electrode 222a is arranged at a position separated from the external electrode 221a in the length direction (L-axis direction), and the external electrode 222b is arranged at a position separated from the external electrode 221b in the length direction (L-axis direction). Has been done. The external electrode 221a is arranged closer to the first end surface 10c than the external electrode 221b, and the external electrode 222a is arranged closer to the second end surface 10d than the external electrode 222b. The four external electrodes 221a, 221b, 222a, 222b are connected to the corresponding lands 203a, 203b, 203c, 203d, respectively. The shapes and arrangements of the external electrodes 221a, 221b, 222a, and 222b are not limited to those shown in the drawings.

The inner conductor 225A is configured and arranged so as to electrically connect the outer electrode 221a and the outer electrode 222a, and the inner conductor 225B is configured and arranged so as to electrically connect the outer electrode 221a and the outer electrode 222a. Will be done. The inner conductors 225A and 225B may have a plurality of inner conductor patterns, or may have only a single inner conductor pattern. The shapes of the inner conductor 225A and the inner conductor 225B may be the same as or similar to those of the inner conductor 25. The description of the inner conductor 25 in the present specification also applies to the inner conductor 225A and the inner conductor 225B as much as possible. For example, the inner conductor 225A extends along an axis extending from the outer electrode 221a to the outer electrode 222a, and the inner conductor 225B extends along an axis extending from the outer electrode 221b to the outer electrode 222b.

As shown in FIG. 19, the inner conductor 225A and the inner conductor 225B are arranged so as to face each other in the T-axis direction. The dimensions of the inner conductors 225A and 225B in the W-axis direction may be referred to as the widths of the inner conductors 225A and 225B, respectively. In the illustrated embodiment, the widths of the inner conductors 225A and 225B are all W1.

As shown in FIG. 20, when viewed from the front in the W-axis direction, the inner conductor 225B is arranged in a region of the substrate 10 surrounded by the inner conductor 225A and the mounting surface 10b. In the illustrated embodiment, the distance between the axis A1 and the upper surface 10a of the substrate 10 of the inner conductor 225A is smaller than half of the shortest distance between the upper surface 10a and the mounting surface 10b in the X-ray cross section. It is configured and arranged so as to be. In another embodiment, the distance between the axis A2 and the top surface 10a of the substrate 10 of the inner conductor 225B is greater than half the shortest distance between the top surface 10a and the mounting surface 10b in the XX line cross section. It is configured and arranged to be small.

The inner conductor 225A and the inner conductor 225B are arranged apart from each other by a distance d2. The distance d2 between the inner conductor 225A and the inner conductor 225B is the position where the straight line and the inner conductor 225A intersect and the said, assuming a straight line extending in a direction perpendicular to the axis A1 of the inner conductor 225A and parallel to the LT plane. It means the distance between the straight line and the position where the inner conductor 225B intersects. As shown in FIG. 20, the distance d2 between the inner conductor 225A and the inner conductor 225B may be constant or substantially constant in the total length in the L-axis direction. When the distance d2 is almost constant in the total length in the L-axis direction, the difference between the smallest distance and the largest distance d2 at an arbitrary position in the plane of the inner conductor 225B facing the inner conductor 225B is 10%. It means that it is within. The distance d2 can be measured on the cut plane obtained by cutting the inductor 201 along the LT plane.

In one embodiment, the inner conductor 225A and the inner conductor 225B are configured and arranged such that the distance d2 is smaller than at least one of the width of the inner conductor 225A and the width of the inner conductor 225B. The inner conductor 225A and the inner conductor 225B may be configured and arranged so that the distance d2 is smaller than at least one half of the width of the inner conductor 225A and the width of the inner conductor 225B.

The substrate 10 of the inductor 201 has an interconductor region 10R3 between the inner conductor 225A and the inner conductor 225B, and a peripheral region 10R4 excluding the interconductor region 10R3. In one embodiment, the substrate 10 is configured such that the magnetic permeability of the interconductor region 10R3 is lower than the magnetic permeability of the peripheral region 10R4.

The inductor 101 may include three or more internal conductors. The C-PHY developed by the MIPI Alliance stipulates that signals are differentially transmitted using three signal lines per lane. The inductor 101 having three internal conductors can be used as a C-PHY compliant common mode choke coil. The inductor 101 may include a heat sink 30 described with reference to FIG.

In one embodiment, in a plan view of the substrate 10 (from a viewpoint viewed from the T-axis), a surface of the substrate 10 facing the first side surface 10e, a surface of the inner conductor 25 facing the first side surface 10e, and a first end surface 10c. The area of the region 10Re surrounded by the second end surface 10d is the surface facing the second side surface 10f of the substrate 10, the second side surface 10f of the inner conductor 25, the first end surface 10c, and the second. It is equal to or substantially equal to the area of the region 10Rf surrounded by the end face 10d. When the area of the region 10Re is between 0.9 and 1.1 times the area of the region 10Rf, the area of the region 10Re is substantially equal to the area of the region 10Rf.

Subsequently, an exemplary manufacturing method of the inductor 1 according to the embodiment of the present invention will be described. The inductor 1 can be manufactured, for example, by a lamination process. Hereinafter, an example of a method for manufacturing the inductor 1 by the lamination process will be described. For this explanation, FIG. 4 is appropriately referred to.

First, a plurality of unfired magnetic sheet made of a magnetic material is prepared. The unfired magnetic sheet becomes the magnetic layers 11a to 11f and the cover layers 12 and 13 after firing. The unfired magnetic sheet is formed, for example, from a composite magnetic material containing a binder and a plurality of metal magnetic particles. Next, by printing a conductive paste on each surface of the unfired magnetic sheet, an unfired conductor pattern that becomes an internal conductor pattern 25a to 25f after firing is formed.

Next, the unfired magnetic sheet on which the unfired conductor pattern is formed is laminated to obtain an intermediate laminate. A plurality of unfired magnetic sheets to be the cover layer 12 are laminated on one end in the laminating direction of the intermediate laminate, and a plurality of unfired magnetic sheets to be the cover layer 13 are laminated on the other end to form an unfired laminate. obtain.

Next, the unfired chip laminate is obtained by individualizing the unfired laminate using a cutting machine such as a dicing machine or a laser processing machine. Next, the unfired chip laminate is degreased and the degreased unfired chip laminate is fired to obtain a fired chip laminate. Next, the fired chip laminate is subjected to a polishing process such as barrel polishing.

Next, the external electrode 21 and the external electrode 22 are formed on the surface of the chip laminate. The external electrode 21 and the external electrode 22 are formed, for example, by applying a conductive paste to the surface corresponding to the mounting surface 10b of the chip laminate to form a base electrode, and forming a plating layer on the surface of the base electrode. Will be done. The plating layer has, for example, a two-layer structure consisting of a nickel plating layer containing nickel and a tin plating layer containing tin. If necessary, at least one of a solder barrier layer and a solder wet layer may be formed on the external electrode 21 and the external electrode 22. From the above, the inductor 1 is obtained.

Subsequently, another exemplary manufacturing method of the inductor 1 according to the embodiment of the present invention will be described. As described below, the inductor 1 can be manufactured by a pressure molding process. Hereinafter, an example of a method for manufacturing the inductor 1 by the pressure molding process will be described. In the pressure molding process described below, the internal conductor patterns 25a to 25f formed by bending the conducting wire are embedded in the substrate 10.

In this pressure molding process, first, a conductor made of metal is bent to form each of the internal conductor patterns 25a to 25f. The inner conductor patterns 25a to 25f may be connected to each other. For example, an internal conductor unit in which adjacent conductor patterns among the internal conductor patterns 25a to 25f are connected to each other may be created by bending one conductor. The extension conductor unit has a conductor pattern portion corresponding to the internal conductor patterns 25a to 25f and a connecting portion for connecting the ends of adjacent conductor pattern portions. This connection may be removed in a later step. When the connection is removed from the extension conductor unit, the extension conductor unit is separated into separate internal conductor patterns 25a to 25f. The conductor may be covered with an insulating film. The plating layer is provided only on the external electrode connecting portion connected to the external electrodes 21 and 22 of the conducting wire, and the plating layer may not be provided on the portion other than the external electrode connecting portion of the conducting wire. This makes it possible to prevent the plating layer (particularly the Sn component in the plating layer) from melting due to heat when the substrate is mounted.

Next, the inner conductor patterns 25a to 25f are individually arranged, or the inner conductor unit in which the adjacent conductor patterns of the inner conductor patterns 25a to 25f are connected to each other is arranged in the molding die. Next, a slurry of a resin material to be a binder and a composite magnetic material obtained by kneading a plurality of metal magnetic particles is poured into a molding die in which internal conductor patterns 25a to 25f are installed, and molding pressure is applied. , A molded body containing the internal conductor patterns 25a to 25f inside can be obtained. The substrate 10 is obtained by sintering or heating the molded body to cure the resin material in the molded body. The heating temperature can be, for example, 200 ° C.

When the inner conductor unit is used, the obtained substrate 10 is polished to remove the connecting portion from the inner conductor unit, and the inner conductor unit is separated into individual inner conductor patterns 25a to 25f.

Next, the external electrode 21 and the external electrode 22 are formed on the surface of the substrate 10. The external electrode 21 and the external electrode 22 are formed, for example, by applying a conductive paste to the mounting surface 10b of the substrate 10 to form a base electrode, and forming a plating layer on the surface of the base electrode. The plating layer has, for example, a two-layer structure consisting of a nickel plating layer containing nickel and a tin plating layer containing tin. If necessary, at least one of a solder barrier layer and a solder wet layer may be formed on the external electrode 21 and the external electrode 22. As described above, the inductor 1 is obtained by the pressure molding process.

Some of the steps included in the above manufacturing method can be omitted as appropriate. In the method of manufacturing the inductor 1, steps not explicitly described herein can be performed as needed. A part of each step included in the above-mentioned method for manufacturing the inductor 1 can be executed by changing the order at any time as long as it does not deviate from the gist of the present invention. If possible, some of the steps included in the above-mentioned method for manufacturing the inductor 1 can be performed simultaneously or in parallel. The inductors 101 and 201 can also be manufactured in the same manner as the inductor 1.

Next, the action and effect according to the above embodiment will be described. According to the inductors 1, 101, and 201 according to the above embodiment, the distance T2 between the axis A of the inner conductor 25 (for example, the inner conductor pattern 25a) and the upper surface 10a is the distance T2 between the upper surface 10a and the mounting surface 10b in the front view. Since it is smaller than half of the interval, Joule heat generated in the inner conductor 25 can be dissipated more efficiently from the upper surface 10a of the substrate 10. Most of the Joule heat generated in the inner conductor 25 is transferred from the inner conductor 25 to another member constituting the circuit board 2 via the lands 3a and 3b by heat conduction, but heat dissipation by this heat conduction alone is sufficient. It may not be possible to dissipate all the Joule heat generated by the inner conductor 25. Therefore, the inner conductor 25 is generated by arranging the inner conductor 25 so that the distance T2 between the axis A of the inner conductor 25 and the upper surface 10a is smaller than half of the distance between the upper surface 10a and the mounting surface 10b. The Joule heat generated can be efficiently released into the atmosphere from the upper surface 10a of the substrate 10. When the inner conductor 25 is formed of a conductor, the conductor may not be covered with an insulating film. The insulating film usually has a lower thermal conductivity than the substrate 10. Therefore, by making the inner conductor 25 directly in contact with the base 10 without covering it with an insulating film, the heat conduction between the inner conductor 25 and the base 10 can be improved, and the Joule generated in the inner conductor 25 can be improved. Heat can be more efficiently released into the atmosphere from the upper surface 10a of the substrate 10. As described above, according to the above embodiment, the heat dissipation characteristics of the inductors 1, 101 and 201 can be improved.

According to the above embodiment, the inner conductor 25 has an axis A of the inner conductor 25 and an upper surface 10a of the base 10 in a region L2 of 50% or more of the length L1 of the base 10 in the length direction (L-axis direction). The distance between the two is smaller than half of the distance between the upper surface 10a and the mounting surface 10b. As a result, the inner conductor 25 and the upper surface 10a can be brought close to each other in a region of 50% or more in the length direction of the substrate 10, so that Joule heat generated in the inner conductor 25 can be discharged more efficiently from the upper surface 10a. Can be done.

According to the above embodiment, the inner conductor pattern 25a is composed of only curved lines in a cross section of the inner peripheral surface 25X and the outer peripheral surface 25Y when viewed from the W axis direction. By forming the inner peripheral surface 25X and the outer peripheral surface 25Y only with curved lines in the cross-sectional view seen from the W-axis direction, it is possible to prevent the magnetic flux from concentrating on a part of the region in the substrate 10, and as a result, the inductor 1, The DC superimposition characteristics of 101 and 201 are improved. In particular, since the curves forming the inner peripheral surface 25X and the outer peripheral surface 25Y are elliptical partial elliptical arcs and partial arcs, in addition to preventing the concentration of magnetic flux, the DC resistance (Rdc) is lowered while ensuring the inductance value. It becomes possible.

According to one embodiment, the internal conductor pattern 25 has a horizontally long shape in a cross-sectional view seen from the W-axis direction, and the length of the substrate 10 in the L direction is larger than the height in the T direction. For example, the curve constituting the inner peripheral surface 25X and the outer peripheral surface 25Y is an elliptical partial elliptical arc whose long axis is parallel to the L axis or whose long axis coincides with the L axis. With such a form, Joule heat generated in the inner conductor 25 can be discharged more efficiently from the upper surface 10a.

According to one embodiment, the curves forming the inner peripheral surface 25X and the outer peripheral surface 25Y may be a partial arc or an elliptical partial elliptical arc. A portion that is neither a partial arc nor a partial elliptical arc of an ellipse may be a straight line. By having curved portions on the inner peripheral surface 25X and the outer peripheral surface 25Y in the cross-sectional view seen from the W-axis direction, it is possible to prevent the magnetic flux from concentrating in a part of the region in the substrate 10, and as a result, the direct current of the inductor 1 Superimposition characteristics are improved. In particular, since the curves forming the inner peripheral surface 25X and the outer peripheral surface 25Y are elliptical partial elliptical arcs and partial arcs, in addition to preventing the concentration of magnetic flux, the DC resistance (Rdc) is lowered while ensuring the inductance value. It becomes possible.

According to the above embodiment, the heat sink 30 provided on the upper surface 10a of the substrate 10 can more efficiently discharge heat from the upper surface 10a. Further, since the inductors 1, 101 and 201 are configured so that the heat sink 30 can be attached to the upper surface 10a of the substrate 10, the manufacturer of the circuit board 2 can easily attach the heat sink 30 to the inductors 1, 101 and 201. be able to.

According to the above embodiment, the internal conductor 25 extending linearly in a plan view is exposed from the mounting surface 10b to the outside of the substrate 10 and is connected to the external electrodes 21 and 22. Therefore, the current flowing from the land 3a to the inner conductor 25 via the outer electrode 21 passes through the inner conductor 25 and flows to the land 3b via the outer electrode 22. As described above, the current flowing through the inductors 1, 101 and 201 is a small distance between the land 3a and one end of the internal conductor 25 and between the land 3b and the other end of the internal conductor 25 (of the external electrodes 21 and 22). The external electrodes 21 and 22 flow by the distance (distance corresponding to the thickness in the T-axis direction). Generally, the outer electrode of an inductor is made of a material that has a lower electrical conductivity than the inner conductor. Further, the portion of the external electrode in contact with the end surface (the surface connecting the mounting surface and the upper surface) of the substrate has a cross-sectional area smaller than that of the internal conductor. Therefore, when the inner conductor is exposed from the end face of the substrate like a conventional inductor in which the inner conductor extends linearly, the current passes through the outer electrode in the section from the exposed position of the inner conductor to the land. Since the distance from the exposed position of the internal conductor to the land on the end surface of the substrate is longer than the distance from the mounting surface of the substrate to the land, the external electrode interposed in the section from the exposed position of the internal conductor to the land is the DC resistance of the inductor. It becomes an increase factor of. In the inductors 1, 101, 201 according to the embodiment of the present invention, since the internal conductor 25 is exposed from the mounting surface 10b of the substrate 10, the current passing through the inductors 1, 101, 201 is the land 3a and the internal conductor 25. Passes through the external electrodes 21 and 22 only a short distance between one end of the land 3b and the inner conductor 25. As described above, according to the inductors 1, 101 and 201, since the ratio of the external electrodes 21 and 22 to the current path is smaller than that of the conventional inductor, the DC resistance can be reduced as compared with the conventional inductor.

When the Fe content in the Fe-based metal magnetic particles contained in the substrate 10 is 80 wt% or more, the ratio of the metal magnetic particles to the inductors 1, 101, and 201 can be increased, and the current value per unit volume can be increased. .. Inductors 1, 101 and 201 can be used in applications where, for example, a current value of 0.15 A / mm 3 or more per unit volume is required. The current value per unit volume is the value obtained by dividing the saturation current value by the volume of the inductor. The saturation current value is the DC current when the inductance is reduced by 30% from the initial value due to the application of the DC current, with the inductance when no DC current is applied to the inductor as the initial value. Assuming that the Fe content in the metal magnetic particles contained in the substrate 10 is 85 wt% or more, the inductors 1, 101, and 201 are used in applications where a current value of 0.2 A / mm 3 or more per unit volume is required. obtain. If the Fe in the metal magnetic particles contained in the substrate 10 is 90 wt% or more, the inductors 1, 101, and 201 can be used in applications that require a current value of 0.25 A / mm 3 or more per unit volume. As described above, since magnetic saturation is suppressed in the substrate 10 of the inductor 1 according to one or more embodiments of the present invention, a large current can be passed through the internal conductor 25. For example, when the inductance L of the inductor 1 is made smaller than 300 nH, the current value per unit volume ^{can be 0.15 A / mm 3} or more. Further, when the inductance L of the inductor 1 is made smaller than 150 nH, the current value per unit volume ^{can be set to 0.2 A / mm 3} or more. Further, when the inductance L of the inductor 1 is made smaller than 75 nH, the current value per unit volume ^{can be set to 0.25 A / mm 3} or more. In the inductors 1, 101, and 201 including the substrate 10 containing the metal magnetic particles having a Fe content of 80 wt% or more, the change in inductance due to the application of a current is small, and the heat generation is small. Further, it can be used for high frequency applications, for example, a frequency of 5 MHz or higher.

The substrate 10 may be formed of a composite magnetic material containing metal magnetic particles and a binder. When the substrate 10 is formed of a composite magnetic material, the binder contained in the composite magnetic material may be 5 wt% or less, 4 wt% or less, 3 wt% or less, or 2 wt% or less, and the balance may be composed of metal magnetic particles. it can. By reducing the proportion of the binder, the heat conduction of the substrate 10 can be improved, and the heat dissipation characteristics of the inductors 1, 101, and 201 when a current is applied can be improved. For example, assuming that the thermal conductivity of the substrate 10 containing 10 wt% of the binder is 1, the thermal conductivity of the substrate 10 containing 5 wt% of the binder is 1.3, and the heat of the substrate 10 containing 4 wt% of the binder is 1. The conductivity is 1.4, the thermal conductivity of the substrate 10 containing the 3 wt% binder is 1.5, and the thermal conductivity of the substrate 10 containing the 2 wt% binder is 1.6. By using an inorganic material as the material of the binder, the thermal conductivity of the substrate 10 can be increased as compared with the case where an organic material is used as the material of the binder, and the heat dissipation characteristics can be further improved. The heat generated by the inductor is generated by the application of a current and the resistance component of the internal conductor 25, and the larger the current, the larger the heat generated.

Further, by reducing the proportion of the binder in the substrate 10, the magnetic path cross section per unit cross section in the substrate 10 can be increased, so that magnetic saturation at the time of applying a current can be prevented from occurring. That is, by reducing the proportion of the binder in the substrate 10, magnetic saturation is less likely to occur and heat dissipation characteristics can be improved.

When the inductors 1, 101, and 201 are mounted on the circuit board 2, the end face of the inner conductor 25 in contact with the outer electrode 21 and the land 3a of the circuit board 2 face each other, and the end face of the inner conductor 25 in contact with the outer electrode 22. By facing the lands 3b of the circuit board 2, not only the heat generation of the inductors 1, 101, 201 can be suppressed, but also the heat generation in the region between the inductors 1, 101, 201 and the lands 3a, 3b can be suppressed. it can. Even if the external electrodes 21 and 22 between the inductors 1, 101 and 201 and the lands 3a and 3b are formed of a material having low electrical conductivity, heat generation in the external electrodes 21 and 22 when a current is applied can be suppressed. ..

In a conventional inductor having an internal conductor extending linearly, when cut in a cross section extending in the direction corresponding to the WT direction in FIG. 1, the cross-sectional shape of the internal conductor and the cross-sectional shape of the magnetic substrate are similar to each other. By arranging the inner conductor in the center of the magnetic substrate, it is possible to prevent the occurrence of local magnetic saturation in the substrate, thereby obtaining excellent DC superimposition characteristics. However, when the inner conductor is pulled out from the mounting surface, it is difficult to make the cross-sectional shape of the inner conductor and the cross-sectional shape of the magnetic substrate similar. On the other hand, in the embodiment of the present invention, the ratio of the area S2 of the second region 10r2 between the inner conductor 25 and the upper surface 10a to the area S1 of the first region 10r1 between the inner conductor 25 and the mounting surface 10b. By configuring and arranging the inner conductor 25 so that (S2 / S1) is in the range of 0.95 to 1.1, magnetic saturation occurs intensively in one of the first region 10r1 and the second region 10r2. I try not to. As a result, deterioration of the DC superimposition characteristics of the inductors 1, 101, and 201 can be prevented or suppressed even if the internal conductor 25 is pulled out from the mounting surface 10b. The reason why the range of the area ratio S2 / S1 is biased upward rather than vertically around 1.0 is that the area of the second region 10r2 contributes to the improvement of the saturation magnetic flux when the internal conductor 25 is pulled out. This is because small strip areas (eg, strip areas SR1 and SR2 shown in FIGS. 5-9) are often included. When narrow strip regions SR1 and SR2 are present in the substrate 10, magnetic saturation occurs immediately in the strip regions SR1 and SR2, so the areas S3 and S4 of the strip regions SR1 and SR2 are excluded from the area of the second region 10r2. By configuring and arranging the inner conductor 25 so that the ratio of the area of the first region ((S2-S3-S4) / S1) to the combined area is in the range of 0.86 to 1.0, the first region 10r1 It is possible to prevent intensive magnetic saturation from occurring on the one side of the second region 10r2.

According to the above embodiment, since at least one of the external electrode 21 and the external electrode 22 is provided so as to be in contact with only the mounting surface 10b, the external electrode 21 is provided on the first end surface 10c and the second end surface 10d of the substrate 10. , 22 are not in contact. As a result, when the dimensions of the inductors 1, 101, and 201 in the L-axis direction are determined, the dimensions of the substrate 10 in the L-axis direction can be increased by the width of the external electrodes 21 and 22.

According to the above embodiment, the distance d1 between the inner conductor 125A and the inner conductor 125B in the W-axis direction is smaller than at least one of the thickness of the inner conductor 125A and the thickness of the inner conductor 125B. In this case, since the distance between the inner conductor 125A and the inner conductor 125B is smaller than the thickness of the inner conductor 125A and the inner conductor 125B, the coupling coefficient between the coil including the inner conductor 125A and the coil including the inner conductor 125B is small. Can be raised.

According to the above embodiment, the distance d2 between the inner conductor 225A and the inner conductor 225B in the T-axis direction is smaller than at least one of the width of the inner conductor 225A and the width of the inner conductor 225B. In this case, since the distance between the inner conductor 225A and the inner conductor 225B is smaller than the thickness of the inner conductor 225A and the inner conductor 225B, the coupling coefficient between the coil including the inner conductor 225A and the coil including the inner conductor 225B is small. Can be enhanced.

According to the above embodiment, the magnetic permeability of the interconductor region 10R1 (or the interconductor region 10R3) of the substrate 10 is in the peripheral region 10R2 (or the peripheral region 10R4) other than the interconductor region 10R1 (or the interconductor region 10R3). Lower than magnetic permeability. As a result, the amount of magnetic flux passing through the interconductor region 10R1 (or the interconductor region 10R3) can be reduced, and as a result, the coupling coefficient between the two coils can be increased.

According to the above embodiment, in the plan view of the substrate 10 of the inductors 1, 101, 201 (from the viewpoint seen from the T axis), the first side surface 10e of the substrate 10 and the first side surface 10e of the inner conductor 25 The area of the region 10Re surrounded by the surface facing the first end surface 10c and the second end surface 10d is the surface facing the second side surface 10f of the substrate 10 and the second side surface 10f of the inner conductor 25. Is equal to the area of the region 10Rf surrounded by the first end surface 10c and the second end surface 10d. By making the area of the region 10Re equal to the area of the region 10Rf on the second side surface 10f side in this way, the magnetic flux density of the region 10Re and the magnetic flux density of the region 10Rf can be made the same or substantially the same. it can. Therefore, it is possible to suppress the intensive magnetic saturation in one of the region 10Re and the region 10Rf.

The dimensions, materials, and arrangement of each component described herein are not limited to those expressly described in the embodiments, and each component may be included within the scope of the present invention. Can be transformed to have the dimensions, materials, and arrangement of. In addition, components not explicitly described in the present specification may be added to the described embodiments, or some of the components described in each embodiment may be omitted.

1, 101, 201 Inductor 2 Circuit board 3a, 3b Land 10 Base 10a Top surface 10b Mounting surface 10r1 First area 10r2 Second area 21, 22, 121a, 121b, 122a, 122b, 221a, 221b, 222a, 222b External electrode 25 , 125A, 125B, 225A, 225B Internal conductor 25a-25f Internal conductor pattern 30 Heat sink

Claims (20)

A substrate having a mounting surface facing the circuit board, an upper surface facing the mounting surface, and an end surface connecting the mounting surface and the upper surface.
A first external electrode attached to the mounting surface of the substrate,
A second external electrode attached to the mounting surface of the substrate at a distance from the first external electrode in a length direction perpendicular to the end surface.
It is provided in the substrate and extends linearly from the first external electrode toward the second external electrode in a plan view viewed from a thickness direction perpendicular to the mounting surface, and one end is exposed from the mounting surface. An internal conductor connected to the first external electrode and the other end exposed from the mounting surface and connected to the second external electrode.
With
The shortest distance between the axis of the inner conductor and the upper surface in the front view seen from the width direction perpendicular to the thickness direction and the length direction is more than half of the distance between the upper surface and the mounting surface. Is also small
Inductor. The substrate extends in parallel with the mounting surface and the upper surface, and has an upper region between the intermediate surface and the upper surface by an intermediate surface equidistant from the mounting surface and the upper surface, and the intermediate surface and the mounting. Divided into a lower area between the faces
The internal conductor is located between a first portion connected to the first external electrode, a second portion connected to the second external electrode, and the first portion and the second portion, and is located in the upper region. Has a third part, which is located in
The inductor according to claim 1. The substrate has a dimension in the length direction larger than a dimension in the height direction.
The inductor according to claim 1 or 2. In the inner conductor, the distance between the axis and the upper surface is smaller than half of the distance between the upper surface and the mounting surface in a region of 50% or more of the substrate in the length direction.
The inductor according to any one of claims 1 to 3. The inner conductor is formed of a conductive material having a higher electrical conductivity than the material of the first outer electrode.
The inductor according to any one of claims 1 to 4. Each of the inner peripheral surface and the outer peripheral surface of the inner conductor is composed of only curved lines in the front view seen from the width direction.
The inductor according to any one of claims 1 to 5. The first external electrode is attached to the substrate only on the mounting surface.
The inductor according to any one of claims 1 to 6. The second external electrode is attached to the substrate only on the mounting surface.
The inductor according to any one of claims 1 to 7. The substrate is configured so that a heat sink can be provided on the upper surface thereof.
The inductor according to any one of claims 1 to 8. The substrate contains metallic magnetic particles.
The inductor according to any one of claims 1 to 9. The inner conductor has a first inner conductor pattern and a second inner conductor pattern arranged in the substrate at a distance from the inner conductor pattern.
Each of the first inner conductor pattern and the inner conductor pattern extends linearly from the first outer electrode toward the second outer electrode in a plan view viewed from a thickness direction perpendicular to the mounting surface, and one end thereof is It is exposed from the mounting surface and connected to the first external electrode, and the other end is exposed from the mounting surface and connected to the second external electrode.
The inductor according to any one of claims 1 to 10. A third external electrode attached to the mounting surface of the substrate,
A fourth external electrode attached to the mounting surface of the substrate at a distance from the third external electrode in a length direction perpendicular to the end surface.
It is provided in the substrate and extends linearly from the third external electrode toward the fourth external electrode in a plan view viewed from a thickness direction perpendicular to the mounting surface, and one end is exposed from the mounting surface. With another internal conductor connected to the third external electrode and the other end exposed from the mounting surface and connected to the fourth external electrode.
With
When viewed from the front in the width direction, the shortest distance between the axis of the other inner conductor and the upper surface is smaller than half of the distance between the upper surface and the mounting surface.
The inductor according to any one of claims 1 to 11. The distance between the inner conductor and the other inner conductor in the width direction is smaller than at least one of the thickness of the inner conductor and the thickness of the other inner conductor.
The inductor according to claim 12. A third external electrode attached between the first external electrode and the second electrode on the mounting surface of the substrate,
A fourth external electrode attached between the first external electrode and the second electrode on the mounting surface of the substrate so as to be separated from the third external electrode in a length direction perpendicular to the end surface.
It is provided in the substrate and extends linearly from the third external electrode toward the fourth external electrode in a plan view viewed from a thickness direction perpendicular to the mounting surface, and one end is exposed from the mounting surface. With another internal conductor connected to the third external electrode and the other end exposed from the mounting surface and connected to the fourth external electrode.
With
When viewed from the front in the width direction, the shortest distance between the axis of the other inner conductor and the upper surface is smaller than half of the distance between the upper surface and the mounting surface.
The inductor according to any one of claims 1 to 11. The distance between the inner conductor and the other inner conductor in the thickness direction is smaller than at least one of the width of the inner conductor and the width of the other inner conductor.
The inductor according to claim 14. The magnetic permeability of the interconductor region between the inner conductor and the other inner conductor of the substrate is lower than the magnetic permeability in the region other than the interconductor region.
The inductor according to any one of claims 12 to 15. The inner conductor is in direct contact with the substrate,
The inductor according to any one of claims 1 to 16. The substrate contains a binder made of an inorganic material.
The inductor according to any one of claims 1 to 17. A circuit board comprising the inductor according to any one of claims 1 to 18. An electronic device comprising the circuit board according to claim 19.

Images