Coil components

Abstract

To provide a coil component with reduced stray capacitance. [Solution] In the coil component 1, the length h1 of the outer surface 36a of the winding 36 of each planar coil section 31A, 31B, 33A, 33B is shorter than the length h2 of the inner surface 36b. Therefore, compared to the case where the outer surface 36a and the inner surface 36b have the same length h2, for example, the opposing area of ​​the two windings 36 is reduced, thereby reducing the stray capacitance that occurs between the two windings 36.

Description

TECHNICAL FIELD

[0001] The present invention relates to a coil component. BACKGROUND ART

[0002] Patent Document 1 below discloses a coil component that includes a coil having a spiral first coil portion formed on one surface of an insulating substrate provided in a body, a spiral second coil portion formed on the other surface of the insulating substrate, and a through-hole conductor penetrating the insulating substrate to electrically connect the first coil portion and the second coil portion, and a pair of external terminals provided on the surface of the body and respectively connected to both end portions of the coil. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] PATENT DOCUMENT 1 U.S. Patent Application Publication No. 2024 / 0224023 Specification SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In the coil component as described above, stray capacitance may occur between various conductors constituting the coil component. As a result of intensive studies, the inventors have newly found a technique capable of reducing stray capacitance.

[0005] Various aspects of the present invention aim to provide a coil component with reduced stray capacitance. MEANS FOR SOLVING THE PROBLEMS

[0006] A coil component according to one aspect of the present invention comprises a base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces; an insulating substrate provided inside the base body, extending parallel to the main surfaces of the base body and having a first main surface and a second main surface facing the pair of main surfaces of the base body, respectively; a coil structure provided inside the base body and having a first coil including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion; and a first external terminal provided on the first end surface and electrically connected to the outer end of the first coil portion, wherein, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the outermost winding of the second coil portion is shorter than the length of the inner surface.

[0007] A coil component according to one aspect of the present invention comprises a base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces; an insulating substrate provided inside the base body, extending parallel to the main surfaces of the base body and having a first main surface and a second main surface facing the pair of main surfaces of the base body, respectively; a coil structure provided inside the base body and having a first coil including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion; a first external terminal provided on the first end surface and electrically connected to the outer end of the first coil; and a pair of conductors provided on the second main surface of the insulating substrate in close proximity to the first end surface and electrically connected to the first external terminal, wherein, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the outermost winding of the second coil portion is shorter than the length of the inner surface.

[0008] A coil component according to one aspect of the present invention comprises a base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces; an insulating substrate provided inside the base body, extending parallel to the main surfaces of the base body and having a first main surface and a second main surface facing the pair of main surfaces of the base body, respectively; and a coil structure provided inside the base body, having a first coil including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion, wherein at least one of the first coil portion and the second coil portion includes a first winding and a second winding adjacent to the outer circumference of the first winding, and with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the first winding is shorter than the length of the inner surface.

[0009] In the above coil component, with respect to the length in the thickness direction of the insulating substrate, the length of at least some of the outer surface of the winding is shorter than the length of the inner surface, and the stray capacitance generated between the outer surface of the winding and the opposing conductor is reduced as the opposing area is reduced. [Effects of the Invention]

[0010] According to various aspects of the present invention, a coil component is provided in which the stray capacitance is reduced. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic perspective view of a coil component according to an embodiment. [Figure 2] Figure 2 shows the inside of the coil component shown in Figure 1. [Figure 3] Figure 3 is an exploded view of the coil shown in Figure 2. [Figure 4] Figure 4 is a plan view of the inside of the coil component shown in Figure 2. [Figure 5] Figure 5 is a cross-sectional view of the coil component shown in Figure 2, along the VV line. [Figure 6] Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 4. [Figure 7] Figure 7 is a cross-sectional view taken along line VII-VII in Figure 4. [Figure 8] Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 4. [Figure 9] Figure 9 is a cross-sectional view taken along the line IX-IX in Figure 4. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below with reference to the attached drawings. In the description, the same reference numerals will be used for elements that are the same or have the same function, and redundant descriptions will be omitted.

[0013] The coil component 1 according to this embodiment is a balun coil. Balun coils are used, for example, when mounting a near-field communication (NFC) circuit in a cellular terminal. The balun coil performs a conversion between the unbalanced signal of the antenna and the balanced signal of the NFC circuit, thereby realizing a connection between the unbalanced circuit and the balanced circuit.

[0014] As shown in Figures 1 to 5, the coil component 1 comprises a base body 10, an insulating substrate 20 embedded within the base body 10, a coil structure 30 provided on the insulating substrate 20 within the base body 10, and two pairs of external terminal electrodes 60A, 60B, 60C, and 60D provided on the surface of the base body 10.

[0015] The base body 10 has a rectangular parallelepiped shape and six faces 10a to 10f. For example, the base body 10 is designed with dimensions of 2.0 mm on the long side, 1.25 mm on the short side, and 0.65 mm in height. Of the faces 10a to 10f of the base body 10, the end face 10a (first end face) and the end face 10b (second end face) are parallel to each other, the top face 10c and the bottom face 10d are parallel to each other, and the side faces 10e and 10f are parallel to each other. The top face 10c of the base body 10 is the face that faces the mounting surface of the mounting board on which the coil component 1 is mounted, parallel to each other.

[0016] The element body 10 is composed of a metal magnetic powder-containing resin 12 which is a type of magnetic material. The metal magnetic powder-containing resin 12 is a bound powder in which metal magnetic powder is bound by a binder resin. The metal magnetic powder of the metal magnetic powder-containing resin 12 is composed of, for example, iron-nickel alloy (permalloy alloy), carbonyl iron, amorphous material, amorphous or crystalline FeSiCr-based alloy, sendust, or the like. The binder resin is, for example, a thermosetting epoxy resin. In the present embodiment, the content of the metal magnetic powder in the bound powder is 80 to 92 vol% in volume percent, and 95 to 99 wt% in mass percent. From the viewpoint of magnetic properties, the content of the metal magnetic powder in the bound powder may be 85 to 92 vol% in volume percent, and 97 to 99 wt% in mass percent. The magnetic powder of the metal magnetic powder-containing resin 12 may be a powder having one type of average particle diameter, or may be a mixed powder having a plurality of types of average particle diameters.

[0017] The metal magnetic powder-containing resin 12 of the element body 10 integrally covers an insulating substrate 20 and a coil structure 30 which will be described later. Specifically, the metal magnetic powder-containing resin 12 covers the coil structure 30 from the vertical direction, and also covers the outer periphery of the coil structure 30. Further, the metal magnetic powder-containing resin 12 fills the inner peripheral region of the coil structure 30.

[0018] The insulating substrate 20 has a flat plate shape, extends across the end faces 10a and 10b of the element body 10, and is designed to be orthogonal to the end faces 10a and 10b. The insulating substrate 20 extends parallel to the upper surface 10c and the lower surface 10d of the element body 10. As shown in FIG. 3, the insulating substrate 20 includes an elliptical annular coil forming portion 21 extending along the long side direction of the element body 10, and a pair of frame portions 24A and 24B extending along the short side direction of the element body 10 and sandwiching the coil forming portion 21 from both sides. An elliptical opening 22 extending along the long side direction of the element body 10 is provided in the central portion of the coil forming portion 21.

[0019] The insulating substrate 20 is made of a non-magnetic insulating material. The thickness of the insulating substrate 20 can be designed to be in the range of 10 to 60 μm, for example. In the present embodiment, the insulating substrate 20 has a configuration in which a glass cloth is impregnated with an epoxy-based resin. The resin constituting the insulating substrate 20 is not limited to an epoxy-based resin, and may be BT resin, polyimide, aramid, or the like. The constituent material of the insulating substrate 20 may be ceramic or glass. The constituent material of the insulating substrate 20 may be a mass-produced printed circuit board material. The constituent material of the insulating substrate 20 may be a resin material used for a BT printed board, an FR4 printed board, or an FR5 printed board.

[0020] The coil structure 30 includes a first coil C1 and a second coil C2 that constitute a double coil structure. The first coil C1 includes a planar spiral first planar coil portion 31A (first coil portion) provided on the upper surface 20a (first main surface) of the insulating substrate 20, a planar spiral second planar coil portion 31B (second coil portion) provided on the lower surface 20b (second main surface) of the insulating substrate 20, and a first through-conductor 32 (first through-hole conductor) that connects the first planar coil portion 31A and the second planar coil portion 31B. The second coil C2 includes a planar spiral third planar coil portion 33A (third coil portion) provided on the upper surface 20a of the insulating substrate, a planar spiral fourth planar coil portion 33B (fourth coil portion) provided on the lower surface 20b of the insulating substrate 20, and a second through-conductor 34 (third through-hole conductor) that connects the third planar coil portion 33A and the fourth planar coil portion 33B.

[0021] On the upper surface 20a of the insulating substrate 20, the first planar coil portion 31A of the first coil C1 and the third planar coil portion 33A of the second coil C2 are wound adjacent to each other in parallel. Further, on the lower surface 20b of the insulating substrate 20, the second planar coil portion 31B of the first coil C1 and the fourth planar coil portion 33B of the second coil C2 are wound adjacent to each other in parallel.

[0022] The first planar coil portion 31A is a substantially oval spiral air-core coil wound around the opening 22 of the coil forming portion 21 within the same layer on the upper surface 20a of the insulating substrate 20. The number of turns of the first planar coil portion 31A may be one turn or multiple turns. In this embodiment, the number of turns of the first planar coil portion 31A is 3 to 4. The first planar coil portion 31A has an outer end 31a and an inner end 31b. The outer end 31a is provided on the frame portion 24A and is exposed from the end face 10a of the base body 10. The inner end 31b is provided on the edge of the opening 22. The insulating substrate 20 is provided with a first through conductor 32 that extends in the thickness direction of the insulating substrate 20 at a position overlapping with the inner end 31b of the first planar coil portion 31A. The first planar coil portion 31A is made of, for example, Cu and can be formed by electroplating. The first through-conductor 32 may consist of a hole provided in the insulating substrate 20 and a conductive material (for example, a metallic material such as Cu) filled in the hole.

[0023] The second planar coil section 31B is symmetrical to the first planar coil section 31A. More specifically, the second planar coil section 31B has a shape that is an inversion of the first planar coil section 31A around an axis parallel to the short side of the base body 10. The outer end 31a of the second planar coil section 31B is provided on the frame section 24B and is exposed from the end face 10b of the base body 10. The inner end 31b of the second planar coil section 31B overlaps with the first through-conductor 32 provided on the insulating substrate 20. Therefore, the inner end 31b of the second planar coil section 31B is electrically connected to the inner end 31b of the first planar coil section 31A via the first through-conductor 32. In the first coil C1, the outer end 31a of the first planar coil section 31A constitutes the first end, and the outer end 31a of the second planar coil section 31B constitutes the second end. The third planar coil portion 33A is made of, for example, Cu and can be formed by electroplating.

[0024] The third planar coil section 33A, like the first planar coil section 31A, is a substantially oval spiral air-core coil wound around the opening 22 of the coil forming section 21 on the upper surface 20a of the insulating substrate 20, within the same layer. The third planar coil section 33A is wound on the inner circumference side of the first planar coil section 31A, adjacent to the first planar coil section 31A. The number of turns of the third planar coil section 33A may be one turn or multiple turns. In this embodiment, the number of turns of the third planar coil section 33A is the same as the number of turns of the first planar coil section 31A. The third planar coil section 33A has an outer end 33a and an inner end 33b. The outer end 33a of the third planar coil section 33A, like the outer end 31a of the first planar coil section 31A, is provided on the frame section 24A and is exposed from the end face 10a of the base body 10. The inner end 33b of the third planar coil portion 33A is located at the edge of the opening 22 and is adjacent to the inner end 31b of the first planar coil portion 31A. The insulating substrate 20 is provided with a second through-conductor 34 that extends in the thickness direction of the insulating substrate 20 at a position overlapping with the inner end 33b of the third planar coil portion 33A. The third planar coil portion 33A, like the first planar coil portion 31A, is made of, for example, Cu and may be formed by electroplating. The second through-conductor 34 may consist of a hole provided in the insulating substrate 20 and a conductive material (for example, a metallic material such as Cu) filled in the hole.

[0025] The fourth planar coil section 33B is symmetrical with the third planar coil section 33A. More specifically, the fourth planar coil section 33B has a shape that is an inversion of the third planar coil section 33A around an axis parallel to the short side of the base body 10. The outer end 33a of the fourth planar coil section 33B is provided on the frame section 24B and is exposed from the end face 10b of the base body 10. The inner end 33b of the fourth planar coil section 33B overlaps with the second through-conductor 34 provided on the insulating substrate 20. Therefore, the inner end 33b of the fourth planar coil section 33B is electrically connected to the inner end 33b of the third planar coil section 33A via the second through-conductor 34. In the second coil C2, the outer end 33a of the third planar coil section 33A constitutes the first end, and the outer end 33a of the fourth planar coil section 33B constitutes the second end. The fourth planar coil portion 33B is made of, for example, Cu and can be formed by electroplating.

[0026] In this embodiment, four pairs of conductors 40 are formed on the insulating substrate 20. Each pair of conductors 40 overlaps with the outer ends 31a, 33a of the four planar coil sections 31A, 31B, 33A, and 33B via the insulating substrate 20. The pairs of conductors 40 and the outer ends 31a, 33a are connected to each other by through-conductors 35 (second through-hole conductors) provided in the insulating substrate 20. The pairs of conductors 40 are made of, for example, Cu, and may be formed by electrolytic plating when the planar coil sections 31A, 31B, 33A, and 33B are formed by electrolytic plating. Each pair of conductors 40 has the same shape as the outer ends 31a, 33a when viewed from the thickness direction of the insulating substrate 20. The outer ends 31a, 33a of the four planar coil sections 31A, 31B, 33A, and 33B are each doubled by the four pairs of conductors 40, improving electrical connectivity with the external terminal electrodes 60A to 60D. The through conductor 35 may be positioned away from the end faces 10a and 10b and not exposed from the end faces 10a and 10b, or it may be exposed from the end faces 10a and 10b. If the through conductor 35 is not exposed from the end faces 10a and 10b, the through conductor 35 and the external terminal electrodes 60A to 60D will not be in direct contact, and a part of the insulating substrate 20 will be interposed between the through conductor 35 and the external terminal electrodes 60A to 60D. Since the adhesion force between the external terminal electrodes 60A to 60D and the insulating substrate 20 is stronger than the adhesion force between the external terminal electrodes 60A to 60D and the through conductor 35, the adhesion force of the external terminal electrodes 60A to 60D to the base body 10 can be increased by positioning the through conductor 35 so that it is not exposed from the end faces 10a and 10b. It is not necessary to double the outer ends 31a, 33a of all four planar coil sections 31A, 31B, 33A, and 33B; it is also acceptable to double only the outer ends 31a, 33a of some of the planar coil sections 31A, 31B, 33A, and 33B. The shape of each pair of conductors 40 may be such that it completely overlaps with the outer ends 31a, 33a when viewed from the thickness direction of the insulating substrate 20, or it may be such that it partially overlaps.

[0027] The first planar coil portion 31A and the third planar coil portion 33A, provided on the upper surface 20a of the insulating substrate 20, are integrally covered by the first insulator 50A. The first insulator 50A covers the inner and outer surfaces of each winding of the first planar coil portion 31A and the third planar coil portion 33A, and includes a plurality of resin walls that fill the space between adjacent windings of the first planar coil portion 31A and the third planar coil portion 33A. The resin walls of the first insulator 50A are composed of thick film resist patterned by known photolithography, and define the plating growth regions of the first planar coil portion 31A and the third planar coil portion 33A. In this embodiment, the first insulator 50A also covers the surface of the pair conductor 40 provided on the upper surface 20a of the insulating substrate 20. The second planar coil portion 31B and the fourth planar coil portion 33B, provided on the lower surface 20b of the insulating substrate 20, are integrally covered by the second insulator 50B. The second insulator 50B covers the inner and outer surfaces of the windings of the third planar coil portion 33A and the fourth planar coil portion 33B, and includes a plurality of resin walls that fill the space between the adjacent windings of the second planar coil portion 31B and the windings of the fourth planar coil portion 33B. The resin walls of the second insulator 50B, like the resin walls of the first insulator 50A, are composed of a thick film resist patterned by known photolithography, and define the plating growth regions of the second planar coil portion 31B and the fourth planar coil portion 33B. In this embodiment, the second insulator 50B also covers the surface of the pair conductor 40 provided on the lower surface 20b of the insulating substrate 20. The first insulator 50A and the second insulator 50B can be made of, for example, an epoxy resin.

[0028] Two pairs of external terminal electrodes 60A to 60D are provided one pair each on the end faces 10a and 10b of the main body 10, and are connected to the outer ends 31a, 33a of the corresponding planar coil sections 31A, 31B, 33A, and 33B, and to the paired conductors 40, respectively. Specifically, the external terminal electrode 60A provided on end face 10a is connected to the outer end 31a of the first planar coil section 31A, the external terminal electrode 60B provided on end face 10a alongside the external terminal electrode 60A is connected to the outer end 33a of the third planar coil section 33A, the external terminal electrode 60C provided on end face 10b is connected to the outer end 31a of the second planar coil section 31B, and the external terminal electrode 60D provided on end face 10b alongside the external terminal electrode 60C is connected to the outer end 33a of the fourth planar coil section 33B. The external terminal electrodes 60A on end face 10a and 60C on end face 10b are located at corresponding positions in the long-side direction of the base body 10. Similarly, the external terminal electrodes 60B on end face 10a and 60D on end face 10b are located at corresponding positions in the long-side direction of the base body 10. The external terminal electrodes 60A, 60B, 60C, and 60D are all bent in an L-shape and continuously cover the end faces 10a, 10b and the top surface 10c. In this embodiment, the external terminal electrodes 60A, 60B, 60C, and 60D are made of resin electrodes, for example, a resin containing Ag powder.

[0029] As shown in Figures 6-9, in this embodiment, the windings 36 of each planar coil section 31A, 31B, 33A, and 33B have a substantially rectangular cross-sectional shape, specifically having an outer surface 36a facing the outer circumference of the coil, an inner surface 36b facing the center of the coil, a lower surface 36c in contact with the main surfaces 20a and 20b of the insulating substrate 20, and an upper surface 36d. The upper surface 36d of the winding 36 is the surface that faces the lower surface 36c in the thickness direction of the insulating substrate 20, on the side away from the insulating substrate 20. In this embodiment, with respect to the length (i.e., height) in the thickness direction of the insulating substrate 20, the length h1 of the outer surface 36a of the windings 36 of each planar coil section 31A, 31B, 33A, and 33B is shorter than the length h2 of the inner surface 36b. In this embodiment, the difference between the length of the outer surface 36a and the length of the inner surface 36b between multiple windings 36 may be the same, or the difference between the length of the outer surface 36a and the length of the inner surface 36b may be different. In addition, the upper surface 36d of the windings 36 of each planar coil section 31A, 31B, 33A, 33B is inclined with respect to the main surfaces 20a, 20b of the insulating substrate 20, that is, it is inclined to go down (closer to the insulating substrate 20) from the inner surface 36b side towards the outer surface 36a side. In this embodiment, the thickness of the insulators 50A, 50B (resin bodies) covering the upper surface 36d of the windings 36 of each planar coil section 31A, 31B, 33A, 33B increases from the inner surface 36b side towards the outer surface 36a side. The degree of inclination of the upper surface 36d between multiple windings 36 may be the same or different.

[0030] As shown in Figures 6-9, when there is one winding 36 (first winding) and an adjacent winding 36 (second winding) on ​​the outer circumference of the first winding 36, stray capacitance can occur between the two windings 36 (the resin wall in this embodiment). In this embodiment, since the length h1 of the outer surface 36a of the winding 36 is shorter than the length h2 of the inner surface 36b, the opposing area of ​​the two windings 36 is reduced compared to, for example, the case where the outer surface 36a and the inner surface 36b have the same length h2, thereby reducing the stray capacitance that occurs between the two windings 36. In particular, when viewed from the thickness direction of the insulating substrate 20, the total length of the outer surface 36a of the winding 36 is longer than the total length of the inner surface 36b, so shortening the length h1 of the outer surface 36a has a greater effect on reducing the opposing area than shortening the length h2 of the inner surface 36b.

[0031] Furthermore, as shown in Figures 6-9, when the outer surface 36a of the winding 36 (outermost winding) located on the outermost periphery of the planar coil sections 31A and 31B faces the outer end 33a of each planar coil section 31A, 31B, 33A, and 33B on the upper surface 20a or lower surface 20b of the insulating substrate 20, stray capacitance may occur between the outermost winding 36 and the outer end 31a and 33a. In this embodiment, since the length h1 of the outer surface 36a of the winding 36 is shorter than the length h2 of the inner surface 36b, for example, the area of ​​contact between the outermost winding 36 and the outer end 31a and 33a is reduced compared to the case where the outer surface 36a and the inner surface 36b have the same length h2, thus reducing the stray capacitance that occurs between the two windings 36.

[0032] In this embodiment, the gap between the outermost winding 36 of the planar coil sections 31A and 31B and the outer end 33a of the insulating substrate 20 is interposed by the metal magnetic powder-containing resin 12 that constitutes the base body 10 (more specifically, the metal magnetic powder-containing resin 12 and insulators 50A and 50B are interposed). However, the gap between the outermost winding 36 of the planar coil sections 31A and 31B and the outer end 33a may be filled with the material that constitutes the insulators 50A and 50B. The interposition of the metal magnetic powder-containing resin 12 that constitutes the base body 10 in the gap between the outermost winding 36 of the planar coil sections 31A and 31B and the outer end 33a reduces the leakage magnetic flux generated between the outer end 33a and the outermost winding 36, increasing the mutual inductance and thereby improving the coupling coefficient.

[0033] As shown in Figures 6-9, in this embodiment, each pair of conductors 40 has a substantially rectangular cross-sectional shape, specifically a surface 40a (first side surface) that faces the outer surface 36a of the winding 36 on the side away from the end faces 10a and 10b, a surface 40b (second side surface) that is closer to or exposed to the end faces 10a and 10b, a lower surface 40c that contacts the main surfaces 20a and 20b of the insulating substrate 20, and an upper surface 40d. The upper surface 40d of the pair of conductors 40 is the surface that faces the lower surface 40c in the thickness direction of the insulating substrate 20 on the side away from the insulating substrate 20. In this embodiment, with respect to the length (i.e., height) of the insulating substrate 20 in the thickness direction, the length h3 of the surface 40a (first side surface) that faces the outer surface 36a of the winding 36 on the side away from the end faces 10a and 10b of the pair conductor 40 is shorter than the length h4 of the surface 40b (second side surface) that is closer to the end faces 10a and 10b.

[0034] As shown in Figures 6-9, when the surface 40a of the pair conductor 40 and the outer surface 36a of the outermost winding 36 of the planar coil sections 31A and 31B face each other on the upper surface 20a or lower surface 20b of the insulating substrate 20, stray capacitance may occur between the pair conductor 40 and the outermost winding 36. In this embodiment, in addition to the length h1 of the outer surface 36a of the winding 36 being shorter than the length h2 of the inner surface 36b, the length h3 of the surface 40a of the pair conductor 40 being shorter than the length h4 of the surface 40b, the area of ​​contact between the pair conductor 40 and the outermost winding 36 is reduced, thereby reducing the stray capacitance that occurs between the pair conductor 40 and the outermost winding 36.

[0035] In addition, the paired conductors 40 can be omitted. In this case, the outermost winding 36 of each planar coil section 31A, 31B will face the external terminal electrodes 60A, 60B, 60C, 60D covering the end faces 10a, 10b instead of the paired conductors 40, and stray capacitance may occur between the outermost winding 36 and the external terminal electrodes 60A, 60B, 60C, 60D. In this embodiment, since the length h1 of the outer surface 36a of the winding 36 is shorter than the length h2 of the inner surface 36b, for example, the area of ​​contact between the outermost winding 36 and the external terminal electrodes 60A, 60B, 60C, 60D can be reduced compared to the case where the outer surface 36a and the inner surface 36b have the same length h2, and stray capacitance between the outermost winding 36 and the external terminal electrodes 60A, 60B, 60C, 60D can be reduced. In this case, the metal magnetic powder-containing resin 12 constituting the base body 10 may be located on the outer surface 36a side of the outermost winding 36 on the main surfaces 20a and 20b of the insulating substrate 20, and the insulators 50A and 50B may be located there.

[0036] The present invention is not necessarily limited to the embodiments described above, and various modifications are possible without departing from its spirit. For example, the coil structure 30 does not necessarily have to have two coils that constitute a double coil structure, and may have only one of the coils, in which case it may have a configuration with only one pair of external terminal electrodes.

[0037] As can be seen from the above description, this specification discloses the following: [Note 1] A base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces, An insulating substrate provided within the aforementioned body, extending parallel to the main surface of the body, and having a first main surface and a second main surface facing the pair of main surfaces of the body, A coil structure having a first coil provided within the aforementioned body, including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion; A first external terminal provided on the first end face and electrically connected to the outer end of the first coil portion and Equipped with, A coil component in which, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the outermost winding of the second coil portion is shorter than the length of the inner surface. [Note 2] The outermost winding of the second coil portion has a first surface that contacts the second main surface of the insulating substrate, and a second surface that faces the first surface in the thickness direction of the insulating substrate. The coil component as described in Appendix 1, wherein the second surface of the outermost winding is inclined with respect to the second main surface. [Note 3] The coil component according to Appendix 1 or 2, further comprising a resin body that fills the gap between the outermost winding of the second coil portion and the first end face on the second main surface. [Note 4] A base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces, An insulating substrate provided within the aforementioned body, extending parallel to the main surface of the body, and having a first main surface and a second main surface facing the pair of main surfaces of the body, A coil structure having a first coil provided within the aforementioned body, including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion; A first external terminal is provided on the first end face and is electrically connected to the outer end of the first coil, A pair of conductors is provided on the second main surface of the insulating substrate, adjacent to the first end surface, and electrically connected to the first external terminal. Equipped with, A coil component in which, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the outermost winding of the second coil portion is shorter than the length of the inner surface. [Note 5] The outermost winding of the second coil portion has a first surface that contacts the second main surface of the insulating substrate, and a second surface that faces the first surface in the thickness direction of the insulating substrate. The coil component described in Appendix 4, wherein the second surface of the outermost winding is inclined with respect to the second main surface. [Note 6] The coil component according to appendix 4 or 5, wherein the coil structure is penetrated through the insulating substrate and further comprises a second through-hole conductor that electrically connects the outer end of the first coil on the first main surface to a pair of conductors on the second main surface. [Note 7] The coil component described in Appendix 6, wherein the second through-hole conductor is spaced apart from the first end face. [Note 8] The coil component according to any one of the appendices 4 to 7, wherein, with respect to the length in the thickness direction of the insulating substrate, the length of the first side surface facing the outer surface of the outer winding of the second coil portion on the side away from the first end face of the pair conductor is shorter than the length of the second side surface on the side closer to the first end face. [Note 9] The coil component according to Appendix 4, further comprising a resin body that fills the gap between the outermost winding of the second coil portion and the pair conductor on the second main surface. [Note 10] A base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces, An insulating substrate provided within the aforementioned body, extending parallel to the main surface of the body, and having a first main surface and a second main surface facing the pair of main surfaces of the body, A coil structure having a first coil provided within the aforementioned body, including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion. Equipped with, At least one of the first coil portion and the second coil portion includes a first winding and a second winding adjacent to the outer circumference of the first winding, A coil component in which, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the first winding is shorter than the length of the inner surface. [Note 11] The first winding has a first surface that is in contact with the first main surface or the second main surface on which the first winding is provided, and a second surface that is opposite to the first surface in the thickness direction of the insulating substrate. The coil component according to Appendix 10, wherein the second surface of the first winding is inclined with respect to the first main surface or the second main surface on which the first winding is provided. [Note 12] The coil component according to any one of the appendices 1 to 11, wherein the coil structure further comprises a second coil having a spiral-shaped third coil portion wound parallel to the first coil portion of the first coil on the first main surface, a spiral-shaped fourth coil portion wound parallel to the second coil portion of the first coil on the second main surface, and a third through-hole conductor that penetrates the insulating substrate and electrically connects the third coil portion and the fourth coil portion. [Note 13] The coil component according to Appendix 12, further comprising a magnetic material located on the outer surface side of the outermost winding of the second coil portion on the second main surface. [Explanation of Symbols]

[0038] 1... Coil component, 10... Base body, 12... Metal magnetic powder-containing resin, 20... Insulating substrate, 30... Coil structure, 31A... First planar coil section, 31B... Second planar coil section, 33A... Third planar coil section, 33B... Fourth planar coil section, 31a, 33a... Outer end, 31b, 33b... Inner end, 32, 34, 35... Through conductor, 36... Winding, 50A, 50B... Insulator, 60A~60D... External terminal electrodes, C1... First coil, C2... Second coil.

Claims

1. A base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces, An insulating substrate provided within the aforementioned body, extending parallel to the main surface of the body, and having a first main surface and a second main surface facing the pair of main surfaces of the body, A coil structure having a first coil provided within the element, including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion, A first external terminal provided on the first end face and electrically connected to the outer end of the first coil portion, Equipped with, A coil component in which, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the outermost winding of the second coil portion is shorter than the length of the inner surface.

2. The outermost winding of the second coil portion has a first surface that contacts the second main surface of the insulating substrate, and a second surface that faces the first surface in the thickness direction of the insulating substrate. The coil component according to claim 1, wherein the second surface of the outermost winding is inclined with respect to the second main surface.

3. The coil component according to claim 1, further comprising a resin body that fills the gap between the outermost winding of the second coil portion and the first end face on the second main surface.

4. A base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces, An insulating substrate provided within the aforementioned body, extending parallel to the main surface of the body, and having a first main surface and a second main surface facing the pair of main surfaces of the body, A coil structure having a first coil provided within the element, including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion, A first external terminal is provided on the first end face and is electrically connected to the outer end of the first coil, A pair of conductors is provided on the second main surface of the insulating substrate, adjacent to the first end surface, and electrically connected to the first external terminal. Equipped with, A coil component in which, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the outermost winding of the second coil portion is shorter than the length of the inner surface.

5. The outermost winding of the second coil portion has a first surface that contacts the second main surface of the insulating substrate, and a second surface that faces the first surface in the thickness direction of the insulating substrate. The coil component according to claim 4, wherein the second surface of the outermost winding is inclined with respect to the second main surface.

6. The coil component according to claim 4, wherein the coil structure is penetrated through the insulating substrate and further comprises a second through-hole conductor that electrically connects the outer end of the first coil on the first main surface to a pair of conductors on the second main surface.

7. The coil component according to claim 6, wherein the second through-hole conductor is spaced apart from the first end face.

8. The coil component according to claim 4, wherein, with respect to the length in the thickness direction of the insulating substrate, the length of the first side surface facing the outer surface of the outer winding of the second coil portion on the side away from the first end face of the pair conductor is shorter than the length of the second side surface on the side closer to the first end face.

9. The coil component according to claim 4, further comprising a resin body that fills the gap between the outermost winding of the second coil portion and the pair conductor on the second main surface.

10. A base body having a pair of opposing main surfaces and a first end surface and a second end surface connecting the pair of main surfaces, An insulating substrate provided within the aforementioned body, extending parallel to the main surface of the body, and having a first main surface and a second main surface facing the pair of main surfaces of the body, A coil structure having a first coil provided within the aforementioned body, including a spiral-shaped first coil portion provided on the first main surface of the insulating substrate, a spiral-shaped second coil portion provided on the second main surface of the insulating substrate, and a first through-hole conductor that penetrates the insulating substrate and electrically connects the first coil portion and the second coil portion. Equipped with, At least one of the first coil portion and the second coil portion includes a first winding and a second winding adjacent to the outer circumference of the first winding, A coil component in which, with respect to the length in the thickness direction of the insulating substrate, the length of the outer surface of the first winding is shorter than the length of the inner surface.

11. The first winding has a first surface that is in contact with the first main surface or the second main surface on which the first winding is provided, and a second surface that is opposite the first surface in the thickness direction of the insulating substrate. The coil component according to claim 10, wherein the second surface of the first winding is inclined with respect to the first main surface or the second main surface on which the first winding is provided.

12. The coil component according to any one of claims 1, 4, or 10, wherein the coil structure further comprises a second coil having a spiral-shaped third coil portion wound parallel to the first coil portion of the first coil on the first main surface, a spiral-shaped fourth coil portion wound parallel to the second coil portion of the first coil on the second main surface, and a third through-hole conductor that penetrates the insulating substrate and electrically connects the third coil portion and the fourth coil portion.

13. The coil component according to claim 12, further comprising a magnetic material located on the outer surface side of the outermost winding of the second coil portion on the second main surface.

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