Coil components

Abstract

By overlapping the protrusions of the first insulator and the protrusions of the second insulator via the protrusions of the substrate, the DC superposition characteristics of the coil component are improved.

Description

Technical Field

[0001] The present disclosure relates to coil components. Background Art

[0002] Currently, coil components such as surface-mount planar coil elements are widely used in electrical equipment, including consumer and industrial devices. In particular, the increasing practicality of small portable devices requires multiple voltages from a single power supply to drive various components. Therefore, surface-mount planar coil elements are also used in these power supply applications.

[0003] Such a coil component is disclosed, for example, in Patent Document 1 below. The coil component disclosed in this document has planar spiral coils disposed on the front and back surfaces of a non-magnetic substrate, respectively, and the planar coils are connected to each other by through-hole conductors disposed in the magnetic core portion of the planar coil so as to penetrate the substrate. In addition, in the coil component disclosed in Patent Document 1, an insulator is disposed in the same layer as the layer in which the planar coil is formed, and insulation is achieved between the planar coil and the insulating or winding portion of the coating resin by the insulator. Furthermore, in the coil component disclosed in Patent Document 1, a portion of the non-magnetic substrate is exposed on the side surface of the element body.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-47938 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The inventors have conducted numerous studies on the exposure method on the side surfaces of the element body and have discovered a new technology that can improve the DC superposition characteristics by changing the exposure method on the side surfaces of the element body.

[0009] An object of the present disclosure is to provide a coil component that improves DC superposition characteristics.

[0010] Technical solutions to solve problems

[0011] The coil component involved in one embodiment of the present invention comprises: a body, which contains a magnetic material and has an upper surface and a lower surface parallel to each other; a substrate, which is arranged in the body and extends parallel to the upper surface and the lower surface; a first coil body, which is arranged in the body and formed on the upper surface of the substrate, and has a first planar coil and a first insulator, wherein the first planar coil has a first connection end, a first lead-out end, and a first winding portion connecting the first connection end and the first lead-out end, and the first insulator covers the first planar coil in the same layer as the layer in which the first planar coil is formed; a second coil body, which is arranged in the body and formed on the lower surface of the substrate, and has a second planar coil and a second insulator, wherein the second planar coil has a first winding portion connected to the first planar coil via the substrate. A second connecting end portion connected to the connecting end portion, a second lead-out end portion, and a second winding portion connecting the second connecting end portion and the second lead-out end portion, a second insulator covering the second planar coil in the same layer as the layer on which the second planar coil is formed; and a pair of terminal electrodes, which are arranged on the surface of the element body and are respectively connected to the first lead-out end portion of the first planar coil and the second lead-out end portion of the second planar coil, the substrate having a substrate exposed portion exposed from a first side surface connecting the upper surface and the lower surface of the element body, the first insulator having a first insulator exposed portion exposed from the first side surface of the element body and overlapping with the substrate exposed portion on the first side surface, and the second insulator having a second insulator exposed portion exposed from the first side surface of the element body and overlapping with the first insulator exposed portion on the first side surface across the substrate exposed portion.

[0012] The inventors have newly discovered that when the first insulator exposed portion and the second insulator exposed portion that overlap with the substrate exposed portion are exposed on the side surface of the element body, the DC superposition characteristics of the coil component are improved.

[0013] In the coil component involved in other embodiments, the first coil body has a seed pattern (Seed pattern) formed on the upper surface of the substrate, and a plating portion plated and grown on the seed pattern, and the seed pattern of the first coil body is exposed from the first side surface of the element body between the substrate exposed portion and the first insulator exposed portion.

[0014] In the coil component involved in other embodiments, the second coil body has a seed pattern formed on the upper surface of the substrate and a plating portion grown by plating on the seed pattern, and the seed pattern of the second coil body is exposed from the first side surface of the element body between the substrate exposed portion and the second insulator exposed portion.

[0015] In the coil component according to another embodiment, the substrate exposed portion, the first insulator exposed portion, and the second insulator exposed portion are exposed at a position where the distance between the first side surface and the first coil is shortest.

[0016] In the coil component involved in other embodiments, the element has a second side surface opposite to the first side surface, and in the relative directions of the first side surface and the second side surface, the substrate exposed portion, the first insulator exposed portion and the second insulator exposed portion are exposed on the second side surface at a position corresponding to the position where the substrate exposed portion, the first insulator exposed portion and the second insulator exposed portion of the first side surface are exposed.

[0017] Effects of the Invention

[0018] According to the present disclosure, a coil component is provided that achieves improvement in DC superposition characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic perspective view showing a coil component according to one embodiment.

[0020] Figure 2 Yes Figure 1 The diagram shows the internal structure of the coil component element body.

[0021] Figure 3 Yes Figure 1 A top view of the substrate of the coil component is shown.

[0022] Figure 4 It is a plan view showing the first coil body provided on the upper surface of the substrate.

[0023] Figure 5 It is a plan view showing the second coil body provided on the lower surface of the substrate.

[0024] Figure 6 yes Figure 1 The VI-VI cross-sectional view of the element body is shown.

[0025] Figure 7 Yes Figure 1 The figure shows the exposure state on the side surface of the element body of the coil component.

[0026] Figure 8 It is a figure which shows the exposure method of a conventional technique.

[0027] Figure 9 Is to express Figure 7 Different exposure methods. DETAILED DESCRIPTION

[0028] Hereinafter, various embodiments and examples will be described with reference to the accompanying drawings. In addition, the same or corresponding parts in each drawing are marked with the same reference numerals, and overlapping descriptions are omitted.

[0029] like Figure 1As shown, the coil component 1 of the embodiment has a rectangular parallelepiped shape. As an example, the coil component 1 can be designed with a long side of 1.2 mm, a short side of 1.0 mm, and a height of 0.5 mm. Alternatively, as another example, the coil component 1 can be designed with a long side of 2.0 mm, a short side of 1.2 mm, and a height of 0.6 mm.

[0030] The coil component 1 includes a pair of terminal electrodes 5A and 5B, an element body 10 , and a coil portion 20 embedded in the element body 10 .

[0031] The element body 10 has a rectangular parallelepiped shape and has six faces 10a to 10f. Of the faces 10a to 10f, the top face 10a and the bottom face 10b are parallel to each other, the end faces 10c and 10d are parallel to each other, and the side faces 10e and 10f are parallel to each other. A pair of terminal electrodes 5A and 5B are provided on the end faces 10c and 10d of the element body 10, respectively.

[0032] The element body 10 is made of a magnetic material. In the present embodiment, the element body 10 is made of a resin containing metal magnetic powder as a type of magnetic material. The resin containing metal magnetic powder is a bonding powder in which metal magnetic powder is bonded by a binder resin. The metal magnetic powder can be composed of, for example, iron-nickel alloy (Permalloy), carbonyl iron, amorphous, amorphous or crystalline FeSiCr alloy, aluminum silicon sendower, etc. The binder resin is, for example, a thermosetting epoxy resin. In the present embodiment, the content of the metal magnetic powder in the bonding powder is 80 to 92 vol% by volume and 95 to 99 wt% by mass. From the perspective of magnetic properties, the content of the metal magnetic powder in the bonding powder is 85 to 92 vol% by volume and 97 to 99 wt% by mass.

[0033] The coil portion 20 is composed of a first coil body 30, a substrate 40, and a second coil body 50. Specifically, the first coil body 30 is provided on the upper surface 40a of the substrate 40 located on the upper surface side of the element body 10, and the second coil body 50 is provided on the lower surface 40b of the substrate 40 located on the lower surface side of the element body 10. In this embodiment, the pattern shape of the first coil body 30 observed from the upper surface 40a of the substrate 40 is the same as the pattern shape of the second coil body 50 observed from the lower surface 40b of the substrate 40.

[0034] The substrate 40 is a plate-shaped member extending parallel to the upper surface 10a and the lower surface 10b of the element body 10. Figure 3As shown, the substrate 40 includes an elliptical ring-shaped coil-forming portion 41 extending along the longitudinal direction of the element body 10, a pair of protrusions 46A and 46B (exposed substrate portions) extending from the coil-forming portion 41 to the side surfaces 10e and 10f of the element body 10, respectively, and exposed from the side surfaces 10e and 10f, respectively; and a pair of frame portions 47A and 47B extending along the lateral direction of the element body 10 and sandwiching the coil-forming portion 41 from both sides. Furthermore, a circular through-hole 45 is provided at the edge of the oblong opening 42 in the coil-forming portion 41. A through-hole conductor is filled in the through-hole 45 to electrically connect the inner end 32b of the first planar coil 32 and the inner end 52b of the second planar coil 52, described later.

[0035] The substrate 40 can be made of glass cloth impregnated with cyanate resin (BT (bismaleimide triazine) resin: a registered trademark), with a thickness of 60 μm. In addition to BT resin, polyimide, aramid, etc. can also be used. Ceramics or glass can also be used as the material of the substrate 40. The material of the substrate 40 can be a mass-produced printed circuit board material or a resin material used for BT printed circuit boards, FR4 printed circuit boards, or FR5 printed circuit boards.

[0036] The first coil body 30 is provided on the upper surface 40a of the substrate of the coil forming portion 41. Figure 4 As shown, the first coil body 30 includes a first planar coil 32 constituting a portion of the coil 22 of the coil component 1 and a first insulator 34 .

[0037] The first planar coil 32 is a generally oblong spiral air-core coil wound around the opening 42 of the coil forming portion 41 on the upper surface 40a of the substrate 40 within the same layer. The number of turns of the first planar coil 32 can be one or multiple turns. In this embodiment, the number of turns of the first planar coil 32 is 3 to 4. The first planar coil 32 has an outer end 32a (first lead-out end), an inner end 32b (first connection end), and a first winding portion 32c connecting the outer end 32a and the inner end 32b. The outer end 32a is arranged to be exposed from the end surface 10c of the element body 10 and connected to the terminal electrode 5A. When viewed in the thickness direction of the substrate 40, the inner end 32b is arranged in the area covering the through-hole 45 of the substrate 40 and has a circular shape. The first planar coil 32 is made of, for example, Cu and can be formed by electrolytic plating.

[0038] The first insulator 34 is a thick-film resist patterned using conventional photolithography and disposed on the upper surface 40a of the substrate 40. The first insulator 34 defines the growth area of ​​the first planar coil 32 and covers the first planar coil 32 within the same layer as the first planar coil 32. In this embodiment, the first insulator 34 includes an outer wall 34a and an inner wall 34b that define the outline of the first planar coil 32, and a partition wall 34c that separates the inner and outer turns of the first winding portion 32c of the first planar coil 32. The first insulator 34 is made of, for example, epoxy resin.

[0039] The first insulator 34 further includes a pair of protrusions 36A and 36B. Each protrusion 36A and 36B extends so as to overlap with the protrusions 46A and 46B of the substrate 40 and is exposed from the side surfaces 10e and 10f of the element body 10, respectively. In this embodiment, the cross-sectional shape and end surface shape of the protrusions 36A and 36B perpendicular to the extension direction are rectangular.

[0040] The first planar coil 32 is formed by plating growth in a growth region defined by the first insulator 34. The first planar coil 32 includes a seed pattern 32d patterned on the upper surface 40a of the substrate 40 and a plated portion 32e grown on the seed pattern 32d.

[0041] like Figure 5 As shown, the first coil body 30 further includes a protective film 38 that integrally covers the first planar coil 32 and the first insulator 34 from the upper surface 10a side of the element body 10. The protective film 38 is made of, for example, epoxy resin. The protective film 38 improves the insulation between the metal magnetic powder contained in the element body 10 and the first planar coil 32.

[0042] The second coil body 50 is provided on the lower surface 40b of the substrate of the coil forming portion 41. Figure 5 As shown, the second coil body 50 includes a second planar coil 52 constituting a portion of the coil 22 of the coil component 1 and a second insulator 54 .

[0043] The second planar coil 52 is a roughly oblong spiral air-core coil wound around the opening 42 of the coil forming portion 41 on the lower surface 40b of the substrate 40, within the same layer. The number of turns of the second planar coil 52 can be one or multiple turns. In this embodiment, the number of turns of the second planar coil 52 is 3 to 4. The second planar coil 52 has an outer end 52a (second lead-out end), an inner end 52b (second connection end), and a second winding portion 52c connecting the outer end 52a and the inner end 52b. The outer end 52a is arranged to be exposed from the end surface 10d of the element body 10 and connected to the terminal electrode 5B. When viewed in the thickness direction of the substrate 40, the inner end 52b is arranged in the area covering the through-hole 45 of the substrate 40 and has a circular shape. The second planar coil 52 is made of Cu, for example, and can be formed by electrolytic plating.

[0044] The second insulator 54 is a thick film resist patterned using conventional photolithography and disposed on the lower surface 40b of the substrate 40. The second insulator 54 demarcates the growth area of ​​the second planar coil 52 and covers the second planar coil 52 within the same layer as the layer in which the second planar coil 52 is formed. In this embodiment, the second insulator 54 includes an outer wall 54a and an inner wall 54b that demarcate the outline of the second planar coil 52, and a partition wall 54c that separates the inner and outer turns of the second winding portion 52c of the second planar coil 52. The second insulator 54 is made of, for example, epoxy resin.

[0045] The second insulator 54 further includes a pair of protrusions 56A and 56D. Each protrusion 56A and 56B extends so as to overlap with the protrusions 46A and 46B of the substrate 40 and is exposed from the side surfaces 10e and 10f of the element body 10, respectively. In this embodiment, the cross-sectional shape and end surface shape of the protrusions 56A and 56D perpendicular to the extension direction are rectangular.

[0046] Like the first planar coil 32, the second planar coil 52 is formed by plating growth in a growth region defined by the second insulator 54. The second planar coil 52 includes a seed pattern 52d patterned on the lower surface 40b of the substrate 40 and a plating portion 52e grown on the seed pattern 52d.

[0047] like Figure 5 As shown, the second coil body 50 further includes a protective film 58 that integrally covers the second planar coil 52 and the second insulator 54 from the lower surface 10b side of the element body 10. The protective film 58 is made of, for example, epoxy resin. The protective film 58 improves the insulation between the metal magnetic powder contained in the element body 10 and the second planar coil 52.

[0048] The first planar coil 32, disposed on the upper surface 40a of the substrate 40, and the second planar coil 52, disposed on the lower surface 40b of the substrate 40, have their respective inner ends 32b and 52b connected to each other via through-hole conductors within through-holes 45 that extend through the thickness of the substrate 40. In this embodiment, the first planar coil 32 and the second planar coil 52 are arranged around the opening 42 of the substrate 40 via these through-hole conductors to form an air-core coil 22. The coil 22 has a coil axis parallel to the thickness direction of the substrate 40 (i.e., the relative direction of the upper surface 10a and the lower surface 10b).

[0049] The first planar coil 32 and the second planar coil 52 are wound so that when a voltage is applied between the two ends of the coil 22 (i.e., the outer end 32a of the first planar coil 32 and the outer end 52a of the second planar coil 52), current flows in the same direction (i.e., the same winding direction when viewing the substrate 40 from the thickness direction). Figure 3 As shown, the winding direction of the first planar coil 32 from the outer end 32a to the inner end 32b is clockwise. Figure 5 As shown, the second planar coil 52 turns clockwise from the inner end 52b to the outer end 52a. Since current flows in the same direction in the first planar coil 32 and the second planar coil 52, the generated magnetic fluxes overlap and reinforce each other.

[0050] As described above, in the coil component 1, the protrusions 46A and 46B of the substrate 40, the protrusions 36A and 36B of the first insulator 34, and the protrusions 56A and 56B of the second insulator 54 are exposed on the side surfaces 10e and 10f of the element body 10, respectively. More specifically, the protrusion 46A (substrate exposed portion) of the substrate 40, the protrusion 36A (first insulator exposed portion) of the first insulator 34, and the protrusion 56A (second insulator exposed portion) of the second insulator 54 are exposed on the side surface 10e (first side surface) of the element body 10, while the protrusion 46B (substrate exposed portion) of the substrate 40, the protrusion 36B (first insulator exposed portion) of the first insulator 34, and the protrusion 56B (second insulator exposed portion) of the second insulator 54 are exposed on the side surface 10f (second side surface) of the element body 10. Figure 7 Although the exposure mode on the side surface 10 e of the element body 10 is shown, the exposure mode on the side surface 10 f of the element body 10 is also the same, and therefore the description thereof is omitted.

[0051] like Figure 7 As shown, the protrusion 36A of the first insulator 34 and the protrusion 56A of the second insulator 54 overlap via the protrusion 46A of the substrate 40. In this embodiment, the protrusion 36A of the first insulator 34 and the protrusion 56A of the second insulator 54 have the same end surface dimensions and overlap entirely via the protrusion 46A of the substrate 40.

[0052] Figure 8 The side exposure of the element body of the prior art is shown in FIG. 3 , where the protrusion 36A of the first insulator 34 and the protrusion 56A of the second insulator 54 are separated and do not completely overlap. The inventors have found that the protrusion 36A of the first insulator 34 and the protrusion 56A of the second insulator 54 are as follows: Figure 8 Furthermore, it was found that it was difficult to achieve high pressure resistance due to the pressure in the thickness direction applied to the protrusion 46A of the substrate 40 in the region between the protrusion 36A of the first insulator 34 and the protrusion 56A of the second insulator 54.

[0053] In the coil component 1, as Figure 7 As shown, the DC superposition characteristics are improved by overlapping the protrusion 36A of the first insulator 34 and the protrusion 56A of the second insulator 54 via the protrusion 46A of the substrate 40. The protrusion 36A of the first insulator 34 and the protrusion 56A of the second insulator 54 do not necessarily need to completely overlap, and may partially overlap.

[0054] In the coil component 1 , also on the side surface 10 f opposite to the side surface 10 e , the protrusion 36B of the first insulator 34 and the protrusion 56B of the second insulator 54 overlap via the protrusion 46B of the substrate 40 at a position corresponding to the side surface 10 e .

[0055] In coil component 1, first planar coil 32 and second planar coil 52 have an elliptical shape. The first planar coil 32 and second planar coil 52 are located at the center of side surfaces 10e and 10f of element body 10, where their distance from side surfaces 10e and 10f is shortest. This portion of the coil has a low magnetic volume within element body 10 and is prone to magnetic flux saturation. Therefore, arranging protrusion 36A of first insulator 34, protrusion 56A of second insulator 54, and protrusion 46A of substrate 40 at this location can more effectively improve DC superposition characteristics.

[0056] In addition, if Figure 9 As shown, the seed pattern 32d of the first planar coil 32 and the seed pattern 52d of the second planar coil 52 may be extended to the side surfaces 10e and 10f of the element body, and exposed from the side surfaces 10e and 10f of the element body 10. Either the seed pattern 32d of the first planar coil 32 or the seed pattern 52d of the second planar coil 52 may be exposed from the side surfaces 10e and 10f of the element body 10.

Claims

1. A coil component, wherein: have: A body comprising a magnetic material and having an upper surface and a lower surface parallel to each other; a substrate disposed within the body and extending parallel to the upper and lower surfaces; a first coil body disposed within the element body and formed on the upper surface of the substrate, comprising a first planar coil and a first insulator, wherein the first planar coil has a first connecting end portion, a first lead-out end portion, and a first winding portion connecting the first connecting end portion and the first lead-out end portion, and the first insulator covers the first planar coil in the same layer as the layer in which the first planar coil is formed; a second coil body disposed within the element body and formed on a lower surface of the substrate, comprising a second planar coil and a second insulator, wherein the second planar coil comprises a second connecting end portion connected to the first connecting end portion of the first planar coil via the substrate, a second lead-out end portion, and a second winding portion connecting the second connecting end portion and the second lead-out end portion, and the second insulator covering the second planar coil in the same layer as the layer in which the second planar coil is formed; and a pair of terminal electrodes provided on the surface of the element body and connected to the first lead-out end portion of the first planar coil and the second lead-out end portion of the second planar coil, respectively; The substrate has a substrate exposed portion exposed from a first side surface connecting the upper surface and the lower surface of the element body. The first insulator has a first insulator exposed portion exposed from the first side surface of the element body and overlapping with the substrate exposed portion on the first side surface. The second insulator includes a second insulator exposed portion that is exposed from the first side surface of the element body and overlaps with the first insulator exposed portion on the first side surface with the substrate exposed portion interposed therebetween.

2. The coil component according to claim 1, wherein The first coil body includes a seed pattern formed on the upper surface of the substrate and a plated portion grown by plating on the seed pattern. The seed pattern of the first coil body is exposed from the first side surface of the element body between the substrate exposed portion and the first insulator exposed portion.

3. The coil component according to claim 1, wherein The second coil body includes a seed pattern formed on the upper surface of the substrate and a plated portion grown by plating on the seed pattern. The seed pattern of the second coil body is exposed from the first side surface of the element body between the substrate exposed portion and the second insulator exposed portion. The coil component according to claim 2 , wherein: The second coil body includes a seed pattern formed on the upper surface of the substrate and a plated portion grown by plating on the seed pattern. The seed pattern of the second coil body is exposed from the first side surface of the element body between the substrate exposed portion and the second insulator exposed portion.

5. The coil component according to any one of claims 1 to 4, wherein The substrate exposed portion, the first insulator exposed portion, and the second insulator exposed portion are exposed at a position where the distance between the first side surface and the first coil is shortest.

6. The coil component according to any one of claims 1 to 4, wherein The element body has a second side surface opposite to the first side surface, and in the relative direction of the first side surface and the second side surface, the substrate exposed portion, the first insulator exposed portion and the second insulator exposed portion are exposed on the second side surface at a position corresponding to the position where the substrate exposed portion, the first insulator exposed portion and the second insulator exposed portion of the first side surface are exposed.

7. The coil component according to claim 5, wherein The element body has a second side surface opposite to the first side surface, and in the relative direction of the first side surface and the second side surface, the substrate exposed portion, the first insulator exposed portion and the second insulator exposed portion are exposed on the second side surface at a position corresponding to the position where the substrate exposed portion, the first insulator exposed portion and the second insulator exposed portion of the first side surface are exposed.

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