JP6113510B2 - Magnetic element - Google Patents

Description

  The present invention relates to a magnetic element in which coils provided on the front and back surfaces of an insulating base material are electrically connected through contact holes provided in the insulating base material.

  The following patent document discloses a magnetic element having an insulating base, a coil, and a magnetic body. The coils provided on the front surface side and the back surface side of the insulating base material are electrically connected via first contact holes provided in the insulating base material. In addition to the first contact hole, the insulating base material is provided with a second contact hole, and a magnetic material is provided in the second contact hole.

  As shown in the patent document, providing a contact hole in an insulating base material, embedding a magnetic material therein, and winding a planar coil around the surface of the insulating base material around the magnetic material is intended to improve inductance. In addition, it is preferable.

  However, in the patent document, the first contact hole is provided in the insulating base material, and the coils on the front and back surfaces of the insulating base material are electrically connected to each other, and the magnetism is provided in the second contact hole provided separately from the first contact hole. Since the body is embedded, there is a problem that the magnetic element is enlarged.

Japanese Utility Model Publication No. 5-90929 JP 2010-80550 A JP 2009-278209 A

  Therefore, the present invention is to solve the above-described conventional problems, and in particular, an object of the present invention is to provide a magnetic element that can obtain a high inductance and can promote downsizing.

The magnetic element in the present invention is
An insulating base material, a first coil formed on the upper surface of the insulating base material, a second coil formed on the lower surface of the insulating base material, a winding start position located inside the first coil, and A conductive layer electrically connecting between the winding start ends located inside the second coil,
A through hole is formed in the insulating substrate, the conductive layer is formed on the entire side wall of the through hole, and a first magnetic body is provided inside the conductive layer, and the first magnetic body is provided. Is characterized in that the through hole is filled in direct contact with the conductive layer over the entire circumference of the through hole . As described above, in the present invention, since the conductive layer and the first magnetic body are provided in the same through hole, the magnetic flux can easily pass through the central portion of each coil in the thickness direction of the insulating base material, and high inductance can be obtained. At the same time, miniaturization of the magnetic element can be promoted.

In addition, since the conductive layer is a portion connected to the winding start end of each coil , even if the conductive layer is in direct contact with the electrically conductive first magnetic body, the characteristics such as inductance are not deteriorated. In addition, downsizing can be more effectively promoted.

  In the present invention, a second magnetic body is provided so as to overlap with the first coil side, and a third magnetic body is provided so as to overlap with the second coil side, and the first magnetic body and the first magnetic body are provided. A magnetic path is preferably formed between the second magnetic body and the third magnetic body. A magnetic path can be formed between the first magnetic body, the second magnetic body, and the third magnetic body, leakage flux is reduced, and inductance can be improved more effectively.

  Further, the second magnetic body and the third magnetic body are provided to the outside of the side portion of the insulating base material, and the second magnetic body and the third magnetic body It is also possible to adopt a configuration in which a magnetic path is formed outside the side portion. Thereby, an inductance can be raised more effectively.

  In the present invention, the first magnetic body may be formed of a magnetic material different from that of the second magnetic body and the third magnetic body. At this time, the magnetic material constituting the first magnetic body has a higher saturation magnetic flux density or higher magnetic permeability or a higher saturation magnetic flux density than the magnetic materials constituting the second magnetic body and the third magnetic body. And having a high magnetic permeability. Thereby, a high inductance can be obtained more effectively.

In the present invention, the first extraction electrode is electrically connected to the winding end located outside the first coil, and the second extraction electrode is electrically connected to the winding termination located outside the second coil. Connected,
An outer magnetic body is provided in an area outside the first coil and the second coil and in which the first extraction electrode and the second extraction electrode are not formed, and the outer magnetic It is preferable that a magnetic path is formed between the body and the second magnetic body and the third magnetic body. Thereby, a closed magnetic circuit can be formed around each coil, leakage magnetic flux can be more effectively suppressed, and inductance can be effectively increased.

  Further, in the present invention, the first region is located in any one of a left region, a right region, a front region, and a rear region located outside the first coil and the second coil in a plan view. It is preferable that an extraction electrode is provided, the second extraction electrode is provided in any one of the remaining three regions, and the outer magnetic body is provided in each of the remaining two regions. Space can be used effectively and the outer magnetic body can be formed appropriately.

  In the present invention, the first extraction electrode and the second extraction electrode are provided in the left region and the right region, and the outer magnetic body is provided in the front region and the rear region. Is preferred. Closed magnetic paths can be formed in front and rear as viewed from the center of each coil, and inductance can be effectively increased.

  In the present invention, the inter-turn-turn magnetic material is provided at least partially between the coil turns of the first coil and the second coil in a state of being electrically insulated from the coil turns. Is preferred. Thereby, magnetic flux leakage can be suppressed more effectively and higher inductance can be obtained.

  In the present invention, the inter-coil turn magnetic body is preferably made of an electrically insulating magnetic material. Accordingly, the magnetic material between the coil turns and the coil turn can be electrically insulated from each other without increasing the interval between the coil turns.

  According to the present invention, high inductance can be obtained, and downsizing of the magnetic element can be promoted.

FIG. 1A is a plan view of the thin inductor according to the first embodiment, and in particular, a plan view of the first coil provided on the insulating base and the upper surface portion of the extraction electrode. (B) is a top view of the lower surface part of the 2nd coil and extraction electrode which are provided under an insulating base material. 2A is a vertical cross-sectional view of the thin inductor taken along the line AA shown in FIG. 1A and viewed from the direction of the arrow, and FIG. 2B is a cross-sectional view of B shown in FIG. FIG. 2C is a longitudinal sectional view of the thin inductor cut from the line -B and viewed from the direction of the arrow, and FIG. 2C shows a modification of FIG. FIG. 3A is a plan view of the thin inductor according to the second embodiment, and FIG. 3C is a cross-sectional view of the thin inductor taken along the line CC shown in FIG. FIG. 3C is a longitudinal sectional view, and FIG. 3C is a plan view of the lower surface portion of the second coil and the extraction electrode provided under the insulating base material. 4A is a plan view of the thin inductor according to the third embodiment, and FIG. 4C is a cross-sectional view of the thin inductor as viewed from the direction of the arrow cut along the line DD shown in FIG. FIG. 4C is a longitudinal sectional view, and FIG. 4C is a plan view of the lower surface portion of the second coil and the extraction electrode provided under the insulating base material. FIG. 5 shows a modification of FIG.

  FIG. 1A is a plan view of the thin inductor according to the first embodiment, and in particular, a plan view of the first coil provided on the insulating base and the upper surface portion of the extraction electrode. (B) is a top view of the lower surface part of the 2nd coil and extraction electrode which are provided under an insulating base material. In FIGS. 1A and 1B, the magnetic sheets 21 and 22 are omitted. FIG. 2A is a longitudinal sectional view of a thin inductor taken along the line AA shown in FIG. 1A and viewed from the direction of the arrow, and FIG. 2B is shown in FIG. It is the longitudinal cross-sectional view of the thin inductor cut | disconnected from the BB line | wire shown and seen from the arrow direction, FIG.2 (c) shows the modification of FIG.2 (b).

  As shown in FIGS. 2A and 2B, the thin inductor (magnetic element) 10 includes an insulating base 11, a first coil 12, a second coil 13, a conductive layer 14, and a first extraction. An electrode 15, a second extraction electrode 16, a central magnetic body (first magnetic body) 20, and magnetic sheets (second magnetic body and third magnetic body) 21 and 22 are configured. Is done.

  Although the material of the insulating base material 11 is not specifically limited, It is suitable that it is a glass epoxy board | substrate combining the copper foil (foil body) which comprises each coil 12 and 13 mentioned later.

  In FIG. 1A, the plane of the insulating base 11 is a square or a rectangle, but the shape is not limited.

  As shown in FIGS. 1A and 2A, the first coil 12 is formed on the upper surface 11 a of the insulating substrate 11. Further, as shown in FIGS. 1C and 2A, the second coil 13 is formed on the lower surface 11 b of the insulating base material 11.

  As shown in FIG. 1 (a), the first coil 12 is a planar coil wound while being bent at a right angle from the inner winding start end 12a to the outer winding end 12b.

  Further, as shown in FIG. 1B, the second coil 13 is a planar coil wound while being bent at a right angle from the inner winding start end 13a to the outer winding end 13b.

  As shown in FIGS. 1 and 2, a through hole 25 penetrating from the upper surface 11 a to the lower surface 11 b is formed in the approximate center of the insulating base material 11. 1A and 1B, the side wall 25a of the through hole 25 is indicated by a dotted line.

  In FIG. 1, the planar shape of the through hole 25 is a square shape, but the shape is not limited and may be a circular shape or the like. Further, the through hole 25 can be formed in the insulating base material 11 by drilling or laser processing, or by die processing in which a portion corresponding to the through hole 25 of the insulating substrate 11 is removed by a die.

  As shown in FIGS. 1A and 1B, the conductive layer 14 is formed along the side wall 25 a of the through hole 25. The conductive layer 14 is integrally connected to the winding start end 12 a of the first coil 12 and the winding start end 13 a of the second coil 13, respectively. Therefore, the first coil 12 and the second coil 13 are electrically connected via the conductive layer 14.

  As shown in FIGS. 1 and 2, the conductive layer 14 is formed around the through hole 25 and does not completely fill the through hole 25. Therefore, the conductive layer 14 has a quadrangular ring shape (hollow shape) formed along the side wall 25 a of the through hole 25.

  As shown in FIGS. 1A and 1B, the conductive layer 14 has a rectangular outer shape in which a part of the conductive layer 14 protrudes not only to the side wall 25 a of the through hole 25 but also to the upper surface 11 a and the lower surface 11 b of the insulating substrate 11. It is composed. However, if the through hole 25 is circular, the outer shape of the conductive layer 14 can also be circular. As shown in FIGS. 1A and 1B, the conductive layer 14 is connected to the first coil 12 and the second coil 13 only at the positions of the winding start ends 12a and 13a. It is not in contact with the coil turns 12c, 13c located inside.

  As shown in FIGS. 1A and 1B and FIGS. 2A and 2B, a central magnetic body (first magnetic body) 20 is formed in the same through hole 25 as the through hole 25 in which the conductive layer 14 is formed. Is embedded. The central magnetic body 20 fills the through hole 25 existing inside the conductive layer 14.

  Thus, the through hole 25 is filled with the conductive layer 14 and the central magnetic body 20. The through hole 25 may not be completely filled with the conductive layer 14 and the central magnetic body 20, but the inductance is effectively improved by completely filling the space other than the conductive layer 14 with the central magnetic body 20. This is preferable.

  In the embodiment shown in FIGS. 1 and 2, the conductive layer 14 and the central magnetic body 20 are in direct contact with each other. For example, an insulating layer may be interposed between the conductive layer 14 and the central magnetic body 20 to electrically insulate the conductive layer 14 and the central magnetic body 20 from each other. 13 is connected to the winding start ends 12a and 13a. Therefore, even if the conductive layer 14 and the conductive central magnetic body 20 are in direct contact with each other, characteristics such as inductance are not deteriorated. Since the conductive layer 14 and the central magnetic body 20 can be formed in contact with each other as described above, it is not necessary to insert the above-described insulating layer or the like into the through hole 25, and the conductive layer 14 and the central magnetic body 20 can be easily formed in the through hole 25. And can reduce the size of the thin inductor 10 effectively.

  As described above, since the conductive layer 14 and the central magnetic body 20 may be conductive, the central magnetic body 20 can be formed of a conductive magnetic material.

  The central magnetic body 20 can be made of the same magnetic material as the magnetic sheets 21 and 22, or can be made of a different magnetic material. When the central magnetic body 20 is formed of a magnetic material different from the magnetic sheets 21 and 22, the magnetic material having a higher magnetic permeability μ or higher saturation magnetic flux density Bs than the magnetic sheets 21 and 22, or a higher magnetic permeability μ and high saturation. By forming the central magnetic body 20 using a magnetic material having a magnetic flux density Bs, the inductance can be increased more effectively.

  As shown in FIG. 2A, the first extraction electrode 15 is formed on the left side surface (X1 side surface) 11 d side of the insulating base material 11. Further, as shown in FIG. 2A, the second extraction electrode 16 is formed on the right side surface (X2 side surface) 11 e side of the insulating base material 11.

  As shown in FIG. 1A, the first extraction electrode 15 is connected to the winding end 12 b of the first coil 12. Further, as shown in FIG. 1B, the second extraction electrode 16 is connected to the winding end 13 b of the second coil 13.

  Each of the first coil 12 and the second coil 13 is a spiral as shown in FIGS. 1A and 1B, for example, foil bodies (for example, copper foils) formed on the upper surface 11a and the lower surface 11b of the insulating base material 11, respectively. It is formed in a laminated structure of a conductor formed by a technique such as etching and a plating layer formed by electrolytic plating or the like on the surface of this conductor.

  Further, the first extraction electrode 15 and the second extraction electrode 16 located on the upper surface 11 a and the lower surface 11 b of the insulating base material 11 are also formed in a laminated structure of a foil body and a plating layer, like the coils 12 and 13. Moreover, the part of the extraction electrodes 15 and 16 located in the side surfaces 11d and 11e of the insulating base material 11 is formed with a plating layer.

  The conductive layer 14 is formed of a plating layer that constitutes the coils 12 and 13 continuously with the first coil 12 and the second coil 13.

  However, the layer structures of the coils 12, 13, the conductive layer 14, and the extraction electrodes 15, 16 are not particularly limited.

  As shown in FIG. 2A, thin solder lands 34 are formed on the outermost surfaces of the first extraction electrode 15 and the second extraction electrode 16. The solder land 34 is, for example, a Ni / Au layer (Ni is the base side), a Ni / Sn layer, a Ni / solder layer, or a Ni / Ag layer.

  As shown in FIG. 2A, the first magnetic sheet 21 is disposed on the upper surface of the first coil 12 via an insulating layer (adhesive layer) 31. Further, as shown in FIG. 2A, the second magnetic sheet 22 is disposed on the lower surface of the second coil 13 via an insulating layer (adhesive layer) 32.

  In the present embodiment, a magnetic path is formed between the central magnetic body 20 and the magnetic sheets 21 and 22. Even if the insulating layers 31 and 32 are interposed between the central magnetic body 20 and the magnetic sheets 21 and 22, there is no problem as long as a magnetic path is formed. In addition, it can also comprise so that the center magnetic body 20 and the magnetic layer which comprises each magnetic sheet 21 and 22 may contact | connect.

The configuration of the magnetic sheets 21 and 22 is not particularly limited. Polyethylene naphthalate, polyethylene terephthalate, FeAlN the insulating sheet surface of the polyamide such that the structure magnetic layer such as FeAlO or FeN is formed, on the surface of the insulating sheet, FeAlN, insulating the magnetic layer and the SiO ₂ or the like FeAlO or FeN A configuration in which a predetermined number of layers are alternately laminated, or an existing ferrite sheet or ferrite plate, a sheet-like material obtained by mixing a magnetic alloy ribbon or soft magnetic powder with an insulating resin, and the like can be presented.

  For the insulating layers (adhesive layers) 31 and 32 that join the coils 12 and 13 and the magnetic sheets 21 and 22, for example, an epoxy low temperature curing agent or an acrylic low temperature curing agent can be used.

  As shown in FIG. 1A, the width dimension of the thin inductor 10 is T1, the length dimension is L1, the width dimension of the through hole 25 is T2 (<T1), and the length dimension is L2 (<L1 ). Specifically, the width dimension T1 is 1.0 to 10 mm, the width dimension T2 is 0.1 to 5 mm, the length dimension L1 is 0.5 to 10 mm, and the length dimension L2 is 0.00. 1-5 mm.

  Conventionally, the conductive layer and the magnetic material are formed in separate through holes formed in the insulating base material. For this reason, a region for forming a plurality of through holes has to be secured in the insulating base material, which has been a factor that hinders downsizing of the magnetic element.

  In this embodiment, as shown in FIGS. 1 and 2A and 2B, coils 12 and 13 are provided on the upper and lower surfaces of the insulating base material 11, respectively, and between the winding start ends 12a and 13a of the coils 12 and 13, respectively. The basic configuration is to conduct through the through hole 25 formed in the insulating substrate 11.

  As shown in FIG. 1, the coils 12 and 13 are planar coils, and not only the conductive layer 14 but also the central magnetic body 20 can be appropriately formed in the central region located inside the innermost coil turn 12c. A possible through hole 25 was formed.

  By forming the conductive layer 14 and the central magnetic body 20 in the common through hole 25, the magnetic flux can easily pass through the central portions of the coils 12 and 13 in the thickness direction of the insulating base material 11, and high inductance can be obtained. can get. In addition, since the central magnetic body 20 is formed in the same through-hole 25 using the through-hole 25 for forming the conductive layer 14, it is not necessary to form separate through-holes in the insulating substrate 11, and it is thin. Downsizing of the inductor 10 can be promoted, and the complexity of the manufacturing process can be suppressed.

  The conductive layer 14 is, for example, an electroless plating layer, whereby the conductive layer 14 can be appropriately formed along the side wall 25 a of the through hole 25. At this time, the entire inside of the through hole 25 is not filled with the conductive layer 14, and the center of the through hole 25 is easily left in a penetrating state.

  The central magnetic body 20 is obtained by solidifying and molding magnetic powder and a binder (binder resin), for example. The material of the magnetic powder is not limited, but when the material is different from the magnetic layer constituting the magnetic sheets 21 and 22, the magnetic powder having a high saturation magnetic flux density Bs or high magnetic permeability μ, or the high saturation magnetic flux By using the magnetic powder having the density Bs and the high magnetic permeability μ for the central magnetic body 20, a high inductance can be obtained more effectively. The central magnetic body 20 can be formed by filling the through hole 25 with a slurry having magnetic powder and a binder and solidifying the slurry.

  For example, the central magnetic body 20 can be formed of an electrically insulating magnetic material having a ferrite and a binder resin, but there is no particular problem even if the central magnetic body 20 and the conductive layer 14 are in contact with each other. Conductive magnetic alloy powder is used for the magnetic body 20, and at that time, a high saturation magnetic flux density Bs or a high magnetic permeability μ, or a Fe base such as FeSiB, FePC, or FePCB having a high saturation magnetic flux density Bs and a high magnetic permeability μ. Amorphous alloys, Fe-based nanocrystalline alloys such as FeZrB, FeNbB and FeNbCuSiB, and powders of Fe-based crystalline alloys such as FeNi, FeAlSi and FeSi can be used.

  In the embodiment shown in FIGS. 1 and 2, the conductive layer 14 is formed on all the side walls 25 a of the through hole 25. Therefore, the conductive layer 14 has a shape surrounding the through hole 25. Since the conductive layer 14 is a portion that electrically connects the first coil 12 and the second coil 13 through the through hole 25, the conductive layer 14 is not formed on all the side walls 25a, and the coil 12 is not connected. , 13 can be formed only on a part of the side wall 25a. However, by forming the conductive layer 14 on all the side walls 25a of the through holes 25 as in the present embodiment, the first coil 12 and the second coil 13 can be more reliably connected. is there.

  In the embodiment shown in FIGS. 1 and 2, since the magnetic sheets 21 and 22 forming the magnetic path with the central magnetic body 20 are formed on the coils 12 and 13, the leakage magnetic flux can be reduced, and the inductance and Q The value can be improved. Moreover, the magnetic sheets 21 and 22 can be used as a magnetic shield.

  Further, as shown in FIG. 2C, the front part 21a and the rear part 21b of the first magnetic sheet 21 are formed to extend outward from the front side face 11f and the rear side face 11g of the insulating base material 11, and The front portion 22a and the rear portion 22b of the second magnetic sheet 22 are formed to extend outward from the front side surface 11f and the rear side surface 11g of the insulating base material 11, and each front portion 21a, 22a and each rear portion 21b are formed. , 22b are brought into contact with each other, or the front portions 21a, 22a and the rear portions 21b, 22b are bent in the height direction, and the front portions 21a, 22a and the rear portions 21b, 22b are bonded together. And fix. Thereby, a magnetic path can be formed between the first magnetic sheet 21 and the second magnetic sheet 22 via the front portions 21a and 22a and the rear portions 21b and 22b, and the central magnetic body 20 of the thin inductor 10 is formed. Closed magnetic paths can be formed from the provided position toward the front (Y1) and the rear (Y2), respectively. Therefore, it is possible to improve the inductance more effectively.

  In the embodiment shown in FIGS. 1 and 2, the magnetic sheets 21 and 22 are disposed via the adhesive layer 31 after the central magnetic body 20 is formed in the through hole 25. After the magnetic sheets 21 and 22 are bonded through the adhesive layer 31 without forming the body 20, through holes are formed at locations corresponding to the through holes 25 of the magnetic sheets 21 and 22, and then the through holes 25 are formed. Further, the central magnetic body 20 may be formed in the through holes opened in the magnetic sheets 21 and 22. In this case, through holes are also formed in the magnetic sheets 21 and 22 at positions corresponding to the through holes 25.

FIG. 3A is a plan view of the thin inductor according to the second embodiment, and FIG. 3C is a cross-sectional view of the thin inductor taken along the line CC shown in FIG. FIG. 3C is a longitudinal sectional view, and FIG. 3C is a plan view of the lower surface portion of the second coil and the extraction electrode provided under the insulating base material.
In FIG. 3, the same parts as those in FIGS.

  As shown in FIG. 3, the first extraction electrode 15 electrically connected to the first coil 12 is formed in the left region (region on the X1 side) 11j when viewed from the first coil 12. The second extraction electrode 16 electrically connected to the second coil 13 is formed in the right region (X2 side region) 11k as viewed from the second coil 13.

  Therefore, when viewed from the first coil 12 and the second coil 13, the extraction electrodes 15 and 16 are not formed in the front region (Y1 side region) 11h and the rear region (Y2 side region) 11i.

  As shown in FIG. 3, outer magnetic bodies 26 and 27 are provided in the front region (Y1 side region) 11h and the rear region (Y2 side region) 11i of the coils 12 and 13, respectively.

  For example, as shown in FIGS. 3A and 3C, notches 36 and 37 (dotted line portions are side walls of the notches) are formed in the front region 11 h and the rear region 11 i of the insulating base material 11, and the outer magnetic body 26. , 27 are provided in the notches 36, 37. The outer magnetic bodies 26 and 27 partially extend to the upper surface 11 a and the lower surface 11 b of the insulating base material 11, but are not in contact with the coil turns 12 d and 13 d located on the outermost sides of the coils 12 and 13.

  Magnetic paths are formed between the outer magnetic bodies 26 and 27 and the magnetic sheets 21 and 22. As a result, a closed magnetic path from the central magnetic body 20 to the magnetic sheets 21 and 22 to the outer magnetic bodies 26 and 27 is formed, the leakage magnetic flux can be more effectively suppressed, and the inductance can be further improved.

  If the magnetic path can be formed between the outer magnetic bodies 26 and 27 and the magnetic sheets 21 and 22, there is no particular limitation on how the outer magnetic bodies 26 and 27 are provided on the insulating base material 11. A through hole may be formed in the front region 11h and the rear region 11i of the material 11, and the outer magnetic bodies 26 and 27 may be embedded in each through hole. However, by providing notches 36 and 37 in the insulating base material 11 and embedding the outer magnetic bodies 26 and 27 in the notches 36 and 37, the outer magnetism can be reduced as much as possible while maintaining the miniaturization of the thin inductor 10. The bodies 26 and 27 can be formed larger.

  Further, the outer magnetic bodies 26 and 27 can be formed of a magnetic material having a high saturation magnetic flux density Bs and a high magnetic permeability μ like the central magnetic body 20.

  In the embodiment shown in FIG. 3, out of the left region 11j, the right region 11k, the front region 11h, and the rear region 11i located outside the coils 12 and 13, the extraction electrode is provided in each of the left region 11j and the right region 11k. 15 and 16 are formed, and the outer magnetic bodies 26 and 27 are provided in the remaining front region 11h and rear region 11i. For example, the extraction electrodes 15 and 15 are disposed in the left region 11j and the front region 11h, respectively. 16 and the remaining right region 11k and the rear region 11i are provided with outer magnetic bodies 26 and 27, respectively (in this case, the outer magnetic bodies 26 and 27 may be integrated L-shaped). It is good. However, by adopting the configuration of the embodiment shown in FIG. 3, closed magnetic paths can be formed from the center of the coils 12 and 13 to the front (Y1) and the rear (Y2), respectively, and the inductance can be effectively increased.

  In the present embodiment as well, as in the first embodiment, the magnetic sheets 21 and 22 are formed without the central magnetic body 20 and the outer magnetic bodies 26 and 27 formed in the through holes 25 and the notches 36.37. After bonding through the adhesive layer 31, through holes are formed at locations corresponding to the through holes 25 and the notches 26 and 27 of the magnetic sheets 21 and 22, and then the through holes 25 and the notches 26 and 27 and the respective The central magnetic body 20 and the outer magnetic bodies 26 and 27 may be formed in the through holes opened in the magnetic sheets 21 and 22.

  4A is a plan view of the thin inductor according to the third embodiment, and FIG. 4C is a cross-sectional view of the thin inductor as viewed from the direction of the arrow cut along the line DD shown in FIG. FIG. 4C is a longitudinal sectional view, and FIG. 4C is a plan view of the lower surface portion of the second coil and the extraction electrode provided under the insulating base material.

  In the embodiment shown in FIG. 4, an inter-coil magnetic body 40 is provided between the coil turns constituting the coils 12 and 13. A magnetic body 41 is also provided around the outer sides of the outermost coil turns 12d and 13d. 4A and 4C, the magnetic bodies 40 and 41 are indicated by oblique lines.

  Each of the magnetic bodies 40 and 41 is formed on the upper surface 11a and the lower surface 11b of the insulating base material 11 as with the coils 12 and 13. Each magnetic body 40, 41 is electrically insulated from the coil turn. For example, each of the magnetic bodies 40 and 41 is formed of an electrically insulating magnetic material having ferrite and a binder resin. Thereby, since each magnetic body 40 and 41 and each coil turn can be made into the contact state, it is not necessary to enlarge the space | interval between each coil turn, and size reduction of a thin inductor can be promoted. Each of the magnetic bodies 40 and 41 can be formed by applying a slurry-like magnetic body to the front and back surfaces of the insulating base 11 located between the coil turns or outside the coil, or by sputtering or vapor deposition. is there.

  As shown in FIG. 4, by providing the magnetic bodies 40 and 41, the leakage magnetic flux can be reduced more effectively and a higher inductance can be obtained.

  Further, as shown in FIG. 5, by providing the outer magnetic bodies 26 and 27 shown in FIG. 4 together with the magnetic bodies 40 and 41 in the front region 11h and the rear region 11i, higher inductance can be obtained. The magnetic sheets 21 and 22, the central magnetic body 20, and the outer magnetic bodies 26 and 27 can be formed in the same manner as in the first embodiment and the second embodiment.

  One of the magnetic bodies 40 and 41 shown in FIGS. 4 and 5 may be formed. Further, the inter-coil turn magnetic body 40 does not have to be disposed between all the coil turns, and the inter-coil turn magnetic body 40 may be provided in a part between the coil turns.

DESCRIPTION OF SYMBOLS 10 Thin inductor 11 Insulating base material 11h Front area | region 11i Rear area | region 11j Left area | region 11k Right area | region 12 1st coil 12a, 13a Winding start end 12b, 13b Winding end 12c, 13c, 12d, 13d Coil turn 13 2nd coil 14 Conductive layers 15 and 16 Extraction electrode 20 Central magnetic body (first magnetic body)
21, 22 Magnetic sheet (second magnetic body, third magnetic body)
25 Through-hole 26 Outer magnetic body 40, 41 Magnetic body

Claims (10)

An insulating base material, a first coil formed on the upper surface of the insulating base material, a second coil formed on the lower surface of the insulating base material, a winding start position located inside the first coil, and A conductive layer electrically connecting between the winding start ends located inside the second coil,
A through hole is formed in the insulating substrate, the conductive layer is formed on the entire side wall of the through hole, and a first magnetic body is provided inside the conductive layer, and the first magnetic body is provided. The magnetic element is characterized in that the through hole is filled in direct contact with the conductive layer over the entire circumference of the through hole . A second magnetic body is provided to overlap the first coil side, a third magnetic body is provided to overlap the second coil side, and the first magnetic body, the second magnetic body, and The magnetic element according to claim 1, wherein a magnetic path is formed between the third magnetic body. The second magnetic body and the third magnetic body are provided to the outside of the side portion of the insulating base, and between the second magnetic body and the third magnetic body. The magnetic element according to claim 2 , wherein a magnetic path is formed outside the side portion. Said first magnetic body, second magnetic body and the magnetic element according to claim 2 or 3 formed by the third magnetic body and the different magnetic materials. The magnetic material constituting the first magnetic body has a higher saturation magnetic flux density or higher magnetic permeability, or a higher saturation magnetic flux density and higher permeability than the magnetic materials constituting the second magnetic body and the third magnetic body. The magnetic element according to claim 4, which has a magnetic susceptibility. A first extraction electrode is electrically connected to the winding end located outside the first coil, and a second extraction electrode is electrically connected to the winding end located outside the second coil. And
An outer magnetic body is provided in an area outside the first coil and the second coil and in which the first extraction electrode and the second extraction electrode are not formed, and the outer magnetic body and the second magnetic body and third magnetic element according to any one of claims 2 to 5 magnetic path is formed between the magnetic body. The first extraction electrode is provided in any one of a left region, a right region, a front region, and a rear region located outside the first coil and the second coil in a plan view. 7. The method according to claim 2, wherein the second extraction electrode is provided in any one of the remaining three regions, and the outer magnetic body is provided in each of the remaining two regions. Magnetic element. The magnetism according to claim 7, wherein the first extraction electrode and the second extraction electrode are provided in the left region and the right region, and the outer magnetic body is provided in the front region and the rear region. element. At least a portion between the coil turns magnetic between coil turns of said first coil and said second coil, and the coil turns electrically insulated claims 1 provided in the form of 8 The magnetic element according to any one of claims. The magnetic element according to claim 9 , wherein the inter-coil turn magnetic body is made of an electrically insulating magnetic material.

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