Laminated inductor and laminated inductor array

Abstract

The present invention provides a laminated inductor and a laminated inductor array in each of which an element area is reduced and DC superimposition characteristics are further improved. A laminated inductor according to the present disclosure comprises: an element body 10 to which a magnetic layer is laminated, and the bottom surface of which is quadrangular; a first external electrode E1, second external electrode E2, third external electrode E3, and fourth external electrode E4 which are provided to the four corners of the bottom surface of the element body 10; a first winding part W1 to which a plurality of conductor layers that are disposed inside the element body are connected in the lamination direction, and which has a winding axis P in the lamination direction; a second winding part which is provided higher in the lamination direction than the first winding part W1, to which a plurality of conductor layers that are disposed in the element body are connected in the lamination direction, and which has a winding axis P in the lamination direction; a first through hole T1 which electrically connects the first external electrode E1 and one end of the first winding part W1, and which extends in the lamination direction; a second through hole T2 which electrically connects the second external electrode E2 and the other end of the first winding part W1, and which extends in the lamination direction; a third through hole T3 which electrically connects the third external electrode E3 and one end of the second winding part W2, and which extends in the lamination direction; and a fourth through hole T4 which electrically connects the fourth external electrode E4 and the other end of the second winding part W2, and which extends in the lamination direction, wherein the first winding part W1 and the second winding part W2 have an elliptical shape in plan view, and the first winding part W1 and / or the second winding part W2 are / is provided with an avoidance part A that avoids one through hole among the first through hole T1 to the fourth through hole T4.

Description

Multilayer inductor and multilayer inductor array

[0001] The present disclosure relates to stacked inductors and stacked inductor arrays.

[0002] Patent Document 1 discloses a laminated electronic component (laminated inductor) having an element body including a magnetic layer containing magnetic particles, a coil built into the element body, and external electrodes provided on the bottom surface of the element body and each electrically connected to one of the ends of the coil, wherein the coil includes a first coil and a second coil, and the external electrodes include a first external electrode, a second external electrode, a third external electrode and a fourth external electrode that are each electrically connected to one of the ends of the first coil and the second coil.

[0003] Japanese Patent Application Laid-Open No. 2022-922

[0004] The multilayer inductor described in Patent Document 1 has room for further improvement in terms of DC bias characteristics. Specifically, in the schematic diagram of the conventional multilayer inductor described in Patent Document 1 (see FIG. 7A ), a corner Z is provided on the inner periphery of the coil C when viewed from above. Note that the term "corner" as used herein refers to a position where a flat portion and a curved portion intersect on the inner periphery of the coil. Furthermore, the term "corner" may include a position where two flat portions intersect, or a position where two curved portions intersect.

[0005] When a magnetic field analysis by simulation was performed on the conventional laminated inductor shown in Fig. 7A, the present inventors found that magnetic saturation occurred in the corners Z (particularly in the region R where the corners Z are concentrated), as shown in Fig. 7B. The present inventors then discovered that the DC bias characteristics of the laminated inductor can be further improved by reducing the magnetic saturation.

[0006] On the other hand, in a laminated inductor, if the coil has a shape without corners when viewed from above (for example, a circular or oval shape), as shown in Figure 8, the lead-out wiring DW that electrically connects the coil C and the external electrode needs to be located outside the coil C when viewed from above, which increases the element area.

[0007] In view of the above, an object of the present disclosure is to provide a laminated inductor and a laminated inductor array that have a reduced element area and further improved DC bias characteristics.

[0008] a first winding portion having a winding axis in the lamination direction, and a plurality of conductor layers disposed within the element body connected in the lamination direction; a second winding portion located above the first winding portion in the lamination direction, and having a winding axis in the lamination direction, and a plurality of conductor layers disposed within the element body connected in the lamination direction; a first through-hole electrically connecting one end of the first winding portion to the first external electrode and extending in the lamination direction; a second through-hole electrically connecting the other end of the first winding portion to the second external electrode and extending in the lamination direction; a third through-hole electrically connecting one end of the second winding portion to the third external electrode and extending in the lamination direction; and a fourth through hole that electrically connects the other end of the second winding portion to the fourth external electrode and extends in the stacking direction, wherein the first winding portion and the second winding portion have an oval shape when viewed from above, and the first winding portion and / or the second winding portion has an avoidance portion that avoids any one of the first through hole to the fourth through hole.

[0009] a first external electrode, a second external electrode, a third external electrode, a fourth external electrode, a fifth external electrode, a sixth external electrode, a seventh external electrode, and an eighth external electrode provided along four sides of the bottom surface of the element body; a first winding section in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a second winding section located above the first winding section in the stacking direction and in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a third winding section in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a fourth winding section located above the third winding section in the stacking direction and in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a first through hole extending in the stacking direction and electrically connecting one end of the first winding section to the first external electrode; a second through-hole electrically connecting the other end of the first winding portion and the second external electrode and extending in the stacking direction; a third through-hole electrically connecting one end of the second winding portion and the third external electrode and extending in the stacking direction; a fourth through-hole electrically connecting the other end of the second winding portion and the fourth external electrode and extending in the stacking direction; a fifth through-hole electrically connecting one end of the third winding portion and the fifth external electrode and extending in the stacking direction; a sixth through-hole electrically connecting the other end of the third winding portion and the sixth external electrode and extending in the stacking direction; a seventh through-hole electrically connecting one end of the fourth winding portion and the seventh external electrode and extending in the stacking direction; and an eighth through-hole electrically connecting the other end of the fourth winding portion and the eighth external electrode and extending in the stacking direction, wherein the third winding portion is disposed in a direction intersecting the stacking direction with respect to the first winding portion, the fourth winding portion is disposed in a direction intersecting the stacking direction with respect to the second winding portion, the first winding portion to the fourth winding portion are oval in shape in a top view, and the first winding portion or the second winding portion includes a first avoidance portion that avoids any one of the first through hole to the fourth through hole,The third winding portion or the fourth winding portion includes a second avoidance portion that avoids any one of the fifth through-hole to the eighth through-hole.

[0010] According to the present disclosure, it is possible to provide a multilayer inductor with improved DC bias characteristics while reducing the element area. Specifically, because the first winding portion and the second winding portion have an oval shape in top view, the number of avoidance portions and the number of corners of the multilayer inductor can be reduced compared to the multilayer inductor described in Patent Document 1, thereby reducing magnetic saturation. Therefore, the DC bias characteristics of the multilayer inductor can be further improved. Furthermore, because the first winding portion and / or the second winding portion are provided with an avoidance portion that avoids one of the first through fourth through holes, it is possible to further reduce the element area compared to a multilayer inductor having a completely oval-shaped coil without an avoidance portion.

[0011] FIG. 1 is a perspective view schematically showing an example of a laminated inductor according to the present disclosure. FIG. 2 is a perspective view schematically showing an example of a first coil and a second coil according to the present disclosure. FIG. 3 is an exploded perspective view schematically showing an example of the internal structure of a laminated inductor according to the present disclosure. FIG. 4 is a perspective view schematically showing an example of a laminated inductor array according to the present disclosure. FIG. 5 is a perspective view schematically showing a modified example of a laminated inductor array according to the present disclosure. FIG. 6 is an explanatory diagram illustrating the results of a magnetic field analysis performed by simulation on the laminated inductor according to the present disclosure. FIG. 7A is a perspective view schematically showing a comparative example of a laminated inductor. FIG. 7B is an explanatory diagram illustrating the results of a magnetic field analysis performed by simulation on a comparative example of a conventional laminated inductor. FIG. 9 is a plan view of an inductor in which corners are not provided in the coil. FIG. 10 is a graph showing the results of DC superposition characteristics.

[0012] The laminated inductor of the present disclosure will be described below. Note that the present disclosure is not limited to the following configurations and may be modified as appropriate within the scope of the present disclosure. In addition, a combination of multiple individual preferred configurations described below also constitutes the present disclosure.

[0013] The laminated inductor of the present disclosure is used, for example, as a choke coil in a DC-DC converter, but can also be used for purposes other than as a choke coil.

[0014] In this specification, terms indicating the relationship between elements (e.g., "parallel," "orthogonal," etc.) and terms indicating the shape of elements do not only mean the strict literal form, but also mean a range of substantial equivalence, for example, a range including a difference of about a few percent. Note that in this specification, the direction in which the magnetic layers and coil conductors that make up the element body are stacked is referred to as the "stacking direction."

[0015] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0016] <Laminated Inductor> First, an embodiment of a laminated inductor according to the present disclosure will be described with reference to Figures 1 to 3. Figure 1 is a perspective view schematically showing an example of a laminated inductor according to the present disclosure, and Figure 2 is a perspective view schematically showing an example of a first coil and a second coil according to the present disclosure.

[0017] 1 and 2 includes an element body 10, a first external electrode E1, a second external electrode E2, a third external electrode E3, and a fourth external electrode E4, a first coil C1, a second coil C2, and a first through hole T1, a second through hole T2, a third through hole T3, and a fourth through hole T4. Each of the components will be described in detail below.

[0018] -Element body- The element body 10 is, for example, a hexahedron having six faces. As an example, it may be a rectangular parallelepiped or approximately rectangular parallelepiped shape. The corners and ridges of the element body 10 may be rounded. A corner is a portion where three faces of the element body 10 intersect, and a ridge is a portion where two faces of the element body 10 intersect.

[0019] 1, the length direction, width direction, and height direction of the laminated inductor 1A and the element body 10 are respectively indicated as direction L, direction W, and direction T. The length direction L, width direction W, and height direction T are perpendicular to each other.

[0020] 1 has a first main surface 11 and a second main surface 12 that face each other in the height direction T, a first end surface 13 and a second end surface 14 that face each other in the length direction L, and a first side surface 15 and a second side surface 16 that face each other in the width direction W. In the example shown in FIG. 1 , a first external electrode E1, a second external electrode E2, a third external electrode E3, and a fourth external electrode E4 are formed at the four corners of the first main surface 11 of the element body 10, respectively, and correspond to the mounting surface (bottom surface) of the element body 10.

[0021] FIG. 3 is an exploded perspective view schematically illustrating an example of the internal structure of the laminated inductor of the present disclosure. As shown in FIG. 3, the element body 10 is configured by stacking multiple magnetic layers ML in the height direction. The element body 10 may include a first coil C1 having a first winding portion W1, which will be described later, and a second coil C2 having a second winding portion W2. In this embodiment, as shown in FIG. 3, the element body 10 is configured by stacking multilayer groups G1 to G13 and forming first external electrodes E1 to fourth external electrodes E4 on the underside of the multilayer group G13. Note that the boundaries between layers in the multilayer structure of the element body 10 may disappear. Furthermore, each of the multilayer groups G1 to G13 may be configured by stacking multiple layers of the same pattern.

[0022] (Stacking Group G1) The stacking group G1 includes a magnetic layer ML and may constitute the second main surface 12 of the element body 10.

[0023] (Lamination group G2) The lamination group G2 includes a magnetic layer ML, a second winding portion W2 formed by winding a conductor layer, and a fourth through-hole (not shown). The lamination group G2 may further include a fourth connection portion J4 connecting the second winding portion W2 and the fourth through-hole, and a via hole (not shown) connecting to the second winding portion W2 of the lamination group G4.

[0024] The second winding portion W2 of the lamination group G2 has an oval shape in a top view. The term "oval shape" as used herein refers to a shape that has no corners in the inner peripheral portion of the winding portion except for the areas avoided by the avoidance portion. Specifically, it refers to an egg shape, an ellipse shape, or an oval shape in which curved portions and straight portions smoothly connect (oval track shape). Furthermore, the winding axis P of the second winding portion W2 may be offset from the center O of the element body 10 in a top view. In other words, the winding axis P of the coil and the center O of the element body 10 do not have to coincide.

[0025] When the end of the second winding portion W2 of the multilayer group G2 corresponding to the start of winding is defined as one end S and the end corresponding to the end of winding is defined as the other end F, the one end S may be located on a straight line L1 connecting the fourth external electrode E4 and the third external electrode E3 in a top perspective view. The one end S may be a connecting via hole with the via hole V of the multilayer group G3. The other end F may be located on a straight line L2 connecting the fourth external electrode E4 and the first external electrode E1 in a top perspective view. By configuring the start and end of winding in this way, the inner diameter of the second winding portion W2 can be maximized as much as possible, improving the characteristics of the inductor.

[0026] The fourth through hole (not shown) of the multilayer group G2 may be electrically connected to the other end F of the second winding portion W2. In this specification, the term "electrically connected" is not limited to a direct connection between the winding portion and the through hole, but is intended to allow for the presence of other elements such as an intervening object (e.g., a connecting portion). The fourth through hole T4 may be disposed above the fourth external electrode E4.

[0027] The fourth connection portion J4 of the multilayer group G2 may be interposed between the second winding portion W2 and a fourth through-hole (not shown). The fourth connection portion J4 may have a linear shape in top view. By adopting such a shape, the inner diameter of the second winding portion W2 can be maximized as much as possible, thereby improving the inductor characteristics.

[0028] (Multilayer Group G3) The multilayer group G3 includes a magnetic layer ML, a via hole V that connects the second winding portions W2 adjacent to each other in the stacking direction, and a fourth through hole T4.

[0029] The via hole V of the multilayer group G3 may be arranged at a position where it connects to one end S of the second winding portion W2 of the multilayer group G2. The via hole V of the multilayer group G3 may be arranged adjacent to the fourth through hole T4 in a top view at a distance that ensures electrical insulation.

[0030] The fourth through hole T4 of the multilayer group G3 may connect the fourth through holes T4 of the multilayer groups G2 and G4 adjacent in the stacking direction to each other, thereby providing electrical conduction with the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape that corresponds to the outer edge of the avoidance portion A (described below) when viewed from above. In other words, the shape of the fourth through hole T4 may be such that the distance from the avoidance portion A is kept constant.

[0031] (Lamination group G4) The lamination group G4 includes a magnetic layer ML, a second winding portion W2 formed by winding a conductor layer, and a fourth through hole T4. Furthermore, the lamination group G4 may include a via hole (not shown) that connects to the second winding portion W2 of the lamination group G6.

[0032] The second winding portion W2 of the multilayer group G4 has an oval shape in a top view. Furthermore, in a top perspective view, the second winding portion W2 of the multilayer group G4 may at least partially overlap the second winding portion W2 of the multilayer group G2. Furthermore, the winding axis P of the second winding portion W2 may be offset from the center O of the element body 10.

[0033] When the end of the second winding portion W2 of the multilayer group G4 corresponding to the start of winding is defined as one end S and the end of the second winding portion W2 corresponding to the end of winding is defined as the other end F, the one end S and the other end F may be located on a straight line L1 connecting the fourth external electrode E4 and the third external electrode E3 in a top perspective view. Furthermore, the one end S may be located closer to the third external electrode E3 than the other end F. The one end S may be connected to the via hole V of the multilayer group G5 through a via hole. The other end F may be connected to the via hole V of the multilayer group G3. By configuring the start and end of winding in this way, the inner diameter of the second winding portion W2 can be maximized as much as possible, improving the characteristics of the inductor.

[0034] The second winding portion W2 of the multilayer group G4 may include an avoidance portion A that avoids the fourth through hole T4. In a preferred embodiment of the avoidance portion A, the avoidance portion A may have a shape that protrudes toward the inner diameter of the coil beyond the fourth through hole T4 in a top view (a shape that bulges toward the inside of the coil). The avoidance portion A may also be provided in one location in the second winding portion W2. By using the avoidance portion A to avoid the fourth through hole T4, the element area can be reduced compared to an embodiment in which no avoidance portion is provided.

[0035] The fourth through hole T4 of the multilayer group G4 may connect the fourth through holes T4 of the multilayer groups G3 and G5 adjacent in the stacking direction to each other and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape corresponding to the outer edge of the avoidance portion A in a top perspective view.

[0036] (Multilayer Group G5) The multilayer group G5 includes a magnetic layer ML, a via hole V that connects the second winding portions W2 adjacent in the stacking direction, and a fourth through hole T4.

[0037] The via hole V of the multilayer group G5 may be arranged at a position where it connects to one end S of the second winding portion W2 of the above-described multilayer group G4. The via hole V of the multilayer group G5 may be arranged adjacent to the fourth through hole T4 in a top view at a distance that ensures electrical insulation.

[0038] The fourth through hole T4 of the multilayer group G5 may connect the fourth through holes T4 of the multilayer groups G4 and G6 adjacent to each other in the stacking direction, and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape that corresponds to the outer edge of the avoidance portion A in a top perspective view.

[0039] The multilayer group G6 includes a magnetic layer ML, a second winding portion W2 formed by winding a conductor layer, a third through hole (not shown), and a fourth through hole T4. The multilayer group G6 may further include a third connection portion J3 that connects the second winding portion W2 and the third through hole T3.

[0040] The second winding portion W2 of the multilayer group G6 has an oval shape in a top view. Furthermore, in a top perspective view, the second winding portion W2 of the multilayer group G6 may at least partially overlap with the second winding portion W2 of the multilayer group G4. Furthermore, the winding axis P of the second winding portion W2 may be offset from the center O of the element body 10 in a top view.

[0041] When the end of the second winding portion W2 of the multilayer group G6 corresponding to the start of winding is defined as one end S and the end corresponding to the end of winding is defined as the other end F, the one end S may be located on the line L3 connecting the third external electrode E3 and the second external electrode E2 in a top perspective view or inside the line L3. The other end F may be located on the line L1 connecting the fourth external electrode E4 and the third external electrode E3 in a top perspective view. The other end F may be connected to a via hole V of the multilayer group G5. By configuring the start and end of winding in this way, the inner diameter of the second winding portion W2 can be maximized as much as possible, improving the characteristics of the inductor.

[0042] The second winding portion W2 of the multilayer group G6 may include an avoidance portion A that avoids the fourth through hole T4. In a preferred embodiment of the avoidance portion A, the avoidance portion A may have a shape that protrudes further toward the inner diameter of the coil than the fourth through hole T4 when viewed from above. The avoidance portion A may also be provided in one location in the second winding portion W2. By using the avoidance portion A to avoid the fourth through hole T4, the element area can be made smaller than in an embodiment in which no avoidance portion is provided.

[0043] The third through-hole (not shown) of the multilayer group G6 is electrically connected to one end S of the second winding portion W2. The third through-hole may be disposed above the third external electrode E3.

[0044] The third connection portion J3 of the multilayer group G6 may be interposed between the second winding portion W2 and a third through-hole (not shown). The third connection portion J3 may have a curved shape in top view. This shape allows for proper connection between the second winding portion W2 and the third through-hole.

[0045] The curvature of the third connection portion J3 of the multilayer group G6 may be smaller than the curvature of the oval-shaped second winding portion W2. In other words, the third connection portion J3 may have a gentler curve than the second winding portion W2. By setting the curvature of the third connection portion J3 in this manner, the inner diameter of the second winding portion W2 can be maximized as much as possible, improving the inductor characteristics.

[0046] The fourth through hole T4 of the multilayer group G6 may connect the fourth through holes T4 of the multilayer groups G5 and G7 adjacent in the stacking direction to each other and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape corresponding to the outer edge of the avoidance portion A in a top perspective view.

[0047] (Multilayer Group G7) The multilayer group G7 may include a magnetic layer ML, a third through hole T3, and a fourth through hole T4.

[0048] The third through hole T3 of the multilayer group G7 may be electrically connected to the third through holes T3 of the multilayer groups G6 and G8 adjacent to each other in the stacking direction, and thus may be disposed on the third external electrode E3.

[0049] The fourth through hole T4 of the multilayer group G7 may be electrically connected to the fourth through holes T4 of the multilayer groups G6 and G8 adjacent to each other in the stacking direction, and thus may be disposed above the fourth external electrode E4.

[0050] (Lamination group G8) The lamination group G8 includes a magnetic layer ML, a first winding portion W1 formed by winding a conductor layer, a second through hole (not shown), a third through hole T3, and a fourth through hole T4. The lamination group G8 may further include a second connection portion J2 connecting the first winding portion W1 and the second through hole, and a via hole (not shown) connecting to the first winding portion W1 of the lamination group G10.

[0051] The first winding portion W1 of the multilayer group G8 has an oval shape in a top view. Furthermore, in a top perspective view, the first winding portion W1 of the multilayer group G8 may at least partially overlap with the first winding portion W1 of the multilayer group G10. Furthermore, the winding axis P of the first winding portion W1 may be offset from the center O of the element body 10 in a top view.

[0052] When the end of the first winding portion W1 of the multilayer group G8 corresponding to the start of winding is defined as one end S and the end corresponding to the end of winding is defined as the other end F, the one end S may be located on a straight line L4 connecting the second external electrode E2 and the first external electrode E1 in a top perspective view. The one end S may also be a connecting via hole to the via hole V of the multilayer group G9. The other end F may be located on a straight line L3 connecting the third external electrode E3 and the second external electrode E2 in a top perspective view or inside the straight line L3. By configuring the start and end of winding in this way, the inner diameter of the first winding portion W1 can be maximized as much as possible, improving the characteristics of the inductor.

[0053] The first winding portion W1 of the multilayer group G8 may include an avoidance portion A that avoids the fourth through hole T4. The avoidance portion A may be provided in one location in the first winding portion W1. In a preferred embodiment of the avoidance portion A, the avoidance portion A may have a shape that protrudes further toward the inner diameter of the coil than the fourth through hole T4 in a top view. By using the avoidance portion A to avoid the fourth through hole T4, the element area can be made smaller than in an embodiment in which an avoidance portion is not provided.

[0054] The second through hole (not shown) of the multilayer group G8 may be electrically connected to the other end F of the first winding portion W1. The second through hole T2 may be disposed above the second external electrode E2.

[0055] The second connection portion J2 of the multilayer group G8 may be interposed between the first winding portion W1 and a second through-hole (not shown). The second connection portion J2 may have a curved shape in top view. This shape allows for proper connection between the first winding portion W1 and the second through-hole.

[0056] The curvature of the second connection portion J2 of the multilayer group G8 may be smaller than the curvature of the oval-shaped first winding portion W1. In other words, the second connection portion J2 may have a gentler curve than the first winding portion W1. By setting the curvature of the second connection portion J2 in this manner, the inner diameter of the first winding portion W1 can be maximized as much as possible, improving the characteristics of the inductor.

[0057] The third through hole T3 of the multilayer group G8 may be electrically connected to the third through holes T3 of the multilayer groups G7 and G9 adjacent to each other in the stacking direction, and thus may be disposed above the third external electrode E3.

[0058] The fourth through hole T4 of the multilayer group G8 may connect the fourth through holes T4 of the multilayer groups G7 and G9 adjacent to each other in the stacking direction, and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape that corresponds to the outer edge of the avoidance portion A in a top perspective view.

[0059] (Stacking group G9) The stacking group G9 may include a magnetic layer ML, a via hole V connecting adjacent first winding portions W1 in the stacking direction, a second through hole T2, a third through hole T3, and a fourth through hole T4.

[0060] The via hole V of the multilayer group G9 may be arranged at a position where it connects to one end S of the first winding portion W1 of the above-described multilayer group G8. The via hole V of the multilayer group G9 may be arranged adjacent to the second through hole T2 in a top view at a distance that ensures electrical insulation from the second through hole T2.

[0061] The second through hole T2 of the multilayer group G9 may be electrically connected to the second through holes T2 of the multilayer groups G8 and G10 adjacent to each other in the stacking direction, and thus may be disposed above the second external electrode E2.

[0062] The third through hole T3 of the multilayer group G9 may be electrically connected to the third through holes T3 of the multilayer groups G8 and G10 adjacent to each other in the stacking direction, and thus may be disposed above the third external electrode E3.

[0063] The fourth through hole T4 of the multilayer group G9 may connect the fourth through holes T4 of the multilayer groups G8 and G10 adjacent to each other in the stacking direction, and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape that corresponds to the outer edge of the avoidance portion A in a top perspective view.

[0064] (Lamination group G10) The lamination group G10 includes a magnetic layer ML, a first winding portion W1 formed by winding a conductor layer, a second through hole T2, a third through hole T3, and a fourth through hole T4. The lamination group G10 may further include a via hole (not shown) that connects to the first winding portion W1 of the lamination group G12.

[0065] The first winding portion W1 of the multilayer group G10 has an oval shape in a top view. Furthermore, in a top perspective view, the first winding portion W1 of the multilayer group G10 may at least partially overlap with the first winding portion W1 of the multilayer group G8. Furthermore, the winding axis P of the first winding portion W1 may be offset from the center O of the element body 10 in a top view.

[0066] When the end of the first winding portion W1 of the multilayer group G10 corresponding to the start of winding is defined as one end S and the end corresponding to the end of winding is defined as the other end F, the one end S and the other end F may be located on a straight line L4 connecting the second external electrode E2 and the first external electrode E1 in a top perspective view. Furthermore, the one end S may be located closer to the first external electrode E1 than the other end F. The one end S may be connected to the via hole V of the multilayer group G11 through a via hole. The other end F may be connected to the via hole V of the multilayer group G9. By configuring the start and end of winding in this way, the inner diameter of the first winding portion W1 can be maximized as much as possible, improving the characteristics of the inductor.

[0067] The first winding portion W1 of the multilayer group G10 may include an avoidance portion A that avoids the fourth through hole T4. In a preferred embodiment of the avoidance portion A, the avoidance portion A may have a shape that protrudes further toward the inner diameter of the coil than the fourth through hole T4 in a top view. The avoidance portion A may be provided in one location in the first winding portion W1. By using the avoidance portion A to avoid the fourth through hole T4, the element area can be made smaller than in an embodiment in which no avoidance portion is provided.

[0068] The second through-hole T2 of the multilayer group G10 may be electrically connected to the second external electrode E2 by connecting the second through-holes T2 of the multilayer groups G9 and G11 adjacent to each other in the stacking direction, and therefore the second through-hole T2 may be disposed above the second external electrode E2.

[0069] The third through hole T3 of the multilayer group G10 may be electrically connected to the third through holes T3 of the multilayer groups G9 and G11 adjacent to each other in the stacking direction, and thus may be disposed above the third external electrode E3.

[0070] The fourth through hole T4 of the multilayer group G10 may connect the fourth through holes T4 of the multilayer groups G9 and G11 adjacent to each other in the stacking direction, and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape that corresponds to the outer edge of the avoidance portion A in a top perspective view.

[0071] (Stacking group G11) The stacking group G11 may include a magnetic layer ML, a via hole V connecting adjacent first winding portions W1 in the stacking direction, a second through hole T2, a third through hole T3, and a fourth through hole T4.

[0072] The via hole V of the multilayer group G11 may be arranged at a position where it connects to one end S of the first winding portion W1 of the above-described multilayer group G10. The via hole V of the multilayer group G11 may be arranged adjacent to the second through hole T2 in a top view at a distance that ensures electrical insulation.

[0073] The second through-hole T2 of the multilayer group G11 may be electrically connected to the second external electrode E2 by connecting the second through-holes T2 of the multilayer groups G10 and G12 adjacent to each other in the stacking direction, and therefore the second through-hole T2 may be disposed above the second external electrode E2.

[0074] The third through hole T3 of the multilayer group G11 may be electrically connected to the third through holes T3 of the multilayer groups G10 and G12 adjacent to each other in the stacking direction, and thus may be disposed above the third external electrode E3.

[0075] The fourth through hole T4 of the multilayer group G11 may connect the fourth through holes T4 of the multilayer groups G10 and G12 adjacent in the stacking direction to each other and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape that corresponds to the outer edge of the avoidance portion A in a top perspective view.

[0076] (Lamination group G12) The lamination group G12 includes a magnetic layer ML, a first winding portion W1 formed by winding a conductor layer, a first through hole (not shown), a second through hole T2, a third through hole T3, and a fourth through hole T4. The lamination group G12 may further include a first connection portion J1 that connects the first winding portion W1 and the first through hole.

[0077] The first winding portion W1 of the multilayer group G12 has an oval shape in a top view. In addition, in a top perspective view, the first winding portion W1 of the multilayer group G12 may at least partially overlap with the first winding portion W1 of the multilayer group G10. In addition, the winding axis P of the first winding portion W1 may be offset from the center O of the element body 10 in a top view.

[0078] When the end of the first winding portion W1 of the multilayer group G12 corresponding to the start of winding is defined as one end S and the end corresponding to the end of winding is defined as the other end F, the one end S may be located on a straight line L2 connecting the fourth external electrode E4 and the first external electrode E1 in a top perspective view. The other end F may be located on a straight line L4 connecting the second external electrode E2 and the first external electrode E1 in a top perspective view. The other end F may also be connected to a via hole V of the multilayer group G11. By configuring the start and end of winding in this way, the inner diameter of the first winding portion W1 can be maximized as much as possible, improving the characteristics of the inductor.

[0079] The first winding portion W1 of the multilayer group G12 may include an avoidance portion A that avoids the fourth through hole T4. The avoidance portion A may be provided in one location in the first winding portion W1. In a preferred embodiment of the avoidance portion A, the avoidance portion A may have a shape that protrudes further toward the inner diameter of the coil than the fourth through hole T4 in a top view. By using the avoidance portion A to avoid the fourth through hole T4, the element area can be made smaller than in an embodiment in which an avoidance portion is not provided.

[0080] The first through hole (not shown) of the multilayer group G12 is electrically connected to one end S of the first winding part W1. The first through hole T1 may be disposed above the first external electrode E1.

[0081] The first connection portion J1 of the multilayer group G12 may be interposed between the first winding portion W1 and a first through-hole (not shown). The shape of the first connection portion J1 in a top view may be linear. By adopting such a shape, the inner diameter of the second winding portion W2 can be maximized as much as possible, thereby improving the characteristics of the inductor.

[0082] The second through-hole T2 of the multilayer group G12 may be electrically connected to the second external electrode E2 by connecting the second through-holes T2 of the multilayer groups G11 and G13 adjacent to each other in the stacking direction, and therefore may be disposed above the second external electrode E2.

[0083] The third through hole T3 of the multilayer group G12 may be electrically connected to the third external electrode E3 by connecting the third through holes T3 of the multilayer groups G11 and G13 adjacent to each other in the stacking direction, and therefore may be disposed above the third external electrode E3.

[0084] The fourth through hole T4 of the multilayer group G12 may connect the fourth through holes T4 of the multilayer groups G11 and G13 adjacent in the stacking direction to each other and be electrically connected to the fourth external electrode E4. Therefore, the fourth through hole T4 may be disposed above the fourth external electrode E4. Furthermore, the fourth through hole T4 may have a shape corresponding to the outer edge of the avoidance portion A in a top perspective view.

[0085] (Multilayer group G13) The multilayer group G13 may include a magnetic layer ML, a first through hole T1, a second through hole T2, a third through hole T3, and a fourth through hole T4. The areas of the first through holes T1 to the fourth through holes T4 of the multilayer groups G1 to G13 in a top view may be approximately the same.

[0086] In a preferred embodiment of the multilayer group, an additional multilayer group may be provided below the multilayer group G13. The additional multilayer group may have first through holes T1 to T4 that are larger in area as viewed from above than the first through holes T1 to T4 of the multilayer groups G1 to G13. By making the planar areas of the first through holes T1 to T4 of the additional multilayer group larger than the first external electrodes E1 to E4, even if shrinkage occurs during firing, the external electrodes can be positioned as desired by forming the first external electrodes E1 to E4 after firing. Because the additional multilayer group is provided to buffer misalignment, its thickness may be thinner than that of the multilayer groups G1 to G13.

[0087] The thickness of the first winding portion W1 and / or the second winding portion W2 in each lamination group may be the same. Furthermore, the thickness of the first through holes T1 to T4 and / or the via holes V may be thinner than the thickness of the first winding portion W1 and / or the second winding portion W2 in each lamination group. The thickness of the via holes V may vary from layer to layer. For example, the via holes V between the first winding portion W1 (lamination groups G3 and G5) and between the second winding portion W2 (lamination groups G9 and G11) may be thinner than the via holes V between the first winding portion W1 and the second winding portion W2 (lamination group G7).

[0088] The first winding portion W1 and / or the second winding portion W2, the first through holes T1 to T4, and the via holes V may be made of, for example, metal conductors such as Ag and / or Cu, and may be made of the same or different materials. The first winding portion W1 and / or the second winding portion W2, the first through holes T1 to T4, and / or the via holes V may be formed, for example, by printing a conductive paste on the magnetic layer ML described above, and then printing the magnetic layer ML on top of the conductive paste after printing the conductive paste.

[0089] As described above, when the element body 10 has a laminated structure including the laminated groups G1 to G13, the degree of freedom in designing the laminated inductor 1A is increased. For example, when manufacturing a laminated inductor 1A including the first external electrode E1, the second external electrode E2, the third external electrode E3, and the fourth external electrode E4 on the bottom surface (first main surface 11) of the element body 10, it becomes easier to extend the first winding portion W1 and the second winding portion W2 to the bottom surface side. Note that the laminated structure including the laminated groups G1 to G13 may be formed by repeatedly printing the material constituting the magnetic layer ML, the material constituting the first winding portion W1 or the second winding portion W2, and the material constituting the through holes and / or via holes sequentially from the second main surface 12 side or the first main surface 11 side of the element body 10 using, for example, screen printing or the like until the via holes reach the desired thickness, or by sputtering, inkjet printing, or other known methods.

[0090] Additional elements related to the base body 10 will now be described. The magnetic layer ML may include metal magnetic particles made of a magnetic material. The metal magnetic particles may include Fe and / or Si. More specifically, the particles may be Fe particles or Fe alloy particles. The Fe alloy may be an Fe-Si alloy, an Fe-Si-Cr alloy, an Fe-Si-Al alloy, an Fe-Si-B-P-Cu-C alloy, an Fe-Si-B-Nb-Cu alloy, or the like. The metal magnetic particles may also include impurities such as Cr, Mn, Cu, Ni, P, S, or Co that are not intended during manufacturing. The metal magnetic particles may also be contained in a magnetic paste. Therefore, the metal magnetic particles may include an element (e.g., Cr, Al, Li, Zn) that is more easily oxidized than the Fe added during magnetic paste production.

[0091] The surfaces of the above-mentioned metal magnetic particles may be covered with an insulating coating (not shown). Covering the surfaces of the metal magnetic particles with an insulating coating can improve the insulation between the metal magnetic particles. Methods for forming the insulating coating on the surfaces of the metal magnetic particles include the sol-gel method and the mechanochemical method. The material constituting the insulating coating may be an oxide of P, Si, or the like, zinc phosphate, or manganese phosphate. The insulating coating may also be an oxide film formed by oxidizing the surfaces of the metal magnetic particles. The thickness of the insulating coating is preferably 1 nm or more and 50 nm or less, more preferably 1 nm or more and 30 nm or less, and even more preferably 1 nm or more and 20 nm or less. For example, a cross section obtained by polishing an inductor sample can be photographed with a scanning electron microscope (SEM), and the thickness of the insulating coating covering the surfaces of the metal magnetic particles can be measured from the obtained SEM photograph.

[0092] The average particle size of the metal magnetic particles in the magnetic layer ML is preferably 1 μm or more and 30 μm or less, more preferably 1 μm or more and 20 μm or less, and even more preferably 1 μm or more and 10 μm or less. The average particle size of the metal magnetic particles in the magnetic layer can be measured using the procedure described below. An inductor sample is cut to obtain a cross section of the sample. Specifically, the sample cross section is obtained by cutting through the center of the element body so as to be perpendicular to the mounting surface and end surface of the element body. Multiple (e.g., five) regions (e.g., 130 μm × 100 μm) of the obtained cross section are photographed using an SEM, and the obtained SEM images are analyzed using image analysis software (e.g., image analysis software WinROOF2021 (manufactured by Mitani Corporation)) to determine the circle-equivalent diameter of the metal magnetic particles. The average of the obtained circle-equivalent diameters is taken as the average particle size of the metal magnetic particles.

[0093] When forming the element body 10, a heat treatment is performed. In this case, the metal magnetic particles contained in the element body 10 have an oxide film on their surfaces. This oxide film originates from the metal magnetic particles and is formed by the heat treatment. In the element body 10, adjacent metal magnetic particles may be joined to each other via the oxide film.

[0094] In order to further improve the strength of the element body 10, the element body 10 may be impregnated with a resin material after firing the element body 10. As an example of a resin that increases the strength of the element body, an epoxy resin and / or a phenol resin and / or a silicone resin may be used.

[0095] -External Electrodes- The external electrodes are provided on the bottom surface of the element body 10. The external electrodes may include a first external electrode E1, a second external electrode E2, a third external electrode E3, and a fourth external electrode E4. The first external electrode E1 and the second external electrode E2 may be electrically connected to the first winding portion W1. The third external electrode E3 and the fourth external electrode E4 may be electrically connected to the second winding portion W2. Providing external electrodes on the bottom surface (first main surface 11) of the element body 10 enables the multilayer inductor 1A to be properly mounted on a mounting board or the like.

[0096] The first external electrode E1 may be provided only on the first main surface 11 of the element body 10, or may be provided across the first main surface 11 of the element body 10 and the first end surface 13 and / or the first side surface 15.

[0097] The second external electrode E2 may be provided only on the first main surface 11 of the element body 10, or may be provided across the first main surface 11, the first end surface 13 and / or the second side surface 16 of the element body 10.

[0098] The third external electrode E3 may be provided only on the first main surface 11 of the element body 10, or may be provided across the first main surface 11, the second end surface 14 and / or the second side surface 16 of the element body 10.

[0099] The fourth external electrode E4 may be provided only on the first main surface 11 of the element body 10, or may be provided across the first main surface 11, the second end surface 14 and / or the first side surface 15 of the element body 10.

[0100] In a preferred embodiment of the external electrodes, the planar area of ​​the external electrodes as viewed from the mounting surface side of the element body 10 may be smaller than the planar area of ​​the first through holes T1 to fourth through holes T4 of the multilayer group G13. By making the planar area of ​​the external electrodes smaller than the first through holes T1 to fourth through holes T4 of the multilayer group G13, it is possible to easily connect the external electrodes, which require a certain positional accuracy on the element body, to the through holes, which may become misaligned due to shrinkage caused by firing.

[0101] The external electrodes may be made of various materials such as Cu and / or Au, for example. The external electrodes may be formed by any method, but may be plated electrodes formed by plating (for example, electroless plating or sputtering), or may have a laminated structure of two or more layers by forming a plated layer of Ni, Sn, or the like on the external electrodes using a plating method after the external electrodes are formed.

[0102] -First Coil- The first coil C1 is provided inside the element body 10. The first coil C1 may include a plurality of first winding portions W1 connected to each other by via holes V, a first through hole T1, a second through hole T2, a first connection portion J1 connecting one end of the first winding portion W1 to the first through hole T1, and a second connection portion J2 connecting the other end of the first winding portion W1 to the second through hole T2.

[0103] As described above, the multiple first winding portions W1 are provided across three stacking groups (stack groups G8, G10, and G12). As a result, the first coil C1 has a three-layer structure with 2.5 turns. Furthermore, the length in the stacking direction of the via holes V connecting the multiple first winding portions W1 together may be shorter than the length of the first through holes T1 or the length of the second through holes T2.

[0104] As described above, the plurality of first winding portions W1 may include avoidance portions A that avoid the fourth through holes T4. By avoiding the fourth through holes T4 with the avoidance portions A, the element area can be made smaller than in an embodiment in which no avoidance portions are provided.

[0105] The first through hole T1 may electrically connect the end of the first winding portion W1 of the first coil C1 that is closest to the bottom surface (first main surface 11) of the element body 10 to the first external electrode E1. A first connection portion J1 may be interposed between one end of the first winding portion W1 and the first through hole T1. The first through hole T1 may extend along the stacking direction (e.g., the height direction T). The first through hole T1 may have a stacked structure.

[0106] The second through hole T2 may electrically connect the other end of the first coil C1 and the second external electrode E2. A second connection portion J2 may be interposed between the other end of the first winding portion W1 and the second through hole T2. The second through hole T2 may extend along the stacking direction (e.g., the height direction T). The second through hole T2 may have a stacked structure.

[0107] - Second Coil - The second coil C2 is provided inside the element body 10, above the first coil C1 in the stacking direction. The second coil C2 may include a plurality of second winding portions W2 connected to each other by via holes V, a third through hole T3, a fourth through hole T4, a third connection portion J3 connecting one end of the second winding portion W2 to the third through hole T3, and a fourth connection portion J4 connecting the other end of the second winding portion W2 to the fourth through hole T4.

[0108] As described above, the second winding portions W2 are provided across the three stacking groups (stack groups G2, G4, and G6). As a result, the second coil C2 has a three-layer structure with 2.5 turns. Furthermore, the length in the stacking direction of the via holes V connecting the second winding portions W2 together may be shorter than the length of the third through holes T3 or the length of the fourth through holes T4.

[0109] As described above, the plurality of second winding portions W2 may include an avoidance portion A that avoids the fourth through hole T4, except for the second winding portion W2 that is electrically connected to the fourth through hole T4. By avoiding the fourth through hole T4 with the avoidance portion A, the element area can be made smaller than in an embodiment in which an avoidance portion is not provided.

[0110] The third through hole T3 may electrically connect the end of the second winding portion W2 of the second coil C2 that is closest to the bottom surface (first main surface 11) of the element body 10 to the third external electrode E3. A third connection portion J3 may be interposed between one end of the second winding portion W2 and the third through hole T3. The third through hole T3 may extend along the stacking direction (e.g., the height direction T). The third through hole T3 may have a stacked structure.

[0111] The fourth through hole T4 may connect the other end of the second coil C2 and the fourth external electrode E4. A fourth connection portion J4 may be interposed between the other end of the second winding portion W2 and the fourth through hole T4. The fourth through hole T4 may extend along the stacking direction (e.g., the height direction T). The fourth through hole T4 may have a stacked structure.

[0112] The laminated inductor 1A includes the above-described element body 10, the first external electrodes E1 to E4, the first coil C1 including the first winding portion W1, the second coil C2 including the second winding portion W2, and the first through holes T1 to T4. Because the first winding portion W1 and the second winding portion W2 are oval in shape when viewed from above, the number of avoidance portions is reduced compared to conventional laminated inductors (see FIG. 7 ), thereby reducing the number of corners of the laminated inductor and reducing magnetic saturation. This further improves the DC bias characteristics of the laminated inductor. Furthermore, because the first winding portion W1 and / or the second winding portion W2 includes an avoidance portion A that avoids one of the first through holes T1 to T4, the element area can be further reduced compared to a laminated inductor including a completely oval coil without an avoidance portion.

[0113] <Additional Configuration of the Multilayer Inductor> In a preferred configuration of the multilayer inductor 1A, the lengths of the through holes in the stacking direction have the following relationship: length of the fourth through hole T4 > length of the third through hole T3 > length of the second through hole T2 > length of the first through hole T1, and the avoidance portion A may avoid the fourth through hole T4. Specifically, the avoidance portion A may avoid the fourth through hole T4, which is set to be the longest. Furthermore, the avoidance portion A may be provided in the second winding portion W2 of the multilayer groups G4 and G6 and the first winding portion W1 of the multilayer groups G8, G10, and G12, except for the second winding portion W2 of the multilayer group G2. With this configuration, the avoidance portion A can be provided in many of the first winding portion W1 and the second winding portion W2, and the avoidance portion A can further reduce the element area.

[0114] Furthermore, the first winding portion W1 and / or the second winding portion W2 may be provided with an avoidance portion A that avoids any one of the first through hole T1 to the fourth through hole T4, and the winding axis P of the first winding portion W1 and the winding axis P of the second winding portion W2 may be offset from the center O of the element body 10 when viewed from above. With the above configuration, the wiring that protrudes outside the first winding portion W1 and the second winding portion W2 can be reduced, further reducing the element area.

[0115] Furthermore, the direction of the deviation of winding axis P may be toward the side where avoidance portion A is provided when viewed from above. For example, in the example shown in Fig. 3, winding axis P may be shifted toward the side where avoidance portion A is provided (the +W direction). With this configuration, it is possible to further reduce the amount of wiring that protrudes from first winding portion W1 and second winding portion W2 outside avoidance portion A, thereby further reducing the element area.

[0116] In a preferred configuration of the laminated inductor 1A, one end of the first winding portion W1 and the first through-hole T1 are connected via a linear first connection portion J1, the other end of the first winding portion W1 and the second through-hole T2 are connected via a curved second connection portion J2, one end of the second winding portion W2 and the third through-hole T3 are connected via a curved third connection portion J3, and the other end of the second winding portion W2 and the fourth through-hole T4 are connected via a linear fourth connection portion J4. For example, in the example shown in Figures 2 and 3, the connection portions on the -W direction side in top view (the second connection portion J2 and the third connection portion J3) are curved, and the connection portions on the +W direction side (the first connection portion J1 and the fourth connection portion J4) are linear in top view. This allows the winding axes P of the first winding portion W1 and the second winding portion W2 to be appropriately offset from the center O of the element body in top view, as described above. Furthermore, since the connection portion on the +W direction side has a linear shape when viewed from above, the amount of wiring that protrudes from the first winding portion W1 and the second winding portion W2 outside the avoidance portion A can be reduced, allowing the element area to be further reduced.

[0117] Furthermore, in the curved second and third connection portions J2 and J3 described above, the curvature of the second and third connection portions J2 and J3 may be smaller than the curvature of the first and second winding portions W1 and W2. By making the curvature of the second and third connection portions J2 and J3 as small as possible (making the curve gentler), the inner diameter of the first and second winding portions W1 and W2 can be maximized as much as possible, thereby improving the inductance characteristics.

[0118] The second external electrode E2 and the third external electrode E3 may be arranged along one side of the bottom surface of the rectangular element body. With this configuration, the second external electrode E2 and the third external electrode E3 are not arranged diagonally, and the second through-hole T2 and the other end of the first winding portion W1 electrically connected to the second external electrode E2, and the third through-hole T3 and one end of the second winding portion W2 electrically connected to the third external electrode E3 can be appropriately arranged, thereby further reducing the element area.

[0119] <Laminated Inductor Array> Next, the laminated inductor array of the present disclosure will be described with reference to Fig. 4. Fig. 4 is a perspective view schematically showing an example of the laminated inductor array of the present disclosure.

[0120] The laminated inductor array 1B of the present disclosure comprises three first and second coils arranged side by side in a direction intersecting the lamination direction to form a coil array. Specifically, in addition to a first winding portion W1 and a second winding portion W2, the laminated inductor array 1B may include a third winding portion W3, a fourth winding portion W4, a fifth winding portion W5, and a sixth winding portion W6 formed by winding conductor layers.

[0121] The third winding portion W3 and the fifth winding portion W5 may be aligned with the first winding portion W1 in a direction intersecting the stacking direction. The fourth winding portion W4 and the sixth winding portion W6 may be aligned with the second winding portion W2 in a direction intersecting the stacking direction. The third winding portion W3, the fifth winding portion W5, and the first winding portion W1 have substantially the same structure, and the fourth winding portion W4, the sixth winding portion W6, and the second winding portion W2 have substantially the same structure.

[0122] The third winding portion W3 may be electrically connected to a fifth external electrode (not shown) and a sixth external electrode E6. Specifically, the end of the third winding portion W3 closest to the bottom surface may be electrically connected to the fifth external electrode by a fifth through-hole (not shown). Furthermore, the other end of the third winding portion W3 may be connected to the sixth external electrode E6 by a sixth through-hole T6.

[0123] The fourth winding portion W4 may be electrically connected to a seventh external electrode E7 and an eighth external electrode (not shown). Specifically, the end of the fourth winding portion W4 closest to the bottom surface may be connected to the seventh external electrode E7 via a seventh through-hole T7. The other end of the fourth winding portion W4 may be connected to the eighth external electrode E7 via an eighth through-hole T8.

[0124] The fifth winding portion W5 may be electrically connected to a ninth external electrode (not shown) and a tenth external electrode E10. Specifically, the end of the fifth winding portion W5 closest to the bottom surface may be connected to the ninth external electrode by a ninth through-hole (not shown). Furthermore, the other end of the fifth winding portion W5 may be connected to the tenth external electrode E10 by a tenth through-hole T10.

[0125] The sixth winding portion W6 may be electrically connected to the eleventh external electrode E11 and the twelfth external electrode E12. Specifically, the end of the sixth winding portion W6 closest to the bottom surface may be connected to the eleventh external electrode E11 via the eleventh through-hole T11. The other end of the sixth winding portion W6 may be connected to the twelfth external electrode E12 via the twelfth through-hole T12.

[0126] In the laminated inductor array of the present disclosure, the first winding portion W1 to the sixth winding portion W6 have an oval shape in a top view, and the first winding portion W1 and / or the second winding portion W2 have a first avoidance portion A1 that avoids any one of the first through-hole T1 to the fourth through-hole, the third winding portion W3 and / or the fourth winding portion W4 have a second avoidance portion A2 that avoids any one of the fifth through-hole to the eighth through-hole T8, and the fifth winding portion W5 and / or the sixth winding portion W6 have a third avoidance portion A3 that avoids any one of the ninth through-hole to the twelfth through-hole T12. Specifically, as shown in FIG. 4 , the first avoidance portion A1 avoids the fourth through-hole T4, the second avoidance portion A2 avoids the eighth through-hole T8, and the third avoidance portion A3 avoids the twelfth through-hole T12.

[0127] According to the multilayer inductor array 1B of the present disclosure, the first winding portion W1 to the fourth winding portion W4 have an oval shape when viewed from above, and therefore, similar to the multilayer inductor 1A of the present disclosure, magnetic saturation can be reduced and the DC bias characteristics can be further improved. Furthermore, since the first avoidance portion A1, the second avoidance portion A2, and the third avoidance portion A3 are provided, similar to the multilayer inductor 1A of the present disclosure, the element area can be further reduced.

[0128] Next, a modified example of the laminated inductor array of the present disclosure will be described with reference to Fig. 5. Fig. 5 is a perspective view schematically showing a modified example of the laminated inductor array of the present disclosure. Note that this modified example differs from the laminated inductor array described above in terms of the positional relationship between the first avoidance portion A1 and the third avoidance portion and the second avoidance portion A2. The other configurations are as described for the laminated inductor array described above.

[0129] As shown in FIG. 5 , in the multilayer inductor array 1C of this modified example, the second avoidance portion A2 is not arranged along the same side of the element body 10 as the first avoidance portion A1 and the third avoidance portion. Specifically, the first avoidance portion A1 and the third avoidance portion may be arranged on the +W direction side of the element body 10, and the second avoidance portion A2 may be arranged on the −W direction side of the element body 10 rotated 180 degrees (i.e., the first avoidance portion A1 and the second avoidance portion A2 may be alternated). With this configuration, the magnetic flux direction is opposite between the first winding portion W1 and the fifth winding portion W5 adjacent to the second winding portion W2, or between the second winding portion W2 and the sixth winding portion W6 adjacent to the fourth winding portion W4, reducing magnetic flux bias and making magnetic saturation even less likely to occur. This improves the DC superposition characteristics of the multilayer inductor.

[0130] Although the above-described laminated inductor arrays 1B and 1C have been described as having three laminated inductors 1A arranged in an array, they may also have two arrays or four or more arrays.

[0131] Below, a demonstration test was carried out on the laminated inductor of the present disclosure.

[0132] <Demonstration Test 1 (Magnetic Field Analysis Simulation)> In Demonstration Test 1, simulation models of Example 1, which is the laminated inductor of the present disclosure, and Comparative Example 1, which is a conventional laminated inductor, were created and magnetic field analysis simulation was performed.

[0133] Example 1 As shown in Figure 2, the first winding portion W1 and the second winding portion W2 have an oval shape when viewed from above, and the first winding portion W1 and the second winding portion W2 have an avoidance portion A that avoids the fourth through hole T4 and two corner portions Z (see Figure 6).

[0134] More specific parameters are as follows: Size of element body 10 (see FIG. 2): L direction: 1.6 mm × W direction: 2.0 mm × T direction: 1.0 mm Width d of first winding portion (or second winding portion) in top view (see FIG. 2): 0.38 mm Height of first winding portion (or second winding portion) (height (thickness) of first and second winding portions W1, W2 in each stacking group in FIG. 3): 0.085 mm Interlayer gap of first winding portion (or second winding portion) (distance between stacking groups in each stacking group in FIG. 3): 0.01 mm Number of turns of first winding portion (or second winding portion): 2.5 turns

[0135] Comparative Example 1 As shown in FIG. 7A, the first winding portion and the second winding portion have a substantially rectangular shape when viewed from above, and the first winding portion and the second winding portion are provided with an avoidance portion that avoids the second through hole, an avoidance portion that avoids the third through hole, and an avoidance portion that avoids the fourth through hole, and five corners Z are provided (see FIG. 7A).

[0136] The magnetic field analysis simulation was performed using Femtet (registered trademark) manufactured by Murata Software Co., Ltd.

[0137] The results of a magnetic field analysis simulation of the laminated inductor of Comparative Example 1 are shown in Fig. 7. As shown in Fig. 7, magnetic saturation occurred in region R where magnetic flux concentrates at corner Z. On the other hand, the results of a magnetic field analysis simulation of the laminated inductor of Example 1 are shown in Fig. 6. As shown in Fig. 6, the number of corners was reduced compared to Fig. 7, and magnetic saturation was reduced.

[0138] <Demonstration Test 2 (DC Superimposition Current Simulation)> Next, the DC superimposition current was determined from the simulation results of the above-described Example 1 and Comparative Example 1. Fig. 9 is a graph showing the simulation results of the DC superimposition characteristics of Example 1 and Comparative Example 1.

[0139] 9, the DC superimposition current of the laminated inductor of Comparative Example 1 was 14 A, while that of the laminated inductor of Example 1 was 17.5 A. This result shows that the laminated inductor of Example 1 has a higher DC superimposition current.

[0140] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. The technical scope of the present disclosure also includes all modifications within the scope and meaning equivalent to the claims.

[0141] The laminated inductor and laminated inductor array of the present disclosure include the following aspects: <1> An element body having a rectangular bottom surface and including stacked magnetic layers, a first external electrode, a second external electrode, a third external electrode, and a fourth external electrode provided at four corners of the bottom surface of the element body, a first winding section in which a plurality of conductor layers arranged within the element body are connected in the stacking direction and having a winding axis in the stacking direction, a second winding section located above the first winding section in the stacking direction and in which a plurality of conductor layers arranged within the element body are connected in the stacking direction and having a winding axis in the stacking direction, a first through-hole electrically connecting one end of the first winding section to the first external electrode and extending in the stacking direction, a second through-hole electrically connecting the other end of the first winding section to the second external electrode and extending in the stacking direction, a third through-hole electrically connecting one end of the second winding section to the third external electrode and extending in the stacking direction, a fourth through hole electrically connecting the other end of the second winding portion and the fourth external electrode and extending in the lamination direction, wherein the first winding portion and the second winding portion have an oval shape in a top view, and the first winding portion and / or the second winding portion have an avoidance portion that avoids any one of the first through hole to the fourth through hole. <2> The multilayer inductor according to <1>, wherein the lengths of the through holes in the lamination direction satisfy the following relationship: length of the fourth through hole > length of the third through hole length of the third through hole > length of the second through hole length of the second through hole > length of the first through hole, and the avoidance portion avoids the fourth through hole. <3> The multilayer inductor according to <1> or <2>, wherein the winding axis of the first winding portion and the winding axis of the second winding portion are offset with respect to the center of the element body in a direction intersecting the lamination direction. <4> The laminated inductor according to <3>, wherein the direction of the deviation of the winding axis is a direction intersecting the lamination direction in a top view and is on the side where the avoidance portion is provided. <5> One end of the first winding portion and the first through hole are connected via a linear first connection portion, and the other end of the first winding portion and the second through hole are connected via a curved second connection portion,The laminated inductor according to any one of <1> to <4>, wherein one end of the second winding portion and the third through hole are connected via a curved third connection portion, and the other end of the second winding portion and the fourth through hole are connected via a linear fourth connection portion. <6> The laminated inductor according to <5>, wherein the curvature of the second connection portion and the third connection portion is smaller than the curvature of the first winding portion and the second winding portion. <7> The laminated inductor according to any one of <1> to <6>, wherein the second external electrode and the third external electrode are arranged along one side of the bottom surface of the rectangular shaped element body. <8> An element body having a rectangular bottom surface, in which magnetic layers are stacked in a stacking direction; a first external electrode, a second external electrode, a third external electrode, a fourth external electrode, a fifth external electrode, a sixth external electrode, a seventh external electrode, and an eighth external electrode provided along four sides of the bottom surface of the element body; a first winding section in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a second winding section located above the first winding section in the stacking direction and in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a third winding section in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a fourth winding section located above the third winding section in the stacking direction and in which a plurality of conductor layers are connected in the stacking direction and which has a winding axis in the stacking direction; a first through hole extending in the stacking direction and electrically connecting one end of the first winding section to the first external electrode; a second through hole electrically connecting the other end of the first winding portion and the second external electrode and extending in the stacking direction; a third through hole electrically connecting one end of the second winding portion and the third external electrode and extending in the stacking direction; a fourth through hole electrically connecting the other end of the second winding portion and the fourth external electrode and extending in the stacking direction; a fifth through hole electrically connecting one end of the third winding portion and the fifth external electrode and extending in the stacking direction; a sixth through hole electrically connecting the other end of the third winding portion and the sixth external electrode and extending in the stacking direction; a seventh through hole electrically connecting one end of the fourth winding portion and the seventh external electrode and extending in the stacking direction;and an eighth through hole electrically connecting the other end of the fourth winding portion and the eighth external electrode and extending in the stacking direction, wherein the third winding portion is arranged in a direction intersecting the stacking direction with respect to the first winding portion, and the fourth winding portion is arranged in a direction intersecting the stacking direction with respect to the second winding portion, wherein the first winding portion, the second winding portion, the third winding portion, and the fourth winding portion have an oval shape in a top view, wherein the first winding portion and / or the second winding portion are provided with a first avoidance portion that avoids any one of the first through hole to the fourth through hole, and wherein the third winding portion and / or the fourth winding portion are provided with a second avoidance portion that avoids any one of the fifth through hole to the eighth through hole. <9> A multilayer inductor array according to <8>, wherein the first avoidance portion and the second avoidance portion are not arranged along one side of the element body. <10> The laminated inductor array according to <8> or <9>, wherein the first winding portion and the third winding portion and / or the second winding portion and the fourth winding portion that are adjacent to each other in a direction intersecting the lamination direction are arranged alternately.

[0142] The present disclosure can be used for a laminated inductor and a laminated inductor array that have a reduced element area and further improved DC bias characteristics.

[0143] 1A Multilayer inductor 1B, 1C Multilayer inductor array 10 Element body 11 First main surface 12 Second main surface 13 First end surface 14 Second end surface 15 First side surface 16 Second side surface A Avoidance portion A1 First avoidance portion A2 Second avoidance portion C Coil C1 to C2 First coil to second coil J1 to J4 First connection portion to fourth connection portion E1 to E12 First external electrode to twelfth external electrode T1 to T12 First through hole to twelfth through hole V Via hole W1 First winding portion W2 Second winding portion ML Magnetic layer Z Corner portion DW Lead-out wiring P Winding axis O Center of element body

Claims

1. An element body having a rectangular bottom surface and having magnetic layers stacked thereon; a first external electrode, a second external electrode, a third external electrode, and a fourth external electrode provided at the four corners of the bottom surface of the element body; a first winding section in which a plurality of conductor layers arranged within the element body are connected in a stacking direction and has a winding axis in the stacking direction; a second winding section located higher in the stacking direction than the first winding section and in which a plurality of conductor layers arranged within the element body are connected in the stacking direction and has a winding axis in the stacking direction; a first through hole electrically connecting one end of the first winding section to the first external electrode and extending in the stacking direction; a second through hole electrically connecting the other end of the first winding section to the second external electrode and extending in the stacking direction; and a third through hole electrically connecting one end of the second winding section to the third external electrode and extending in the stacking direction. a fourth through hole electrically connecting the other end of the second winding portion and the fourth external electrode and extending in the stacking direction, wherein the first winding portion and the second winding portion have an oval shape in a top view, and the first winding portion and / or the second winding portion have an avoidance portion that avoids any one of the first through hole to the fourth through hole.

2. The laminated inductor of claim 1, wherein the lengths of the through holes in the lamination direction satisfy the following relationship: length of the fourth through hole > length of the third through hole length of the third through hole > length of the second through hole length of the second through hole > length of the first through hole, and the avoidance portion avoids the fourth through hole.

3. A laminated inductor according to claim 1 or 2, wherein the winding axis of said first winding portion and the winding axis of said second winding portion are offset from the center of said element body in a direction intersecting said lamination direction.

4. The laminated inductor according to claim 3, wherein the direction of the deviation of the winding axis is a direction intersecting the lamination direction in a top view and toward the side on which the avoidance portion is provided.

5. A multilayer inductor as claimed in any one of claims 1 to 4, wherein one end of the first winding portion and the first through hole are connected via a straight-line first connection portion, the other end of the first winding portion and the second through hole are connected via a curved second connection portion, one end of the second winding portion and the third through hole are connected via a curved third connection portion, and the other end of the second winding portion and the fourth through hole are connected via a straight-line fourth connection portion.

6. The laminated inductor according to claim 5, wherein the curvature of the second connection portion and the third connection portion is smaller than the curvature of the first winding portion and the second winding portion.

7. A multilayer inductor according to any one of claims 1 to 6, wherein the second external electrode and the third external electrode are arranged along one side of the bottom surface of the rectangular body.

8. An element body having a rectangular bottom surface and having magnetic layers stacked thereon; a first external electrode, a second external electrode, a third external electrode, a fourth external electrode, a fifth external electrode, a sixth external electrode, a seventh external electrode, and an eighth external electrode provided along the four sides of the bottom surface of the element body; a first winding section in which a plurality of conductor layers arranged within the element body are connected in a stacking direction and has a winding axis in the stacking direction; a second winding section located higher than the first winding section in the stacking direction, in which a plurality of conductor layers arranged within the element body are connected in the stacking direction and has a winding axis in the stacking direction; a third winding section in which a plurality of conductor layers are connected in the stacking direction and has a winding axis in the stacking direction; a fourth winding section located higher than the third winding section in the stacking direction, in which a plurality of conductor layers are connected in the stacking direction and has a winding axis in the stacking direction; a first through hole electrically connecting one end of the first winding section and the first external electrode and extending in the stacking direction; a second through hole electrically connecting the other end of the first winding portion and the second external electrode and extending in the stacking direction; a third through hole electrically connecting one end of the second winding portion and the third external electrode and extending in the stacking direction; a fourth through hole electrically connecting the other end of the second winding portion and the fourth external electrode and extending in the stacking direction; a fifth through hole electrically connecting one end of the third winding portion and the fifth external electrode and extending in the stacking direction; a sixth through hole electrically connecting the other end of the third winding portion and the sixth external electrode and extending in the stacking direction; a seventh through hole electrically connecting one end of the fourth winding portion and the seventh external electrode and extending in the stacking direction; and an eighth through hole electrically connecting the other end of the fourth winding portion and the eighth external electrode and extending in the stacking direction, the third winding portion is disposed in a direction intersecting the stacking direction with respect to the first winding portion, the fourth winding portion is disposed in a direction intersecting a stacking direction with respect to the second winding portion, the first winding portion, the second winding portion, the third winding portion and the fourth winding portion are elliptical in a top view, and the first winding portion and / or the second winding portion includes a first avoidance portion that avoids any one of the first through hole to the fourth through hole,A laminated inductor array, wherein the third winding portion and / or the fourth winding portion is provided with a second avoidance portion that avoids any one of the fifth through hole to the eighth through hole.

9. The laminated inductor array according to claim 8, wherein the first avoidance portion and the second avoidance portion are not disposed along one side of the element body.

10. A laminated inductor array as described in claim 8 or 9, wherein the first winding portion and the third winding portion and / or the second winding portion and the fourth winding portion that are adjacent to each other in a direction intersecting the lamination direction are arranged in a staggered manner.

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