Common mode noise filter
Patent Information
- Application Number
- PCT/JP2026/010163
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-25
- Filing Date
- 2026-03-16
- Publication Date
- 2026-10-01
Smart Images
Figure JP2026010163_01102026_PF_FP_ABST
Abstract
Description
Common Mode Noise Filter
[0001] The present disclosure generally relates to common mode noise filters, and more specifically to a common mode noise filter including a magnetic layer and a non-magnetic layer.
[0002] Conventionally, as a common mode noise filter, the electronic component (common mode noise filter) disclosed in Patent Document 1 is known.
[0003] In the electronic component described in Patent Document 1, a large area where a magnetic core can be arranged is secured in the region surrounded by the first coil conductor layer, the second coil conductor layer, and the third coil conductor layer.
[0004] Japanese Patent Application Laid-Open No. 2019-208032
[0005] Incidentally, in an electronic component (common mode noise filter) having the above configuration, a large area for arranging the magnetic core can be secured in the region surrounded by the first coil conductor layer, the second coil conductor layer, and the third coil conductor layer, so noise can be effectively removed. However, it is desired to suppress noise generated in a circuit with a configuration different from that of the conventional art.
[0006] The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a common mode noise filter that can suppress noise generated in a circuit with a configuration different from that of the conventional art.
[0007] A common-mode noise filter according to one aspect of the present disclosure comprises a first magnetic layer, a second magnetic layer, and a laminated portion. The first magnetic layer and the second magnetic layer are arranged in opposing directions. The laminated portion is arranged to fill the space between the first magnetic layer and the second magnetic layer. The laminated portion has, in order from the first magnetic layer in the opposing direction, a first non-magnetic layer, a third magnetic layer, and a second non-magnetic layer. The laminated portion further has four or more even-numbered coil conductors, each wound spirally around a central axis along the opposing direction and facing each other in the opposing direction. Each of the four or more even-numbered coil conductors is electrically connected to each other in different combinations to form two or more coils. The two or more coils include a first coil and a second coil. The first coil is formed to sandwich at least one of the two or more coil conductors included in the second coil in the opposing direction. The third magnetic layer is arranged such that the number of coil conductors arranged between the first magnetic layer and the third magnetic layer is the same as the number of coil conductors arranged between the second magnetic layer and the third magnetic layer.
[0008] According to this disclosure, noise generated in the circuit can be suppressed with a configuration different from conventional methods.
[0009] Figure 1 is an exploded perspective view of the common-mode noise filter according to this embodiment. Figure 2 is a plan view of the fourth layer and the fourth coil conductor of the common-mode noise filter according to this embodiment. Figure 3 is a plan view of the third layer and the third coil conductor of the common-mode noise filter according to this embodiment. Figure 4 is a plan view of the third magnetic layer and the second coil conductor of the common-mode noise filter according to this embodiment. Figure 5 is a plan view of the second layer and the first coil conductor of the common-mode noise filter according to this embodiment. Figure 6 is a cross-sectional view of the common-mode noise filter according to this embodiment. Figure 7 is a cross-sectional view of the common-mode noise filter of Modification 1. Figure 8 is another cross-sectional view of the common-mode noise filter of Modification 1. Figure 9 is a cross-sectional view of the common-mode noise filter of Modification 1 and Modification 4. Figure 10 is a cross-sectional view of the common-mode noise filter of Modification 4. Figure 11 is another cross-sectional view of the common-mode noise filter of Modification 1 and Modification 4. Figure 12 is a cross-sectional view of the common-mode noise filter of Modification 8. Figure 13 is a cross-sectional view of the common-mode noise filter of Modification 9.
[0010] The embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to these embodiments and modifications. Various modifications are possible depending on the design, etc., as long as they do not depart from the technical concept of the present disclosure.
[0011] The figures described in this disclosure are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the arrows indicating directions in the drawings are examples only and are not intended to define the direction of the common-mode noise filter 1. Also, the arrows indicating directions in the drawings are for illustrative purposes only and do not represent actual dimensions.
[0012] (Embodiment) The common-mode noise filter 1 according to this embodiment will be described below with reference to Figures 1 to 6.
[0013] (1) Schematic Figure 1 is an exploded perspective view of the common-mode noise filter 1 according to this embodiment. Figure 6 is a cross-sectional view of the common-mode noise filter 1 according to this embodiment. As shown in Figure 1, the common-mode noise filter 1 according to this embodiment comprises a first magnetic layer 21 and a second magnetic layer 25, and a laminated portion 26. The first magnetic layer 21 and the second magnetic layer 25 are arranged in opposing directions. The laminated portion 26 is arranged to fill the space between the first magnetic layer 21 and the second magnetic layer 25. The laminated portion 26 has, in order from the first magnetic layer 21 in the opposing direction, a first non-magnetic layer 22, a third magnetic layer 23, and a second non-magnetic layer 24. The laminated portion 26 further has four or more even-numbered coil conductors, each wound spirally around a central axis along the opposing direction and facing each other in the opposing direction. Each of the four or more even-numbered coil conductors is electrically connected to each other in different combinations to form two or more coils. The two or more coils include a first coil and a second coil. The first coil is formed to sandwich at least one of the two or more coil conductors included in the second coil in an opposing direction. As shown in Figure 6, the third magnetic layer 23 is arranged such that the number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is the same as the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23.
[0014] With this configuration, noise can be suppressed by arranging the third magnetic layer 23 such that the number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is the same as the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23. In other words, noise generated in the circuit can be suppressed with a configuration different from conventional designs.
[0015] (2) Configuration (2.1) Overall Configuration The common-mode noise filter 1 allows the differential mode component of a signal to pass through while attenuating common-mode noise. The common-mode noise filter 1 is mounted, for example, on a circuit board or electronic component of an electronic device.
[0016] The common-mode noise filter 1 according to this embodiment comprises a plurality of layers 20 (nine in the illustrated example), as shown in Figures 1 and 6. When distinguishing between the plurality of layers 20, they are referred to as layer 21a, layer 21b, first layer 22a, second layer 22b, third magnetic layer 23, third layer 24a, fourth layer 24b, layer 25a, and layer 25b. Of the plurality of layers 20, layers 21a and 21b form the first magnetic layer 21. Of the plurality of layers 20, layers 25a and 25b form the second magnetic layer 25. Of the plurality of layers 20, the first layer 22a and the second layer 22b form the first non-magnetic layer 22. Of the plurality of layers 20, the third layer 24a and the fourth layer 24b form the second non-magnetic layer 24. The first non-magnetic layer 22, the third magnetic layer 23, and the second non-magnetic layer 24 form a laminated portion 26.
[0017] In other words, as shown in Figures 1 and 6, the common-mode noise filter 1 according to this embodiment comprises a first magnetic layer 21, a second magnetic layer 25, and a laminated portion 26.
[0018] (2.2) The first magnetic layer and the second magnetic layer The first magnetic layer 21 and the second magnetic layer 25 include, for example, ferrite as a material.
[0019] As shown in Figure 1, the first magnetic layer 21 and the second magnetic layer 25 are arranged in opposing directions (up and down) to each other.
[0020] The first magnetic layer 21 includes layer 21a and layer 21b, as shown in Figure 1.
[0021] Layers 21a and 21b are arranged in the first magnetic layer 21 so as to be in contact with each other in opposing directions.
[0022] The second magnetic layer 25 includes layer 25a and layer 25b, as shown in Figure 1.
[0023] Layers 25a and 25b are arranged in the second magnetic layer 25 so as to be in contact with each other in opposing directions.
[0024] (2.3) Laminated section The laminated section 26 is arranged to fill the space between the first magnetic layer 21 and the second magnetic layer 25, as shown in Figure 6. The laminated section 26 has, in order from the first magnetic layer 21 in the opposing direction, a first non-magnetic layer 22, a third magnetic layer 23, and a second non-magnetic layer 24.
[0025] Furthermore, as shown in Figure 1, the laminated portion 26 further has a plurality (in this case, four) of coil conductors.
[0026] (2.3.1) Four Coil Conductors Each of the four coil conductors is a conductor formed in a spiral shape around a central axis aligned in opposite directions; in other words, a conductor wound in a spiral shape around a central axis aligned in opposite directions. More specifically, each of the four coil conductors has a shape in which the conductor is wound multiple times (in this case, three times) along a rectangular shape, as shown in Figures 2 to 5 described later. The length of each of the four coil conductors in the left-right direction is longer than the length of each of the corresponding coil conductors in the front-back direction. Each of the four coil conductors has three turns. In this disclosure, "turn" is a unit of angle indicating how far a conductor is wound, and one turn indicates that the conductor is wound around once (360°). That is, each of the four coil conductors has three turns. In other words, each of the four coil conductors has a shape in which the conductor is wound around a rectangular shape three times.
[0027] Each of the four coil conductors includes a first turn section, a second turn section, and a third turn section. Of these sections, the first turn section is located on the innermost side, and the third turn section is located on the outermost side.
[0028] In this embodiment, the four coil conductors are, as shown in Figure 1, the first coil conductor 3, the second coil conductor 4, the third coil conductor 5, and the fourth coil conductor 6, in order from closest to the first magnetic layer 21 in the opposing direction. Each of the four coil conductors faces each other in the opposing direction. That is, the first coil conductor 3, the second coil conductor 4, the third coil conductor 5, and the fourth coil conductor 6 face each other in the opposing direction, as shown in Figure 1.
[0029] Each of the four coil conductors is electrically connected to the others in different combinations to form two coils (first coil 2a and second coil 2b). In this embodiment, the first coil 2a is formed by electrically connecting the first coil conductor 3 and the fourth coil conductor 6 via a via hole 71, which will be described later. The second coil 2b is formed by electrically connecting the second coil conductor 4 and the third coil conductor 5 via a via hole 72, which will be described later.
[0030] One of the first coil 2a and the second coil 2b sandwiches the two coil conductors included in the other coil in opposing directions. In this embodiment, the first coil 2a, formed by the first coil conductor 3 and the fourth coil conductor 6, is formed to sandwich the second coil conductor 4 and the third coil conductor 5, which form the second coil 2b, in opposing directions, as shown in Figure 1.
[0031] (2.3.1.1) First coil conductor Figure 5 is a plan view of the second layer 22b and the first coil conductor 3 of the common-mode noise filter 1 according to this embodiment. The first coil conductor 3 is arranged so as to be sandwiched between the first layer 22a and the second layer 22b, as shown in Figure 6. As shown in Figures 5 and 6, the first turn portion of the first coil conductor 3 is the innermost circumference 311, and the third turn portion is the outermost circumference 313. The first end 33 of the first coil conductor 3 is electrically connected to a via hole 71, as shown in Figure 5. The second end 32 of the first coil conductor 3 is electrically connected to an external electrode (not shown).
[0032] (2.3.1.2) Second coil conductor Figure 4 is a plan view of the third magnetic layer 23 and the second coil conductor 4 of the common-mode noise filter 1 according to this embodiment. As shown in Figure 6, the second coil conductor 4 is arranged so as to be sandwiched between the second layer 22b and the third magnetic layer 23. As shown in Figures 4 and 6, the first turn portion of the second coil conductor 4 is the innermost circumference 411, and the third turn portion is the outermost circumference 413. Also, as shown in Figure 4, the first end 43 of the second coil conductor 4 is electrically connected to the via hole 72. The second end 42 of the second coil conductor 4 is electrically connected to the external electrode.
[0033] (2.3.1.3) Third Coil Conductor Figure 3 is a plan view of the third layer 24a and the third coil conductor 5 of the common-mode noise filter according to this embodiment. As shown in Figure 6, the third coil conductor 5 is positioned between the third magnetic layer 23 and the third layer 24a. As shown in Figures 3 and 6, the first turn portion of the third coil conductor 5 is the innermost circumference 511, and the third turn portion is the outermost circumference 513. The first end 53 of the third coil conductor 5 is electrically connected to the via hole 72, as shown in Figure 3. The second end 52 of the third coil conductor 5 is electrically connected to the external electrode.
[0034] (2.3.1.4) Fourth coil conductor Figure 2 is a plan view of the fourth layer 24b and the fourth coil conductor 6 of the common-mode noise filter 1 according to this embodiment. As shown in Figure 6, the fourth coil conductor 6 is positioned between the third layer 24a and the fourth layer 24b. As shown in Figures 2 and 6, the first turn portion of the fourth coil conductor 6 is the innermost circumference 611, and the third turn portion is the outermost circumference 613. The first end 63 of the fourth coil conductor 6 is electrically connected to the via hole 71, as shown in Figure 2. The second end 62 of the fourth coil conductor 6 is electrically connected to the external electrode.
[0035] (2.3.2) Details and arrangement of layers and coils in the laminated section (2.3.2.1) Second non-magnetic layer The second non-magnetic layer 24 is formed of a material including, for example, glass ceramic.
[0036] As shown in Figure 6, the second non-magnetic layer 24 includes a third layer 24a and a fourth layer 24b in order of proximity to the first magnetic layer 21 in the opposing direction.
[0037] When the laminated portion 26 is viewed from above, the fourth layer 24b is laminated so as to overlap the layer 25a.
[0038] As shown in Figures 2 and 6, the fourth coil conductor 6 is formed in the fourth layer 24b such that a portion of it is embedded in the surface closer to the first magnetic layer 21, out of two opposing surfaces along the opposing direction. In other words, when the laminated portion 26 is viewed from the side, the fourth layer 24b overlaps with a portion of the fourth coil conductor 6.
[0039] As shown in FIG. 6, the third layer 24a is laminated on the fourth layer 24b and the fourth coil conductor 6. In other words, the third layer 24a and the fourth layer 24b are arranged so as to sandwich the fourth coil conductor 6 therebetween. Further, when the laminated portion 26 is viewed from the top, the third layer 24a is laminated so as to overlap the fourth layer 24b. That is, as shown in FIG. 6, when the laminated portion 26 is viewed from the side, the third layer 24a overlaps a part of the fourth coil conductor 6.
[0040] As shown in FIG. 6, the third coil conductor 5 is formed in the third layer 24a such that a part of the third coil conductor 5 is embedded in the surface closer to the first magnetic layer 21 among the two surfaces opposing each other along the opposing direction. That is, when the laminated portion 26 is viewed from the side, the third layer 24a overlaps a part of the third coil conductor 5.
[0041] (2.3.2.2) Third Magnetic Layer The third magnetic layer 23 contains, for example, ferrite as a material.
[0042] As shown in FIG. 6, the third magnetic layer 23 is laminated on the third layer 24a and the third coil conductor 5. Further, when the laminated portion 26 is viewed from the top, the third magnetic layer 23 is laminated so as to overlap the third layer 24a. That is, as shown in FIG. 6, when the laminated portion 26 is viewed from the side, the third magnetic layer 23 overlaps a part of the third coil conductor 5.
[0043] As shown in FIG. 6, the second coil conductor 4 is formed in the third magnetic layer 23 such that a part of the second coil conductor 4 is embedded in the surface closer to the first magnetic layer 21 among the two surfaces opposing each other along the opposing direction. That is, when the laminated portion 26 is viewed from the side, the third magnetic layer 23 overlaps a part of the second coil conductor 4.
[0044] From the above, when the laminated portion 26 is viewed from the side, as shown in FIG. 6, the third magnetic layer 23 overlaps a part of the third coil conductor 5 and a part of the second coil conductor 4. That is, a part of the second coil conductor 4 and a part of the third coil conductor overlap a part of the third magnetic layer 23.
[0045] (2.3.2.3) First Non-Magnetic Layer The first non-magnetic layer 22 is formed of a material containing, for example, glass ceramic.
[0046] The first non-magnetic layer 22 includes a first layer 22a and a second layer 22b in the order of proximity to the first magnetic layer 21 in the opposing direction.
[0047] As shown in FIG. 6, the second layer 22b is laminated on the third magnetic layer 23 and the second coil conductor 4. Further, when the laminated portion 26 is viewed from the top, the second layer 22b is laminated so as to overlap the third magnetic layer 23. That is, as shown in FIG. 6, when the laminated portion 26 is viewed from the side, the second layer 22b overlaps a part of the second coil conductor 4.
[0048] As shown in FIG. 6, the first coil conductor 3 is formed on the second layer 22b such that a part of the first coil conductor 3 is embedded in the surface closer to the first magnetic layer 21 among the two surfaces opposing each other along the opposing direction. That is, when the laminated portion 26 is viewed from the side, the second layer 22b overlaps a part of the first coil conductor 3.
[0049] From the above, when the laminated portion 26 is viewed from the side, the second layer 22b overlaps a part of the second coil conductor 4 and a part of the first coil conductor 3. That is, when the laminated portion 26 is viewed from the side, a part of the first coil conductor 3 and a part of the second coil conductor 4 overlap the second layer 22b.
[0050] As shown in FIG. 6, the first layer 22a is laminated on the second layer 22b and the first coil conductor 3. In other words, the first layer 22a and the second layer 22b are arranged so as to sandwich the first coil conductor 3. Further, when the laminated portion 26 is viewed from the top, the first layer 22a is laminated so as to overlap the second layer 22b. That is, as shown in FIG. 6, when the laminated portion 26 is viewed from the side, the first layer 22a overlaps a part of the first coil conductor 3.
[0051] When the laminated portion 26 is viewed from the top, the first layer 22a is laminated such that the first magnetic layer 21 overlaps the first layer 22a.
[0052] (2.3.3) Relationship between coil conductors and the third magnetic layer Here, the third magnetic layer 23 is arranged such that the number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is the same as the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23. That is, in this embodiment, the second coil conductor 4 and the third coil conductor 5 are arranged so as to sandwich the third magnetic layer 23. The number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is 2. Also, the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23 is 2. In other words, the number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is the same as the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23.
[0053] (2.3.4) Beer Halls Beer halls 71 and 72 are provided in the stacked section 26, as shown in Figure 6.
[0054] The via holes 71 are formed in the second layer 22b, the third magnetic layer 23, and the third layer 24a by a laser. More specifically, the via holes 71 are circular holes in the second layer 22b, the third magnetic layer 23, and the third layer 24a, having a central axis that is aligned with the direction in which the laminated portion 26 is viewed from above (see Figures 3 to 5). When the laminated portion 26 is viewed from above, the via holes 71 are positioned to the left of the center along the left-right direction. The inner surface portion 711 of the via holes 71 is copper-plated (not shown) and electrically connects the first coil conductor 3 and the fourth coil conductor 6.
[0055] The via holes 72 are formed in the third magnetic layer 23 by a laser. More specifically, the via holes 72 are circular holes in the third magnetic layer 23 that have a central axis with an axis in the direction along the opposing direction when the laminated portion 26 is viewed from above (see Figure 4). When the laminated portion 26 is viewed from above, the via holes 72 are located to the right of the center along the left-right direction. The inner surface portion 721 of the via holes 72 is copper-plated (not shown) and electrically connects the second coil conductor 4 and the third coil conductor 5.
[0056] (3) Advantages As described above, the common-mode noise filter 1 according to this embodiment comprises a first magnetic layer 21 and a second magnetic layer 25, and a laminated portion 26. The first magnetic layer 21 and the second magnetic layer 25 are arranged in opposing directions facing each other. The laminated portion 26 is arranged to fill the space between the first magnetic layer 21 and the second magnetic layer 25. The laminated portion 26 has, in order from the first magnetic layer 21 in the opposing direction, a first non-magnetic layer 22, a third magnetic layer 23, and a second non-magnetic layer 24. The laminated portion 26 further has four or more even-numbered coil conductors, each wound spirally around a central axis along the opposing direction and facing each other in the opposing direction. Each of the four or more even-numbered coil conductors is electrically connected to each other in different combinations to form two or more coils. The two or more coils include a first coil and a second coil. The first coil is formed to sandwich at least one of the two or more coil conductors included in the second coil in the opposing direction. As shown in Figure 6, the third magnetic layer 23 is arranged such that the number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is the same as the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23.
[0057] With this configuration, noise can be suppressed by arranging the third magnetic layer 23 such that the number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is the same as the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23. In other words, noise generated in the circuit can be suppressed with a configuration different from conventional designs.
[0058] (4) Modifications The following are examples of modifications. The modifications described below can be applied in appropriate combination with the above embodiments.
[0059] Figure 7 is a cross-sectional view of the common-mode noise filter 1A of Modification 1. Figure 8 is another cross-sectional view of the common-mode noise filter 1B of Modification 1. Figure 9 is a cross-sectional view of the common-mode noise filter 1C of Modification 1 and Modification 4, which will be described later. Figure 10 is a cross-sectional view of the common-mode noise filter 1D of Modification 4. Figure 11 is another cross-sectional view of the common-mode noise filter 1E of Modification 1 and Modification 4, which will be described later.
[0060] (4.1) Modification 1 In the above embodiment, when the laminated portion 26 is viewed from the side, a part of the second coil conductor 4 and a part of the third coil conductor 5 overlap with the third magnetic layer 23, but the configuration is not limited to this. When the laminated portion 26 is viewed from the side, the entirety of the second coil conductor 4 may overlap with the third magnetic layer 23.
[0061] Furthermore, when the laminated portion 26 is viewed from the side, the entirety of the second coil conductor 4 does not have to overlap with the third magnetic layer 23. More specifically, when the laminated portion 26 is viewed from the side, as shown in Figure 7, the entirety of the second coil conductor 4A does not have to overlap with the third magnetic layer 23. When the laminated portion 26 is viewed from the side, as shown in Figure 8, the entirety of the second coil conductor 4B does not have to overlap with the third magnetic layer 23. When the laminated portion 26 is viewed from the side, as shown in Figure 9, the entirety of the second coil conductor 4C does not have to overlap with the third magnetic layer 23. When the laminated portion 26 is viewed from the side, as shown in Figure 11, the entirety of the second coil conductor 4E does not have to overlap with the third magnetic layer 23. Note that the first coil conductor 3A and the fourth coil conductor 6A shown in Figure 7 have the same configuration as the first coil conductor 3 and the fourth coil conductor 6 shown in Figure 6, respectively. Furthermore, the first coil conductor 3B and the fourth coil conductor 6B shown in Figure 8 have the same configuration as the first coil conductor 3 and the fourth coil conductor 6 shown in Figure 6, respectively.
[0062] Furthermore, when the laminated portion 26 is viewed from the side, the entirety of the third coil conductor 5 may overlap with the third magnetic layer 23. More specifically, when the laminated portion 26 is viewed from the side, the entirety of the third coil conductor 5B may overlap with the third magnetic layer 23, as shown in Figure 8. When the laminated portion 26 is viewed from the side, the entirety of the third coil conductor 5E may overlap with the third magnetic layer 23, as shown in Figure 11.
[0063] Furthermore, when the laminated portion 26 is viewed from the side, it is not necessary for all of the third coil conductor 5 to overlap with the third magnetic layer 23. More specifically, when the laminated portion 26 is viewed from the side, as shown in Figure 7, it is not necessary for all of the third coil conductor 5A to overlap with the third magnetic layer 23. When the laminated portion 26 is viewed from the side, as shown in Figure 9, it is not necessary for all of the third coil conductor 5C to overlap with the third magnetic layer 23.
[0064] In other words, at least a portion of the second coil conductor 4 and at least a portion of the third coil conductor 5 may overlap with the third magnetic layer 23. Also, at least a portion of the second coil conductor 4 or at least a portion of the third coil conductor 5 may overlap with the third magnetic layer 23.
[0065] (4.2) Modification 2 When the laminated portion 26 is viewed from the side, the third layer 24a and the fourth layer 24b are configured to overlap with a part of the fourth coil conductor 6, but the configuration is not limited to this.
[0066] When the laminated portion 26 is viewed from the side, either the third layer 24a or the fourth layer 24b may overlap with the entirety of the fourth coil conductor 6.
[0067] (4.3) Modification 3 When the laminated portion 26 is viewed from the side, the first layer 22a and the second layer 22b are configured to overlap with a part of the first coil conductor 3, but the configuration is not limited to this.
[0068] When the laminated portion 26 is viewed from the side, either the first layer 22a or the second layer 22b may overlap with the entirety of the first coil conductor 3.
[0069] (4.4) Modification 4 In the above embodiment, the second non-magnetic layer 24 has a configuration that includes two layers (third layer 24a and fourth layer 24b) as shown in Figure 6, but it is not limited to this configuration. The second non-magnetic layer 24 may be a single layer as shown in Figures 9 to 11. Also, the second non-magnetic layer 24 may include three or more layers.
[0070] Furthermore, in the above embodiment, the first non-magnetic layer 22 is configured to include two layers (first layer 22a, second layer 22b), but it is not limited to this configuration. The first non-magnetic layer 22 may be a single layer, as shown in Figures 9 to 11. Also, the first non-magnetic layer 22 may include three or more layers.
[0071] Details of the case where the first non-magnetic layer 22 and the second non-magnetic layer 24 are a single layer structure are described below.
[0072] In the above embodiment, the fourth coil conductor 6 is sandwiched between the third layer 24a and the fourth layer 24b, but in Modification 4, it is sandwiched between the second non-magnetic layer 24 and the second magnetic layer 25. In other words, the fourth coil conductor 6 is arranged to be in contact with the second magnetic layer 25.
[0073] Furthermore, in Modification 4, instead of being sandwiched between the first layer 22a and the second layer 22b in the above embodiment, the first coil conductor 3 is sandwiched between the first magnetic layer 21 and the first non-magnetic layer 22. In other words, the first coil conductor 3 is arranged to be in contact with the first magnetic layer 21.
[0074] In other words, in modified example 4, when the laminated portion 26 is viewed from the side, the entirety of the first coil conductor 3 overlaps the first non-magnetic layer 22. Also, the entirety of the fourth coil conductor 6 overlaps the second non-magnetic layer 24.
[0075] Figure 9 is a diagram showing the application of Modification 4 to Figure 7 in Modification 1. That is, in Figure 9, the first coil conductor 3C is sandwiched between layer 21b and the first non-magnetic layer 22. The fourth coil conductor 6C is sandwiched between layer 25a and the second non-magnetic layer 24.
[0076] Furthermore, Figure 10 is a diagram showing the modified version 4 applied to Figure 6 in the above embodiment. In Figure 10, the first coil conductor 3D is sandwiched between layer 21b and the first non-magnetic layer 22. Also, the fourth coil conductor 6D is sandwiched between layer 25a and the second non-magnetic layer 24. Note that the second coil conductor 4D and the third coil conductor 5D shown in Figure 10 have the same configuration as the second coil conductor 4 and the third coil conductor 5 shown in Figure 6, respectively.
[0077] Furthermore, Figure 11 is a diagram in which Modification 4 is applied to Figure 8 in Modification 1. That is, in Figure 11, the first coil conductor 3E is sandwiched between layer 21b and the first non-magnetic layer 22. Also, the fourth coil conductor 6E is sandwiched between layer 25a and the second non-magnetic layer 24.
[0078] (4.5) Modification 5 In the above embodiment, the first magnetic layer 21 and the second magnetic layer 25 are configured to include two layers (layer 21a and layer 21b and layer 25a and layer 25b) as shown in Figure 6, but the configuration is not limited to this. The first magnetic layer 21 and the second magnetic layer 25 may be one layer or may include three or more layers.
[0079] Furthermore, in the above embodiment, the third magnetic layer 23 is a single-layer structure as shown in Figure 6, but the configuration is not limited to this. The third magnetic layer 23 may include two or more layers.
[0080] (4.6) Modification 6 In the above embodiment, one of the two coils (first coil 2a and second coil 2b) (first coil 2a) is formed to sandwich the two coil conductors (second coil conductor 4 and third coil conductor 5) included in the other coil (second coil 2b) in opposing directions. However, the embodiment is not limited to this configuration.
[0081] One of the two coils may be formed so as to sandwich one of the two coil conductors contained in the other coil in an opposing direction. In other words, one of the two coils is formed so as to sandwich at least one of the two coil conductors contained in the other coil in an opposing direction.
[0082] For example, a first coil may be formed by electrically connecting a first coil conductor 3 and a third coil conductor 5 via a via hole, and a second coil may be formed by electrically connecting a second coil conductor 4 and a fourth coil conductor 6 via another via hole.
[0083] (4.7) Modification 7 In the above embodiment, each of the four coil conductors (first coil conductor 3, second coil conductor 4, third coil conductor 5, fourth coil conductor 6) is connected to each other via via holes in different combinations to form two coils (first coil 2a and second coil 2b). However, the configuration is not limited to this. Each of the four coil conductors may be connected to each other via via pads in different combinations to form two coils (first coil 2a and second coil 2b).
[0084] In other words, each of the four coil conductors (first coil conductor 3, second coil conductor 4, third coil conductor 5, and fourth coil conductor 6) is electrically connected to each other in different combinations to form two coils (first coil 2a and second coil 2b).
[0085] (4.8) Modification 8 Figure 12 is a cross-sectional view of the common-mode noise filter 1F of Modification 8. In the above embodiment, the laminated portion 26 may further include a magnetic shaft 8, as shown in Figure 12.
[0086] The magnetic axis 8 includes, for example, ferrite as its material.
[0087] The magnetic shaft 8 is formed, for example, in a cylindrical shape. The magnetic shaft 8 may also be conical, rectangular, polygonal prism, or polygonal pyramidal.
[0088] As shown in Figure 12, the magnetic shaft 8 is formed to connect the first magnetic layer 21 and the second magnetic layer 25. The magnetic shaft 8 is also formed on the central axis around which the four coil conductors (first coil conductor 3, second coil conductor 4, third coil conductor 5, and fourth coil conductor 6) are wound.
[0089] (4.9) Modification 9 In the above embodiment, the laminated portion 26 has a configuration having four coil conductors (first coil conductor 3, second coil conductor 4, third coil conductor 5, fourth coil conductor 6), but is not limited to this configuration. The laminated portion 26 may have a configuration having six coil conductors (first coil conductor 91, second coil conductor 92, third coil conductor 93, fourth coil conductor 94, fifth coil conductor 95, sixth coil conductor 96), as shown in Figure 13. The laminated portion 26 may have a configuration having eight coil conductors. In other words, the laminated portion 26 may have a configuration that includes four or more even-numbered coil conductors.
[0090] Furthermore, if the laminated portion 26 has four or more even-numbered coil conductors, each of the four or more even-numbered coil conductors is electrically connected to each other in different combinations, forming two or more coils. In addition, the first coil of the two or more coils sandwiches at least one of the two or more coil conductors included in the second coil of the two or more coils in an opposing direction.
[0091] Here, the configuration of the common-mode noise filter 1G when the laminated portion 26 has six coil conductors (first coil conductor 91, second coil conductor 92, third coil conductor 93, fourth coil conductor 94, fifth coil conductor 95, and sixth coil conductor 96) will be explained using Figure 13. Figure 13 is a cross-sectional view of the common-mode noise filter 1G of modified example 9.
[0092] The common-mode noise filter 1G in modified example 9 comprises a plurality of layers 20 (11 in the illustrated example), as shown in Figure 13. When distinguishing between the plurality of layers 20, they are referred to as layer 21a, layer 21b, first layer 22x, second layer 22y, third layer 22z, third magnetic layer 23, fourth layer 24x, fifth layer 24y, sixth layer 24z, layer 25a, and layer 25b. Of the plurality of layers 20, layers 21a and 21b form the first magnetic layer 21. Of the plurality of layers 20, layers 25a and 25b form the second magnetic layer 25. Of the plurality of layers 20, the first layer 22x, second layer 22y, and third layer 22z form the first non-magnetic layer 22. Of the plurality of layers 20, the fourth layer 24x, fifth layer 24y, and sixth layer 24z form the second non-magnetic layer 24. The first non-magnetic layer 22, the third magnetic layer 23, and the second non-magnetic layer 24 form a laminated portion 26.
[0093] The laminated section 26 has a plurality (in this case, six) of coil conductors (first coil conductor 91, second coil conductor 92, third coil conductor 93, fourth coil conductor 94, fifth coil conductor 95, and sixth coil conductor 96).
[0094] Each of the six coil conductors is a conductor formed in a spiral shape around a central axis aligned in opposite directions; in other words, a conductor wound in a spiral shape around a central axis aligned in opposite directions. More specifically, each of the six coil conductors is shaped by winding the conductor multiple times (in this case, three times) along a rectangular shape. The length of each of the six coil conductors in the left-right direction is longer than the length of each corresponding coil conductor in the front-back direction. The number of turns of each of the six coil conductors is, for example, three turns. In this disclosure, "turn" is a unit of angle indicating how far a conductor is wound, where one turn indicates that the conductor is wound around once (360°). That is, the number of turns of each of the six coil conductors is three. In other words, each of the six coil conductors is shaped by winding the conductor around a rectangular shape three times.
[0095] Each of the six coil conductors includes a first-turn section, a second-turn section, and a third-turn section. Of these sections, the first-turn section is located on the innermost side, and the third-turn section is located on the outermost side.
[0096] In the modified example 9, the six coil conductors are, as shown in Figure 13, the first coil conductor 91, the second coil conductor 92, the third coil conductor 93, the fourth coil conductor 94, the fifth coil conductor 95, and the sixth coil conductor 96, in order from closest to the first magnetic layer 21 in the opposing direction. Each of the six coil conductors faces each other in the opposing direction. That is, the first coil conductor 91, the second coil conductor 92, the third coil conductor 93, the fourth coil conductor 94, the fifth coil conductor 95, and the sixth coil conductor 96 face each other in the opposing direction, as shown in Figure 1.
[0097] Each of the six coil conductors is electrically connected to the others in different combinations, thereby forming three coils (the first coil 2c, the second coil 2d, and the third coil 2e).
[0098] In modified example 9, the first coil 2c is formed by electrically connecting the first coil conductor 91 and the fourth coil conductor 94 via a via hole 75, as shown in Figure 13.
[0099] Furthermore, as shown in Figure 13, the second coil 2d is formed by electrically connecting the second coil conductor 92 and the fifth coil conductor 95 via a via hole 73, which will be described later.
[0100] Furthermore, as shown in Figure 13, the third coil 2e is formed by electrically connecting the third coil conductor 93 and the sixth coil conductor 96 via a via hole 74, which will be described later.
[0101] As shown in Figure 13, one of the three coils (for example, the first coil 2c) sandwiches one of the two coil conductors (for example, the second coil conductor 92 and the fifth coil conductor 95, and the third coil conductor 93 and the sixth coil conductor 96) contained in each of the remaining coils (for example, the second coil conductor 92 and the third coil conductor 93) in opposite directions.
[0102] As shown in Figure 13, the first coil conductor 91 is positioned between the first layer 22x and the second layer 22y. One end of the first coil conductor 91 is electrically connected to the via hole 75. The remaining end of the first coil conductor 91 is electrically connected to the external electrode.
[0103] As shown in Figure 13, the second coil conductor 92 is positioned between the second layer 22y and the third layer 22z. One end of the second coil conductor 92 is electrically connected to the via hole 73. The remaining end of the second coil conductor 92 is electrically connected to the external electrode.
[0104] As shown in Figure 13, the third coil conductor 93 is positioned between the third layer 22z and the third magnetic layer 23. One end of the third coil conductor 93 is electrically connected to the via hole 74. The remaining end of the third coil conductor 93 is electrically connected to the external electrode.
[0105] As shown in Figure 6, the fourth coil conductor 94 is positioned between the third magnetic layer 23 and the fourth layer 24x. One end of the fourth coil conductor 94 is electrically connected to the via hole 75. The remaining end of the fourth coil conductor 94 is electrically connected to the external electrode.
[0106] As shown in Figure 13, the fifth coil conductor 95 is positioned between the fourth layer 24x and the fifth layer 24y. One end of the fifth coil conductor 95 is electrically connected to the via hole 73. The remaining end of the fifth coil conductor 95 is electrically connected to the external electrode.
[0107] As shown in Figure 13, the sixth coil conductor 96 is positioned between the fifth layer 24y and the sixth layer 24z. One end of the sixth coil conductor 96 is electrically connected to the via hole 74. The remaining end of the sixth coil conductor 96 is electrically connected to the external electrode.
[0108] As shown in Figure 13, the second non-magnetic layer 24 includes a fourth layer 24x, a fifth layer 24y, and a sixth layer 24z in order of proximity to the first magnetic layer 21 in the opposing direction.
[0109] When the laminated portion 26 is viewed from above, the sixth layer 24z is laminated so as to overlap with layer 25a.
[0110] As shown in Figure 13, the sixth coil conductor 96 is formed in the sixth layer 24z such that a portion of it is embedded in the surface closer to the first magnetic layer 21, out of two opposing surfaces along the opposing direction. In other words, when the laminated portion 26 is viewed from the side, the sixth layer 24z overlaps with a portion of the sixth coil conductor 96.
[0111] As shown in Figure 13, the fifth layer 24y is laminated on the sixth layer 24z and the sixth coil conductor 96. In other words, the fifth layer 24y and the sixth layer 24z are arranged so as to sandwich the sixth coil conductor 96. Also, when the laminated portion 26 is viewed from above, the fifth layer 24y is laminated so as to overlap the sixth layer 24z. That is, as shown in Figure 13, when the laminated portion 26 is viewed from the side, the fifth layer 24y overlaps with a part of the sixth coil conductor 96.
[0112] As shown in Figure 13, the fifth coil conductor 95 is formed in the fifth layer 24y such that a portion of it is embedded in the surface closer to the first magnetic layer 21, out of two opposing surfaces along the opposing direction. In other words, when the laminated portion 26 is viewed from the side, the fifth layer 24y overlaps with a portion of the fifth coil conductor 95.
[0113] As shown in Figure 13, the fourth layer 24x is laminated on the fifth layer 24y and the fifth coil conductor 95. In other words, the fourth layer 24x and the fifth layer 24y are arranged so as to sandwich the fifth coil conductor 95. Also, when the laminated portion 26 is viewed from above, the fourth layer 24x is laminated so as to overlap the fifth layer 24y. That is, as shown in Figure 13, when the laminated portion 26 is viewed from the side, the fourth layer 24x overlaps with a part of the fifth coil conductor 95.
[0114] As shown in Figure 13, the fourth coil conductor 94 is formed in the fourth layer 24x such that a portion of it is embedded in the surface closer to the first magnetic layer 21, out of two opposing surfaces along the opposing direction. In other words, when the laminated portion 26 is viewed from the side, the fourth layer 24x overlaps with a portion of the fourth coil conductor 94.
[0115] As shown in Figure 13, the third magnetic layer 23 is laminated on the fourth layer 24x and the fourth coil conductor 94. When the laminated portion 26 is viewed from above, the third magnetic layer 23 is laminated so as to overlap the fourth layer 24x. In other words, as shown in Figure 13, when the laminated portion 26 is viewed from the side, the third magnetic layer 23 overlaps with a part of the fourth coil conductor 94.
[0116] As shown in Figure 13, the third coil conductor 93 is formed in the third magnetic layer 23 such that a portion of it is embedded in the surface closer to the first magnetic layer 21 of the two opposing surfaces in the opposing direction. In other words, when the laminated portion 26 is viewed from the side, the third magnetic layer 23 overlaps with a portion of the third coil conductor 93.
[0117] The first non-magnetic layer 22 has a first layer 22x, a second layer 22y, and a third layer 22z, arranged in order from closest to the first magnetic layer 21 in the opposing direction.
[0118] As shown in Figure 13, the third layer 22z is laminated on the third magnetic layer 23 and the third coil conductor 93. In other words, the third magnetic layer 23 and the third layer 22z are arranged so as to sandwich the third coil conductor 93. When the laminated portion 26 is viewed from above, the third layer 22z is laminated so as to overlap the third magnetic layer 23. That is, as shown in Figure 13, when the laminated portion 26 is viewed from the side, the third layer 22z overlaps with a part of the third coil conductor 93.
[0119] As shown in Figure 13, the third layer 22z has a second coil conductor 92 formed on it such that a portion of it is embedded in the surface closer to the first magnetic layer 21, out of two opposing surfaces in the opposing direction. In other words, when the laminated portion 26 is viewed from the side, the third layer 22z overlaps with a portion of the second coil conductor 92.
[0120] As shown in Figure 13, the second layer 22y is laminated on the third layer 22z and the second coil conductor 92. In other words, the second layer 22y and the third layer 22z are arranged so as to sandwich the second coil conductor 92. Also, when the laminated portion 26 is viewed from above, the second layer 22y is laminated so as to overlap the third layer 22z. That is, as shown in Figure 13, when the laminated portion 26 is viewed from the side, the second layer 22y overlaps with a part of the second coil conductor 92.
[0121] As shown in Figure 13, the first coil conductor 91 is formed in the second layer 22y such that a portion of it is embedded in the surface closer to the first magnetic layer 21, out of two opposing surfaces along the opposing direction. In other words, when the laminated portion 26 is viewed from the side, the second layer 22y overlaps with a portion of the first coil conductor 91.
[0122] As shown in Figure 13, the first layer 22x is laminated on the second layer 22y and the first coil conductor 91. In other words, the first layer 22x and the second layer 22y are arranged so as to sandwich the first coil conductor 91. When the laminated portion 26 is viewed from above, the first layer 22x is laminated so as to overlap the second layer 22y. That is, as shown in Figure 13, when the laminated portion 26 is viewed from the side, the first layer 22x overlaps with a part of the first coil conductor 91.
[0123] In modified example 9, the third coil conductor 93 and the fourth coil conductor 94 are arranged so as to sandwich the third magnetic layer 23. The number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is three. Also, the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23 is three. In other words, the number of coil conductors arranged between the first magnetic layer 21 and the third magnetic layer 23 is the same as the number of coil conductors arranged between the second magnetic layer 25 and the third magnetic layer 23.
[0124] As shown in Figure 13, beer holes 73, 74, and 75 are provided in the stacked section 26.
[0125] The via holes 73 are formed in the third layer 22z, the third magnetic layer 23, and the fourth layer 24x by a laser. More specifically, the via holes 71 are circular holes in the third layer 22z, the third magnetic layer 23, and the fourth layer 24x, having a central axis that is aligned with the direction in which the laminated portion 26 is viewed from above. The via holes 73 are located to the left of the center in the left-right direction when the laminated portion 26 is viewed from above. The inner surface of the via holes 73 is coated with copper (not shown) and electrically connects the first coil conductor 91 and the fourth coil conductor 94.
[0126] The via holes 74 are formed in the third magnetic layer 23, the fourth layer 24x, and the fifth layer 24y by a laser. More specifically, the via holes 74 are circular holes in the third magnetic layer 23, the fourth layer 24x, and the fifth layer 24y, having a central axis that is aligned with the direction in which the layers are opposed when the laminated portion 26 is viewed from above. The via holes 74 are located in the center along the left-right direction when the laminated portion 26 is viewed from above. The inner surface of the via holes 74 is copper-plated (not shown) and electrically connects the second coil conductor 92 and the fifth coil conductor 95.
[0127] The via holes 75 are formed in the second layer 22y, the third layer 22z, and the third magnetic layer 23 by a laser. More specifically, the via holes 75 are circular holes in the second layer 22y, the third layer 22z, and the third magnetic layer 23, having a central axis that is aligned with the direction in which the laminated portion 26 is viewed from above. When the laminated portion 26 is viewed from above, the via holes 75 are positioned to the right of the center along the left-right direction. The inner surface of the via holes 75 is coated with copper (not shown), and electrically connects the third coil conductor 93 and the sixth coil conductor 96.
[0128] (Summary) As described above, the common-mode noise filter of the first embodiment (1; 1A; 1B; 1C; 1D; 1E; 1F; 1G) comprises a first magnetic layer (21) and a second magnetic layer (25), and a laminated portion (26). The first magnetic layer (21) and the second magnetic layer (25) are arranged in opposing directions facing each other. The laminated portion (26) is arranged to fill the space between the first magnetic layer (21) and the second magnetic layer (25). The laminated portion (26) has, in order from the first magnetic layer (21) in the opposing direction, a first non-magnetic layer (22), a third magnetic layer (23), and a second non-magnetic layer (24). The laminated portion (26) further has four or more even-numbered coil conductors, each spirally wound around a central axis along the opposing direction and facing each other in the opposing direction. Each of four or more even-numbered coil conductors is electrically connected to each other in different combinations to form two or more coils. The two or more coils include a first coil (2a) and a second coil (2b). The first coil (2a) is formed to sandwich at least one of the two or more coil conductors included in the second coil (2b) in an opposing direction. The third magnetic layer (23) is arranged such that the number of coil conductors arranged between the first magnetic layer (21) and the third magnetic layer (23) is the same as the number of coil conductors arranged between the second magnetic layer (25) and the third magnetic layer (23).
[0129] According to this embodiment, noise can be suppressed by arranging the third magnetic layer (23) such that the number of coil conductors arranged between the first magnetic layer (21) and the third magnetic layer (23) is the same as the number of coil conductors arranged between the second magnetic layer (25) and the third magnetic layer (23). In other words, noise generated in the circuit can be suppressed with a configuration different from the conventional one.
[0130] In the second embodiment of the common-mode noise filter (1; 1A; 1B; 1C; 1D; 1E; 1F), the four or more even-numbered coil conductors are four coil conductors. The four coil conductors, in order from closest to the first magnetic layer (21) in the opposing direction, are the first coil conductor (3; 3A; 3B; 3C; 3D; 3E), the second coil conductor (4; 4A; 4B; 4C; 4D; 4E), the third coil conductor (5; 5A; 5B; 5C; 5D; 5E), and the fourth coil conductor (6; 6A; 6B; 6C; 6D; 6E).
[0131] According to this embodiment, noise generated in the circuit can be suppressed in a configuration different from conventional ones by using four coil conductors.
[0132] In the third embodiment of the common-mode noise filter (1C; 1D; 1E), in the first or second embodiment, the first coil conductor (3C; 3D; 3E) is arranged in contact with the first magnetic layer (21). The fourth coil conductor (6C; 6D; 6E) is arranged in contact with the second magnetic layer (25). The second coil conductor (4C; 4D; 4E) and the third coil conductor (5C; 5D; 5E) are arranged to sandwich the third magnetic layer (23).
[0133] According to this embodiment, the arrangement of the four coil conductors and the arrangement of the third magnetic layer (23) makes it possible to suppress noise generated in the circuit in a configuration different from the conventional one.
[0134] In the fourth embodiment of the common-mode noise filter (1C; 1D), when the laminated portion (26) is viewed from the side, at least a portion of the second coil conductor (4C; 4D) and at least a portion of the third coil conductor (5C; 5D) overlap with the third magnetic layer (23).
[0135] According to this embodiment, the arrangement of the four coil conductors and the arrangement of the third magnetic layer (23) makes it possible to suppress noise generated in the circuit in a configuration different from the conventional one.
[0136] In the fifth embodiment of the common-mode noise filter (1E), when the laminated portion (26) is viewed from the side, at least a portion of the second coil conductor (4E) or at least a portion of the third coil conductor (5E) overlaps with the third magnetic layer (23).
[0137] According to this embodiment, the arrangement of the four coil conductors and the arrangement of the third magnetic layer (23) makes it possible to suppress noise generated in the circuit in a configuration different from the conventional one.
[0138] The common-mode noise filter (1; 1A; 1B; 1F) in the sixth embodiment, in the first or second embodiment, the first non-magnetic layer (22) includes a first layer (22a) and a second layer (22b) in order of proximity to the first magnetic layer (21) in the opposing direction. The second non-magnetic layer (24) includes a third layer (24a) and a fourth layer (24b) in order of proximity to the first magnetic layer (21) in the opposing direction. The first layer (22a) and the second layer (22b) are arranged to sandwich the first coil conductor (3; 3A; 3B). The third layer (24a) and the fourth layer (24b) are arranged to sandwich the fourth coil conductor (6; 6A; 6B). The second coil conductor (4; 4A; 4B) and the third coil conductor (5; 5A; 5B) are arranged to sandwich the third magnetic layer (23).
[0139] According to this embodiment, the arrangement of the four coil conductors and the arrangement of the third magnetic layer (23) makes it possible to suppress noise generated in the circuit in a configuration different from the conventional one.
[0140] In the seventh embodiment of the common-mode noise filter (1; 1A; 1F), when the laminated portion (26) is viewed from the side, at least a portion of the second coil conductor (4; 4A) and at least a portion of the third coil conductor (5; 5A) overlap with the third magnetic layer (23).
[0141] According to this embodiment, the arrangement of the four coil conductors and the arrangement of the third magnetic layer (23) makes it possible to suppress noise generated in the circuit in a configuration different from the conventional one.
[0142] In the eighth embodiment of the common-mode noise filter (1B), when the laminated portion (26) is viewed from the side, at least a portion of the second coil conductor (4B) or at least a portion of the third coil conductor (5B) overlaps with the third magnetic layer (23) in any of the first to second and sixth embodiments.
[0143] According to this embodiment, the arrangement of the four coil conductors and the arrangement of the third magnetic layer (23) makes it possible to suppress noise generated in the circuit in a configuration different from the conventional one.
[0144] The common-mode noise filter (1F) of the ninth embodiment further comprises a magnetic axis (8) in the laminated portion (26) of any of the first to eighth embodiments. The magnetic axis (8) is formed on a central axis connecting the first magnetic layer (21) and the second magnetic layer (25).
[0145] According to this embodiment, the laminated portion (26) further has a magnetic axis (8), which makes it possible to suppress noise generated in the circuit in a configuration different from the conventional one.
[0146] This common-mode noise filter can suppress noise generated in circuits with a configuration different from conventional ones. Thus, this common-mode noise filter is industrially useful.
[0147] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G Common mode noise filter 2a, 2c First coil 2b, 2d Second coil 3, 3A, 3B, 3C, 3D, 3E, 91 First coil conductor 4, 4A, 4B, 4C, 4D, 4E, 92 Second coil conductor 5, 5A, 5B, 5C, 5D, 5E, 93 Third coil conductor 6, 6A, 6B, 6C, 6D, 6E, 94 Fourth coil conductor 8 Magnetic axis 21 First magnetic layer 22 First non-magnetic layer 22a, 22x First layer 22b, 22y Second layer 23 Third magnetic layer 24 Second non-magnetic layer 22z, 24a Third layer 24b, 24x Fourth layer 25 Second magnetic layer 26 Laminated section 95 Fifth coil conductor 96 Sixth coil conductor
Claims
1. A common-mode noise filter comprising: a first magnetic layer and a second magnetic layer arranged in opposing directions toward each other; and a laminated portion arranged to fill the space between the first magnetic layer and the second magnetic layer, wherein the laminated portion has, in order from the first magnetic layer in the opposing direction, a first non-magnetic layer, a third magnetic layer, and a second non-magnetic layer, each further having four or more even-numbered coil conductors that are spirally wound around a central axis along the opposing direction and face each other in the opposing direction, each of the four or more even-numbered coil conductors is electrically connected to each other in different combinations to form two or more coils, the first coil of the two or more coils is formed to sandwich at least one coil conductor from two or more coil conductors included in the second coil of the two or more coils in the opposing direction, and the third magnetic layer is arranged such that the number of coil conductors arranged between the first magnetic layer and the third magnetic layer is the same as the number of coil conductors arranged between the second magnetic layer and the third magnetic layer.
2. The common-mode noise filter according to claim 1, wherein the four or more even-numbered coil conductors are four coil conductors, in order of proximity to the first magnetic layer in the opposing direction, comprising a first coil conductor, a second coil conductor, a third coil conductor, and a fourth coil conductor.
3. The common-mode noise filter according to claim 2, wherein the first coil conductor is arranged in contact with the first magnetic layer, the fourth coil conductor is arranged in contact with the second magnetic layer, and the second coil conductor and the third coil conductor are arranged to sandwich the third magnetic layer.
4. The common-mode noise filter according to claim 3, wherein, when the laminated portion is viewed from the side, at least a portion of the second coil conductor and at least a portion of the third coil conductor overlap with the third magnetic layer.
5. The common-mode noise filter according to claim 3, wherein, when the laminated portion is viewed from the side, at least a portion of the second coil conductor or at least a portion of the third coil conductor overlaps with the third magnetic layer.
6. The common-mode noise filter according to claim 2, wherein the first non-magnetic layer includes a first layer and a second layer in order of proximity to the first magnetic layer in the opposing direction, the second non-magnetic layer includes a third layer and a fourth layer in order of proximity to the first magnetic layer in the opposing direction, the first layer and the second layer are arranged to sandwich the first coil conductor, the third layer and the fourth layer are arranged to sandwich the fourth coil conductor, and the second coil conductor and the third coil conductor are arranged to sandwich the third magnetic layer.
7. The common-mode noise filter according to claim 6, wherein, when the laminated portion is viewed from the side, at least a portion of the second coil conductor and at least a portion of the third coil conductor overlap with the third magnetic layer.
8. The common-mode noise filter according to claim 6, wherein, when the laminated portion is viewed from the side, at least a portion of the second coil conductor or at least a portion of the third coil conductor overlaps with the third magnetic layer.
9. The common-mode noise filter according to any one of claims 1 to 8, wherein the laminated portion further has a magnetic axis, and the magnetic axis is formed on the central axis so as to connect the first magnetic layer and the second magnetic layer.