Circuit board

Abstract

The present invention provides a circuit board in which conduction between a terminal electrode and a land pattern is less likely to be interrupted even after long-term use. The circuit board comprises: a substrate on which a land electrode is provided; and a coil component mounted on the substrate. The coil component comprises: a core having a winding core part extending in the axial direction and a flange part connected to an end, in the axial direction, of the winding core part and extending at least in a direction intersecting the outer peripheral surface of the winding core part; a coil wound around the outer peripheral surface of the winding core part; and a terminal electrode attached to the flange part. The terminal electrode has an inner surface that faces the flange part, and an outer surface that is the rear surface of the inner surface of the terminal electrode and is joined to the land electrode via a joining material. An end, in the axial direction, of the land electrode on the winding core part side is located closer to the winding core part than is an end, in the axial direction, on the winding core part side of a specific outer surface of the outer surface of the terminal electrode, the specific outer surface facing the land electrode in the intersecting direction.

Description

Circuit board

[0001] The present disclosure relates to a circuit board including a board and a coil component mounted on the board.

[0002] An example of a circuit board including a board and a coil component mounted on the board is disclosed in Patent Document 1. In the circuit board disclosed in Patent Document 1, the coil component includes a core and terminal electrodes attached to the core. The terminal electrodes are connected to land patterns provided on the surface of the board via solder as a bonding material.

[0003] Japanese Patent Application Laid-Open No. 2021-132075

[0004] In the circuit board as described above, cracks may occur in the bonding material such as solder due to factors such as pressure from the outside to the circuit board, stress generated inside the circuit board, and aging of the circuit board. The cracks mainly occur at the boundary between the bonding material and the land pattern. The generated cracks expand while extending over time. Due to the expansion of the cracks, the bonding material may be divided into a portion connected to the terminal electrode and a portion connected to the land pattern. When the bonding material is divided, the conduction between the terminal electrode and the land pattern is interrupted. The period until the conduction between the terminal electrode and the land pattern is interrupted can be the life of the circuit board. It is required to extend this life.

[0005] An object of the present disclosure is to solve the above problems and to provide a circuit board in which interruption of conduction between a terminal electrode and a land pattern is unlikely to occur even after long-term use.

[0006] A circuit board according to one aspect of the present disclosure comprises a substrate having a mounting surface on which land electrodes are provided, and a coil component mounted on the mounting surface of the substrate, wherein the coil component comprises a core having a winding core portion extending in the axial direction and a flange portion connected to the axial end of the winding core portion and extending in a crossing direction at least intersecting the axial direction with respect to the outer circumferential surface of the winding core portion, a coil wound around the outer circumferential surface of the winding core portion, and a terminal electrode attached to the flange portion and electrically connected to the coil, wherein the terminal electrode has an inner surface facing the flange portion and an outer surface which is the back surface of the inner surface of the terminal electrode and is joined to the land electrode via a bonding material, and the axial end of the land electrode on the winding core portion side is located on the winding core portion side of the outer surface of the terminal electrode that faces the land electrode in the crossing direction with respect to the land electrode.

[0007] According to this disclosure, it is possible to provide a circuit board that is less prone to interruption of conductivity between terminal electrodes and land patterns even after long-term use.

[0008] A perspective view showing a circuit board according to the first embodiment of this disclosure. A front view showing a circuit board according to the first embodiment of this disclosure. A cross-sectional view showing the section between III-III in Figure 1. A bottom view of a coil component according to the first embodiment of this disclosure. A right side view of a coil component according to the first embodiment of this disclosure. An enlarged view of the area enclosed by the dashed line in Figure 3. A cross-sectional view showing the section between VII-VII in Figure 2. An enlarged view of a circuit board according to the second embodiment of this disclosure corresponding to Figure 6. An enlarged view of a circuit board according to the third embodiment of this disclosure corresponding to Figure 6. An enlarged view of a circuit board according to the fourth embodiment of this disclosure corresponding to Figure 6. An enlarged view of a circuit board according to the fifth embodiment of this disclosure corresponding to Figure 6. A right side view of a coil component according to the sixth embodiment of this disclosure.

[0009] An example of this disclosure is described below with reference to the accompanying drawings. The following description is essentially illustrative and is not intended to limit this disclosure, its applications, or its uses. The drawings are schematic, and the proportions of dimensions, etc., do not necessarily correspond to reality. In the following description, terms indicating specific directions or positions (e.g., terms including "up," "down," "right," "left," "front," and "back") may be used as needed. In this specification and drawings, the X, Y, and Z directions are defined. The Z direction is the thickness direction of the circuit board, and the X and Y directions are directions that intersect the thickness direction of the circuit board. The X and Y directions intersect each other. In the following embodiments and drawings, the X, Y, and Z directions are orthogonal to each other. The X direction is an example of an axial direction. The Y direction is an example of a width direction. The Z direction is an example of an intersecting direction. The use of the aforementioned terms indicating specific directions or positions is for the purpose of facilitating the understanding of this disclosure with reference to the drawings, and the meaning of those terms does not limit the technical scope of this disclosure.

[0010] <First Embodiment> Figure 1 is a perspective view showing a circuit board according to the first embodiment of the present disclosure. Figure 2 is a front view showing a circuit board according to the first embodiment of the present disclosure. Figure 3 is a cross-sectional view showing the section taken along line III-III in Figure 1. Note that the bonding material 3 is not shown in Figure 2.

[0011] As shown in Figures 1, 2, and 3, the circuit board 1 comprises a substrate 2, a bonding material 3, and a coil component 4.

[0012] <Substrate> As shown in Figure 1, the substrate 2 is in the shape of a plate. The substrate 2 may have a structure consisting of a single insulating layer, or it may have a laminated structure consisting of multiple insulating layers stacked together. If the substrate 2 has a laminated structure, internal electrodes may be provided between each insulating layer.

[0013] As shown in Figure 3, land electrodes 2B (see Figure 7) are provided on at least one of the front and back surfaces of the substrate 2. In the first embodiment, the land electrodes 2B are provided on the mounting surface 2A, which is one of the front and back surfaces of the substrate 2. More specifically, the land electrodes 2B are provided in recesses formed on the mounting surface 2A. Note that land electrodes 2B may be provided on both the front and back surfaces of the substrate 2. The land electrodes 2B are made of a conductive material such as copper.

[0014] <Coil component> As shown in Figures 1, 2, and 3, the coil component 4 is mounted on the mounting surface 2A of the substrate 2.

[0015] As shown in Figures 2 and 3, the coil component 4 comprises a core 10, a coil 20, and terminal electrodes 30.

[0016] The core 10 has a winding core portion 11 extending in the X direction, a flange portion 12 connected to the X-direction end 111 of the winding core portion 11, and a plate-shaped core 13 placed on the flange portion 12.

[0017] In the first embodiment, the winding core 11 is rectangular prism-shaped, but it may be other shapes such as a cylinder. The X-direction end 111 of the winding core 11 to which the flange 12 is connected corresponds to the bottom surface of the rectangular prism. In the first embodiment, the flange 12 is integrally formed with the winding core 11, but the flange 12 may be a separate component from the winding core 11. In the first embodiment, the flange 12 is connected to both X-direction ends 111 of the winding core 11. In other words, the core 10 has two flanges 12.

[0018] Viewed along the X direction, the flange portion 12 protrudes outward relative to the core portion 11. The flange portion 12 extends at least in the Z direction relative to the outer circumferential surface 11A of the core portion 11. The outer circumferential surface 11A of the core portion 11 corresponds to the side surface of a rectangular prism.

[0019] The coil 20 is wound around the outer circumferential surface 11A of the winding core 11.

[0020] The terminal electrode 30 is attached to the flange portion 12. The terminal electrode 30 is electrically connected to the coil 20. As shown in Figure 3, the terminal electrode 30 is bonded to the land electrode 2B of the substrate 2 via the bonding material 3. Thus, the coil 20 and the land electrode 2B are electrically connected via the bonding material 3 and the terminal electrode 30. In other words, the bonding material 3 is used when bonding the coil component 4 to an external member, the substrate 2. Note that the external member is the substrate 2 in the first embodiment, but is not limited to the substrate 2.

[0021] In the first embodiment, the bonding material 3 is solder. However, the bonding material 3 is not limited to solder; for example, it may be a conductive adhesive or the like.

[0022] <Terminal Electrodes> The configuration of the terminal electrodes 30 will be described in detail below. Figure 4 is a bottom view of the coil component according to the first embodiment of this disclosure. Figure 5 is a right side view of the coil component according to the first embodiment of this disclosure.

[0023] As shown in Figures 2, 4, and 5, the terminal electrode 30 has an inner surface 31, an outer surface 32, and a thickness side surface 33. The inner surface 31 faces inward towards the coil component 4 and faces the flange portion 12. As will be described later, a part of the inner surface 31 is in contact with the flange portion 12, and the rest of the inner surface 31 is separated from the flange portion 12. The outer surface 32 is the back surface of the inner surface 31 and faces outward towards the coil component 4. The outer surface 32 is bonded to the land electrode 2B of the substrate 2 via the bonding material 3. The thickness side surface 33 connects the inner surface 31 and the outer surface 32. The thickness side surface 33 is a surface that extends in the thickness direction of the terminal electrode 30. The thickness direction of the terminal electrode 30 is perpendicular to the direction of the inner surface 31.

[0024] The terminal electrode 30 comprises a main body portion 301 and a lateral projection portion 302. As shown in Figure 2, when viewed along the Y direction, the main body portion 301 is plate-shaped and curved. As a result, the main body portion 301 has a portion extending along the Z direction and a portion extending along the Y direction. As shown in Figures 4 and 5, the lateral projection portion 302 protrudes in the Y direction from the portion of the main body portion 301 that extends along the Y direction. Each of the main body portion 301 and the lateral projection portion 302 has the aforementioned inner surface 31, outer surface 32, and thickness side surface 33.

[0025] Figure 6 is an enlarged view of the area enclosed by the dashed line in Figure 3.

[0026] As shown in Figure 6, the main body portion 301 of the terminal electrode 30 has a fixing portion 34 and a mounting portion 35.

[0027] The fixing portion 34 is fixed to the flange portion 12 either directly or indirectly via an adhesive. In the first embodiment, the fixing portion 34 extends along the Z direction in the main body portion 301. Also in the first embodiment, at least a portion of the opposing surface 31A of the inner surface 31 of the fixing portion 34 is in contact with the outer surface 12A of the flange portion 12 that intersects in the X direction. The opposing surface 31A is the surface of the inner surface 31 that is opposite to the outer surface 12A in the X direction. In the first embodiment, the outer surface 12A is the surface of the flange portion 12 that extends in the Y and Z directions. In the first embodiment, the opposing surface 31A is the surface of the inner surface 31 of the terminal electrode 30 that extends in the Y and Z directions. Therefore, the fixing portion 34 is the portion of the main body portion 301 that is in contact with the outer surface 12A. In Figure 5 and Figure 12, which will be described later, the fixing portion 34 is the portion of the terminal electrode 30 enclosed by the dashed line.

[0028] As shown in Figures 5 and 6, the fixing portion 34 has an inner portion 36 and an outer portion 37. The inner portion 36 is attached to the outer surface 12A of the flange portion 12. The outer portion 37 is continuous with the inner portion 36. A part of the outer portion 37 is attached to the outer surface 12A of the flange portion 12.

[0029] As shown in Figure 5, when viewed along the X direction, the inner portion 36 overlaps the winding core portion 11 of the core 10, while the outer portion 37 does not overlap the winding core portion 11 of the core 10. In Figure 5, the inner portion 36 is the part of the fixing portion 34 that overlaps the winding core portion 11, indicated by the dashed line (in other words, the inner portion of the area enclosed by the dashed line). The outer portion 37 is the part of the fixing portion 34 that does not overlap the winding core portion 11 (in other words, the outer portion of the area enclosed by the dashed line). In Figure 6, the boundary 34A between the inner portion 36 and the outer portion 37 of the fixing portion 34 is indicated by a dashed line.

[0030] As shown in Figure 6, the outer portion 37 has a bent portion 37A. The bent portion 37A is located on the side of the outer portion 37 opposite to the boundary 34A with the inner portion 36. The outer portion 37, which extends from the boundary 34A along the Z direction, changes direction of extension at the bent portion 37A from the Z direction to the X direction. In other words, the bent portion 37A is bent from the Z direction along the outer surface 12A of the flange portion 12 to the X direction.

[0031] In the first embodiment, the inner surface 31 of the bent portion 37A is not in contact with the outer surface 12A of the flange portion 12. However, at least a portion of the inner surface 31 of the bent portion 37A may be in contact with the outer surface 12A of the flange portion 12.

[0032] A filling portion 40 is interposed between the inner surface 31 of the terminal electrode 30 and the outer surface 12A of the flange portion 12, with adhesive filling in at least a portion of the space. In the first embodiment, a recess is provided in the inner surface 31 of the terminal electrode 30, and the filling portion 40 is formed by filling the recess with adhesive.

[0033] The mounting portion 35 extends straight along the X direction. However, the direction in which the mounting portion 35 extends is not limited to being perfectly parallel to the X direction; it may also extend along a direction that is slightly inclined with respect to the X direction. In other words, the mounting portion 35 may extend approximately along the X direction.

[0034] The mounting portion 35 faces the end face 12B of the flange portion 12 on the winding core portion 11 side in the Z direction. The end face 12B of the flange portion 12 is the tip surface of the protruding portion of the flange portion 12 that protrudes outward from the winding core portion 11. In other words, the end face 12B of the flange portion 12 is the outer circumferential surface of the flange portion 12 when viewed along the X direction.

[0035] A gap 50 is provided between the end face 12B and the mounting portion 35. In other words, a gap 50 is provided between the end face 12B and the inner surface 31 of the terminal electrode 30. In the first embodiment, the gap 50 extends over the entire area between the end face 12B and the mounting portion 35. The gap 50 has an opening 51 that opens towards the winding core portion 11 in the X direction. That is, the gap 50 opens towards the winding core portion 11 in the X direction. In other words, the gap 50 opens toward the inside of the coil component 4 in the X direction.

[0036] The gap 50 may be provided only in a portion of the space between the end face 12B and the mounting portion 35. However, even in this case, the gap 50 has an opening 51 that opens towards the winding core portion 11 in the X direction. For example, in Figure 6, the inclined surface 12E of the flange portion 12 and the inner surface 31 of the terminal electrode 30 may be in contact. In this case, the gap 50 is not provided in the portion between the inclined surface 12E and the inner surface 31. Also, adhesive may be filled in a portion of the space between the end face 12B and the mounting portion 35.

[0037] The thickness side surface 33 of the terminal electrode 30 has a tip side surface 33A. The tip side surface 33A is a part of the thickness side surface 33 of the mounting portion 35. The tip side surface 33A is the surface of the thickness side surface 33 located at the end of the mounting portion 35 on the winding core portion 11 side in the X direction. The boundary between the tip side surface 33A and the inner surface 31 is the end 31B of the inner surface 31 on the winding core portion 11 side of the mounting portion 35. The boundary between the tip side surface 33A and the outer surface 32 is the end 32A of the outer surface 32 on the winding core portion 11 side of the mounting portion 35. In other words, the tip side surface 33A is the surface that connects the end 32A of the specific outer surface 32B of the terminal electrode 30 on the winding core portion 11 side in the X direction to the inner surface 31 of the terminal electrode 30. The specific outer surface 32B is the surface of the outer surface 32 of the terminal electrode 30 that faces the land electrode 2B in the Z direction. In other words, the mounting portion 35 is the part of the terminal electrode 30 that includes a specific outer surface 32B.

[0038] In the X direction, the end portion 31B of the inner surface 31 is located closer to the winding core portion 11 than the end portion 32A of the outer surface 32.

[0039] As a result, in the first embodiment, the tip side surface 33A is an inclined surface with respect to the Z direction when viewed along the Y direction. However, the tip side surface 33A may have a shape other than the inclined surface, provided that in the X direction, the end 31B is located closer to the winding core 11 than the end 32A. For example, the tip side surface 33A may be a curved surface when viewed along the Y direction. In this case, the tip of the curved surface may be located closer to the winding core 11 than at least one of the end 31B and the end 32A in the X direction.

[0040] In the X direction, the end portion of the mounting portion 35 on the bobbin portion 11 side (in other words, the tip end portion of the mounting portion 35) is located on the bobbin portion 11 side with respect to the end portion of the end face 12B on the bobbin portion 11 side.

[0041] In the first embodiment, in the X direction, the end portion of the mounting portion 35 on the bobbin portion 11 side is the end portion 31B of the inner surface 31 on the bobbin portion 11 side of the mounting portion 35.

[0042] In the first embodiment as well, as will be described in detail below, the end portion of the end face 12B in the X direction is the intersection point 12Ba.

[0043] The flange portion 12 includes a protruding side surface 12C extending from the outer peripheral surface 11A of the bobbin portion 11 to the end face 12B. The boundary portion 12D between the end face 12B and the protruding side surface 12C is chamfered. The type of chamfering is arbitrary. For example, the boundary portion 12D may be chamfered with a C-chamfer instead of an R-chamfer.

[0044] When the boundary portion 12D is chamfered with an R-chamfer as in the first embodiment, it is desirable to define the boundary between the protruding side surface 12C and the end face 12B. Therefore, in the first embodiment, the intersection point 12Ba between the virtual plane including the end face 12B and the virtual plane including the protruding side surface 12C as viewed along the Y direction is defined as the end portion of the end face 12B on the bobbin portion 11 side in the X direction. The intersection point 12Ba can be the end portion of the end face 12B on the bobbin portion 11 side in the X direction when the boundary portion 12D is not chamfered with an R-chamfer.

[0045] Note that the end portion of the end face 12B on the bobbin portion 11 side in the X direction is not limited to the intersection point 12Ba. For example, the central position of the boundary portion 12D in the X direction may be defined as the end portion of the end face 12B on the bobbin portion 11 side in the X direction.

[0046] The size D1 of the gap 50 in the Z direction is equal to or less than the thickness T1 of the terminal electrode 30. The size D1 of the gap 50 is the length of the gap 50 in the Z direction. In the first embodiment, the terminal electrode 30 has a constant thickness in most parts. Therefore, the thickness T1 of the terminal electrode 30 corresponds to the length of the mounting portion 35 in the Z direction.

[0047] Incidentally, in the first embodiment, the size D1 of the gap 50 is the maximum size in the gap 50 (i.e., the size of the opening 51), but it may be, for example, the average size. When the thickness of the mounting portion 35 is not constant, for example, the thickness T1 of the mounting portion 35 may be the maximum thickness of the mounting portion 35 or the average thickness.

[0048] The thickness of the terminal electrode 30 does not have to be constant. For example, as shown by the dashed line in FIG. 6, the thickness T1' of the bent portion 37A may be thinner than the thickness T1 of the portion other than the bent portion 37A in the terminal electrode 30.

[0049] The inner surface 31 of the terminal electrode 30 has a specific inner surface 31C. The specific inner surface 31C is the surface of the inner surface 31 of the terminal electrode 30 that is located in the mounting portion 35. That is, the specific inner surface 31C faces the end face 12B in the Z direction. In the first embodiment, the specific inner surface 31C has a bent portion 31Ca. The bent portion 31Ca is located at a position farther from the core portion 11 than the end portion 31B in the X direction.

[0050] In the Z direction, the distance D2 between the end portion 31B and the end face 12B is larger than the distance D3 between the bent portion 31Ca of the terminal electrode 30 and the end face 12B.

[0051] As a result, in the first embodiment, the portion between the end portion 31B and the end face 12B of the specific inner surface 31C is an inclined surface with respect to the X direction when viewed along the Y direction. Note that the portion may have a shape other than the inclined surface. For example, the portion may be a curved surface that is curved when viewed along the Y direction. In this case, the tip of the curved surface may be located on the end face 12B side rather than the bent portion 31Ca in the Z direction.

[0052] FIG. 7 is a cross-sectional view showing the VII-VII cross-section of FIG. 2.

[0053] As shown in FIGS. 6 and 7, the end portion 2Ba on the core portion 11 side of the land electrode 2B in the X direction is located on the core portion 11 side rather than the end portion 32A on the core portion 11 side of the mounting portion 35 of the outer surface 32.

[0054] The outer edge of the land electrode 2B on the winding core portion 11 side in the X direction is the end portion 2Ba of the land electrode 2B on the winding core portion 11 side in the X direction. Also, the outer edge of the specific outer surface 32B of the terminal electrode 30 on the winding core portion 11 side in the X direction is the end portion 32A. Note that the end portion 32A, together with the end portion 31B of the inner surface 31, is the outer edge of the tip side portion 33A in the Z direction. Therefore, when viewed along the Z direction (in other words, in the Y direction), the end portion 2Ba of the land electrode 2B on the winding core portion 11 side in the X direction is parallel or approximately parallel to the end portion 32A, the end portion 31B, and the tip side portion 33A. In Figure 7, the end portion 2Ba is parallel to the end portion 32A, the end portion 31B, and the tip side portion 33A. Also, although Figure 7 shows the same position for the end portion 32A and the end portion 31B, in the first embodiment, as shown in Figure 6, the positions of the end portion 32A and the end portion 31B in the X direction are different.

[0055] As shown in Figure 7, in the Y direction, which is perpendicular to the X direction and along the mounting surface 2A of the substrate 2, at least one of the two ends 2Bb of the land electrode 2B is located outside the terminal electrode 30. In Figure 7, in the Y direction, both of the two ends 2Bb of the land electrode 2B are located outside the terminal electrode 30. In other words, in Figure 7, in the Y direction, the land electrode 2B is located between the two ends 2Bb.

[0056] <Plating Layer> As shown in Figure 6, the coil component 4 is equipped with a plating layer 38. Note that the plating layer 38 is shown in Figure 6 and Figures 8 to 11 described later, but the plating layer 38 is not shown in figures other than Figure 6 and Figures 8 to 11.

[0057] The plating layer 38 covers at least a portion of the terminal electrode 30. In the first embodiment, the plating layer 38 covers the outer surface 32 of the terminal electrode 30. On the other hand, in the first embodiment, the plating layer 38 does not cover the inner surface 31 and the thickness side surface 33 of the terminal electrode 30. In other words, in the first embodiment, the tip side surface 33A, which is part of the thickness side surface 33, is not covered by the plating layer 38.

[0058] In the first embodiment, the plating layer 38 covers the entire outer surface 32 of the terminal electrode 30, but it may cover only a part of the outer surface 32.

[0059] <Bonding Material> In the first embodiment, the bonding material 3 is solder, as described above. Also in the first embodiment, the terminal electrode 30 is made of a metal plate composed of phosphor bronze. In the first embodiment, the plating layer 38 contains tin or nickel. The wettability of tin to solder is higher than that of phosphor bronze to solder, and the wettability of nickel to solder is higher than that of phosphor bronze to solder. In other words, the wettability of the plating layer 38 to the bonding material 3 is higher than the wettability of the terminal electrode 30 to the bonding material 3.

[0060] As a result, in the first embodiment, when the coil component 4 is mounted on the substrate 2, the bonding material 3 covers the plating layer 38, but does not cover the portion of the terminal electrode 30 that is exposed to the outside (for example, the thickness side surface 33).

[0061] As mentioned above, the bonding material 3 is not limited to solder. Also, the terminal electrode 30 is not limited to phosphor bronze, and the plating layer 38 is not limited to tin or nickel. Furthermore, the portion of the terminal electrode 30 that is exposed to the outside may be made of phosphor bronze, while the portion that is not exposed to the outside may be made of a material other than phosphor bronze. However, regardless of the materials that the bonding material 3, terminal electrode 30, and plating layer 38 are made of, the wettability of the plating layer 38 to the bonding material 3 is higher than the wettability of the terminal electrode 30 to the bonding material 3.

[0062] For example, if the bonding material 3 is a conductive adhesive, the terminal electrode 30 is made of phosphor bronze, and the plating layer 38 contains nickel or gold. In this case as well, the terminal electrode 30 is not limited to phosphor bronze, and the plating layer 38 is not limited to nickel or gold.

[0063] The thickness T2 of the bonding material 3 between the land electrode 2B and the specific outer surface 32B of the terminal electrode 30 is greater than or equal to the size D1 of the gap 50 in the Z direction. In the configuration shown in Figure 6, the thickness T2 of the bonding material 3 is greater than the size D1 of the gap 50.

[0064] Furthermore, the thickness T2 of the bonding material 3 between the land electrode 2B and the specific outer surface 32B of the terminal electrode 30 is more than half the thickness of the terminal electrode 30. In the configuration shown in Figure 6, the thickness T2 of the bonding material 3 is greater than half the thickness T1 of the mounting portion 35 of the terminal electrode 30 and less than the thickness T1.

[0065] As shown in Figure 6, the joining material 3 comprises an inner covering portion 3A and an outer covering portion 3B. The inner covering portion 3A is the part of the joining material 3 that covers the inner portion 36 (see Figure 5) from the opposite side of the flange portion 12. The outer covering portion 3B is the part of the joining material 3 that covers the outer portion 37 (see Figure 5) from the opposite side of the flange portion 12. In Figure 6, the boundary 3D between the inner covering portion 3A and the outer covering portion 3B of the joining material 3 is shown by a dashed line.

[0066] The inner covering portion 3A has a protrusion 3Aa that projects in the X direction relative to the outer covering portion 3B. In the configuration shown in Figure 6, the joining material 3 protrudes in the X direction over the entire Y direction in the portion that is at the same height as the inner covering portion 3A in the Z direction. In other words, in the first embodiment, the joining material 3 has a protrusion that projects in the X direction not only in the inner covering portion 3A, but also in the portion of the outer covering portion 3B that is at the same height as the inner covering portion 3A in the Z direction. Of course, the inner covering portion 3A may have a protrusion 3Aa, while the outer covering portion 3B does not have a protrusion.

[0067] In a configuration with a protrusion 3Aa, the thickness of the bonding material 3 differs between the area with the protrusion 3Aa and the area without the protrusion 3Aa. To change the thickness of the bonding material 3 according to the position as described above, one can, for example, change the area of ​​the terminal electrode 30 (specifically, increase the area of ​​the terminal electrode 30 in the area where the thickness of the bonding material 3 is to be increased). Alternatively, one can, for example, increase the thickness of the plating layer 38 in the area where the thickness of the bonding material 3 is to be increased.

[0068] The joining material 3 has a cavity 3C, which is a sealed space. In the configuration shown in Figure 6, the joining material 3 has three cavities 3C of different sizes. However, the number of cavities 3C in the joining material 3 is not limited to three, and the size of each cavity 3C is not limited to the size shown in Figure 6. For example, at least two of the multiple cavities 3C in the joining material 3 may be the same size.

[0069] <Effects> The circuit board 1 and coil component 4 according to the first embodiment can exhibit the following effects.

[0070] According to the first embodiment, the mounting portion 35 extends straight. This simplifies the configuration of the terminal electrode 30 compared to a configuration in which the mounting portion 35 is curved. Furthermore, in the case of a configuration in which the mounting portion 35 is curved, there is a risk that the mounting portion 35 may bend further in an unintended direction starting from the curved part. However, in the first embodiment, since the mounting portion 35 extends straight, the possibility of the mounting portion 35 bending in an unintended direction can be reduced.

[0071] According to the first embodiment, the size D1 of the gap 50 in the Z direction is less than or equal to the thickness T1 of the mounting portion 35. Therefore, compared to a configuration in which the size D1 of the gap 50 is larger than the thickness T1 of the mounting portion 35, the coil component 4 can be made smaller in the Z direction. In addition, compared to the said configuration, the bending of the mounting portion 35 in the Z direction can be reduced.

[0072] However, if the gap 50 is narrow, there is a higher possibility that the bonding material 3 will fill the gap 50 when the coil component 4 is joined to an external member such as the substrate 2 by the bonding material 3. If the bonding material 3 fills the gap 50, the range of motion between the flange portion 12 and the terminal electrode 30 will be narrowed, and at least one of the flange portion 12, bonding material 3, and terminal electrode 30 may suffer significant damage due to thermal shock from the substrate 2, etc. In contrast, according to the first embodiment, in the X direction, the end portion 31B of the mounting portion 35 on the winding core portion 11 side is located closer to the winding core portion 11 than the intersection point 12Ba, which is the end portion of the end face 12B of the flange portion 12 on the winding core portion 11 side. This makes it possible to lengthen the path from a specific outer surface 32B of the mounting portion 35 through the tip side surface 33A of the mounting portion 35 to reach the gap 50. As a result, when the coil component 4 is joined to an external member such as the substrate 2 by the bonding material 3, it is possible to reduce the amount of bonding material 3 that enters the gap 50 by traveling along the side surface of the mounting portion 35 from the outer surface of the mounting portion 35.

[0073] According to the first embodiment, in the X direction, the end portion 31B of the inner surface 31 of the terminal electrode 30 on the winding core portion 11 side of the mounting portion 35 is located closer to the winding core portion 11 than the end portion 32A of the outer surface 32 of the terminal electrode 30 on the winding core portion 11 side of the mounting portion 35. As a result, the bonding material 3 is less likely to reach the gap 50 along the front side surface 33A of the mounting portion 35. Consequently, it is possible to reduce the amount of bonding material 3 that enters the gap 50 from a specific outer surface 32B of the mounting portion 35 along the front side surface 33A of the mounting portion 35.

[0074] According to the first embodiment, the boundary portion 12D between the end face 12B and the protruding side surface 12C is chamfered, which increases the distance between the terminal electrode 30 and the core 10 near the opening 51 of the gap 50. This reduces the possibility of the joining material 3 coming into contact with the core 10 near the opening 51 of the gap 50.

[0075] According to the first embodiment, in the Z direction, the distance D2 between the end portion 31B and the end face 12B is greater than the distance D3 between the bent portion 31Ca of the terminal electrode 30 and the end face 12B. Because the distance D2 is large, the possibility of the joining material 3 coming into contact with the core 10 when it reaches the vicinity of the opening 51 of the gap 50 can be reduced.

[0076] According to the first embodiment, the bent portion 31Ca is located higher than the end portion 31B. Therefore, when the joining material 3 reaches the vicinity of the opening 51 of the gap 50, the possibility of the joining material 3 penetrating further into the gap 50 can be reduced.

[0077] According to the first embodiment, the tip side surface 33A of the terminal electrode 30 is not covered by the plating layer 38. That is, the tip side surface 33A of the terminal electrode 30 exposes the components that make up the terminal electrode 30. Therefore, when the coil component 4 is joined to an external component such as the substrate 2 by the bonding material 3, it is possible to reduce the amount of bonding material 3 that gets wet from the outer surface 32 of the terminal electrode 30 up to the tip side surface 33A of the terminal electrode 30.

[0078] The wettability of tin and nickel to solder is higher than that of phosphor bronze to solder. According to the first embodiment, the bonding material 3 is solder, the portion of the terminal electrode 30 exposed to the outside is made of phosphor bronze, and the plating layer 38 contains tin or nickel. Therefore, the wettability of the plating layer 38 to the bonding material 3 can be made higher than the wettability of the terminal electrode 30 to the bonding material 3. This makes it possible to clearly separate the portion of the terminal electrode 30 to which solder easily adheres from the portion to which solder does not easily adhere.

[0079] According to the first embodiment, the gap 50 is provided over the entire area between the end face 12B and the mounting portion 35. Therefore, it is possible to suppress the effect of pressure from one end face 12B and the mounting portion 35 to the other due to thermal deformation of the end face 12B and the mounting portion 35.

[0080] In the circuit board disclosed in Patent Document 1, the axial end of the land electrode on the winding core side is in the same position as the axial end of the terminal electrode on the winding core side. Therefore, in the circuit board disclosed in Patent Document 1, when a coil component is joined to a land electrode provided on the substrate with solder as a bonding material, the solder does not spread axially towards the winding core side beyond the portion of the land electrode facing the terminal electrode.

[0081] In contrast, according to the first embodiment, the end portion 2Ba of the land electrode 2B on the winding core portion 11 side in the X direction is located closer to the winding core portion 11 than the end portion 32A of the specific outer surface 32B of the terminal electrode 30 on the winding core portion 11 side in the X direction. Therefore, when the coil component 4 is joined to the land electrode 2B by the joining material 3, the joining material 3 spreads not only over the portion of the land electrode 2B facing the specific outer surface 32B, but also over the portion of the land electrode 2B that does not face the specific outer surface 32B. In other words, in the first embodiment, the joining material 3 that joins the terminal electrode 30 and the land electrode 2B can be spread over a wider area than the circuit board disclosed in Patent Document 1. As a result, if a crack occurs in the joining material 3, the distance from the crack occurrence location to the outer edge of the joining material 3 can be increased, and the period until the crack reaches the outer edge can be increased. As a result, the period until the joining material 3 is separated into the portion connected to the terminal electrode 30 and the portion connected to the land electrode 2B can be increased. In other words, the period until the electrical connection between the terminal electrode 30 and the land electrode 2B is interrupted can be extended.

[0082] According to the first embodiment, the thickness T2 of the bonding material 3 between the land electrode 2B and the specific outer surface 32B of the terminal electrode 30 is greater than or equal to the size D1 of the gap 50 in the Z direction. Therefore, the amount of bonding material 3 between the land electrode 2B and the specific outer surface 32B can be increased compared to a configuration in which the thickness T2 of the bonding material 3 is less than the size D1 of the gap 50. As a result, when at least one of the bonding material 3, the terminal electrode 30, and the substrate 2 deforms due to thermal load or the like, the stress generated in the bonding material 3 due to the deformation is distributed. As a result, the maximum stress is reduced, and the occurrence of cracks in the bonding material 3 can be suppressed.

[0083] According to the first embodiment, the thickness T2 of the bonding material between the land electrode 2B and the specific outer surface 32B of the terminal electrode 30 is half or more of the thickness T1 of the terminal electrode 30. Therefore, the amount of bonding material between the land electrode 2B and the specific outer surface 32B can be increased compared to a configuration in which the thickness T2 of the bonding material 3 is less than half of the thickness T1 of the terminal electrode 30. As a result, when at least one of the bonding material 3, the terminal electrode 30, and the substrate 2 deforms due to thermal load or the like, the stress generated in the bonding material 3 due to the deformation is distributed. As a result, the maximum stress is reduced, and the occurrence of cracks in the bonding material 3 can be suppressed.

[0084] According to the first embodiment, when viewed along the Z direction, the outer edge of the land electrode 2B on the winding core portion 11 side in the X direction is parallel or substantially parallel to the outer edge of the specific outer surface 32B of the terminal electrode 30 on the winding core portion 11 side in the X direction. Therefore, when the coil component 4 is joined to the land electrode 2B by the joining material 3, the joining material 3 located near the outer edge of the land electrode 2B on the winding core portion 11 side in the X direction is uniformly wetted in the direction in which both outer edges extend toward the outer edge of the specific outer surface 32B of the terminal electrode 30 on the winding core portion 11 side in the X direction. As a result, the stress generated in the joining material 3 is distributed. Consequently, the occurrence of cracks in the joining material 3 can be suppressed.

[0085] According to the first embodiment, the Y-direction end 2Bb of the land electrode 2B is located further out in the Y-direction than the Y-direction end of the outer surface 32 of the terminal electrode 30. Therefore, when the coil component 4 is joined to the land electrode 2B by the joining material 3, the joining material 3 spreads not only over the portion of the land electrode 2B facing the outer surface 32, but also over the portion of the land electrode 2B located further out in the Y-direction than the terminal electrode 30. In other words, in the first embodiment, the joining material 3 that joins the terminal electrode 30 and the land electrode 2B can be spread over a wide area in the Y-direction.

[0086] According to the first embodiment, the inner covering portion 3A is provided with a protrusion 3Aa that projects in the X direction relative to the outer covering portion 3B. This makes it possible to make the combined thickness of the inner portion 36 and the inner covering portion 3A (in other words, the length in the X direction) thicker than the combined thickness of the outer portion 37 and the outer covering portion 3B in the X direction. Therefore, when leakage flux, which is part of the magnetic flux generated when current flows through the coil 20, passes through the inner portion 36 and the inner covering portion 3A along the X direction, the path of the leakage flux in the inner portion 36 and the inner covering portion 3A can be lengthened. This allows more of the high-frequency noise caused by the leakage flux to be consumed as eddy current loss. As a result, high-frequency noise can be reduced. Therefore, the influence of high-frequency noise on other electronic components located near the coil component 4 can be suppressed.

[0087] According to the first embodiment, when the thickness T1' of the bent portion 37A is thin, the terminal electrode 30 is easily bent.

[0088] According to the first embodiment, since the thickness side surface 33 of the terminal electrode 30 is not covered with the plating layer 38, when the coil component 4 is joined to the substrate 2 by the bonding material 3, the bonding material 3 does not easily spread to the thickness side surface 33 of the terminal electrode 30. As a result, most of the bonding material 3 adheres to the outer surface 32 of the terminal electrode 30 rather than the thickness side surface 33 of the terminal electrode 30. In the first embodiment, when the coil component 4 is joined to the substrate 2 with a predetermined amount of bonding material 3, the amount of bonding material 3 adhering to the outer surface 32 of the terminal electrode 30 can be increased compared to a configuration in which the thickness side surface 33 of the terminal electrode 30 is covered with the plating layer 38. As a result, the inner covering portion 3A can be made thicker in the X direction, so the path of leakage flux in the inner covering portion 3A can be lengthened, and more high-frequency noise caused by leakage flux can be consumed as eddy current loss.

[0089] According to the first embodiment, when the joint member 3 deforms due to the action of external forces or internal stresses, the deformation of the joint member 3 can be mitigated by the cavity 3C.

[0090] According to the first embodiment, the presence of a filling portion 40 between the terminal electrode 30 and the outer surface 32 of the flange portion 12 strengthens the adhesive force between the terminal electrode 30 and the core 10.

[0091] <Second Embodiment> Figure 8 is an enlarged view corresponding to Figure 6 of the circuit board according to the second embodiment of this disclosure. The differences from the first embodiment will be explained below. In the second embodiment and each embodiment described later, common parts with the circuit board 1 according to the first embodiment are denoted by the same reference numerals, and their explanations are generally omitted, and will be explained as necessary.

[0092] In the coil component 4 of the circuit board according to the first embodiment, as shown in Figure 6, the plating layer 38 does not cover the thickness side surface 33 of the terminal electrode 30. However, the plating layer 38 may cover at least a portion of the thickness side surface 33 of the terminal electrode 30.

[0093] In the coil component 4A of the circuit board according to the second embodiment, as shown in Figure 8, a portion of the thickness side surface 33 is covered by the plating layer 38, while the portion of the thickness side surface 33 other than that portion is not covered by the plating layer 38.

[0094] For example, the tip side surface 33A of the thickness side surface 33 is not covered by the plating layer 38 in the thickness direction of the terminal electrode 30, on the side of the inner surface 31 of the terminal electrode 30 relative to the central position 33B (more specifically, on the side of the specific inner surface 31C). The thickness direction of the terminal electrode 30 is perpendicular to the inner surface 31, as described above. For example, the thickness direction of the mounting portion 35 of the terminal electrode 30 is the Z direction. The central position 33B is the center of the tip side surface 33A in the Z direction. In other words, the central position 33B is an intermediate position between the end 31B and the end 32A in the Z direction.

[0095] On the other hand, the tip side surface 33A is covered by the plating layer 38 in the thickness direction of the terminal electrode 30, specifically the portion on the outer surface 32 side of the terminal electrode 30 relative to the central position 33B (more specifically, the portion on the specific outer surface 32B side). The portion of the tip side surface 33A covered by the plating layer 38 is continuous with the plating layer 38 covering the outer surface 32. In other words, the bonding material 3 is in contact with the terminal electrode 30 from the specific outer surface 32B to the tip side surface 33A of the terminal electrode 30. That is, the tip side surface 33A is covered by the plating layer 38 in the portion including the end portion 32A, which is the boundary with the outer surface 32.

[0096] Furthermore, the sides of the thickness side surface 33 other than the tip side surface 33A may also be partially covered by the plating layer 38, similar to the tip side surface 33A, while the rest may not be covered by the plating layer 38.

[0097] For example, in Figure 8, an example of a side surface other than the tip side surface 33A of the thickness side surface 33 is the side surface of the upper end of the terminal electrode 30 in the Z direction (in other words, the end of the terminal electrode 30 on the plate-shaped core 13 side in the Z direction). In Figure 8, in the thickness direction of the terminal electrode 30, the portion of this side surface that is on the inner surface 31 side of the terminal electrode 30 with respect to the central position 33C (more specifically, the portion on the opposing surface 31A side) is not covered by the plating layer 38. The thickness direction of the terminal electrode 30 in this side surface is the X direction. On the other hand, in the thickness direction of the terminal electrode 30, the portion of this side surface that is on the outer surface 32 side of the terminal electrode 30 with respect to the central position 33B is covered by the plating layer 38. Furthermore, the portion of this side surface that is covered by the plating layer 38 is continuous with the plating layer 38 that covers the outer surface 32.

[0098] Furthermore, of the sides of the thickness side surface 33 other than the tip side surface 33A, only a portion of these sides may be covered by the plating layer 38. In this case, the sides other than the portion covered by the plating layer 38 are not covered by the plating layer 38. For example, on the thickness side surface 33 of the main body portion 301 of the terminal electrode 30, a portion of it may be covered by the plating layer 38, while the thickness side surface 33 of the lateral projection portion 302 of the terminal electrode 30 may not be covered by the plating layer 38.

[0099] In the configuration shown in Figure 8, the boundary between the portion of the thickness side surface 33 covered by the plating layer 38 and the portion that is not covered is at the central positions 33B and 33C. However, this boundary is not limited to the central positions 33B and 33C. For example, the boundary may be located closer to the outer surface 32 than the central positions 33B and 33C. One example of this is a configuration in which the plating layer 38 covers only the area of ​​the thickness side surface 33 near the boundary with the outer surface 32. In a configuration where the boundary is located closer to the outer surface 32 than the central positions 33B and 33C, the proportion of the thickness side surface 33 that is not covered by the plating layer 38 is larger than in the configuration shown in Figure 8.

[0100] The thickness T3 of the plating layer 38 covering the side surface 33 of the terminal electrode 30 is thinner than the thickness T4 of the plating layer 38 covering the outer surface 32 of the terminal electrode 30. In the second embodiment, thicknesses T3 and T4 are average thicknesses.

[0101] In the second embodiment, the following effects are achieved.

[0102] According to the second embodiment, the wettability of the plating layer 38 to the bonding material 3 is higher than the wettability of the terminal electrode 30 to the bonding material 3. In other words, it is more difficult for the bonding material 3 to spread along the surface of the terminal electrode 30 than it is for the bonding material 3 to spread along the surface of the plating layer 38.

[0103] In the second embodiment, the tip side surface 33A of the terminal electrode 30 is not covered by the plating layer 38 in the thickness direction, on the side of the inner surface 31 of the terminal electrode 30 relative to the central position 33B. Therefore, in the second embodiment, it is possible to reduce the spread of the bonding material 3 on the tip side surface 33A toward the inner surface 31 beyond the central position 33B. This reduces the amount of bonding material 3 that travels from the outer surface 32 along the tip side surface 33A into the gap 50 between the core 10 and the inner surface 31. As a result, the gap 50 is less likely to be filled with bonding material 3, and the pressure acting from one of the core 10 and the terminal electrode 30 to the other via the bonding material 3 is reduced. Consequently, damage caused by the influence from one of the core 10 and the terminal electrode 30 to the other can be reduced.

[0104] According to the second embodiment, at least a portion of the outer surface 32 of the terminal electrode 30 is covered with a plating layer 38 that has high wettability with respect to the bonding material 3. Therefore, the adhesion between the terminal electrode 30 and the bonding material 3 can be improved.

[0105] According to the second embodiment, when the bonding material 3 spreads from the outer surface 32 onto the thickness side surface 33 of the terminal electrode 30, it is possible to reduce the amount of bonding material 3 on the outer surface 32 that travels from the outer surface 32 along the thickness side surface 33 and enters the space between the core 10 and the inner surface 31 of the terminal electrode 30. In other words, according to the second embodiment, it is possible to reduce the amount of bonding material 3 that enters the space between the core 10 and the inner surface 31 even in parts of the thickness side surface 33 other than the tip side surface 33A.

[0106] According to the second embodiment, when the coil component 4 is joined to an external member such as the substrate 2 by the bonding material 3, the bonding material 3 on the outer surface 32 tends to spread to the portion covered by the plating layer 38 on the thickness side surface 33. As a result, the terminal electrode 30 is covered by the bonding material 3 not only on the outer surface 32 but also on a portion of the thickness side surface 33. Therefore, the adhesion between the terminal electrode 30 and the bonding material 3 can be increased. As a result, the stress generated inside the bonding material 3 due to thermal deformation of the bonding material 3 is dispersed. In addition, the pressure acting on the bonding material 3 from the outside, such as the core 10 and the terminal electrode 30, is dispersed. This makes it possible to suppress the occurrence of cracks in the bonding material 3.

[0107] According to the second embodiment, the thickness T3 of the plating layer 38 covering the thickness side surface 33 of the terminal electrode 30 is thinner than the thickness T4 of the plating layer 38 covering the outer surface 32 of the terminal electrode 30. Therefore, it is possible to reduce the spread of the bonding material 3 on the outer surface 32 of the terminal electrode 30 onto the thickness side surface 33. Furthermore, the thickness of the bonding material 3 on the outer surface 32 of the terminal electrode 30 can be made thicker than the thickness of the bonding material 3 on the thickness side surface 33 of the terminal electrode 30.

[0108] According to the second embodiment, the terminal electrode 30 is covered by the bonding material 3 not only on the specific outer surface 32B but also on the tip side surface 33A. This increases the attractive force in the X direction between the terminal electrode 30 and the bonding material 3. As a result, the resistance of the terminal electrode 30 and the bonding material 3 to stress in the Y direction intersecting the X and Z directions increases. Furthermore, according to the second embodiment, the bonding material 3 covering the tip side surface 33A functions as a wall against vibrations of the terminal electrode 30 in the X direction. This makes the terminal electrode 30 and the bonding material 3 stronger against vibrations in the X direction. Therefore, according to the second embodiment, the terminal electrode 30 and the bonding material 3 can be made stronger against vibrations in the X and Y directions. As a result, the occurrence of cracks in the bonding material 3 can be suppressed.

[0109] <Third Embodiment> Figure 9 is an enlarged view corresponding to Figure 6 of the circuit board according to the third embodiment of this disclosure. The differences from the first embodiment will be explained below.

[0110] In the coil component 4 of the circuit board according to the first embodiment, as shown in Figure 6, the filling portion 40 is provided in a position that overlaps both the inner portion 36 and the outer portion 37 when viewed along the X direction. However, as shown in Figure 9, when viewed along the X direction, the filling portion 40 may not be provided in a position that overlaps the inner portion 36, but only in a position that overlaps the outer portion 37. In such a coil component 4B of the circuit board according to the third embodiment, the entire surface of the portion of the inner surface 31 of the terminal electrode 30 corresponding to the inner portion 36 is in contact with the outer surface 12A of the flange portion 12.

[0111] In the third embodiment, the following effects are achieved.

[0112] According to the third embodiment, when viewed along the X direction, the filling portion 40 is not provided in the portion that overlaps with the winding core portion 11. The amount of the inner portion 36 can be increased by the amount by which the filling portion 40 is not provided. As a result, when the leakage flux passes through the inner portion 36 and the inner covering portion 3A, the path of the leakage flux in the inner portion 36 and the inner covering portion 3A can be lengthened. As a result, more of the high-frequency noise caused by the leakage flux can be consumed as eddy current loss.

[0113] On the other hand, according to the third embodiment, when viewed along the X direction, the filling portion 40 is provided in a portion that does not overlap with the winding core portion 11. This makes it possible to strengthen the adhesive force between the terminal electrode 30 and the core 10.

[0114] <Fourth Embodiment> Figure 10 is an enlarged view corresponding to Figure 6 of the circuit board according to the fourth embodiment of this disclosure. The differences from the first embodiment will be explained below.

[0115] In the first embodiment, as shown in Figure 6, the coil component 4 includes a filling portion 40. However, as shown in Figure 10, the coil component 4 does not have to include a filling portion 40. In the coil component 4C of the circuit board according to this fourth embodiment, the entire surface of the opposing surface 31A of the inner surface 31 of the terminal electrode 30 is in contact with the outer surface 12A of the flange portion 12.

[0116] The fourth embodiment can achieve the following effects.

[0117] According to the fourth embodiment, the filling portion 40 is not provided across the entire surface of the opposing surface 31A when viewed along the X direction. The amount of the inner portion 36 can be increased by the amount by which the filling portion 40 is not provided. As a result, when the leakage flux passes through the inner portion 36 and the inner covering portion 3A, the path of the leakage flux in the inner portion 36 and the inner covering portion 3A can be lengthened. Consequently, more of the high-frequency noise caused by the leakage flux can be consumed as eddy current loss.

[0118] <Fifth Embodiment> Figure 11 is an enlarged view corresponding to Figure 6 of the circuit board according to the fifth embodiment of this disclosure. The differences from the first embodiment will be explained below.

[0119] In the first embodiment, the terminal electrode 30 has a constant thickness. However, the thickness of the terminal electrode 30 does not have to be constant. The thickness of the terminal electrode 30 is the length of the terminal electrode 30 in the thickness direction. For example, as shown in Figure 11, the thickness of the inner portion 36 and the thickness of the outer portion 37 of the fixing portion 34 of the terminal electrode 30 may be different. In the coil component 4D of the circuit board according to the fifth embodiment shown in Figure 11, the inner portion 36 has a protrusion 36A that projects in the X direction relative to the outer portion 37. As a result, the thickness T5 of the inner portion 36 is greater than the thickness T1 of the portion of the terminal electrode 30 other than the inner portion 36.

[0120] In the configuration shown in Figure 11, the outer edge of the protrusion 36A is located on the outer portion 37. Therefore, the entire inner portion 36 constitutes a part of the protrusion 36A. Of course, the outer edge of the protrusion 36A may also be located on the inner portion 36. In this case, a part of the inner portion 36 constitutes the protrusion 36A.

[0121] The circuit board 1 and coil component 4 according to the fifth embodiment can exhibit the following effects.

[0122] According to the fifth embodiment, the inner portion 36 is provided with a protrusion 36A that projects in the X direction relative to the outer portion 37. This makes the inner portion 36 thicker in the X direction than the outer portion 37. Therefore, when leakage flux, which is part of the magnetic flux generated when current flows through the coil 20, passes through the inner portion 36, the path of the leakage flux in the inner portion 36 can be lengthened. This allows more of the high-frequency noise caused by the leakage flux to be consumed as eddy current loss. As a result, high-frequency noise can be reduced. Therefore, the influence of high-frequency noise on other electronic components located near the coil component 4 can be suppressed.

[0123] <Sixth Embodiment> Figure 12 is a right side view of a coil component according to the sixth embodiment of the present disclosure. The differences from the first embodiment will be explained below.

[0124] In the first embodiment, as shown in Figure 5, the area of ​​the inner portion 36 is smaller than the area of ​​the outer portion 37 when viewed along the X direction. However, as shown in the coil component 4E of the circuit board according to the sixth embodiment in Figure 12, the area of ​​the inner portion 36 may be larger than the area of ​​the outer portion 37 when viewed along the X direction. Also, the area of ​​the inner portion 36 may be the same as the area of ​​the outer portion 37 when viewed along the X direction. In other words, the area of ​​the inner portion 36 may be greater than or equal to the area of ​​the outer portion 37 when viewed along the X direction.

[0125] The circuit board 1 and coil component 4 according to the sixth embodiment can exhibit the following effects.

[0126] According to the sixth embodiment, the leakage flux passing through the inner portion 36 can be increased, so that more of the high-frequency noise caused by the leakage flux can be consumed as eddy current loss.

[0127] The circuit board and coil components described above can also be expressed as follows.

[0128] (A1) A coil component according to a first aspect of the present disclosure comprises: a core having a winding core portion extending in the axial direction and a flange portion connected to the axial end of the winding core portion and projecting in an intersecting direction intersecting the axial direction with respect to the outer circumferential surface of the winding core portion; a coil wound around the outer circumferential surface of the winding core portion; and a terminal electrode made of a metal plate attached to the flange portion and electrically connected to the coil, wherein the terminal electrode has a mounting portion that faces the end face of the flange portion in the intersecting direction and extends straight along the axial direction, a gap is provided in at least a part between the end face and the mounting portion, the gap opens towards the winding core portion in the axial direction, the end of the mounting portion on the winding core portion side is located closer to the winding core portion than the end of the end face on the winding core portion side, and the size of the gap in the intersecting direction is less than or equal to the thickness of the mounting portion.

[0129] (A2) In the coil component of (A1), the terminal electrode may have an inner surface facing the flange and an outer surface which is the back surface of the inner surface of the terminal electrode, and in the axial direction, the end of the inner surface of the terminal electrode that is on the winding core side of the mounting portion may be located closer to the winding core than the end of the outer surface of the terminal electrode that is on the winding core side of the mounting portion.

[0130] (A3) In the coil component of (A1) or (A2), the flange portion may further include a protruding side surface extending from the outer circumferential surface of the winding core portion to the end face, and the boundary between the end face and the protruding side surface may be chamfered.

[0131] (A4) In any one of the coil components from (A1) to (A3), the specific inner surface of the terminal electrode located in the mounting portion may have a bend at a position further from the core than the end on the core side in the axial direction, and in the intersecting direction, the distance between the end on the core side in the axial direction of the specific inner surface of the terminal electrode and the end face may be greater than the distance between the bend of the terminal electrode and the end face.

[0132] (A5) Any one of the coil components from (A1) to (A4) may further include a plating layer covering at least a portion of the terminal electrode, and the wettability of the plating layer to a bonding material used when joining the coil component to an external member may be higher than the wettability of the terminal electrode to the bonding material, and the terminal electrode may have an inner surface facing the flange, an outer surface which is the back surface of the inner surface of the terminal electrode, and a thickness side surface connecting the inner surface of the terminal electrode and the outer surface of the terminal electrode, and the thickness side surface of the terminal electrode may have a tip side surface located at the end of the mounting portion on the winding core side in the axial direction, and the tip side surface of the terminal electrode may not be covered by the plating layer and may be exposed to the outside.

[0133] (A6) In the coil component of (A5), the joining material may be solder, the portion of the terminal electrode exposed to the outside may be made of phosphor bronze, and the plating layer may contain tin or nickel.

[0134] (A7) In any one of the coil components from (A1) to (A6), the gap may be provided over the entire area between the end face and the mounting portion.

[0135] (B1) A coil component according to a second aspect of the present disclosure comprises: a core having a winding core portion extending in the axial direction and a flange portion connected to the axial end of the winding core portion and projecting in an intersecting direction intersecting the axial direction with respect to the outer circumferential surface of the winding core portion; a coil wound around the outer circumferential surface of the winding core portion; a terminal electrode made of a metal plate attached to the flange portion and electrically connected to the coil; and a plating layer covering at least a portion of the terminal electrode, wherein the terminal electrode has a mounting portion facing the intersecting direction with respect to the end face of the flange portion on the winding core portion side in the intersecting direction, a gap is provided in at least a portion between the end face and the mounting portion, the gap opens toward the winding core portion in the axial direction, the wettability of the plating layer to a bonding material used when joining the terminal electrode and the plating layer to an external member is higher than the wettability of the terminal electrode to the bonding material, the terminal electrode has an inner surface facing the flange portion, and an outer surface which is the back surface of the inner surface of the terminal electrode, The terminal electrode has a thickness side surface connecting the inner surface of the terminal electrode and the outer surface of the terminal electrode, the thickness side surface of the terminal electrode has a tip side surface located at the end of the mounting portion on the winding core side in the axial direction, at least a part of the outer surface of the terminal electrode is covered by the plating layer, and the tip side surface of the terminal electrode is not covered by the plating layer in the thickness direction of the terminal electrode, with respect to the central position, and is exposed to the outside.

[0136] (B2) In the coil component of (B1), at least a portion of the thickness side surface of the terminal electrode may not be covered by the plating layer in the thickness direction, with respect to the central position, on the inner surface side of the terminal electrode.

[0137] (B3) In the coil component of (B1) or (B2), at least a portion of the thickness side surface of the terminal electrode may be covered by the plating layer, with respect to the central position in the thickness direction, at least a portion of which is on the outer surface side of the terminal electrode and includes the boundary with the outer surface of the terminal electrode.

[0138] (B4) In the coil component of (B3), the thickness of the plating layer covering the thickness side surface of the terminal electrode may be thinner than the thickness of the plating layer covering the outer surface of the terminal electrode.

[0139] (B5) In any one of the coil components from (B1) to (B4), the joining material may be solder, the portion of the terminal electrode exposed to the outside may be made of phosphor bronze, and the plating layer may contain tin or nickel.

[0140] (C1) A circuit board according to a first aspect of the present disclosure comprises a substrate having a mounting surface on which land electrodes are provided, and a coil component mounted on the mounting surface of the substrate, wherein the coil component comprises a core having a winding core portion extending in the axial direction and a flange portion connected to the axial end of the winding core portion and extending in a crossing direction at least intersecting the axial direction with respect to the outer circumferential surface of the winding core portion, a coil wound around the outer circumferential surface of the winding core portion, and a terminal electrode made of a metal plate attached to the flange portion and electrically connected to the coil, wherein the terminal electrode has an inner surface facing the flange portion and an outer surface which is the back surface of the inner surface of the terminal electrode and is joined to the land electrode via a bonding material, wherein the axial end of the land electrode on the winding core portion side is located on the winding core portion side of the outer surface of the terminal electrode that faces the land electrode in the crossing direction with respect to the land electrode.

[0141] (C2) In the circuit board of (C1), the terminal electrode may have a tip side surface that connects the end on the winding core side in the axial direction on a specific outer surface of the terminal electrode to the inner surface of the terminal electrode, and the bonding material may be in contact with the tip side surface of the terminal electrode from the specific outer surface of the terminal electrode.

[0142] (C3) In the circuit board of (C1) or (C2), a gap may be provided in at least a portion of the flange portion between the end face on the land electrode side and the inner surface of the terminal electrode in the intersecting direction, the gap may open towards the winding core portion in the axial direction, and the thickness of the bonding material between the land electrode and the specific outer surface of the terminal electrode may be greater than or equal to the size of the gap in the intersecting direction.

[0143] (C4) In any one of the circuit boards from (C1) to (C3), the thickness of the bonding material between the land electrode and the specific outer surface of the terminal electrode may be half or more of the thickness of the terminal electrode.

[0144] (C5) In any one of the circuit boards (C1) to (C4), in the width direction perpendicular to the axial direction and along the mounting surface of the board, the outer edge of the land electrode on the winding core side in the axial direction may be parallel or substantially parallel to the outer edge of the specific outer surface of the terminal electrode on the winding core side in the axial direction.

[0145] (C6) In any one of the circuit boards (C1) to (C5), at least one of the ends of the land electrode may be located outside the terminal electrode in the width direction which is perpendicular to the axial direction and along the mounting surface of the board.

[0146] (C7) In any one of the circuit boards from (C1) to (C6), a gap may be provided in at least a portion of the intersecting direction of the flange between the end face on the land electrode side and the inner surface of the terminal electrode, the gap may open towards the winding core in the axial direction, and in the axial direction, the end of the terminal electrode including a specific outer surface on the winding core side may be located closer to the winding core than the end face of the flange on the winding core side.

[0147] (D1) A circuit board according to a second aspect of the present disclosure comprises a substrate and a coil component mounted on the substrate, the coil component comprising: a core having a winding core portion extending in the axial direction and a flange portion connected to the axial end of the winding core portion; a coil wound around the outer circumferential surface of the winding core portion; and a terminal electrode made of a metal plate attached to the flange portion, electrically connected to the coil, and joined to the substrate via a bonding material, the terminal electrode comprising: an inner portion attached to the outer surface of the flange portion intersecting in the axial direction and overlapping the winding core portion when viewed along the axial direction; and an outer portion attached to the outer surface of the flange portion continuous with the inner portion and not overlapping the winding core portion when viewed along the axial direction, the bonding material comprising: an inner covering portion covering the inner portion from the opposite side of the flange portion; and an outer covering portion covering the outer portion from the opposite side of the flange portion, the inner covering portion comprising a convex portion projecting in the axial direction relative to the outer covering portion.

[0148] (D2) In the circuit board of (D1), the outer portion may have a bent portion that is bent from a direction along the outer surface of the flange portion to a direction along the axial direction, and the thickness of the bent portion may be thinner than the thickness of the inner portion.

[0149] (D3) The circuit board of (D1) or (D2) may further include a plating layer that covers a part of the terminal electrode and has a higher wettability to the bonding material than the wettability of the terminal electrode to the bonding material, the terminal electrode may have an inner surface facing the flange, an outer surface which is the back surface of the inner surface of the terminal electrode, and a thickness side surface that connects the inner surface of the terminal electrode and the outer surface of the terminal electrode, the plating layer may cover at least a part of the outer surface of the terminal electrode but may not cover the thickness side surface of the terminal electrode.

[0150] (D4) In any one of the circuit boards (D1) to (D3), the area of ​​the inner portion may be greater than or equal to the area of ​​the outer portion when viewed along the axial direction.

[0151] (D5) In any one of the circuit boards from (D1) to (D4), the bonding material may have a cavity which is a space sealed by the bonding material.

[0152] (D6) In any one of the circuit boards (D1) to (D5), a filling portion may be interposed between the terminal electrode and the outer surface of the flange, in which adhesive is filled.

[0153] (D7) In the circuit board of (D6), the filling portion does not have to be provided in the portion of the inner surface of the terminal electrode that corresponds to the inner portion.

[0154] (D8) In any one of the circuit boards (D1) to (D5), the filling portion, in which adhesive is filled in at least a part of the space between the terminal electrode and the outer surface of the flange, does not have to be provided on the inner surface of the terminal electrode that is opposite to the outer surface of the flange that intersects in the axial direction.

[0155] (D9) A coil component according to a third aspect of the present disclosure comprises: a core having a winding core portion extending in the axial direction and a flange portion connected to the axial end of the winding core portion; a coil wound around the outer circumferential surface of the winding core portion; and a terminal electrode attached to the flange portion and electrically connected to the coil, wherein the terminal electrode comprises: an inner portion attached to the outer surface of the flange portion intersecting in the axial direction and overlapping with the winding core portion when viewed along the axial direction; and an outer portion attached to the outer surface continuously with the inner portion and not overlapping with the winding core portion when viewed along the axial direction, wherein the inner portion comprises a convex portion projecting in the axial direction relative to the outer portion.

[0156] In the coil component of (D10) and (D9), the outer portion may have a bent portion that is bent from a direction along the outer surface of the flange portion to a direction along the axial direction, and the thickness of the bent portion may be thinner than the thickness of the inner portion.

[0157] (D11) The coil component of (D9) or (D10) may further comprise a plating layer that covers a portion of the terminal electrode and has a higher wettability to a bonding material than the wettability of the terminal electrode to the bonding material used when joining the coil component to an external member, the terminal electrode may have an inner surface facing the flange, an outer surface which is the back surface of the inner surface of the terminal electrode, and a thickness side surface connecting the inner surface of the terminal electrode and the outer surface of the terminal electrode, the plating layer may cover at least a portion of the outer surface of the terminal electrode, but may not cover the thickness side surface of the terminal electrode.

[0158] (D12) In any one of the coil components from (D9) to (D11), the area of ​​the inner portion may be greater than or equal to the area of ​​the outer portion when viewed along the axial direction.

[0159] (D13) In any one of the coil components from (D9) to (D12), a filling portion may be interposed between the terminal electrode and the outer surface of the flange, in which adhesive is filled.

[0160] (D14) In the coil component of (D13), the filling portion does not have to be provided in the portion of the inner surface of the terminal electrode that corresponds to the inner portion.

[0161] (D15) In any one of the coil components from (D9) to (D12), the filling portion, in which adhesive is filled in at least a part of the space between the terminal electrode and the outer surface of the flange, does not have to be provided on the inner surface of the terminal electrode that is opposite to the outer surface of the flange.

[0162] Furthermore, by appropriately combining any of the various embodiments described above, the effects of each embodiment can be achieved.

[0163] Although the present invention has been fully described in relation to preferred embodiments with reference to the drawings as appropriate, various modifications and alterations will be obvious to those skilled in the art. Such modifications and alterations should be understood to be included within the scope of the invention as defined in the appended claims, as long as they do not fall outside that scope.

[0164] 1 Circuit board 2 Board (external component) 2A Mounting surface 2B Land electrode 2Ba End 2Bb End 3 Bonding material (solder) 3A Inner covering part 3Aa Protrusion 3B Outer covering part 3C Cavity part 3D Boundary 4 Coil component 10 Core 11 Winding core part 11A Outer surface 111 End 12 Flange part 12A Outer surface 12B End face 12Ba Intersection 12C Protruding side surface 12D Boundary part 12E Inclined surface 13 Plate-shaped core 20 Coil 30 Terminal electrode 301 Main body part 302 Lateral projection part 31 Inner surface 31A Opposing surface 31B End 31C Specific inner surface 31Ca Bent part 32 Outer surface 32A End 32B Specific outer surface 33 Thickness side surface 33A Tip side surface 33B Center position 33C Center position 34 Fixing part 34A Boundary 35 Mounting part 36 Inner part 36A Convex part 37 Outer part 37A Bent part 38 Plating layer 40 Filling part 50 Gap 51 Opening

Claims

1. A circuit board comprising: a substrate having a mounting surface on which land electrodes are provided; and a coil component mounted on the mounting surface of the substrate, wherein the coil component comprises: a core having a winding core portion extending in the axial direction and a flange portion connected to the axial end of the winding core portion and extending in a crossing direction at least intersecting the axial direction with respect to the outer circumferential surface of the winding core portion; a coil wound around the outer circumferential surface of the winding core portion; and a terminal electrode made of a metal plate attached to the flange portion and electrically connected to the coil, wherein the terminal electrode has an inner surface facing the flange portion and an outer surface which is the back surface of the inner surface of the terminal electrode and is joined to the land electrode via a bonding material, and the axial end of the land electrode on the winding core portion side is located closer to the winding core portion than the axial end of the terminal electrode on the winding core portion side of a specific outer surface facing the land electrode in the crossing direction.

2. The circuit board according to claim 1, wherein the terminal electrode has a tip side surface that connects the axial end on the core side of the terminal electrode on a specific outer surface of the terminal electrode to the inner surface of the terminal electrode, and the bonding material is in contact with the tip side surface of the terminal electrode from the specific outer surface of the terminal electrode to the tip side surface of the terminal electrode.

3. The circuit board according to claim 1 or 2, wherein a gap is provided in at least a portion of the flange portion between the end face on the land electrode side and the inner surface of the terminal electrode in the intersecting direction, the gap opens toward the winding core portion in the axial direction, and the thickness of the bonding material between the land electrode and the specific outer surface of the terminal electrode is greater than or equal to the size of the gap in the intersecting direction.

4. The circuit board according to any one of claims 1 to 3, wherein the thickness of the bonding material between the land electrode and the specific outer surface of the terminal electrode is half or more of the thickness of the terminal electrode.

5. The circuit board according to any one of claims 1 to 4, wherein, in the width direction perpendicular to the axial direction and along the mounting surface of the substrate, the outer edge of the land electrode on the winding core side in the axial direction is parallel or substantially parallel to the outer edge of a specific outer surface of the terminal electrode on the winding core side in the axial direction.

6. The circuit board according to any one of claims 1 to 5, wherein at least one of the ends of the land electrode is located outside the terminal electrode in the width direction perpendicular to the axial direction and along the mounting surface of the substrate.

7. The circuit board according to any one of claims 1 to 6, wherein a gap is provided in at least a portion of the flange portion between the end face on the land electrode side and the inner surface of the terminal electrode in the intersecting direction, the gap opens toward the winding core portion in the axial direction, and in the axial direction, the end of the terminal electrode including a specific outer surface toward the winding core portion is located toward the winding core portion than the end face of the flange portion toward the winding core portion.

Images