Passive component

Abstract

A passive component according to one embodiment of the present invention comprises: a body part having a mounting surface, a first surface on the side opposite from the mounting surface, a first side surface and a second side surface serving as a pair of side surfaces opposite from each other, and a third side surface and a fourth side surface serving as another pair of side surfaces opposite from each other; and a pair of external electrodes continuously formed on the mounting surface and at least each of the first side surface and the second side surface among the four side surfaces of the body part. One external electrode among the pair of external electrodes has a projection part. The projection part is formed so as to project toward the other external electrode on the first surface of the body part. The projection part is formed of the same member integrally with the one external electrode.

Description

Passive Components

[0001] The present invention relates to a passive component, and more particularly to a passive component having a polarized coil.

[0002] In passive components having polarity, a marker indicating the polarity is attached to an area that can be seen from the outside, such as a package. Patent Document 1 discloses a coil component having a marking printed thereon. The coil component includes a main body, a coil portion disposed within the main body, first and second external electrodes spaced apart from each other on one surface of the main body and connected to the coil portion, and a marking portion disposed on one surface of the main body and penetrating the second external electrode.

[0003] Patent Document 2 discloses a chip-type coil component with a directional marker. This chip-type coil component includes a magnetic body, a coil pattern embedded in the magnetic body, and a terminal electrode connected to the coil pattern and exposed on the mounting surface of the magnetic body, with a directional marker formed as a recess formed by removing a portion of the magnetic body on the upper surface of the magnetic body opposite the mounting surface.

[0004] JP 2022-180305 A JP 2023-081668 A

[0005] As mentioned above, for passive components such as coil components, markers for identifying polarity and mounting direction are provided on the outside of the package so that they can be recognized visually. However, it is undesirable to require many additional processes to provide the markers. It is also important to ensure that providing the markers on the package does not adversely affect the characteristics of the passive components.

[0006] An object of the present invention is to provide a passive component that can improve characteristics without increasing the number of processes and that has a portion that also functions as a directional marker.

[0007] One aspect of the present invention is a passive component comprising: a main body having a mounting surface, a first surface opposite the mounting surface, a pair of side surfaces facing opposite each other, namely a first side surface and a second side surface, and another pair of side surfaces facing opposite each other, namely a third side surface and a fourth side surface; and a pair of external electrodes formed continuous with at least the first side surface and the second side surface of the four side surfaces of the main body and the mounting surface, wherein one of the pair of external electrodes has a protrusion, the protrusion being formed on the first surface of the main body so as to protrude toward the other external electrode, and the protrusion being formed integrally with the one external electrode from the same material.

[0008] With this configuration, the protrusions function as directional markers for the passive components and also enhance the heat dissipation effect of the heat generated by the passive components. Furthermore, since the protrusions are formed integrally with the external electrodes using the same material, the protrusions can be formed in the same process as the external electrodes.

[0009] In the passive component, it is preferable that one of the external electrodes and the protrusion be integrally formed by electrolytic plating. Furthermore, in the passive component, the main body may contain a magnetic material and further include a coil portion having a polarity and built into the main body. This allows the protrusion to function as a marker indicating the polarity of the coil component, and the heat dissipation effect of the protrusion stabilizes the coil characteristics.

[0010] In the passive component having the coil, it is preferable that the surface of one of the external electrodes that contacts the first surface of the main body is flush with the first surface, thereby suppressing a volume reduction of the magnetic material of the main body due to the provision of the protrusion.

[0011] In the passive component, it is preferable that the area of ​​one of the pair of external electrodes, which has a protrusion, is larger than the area of ​​the other external electrode, which does not have a protrusion, thereby improving the distinguishability of the pair of external electrodes as markers and increasing the total area of ​​the external electrodes to improve the heat dissipation of the passive component.

[0012] In the passive component, the protrusion may be formed so as not to cover a connection portion of the main body between the first surface and the third side surface and a connection portion of the main body between the first surface and the fourth side surface. By forming the protrusion in a portion excluding the connection portions between the first surface and the third side surface and the fourth side surface in this manner, peeling of the protrusion from the main body is less likely to occur.

[0013] In the passive component, it is preferable that one of the external electrodes including the protrusion is formed in a region of the main body where the insulating exterior coating is not present, and that the portion of the protrusion other than the connection portion with the other portion of the external electrode is formed in a curved shape without corners when viewed in a direction perpendicular to the first surface. This makes it easier to form the protrusion when the insulating exterior coating is formed on the main body by screen printing by forming it in a curved shape.

[0014] According to the present invention, it is possible to provide a passive component that can improve characteristics without increasing the number of processes and has a portion that also functions as a directional marker.

[0015] 3A is a perspective view conceptually illustrating the shape of a coil component according to the present embodiment. FIG. 3B is a plan view illustrating the coil component according to the present embodiment. FIG. 3C is an XZ cross-sectional view taken along line AA' in FIG. 2 illustrating the coil component according to the present embodiment. FIG. 3D is an enlarged view of portion A in FIG. 3A. FIG. 3E is a diagram illustrating a simulation result of the temperature distribution of coil component 1A. FIG. 3F is a diagram illustrating a simulation result of the temperature distribution of coil component 1B. FIG. 3G is a diagram illustrating a simulation result of the temperature distribution of coil component 1B. FIG. 3H is a diagram illustrating a simulation result of the temperature distribution of coil component 1C. FIG. 3I is a diagram illustrating a simulation result of the temperature distribution of coil component 1C. FIG. 3I is a diagram illustrating a simulation result of the temperature distribution of coil component 1D. FIG. 3I is a diagram illustrating a simulation result of the temperature distribution of coil component 1D. FIG. 3I is a diagram illustrating a simulation result of the temperature distribution of coil component 2. FIG. 3I is a diagram illustrating a simulation result of the temperature distribution of coil component 2. FIG. 3I is a diagram illustrating a relationship between the area of ​​an external electrode and the temperature of a coil component. 10A and 10B are plan views showing examples of other protrusions.

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components will be denoted by the same reference numerals, and the description of components that have already been described will be omitted as appropriate.

[0017] (Overall Configuration of Coil Component) FIG. 1 is a perspective view conceptually illustrating the shape of a coil component according to this embodiment. FIG. 2 is a plan view illustrating the coil component according to this embodiment. For ease of explanation, in FIGS. 1 and 2 , an exterior coating 50 (described later) is indicated by a two-dot chain line, and some of the internal components of a main body 10 are indicated by a dashed line. The coil component 1 according to this embodiment is an example of a passive component. The coil component 1 includes a main body 10, a pair of external electrodes 21, 22 formed on the main body 10, and a coil portion 30 built into the main body 10. The main body 10 is formed in a substantially rectangular parallelepiped shape and has a mounting surface 11, a surface opposite the mounting surface 11 (first surface 12), and four side surfaces (first side surface 13 a, second side surface 13 b, third side surface 13 c, and fourth side surface 13 d). In this embodiment, the direction perpendicular to the first surface 12 is the Z1-Z2 direction, one of the directions perpendicular to the Z1-Z2 direction is the X1-X2 direction, and the direction perpendicular to the Z1-Z2 direction and the X1-X2 direction is the Y1-Y2 direction. The first side surface 13a and the second side surface 13b of the main body 10 face opposite each other in the X1-X2 direction. Furthermore, the third side surface 13c and the fourth side surface 13d of the main body 10 face opposite each other in the Y1-Y2 direction. A pair of external electrodes 21, 22 are formed on a pair of side surfaces (the first side surface 13a and the second side surface 13b) of the main body 10.

[0018] (Coil portion) The coil portion 30 has a coil conductor portion 31 formed in a spiral shape along the planar direction (X-Y plane) of the first surface 12 of the main body portion 10, for example. The spiral shape, number of turns, size, number of stages, etc. of the coil conductor portion 31 are selected appropriately depending on the specifications of the coil component 1. Furthermore, the conductor (conductive material) constituting the coil conductor portion 31 is not limited as long as it has appropriate conductivity. Specific examples of the conductor constituting the coil conductor portion 31 include metals such as copper, copper alloys, aluminum, and aluminum alloys, and the coil conductor portion 31 can be manufactured using a film formation technique such as plating.

[0019] A lead portion 32 is provided at each end of the coil conductor portion 31. Each lead portion 32 is exposed from the first side surface 13a and the second side surface 13b of the main body portion 10, respectively, and is in conductive contact with the external electrodes 21, 22 at the exposed portions.

[0020] (Main Body) The main body 10 includes a binder and magnetic powder (magnetic material) held in the binder. As described above, the main body 10 is configured in the shape of a substantially rectangular parallelepiped, with a mounting surface 11, a first surface 12, and four side surfaces (first side surface 13a to fourth side surface 13d). The mounting surface 11, the first surface 12, and the four side surfaces (first side surface 13a to fourth side surface 13d) that form the main body 10 are referred to as the surface of the main body 10. A coil conductor 31 is built inside the main body 10.

[0021] The material system of the magnetic powder is not limited. Specific examples of crystalline materials include Fe—Si—Cr alloys, Fe—Ni alloys, Fe—Co alloys, Fe—V alloys, Fe—Al alloys, Fe—Si alloys, Fe—Si—Al alloys, pure iron, and ferrite. Carbonyl iron powder is preferred as pure iron powder. Specific examples of amorphous materials include Fe—Si—B alloys, Fe—P—C alloys, and Co—Fe—Si—B alloys. Specific examples of composite materials include Fe—Zr alloys, Fe—Zr—B alloys, Fe—Si—B—Nb—Cu alloys, and Fe—Si—B—P—Cu alloys. When the magnetic powder is a metal powder containing Fe, the synergistic effect of improving magnetic properties is particularly large.

[0022] The binder contained in the main body 10 binds together particles of magnetic powder and the like contained in the main body 10. This binder is preferably an insulating material in order to impart insulation resistance to the main body 10.

[0023] The material constituting the binder may be an organic material, an inorganic material, or a mixture of an organic material and an inorganic material. The organic material may be a resin material. Examples of the resin material include acrylic resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, and polyester resin. Examples of the inorganic material include glass-based materials such as water glass.

[0024] (External Electrodes) The external electrodes 21, 22 are formed on a pair of side surfaces of the main body 10, the first side surface 13a and the second side surface 13b. The external electrode 21 is formed so as to cover at least the first side surface 13a, and the external electrode 22 is formed so as to cover at least the second side surface 13b. Each of the external electrodes 21, 22 may overlap a portion of the mounting surface 11 or a portion of the first surface 12. The external electrodes 21, 22 are electrically isolated from each other. The material and configuration of the external electrodes 21, 22 are not limited as long as they have appropriate conductivity. One non-limiting example of the external electrodes 21, 22 is a layer having a Cu-plated / Ni-plated / Sn-plated structure from the side closest to the surface of the main body 10.

[0025] (Dummy Conductor Portion) The coil component 1 according to this embodiment may be provided with a dummy conductor portion 33. The dummy conductor portion 33 faces the lead portion 32 in the Z1-Z2 direction and is provided at a distance from the lead portion 32. The dummy conductor portion 33 is not in contact with the external electrodes 21, 22. In Fig. 3B, an insulating layer 34 located between the turns of the coil portion 30 is located between the dummy conductor portion 33 and the external electrode 21, thereby ensuring insulation between the dummy conductor portion 33 and the external electrode 21.

[0026] The presence of the dummy conductor portion 33 reduces the likelihood of pressure variations occurring when applying an external force to place magnetic powder around the coil portion 30, and therefore reduces the likelihood of deformation of the coil portion 30.

[0027] (External Coating) An external coating 50 is provided as an insulating layer on the surface of the main body 10 on which conductive members such as the external electrodes 21 and 22 are not formed. The external coating 50 may include a layer made of resin with an average thickness of 0.10 μm to 15.0 μm. This makes it easy to maintain the magnetic properties of the coil component 1, improve the insulation of the surface of the coil component 1 to increase the reliability of the coil component 1, and improve the appearance of the coil component 1. The coil component 1 does not necessarily have to include the external coating 50. The external coating 50 can be formed at any position on the surface of the main body 10 depending on the purpose.

[0028] (Protrusion) FIG. 3A is an XZ cross-sectional view taken along line A-A' in FIG. 2 illustrating a coil component according to this embodiment. FIG. 3B is an enlarged side view of portion A in FIG. 3A. For ease of explanation, in FIGS. 3A and 3B, the exterior coating 50 is indicated by a two-dot chain line, and some of the internal components of the main body 10 are indicated by dashed lines. In the coil component 1 according to this embodiment, one external electrode 21 of a pair of external electrodes 21, 22 has a protrusion 211. The protrusion 211 is provided on the first surface 12 of the main body 10 (the Z1 side in the Z1-Z2 direction) and is formed so as to protrude from another portion 212 of one external electrode 21 other than the protrusion 211 toward the other external electrode 22. Here, the other portion 212 refers to a portion of one external electrode 21 that is along the first surface 12 and has a constant width that is substantially parallel to the first side surface 13a when viewed in the Z1-Z2 direction. The protrusion 211 is integrally formed with the external electrode 21 from the same material.

[0029] The external electrode 21 having the protrusion 211 and the external electrode 22 are formed by, for example, electrolytic plating. That is, the exterior coating 50 is formed by screen printing or the like on the surface of the main body 10 except for the portions where the external electrodes 21, 22 and the protrusion 211 are to be formed, and then a layer of electrode material is formed by, for example, barrel plating on the surface of the main body 10 that is not covered with the exterior coating 50.

[0030] Since the exterior coating 50 acts as a mask for the plating process, by making the areas where the external electrodes 21 and 22 are formed areas on the surface of the main body 10 where the exterior coating 50 is not formed (uncoated areas), the layer of electrode material formed in the uncoated areas becomes the external electrodes 21 and 22 having protrusions 211.

[0031] In this case, by making the uncoated region of the portion where the external electrode 21 having the protrusion 211 is to be formed continuous, the protrusion 211 and the external electrode 21 are formed integrally from the same material.

[0032] The protrusion 211 is formed on the first surface 12 of the main body 10 so as to protrude from one external electrode 21 toward the other external electrode 22, and therefore can function as a directional marker for the coil component 1. When a coil portion 30 having polarity is built into the main body 10, the protrusion 211 can be used as a polarity marker.

[0033] Here, of the pair of external electrodes 21, 22, it is preferable that the area of ​​one external electrode 21 having the protrusion 211 is larger than the area of ​​the other external electrode 22 not having the protrusion 211. This makes the difference between the pair of external electrodes 21, 22 clear, improving their distinguishability as directional markers for the coil component 1. Furthermore, increasing the total area of ​​the external electrodes can improve the heat dissipation properties of the coil component 1.

[0034] In this way, by providing the protrusions 211, the total area of ​​the external electrodes 21, 22 becomes larger than when the protrusions 211 are not provided. This increases the heat dissipation effect of heat generated from the coil component 1, and improves the characteristics of the coil component 1 (reduced resistance, improved response characteristics, etc.). Furthermore, because the protrusions 211 are formed in the same process as the external electrodes 21, 22, there is no need to add a separate process to form the protrusions 211. Because the protrusions 211 can also be used as markers, there is no need to change the process or increase the number of processes to attach the markers.

[0035] 3B , it is preferable that the surface 21a of one external electrode 21 that contacts the first surface 12 of the main body portion 10 is flush with the first surface 12. This prevents the volume of the main body portion 10 from being reduced when the protruding portion 211 is provided, and makes it possible to prevent a reduction in the volume of the magnetic material of the main body portion 10. Therefore, even if the protruding portion 211 is provided, the characteristics of the coil component 1 will not be deteriorated.

[0036] 2, the protrusion 211 is preferably formed so as not to cover the connection portion (ridge line) 10a between the first surface 12 and the third and fourth side surfaces 13c, 13d of the main body 10. That is, the protrusion 211 is formed so as to extend along the first surface 12 from a position on the external electrode 21 that does not overlap the connection portion 10a of the main body 10 (i.e., on the inner side than the connection portion 10a).

[0037] The protrusion 211 extends from the first side surface 13a of the main body 10 of the external electrode 21 along the first surface 12, and is provided partway along the surface direction of the first surface 12. Since the connection portion 10a of the main body 10 is susceptible to force due to contact with other members during transport of the coil component 1, for example, if the end of the protrusion 211 rests on the connection portion 10a of the main body 10, the protrusion 211 is likely to peel off. For this reason, by forming the protrusion 211 in a portion of the main body 10 excluding the connection portion 10a, the protrusion 211 is less likely to peel off from the main body 10.

[0038] Furthermore, the protrusion 211 is preferably formed in a curved shape without corners when viewed in a direction perpendicular to the first surface 12 (Z1-Z2 direction). In this embodiment, as shown in FIG. 2, the protrusion 211 is formed in a semicircular shape when viewed in the Z1-Z2 direction. This allows the uncoated region where the protrusion 211 is to be formed to have a curved shape when forming the insulating exterior coating 50 on the main body 10 by screen printing. In screen printing, a shape without corners is easier to print and apply than a shape with corners. Therefore, by forming the uncoated region into a curved shape without corners, it becomes easier to form the protrusion 211 to be formed in the uncoated region.

[0039] (Heat Dissipation Characteristics) FIGS. 4A to 8C are diagrams showing simulation results of the temperature distribution of the coil component. FIGS. 4A to 4C show the temperature distribution of the coil component 1A, which has a semicircular protrusion 211 with a radius of 0.2 mm, when current is applied when the coil component is mounted on the substrate S. FIGS. 5A to 5C show the temperature distribution of the coil component 1B, which has a semicircular protrusion 211 with a radius of 0.3 mm, when current is applied when the coil component is mounted on the substrate S. FIGS. 6A to 6C show the temperature distribution of the coil component 1C, which has a semicircular protrusion 211 with a radius of 0.4 mm, when current is applied when the coil component is mounted on the substrate S. FIGS. 7A to 7C show the temperature distribution of the coil component 1D, which has a semicircular protrusion 211 with a radius of 0.5 mm, when current is applied when the coil component is mounted on the substrate S. FIGS. 8A to 8C show the temperature distribution of the coil component 2, which does not have a protrusion 211, when current is applied when the coil component is mounted on the substrate S. Figures 4A, 5A, 6A, 7A and 8A show the temperature distribution as viewed obliquely, Figures 4B, 5B, 6B, 7B and 8B show the temperature distribution as viewed from above, and Figures 4C, 5C, 6C, 7C and 8C show the temperature distribution as viewed from the side.

[0040] The simulation results show that the larger the area of ​​the protrusion 211, the greater the area of ​​the region with a lower temperature overall, and the easier it is for heat to escape from the coil component to the mounting board. Note that, unlike the external electrode 21 of coil component 1, the external electrode 21 of coil components 1A to 1D shown in Figures 4A to 7C does not have other portions 212, and the portion of the external electrode 21 located on the first surface 12 consists of the protrusion 211.

[0041] Fig. 9 is a diagram showing the relationship between the area of ​​the external electrodes and the temperature of the coil component, based on the simulation results of the temperature distribution of coil components 1A, 1B, 1C, 1D, and 2 shown in Fig. 4A to Fig. 8C. The symbols of the corresponding coil components 1A, 1B, 1C, 1D, and 2 are shown in parentheses in each plot in Fig. 9.

[0042] These simulation results show that the larger the area of ​​the protrusion 211, the greater the heat dissipation effect. Here, assuming that the resistance value of the coil component before the temperature change is Rt, the resistance value after the temperature change is RT, and the temperature coefficient of the coil conductor is at, when the temperature changes from t to T, the resistance value RT after the temperature change is expressed as RT = Rt {1 + at (T - t)}. For example, compared to the coil component 2 without the protrusion 211, the coil component 1D with the widest protrusion 211 has a maximum temperature during energization that is approximately 0.3°C lower. Assuming that the resistance value Rt before the temperature change is 30 mΩ, the maximum temperature during energization is approximately 0.3°C lower, resulting in a decrease in resistance by a resistance change rate of 0.12%.

[0043] In this way, the temperature of the coil component 1 can be lowered by the protrusion 211, and the resistance value of the coil portion 30 can also be lowered, making it possible to increase the allowable current during use and improve the response characteristics.

[0044] (Other Examples of Protrusions) Fig. 10 is a plan view showing other examples of protrusions. For ease of explanation, in Fig. 10, the exterior coat 50 is indicated by a two-dot chain line, and some of the internal components of the main body 10 are indicated by dashed lines. The shape of the protrusions 211 is not limited to a semicircular shape. For example, when the coil device 1 is viewed from the Z1-Z2 direction, the protrusions 211 may have a shape that makes them easily recognizable as markers.

[0045] 10 , of the pair of external electrodes 21, 22, one external electrode 21 may have a protrusion 211, and the other external electrode 22 may have a protrusion 221. By providing the protrusions 211, 221, it is possible to improve the heat dissipation characteristics. In this case, by forming the protrusions 211, 221 to have different shapes, it is possible to make the protrusions 211, 221 function as directional markers for the coil device 1.

[0046] In this way, according to this embodiment, it is possible to provide a protrusion 211 that functions as a directional marker without increasing the number of processes, and it is possible to provide a coil component 1 that can improve its characteristics.

[0047] Although the present embodiment has been described above, the present invention is not limited to these examples. For example, the above describes a coil component 1 having a coil portion 30 built into the main body portion 10. However, other passive components, such as a resistor component having an electrical resistance portion built into the main body portion 10 or a capacitor having a capacitor built into the main body portion 10, can also be used. Materials other than those described above for each component can also be used as long as they provide similar effects to those of the present invention. Furthermore, additions, deletions, and design changes to the above-described embodiments made by a person skilled in the art, as well as appropriate combinations of features of the configuration examples of the respective embodiments, are also within the scope of the present invention as long as they incorporate the gist of the present invention.

[0048] REFERENCE SIGNS LIST 1, 1A, 1B, 1C, 1D, 2... Coil component 10... Main body portion 10a... Connection portion 11... Mounting surface 12... First surface 13a... First side surface 13b... Second side surface 13c... Third side surface 13d... Fourth side surface 21... External electrode 21a... Surface in contact with first surface 22... External electrode 30... Coil portion 31... Coil conductor portion 32... Lead portion 33... Dummy conductor portion 34... Insulating layer 50... Exterior coating 211, 221... Protruding portion 212... Other portion S... Substrate

Claims

1. A passive component having a mounting surface, a first surface opposite to the mounting surface, a first side surface and a second side surface which are a pair of side surfaces facing opposite to each other, and a third side surface and a fourth side surface which are another pair of side surfaces facing opposite to each other; a pair of external electrodes continuously formed with at least each of the first side surface and the second side surface among the four side surfaces of the main body portion and the mounting surface; one of the pair of external electrodes has a protruding portion, the protruding portion is formed to protrude toward the other external electrode side on the first surface of the main body portion, and the protruding portion is formed of the same member integrally with the one external electrode.

2. The passive component according to claim 1, wherein the one external electrode and the protruding portion are integrally formed by electrolytic plating.

3. The passive component according to claim 1, wherein the main body portion contains a magnetic material and further includes a coil portion having a polarity built therein.

4. The passive component according to claim 3, wherein a surface of the one external electrode in contact with the first surface of the main body portion is flush with the first surface.

5. The passive component according to claim 1, wherein an area of the one external electrode having the protruding portion among the pair of external electrodes is larger than an area of the other external electrode having no protruding portion.

6. The passive component according to claim 1, wherein the protruding portion is formed so as not to cover a connection portion between the first surface and the third side surface and a connection portion between the first surface and the fourth side surface in the main body portion.

7. The one external electrode including the protruding portion is formed in a region of the main body portion where there is no insulating outer coat, and in a direction orthogonal to the first surface, a portion other than a connection portion of the protruding portion with the other portion of the external electrode is formed in a curved surface shape without corners.

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