JP7063668B2 - Coil, non-contact power supply unit, and coil manufacturing method - Google Patents

Description

The present invention relates to a coil used in an electronic device, a non-contact power feeding unit using such a coil, and a method for manufacturing the coil.

Conventionally, electronic devices have been widely used, and the electronic devices are configured by using various electronic components. Examples of such electronic components include those described in Patent Documents 1-3 whose sources are shown below.

Patent Document 1 describes a coil device. This coil device is configured using a magnetic core in which metal particles are insulated by an insulating phase. In the magnetic core, a part of the insulating phase on the surface is removed, and a planned electrode portion where the surface of the metal particles is exposed within a predetermined area region and a winding core portion around which the wire is wound are formed.

Patent Document 2 describes electronic components. This electronic component includes a prime field made of a material containing particles of an insulator and a metal magnetic material, and an external electrode provided on the surface of the prime field. The prime field is provided with a coil including a coil conductor and a via conductor.

Patent Document 3 describes a surface mount inductor. This surface mount inductor includes a coil formed by winding a conducting wire and a molded body in which the coil is sealed with a sealing material containing a metal magnetic powder and a resin.

Japanese Unexamined Patent Publication No. 2016-4815 International Publication No. 2015/115180 Pamphlet Japanese Unexamined Patent Publication No. 2016-58418

In the technique described in Patent Document 1-3, the coil is formed by winding a wire, a coil conductor, or a conductor (hereinafter referred to as "wire or the like") around a core. For example, when winding a wire or the like around a core, if there is a gap between the wire or the like or the wire or the like is frayed, the electrical characteristics of the coil are affected. As described above, in the technique described in Patent Document 1-3, the coil manufacturing process may affect the electrical characteristics.

Therefore, there is a demand for a coil that has little influence on the electrical characteristics caused by the manufacturing process.

The characteristic configuration of the coil according to the present invention is to remove a magnetic resin body formed by injection molding using a resin compound containing a magnetic material and a skin layer of the magnetic resin body so that the magnetic material is exposed. The magnetic material exposed in the groove portion is provided with the groove portion formed in the above-mentioned state and the conductor layer in the state formed in the groove portion by the electroless plating treatment, and is used as a catalyst nucleus in the electroless plating treatment. It is in the point of being.

With such a characteristic configuration, it is not necessary to wind the winding around the magnetic resin body as in the so-called winding type coil, and the conductor layer can be formed at an arbitrary position. Further, since the conductor layer can be directly formed on the surface of the magnetic resin body, the distance between the conductor layer and the magnetic resin body can be made constant, and the inductor value can be stabilized. Therefore, it is possible to realize a coil having less influence on the electrical characteristics caused by the manufacturing process.

Further, it is preferable that the height from the bottom surface to the opening of the groove portion is higher than the thickness of the conductor layer from the bottom surface of the groove portion.

With such a configuration, the value of the depth of the groove can be made larger than the value of the thickness of the conductor layer, so that it is possible to prevent short circuits between the conductor layers adjacent to each other (that is, to insulate the conductor layers from each other). The creepage distance can be extended). Further, even if the conductor layers are short-circuited, only the conductive layer in the short-circuited portion needs to be removed by polishing, for example, so that the correction can be easily performed. Further, even when the conductor adheres between the grooves adjacent to each other in the magnetic resin body, the depth of the grooves is deeper than the thickness of the conductor layer, so that the conductor layers do not short-circuit each other. Further, since the distance between the conductor layers can be narrowed and the width of each conductor layer can be widened, a larger current can be passed.

Further, it is preferable that the coil further includes a through hole penetrating the magnetic resin body in the groove portion.

With such a configuration, a surface different from the surface of the magnetic resin body on which the conductor layer is formed can be used for wiring. Therefore, even when another conductor layer is formed between the terminal of the coil and the end of the conductor layer, it is possible to electrically connect the terminal of the coil and the end of the conductor layer. Become.

Further, it is preferable that the conductor layer has a nickel-plated layer containing phosphorus and a gold-plated layer laminated on the nickel-plated layer.

With such a configuration, it is possible to form a conductor layer without causing the magnetic resin body to have magnetism like a magnet.

Further, it is preferable that the magnetic resin body has a resin coating layer that covers the surface of the skin layer, and the groove portion is formed by removing the resin coating layer together with the skin layer.

With such a configuration, even if the magnetic material appears on the surface of the magnetic resin body, the resin coating layer on the surface of the magnetic resin body at the portion forming the conductor layer in the magnetic resin body can be removed. Therefore, it is possible to prevent the conductor layer from being formed except for the portion where the conductor layer is formed. That is, it becomes possible to selectively form the conductor layer.

Further, according to the coil, a non-contact power feeding coil formed by using the coil and performing power transmission based on a magnetic field, and a terminal electrode formed by being electrically connected to the conductor layer are provided. A non-contact power supply unit provided can be configured.

With such a configuration, a contactless power supply coil having excellent electrical characteristics can be configured, so that a contactless power supply unit having excellent transmission efficiency can be realized.

Further, the characteristic configuration of the method for manufacturing an electronic component according to the present invention is a magnetic resin body forming step of forming a magnetic resin body by injection molding using a resin compound containing a magnetic material, and the above-mentioned so that the magnetic material is exposed. A groove forming step for removing the skin layer of the magnetic resin body to form a groove and a conductor layer forming step for forming a conductor layer in the groove by electroless plating treatment are provided , and the exposed portion is provided in the groove forming step. The magnetic material is used as a catalyst nucleus in the electrolytic plating process .

With such a characteristic configuration, it is possible to manufacture a coil in which a gap is not formed between the magnetic resin body and the conductor layer and the conductor layer is not frayed. Therefore, it is possible to easily manufacture a coil having little influence on the electrical characteristics caused by the manufacturing process.

It is a schematic diagram of a coil. It is an exploded perspective view of a coil. It is a secondary electron image of a conductor layer by a scanning electron microscope. It is the elemental analysis result of the conductor layer.

The coil according to the present invention is configured to be manufactured at low cost. Hereinafter, the coil 1 of the present embodiment will be described. FIG. 1 is a schematic view of the coil 1, and FIG. 2 is an exploded perspective view of the coil 1. As shown in FIGS. 1 and 2, the coil 1 includes a magnetic resin body 10, a groove portion 20, and a conductor layer 30.

The magnetic resin body 10 is in a state of being formed by injection molding using a resin compound containing a magnetic material. The magnetic material is a soft magnetic material such as sendust. In the present embodiment, a mixture of such a soft magnetic material with a raw material resin for injection molding corresponds to a resin compound. The magnetic resin body 10 of the present embodiment is formed by injection molding using a predetermined mold having a shape as shown in FIGS. 1 and 2 and the resin compound. Since such injection molding is known, the description thereof is omitted here.

The step of forming the magnetic resin body 10 by injection molding using the resin compound containing such a magnetic material is referred to as a magnetic resin body forming step in the method for manufacturing the coil 1.

Here, in injection molding, when a molten material (“resin compound” in this embodiment) is injected into a cavity formed by a mold, the material flows in the cavity, but as it advances in the cavity, The material in contact with the mold surface cools and hardens more easily than the material inside the mold surface (“core layer”). The layer that cools and hardens first with respect to such a core layer is called a "skin layer". Such a skin layer 11 and a core layer 12 are schematically shown in a cross-sectional view orthogonal to the radial direction of the magnetic resin body 10 shown in # A of FIG. The thickness of such a skin layer 11 is about 10 μm.

The groove portion 20 is formed by removing the skin layer 11 of the magnetic resin body 10 so that the magnetic material is exposed. The groove portion 20 is formed at the position of the winding when the winding is wound around the magnetic resin body 10. In the present embodiment, the skin layer 11 is removed by destroying the skin layer 11 using, for example, a cutting machine such as a milling cutter. The depth of the groove portion 20 is set according to the thickness of the conductor layer 30 described later used as the winding of the coil 1, and the thickness of the conductor layer 30 is set according to the current value of the current flowing through the conductor layer 30. .. Therefore, the depth of the groove portion 20 is set according to the current value of the current flowing through the conductor layer 30. Further, the width of the groove portion 20 is also set according to the current value of the current flowing through the conductor layer 30, and can be easily changed by changing the cutter teeth of the milling cutter, for example. As a result, even a wide conductor layer 30 can be easily configured.

As described above, the groove portion 20 can be easily formed even with a highly accurate fine line pattern (for example, at intervals of 0.05 mm) by cutting using a commercially available substrate processing machine or the like. Further, by such a cutting process, the groove portion 20 can be formed not only on the same surface but also on different surfaces. That is, although not shown, it is possible to form the groove 20 on the top surface of the magnetic resin body 10 and to form the groove 20 on the side surface of the magnetic resin body 10. When the groove portion 20 is formed in this way, the groove portion 20 can be three-dimensionally formed with respect to the magnetic resin body 10.

The step of removing the skin layer 11 of the magnetic resin body 10 to form the groove 20 so that the magnetic material is exposed is referred to as a groove forming step in the method of manufacturing the coil 1. The skin layer 11 is a layer that has cooled and hardened before the core layer 12. In such a skin layer 11, the soft magnetic material (magnetic material) mixed with the raw material resin may not be uniformly distributed. In such a case, when forming the conductor layer 30 described later, the magnetic material cannot be used as a catalyst nucleus in the electroless plating treatment, and the conductor layer 30 cannot be formed at the desired location. Therefore, the skin layer 11 is removed in the groove forming step.

The conductor layer 30 is in a state of being formed in the groove 20 by electroless plating. The conductor layer 30 corresponds to the winding in the coil 1 as described above. Here, as described above, the groove portion 20 is formed so that the skin layer 11 of the magnetic resin body 10 is removed to expose the magnetic material. The conductor layer 30 is formed on the surface of the magnetic resin body 10 by activating the exposed magnetic material as a catalyst nucleus and performing electroless plating treatment.

For such electroless plating treatment, for example, electroless copper plating treatment can be used. FIG. 3 shows a secondary electron image of the conductor layer 30 formed by the electroless copper plating process by a scanning electron microscope. Further, FIG. 4 is an elemental analysis result of the region in which the secondary electron image in FIG. 3 was acquired by the energy dispersive X-ray spectroscopy. In both FIGS. 3 and 4, the electron acceleration voltage is acquired as 15 kV. Since the peak of copper (Cu) is large as shown in FIG. 4, it can be seen that the conductor layer 30 made of copper is appropriately formed in the secondary electron image shown in FIG. 3 by electroless plating. Understand.

The conductor layer 30 may have a nickel-plated layer containing phosphorus and a gold-plated layer laminated on the nickel layer. This makes it possible to form the conductor layer 30 without causing the magnetic resin body 10 to be magnetized like a permanent magnet. The phosphorus content of the nickel-plated layer is preferably 8% or more (that is, a high phosphorus content of 8% or more is preferable). By using such high phosphorus, it does not become magnetized.

It is preferable that the height from the bottom surface of the groove portion 20 to the opening of the groove portion 20 is higher than the thickness of the conductor layer 30 from the bottom surface of the groove portion 20. As a result, it is possible to prevent short circuits between the conductor layers 30 adjacent to each other, and it is possible to shorten the distance between the conductor layers 30. Therefore, the conductor layer 30 can be formed at a high density, which can contribute to the compactification of the coil 1.

Further, even if the conductor layers 30 adjacent to each other are short-circuited, only the short-circuited conductor layer 30 is removed (for example, by polishing) to correct the short-circuited conductor layer 30 while leaving the regular conductor layer 30. Is possible. Further, even if a conductor is attached to the surface of the magnetic resin body 10 located between the conductor layers 30 adjacent to each other, the conductor layers 30 adjacent to each other may be bridged by the attached conductor. Since there is no such thing, there is no need to apply insulation treatment.

As shown in # B (enlarged view of #A) in FIG. 1 described above, the portion of the conductor layer 30 in contact with the wall surface of the groove 20 is located in the extending direction of the conductor layer 30 (diameter of the magnetic resin body 10). A tapered fillet 32 is formed in a cross section orthogonal to the direction), and it is preferable to set the thickness of the conductor layer 30 described above to include such a fillet 32.

Here, as shown in FIG. 1, when the conductor layer 30 is formed in a spiral shape on the top surface of the magnetic resin body 10, the electrode 40 of the conductor layer 30 is arranged on the side surface of the magnetic resin body 10. , It is necessary to prevent a short circuit with the conductor layer 30 on the outer side in the radial direction. Therefore, it is preferable to provide a pair of through holes 50 that penetrate the magnetic resin body 10 in the groove portion 20. As a result, the auxiliary conductor layer 31 is formed from the end of the conductor layer 30 on the inner side in the radial direction to a surface different from the top surface of the magnetic resin body 10 through one through hole 50, and the conductor layer 30 on the outer side in the radial direction is formed. After avoiding the above, the conductor layer 30 can be formed by returning to the top surface of the magnetic resin body 10 at the other through hole 50. With this configuration, for example, the electrodes 40 can be provided close to each other on the side surface of the magnetic resin body 10.

Since such a through hole 50 can be formed in a subsequent step (a step after the magnetic resin body 10 is injection molded), the structure of the mold used for forming the magnetic resin body 10 is simplified. be able to.

The through hole 50 can be formed by using a known via forming technique after forming the groove portion 20 in the magnetic resin body 10. Further, by applying the electroless plating treatment to the through hole 50 or by mounting a known through hole pin in the through hole 50, both sides of the through hole 50 in the axial direction can be easily electrically connected. Is possible. Therefore, it is not necessary to make a hole in the magnetic resin body 10 in advance. Further, in the auxiliary conductor layer 31, similarly to the conductor layer 30 described above, the skin layer 11 is removed so that the magnetic material is exposed at the position where the auxiliary conductor layer 31 is formed to form the groove portion 20, and electroless electrolysis is performed. It can be formed by applying a plating treatment. The through hole 50 may be formed at the same time as the molding of the magnetic resin body 10.

The step of forming the conductor layer 30 in the groove 20 by such electroless plating treatment is referred to as a conductor layer forming step in the method of manufacturing the coil 1.

By configuring the coil 1 as described above, it is possible to realize a coil having excellent electrical characteristics at low cost.

[Other embodiments]
In the above embodiment, in FIGS. 1 and 2, the groove portion 20 and the conductor layer 30 are shown to be formed on the top surface of the magnetic resin body 10, but the groove portion 20 and the conductor layer 30 are formed on the side surface of the magnetic resin body 10. It can be formed, or it can be formed on both the top surface and the side surface.

In the above embodiment, the groove portion 20 has been described as being formed by removing the skin layer 11 of the magnetic resin body 10 so that the magnetic material is exposed, but the magnetic resin body 10 is the surface of the skin layer 11. It is also possible to form it so as to have a resin coating layer covering the above. In such a case, the groove portion 20 may be formed by removing the resin coating layer together with the skin layer 11. As a result, even if the magnetic material is exposed on the surface of the magnetic resin body 10, the entire surface is once covered with the resin coating layer, and only the portion forming the conductor layer 30 can be exposed again. Therefore, even when the electroless plating treatment is applied, it is possible to prevent the conductor layer 30 from being formed in an unnecessary portion.

In the above embodiment, the groove portion 20 has been described as being formed by cutting, but the skin layer 11 may be removed by using a laser, or the skin layer 11 may be removed by etching. Further, the skin layer 11 may be selectively melted and removed by heat.

In the above embodiment, the magnetic resin body 10 formed by injection molding has been described as an example, but the core of a so-called CT (Current Transformer) type current sensor is formed by injection molding using a ferrite-based plastic magnet material. It is also possible to form the conductor layer 30 on the core as described in the above embodiment.

For example, it includes a non-contact power feeding coil formed by using the coil 1 described in the above embodiment and performing power transmission based on a magnetic field, and a terminal electrode formed by being electrically connected to the conductor layer 30. It is also possible to configure a non-contact power supply unit.

In a general winding coil, when a distance is generated between the winding and the core, the inductor value fluctuates depending on the transmittance of the magnetic material. Therefore, in non-contact power supply, the resonance adjustment capacitor is adjusted according to the inductor value. There is a need. In particular, in the case of non-contact feeding of the magnetic resonance method, it is necessary to strictly adjust the resonance conditions, and fluctuation of the inductor value is not preferable. According to the coil 1 described in the above embodiment, the inductor value is stable, so that adjustment is not required for each individual. In addition, electric power can be efficiently transmitted from the primary coil. Further, by forming the non-contact power feeding coil three-dimensionally, the directional characteristic of the power feeding is eliminated, and the magnetic resin body 10 works to collect the magnetic flux, so that the power can be omnidirectionally supplied only on the power receiving side. .. Further, it is also possible to form a land on the magnetic resin body 10 for mounting a resonance adjusting capacitor that adjusts resonance with the non-contact power feeding coil. Such a land can also be formed in the same manner as the conductor layer 30 described above, and the non-contact power feeding coil can be miniaturized.

In the above embodiment, the coil 1 provided with the groove portion 20 and the conductor layer 30 has been described. However, when manufacturing electronic components other than the coil 1 and patterning a circuit board, the method for forming the groove portion 20 and the conductor layer 30 described above. It is also possible to use.

INDUSTRIAL APPLICABILITY The present invention can be used for a coil used in an electronic device, a non-contact power feeding unit using such a coil, and a method for manufacturing a coil.

1: Coil 10: Magnetic resin body 11: Skin layer 20: Groove 30: Conductor layer 50: Through hole

Claims (7)

A magnetic resin body formed by injection molding using a resin compound containing a magnetic material,
The groove portion formed by removing the skin layer of the magnetic resin body so that the magnetic material is exposed, and the groove portion.
The conductor layer formed in the groove by electroless plating and
Equipped with
The magnetic material exposed in the groove is a coil used as a catalyst nucleus in the electroless plating process . The coil according to claim 1, wherein the height from the bottom surface to the opening of the groove portion is higher than the thickness of the conductor layer from the bottom surface of the groove portion. The coil according to claim 1 or 2, further comprising a through hole penetrating the magnetic resin body in the groove portion. The coil according to any one of claims 1 to 3, wherein the conductor layer has a nickel-plated layer containing phosphorus and a gold-plated layer laminated on the nickel-plated layer. The magnetic resin body has a resin coating layer that covers the surface of the skin layer.
The coil according to any one of claims 1 to 4, wherein the groove portion is formed by removing the resin coating layer together with the skin layer. A non-contact power feeding coil formed by using the coil according to any one of claims 1 to 5 and performing power transmission based on a magnetic field.
A terminal electrode formed by being electrically connected to the conductor layer,
Non-contact power supply unit equipped with. A magnetic resin body forming step of forming a magnetic resin body by injection molding using a resin compound containing a magnetic material,
A groove forming step of removing the skin layer of the magnetic resin body to form a groove so that the magnetic material is exposed, and a groove forming step.
A conductor layer forming step of forming a conductor layer in the groove by electroless plating, and
Equipped with
A method for manufacturing a coil in which the exposed magnetic material in the groove forming step is used as a catalyst nucleus in the electroless plating process .

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