JP2014027094A - Coil module and power receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil module in which the size and thickness are reduced, by suppressing heat generation of an antenna coil.SOLUTION: A coil module 10 includes a spiral coil 2 formed by winding a conductor 1 spirally, and a magnetic resin layer 4a composed of a resin containing magnetic particles. The spiral coil 2 has lead-out parts 3a, 3b at the end of the conductor 1, and a secondary circuit of a non-contact charging circuit is constituted by connecting a rectifier circuit, or the like, with the lead-out parts 3a, 3b. Preferably, the magnetic resin layer 4a is formed by embedding the spiral coil 2 entirely.

Description

  The present invention relates to a coil module including a spiral coil and a magnetic shield layer made of a magnetic shield material, and more particularly to a coil module having a magnetic resin layer containing magnetic particles as a magnetic shield layer.

  In recent wireless communication devices, a plurality of RF antennas such as a telephone communication antenna, a GPS antenna, a wireless LAN / BLUETOOTH (registered trademark) antenna, and an RFID (Radio Frequency Identification) are mounted. In addition to these, with the introduction of non-contact charging, antenna coils for power transmission have also been mounted. Examples of the power transmission method used in the non-contact charging method include an electromagnetic induction method, a radio wave reception method, and a magnetic resonance method. These all use electromagnetic induction and magnetic resonance between the primary side coil and the secondary side coil, and the above-described RFID also uses electromagnetic induction.

  Even if these antennas are designed so that the maximum characteristics can be obtained at a target frequency with a single antenna, it is difficult to obtain the target characteristics when actually mounted on an electronic device. This is because the magnetic field component around the antenna interferes (couples) with the surrounding metal and the like, and the inductance of the antenna coil is substantially reduced, so that the resonance frequency is shifted. In addition, the reception sensitivity is lowered due to a substantial decrease in inductance. As countermeasures against these problems, by inserting a magnetic shield material between the antenna coil and the metal existing around it, the magnetic flux generated from the antenna coil is collected on the magnetic shield material, thereby reducing the interference caused by the metal. it can.

JP 2008-210861 A

  In addition to the general problems of the antenna described above, in electromagnetic induction type non-contact charging, it is necessary to improve the transmission efficiency of transmission power from the primary side to the secondary side while suppressing heat generation of the antenna coil. In consideration of mounting on an electronic device such as a portable terminal device, it is most important to reduce the size and thickness of the antenna coil. For example, in Patent Document 1, as shown in FIG. 12, an adhesive layer 41 in which a magnetic flux concentrating magnetic shielding sheet (herein described as a magnetic sheet 4b) is applied to a spiral coil-shaped loop antenna element 2 and an adhesive is applied. The coil module 50 of the structure affixed via is described. Further, in order to reduce the thickness of the coil module for use in electromagnetic induction type non-contact charging, a notch 21 is provided in the magnetic sheet 4b formed in a sheet shape with ferrite or the like so that the lead portion 3a of the coil conductor 1 is provided. The technique of accommodating in the notch 21 is described.

  However, in a conventional coil module including a spiral coil used as an antenna coil and a magnetic shield material disposed adjacent to the spiral coil, in order to further reduce the size and thickness of the coil module, the coil winding The only way to do this is to make it thinner or make the magnetic shield material thinner. If the coil winding is made thin, the resistance value of the conducting wire (mainly Cu is used) increases, and the coil temperature rises. If the temperature inside the casing of the electronic device rises due to heat generated by the coil, a space for cooling is required, which hinders downsizing and thinning. Also, if the magnetic shield material is made smaller or thinner, the magnetic shield effect is reduced, and eddy currents are generated in the metal around the antenna coil (for example, the outer case of the battery pack, etc.), thus reducing transmission efficiency. Problem arises.

  Further, in the conventional coil module, since the adhesive is used to fix the spiral coil to the magnetic sheet in the manufacturing process, the manufacturing process is complicated, and the thickness of the layer coated with the adhesive is also large. Since there exists, there exists a problem of increasing the thickness of a coil module. Furthermore, in the conventional coil module, since the magnetic sheet is made of brittle ferrite, a protective sheet made of an insulating material may be stuck on the surface of the magnetic sheet for the purpose of preventing damage due to external force. Therefore, a protective sheet sticking process is required, and there is a problem that the thickness of the coil module increases by the thickness of the protective sheet.

  Therefore, an object of the present invention is to provide a coil module that suppresses heat generation of an antenna coil and realizes a small size and a thin shape.

  As means for solving the above-described problems, a coil module according to the present invention includes a magnetic shield layer containing a magnetic material and a spiral coil. The magnetic shield layer has a magnetic resin layer containing magnetic particles, and at least a part of the spiral coil is embedded in the magnetic resin layer.

  The coil module according to the present invention has a magnetic resin layer in which at least a part of the magnetic shield layer is embedded in the magnetic resin layer, so that the heat dissipation effect by the magnetic resin layer can be obtained and the size and thickness can be reduced. It becomes possible.

(A) is a top view of the coil module which is 1st Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. (A) is a perspective view which shows the external appearance of the coil module model for simulation comprised in order to evaluate the characteristic of the coil module to which this invention was applied. (B) is a perspective view showing the appearance of a simulation coil module model configured for comparison with the characteristics of the coil module of the present invention. (A) is a top view which shows the modification of the coil module of 1st Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. (A) is a top view of the coil module which is 2nd Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. (A) is a top view which shows the modification of the coil module of 2nd Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. (A) is a top view which shows the modification of the coil module of 2nd Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. (A) is a top view which shows the modification of the coil module of 2nd Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. (A) is a top view which shows the modification of the coil module of 2nd Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. (A) is a top view which shows the modification of the coil module of 2nd Embodiment to which this invention was applied. (B) is a sectional view taken along line AA ′ in FIG. It is a block diagram of the measurement circuit comprised in order to compare the characteristic of the coil module to which this invention was applied, and the conventional coil module. (A) is a top view of the conventional coil module. (B) is a sectional view taken along line AA ′ in FIG. (A) is a top view of the conventional coil module described in patent document 1. FIG. (B) is a sectional view taken along line AA ′ in FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited only to the following embodiment, Of course, a various change is possible in the range which does not deviate from the summary of this invention.

[First Embodiment]
<Configuration of coil module>
As shown in FIGS. 1A and 1B, a coil module 10 includes a spiral coil 2 formed by winding a conducting wire 1 in a spiral shape and a magnetic resin layer 4a made of a resin containing magnetic particles. With. The spiral coil 2 has lead-out portions 3a and 3b at the ends of the conducting wire 1, and constitutes a secondary side circuit of a non-contact charging circuit by connecting a rectifier circuit or the like to the lead-out portions 3a and 3b. As shown in FIG. 1B, the outer diameter of the spiral coil 2 is such that the lead-out portion 3a on the inner diameter side of the spiral coil 2 passes through the lower surface side of the wound conductive wire 1 and intersects the conductive wire 1. Pulled out to the side. The magnetic resin layer 4a is preferably formed by embedding the entire spiral coil 2. Here, since the thickness of the magnetic resin layer 4a can be made equal to or less than the thickness of the conducting wire 1 × 2, the thickness of the coil module 10 can be made to be the thickness of the conducting wire 1 × 2.

  The magnetic resin layer 4a includes magnetic particles made of soft magnetic powder and a resin as a binder. The magnetic particles include oxide magnetic materials such as ferrite, Fe-based, Co-based, Ni-based, Fe-Ni-based, Fe-Co-based, Fe-Al-based, Fe-Si-based, Fe-Si-Al-based, Fe- Ni-Si-Al-based crystal system, microcrystalline metal magnetic material, or Fe-Si-B system, Fe-Si-BC system, Co-Si-B system, Co-Zr system, Co-Nb And Co—Ta based amorphous metal magnetic particles. As the magnetic particles, spherical or flat powder having a particle size of several μm to several tens of μm is used, but crushed powder may be mixed. In the case of the above-described metal magnetic material, the complex permeability has frequency characteristics, and loss occurs due to the skin effect when the operating frequency becomes high, so the particle size and shape are adjusted according to the frequency band to be used. . Further, the inductance value of the coil module 10 is determined by the real part magnetic permeability (hereinafter simply referred to as magnetic permeability) of the magnetic material, but the magnetic permeability can be adjusted by the mixing ratio of the magnetic particles and the resin. . Since the relationship between the average magnetic permeability of the magnetic resin layer 4a and the magnetic permeability of the magnetic particles to be blended generally follows the logarithmic mixing rule with respect to the blending amount, the volume filling rate at which the interaction between the particles increases is 40 vol% or more. It is preferable that Note that the heat conduction characteristics of the magnetic resin layer 4a also improve as the filling rate of the magnetic particles increases.

  The magnetic resin layer 4a is not limited to the case where it is composed of a single magnetic material. Two or more kinds of magnetic materials may be mixed and used, and a magnetic resin layer may be formed by stacking in multiple layers. Even if the same magnetic material is used, a plurality of magnetic particle diameters and / or shapes may be used. It may be selected and mixed, or may be laminated in multiple layers. Since these variations are possible, desired magnetic characteristics can be realized.

  As the binder, a resin that is cured by heat, ultraviolet irradiation, or the like is used. As the binder, for example, a known material such as a resin such as an epoxy resin, a phenol resin, a melamine resin, a urea resin, or an unsaturated polyester, or a rubber such as silicone rubber, urethane rubber, acrylic rubber, butyl rubber, or ethylene propylene rubber is used. be able to. Needless to say, it is not limited to these. An appropriate amount of a surface treatment agent such as a flame retardant, a reaction modifier, a crosslinking agent, or a silane coupling agent may be added to the above-described resin or rubber.

  The lead wire 1 forming the spiral coil 2 has a charge output capacity of about 5 W, and when used at a frequency of about 120 kHz, Cu or Cu having a diameter of 0.20 mm to 0.45 mm as a main component It is preferable to use a single wire made of Alternatively, in order to reduce the skin effect of the conducting wire 1, a parallel line obtained by bundling a plurality of fine wires thinner than the above-described single wire, a knitted wire may be used, one layer using a thin rectangular wire or a flat wire, Or it is good also as alpha winding of 2 layers.

<Manufacturing method of coil module>
The magnetic resin layer 4a is formed by placing the spiral coil 2 on a mold that is the final shape of the coil module 10, and kneading the above-described magnetic particles such as ferrite and resin or rubber as a binder. Inject and mold. Then, the coil module 10 is formed by curing the resin or the like by heating or irradiating ultraviolet rays thereafter. Alternatively, a predetermined amount of resin or the like is injected into the mold of the coil module 10 and the spiral coil 2 is embedded in a soft resin or the like before being cured, and then the resin or the like is cured by heating or ultraviolet irradiation. The coil module 10 can be formed.

  Further, the magnetic resin layer 4a is formed in a sheet shape in advance, the spiral coil 2 is placed on the sheet, and the coil module 10 in which the spiral coil 2 is embedded is formed by applying pressure or heat treatment. You can also.

  The amount of resin or the like may be an amount that completely embeds the spiral coil 2 as shown in FIG. 1, or may be an amount that exposes the conductor 1 and a part of the lead portion 3b. Further, the position of the resin or the like may be a position where the region on the lower surface side of the conductor 1 and the outer portion of the spiral coil 2 are filled. As will be described later, the region on the lower surface side of the conductor 1 and the inner diameter of the spiral coil 2. The position which fills a part may be sufficient.

  According to such a manufacturing method, it is not necessary to use an adhesive when fixing the spiral coil 2 and the magnetic resin layer 4a. Accordingly, the number of steps for applying the adhesive is reduced, and the coil module 10 can be made thinner by the amount of the adhesive layer formed by applying the adhesive. In addition, since the resin as described above is kneaded in the magnetic resin layer 4a, it does not cause breakage such as cracking against an external impact, so it is necessary to stick a protective sheet on the surface. There is no. Therefore, the protective sheet sticking process can be reduced, and an increase in the thickness of the coil module applied to the protective sheet can be suppressed.

<Characteristic comparison with conventional coil module>
The characteristics of the coil module 10 according to the present invention were evaluated using a simulation program. FIG. 2 is a perspective view showing the shape of the coil module used for the analysis.

  As shown in FIG. 2A, in the coil module 10 of the present invention, the entire spiral coil 2 in which the conducting wire 1 is wound in a circular shape is embedded in the magnetic resin layer 4a. The lead wire 1 of the spiral coil 2 is a flat lead wire having a line width of 1 mm and a wire thickness of 0.2 mm. A spiral coil 2 is configured by winding such a conducting wire 1 for three turns. The magnetic resin layer 4a was configured to have a size of 43 mm × 43 mm × 0.75 mm. As described above, the electrical characteristics such as the magnetic permeability of the magnetic resin layer 4a can be changed depending on the material of the magnetic particles, the particle shape, the particle diameter, and the mixing ratio with the resin (or rubber, etc.). The magnetic permeability of the layer 4a was simulated for four types of 15, 20, 25, and 30.

  As shown in FIG. 2 (B), the conventional coil module 40 has the same spiral coil 2 as that shown in FIG. 2 (A) on a magnetic sheet 5 made of Ni—Zn ferrite having a permeability of 100. It was formed through an adhesive layer with a thickness of 15 mm. The magnetic sheet 5 is 43 mm × 43 mm × 0.4 mm in size, and has a structure in which a cutout portion 21 is provided at a location where the lead-out portion 3 a from the inner diameter side of the spiral coil 2 overlaps the conductor 1 to accommodate the lead-out portion 3 a. did. Since the thickness of the magnetic sheet 5 is 0.4 mm, the thickness of the adhesive layer is 0.15 mm, and the thickness of the conductive wire is 0.2 mm, the total thickness of the coil module is 0.75 mm, This is the same as the coil module shown in FIG.

  2A and 2B, assuming that the coil module is mounted in an electronic device, a 40 mm × 40 mm × 0.3 mm thin Al plate is used for each coil magnetism. The resin layer 4a and the magnetic sheet 5 are opposed to each other at a distance of 0.1 mm from the surface opposite to the spiral coil installation side.

  As described above, Table 1 shows the results of calculating the inductance and Q by simulation for coil modules having exactly the same external dimensions. In Table 1, numerical values normalized with reference to the comparative example are shown.

  As shown in Table 1, the coil module 10 according to the present invention has characteristics equivalent to or better than those of the conventional coil module 40 including a magnetic sheet having a permeability of 100 by setting the permeability to 30 or more with respect to inductance. Recognize. About Q, even if the magnetic permeability is 15, it has shown that it is equivalent to the characteristic of the conventional coil module 40.

  Therefore, the coil module 10 of the present invention having a thickness equivalent to that of the conventional coil module 40 is greater than that of the conventional coil module 40 by adjusting the mixing ratio of the magnetic particles and setting the magnetic permeability to an appropriate value. It is possible to realize the characteristics.

  As described above, if the coil module 10 of the present invention has the same thickness and the same inductance as the conventional coil module 40, a higher Q coil can be realized. A high Q value is expected to improve transmission efficiency when coupled with the primary coil.

  Furthermore, since the spiral coil 2 is embedded in the magnetic resin layer 4a, the Joule heat generated in the conductor 1 is greatly reduced due to the high thermal conductivity of the magnetic resin layer 4a containing a large amount of magnetic material having high thermal conductivity. It becomes possible to dissipate heat effectively. Due to the highly efficient heat dissipation structure, when mounted in an electronic device, the coil module 10 of the present invention can be mounted in a narrower mounting space, which is suitable for the demand for downsizing and thinning of the electronic device. Yes.

  In the conventional coil module 40, as shown in FIG. 11 (A) and FIG. 11 (B), the lead-out part 3a from the inner diameter side of the spiral coil 2 of the conducting wire 1 intersects the other conducting wire 1 and pulls it out. Therefore, the thickness of the coil module is increased by the thickness of the lead-out portion 3a. Further, in order to fix the spiral coil 2 and the magnetic sheet 42, it is necessary to provide an adhesive layer 41 between the spiral coil 2 and the magnetic sheet 42, and the thickness of the coil module is also increased by the adhesive layer 41. Become. Further, in the case of the coil module 50 described in Patent Document 1, as shown in FIG. 12, the portion of the lead-out portion 3a is accommodated in the notch portion 21 provided in the magnetic sheet 4b. Although it does not become, the part of the adhesive bond layer 41 becomes thick. In the coil module 10 of the present invention, when the configuration shown in FIGS. 1 and 3 is used, the magnetic resin layer 4a can fix the spiral coil 2, so that the adhesive layer 41 is not required, contributing to a reduction in thickness. To do.

[Modification of First Embodiment]
In the first embodiment of the present invention, even if the magnetic resin layer 4a of the coil module 10 does not embed the entire spiral coil 2, the magnetic resin layer 4a is formed on the magnetic circuit of the spiral coil 2. In this case, it is possible to improve performance such as improvement of inductance.

  As shown in FIGS. 3 (A) and 3 (B), the coil module 10 of the present invention includes a spiral coil 2 formed by winding a conducting wire 1 in a spiral shape, and a magnetic material comprising a resin containing magnetic particles. The magnetic resin layer 4a is formed so that the lead portion 3a is buried on one surface of the inner diameter portion 11 of the spiral coil 2 and the spiral coil 2. The spiral coil 2 has lead-out portions 3a and 3b at the ends of the conducting wire 1, and constitutes a secondary side circuit of a non-contact charging circuit by connecting a rectifier circuit or the like to the lead-out portions 3a and 3b. As shown in FIG. 3B, the lead-out portion 3a on the inner diameter side of the spiral coil 2 passes through the lower surface side of the wound conducting wire 1 and is drawn to the outer diameter side of the spiral coil 2 as described above. This is the same as in the case of FIG.

  In this way, the magnetic resin layer 4a is disposed in an arbitrary amount of embedding at an arbitrary position around the surface of the spiral coil 2 opposite to the surface facing the spiral coil 2 when communicating with the spiral coil 2. And by adjusting the characteristics of the magnetic material such as magnetic permeability, which is set by the material of the magnetic particles, the mixing ratio of the magnetic particles and the resin (or rubber, etc.), the shape of the magnetic particles, the particle size, etc. It is possible to form the coil module 10 having the following characteristics and shape. With such a degree of freedom, it is possible to effectively utilize the mounting space in a narrow electronic device and contribute to weight reduction. In addition, even with a smaller amount of the magnetic resin layer 4a, it is possible to achieve the same electrical characteristics as the conventional coil module, and the conductor 1 is partially embedded in the magnetic resin layer 4a. A high heat dissipation effect can also be expected.

[Second Embodiment]
<Configuration of coil module>
The coil module of the present invention can be constituted by a multilayer magnetic shield layer using two or more kinds of magnetic materials. In particular, by combining with a magnetic sheet having a high magnetic permeability, it is possible to realize improvement in electrical characteristics and further reduction in size and thickness.

  As shown in FIGS. 4A and 4B, the coil module 20 of the present invention includes a magnetic sheet 4b formed using a magnetic material having a high magnetic permeability, such as Ni—Zn ferrite, and a magnetic sheet 4b. A spiral coil 2 placed thereon and a magnetic resin layer 4a formed to embed the spiral coil 2 are provided. The magnetic shield layer 4 is a laminate of a magnetic sheet 4b and a magnetic resin layer 4a. The spiral coil 2 is drawn out so that the lead-out portion 3 a from the inner diameter side of the spiral coil 2 intersects the other conducting wire 1. The magnetic resin layer 4a embeds the entire spiral coil 2 other than the intersecting portion of the lead portion 3a. Although not shown, when the magnetic sheet 4b is formed of a material that is easily broken, such as ferrite, a protective sheet is attached to the surface of the magnetic sheet 4b opposite to the surface on which the spiral coil 2 is placed. You may do it.

  The magnetic resin layer 4a includes magnetic particles made of soft magnetic powder and a resin as a binder, and is the same as in the first embodiment. That is, magnetic oxides such as ferrite, Fe-based, Co-based, Ni-based, Fe-Ni-based, Fe-Co-based, Fe-Al-based, Fe-Si-based, Fe-Si-Al-based, Fe-Ni- Crystal system such as Si-Al system, microcrystalline metal magnetic material, or Fe-Si-B system, Fe-Si-BC system, Co-Si-B system, Co-Zr system, Co-Nb system, Co-Ta based amorphous metal magnetic particles. As the magnetic particles, spherical or flat powder having a particle size of several μm to several tens of μm is used, but crushed powder may be mixed. In the case of the metal magnetic material described above, loss occurs due to the skin effect when the frequency increases due to the frequency dependence of the complex permeability, and therefore the particle size and shape are adjusted according to the frequency band to be used.

  The binder for the magnetic resin layer 4a is the same as that in the first embodiment. That is, a resin that is cured by heat, ultraviolet irradiation, or the like is used. As the binder, for example, a known material such as a resin such as an epoxy resin, a phenol resin, a melamine resin, a urea resin, or an unsaturated polyester, or a rubber such as silicone rubber, urethane rubber, acrylic rubber, butyl rubber, or ethylene propylene rubber should be used. Needless to say, but not limited to these.

  The magnetic sheet 4b is generally made of ferrite having a high electrical resistivity, but may be made of a magnetic material similar to the magnetic particles, for example, an amorphous metal magnetic material such as Fe-based or Co-based, such as Sendust, Permalloy, etc. Of course, it is possible to use a Fe-based crystalline metal magnetic material, a microcrystalline magnetic material, or the like.

<Method for Manufacturing Coil Module of Second Embodiment>
Next, an example of a method for producing the coil module 10 according to the second embodiment of the present invention will be described. First, magnetic sheets 4b and 14b are prepared. Here, an example in which ferrite is used as the magnetic sheets 4b and 14b will be described.

  The ferrite raw material mixture is pressed into a mold and molded, fired to form bulk ferrite, and then molded into a sheet by slicing.

  The magnetic sheet 4b molded in this manner is further disposed in the mold, and after placing the spiral coil 2 on the magnetic sheet 4b, the magnetic resin is injected into the mold. An adhesive may be applied on the magnetic sheet 4b to fix the spiral coil 2 when it is placed on the magnetic sheet 4b, but the magnetic resin before curing is used to fix the spiral coil 2 instead of the adhesive. It is preferable to use it. Thereafter, the coil module 20 is removed from the mold by heating or ultraviolet irradiation to cure the magnetic resin. As in the case of the first embodiment, the spiral coil 2 may be embedded after injecting the magnetic resin.

  Alternatively, the spiral coil 2 is embedded at the position where the magnetic resin is injected into the mold, and is placed so as to cover the magnetic resin layer 4a with the sintered magnetic sheet 4b, and then the magnetic resin is cured. May be.

  When forming the magnetic sheet 4b, other methods can be used regardless of slicing. For example, a ferrite slurry prepared by mixing ferrite raw material powder and a binder is molded into a thin sheet by a doctor blade method (green sheet), and then the green sheet molded into a predetermined shape by a punching die is sintered. Alternatively, a ferrite sheet method may be used. The coil module of the present invention can be formed by performing the same processing as described above on the sintered ferrite magnetic sheet 4b.

  As will be described later, the notch 21 may be formed in the magnetic sheet 4b. In this case, the notched portion 21 may be formed in a bulk state after sintering the bulk ferrite, or the notched portion 21 may be formed by grooving after slicing the magnetic sheet 4b. Further, when the magnetic sheet 4b is formed from a green sheet, it is possible to form the magnetic sheet 4b in which the notch 21 is formed by preparing a punching die that takes into account the notch 21 in advance.

[Modification of Second Embodiment]
5 (A) and 5 (B) are diagrams showing a modification in the case where the lead-out portion 3a from the inner diameter of the spiral coil 2 intersects and pulls out from the lower portion of the other conductor 1, that is, the magnetic sheet 4b side. . In this modification, since the spiral coil 2 including the lead-out portion 3a is embedded in the magnetic resin layer 4a, the thickness of the magnetic resin layer 4a is larger than that in the case of FIG. Since the magnetic resin layer 4a is thick, the inductance is increased and the electrical characteristics of the coil are improved. Needless to say, even in the case of FIG. 4, the magnetic resin layer 4 a can be made as thick as two conductors 1.

  6A and 6B correspond to the lead-out portion 3a of the magnetic sheet 4b when the lead-out portion 3a from the inner diameter of the spiral coil 2 is pulled out from the lower part of the other conductor 1, that is, the magnetic sheet 4b side. It is a figure which shows the modification which reduced thickness by forming the notch part 21 in the location to do. Since the lead-out part 3a is embedded in the notch part 21, the thickness of the coil module 20 can be reduced by the thickness of the conducting wire 1 or the thickness of the magnetic sheet 4b.

  7A and 7B are not limited to the portion corresponding to the lead-out portion 3a when the notch 21 is formed at the location corresponding to the lead-out portion 3a of the magnetic sheet 4b. It is a figure which shows the modification which extended the notch part 21 over the full length.

  6 and 7, the notch 21 is filled with the magnetic resin, but needless to say, the notch 21 may not be filled with the magnetic resin.

  As shown in FIGS. 8A and 8B, the magnetic resin layer 4a does not have to be formed so as to embed the entire spiral coil 2, but fills the inner diameter portion 11 of the spiral coil 2. You may make it form.

  As shown in FIGS. 9A and 9B, the magnetic resin layer 4 a in which the spiral coil 2 is embedded and the magnetic sheet 4 b may be bonded via an adhesive layer 41.

  In order to confirm the effectiveness of the present invention, the coil module 20 of the present invention and the conventional coil module 40 are prepared, the electrical characteristics are evaluated, and the respective coil modules 20 and 40 are used as non-contact charging circuits. It mounted and the temperature rise of the coil modules 20 and 40 was evaluated.

  An evaluation circuit used for evaluating the temperature rise of the coil modules 20 and 40 is shown in FIG. The evaluation circuit includes a primary side switching circuit 32 to which an AC power supply 33 is connected, a power transmission coil 30 driven by the primary side switching circuit, coil modules 20 and 40 used as secondary power reception coils, and a coil module 20. , 40, and a constant power load device 35. The power transmission coil 30 and the coil modules 20 and 40 are arranged to face each other and are fixed with an interval of 2.5 mm. On the opposite side of the coil modules 20 and 40 facing the power transmission coil 30, a 0.3 mm thick Al thin plate having an area substantially equal to the area of the coil modules 20 and 40 was placed and fixed. In order to measure the temperature of the coil modules 20 and 40, a thermocouple was attached to the surface of the coil modules 20 and 40, and the temperature was measured with a thermocouple thermometer 36. The Al thin plate 31 is for simulating a metal battery outer case when the coil modules 20 and 40 are mounted on an actual electronic device.

[Example 1]
The configuration of the coil module is the configuration shown in FIG. 4, the magnetic sheet 4 b, the spiral coil 2 placed on the magnetic sheet 4 b, and the magnetic resin layer 4 a formed so as to embed the entire spiral coil 2. Is provided. The lead portion 3 a is drawn from the inner diameter side of the spiral coil 2 so as to cross the upper side of the conducting wire 1. Since the magnetic resin layer 4a covers the entire spiral coil 2 other than the intersecting portion of the lead portion 3a, the thickness of the magnetic resin layer 4a is 0.4 mm. The magnetic sheet 4b and the spiral coil 2 were fixed via an adhesive layer as in the comparative example described later (in this comparative experiment, since the adhesive layer is extremely thin of about 10 μm, the total coil module) Not included in thickness). The lead wire 1 of the spiral coil 2 is a round copper coil having an inner diameter of 35 mm using a Cu round wire (1 type) having a diameter of 0.4 mm. The number of turns is 10T. As the magnetic sheet 4b, a Mn—Zn ferrite sheet having a size of 50 mm × 50 mm and a thickness of 0.4 mm was used. The magnetic permeability of this Mn—Zn ferrite is 1000. As the magnetic resin layer 4a, a silicone resin containing 65% Fe-based spherical amorphous (D50 = 10 μm) was used.

[Example 2]
The configuration of the spiral coil 2, the magnetic sheet 4b, and the magnetic resin layer 4a is the same as that of the first embodiment, and the configuration of the coil module is the configuration of FIG. It is a structure that is pulled out. Since the magnetic resin layer 4a covers the entire spiral coil 2, the thickness of the magnetic resin layer 4a is 0.8 mm.

[Example 3]
The configurations of the spiral coil 2, the magnetic sheet 4b, and the magnetic resin layer 4a are the same as those in Example 1, and the configuration of FIG. 6 is used as the configuration of the coil module. Here, the notch 21 formed in the magnetic sheet 4b had a width (direction along the edge of the notch of the magnetic sheet 4b) of 5 mm and a length (direction toward the inner diameter side of the coil module) of 10 mm. The lead portion 3a is embedded in the notch portion 21 and the magnetic resin layer 4a covers the entire spiral coil 2 excluding the lead portion 3a. Therefore, the thickness of the magnetic resin layer 4a is 0.4 mm.

[Example 4]
The configurations of the spiral coil 2, the magnetic sheet 4b, and the magnetic resin layer 4a are the same as those in Example 1, and the configuration of FIG. 7 is used as the configuration of the coil module. Here, the cutout portion 21 formed in the magnetic sheet 4b has a width of 1 mm. The thickness of the magnetic resin layer 4a is 0.4 mm as in the third embodiment.

[Comparative example]
The lead wire 1 of the spiral coil 2 is a round copper coil having an inner diameter of 35 mm, using the same round copper wire having a diameter of 0.4 mm as in the above embodiment. The number of turns is 12T. As the magnetic sheet 4b, a Mn—Zn ferrite sheet having a size of 50 mm × 50 mm and a thickness of 0.4 mm was used. The magnetic permeability of this Mn—Zn ferrite is 1000. The configuration of FIG. 11 was used as the configuration of the coil module.

[result]
The results are shown in Table 2.

  The thicknesses of the coil modules 20 and 40 of Examples 1 and 2 and the comparative example include the lead portion 3a as the thickness of the magnetic sheet layer, the thickness of the adhesive layer, and the thickness of the conductive wire 1 of the spiral coil 2. Since it consists of the thickness of two conducting wires, it is the same.

  On the other hand, in Examples 3-4, since the lead-out part 3a is accommodated in the notch 21, the thickness of one lead wire of the lead-out part 3a is 0.4 mm thinner. In addition, as above-mentioned, since it is a case of Examples 1-2, since an adhesive bond layer can be substituted for the magnetic resin layer 4a, it is with respect to a comparative example by deleting an adhesive bond layer. The thickness can be reduced.

  Regarding the inductance, Examples 1 to 4 obtained measured values equivalent to those of the comparative example, although the number of turns was 10T, which was 2T less than that of the comparative example. In Example 2, the inductance could be increased by nearly 8% compared to the comparative example. This is because the magnetic flux focusing action is improved because the magnetic resin layer 4a is added in addition to the magnetic sheet 4b. The reason why the inductances of Examples 3 to 4 are about 5% smaller than that of the comparative example is that the amount of the magnetic sheet 4b is reduced by providing the notch portion 21.

  Regarding the direct current resistance, Examples 1 to 4 obtained lower values than the comparative example because the number of turns was 2T less. As a result, the Joule heat (copper loss) is reduced and the temperature rise of the coil modules 20 and 40 is as follows. Examples 1-4 are 3.2 ° C. (Example 4) to 4.2 ° C. (Examples). 2) It became low. In particular, in Example 2, the temperature increase of the coil modules 20 and 40 was most suppressed because the amount of the magnetic resin layer 4a made of silicone resin and amorphous magnetic particles was larger than that in the other examples, so that the antenna performance This is because improvement of heat conduction contributes.

  Thus, in the coil module 20 of the present invention, the number of turns can be reduced to obtain an inductance equivalent to that of the conventional coil module 40, so that the DC resistance can be reduced. For this reason, heat generation of the coil module can be suppressed, and downsizing is also possible. Further, in the coil module of the present invention, the heat radiation performance is improved by the magnetic resin layer, so that transmission with higher power is possible, and the space for heat radiation inside the mounted electronic device can be reduced. , Enabling further miniaturization.

  DESCRIPTION OF SYMBOLS 1 Conductor, 2 Spiral coil, 3a, 3b Lead part, 4 Magnetic shield layer, 4a Magnetic resin layer, 4b, 5, 42 Magnetic sheet 10, 20, 40, 50 Coil module, 21 Notch part, 30 Power transmission coil, 31 Al thin plate, 32 Primary switching circuit, 33 AC power supply, 34 Rectifier smoothing circuit, 35 Constant power load device, 36 Thermocouple thermometer, 41 Adhesive layer

The present invention relates to a coil module including a spiral coil and a magnetic shield layer made of a magnetic shield material, and more particularly to a coil module having a magnetic resin layer containing magnetic particles as a magnetic shield layer and a power receiving device using the coil module .

As means for solving the above-described problems, a coil module according to the present invention includes a magnetic shield layer containing a magnetic material and a spiral coil. The magnetic shield layer has a magnetic resin layer containing magnetic particles, and at least a part of the spiral coil is embedded in the magnetic resin layer. The power receiving device according to the present invention includes a coil module having a magnetic shield layer containing a magnetic material and a spiral coil, and a rectifier circuit for rectifying the power receiving input of the coil module, and the magnetic shield layer contains magnetic particles. The spiral coil has at least a portion embedded in the magnetic resin layer.

According to the coil module and the power receiving device according to the present invention, since at least a part of the magnetic shield layer has the magnetic resin layer embedded in the magnetic resin layer, the heat dissipation effect by the magnetic resin layer is obtained and the small size is obtained. Can be made thinner and thinner.

Claims (10)

A magnetic shield layer containing a magnetic material;
A spiral coil,
The magnetic shield layer has a magnetic resin layer containing magnetic particles,
A coil module, wherein at least a part of the spiral coil is embedded in the magnetic resin layer.   The coil module according to claim 1, wherein the spiral coil is embedded so that an inner diameter portion of the spiral coil is filled with the magnetic resin layer.   The coil module according to claim 1, wherein the spiral coil is entirely embedded in the magnetic resin layer.   The coil module according to claim 1, wherein the magnetic shield layer includes at least two kinds of magnetic materials. The two or more kinds of magnetic materials include the kind of shape of the magnetic particles,
5. The coil module according to claim 4, wherein one or more kinds of shapes of the magnetic particles are selected from spherical powder, crushed powder, and flat powder.   The coil module according to claim 4, wherein the two or more types of magnetic materials include at least two types of magnetic materials having different magnetic permeability. The magnetic shield layer has the magnetic resin layer and a magnetic sheet in which a magnetic material is formed in a sheet shape,
The coil module according to claim 6, wherein the magnetic resin layer is laminated on the magnetic sheet. The magnetic shield layer has the magnetic resin layer and a magnetic sheet in which a magnetic material is formed in a sheet shape,
7. The coil module according to claim 6, wherein the spiral coil is embedded in the magnetic resin layer, and the magnetic resin layer and the magnetic sheet are connected by an adhesive layer.   9. The coil module according to claim 7, wherein the magnetic sheet has a cutout portion that accommodates a terminal of the spiral coil that protrudes in a thickness direction of the coil module.   The coil module according to any one of claims 4 to 9, further comprising a protective sheet made of an insulating resin laminated on a surface of the magnetic sheet.

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