TW201409500A - Coil module and power receiver - Google Patents

Abstract

The purpose of the present invention is to provide a coil module that minimizes the generation of heat in an antenna coil, and can be made smaller and thinner. The coil module (10) is provided with a spiral coil (2) formed by winding conducting wires (1) in a spiral shape, and a magnetic resin layer (4a) comprising a resin containing magnetic particles. The spiral coil (2) has pull-out sections (3a, 3b) at the ends of the conducting wires (1), and a secondary-side circuit of a non-contact charging circuit is configured by connecting a rectifier circuit or the like to the pull-out sections (3a, 3b). The magnetic resin layer (4a) is preferably formed by embedding the entire spiral coil (2).

Description

Coil module and power receiving device

The present invention relates to a coil module including a spiral coil and a magnetic shield layer composed of a magnetic shield material, and a power receiving device including the coil module, and more particularly to a coil mold having a magnetic resin layer containing magnetic particles as a magnetic shield layer. A group and a power receiving device having the coil module. The present application claims priority on the basis of Japanese Patent Application No. 2012-165825, filed on Jan.

In recent years, wireless communication devices include a telecom antenna, a GPS antenna, a wireless LAN/BLUETOOTH (registered trademark) antenna, and a plurality of RF antennas called RFID (Radio Frequency Identification). In addition to these, with the introduction of non-contact charging, the antenna coil for power transmission has also been mounted. Examples of the power transmission method using the non-contact charging method include an electromagnetic induction method, a radio wave reception method, and a magnetic resonance method. These are all electromagnetic induction or magnetic resonance between the primary side coil and the secondary side coil, and the above RFID also utilizes electromagnetic induction.

These antennas, even if designed to achieve maximum characteristics at a target frequency at a single antenna, can be difficult to obtain the target characteristics if actually constructed in an electronic machine. The reason is that the magnetic field component around the antenna interferes (couples) with the metal located at the periphery because the antenna line The inductance of the loop is substantially reduced and the resonant frequency will shift. Also, since the inductance is substantially reduced, the receiving sensitivity is also lowered. As a countermeasure against these, by inserting a magnetic shield between the antenna coil and the metal existing around the antenna, the magnetic flux generated from the antenna coil is concentrated on the magnetic shield, whereby the state of metal interference can be reduced.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2008-210861

In addition to the above-mentioned general problem of the antenna, in the electromagnetic induction type non-contact charging, it is necessary to suppress the heat generation of the antenna coil and at the same time to improve the transmission efficiency of the transmission power from the primary side to the secondary side. In addition, when it is considered to be mounted on an electronic device such as a mobile terminal device, it is most important to achieve miniaturization and thinning of the antenna coil. For example, in Patent Document 1, as shown in FIG. 12, it is described that a magnetic flux for collecting magnetic flux (herein, a magnetic sheet 4b as an explanation) is adhered to a spiral coil-shaped ring through an adhesive layer 41 coated with an adhesive. The coil module 50 of the antenna element 2 is constructed. Further, in order to reduce the thickness of the coil module for electromagnetic induction type non-contact charging, a notch 21 is formed by forming a sheet-like magnetic sheet 4b by ferrite iron or the like, and the lead portion 3a of the coil 1 is pulled. The technique of accommodating the notch portion 21 is also described.

However, in the conventional coil module including the spiral coil used as the antenna coil and the magnetic shield member disposed adjacent thereto, in order to make the coil module more compact and thinner, only the coil winding is thinned or A method of thinning a magnetic shield material. If the coil winding becomes thinner, the resistance of the wire (mainly using Cu) rises and the coil temperature rises. When the temperature of the casing of the electronic device rises due to the heat generation of the coil, it must be used for the space for cooling, which causes obstruction and miniaturization. Moreover, if the magnetic shield material becomes small and thin, the magnetic shielding effect is reduced, and the gold around the antenna coil Genus (such as a battery pack), due to the generation of eddy currents, will cause a problem of reduced transmission efficiency.

Moreover, in the conventional coil module, in the process, since the spiral coil is fixed on the magnetic sheet by using the adhesive, the process is troublesome, and the thickness of the layer coated with the adhesive also increases the thickness of the coil module. presence. Further, in the conventional coil module, a magnetic sheet is formed by fragile ferrite, and in order to prevent damage due to an external force, a protective sheet made of an insulating material is adhered to the surface of the magnetic sheet. Therefore, it is necessary to have a protective sheet attaching step, and there is a problem that the thickness of the coil module increases in accordance with the thickness of the protective sheet.

Therefore, the present invention has an object of providing a coil module that suppresses heat generation of an antenna coil and that is small and thin, and a power receiving device including the coil module.

As a means for solving the above problems, the coil module of the present invention includes a magnetic shield layer containing a magnetic material and a spiral coil. Further, 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. Further, the power receiving device of the present invention includes a coil module including a magnetic shield layer and a spiral coil of a magnetic material, and a rectifier circuit for rectifying a power receiving input of the coil module, wherein the magnetic shield layer has a magnetic resin containing magnetic particles. In the layer, at least a part of the spiral coil is embedded in the magnetic resin layer.

In the coil module of the present invention and the power receiving device including the coil module, since at least a part of the magnetic shield layer is embedded in the magnetic resin layer of the magnetic resin layer, the heat dissipation effect of the magnetic resin layer can be obtained, and the size and thickness can be reduced. It also becomes possible.

1‧‧‧ wire

2‧‧‧ spiral coil

3a, 3b‧‧‧ pull out

4‧‧‧Magnetic shielding

4a‧‧‧Magnetic resin layer

4b, 5, 42‧‧‧ magnetic sheets

10,20,40,50‧‧‧ coil module

21‧‧‧Gap section

30‧‧‧Power coil

31‧‧‧Al sheet

32‧‧‧primary side switching circuit

33‧‧‧AC power supply

34‧‧‧Rectifying and smoothing circuit

35‧‧‧Constant power load device

36‧‧‧ Thermocouple thermometer

41‧‧‧ adhesive layer

Fig. 1(A) is a plan view of a coil module according to a first embodiment of the present invention. figure 1 (B) is a cross-sectional view taken along line AA' of Fig. 1(A).

Fig. 2(A) is a perspective view showing the appearance of a model of the analog coil module constructed to evaluate the characteristics of the coil module to which the present invention is applied. Fig. 2(B) is a perspective view showing the appearance of a model of the analog coil module which is constructed in comparison with the characteristics of the coil module of the present invention.

Fig. 3(A) is a plan view showing a modification of the coil module according to the first embodiment of the present invention. Fig. 3(B) is a cross-sectional view taken along line AA' of Fig. 3(A).

Fig. 4(A) is a plan view of a coil module to which the second embodiment of the present invention is applied. Fig. 4(B) is a cross-sectional view taken along line AA' of Fig. 4(A).

Fig. 5(A) is a plan view showing a modification of the coil module to which the second embodiment of the present invention is applied. Fig. 5(B) is a cross-sectional view taken along line AA' of Fig. 5(A).

Fig. 6(A) is a plan view showing a modification of the coil module to which the second embodiment of the present invention is applied. Fig. 6(B) is a cross-sectional view taken along line AA' of Fig. 6(A).

Fig. 7(A) is a plan view showing a modification of the coil module to which the second embodiment of the present invention is applied. Fig. 7(B) is a cross-sectional view taken along line AA' of Fig. 8(A).

Fig. 8(A) is a plan view showing a modification of the coil module to which the second embodiment of the present invention is applied. Fig. 8(B) is a cross-sectional view taken along line AA' of Fig. 8(A).

Fig. 9(A) is a plan view showing a modification of the coil module to which the second embodiment of the present invention is applied. Fig. 9(B) is a cross-sectional view taken along line AA' of Fig. 9(A).

Figure 10 is a block diagram of a measurement circuit constructed to compare the characteristics of the coil module and the conventional coil module of the present invention.

Figure 11 (A) is a plan view of a conventional coil module. Figure 11 (B) is a cross-sectional view taken along line AA' of Figure 11 (A).

Fig. 12(A) is a plan view showing a conventional coil module of Patent Document 1. Fig. 12 (B) is a cross-sectional view taken along line AA' of Fig. 12 (A).

Hereinafter, the form for carrying out the invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below, and various modifications are possible without departing from the scope of the invention.

(First embodiment)

(Composition of coil module)

As shown in Fig. 1 (A) and Fig. 1 (B), the coil module 10 is a magnetic resin layer 4a including a spiral coil 2 formed by spirally winding a wire 1 and a resin containing magnetic particles. The spiral coil 2 has pull-out portions 3a and 3b at the end portion of the lead wire 1, and a rectifying circuit or the like is connected to the pull-out portions 3a and 3b to constitute a secondary side circuit of the non-contact charging circuit. As shown in Fig. 1(B), the pull-out portion 3a on the inner diameter side of the spiral coil 2 is pulled out to the outer diameter side of the spiral coil 2 so as to intersect the lead wire 1 through the lower side of the wound lead wire 1. The magnetic resin layer 4a is preferably formed by embedding the entirety of the spiral coil 2. Here, the thickness of the magnetic resin layer 4a can be the thickness of the wire 1 and the thickness of the coil module 10 can be the thickness of the wire 1 × 2 because the thickness of the wire 1 can be less than or equal to 2.

The magnetic resin layer 4a is a resin containing magnetic particles composed of soft magnetic powder and a binder. The magnetic particles are oxide magnetic materials such as ferrite iron, Fe-based, Co-based, Ni-based, Fe-Ni-based, Fe-Co-based, Fe-Al-based, Fe-Si-based, Fe-Si-Al-based, Fe-based a crystal system such as a Ni-Si-Al system, a microcrystalline metal magnetic body, or a Fe-Si-B system, a Fe-Si-BC system, a Co-Si-B system, a Co-Zr system, or a Co-Nb. A particle of an amorphous metal magnetic body such as a Co-Ta system. Magnetic particle Although a spherical or flat powder having a particle diameter of several μm to several 10 μm is used, the crushed powder may be mixed. In the case of the above-described metal magnetic body, the complex magnetic permeability has a frequency characteristic, and when the operating frequency is increased, the surface effect is lost, so that the particle diameter and shape are adjusted depending on the use frequency band. Further, the inductance value of the coil module 10 is determined based on the real magnetic permeability of the magnetic body (hereinafter, simply referred to as magnetic permeability), but the magnetic permeability can be adjusted according to the mixing ratio of the magnetic particles and the resin. . The relationship between the average magnetic permeability of the magnetic resin layer 4a and the magnetic permeability of the magnetic particles to be blended is generally assuming a volumetric filling ratio in which the interaction between the particles is increased in accordance with the logarithmic mixing rule. 40 vol% or more. Further, the heat conduction property of the magnetic resin layer 4a also increases as the filling rate of the magnetic particles increases.

The magnetic resin layer 4a is not limited to a case where it is composed of only a single magnetic material. Two or more kinds of magnetic materials may be used in combination, and a plurality of layers may be laminated to form a magnetic resin layer. Even in the same magnetic material, the particle diameter and/or shape of a plurality of types of magnetic particles may be selected and mixed, and a plurality of layers may be laminated. Because of these changing possibilities, the desired magnetic properties can be achieved.

As the binder, a resin which is hardened by heat or ultraviolet rays or the like is used. As the binder, for example, a resin such as an epoxy resin, a phenol resin, a melamine resin, a urea resin, or an unsaturated polyester, or a silicone rubber, a urethane rubber, an acrylate rubber, a butyl rubber, or an ethylene propylene rubber can be used. Material. Needless to say, it is not limited to this. Further, a flame retardant, a reaction adjusting material, a crosslinking agent or a decane coupling agent may be appropriately added to the above resin or rubber.

The lead wire 1 forming the spiral coil 2 is preferably a single wire composed of an alloy containing Cu or Cu as a main component having a diameter of 0.20 mm to 0.45 mm when a frequency of about 120 kHz is used in the case of charging the output capacitor 5 W. Or, in order to reduce the surface effect of the wire 1, it is also possible to use a plurality of parallel lines and braided wires which are thinner than the thin wires of the single wire described above, and may also be used. A thin flat line or a flat line is used as a 1-layer or 2-layer alpha roll.

(Manufacturing method of coil module)

In the magnetic resin layer 4a, the spiral coil 2 is placed on the mold frame of the final shape of the coil module 10, and the magnetic particles such as the ferrite iron and the like are mixed with the resin or rubber of the adhesive to be injected into the mold frame to be molded. Then, the resin or the like is hardened by heating or ultraviolet irradiation to form the coil module 10. Alternatively, a predetermined amount of resin or the like is injected into the mold frame of the coil module 10, and the resin or the like in a soft state before curing is embedded in the spiral coil 2, and then the resin or the like is hardened by heating or ultraviolet irradiation to form a coil mold. Group 10.

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

The amount of the resin may be such that the spiral coil 2 is entirely buried as shown in Fig. 1, or the wire 1 and the drawn portion 3a may be partially exposed. Further, the position of the resin or the like may be a position of the lower side of the filling wire 1 and a position of the outer portion of the spiral coil 2. As will be described later, the area of the lower side of the filling wire 1 and the inner diameter portion of the spiral coil 2 may be used. Also.

According to this manufacturing method, in the case where the spiral coil 2 and the magnetic resin layer 4a are fixed, it is not necessary to use an adhesive. Therefore, the application step of the adhesive can be reduced, and the coil module 10 can be made thinner in accordance with the adhesive layer which is not formed by the application of the adhesive. Further, in the magnetic resin layer 4a, since the resin is mixed as described above, damage to the external impact is not caused, and it is not necessary to adhere the protective sheet to the surface. Therefore, the protective sheet bonding step can be reduced, and the thickness of the coil module which is increased by the protective sheet can be suppressed.

(Compared with the characteristics of the conventional coil module)

The characteristics of the coil module 10 of the present invention were evaluated using a simulation program. Fig. 2 is a perspective view showing the shape of a coil module for analysis.

As shown in Fig. 2(A), in the coil module 10 of the present invention, the spiral coil 2 in which the wound wire 1 is wound in a circular shape is entirely embedded in the magnetic resin layer 4a. The wire 1 of the spiral coil 2 is a rectangular wire having a line width of 1 mm × a wire thickness of 0.2 mm. This wire 1 is wound 3 turns to constitute the spiral coil 2. The magnetic resin layer 4a is composed of a size of 43 mm × 43 mm × 0.75 mm. As described above, the electrical characteristics of the magnetic permeability and the like of the magnetic resin layer 4a can be changed by the mixing ratio of the material of the magnetic example, the particle shape, the particle diameter, and the resin (or rubber), and the magnetic resin layer 4a. The magnetic permeability is simulated for four types of 15, 20, 25, and 30.

As shown in FIG. 2(B), the conventional coil module 40 is formed of a spiral coil 2 having the same thickness as that of FIG. 2(A) through a 0.15 mm thick adhesive layer formed of Ni-Zn having a magnetic permeability of 100. Above the magnetic sheet 5 composed of ferrite iron. The magnetic sheet 5 has a size of 43 mm × 43 mm × 0.4 mm, and is configured such that a notch portion 21 is provided in a portion where the pull-out portion 3a from the inner diameter side of the spiral coil 2 overlaps the lead wire 1 to accommodate the pull-out portion 3a. Since the thickness of the magnetic sheet 5 is 0.4 mm, the thickness of the adhesive layer is 0.15 mm, the thickness of the wire is 0.2 mm, and the thickness of the entire coil module is 0.75 mm, which is the same as the coil module of Fig. 2(A).

In the case of any of FIG. 2(A) and FIG. 2(B), it is assumed that the coil module is mounted in the electronic device, and is disposed from the side of the spiral coil of the magnetic resin layer 4a and the magnetic sheet 5 of the respective coils. An Al thin plate of 40 mm × 40 mm × 0.3 mm was disposed oppositely to the side surface by 0.1 mm.

As described above, regarding the coil modules of the same outer dimensions, Table 1 shows the results of calculating the inductance and Q by simulation. In addition, Table 1 shows the numerical values normalized on the basis of the comparative example.

As shown in Table 1, it can be understood that the coil module 10 of the present invention has the same characteristics as the conventional coil module 40 having the magnetic sheet having the magnetic permeability of 100, and the magnetic permeability is 30 or more. . Regarding Q, even if the magnetic permeability is 15, it is equivalent to the characteristics of the conventional coil module 40.

Therefore, the coil module 10 of the present invention having a thickness equal to that of the conventional coil module 40 can achieve the characteristics of the conventional coil module 40 by adjusting the appropriate ratio of the magnetic permeability by adjusting the mixing ratio of the magnetic particles or the like.

As described above, in the case where the coil module 10 of the present invention has the same thickness and the same inductance as the conventional coil module 40, a coil of a higher Q can be realized. The high Q value, in the case of coupling with the primary side coil, can be expected to improve the transmission efficiency.

In addition, since the structure of the spiral coil 2 is embedded in the magnetic resin layer 4a, the Joule heat generated in the wire 1 can be very effectively performed by the high heat conduction property of the magnetic resin layer 4a containing a plurality of thermally conductive high magnetic bodies. Cooling. With the high-efficiency heat-dissipating structure, the coil module 10 of the present invention can be constructed in a narrower configuration space in the case of an electronic device, and can appropriately meet the demand for miniaturization and thinning of the electronic device.

In the conventional coil module 40, as shown in Figs. 11(A) and 11(B), the pull-out portion 3a on the inner diameter side of the spiral coil 2 from the wire 1 is pulled over the other wires 1 In the structure, the thickness of the coil module is increased in accordance with the thickness of the pull-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 adhesive layer 41 also thickens the thickness of the coil module. Further, in the case of the coil module 50 described in Patent Document 1, as shown in FIG. 12, the adhesive layer 41a is partially housed in the notch portion 21 provided in the magnetic piece 4b without an excessive thickness, and the adhesive layer 41 is provided. It also increases the thickness. In the case of the coil module 10 of the present invention, in the case of the configuration of the first and third embodiments, the magnetic resin layer 4a can fix the spiral coil 2, and the adhesive layer 41 is not required, contributing to the reduction in thickness.

(Modification of the first embodiment)

In the first embodiment of the present invention, even if the entire spiral coil 2 is not embedded in the magnetic resin layer 4a of the coil module 10, the magnetic resin layer 4a is formed on the magnetic circuit of the spiral coil 2, and the performance such as inductance improvement can be achieved. Upgrade.

As shown in FIG. 3(A) and FIG. 3(B), the coil module 10 of the present invention includes a spiral coil 2 formed by spirally winding a wire 1, and a magnetic material composed of a resin containing magnetic particles. The resin layer 4a and the magnetic resin layer 4a are formed such that the drawing portion 3a is buried in the surface of the inner diameter portion 11 of the spiral coil 2 and the spiral coil 2. The spiral coil 2 has pull-out portions 3a and 3b at the end portion of the lead wire 1, and a rectifying circuit or the like is connected to the pull-out portions 3a and 3b to constitute a secondary side circuit of the non-contact charging circuit. As shown in Fig. 3(B), the pull-out portion 3a of the inner portion of the spiral coil 2 is pulled out to the outer diameter side of the spiral coil 2 by the lower side of the wound lead 1, as in the case of Fig. 1 described above. .

Therefore, the magnetic resin layer 4a is disposed in a spiral with an arbitrary amount of embedding When the coil 2 contacts and communicates, the opposite side of the opposing surface and the position around the spiral coil 2 are adjusted, and the material ratio of the magnetic particles, the mixing ratio of the magnetic particles and the resin (or rubber), and the shape of the magnetic particles are adjusted. The coil module 10 having a desired characteristic and shape can be formed by the characteristics of the magnetic material such as the magnetic permeability set by the particle diameter or the like. With this degree of freedom, the space in the small electronic machine can be effectively utilized, and the contribution of weight reduction can also be achieved. Further, even in a smaller amount of the magnetic resin layer 4a, electrical characteristics equivalent to those of the conventional coil module can be achieved, and since one of the wires 1 is buried in the magnetic resin layer 4a, a high heat dissipation effect can be expected.

(Second embodiment)

(Composition of coil module)

The coil module of the present invention can be constituted by using a plurality of magnetic shielding layers of two or more types of magnetic materials. In particular, by combining with a magnetic sheet having high magnetic permeability, electrical characteristics can be improved, and further compactness and thickness can be achieved.

As shown in FIG. 4(A) and FIG. 4(B), the coil module 20 of the present invention is provided with a magnetic material 4b formed of a magnetic material having high magnetic permeability, for example, Ni-Zn ferrite, and placed thereon. The spiral coil 2 on the magnetic sheet 4b and the magnetic resin layer 4a formed to embed the spiral coil 2 are provided. The magnetic shield layer 4 is a laminate of the magnetic sheet 4b and the magnetic resin layer 4a. The spiral coil 2 is pulled out in such a manner that the pull-out portion 3a from the inner diameter side of the spiral coil 2 crosses over the other wires 1. The magnetic resin layer 4a is entirely embedded in the spiral coil 2 other than the intersection of the drawn portions 3a. Further, although not shown, when the magnetic sheet 4b is formed using an easily crushable material such as ferrite iron, the protective sheet may be adhered to the surface on the opposite side to the surface on which the spiral coil 2 is placed on the magnetic sheet 4b.

The magnetic resin layer 4a contains magnetic particles composed of soft magnetic powder and a resin as a binder, and is the same as in the first embodiment. That is, an oxide magnetic body such as ferrite iron, It means a crystal system of Fe, Co, Ni, Fe-Ni, Fe-Co, Fe-Al, Fe-Si, Fe-Si-Al, Fe-Ni-Si-Al, etc. , a microcrystalline metal magnetic body, or an amorphous metal such as Fe-Si-B system, Fe-Si-BC system, Co-Si-B system, Co-Zr system, Co-Nb system or Co-Ta system. Particles of magnetic particles. Although the magnetic particles are spherical or flat powder having a particle diameter of several μm to several 10 μm, the crushed powder may be mixed. In the case of the above-described metal magnetic body, if the frequency is increased by the frequency dependence of the complex magnetic permeability, the surface effect is lost. Therefore, the particle diameter and shape are adjusted in accordance with the band of the used frequency.

The adhesive for the magnetic resin layer 4a is the same as that of the first embodiment. That is, a resin which is hardened by heat, ultraviolet irradiation or the like is used. As the binder, for example, an epoxy resin, a phenol resin, a melamine resin, a urea resin, a resin such as an unsaturated polyester, a silicone rubber, a urethane rubber, an acrylate rubber, a butyl rubber, an ethylene propylene rubber, or the like can be used. Materials, needless to say, are not limited to this.

In the magnetic sheet 4b, generally, a ferrite iron having a high electrical resistivity is used, and a magnetic material similar to the magnetic particles, for example, an amorphous metal magnetic body such as Fe-based or Co-based, or iron may be used. A Fe-based crystalline metal magnetic body such as yttrium aluminum or a high magnetic permeability alloy, or a microcrystalline magnetic body.

(Method of Manufacturing the Coil Module of the Second Embodiment)

Next, an example of a method of manufacturing the coil module 10 according to the second embodiment of the present invention will be described. First, the magnetic sheets 4b and 14b are prepared, and the magnetic sheets 4b and 14b are used as the ferrite iron as an example.

The mixture of the ferrite-grained iron raw materials is pressed into a mold frame to be fired into a block-shaped ferrite iron, which is then formed into a sheet by cutting.

The magnetic sheet 4b thus formed is further disposed in the mold frame, in the magnetic sheet 4b After the spiral coil 2 is placed, a magnetic resin is injected into the mold frame. Although the adhesive agent may be applied to the magnetic sheet 4b in order to fix the spiral coil 2 when it is placed on the magnetic sheet 4b, it is preferable to fix the spiral coil 2 by using a magnetic resin before curing instead of the adhesive. Thereafter, the magnetic resin is cured by heating or ultraviolet irradiation to extract the coil module 20 from the mold frame. In the same manner as in the first embodiment, the spiral coil 2 may be embedded after the magnetic resin is injected.

Alternatively, the magnetic resin is injected into the mold frame, but the spiral coil 2 is embedded, and the magnetic resin layer 4a is placed on the sintered magnetic sheet 4b so as to be coated, and then the magnetic resin may be cured.

In the case where the magnetic sheet 4b is formed, other methods can be used without using the cutting method. For example, a ferrite iron slurry prepared by using a mixed ferrite iron raw material powder and a binder is formed into a sheet shape (green sheet) by a doctor blade method or the like, and then a green sheet formed into a predetermined shape by a hollow mold or the like is fired. The method of forming a ferrite piece can also be used. The coil module of the present invention can be formed on the sintered magnetic piece 4b of the ferrite iron by applying the same processing as described above.

Further, the notch portion 21 may be formed in the magnetic sheet 4b as will be described later. In this case, after the block-shaped fat iron is sintered, the notch portion 21 may be formed in a block state, or the notch portion 21 may be formed by groove processing after the magnetic sheet 4b is cut. Moreover, in the case where the magnetic sheet 4b is formed from the green sheet, the magnetic sheet 4b in which the notch portion 21 is formed can be formed by preparing the empty mold in which the notch portion 21 is considered in advance.

(Modification of Second Embodiment)

5(A) and 5(B) are diagrams showing a modification of the case where the pull-out portion 3a of the inner diameter of the spiral coil 2 is pulled out from the lower portion of the other lead wire 1, that is, from the side of the magnetic sheet 4b. . In this modification, the magnetic resin layer 4a is embedded in the magnetic resin layer 4a by the drawing portion 3a and the spiral coil 2, The thickness is thicker than in the case of FIG. Since the magnetic resin layer 4a is thicker, the inductance is increased, and the electrical characteristics of the coil are improved. Further, even in the case of Fig. 4, it is needless to say that the thickness of the magnetic resin layer 4a can be the thickness of two of the wires 1.

6(A) and 6(B) show the case where the pull-out portion 3a from the inner diameter of the spiral coil 2 is pulled out from the side of the other wire 1, that is, from the side of the magnetic piece 4b, by the magnetic piece. 4b corresponds to a modification of the portion in which the notch portion 21 is formed in the portion corresponding to the drawing portion 3a and is thinned. Since the drawing portion 3a is buried in the notch portion 21, the thickness of the coil module 20 can be made thinner depending on the thickness of the wire 1 or the thickness of the magnetic piece 4b.

7(A) and 7(B) show the case where the notch portion 21 is formed in the portion of the magnetic piece 4b corresponding to the drawing portion 3a, and is not limited to the portion corresponding to the drawing portion 3a, and is in the entire length of the magnetic piece 4b. An illustration of a modification in which the upper notch portion 21 is extended.

In any of FIGS. 6 and 7, the magnetic resin is filled in the notch portion 21, but it is needless to say that the magnetic resin is not filled in the notch portion 21.

As shown in FIGS. 8(A) and 8(B), the magnetic resin layer 4a may be formed without embedding the entire spiral coil 2, or may be formed by filling the inner diameter portion 11 of the spiral coil 2.

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

(Example)

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 fabricated, and the respective electrical characteristics are evaluated. Further, the coil modules 20 and 40 are respectively mounted on the non-contact charging circuit, and the evaluation coil module is mounted. The temperature of 20 and 40 rises.

An evaluation circuit for evaluating the temperature rise of the coil modules 20, 40 is shown in FIG. The evaluation circuit includes a primary side switching circuit 32 to which an AC power source 33 is connected, a power transmitting coil 30 driven by driving the primary side switching circuit, and a coil module 20 and 40 as a secondary side power receiving coil to make the coil module 20, 40 switching waveform rectification smoothing rectification smoothing circuit 34, constant power load device 35. The power transmitting coil 30 and the coil module 20 are arranged in opposite directions and are fixed at intervals of 2.5 mm. On the side opposite to the side opposite to the power transmitting coil 30 of the coil modules 20 and 40, an Al thin plate having a thickness of 0.3 mm and substantially the same area as that of the coil modules 20 and 40 is placed. In order to measure the temperatures of the coil modules 20, 40, the thermocouples are adhered to the surfaces of the coil modules 20, 40, and the temperature is measured by the thermocouple thermometer 36. Further, in the case where the coil modules 20 and 40 are mounted on an actual electronic device, the Al thin plate 31 is a battery exterior case made of a simulated metal.

(Example 1)

In the configuration of the coil module, a magnetic sheet 4b, a spiral coil 2 placed on the magnetic sheet 4b, and a magnetic resin layer 4a formed by embedding the entire spiral coil 2 are provided. The pull-out portion 3a is pulled out from the inner side of the spiral coil 2 on the upper side of the wire 1. In the magnetic resin layer 4a, the entire thickness of the spiral coil 2 other than the intersection of the drawn portion 3a is covered, and the thickness of the magnetic resin layer 4a is 0.4 mm. Further, the magnetic sheet 4b and the spiral coil 2 were fixed by an adhesive layer in the same manner as the comparative example described later (in the comparative experiment, the total thickness of the coil module was not included because the adhesive layer was extremely thin by 10 μm). The wire 1 of the spiral coil 2 was made of a round wire (one type) of Cu having a diameter of 0.4 mm as a circular spiral coil having an inner diameter of 35 mm. The number of turns is 10T. For the magnetic sheet 4b, a Mn-Zn fat iron 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 tablet was 1000. In the magnetic resin layer 4a, a spherical amorphous material (D50 = 10 μm) containing 65% Fe is used for the silicone resin.

(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. As a configuration of the coil module, the configuration of Fig. 5 is such that the pull-out portion 3a is pulled from the lower side of the wire 1. Out. The magnetic resin layer 4a is coated with the entire spiral coil 2, and the thickness of the magnetic resin layer 4a is 0.8 mm.

(Example 3)

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 as shown in Fig. 6. Here, the notch portion 21 formed on the magnetic sheet 4b has a width (in the direction of the edge of the notch portion of the magnetic piece 4b) of 5 mm and a length (direction toward the inner diameter side of the coil module) of 10 mm. The pull-out portion 3a is embedded in the cutout portion 21, and the magnetic resin layer 4a covers the entire spiral coil 2 except for the pull-out portion 3a, and the thickness of the magnetic resin layer 4a is 0.4 mm.

(Example 4)

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 as shown in Fig. 7. Here, the notch portion 21 formed on the magnetic sheet 4b has a width of 1 mm. The thickness of the magnetic resin layer 4a was 0.4 mm as in the case of Example 3.

(Comparative example)

The wire 1 of the spiral coil 2 was a round wire of Cu having a diameter of 0.4 mm as in the above-described embodiment, and was used as a circular spiral coil having an inner diameter of 35 mm. The number of turns is 12T. For the magnetic sheet 4b, a Mn-Zn fat iron 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 tablet was 1000. The configuration of the coil module is as shown in Fig. 11.

(result)

The results are disclosed in Table 2.

The thicknesses of the coil modules 20 and 40 of the first to second and comparative examples are the thickness of the magnetic sheet layer, the thickness of the adhesive, and the thickness of the wire 1 of the spiral coil 2, and the two wires including the pull-out portion 3a. The thickness is composed and therefore the same.

On the other hand, in the third to fourth embodiments, since the cutout portion 3a is accommodated in the notch portion 21, the thickness of one of the wires of the drawing portion 3a is reduced to 0.4 mm. Further, as described above, even in Examples 1 and 2, since the magnetic resin layer 4a can be used instead of the adhesive layer, the thickness of the adhesive layer can be made thinner by the removal of the adhesive layer.

Regarding the inductance, in Examples 1 to 4, the number of turns was 2T as 10T as compared with the comparative example, but the same measurement value as in the comparative example was obtained. In Example 2, the inductance was increased by nearly 8% compared to the comparative example. Here, in addition to the magnetic sheet 4b, the magnetic flux effect is increased by the additional magnetic resin layer 4a. Further, the reason why the inductance of Examples 3 to 4 is about 5% smaller than that of the comparative example is that the amount of the magnetic sheet 4b can be reduced by providing the notch portion 21.

Regarding the DC resistance, in Examples 1 to 4, a lower value of 2T was obtained as compared with the comparative example. Thereby, reducing the Joule heat (copper loss) causes the temperature of the coil modules 20 and 40 to rise. The results of Examples 1 to 4 were reduced by 3.2 ° C compared with the comparative examples (Example 4 > 4.2 ° C (Example 2). In particular, in Example 2, the reason why the temperature rise of the coil modules 20 and 40 was most suppressed was that The amount of the magnetic resin layer 4a composed of the silicone resin and the amorphous magnetic particles is more than that of the other embodiments, contributing to an improvement in antenna performance or heat conduction.

Here, the coil module 20 of the present invention can obtain the same inductance as the conventional coil module 40, which can reduce the number of turns and reduce the DC resistance. Therefore, the heat generation of the coil module can be suppressed, and the size can be reduced. Further, in the coil module of the present invention, since the heat dissipation performance is improved by the magnetic resin layer, higher power can be transmitted, and the heat dissipation space inside the mounted electronic device can be reduced, and the size can be further reduced.

1‧‧‧ wire

2‧‧‧ spiral coil

3a, 3b‧‧‧ pull out

4a‧‧‧Magnetic resin layer

10‧‧‧ coil module

Claims (11)

A coil module comprising: a magnetic shield layer comprising a magnetic material; and a spiral coil; wherein the magnetic shield layer has a magnetic resin layer containing magnetic particles; and the spiral coil is at least partially embedded in the magnetic resin layer. The coil module according to claim 1, wherein the spiral coil is embedded such 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 of claim 1, wherein the magnetic shield layer contains at least two types of magnetic materials. The coil module of claim 4, wherein the two or more types of magnetic materials contain a type of the shape of the magnetic particles; and the shape of the magnetic particles is a spherical powder, a crushed powder, and a flat powder. Either one or more are selected. The coil module of claim 4, wherein the two or more types of magnetic materials contain at least two types of magnetic materials having different magnetic permeability. The coil module according to claim 6, wherein the magnetic shield layer has the magnetic resin layer and a magnetic sheet formed into a sheet shape with a magnetic material, and the magnetic resin layer is laminated on the magnetic sheet. The coil module of claim 6, wherein the magnetic shielding layer has The magnetic resin layer and the magnetic material formed into a sheet shape with a magnetic material; 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. The coil module according to claim 7 or 8, wherein the magnetic sheet has a notch portion of a terminal that protrudes in a thickness direction of the coil module of the spiral coil. The coil module of claim 4, further comprising a protective sheet made of an insulating resin laminated on the surface of the magnetic sheet. A power receiving device comprising: a coil module having a magnetic shield layer and a spiral coil including a magnetic material; and a rectifier circuit for rectifying a power receiving input of the coil module; the magnetic shield layer having magnetic properties containing magnetic particles a resin layer; at least a part of the spiral coil is embedded in the magnetic resin layer.