JP5336957B2 - Magnetic material, method of manufacturing magnetic material, and antenna module - Google Patents

Description

  The present invention receives a magnetic field transmitted from a transmitter, and is disposed at a position overlapping an antenna substrate on which an antenna coil that is inductively coupled to the transmitter and can communicate is mounted, and is transmitted from the transmitter. The present invention relates to a magnetic material that draws the antenna coil into the antenna coil, a manufacturing method thereof, and an antenna module incorporating the magnetic material.

  The following several types of antenna modules for RFID (Radio Frequency Identification) have been conventionally used. First, there is an antenna module in which a coil pattern is created on a plane using an FPC (Flexible Printed Circuit) or a rigid substrate. Secondly, there is an antenna module in which a coil is formed by winding a round wire. Third, there is an antenna module in which an FPC, FFC (Flexible Flat Cable) or the like is used as a harness, and the harness is formed in a ring shape to form a coil.

  The above-described antenna module is appropriately selected by a design that takes into account the arrangement and shape of components, and is used by being incorporated in an electronic device.

  When an antenna module is placed in an electronic device, it is made of ferrite with a relatively high permeability and low loss factor so as not to be affected by the metal used in the metal casing and internal parts of the electronic device. The magnetic material is attached to the antenna or its periphery (Patent Document 1).

  In this way, a magnetic material made of ferrite with good magnetic properties is placed so as to overlap the antenna module, so that the magnetic field enters the metal around the antenna module and becomes an eddy current, which generates heat. Prevent change. Moreover, the magnetic material made of ferrite has been optimized in terms of shape, combination, etc. so as to obtain good communication performance. In addition, as portable electronic devices such as cellular phones are becoming thinner, it is desired that the magnetic material made of ferrite be as thin as possible in a state of being bonded to the antenna module.

JP 2006-310812 A

  As described above, the antenna is made of a flexible electronic material such as FPC in a planar shape, and this antenna substrate is made of ferrite for the purpose of preventing the generation of eddy current and heat in the electronic device. Magnetic material may be attached. Here, the ferrite used as the magnetic material needs to be processed into the same shape as the outer peripheral shape of the antenna substrate due to size restrictions when incorporated in the device.

  Specifically, there are roughly two methods for processing ferrite used as a magnetic material. The first processing method is a method of processing and sintering in a green sheet state before sintering the ferrite. The second processing method is a method of processing after sintering the ferrite. The former has a problem in that shrinkage occurs during sintering and deviation from a specified size is likely to occur. In the latter case, the dimensions are almost as specified. However, when the processed surface 201 of the ferrite plate 200 as shown in FIG. 6A is cut by the mold 202, a chip 204 is formed on the processed surface as shown in FIG. 6B. May occur, and the problem of powder falling inside the equipment may occur.

  The present invention has been proposed in view of such circumstances, and while maintaining good magnetic properties, a magnetic material of a desired size in which the surface of the ferrite plate is protected, a method for producing the magnetic material, And it aims at providing the antenna module incorporating this magnetic material.

  In order to solve the above-described problem, the present invention is arranged at a position where an antenna coil that receives a magnetic field transmitted from a transmitter and is inductively coupled with the transmitter and capable of communicating with the antenna substrate is mounted. A magnetic material that draws a magnetic field transmitted from a transmitter into an antenna coil, which is made of a ferrite plate that is obtained by sintering a magnetic metal and processing it into a plate shape. The organic resin film is attached to the upper and lower surfaces of the ferrite plate so as to include a magnetic sheet wound on the side surface of the ferrite plate. And

  Further, the present invention is arranged at a position where an antenna coil that receives a magnetic field transmitted from the transmitter and is inductively coupled with the transmitter and capable of communicating is superimposed on the antenna substrate, and is transmitted from the transmitter. In the method of manufacturing a magnetic material that draws a magnetic field into an antenna coil, a magnetic sheet made of a magnetic alloy is wound around and adhered to the first organic resin film so as to overlap with the outer peripheral portion of the antenna coil. The ferrite plate processed into a plate shape that matches the shape of the recess formed in the organic resin film on which the magnetic sheet is wound is disposed so as to engage with the recess, The second organic resin film is pasted so as to include a magnetic sheet positioned on the side surface of the ferrite plate.

  The present invention also includes an antenna substrate on which an antenna coil that receives a magnetic field transmitted from a transmitter and is inductively coupled with the transmitter to enable communication, and a magnetic field transmitted from the transmitter is drawn into the antenna coil. The magnetic material is arranged at a position overlapping with the antenna substrate, and the magnetic material is made of a ferrite plate obtained by sintering a magnetic metal to be processed into a plate shape. The magnetic sheet is wound so as to overlap the outer periphery of the antenna coil, and the organic resin film is pasted on the upper and lower surfaces of the ferrite plate so as to include the magnetic sheet wound on the side surface of the ferrite plate. It is characterized by being worn.

  In the present invention, a magnetic sheet made of a magnetic alloy is wound on the side surface of the ferrite plate so as to overlap with the outer peripheral portion of the antenna coil. While maintaining, the side of the ferrite plate can be protected, and further, since the organic resin film is stuck on the upper and lower surfaces of the ferrite plate, the surface of the ferrite plate is protected without being exposed and desired A magnetic material of a size can be provided.

It is a figure which shows the structure of the radio | wireless communications system incorporating the antenna module to which this invention was applied. It is a figure for demonstrating the manufacturing process of the magnetic material to which this invention was applied. It is a figure for demonstrating the structure of the antenna module which concerns on an Example. It is a figure for demonstrating the structure of the antenna module which concerns on an Example. It is a figure for demonstrating the dynamic characteristic of the antenna module which concerns on an Example. It is a figure for demonstrating the workability of a ferrite plate.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention.

  An antenna module to which the present invention is applied is a device that is in a communicable state by electromagnetic induction generated with a transmitter that transmits electromagnetic waves. For example, the antenna module for RFID (Radio Frequency Identification) as shown in FIG. It is incorporated into the wireless communication system 100 and used.

  The wireless communication system 100 includes an antenna module 1 to which the present invention is applied, and a reader / writer 2 that accesses the antenna module 1.

  The reader / writer 2 functions as a transmitter that transmits a magnetic field to the antenna module 1, and specifically, an antenna 2a that transmits a magnetic field toward the antenna module 1, and an antenna that is inductively coupled via the antenna 2a. A control board 2b that communicates with the module 1 is provided.

  That is, the reader / writer 2 is provided with a control board 2b electrically connected to the antenna 2a. A control circuit composed of electronic components such as one or a plurality of integrated circuit chips is mounted on the control board 2b. The control circuit executes various processes based on the data received from the antenna module 1. For example, when writing data to the antenna module 1, the control circuit encodes the data, modulates a carrier wave of a predetermined frequency (for example, 13.56 MHz) based on the encoded data, and amplifies the modulated modulation signal Then, the antenna 2a is driven by the amplified modulation signal. Further, when reading data from the antenna module 1, the control circuit amplifies the modulation signal of the data received by the antenna 2a, demodulates the modulation signal of the amplified data, and decodes the demodulated data. In the control circuit, an encoding method and a modulation method used in a general reader / writer are used. For example, a Manchester encoding method or an ASK (Amplitude Shift Keying) modulation method is used.

  The antenna module 1 incorporated in the housing 3 of the electronic device draws a magnetic field into the antenna coil 11a and the antenna substrate 11 on which the antenna coil 11a that can communicate with the reader / writer 2 that is inductively coupled is mounted. The magnetic material 12 formed in the position which overlaps with the antenna board | substrate 11, and the communication processing part 13 which drives with the electric current which flows through the antenna coil 11a, and communicates with the reader / writer 2 are provided.

  On the antenna substrate 11, for example, an antenna coil 11a formed by mounting a flexible conductive wire such as a flexible flat cable, and a terminal portion 11b for electrically connecting the antenna coil 11a and the communication processing unit 13 Has been implemented.

  When the antenna coil 11a receives a magnetic field transmitted from the reader / writer 2, the antenna coil 11a is magnetically coupled to the reader / writer 2 by inductive coupling, receives the modulated electromagnetic wave, and communicates the received signal via the terminal portion 11b. To the unit 13.

  The magnetic material 12 is formed at a position overlapping the antenna substrate 11, and draws the magnetic field transmitted from the reader / writer 2 into the antenna coil 11a. Specifically, the magnetic material 12 has a magnetic field in order to suppress a metal part provided in the housing 3 of the portable electronic device from repelling a magnetic field transmitted from the reader / writer 2 or generating an eddy current. The structure is pasted on the opposite side of the direction from which the light is emitted.

  The communication processing unit 13 is driven by a current flowing through the antenna coil 11 a and performs communication with the reader / writer 2. Specifically, the communication processing unit 13 demodulates the received modulation signal, decodes the demodulated data, and writes the decoded data in the internal memory of the communication processing unit 13. The communication processing unit 13 reads out data to be transmitted to the reader / writer 2 from the internal memory, encodes the read data, modulates a carrier wave based on the encoded data, and is magnetically coupled by inductive coupling. The modulated radio wave is transmitted to the reader / writer 2 via the coil 11a.

  In the wireless communication system 100 configured as described above, the configuration of the magnetic material 12 will be described below with attention paid thereto.

  In the antenna module 1 according to the present embodiment, a ferrite plate obtained by sintering a magnetic metal is used as the material of the magnetic material 12 from the viewpoint of realizing good communication characteristics. The reason why the ferrite plate is used is that the magnetic field can be efficiently drawn into the antenna coil 11a because the loss factor is smaller than that of a magnetic alloy such as Fe—Si—Cr.

  There are roughly two methods for processing the shape of the ferrite plate. The first processing method is a method of processing and sintering in a green sheet state before sintering the ferrite plate. The second processing method is a method of processing a ferrite plate into a desired specified shape after sintering. The first processing method has a problem that shrinkage occurs during sintering and deviation from a specified size is likely to occur. In the second processing method, the dimensions are almost as specified, but there is a problem that chipping occurs on the processed surface and powder falling occurs inside the incorporated electronic device.

  Moreover, the magnetic material 12 needs to be processed into a specified size for the following reasons. That is, since the shape and size of the antenna module 1 are restricted when the antenna module 1 is incorporated in an electronic device, the magnetic material 12 is formed in substantially the same shape as the antenna substrate 11 and needs to be arranged so as to overlap the antenna substrate 11. Because there is.

  Thus, since the magnetic material 12 is required to be formed in substantially the same shape as the antenna substrate 11, the first processing method described above causes a change in dimensions in the sintering process. Therefore, it cannot be processed with high accuracy so as to obtain a shape to be formed.

  In the second processing method, the dimensions are almost as specified, but chipping occurs on the processed surface, and the processed surface needs to be protected. As a method of protecting the processed surface, there are a method of applying the processed surface with a liquid protective agent and a method of covering the processed surface with a solid such as an organic resin film. First, the method of thinly applying a liquid protective agent cannot be sufficiently protected when the degree of cracking of the end face is large. In addition, if a liquid protective agent is applied thickly, a dimensional problem appears. Further, in the method of attaching an organic resin film or the like to the processed surface, when the degree of crushing is large, the powder of the ferrite powder is generated from the portion where the film is not attached.

  In view of such problems, the magnetic material 12 according to the present embodiment prevents the surface of the ferrite plate from being exposed from the viewpoint of preventing the above-described powder falling from the ferrite plate while suppressing deterioration of magnetic properties. Therefore, it is manufactured as follows.

  Under such conditions, the magnetic material 12 is manufactured according to the following manufacturing process.

  As shown in the sectional view of FIG. 2A, an organic resin film 121 made of an organic resin such as polyethylene terephthalate (PET), a magnetic sheet 122 made of a magnetic alloy, and an outer peripheral portion of the magnetic sheet 122 being an antenna. While being wound so as to overlap with the outer peripheral portion 11c of the antenna coil 11a mounted on the substrate 11, it is stuck using an acrylic adhesive sheet 123 such as ADH.

  Here, the magnetic sheet 122 is configured by using a magnetic alloy such as Fe—Si—Cr, Fe—Si—Al, Fe—Ni, and amorphous. In particular, the magnetic sheet 122 is made of a magnetic alloy such as Fe-Si-Cr or Fe-Si-Al containing silicon, and the magnetic alloy is a flat magnetic powder and is dispersed and mixed in an organic resin. . Depending on the type of organic resin, it is possible to impart plasticity to the magnetic sheet. Therefore, by using the magnetic sheet 122 made of a magnetic alloy such as Fe-Si-Cr-based or Fe-Si-Al containing silicon, the outer peripheral portion 11c of the antenna coil 11a mounted on the antenna substrate 11 is overlapped. Winding becomes easy, and it is suitable for performing this manufacturing process.

  In addition, it is desirable from the viewpoint of improving communication characteristics that the width of the magnetic sheet 122, that is, the length in the surface direction, be as small as possible to increase the width of the ferrite plate 124 described later.

  Further, from the viewpoint of reducing the thickness of the magnetic material 12, the organic resin film 121 and the acrylic adhesive sheet 123 are preferably as thin as possible. The magnetic sheet 122 preferably has a film thickness that is comparable to the thickness of the ferrite plate 124 described later from the viewpoint of protecting the side surface of the ferrite plate 124 from being exposed.

  As described above, the organic resin film 121 around which the magnetic sheet 122 is wound via the acrylic adhesive sheet 123 has a recess 121a formed therein.

  Subsequently, as shown in the cross-sectional view of FIG. 2B, the ferrite plate 124, which is formed by sintering the ferrite material and is processed into a plate shape that matches the recess 121a, is disposed so as to be engaged with the recess 121a. The ferrite plate 124 may be simply disposed in the recess 121a, but the surface of the ferrite plate 124 is protected by bonding via the acrylic adhesive sheet 125 as shown in FIG. Particularly preferable from the viewpoint.

  Subsequently, as shown in the cross-sectional view of FIG. 2C, the ferrite plate 124 engaged with the recess 121a includes a magnetic sheet 122 positioned on the side surface of the ferrite plate 124 so that polyethylene terephthalate (PET) is included. An organic resin film 126 made of an organic resin such as) is attached using an acrylic adhesive sheet 127.

  Through the manufacturing process as described above, the magnetic sheet 122 is wound on the side surface of the ferrite plate 124 so as to overlap the outer peripheral portion 11c of the antenna coil 11a, and the upper and lower surfaces of the ferrite plate 124 are organically arranged to include the magnetic sheet 122. Since the conductive resin films 121 and 126 are attached, the magnetic material 12 having a desired size and protected without exposing the surface of the ferrite plate 124 can be manufactured.

  Further, since the magnetic material 12 is wound on the side surface of the ferrite plate 124 so that the magnetic sheet 122 overlaps the outer peripheral portion 11c of the antenna coil 11a, the ferrite powder that can be peeled off from the side surface of the ferrite plate 124 is diffused. Can be prevented.

  Here, in terms of simply protecting the side surface of the ferrite plate 124, a film such as PET may be used instead of the magnetic sheet 122, but such an organic resin film does not have a property of attracting a magnetic field. The communication characteristics will be deteriorated. On the other hand, the magnetic material 12 according to the present embodiment is wound around the side surface of the ferrite plate 124 so that the magnetic sheet 122 overlaps with the outer peripheral portion 11c of the antenna coil 11a. It is possible to maintain good magnetic characteristics that draw the magnetic field into the portion 11c.

  In this way, by winding the magnetic sheet 122 on the side surface of the ferrite plate 124, it is possible to suppress the deterioration of the characteristics that draw the magnetic field into the antenna coil 11a, but when compared with the ferrite plate 124 and the magnetic sheet 122 Since the loss factor of the ferrite plate 124 is lower, the width of the magnetic sheet 122 is preferably as small as possible from the viewpoint of realizing good magnetic properties in the entire magnetic material 12. On the other hand, from the viewpoint of making the film material covering the outer shape of the ferrite plate 124 as difficult as possible to peel off, it is preferable that the width of the magnetic sheet 122 is as large as possible.

  The inventors of the present application pay attention to the above-described two viewpoints, and when the area ratio obtained by dividing the area surrounded by the magnetic sheet 122 by the area of the ferrite plate 124 is 6.64 or less, good magnetic characteristics are obtained. I found out that it could be realized.

  Below, the characteristics of the magnetic material manufactured based on the design guidelines described above were evaluated for the antenna substrate 101 as shown in FIG.

  As shown in FIG. 3, the antenna substrate 101 has an outer shape of 36 [mm] × 29 [mm] and a thickness of 0.09 [mm]. And have been implemented.

  The antenna coil 102 has a rectangular area of 36 [mm] × 29 [mm]. The antenna coil 102 has a film thickness of 35 [μm] coated with 25 [μm] of PI (polyimide), and a conductor having a width of 0.31 [mm] is 0.12 [mm] between adjacent conductors. ], That is, the pattern pitch is 0.42 [mm] and the number of windings is four.

  In order to draw a magnetic field into the antenna coil 102 mounted on the antenna substrate 101 having such a configuration, an overlapping region 104 overlapping the magnetic material 12 was set. This overlapping region is a region in which the outermost peripheral portion is located further 0.3 [mm] outside in the plane direction from the position of the outermost conductive wire of the antenna coil 102. Specifically, as shown in FIG. 4, the overlapping region 104 has a substantially rectangular shape having a width of 36 [mm] and a length of 29 [mm]. The magnetic material is formed by winding the magnetic sheet 104b around the ferrite plate 104a so that the outer shape coincides with the overlapping region 104. A magnetic material is manufactured with such a superimposed region 104 as a specified size.

  As the magnetic material, a ferrite plate and a magnetic sheet having a relative complex permeability of the following value in a magnetic field with an oscillation frequency of 13.56 MHz were used. That is, the ferrite plate used had a complex part with a real part μ ′ of 119 and an imaginary part μ ″ of 1.33. The magnetic sheet was made of Fe—Si—Cr and had a relative complex permeability. The real part μ ′ is 40 and the imaginary part μ ″ is 1.

  Magnetic materials A to C manufactured based on the design guidelines described above have the following configuration.

<Magnetic material A>
The magnetic material A is made of a ferrite plate having a thickness of 0.1 [mm], and the width in the plane direction is 0.1 [mm] so as to coincide with the outer peripheral shape of the overlapping region 104 on the side surface of the ferrite plate. A magnetic sheet made of Fe-Si-Cr is wound, and a PET film having a thickness of 0.04 [mm] is attached to the upper and lower surfaces of the ferrite plate so as to include the magnetic sheet. The area ratio obtained by dividing the area surrounded by the magnetic sheet of the magnetic material A by the area of the ferrite plate wound by the magnetic sheet is 1.34. Note that an acrylic ADH sheet having a thickness of 0.03 [mm] was used as an adhesive for bonding the members.

<Magnetic material B>
The magnetic material B is made of a ferrite plate having a thickness of 0.1 [mm], and the width in the plane direction is 0.2 [mm] so as to coincide with the outer peripheral shape of the overlapping region 104 on the side surface of the ferrite plate. A magnetic sheet made of Fe-Si-Cr is wound, and a PET film having a thickness of 0.04 [mm] is attached to the upper and lower surfaces of the ferrite plate so as to include the magnetic sheet. The area ratio obtained by dividing the area surrounded by the magnetic sheet of the magnetic material B by the area of the ferrite plate wound by the magnetic sheet is 2.68. Note that an acrylic ADH sheet having a thickness of 0.03 [mm] was used as an adhesive for bonding the members.

<Magnetic material C>
The magnetic material C is made of a ferrite plate having a thickness of 0.1 [mm], and the width in the plane direction is 0.5 [mm] so as to coincide with the outer peripheral shape of the overlapping region 104 on the side surface of the ferrite plate. A magnetic film made of Fe—Si—Cr is wound, and a PET film having a thickness of 0.04 [mm] is attached so that the upper and lower surfaces of the ferrite plate include the magnetic sheet. The area ratio of the magnetic material C obtained by dividing the area surrounded by the magnetic sheet by the area of the ferrite plate wound by the magnetic sheet is 6.64. Note that an acrylic ADH sheet having a thickness of 0.03 [mm] was used as an adhesive for bonding the members.

  In order to evaluate the communication characteristics of the magnetic materials A to C described above, the comparative magnetic materials D to G having the following configurations were used.

<Magnetic material D>
The magnetic material D is made of a ferrite plate having a thickness of 0.1 [mm], and the width in the surface direction is 0.2 [mm] so as to coincide with the outer peripheral shape of the overlapping region 104 on the side surface of the ferrite plate. A PET film having a thickness of 0.04 [mm] was adhered to the upper and lower surfaces of the ferrite plate so as to include the film wound on the side surface of the ferrite plate. Is. Note that an acrylic ADH sheet having a thickness of 0.03 [mm] was used as an adhesive for bonding the members.

<Magnetic material E>
The magnetic material E is made of a ferrite plate having a thickness of 0.1 [mm], and the width in the plane direction is 0.5 [mm] so as to coincide with the outer peripheral shape of the overlapping region 104 on the side surface of the ferrite plate. A PET film having a thickness of 0.04 [mm] was adhered to the upper and lower surfaces of the ferrite plate so as to include the film wound on the side surface of the ferrite plate. Is. Note that an acrylic ADH sheet having a thickness of 0.03 [mm] was used as an adhesive for bonding the members.

<Magnetic material F>
The magnetic material F is made of a ferrite plate having a thickness of 0.1 [mm] and matching the outer peripheral shape of the overlapping region 104, and a PET film having a thickness of 0.04 [mm] on the upper and lower surfaces of the ferrite plate. Is affixed. Note that an acrylic ADH sheet having a thickness of 0.03 [mm] was used as an adhesive for bonding the members.

<Magnetic material G>
The magnetic material G is a magnetic sheet made of Fe—Si—Cr having a width in the surface direction of 0.1 [mm] so as to coincide with the outer peripheral shape of the overlapping region 104 on the side surface of the magnetic sheet instead of the ferrite plate. A PET film having a thickness of 0.04 [mm] is attached so as to include a magnetic sheet on the upper and lower surfaces of the ferrite plate. Note that an acrylic ADH sheet having a thickness of 0.03 [mm] was used as an adhesive for bonding the members.

<Evaluation>
With respect to the magnetic materials A to G described above, with respect to the presence or absence of ferrite powder powder as an evaluation index of the coverage of the ferrite plate, and the communication characteristics of the antenna module incorporating each magnetic material, the following Table 1 is used. evaluated. Here, the “maximum communicable distance” is a value indicating the maximum communicable distance between the reader / writer and the antenna module at an oscillation frequency of 13.56 [MHz]. The larger this value, the better the communication characteristics. .

  The frequency of the magnetic field transmitted from the reader / writer is 13.56 MHz as described above. However, when communication is performed by inductive coupling, communication is performed using a frequency component higher than 13.56 MHz. Therefore, the dynamic characteristics of the antenna module are shown in FIG. In FIG. 5, the horizontal axis indicates the frequency of the magnetic field, the vertical axis indicates the maximum communicable distance according to the frequency, and the graphs B to G indicate the communication characteristics corresponding to the magnetic materials B to G, respectively. Yes. In addition, since the communication characteristic of the magnetic material A shows the characteristic similar to the magnetic material B, it did not show in FIG.

  The magnetic material F according to the comparative example realizes good communication characteristics because the size of the ferrite plate occupying the magnetic material is the largest among the evaluated examples, but the side surface of the ferrite plate is not protected. The ferrite powder has fallen off.

  On the other hand, the magnetic materials A to C according to the examples and the magnetic materials D, E, and G according to the comparative examples are formed of the ferrite powder because the ferrite plate is covered with the magnetic sheet and the organic resin film. There was no powder fall.

  In addition, the magnetic materials A to C according to the example had the maximum communicable distance similar to that of the magnetic material F, and could sufficiently maintain the magnetic characteristics of the outer peripheral portion of the antenna substrate.

  On the other hand, the magnetic material D according to the comparative example has a shorter maximum communicable distance than the magnetic materials A to C according to the example, and sufficiently suppresses the deterioration of the magnetic characteristics of the outer peripheral portion of the antenna substrate. could not. In addition, the magnetic material E according to the comparative example has a shorter maximum communicable distance than the magnetic material C in which the width of the film wound around the ferrite plate is the same, and sufficiently maintains the magnetic characteristics of the outer peripheral portion of the antenna substrate. could not.

  Moreover, although the ferrite material was not used and the magnetic material G which consists only of a magnetic sheet did not produce powder fall, it was not able to maintain sufficient magnetic characteristics.

  As is clear from this evaluation, in terms of simply protecting the side surface of the ferrite plate, a film such as PET may be used instead of the magnetic sheet like the magnetic material E described above. Communication characteristics could not be maintained due to lack of magnetic field pulling characteristics. Note that the magnetic material D achieves good communication characteristics because the width of the PET film wound around the side surface of the ferrite plate is adjusted so that the ferrite plate overlaps the outermost conductor wire of the antenna coil Because it is. That is, when the width of the PET film is 0.3 [mm] or more like the magnetic material E, the outermost conductor of the antenna coil does not overlap the ferrite plate, and as a result, good communication characteristics cannot be maintained. .

  On the other hand, the magnetic materials A to C are wound on the side surface of the ferrite plate so that the magnetic sheet overlaps with the outer peripheral portion of the antenna coil 11, so that the outer peripheral portion of the antenna coil is overlapped with the ferrite plate. Even if it is not, since it is superimposed on the magnetic sheet, it was possible to suppress the deterioration of the magnetic characteristics of the outer peripheral portion of the antenna substrate.

  As is clear from the above results, the magnetic materials A to B manufactured so that the area ratio obtained by dividing the area surrounded by the magnetic sheet by the area of the ferrite plate wound by the magnetic sheet is 6.64 or less. C was as difficult as possible to peel off the resin material covering the outer shape of the ferrite plate, and good communication characteristics could be realized.

  In the above embodiment, the magnetic sheet is wound with a uniform width on the side surface of the ferrite plate, but the present invention is not limited to this. That is, in the magnetic material, if the area ratio obtained by dividing the area surrounded by the magnetic sheet by the area of the ferrite plate wound by the magnetic sheet is 6.64 or less, the outermost conductor of the antenna coil is the ferrite plate. Regardless of whether or not they are superimposed on each other, the resin material covering the outer shape of the ferrite plate is hardly peeled off as much as possible, and good communication characteristics can be realized.

  DESCRIPTION OF SYMBOLS 1 Antenna module, 2 Reader writer, 2a antenna, 2b Control board, 3 Case, 11 Antenna board, 11a Antenna coil, 11b Terminal part, 11c Outer peripheral part, 12 Magnetic material, 13 Communication processing part, 100 Wireless communication system, 101 Antenna substrate, 102 antenna coil, 103 terminal portion, 104 overlap region, 121 organic resin film, 121a recess, 122 magnetic sheet, 123 acrylic adhesive sheet, 124 ferrite plate, 125 acrylic adhesive sheet, 126 organic resin film, 127 Acrylic adhesive sheet, 200 ferrite plate, 201 processed surface, 202 mold, 204 chip

Claims (6)

The magnetic field transmitted from the transmitter is arranged at a position overlapping the antenna substrate on which the antenna coil that receives the magnetic field transmitted from the transmitter and is inductively coupled with the transmitter and becomes communicable is mounted. In the magnetic material that is drawn into the coil,
It consists of a ferrite plate that is made by sintering magnetic metal and processing it into a plate shape.
On the side surface of the ferrite plate, a magnetic sheet made of a magnetic alloy is wound so as to overlap with the outer periphery of the antenna coil,
An organic resin film is attached to the upper and lower surfaces of the ferrite plate so as to include a magnetic sheet wound around the side surface of the ferrite plate. The magnetic sheet is made of a magnetic alloy containing silicon,
2. The magnetic material according to claim 1, wherein the ferrite plate has a loss coefficient at an oscillation frequency of a magnetic field transmitted from the transmitter smaller than that of the magnetic sheet.   2. The magnetic material according to claim 1, wherein an area ratio obtained by dividing an area surrounded by the magnetic sheet by an area of the ferrite plate is 6.64 or less.   The magnetic sheet according to claim 3, wherein the magnetic sheet having a width of 0.5 [mm] or less is wound around a side surface of the ferrite plate so as to overlap with an outer peripheral portion of the antenna coil. material. The magnetic field transmitted from the transmitter is arranged at a position overlapping the antenna substrate on which the antenna coil that receives the magnetic field transmitted from the transmitter and is inductively coupled with the transmitter and becomes communicable is mounted. In the manufacturing method of the magnetic material drawn into the coil,
On the first organic resin film, a magnetic sheet made of a magnetic alloy is wound and pasted so as to overlap with the outer periphery of the antenna coil,
Sintering the magnetic metal, placing the ferrite plate processed into a plate shape that matches the shape of the recess formed in the organic resin film wound with the magnetic sheet, so as to engage with the recess,
A method for producing a magnetic material, comprising: adhering a second organic resin film to the ferrite plate so as to include the magnetic sheet positioned on a side surface of the ferrite plate. An antenna substrate mounted with an antenna coil that receives a magnetic field transmitted from a transmitter and is inductively coupled with the transmitter to enable communication;
A magnetic material disposed at a position overlapping the antenna substrate so as to draw a magnetic field transmitted from the transmitter into the antenna coil;
The magnetic material is a ferrite plate obtained by sintering a magnetic metal and processing it into a plate shape.
On the side surface of the ferrite plate, a magnetic sheet made of a magnetic alloy is wound so as to overlap with the outer periphery of the antenna coil,
An antenna module, wherein an organic resin film is attached to the upper and lower surfaces of the ferrite plate so as to include a magnetic sheet wound around a side surface of the ferrite plate.

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