JP6187097B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device, and more particularly to an antenna device for short-range wireless communication.

  Near field communication called NFC (Near Field Communication) is communication performed between a terminal device that supports near field communication and a reader / writer. Specific examples of the short-distance wireless communication terminal device include a wireless communication device such as a mobile phone and a smartphone, and a non-contact IC card corresponding to card-type electronic money.

  The terminal device for short-range wireless communication is equipped with an antenna device for transmitting and receiving signals to and from the reader / writer. Patent Document 1 discloses an example of such an antenna device.

JP 2007-12589 A

  Short-range wireless communication is originally intended for transmission and reception of signals over a very short distance. However, in recent years, it has been demanded to increase the communication distance as much as possible in short-range wireless communication.

  Therefore, one of the objects of the present invention is to provide an antenna device for short-range wireless communication that can obtain a longer communication distance than conventional ones.

  In order to achieve the above object, an antenna device according to the present invention includes an antenna unit configured by a planar conductor pattern formed so as to surround a first region, and a magnetic core unit disposed in the first region. The magnetic core portion includes a first portion disposed in the same plane as the antenna portion.

  According to the present invention, since the magnetic core portion plays a role of increasing the inductance of the antenna device, it is possible to obtain a longer communication distance than a conventional product having no magnetic core portion.

  The antenna device may further include a base body having the antenna portion formed on a front surface, and the magnetic core portion further includes a second portion disposed farther from the base body than the planar conductor pattern. The first portion may be located between the second portion and the base body. In this way, the communication distance of the antenna device can be further extended. In this case, it is preferable that the first portion and the second portion have the same planar shape.

  In this antenna device, the base may be made of a nonmagnetic material, and may further include a magnetic substrate disposed so as to cover the back surface of the base. In this way, even if there is a metal body such as a battery on the back side of the base, it is possible to prevent a decrease in inductance of the antenna device due to the metal body.

  In the antenna device, the magnetic core portion may further include a third portion disposed in the same plane as the base, and the third portion and the magnetic substrate may be in contact with each other. The base may have an opening provided in the first region, and the third portion may be provided in the opening. In this way, the magnetic core portion and the magnetic substrate can be configured as an integral unit. In these cases, it is preferable that the first portion and the second portion have the same planar shape.

  In the antenna device, the base may be a magnetic substrate, and the first portion and the base may be in contact with each other. According to this, since the base body plays both the role as a base of the antenna part and the role of preventing the inductance reduction due to the influence of the metal body that may exist on the back side of the base body, the former role is made nonmagnetic. It is possible to make the antenna device thinner as compared with the case where the substrate is used and the latter role is played by the magnetic substrate disposed on the back surface of the non-magnetic substrate.

  In each of the antenna devices, the magnetic core portion may be further arranged in a second region located around the radial direction of the planar conductor pattern. According to this, the inductance of the antenna device can be further increased.

  According to the present invention, since the magnetic core portion plays a role of increasing the inductance of the antenna device, it is possible to obtain a longer communication distance than a conventional product having no magnetic core portion.

1 is a perspective view of an antenna device 1a according to a first embodiment of the present invention. (A) is sectional drawing of the antenna device 1a corresponding to the AA line shown in FIG. 1, (b) is a top view of the antenna device 1a. It is a disassembled perspective view of the antenna device 1b by the 2nd Embodiment of this invention. (A) is sectional drawing of the antenna device 1b, (b) is a top view of the antenna device 1b. It is a disassembled perspective view of the antenna device 1c by the 3rd Embodiment of this invention. (A) is sectional drawing of the antenna device 1c, (b) is a top view of the antenna device 1c. (I) is sectional drawing of the antenna device 1d by the 3rd Embodiment of this invention, (j) is a perspective view of the antenna device 1d. Further, (a), (c), (e), and (g) are cross-sectional views of the antenna device 1c in the course of manufacturing, and (b), (d), (f), and (h) are (a), (c), and (e), respectively. It is a perspective view of the antenna apparatus 1c corresponding to (g).

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, the antenna device 1a according to the first embodiment of the present invention includes a base 2a, an antenna unit 3, and a magnetic core 5a. The antenna device 1a is mounted on the above-described terminal device for short-range wireless communication (a wireless communication device such as a mobile phone or a smartphone, a non-contact IC card) together with a control device (not shown). While receiving the signal transmitted by the writer and outputting it to the control device, it plays a role of transmitting the signal generated by the control device to the reader / writer.

  The base 2a is a film-like member made of a nonmagnetic material such as a resin. As the resin constituting the substrate 2a, it is preferable to use polyimide. Specifically, a flexible printed board is preferably used as the base 2a, but even a member that does not have flexibility such as a flexible printed board can be used as the base 2a.

  The antenna unit 3 is constituted by a planar spiral conductor pattern formed on the front surface of the base 2a. A first region A1 shown in FIG. 2 is a central region of the antenna unit 3, and the planar conductor pattern constituting the antenna unit 3 is formed so as to surround the first region A1. The antenna unit 3 may be formed by printing a conductor pattern on the surface of the base 2a, or may be formed by etching a conductive foil formed on the entire surface of the base 2a. The number of turns of the antenna unit 3 may be one or more. 1 and 2 illustrate a case where the number of windings is four.

  Ends 3a and 3b of the antenna unit 3 shown in FIGS. 1 and 2B are connected to a control circuit (not shown). When an electromagnetic wave generated by a reader / writer (not shown) passes through the first region A1, an induced current is generated in the antenna unit 3. The induced current is supplied to a control circuit (not shown) through the end portions 3a and 3b. Thereby, transmission of a signal from the reader / writer to the terminal device is realized. On the other hand, when a signal generated by a control circuit (not shown) is supplied to the antenna unit 3 through the end portions 3a and 3b, an induction magnetic field is generated around the antenna unit 3 by electromagnetic induction. When the reader / writer receives this induced magnetic field, signal transmission from the terminal device to the reader / writer is realized.

  The magnetic core portion 5a is a magnetic material having a high magnetic permeability such as a magnetic powder-containing resin or a ferrite substrate, and is formed in a portion corresponding to the first region A1 on the front surface of the base 2a. As a specific method of forming the magnetic core portion 5a, application or screen printing is used when the magnetic core portion 5a is a magnetic powder-containing resin, and adhesive bonding is used when the magnetic core portion 5a is a ferrite substrate. Is preferred.

  As shown in FIG. 2A, the magnetic core portion 5a includes first and second portions 4a and 4b having the same planar shape. The first portion 4a is a portion arranged in the same plane as the antenna portion 3, and is located between the second portion 4b and the base 2a. The planar spread of the first portion 4a is set to be slightly smaller than the first region A1 in consideration of the need to provide a blank portion on the base 2a. The second portion 4b is a portion disposed farther from the base body 2a than the planar conductor pattern constituting the antenna unit 3, and is assumed to extend the first portion 4a in the direction opposite to the base body 2a. This corresponds to an extension of the first portion 4a.

  Due to the presence of the magnetic core portion 5a, the inductance of the antenna device 1a is increased as compared with the case where it is assumed that the magnetic core portion 5a does not exist. Therefore, in the antenna device 1a, it is possible to obtain a longer communication distance than when the magnetic core portion 5a is not provided. In particular, the second portion 4b has an effect of expanding the magnetic flux constituting the induction magnetic field generated around the antenna unit 3 in the reader / writer direction, so that the antenna device 1a can obtain a longer communication distance. It is possible.

  As described above, according to the antenna device 1a, the magnetic core portion 5a plays a role of increasing the inductance, so that it is possible to obtain a longer communication distance than a conventional product having no magnetic core portion. In particular, it is possible to obtain a longer communication distance by including the second portion 4b in the magnetic core portion 5a.

  Next, in the antenna device 1b according to the second embodiment of the present invention, an opening 2o is provided in the base 2a, as can be understood by comparing FIGS. 3 and 4 with FIGS. The difference from the antenna device 1a according to the first embodiment in that the magnetic core portion 5a further includes the third portion 4c and the magnetic substrate 6 is further provided, and the other points are the same as those of the antenna device 1a. is there. Hereinafter, the description will be given focusing on the difference.

  As shown in FIGS. 4A and 4B, the opening 2o of the base 2a is provided over almost the entire region corresponding to the first region A1 while leaving a necessary blank portion. In other words, the base body 2a has a shape in which only the planar conductor pattern forming area constituting the antenna section 3 and the necessary blank area are left around it, and other parts are cut off. Yes. The substrate 2a is bonded to the magnetic substrate 6 by a double-sided tape (not shown) attached to the back surface.

  The third portion 4c of the magnetic core portion 5a is made of a magnetic material disposed in the opening 2o. The planar shape of the third portion 4c is preferably the same as the planar shape of the first and second portions 4a and 4b. Since it is arranged in the opening 2o, the third portion 4c is arranged in the same plane as the base 2a. The first to third portions 4a to 4c of the magnetic core portion 5a are integrally formed, and the third portion 4c is the first when it is assumed that the first portion 4a extends in the direction of the base 2a. Corresponds to an extension of the portion 4a.

  The magnetic substrate 6 is a flat magnetic material disposed so as to cover the back surface of the base 2a, and is specifically formed of a ferrite substrate. As can be understood from FIG. 4A, the magnetic substrate 6 is in contact with the entire back surface of the base 2a and the entire back surface (surface on the magnetic substrate 6 side) of the third portion 4c of the magnetic core portion 5a. Yes. As described above, the base 2a and the magnetic substrate 6 are bonded by the double-sided tape (not shown).

  Here, in the present embodiment, it is preferable to integrally form the magnetic core portion 5a and the magnetic substrate 6 by processing one ferrite substrate. More specifically, it is preferable to form the magnetic core portion 5a and the magnetic substrate 6 by digging the surface of the ferrite substrate while leaving only the portion corresponding to the first region A1. In this case, the portion protruding without being dug down becomes the magnetic core portion 5a, and the portion located below the bottom surface of the dug-down portion becomes the magnetic substrate 6. However, the magnetic core portion 5a can be formed by a method of applying or screen printing magnetic powder-containing resin on the surface of the magnetic substrate 6 or a method of attaching another ferrite substrate.

  According to the antenna device 1b according to the present embodiment, in addition to the effect similar to that of the antenna device 1a according to the first embodiment, the conductor is close to the back surface side of the base 2a due to the shielding effect by the magnetic substrate 6. It is possible to prevent a decrease in inductance of the antenna device 1b due to the arrangement. This effect is particularly useful when the antenna device 1b is mounted on a wireless communication device such as a mobile phone or a smartphone. That is, in these wireless communication devices, a metal battery that can cause a decrease in inductance of the antenna device 1b is often arranged close to the back surface side of the base 2a. In the antenna device 1b, since the magnetic substrate 6 is provided on the back surface side of the base 2a, a decrease in inductance of the antenna device 1b due to such a metal battery is preferably prevented.

  Furthermore, according to the antenna device 1b, the opening 2o is provided in the base 2a, and the third portion 4c of the magnetic core portion 5a is disposed therein so that the magnetic substrate 6 and the third portion 4c are in contact with each other. Therefore, as described above, the magnetic core portion 5a and the magnetic substrate 6 can be integrally formed. Therefore, the manufacturing cost can be reduced.

  Next, the antenna device 1c according to the third embodiment of the present invention is further provided with a magnetic core portion 5b, as can be understood by comparing FIG. 5 and FIG. 6 with FIG. 3 and FIG. Unlike the antenna device 1b according to the second embodiment in that the area of the magnetic substrate 6 is enlarged corresponding to the part 5b, the other points are the same as the antenna device 1b. Hereinafter, the description will be given focusing on the difference.

  The magnetic core portion 5b is disposed in the second region A2 located around the radial direction of the antenna portion 3. Specifically, it is a linear magnetic body having a constant width arranged so as to surround the antenna portion 3 from the radial direction, and includes the first to third portions 4a to 4c, like the magnetic core portion 5a. The A groove 5g is formed between the magnetic core part 5a and the magnetic core part 5b, and the base body 2a and the antenna part 3 are accommodated in the groove 5g. The magnetic core portion 5b is preferably formed in the same process as the magnetic core portion 5a by the same formation method as the magnetic core portion 5a.

  According to the antenna device 1c, the presence of the magnetic core portion 5b realizes a higher inductance than the antenna device 1b. Therefore, according to the antenna device 1c, it is possible to obtain a longer communication distance than the antenna device 1b.

  Next, the antenna device 1d according to the fourth embodiment of the present invention is replaced with the base body 2a and the magnetic substrate 6 as can be understood by comparing FIGS. 7 (i) and (j) with FIGS. The antenna device 1c is different from the antenna device 1c according to the third embodiment in that the base 2b is included and the magnetic core portions 5a and 5b do not include the third portion 4c, and the other points are the same as those of the antenna device 1c. Hereinafter, the description will be given focusing on the difference.

  The base 2b is a flat magnetic material similar to the magnetic substrate 6 constituting the antenna device 1c, and specifically, a ferrite substrate. The antenna unit 3 according to the present embodiment is formed on the front surface of the base 2b. Further, the first portion 4a of the magnetic core portion 5a according to the present embodiment is in contact with the front surface of the base 2b.

  According to the antenna device 1d according to the present embodiment, the base 2b, which is a magnetic substrate, serves as a base for the antenna unit 3 and prevents an inductance drop due to the influence of a metal body that may exist on the back surface side of the base 2b. Play both roles. Therefore, the antenna device can be made thinner than the antenna device 1c in which the role of the former is assigned to the nonmagnetic base 2a and the role of the latter is assigned to the magnetic substrate 6 disposed on the back surface of the base 2a. .

  Hereinafter, a method for manufacturing the antenna device 1d will be described with reference to FIG.

  First, as shown in FIGS. 7A and 7B, a base 2b which is a magnetic substrate is prepared. Then, as shown in FIGS. 7C and 7D, the antenna portion 3 is formed on the front surface of the base 2b. This step is preferably performed by printing a conductor film.

  Next, as shown in FIGS. 7E and 7F, a resin film 7 is printed on the front surface of the base 2b. At this time, the film thickness of the resin film 7 is set so as to cover the entire antenna portion 3, while the formation regions of the magnetic core portions 5 a and 5 b need not be covered with the resin film 7. The resin film 7 thus formed serves to prevent the planar conductor pattern constituting the antenna unit 3 from moving during the printing of ferrite in the next process.

  Subsequently, as shown in FIGS. 7G and 7H, magnetic core portions 5a and 5b are formed on the front surface of the base 2b. This step is preferably performed by printing paste ferrite.

  Finally, by firing, the magnetic core portions 5a and 5b are fixed to the base 2b and the resin film 7 is evaporated. Through the above steps, the antenna device 1d shown in FIGS. 7 (i) and 7 (j) is completed.

  As described above, according to the manufacturing method shown in FIG. 7, it is possible to form the antenna device 1 d having the base 2 b that is a magnetic substrate in place of the nonmagnetic base 2 a and the magnetic substrate 6.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to such embodiment at all, and this invention can be implemented in various aspects in the range which does not deviate from the summary. Of course.

  For example, in each of the above embodiments, the planar shape of the first and second portions 4a and 4b of the magnetic core portion 5a is the same, but the planar shape of the first and second portions 4a and 4c is not necessarily the same. Not necessarily. As an example of such a case, for example, the upper surface of the magnetic core part 5a is swollen, and only a part of the upper end of the swollen part is located farther from the base body 2a than the planar conductor pattern constituting the antenna part 3. An example in which the second portion 4b is configured. The same applies to the planar shape of the third portion 4c, and it may not necessarily be the same as the planar shape of the first and second portions 4a, 4c.

  In each of the above embodiments, the planar shape of the antenna unit 3 is a rounded square, but the planar shape of the antenna unit 3 is determined by the shape of the space in the terminal device on which the antenna device is mounted. And can have various shapes such as a rectangle, a rounded rectangle, a circle, and an oval. The present invention is applicable regardless of the planar shape of the antenna unit 3.

1a to 1d Antenna device 2a Base (nonmagnetic member)
2b Substrate (magnetic substrate)
2o Opening 3 Antenna portion 3a, 3b Antenna end 4a First portion 4b of magnetic core portions 5a, 5b Second portion 4c of magnetic core portions 5a, 5b Third portion 5a of magnetic core portions 5a, 5b First Magnetic core portion 5b disposed in the region A1 of the magnetic core 5g disposed in the second region A2 Groove 6 Magnetic substrate 7 Resin film A1 First region A2 Second region

Claims (3)

An antenna portion constituted by a planar conductor pattern formed so as to surround the first region;
A base that is a magnetic body having the antenna portion formed on the front surface;
A magnetic core disposed in the first region,
The core portion is seen containing a first portion disposed in the antenna portion and the same plane, and a second portion located farther from the substrate than that of the antenna unit,
The first portion is located between the second portion and the substrate;
The antenna device, wherein the first portion and the base are in contact with each other . The antenna device according to claim 1 , wherein the first portion and the second portion have the same planar shape. The core unit, an antenna device according to claim 1 or 2, characterized in that it is further arranged in a second region located radially around the plane conductor pattern.

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