JP2006270681A - Portable equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide portable equipment for suppressing the fluctuation of communication characteristics between an antenna module and a reader/writer when they are adjacently faced to each other. <P>SOLUTION: A metallic layer 30 is installed at the incident side of an electromagnetic wave emitted from a reader/writer of a communication face CS of an antenna module 10 incorporated in a terminal main body 22. In the metallic layer 30, a magnetic field for communication is introduced to an antenna coil 15 of the antenna module 10, and a communicating status is secured. The metallic layer 30 is configured of a copper foil or the like, and attached to the predetermined position of the inside or outer surface of the terminal. Thus, it is possible to suppress of the failure of communication due to the position relation of the reader/writer and the terminal main body 22 when they are made adjacent to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a portable device such as a portable information terminal in which a non-contact communication medium using RFID (Radio Frequency Identification) technology is incorporated in a housing, and more specifically, a communication defect that may occur when close to an external antenna. It is related with the portable device which can eliminate.

  Conventionally, in the RFID technology represented by a non-contact IC card system, an antenna coil is built in a non-contact IC tag for identification such as an IC card and inductively coupled with a radio wave transmitted from an external reader / writer antenna. Thus, non-contact data communication is performed.

  For this type of non-contact IC tag, for example, an antenna module having an antenna coil formed in a loop shape on the surface of a base substrate is used (see Patent Document 1 below). This antenna module includes a magnetic core member and a metal shield plate as necessary, and can be used by being incorporated in a casing of a portable information terminal such as a cellular phone.

  This antenna module includes a signal processing circuit that processes and generates a signal received or transmitted by an antenna coil. This signal processing circuit is composed of components such as an IC chip including a memory storing information and the like, and is electrically connected to the antenna coil. This signal processing circuit may be incorporated into a control board of a device in which the antenna module is incorporated.

  During communication between the antenna module and the reader / writer, the antenna coil receives an electromagnetic wave having a predetermined frequency (for example, 13.56 MHz) radiated from the reader / writer, so that an induced current corresponding to the intensity of the electromagnetic wave is received. appear. This induced current is rectified in the signal processing circuit and converted into an information read voltage. The read information is modulated in the signal processing circuit and transmitted to the reader / writer via the antenna coil.

JP 2004-364199 A JP 2004-227046 A

  In recent years, for example, a non-contact IC tag using an RFID that operates at a frequency of 13.56 MHz has been required to have a reliable operating environment. For example, in communication characteristics, the communication distance is as long as possible, and the reader / writer and the tag face each other. There is a need for a wide planar communication area.

  However, in this type of non-contact IC tag (antenna module), it is known that the communication characteristics change depending on the relative position between them when communicating with the reader / writer. Specifically, in a state where the antenna module and the reader / writer are close to each other, communication between the antenna module and the reader / writer may be impossible depending on the positional deviation between the antenna center and the reader / writer antenna center. There is a case.

  In particular, when this type of antenna module is used by being incorporated in a casing of a portable information terminal or the like, it is affected by metal parts (parts) such as a battery pack or a control board that are originally incorporated in the casing, and the reader / The communication characteristics tend to vary depending on the relative position of the antenna module with respect to the writer.

  This invention is made in view of the above-mentioned problem, and makes it a subject to provide the portable apparatus which can suppress the fluctuation | variation of the communication characteristic between both at the time of the antenna module and reader / writer facing near.

  In solving the above-described problems, the present invention provides a portable device in which an antenna coil that performs communication by receiving electromagnetic waves of a predetermined frequency radiated from an external antenna is incorporated in a housing. A metal layer is provided on the electromagnetic wave incident side of the communication surface.

  The metal layer disposed in the communication space between the external antenna and the antenna coil inside the housing exhibits an electromagnetic shielding function that reflects and absorbs an electromagnetic field generated from the external antenna. The inventors of the present invention have confirmed that the electromagnetic field affected by the metal layer is induced to the antenna side by the positional relationship between the metal layer and the antenna coil, thereby enhancing the coupling.

  Thereby, the malfunction of the communication characteristic resulting from the relative position between an external antenna and the antenna coil inside a housing | casing can be suppressed, and the stable proximity communication (for example, communication distance is 0-30 mm) between both is attained. At the same time, the maximum communication distance between the external antenna and the antenna coil inside the housing can be improved as compared with the case where no metal layer is provided.

  The metal layer can be disposed in a facing gap between the external antenna and the antenna coil. In particular, it is arranged at a position for guiding a communication magnetic field to the antenna coil, such as a position covering a part of the antenna coil or an outer peripheral side of the antenna coil. As a formation part of a metal layer, the inside of a housing | casing or the outer surface of a housing | casing is suitable.

  Here, the “position for inducing the communication magnetic field to the antenna coil” means the metal layer where the external antenna and the antenna coil are coupled via the magnetic field component generated by the induced current (eddy current) on the surface of the metal layer. Or by reflecting or absorbing electromagnetic waves radiated from an external antenna on the front and back surfaces of the metal layer to form a magnetic field distribution space in which the communication magnetic field reaches the antenna coil. This refers to the formation position.

  The metal layer is made of a metal foil such as copper foil or aluminum foil, a metal sheet, a metal plate or the like having a relatively small layer thickness, so that it can be advantageously incorporated into a portable device. Further, the shape of the metal layer may be a crank shape or a coil shape as well as a circular shape and a rectangular shape. Examples of the portable device include a portable information terminal represented by a portable phone, a portable audio player, a portable game machine, and the like.

  As described above, according to the portable device of the present invention, it is possible to suppress a communication failure when the external antenna is close to the antenna coil inside the housing. In addition, the maximum communication distance between the external antenna and the antenna coil inside the housing can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are an exploded perspective view and a side sectional view showing a configuration of an antenna module 10 for contactless data communication according to an embodiment of the present invention. First, the overall configuration of the antenna module 10 will be described.

  The antenna module 10 according to the present embodiment has a laminated structure of a base substrate 14 as a support and a magnetic core member 18. The base substrate 14 and the magnetic core member 18 are laminated via the double-sided adhesive sheet 13. In addition, illustration of the double-sided adhesive sheet 13 is abbreviate | omitted in FIG.

  The base substrate 14 is made of an insulating flexible substrate made of a plastic film such as polyimide, polyethylene terephthalate (PET), or polyethylene naphthalate (PEN), but may be made of a rigid substrate such as glass epoxy. Good.

  An antenna coil 15 wound in a loop shape in a plane is mounted on the base substrate 14. The surface on one side of the base substrate 14 is a communication surface CS (FIG. 2) for communicating with a transmission / reception antenna section of a reader / writer as an external antenna, and the surface on the opposite side of the base substrate 14 is a magnetic core. The laminated surface on which the member 18 is provided.

  The antenna coil 15 is a non-contact communication antenna coil for a non-contact IC tag function, and performs inductive coupling with a transmission / reception antenna unit of a reader / writer for communication (FIG. 4). The antenna coil 15 is formed of a metal pattern such as copper or aluminum patterned on the base substrate 14.

  In the present embodiment, the antenna coil 15 is composed of a loop portion wound in a plane and a wiring portion for electrical connection with a signal processing circuit portion 16 to be described later, but only the loop portion is shown in the figure. ing.

  The antenna module 10 can be provided with a second antenna coil for a reader / writer function. In this case, the second antenna coil may be used also as the above-described antenna coil 15 or may be separately provided on the inner peripheral side or the outer peripheral side of the antenna coil 15. Alternatively, the antenna coil 15 and the second antenna coil may be arranged separately on the front surface side and the back surface side of the base substrate 14.

  A signal processing circuit unit 16 is mounted on the surface of the base substrate 14 on the magnetic core member 18 side. The signal processing circuit unit 16 is disposed on the inner side of the antenna coil 15 and is electrically connected to the antenna coil 15 via the wiring portion.

  The signal processing circuit unit 16 includes a signal processing circuit necessary for contactless data communication, a memory unit such as an EEPROM storing information, and electric / electronic components such as a tuning capacitor. The signal processing circuit unit 16 may be configured by a plurality of component groups, or may be configured by a single IC chip. The signal processing circuit unit 16 is connected to a control board 24 (FIG. 3) of the portable information terminal 21 described later via an external connection unit 17 attached to the base board 14.

  Next, the magnetic core member 18 is made of, for example, a composite material formed in a sheet shape or a plate shape by mixing soft magnetic powder in an insulating binder such as a synthetic resin material or rubber and other additives. Examples of soft magnetic powders include Sendust (Fe-Al-Si series), Permalloy (Fe-Ni series), Amorphous (Fe-Si-B series, etc.), and Ferrite (Ni-Zn ferrite, Mn-Zn ferrite, etc.). It is applicable and can be used properly according to the intended communication performance and application.

  An opening (recess) 18 a for accommodating the signal processing circuit unit 16 mounted on the base substrate 14 is provided in the center of the magnetic core member 18. Further, on one side of the magnetic core member 18, a concave portion 18 b of the external connection portion 17 is formed at the time of lamination with the base substrate 14.

  Further, if necessary, a metal shield plate made of stainless steel or aluminum may be attached to the back surface side (the side opposite to the base substrate 14) of the magnetic core member 18. In this case, electromagnetic mutual interference with the built-in metal component of the portable device in which the antenna module 10 is incorporated can be suppressed.

  FIG. 3 is a schematic view of the state in which the antenna module 10 having the above-described configuration is incorporated in the portable information terminal 21 as viewed from the side of the terminal body 22.

  The illustrated mobile information terminal 21 is configured as a mobile phone including a terminal main body 22 and a panel unit 23 that is rotatably attached to the terminal main body 22. In FIG. 3, the terminal body 22 constitutes a casing made of a synthetic resin material, and the surface on the panel 23 side is an operation surface on which a numeric keypad button and the like are arranged, not shown.

  Inside the terminal body 22, a control board (printed wiring board) 24 for controlling the function or operation of the portable information terminal 21 and a battery pack 25 for supplying power are incorporated. Here, the battery pack 25 is a lithium ion battery, for example, and has a rectangular shape as a whole, and the outer casing is formed of a metal material such as aluminum.

  FIG. 4 is a schematic cross-sectional view illustrating a state during communication between the antenna module 10 built in the portable information terminal and an external reader / writer (R / W).

  When performing data communication with a reader / writer (R / W) using the antenna module 10, the back surface 22a (FIG. 3) of the terminal main body 22 is brought close to and opposed to the transmission / reception antenna unit 26 of the reader / writer. The electromagnetic wave (13.56 MHz) radiated from the transmission / reception antenna unit 26 of the reader / writer is incident on the communication surface CS of the antenna module 10, so that an induced current corresponding to the strength of the electromagnetic wave is applied to the antenna coil 15. appear. This induced current is rectified in the signal processing circuit unit 16 and converted into a read voltage for information recorded in the memory unit. The read information is modulated by the signal processing circuit unit 16 and transmitted to the transmission / reception antenna unit 26 of the reader / writer via the communication surface CS.

  Here, FIGS. 5 and 6 show the state of communication when the portable information terminal 1 having a conventional structure equipped with an antenna module for non-contact data communication and the reader / writer (R / W) are in close proximity (communication distance, for example, 5 mm). Is shown schematically. Note that, in the illustrated portable information terminal 1 having a conventional structure, portions (antenna module 10, battery pack 25, etc.) corresponding to the above-described components are denoted by the same reference numerals.

  In FIG. 5, the terminal body 22 is placed in the reader / writer (R / W) so that the center of the antenna coil 15 constituting the antenna module 10 coincides with the center of the transmission / reception antenna unit 26 of the reader / writer (R / W). It shows the state of being close to.

  In the example of FIG. 5, a part of the magnetic field component of the communication magnetic field H generated by the transmission / reception antenna unit 26 of the reader / writer (R / W) is a metal object such as the battery pack 25 in the terminal body 22. Attenuated by reflection, absorption, etc. However, when the remaining magnetic field component generates an induced current in the antenna coil 15 that is large enough to ensure communication with the reader / writer (R / W), the antenna module 10 and the reader / writer (R / W) ) Communication is possible.

  On the other hand, in FIG. 6, the terminal main body 22 is arranged such that the center of the antenna coil 15 constituting the antenna module 10 is located about 20 mm away from the center of the transmitting / receiving antenna unit 26 of the reader / writer (R / W) to the left side. Is shown in the state of being brought close to the reader / writer (R / W).

  In the example of FIG. 6, the magnetic field component H attenuated by the metal object such as the battery pack 25 in the terminal body 22 among the electromagnetic waves generated by the transmission / reception antenna unit 26 of the reader / writer (R / W) is shown in FIG. As a result, the induced current generated in the antenna coil 15 is small, and communication is impossible.

  Thus, in the conventional portable information terminal 1, the communication characteristics may vary depending on the relative position between the antennas when close to the reader / writer (R / W), and communication may become unstable. .

  Therefore, in the portable information terminal 21 of the present embodiment, the metal layer 30 is provided on the incident side of the electromagnetic wave with respect to the communication surface CS of the antenna coil 15 (FIG. 3). That is, in the example of FIG. 3, the metal layer 30 is provided on the back surface 22 a side (upper side in the drawing) of the terminal body 22 with respect to the communication surface CS of the antenna module 10.

  In the present embodiment, the metal layer 30 is formed of a conductive member having a relatively small layer thickness, such as a metal foil such as a copper foil or an aluminum foil, a metal sheet, or a metal plate. As shown in FIG. 3, the metal layer 30 is incorporated in the terminal main body 22, but may be attached to the inner surface side or the outer surface side of the back surface 22 a of the terminal main body 22.

  The size of the metal layer 30 is not particularly limited, and in this example, the metal layer 30 is formed with the same size and shape as the planar shape of the antenna module 10, but the communication characteristics and specifications of the antenna module 10, the structure of the terminal body 22, It is set as appropriate according to the internal configuration. The metal layer 30 may be electrically grounded or in a floating state.

  Further, as shown in FIG. 3, the metal layer 30 is disposed between the antenna module 10 and the battery pack 25, and as shown in the drawing, the antenna 30 is separated from the communication surface CS of the antenna module 10 by a predetermined gap. The coil 15 is formed at a position covering a part of the region. As will be described later, this metal layer 30 may be formed on the battery pack 25 side, for example, and separated from the outer peripheral side of the antenna coil 15 by a certain distance (FIG. 8).

  Hereinafter, the operation of the portable information terminal 21 of the present embodiment configured as described above will be described with reference to FIG.

  FIG. 7 schematically shows a state of communication when the portable information terminal 21 and the reader / writer (R / W) of the present embodiment are in proximity (communication distance, for example, 5 mm). The terminal main body 22 is brought close to the reader / writer so that the center of the antenna coil 15 constituting the antenna module 10 is located about 20 mm away from the center of the transmitting / receiving antenna unit 26 of the reader / writer to the left side. Is shown.

  In the example of FIG. 7, a part of the magnetic field component H out of the electromagnetic wave of a predetermined frequency (13.56 MHz) radiated from the transmitting / receiving antenna unit 26 of the reader / writer (R / W) is a battery pack in the terminal body 22. Under the influence of metal objects such as 25, it is attenuated by reflection and absorption. At this time, on the surface of the metal layer 30 provided in the facing gap between the reader / writer (R / W) and the antenna coil 15 so as to be positioned closer to the electromagnetic wave incident side than the communication surface CS of the antenna module 10. An induced current (eddy current) is generated by the application of an external magnetic field, and the magnetic field component H1 generated due to this generates an induced current in the antenna coil 15 of the antenna module 10.

  In this example, the metal layer 30 is disposed in close proximity to the antenna module 10 so as to cover a part of the antenna coil 15, so that the transmission / reception antenna unit of the reader / writer is generated via the magnetic field component H 1 generated in the metal layer 30. 26 and the antenna coil 15 of the antenna module 10 are inductively coupled, and serve as an auxiliary power supply source for communication between the antenna module 10 and the reader / writer (R / W).

  Note that the magnetic core member 18 constituting the antenna module 10 forms a magnetic path of a signal magnetic field generated around the antenna coil 15 and a metal component (wiring) on the control board of the antenna coil 15 and the portable information terminal 21. And electromagnetic interference with component electrodes, etc.) to ensure stable communication characteristics.

  As described above, the communication magnetic field component of the electromagnetic wave radiated from the reader / writer (R / W) is guided to the antenna coil 15 by the metal layer 30, so that the antenna module 10 and the reader / writer (R / W) Communication between W) is secured.

  Subsequently, in the example shown in FIG. 8, in the portable information terminal 21 of the present embodiment, the metal layer 30 is disposed in the facing gap between the reader / writer (R / W) and the antenna module 10. Compared to the example of FIG. 7, the metal layer 30 is arranged on the outer peripheral side of the antenna coil 15. The metal layer 30 and the battery pack 25 are not in contact with each other, and a constant gap is formed between them.

  In the example of FIG. 8, the terminal is arranged such that the center of the antenna coil 15 constituting the antenna module 10 is located about 20 mm away from the center of the transmitting / receiving antenna unit 26 of the reader / writer (R / W) to the left. A state in which the main body 22 is brought close to the reader / writer (R / W) (communication distance, for example, 5 mm) is shown.

  In this configuration, a part of the electromagnetic field H generated by the transmitting / receiving antenna unit 26 of the reader / writer (R / W) is attenuated by being reflected or absorbed by a metal object such as the battery pack 25 in the terminal body 22. Is done. At this time, the metal layer 30 reflects or absorbs electromagnetic waves radiated from the external antenna on the front surface (or back surface) of the metal layer 30, thereby creating a magnetic field distribution space in which the communication magnetic field reaches the antenna coil 15. Form.

  As described above, the communication magnetic field component of the electromagnetic wave radiated from the reader / writer (R / W) is guided to the antenna coil 15 by the metal layer 30, so that the antenna module 10 and the reader / writer (R / W) Communication between W) is secured.

  Therefore, according to the portable information terminal 21 of the present embodiment, the metal layer 30 that guides the communication magnetic field to the antenna coil 15 is provided on the incident side of the electromagnetic wave with respect to the communication surface CS of the antenna module 10. It is possible to effectively suppress communication problems caused by positional deviation between the antennas when close to the writer, and to improve the reliability of the RFID system. Further, by providing the metal layer 30 based on the same principle, it is possible to improve the maximum communication distance between the reader / writer and 10 antenna modules.

  Further, since the metal layer 30 is made of a metal foil or the like having a relatively small layer thickness, there are few restrictions when the terminal body 22 is incorporated into the terminal body 22, and a device can be configured in a compact manner. Furthermore, it is possible to suppress communication troubles when approaching at low cost.

  Examples of the present invention will be described below.

Example 1
Using a portable phone with a built-in antenna module for non-contact data communication, the communication state was checked when it was close to the reader / writer. In this example, as shown in FIG. 9, the experiment was performed in a state where the back surface 22a of the terminal body 22 was opposed to the transmission / reception antenna unit 26 of the reader / writer (R / W).

  The portable phone used in the experiment is “N901iC” (manufactured by NEC), and the reader / writer is “wireless card reader / writer” (EU-D2500 JR). The communication distance D (FIG. 11) between the antenna module 10 (terminal main body rear surface 22a) and the reader / writer was 2 mm and 5 mm. Then, with reference to the center position where the antenna center of the reader / writer and the antenna center of the antenna module 10 coincide with each other as shown in FIG. 9, the communication distance D is kept constant and 10 mm in the left-right direction of the reader / writer. The antenna module 10 (terminal main body 22) was moved at a pitch, and it was confirmed whether communication was stable at each position.

  Under the above-described experimental conditions, a rectangular (FIG. 10) copper foil having a length × width of 40 mm × 20 mm and a thickness of 35 μm was pasted with an adhesive tape as the metal layer 30 on the outer surface of the terminal main body back surface 22a. . As shown in FIG. 9, the copper foil is attached between the center of the antenna coil 15 and the left side of the copper foil 30 between a position covering a part of the antenna coil 15 and a position directly above the battery pack 25. An experiment was conducted in the case where the distance between the end portions was 5 mm, 10 mm, 15 mm, 20 mm, and 30 mm, respectively.

  The results of the experiment are shown in Table 1. In Table 1, ◯ indicates communication stability, Δ indicates communication stability limit, and X indicates communication instability. Table 1 also shows the results when the experiment was conducted without attaching the copper foil 30 and the maximum communication distances when the copper foil 30 was present.

  From Table 1, it can be seen that when there is no copper foil, communication becomes unstable when the antenna module 10 (terminal body 22) is moved 20 mm to 40 mm in the left direction with respect to the antenna center of the reader / writer. As described with reference to FIG. 6, a part of the electromagnetic wave radiated from the transmission / reception antenna unit 26 of the reader / writer is attenuated by the battery pack 25, so that the necessary power cannot be supplied to the antenna module 10. It is guessed from.

  On the other hand, in the experimental result of attaching the copper foil 30, an obvious effect is confirmed when the attaching position of the copper foil 30 is 5 mm, 10 mm, and 15 mm. An effect is recognized depending on conditions even at a position of 20 mm. As described with reference to FIG. 8, the signal magnetic field distribution is reformed due to the presence of the copper foil 30 at these positions, and the communication magnetic field component reaching the antenna coil 15 of the antenna module 10 increases. It is thought that communication is secured.

  Furthermore, it is recognized that the maximum communication distance is improved by providing the copper foil 30. Then, the interval from the start of reading of the signal when the reader / writer and the antenna module 10 are separated to the stable is shortened, and it can be predicted that the communication is stable even at a distance.

  In addition, as shown in Table 1, when the copper foil 30 is pasted, it is not always effective under all conditions, and the copper foil pasting position, the moving direction of the antenna module 10, and the moving distance. Variation in the effect is recognized. It is thought that this is because the various factors such as the size, specifications, installation position of the antenna module 10, the interior structure of the terminal body 20, and surrounding metal objects have a considerable influence on the communication environment. Accordingly, it can be considered that the communication position can be improved and the communication state can be improved by appropriately selecting the attachment position, shape, size, material, or the like of the metal layer 30 in close proximity communication.

In addition, it has been confirmed that a communication failure at the time of proximity between the antenna module 10 and the reader / writer similarly occurs in the antenna module alone. The reader / writer used at this time was RC-S440C, RC-S440A, RC-S310 (all manufactured by Sony).
Therefore, it is assumed that the same problem will occur when a portable device with an antenna module incorporated in the housing performs proximity communication with these three types of reader / writers. By providing the metal layer 30 according to the present invention, it is expected that it is possible to eliminate communication problems when close to the above three types of reader / writers.

(Example 2)
In the same manner as in Example 1, the communication state at the time of proximity to the reader / writer was confirmed using a portable phone with a built-in antenna module for non-contact data communication. In the present embodiment, as shown in FIG. 12, the experiment was performed with the front surface 22b (surface opposite to the back surface 22a) of the terminal body 22 facing the transmission / reception antenna unit 26 of the reader / writer (R / W). Went.

  The portable phone used in the experiment is “N901iC” (manufactured by NEC), and the reader / writer is “wireless card reader / writer” (EU-D2500 JR). The communication distance D (FIG. 12) between the antenna module 10 (terminal main body front surface 22b) and the reader / writer was 2 mm and 5 mm. Then, as shown in FIG. 12, with the center position where the antenna center of the reader / writer and the antenna center of the antenna module 10 coincided as a reference, the communication distance is kept constant and the reader / writer has a 10 mm pitch in the left-right direction. Then, the antenna module 10 (terminal main body 22) was moved, and it was confirmed whether communication was stable at each position.

  Under the above-described experimental conditions, a copper foil having a length × width of 40 mm × 20 mm and a thickness of 35 μm was attached to the outer surface portion of the terminal body front face 22a as a metal layer 30 with an adhesive tape. Since the electromagnetic wave radiated from the reader / writer (R / W) goes around the terminal body 22 and is incident on the front surface 22a, the metal layer 30 also enters the electromagnetic wave more than the communication surface CS of the antenna module 10 in this example. Will be located on the side. As shown in FIG. 12, the copper foil is attached between the center of the antenna coil 15 and the left side of the copper foil 30 between a position covering a part of the antenna coil 15 and a position directly above the battery pack 25. An experiment was conducted in the case where the distance between the end portions was 5 mm, 10 mm, 15 mm, 20 mm, and 30 mm, respectively.

  The results of the experiment are shown in Table 2. In Table 2, ○ indicates communication stability, Δ indicates communication stability limit, and X indicates communication instability. Table 2 also shows the results when the experiment was conducted without attaching the copper foil 30 and the respective maximum communication distances in the presence or absence of the copper foil 30.

  From Table 2, it can be seen that when there is no copper foil, communication becomes unstable when the antenna module 10 (terminal main body 22) is moved 40 mm or 50 mm to the left with respect to the antenna center position of the reader / writer. .

  On the other hand, in the experimental result of attaching the copper foil 30, an obvious effect has been confirmed when the attaching position of the copper foil 30 is 15 mm. This is considered that the signal magnetic field distribution is re-formed due to the presence of the copper foil 30 at these positions, and communication is ensured by an increase in the communication magnetic field component reaching the antenna coil 15 of the antenna module 10. Further, based on the same principle, the maximum communication distance between the reader / writer and the antenna module 10 is also improved depending on conditions.

  On the other hand, as shown in Table 2, when the copper foil 30 is pasted, it is not always effective under all conditions. The copper foil pasting position, the moving direction of the antenna module 10, and the moving distance Variation in the effect is recognized. It is thought that this is because the various factors such as the size, specifications, installation position of the antenna module 10, the interior structure of the terminal body 20, and surrounding metal objects have a considerable influence on the communication environment. Therefore, also in this embodiment, it is considered that the communication position can be suppressed and the communication state can be improved by appropriately selecting the attachment position, shape, size, material, etc. of the metal layer 30. it can.

  Although the embodiments and examples of the present invention have been described above, the present invention is of course not limited thereto, and various modifications can be made based on the technical idea of the present invention.

  For example, in the above embodiment, a metal foil such as a copper foil is used as the metal layer 30. However, the present invention is not limited thereto, and a metal foil is pasted on a non-conductive substrate such as a resin or glass, and this is connected to the terminal body. 22 may be incorporated.

  In the above embodiment, the portable information terminal 21 such as a portable phone or a PDA has been described as an example of the portable device. However, the present invention is not limited to this, and a non-contact type such as a portable audio player or a portable game machine is used. The present invention can be applied to a portable device that can be equipped with a communication antenna module.

1 is an exploded perspective view showing a configuration example of an antenna module 10 according to an embodiment of the present invention. 2 is a side sectional view of the antenna module 10. FIG. 1 is a schematic cross-sectional view illustrating a configuration of a mobile device including an antenna module 10. It is sectional drawing explaining the mode at the time of communication between the antenna module in a portable apparatus, and a reader / writer. It is sectional drawing explaining the effect | action of the conventional portable information terminal. It is sectional drawing explaining the effect | action of the conventional portable information terminal. It is sectional drawing explaining 1 effect | action of the portable information terminal 21 which concerns on embodiment of this invention. It is sectional drawing explaining 1 effect | action of the portable information terminal 21 which concerns on embodiment of this invention. It is a figure explaining Example 1 of this invention, and is a sectional side view explaining the relationship between a reader / writer and the terminal main body 22. FIG. It is a figure explaining Example 1 of this invention, and is a top view explaining the relationship between a reader / writer and the terminal main body 22. FIG. It is a figure explaining Example 1 of this invention, and is another sectional side view explaining the relationship between a reader / writer and the terminal main body 22. FIG. It is a figure explaining Example 2 of this invention, and is a sectional side view explaining the relationship between a reader / writer and the terminal main body 22. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Antenna module, 14 ... Base board, 15 ... Antenna coil, 16 ... Signal processing circuit part, 18 ... Magnetic core member, 21 ... Portable information terminal, 22 ... Terminal main body, 22a ... Back surface, 22b ... Front, 24 ... Control A substrate, 25 ... a battery pack, 26 ... a transmitting / receiving antenna part of a reader / writer, R / W ... a reader / writer.

Claims (10)

An antenna coil that performs communication by receiving electromagnetic waves of a predetermined frequency radiated from an external antenna is a portable device incorporated in the housing,
A portable device, wherein a metal layer is provided on the incident side of the electromagnetic wave with respect to the communication surface of the antenna coil. The portable device according to claim 1, wherein the metal layer is disposed in a facing gap between the external antenna and the antenna coil. The portable device according to claim 1, wherein the metal layer is provided at a position for guiding a communication magnetic field to the antenna coil. The mobile device according to claim 1, wherein the metal layer is formed inside or outside the housing. The portable device according to claim 1, wherein the metal layer is formed at a position covering a part of the antenna coil. The portable device according to claim 1, wherein the metal layer is formed on an outer peripheral side of the antenna coil. The mobile device according to claim 1, wherein the metal layer is a metal foil. The mobile device according to claim 1, wherein the housing is a terminal body of a mobile information terminal. The mobile device according to claim 1, wherein a magnetic core member is provided on a surface opposite to the communication surface of the antenna coil. The portable device according to claim 1, wherein a signal processing circuit unit is electrically connected to the antenna coil.

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