JP5561336B2 - Antenna device and portable terminal - Google Patents

Description

  The present invention relates to an antenna device and a mobile terminal in RF-ID (Radio Frequency Identification) and NFC (Near Field Communication).

  In recent years, loop-shaped antennas are often used for portable terminals such as mobile phones and smartphones in order to read information on non-contact type IC cards and IC tags and to perform information on R / W.

  In these loop-shaped antennas, for example, when reading information from a non-contact IC card, the loop-shaped antenna is generally smaller than the non-contact IC card and the magnetic field capturing area (communication area) is narrow, so it may be difficult to read. there were.

  Accordingly, there is a combination of a loop antenna and a metal wire as an extension of the communicable area (see, for example, Patent Document 1).

JP 2008-28506 A

  However, in the above conventional structure, since the communicable area is expanded using the metal wire, there is an air area in the vicinity where the metal line does not exist in the expanded area.

  Therefore, when a transmission magnetic field from a non-contact IC card enters the air region, almost no dielectric electromotive force is generated in the loop antenna due to the magnetic flux from the IC card. As a result, even if the communication region is expanded, the air region However, the loop antenna may not be able to communicate with the IC card.

  In view of the above problems, an object of the present invention is to provide an antenna device and a portable terminal that have good communication performance in a communicable region while expanding the communicable region.

In order to solve the above-described problems, the present invention provides an insulating antenna substrate, a substantially rectangular planar antenna formed on the antenna substrate, in which a conductive wire is wound in a planar shape and a spiral shape from an inner opening, A U-shaped cut having substantially the same size as that of the opening along the magnetic sheet having a surface larger than the plane of the planar antenna and three sides excluding the side where the input / output terminals of the planar antenna are provided. A metal body having a notch on the outer periphery, and the antenna is arranged in the order of the metal body, the antenna substrate, the planar antenna, and the magnetic sheet when viewed from the communication side of the planar antenna. A device and a portable terminal.

  ADVANTAGE OF THE INVENTION According to this invention, what has favorable communication performance within a communicable area | region can be provided, expanding a communicable area | region.

The perspective view of the antenna apparatus in Example 1 of this invention The top view of the antenna apparatus in Example 1 of this invention The side view of the antenna apparatus in Example 1 of this invention The figure explaining the concept when radiating | emitting a magnetic field from the antenna apparatus in Example 1 of this invention The figure explaining the concept when the antenna apparatus in Example 1 of this invention receives a magnetic field The figure showing the magnetic field intensity which the antenna device in Example 1 of the present invention radiates The disassembled perspective view of the portable terminal using the antenna apparatus in Example 1 of this invention. The perspective view of the antenna apparatus in Example 2 of this invention The top view of the antenna apparatus in Example 2 of this invention Side view of the antenna device according to the second embodiment of the present invention. The figure explaining the concept when the antenna apparatus in Example 2 of this invention radiates | emits a magnetic field. The figure explaining the concept when the antenna apparatus in Example 2 of this invention receives a magnetic field The figure showing the magnetic field intensity which the antenna device in Example 2 of the present invention radiates The disassembled perspective view of the portable terminal using the antenna apparatus in Example 2 of this invention The figure showing the magnetic field intensity which another antenna apparatus in Example 2 of the present invention radiates

An antenna device and a mobile terminal of the present invention include an insulative antenna substrate, a substantially rectangular planar antenna formed on the antenna substrate, in which a conductive wire is wound in a planar shape and a spiral shape from an inner opening, A U-shaped notch having substantially the same size as the opening along the magnetic sheet having a surface larger than the plane of the planar antenna and three sides excluding the side where the input / output terminals of the planar antenna are provided A metal body having a portion on the outer periphery, and the metal body, the antenna substrate, the planar antenna, and the magnetic sheet are arranged in this order when viewed from the communication side of the planar antenna.

  Thereby, since the air area | region in a communicable area is reduced, expanding a communicable area | region, the antenna apparatus which has favorable communication performance in a communicable area | region can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
1 is a perspective view of an antenna device according to a first embodiment of the present invention, FIG. 2 is a top view of the antenna device according to the first embodiment of the present invention, and FIG. 3 is a side view of the antenna device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG.

  In the antenna device 1 shown in FIG. 1, a loop-shaped antenna pattern 3 is formed on an antenna substrate 2. In FIG. 1, the antenna pattern 3 has a case of 3 turns, but is not limited to 3 turns.

  Further, in order to reduce the influence when metal is arranged on the upper part of the antenna, the magnetic sheet 4 is arranged on the upper part of the antenna pattern 3.

The antenna pattern 3 is connected to the matching circuit and the input / output terminals of the IC by the input / output terminals 5 and 6.

  Here, the metal body 7 is formed so as to be connected to the outer periphery of the metal body 7, and is provided with a rectangular cutout portion 8 that matches the shape of the antenna. It has a letter shape.

  That is, the notch 8 is not formed so that a hole is provided in the metal body 7, but has a shape that is cut out from the outer periphery of the metal body 7.

  Then, the antenna substrate 2 and the antenna pattern 3 are arranged so as to substantially contact the metal body 7 so as to cover the notch 8 of the metal body 7, and the metal body 7, the antenna substrate 2, the antenna pattern 3, and the magnetic sheet 4 are arranged. They are stacked in order.

  Hereinafter, the shape of the antenna pattern 3 and the cutout portion 8 will be described in detail with reference to FIGS. 2 and 3.

  As is apparent from the figure, the size of the notch 8 is smaller than the outer shape of the antenna pattern 3 (the size of the outermost loop of the antenna pattern 3), and the opening of the antenna pattern 3 (antenna pattern 3). (The size of the innermost loop).

  That is, the notch 8 is approximately the same size as the opening of the antenna pattern 3.

  Then, the opening of the antenna pattern 3 is arranged so as to coincide with the notch 8, and the antenna pattern 3 is linear with one side of the metal body 7 on the side where the notch 8 is provided, as shown in FIG. It is trying to become.

  Further, as shown in FIG. 3, the antenna pattern 3 is disposed on the metal body 7 via the antenna substrate 2.

  By doing as mentioned above, although mentioned later, the electric current which generate | occur | produces in the metal body 7 can be utilized efficiently.

  Further, in this embodiment, the position of the notch 8 is arranged so as to be the center of the side of the portion where the notch is provided.

  Hereinafter, the configuration of the antenna device 1 will be described.

  First, the antenna substrate 2 will be described. The antenna substrate 2 is a base substrate on which electronic members such as the antenna pattern 3 and the input / output terminals 5 and 6 are mounted. In this embodiment, any substrate having insulation properties may be used. For example, polyimide, PET, glass epoxy substrate, etc. It is possible to form.

Next, the antenna pattern 3 will be described. The antenna pattern 3 is formed in a spiral shape. The spiral structure may be a spiral shape having an opening at the center, and the shape may be a circle, a substantially rectangle, or a polygon represented by a triangle or a rectangle. The antenna pattern 3 may be arranged on the same plane or may be laminated. With the spiral structure, the magnetic field generated from the reader / writer is linked to the opening to induce the induced power, and the electric signal is transmitted to the matching circuit and the IC chip connected to the input / output terminals 5 and 6. And communication with the reader / writer becomes possible. Further, the pattern material may be any conductive material such as gold, silver, copper, aluminum, nickel or other conductive metal wire, metal plate, metal foil, or metal cylinder. It can select suitably from etc., and can form by metal wire, metal foil, an electrically conductive paste, plating transcription | transfer, sputtering, vapor deposition, or screen printing.

  Next, the magnetic sheet 4 will be described. The magnetic sheet 4 is disposed on the upper part of the antenna pattern 3 and may have a circular shape, a substantially rectangular shape, or a polygonal shape represented by a triangle or a quadrangle. The magnetic sheet 4 is for reducing the influence when a metal body is disposed on the upper part of the magnetic sheet 4. The magnetic sheet 4 desirably covers the antenna pattern 3 completely, and covers the antenna pattern 3. As long as it is larger than the antenna pattern 3, for example, it may be the same size as the metal body 7.

  Moreover, as a material of a magnetic body, any of insulating magnetic bodies, such as a ferrite, or electroconductive magnetic bodies, such as an electromagnetic steel plate, may be sufficient.

  Next, the input / output terminals 5 and 6 will be described. The input / output terminals 5 and 6 are electrically connected to the antenna pattern 3. The material may be any material as long as it has conductivity, and is appropriately selected from conductive metal wires such as gold, silver, copper, aluminum, and nickel, metal plates, metal foils, and metal cylinders. It can be formed by metal wire, metal foil, conductive paste, plating transfer, sputtering, vapor deposition, or screen printing. The input / output terminals 5 and 6 are electrically connected to the matching circuit and the IC chip. As a connection method, a commonly used connection method such as connection with a pin or a spring, soldering, or connection with a connector is used. You can choose.

  Any material may be used as long as it has conductivity, and can be appropriately selected from conductive metal foil materials such as gold, silver, copper, aluminum, and nickel, and metal plate materials. , Plating transfer, sputtering, vapor deposition, or screen printing.

  Next, the operation concept of the antenna device of the present invention will be described with reference to FIGS.

  FIG. 4 is a conceptual diagram of the present invention when transmitting from an antenna. A current 9 flows from the external circuit to the antenna pattern 3 by a signal input to the input / output terminals 5 and 6, thereby generating a magnetic field 10. An eddy current 11 is generated in the metal body 7 in the direction of canceling the magnetic field 10. At this time, by providing the metal body 7 with a notch portion 8 along the opening of the antenna pattern 3, three sides of the notch portion are formed. The eddy current 11 flows in a direction opposite to the current 9 flowing in the antenna pattern 3, but the eddy current 11 flowing in a portion other than the notch portion 8 of the metal body 7 corresponds to the current 9 flowing in the antenna pattern 3. As a result, the antenna pattern is apparently enlarged, and the degree of coupling with the communication partner card is increased. As a result, the communication performance is improved.

  FIG. 5 is a conceptual diagram of the present invention when the antenna receives a magnetic field from the outside. An eddy current 13 flows along the outer periphery of the metal body 7 by the magnetic field 12 from the outside, and a magnetic field 14 is generated in the outer periphery of the metal body 7 by the eddy current 13. At this time, by providing the notch 8 along the opening of the antenna pattern 3 in the metal body 7, the magnetic field 14 as shown in FIG. A downward magnetic field 15 as shown in FIG. 5 is generated in the inner periphery of the pattern 3. At this time, an eddy current 16 is generated in the antenna pattern 3 in the direction in which the magnetic field 15 is canceled out. As a result, it becomes possible to receive more magnetic fields generated by the RW as the communication partner, and as a result, the communication performance is improved.

  FIG. 6 shows experimental results when comparing the antenna device 1 of the present invention with the antenna device without using the metal body 7. The measurement conditions are as follows. First, the antenna device 1 of the present invention is arranged upside down, and the input impedance is matched to 50Ω from the input / output terminals 5 and 6 through the matching circuit, and then 20 dBm is input from the signal generator. The size of the metal body 7 is 62 mm × 38 mm, and the outer size of the antenna pattern 3 is 20 mm × 20 mm.

  Next, a probe coil of one turn with a size of 72 mm × 42 mm is arranged above the antenna device 1, and both ends of the probe coil are connected to observation terminals of an oscilloscope and observed with a port impedance of 1 MΩ. When the magnetic field generated from the antenna device 1 is linked to the probe coil, an induced electromotive voltage is generated at both ends of the probe coil and is observed by the oscilloscope. The probe coil is disposed so that the center of the metal body 7 of the antenna device 1 and the center of the probe coil are opposed to each other.

  When the metal body 7 is not used, the center of the antenna pattern 3 and the center of the search coil are arranged to face each other. The horizontal axis of the graph of FIG. 6 is the distance between the antenna device 1 and the probe coil, and the vertical axis is the value of the peak-to-peak voltage of the voltage waveform observed with the oscilloscope. According to the graph of FIG. 6, the antenna device 1 of the present invention can generate a larger induced electromotive voltage than the antenna device in the case where the metal body 7 is not used, particularly in the vicinity of 20 mm or less. Can confirm a greater effect.

  FIG. 7 is an exploded perspective view of a mobile terminal (a mobile phone in this embodiment) using the antenna device according to the first embodiment of the present invention. The portable terminal 18 includes a liquid crystal panel 19, a button 20, a casing 23, a casing 24, a substrate 21 included therein, a battery 22, and the like, and the antenna device 1 is attached to the casing 24. The antenna device 1 is attached to the surface of the substrate 21 opposite to the direction in which the liquid crystal panel 19 is disposed. The metal body 7 is attached to the casing 24, and the antenna pattern 3 and the magnetic sheet 4 are stacked thereon.

  The metal body 7 does not have to be attached to the housing 24. However, since the characteristics deteriorate when the metal body 7, the substrate 21 and the metal component mounted thereon are brought close to each other, the metal body 7 and the substrate 21 and the metal mounted thereon are removed. It is desirable to keep the parts as far apart as possible.

  In addition, the casing 24 and the metal body 7 may be integrated, and the material of the casing 24 in that case may be any material as long as the metal body 7 has conductivity, such as gold, silver, copper, and aluminum. It can be appropriately selected from conductive metal foil materials such as nickel, metal plate materials, etc., and can be formed by metal foil, conductive paste, plating transfer, sputtering, vapor deposition, or screen printing.

  Further, the substrate 21 may be used in place of the metal body 7. In this case, the substrate 21 is attached to the surface of the substrate 21 opposite to the direction in which the liquid crystal panel is disposed, and the structure is magnetic under the substrate 21. The body sheet 4 and the antenna pattern 3 are arranged in this order.

  Furthermore, in this embodiment, since the metal body 7 is formed of a metal foil material or the like, for example, a notch is provided in the metal body 7 in accordance with the arrangement of the parts of the mobile terminal mounted on the camera or the like. Can be placed avoiding the placement of.

In addition, the metal body 7 is formed on the curved surface of the casing by using a material that can be bent, such as a metal foil material, or by directly forming the curved surface of the casing by sputtering or the like as described above. The antenna device can be freely designed as compared with a conventional antenna device that can be arranged along a curved surface and cannot be arranged on a curved surface.

(Example 2)
8 is a perspective view of the antenna device 1 according to the second embodiment of the present invention, FIG. 9 is a plan view of the antenna device according to the second embodiment of the present invention, and FIG. 10 is a plan view of the antenna device according to the second embodiment of the present invention. It is a side view.

  In the antenna device 1 shown in FIG. 8, a loop-shaped antenna pattern 3 is formed on an antenna substrate 2. In FIG. 8, the antenna pattern 3 has a case of 3 turns, but is not limited to 3 turns. Further, in order to reduce the influence when metal is arranged on the upper part of the antenna, the magnetic sheet 4 is arranged on the upper part of the antenna pattern 3. The antenna pattern 3 is connected to the matching circuit and the input / output terminals of the IC by the input / output terminals 5 and 6. The metal body 7 is disposed substantially in contact with the antenna substrate. The cutout portion 8 of the metal body 7 is cut out along the opening of the antenna pattern 3 when the antenna pattern 3 is arranged at the center of the metal body 7, and is slit from one side to the opposite side of the metal body 7. 17 is arranged in a shape. About the structure of the antenna apparatus 1, it is the same as that of Example 1 of this invention.

  Next, the operation concept of the antenna device of the present invention will be described with reference to FIGS.

  FIG. 11 is a conceptual diagram of the present invention when transmitting from an antenna. A current 9 flows from the external circuit to the antenna pattern 3 by a signal input to the input / output terminals 5 and 6, thereby generating a magnetic field 10. An eddy current 11 is generated in the metal body 7 in the direction of canceling the magnetic field 10. At this time, the metal body 7 is cut from the notch 8 along the opening of the antenna pattern 3 and the metal from one side of the notch 8. By providing the slits 17 on the outer periphery of the body 7, eddy currents 11 in the opposite direction to the current 9 flowing in the antenna pattern 3 flow on each side of the cutouts. Since the eddy current 11 flowing in each side is induced to the outer peripheral portion of the metal body 7, the eddy current 11 flowing in the outer peripheral portion of the metal body 7 is forward with respect to the current 9 flowing in the antenna pattern 3. As a result, the antenna pattern appears to be large, and the degree of coupling with the card that is the communication partner increases, resulting in improved communication performance.

  FIG. 12 is a conceptual diagram of the present invention when the antenna receives a magnetic field from the outside. An eddy current 13 flows along the outer periphery of the metal body 7 by the magnetic field 12 from the outside, and a magnetic field 14 is generated in the outer periphery of the metal body 7 by the eddy current 13. At this time, the notch 8 is provided in the metal body 7 along the opening of the antenna pattern 3, and the slit 17 is provided from one side of the notch 8 to the outer periphery of the metal body 7. Since a magnetic field 14 as shown in FIG. 12 is generated at the outer peripheral portion of the side, a downward magnetic field 15 as shown in FIG. 12 is generated at the inner peripheral portion of the antenna pattern 3. At this time, an eddy current 16 is generated in the antenna pattern 3 in a direction in which the magnetic field 15 is canceled. However, since the eddy current 16 is in a forward direction with the eddy current 13 flowing in the outer peripheral portion of the metal body 7, the antenna pattern appears to be large. As a result, it becomes possible to receive more magnetic fields generated by the RW as the communication partner, and as a result, the communication performance is improved.

  FIG. 13 shows experimental results when the antenna device 1 of the present invention is compared with the antenna device when the metal body 7 is not used. The measurement conditions are the same as in Example 1 of the present invention. According to the graph of FIG. 13, the antenna device 1 of the present invention can generate a larger induced electromotive voltage than the antenna device in the case where the metal body 7 is not used, particularly in the vicinity of 20 mm or less. Can confirm a greater effect.

FIG. 14 is an exploded perspective view of a portable terminal using the antenna device according to the second embodiment of the present invention. The structures of the portable terminal 18 and the antenna device 1 are the same as those of the first embodiment of the present invention. The antenna pattern 3 is preferably arranged at the center of the metal body 7. Even in this case, the metal body 7 does not have to be attached to the casing 24. However, when the metal body 7 and the substrate 21 and the metal parts mounted on the metal body 7 approach each other, the characteristics deteriorate, so the metal body 7 and the substrate 21 and It is desirable to keep the distance between the metal parts mounted on it as much as possible.

  In FIG. 1, the notch 8 is formed along the three sides of the opening of the antenna pattern 3. However, the notch 8 may be formed along the two sides of the opening of the antenna pattern 3. Good.

  FIG. 15 shows experimental results when comparing the antenna device 1 when the notch 8 of the metal body 7 is along two sides of the opening of the antenna pattern 3 and the antenna device when the metal body 7 is not used. . According to the graph of FIG. 15, the antenna device 1 according to the present invention has a larger induction when compared to the antenna device when the metal body 7 is not used even when the two sides of the opening of the antenna pattern 3 are along. A voltage can be generated.

  The antenna device of the present invention and the mobile terminal device using the antenna device have good communication performance in the communicable region while expanding the communicable region, and are thus useful for electronic devices such as mobile phones.

DESCRIPTION OF SYMBOLS 1 Antenna apparatus 2 Antenna board 3 Antenna pattern 4 Magnetic material sheet 5 Input / output terminal 6 Input / output terminal 7 Metal body 8 Notch

Claims (2)

An insulating antenna substrate;
A substantially rectangular planar antenna formed on the antenna substrate and having a conductive wire wound in a planar shape and a spiral shape from an inner opening;
A magnetic sheet having a surface larger than the plane of the planar antenna;
A metal body having a U-shaped cutout portion of the same size as the opening on the outer periphery so as to be along three sides excluding the side where the input / output terminals of the planar antenna are provided;
When viewed from the communication side of the planar antenna, the antenna device is arranged in the order of the metal body, the antenna substrate, the planar antenna, and the magnetic sheet. A portable terminal comprising the antenna device according to claim 1.

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