JP5862743B2 - Communication terminal device - Google Patents

Description

  The present invention relates to a communication terminal device that can be used in an RFID (Radio Frequency Identification) system that communicates with an external device via an electromagnetic field signal.

  In recent years, an RFID system using an HF band such as 13.56 MHz has been widely used as FeliCa (registered trademark) or NFC (Near Field Communication). For example, Patent Document 1 discloses an antenna device for an RFID system.

  FIG. 1 is a cross-sectional view of an antenna device portion of a communication terminal device 90 disclosed in Patent Document 1. This antenna device includes an asymmetrical coil having different winding intervals at two positions facing each other across the central portion of the winding region of the coil 71. On the side 71a having a large winding interval, the IC card 1 is provided. The magnetic body 72 is disposed on the opposite side to the surface of the input portion 94 facing the, and the magnetic body 72 is disposed on the surface on the input portion 94 side facing the IC card on the side 71b having a small winding interval. . A reader / writer circuit 50 is connected to the coil 71. The antenna device is disposed in an antenna housing recess 97 a formed in the metal casing 97 and is protected by a resin member 98. The magnetic field distribution by the antenna device is asymmetrical emphasized on the side 71a where the winding interval and the line width of the coil 71 are widened. Therefore, a good communication state can be secured in a direction perpendicular to the main surface of the antenna device.

Japanese Patent No. 3975918

  When the communication terminal device is held over a communication partner such as a reader / writer, the angle formed by the communication terminal device side antenna and the counterpart side antenna is not necessarily constant, and depending on the positional relationship (angular relationship), it may be possible to perform stable communication. May become impossible. Such a tendency is particularly prominent in the RFID system in which communication is performed between the communication terminal devices, rather than the RFID system in which communication is performed between the communication terminal device (reader / writer) and the IC card (IC tag).

  In the communication terminal device of Patent Document 1, as shown in FIG. 1, the antenna device is disposed in the antenna housing recess 97 a formed in the metal casing 97, so that magnetic flux is generated from a direction perpendicular to the main surface of the antenna device. It is difficult to ensure sufficient communication characteristics when the angle between the reader / writer side antenna and the terminal side antenna is increased and the distance between the antennas is increased. It is.

  The present invention has been made in view of the above circumstances, and its purpose is to suppress communication performance degradation and to communicate with a communication partner in a wide angle range regardless of the positional relationship (particularly the angular relationship) with the communication partner. It is an object of the present invention to provide a communication terminal device capable of performing

The communication terminal device according to the first aspect of the present application is:
An antenna coil including a magnetic core having a first main surface and a second main surface, and a coil conductor wound around the magnetic core and having a single winding axis, and a circuit A communication terminal device comprising: a substrate; and a housing that holds or holds the antenna coil and includes the circuit board therein,
The coil conductor is positioned on the first main surface side of the magnetic core and the second main surface side of the magnetic core, and is in the first main surface direction or the second main surface. A second conductor portion disposed at a position different from the first conductor portion in plan view from the direction,
The housing has two inner surfaces facing each other across the circuit board,
The antenna coil is located between any one of the two inner surfaces and the circuit board, and is arranged such that the second main surface side of the magnetic core faces the outer surface side of the housing ,
The circuit board has a planar conductor;
When the circuit board is viewed in plan, the end portion of the magnetic core is disposed in a region outside the end portion of the planar conductor .

  In the communication terminal device according to the second aspect of the present application, the second conductor portion of the coil conductor is more magnetic than the length A of the portion where the first conductor portion of the coil conductor is close to the magnetic core. The length B of the part close to the body core is configured to be large.

  In the communication terminal device according to the third aspect of the present application, the length A of the portion where the magnetic core and the coil conductor are close to the magnetic core is the first conductor portion of the coil conductor. It is configured to be smaller than the width C of the conductor portion.

  In the communication terminal device according to the fourth aspect of the present application, the antenna coil is arranged such that the first conductor portion of the coil conductor is positioned in the vicinity of an end portion in a longitudinal direction of the casing. Features.

  In a communication terminal device according to a sixth aspect of the present application, the magnetic core is a composite of magnetic powder and a resin material, or a sintered magnetic material that is divided into a plurality of pieces, which is molded into a sheet shape. It is characterized by that.

  A communication terminal device according to a seventh aspect of the present application is characterized in that a width of one end of the magnetic core is larger than a width of another portion.

  In the communication terminal device of the present invention, in particular, the coil conductor constituting the antenna coil is located on the first main surface side of the magnetic core and the second main surface side of the magnetic core, A second conductor portion disposed at a position different from the first conductor portion when viewed in plan from the main surface direction, and the antenna coil is configured such that the first main surface side of the magnetic core is on the planar conductor side. In addition, since the first conductor portion of the coil conductor is disposed in the vicinity of the upper end portion of the casing, wireless communication with the communication partner is performed with the end in the longitudinal direction of the casing facing the communication partner. In doing so, communication with a communication partner is possible in a wide angle range without largely depending on the positional relationship (particularly the angular relationship) with the communication partner.

FIG. 1 is a cross-sectional view of an antenna device portion of a communication terminal device disclosed in Patent Document 1. FIG. 2 is a diagram illustrating an antenna coil included in the communication terminal device according to the first embodiment. 2A is a plan view of the antenna coil, and FIG. 2B is a front view. FIG. 3 is a plan view in a state where the flexible base material 10 on which the coil conductor 9 is formed and the magnetic core 8 are separated. FIG. 4 is a diagram illustrating a configuration of a communication terminal device according to the first embodiment and an antenna device included in the communication terminal device. 4A is a plan view of the antenna device 101, FIG. 4B is a front view thereof, and FIG. 4C is a schematic cross-sectional view of the communication terminal device 201. FIG. 5 is a diagram schematically showing the state of the magnetic flux passing through the antenna coil when the angle θ shown in FIG. 4C is changed. FIG. 5A shows the case where θ = 90 °, and FIG. 5B shows the case where θ = 0 °. FIG. 6 is a diagram schematically showing the state of the magnetic flux passing through the antenna coil when the angle θ shown in FIG. 4C is changed. 6A is a case where θ = 0 °, and FIG. 6B is a perspective view schematically showing the state of magnetic flux when θ = 0 °. FIG. 7 is a diagram illustrating a state in which communication terminal apparatuses communicate with each other, FIG. 7A is a perspective view of a state in which communication terminal apparatuses communicate with each other, and FIG. 7B is a cross-sectional view thereof. FIG. 8 is a diagram illustrating another state in which communication terminal apparatuses communicate with each other, FIG. 8A is a perspective view of a state in which communication terminal apparatuses communicate with each other, and FIG. 8B is a cross-sectional view thereof. FIG. 9 is a diagram illustrating a configuration of an antenna coil according to the second embodiment. 9A is a plan view of the flexible base material 10 in a state where the coil conductor 9 is formed, FIG. 9B is a diagram showing the shape of the upper layer coil conductor portion 9S of the coil conductor 9, and FIG. ) Is a view showing the shape of the lower layer coil conductor portion 9U of the coil conductor 9, and FIG. 9D is a view showing a state where the lower layer coil conductor portion 9U and the upper layer coil conductor portion 9S are overlapped. FIG. 10A is a plan view of the antenna coil 22, and FIG. 10B is a front view of the antenna device provided with the antenna coil 22. FIG. 11A is a cross-sectional view of a main part of a communication terminal apparatus according to the third embodiment, and FIG. 11B is a front view of an antenna coil according to the third embodiment. 12A is a plan view of the antenna coil 24 according to the fourth embodiment, and FIG. 12B is a front view of the antenna coil 24 according to the fourth embodiment. FIG. 13A is a plan view of the magnetic core 8 provided in the antenna coil according to the fifth embodiment, and FIG. 13B is a plan view of the antenna coil 25 according to the fifth embodiment. FIG. 14A is a plan view of the magnetic core 8 provided in the antenna coil according to the sixth embodiment, and FIG. 14B is a plan view of the antenna coil 26 according to the sixth embodiment. FIG. 15 is a cross-sectional view of a main part of a communication terminal device according to the seventh embodiment. FIG. 16A is a perspective view of a communication terminal device 208 according to the eighth embodiment, and FIG. 16B is a sectional view thereof. FIG. 17A is a perspective view of a communication terminal apparatus 209 according to the ninth embodiment, and FIG. 17B is a cross-sectional view thereof. FIG. 18 is a cross-sectional view of a main part of a communication terminal device according to the tenth embodiment. FIG. 19 is a diagram showing a change in the coupling coefficient with the reader / writer antenna when the positional relationship between the magnetic core 8 and the coil conductor is changed. FIG. 20 is a front view of an antenna coil provided in the communication terminal device according to the eleventh embodiment. FIG. 21A, FIG. 21B, and FIG. 21C are front views of a comparative antenna coil.

<< First Embodiment >>
The communication terminal device according to the first embodiment is used as a mobile communication terminal such as a mobile phone terminal. FIG. 2 is a diagram illustrating an antenna coil included in the communication terminal device. The antenna coil 21 is used as an antenna for an HF band RFID system such as 13.56 MHz, for example. 2A is a plan view of the antenna coil, and FIG. 2B is a front view. The antenna coil 21 includes a magnetic core 8 having a first main surface MS1 and a second main surface MS2, and a coil conductor 9 wound around the magnetic core 8. The coil conductor 9 is positioned on the first main surface MS1 side of the magnetic core 8 and on the second main surface MS2 side of the magnetic core 8, and when viewed in plan from the main surface MS1 direction It has the 2nd conductor part 12 arrange | positioned in the position (position which does not overlap) different from the 1st conductor part 11. FIG.

  As shown in FIG. 2 (A), the magnetic core 8 is obtained by molding a composite of ferrite powder and resin material into a rectangular plate shape. The coil conductor 9 is formed by patterning a metal thin film such as copper, silver, or aluminum into a rectangular spiral shape on the surface of a flexible base material 10 such as PET. A terminal electrode 91 is formed at one end of the coil conductor 9, and a terminal electrode 92 is formed at the other end. These terminal electrodes 91 and 92 are connected to a power supply circuit (not shown).

  FIG. 3 is a plan view in a state where the flexible base material 10 on which the coil conductor 9 is formed and the magnetic core 8 are separated. As shown in FIG. 3, the flexible base 10 is provided with a rectangular opening AP at a position corresponding to the winding center of the coil conductor 9. The magnetic core 8 is inserted into the opening AP. Accordingly, the coil conductor 9 includes the first conductor portion 11 located on the first main surface MS1 side of the magnetic core 8 and the second conductor portion 12 located on the second main surface MS2 side of the magnetic core 8 respectively. Yes. The magnetic core 8 and the coil conductor 9 constitute an antenna coil 21.

  FIG. 4 is a diagram illustrating a configuration of a communication terminal device according to the first embodiment and an antenna device included in the communication terminal device. 4A is a plan view of the antenna device 101, and FIG. 4B is a front view thereof. FIG. 4C is a schematic cross-sectional view of the communication terminal device 201.

  As shown in FIG. 4A, the circuit board 20 has a thermosetting resin such as an epoxy resin as a base material, and a ground conductor GND as a flat conductor is provided in an inner layer thereof. Although not shown, on the front and back surfaces of the circuit board 20, various electronic components for constituting a mobile communication terminal are mounted in addition to the power feeding circuit connected to the antenna coil 21.

  As shown in FIG. 4A, the antenna coil 21 is mounted on the circuit board 20 with a bonding material in a state where the first main surface MS1 of the magnetic core 8 faces the circuit board 20. . Therefore, the first main surface MS1 of the magnetic core 8 faces the ground conductor GND. That is, the antenna coil 21 is disposed so as to overlap with the ground conductor GND in a state viewed from the direction of the first main surface MS1 or the second main surface MS2 of the magnetic core 8. However, the coil conductor 9 and the ground conductor GND are spaced apart by a gap G. By using the circuit board 20 in which the ground conductor GND is formed in the inner layer as described above, the gap G between the coil conductor 9 and the ground conductor GND can be obtained, and the azimuth angle θ = 0 ° of the magnetic flux as will be described later. The communication characteristics in

  The antenna coil 21 is disposed such that the first conductor portion 11 of the coil conductor 9 is closer to the ground conductor GND than the second conductor portion 12.

  Further, the antenna coil 21 is arranged so that the first conductor portion 11 of the coil conductor 9 is positioned in the vicinity of the end E in the longitudinal direction of the housing 200. The end portion in the longitudinal direction of the housing 200 is a portion that becomes an upper end portion in a state where the communication terminal device is gripped in a vertically long direction.

  Further, the magnetic core 8 of the antenna coil 21 is configured and arranged so that the end of the magnetic core 8 protrudes by a distance T from the end of the ground conductor GND when viewed in plan. This distance T is, for example, 1 to 5 mm (about 3 mm under average conditions). This structure makes it easier to pick up the magnetic flux.

  In this communication terminal device 201, a strong magnetic field is generated at the end portion (the upper end portion) E in the longitudinal direction of the housing 200, and good directivity is obtained at a wide angle from the A direction to the B direction in FIG. Have. Therefore, when the wireless communication with the communication partner is performed with the longitudinal end (the upper end) E of the housing 200 facing the communication partner, communication with the communication partner is possible in a wide angle range.

  5 and 6 are diagrams schematically showing the state of the magnetic flux passing through the antenna coil when the angle θ shown in FIG. 4C is changed. In FIGS. 5 and 6, the magnetic flux is indicated by a broken line.

  When θ = 90 °, as shown in FIG. 5A, the magnetic flux passes from the outer end of the magnetic core 8 (position near the end of the ground conductor GND) to the inner end. When θ = 45 °, as shown in FIG. 5B, the magnetic flux enters from the outer end of the magnetic core 8 and the second main surface MS <b> 2 and escapes to the inner end of the magnetic core 8. When θ = 90 ° and θ = 45 °, the magnetic flux passes through the winding center of the coil conductor.

  When θ = 0 °, as shown in FIG. 6A, a magnetic flux φe that enters the magnetic core 8 from the second main surface MS2 of the magnetic core 8 and escapes to the outer end portion is generated. Further, as shown in FIG. 6B, which is a perspective view, magnetic fluxes φs1 and φs2 entering the magnetic core 8 from the second main surface MS2 of the magnetic core 8 and exiting to the side of the ground conductor GND are generated. Arise. Thus, when θ = 0 °, the magnetic flux passes through the winding center portion of the coil conductor in the same manner as θ = 90 ° and θ = 45 °.

  FIG. 7 is a diagram illustrating a state in which communication terminal apparatuses communicate with each other, FIG. 7A is a perspective view of a state in which communication terminal apparatuses communicate with each other, and FIG. 7B is a cross-sectional view thereof. Communication is performed with the upper end portions E of the first communication terminal device 201A and the second communication terminal device 201B being close to each other. In this example, if the two communication terminal devices 201A and 201B are in a mirror-symmetrical relationship, the angle formed by the housing with respect to the mirror surface is approximately 45 °. The antenna coil 21 is located closer to the counterpart antenna than the ground conductor GND.

  As shown in FIG. 5B, the coil conductor of the antenna coil 21 is also linked to the magnetic flux in the 45 ° direction. Therefore, even if the upper end portions E of the communication terminal devices are diagonally opposed to each other as shown in FIG. Wireless communication can be performed between communication terminal apparatuses.

  FIG. 8 is a diagram illustrating another state in which communication terminal apparatuses communicate with each other, FIG. 8A is a perspective view of a state in which communication terminal apparatuses communicate with each other, and FIG. 8B is a cross-sectional view thereof. Communication is performed with the upper end portions E of the first communication terminal device 201A and the second communication terminal device 201B being close to each other. In this example, if the two communication terminal devices 201A and 201B are in a mirror-symmetrical relationship, the angle formed by the housing with respect to the mirror surface is approximately 90 °. Here, in FIG. 8A, the upper end portions E of the two communication terminal devices 201A and 201B are drawn so as to oppose each other at an angle. Opposing in parallel.

  As shown in FIG. 5 (A), the coil conductor of the antenna coil 21 also links with the magnetic flux in the 90 ° direction. Therefore, even if the upper end portions E of the communication terminal devices are directly opposed to each other as shown in FIG. Wireless communication can be performed between communication terminal apparatuses.

  In this way, communication can be performed within a wide range in which the communication terminal device is held over the antenna device on the communication partner side.

<< Second Embodiment >>
FIG. 9 is a diagram illustrating a configuration of an antenna coil according to the second embodiment.

  FIG. 9A is a plan view of the flexible base material 10 in a state where the coil conductor 9 is formed. The coil conductor 9 is formed on the upper surface of the flexible substrate 10.

  FIG. 9B shows the shape of the upper layer coil conductor portion 9S of the coil conductor 9. FIG. FIG. 9C is a diagram showing the shape of the lower layer coil conductor portion 9U of the coil conductor 9. FIG. 9D shows a state in which the lower layer coil conductor portion 9U and the upper layer coil conductor portion 9S overlap.

  Each of the lower layer coil conductor portion 9U and the upper layer coil conductor portion 9S has a substantially rectangular spiral shape, and an insulating layer is interposed between the lower layer coil conductor portion 9U and the upper layer coil conductor portion 9S. However, the inner end portion of the lower layer coil conductor portion 9U and the inner end portion of the upper layer coil conductor portion 9S are electrically connected, and both are connected in series. Thus, the coil conductor 9 is formed in a spiral around the coil conductor opening CW.

  The flexible base material 10 is provided with a terminal electrode 91 that is continuous with the outer end portion of the upper coil conductor portion 9S. In addition, a terminal electrode 92 that is electrically connected to the outer end of the lower layer coil conductor portion 9U is provided.

  The lower layer coil conductor portion 9U and the upper layer coil conductor portion 9S may be formed on both surfaces of the flexible base material 10 instead of being formed on one side of the base material of the flexible base material 10, respectively.

  As shown in FIG. 9A, an opening AP is formed in the flexible base material 10 at a position corresponding to the coil conductor opening CW.

  FIG. 10A is a plan view of the antenna coil 22, and FIG. 10B is a front view of the antenna device provided with the antenna coil 22.

  The magnetic core 8 is inserted through the opening AP of the flexible base material 10. This constitutes the antenna coil 22. The antenna device is configured by the antenna coil 22 being disposed close to or directly mounted on the circuit board 20. The antenna coil 22 is disposed so that the formation surfaces of the terminal electrodes 91 and 92 shown in FIG. 9A face the circuit board 20, and the terminal electrodes 91 and 92 are connected to the electrodes on the circuit board 20.

  In addition, when the lower layer coil conductor part 9U and the upper layer coil conductor part 9S of the coil conductor 9 shown in FIG. 9 are viewed in plan, the main parts of the lower layer coil conductor part 9U and the upper layer coil conductor part 9S do not overlap each other. Are arranged as follows. Therefore, the stray capacitance between the conductors of the coil conductor 9 can be reduced, and an antenna coil having desired characteristics can be configured.

<< Third Embodiment >>
In 3rd Embodiment, the example of arrangement | positioning and electrical connection of the antenna coil in the housing | casing of a communication terminal device is shown.

  FIG. 11A is a cross-sectional view of the main part of the communication terminal device, and FIG. 11B is a front view of the antenna coil. A coil conductor 9a is formed on the upper surface of the flexible substrate 10, and a coil conductor 9b is formed on the lower surface. These patterns are the same as those shown in FIG. 9 in the second embodiment. In the example shown in FIG. 9, two layers of coil conductors are formed on one side of the flexible base material, but in the example of FIG. 11, they are formed on both sides of the flexible base material and are connected via via electrodes at predetermined locations. Yes.

  As shown in FIG. 11A, the antenna coil 23 is affixed to the inner surface of the housing 200 of the communication terminal device. The antenna coil 23 is arranged such that the first conductor portion 11 located in the vicinity of the longitudinal end of the housing 200 is on the circuit board 20 side.

  The housing 200 is composed of upper and lower housings that can be separated by a plane parallel to the plane of the circuit board 20. The contact pin 31 erected on the circuit board 20 contacts the terminal electrode 91 of the coil conductor in a state where the upper casing to which the antenna coil 23 is attached is put on the lower casing. As a result, the power supply circuit provided on the circuit board 20 and the antenna coil 23 are electrically connected. With such a configuration, the gap G between the coil conductor and the ground conductor GND can be made larger. Therefore, in particular, the directivity in the θ = 0 ° direction can be improved as shown in FIG.

<< Fourth Embodiment >>
In 4th Embodiment, the example of the formation position of the terminal electrode of a coil conductor is shown.

  12A is a plan view of the antenna coil 24, and FIG. 12B is a front view. The position of the terminal electrode of the coil conductor is different from that of the antenna coil 21 shown in FIG. In the example of FIG. 12, the terminal electrodes 91 and 92 that are connection terminals to the power feeding circuit are arranged at positions that do not overlap the magnetic core 8 in plan view. For this reason, the contact pin hardly affects the transmission and formation of the magnetic flux in a state where the contact pin is in contact with the terminal electrodes 91 and 92. Moreover, it is preferable that both of the terminal electrodes 91 and 92 are brought close to one side portion of the magnetic core in a plan view (does not straddle the magnetic core 8).

<< Fifth Embodiment >>
FIG. 13A is a plan view of the magnetic core 8 provided in the antenna coil according to the fifth embodiment, and FIG. 13B is a plan view of the antenna coil 25 according to the fifth embodiment.

  The difference from the antenna coil 21 shown in FIG. 3 in the first embodiment is that one end of the magnetic core 8 is formed thicker (wider) than the other part.

  By using the magnetic core 8 having such a shape, the magnetic flux passing through the magnetic core 8 is strengthened, the magnetic field coupling with the antenna of the communication partner can be strengthened, and the maximum communicable distance is increased. Will improve. Here, in FIG. 13B, the antenna coil 25 is configured by bringing the thick portion of the magnetic core 8 close to the first conductor portion 11, but the thick portion of the magnetic core 8 is the second conductor portion. The antenna coil may be formed close to the antenna 12. The thickened part (the part to be widened) of the magnetic core 8 is not limited to either the part close to the first conductor part 11 or the part close to the second conductor part 12. Thus, by making one end of the magnetic core 8 thicker than the other part, the magnetic flux collection effect is enhanced and the communication performance is further improved. Further, by thickening the end portion of the magnetic core that is on the end portion side of the ground conductor, the magnetic resistance near the end portion of the ground conductor is lowered, and the magnetism collecting effect is increased.

  In the antenna coil 25 shown in FIG. 13, the entire one end portion of the magnetic core 8 is formed wide (thick), but this portion may have a trapezoidal shape that is wider toward the outside. Alternatively, a butterfly shape having a wide width from the center to both ends of the magnetic core 8 may be used.

<< Sixth Embodiment >>
FIG. 14A is a plan view of the magnetic core 8 provided in the antenna coil according to the sixth embodiment, and FIG. 14B is a plan view of the antenna coil 26 according to the sixth embodiment. The antenna coil 26 includes a flexible base material 10 on which a coil conductor is formed and a rectangular plate-shaped magnetic core 8. What differs from the antenna coil 25 shown in FIG. 13B is the structure of the magnetic core 8.

  The magnetic core 8 shown in FIG. 14 (A) is obtained by previously laminating a plate-like ferrite film with cut lines in a grid pattern, and breaking the cut pieces into small pieces. It is. The part delimited by the broken line in FIG. 14B represents a small piece of sintered magnetic material. With this configuration, the entire magnetic sheet 1 has flexibility. Therefore, the antenna coil provided with the magnetic sheet 1 can be easily arranged along the surface of the support base. For example, it can provide along the inner surface of the housing | casing of a portable terminal. Therefore, it can be easily assembled in various shapes of housings.

  In FIG. 14B, the antenna coil 22 is configured by bringing the thick portion of the magnetic core 8 close to the first conductor portion 11. However, as described in the fifth embodiment, the magnetic core 8 The portion to be thickened (the portion to be widened) is not limited to either the portion close to the first conductor portion 11 or the portion close to the second conductor portion 12. Thus, by making one end of the magnetic core 8 thicker than the other part, the magnetic flux collection effect is enhanced and the communication performance is further improved.

<< Seventh Embodiment >>
FIG. 15 is a cross-sectional view of a main part of a communication terminal device according to the seventh embodiment. In this example, the antenna coil 27 is attached to the curved surface inside the housing 200. In particular, as shown in FIG. 14, when a flexible magnetic core is used and a flexible coil conductor provided on a flexible substrate is used, the antenna coil 27 has flexibility, so that the housing It is not limited to a single plane in 200, but can be provided along the curved surface of the housing. For this reason, it can be easily incorporated into a housing having various shapes. In addition, since the antenna coil 27 is attached to the inner surface of the housing 200, the distance between the antenna coil 27 and the ground conductor GND in the circuit board 20 can be increased, and the magnetic flux passage area is increased. Can be secured.

<< Eighth Embodiment >>
The eighth embodiment shows an example applied to a clamshell communication terminal device.

  16A is a perspective view of the communication terminal device 208, and FIG. 16B is a cross-sectional view thereof. The casing of the communication terminal device 208 includes a top casing 200A and a bottom casing 200B. In this case, the antenna coil 21 is disposed near the upper end E of the top housing 200A. A liquid crystal display panel 41 is housed in the top housing 200A. Since the shield plate 41S is attached to the back surface of the liquid crystal display panel 41, the shield plate 41S corresponds to the planar conductor according to the present invention. The bottom casing 200B includes a key input unit 42 and a circuit board 20.

  With such a structure, when the top housing 200A and the bottom housing 200B are folded, the antenna coil 21 is located between the ground conductor GND of the bottom housing 200B and the shield plate of the top housing 200A. The antenna coil 21 can be used for wireless communication even in a folded state.

<< Ninth embodiment >>
In the ninth embodiment, an example applied to a slide-type communication terminal device is shown.

  17A is a perspective view of the communication terminal device 209, and FIG. 17B is a cross-sectional view thereof. The casing of the communication terminal device 209 includes a top casing 200A and a bottom casing 200B. In this case, the antenna coil 21 is disposed near the upper end E of the top housing 200A. A liquid crystal display panel 41 is housed in the top housing 200A. Since a shield plate is affixed to the back surface of the liquid crystal display panel 41, this shield plate corresponds to the planar conductor according to the present invention. The bottom casing 200B includes a key input unit 42 and a circuit board 20.

  The ground conductor of the circuit board 20 in the bottom housing 200B is patterned so that the portion that overlaps with the antenna coil 21 becomes a non-ground region when the top housing 200A is housed. With such a structure, even when the top housing 200A is stored, wireless communication can be performed using the antenna coil.

<< Tenth Embodiment >>
The tenth embodiment shows the relationship between the proximity position of the magnetic core to the coil conductor of the antenna coil and the coupling coefficient.

  FIG. 18 is a cross-sectional view of a main part of a communication terminal device according to the tenth embodiment. A coil conductor 9a is formed on the upper surface of the flexible substrate 10, and a coil conductor 9b is formed on the lower surface.

  As shown in FIG. 18, the antenna coil 23 is affixed to the inner surface of the housing 200 of the communication terminal device. Further, in this antenna coil 23, the second conductor portion 12 located in the vicinity of the end portion in the longitudinal direction of the housing 200 has the outer surface side of the housing 200 (the communication partner side, and the upper surface side in the direction of FIG. 18). It is arranged to face.

  The housing 200 is composed of upper and lower housings that can be separated by a plane parallel to the plane of the circuit board 20. The contact pin 31 erected on the circuit board 20 contacts the terminal electrode 91 of the coil conductor in a state where the upper casing to which the antenna coil 23 is attached is put on the lower casing. As a result, the power supply circuit provided on the circuit board 20 and the antenna coil 23 are electrically connected.

  What differs from the antenna coil 23 shown in FIG. 11 in the third embodiment is the proximity position of the magnetic core to the coil conductor of the antenna coil. Here, the length of the portion where the first conductor portion 11 of the coil conductor is close to the magnetic core 8 is represented by A, and the length of the portion where the second conductor portion 12 of the coil conductor is close to the magnetic core 8 is represented by B. , A <B. Further, the length A of the portion of the coil conductor where the first conductor portion 11 is close to the magnetic core 8 is configured to be smaller than the width C of the first conductor portion 11.

  According to this configuration, the invalid magnetic flux φi that is not linked to the antenna coil is reduced, and accordingly, the magnetic flux φa that is effectively linked is increased. Therefore, the coupling coefficient with a communication partner antenna such as a reader / writer antenna is increased.

  FIG. 19 is a diagram showing a change in the coupling coefficient with the reader / writer antenna when the positional relationship between the magnetic core 8 and the coil conductor is changed. The conditions for obtaining the measurement results are as follows.

[Magnetic core 8]
Length 15mm
Width 16mm
[Coil conductor]
External dimensions 15 × 20mm
Width of first conductor portion 11 C 2 mm
Width B of second conductor portion 12 2 mm
[Relationship with ground electrode]
3mm distance between magnetic core 8 and ground electrode GND
[Relationship with reader / writer antenna]
17mm distance from reader / writer antenna
The horizontal axis “magnetic core shift amount X” in FIG. 19 indicates the length A of the portion where the first conductor portion 11 of the coil conductor is close to the magnetic core 8 and the second conductor portion 12 is close to the magnetic core 8. It is the dimension subtracted from the length B of the part.

  Under this condition, as shown in FIG. 19, a high coupling coefficient is obtained when the magnetic core shift amount X is in the range of 2 to 7.5 mm. Here, the magnetic core shift amount X = 7.5 mm corresponds to a state in which the magnetic core 8 is close only to the second conductor portion 12 of the coil conductor. Therefore, in general, it can be said that it is effective to set the shift amount of the magnetic core in a range exceeding 0 and reaching the state in which the magnetic core 8 is only close to the second conductor portion 12 of the coil conductor.

  The relationship between the length A of the portion where the first conductor portion 11 of the coil conductor is close to the magnetic core 8 and the length B of the portion where the second conductor portion 12 of the coil conductor is close to the magnetic core 8 is expressed. , A <B is preferable.

<< Eleventh Embodiment >>
FIG. 20 is a front view of an antenna coil provided in the communication terminal device according to the eleventh embodiment. The antenna coil includes a magnetic core 8 having a first main surface MS1 and a second main surface MS2, and a flexible base material 10 on which a coil conductor having a spiral pattern is formed. The coil conductor is located on the first main surface MS1 side of the magnetic core 8 and on the second main surface MS2 side of the magnetic core 8, and from the first main surface MS1 direction or the first main surface MS1 side. It has the 2nd conductor part 12 arrange | positioned in the position (position which does not overlap) different from the 1st conductor part 11, when it planarly views from 2 main surface MS2 direction.

  FIG. 21A, FIG. 21B, and FIG. 21C are front views of a comparative antenna coil. FIG. 21A shows a case where a magnetic core 8 refracted stepwise is used, and the flexible substrate 10 is made flat. FIG. 21B includes a flat magnetic core 8 and a flexible base material 10 refracted stepwise. FIG. 21C includes a flat magnetic core 8 and a flexible base material 10 refracted in a slope shape.

  In the structure of FIG. 21 (A), the magnetic core 8 is refracted stepwise, so that the magnetic flux is effectively interlinked with the coil conductor of the antenna coil, as indicated by the dashed arrow, which has a large amount of leakage flux. Magnetic flux density is low. Moreover, the whole thickness is thick. In the structure of FIG. 21B, although the coupling coefficient with the magnetic flux in the direction along the surface direction of the magnetic core 8 is high, since the coil conductor is bent at an acute angle, the total length of the coil conductor is long and the resistance value is high. High and low Q value. In the structure of FIG. 21C, the total length of the coil conductor is shorter than that of FIG. 21B, but the resistance value is high and the Q value is low.

  On the other hand, according to the antenna coil shown in FIG. 20, since the magnetic core 8 is not refracted at an acute angle, an effective magnetic flux with little leakage magnetic flux can be introduced. Further, the overall length of the coil conductor is short and the resistance value is low. Furthermore, since the magnetic core 8 and the opening surface of the coil conductor intersect at an angle close to 90 degrees, the efficiency is good. That is, when the magnetic flux is linked to the opening surface of the coil at an angle close to 90 degrees, the effective opening surface looks large and a large electromotive force can be generated.

  According to the antenna coil shown in FIG. 20, a high gain is obtained over a wide angle between the antenna coil and the magnetic flux, but a high characteristic can be obtained particularly with respect to a gain in the 45 degree direction.

<< Other embodiments >>
In some embodiments described above, the antenna coil is arranged to face the planar conductor, but the planar conductor is not essential. Further, the antenna coil may be disposed at a position not facing the planar conductor.

  In each of the embodiments described above, the ground electrode of the circuit board or the shield plate disposed on the back surface of the liquid crystal display panel is shown as an example of a planar conductor, but the conductor film or conductor formed on the inner surface of the housing The antenna device can also be configured by treating the foil and further the battery pack as a planar conductor. Further, the planar conductor is not limited to a rectangular conductor, and may be various planar shapes. The planar conductor is not limited to a single layer, and may be composed of a plurality of layers. Furthermore, the planar conductor may have a planar main portion, and may have a bent portion in another portion.

  Further, the present invention can be similarly applied even when the housing of the communication terminal device is a swivel type.

  In each embodiment, an example is shown in which a circuit board having a ground conductor formed on the inner layer is used. However, the present invention can be similarly applied to a circuit board having a ground conductor formed on the surface.

  In some embodiments described above, the antenna coil is disposed inside the housing. However, the antenna coil may be disposed on the outer surface of the housing (the antenna coil is held on the outer surface of the housing). In this case, an input / output terminal of the antenna coil may be drawn into the housing.

AP: Opening CW: Coil conductor opening E: Upper end of the casing (end in the longitudinal direction)
GND: Ground conductor (planar conductor)
MS1 ... first main surface MS2 of magnetic core ... second main surface 8 of magnetic core ... magnetic core 9 ... coil conductors 9a, 9b ... coil conductor 9S ... upper layer coil conductor portion 9U ... lower layer coil conductor portion 10 ... flexible Base material 11 ... 1st conductor part 12 ... 2nd conductor part 20 ... Circuit boards 21-27 ... Antenna coil 31 ... Contact pin 41 ... Liquid crystal display panel 42 ... Key input part 101 ... Antenna apparatus 200 ... Case 200A ... Top side Case 200B ... Bottom side cases 201, 208, 209 ... Communication terminal device 201A ... First communication terminal device 201B ... Second communication terminal device

Claims (6)

A magnetic core having a first main surface and a second main surface, an antenna coil including only one coil conductor wound around the magnetic core and having a single winding axis, and a circuit A communication terminal device comprising: a substrate; and a housing that holds or holds the antenna coil and includes the circuit board therein,
The coil conductor is positioned on the first main surface side of the magnetic core and the second main surface side of the magnetic core, and is in the first main surface direction or the second main surface. A second conductor portion disposed at a position different from the first conductor portion in plan view from the direction,
The housing has two inner surfaces facing each other across the circuit board,
The antenna coil is located between any one of the two inner surfaces and the circuit board, and is arranged such that the second main surface side of the magnetic core faces the outer surface side of the housing ,
The circuit board has a planar conductor;
When the circuit board is viewed in plan, an end of the magnetic core is disposed in a region outside the end of the planar conductor .   In the magnetic core and the coil conductor, the second conductor portion of the coil conductor is closer to the magnetic core than the length of the portion where the first conductor portion of the coil conductor is closer to the magnetic core. The communication terminal device according to claim 1, wherein the length of the portion is configured to be large.   The magnetic core and the coil conductor are configured such that the length of the portion where the first conductor portion of the coil conductor is close to the magnetic core is smaller than the width of the first conductor portion. The communication terminal device according to claim 2.   The communication terminal device according to any one of claims 1 to 3, wherein the antenna coil is disposed such that the first conductor portion of the coil conductor is positioned in the vicinity of an end portion in a longitudinal direction of the casing. . The communication according to any one of claims 1 to 4 , wherein the magnetic core is a composite of magnetic powder and a resin material molded into a sheet shape, or a sintered magnetic body divided into a plurality of pieces. Terminal device. Said magnetic core, said greater than the width of the portion where the width of the portion close to the first conductor portion adjacent to the second conductor portion, the communication terminal device according to any one of claims 1-5.

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