WO2008004326A1 - Bobine d'antenne à monter sur un substrat et dispositif d'antenne équipé d'une telle bobine - Google Patents

Bobine d'antenne à monter sur un substrat et dispositif d'antenne équipé d'une telle bobine Download PDF

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Publication number
WO2008004326A1
WO2008004326A1 PCT/JP2006/326077 JP2006326077W WO2008004326A1 WO 2008004326 A1 WO2008004326 A1 WO 2008004326A1 JP 2006326077 W JP2006326077 W JP 2006326077W WO 2008004326 A1 WO2008004326 A1 WO 2008004326A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnetic core
coil
antenna coil
antenna
circuit board
Prior art date
Application number
PCT/JP2006/326077
Other languages
English (en)
Japanese (ja)
Inventor
Kuniaki Yosui
Hiroyuki Kubo
Hiromitsu Ito
Original Assignee
Murata Manufacturing Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Murata Manufacturing Co., Ltd. filed Critical Murata Manufacturing Co., Ltd.
Publication of WO2008004326A1 publication Critical patent/WO2008004326A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/06—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop with core of ferromagnetic material
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems

Definitions

  • the present invention relates to an antenna coil for mounting on a substrate and an antenna device including the antenna coil.
  • the present invention relates to an antenna coil for mounting on a substrate used in an RFID (Radio Frequency Identification) system that communicates with an external device via an electromagnetic field signal, and an antenna device including the antenna coil.
  • RFID Radio Frequency Identification
  • Patent Document 1 discloses an antenna mounted on a portable electronic device.
  • FIG. 16 is a perspective view showing the structure of the antenna device described in Patent Document 1.
  • FIG. A coil constituting the information communication antenna 102 mounted on the substrate 101 is composed of a plurality of segments 102a and 102b. Each segment also has a magnetic core and a coil force wound around it. The winding direction of the coil of the first segment 102a is left-handed, and the winding direction of the coil of the second segment 102b is right-handed, and the coil of the first segment 102a and the coil of the second segment 102b are connected. Has been.
  • a portion where the coil conductor is not formed (hereinafter referred to as a non-winding portion) is provided between the segments 102a and 102b.
  • a non-winding portion A portion where the coil conductor is not formed.
  • Patent Document 1 JP-A-11-122146
  • the antenna coil 102 has a structure that functions as an antenna when the magnetic flux that has entered the non-winding portion of the coil conductor is guided to the segments 102a and 102b.
  • Non-coiled part force in which case sufficient magnetic flux cannot be captured, and if it is too large, the magnetic flux is not guided to each segment 102a, 102b, so in each case the coil of each segment 102a, 102b Magnetic flux does not pass through the coil axis and electromagnetic induction does not occur. Therefore, each segment 102a, 102b needs to be installed at a fixed interval.
  • an object of the present invention is to provide an antenna coil for mounting on a substrate that is easy to install and does not vary in antenna sensitivity depending on the installation location.
  • Another object of the present invention is to provide an antenna device that is highly sensitive to magnetic flux of external force.
  • an antenna coil for mounting on a substrate has a flat plate-like first magnetic core, and a flat plate-like plate arranged in parallel with the first magnetic core.
  • One coil portion and the conductor are formed around the second magnetic core, and the first coil portion and the coil axis direction coincide with each other, and the winding direction is opposite to that of the first coil portion.
  • a connection conductor that is formed by the conductor and connects the first coil portion and the second coil portion.
  • the antenna coil has a length of 0.7A ⁇ B, where A is the length of the antenna coil in the coil axial direction and B is the distance between the first magnetic core and the second magnetic core. It is effective to satisfy ⁇ 0.5A. [0010] Further, it is preferable that the first magnetic core and the second magnetic core have the same shape.
  • first magnetic core and the second magnetic core are juxtaposed so that the main surfaces face the same direction!
  • a magnetic core is connected to at least one of the end portions of the first magnetic core and the second magnetic core located on both outer sides in the coil axis direction. I want it.
  • the first coil portion and the second coil portion may have the same number of coil turns.
  • connection conductors that connect the first coil portion and the second coil portion are formed.
  • an electrode can be formed on one of the main surfaces of the antenna coil.
  • first magnetic core and the second magnetic core are connected, and the cross-sectional area in the direction orthogonal to the direction in which the first magnetic core and the second magnetic core are aligned is the first. It is smaller than the magnetic core and the second magnetic core, and may comprise a third magnetic core.
  • the circuit board on which the board mounting antenna coil configured as described above is mounted has a length in the coil axis direction of the board mounting antenna coil as X, and the board mounting in the coil axis direction. It is preferable that Y ⁇ X ⁇ 0.8 mm is satisfied, where Y is the distance between two intersection points between the virtual line obtained by projecting the center line of the antenna coil on the circuit board and the outer periphery of the circuit board.
  • the antenna coil for board mounting is mounted on the circuit board with a gap from the circuit board, and the electrode is formed on a surface of the antenna coil facing the circuit board. Better!/,.
  • the present invention has the following effects. [0021] By mounting a flexible substrate on the first magnetic core and the second magnetic core to form a base mounting antenna coil having a first coil portion and a second coil portion, Since the area of the non-winding portion formed between the first coil portion and the second coil portion is kept constant, the antenna coil having a constant antenna sensitivity is not affected by the mounting method on the board. Can be realized.
  • an antenna device on which an antenna coil is mounted a virtual line and a circuit board in which the length in the coil axis direction of the antenna coil is projected on the circuit board and the center line of the magnetic core in the coil axis direction is projected on the circuit board.
  • the antenna coil is mounted so that Y ⁇ X ⁇ 0.8 mm, so that the first magnetic core and the second magnetic core Because the magnetic resistance is reduced at the end of the antenna coil in the direction in which the antennas are aligned, the antenna coil's magnetism collection effect is improved, and an antenna device having high communication sensitivity can be configured.
  • FIG. 1 is a diagram showing a structure of a substrate mounting antenna coil according to a first embodiment.
  • ( ⁇ ) is a perspective view
  • ( ⁇ ) is a plan view.
  • FIG. 2 is a plan view showing a structure of a flexible substrate before mounting on a magnetic core.
  • FIG. 3 is a diagram showing a structure of an antenna device on which a substrate mounting antenna coil according to a second embodiment is mounted.
  • ( ⁇ ) is a perspective view
  • ( ⁇ ) is a plan view.
  • FIG. 2 is a schematic diagram showing a magnetic flux path in a state where the antenna device shown in FIG. 1 is held over a reader / writer for an RFID system.
  • FIG. 4 is a schematic diagram showing a magnetic flux path in a state where the antenna apparatus shown in FIG. 3 is held over a reader / writer for an RFID system.
  • FIG. 5 is a perspective view showing a structure of an antenna coil according to a third embodiment.
  • FIG. 6 is a perspective view showing a structure of an antenna coil according to a third embodiment.
  • FIG. 7 is a perspective view showing a structure of an antenna device according to a fourth embodiment.
  • FIG. 8 is a perspective view showing a structure of an antenna device according to a fourth embodiment.
  • FIG. 9 is a perspective view showing a structure of an antenna device according to a fourth embodiment.
  • FIG. 10 is a perspective view showing a structure of an antenna device according to a fourth embodiment.
  • FIG. 11 is a diagram showing the relationship between the distance between the first magnetic core and the second magnetic core and the coupling coefficient of magnetic flux in the first experiment.
  • FIG. 12 is a diagram showing the relationship between the distance between the first magnetic core and the second magnetic core and the coupling coefficient of magnetic flux in the first experiment.
  • FIG. 13 is a perspective view showing a structure of a substrate mounting antenna coil according to a fifth embodiment.
  • FIG. 14 is a perspective view showing a structure of an antenna device according to a sixth embodiment.
  • FIG. 15 is a perspective view showing a structure of an antenna device according to a sixth embodiment.
  • FIG. 16 is a perspective view showing the structure of the antenna device shown in the conventional example.
  • FIG. 1 is a perspective view and a plan view showing a structure of a substrate mounting antenna coil according to the first embodiment.
  • FIG. 2 is a plan view showing the structure of the flexible substrate before mounting on the magnetic core.
  • the antenna coil 2 includes a first magnetic core 4a, a second magnetic core 4b, a first magnetic core 4a, and a first magnetic core 4a.
  • a flexible substrate 5 is provided around the second magnetic core 4b.
  • the flexible substrate 5 is a single wire. Although shown, it actually has a thickness of about several tens / zm.
  • first magnetic core 4a and the second magnetic core 4b for example, a ferrite having a rectangular shape with a main surface of 8 mm in the horizontal direction and a vertical direction of 10 mm and a thickness of 1.5 mm is used.
  • the lateral sides of the main surfaces of the first and second magnetic cores 4a and 4b are on the same straight line, and the distance between the first magnetic core 4a and the second magnetic core 4b is 24 mm. did.
  • the gap between the first magnetic core 4a and the second magnetic core 4b formed by arranging in this way is referred to as a non-winding portion.
  • a conductor is formed on the surface of the flexible substrate 5, and the first coil portion 2a and the second coil portion are surrounded by the conductor around the first magnetic core 4a and the second magnetic core 4b, respectively.
  • the coil portion 2b is configured.
  • the first coil portion 2a is located on the inner side with a magnetic core exposed by 1 mm at the end located on the outer side of the antenna coil among the lateral ends of the first magnetic core 4a.
  • the edge is wound 6 turns at lmm pitch so that 2mm is exposed.
  • the coil axes of the first coil portion 2a and the second coil portion 2b configured in this way are parallel to the lateral direction of the first magnetic core 4a and the second magnetic core 4b. Further, the winding direction of the first coil portion 2a and the second coil portion 2b is opposite.
  • the first coil portion 2a and the second coil portion 2b are connected by a connection conductor 6, and form a single coil as a whole.
  • FIG. 2 shows the structure of the flexible substrate before being mounted around the magnetic core.
  • the shape of the flexible substrate 5 in plan view is a U shape having an opening 8.
  • the first magnetic core 4a and the second magnetic core 4a are aligned along the shapes of the first magnetic core 4a and the second magnetic core 4b.
  • the center portion of the antenna coil 2 in the direction in which the magnetic cores 4b are arranged is constricted.
  • a protruding portion 9 for connecting to the input / output terminal is formed on the side surface of the flexible substrate 5 facing the side surface where the opening 8 is formed.
  • the material is a polyimide film. Other glass epoxy films and foldable electrical insulating films such as cocoon resin films can also be used.
  • the conductor On the surface of the flexible substrate 5, six conductors are formed on the left and right ends in the short direction through the opening 8.
  • the conductor is shown as a single wire, but the actual width is 0.5mn!
  • the thickness is from 0.05 mm to 0.1 mm.
  • Each guide The body touches the lower end of the flexible substrate 5 but does not touch the upper end in the plan view of FIG.
  • two conductors adjacent to the opening 8 are connected to each other at the upper part of the opening 8 by the connecting conductor 7. Further, the two conductors located at both ends of the flexible substrate are formed up to the end of the protruding portion 9.
  • the conductor can be formed by a screen printing method or the like.
  • the flexible substrate 5 formed as described above has a conductor formed by sandwiching the first magnetic core and the second magnetic core so that the upper end of the conductor and the lower end of the conductor overlap.
  • the overlapping points such as points 11 and 12 are electrically connected by soldering so that the surfaces are bent inward. This forms a conductor as a series of coils.
  • the magnetic flux of the reader / writer force enters the non-winding portion of the antenna coil 2. Therefore, the non-winding portion where no conductor is formed needs to be provided in a sufficient size. However, since the magnetic flux that has entered the non-winding portion must pass through the first magnetic core 4a and the second magnetic core 4b, the magnetic core has a magnetic flux due to the non-winding portion being too large. It must not be difficult to guide. In the first embodiment, since the first magnetic core 4a and the second magnetic core 4b are juxtaposed and mounted on one flexible substrate 5, the first magnetic body The positional relationship between the core 4a and the second magnetic core 4b is kept constant.
  • the antenna coil when the antenna coil is mounted on the circuit board, the antenna having a certain sensitivity that does not deteriorate the antenna sensitivity of the antenna coil by changing the installation location of the antenna coil according to the structure of the circuit board. A coil is realized. Therefore, an antenna coil having a desired antenna sensitivity can be formed regardless of the mounting method on the circuit board.
  • the first magnetic core 4a and the second magnetic body are set such that the distance B between the first magnetic core 4a and the second magnetic core 4b is 24 mm.
  • a coil conductor non-winding portion is provided between the cores 4b.
  • the inner side of the end located outside the antenna coil 2 is inside.
  • the first coil portion 2a and the second coil portion 2b are formed so that the magnetic cores 4a and 4b are exposed in a large amount at the end located at the position.
  • a coil can be formed at the end of the antenna coil 2 where the magnetic flux is concentrated, so that the magnetic flux entering the first magnetic core 4a and the second magnetic core 4b can A structure in which voltage is easily induced is obtained.
  • the flexible substrate 5 does not cover the entire surface of the non-winding portion.
  • the antenna coil 2 has a constricted structure at the center in the coil axis direction. As a result, the area where the antenna coil 2 and the circuit board on which the antenna coil 2 is installed is reduced, so that the installation location of the antenna coil 2 can be easily provided on the circuit board. In addition, since other articles installed on the circuit board may protrude from the constricted portion at the center of the antenna coil 2, the degree of freedom in designing the circuit board 1 on which the antenna coil 2 is mounted is increased.
  • the first magnetic core 4a and the second magnetic core 4b constituting the antenna coil 2 are separated from each other. Compared to the formed antenna coil having the same length as the entire length of the antenna coil 2, it is difficult to break even by an external impact!
  • the flexible substrate 5 is formed with a conductor and is bent with the surface inside, so that no conductor is formed on the surface of the antenna coil 2. Therefore, the conductor is difficult to peel off.
  • the flexible substrate 5 is It is also possible to bend with the surface on which the conductor is formed facing up. Even at that time, since the flexible board has a very thin structure, even if the flexible board is bent and the overlapping points are not bonded to each other, they can be electrically connected by soldering them through the flexible board. Can be connected.
  • the first magnetic core 4a and the second magnetic core 4b have the same shape and the same dimensions, so that the magnetic fluxes entering the respective magnetic cores are equalized. Is possible. Further, since the number of coil turns and the coil axis of the first coil portion 2a and the second coil portion 2b coincide with each other, the voltage induced in each coil portion can be made equal.
  • the first magnetic core 4a and the second magnetic core 4b are rectangular parallelepipeds, but the present invention is not limited to this embodiment. It may be a cylinder. Further, the first magnetic core and the second magnetic core may have different sizes. When the first magnetic core and the second magnetic core having a larger area than the first magnetic core are used, the voltage induced in the second coil portion is induced in the first coil portion. It becomes larger than the voltage. With this configuration, not only the magnetic flux in the direction orthogonal to the coil axis direction of the antenna coil but also the magnetic flux in the direction parallel to the coil axis direction of the antenna coil can be linked.
  • the force of matching the coil axes of the first coil portion 2a and the second coil portion 2b is completely the same, and the antenna coil is not necessary even if it is not.
  • coil A magnetic flux orthogonal to the axial direction can be guided to each coil part.
  • the flexible substrate 5 is provided with the protruding portion 9 for connecting to the input / output terminal.
  • the first coil portion and the second coil portion force are also connected to the input / output terminal. It is not limited to this embodiment.
  • FIG. 3 is a diagram showing a structure of an antenna device on which the board mounting antenna coil according to the second embodiment is mounted.
  • A is a perspective view
  • B is a plan view.
  • FIG. 4 is a schematic diagram showing a magnetic flux path in a state where the antenna device shown in FIG. 3 is held over a reader / writer for an RFID system.
  • an antenna coil 22 is mounted on a circuit board 21.
  • the circuit board 21 has a rectangular main surface having a length in the longitudinal direction of 90 mm and a length in the short direction of 40 mm, for example.
  • the horizontal length of the antenna coil 22 and the short length of the circuit board 21 are the same, so that the horizontal end of the antenna coil 22 and the short end of the circuit board 21 overlap.
  • the antenna coil 22 is mounted on the cable.
  • the antenna coil 22 is fixed to the circuit board 21 using an adhesive.
  • the antenna coil 22 is formed in the same manner as in the first embodiment, description thereof is omitted here, but in the second embodiment, a protruding portion for connecting to the input / output terminal is not provided, and a flexible substrate is provided.
  • the end of the conductor formed on the circuit board and the end of the conductor formed on the circuit board are connected by soldering.
  • the main surface of the circuit board 21 and the main surfaces of the first and second magnetic cores 24a and 24b are opposed to the circuit board 21, and the horizontal sides of the first and second magnetic cores 24a and 24b are opposed to each other.
  • ⁇ in the figure indicates the magnetic flux from the reader / writer.
  • the antenna device When the antenna device is normally mounted on a mobile terminal, the main surface of the mobile device and the circuit board of the antenna device are The antenna device is installed so as to be parallel. In addition, mobile terminal users hold the main surface of the mobile terminal parallel to the main surface of the reader / writer.
  • Fig. 4 shows the magnetic flux path from the reader / writer 20 and the cross-sectional structure of the antenna device when this type of usage is adopted.
  • the magnetic flux ⁇ from the reader / writer 20 is generated by the coil conductor provided between the first magnetic core 24a and the second magnetic core 24b of the antenna coil 22. Enter the turning section.
  • the entered magnetic flux is blocked by the circuit board 21 existing behind the antenna coil 22, and the traveling direction is bent by approximately 90 °. Then, it passes through the first magnetic core 24a and the second magnetic core 24b. Because the magnetic flux ⁇ from the reader / writer takes such a path, the magnetic flux ⁇ from the reader / writer 20 is obtained even if the coil axis of the antenna coil 22 and the magnetic flux ⁇ from the reader / writer 20 are orthogonal to each other. Can be captured and linked to cause electromagnetic induction.
  • the first coil portion 22a and the second coil portion 22b are formed around the first magnetic core 24a and the second magnetic core 24b, respectively. The magnetic flux passes through the coil axis. Therefore, a voltage is easily induced by the magnetic flux passing through the first magnetic core 24a and the second magnetic core 24b.
  • the magnetic flux ⁇ of the reader / writer force passes through the first magnetic core 24a and the second magnetic core 24b, whereby the coils of the first coil portion 22a and the second coil portion 22b.
  • Magnetic flux passes through the shaft, and voltage is generated at each coil. Since the magnetic flux enters between the first coil portion 22a and the second coil portion 22b, the magnetic flux in the opposite direction passes through the coil axis of each coil portion. However, since the coil winding directions of the first coil portion 22a and the second coil portion 22b are opposite, a voltage is generated in the same direction, and the first coil portion 22a and the second coil portion 22b Even if connected by connecting conductor 27, the voltage will not be cancelled.
  • the antenna device 23 of the present embodiment has a length in the short direction on the main surface of the circuit board 21 as X and a length in the coil axis direction of the antenna coil 22.
  • the antenna coil 22 is installed on the circuit board 21 so as to satisfy X ⁇ Y ⁇ 0.8 mm, so that the end of the antenna coil 22 in the coil axial direction is aligned with the end of the circuit board 21.
  • the antenna coil As the magnetic resistance at the end of the coil axis direction of the antenna coil 22 can be reduced, the antenna coil As a result, the antenna magnetic force can be improved and the antenna device can have high communication sensitivity.
  • the second embodiment satisfies the above inequality. Therefore, it is possible to link well with the magnetic flux of the reader / writer force.
  • the antenna coil 22 is installed so that the end of the antenna coil 22 in the coil axis direction and the end of the circuit board 21 in the short direction overlap each other.
  • the two intersections of the virtual line projected on the circuit board 21 from the center line of the antenna coil 22 in the coil axis direction and the end surface of the antenna coil 22 in the coil axis direction are xl, x2, respectively Of the two intersections between the line and the outer periphery of the circuit board 21, when the intersection near xl, yl, and the intersection near x2, is y2, the distance between xl and y2 is equal to the distance between x2 and y2.
  • the magnetic resistance at the end of the antenna coil 22 in the coil axis direction can be made equal, and the magnetic flux passing through the first magnetic core 24a and the second magnetic core 24b can be made equal.
  • the antenna coil 22 and the circuit board 21 are fixed with an adhesive, but the method of mounting the antenna coil on the circuit board is limited to this. Well then.
  • the magnetic core is connected to the end portions of the first magnetic core and the second magnetic core located on both outer sides in the coil axial direction.
  • the configuration of the antenna coil shall be configured in accordance with the first embodiment. However, there are no protrusions to connect to the input / output terminals.
  • the magnetic cores 88 a and 88 b extending in the direction orthogonal to the coil axis direction of the antenna coil 82 are formed at both ends of the first magnetic core 84 a and the second magnetic core 84 b.
  • the magnetic cores 88a and 88b provided continuously have a length of 10 mm in the vertical direction, a length of 1.5 mm in the horizontal direction, and a length of 2.3 mm in the thickness direction.
  • the magnetic core 88a is bonded to the end surface of the first magnetic core 84a in the coil axis direction.
  • the vertical side of the magnetic core 88a overlaps the vertical side of the first magnetic core 84a.
  • the horizontal side of the magnetic core 88b is arranged so as to be aligned with the horizontal side of the first magnetic core 84a.
  • the magnetic core 88b is bonded to the end surface of the second magnetic core 84b.
  • the antenna coil 82 according to the first embodiment when mounted on a rectangular parallelepiped circuit board, the antenna coil can be formed along the shape of the circuit board. And an antenna device comprising a circuit board can be reduced in size.
  • FIG. 6 shows a configuration of the antenna coil 92 in which arc-shaped magnetic cores 98a and 98b are continuously provided on the end surface of the antenna coil 92 in the coil axial direction.
  • the end surface of the magnetic core 98a connected to the first magnetic core 94a has the same size and shape as the end surface in the coil axis direction of the first magnetic core, and is bonded so that they overlap completely. Has been.
  • the magnetic core 98b is bonded to the end surface of the second magnetic core 94b.
  • the magnetic flux that has entered the inner side surfaces of the first magnetic core and the second magnetic core passes through the first coil portion and the second coil portion. Further, the light is radiated from the side surface to the space through the magnetic core connected to the first magnetic core and the second magnetic core.
  • the magnetic core is formed at the end of the antenna coil, and the side surface of the magnetic core from which the magnetic flux is radiated into the space is widened. Becomes smaller. As a result, the magnetic flux that enters the antenna coil, passes through the first coil portion and the second coil portion, and causes electromagnetic induction increases, thereby enabling more sensitive communication.
  • the above effects are not limited to the first and second embodiments described above.
  • the ends of the first magnetic core and the second magnetic core are located on both outer sides in the coil axis direction of the antenna coil. It suffices if a magnetic core is connected to the part.
  • the continuous arrangement is not only the structure in which the magnetic core is added to the end of the first magnetic core and the second magnetic core, but also the first magnetic core, This includes a structure formed integrally with the second magnetic core, and a structure formed by bending the first magnetic core and the second magnetic core.
  • the first magnetic core and the second magnetic core are connected by the third magnetic core.
  • the third magnetic core is the first magnetic core with respect to the cross-sectional area in the direction parallel to the longitudinal direction of the first magnetic core and the second magnetic core. And smaller than the second magnetic core.
  • the antenna coil and the circuit board are configured according to the first embodiment and the second embodiment. Therefore, since the antenna coil according to this embodiment is configured by mounting a flexible substrate on the first magnetic core and the second magnetic core, the first coil portion and the second coil portion The area of the non-winding part formed therebetween is kept constant.
  • the antenna device includes two antenna lines: an imaginary line obtained by projecting the length of the antenna coil in the coil axis direction X, the center line of the magnetic core in the coil axis direction onto the circuit board, and the outer periphery of the circuit board. Since the antenna coil is mounted on the circuit board so that Y ⁇ X ⁇ 0.8 mm, where Y is the distance between the intersections, the first magnetic core and the second magnetic core At the ends of the antenna coils in the line-up direction, the magnetic resistance is reduced, the magnetic flux collection effect of the antenna coils is improved, and the antenna device functions as a high communication sensitivity.
  • the thickness of the third magnetic core 34c is thinner than the thickness of the first magnetic core 34a and the second magnetic core 34b!
  • the structure of the antenna device 33 using the antenna coil 32 is shown in FIG. It is shown.
  • the main surface of each magnetic core 34a, 34b, 34c facing the circuit board 31 is the first main surface and the main surface opposite to the first main surface is the second main surface
  • the first, second, The second main surfaces of the third magnetic cores 34a, 34b, 34c are located on the same plane.
  • the first main surface of the first and second magnetic cores 34a and 34b is a force located on the same surface.
  • the first main surface of the third magnetic core 34c is located on a different surface, and The third magnetic core 34c is thin As a result, a gap is generated between the third magnetic core 34c and the circuit board 31. With this configuration, a gap is formed between the third magnetic core 34c and the circuit board 31, and the space generated thereby can be used effectively.
  • FIG. 8 shows an antenna using an antenna coil 42 in which the longitudinal length of the third magnetic core 44c is shorter than the longitudinal length of the first magnetic core 44a and the second magnetic core 44b.
  • the structure of device 43 is shown.
  • the first, second, and third magnetic cores 44a, 44b, and 44c are all located on the same plane among the lateral side surfaces.
  • the other side surfaces of the first and second magnetic cores 44a and 44b are located on the same surface, while the other side surface of the third magnetic core 44c is located on a different surface.
  • the area where the antenna coil 42 and the circuit board 41 are in contact with each other is reduced, so that the antenna coil 42 can be easily installed on the circuit board 41.
  • the degree of freedom in designing the circuit board 41 on which the antenna coil 42 is mounted increase.
  • FIG. 9 shows an antenna using an antenna coil 52 in which the longitudinal length of the third magnetic core 54c is shorter than the longitudinal length of the first magnetic core 54a and the second magnetic core 54b.
  • the structure of device 53 is shown.
  • the third magnetic core 54c is located on a side surface different from the side surfaces of the first magnetic core 54a and the second magnetic core 54b on both lateral sides.
  • the central portion in the horizontal direction of the antenna coil 52 is constricted. Structure.
  • the area of contact between the antenna coil 52 and the circuit board 51 is reduced, so that the installation location of the antenna coil 52 can be easily provided on the circuit board 51.
  • other parts installed on the circuit board 51 may protrude from the constricted portion of the central part of the antenna coil 52, so that the design flexibility of the circuit board 51 on which the antenna coil 52 is mounted is increased. Increase. [Example 4]
  • FIG. 10 shows the structure of the antenna coil 62 including the third magnetic core 64c having a smaller thickness and a shorter lateral length than the first magnetic core 64a and the second magnetic core 64b. It is shown. With this configuration, a gap is formed between the third magnetic core 64c and the circuit board 61, and the generated space can be used effectively. Further, the antenna coil 62 has a constricted central portion in the horizontal direction. As a result, the area where the antenna coil 62 and the circuit board 61 are in contact with each other is reduced, so that the installation location of the antenna coil 62 is provided on the circuit board 61. Since other components installed on the circuit board 61 may protrude, the degree of freedom in designing the circuit board 61 on which the antenna coil 62 is mounted increases.
  • the third magnetic core is formed and the magnetic core is provided in the non-winding portion, so that the magnetic flux collecting effect of the antenna coil is enhanced. Therefore, the antenna sensitivity increases.
  • the third magnetic core is more than the first magnetic core and the second magnetic core. Since it is small, the area where the third magnetic core is in contact with the circuit board can be reduced, and the antenna coil can be easily mounted on the circuit board.
  • the first magnetic core and the third magnetic core, and the second magnetic core and the third magnetic core are bonded. However, they are bonded. If it is magnetically connected, it is possible to enhance the magnetic flux collection effect of the antenna coil.
  • the first magnetic core, the second magnetic core, and the third magnetic core can be integrally formed.
  • FIG. 11 and FIG. 12 are diagrams showing a change in the coupling coefficient between the antenna device and the magnetic flux of the reader / writer force when the length of the non-winding portion is changed.
  • Fig. 11 shows the results of the first experiment
  • Fig. 12 shows the results of the second experiment.
  • h indicates the ratio of the distance between the first magnetic core and the second magnetic core to the length of the antenna coil in the coil axis direction.
  • a circuit board having a main surface of 40 mm in the horizontal direction and 90 mm in the vertical direction The antenna coil is 40mm in the horizontal direction, 10mm in the vertical direction, and lmm thick.
  • the configuration of the antenna coil excluding the length dimension is the same as that of the first embodiment.
  • the antenna coil is composed of a first coil part and a second coil part so that the magnetic core is exposed by 1 mm at both ends, and the coil conductor in each coil part is formed with 7 turns at intervals of 0.2 mm. .
  • ferrite of ⁇ : 70, tan 6: 0.01 is used. Under such conditions, the distance between the first magnetic core and the second magnetic core was changed.
  • the antenna core including the third magnetic core which is 1Z4 of the thickness of the first and second magnetic cores.
  • the distance between the antenna coil and the reader / writer was set to 100 mm, and the coupling coefficient obtained was measured.
  • Figure 11 shows the experimental results for each pattern.
  • a circuit board having a main surface of 45 mm in the horizontal direction and 90 mm in the vertical direction and an antenna coil having a width of 45 mm, 10 mm in the vertical direction, and a thickness of 1 mm are used.
  • the configuration of the antenna coil excluding the length dimension is the same as in the first embodiment.
  • the antenna coil has a first coil portion and a second coil portion so that the magnetic core is exposed by 1 mm at both ends, and the coil conductor in each coil portion is formed with 7 turns at intervals of 0.22 mm.
  • the same ferrite as in the first experiment is used.
  • the distance between the antenna coil and the reader / writer was set to 100 mm in three patterns, and the degree of coupling coefficient obtained was measured.
  • Figure 12 shows the experimental results for each turn.
  • the length of the antenna coil in the coil axis direction is A
  • the distance between the first magnetic core and the second magnetic core is B.
  • the volume of the antenna coil can be significantly reduced.
  • FIG. 13 is a perspective view showing a configuration of an antenna coil 72 in which five connection conductors 77 are formed.
  • the first coil part 72a and the second coil part 72b are connected by five connection conductors 77a, 77b, 77c, 77d, 77e formed on the flexible substrate 75, and each connection conductor is formed at equal intervals. Yes.
  • the structure of the antenna coil excluding the connecting conductor is configured according to the first embodiment. If one of the five connecting conductors is cut by a laser, etc., except for one of the connecting conductors, the current path coming from the first coil part or the second coil part is determined as one.
  • the length of the conductor constituting each coil part of the antenna coil is changed by the nose, and when the connection conductors 77b, 77c, 77d, 77e are cut and the current path is changed to the connection conductor 77a, the length of the conductor Is the shortest, and conversely, when the connection conductors 77a, 77b, 77c, 77d are cut and the current path is changed to the connection conductor 77e, the length becomes the longest.
  • Table 1 shows the nose and inductance values of the antenna coil 72 according to the fifth embodiment.
  • FIG. 6 is a diagram showing the rate of change of the inductance value of each path with reference to the inductance value when the connection conductor 77a is selected as the path and the connection conductor 77a.
  • the inductance value increases as the length of the conductors constituting each coil increases as the path is changed from the connecting conductors 77a to 77e. Compared with the case where the path 77a is selected. If the path 77e is selected, an inductance value of 11.41% can be obtained. That is, the inductance value can be changed within a range of about 11% depending on which of the five connection conductors 77a, 77b, 77c, 77d, and 77e is selected as a path.
  • the resonance frequency of the resonance circuit including the antenna coil and the capacitor can be adjusted.
  • power is induced by the change of the magnetic flux passing through the coil section regardless of the resonance frequency, but a particularly large voltage is induced when the resonance frequency and the frequency of the entering magnetic flux are inconsistent. Is done. Therefore, the voltage generated by adjusting the resonance frequency of the resonance circuit to a desired value is increased, and the communication sensitivity of the antenna is improved.
  • the antenna coil 72 is formed as shown in FIG. 13, since the inductance can be selected after the antenna coil is manufactured, the communication sensitivity of the antenna can be improved very easily.
  • connection conductors 77a, 77b, 77c, 77d, and 77e are formed in the non-winding portion where the magnetic flux from the reader / writer enters. Although these connecting conductors can prevent the magnetic flux from entering, the ratio of the portion where the connecting conductor is formed to the area of the non-winding portion is very small, so the magnetic flux is considered to enter smoothly.
  • the antenna device is configured by mounting a board mounting antenna coil with a gap on a circuit board. Also, the antenna coil for board mounting It is also peculiar to the present embodiment that electrodes are formed on the surface facing the circuit board. Other configurations that are not described in the following examples conform to the first embodiment. However, the protrusion for connecting to the input / output terminal is not formed.
  • FIG. 14 is a diagram illustrating the structure of the antenna device according to the first embodiment.
  • (A) is a plan view.
  • (B) is a cross-sectional view taken along the line AA in (A).
  • the antenna coil 102 is mounted on the circuit board 101 with a gap.
  • electrodes 109 are formed on the surfaces of the first magnetic core 104a and the second magnetic core 104b facing the circuit board 101.
  • the main surface of the electrode 109 and the main surfaces of the first and second magnetic cores 104a and 104b have the same shape and the same dimensions.
  • the main surface of the electrode 109 and the first and second magnetic cores The main surfaces of 104a and 104b completely overlap.
  • the circuit board 101 has, for example, a rectangular main surface having a length of 90 mm in the longitudinal direction and a length of 50 mm in the short direction.
  • the antenna coil 102 is arranged so that the horizontal direction of the antenna coil 102 and the longitudinal direction of the circuit board 101 are parallel.
  • the gap between the circuit board 101 and the antenna coil 102 is lmm.
  • the magnetic flux entering the non-winding portion of the coil conductor provided between the first magnetic core 104a and the second magnetic core 104b of the antenna coil 102 is The path is blocked by the conductive circuit board 101 that exists behind the film 102 and changes the direction of travel, and enters the first magnetic core 104a and the second magnetic core 104b.
  • the magnetic flux force that has entered the first magnetic core 104a and the second magnetic core 104b is radiated.
  • the voltage is very small.
  • the first magnetic Since the electrodes 109 are formed on the surfaces of the active material core 104a and the second magnetic material core 104b facing the circuit board 101, radiation of magnetic flux can be prevented. Therefore, a voltage can be generated in the coil that is linked with the magnetic flux from the direction perpendicular to the main surface of the antenna coil 102 and also has the force as the first coil portion 102a and the second coil portion 102b.
  • FIG. 15 is a diagram illustrating the structure of the antenna device according to the second embodiment.
  • (A) is a plan view.
  • (B) is a sectional view of the BB portion in (A).
  • antenna coil 112 is mounted on circuit board 111 with a gap.
  • the antenna coil 112 extends on both end surfaces of the first magnetic core 114a and the second magnetic core 114b located on both outer sides in the coil axis direction.
  • the magnetic cores 118a and 118b extend in a direction perpendicular to the coil axis direction.
  • Is a structure in which The method of forming the first and second magnetic cores and the flexible substrate is in accordance with the first embodiment.
  • the outer end of the first magnetic core and the outer end of the second magnetic core The distance between is 45mm. However, no protrusions for connecting to the input / output terminals are formed.
  • the magnetic cores 118a and 118b have a length of 10 mm in the vertical direction, a length of 1 mm in the horizontal direction, and a length of 3.5 mm in the thickness direction.
  • the magnetic core 118a is bonded to the end surface of the first magnetic core 114a in the coil axis direction.
  • the longitudinal side of the magnetic core 118a overlaps the longitudinal side of the first magnetic core 114a
  • the lateral side of the magnetic core 118b is the lateral side of the first magnetic core 114a.
  • the magnetic core 118b is bonded to the end surface of the second magnetic core 114b.
  • the electrode 119 is formed on the surface of the first magnetic core 114a and the second magnetic core 114b facing the circuit board 111, and covers the entire surface of each magnetic core 114a, 114b.
  • the circuit board 111 is made of copper having a longitudinal direction of 90 mm, a lateral direction of 45 mm, and a thickness of 1 mm.
  • the antenna coil 112 is arranged so that the lateral direction of the antenna coil 112 and the longitudinal direction of the circuit board 111 are parallel to each other.
  • the gap between the circuit board 111 and the antenna coil 112 is 1 mm.
  • the magnetic flux that has entered the non-winding portion of the antenna coil 112 passes through the first coil portion 112a and the second coil portion 112b. Since the first magnetic core 114a and the second magnetic core 114b are formed with electrodes, even if a gap is provided between the antenna coil 112 and the circuit board 111, the first coil portion There is no radiation without passing through 112a and the second coil part 112b.
  • the magnetic flux that has passed through the first and second coil portions 112a and 112b enters the magnetic cores 118a and 118b that are connected to each other, and is radiated from the side forces of the magnetic cores 118a and 118b.
  • the magnetic core is formed at the end of the antenna coil 112
  • the magnetic resistance at the end is lowered. Therefore, the magnetic flux passing through the first coil part 112a and the second coil part 112b increases, and the voltage induced thereby increases. Therefore, communication with higher sensitivity is possible.
  • the electrodes are formed on the surface of the antenna coil that faces the circuit board, so that the reader / writer can be connected even if a gap is provided between the antenna coil and the circuit board.
  • High-sensitivity communication can be realized. Therefore, when an antenna device including an antenna coil and a circuit board is mounted on a portable terminal, it is possible to provide a gap between the antenna coil and the circuit board by bonding the antenna coil to the casing of the portable terminal.
  • the antenna device is mounted on a two-fold portable terminal equipped with a main casing and a sub casing, the mobile terminal is folded by installing a circuit board in the main casing and an antenna coil in the sub casing.
  • the circuit board can be formed behind the antenna coil when viewed from the side of the reader / writer.
  • mounting the antenna coil on which the electrode is formed on the circuit board with a gap increases the degree of freedom in design with respect to the installation location of the antenna device on the portable terminal.

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Details Of Aerials (AREA)
  • Support Of Aerials (AREA)

Abstract

L'invention concerne une bobine d'antenne (2) possédant un premier noyau magnétique (4a), un second noyau magnétique (4b) et un substrat souple (5). Un conducteur de bobine est formé sur la surface du substrat souple (5). Ce substrat souple (5) est enveloppé autour du premier (4a) et du second noyau magnétique (4b), ce qui forme une première section de bobine (2a) autour du premier noyau magnétique (4a), et une seconde section de bobine (2b) autour du second noyau magnétique (4b). La seconde section de bobine (2b) est enroulée dans le sens opposé à celui de la première section de bobine (2a). La première section de bobine (2a) et la seconde section de bobine (2b) sont interconnectées, et ces deux sections de bobines forment une bobine en un tout.
PCT/JP2006/326077 2006-07-07 2006-12-27 Bobine d'antenne à monter sur un substrat et dispositif d'antenne équipé d'une telle bobine WO2008004326A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2006187484 2006-07-07
JP2006-187484 2006-07-07
JP2006198253 2006-07-20
JP2006-198253 2006-07-20

Publications (1)

Publication Number Publication Date
WO2008004326A1 true WO2008004326A1 (fr) 2008-01-10

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PCT/JP2006/326077 WO2008004326A1 (fr) 2006-07-07 2006-12-27 Bobine d'antenne à monter sur un substrat et dispositif d'antenne équipé d'une telle bobine

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TW (1) TW200805794A (fr)
WO (1) WO2008004326A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2120290A1 (fr) * 2007-03-09 2009-11-18 Murata Manufacturing Co. Ltd. Bobine d'antenne pour un montage sur une carte de circuits imprimés

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08204432A (ja) * 1995-01-27 1996-08-09 Citizen Watch Co Ltd 携帯型電子機器のアンテナ構造
JPH11122146A (ja) * 1997-10-16 1999-04-30 Kokusai Electric Co Ltd Ｉｃカードシステム
JP2001034726A (ja) * 1999-07-22 2001-02-09 Denso Corp Ｉｄタグ
JP2002207981A (ja) * 2001-01-09 2002-07-26 Denso Corp Ｉｄタグ
JP2003318634A (ja) * 2002-04-24 2003-11-07 Smart Card:Kk 非接触式センサコイル
JP2005277524A (ja) * 2004-03-23 2005-10-06 Matsushita Electric Ind Co Ltd 磁性体アンテナ
JP2006050522A (ja) * 2003-11-27 2006-02-16 Hitachi Metals Ltd アンテナ及びこれを用いた電波時計、キーレスエントリーシステム、ｒｆｉｄシステム
JP3121577U (ja) * 2006-03-02 2006-05-18 株式会社スマート 偏心磁性体コイルシステム

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08204432A (ja) * 1995-01-27 1996-08-09 Citizen Watch Co Ltd 携帯型電子機器のアンテナ構造
JPH11122146A (ja) * 1997-10-16 1999-04-30 Kokusai Electric Co Ltd Ｉｃカードシステム
JP2001034726A (ja) * 1999-07-22 2001-02-09 Denso Corp Ｉｄタグ
JP2002207981A (ja) * 2001-01-09 2002-07-26 Denso Corp Ｉｄタグ
JP2003318634A (ja) * 2002-04-24 2003-11-07 Smart Card:Kk 非接触式センサコイル
JP2006050522A (ja) * 2003-11-27 2006-02-16 Hitachi Metals Ltd アンテナ及びこれを用いた電波時計、キーレスエントリーシステム、ｒｆｉｄシステム
JP2005277524A (ja) * 2004-03-23 2005-10-06 Matsushita Electric Ind Co Ltd 磁性体アンテナ
JP3121577U (ja) * 2006-03-02 2006-05-18 株式会社スマート 偏心磁性体コイルシステム

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2120290A1 (fr) * 2007-03-09 2009-11-18 Murata Manufacturing Co. Ltd. Bobine d'antenne pour un montage sur une carte de circuits imprimés
EP2120290A4 (fr) * 2007-03-09 2011-05-11 Murata Manufacturing Co Bobine d'antenne pour un montage sur une carte de circuits imprimés
US8179332B2 (en) 2007-03-09 2012-05-15 Murata Manufacturing Co., Ltd. Antenna coil and antenna device

Also Published As

Publication number Publication date
TWI347035B (fr) 2011-08-11
TW200805794A (en) 2008-01-16

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