JP2005269389A - Antenna coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna coil of high connection reliability of a lead terminal whose thickness and height can be reduced. <P>SOLUTION: A notch 7 is formed on a side surface 2a of a substrate 2, of an antenna coil 1, arranged along coils 11-13. An electrode 8 is provided on the end face inside the notch 7. A lead terminal L of the coils 11-13 is extended from the end face inside the notch 7 of the substrate 2 while connected to the electrode 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antenna coil used for a keyless entry system of an automobile, for example.

Conventionally, as an electronic key system for a vehicle, an IC coil (portable transmitter / receiver) as an electronic key is provided with an antenna coil, and a vehicle card reader (external transmitter / receiver) is electromagnetically coupled to the IC card antenna coil. When an interrogation signal is transmitted from the antenna coil of the card reader on the vehicle side via the air and the interrogation coil receives this interrogation signal, the IC card receives the specific signal from the antenna coil as a response signal. The card reader reads the ID code transmitted from the IC card and compares them with the ID code stored in advance on the vehicle side. A technique for unlocking or starting an engine is known (for example, patent document) Reference.).
In addition, as a lead terminal connection structure of an antenna coil, for example, in Patent Documents 2 and 3, it is formed by a protruding portion of a core (ferrite core), a metal terminal plate attached to the upper and lower surfaces of a coil winding frame, or the like. The structure which connects the lead terminal of a coil through the made electrode part is described. There is also a method of bonding a coil to a metal lead frame and connecting a lead terminal of the coil to one end of the lead frame by soldering or the like.
JP-A-8-274682 JP 2003-92509 A JP 2004-32754 A

  In the case of a conventional lead terminal connection structure used for an antenna coil, since the terminals are provided on the upper and lower surfaces of the frame or the like, there is a problem that the thickness of the antenna coil is increased and it is difficult to reduce the thickness and height. In addition, since the connecting portion between the lead terminal and the electrode protrudes from the frame, there is a risk of disconnection or damage upon impact.

This invention is made | formed in view of the said situation, and makes it a subject to provide the antenna coil with high connection reliability of a lead terminal and which can implement | achieve thickness reduction and low profile.
This is the issue.

In order to solve the above-mentioned problem, the present invention provides a notch formed on a side surface of a substrate disposed along a coil, an electrode is provided on an inner end surface of the notch, and a lead terminal of the coil is notched on the notch of the substrate. An antenna coil is provided that extends to the inner end surface of the antenna coil and is connected to the electrode.
In the antenna coil, as the substrate, a printed wiring board having a half-cut through hole as a notch having an electrode on the inner end face can be used.

According to the present invention, since the lead terminal of the coil is accommodated and connected in the cutout formed on the side surface of the substrate, the lead terminal, the electrode, and the electrode are hardly protruded above and below the antenna coil. Can be connected. Therefore, the thickness of the antenna coil is reduced, and it becomes easy to realize a reduction in thickness and height of the antenna coil.
Further, since the connection portion between the lead terminal and the electrode is accommodated in the notch, the connection reliability of the lead terminal can be improved.

The present invention will be described below with reference to the drawings based on the best mode.
As shown in FIGS. 1A, 1B, etc., the antenna coil 1 is disposed so as to circulate along a substrate 2 having an opening 3 formed in the center and the periphery of the opening 3. Z-axis coil 13, X-axis coil 11 and Y-axis coil 12, XY coil unit 10 inserted into opening 3, and XY coil unit 10 and Z-axis coil 13 on the opposite side of substrate 2 And a cover 4 for covering from the above.

As shown in FIGS. 2A and 2B, the XY coil unit 10 includes an X-axis coil 11 and a Y-axis coil 12 wound around a substantially square core 15 by winding winding wires in directions orthogonal to each other. It is the structure which formed.
Here, a solid flat core is used as the core 15. As the material of the core 15, various soft magnetic materials such as ferrite and amorphous alloy can be adopted.
The Z-axis coil 13 is an air-core coil formed by winding a winding wire in a circular shape, and is bonded to one surface of the substrate 2.

  The substrate 2 and the cover 4 are integrated so as to face each other, thereby obtaining an internal space 6 for accommodating the XY coil unit 10 and the Z-axis coil 13 therein. That is, the substrate 2 and the cover 4 constitute a case that houses the coils 11 to 13 and the core 15.

As the board | substrate 2, the printed wiring board (for example, glass epoxy board | substrates, such as FR4) in which the opening part 3 was formed in the center part can be used.
Although it does not specifically limit as the cover 4, For example, a plastic molded article etc. can be used. In the center of the cover 4, an opening 5 is formed at a position facing the opening 3 of the substrate 2.

The openings 3 and 5 penetrate a square shape substantially corresponding to the planar shape of the core 15 and communicate with the internal space 6. As a result, the X-axis coil 11 and the Y-axis coil 12 are allowed to protrude into the openings 3 and 5. Thereby, the antenna coil 1 can be further reduced in thickness.
When the Z-axis coil 13 is accommodated in the internal space 6, the hollow portion 14 of the Z-axis coil 13 communicates with the openings 3 and 5 so that the XY coil unit 10 is accommodated therein. It has become.

At the four corners of the openings 3 and 5, pressing parts 3a and 5a are formed to project toward the centers of the openings 3 and 5, respectively. The pressing portions 3a and 5a protrude to a position where they overlap with the corners of the core 15 in a plan view as shown in FIG.
As a result, the substrate 2 and the cover 4 are prevented from falling off from the internal space 6 of the XY coil unit 10 by sandwiching the core 15 between the pressing portions 3a and 5a of the substrate 2 and the cover 4, respectively. The coil unit 10 can be stably accommodated in the internal space 6.

  Thus, by accommodating the XY coil unit 10 in the hollow portion 14 of the Z-axis coil 13, the X-axis coil 11, the Y-axis coil 12, and the Z-axis coil 13 are arranged in a direction perpendicular to each other. , It functions as a three-axis antenna coil capable of receiving any three-dimensional direction.

  A plurality of notches 7 are formed on the side surface 2 a of the substrate 2. The shape of the notch 7 is semicircular here, but is not particularly limited in the present invention, and various shapes such as a V-shape (triangle shape), a U-shape, and a quadrilateral shape can be employed. Electrodes 8 are respectively provided on the inner end surfaces of these notches 7 by metal plating such as copper.

As shown in FIG. 3, the lead terminals L of the coils 11 to 13 extend to the inner end face of the notch 7 and are connected to the electrode 8 formed in the notch 7. Each lead terminal L and the electrode 8 can be connected by, for example, spot welding. Examples of the welding method include laser welding and resistance welding. As this notch 7, for example, a half-cut through hole formed in the printed wiring board 2 can be used.
The substrate 2 has land portions 9 formed on the periphery of the notches 7. The electrode 8 in the notch 7 is electrically connected by connection wirings 16c, 16x, 16y, 16z formed so as to communicate between the land portions 9.

Here, as shown to Fig.1 (a), the lead terminal L which is the both ends of the three coils 11-13 of X, Y, and Z is connected to the electrode 8 in the notch 7, respectively. Further, the substrate 2 is provided with four notches 7 having electrodes 8 for connection to an external circuit in addition to the six electrodes 8 for connection to the coils 11 to 13 described above.
In the following description, in order to distinguish each lead terminal L, one end of the X-axis coil 11 is denoted by reference numeral 11a, the other end of the X-axis coil 11 is denoted by reference numeral 11b, and one end of the Y-axis coil 12 is denoted by reference numeral 12a. The other end of the coil 12 may be distinguished by reference numeral 12b, one end of the Z-axis coil 13 by reference numeral 13a, and the other end of the Z-axis coil 13 by reference numeral 13b.

  One of the connection wirings 16c, 16x, 16y, and 16z 16c connects the four electrodes 8 to each other. Three of these four electrodes 8 are connected to one end 11a, 12a, 13a of each coil 11, 12, 13 respectively. An external circuit can be connected to the remaining empty electrode 8. As described above, the four terminals 8 connected to each other via the connection wiring 16c constitute a common terminal 17c in which the ends 11a to 13a of the three coils 11 to 13 are connected in common.

  Further, the other connection wirings 16x, 16y, and 16z each connect two electrodes 8 to each other. One of the two electrodes 8 connected via the connection wirings 16x, 16y, and 16z has an other side opposite to the side connected to the common terminal 17c of each of the coils 11, 12, and 13, respectively. The ends 11b, 12b, and 13b are connected. An external circuit can be connected to the other electrode 8. In this way, the individual electrodes 17x, 17y, and 17z of the coils are configured by the two electrodes 8 that are connected to each other via the connection wirings 16x, 16y, and 16z.

  When this antenna coil 1 is used as an antenna for a data transmission / reception card of a portable electronic key, the antenna coil 1 is embedded in an IC card together with a control unit that also serves as a storage unit for storing a vehicle-specific ID code signal and the like. Used.

An electronic key system for a vehicle using an antenna for a data transmission / reception card is provided with a three-axis type antenna coil 1 having an X-axis coil, a Y-axis coil, and a Z-axis coil on an IC card as an electronic key. An antenna coil that is electromagnetically coupled to the IC card data transmission / reception card antenna is provided in the card reader (external transceiver) on the side, and when the vehicle and the IC card are within a predetermined distance, The interrogation signal is transmitted from the antenna coil as an electromagnetic induction signal that is an aerial propagation signal.
At this time, power for driving the IC card is also sent, and when this interrogation signal is received by the antenna for the triaxial data transmission / reception card of the IC card, the response of the IC card is received as a response signal from the antenna for the triaxial data transmission / reception card. The vehicle-specific ID code signal stored in the control unit is transmitted as an electromagnetic induction signal that is an aerial propagation signal.
The card reader reads the ID code transmitted from the IC card, compares it with the ID code stored in advance on the vehicle side, and if they match, performs a door lock, unlock or engine start. Yes.

Thus, since the lead terminal of the coil is designed to be connected to the electrode provided in the notch formed on the side surface of the substrate, the electrode and the lead terminal hardly protrude above and below the antenna coil, The lead terminal and the electrode can be connected. Therefore, the thickness of the antenna coil is reduced, and it becomes easy to realize a reduction in thickness and height of the antenna coil.
Further, since the connection portion between the lead terminal and the electrode is accommodated in the notch, the connection reliability of the lead terminal can be improved.
Further, when the antenna coil of this embodiment is used as a data transmission / reception card antenna for a portable electronic key, it is possible to save space in the electronic key.

Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. .
For example, in the above embodiment, the substrate is disposed on one side of the coil. However, in the present invention, the substrate may be disposed on both sides. Notches with electrodes to which the lead terminals are connected can be provided on either or both substrates.

  In the above embodiment, each lead terminal of each coil is connected to a different notched electrode, but the present invention is not particularly limited to this. It is also possible to connect a plurality of lead terminals (for example, a set of a plurality of coil lead terminals or a set of a coil lead terminal and an external circuit lead terminal) to one notch.

  When a plurality of coils are provided, one of these coils (for example, the Z-axis coil) is subjected to heat treatment by applying a conductive paste along a desired coil shape on at least one side of the printed coil sheet or substrate. The obtained coil sheet can be used. The printed coil sheet can be produced, for example, by forming a highly conductive metal thin film on the surface of an insulating substrate by sputtering, plating, or the like, and then removing portions other than the coil and terminals by etching. In this case, the lead terminal of the coil constituted by the winding is connected to the electrode provided in the cutout on the side surface of the substrate in the above-described form.

  The present invention is not limited to a vehicle keyless entry system (electronic key system) or the like, but can be used for an antenna coil used for an IC card or the like.

It is (a) bottom view which shows an example of the antenna coil of this invention, (b) sectional drawing. It is (a) top view and (b) sectional view showing an XY coil unit in the antenna coil of FIG. It is a schematic perspective view which shows an example of the connection structure of the lead terminal of a coil.

Explanation of symbols

L ... Lead terminal, 1 ... Antenna coil, 2 ... Board (printed wiring board), 2a ... Side face of the board, 7 ... Notch (half-cut through hole), 8 ... Electrode, 11-13 ... Coil, 11a-13a, 11b ~ 13b Lead terminal.

Claims (2)

  A notch is formed on a side surface of the substrate disposed along the coil, an electrode is provided on an inner end surface of the notch, and a lead terminal of the coil extends to an inner end surface of the notch of the substrate; and An antenna coil characterized by being connected to an electrode.   2. The antenna coil according to claim 1, wherein the substrate is a printed wiring board, and the notch having an electrode on the inner end face is a half-cut through hole formed in the printed wiring board.

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