JP2004343679A - Antenna and communication system using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna and a communication system using the same with which locking/unlocking of a vehicle door or rotation of a camera table is performed under remote control and which realize desired directivity even without disposing another antenna near the antenna. <P>SOLUTION: This invention provides advantageous effect that the antenna is obtained which is constituted by arranging a sub-core part 11 formed of a magnetic substance near a core part 1 formed of a magnetic substance, and realizes the desired directivity even without disposing the other antenna near the antenna and that communication system using the same is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antenna for remotely controlling locking and unlocking of a vehicle door, rotation of a camera stand, and the like, and a communication system using the same.

  2. Description of the Related Art In recent years, as antennas for remotely controlling the locking and unlocking of vehicle doors and communication systems using the same have become widespread, antennas that can easily achieve desired directivity even when the antennas are mounted at any place in a vehicle, and the use of such antennas. There is a need for an existing communication system.

  Such a conventional antenna and a communication system using the same will be described with reference to FIGS.

  FIG. 3 is a plan view of a conventional antenna, in which 1 is a core portion formed of a magnetic material such as ferrite, 2 is a holding portion formed of a film-like sheet made of a dielectric material, and a holding portion 2 is provided on the core portion 1. It is wound more than one turn in close contact.

  Reference numeral 3 denotes a coil, which is formed by winding a linear conductor on the outside of the holding unit 2, and the coil 3, the core unit 1, and the holding unit 2 constitute an antenna.

  A is a directivity indicating a range where the energy of the electromagnetic wave is equal to or higher than a predetermined intensity, and spreads substantially spherically around the vicinity of the left and right ends of the core 1.

  A capacitor (not shown) and a resistor (not shown) are connected in series to the coil 3, and both ends thereof are electrically connected to control means (not shown) to form a series resonance circuit. Have been.

  A communication system is configured by combining these with a card (not shown) unique to a vehicle which is usually carried by a driver and communicates with them.

  The resonance frequency is determined by the coil 3 and the capacitor. If the resonance frequency is out of the predetermined range, the coil 3 is removed, the linear conductor is wound, and then both ends are connected, or the capacitor is replaced. To adjust the resonance frequency.

  Next, the directivity when this antenna is mounted on a vehicle will be briefly described below.

  As shown in the conceptual diagram of the directivity of the antenna when mounted on the vehicle in FIG. 4, the antenna is attached to a fixed portion for mounting mirrors near the driver's seat side and the passenger's seat side door of the vehicle. The direction of the core portion 1 is substantially parallel to the traveling direction of the vehicle, and the left end of the core portion 1 is arranged to be slanted downward, and the right end thereof is arranged to be slanted upward.

  Therefore, the directivity A of the antenna is such that the vicinity of the left end faces downward and the vicinity of the right end faces upward.

  It should be noted that the right end is turned straight up rather than straight because the driver of the vehicle usually carries a unique card in the pants or jacket pocket, etc., so the height range of the pants or jacket pocket is limited. This is because directivity including the range of the height of the window of the vehicle is required in FIG. 4, but in this case, the upper part on the left end side, which faces downward, satisfies the desired directivity. Will not be.

  Therefore, in this case, another similar antenna (not shown) is arranged near the antenna, and the left end of the core portion 1 of the antenna is licked upward, so that the left end side The directivity was extended to the range of the height of the window of the section, and the overall directivity was satisfied.

  In the above configuration, the control unit periodically outputs a signal requesting transmission of the authentication code to the card unique to the vehicle, and the antenna converts the signal into an electromagnetic wave having a predetermined resonance frequency and transmits the signal.

  When the driver carrying the unique card moves away from the vehicle and goes out of the directivity A and cannot receive the authentication code, the door is automatically locked.

  Thereafter, when the driver carrying the unique card returns and enters the directivity A and the card receives this electromagnetic wave, the card converts the signal of the authentication code into an electromagnetic wave and transmits it, and the antenna receives this electromagnetic wave. When the control unit recognizes that the transmitted authentication code is correct, the door of the vehicle is automatically unlocked.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP-A-6-158926

  However, in the above-mentioned conventional antenna and the communication system using the same, it is necessary to arrange another similar antenna near the antenna in order to achieve desired directivity.

  An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an antenna capable of achieving desired directivity without disposing another antenna near an antenna and a communication system using the antenna. And

  In order to achieve the above object, the present invention has the following configuration.

  The invention according to claim 1 of the present invention provides an antenna by providing a sub-core portion formed of a magnetic material near a core portion formed of a magnetic material, wherein the sub-core portion is provided near a core portion. By providing, the direction of the magnetic field lines of the core portion near the sub-core portion can be changed to the sub-core portion side, so that the directivity range can be changed, so that another antenna is not disposed near the antenna. Has an effect that an antenna capable of realizing a desired directivity can be obtained.

  According to a second aspect of the present invention, in the first aspect of the present invention, a holding means for movably holding the sub-core portion near the outer periphery of the core portion is provided, and the holding means facilitates the position of the sub-core portion. Therefore, it is possible to easily manufacture an antenna capable of achieving a desired directivity.

  According to a third aspect of the present invention, in the first aspect of the present invention, a coil is wound around the outer periphery of the sub-core portion, and both ends of the coil are open. Mutually coupled with the coil, the inductance of the coil in the core changes, and the resonance frequency can be changed, so the resonance frequency can be easily adjusted without repeating the work of replacing the coil or capacitor in the core. It has the effect that it can be performed.

  According to a fourth aspect of the present invention, there is provided a communication system for performing communication with the outside via the antenna according to the first aspect, and has an operation of obtaining a communication system capable of realizing a desired directivity. .

  As described above, according to the present invention, it is possible to obtain an advantageous effect that it is possible to obtain an antenna capable of achieving desired directivity without disposing another antenna near an antenna and a communication system using the antenna. .

  Hereinafter, embodiments of the present invention will be described with reference to FIG. 1 and FIG.

  The same components as those described in the section of the background art are denoted by the same reference numerals, and detailed description will be simplified.

(Embodiment)
FIG. 1 is a plan view of an antenna according to an embodiment of the present invention, in which 1 is a prismatic core portion formed of a magnetic material such as ferrite or iron, and 2 is a film-shaped dielectric material such as polyethylene terephthalate. In the holding section made of a sheet, the holding section 2 is wound on the core section 1 in close contact with the core section 1 or more.

  Reference numeral 11 denotes a prismatic sub-core portion formed of a magnetic material such as ferrite, and 12 denotes a case made of a dielectric resin such as polybutylene terephthalate as holding means. The case 12 includes the core 1 and the sub-core 11. It is inserted movably in the left-right direction.

  By filling a flexible dielectric resin (not shown) such as silicone in the vicinity of the left end of the sub-core 11 and the core 1, the sub-core 11 is fixed to the upper left end of the core 1. I have.

  Reference numeral 3 denotes a coil, which is formed by winding a linear conductor on the outside of the holding unit 2, and the coil 3 and the core unit 1, the sub-core unit 11, the case 12, and the holding unit 2 constitute an antenna. I have.

  A1 is a directivity indicating a range in which the energy of the electromagnetic wave is equal to or higher than a predetermined intensity, and the right side of the core portion 1 spreads substantially spherically around the right end as in the case of the background art.

  However, on the left side of the core 1, the lines of magnetic force coming out from the vicinity of the left end are attracted to the sub-core 11, so that the intentionality A1 on the left becomes substantially spherical around the vicinity of the upper end of the sub-core 11.

  By providing the sub-core portion 11 made of a magnetic material in the vicinity of the core portion 1 as described above, the direction of the magnetic field lines in the vicinity of the core portion 1 can be changed to the sub-core portion 11 side. The range can be changed.

  Since the density of the lines of magnetic force is higher near the left and right ends of the core part 1, the range of the directivity A1 can be changed more effectively as the sub-core part 11 is provided near the left and right ends of the core part 1.

  Further, the range of directivity formed by the sub-core portion 11 secondary radiating the magnetic force lines by passing the magnetic lines of force radiated from the core portion 1 through the sub-core portion 11 is determined by setting the size of the sub-core portion 11 to the core portion 1. The larger, the larger.

  A capacitor (not shown) and a resistor (not shown) are connected in series to the coil 3, and both ends thereof are electrically connected to control means (not shown) to form a series resonance circuit. Have been.

  A communication system is configured by combining these with a card (not shown) unique to a vehicle which is usually carried by a driver and communicates with them.

  The resonance frequency is determined by the coil 3 and the capacitor. If the resonance frequency is out of the predetermined range, the coil 3 is removed, the linear conductor is wound, and then both ends are connected, or the capacitor is replaced. To adjust the resonance frequency.

  Next, the directivity when this antenna is mounted on a vehicle will be briefly described below.

  As shown in the conceptual diagram of the directivity of the antenna when mounted on the vehicle in FIG. 2, the antenna is mounted on a fixed portion for mounting mirrors near the driver's seat side and the passenger's seat side door of the vehicle. The direction of the core portion 1 is substantially parallel to the traveling direction of the vehicle, and the left end of the core portion 1 is arranged to be slanted downward, and the right end thereof is arranged to be slanted upward.

  However, since the sub-core portion 11 is fixed to the upper left end of the core portion 1, the directivity A1 near the left end is directed obliquely upward.

  The directivity A1 near the right end is slanted upward because the right end is arranged so as to be slanted upward.

  Since the driver of the vehicle usually carries his or her own card in the pocket of the pants or jacket, directivity including the height range of the pockets of the pants or jacket is required. In other words, in FIG. Is required. In this case, since the directivity A1 near the left and right ends covers at least the range of the height of the window of the vehicle of the driver of the vehicle, the desired directivity is required. Are satisfied.

  In the above configuration, the control unit periodically outputs a signal requesting transmission of the authentication code to the card unique to the vehicle, and the antenna converts the signal into an electromagnetic wave having a predetermined resonance frequency and transmits the signal.

  Then, when the driver carrying the unique card moves away from the vehicle and comes out of the directivity A1 and cannot receive the authentication code, the door is automatically locked.

  Thereafter, when the driver carrying the unique card returns and enters the directivity A1 and the card receives this electromagnetic wave, the card converts the signal of the authentication code into an electromagnetic wave and transmits it, and the antenna receives the electromagnetic wave. When the control unit recognizes that the transmitted authentication code is correct, the door of the vehicle is automatically unlocked.

  As described above, according to the present embodiment, the antenna is configured by providing the sub-core portion 11 formed of a magnetic material in the vicinity of the core portion 1 formed of a magnetic material, whereby the core portion 1 near the sub-core portion 11 is formed. Can be changed to the sub-core portion 11 side, and thereby the range of the directivity A1 can be changed. Therefore, a desired directivity can be realized without disposing another antenna near the antenna. An antenna and a communication system using the same can be obtained.

  Further, by providing a case 12 made of a dielectric resin as a holding means for movably holding the sub-core portion 11 near the outer periphery of the core portion 1, for example, the directivity A1 on the left side is slightly shifted rightward from the position in FIG. If it is desired to move the sub-core part 11 to the case 12, the sub-core part 11 movably inserted in the left-right direction is moved slightly to the right from the position shown in FIG. 1 and then fixed with a dielectric resin. For example, an antenna capable of realizing a desired directivity can be easily manufactured.

  Then, after winding a holding portion (not shown) made of a dielectric film sheet around the outer periphery of the sub-core portion 11, a coil (not shown) is wound, so that both ends of the coil are open. However, since this coil is mutually coupled with the coil 3 of the core unit 1, the inductance of the coil 3 of the core unit 1 changes, and the resonance frequency can be changed, the coil 3 and the capacitor of the core unit 1 are replaced. It is possible to easily adjust the resonance frequency without repeating the work of replacing.

  In the above description, a communication system in which an antenna is provided in a vehicle and a door of the vehicle is locked and unlocked by remote control has been described. Alternatively, an antenna may be provided in a door or a locker of a house to provide an antenna. The present invention can also be implemented as a communication system that remotely controls locking and unlocking of doors of lockers and the like.

  Further, instead of locking and unlocking the door, an antenna for remotely controlling various operations such as rotation of the camera base and a communication system using the same may be used.

  Further, the description has been given as a bidirectional communication system in which both the card and the antenna specific to the vehicle transmit and receive. However, instead of this, for example, a vehicle specific to lock and unlock the door by inserting it into the keyhole of the vehicle door. The driver of the vehicle presses the transmission button of the key in which the key and the transmission unit are integrated, and transmits an electromagnetic wave of a unique authentication code from the transmission unit of the key. A one-way communication system that locks and unlocks the data may be used.

  Although the shapes of the core portion 1 and the sub-core portion 11 are linear prismatic shapes, the shape may be a cylindrical shape or a curved shape.

  In addition, the sub-core portion 11 is provided at one location on the upper left end of the core portion 1, but in addition, a plurality of sub-core portions may be provided near the core portion, such as providing another location on the upper right end. .

  Further, the shape of the core portion may be an integrated one in which the core portion 1 and the sub-core portion 11 are combined.

  In the above description, it has been described that the coil is formed by winding the linear conductor around the outer periphery of the holding portion, but the linear conductor is coated with a dielectric material such as trivinyl butyral resin. At the same time, the coated linear conductor may be wound directly on the outer periphery of the core portion 1 or the sub-core portion 11 instead of the outer periphery of the holding portion to form a coil.

  ADVANTAGE OF THE INVENTION The antenna by this invention and the communication system using the same have the advantageous effect that the antenna which can implement | achieve desired directivity without arrange | positioning another antenna near an antenna, and the communication system using the same can be obtained. The present invention is useful for an antenna that remotely controls locking and unlocking of a vehicle door, rotation of a camera stand, and the like, and a communication system using the antenna.

Plan view of an antenna according to an embodiment of the present invention Conceptual diagram of antenna directivity when mounted on the same vehicle Top view of conventional antenna Conceptual diagram of antenna directivity when mounted on the same vehicle

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Core part 2 Holding part 3 Coil 11 Sub-core part 12 Case

Claims (4)

An antenna comprising: a core formed of a magnetic material; and a coil wound around the outer periphery of the core, wherein a sub-core formed of a magnetic material is provided near the core. 2. The antenna according to claim 1, further comprising a holding means for movably holding the sub-core portion near the outer periphery of the core portion. The antenna according to claim 1, wherein a coil is wound around the outer periphery of the sub-core portion. A communication system for communicating with the outside via the antenna according to claim 1.

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