JP2017046130A - Magnetic field radiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance detection sensitivity when a magnetic field incident device detects a magnetic field radiated by a magnetic field radiation device.SOLUTION: In an example, antennas are disposed in an XZ plane and in a YZ plane. When a magnetic field is radiated from a plurality of plane antennas, since a magnetic flux is incident from any one of the antennas of the magnetic field radiation device, even when electric energy obtained from the magnetic field radiated by a certain antenna of the magnetic field radiation device becomes 0, electric energy obtained from a magnetic field radiated by other antennas of the magnetic field radiation device is not 0, thus a range in which a magnetic field can be detected expands.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnetic field radiation device, a magnetic field incident device, and a communication system.

  In the conventional magnetic field detection method, for example, a magnetic field radiation device uses a uniaxial antenna, and a magnetic field incident device uses a triaxial antenna.

FIG. 35 is a diagram illustrating an example of an antenna structure of a conventional magnetic field incident device.
As shown in FIG. 35, the loop antenna of the magnetic field incident device includes, for example, three loop antennas 2x, 2y, and 2z. When the X, Y, and Z axes are set as shown in FIG. 35, the loop antennas 2x, 2y, and 2z detect magnetic field components parallel to the X, Y, and Z axes, respectively. That is, the magnetic field incident device includes antennas (2x, 2y, 2z) that detect magnetic field components in three directions orthogonal to each other.

FIG. 36 is a diagram showing another example of the antenna structure of the conventional magnetic field incident device.
As shown in FIG. 36, the magnetic field incident device determines the magnitudes of the output signals of the amplifiers 21x, 21y, and 21z that amplify the magnetic field components detected by the loop antennas 2x, 2y, and 2z, and the amplifiers 21x, 21y, and 21z. Squarer 22x, 22y, 22z to square, adder 23 to add the magnitude of the output signal of each squarer 22x, 22, 22z, and the square of the output signal of adder 23 And a 1/2 squarer 24.

JP2013-125991A

  For example, when a normal IC card using a planar loop antenna is used as a magnetic field incident device and is brought close to the vicinity of the planar loop antenna on the magnetic field radiation device side, the received power is insufficient depending on the angle of both antennas, and the magnetic field cannot be detected. Therefore, it has not been possible to realize a communication service in which communication using a radio wave or a magnetic field is started when a magnetic field is detected without depending on the angle of the IC card.

  FIG. 37 is a diagram showing an example of magnetic field radiation in the case where the magnetic flux lines of the loop antenna of the magnetic field radiation device and the loop antenna of the magnetic field incidence device are parallel, and FIG. 38 shows the magnetic flux lines and magnetic fields of the loop antenna of the magnetic field radiation device. It is a figure which shows the example of magnetic field radiation when the loop antenna of an incident device is perpendicular | vertical. FIGS. 37 and 38 are examples when a magnetic field incident device (for example, an IC card) including a loop antenna is brought close to the vicinity of the loop antenna of the magnetic field radiation device.

Loop antenna of the magnetic field radiation device of FIGS. 37 and 38:
When the magnetic field radiation device converts electrical energy into magnetic energy by the loop antenna, the magnetic flux lines are radiated perpendicular to the plane of the loop antenna of the magnetic field radiation device.
The loop antenna of the magnetic field injector in FIG.
Since the plane of the loop antenna of the magnetic field incident device and the magnetic flux lines are substantially parallel, the electric energy obtained from the magnetic energy by the loop antenna of the magnetic field incident device becomes almost zero.
The loop antenna of the magnetic field injector in FIG.
Since the magnetic flux lines are perpendicularly incident on the plane of the loop antenna of the magnetic field incident device, the electric energy obtained from the magnetic energy by the loop antenna of the magnetic field incident device is maximized.
In FIG. 37 and FIG. 38, the center position of the loop antenna of the magnetic field incident device is the same, but the angle is different, which causes the above difference.

The magnetic field H is a vector field having a magnitude and direction. The magnetic flux density B is B = μH (μ is magnetic permeability).
When the area is S, the magnetic flux Φ is Φ = BS, and the magnetic flux Φ is proportional to the number of magnetic flux lines penetrating the curved surface.
The magnetic flux Φ is also proportional to the magnetic field H. That is, the isomagnetic line is a line indicating that the norm (magnitude) of the magnetic flux lines passing through the curved surface is constant.
Although the norm of the magnetic flux lines is constant on the isomagnetic field lines, that is, the magnetic energy is constant, the phenomenon of the loop antenna of the magnetic field incident apparatus in FIGS. 37 and 38 is obtained by the magnetic field incident apparatus depending on the angle of the loop antenna. This means that the electrical energy that is produced is different.
The electric energy obtained by the loop antenna of the magnetic field incident device (IC card) is 0 in FIG. 37 and the maximum in FIG. As described above, conventionally, it has not been possible to realize a communication service in which communication using a radio wave or a magnetic field is started when the magnetic field is detected without depending on the angle of the magnetic field incident device (IC card).

FIG. 39 is a diagram illustrating a magnetic field obtained when a magnetic field is simultaneously output from a triaxial antenna.
Three antennas are arranged so as to radiate magnetic fields in the X-axis, Y-axis, and Z-axis directions, respectively. The magnetic fields at this time are Hx, Hy, and Hz, respectively.
When magnetic fields are output simultaneously from three antennas, the magnetic fields are combined to obtain a combined magnetic field H. This state has the same result as the above example, and means that the electric energy obtained by the magnetic field incident device differs depending on the angle of the loop antenna of the magnetic field incident device.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique for increasing detection sensitivity when a magnetic field incident device detects a magnetic field radiated by a magnetic field radiation device.

  In order to solve the above-described problem, the first aspect of the present invention is a communication system that starts communication using an electric field, a magnetic field, or a radio wave as a medium when the magnetic field radiating device detects a magnetic field radiated by the magnetic field radiation device. (1) having an antenna in each of a plurality of planes having different axes, or (2) having an antenna in each of a plurality of planes parallel to each other, or (3) the same A plurality of antennas are provided on a plane, or two or more antennas (1), (2), and (3) are provided, and a magnetic field is radiated from each antenna.

  A second aspect of the present invention is a magnetic field incident device of a communication system that starts communication using an electric field, a magnetic field, or a radio wave as a medium triggered by detecting the magnetic field radiated by the magnetic field radiation device with the magnetic field incident device, An antenna that generates a non-modulated wave of electric energy by converting the magnetic field energy radiated by the magnetic field radiation device, and a magnetic field that determines whether the intensity of the non-modulated wave is higher than a predetermined threshold. And detecting for communication when the intensity of the non-modulated wave is higher than the threshold.

  The third aspect of the present invention is a communication system, comprising the magnetic field radiation device according to the first aspect of the present invention and the magnetic field incident device according to the second aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the detection sensitivity at the time of a magnetic field injection apparatus detecting the magnetic field which a magnetic field radiation apparatus radiates | emits can be improved.

It is a figure which shows the example which arrange | positions an antenna in the several plane from which an axis | shaft mutually differs in a magnetic field radiation apparatus. It is a figure which shows the example which arrange | positions a several antenna on the same plane in a magnetic field radiation apparatus. It is a figure which shows the example which each arrange | positions an antenna in the some parallel plane in a magnetic field radiation apparatus. It is a figure which shows the example which arrange | positions an antenna by the combination of several planes in a magnetic field radiation apparatus. It is a figure which shows the example of an unmodulated wave. It is a figure which shows the block diagram (3-axis antenna) of a magnetic field radiation apparatus. It is a figure which shows the example of the sequence of a communication system. It is a figure which shows another example of the sequence of a communication system. It is a figure which shows the example of the structure of a magnetic field injection apparatus. It is a figure which shows the example which each installs an antenna in a mutually different plane in a magnetic field radiation | emission apparatus, and radiates | emits a magnetic field simultaneously. It is a figure which shows the example which installs one each in a mutually parallel plane in a magnetic field radiation | emission apparatus, and radiates | emits a magnetic field simultaneously. It is a figure which shows the example which installs two antennas in the same plane in a magnetic field radiation | emission apparatus, and radiates | emits a magnetic field simultaneously. It is a figure which shows the example which installs two antennas in the same plane in a magnetic field radiation apparatus, and also installs one antenna in a different plane, and radiates | emits a magnetic field simultaneously. In a magnetic field radiation apparatus, it is a figure which shows the example which allocates the time slot radiated | emitted from arbitrary one antenna among several antennas by a time division. In a magnetic field radiation apparatus, it is a figure which shows the example which allocates the time slot radiated | emitted from arbitrary several antennas among several antennas by a time division. It is a figure which shows the example which assigns a time slot periodically to three antennas by a time division in a magnetic field radiation apparatus. It is a figure which shows the example which assigns a time slot periodically to six antennas by a time division in a magnetic field radiation apparatus. It is a figure which shows the example which allocates a time slot with a different period from FIG. 16 in a magnetic field radiation apparatus. It is a figure which shows the example which provides the time which stops the radiation | emission of a magnetic field temporarily in a magnetic field radiation apparatus, and allocates a time slot. It is a figure which shows the example which provides the time which overlaps with the time slot before and behind, and allocates a time slot. It is a figure which shows the example which allocates a time slot to two antennas in duplicate among three antennas. It is a figure which shows the example which allocates a time slot by duplication to every 2 out of 6 antennas. It is a figure which shows the example which allocates many time slots with respect to the antenna with high importance. It is a figure which shows the example installed by making two planes which each arrange | positioned one antenna orthogonal. It is a figure which shows the example installed by making three planes which each arrange | positioned one antenna orthogonal. It is a figure which shows the example which uses a loop coil antenna for a magnetic field radiation apparatus. It is a figure which shows the example which uses a resonance type loop coil antenna as a loop coil antenna. It is a figure which shows the example which uses a negative phase type loop coil antenna as a loop coil antenna. It is a figure which shows the block diagram (uniaxial antenna) of a magnetic field injection apparatus. It is a figure which shows the example of the flowchart of a magnetic field injection apparatus. It is a figure which shows the example of the threshold value of received power. It is a figure which shows the block diagram (triaxial antenna) of a magnetic field injection apparatus. It is a figure which shows the block diagram (3-axis antenna: magnetic field communication) of a magnetic field injection apparatus. It is a figure which shows the example of a communication system. It is a figure which shows the example about the antenna structure of the conventional magnetic field injection apparatus. It is a figure which shows another example about the antenna structure of the conventional magnetic field injection apparatus. It is a figure which shows the example of magnetic field radiation | emission when the magnetic flux line of the loop antenna of a magnetic field radiation apparatus and the loop antenna of a magnetic field injection device are parallel. It is a figure which shows the example of a magnetic field radiation | emission when the magnetic flux line of the loop antenna of a magnetic field radiation apparatus and the loop antenna of a magnetic field injection apparatus are perpendicular | vertical. It is a figure which shows the magnetic field obtained when a magnetic field is simultaneously output from a triaxial antenna.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Example 1]
In the first embodiment, the first feature of the present invention will be described.
The first feature is the above-described magnetic field emission device in a communication system that starts communication using an electric field, magnetic field, or radio wave as a medium triggered by detection of a magnetic field radiated by the magnetic field emission device with a magnetic field incidence device. It has the following characteristics.

  That is, the magnetic field radiation device (1) has an antenna on each of a plurality of planes having different axes, or (2) has an antenna on each of a plurality of planes parallel to each other, or (3) the same plane Or a plurality of antennas (1), (2), and (3), and radiates a magnetic field from each antenna.

FIG. 1 is a diagram illustrating an example in which antennas are arranged on a plurality of planes having different axes from each other in a magnetic field radiation device.
Specifically, this is an example in which antennas are arranged on the XZ plane and the YZ plane, respectively.
Each plane does not have to be orthogonal. The number of planes may be three or more. The antennas do not have to intersect. The antenna only needs to radiate a magnetic field, and a planar antenna such as a loop antenna or a patch antenna can be applied. The antenna does not depend on the shape, size, and thickness, and may be different for each plane.
Effect: For example, when a magnetic field is radiated from an antenna having a plurality of planes as shown in the figure, a magnetic flux line from one of the antennas of the magnetic field radiation device is incident on the antenna of the magnetic field radiation device. Even if the electric energy obtained from the magnetic field radiated by is zero, the electric energy obtained from the magnetic field radiated by other antennas of the magnetic field radiation device is not zero, and the range in which the magnetic field can be detected is expanded.
For example, the magnetic field may be radiated separately. Further, the magnetic field may be radiated at an arbitrary timing.

FIG. 2 is a diagram illustrating an example in which a plurality of antennas are arranged on the same plane in the magnetic field radiation device.
Specifically, this is an example in which a plurality of antennas are arranged on the XZ plane.
The number of antennas on the same plane may be three or more. A plurality of planes having different numbers of antennas may be combined.
Effect: As in FIG. 1, since the magnetic flux lines from any one of the magnetic field radiation devices are incident on the antenna of the magnetic field incidence device, the electric energy obtained from the magnetic field radiated by the antenna with the magnetic field radiation device is 0. Even in this case, the electric energy obtained from the magnetic field radiated by the other antennas of the magnetic field radiation device is not zero, so that the range in which the magnetic field can be detected is expanded.
For example, the magnetic field may be radiated separately. Further, the magnetic field may be radiated at an arbitrary timing.

FIG. 3 is a diagram illustrating an example in which antennas are arranged on a plurality of planes parallel to each other in the magnetic field radiation device.
Specifically, this is an example in which the antennas are arranged on a plurality of parallel planes having different Y-axis positions on the XZ plane.
The number of planes may be three or more. The number of antennas on the same plane may be three or more.
Effect: As in FIGS. 1 and 2, since the magnetic flux lines from any one of the magnetic field radiation devices are incident on the antenna of the magnetic field incidence device, the electricity obtained from the magnetic field radiated by the antenna with the magnetic field radiation device is obtained. Even if the energy becomes zero, the electric energy obtained from the magnetic field radiated by the other antenna of the magnetic field radiation device is not zero, and thus the range in which the magnetic field can be detected is expanded.
For example, the magnetic field may be radiated separately. Further, the magnetic field may be radiated at an arbitrary timing.

FIG. 4 is a diagram illustrating an example in which antennas are arranged by a combination of a plurality of planes in a magnetic field radiation device.
Specifically, this is an example in which a plurality of antennas are combined on the XZ plane and one antenna is combined on the YZ plane.
The antennas may intersect.
The planes of FIGS. 1-3 can be combined. The combination is not limited to the example of FIG.
The number of antennas may be different for each plane.
When a plurality of planes are combined, the probability that the magnetic flux lines from any of the antennas of the magnetic field radiation device are incident on the antenna of the magnetic field incidence device increases, so that the range in which the magnetic field can be detected is further expanded.
For example, the magnetic field may be radiated separately. Further, the magnetic field may be radiated at an arbitrary timing.

FIG. 5 is a diagram illustrating an example of an unmodulated wave.
In each embodiment, the magnetic field radiated by the magnetic field radiation device is an unmodulated wave having a waveform as shown in the figure.

FIG. 6 is a block diagram (three-axis antenna) of the magnetic field radiation device.
Specifically, it is an example of a block diagram for radiating a magnetic field with three antennas arranged on three different planes and starting communication by radio waves.
The magnetic field radiation device includes three antennas, a magnetic field unmodulated wave generation unit 1, a microcomputer 2, and a communication unit 3.
The antennas are arranged on the XY plane, the XZ plane, and the YZ plane, respectively. The antenna is described from the side.
The magnetic field unmodulated wave generator 1 generates an unmodulated wave and radiates the magnetic field from the antenna by the unmodulated wave. When this is detected on the incident side, the communication unit 3 communicates by radio waves, for example, triggered by the detection.
Moreover, the communication part 3 can start the communication by any one of an electric field, a magnetic field, and a radio wave irrespective of a radio wave.

FIG. 7 is a diagram illustrating an example of a sequence of the communication system.
Specifically, this is an example in which communication by the magnetic field radiation device of FIG. 6 is started.
For example, the magnetic field radiation device starts moving and performs polling using an unmodulated wave caused by a magnetic field. When the magnetic field incident device detects a magnetic field, communication by the magnetic field is started and polling is stopped. Any data can be sent by communication, and device ID, authentication key, data, etc. can be sent.

FIG. 8 is a diagram illustrating another example of the sequence of the communication system.
Specifically, this is an example in which communication by the magnetic field radiation device of FIG. 6 is started.
For example, the magnetic field radiation device starts moving and performs polling using an unmodulated wave caused by a magnetic field. When the magnetic field incident device detects a magnetic field, communication using radio waves is started and polling is stopped.

FIG. 9 is a diagram illustrating an example of the structure of the magnetic field incident device.
As the magnetic field incident device, for example, a so-called RFID (radio frequency identifier) shown in FIG. 9 can be used.
The magnetic field incident device has an IC chip and a coil antenna on a vinyl chloride substrate.
In the case of such a magnetic field injector, the sequence is as shown in FIG.

[Example 2]
In the second embodiment, the second feature of the present invention will be described.
The second feature is that each antenna radiates a magnetic field simultaneously in the magnetic field radiation device having the first feature.

FIG. 10 is a diagram illustrating an example in which antennas are installed on different planes in a magnetic field radiation device and simultaneously radiate a magnetic field.
You may combine the antenna which radiates | emits simultaneously with the antenna which radiates | emits separately.
The antenna is arranged on the XZ plane and the YZ plane. The plane of the drawing is the XY plane.
As in FIG. 1, when a magnetic field is radiated from a plurality of planar antennas as shown in the figure, magnetic flux lines from any one of the magnetic field radiation devices are incident on the antenna of the magnetic field radiation device. Even if the electric energy obtained from the magnetic field radiated by one antenna becomes zero, the electric energy obtained from the magnetic field radiated by another antenna of the magnetic field radiating device is not zero, and the range in which the magnetic field can be detected is widened.
Effect: As shown in FIG. 10, when a magnetic field is simultaneously radiated from a plurality of antennas, the magnetic field can be detected in a shorter time than when a magnetic field is radiated separately.

FIG. 11 is a diagram illustrating an example in which one antenna is installed on each of planes parallel to each other in the magnetic field radiation device and the magnetic field is radiated simultaneously.
You may combine the antenna which radiates | emits simultaneously with the antenna which radiates | emits separately.
The antennas are arranged in parallel to the XZ plane and at different positions on the Y axis. The plane of the drawing is the XY plane.
As in FIG. 2, when a magnetic field is radiated from a plurality of planar antennas as shown in the figure, magnetic flux lines from any one of the magnetic field radiation devices enter the antenna of the magnetic field radiation device. Even if the electric energy obtained from the magnetic field radiated by one antenna becomes zero, the electric energy obtained from the magnetic field radiated by another antenna of the magnetic field radiating device is not zero, and the range in which the magnetic field can be detected is widened.
Effect: As shown in FIG. 11, when a magnetic field is simultaneously emitted from a plurality of antennas, the magnetic field can be detected in a shorter time than when a magnetic field is emitted separately.

FIG. 12 is a diagram showing an example in which two antennas are installed on the same plane in a magnetic field radiation device and simultaneously radiate a magnetic field.
You may combine the antenna which radiates | emits simultaneously with the antenna which radiates | emits separately.
The antenna is arranged at a place where the position of the X axis on the XZ plane is different. The plane of the drawing is the XY plane.
Similarly to FIG. 3, when a magnetic field is radiated from a plurality of planar antennas as shown in the figure, magnetic flux lines from any one of the magnetic field radiation devices are incident on the antenna of the magnetic field radiation device. Even if the electric energy obtained from the magnetic field radiated by one antenna becomes zero, the electric energy obtained from the magnetic field radiated by another antenna of the magnetic field radiating device is not zero, and the range in which the magnetic field can be detected is widened.
Effect: As shown in FIG. 12, when a magnetic field is simultaneously emitted from a plurality of antennas, the magnetic field can be detected in a shorter time than when a magnetic field is emitted separately.

FIG. 13 is a diagram showing an example in which two antennas are installed on the same plane and one antenna is installed on a different plane, and a magnetic field is radiated simultaneously.
You may combine the antenna which radiates | emits simultaneously with the antenna which radiates | emits separately.
The antenna is arranged on the YZ plane where the X-axis position on the XZ plane is different. The plane of the drawing is the XY plane.
Similarly to FIG. 4, when a magnetic field is radiated from a plurality of planar antennas as shown in the figure, magnetic flux lines from any antenna of the magnetic field radiation device are incident on the antenna of the magnetic field radiation device. Even if the electric energy obtained from the magnetic field radiated by one antenna becomes zero, the electric energy obtained from the magnetic field radiated by another antenna of the magnetic field radiating device is not zero.
Effect: As shown in FIG. 13, when a magnetic field is simultaneously radiated from a plurality of antennas, the magnetic field can be detected in a shorter time than when a magnetic field is radiated separately.

[Example 3]
In the third embodiment, the third feature of the present invention will be described.
The third feature is that, in the magnetic field radiation device having the first feature, each antenna is assigned a time slot in a time division manner, and a magnetic field is radiated at the timing of the assigned time slot.

FIG. 14 is a diagram illustrating an example in which time slots radiating from any one antenna among a plurality of antennas are allocated in a time division manner in the magnetic field radiation device.
The magnetic field is radiated once from the antenna at a time when the magnetic field can be radiated.
Any number of timeslots may be allocated.
Effect: A magnetic field can be detected at an arbitrary timing.

FIG. 15 is a diagram illustrating an example in which time slots radiating from an arbitrary plurality of antennas among a plurality of antennas are allocated in a time division manner in the magnetic field radiation device.
A magnetic field is radiated once from each antenna at a time when the magnetic field can be radiated.
Any number of timeslots may be allocated.
Effect: Since the number of antennas is increased as compared with FIG. 14, the range in which a magnetic field can be detected at an arbitrary timing can be increased.

[Example 4]
In the fourth embodiment, the fourth feature of the present invention will be described.
The fourth feature is that in the magnetic field radiation device having the first feature, each antenna is assigned a time slot having periodicity in a time-sharing manner, and a magnetic field is emitted at the timing of the assigned time slot. . In other words, in addition to the third feature, the time slot has periodicity.

FIG. 16 is a diagram illustrating an example in which time slots are periodically allocated to three antennas in a time division manner in the magnetic field radiation device.
The magnetic field is periodically radiated from each antenna at a time when the magnetic field can be radiated.
The time slot may be interrupted halfway.
Since it does not depend on the number of antennas, only one antenna may have a period.
Effect: Since the number of times of radiating the magnetic field is increased as compared with the third embodiment, the probability that the magnetic field can be detected can be increased.

FIG. 17 is a diagram illustrating an example in which time slots are periodically assigned to six antennas in a time division manner in the magnetic field radiation device.
Effect: Since the number of antennas is increased as compared with FIG. 16, the range in which a magnetic field can be detected can be expanded.

FIG. 18 is a diagram illustrating an example in which time slots are periodically assigned to the magnetic field radiation device different from those in FIG.
Thus, any pattern may be used without depending on the pattern of the period.
Effect: Compared to FIG. 16, the number of time slots per unit time for a specific antenna increases, so that it is possible to increase the probability that a magnetic field can be detected by a highly important antenna, for example.

[Example 5]
In the fifth embodiment, the fifth feature of the present invention will be described.
A fifth feature is that there exists a time when no time slot is assigned to at least one antenna.
FIG. 19 is a diagram illustrating an example in which a time slot is allocated with a time for temporarily stopping the emission of the magnetic field in the magnetic field emission device.
Since it does not depend on the length of time to stop temporarily, it may be longer or shorter. Moreover, you may combine the state which has different time length and time to stop.
Effect: When a magnetic field is detected and communication such as confirmation of delivery is performed using the magnetic field, it is effective to prevent interference between detection and communication.

[Example 6]
In the sixth embodiment, the sixth feature of the present invention will be described.
The sixth feature is that the time slot is composed of a period that overlaps the previous time slot, a period that does not overlap the preceding and following time slots, and a period that overlaps the subsequent time slot.
FIG. 20 is a diagram illustrating an example in which time slots are allocated with a time overlapping with previous and subsequent time slots.
For example, the time slot of the antenna (# 2) is overlapped with the previous time slot assigned to the antenna (# 1) and the time slot after being assigned to the antenna (# 3). It consists of a period that does not overlap and a period that overlaps with a later time slot.
In order to prevent a state in which a magnetic field is not temporarily emitted due to temporal fluctuations in the magnetic field unmodulated wave generation unit 1 shown in FIG. 6, the time slots before and after are overlapped.
Since it does not depend on the overlapping time length, it may be long or short. Moreover, you may combine the state which has different time length and time to stop.
Effect: Since the magnetic field is always incident on the detection unit of the magnetic field injection device, the operation of the detection unit can be stabilized.

[Example 7]
In the seventh embodiment, the seventh feature of the present invention will be described.
The seventh feature is that time slots are assigned to a plurality of antennas simultaneously.
FIG. 21 is a diagram illustrating an example in which time slots are allocated to two of the three antennas in an overlapping manner.
Since it does not depend on the number of overlapping antennas, any number may be assigned at the same time.
Effect: If time slots are assigned to a plurality of antennas at the same time, parallel operation becomes possible, so that the possibility that the magnetic field injection device can detect becomes higher.

FIG. 22 is a diagram illustrating an example in which time slots are allocated to two of the six antennas in an overlapping manner.
Since it does not depend on the number of antennas to be selected, any number of antennas to be selected may be used. Effect: If there are a plurality of antennas, the angle of the magnetic field incident on the magnetic field incident device is different, so that the possibility that the magnetic field incident device can detect the magnetic field becomes higher.

[Example 8]
In the eighth embodiment, the eighth feature of the present invention will be described.
The eighth feature is that many time slots are allocated to highly important antennas.
FIG. 23 is a diagram illustrating an example in which many time slots are assigned to highly important antennas.
The antenna (# 1) is assigned a time slot once every two times, and the antenna (# 2) and the antenna (# 3) are assigned a time slot once every four times.
Since it does not depend on the number of antennas to be selected and the number of antennas, the number of assignments and the number of selection objects may be any number.
Also, a time slot that is not assigned and a time slot that is assigned a plurality of antennas at the same time may be combined.
Effect: By giving many time slots to a highly important antenna, the possibility that the magnetic field injector can detect the magnetic field becomes higher.

[Example 9]
In the ninth embodiment, the ninth feature of the present invention will be described.
The ninth feature is (1) that a plurality of planes having different axes are orthogonal to each other, and the number of the planes is 2 or 3.
FIG. 24 is a diagram showing an example in which two planes each having one antenna are arranged orthogonal to each other.
For example, the antennas are arranged in the XZ plane and the YZ plane.
Effect: Compared with the case where the planes on which the antennas are arranged are not orthogonal, the difference in the angle of the antenna is larger when the planes are orthogonal, and at least the magnetic field incident on one antenna is larger. As a result, it becomes easier to detect the magnetic field.

FIG. 25 is a diagram showing an example in which three planes each having one antenna are arranged orthogonally.
The antenna is arranged on the XZ plane, the YZ plane, and the XY plane.
Effect: Compared to the case where the planes on which the antennas are arranged are not orthogonal, the number of antennas with different angles increases, and it becomes easier to detect the magnetic field.

[Example 10]
In the tenth embodiment, the tenth feature of the present invention will be described.
The tenth feature is that at least one antenna is a loop coil antenna.
FIG. 26 is a diagram illustrating an example in which a loop coil antenna is used in the magnetic field radiation device.
One loop coil antenna is also called a loop antenna, and one with multiple windings is also called a coil antenna.
It does not depend on the shape of the loop coil antenna. Arbitrary shapes are possible including concentric, elliptical, rectangular, and cloud shapes. For example, a capacitor may be inserted. A similar antenna can be used for the magnetic field incident device.

[Example 11]
In the eleventh embodiment, an eleventh feature of the present invention will be described.
The eleventh feature is that at least one antenna is a resonant loop coil antenna or a reverse phase loop coil antenna.
FIG. 27 is a diagram illustrating an example in which a resonant loop coil antenna is used as the loop coil antenna.
One loop antenna is connected to the magnetic field unmodulated wave generating unit 1, and another loop antenna is not connected to the magnetic field unmodulated wave generating unit 1 and is arranged in the vicinity of the loop antenna.
Effect: Even if magnetic field resonance occurs and the energy supplied from the magnetic field radiation device to the antenna is at the same level, the resonance type can extend the communication distance than the normal type.

FIG. 28 is a diagram illustrating an example in which a reverse-phase loop coil antenna is used as the loop coil antenna.
One of the two loop antennas is for the positive phase and the other is for the negative phase, and both are connected to the magnetic field unmodulated wave generating unit 1.
Effect: The distance attenuation characteristic of the magnetic field strength can be made sharper than that of the normal type. Specifically, the distance attenuation of the magnetic field strength of the normal type is 60 dB / dec, whereas the reverse phase type is 100 dB / dec.
Similar to Example 10, it does not depend on the shape of the loop coil antenna. Arbitrary shapes are possible including concentric, elliptical, rectangular, and cloud shapes. For example, a capacitor may be inserted. A similar antenna can be applied to the magnetic field incident device.
The magnetic field radiation device may include at least two types of loop coil antennas, resonant loop coil antennas, and antiphase loop coil antennas.

[Example 12]
In the twelfth embodiment, the twelfth feature of the present invention will be described.
The twelfth feature is a magnetic field incident device of a communication system that starts communication using an electric field, magnetic field, or radio wave as a medium when the magnetic field radiating device detects a magnetic field radiated by the magnetic field radiating device. , Has the following characteristics.
That is, the magnetic field incident device converts the magnetic field energy radiated by the magnetic field radiation device into electric energy, generates an unmodulated wave of electric energy, and whether the intensity of the unmodulated wave is higher than a predetermined threshold. A magnetic field detector for determining whether or not, and communication is started when the intensity of the unmodulated wave is higher than a threshold value.

FIG. 29 is a block diagram (uniaxial antenna) of the magnetic field incident device.
Specifically, in the example of the block diagram for initiating communication by radio waves by causing the magnetic fields radiated by three planar antennas arranged on three different planes to enter one antenna of the magnetic field incident device. is there.
The antenna is arranged on the XY plane. The antenna is a planar antenna and is described from the side.
When a magnetic field is incident on the antenna, the antenna converts the magnetic field energy into electric energy and generates a non-modulated wave of electric energy. The magnetic field detector 11 determines whether or not the intensity of the unmodulated wave is higher than a predetermined threshold value, and notifies the microcomputer 12 of the result. When the intensity of the unmodulated wave is higher than the threshold value, the microcomputer 12 instructs the radio wave modulation / demodulation unit 13 and the radio wave modulation / demodulation unit 13 performs communication using the radio wave. The radio wave modulation / demodulation unit 13 drives the radio wave antenna with the modulated wave.
Note that the communication means can start communication using any one of an electric field, a magnetic field, and a radio wave, regardless of the radio wave.

FIG. 30 is a diagram illustrating an example of a flowchart of the magnetic field incident device.
The magnetic field is converted into a received signal by the antenna (S1), and the level of the received signal is compared with a preset threshold value (S3). If the level of the received signal is less than or equal to the threshold, the process returns to step S1. If the level of the received signal is higher than the threshold value, communication is started (S5), and the determination ends here.

FIG. 31 is a diagram illustrating an example of a threshold value of received power.
In FIG. 31, the received signal level is the actual received signal level expressed in decibels. z / a1 is a value obtained by dividing the distance z from the origin on the Z axis by the radius a1 of the loop antenna.
The level of the received signal decreases as z / a1 increases. Therefore, for example, when the position of z / a1 = 10 is set as the limit of the communicable area, the threshold value may be set to 60 dB. That is, the magnetic field incident device starts communication with the magnetic field radiation device when the level of the received signal is 60 dB or more. Therefore, communication can be performed only at the position of z / a1 = 10 or the communication area closer to the magnetic field radiation device.

  Note that the level of the received signal varies somewhat due to the influence of the surroundings even at the same position, so it is desirable to set the threshold value at a location where the slope of the level of the received signal is large. That is, in FIG. 31, it is desirable to determine the radius a1 and the current value so that the threshold is set at a location where the slope of the received signal level is large. By doing so, even if the level of the received signal varies somewhat, the position where the level of the received signal becomes equal to the threshold, that is, the position of the outer edge of the communication area does not change much. That is, it is possible to suppress a change in the size of the communication area (a change in the position of the outer edge of the communication area).

[Example 13]
In the thirteenth embodiment, a thirteenth feature of the present invention will be described.
A thirteenth feature is the magnetic field incident device having the twelfth feature, wherein a plurality of antennas that convert magnetic field energy radiated by the magnetic field radiation device into electric energy and generate unmodulated waves of electric energy, A magnetic field detector that determines whether the intensity of the unmodulated wave after synthesis is higher than the threshold value, and the intensity of the unmodulated wave after synthesis is higher than the threshold value. In this case, communication is started.

FIG. 32 shows an example of a block diagram for injecting magnetic fields radiated from three planar antennas arranged on three different planes into three antennas of the magnetic field incident device and starting communication by radio waves. FIG.
The antennas are arranged on the XY plane, the XZ plane, and the YZ plane, respectively. The antenna is a planar antenna and is described from the side.
When a magnetic field is incident on the antenna, the antenna converts the magnetic field energy into electric energy and generates a non-modulated wave of electric energy. The synthesizer 14 synthesizes this unmodulated wave. As a synthesis method, a general synthesis method can be used, and selection synthesis, equal gain synthesis, maximum ratio synthesis, and the like are preferably applied.

The magnetic field detector 11 determines whether or not the intensity of the unmodulated wave after synthesis is higher than a predetermined threshold value, and notifies the microcomputer 12 of the result. When the intensity of the unmodulated wave is higher than the threshold value, the microcomputer 12 instructs the radio wave modulation / demodulation unit 13 and the radio wave modulation / demodulation unit 13 performs communication using the radio wave. The radio wave modulation / demodulation unit 13 drives the modulated wave to the radio wave antenna.
Effect: Unlike FIG. 29, when a plurality of antennas in different directions are used, the number of antennas that can generate a large amount of electrical energy increases.

[Example 14]
In the fourteenth embodiment, a fourteenth feature of the present invention will be described.
The fourteenth feature is that the antenna is also used for magnetic field communication.
FIG. 33 is a block diagram (three-axis antenna) of the magnetic field incident device in that case.
In order to use detection as a magnetic field and communication as a magnetic field, the antenna is shared for radiation (communication) and incidence (detection) of the magnetic field.
The antennas are arranged on the XY plane, the XZ plane, and the YZ plane, respectively. The antenna is a planar antenna and is described from the side.

When a magnetic field is incident on the antenna, the antenna converts the magnetic field energy into electric energy and generates a non-modulated wave of electric energy. The synthesizer 14 synthesizes this unmodulated wave. As a synthesis method, a general synthesis method can be used, and selection synthesis, equal gain synthesis, maximum ratio synthesis, and the like are preferably applied.
The magnetic field detector 11 determines whether or not the intensity of the unmodulated wave after synthesis is higher than a predetermined threshold value, and notifies the microcomputer 12 of the result. When the intensity of the unmodulated wave is higher than the threshold value, the microcomputer 12 instructs the magnetic field modulation / demodulation unit 15 to perform communication using the magnetic field. The magnetic field modulator / demodulator 15 drives the three antennas that have received the magnetic field.

Effect: In FIGS. 6 and 32, the detection propagation means is a magnetic field and the communication propagation means is a radio wave. However, as shown in FIG. 33, the detection propagation means and the communication propagation means can be a magnetic field.
When the communication propagation means is a magnetic field, the communication unit also performs communication using the antenna that radiates the magnetic field in the magnetic field radiation device. In the magnetic field incident device, the number of antennas is not limited to three, and one antenna can be used as shown in FIG. 29, and the detection propagation means and the communication propagation means can be used as magnetic fields.

[Example 15]
In the fifteenth embodiment, a fifteenth feature of the present invention will be described.
A communication system having the fifteenth feature is a fifteenth feature comprising any one of the magnetic field radiation devices described above and one of the magnetic field incidence devices described above.
FIG. 34 is a diagram showing an example in which a magnetic field radiation device is attached to a wheelchair, and a magnetic field incident device is attached to a wall and an obstacle, and applied to a wheelchair collision prevention system.
The magnetic field radiating device periodically radiates a magnetic field, and when the magnetic field is incident on the magnetic field incident device, the magnetic field incident device transmits a signal indicating that it is dangerous to the magnetic field radiating device by radio waves.

DESCRIPTION OF SYMBOLS 1 ... Magnetic field unmodulated wave production | generation part 2, 12 ... Microcomputer 3 ... Communication part 11 ... Magnetic field detection part 13 ... Radio wave modulation / demodulation part 14 ... Synthesis | combination part 15 ... Magnetic field modulation / demodulation part

Claims (12)

A magnetic field radiation device of a communication system that starts communication using an electric field, a magnetic field, or a radio wave as a medium triggered by detecting a magnetic field radiated by the magnetic field radiation device with a magnetic field incidence device,
(1) having an antenna on each of a plurality of planes having different axes, or (2) having an antenna on each of a plurality of planes parallel to each other, or (3) having a plurality of antennas on the same plane, Alternatively, a magnetic field radiation device having two or more antennas of (1), (2), and (3), and radiating a magnetic field from each of the antennas. The radiating magnetic field is an unmodulated wave, or
The magnetic field radiation device according to claim 1, wherein the antenna is also used for magnetic field communication. The said each antenna radiates | emits a magnetic field simultaneously. The magnetic field radiation | emission apparatus of Claim 1 or 2 characterized by the above-mentioned. Each antenna is assigned a time slot in a time division manner, and radiates a magnetic field at the time of the assigned time slot, or
3. The magnetic field radiation device according to claim 1, wherein a time slot having periodicity is assigned to each antenna in a time-sharing manner, and a magnetic field is radiated at the timing of the assigned time slot.   5. The magnetic field radiation device according to claim 4, wherein there is a time when no time slot is allocated to at least one of the antennas. The time slot is
A period that overlaps the previous time slot,
A period that does not overlap the previous and next time slots,
A period that overlaps with a later time slot, or
The time slot is assigned to multiple antennas simultaneously, or
5. The magnetic field radiation device according to claim 4, wherein a large number of the time slots are allocated to highly important antennas.   The magnetic field radiation device according to any one of claims 1 to 6, wherein (1) the plurality of planes having different axes are orthogonal to each other, and the number of the planes is two or three. At least one of the antennas is (a) a loop coil antenna, or (b) a resonant loop coil antenna, or (c) a reverse phase loop coil antenna, or (a) the loop coil antenna and (b) The magnetic field radiation device according to claim 1, comprising at least two types of: a resonance type loop coil antenna of () and a reverse phase type loop coil antenna of (c). A magnetic field incident device of a communication system that starts communication using an electric field, a magnetic field, or a radio wave as a medium triggered by detecting the magnetic field radiated by the magnetic field radiation device with a magnetic field incident device,
An antenna that converts magnetic field energy radiated by the magnetic field radiation device into electrical energy, and generates an unmodulated wave of electrical energy;
A magnetic field detector for determining whether or not the intensity of the unmodulated wave is higher than a predetermined threshold,
Communication is started when the intensity of the unmodulated wave is higher than the threshold value. A plurality of antennas including the antenna that converts energy of a magnetic field radiated by the magnetic field radiation device into electric energy and generates an unmodulated wave of electric energy;
A synthesis unit that synthesizes each unmodulated wave,
The magnetic field detector determines whether the intensity of the unmodulated wave after the synthesis is higher than the threshold value,
The magnetic field incident device according to claim 9, wherein the magnetic field incident device starts communication when the intensity of the unmodulated wave after the synthesis is higher than the threshold value. The radiating magnetic field is an unmodulated wave, or
The magnetic field incidence device according to claim 9 or 10, wherein the antenna is also used for magnetic field communication. A magnetic field radiation device according to any one of claims 1 to 8,
A communication system comprising: the magnetic field incident device according to claim 9.

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