JP2006331279A - Reader/writer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interrogator system in a reader/writer system, where gate antennas can be closely and continuously arranged and gate antennas through which a responder passes can be discriminated. <P>SOLUTION: The interrogator system comprises a first loop antenna 1e, a second loop antenna 1f, a third loop antenna 1g, distributer/synthesizer 3 to be connected to respective loop antennas 1e-1g, an antenna switching device 6 connected to the distributor/synthesizer to switch a group of the first and second loop antennas 1e, 1f and a group of the second and third loop antennas 1f, 1g, and a reader/writer 4 connected to the antenna switching device 6. In the case of switching the groups of the loop antennas, the frequency of a non-operated loop antenna is shifted from the resonance frequency of the responder. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reader / writer system that detects a transponder, and more particularly, to a reader / writer system including an interrogator that can determine a gate antenna through which a transponder has passed when the gate antennas are continuously arranged without gaps.

A basic reader / writer system will be described with reference to FIG. FIG. 4 is a schematic configuration diagram of a basic reader / writer system.
As shown in FIG. 4, the basic reader / writer system has a pair of two loop antennas 1a and 1b, a distributor / synthesizer 3 to which each loop antenna 1a, 1b is connected, and its distributor / synthesizer. 3 is provided with an interrogator (reader / writer) 4 connected to 3, and a responder 10.

  The reader / writer system uses electromagnetic induction formed by the loop antennas 1a and 1b, the responder is supplied with power by a magnetic field, operates, and the frequency (response frequency) transmitted from the responder is set to the loop antenna 1a. , 1b and the responder 10 is detected by the reader / writer 4 via the distributor / synthesizer 3.

  Specifically, a response frequency transmitted from the responder 10 in response to the command when the responder 10 makes a currency while the responder 10 continues to send a command to the responder 10 that makes a currency in the responder detection area between the loop antennas. Is received by the loop antennas 1a and 1b so that the currency of the responder 10 is determined.

  When a reader / writer system composed of such a gate antenna and an interrogator is used to widen the entrance / exit or increase the number of management passages to enter / exit, the number of gate antennas will be increased, but there are the following problems.

First, since transponders operating at the same frequency are used, when gate antennas are used side by side, interference occurs between the antennas, that is, the antenna characteristics may change due to the influence of adjacent antennas.
For this reason, as shown in FIG. 5, it is necessary to arrange an iron plate (shielding plate 5) or the like made of a material that shields the magnetic field between the gate antennas forming a set.
FIG. 5 is a schematic configuration diagram when a plurality of gate antennas are arranged.
Incidentally, as a prior art provided with the above-described shielding plate (shielding plate), there is JP-A-2004-86597 “Interrogator system of reader / writer system” (see Patent Document 1).

Second, there is a method of supplying a magnetic field simultaneously to a plurality of gate antennas arranged in parallel in order to widen the entrance / exit. In this method, as shown in FIG. 6, the distributor / synthesizer 3 is combined in multiple stages.
FIG. 6 is a schematic configuration diagram in the case where a plurality of gate antennas are arranged and the distributor / combiner is combined in multiple stages.
In addition, in order to increase the width of the entrance / exit of the management area, at least one loop antenna is connected to the interrogator, and at least one loop-shaped conductive wire is installed within the range in which the induced magnetic field from the loop antenna is effective. There is a tag information management device (see Patent Document 2).

JP 2004-86597 A JP 2004-241929 A

However, in the first conventional method, when an iron plate that shields the magnetic field is installed near the antenna, an eddy current is generated in the iron plate, the magnetic field strength is reduced, and the detection range of the responder is narrowed. was there.
Therefore, it is necessary to make a certain distance between the antenna and the shield such as an iron plate installed between the gate antennas, and the distance between the gate antennas must be, for example, 20 cm or more. On the other hand, the lead dryer system occupies a lot of installation space.

  Further, in the second method, it is possible to install the gate antennas close to each other, but it is impossible to determine which gate antenna has passed.

  The present invention has been made in view of the above circumstances, and it is possible to arrange gate antennas continuously without a gap, and further, it is possible to determine which gate antenna a transponder has passed between. An object is to provide a vessel system.

  The present invention for solving the problems of the conventional example is an interrogator system of a reader / writer system that detects passage of a responder, and includes a first loop antenna, a second loop antenna, and a third loop antenna. A loop antenna, a distributor / combiner connected to each loop antenna, a distributor / synthesizer, a set of a first loop antenna, a second loop antenna, a second loop antenna, and a third loop antenna. It is characterized by having an antenna switcher for switching a set and a reader / writer connected to the antenna switcher.

  According to the present invention, an interrogator system of a reader / writer system that detects passage of a responder, which is connected to a first loop antenna, a second loop antenna, a third loop antenna, and each loop antenna A distributor / synthesizer, an antenna switch connected to the distributor / synthesizer, and a pair of the first loop antenna and the second loop antenna and a pair of the second loop antenna and the third loop antenna, and an antenna Since the interrogator system has a reader / writer connected to the switching device, it is possible to arrange the gate antennas continuously without any gaps, and further, it is possible to determine which gate antenna the responder has passed through. .

Embodiments of the present invention will be described with reference to the drawings.
An interrogator system of a reader / writer system according to an embodiment of the present invention includes a first loop antenna, a second loop antenna, a third loop antenna, a fourth loop antenna, and a first loop antenna. And a first distributor / synthesizer connected to the second loop antenna, a second distributor / synthesizer connected to the third loop antenna and the fourth loop antenna, and first and second distributors / synthesizers. And a reader / writer connected to the antenna switcher, and a reader / writer connected to the antenna switcher and switching the first loop antenna, the second loop antenna set, the third loop antenna, and the fourth loop antenna set. Since the antenna system is used, it is possible to arrange the gate antennas continuously without any gaps, and it is possible to determine which gate antenna the transponder has passed.
In addition, when switching the group of loop antennas, if the process of shifting the frequency of the non-operating loop antenna from the resonance frequency of the responder is performed, interference between the groups of loop antennas can be prevented.

An interrogator system of a reader / writer system according to an embodiment of the present invention includes a first loop antenna, a second loop antenna, a third loop antenna, a distributor / synthesizer connected to each loop antenna, An antenna switch that is connected to the distributor / synthesizer and switches between a set of the first loop antenna and the second loop antenna, a set of the second loop antenna and the third loop antenna, and a reader / writer connected to the antenna switch Therefore, it is possible to arrange the gate antennas continuously without gaps, and to determine which gate antenna the responder has passed through.
In addition, when switching the group of loop antennas, if the process of shifting the frequency of the non-operating loop antenna from the resonance frequency of the responder is performed, interference between the groups of loop antennas can be prevented.

An interrogator system of a reader / writer system according to an embodiment of the present invention includes a first loop antenna, a second loop antenna, a third loop antenna, a fourth loop antenna, and a first loop antenna. And a first distributor / synthesizer connected to the second loop antenna, a second distributor / synthesizer connected to the third loop antenna and the fourth loop antenna, and a first distributor / synthesizer The first reader / writer and the second reader / writer connected to the second distributor / synthesizer, the first reader / writer and the second reader / writer are connected, and the first reader / writer is A set of the first loop antenna and the second loop antenna is selected in a specific time zone, and the second reader / writer selects a set of the third loop antenna and the fourth loop antenna in a time zone other than the above time zone. Interrogator system to choose Since a, can be arranged in succession gate antenna without gaps, which as it can determine further the responder passes between which the gate antennas.
Note that, when selecting a set of loop antennas, interference between the sets of loop antennas can be prevented by performing processing for shifting the frequency of the non-operating loop antenna from the resonance frequency of the responder.

The interrogator system of the reader / writer system according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of an interrogator system of a reader / writer system according to a first embodiment of the present invention.
The interrogator system (first system) of the reader / writer system according to the first embodiment of the present invention is connected to a plurality of loop antennas 1a to 1d and loop antennas 1a and 1b as shown in FIG. Distributor / synthesizer 3a, distributor / synthesizer 3b connected to loop antennas 1c and 1d, antenna switcher 6 connected to distributor / synthesizer 3a and distributor / synthesizer 3b to switch antennas, and antenna switcher And a reader / writer (interrogator) 4 connected to 6.
In FIG. 1, four loop antennas 1 a to 1 d are shown for simplicity of explanation, but a system including a larger number of loop antennas 1 and distributors / combiners 3 may be used.

Two loop antennas (for example, loop antennas 1a and 1b or loop antennas 1c and 1d) constitute a gate antenna that detects the responder.
The gate antenna continues to issue a command to the responder that passes through the detection area between the loop antennas, and receives a response signal from the responder when the responder passes.

  The distributor / combiner 3 distributes the signal output from the reader / writer 4 via the antenna switch 6 to each loop antenna 1 and combines the signal from the responder 10 received by the loop antenna 1 to combine the signal with the antenna switch. 6 is output.

The antenna switch 6 operates in a time-sharing manner, and assigns time slots equal to or greater than the number of the distributor / combiners 3 to be connected to the distributor / combiner 3.
Specifically, as illustrated in FIG. 1, since the two distributors / combiners 3a and 3b are connected to the antenna switch 6, the time slot A is assigned to the distributor / combiner 3a and the time slot B is distributed. / Assign to synthesizer 3b. In other words, the distributor / synthesizer 3a and the reader / writer 4 are connected in the time zone of slot A, and the distributor / synthesizer 3b and the reader / writer 4 are connected in the time zone of slot B.
Thus, by performing time-division control with the antenna switch 6, interference between adjacent gate antennas can be reduced.

  The reader / writer 4 is connected to the antenna switch 6 in a time-sharing manner, takes a signal from the antenna switch 6 in a time-sharing manner, and is a gate antenna composed of the loop antennas 1a and 1b and a gate antenna composed of the loop antennas 1c and 1d. The passage of the responder 10 is recognized.

Further, when a plurality of loop antennas 1 are arranged, if antennas are arranged close to each other, even a non-operating antenna may receive a magnetic field from an operating antenna and malfunction.
Therefore, in the first system, the gate antenna selected by the time division control is set to a frequency that resonates with the operating frequency of the responder 10, but the process of shifting the resonance frequency is intentionally performed for the gate antenna that is not selected.
For this purpose, the setting of the drive frequency (resonance frequency) in the gate antenna 1 is changed to a frequency shifted from the normal resonance frequency in conjunction with the time division control of the antenna switch 6.
The process of shifting the resonance frequency may be performed by the reader / writer 4 or may be performed by another control unit.

Next, an interrogator system of a reader / writer system according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic configuration diagram of an interrogator system of a reader / writer system according to the second embodiment of the present invention.
As shown in FIG. 2, the interrogator system (second system) of the reader / writer system according to the second embodiment of the present invention is connected to a plurality of loop antennas 1e, 1f, 1g and all these loop antennas. A distributor / synthesizer 3, an antenna switching unit 6 connected to the distributor / synthesizer 3 to switch antennas, and a reader / writer 4.

In the second system, the gate antenna includes a loop antenna 1e and a loop antenna 1f, and another gate antenna includes a loop antenna 1f and a loop antenna 1g.
That is, the loop antenna 1f is a shared antenna for two adjacent gate antennas.

All the loop antennas 1 are connected to the distributor / synthesizer 3, and a number of wires one less than the number of connected loop antennas is connected to the antenna switch 6.
Specifically, as shown in FIG. 2, signals from the loop antenna 1e and the loop antenna 1f are combined and output to the antenna switch 6 via the left wiring in the figure, and the loop antenna 1f and the loop antenna are also output. The signals from 1g are combined and output to the antenna switch 6 via the right wiring in the figure.
That is, the signal output from the loop antenna 1f is distributed to the left wiring and the right wiring in the drawing.

  Similarly to the first system, the antenna switch 6 performs time-sharing control, connects the gate antenna including the loop antennas 1e and 1f and the reader / writer 4 in a specific slot, and loop antennas 1f and 1f in another slot. A 1 g gate antenna and a reader / writer 4 are connected.

  Similar to the first system, the reader / writer 4 is connected to the antenna switcher 6 in a time division manner, takes in the signal from the antenna switcher 6 in a time division manner, and includes a gate antenna and a loop antenna made up of the loop antennas 1e and 1f. It recognizes the passage of the responder 10 in the gate antenna composed of 1f and 1g.

  In the second system, although depending on the power supplied to the gate antenna, a process of shifting the resonance frequency is performed for the non-operating antenna as in the first system. However, when the distance between the loop antennas is sufficiently large, it is not necessary to shift the resonance frequency.

  In the first and second systems, the function of the antenna switcher may be incorporated in the reader / writer 4.

Next, an interrogator system of a reader / writer system according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic configuration diagram of an interrogator system of a reader / writer system according to the third embodiment of the present invention.
As shown in FIG. 3, the interrogator system (third system) of the reader / writer system according to the third embodiment of the present invention includes a plurality of loop antennas 1a, 1b, 1c, 1d, a loop antenna 1a, A distributor / synthesizer 3a connected to 1b, a distributor / synthesizer 3b connected to the loop antennas 1c and 1d, a reader / writer 4a connected to the distributor / synthesizer 3a, and a reader / writer 4b connected to the distributor / synthesizer 3b. And a reader / writer synchronization signal cable (control cable) 7 for connecting both reader / writers.

The loop antennas 1a, 1b, 1c, 1d and the distributor / synthesizers 3a, 3b in the third system are the same as those in the first system.
In the third system, reader / writers that individually control gate antennas are connected to each other by a control cable 7 without using an antenna switcher, and mutually monitor the state or operate in accordance with a synchronization signal. Thus, the individual gate antennas are time-division controlled to determine the passage between the responder gate antennas.

  In other words, the third system has n units in which two pairs of loop antennas are connected to the reader / writer via the distributor / synthesizer.

  In the third system as well, as in the first system, the gate antenna selected by the time division control is set to a frequency that resonates with the operating frequency of the responder 10, but the process of shifting the resonance frequency is performed for a gate antenna that is not selected. Is done intentionally.

  In the first to third systems, the reader / writer 4 outputs a response to the connected alarm device (buzzer, satellite, etc.) to generate an alarm.

  According to the first to third systems, while selecting the gate antenna in time division, the selected gate antenna is set to a frequency that resonates with the transponder, but the frequency of the unselected gate antenna is shifted. Thus, the transponder can be detected without interference between the gate antennas, the gate antennas can be continuously arranged without a gap, and further, it is possible to determine which gate antenna the transponder has passed.

  INDUSTRIAL APPLICABILITY The present invention is suitable for an interrogator system of a reader / writer system in which gate antennas can be continuously arranged without a gap, and further, which gate antenna the responder has passed can be determined.

It is a schematic block diagram of the interrogator system of the reader / writer system according to the first embodiment of the present invention. It is a schematic block diagram of the interrogator system of the reader / writer system which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the interrogator system of the reader / writer system which concerns on the 3rd Embodiment of this invention. It is a schematic block diagram of a basic reader / writer system. It is a schematic block diagram at the time of arrange | positioning multiple gate antennas. It is a schematic block diagram in the case where a plurality of gate antennas are arranged and the distributor / combiner is combined in multiple stages.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Loop antenna, 3 ... Distributor / synthesizer, 4 ... Reader / writer (interrogator), 5 ... Shield plate, 6 ... Antenna switch, 7 ... Control cable, 10 ... Responder

Claims (1)

An interrogator system for a reader / writer system that detects passage of a responder,
A first loop antenna, a second loop antenna, and a third loop antenna;
A distributor / synthesizer connected to each loop antenna;
An antenna switch that connects to the distributor / synthesizer and switches between a first loop antenna and a second loop antenna set, and a second loop antenna and a third loop antenna set;
An interrogator system comprising a reader / writer connected to an antenna switch.

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