JP2003283367A - Interrogation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enlarge the region in which communication is possible by an interrogator (reader/writer) without causing interference, omission of detection and slowdown of the processing speed. <P>SOLUTION: The interrogation system performs radio communication of the same signals by several interrogators with a moving responding device (IC card) 1. Several interrogators 4A-4C are provided in such a way that the regions in which communication is possible by antennas 6A-6C are overlapping for enlarging the region in which communication is possible. By synchronizing the transmission/reception by the antennas of the interrogators, interference such as reception by an interrogator of signals transmitted by another interrogator can be prevented. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interrogator system in which an interrogator that wirelessly communicates with a movable transponder (mobile information communication body) is provided by overlapping the communicable areas of a plurality of antennas. The present invention relates to a technique for preventing interference between antennas of a container.

[0002]

2. Description of the Related Art Movable transponders such as IC cards and ID tags have been widely put into practical use, and by performing wireless communication with an interrogator called a reader / writer or the like,
A system for exchanging various kinds of information recorded in a memory of a responder with an interrogator has been realized.

For example, an IC card constructed by embedding a microcomputer chip and a memory chip in a card substrate of the same size as a credit card is used for finance, distribution,
Practical applications are being made in various fields such as transportation and medical care. In an IC card system using such an IC card, for example, power is transmitted and supplied from the reader / writer to the IC card, and information is communicated between the reader / writer and the IC card by non-contact wireless communication.

The ID tag simplifies the function of the IC card,
As a tag shape that can be easily attached to an article, it is used for delivery management of the article in a physical distribution system, for example. Since other transponders such as ID tags are similar to IC cards, these responders will be collectively referred to as IC cards and will be described below.

Further, the reader / writer uses a radio signal (radio wave).
For transmitting and receiving antennas, radio wave power supply and transmission function for wirelessly transmitting power and information from the antenna to the IC card,
It is provided with a data receiving function of receiving information wirelessly transmitted from the C card by an antenna. On the other hand, the IC card stores an antenna for transmitting and receiving radio signals, a function of receiving power and information wirelessly transmitted from the reader / writer by the antenna, a function of wirelessly transmitting information from the antenna to the reader / writer, identification information, and the like. It is equipped with a memory.

Radio communication between the reader / writer and the IC card is performed in a half-duplex system. That is, as shown in FIG. 5, the reader / writer transmits the inquiry information (transmission time), and the IC card returns the information stored in the memory in response to the inquiry information (reception time). Information communication is done. When the reader / writer receives the information from the IC card, the reader / writer executes other processing such as processing of the information.

[0007]

Here, there is a limit to the size of the wireless communication area of the reader / writer due to the regulations of the Radio Law and radio wave protection guidelines considering the influence of radio waves on the human body. On the other hand, for example, in order to surely detect an IC card that a user carries and moves, or an IC card that is attached to an article and moves on a conveyor to perform information communication, a wireless communication area of the reader / writer is set. It is required to expand. In response to such a request, as shown in FIG. 6, a plurality of reader / writers A, B, and C, which perform the same question processing for the IC card, are installed adjacent to each other, and the communication area a of these reader / writers a , B, and c may be overlapped to expand the area that can communicate with the IC card 1. That is, these communicable areas a,
In either case of b or c, wireless communication with the IC card 1 is enabled.

However, when a plurality of reader / writers A, B, and C are installed with their communication areas overlapped with each other, the following problems occur. For example, when the IC card 1 is located at the overlapping position of the communicable area a of the reader / writer A and the communicable area b of the reader / writer B, the communication timing between the reader / writer A and the reader / writer B is set as shown in FIG. If there is a gap between the two, reader / writer A
Due to the interference between the reader / writer B and the reader / writer B, a reception error of the response information from the IC card occurs in the reader / writer A.

More specifically, the output of the IC card is not so large as compared with the reader / writer (for example,
Since the difference is about 1000 to 100,000 times), while the reader / writer A transmits the question information to the IC card (A system transmission time) and receives the response information (A system reception time)
Then, the reader / writer B sends question information (B system transmission time)
Therefore, the question information from the reader / writer B is received by the reader / writer A receiving the response information from the IC card, and the reception circuit of the reader / writer A causes a reception error due to the mixing of large noise. I will end up.

To solve such a problem, as shown in FIG. 8, a method of setting the communication timings of the reader / writers A, B, and C so that they do not overlap each other can be considered. That is, while one adjacent reader / writer is transmitting / receiving, another reader / writer is not transmitting / receiving,
Avoid receiving the transmission signals of other reader / writers.

However, since the reader / writer sequentially performs communication, it cannot be said that the communicable area is expanded at the same point, and a moving IC card may not be detected. Specifically, when the IC card moves in the direction opposite to the communication switching order of the reader / writer, or when the IC card moves at a high speed on the conveyor, no reader / writer can detect the IC card. Will end up. Further, the communication process (A system to C system) of each reader / writer A to C takes one turn, but the next question information cannot be transmitted unless these communication processes are completed, so the communication process is generally performed. The speed will decrease.

The present invention has been made in view of the above-mentioned conventional circumstances, and it is possible to expand a communicable area by a reader / writer (interrogator) without causing the above-mentioned interference, omission of detection, and reduction in processing speed. With the goal. A further object of the present invention will be apparent from the description below.

[0013]

SUMMARY OF THE INVENTION The present invention is an interrogator system in which an interrogator wirelessly communicates with a movable transponder, and a plurality of interrogators are provided so that the communicable areas of antennas are overlapped. Furthermore, the transmission / reception by the antenna of each interrogator is synchronized. Therefore, since a plurality of interrogators perform transmission and reception at the same time, a truly expanded communicable area is formed in which the same question information is simultaneously sent to these communicable areas. Since the transmission signal of the interrogator is not received, the transponder can be surely detected. Further, since the communication processing turn by each interrogator ends at the same time, the next inquiry information can be transmitted quickly, and the communication processing speed is improved.

Further, the present invention is an interrogator system in which an interrogator wirelessly communicates with a movable transponder. A plurality of antennas are provided in one interrogator, and communicable areas of these antennas are overlapped. Further, the interrogator synchronizes transmission and reception by each antenna. That is,
Whereas the above invention expands the coverage area by providing a plurality of interrogators, the present invention expands the coverage area by providing a plurality of antennas.

When a plurality of antennas are provided in one interrogator in this way, the output is distributed to each antenna, so the output of the interrogator must be increased. At present, it may not be possible to set the output of the interrogator to a required level at a large level due to regulations such as the Radio Law, but this can be achieved by deregulation and implementation in a special environment where radio waves do not leak. The above-described invention in which a plurality of interrogators are provided can be said to be advantageous in this respect because the communicable area can be expanded as a whole even if the interrogator output is small.

Further, according to the present invention, the plurality of antennas can be set such that their directivity directions are different from each other. I
Generally, a responder such as a C card has a loop antenna and the like and has a strong directivity in the vertical direction of the card. Therefore, depending on the orientation of the responder, detection by an interrogator may be difficult. On the other hand, because multiple antennas are installed in various pointing directions, when the transponder passes through the communication range of these antennas, the interrogator can accurately detect whichever direction the transponder is. Can communicate.

An invention in which the communication timing between reader / writers is shifted in order to prevent interference between adjacent interrogators (JP-A-11-102419 and JP-A-2000).
No. 242742 and Japanese Patent Laid-Open No. 2000-268140), and inventions using different frequencies (Japanese Patent Laid-Open No. 5-217032, 2000).
No. 20651) has been proposed, but neither of them is intended to expand the communicable area by synchronizing the timing of transmission / reception processing between reader / writers (antennas), and is a technical idea different from the present invention. is there.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described based on Examples. FIG. 1 shows a reader / writer (interrogator) system according to a first embodiment of the present invention. In this example, an IC card (responder) is attached to the article 3 conveyed by the conveyor 2.
1 is attached and the present invention is applied to a physical distribution system for reading information such as an identification number, a product delivery destination, and a product name recorded on the IC card 1 as a response signal.

In this example, three reader / writers 4A, 4A, 4
B and 4C are provided, and the reader / writer 4A to
4C is integrally controlled by the control terminal 5. The reader / writers 4A are installed on the upper and lower sides of the conveyor 2, respectively.
It has one antenna 6A, and these antennas 6A are connected to the reader / writer 4A via a distributor / combiner 7A. The reader / writer 4B has two antennas 6B installed on the left and right sides of the conveyor 2, and these antennas 6B are connected to the reader / writer 4B via a distributor / combiner 7B.
It is connected to the. The reader / writer 4C has an annular antenna 6C, and the conveyor 2 penetrates the center of the antenna 6C.

That is, the antenna 6C is omnidirectional and transmits the inquiry information to the IC card 1 on the conveyor 2 from all directions, while the antenna 6A transmits the inquiry information to the IC card 1 on the conveyor 2 from above and below. The antenna 6
B transmits the question information to the IC card 1 on the conveyor 2 from the left and right directions, so that the directivity is different. Further, as shown in FIG. 6, the communicable areas of the antennas 6A and 6B are partially overlapped with each other, and the communicable areas of the antennas 6B and 6C are partially overlapped with each other. By ~ 6C, a communicable area expanded in the longitudinal direction along the conveyor 2 is formed.

Each reader / writer 4A-4C is provided with a synchronizing circuit 8 as shown in FIG. 2, and all the reader / writers 4 respond in response to a synchronizing signal t input from the control terminal 5.
A to 4C perform communication processing in synchronization with each other as shown in FIG.
The synchronizing circuit 8 responds to the synchronizing signal t by controlling the control terminal 5
The parallel transmission data input from the antenna is converted into serial data and wirelessly transmitted as a modulated signal output from the antenna. The synchronization signal t defines the transmission timing from the antenna. As shown in FIGS. 3 and 5, in this example, the receiving process and other processes are set to be executed subsequent to the transmitting process. Therefore, by synchronizing the transmitting timing, the subsequent receiving timing is also set. It will be synchronized. Of course, in the present invention, the synchronization may be achieved by another known method.

The transmission / reception timing will be described in more detail with reference to FIG. Note that the transmission / reception processing timing of the reader / writer 4A is shown as an A system, the transmission / reception processing timing of the reader / writer 4B is shown as a B system, and the transmission / reception processing timing of the reader / writer 4C is shown as a C system. Reader / Writer 4A-4
C responds to the synchronization signal t by wirelessly transmitting the same inquiry information from the antenna (transmission time), and subsequently, at the same timing, receives the response signal from the IC card 1 (reception time), Perform other processing (other processing time). That is, all the reader / writers 4A to 4C synchronously transmit the inquiry signal, and synchronously receive the response signal from the IC card 1.

Therefore, according to the reader / writer system described above, the antenna 6A is conveyed by the conveyor 2.
6A to 6C, all the antennas 6A to 6A for the article 3 (IC card 1) passing through the communicable area.
At the same time, an inquiry signal is transmitted from C, and in response to this, the IC
The response signal transmitted from the card 1 is received by the antenna at a position where communication is possible at that time and processed by the reader / writer to which the antenna is connected.

That is, an IC that moves by the expanded communicable area formed by the antennas 6A to 6C.
It is possible to communicate with the card without omission, and moreover, highly accurate communication is realized without receiving a transmission signal of another reader / writer and causing a reception error. Further, in this example, since the pointing directions of the antennas 6A to 6C are different,
Whatever direction the IC card 1 is attached to the article 3, the IC card can be detected by any reader / writer, and omission of detection can be prevented.

FIG. 4 shows a reader / writer system according to a second embodiment of the present invention. In the first embodiment, a plurality of reader / writers are provided adjacent to each other.
Since a plurality of antennas adjacent to each other are connected to the reader / writer 4 of the table, in the description of the present example, the same parts as those in the first embodiment are designated by the same reference numerals and the duplicate description will be omitted.

In this example, one reader / writer 4 is provided with two antennas 16 installed above and below the conveyor 2, respectively.
A, two antennas 16B respectively installed on the left and right sides of the conveyor 2, and an annular antenna 16C penetrating the conveyor 2 are provided. Connected, antenna 1
6A is connected to the reader / writer 4 via the three-division combiner 15 and the distribution-combiner 17A, and the antenna 16B is connected to the reader-writer 4 via the three-division combiner 15 and the distribution-combiner 17B.
It is connected to the.

The antenna 16C is omnidirectional and transmits question information to the IC card 1 on the conveyor 2 from all directions, while the antenna 16A transmits question information to the IC card 1 on the conveyor 2 from above and below. However, the directivity of the antenna 16B is different from that of the IC card 1 on the conveyor 2 so that the question information is transmitted from the left and right directions. Further, as shown in FIG. 6, the communicable areas of the antennas 16A and 16B are partially overlapped with each other, and the communicable areas of the antennas 16B and 16C are partially overlapped with each other. By ~ 16C, a communicable area expanded in the longitudinal direction along the conveyor 2 is formed.

In this example, since there is one reader / writer, it is not necessary to provide the synchronizing circuit 8 as shown in FIG. 2 in order to synchronize a plurality of reader / writers, and the control terminal 5 is synchronized. It is not necessary to supply a signal, the antenna 16
Transmission / reception processing is simultaneously performed by A to 16C. Therefore, the transmission / reception processing by all the antennas 16A to 16C is synchronously performed as shown in FIG.

Therefore, according to the reader / writer system described above, the antenna 16 is conveyed by the conveyor 2.
All the antennas 16 for the article 3 (IC card 1) passing through the communicable area formed by A to 16C.
The inquiry signals are simultaneously transmitted from A to 16C, and the response signal transmitted from the IC card 1 in response to the inquiry signals is received by the antenna at the position where communication is possible at that time and processed by the reader / writer 4.

That is, the antennas 16A to 16A do not cause reception errors due to interference with other reader / writers.
The expanded communicable area formed by C makes it possible to communicate with a moving IC card without omission, and the antennas 16A to 16C have different pointing directions. Even if the IC card is attached in the direction, the IC card can be detected by any of the antennas 16A to 16C, and the omission of detection can be prevented.

In the above description, an example in which three reader / writers or three antennas are provided has been shown, but it is sufficient if the number is two or more because the communicable area can be expanded. Also, multiple antennas do not necessarily have to have different directivities,
For example, when expanding the communicable area in the same direction, a plurality of antennas may be provided adjacent to each other in the same direction, and which antenna to use may be selected according to the necessity of implementation. Further, in the above description, an example in which the IC card is operated by wirelessly transmitting power from the reader / writer to the IC card has been shown, but a power source such as a battery may be provided inside the IC card. In such a case, it is not always necessary to wirelessly transmit power from the reader / writer.

[0032]

As described above, according to the interrogator system of the present invention, when a plurality of interrogators that wirelessly communicate with a mobile information communication body by their respective antennas are provided so that their communicable areas overlap each other, 2 In one interrogator, the other interrogator is arranged in the communicable area of one interrogator, and the other interrogator comprises means for detecting a signal wirelessly transmitted from the one interrogator using an antenna,
Since the inquiry signal to the mobile information communication body is wirelessly transmitted in response to the detection of the non-signal state by the means, it is performed, for example, between the one interrogator and the mobile information communication body. It is possible to prevent the existing wireless communication from being disturbed, and thus it is possible to ensure that normal information communication is performed between the interrogator and the mobile information communication body.

[Brief description of drawings]

FIG. 1 is a diagram showing an interrogator system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a synchronization circuit.

FIG. 3 is a diagram illustrating an example of synchronization timing according to the present invention.

FIG. 4 is a diagram showing an interrogator system according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating transmission / reception timing of an interrogator.

FIG. 6 is a diagram illustrating expansion of a communicable area by a plurality of interrogators.

FIG. 7 is a diagram illustrating transmission / reception timing of an interrogator.

FIG. 8 is a diagram illustrating transmission / reception timing of an interrogator.

[Explanation of symbols]

1: IC card (responder), 4, 4A, 4B, 4C: reader / writer (interrogator), 6A, 6B, 6C, 16A, 16B, 16C: antenna, 8: synchronization circuit, t: synchronization signal,

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5B058 CA15 KA24 YA20                 5K012 AA03 AB05 AB12 AC06 AC08                       AC10 BA02

Claims (3)

[Claims] 1. An interrogator system in which an interrogator wirelessly communicates with a movable transponder, wherein a plurality of interrogators are provided with overlapping antenna communicable areas, and further, transmission / reception by an antenna of each interrogator. An interrogator system characterized by synchronizing the interrogators. 2. An interrogator system in which an interrogator wirelessly communicates with a movable responder, wherein one interrogator is provided with a plurality of antennas, and communicable areas of these antennas are overlapped and arranged. Furthermore, the interrogator is an interrogator system characterized by synchronizing transmission and reception by each antenna. 3. The interrogator system according to claim 1 or 2, wherein a plurality of antennas have different directivity directions.