JP2009089163A - Reader/writer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reader/writer which can reliably and accurately read and write information recorded in an RF tag attached to a mobile body surface. <P>SOLUTION: The arrangement 100 is composed of a rotating body 35 rotating in a direction of an arrow 37 around a central axis 36, an RF tag 40 attached on a surface of the rotating body 35, an antenna 9 receiving information recorded in the RF tag 40, and a reader/writer 30 reading/writing the information of the RF tag 40 through the antenna 9. The antenna 9 is composed of two loop antennas which are not shown. When a synthetic magnetic field is generated by supplying a reverse phase signal to the respective loop antennas, the loop antennas are arranged so that the synthetic magnetic field intersects with the RF tag 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reader / writer, and more particularly, to a reader / writer suitable for reading and writing information of an IC tag attached to a moving body, particularly a rotating body.

  In recent years, new information recording media called IC cards are widely available on the market. An IC card is a generic name for a readable / writable recording medium that has a card-like or sheet-like shape such as a credit card, bank card, point card, etc., and has an IC incorporated in the card or on the card surface. . In particular, the non-contact type IC card is often used as a commuter pass or a prepaid card used when entering or leaving a station of a transportation facility such as a railway. Further, as a kind of non-contact type IC card, there is an RF (Radio Frequency) tag that is structurally the same as the non-contact type IC card and records management information relating to an identification number and history information. As a type of tag, a non-contact type RF tag (hereinafter simply referred to as an RF tag) used for classifying and managing mail items or packages is known.

In a conventional reader / writer using a loop antenna, the communication distance between the RF tag and the RF antenna is remarkably different when there is an object that shields a magnetic field such as metal at the center of the loop antenna or depending on the positional relationship between the loop antenna and the RF tag. There are drawbacks such as degradation or inability to communicate. FIG. 7 is a diagram for explaining an operation of reading and writing information recorded on an RF tag attached to the surface of a rotating body by a reader / writer using a conventional loop antenna. As shown in FIG. 7, as the rotational speed of the cylinder 120 increases, the time for which the loop antenna 110 and the RF tag 130 face each other is shortened. Therefore, the communication processing time between the reader / writer 100 and the RF tag 130 is insufficient. Abnormality is likely to occur. In particular, when the column 120 is made of metal, it is difficult to continuously identify the RF tags 130 on the column.
Patent Document 1 discloses a management system for a moving body that receives information on an RF tag embedded in a wheel by an antenna installed on the ground.
JP 2006-213523 A

However, the conventional technique disclosed in Patent Document 1 cannot read information recorded on the RF tag until the RF tag embedded in the wheel approaches the antenna installed on the ground. There is a problem that it takes time, and a moving distance when the RF tag makes one rotation differs depending on the size of the wheel. When the wheel diameter increases, there is a problem that the size of the antenna must be increased.
The present invention has been made in view of such problems, and each loop antenna is arranged so that a combined magnetic field generated by two loop antennas always crosses the RF tag even when the RF tag moves. Accordingly, an object of the present invention is to provide a reader / writer that can reliably and accurately read and write information recorded on an RF tag attached to a moving body.

In order to solve this problem, the present invention provides a reader / writer including an antenna for reading and writing information recorded on a moving non-contact information recording medium, wherein the antenna includes at least two loop antennas. Each of the loop antennas is arranged so that the combined magnetic field intersects the non-contact information recording medium when a combined magnetic field is generated by supplying an antiphase signal to each loop antenna. Features.
When the non-contact information recording medium is moving, information may not be read correctly depending on the moving speed. Therefore, in the present invention, the antenna is configured by two loop antennas, and signals of opposite phases are supplied to the respective loop antennas so that the directions of the magnetic fields generated from the respective loop antennas are the same. To do. Each loop antenna is arranged so that the combined magnetic field intersects the non-contact information recording medium. Thereby, the information recorded on the moving non-contact information recording medium can be always read and written accurately.

The second aspect of the present invention provides the loop antenna according to claim 1, wherein the loop antenna is connected to the circumferential surface of the rotating body in order to read and write information recorded on the non-contact information recording medium attached to the circumferential surface of the columnar rotating body that rotates about the central axis. The combined magnetic field generated from each loop antenna intersects with the non-contact information recording medium.
The present invention relates to the case of reading and writing information recorded on a non-contact information recording medium attached to a rotating body. In particular, the present invention relates to a case where reading / writing is performed on a non-contact information recording medium attached to a peripheral surface of a columnar rotating body. In other words, when a non-contact information recording medium is attached to the peripheral surface of the rotating body, when attempting to read / write information from one direction, if the rotating body is made of metal or the rotation speed is high, the information is read / written correctly. An impossible situation occurs. Therefore, in the present invention, the two loop antennas are arranged so as to face the peripheral surface of the rotating body in a non-contact state, and the loop antennas are arranged so that the combined magnetic field generated by each loop antenna intersects the non-contact information recording medium. To do. Thereby, information can be always read and written regardless of the speed of the rotating body and the position of the non-contact information recording medium.

According to a third aspect of the present invention, in order to read and write information recorded on the non-contact information recording medium attached to the surface of the rotating body that rotates about the central axis, the loop antennas are concentric with the central axis. The combined magnetic field generated by each loop antenna intersects with the non-contact information recording medium.
The present invention relates to the case of reading and writing information recorded on a non-contact information recording medium attached to a rotating body. In particular, the present invention relates to a case where a non-contact information recording medium is attached to the surface of a rotating body that rotates about a central axis. That is, when a non-contact information recording medium is attached to the surface of the rotator, when information is read / written from one place, a situation in which information cannot be correctly read / written occurs when the rotation speed is high. Therefore, in the present invention, the two loop antennas are arranged concentrically with respect to the central axis so as to be opposed to the rotating body so that the combined magnetic field generated by each loop antenna intersects the non-contact information recording medium. Arrange each loop antenna. Thereby, information can be always read and written regardless of the speed of the rotating body and the position of the non-contact information recording medium.

According to a fourth aspect of the present invention, in order to read and write information recorded on the non-contact information recording medium attached to a moving body that moves in a fixed direction or reciprocates, the respective loop antennas are arranged in parallel with the moving body. The synthetic magnetic fields generated by the loop antennas are spaced apart from each other and intersect with the non-contact information recording medium.
The present invention relates to a case of reading and writing information recorded on a non-contact information recording medium attached to a moving body that moves in a fixed direction or reciprocates. In particular, the present invention relates to a case where a non-contact information recording medium is attached to a moving body that moves in a certain direction, such as a belt conveyor, or a moving body that reciprocates within a predetermined range. In other words, when a non-contact information recording medium is attached to a moving body, when trying to read / write information from one place, if the non-contact information recording medium moves out of the communicable range, a situation where information cannot be read / written correctly occurs. . Therefore, in the present invention, two loop antennas are arranged in parallel to be spaced apart from the moving body, and each loop antenna is arranged so that the combined magnetic field generated by each loop antenna intersects the non-contact information recording medium. . Thereby, information can be always read and written regardless of the speed of the moving body and the position of the non-contact information recording medium.

According to a fifth aspect of the present invention, when the rotating body or the moving body is made of a metal, a ferrite or a spacer is interposed between the non-contact information recording medium and the metal.
When a non-contact information recording medium is attached in close contact with metal, the magnetic field intersecting the non-contact information recording medium is attenuated by the metal, and information cannot be read or written. Therefore, in the present invention, the non-contact information recording medium and the metal are attached via a ferrite or a spacer. Thereby, a magnetic field loop intersecting with the non-contact information recording medium is formed, and information can be read and written correctly.

According to the present invention, the antennas are composed of two loop antennas, and signals of opposite phases are supplied to the respective loop antennas so that the directions of the magnetic fields generated from the respective loop antennas are the same. Since each loop antenna is arranged such that the combined magnetic field intersects the non-contact information recording medium, information recorded on the moving non-contact information recording medium can always be read and written accurately.
In addition, since the two loop antennas are arranged facing each other in a non-contact state with the peripheral surface of the rotating body, and each loop antenna is arranged so that the combined magnetic field generated by each loop antenna intersects the non-contact information recording medium, Information can always be read and written regardless of the speed of the rotating body and the position of the non-contact information recording medium.

Further, the two loop antennas are arranged concentrically with respect to the central axis so as to face each other apart from the rotating body, and each loop antenna so that the combined magnetic field generated by each loop antenna intersects the non-contact information recording medium. Therefore, information can be always read and written regardless of the speed of the rotating body and the position of the non-contact information recording medium.
Further, two loop antennas are arranged in parallel so as to face each other and move away from a moving body that moves in a certain direction or reciprocates, and each loop so that the combined magnetic field generated by each loop antenna intersects the non-contact information recording medium. Since the antenna is arranged, information can be read and written at all times regardless of the speed of the moving body and the position of the non-contact information recording medium.
Further, since the non-contact information recording medium and the metal are attached via a ferrite or a spacer, a magnetic field loop intersecting with the non-contact information recording medium is formed, and information can be read and written correctly.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
FIG. 1 is a block diagram showing the configuration of the reader / writer of the present invention. The reader / writer 30 is controlled by a PC 50 that exchanges data with the reader / writer 30 and controls the entire system. The reader / writer 30 includes the transmission / reception device 1 that controls the communication protocol of data with the external PC 50, the control device 2 that controls the operation of the reader / writer 30 as a whole, and firmware that records the procedure for operating the control device 2 and the read data A memory device 3 for storing data, a modulator 4 for modulating data from the control device 2 on a carrier wave, an input device 5 for inputting an operation command, and a display device 6 for displaying information controlled by the control device 2 A power amplifier 7 that amplifies the power supply signal that is an AC signal from the control device 2 and a write command from the modulator 4, and a detector demodulator that converts the carrier wave received from the loop antenna 9 into binary data 8 and a loop antenna 9 for exchanging power and data with an IC card (RF tag) (not shown). The loop antenna 9 includes a loop antenna 9a that supplies signals having opposite phases and a loop antenna 9b.

  Next, before describing the operation of the reader / writer 30 according to this configuration, the configuration of the IC card (RF tag) will be described first. FIG. 2 is a block diagram showing a configuration of a general IC card (RF tag). The IC card (RF tag) 40 of this embodiment includes an antenna 20 that transmits and receives data using a power carrier wave from the reader / writer 30, a transmission / reception circuit 21 that generates a write command read command, and a power carrier wave from the antenna 20. Power generation circuit 22 that rectifies and converts it into DC power, a memory device 23 that manages storage of control firmware and data, and a modulator 24 that modulates a transmission command from the control circuit 26 with a carrier wave. And a detector 25 for converting carrier wave data from the transmission / reception circuit 21 into binarized data, and a control circuit 26 for controlling the overall operation of the IC card (RF tag) 40.

Next, each operation will be described with reference to FIGS. 1 and 2 together. When a power supply (not shown) is turned on, the reader / writer 30 starts an operation according to a program stored in the memory device 3 after the initial operation of the control device 2. First, initialization is performed. Next, the control device 2 alternately transmits a power supply signal supplied to the IC card (RF tag) 40 and a polling signal from the power amplifier 7. The signal is radiated to the outside from the loop antenna 9 as an electromagnetic wave. Next, when the IC card (RF tag) 40 comes close to the reader / writer 30, the antenna 20 receives the power supply signal, rectifies the carrier wave by the power generation circuit 22 and converts it into DC power, and then in the RF tag. To all circuits. When power is supplied and the control circuit 26 is driven, control is started in accordance with a program stored in the memory device 23.
Next, the control circuit 26 first demodulates the command from the transmission / reception circuit 21 by the detector 25 and converts it into a binary signal, and analyzes the command. As a result, when it is recognized that it is called, the response is modulated by the modulator 24 and transmitted from the antenna 20 via the transmission / reception circuit 21. The response is received by the reader / writer 30 with the loop antenna 9, converted into a binary code by the detector demodulator 8, analyzed by the control circuit 2, and the IC card (RF tag) 40 conforms to the standard IC card ( RF tag). Thereby, polling is performed between the reader / writer 30 and the IC card (RF tag) 40 thereafter. Hereinafter, the IC card (RF tag) 40 is simply referred to as an RF tag 40.

FIG. 3 is a diagram for explaining the outline of the operation of reading and writing information recorded on the RF tag attached to the rotating body by the reader / writer of the present invention. The same components will be described with the same reference numerals as those in FIGS. This configuration 100 is recorded on the rotating body 35 that rotates in the direction of the arrow 37 around the central axis 36, the RF tag (non-contact information recording medium) 40 attached to the circumferential surface of the rotating body 35, and the RF tag 40. It comprises an antenna 9 that receives the received information, and a reader / writer 30 that reads and writes information on the RF tag 40 via the antenna 9. The antenna 9 includes two loop antennas (not shown) (details will be described later). When a combined magnetic field is generated by supplying signals of opposite phases to the respective loop antennas, the combined magnetic field is combined with the RF tag 40. Place the loop antennas so that they intersect. As apparent from FIG. 3, even when the RF tag 40 rotates, the reader / writer 30 can always read and write information from and to the RF tag 40 via the antenna 9 because the antenna 9 always faces the antenna 9. it can. In addition, information can be read from and written to the RF tag 40 regardless of the rotational speed of the rotating body 35.
That is, when the RF tag 40 is rotated (moved), a situation occurs in which information cannot be read correctly due to the rotation speed. Therefore, in the present invention, the antenna 9 is composed of two loop antennas, and signals of opposite phases are supplied to the respective loop antennas so that the directions of the magnetic fields generated from the respective loop antennas are the same. The magnetic field 43 is used (see FIG. 4B). Each loop antenna is arranged so that the synthetic magnetic field 43 intersects the antenna 20 of the RF tag 40. Thereby, the information recorded on the rotating RF tag 40 can be always read and written accurately.

  FIG. 4 is a diagram for explaining the configuration of FIG. 3 according to the first embodiment of the present invention in more detail. 4A is a diagram showing the overall configuration, and FIG. 4B is an enlarged cross-sectional view of a portion A in FIG. 4A. In the configuration 100 of FIG. 4A, each loop antenna 9a, 9b is used to read and write information recorded on the RF tag 40 attached to the peripheral surface of the columnar rotating body 35 that rotates about the central axis 36. In a non-contact manner with the peripheral surface of the rotating body 35, and the combined magnetic field 43 generated by each loop antenna 9a, 9b crosses the antenna 20 of the RF tag 40 (ideally orthogonal). Loop antennas 9a and 9b are arranged. In more detail with reference to FIG. 4B, a signal flows in the direction of the x mark in the loop antenna 9a, and a signal flows in the direction of the mark (that is, currents in opposite directions) through the loop antenna 9b. For example, the magnetic field 41 is generated in the direction of the arrow around the loop antenna 9a. Further, a magnetic field 42 is generated in the direction of the arrow around the loop antenna 9b. Here, the magnetic field 41 and the magnetic field 42 have opposite directions because the directions of the currents are different. In the region P where the magnetic field 41 and the magnetic field 42 intersect, the magnetic field vectors coincide with each other, so that the magnetic field 41 and the magnetic field 42 are combined to generate a combined magnetic field 43. The combined magnetic field 43 intersects with the antenna 20 in the RF tag 40, so that information can be communicated with the reader / writer 30. The RF tag 40 is attached to the rotating body 35 via, for example, a ferrite 44 (or a spacer or the like) so that the magnetic field 41 and the magnetic field 42 form a loop.

In other words, the present embodiment relates to the case of reading and writing information recorded on the RF tag 40 attached to the rotating body 35. In particular, the present invention relates to the case where the RF tag 40 is attached to the peripheral surface of the columnar rotator 35. That is, when the RF tag 40 is attached to the peripheral surface of the rotator 35, when trying to read / write information from one direction, if the rotator 35 is made of metal or the rotation speed is high, the information is read / written correctly. An impossible situation occurs. Therefore, in the present embodiment, the two loop antennas 9a and 9b are disposed to face the peripheral surface of the rotating body 35 in a non-contact state so that the combined magnetic field generated by each loop antenna 9a and 9b intersects the RF tag 40. Each of the loop antennas 9a and 9b is disposed. As a result, information can always be read and written regardless of the speed of the rotator 35 and the position of the RF tag 40.
Moreover, when the rotary body 35 is comprised with the metal, it attaches via the ferrite 44 or a spacer between RF tag 40 and a metal. That is, when the RF tag 40 is attached in close contact with a metal, the magnetic fields 41 and 42 intersecting with the RF tag 40 are attenuated by the metal, and information cannot be read and written. Therefore, in this embodiment, the RF tag 40 and the metal are attached via a ferrite 44 or a spacer. Thereby, the loop of the magnetic fields 41 and 42 which cross | intersect with the RF tag 40 is formed, and information can be read and written correctly. When the rotating body is not metal, the RF tag 40 may be directly attached to the rotating body 35.

FIG. 5 is a diagram for explaining in detail the configuration according to the second embodiment of the present invention. 5A is a diagram showing the overall configuration, FIG. 5B is a side view of FIG. 5A, and FIG. 5C is an enlarged sectional view of a portion B of FIG. 5B. In the configuration 110 of FIG. 5A, in order to read / write information recorded on the RF tag 40 attached to the surface of the rotating body 45 that rotates about the central axis 46, the loop antennas 9a and 9b are centered. It is concentrically arranged with respect to the shaft 46 and is opposed to the rotating body 45 so as to be spaced apart (see FIG. 5B), and the combined magnetic field 49 generated by each loop antenna 9a, 9b is combined with the antenna 20 of the RF tag 40. The loop antennas 9a and 9b are arranged so as to cross each other.
In other words, the present embodiment relates to a case where information recorded on the RF tag 40 attached to the rotating body 45 is read and written. In particular, the present invention relates to the case where the RF tag 40 is attached to the surface of the rotating body 45 that rotates about the central axis 46. That is, when the RF tag 40 is attached to the surface of the rotator 45, if information is to be read / written from one place, a situation in which information cannot be correctly read / written occurs when the rotation speed is high. Therefore, in the present embodiment, the two loop antennas 9a and 9b are arranged concentrically with respect to the central axis 46 so as to be opposed to the rotating body 45 and the combined magnetic field 49 generated by each loop antenna 9a and 9b is generated. The loop antennas 9 a and 9 b are arranged so as to intersect with the antenna 20 of the RF tag 40. Thereby, information can be always read and written regardless of the speed of the rotating body 45 and the position of the RF tag 40. To explain in more detail with reference to FIG. 5C, a signal flows in the direction of the x mark in the loop antenna 9a, and a signal flows in the direction of the mark ● (that is, currents in opposite directions) through the loop antenna 9b. For example, a magnetic field 47 is generated in the direction of the arrow around the loop antenna 9a. A magnetic field 48 is generated in the direction of the arrow around the loop antenna 9b. Here, the magnetic field 47 and the magnetic field 48 have opposite directions because the directions of currents are different. In a region Q where the magnetic field 47 and the magnetic field 48 intersect, the magnetic field vectors coincide with each other, so that the magnetic field 47 and the magnetic field 48 are combined to generate a combined magnetic field 49. The combined magnetic field 49 intersects with the antenna 20 in the RF tag 40, so that information can be communicated with the reader / writer 30. The RF tag 40 is attached to the rotating body 45 via, for example, a ferrite 44 (or a spacer or the like) so that the magnetic field 47 and the magnetic field 48 form a loop.

FIG. 6 is a diagram illustrating in detail the configuration according to the third embodiment of the present invention. 6A is a side view showing the overall configuration, FIG. 6B is a top view of FIG. 6A, and FIG. 6C is an enlarged sectional view of a portion C of FIG. 6B. In the configuration 120 of FIG. 6A, in order to read and write information recorded on the RF tag 40 attached to the belt conveyor (moving body) 52 moving in a fixed direction indicated by an arrow 53, the loop antennas 9a and 9b are respectively read and written. Are arranged in parallel and spaced apart from the belt conveyor 52 so that the combined magnetic field 56 generated by each loop antenna 9a, 9b intersects the antenna 20 of the RF tag 40 (ideally orthogonal). Antennas 9a and 9b are arranged.
That is, the present embodiment relates to the case of reading and writing information recorded on the RF tag 40 attached to the belt conveyor 52 that moves in a certain direction (or reciprocating direction). In particular, the present invention relates to a case where the RF tag 40 is attached to a moving body that moves in a certain direction such as a belt conveyor. That is, when the RF tag 40 is attached to the belt conveyor 52, if information is to be read / written from one place, if the RF tag 40 is moved out of the communicable range, the information cannot be correctly read / written. Therefore, in the present embodiment, the two loop antennas 9a and 9b are arranged in parallel so as to be opposed to the belt conveyor 52 so that the combined magnetic field 56 generated by each loop antenna 9a and 9b intersects the RF tag 40. Each of the loop antennas 9a and 9b is disposed. Thereby, information can be always read and written regardless of the speed of the belt conveyor 52 and the position of the RF tag 40. However, in the case of a belt conveyor, when the RF tag 40 moves to the opposite side after passing through the roller 51, information communication becomes impossible. Further, the present embodiment can cope with reciprocating movement within a predetermined range. In more detail with reference to FIG. 6 (c), a signal flows in the direction of the x mark in the loop antenna 9a, and a signal flows in the direction of the mark ● (that is, currents in opposite directions) through the loop antenna 9b. For example, the magnetic field 54 is generated in the direction of the arrow around the loop antenna 9a. A magnetic field 55 is generated in the direction of the arrow around the loop antenna 9b. Here, the magnetic field 54 and the magnetic field 55 have opposite directions because the directions of currents are different. In the region S where the magnetic field 54 and the magnetic field 55 intersect, the magnetic field vectors coincide with each other, so that the magnetic field 54 and the magnetic field 55 are combined to generate a combined magnetic field 56. The combined magnetic field 56 intersects with the antenna 20 in the RF tag 40, so that information can be communicated with the reader / writer 30. The RF tag 40 is attached to the belt conveyor 52 via, for example, a ferrite 44 (or a spacer) so that the magnetic field 54 and the magnetic field 55 form a loop.

  The above description is an example, and when the RF tag 40 is attached to a moving body (rotation, vibration, movement, etc.), the loop antennas 9a and 9b of the present invention are installed in the moving range of the moving body, and the loop antenna Any moving body may be used as long as the loop antennas 9a and 9b can be arranged so that the synthesized magnetic field synthesized by 9a and 9b intersects the antenna 20 of the RF tag 40.

It is a block diagram which shows the structure of the reader / writer of this invention. It is a block diagram which shows the structure of a general IC card (RF tag). It is a figure explaining the outline of the operation | movement which reads / writes the information recorded on the RF tag attached to the rotary body by the reader / writer of this invention. 3A and 3B are diagrams for explaining the configuration of FIG. 3 according to the first embodiment of the present invention in more detail, in which FIG. 3A is a diagram showing the overall configuration, and FIG. 3B is an enlarged cross-sectional view of a portion A in FIG. . It is a figure explaining the structure which concerns on the 2nd Embodiment of this invention in detail, (a) is a figure which shows the whole structure, (b) is a side view of (a), (c) is B section of (b). FIG. It is a figure explaining the structure which concerns on the 3rd Embodiment of this invention in detail, (a) is a side view which shows the whole structure, (b) is a top view of (a), (c) is C of (b). It is sectional drawing to which the part was expanded. It is a figure explaining the operation | movement which reads / writes the information recorded on the RF tag attached to the surface of the rotary body with the reader / writer using the conventional loop antenna.

Explanation of symbols

  9a, 9b Loop antenna, 20 antenna, 30 reader / writer, 35 rotating body, 36 central axis, 37 rotating direction, 40 RF tag, 41, 42 magnetic field, 43 synthetic magnetic field, 44 ferrite

Claims (5)

A reader / writer equipped with an antenna for reading and writing information recorded on a moving non-contact information recording medium,
The antenna is composed of at least two loop antennas, and when a combined magnetic field is generated by supplying signals of opposite phases to the respective loop antennas, the combined magnetic field intersects the non-contact information recording medium. A reader / writer characterized in that each loop antenna is arranged.   In order to read and write information recorded on the non-contact information recording medium attached to the peripheral surface of the columnar rotating body that rotates about the central axis, the loop antennas are brought into a non-contact state with the peripheral surface of the rotating body. 2. The reader / writer according to claim 1, wherein the combined magnetic field generated from each of the loop antennas intersects with the non-contact information recording medium.   In order to read and write information recorded on the non-contact information recording medium attached to the surface of a rotating body that rotates about a central axis, the loop antennas are arranged concentrically with respect to the central axis, and 2. The reader / writer according to claim 1, wherein the reader / writer is configured to be opposed to a rotating body so that the combined magnetic field generated from each loop antenna intersects the non-contact information recording medium.   In order to read and write information recorded on the non-contact information recording medium attached to a moving body that moves in a fixed direction or reciprocates, the respective loop antennas are arranged in parallel so as to be opposed to the moving body. 2. The reader / writer according to claim 1, wherein the combined magnetic field generated from each loop antenna intersects with the non-contact information recording medium.   5. The ferrite or spacer is interposed between the non-contact information recording medium and the metal when the rotating body or the moving body is made of metal. The reader / writer described in 1.

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