JP4944538B2 - Reader device, IC tag, IC tag system using them, and communication method of IC tag system - Google Patents

Description

  The present invention relates to an IC tag system, and more particularly to an IC tag system that transmits and receives data using a change in an electric field.

  In recent years, the technology of an IC tag such as an RFID tag has been improved and is being used for various purposes. For example, in the logistics industry, IC tags are attached to cargo and recognized, and the delivery of the cargo is managed, or IC tags are attached to products sold at stores etc. and recognized at the cash register. The use of a system for payment is also being considered.

  However, in the conventional IC tag system, since transmission and reception of data signals between the reader part and the IC tag part are generally performed via radio waves, the IC tag is adjacent to the radio wave absorber. In such a case, there arises a problem that the data signal transmitted from the reader side cannot be received, and the usage range and method of the IC tag system are limited.

  Specifically, the problem with conventional IC tags using wireless radio waves is that if an IC tag is attached to a cargo packaging box that contains radio wave absorbers such as fruits containing a lot of metal or moisture, the data signal is It means that it cannot be recognized or the recognition rate is lowered. In addition, when the data signals are collectively recognized with a large number of cargo boxes stacked, or when the cardboard boxes are damp, there is a problem that the recognition rate is low. Furthermore, there is a problem that it is difficult to recognize a data signal if the contents move while attached to frozen food or the like. In addition, since radio waves are used, there is a problem that the frequency band to be used is limited. As described above, the IC tag system using radio waves in the conventional example has the above-described disadvantages and has a problem in practical use.

  On the other hand, Patent Document 1 below discloses a technique for transmitting and receiving ultrasonic data by using a piezoelectric ultrasonic transducer such as a PVDF film on the reader side and the tag side. As described above, since ultrasonic vibration can be transmitted as data signals through air, water, and solids by using ultrasonic vibration for data transmission and reception, stacked cargo that has been difficult with conventional IC tag systems. Also, it is possible to collectively recognize IC tags attached to radio wave absorbers such as metals and beverages, fruits having a lot of moisture, and the like. In addition, it can be used for cargo recognition of precision electronic devices and electronic devices that may cause damage due to radio wave irradiation.

JP-T-2005-522921

  However, since the propagation distance of ultrasonic vibration is short, there is a problem that it is difficult to perform reliable communication if the distance between the reader side and the IC tag side is long. For example, the ultrasonic vibration of 40 to 125 kHz is attenuated to about 1/100 in 1 m in the air, so it is attached to the cargo as described above and used for recognition. Is difficult.

  On the other hand, although it is conceivable to increase the power (intensity) of the ultrasonic vibration, depending on the value of the power, there is a problem that it affects animal and plant cells. For example, if a freight or product with an IC tag affixed is a perishable food product, the quality may be adversely affected, and the human body may also be adversely affected by surrounding people. A possibility arises.

  Furthermore, since ultrasonic waves have a property of reflecting when irradiated on an object, the ultrasonic wave transmitted to detect the IC tag affects the reader's receiving unit, and performs highly accurate transmission / reception. The problem arises that it becomes difficult.

  Therefore, an object of the present invention is to provide an IC tag system that improves the disadvantages of the above-described conventional example and that is particularly versatile and has high recognition accuracy.

Therefore, a reader device according to one aspect of the present invention is
A voltage signal output means for generating and outputting a voltage signal for reading the IC tag; an IC tag signal receiving means for detecting a response signal returned from the IC tag capable of detecting the voltage signal to the voltage signal; and a voltage Control means for controlling the signal output operation and the response signal reception operation;
It is characterized by having.

  According to the above invention, first, a read signal for the IC tag is output from the reader device as a voltage signal represented by a change in electric field. When the IC tag detects the read signal due to the change in the electric field, a response signal in response thereto is returned. Then, when the reader device receives this response signal, the presence of the object to which the IC tag is attached can be detected.

  Therefore, in the above configuration, since the read signal is output as a voltage signal to the IC tag, the read signal is not affected by the radio wave absorber without using the conventionally used radio wave. Can be output without receiving, and high-accuracy communication with the IC tag can be performed. In addition, since no ultrasonic waves are used, the communication distance can be increased, and adverse effects on animal and plant cells can be suppressed. As a result, damage to the object to which the IC tag is attached can be suppressed, and the influence on the human body can be suppressed, so that a highly versatile IC tag system can be provided.

  The voltage signal output means is formed by a pair of electrodes. At this time, a pair of electrodes is provided in the vicinity of a place where an object to which an IC tag is attached is located. Further, the present invention is characterized in that a pair of electrodes are provided so as to sandwich a portion where an object with an IC tag is located.

  Thereby, the voltage signal output means can be formed with a simple configuration, and the cost of the apparatus can be reduced. Then, by providing a pair of electrodes in the vicinity of the location where the object to which the IC tag is attached is located so as to sandwich the location, the read signal is output so that the IC tag can detect it more accurately. can do.

  In addition, a voltage signal is output by the voltage signal output means, and a shielding means for shielding an electromagnetic wave from the outside is provided, which surrounds a space where an object with an IC tag is located and shields at least electromagnetic waves from the outside. Yes. At this time, the shielding means has a function of shielding the ultrasonic wave from the outside. In addition, the IC tag signal receiving means is arranged inside the shielding means on the side where the object to which the IC tag is attached is located. Furthermore, one of the pair of electrodes described above is formed by the shielding means.

  Thereby, it can suppress that electromagnetic waves and an ultrasonic wave approach from the circumference | surroundings to the space which detects an IC tag, and can transmit / receive a read signal and a response signal with higher precision. At this time, the reader device can be efficiently configured by using the shielding means as one electrode for outputting a read signal.

  In the present invention, the IC tag signal receiving means is particularly preferably a porous piezoelectric film. Thereby, when the IC tag is a porous piezoelectric film, even when a voltage signal or an ultrasonic signal is output as the response signal, the response signal can be received with higher accuracy.

In addition, an IC tag which is another embodiment of the present invention is
Voltage signal detection means for detecting a voltage signal for reading an IC tag output from the reader device, response signal output means for outputting a response signal to the voltage signal, voltage signal detection operation and response signal output operation And a control means for controlling. For example, the voltage signal detection means is a porous piezoelectric film. The response signal output means outputs the response signal as a voltage signal. At this time, the voltage signal detection means and the response signal output means may be constituted by one porous piezoelectric film. .

  Thereby, the change of the electric field by the voltage signal which is the read signal output from the reader device can be detected with higher accuracy by the voltage signal detecting means such as the porous piezoelectric film. And since a voltage signal detection means and a response signal output means can be comprised with one porous piezoelectric film, size reduction and cost reduction of an IC tag can be achieved.

  The present invention also provides an IC tag system including the above-described reader device and IC tag.

Furthermore, the communication method of the IC tag system according to another aspect of the present invention is as follows:
A first step in which the reader device outputs a read signal and the IC tag detects the read signal;
A second step of outputting a response signal according to the read signal detected by the IC tag, and receiving the response signal by the reader device;
A communication method of an IC tag system having
In the first step, the reader device outputs a read signal as a voltage signal, and the IC tag detects the read signal based on the voltage signal.
It is characterized by that.

  The second step is characterized in that the IC tag outputs a response signal as a voltage signal, and the reader device receives the response signal based on the voltage signal.

  Even the invention of the above-described IC tag system and its communication method operates in the same manner as the reader device or the IC tag, so that the object of the present invention described above can be achieved.

  Since the present invention is configured and functions as described above, according to this, since a read signal is output as a voltage signal to the IC tag, a conventionally used radio wave is used for the read signal. Therefore, the read signal can be output without being affected by the radio wave absorber, and high-accuracy communication with the IC tag can be performed. Furthermore, since the ultrasonic wave is not used, the communication distance can be increased, and it is possible to suppress the adverse effect on the animal and plant cells, so that it is possible to suppress the damage to the object to which the IC tag is attached, It has an unprecedented excellent effect that the influence on the human body can be suppressed and the versatility can be improved.

  The IC tag system according to the present invention is characterized in that data is transmitted and received through a voltage signal. Hereinafter, specific configurations and operations will be described with reference to examples.

  A first embodiment of the present invention will be described with reference to FIGS. 1 to 4 are diagrams showing the configuration and characteristics of an IC tag. 5 to 6 are diagrams showing the configuration of an IC tag system including a reader device and an IC tag. FIG. 7 is a diagram illustrating signals used for communication.

[Constitution]
The IC tag system according to the present invention includes an IC tag 20 attached to an object 40 such as cargo, and a reader device 10 that communicates with the IC tag 20. The reader device 10 detects the presence of the IC tag 20. For example, the reader device 10 is installed at a cash register in a supermarket, and the IC tag 20 is attached to and used for a product sold in the supermarket. Hereinafter, each configuration will be described in detail.

<IC tag>
For example, as shown in FIG. 5, the IC tag 20 is a tag attached to a cargo such as a commodity sold in a supermarket or the like, and is formed in a thin plate shape. Specifically, as shown in the top view of FIG. 1A and the side view of FIG. 1B, an IC tag chip serving as a control unit on a thin plate-like base film 21 attached to the object 40. 23 and a porous FEP 23 serving as an antenna. For example, it can be configured with a width of 15 mm, a length of 30 mm and a thickness of 1 to 4 mm.

  Here, the porous FEP 23 will be described in detail with reference to FIG. The porous FEP 23 is a porous piezoelectric film, and the structure thereof includes a polarized foamed FEP 23a sandwiched between vapor deposition electrodes 23b as shown in the cross-sectional view of FIG. ing. The porous FEP 23 is characterized in that the piezoelectric effect is enhanced by space charge polarization. Here, there is a porous PP as a similar material, but the maximum use temperature is that the porous PP is about + 50 ° C., whereas the foamed FEP used in this example is as high as about + 80 ° C. Have In addition, the polyvinylidene fluoride sandwiched between the vapor deposition electrodes by PVDF described in Patent Document 1 is not porous, and thus the present invention is different from the prior art. Incidentally, “FEP” is “tetrafluoroethylene-hexafluoropropylene copolymer”.

As shown in FIG. 2B, the properties of the porous FEP 23 include a conversion constant (d ₃₃ ) from electricity to pressure (vibration), and vice versa, from pressure (vibration) to electricity. The conversion constant (g ₃₃ ) is far superior to PZT and PVDF.

  Further, the porous FEP 23 has a property of sensitively reacting to a change in electric field. This property will be described with reference to FIGS. FIG. 3 is a diagram showing an apparatus for measuring the above-described properties. As shown in FIG. 3, a voltage signal, that is, an electric field E is output from the + electrode 101 connected to the piezo driver, and this is output to the oscilloscope. Thus, measurement is performed to detect the porous FEP 103 connected to the probe 102 as a detection sensor. And the measurement result at that time is shown in FIG. In the measurement result table, the distance from the positive electrode 101 of the porous FEP 103 is shown as the height. Then, it turns out that porous FEP23 can detect the change of an electric field with high precision, and functions as a means to detect a voltage signal.

  As described above, by using the porous FEP 23 as a sensor (antenna) of the IC tag 20, it is possible to accurately detect a voltage signal as a read signal output from the reader device 10 as described later.

  The substrate film 21 on which the porous FEP 23 is placed in the IC tag 20 is, for example, a plastic sheet or a printed board.

  Then, as shown in FIG. 6, the IC tag chip 22 (control means) of the IC tag 20 includes a filter and amplifier circuit 22a, a power supply circuit 22b, an encoding circuit 22c, a control circuit 22d, a memory 22e, an encoding circuit 22f, and a drive. A circuit 22f is provided. Each of these circuits detects a voltage signal that is a read signal output from the reader device 10 as shown by an arrow Y1 in FIG. 6, drives the porous FEP 23, and responds to the read signal, for example, itself. The response signal including the identification information stored in the memory 22e is returned by the porous FEP 23.

  At this time, the porous FEP 23 is vibrated by the piezoelectric effect and transmits ultrasonic waves when a voltage is applied from the drive circuit 22g. That is, the response signal for the reader device 10 is output by ultrasonic waves, and the response signal output means functions. At this time, the porous FEP 23 also generates a voltage signal by the drive control by the drive circuit 22g, and the response signal is also output by the voltage signal. Here, as shown in FIG. 7B, the response signal is a signal representing a binary value of “0, 1” depending on changes in the intensity of the ultrasonic wave or the voltage signal.・ ”Is output.

  Thus, the porous FEP 23 operates to detect a read signal based on the voltage signal from the reader device 10 (voltage signal detection means) and also operates to output a response signal in response thereto (response signal output means). .

  Here, each circuit constituting the above-described IC tag chip 22 functions to output a response signal in response to the received read signal in substantially the same manner as in the conventional IC tag system, and thus detailed description thereof is omitted.

  In the above description, the case where the porous FEP is used as the means for detecting the read signal based on the voltage signal from the reader device 10 has been exemplified. However, an element capable of detecting other voltage signals (voltage signal detection means). ) May be used. In the above, the porous FEP 23 is also used as an element for outputting a response signal by a voltage signal or ultrasonic wave. However, an element for outputting a response signal is another element (response signal output). (Means).

<Reader device>
Next, the reader device 10 will be described. As shown in FIG. 5, the reader device 10 is installed at a place where an object with an IC tag 20 is conveyed, and generates a voltage signal generator 11 (voltage signal output) that generates a voltage signal as a read signal for the IC tag 20. Means), a shield 14 (shielding means) for shielding magnetism / ultrasonic waves surrounding a portion where a voltage signal is transmitted as a reading portion of the IC tag 20, and an IC tag 20 provided on the inner surface side of the shield 14 Sensor 12 (IC tag signal receiving means) that receives a response signal from the control unit 13 and a control circuit 13 (control means) that controls the operation of the reader device 20 itself.

  And as shown in FIG. 5, the voltage signal generator 11 of the reader apparatus 10 is comprised by a pair of electrode. When a voltage is applied between the electrodes based on a drive signal from the drive circuit 13 c of the control circuit 13, a voltage signal due to a change in electric field is output to the space surrounded by the shield 14. Become. At this time, as shown in FIG. 7A, the output voltage signal is a voltage signal representing a binary value of “0, 1” due to a change in the strength of the electric field. For example, “Is there an IC tag? ”And a call end signal are transmitted. As shown in FIG. 5, the object with the IC tag 20 attached to the voltage signal generator 11 is transported and passes, but in the vicinity of the location where the object with the IC tag 20 is located as described above. By providing the voltage signal generator 11 in the IC tag 20, communication with the IC tag 20 can be performed with higher accuracy.

  Here, the shield 14 is formed in a tunnel shape, for example, with copper or aluminum, and is in a state where radio waves and ultrasonic waves from the outside are shielded inside. The tunnel is equipped with a conveyor or the like so that an object with the IC tag 20 is passed through, and the bottom surface is equipped with a pair of electrodes that are the voltage signal generator 11 described above. . Therefore, only the read signal based on the voltage signal output from the voltage signal generator 11 and the response signal based on the ultrasonic wave or voltage signal output from the IC tag 20 exist in the tunnel surrounded by the shield 14. Will be.

  The porous FEP as the sensor 12 has the same configuration as that used for the IC tag 20 described above, and can detect ultrasonic waves and voltage signals. Therefore, as described above, it is possible to detect an ultrasonic wave or a voltage signal as a response signal output from the porous FEP 23 of the IC tag 20 as shown in FIG. 7B, and this detected signal is controlled. Notification is made to the host computer via the circuit 13a.

  Further, as shown in FIG. 6, the control circuit 13 of the reader device 10 includes a control circuit 13a connected to the host computer, an encoding circuit 13b, a drive circuit 13c, and a power supply circuit 13f. As described above, the voltage signal generator 11 outputs a voltage signal as a read signal by the operation. Further, the control circuit 13 of the reader device 10 includes a filter and amplifier circuit 13d and an encoding circuit 13e, and detects an ultrasonic signal and a voltage signal transmitted from the IC tag 20 by the porous FEP 12, This is notified to the host computer via the control circuit 13a.

[Operation]
Next, the operation of the above-described IC tag system will be described. Note that a supermarket cash register is assumed as a usage scene, and the above-described reader device 10 is installed in the cash register. Each product has an IC tag 20 attached thereto, and the shopper passes the shopping basket containing the product through the reader device 10.

  First, the reader device 10 generates a voltage signal representing a read signal for reading the IC tag 20 by the drive circuit 13c (see arrow Y1 in FIG. 6), and outputs it in the shield 14. Here, when the product put in the shopping basket is conveyed, a read signal is detected by the porous FEP 23 of the IC tag 20 (first step). At this time, since radio waves and ultrasonic waves from the outside are shielded in the shield 14, the porous FEP 23 of the IC tag 20 can react only to the read signal from the reader device 10 with higher accuracy. Since the read signal output from the reader device 10 is a voltage signal, it propagates over a long distance regardless of the presence or absence of the radio wave absorber and is detected without omission by each IC tag 20 attached to a plurality of products. Is done.

  In the IC tag 20, the unique ID stored in the memory 22e is transmitted to the drive circuit 22g in accordance with the detected read signal to drive the porous FEP 23, and the ultrasonic vibration or the response signal is generated. A voltage signal is generated and output into the shield 14 (see arrow Y2 in FIG. 6). Then, since radio waves and ultrasonic waves from the outside are shielded in the shield 14, the response signal is detected with high accuracy by the sensor 12 of the reader device 10 attached to the inner wall of the shield 14. As a result, the reader device 10 can collectively recognize the existing IC tags 20 (second step). Thereafter, the response signal received by the reader device 10 is notified to the host computer via the control circuit 13a and is processed for accounting.

  As described above, since the IC tag system according to the present embodiment first uses a voltage signal as a read signal output from the reader device 10, it can be used in any scene regardless of the presence of a radio wave absorber. it can. In other words, the present invention can be applied to cargoes such as devices and electronic devices sensitive to radio waves, and can also be used with IC tags attached to commodities such as foods. In addition, since no ultrasonic waves are used, the influence on the human body can be suppressed and the propagation distance can be extended. As a result, it is possible to collectively recognize objects to which the IC tag 20 is attached. For example, the IC tag 20 can be attached to a freight in the logistics industry, the distribution industry, etc., or attached to a product in a supermarket. It is possible to improve the efficiency of payment management at the cash register and cash register.

  Next, a second embodiment of the present invention will be described with reference to FIG. The IC tag 120 in this embodiment has almost the same configuration as the IC tag 20 described above. However, as shown in FIG. 8, instead of the base film, the IC tag 120 functions as an active type. A thin film battery 121 is provided. The film battery 121 feeds power to the IC tag chip 122, thereby being used as a driving power source at the time of reading signal detection processing or as a driving power source at the time of response signal transmission.

  As described above, by configuring the porous FEP 123 on the film battery 121, the sensitivity of the read signal by the porous FEP 23 increases, that is, the electromotive force when the read signal that is a voltage signal is detected. It has been confirmed by experiments that it becomes larger.

  Next, a third embodiment of the present invention will be described with reference to FIG. The reader device 110 in the present embodiment has a configuration substantially similar to that of the reader device 10 described above, but the configuration of the voltage signal generator 11 is different. This different configuration will be described in detail.

  As shown in FIG. 9, the reader device 110 in the present embodiment first includes a tunnel-shaped shield 114, a sensor 112 attached to the inner wall thereof, and a control circuit 113, as in the above-described embodiment. . Further, the voltage signal generator 111 includes a voltage variable electrode 111a on the bottom surface of the shield 114 on the + electrode side and a ground side electrode 111b made of the shield 114 itself. As a result, the position through which the object with the IC tag 20 passes is sandwiched between the electrodes 111a and 111b, and the read signal is directed from the bottom to the shield 114, that is, from below to above. A voltage signal (change in electric field) can be generated. The + side electrode and the ground side electrode may be interchanged.

  As described above, since the pair of electrodes are provided so as to sandwich the portion through which the IC tag 20 passes, a read signal can be output so that the IC tag 20 can detect it with higher accuracy. As a result, the IC tags 20 can be collectively recognized with high accuracy.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. The reader device 210 in this embodiment outputs a reading signal by ultrasonic vibration to a case 210a holding the whole device and a cargo 240 attached to the case 210a and attached with an IC tag 220 to be read. Piezoelectric actuator 211 (reading signal output means), a sensor 212 (response signal receiving means) that receives a response signal from the IC tag 220 to the read signal, and a shield 214 (shielding) that surrounds the cargo 240 and shields radio waves and ultrasonic waves. Means).

  The piezoelectric actuator 211 is, for example, a Langevin type piezoelectric ceramic vibrator, and is in contact with the cargo 240 via a plate 211a. The piezoelectric actuator 211 outputs a reading signal as shown in FIG. 7A by ultrasonic vibration, and outputs the ultrasonic vibration directly to the cargo 240. At this time, since the cargoes 240 in this embodiment are all in contact with each other, the reading signals by ultrasonic waves are more reliably transmitted to all the cargos 240. Then, the read signal is also transmitted to the IC tag 220 attached to each cargo 240.

  The IC tag 220 attached to the cargo 240 is provided with the porous FEP described above as a sensor. By this porous FEP, a read signal that is ultrasonic vibration is detected and converted into an electrical signal. The Further, the IC tag 220 is provided with an IC tag chip that performs a detection process of a read signal and an output process of a response signal in response to the same as described above. In this IC tag chip, a response signal to the detected read signal is generated, and a voltage signal is applied to the porous FEP used as a sensor to output the response signal. Thereby, the porous FEP on the IC tag 220 can output a response signal by ultrasonic vibration or a voltage signal.

  The response signal output from the IC unit 220 is received by the sensor 212 which is a part of the reader device 210 provided in the shield 214. This sensor 212 is composed of porous FEP, and can detect a response signal by an ultrasonic wave or a voltage signal as described above. Thereby, the IC tag 220 can be detected.

  Here, the IC tag 220 described above has substantially the same configuration as that shown in FIG. 1, but uses a shear wave filter instead of the base film 21, and a porous FEP, an IC tag chip, and the like. May be configured. As a result, the shear wave filter is positioned between the object to which the IC tag 220 is attached and the porous FEP. Note that the transverse wave filter may be, for example, a liquid such as water, specifically, a plastic bag filled with water or a gel-like body.

  Thereby, even when the IC tag is attached to an object, it is possible to remove the transverse wave mixed in other signals that are transmitted through the object, and to perform detection with higher accuracy.

  According to the IC tag system of the present invention, it is possible to collectively recognize product data signals of stacked cargo and shopping carts, which can be used in the logistics industry, distribution industry, supermarket cash register, etc. With the availability of

2 is a diagram illustrating a configuration of an IC tag in Embodiment 1. FIG. It is a figure which shows the structure and characteristic of porous FEP used for an IC tag. It is a figure which shows the mode of experiment which investigates the characteristic of porous FEP. It is a figure which shows the characteristic of porous FEP. It is a figure which shows the structure of the reader apparatus in Example 1. FIG. It is a block diagram which shows the structure of the IC tag system in Example 1. FIG. It is a figure which shows the mode of the signal transmitted / received by an IC tag system. 6 is a diagram illustrating a configuration of an IC tag in Embodiment 2. FIG. It is a figure which shows the structure of the reader apparatus in Example 3. FIG. It is a figure which shows the structure of the IC tag system in Example 4. FIG.

Explanation of symbols

10 Reader Device 11 Voltage Signal Generator 12 Sensor (Porous FEP)
13 Control Circuit 14 Shield 20 IC Tag 21 Base Film 22 IC Tag Chip 23 Porous FEP
23a Foamed FEP
23b Deposition electrode 40 Object

Claims (6)

A voltage signal output means for generating and outputting a voltage signal for reading the IC tag; an IC tag signal receiving means for detecting a response signal returned from the IC tag capable of detecting the voltage signal to the voltage signal; e Bei control means for controlling the receiving operation of the output operation and the response signal of the voltage signal, and
The voltage signal output means is formed by a pair of electrodes ,
A voltage signal is output by the voltage signal output means and a space for shielding an electromagnetic wave from the outside is provided, surrounding a space where an object to which the IC tag is attached passes.
The IC tag signal receiving means is disposed inside the shielding means on the side where the object to which the IC tag is attached passes,
One of the pair of electrodes is formed by the shielding means, and the pair of electrodes is provided so as to sandwich a portion through which an object to which the IC tag is attached passes.
A reader device. It said shielding means has a function to shield the ultrasonic waves from an external reader device according to claim 1, wherein a. The IC tag signal receiver means is a porous piezoelectric film, the reader device according to claim 1 or 2, wherein the. A first step in which the reader device outputs a read signal and the IC tag detects the read signal;
A second step of outputting a response signal according to the read signal detected by the IC tag, and receiving the response signal by the reader device;
A communication method of an IC tag system having
In the first step, the reader device outputs the read signal as a voltage signal generated by a pair of electrodes provided so as to sandwich a portion through which an object to which the IC tag is attached passes. One of the electrodes is formed by shielding means that surrounds a space where the object to which the voltage tag is output and the IC tag is attached passes, and at least shields electromagnetic waves from the outside. The IC tag detects the signal ,
In the second step, the IC tag outputs the response signal as a voltage signal, and the response signal based on the voltage signal is inside the shielding means on the side where the object to which the IC tag is attached passes. The reader device receives the IC tag signal receiving means arranged in the
An IC tag system communication method characterized by the above. In the first step, the IC tag detects the read signal output as a voltage signal from the reader device with a porous piezoelectric film,
The communication method of an IC tag system according to claim 4 . In the second step, the reader device receives the response signal output as a voltage signal from the IC tag by a porous piezoelectric film.
6. A communication method for an IC tag system according to claim 4 or 5, wherein:

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