JP2007060416A - Contactless ic tag, reader device, information writing system, and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly improve characteristics of communication with a contactless IC tag. <P>SOLUTION: The problem to be solved can be solved by a reader device 100 which is equipped with a resonance circuit 102 capable of altering electromagnetic characteristics during access to the contactless IC tag 200, and reads resonance circuit setting information previously registered in the contactless IC tag 200 and used to set the resonance circuit 102 to alter the electromagnetic characteristics of the resonance circuit 102 based upon the resonance circuit setting information read out of the contactless IC tag 200. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a contactless IC tag, a reader device, an information writing system, and a reader / writer control method that improve communication with a contactless IC tag.

  A small non-contact IC tag is used for identification of an object. The shape of the non-contact IC tag includes a label type, a card type, a coin type, a stick type and the like, and can be selected according to the application. The non-contact IC tag has a size of several millimeters to several centimeters, and can communicate with a reader / writer device (reading / writing device) for the IC tag by radio waves or electromagnetic waves.

  Each of the non-contact IC tag and the reader / writer device is provided with a resonance circuit including an antenna having an inductive component and a capacitor having a capacitive component. When storing information in a non-contact IC tag or reading information stored in a non-contact IC tag, the antenna of the resonance circuit of the reader / writer device is electromagnetically coupled to the antenna of the resonance circuit of the non-contact IC tag. The information is transmitted and written or read while supplying power to the IC tag by radio waves from the reader / writer device side by applying a non-contact power transmission technique close to the extent of being coupled. As a result, the non-contact IC tag can be used semi-permanently without incorporating a battery. The communication distance between the non-contact IC tag and the reader / writer device ranges from several mm to several meters and can be used properly according to the application.

  In Patent Document 1, in such a system using a non-contact IC tag, the resonance circuit capacitor built in the reader / writer device is a variable capacitor, and the capacitance of the variable capacitor is automatically changed in order to resonate. A technique for sequentially adjusting the resonance frequency of a circuit is disclosed. In this way, the response signal from the non-contact IC tag is detected while adjusting the resonance frequency of the resonance circuit, and the response signal with the largest peak width and the largest number of peaks is selected from the detected response signals. Then, communication is performed by setting the reader / writer device to a resonance frequency corresponding to the optimum response signal.

JP 2000-172792 A

  In the above prior art, the optimum response signal is selected from the response signals of the non-contact IC tag while adjusting the resonance frequency of the resonance circuit. At this time, in order to select the optimum response signal, it is necessary to change the resonance circuit of the reader / writer device in advance over the entire range in which the resonance frequency can be adjusted. Therefore, there is a problem that it takes a long time to set the resonance circuit of the reader / writer device to the optimum condition for the non-contact IC tag to be communicated.

  Further, it is necessary to provide a detection circuit for selecting a response signal having the largest peak width and the largest number of peaks from the response signals of the non-contact IC tag, and the internal circuit of the reader / writer device becomes complicated.

  In view of the above-described problems of the prior art, the present invention provides a non-contact IC tag, a reader device, an information writing system, and a reader that have improved communication with the non-contact IC tag in order to solve at least one of the problems of the prior art. It is an object of the present invention to provide a method for controlling a writer device.

  The present invention is a reader device that can access a non-contact IC tag by electromagnetic means, and includes a resonance circuit that can change an electromagnetic characteristic when accessing the non-contact IC tag. The resonance circuit is read based on the resonance circuit setting information read from the non-contact IC tag to be accessed by reading the resonance circuit setting information used for setting the resonance circuit registered in advance in the contact IC tag. It is characterized by comprising means for changing the electromagnetic characteristics of Of course, the present invention may include a reader configuration that can read information from a non-contact IC tag by electromagnetic means, but further includes a reader writer configuration that can write information to the non-contact IC tag by electromagnetic means. It may be a device.

  An access method for accessing a non-contact IC tag by electromagnetic means by using this reader device, and a resonance circuit setting used for setting a resonance circuit registered in advance in the non-contact IC tag to be accessed A first step of reading information; and a second step of changing electromagnetic characteristics of the resonance circuit included in the reader device based on the resonance circuit setting information read in the first step. Can be realized.

  Here, when the resonance circuit includes a variable resistance unit having a variable resistance value and a variable capacitance unit having a variable capacitance value, the resonance circuit read from the contactless IC tag to be accessed It is preferable that the electromagnetic characteristic of the resonance circuit is set by setting at least one of a resistance value of the variable resistor unit and a capacitance value of the variable capacitor unit based on setting information.

  Further, when the resonance circuit includes a plurality of antennas having different characteristics, at least one of the plurality of antennas based on resonance circuit setting information read from the non-contact IC tag to be accessed. It is preferable to select one and set the electromagnetic characteristics of the resonant circuit.

  The resonance circuit setting information is determined based on the electromagnetic characteristics of the resonance circuit included in the non-contact IC tag, and is registered in a memory built in the non-contact IC tag. At this time, a parameter for controlling the electromagnetic characteristics of the resonance circuit and a parameter set in advance corresponding to the resonance circuit setting information is searched, and the electromagnetic of the resonance circuit is searched using the parameter. It is preferable to change the characteristics.

  The present invention also provides a non-contact IC tag having a built-in memory for holding electronic information and capable of accessing information held in the built-in memory from a reader device by electromagnetic means. In the reader / writer device, resonance circuit setting information used for setting electromagnetic characteristics of a resonance circuit used for access is stored. Here, the resonance circuit setting information is determined based on the electromagnetic characteristics of the resonance circuit included in the non-contact IC tag, and is registered in the built-in memory.

  Here, when the resonance circuit setting information is accessed, it is preferable to transmit at higher output than during normal data transmission.

  The present invention also provides an information writing system for a non-contact IC tag that can access information held in an internal memory from the outside by electromagnetic means, and includes a resonance circuit used for accessing the internal memory. Resonant circuit setting information used for setting electromagnetic characteristics is written.

  More specifically, an IC tag inspection device that measures the electromagnetic characteristics of the resonance circuit included in the non-contact IC tag is provided, and the electromagnetic of the resonance circuit included in the non-contact IC tag measured by the IC tag inspection device. Resonant circuit setting information is determined based on typical characteristics.

  By using this information writing system, a method of writing information to a non-contact IC tag accessible by electromagnetic means, the electromagnetic circuit of a resonance circuit used for access to a built-in memory of the non-contact IC tag It is possible to realize a writing method characterized by writing the resonance circuit setting information used for setting various characteristics.

  In this way, by registering the resonance circuit setting information in the non-contact IC tag in advance, the resonance circuit included in the reader device can be accessed based on the resonance circuit setting information registered in the non-contact IC tag itself. It is possible to provide a setting environment suitable for a non-contact IC tag. That is, once the information can be read from the non-contact IC tag, the characteristics of the resonance circuit of the reader / writer device based on the resonance circuit setting information registered in the memory of the non-contact IC tag itself to be accessed. (For example, resonance frequency, Q value, etc.) can be adjusted to an optimal setting. At this time, it is not necessary to investigate whether or not an optimum response signal can be obtained over the entire adjustable range of the resonance circuit, and the time required for setting the resonance circuit of the writer device to the optimum condition is shortened. Can do.

  Further, it is not necessary to provide a detection circuit for selecting the optimum response signal from the response signals of the non-contact IC tag, and the configuration of the writer device is simplified.

  According to the present invention, communication characteristics with a non-contact IC tag can be improved by a simpler circuit than before. In addition, it is possible to shorten the time until the resonance circuit of the reader / writer device is set to the optimum condition for the non-contact IC tag to be communicated.

<System configuration>
The reader / writer device 100 according to the embodiment of the present invention includes an RF resonance circuit 102 and a peripheral circuit 104 as shown in FIG. The reader / writer device 100 exchanges information by electromagnetically coupling with an external non-contact IC tag 200.

  The RF resonance circuit 102 includes a plurality of antennas 10-1 to 10-m (m is a natural number of 2 or more), an antenna switching unit 12, a variable resistor 14, a resistance adjusting unit 16, and a plurality of capacitors 18-1 to 18-n ( n is a natural number of 2 or more) and the capacitor switching unit 20. The peripheral circuit 104 includes an encoding circuit 22, a modulation circuit 24, a demodulation circuit 26, a decoding circuit 28, and a control unit 30. The RF resonance circuit 102 is connected to the modulation circuit 24 and the demodulation circuit 26 of the peripheral circuit 104, and is electromagnetically coupled to the contactless IC tag 200 to be accessed to realize information writing and reading processing. Further, the antenna switching unit 12, the resistance adjusting unit 16, and the capacitor switching unit 20 of the RF resonance circuit 102 are respectively controlled by control signals from the control unit 30 included in the peripheral circuit 104.

  The antennas 10-1 to 10-m have different antenna characteristics. The antennas 10-1 to 10-m bear an inductive component of the resonance circuit in the RF resonance circuit 102. The antennas 10-1 to 10-m have different antenna characteristics such as frequency characteristics, power characteristics, and directivities by making the sizes or shapes different from each other. For example, a large size antenna can be used when transmission output is important, and a small size antenna can be used when reception sensitivity is important. The antenna switching unit 12 receives the antenna switching signal S1 from the control unit 30, and selectively switches the switch according to the antenna switching signal S1, thereby switching any one of the antennas 10-1 to 10-m to a non-contact IC. It is selected as an antenna used for communication with the tag 200.

  The variable resistor 14 is used to adjust the Q value of the resonance circuit in the RF resonance circuit 102. The resistance value of the variable resistor 14 is adjusted by the resistance adjusting unit 16. The resistance adjustment unit 16 receives the resistance value setting signal S2 from the peripheral circuit 104, and changes the resistance value of the variable resistor 14 to a value corresponding to the resistance value setting signal S2.

  Capacitors 18-1 to 18-n have different electric capacities. The capacitors 18-1 to 18-n are used to configure a resonance circuit with any one of the antennas 10-1 to 10-m selected by the antenna switching unit 12 and the variable resistor 14. The capacitor switching unit 20 receives the capacitor switching signal S3 from the control unit 30, and selectively switches one of the capacitors 18-1 to 18-n in accordance with the capacitor switching signal S3 to thereby switch any one of the capacitors 18-1 to 18-n. It is selected as a capacitor constituting a resonance circuit used for communication with the tag 200.

  The antenna selected based on the antenna switching signal S1 and the variable resistor 14 form a series circuit, and both ends thereof are configured to be connected to the modulation circuit 24 and the demodulation circuit 26 included in the peripheral circuit 104. Further, the capacitor selected based on the capacitor switching signal S3 is configured to be connected in parallel to the antenna selected based on the antenna switching signal S1. In this way, an RF resonance circuit is configured.

  The encoding circuit 22 is a circuit that encodes data to be stored in the memory of the contactless IC tag 200. The encoding circuit 22 receives data from the control unit 30, encodes the data in a predetermined format, and outputs the encoded data to the modulation circuit 24. The modulation circuit 24 is a circuit that modulates a carrier wave with input data and outputs the modulated carrier wave. The modulation circuit 24 receives the data encoded by the encoding circuit 22, modulates the encoded data by a predetermined modulation method, and supplies the modulated data to the resonance circuit of the RF resonance circuit 102.

  The demodulation circuit 26 is a circuit that demodulates information read from the non-contact IC tag 200 via the RF resonance circuit 102. The demodulation circuit 26 receives the modulation signal received by the RF resonance circuit 102, demodulates the modulation signal by a predetermined demodulation method, and outputs it to the decoding circuit 28. The decoding circuit 28 is a circuit that decodes the data demodulated by the demodulation circuit 26. The decoding circuit 28 receives the demodulated signal from the demodulation circuit 26, decodes the signal as data of a predetermined format, and passes it to the control unit 30. Since the encoding circuit 22, the modulation circuit 24, the demodulation circuit 26, and the decoding circuit 28 can be configured by applying existing technology, detailed description thereof is omitted.

  The control unit 30 includes a CPU, an internal memory, an input / output interface, and the like, and controls the antenna switching unit 12, the resistance adjustment unit 16, the capacitor switching unit 20, and the peripheral circuit 104 of the RF resonance circuit 102 in an integrated manner. The control unit 30 receives data for writing to the non-contact IC tag 200 from an external device (not shown), and transmits the data to the encoding circuit 22 to perform information writing processing on the non-contact IC tag 200. Execute. Also, it receives the data output from the decoding circuit 28 and outputs it to an external device (not shown). When resonance circuit setting information is stored in advance in the non-contact IC tag 200, the resonance circuit setting information is acquired via the RF resonance circuit 102, the demodulation circuit 26, and the decoding circuit 28, and the resonance circuit setting is obtained. The setting of the RF resonance circuit 102 is adjusted by controlling the antenna switching unit 12, the resistance adjusting unit 16, and the capacitor switching unit 20 based on the information. These processes will be described later.

  The non-contact IC tag 200 has a circuit configuration similar to that of a conventional non-contact IC tag. The non-contact IC tag 200 includes an RF resonance circuit having a CPU, a semiconductor memory, an antenna having a dielectric component, and a capacitor having a capacitance component. The RF resonance circuit of the non-contact IC tag 200 is electromagnetically coupled to the RF resonance circuit 102 of the reader / writer device 100 to realize communication using radio waves. Information newly transmitted from the reader / writer device 100 via the RF resonance circuit of the non-contact IC tag 200 is stored and held in the semiconductor memory. Information already stored in the semiconductor memory is read by the reader / writer 100 and used for various processes. The semiconductor memory can store resonance circuit setting information for setting the RF resonance circuit 102 of the reader / writer device 100. The reader / writer device 100 according to the present embodiment can access a non-contact IC tag 200 having antennas of various shapes or sizes.

<Writing process of resonance circuit setting information to IC tag>
As shown in the conceptual diagram of FIG. 2, the control circuit 300, the IC tag inspection device 302, and the non-contact IC tag 200 are used for the writing process of the resonance circuit setting information to the non-contact IC tag 200 in the present embodiment. Done. The IC tag inspection device 302 includes an RF resonance circuit and an oscillator capable of changing the oscillation frequency. When the IC tag inspection device 302 is electromagnetically coupled to the non-contact IC tag 200 to be inspected, the resonance frequency of the non-contact IC tag 200 is minimized. It has a configuration capable of measuring antenna characteristics such as operating magnetic field and Q value. The IC tag inspection device 302 also functions as a writer device that writes information to the non-contact IC tag 200.

  FIG. 3 shows a flowchart of processing for writing resonance circuit setting information to the non-contact IC tag 200. It is preferable that the writing process of the resonance circuit setting information to the IC tag is performed at the initial inspection before the non-contact IC tag 200 is attached to another device or the like. The process of writing the resonance circuit setting information to the non-contact IC tag 200 is performed by executing a program stored in the computer 300 and controlling the IC tag inspection device 302.

  In step S10, initial setting of processing is performed. The IC tag inspection device 302 and the non-contact IC tag 200 to be inspected are disposed in an electromagnetically coupled state.

  In step S <b> 12, the characteristics of the non-contact IC tag 200 are measured by the IC tag inspection device 302. In response to a control signal from the computer 300, the IC tag inspection device 302 measures the characteristics of the non-contact IC tag 200 by scanning the oscillation frequency. The measurement result is transmitted to the computer 300. In the present embodiment, the resonance frequency, the minimum operating magnetic field, and the Q value of the non-contact IC tag 200 are measured.

  In step S14, resonance circuit setting information stored in the non-contact IC tag 200 is obtained based on the characteristics of the non-contact IC tag 200 measured in step S12. When the computer 300 accesses the non-contact IC tag 200 based on the characteristics (resonance frequency, minimum operating magnetic field and Q value) of the non-contact IC tag 200 measured by the IC tag inspection apparatus 302 in step S12, the reader / writer Resonance circuit setting information for determining an optimum condition for setting the RF resonance circuit 102 of the apparatus 100 is determined.

  That is, the parameter values expected as the characteristics of the non-contact IC tag 200 or a combination thereof and the setting identifier are associated with each other and stored in advance in a memory attached to the computer 300 as an initial setting database. By referring to the database, the setting identifier is extracted as the resonance circuit setting information based on the value of each parameter indicating the characteristic of the non-contact IC tag 200 measured in step S12. The setting identifier is an identifier for setting the RF resonance circuit 102 of the reader / writer device 100 to a configuration suitable for the characteristics of the non-contact IC tag 200 when accessing the non-contact IC tag 200.

  For example, when the resonance frequency, the minimum operating magnetic field, and the Q value are obtained as the characteristics of the non-contact IC tag 200, as shown in FIG. 5, depending on the combination of the resonance frequency range, the minimum operating magnetic field range, and the Q value range. The setting identifier is registered in advance in the initial setting database for each minimum setting condition of the RF resonance circuit 102 of the reader / writer device 100 determined in accordance with the setting identifier based on the characteristics of the non-contact IC tag 200 measured in step S12. To extract.

  At this time, the resonance circuit setting information may be determined in consideration of the use environment of the non-contact IC tag 200 in addition to the value of each parameter expected as the characteristic of the non-contact IC tag 200. The usage environment of the non-contact IC tag 200 is a surrounding environment that affects access between the non-contact IC tag 200 and the reader / writer device 100 in a device to which the non-contact IC tag 200 is actually attached. It is represented by parameters such as the model of the device to which the contact IC tag 200 is attached, the distance between the non-contact IC tag 200 and the reader / writer device 100 at the time of access, the distance between the attachment position of the non-contact IC tag 200 and the surrounding metal object. The

  That is, the setting identifier is stored in the computer 300 as an initial setting database in association with a combination of each parameter value expected as a characteristic of the non-contact IC tag 200 and each parameter value indicating the usage environment of the non-contact IC tag 200. Store in advance in the attached memory. When obtaining the resonance circuit setting information, the parameter representing the actual use environment of the non-contact IC tag 200 is acquired in advance from the user, and the non-contact IC tag 200 measured in step S12 by referring to the initial setting database. The setting identifier associated with the combination of the value of each parameter indicating the characteristic and the value of each parameter indicating the use environment of the non-contact IC tag 200 is extracted as resonance circuit setting information.

  In step S16, it is determined whether or not the non-contact IC tag 200 is defective. If the computer 300 can extract the resonance circuit setting information from the initial setting database based on the parameter values indicating the characteristics of the non-contact IC tag 200 measured in step S12 in step S14, the non-contact IC tag 200 is extracted. If the resonance circuit setting information cannot be extracted from the initial setting database, the non-contact IC tag 200 is assumed to be defective, and the process proceeds to step S20.

  In step S18, the resonance circuit setting information is stored in the memory of the non-contact IC tag 200. The computer 300 stores the setting identifier extracted in step S16 in the memory of the non-contact IC tag 200 as resonance circuit setting information using the IC tag inspection device 302 that also serves as a writer device. Accordingly, the non-contact IC tag 200 is in a state where resonance circuit setting information for setting at least the RF resonance circuit 102 of the reader / writer device 100 to a configuration suitable for the characteristics of the non-contact IC tag 200 is stored in the memory. .

  On the other hand, in step S20, the non-contact IC tag 200 is discarded. If the resonance circuit setting information cannot be extracted from the initial setting database, the non-contact IC tag 200 is discarded as being defective.

  As described above, the resonance circuit setting information indicating the setting conditions of the RF resonance circuit 102 of the reader / writer device 100 can be stored in the internal memory of the good non-contact IC tag 200 and then mounted on the device or the like.

<Reading information from IC tag>
The process of reading information from the IC tag in this embodiment is performed using the reader / writer device 100. FIG. 4 shows a flowchart of information reading processing from the IC tag. It is assumed that the RF resonance circuit 102 of the reader / writer device 100 is set to a predetermined initial state before starting the process of reading information from the IC tag.

  In step S <b> 30, access to the non-contact IC tag 200 is attempted using the reader / writer device 100. The control unit 30 outputs a control signal to the antenna switching unit 12, the resistance adjustment unit 16, and the capacitor switching unit 20 in the RF resonance circuit 102 of the reader / writer device 100, and any one of the antennas 10-1 to 10-m. One of the capacitors 18-1 to 18-n and one of the capacitors 18-1 to 18-n are selected, the variable resistor 14 is set to a predetermined resistance value, and information is read from the memory of the non-contact IC tag 200. For example, the antenna 10-1 and the capacitor 18-1 are selected, the variable resistor 14 is set to the lowest value in the adjustable range, and information is read from the memory of the non-contact IC tag 200.

  If reading of information from the memory of the non-contact IC tag 200 is successful, the process proceeds to step S42. If information cannot be read from the memory of the non-contact IC tag 200, the process proceeds to step S32.

  In step S32, the resistance value of the variable resistor 14 and the capacitance value of the capacitor are changed, and the resonance frequency and Q value of the RF resonance circuit 102 are adjusted. The control unit 30 changes the resistance value setting signal S2 output to the resistance adjustment unit 16 and changes the resistance value of the variable resistor 14 for each predetermined width. In addition, the control unit 30 changes the capacitor switching signal S3 output to the capacitor switching unit 20 so that the capacitors 18-1 to 18-n are sequentially selected. That is, each time the processing is shifted to step S32, the combination of the resistance value of the variable resistor 14 and the capacitance values of the capacitors 18-1 to 18-n is sequentially changed.

  In step S34, access to the non-contact IC tag 200 is attempted using the reader / writer device 100. Attempts to read information from the memory of the non-contact IC tag 200 in the characteristics of the RF resonance circuit 102 determined by the resistance value and the capacitance value set in step S32. If the information has been successfully read from the memory of the non-contact IC tag 200, the process proceeds to step S42. If the information has not been read from the memory of the non-contact IC tag 200, the process proceeds to step S36.

  In step S36, it is determined whether or not all combinations of the variable range step of the variable resistor 14 and the capacitors 18-1 to 18-n have been tried for the antenna currently selected in steps S32 and S34. The When all the combinations of the variable range step of the variable resistor 14 and the capacitors 18-1 to 18-n have been tried, the control unit 30 shifts the process to step S38 and sets the variable range of the variable resistor 14 to the variable range. If all combinations of the step and the capacitors 18-1 to 18-n have not been tried, the process returns to step S32.

  In step S38, it is determined whether or not reading of information from the memory of the non-contact IC tag 200 has been attempted for all of the antennas 10-1 to 10-m. The control unit 30 terminates the processing when information reading from the memory of the non-contact IC tag 200 is attempted for all the antennas 10-1 to 10-m, and the antennas 10-1 to 10-m If reading of information from the memory of the non-contact IC tag 200 is not attempted, the process proceeds to step S40.

  In step S40, an antenna that has not been selected among the antennas 10-1 to 10-m is selected. The control unit 30 changes the antenna switching signal S <b> 1 output to the antenna switching unit 12 and selects an antenna that has not been selected as a component of the RF resonance circuit 102. For example, the antenna 10-1 to the antenna 10-m are selected in order each time the process proceeds to step S40. In addition, the control unit 30 returns the resistance value setting signal S2 output to the resistance adjustment unit 16 and the capacitor switching signal S3 output to the capacitor switching unit 20 to initial values, and shifts the processing to step S32.

  As described above, in steps S30 to S40, information is tried to be read from the memory of the non-contact IC tag 200 while changing the combination of the antenna, the resistance value, and the capacitance value in order, If the information can be read from the memory, a process of moving the process to step S42 is performed.

  In step S42, the resonance circuit setting information is read from the memory of the non-contact IC tag 200. The control unit 30 reads the resonance circuit setting information stored in the memory of the non-contact IC tag 200 in the current setting state of the RF resonance circuit 102. The resonance circuit setting information is demodulated and decoded via the demodulation circuit 26 and the decoding circuit 28 and input to the control unit 30.

  In step S44, the RF resonance circuit 102 of the reader / writer device 100 is set based on the resonance circuit setting information. As shown in FIG. 5, the memory attached to the control unit 30 includes an antenna, a resistance value, and a capacitance value that are optimal for accessing the non-contact IC tag 200 in association with the resonance circuit setting information (here, the setting identifier). The combination parameter is registered in advance as a resonance circuit setting database. The control unit 30 extracts the combination parameters of the antenna, the resistance value, and the capacitance value that are associated with the resonance circuit setting information read from the contactless IC tag 200 in step S42, and the RF resonance circuit 102 determines the combination of these parameters. The antenna switching signal S1, the resistance value setting signal S2, and the capacitor switching signal S3 are output to the antenna switching unit 12, the resistance adjustment unit 16, and the capacitor switching unit 20, respectively.

  In step S46, access to the normal non-contact IC tag 200 is performed. The control unit 30 reads information from the non-contact IC tag 200 and writes information to the non-contact IC tag 200 based on the configuration of the RF resonance circuit 102 set based on the resonance circuit setting information in step S44. .

  As described above, according to the present embodiment, the optimum setting of the RF resonance circuit 102 according to the resonance circuit setting information registered in the non-contact IC tag 200 in advance in the writing process of the resonance circuit setting information to the IC tag. The contactless IC tag 200 can be accessed in the environment.

  Once the information can be read from the non-contact IC tag 200, the RF of the reader / writer device 100 is based on the resonance circuit setting information registered in the memory of the non-contact IC tag 200 itself to be accessed. The resonance frequency, Q value, etc. of the resonance circuit 102 can be adjusted to an optimum setting. That is, it is not necessary to adjust the RF resonance circuit 102 over the entire adjustable range of the RF resonance circuit 102, and the time required for setting the RF resonance circuit 102 of the reader / writer device 100 to the optimum condition is shortened. be able to.

  Further, it is not necessary to provide a detection circuit for selecting the optimum response signal from the response signals of the non-contact IC tag, and the configuration of the reader / writer device 100 can be simplified.

  In this embodiment, all of the antenna, the resistance component, and the capacitance component in the resonance circuit of the reader / writer device can be adjusted. However, any one or more of these can be adjusted according to a necessary adjustment range. That's fine.

  In the present embodiment, the reader / writer device changes the parameters for changing the electromagnetic characteristics of the resonance circuit in a predetermined order until the resonance circuit setting information is acquired. The setting of the resonance circuit used when accessing another non-contact IC tag may be stored, and the setting of this resonance circuit may be used. In this way, when the same type of contactless IC tag is used, the resonance circuit setting information can be acquired immediately.

  The non-contact IC tag may output the resonance circuit setting information at a higher output when reading the resonance circuit setting information than when reading normal information having a larger data amount than the resonance circuit setting information. In this way, it is possible to obtain the resonance circuit setting information even when the RF resonance circuit 102 of the reader / writer device 100 is not optimally set.

  In this embodiment, the setting identifier associated with the combination of the optimum antenna, resistance value, and capacitance value is used as the resonance circuit setting information. However, the optimum antenna, resistance value, and capacitance value itself are used as the resonance circuit setting information. May be stored in the memory of the non-contact IC tag. In this case, the reader / writer device may set the resonance circuit according to the antenna, the resistance value, and the capacitance value read from the memory of the non-contact IC tag.

  Further, the resonance circuit setting database may not be provided in the reader / writer device itself, and may be connected via a network. In this way, it is possible to use a non-contact IC tag manufacturer that has previously registered parameters for changing the electromagnetic characteristics of the resonance circuit corresponding to the resonance circuit setting information.

It is a figure which shows the structure of the non-contact IC tag system in embodiment of this invention. It is a figure which shows the structure of the write processing system of the resonance circuit setting information in embodiment of this invention. It is a flowchart which shows the write-in process of the resonance circuit setting information in embodiment of this invention. It is a flowchart which shows the read-out process of the resonance circuit setting information in embodiment of this invention. It is a figure which shows the example of the database for resonance circuit settings in embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Antenna, 12 Antenna switching part, 14 Variable resistance, 16 Resistance adjustment part, 18 Capacitor, 20 Capacitor switching part, 22 Encoding circuit, 24 Modulation circuit, 26 Demodulation circuit, 28 Decoding circuit, 30 Control part, 100 Reader / writer Device, 102 RF resonance circuit, 104 peripheral circuit, 200 non-contact IC tag, 300 computer, 302 IC tag inspection device.

Claims (12)

A reader device capable of accessing a non-contact IC tag by electromagnetic means,
It has a resonance circuit that can change the electromagnetic characteristics when accessing a non-contact IC tag,
By reading the resonance circuit setting information used for setting the resonance circuit registered in advance in the non-contact IC tag to be accessed, the resonance circuit setting information read from the non-contact IC tag to be accessed is read. A reader device comprising means for changing an electromagnetic characteristic of the resonance circuit based on the base. The reader device according to claim 1,
The resonance circuit includes a variable resistance unit having a variable resistance value and a variable capacitance unit having a variable capacitance value.
By setting at least one of a resistance value of the variable resistor unit and a capacitance value of the variable capacitor unit based on resonance circuit setting information read from the non-contact IC tag to be accessed, the electromagnetic of the resonant circuit A reader device characterized by setting specific characteristics. The reader device according to claim 1 or 2,
The resonant circuit includes a plurality of antennas having different characteristics from each other,
The electromagnetic characteristics of the resonance circuit are set by selecting at least one of the plurality of antennas based on the resonance circuit setting information read from the contactless IC tag to be accessed. Reader device. The reader device according to any one of claims 1 to 3,
The reader device, wherein the resonance circuit setting information is determined based on an electromagnetic characteristic of a resonance circuit included in the non-contact IC tag and is registered in a memory built in the non-contact IC tag. The reader device according to any one of claims 1 to 4,
A parameter for controlling the electromagnetic characteristics of the resonance circuit, which is set in advance corresponding to the resonance circuit setting information, is searched, and the electromagnetic characteristics of the resonance circuit are changed using the parameters. A reader device. A non-contact IC tag comprising a built-in memory for holding electronic information and capable of accessing information held in the built-in memory from the outside by electromagnetic means,
Resonant circuit setting information used for setting electromagnetic characteristics of a resonance circuit used for access is stored in the built-in memory. The non-contact IC tag according to claim 6,
The non-contact IC tag, wherein the resonance circuit setting information is determined based on an electromagnetic characteristic of a resonance circuit included in the non-contact IC tag and registered in the built-in memory. The contactless IC tag according to claim 6 or 7,
When the resonance circuit setting information is accessed, a non-contact IC tag is transmitted with a higher output than normal data transmission. An information writing system for a non-contact IC tag capable of accessing information held in a built-in memory from outside by electromagnetic means,
An information writing system, wherein resonance circuit setting information used for setting electromagnetic characteristics of a resonance circuit used for access in the reader / writer device is written in the built-in memory. The information writing system according to claim 9,
An IC tag inspection device for measuring the electromagnetic characteristics of the resonance circuit included in the non-contact IC tag,
An information writing system, wherein the resonance circuit setting information is determined based on electromagnetic characteristics of a resonance circuit included in a non-contact IC tag measured by the IC tag inspection device. An access method for accessing a contactless IC tag by electromagnetic means,
A first step of reading resonance circuit setting information used for setting a resonance circuit registered in advance in a non-contact IC tag to be accessed;
A second step of changing the electromagnetic characteristics of the resonance circuit included in the reader device based on the resonance circuit setting information read in the first step;
An access method comprising: A method for writing information to a contactless IC tag accessible by electromagnetic means,
A writing method comprising writing resonance circuit setting information used for setting electromagnetic characteristics of a resonance circuit used for access to a built-in memory of a non-contact IC tag.

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