JP5023965B2 - Reader / writer device and non-contact data carrier system - Google Patents

Description

The present invention relates to a stable communication with secured Ruri over Da / writer device and the non-contact data carrier system for the non-contact data carrier.

In recent years, non-contact communication technology for exchanging signals by electromagnetic induction has been established, and its use as a traffic ticket and electronic money is expanding. Further, such a non-contact communication function tends to be installed in a mobile phone, and is expected to develop further in the future. In addition to proximity communication by electromagnetic induction, IC tags that can be read and written at a distance of several meters are also commercialized in logistics. In addition, such non-contact communication technology not only enables non-contact communication but also enables power transmission at the same time, so that it can be mounted on an IC card that does not have a power source such as a battery.
If such a contactless communication function is provided, it is possible to read and write signals in a contactless manner. Therefore, in a contactless data carrier system having this contactless communication function, a reader / writer device and contactless data There is no need to bring the carrier into contact, and there is no need for a terminal or operation for making contact, and the merit that the reliability and the user's effort is reduced is evaluated.
The non-contact data carrier includes an IC card, an IC tag such as RFID (Radio frequency Identification), a mobile phone with a built-in non-contact communication function called “wallet mobile”.

In such a contactless data carrier system including a contactless data carrier and a reader / writer device, the loop antenna resonates to perform contactless communication and power transmission between the reader / writer device and the contactless data carrier. By connecting a capacitor for use and adjusting the resonance frequency determined by the constant LC of the loop antenna and the resonance capacitor to the specified frequency of the system, stable communication between the reader / writer device and the non-contact data carrier is achieved to maximize the communication distance. . However, the LC constants of the loop antenna and the resonance capacitor have some fluctuation factors and are not necessarily assumed values. For example, in a non-contact IC card, the loop antenna is made of a copper foil pattern due to low cost, and the value of L changes due to a shift in pattern width. Similarly, in order to reduce the cost, the resonance capacitor is also configured with the copper foil of the antenna substrate as an electrode and the resin of the substrate as a dielectric, and the capacitance value changes depending on the width, length, and interval of the copper foil. Furthermore, the upper and lower sides of the antenna substrate are laminated with protective films for the final use as an IC card. However, the capacitance of the capacitor changes due to this effect, so that the copper foil pattern can be adjusted as a prospective adjustment in anticipation of the frequency shift after lamination. The electrode area is adjusted by cutting, and the capacitance value of the resonance capacitor is adjusted.
Also, ambient temperature and humidity, antennas of other IC cards, influence of metal, and the like are factors that change the resonance frequency.
Due to these various factors, the resonance frequency may shift and communication may become unstable, or the communication distance may be shortened.

In response to such a problem, as a non-contact data carrier system, a response signal from the non-contact data carrier is measured by the frequency measurement unit on the reader / writer device side, and the resonance capacitor of the reader / writer device is switched or varied. In some cases, the resonance frequency of the non-contact data carrier is brought closer to the resonance frequency (see Patent Document 1).
FIG. 5 is a block diagram showing the configuration of the non-contact data carrier 300 and the reader / writer device 301 in this conventional non-contact data carrier system. The non-contact data carrier 300 includes a control circuit 301, a memory 302, a modulation / demodulation circuit 303, a loop coil 304, a resonance capacitor 305, and an output device 306. The reader / writer device 301 includes a control circuit 311, a memory 312, a modulation / demodulation circuit 313, a loop coil 314 that forms a resonance circuit, a resonance capacitor 315, an output device 316, and a measurement circuit 317.
The control circuit 301 of the non-contact data carrier 300 performs control for transmitting / receiving various data to / from the reader / writer device 301. The memory 302 stores various data transmitted / received to / from the reader / writer device 301. The modem circuit 303 is a circuit that modulates and demodulates a carrier for transmitting / receiving various data to / from the reader / writer device 301. The loop coil 304 and the resonance capacitor 305 constitute a resonance circuit whose resonance frequency is defined by the inductance value L of the loop coil 304 and the capacitance value C of the resonance capacitor 305. The output device 306 includes a display and the like.
The control circuit 311 of the reader / writer device 301 performs control for transmitting / receiving various data to / from the non-contact data carrier 300. The memory 312 stores various data transmitted to and received from the contactless data carrier 300. The modem circuit 313 is a circuit that modulates and demodulates a carrier (carrier wave) for transmitting and receiving various data to and from the non-contact data carrier 300. The loop coil 314 and the resonance capacitor 315 constitute a resonance circuit whose resonance frequency is defined by the inductance value L of the loop coil 314 and the capacitance value C of the resonance capacitor 315. The output device 316 includes a display or the like. The measurement circuit 317 is a circuit that measures a return signal from the non-contact data carrier 300. Based on the measurement value of the measurement circuit 317, the control circuit 311 switches or changes the capacitance value C of the resonance capacitor 315. Thus, the resonance frequency of the non-contact data carrier 300 is brought close to.

In addition, there is one in which a variable means is provided on the non-contact data carrier side to adjust the resonance frequency on the non-contact data carrier side (see Patent Document 2).
FIG. 6 is a block diagram showing the configuration of the reader / writer device 400 and the non-contact data carrier 401 in this conventional non-contact data carrier system. The reader / writer device 400 includes a control circuit 401, a memory 402, a modulation / demodulation circuit 403, a loop coil 404 and a resonance capacitor 405 constituting a resonance circuit, and an output device 406 including a display. The non-contact data carrier 401 includes a control circuit 411, a memory 412, a modulation / demodulation circuit 413, a loop coil 414 and a resonance capacitor 415 constituting a resonance circuit, an output device 416 including a display, and a measurement circuit 417.
The control circuit 401 of the reader / writer device 400 performs control for transmitting / receiving various data to / from the non-contact data carrier 401. The memory 402 stores various data transmitted to and received from the non-contact data carrier 401. The modem circuit 403 is a circuit that modulates and demodulates a carrier (carrier wave) for transmitting and receiving various data to and from the non-contact data carrier 401. The loop coil 404 and the resonance capacitor 405 constitute a resonance circuit whose resonance frequency is defined by the inductance value L of the loop coil 404 and the capacitance value C of the resonance capacitor 405. The output device 406 includes a display.
A control circuit 411 of the reader / writer device 401 performs control for transmitting / receiving various data to / from the reader / writer device 400. The memory 412 stores various data transmitted / received to / from the reader / writer device 400. The modem circuit 413 is a circuit that modulates and demodulates a carrier for transmitting / receiving various data to / from the reader / writer device 400. The loop coil 414 and the resonance capacitor 415 constitute a resonance circuit whose resonance frequency is defined by the inductance value L of the loop coil 414 and the capacitance value C of the resonance capacitor 415. The output device 416 includes a display and the like. The measurement circuit 417 is a circuit that measures frequency fluctuation and deviation in the non-contact data carrier 400. Based on the measurement result of the measurement circuit 417, the control circuit 411 switches the capacitance value C of the resonance capacitor 415, or By making it variable, the resonance frequency of the resonance circuit composed of the loop coil 414 and the resonance capacitor 415 is brought close to the resonance frequency at which data sent from the non-contact data carrier 400 can be received most efficiently.
JP-A-8-172378 JP-A-7-193516

However, in the conventional contactless data carrier system, particularly the contactless data carrier system shown as Patent Document 1, a communication system in which the transmission frequency can be freely set may be used. Cannot be set freely due to restrictions. In addition, when there are a plurality of non-contact data carriers, the resonance frequency is different for each non-contact data carrier, so that there is a problem that the method of adjusting the frequency on the transmission side cannot simultaneously support a plurality of non-contact data carriers.
Further, the non-contact data carrier system shown in Patent Document 2 requires a circuit for detecting and controlling frequency deviation on the non-contact data carrier side, which is required to be small and low in cost, and there are disadvantages to the user in both size and cost. There is a problem of becoming larger. Furthermore, when size and cost are prioritized, there is a problem that disadvantages due to measurement increase, for example, measurement accuracy decreases and measurement time increases.

The present invention has been made in view of such circumstances, and its object is applicable to conventional non-contact data carrier system, lapis lazuli over Da can secure stable communication with a contactless data carrier It is to provide a writer device and a contactless data carrier system.

To achieve the above object, the present invention provides communication means including an antenna for non-contact communication with a non-contact data carrier, antenna resonance frequency variable means for changing the antenna resonance frequency of the communication means, and the antenna Sweeps the antenna resonance frequency of the communication means by the resonance frequency varying means , and adjusts the frequency of the antenna contact frequency of the non-contact data carrier to correct the deviation from the reception state of the carrier transmitted from the non-contact data carrier . obtaining means for obtaining the data, and a control means for transmitting to the non-contact data carrier by the communication unit the frequency correction data obtained by the obtaining unit, the non-modulated for communication means power supply The non-contact data carrier is caused by a change in impedance of the antenna while radiating a wave. If there was a et response is determined by the control unit, the acquisition unit, the antenna resonance frequency varying means by sweeping the antenna resonance frequency of the communication means is transmitted from the non-contact data carrier when said response Provided is a reader / writer device that acquires the frequency adjustment data from the antenna resonance frequency when a peak of the received signal level of a carrier is detected.

To accomplish the above object, the reader / writer device and a contactless data carrier, the reader / writer device the non-contact data carrier supplied with electric power from the non-modulated wave radiated from said reader A non-contact data carrier system that exchanges data with a reader / writer device in a non-contact manner, wherein the non-contact data carrier includes a carrier communication means for communicating in a non-contact manner with the reader / writer device; Carrier resonance frequency correction means for changing the antenna resonance frequency of the carrier communication means, and frequency adjustment data sent from the reader / writer device for correcting the deviation of the antenna resonance frequency of the carrier communication means. DOO, the co-adjust the antenna resonant frequency of the carrier communication means by the carrier resonance frequency modifying means Comprising a frequency adjustment unit, wherein the reader / writer apparatus, a reader / writer communication means including an antenna for communicating with the contactless data carrier and the non-contact, the antenna resonance frequency of the reader / writer communication means The variable reader / writer resonance frequency correcting means, the reader / writer resonance frequency correcting means sweeps the antenna resonance frequency of the reader / writer communication means, and from the reception state of the carrier transmitted from the non-contact data carrier , comprising obtaining means for obtaining a frequency correction data, and control means for transmitting to the contactless data carrier by the frequency adjustment data obtained by the obtaining unit the reader / writer communication means, the reader / writer communication While the means is emitting unmodulated waves for power supply, the antenna impedance is When it is determined by the control means that there is a response from the non-contact data carrier due to a dance change, the acquisition means sets the antenna resonance frequency of the reader / writer communication means by the reader / writer resonance frequency correction means. Provided is a non-contact data carrier system that sweeps and acquires the frequency adjustment data from the antenna resonance frequency when a peak of a reception signal level of a carrier transmitted at the time of response is detected from the non-contact data carrier. .

According to the present invention as described above, the reader can be applied to a conventional non-contact data carrier system, can send and receive signals stably without contact, can ensure stable communication with a non-contact data carrier, and a reader / There is an effect that a writer device can be provided.
In addition, there is an effect that it is possible to provide a non-contact data carrier system that includes a reader / writer device and a non-contact data carrier that can stably exchange signals and ensure stable communication.

(First embodiment)
Next, a non-contact data carrier, a reader / writer device, and a non-contact data carrier system according to a first embodiment of the present invention will be described with reference to the drawings.
In the following description, a non-contact data carrier refers to an IC card having a non-contact communication function, an IC tag such as RFID (Radio Frequency Identification), and a mobile phone with a built-in non-contact communication function called “wallet mobile”. Includes telephones. In addition, the power is included in the non-contact data carrier regardless of any power supply method such as a method in which the power is supplied from the outside by magnetic coupling or radio waves, or a method in which the power is supplied from a built-in battery.
In the first embodiment, the power of the non-contact data carrier 1 is supplied from the reader / writer device 2 in a non-contact manner.

FIG. 1 is an explanatory diagram showing the configuration of a contactless data carrier system according to the first embodiment of the present invention.
This non-contact data carrier system includes a non-contact data carrier 1 shown in FIG. 1A and a reader / writer device 2 shown in FIG. Various data is exchanged between the non-contact data carrier 1 and the reader / writer device 2 by non-contact by using electromagnetic waves as a medium. The power of the non-contact data carrier 1 is supplied from the reader / writer device 2 in a non-contact manner using electromagnetic waves as a medium.
FIG. 2 is a block diagram showing the configuration of the non-contact data carrier 1 and the reader / writer device 2 according to the first embodiment of the present invention.
As shown in FIG. 1A, the contactless data carrier 1 includes a loop coil 11, a variable capacitance capacitor 12, a controller 13 and a power supply regulator 14 which are integrated circuits.
The loop coil 11 is formed in a rectangular shape, for example, and generates a back electromotive force in accordance with a change in magnetic flux interlinked with the loop coil 11 among magnetic fluxes radiated from the loop coil of the reader / writer device 2.
The capacitance variable capacitor 12 can employ various conventionally known circuit configurations such as a variable capacitance diode called a varicap whose capacitance can be varied by a control voltage, or a circuit whose capacitance is varied by switching a plurality of capacitors with a switch circuit. is there.
The variable capacitance capacitor 12 is connected to the loop coil 11 to form a resonance circuit. By changing the capacitance of the variable capacitance capacitor 12, the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 is increased. Adjusted.
As shown in FIG. 2, the controller 13 is constituted by a microcomputer having a modulation / demodulation circuit 131, a CPU 132, a memory 133, and the like.

The modem circuit 131 includes a modulation circuit and a demodulation circuit. The modulation circuit performs a modulation process for generating a modulated wave in which data transmitted from the non-contact data carrier 1 to the reader / writer device 2 is superimposed on the carrier. The demodulation circuit performs a demodulation process for extracting the data from the modulated wave output from the reader / writer device 2.
The CPU 132 constituting the controller 13 of the non-contact data carrier 1 detects the frequency adjustment data of the carrier detected by the reader / writer device 2 and sent to the non-contact data carrier 1 (about the antenna resonance frequency of the non-contact data carrier 1). The capacitance of the variable capacitance capacitor 12 of the resonance circuit of the non-contact data carrier 1 is adjusted by the control voltage ΔV generated based on the information).
Then, the frequency deviation between the reference resonance frequency defined in the non-contact data carrier system and the actual resonance frequency in the non-contact data carrier 1 is corrected, and the loop coil 11 and the variable capacitance capacitor 12 of the non-contact data carrier 1 are included. A function of adjusting the resonance frequency of the resonance circuit so as to coincide with the reference resonance frequency is provided.
For this reason, the frequency adjustment data of the carrier sent from the reader / writer device 2 is stored in the memory 133 of the microcomputer constituting the controller 13 of the non-contact data carrier 1.
Further, the memory 133 has a frequency adjustment in which the non-contact data carrier 1 adjusts the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 based on the frequency adjustment data sent from the reader / writer device 2. Various data including programs are stored. This frequency adjustment program is shown by the flowchart in FIG.
The power regulator 14 has a function of storing and stabilizing the power supplied to the controller 13. That is, the loop coil reception output in a predetermined frequency band centered on the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 is rectified and smoothed through a rectifying / detecting diode and a smoothing capacitor. (Ripple is removed) and supplied to the power supply regulator 14 as DC power and stored.
Then, the power supply regulator 14 converts the input DC power into a predetermined constant voltage that is stabilized and supplies it to the controller 13 as a power supply.

As shown in FIG. 1B, the reader / writer device 2 includes a loop coil 21, a variable capacitance capacitor 22, a modulation / demodulation circuit 23, a measurement circuit 24, and a control circuit constituted by a microcomputer having a CPU, a memory, and the like. 25.
The control circuit 25 is connected to an output device such as a display device 26 and an access controller 27, and an interface device.
The loop coil 21 is formed in a rectangular shape, for example, and is magnetically coupled to the loop coil 11 of the non-contact data carrier 1 so that various data such as commands and write data can be transmitted between the non-contact data carrier 1 and electromagnetic waves. Is transmitted / received via the medium, and further, electric power used by the non-contact data carrier 1 is supplied.
The variable capacitance capacitor 22 is connected to the loop coil 21 to form a resonance circuit, and the resonance frequency of the resonance circuit including the loop coil 21 and the variable capacitance capacitor 22 is adjusted by changing the capacitance of the variable capacitance capacitor 22. Is done.
The capacitance variable capacitor 22 can employ various known circuit configurations such as a variable capacitance diode called a varicap whose capacitance can be changed by a control voltage, or a circuit whose capacitance is changed by switching a plurality of capacitors with a switch circuit. is there.
The modem circuit 23 includes a modulation circuit and a demodulation circuit. The modulation circuit performs a modulation process for generating a modulated wave in which data to be transmitted from the reader / writer device 2 to the non-contact data carrier 1 is superimposed on the carrier. The demodulation circuit performs a demodulation process for extracting data from the modulated wave transmitted from the non-contact data carrier 1.
The measurement circuit 24 monitors the voltage amplitude generated in the loop coil 21, the voltage phase difference at the end of the loop coil 21, and the like, and measures the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 in the non-contact data carrier 1. Circuit.

In the first embodiment, the reader / writer device 2 detects the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 in the non-contact data carrier 1.
When the detected resonance frequency of the resonance circuit on the non-contact data carrier 1 side is shifted from the reference resonance frequency, the resonance frequency on the non-contact data carrier 1 side is changed from the reader / writer device 2 to the non-contact data carrier 1. Data for frequency adjustment which is deviation information with respect to the reference resonance frequency is transmitted.
In the non-contact data carrier 1, frequency adjustment processing of the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 in the non-contact data carrier 1 is performed based on the frequency adjustment data.
As shown in FIG. 2, the control circuit 25 of the reader / writer device 2 is a microcomputer including a CPU 251, a memory 252, and the like. The memory 252 includes a reader / writer for resonance frequency adjustment processing in the non-contact data carrier 1. Various data including a frequency adjustment program on the writer device 2 side are stored. The frequency adjustment program on the reader / writer device 2 side is shown in the flowchart of FIG.

Next, the operation will be described.
FIG. 3 is a flowchart showing a frequency adjustment program in which the non-contact data carrier 1 adjusts the resonance frequency of the resonance circuit based on the frequency adjustment data sent from the reader / writer device 2. FIG. 4 is a flowchart showing a frequency adjustment program on the reader / writer device 2 side for the resonance frequency adjustment processing of the non-contact data carrier 1.
The operation of the contactless data carrier, reader / writer device, and contactless data carrier system of the first embodiment will be described below with reference to FIGS.
The non-contact data carrier system according to the first embodiment includes a reader / writer device 2 in which the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitor 12 on the non-contact data carrier 1 side is changed from the reference resonance frequency. A deviation is detected, and frequency adjustment data for correcting this deviation is sent from the reader / writer device 2 to the non-contact data carrier 1.
On the non-contact data carrier 1 side, the deviation of the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 from the reference resonance frequency is also included in the frequency adjustment data sent from the reader / writer device 2. And correct it.
The reference resonance frequency is defined in advance for the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 of the non-contact data carrier 1 and the resonance circuit including the loop coil 21 and the variable capacitance capacitor 22 of the reader / writer device 2. This is the reference value that is being used. The carrier frequency also matches this reference resonance frequency.

First, the operation of the reader / writer device 1 will be described.
In the reader / writer device 1, a command and necessary write data are radiated from the loop coil 21 as electromagnetic waves, and a non-modulated wave is radiated for a certain period. That is, the modulation / demodulation circuit 23 is controlled by the CPU 251 of the control circuit 25 so as to apply a voltage signal corresponding to a modulation wave having a predetermined frequency to the loop coil 117 according to a predetermined program.
The modulation circuit of the modem circuit 23 includes a carrier generator that generates a carrier having a predetermined frequency (for example, a reference resonance frequency of 14 MHz), and a drive circuit (amplifier) whose amplification factor changes under the control of the CPU 251. The drive circuit is configured to receive a carrier from the carrier generator.
The amplification factor of the drive circuit is controlled by the CPU 251 in accordance with a command to be transmitted to the non-contact data carrier 1 and write data. For this reason, in the drive circuit, the carrier generated by the carrier generator is amplitude-modulated by a command or write data to be transmitted to the non-contact data carrier 1 and output.
An output terminal of the drive circuit is connected to the loop coil 21. Therefore, the amplitude-modulated wave output from the drive circuit is supplied to the loop coil 21. That is, a voltage signal corresponding to the amplitude modulation wave is applied to the loop coil 21. As a result, a current corresponding to the voltage flows in the loop coil 21, and a magnetic flux (magnetic field) corresponding to the change in the current is generated.
That is, the loop coil 21 emits an amplitude-modulated wave with a predetermined frequency output from the drive circuit as an electromagnetic wave.
In the reader / writer device 2, the CPU 251 controls the amplification factor of the drive circuit to be a constant value, and thereby, an unmodulated wave having a predetermined frequency is radiated from the loop coil 21 as an electromagnetic wave.
As a result, in the non-contact data carrier 1, the loop coil reception output in a predetermined frequency band centered on the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 is a rectifying / detecting diode and a smoothing diode. By passing through the capacitor, it is rectified and smoothed (ripple is removed) and supplied to the power supply regulator 14 as DC power and stored. The contactless data carrier 1 will respond to the reader / writer device 2 using this power.

The reader / writer device 2 determines whether or not there is a response from the non-contact data carrier 1. Whether or not there is a response from the non-contact data carrier 1 is determined as follows.
That is, in the non-contact data carrier 1, the loop coil 11 and the variable capacitance capacitor 12 are connected in parallel to form a resonance circuit. The variable capacitance capacitor 12 is configured by connecting a plurality of series circuits of an adjustment capacitor and a switch (for example, an FET) to a resonance capacitor in parallel. Accordingly, when the switch is turned on / off and the number of adjustment capacitors connected in parallel to the resonance capacitor is changed, the resonance frequency of the resonance circuit in which the loop coil 11 and the variable capacitance capacitor 12 are connected in parallel changes. .
In the non-contact data carrier 1, when responding to the reader / writer device 2, a control signal for changing the capacitance of the variable capacitance capacitor 12 is turned on / off. As a result, the switch is turned on / off, and the resonance frequency (impedance) of the resonance circuit constituted by the loop coil 11 and the variable capacitance capacitor 12 changes.
In this case, it is assumed that the non-contact data carrier 1 and the reader / writer device 2 are at a distance that causes mutual induction between the loop coil 11 and the loop coil 21.
At this time, the impedance when the loop coil 21 side is viewed from the connection point (terminal of the loop coil) between the drive circuit of the reader / writer device 2 that emits the electromagnetic wave corresponding to the unmodulated wave and the loop coil 21 is non-contact data. It changes corresponding to ON / OFF of the switch of the carrier 1.
Therefore, when there is a response from the non-contact data carrier 1, the voltage at the connection point of the loop antenna 21 at this time also changes.
The voltage at the connection point of the loop antenna 21 is detected and demodulated by the modulation / demodulation circuit 23 and supplied to the CPU 251 of the control circuit 25. That is, the CPU 251 determines whether or not there is a response from the non-contact data carrier 1 based on the demodulated signal output from the modulation / demodulation circuit 23.
When the CPU 251 of the reader / writer device 2 determines that there is no response from the non-contact data carrier 1, the amplitude-modulated wave and the non-modulated wave are radiated as described above until there is a response from the non-contact data carrier 1. This process is repeated.
On the other hand, when the CPU 251 of the reader / writer device 2 determines that there is a response from the non-contact data carrier 1, necessary processing is performed based on the demodulated signal output from the modem circuit 23.
For example, when the necessary processing is applied to an automatic ticket gate system, the CPU 251 controls the display 26, the access controller 27, and other devices.

On the other hand, the measurement circuit 24 of the reader / writer device 2 monitors the amplitude of the voltage induced in the loop coil 21 and the voltage phase difference at the end of the loop coil. For example, a response is returned from the non-contact data carrier 1. When the carrier is sent from the non-contact data carrier 1, the resonance frequency of the resonance circuit including the loop coil 21 and the variable capacitance capacitor 22 is varied to detect the peak of the reception signal level. The frequency when the peak, that is, the resonance point is detected is measured by the frequency measurement circuit.
This measured frequency corresponds to the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 on the non-contact data carrier 1 side.
Therefore, the difference between the frequency measured when the peak of the received signal level, that is, the resonance point is detected, and the reference resonance frequency corresponds to the deviation of the resonance frequency of the resonance circuit in the non-contact data carrier 1.
Therefore, the frequency adjustment data (information about the antenna resonance frequency) for correcting the resonance frequency shift of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 on the non-contact data carrier 1 side is transferred to the reader / writer device. 2 to the contactless data carrier 1.
In the non-contact data carrier 1, the resonance frequency shift of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 is adjusted based on the frequency adjustment data sent from the reader / writer device 2.
As a result, the resonance frequency of the resonance circuit on the non-contact data carrier 1 side coincides with the reference resonance frequency, and efficient and always stable communication between the non-contact data carrier 1 and the reader / writer device 2 is automatically performed. Can be secured.

Next, frequency adjustment processing in the non-contact data carrier 1 and the reader / writer device 2 will be described with reference to the flowcharts of FIGS.
The carrier is detected in the non-contact data carrier 1, the power source of the non-contact data carrier 1 is established and the CPU 132 is started up, and the reply is sent from the non-contact data carrier 1 to the reader / writer device 2 Then, frequency adjustment processing is started in the reader / writer device 2 and the non-contact data carrier 1.
When the frequency adjustment processing is started in the reader / writer device 2, as shown in the flowchart of FIG. 4, first, signal level peak point detection is performed for a carrier from the non-contact data carrier 1 in a narrow frequency range within the communication regulations. A frequency sweep (narrowband mode) is performed (step S11).
This frequency range is set to a range that does not cause a significant problem in system performance even if a frequency shift occurs, such as ± 200 kHz with respect to the center frequency of 13.56 MHz.
Further, this frequency sweep detects the signal level output from the loop coil 21 while varying the capacitance of the capacitance variable capacitor 22 of the resonance circuit in the reader / writer device 2 and varying the resonance frequency of the resonance circuit. The peak of the change in the received signal level due to the impedance effect of the resonance circuit composed of the capacitor 22 and the capacitance variable capacitor 22 is detected. A resonance point is derived (step S12).
As another method, the resonance point of the resonance circuit on the non-contact data carrier 1 side may be derived from the point where the signal phase difference between the ends of the loop antenna 21 of the reader / writer device 2 becomes zero.
When this resonance point is derived in the narrow frequency sweep, it is next determined whether or not the maintenance mode is set (step S15). As a result, when the maintenance mode is not set, the routine proceeds to normal processing (step S20). When shifting to this normal processing, the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 of the non-contact data carrier 1 is in the frequency range, and the reference resonance of the resonance frequency of the resonance circuit is included. Since there is no frequency error, the resonance frequency of the resonance circuit in the non-contact data carrier 1 is not adjusted (resonance frequency adjustment path mode). In the maintenance mode in step S15, the resonance frequency on the non-contact data carrier 1 side is determined from the frequency measured in the measurement circuit 24 (step S16), and the determined resonance frequency, that is, the measured frequency and the reference resonance frequency are used. Data for frequency adjustment of the non-contact data carrier 1 is calculated (step S17). In this calculation, a difference (deviation information) between the reference resonance frequency and the measured frequency (antenna resonance frequency of the non-contact data carrier 1) is obtained. Then, the frequency adjustment data calculated in this way is transmitted to the non-contact data carrier 1 (step S18), and a reply from the non-contact data carrier 1 is awaited (step S19).

  If the resonance point cannot be detected by sweeping in a narrow band in the processes in steps S11 and S12, a sweep in a wide band (wideband mode) having a wider sweep frequency range is executed (step S13). As a result, when the resonance point can be detected within the time, the frequency is measured as described above (step S16), the frequency adjustment data is calculated (step S17), and transmitted (step S18). If the resonance point cannot be detected within the time, the process proceeds to error processing (step S21). In error processing, detection may be performed a plurality of times, or frequency adjustment processing may be terminated.

On the other hand, in the non-contact data carrier 1, as shown in the flowchart of FIG. 3, the resonance frequency of the resonance circuit is not adjusted when the communication with the reader / writer device 2 is first secured. First, normal signal processing is executed (step S2). Then, the non-contact data carrier 1 sets the frequency adjustment data for shifting to the frequency adjustment mode from the reader / writer device 2 in advance when communication with the reader / writer device 2 is ensured. It is determined whether it has been received (step S3). As a result, if frequency adjustment data is not received within the preset time, normal signal processing is performed and frequency adjustment is not performed. On the other hand, when the frequency adjustment data is received, it is determined whether or not the master mode calculates the optimum value by itself (step S4). As a result, when the master mode is set, the adjustment data is recalculated based on the received frequency adjustment data (step S5). When the master mode is not set, that is, in the slave mode, the received frequency adjustment data is stored in the memory 133 (step S6), and the loop coil is applied by applying a control voltage to the variable capacitance capacitor 12. The resonance frequency of the resonance circuit composed of 11 and the variable capacitance capacitor 12 is adjusted (step S7). At this time, the frequency adjustment data is converted into data for a D / A converter built in the CPU 132 that generates a control voltage applied to the variable capacitance capacitor 12. That is, if ΔV is a control voltage applied to the variable capacitance capacitor 12, this control voltage ΔV is converted from (reference resonance frequency−measurement frequency) / (frequency change / voltage of frequency control circuit) to D / A converter data. Can be calculated. The absolute value of the control voltage may be calculated as a difference.
The non-contact data carrier 1 transmits adjustment end data for notifying the reader / writer device 2 of the end of adjustment after applying the control voltage, and ends the frequency adjustment process (step S8).

In the maintenance mode, adjustment is possible even with a slight deviation, which is effective when there is no restriction on processing time at the time of factory shipment or maintenance.
Further, in the master mode, it is possible to use individual coefficients held in the non-contact data carrier 1 instead of the standard values held in the reader / writer device 2 for the frequency change / voltage coefficients of the frequency control circuit. More precise adjustment is possible. In some cases, the system may intentionally shift the carrier frequency to a high frequency so that communication can be ensured even when there are multiple non-contact data carriers. It becomes.

  In addition, by making the variable range of the variable capacitor that determines the frequency adjustment range wider in the reader / writer device 2 than in the non-contact data carrier 1, the control circuit 13 of the non-contact data carrier 1 has a wide bandwidth regardless of the state. The resonance point can be detected by sweeping.

  When the non-contact data carrier 1 is started up, it reads out the frequency control data stored in the memory, initializes the output of the D / A converter, and then establishes communication with the transmission signal from the reader / writer device 2 Wait for it. When a non-contact data carrier, particularly an IC card, does not have its own power supply, initialization is performed after generating a power supply voltage by receiving a transmission signal of the reader / writer device 2. Therefore, the variable range must be designed so that the frequency shift at zero control voltage is reduced to some extent.

  In the above description, power is supplied from the reader / writer device 2 to the contactless data carrier 1, but the power of the contactless data carrier is supplied from a battery built in the contactless data carrier itself. It may be a thing.

  In the above description, the carrier is amplitude-modulated by a command or write data and is transmitted / received between the non-contact data carrier 1 and the reader / writer device 2, but the modulation method is limited to amplitude modulation. However, other modulation schemes can be applied.

  In the above description, the reader / writer device 2 calculates the difference between the reference resonance frequency and the measured frequency (antenna resonance frequency of the non-contact data carrier 1), and frequency adjustment is performed on the deviation information thus calculated. Although it has been described that data is transmitted to the non-contact data carrier 1 as the data for use, the measured frequency, that is, the antenna resonance frequency of the non-contact data carrier 1 is transmitted to the non-contact data carrier 1, and the difference from the reference resonance frequency is contactless It may be configured to calculate in the data carrier 1.

As described above, according to the first embodiment, the reader / writer device 2 detects the deviation of the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 in the non-contact data carrier 1. The frequency adjustment data obtained in this way is transmitted from the reader / writer device 2 to the non-contact data carrier 1, and the non-contact data carrier 1 uses the frequency adjustment data to resonate its own resonance circuit. Adjust the frequency shift. Therefore, even if the resonance frequency of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 in the non-contact data carrier 1 is deviated from the reference resonance frequency due to various factors, the resonance circuit of the non-contact data carrier 1 side The resonance frequency coincides with the reference resonance frequency, and there is an effect that efficient and stable communication can always be automatically ensured between the non-contact data carrier 1 and the reader / writer device 2.
Also, the reader / writer device according to the first embodiment is conventional if the resonance frequency and modulation method of the resonance circuit including the loop coil 21 and the variable capacitance capacitor 22 are the same as those of the conventional non-contact data carrier. Since it is possible to communicate with the non-contact data carrier of the non-contact data carrier system of the present invention, it is possible to provide a reader / writer device that can be used in combination with the non-contact data carrier of the conventional non-contact data carrier system There is.
Further, the non-contact data carrier 1 according to the first embodiment has the same resonance frequency and modulation method of the resonance circuit including the loop coil 11 and the variable capacitance capacitor 12 as those of the conventional reader / writer device. Since it is possible to communicate with a reader / writer device of a conventional contactless data carrier system, it is possible to provide a contactless data carrier that can be used in combination with a reader / writer device of a conventional contactless data carrier system. effective.

It is explanatory drawing which shows the structure of the non-contact data carrier system by the 1st Embodiment of this invention. It is a block diagram which shows the structure of the non-contact data carrier and reader / writer apparatus by the 1st Embodiment of this invention. It is a flowchart which shows the frequency adjustment program by the side of the non-contact data carrier in the 1st Embodiment of this invention. It is a flowchart which shows the frequency adjustment program by the side of the reader / writer apparatus in the 1st Embodiment of this invention. It is a block diagram which shows the structure of the non-contact data carrier and reader / writer apparatus in the conventional non-contact data carrier system. It is a block diagram which shows the structure of the reader / writer apparatus and the non-contact data carrier in the conventional non-contact data carrier system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Non-contact data carrier, 2 ... Reader / writer apparatus, 11 ... Loop coil (communication means, carrier communication means), 12 ... Capacitance variable capacitor (communication means, carrier communication means), 21 ... Loop coil (Communication means, reader / writer communication means), 22... Capacitance variable capacitor (communication means, reader / writer communication means), 23... Modulation / demodulation circuit (communication means, reader / writer communication means), 24. 131... Modulation / demodulation circuit (communication means, carrier communication means), 132... CPU (antenna resonance frequency variable means, resonance frequency adjustment means, carrier resonance frequency correction means), 251 ... CPU (antenna resonance frequency variable means, acquisition means) , Control means, reader / writer resonance frequency correction means).

Claims (6)

Communication means including an antenna for non-contact communication with a non-contact data carrier;
Antenna resonance frequency variable means for changing the antenna resonance frequency of the communication means;
Sweeping the antenna resonance frequency of the communication unit by the antenna resonance frequency varying means, the frequency of the reception state of the carrier transmitted, to correct the deviation of the antenna resonance frequency of the non-contact data carrier from the non-contact data carrier Obtaining means for obtaining adjustment data ;
Control means for transmitting the frequency adjustment data acquired by the acquisition means to the non-contact data carrier by the communication means;
Equipped with a,
When the control means determines that there is a response from the non-contact data carrier due to a change in impedance of the antenna while the communication means radiates an unmodulated wave for power supply, The acquisition means sweeps the antenna resonance frequency of the communication means by the antenna resonance frequency variable means, and detects the peak of the received signal level of the carrier transmitted during the response from the non-contact data carrier. To obtain the frequency adjustment data ,
Li over reader / writer device. It said frequency adjustment data, the relative continuous wave, a pre-Symbol detected the deviation information with respect to a reference resonance frequency of the antenna resonant frequency of the non-contact data carrier when said response from the contactless data carrier is returned,
The reader / writer device according to claim 1 . Said frequency adjustment data, the relative continuous wave, frequency information indicating the pre-Symbol antenna resonant frequency measured from the carrier transmitted from the non-contact data carrier when the reply from the contactless data carrier is returned Is ,
Reader / writer apparatus according to 請 Motomeko 1. The antenna resonance frequency varying means is configured to sweep the antenna resonance frequency within a range that falls within communication regulations, and when the peak of the received signal level cannot be detected in the narrowband mode, the narrowband mode A wideband mode that sweeps the antenna resonance frequency within a wider range ,
Reader / writer apparatus according to 請 Motomeko 2 or 3. The antenna of the non-contact data carrier when the acquisition means changes the antenna resonance frequency of the communication means within the narrowband mode by the antenna resonance frequency variable means in order to acquire the frequency adjustment data. When the resonance frequency is within the range of the narrowband mode, the resonance frequency adjustment path mode in which the adjustment of the antenna resonance frequency of the communication device in the non-contact data carrier is not performed ,
Reader / writer apparatus according to 請 Motomeko 4. A reader / writer device and a non-contact data carrier; receiving power from an unmodulated wave radiated from the reader / writer device ; Is a non-contact data carrier system for sending and receiving
The contactless data carrier is:
Carrier communication means for performing contactless communication with the reader / writer device;
Carrier resonance frequency correction means for changing the antenna resonance frequency of the carrier communication means;
Based on the frequency adjustment data sent from the reader / writer device for correcting the deviation of the antenna resonance frequency of the carrier communication means, the carrier resonance frequency correction means performs the antenna resonance frequency of the carrier communication means. a resonance frequency adjustment means for adjusting the,
With
The reader / writer device
Reader / writer communication means including an antenna for performing contactless communication with the contactless data carrier;
Reader / writer resonance frequency correcting means for changing the antenna resonance frequency of the reader / writer communication means;
An acquisition means for sweeping an antenna resonance frequency of the reader / writer communication means by the reader / writer resonance frequency correcting means and acquiring the frequency adjustment data from a reception state of a carrier transmitted from the non-contact data carrier;
Control means for transmitting the frequency adjustment data acquired by the acquisition means to the non-contact data carrier by the reader / writer communication means;
Equipped with a,
While the reader / writer communication means is radiating an unmodulated wave for power supply, the control means determines that there is a response from the non-contact data carrier due to a change in impedance of the antenna. And the acquisition means sweeps the antenna resonance frequency of the reader / writer communication means by the reader / writer resonance frequency correction means, and obtains the peak of the received signal level of the carrier transmitted at the time of response from the non-contact data carrier. The frequency adjustment data is obtained from the antenna resonance frequency when detected.
Non- contact data carrier system.

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