JP2009163656A - Wireless tag communication apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform control to shorten a time of shortening a source voltage by a wireless tag. <P>SOLUTION: A signal generation control unit outputs transmission data to a signal generating circuit, and at the same time a voltage control unit outputs an instruction signal to a voltage supply circuit so that a source voltage to be supplied to the signal generating circuit is higher than a default value. The signal generating circuit generates a carrier wave having an amplitude voltage higher than the normal one by supply of the voltage higher than the default value, and demodulates the carrier wave to generate a transmission signal. An antenna transmits an electromagnetic wave having intensity higher than normal. A wireless tag uses the electromagnetic wave to generate a driving voltage and activate it, and transmits a response signal. A receiving circuit demodulates the response signal and outputs it to the control unit. When a demodulation signal is output by the receiving circuit, the voltage control unit outputs the instruction signal to the voltage supply circuit so that the voltage to be supplied to the signal generating circuit becomes the default value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless tag communication device and a program for reading or writing information stored in a wireless tag by performing wireless communication with the wireless tag using electromagnetic waves.

  RFID tags are used in various scenes such as product management, logistics management, facility entry / exit management, railway automatic ticket gate system, etc. by introducing RFID tag system using RFID (Radio Frequency Identification) High future potential is expected in the future.

  Such an RFID wireless tag has a nonvolatile memory for storing tag information including article information, personal information, etc., and is stored by performing wireless communication using an electromagnetic wave with a reader / writer device. The tag information can be read and new information can be written.

Wireless tags are classified into a passive type that generates and activates its own driving voltage using electromagnetic waves transmitted from a reader / writer device without mounting a battery, and an active type that includes a battery. Passive wireless tags do not function when they are more than a predetermined distance away from the reader / writer device, so the range of spatial use is limited, but they are easy to miniaturize because they are not equipped with batteries, and can be produced at low cost. Used in the field. For example, Patent Document 1 discloses a technique related to a passive wireless tag.
JP 2006-40184 A

  As described above, the passive type wireless tag generates and activates the driving voltage using the electromagnetic wave transmitted from the reader / writer device. However, if it takes time to generate the driving voltage, the wireless tag is increased accordingly. Therefore, it takes a long time to start data transmission / reception with the reader / writer device, which hinders smooth work. Therefore, during the RFID tag command execution period (for example, the period during which tag information is read or written), the generation time of the RFID tag drive voltage is reduced by transmitting an unmodulated electromagnetic wave from the reader / writer device. The technique to do is described in Patent Document 1.

  However, in the case of the technique described in Patent Document 1, even when generation of the drive voltage is completed in the wireless tag, control for transmitting an unmodulated electromagnetic wave is performed during the command execution period of the wireless tag. That is, the control for transmitting an unmodulated electromagnetic wave after the generation of the drive voltage is completed is useless control and is not efficient.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a wireless tag communication apparatus and a program that efficiently perform control for shortening the generation time of the drive voltage by the wireless tag.

  A wireless tag communication device according to a first aspect of the present invention includes a reader / writer unit that supplies electric power to the wireless tag by transmitting electromagnetic waves to the wireless tag and performs wireless communication, and the reader / writer unit. In the wireless tag communication device including a reader / writer control unit that controls the operation of the wireless tag, the reader / writer unit generates an antenna that performs wireless communication with the wireless tag using electromagnetic waves, and a transmission signal that is transmitted to the wireless tag. A signal generating means for supplying power, a voltage supplying means for supplying a power supply voltage to the signal generating means, a driving means for transmitting an electromagnetic wave based on the generated transmission signal from the antenna, and an electromagnetic wave returned from the wireless tag. Receiving means for receiving, wherein the reader / writer control unit instructs the signal generating means to generate a transmission signal to be transmitted to the wireless tag. Voltage generation control means, and a voltage for controlling the power supply voltage supplied to the signal generation means to a predetermined default value and a predetermined voltage value higher than the default value. Control means, and when the signal generation means generates a transmission signal in response to a generation instruction of the transmission signal by the signal generation control means, the voltage control means supplies a power supply voltage supplied to the signal generation means. Control of switching to the predetermined voltage value higher than the default value, and the predetermined voltage value higher than the default value is supplied to the signal generating means, whereby the intensity of the electromagnetic wave transmitted from the antenna Is characterized by an increase.

  According to a fourth aspect of the present invention, there is provided a program for generating a transmission signal to be transmitted to a wireless tag from a signal generation unit to a computer, and a power supply voltage supplied to the signal generation unit in advance. Functioning as voltage control means for performing control to switch between a predetermined default value and a predetermined voltage value higher than the default value, and generating the signal in response to an instruction to generate the transmission signal by the signal generation control means When the unit generates the transmission signal, the voltage control unit is controlled to switch the power supply voltage supplied to the signal generation unit to the predetermined voltage value higher than the default value.

  According to the first and fourth aspects of the present invention, when the signal generating means generates the transmission signal, the voltage control means sets the power supply voltage supplied to the signal generating means to a voltage value higher than a predetermined default value. By switching and setting, the intensity of the electromagnetic wave transmitted from the antenna is increased, so that the wireless tag can reduce the time for generating a power supply voltage that can be driven at the start of wireless communication. Furthermore, since the start-up time of the RFID tag system can be shortened, data can be quickly transmitted and received between the RFID tag and the RFID tag communication device, and the user can read and write the RFID tag using the RFID tag communication device. Work such as processing can be performed smoothly.

  The invention according to claim 2 is the wireless tag communication device according to claim 1, wherein the voltage control means transmits the electromagnetic wave from the antenna and returns the wireless tag in response to the electromagnetic wave. When the electromagnetic wave is received by the reception unit, control is performed to switch the power supply voltage supplied to the signal generation unit to the default value.

  According to the second aspect of the present invention, when the receiving unit receives the electromagnetic wave returned by the wireless tag in response to the electromagnetic wave transmitted from the antenna, the voltage control unit sets the power supply voltage supplied to the signal generating unit as the default. Since the value is switched to the value, it is possible to prevent unnecessary voltage from being supplied to the signal generation unit and to reduce power consumption.

  A third aspect of the present invention is the wireless tag communication device according to the first or second aspect, wherein the reader / writer control unit transmits an electromagnetic wave transmitted from the wireless tag after the antenna transmits the electromagnetic wave. The apparatus further comprises presence / absence determining means for determining the presence / absence of the wireless tag in the vicinity of the antenna according to whether or not the reception means has received.

  According to the third aspect of the present invention, when the generation time of the power supply voltage of the wireless tag is shortened, the wireless tag can quickly transmit a response signal to the electromagnetic wave transmitted from the wireless tag communication device. The means can determine the presence or absence of a wireless tag near the antenna in a short time.

  According to this invention, when the signal generation means generates the transmission signal, the voltage control means switches the power supply voltage supplied to the signal generation means to a voltage value higher than a predetermined default value, thereby setting the antenna. Since the intensity of the electromagnetic wave transmitted from the wireless tag becomes high, the wireless tag can reduce the time for generating a power supply voltage that can be driven at the start of wireless communication. Furthermore, since the start-up time of the RFID tag system can be shortened, data can be quickly transmitted and received between the RFID tag and the RFID tag communication device, and the user can read and write the RFID tag using the RFID tag communication device. Work such as processing can be performed smoothly.

  Then, when the receiving unit receives the electromagnetic wave returned by the wireless tag in response to the electromagnetic wave transmitted from the antenna, the voltage control unit sets the power supply voltage supplied to the signal generating unit to a default value. It is possible to prevent an unnecessary voltage from being supplied more than necessary and to reduce power consumption.

  In addition, when the generation time of the power supply voltage of the wireless tag is shortened, the wireless tag can quickly transmit a response signal to the electromagnetic wave transmitted from the wireless tag communication device. It can be judged in a short time.

  Hereinafter, a wireless tag communication device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an electrical configuration of the wireless tag communication device 1. The wireless tag communication device 1 includes a control unit (reader / writer control unit) 11 and a reader / writer device (reader / writer unit) 2.

  The wireless tag 3 is a passive wireless tag and has a nonvolatile memory that stores tag information including article information, personal information, and the like. The wireless tag communication device 1 can perform reading of tag information stored in the nonvolatile memory and writing of new information by performing wireless communication with the antenna 31 using electromagnetic waves.

  The reader / writer device 2 includes an antenna 21, an antenna drive circuit (drive means) 22, a signal generation circuit (signal generation means) 23, a voltage supply circuit (voltage supply means) 24, and a reception circuit (reception means) 25. The The antenna 21 is for performing wireless communication using the electromagnetic wave with the antenna 31 of the wireless tag 3, and converts the transmission signal output from the antenna drive circuit 22 into an electromagnetic wave and transmits the electromagnetic wave. In addition, an electromagnetic wave transmitted from the antenna 31 of the wireless tag 3 is received, converted into an electric signal (hereinafter referred to as “reception signal”), and output to the antenna drive circuit 22.

  The antenna drive circuit 22 drives the antenna 21 based on the transmission signal generated by the signal generation circuit 23 and causes the antenna 21 to transmit electromagnetic waves. Further, the reception signal output from the antenna 31 is output to the reception circuit 25. The signal generation circuit 23 modulates a carrier wave generated by an internal oscillation circuit (not shown) based on transmission data including commands and data output from the control unit 11 to generate a transmission signal. The modulation method may be any method that can be demodulated by the wireless tag 3.

  The voltage supply circuit 24 supplies a power supply voltage to the signal generation circuit 23 according to the instruction signal output from the control unit 11. The reception circuit 25 demodulates the reception signal output from the antenna drive circuit 22 to extract reception data, and outputs the reception data to the control unit 11.

  The control unit 11 includes a CPU (Central Processing Unit) and its peripheral circuits (not shown), executes processing based on a predetermined program, and commands to the functional units constituting the reader / writer device 2 Output and data transfer are performed to control the reader / writer device 2 as a whole. The control unit 11 functions as a voltage control unit 111, a signal generation control unit 112, and a presence / absence determination unit 113.

  The signal generation control unit 112 outputs transmission data including a read command to the signal generation circuit 23 when reading tag information stored in the wireless tag 3, and transmits data including write data when writing data. Data is output to the signal generation circuit 23. The signal generation circuit 23 generates a transmission signal based on the transmission data output from the signal generation control unit 112.

  The voltage control unit 111 controls the power supply voltage supplied to the signal generation circuit 23 via the voltage supply circuit 24. Normally, the voltage control unit 111 controls the signal generation circuit 23 via the voltage supply circuit 24 so that a predetermined default voltage is supplied.

  However, when the signal generation control unit 112 outputs transmission data for instructing the signal generation circuit 23 to generate a transmission signal, the voltage control unit 112 supplies a voltage higher than the default value to the signal generation circuit 23. 111 outputs an instruction signal to the voltage supply circuit 24. For example, it is assumed that the default value of the voltage supplied to the signal generation circuit 23 is 3.3 [V]. When the signal generation control unit 112 outputs transmission data to the signal generation circuit 23, the voltage control unit 111 is supplied to the signal generation circuit 23 with a voltage higher than the default value, for example, 5.0 [V]. Outputs an instruction signal to the voltage supply circuit 24.

  The signal generation circuit 23 changes the amplitude voltage of the carrier wave generated by the oscillation circuit in accordance with the voltage supplied from the voltage supply circuit 24. An example of the carrier wave is shown in FIG. 2A shows a carrier wave generated when a voltage of a default value (3.3 [V]) is supplied from the voltage supply circuit 24, and FIG. 2B shows a default value from the power supply circuit 24. A carrier wave generated when a higher voltage (5.0 [V]) is supplied. When the voltage supplied from the voltage supply circuit 24 rises, an oscillation circuit (not shown) increases the amplitude voltage accordingly and generates a carrier wave.

  That is, when the default voltage is supplied from the voltage supply circuit 24, the signal generation circuit 23 modulates the carrier wave shown in FIG. 2A to generate a transmission signal, and the antenna is based on the generated transmission signal. 21 transmits electromagnetic waves. On the other hand, when a voltage higher than the default value is supplied from the voltage supply circuit 24, the signal generation circuit 23 modulates the carrier wave shown in FIG. 2B to generate a transmission signal, and based on the generated transmission signal The antenna 21 transmits electromagnetic waves.

  The electromagnetic wave transmitted using the carrier wave shown in FIG. 2B has higher strength as the electromagnetic wave than the electromagnetic wave transmitted using the carrier wave shown in FIG. FIG. 3 is a graph showing the relationship between the drive voltage generated by the wireless tag 3 using electromagnetic waves received by the antenna 31 and time. Graph a is a characteristic when the wireless tag 3 generates a drive voltage with the electromagnetic wave transmitted using the carrier wave shown in FIG. 2A, and graph b is transmitted using the carrier wave shown in FIG. This is a characteristic when the wireless tag 3 generates a driving voltage by the electromagnetic wave. If the voltage at which the wireless tag 3 can be driven is E [V], it takes time t2 in the case of the graph a to generate the voltage E [V], whereas in the case of the graph b, the time t1 is shorter than the time t2. You can see that the generation is complete.

  As described above, since the passive wireless tag 3 is activated by generating the driving voltage using the electromagnetic wave transmitted from the antenna 21, it takes time to generate the driving voltage. Accordingly, the system activation of the wireless tag 3 is delayed, which hinders smooth work. Therefore, when the signal generation control unit 112 outputs transmission data to the signal generation circuit 23, the voltage control unit 111 simultaneously sets the voltage supplied to the signal generation circuit 23 to a voltage higher than the default value. Is output from the antenna 21 by transmitting an instruction signal to the antenna 21 (that is, the electromagnetic wave is transmitted using a carrier wave shown in FIG. 2B). As a result, the wireless tag 3 can shorten the generation time of the drive voltage at the start of wireless communication with the wireless tag communication device 1, and can speed up the system startup. When the system is activated quickly, data transmission / reception processing between the wireless tag 3 and the wireless tag communication device 1 can be performed quickly, and the user can perform operations such as reading and writing of the wireless tag 3 using the wireless tag communication device 1. Can be done smoothly.

  Returning to FIG. When an electromagnetic wave including a command and data is transmitted from the antenna 21, the antenna 31 receives the electromagnetic wave, and the wireless tag 3 generates and activates a drive voltage, the wireless tag 3 sends a response signal to the transmitted command. The electromagnetic wave based on the response signal is generated and transmitted to the antenna 31. The antenna 21 receives the electromagnetic wave transmitted from the antenna 31 and converts it into a reception signal, and the antenna drive circuit 22 outputs the reception signal to the reception circuit 25. The receiving circuit 25 demodulates the received signal and outputs the demodulated signal to the control unit 11.

  When the demodulated signal is output from the receiving circuit 25, the control unit 11 executes various processes and the voltage control unit 111 sets the voltage supplied to the signal generation circuit 23 to a default value. An instruction signal is output to In response to this instruction signal, the voltage supply circuit 24 lowers the voltage supplied to the signal generation circuit 23 from the voltage (5.0 [V]) higher than the default value to the default value (3.3 [V]). As the voltage supplied to the signal generation circuit 23 decreases, the amplitude voltage of the generated carrier wave also decreases to the default value, and the electromagnetic wave transmitted from the antenna 21 also returns to the normal intensity.

  That is, a transmission signal is generated by the signal generation circuit 23, an electromagnetic wave is transmitted from the antenna 21 based on the transmission signal, a response signal to the electromagnetic wave is transmitted from the antenna 31, the antenna 21 receives, and the reception circuit 25 demodulates. Until the signal is input to the control unit 11, a voltage higher than the default value is supplied to the signal generation circuit 23, and accordingly, an electromagnetic wave with higher intensity than usual is transmitted from the antenna 31. After the control unit 11 inputs the demodulated signal, a voltage having a default value is supplied to the signal generation circuit 23 and an electromagnetic wave having a normal intensity is transmitted from the antenna 31. By doing so, as described above, the wireless tag 3 can shorten the generation time of the drive voltage, and prevents the signal generation circuit 23 from being supplied with unnecessary voltage more than necessary, thereby suppressing power consumption. Can do.

  The presence / absence determination unit 113 receives the transmission circuit 25 within a predetermined set time after the signal generation control unit 112 transmits transmission data to the signal generation circuit 23 (or after an electromagnetic wave is transmitted from the antenna 21). It is determined whether or not a demodulated signal has been output, and if the demodulator circuit is output within the set time, it is determined that there is a wireless tag within the communicable range, and if it is not output, the wireless signal is transmitted within the communicable range. Determine that there is no tag.

  As described above, since the high-intensity electromagnetic wave is transmitted from the antenna 21 from the start of wireless communication with the wireless tag 3, the wireless tag 3 can shorten the generation time of the drive voltage. That is, since the wireless tag 3 can transmit the response signal quickly, the presence / absence determining unit 113 can quickly determine that the wireless tag is “existing” within a communicable range. In addition, when the response signal is transmitted from the wireless tag 3 early, the setting time for determining the presence / absence can be set short, so that the presence / absence determination unit 113 also indicates that there is no wireless tag in the communicable range. Judgment can be made quickly.

  FIG. 4 is a flowchart showing an operation flow of the wireless tag communication device 1. First, the signal generation control unit 112 outputs transmission data to the signal generation circuit 23 (step S11). At the same time, the voltage control unit 111 outputs an instruction signal to the voltage supply circuit 24 so that a voltage higher than the default value is supplied to the signal generation circuit 23 (step S12). As a result, a voltage higher than the default value is supplied to the signal generation circuit 23, and the amplitude voltage of the carrier wave increases. The carrier wave is modulated to generate a transmission signal, and an electromagnetic wave is transmitted from the antenna 21 based on the transmission signal (step S13).

  The wireless tag 3 generates and activates a power supply voltage using the electromagnetic wave received by the antenna 31, generates a response signal, and outputs the electromagnetic wave from the antenna 31. The antenna 21 receives this electromagnetic wave and converts it into a received signal. The receiving circuit 25 demodulates the received signal and outputs the demodulated signal to the control unit 11. When the demodulated signal is output (step S14; YES), the voltage control unit 111 outputs an instruction signal to the voltage supply circuit 24 so that a default value voltage is supplied to the signal generation circuit 23 (step S15). . And the control part 11 performs the radio signal communication with the radio | wireless tag 3 by performing the production | generation instruction | indication of a transmission signal, control of each function part, etc. (step S16).

  On the other hand, after the signal generation control unit 112 outputs the transmission data to the signal generation circuit 23 (or after the electromagnetic wave is transmitted from the antenna 21), the response signal from the wireless tag is received within the set time, When the receiving circuit 25 does not output the demodulated signal (step S17; YES), the presence / absence determining unit 113 determines that there is no wireless tag within the communicable range (step S18). In addition, after the signal generation control unit 112 outputs the transmission data to the signal generation circuit 23 (or after the electromagnetic wave is transmitted from the antenna 21), during the set time (step S14; NO, step S17; NO ), The process of step 14 is repeated.

  As described above, when the signal generation control unit 112 outputs transmission data to the signal generation circuit 23, the voltage control unit 111 simultaneously sets the power supply voltage supplied to the signal generation circuit 23 to a voltage higher than the default value. By outputting the instruction signal to the voltage supply circuit 24 as described above, the antenna 21 transmits an electromagnetic wave having a higher intensity than usual. Therefore, the wireless tag 3 is driven when starting wireless communication with the wireless tag communication device 1. The voltage generation time can be shortened. Therefore, the activation time of the system of the wireless tag 3 can be shortened, and data transmission / reception between the wireless tag 3 and the wireless tag communication device 1 can be performed quickly. As a result, the user can smoothly perform operations such as reading and writing of the wireless tag 3 using the wireless tag communication device 1.

  In addition, when the generation time of the driving voltage of the wireless tag 3 is shortened, the wireless tag 3 can transmit a response signal quickly, so the presence / absence determining unit 113 determines the presence / absence of a wireless tag within a communicable range in a short time. be able to.

The block diagram which shows the electric constitution of a radio | wireless tag communication apparatus. The figure which showed an example of the carrier wave. The graph which showed the relationship between the power supply voltage which the wireless tag produced | generated using electromagnetic waves, and time. The flowchart which showed the flow of operation | movement of the wireless tag communication apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 RFID tag communication apparatus 11 Control part 111 Voltage control part 112 Signal generation control part 113 Presence judgment part 2 Reader / writer apparatus 21 Antenna 22 Antenna drive circuit 23 Signal generation circuit 24 Voltage supply circuit 25 Reception circuit 3 Wireless tag 31 Antenna

Claims (4)

A wireless tag communication device comprising: a reader / writer unit that supplies power to the wireless tag by transmitting electromagnetic waves to the wireless tag and performs wireless communication; and a reader / writer control unit that controls the operation of the reader / writer unit In
The reader / writer unit
An antenna for performing wireless communication with the wireless tag and electromagnetic waves;
Signal generating means for generating a transmission signal to be transmitted to the wireless tag;
Voltage supply means for supplying a power supply voltage to the signal generation means;
Driving means for transmitting an electromagnetic wave based on the generated transmission signal from the antenna;
Receiving means for receiving electromagnetic waves returned from the wireless tag;
The reader / writer control unit includes:
Signal generation control means for instructing the signal generation means to generate a transmission signal to be transmitted to the wireless tag;
Voltage control means for controlling the voltage supply means to switch the power supply voltage supplied to the signal generation means between a predetermined default value and a predetermined voltage value higher than the default value;
When the signal generation unit generates a transmission signal in response to an instruction to generate the transmission signal by the signal generation control unit, the voltage control unit sets a power supply voltage supplied to the signal generation unit higher than the default value. Control to switch to a predetermined voltage value,
The wireless tag communication device according to claim 1, wherein the signal generation means is supplied with the predetermined voltage value higher than the default value, thereby increasing the intensity of the electromagnetic wave transmitted from the antenna.   The voltage control means, when the electromagnetic wave is transmitted from the antenna and the reception means receives the electromagnetic wave returned from the wireless tag in response to the electromagnetic wave, the power supply voltage supplied to the signal generation means is the default 2. The RFID tag communication apparatus according to claim 1, wherein control for switching to a value is performed.   The reader / writer control unit determines the presence or absence of the wireless tag in the vicinity of the antenna according to whether or not the receiving unit receives the electromagnetic wave transmitted from the wireless tag after the antenna transmits the electromagnetic wave. The wireless tag communication device according to claim 1, further comprising presence / absence determining means. Computer
A signal generation control unit for generating a transmission signal to be transmitted to the wireless tag with respect to the signal generation unit;
Voltage control means for performing control to switch the power supply voltage supplied to the signal generation unit between a predetermined default value and a predetermined voltage value higher than the default value;
When the signal generator generates a transmission signal in response to the transmission signal generation instruction from the signal generation controller, the power supply voltage supplied to the signal generator is supplied to the voltage controller A program for causing a control to switch to a predetermined voltage value higher than a value.

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