WO2009154032A1

WO2009154032A1 - Radio tag

Info

Publication number: WO2009154032A1
Application number: PCT/JP2009/056446
Authority: WO
Inventors: 毅宮林; 豊和井上
Original assignee: ブラザー工業株式会社
Priority date: 2008-06-18
Filing date: 2009-03-30
Publication date: 2009-12-23
Also published as: JP2010002971A

Abstract

In a radio tag provided with a light-emitting diode for receiving an AC transmission signal transmitted from a reader/writer as an AC received signal, power supply (2115) of the radio tag consists of an N-fold voltage rectifier circuit (2115a) in which one or more double voltage rectifier circuits are connected. As a result, even if the AC received signal is a faint signal, the power supply (2115) raises and rectifies the AC voltage at the time of reception obtained from the AC received signal, thus allowing the light-emitting diode to emit light.

Description

Wireless tag

The present invention relates to a wireless tag including a light emitting diode.

Conventionally, when a plurality of articles are located in close proximity, in order to search for articles desired by the user, a wireless tag equipped with a light emitting diode is attached to each article, and a reader / writer There has been proposed a technique for performing light communication with each wireless tag to emit light from a light emitting diode of the wireless tag attached to an article desired by a user (for example, Patent Document 1).

Specifically, the user uses a reader / writer to externally transmit a radio wave including a search ID code indicating an ID code of a wireless tag to be searched (hereinafter, a radio wave transmitted from the reader / writer is referred to as an AC transmission signal). And each wireless tag receives the AC transmission signal as an AC reception signal. Each wireless tag stores a storage ID code that is an ID code for identifying itself. Each wireless tag collates whether or not the search ID code included in the AC reception signal and the stored ID code stored in the radio tag satisfy a predetermined relationship. The light emitting diode provided in itself emits light, and if it cannot be verified, it does not emit light. As a result, the user can easily search for an article desired by the user using the wireless tag that emits light.
JP 2006-24018 A

By the way, the AC transmission signal attenuates as the propagation distance becomes longer. That is, as the distance between the reader / writer and the wireless tag becomes longer, the AC reception signal received by the wireless tag becomes a weak signal. In some cases, the AC transmission signal may be a weak signal from the viewpoint of power suppression or from the viewpoint of suppressing radio wave interference. In this case, since the AC transmission signal is a weak signal, the AC reception signal further becomes a weak signal.

On the other hand, the predetermined drive voltage necessary for driving the light emitting diode is larger than the AC voltage at the time of reception obtained from the AC reception signal. Therefore, when the AC reception signal becomes a weak signal due to a long distance between the reader / writer and the wireless tag or because the AC transmission signal is a weak signal, the light emitting diode may be caused to emit light. There are things that cannot be done.

An object of the present invention is to provide a wireless tag having a light emitting diode that can cause the light emitting diode to emit light even when the AC reception signal is a weak signal.

According to the present disclosure, the wireless tag is a wireless tag that performs wireless communication with a reader / writer that transmits an AC transmission signal to the outside, and the AC tag receives the AC transmission signal transmitted from the reader / writer. A reception antenna that receives the signal, a light emitting diode that emits light when a predetermined drive voltage greater than the reception AC voltage indicating the AC voltage obtained from the AC reception signal is applied in the forward direction, and the reception antenna. A boost rectifier circuit that boosts the received AC voltage and rectifies the received AC voltage to a DC voltage so that the received AC voltage obtained from the AC received signal received by the receiving antenna is equal to or higher than the predetermined drive voltage; A charging circuit in which at least a part of the boosted rectified voltage boosted by the boost rectifier circuit and rectified to a DC voltage is charged; The boosting rectified voltage is connected between the receiving antenna and the boosted rectified voltage is suppressed from being discharged to the receiving antenna side, and the boosting voltage is charged to the charging circuit to be equal to or higher than the predetermined driving voltage. A transmission circuit for transmitting a rectified voltage to the charging circuit; and a charging voltage discharging means for discharging the charging voltage so that the charging voltage charged in the charging circuit is applied in a forward direction of the light emitting diode. It is characterized by that.

According to the present disclosure, the AC transmission signal includes a search ID code indicating an ID code of a wireless tag that a user wants to search, and the wireless tag includes an ID code storage unit that stores a storage ID code; Checking whether or not to check whether or not the search ID code included in the AC reception signal received by the receiving antenna and the stored ID code stored in the ID code storage means satisfy a predetermined relationship. The charging voltage discharging means may stop discharging of the charging voltage when the verification availability determination means determines that the verification is not successful.

The step-up rectifier circuit may be a circuit in which one or a plurality of voltage doubler rectifier circuits configured by using a diode and a capacitor, which substantially doubles an input AC voltage and rectifies and outputs a DC voltage, are connected. good.

Further, the boosted rectified voltage is gradually charged into the charging circuit, and the charging voltage discharging means discharges the charging voltage at a predetermined timing after the charging voltage becomes equal to or higher than the predetermined driving voltage. You may make it do.

Further, the charging voltage discharging means may monitor the value of the charging voltage and discharge the charging voltage at a timing when the value of the charging voltage reaches the predetermined driving voltage.

Further, an expected charging time in which the charging voltage is expected to be the predetermined driving voltage is determined in advance with reference to a time when the receiving antenna receives the AC reception signal, and the charging voltage discharging means The charging voltage may be discharged at the timing of charging time. Further, the transmission circuit may be constituted by a resistance element.

The boost rectifier circuit gradually boosts the reception AC voltage, and the transmission circuit is turned on when a voltage equal to or higher than a predetermined Zener voltage is applied to both ends, the boost rectifier circuit, A transistor that is connected between the charging circuits and controls the conduction and interruption of the current and amplifies the input current, and when the voltage gradually boosted by the boost rectifier circuit becomes equal to or higher than the Zener voltage, The Zener diode and the transistor may be connected so that the transistor becomes conductive.

6 is a diagram illustrating an example of a method of using wireless tags 201 to 209. FIG. 2 is a block diagram illustrating an electrical configuration of a reader / writer 10. FIG. 1 is an external view of a wireless tag 201. FIG. 2 is a block diagram showing an electrical configuration of a wireless tag 201. FIG. 3 is a block diagram showing an electrical configuration of a power supply 2115. FIG. FIG. 11 is a cross-sectional view of the light emitting diode 231 for explaining a process of providing the light emitting diode 231 on the substrate 241. 6 is a flowchart showing a reader / writer control process executed by the control unit 12 of the reader / writer 10. It is the flowchart which showed the radio tag control processing which CPU2111a performs. It is the block diagram which showed the electrical structure of the wireless tag 251 in 2nd Embodiment. It is the flowchart which showed the radio tag control processing which CPU2117a executes. It is the block diagram which showed the electric constitution of the wireless tag 261 in 3rd Embodiment. 3 is a block diagram showing an electrical configuration of a power supply 2118. FIG. It is a graph for demonstrating the time change of the charging voltage charged to the capacitor | condenser Ca. It is a figure for demonstrating the wireless tag system provided with the wireless tag 271, the reader / writer 70, and the server 80 in 4th Embodiment.

(First embodiment)
Hereinafter, a first embodiment of a wireless tag according to the present disclosure will be described with reference to the drawings. As shown in FIG. 1, the wireless tags 201 to 209 are attached to the books 101 to 109 stored in the book box 20. The wireless tags 201 to 209 each store a storage ID code that is an individual ID code for identifying itself. Further, each of the wireless tags 201 to 209 includes a light emitting diode. On the other hand, the reader / writer 10 is a device for searching for the wireless tags 201 to 209 attached to the books 101 to 109 desired by the user. The reader / writer 10 includes an input unit 11 for inputting the storage ID codes of the wireless tags 201 to 209 attached to the books 101 to 109 that the user desires to search.

When the user wants to search for any of the books 101 to 109, the user operates the input unit 11 of the reader / writer 10 to store the storage IDs of the wireless tags 201 to 209 attached to the books 101 to 109 to be searched. A search ID code corresponding to the code is input and the transmission switch is operated. The reader / writer 10 transmits an AC transmission signal 50 including a search ID code input by the user to the outside. Each of the wireless tags 201 to 209 receives the AC transmission signal 50 as an AC reception signal 60. Each of the wireless tags 201 to 209 determines whether or not the search ID code included in the AC reception signal 60 matches the stored ID code stored in itself. As a result, when it is determined that they match, the light emitting diode emits light, and when it is determined that they do not match, the light emitting diode does not emit light. Then, the user can easily find any of the wireless tags 201 to 209 that emit light from the light emitting diode, that is, any of the books 101 to 109 desired by the user.

Next, the configuration of the reader / writer 10 will be described. As shown in FIG. 2, the reader / writer 10 includes an input unit 11, a control unit 12, a display unit 13, a power supply 14, a modulation unit 15, a demodulation unit 16, and a transmission / reception antenna 17.

As described above, the input unit 11 inputs the search ID code corresponding to the storage ID code of the wireless tags 201 to 209 desired by the user, and searches for the wireless tags 201 to 209 input by the input switch. A transmission switch for inputting a transmission instruction signal for transmitting an AC transmission signal including an ID code to the outside is provided. The input unit 11 is connected to the control unit 12, and the search ID code and the transmission instruction signal input from the input unit 11 are input to the control unit 12.

The control unit 12 executes a reader / writer control process to be described later. The control unit 12 has a CPU, a ROM, and a RAM (not shown). The ROM stores a program for executing the reader / writer control process, and the CPU executes the reader / writer control process according to the program stored in the ROM. The RAM plays a role of temporarily storing information in the process of executing the reader / writer control process. Details of the reader / writer control process will be described later with reference to a flowchart.

The display unit 13 is composed of a liquid crystal display, and displays a storage ID code input from the input unit 11 or displays that when the control unit 12 receives a reply signal from the wireless tags 201 to 209. To do. Note that an organic EL display or a plasma display may be used as the display unit 13 instead of the liquid crystal display.

The power source 14 is connected to the control unit 12 and has an on / off switch (not shown). When the on / off switch is operated and turned on by the user, the power supply 14 supplies a predetermined DC voltage to the control unit 12 in order to drive the control unit 12. On the other hand, when the on / off switch is operated by the user to be turned off, the supply of voltage to the control unit 12 by the power supply 14 is stopped.

The modulation unit 15 is connected to the control unit 12. The modulation unit 15 modulates the search ID code transmitted from the control unit 12 into an AC transmission signal 50 that can be transmitted to the outside, and outputs the AC transmission signal 50. The modulation unit 15 is connected to the transmission / reception antenna 17, and the AC transmission signal 50 output from the modulation unit 15 is transmitted from the transmission / reception antenna 17 to the outside.

The demodulator 16 is connected to the transmission / reception antenna 17 and receives return signals from the wireless tags 201 to 209 received by the transmission / reception antenna 17. Then, the demodulator 16 demodulates the reply signal and inputs the demodulated signal to the controller 12. In the present embodiment, the return signal is a signal indicating that the search ID code included in the AC transmission signal 50 matches the stored ID code stored in the wireless tags 201 to 209.

Next, the configuration of the wireless tags 201 to 209 will be described. Note that the wireless tags 201 to 209 differ only in the stored ID code and have the same structure. Hereinafter, the configuration of the wireless tag 201 will be described as a representative.

As shown in FIG. 3, the wireless tag 201 is provided with a coiled transmitting / receiving antenna 221 on the outer periphery of a rectangular substrate 241. A chip 211 is connected to the transmission / reception antenna 221. The substrate 241 is provided with a thin film light emitting diode 231. The substrate 241 is a polyethylene terephthalate (PET) film, and the light emitting diode 231 is an organic EL.

As shown in FIG. 4, the wireless tag 201 includes a transmission / reception antenna 221, a chip 211, and a light emitting diode 231. The transmission / reception antenna 221 receives the AC transmission signal 50 transmitted from the reader / writer 10 as the AC reception signal 60. The transmission / reception antenna 221 is connected to the chip 211 and inputs the received AC reception signal 60 to the chip 211. Further, when the reply signal is output from the chip 211, the transmission / reception antenna 221 transmits the reply signal to the outside.

As shown in FIG. 4, the chip 211 includes a storage unit 2112, a demodulation unit 2113, a modulation unit 2114, a power source 2115, a light emitting diode drive driver 2116, and a control unit 2111 connected thereto.

The storage unit 2112 stores a storage ID code. The demodulator 2113 is connected to the transmission / reception antenna 221 and demodulates the AC reception signal 60 transmitted from the transmission / reception antenna 221. The demodulator 2113 is connected to the controller 2111 and inputs the demodulated signal to the controller 2111. Modulation section 2114 is connected to control section 2111, modulates the reply signal input from control section 2111 into a format that can be transmitted to the outside, and outputs the modulated reply signal. The modulation unit 2114 is connected to the transmission / reception antenna 221, and the reply signal output from the modulation unit 2114 is transmitted from the transmission / reception antenna 221 to the outside.

The power supply 2115 is connected to the transmission / reception antenna 221, and rectifies the reception AC voltage obtained from the AC reception signal 60 received by the transmission / reception antenna 221 into a DC voltage. The power supply 2115 drives the control unit 2111. For this purpose, the control unit 2111 is connected to the control unit 2111, and a rectified DC voltage is supplied to the control unit 2111. The power supply 2115 is connected to the anode terminal 1 of the light emitting diode 231 via a light emitting diode drive driver 2116 described later. When a predetermined condition is satisfied, a DC voltage is applied from the power supply 2115 to the light emitting diode 231. Supplied.

As shown in FIG. 5, the power source 2115 includes N voltage doubler rectifier circuits each configured by using a diode and a capacitor in order to double the input AC voltage and rectify and output the DC voltage. N is a positive number) connected N double voltage rectifier circuit 2115a, resistor element R1 having one end connected to output terminal 2115b of N voltage doubler rectifier circuit 2115a, and capacitor Ca connected to resistor element R1. .

Since the N voltage doubler rectifier circuit 2115a is a circuit in which N voltage doubler rectifier circuits are connected as described above, the N voltage doubler rectifier circuit 2150a rectifies the input AC voltage into a DC voltage and outputs it. Therefore, the N-fold voltage rectifier circuit 2115a rectifies the AC voltage during reception obtained from the AC reception signal 60 received by the transmission / reception antenna 221 approximately N times, and rectifies the DC voltage to output it. The number N of connection stages of the voltage doubler rectifier circuit is determined so that the output voltage is equal to or higher than the driving voltage of the light emitting diode 231 described later. In this way, the N-fold voltage rectifier circuit 2115a boosts the reception AC voltage so that the reception AC voltage obtained from the AC reception signal 60 received by the transmission / reception antenna 221 is equal to or higher than the driving voltage of the light emitting diode 231. At the same time, it is rectified to DC voltage.

A part of the DC voltage rectified by the N-fold voltage rectifier circuit 2115a is charged to the capacitor Ca via the resistance element R1. Further, the resistance element R1 suppresses the charging voltage charged in the capacitor Ca from being discharged to the transmitting / receiving antenna 221 side. Further, the resistance element R1 transmits the DC voltage rectified by the N-fold voltage rectifier circuit 2115a to the capacitor Ca so that the charging voltage charged in the capacitor Ca becomes equal to or higher than the driving voltage of the light emitting diode 231. Note that the N-fold voltage rectifier circuit 2115a gradually boosts and rectifies the AC voltage during reception, so that the capacitor Ca is gradually charged.

Returning to the description of FIG. 4, the light emitting diode driver 2116 is a field effect transistor, the gate terminal is connected to the control unit 2111, the source terminal is connected to the power source 2115, and the drain terminal is the light emitting diode 231. The anode terminal 1 is connected. The light emitting diode driver 2116 serves as a switching element. When a high level signal is input from the control unit 2111 to the gate terminal, the source-drain is electrically connected, and the low level signal is output from the control unit 2111. When the signal is input to the gate terminal, the source and drain are disconnected. In the present embodiment, a low level signal (0 V) is input from the control unit 2111 during normal times. That is, during normal times, the light emitting diode driver 2116 is in a cut-off state.

The control unit 2111 executes a wireless tag control process described later. In addition, the control unit 2111 monitors the voltage value of the power supply supplied from the power supply 2115. The control unit 2111 includes a CPU 2111a, a ROM 2111b, and a RAM 2111c. The ROM 2111b stores a program for executing the RFID tag control process, and the CPU 2111a executes the RFID tag control process according to the program stored in the ROM 2111b. Further, the RAM 2111c has a role of temporarily storing information in the process of executing the wireless tag control process.

As described above, the light emitting diode 231 is an organic EL, the anode terminal 1 is connected to the drain terminal of the light emitting diode drive driver 2116, and the cathode terminal 2 is connected to the ground. The light emitting diode 231 emits light when a voltage higher than a predetermined driving voltage is applied between the anode and the cathode.

As shown in FIG. 6, the light emitting diode 231 includes an anode terminal 1, a cathode terminal 2, an anode 231a, a cathode 231b, a light emitting layer 231c, an insulating layer 231d, and a cathode supporting laminate film 231e. In order to provide the light emitting diode 231 configured as described above on the substrate 241 which is a PET film, a metal layer such as Cu is formed as the anode terminal 1 by etching or screen printing. Similarly, a metal layer such as Cu is formed as the cathode terminal 2 by etching or screen printing. Next, an ITO (Indium Tin Oxide) layer is formed as the anode 231a by screen printing or ink jet printing. Next, as the light emitting layer 231c, PPV, PF, PVK, or the like is formed by screen printing or ink jet printing. Next, the insulating layer 231d is formed by screen printing or ink jet printing. The cathode 231b is formed in advance on the cathode support laminate film 231e by vapor deposition. Finally, the cathode support laminate film 231e on which the cathode 231b is formed is pressed by heat. Note that Al is used for the cathode 231b. The cathode support laminate film 231e is made of plastic such as PET. Thus, the light emitting diode 231 can be formed at low cost by using the printing technique.

Note that the chip 211 and the transmission / reception antenna 221 are installed on the substrate 241 after the light emitting diode 231 is formed on the substrate 241.

Next, the reader / writer control process executed by the control unit 12 of the reader / writer 10 will be described based on the flowchart of FIG. This reader / writer control process is started when the on / off switch of the power supply 14 is turned on, and thereafter is executed at regular intervals.

First, in step S11, it is determined whether or not the user has operated the input switch of the input unit 11 to input a search ID code. If the search ID code is input (S11: YES), the process proceeds to step S12. If the search ID code is not input (S11: NO), the process of this flowchart ends. .

In step S12, it is determined whether or not the transmission switch of the input unit 11 has been operated. This is determined by whether or not a transmission instruction signal is input from the input unit 11. If the transmission switch of the input unit 11 is operated (S12: YES), the process proceeds to step S13, and if the transmission switch of the input unit 11 is not operated (S12). : NO), this step is executed again.

In step S13, the search ID code is transmitted to the outside. Specifically, the search ID code is input to the modulation unit 15. The modulation unit 15 modulates the input search ID code into an AC transmission signal 50 that is a signal that can be transmitted to the outside, and transmits the AC transmission signal 50 to the outside from the transmission / reception antenna 17 (S13).

In the subsequent step S14, it is determined whether or not a reply signal from the wireless tags 201 to 209 has been received. Specifically, when the wireless tags 201 to 209 transmit a reply signal to the outside, the transmission / reception antenna 17 receives the reply signal. Then, the reply signal received by the transmission / reception antenna 17 is input to the demodulation unit 16. The reply signal input to the demodulator 16 is demodulated, and the demodulated reply signal is input to the controller 12. Therefore, the control unit 12 determines whether or not the reply signals from the wireless tags 201 to 209 are received depending on whether or not a reply signal is input from the demodulation unit 16 (S14). If the reply signals from the wireless tags 201 to 209 are received (S14: YES), the process proceeds to step S15, and if the reply signals from the wireless tags 201 to 209 are not received (S14: NO). ), The reader / writer control process of this flowchart ends. In this case, even if the wireless tags 201 to 209 have not received or received the AC transmission signal 50 transmitted in step S13, there may be a case where the collation is not permitted in the collation determination. If the wireless tags 201 to 209 have not received the AC transmission signal 50, it is necessary to bring the reader / writer 10 closer to the wireless tags 201 to 209 and transmit the AC transmission signal 50. Further, in the collation permission / inhibition determination, when the collation is rejected, it is necessary to transmit the AC transmission signal 50 toward the book to which another wireless tag is attached.

In step S15, the display unit 13 displays that the search ID code included in the AC transmission signal 50 transmitted in step S13 matches the stored ID code stored in the wireless tags 201 to 209. Informed. For example, a message “verification is possible” is displayed. Thereafter, the reader / writer control process of this flowchart ends. On the other hand, when the reply signals from the wireless tags 201 to 209 are not received (No at Step S14), the notification is not made.

Subsequently, the wireless tag control process executed by the CPU 2111a included in the control unit 2111 of the wireless tag 201 will be described with reference to the flowchart of FIG. This flowchart is started when the AC reception signal 60 is received.

First, in step S21, a search ID code is received. Specifically, the AC reception signal 60 received by the transmission / reception antenna 221 is input to the demodulation unit 2113. The demodulator 2113 demodulates the input AC reception signal 60 into a search ID code, and inputs the search ID code to the CPU 2111a.

In the subsequent step S22, the input search ID code is collated with the storage ID code stored in the storage unit 2112. In subsequent step S23, it is determined whether or not the search ID code and the stored ID code match as a result of the collation in step S22. If the search ID code matches the storage ID code (S23: YES), the process proceeds to step S24. If the search ID code does not match the storage ID code (S23: NO) ), The wireless tag control process ends. In this case, since the electric charge charged in the capacitor Ca of the power supply 2115 is not discharged to the light emitting diode 231, the light emitting diode 231 does not emit light. In the present embodiment, it is determined whether or not the search ID code and the storage ID code match in step S23, but whether or not the search ID code and the storage ID code satisfy a predetermined relationship. May be determined.

In step S24, it is determined whether or not the capacitor Ca constituting the power source 2115 is charged to a driving voltage necessary for causing the light emitting diode 231 to emit light. This is determined based on the value of the voltage input from the power source 2115 (the charging voltage charged in the capacitor Ca). If the capacitor Ca is charged until the drive voltage is reached (S24: YES), the process proceeds to step 25, and if the capacitor Ca is not charged until the drive voltage is reached, again, The determination process of this step is executed.

In step S25, a discharge instruction signal which is a high-level signal is input to the gate terminal of the light emitting diode driver 2116 so that the light emitting diode driver 2116 becomes conductive. As a result, the source-drain of the light-emitting diode driver 2116 conducts, and the charging voltage charged in the capacitor Ca of the power source 2115 is applied between the anode and cathode of the light-emitting diode 231. The light emitting diode 231 emits light. Accordingly, when the user visually recognizes that the light emitting diode 231 emits light, the user can find the book 101 being searched for in the book box 20.

In the subsequent step S26, a reply signal indicating that the search ID code matches the stored ID code is transmitted to the outside. Specifically, the return signal is input to modulation section 2114. Modulation section 2114 modulates the input reply signal into a format that can be transmitted to the outside, and transmits the modulated reply signal from transmission / reception antenna 221 to the outside. After that, the reader / writer 10 that has received this reply signal displays, for example, “verification is now possible” on the display unit 13 as described above. And this flowchart is complete | finished.

As described above, in the wireless tag 201 of the present embodiment, the AC transmission signal 50 including the search ID code transmitted from the reader / writer 10 is received as the AC reception signal 60. At this time, since the power supply 2115 has the N-fold voltage rectifier circuit 2115a, the AC voltage at the time of reception obtained from the AC received signal 60 is approximately N times and is rectified to a direct current and output. The number N of connection stages of the voltage doubler rectifier circuit is determined so that the output voltage is equal to or higher than the driving voltage of the light emitting diode 231. Therefore, even if the AC reception signal 60 is a weak signal, it is boosted and rectified by the power source 2115, so that the light emitting diode 231 emits light when the search ID code matches the stored ID code. Can do. Accordingly, even if the distance between the reader / writer 10 and the wireless tag 201 is increased, the light emitting diode 231 provided in the wireless tag 201 can emit light, so that the usability of the wireless tag 201 can be improved. Alternatively, even if the AC transmission signal 50 transmitted from the reader / writer 10 is a weak signal, the light emitting diode 231 can emit light, so that power consumption can be suppressed.

Further, since the light emitting diode 231 is formed on the substrate 241 by printing, the cost can be reduced.

In addition, the CPU 2111a of the control unit 2111 monitors the value of the charging voltage charged in the capacitor Ca of the power supply 2115, and the light emitting diode after determining that the search ID code matches the stored ID code A discharge instruction signal is input to the gate terminal of the light emitting diode driver 2116 at the timing when the driving voltage 231 is reached. Thereby, the light emitting diode 231 can emit light quickly and reliably.

In the power source 2115, a resistance element R1 is connected between the N-fold voltage rectifier circuit 2115a and the capacitor Ca. Thereby, it is possible to suppress the charging voltage charged in the capacitor Ca from being discharged to the transmitting / receiving antenna 221 side with a simple configuration. Furthermore, the DC voltage rectified by the N-fold voltage rectifier circuit 2115a can be efficiently transmitted to the capacitor Ca so that the charging voltage charged in the capacitor Ca becomes equal to or higher than the driving voltage of the light emitting diode 231.

Further, as a boost rectifier circuit, an N double voltage rectifier in which one or a plurality of voltage double rectifier circuits that rectify an input AC voltage constituted by using a diode and a capacitor and rectify it to a DC voltage and output it is connected. Since the circuit 2115a is employed, the AC voltage at the time of reception can be boosted and rectified to a DC voltage so as to be a voltage desired by the user with a simple configuration.

Note that the wireless tags 202 to 209 other than the wireless tag 201 have the same configuration as the wireless tag 201 except for the stored ID code, and therefore, the same effect as the wireless tag 201 can be obtained.

(Second Embodiment)
Next, a second embodiment of the wireless tag according to the present disclosure will be described. In the method of using the wireless tag of this embodiment, wireless tags having different storage ID codes are attached to a plurality of books, as in the first embodiment. Then, in order to find a desired book, the user causes the wireless tag attached to the desired book to emit light using a reader / writer.

FIG. 9 is a block diagram showing an electrical configuration of the wireless tag 251 of the present embodiment. In addition, the same code | symbol is attached | subjected to what has the same function as the said 1st Embodiment. As shown in FIG. 9, the wireless tag 251 of the present embodiment has the same configuration as the wireless tag 201 to 209 of the first embodiment except for the control unit 2117. The configuration of the reader / writer 10 is the same between the first embodiment and the second embodiment. Note that the wireless tag 251 is attached to the book 151. Hereinafter, the wireless tag 251 of the present embodiment will be described focusing on differences from the first embodiment.

The control unit 2117 executes the wireless tag control process similarly to the first embodiment, but the content is different from that of the first embodiment. From this relationship, in the present embodiment, the control unit 2117 does not monitor the voltage value supplied from the power source 2115. The wireless tag control process in the present embodiment will be described later using a flowchart. The control unit 2117 includes a CPU 2117a, a ROM 2117b, and a RAM 2117c. The ROM 2117b stores a program for executing the RFID tag control process, and the CPU 2117a executes the RFID tag control process according to the program stored in the ROM 2117b. In addition, the RAM 2117c plays a role of temporarily storing information in the process of executing the wireless tag control process.

Note that the charging voltage charged in the capacitor Ca of the power source 2115 is the drive voltage of the light emitting diode 231 based on the time when the transmission / reception antenna 221 receives the AC reception signal 60 from the capacitance of the capacitor Ca and the value of the resistance element R1. The expected charging time expected to become can be determined in advance. The estimated charging time is stored in the ROM 2117b, and the estimated charging time is referred to in the process of executing the wireless tag control process.

Subsequently, the wireless tag control process executed by the CPU 2117a will be described with reference to FIG. This flowchart is started when the AC reception signal 60 is received. In addition, the same code | symbol is attached | subjected about the process same as 1st Embodiment.

First, in step S21, a search ID code is received. In subsequent step S31, time measurement is started in order to measure the expected charging time. In the subsequent step S <b> 22, the input search ID code is collated with the storage ID code stored in the storage unit 2112. In the subsequent step S23, it is determined whether or not the search ID code and the stored ID code match as a result of the collation. If the search ID code matches the storage ID code (S23: YES), the process proceeds to step S32. If the search ID code does not match the storage ID code (S23: NO) ), The wireless tag control process ends. In this case, the light emitting diode 231 does not emit light.

In Step S32, it is determined whether or not the measurement time started in Step S31 has passed the expected charging time. If the expected charging time has elapsed (S32: YES), the process proceeds to step S25. If the expected charging time has not yet elapsed (S32: NO), this step is executed again.

In step S25, a discharge instruction signal which is a high-level signal is input to the gate terminal of the light emitting diode driver 2116 so that the light emitting diode driver 2116 becomes conductive. As a result, the source-drain of the light-emitting diode driver 2116 conducts, and the charging voltage charged in the capacitor Ca of the power source 2115 is applied between the anode and cathode of the light-emitting diode 231. This charging voltage is approximately equal to the driving voltage of the light emitting diode 231. Therefore, the light emitting diode 231 emits light. Thus, when the user visually recognizes that the light emitting diode 231 emits light, the user can find the book 151 searched by himself / herself from the book box.

In the subsequent step S26, a reply signal indicating that the search ID code matches the stored ID code is transmitted to the outside. Then, the wireless tag control process of this flowchart ends.

As described above, in the wireless tag 251 of the present embodiment, the expected charging time is stored in the ROM 2117b, and the expected charging time is referred to in the process of executing the wireless tag control process. Specifically, when the transmission / reception antenna 221 receives an AC reception signal and the search ID code included in the AC reception signal matches the stored ID code, the CPU 2117a of the control unit 2117 receives the AC reception. The discharge instruction signal is input to the gate terminal of the light emitting diode driver 2116 at the timing when the expected charging time has elapsed with respect to the time when the signal is received. Thus, the light emitting diode 231 may be caused to emit light at the timing of the expected charging time without monitoring the value of the charging voltage charged in the capacitor Ca. Even if it does in this way, the effect similar to 1st Embodiment can be acquired.

(Third embodiment)
Next, a third embodiment of the wireless tag according to the present disclosure will be described. FIG. 11 is a block diagram showing an electrical configuration of the wireless tag 261 of the present embodiment. In addition, what has the same function as 1st, 2nd embodiment attaches | subjects the same code | symbol. As shown in FIG. 11, the wireless tag 261 differs from the wireless tags 201 to 209, 251 of the first and second embodiments only in the power source 2118, and the other configurations are the same. Further, the method of using the wireless tag 261 and the operation of the wireless tag 261 are the same as those in the first and second embodiments. Further, the reader / writer 10 is the same as that in the first and second embodiments. Note that the wireless tag 261 is attached to the book 161. Hereinafter, the wireless tag 261 of the present embodiment will be described focusing on differences from the first and second embodiments.

FIG. 12 is a block diagram showing an electrical configuration of the power source 2118 of the wireless tag 261 of the present embodiment. In addition, what has the same function as 1st, 2nd embodiment attaches | subjects the same code | symbol. As shown in FIG. 12, the power source 2118 includes an N-fold voltage rectifier circuit 2115a, a bipolar transistor Tr, a Zener diode Dz, a resistance element R2, and a capacitor Ca. Thus, the N-fold voltage rectifier circuit 2115a and the capacitor Ca are the same as those in the first and second embodiments. That is, the power supply 2118 gradually boosts and rectifies the reception AC voltage obtained from the AC reception signal received by the transmission / reception antenna 221 by the N-fold voltage rectifier circuit 2115a, and outputs a part of the output voltage. Charge with capacitor Ca. Here, in the first and second embodiments, the resistor element R1 is connected between the N-fold voltage rectifier circuit 2115a and the capacitor Ca. In this embodiment, instead of the resistor element R1, the bipolar transistor Tr1 is connected. A circuit composed of a Zener diode Dz through which a current flows when a predetermined Zener voltage is applied in the reverse direction and a resistance element R2 is connected.

The bipolar transistor Tr is a PNP transistor, the emitter terminal of which is connected to the output terminal 2115b of the N-fold voltage rectifier circuit 2115a, the collector terminal is connected to the capacitor Ca, and the base terminal is a Zener diode Dz. Is connected to the cathode terminal. The anode terminal of the Zener diode Dz is connected to the ground via the resistance element R2.

In the power supply 2118 having such a configuration, when the transmission / reception antenna 221 receives the AC reception signal 60, a reception AC voltage obtained from the AC reception signal 60 is input to the N-fold voltage rectifier circuit 2115a, and the reception AC voltage is The pressure is gradually increased and rectified. As the potential at the output terminal 2115b of the N-fold voltage rectifier circuit 2115a is gradually increased, the potential at the base terminal of the bipolar transistor Tr is also gradually increased. However, the difference (voltage applied to the Zener diode Dz) between the potential of the base terminal of the bipolar transistor Tr (the potential of the cathode terminal of the Zener diode Dz) and the potential of the anode terminal of the Zener diode Dz (ground) is the Zener voltage. Until it reaches, no current flows through the Zener diode Dz. That is, since no current flows through the base terminal of the bipolar transistor Tr, no current flows between the emitter and collector of the bipolar transistor Tr. Therefore, the capacitor Ca is not charged.

Thereafter, when the potential of the output terminal 2115b of the N-fold voltage rectifier circuit 2115a is gradually increased and the voltage applied to the Zener diode Dz reaches the Zener voltage, a current flows through the Zener diode Dz. That is, since a current flows through the base terminal of the bipolar transistor Tr, a current flows between the emitter and collector of the bipolar transistor Tr. Along with this, voltage starts to be charged in the capacitor Ca. As the potential of the output terminal 2115b of the N-fold voltage rectifier circuit 2115a further increases and the voltage applied to the Zener diode Dz becomes larger than the Zener voltage, more current flows through the Zener diode Dz. That is, a large amount of current flows through the base terminal of the bipolar transistor Tr. As a result, a current suddenly flows between the emitter and collector of the bipolar transistor Tr due to the current amplification effect of the transistor. Accordingly, the voltage is rapidly charged in the capacitor Ca.

FIG. 13 is a diagram for explaining the time change of the charging voltage charged in the capacitor Ca. A curve 3 shows a time change of the voltage applied to the Zener diode Dz. Curve 4 shows the time change of the charging voltage charged to the capacitor Ca when the resistor element R1 is connected between the N-fold voltage rectifier circuit 2115a and the capacitor Ca as in the first and second embodiments. Show. Curve 5 shows a capacitor when a circuit composed of a bipolar transistor Tr, a Zener diode Dz, and a resistor element R2 is connected between the N-fold voltage rectifier circuit 2115a and the capacitor Ca instead of the resistor element R1. The time change of the charging voltage charged to Ca is shown. As shown in FIG. 13, the curve 4 has a substantially proportional relationship between time and the charging voltage charged in the capacitor Ca. On the other hand, the curve 5 is substantially zero until the curve 3 reaches the Zener voltage, and after the time when the curve 3 exceeds the Zener voltage, the charging voltage charged in the capacitor Ca changes rapidly. . Then, the curve 5 reaches the driving voltage of the light emitting diode 231 at a time earlier than the curve 4. That is, by using the bipolar transistor Tr and the Zener diode Dz, the capacitor Ca can be charged with the drive voltage of the light emitting diode 231 earlier than when the resistor element R1 is used.

Note that the circuit constituted by the bipolar transistor Tr, the Zener diode Dz, and the resistance element R2 transmits a part of the voltage boosted and rectified by the N-fold voltage rectifier circuit 2115a to the capacitor Ca. Further, since the bipolar transistor Tr has very little current flowing from the collector side to the emitter side, the charging voltage charged in the capacitor Ca is suppressed from being discharged to the transmitting / receiving antenna 221 side.

As described above, the wireless tag according to the present embodiment employs a circuit including the bipolar transistor Tr, the Zener diode Dz, and the resistance element R2 as the transmission circuit. Thereby, the capacitor Ca can be charged with the drive voltage of the light emitting diode 231 earlier than when the resistance element R1 is employed in the transmission circuit.

(Fourth embodiment)
In the first to third embodiments, the wireless tags 201 to 209, 251 and 261 are attached to the books 101 to 109, 151 and 161, and the user uses the reader / writer 10 to select the desired books 101 to 109, The wireless tags 201 to 209, 251 and 261 are used for searching 151 and 161, but in this embodiment, the wireless tags are used for the purpose of grasping the position, not for the purpose of searching.

FIG. 14 is a diagram for explaining a wireless tag system including the wireless tag 271, the reader / writer 70, and the server 80 according to the present embodiment. As shown in FIG. 14, the reader / writer 70 is installed at a plurality of points. Each reader / writer 70 is connected to the server 80 by wire. On the other hand, the wireless tag 271 is possessed by the user. The configuration of the reader / writer 70 is the same as that of the reader / writer 10, but the processing executed by a control unit (not shown) is different from the processing executed by the control unit 12. The configuration of the wireless tag 271 is the same as that of the wireless tags 201 to 209, but the processing executed by a control unit (not shown) is different from the processing executed by the control unit 2111. Therefore, the description of the configuration of the reader / writer 70 and the configuration of the wireless tag 271 is omitted, and the processing executed by the reader / writer 70, the processing executed by the wireless tag 271 and the processing executed by the server 80 are simply described. Explained.

Each reader / writer 70 periodically transmits an AC transmission signal 51 for calling the wireless tag 271 to the outside. On the other hand, when the wireless tag 271 is near the reader / writer 70, the wireless tag 271 receives the AC transmission signal 51 as the AC reception signal 61, and then transmits the storage ID code to the reader / writer 70. Then, the reader / writer 70 receives the stored ID code and transmits it to the server 80. The server 80 stores the storage ID code transmitted from the reader / writer 70 in association with information (name, address, etc.) regarding the location where the reader / writer 70 is installed and the current time. Further, the server 80 stores information (name, age, address, etc.) related to the user who owns the wireless tag 271 in association with the storage ID code stored in the wireless tag 271. FIG. 14 shows a state where there is a user who has a wireless tag 271 at point A.

As a result, the server 80 can grasp which person is where and when. At this time, when the stored ID code is read by the reader / writer 70, the wireless tag 271 causes the light emitting diode 231 provided therein to emit light. Thereby, the user who possesses the wireless tag 271 can grasp that the stored ID code has been read by the reader / writer 70.

Note that the present invention is not limited to the above embodiment, and can be implemented in various forms based on the gist of the present invention. For example, in the first to fourth embodiments, the charging voltage is discharged at the timing when the charging voltage reaches the driving voltage of the light emitting diode 231 by monitoring the value of the charging voltage or measuring the time. The light emitting diode 231 emits light. However, as long as the charging voltage is equal to or higher than the driving voltage of the light emitting diode 231, the charging voltage may be discharged at any timing to cause the light emitting diode 231 to emit light. If the value of the charging voltage is large, the light emitting diode 231 can be made to emit light for such a long time, so that the user can easily understand that the light emitting diode 231 emits light.

In the first to fourth embodiments, the N voltage doubler rectifier circuit 2115a is used as the step-up rectifier circuit, but a switching regulator may be used instead of the N voltage doubler rectifier circuit 2115a.

As described above, according to the wireless tag of the present disclosure, when an AC reception signal is received, a charging voltage equal to or higher than a predetermined drive voltage is applied to the light emitting diode, so the AC reception signal is a weak signal. However, the light emitting diode can emit light. That is, even when the distance between the reader / writer and the wireless tag is increased, the light emitting diode provided in the wireless tag can be caused to emit light, so that the usability of the wireless tag can be improved. Alternatively, even if the AC transmission signal transmitted from the reader / writer is a weak signal, the light emitting diode can be caused to emit light, and thus power consumption can be suppressed.

Also, since the AC transmission signal includes a search ID code indicating the ID code of the wireless tag that the user wants to search, the search ID code included in the AC reception signal received by the receiving antenna and stored in the ID code storage means It is determined whether or not the stored ID code has a predetermined relationship. As a result, when the verification is rejected, the discharging of the charging voltage is stopped.

In addition, the boost rectifier circuit is configured by using a diode and a capacitor, and is a circuit in which one or a plurality of voltage doubler rectifier circuits that rectify an input AC voltage and rectify it to a DC voltage for output. Therefore, the AC voltage during reception can be boosted and rectified to a DC voltage so as to be a voltage desired by the user with a simple configuration.

Also, since the charging voltage is discharged at a predetermined timing after the charging voltage becomes equal to or higher than the predetermined driving voltage, the light emission timing of the light emitting diode can be controlled, so that the usability of the wireless tag can be improved.

Further, since the value of the charging voltage is monitored and the charging voltage is discharged at the timing when the value of the charging voltage reaches a predetermined driving voltage, the light emitting diode can be caused to emit light quickly and reliably.

The expected charging time that the charging voltage is expected to become the predetermined driving voltage is determined in advance with reference to the time when the receiving antenna receives the AC reception signal. Since the charging voltage discharging means discharges the charging voltage at the timing of the expected charging time, the light emitting diode can be made to emit light quickly.

In addition, when the transmission circuit is configured by a resistance element, it is possible to charge the charging circuit with a simple configuration with less load due to the boosted rectified voltage.

Further, when the boosted rectified voltage transmission circuit is configured by a circuit including a transistor and a Zener diode, the transistor does not conduct until the boosted rectified voltage exceeds the Zener voltage, but the boosted rectified voltage exceeds the Zener voltage. Sometimes, the transistor becomes conductive and the boosted rectified voltage is transmitted to the charging circuit. At this time, due to the current amplifying action of the transistor, the charging circuit is charged with a voltage equal to or higher than the predetermined drive voltage earlier than when the resistance element is used as the transmission circuit.

Claims

A wireless tag that performs wireless communication with a reader / writer that transmits an AC transmission signal to the outside,
A receiving antenna that receives the AC transmission signal transmitted from the reader / writer as an AC reception signal;
A light emitting diode that emits light when a predetermined drive voltage larger than the reception AC voltage indicating the AC voltage obtained from the AC reception signal is applied in the forward direction;
The reception AC voltage is boosted and rectified to a DC voltage so that the reception AC voltage obtained from the AC reception signal received by the reception antenna is equal to or higher than the predetermined drive voltage. A boost rectifier circuit;
A charging circuit in which at least a part of the boosted rectified voltage boosted by the boost rectifier circuit and rectified to a DC voltage is charged;
Connected between the charging circuit and the receiving antenna, the boosted rectified voltage is suppressed from being discharged to the receiving antenna side, and the charging voltage charged in the charging circuit becomes equal to or higher than the predetermined driving voltage. A transmission circuit for transmitting the boosted rectified voltage to the charging circuit,
A wireless tag comprising: charging voltage discharging means for discharging the charging voltage so that a charging voltage charged in the charging circuit is applied in a forward direction of the light emitting diode.
The AC transmission signal includes a search ID code indicating an ID code of a wireless tag that the user wants to search,
The wireless tag is
ID code storage means for storing a storage ID code;
Checking whether or not to check whether or not the search ID code included in the AC reception signal received by the receiving antenna and the stored ID code stored in the ID code storage means satisfy a predetermined relationship. Determination means,
2. The wireless tag according to claim 1, wherein the charging voltage discharging unit stops discharging the charging voltage when it is determined that the verification is impossible by the verification availability determination unit.
The step-up rectifier circuit is a circuit in which a single or a plurality of voltage doubler rectifier circuits configured by using a diode and a capacitor, which approximately doubles an input AC voltage and rectifies and outputs a DC voltage, are connected. The wireless tag according to claim 1 or 2, characterized in that:
The boosted rectified voltage is gradually charged into the charging circuit,
4. The charging voltage discharging unit according to claim 1, wherein the charging voltage discharging unit discharges the charging voltage at a predetermined timing after the charging voltage becomes equal to or higher than the predetermined driving voltage. Wireless tag.
The wireless charging according to claim 4, wherein the charging voltage discharging means monitors the value of the charging voltage and discharges the charging voltage at a timing when the value of the charging voltage reaches the predetermined driving voltage. tag.
With reference to the time when the receiving antenna receives the AC reception signal, an expected charging time that the charging voltage is expected to become the predetermined driving voltage is predetermined,
The wireless tag according to claim 4, wherein the charging voltage discharging unit discharges the charging voltage at the timing of the expected charging time.
The wireless tag according to any one of claims 1 to 6, wherein the transmission circuit is a resistance element.
The boost rectifier circuit gradually boosts the reception AC voltage,
The transmission circuit is connected between a Zener diode that conducts when a voltage equal to or higher than a predetermined Zener voltage is applied to both ends, and is connected between the boost rectifier circuit and the charging circuit, and controls conduction and interruption of current, and also an input current And a transistor for amplifying
The Zener diode and the transistor are connected so that the transistor becomes conductive when the voltage gradually boosted by the boost rectifier circuit becomes equal to or higher than the Zener voltage. The wireless tag according to any one of 6.