JP2014006591A - Load fluctuation type wireless tag reader and wireless tag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless tag reader supporting wireless power feed, and a wireless tag.SOLUTION: A wireless tag reader 1 starts wireless power feed to a wireless tag 2, and subsequently superimposes a reader ID or a tag ID of a reading object on high-frequency power of the wireless power feed and notifies the wireless tag 2 of ID information. The wireless tag 2 determines whether or not to notify the wireless tag reader 1 of an own tag ID according to the ID information notified from the wireless tag reader 1, and when determining to notify the wireless tag reader 1, controls fluctuation of a load value to power being wirelessly fed and notifies the wireless tag reader 1 of the own tag ID.

Description

  The present invention relates to a wireless tag reader and a wireless tag constituting a wireless tag system.

  2. Description of the Related Art In recent years, wireless tags (RFID: Radio Frequency IDentification) storing ID information and wireless tag readers that read ID information from wireless tags in a contactless manner have been applied in the management of goods, the management of physical distribution, and the like. There are two types of wireless tags: an active type that transmits a radio wave including ID information itself, and a passive type that operates with radio wave energy emitted from a radio tag reader and modulates a reflected wave of the radio wave with ID information. The active type transmits a radio wave by itself and has a relatively wide range in which an ID can be notified (for example, several meters). However, since it operates on a battery, there is a restriction that periodic battery replacement is necessary. On the other hand, since the passive type operates with radio wave energy emitted by the wireless tag reader, a battery is unnecessary, but there is a restriction that a range in which ID can be notified is narrow (for example, several centimeters).

  As a technique for improving this, it is conceivable to apply a so-called wireless power feeding technology for supplying electric power wirelessly via electromagnetic waves, ultrasonic waves, a resonating magnetic field or electric field, laser light, etc. to a wireless tag reader and a wireless tag ( For example, see Patent Document 1).

  However, the technique described in Patent Document 1 is a technique related to an inductive power transfer system. In order to apply this technique to a wireless tag reader and a wireless tag, it is necessary to efficiently read ID information from an unspecified number of wireless tags. Insufficient consideration.

JP 2011-30422 A

  Therefore, an object of the present invention is to provide a wireless tag reader and a wireless tag compatible with wireless power feeding, in which a readable range can be set relatively freely and ID information can be efficiently read from an unspecified number of wireless tags. There is to do.

  In order to solve the above problems, a wireless tag reader according to the present invention is a wireless tag reader that supplies power to a predetermined wireless tag in a non-contact manner and receives tag ID information notified by the wireless tag, Wireless power supply means for generating a magnetic field and supplying electric power to the wireless tag, current value fluctuation detection means for detecting current value fluctuation of current flowing through a predetermined part of the wireless power supply means, and the current value fluctuation detection means Tag ID information extracting means for extracting tag ID information included in the detected current value fluctuation, and the current value fluctuation detection when the wireless power feeding means supplies power to the wireless tag. When the means detects the current value fluctuation caused by the load fluctuation on the wireless tag side, the tag ID information extracting means extracts the tag ID information included in the current value fluctuation. It is characterized in.

  The wireless tag according to the present invention is a wireless tag that receives power from a predetermined wireless tag reader in a non-contact manner by wireless power feeding and notifies tag ID information stored in the wireless tag, and is generated by the wireless tag reader. A wireless power receiving means for receiving electric power in a non-contact manner by a fluctuating electric field or magnetic field, an ID information storage means for storing tag ID information, and a predetermined load value for applying the electric power received by the wireless power receiving means. A load changing means for changing the load changing means, and an ID information notifying means for controlling the load changing means to notify the tag ID information to the wireless tag reader, and when the wireless power receiving means receives power, The ID information notifying unit controls the load changing unit to change the load value according to the tag ID information.

  According to the present invention, the readable range can be set relatively freely as in the conventional active type, and ID information can be efficiently obtained from an unspecified number of wireless tags that do not require battery replacement as in the conventional passive type. It is possible to provide a wireless tag reader and a wireless tag that can be read and are compatible with wireless power feeding.

Wireless tag reader and wireless tag overall configuration diagram according to the present invention Sequence diagram of wireless tag reader and wireless tag according to the present invention Block diagram of the internal structure of the wireless tag reader according to the present invention Internal block configuration diagram of wireless tag according to the present invention

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a load variation type wireless tag system (hereinafter, also abbreviated as this system) using a wireless tag reader and a wireless tag according to the present invention.

  With reference to FIG. 1, the configuration and functional outline of this system will be described. Reference numeral 1 denotes a wireless tag reader according to the present invention, and reference numeral 2 denotes a wireless tag according to the present invention that communicates with the wireless tag reader 1. Note that the upper limit of the number N of wireless tags (arbitrary integer) depends on the number of digits of ID information (hereinafter also abbreviated as ID) stored in the wireless tag 2.

  The wireless tag reader 1 operates from a commercial power source or a battery, and supplies power to the nearby wireless tag 2 by wireless power feeding periodically or irregularly. At that time, ID information of the wireless tag reader 1 itself or ID information to be read may be superimposed on the power.

  The wireless tag 2 operates by receiving power from wireless power supply from the wireless tag reader 1 and notifies the wireless tag reader 1 of tag ID information stored in the wireless tag 2. Depending on the conditions, tag ID information may not be notified to the wireless tag reader 1 (described later).

  FIG. 2 is a sequence diagram of the wireless tag reader 1 and the wireless tag 2. Hereinafter, the flow of power and signals in this system will be described with reference to FIG.

  When the wireless tag reader 1 is activated by periodic automatic activation or non-periodic manual activation by a predetermined operation (S211), the wireless tag reader 1 starts wireless power feeding by high frequency power of magnetic field resonance (S212). Then, the wireless tag 2 receives power from the wireless tag reader 1 (S221), and the wireless tag 2 is activated by the power (S222).

  The ID information of the reader ID of the wireless tag reader 1 or the tag ID to be read may be superimposed on the high frequency power of wireless power feeding from the wireless tag reader 1 (S230). The wireless tag 2 extracts this ID information and determines whether or not to notify the tag ID (S223). In this determination, for example, it is determined whether or not the wireless tag reader 1 that has been wirelessly powered is a registered wireless tag reader, or whether or not the tag ID of the wireless tag is the ID information that the wireless tag reader 1 requires. .

  Note that the condition for determining whether or not to notify the tag ID is registered in advance in a notification condition registration unit 29 shown in FIG. Specifically, the ID information notified in S230 is collated with the ID information registered in the notification condition registration unit 29, and it is determined whether or not to notify the own ID information. For example, if the condition is to notify a specific wireless tag reader, the wireless tag reader 1 notifies its reader ID in S230. If the condition is to notify the wireless tag reader that has targeted the wireless tag, the wireless tag reader 1 notifies the tag ID of the target wireless tag 2 in S230.

  If it is determined in S223 that notification is to be made (S223, YES), the wireless tag 2 sets its own tag ID to the wireless tag reader 1 after a different time wait (S224) for each tag ID (for example, several milliseconds to several seconds). (S231). This time wait prevents a collision of a plurality of tag ID information notified by a plurality of wireless tags 2 when there are a plurality of wireless tags 2 in an area where the wireless tag reader 1 is wirelessly powered. For example, the time value (delay time) may be calculated by multiplying the ID value by a predetermined constant.

  When the ID information is not detected or when it is determined that notification should not be made (S223, NO), the wireless tag 2 skips S231 and does not notify the tag ID.

  Although not shown in the figure, it is needless to say that the case where it is determined in S223 that the tag ID is not notified (S223, NO) includes the case where the ID information notification waiting in S230 times out. Further, if the notification condition is not registered in the wireless tag 2, it is only necessary to exit S223 to the YES side and notify the wireless tag reader 1 of its own tag ID regardless of whether or not the ID information is notified in S230 ( S231).

  The wireless tag reader 1 starts the wireless power supply in S212, or notifies the reader ID of the wireless tag reader 1 or the ID information of the tag ID to be read in S230, and then the tag ID notified by the wireless tag 2 in S231. Reception is monitored (S213). When the tag ID is received (S213, YES), the process proceeds to S215, and information related to the tag ID is displayed as a reading result. In S215, when a plurality of tag IDs are received from a plurality of wireless tags 2, information regarding all received tag IDs is displayed.

  If the tag ID is not received (S213, NO) and time-out occurs (S214, YES), the fact that the tag ID has not been detected is displayed as the reading result (S215).

  After S215, the wireless tag reader 1 stops wireless power feeding (S216). Accordingly, the wireless tag 2 also stops wireless power reception (S225).

  Next, the internal block configuration and function of the wireless tag reader 1 will be described. FIG. 3 shows an example of the internal block configuration of the wireless tag reader 1 according to the present invention.

  The reader control unit 10 controls each unit in the wireless tag reader 1. The power supply unit 11 supplies a predetermined voltage to each unit from a commercial power source or a power source such as a battery. The high frequency power supply unit 12 is means for converting electric power from the power supply unit 11 into high frequency power for magnetic field resonance (for example, 13.56 MHz), and is activated / stopped by an instruction from the reader control unit 10. The matching circuit unit 13 is a matching circuit for supplying high frequency power from the high frequency power supply unit 12 by magnetic field resonance.

  The ID information superimposing unit 14 is a unit that superimposes the ID information output from the reader control unit 10 on the high frequency power output from the matching circuit unit 13. For example, the ID information superimposing unit 14 converts the high frequency power from the matching circuit unit 13 into ID information. Modulate (for example, ASK modulation, PSK modulation, PWM modulation, etc.). This modulation may be executed inside the high frequency power supply unit 12. The superimposition of the ID information is a process corresponding to the wireless tag reader 1 side in S230 of FIG.

  The current fluctuation detection unit 15 monitors the current value fluctuation of the high-frequency power flowing into the power feeding device 16, outputs the detected current value fluctuation to the tag ID extraction unit 17, and receives the ID information from the wireless tag 2. This current value fluctuation is caused by the fluctuation of the load value of the load fluctuation unit 24 to which the power received by the wireless tag 2 is wirelessly applied. The wireless tag 2 controls the fluctuation of the load value according to the value of the tag ID. (Details will be described later).

  The power feeding device 16 is a device including a power feeding coil, and emits a fluctuating electromagnetic field generated by high frequency power for magnetic field resonance to the wireless tag 2.

  The tag ID extraction unit 17 receives the tag ID information that is modulated (for example, ASK modulation, PSK modulation, PWM modulation, etc.) by the current value variation input from the current variation detection unit 15, that is, the load value variation of the wireless tag 2. Receive. The reception of the tag ID information is processing corresponding to the wireless tag reader 1 side in S231 in FIG.

The reader ID storage unit 18 stores in advance a reader ID unique to the own wireless tag reader. The display unit 19 displays the tag ID read from the wireless tag 2. If the wireless tag 2 does not exist in the vicinity of the wireless tag reader 1, a message indicating that the wireless tag 2 has not been detected is displayed. The read tag ID may be transmitted not only to display but also to another device or a predetermined destination (not shown).
Next, the internal block configuration and function of the wireless tag 2 will be described. FIG. 4 is an example of an internal block configuration of the wireless tag 2 according to the present invention.

  The tag control unit 20 controls each unit in the wireless tag 2. The power receiving device 21 is a device including a coil that receives power supplied wirelessly from the wireless tag reader 1 and receives a variable electromagnetic field for magnetic field resonance emitted from the wireless tag reader 1. The matching circuit unit 22 is a matching circuit for receiving high-frequency power from the varying electromagnetic field received by the power receiving device 21 by magnetic field resonance.

  The power conversion unit 23 converts the received high frequency power into a predetermined DC voltage, charges the power storage unit 25, and notifies the tag control unit 20 that the wireless tag reader 1 is receiving wireless power feeding.

  The load changing unit 24 is a means for notifying the wireless tag reader 1 of the tag ID, changes the load value at a constant period (for example, 100 KHz) and stores it in the tag ID storage unit 27 according to an instruction from the tag control unit 20. The load value fluctuation is modulated according to the tag ID value (for example, ASK modulation, PSK modulation, PWM modulation, etc.). The means for fluctuating and modulating the load value inserts an element (for example, a field effect transistor) capable of electronically controlling the resistance value in series or in parallel with the voltage input from the power conversion unit 23, and the resistance value. May be controlled so as to vary according to the value of the tag ID. Then, the fluctuation of the input current from the power receiving device 21 occurs according to the resistance value fluctuation, and the current fluctuation is transmitted as the fluctuation of the current value flowing through the power feeding device 16 of the wireless tag reader 1 that is the power feeding source of the wireless power feeding. The notification of the tag ID information due to the load fluctuation is a process corresponding to the wireless tag 2 side in S231 of FIG.

  The power storage unit 25 stores the DC voltage supplied from the power conversion unit 23 and supplies it to each unit. A capacitor, an electric double layer capacitor, a lithium ion secondary battery, or the like can be applied as a device for storing electricity. Note that the power storage unit 25 may be omitted if there is no instantaneous interruption in the wireless power supply from the wireless tag reader 1.

  The ID information extraction unit 26 extracts ID information (for example, reader ID) superimposed on the high-frequency power received by the matching circuit unit 22 and notifies the tag control unit 20 of the ID information. This extraction of ID information is processing corresponding to the wireless tag 2 side in S230 of FIG. The tag ID storage unit 27 stores its own tag ID.

  When there are a plurality of wireless tags 2 in the area where the wireless tag reader 1 is wirelessly powered, the delay time calculation unit 28 transmits IDs at the same time and the tag ID information collides. In order to prevent the phenomenon, a delay time for shifting the ID transmission timing for each wireless tag 2 is generated. The delay time may be a different value for each tag ID. For example, if the ID value is a value obtained by multiplying a predetermined constant, the same delay time does not exist. The generated delay time is notified to the tag control unit 20. In addition, the delay time of a different value for every tag ID may be memorize | stored in the tag control part 20 previously, In that case, the delay time calculating part 28 does not need.

  The notification condition registration unit 29 registers a condition for notifying its own tag ID stored in the tag ID storage unit 27. For example, if the condition is such that the tag ID is notified only to a specific wireless tag reader 1, the reader ID of the specific wireless tag reader 1 is registered. Further, if it is a condition to react to the wireless tag reader 1 searching for its own wireless tag, it is sufficient to register its own tag ID stored in the tag ID storage unit 27 in the notification condition registration unit 29 as well. .

  Then, when the ID information extracted by the ID information extraction unit 26 matches the ID information registered in the notification condition registration unit 29, the tag control unit 20 notifies the wireless tag reader 1 of the tag ID. do it. Furthermore, when the ID information is not registered in the notification condition registration unit 29, the tag control unit 20 may react unconditionally to wireless power feeding and notify the wireless tag reader 1 of its tag ID. The registration of ID information in the notification condition registration unit 29 can be realized by writing with a normal wireless tag writer, for example.

  Heretofore, an example of the embodiment of the present invention has been described. Although the magnetic resonance type wireless power feeding has been described as an example of the embodiment of the present invention, it goes without saying that an electromagnetic coupling type wireless power feeding or the like may be used. In addition, since the wireless tag side responds to a specific resonance frequency in the case of the magnetic field resonance type, the resonance frequency may be changed for each type of the wireless tag.

  According to the present invention, the readable range can be set relatively freely as in the conventional active type, and ID information can be efficiently read from an unspecified number of wireless tags that do not require battery replacement in the conventional passive type. It is possible to provide a wireless tag reader and a wireless tag compatible with wireless power feeding.

  In particular, it is possible to register a notification condition on the wireless tag side and control whether or not to notify the tag ID according to the notification condition. Therefore, it reacts only when a specific wireless tag reader or a specific tag ID is notified. Target-specific RFID tag system (for example, inventory management for special goods), general-purpose RFID tag system that responds to any RFID tag reader (for example, general inventory management), target-specific RFID tag and general-purpose It is possible to provide a flexible wireless tag system such as a mixed wireless tag system in which mixed wireless tags are mixed.

DESCRIPTION OF SYMBOLS 1 ... Wireless tag reader 2 ... Wireless tag 10 ... Reader control part 11 ... Power supply part 12 ... High frequency power supply part 13 ... Matching circuit part 14 ... ID information superimposition part 15 ... Current fluctuation detection unit 16 ... feed device 17 ... tag ID extraction unit 18 ... reader ID storage unit 19 ... display unit 20 ... tag control unit 21 ... power receiving device 22 ... Matching circuit unit 23 ... power conversion unit 24 ... load fluctuation unit 25 ... power storage unit 26 ... ID information extraction unit 27 ... tag ID storage unit 28 ... delay time calculation unit 29 ...・ Notification condition registration part

Claims (6)

A wireless tag reader that supplies power to a predetermined wireless tag in a non-contact manner and receives tag ID information notified by the wireless tag,
Wireless power supply means for generating a varying electric field or magnetic field and supplying power to the wireless tag, current value fluctuation detection means for detecting a current value fluctuation of a current flowing through a predetermined part of the wireless power supply means, and the current value Tag ID information extracting means for extracting tag ID information included in the current value fluctuation detected by the fluctuation detecting means,
When the wireless power supply means supplies power to the wireless tag, the tag ID information extraction means when the current value fluctuation detection means detects a current value fluctuation caused by load fluctuation on the wireless tag side. Extracts a tag ID information included in the current value fluctuation, a load fluctuation type wireless tag reader. The wireless tag reader according to claim 1,
The information superimposing unit further superimposes predetermined information on a fluctuating electric field or magnetic field output from the wireless power feeding unit, and the information superimposing unit converts the ID information related to the own radio tag reader or the radio tag to be read into the fluctuating electric field. Alternatively, a load fluctuation type wireless tag reader that is superimposed on a magnetic field. The wireless tag reader according to claim 2,
When the ID information is superimposed on the fluctuating electric field or magnetic field output by the wireless power supply means and output, if the current value fluctuation detection means does not detect a current value fluctuation within a predetermined time, the wireless power supply means The load fluctuation type wireless tag reader is characterized in that information indicating that the target wireless tag does not exist in the vicinity is displayed on a display unit included in the wireless tag reader. A wireless tag that receives power in a non-contact manner by wireless power feeding from a predetermined wireless tag reader and notifies tag ID information stored in the wireless tag,
Wireless power receiving means for receiving power in a non-contact manner by a fluctuating electric field or magnetic field generated by the wireless tag reader, ID information storage means for storing tag ID information, and a predetermined load for applying the power received by the wireless power receiving means Load variation means for electronically varying the value of ID, and ID information notification means for controlling the load variation means to notify the tag ID information to the wireless tag reader,
When the wireless power receiving means receives power, the ID information notifying means controls the load changing means to change the value of the load according to the tag ID information. . The wireless tag according to claim 4,
ID information extracting means for extracting ID information notified by the wireless tag reader superimposed on the fluctuating electric field or magnetic field, and if the ID information extracting means extracts predetermined ID information, The ID information notification means notifies the tag ID information to the wireless tag reader. If the reader ID information extraction means does not extract predetermined ID information, the ID information notification means transmits the tag ID information to the wireless tag reader. A load variation type wireless tag characterized by not being notified to a tag reader. A wireless tag reader or a wireless tag according to any one of claims 1 to 5,
The load fluctuation type radio tag reader or radio tag characterized in that the wireless power feeding means or the wireless power receiving means is a magnetic field resonance system that resonates at a specific frequency.

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