JP2008021188A - Transmitting/receiving system and transmitting/receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitting/receiving system and a transmitting/receiving method that can manage the amount of content by detecting the location of a wireless transmission device. <P>SOLUTION: Carrier wave whose frequency is 13.56 MHz is exchanged between an external transmitting/receiving device 10 and the wireless transmission device 20 according to a load modulation system. The external transmitting/receiving device 10 sequentially transmits a plurality of transmission signals whose amplitude levels are different from each other, by sequentially changing the transmission level of the carrier wave. The wireless transmission device 20 obtains a communication distance between the external transmitting/receiving device 10 and the wireless transmission device 20 based on the transmission level of the transmission signal when the receiving state of the transmission signals from the external transmitting/receiving device 10 meets predetermined conditions. The wireless transmission device 20 transmits a reply signal by applying load modulation to the carrier wave from the external transmitting/receiving device based on the reply signal including distance information showing the obtained communication distance. The external transmitting/receiving device 10 detects the distance information out of the reply signal from the wireless transmission device 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission / reception system in which a wireless transmission device and an external transmission / reception device communicate according to a load modulation method, and a transmission / reception method executed between the wireless transmission device and the external transmission / reception device according to a load modulation method.

  In recent years, a transmission / reception system in which an external transmission / reception device and a wireless transmission device exchange data signals in a non-contact manner using radio waves in a radio frequency band has been put into practical use. A typical example of a wireless transmission device is a so-called RFID (Radio Frequency Identification) tag. RFID tags are also called wireless tags, and are used in various frequency bands.

  For example, in a wireless tag (so-called IC card) having a communication frequency of 13.56 MHz, the following communication is performed between an external transmission / reception device (for example, a reader / writer) and a wireless transmission device (for example, a wireless tag). Is executed. Here, a case where the reply method from the wireless tag is a load modulation method will be described.

  First, in the reader / writer, a 13.56 MHz carrier wave is amplitude-modulated (Amplitude Shift Keying; ASK) based on transmission data, and an electromagnetic wave (or microwave) corresponding to the modulated carrier wave is transmitted from the transmission / reception coil.

  Next, in the wireless tag, the electromagnetic wave from the reader / writer is received by the transmission / reception coil, and power supply power for operation of the internal circuit is generated. Some wireless tags include a driving power source such as a battery. In that case, driving power may not be generated from a received signal. Also, transmission data is restored from the modulated carrier wave by the demodulation circuit, and the microcomputer mounted on the wireless tag reads reply data (for example, a data string stored in the storage unit) according to the transmission data. Further, the output circuit of the wireless tag amplitude-modulates a subcarrier (for example, 212 kHz subcarrier) based on the return data, and changes the impedance to the transmission / reception coil in accordance with the modulation subcarrier.

  On the other hand, the reader / writer transmits an electromagnetic wave corresponding to a carrier wave having a constant amplitude. Here, according to the impedance change in the wireless tag, the impedance of the reader / writer with respect to the transmission / reception coil also changes. As a result, the carrier wave in the reader / writer is load-modulated, so that the sub-carrier corresponding to the return data is sent from the wireless tag.

  In this way, the reader / writer can acquire the information stored in the wireless tag in a non-contact manner.

  The range in which the external transmission / reception device can communicate with the wireless transmission device is determined by the strength of the signal (radio wave) from the external transmission / reception device. That is, in the conventional transmission / reception system, in order to ensure a certain communicable range, the external transmission / reception apparatus is set to transmit a signal at a certain level according to the communicable range.

The transmission / reception system can be applied to various fields. For example, a wireless tag is attached to the storage container, and data (for example, type, concentration, date of manufacture, etc.) relating to the contents (solid, liquid, or gas) stored in the storage container is stored in the wireless tag. . If it does in this way, the information regarding the contents can be easily acquired without contact, and the contents stored in the storage container can be recognized. Such recognition of the contents is necessary, for example, for a DMFC (direct methanol fuel cell) that generates power using a methanol aqueous solution as a direct fuel. In DMFC, it is important to manage the concentration of aqueous methanol solution that serves as fuel in order to generate electricity smoothly and obtain maximum output.
JP-A-9-130999

  However, in the conventional transmission / reception system, it is assumed that information can be surely exchanged between the external transmission / reception device and the wireless transmission device without contact. That is, it is assumed that the wireless transmission device exists in a communicable range (a range in which the external transmission / reception device and the wireless transmission device can communicate). Therefore, the case where the wireless transmission device does not exist within the communicable range is not discussed. In the conventional transmission / reception system, the wireless transmission device only communicates with the external transmission / reception device in response to a signal from the external transmission / reception device, and a device for detecting the location of the wireless transmission device has been proposed in the past. It has not been.

  In addition, when a product such as liquid or gas is stored and handled in a storage container, it is often required to manage the content of the contents stored in the storage container. For example, in DMFC, it is necessary to manage the remaining amount of aqueous methanol solution in order to continue power generation. In general, when the contents are liquid, the contents can be managed by estimating the liquid level based on the conductivity or dielectric constant of the contents, or by using ultrasonic reflection. There is a way to estimate the level. However, since the number of parts of the circuit for estimating the liquid level is large, the circuit scale is large and the cost is high, so that there is a problem that the practicality is low.

  An object of the present invention is to detect the location of a wireless transmission device. More specifically, an object of the present invention is to provide a system capable of managing the internal capacity by detecting the location of a wireless transmission device.

  According to one aspect of the present invention, an external transmission / reception device and a wireless transmission device communicate in a transmission / reception system. The external transmission / reception apparatus sequentially transmits a plurality of transmission signals having different amplitude levels by transmitting a carrier wave and sequentially changing the transmission level of the carrier wave. The wireless transmission device performs load modulation on the carrier wave from the external transmission / reception device. The wireless transmission device includes a first transmission / reception unit, a signal state detection unit, a first control unit, and a reply signal supply unit. The first transmission / reception unit receives a carrier wave from the external transmission / reception device. The signal state detection unit detects the reception state of the transmission signal received by the first transmission / reception unit. When the reception state of the transmission signal detected by the signal state detection unit satisfies a predetermined condition, the first control unit determines whether the transmission between the external transmission / reception device and the wireless transmission device is based on the transmission level of the transmission signal. The communication distance is obtained, and reply information including distance information indicating the obtained communication distance is output. The reply signal supply unit generates a reply signal based on the reply information from the first control unit, and supplies the generated reply signal. The first transmission / reception unit transmits the response signal by load-modulating the carrier wave from the external transmission / reception device based on the response signal supplied by the response signal supply unit. The reply signal includes distance information indicating the communication distance obtained by the second control unit. The external transmission / reception device includes a second control unit, a transmission signal supply unit, a level setting unit, a second transmission / reception unit, and an information detection unit. The second control unit sequentially outputs a plurality of level information indicating different amplitude levels, and sequentially outputs a plurality of transmission information. The transmission signal supply unit supplies a carrier wave and, upon receiving transmission information from the second control unit, supplies a transmission signal by modulating the carrier wave based on the transmission information. The level setting unit sets the transmission level of the carrier wave supplied from the transmission signal supply unit to the amplitude level indicated in the level information output from the first control unit. The second transmission / reception unit transmits a carrier wave whose transmission level is set by the level setting unit. The second transmitting / receiving unit receives a reply signal transmitted by load modulation in the wireless transmission device. The information detection unit detects distance information from the reply signal received by the second transmission / reception unit.

  In the transmission / reception system, the communication distance can be determined by the transmission level of the transmission signal and the reception state of the transmission signal. Here, when the reception state of the transmission signal is a predetermined state, the first control unit considers the relationship between the transmission level of the transmission signal and the communication distance, and based on the transmission level of the transmission signal. Communication distance. Thus, since the distance to the wireless transmission device can be obtained, the location of the wireless transmission device can be detected.

  Preferably, the transmission information output from the second control unit includes level information output together with the transmission information among the plurality of level information. The first control unit detects level information from the transmission signal received by the first transmission / reception unit, and the reception state of the transmission signal detected by the signal state detection unit satisfies a predetermined condition. Then, the communication distance is obtained based on the amplitude level indicated in the detected level information.

  In the transmission / reception system, the transmission level of each of the plurality of transmission signals is the amplitude level indicated by the level information included in the transmission signal. The first control unit can grasp the transmission level of the transmission signal from the level information included in the transmission signal.

  Preferably, the second control unit measures an elapsed time from the time when the first transmission signal is transmitted by the second transmission / reception unit, and outputs level information indicating an amplitude level corresponding to the elapsed time. . The first control unit measures an elapsed time from the time when the first transmission signal is received by the first transmission / reception unit, and the reception state of the transmission signal detected by the signal state detection unit is a predetermined condition. The communication distance is obtained based on the elapsed time when it is determined that the above is satisfied.

  In the transmission / reception system, the external transmission / reception device sequentially transmits a plurality of transmission signals by sequentially updating the amplitude level indicated in the level information according to a predetermined timing after the first transmission signal is transmitted. . The first control unit can grasp the amplitude level (transmission level) of the transmission signal transmitted from the external transmission / reception device by managing the elapsed time.

  Preferably, the second control unit counts the number of transmissions of the transmission signal by the second transmission / reception unit, and outputs level information indicating an amplitude level corresponding to the number of transmissions. The first control unit counts the number of times the transmission signal is received by the first transmission / reception unit, and determines that the reception state of the transmission signal detected by the signal state detection unit satisfies a predetermined condition. The communication distance is obtained based on the number of receptions.

  In the transmission / reception system, the external transmission / reception device transmits a plurality of transmission signals by sequentially updating the amplitude level indicated in the level information in accordance with the number of transmissions of the transmission signal. The first control unit can grasp the amplitude level (transmission level) of the transmission signal transmitted from the external transmission / reception device by managing the number of receptions of the transmission signal.

  Preferably, the signal state detection unit measures an amplitude level of a transmission signal received by the first transmission / reception unit. When the amplitude level of the transmission signal measured by the signal state detection unit is a predetermined level, the first control unit determines that the transmission state of the transmission signal satisfies a predetermined condition.

  Preferably, the signal state detection unit counts the number of error locations occurring in the transmission signal received by the first transmission / reception unit. The first control unit determines that the reception state of the transmission signal satisfies a predetermined condition when the number of error points counted by the signal state detection unit is a predetermined number.

  Preferably, when the transmission signal supply unit receives the transmission information from the second control unit, the transmission signal supply unit generates a transmission signal provided with a section corresponding to the transmission information and having a continuous fluctuation in amplitude level. Supply the generated transmission signal.

  In the above transmission / reception system, the signal state detection unit can acquire an accurate reception state when detecting the reception state of the transmission signal in a section in which the amplitude level of the transmission signal continues to vary. Thereby, it is possible to accurately determine whether or not the reception state of the transmission signal satisfies a predetermined condition.

  Further, in order to generate a reply signal having a section in which the fluctuation of the amplitude level continues, for example, the transmission signal supply unit multiplies the transmission information with a data string indicating a random data value, and based on the transmission information A transmission signal may be generated by modulating a carrier wave. As a result, the amplitude level of the transmission signal continuously fluctuates in a section of the transmission signal multiplied by a random data string.

  Preferably, the transmission / reception system further includes a storage container. The storage container is provided with the wireless transmission device so that the predetermined content is stored and the communication distance is changed according to the increase or decrease of the content of the content. The second control unit further determines the content of the predetermined content based on the communication distance indicated in the distance information detected by the information detection unit.

  In the above transmission / reception system, the control unit can derive the internal capacity from the communication distance in consideration of the relationship between the communication distance and the internal capacity. Thereby, the content volume of the content accommodated in the storage container can be managed.

  Preferably, the transmission / reception system further includes a storage container in which predetermined content that is liquid is stored, and a floating member that floats on a liquid surface of the predetermined content stored in the storage container. The wireless transmission device is provided on the surface of the floating member. The second control unit obtains the content of the predetermined content stored in the storage container based on the communication distance indicated by the distance information detected by the information detection unit.

  In the transmission / reception system, the floating member moves up and down in accordance with the increase or decrease in the content of the contents stored in the storage container. Further, the communication distance also changes according to the fluctuation of the internal capacity. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the content volume of the content accommodated in the storage container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmitting / receiving unit of the external transmission / reception device is moved to a position corresponding to the moving direction of the floating member (for example, the moving direction of the floating member). It may be arranged on the extension line).

  Preferably, the transmission / reception system further includes a storage container in which predetermined contents are stored, and a partition member. The partition member is disposed inside the storage container and moves in accordance with an increase or decrease in the internal volume of the predetermined content stored in the storage container. The wireless transmission device is provided on the partition member. The second control unit obtains the content of the predetermined content stored in the storage container based on the communication distance indicated by the distance information detected by the information detection unit.

  In the transmission / reception system, the communication distance also changes according to the increase / decrease in the content of the contents stored in the storage container. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the content volume of the content accommodated in the storage container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmitting / receiving unit of the external transmission / reception device is positioned at a position corresponding to the moving direction of the partition member (for example, the moving direction of the partition member). On the extension line).

  Preferably, the transmission / reception system further includes a storage container in which a predetermined content is stored and whose outer shape expands and contracts in accordance with an increase or decrease in the internal volume of the content. The wireless transmission device is provided on the surface of the container. The second control unit obtains the content of the predetermined content stored in the storage container based on the communication distance indicated by the distance information detected by the information detection unit.

  In the transmission / reception system, the communication distance also changes according to the increase / decrease in the content of the contents stored in the storage container. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the content volume of the content accommodated in the storage container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmission / reception unit of the external transmission / reception device is positioned corresponding to the expansion / contraction direction of the container (for example, on the extension line in the expansion / contraction direction). It should just be arranged.

  Preferably, the transmission / reception system further includes a fuel cell unit including a power generation unit that generates power using liquid fuel. The storage container stores liquid fuel used by the power generation unit. The second control unit obtains the internal volume of the liquid fuel stored in the storage container based on the communication distance indicated by the distance information detected by the information detection unit.

  In the transmission / reception system, the internal volume of the liquid fuel stored in the storage container can be managed.

  Preferably, the transmission / reception system further includes an infusion storage container for storing a predetermined infusion solution, a floating member floating on a liquid surface of the predetermined infusion solution stored in the infusion solution storage container, and a container mounting portion for attaching the infusion solution storage container. The wireless transmission device is provided on the surface of the floating member. The second control unit obtains the internal volume of the predetermined infusion stored in the infusion container based on the communication distance indicated by the distance information detected by the information detection unit.

  In the transmission / reception system, the floating member moves up and down in accordance with the increase / decrease in the volume of the infusion contained in the infusion container. Further, the communication distance also changes according to the fluctuation of the internal capacity. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the internal volume of the infusion accommodated in the infusion solution container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmitting / receiving unit of the external transmission / reception device is positioned at a position corresponding to the moving direction of the floating member (for example, the container mounting portion of the container mounting stand). ).

  Preferably, the transmission / reception system further includes a printer. The printer includes a paper feed tray for storing printer paper and a printer main body. The printer main body includes a tray storage unit in which a paper feed tray is inserted to store the paper feed tray. The paper feed tray includes a paper feed tray main body, a paper feed plate, and an urging member. The paper feed plate is disposed inside the paper feed tray main body and on which printer paper is placed. The biasing member connects one end of the bottom surface of the paper feed tray main body and one end of the paper feed plate in the insertion direction of the paper feed tray, and biases the paper feed plate in a direction away from the bottom surface of the tray main body. The wireless transmission device is provided at one end of the sheet feeding plate. The second control unit obtains the number of printer sheets stored in the paper feed tray based on the communication distance indicated by the distance information detected by the information detection unit.

  In the above transmission / reception system, when the number of sheets of printer paper decreases, one end of the sheet feeding plate moves away from the bottom surface of the tray body by the restoring force of the spring. Thereby, the communication distance also changes. Considering the relationship between the communication distance and the number of sheets, the control unit can derive the number of sheets from the communication distance. As a result, the number of printer sheets stored in the sheet feed tray can be managed. In order to make the relationship between the communication distance and the number of sheets unambiguous, for example, the second transmission / reception unit of the external transmission / reception device is moved to a position corresponding to the moving direction of the sheet feeding plate (for example, the upper surface of the tray storage unit). ).

  Preferably, the transmission / reception system further includes a printer. The printer includes an ink cartridge that stores predetermined ink, a floating member that floats on a liquid surface of the ink stored in the ink cartridge, and a printer main body that has a cartridge holder portion that stores the ink cartridge therein. The wireless transmission device is provided on the surface of the floating member. The second control unit obtains the internal volume of the ink stored in the ink cartridge based on the communication distance indicated in the distance information detected by the information detection unit.

  In the transmission / reception system, the floating member moves up and down in accordance with the increase or decrease in the content of the ink stored in the ink cartridge. Further, the communication distance also changes according to the fluctuation of the internal capacity. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the internal volume of the ink accommodated in the ink cartridge can be managed. In order to unify the relationship between the communication distance and the internal capacity, for example, the second transmission / reception unit of the external transmission / reception device may be installed at a position corresponding to the moving direction of the floating member.

  Preferably, the wireless transmission device further includes a storage unit that stores content information that is information regarding the content. The first control unit outputs reply information including distance information indicating the obtained communication distance and content information stored in the storage unit. The information detection unit detects the distance information and content information from the reply signal received by the second transmission / reception unit. The external transmission / reception device further includes a display unit that displays at least one of the content obtained by the second control unit and the content information detected by the information detection unit.

  In the transmission / reception system, it is possible to visually manage the content of the contents and information about the contents.

  According to another aspect of the present invention, the transmission / reception method is executed by an external transmission / reception device and a wireless transmission device. The external transmission / reception apparatus can change the transmission level of the carrier wave. The wireless transmission device performs load modulation on the carrier wave from the external transmission / reception device. The transmission / reception method includes a transmission step, a carrier wave reception step, a state detection step, a calculation step, a generation step, a reply step, a reply signal reception step, and a detection step. In the transmission step, the external transmission / reception apparatus sequentially transmits a plurality of transmission signals having different amplitude levels by transmitting the carrier wave and sequentially changing the transmission level of the carrier wave. In the carrier wave reception step, the wireless transmission device receives the carrier wave transmitted in the transmission step. In the state detection step, the wireless transmission device detects the reception state of the transmission signal received in the carrier wave reception step. In the calculating step, if the reception state of the transmission signal detected in the state detection step satisfies a predetermined condition, the external transmission / reception device, the wireless transmission device, and the like based on the transmission level of the transmission signal Find the communication distance between. In the generation step, the wireless transmission device generates a reply signal including distance information indicating the communication distance obtained in the calculation step. In the reply step, the wireless transmission apparatus performs load modulation on the carrier wave from the external transmission / reception apparatus based on the reply signal generated in the generation step, thereby transmitting the reply signal. In the reply signal receiving step, the external transmission / reception apparatus receives the reply signal transmitted in the reply step. In the detecting step, distance information is detected from the reply signal received in the reply signal receiving step.

  In the transmission / reception method, the communication distance can be determined by the transmission level of the transmission signal and the reception state of the transmission signal. Here, when the reception state of the transmission signal is a predetermined state, the communication distance is determined based on the transmission level of the transmission signal in consideration of the relationship between the transmission level of the transmission signal and the communication distance in the calculation step. Can be requested. Thus, since the distance to the wireless transmission device can be obtained, the location of the wireless transmission device can be detected.

  Preferably, in the transmission step, a transmission signal is transmitted by changing the transmission level of the carrier wave and modulating the carrier wave based on transmission information including level information indicating the transmission level. In the calculation step, the wireless transmission device detects level information from the transmission signals received in the carrier wave reception step, and the reception state of the transmission signals detected in the state detection step satisfies a predetermined condition. If so, the communication distance is obtained based on the amplitude level indicated in the detected level information.

  Preferably, the transmission / reception method further includes a transmission elapsed time timing step and a reception elapsed time timing step. In the transmission elapsed time counting step, the external transmission / reception apparatus measures the elapsed time from the time when the first transmission signal among the plurality of transmission signals is transmitted in the transmission step. In the reception elapsed time counting step, the wireless transmission device measures the elapsed time from the time when the first transmission signal is received in the carrier wave reception step. In the transmission step, when the external transmission / reception device transmits the transmission signal, the transmission level of the transmission signal is set to an amplitude level corresponding to the elapsed time measured in the transmission elapsed time counting step. In the calculation step, the communication distance is obtained based on the elapsed time measured in the reception elapsed time counting step when it is determined that the reception state of the transmission signal detected in the state detection step satisfies a predetermined condition. .

  Preferably, the transmission / reception method further includes a transmission number counting step and a reception number counting step. In the transmission count counting step, the external transmission / reception device counts the number of transmissions of the transmission signal in the transmission step. In the reception frequency counting step, the wireless transmission device counts the reception frequency of the transmission signal in the carrier wave reception step. In the transmission step, when the external transmission / reception apparatus transmits the transmission signal, the transmission level of the transmission signal is set to an amplitude level corresponding to the number of transmissions counted in the transmission number counting step. In the calculation step, based on the number of receptions counted in the reception number counting step when the wireless transmission device determines that the reception state of the transmission signal detected in the state detection step satisfies a predetermined condition. The communication distance is obtained.

  As described above, since the communication distance between the external transmission / reception device and the wireless transmission device can be obtained, the location of the wireless transmission device can be detected. Moreover, the internal volume of the content accommodated in the predetermined storage container can be managed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(First embodiment)
<Overall configuration>
FIG. 1 shows an overall configuration of a transmission / reception system according to a first embodiment of the present invention. In this system, a carrier wave of a predetermined frequency (here, 13.56 MHz) is exchanged between the external transmission / reception device 10 and the wireless transmission device 20 in accordance with the load modulation method. The external transmission / reception device 10 is, for example, a reader / writer. The wireless transmission device 20 is, for example, an RFID (Radio Frequency Identification) tag, and stores ID information that is a data string unique to itself.

  The external transmission / reception device 10 transmits the carrier wave and sequentially changes the amplitude level of the carrier wave to be transmitted (transmission level of the carrier wave). As a result, a plurality of transmission signals having different amplitude levels are sequentially transmitted. The external transmission / reception device 10 amplitude-modulates the carrier wave based on the transmission information. The transmission information includes, for example, a command (reply command information) for instructing a reply of predetermined information (for example, ID information).

  The wireless transmission device 20 receives a carrier wave from the external transmission / reception device 10. When the reception state of the transmission signal satisfies a predetermined condition, the wireless transmission device 20 obtains the communication distance based on the amplitude level at the time of transmission of the transmission signal (transmission level of the transmission signal). The communication distance corresponds to the distance between the external transmission / reception device 10 and the wireless transmission device 20. The wireless transmission device 20 generates a return signal including distance information indicating the obtained communication distance, and load-modulates a carrier wave from the external transmission / reception device based on the generated return signal. By this load modulation, a component corresponding to the return signal is superimposed on the carrier wave. That is, a reply signal is transmitted. Further, the return signal may include ID information.

  Also, the external transmission / reception device 10 acquires a reply signal by extracting a component corresponding to the reply signal from the carrier wave that has been load-modulated. The external transmission / reception device 10 detects the distance information from the return signal, and acquires the communication distance indicated by the detected distance information.

<Relationship between signal level and communication distance>
Here, the relationship between the signal level and the communication distance will be described.

  FIG. 2 shows the relationship between the communication distance and the amplitude level of the carrier wave received by the wireless transmission device 20 (the reception level of the transmission signal). As shown in FIG. 2, the amplitude level (reception level) of the signal received by the receiving apparatus increases as the amplitude level (transmission level) of the signal transmitted by the transmitting apparatus increases. In addition, the reception level decreases as the distance between the transmission-side device and the reception-side device increases. As the signal transmission level increases, the relationship between the signal reception level and the communication distance changes in order of “curve A”, “curve B”, and “curve C”. Further, when the transmission level is constant, the relationship between the reception level and the communication distance is, for example, a curve A. In this case, as the communication distance increases to “D1”, “D2”, and “D3”, the signal reception level decreases to “L1”, “L2”, and “L3”.

  From the above, “communication distance” means “amplitude level of carrier wave transmitted from external transmission / reception device 10 (transmission level of transmission signal)” and “amplitude level of transmission signal in external transmission / reception device 10 (reception level of transmission signal)” ) ". Here, if the “transmission signal reception level” is a predetermined fixed value, the correspondence between the “transmission signal transmission level” and the “communication distance” can be uniquely determined.

<Relationship between number of errors and communication distance>
Next, the correspondence between the number of signal error locations and the communication distance will be described.

  FIG. 3A shows the relationship between “communication distance” and “communication S / N” when the signal transmission level is constant. As described above, when the signal transmission level is constant, the signal reception level decreases as the communication distance increases. Here, assuming that the noise in the communication path between the external transmission / reception device 10 and the wireless transmission device 20 is constant, the communication S / N decreases as the communication distance increases, and the signal received by the reception-side device. It is easy for errors to occur.

  FIG. 3B shows the relationship between “error rate (error rate in a signal received by a receiving device)” and “communication S / N” when the signal transmission level is constant. When the signal transmission level is constant, the smaller the communication S / N, the higher the error rate in the signal received by the receiving device.

  FIG. 3C shows the relationship between “the number of error locations (the number of error locations generated in a signal received by the receiving apparatus)” and “communication distance” when the signal transmission level is constant. 3A and 3B, the longer the communication distance, the greater the number of error locations in the signal received by the receiving apparatus.

  As described above, “communication distance” can be expressed as a function of “transmission level of transmission signal” and “number of error locations in transmission signal received by wireless transmission device 20”. Here, if the “number of error locations” is a predetermined fixed value, the correspondence between “transmission level of transmission signal” and “communication distance” can be uniquely determined.

  In summary, “communication distance” can be expressed as a function of “transmission level of transmission signal” and “reception state of transmission signal”. Here, when the “transmission signal reception state” is in a predetermined state, the correspondence between “transmission signal transmission level” and “communication distance” can be uniquely determined.

<Internal configuration of external transmission / reception device>
FIG. 4 shows an internal configuration of the external transmission / reception apparatus 10 shown in FIG. The external transmission / reception device 10 includes a control unit 11, a transmission signal supply unit 12, a transmission / reception unit 13, a level setting unit 14, and a decoding unit 15.

  The control unit 11 is, for example, a microcomputer. When receiving an information acquisition command from the host computer, the control unit 11 sequentially outputs a plurality of level information indicating different amplitude levels and sequentially outputs a plurality of transmission information. Here, each of the plurality of pieces of transmission information includes level information output together with the transmission information and reply command information that is a data string indicating a command for causing the wireless transmission device 20 to send a reply signal. .

  The transmission signal supply unit 12 performs amplitude modulation on a carrier wave (for example, an amplitude level of 100 V and a frequency of 13.56 MHz) based on transmission information from the control unit 11. That is, the transmission signal supply unit 12 generates a transmission signal based on the transmission information and supplies the generated transmission signal. Further, when the transmission signal supply unit 12 completes the supply of the transmission signal, the control unit 11 causes the transmission signal supply unit to supply a carrier wave having a constant amplitude (for example, a carrier wave having an amplitude level of 100 V and a frequency of 13.56 MHz).

  The transceiver 13 includes a tuning capacitor C1, a variable resistor R1, and a transceiver coil L1. The transmission / reception coil L1 transmits an electromagnetic wave corresponding to the carrier wave supplied from the transmission signal supply unit 12. That is, the transmission / reception unit 13 transmits the carrier wave from the transmission signal supply unit 12. In addition, when load modulation is performed in the wireless transmission device 20, a component corresponding to predetermined information is superimposed on the carrier wave in the transmission / reception unit 13. That is, the transmission / reception unit 13 receives a reply signal from the wireless transmission device 20. Here, the reply signal includes ID information unique to the wireless transmission device and distance information indicating the communication distance obtained by the wireless transmission device 20.

  The level setting unit 14 sets the transmission level of the carrier wave transmitted from the transmission / reception unit 13 to the amplitude level indicated in the level information output from the control unit 11. Specifically, the level setting unit 14 sets the resistance value of the variable resistor R1 of the transmission / reception unit 13 so that the transmission level of the carrier wave becomes the amplitude level indicated in the level information. As a result, the amplitude level of the transmission signal transmitted from the transmission / reception unit 13 (transmission level of the transmission signal) becomes the amplitude level indicated in the level information included in the transmission signal.

  The decoding unit 15 extracts a component corresponding to the return signal from the load-modulated carrier wave. Further, the decoding unit 15 generates reply information by performing amplification, demodulation, and decoding of the amplitude level on the extracted reply signal, and detects ID information and distance information from the generated reply information.

  The control unit 11 acquires distance information and ID information detected by the decoding unit 15 and outputs measurement result information including the acquired distance information and ID information to the host computer.

<< Internal configuration of transmission signal supply unit >>
FIG. 5 shows an internal configuration of the transmission signal supply unit 12 shown in FIG. The transmission signal supply unit 12 includes an encoding processing unit 101, an error correction code addition unit 102, a transmission data generation unit 103, and a modulation circuit 104.

  The encoding processing unit 101 encodes transmission information from the control unit 11 to generate transmission data.

  The error correction code adding unit 102 performs a predetermined operation on the transmission data generated by the encoding processing unit 101 to generate an error correction code. The error correction code is, for example, a Reed-Solomon code. Thereafter, the error correction code adding unit 102 adds the generated error correction code to the transmission data.

  The transmission data generation unit 103 adds a header to the transmission data (transmission data to which the error correction code is added) from the error correction code addition unit 102. The header includes a synchronization signal and a communication start identifier.

  The modulation circuit 104 modulates a carrier wave based on transmission data (transmission data with a header added) from the transmission data generation unit 103. For example, the modulation circuit 104 supplies a carrier wave having a high amplitude level (for example, a carrier wave having an amplitude level of 100 V) to the transmission / reception unit 13 during a period in which the data value of the transmission data from the transmission data generation unit 103 is “1”. In the period when the data value of the transmission data is “0”, a carrier wave having a relatively low amplitude level (for example, a carrier wave having an amplitude level of 90 V) is supplied to the transmission / reception unit 13. This carrier wave is generated by an oscillator (not shown) or the like. In this way, the modulation circuit 104 supplies the modulated carrier wave to the transmission / reception unit 13 as a transmission signal.

  In addition, when the transmission data output from the transmission data generation unit 103 is completed, the modulation circuit 104 receives a control from the control unit 11 and supplies a constant amplitude carrier wave. For example, in order to supply a constant amplitude carrier wave, the control unit 11 outputs predetermined data having a data value “1” to the modulation circuit 104, and the modulation circuit 104 outputs a carrier wave having a relatively high amplitude level to the constant amplitude carrier wave. Supply as.

  For example, in the external transmission / reception device 10, the carrier wave (FIG. 6A) is amplitude-modulated based on the transmission data (FIG. 6B). Further, the transmission level of the carrier wave becomes the amplitude level (FIG. 6C) indicated in the level information. Therefore, the transmission signal transmitted from the external transmission / reception device 10 is as shown in FIG. 6D.

<< Internal Configuration of Decoding Unit and Signal State Detection Unit >>
FIG. 7 shows an internal configuration of the decoding unit 15 shown in FIG. The decoding unit 15 includes a reception amplification circuit 105, a demodulation circuit 106, an error correction circuit 107, a decoding processing unit 108, and an information detection unit 109.

  The reception amplification circuit 105 extracts a component corresponding to the return signal from the carrier wave that has been load-modulated in the transmission / reception unit 13. Here, the reception amplifier circuit 105 extracts a predetermined frequency band (here, a frequency band corresponding to the data value “1” of the reply data, which is 13.56 MHz ± 212 kHz).

  Further, the reception amplifier circuit 105 amplifies the amplitude level of the extracted reply signal to a predetermined level. For example, the reception amplification circuit 105 amplifies the reply signal with reference to the transmission level of the constant amplitude carrier wave supplied by the transmission signal supply unit 12. Further, for example, the reception amplification circuit 105 may automatically adjust the amplitude level of the return signal so that it always becomes a constant amplitude of 1 Vp-p regardless of the transmission level of the carrier wave.

  The demodulation circuit 106 demodulates the reply signal amplified by the reception amplification circuit 105 and generates reply data. Note that a header and an error correction code are added to the reply data.

  The error correction circuit 107 executes error correction processing on the return data using the error correction code added to the return data from the demodulation circuit 106.

  The decoding processing unit 108 decodes the reply data that has been corrected by the error correction circuit 107, and generates reply information. Here, the reply information includes ID information and distance information of the wireless transmission device 20.

  The information detection unit 109 detects ID information and distance information from the reply information generated by the decoding processing unit 108.

<Internal configuration of wireless transmission device>
FIG. 8 shows an internal configuration of the wireless transmission device 20 shown in FIG. The wireless transmission device 20 includes a storage unit 21, a transmission / reception unit 22, a voltage generation unit 23, a decoding unit 24, a signal state detection unit 25, a control unit 26, and a reply signal supply unit 27.

  The storage unit 21 is, for example, an EEPROM, and stores a data string indicating ID information unique to the wireless transmission device 20.

  The transmitter / receiver 22 includes a transmitter / receiver coil L2, a tuning capacitor C2, a series resistor R2, and a switch SW. When the transmission / reception coil L2 receives an electromagnetic wave from the external transmission / reception device 10, an AC voltage corresponding to the electromagnetic wave is generated in the transmission / reception unit 22 by electromagnetic induction. That is, the transmission / reception unit 22 receives a carrier wave from the external transmission / reception device 10.

  The voltage generator 23 includes a rectifier diode D3, a smoothing capacitor C3, and a Zener diode ZD. The voltage generation unit 23 generates a drive voltage that drives each block in the wireless transmission device 20 using the AC voltage generated in the transmission / reception unit 22. Specifically, when an AC voltage generated in the transmission / reception unit 22 is input to the voltage generation unit 23, the rectifier diode D3 and the smoothing capacitor C3 rectify the AC voltage to generate a DC voltage. Further, the Zener diode ZD limits the voltage level of the DC voltage so that the DC voltage generated by the rectifier diode D3 and the smoothing capacitor C2 becomes a predetermined level. Zener diode ZD suppresses the voltage level so that the voltage level of the DC voltage is lower than the upper limit level when the voltage level is higher than a predetermined upper limit level. In this way, a drive voltage is generated, and each block in the wireless transmission device 20 is driven. In addition, the voltage level of the drive voltage can be kept within a predetermined range, and each block can be prevented from being destroyed due to the voltage being too high.

  The decoding unit 24 demodulates and decodes the transmission signal received by the transmission / reception unit 22 to generate transmission information.

  The signal state detection unit 25 detects the reception state of the transmission signal received by the transmission / reception unit 22 (the reception level of the transmission signal, the number of error locations in the transmission signal).

  The control unit 26 determines that “there is reception” when the reception state of the transmission signal detected by the signal state detection unit satisfies a predetermined condition, and obtains the communication distance based on the transmission level of the transmission signal. Here, the control unit 26 detects distance information from the transmission information generated by the decoding unit 24. Further, the control unit 26 has a level information correspondence table indicating a correspondence relationship between the transmission level of the transmission signal and the communication distance, and corresponds to the amplitude level indicated in the detected level information when it is determined that “reception is present”. The communication distance to be selected is selected from the level information correspondence table.

  In addition, the control unit 26 reads the ID information stored in the storage unit 21 in accordance with the reply command information included in the transmission information generated by the decoding unit 24. Further, the control unit 26 outputs reply information including distance information indicating the obtained communication distance and ID information read from the storage unit 21.

  The reply signal supply unit 27 generates a component (reply signal) to be superimposed on the carrier wave based on the reply information generated by the control unit 26, and supplies the generated component to the transmission / reception unit 22.

  In the transmission / reception unit 22, the switch SW is turned on / off according to the return signal from the return signal supply unit 27. When the switch SW is turned on / off, the impedance of the transmission / reception unit 22 changes, and the carrier wave is load-modulated in the transmission / reception unit 22. Thereby, a component corresponding to the reply signal is superimposed on the carrier wave. That is, the transmission / reception unit 22 transmits a reply signal.

  In the wireless transmission device 20, even when the reception state of the transmission signal does not satisfy the predetermined condition, the decoding unit 24 performs demodulation / decoding of the transmission signal and the control unit 26 acquires the transmission information. Of course, it is possible. Here, “sensing reception of a transmission signal” or “received” means that “the reception state of the transmission signal satisfies a predetermined condition”, and “demodulates and decodes the transmission signal. It doesn't mean that you can't.

<Level information correspondence table>
FIG. 9 shows an example of the level information correspondence table. The level information correspondence table shows the correspondence between “transmission level of transmission signal” and “communication distance” when the reception state of the transmission signal sensed by the wireless transmission device 20 is fixed. Here, the case where the reception state of the transmission signal is fixed means, for example, the case where the reception level of the transmission signal is a fixed level, or the case where the number of error locations in the transmission signal is a fixed number. In the level information correspondence table, the higher the amplitude level, the longer the communication distance corresponding to that amplitude level.

The level information correspondence table is created, for example, according to the following procedure.
[Step 1]: A desired condition (for example, a desired reception level of the transmission signal) to be satisfied by the reception state of the transmission signal in the wireless transmission device 20 is determined.
[Step 2]: The amplitude level of the transmission signal transmitted from the external transmission / reception device 10 (transmission level of the transmission signal) is set.
[Step 3]: The reception state of the transmission signal in the wireless transmission device 20 (for example, the reception level of the transmission signal in the wireless transmission device 20) is monitored while adjusting the communication distance.
[Step 4]: The communication distance when the reception state of the transmission signal in the wireless transmission device 20 satisfies the desired condition determined in [Step 1] is associated with the transmission level of the transmission signal set in [Step 2].

<< Internal Configuration of Decoding Unit >>
FIG. 10 shows an internal configuration of the decoding unit 24 and the signal state detection unit 25 shown in FIG. The decoding unit 24 includes a demodulation circuit 201, an error correction circuit 202, and a decoding processing unit 203. The signal state detection unit 25 includes a reception level measurement unit 204 and an error location counting circuit 205.

  The demodulation circuit 201 demodulates the transmission signal received by the transmission / reception unit 22 to generate transmission data. Note that a header and an error correction code are added to the transmission data.

  The error correction circuit 202 uses the error correction code added to the transmission data generated by the demodulation circuit 201 to perform error correction processing on the transmission data.

  The decoding processing unit 203 decodes the transmission data that has been corrected by the error correction circuit 202, and generates transmission information. Here, the transmission information includes reply command information and level information. The transmission information is supplied to the control unit 26.

  The reception level measurement unit 204 measures the amplitude level (transmission signal reception level) of the transmission signal received by the transmission / reception unit 22.

  The error location counter circuit 205 counts the number of error locations that have occurred in the transmission data for which error correction processing is executed in the error correction circuit 202.

<< Internal Configuration of Reply Signal Supply Unit >>
FIG. 11 shows an internal configuration of the reply signal supply unit 27 shown in FIG. The reply signal supply unit 27 includes an encoding processing unit 206, an error correction code addition unit 207, a reply data generation unit 208, and a modulation circuit 209.

  The encoding processing unit 206 encodes the reply information from the control unit 26 and generates reply data.

  The error correction code adding unit 207 performs a predetermined operation on the reply data generated by the encoding processing unit 206 to generate an error correction code. Then, error correction code adding section 207 adds the generated error correction code to the reply data.

  The reply data generation unit 208 adds a header to the reply data from the error correction code adding unit 207 (reply data to which the error correction code is added). The header includes a synchronization signal and a communication start identifier.

  The modulation circuit 209 turns on / off the switch SW of the transmission / reception unit 22 based on the reply data. For example, the switch SW is turned on when the output from the modulation circuit 209 is “H level”, and turned off when the output from the modulation circuit 209 is “L level”. Here, the modulation circuit 209 turns on / off the switch SW of the transmission / reception unit 22 at a specific frequency (for example, a subcarrier) during a period in which the data value of the return data from the return data generation unit 208 is “1”. The switch SW is turned off during the period when the data value of the reply data is “0”. That is, the modulation circuit 209 modulates a subcarrier (here, 212 kHz (= 13.56 MHz / 64)) based on the return data, and supplies the modulated subcarrier to the switch SW of the transmission / reception unit 22 as a return signal. The subcarrier is generated by, for example, a subcarrier generation unit (not shown) in the wireless transmission device 20. The subcarrier generation unit generates a clock signal from the carrier wave received by the transmission / reception unit 22, and generates a subcarrier by dividing the clock signal.

  For example, as shown in FIGS. 12A to 12C, in the wireless transmission device 20, the subcarrier (FIG. 12A) is modulated based on the return data (FIG. 12B) to become a modulated subcarrier (FIG. 12C). Also, as shown in FIGS. 12D and 12E, the carrier SW (FIG. 12D) is load-modulated by turning on / off the switch SW of the transmission / reception unit 22 according to the modulation subcarrier, and the component corresponding to the modulation subcarrier is the carrier (FIG. 12E). In the external transmission / reception device 10, the component corresponding to the modulation subcarrier is extracted as shown in FIG. 12F.

<Operation>
Next, the operation of the transmission / reception system according to the present embodiment will be described. Here, it is assumed that the control unit 11 increases the amplitude level indicated in the level information step by step from “Level 1”. That is, when the output of the level information indicating the amplitude level “Level 1” is completed, the control unit 11 outputs the level information indicating the amplitude level “Level 2”.

  First, in the external transmission / reception device 10, the control unit 11 outputs level information indicating the amplitude level “Level1” to the level setting unit 14 and supplies transmission information including level information indicating the amplitude level “Level1” as a transmission signal. To the unit 12. The level setting unit 14 sets the transmission level of the transmission signal in the transmission / reception unit 13 to “Level 1”. On the other hand, the transmission signal supply unit 12 supplies a transmission signal corresponding to transmission information including level information indicating the amplitude level “Level 1”. Thereby, the transmission / reception unit 13 transmits a transmission signal including level information (Level 1) and having an amplitude level of “Level 1”. When the transmission of the transmission signal from the transmission signal supply unit 12 is completed, the control unit 11 causes the transmission signal supply unit 12 to supply a constant amplitude carrier wave.

  Next, when the supply of the constant amplitude carrier wave by the transmission signal supply unit 12 is completed, the control unit 11 updates the amplitude level indicated in the level information from “Level 1” to “Level 2”. Thereby, the transmission signal supply unit 12 supplies a transmission signal corresponding to the transmission information including the level information indicating the amplitude level “Level 2”, and the level setting unit 14 transmits the transmission level of the transmission signal transmitted from the transmission / reception unit 13. Is updated to “Level 2”. Accordingly, the transmission / reception unit 13 transmits a transmission signal including level information indicating the amplitude level “Level 2” and having the amplitude level “Level 2”. When the transmission of the transmission signal from the transmission signal supply unit 12 is completed, the control unit 11 causes the transmission signal supply unit 12 to supply a constant amplitude carrier wave.

  In this way, transmission of transmission signals is repeated, and a plurality of transmission signals having different amplitude levels are sequentially transmitted. The amplitude level of each of the plurality of transmission signals is the amplitude level indicated in the level information included in the transmission signal.

  On the other hand, in the wireless transmission device 20, the signal state detection unit 25 detects the reception state of the transmission signal received by the transmission / reception unit 22. Specifically, the reception level measuring unit 204 measures the reception level of the transmission signal, and the error location counting circuit 205 counts error locations in the transmission signal. The transmission signal received by the transmission / reception unit 22 is processed by the decoding unit 24 to become transmission information.

  Here, the control unit 26 determines that the reception state of the transmission signal detected by the signal state detection unit 25 satisfies a predetermined condition (for example, the reception state set as a desired condition when creating the level information correspondence table). Then, it is determined that “there is reception”. For example, when the reception level measured by the reception level measurement unit 204 is higher than a predetermined level, the control unit 26 determines that the reception state of the transmission signal satisfies a predetermined condition. For example, when the number of error locations counted by the error location counting circuit 205 is smaller than a predetermined number, the control unit 26 determines that the reception state of the transmission signal satisfies a predetermined condition.

  If it is determined that “reception is present”, the control unit 26 selects a communication distance corresponding to the amplitude level indicated in the level information included in the transmission information from the level information correspondence table. Moreover, the control part 26 reads ID information memorize | stored in the memory | storage part 21 according to the reply command information contained in transmission information. Next, the control unit 26 writes the obtained communication distance and the read ID information in the reply information, and outputs the reply information to the reply signal supply unit 27. The reply information is processed by the reply signal supply unit 27 to become a reply signal, and a reply signal including distance information and ID information is transmitted by load modulation in the transmission / reception unit 22.

  Next, in the external transmission / reception device 10, the reply signal received by the transmission / reception unit 13 is processed by the decoding unit 15 to become reply information. The decoding unit 15 detects ID information and distance information from the reply information. Next, the control unit 11 acquires the ID information and the distance information detected by the decoding unit 15 and writes the ID information and the communication distance obtained in the wireless transmission device 20 in the measurement result information. Next, the control unit 11 outputs measurement result information to the host computer. Thereby, the host computer can grasp the distance between the external transmission / reception device 10 and the wireless transmission device 20.

<< Communication distance calculation >>
For example, when the control unit 26 of the wireless transmission device 20 determines that “there is reception” for the first time when a transmission signal including level information indicating the amplitude level “Level 2” is received, the amplitude level “ The communication distance “D2” corresponding to “Level2” is selected. Since the amplitude level of a transmission signal (for example, a transmission signal including level information indicating the amplitude level “Level 3”) transmitted subsequently to this transmission signal is increased step by step, the control unit 26 “receives”. Will be judged. However, here, it is only necessary to obtain level information when it is first determined that “reception is present”, and therefore, subsequent transmission signals need not be processed.

<< About reception determination >>
Moreover, in the external transmission / reception apparatus 10, the control part 11 may determine the presence or absence of reception of a reply signal based on the presence or absence of detection of ID information. In this case, the control unit 11 determines “received” when the ID information is detected, and does not determine “received” when the ID information is not detected. In this way, by determining whether or not a return signal is received based on whether or not ID information is detected, the communication distance to a specific wireless transmission device can be obtained even if a plurality of wireless transmission devices 20 are present. Can do. Further, after transmitting transmission signals sequentially to a plurality of wireless transmission devices and receiving reply signals from all the wireless transmission devices, obtaining a communication distance with each of the plurality of wireless transmission devices Is also possible.

<Effect>
As described above, the communication distance can be obtained based on the transmission level of the transmission signal, and the location of the wireless transmission device can be detected. In addition, the communication distance can be obtained and information stored in the wireless transmission device can be acquired.

  In the present embodiment, the case where the amplitude level indicated in the level information increases step by step each time a transmission signal is transmitted has been described. However, even when the amplitude level decreases step by step, the communication distance is obtained. It is possible. In this case, the control unit 26 may obtain the communication distance based on the level information included in the transmission signal that is finally determined to be “received”.

  The relationship between the transmission level of the transmission signal and the communication distance can be expressed as a mathematical expression. Accordingly, the control unit 26 performs a predetermined calculation based on the relationship between the transmission level of the transmission signal and the communication distance on the level information included in the transmission signal without using the level information correspondence table, thereby enabling communication. The distance may be calculated.

Furthermore, information other than the ID information (for example, information on a product to which the wireless transmission device is attached) may be written in the storage unit 21 of the wireless transmission device 20.
(Modification of load modulation method)
Note that the component superimposed on the carrier wave may be reply data instead of the subcarrier modulated based on the reply data. In this case, the modulation circuit 209 outputs the reply data from the reply data generation unit 208 to the switch SW of the transmission / reception unit 22 at a predetermined transfer rate (transfer rate corresponding to the frequency of the subcarrier). The modulation circuit 209 turns on the switch SW in a section where the data value of the reply data is “1”, and turns off the switch SW in a section where the data value of the reply data is “0”. That is, in this case, the modulation circuit 209 supplies the return data as a return signal to the switch SW of the transmission / reception unit 22.

  For example, as shown in FIGS. 13A and 13B, in the wireless transmission device 20, the modulation circuit 209 outputs reply data to the switch SW of the transmission / reception unit 22 based on the frequency of the subcarrier. Further, as shown in FIGS. 13C and 13D, the switch SW of the transmission / reception unit 22 is turned on / off according to the reply data, so that the carrier wave is load-modulated, and the component corresponding to the reply data is superimposed on the constant amplitude carrier wave. . In the external transmission / reception device 10, a component corresponding to the reply data is extracted as shown in FIG. 13E.

(Modification 1 of the first embodiment)
6A to 6D, when a transmission signal is supplied by modulating a carrier wave, a section corresponding to the data value “1” and a section corresponding to the data value “0” are uniformly distributed in the transmission signal. If it is biased to one side, the number of occurrences of switching of the amplitude level decreases, and it becomes difficult to recognize whether the amplitude level of the transmission signal is high or low. In this case, the reception level measurement unit 204 of the signal state detection unit 25 cannot accurately detect the reception level of the transmission signal, and it is difficult for the control unit 26 to accurately determine whether or not the transmission signal is received. Become.

<Configuration>
In the transmission / reception system according to the first modification of the first embodiment, the operation by the transmission signal supply unit 12 (see FIG. 4) of the external transmission / reception apparatus 10 is different. In the first modification, the transmission signal supply unit 12 multiplies transmission data by an M-sequence code when supplying a transmission signal based on transmission information. The M-sequence code is a data string in which a data value “1” and a data value “0” are randomly generated. Specifically, the transmission data generation unit 103 (see FIG. 5) multiplies transmission data to which a header and an error correction code are added by an M-sequence code. The M-sequence code is used to make the occurrence probability of each of the data values “1” and “0” uniform in the entire transmission data.

<Operation>
Next, the operation of the transmission / reception system according to the first modification will be described with reference to FIGS. 14A to 14E. Here, processing from generation of a transmission signal to reception determination of the transmission signal will be described.

  The transmission data generation unit 103 of the external transmission / reception device 10 multiplies the transmission data (FIG. 14B) to which the header and the error correction code are added by the M-sequence code. In the section of the transmission data multiplied by the M-sequence code, the occurrence probability of each of the data value “1” and the data value “0” is uniform (FIG. 14C). On the other hand, the transmission level of the transmission signal is set to the amplitude level indicated by the level information (FIG. 14D). A transmission signal is supplied by modulating a carrier wave (FIG. 14A) based on transmission data multiplied by an M-sequence code. In the section of the transmission signal multiplied by the M-sequence code, the section corresponding to the data value “1” and the section corresponding to the data value “0” are uniformly distributed (FIG. 14E). Since the amplitude level is continuously switched in the section of the transmission signal multiplied by the M-sequence code, the reception level measuring unit 204 can accurately measure the reception level of the transmission signal, and the control unit 26 is accurate. Whether or not a transmission signal is received can be determined based on the reception level.

  In addition, the demodulation circuit 201 performs an operation for removing the M-sequence code when demodulating the transmission signal received by the transmission / reception unit 22. That is, the demodulation circuit 201 demodulates the transmission signal to generate transmission data, and then multiplies the transmission data by the reciprocal of the M-sequence code.

<Effect>
As described above, the transmission signal is accurately measured at the reception level by providing the transmission signal with the section in which the section corresponding to the data value “1” and the section corresponding to the data value “0” are uniformly distributed. Can be secured. In this section, it is also possible to accurately count error locations in the transmission signal. Thereby, it is possible to accurately determine whether or not the reception state of the transmission signal satisfies a predetermined condition.

  14C illustrates an example in which the data values “1” and “0” are generated alternately and continuously in order to help understanding of the present embodiment, the data values “1” and “0” are illustrated. "May occur irregularly (may occur randomly). That is, the number of data values “1” and the number of data values “0” are equal (or substantially equal) within the section multiplied by the M-sequence code. In general, there are more examples in which the data values “1” and “0” are irregularly generated.

(Second Embodiment)
<Configuration>
The transmission / reception system according to the second embodiment of the present invention has the same configuration as that of the transmission / reception system according to the first embodiment, but the processing by the control unit 11 of the external transmission / reception device 10 and the control unit 26 of the wireless transmission device 20. Is different.

  In the transmission / reception system according to the present embodiment, the external transmission / reception device 10 sequentially updates the amplitude level indicated in the level information in accordance with a predetermined timing. That is, the external transmission / reception device 10 sequentially transmits a plurality of transmission signals having different amplitude levels according to a predetermined timing. Here, the transmission signal may not include level information.

  The wireless transmission device 20 manages the elapsed time after receiving the transmission signal. Further, the wireless transmission device 20 grasps in advance the timing at which the transmission level of the transmission signal is updated in the external transmission / reception device 10 and is based on the elapsed time when the reception state of the transmission signal satisfies a predetermined condition. To obtain the communication distance.

<External transmission / reception device 10>
The control unit 11 measures the elapsed time from the time when the first transmission signal is transmitted by the transmission / reception unit 13, outputs transmission information, and outputs level information indicating an amplitude level corresponding to the elapsed time. Specifically, the control unit 11 outputs first transmission information and first level information and starts measuring elapsed time. Further, the control unit 11 has a time amplitude level correspondence table indicating a correspondence relationship between the elapsed time and the transmission level of the transmission signal, and sequentially updates the amplitude level indicated in the level information according to the elapsed time. Here, the transmission information may not include level information.

<Wireless transmission apparatus 20>
The control unit 26 measures the elapsed time from the time when the first transmission signal is received, and obtains the communication distance based on the elapsed time when the reception of the transmission signal is sensed (when it is determined that “reception has occurred”). . Specifically, when receiving the reply command information included in the transmission information generated by the decoding unit 24, the control unit 26 starts counting elapsed time. Further, the control unit 26 includes a time amplitude level correspondence table and an amplitude level distance correspondence table indicating a correspondence relationship between the transmission level of the transmission signal and the communication distance, and the signal of the transmission signal detected by the signal state detection unit 25. If the state satisfies a predetermined condition, it is determined that “reception is present”, and the communication distance is obtained based on the elapsed time when it is determined that “reception is present”.

<Time amplitude level correspondence table>
FIG. 15A shows an example of a time amplitude level correspondence table. In the time amplitude level correspondence table, the time zone of the elapsed time and the transmission level of the transmission signal transmitted from the external transmission / reception device 10 in the time zone are associated one-to-one. The control unit 11 can grasp the transmission level to be set by referring to the time amplitude level correspondence table. Further, the control unit 26 can grasp the transmission level of the transmission signal transmitted from the external transmission / reception device 10 by referring to the time amplitude level correspondence table.

<Amplitude level distance correspondence table>
FIG. 15B shows an example of an amplitude level distance correspondence table. The amplitude level distance correspondence table shows the correspondence between the transmission level of the transmission signal and the communication distance when the reception state of the transmission signal sensed by the wireless transmission device 20 is fixed. The amplitude level distance correspondence table is created in the same procedure as the level information correspondence table, for example.

<Operation>
The operation of the transmission / reception system of this embodiment will be described with reference to FIG. 16A. Here, an example will be described in which the transmission level of the transmission signal increases step by step. In FIG. 16A, in order to make the wireless transmission device 20 recognize the reception of the first transmission signal with certainty, a communication start signal (wireless transmission device) that notifies the start of communication before transmitting the first transmission signal. Although a carrier wave (for example, a carrier wave having a maximum level) that reliably drives 20 is transmitted, a communication start signal is not essential in the present system. For example, even if the communication distance is maximum, the wireless transmission device 20 can be driven by using the first transmission signal (transmission signal having the minimum transmission level) as a power source, and the transmission information (reply command information) is decoded from the first transmission signal. If the transmission level of the first transmission signal is set so that it can be performed, the wireless transmission device 20 can time the elapsed time in synchronization with the time measurement of the elapsed time in the external transmission / reception device 10, A communication start signal is not necessary.

  First, when communication is started, in the external transmission / reception device 10, the control unit 11 starts transmission information including level information indicating the amplitude level “Level 1” and reply command information, and starts measuring time elapsed. To do. The transmission signal supply unit 12 supplies a transmission signal corresponding to the transmission information. The level setting unit 14 sets the transmission level of the transmission signal in the transmission / reception unit 13 to “Level 1”. The transmission / reception unit 13 transmits a transmission signal whose amplitude level is “Level 1”. On the other hand, in the wireless transmission device 20, the decoding unit 24 processes the transmission signal received by the transmission / reception unit 22 to generate transmission information. The control unit 11 reads the ID information from the storage unit 21 according to the reply command information included in the transmission information and starts measuring elapsed time.

  Between the elapsed times T0 and T1, the transmission / reception unit 13 transmits a transmission signal whose amplitude level is “Level 1”. When the transmission signal supply unit 12 completes the supply of the transmission signal (Level 1), the control unit 11 causes the transmission signal supply unit 12 to supply a constant amplitude carrier wave for a predetermined period.

  At the elapsed time T1, the control unit 11 selects the amplitude level “Level 2” corresponding to the time zones T1 to T2 from the time amplitude level correspondence table. Then, the control unit 11 stops outputting level information indicating the amplitude level “Level 1” and starts outputting level information indicating the amplitude level “Level 2”. The level setting unit 14 sets the resistance value of the variable resistor R1 so that the transmission level of the transmission signal becomes “Level 2”. Accordingly, the transmission / reception unit 13 transmits a transmission signal having an amplitude level of “Level 2”. When the transmission of the transmission signal whose amplitude level is “Level 2” is completed between the elapsed times T1 and T2, a constant amplitude carrier wave is transmitted for a predetermined period.

  At the elapsed times T2 and T3, similarly to the elapsed time T1, the control unit 11 executes the selection of the amplitude level from the time amplitude level correspondence table, the update of the level information, and the re-output of the transmission information. Therefore, transmission of a transmission signal whose amplitude level is “Level 3” is started at the elapsed time T2, and transmission of a transmission signal whose amplitude level is “Level 4” is started at the elapsed time T3. Thus, the transmission level of the transmission signal is sequentially updated according to the elapsed time.

  On the other hand, in the wireless transmission device 20, the control unit 26 determines whether or not a transmission signal is received, as in the first embodiment. If it is determined that “reception is present” between the elapsed times T1 and T2, the control unit 26 selects the amplitude level “Level2” corresponding to the current elapsed time from the time amplitude level correspondence table. Next, the control unit 26 selects the communication distance “D2” corresponding to the selected amplitude level “Level2” from the amplitude level distance correspondence table. Then, the control unit 26 outputs reply information including distance information indicating the obtained communication distance and ID information read from the storage unit 21. The reply information is processed by the reply signal supply unit 27 to become a reply signal, and the transmission / reception unit 22 transmits the reply signal.

  Next, in the external transmission / reception device 10, as in the first embodiment, the reply signal received by the transmission / reception unit 13 is processed by the decryption unit 15 to become reply information. Information is detected. The control unit 11 writes the detected distance information and ID information in the measurement result information, and outputs the measurement result information to the host computer.

<Effect>
As described above, the communication distance can be obtained by managing the elapsed time, and the presence position of the wireless transmission device can be detected. In addition, the communication distance can be obtained and information stored in the wireless transmission device can be acquired.

  When the communication start signal includes reply command information, the control unit 26 can start counting elapsed time based on the reply command information included in the communication start signal. The instruction information may not be included.

  In addition, as illustrated in FIG. 16B, an example in which the transmission level of the transmission signal is decreased by one step can be realized. In this case, the control unit 26 of the wireless transmission device 20 may obtain the communication distance based on the elapsed time when it is finally determined that “reception is present”. Further, even if the communication distance is maximum, the wireless transmission device 20 is driven by using the first transmission signal (in this case, the transmission signal having the maximum transmission level) as a power source, and transmission information (reply command information) If the transmission level of the first transmission signal is set so that it can be decoded, the communication start signal is unnecessary.

  Further, even when the communication start signal is not used, if the reply command information is included in the first transmission signal, the control unit 26 starts measuring the elapsed time based on the reply command information included in the transmission signal. Therefore, the reply command information does not have to be included in the transmission signal transmitted after the second time.

  Further, as shown in FIG. 17, by combining the time amplitude level correspondence table (FIG. 15A) and the amplitude level distance correspondence table (FIG. 15B), the wireless transmission device 20 that can create the time distance correspondence table. The control unit 26 may include a time distance correspondence table instead of the time amplitude level correspondence table and the amplitude level distance correspondence table. According to this, the number of stored tables can be reduced, and the time required for obtaining the communication distance can be shortened.

  Further, similarly to the first embodiment, the modification example and modification example 1 of the load modulation method can be applied to the second embodiment.

(Third embodiment)
<Configuration>
The transmission / reception system according to the third embodiment of the present invention has the same configuration as that of the transmission / reception system according to the first embodiment, but processing by the control unit 11 of the external transmission / reception device 10 and the control unit 26 of the wireless transmission device 20. Is different.

  In the transmission / reception system according to the present embodiment, the external transmission / reception device 10 sequentially updates the amplitude level indicated in the level information in accordance with the number of transmissions of the transmission signal. That is, the external transmission / reception device 10 sequentially transmits a plurality of transmission signals having different amplitude levels according to the number of transmissions of the transmission signal. Here, the transmission signal may not include level information.

  The wireless transmission device 20 counts the number of times of transmission signal reception. Further, the wireless transmission device 20 knows in advance the relationship between the number of transmissions of the transmission signal and the transmission level of the transmission signal in the external transmission / reception device 10, and when the reception state of the transmission signal satisfies a predetermined condition The communication distance is obtained based on the number of receptions.

<External transmission / reception device>
The control unit 11 counts the number of transmissions of the transmission signal by the transmission / reception unit 13, outputs transmission information, and outputs level information indicating an amplitude level corresponding to the number of transmissions. Specifically, the control unit 11 counts the number of times level information is output as the number of transmissions of the transmission signal. In addition, the control unit 11 has a transmission frequency amplitude level correspondence table indicating a correspondence relationship between the transmission frequency of the transmission signal and the transmission level of the transmission signal, and sequentially updates the amplitude level indicated in the level information according to the transmission frequency. To do. Here, the transmission information may not include level information.

<Wireless transmission device>
The control unit 26 counts the number of receptions of the transmission signal by the transmission / reception unit 13 and obtains the communication distance based on the number of receptions when the reception of the transmission signal is sensed (when it is determined that “there is reception”). Specifically, the number of receptions of transmission information generated by the decoding unit 24 is counted as the number of receptions. In addition, the control unit 26 includes a transmission frequency amplitude level correspondence table and an amplitude level distance correspondence table. If the reception state of the transmission signal detected by the signal state detection unit 25 satisfies a predetermined condition, “reception is present”. And the communication distance is obtained based on the number of receptions when it is determined that “reception is present”.

<Transmission count amplitude level correspondence table>
FIG. 18 shows an example of a transmission count amplitude level correspondence table. In the transmission frequency amplitude level correspondence table, the number of transmissions of the transmission signal is associated with the transmission level of the transmission signal to be transmitted by the external transmission / reception device 10 at the time of the transmission. The control unit 11 can grasp the transmission level to be set by referring to the transmission frequency amplitude level correspondence table. Further, the control unit 26 can grasp the transmission level of the transmission signal transmitted from the external transmission / reception device 10 by referring to the transmission count amplitude level correspondence table.

<Operation>
The operation of the transmission / reception system of this embodiment will be described with reference to FIG. Here, an example will be described in which the transmission level of the transmission signal increases step by step. Further, in FIG. 19, in order to reliably recognize reception of a transmission signal in the wireless transmission device 20, before transmitting the transmission signal, a detection signal (a carrier wave (for example, a carrier that reliably drives the wireless transmission device 20) Although the maximum level carrier wave)) is transmitted, a detection signal is not essential in this system. For example, even if the communication distance is the maximum, the wireless transmission device 20 drives the first transmission signal (that is, the transmission signal having the minimum transmission level) as a power source, and transmits transmission information (reply command) from the first transmission signal. If the transmission level of the first transmission signal is set so that (information) can be decoded, each time the transmission signal is transmitted from the external transmission / reception device 10, the wireless transmission device 20 Since the reception can be recognized, the detection signal is unnecessary.

  First, when communication is started, in the external transmission / reception device 10, the control unit 11 selects an amplitude level “Level 1” corresponding to “first” from the transmission count amplitude level correspondence table. Next, the control unit 11 outputs transmission information including the first level information indicating the amplitude level “Level 1” and reply command information. The transmission signal supply unit 12 supplies a transmission signal corresponding to the transmission information. The level setting unit 14 sets the transmission level of the transmission signal to “Level 1”. Accordingly, the transmission / reception unit 13 transmits the first transmission signal whose amplitude level is “Level 1”. When the transmission of the first transmission signal is completed, a carrier wave having a constant amplitude is transmitted. On the other hand, in the wireless transmission device 20, the decoding unit 24 processes the transmission signal received by the transmission / reception unit 22 to generate transmission information, and the control unit 26 receives the generated transmission information and determines the number of transmission signals received. “First”.

  Next, in the external transmission / reception device 10, when the control unit 11 completes transmission of the carrier wave having a constant amplitude, the control unit 11 sets the amplitude level “Level2” corresponding to “second time” from the transmission frequency amplitude level correspondence table. ”Is selected. Next, the control unit 11 re-outputs the transmission information including the reply command information and updates the amplitude level indicated in the level information to “Level 2”. That is, the control unit 11 stops outputting the first level information (Level 1) and outputs the second level information (Level 2). The transmission signal supply unit 12 supplies the transmission signal corresponding to the transmission information again, and the level setting unit 14 sets the transmission level of the transmission signal to “Level 2”. Thereby, the transmission / reception unit 13 transmits the second transmission signal whose amplitude level is “Level 2”. On the other hand, in the wireless transmission device 20, the control unit 26 receives the transmission information generated by the decoding unit 24 and sets the number of receptions of the transmission signal to “second”.

  Thus, the transmission level of the transmission signal is sequentially updated according to the number of transmissions.

  On the other hand, in the wireless transmission device 20, the control unit 26 determines whether or not a transmission signal is received, as in the first embodiment. If it is determined that “reception is present” when the second transmission signal is received, the control unit 26 determines from the transmission frequency amplitude level correspondence table the amplitude level “Level2” corresponding to the current reception frequency “second”. ”Is selected. Next, the control unit 26 selects the communication distance “D2” corresponding to the selected amplitude level “Level2” from the amplitude level distance correspondence table. Then, the control unit 26 outputs reply information including distance information indicating the obtained communication distance and ID information read from the storage unit 21. The reply information is processed by the reply signal supply unit 27 to become a reply signal, and the transmission / reception unit 22 transmits the reply signal.

  Next, in the external transmission / reception device 10, as in the first embodiment, the reply signal received by the transmission / reception unit 13 is processed by the decryption unit 15 to become reply information. Information is detected. The control unit 11 writes the detected distance information and ID information in the measurement result information, and outputs the measurement result information to the host computer.

<Effect>
As described above, the communication distance can be obtained by managing the number of transmissions of the transmission signal, and the location of the wireless transmission device 20 can be detected. In addition, the communication distance can be obtained and information stored in the wireless transmission device can be acquired.

  An example in which the transmission level of the transmission signal is reduced step by step can be realized. In this case, the control unit 26 of the wireless transmission device 20 may obtain the communication distance based on the number of times of reception when it is finally determined that “reception is present”. Further, even when the communication distance is maximum, the transmission signal transmitted by the wireless transmission device 20 last (that is, the transmission signal having the minimum transmission level) is driven as a power source, and transmission information ( If the transmission level of the transmission signal is set so that the reply command information) can be decoded, the wireless transmission device 20 transmits the transmission signal each time the transmission signal is transmitted from the external transmission / reception device 10. Since the reception can be recognized, the detection signal is unnecessary.

  Further, as shown in FIG. 20, a transmission count distance correspondence table can be created by combining the transmission count amplitude level correspondence table (FIG. 18) and the amplitude level distance correspondence table (FIG. 15B). The control unit 26 of the wireless transmission device 20 may include a transmission frequency distance correspondence table instead of the transmission frequency amplitude level correspondence table and the amplitude level distance correspondence table. According to this, the number of stored tables can be reduced, and the time required for obtaining the communication distance can be shortened.

  Further, similarly to the first embodiment, the modification example and the modification example 1 of the load modulation method are applicable to the third embodiment.

  In the description of the above embodiment, while the external transmission / reception device 10 completes transmission of a transmission signal and transmits a carrier wave having a constant amplitude (that is, the operation mode of the external transmission / reception device 10 is “read operation”). While a reply signal is returned by carrier load modulation during a certain period of time, it is also possible to perform carrier load modulation during a period in which the amplitude level of the carrier from the external transmission / reception device 10 is not constant. For example, while a transmission signal is being transmitted, a return signal can be transmitted by load-modulating the transmission signal. In this case, it is not necessary to transmit a carrier wave for receiving a reply signal (a constant amplitude carrier wave is not necessary). In this way, the external transmission / reception device 10 can simultaneously execute both the “write operation” and the “read operation”. According to this, the time required for communication can be shortened. This method in which both the “write operation” and the “read operation” are performed simultaneously is very effective for shortening the time for one-to-multiple communication, not one-to-one communication.

(Application example 1)
<Configuration>
FIG. 21 shows a configuration of a container management system to which the transmission / reception system according to the first embodiment is applied. The container management system includes an external transmission / reception device 10, a wireless transmission device 20, a storage container 30, and a display device 40. This system manages the contents (liquid) stored in the storage container 30.

[Container 30]
The storage container 30 includes a container body 301 and a floating member 302.

  The container main body 301 has, for example, a shape with a constant cross-sectional area (for example, a cubic shape, a rectangular parallelepiped shape, a cylindrical shape, etc.) and accommodates a liquid.

  The floating member 302 is a plate-like member having a size of several millimeters square, and is floating on the liquid surface of the liquid stored in the container main body 301. The floating member 302 is made of a material having a lower density or specific gravity than the liquid stored in the storage container 301. However, since the floating member 302 only needs to float on the surface of the liquid, the density of the floating member 302 does not need to be lighter than the liquid density. If the surface tension can float on the liquid surface, the density of the floating member 302 is low. It may be heavier than the liquid density. The floating member 302 moves up and down in accordance with an increase or decrease in the internal volume of the liquid stored in the container body 301.

  The wireless transmission device 20 is installed on the surface of the floating member 302.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is arranged at a position corresponding to the moving direction of the floating member 302 as a loop-shaped transmission / reception antenna. Here, the transmission / reception coil L1 is disposed on the upper portion of the container 30 located on the extension line in the moving direction of the floating member 302.

  Further, the control unit 11 of the external transmission / reception device 10 calculates the internal volume of the liquid stored in the storage container 30 based on the communication distance indicated by the distance information detected from the reply signal by the decoding unit 15. To do. The “distance D1 from the external transmission / reception device 10 to the bottom surface of the container body 301” and the “bottom area S1 of the container body 301” are constant, and the control unit 11 stores these values in advance. In addition, the control unit 11 outputs management information in which the detected ID information and the obtained liquid volume are written instead of the measurement result information to the display device 40.

[Display device 40]
The display device 40 displays management information (ID information, liquid content) from the external transmission / reception device 10.

[Wireless transmission apparatus 20]
FIG. 22 shows an installation example of the wireless transmission device 20 in the floating member 302. The wireless transmission device 20 is formed as an IC chip, for example, and is installed on the surface of the floating member 302 of the container 30. The transmission / reception coil L2 of the wireless transmission device 20 is arranged as a looped transmission / reception antenna. Here, if the entire surface of the floating member 302 is subjected to a waterproof treatment or a water repellent treatment, not only the IC chip can be protected but also the floating property can be improved.

<Operation>
Next, the operation of the container management system shown in FIG. 21 will be described.

  First, various signals (a transmission signal and a reply signal) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and the control unit 11 of the external transmission / reception device 10 is obtained by the wireless transmission device 20. The obtained communication distance D2 is acquired.

  Next, the control unit 11 subtracts the “communication distance D2” from the “distance D1” stored therein in advance to obtain the “distance (liquid level) D3 from the bottom surface of the container body 301 to the liquid surface”. calculate. Next, the control unit 11 calculates the internal volume of the liquid stored in the storage container 30 by multiplying the calculated “liquid level D3” by the “bottom area S1 of the container main body 301”. Next, the control unit 11 writes the ID information detected by the information detection unit 109 and the calculated liquid volume in the management information, and outputs the management information to the display device 40.

  Next, the display device 40 displays management information (ID information, liquid content) from the external transmission / reception device 10.

  Here, as shown in FIG. 23, when the internal volume of the liquid stored in the storage container 30 decreases, the floating member 302 in which the wireless transmission device 20 is installed descends. As a result, the distance between the external transmission / reception device 10 and the wireless transmission device 20 becomes long, so that the reception state of the transmission signal in the wireless transmission device 20 deteriorates (for example, the reception level of the transmission signal decreases). Therefore, compared with the case of FIG. 21, the communication distance D2 calculated | required by the wireless transmission apparatus 20 becomes long, and the calculated liquid content volume reduces. That is, the liquid content displayed on the display device 40 decreases.

<Effect>
As described above, the content of the contents stored in the storage container can be measured from the communication distance between the external transmission / reception device and the wireless transmission device. Moreover, the content accommodated in the storage container can be identified by acquiring the ID information. Thereby, the kind and content of the content accommodated in the storage container can be managed simultaneously.

  If the storage unit 21 of the wireless transmission device 20 stores the content information, the control unit 26 of the wireless transmission device 20 sends the content information together with the ID information to the return information (the source of the reply signal). It is also possible to write in the information). The content information is information about the content stored in the storage container 30 such as the type of content and the date of manufacture. In this case, if the content information is acquired together with the ID information by the information detection unit 109, the quality control can be performed simultaneously with the measurement of the liquid content.

  Further, the position where the transmission / reception coil L <b> 1 of the external transmission / reception device 10 is arranged is not limited to the upper part of the container 30. If the distance between the external transmission / reception device 10 and the wireless transmission device 20 is uniquely determined with respect to the change in the liquid level, the transmission / reception coil L1 of the external transmission / reception device 10 may be disposed beside the container 30. Absent.

  In this application example, the case where the cross-sectional area of the container main body 301 is constant is shown. However, if the relationship between the liquid level D3 and the volume of liquid contained is determined in advance, the cross-sectional area is not constant. May be.

<Installation location of IC tag>
As shown in FIG. 24, three wireless transmission devices 20-1, 20-2 and 20-3 may be arranged on the floating member 302. In this case, the external transmission / reception device 10 is based on the communication distance d1 with the wireless transmission device 20-1, the communication distance d2 with the wireless transmission device 20-2, and the communication distance d3 with the wireless transmission device 20-3. To measure the communication distance D2. According to this, even when the liquid level is inclined, the communication distance can be accurately measured. This is particularly effective when the container is attached to a portable electronic device.

(Variation 1 of the container)
In addition, as shown in FIG. 25, the same effect can be obtained when the storage container 30A is used instead of the storage container 30 shown in FIG. The storage container 30A includes a container main body 301A and a partition wall member 302A. The partition member 302A moves along the height direction of the container main body 301A according to the increase or decrease of the liquid stored in the container main body 301A. In addition, the transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the partition wall member 302A. Here, the transmission / reception coil L1 is disposed above the storage container 30A, which is an extension of the partition member 302A in the moving direction. Accordingly, the communication distance D2 can be measured even when the storage container 30A is tilted. Moreover, since airtightness can be ensured, it is possible to prevent the liquid as the contents from leaking to the outside or the outside air from entering the housing container 30A even when the housing container 30A is tilted.

(Variation 2 of the container)
Furthermore, as shown in FIG. 26, the same effect can be obtained when the storage container 30B is used instead of the storage container 30 shown in FIG. The storage container 30B expands and contracts in accordance with the increase and decrease of the internal volume of the liquid stored in itself (see FIG. 27). Here, the storage container 30B expands and contracts in the height direction. The wireless transmission device 20 is installed on the extended line in the expansion / contraction direction (here, the upper surface of the storage container 30B) on the surface of the storage container 30B. The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the expansion / contraction direction of the container 30B. Here, it arrange | positions above the container 30B which is on the extension line | wire of an expansion-contraction direction. According to this, even if the whole container management system inclines, the communication distance D2 can be measured. Further, since the wireless transmission device 20 is lightweight, the influence of the weight of the wireless transmission device 20 on the shape of the storage container 30B is small, and measurement errors can be reduced. Further, if the upper surface of the container 30B can be made substantially parallel to the external transmission / reception device 10, the communication distance D2 can be measured with high accuracy. Further, the storage container 30B may be entirely formed of the same members and materials, but the members and materials may be partially different. According to this, the degree of deformation in each part of the storage container 30B can be adjusted so that the upper surface of the storage container 30B is substantially parallel to the external transmission / reception device 10.

(Application example 2)
<Configuration>
FIG. 28 shows a configuration of a fuel cell system to which the transmission / reception system according to the first embodiment is applied. The fuel cell system includes a container 30, a wireless transmission device 20, a fuel cell unit 50, and an electronic device 60. In this system, the fuel cell unit 50 generates power using the aqueous methanol solution stored in the storage container 30 as fuel, and the electronic device 60 is driven by the power of the fuel cell unit 50 and manages the aqueous methanol solution stored in the storage container 30. . The electronic device 60 is, for example, a notebook personal computer.

[Container 30]
The storage container 30 stores a methanol aqueous solution. The storage unit 21 of the wireless transmission device 20 provided in the floating member 302 stores methanol information as content information in addition to the ID information. The methanol information is information relating to the aqueous methanol solution stored in the storage container 30, such as the concentration of the aqueous methanol solution. The reply signal includes methanol information in addition to the ID information.

[Fuel cell unit 50]
The fuel cell unit 50 includes a power generation unit 500 and an external transmission / reception device 10. The power generation unit 500 includes a fuel supply pump 501, a DMFC power generation cell 502, and a voltage conversion circuit 503.

  The fuel supply pump 501 sucks out the methanol aqueous solution from the container 30 and supplies the sucked methanol aqueous solution to the power generation cell 502. The power generation cell 502 generates power using the aqueous methanol solution supplied from the fuel supply pump 501. The voltage conversion circuit 503 converts the electric power generated by the power generation cell 502 into a voltage suitable for the electronic device 60 and supplies the converted electric power to the electronic device 60.

  The information detection unit 109 of the external transmission / reception device 10 detects methanol information in addition to the ID information.

  The control unit 11 calculates the internal volume of the aqueous methanol solution stored in the storage container 30 based on the acquired communication distance. In addition, the control unit 11 outputs management information in which the ID information and methanol information detected by the information detection unit 109 and the calculated content of the aqueous methanol solution are written to the electronic device 60 instead of the measurement result information. Further, the control unit 11 outputs a remaining amount decrease signal to the electronic device 60 when the content of the aqueous methanol solution stored in the storage container 30 becomes equal to or less than the specified amount.

[Electronic device 60]
The electronic device 60 includes a control microcomputer 601 and a display unit 602. The control microcomputer 601 receives management information from the external transmission / reception device 10 and outputs the management information to the display unit 602. Further, when the control microcomputer 601 receives the remaining amount decrease signal from the external transmission / reception device 10, it outputs a warning display command.

  The display unit 602 displays management information (ID information, methanol information, content of methanol aqueous solution) from the control microcomputer 601. Further, when receiving a warning display command from the control microcomputer 601, the display unit 602 displays a remaining amount reduction notification image. The remaining amount decrease notification image is an image for notifying that the remaining amount of the aqueous methanol solution is small, such as “the remaining amount of fuel“ low ””.

<Operation>
Next, the operation of the fuel cell system shown in FIG. 28 will be described.

  When the power generation operation by the fuel cell unit 50 is started, various signals (transmission signal, reply signal) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20 to control the external transmission / reception device 10. The unit 11 periodically acquires the communication distance D2. Further, the control unit 11 calculates the internal volume of the aqueous methanol solution stored in the storage container 30 based on the acquired communication distance. Next, the control unit 11 writes the ID information and methanol information detected by the information detection unit 109 and the obtained volume of the aqueous methanol solution in the management information, and periodically outputs the management information to the electronic device 60. Thereby, the management information (ID information, methanol information, content of methanol aqueous solution) displayed on the display unit 602 of the electronic device 60 is periodically updated.

  Further, when the control unit 11 determines that the calculated internal volume of the aqueous methanol solution is equal to or less than the specified amount, the control unit 11 outputs a remaining amount decrease signal to the control microcomputer 601. Therefore, “remaining amount“ low ”” is displayed on the display unit 602. Thereby, it is possible to prompt the user of the electronic device 60 to change the fuel or refill the fuel.

<Effect>
As described above, the content of the aqueous methanol solution can be measured from the communication distance between the external transmission / reception device and the wireless transmission device. Moreover, the methanol aqueous solution accommodated in the container can be identified by acquiring the methanol information. Thereby, the kind and content volume of methanol aqueous solution can be managed simultaneously.

  In addition, by referring to the methanol information as the contents information, it is possible to prevent erroneous use of aqueous methanol solutions having different specifications. In other words, the content information displayed on the display unit 602 can include information on conformity / nonconformity of the content with respect to the fuel cell system.

  Further, in the fuel cell system for electronic devices, the container 30 is relatively small. Here, since the floating member 302 provided with a wireless transmission device (for example, a wireless tag) can be manufactured with a size of about several millimeters square, it can also be used for a small container 30. That is, it can be applied to a small container.

  In addition, it is possible to replace conventional components for content management (liquid level measurement using the conductivity and dielectric constant of contents or reflection of ultrasonic waves) with a small and lightweight wireless transmission device. It becomes. As a result, fuel information of the fuel cell system (fuel concentration, characteristics of contents, number of cartridge recycles, etc.) can be stored, and at the same time, sharing as a component for managing the internal capacity can be realized. In this way, an excellent effect of reducing the size and weight of the storage container can be obtained. In addition, since the conventional components for the internal volume management method are not necessary, the space for storing the fuel can be increased. Thereby, prolonged operation of the fuel cell system can be realized.

  In addition, although methanol aqueous solution was mentioned as an example as a fuel, it is not restricted to methanol, Liquids, such as a solution which melt | dissolved borohydride in alkaline aqueous solution, can also be used as fuel instead of methanol.

  Further, information regarding the liquid level measured periodically may be stored in the external transmission / reception device 10 and the wireless transmission device 20. Further, the expected remaining driving time of the fuel cell system can be obtained from the stored liquid level information and the measured elapsed time.

  Moreover, it may replace with the storage container 30 shown in FIG. 28, and may provide the storage container shown in FIG.25 and FIG.26.

  The transmission / reception system can be applied not only to the fuel cell system but also to a system that is easily within the scope of those skilled in the art. For example, it can be used to store liquids, such as storage containers for petroleum fuel (for example, kerosene, gasoline), fuel tanks for automobiles, storage containers for edible seasonings, oil, soup, liquor, etc. It is. As a large one, it can be used in a crude oil storage tank having a floating lid.

  Further, the present invention can be applied to cases other than the case where the content is a liquid (for example, a case where a solid is stored like rice bran). In this case, as the container, for example, a form as shown in FIGS. 25 and 26 is preferable. Moreover, in the form shown in FIG.25 and FIG.26, even when the content is gas, it is applicable.

(Application example 3)
<Configuration>
FIG. 29 shows a configuration of an infusion management system to which the transmission / reception system according to the first embodiment is applied. The infusion management system includes an infusion pack 71, an infusion stand 72, a wireless transmission device 20, an external transmission / reception device 10, an information transmission device 73, and a display device 40. This infusion management system is applied to an infusion pack used for infusion at a medical site such as a hospital.

[Infusion pack 71]
The infusion pack 71 stores the infusion. A floating member 302 is floating on the liquid level of the infusion contained in the infusion pack 71.

[Infusion stand 72]
The infusion stand 72 includes a support column 72a that extends substantially vertically from the installation surface, and a pack attachment 72b that protrudes from the tip of the support column 72a. The infusion pack 71 is attached to the attachment hook of the pack attachment portion 72b.

[Wireless transmission apparatus 20]
The wireless transmission device 20 is installed on the surface of the floating member 302 that floats in the infusion pack 71. The storage unit 21 of the wireless transmission device 20 stores infusion information as content information in addition to the ID information. Infusion information is, for example, information on infusion, such as the type, concentration, volume, expiration date of use, information on infusion pack containers, etc. The reply signal includes infusion information in addition to the ID information.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the floating member 302 in a state where the infusion pack 71 is attached to the infusion stand 72. Here, the transmission / reception coil L1 is disposed on the pack attachment portion 72b of the infusion stand 72, which is on the extension line in the moving direction of the floating member 302.

  Moreover, the information detection part 109 of the external transmission / reception apparatus 10 detects infusion information in addition to ID information. The controller 11 calculates the internal volume of the infusion contained in the infusion pack 71 based on the acquired communication distance. The control unit 11 stores in advance a content correspondence table created based on the relationship between the communication distance and the content of the infusion. In the internal capacity correspondence table, a plurality of internal capacity and a plurality of communication distances are associated. In the internal capacity correspondence table, the internal capacity corresponding to the communication distance decreases as the communication distance increases. Instead of the measurement result information, the control unit 11 outputs the measurement result information in which the ID information and the infusion information detected by the information detection unit 109 and the calculated infusion volume are written to the information transmission device 73.

  Moreover, the control part 11 will output the residual amount reduction signal to the information transmission apparatus 73, if the content volume of infusion is below a regulation amount. Further, the control unit 11 stores in advance patient information, which is information related to the patient, such as the type of infusion to be administered to the patient, and the infusion information detected by the information detection unit 109 and the patient information stored in itself. If they do not match, a warning signal is output to the information transmission device 73.

[Information transmission device 73]
The information transmission device 73 transmits various signals (management information, remaining amount reduction signal, warning signal) from the external transmission / reception device 10 to the display device 40. Here, when the information transmission device 73 and the display device 40 communicate wirelessly, a frequency that does not interfere with the communication between the external transmission / reception device 10 and the wireless transmission device 20 may be employed. Communication between the information transmission device 73 and the display device 40 may be performed by wire.

[Display device 40]
The display device 40 is installed in a hospital room or a nurse station. The display device 40 displays management information (ID information, infusion information, infusion volume) from the information transmission device 73. Further, when the display device 40 receives the remaining amount reduction signal from the information transmission device 73, the display device 40 displays a remaining amount reduction notification image. In addition, when receiving a warning signal from the information transmission device 73, the display device 40 displays an infusion nonconformity notification image. The infusion solution non-conformity notification image is an image notifying that the infusion pack is not correctly assigned to the patient, for example, “infusion pack non-conformity”.

<Operation>
Next, the operation of the infusion management system shown in FIG. 29 will be described.

  When the infusion pack 71 is attached to the infusion stand 72, various signals (transmission signals, reply signals) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and the external transmission / reception device 10 is controlled. The unit 11 periodically acquires a communication distance. Moreover, the control part 11 calculates | requires the content volume of the infusion accommodated in the infusion pack 71 based on the acquired communication distance. For example, the control unit 11 detects the internal capacity corresponding to the communication distance from the internal capacity correspondence table stored in itself. Next, the control unit 11 writes the ID information and the infusion information detected by the information detection unit 109 and the obtained infusion volume in the management information, and periodically outputs the management information to the information transmission device 73.

  Next, the information transmission device 73 transmits the management information from the external transmission / reception device 10 to the display device 40. Thereby, the management information (ID information, infusion information, infusion volume) displayed on the display device 40 is periodically updated.

  Moreover, if the control part 11 of the external transmission / reception apparatus 10 determines with the content volume of the calculated | required infusion being below a regulation amount, it will output a residual amount reduction signal. Therefore, “remaining amount“ low ”” is displayed on the display device 40. Thereby, attention of drip exchange can be urged.

  Further, when the control unit 11 determines that the patient information stored in advance in itself does not match the infusion information detected by the information detection unit 109, the control unit 11 outputs a warning signal. Therefore, “not compatible with infusion pack” is displayed on the display device 40. Thereby, attention of drip incompatibility can be urged.

<Effect>
As described above, the type and content of the infusion contained in the infusion pack can be managed simultaneously. Moreover, since the remaining amount of the infusion pack assigned to each patient can be managed, the timing of infusion exchange for many patients can be grasped. In this case, the information transmission device 73 and the display device 40 may be wirelessly communicated, and the display device 40 may be carried by a nurse or a doctor as being small and portable. This frees nurses and doctors from the troublesome work associated with running out of infusion. Further, by referring to the infusion information as the contents information, it is possible to collate whether or not the infusion is suitable for the patient. Therefore, it is possible to prevent a medical error such as injecting the wrong infusion to the patient. In other words, the contents information displayed on the display device 40 can include information on conformity / nonconformity of the contents with respect to the infusion management system.

  Moreover, since the floating member 302 provided with the wireless transmission device can be manufactured with a size of about several millimeters square, it can also be used for a small infusion pack 71. That is, it can be applied to a small infusion pack.

  The display device 40 may emit a warning sound together with the remaining amount reduction notification image and the infusion nonconformity notification image. Moreover, you may provide the alarm device which emits a warning sound separately. In this application example, the display device 40 is installed in a hospital room, a nurse station, or the like, but may be attached to the information transmission device 73, the external transmission / reception device 10, the infusion stand 72, or the like. Furthermore, the information transmission device 73 and the external transmission / reception device 10 may be integrated.

  In this application example, the example using the internal capacity correspondence table is shown, but the internal capacity corresponding to the communication distance may be obtained using a calculation formula.

  Each device (external transmission / reception device 10, information transmission device 73, etc.) installed on the infusion stand 72 may be a type in which power is supplied from an outlet or a cordless type using a rechargeable battery. good.

  Furthermore, in this application example, an infusion pack used for infusion is given as an example, but the infusion in this application example includes blood. That is, the present invention can also be applied to a blood transfusion pack used for blood transfusion. In this case, if the storage unit 21 of the wireless transmission device 20 stores information related to blood type, it is possible to manage the remaining amount of blood for blood transfusion and blood type. As a result, similar to the infusion management system in this application example, it is possible to prevent a medical error such as transfusion of wrong blood to the patient. Further, the present system is not limited to medical use, and can be applied to an infusion management system using a liquid other than medical use.

  Alternatively, the wireless transmission device 20 may be suspended on the infusion surface of the infusion pack 71 in a state of being housed in a capsule using the same material as the material forming the infusion pack 71 instead of being installed on the floating member 302. good.

(Application example 4)
<Configuration>
Next, a paper management system to which the transmission / reception system according to the first embodiment is applied will be described. The paper management system manages printer paper stored in the printer.

  FIG. 30 is an external view of the printer 80. The paper management system includes an external transmission / reception device 10, a wireless transmission device 20, a paper feed tray 81, and a printer main body 82. A concave tray storage portion 800 is formed in the printer main body 82. The paper feed tray 81 is inserted into the tray storage unit 800 and stored in the tray storage unit 800.

[Paper Tray 81]
FIG. 31 is a schematic cross-sectional view of the paper feed tray 81. The paper feed tray 81 includes a rectangular box-shaped tray main body 801, a rectangular paper feed plate 802, and an elastic body (for example, a spring) 803 as an urging member. The paper feed plate 802 is disposed inside the tray main body 801 (specifically, the upper portion of the bottom surface 801a of the tray main body 801), on which printer paper is placed. The spring 803 is connected between one end of the paper feed plate 802 and one end of the bottom surface 801 a of the tray main body 801 in the insertion direction of the paper feed tray 81. Due to the restoring force of the spring 803, one end of the sheet feeding plate 802 is biased in a direction away from the bottom surface 801 a of the tray body 801.

[Wireless transmission apparatus 20]
The wireless transmission device 20 is installed at one end of the paper feed plate 802 in the insertion direction of the paper feed tray 81. The storage unit 21 of the wireless transmission device 20 stores sheet information as content information in addition to the ID information. The paper information is information relating to the printer paper such as the type and size of the printer paper. Note that the reply signal includes paper information in addition to the ID information.

[Printer body 82]
FIG. 32 is a schematic cross-sectional view of the printer main body 82. The printer main body 82 includes an external transmission / reception device 10 and a display unit 804.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the sheet feeding plate 802. Here, the transmission / reception coil L1 is installed on the upper surface portion 800a of the tray storage portion 800, which is an extension line in the moving direction of one end portion of the sheet feeding plate 802.

  The information detection unit 109 of the external transmission / reception device 10 detects paper information in addition to the ID information. The control unit 11 obtains the number of printer sheets stored in the sheet feed tray 81 based on the acquired communication distance. The control unit 11 stores in advance a number correspondence table created based on the relationship between the communication distance and the number of printer sheets. In the number correspondence table, a plurality of sheets and a plurality of communication distances are associated with each other. In the number correspondence table, the longer the communication distance, the larger the number of sheets corresponding to the communication distance. Further, the control unit 11 outputs, to the display unit 804, management information in which the ID information detected by the information detection unit 109 and the sheet information and the obtained number of sheets are written instead of the measurement result information.

  In addition, the control unit 11 outputs a remaining amount decrease signal to the display unit 401 when the obtained number of sheets is equal to or less than the specified amount.

  The display unit 804 displays management information (ID information, paper information, the number of sheets) from the external transmission / reception device 10. In addition, when the display unit 804 receives the remaining amount decrease signal from the external transmission / reception device 10, the display unit 804 displays a remaining amount decrease notification image (for example, the remaining amount “low”).

<Operation>
Next, the operation by the paper management system will be described.

  When the paper feed tray 81 is stored in the tray storage unit 800 of the printer main body 82, various signals (transmission signals and reply signals) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and the external The control unit 11 of the transmission / reception device 10 periodically acquires a communication distance. Further, the control unit 11 obtains the number of printer papers stored in the paper feed tray 81 based on the acquired communication distance. For example, the control unit 11 detects the number of sheets corresponding to the communication distance from the number correspondence table. Next, the control unit 11 writes the ID information and paper information detected by the information detection unit 109 and the obtained number of sheets in the management information, and outputs the management information to the display unit 804. As a result, the management information displayed on the display unit 804 is periodically updated.

  Here, when the number of printer papers stored in the paper feed tray 81 decreases, one end of the paper feed plate 802 moves upward of the tray body 801 (that is, the upper surface of the tray storage unit 800 by the restoring force of the spring 803). Part 800a). Accordingly, the reception state of the transmission signal in the wireless transmission device 20 is improved. Thereby, the communication distance required by the wireless transmission device 20 is shortened, and the calculated number of sheets is reduced. That is, the number of sheets displayed on the display unit 804 is reduced.

  If the control unit 11 of the external transmission / reception device 10 determines that the obtained number of sheets is equal to or less than the specified amount, the control unit 11 outputs a remaining amount reduction signal. Therefore, “remaining amount“ low ”” is displayed on the display unit 804. Thereby, it is possible to prompt the user to replenish paper. Note that the display unit 804 may emit a warning sound together with the remaining amount decrease signal.

<Effect>
As described above, the type and number of sheets stored in the sheet feed tray can be managed simultaneously. If the paper information is displayed on the display screen of the personal computer, it is possible to prevent the paper having different sizes from being specified when printing from the personal computer.

  In addition, since a wireless transmission device (for example, a wireless tag) can be manufactured with a size of about several millimeters square, it can be mounted in an arbitrary space in a paper feed tray.

  In this application example, an example using the number correspondence table is shown, but the number of sheets corresponding to the communication distance may be obtained using a calculation formula.

  In this application example, the communication distance is periodically obtained. However, if the communication distance is obtained according to the operation of the printer body, the measurement of the communication distance when the printer is not operating can be omitted. Can do.

(Application example 5)
<Configuration>
Next, an ink management system to which the transmission / reception system according to the first embodiment is applied will be described. This ink management system manages ink contained in an ink cartridge built in an ink jet printer.

  FIG. 33A is an external view of an inkjet printer. A cartridge holder portion 91 is formed in the printer main body 90. This ink management system includes an external transmission / reception device 10, a wireless transmission device 20, a cartridge holder 91, and an ink cartridge 92. FIG. 33B is an external view of the cartridge holder portion 91. The ink cartridge 92 is attached in the cartridge holder portion 91. FIG. 34 is a schematic cross-sectional view of the cartridge holder 91 and the ink cartridge 92.

[Ink cartridge 92]
The ink cartridge 92 stores ink. In addition, a floating member 302 floats on the liquid level of the ink stored in the ink cartridge 92.

[Wireless transmission apparatus 20]
The wireless transmission device 20 is installed on the surface of the floating member 302. The storage unit 21 of the wireless transmission device 20 stores ink information as content information in addition to the ID information. Ink information is information about ink, such as the color and type of ink, for example. The return signal includes ink information in addition to the ID information.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the floating member 302. Here, the transmission / reception coil L1 is disposed on the upper portion of the cartridge holder portion 91 which is on an extension line in the movement direction.

  The information detection unit 109 of the external transmission / reception device 10 detects ink information in addition to the ID information. The control unit 11 obtains the internal volume of the ink stored in the ink cartridge 92 based on the acquired communication distance. In addition, the control unit 11 outputs management information in which the ID information and ink information detected by the information detection unit 109 and the obtained ink content are written, instead of the measurement result information, to the display unit 901.

  In addition, the control unit 11 outputs a remaining amount decrease signal to the display unit 901 when the ink content is equal to or less than the specified amount.

  The display unit 901 displays management information (ID information, ink information, ink content) from the external transmission / reception device 10. In addition, when the display unit 901 receives the remaining amount decrease signal from the external transmission / reception device 10, the display unit 901 displays a remaining amount decrease notification image (for example, the remaining amount “low”). Note that the display unit 901 may emit a warning sound together with the remaining amount decrease signal.

<Operation>
Next, the operation by the ink management system will be described.

  When the ink cartridge 92 is housed in the cartridge holder 91, various signals (transmission signal, reply signal) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and the external transmission / reception device 10 The control unit 11 periodically acquires a communication distance. Further, the control unit 11 obtains the internal volume of the ink stored in the ink cartridge 92 based on the acquired communication distance. Next, the control unit 11 writes the ID information and ink information detected by the information detection unit 109 and the obtained ink content in the management information, and periodically outputs the management information to the display unit 901. Management information displayed on the display unit 901 is periodically updated.

  If the control unit 11 of the external transmission / reception device 10 determines that the obtained ink content is equal to or less than the specified amount, the control unit 11 outputs a remaining amount decrease signal. Therefore, “remaining amount“ low ”” is displayed on the display unit 901. Thereby, replacement of the ink cartridge can be urged.

<Effect>
As described above, the type and content of ink stored in the ink cartridge can be managed simultaneously.

  In addition, the floating member 302 provided with a wireless transmission device (for example, a wireless tag) can be manufactured with a size of about several millimeters square, and thus can be mounted inside a small ink cartridge.

  In each of the application examples of the present embodiment, the example in which the transmission / reception system according to the first embodiment is applied has been described. However, the first modification, the second embodiment, and the first embodiment of the first embodiment are described. Each of the three embodiments is naturally applicable.

  As described above, the present invention can detect the position of the wireless transmission device, so that the present invention can be applied to a container management system for managing the content of contents stored in a predetermined storage container, or a paper feed tray. This is useful as a paper management system for managing the stored printer paper.

The figure for demonstrating the whole structure and reply signal of the transmission / reception system by 1st Embodiment of this invention. The graph which shows the relationship between the reception level of a signal, and communication distance. (A) The graph which shows the relationship between communication S / N and communication distance. (B) A graph showing the relationship between error rate and communication S / N. (C) A graph showing the relationship between the number of error corrections and the communication distance. The block diagram which shows the internal structure of the external transmission / reception apparatus shown in FIG. The block diagram which shows the internal structure of the transmission signal supply part shown in FIG. The wave form diagram for demonstrating a transmission signal. The block diagram which shows the internal structure of the decoding part shown in FIG. The block diagram which shows the internal structure of the wireless transmission apparatus shown in FIG. The figure which shows an example of a level information corresponding | compatible table. The block diagram which shows the internal structure of the decoding part and signal state detection part which were shown in FIG. The block diagram which shows the internal structure of the reply signal supply part shown in FIG. The wave form diagram for demonstrating the reply signal transmitted according to a load modulation system. The wave form diagram for demonstrating the reply signal transmitted according to another load modulation system. Waveform diagram for explaining a transmission signal transmitted in the transmission and reception system according to the first modification of the first embodiment of the present invention (A) A figure showing an example of a time amplitude level correspondence table. FIG. 4B is a diagram illustrating an example of an amplitude level distance correspondence table. The figure for demonstrating the operation | movement in the transmission / reception system by 2nd Embodiment of this invention. The figure which shows an example of a time distance correspondence table. The figure which shows an example of a transmission frequency amplitude level corresponding table. The figure for demonstrating the operation | movement in the transmission / reception system by 3rd Embodiment of this invention. The figure which shows an example of a transmission frequency distance corresponding | compatible table. The figure which shows the structure of the container management system by the application example 1 of embodiment of this invention. The figure which shows the example of installation of the wireless type transmission apparatus in the floating member shown in FIG. The figure for demonstrating the case where the liquid in the storage container shown in FIG. 21 decreases. The figure which shows the example of installation of the wireless type transmission apparatus in the floating member shown in FIG. The figure which shows the modification 1 of the storage container shown in FIG. The figure which shows the modification 2 of the storage container shown in FIG. The figure for demonstrating the case where the liquid in the storage container shown in FIG. 26 decreases. The figure which shows the structure of the fuel cell system by the application example 2 of embodiment of this invention. The figure which shows the structure of the infusion management system by the application example 3 of embodiment of this invention. FIG. FIG. 31 is a schematic sectional view of the paper feed tray shown in FIG. 30. Sectional schematic diagram for demonstrating the structure of the paper management system by the application example 4 of embodiment of this invention. (A) External view of printer. (B) External view of cartridge holder. The figure for demonstrating the structure of the ink management system by the application example 5 of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 External transmission / reception apparatus 20 Wireless type transmission apparatus 11, 26 Control part 12 Transmission signal supply part 13, 22 Transmission / reception part 14 Level setting part 15, 24 Decoding part 21 Storage part 23 Voltage generation part 25 Signal state detection part 27 Reply signal supply Units 101, 206 encoding processing units 102, 207 error correction code adding unit 103 transmission data generating units 104, 209 modulation circuit 105 reception amplification circuit 106, 201 demodulation circuit 107, 202 error correction circuit 108, 203 decoding processing unit 109 information Detection unit 204 Reception level measurement unit 205 Error location counting circuit 208 Reply data generation unit 30, 30A, 30B Container 301, 301A Container body 302 Floating member 302A Partition member 40 Display device 50 Fuel cell unit 500 Power generation unit 501 Fuel supply pump 502 DMFC power generation cell 503 Voltage conversion circuit 0 Electronic device 601 Control microcomputer 602 Display unit 71 Infusion pack 72 Infusion stand 80, 90 Printer 81 Paper feed tray 82 Printer main body 800 Tray storage unit 801 Tray main body 802 Paper feed plate 803 Energizing members 804, 901 Display unit 91 Cartridge holder Part 92 Ink cartridge

Claims (22)

An external transmission / reception apparatus that sequentially transmits a plurality of transmission signals having different amplitude levels by transmitting a carrier wave and sequentially changing the transmission level of the carrier wave, and a wireless transmission apparatus that performs load modulation on the carrier wave from the external transmission / reception apparatus Is a system that communicates with
The wireless transmission device includes:
A first transmission / reception unit for receiving a carrier wave from the external transmission / reception device;
A signal state detection unit for detecting a reception state of a transmission signal received by the first transmission / reception unit;
When the reception state of the transmission signal detected by the signal state detection unit satisfies a predetermined condition, the communication distance between the external transmission / reception device and the wireless transmission device is determined based on the transmission level of the transmission signal. A first control unit for obtaining and outputting reply information including distance information indicating the obtained communication distance;
A return signal supply unit that generates a return signal based on return information from the first control unit and supplies the generated return signal;
The first transmission / reception unit transmits the reply signal by load-modulating a carrier wave from the external transmission / reception device based on the reply signal supplied by the reply signal supply unit,
The external transmission / reception device is:
A second controller that sequentially outputs a plurality of level information indicating different amplitude levels, and sequentially outputs a plurality of transmission information;
A transmission signal supply unit that supplies a carrier wave and supplies a transmission signal by modulating the carrier wave based on the transmission information when receiving transmission information from the second control unit;
A level setting unit that sets the transmission level of the carrier wave supplied from the transmission signal supply unit to the amplitude level indicated in the level information output from the first control unit;
A second transmission / reception unit that transmits a carrier wave whose transmission level is set by the level setting unit, and that receives a return signal transmitted by load modulation in the wireless transmission device;
A transmission / reception system comprising: an information detection unit that detects distance information from a reply signal received by the second transmission / reception unit. In claim 1,
The transmission information output from the second control unit includes level information output together with the transmission information among the plurality of level information,
The first control unit detects level information from the transmission signal received by the first transmission / reception unit, and the reception state of the transmission signal detected by the signal state detection unit satisfies a predetermined condition. And a transmission / reception system that obtains the communication distance based on the amplitude level indicated in the detected level information. In claim 1,
The second control unit measures an elapsed time from the time when the first transmission signal is transmitted by the second transmission / reception unit, and outputs level information indicating an amplitude level according to the elapsed time,
The first control unit measures an elapsed time from the time when the first transmission signal is received by the first transmission / reception unit, and the reception state of the transmission signal detected by the signal state detection unit is a predetermined condition. The transmission / reception system is characterized in that the communication distance is obtained based on an elapsed time when it is determined that the condition is satisfied. In claim 1,
The second control unit counts the number of transmissions of the transmission signal by the second transmission / reception unit, and outputs level information indicating an amplitude level according to the number of transmissions;
The first control unit counts the number of times the transmission signal is received by the first transmission / reception unit, and determines that the reception state of the transmission signal detected by the signal state detection unit satisfies a predetermined condition. A transmission / reception system characterized in that the communication distance is obtained based on the number of receptions. In any one of Claims 1-4,
The signal state detection unit measures an amplitude level of a transmission signal received by the first transmission / reception unit,
The first control unit determines that the transmission state of the transmission signal satisfies a predetermined condition when the amplitude level of the transmission signal measured by the signal state detection unit is a predetermined level. Transmission / reception system. In any one of Claims 1-4,
The signal state detection unit counts the number of error locations occurring in the transmission signal received by the first transmission / reception unit,
The first control unit determines that the reception state of the transmission signal satisfies a predetermined condition when the number of error points counted by the signal state detection unit is a predetermined number. . In claim 5 or claim 6,
When the transmission signal supply unit receives the transmission information from the second control unit, the transmission signal supply unit generates a transmission signal provided with a section corresponding to the transmission information and in which the fluctuation of the amplitude level continues, and the generated transmission A transmission / reception system characterized by supplying a signal. In claim 1,
A storage container in which the wireless transmission device is provided so as to store the predetermined content and change the communication distance according to an increase or decrease in the content of the content;
The transmission / reception system, wherein the second control unit further obtains an internal volume of the predetermined content based on a communication distance indicated in the distance information detected by the information detection unit. In claim 1,
A storage container for storing a predetermined content that is liquid; and
A floating member that floats on the liquid level of the predetermined content stored in the storage container,
The wireless transmission device is provided on the surface of the floating member,
The second control unit further determines an internal volume of a predetermined content stored in the storage container based on a communication distance indicated in the distance information detected by the information detection unit. Transmission / reception system. In claim 1,
A storage container for storing predetermined contents;
A partition member disposed inside the storage container and moving in accordance with an increase or decrease in the content of the predetermined content stored in the storage container;
The wireless transmission device is provided on the partition member,
The second control unit further determines an internal volume of a predetermined content stored in the storage container based on a communication distance indicated in the distance information detected by the information detection unit. Transmission / reception system. In claim 1,
A storage container in which the predetermined contents are stored and the outer shape expands and contracts in accordance with the increase or decrease in the internal volume of the contents;
The wireless transmission device is provided on the surface of the container,
The second control unit further determines an internal volume of a predetermined content stored in the storage container based on a communication distance indicated in the distance information detected by the information detection unit. Transmission / reception system. In any one of claims 8 to 11,
A fuel cell unit including a power generation unit that generates power using liquid fuel;
The storage container stores liquid fuel used by the power generation unit,
The second control unit further obtains an internal volume of the liquid fuel stored in the storage container based on a communication distance indicated by the distance information detected by the information detection unit. system. In claim 1,
An infusion container for containing a predetermined infusion; and
A floating member floating on the liquid surface of the predetermined infusion contained in the infusion container;
A container mounting portion for mounting the infusion container, and
The wireless transmission device is provided on the surface of the floating member,
The second control unit further obtains an internal volume of a predetermined infusion stored in the infusion container based on a communication distance indicated by the distance information detected by the information detection unit. Transmission / reception system. In claim 1,
A printer including a paper feed tray for storing printer paper; and a printer main body having a tray storage portion in which the paper feed tray is inserted to store the paper feed tray;
The paper feed tray includes a paper feed tray main body, a paper feed plate disposed inside the paper feed tray main body and on which the printer paper is placed, and a bottom surface of the paper feed tray main body in the insertion direction of the paper feed tray. An urging member that connects one end of the sheet feeding plate and one end of the sheet feeding plate and urges the sheet feeding plate in a direction away from the bottom surface of the tray body,
The wireless transmission device is provided at one end of the sheet feeding plate,
The second control unit further obtains the number of sheets of printer paper stored in the paper feed tray based on the communication distance indicated by the distance information detected by the information detection unit. system. In claim 1,
The printer further includes an ink cartridge that stores predetermined ink, a floating member that floats on a liquid surface of the ink stored in the ink cartridge, and a printer main body having a cartridge holder portion that stores the ink cartridge therein. ,
The wireless transmission device is provided on the surface of the floating member,
The second control unit further obtains an internal volume of ink stored in the ink cartridge based on a communication distance indicated by the distance information detected by the information detection unit. . In any one of claims 8 to 11,
The wireless transmission device includes:
A storage unit that stores content information that is information about the content;
The first control unit outputs reply information including distance information indicating the obtained communication distance and content information stored in the storage unit,
The information detection unit detects the distance information and the content information from a reply signal received by the second transmission / reception unit,
The external transmission / reception device is:
The transmission / reception system further comprising a display unit that displays at least one of the content volume obtained by the second control unit and the content information detected by the information detection unit. A transmission / reception method by an external transmission / reception device in which a transmission level of a carrier wave can be changed, and a wireless transmission device that performs load modulation on a carrier wave from the external transmission / reception device,
The external transmission / reception apparatus transmits a carrier wave and sequentially transmits a plurality of transmission signals having different amplitude levels by sequentially changing the transmission level of the carrier wave; and
A carrier wave receiving step in which the wireless transmission device receives the carrier wave transmitted in the sending step;
A state detection step in which the wireless transmission device detects a reception state of the transmission signal received in the carrier wave reception step;
When the reception state of the transmission signal detected in the state detection step satisfies a predetermined condition in the wireless transmission device, the external transmission / reception device and the wireless transmission device based on the transmission level of the transmission signal Calculating a communication distance between
The wireless transmission device generates a return signal including distance information indicating the communication distance obtained in the calculation step;
A reply step of transmitting the reply signal by load-modulating a carrier wave from the external transmission / reception apparatus based on the reply signal generated in the generating step;
A reply signal receiving step in which the external transmission / reception device receives the reply signal transmitted in the reply step;
And a detecting step of detecting distance information from the reply signals received in the reply signal receiving step. In claim 17,
In the transmission step, the transmission signal is transmitted by changing the transmission level of the carrier wave and modulating the carrier wave based on transmission information including level information indicating the transmission level,
In the calculation step, the wireless transmission device detects level information from the transmission signals received in the carrier wave reception step, and the reception state of the transmission signals detected in the state detection step satisfies a predetermined condition. The communication distance is obtained based on the transmission level indicated in the detected level information. In claim 17,
The external transmission / reception device, a transmission elapsed time counting step for measuring an elapsed time from the time when the first transmission signal is transmitted among the plurality of transmission signals in the transmission step;
The wireless transmission device further comprises a reception elapsed time counting step for measuring an elapsed time from the time when the first transmission signal is received in the carrier wave reception step,
In the transmission step, when the external transmission / reception device transmits the transmission signal, the transmission level of the transmission signal is set to an amplitude level corresponding to the elapsed time measured in the transmission elapsed time counting step,
In the calculating step, an elapsed time measured in the reception elapsed time counting step when the wireless transmission device determines that the reception state of the transmission signal detected in the state detection step satisfies a predetermined condition. The communication distance is obtained based on the transmission / reception method. In claim 17,
The external transmission / reception apparatus counts the number of transmissions of the transmission signal in the transmission step,
The wireless transmission device further includes a reception number counting step of counting the number of receptions of the transmission signal in the carrier wave reception step,
In the transmission step, when the external transmission / reception device transmits the transmission signal, the transmission level of the transmission signal is set to an amplitude level corresponding to the number of transmissions counted in the transmission number counting step,
In the calculating step, based on the number of receptions counted in the reception number counting step when the wireless transmission device determines that the reception state of the transmission signal detected in the state detection step satisfies a predetermined condition. And determining the communication distance. In any one of claims 17 to 20,
In the state detection step, the amplitude level of the transmission signal received in the carrier wave reception step is measured,
In the calculation step, when the amplitude level of the transmission signal measured in the state detection step is a predetermined level, it is determined that the reception state of the transmission signal satisfies a predetermined condition. In any one of claims 17 to 20,
In the state detection step, the number of error locations occurring in the transmission signal received in the carrier wave reception step is counted,
The transmission / reception method characterized in that the calculation step determines that the reception state of the transmission signal satisfies a predetermined condition when the number of error locations of the transmission signal counted in the state detection step is a predetermined number.

Images