KR-20260067348-A - COMMUNICATION APPARATUS AND CONTROL METHOD OF COMMUNICATION APPARATUS

KR20260067348AKR 20260067348 AKR20260067348 AKR 20260067348AKR-20260067348-A

Abstract

The present invention provides a communication device capable of preventing misreading of a wireless tag different from the communication target without installing a read proposal antenna, etc. The communication device comprises a wireless device that performs communication with a wireless tag, a loop antenna that outputs a magnetic field corresponding to a transmission signal regarding communication with the wireless tag and performs communication with the wireless tag, a plurality of loop antennas each that independently performs communication with the wireless tag, a communication control means that outputs a transmission signal to a communication target loop antenna among the plurality of loop antennas, and a control means that controls the generation of a magnetic field to eliminate the leakage magnetic field at the communication target loop antenna to a loop antenna that is different from the communication target loop antenna and is not the communication target loop antenna.

Inventors

시게루 아리사와

Assignees

요시카와코교 알에프 세미콘 가부시키가이샤

Dates

Publication Date: 20260512
Application Date: 20251104
Priority Date: 20241105

Claims (10)

It is a communication device that communicates with a wireless tag, and A loop antenna that outputs a magnetic field in response to a transmission signal regarding communication with the wireless tag and performs communication with the wireless tag, and a plurality of loop antennas each independently perform communication with the wireless tag, and A communication control means for outputting a transmission signal to a loop antenna of a communication target among the plurality of loop antennas above, A communication device characterized by having a control means for controlling the generation of a magnetic field that eliminates a leakage magnetic field from the loop antenna of the communication target, in a loop antenna that is different from the loop antenna of the communication target and is not a communication target.
A communication device according to claim 1, wherein the control means controls the generation of a magnetic field opposite to the outer magnetic field of the communication target loop antenna at a loop antenna that is not a communication target.
A communication device according to claim 1 or 2, wherein the control means, when not the loop antenna of the communication target, has a capacitance connected to the loop antenna, and controls the resonance frequency of the connected loop antenna and the circuit having the capacitance to be tuned to a frequency different from the frequency of the carrier wave of the transmission signal.
A communication device according to paragraph 3, wherein the control means controls the resonance frequency of a circuit including a connected loop antenna and the capacitance to be tuned to a frequency lower than the frequency of the carrier wave of a transmission signal.
A communication device according to paragraph 3, wherein the control means is provided with a switch to connect the communication control means to the loop antenna when it is a communication target loop antenna, and to connect the capacity to the loop antenna when it is not a communication target loop antenna.
A communication device according to claim 1 or 2, wherein the control means outputs a signal having the same phase as a transmission signal output to a loop antenna of a communication target to a loop antenna that is not a communication target.
A communication device according to claim 6, wherein the control means outputs a transmission signal, whose level is adjusted in response to the magnetic field strength at the loop antenna of the communication target, to a loop antenna that is not the communication target.
A communication device according to claim 6, wherein the control means outputs a transmission signal with a current level attenuated in response to the magnetic field strength of a communication target loop antenna to a loop antenna that is not a communication target.
A communication device according to claim 6, wherein the control means outputs a carrier wave of a transmission signal, whose level is adjusted in response to the strength of the magnetic field at a communication target loop antenna, to a loop antenna that is not a communication target.
A control method for a communication device having a plurality of loop antennas, each of which independently communicates with a wireless tag, wherein the loop antenna outputs a magnetic field in response to a transmission signal regarding communication with a wireless tag and performs communication with the wireless tag. A communication control process that outputs a transmission signal to a loop antenna of a communication target among multiple loop antennas, and A control method for a communication device characterized by having a control process that controls a loop antenna other than the loop antenna of the communication target to generate a magnetic field that eliminates the leakage magnetic field from the loop antenna of the communication target.

Description

Communication apparatus and control method of communication apparatus The present invention relates to a communication device that communicates with a wireless tag and a control method thereof. A reader and reader-writer (hereinafter referred to as reader-writer, including reader, without distinction) using a frequency band such as the HF (High Frequency) band in accordance with ISO 15693 standards combine a loop antenna installed on the reader-writer side with a loop antenna mounted on the wireless tag side, such as an RFID (Radio Frequency Identification) tag or an RFID card, through electromagnetic induction to perform non-contact reading and writing of data for the wireless tag. For example, the reader-writer uses a specific modulation method on a high-frequency carrier signal to embed information, such as read commands from a wireless tag, and outputs it in the form of a magnetic field from a loop antenna. The wireless tag obtains operating power by treating the magnetic field generated by the reader-writer as an electrical signal through the electromagnetic induction of the loop antenna. Furthermore, the wireless tag decodes the read commands contained in the received electrical signal, stores the decoded content in its internal memory, and transmits the data back to the reader-writer via a load switch or the like. The reader-writer then performs data reading by receiving the transmitted signal from the wireless tag via the loop antenna and decoding it. In addition, as illustrated in FIG. 11(A), a reader-writer is proposed that installs a plurality of loop antennas and performs data reading and writing for wireless tags with each loop antenna. The reader-writer equipped with a plurality of loop antennas designs a switch circuit between a communication control unit (1110) that performs control of communication, etc., and an antenna unit (1120) that includes a loop antenna (1121) and a matching circuit (1122), and performs data reading and writing for wireless tags (1123) placed on the loop antenna (1121) of the communication target by selecting the loop antenna (1121) that performs communication. In a reader-writer equipped with multiple loop antennas as described above, it is required to reduce the overall occupied area of the loop antennas by narrowing the spacing between the antennas. However, if the spacing between the loop antennas is narrowed, data writing or reading may be performed incorrectly on the wireless tag placed on the loop antenna that contacts the loop antenna of the communication target, and there may be cases where the wireless tags placed on each loop antenna cannot be read or written independently of each other. This is because, as shown in FIG. 11(B), the magnetic field (1142) generated by the loop antenna (1141) of the communication target leaks out to the outside of the loop antenna (1141), and the magnetic field (1142) is supplied to the wireless tag placed on the connected loop antenna (1143), thereby enabling data reading and writing. As an example of a countermeasure for this, Patent Document 1 proposes a technology to prevent misreading of an RF tag placed in close proximity to an RF tag of a sample container adjacent to a target for reading. Additionally, Patent Document 2 proposes a technology to prevent misreading of an RFID tag placed on an adjacent antenna by installing a reading antenna that reads an RFID tag and a reading limiting antenna that limits reading by another adjacent reading antenna, and controlling them appropriately. [Patent Document 1] Japanese Patent Publication No. 2011-75360 [Patent Document 2] Japanese Patent Publication No. 2021-49331 FIG. 1 is a drawing illustrating the prevention of misreading of a wireless tag, etc., in an embodiment of the present invention. FIG. 2 is a drawing showing an example of the configuration of a communication device according to a first embodiment. FIG. 3 is a diagram showing an example of the configuration of a level adjustment circuit. FIG. 4 is a drawing illustrating the prevention of misreading of a wireless tag, etc. in a communication device according to a first embodiment. FIG. 5 is a drawing showing another configuration example of a communication device in the first embodiment. FIG. 6 is a drawing showing another configuration example of a communication device in the second embodiment. FIG. 7 is a diagram showing an example of the configuration of a horizontal reading prevention circuit. FIG. 8 is a drawing illustrating the prevention of misreading of a wireless tag, etc. in a communication device in a second embodiment. FIG. 9 is a diagram illustrating the generation of a signal at an adjacent loop antenna. FIG. 10 is a diagram showing an example of the relationship between the resonant frequency at adjacent loop antennas and the operating voltage obtained by the wireless tag. FIG. 11 is a drawing illustrating a reader writer having multiple loop antennas. Next, embodiments of the present invention will be