JP5527848B2 - Proximity feeding / communication equipment - Google Patents

Description

  The present invention relates to a proximity power supply / communication device, and in particular, even when proximity power supply is performed from the base station side to the portable device side or when proximity power supply is not performed, the user uses the device without switching a switch or the like. The present invention relates to a proximity power feeding / communication device.

  A device that uses electromagnetic induction energy based on a radiated magnetic field of an electromagnetic wave transmitted from a base station as operating energy of a portable device, that is, a device that obtains operating energy of a portable device from the base station side by proximity power feeding is known.

  Conventionally, keyless entry devices for automobiles, RFID tag devices, IC card devices, and the like have been put to practical use as such devices. These devices generally use the same frequency for proximity power feeding and communication, and the base station and the mobile device communicate with each other using the same frequency as the electromagnetic wave used for proximity power feeding (hereinafter referred to as this). Called single frequency communication method).

  FIG. 12 is a time chart showing operations of a base station and a portable device in a conventional single frequency communication method using an LF (Low Frequency) signal.

  As shown in FIG. 12, the base station repeats the LF transmission period, the LF response reception period, and the pause, and the portable device repeats the LF reception period, the LF response transmission period, and the pause. This is because transmission and reception cannot be performed simultaneously at the same frequency. For this purpose, each base station and portable device has an LF transmission / reception antenna and an LF transmission / reception circuit. The LF reception period of the portable device corresponds to the LF transmission period of the base station, and the LF response reception period of the base station corresponds to the LF response transmission period of the portable device.

  The base station switches the LF transmission / reception circuit to the LF transmission circuit during the LF transmission period, and transmits the LF signal. This LF signal generally includes a proximity power feeding LF signal and a communication LF signal. The LF transmission period is a period in which the radiated magnetic field due to the electromagnetic wave of the LF signal is turned on, and the portable device is proximity-fed during this period. Communication can also be performed by including a communication LF signal in the LF signal.

  In the LF response reception period, the LF transmission / reception circuit is switched to the LF reception circuit, and transmission of the LF signal is stopped. The LF response reception period is a period in which the radiated magnetic field is turned off, and during this period, an LF response signal is waited from the portable device that is supplied with power in the LF transmission period. The pause is provided so as not to continuously occupy one frequency (according to the Radio Law).

  The portable device switches the LF transmission / reception circuit to the LF reception circuit during the LF reception period, receives the LF signal from the base station, and generates power by proximity power feeding. If the communication LF signal is included in the LF signal, response processing is performed. In the LF response transmission period, the LF transmission / reception circuit is switched to the LF transmission circuit and an LF response signal is transmitted. The pause is provided so as not to continuously occupy one frequency (according to the Radio Law).

  As described above, in the single frequency communication method using the LF signal, first, the LF signal is transmitted from the base station. The portable device receives the LF signal transmitted from the base station, generates electric power based on the radiated magnetic field of the electromagnetic wave, operates the circuit including the LF transmission / reception circuit with the electric power, and transmits the LF response signal. After completing the transmission of the LF signal, the base station receives the LF response signal transmitted from the portable device with the LF receiver.

  For example, in the case of an automobile keyless entry device, each of the automobile base station and the key portable device includes an LF transmission / reception antenna and an LF transmission / reception circuit, and communicates with proximity power feeding using an LF signal. In this case, a period during which proximity power supply (generally including transmission of a communication LF signal) from the base station to the portable device is different from a period during which a response signal is transmitted from the portable device to the base station.

  In the case of an RFID tag device, the base station on the IC tag reader side and the portable device on the IC tag side are the same except that the signal to be transmitted and received is an RF (Radio Frequency) signal. It communicates with proximity power feeding using RF signals. Even in this case, proximity power feeding from the base station to the portable device and communication between the base station and the portable device are single frequency communication methods, and transmission and reception cannot be performed simultaneously at the same frequency.

  In the single frequency communication method using an RF signal, first, an RF signal is transmitted from a base station. This RF signal generally includes a proximity feeding RF signal and a communication RF signal. The portable device receives the RF signal transmitted from the base station, generates electric power based on the radiated magnetic field of the electromagnetic wave, operates the circuit including the RF transmission / reception circuit with the electric power, and transmits the RF response signal. After completing the transmission of the RF signal, the base station receives the RF response signal transmitted from the portable device with the RF receiver. Such a transmission / reception period is also realized in an IC card device of a single frequency communication system using an RF signal.

  Also known is a method (hereinafter referred to as a bidirectional communication method) in which uplink and downlink proximity power feeding and communication are simultaneously performed between a base station and a portable device using different frequencies in the same frequency band.

  FIG. 13 is a time chart showing operations of the base station and the portable device in the conventional bidirectional communication method using the LF signal. This method is characterized in that the base station can always receive a response signal from the portable device.

  As shown in FIG. 13, the base station repeats the LF transmission period for transmitting the LF signal of the frequency F1 and the pause, and at the same time repeats the LF response reception period and the pause for receiving the LF response signal of the frequency F2 different from F1. . The portable device repeats the LF reception period for receiving the LF signal at the frequency F1 and the pause, and simultaneously repeats the LF response transmission period for sending the LF response signal at the frequency F2 and the pause.

  Therefore, the base station has LF transmission means for transmitting the LF signal of frequency F1 and LF reception means for receiving the LF signal of frequency F2, and the portable device has LF reception means and frequency for receiving the LF signal of frequency F1. Has LF transmission means to transmit F2 LF signal. The pause is provided so as not to continuously occupy one frequency (according to the Radio Law).

  The base station sets the LF transmission period long enough to generate the power required to start up the mobile device, and continues to transmit the LF signal of frequency F1 during this LF transmission period. In the LF reception response period, an LF response signal of frequency F2 is waited for from a portable device that has been supplied with proximity by the LF signal. In the LF transmission period, the radiated magnetic field due to the electromagnetic wave of the LF signal is turned on, and in the idle period, the radiated magnetic field is turned off.

  The base station performs proximity power feeding using the radiated magnetic field to the portable device while the radiated magnetic field is on during the LF transmission period. The LF signal generally includes a proximity power feeding LF signal and a communication LF signal. On the other hand, the portable device that is fed during the period in which the radiation magnetic field is on (LF transmission period) transmits the LF response signal in the LF response period that is the same as the LF transmission period.

  For example, the ISO 11785 technical guideline for animal identification using RFID tags defines the following power feeding method as an example of using LF (134.2 kHz ± 1.8 kHz).

  The radiated magnetic field from the LF transmitter on the base station side is set to 50 msec on and 3 msec off, and this operation is repeated to supply power to the portable device side by the radiated magnetic field from the base station. The portable device is supplied with proximity power during the on-period (50 msec) of the radiation magnetic field. During this period, the LF receiver on the base station side always waits for a response signal from the portable device. The proximity power feeding and communication transmission / reception period from the base station to the portable device presented in the technical guideline of ISO11785 is also realized in a bidirectional communication type IC card using an RF signal.

  Non-Patent Document 1 describes an entrance / exit management system that activates a portable device using an LF signal and transmits a response signal from the portable device to a base station using a UHF signal. This entrance / exit management system includes a tag reader, an external antenna, and an active tag. Here, the tag reader includes an LF transmission / reception antenna, an LF transmission / reception circuit, a UHF antenna, a UHF reception circuit, a control circuit (CPU), an external antenna includes an LF antenna and an LF transmission circuit, an active tag includes an LF transmission / reception antenna, LF transceiver circuit, UHF antenna, UHF transmitter circuit, control circuit (CPU) and battery.

  If the battery is not depleted, the active tag is activated by the beating pattern of the LF signal from the tag reader, and transmits a UHF response signal including the ID number to the tag reader through the UHF transmission circuit. However, when the battery is depleted, the active tag operates with the electric power induced by the LF signal from the tag reader, and sends the binary FSK (Frequency Shift Keying) modulated LF signal to the tag reader. The tag reader receives this LF signal by the LF receiving circuit.

Naoshima Hideo et al., "Hands-free entry / exit management system using active tags" Panasonic Electric Works Technical Report (Vol.57 No.2), pp. 52-57

  However, the conventional single frequency communication method using the LF signal has the following problems.

  If sufficient power is available to activate the internal circuit of the portable device from the power supply of the portable device, the portable device is activated immediately upon reception of the LF signal (including the communication LF signal) from the base station. It is possible to transmit an LF response signal for the received LF signal without receiving proximity power feeding. However, if the power of the portable device is exhausted and sufficient power is not available to activate the circuit inside the portable device, the base station continuously transmits LF signals to supply the proximity power to the portable device. The portable device cannot transmit the LF response signal until the portable device has obtained the power necessary for starting up.

  In the conventional single frequency communication method, assuming that the power of the portable device is exhausted and sufficient power cannot be obtained to activate the circuit inside the portable device, the portable device can be immediately activated. Regardless of whether or not there is, the base station continuously transmits the LF signal for proximity power supply for a certain period of time, so that the power required for the portable device to activate its internal circuit can be obtained, or Depending on whether the power supply of the machine is exhausted and proximity power feeding is required, whether or not the user operates the switch etc. provided in the base station to transmit the LF signal continuously for a certain period of time It was necessary to be made to choose.

  However, the time required for communication between the base station and the portable device is assumed when the LF signal is continuously transmitted from the base station for a certain period of time regardless of whether the portable device is ready to be activated immediately. There was a problem of always becoming longer.

  In addition, when it is assumed that the LF signal is transmitted continuously for a certain period of time by operating a switch etc. provided in the base station, the user can start up the mobile device with its internal power supply in advance. It is necessary to confirm whether it is in a state of being in a portable state, etc. In addition, the switch used for starting proximity power feeding provided in the base station is actually used by being tampered with or destroyed from the outside. There was a problem that there were cases where it was not possible to use it when desired. In addition, even if the user is in a panic situation, check whether the portable device is in a state where it can be activated by its internal power supply, etc., by checking the display of the portable device every time. Since it is necessary to switch the mode of the transmission circuit with the proximity power supply activation switch provided in the base station so that the LF signal for power supply can be transmitted, it causes a trouble in actual use and is also a user for the equipment installer. It was also a problem for me.

  In addition, in the single frequency communication system, the base station becomes the LF response reception period immediately after the on-period of the radiating magnetic field elapses, and the portable device becomes the LF response transmission period immediately after the LF reception period ends, In base stations and mobile devices, stable communication over a wide area under the influence of power supply noise caused by the LF signal wrapping around to the receiving circuit and noise caused by the radiated magnetic field of the LF signal spatially wrapping around the receiving antenna There was a problem that it would be difficult to ensure the above.

  Both the single frequency communication method using RF signals and the entrance / exit management system described in Non-Patent Document 1 have the same problems as the single frequency communication method using LF signals, and the proximity provided on the base station side. There was also a problem of using a switch for starting power feeding.

  Even in a bidirectional communication system that uses LF signals of different frequencies in the same frequency band, there are problems similar to those of a single frequency communication system that uses conventional LF signals. In particular, in the two-way communication system, transmission and reception are performed at exactly the same time, so that in the base station or portable device, mutual induction induced on the conductor pattern between the antenna loop of the LF transmission antenna and the antenna loop of the LF reception antenna is performed. The noise component (antenna effect) due to the electromagnetic field cannot be excluded. As a result, the reception by the LF reception antenna is disturbed by the transmission by the LF transmission antenna, the fading effect is generated, the communication becomes unstable, and the communication distance cannot be secured.

  For example, in the base station, as shown in FIG. 14, the power noise that circulates from the transmitting circuit side to the receiving circuit side, and the electromagnetic waves of the LF signal (frequency F1) transmitted from the LF transmitting antenna circulate to the LF receiving antenna. A sneak noise is generated. Such noise becomes an obstacle when securing stable communication in a wide area.

The electromagnetic wave is a plane wave in which the electric field E and the magnetic field H are orthogonal to each other, and the power density S per unit area perpendicular to the propagation direction is given by S = E × H. The amplitude ratio E / H between the electric field E and the magnetic field H in free space is treated as a spatial impedance, and E / H = 377Ω. Using this space impedance, power density S is given by S = 377H ^2. In particular, within a quarter wavelength (λ / 4) where trigger activation or proximity power feeding is performed by electromagnetic waves, the magnetic field of the electromagnetic field is dominant, and the amplitude of the magnetic field is the spatial impedance relative to the amplitude of the electric field. The reciprocal H / E is small enough to correspond to 1/377. Therefore, if sufficient magnetic field energy is supplied from the base station to the portable device, a large electric field energy flows to the receiving circuit side, and as a result, electric noise is generated.

  Although it is not as prominent as the base station, in the portable device as well, power noise that circulates from the transmission circuit side to the reception circuit side, and electromagnetic waves of the LF signal (frequency F2) transmitted from the LF transmission antenna circulate to the LF reception antenna. Spatial wraparound noise is generated.

  As described above, whether it is a single frequency communication method or a two-way communication method, the time required for communication between the base station and the portable device is always long, the communication becomes unstable, and the communication distance is secured. There were issues such as being unable to do so.

  The present invention provides a proximity power feeding / communication device that can be used as it is without a user switching a switch or the like, whether or not proximity power feeding is performed from the base station side to the portable device side. It is intended to provide. It is another object of the present invention to provide a proximity power feeding / communication device capable of ensuring stable communication in a wide area.

In order to solve the above problems, the present invention provides:
Proximity power supply from the base station side to the portable device side, and in the proximity power supply / communication device that performs communication between the base station and the portable device, the base station has a normal communication mode and a proximity power supply mode, When communicating, first, an operation in a normal communication mode is performed in which a communication LF signal including a portable device activation signal is transmitted and a UHF response signal transmitted from the portable device is received in response to the communication LF signal . Next , following the operation in the normal communication mode, a proximity power feeding LF signal including a portable device activation signal in the terminal portion is transmitted, and the proximity power feeding is performed from the portable power device that is proximity powered by the proximity power feeding LF signal . The basic feature is that the operation in the proximity power supply mode for receiving the UHF response signal transmitted in response to the LF signal is executed .

Here, the base station, only when it does not receive a UHF response signal from the portable unit in normal communication mode, or to execute the operation in a close-feed mode, the UHF response signal from the portable unit in the normal communication mode Regardless of the presence or absence of reception, the operation in the proximity power supply mode can be executed following the normal communication mode.

  In addition, between the transmission period of the communication LF signal and the reception period of the UHF response signal in the base station, between the transmission period of the proximity power supply LF signal and the reception period of the UHF response signal, the reception of the communication LF signal in the portable device It is preferable to set a predetermined time interval between the period and the transmission period of the UHF response signal, and between the reception period of the proximity power feeding LF signal and the transmission period of the UHF response signal.

  In the present invention, based on the presence or absence of a UHF response signal from the portable device for the transmission of the LF signal from the base station, the transmission of the LF signal at the base station is switched from the normal communication mode to the proximity power supply mode, and unnecessary proximity power supply is used. Since the LF signal is not transmitted, the user can perform communication between the base station and the portable device without changing the operation of a switch or the like, and the time required for communication is always increased. The problem with the conventional apparatus can be solved.

In addition, if the base station executes the operation in the proximity power supply mode following the normal communication mode regardless of whether or not the UHF response signal is received from the portable device in the normal communication mode, one or more mobile phones Communication between the base station and each portable device is possible even when there is a device.
In the present invention, the LF band signal is used for communication from the base station to the portable device and proximity power feeding, and the frequency of the response signal communication from the portable device to the base station is greatly different from that of the LF band and the RF band. Since the UHF band signal with good radio wave propagation characteristics is used, it is possible to expand the arrangement area of the receiving antenna of the base station used to receive the response signal from the portable device. The degree of freedom of the device configuration and arrangement can be increased. In addition, efficient proximity power feeding becomes possible.
In addition, since the response signal is transmitted from the portable device in the UHF band of specific low power, the communication speed can be increased, and as a result, the time required for communication can be shortened and the application of encryption can be facilitated. It is possible to increase the confidentiality of communication and the response speed of the portable device.

Also, in the present invention, both communication from the base station to the portable device and proximity power feeding are performed in the LF band. Therefore, the base station communicates with the portable device in the configuration using one set of LF transmission antenna and LF transmission circuit. Power supply is possible, and the portable device can perform communication from the base station and proximity power supply with a configuration using one set of LF reception antenna and LF reception circuit. In this configuration, it is not necessary to switch the antenna, the transmission circuit, and the reception circuit between the base station and the portable device, so that the circuit configuration and its control can be simplified.
In addition, communication and proximity power supply are performed by setting the transmission / reception period of each signal so that communication between the base station and the portable device is not affected by wraparound noise of the LF signal or UHF response signal. This eliminates the influence of noise caused by, maximizes the effective communication distance between the base station and the portable device, and ensures stable communication.

It is a block diagram which shows embodiment of the base station which comprises the proximity electric power feeding and communication apparatus which concerns on this invention. It is a block diagram which shows embodiment of the portable device which comprises the proximity electric power feeding and communication apparatus which concerns on this invention. It is a block diagram which shows other embodiment of the base station which comprises the proximity electric power feeding and communication apparatus which concerns on this invention. It is a block diagram which shows other embodiment of the portable device which comprises the proximity electric power feeding and communication apparatus which concerns on this invention. It is a flowchart which shows the example of operation | movement in the base station of the proximity | contact electric power feeding and communication apparatus of this invention. It is a time chart which shows an example of operation | movement in the base station of the proximity | contact electric power feeding and communication apparatus of this invention. 6 is a time chart showing an example of operation when the base station receives a UHF response signal from a portable device during operation in the normal communication mode in the proximity power supply / communication device of the present invention. 6 is a time chart illustrating an example of operation when the base station does not receive a UHF response signal from a portable device during operation in the normal communication mode in the proximity power supply / communication device of the present invention. It is a flowchart which shows the other example of operation | movement in the base station of the proximity | contact electric power feeding and communication apparatus of this invention. It is a time chart which shows an example of operation | movement in normal communication mode in embodiment which integrated the mechanism of the said delay in the combination of the base station and the some portable apparatus. It is a conceptual diagram which shows the communication by the proximity electric power supply / communication device of this invention, and a proximity electric power feeding area. It is a time chart which shows the transmission and reception period of the LF signal between the base station and the portable device in the conventional single frequency communication method using the LF signal. It is a time chart which shows the period of transmission and reception of the LF signal between the base station and the portable device in the conventional bidirectional communication method using the LF signal. It is a conceptual diagram which shows the mode of the noise generation in a base station.

  The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a base station constituting a proximity power feeding / communication device according to the present invention.

  The base station shown in FIG. 1 includes an LF transmission antenna 1, an LF transmission circuit 2, a UHF reception antenna 3, a UHF reception circuit 4, and a base station side control circuit 5.

  The LF transmission antenna 1 and the LF transmission circuit 2 function as communication LF transmission means for transmitting a communication LF signal to the portable device (hereinafter, transmission / reception with this function is referred to as a normal communication mode). It functions as a proximity power feeding LF transmission means that transmits a proximity power feeding LF signal and performs proximity power feeding with a radiation magnetic field of the electromagnetic wave (hereinafter, transmission / reception with this function is referred to as a proximity power feeding mode). Proximity power is also supplied for the communication LF signal, but its transmission period is extremely short, and will be ignored below. The communication LF signal includes a portable device activation signal. The proximity power supply LF signal is continuously transmitted for a time sufficient to generate power for the portable device to be powered by proximity power supply.

  The UHF receiving antenna 3 and the UHF receiving circuit 4 function as UHF receiving means for receiving a UHF response signal transmitted from the portable device. The UHF receiver circuit 4 also has a function of decrypting the UHF response signal if the UHF response signal transmitted from the portable device is encrypted. The UHF response signal received by the UHF receiving antenna 3 and the UHF receiving circuit 4 is sent to the control circuit 5.

  The base station side control circuit 5 controls necessary control according to the UHF response signal received by the UHF receiving antenna 3 and the UHF receiving circuit 4, for example, in the case of an entrance / exit management system, controls the lock on and off of the room entrance door. For this purpose, the base station side control circuit 5 includes an interface for exchanging data with an external device.

  Further, the base station side control circuit 5 controls the operations of the LF transmission circuit 2 and the UHF reception circuit 4. Although this control will be described in detail later, when the UHF response signal is not received from the portable device in the normal communication mode, the normal communication mode is switched to the proximity power supply mode. Further, the base station side control circuit 5 performs timing control so that the LF transmission period and the UHF response reception period in the base station do not overlap. In this timing control, it is preferable to consider the spatial propagation delay of the LF signal.

  FIG. 2 is a block diagram showing an embodiment of a portable device constituting the proximity power feeding / communication device according to the present invention.

  2 includes a LF receiving antenna 6 for proximity feeding, a LF receiving antenna 7 for communication, an LF receiving circuit 8 for communication, an LF proximity receiving circuit 9, a UHF transmitting antenna 10, a UHF transmitting circuit 11, and a portable device side. A control circuit 12 is provided.

  In general, it is known that a low impedance antenna has good power efficiency for electromagnetic induction by a radiated magnetic field, and a high impedance antenna has good reception efficiency for receiving data signals. In view of this, the portable device of this embodiment includes a low-impedance proximity feeding LF reception antenna 6 and a high-impedance communication LF reception antenna 7 separately. In order to improve the directivity, the communication LF receiving antenna 7 is a two-dimensional antenna having a two-axis configuration of X-axis and Y-axis or a three-dimensional antenna having a three-axis configuration of X-axis, Y-axis, and Z-axis. Is preferred.

  In the following, the operation when the base station of FIG. 1 and the portable device of FIG. 2 are combined will be described. However, in other embodiments, a base station and a portable device, which will be described later, can be appropriately combined.

  In a portable device, the LF receiving antenna 6 for proximity feeding receives the radiated magnetic field of the electromagnetic wave of the LF signal transmitted from the LF transmitting antenna 1 of the base station, and the LF proximity receiving circuit 9 is an LF receiving antenna for proximity feeding. Electric power is generated by electromagnetic induction by the radiated magnetic field received in step 6. The LF proximity power receiving circuit 9 includes a rectifier circuit that rectifies the power from the proximity feeding LF antenna 6 and a capacitor that stores the power. The rectifier circuit and the capacitor function as a power source for the portable device. The electric power generated by the LF proximity power receiving circuit 9 becomes the operating energy of the circuit inside the portable device, and the portable device can be activated if a power source of a predetermined level or higher is obtained.

  The communication LF reception antenna 7 receives a communication LF signal including a portable device activation signal transmitted from the LF transmission antenna 1 of the base station. The communication LF reception circuit 8 transmits the communication LF signal received by the communication LF reception antenna 7 to the portable device side control circuit 12. If the communication LF signal transmitted from the base station is encrypted, the LF reception circuit 8 also has a function of decrypting the signal.

  The UHF transmission antenna 10 transmits a UHF response signal, and the UHF transmission circuit 11 generates a UHF response signal.

  The portable device side control circuit 12 controls the operation of the communication LF reception circuit 8, the LF proximity power reception circuit 9, and the UHF transmission circuit 11, and in accordance with the communication LF signal from the communication LF reception circuit 8, Processing such as startup and display on the display is performed. The portable device side control circuit 12 controls the timing so that the UHF response transmission period and the LF reception period do not overlap as in the base station. At this time, it is preferable to consider the spatial propagation delay of the UHF response signal. Specifically, the timing control by the portable device side control circuit 12 is performed corresponding to the timing control by the base station side control circuit 5. This timing control can be realized by controlling using a counter, for example, based on the timing at which the portable device activation signal included in the communication LF signal transmitted from the base station is received by the portable device.

  FIG. 3 is a block diagram showing another embodiment of the base station constituting the proximity power feeding / communication device according to the present invention. In addition, the same code | symbol is attached | subjected to the same or equivalent part as FIG.

  The base station shown in FIG. 1 includes a pair of LF transmission antennas 1 and LF transmission circuits 2 and is configured to be used for both communication and proximity power feeding. The base station shown in FIG. 13, the communication LF transmission circuit 14, the proximity power supply LF transmission antenna 15 and the proximity power supply LF transmission circuit 16, and the communication transmission means and the proximity power transmission means are separated.

  According to this configuration, since a low-impedance antenna can be used as the proximity feeding LF transmission antenna 15, the efficiency of proximity feeding between the base station and the portable device can be increased, and the frequency of the communication LF signal can be increased. The frequency of the LF signal for proximity power feeding can be varied. The configuration and operation of other parts are the same as those in the embodiment of FIG.

  FIG. 4 is a block diagram showing another embodiment of the portable device constituting the proximity power feeding / communication device according to the present invention. In addition, the same code | symbol is attached | subjected to the same or equivalent part as FIG.

  The portable device shown in FIG. 2 has a configuration in which the proximity LF receiving antenna 6 and the communication LF receiving antenna 7 are separately provided. However, the portable device shown in FIG. 4 has one LF receiving antenna 17 for proximity feeding. The configuration is also used for communication.

  If a two-dimensional or three-dimensional antenna is used as the LF reception antenna 17, the proximity power feeding efficiency can be improved by using the power sum received by the plurality of LF antennas and improving the communication reception efficiency due to the directivity of the plurality of antennas. Both improvements can be satisfied together. The configuration and operation of the other parts are the same as in the embodiment of FIG.

  FIG. 5 is a flowchart showing an example of the operation of the proximity power feeding / communication device of the present invention in the base station.

  First, the base station determines whether or not a trigger is given during the base station suspension period (S51). If the base station is powered on, the trigger is given at regular intervals when the communication LF transmission period (TSL) is started. If no trigger is given, wait until a trigger is given. In the case of an entrance / exit management or door control system, the power of the base station may be turned on when a person enters within a certain distance from the base station.

  If a trigger is given during the base station suspension period, the base station first starts operation in the normal communication mode and transmits a communication LF signal to the portable device (S52). The communication LF signal is transmitted within the communication LF transmission period (TSL) (for example, 200 msec), and when the communication LF transmission period (TSL) elapses, the transmission is stopped (S53). After a lapse of a certain time (τsec) after stopping the transmission of the communication LF signal (S54), the base station starts receiving a UHF response signal from the portable device (S55). The period for receiving the UHF response signal is a UHF response reception window period (TRU) (for example, 60 msec). The UHF response reception window period (TRU) is defined by the operable time of the portable device.

  Specifically, the maximum value of the UHF response reception window period (TRU) is the same as the maximum value of the UHF response transmission period (TSU) when considering retransmission of the UHF response signal from the portable device. Further, the fixed time (τsec) may be set to a value equal to or longer than 1 bit of the LF signal (data), for example.

  Next, it is determined whether or not a UHF response signal is received from the portable device within the UHF response reception window period (TRU) (S56). If the base station receives the UHF response signal from the portable device, it is determined in S56 that the UHF response signal has been received, so the base station terminates communication with the portable device and pauses (S58). The base station performs processing and operation according to the received UHF response signal. Here, the operation in the normal communication mode ends.

  If the base station does not receive the UHF response signal from the portable device, it is determined in S56 that no UHF response signal has been received. In this case, the power supply of the portable device is considered exhausted and the proximity power supply mode is entered.

In the proximity power supply mode, first, a proximity power supply LF signal is transmitted from the base station to the portable device (S58). The period during which the proximity power supply LF signal is transmitted is defined by the time until the operating energy of the portable device is secured. For example, the period for transmitting the proximity power feeding LF signal is set to a proximity power feeding LF transmission period T _P (for example, 2 to 3 seconds) in which sufficient power for starting the portable device is obtained by the proximity power feeding. When a certain time (T _P + τ) has elapsed from the transmission of the proximity power feeding LF signal (S59), reception of a UHF response signal from the portable device is started (S60). The period for receiving the UHF response signal is the UHF response reception window period (TRU). The UHF response reception window period (TRU) may be the same as the UHF response reception window period (TRU) in the normal communication mode.

  Next, it is determined whether or not a UHF response signal is received from the portable device within the UHF response reception window period (TRU) (S61). If the base station receives the UHF response signal from the portable device, it is determined in S61 that the UHF response signal has been received, so the base station terminates communication with the portable device and pauses (S62). The base station performs processing and operation according to the received UHF response signal. Here, the operation in the proximity power supply mode ends.

  If the base station does not receive the UHF response signal from the portable device, it is determined in S61 that no UHF response signal has been received. In this state, when the UHF response reception window period (TRU) elapses (S63), the base station pauses (S64). As described above, the base station ends the communication with the portable device and the proximity power feeding.

  FIG. 6 is a time chart showing an example of the operation of the proximity power feeding / communication device of the present invention in the base station. If the base station does not receive the UHF response signal from the portable device, the base station repeats the operation according to this time chart at a constant cycle.

  As shown in FIG. 6, when a trigger is given during the base station suspension period, the base station transmits a communication LF signal. The communication LF signal includes a portable device activation signal. The communication LF signal is transmitted within a communication LF transmission period (TSL) (for example, 200 msec), and the transmission is stopped when the communication LF transmission period (TSL) elapses. Thereafter, when a certain time (τsec) elapses, a UHF response signal from the portable device is waited within a UHF response reception window period (TRU) (for example, 60 msec). The communication LF transmission period (TSL) and the subsequent fixed time (τsec) are the UHF reception stop period. Further, the period from the end of communication LF signal transmission to the elapse of the UHF response reception window period (TRU) is the LF transmission stop period. The above is the operation in the normal communication mode.

If the base station does not receive the UHF response signal from the portable device in the normal communication mode, the base station enters the proximity power supply mode. In the proximity power supply mode, first, a proximity power supply LF signal is transmitted. The proximity power feeding LF signal includes a portable device activation signal at the end portion thereof. Duration of sending proximity feeding LF signal, the portable device is sufficient power to close the feeding LF transmission period T _P obtained by close feed to start.

The proximity power feeding LF transmission period _TP is obtained, for example, by obtaining in advance the time from when the portable device is in an entirely initial state to when the operating energy necessary for starting each part of the portable device is generated. Can do.

When the proximity power supply LF transmission period T _P elapses, transmission of the proximity power supply LF signal is stopped. After that, when a certain time (τsec) elapses, it waits for a UHF response signal from the portable device. The period of waiting for the UHF response signal from the portable device is a UHF response reception window period (TRU) (for example, 60 msec). The LF transmission period (TSL) for proximity power feeding and a fixed time (τsec) thereafter are set as a UHF reception stop period. In addition, the period from the end of transmission of the proximity power feeding LF signal to the elapse of the UHF response reception window period (TRU) is the LF transmission stop period. The above is the operation in the proximity power supply mode.

  FIG. 7 is a time chart showing an example of operation when the base station receives a UHF response signal from the portable device during operation in the normal communication mode in the proximity power supply / communication device of the present invention. This is a case where the portable device can be activated immediately without receiving proximity power supply from the base station.

  The operation of the base station in FIG. 7 is the same as the operation in the normal communication mode in FIG. When a trigger is given in the base station suspension period, the base station transmits a communication LF signal within the communication LF transmission period (TSL). The communication LF signal includes a portable device activation signal.

  When the communication LF transmission period elapses, the transmission of the communication LF signal is stopped. After that, when a certain time (τsec) elapses, the UHF response signal from the portable device is waited within the UHF response reception window period (TRL).

  The mobile device starts immediately after receiving the activation signal included in the communication LF signal from the base station within the LF reception period (TRL) corresponding to the communication LF transmission period (TSL) of the base station, and transmits the communication LF. A UHF response signal is transmitted within the UHF response transmission period (TSU) after a certain time (τsec) from the elapse of the period (TSL).

  The UHF response transmission period (TSU) is defined by the operable time of the portable device. That is, the UHF response transmission period (TSU) is set in advance within a time that does not exceed the time during which the portable device can operate due to the operation energy generated by the proximity power supply from the base station.

  The base station receives the UHF response signal transmitted from the portable device within the UHF response reception window period (TRU). If the transmission / reception in the normal communication mode is successful, the base station and the portable device stop operating there. Note that the communication LF transmission period (TSL) of the base station and the LF reception period (TRL) of the portable device are preferably matched in consideration of the spatial propagation delay of the LF signal. The same applies to other periods.

  FIG. 8 is a time chart showing an example of the operation when the base station does not receive the UHF response signal from the portable device during the operation in the normal communication mode in the proximity power supply / communication device of the present invention. This is a case where the portable device can be activated only after receiving proximity power supply from the base station.

  The operation of the base station in FIG. 8 is the same as the operation in the normal normal communication mode and the proximity power supply mode in FIG. When a trigger is given in the base station suspension period, the base station transmits a communication LF signal within the communication LF transmission period (TSL). The communication LF signal includes a portable device activation signal.

  When the communication LF transmission period (TSL) elapses, transmission of the communication LF signal is stopped, and after a certain time (τsec), the UHF response signal from the mobile device is received within the UHF response reception window period (TRU). wait.

Here, since not receive a UHF response signal from the portable unit, the base station, after further sends an LF signal for Proximity feed in proximity feeding LF within the transmission period T _P, near feeding LF transmission period T _P has passed Stop the transmission. The proximity power feeding LF signal includes a portable device activation signal at the end portion thereof. After that, when a certain time (τsec) elapses, a UHF response signal from the portable device is waited within the UHF response reception window period (TRU).

Portable device is closer powered by communication LF signal from the base station in the LF reception period corresponding to a proximity feeding LF transmission period T _P base stations enabling startup, the end portion of the proximity feeding LF signal It is activated by the included activation signal. Then, after a certain time (τsec), the UHF response signal is transmitted within the UHF response transmission period (TSU).

  The base station receives the UHF response signal transmitted from the portable device within the UHF response reception window period (TSU). If the transmission / reception in the proximity power supply mode is successful, the base station and the portable device stop operating there.

  The above embodiment assumes that there is only one portable device for the base station, but the embodiment when assuming that there are a plurality of portable devices for the base station is as follows. Explained.

  FIG. 9 is a flowchart showing another example of the operation of the proximity power supply / communication device of the present invention in the base station. Here, it is assumed that a plurality of portable devices exist for the base station.

  Since the operation (S91 to S95) from when the base station receives the trigger to when the reception of the UHF response signal from the portable device is started in the normal communication mode is the same as S51 to S55 in FIG. . The period during which the base station receives the UHF response signal from the portable device is the UHF response reception window period (TRU). The UHF response reception window period (TRU) is set in consideration of the timing at which each of the plurality of portable devices transmits a UHF response signal.

  The base station can receive the UHF response signal from the portable device within the UHF response reception window period (TRU) (S96). Here, if there is one or a plurality of portable devices that can be activated immediately without receiving proximity power supply from the base station, the UHF response signal is received within the UHF response reception window period (TRU). Note that collision of responses from a plurality of portable devices can be prevented by using a delay mechanism described later. The base station performs processing and operation according to the received UHF response signal.

  When the UHF response reception window period (TRU) elapses (S96), the base station enters the proximity power supply mode. Since the operation (S97 to S99) from the transmission of the proximity power supply LF signal to the portable device in the proximity power supply mode until the reception of the UHF response signal from the portable device is the same as S58 to S60 in FIG. The description is omitted. The UHF response reception window period (TRU) is also set in consideration of the timing at which each of the plurality of portable devices transmits a UHF response signal. The UHF response reception window period (TRU) may be the same as the UHF response reception window period (TRU) in the normal communication mode.

  The base station can receive the UHF response signal from the portable device within the UHF response reception window period (TRU) (S100). Here, if there is one or a plurality of portable devices that can be activated by receiving proximity power from the base station, the UHF response signal from the mobile device is received within the UHF response reception window period (TRU). Again, collision of responses from a plurality of portable devices can be prevented by using a delay mechanism described later. The base station performs processing and operation according to the received UHF response signal.

  When the UHF response reception window period (TRU) elapses (S100), the UHF response reception window period (TRU) timeout (S101) occurs, and the base station pauses (S102). As described above, the base station ends the communication with the portable device and the proximity power feeding.

5-8, it is assumed that the UHF response signal is transmitted immediately in the UHF response transmission period (TSU) after τ seconds have elapsed since the portable device received the communication LF signal. When it is assumed that there are a plurality of portable devices, it is preferable to consider so that responses from the plurality of portable devices to the communication LF signal transmitted from the base station do not collide. The collision of responses from a plurality of portable devices can be reliably prevented by using a mechanism for transmitting UHF response signals with a delay of T (= TSU) seconds as follows.
This mechanism may be adopted when there is only one portable device.

  FIG. 10 is a time chart illustrating an example of an operation in the normal communication mode in an embodiment in which the delay mechanism is incorporated in a combination of a base station and a plurality of portable devices.

  Each portable device includes a random number generator. This random number generator generates a random number of n = 0 to 15, and each portable device sets the timing of the UHF response transmission period (TSU) according to the value n generated by the random number generator provided by itself to a certain time (TRL + τ ), And set individually in T (= TSU) seconds according to the value n.

  That is, each portable device sets a UHF response transmission period (TSU) after (τ + nT) seconds after the LF reception period (TRL) for communication has passed according to the value n generated by the random number generator provided by itself. Send a UHF response signal. The base station sets the UHF response reception window period (TRU) triggered by the reception of the UHF response signal transmitted from the portable device after (τ + nT) seconds, and the UHF reception circuit within the UHF response reception window period (TRU) To work. The UHF response reception window period (TRU) at the base station may be set to include all response reception window periods of n = 0 to 15. Here, since the timing of the UHF response transmission period (TSU) is defined by a random number, collision of responses from a plurality of portable devices can be prevented.

  FIG. 10 shows the timing of the UHF response transmission period (TSU) and the UHF response reception window period (TRU) when n = 0, n = 2, n = 3, and n = 15. In any case, the base station stops LF transmission in the UHF response reception window period (TRU).

  The delay mechanism described above can also be incorporated in the transmission / reception of the UHF response signal in the proximity power supply mode. That is, each portable device sets the UHF response transmission period (TSU) after (τ + nT) seconds after the LF reception period (TRL) for proximity power feeding has elapsed according to the value n generated by the random number generator provided by itself Then, the UHF response signal is transmitted, and the base station receives the UHF response signal transmitted from the portable device.

  FIG. 11 is an explanatory diagram of a communicable area according to the present invention. In order for the portable device to receive proximity power feeding through the LF transmitting antenna of the base station, like the portable device A, the portable device must be located within the proximity feeding effective area. Further, in order for the portable device to receive the communication LF signal through the LF transmission antenna of the base station, like the portable device B, the portable device must be located in the LF band communication effective area. In the conventional single frequency communication method using the LF band, it is necessary to arrange the reception antenna of the base station within a range where the response signal transmitted from the portable device can be received. The antenna must be placed near the transmitting antenna. However, in the present invention, since the base station receives the response signal from the portable device in the UHF band, the arrangement area of the receiving antenna is not limited to such an area and can be expanded.

  Specifically, the weak LF transmitting antenna and the UHF receiving antenna of the specific low power UHF response signal can be arranged to be separated by about 5 m in the weak wireless system and several tens of meters in the specific low power system.

  As a result, for example, the LF antenna for proximity feeding of the base station is placed on the wall that can be reached by the user, and the UHF receiving antenna that receives the UHF response signal from the portable device is installed on the ceiling, floor, adjacent room, outdoors, etc. It can arrange | position and can raise the freedom degree of an apparatus structure and arrangement | positioning in actualizing an apparatus.

  In addition, as shown in FIG. 11, even if there are a plurality of portable devices A and B in the LF band communication effective area, by operating according to the flowchart of FIG. 9, between the base station and each portable device A and B, Communication can be realized.

  For example, assuming that the battery of the portable device A is consumed and the battery of the portable device B is not consumed, the portable device B immediately transmits a UHF response signal to the base station in the normal communication mode, The portable device A transmits a UHF response signal to the base station after the proximity power supply is performed in the proximity power supply mode.

In the above embodiment, as shown in FIGS. 7 and 8, in the base station, the communication LF transmission period (TSL) and the UHF response reception period (TRU), the proximity power supply LF transmission period _TP and the UHF response reception period ( (TRU) is shifted by τ seconds so that the timing to transmit the LF signal and the timing to receive the UHF response signal do not overlap. It is possible to eliminate spatial sneaking noise.

  As a result, it is possible to prevent the reception of the UHF response signal from the UHF receiving antenna due to the radiated magnetic field of the electromagnetic wave of the LF signal transmitted from the LF transmitting antenna of the base station, and the UHF response transmitted from the portable device. It is possible to prevent signal reception from becoming unstable.

Also in the portable device, communication LF reception period (TRL) and UHF response transmission period (TSU), since proximity feeding LF reception period T _P and UHF response transmission period (TSU) is shifted τ seconds each transmission It is possible to avoid power supply noise that sneaks from the circuit to the receiving circuit and spatial sneaking noise of the transmission electromagnetic wave to the receiving antenna.

  Thereby, it is possible to prevent the reception of the LF signal by the LF reception antenna from being disturbed by the UHF response signal transmitted from the UHF transmission antenna of the portable device. Therefore, the effective communication distance between the base station and the portable device can be maximized, and stable communication can be ensured in a wide area.

  The reception interference at the UHF receiving antenna due to the radiated magnetic field of the electromagnetic wave of the LF signal transmitted from the LF transmitting antenna of the base station is more effective by forming the LF transmitting antenna and the UHF receiving antenna separately from each other. Can be prevented. Specifically, the LF transmitting antenna and the UHF receiving antenna may be formed separately without being formed on the same conductor pattern.

  Although the embodiments have been described above, the present invention is not limited to the above-described embodiments and can be variously modified. For example, in the proximity power supply mode, a short-term proximity power supply LF signal is repeatedly transmitted from the base station a plurality of times, and it is determined whether a UHF response signal is received from the portable device for each transmission, and the UHF response signal is You may make it make a base station and a portable device pause when it receives. In the portable device, when the LF reception period is set again after the UHF response transmission period, an interval before the start of the LF reception period is set so that the transmission UHF response signal does not interfere with the LF reception circuit side and interfere with LF reception. The UHF response transmission period (TSU) may be terminated after an interval (for example, several milliseconds to several tens of milliseconds).

  In addition, in order to ensure security during communication, the base station and the portable device can be provided with the function. To ensure security, for example, one or both of a method for individually identifying a base station and a portable device and a method for encrypting a communication LF signal can be used.

  In the method for individually identifying a base station and a mobile device, individual IDs are assigned to the base station and the mobile device in advance, and communication within the group is enabled based on the ID. To identify a base station belonging to a group capable of communication and a plurality of portable devices, register a combination table of the base station ID and a plurality of portable device IDs in the base station memory and the portable device memory respectively. The base station and the mobile device are individually identified using those IDs.

  Specifically, an LF signal including the base station ID is transmitted from the base station at the time of proximity power feeding. If the base station ID included in the received LF signal is a base station ID in a communicable group including the mobile device, the mobile device starts normally and transmits a UHF response signal including the mobile device ID . If the base station ID is not applicable, the portable device does not respond and does not output unnecessary UHF radio waves. The base station receives the UHF response signal transmitted from the portable device, and recognizes that it is a correct UHF response signal if the included portable device ID is a portable device ID in a communicable group including its own base station.

  In the method of encrypting the communication LF signal, a general rolling code method using an M-sequence counter can be adopted. In the data arrangement of the LF signal to be transmitted and the arrangement / extraction of valid data, the base station and mobile device belonging to the group use unique correspondence and initial values, and the communication LF signal is different from the simple rolling code method. Encryption and decryption may be performed.

  Further, the proximity power feeding system (LF transmitting antenna or LF transmitting circuit) and the communication system (UHF receiving antenna or UHF receiving circuit) in the base station may be separated and arranged at positions separated from each other.

1 ... LF transmitting antenna, 2 ... LF transmitting circuit, 3 ... UHF receiving antenna, 4 ... UHF receiving circuit, 5 ... Base station side control circuit, 6 ... LF for proximity power feeding Reception antenna, 7 ... Communication LF reception antenna, 8 ... Communication LF reception circuit, 9 ... LF proximity power reception circuit, 10 ... UHF transmission antenna, 11 ... UHF transmission circuit, 12・ ・ ・ Mobile device side control circuit, 13 ... Communication LF transmission antenna, 14 ... Communication LF transmission circuit, 15 ... Proximity feeding LF transmission antenna, 16 ... Proximity feeding LF transmission circuit, 17 ... LF receiving antenna

Claims (13)

Proximity power supply from the base station side to the portable device side, and the proximity power supply and communication device that performs communication between the base station and the portable device
The base station has a normal communication mode and a proximity power supply mode. When communicating with a portable device , the base station first transmits a communication LF signal including a portable device activation signal, and transmits the communication LF signal to the communication LF signal from the portable device. Execute the operation in the normal communication mode for receiving the transmitted UHF response signal, and then , after the operation in the normal communication mode, transmit the proximity power feeding LF signal including the portable device activation signal in the terminal portion. A proximity power feeding mode in which an operation is performed in a proximity power feeding mode in which a UHF response signal transmitted to the proximity power feeding LF signal is received from the portable power source that is power- fed by the proximity power feeding LF signal. Communication device. The base station, passing from the portable device in normal communication mode when it does not receive a UHF response signal only near the power feeding and communication apparatus according to claim 1, characterized in that to perform the operation in a close-feed mode.   2. The base station according to claim 1, wherein the base station executes an operation in the proximity power supply mode following the normal communication mode regardless of whether or not a UHF response signal is received from the portable device in the normal communication mode. Proximity feeding / communication device.   Between the transmission period of the communication LF signal and the reception period of the UHF response signal in the base station, between the transmission period of the proximity power feeding LF signal and the reception period of the UHF response signal, and the reception period of the communication LF signal in the portable device 2. A predetermined time interval is provided between the transmission period of the UHF response signal and the transmission period of the proximity power feeding LF signal and the transmission period of the UHF response signal, respectively. 4. The proximity power feeding / communication device according to any one of 3 above.   The period during which the proximity power supply LF signal is transmitted from the base station is defined by the time during which the operating energy is secured in the portable device, and the period during which the UHF response signal is transmitted from the portable device is determined by the portable device. The proximity power feeding / communication device according to claim 1, wherein the proximity power feeding / communication device is defined by a power supply possible time of the operating energy to be secured.   The said portable machine is provided with the capacitor | condenser which stores the energy produced | generated based on the radiation magnetic field which the LF electromagnetic wave of the LF signal for proximity feeding transmitted from the said base station has. The proximity power feeding / communication device described.   The transmission period of the UHF response signal in the portable device and the timing of the reception period of the UHF response signal in the base station with respect to the transmission period are defined according to a random number generated by a random number generator with the transmission period of the UHF response signal as a unit. The proximity power feeding / communication device according to claim 1, wherein:   8. The proximity power supply / communication according to claim 1, wherein the base station includes an LF transmission antenna and an LF transmission circuit that are also used for transmission of a communication LF signal and a proximity power supply LF signal. 9. apparatus.   8. The proximity power supply / transmission circuit according to claim 1, wherein the base station includes a separate LF transmission antenna and an LF transmission circuit for transmitting the communication LF signal and the proximity power supply LF signal. 9. Communication device.   The proximity power supply / communication device according to claim 1, wherein the portable device includes an LF reception antenna that is used for both reception of a communication LF signal and a proximity power supply LF signal.   The proximity power feeding / communication device according to claim 1, wherein the portable device includes separate LF reception antennas for receiving the communication LF signal and the proximity power feeding LF signal.   12. The portable device according to claim 1, wherein the portable device has a function of authenticating the validity of the portable device, and transmits a UHF response signal only when the validity is authenticated. The proximity power feeding / communication device described.   The base station transmits the communication LF signal and the proximity power feeding LF signal by including the base station ID, and based on the base station ID included in the UHF response signal transmitted from the portable device, The portable device authenticates the validity of the portable device based on the base station ID included in the received communication LF signal or the proximity power feeding LF signal, and automatically transmits the UHF response signal to the UHF response signal. The proximity power feeding / communication device according to claim 12, wherein the proximity power feeding / communication device is transmitted including a portable device ID.

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