Signal processing device and searching method

Abstract

To provide a signal processing device that returns a quick response.SOLUTION: A sensor device 200 that is a signal processing device includes: a capacitor 206; a first transmission unit 220 for wirelessly transmitting a first signal SG1 using electric power stored in the capacitor when electric power equal to or more than a prescribed level is stored in the capacitor; a reception unit 210 for receiving radio waves transmitted from a power transmission device 100 that is an external device; and a transmission antenna 22 for, when receiving the radio waves, functioning as a second transmission unit for wirelessly transmitting a response signal SG3 that is a second signal generated based on the received radio waves not using electric power stored in the capacitor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a signal processing device and a search method. [Background technology]

[0002] As an example of a signal processing device, Japanese Patent Application Laid-Open Publication No. 2019-166040 (hereinafter referred to as Patent Document 1) discloses an absorbing member. The absorbing member of Patent Document 1 includes an absorbent body, a pair of electrodes that generate a current when in contact with liquid absorbed by the absorbent body, and a detection device that outputs a signal corresponding to the magnitude of parasitic resistance that changes depending on the size of the non-contact area of ​​the pair of electrodes with the liquid. The absorbing member of Patent Document 1 detects the size of the non-contact area of ​​the electrodes with the liquid. The size of the non-contact area of ​​the electrodes with the liquid can be made to correspond to the remaining spreading capacity of the liquid in the absorbent body. Therefore, the absorbing member of Patent Document 1 is advantageous for understanding the remaining absorption capacity of the absorbent body.

[0003] The absorbent member of Patent Document 1 may be, for example, a diaper, and in this case, the absorbent member of Patent Document 1 can be used to determine when it is time to change the diaper. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-166040 Summary of the Invention

[0005] Since the absorbent member of Patent Document 1 outputs a signal according to the size of the non-contact area between the pair of electrodes and the liquid, there are cases where a signal is not output until the non-contact area reaches a predetermined range. For example, if the absorbent member of Patent Document 1 is a diaper used to determine when it is time to change it, there may be cases where it is desired to determine whether or not the corresponding diaper is present before the timing at which a signal indicating the time to change is output. Therefore, a signal processing device (first signal processing device) that returns a quick response is desired.

[0006] According to one embodiment, a first signal processing device includes a capacitor, a first transmitting unit that, when a predetermined amount of power or more is stored in the capacitor, wirelessly transmits a first signal using the power stored in the capacitor, a receiving unit that receives radio waves transmitted from an external device, and a second transmitting unit that, when the radio waves are received, wirelessly transmits a second signal generated based on the received radio waves without using the power stored in the capacitor.

[0007] When wirelessly transmitting power to a target device (first signal processing device) using a second signal processing device, a directional antenna can be used as the antenna to concentrate transmission power in a specific direction for efficient power transmission. However, when a directional antenna is used, if the power transmission target device (first signal processing device) is located in a direction that deviates from the direction indicated by the directional antenna, the power that the power transmission target device can receive is reduced. For example, if the location of the power transmission target device is difficult to identify because the power transmission target device is buried in a wall, it may be difficult to accurately point the directional antenna toward the location of the power transmission target device. If the power transmission target device is located in a direction that deviates from the direction indicated by the directional antenna, power transmission efficiency may actually decrease. Therefore, a technology for searching the direction of the power transmission target device is desired for efficient power transmission.

[0008] According to one embodiment, the second signal processing device is a signal processing device that outputs a search signal to search for a direction in which a search target device is located, and includes: a directional antenna whose orientation is variable for wirelessly transmitting power to the search target device; a transmission circuit that wirelessly transmits the search signal for searching for the search target device; and a detection circuit that receives a response signal transmitted from the search target device that has received the search signal and outputs a detection signal corresponding to the power of the response signal, and the search signal is transmitted in the direction indicated by the directional antenna whose orientation is variable.

[0009] According to one embodiment, a search method is a method for searching the direction in which a search target device is located, and includes transmitting a search signal in the direction in which the directional antenna is pointed while changing the direction of the directional antenna for wirelessly transmitting power to the search target device, and searching the direction of the search target device based on a response signal transmitted from the search target device that has received the search signal.

[0010] Even if there is a need to check (test) the operation of such a first signal processing device, a signal for causing the device to operate is not necessarily input at the timing at which the test is desired. Therefore, there are cases where the test cannot be performed at the desired timing. In particular, when a signal for causing the device to operate is input only rarely, there is a high possibility that the test cannot be performed at the desired timing. Therefore, there is a demand for a signal processing device (first signal processing device) that can perform a test at the desired timing.

[0011] According to one embodiment, the first signal processing device comprises a signal processing circuit to which an input signal is input, a first generation circuit to generate the input signal, and a second generation circuit configured to generate a pseudo signal of the input signal and provide the pseudo signal to the signal processing circuit, the second generation circuit including a power receiving circuit for receiving wireless power from an external source and configured to generate the pseudo signal using the power received by the power receiving circuit.

[0012] Further details will be described in the following embodiments. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing an overview of a sensor system and the configuration of a sensor device. [Figure 2] FIG. 2 is a schematic diagram showing a specific example of the configuration of a portion of the sensor device. [Figure 3] FIG. 3 is a diagram showing an outline of the configuration of the power transmitting device and the detection signal. [Figure 4] FIG. 4 is a schematic diagram illustrating an example of a power transmission signal and a searching signal transmitted from a power transmitting device. [Figure 5] FIG. 5 is a flowchart showing an example of a method for searching for a direction in which a search target device exists and a method for detecting an abnormality in a sensor device. [Figure 6] FIG. 6 is a diagram showing the configuration of a sensor device used in the inventor's experiment and how to operate a power transmitting device during a search. [Figure 7] FIG. 7 is a diagram showing the measurement results of the reception level of the response signal at the power transmitting device. [Figure 8] FIG. 8 shows the measurement results of the time intervals between sensor signal outputs. DETAILED DESCRIPTION OF THE INVENTION

[0014] <1. Overview of signal processing device and search method>

[0015] (1) A signal processing device (first signal processing device) according to an embodiment includes a capacitor, a first transmitting unit that, when a predetermined amount of power or more is stored in the capacitor, wirelessly transmits a first signal using the power stored in the capacitor, a receiving unit that receives radio waves transmitted from an external device, and a second transmitting unit that, when the radio waves are received, wirelessly transmits a second signal generated based on the received radio waves without using the power stored in the capacitor.

[0016] The second transmitter wirelessly transmits the second signal generated based on the received radio wave without using the power stored in the capacitor, so that the second signal is wirelessly transmitted even when the capacitor does not store a predetermined amount of power. Therefore, when a radio wave is received, the second signal is wirelessly transmitted faster than the first signal. This can increase the response speed of the signal processing device when the second signal is used as a response signal.

[0017] Because the second transmitter wirelessly transmits the second signal generated based on the received radio waves without using the power stored in the capacitor, the second signal is wirelessly transmitted from the signal processing device without using the operation of the signal processing device. Therefore, even if there is an abnormality in the signal processing device, the second signal will be transmitted. As a result, if the second signal is not wirelessly transmitted from the signal processing device even when radio waves are received, it is possible to determine that there is an abnormality in the signal processing device.

[0018] (2) Preferably, the second signal is a harmonic of the radio wave generated in the receiving unit that receives the radio wave, whereby the second signal is emitted when the receiving unit receives the radio wave.

[0019] (3) Preferably, the receiver includes a rectifier circuit that obtains power by rectifying radio waves, and the second signal includes harmonics generated during rectification by the rectifier circuit. This allows the receiver to receive radio waves and rectify them using the rectifier circuit to emit the second signal.

[0020] (4) Preferably, the signal processing device further includes a power generation circuit, and the power generated by the power generation circuit is stored in a capacitor. The first signal is thereby output by the power generated by the power generation circuit. By using the power generation circuit as, for example, a power generation sensor, the signal processing device can be used as a sensor device.

[0021] (5) Preferably, the receiver includes a rectifier circuit that obtains power by rectifying radio waves, and the power obtained by the rectifier circuit is stored in a capacitor. This allows the receiver to obtain power by receiving radio waves from an external device and use it to output the first signal.

[0022] (6) Preferably, the signal processing device further includes a power generation circuit, the rectifier circuit being connected to the capacitor via the power generation circuit, and the power obtained by the rectifier circuit being supplied to the capacitor via a path along which the power generated by the power generation circuit is transmitted. This causes the rectifier circuit to output a second signal, and the power obtained by the rectifier circuit is stored in the capacitor, thereby outputting a first signal. If the first signal is not output even after a period of time has passed since the second signal was output, allowing a predetermined amount of power to be accumulated in the capacitor, an abnormality may have occurred in the signal processing device. Therefore, this configuration makes it possible to detect an abnormality in the signal processing device using the first signal.

[0023] (7) Preferably, the power generating circuit includes an electrode that generates power in the presence of the detection target, and the rectifier circuit is connected to the electrode so that the power obtained by the rectifier circuit is applied to the capacitor via the electrode. This further makes it possible to detect an abnormality in the electrode.

[0024] (8) Preferably, the first transmitter includes a signal processing circuit, and the signal processing circuit is a battery-less circuit that operates using power generated by a power generation circuit as its power source. This simplifies the structure of the processing device and prevents battery-related failures.

[0025] (9) A signal processing device (second signal processing device) according to an embodiment is a signal processing device that outputs a search signal and searches for a direction in which a search target device (first signal processing device) is located, and includes a directional antenna whose orientation is variable for wirelessly transmitting power to the search target device, a transmission circuit that wirelessly transmits the search signal for searching for the search target device, and a detection circuit that receives a response signal transmitted from the search target device that has received the search signal and outputs a detection signal corresponding to the power of the response signal, and the search signal is transmitted in the direction indicated by the directional antenna whose orientation is variable.

[0026] The detection signal output by the detection circuit reports the power of the response signal. Since the search signal is transmitted in the direction pointed by the directional antenna, which has a variable orientation, the direction in which the search target device is located can be searched for according to the power of the response signal, and power can be wirelessly transmitted in the searched direction. This enables efficient power transmission.

[0027] (10) Preferably, the response signal is a harmonic wave generated in the search target device upon receiving the search signal, based on the search signal. This allows the response signal to be returned at the timing of the search target device receiving the search signal, thereby enabling faster search.

[0028] (11) Preferably, the harmonics are generated by rectifying the search signal received by the search target device. This allows the response signal to be returned at the same timing as the search target device rectifies the search signal. This allows for faster search.

[0029] (12) Preferably, the search signal is transmitted from a directional antenna, which allows the search signal to be transmitted wirelessly while changing its direction.

[0030] (13) Preferably, the detection signal includes a first detection signal that changes in accordance with a change in the power level of the response signal. The power level of the response signal is notified by outputting the first detection signal. This makes it possible to search for the direction in which the search target device is located, depending on the direction in which the searching signal was wirelessly transmitted when the response signal with the highest power was received.

[0031] (14) Preferably, the detection signal includes a second detection signal indicating that the power of the response signal has exceeded a predetermined threshold. The output of the second detection signal notifies the user that the power of the response signal has exceeded the predetermined threshold. This allows the user to search for the direction in which the search target device is located, based on the direction in which the search signal was wirelessly transmitted when the power of the response signal exceeded the predetermined threshold.

[0032] (15) Preferably, the signal processing device further includes a controller that switches between a search mode in which a search signal is transmitted and a power transmission mode in which a power transmission signal for transmitting power from the directional antenna is transmitted, the power transmission signal having different power transmission conditions from the search signal, and the controller is configured to switch from the search mode to the power transmission mode when the detection circuit outputs a second detection signal. This allows a search to be performed under power transmission conditions different from those of power transmission, and switches from the search mode to the power transmission mode when the magnitude of the power of the response signal exceeds a predetermined threshold. Therefore, power transmission can be performed after the direction in which the search target device is located is searched for. As a result, power transmission efficiency can be improved.

[0033] (16) Preferably, the signal processing device further includes a controller that switches between a search mode in which a search signal is transmitted and a power transmission mode in which a power transmission signal for transmitting power from a directional antenna is transmitted, the power transmission signal having different power transmission conditions from the search signal, thereby enabling the search to be performed under power transmission conditions different from those of the power transmission.

[0034] (17) Preferably, the controller is configured to adjust the magnitude of the power of the searching signal in accordance with the power transmission conditions, thereby enabling searching to be performed at a power magnitude different from that of the power transmission.

[0035] (18) Preferably, the power transmission condition is one or more conditions selected from the group consisting of a power level, a radio frequency for wireless transmission, antenna characteristics, and a duty ratio. This allows a search to be performed with a power level different from that of the power transmission.

[0036] (19) Preferably, the average transmission power of the search signal is lower than the average transmission power of the power transmission signal. This allows the search to be performed with a power lower than the power transmission.

[0037] (20) Preferably, the search signal is a signal that is transmitted intermittently, and the power transmission signal is a signal that has a larger duty cycle than the search signal. This allows the search to be performed with less power than the power transmission.

[0038] (21) Preferably, the power transmission signal is a continuous wave signal, which allows for efficient power transmission.

[0039] (22) A searching method according to an embodiment is a method for searching the direction in which a search target device (first signal processing device) is located, in which the search target device has a power receiving circuit, and while changing the orientation of a directional antenna for wirelessly transmitting power to the search target device, transmits a search signal in the direction in which the directional antenna is pointing, and searches for the direction of the search target device based on the magnitude of the power of a response signal transmitted from the search target device that has received the search signal.

[0040] Since the search signal is transmitted in the direction pointed by the directional antenna, which has a variable orientation, the direction in which the search target device is located can be searched for according to the power of the response signal, and power can be wirelessly transmitted in the searched direction, enabling efficient power transmission.

[0041] (23) Preferably, the search target device includes a capacitor and a signal processing circuit that wirelessly transmits a sensor signal using the power stored in the capacitor when a predetermined amount of power is stored in the capacitor, and the power obtained when the power receiving circuit receives a power transmission signal is stored in the capacitor. The search method further includes transmitting a power transmission signal for transmitting power from a directional antenna in the searched direction, and determining whether a configuration of the search target device other than the power receiving circuit is normal or abnormal depending on whether a sensor signal is received from the search target device. If a sensor signal is not received after transmitting a power transmission signal to the search target device, it is determined that the search target device is not performing an operation to wirelessly transmit a sensor signal using power obtained by receiving the power transmission signal. This allows the normal or abnormal status of the configuration of the search target device other than the power receiving circuit to be determined.

[0042] (24) A signal processing device (first signal processing device) according to an embodiment includes a signal processing circuit to which an input signal is input, a first generation circuit to generate the input signal, and a second generation circuit configured to generate a pseudo signal of the input signal and provide the pseudo signal to the signal processing circuit, wherein the second generation circuit includes a power receiving circuit for receiving wireless power from an external device and is configured to generate the pseudo signal using the power received by the power receiving circuit. Thus, by receiving wireless power from an external device, the signal processing circuit can perform the same signal processing as when an input signal is input, regardless of the input of the input signal. Therefore, it is possible to test the signal processing in the signal processing circuit at a desired timing.

[0043] (25) Preferably, the second generation circuit is connected to the signal processing circuit via the first generation circuit, and the pseudo signal is provided to the signal processing circuit via a path through which the input signal is transmitted in the first generation circuit, thereby making it possible to detect whether or not there is an abnormality in the first generation circuit.

[0044] (26) Preferably, the first generating circuit includes a power generating element having an electrode that generates power in the presence of the detection target to generate an input signal, and the second generating circuit is connected to the electrode so that the pseudo signal is provided to the signal processing circuit via the electrode. This makes it possible to detect whether or not there is an abnormality in the electrode.

[0045] (27) Preferably, the second generating circuit includes an antenna for receiving microwaves for wireless power supply, and a rectifier for rectifying the microwaves to generate a pseudo signal, thereby enabling the second generating circuit to receive wireless power supply.

[0046] (28) Preferably, the first generating circuit includes a power generating element that generates the input signal by generating power in response to the presence of the detection target, and the signal processing circuit is a battery-less circuit that operates using the input signal as power source. This makes it possible to detect the presence or absence of an abnormality in the first generating circuit regardless of the presence or absence of the detection target.

[0047] (29) Preferably, the signal processing circuit wirelessly transmits a first signal from the first antenna when an input signal or a pseudo signal is provided, thereby enabling the signal processing device to be used as a sensor for detecting the input signal.

[0048] (30) Preferably, the signal processing device further includes a second antenna for wirelessly transmitting a second signal generated based on the received radio wave for wireless power supply, thereby outputting the second signal as a response signal in response to the reception of the radio wave for wireless power supply.

[0049] (31) Preferably, the second signal is a harmonic of the radio wave generated in the power receiving circuit that receives the radio wave. This makes it possible to output the harmonic generated by receiving the radio wave for wireless power supply as the second signal without installing a circuit for generating the second signal.

[0050] (32) Preferably, the power receiving circuit includes a rectifier circuit that obtains power by rectifying radio waves, and the second signal includes harmonics generated during rectification by the rectifier circuit. This makes it possible to output the harmonics generated by receiving and rectifying the radio waves as the second signal without incorporating a circuit for generating the second signal.

[0051] 2. Examples of signal processing devices and search methods

[0052] 1, 2, and the upper diagram of Fig. 3 show an example of the configuration of a sensor system 1 according to this embodiment. The sensor system 1 includes a sensor device 200, which is an example of a first signal processing device, and a power transmitting device 100, which is an example of a second signal processing device.

[0053] The sensor device 200 senses a sensing target and outputs a signal indicating the sensing result. Preferably, the sensor device 200 generates power through the sensing operation and operates using the generated power. The power transmitting device 100 wirelessly transmits power to the sensor device 200. The sensor device 200 operates using the power supplied from the power transmitting device 100. This makes the sensor device 200 preferably a battery-less circuit.

[0054] The power transmitting device 100 detects the direction in which the sensor device 200 is located, with the sensor device 200 being the search target device, thereby enabling efficient power transmission.

[0055] Preferably, the power transmitting device 100 detects an abnormality in the sensor device 200. This makes it possible to detect an abnormality in the sensor device 200 and take action even when the power transmitting device 100 is located far from the sensor device 200 or in a location that is difficult to check.

[0056] The sensor device 200 is a device that detects the presence of liquid using a water-filled battery. One example of the sensor device 200 is a water leak sensor. The sensor device 200 includes a sensor unit 220. A first antenna 23 is connected to the sensor unit 220. The sensor unit 220 functions as a first transmission unit that outputs a sensor signal (first signal) SG1 from the first antenna 23.

[0057] The sensor unit 220 includes a power generation circuit 205. The power generation circuit 205 includes a pair of electrodes 205A, 205B, and functions as a flooded battery. The sensor unit 220 includes a capacitor 206. The capacitor 206 is connected to the power generation circuit 205. The power generated by the power generation circuit 205 is supplied to the capacitor 206 via a conductor L2. As a result, the power generated by the power generation circuit 205 is stored in the capacitor 206.

[0058] Electrodes 205A and 205B function as a positive electrode and a negative electrode, respectively. Electrodes 205A and 205B generate electricity when in contact with a liquid present between the electrodes. Power generation circuit 205 detects the presence of a liquid between electrodes 205A and 205B based on the power generated by electrodes 205A and 205B.

[0059] The sensor unit 220 includes a signal processing circuit 207. An input signal is input to the signal processing circuit 207, and the signal processing circuit 207 performs processing to wirelessly transmit a sensor signal SG1 from the first antenna 23 using the input signal.

[0060] A capacitor 206 is connected to a power supply terminal of the signal processing circuit 207. The signal processing circuit 207 operates using the capacitor 206 as its operating power supply. The signal processing circuit 207 monitors the charging voltage of the capacitor 206.

[0061] A wireless transmitter 208 is connected to the signal processing circuit 207. The wireless transmitter 208 performs wireless communication with the receiver 300. The wireless communication is, for example, Bluetooth (registered trademark) or Bluetooth Low Energy (registered trademark).

[0062] When signal processing circuit 207 detects that the charging voltage of capacitor 206 has reached set voltage Vt, it supplies the power charged in capacitor 206 to wireless transmitter 208. Set voltage Vt is a threshold value that is set in advance as a driving condition of wireless transmitter 208. That is, signal processing circuit 207 receives, as an input signal, a power signal based on the power charged in capacitor 206. As a result, sensor signal SG1 is output from wireless transmitter 208.

[0063] When the signal processing circuit 207 consumes the power of the capacitor 206 by supplying it to the wireless transmitter 208, the potential of the capacitor 206 drops. As a result, the signal processing circuit 207 stops operating. This stops the supply of power to the wireless transmitter 208. If the power generation circuit 205 is generating power, the capacitor 206 is charged again.

[0064] As long as the power generation circuit 205 is generating power, the capacitor 206 repeatedly charges and discharges. In other words, the power generation circuit 205 functions as a first generation circuit that generates an input signal to be input to the signal processing circuit 207. Accordingly, the sensor signal SG1 output from the wireless transmitter 208 becomes an intermittent output having a time interval H. The sensor signal SG1 output from the wireless transmitter 208 becomes a detection signal that indicates the detection of a water leak.

[0065] The time interval H between outputs of the sensor signal SG1 depends on the charging speed of the capacitor 206. The charging speed increases as the amount of power generated by the power generation circuit 205 increases. Therefore, the time interval H decreases as the amount of power generated by the power generation circuit 205 decreases, and decreases as the amount of power generated decreases.

[0066] The more electrodes 205A, 205B are in contact with the liquid, the greater the amount of electricity generated. Therefore, by installing electrodes 205A, 205B at a location where water leakage is monitored, for example, at a position where the amount of liquid present between electrodes 205A, 205B increases as the water level rises, water leakage can be detected based on the time interval H. For example, by measuring the time interval H of the output of sensor signal SG1, water leakage can be detected when it becomes shorter than a preset threshold.

[0067] The sensor signal SG1 is received by a receiver 300. The receiver 300 is a device carried by a monitor, and is, for example, a terminal device such as a smartphone, which allows water leakage to be monitored remotely.

[0068] The sensor device 200 includes a receiving unit 210. A receiving antenna 21 is connected to the receiving unit 210. The receiving antenna 21 receives radio waves, which are microwaves, transmitted from the power transmitting device 100. The receiving unit 210 includes a power receiving circuit 211 for receiving wireless power from the power transmitting device 100. The power receiving circuit 211 includes a rectifier circuit 212 that obtains power by rectifying the radio waves received by the receiving antenna 21.

[0069] Rectifier circuit 212 includes, for example, diode 201, filter 202, and capacitor 204. Diode 201 rectifies radio waves received from receiving antenna 21 and converts them into DC power. The DC power is provided to filter 202. Filter 202 has a function of removing pulsating current, which is a harmonic component, as noise, and is, for example, a band elimination filter (BEF) or a low pass filter (LPF). Filter 202 removes high-frequency noise from the DC power provided by diode 201. The DC power from which noise has been removed by filter 202 is temporarily stored in capacitor 204.

[0070] The power receiving circuit 211 is connected to the sensor unit 220 via the conductor L1. As a result, the power obtained by the power receiving circuit 211 is provided to the sensor unit 220 via the conductor L1. That is, the radio waves received as power by the receiving antenna 21 are supplied to the sensor unit 220 as DC power. The power supplied via the conductor L1 is provided to the capacitor 206 in the sensor unit 220 via the conductor L2. As a result, the power obtained by the rectifier circuit 212 is provided to the signal processing circuit 207.

[0071] The signal processing circuit 207 causes the sensor device 200 to function as a sensor by wirelessly transmitting the sensor signal SG1 using the power generated by the power generation circuit 205. By charging the capacitor 204 with the power received by the receiving unit 210 as well, the signal processing circuit 207 performs processing to wirelessly transmit the sensor signal SG1 using the received power as well. In other words, the signal processing circuit 207 does not distinguish between the received power and the power generated by the power generation circuit 205, and performs processing to wirelessly transmit the sensor signal SG1 regardless of whether either is received. Therefore, if the power provided by the power generation circuit 205 is considered to be an input signal, the power provided by the receiving unit 210 corresponds to a pseudo signal that simulates the input signal.

[0072] The receiving unit 210 functions as a second generating circuit configured to generate a pseudo signal of the input signal and provide the pseudo signal to the signal processing circuit 207. The receiving unit 210 functioning as the second generating circuit includes a power receiving circuit 211 for receiving wireless power from an external source, and is configured to generate the pseudo signal using the power received by the power receiving circuit 211.

[0073] The power receiving circuit 211 is connected to the sensor unit 220 at a position where the received power is applied to the capacitor 206 via a conductor L2. As an example, the conductor L1 from the power receiving circuit 211 may be connected to the conductor L2 that connects the electrodes 205A, 205B and the capacitor 206, as shown at a position P2 in FIG.

[0074] As a result, the power received by the power receiving circuit 211 is provided to the capacitor 206 via the conductor L2. Therefore, the pseudo signal is provided to the signal processing circuit 207 via the same path as the input signal. This makes it possible to use the pseudo signal to cause the signal processing circuit 207 to perform the same operation as when an input signal is input, thereby determining whether the sensor device 200 is normal or abnormal.

[0075] Preferably, conductor L1 from power receiving circuit 211 is connected onto electrodes 205A and 205B. More preferably, conductor L1 is connected to the ends of electrodes 205A and 205B farther from capacitor 206, which is indicated by position P1 in FIG. 2. This allows a pseudo signal to be input to signal processing circuit 207 via electrodes 205A and 205B. This makes it possible to determine whether electrodes 205A and 205B are normal or abnormal.

[0076] The sensor device 200 has a second antenna 22. The second antenna 22 functions as a second transmitting unit. Harmonics are generated by the rectification operation performed in the rectifier circuit 212. The generated harmonics are radiated into space from the second antenna 22 as a response signal SG3 (second signal).

[0077] As an example, the receiving antenna 21 and the second antenna 22 may form a dipole antenna. Alternatively, as another example, the receiving antenna 21 and the second antenna 22 may be a monopole antenna having only one of the antenna elements.

[0078] The power transmitting device 100 includes a PLL (Phase Locked Loop) 106. The PLL 106 generates and outputs a signal SG2 of a predetermined frequency from a power supply (not shown). The predetermined frequency is, for example, 2.45 GHz.

[0079] The power transmitting device 100 has a transmitting antenna 11, and wirelessly transmits a signal SG2 from the transmitting antenna 11 to the sensor device 200. The transmitting antenna 11 has a length according to the frequency of the signal SG2.

[0080] The transmitting antenna 11 is a directional antenna whose direction can be changed. The power transmitting device 100 detects the direction in which the sensor device 200 is located, with the sensor device 200 being the device to be searched for, and transmits power by pointing the transmitting antenna 11 in the direction in which the sensor device 200 is located. This enables efficient power supply.

[0081] The power transmitting device 100 includes a controller 101, which is a signal processing circuit. The controller 101 is connected to a switch 102 and controls the ON / OFF of the switch 102. The switch 102 is connected to a PLL 106. As a result, the timing at which the signal SG2 is transmitted from the transmitting antenna 11 is controlled by the controller 101.

[0082] The power transmitting device 100 includes a receiving antenna 12 that receives the response signal SG3. The receiving antenna 12 has a length that corresponds to the frequency of the response signal SG3. Specifically, the receiving antenna 12 has a length that resonates with the frequency of the response signal SG3. The response signal SG3 is a harmonic having a frequency that is a multiple of the fundamental wave of the signal SG2.

[0083] Preferably, the harmonic is a second harmonic having a frequency twice that of the signal SG2. The higher the frequency of a harmonic, the weaker its energy becomes. Therefore, by receiving the second harmonic, which has the highest energy among the harmonics, the high-energy harmonic can be used for the signal processing described below.

[0084] When the frequency of the signal SG2 is 2.45 GHz, the transmitting antenna 11 has a length corresponding to 2.45 GHz. When the response signal SG3 is the second harmonic, the frequency is 4.9 GHz, and the receiving antenna 12 has a length corresponding to the 4.9 GHz electromagnetic wave, which is shorter than that of the transmitting antenna 11.

[0085] The power transmitting device 100 includes a receiving circuit 103. The receiving circuit 103 functions as a receiver that processes a response signal SG3 received by a receiving antenna 12. The received response signal SG3 is converted into a digital signal by an AD converter (ADC) 104 and provided to a detection circuit 105.

[0086] The detection circuit 105 detects the power level of the input response signal SG3 and outputs a first detection signal SG41 that indicates the power level. The power of the first detection signal SG41 changes depending on the power level of the response signal SG3. In other words, the power of the first detection signal SG41 is greatest when the power of the response signal SG3 is greatest.

[0087] The lower diagram of Fig. 3 is a diagram showing an overview of the first detection signal SG41, and shows the change in power of the first detection signal SG41 with the change in angle of the receiving antenna 12 when the response signal SG3 is received while changing the angle of the receiving antenna 12. The vertical axis of the lower diagram of Fig. 3 represents signal strength, and the horizontal axis represents angle. In the example of the lower diagram of Fig. 3, the power of the first detection signal SG41 is maximum when the angle of the receiving antenna 12 is angle θ. This allows us to infer that the direction of angle θ at which the receiving antenna 12 faces is the direction in which the sensor device 200, the device to be searched, is located.

[0088] The first detection signal SG41 may be provided to an output device and used to generate an output indicating the magnitude of the power of the response signal SG3. As an example, the first detection signal SG41 may be provided to a display and used as a signal to display a graph such as the one shown in the lower diagram of FIG. 3. As another example, the first detection signal SG41 may be provided to a speaker and used to output audio at a frequency corresponding to the magnitude of the power of the response signal SG3. This makes it possible to determine the angle θ of the receiving antenna 12 at which the power of the response signal SG3 is maximized, i.e., the direction in which the sensor device 200 is located, from the first detection signal SG41.

[0089] The detection circuit 105 may detect the power level of the input response signal SG3 and output a second detection signal SG42 representing the result of comparison with a preset threshold. The second detection signal SG42 is, for example, a signal indicating that the power level of the response signal SG3 has exceeded the threshold.

[0090] The signal SG2 transmitted from the transmitting antenna 11 includes a power transmission signal SG21 and a search signal SG22. The controller 101 has a power transmission mode and a search mode as modes for transmitting the signal SG2 from the transmitting antenna 11. The power transmission mode is a mode in which the power transmission signal SG21 is transmitted from the transmitting antenna 11. The search mode is a mode in which the search signal SG22 is transmitted from the transmitting antenna 11.

[0091] The power transmission signal SG21 and the search signal SG22 are signals with different power transmission conditions. The power transmission condition is a condition that the average transmission power of the search signal SG22 is smaller than the average transmission power of the power transmission signal SG21. As an example, the power transmission signal SG21 and the search signal SG22 have different duty ratios. The duty ratio of the search signal SG22 is smaller than that of the power transmission signal SG21.

[0092] FIG. 4 is a schematic diagram illustrating an example of the power transmission signal SG21 and the search signal SG22, showing the change in power over time of the power transmission signal SG21 and the search signal SG22. In the example of FIG. 4, both the power transmission signal SG21 and the search signal SG22 have sine waves, and the amplitude A and the period B, which is the time between peaks of the amplitude, are equal. The power transmission signal SG21 is a continuous wave signal, and a sine wave is continuous. The search signal SG22 is a signal that transmits a sine wave intermittently, and is a signal that repeats, for every period t1, an ON period t2 during which the sine wave is continuous and an OFF period (t1-t2) during which the sine wave is stopped. The duty ratio t2 / t1 of the search signal SG22 is smaller than the duty ratio 1 of the power transmission signal SG21. In other words, the power transmission signal SG21 is a signal with a larger duty ratio than the search signal SG22.

[0093] To make the duty ratios of the power transmission signal SG21 and the search signal SG22 different, the controller 101 makes the ON / OFF timing of the switch 102 different between the power transmission mode and the search mode. In the example of FIG. 4, the controller 101 keeps the switch 102 ON in the power transmission mode. This causes the power transmission signal SG21, which is a continuous wave signal, to be output. In the search mode, the controller 101 turns the switch 102 ON / OFF so that the duty ratio is t2 / t1. This causes the search signal SG22 to be intermittently output with the duty ratio t2 / t1.

[0094] The radio wave strength when the searching signal SG22 is transmitted is set to be approximately the same as the radio wave strength of the power transmission signal SG21. In this way, by transmitting the searching signal SG22 intermittently, it is possible to reduce power consumption during searching without reducing the radio wave strength of the response signal SG3.

[0095] As another example, the power transmission condition is one or more conditions selected from the group consisting of the magnitude of power, the radio frequency for wireless transmission, and the duty ratio. That is, the search signal SG22 may be a signal with lower power than the power transmission signal SG21. Also, the search signal SG22 may be a signal with a lower frequency than the power transmission signal SG21. Furthermore, the power transmission condition may be a combination of these.

[0096] Instead of the controller 101 controlling the switching of the power transmission conditions between the power transmission mode and the search mode, the transmitting antenna 11 may include an antenna element for transmitting the search signal SG22 and an antenna element for transmitting the power transmission signal SG21, and the controller 101 may switch the antenna element used for transmission.

[0097] This allows the average transmission power of the searching signal SG22 to be smaller than the average transmission power of the power transmission signal SG21. As a result, the electrical energy of the searching signal SG22 can be made smaller than the electrical energy of the power transmission signal SG21.

[0098] Preferably, the second detection signal SG42 is input from the detection circuit 105 to the controller 101. When the controller 101 receives the input of the second detection signal SG42, it switches from the search mode to the power transmission mode. As a result, the controller 101 switches to the power transmission mode after searching the direction in which the sensor device 200, which is the device to be searched for, is located. As a result, it becomes possible to transmit the power transmission signal SG21 by pointing the transmitting antenna 11 in the direction in which the sensor device 200 is located, thereby improving power transmission efficiency.

[0099] 5 is a flowchart showing an example of a method for searching the direction in which the sensor device 200, which is a search target device, is located, using the power transmitting device 100, and a method for detecting an abnormality in the sensor device 200. As an example, the search for the sensor device 200 is performed prior to transmitting power to the sensor device 200. This allows the transmitting antenna 11, which is a directional antenna, to be directed in the direction in which the sensor device 200 is located and transmits the power transmission signal SG21.

[0100] As another example, the search for the sensor device 200 is performed when detecting an abnormality in the sensor device 200. The power transmitting device 100 transmits a power transmission signal SG21 from the transmitting antenna 11 in the direction of the searched sensor device 200, and detects an abnormality in the sensor device 200 using the response signal SG3.

[0101] As an example of the search, the user of the power transmitting device 100 searches for the direction of the sensor device 200 while changing the direction of the variable-direction transmitting antenna 11. The user can determine the direction of the sensor device 200 based on the detection result from the power transmitting device 100.

[0102] Instead of a user, a processing device may be connected to the power transmitting device 100, and the processing device may perform a series of searches. In this case, the transmitting antenna 11 is connected to a driving device, and the driving device can change its direction under the control of the processing device. Then, the processing device determines the direction in which the sensor device 200 is located based on the detection result from the power transmitting device 100.

[0103] 5, first, the controller 101 switches to a search mode (step S101) and causes the transmitting antenna 11 to output a search signal SG22 (step S103). At this time, the user or the processing device continuously changes the direction of the transmitting antenna 11. As an example, the transmitting antenna 11 may be rotated 360° in a horizontal plane, or the transmitting antenna 11 may be rotated 360° in a vertical plane. As a result, the search signal SG22 is transmitted in each direction.

[0104] When the receiving circuit 103 receives the response signal SG3 (YES in step S105), the detecting circuit 105 outputs a first detection signal SG41 that indicates the magnitude of the power of the received response signal SG3 (step S107).

[0105] The detection circuit 105 compares the power of the received response signal SG3 with a pre-stored threshold, and if it is less than the threshold (NO in step S109), it does not output the second detection signal SG42. As a result, the first detection signal SG41 indicating the power of the response signal SG3 is continuously output, as shown in the lower graph of Fig. 3, until the power of the response signal SG3 becomes equal to or greater than the threshold. By rotating the transmitting antenna 11 at this time, the power of the response signal SG3 in each direction can be known from the first detection signal SG41.

[0106] If the power of the received response signal SG3 is equal to or greater than the threshold (YES in step S109), the detection circuit 105 outputs a second detection signal SG42 indicating the result (step S111). This allows the direction of the transmitting antenna 11 at that time to be known as the direction in which the sensor device 200 is located.

[0107] The second detection signal SG42 is input from the detection circuit 105 to the controller 101. When the second detection signal SG42 is input, the controller 101 switches from the search mode to the power transmission mode (step S113). By this switching, the controller 101 turns the switch 102 to the OFF state. As a result, the power transmission signal SG21 is output from the transmitting antenna 11 (step S115).

[0108] In step S115, the direction of the transmitting antenna 11 when outputting the power transmission signal SG21 is set to the direction in which it was detected in step S109 that the power of the response signal SG3 is equal to or greater than the threshold value. This allows power to be transmitted intensively in the direction of the sensor device 200, thereby improving power transmission efficiency.

[0109] In the above search, by using the response signal SG3 instead of the sensor signal SG1 from the sensor device 200, the search can be performed more quickly than when using the sensor signal SG1. This is because it is necessary to wait for the charge of the capacitor 206 to reach the set voltage Vt before the sensor signal SG1 can be output. Therefore, it becomes possible to detect the magnitude of the power of the response signal SG3 while continuously rotating the transmitting antenna 11.

[0110] Once the direction in which the sensor device 200 is located has been searched for, it is preferable to detect an abnormality in the sensor device 200. Specifically, if the receiver 300 receives the sensor signal SG1 within a specified time after the power transmission signal SG21 is output in step S115 (YES in step S117), the sensor device 200 is determined to be normal (step S121). This is because it is known that the sensor device 200 operates in the same way as when it uses the power generated by the power generation circuit 205 due to the power supply from the power transmission device 100, and the sensor signal SG1 is output.

[0111] If the sensor signal SG1 is not received by the receiver 300 even after the specified time has elapsed (NO in step S117 and YES in step S119), it is determined that there is an abnormality in the components of the sensor device 200 other than the receiving unit 210 (step S123). This is because although power was received by the receiving unit 210 of the sensor device 200, the sensor signal SG1 was not output using the received power. This makes it possible to determine that there is an abnormality in the components of the sensor device 200 other than the receiving unit 210.

[0112] The inventors conducted an experiment to verify the searching method according to the embodiment. In the experiment, a composite Yagi-Uda antenna consisting of a transmitting antenna 11 having a length corresponding to 2.45 GHz and a receiving antenna 12 having a length corresponding to 4.9 GHz was used as the antennas 11 and 12 of the power transmitting device 100. Each of the antennas 11 and 12 has eight conductors, and the boom lengths are 30 cm and 15 cm, respectively. The maximum antenna gain of the transmitting antenna 11 is 15.74 dBi, and the maximum antenna gain of the receiving antenna 12 is 12.74 dBi.

[0113] As another example of the antennas 11 and 12 of the power transmitting device 100, a single antenna may be used in which an antenna element having a length corresponding to 2.45 GHz and an antenna element having a length corresponding to 4.9 GHz are connected in series. This is because the direction in which the power transmission signal SG21 is transmitted matches the direction in which the response signal SG3 is received. This can reduce the antenna area and suppress mutual influence between the antennas 11 and 12.

[0114] The antennas 21, 22 of the sensor device 200 consisted of a receiving antenna 21, which was a sleeve antenna with a length corresponding to 2.45 GHz, and a second antenna 22, which was a dipole antenna with a length corresponding to 4.9 GHz. The boom length of the receiving antenna 21 was 3 cm, and the boom length of the second antenna 22 was 6 cm. The maximum antenna gain of the receiving antenna 21 was 2.14 dBi, and the maximum antenna gain of the second antenna 22 was 2.04 dBi.

[0115] 6 is a diagram showing the configuration of the sensor device 200 used in the experiment and how to operate the power transmitting device 100 during search. The sensor device 200 has a receiving unit 210 connected to one end of electrodes 205A and 205B, and antennas 21 and 22. The power transmitting device 100 was located 1 m away from the sensor device 200.

[0116] The power transmitting device 100 was rotated 360° in a horizontal plane at a position 1 m away from the sensor device 200, as shown by arrow C in Fig. 6, and the reception level of the response signal SG3 from the sensor device 200 was measured at each position. The rotation was performed over 4 seconds per 360°. In the search mode, the search signal SG22 was transmitted intermittently with a period t1 of 552 ms and a duty ratio t2 / t1 of 0.087.

[0117] 7 is a diagram showing the measurement results of the reception level of the response signal SG3 from the sensor device 200 at the power transmitting device 100. The angle around the origin in Fig. 7 represents the rotation angle of the power transmitting device 100, and the values ​​on the X-axis and Y-axis represent the reception level.

[0118] 7, it was found that, when the detection level required for position detection was set to 4.9 dBm for the antennas of the power transmitting device 100 and the sensor device 200 used in the experiment, the direction of the sensor device 200 could be detected within a range of ±20° from the angle of 90° at which the maximum gain was obtained. Since the search signal SG22 was transmitted with a duty ratio t2 / t1 of 0.087, it was found that the direction of the sensor device 200 could be detected with 1 / 10 the power compared to the power transmission signal SG21 transmitted as a continuous signal. It was also found that the direction of the sensor device 200 could be detected even at a rotation speed of 360° in 4 seconds.

[0119] Furthermore, using the above-mentioned power transmission device 100 and sensor device 200, the inventors changed the position of the power transmission device 100 relative to the sensor device 200 and measured the time interval H of the output of the sensor signal SG1 output from the sensor device 200 in response to the transmission of the power transmission signal SG21 from the power transmission device 100.

[0120] Fig. 8 is a diagram showing the measurement results of the time interval H of the output of the sensor signal SG1. The vertical axis of Fig. 8 represents the time interval H, and the horizontal axis represents the distance of the power transmitting device 100 from the sensor device 200. The measurement results of Fig. 8 show that when the distance of the power transmitting device 100 from the sensor device 200 is within 120 cm, the time interval H is 10 seconds or less, and when the distance exceeds 120 cm, the time interval H increases rapidly.

[0121] From this result, it was found that the power transmission device 100 can detect an abnormality in the sensor device 200 if the distance between the power transmission device 100 and the sensor device 200 is within 120 cm. This shows that even if the sensor device 200 does not have a power supply for abnormality detection and is battery-less, it is possible to monitor an abnormality by using the power transmission device 100.

[0122] <3. Notes> The present invention is not limited to the above-described embodiment, and various modifications are possible. [Explanation of symbols]

[0123] 1: Sensor system 11: Transmitting antenna 12: Receiving antenna 21: Receiving antenna 22: Second antenna 23: First antenna 100: Power transmission device 101: Controller 102: Switch 103: Receiving circuit 105: Detection circuit 106: PLL 200: Sensor device 201: Diode 202: Filter 204: Capacitor 205: Power generation circuit 205A: Electrode 205B: Electrode 206: Capacitor 207: Signal processing circuit 208: Radio transmitter 210: Receiving unit 211: Receiving circuit 212: Rectifier circuit 220: Sensor section 300: Receiver A: Amplitude B :Period C: Arrow H: Time interval L1: Conductor L2: Conductor SG: Sensor signal SG1: Sensor signal SG2: Signal SG21: Power transmission signal SG22: Search signal SG3: Response signal SG41: First detection signal SG42: Second detection signal

Claims

1. A capacitor; When a predetermined amount of power or more is stored in the capacitor, a first transmitter that wirelessly transmits a first signal using the power stored in the capacitor; a receiving unit that receives radio waves transmitted from an external device; a second transmitting unit that, upon receiving the radio wave, wirelessly transmits a second signal generated based on the received radio wave without using the power stored in the capacitor; a power generation circuit, the second signal is a harmonic of the radio wave generated in a receiving unit that receives the radio wave, the receiving unit includes a rectifier circuit that is connected to the capacitor via the power generation circuit and obtains power by rectifying the radio waves; The power obtained by the rectifier circuit is supplied to the capacitor via the path through which the power generated by the power generating circuit is transmitted. Signal processing device.

2. The power generation circuit includes an electrode that generates electricity in the presence of an object to be detected, The rectifier circuit is connected to the electrodes so that the power obtained by the rectifier circuit is applied to the capacitor via the electrodes. The signal processing device according to claim 1 .

3. The second signal includes harmonics generated during rectification by the rectifier circuit.

3. The signal processing device according to claim 1 or 2.

4. The first transmitter includes a signal processing circuit, The signal processing circuit is a battery-less circuit that operates using the power generated by the power generation circuit as power supply power. The signal processing device according to any one of claims 1 to 3.

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