Closed space sensor system and method of operating the closed space sensor system

Abstract

To provide a closed space sensor system for which the stable operation is possible in a closed space.SOLUTION: A closed space sensor system comprises: a power transmission unit 40 of an electromagnetic wave irradiation device 140 which radiates electromagnetic waves; and a plurality of sensors 30A, 30B, 30C... each of which comprises an antenna, and converts the electromagnetic waves received by the antenna into power to be driven. Each of the plurality of sensors comprises a power storage unit, and starts drive when a power storage amount in the power storage unit reaches a drive starting threshold common to the plurality of sensors. In addition, the power transmission unit of the electromagnetic wave irradiation device and the plurality of sensors are arranged in a closed space.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a confined space sensor system and a method of operating a confined space sensor system. [Background technology]

[0002] In closed spaces such as rooms, storage facilities, chambers, tanks, and furnaces, multiple sensors may be placed to measure the distribution of environmental conditions such as temperature and humidity within the closed space, and to monitor the presence and movement of multiple items placed within the closed space, for the purpose of quality control and traceability (see, for example, Patent Documents 1 and 2).

[0003] Traditionally, sensors have been powered by wires and have transmitted and received data by wires. However, in recent years, wireless sensors that transmit and receive data wirelessly have become widespread. Wireless sensors have the advantages of not requiring wiring, being able to be placed in locations where wiring is physically difficult, and not causing wiring defects that can occur due to contact between wiring and objects, etc. The advantage of not requiring complex wiring is considered to be particularly significant when multiple sensors need to be placed.

[0004] There are two types of wireless sensors: those that are powered by wires and those that are powered wirelessly. Wired power supply does not take advantage of the advantage of wireless sensors, which is that they do not require wiring. Therefore, wireless sensors that are powered wirelessly are attracting attention. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 123062 [Patent Document 2] JP 2019-88128 A Summary of the Invention [Problem to be solved by the invention]

[0006] According to the knowledge of the inventor, when multiple wireless sensors are operated simultaneously, communication quality may decrease and operation may become unstable. Therefore, one of the objects of the present invention is to provide a closed space sensor system and an operation method of the closed space sensor system capable of stable operation in a closed space. [Means for solving the problem]

[0007] According to an aspect of the present invention, there is provided a closed space sensor system comprising: a power transmission unit of an electromagnetic wave irradiation device that irradiates electromagnetic waves; and a plurality of sensors, each of which has an antenna and converts the electromagnetic waves received via the antenna into electricity to operate, each of the plurality of sensors having a power storage unit, and when the amount of stored power in the power storage unit reaches a common operation start threshold value for the plurality of sensors, each of the plurality of sensors starts operating, and the power transmission unit of the electromagnetic wave irradiation device and the plurality of sensors are disposed within a closed space.

[0008] In the above-described closed space sensor system, the receiving sensitivity of at least some of the multiple sensors may differ within the closed space.

[0009] In the above-described closed space sensor system, the peak of reception sensitivity of at least some of the multiple sensors may be able to fall outside the transmission frequency range of the electromagnetic waves that can be irradiated by the power transmitting section of the electromagnetic wave irradiating device.

[0010] In the closed space sensor system described above, when the amount of stored power in the power storage unit reaches a drive start threshold common to the plurality of sensors, each of the plurality of sensors may start driving and wirelessly transmit a sensing signal.

[0011] In the above-described closed space sensor system, the plurality of sensors may have the same measurement period.

[0012] In the closed space sensor system, each of the multiple sensors may include a transmitter that transmits a sensing signal in a transmission cycle via an antenna, and a random number assigning unit that generates a random number and assigns the random number to the transmission cycle. The antenna that transmits the sensing signal may be the same as or different from the antenna that receives the electromagnetic wave converted into electric power.

[0013] In the closed space sensor system, each of the plurality of sensors may further include a transmitter that transmits a sensing signal on at least one of a plurality of signal transmission frequency channels via an antenna. The antenna that transmits the sensing signal may be the same as or different from the antenna that receives the electromagnetic wave converted into electric power.

[0014] The closed space sensor system may further include a plurality of sensing signal receiving devices for receiving sensing signals.

[0015] In the above-mentioned closed space sensor system, the power transmitting section of the electromagnetic wave irradiating device may irradiate electromagnetic waves at least in any one of a plurality of power transmission frequency channels within a power transmission frequency range.

[0016] In the above-described closed space sensor system, in the relationship between the transmission frequency and the receiving sensitivity of the antenna, the interval between the transmission frequency channels may be narrower than the interval between two transmission frequencies that provide the receiving sensitivity of the sensitivity threshold at which each of the multiple sensors can be driven.

[0017] In the above-described closed space sensor system, the electromagnetic wave irradiating device may set a combination of a plurality of power transmission frequency channels that can drive a predetermined number of sensors among the plurality of sensors.

[0018] In the above-mentioned closed space sensor system, the power transmitting unit of the electromagnetic wave irradiating device may be configured to irradiate the electromagnetic waves from a plurality of positions within the closed space.

[0019] In the closed space sensor system described above, the electromagnetic waves may be microwaves.

[0020] According to an aspect of the present invention, there is provided an operation method for a closed space sensor system, the operation method including irradiating electromagnetic waves from a power transmission unit of an electromagnetic wave irradiation device and converting the electromagnetic waves received via antennas into electricity to operate a plurality of sensors, each of the plurality of sensors having a power storage unit, and when the amount of stored electricity in the power storage unit reaches a common operation start threshold value for the plurality of sensors, each of the plurality of sensors starts operation, and the power transmission unit of the electromagnetic wave irradiation device and the plurality of sensors are disposed within the closed space.

[0021] In the above-described method of operating the closed space sensor system, the receiving sensitivity of at least some of the multiple sensors may differ within the closed space.

[0022] In the above-described method for operating the closed space sensor system, the peak of reception sensitivity of at least some of the multiple sensors may be outside the transmission frequency range of the electromagnetic waves that can be irradiated by the power transmission section of the electromagnetic wave irradiation device.

[0023] In the above-described method of operating the closed space sensor system, when the amount of power stored in the power storage unit reaches a drive start threshold common to the multiple sensors, each of the multiple sensors may start driving and wirelessly transmit a sensing signal.

[0024] In the above-described method for operating a closed space sensor system, the measurement cycles of the multiple sensors may be the same.

[0025] In the above-described method of operating the closed space sensor system, each of the multiple sensors may transmit a sensing signal via an antenna in a transmission period, generate a random number, and assign the random number to the transmission period.

[0026] In the above-described method of operating the closed space sensor system, each of the multiple sensors may transmit a sensing signal via an antenna on at least one of multiple signal transmission frequency channels.

[0027] In the above-described method for operating a closed space sensor system, an electromagnetic wave may be irradiated from a power transmitting unit of an electromagnetic wave irradiating device at least one of a plurality of power transmission frequency channels within a power transmission frequency range.

[0028] In the above-mentioned method of operating the closed space sensor system, in the relationship between the transmission frequency and the receiving sensitivity of the antenna, the spacing between the transmission frequency channels may be narrower than the spacing between two transmission frequencies that provide the receiving sensitivity of the sensitivity threshold at which each of the multiple sensors can be driven.

[0029] In the above-described method for operating the closed space sensor system, the electromagnetic wave irradiation device may set a combination of a plurality of power transmission frequency channels that can drive a predetermined number of sensors among the plurality of sensors.

[0030] In the above-mentioned method for operating the closed space sensor system, the power transmitting unit of the electromagnetic wave irradiating device may be configured to irradiate the electromagnetic waves from a plurality of positions within the closed space.

[0031] In the above-described method for operating a closed space sensor system, the electromagnetic waves may be microwaves. Effect of the Invention

[0032] According to the present invention, it is possible to provide a closed-space sensor system capable of stable operation within a closed space and a method for operating the closed-space sensor system. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a schematic diagram showing a closed space sensor system according to the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing the sensor according to the first embodiment. [Diagram 3] FIG. 3 is a graph showing an example of the relationship between the transmission frequency channels of the electromagnetic waves and the drivable sensors according to the first embodiment. [Figure 4]FIG. 4 is a graph showing an example of the relationship between the transmission frequency channels of the electromagnetic waves and the drivable sensors according to the first embodiment. [Diagram 5] FIG. 5 is a table showing an example of the relationship between the transmission frequency channels of the electromagnetic waves and the drivable sensors according to the first embodiment. [Figure 6] FIG. 6 is a graph showing a schematic relationship between the transmission frequency of the electromagnetic wave and the receiving sensitivity of the antenna of the sensor according to the first embodiment. [Figure 7] FIG. 7 is a graph showing a schematic relationship between the transmission frequency of the electromagnetic wave and the receiving sensitivity of the antenna of the sensor according to the first embodiment. [Figure 8] FIG. 8 is a graph showing a schematic relationship between the transmission frequency of the electromagnetic wave and the receiving sensitivity of the antenna of the sensor according to the first embodiment. [Figure 9] FIG. 9 is a graph showing a schematic relationship between the transmission frequency of the electromagnetic wave and the receiving sensitivity of the antenna of the sensor according to the first embodiment. [Figure 10] FIG. 10 is a graph showing a schematic relationship between the transmission frequency of the electromagnetic wave and the receiving sensitivity of the antenna of the sensor according to the first embodiment. [Figure 11] FIG. 11 is a graph showing a schematic relationship between the transmission frequency of the electromagnetic wave and the receiving sensitivity of the antenna of the sensor according to the first embodiment. [Figure 12] FIG. 12 is a schematic diagram showing the sensor according to the first embodiment. [Figure 13] FIG. 13 is a schematic graph showing the relationship between time and the amount of stored electricity in the sensor according to the first embodiment. [Figure 14] FIG. 14 is a schematic graph showing the relationship between time and the amount of stored electricity in the sensor according to the first embodiment. [Figure 15] FIG. 15 is a schematic diagram showing a sensor according to the second embodiment. [Figure 16] FIG. 16 is a schematic graph showing a transmission cycle of a sensing signal according to the second embodiment. [Figure 17] FIG. 17 is a schematic diagram showing a sensor system according to the fourth embodiment. [Figure 18] FIG. 18 is a schematic diagram showing a sensor system according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions, etc. should be judged in light of the following description. In addition, it goes without saying that the drawings include parts with different dimensional relationships and ratios.

[0035] (First embodiment) 1, the closed space sensor system according to the first embodiment includes a power transmission unit 40 of an electromagnetic wave irradiation device 140 that irradiates electromagnetic waves, and multiple sensors 30A, 30B, 30C, etc., each of which has an antenna and converts the electromagnetic waves received via the antenna into electric power to operate. In the closed space sensor system according to the first embodiment, each of the multiple sensors 30A, 30B, 30C, etc. includes a power storage unit, and when the amount of power stored in the power storage unit reaches a common operation start threshold value for the multiple sensors 30A, 30B, 30C, etc., each of the multiple sensors 30A, 30B, 30C, etc. starts operating.

[0036] The power transmission unit 40 of the electromagnetic wave irradiation device 140 includes, for example, an antenna. The power transmission unit 40 of the electromagnetic wave irradiation device 140 may irradiate electromagnetic waves at least one of a plurality of power transmission frequency channels within a power transmission frequency range. In the relationship between the power transmission frequency and the reception sensitivity of the antenna, the interval between the power transmission frequency channels may be narrower than the interval between two power transmission frequencies that provide reception sensitivity of a sensitivity threshold that allows each of the plurality of sensors 30A, 30B, 30C, etc. to be driven.

[0037] The multiple sensors 30A, 30B, 30C... and the power transmission unit 40 of the electromagnetic wave irradiation device 140 are arranged, for example, in the closed space 10. The parts of the electromagnetic wave irradiation device 140 other than the power transmission unit 40 may be arranged outside the closed space 10. The closed space 10 is, for example, a freeze-drying oven. For example, when the door of the freeze-drying oven is closed, the internal gas is aseptically shielded from the outside air. In the closed space 10, for example, multiple vials 20A, 20B, 20C... each storing a medicine to be freeze-dried are arranged on a shelf. The multiple sensors 30A, 30B, 30C... are arranged, for example, in at least a part of the multiple vials 20A, 20B, 20C... It is arbitrary which vial among the multiple vials 20A, 20B, 20C... the sensor is arranged in.

[0038] The number of the sensors 30A, 30B, 30C, etc. is arbitrary. Each of the sensors 30A, 30B, 30C, etc. is, for example, a temperature sensor. Each of the sensors 30A, 30B, 30C, etc. is wirelessly powered by electromagnetic waves such as microwaves irradiated from the power transmission unit 40 of the electromagnetic wave irradiating device 140, measures the temperature inside the vial during freeze-drying, and wirelessly emits a sensing signal including the measurement result.

[0039] For example, as shown in FIG. 2, the sensor 30A includes a power receiving unit 110 that receives power via electromagnetic waves, a measuring unit 160 that measures, for example, the temperature of an object to be measured, and a transmitting unit 150 that can transmit a sensing signal including a measurement result by the measuring unit 160. The power receiving unit 110 receives electromagnetic waves transmitted by the power transmitting unit 40 of the electromagnetic wave irradiating device 140 via a power receiving antenna 111. The sensor 30A also includes a power storage unit 120 that stores the power received by the power receiving unit 110. The power storage unit 120 is electrically connected to the power receiving unit 110, the measuring unit 160, and the transmitting unit 150. The measuring unit 160 and the transmitting unit 150 are driven by the power stored in the power storage unit 120. The transmitting unit 150 wirelessly transmits a sensing signal including the measurement result via a transmitting antenna 112.

[0040] The receiving antenna 111 and the transmitting antenna 112 may be separate or may be the same. The receiving antenna 111 is preferably capable of receiving electromagnetic waves in a wide frequency band. The transmitting antenna 112 is preferably capable of transmitting sensing signals in a wide frequency band. The sensor 30A may include a plurality of receiving antennas 111. The sensor 30A may also include a plurality of transmitting antennas 112. The other sensors 30B, 30C, etc. shown in FIG. 1 may also have the same configuration as the sensor 30A shown in FIG. 2.

[0041] A sensing signal receiving device 50 that receives sensing signals emitted by each of the multiple sensors 30A, 30B, 30C, etc. may be disposed in the closed space 10 shown in FIG. 1. The sensing signal receiving device 50 includes a receiving antenna that receives a sensing signal. It is preferable that the receiving antenna of the sensing signal receiving device 50 is capable of receiving sensing signals in a wide frequency band. The sensing signal receiving device 50 may include multiple receiving antennas. A plurality of sensing signal receiving devices 50 may be disposed in the closed space 10. The sensing signal receiving device 50 may further include a storage device that stores the received sensing signal. Each of the multiple sensors 30A, 30B, 30C, etc. may omit verification of establishment of a wireless connection with the sensing signal receiving device 50.

[0042] When the power transmission unit 40 of the electromagnetic wave irradiation device 140 irradiates electromagnetic waves, the electromagnetic waves may be reflected in the closed space 10, generating standing waves. Therefore, a null point where the transmitted power is weak may occur near the node of the standing wave. If the position of the null point coincides with the position of any one of the multiple sensors 30A, 30B, 30C, etc., power may not be supplied to the sensor, and the sensor may not operate. In addition, for example, if the closed space 10 is a freeze-drying furnace, when the ice in the furnace decreases due to sublimation, the propagation path of the electromagnetic waves in the furnace may change, and the position of the null point may change.

[0043] In response to this, the electromagnetic wave irradiation device 140 can set a combination of electromagnetic wave transmission frequency channels that a predetermined number of sensors among the multiple sensors 30A, 30B, 30C, etc. will be driven. Before the multiple sensors 30A, 30B, 30C, etc. detect the detection target, the electromagnetic wave irradiation device 140 changes the electromagnetic wave transmission frequency channel within a settable range and checks whether each of the multiple sensors 30A, 30B, 30C, etc. is driven for each electromagnetic wave transmission frequency channel. Changing the electromagnetic wave transmission frequency channel within a settable range is sometimes referred to as sweeping the electromagnetic wave transmission frequency.

[0044] The electromagnetic wave irradiation device 140 extracts a plurality of electromagnetic wave transmission frequency channels capable of driving at least one sensor. The electromagnetic wave irradiation device 140 removes from the options any electromagnetic wave transmission frequency channel that cannot drive any sensor. Furthermore, the electromagnetic wave irradiation device 140 creates a plurality of combinations of the electromagnetic wave transmission frequency channels and the drivable sensors. Furthermore, the electromagnetic wave irradiation device 140 sets a combination of the electromagnetic wave transmission frequency channels that drive a predetermined number of sensors among the plurality of sensors 30A, 30B, 30C, etc., based on the combination of the electromagnetic wave transmission frequency channels and the drivable sensors. The predetermined number can be set arbitrarily according to the detection target of the sensor and the required detection accuracy. The predetermined number may be the total number of the plurality of sensors 30A, 30B, 30C, etc.

[0045] The electromagnetic wave irradiation device 140 creates a sequence for sequentially irradiating electromagnetic waves of a combination of transmission frequency channels within a certain time. The certain time is, for example, the shortest measurement period among the measurement periods of the multiple sensors 30A, 30B, 30C, etc. If the measurement periods of the multiple sensors 30A, 30B, 30C, etc. are the same, the measurement period of each of the multiple sensors 30A, 30B, 30C, etc. will be the shortest measurement period. The measurement period can be set arbitrarily depending on the detection target of the sensor and the required detection accuracy.

[0046] 3, the electromagnetic wave irradiation device 140 confirms that two sensors 30A and 30B are driven at the power transmission frequency channel f1, and confirms that one sensor 30C is driven at the power transmission frequency channel f2. In this case, the electromagnetic wave irradiation device 140 creates a sequence for sequentially irradiating the electromagnetic waves of the power transmission frequency channel f1 and the electromagnetic waves of the power transmission frequency channel f2 within the shortest measurement period among the respective measurement periods of the sensors 30A, 30B, and 30C.

[0047] 4, the electromagnetic wave irradiation device 140 sweeps the power transmission frequency channels f1 to f10, and confirms that the sensor 30A is driven at the power transmission frequency channels f3 and f4, and the sensor 30B is driven at the power transmission frequency channels f8 and f9. When it is sufficient to drive two sensors 30A and 30B, the electromagnetic wave irradiation device 140 creates a sequence for sequentially irradiating the electromagnetic waves of the power transmission frequency channels f3, f4, f8, and f9 within the shortest measurement period among the respective measurement periods of the sensors 30A and 30B.

[0048] The electromagnetic wave irradiation device 140 shown in FIG. 1 repeats irradiating electromagnetic waves using a combination of the set electromagnetic wave transmission frequency channels in a certain time according to the created sequence. Each of the predetermined number of sensors 30A, 30B, 30C, etc. receives electromagnetic waves of the drivable transmission frequency channels at least once within a measurement period. Therefore, each of the predetermined number of sensors 30A, 30B, 30C, etc. can be driven at least once within a measurement period to detect the detection target. The electromagnetic wave irradiation device 140 may simultaneously irradiate all or at least a part of the electromagnetic waves of the set transmission frequency channel combinations.

[0049] The electromagnetic wave irradiation device 140 may reconfigure the combination of electromagnetic wave transmission frequency channels driven by a predetermined number of the multiple sensors 30A, 30B, 30C, etc. while the multiple sensors 30A, 30B, 30C, etc. are detecting the detection target.

[0050] For example, if the currently set combination of electromagnetic wave transmission frequency channels becomes unable to drive any of the multiple sensors 30A, 30B, 30C, etc., the electromagnetic wave irradiation device 140 adds the electromagnetic wave transmission frequency channel capable of driving the sensor that is no longer able to be driven to the currently set combination of electromagnetic wave transmission frequency channels.

[0051] Furthermore, if the added electromagnetic wave transmission frequency channel can drive a predetermined number of sensors among the multiple sensors 30A, 30B, 30C, etc. even if at least one transmission frequency channel from the currently set combination of electromagnetic wave transmission frequency channels is deleted, the electromagnetic wave irradiation device 140 deletes the transmission frequency channel that can be deleted, and resets the combination of the remaining transmission frequency channel combination that has not been deleted and the added transmission frequency channel as the combination of electromagnetic wave transmission frequency channels.

[0052] 5(a), the combination of power transmission frequency channels f1, f3, and f10 that was initially capable of driving all of the multiple sensors 30A, 30B, 30C, 30D, and 30E is no longer capable of driving the sensor 30E. In this case, if the irradiation of all electromagnetic waves of the power transmission frequency channels f1, f3, and f10 is stopped, the transmission frequency channels of the electromagnetic waves are changed within a settable range, and the combination of the transmission frequency channels of the electromagnetic waves is reset, the driving of all of the multiple sensors is temporarily stopped.

[0053] 5(b), the electromagnetic wave irradiation device 140 adds, for example, electromagnetic wave irradiation of transmission frequency channels f2 and f4 without stopping irradiation of electromagnetic waves with the combinations of power transmission frequency channels f1, f3, and f10 that were previously capable of driving all of the multiple sensors 30A, 30B, 30C, 30D, and 30E. The electromagnetic wave irradiation device 140 confirms that the electromagnetic wave transmission frequency channel f2 is capable of driving the sensor 30E, and that the electromagnetic wave transmission frequency channel f4 is not capable of driving the sensor 30E.

[0054] Furthermore, as shown in FIG. 5(c), when the electromagnetic waves of the added power transmission frequency channel f2 can drive not only the sensor 30E but also the sensor 30D, even if the power transmission frequency channel f10 capable of driving the sensor 30D is deleted from the combination of the previously set power transmission frequency channels, all of the multiple sensors 30A, 30B, 30C, 30D, and 30E can be driven. In this case, the electromagnetic wave irradiation device 140 deletes the deletable power transmission frequency channel f10. The electromagnetic wave irradiation device 140 resets the combination of the remaining power transmission frequency channel combination f1, f3 and the added power transmission frequency channel f2 as the combination of the power transmission frequency channels.

[0055] The timing for resetting the combination of the electromagnetic wave frequencies is arbitrary. For example, the resetting may be performed constantly, or may be performed periodically based on a timer included in the electromagnetic wave irradiation device 140 or a timer connected to the electromagnetic wave irradiation device 140. Alternatively, the electromagnetic wave irradiation device 140 may reset the combination of the electromagnetic wave frequencies when it confirms that at least a part of the multiple sensors 30A, 30B, 30C, etc. is not operating. When the electromagnetic wave irradiation device 140 confirms that at least a part of the multiple sensors 30A, 30B, 30C, etc. is not operating, the electromagnetic wave irradiation device 140 may immediately reset the combination of the electromagnetic wave frequencies, or may reset the combination of the electromagnetic wave frequencies after a predetermined time has elapsed. Alternatively, the electromagnetic wave irradiation device 140 may receive a trigger signal for resetting the combination of the electromagnetic wave frequencies and reset the combination of the electromagnetic wave frequencies.

[0056] In addition, the state of reception of electromagnetic waves by each antenna of the multiple sensors 30A, 30B, 30C, etc. may change due to, for example, a change in the position of the power transmission unit 40 of the electromagnetic wave irradiation device 140, a change in the arrangement of the multiple sensors 30A, 30B, 30C, etc., and a change in the presence or absence of objects between the power transmission unit 40 of the electromagnetic wave irradiation device 140 and the multiple sensors 30A, 30B, 30C, etc.

[0057] For example, if there is a conductive material such as metal in the vicinity, the reception state of the electromagnetic wave by the antenna of the sensor may change. As shown in Fig. 6, the frequency that gives the peak of the reception sensitivity of the antenna of the sensor may be called the resonance frequency. For example, when the antenna of the sensor is placed away from the conductive material, even if the transmission frequency that gives the peak of the reception sensitivity of the antenna of the sensor is within the transmission frequency range that the power transmission unit 40 of the electromagnetic wave irradiation device 140 can irradiate, when the antenna of the sensor is placed in the vicinity of the conductive material, the frequency that gives the peak of the reception sensitivity of the antenna of the sensor may shift outside the transmission frequency range that the power transmission unit 40 of the electromagnetic wave irradiation device 140 can irradiate, as shown in Figs. 7 and 8.

[0058] For this reason, for example, when the wall forming the closed space is made of a conductive material such as metal, the reception sensitivity of the antenna of a sensor near the wall may differ from the reception sensitivity of the antenna of a sensor away from the wall. Thus, the reception sensitivity of at least some of the multiple sensors 30A, 30B, 30C, etc. may differ within the closed space.

[0059] Each of the multiple sensors 30A, 30B, 30C... can be driven by the received power when the receiving sensitivity of the antenna is equal to or higher than a predetermined sensitivity threshold. As shown in Fig. 9, in the relationship of the receiving sensitivity of the antenna to the power transmission frequency, if the antenna of the sensor receives electromagnetic waves of a power transmission frequency between two frequencies that give the receiving sensitivity of the sensitivity threshold at which the sensor can be driven, the sensor can be driven. In the closed space sensor system according to the first embodiment, in the relationship of the receiving sensitivity of the antenna to the power transmission frequency, the interval W between two frequencies that give the receiving sensitivity of the sensitivity threshold at which the multiple sensors 30A, 30B, 30C... can be driven is set to 0.015 Hz. H The electromagnetic wave irradiation device 140 can set the transmission frequency channel f 1 , f 2 , f 3 , f 4 Interval W c is narrow.

[0060] Therefore, as shown in FIG. 10, even if the frequency at which the antenna's receiving sensitivity peaks shifts outside the range of power transmission frequencies that the power transmission unit 40 of the electromagnetic wave irradiation device 140 can irradiate, the power transmission frequency channel f corresponding to a receiving sensitivity equal to or higher than the sensitivity threshold at which the sensor can be driven is n But the interval W H Therefore, even if the frequency that gives the peak of the receiving sensitivity of the antenna shifts to outside the range of power transmission frequencies that the power transmission unit 40 of the electromagnetic wave irradiation device 140 can irradiate, the sensor can remain within the interval W H It can be driven by electromagnetic waves of the transmission frequency channel remaining between the interval W H Any number of transmission frequency channels may remain between .

[0061] As shown in FIG. 11, suppose that the interval W between two transmission frequencies that provides the reception sensitivity threshold at which the sensor can be driven is H is the transmission frequency channel f 1 , f 2 , f 3 , f 4 Interval W c If the range is narrower, when the peak of the antenna's receiving sensitivity for the transmission frequency shifts outside the range of transmission frequencies that the electromagnetic wave irradiation device can irradiate, there is a high possibility that there will be no transmission frequency channel corresponding to a receiving sensitivity above the sensitivity threshold at which the sensor can be operated.

[0062] In contrast, as described above, in the closed space sensor system according to the first embodiment, as shown in FIG. 9, in the relationship between the power transmission frequency and the reception sensitivity of the antenna, the interval W between two power transmission frequencies that provides the reception sensitivity of the sensitivity threshold at which the sensor can be driven is H than the transmission frequency channel f 1 , f 2 , f 3 , f 4 Interval W cSince the frequency band is narrow, even if it becomes impossible to drive a sensor with a certain power transmission frequency channel, it is easy to drive the sensor with a different power transmission frequency channel. Therefore, in the closed space sensor system according to the first embodiment, even if the frequency at which the antenna's reception sensitivity peak is reached in at least some of the sensors 30A, 30B, 30C, etc., falls outside the transmission frequency range of the electromagnetic waves that the power transmission unit 40 of the electromagnetic wave irradiation device 140 can irradiate, it is easy to continue measurement. Therefore, the tolerance range for the shift in the frequency at which the antenna's reception sensitivity peak is reached due to the environment around the sensor is widened.

[0063] Each of the sensors 30A, 30B, 30C, etc. shown in FIG. 1 may further include a comparison unit 130 that compares the amount of stored power in the power storage unit 120 shown in FIG. 12 with a drive start threshold. The drive start threshold is common to the sensors 30A, 30B, 30C, etc. shown in FIG. 1. When the sensors 30A, 30B, 30C, etc. start measurement, the power transmission unit 40 of the electromagnetic wave irradiation device 140 starts irradiating electromagnetic waves, and the power storage units 120 of the sensors 30A, 30B, 30C, etc. start charging. In each of the sensors 30A, 30B, 30C, etc., when the comparison unit 130 determines that the amount of stored power in the power storage unit 120 is equal to or greater than the drive start threshold, the measurement unit 160 starts measuring the object to be measured, and the transmission unit 150 transmits a sensing signal including the measurement result by the measurement unit 160 every time the measurement unit 160 measures the object to be measured.

[0064] As shown in Fig. 13, the sensor 30A does not start measurement until the amount of stored power in the power storage unit 120 becomes equal to or greater than the drive start threshold. When the amount of stored power in the power storage unit 120 becomes equal to or greater than the drive start threshold, the sensor 30A starts measurement at a predetermined measurement period. The same is true for the other sensors 30B, 30C, etc. Note that, although the example shown in Fig. 13 shows an example in which the power storage unit 120 does not charge to equal or exceed the drive start threshold, the power storage unit 120 may charge to equal or exceed the drive start threshold.

[0065] As described above, the receiving sensitivity of the antennas of the multiple sensors 30A, 30B, 30C, etc. may change depending on the surrounding environment. Therefore, the receiving sensitivity of the antennas of the multiple sensors 30A, 30B, 30C, etc. may differ from one another. Therefore, the time until the amount of stored power in the power storage unit of the multiple sensors 30A, 30B, 30C, etc. becomes equal to or greater than the drive start threshold may also differ from one another among the multiple sensors 30A, 30B, 30C, etc.

[0066] 14, the amount of charge stored in the power storage unit of sensor 30B becomes equal to or greater than the drive start threshold before sensor 30A, and sensor 30B starts measuring the object to be measured at a predetermined measurement period. After that, the amount of charge stored in the power storage unit of sensor 30A also becomes equal to or greater than the drive start threshold, and sensor 30A starts measuring the object to be measured at a predetermined measurement period.

[0067] When the measurement period of the sensor 30A and the measurement period of the sensor 30B are the same, the sensors 30A and 30B, which have different measurement start times, measure the measurement target at different timings and wirelessly emit sensing signals including the measurement results. Therefore, the timing at which the sensor 30A emits a sensing signal differs from the timing at which the sensor 30B emits a sensing signal. Possible Therefore, it may be possible to avoid interference between sensing signals and traffic congestion. The same is true when the number of sensors is three or more.

[0068] Second embodiment 1, the transmitting unit 150 shown in Fig. 15 may transmit a sensing signal including a measurement result by the measuring unit 160 at a predetermined transmission period. Each of the multiple sensors 30A, 30B, 30C, etc. may further include a random number assigning unit 170 that generates a random number and assigns the random number to the transmission period of the sensing signal.

[0069] When the transmission periods of the multiple sensors 30A, 30B, 30C, etc. are the same, the multiple sensors 30A, 30B, 30C, etc. may transmit sensing signals at the same timing, as shown in Fig. 16(a). In contrast, in each of the multiple sensors 30A, 30B, 30C, etc., the random number assigning unit 170 generates a positive or negative random number and assigns the generated random number to the transmission period, so that the multiple sensors 30A, 30B, 30C, etc. may transmit sensing signals at different timings, as shown in Fig. 16(b). This may make it possible to avoid interference between sensing signals and traffic congestion.

[0070] Third embodiment The transmitting unit of each of the multiple sensors 30A, 30B, 30C, etc. shown in FIG. 1 may change the signal transmission frequency channel of the sensing signal to check whether the sensing signal is received by the sensing signal receiving device 50. The transmitting unit of each of the multiple sensors 30A, 30B, 30C, etc. may transmit the sensing signal using the signal transmission frequency channel in which the establishment of the wireless connection has been confirmed. The transmitting unit of each of the multiple sensors 30A, 30B, 30C, etc. may transmit the sensing signal using the multiple signal transmission frequency channels in which the establishment of the wireless connection has been confirmed. The transmitting unit of each of the multiple sensors 30A, 30B, 30C, etc. may check the establishment of the wireless connection before the start of measurement or during measurement.

[0071] (Fourth embodiment) 17, in the sensor system according to the fourth embodiment, the power transmission unit 40 of the electromagnetic wave irradiation device 140 has multiple power transmission units 40A, 40B, and 40C that each irradiate electromagnetic waves, and the positions of the power transmission units 40A, 40B, and 40C may be different. The number of the multiple power transmission units 40A, 40B, and 40C is arbitrary.

[0072] The electromagnetic wave irradiation device 140 checks whether each of the multiple sensors 30A, 30B, 30C, etc. is activated for each of the power transmission units 40A, 40B, 40C. The electromagnetic wave irradiation device 140 creates multiple combinations of the positions of the power transmission units and the activatable sensors. Furthermore, the electromagnetic wave irradiation device 140 sets a combination of the positions of the power transmission units that activates a predetermined number of sensors among the multiple sensors 30A, 30B, 30C, etc., based on the combination of the positions of the power transmission units and the activatable sensors.

[0073] The electromagnetic wave irradiation device 140 creates a sequence for irradiating electromagnetic waves from the power transmission units at positions included in the set combination. Alternatively, the electromagnetic wave irradiation device 140 may irradiate electromagnetic waves simultaneously from all or at least some of the power transmission units at positions included in the set combination.

[0074] The null point is easily affected by the relationship of the positions and directions of the power transmitting units 40A, 40B, and 40C with the inner wall of the closed space 10 and other objects that reflect electromagnetic waves. In addition, the inner wall of the closed space 10 may not be movable. In response to this, it is possible to change the position of the null point that overlaps with the position of the sensor by changing the position of the power transmitting unit that irradiates the electromagnetic waves. This allows the sensor to be driven stably.

[0075] Fifth embodiment In the sensor system according to the fifth embodiment, as shown in Fig. 18, the power transmission unit 40 of the electromagnetic wave irradiation device 140 includes an antenna that changes the irradiation direction of the electromagnetic wave. The antenna is, for example, a directional antenna, and a phased array antenna, a movable parabolic antenna, or the like can be used. The phased array antenna can change the directivity without using a moving mechanism, so that dust generation can be suppressed.

[0076] The electromagnetic wave irradiation device 140 checks whether each of the multiple sensors 30A, 30B, 30C, etc. is activated for each electromagnetic wave irradiation direction. The electromagnetic wave irradiation device 140 creates multiple combinations of electromagnetic wave irradiation directions and drivable sensors. Furthermore, the electromagnetic wave irradiation device 140 sets a combination of electromagnetic wave irradiation directions that activates a predetermined number of sensors among the multiple sensors 30A, 30B, 30C, etc., based on the combination of the electromagnetic wave irradiation direction and the drivable sensors.

[0077] The electromagnetic wave irradiation device 140 creates a sequence for irradiating electromagnetic waves in the irradiation directions included in the set combination. By changing the irradiation direction of the electromagnetic waves, it is possible to change the position of the null point that overlaps with the position of the sensor. This makes it possible to drive the sensor stably.

[0078] (Other embodiments) Although the present invention has been described above by the embodiments, the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. Various alternative embodiments, examples, and operation techniques should become apparent to those skilled in the art from this disclosure. For example, the above-mentioned embodiments may be combined. In addition, in the above embodiment, a freeze-drying oven is used as the closed space, but the closed space may be a room, a factory, a storage, a chamber, a tank, a furnace, etc. The gas in the closed space may be kept clean. The closed space may be evacuated. The closed space may be a sterile pharmaceutical processing space. In addition, the sensor may measure humidity based on surface acoustic waves. The sensor may measure gas concentrations such as oxygen and carbon dioxide. Alternatively, the sensor may measure the presence or absence or movement of each item. The sensor may be placed in various containers other than vials, or may not be placed in a container. The sensor may be placed in items such as products, artworks, and exhibits. In this way, it should be understood that the present invention encompasses various embodiments and the like not described here. [Explanation of symbols]

[0079] REFERENCE SIGNS LIST 10 closed space, 20 vial, 30 sensor, 40 power transmission unit, 50 sensing signal receiving device, 110 power receiving unit, 111 power receiving antenna, 112 transmitting antenna, 120 power storage unit, 130 comparison unit, 140 electromagnetic wave irradiation device, 150 transmission unit, 160 measurement unit, 170 random number assignment unit

Claims

1. An electromagnetic wave irradiation device including a power transmission unit that irradiates electromagnetic waves; a plurality of sensors each including an antenna, the sensors converting the electromagnetic waves received via the antenna into electric power to operate the sensors; Equipped with Each of the plurality of sensors includes a power storage unit, and when an amount of power stored in the power storage unit reaches a drive start threshold common to the plurality of sensors, each of the plurality of sensors starts driving; The power transmission unit and the plurality of sensors of the electromagnetic wave irradiation device are disposed in a closed space. A closed space sensor system, comprising: The power transmission unit of the electromagnetic wave irradiation device irradiates electromagnetic waves at least in one of a plurality of power transmission frequency channels within a power transmission frequency range, In a relationship between the transmission frequency and the receiving sensitivity of the antenna, the interval between the transmission frequency channels is narrower than the interval between two transmission frequencies that provide the receiving sensitivity of a sensitivity threshold at which each of the plurality of sensors can be driven. Closed space sensor system.

2. The closed space sensor system according to claim 1 , wherein receiving sensitivities of at least some of the plurality of sensors vary within the closed space.

3. Each of the plurality of sensors is a transmitter that transmits a sensing signal via an antenna at a transmission period; a random number assigning unit that generates a random number and assigns the random number to the transmission period; The closed space sensor system of claim 1 , comprising:

4. The closed space sensor system according to claim 1 , wherein each of the plurality of sensors further comprises a transmitter that transmits a sensing signal via an antenna on at least one of a plurality of signal transmission frequency channels.

5. The enclosed space sensor system of claim 4 , further comprising a plurality of sensing signal receiving devices for receiving the sensing signals.

6. The enclosed space sensor system of claim 1 , wherein the receiver sensitivity peaks of at least some of the plurality of sensors can be outside the transmission frequency range.

7. The closed space sensor system according to claim 1 or 6, wherein the electromagnetic wave irradiation device sets a combination of a plurality of power transmission frequency channels that can drive a predetermined number of the sensors among the plurality of sensors.

8. The closed space sensor system according to claim 1 , wherein the power transmitting unit of the electromagnetic wave application device is configured to apply the electromagnetic waves from a plurality of positions within the closed space.

9. Irradiating electromagnetic waves from a power transmission unit of an electromagnetic wave irradiation device; converting the electromagnetic waves received via antennas into electric power to drive a plurality of sensors; Including, Each of the plurality of sensors includes a power storage unit, and when an amount of power stored in the power storage unit reaches a drive start threshold common to the plurality of sensors, each of the plurality of sensors starts driving; The power transmission unit of the electromagnetic wave irradiation device and the plurality of sensors are arranged in a closed space.

1. A method of operating a confined space sensor system, comprising: The power transmission unit of the electromagnetic wave irradiation device irradiates electromagnetic waves at least in one of a plurality of power transmission frequency channels within a power transmission frequency range, In a relationship between the transmission frequency and the receiving sensitivity of the antenna, the interval between the transmission frequency channels is narrower than the interval between two transmission frequencies that provide the receiving sensitivity of a sensitivity threshold at which each of the plurality of sensors can be driven. A method of operation of a confined space sensor system.

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