Vibration sensor and vibration frequency detection system

Abstract

To provide a vibration sensor that can be reduced in device size and thickness and a vibration frequency detection system.SOLUTION: Provided is a vibration sensor for detecting vibration frequency, comprising a dielectric layer, a gas layer, a metal layer, and an elastic member, with the gas layer located between the dielectric layer and the metal layer, the elastic member being provided to the gas layer, and the elastic member connected at one end to the dielectric layer and connected at the other end to the metal layer. The vibration sensor is constructed such that the elastic member extends or contracts and the distance between the dielectric layer and the metal layer varies, causing the reflection loss of a radio wave to vary. The reflection loss is based on first electric power of a first radio wave entering the dielectric layer and second electric power of a second radio wave reflected by the metal layer after entering the dielectric layer and then radiated from the dielectric layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration sensor and a vibration frequency detection system. [Background technology]

[0002] Patent Document 1 discloses a vibration sensor used to diagnose deterioration of structures such as buildings, etc. The vibration sensor described in Patent Document 1 includes an antenna provided on a housing, a wireless circuit board used to generate and output a signal related to vibrations detected by the vibration sensor, a battery for driving various circuits, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6197794 Summary of the Invention [Problem to be solved by the invention]

[0004] Vibration sensors that use a battery (power source) or the like require various components such as the battery, a circuit board, and an antenna, and therefore tend to be large in size.

[0005] An object of the present invention is to provide a vibration sensor and a vibration frequency detection system that can be made smaller and thinner. [Means for solving the problem]

[0006] According to the present invention, there is provided a vibration sensor for detecting vibration frequency, comprising a dielectric layer, a gas layer, a metal layer, and an elastic member, wherein the gas layer is arranged between the dielectric layer and the metal layer, the elastic member is provided in the gas layer, and the elastic member has one side connected to the dielectric layer and the other side connected to the metal layer, the vibration sensor is configured to change the reflection loss of radio waves as the elastic member expands and contracts to change the distance between the dielectric layer and the metal layer, and the reflection loss is based on a first power of a first radio wave incident on the dielectric layer and a second power of a second radio wave that is incident on the dielectric layer, reflected by the metal layer, and radiated from the dielectric layer.

[0007] According to the present invention, the elastic member expands and contracts, changing the distance between the weight member and the metal layer, thereby changing the reflection loss of radio waves. Since the reflection loss of radio waves is used to detect the frequency, there is no need for, for example, a wireless circuit board, a power circuit and a power source (battery) to drive it, etc., and the device can be made smaller and thinner. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of a vibration frequency detection system 100. As shown in FIG. [Figure 2] FIG. 2 is a perspective view of the vibration sensor 2 (vibration sensor main body 2B). [Figure 3] FIG. 3 is a diagram showing the vibration sensor 2 shown in FIG. 2 as seen from the side, and is an explanatory diagram of incident and reflected radio waves. [Figure 4] FIG. 4 is a functional block diagram of the information processing unit 1B. [Figure 5] FIG. 5 is a functional block diagram of the control unit 12. [Figure 6] FIG. 6 is a graph showing how the return loss changes as the distance x between the weight member 2a and the metal layer 2c changes due to vibration of the vibration sensor 2. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently.

[0010] 1. Description of the configuration of the embodiment As shown in FIG. 1, in the embodiment, the vibration frequency detection system 100 includes a transmitting / receiving device 1 and a vibration sensor 2 capable of communicating with the transmitting / receiving device 1. In the vibration frequency detection system 100, the vibration sensor 2 has a radio wave absorber structure and an elastic structure (a spring structure in the embodiment). This changes the absorption frequency band of the vibration sensor 2 as a radio wave absorber. The detailed configuration of the vibration sensor 2 according to the embodiment will be described in detail later. As shown in FIG. 2, the vibration sensor 2 includes a weight member 2a, an elastic member 2b, a metal layer 2c, and a gas layer 2d. When the weight member 2a vibrates (when the distance x between the weight member 2a and the metal layer 2c changes), the radio wave absorption characteristics change. In the vibration frequency detection system 100, the power of the transmitted radio wave and the power of the radio wave reflected by the vibration sensor 2 are obtained, thereby making it possible to detect the frequency of the vibration sensor 2.

[0011] 1-1.Transmitter / Receiver 1 As shown in FIGS. 1 and 4, the transmitting / receiving device 1 includes a housing 1A, an information processing unit 1B, and an antenna unit 1C.

[0012] 1-1-1. Housing 1A The housing 1A is a case that houses the information processing unit 1B. The housing 1A also has an antenna unit 1C.

[0013] 1-1-2. Information Processing Section 1B The information processing unit 1B has functions such as generating and processing transmission signals and receiving and processing reception signals. Here, the transmission signal is a signal that is emitted as a radio wave (first radio wave) via the antenna unit 1C, and the radio wave propagates through space to reach the vibration sensor 2. The reception signal is a signal that is a radio wave (second radio wave) reflected by the vibration sensor 2, propagates through space, is received by the antenna unit 1C, and is processed in the information processing unit 1B.

[0014] 4, the information processing unit 1B includes a communication unit 10, a storage unit 11, a control unit 12, an output unit 13, and an input unit 14. Also, as shown in FIG. 5, the control unit 12 includes a transmission unit 120, a reception unit 121, a vibration frequency acquisition unit 122, and a notification unit 123.

[0015] Each component of the information processing unit 1B may be implemented by software or hardware. When implemented by software, various functions can be realized by a CPU executing a computer program. The program may be stored on a non-transitory computer-readable recording medium, provided as a downloadable file from an external server, or implemented by cloud computing, which reads a program stored in an external storage unit and realizes the functions. When implemented by hardware, various circuits such as an ASIC, FPGA, or DRP can be used. In the embodiments, various information and concepts encompassing such information are handled. These are represented by high and low signal values ​​or quantum bits as a collection of binary bits consisting of 0 or 1, and communication and calculations can be performed by the above software or hardware aspects. The software may be a general-purpose OS or a dedicated OS.

[0016] The communication unit 10 can employ wired communication means such as USB, IEEE1394, Thunderbolt (registered trademark), wired LAN network communication, etc. The communication unit 10 may be configured to be connected to a communication network via wireless communication means such as wireless LAN network communication, mobile communication such as 3G / LTE / 5G, Bluetooth (registered trademark) communication, etc. The communication unit 10 may also be configured to use both the wired communication means and wireless communication means described above.

[0017] The storage unit 11 stores, for example, various programs, constants, variables, and setting values ​​of the information processing unit 1B executed by the control unit 12. The storage unit 11 also stores, for example, information to be processed by each functional unit of the information processing unit 1B. The storage unit 11 may be a storage device such as a solid state drive (SSD), or a random access memory (RAM) that stores temporarily required information (arguments, arrays, etc.) related to program calculations. The information processing unit 1B may also use an external storage unit (for example, an external storage medium, a cloud, etc.) in addition to the storage unit 11.

[0018] The control unit 12 is configured to execute processing and control related to the information processing of the information processing unit 1B. The control unit 12 can be configured, for example, by a central processing unit (CPU), and in the embodiment, the control unit 12 is an example of a processor capable of executing various programs. The control unit 12 realizes various functions related to the information processing unit 1B, for example, by reading out programs stored in the storage unit 11. Furthermore, the information processing of the software in the information processing unit 1B is realized, for example, by the control unit 12 as hardware processing the various programs stored in the storage unit 11.

[0019] The output unit 13 is, for example, a display unit of the information processing unit 1B. The output unit 13 may be, for example, included in the housing 1A or may be externally attached. The output unit 13 displays a graphical user interface (GUI) screen that can be operated by the user. The output unit 13 may be, for example, a display device such as a CRT display, a liquid crystal display, an organic EL display, a plasma display, or an electronic paper display, as well as a display device such as an illuminable light or a projector. It is optional whether or not the information processing unit 1B includes the output unit 13. For example, the output of the information processing unit 1B may be displayed on a display unit located at a location separate from the location where the information processing unit 1B is installed. The output unit 13 may also have a device that outputs audio.

[0020] The input unit 14 is configured to receive, for example, an operation input made by a user. The input unit 14 may be included in the housing 1A or may be externally attached. For example, a touch panel, a switch button, a mouse, a keyboard, etc. may be used as the input unit 14. It is optional whether or not the information processing unit 1B includes the input unit 14. For example, the information processing unit 1B may receive an operation input to the information processing unit 1B via the communication unit 10 from an information processing terminal located at a location separate and apart from the location where the information processing unit 1B is installed.

[0021] 1-1-2-1. Transmitter 120 The transmitting unit 120 is configured to be able to transmit a first radio wave to the vibration sensor 2. That is, the transmitting unit 120 is configured to perform processing for generating the first radio wave, thereby radiating the first radio wave via the antenna unit 1C. The signal generated by the transmitting unit 120 is, for example, a signal output from an oscillator (not shown) amplified by an amplifier, and radiated from the antenna unit 1C as a carrier wave of desired power.

[0022] The frequency (GHz) of the signal generated by the transmitter 120 (the first radio wave transmitted by the transmitter 120) specifically includes, for example, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, and 1500, and may also be within a range between any two of the numerical values ​​exemplified here. For example, the first radio wave transmitted by the transmitter 120 is 15 GHz or higher. Note that the higher the frequency, the more the resolution of the vibration frequency detection system 100 can be improved, and the more compact and thinner the vibration sensor 2 can be made. The frequency may be divided into multiple frequency ranges, such as frequencies above 100 GHz and below 400 GHz, and frequencies above 800 GHz and below 1000 GHz, as specified by the numerical values ​​listed above.

[0023] The information processing unit 1B is housed in the housing 1A. That is, the transmitting unit 120, the receiving unit 121, and the frequency acquiring unit 122 are provided in the housing 1A independent of the vibration sensor 2 (housing 2A). In the embodiment, the case where the transmitting unit 120 and the receiving unit 121 are housed in the same housing 1A has been described as an example, but the present invention is not limited to this. The transmitting unit 120 and the receiving unit 121 may be housed in separate housings. In this case, the information processing unit 1B is disposed separately in each of the two housings. The receiving unit 121 is preferably housed in the same housing as the vibration frequency acquiring unit 122 and the notifying unit 123. It is also preferable that the information processing unit in the housing housing the transmitting unit 120 is configured to be able to communicate with the information processing unit in the housing housing the receiving unit 121.

[0024] 1-1-2-2. Receiving unit 121 The receiving unit 121 is configured to be able to receive a second radio wave w2 from the vibration sensor 2. The receiving unit 121 receives the second radio wave w2 via the antenna unit 1C. The second radio wave is a reflected wave of the first radio wave w1 transmitted to the vibration sensor 2. Because the vibration sensor 2 functions as a radio wave absorber, the second radio wave w2 is attenuated compared to the first radio wave w1. In other words, the second power P2, which is the power corresponding to the second radio wave w2, is smaller than the first power P1, which is the power corresponding to the first radio wave w1.

[0025] 1-1-2-3.Frequency acquisition section 122 The frequency acquisition unit 122 acquires the frequency using a reflection loss based on the first power of the first radio wave and the second power of the second radio wave. Here, the reflection loss is based on the first power of the first radio wave incident on the vibration sensor 2 (weight member 2a described later) and the second power of the second radio wave that is incident on the vibration sensor 2 (weight member 2a) and then reflected by a metal layer 2c of the vibration sensor 2 described later and radiated from the weight member 2a.

[0026] The frequency acquisition unit 122 has a function of acquiring power. For example, if the power of the signal (first radio wave w1 radiated from the antenna unit 1C) transmitted from the transmission unit 120 is predetermined, the frequency acquisition unit 122 can acquire this value from the storage unit 11. Furthermore, the frequency acquisition unit 122 can acquire the power of the signal (second radio wave w2 received by the antenna unit 1C) received by the reception unit 121 by using, for example, a power detection circuit (not shown) provided in the information processing unit 1B.

[0027] When the weight member 2a of the vibration sensor 2 vibrates, in other words, when the distance x between the weight member 2a and the metal layer 2c changes, the radio wave absorption characteristics change, as shown in Fig. 6. Fig. 6 shows the radio wave absorption characteristics when the distance x is 7 mm, 7.5 mm, and 8 mm, respectively, and it can be seen that each absorption characteristic is unique depending on the distance x. Fig. 6 shows only 7 mm, 7.5 mm, and 8 mm as examples, but it is recommended to prepare multiple graphs (absorption characteristics) depending on the expected length and accuracy of the distance x. The radio wave absorption characteristics are specific to the configuration of the vibration sensor 2 (vibration sensor main body 2B) and are predetermined. The storage unit 11 stores information relating to the relationship (relationship between reflection loss and frequency) shown in the graph of Fig. 6. This information may be a table or may be a formula that is calculated sequentially by the frequency acquisition unit 122.

[0028] In this embodiment, the reflection loss (dB) is used as the radio wave absorption characteristic. The reflection loss can be defined as, for example, -10Log(P2 / P1), where P1 corresponds to the first power, which is the power of the first radio wave w1, and P2 corresponds to the second power, which is the power of the second radio wave.

[0029] The frequency acquisition unit 122 can sequentially calculate the return loss at a predetermined timing based on the values ​​of P1 and P2. Then, as shown in FIG. 6, the distance x between the weight member 2a and the metal layer 2c can be determined based on the acquired return loss. By acquiring multiple return losses, the vibration state of the weight member 2a (variation in the distance x over time) can be determined, and as a result, the vibration (frequency) of the vibration sensor 2 can be detected. In this way, the frequency acquisition unit 122 acquires the vibration (frequency) of the vibration sensor 2 based on the first power P1 of the first radio wave w1 and the second power P2 of the second radio wave w2.

[0030] In the embodiment, the frequency acquisition unit 122 has been described as having a function of calculating return loss, but this is not limited to this. The calculation may be performed in an external device other than the transceiver 1, and the frequency acquisition unit 122 may acquire the calculation result via the communication unit 10.

[0031] 1-1-2-4. Notification unit 123 The notification unit 123 has a function of notifying the user of information related to the vibration of the vibration sensor 2 acquired by the vibration frequency acquisition unit 122. If the vibration sensor 2 is, for example, a vibration meter, the notification unit 123 controls the output unit 13 to notify the user of the current vibration frequency of the vibration sensor 2. If the vibration sensor 2 is, for example, a seismometer, the notification unit 123 can control the output unit 13 to notify the user of the current seismic intensity, and if the vibration sensor 2 is, for example, a sensor used to determine the deterioration of a structure, the notification unit 123 can control the output unit 13 to notify the user of the deterioration state of the structure. Note that the uses of the vibration sensor 2 are not limited to these, and the vibration sensor 2 can also be used for other purposes. It is optional whether or not the vibration frequency detection system 100 includes the notification unit 123.

[0032] 1-2. Vibration sensor 2 The vibration sensor 2 shown in Figs. 1 to 3 is configured so that the reflection loss of radio waves is changed by the elastic member 2b (described later) expanding and contracting to change the distance x between the weight member 2a and the metal layer 2c. In other words, the vibration sensor 2 functions as a radio wave absorber, and is configured so that the reflection loss of radio waves can be changed by the vibration of the vibration sensor 2. The vibration sensor 2 is a suitable sensor for the frequency band of 15 GHz or more (wavelength band of radio waves of 15 GHz or more) explained in "1-1-2-1. Transmitting unit 120". Furthermore, the vibration sensor 2 does not require power (power source, battery), is applicable to a high frequency band of radio waves (wavelength of the applied radio waves is short), and can be made smaller and thinner. For example, the vibration sensor 2 is 2 cm 3 It is possible to configure it in a size of about

[0033] 1-2-1. Housing 2A The housing 2A is a case that houses the vibration sensor main body 2B. The housing 2A may also be provided with an antenna to facilitate transmission of radio waves to the vibration sensor main body 2B.

[0034] 1-2-2. Vibration sensor body 2B As shown in FIGS. 2 and 3, the vibration sensor main body 2B is a vibration sensor for detecting vibration frequency, and includes a weight member 2a, a gas layer 2d, a metal layer 2c, and an elastic member 2b.

[0035] 1-2-2-1. Weight member 2a The weight member 2a has a resistive layer 2a1 and a dielectric layer 2a2. In addition, it is preferable that the weight member 2a further includes a metal weight (not shown). This allows the weight of the weight member 2a to be easily increased, making it easier to optimize the vibration of the weight member 2a. The location of the metal weight is not particularly limited, but it may be embedded inside the weight member 2a or attached to at least one of the side, top, and bottom surfaces of the weight member 2a. When attached to the top or bottom surface, it is preferable to place it on the edge of these surfaces so as not to interfere with radio waves.

[0036] The resistive layer 2a1 is laminated on the dielectric layer 2a2. The resistive layer 2a1 may be made of a material such as a conductive organic polymer film, a sputtered film, or a vapor-deposited film. The resistive layer 2a1 may also be made of a material containing a carbon material such as a carbon microcoil, a carbon nanotube, or graphene.

[0037] The resistive layer 2a1 is a layer formed as a so-called solid layer. In other words, the resistive layer 2a1 has a sheet-like structure in which the entire region inside the outer edge of the resistive layer 2a1 is filled with the constituent material of the resistive layer 2a1.

[0038] The thickness (μm) of the resistance layer 2a1 is specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, and may be within a range between any two of the numerical values ​​exemplified here.

[0039] Furthermore, the resistance value (Ω / sq) of the resistive layer 2a1 is specifically, for example, 20, 30, 40, 50, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, and may be within a range between any two of the values ​​exemplified here.

[0040] In the embodiment, the resistive layer 2a1 and the dielectric layer 2a2 are each formed of a single layer, but this is not limitative and these layers may be formed of multiple layers (multiple layers).

[0041] The dielectric layer 2a2 can support the resistive layer 2a1. Various dielectric materials can be used for the dielectric layer 2a2. The dielectric layer 2a2 can be configured to include a polymeric material. Examples of the polymeric material include synthetic resins (including thermoplastic elastomers) such as polyvinyl chloride, polyvinylidene fluoride, acrylic resin, ethylene-vinyl acetate copolymer, polyurethane, acrylic urethane resin, ionomer, polyolefin, polypropylene, polyethylene, silicone resin, polyester, polystyrene, polyimide, polyamide, polysulfone, polyethersulfone, and epoxy resin, or synthetic rubbers such as polyisoprene rubber, polystyrene-butadiene rubber, polybutadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, butyl rubber, acrylic rubber, ethylene-propylene rubber, and silicone rubber. These materials can be used alone or in combination to form the polymeric material. The dielectric layer can also be made of materials such as glass, titanium oxide, alumina, and barium titanate.

[0042] The relative dielectric constant of the dielectric layer 2a2 can be set appropriately, and specifically, for example, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, or may be within a range between any two of the values ​​exemplified here.

[0043] The thickness (μm) of the dielectric layer 2a2 can be, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1500, 2000, 2500, 3000, 4000, 4500, 5000, 6000, 7000, 8000, 9000, or 10000, and may be within a range between any two of the numerical values ​​exemplified here.

[0044] 1-2-2-2. Elastic member 2b The elastic member 2b is provided in the gas layer 2d. One side of the elastic member 2b is connected to the weight member 2a, and the other side is connected to the metal layer 2c. In the embodiment, the elastic member 2b can be formed of, for example, a small spring member made of metal or resin.

[0045] The vibration sensor 2 has a plurality of elastic members 2b (four in this embodiment). The elastic members 2b are connected to the edge portions of the weight member 2a. More specifically, the elastic members 2b are connected to the corner portions of the dielectric layer 2a2 of the weight member 2a. This makes it difficult for the elastic members 2b to interfere with the radio waves that pass through the weight member 2a, allowing them to smoothly reach the metal layer 2c and be reflected.

[0046] 1-2-2-3. Metal layer 2c The metal layer 2c functions as a reflective layer that reflects radio waves. That is, the metal layer 2c is configured to reflect radio waves that have passed through the weight member 2a and the gas layer 2d. The metal layer 2c is directly or indirectly connected to the housing 2A, and is fixed to the housing 2A as a single unit.

[0047] The metal layer 2c preferably has a low resistance value, and for example, a metal material (such as copper or silver, which have high conductivity) can be used as the metal layer 2c. The metal layer 2c has a mesh structure. In other words, the metal layer 2c does not have a so-called solid structure, but has a mesh structure, which forms openings and ensures a certain degree of transparency. Note that the metal layer 2c may have a so-called solid structure instead of a mesh structure.

[0048] The thickness (μm) of the metal layer 2c can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900, or 1000, and may be within a range between any two of the numerical values ​​exemplified here.

[0049] 1-2-2-4. Gas layer 2d A gas layer 2d is disposed between the weight member and the metal layer. The gas layer 2d of the vibration sensor 2 enables the weight member 2a to vibrate. In the embodiment, the gas layer 2d is made of air, that is, the gas layer 2d is an air layer, but it may be a gas other than air.

[0050] 2. Operation explanation The transmitting unit 120 of the transmitting / receiving device 1 transmits a first radio wave w1 to the vibration sensor 2. The transmitting unit 120 may be configured to continuously transmit the first radio wave w1, or may be configured to transmit the first radio wave w1 at a predetermined timing or at a predetermined time in order to reduce power consumption. The first radio wave w1 propagates through space and reaches the vibration sensor 2. A portion of the first radio wave w1 as an incident wave is reflected by the resistive layer 2a1, and the other portion of the first radio wave w1 as an incident wave (the passing wave w3) passes through the resistive layer 2a1 and further passes through the dielectric layer 2a2 and the gas layer 2d. The passing wave w3 is reflected by the metal layer 2c and becomes the reflected wave w4.

[0051] Here, the phase of the reflected wave w4 has changed after being reflected by the metal layer 2c. Therefore, the reflected wave w4 interferes with the transmitted wave w3 in the dielectric layer 2a2 and the gas layer 2d and is attenuated, and the reflected wave w4 also interferes with the first radio wave w1, which is the incident wave, and is attenuated. The second radio wave w2, which is the radio wave returning to the transmitter / receiver 1, is composed of waves reflected by the resistive layer 2a1 and the metal layer 2c, and due to this attenuation effect, its power is lower than that of the first radio wave w1. In other words, the vibration sensor main body 2B functions as a radio wave absorber, and functions to absorb part of the power of the first radio wave w1 by causing radio waves to interfere with each other.

[0052] The receiving unit 121 of the transmitting / receiving device 1 receives the second radio wave w2 via the antenna unit 1C. Then, the frequency acquiring unit 122 calculates the return loss based on the first power P1 of the first radio wave w1 and the second power P2 of the second radio wave w2, and calculates the distance x based on this return loss. In the example of the embodiment, the first power P1 of the first radio wave w1 is a predetermined and known value, and therefore the value stored in the storage unit 11 can be used. The second power P2 can be obtained using a power detection circuit (not shown). The return loss is given by -10Log(P2 / P1). The distance x can be obtained using a relationship (either a table or a relational expression) such as the graph shown in Fig. 6. In other words, since the frequencies of the first radio wave w1 and the like are predetermined and known, the distance x can be obtained by using the obtained return loss.

[0053] If the vibration frequency detection system 100 includes the notification unit 123, the notification unit 123 notifies the user of information relating to the vibration of the vibration sensor 2 acquired by the vibration frequency acquisition unit 122.

[0054] In this way, in the vibration frequency detection system 100 equipped with the vibration sensor 2 according to the embodiment, the elastic member 2b expands and contracts, changing the distance between the weight member 2a and the metal layer 2c, thereby changing the reflection loss of radio waves. Since the reflection loss of radio waves is used to detect the vibration frequency, there is no need for, for example, a wireless circuit board, a power circuit and a power source (battery) to drive it, etc., and the system can be made smaller and thinner.

[0055] Various embodiments are exemplified below, and the embodiments shown below can be combined with each other. [Appendix 1] A vibration sensor for detecting a vibration frequency, The device includes a weight member, a gas layer, a metal layer, and an elastic member, the weight member has a resistive layer and a dielectric layer; the gas layer is disposed between the weight member and the metal layer; the elastic member is provided in the gas layer, and one side of the elastic member is connected to the weight member and the other side is connected to the metal layer; the vibration sensor is configured to change a reflection loss of radio waves by the elastic member expanding and contracting to change a distance between the weight member and the metal layer, A vibration sensor, wherein the reflection loss is based on a first power of a first radio wave incident on the weight member and a second power of a second radio wave that is incident on the weight member, reflected by the metal layer, and radiated from the weight member. [Appendix 2] 10. The vibration sensor of claim 1, The vibration sensor, wherein the resistive layer is laminated on the dielectric layer. [Appendix 3] 10. The vibration sensor according to claim 1, A plurality of the elastic members are provided, A vibration sensor, wherein a plurality of the elastic members are connected to edge portions of the weight member. [Appendix 4] A vibration sensor according to any one of Supplementary Note 1 to Supplementary Note 3, The vibration sensor, wherein the metal layer has a mesh structure. [Appendix 5] A vibration sensor according to any one of Supplementary Note 1 to Supplementary Note 4, The vibration sensor, wherein the weight member further includes a metal weight. [Appendix 6] A vibration frequency detection system having the vibration sensor according to any one of Supplementary Note 1 to Supplementary Note 5, The device includes a transmitter, a receiver, and a frequency acquisition unit, the transmitter is configured to be able to transmit the first radio wave to the vibration sensor; the receiving unit is configured to be able to receive the second radio wave from the vibration sensor, The frequency acquisition unit acquires the frequency using the reflection loss based on the first power of the first radio wave and the second power of the second radio wave. [Appendix 7] 7. The frequency detection system of claim 6, A vibration frequency detection system, wherein the transmitter, receiver, and vibration frequency acquisition unit are provided in a housing independent of the vibration sensor. [Appendix 8] 8. The vibration frequency detection system according to claim 6 or 7, A vibration frequency detection system, wherein the first radio wave transmitted by the transmitting unit is 15 GHz or higher. [Explanation of symbols]

[0056] 100: Vibration frequency detection system 1: Transmitting and receiving device 1A: Housing 1B: Information Processing Department 10: Communications Department 11: Storage section 12: Control section 120: Transmitter 121: Receiving unit 122: Frequency acquisition section 123: Information Department 13: Output section 14: Input section 1C: Antenna section 2: Vibration sensor 2A: Housing 2B: Vibration sensor body 2a: Weight member 2a1 :Resistance layer 2a2: Dielectric layer 2b: Elastic member 2c: Metal layer 2d: Gas layer w1: First radio wave w2: Second radio wave w3: Passing wave w4 :Reflected wave

Claims

1. A vibration sensor for detecting a vibration frequency, The device includes a weight member, a gas layer, a metal layer, and an elastic member, the weight member has a resistive layer and a dielectric layer; the gas layer is disposed between the weight member and the metal layer; the elastic member is provided in the gas layer, and one side of the elastic member is connected to the weight member and the other side is connected to the metal layer; the vibration sensor is configured to change a reflection loss of radio waves by the elastic member expanding and contracting to change a distance between the weight member and the metal layer, A vibration sensor, wherein the reflection loss is based on a first power of a first radio wave incident on the weight member and a second power of a second radio wave that is incident on the weight member, reflected by the metal layer, and radiated from the weight member.

2. 2. The vibration sensor according to claim 1, The vibration sensor, wherein the resistive layer is laminated on the dielectric layer.

3. 3. The vibration sensor according to claim 1, A plurality of the elastic members are provided, A vibration sensor, wherein a plurality of the elastic members are connected to edge portions of the weight member.

4. 3. The vibration sensor according to claim 1, The vibration sensor, wherein the metal layer has a mesh structure.

5. 3. The vibration sensor according to claim 1, The vibration sensor, wherein the weight member further includes a metal weight.

6. A vibration frequency detection system having the vibration sensor according to claim 1 or 2, The device includes a transmitter, a receiver, and a frequency acquisition unit, the transmitter is configured to be able to transmit the first radio wave to the vibration sensor; the receiving unit is configured to be able to receive the second radio wave from the vibration sensor, The frequency acquisition unit acquires the frequency using the reflection loss based on the first power of the first radio wave and the second power of the second radio wave.

7. 7. The vibration frequency detection system according to claim 6, A vibration frequency detection system, wherein the transmitter, receiver, and vibration frequency acquisition unit are provided in a housing independent of the vibration sensor.

8. 7. The vibration frequency detection system according to claim 6, A vibration frequency detection system, wherein the first radio wave transmitted by the transmitting unit is 15 GHz or higher.

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