Power supply device

Abstract

This antenna device comprises a rectifier circuit for receiving radio waves in space or the field energy of a quasi-electrostatic field (near field) and performing rectification into direct current from an alternating current signal, said antenna device having: an antenna unit constituted by a first antenna element, which is a conductor in contact or connected with an industrial product metal part; and a second antenna element, which is a separate conductor from the first antenna element and is provided to not be electrically connected with the industrial product metal part. Of the alternating current signals outputted from the antenna unit, the input line outputted to the rectifier circuit unit from the first antenna element is connected to the rectifier circuit. FIG. 2:

Description

Technical Field

[0001] The present technology relates to a device having an energy harvesting function. Power supply

Background Art

[0002] Converting the energy of radio waves such as broadcast waves existing around us into electric power (energy harvesting) is considered. In the case of environmental power generation, the current flowing through the circuit via the antenna is rectified to direct current and converted into electrical energy. A diode is used to rectify the radio wave to direct current. An antenna with a rectifying circuit is called a rectenna.

[0003] Non-Patent Document 1 describes increasing the efficiency of a rectenna by using a high-impedance antenna to receive the 470 - 600 MHz band of terrestrial digital broadcasting and increasing the excitation voltage of the rectifier.

[0004] Non-Patent Document 2 describes the measurement results of the power flux density of V-High multimedia broadcasting (208.5 - 222 MHz), terrestrial digital broadcasting (470 - 710 MHz), and 800 MHz band mobile phone base stations (860 - 890 MHz), as well as the evaluation of antennas for electromagnetic wave recovery.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Both of the above-mentioned Non-Patent Document 1 and Non-Patent Document 2 target only the electromagnetic energy of radio waves propagating in the air, design an antenna according to the frequency, and have a matching section for impedance matching. Such a configuration has a problem that it can only receive at the matched frequency and the obtained power becomes extremely small. In particular, an antenna is separately required according to the frequency to be received, and to receive a broadcast wave, a size of about half of the wavelength is required. If it is made small, the reception efficiency may decrease, and the application range has been very limited. That is, in order to receive power over a wide frequency range, a plurality of antennas of sizes corresponding to the frequencies that can be received are required, and it is necessary to install those antennas separately.

[0007] Therefore, the object of the present technology is to obtain a larger received power by capturing the electric field energy of a quasi-electrostatic field (near field) in addition to radio waves existing over a wide range, with a configuration different from that which converts the energy of radio waves using a conventional receiving antenna. Power supply To provide a device.

Means for Solving the Problems

[0008] This technology receives radio waves and the electric field energy of a quasi-electrostatic field (near field) in space, An antenna unit composed of a first antenna element and a second antenna element, and includes a rectifier circuit for rectifying an AC signal to DC, The first antenna element is Industrial product of Contacted or connected to a metal part For using the metal part of an industrial product as an antenna Is a conductor ri , The second antenna element isA conductor different from the first antenna element, an industrial product of Provided so as not to be electrically connected to the metal part Constitute an electric field by being capacitively coupled to the ground of the ground or grounded to the ground by a cable, The antenna unit receives electric field energy and converts it into electric power, Among the AC signals output from the antenna unit, the input line output from the first antenna element to the rectifier circuit unit is connected to the rectifier circuit ru, It is a power supply device.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] The embodiments described below are preferred specific examples of the present technology and are subject to various technically preferable limitations. However, the scope of the present technology is not limited to these embodiments in the following description, unless otherwise specified to limit the present technology. Also, in the following description, the same names and reference numerals indicate the same or equivalent components, and duplicate descriptions are omitted as appropriate.

[0011] This technology has a metal part where electric field energy is induced, such as metal parts (iron, aluminum, copper, metal alloys, etc.) in common industrial products, vehicles, vending machines, refrigerators, microwave ovens, metal racks, guardrails, postal posts, traffic lights, etc. As an antenna, it can receive the electric field energy of radio waves and quasi-electrostatic fields (near fields) in space. That is, in a floating state in space, if there is metal, various alternating current powers (alternating currents) flow on the metal surface. Therefore, this metal is regarded as an antenna and this power is efficiently converted into energy.

[0012] For example, electric field energy is induced in metal parts (iron, aluminum, copper, metal alloys, etc.) such as common industrial products, vehicles, vending machines, refrigerators, microwave ovens, metal racks, guardrails, postal posts, traffic lights, etc. This technology enables such industrial product metal parts to be used as an antenna to receive the electric field energy of radio waves and quasi-electrostatic fields (near fields) in space. That is, in a floating state in space, if there is metal, various alternating current powers (alternating currents) flow on the metal surface. Therefore, this metal is regarded as an antenna and this power is efficiently converted into energy. Note that the industrial product metal parts are metal parts other than those of industrial products designed as antennas.

[0013] In the input terminal part that is in contact with or connected to the industrial product metal part and uses the industrial product metal part itself as an antenna, in the connection with the subsequent rectifier circuit, the impedance for reception should be higher. In particular, without providing a matching circuit adjusted to the frequency, it is connected in series, and rectified by a diode with a very small reverse current with respect to the forward current. As a result, in addition to conventional radio waves, it is possible to efficiently receive the power of quasi-electrostatic fields (near fields), which are not radio waves such as 50 / 60 Hz leaking from a very small power source in terms of frequency.

[0014] Thus, between the input terminal portion connected to the metal part of the industrial product and the rectifier circuit, there is no need to consider the antenna shape and the matching circuit becomes unnecessary. As a result, in the first method, the ground of the antenna device is capacitively coupled to the ground of the ground or grounded to the ground by a cable or the like to form an electric field, so that it is possible to capture the electric field energy in the quasi-electrostatic field other than radio waves. Also, in the second method, a separate antenna element different from the ground of the antenna device is capacitively coupled to the ground of the ground or grounded to the ground by a cable or the like to form an electric field, so that it is possible to capture the electric field energy in the quasi-electrostatic field other than radio waves. That is, it is possible to receive the power and noise leaking from the power cord or the inverter and convert them into energy. This technology can increase the received power by being able to receive a wide range of electric field energy. The quasi-electrostatic field is a voltage phenomenon that does not have the property of propagating like a radiated electromagnetic field, so-called radio waves, and is distributed like electrostatic charging near humans, vehicles, and substances. While the electrostatic field is regarded as having zero time variation, the quasi-electrostatic field has frequency components and is accompanied by time variation.

[0015] FIG. 1 shows an embodiment of an antenna device having an energy harvesting function according to the present technology. Electric field energy is received by an antenna unit 1a composed of a first antenna element and a second antenna element, and the output of the antenna unit 1a is supplied to a rectifier circuit 2. The antenna unit 1a and the rectifier circuit 2 constitute the antenna device 1.

[0016] The output of the rectifier circuit 2 is supplied to a charger 3. A storage element 4 is connected to the charger 3. The storage element 4 is charged by the charger 3. The charger 3 may control the discharge of the storage element 4. The antenna device 1, the charger 3, and the storage element 4 constitute a receiving device. A load 5 is connected to the storage element 4. The load 5 operates by the power stored in the storage element 4. The load 5 is a microcomputer, a wireless communication unit, a sensor, or the like. The output of the sensor is wirelessly transmitted under the control of the microcomputer.

[0017] The antenna device 1 is composed of a first antenna element and a second antenna element that are in contact with a metal. Regarding an example of the antenna device 1, a plan view (FIG. 2A), a sectional view (FIG. 2B), a sectional view (FIG. 2C), a plan view (FIG. 3A), a sectional view (FIG. 3B), and a substrate diagram (described with reference to FIGS. 5 and 6) on which a rectifying circuit 2 (described later) is mounted will be described. As shown in FIGS. 2A, 2B, 2C, 3A, and 3B, a first antenna element 11 that is in contact with or connected to an industrial product metal part is configured in a plate shape (patch shape). The antenna element 11 is a plate-shaped one made of a conductor such as gold, silver, aluminum, copper, iron, nickel, or an alloy. The contact surface of the antenna element 11 with the metal may be resin-coated. The antenna element 11 is shaped like a line, a pin, a hemisphere, or unevenness according to the shape of the industrial product metal part. The industrial product metal part and the antenna element 11 are brought into contact with or connected to each other by methods such as welding, mechanical coupling (crimping, etc.), adhesion with a conductive adhesive, or attachment to a ferrous material using magnetism such as a magnet. In addition, as the antenna element 11, for example, a conductive resin or a conductive rubber in which carbon or metal is blended may be used. By using a conductive resin, for example, electrodes of various shapes can be easily formed. Also, by using a conductive rubber, it is possible to configure electrodes that can be elastically deformed or have high adhesion. In addition, the material of the antenna element 11 is not limited, and the above-described materials may be used alone, or electrodes may be configured by combining each material.

[0018] Note that as long as the antenna element 11 can be capacitively coupled to the metal with a space or an insulator intervening therebetween. FIG. 4 shows a desk lamp 6 provided with a fluorescent lamp 7. The antenna device 1 is attached to the main body 8 in a state of being housed, for example, in a resin case.

[0019] A circuit section such as an inverter is mounted on a substrate 9 housed in a resin case of the main body 8. The inverter temporarily converts a commercial power supply of 50 Hz or 60 Hz into direct current, and further converts it into a high-frequency signal of 20 to 50 kHz to light up a fluorescent lamp 7. This lighting method has no flicker peculiar to fluorescent lamps compared to lighting according to the frequency of the commercial power supply. Space noise is generated from the circuit section as indicated by the arrow. The antenna device 1 is spatially coupled to a substrate on which a circuit section such as an inverter is mounted and can induce a voltage by the space noise. For example, when the fluorescent lamp is turned on, it was experimentally confirmed that a voltage of about 4.4 V is induced.

[0020] In FIGS. 2B and 2C, for example, a plate-shaped (patch-shaped) antenna element 11 and an equipment substrate (circuit board) 12 are arranged to face each other, and a dielectric plate 13 is interposed between the antenna element 11 and the equipment substrate 12. The space between the antenna element 11 and the equipment substrate 12 may be used as a space without providing the dielectric plate 13.

[0021] In order to electrically connect the antenna element 11 and the equipment substrate 12, one end of the antenna element 11 and a conductive pin 14 are electrically connected, the other end of the conductive pin 14 penetrates the equipment substrate 12, and is soldered to a signal path electrode on the back surface of the equipment substrate 12. The antenna section 1a is constituted by a ground formed by copper foil patterns of the antenna element 11 and the equipment substrate 12. The ground is a second antenna element. Such an antenna section 1a has a structure of a T-shaped antenna with a flat plate as the antenna element. The connection portion between the signal path electrode of the equipment substrate 12 and the conductive pin 14 serves as a feeding point 15 of the antenna. A circuit section 16 is provided, for example, on the back surface of the equipment substrate 12.

[0022] The antenna device having the above-described configuration is housed in a case 17. Contact surfaces of the case 17 other than the antenna element 11 are made of an insulating material such as resin. Also, side surfaces of the case, opposite surfaces of the case, etc., other than the contact surfaces with metals for which energy is to be taken in are made of an insulating material.

[0023] FIG. 2C shows a configuration in which the case 17 is composed of a non-metal case 17A such as resin and a metal case 17B. It is also possible to adopt a configuration in which the ground 19 on either the upper or lower surface of the device substrate 12 is electrically connected to the case 17B. That is, the non-metal case 17A of the insulating material provided with the antenna element 11 and the metal case 17B constituting the opposite surface may be connected by a connecting portion 22 such as a screw, and the case 17B and the ground 19 of the device substrate 12 may be connected by a wire 23.

[0024] Also, as shown in FIGS. 3A and 3B, an insulated coated cable 24 may be connected to the ground 19 formed by the copper foil pattern of the device substrate 12 with solder or the like so as to be grounded to the ground. In this embodiment, the antenna element 11 is configured as a plate, and is configured to be in contact with or connected to the metal part of the industrial product. However, for the connection between the antenna element 11 and the feeding point 15, it is also possible to directly connect using a coated cable or the like insulated from the metal part of the industrial product.

[0025] As shown in FIG. 5, a ground 19 formed by a copper foil pattern is formed on the circuit board 12, and the antenna unit 1a is constituted by the antenna element 11 and the ground 19 formed by the copper foil pattern of the device substrate 12. The ground 19 is the second antenna element. In addition, an electrostatic protection component, for example, a varistor 18, is inserted between the antenna element 11 in contact with or connected to the metal and the ground formed by the copper foil pattern of the receiving device as an electrostatic countermeasure. The varistor 18 may be connected between the output terminal 34a and the ground 19.

[0026] The circuit section 16 includes a rectifying circuit 2. The rectifying circuit 2 is made not to overlap with the ground 19 formed by the copper foil pattern of the device substrate 12. The input line output from the antenna element 11 to the rectifying circuit 2 is connected in series to the rectifying circuit without passing through a matching circuit. A charger 3 and a storage element 4 (not shown) may be included in the circuit section 16, or may exist separately.

[0027] FIG. 6 shows the configuration of the device substrate 12 corresponding to FIGS. 3A and 3B. The ground 19 (shown as the hatched area) formed by the copper foil pattern of the device substrate 12 is grounded to the ground ground through the insulated coated cable 24. The ground ground may function as a low-potential ground such as a wide conductive plate including the ground. Note that the varistor 18 may be connected between the output terminal 34a and the ground 19.

[0028] Next, as shown in FIG. 7, a separate second antenna element 20 (shown as the hatched area) formed by a copper foil pattern may be configured on the substrate. In this case, the separate second antenna element 20 needs to be prevented from contacting or connecting to the metal part of the industrial product that is intended to capture energy. Also, as shown in FIG. 8, an insulated coated cable 25a may be further connected to the ground 19 (shown as the hatched area) formed by the copper foil pattern of the device substrate 12 to be grounded to the ground ground. Also, in FIGS. 7 and 8, although it is created on a separate substrate, it may be formed on a metal part such as a housing configured not to contact the metal so as to be opposite to the metal contact surface of the receiver. Also in this case, for the antenna element 11 that contacts the metal, as an electrostatic countermeasure, it is also possible to insert an electrostatic protection component, for example, a varistor 21 between the ground of the receiving device. Note that the varistor 21 may be connected between the output terminal 34a and the ground 19.

[0029] Furthermore, as shown in FIG. 9, for the antenna element 11 in contact with the metal, as an electrostatic countermeasure, an electrostatic protection component such as a varistor 21 is inserted between the antenna element 20, and an insulated covered cable 25b is connected to the antenna element 20 and grounded to the ground. In this case, the antenna element 20 can extract power much larger than the electric field created with the ground of the ground by capacitive coupling. When it is assumed that power is to be extracted from metal products such as an electric range or a refrigerator in the room, as an electrostatic countermeasure, it is required to drop it to the ground. When power is to be extracted from the metal part of such a product, as described above, it is necessary to connect with an insulated covered cable or the like to cope with it. Note that the varistor 21 may be connected between the output terminal 34a and the ground 19.

[0030] FIGS. 10 and 11 are diagrams showing modified examples of FIGS. 5 and 7. That is, when grounding is directly taken from the metal part of the industrial product to the ground with an insulated covered wire, it is grounded through an electrostatic protection component such as a varistor 18 in the middle of the insulated covered wire. In the case of an existing electrical product that requires a separate ground connection, the above-described configuration is used.

[0031] Another configuration of the second antenna element 20 is shown in FIG. 12. FIG. 12A shows the configuration of the meander line 20a, and FIG. 12B shows the configuration of the coil 20b. The coil 20b may be configured as a chip coil. FIG. 12C shows a configuration having an inductor 20c at the tip. These configurations can reduce the occupied area, increase the antenna length, and increase the induced voltage.

[0032] There is a very large amount of electric field energy around the body, but it can be divided into a low-frequency component and a high-frequency component. For example, the leakage electric field (50 Hz / 60 Hz) from the household AC power supply, the noise existing near the personal computer, etc. are low-frequency components. These are called quasi-electrostatic fields (near fields). On the other hand, radio broadcasts (AM / FM), television broadcasts, mobile phone radio waves, etc. are high-frequency components. These are called radio waves (far fields).

[0033] As shown in FIG. 13, the antenna element 11 of the antenna device 1 described above is brought into contact with the metal of an industrial product metal part, for example, a metal rack 91. The antenna element 11 is attached to one surface of the metal rack 91. Electrically, the metal part and the antenna element 11 are brought into contact by capacitive coupling. By using the metal part of the metal rack 91 as an antenna, the antenna device 1 can capture the energy of both a low-frequency quasi-electrostatic field such as noise and radio waves such as broadcast waves.

[0034] As the antenna device 1, it is preferable that the antenna element 11 is directly connected to the industrial product metal part. However, in this example, basically, contact is made by a surface so as to increase the capacitance. If it is in contact with or connected to the metal part, in the case of contact, in addition to a planar shape, a pin structure, a hemispherical shape, or a structure that fits with unevenness may be used. In the case of connection, it may be connected by screwing, soldering, welding, etc., directly or via an insulator (or air) such as an insulated coating cable or conductive rubber. The antenna unit 1a constituted by the antenna element 11 in contact with the metal and the ground electrode 19 of the device substrate 12 or a separate second antenna element 20 can receive the electric field energy and generate electric power.

[0035] As shown in FIG. 14, for example, the metal rack 91 exists in an electrically floating state on a carpet that is an insulating material. In a state where the antenna device 1 (hatched portion) including the antenna unit 1a is attached, the circuit configurations of FIGS. 5 and 7 can be adopted. In this case, it can be considered that a large antenna unit is formed by capacitive coupling between the ground 19 of the device substrate 12 (not shown here) or a separate second antenna element 20 (not shown here) and the ground ground (GND1). This antenna unit can receive a low-frequency quasi-electrostatic field.

[0036] When the circuit configuration is as shown in Fig. 10, the effect of capturing energy from space is further enhanced. That is, it can be realized by installing a separate second antenna element 20 to the ground ground (GND) in, for example, an earthed socket via an insulated cable 25c.

[0037] Furthermore, as shown in Fig. 16, the antenna device 1 (hatched portion) including the antenna section 1a may be connected to the metal plate 93 by the insulated cable 92, and the metal plate 93 may be brought close to the ground ground (GND1) so that the antenna device is capacitively coupled to the ground ground (GND1).

[0038] Next, the configuration examples of the embodiments of Figs. 10 and 11 are shown in Figs. 17A and 17B. When grounding the earth cable 82 attached to the microwave oven 81, an electrostatic protection component 83 is provided between the earth terminal of the power socket. On the substrate of the electrostatic protection component 83, a screw portion 85 for connecting the earth cable 82, a varistor 84 for electrostatic protection, etc. are provided, and the earth cable 82 is soldered onto the substrate.

[0039] In this way, the antenna device 1 is capable of receiving electric field energy in a wide frequency range. Therefore, with the antenna device of the present technology this time, it is possible to easily capture wide electric field energy just by contacting the metal. Furthermore, when it is desired to increase the capture amount, connection such as soldering to the metal part of the industrial product is preferable. Also, when the metal rack is made of iron, the connection may be maintained with a magnet.

[0040] An example of the rectifier circuit 2 is shown in Fig. 18. When dealing with a small voltage such as energy harvesting, it is not impossible to rectify it with a normal rectifier circuit, but a certain level of voltage is required to store energy quickly. Therefore, it is necessary to boost the voltage and rectify it, such as in a voltage doubler circuit. Thus, a full-wave quadruple voltage rectifier circuit is configured with input capacitors 26 and 27 connected to the antenna section 1a, diodes 28, 29, 30, and 31, and capacitors 32 and 33. DC output is provided from output terminals 34a and 34b at both ends of the series connection of capacitors 32 and 33. In this configuration, capacitors 32 and 33 not only boost the voltage but also actually store current, so the capacitance of this part should be relatively large and the leakage current should be small.

[0041] In this example, it is a full-wave quadruple voltage rectifier circuit, but it may also be a rectifier circuit incorporating a normal single half-wave rectifier circuit, full-wave rectifier circuit, voltage doubler rectifier circuit, or Cockcroft-Walton circuit. Also, in terms of efficiency, the full-wave rectifier circuit can increase the voltage of the AC signal and capture all of it. Therefore, in the diodes adopted for rectification this time, even including the diode loss, the full-wave rectifier circuit yielded better results. Although it is a two-stage quadruple voltage full-wave rectification, if you want to increase the extracted voltage, you may further increase the number of stages.

[0042] An example of the values of each element is shown below. Capacitors 26, 27: 0.22 μF, 32, 33: 47 μF Diodes 28, 29, 30, 31: 1N60 (silicon)

[0043] In the case of the quadruple voltage rectifier circuit described above, it is important that the leakage current of the diode during reverse bias is very small. If there is a leakage current, a full-wave rectifier circuit is suitable. Another example of the rectifier circuit 2 (full-wave rectifier circuit) is shown in FIG. 19. As shown in FIG. 19, diodes 61 and 64 are connected in series, and diodes 63 and 62 are connected in series. The connection point of the anode of diode 61 and the cathode of diode 64 is connected to the first antenna element 11, and the connection point of the anode of diode 63 and the cathode of diode 62 is connected to the second antenna element 20. The connection point of the cathode of diode 61 and the cathode of diode 63 is connected to one output terminal 34a via a reverse current prevention diode 65, and the connection point of the anode of diode 64 and the anode of diode 62 is connected to the other output terminal 34b. A static electricity countermeasure varistor 66 and an IC protection Zener diode 67 (for example, Zener voltage is 6.5V) are connected in parallel between the output terminals 34a and 34b.

[0044] Although it is composed of discrete diodes, it may also be composed of a dedicated IC. The results of measuring the forward voltage Vf and reverse current Is of the diodes used in the rectifier circuit 4 are shown in FIG. 20 and Table 1. As the diode part number 1N60, those made of silicon and germanium were measured, and for the other part number ISS108, those made of germanium with different manufacturers were used for evaluation. In FIG. 20, curve 42 is the characteristic of 1N60 (silicon), curve 41 is the characteristic of 1N60 (germanium), and curve 43 is the characteristic of ISS108 (germanium).

[0045]

Table 1

[0046] The current that flows when a voltage is applied in the reverse direction of the diode is the reverse current Is. The measurement data in Table 1 is the data when 10V is applied in the reverse direction of the diode. The forward voltage Vf is the voltage when the forward current (1mA) starts to flow through the diode.

[0047] When rectifying the output of the above-described antenna unit 1a, it was found that the diode 1N60 (silicon), which allows no current to flow in the reverse direction, can capture more power than a diode with a lower voltage at which current starts to flow in the forward direction. Since the input to be rectified is alternating current, the forward voltage Vf of the diode and the reverse current Is when a voltage equal to Vf is applied in the reverse direction. Given that Table 1 shows data for 10V, when calculating the reverse current Is when a voltage equal to Vf is applied in the reverse direction, for 1N60 (silicon) it is 0.036 μA, for 1N60 (germanium) it is 0.21 μA, and for ISS108 (germanium) it is 0.5 μA. Therefore, the ratio of the reverse current Is to the forward current (1 mA) / forward voltage Vf, when calculated, is 1 / 27778 for 1N60 (silicon), 1 / 4762 for 1N60 (germanium), and 1 / 2000 for ISS108 (germanium). That is, for the diode used in the rectifier circuit 2, it is necessary that the above ratio be greater than about 4700 times, and preferably, the above ratio is 10000 or more. As a result, among the three diodes cited as examples, 1N60 (silicon) has the most suitable characteristics.

[0048] Furthermore, considering the characteristics of the diode, the reverse current Is when a voltage is applied in the reverse direction should be small. Using the data for 10V, when calculating the reverse resistance value, for 1N60 (silicon) it is 100 MΩ, for 1N60 (germanium) it is 1.43 MΩ, and for ISS108 (germanium) it is 0.38 MΩ. That is, a larger resistance value for blocking the flow of current in the reverse direction is better. For the diode used in the rectifier circuit 2, it is necessary that the above resistance value be greater than 1.43 MΩ, and preferably, it is 10 MΩ or more. As a result, among the three diodes cited as examples, 1N60 (silicon) has the most suitable characteristics.

[0049] Considering such differences in the characteristics of the diodes, as shown in Fig. 21, it is also possible to provide two rectifier circuits 2a and 2b and divide the output of the antenna unit 1a into two frequency components by the diplexer 7. The low frequency component less than a predetermined frequency, for example less than 1 MHz, divided by the diplexer 7 is supplied to one rectifier circuit 2a and rectified. Also, the high frequency component equal to or higher than the predetermined frequency, for example 1 MHz or higher, is supplied to the other rectifier circuit 2b and rectified. The outputs of these rectifier circuits 2a and 2b are added by the adder circuit 8 and output.

[0050] The rectifying diode constituting the rectifier circuit 2a has characteristics suitable for rectifying an electrical signal generated from the quasi-electrostatic field of a low frequency component, for example, a characteristic that the reverse current Is at the forward voltage Vf is small. The rectifying diode constituting the rectifier circuit 2b has characteristics suitable for rectifying an electrical signal generated from the radio wave of the radiated electromagnetic field of a high frequency component, for example, a characteristic that the forward voltage is low. The diplexer 7 that separates the output signal of the antenna unit 1a is configured to have as little loss as possible. Note that 1 MHz of the predetermined frequency is an example, and it may be divided at different frequencies depending on the frequency characteristics of the diode, and the frequency division may be three or more.

[0051] The configuration of the antenna device when a full-wave rectifier circuit is used as the rectifier circuit will be described. Fig. 22 shows a configuration corresponding to the configuration of Fig. 6. Note that the varistor 18 may be connected between the output terminal 34a and the ground 19. Fig. 23 shows a configuration corresponding to the configuration of Fig. 7. Note that the varistor 21 may be connected between the output terminal 34a and the ground 19. Fig. 24 shows a configuration corresponding to Fig. 9. Note that the varistor 21 may be connected between the output terminal 34a and the ground 19. Thus, the full rectifier circuit 2 can be used in the same way as the voltage doubler rectifier circuit.

[0052] According to one embodiment of the present technology described above, by bringing an antenna element into contact with or connecting it to a metal, it becomes possible to capture the energy of the quasi-electrostatic field and radio waves generated in space. If the captured energy is rectified and stored in a power storage element such as a secondary battery, it can be used as a power source for indoor sensors and outdoor sensors.

[0053] As shown in FIG. 25, a full-wave rectifier circuit (composed of diodes 61 to 64 and Zener diodes 66, 67) is connected to the antenna device 1, and the output voltage of the full-wave rectifier circuit can be measured by a sensor with a high resistance (2 MΩ or more, preferably 10 MΩ), for example, a voltmeter 95. Also, the battery 96 is charged through the reverse current prevention diode 65 by the output of the full-wave rectifier circuit, and the output of the battery 96 is used as the power source for the voltmeter 95.

[0054] By using a sensor with a high resistance, it becomes possible to measure the voltage induced in the metal. And by analyzing the acquired data, it becomes possible to acquire the operating status of the motor and inverter of the device, etc. Thereby, the state of the device can be grasped, and an alert or the like can be issued before a failure.

[0055] As an example, an experiment was conducted by attaching an antenna device to the side of a refrigerator. Using the generated power of 4.4 V, a step-down DC-DC converter was used to step down the voltage from 3.7 V to 2.5 V to charge the battery. The results of checking the charging voltage and input voltage every certain period of time are shown in the graph of FIG. 26. It can be seen from this graph that the battery can be charged and the timing of the inverter being turned off can be detected.

[0056] Other embodiments of the present technology will be described with reference to FIGS. 27A, 27B, and 28. Other embodiments are those in which the present technology is applied to a vehicle (especially the vehicle body). As shown in FIG. 27A, when the antenna device 1 (hatched portion) is attached to the vehicle 71, in the configurations of FIGS. 5 and 7, it can be considered that a large antenna device 1 is formed by capacitive coupling between the ground of the device substrate 12 or a separate second antenna element 20 and the ground ground. This antenna device 1 can capture the energy of the quasi-electrostatic field and radio waves generated in the space, including receiving a low-frequency quasi-electrostatic field.

[0057] Generally, a vehicle (vehicle body) is made of metal, so static electricity is likely to be generated. Also, recently, in order to improve the wear resistance of tires, silica is mixed instead of conventional carbon. Since silica does not conduct electricity, measures such as providing a conductive slit 74 (shown hatched) in a part of the tire 73 are taken to release static electricity, as shown in an enlarged cross-section in FIG. 28. The conductive slit 74 has a structure for releasing the generated static electricity. However, since the contact area of the conductive slit 74 with the ground is limited, the tire has a resistance value of about 10 MΩ. That is, it has a circuit configuration grounded through a resistance as shown in FIG. 27B. Therefore, when viewed from the energy of the quasi-electrostatic field and radio waves generated in the space targeted this time, it is in a floating state in the space. Also, even when it is not completely insulated from the ground, in FIG. 19B, although it is an example of a resistance, the metal part (for example, the vehicle body) 72 and the ground may be coupled by an inductance component instead of a resistance.

[0058] By using such a large metal of the vehicle as an antenna in this way, it becomes possible to capture more energy of the quasi-electrostatic field and radio waves generated in the space. If the captured energy is rectified and stored in a power storage element such as a secondary battery, in the future, charging of components such as the vehicle key position detection sensor required for the vehicle will no longer be necessary.

[0059] This technology uses metals such as cars, vending machines, refrigerators, microwave ovens, metal racks, guardrails, postal posts, and traffic lights as antennas. Also, this antenna is made with the ground of the receiving device or a separate antenna, so that the receivable frequency is not restricted by the antenna shape. Further, by adopting a structure where the ground of the receiving device is capacitively coupled to the ground of the earth, it becomes possible to capture the electric field energy in the quasi-electrostatic field other than radio waves. That is, it enables the conversion of the power and noise leaking from the power cord or inverter into energy. In this way, the metal of the product is treated as one antenna element, and as an antenna, the power induced in the metal of the product itself can be captured between the metal and the ground of the receiving device.

[0060] In the case of assuming taking out power from metal products that need to be grounded for electrostatic protection, such as microwave ovens and refrigerators indoors, as shown in the examples of FIGS. 6, 8, 9, 10, and 11, as an electrostatic protection measure, an electrostatic protection component, for example, a varistor 21, is inserted between the antenna element 11, and the insulated coated cables 24, 25a, 25b are connected through the ground 19 of the device or the antenna element 20 and grounded to the ground of the earth, thereby enabling electrostatic protection.

[0061] Furthermore, in the example of FIG. 9, since the antenna element 20 is connected to the ground of the earth through an insulated coated cable, it becomes possible to extract power much larger than capacitive coupling. When taking out power from the metal part of such a product, as described above, it is necessary to connect with an insulated coated cable or the like for countermeasures.

[0062] Although the embodiments of the present technology have been specifically described above, the present technology is not limited to the above-described embodiments, and various modifications based on the technical idea of the present technology are possible. Further, the modified embodiments may be appropriately combined by arbitrarily selecting one or more of them. Further, the configurations, methods, processes, shapes, materials, numerical values, etc. of the above-described embodiments can be combined with each other as long as they do not deviate from the gist of the present technology. For example, the present technology may be combined with power generation using natural energy such as solar power generation, or a thermoelectric conversion element to store energy.

[0063] Next, as an application example of the receiving device according to the embodiment or the like, it can be used as a power supply device for electronic devices such as a temperature and humidity sensor and a vehicle position detection sensor.

[0064] FIG. 29 is a block diagram showing an application example in which the present technology is applied to a power supply for IoT (Internet of Things) for environmental monitoring or detection of device conditions. It has an illuminance sensor 51, a temperature, humidity and atmospheric pressure sensor 52, a BLE (Blue tooth (registered trademark) Low Energy) and an MCU (Microcontroller unit) 53, and these blocks (ICs) are connected by an I2C bus 54. As such a power supply for IoT, the antenna device 1 according to the present technology (a configuration including an antenna unit 1a and a rectifier circuit 2 as shown in FIG. 6) is applied.

[0065] In addition, when the rectifier circuit 2 uses a capacitor, for example, in the case of a voltage doubler rectifier circuit, it is important that the leakage current of the diode during reverse bias is very small. If there is a leakage current, a full-wave rectifier circuit is suitable. As for the diode characteristics, it is preferable that a large current can flow from a very small voltage of Vf. And in order to obtain a high voltage, it is desirable that the leakage current of the reverse voltage applied substrate is very small. When a circuit such as a quadruple voltage circuit is used, the leakage current at this time needs to be about 0.001 μA when a reverse voltage of 5 V is applied.

[0066] In addition, when the rectifier circuit 2 is a voltage doubler rectifier circuit or higher using a capacitor, it is important that the leakage current of the diode during reverse bias is very small. If there is a leakage current, a full-wave rectifier circuit is suitable. As for the diode characteristics, it is preferable that a large current can flow from a very low Vf voltage. Also, in order to obtain a high voltage, it is desirable that the leakage current of the reverse voltage applied substrate is very small. When using a circuit such as a quadruple voltage circuit, the leakage current at this time needs to be about 0.001 μA when a reverse voltage of 5 V is applied.

[0067] BLE is one of the extended specifications of Bluetooth (registered trademark) and enables communication with extremely low power. BLE and the MCU 53 can wirelessly transmit the detection data of the illuminance sensor 51 and the temperature, humidity, and atmospheric pressure sensor 52 to a mobile terminal such as a smartphone or a tablet.

[0068] The output terminals 34a and 34b of the rectifier circuit 2 are connected to the DC-DC converter 55 as a charger. The output of the DC-DC converter 55 charges a storage element, for example, a lithium-ion secondary battery 56. The output of the lithium-ion secondary battery 56 is supplied to the DC-DC converter 57 and the LDO (Low Dropout) 58.

[0069] The output of the DC-DC converter 57 is supplied as a power source to the illuminance sensor 51, the temperature, humidity, and atmospheric pressure sensor 52, BLE, and the MCU 53. Also, the output of the LDO 58 is supplied as a power source to BLE and the MCU 53. The LDO is a linear regulator that operates even with a low input-output potential difference. By operating with a low potential difference, it is possible to design with less energy loss and suppress heat generation. It is supplied to the AD conversion input of BLE and the MCU 53, and the output voltage of the secondary battery 56 is monitored by BLE and the MCU 53.

[0070] The antenna used for communication with the outside such as BLE described above is preferably a dipole structure with an antenna configuration that does not use the ground of the circuit board that is less affected by energy harvesting.

[0071] When the above-described power storage circuit unit is applied, it is also possible to charge the battery of the device that requires charging.

[0072] In addition, when it is used outdoors and exposed to wind and rain, waterproofing, dustproofing, and weather resistance to ultraviolet rays and the like are required. In the configurations of FIGS. 2 and 3, by coating the surfaces of the antenna element 11 and the case 17 or the cases 17A and 17B and the joint portion 22 when the case is separated (FIG. 2C) with a resin having water resistance and light resistance, it is also possible to improve the weather resistance of the antenna device 1.

[0073] Further, although this technology captures the energy of the electric field induced in the metal part of the device, when this effect is actively used, it can also be used as a power receiving device for wireless power supply.

[0074] A general configuration for increasing the output of the antenna device including the antenna unit 1a and the rectifier circuit 2 will be described with reference to FIGS. 30A and 30B. FIG. 30A shows a configuration in which the antenna devices 101, 102, and 103 are connected in series. The voltage VL applied to the load RL is (V1 + V2 + V3). FIG. 30B shows a configuration in which the antenna devices 101, 102, and 103 are connected in parallel. The current IL flowing through the load RL is (I1 + I2 + I3).

[0075] FIG. 31 shows a first embodiment for increasing the output voltage of the antenna device. A first antenna element 11 in contact with a metal is provided, and two second antenna elements 20A and 20B are provided with respect to the antenna element 11. The antenna elements 20A and 20B are, for example, another independent substrate, housing, etc. A rectifier circuit 2A for rectifying the output of the antenna section composed of the antenna elements 11 and 20A is provided, and a rectifier circuit 2B for rectifying the output of the antenna section composed of the antenna elements 11 and 20B is provided. The rectifier circuits 2A and 2B are connected in series, and an output line is derived from the series connection.

[0076] FIG. 32 shows the circuit connection of the first embodiment. It is an example using a full-wave rectifier circuit as the rectifier circuits 2A and 2B connected in series. The Zener diodes 66 and 67 are elements common to the two rectifier circuits 2A and 2B.

[0077] According to such a first embodiment, when an output voltage of, for example, 4V can be obtained by one antenna device, an output voltage of 8V can be obtained. By connecting two or more rectifier circuits in series, a larger output voltage can be obtained. The first embodiment is a suitable configuration in such a case because when the frequency of power supply noise etc. that induces voltage is low, it is not necessary to consider the distance between the antennas.

[0078] As shown in FIGS. 33 and 34, the second embodiment provides independent antenna elements 11A and 11B as the first antenna elements in contact with the metal. The antenna elements 11A and 11B are in contact with separate portions of the metal.

[0079] FIG. 34 shows the circuit connection of the second embodiment. It is an example using a full-wave rectifier circuit as the rectifier circuits 2A and 2B connected in series. The Zener diodes 66 and 67 are elements common to the two rectifier circuits 2A and 2B.

[0080] A third embodiment for increasing the output current of the antenna device is shown in FIGS. 35 and 36. A first antenna element 11 that contacts a metal is provided, and two second antenna elements 20A and 20B are provided with respect to the antenna element 11. The antenna elements 20A and 20B are, for example, another independent substrate, housing, or the like. A rectifier circuit 2A that rectifies the output of the antenna unit composed of the antenna elements 11 and 20A is provided, and a rectifier circuit 2B that rectifies the output of the antenna unit composed of the antenna elements 11 and 20B is provided. The rectifier circuits 2A and 2B are connected in parallel, and an output line is derived from the parallel connection.

[0081] FIG. 36 shows the circuit connection of the third embodiment. This is an example in which a full-wave rectifier circuit is used as the rectifier circuits 2A and 2B connected in parallel. The Zener diodes 66 and 67 are elements common to the two rectifier circuits 2A and 2B.

[0082] As shown in FIGS. 37 and 38, a fourth embodiment provides independent antenna elements 11A and 11B as the first antenna elements that are brought into contact with a metal. The antenna elements 11A and 11B are brought into contact with separate portions of the metal.

[0083] FIG. 38 shows the circuit connection of the fourth embodiment. This is an example in which a full-wave rectifier circuit is used as the rectifier circuits 2A and 2B connected in parallel. The Zener diodes 66 and 67 are elements common to the two rectifier circuits 2A and 2B.

[0084] The antenna elements 11, 11A, and 11B that contact the metal described above are connected to the connection points of the diodes 61a and 64a and the connection points of the diodes 61b and 64b, respectively, in order to be in the same phase. Also, the connection positions of the full-wave rectifier circuits are the same points. The antenna element connected to the metal element is connected to a position where the phases of the rectifier circuits are added together in order to be in the same phase.

[0085] Figures 39A and 39B, Figures 40A and 40B show examples of increasing the number of antennas in the present technology. When increasing the number of antennas of the same length, the voltage will decrease slightly. However, when it is desired to increase the current, the number of antenna elements may be increased. As shown in Figures 39A and 40A, by creating and connecting an antenna element 200 at the base of the antenna element 20, the current can be increased. When it is desired to increase both the voltage and the current, the length of the antenna element is made such that (the length of antenna element 20 < the length of antenna element 200). Also, as shown in Figures 39B and 40B, the antenna element 20 may be created on a substrate equipped with a rectifying circuit, and the antenna element 200 may be created separately, for example, on a substrate, a housing, a rod antenna, etc.

[0086] As described above, when an output current of, for example, 4 μA can be obtained by one antenna device, an output current of 8 μA can be obtained by connecting in parallel. Also, when it is desired to increase the voltage, for example, when it is desired to change the 4 V output to an 8 V output, it becomes possible by using a series circuit connection. In this way, by combining the above series and parallel circuits, it becomes possible to supply the necessary power to the subsequent stage.

[0087] In the circuit configuration described above, a capacitor may be connected in parallel to the Zener diode to smooth the voltage after rectification.

Description of Reference Numerals

[0089] 1 ··· Antenna device, 2, 2a, 2b ··· Rectifying circuit, 4 ··· Energy storage element, 7 ··· Diplexer, 11 ··· Antenna element, 12 ··· Equipment substrate, 15 ··· Feeding point, 91 ··· Metal rack, 71 ··· Vehicle

Claims

1. It receives the electric field energy of radio waves and quasi-electrostatic fields (near fields) in space, and includes an antenna unit composed of a first antenna element and a second antenna element, and a rectifying circuit for rectifying an alternating current signal to direct current. The first antenna element is in contact with or connected to a metal part of an industrial product, and is a conductor for using the metal part of the industrial product as an antenna. The second antenna element is a conductor different from the first antenna element, and is provided so as not to be electrically connected to the metal part of the industrial product, and is grounded to the ground by capacitive coupling, or is grounded to the ground by a cable to constitute an electric field. The antenna unit receives electric field energy and converts it into electric power. Among the alternating current signals output from the antenna unit, an input line output from the first antenna element to the rectifying circuit unit is connected to the rectifying circuit. A power supply device.

2. The rectifying circuit has a ratio of the forward current at the forward voltage of the diode for rectification to the reverse current when the voltage is applied in the reverse direction of at least 4700 times or more, or a resistance value obtained using the reverse current when 10 V is applied in the reverse direction of the diode for rectification is 1.4 MΩ or more. The power supply device according to Claim 1.

3. The power supply device according to Claim 2, wherein the diode is made of silicon.

4. The electric field energy of the quasi-electrostatic field is power or noise leaking from a power cord or an inverter. The power supply device according to Claim 1.

5. The power supply device according to Claim 1, wherein the input line is connected in series to the rectifying circuit.

6. The power supply device according to Claim 1, further comprising an electrostatic protection component.

7. The power supply device according to Claim 6, characterized in that it is grounded from the first antenna element via the electrostatic protection component.

8. The power supply device according to Claim 6, characterized in that it is grounded to the ground from the first antenna element via the electrostatic protection component using an insulated covered cable.

9. The power supply device according to Claim 1, further comprising a separation circuit for frequency-separating an alternating current signal input from the antenna unit, and a plurality of rectifying circuits for rectifying the alternating current signals separated by the separation circuit respectively.

10. The power supply device according to claim 1, wherein a contact surface of the first antenna element with the metal part of the industrial product is composed of a conductor electrode made of any one or a combination of gold, silver, aluminum, copper, iron, nickel, or an alloy.

11. The power supply device according to claim 1, wherein the contact surface of the first antenna element with the metal part of the industrial product is in contact with the metal part of the industrial product by any one or a combination of caulking or press contact.

12. The power supply device according to claim 10, wherein the conductor electrode is resin-coated.

13. The power supply device according to claim 1, wherein a connection part of the first antenna element with the metal part of the industrial product is composed of a conductor electrode made of any one or a combination of gold, silver, aluminum, copper, iron, nickel, or an alloy.

14. The power supply device according to claim 13, wherein the connection part is connected by any one or a combination of screwing, soldering, welding, conductive resin, conductive tape, conductive rubber, or a magnet.

15. The power supply device according to claim 10, wherein the conductor electrode is any one or a combination of a pin, linear, hemispherical, concave-convex, or planar shape.

16. The power supply device according to claim 1, wherein the second antenna element is composed of any one or a combination of a ground of a circuit board of a receiver, a pattern different from the ground on the board, a receiver housing metal not electrically connected to the metal part of the industrial product, or a conductor cable.

17. The power supply device according to claim 1, wherein the second antenna element according to claim 1 and the ground ground are directly or indirectly grounded using an insulated covered cable.

18. The power supply device according to claim 1, which is housed in a case in which a contact surface of a metal part of the industrial product other than the contact or connection part is made of an insulating material.

19. A charger to which the output of the rectifier circuit is supplied, and a power storage element connected to the charger The power supply device according to claim 1.

20. The power supply device according to claim 19, comprising a load that operates by the power stored in the power storage element.

21. The power supply device according to claim 20, wherein the load comprises at least one of a microcomputer, a wireless communication unit, and a sensor.

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